阅读说明：本技术 模具、轮胎的制造方法以及轮胎 (Mold, tire manufacturing method, and tire ) 是由 小森洋辅 早苗隆平 于 2019-07-24 设计创作，主要内容包括：提供模具、轮胎的制造方法以及轮胎,能够抑制制造成本并且提高硫化成型的轮胎的耐偏磨损性能和噪音性能。模具(1)用于使轮胎(11)硫化成型。该模具(1)包含用于使胎面胶(13)成型的沿周向分割而成的多个组合模(2)。组合模(2)通过互相连接而形成了经由组合模(2)之间的接缝(3)实际上沿周向连续的胎面成型面(4)。接缝(3)包含有相对于轴向倾斜的倾斜接缝(5)。倾斜接缝(5)在胎面成型面(4)的轴向的端部(4e)之间呈直线状延伸。(Provided are a mold, a method for manufacturing a tire, and a tire, which can suppress the manufacturing cost and improve the uneven wear resistance and noise performance of a tire molded by vulcanization. The mold (1) is used for vulcanizing and molding a tire (11). The mold (1) comprises a plurality of split molds (2) divided in the circumferential direction for molding the tread rubber (13). The split dies (2) form, by being connected to each other, a tread forming surface (4) that is continuous in the substantially circumferential direction via the joint (3) between the split dies (2). The seam (3) comprises an inclined seam (5) inclined with respect to the axial direction. The inclined joint (5) extends linearly between the axial ends (4e) of the tread molding surface (4).)

1. A mold for vulcanization molding of a tire, wherein,

the mold comprises a plurality of combined molds which are used for molding the tread rubber and are divided along the circumferential direction,

the split dies form a tread forming surface that is substantially continuous in the circumferential direction via a joint between the split dies by being connected to each other,

the seam comprises an inclined seam inclined with respect to the axial direction,

the inclined joint extends linearly between the axial ends of the tread forming surface.

2. The mold of claim 1,

the combined die is provided with a main protrusion part extending along the circumferential direction and an auxiliary protrusion part crossed with the main protrusion part,

the oblique seam extends so as to intersect only the main protrusion.

3. The mold according to claim 1 or 2,

the oblique seam is inclined at an angle of 20 ° or less with respect to the axial direction.

4. The mold according to any one of claims 1 to 3,

the oblique seam includes: a 1 st inclined seam inclined in a 1 st direction with respect to the axial direction; and a 2 nd oblique seam inclined with respect to the axial direction toward a 2 nd direction opposite to the 1 st direction.

5. The mold according to any one of claims 1 to 4,

the seam includes a plurality of the inclined seams having mutually different angles with respect to the axial direction.

6. The mold according to any one of claims 1 to 5,

the seam comprises a non-oblique seam extending linearly in the axial direction.

7. The mold according to any one of claims 1 to 6,

the angles with respect to the axial direction of a pair of the seams adjacent in the circumferential direction are different from each other.

8. The mold of claim 7,

the difference in the angles is 23 ° or less.

9. The mold according to any one of claims 1 to 8,

the number of the combined dies is 8-13.

10. The mold according to any one of claims 1 to 9,

the number of the oblique seams is more than 50% of the number of the combined dies.

11. A method of manufacturing a tire, wherein,

the method for manufacturing a tire is a method for vulcanization molding the tire using the mold according to any one of claims 1 to 10.

12. A tire having a tread portion, wherein,

the tread portion comprises the tread rubber vulcanized and molded by the mold of any one of claims 1 to 10,

a plurality of transverse cuts extending along the joint are formed in the tread rubber,

the transverse tangent includes an inclined transverse tangent extending obliquely with respect to the tire axial direction.

Technical Field

The present invention relates to a mold for vulcanizing and molding a tire, a method for manufacturing a tire using the mold, and a tire vulcanized and molded using the mold.

Background

Conventionally, it is known to form a tire having a tread portion by vulcanization molding. The mold for vulcanizing and molding the tire includes, for example, a plurality of segment molds (segments) divided in the circumferential direction for molding the tread rubber. Such split molds form a tread molding surface that is substantially continuous in the circumferential direction via a joint between the split molds by being connected to each other.

For example, the following patent document 1 proposes a mold: the optimum mold is designed based on the pitch arrangement pattern determined in the layout design, thereby optimizing the dividing position (position of the joint) of the plurality of combination molds.

