阅读说明：本技术 多个竿体接合的钓竿 (Fishing rod with multiple rod bodies connected ) 是由 塚本康弘 斋藤笃 中尾雅好 河藤谦治 大田勋 于 2019-10-25 设计创作，主要内容包括：本发明的一个实施方式的钓竿具备：中空的竿体,其沿中心轴线从一端延伸至另一端；以及轴部件,其具有相对于所述中心轴线倾斜的外周面,该轴部件从所述一端插入于所述竿体,在沿着所述中心轴线的轴向上的比所述一端靠所述另一端侧的支承位置处被所述竿体的内周面支承。在该实施方式中,所述竿体的所述内周面具有至少一个凸部,当划出在比所述轴部件的所述外周面靠径向外侧的区域通过所述支承位置和作为所述内周面的所述一端侧的端的一端位置而朝向所述中心轴线突出的假想曲线时,该凸部在所述轴向的所述支承位置与所述一端位置之间从所述假想曲线朝向所述中心轴线突出。(A fishing rod according to an embodiment of the present invention includes: a hollow rod body extending from one end to the other end along a central axis; and a shaft member having an outer peripheral surface inclined with respect to the central axis, the shaft member being inserted into the rod body from the one end and supported by the inner peripheral surface of the rod body at a support position closer to the other end side than the one end in an axial direction along the central axis. In this embodiment, the inner circumferential surface of the rod body has at least one projection which projects from the imaginary curve toward the center axis between the support position and the one end position in the axial direction when an imaginary curve is drawn in which a region radially outside the outer circumferential surface of the shaft member projects toward the center axis through the support position and the one end position which is the one end side of the inner circumferential surface.)

1. A fishing rod is provided with:

a hollow rod body extending from one end to the other end along a central axis; and

a shaft member having an outer peripheral surface inclined with respect to the central axis, the shaft member being inserted into the rod body from the one end and supported by the inner peripheral surface of the rod body at a support position closer to the other end side than the one end in an axial direction along the central axis,

the inner circumferential surface of the rod body has at least one protrusion which protrudes from the imaginary curve toward the center axis between the support position and the one end position in the axial direction when the imaginary curve is drawn such that the area radially outside the outer circumferential surface of the shaft member protrudes toward the center axis through the support position and the one end position which is the one end side end of the inner circumferential surface.

2. The fishing rod of claim 1,

the inner circumferential surface of the rod body has a plurality of protrusions protruding from the imaginary curve toward the central axis between the support position and the one end position in the axial direction.

3. The fishing rod of claim 1 or 2,

the inner circumferential surface of the rod body has at least one concave portion depressed from the imaginary curve toward a side opposite to the central axis between the support position and the one end position in the axial direction.

4. The fishing rod of claim 3,

the inner circumferential surface of the rod body has a plurality of recesses between the support position and the one end position in the axial direction, the recesses being recessed from the imaginary curve toward a side opposite to the center axis.

5. The fishing rod according to any of claims 1 to 4,

a straight line connecting the one end position of the inner peripheral surface and the support position is inclined with respect to the central axis at an angle larger than an angle formed by the outer peripheral surface and the central axis.

6. The fishing rod as claimed in any of claims 1 to 5,

the one end position of the inner peripheral surface is located radially outward of the support position.

7. The fishing rod according to any of claims 1 to 6,

the inner circumferential surface of the rod body has a parallel surface extending from the support position to the other end side in parallel or substantially parallel to the central axis.

8. The fishing rod as claimed in any of claims 1 to 7,

the rod body comprises:

a stress relaxation layer that is provided on the radially innermost side and that includes first reinforcing fibers; and

a main body layer that is provided radially outside the stress relaxation layer and includes second reinforcing fibers,

the tensile elastic modulus of the first reinforcing fibers is smaller than the tensile elastic modulus of the second reinforcing fibers.

9. A fishing rod is provided with:

a hollow rod body extending from one end to the other end along a central axis; and

a shaft member having an outer peripheral surface inclined at a first angle with respect to the central axis, the shaft member being inserted into the rod body from the one end,

the inner circumference of the rod body is provided with:

a first face extending obliquely from the one end to a first position in the axial direction at an angle greater than a first angle with respect to the central axis;

a second surface extending from the first position to a second position closer to the other end side than the first position; and

a third surface extending from the second position to a third position on the other end side of the second position in parallel or substantially parallel to the central axis,

the second surface has:

an inclined portion continuous with the first face and inclined at an angle larger than the first angle with respect to the central axis; and

a non-inclined portion continuous with the third face and extending parallel or substantially parallel to the central axis.

10. The fishing rod of claim 9,

the length of the first position of the non-inclined portion in the circumferential direction around the central axis is 50% or more of the entire length of the inner peripheral surface of the second position.

11. The fishing rod of claim 9 or 10,

the length of the first surface in the central axis direction is equal to or greater than the length of the second surface in the central axis direction.

12. The fishing rod of any of claims 9 to 11,

the fishing rod is also provided with a fishing line guide arranged on the outer peripheral surface of the rod body,

the inclined portion is provided on the opposite side of the installation position of the fishing line guide in the circumferential direction around the central axis.

13. The fishing rod of any of claims 9 to 11,

the rod body is provided with a fishing line guide,

the inclined portion is provided on the same side as the mounting position of the fishing line guide in the circumferential direction around the central axis.

14. The fishing rod as claimed in any of claims 1 to 8,

the shaft part is a socket joint core material.

15. The fishing rod as claimed in any of claims 1 to 8,

the shaft component is another rod body with a diameter smaller than that of the rod body.

Technical Field

Cross reference to each other

The present application claims priority based on japanese patent application 2018-202757 (application 10/29/2018), japanese patent application 2018-243805 (application 12/26/2018), and japanese patent application 2019-004805 (application 1/16/2019), the contents of which are incorporated herein by reference in their entirety.

The present invention relates to a fishing rod in which a plurality of rod bodies are joined. The present invention also relates to a bell and spigot type fishing rod and a butt type fishing rod in which a plurality of rods are joined by a bell and spigot joint structure or a butt joint type.

Background

In a fishing rod of socket joint type, a hollow small diameter rod body and a hollow large diameter rod body are connected by a socket joint core material. A conventional socket joint type fishing rod is disclosed in, for example, japanese patent laid-open No. 2003-250396. In a fishing rod of socket joint type, one end of a socket joint core material is fixed to the tip end side end of a rod body having a large diameter by bonding or the like, and a portion of the socket joint core material protruding from the tip end side end is inserted into a rod body having a small diameter from the rear end (near-hand end), whereby the rod body having a small diameter and the rod body having a large diameter are connected by the socket joint core material.

In the socket joint, the rear end opening of the small diameter rod is pressed into the part protruding from the front end opening of the large diameter rod, so that the small diameter rod and the large diameter rod are connected in a fixed state at any position of the outer peripheral surface. In this case, as disclosed in patent document 2, when a soft material is filled in a stress dispersion gap portion formed in an inner peripheral surface of a rear end portion of a small diameter rod or the thickness of the stress dispersion gap portion is increased, rigidity is increased in a joint portion region, and flexibility is lowered. Further, in the case of fishing in real fishing, when a fish is hooked and the fishing rod is greatly bent, a rising portion of the taper is subjected to a large pressure on the outer peripheral surface of the socket, and a fixed position of the rod of small diameter (rising position of the taper) pressed in is greatly concentrated in a ring shape on the outer peripheral surface of the socket, so that there is a problem that the socket is easily broken at the position.

Further, when filling the soft material, the rod is peeled off at the time of insertion and removal of the rod having a small diameter or becomes resistance at the time of insertion and removal, and the operation of the rod is unstable. That is, when the soft material is peeled off, the mounting position with respect to the socket joint is likely to be deviated, and if the soft material is filled, resistance is generated at the time of press-fitting, a proper fitting manner cannot be obtained between the small diameter rod and the outer peripheral surface of the socket joint, and the fitting fixing position is not stable.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2003-250396

Disclosure of Invention

Problems to be solved by the invention

When a fishing rod of spigot-and-socket joint type is bent, stress is concentrated on the spigot-and-socket joint core material from the inner periphery of the small diameter rod body at the rear end of the small diameter rod body. Due to this stress concentration, the socket core material is likely to break when the fishing rod is used.

The same problem occurs in a parallel-joint type fishing rod. That is, in the parallel-joined fishing rod, the small diameter rod body having a small diameter is inserted into the large diameter rod body having a large diameter, and therefore, stress is likely to concentrate at a position of the small diameter rod body which comes into contact with the inner peripheral surface of the large diameter rod body when the fishing rod is bent. Therefore, the part of the rod body with the small diameter inserted into the rod body with the large diameter is easy to break.

One of the purposes of the present invention is to inhibit the breakage of the joint part of the rod body. Other objects of the present invention than those described above will be apparent by referring to the entire specification.

In the socket joint, the rear end opening of the small diameter rod is pressed into the portion protruding from the front end opening of the large diameter rod, so that the rod becomes a fixed state at any position of the outer peripheral surface thereof, and the connection of the small diameter rod and the large diameter rod is completed. In this case, as disclosed in patent document 2, when a soft material is filled in a stress dispersion gap portion formed in an inner peripheral surface of a rear end portion of a small diameter rod or the thickness of the stress dispersion gap portion is increased, rigidity is increased in a joint portion region, and flexibility is lowered. Further, in the case of fishing in real fishing, when a fish is hooked and the fishing rod is greatly bent, a rising portion of the taper is subjected to a large pressure on the outer peripheral surface of the socket, and a fixed position of the rod of small diameter (rising position of the taper) pressed in is greatly concentrated in a ring shape on the outer peripheral surface of the socket, so that there is a problem that the socket is easily broken at the position.

Further, when filling the soft material, the rod is peeled off at the time of insertion and removal of the rod having a small diameter or becomes resistance at the time of insertion and removal, and the operation of the rod is unstable. That is, when the soft material is peeled off, the mounting position with respect to the socket joint is likely to be deviated, and if the soft material is filled, resistance is generated at the time of press-fitting, a proper fitting manner cannot be obtained between the small diameter rod and the outer peripheral surface of the socket joint, and the fitting fixing position is not stable.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a spigot-and-socket joint type fishing rod capable of relaxing stress concentration at a spigot-and-socket joint portion and stably performing an operation of attaching and detaching a small diameter rod to and from a spigot-and-socket joint. Further, it is another object of the present invention to provide a parallel joining type fishing rod in which a small diameter rod and a large diameter rod are joined by a parallel joining type, in which stress concentration at a joining portion is relaxed and an operation of attaching and detaching the small diameter rod and the large diameter rod can be stably performed.

Means for solving the problems

A fishing rod according to an embodiment of the present invention includes: a hollow rod body extending from one end to the other end along a central axis; and a shaft member having an outer peripheral surface inclined with respect to the central axis, the shaft member being inserted into the rod body from the one end and supported by the inner peripheral surface of the rod body at a support position closer to the other end side than the one end in an axial direction along the central axis. In this embodiment, the inner circumferential surface of the rod body has at least one projection which projects from the imaginary curve toward the center axis between the support position and the one end position in the axial direction when an imaginary curve is drawn in which a region radially outside the outer circumferential surface of the shaft member projects toward the center axis through the support position and the one end position which is the one end side of the inner circumferential surface.

In one embodiment of the present invention, the inner circumferential surface of the rod body has a plurality of protrusions protruding from the imaginary curve toward the center axis between the support position and the one end position in the axial direction.

In one embodiment of the present invention, the inner circumferential surface of the rod body has at least one concave portion depressed from the imaginary curve toward a side opposite to the center axis between the support position and the one end position in the axial direction.

In one embodiment of the present invention, the inner circumferential surface of the rod body has a plurality of concave portions depressed from the imaginary curve toward a side opposite to the center axis between the support position and the one end position in the axial direction.

In one embodiment of the present invention, a straight line connecting the one end position of the inner peripheral surface and the support position is inclined with respect to the central axis at an angle larger than an angle formed by the outer peripheral surface and the central axis.

In one embodiment of the present invention, the one end position of the inner peripheral surface is located radially outward of the support position.

In one embodiment of the present invention, the inner circumferential surface of the rod body has a parallel surface extending from the support position to the other end side in parallel or substantially parallel to the central axis.

In one embodiment of the present invention, the rod body comprises: a stress relaxation layer that is provided on the radially innermost side and that includes first reinforcing fibers; and a main body layer that is provided radially outside the stress relaxation layer and includes second reinforcing fibers, and a tensile elastic modulus of the first reinforcing fibers is smaller than a tensile elastic modulus of the second reinforcing fibers.

A fishing rod according to an embodiment of the present invention includes: a hollow rod body extending from one end to the other end along a central axis; and a shaft member having an outer peripheral surface inclined at a first angle with respect to the central axis, the shaft member being inserted into the rod body from the one end. The inner circumference of the rod body is provided with: a first face extending obliquely from the one end to a first position in the axial direction at an angle greater than a first angle with respect to the central axis; a second surface extending from the first position to a second position closer to the other end side than the first position; and a third surface extending from the second position to a third position closer to the other end side than the second position in parallel or substantially parallel to the central axis. The second surface has: an inclined portion continuous with the first face and inclined at an angle larger than the first angle with respect to the central axis; and a non-inclined portion continuous with the third surface and extending parallel or substantially parallel to the central axis.

In one embodiment of the present invention, a length of the first position of the non-inclined portion in a circumferential direction around the central axis is 50% or more of an entire length of the inner peripheral surface of the second position.

In one embodiment of the present invention, a length of the first surface in the central axis line direction is equal to or longer than a length of the second surface in the central axis line direction.

The fishing rod according to one embodiment of the present invention further includes a fishing line guide provided on an outer peripheral surface of the rod body. The inclined portion is provided on the opposite side of the installation position of the fishing line guide in the circumferential direction around the central axis.

