阅读说明：本技术 扁平导线的连接结构及连接方法 (Connection structure and connection method of flat wire ) 是由 驹﨑亘 中村千男人 高桥圭介 上田幸平 于 2021-05-11 设计创作，主要内容包括：本发明提供一种将具有筒状部的连接部件和扁平导线连接的扁平导线的连接结构。在该连接结构中,扁平导线的一端部形成为沿着扁平导线的长度方向对折的形状,且形成为具有比对折前的一端部的宽度小的宽度的板状,该扁平导线的一端部被收纳于筒状部的中空部,该扁平导线的一端部在通过对折而彼此朝向相反方向的一对板状面的至少一者与筒状部的内壁面接触的状态下压接于筒状部。根据本发明的一实施方式的连接方法,能够抑制扁平线和连接部件的接触阻力的偏差。(The invention provides a connection structure of a flat wire for connecting a connection member having a cylindrical portion and the flat wire. In this connection structure, one end portion of the flat wire is formed in a shape folded in two along a longitudinal direction of the flat wire and is formed in a plate shape having a width smaller than that of the one end portion before folding, the one end portion of the flat wire is housed in the hollow portion of the cylindrical portion, and the one end portion of the flat wire is pressed against the cylindrical portion in a state where at least one of a pair of plate-shaped surfaces facing opposite directions to each other by being folded in two is in contact with an inner wall surface of the cylindrical portion. According to the connection method of one embodiment of the present invention, variation in contact resistance between the flat wire and the connection member can be suppressed.)

1. A connecting structure of a flat wire for connecting a connecting member having a cylindrical portion and the flat wire, characterized in that:

one end portion of the flat wire is formed in a shape folded in half along a longitudinal direction of the flat wire and is formed in a plate shape having a width smaller than a width of the one end portion before folding,

one end portion of the flat wire is received in the hollow portion of the cylindrical portion,

one end portion of the flat conductive wire is pressed against the cylindrical portion in a state where at least one of a pair of plate-shaped surfaces, which are oppositely oriented to each other by being folded in two, is in contact with an inner wall surface of the cylindrical portion.

2. The flat wire connecting structure according to claim 1, wherein:

one end portion of the flat conductive wire is bent by 180 degrees along the longitudinal direction at the center in the width direction of the flat conductive wire, and is formed in a plate shape having a width smaller than the width of the one end portion before the bending.

3. The flat wire connecting structure according to claim 1, wherein:

at least one of the plate-shaped surfaces is in surface-to-surface contact with the inner wall surface of the cylindrical portion.

4. The flat wire connecting structure according to claim 1, wherein:

the flat wire is covered with an insulating coating on the surface except for the plate-like surface.

5. The flat wire connecting structure according to claim 1, wherein:

further comprising a lead wire housed in a hollow portion of the cylindrical portion in a state of overlapping the one end portion in a pressure-contact direction of the cylindrical portion,

the lead wire is pressed against the cylindrical portion, and is held in close contact with one of the pair of plate-shaped surfaces and an inner wall surface of the cylindrical portion.

6. The flat wire connection structure according to any one of claims 1 to 5, wherein:

the flat wire has a width larger than an inner diameter of the cylindrical portion.

7. A method of connecting a flat wire by connecting a connecting member having a cylindrical portion and the flat wire, comprising:

a bending step of folding one end portion of the flat wire in two along a longitudinal direction of the flat wire to form the one end portion into a plate shape having a width smaller than a width of the one end portion before folding;

an insertion step of inserting one end portion of the flat conductive wire formed in the plate shape into a hollow portion of the cylindrical portion; and

and a pressure bonding step of pressure bonding the one end portion of the flat conductive wire inserted into the hollow portion to the cylindrical portion in a state where at least one of a pair of plate-shaped surfaces facing opposite directions to each other by being folded in two is in contact with an inner wall surface of the cylindrical portion.

8. The method of connecting flat wires according to claim 7, wherein:

the bending process includes:

a first bending step of bending one end portion of the flat wire to a first angle along a longitudinal direction of the flat wire; and

and a second bending step of bending the one end portion of the flat conductive wire bent to the first angle to a second angle larger than the first angle along the longitudinal direction of the flat conductive wire, thereby forming the one end portion of the flat conductive wire into a plate shape having a width smaller than a width of the one end portion before being bent to the first angle.

9. The method of connecting flat wires according to claim 7, wherein:

in the above-mentioned pressure-bonding step,

the plate-like surface is brought into surface-to-surface contact with the inner wall surface of the cylindrical portion.

10. The method for connecting a flat wire according to any one of claims 7 to 9, wherein:

further comprising a removing step of removing the insulating coating on one surface of the insulating coating covering one end of the flat wire before the bending step,

in the above-mentioned bending process, the bending step,

one end portion of the flat conductive wire is folded in half along the longitudinal direction of the flat conductive wire so that the removed surface faces outward.

Technical Field

The invention relates to a connecting structure and a connecting method of a flat wire.

Background

As a method of connecting the flat wire to the connecting member, a connecting method by crimping is known. For example, japanese patent application laid-open No. 2004-. In the connection method described in patent document 1, first, an end portion of a flat wire is bent into a V-shape, and a cylindrical connection tube portion (cylindrical portion) included in a connection member is inserted. Then, the entire cylindrical portion is crushed, whereby the flat lead is pressed between the cylindrical portions. By bending the flat conductive wire in advance in this manner, a flat conductive wire having a width larger than the inner diameter of the cylindrical portion can be used.

