JP2020069775A - Multi-layer rubber member manufacturing apparatus and multi-layer rubber member manufacturing method - Google Patents

Abstract

To provide a multi-layer rubber member manufacturing apparatus and a multi-layer rubber member manufacturing method whereby, change of a cross-sectional shape, size, ratio of rubber regions or the like of the multi-layer rubber member is easily performed only by change of a die plate of each rubber extruder, thereby achieving reduction of equipment cost and improvement of productivity.SOLUTION: There is provided a multi-layer rubber member manufacturing apparatus that forms a multi-layer rubber member G0 in which a cross section thereof is divided into a first rubber region Y1, a second rubber region Y2, and a third rubber region Y3. The manufacturing apparatus comprises first to third conveyors 5 to 7 for respectively conveying first to third rubber bodies G1 to G3 from the first to third rubber extruders 2 to 4. The second conveyor 6 has a downstream end E2L that is interrupted above the first conveyor 5, and a two-layered rubber QA is formed by stacking the second rubber body G2 to be sent from the downstream end E2L on the first rubber body G1 of the first conveyor 5. The third conveyor 7 stacks the third rubber body G3 on the two-layered rubber QA to form the multi-layer rubber member Q0.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a manufacturing apparatus and a manufacturing method of a multilayer rubber member, which is suitable for manufacturing a bead apex rubber of a tire and can easily manufacture a multilayer rubber member having a cross section divided into three rubber regions.

  As shown in FIG. 10, as a bead apex rubber a of a heavy-duty tire, a radially inner rubber region a1 made of hard rubber, a radially outer rubber region a2 made of soft rubber, and a rubber region a2 A rubber having a multilayer structure divided into a sheet-shaped rubber region a3 adjacent to the outer surface in the tire axial direction is used (for example, refer to Patent Document 1).

  This bead apex rubber a having a multilayer structure is conventionally extruded by a three-layer rubber extruding device. The three-layer rubber extruder comprises an extrusion head to which the front ends of the three rubber extruders are attached, to which preformer and die plate are attached. The preformer has a preforming channel, and preforms the rubber extruded separately from each rubber extruder and joins them in a predetermined distribution (distribution according to the area ratio of the rubber regions a1 to a3). Further, the die plate has a molding port, and the preformed combined rubber is extruded into a final sectional shape.

  On the other hand, in the bead apex rubber a, the cross-sectional shape, the size, the ratio of the rubber regions a1 to a3, and the like differ depending on the size and type of the tire. However, in the three-layer rubber extrusion device, when the cross-sectional shape, size, ratio of the rubber regions a1 to a3, etc. are changed, it is necessary to change and replace the preformer and die plate accordingly, which increases equipment cost and Productivity is reduced due to replacement work. In particular, the preformer has a complicated structure and requires a long time for replacement work, and thus is a main cause of the above problems.

JP, 2008-37367, A

  INDUSTRIAL APPLICABILITY The present invention can be particularly suitably applied to the production of bead apex rubber for tires, and easily changes the cross-sectional shape, size, ratio of rubber regions, etc. of a multilayer rubber member only by changing the die plate of each rubber extruder. It is an object of the present invention to provide a manufacturing apparatus and a manufacturing method of a multi-layer rubber member that can contribute to reduction of equipment cost and improvement of productivity.

A first invention of the present application is such that a cross section perpendicular to a length direction has a first rubber region made of a first rubber, a second rubber region made of a second rubber, and a third rubber region made of a third rubber. A manufacturing apparatus for a long-divided multi-layered rubber member,
A first rubber extruder,
A second rubber extruder,
A third rubber extruder,
A first conveyor that conveys a first rubber body extruded from the first rubber extruder,
A second conveyor that conveys a second rubber body that passes above the first conveyor and is extruded from the second rubber extruder in the same direction as the first rubber body;
A third conveyor that conveys a third rubber body extruded from the third rubber extruder,
The second transport conveyor has a downstream end in the transport direction that is interrupted above the transport surface of the first transport conveyor, and a second rubber body fed from the downstream end is transferred to the first transport conveyor. One rubber body is superposed at the first joining position to form a two-layer rubber,
The third conveyor conveys the third rubber body on the second-layer rubber at a second joining position to form a multi-layer rubber member.