In one embodiment of the present invention, the inclined portion is provided on the same side as the mounting position of the fishing line guide in the circumferential direction around the center axis.

In one embodiment of the present invention, the shaft member is a socket joint core material.

In one embodiment of the invention, the shaft member is another rod body having a smaller diameter than the rod body.

In order to achieve the above object, the present invention provides a spigot-and-socket joint type fishing rod in which a large diameter rod and a small diameter rod are detachably connected by a spigot-and-socket joint, wherein an open inner circumferential surface is formed on a rear end side of the small diameter rod, the open inner circumferential surface has a rising position which is fitted into and fixed to an outer circumferential surface of the spigot-and-socket joint and rises from the outer circumferential surface of the spigot-and-socket joint, and a rough surface portion having fine protrusions and depressions protruding in a radial direction in a circumferential range and/or a plurality of fine grooves extending in an axial direction in the circumferential range is formed on the open inner circumferential surface at least in a region of the rising position.

In the fishing rod of the above-described spigot-and-socket joint engagement type, the opening on the rear end side of the small diameter rod is pushed in against the outer peripheral surface of the spigot-and-socket joint, and the connection of the small diameter rod and the large diameter rod is completed. In this case, a large stress concentration is generated in a ring shape at the press-fitting and fixing position of the small diameter rod on the outer peripheral surface of the socket joint, and the socket joint is easily broken at this position, but in the above structure, a rough surface portion is formed in a region of a rising position rising from the outer peripheral surface of the socket joint in the opening inner peripheral surface on the rear end side of the small diameter rod, and therefore, when the small diameter rod is flexed, the rough surface portion is deformed and abutment (stress concentration) with the outer peripheral surface of the socket joint is eased, and breakage at the socket joint portion can be prevented. That is, by forming the rough surface portion, the contact (stress acting in a ring shape) with the outer peripheral surface of the socket at the raised position (edge) can be relaxed, and the action of bending stress and shearing stress can be suppressed.

In addition, the rough surface part is formed in the rising position area which actually completes the joint, therefore, the proper alignment can be carried out when the small diameter rod is pressed in and fixed, and the fastening of the small diameter rod can be prevented, thereby the stable assembling and disassembling operation of the small diameter rod can be carried out, and the tabling fixed position is also stable.

The rough surface portion may include at least one of a minute unevenness protruding in the radial direction in the circumferential direction and a plurality of minute grooves extending in the axial direction in the circumferential direction, the former minute unevenness being deformed so as to be squashed with respect to the outer peripheral surface of the socket joint when the small-diameter rod is deflected to relax the stress, and the latter minute grooves being capable of allowing the deformation of the surface region when the pressure is applied to relax the stress. Such a rough surface portion is preferably formed over the entire circumference in the circumferential direction, but may be formed within a certain range in the circumferential direction in which a large stress acts during bending.

The joining structure having the rough surface portion can be applied to a parallel-joining type fishing rod. In the parallel-jointed fishing rod, the rear end of the rod with the small diameter is press-fitted and fitted to the inner peripheral surface of the opening on the front end side of the rod with the large diameter, but it is sufficient if a raised position is formed on the inner peripheral surface of the opening on the front end side of the rod with the large diameter and a rough surface portion having a plurality of fine grooves and/or projections protruding in the radial direction in the circumferential direction and extending in the axial direction in the circumferential direction is formed in this region.

Effects of the invention

According to the embodiment of the invention, the breakage of the joint part of the rod body can be inhibited.

Further, according to another embodiment of the present invention, a fishing rod of socket joint type can be obtained which can alleviate stress concentration at the socket joint portion and can stably perform the operation of attaching and detaching a small diameter rod to and from the socket joint.

Drawings

Fig. 1 is a schematic view showing a fishing rod according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view schematically showing a joining structure of a rod body with a large diameter and a rod body with a small diameter of the fishing rod of fig. 1.

Fig. 3 is an enlarged and schematic view of the joined structure shown in fig. 2.

Fig. 4 is a schematic view showing the shape of the inner circumferential surface of the small diameter rod body of fig. 1.

Fig. 5a is a view schematically showing the arrangement of the outer peripheral surface of the shaft member with respect to the inner peripheral surface of the rod body having a large diameter. Fig. 5a shows the arrangement of the outer peripheral surface of the shaft member with respect to the inner peripheral surface of the rod body having a large diameter when the fishing rod is not bent.

Fig. 5b is a view schematically showing the arrangement of the outer peripheral surface of the shaft member with respect to the inner peripheral surface of the rod body having a large diameter. Fig. 5b shows the arrangement of the outer peripheral surface of the shaft member with respect to the inner peripheral surface of the rod body having a large diameter when the fishing rod is bent.

Fig. 5c is a view schematically showing the arrangement of the outer peripheral surface of the shaft member with respect to the inner peripheral surface of the rod body having a large diameter. Fig. 5c shows the arrangement of the outer peripheral surface of the shaft member with respect to the inner peripheral surface of the rod body having a large diameter when the fishing rod is further bent.

Fig. 6 is a schematic view for explaining a method of manufacturing the fishing rod of fig. 1.

Fig. 7 is an enlarged schematic view showing a joining structure of a rod body with a large diameter and a rod body with a small diameter of a fishing rod according to another embodiment of the present invention.

Fig. 8 is a schematic view of the joining structure of the fishing rod shown in fig. 7 cut along a line extending in the direction of the central axis and unfolded.

Fig. 9 is a view schematically showing a cross section obtained by cutting the tip rod along a plane perpendicular to the central axis.

Fig. 10 is a view schematically showing a cross section obtained by cutting the tip rod along a plane perpendicular to the central axis.

Fig. 11 is a schematic view showing a fishing rod according to an embodiment of the present invention.

Fig. 12 is a schematic view showing another mode of enlarging and illustrating the joined structure shown in fig. 2.

Fig. 13 is a schematic view of another mode in which the joining structure of the fishing rod shown in fig. 3 is cut and unfolded along a line extending in the direction of the central axis.

Fig. 14 is a view schematically showing a cross section obtained by cutting the tip rod along a plane perpendicular to the central axis.

Fig. 15 is a view schematically showing a cross section obtained by cutting the tip rod along a plane perpendicular to the central axis.

Fig. 16 is a cross-sectional view schematically showing a joining structure of a fishing rod according to another embodiment of the present invention.

Fig. 17 is a view showing one embodiment of a bell and spigot joint type fishing rod of the present invention.

FIG. 18 is an enlarged longitudinal cross-sectional view of the female coupling engagement portion of the structure shown in FIG. 1.

Fig. 19 is a diagram schematically showing a test method of the four-point bending test.

Fig. 20 is a graph showing the measurement results of the bending failure strength based on the test shown in fig. 3.

Fig. 21 is a cross sectional view showing the enlarged joining area of the rod with a small diameter.

Fig. 22 is an enlarged view showing the joining area of the small diameter rod and the socket joint.

Fig. 23 is a schematic view of the engaged configuration shown in fig. 6 cut along a line extending in the direction of the central axis and expanded, and a sectional view taken along the line a-a of the schematic view.

Fig. 24 is a sectional view taken along line B-B of fig. 7.

Fig. 25 is a sectional view taken along line C-C of fig. 7.

Fig. 26 is a cross-sectional view at the position P1 in fig. 7, showing a minute uneven structure.

Fig. 27 is a sectional view showing a modification of the rough surface portion of the joint portion of the rod with a small diameter.

Detailed Description

Hereinafter, various embodiments of the present invention will be described with reference to the drawings as appropriate. In addition, the same reference numerals are given to the components common to the drawings. It should be noted that, for the sake of convenience of explanation, the drawings are not necessarily drawn to precise scale.

A fishing rod 1 according to an embodiment of the present invention will be described with reference to fig. 1 to 4. Fig. 1 is a schematic view of a spigot-and-socket joint fishing rod 1 according to an embodiment of the present invention. Fig. 2 is a sectional view schematically showing a joining structure of a rod on the hand side 5 as an example of a rod body with a large diameter and a rod tip 2 as an example of a rod body with a small diameter of the fishing rod 1, fig. 3 is a schematic view showing the joining structure shown in fig. 2 in an enlarged manner, and fig. 4 is a schematic view showing the shape of the inner peripheral surface of the rod tip 2 in fig. 1.

As shown in the figure, the fishing rod 1 has a tip rod 2 and a hand rod 5 joined to the tip rod 2. The tip rod 2 and the hand rod 5 are each formed in a hollow tubular shape extending along the central axis X. In the present specification, a direction along the central axis X may be referred to as an axial direction or a central axis direction, and a direction extending perpendicularly from the central axis X to the central axis X may be referred to as a radial direction. The tip rod 2 extends from its rear end 2a1 to its front end 2a 2. The side hand pole 5 extends from its rear end 5a1 to its front end 5a 2. The tip rod 2 and the hand rod 5 are obtained by, for example, sintering a prepreg obtained by impregnating carbon fibers with a synthetic resin to form a tubular sintered body, and subjecting the sintered body to polishing treatment and coating. The details of the manufacturing process of the tip rod 2 will be described later.

The rear end of the hand rod 5 is provided with a handle 4. A fishing reel seat (reel seat)3 is arranged in front of a handle 4 of the hand side rod 5. A plurality of fishing line guides 7 are attached to the upper ends of the outer peripheral surfaces of the tip rod 2 and the hand rod 5. A reel, not shown, is mounted on the reel seat 3. In the illustrated embodiment, a two-bearing reel is mounted to the reel holder 3. Two-bearing reels are also known as drop wheels (Bait Reel) or road wheels (BaitCast). In the case of a two-bearing reel, the fishing line guide 7 is provided at the upper ends of the outer peripheral surfaces of the tip rod 2 and the side-of-hand rod 5 as shown in the drawing. In other embodiments, the fishing vessel base 3 may also be fitted with a spinning wheel. In the case of using the spinning wheel, the fishing line guide 7 is provided at the lower end of the outer peripheral surfaces of the tip rod 2 and the hand rod 5. In the present specification, when referring to the front-rear direction of the fishing rod 1 or the tip rod 2 and the hand rod 5 constituting the fishing rod 1, the front-rear direction shown in fig. 1 is taken as a reference.

In one embodiment, the hand side rod 5 is configured to have a larger inner diameter than the tip rod 2. The tip rod 2 is an example of a small diameter rod body, and the hand rod 5 is an example of a large diameter rod body. The inner diameter of the hand rod 5 and the inner diameter of the tip rod 2 are, for example, in the range of 3mm to 15mm, and the outer diameters thereof are, for example, in the range of 5mm to 20 mm. The dimensions of the tip rod 2 and the hand rod 5 described in this specification are examples.

As shown in fig. 3, the tip rod 2 includes a stress relaxation layer 21 near the rear end 2a1 thereof, a main body cover 22 provided on the outer surface of the stress relaxation layer 21, a main body layer 23 provided on the outer surface of the main body cover 22, and a reinforcing layer 24 provided on the outer surface of the main body layer 23. The stress relaxation layer 21, the body protection layer 22, the body layer 23, and the reinforcing layer 24 are each obtained by sintering a fiber-reinforced resin sheet obtained by impregnating a reinforcing fiber bundle made of reinforcing fibers with a matrix resin. The method of manufacturing the tip rod 2 will be described later.

The stress relaxation layer 21 is disposed on the radially innermost side of the tip rod 2 near the rear end 2a1 thereof. Thus, the inner peripheral surface 21A of the stress relaxation layer 21 constitutes the inner peripheral surface 2b of the tip rod 2 in the vicinity of the rear end 2a1 of the tip rod 2. The inner circumferential surface 21A of the stress relaxation layer 21 has: an inclined surface 21a1 inclined with respect to the central axis X direction and extending forward from the rear end 2a1 of the tip rod 2; and a parallel surface 21a2 extending from the front end of the inclined surface 21a1 forward in parallel with the central axis a.

The tip rod 2 and the hand rod 5 are detachably connected to each other via a socket joint core 6. The socket joint core material 6 is obtained by, for example, sintering a prepreg obtained by impregnating carbon fibers with a synthetic resin to form a tubular sintered body, and subjecting the sintered body to a polishing treatment and a coating treatment. The socket joint core material 6 has a substantially cylindrical rear end portion 6a, an inclined portion 6b provided on the front side of the rear end portion 6a and having an outer peripheral surface inclined at a first angle θ 1 with respect to the central axis X, and a front end portion 6c provided in front of the inclined portion 6b and having a substantially cylindrical shape. The front end portion 6c is formed to be smaller in diameter than the rear end portion 6 a. The socket joint core material 6 is formed so that the length in the direction of the central axis thereof is 50mm to 150mm, and the outer diameter of the rear end portion 6a thereof is 3mm to 15 mm. A first angle θ 1 formed by the outer peripheral surface of the inclined portion 6b and the central axis X is, for example, in a range of 0.05 ° to 5.0 °. The inclination of the outer peripheral surface of the inclined portion 6b shown in fig. 2 is exaggerated to show the inclination for easy understanding. The socket core material 6 may be hollow or solid. The dimensions and shape of the socket joint core material 6 described in the present specification are examples. For example, the socket joint core member 6 may be configured such that the outer peripheral surface thereof is inclined at a predetermined angle with respect to the central axis X from the rear end to the front end thereof.