Disclosure of Invention

Problems to be solved by the invention

As shown in fig. 2(a) of patent document 1, the cross-section of the bent flat conductive wire perpendicular to the central axis of the cylindrical portion has a substantially V-shape. When the cylindrical portion is pressed, the corners at both ends of the V-shape are pressed into the inner wall of the cylindrical portion, and the cylindrical portion is deformed. The contact area and the contact pressure between the flat wire and the cylindrical portion vary depending on the degree of deformation at this time, and therefore, the contact resistance between the flat wire and the cylindrical portion varies (in this specification, "variation" means variation per product).

The present invention has been made in view of the above circumstances, and an object thereof is to provide a connection structure and a connection method of a flat conductive wire, which can suppress variation in contact resistance between the flat conductive wire and a member such as a cylindrical portion.

Means for solving the problems

A connection structure according to an embodiment of the present invention is a connection structure of a flat wire connecting a connection member having a cylindrical portion and the flat wire. In this connection structure, one end portion of the flat wire is formed in a shape folded in two along the longitudinal direction of the flat wire, and is formed in a plate shape having a width smaller than the width of the one end portion before folding. The one end portion is housed in a hollow portion of the cylindrical portion, and is pressed against the cylindrical portion in a state where at least one of a pair of plate-shaped surfaces (connection surfaces) that are oppositely oriented to each other by being folded in two is in contact with an inner wall surface of the cylindrical portion.

In this connection structure, the plate-like surface of the one end portion of the flat conductive wire is in contact with the inner wall surface of the cylindrical portion, and therefore, the one end portion of the flat conductive wire and the cylindrical portion are in contact with each other over a large area. Therefore, when the cylindrical portion is pressed against the flat wire, a local force is not easily applied to the inner wall of the cylindrical portion from the one end portion of the flat wire, and the deformed shape of the cylindrical portion is prevented from being deviated. Since the deformed shape of the cylindrical portion can be suppressed from varying, variations in contact area and contact pressure between the flat conductive wire and the cylindrical portion are suppressed, and variations in contact resistance between these components are suppressed.

The one end portion folded in two is formed in a shape in which two plate-like portions having a small width are overlapped with a small gap therebetween by springback of the folded portion. The one end portion is crushed by pressure-bonding such that the plate-like surface of the one end portion having such a shape comes into contact with the inner wall surface of the cylindrical portion, and a restoring force of the one end portion (i.e., a force to restore the two plate-like portions to a shape in which a small gap is left between the two plate-like portions) and a residual stress caused by plastic deformation of the cylindrical portion after pressure-bonding act in directions opposite to each other in the cylindrical portion. Thus, for example, compared to a structure in which the one end portion that is not folded in two is pressure-bonded in the cylindrical portion, a high contact pressure can be obtained in substantially the entire region of the portion where the flat lead and the cylindrical portion are in contact. In addition, the flat wire is in a state compressed by crimping. The restoring force based on the compressed state also acts in the opposite direction to the residual stress. In addition to the restoring force by the spring back, the restoring force generated in the compressed state acts in the opposite direction to the residual stress, and therefore a higher contact pressure is obtained over substantially the entire range of the portion where the flat conductive wire and the cylindrical portion are in contact. Further, by folding in two, the one end portion of the flat conductive wire, which is actually increased in thickness, is inserted into the cylindrical portion, with the result that the gap in the cylindrical portion is suppressed to be small. By suppressing the gap in the cylindrical portion to be small, the force at the time of crimping can be firmly applied to the one end portion, and the one end portion can be sufficiently deformed. In other words, a sufficient restoring force can be generated at one end. This also contributes to obtaining a high contact pressure over substantially the entire area of the portion where the flat conductive wire and the cylindrical portion are in contact.

In one embodiment of the present invention, the one end portion of the flat conductive wire is formed in a shape bent by 180 degrees along the longitudinal direction of the flat conductive wire at the center in the width direction of the flat conductive wire, for example, and is formed in a plate shape having a width smaller than the width of the one end portion before the bending. In this case, for example, the flat conductive wire having a larger width can be housed in the hollow portion of the cylindrical portion (from another viewpoint, the flat conductive wire can be housed in the hollow portion of the cylindrical portion having a smaller inner diameter) as compared with the structure described in patent document 1.

In one embodiment of the present invention, the plate-like surface of the one end portion of the flat conductive wire and the inner wall surface of the cylindrical portion may be in surface contact with each other. At this time, since the contact area between the flat conductive wire and the cylindrical portion is large, the contact resistance between these components is suppressed to be smaller.

In one embodiment of the present invention, the flat wire may be covered with an insulating coating on a surface other than the plate-like surface.

The connection structure according to an embodiment of the present invention may be configured as follows: the lead wire is accommodated in the hollow portion of the cylindrical portion in a state of overlapping with one end portion in the pressure-contact direction of the cylindrical portion. The lead wire is, for example, pressed against the cylindrical portion, and is held in close contact with one of the pair of plate-shaped surfaces and the inner wall surface of the cylindrical portion.

In one embodiment of the present invention, the width of the flat wire may be larger than the inner diameter of the cylindrical portion, for example.