  The apparatus for manufacturing a multilayer rubber member according to the present invention comprises a first press-contact means for press-contacting the first rubber body and the second rubber body of the two-layer rubber on the downstream side of the first joining position. Is preferred.

  In the manufacturing apparatus for a multilayer rubber member according to the present invention, a second press-contact means for press-contacting the third rubber body of the multilayer rubber member and the two-layer rubber is provided downstream of the second joining position. preferable.

  In the multilayer rubber member manufacturing apparatus according to the present invention, it is preferable that the first, second and third rubber extruders each include a gear pump at a front end portion thereof.

  In the manufacturing apparatus for a multilayer rubber member according to the present invention, the rubber extrusion speed of the first rubber extruder is changed according to the transfer speed of the first transfer conveyor, and the transfer speed of the second transfer conveyor is changed. Therefore, it is preferable to provide a speed control means for changing the rubber extrusion speed of the second rubber extruder.

  In the manufacturing apparatus for a multilayer rubber member according to the present invention, it is preferable that the multilayer rubber member is for bead apex rubber adhered to the outer peripheral surface of the annular bead core of the tire.

  In the apparatus for manufacturing a multilayer rubber member according to the present invention, it is preferable that the multilayer rubber member includes cutting means for cutting the multilayer rubber member in a predetermined length to sequentially obtain a bead apex rubber.

  In the apparatus for manufacturing a multilayer rubber member according to the present invention, it is preferable that a festoon portion for temporarily storing the multilayer rubber member is arranged between the cutting means and the first conveyor.

In the manufacturing apparatus for a multilayer rubber member according to the present invention, the cutting means is configured to cut the multilayer rubber member such that a first side portion of the bead apex rubber extending in the circumferential direction is longer than a second side portion extending in the circumferential direction. Disconnect,
The second side of each of the bead apex rubbers is preferably located on the radially outer surface of the bead core.

  In the multi-layer rubber member manufacturing apparatus according to the present invention, it is preferable that the cutting means cut the multi-layer rubber member so as to cut an independent triangular or trapezoidal portion from between adjacent bead apex rubbers.

  A second invention of the present application is a method for manufacturing a multi-layer rubber member, wherein the cross-section perpendicular to the longitudinal direction is a first rubber region made of the first rubber, using the multi-layer rubber member manufacturing apparatus of the first invention. A long multi-layered rubber member divided into a second rubber region made of the second rubber and a third rubber region made of the third rubber is manufactured.

  In the manufacturing apparatus for a multilayer rubber member of the present invention, the role of the preformer in the conventional three-layer rubber extrusion apparatus is shared by the first conveyor, the second conveyor, and the third conveyor. Then, the second rubber body sent out from the second conveyor is superposed on and merged with the first rubber body conveyed by the first conveyor to form a two-layer rubber. Further, the third rubber body sent out from the third conveyor is superposed on the two-layer rubber and merged to form a multi-layer rubber member.

  Therefore, when changing the cross-sectional shape, size, ratio of rubber regions, etc. of the multilayer rubber member, only the die plates of the first to third rubber extruders are changed to change the cross-sectional shapes of the first rubber body to the third rubber body, This can be handled by changing the size, etc. That is, the conventional preformer becomes unnecessary, and it is possible to suppress an increase in equipment cost and a decrease in productivity accompanying it. Although the number of types of die plates increases, the die plates have a simple structure and are small in size, so that the influence on the equipment cost and the productivity is smaller than that of the preformer.

It is a side view which shows notionally one Example of the manufacturing apparatus of the multilayer rubber member of this invention. It is a side view which expands and shows the main part. It is a perspective view showing before and after a 1st rubber body and a 2nd rubber body merge. It is sectional drawing explaining the merging of a 1st rubber body and a 2nd rubber body. It is a perspective view which shows the 3rd rubber body and two-layer rubber before and after joining. (A), (b) is sectional drawing which shows the 1st and 2nd press contact means notionally. It is a top view showing pasting to a bead core of a multilayer rubber member. (A), (b) is sectional drawing which shows a cutting means notionally. It is sectional drawing which shows notionally one Example of a multilayer rubber member. It is sectional drawing which shows the bead apex rubber of a tire.