In one embodiment, the socket joint core 6 is inserted into the hand side pole 5 to a predetermined position in the direction of the central axis X, and is fixed to the inner circumferential surface 5b of the hand side pole 5 by, for example, adhesion. The socket core 6 is fixed to the side pole 5 so that a part thereof projects forward from the front end 5a2 of the side pole 5. The tip rod 2 and the side pole 5 are connected via the socket core 6 by inserting the socket core 6 protruding from the front end 5a2 of the side pole 5 into the tip rod 2 from the rear end 2a1 to a positioning position. The socket joint core material 6 is an example of a shaft member inserted into the rod body. In another embodiment, the socket joint core 6 is bonded to the inner peripheral surface 2b of the joint portion 2a of the tip rod 2. In this case, the socket core 6 is fixed to the peak pole 2 so as to project rearward from the rear end 2a1 of the peak pole 2. The hand side rod 5 is inserted into the socket core 6 at a position projecting from the rear end 2a1 of the tip rod 2, whereby the tip rod 2 and the hand side rod 5 are connected via the socket core 6.

In fig. 2, the socket joint core material 6 is inserted to a positioning position. When the socket core 6 reaches the set position, a gap is formed between the front end 5a2 of the side pole 5 and the rear end 2a1 of the tip pole 2. The length of the gap in the direction of the central axis X is, for example, 3mm to 10 mm. The dimensions of the gap are exemplary. Since there is a gap between the tip rod 2 and the side rod 5, when the tip rod 2 and the side rod 5 are bent during use of the fishing rod 1, bending stress and shearing stress act on the socket core 6.

When the socket joint core material 6 is inserted to the positioning position, the outer surface 6e of the socket joint core material 6 contacts the inner peripheral surface of the stress relaxation layer 21 at a position a1 located at the boundary between the inclined surface 21a1 and the parallel surface 21a2 of the inner peripheral surface of the stress relaxation layer 21. Thereby, the socket joint core material 6 is supported by the inner peripheral surface of the stress relaxation layer 21 at the position a 1. This position a1 is an example of a support position. When the socket joint core material 6 is inserted to the positioning position, the outer diameter of the socket joint core material 6 is matched or substantially matched with the inner diameter of the stress relaxation layer 21 at the position a 1.

Next, the inner peripheral surface 21A of the stress relaxation layer 21 will be further described with reference to fig. 4. As described above, the inner peripheral surface 21A has the inclined surface 21A1 and the parallel surface 21A 2. The inclined surface 21a1 has a concavo-convex structure. In the illustrated embodiment, the inclined surface 21A1 has eight concave portions 21a 1-21 A8 and eight convex portions 21b 1-21 b 8. The uneven structure is determined based on the virtual curve Y. Specifically, the concave portions 21a 1-21 a8 are recessed from the virtual curve Y toward the side opposite to the center axis X (radially outward), and the convex portions 21b 1-21 b8 protrude from the virtual curve Y toward the center axis X. The virtual curve Y is a virtual curve that passes through the support position a1 in a region radially outward of the outer peripheral surface 6e of the socket joint core material 6 and projects toward the central axis X at one end position a2 at the rear end of the inner peripheral surface 21A of the stress relaxation layer 21. When the tip rod 2 is not bent, the projections 21b 1-21 b8 project from the virtual curve Y toward the center axis X so as not to interfere with the socket joint core material 6. In other words, when the tip rod 2 is not deflected, the projections 21b 1-21 b8 are located radially outward of the outer surface 6e of the female joint core 6. The recesses 21a 1-21 a8 and the protrusions 21b 1-21 b8 are located between a support position A1 and one end position A2 in the axial direction.

As shown in fig. 3, the one end position a2 is disposed radially outward of the support position a 1. When the tip rod 2 is cut on a plane including the central axis X, a virtual straight line connecting the support position a1 and the one end position a2 is inclined at a second angle θ 2 larger than the first angle θ 1 with respect to the central axis X. The second angle θ 2 is, for example, an angle larger than the first angle θ 1. The second angle θ 2 is, for example, in the range of 0.1 ° to 10.0 °. In one embodiment, the second angle θ 2 is 2.0 °.

Next, a positional relationship between the outer surface 6e of the spigot and socket core 6 and the inner peripheral surface (the inner peripheral surface 21A of the stress relaxation layer 21) of the inner peripheral surface 2b of the butt rod 2 when the fishing rod 1 is used will be described with reference to fig. 5a to 5 c. As shown in fig. 5a, when the tip rod 2 is not bent or when the tip rod 2 is slightly bent, the outer surface 6e of the socket core 6 is supported by the inner circumferential surface 2b of the tip rod 2 at the support position a1, but does not contact the inner circumferential surface 2b of the tip rod 2 at any other position. When the deflection of the tip rod 2 becomes large, as shown in fig. 5b, the projection 21b1 closest to the support position a1 among the projections 21b1 to 21b8 comes into contact with the outer surface 6e of the female joint core 6. When the deflection of the tip rod 2 becomes large, as shown in fig. 5c, the projection 21b2, which is the second closest to the support position a1, of the projections 21b 1-21 b8 comes into contact with the outer surface 6e of the socket core 6. Thus, as the bending of the tip rod 2 increases, the projections 21b 1-21 b8 come into contact with the outer surface 6e of the female joint core 6 in the order of the support position a1 from the near side to the far side. Depending on the shape of the projections 21b 1-21 b8, two or more of the projections 21b 1-21 b8 may simultaneously contact the outer surface 6e of the female tab core 6 when the peak pole 2 is flexed.

As described above, the socket joint core member 6 may be bonded to the inner peripheral surface 2b of the joint portion 2a of the tip rod 2. In this case, the hand side rod 5 is inserted into the portion of the socket core 6 protruding from the rear end 2a1 of the tip rod 2, whereby the tip rod 2 and the hand side rod 5 are connected via the socket core 6. In this case, the vicinity of the front end of the inner circumferential surface 5b of the hand rod 5 is formed in the same manner as the vicinity of the rear end of the inner circumferential surface 2b of the tip rod 2. Specifically, a slope having an uneven structure corresponding to the slope 21a1 is formed near the tip of the inner peripheral surface 5b of the rod 5 on the side of the hand. The inclined surface 21a1 may be formed near the rear end of the inner peripheral surface of the tip rod 2, and an inclined surface having an uneven structure corresponding to the inclined surface 21a1 may be formed near the front end of the inner peripheral surface of the side rod 5. By providing the inclined surfaces having such an uneven structure on both the tip rod 2 and the hand rod 5, breakage of the socket joint core material 6 can be further suppressed. In this case, the socket core 6 may be bonded to the inner peripheral surface of the hand side pole 5, or may be bonded to the inner peripheral surface of the tip pole 2.

Next, a method of manufacturing the tip rod 2 will be described with reference to fig. 6. To manufacture the tip rod 2, first, a mandrel 50 and fiber-reinforced resin sheets 51, 52, 53, and 54 are prepared. The illustrated mandrel 50 has a tapered shape. In this specification, when referring to the width and length of the fiber-reinforced resin sheets 51, 52, 53, and 54, the description will be made with reference to the W direction (width direction) and the L direction (length direction) shown as orthogonal coordinates in fig. 6. The central axis of the mandrel 50 extends in a direction parallel to the L direction.

The fiber-reinforced resin sheets 51, 52, 53, and 54 are sheet-shaped composite members obtained by impregnating reinforcing fiber bundles made of reinforcing fibers with a matrix resin. The reinforcing fibers contained in the fiber-reinforced resin sheets 51, 52, 53, and 54 are, for example, carbon fibers or glass fibers. The matrix resin component contained in the fiber-reinforced resin sheets 51, 52, 53, and 54 is, for example, an epoxy resin-based resin, a bisphenol a-based resin, a bisphenol F-based resin, or a combination thereof. In the illustrated embodiment, the fiber-reinforced resin sheets 51, 52, 53, and 54 each have a substantially trapezoidal shape. The shape of the fiber-reinforced resin sheets 51, 52, 53, and 54 is not limited to a trapezoid.

In one embodiment, the tensile elastic modulus of the reinforcing fibers contained in the fiber-reinforced resin sheet 51 is smaller than the tensile elastic modulus of the reinforcing fibers contained in the fiber-reinforced resin sheet 53. In one embodiment, the reinforcing fibers contained in the fiber-reinforced resin sheet 51 have a thickness of 1t/mm²Above, 1.5t/mm²Above, 2t/mm²Above, 3t/mm²Above, 4t/mm²Above, 5t/mm²Above, 6t/mm²Above, 7t/mm²Above, 8t/mm²Above, 9t/mm²Above or 10t/mm²The above tensile modulus of elasticity. In one embodiment, the reinforcing fibers contained in the fiber-reinforced resin sheet 53 have a thickness of 20t/mm²～30t/mm²、22t/mm²～28t/mm²Or 23t/mm²～27t/mm²The modulus of elasticity of (a).

In one embodiment, the reinforcing fibers contained in the fiber-reinforced resin sheets 51 are aligned in the circumferential direction about the central axis X. In one embodiment, the reinforcing fibers contained in the fiber-reinforced resin sheet 51 are aligned in the axial direction along the central axis X. The fiber-reinforced resin sheet 54 may have reinforcing fibers woven (for example, plain woven). The orientation direction of the reinforcing fibers contained in the fiber-reinforced resin sheets 51 to 54 is not limited to the direction described in the present specification.

The fiber-reinforced resin sheet 51 and the fiber-reinforced resin sheet 52 have substantially the same width and the same length. The fiber-reinforced resin sheets 51 and 52 have a width of, for example, 1 strand wound around the mandrel bar 50. The dimension of the fiber-reinforced resin sheet 53 in the width direction and the length direction is larger than the dimension of the fiber-reinforced resin sheets 51 and 52. The fiber-reinforced resin sheet 53 has a width of 3 strands wound around the mandrel bar 50, for example. The dimension of the fiber-reinforced resin sheet 54 in the longitudinal direction is larger than the dimensions of the fiber-reinforced resin sheets 51 and 52 in the longitudinal direction and smaller than the dimension of the fiber-reinforced resin sheet 53 in the longitudinal direction.

As shown in fig. 6, the fiber-reinforced resin sheet 51 is disposed with respect to the core rod 50 such that one side thereof is parallel to the central axis of the core rod 50, and is wound around the outer peripheral surface of the core rod 50 in a state where the disposition is maintained. The fiber-reinforced resin sheet 52 is disposed so that the right end thereof is aligned with the right end of the fiber-reinforced resin sheet 51, and is wound around the outer peripheral surface of the fiber-reinforced resin sheet 51 while maintaining this arrangement. The fiber-reinforced resin sheet 53 is disposed so that the right end thereof is aligned with the right end of the fiber-reinforced resin sheet 52, and is wound around the outer peripheral surface of the fiber-reinforced resin sheet 52 in a state where the disposition is maintained. The fiber-reinforced resin sheet 54 is disposed so that the right end thereof is aligned with the right end of the fiber-reinforced resin sheet 53, and is wound around the outer peripheral surface of the fiber-reinforced resin sheet 53 in a state where the disposition is maintained.

The fiber-reinforced resin sheets 51, 52, 53, and 54 wound around the mandrel 50 in this manner are sintered, and the mandrel 50 is removed after sintering, thereby obtaining a hollow tubular sintered body. The fiber-reinforced resin sheets 51, 52, 53, and 54 are sintered to form the stress relaxation layer 21, the body protective layer 22, the body layer 23, and the reinforcing layer 24, respectively. The inner peripheral surface of the sintered fiber-reinforced resin sheet 51 (stress relaxation layer 21) is cut with a tool such as a tapered reamer. By this cutting, the inclined surface 21A1 is formed on the inner peripheral surface 21A of the stress relaxation layer 21. In one embodiment, the tapered reamer is inserted from the rear end 2a1 of the tip rod 2 so that the axial direction thereof is slightly inclined with respect to the central axis X (for example, so that the tapered reamer is inclined at an angle in the range of 0.05 ° to 2 °) and the inclined surface 21A1 is formed by cutting the inner peripheral surface 21A of the stress relaxation layer 21. When the stress relaxation layer 21 is cut, a part of the main body protection layer 22 provided on the outer peripheral surface of the stress relaxation layer 21 may be cut. However, it is preferable that the main body layer 23 provided on the outer peripheral surface of the main body protective layer 22 is not cut.

The hollow tubular sintered body obtained as described above is subjected to polishing treatment and coating as appropriate, thereby obtaining a tip rod 2.

Next, a fishing rod according to another embodiment of the present invention will be described with reference to fig. 7 to 8. Fig. 7 is a sectional view schematically showing a joining structure of a rod body with a large diameter and a rod body with a small diameter of a fishing rod according to another embodiment of the present invention, and fig. 8 is a schematic view of the joining structure of the fishing rod shown in fig. 7 cut and developed along a line extending in the direction of a central axis X. In the embodiment shown in fig. 7 and 8, the shape of the inner peripheral surface 2b of the tip rod 2 (the inner peripheral surface 21A of the stress relaxation layer 21) is different from that of the embodiment shown in fig. 1 to 4. Next, the shape of the inner peripheral surface 2b of the tip rod 2 of the fishing rod according to another embodiment of the present invention will be described with reference to fig. 7 and 8.

The inner circumferential surface 2b of the tip rod 2 has an inclined surface 2b1 inclined with respect to the central axis X direction and extending forward from the rear end 2a1, a stress relaxation surface 2b2 extending from a position P1 to a position P2 of the front end of the inclined surface 2b1, and a cylindrical surface 2b3 extending from a position P2 to a position P3. The position P1 indicates a position shifted forward from the rear end 2a1 of the tip rod 2 along the central axis X by L1, and the position P2 indicates a position shifted forward from the position P1 along the central axis X by L2. The position P3 is an arbitrary position between the position P2 and the front end 2a2 of the tip rod 2 on the central axis X. The length L1 is, for example, a length in the range of 1mm to 30 mm. In one embodiment, length L1 is in the range of 1mm to 5 mm. The length L2 is equal to or less than the length L1. When the stress relaxation surface 2b2 extending forward from the position P1 becomes long (when the length L2 starting from the position P1 becomes long), the ratio of the stress relaxation surface 2b2 occupying the tip rod 2 becomes large. Since the stress relaxation surface 2b2 is thinned, the strength near the rear end of the tip rod 2 may be insufficient when the length L2 is increased. By setting the length L2 to a length equal to or less than the length L1, the strength of the tip rod 2 can be prevented from becoming insufficient.