A connection method according to an embodiment of the present invention is a connection method of a flat wire for connecting a connection member having a cylindrical portion and the flat wire, including: a bending step of folding one end portion of the flat wire in two along a longitudinal direction of the flat wire to form the one end portion into a plate shape having a width smaller than a width of the one end portion before folding; an insertion step of inserting one end portion of a flat conductive wire formed in a plate shape into a hollow portion of the cylindrical portion; and a pressure bonding step of pressure bonding the one end portion of the flat conductive wire inserted into the hollow portion to the cylindrical portion in a state where at least one of a pair of plate-shaped surfaces (connection surfaces) facing in opposite directions to each other by being folded in two is in contact with an inner wall surface of the cylindrical portion.

In one embodiment of the present invention, the bending step may include: a first bending step of bending one end portion of the flat wire to a first angle along a longitudinal direction of the flat wire; and a second bending step of bending the one end portion of the flat conductive wire bent to the first angle to a second angle larger than the first angle along the longitudinal direction of the flat conductive wire, thereby forming the one end portion of the flat conductive wire into a plate shape having a width smaller than a width of the one end portion before being bent to the first angle. By bending one end portion of the flat conductive wire in two stages, it is possible to prevent breakage of the bent portion and to easily and appropriately bend the one end portion of the flat conductive wire.

In the crimping step, the plate-like surface of the one end portion of the flat conductive wire may be brought into surface-to-surface contact with the inner wall surface of the cylindrical portion.

The connection method according to an embodiment of the present invention may further include a removing step of removing the insulating coating covering one surface of the insulating coating at the one end portion of the flat wire before the bending step. In this case, in the bending step, one end portion of the flat conductive wire is folded in two along the longitudinal direction of the flat conductive wire so that the removed surface faces outward. Thus, the one end portion of the flat wire is in a state where the insulating coating is not present on both surfaces (a pair of plate-shaped surfaces) facing the member such as the cylindrical portion. Therefore, by applying the removal step and the bending step, even when only one surface of the insulating film can be removed by one removal step, the removal step may be performed only once from the viewpoint of equipment.

Effects of the invention

According to an embodiment of the present invention, it is possible to provide a connection structure and a connection method of a flat conductive wire capable of suppressing variation in contact resistance between the flat conductive wire and a member such as a cylindrical portion.

Drawings

Fig. 1A is a diagram showing a state before a flat wire and a round wire are pressure-bonded to each other in an embodiment of the present invention.

Fig. 1B is a diagram showing a state before the flat wire and the round wire are pressure-bonded to each other in the embodiment of the present invention.

Fig. 1C is a diagram showing a state in which an end portion of a flat wire is inserted into a sleeve in one embodiment of the present invention.

Fig. 1D is a diagram showing a state in which a flat wire and a round wire are crimped to a sleeve in one embodiment of the present invention.

Fig. 2A is a diagram showing a state before the flat conductive wire is subjected to the first-stage bending process in the embodiment of the present invention.

Fig. 2B is a diagram showing a state in which the flat conductive wire is subjected to the first-stage bending process in the embodiment of the present invention.

Fig. 2C is a view showing a state in which the flat conductive wire is subjected to the first-stage bending process in the embodiment of the present invention.

Fig. 3A is a cross-sectional view showing a state before a first stage of bending processing is performed on a flat wire in an embodiment of the present invention.

Fig. 3B is a cross-sectional view showing a state in which a first stage of bending processing is performed on a flat wire in one embodiment of the present invention.

Fig. 3C is a cross-sectional view showing a state in which a flat wire is subjected to a first-stage bending process in one embodiment of the present invention.

Fig. 4A is a diagram showing a state before the flat wire and the round wire are pressure-bonded in one embodiment of the present invention.

Fig. 4B is a diagram showing a state in which a flat wire and a round wire are crimped in one embodiment of the present invention.

Fig. 5A is a diagram showing a flat wire before one end portion is folded in two in one embodiment of the present invention.

Fig. 5B is a diagram showing a flat wire having one end portion folded in two in one embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are examples of a connection structure in the case of pressure-bonding a flat wire and a round wire (cylindrical wire) using a sleeve.

Fig. 1A to 1D are diagrams illustrating a step of pressure-bonding and connecting a flat conductive wire 10 and a round wire 21, which is a conductor of a covered wire 20, by using a sleeve 30, which is a cylindrical portion. In the following description, the thickness direction of the flat wire 10 is defined as the X-axis direction, the width direction of the flat wire 10 is defined as the Y-axis direction, and the longitudinal direction of the flat wire 10 is defined as the Z-axis direction. The X-axis, Y-axis and Z-axis directions are mutually orthogonal. The X-axis direction is also referred to as the vertical direction, the Y-axis direction is also referred to as the horizontal direction, and the Z-axis direction is also referred to as the front-rear direction. Note that the designations of these directions (front-back, left-right, and up-down directions) are used for convenience in explaining the relative positional relationship of the components, and do not indicate absolute directions. That is, the X-axis direction (vertical direction) is not limited to the vertical direction, and may be, for example, a horizontal direction.

Fig. 1A shows a state before the flat wire 10 and the round wire 21 are pressure-contacted. The sleeve 30 has a cylindrical shape before the flat conductive wire 10 and the round wire 21 are connected by pressure contact. The sleeve 30 is formed of a material that can be deformed by application of an external force. The sleeve 30 is made of a metal material such as copper or aluminum.

The flat wire 10 has an elongated thin plate shape. The flat wire 10 is formed of a metal material having conductivity such as copper or aluminum.