Hereinafter, embodiments of the present invention will be described in detail.
As shown in FIG. 1, a manufacturing apparatus 1 for a multilayer rubber member of the present embodiment (which may be simply referred to as “manufacturing apparatus 1”) includes a first rubber extruder 2 and a second rubber extruder 3. , A third rubber extruder 4 (shown in FIG. 5), a first conveyor 5, a second conveyor 6, and a third conveyor 7. The manufacturing apparatus 1 of this example further includes a first press contacting means 9, a second press contacting means 10, and a cutting means 8.

  The manufacturing apparatus 1 is used to form a long multi-layer rubber member G0.

  As shown in FIG. 9, the multilayer rubber member G0 has a first rubber region Y1 made of the first rubber g1, a second rubber region Y2 made of the second rubber g2, and a third rubber region Y3 in a cross section perpendicular to the length direction. It is divided into a third rubber region Y3 made of rubber g3. In this example, a case where the multilayer rubber member G0 is formed for forming a bead apex rubber is shown.

  Specifically, the multilayer rubber member G0 is cut into a predetermined length, and the cut pieces are attached to the outer peripheral surface of the annular bead core 30 of the tire to form the bead apex rubber 31.

  The bead apex rubber 31 has a main body 31A having a first rubber region Y1 and a second rubber region Y2 and having a substantially triangular cross section. The body portion 31A includes a bottom surface S1 attached to the outer peripheral surface of the annular bead core 30, an inner side surface S2 extending from a tire axial inner end Pi of the bottom surface S1 to a radial outer end Pt, and a tire axial outer end of the bottom surface S1. It is surrounded by the outer surface S3 extending from Po to the radially outer end Pt. Further, the body portion 31A has a first rubber region Y1 on the radially inner side and a second rubber region Y2 on the radially outer side due to the slope S4 connecting the point P1 on the bottom surface S1 and the point P2 on the inner side surface S2. Be divided. The first rubber g1 is formed of a hard rubber having a larger rubber hardness than the second rubber g2, and enhances the bead rigidity of the tire. The bead apex rubber 31 also includes a thin sheet-shaped third rubber region Y3 adjacent to the outer surface S3 of the main body 31A. The third rubber g3 forming the third rubber region Y3 is made of a softer rubber than the second rubber g2, and prevents peeling damage starting from the folded end of the carcass ply.

  As shown in FIG. 1, the first rubber extruder 2, the second rubber extruder 3, and the third rubber extruder 4 (shown in FIG. 5) are each a single-layer rubber extruder, In this example, a screw type extruder main body 12A having a gear pump 12B at the front end is illustrated. The first rubber extruder 2 pushes out the first rubber body G1 having a cross-sectional shape similar to the first rubber region Y1. The second rubber extruder 3 pushes out the second rubber body G2 having a cross-sectional shape similar to the second rubber region Y2. The third rubber extruder 4 pushes out the third rubber body G3 having a cross-sectional shape similar to the third rubber region Y3.

  As the extruder main body 12A and the gear pump 12B, various conventional devices having a well-known structure can be appropriately adopted.

  The first transfer conveyor 5, the second transfer conveyor 6, and the third transfer conveyor 7 each include a belt conveyor unit 11 in this example. The belt conveyor unit 11 has a well-known structure in which a conveyor belt is wound by a plurality of guide rollers so as to be wound around. A roller conveyor may be used instead of the belt conveyor unit 11.

  Then, the first transport conveyor 5 transports the first rubber body G1 received from the first rubber extruder 2 in the length direction to the downstream end E1L in the transport direction. The second transfer conveyor 6 passes above the first transfer conveyor 5. Moreover, the 2nd conveyance conveyor 6 conveys the 2nd rubber body G2 received from the 2nd rubber extrusion machine 3 to the downstream side end part E2L of a conveyance direction in the same direction as the 1st rubber body G1.

  As shown in FIGS. 2 and 3, in this example, the first transport conveyor 5 receives the surface S2a of the first rubber body G1 forming the inner side surface S2 on the transport surface 5s. The second conveyor 6 also receives the surface S2b of the second rubber body G2 forming the inner side surface S2 on the conveyor surface 6s.

  Since the downstream end E2L of the second transfer conveyor 6 is interrupted above the transfer surface 5s of the first transfer conveyor 5, the second rubber body G2 sent out from the downstream end E2L is the first transfer conveyor 5 Are superposed on the first rubber body G1 at the first joining position Q1. Then, on the downstream side of the first joining position Q1, the surface S4a of the first rubber body G1 forming the slope S4 and the surface S4b of the second rubber body G2 are vertically overlapped to form a two-layer rubber GA.