The inclined surface 2b1 is inclined at a second angle θ 2 larger than the first angle θ 1 with respect to the central axis X and extends to P1. In other words, an imaginary straight line connecting the support position a1 and the one end position a2 is inclined at a second angle θ 2 larger than the first angle θ 1 with respect to the central axis X. The inclined surface 2b1 has one or more irregularities, as with the inclined surface 21a 1.

The cylindrical surface 2b3 extends from the position P2 to the position P3 in parallel or substantially parallel to the central axis X direction. When the inclination of the cylindrical surface 2b3 with respect to the direction of the central axis X is smaller than the first angle θ 1, the cylindrical surface 2b3 can be said to extend substantially parallel to the direction of the central axis X. The tip rod 2 may be configured to be tapered from the rear end toward the front end. In this case, the outer peripheral surface of the tip rod 2 extends at a predetermined angle to the central axis X direction. The cylindrical surface 2b3 may extend parallel to the outer peripheral surface of the tip rod 2.

The stress relaxation surface 2b2 is a portion between the inclined surface 2b1 and the cylindrical surface 2b3 of the inner peripheral surface 2b of the tip rod 2. The stress relaxation surface 2b2 has inclined portions 121a, 121b, 121c, 121d and a non-inclined portion 122. For convenience of explanation, the inclined portions 121a, 121b, 121c, and 121d may be collectively referred to as the inclined portion 121. A boundary 123a between the inclined portion 121 and the non-inclined portion 122 has a wave shape protruding rearward from a boundary 123b between the inclined surface 2b1 and the stress relaxation surface 2b 2. The boundary 123b extends in the circumferential direction around the central axis X. In the present specification, the boundary 123a may be referred to as a stress relaxation boundary, and the boundary 123b may be referred to as a positioning position boundary (or a support position boundary).

The inclined portion 121 is continuous with the inclined surface 2b1 at the rear end thereof. That is, the rear end of the inclined portion 121 is at the position P1. The inclined portions 121 extend forward along the central axis X from the positions P1, respectively. The tip ends of the inclined portions 121 may be different from each other. In the illustrated embodiment, four inclined portions 121a, 121b, 121c, 121d are provided as described above, and among them, the inclined portion 121a extends to a position P1 as a boundary with the cylindrical surface 2b 3. The inclined portion 121a extends to the forefront among the four inclined portions. The inclined portion 121b, the inclined portion 121c, and the inclined portion 121d extend from the position P1 to a position between the position P1 and the position P2.

The inclined portions 121 are inclined at a second angle θ 2 larger than the first angle θ 1 with respect to the central axis X, similarly to the inclined surfaces 2b1, respectively. The inclined portion 121 may have an angle with respect to the direction of the central axis X that differs depending on the position in the circumferential direction around the central axis X. For example, the angle formed by the inclined portion 121a and the direction of the central axis X may be different from the angle formed by the inclined portion 121b and the direction of the central axis X. Further, the angle formed by the position B1 of the inclined portion 121a in the circumferential direction and the central axis X direction may be different from the angle formed by the position B2 of the inclined portion 121a in the circumferential direction and the central axis X direction. That is, the angle formed by the inclined portion 121a and the central axis X direction may be different depending on the circumferential position. This also applies to the inclined portions 121b, 121c, 121 d. The angle of the inclined portion 121 with respect to the central axis may be the same as or different from the angle of the inclined surface 2b1 with respect to the central axis.

The stress relief surface 2b2 is further described with reference also to fig. 9 and 10. Fig. 9 is a view showing a cross section obtained by cutting the tip rod 2 with a plane perpendicular to the central axis X and passing through the position B1, and fig. 10 is a view showing a cross section obtained by cutting the tip rod 2 with a plane perpendicular to the central axis X and passing through the position C1. The position C1 is located further forward than the position B1 in the direction along the center axis X.

As described above, the inclined portion 121a is inclined at an angle larger than the first angle θ 1 with respect to the central axis X, and the non-inclined portion 122 extends parallel or substantially parallel to the central axis X. Therefore, as shown in the sectional view of fig. 9, the stress relaxation surface 12B2 is recessed toward the radially outer side of the tip rod 2 at the inclined portion 121a located between the position B1 and the position B2, between the position B3 and the position B4, and between the position B5 and the position B6 in the circumferential direction. Likewise, in the cross section shown in fig. 6, the stress relaxation surface 2b2 is also recessed toward the radially outer side of the tip rod 2 between the position C1 and the position C2 and between the position C3 and the position C4 in the circumferential direction.

When the fishing rod 1 is used, the tip rod 2 is bent downward in fig. 9, and thus a lower portion of the tip rod 2 is compressed. The compressed portion of the tip rod 2 is a portion within a predetermined angular range around the lower end of the tip rod 2. The lower end of the tip rod 2 represents the 0 deg. position in figure 8. The compressive force acts in particular on the region of ± 30 ° centered on this 0 ° position. The region of the tip rod 2 in the range of ± 30 ° in the circumferential direction from the lower end is referred to as a compression region R1.

In the illustrated embodiment, the fishing line guide 7 is provided at the upper end of the tip rod 2 (and the hand-side rod 5), and therefore the compressed region R1 is located on the opposite side of the mounting position of the fishing line guide 7 in the circumferential direction around the center axis X. As explained with reference to FIG. 8, the fishing line guide 7 is disposed at a position of 180 in the circumferential direction, and the compressed region R1 is located at a position of + -30 DEG centered at the position of 0 deg. In other embodiments using the spinning wheel, the fishing line guide 7 is provided at a position of 0 ° in the circumferential direction, and therefore the compressed region R1 is provided on the lower side of the tip rod 2 similarly to the fishing line guide 7.

At least one of the inclined portions 121a, 121b, 121c, 121d is provided to the compression region R1. In the illustrated embodiment, the inclined portion 121a is provided in the compression region R1. The inclined portion 121a may be provided entirely in the compression region R1 or may be provided partially in the compression region R1.

Thus, the stress relaxation face 2b2 has a non-inclined portion 122 and an inclined portion 121a recessed from the inclined portion 122 in the radial direction of the tip rod 2. The shape and arrangement of the inclined portion 121a of the stress relaxation surface 2b2 are not limited to those shown in the drawings.

In the illustrated embodiment, a portion of the non-angled portion 122 extends from position P2 to position P1. In other words, the rear end of a part of the non-inclined portion 122 is located at the position P1 in the central axis X direction. The ratio of the circumferential length (corresponding to the length b1+ b2+ b3+ b4 in fig. 8) of the non-inclined portion 122 at the position P1 in the central axis X direction to the entire circumferential length (corresponding to the length a in fig. 8) of the inner circumferential surface of the stress relaxation surface 2b2 is 0.5 or more. Namely, (b1+ b2+ b3+ b4)/a is 0.5 or more (50% or more in terms of percentage).

As described above, in order to manufacture the tip rod 2 according to the embodiment, a prepreg obtained by impregnating carbon fibers with a synthetic resin is sintered to prepare a tubular sintered body. The inclined surface 2b1 and the stress relaxation surface 2b2 of the pointed rod 2 are obtained by processing the inner peripheral surface of the tubular sintered body using a tool such as a tapered reamer. In one embodiment, the tapered reamer may be inserted into the interior of the tip rod 2 such that the axial direction thereof is slightly inclined with respect to the central axis X (for example, inclined at an angle in the range of 0.05 ° to 2 °) to form the inclined surface 2b1 by cutting the inner peripheral surface of the tip rod 2, and then, a reamer (for example, a pin reamer) having a smaller diameter may be used to cut a region of the inner peripheral surface of the tip rod 2 that is further inside than the inclined surface 2b1, thereby forming the inclined portion 121 a. In another embodiment, the inclined surface 2b1 and the inclined portion 121a may be formed by first cutting the inner peripheral surface of the tip rod 2 using a pin reamer to form a narrow groove corresponding to the inclined portion 121a, and then cutting the inner peripheral surface of the tip rod 2 using a tapered reamer to a shallower extent than the narrow groove. Thus, the inclined surface 2b1 and the stress relaxation surface 2b2 provided with the inclined portion 121a can be formed. The inclined surface 2b1 and the inclined portion 121a may be formed first, or may be formed at one time.

As described above, the socket joint core member 6 may be bonded to the inner peripheral surface 2b of the joint portion 2a of the tip rod 2. In this case, the hand side rod 5 is inserted into the portion of the socket core 6 protruding from the rear end 2a1 of the tip rod 2, whereby the tip rod 2 and the hand side rod 5 are connected via the socket core 6. In this case, the vicinity of the front end of the inner circumferential surface 5b of the hand rod 5 is formed in the same manner as the vicinity of the rear end of the inner circumferential surface 2b of the tip rod 2. Specifically, the vicinity of the tip of the inner peripheral surface 5b of the rod 5 on the side of the hand is formed with an uneven structure corresponding to the inclined surface 2b1 and the stress relaxation surface 2b 2.

The inclined surface 2b1 and the stress relaxation surface 2b2 may be formed near the rear end of the inner peripheral surface of the tip rod 2, and the uneven structure corresponding to the inclined surface 2b1 and the stress relaxation surface 2b2 may be formed near the front end of the inner peripheral surface of the side rod 5. By providing such a concave-convex structure on both the tip rod 2 and the hand rod 5, breakage can be further suppressed. In this case, the socket joint core member 6 may be bonded to the inner peripheral surface of the hand side pole 5, or may be bonded to the inner peripheral surface of the tip pole 2.

Next, a fishing rod 101 according to another embodiment of the present invention will be described with reference to fig. 11. Fig. 11 is a sectional view schematically showing a joining structure of a fishing rod 101 according to another embodiment of the present invention.

The fishing rod 101 is a butt-jointed fishing rod. The fishing rod 101 has a hand rod 102 and a tip rod 105 engaged with the tip of the hand rod 102. The tip rod 105 is configured to be smaller in diameter than the hand rod 102. The rod 102 on the hand side may include a stress relaxation layer 21, a main body cover 22 provided on the outer surface of the stress relaxation layer 21, a main body layer 23 provided on the outer surface of the main body cover 22, and a reinforcing layer 24 provided on the outer surface of the main body layer 23, as in the tip rod 2.

When the outer peripheral surface 105a of the tip rod 105 is inserted into the positioning position from the front end of the hand rod 102, the outer peripheral surface 105a of the tip rod 105 contacts the inner peripheral surface of the hand rod 102 at a support position rearward of the front end of the hand rod 102. In this support position, the outside diameter of the tip rod 105 coincides or substantially coincides with the inside diameter of the hand side rod 102. In the embodiment of fig. 11, the rear end of the tip rod 105 (the end on the side close to the hand rod 102) corresponds to a shaft member inserted into the rod body.

The inner circumferential surface 102b of the hand rod 102 is configured in the same manner as the inner circumferential surface 2b (the inner circumferential surface 21A of the stress relaxation layer 21) of the tip rod 2 shown in fig. 3 and 4. That is, the inner peripheral surface 102b of the rod 102 on the hand side has an inclined surface corresponding to the inclined surface 21A1 having the uneven structure and a parallel surface extending in parallel from the inclined surface along the center axis X, similarly to the inner peripheral surface 21A of the stress relaxation layer 21. The uneven structure of the inner peripheral surface 102b of the rod 102 on the hand side has a plurality of concave portions (for example, eight concave portions 21a1 to 21A8) and a plurality of convex portions (for example, eight convex portions 21b1 to 21b8) in the same manner as the uneven structure of the inclined surface 21a1 shown in fig. 4. Although not shown, the outer peripheral surface 105a of the tip rod 105 is provided with an inclined portion similar to the inclined portion 6b of the socket joint core material 6.

Fig. 11 shows only two rods, the hand rod 102 and the tip rod 105, but a fishing rod of the side-by-side type may have three or more rod bodies joined thereto. The rod bodies constituting the parallel-joining type fishing rod can be joined by using the joining structure similar to that of the hand side rod 102 and the tip rod 105.

Next, the operational effects achieved by the above-described embodiment will be described. The fishing rod 1 according to the above-described embodiment includes the hollow butt rod 2 and the socket core 6 supported by the inner peripheral surface 2b (the inner peripheral surface 21A of the stress relaxation layer 21) of the butt rod 2 at the support position a 1. The inner peripheral surface 2b of the tip rod 2 (the inner peripheral surface 21A of the stress relaxation layer 21) has projections 21b1 to 21b8 projecting from the virtual curve Y toward the center axis X between the axial support position A1 and the one end position A2. Thus, as described with reference to fig. 5a to 5c, when the peak pole 2 is deflected, the protrusions 21b1 to 21b8 come into contact with the outer surface 6e of the female joint core member 6. Thus, when the tip rod 2 is deflected, the socket joint core member 6 is supported by at least a part of the convex portions 21b1 to 21b8, not only by the inner peripheral surface 21A of the stress relaxation layer 21 at the support position a1 in the axial direction. Thus, the stress acting on the socket core 6 from the inner peripheral surface 2b of the tip rod 2 is not concentrated on one point (support position a1) in the central axis X direction, but can be dispersed over a wide range in the central axis X direction. This can suppress breakage of the socket joint core material 6.