The round wire 21 is formed of a conductive metal material such as copper or aluminum, and the periphery other than the end portions is covered with an insulating material (e.g., a resin material). The round wire 21 may be a single wire, or may be a twisted wire obtained by twisting a plurality of thin wires.

The width of the flat wire 10 is larger than the inner diameter of the sleeve 30. Therefore, the flat wire 10 cannot be inserted into the sleeve 30 (i.e., the hollow portion 31 of the sleeve 30) as it is. In the present embodiment, as shown in fig. 1B, the flat wire 10 is bent so that the end portion (one end portion of the flat wire) thereof can be inserted into the hollow portion 31 of the sleeve 30 (see reference numeral 110). The present invention is also applicable to connection of a flat wire having a width smaller than the inner diameter of the sleeve 30.

In the present embodiment, the flat wire 10 is subjected to two-stage bending processing. Generally, the flat conductive wire 10 is subjected to a first-stage bending process using a jig, and then to a second-stage bending process using a tool such as flat-nose pliers or vice or a jig having a function equivalent to that of the former.

Fig. 2A to 2C are views showing a first step of bending by using the jig 100. Fig. 2A shows the flat wire 10 before being bent. Fig. 2B shows a state in which the flat wire 10 is being bent. Fig. 2C shows a state in which the flat wire 10 is bent.

Fig. 3A to 3C are sectional views showing a first stage of the bending process using the jig 100. Fig. 3A shows the flat wire 10 before being bent. Fig. 3B shows a state in which the flat wire 10 is being bent. Fig. 3C shows a state in which the flat wire 10 is bent.

The jig 100 has a female mold part 50 and a male mold part 60 that clamps the flat wire 10 with the female mold part 50. In the die part 50, a groove 51 extending in the Z-axis direction is formed in an upper surface 50a thereof.

The groove 51 has a square groove 54 extending in the Z-axis direction and a V groove 55 extending in the Z-axis direction. The V-groove 55 is formed below the square groove 54. The V-groove 55 is formed below the square groove 54, and the bottom surface of the square groove 54 is separated into a pair of support surfaces 54 a. The pair of support surfaces 54a are flat surfaces recessed downward by one step from the upper surface 50a of the die part 50, are formed adjacent to the respective upper ends of the V-groove 55 in the Y-axis direction, and are separated from each other in the Y-axis direction with the V-groove 55 therebetween. Both ends in the width direction of the end portion 11 of the flat wire 10 are placed on the pair of support surfaces 54 a.

The square groove 54 has a pair of stepped surfaces 54b connecting the upper surface 50a and the support surface 54 a. The distance in the Y-axis direction between the pair of oppositely disposed stepped surfaces 54b is slightly larger than the width of the flat wire 10. In addition, the depth of the supporting surface 54a with respect to the upper surface 50a (in other words, the step difference between the upper surface 50a and the supporting surface 54 a) is almost the same as the thickness of the flat wire 10. Therefore, when both ends in the width direction of the end portion 11 of the flat conductive wire 10 are placed on the pair of supporting surfaces 54a, the end portion 11 is fitted into the groove 51 on the supporting surfaces 54 a.

Further, one end of the groove 51 in the Z-axis direction is blocked by the wall 52, and the other end 53 is not blocked. Therefore, when the end portion 11 of the flat wire 10 is fitted into the groove 51, the portion of the flat wire 10 other than the end portion 11 protrudes from the other end 53 of the groove 51 in the Z-axis direction to the outside of the groove 51. Further, the groove 51 is longer than the sleeve 30 in the Z-axis direction.

By fitting the end portion 11 of the flat wire 10 into the groove 51 and making contact with the wall 52, the position of the end portion 11 in each direction of the X axis, the Y axis, and the Z axis of the jig 100 can be determined.

The V-groove 55 is formed over the entire length of the groove 51 in the Z-axis direction. The V-groove 55 has a pair of forming surfaces 55 a. The pair of molding surfaces 55a form V grooves extending in the Z-axis direction at a V-shape angle of 90 degrees, and form molding surfaces having a V-shape in the cross-sectional shape of the XY plane (plane parallel to the X-axis and the Y-axis). Furthermore, the method is simple. The angle of the V-groove 55 may also be less than 90 degrees.

The boundary portion between the support surface 54a and the forming surface 55a (hereinafter referred to as "corner portion 55 c") is subjected to R-chamfering (round-chamfering). Therefore, when the flat wire 10 is fitted into the groove 51, the flat wire 10 can be prevented from being damaged due to contact with the corner portion 55 c. In addition, when the end portion 11 of the flat conductive wire 10 is bent, the deformation of the end portion (the vicinity of the corner portion 55 c) concentrated on the processing portion can be alleviated, and the flat conductive wire 10 can be prevented from being cracked.

The male mold part 60 has a male part 61 for pressing the flat wire 10 into the V-groove 55. The length of the projection 61 in the Z-axis direction is substantially the same as the length of the groove 51 in the Z-axis direction. The cross-sectional shape of the XY plane of the projection 61 is tapered along the entire length in the Z-axis direction.

The convex portion 61 has a pair of forming surfaces 61a forming a V shape. The pair of molding surfaces 61a form convex portions extending in the Z-axis direction and having a V-shape angle of 90 degrees, and form convex molding surfaces having a V-shaped cross-sectional shape with a tapered tip. The angle of the V-shape of the convex portion 61 is the same as the angle of the V-shape of the V-groove 55. Therefore, in the present embodiment, the angle of the V-shape of the convex portion 61 is 90 degrees.