Patent document 1: japanese patent laid-open publication No. 2005-246931

In the mold of patent document 1, since the seam extends in the axial direction, when the tire molded by vulcanization runs on a road surface, input from the road surface to a transverse tangent line formed at a portion corresponding to the seam is performed simultaneously, which becomes a factor of deteriorating a change in radial force of the tire. A tire having a poor radial force variation has a large vibration and noise, and is likely to cause local wear, so that the uneven wear resistance and the noise performance may be deteriorated.

On the other hand, in the mold of patent document 1, for example, by forming the joint in a curved or bent shape, when the tire molded by vulcanization is run on a road surface, it is possible to disperse input from the road surface to a portion corresponding to the joint. However, it is difficult to accurately process a curved or buckled seam, and there is a problem that the manufacturing cost of the tire increases.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and a main object thereof is to provide a mold capable of improving uneven wear resistance and noise performance of a tire molded by vulcanization while suppressing manufacturing costs.

The present invention is a mold for vulcanization molding a tire, characterized in that the mold includes a plurality of split molds divided in the circumferential direction for molding a tread rubber, the split molds being connected to each other to form a tread molding surface that is substantially continuous in the circumferential direction via a joint between the split molds, the joint including an inclined joint inclined with respect to the axial direction, the inclined joint extending linearly between axial end portions of the tread molding surface.

In the mold of the present invention, it is preferable that the split mold is provided with a main projection extending in a circumferential direction and a sub-projection intersecting the main projection, and the oblique joint extends so as to intersect only the main projection.

In the mold of the present invention, it is preferable that the inclined seam is inclined at an angle of 20 ° or less with respect to the axial direction.

In the mold of the present invention, preferably, the oblique seam comprises: a 1 st inclined seam inclined in a 1 st direction with respect to the axial direction; and a 2 nd oblique seam inclined with respect to the axial direction toward a 2 nd direction opposite to the 1 st direction.

In the mold of the present invention, it is preferable that the seam includes a plurality of the inclined seams having mutually different angles with respect to the axial direction.

In the mold of the present invention, it is preferable that the seam includes a non-inclined seam extending linearly in the axial direction.

In the mold of the present invention, it is preferable that angles with respect to the axial direction of a pair of circumferentially adjacent ones of the seams are different from each other.

In the mold of the present invention, the difference in the angle is preferably 23 ° or less.

In the mold of the present invention, it is preferable that the number of the split molds is 8 to 13.

In the mold of the present invention, it is preferable that the number of the oblique joints is 50% or more of the number of the split molds.

Preferably, the present invention is a method for manufacturing a tire by vulcanization molding using the mold.

The present invention is a tire having a tread portion, preferably, the tread portion includes the tread rubber vulcanized and molded by the mold, and a plurality of transverse tangents extending along the joint are formed on the tread rubber, and the transverse tangents include an inclined transverse tangent extending obliquely with respect to an axial direction of the tire.

In the mold of the present invention, the split molds form, by being connected to each other, a tread molding surface that is practically continuous in the circumferential direction via a joint between the split molds, the joint including an inclined joint that is inclined with respect to the axial direction. When the tire molded by vulcanization is run on a road surface, the inclined joints can contact the portions corresponding to the inclined joints with the road surface in order in the tire axial direction, and therefore, the input from the road surface can be dispersed. Such an inclined seam reduces the radial force variation of the cured tyre. Therefore, the mold of the present invention can improve the uneven wear resistance and the noise performance of the tire vulcanized and molded by using the mold.

In the mold of the present invention, the inclined joint extends linearly between the axial ends of the tread forming surface. Such an oblique joint can be easily processed and maintained, and therefore, the manufacturing cost of the tire can be suppressed. Therefore, the mold of the present invention can suppress the manufacturing cost and improve the uneven wear resistance and noise performance of the tire molded by vulcanization.

Drawings

Fig. 1 is a perspective view of a mold in a clamped state according to an embodiment of the present invention.

Fig. 2 is a perspective view of a mold in an open state and a tire vulcanized and molded by using the mold.

Fig. 3 is a development view of the tread molding surface.

Description of the reference symbols

1: a mold; 2: assembling a die; 3: seaming; 4: a tread forming surface; 4 e: an end portion; 5: a slanted seam; 11: a tire; 13: a tread rubber.

Detailed Description

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a perspective view of a mold 1 in a clamped state according to the present embodiment, and fig. 2 is a perspective view of the mold 1 in an open state and a tire 11 vulcanized and molded by using the mold 1. The mold 1 of fig. 1 and 2 is a partially cut-away perspective view with a part thereof omitted. The tire 11 can be used for various tires such as a pneumatic tire for passenger cars or heavy loads, and a non-pneumatic tire in which pressurized air is not filled in the tire. The tire 11 of the present embodiment is preferably used as a pneumatic tire for a passenger vehicle.