In the above-described embodiment, the tip rod 2 has the stress relaxation layer 21 including the reinforcing fibers in the innermost layer thereof, and has the body layer 23 at the position radially outward of the stress relaxation layer 21, and the body layer 23 has the reinforcing fibers. Since the tensile elastic modulus of the reinforcing fibers included in the stress relaxation layer 21 is smaller than that of the reinforcing fibers included in the main body layer 23, the stress relaxation layer 21 is cut to form the inclined surface 21A, and therefore the influence on the bending profile in the axial direction of the tip rod 2 is small. In other words, by providing the stress relaxation layer 21, an inclined surface can be formed on the inner peripheral surface of the tip rod 2 without largely affecting the curved profile of the tip rod 2.

In the above embodiment, when the tip rod 2 is not bent, the projections 21b1 to 21b8 are located radially outward of the outer surface 6e of the female joint core 6. Thus, the socket core 6 can be inserted into the tip rod 2 to a predetermined positioning position without interfering with the inner peripheral surface of the tip rod 2.

In the above embodiment, the inner peripheral surface 2b of the tip rod 2 into which the socket joint core 6 is inserted has the inclined surface 2b1, the stress relaxation surface 2b2, and the cylindrical surface 2b3 in the vicinity of the rear end thereof. The stress relaxation surface 2b2 has inclined portions 121a, 121b, 121c, 121d and a non-inclined portion 122. The inclined surface 121 and the inclined portions 121a, 121b, 121c, 121d extend at an inclination angle larger than that of the outer peripheral surface of the socket joint core material 6 with respect to the central axis X direction, whereas the non-inclined portion 122 extends parallel or substantially parallel to the central axis X direction. When the socket core 6 is fitted to the inner peripheral surface 2b of the tip rod 2, the inner peripheral surface 2b of the tip rod 2 is in contact with the socket core 6 at the positioning position boundary 123 b. Thus, the tip rod 2 is supported by the socket core 6 at the boundary 123 b. When the tip rod 2 and the hand rod 5 are flexed during use of the fishing rod 1, the inner peripheral surface 2b of the tip rod 2 comes into contact with the socket core 6 not only at the positioning position boundary 123b but also at the stress relaxation boundary 123 a. Since the stress relaxation boundary 123b has a wavy shape protruding toward the rear end side in the direction of the central axis X, the stress acting on the socket joint core material 6 from the inner peripheral surface 2b of the tip rod 2 acts not only at the position P1 in the direction of the central axis X where the positioning position boundary 123b is arranged but also at a position shifted rearward in the direction of the central axis X from the position P1. That is, the stress applied to the socket core 6 from the inner peripheral surface 2b of the tip rod 2 can be dispersed over a wide range in the central axis X direction, rather than being dispersed at one point (position P1) in the central axis X direction. For example, fig. 8 shows a position a, a position B1, a position C1, and a position D existing on the stress relaxation boundary 123a, and the position a, the position B1, the position C1, and the position D are arranged at different positions in the central axis X direction. Before the tip rod 2 is deflected, the inner circumferential surface 2b of the tip rod 2 contacts the socket core 6 at the locating position boundary 123 b. When the tip rod 2 and the side rod 5 are flexed, the stress relaxation boundary 123b comes into contact with the socket joint core member 6 in order from a position close to the positioning position boundary 123 b. In the conventional joint structure, since the structure corresponding to the stress relaxation surface 2b2 is not provided, the stress applied to the socket core member is concentrated at one point in the axial direction at the rear end of the butt rod 2, and causes the socket core member to break. In contrast, in the above embodiment, the stress relaxation surface 2b2 acts so as to disperse the stress on the socket core 6 in the direction of the central axis X, and therefore, the breakage of the socket core can be suppressed.

In the joining structure of the parallel joining type fishing rod 101 shown in fig. 11, the stress applied to the tip rod 105 from the inner peripheral surface of the rod 102 on the hand side can be dispersed in the central axis direction for the same reason. This can suppress breakage of the tip rod 105.

In the above-described embodiment, the ratio of the circumferential length of the non-inclined portion 122 at the position P1 in the central axis X direction to the total circumferential length of the inner circumferential surface of the stress relaxation surface 2b2 is 0.5 or more. This makes it possible to disperse stress on the socket core 6 or the tip rod 105 in the central axis direction, and to reliably hold the socket core 6 or the tip rod 105 at the position P1 (support position a1) serving as the positioning position.

The above-described operational effects are exerted by the configuration of the compression region R1 existing in the inclined portions 121a, 121b, 121c, and 121d, in particular. The structures outside the compression region R1 in the inclined portions 121a, 121b, 121c, and 121d may be omitted.

A fishing rod 1 according to an embodiment of the present invention will be described with reference to fig. 1, 2, 12, and 13. Fig. 1 is a schematic view of a spigot-and-socket joint fishing rod 1 according to an embodiment of the present invention. Fig. 2 is a cross-sectional view schematically showing a joining structure of a rod body with a large diameter and a rod body with a small diameter of the fishing rod 1, fig. 12 is a schematic view showing another mode of enlarging the joining structure shown in fig. 2, and fig. 4 is a schematic view showing another mode of cutting and expanding the joining structure of the fishing rod 1 shown in fig. 3 with a line extending in the direction of the central axis X.

As shown in the figure, the fishing rod 1 has a tip rod 2 and a hand rod 5 joined to the tip rod 2. The tip rod 2 and the hand rod 5 are each formed in a hollow tubular shape extending in the central axis X direction. The tip rod 2 extends from its rear end 2a1 to its front end 2a 2. The side hand pole 5 extends from its rear end 5a1 to its front end 5a 2. The tip rod 2 and the hand rod 5 are obtained by, for example, sintering a prepreg obtained by impregnating carbon fibers with a synthetic resin to form a tubular sintered body, and subjecting the sintered body to polishing treatment and coating.

The rear end of the hand rod 5 is provided with a handle 4. The fishing reel seat 3 is arranged in front of the handle 4 of the hand rod 5. A plurality of fishing line guides 7 are attached to the upper ends of the outer peripheral surfaces of the tip rod 2 and the hand rod 5. A reel, not shown, is mounted on the reel seat 3. In the illustrated embodiment, a two-bearing reel is mounted to the reel holder 3. Two-bearing reels are also known as drop wheels (Bait Reel) or road wheels (BaitCast). In the case of a two-bearing reel, the fishing line guide 7 is provided at the upper ends of the outer peripheral surfaces of the tip rod 2 and the side-of-hand rod 5 as shown in the drawing. In other embodiments, the fishing vessel base 3 may also be fitted with a spinning wheel. In the case of using the spinning wheel, the fishing line guide 7 is provided at the lower end of the outer peripheral surfaces of the tip rod 2 and the hand rod 5. In the present specification, when referring to the front-rear direction of the fishing rod 1 or the tip rod 2 and the hand rod 5 constituting the fishing rod 1, the front-rear direction shown in fig. 1 is taken as a reference.

In one embodiment, the hand side rod 5 is configured to have a larger inner diameter than the tip rod 2. The tip rod 2 is an example of a small diameter rod body, and the hand rod 5 is an example of a large diameter rod body. The inner diameter of the hand rod 5 and the inner diameter of the tip rod 2 are, for example, in the range of 3mm to 15mm, and the outer diameters thereof are, for example, in the range of 5mm to 20 mm. The dimensions of the tip rod 2 and the hand rod 5 described in this specification are examples.

The tip rod 2 and the hand rod 5 are detachably connected to each other via a socket joint core 6. The socket joint core material 6 is obtained by, for example, sintering a prepreg obtained by impregnating carbon fibers with a synthetic resin to form a tubular sintered body, and subjecting the sintered body to a polishing treatment and a coating treatment. The socket joint core material 6 has a substantially cylindrical rear end portion 6a, an inclined portion 6b provided on the front side of the rear end portion 6a and having an outer peripheral surface inclined at a first angle θ 1 with respect to the central axis X, and a front end portion 6c provided in front of the inclined portion 6b and having a substantially cylindrical shape. The front end portion 6c is formed to be smaller in diameter than the rear end portion 6 a. The socket joint core material 6 is formed so that the length in the direction of the central axis thereof is 50mm to 150mm, and the outer diameter of the rear end portion 6a thereof is 3mm to 15 mm. A first angle θ 1 formed by the outer peripheral surface of the inclined portion 6b and the central axis X is, for example, in a range of 0.05 ° to 5.0 °. The inclination of the outer peripheral surface of the inclined portion 6b shown in fig. 2 is exaggerated to show the inclination for easy understanding. The socket core material 6 may be hollow or solid. The dimensions and shape of the socket joint core material 6 described in the present specification are examples. For example, the socket joint core member 6 may be configured such that the outer peripheral surface thereof is inclined at a predetermined angle with respect to the central axis X from the rear end to the front end thereof.

In one embodiment, the socket joint core 6 is inserted into the hand side pole 5 to a predetermined position in the direction of the central axis X, and is fixed to the inner circumferential surface 5b of the hand side pole 5 by, for example, adhesion. The socket core member 6 is fixed to the side pole 5 so that a part thereof protrudes forward from the front end 5a2 of the side pole 5. The side pole 5 is in contact with the socket core 6 near its front end. The socket joint core material 6 is an example of a shaft member inserted into the rod body.

When the female joint core member 6 protruding from the front end 5a2 of the side pole 5 is inserted into the peak pole 2 from the rear end 2a1, the female joint core member 6 is inserted into the peak pole 2 to a predetermined positioning position. Thereby, the tip rod 2 and the hand rod 5 are joined via the socket joint core 6.

In fig. 2, the socket joint core material 6 is inserted to a positioning position. When the socket core 6 reaches the set position, a gap is formed between the front end 5a2 of the side pole 5 and the rear end 2a1 of the tip pole 2. The length of the gap in the direction of the central axis X is, for example, 3mm to 10 mm. The dimensions of the gap are exemplary. Since there is a gap between the tip rod 2 and the side rod 5, when the tip rod 2 and the side rod 5 are bent during use of the fishing rod 1, bending stress and shearing stress act on the socket core 6.

In another embodiment, the socket joint core 6 is bonded to the inner peripheral surface 2b of the joint portion 2a of the tip rod 2. In this case, the socket core 6 is fixed to the peak pole 2 so as to project rearward from the rear end 2a1 of the peak pole 2. The hand side rod 5 is inserted into the socket core 6 at a position projecting from the rear end 2a1 of the tip rod 2, whereby the tip rod 2 and the hand side rod 5 are connected via the socket core 6.

Next, the shape of the inner circumferential surface 2b near the rear end 2a1 of the tip rod 2 will be described. The inner circumferential surface 2b of the tip rod 2 has an inclined surface 2b1 inclined with respect to the central axis X direction and extending forward from the rear end 2a1, a stress relaxation surface 2b2 extending from a position P1 to a position P2 of the front end of the inclined surface 2b1, and a cylindrical surface 2b3 extending from a position P2 to a position P3. The position P1 indicates a position shifted forward from the rear end 2a1 of the tip rod 2 along the central axis X by L1, and the position P2 indicates a position shifted forward from the position P1 along the central axis X by L2. The position P3 is an arbitrary position between the position P2 and the front end 2a2 of the tip rod 2 on the central axis X. The length L1 is, for example, a length in the range of 1mm to 30 mm. In one embodiment, length L1 is in the range of 1mm to 5 mm. The length L2 is equal to or less than the length L1. When the stress relaxation surface 2b2 extending forward from the position P1 becomes long (when the length L2 starting from the position P1 becomes long), the ratio of the stress relaxation surface 2b2 occupying the tip rod 2 becomes large. Since the stress relaxation surface 2b2 is thinned, the strength near the rear end of the tip rod 2 may be insufficient when the length L2 is increased. By setting the length L2 to a length equal to or less than the length L1, the strength of the tip rod 2 can be prevented from becoming insufficient. The position P1, the position P2, and the position P3 are examples of a first position, a second position, and a third position, respectively, in the central axis X direction.

The inclined surface 2b1 is inclined at a second angle θ 2 larger than the first angle θ 1 with respect to the central axis X and extends to P1. The second angle θ 2 is, for example, an angle larger than the first angle θ 1. The second angle θ 2 is, for example, in the range of 0.1 ° to 10.0 °. In one embodiment, the second angle θ 2 is 2.0 °. The inclined surfaces 2b1 may be at the same angle at any position in the circumferential direction around the center axis X, or may be at different angles depending on the position in the circumferential direction. For example, the second angle θ 2 of the first position in the circumferential direction₁A second angle theta 2 with a second position rotated by a predetermined angle from the first position in the circumferential direction₂Or may be at different angles. However, the second angle θ 2₁And a second angle theta 2₂Are all larger than the first angle θ 1.

The cylindrical surface 2b3 extends from the position P2 to the position P3 in parallel or substantially parallel to the central axis X direction. When the inclination of the cylindrical surface 2b3 with respect to the direction of the central axis X is smaller than the first angle θ 1, the cylindrical surface 2b3 can be said to extend substantially parallel to the direction of the central axis X. The tip rod 2 is configured to be tapered from the rear end toward the front end. In this case, the outer peripheral surface of the tip rod 2 extends at a predetermined angle to the central axis X direction. The cylindrical surface 2b3 may extend parallel to the outer peripheral surface of the tip rod 2.

The stress relaxation surface 2b2 is a portion between the inclined surface 2b1 and the cylindrical surface 2b3 of the inner peripheral surface 2b of the tip rod 2. The stress relaxation surface 2b2 has inclined portions 21a, 21b, 21c, 21d and a non-inclined portion 22. For convenience of explanation, the inclined portions 21a, 21b, 21c, and 21d may be collectively referred to as the inclined portion 21. The boundary 23a between the inclined portion 21 and the non-inclined portion 18 has a wave shape protruding rearward from the boundary 23b between the inclined surface 2b1 and the stress relaxation surface 2b 2. The boundary 23b extends in the circumferential direction around the central axis X. In the present specification, the boundary 23a is sometimes referred to as a stress relaxation boundary, and the boundary 23b is sometimes referred to as a positioning position boundary.