For convenience of explanation, the lowermost end of the V-groove 55 (specifically, the boundary line between the pair of molding surfaces 55a extending in the Z-axis direction) is referred to as "line 55 b". For convenience of explanation, the leading end of the projection 61 (specifically, the boundary line between the pair of molding surfaces 61a extending in the Z-axis direction) is referred to as a "line 61 b".

The convex portion 61 of the male mold portion 60 descends from above the end portion 11 of the flat wire 10 fitted into the groove 51 toward the end portion 11, and is pressed against the end portion 11. Here, the die part 50 is plane-symmetric with respect to the XZ plane including the line 55b, and the punch part 60 is plane-symmetric with respect to the XZ plane including the line 61 b. When the V-shape formed by the convex portion 61 is aligned with the V-shape formed by the V-groove 55, the line 55b and the line 61b reach the intermediate position in the Y-axis direction of the pair of step surfaces 54 b. Therefore, when the end portion 11 is fitted into the groove 51, the foremost end of the convex portion 61 (i.e., the line 61b) reaches substantially directly above the center line L (see fig. 1A) before the flat conductive wire 10 is processed, and the lowermost end of the V-groove 55 (i.e., the line 55b) reaches substantially directly below the center line L. Therefore, when the punch portion 60 is pressed against the end portion 11, as shown in fig. 2B and 3B, the end portion 11 is sandwiched between the pair of forming surfaces 55a and the pair of forming surfaces 61a, and is bent in a V shape along the center line L.

In the present embodiment, the pair of molding surfaces 55a are formed in a concave V-shape forming an angle of 90 degrees, and the pair of molding surfaces 61a are formed in a convex V-shape forming an angle of 90 degrees. Therefore, when the punch portion 60 is pressed against the end portion 11 of the flat conductive wire 10, the convex portion 61 and the end portion 11, and the end portion 11 and the V-groove 55 are in contact with each other substantially without a gap (i.e., the end portion 11 is sandwiched between the pair of forming surfaces 55a and the pair of forming surfaces 61 a), and the end portion 11 is bent into a V-shape that is opened by 90 degrees.

Further, the dimensions of the forming surface 55a and the forming surface 61a are longer than the dimension of the sleeve 30 in the Z-axis direction. Therefore, the length of the end 11 of the flat conductive wire 10 after bending in the Z-axis direction is also longer than the length of the sleeve 30 in the Z-axis direction.

When the male mold portion 60 is pulled away from the flat wire 10, as shown in fig. 2C and 3C, the end portion 11 of the flat wire 10 is held in a state of being bent in a V shape along the center line L extending in the Z-axis direction.

When the end portion 11 of the flat wire 10 is inserted into the sleeve 30 and pressure-bonded at this stage, a part of the end portion 11 (specifically, both end portions of the V-shaped periphery) is pressed into the inner wall of the sleeve 30, and the sleeve 30 is deformed. Since the contact area and the contact pressure between the end portion 11 and the sleeve 30 vary depending on the degree of deformation at this time, the contact resistance between the end portion 11 and the sleeve 30 is likely to vary.

Therefore, in the present embodiment, the second-stage bending process is performed using a tool such as flat-nose pliers or vice or a jig having a function equivalent to that of the flat-nose pliers or vice. By the bending processing in the second stage, the end portion 11 of the flat wire 10 is folded in half along the center line L in the longitudinal direction of the flat wire 10 with a crease by the processing in the first stage. More specifically, the end portion 11 is bent 180 degrees along the center line L (see fig. 1A). As shown in fig. 1B, the end of the flat wire 10 is formed into a plate shape (see reference numeral 110) that is flatly spread on the XZ plane orthogonal to the Y axis by the second-stage bending process.

For convenience of explanation, the end portion 11 after the two-stage bending process is referred to as a "processed end portion 110". The flat outer surface of the machined rear end portion 110 that extends in the XZ plane is referred to as a "plate-like surface" (or "connecting surface"). The "plate-like surface" is an abbreviation of "surface of plate-like end portion". Note that a plate-shaped surface recognizable in fig. 1B is referred to as "plate-shaped surface 110B", and a plate-shaped surface not visible in fig. 1B, which is a surface opposite to plate-shaped surface 110B, is referred to as "plate-shaped surface 110 a". The plate-like surfaces 110b and 110a (connection surfaces) are brought into contact with the inner wall surface of the sleeve 30 or the outer peripheral surface of the round wire 21 after the press-fitting, whereby the flat wire 10 is electrically connected to the sleeve 30 and the round wire 21.

Further, a method of folding the end portion 11 of the flat wire 10 in two by a single-stage bending process using a tool such as flat-nose pliers or vice or a jig having a function equivalent to these tools also belongs to the scope of the present invention.

However, if the end portion 11 of the flat wire 10 is bent 180 degrees in one step, a large load is applied to the bent portion, and the end portion 11 may be broken at the bent portion. In addition, in a state where the end portion 11 is not bent at all, it is difficult to apply a laterally symmetric external force to the end portion 11 from both ends in the width direction, and therefore, the end portion 11 may not be properly bent (in other words, the end portion 11 is bent along the center line L). In a state where the end portion 11 is not bent properly, the dimension of the end portion 11 in the X-axis direction and the Y-axis direction may not be smaller than the inner diameter of the sleeve 30, and the end portion 11 may not be inserted into the sleeve 30.