  In the present example, the first conveyor 5 includes an inclined conveyor 5A having a conveyor surface 5s extending upward toward the downstream side in the conveyor direction, and a conveyor surface connected to the inclined conveyor 5A at a bent portion J and extending downstream in the conveyor direction. 5s includes a horizontal transport unit 5B that is substantially horizontal. The downstream end E2L of the second transfer conveyor 6 is interrupted above the inclined transfer unit 5A, and the extension surface of the transfer surface 6s of the second transfer conveyor 6 is flush with the transfer surface 5s of the horizontal transfer unit 5B. It is preferable to make uniform.

  As shown in FIG. 4, the first rubber body G1 on the inclined conveyance unit 5A rises as the conveyance progresses, and the surfaces S4a and S4b overlap with the second rubber body G2 delivered from the downstream end E2L. To be joined. At this time, the extension surface of the transport surface 6s is flush with the transport surface 5s of the horizontal transport portion 5B, so that smooth and accurate joining can be performed. Note that in FIG. 2, for convenience, the transport surface 6s is drawn above the transport surface 5s of the horizontal transport unit 5B by the thickness of the first rubber body G1.

  In order to improve the joining accuracy, the first rubber body is arranged such that the point P2b of the second rubber body G2 forming the point P2 is located on the perpendicular line Z passing through the point P2a of the first rubber body G1 forming the point P2. It is preferable to convey G1 and the second rubber body G2.

  As shown in FIG. 5, the third transfer conveyor 7 transfers the third rubber body G3 extruded from the third rubber extruder 4 onto the two-layer rubber GA, and the two-layer rubber GA and the second rubber GA. The multi-layered rubber member G0 is formed by superposing at the merging position Q2.

  In this example, the third conveyor 7 includes a belt conveyor section 11 and a direction changing section 13. The belt conveyor unit 11 passes above the first transfer conveyor 5 and transfers the third rubber body G3 in a direction intersecting the transfer direction of the first transfer conveyor 5, that is, a direction orthogonal to the transfer direction in this example.

  The direction changing unit 13 changes the direction of the third rubber body G3 received from the belt conveyor unit 11 in the same direction as the two-layer rubber GA on the first transport conveyor 5. In this example, the direction changing portion 13 has an upper guide roller 13a whose axis is oriented in the same direction as the transport direction of the first transport conveyor 5 and a direction whose axis is orthogonal to the transport direction of the first transport conveyor 5. By including a lower guide roller 13b and twisting the third rubber body G3 between them, the orientation of the third rubber body G3 is changed.

  As shown in FIG. 2, the first pressure contact means 9 is arranged downstream of the first merge position Q1, and the second pressure contact means 10 is arranged downstream of the second merge position Q2. It

  The first press-contact means 9 presses the second rubber body G2 of the two-layer rubber GA against the first rubber body G1 to press them together. The second pressing means 10 presses the third rubber body G3 of the multilayer rubber member G0 against the two-layer rubber GA to bring them into pressure contact.

  The first and second press-contact means 9 and 10 have the same structure, and are supported so as to be movable up and down and move downward to press the second rubber body G2 against the first rubber body G1 or the third rubber body G3 into a two-layer rubber. A pressing body 16 for pressing the GA is provided.

  The pressing body 16 includes an elevating tool 17 such as a cylinder, and a pressing roller 19 rotatably supported on a rod end of the lifting tool 17 via a holder 18. As shown in FIGS. 6 (a) and 6 (b), the pressing roller 19 includes a cored bar 19A pivotally supported by the holder 18 and a deformable soft part 19B made of a sponge material or the like arranged around the cored bar 19A. Equipped. Then, due to the compressive deformation of the soft part 19B, for example, in the two-layer rubber GA having a substantially triangular cross section and the multilayer rubber member G0, the second rubber body G2 and the first rubber body G1, and the third rubber body G3 and the two-layer rubber The GA and the GA can be evenly pressed and joined together. As the pressing roller 19, various types can be adopted.