The inclined portion 21 is continuous with the inclined surface 2b1 at the rear end thereof. That is, the rear end of the inclined portion 21 is at the position P1. The inclined portions 21 extend forward along the central axis X from the positions P1, respectively. The tip ends of the inclined portions 21 may be different from each other. In the illustrated embodiment, as described above, four inclined portions 21a, 21b, 21c, and 21d are provided, and the inclined portion 21a extends to a position P1 as a boundary with the cylindrical surface 2b 3. The inclined portion 21a extends to the forefront among the four inclined portions. The inclined portion 21b, the inclined portion 21c, and the inclined portion 21d extend from the position P1 to a position between the position P1 and the position P2.

The inclined portions 21 are inclined at a second angle θ 2 larger than the first angle θ 1 with respect to the central axis X, similarly to the inclined surfaces 2b1, respectively. The inclined portion 21 may have an angle with respect to the direction of the central axis X that differs depending on the position in the circumferential direction around the central axis X. For example, the angle formed by the inclined portion 21a and the direction of the central axis X may be different from the angle formed by the inclined portion 21b and the direction of the central axis X. Further, the angle formed by the position B1 of the inclined portion 21a in the circumferential direction and the central axis X direction may be different from the angle formed by the position B2 of the inclined portion 21a in the circumferential direction and the central axis X direction. That is, the angle formed by the inclined portion 21a and the central axis X direction may be different depending on the circumferential position. This also applies to the inclined portions 21b, 21c, 21 d. The angle of the inclined portion 21 with respect to the central axis may be the same as or different from the angle of the inclined surface 2b1 with respect to the central axis.

The stress relief surface 2b2 is further described with reference also to fig. 14 and 15. Fig. 14 is a view showing a cross section obtained by cutting the tip rod 2 with a plane perpendicular to the central axis X and passing through the position B1, and fig. 15 is a view showing a cross section obtained by cutting the tip rod 2 with a plane perpendicular to the central axis X and passing through the position C1. The position C1 is located further forward than the position B1 in the direction along the center axis X.

As described above, the inclined portion 21a is inclined at an angle larger than the first angle θ 1 with respect to the central axis X, and the non-inclined portion 18 extends parallel or substantially parallel to the central axis X. Therefore, as shown in the sectional view of fig. 14, the stress relaxation face 2B2 is recessed toward the radially outer side of the tip rod 2 at the inclined portion 21a between the position B1 and the position B2, between the position B3 and the position B4, and between the position B5 and the position B6 in the circumferential direction. Likewise, in the cross section shown in fig. 15, the stress relaxation surface 2b2 is also recessed toward the radially outer side of the tip rod 2 between the position C1 and the position C2 and between the position C3 and the position C4 in the circumferential direction.

When the fishing rod 1 is used, the tip rod 2 is bent downward in fig. 14, and thus a lower portion of the tip rod 2 is compressed. The compressed portion of the tip rod 2 is a portion within a predetermined angular range around the lower end of the tip rod 2. The lower end of the tip rod 2 represents the 0 ° position in figure 13. The compressive force acts in particular on the region of ± 30 ° centered on this 0 ° position. The region of the tip rod 2 in the range of ± 30 ° in the circumferential direction from the lower end is referred to as a compression region R1.

In the illustrated embodiment, the fishing line guide 7 is provided at the upper end of the tip rod 2 (and the hand-side rod 5), and therefore the compressed region R1 is located on the opposite side of the mounting position of the fishing line guide 7 in the circumferential direction around the center axis X. In the explanation with reference to fig. 13, the fishing line guide 7 is provided at a position of 180 ° in the circumferential direction, and the compressed region R1 is located at ± 30 ° with the position of 0 ° as the center. In other embodiments using the spinning wheel, the fishing line guide 7 is provided at a position of 0 ° in the circumferential direction, and therefore the compressed region R1 is provided on the lower side of the tip rod 2 similarly to the fishing line guide 7.

At least one of the inclined portions 21a, 21b, 21c, 21d is provided in the compression region R1. In the illustrated embodiment, the inclined portion 21a is provided in the compression region R1. The inclined portion 21a may be provided entirely in the compression region R1, or may be provided partially in the compression region R1.

Thus, the stress relaxation face 2b2 has the non-inclined portion 18 and the inclined portion 21a recessed from the inclined portion 22 in the radial direction of the tip rod 2. The shape and arrangement of the inclined portion 21a in the stress relaxation surface 2b2 are not limited to those shown in the drawings.

In the illustrated embodiment, a portion of the non-inclined portion 18 extends from position P2 to position P1. In other words, the rear end of a part of the non-inclined portion 18 is located at a position P1 in the central axis X direction. The ratio of the circumferential length (corresponding to the length b1+ b2+ b3+ b4 in fig. 13) of the non-inclined portion 18 at the position P1 in the central axis X direction to the entire circumferential length (corresponding to the length a in fig. 13) of the inner circumferential surface of the stress relaxation surface 2b2 is 0.5 or more. Namely, (b1+ b2+ b3+ b4)/a is 0.5 or more (50% or more in terms of percentage).

As described above, in order to manufacture the tip rod 2 according to the embodiment, a prepreg obtained by impregnating carbon fibers with a synthetic resin is sintered to prepare a tubular sintered body. The inclined surface 2b1 and the stress relaxation surface 2b2 of the pointed rod 2 are obtained by processing the inner peripheral surface of the tubular sintered body using a tool such as a tapered reamer. In one embodiment, the tapered reamer may be inserted into the interior of the tip rod 2 such that the axial direction thereof is slightly inclined with respect to the central axis X (for example, inclined at an angle in the range of 0.05 ° to 2 °) to form the inclined surface 2b1 by cutting the inner peripheral surface of the tip rod 2, and then, a reamer (for example, a pin reamer) having a smaller diameter may be used to cut a region of the inner peripheral surface of the tip rod 2 that is further inside than the inclined surface 2b1, thereby forming the inclined portion 21 a. In another embodiment, the inclined surface 2b1 and the inclined portion 21a may be formed by first cutting the inner peripheral surface of the tip rod 2 using a pin reamer to form a narrow groove corresponding to the inclined portion 21a, and then cutting the inner peripheral surface of the tip rod 2 using a tapered reamer to a shallower extent than the narrow groove. Thus, the inclined surface 2b1 and the stress relaxation surface 2b2 provided with the inclined portion 21a can be formed. The inclined surface 2b1 and the inclined portion 21a may be formed first, or may be formed at one time.

As described above, the socket joint core member 6 may be bonded to the inner peripheral surface 2b of the joint portion 2a of the tip rod 2. In this case, the hand side rod 5 is inserted into the portion of the socket core 6 protruding from the rear end 2a1 of the tip rod 2, whereby the tip rod 2 and the hand side rod 5 are connected via the socket core 6. In this case, the vicinity of the front end of the inner circumferential surface 5b of the hand rod 5 is formed in the same manner as the vicinity of the rear end of the inner circumferential surface 2b of the tip rod 2. Specifically, the vicinity of the tip of the inner peripheral surface 5b of the rod 5 on the side of the hand is formed with an uneven structure corresponding to the inclined surface 2b1 and the stress relaxation surface 2b 2.

The inclined surface 2b1 and the stress relaxation surface 2b2 may be formed near the rear end of the inner peripheral surface of the tip rod 2, and the uneven structure corresponding to the inclined surface 2b1 and the stress relaxation surface 2b2 may be formed near the front end of the inner peripheral surface of the side rod 5. By providing such a concave-convex structure on both the tip rod 2 and the hand rod 5, breakage can be further suppressed. In this case, the socket joint core member 6 may be bonded to the inner peripheral surface of the side pole 5 or may not be bonded to the inner peripheral surface of the tip pole 2.

Next, a fishing rod 101 according to another embodiment of the present invention will be described with reference to fig. 16. Fig. 7 is a sectional view schematically showing a joining structure of a fishing rod 101 according to another embodiment of the present invention.

The fishing rod 101 is a butt-jointed fishing rod. The fishing rod 101 has a hand rod 102 and a tip rod 105 engaged with the tip of the hand rod 102. The tip rod 105 is configured to be smaller in diameter than the hand rod 102. The outer peripheral surface 105a of the tip rod 105 is formed so that the outer diameter at the positioning position substantially matches the inner diameter of the hand rod 102 at the positioning position when the tip rod is inserted into the hand rod 102 to the positioning position. This enables the tip rod 105 to be joined to the hand rod 102. In the embodiment of fig. 16, the rear end of the tip rod 105 (the end on the side close to the hand rod 102) corresponds to a shaft member inserted into the rod body.

The inner circumferential surface 102b of the hand rod 102 is configured in the same manner as the inner circumferential surface 2b of the tip rod 2 shown in fig. 12 to 15. That is, the inner circumferential surface 102b of the rod 102 on the side of the hand is formed to have an uneven structure corresponding to the inclined surface 2b1 and the stress relaxation surface 2b2 in the vicinity of the tip thereof. Although not shown, the outer peripheral surface 105a of the tip rod 105 is provided with an inclined portion similar to the inclined portion 6b of the socket joint core material 6.

Fig. 16 shows only two rods, the hand rod 102 and the tip rod 105, but a fishing rod of the side-by-side type may have three or more rod bodies joined thereto. The rod bodies constituting the parallel-joining type fishing rod can be joined by using the joining structure similar to that of the hand side rod 102 and the tip rod 105.

Next, the operational effects achieved by the above-described embodiment will be described. In the above embodiment, the inner peripheral surface 2b of the tip rod 2 into which the socket joint core 6 is inserted has the inclined surface 2b1, the stress relaxation surface 2b2, and the cylindrical surface 2b3 in the vicinity of the rear end thereof. The stress relaxation surface 2b2 has inclined portions 21a, 21b, 21c, 21d and a non-inclined portion 18. The inclined surface 21 and the inclined portions 21a, 21b, 21c, 21d extend at an inclination angle larger than the inclination angle of the outer peripheral surface of the socket joint core material 6 with respect to the central axis X direction, whereas the non-inclined portion 18 extends parallel or substantially parallel to the central axis X direction. When the socket core 6 is fitted to the inner peripheral surface 2b of the tip rod 2, the inner peripheral surface 2b of the tip rod 2 is in contact with the socket core 6 at the positioning position boundary 23 b. Thus, the tip rod 2 is supported by the socket core 6 at the boundary 23 b.

When the tip rod 2 and the hand rod 5 are flexed during use of the fishing rod 1, the inner peripheral surface 2b of the tip rod 2 is in contact with the socket core 6 not only at the positioning position boundary 23b but also at the stress relaxation boundary 23 a. Since the stress relaxation boundary 23b has a wavy shape protruding toward the rear end side in the central axis X direction, the stress acting on the socket joint core material 6 from the inner peripheral surface 2b of the tip rod 2 acts not only at the position P1 in the central axis X direction where the positioning position boundary 23b is arranged but also at a position shifted rearward in the central axis X direction from the position P1. That is, the stress applied to the socket core 6 from the inner peripheral surface 2b of the tip rod 2 can be dispersed over a wide range in the central axis X direction, rather than being dispersed at one point (position P1) in the central axis X direction. For example, fig. 13 shows a position a, a position B1, a position C1, and a position D existing on the stress relaxation boundary 23a, and the position a, the position B1, the position C1, and the position D are arranged at different positions in the central axis X direction. Before the tip rod 2 is deflected, the inner circumferential surface 2b of the tip rod 2 comes into contact with the socket core 6 at the positioning position boundary 23 b. When the tip rod 2 and the side rod 5 are bent, the stress relaxation boundary 23b comes into contact with the socket core 6 in order from a position close to the positioning position boundary 23 b. In the conventional joint structure, since the structure corresponding to the stress relaxation surface 2b2 is not provided, the stress concentration with respect to the socket core member acts on the rear end of the butt rod 2, which causes the breakage of the socket core member. In contrast, in the above embodiment, the stress relaxation surface 2b2 acts so as to disperse the stress on the socket core 6 in the direction of the central axis X, and therefore, the breakage of the socket core can be suppressed.

In the joining structure of the parallel joining type fishing rod 101 shown in fig. 16, the stress applied to the tip rod 105 from the inner peripheral surface of the rod 102 on the hand side can be dispersed in the central axis direction for the same reason. This can suppress breakage of the tip rod 105.

In the above-described embodiment, the ratio of the circumferential length of the non-inclined portion 18 at the position P1 in the central axis X direction to the total circumferential length of the inner circumferential surface of the stress relaxation surface 2b2 is 0.5 or more. This makes it possible to disperse stress on the socket core 6 or the tip rod 105 in the central axis direction, and to reliably hold the socket core 6 or the tip rod 105 at the position P1 serving as the positioning position.

The above-described operational effects are exerted by the configuration of the compression region R1 existing in the inclined portions 21a, 21b, 21c, 21d, in particular. The structures outside the compression region R1 in the inclined portions 21a, 21b, 21c, 21d may be omitted.

Fig. 17 is a view showing one embodiment of a bell and spigot joint type fishing rod of the present invention.

The fishing rod 1 of the present embodiment is provided with four joint structures of three rods (middle rods 20 and 30 and tip rod 40) which are connected to the front end side of the root rod 10 in sequence in a detachable manner, and the front end of each rod is provided with a joint structure (socket joint) in which a socket joint 80 is fitted and fixed. That is, the back end 21 of the middle rod 20 is fixed in the socket joint 80 fixed on the front end 12 of the root rod 10, the back end 31 of the middle rod 30 is fixed in the socket joint 80 fixed on the front end 22 of the middle rod 20, and the back end 41 of the tip rod 40 is fixed in the socket joint 80 fixed on the front end 32 of the middle rod 30. Therefore, the socket joint 80 is inserted and fixed to the front end of each rod in a manner that the front end of the socket joint is exposed, so that the inner circumference of the opening of the rear end of the rod on the small diameter side can be inserted and fixed.