In the present embodiment, in order to avoid the above-described problem that may occur when the flat wire 10 is folded in two by the one-stage bending process, the end portion 11 of the flat wire 10 is bent by the two-stage bending process.

In the present embodiment, the angle at which the end portion 11 of the flat conductive wire 10 is bent to the bent portion is substantially 90 degrees by the first-stage bending process. Accordingly, in the second-stage bending process, the end portion 11 is easily bent by applying laterally symmetrical external forces to the end portion 11 from both ends in the width direction. When the angle of the bent portion in the first stage is larger than 90 degrees (in other words, when the angle of bending is smaller than 90 degrees), it is difficult to apply laterally symmetrical external forces to the end portion 11 from both ends in the width direction in the bending processing in the second stage, and it is difficult to appropriately bend the end portion 11.

The machining rear end portion 110 is inserted into the hollow portion 31 of the sleeve 30. Fig. 1C shows a state in which the processed end portion 110 is inserted into the hollow portion 31. The dimensions in the X-axis direction and the Y-axis direction of the processed rear end portion 110 formed by folding the end portion 11 in two are smaller than the inner diameter of the sleeve 30. Therefore, the machined rear end portion 110 can be easily inserted into the hollow portion 31.

As described above, according to the present embodiment, the end portion 11 of the flat wire 10 is folded in two (more specifically, bent 180 degrees along the center line L (see fig. 1A)), and has a plate shape having a width smaller than the width of the end portion 11 before folding. The dimensions in the X-axis direction and the Y-axis direction of the plate-shaped machined rear end portion 110 are smaller than the inner diameter of the sleeve 30. Therefore, even when the inner diameter of the sleeve 30 is smaller than the width of the flat wire 10, the processed rear end portion 110 can be inserted into the hollow portion 31. Compared to the case where the end portion 11 is not bent and the case where the bending angle of the end portion stays at about 90 degrees as in patent document 1, the wide flat wire 10 can be inserted into the hollow portion 31, and therefore the selection range of the flat wire 10 is increased. From another point of view, the flat wire 10 can be inserted into the sleeve 30 having a smaller inner diameter than in these cases, and therefore the range of selection of the sleeve 30 is increased.

Further, by bending the end portion 11 of the flat wire 10 by 180 degrees along the center line L, the flat wire 10 having the actually increased thickness is inserted into the hollow portion 31, and the ratio of the flat wire 10 in the hollow portion 31 becomes larger than that in the case where the flat wire having the same width as the processed end portion 110 is inserted into the sleeve 30. This reduces the gap in the sleeve 30 after crimping, and therefore, even if there is no additional wire for filling the gap, for example, the bonding strength between the respective members of the flat conductive wire 10, the round wire 21, and the sleeve 30 can be ensured.

The round wire 21 is also inserted into the hollow portion 31 of the sleeve 30. After the flat wire 10 (the processed rear end portion 110) and the round wire 21 are inserted into the sleeve 30, a part of the sleeve 30 is crushed by the crimping tool 200. Thereby, the flat wire 10, the round wire 21, and the sleeve 30 are pressure-bonded to each other in a state where the flat wire 10 and the round wire 21 are housed in the sleeve 30.

Fig. 4 is a diagram illustrating a process of crimping the flat wire 10 and the round wire 21 in the sleeve 30 using the crimping tool 200. Fig. 4A shows a state before crimping. Fig. 4B shows a state during crimping.

The crimping tool 200 has a die 70 and a die 80. The die 70 has a groove 71 extending in the Z-axis direction. The sleeve 30 is disposed in the groove 71.

The up-down direction in fig. 4A is the pressure-bonding direction of the sleeve 30 to the flat wire 10 and the round wire 21. As shown in fig. 4A, a round wire 21 is inserted into the hollow portion of the sleeve 30 in a state of overlapping the processed end portion 110 in the pressure-bonding direction. The sleeve 30 is disposed in the groove 71 in such a direction that the processed rear end portion 110 is located on the die 70 side and the round wire 21 is located on the die 80 side. In the state before the pressure bonding, a gap is formed between the processed rear end portion 110 and the round wire 21, and the processed rear end portion 110 and the round wire 21 are not fixed in the sleeve 30.

The stamper 80 has protrusions 81. When the stamper 80 is lowered from above toward the sleeve 30 to press the sleeve 30, as shown in fig. 4B, the portion (facing portion 32) of the sleeve 30 facing the protrusion 81 is crushed by the protrusion 81. When a part of the sleeve 30 is crushed, the crushed part (the opposite part 32) of the sleeve 30 protrudes toward the inside of the sleeve 30. The flat conductive wire 10 and the round wire 21 are electrically connected by pressing the round wire 21 against the plate-shaped surface 110b of the processed rear end portion 110 by the protruding opposing portion 32.

The processed rear end portion 110 and the round wire 21 are sandwiched and fixed by two portions (the facing portion 32 and the contact portion 33 that contacts the groove 71) of the sleeve 30 that face each other. Thereby, the processed rear end portion 110 and the round wire 21 are pressure-bonded by the sleeve 30.