As shown in fig. 1 and 2, the mold 1 is used for vulcanization molding of a tire 11. The mold 1 of the present embodiment includes a plurality of split molds 2 divided in the circumferential direction for molding the tread rubber 13 of the tread portion 12 of the tire 11. The split dies 2 are preferably interconnected to form a tread forming surface 4 that is substantially circumferentially continuous via a joint 3 between the split dies 2. In practice, continuous in the circumferential direction means that a slight discontinuity at the seam 3 is allowed.

The seam 3 of the present embodiment includes an inclined seam 5 inclined with respect to the axial direction. In the oblique joint 5, when the tire 11 molded by vulcanization runs on a road surface, the portions corresponding to the oblique joint 5 sequentially come into contact with the road surface in the tire axial direction, and therefore, the input from the road surface can be dispersed. Such an inclined seam 5 reduces the radial force variation of the vulcanised tyre 11. Therefore, the mold 1 of the present embodiment can suppress vibration, noise, and uneven wear of the tire 11 vulcanized and molded using the mold 1, and can improve the uneven wear resistance and noise performance of the tire 11.

The inclined joint 5 preferably extends linearly between the axial ends 4e of the tread forming surface 4. The inclined joint 5 of the present embodiment extends linearly over the entire region between the axial end portions 4e of the tread molding surface 4. Since such a slant seam 5 is easy to process and easy to maintain, the manufacturing cost of the tire 11 can be suppressed. Therefore, the mold 1 of the present embodiment can suppress the manufacturing cost of the tire 11 and improve the uneven wear resistance and the noise performance of the tire 11.

Here, the axial end 4e of the tread molding surface 4 is a position where a tread end 12e of the tread portion 12 of the tire 11 is formed. In the case of a pneumatic tire, the tread end 12e is a ground contact position located most outward in the tire axial direction when a standard load is applied to the tire 11 in a standard state and the flat ground is in contact with the flat ground at an outer inclination angle of 0 °.

In the case of a pneumatic tire, the "standard state" refers to a no-load state in which the tire 11 is mounted on a standard rim and adjusted to a standard internal pressure.

The "standard Rim" is a Rim determined for each tire from a specification system including the specification under which the tire 11 is based, and is, for example, a "standard Rim (pre-registration リム)" in case of JATMA, a "Design Rim (Design Rim)" in case of TRA, or a "Measuring Rim (Measuring Rim)" in case of ETRTO.

The "standard internal PRESSURE" is an air PRESSURE determined for each TIRE by each specification in a specification system including the specification under which the TIRE 11 is based, and is a maximum value described in "the highest air PRESSURE (highest air permeability)" in case of JATMA, a TIRE LOAD limit AT VARIOUS COLD INFLATION PRESSUREs (TIRE PRESSURE LIMITS) "in case of TRA, and an" INFLATION PRESSURE "in case of ETRTO.

The "standard LOAD" is a LOAD determined for each TIRE by each specification in a specification system including the specification under which the TIRE 11 is based, and is a "maximum LOAD CAPACITY" in case of JATMA, a maximum value described in "TIRE LOAD limit AT COLD INFLATION pressure (TIRE LOAD AT COLD INFLATION pressure) in case of TRA," and a "LOAD CAPACITY (LOAD CAPACITY)" in case of ETRTO.

Next, a more preferable embodiment of the tire 11 vulcanized and molded by using the mold 1 of the present embodiment will be described.

The tire 11 of the present embodiment has a tread portion 12. The tread portion 12 preferably includes a tread rubber 13, and the tread rubber 13 is formed by vulcanization molding using a mold 1 including a plurality of split molds 2. The tread rubber 13 is formed with, for example, a plurality of main grooves 14 extending in the tire circumferential direction and a recessed portion 15 extending in a direction intersecting the main grooves 14. The main groove 14 and the recessed portion 15 are formed by being recessed inward in the tire radial direction from the tread contact surface 12A formed by the tread molding surface 4.

The main groove 14 of the present embodiment extends continuously and linearly in the tire circumferential direction. The main groove 14 may extend in a zigzag shape in the tire circumferential direction, for example. The main groove 14 may extend intermittently in the tire circumferential direction.

The recessed portion 15 includes, for example, a lateral groove 15A and a sipe 15B extending obliquely with respect to the tire axial direction. The main grooves 14 and the recessed portions 15 have shapes designed in advance in order to improve various performances of the tire 11, such as steering stability, wet performance, uneven wear resistance, ride comfort, noise performance, and fuel efficiency, in a balanced manner. In fig. 2, a part of the sipe 15B is omitted.