In the present embodiment, the fishing rod 1 has four joint structures as a whole, but the number of joints is not limited, and a plurality of rods are connected via the socket joint 80 to constitute one fishing rod.

In the following description, the large diameter rod and the small diameter rod refer to the relationship of the rods of the portion connected (joined) to each other via the socket joint 80. Therefore, the middle rod 20 shown in fig. 17 is a rod with a large diameter in the relation with the middle rod 30, and a rod with a small diameter in the relation with the root rod 10.

In the enlarged view of the joint portion described below, the large diameter rod is represented by the middle rod 20, and the small diameter rod is represented by the middle rod 30. That is, in the four joined fishing rods of the present embodiment, since the joining structure of the rods is substantially the same, the joining relationship between the center rod 20 and the center rod 30 is representatively illustrated and described. As shown in fig. 1, the front end (front end side) refers to the tip side of the fishing rod, and the rear end (rear end side) refers to the tail side of the fishing rod.

The fishing rod 1 of the present embodiment has a structure in which the length of the middle rod 20, 30 and the tip rod 40 is shorter than that of the root rod 10. The middle rods 20 and 30 may have the same length, or the tip rod 40 may have a shorter length than the middle rods 20 and 30. Also, it can be constructed such that the length of rod is shortened from the middle rod 20 to the tip rod 40 in sequence. Each of the rods 10, 20, 30, 40 is formed as a tubular member, and as is well known, a prepreg obtained by impregnating a synthetic resin with reinforcing fibers is wound around a core mold, and the synthetic resin is cured by heat treatment and then is formed into a tubular shape by core removal. In this case, the rod rods may be formed in a tubular shape by joining portions thereof via socket joints, and have a solid structure in other portions.

The rod 10 is provided with a fishing reel seat 10A on which a reel is mounted, and handles (a front handle 10B, a rear handle 10C) are provided around the rod, the handles 10B, 10C being formed of a material that realizes light weight and is comfortable to hold, such as a foamed material having flexibility such as EVA, cork, or the like.

The rod rods 20, 30, and 40 are respectively provided with a fishing line guide for inserting a fishing line fed from a reel fixed to the reel seat 10A. Specifically, one fishing line guide 25 is installed to the rod 20, two fishing line guides 35 are installed to the rod 30, and three fishing line guides 45 are installed to the tip rod 40. In addition, the tip rod 40 is mounted with a tip guide 46 at the front end.

Fig. 18 is an enlarged view showing a junction region between a middle rod 20 (hereinafter, referred to as a large diameter rod 20) and a middle rod 30 (hereinafter, referred to as a small diameter rod 30).

The socket 80 is pressed and fixed from the opening side of the front end 22 of the rod 20 with a large diameter, and the outer peripheral surface 81 of the back end side of the socket 80 is adhered and fixed to the inner peripheral surface 22a of the opening of the front end of the rod 20 with a large diameter. The spigot-and-socket joint 80 protrudes from the opening edge 22b of the front end 22 of the large diameter rod 20, and the inner peripheral surface 31a of the opening of the rear end 31 of the small diameter rod 30 is press-fitted and fixed to the outer peripheral surface 82 of the protruding front end side. In this case, the small diameter rod 30 is pressed and fixed between the opening edge 31b of the rear end 31 of the small diameter rod 30 and the opening edge 22b of the front end 22 of the large diameter rod 20 through the gap l, and is not pressed in the entire range of the length direction of the socket joint 80.

The gap l exists in the joint area of all the rods, and the length of the gap l is formed to be substantially the same in all the joint portions.

The socket joint 80 is preferably made of a material that can reduce the weight, and for example, a prepreg obtained by impregnating carbon fibers with a synthetic resin can be used as a tubular (cylindrical) member by sintering. The spigot-and-socket joint 80 may have a uniform outer diameter over the entire length, or may have a conical surface (a conical surface that is fitted into the opening of the rear end of the rod with a small diameter and to which the rod with a small diameter is fixed) that decreases in diameter toward the front end. The socket joint 80 may be formed in a solid shape, or may be formed in a hollow shape for weight reduction as in the present embodiment. The socket joint 80 of the present embodiment is formed, for example, with a length L in the central axis direction of 50 to 150mm, an inner diameter d1 of 2 to 10mm, and an outer diameter d2 of about 3 to 15mm, but this can be changed as appropriate depending on the thickness of the rod constituting the fishing rod and the joining portion. In the case where the conical surface is formed on the outer peripheral surface of the socket joint, the conical surface may be formed only in the joining region with the small diameter rod.

In the fishing rod of the socket joint type as described above, when a fish is hooked at a real time and the whole fishing rod is bent, stress concentration occurs in a part of the outer peripheral surface of the socket joint 80, bending stress and shearing stress act on the part, and there is a problem that the socket joint 80 is broken. This is because the edge 22b 'of the open edge 22b of the front end 22 of the large diameter rod 20 and the edge 31 b' of the open edge 31b of the rear end 31 of the small diameter rod 30 are in contact with the outer peripheral surface of the socket 80 in a circular line when the fishing rod is bent.

In this way, in the joint structure in which the outer peripheral surface of the socket joint is in annular line contact, stress concentration becomes remarkable, and loosening or tightening is easy during mounting, so that it is difficult to achieve appropriate joint. In the present embodiment, as will be described later, the inclined surfaces (conical surfaces) 22A and 31A are formed on the opening inner peripheral surfaces 31A and 22A so as to have a clearance (a small clearance) with respect to the outer peripheral surface of the socket joint, respectively, and the edge 22b 'and the edge 31 b' are not in line contact with each other at right angles with respect to the outer peripheral surface, so that the inner rising position P1 (a position where the inclined surface rises from the outer peripheral surface of the socket joint) is in contact with each other to alleviate stress concentration. That is, by reducing the inclination angle θ 1 from the raised position P1, the stress acting on the outer peripheral surface of the socket joint is relaxed.

Here, the stress relaxation by the inclined surface is described. In addition, since the same phenomenon occurs in the end regions of the large diameter rod and the small diameter rod, the inclined surface 31A on the small diameter rod side will be described here.

As shown in fig. 18, by forming an inclined surface (a conical surface with an inclination angle θ 1 described later) 31A with a diameter gradually increasing from the rising position P1 toward the rear end side at the rear end portion 31 of the small diameter rod 30, it is possible to alleviate the stress concentration caused by the circular line contact. In other words, the inner peripheral surface of the opening of the small diameter rod 30 is provided with an inclined surface 31A inclined at an inclination angle θ 1 with respect to the central axis X of the small diameter rod so as to be reduced in diameter from the opening edge 31b toward the tip end side by a constant axial length L1 and to have a gap (minute gap) between the outer peripheral surfaces 82 of the female joint 80. The inclined surface 31A abuts against the outer peripheral surface 82 of the female joint 80 at the rising position P1 so as to have a slight inclination angle θ 1, whereby an effect of relaxing the pressing force (shear stress) can be obtained in comparison with the abutting state in the right angle direction when the small diameter rod is actually flexed.

In this case, the inclined surface 31A formed at the rear end 31 of the rod 30 with a small diameter may become thinner toward the end, and the strength may be reduced and cracks may be generated, so that the axial length L1 for forming the inclined surface 31A is not appropriate if it is too long. It is preferable that the thickness is at most 10mm or less, and in the range of 5mm or less, preferably 1mm to 3mm, as described in patent document 2, sufficient strength can be secured without thickening the conical region.

In the structure shown in fig. 18, since the outer peripheral surface of the socket 80 is formed in a substantially linear shape extending in the axial direction, the inclination angle θ 1 is shown as an angle with respect to the outer peripheral surface of the socket 80, and actually shows an inclination angle with respect to the central axis X of the small diameter rod.

The inclination angle θ 1 shown in fig. 18 is an important parameter in suppressing damage due to stress concentration, and if it is too large, it does not mean (if only the inclined surface is formed, the edge at the rising position P1 becomes small, and stress cannot be effectively relaxed), and therefore, in practice, the following test is performed as to how much damage due to stress concentration can be suppressed.

Here, a four-point bending test according to JIS K7074 was performed by measuring the bending breaking strength of a test piece in which a small diameter rod and a large diameter rod are joined by a socket joint in the same manner as the joining structure shown in fig. 18.

Fig. 19 is a schematic diagram showing an outline of the four-point bending test.

Both the small diameter rod 130 and the large diameter rod 120 shown in fig. 19 are formed by winding a prepreg obtained by impregnating carbon fiber with a synthetic resin around a mandrel, and sintering and depoling the same according to a conventional method. The inner diameter of the small diameter rod 130 is 8.09mm, the inner diameter of the large diameter rod 120 is 8.20mm, the rear end 131 of the small diameter rod 130 is formed with an inclined surface (inclination angle theta 1) gradually expanding diameter toward the rear end side, and the front end 122 of the large diameter rod 120 is also formed with an inclined surface (inclination angle theta 1) gradually expanding diameter toward the front end side, in the same manner as the structure shown in fig. 18. In this case, the axial length (axial length L1 shown in fig. 18) of the inclined surface is set to 2 mm.

With respect to the small diameter rod 130, seven rod rods having different inclination angles θ 1 (0.1 °, 1.0 °, 1.2 °, 10 °, 15 °, 20 °, 30 °) are prepared, and with respect to the large diameter rod 120, rod rods having different inclination angles θ 1 (0.1 °, 1.0 °, 1.2 °, 10 °, 15 °, 20 °, 30 °) are also prepared, and the small diameter rod and the large diameter rod having the same inclination angle are connected to each other by the socket joint 180.

The socket joint 180 is formed by winding a prepreg obtained by impregnating carbon fiber with synthetic resin on a mandrel, and sintering and depoling the same according to a conventional method, as in the rod. The female joint 180 has an inner diameter of 3.0mm, an outer diameter of 8.0mm at the tip side, and a length of 120 mm. In this case, the outer diameter of the socket 180 is substantially linear in the axial direction, and is fixed near the middle position thereof when the small diameter rod 130 is pressed into the socket 180.

The test apparatus provided with the above test pieces (seven test pieces obtained by connecting a small diameter rod and a large diameter rod by a socket joint) measured the bending rupture strength at a speed of 50 mm/min for each test piece with the interval La between the fulcrums 150 set to 800mm and the interval Lb between the indenters 160 set to 240mm, and the measurement results of fig. 20 were obtained. Fig. 4 is a graph in which the bending rupture strength measured by the four-point bending test is plotted, the horizontal axis represents the inclination angle θ 1 of each test piece, and the vertical axis represents the measured bending rupture strength (bending rupture strength of the socket joint 180).

As is clear from the graph, the bending rupture strength of the socket joint changes by changing the inclination angle θ 1, but as described above, the bending rupture strength decreases when the inclination angle θ 1 exceeds 10 °, and the bending rupture strength also has a substantially constant level when the inclination angle is not less than 15 °. This is considered to be because when the inclination angle θ 1 is large to some extent, a sufficient stress relaxation effect cannot be expected due to a sharp angular change (edge) at the rising position P1 when the rod is bent.

As described above, when the axial length of the inclined surface formed at the rear end 131 of the small diameter rod 130 is set to 2mm, the inclination angle θ 1 at which the bending strength is strong is 10 ° or less, preferably 5 ° or less, and more preferably in the range of 1 ° to 3 ° surrounded by dots. That is, it is considered that when the inclination angle θ 1 exceeds 10 °, the tendency of stress concentration at the rising position of the inclined surface (indicated by P1 in fig. 18) becomes strong and the tendency of breakage becomes strong at the time of rod bending. Further, although stress relaxation can be achieved even if the angle is set to 1 ° or less, if it is too small (0.1 ° or less), it is considered that the edge 31 b' (see fig. 18) of the opening edge of the rear end portion comes into line contact with the outer peripheral surface of the socket, and thus the tendency to damage is considered to be strong.

Therefore, the inclined surface 31A formed on the inner circumference of the opening of the small diameter rod has an inclination angle theta 1 in the range of 1 to 3 degrees relative to the central axis X of the small diameter rod, and the axial length L1 is considered to be formed in the range of 1 to 3mm, so that the opening of the small diameter rod 30 is not damaged, the stress concentration on the outer circumference of the socket joint 80 can be effectively relaxed, and the damage of the socket joint can be effectively prevented. In this case, if the axial length L1 is too long, breakage or the like occurs at the opening edge 31b as described above, and when the thickness of the opening edge 31b is T, the axial length L1 can be made to be less likely to break at the opening portion by converging at about L1 ≦ 10T.

In addition, after the verification by the plurality of test pieces in practice, when the axial length L1 of the inclined surface is set to 2mm, by setting the inclination angle θ 1 to substantially 2 °, a favorable result is obtained that stress concentration with respect to the outer peripheral surface of the socket joint is alleviated and breakage and the like are small. In this case, the inclination angle θ 1 does not need to be formed to be substantially 2 ° over the entire circumference, and may be slightly varied within the circumferential direction as long as it is within the range of 10 ° or less, preferably within the range of 1 ° to 5 °. The inclined surface does not need to be formed over the entire circumference, but may be formed in a certain range (for example, in a range R1 shown in fig. 24 and 25) in which a pressing force acts on the outer circumferential surface of the socket joint when the fishing rod is flexed.

Fig. 21 is an enlarged sectional view of the joining area (inclined surface 31A) of the rod with a small diameter.