The round wire 21 is crushed by the facing portion 32 of the sleeve 30 and deformed into a flat shape, and is pressed in a state of being in contact with (for example, in surface contact with) the inner wall surface of the facing portion 32 over a large area and in contact with (for example, in surface contact with) the plate-shaped surface 110b of the processed end portion 110 over a large area. In other words, the round wire 21 is pressed by the sleeve 30, and is held in close contact with the plate-shaped surface 110b and the inner wall surface of the sleeve 30.

The plate-like surface 110a of the processed end portion 110 pressed by the round wire 21 is pressed in a state of being in contact with (for example, in surface contact with) the inner wall surface of the contact portion 33 over a large area. That is, the processed rear end portion 110 is pressed by the sleeve 30, and is held in close contact with the round wire 21 and the inner wall surface of the sleeve 30.

Then, the machined rear end portion 110 is pressed against the sleeve 30 in a state where one of the pair of plate-shaped surfaces 110a, 110b (i.e., the plate-shaped surface 110a) facing in opposite directions by being folded in two is in contact with the inner wall surface of the sleeve 30. From another point of view, the processed end portion 110 is pressed against the sleeve 30 in a state where one (i.e., the plate-shaped surface 110a) of the pair of plate-shaped surfaces 110a and 110b, which are oppositely oriented to each other by being folded in two, is in contact with the inner wall surface of the sleeve 30, and the other (i.e., the plate-shaped surface 110b) is in contact with the inner wall surface of the sleeve 30 via the round line 21.

In this way, in the present embodiment, the facing portion 32 (the sleeve 30) and the round wire 21 are in contact with each other in a large area, and the processed end portion 110 and the contact portion 33 (the sleeve 30) are in contact with each other in a large area. Therefore, when the sleeve 30 is pressure-bonded, a local force is not easily applied to the inner wall of the sleeve 30 from the processed rear end portion 110 or the round wire 21, and the shape variation of the deformed sleeve 30 is reduced as compared with the structure described in patent document 1, for example. Therefore, variations in the contact area and the contact pressure between the machined rear end portion 110 and the sleeve 30 can be suppressed, and variations in the contact resistance between these components can be suppressed. Similarly, variations in contact resistance between the sleeve 30 and the round wire 21 and variations in contact resistance between the round wire 21 and the machined rear end portion 110 are also suppressed.

Further, the machined rear end portion 110 after the folding in two has a shape in which two plate-like portions having a small width are overlapped with a small gap therebetween due to springback of the folded portion (see fig. 5B described later). By flattening the machined rear end portion 110 by pressing the plate-like surface 110a of the machined rear end portion 110 having such a shape into contact with the contact portion 33 of the sleeve 30, the restoring force of the machined rear end portion 110 (i.e., the force to restore the two plate-like portions to a shape in which they are separated by a small interval) and the residual stress caused by the plastic deformation of the sleeve 30 after the pressing are in a state of acting in opposite directions to each other in the sleeve 30. Thus, for example, as compared with a structure in which one end portion of the flat conductive wire that is not folded in two is pressure-bonded in the sleeve 30, a high contact pressure can be obtained over substantially the entire range of the portion where the processed end portion 110 and the sleeve 30 are in contact. In addition, the two plate-like portions forming the machined rear end portion 110 are respectively in a state of being compressed by pressure bonding. The restoring force based on the compressed state also acts in the opposite direction to the residual stress. In addition to the restoring force due to the spring back, the restoring force in the compressed state acts in the opposite direction to the residual stress, and therefore a higher contact pressure is obtained over substantially the entire range of the portion where the machined end portion 110 and the sleeve 30 are in contact. Further, as described above, the flat wire 10 having a substantially increased thickness is inserted into the hollow portion 31 by folding in two, with the result that the gap in the sleeve 30 is suppressed to be small. By suppressing the gap in the sleeve 30 to be small, the force at the time of crimping is reliably applied to the processed rear end portion 110, and the processed rear end portion 110 can be sufficiently deformed. In other words, a sufficient restoring force can be generated at the machined rear end portion 110. This also contributes to obtaining a high contact pressure over substantially the entire range of the portion where the rear end portion 110 and the sleeve 30 are in contact.

In this way, by bringing the machined end portion 110 into contact with the sleeve 30 over a large area and obtaining a high contact pressure over a large area, the contact resistance between the machined end portion 110 and the sleeve 30 is reduced, and the joint strength between the machined end portion 110 and the sleeve 30 is improved. Further, since the clearance in the sleeve 30 is suppressed to be small, the contact resistance between the sleeve 30 and the round wire 21 and between the round wire 21 and the machined end portion 110 is also reduced, and the joint strength between these members is also improved.

In the present embodiment, the two-stage bending process is adopted, so that the end portion 11 of the flat conductive wire 10 can be easily and appropriately bent (in other words, the end portion 11 is along the center line L). In the second-stage bending process, by appropriately bending the end portion 11, as shown in an enlarged view a of fig. 4A, the positions of both end surfaces 110c in the X-axis direction (the positions in the width direction of the end portion 110 after the process) are aligned. By aligning the positions of the two end surfaces 110c, the dimension in the width direction of the machined rear end portion 110 can be suppressed to be smaller than in the case where these positions are not aligned. This enables, for example, the flat wire 10 to be inserted into the sleeve 30 having a smaller inner diameter, and the gap in the sleeve 30 to be kept small. As a result, the contact area and the contact pressure between the respective members are easily ensured in the sleeve 30, the contact resistance between the respective members can be reduced, and the joint strength between the respective members can be improved.