On the tread rubber 13 of the tire 11, for example, a portion corresponding to the seam 3 between the split molds 2 is formed as a plurality of transverse tangents 16 extending in the tire axial direction along the seam 3. Here, the transverse cut line 16 is a line that is inevitably formed on the tread contact surface 12A during vulcanization molding, and is formed so as to cross the tread contact surface 12A. The transverse tangent line 16 is formed to slightly protrude from the tread surface 12A, for example.

The transverse cut line 16 of the present embodiment includes an inclined transverse cut line 17 extending along the inclined seam 15. Preferably, the oblique transverse tangent 17 extends obliquely to the tire axial direction. In fig. 2, a part of the transverse cut line 16 is illustrated as being visually recognizable. When the vehicle travels on a road surface, the inclined transverse tangent lines 17 sequentially contact the road surface in the tire axial direction, and therefore input from the road surface can be dispersed. Such an inclined transverse line 17 can reduce the radial force variation of the tire 11, suppress vibration, noise, and uneven wear of the tire 11, and improve the uneven wear resistance and noise performance of the tire 11.

The inclined transverse cut line 17 of the present embodiment is formed so as not to intersect the recess 15. Therefore, the recess 15 can be formed in a predetermined overall shape. This prevents the tread portion 12 from being locally excessively rigid due to the formation of the oblique transverse cut line 17 in the recessed portion 15. Therefore, the inclined transverse cut line 17 of the present embodiment can uniformize the rigidity distribution of the tire 11. Such an inclined transverse line 17 can reduce the radial force variation of the tire 11, and can further improve the uneven wear resistance and noise performance of the tire 11. In addition, since such an inclined transverse cut line 17 does not intersect the recessed portion 15, the appearance performance of the tire 11 can be improved.

Next, a more preferred embodiment of the mold 1 of the present embodiment will be described.

Fig. 3 is a development view of the tread molding surface 4 of the mold 1. As shown in fig. 2 and 3, the split mold 2 of the mold 1 of the present embodiment is provided with a main protrusion 6 and a protrusion 7, the main protrusion 6 being used to form a main groove 14 in a tread rubber 13 of a tire 11, and the protrusion 7 being used to form a recess 15 in the tread rubber 13 of the tire 11. The main protrusion 6 extends, for example, along the circumferential direction of the die 1. The protrusion 7 extends, for example, in a direction intersecting the main protrusion 6. The main protrusion 6 and the protrusion 7 preferably protrude radially inward from the tread molding surface 4. In fig. 1 and 2, the main protrusion 6 and the protrusion 7 are not shown.

The main protrusion 6 may have a shape conforming to the shape of the main groove 14 of the tire 11. In addition, it is preferable that the protrusion 7 includes a 1 st protrusion 7A for forming the lateral groove 15A and a 2 nd protrusion 7B for forming the sipe 15B.

The oblique joint 5 of the present embodiment extends so as not to intersect the protrusion 7. Therefore, the protrusion 7 can be formed into the overall shape of the recess 15 designed in advance based on the above-described respective performances. This suppresses excessive rigidity of the portion of the tire 11 that is vulcanized and molded, and makes the rigidity distribution uniform, by the inclined joint 5. Such an inclined joint 5 can reduce the variation in the radial force of the tire 11 formed by vulcanization molding, and can further improve the uneven wear resistance and the noise performance of the tire 11.

The protrusions 7 of the present embodiment are formed to have a plurality of pitches different from each other in the circumferential direction. Preferably, the plurality of pitches are randomly arranged in the circumferential direction. Such a protrusion 7 can reduce pattern noise associated with the tread pattern of the tire 11 molded by vulcanization, and can further improve the noise performance of the tire 11.

Preferably, the seam 3 comprises a plurality of oblique seams 5 having mutually different angles with respect to the axial direction. When the tire 11 molded by vulcanization is run on a road surface, such a joint 3 can effectively disperse the input from the road surface to the oblique transverse line 17 formed along the oblique joint 5, and can further improve the uneven wear resistance and the noise performance of the tire 11. In addition, the oblique joint 5 can suppress the intersection with the projection 7 corresponding to the projections 7 having different pitches.

If the angle of the inclined joint 5 with respect to the axial direction is large, the balance of the mold 1 at the time of mold clamping may be deteriorated, and a large burr along the transverse tangent line 16 may be generated on the tire molded by vulcanization, which may deteriorate the appearance performance of the tire 11. Further, if the angle of the inclined joint 5 with respect to the axial direction is large, the straight running stability of the tire 11 molded by vulcanization may be degraded, and the steering stability performance designed in advance may not be exhibited.