  As shown in FIG. 1, the cutting means 8 receives a multi-layered rubber member G0 continuously fed from the first transfer conveyor 5, and a receiving conveyor unit 14 and a predetermined length of the multi-layered rubber member G0 on the receiving conveyor unit 14. And a cutting portion 15 for sequentially obtaining the bead apex rubber 31 by cutting.

  The receiving conveyor section 14 intermittently feeds the multi-layered rubber member G0, and cuts the multi-layered rubber member G0 with a predetermined length by the cutting section 15 during the stop. A festoon for temporarily storing the multi-layer rubber member G0 between the first transfer conveyor 5 and the receiving conveyor unit 14 in order to synchronize the continuous transfer by the first transfer conveyor 5 and the intermittent feeding by the receiving conveyor unit 14. The part 28 is arranged.

  The “predetermined length” means a length by which the bead apex rubber 31 can be wound around the outer peripheral surface of the annular bead core 30 once.

  As shown in FIG. 7, in order to butt and join the end faces e1 and e2 in the circumferential direction after one turn, the first side portion K1 of the bead apex rubber 31 extending in the circumferential direction is a first side portion extending in the circumferential direction. It is necessary to cut the multilayer rubber member G0 so that it is longer than the two side portions K2. The second side portion K2 corresponds to the bottom surface S1 and is arranged on the radially outer surface of the annular bead core 30. The first side portion K1 corresponds to the outer end Pt.

  For that purpose, the cutting means 8 cuts the multilayer rubber member A0 so as to cut the independent triangular or trapezoidal portion 20 from between the adjacent bead apex rubbers 31, 31. The length Li of the portion 20 to be cut on the first side K1 side is larger than the length Lo on the second side K2 side.

  As shown in an exaggerated manner in FIG. 8A, the cutting portion 15 of this example includes a first cutter 21 whose tooth portion 21a is perpendicular to the length direction of the multilayer rubber member G0, and a cutting portion 15 with respect to the length direction. And a second cutter 22 in which the tooth portion 22a is inclined at an acute angle α. The second cutter 22 cuts the multilayer rubber member G0 on the downstream side of the first cutter 21. In this example, the first cutter 21 and the second cutter 22 are supported by an advancing / retreating tool (not shown) such as a cylinder so as to be capable of advancing / retreating in a direction perpendicular to the tooth portions 21a and 22a, respectively. Further, as shown in FIG. 8B, it is also preferable that the first cutter 21 and the second cutter 22 are inclined at an acute angle β with respect to the thickness direction of the multilayer rubber member G0. By inclining at the angle β in this way, the joining area between the end faces e1 and e2 in the circumferential direction can be increased, and the joining strength can be enhanced. As the cutting part 15, various types can be adopted as long as it has the part 20 and can be cut.

  The manufacturing apparatus 1 of this example further includes speed control means 27 (not shown). The speed control means 27 changes the rubber extrusion speed V1g of the first rubber extruder 2 according to the transfer speed V1c of the first transfer conveyor 5. Further, the speed control means 27 changes the rubber extrusion speed V2g of the second rubber extruder 3 according to the transfer speed V2c of the second transfer conveyor 6.

  Specifically, when forming the multi-layered rubber member G0, usually, the transfer speed V1c of the first transfer conveyor 5, the transfer speed V2c of the second transfer conveyor 6, the transfer speed V3c of the third transfer conveyor 7, and the multi-layered rubber member. The speed at which G0 is attached to the annular bead core 30 is preferably operated at a steady speed equal to each other.

  When cutting the multi-layered rubber member G0, the receiving conveyor unit 14 is stopped. At this time, the transfer speeds V1c to V3c of the first transfer conveyor 5, the second transfer conveyor 6, and the third transfer conveyor 7 are operated at a lower speed than the steady speed, preferably at a low speed close to a stop. Is desirable.

  Therefore, the transfer speeds V1c to V3c are switched to low speeds close to the stop in synchronization with turning on / off of the receiving conveyor unit 14, and the speed control means 27 determines the first to third speeds according to the transfer speeds V1c to V3c. The rubber extrusion speeds V1g to V3g of the rubber extruders 2 to 4 are changed.

  Further, in the method for manufacturing a multilayer rubber member, by using the manufacturing apparatus 1, a cross section perpendicular to the length direction has a first rubber region Y1 made of the first rubber g1 and a second rubber region made of the second rubber g2. The long multi-layered rubber member G0 divided into Y2 and the third rubber region Y3 including the third rubber g3 can be manufactured with a simple structure.