Fig. 1D shows a state in which the processed end portion 110 and the round wire 21 are pressed against the sleeve 30. As shown in fig. 1D, a portion of the sleeve 30 is collapsed. In this way, by using the crimping tool 200 that crushes a part of the sleeve 30, not the entire length of the sleeve 30, the force required for crushing the sleeve 30 becomes small, and the crimping of the sleeve 30 by the processed rear end portion 110 and the round wire 21 is facilitated. Further, the sleeve 30 may be crushed over the entire range in order to press-fit the processed rear end portion 110 and the round wire 21 more firmly.

Fig. 5A is a diagram showing the flat wire 10 before the end portion 11 is folded in two. Fig. 5B is a view showing the flat wire 10 after the end portion 11 is folded in two.

The flat wire 10 is entirely (entirely) covered with an insulating coating film. In order to electrically connect the flat wire 10 and the round wire 21, the insulating coating needs to be removed.

Generally, the flat wire is subjected to removal of insulating coatings on both surfaces (both surfaces of the end portion of the flat wire) of a contact portion with a connecting member (a wire such as a round wire, a sleeve, or the like), specifically, a portion to be pressure-bonded. In view of facilities, when only one surface of the insulating film can be removed in one removing step, it is necessary to perform the removing step twice to remove the insulating films on both surfaces.

In contrast, in the present embodiment, only the hatched area shown in fig. 5A (i.e., only one surface of the end portion 11 of the flat wire 10) may be removed. Specifically, in the present embodiment, only the hatched area is removed, and the end portion 11 is folded in two so that the surface including the hatched area faces outward, whereby both surfaces of the plate-shaped surface 110a that contacts the contact portion 33 of the sleeve 30 and the plate-shaped surface 110B that contacts the round wire 21 are in a state where no insulating coating is present, as shown in fig. 5B. Therefore, in the present embodiment, even when only one surface of the insulating film can be removed in one removing step by the equipment, the removing step may be performed only once.

A method of connecting the flat wire 10 and the sleeve 30 as the connecting member will be described with reference to the drawings.

First, in the removing step, the insulating coating covering one surface of the insulating coating of the end portion 11 of the flat wire 10 is removed (for example, peeled off) (see fig. 5A and 5B). The end portion 11 from which the insulating coating is removed is bent at a first angle (90 degrees) along the center line L in the longitudinal direction of the flat wire 10 in the first bending step (see fig. 2A to 2C and fig. 3A to 3C). The end portion 11 bent to the first angle is bent to a second angle (180 degrees) larger than the first angle along the center line L in the longitudinal direction of the flat conductive wire 10 in the second bending step. Thus, the end portion 11 has a plate shape (i.e., the processed rear end portion 110) having a width smaller than the width before being bent at the first angle (see fig. 1B). In the bending step, the end portion 11 is bent so that the surface from which the insulating coating is removed in the removing step faces outward (see fig. 5B). Next, in the insertion step, the rear end portion 110 is machined and inserted into the hollow portion 31 of the sleeve 30 (see fig. 1C). The machined end portion 110 inserted into the hollow portion 31 is pressed against the sleeve 30 in the pressing step in a state where the plate-shaped surface 110a is in surface-to-surface contact with the inner wall of the sleeve 30 and the plate-shaped surface 110B is in surface-to-surface contact with the round wire 21 (see fig. 1D, 4A, and 4B). Thereby, a connection structure in which the processed end portion 110 housed in the sleeve 30 and the round wire 21 are pressure-connected in the sleeve 30 is obtained.

The above is a description of the embodiments of the present invention, but the present invention is not limited to the configurations of the above embodiments, and various modifications are possible within the scope of the technical idea. For example, the present invention also includes an embodiment in which at least a part of the technical configuration of one or more embodiments described in the specification and a known technical configuration are appropriately combined.

In the present embodiment, the sleeve 30 as the cylindrical portion constitutes the entire connecting member, but the embodiment of the present invention is not limited to this configuration. The connecting member may be a crimp terminal (a metal member in which a connecting tube portion (cylindrical portion) that houses an end portion of the flat wire and is crushed by a crushing device and a terminal portion that connects round wires by a screw or the like are integrally formed) as illustrated in patent document 1. In the case where the connection member is a crimp terminal, it is not necessary to insert the round wire 21 into the hollow portion 31 of the sleeve 30. At this time, both the plate-shaped surface 110a and the plate-shaped surface 110b are pressed against the sleeve 30 in a state of being in contact with the inner wall surface of the sleeve 30.

In the above embodiment, the sleeve 30 has a cylindrical shape, but the embodiment of the present invention is not limited to this configuration. For example, the sleeve 30 may have a ring shape having an elliptical cross-sectional shape in the XY plane.

In the above embodiment, the flat wire 10 and the round wire 21 are connected only by crimping, but the embodiment of the present invention is not limited to this configuration. For example, after the processed rear end portion 110 and the round wire 21 are pressed against the sleeve 30, the connection between the processed rear end portion 110 and the round wire 21 or between the processed rear end portion 110 and the sleeve 30 may be reinforced by brazing or welding. Thereby, the processed rear end portion 110 and the round wire 21 are more firmly fixed, and the contact resistance is suppressed to be smaller.

Description of the reference numerals

10 Flat wire

11 end of the tube

11a, 11b plate-like surfaces

20 coated wire

21 round wire

30 sleeve

The rear end portion is processed 110.