From such a viewpoint, the oblique joint 5 is preferably inclined at angles θ 1 and θ 2 of 20 ° or less, and more preferably at angles θ 1 and θ 2 of 11.5 ° or less, with respect to the axial direction. Therefore, the inclination tangent 17 of the tire 11 molded by vulcanization is inclined at an angle of preferably 20 ° or less, more preferably 11.5 ° or less, with respect to the tire axial direction.

The joint 3 may include a non-inclined joint 8 extending linearly in the axial direction, for example. Since the processing and maintenance of the non-inclined joint 8 are easier, the manufacturing cost of the tire 11 can be further reduced.

It is preferable that the angles with respect to the axial direction of a pair of circumferentially adjacent seams 3 among the seams 3 are different from each other. The pair of seams 3 may be a pair of seams composed of an oblique seam 5 and a non-oblique seam 8, or may be a pair of seams composed of oblique seams 5 having different angles. When the tire 11 molded by vulcanization is run on a road surface, such a joint 3 can more effectively disperse input from the road surface to the transverse line 16 formed along the joint 3, and can further improve uneven wear resistance and noise performance of the tire 11.

The oblique joint 5 may also comprise, for example: a 1 st inclined seam 5A inclined in the 1 st direction with respect to the axial direction; and a 2 nd oblique joint 5B which is oblique to a 2 nd direction opposite to the 1 st direction with respect to the axial direction. When the tire 11 molded by vulcanization is run on a road surface, such an oblique joint 5 can disperse the input from the road surface in different directions by the portion corresponding to the 1 st oblique joint 5A and the portion corresponding to the 2 nd oblique joint 5B.

The 1 st oblique joint 5A is preferably inclined in the 1 st direction at an angle θ 1 of 20 ° or less with respect to the axial direction. The 2 nd oblique joint 5B is preferably inclined in the 2 nd direction at an angle θ 2 of 20 ° or less with respect to the axial direction. That is, the 2 nd oblique joint 5B is inclined in the 1 st direction at an angle- θ 2 with respect to the axial direction.

In the case where the 1 st oblique joint 5A and the 2 nd oblique joint 5B are adjacent in the circumferential direction, the difference (θ 1+ θ 2) between the angles of the 1 st oblique joint 5A and the 2 nd oblique joint 5B is preferably 23 ° or less. If the difference (θ 1+ θ 2) between the angles is larger than 23 °, the input from the road surface fluctuates greatly when the tire 11 molded by vulcanization is run on the road surface, and there is a possibility that the tire 11 cannot exhibit the steering stability performance designed in advance.

The number of types of the joint 3 is preferably 30% or more of the number of the split molds 2. Here, the types of the joints 3 include at least 1 of the 1 st oblique joint 5A, the 2 nd oblique joint 5B, and the non-oblique joint 8, and the joints having different angles with respect to the axial direction are classified into one type. When the number of types of the joint 3 is less than 30% of the number of the split mold 2, the effect of scattering input from the road surface when the tire 11 molded by vulcanization travels on the road surface is reduced, and there is a possibility that the uneven wear resistance and the noise performance of the tire 11 are not improved.

When the number of split molds 2 is small, the contact area between each split mold 2 and the tire 11 becomes large, and when the split molds 2 are opened after vulcanization molding, there is a possibility that the tire 11 is deformed. When the number of split molds 2 is large, the configuration of the mold 1 becomes complicated, and the manufacturing cost of the tire 11 may increase. From such a viewpoint, the number of the segment molds 2 is preferably 8 to 13.

The number of split molds 2 is equal to the total number of seams 3, and more specifically to the total number of transverse cuts 16 of the vulcanized tire 11. Therefore, the total number of the seams 3 is preferably 8 to 13 as many as the number of the split dies 2. The total number of the transverse cuts 16 is preferably 8 to 13, as is the total number of the seams 3.

The number of oblique joints 5 is preferably more than 50% of the number of split dies 2. That is, the number of oblique seams 5 is preferably 50% or more of the total number of seams 3. When the number of the inclined joints 5 is less than 50% of the total number of the joints 3 which is the number of the split molds 2, the effect of dispersing the input from the road surface when the tire 11 molded by vulcanization is run on the road surface is reduced, and there is a possibility that the uneven wear resistance and the noise performance of the tire 11 are not improved.

While the above description has been made in detail with respect to the particularly preferred embodiments of the present invention, the present invention is not limited to the above embodiments, and may be modified into various embodiments.