  Although the particularly preferred embodiments of the present invention have been described above in detail, the present invention is not limited to the illustrated embodiments and can be modified into various modes.

1 Manufacturing Apparatus 2 First Rubber Extruder 3 Second Rubber Extruder 4 Third Rubber Extruder 5 First Conveyor 5s Conveying Surface 6 Second Conveying Conveyor 6s Conveying Surface 7 Third Conveying Conveyor 8 Cutting Means 9th 1 pressure contact means 10 2nd pressure contact means 12B gear pump 20 part 27 speed control means 28 festoon part 30 annular bead core 31 bead apex rubber E2L flow side end G0 multi-layer rubber member G1 first rubber body G2 second rubber body G3 third Rubber body GA Two-layer rubber g1 First rubber g2 Second rubber g3 Third rubber K1 First side part K2 Second side part Q1 First merging position Q2 Second merging position Y1 First rubber region Y2 Second rubber region Y3 Third rubber area

Claims (11)

A long multi-layered rubber whose cross section perpendicular to the length direction is divided into a first rubber region made of a first rubber, a second rubber region made of a second rubber, and a third rubber region made of a third rubber. A device for manufacturing a member,
A first rubber extruder,
A second rubber extruder,
A third rubber extruder,
A first conveyor that conveys a first rubber body extruded from the first rubber extruder,
A second conveyor that conveys a second rubber body that passes above the first conveyor and is extruded from the second rubber extruder in the same direction as the first rubber body;
A third conveyor that conveys a third rubber body extruded from the third rubber extruder,
The second transport conveyor has a downstream end in the transport direction that is interrupted above the transport surface of the first transport conveyor, and a second rubber body fed from the downstream end is transferred to the first transport conveyor. One rubber body is superposed at the first merging position to form a two-layer rubber,
The third conveyor conveys the third rubber body on the second-layer rubber at a second merging position to form a multi-layer rubber member.
Multi-layer rubber member manufacturing equipment. Downstream of the first merging position, there is provided a first press-contact means for press-contacting the first rubber body and the second rubber body of the two-layer rubber.
The apparatus for manufacturing a multilayer rubber member according to claim 1. Downstream of the second merging position, a second press-contact means for press-contacting the third rubber body of the multilayer rubber member and the two-layer rubber is provided.
The apparatus for manufacturing a multilayer rubber member according to claim 1.   The said 1st, 2nd, 3rd rubber extruder is equipped with the gear pump in the front-end part, respectively, The manufacturing apparatus of the multilayer rubber member in any one of Claims 1-3. The rubber extrusion speed of the first rubber extruder is changed according to the transfer speed of the first transfer conveyor, and the rubber extrusion of the second rubber extruder is changed according to the transfer speed of the second transfer conveyor. With speed control means to change speed,
The manufacturing apparatus of the multilayer rubber member according to claim 1. The multi-layer rubber member is for bead apex rubber to be attached to the outer peripheral surface of the annular bead core of the tire,
The apparatus for manufacturing a multilayer rubber member according to claim 1. The multilayer rubber member, including a cutting means for cutting the predetermined length to obtain a bead apex rubber sequentially,
The apparatus for manufacturing a multilayer rubber member according to claim 6. A festoon portion for temporarily storing the multilayer rubber member is arranged between the cutting means and the first conveyor.
The apparatus for manufacturing a multilayer rubber member according to claim 7. The cutting means cuts the multilayer rubber member such that a first side portion of the bead apex rubber extending in the circumferential direction is longer than a second side portion extending in the circumferential direction,
A second side of each of the bead apex rubbers is disposed on a radially outer surface of the bead core,
The apparatus for manufacturing a multilayer rubber member according to claim 7. The cutting means cuts the multilayer rubber member so as to cut an independent triangular or trapezoidal portion from between adjacent bead apex rubbers,
The apparatus for manufacturing a multilayer rubber member according to claim 9. The apparatus for manufacturing a multilayer rubber member according to any one of claims 1 to 10, wherein a cross section perpendicular to a length direction includes a first rubber region made of a first rubber and a second rubber region made of a second rubber. Manufacturing a long multi-layered rubber member divided into a third rubber region made of a third rubber,
Method for manufacturing multi-layer rubber member.

Images