As described above, although the stress concentration can be alleviated by setting the inclination angle θ 1 from the rising position P1 to 10 ° or less, preferably 1 ° to 3 °, in such a joining method, the surface of the inclined surface 31A is roughened to form the roughened surface portion 31M. The rough surface portion 31M is formed on the entire surface of the inclined surface 31A in accordance with the ease of processing, but may be formed at least in the vicinity of the raised position P1, and preferably in a region including the raised position P1 that annularly abuts against the outer peripheral surface of the socket joint.

Here, the mode of roughening will be specifically described.

Fig. 22 to 26 are views showing a joining region of a female rod and a small diameter rod, fig. 22 is an enlarged view showing the joining region of the small diameter rod and the female rod, fig. 23 is a schematic view of the joining structure shown in fig. 22 and developed by cutting along a line extending in the direction of the central axis and a sectional view taken along the line a-a of the schematic view, fig. 24 is a sectional view taken along the line B-B of fig. 23, fig. 25 is a sectional view taken along the line C-C of fig. 23, and fig. 26 is a sectional view taken along the rising position P1 of fig. 23 and is a view showing a minute concavo-convex structure. The plurality of minute grooves extending in the axial direction in the circumferential direction and the minute projections and depressions projecting in the radial direction in the circumferential direction correspond to "roughening" in the present embodiment.

As described above, by press-fitting the rear end 31 of the small diameter rod 30 into the socket joint 80, the large diameter rod 20 and the small diameter rod 30 are joined at a predetermined position, and the inclined surface 31A having the inclination angle θ 1 is formed on the opening inner peripheral surface 31A of the rear end 31, whereby the stress concentration with respect to the socket joint portion can be suppressed even if the fishing rod is bent. The rising position P1 is the fitting fixing position between the small diameter rod and the spigot-and-socket joint.

In the example shown in fig. 22, the inclined surface 31A of the small diameter rod is formed in a substantially linear shape on the tip side from the rising position P1, and an inclined surface (conical surface) whose diameter is gradually increased toward the rear end is formed on the outer peripheral surface 82 of the socket 80 (in fig. 22, the inclination angle with respect to the central axis X is denoted by α), so that the small diameter rod 30 can be fixed to the outer peripheral surface of the socket 80 when the small diameter rod 30 is pressed into the outer peripheral surface of the socket 80. If the inclination angle α is smaller than the inclination angle θ 1 of the inclined surface 31A of the rear end 31 of the small diameter rod 30, the small diameter rod 30 can be fixed between the socket joints 80 at a predetermined position during the press-fitting. Specifically, when the inclination angle θ 1 of the inclined surface 31A is set to approximately 2 °, the inclination angle α of the socket joint 80 can be fixed at a predetermined position when the small diameter rod 30 is pushed in, as long as it is about 1 ° or less (in the embodiment, it is set to approximately 0.4 °).

Further, the actual joining is completed at the rising position P1, and from there toward the rear end side, the inclined surface 31A gradually separates from the outer peripheral surface of the socket joint 80 by the above-described inclination angle θ 1, and thereby a gap (minute gap) due to the inclination angle θ 1 is generated between the outer peripheral surfaces of the socket joint 80. The inclined surface 31A can be formed in a bent state in which straight lines intersect at the inclination angle θ 1 at the rising position P1 by high-precision machining, and the fitting and fixing positions can be made with high precision. In this case, it is considered that, when the raised position P1 is not in a bent state where the straight lines intersect, but in a bent state, the accuracy of fitting and fixing positions is slightly deteriorated, but the effect of stress relaxation is increased. In the present embodiment, the rising state of the rising position P1 may have any configuration.

In the configuration shown in fig. 22, it is considered that the small-diameter rod 30 is deflected by the deflection of the fishing rod (the deflection due to the deflection is in the direction of the arrow). As described above, since the inclined surface 31A rising at the inclination angle θ 1 from the rising position P1 is formed on the inner peripheral surface of the rear end 31 of the small diameter rod 30, the edge 31 b' of the opening edge 31b of the rear end 31 does not come into line contact and can come into contact near the rising position P1, thereby suppressing stress concentration and effectively preventing the socket joint 80 from being damaged.

In such a configuration, the rough surface portion 31M shown in fig. 21 is formed in the vicinity of the rising position P1 of the inclined surface 31A, whereby stress concentration can be alleviated. That is, since the inclined surface having the inclination angle α as described above is formed on the outer peripheral surface of the female joint 80, it is considered that the pressure force pressing the outer peripheral surface 82 of the female joint 80 when the small diameter rod is deflected acts in the region near the rising position P1 as the inner peripheral surface of the small diameter rod is separated toward the tip end side with respect to the position closer to the tip end side than the rising position P1.

Therefore, the rough surface portion 31M is formed in a region including the rising position P1 serving as a base point of the inclined surface 31A.

The rough surface portion 31M is formed in the vicinity of the rising position P1, preferably in the inner peripheral surface 31B including the rising position P1 and closer to the tip side than the rising position P1, more preferably in the front and rear regions including (spanning) the rising position P1 and in the axial direction, and by forming such a rough surface portion, the pressing force acting on the outer peripheral surface of the female joint 80 from the inner peripheral surface 31a of the opening of the small diameter rod can be effectively reduced.

Specifically, the rough surface portion 31M is configured such that a plurality of concave portions (fine grooves) 31e, 31f, 31g, and 31h are formed discontinuously in the circumferential direction so as to extend in the axial direction. That is, the inner peripheral surface (non-recessed portion) 31m of the other portion is flat, so that when the small diameter rod is bent, it can be deformed in contact with the outer peripheral surface of the socket joint 80, and the stress can be relaxed.

The shape of the concave portions 31e, 31f, 31g, and 31h is not particularly limited, but as described above, the outer peripheral surface 82 of the female joint 80 is formed with the inclined surface having the inclination angle α that decreases in diameter toward the tip end side, and the inclined surface is separated from the inner peripheral surface 31a of the small-diameter rod toward the tip end, and therefore, it is preferable that each concave portion is inclined so as to become shallower toward the tip end side than the rising position P1. Further, the width of each concave portion is preferably gradually narrowed toward the front end side from the rising position P1.

Further, in the case of considering the deflection of the actual rod having a small diameter, it is preferable that the size of each concave portion is changed in the circumferential direction. That is, when the fishing rod is bent, the lower side (the side enlarged in fig. 18) becomes the compression side, and the upper side becomes the tension side (in fig. 18, the joint portion is bent in a mountain shape). In this case, as shown in fig. 23, when the lowest position in the circumferential direction (the position where the fishing line guide is attached to the fishing rod to which the spinning wheel is attached) is set to the 0 ° position, the fishing rod bends, and the pressing force is applied to the outer peripheral surface of the socket joint substantially in the vicinity of ± 30 ° around the 0 ° position (in fig. 24 and 25, such an arc-shaped range is denoted by reference numeral R1).

Therefore, it is preferable that the recesses 31e and 31h formed in the region where such large deflection occurs be wider than the recesses 31f and 31g at other portions and be formed to be longer in the axial direction. For example, the top D of the concave portion 31e is extended to the axial front end side than the other concave portions, and deformation is allowed even in the vicinity thereof, thereby easily relaxing the stress. That is, when the plurality of recessed portions are formed as described above as the rough surface portion 31M, the size (width, axial length, and the like) of each recessed portion is appropriately set in consideration of the state of deflection when the fishing rod is deflected, whereby the pressing force acting on the outer peripheral surface 82 of the socket 80 can be effectively relaxed without causing a decrease in strength. In this case, if a plurality of recesses are formed in the circumferential direction at the raised position P1, the strength is reduced when the groove width in the circumferential direction at the raised position P1 of each recess is too wide, and therefore the circumferential length (in fig. 23, a1+ a2+ a3+ a4) obtained by summing the non-recesses 31m is preferably secured to be 50% or more of the circumferential length a at that position.

If the size of the recess is too large, the strength is reduced. The size of the recess varies depending on the diameter of the rod having a small diameter, but the groove width, depth, and axial length thereof may be 5 μm or less, preferably 1 to 3 μm, whereby stress concentration can be effectively alleviated without reducing the strength.

The rough surface portion 31M may be formed of fine irregularities 31h protruding in the radial direction in the circumferential direction (continuously formed over the entire circumference of 360 ° in the present embodiment) as shown in fig. 26, in addition to the plurality of recesses along the axial direction. The fine irregularities 31h may be formed over the entire surface of the inclined surface 31A, but may be formed in the vicinity of the raised position P1, preferably in a position including the raised position P1. In addition, such a rough surface portion may be formed to have an uneven height of about 0.5 to 5 μm, and by forming a rough surface portion including such minute unevenness 31h, when the small diameter rod is flexed and bending stress acts on the joining region of the socket joint 80, the large convex portion of the uneven portion is deformed (crushed) and comes into contact with the outer peripheral surface of the socket joint 80, so that the stress can be effectively relaxed.

In addition, the rough surface portion 31M may be formed with any one of the above-described concave portions (fine grooves) and fine irregularities, but by having both structures, stress can be more effectively relaxed. Further, by forming the above-described rough surface portion 31M in the vicinity of the rising position P1, when the small diameter rod 30 is fitted into the socket joint 80, the minute concave-convex portion is deformed in the fixed region, and therefore, the appropriate positioning can be performed, and the accurate positioning can be performed. That is, the spigot portion (portion shown by length l in fig. 18) exposed between the rods to be joined can easily be made substantially uniform in length in all the joined portions, and the appearance can be improved.

Fig. 27 is a cross-sectional view showing a modification of the rough surface portion.

The rough surface portion 31M' of the present embodiment is formed by continuously forming a plurality of minute grooves 31k extending in the axial direction over the entire circumference of 360 °. The plurality of fine grooves 31k are formed randomly in the axial direction in the vicinity of the rising position P1, and include fine grooves extending from the rising position P1 toward the tip end side, fine grooves extending from the rising position P1 toward the rear end side, fine grooves formed across the rising position P1, and the like, and the groove width, depth, and length are formed unevenly.

With this structure, the concentration of stress can be effectively relaxed even when the small diameter rod 30 is bent.

The rough surface portions 31M and 31M' as described above can be formed at the time of rod forming by roughening the corresponding surface region of the core mold (core rod) at the time of forming the tubular small diameter rod 30. Alternatively, the rod may be formed by sand blasting after molding the rod, or may be formed by inserting a processing tool (a tapered reamer, a pin reamer, etc.) into the opening portion, or may be formed by appropriately combining the above methods. In this case, the roughness of the surface of the processing tool may be formed by a plurality of steps by appropriately changing the depth, length, width, and height of the irregularities by changing the contact method or the like. The rough surface portion as described above may be covered with a film having water repellency or water repellency as necessary.

While the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible.

In the present embodiment, the rising position P1 is formed inside the rod with small diameter, but the position is not limited. Therefore, the rear end edge of the small diameter rod can be processed with the rough surface without forming the inclined surface. The inclined surface 31A shown in the present embodiment is formed of a single surface gradually expanding toward the rear end, but may be formed of a plurality of surfaces, or may include a curved surface. Further, the rising position P1 may be present at a plurality of positions on the inner circumferential surface of the small diameter rod.

Further, although the inclined surface 31A as described above has been described by taking a rod with a small diameter as an example, it is preferable that the inclined surface is formed similarly on the opening inner surface of the tip end portion 32 of the rod 30 with a large diameter. Further, the structure for alleviating the stress concentration can be applied to a parallel-type joint portion.

That is, in the parallel-joined type fishing rod, the rear end portion of the small diameter rod is press-fitted into the inner peripheral surface of the opening on the front end side of the large diameter rod, but the same rising position as in the above embodiment may be formed on the inner peripheral surface of the opening on the front end side of the large diameter rod, and a rough surface portion having a plurality of fine recesses and protrusions protruding in the radial direction in the circumferential direction and/or a plurality of fine grooves extending in the axial direction in the circumferential direction may be formed in this region.

In this case, when a rising position is formed inside the inner peripheral surface of the opening on the front end side of the rod with a large diameter, the inner peripheral surface of the opening is expanded in diameter from the rising position toward the front end side by a certain axial length, and is provided with an inclined surface inclined with respect to the central axis of the rod with a small diameter so as to have a gap with the outer peripheral surface on the rear end side of the rod with a small diameter. The rising position is a position where the inclined surface abuts against the outer peripheral surface of the rear end side of the small diameter rod, but the rough surface portion is preferably formed to include the rising position, as in the case of the aforementioned spigot-and-socket joint type fishing rod. In addition, if the inclined surface is formed on the inner peripheral surface of the opening at the front end side of the rod with large diameter, the rough surface part can be formed on the whole surface of the inclined surface for easy processing.

The dimensions, materials, and arrangements of the respective constituent elements described in the present specification are not limited to those explicitly described in the embodiments, and the respective constituent elements may be modified to have any dimensions, materials, and arrangements that can be included in the scope of the present invention. Note that, components not explicitly described in the present specification may be added to the embodiments described above, or a part of the components described in each embodiment may be omitted.

Description of the reference symbols

1. 101: a fishing rod; 2. 105: a tip rod; 2b 1: an inclined surface; 2b 2: a stress relieving surface; 2b 3: a cylindrical surface; 5. 102: a rod on the hand side; 6: a socket joint core material; 10: a root rod; 18: a non-inclined portion; 20. 30: a middle rod; 21: a stress relaxation layer; 21A 1: an inclined surface; 21A 2: a parallel plane; 21a, 21b, 21c, 21 d: an inclined portion; 22: a main body protective layer; 23: a body layer; 24: a protective layer; 31A: an inclined surface; 40: a tip rod; 80: a socket joint; 121a, 121b, 121c, 121 d: an inclined portion; 122: a non-inclined portion; p1: a raised position.