JP2022047318A - Molding method of band-like member - Google Patents

Abstract

To suppress a tilt of a sidewall rubber with respect to a case.SOLUTION: A molding method of a band-like member comprises: molding a case 17 on a first drum D1; removing the case 17 from the first drum D1; bringing a pair of support portions 30 of a second drum D2 close to each other and reducing the diameter; placing the case 17 concentrically on an outer peripheral side of the pair of support portions 30; individually performing a diameter-expanding operation in which the first pressure P1 is supplied to the pair of support portions 30 to bring the pair of support portions 30 to the inner peripheral surface 17a of the case 17 and a separation operation in which the pair of support portions 30 are separated from each other, thereby bridging the case 17 to the pair of supports 30 to hold it; and further, attaching a sidewall rubber 18 to the case 17 while supplying a second pressure P2 higher than the first pressure P1 to the pair of support portions 30 while maintaining the pair of support portions 30 in an expanded state to mold a carcass band 19.SELECTED DRAWING: Figure 6D

Description

The present invention relates to a method for forming a band member.

The inner liner and carcass ply are pasted on the first drum to form a case, the case is transferred to the second drum, and the sidewall rubber is further pasted on the second drum to form a carcass band (band member). ) Is known to be molded (see, for example, Patent Document 1). The second drum has a pair of support portions provided apart from each other in the drum axis direction. The pair of support portions are formed in a cylindrical shape, have an outer diameter that can be expanded or contracted, and are configured to be able to approach and separate from each other in the drum axis direction.

In order to transfer the case from the first drum to the second drum, the pair of support parts of the second drum are brought close to each other in the direction of the drum axis in advance, and the outer diameter of each is smaller than the inner diameter of the case. It is necessary to reduce the diameter so as to. Next, the case is removed from the first drum and placed concentrically on the outer peripheral side of the pair of support portions. After that, the case is supported by the outer peripheral portion of the pair of support portions by expanding the diameter of the pair of support portions and separating them outward in the drum axial direction.

Japanese Unexamined Patent Publication No. 2002-240162

When the case is transferred to the second drum, when the pair of support portions move outward in the drum axial direction while expanding the diameter, the inner peripheral surface of the case is locally strongly pressed outward in the radial direction. May move outward in the drum axis direction. In this case, as shown in FIG. 8A, since the case 91 is locally stretched outward in the drum axial direction, the case 91 is supported in an inclined state with respect to the second drum D20.

As a result, as shown in FIG. 8B, when the sidewall rubber 92 is wound in parallel with the second drum D20 in the circumferential direction to form the carcass band 93, the sidewall rubber 92 is inclined with respect to the case 91. become. As shown in FIG. 8C, when the carcass band 93 is separated from the second drum D20 and the case 91 is supported so as to extend in parallel in the circumferential direction, the sidewall rubber 92 meanders in the axial direction in the circumferential direction. become.

Although not shown, the carcass band 93 is coupled to the inner peripheral surface of the tread band containing the tread rubber to form a green tire, and the side of the pneumatic tire manufactured by vulcanizing the green tire. The imbalance increases due to the meandering of the wall rubber 92.

The present invention provides a method for molding a band member, which can suppress the inclination of the sidewall rubber with respect to the case when the case is transferred from the first drum to the second drum and the sidewall rubber is attached to form the band member. The challenge is to provide.

The present invention
A cylindrical first drum and a second drum are prepared, wherein the second drum is configured to be expandable and contractible in the radial direction of the drum according to the pressure of the supplied working medium, and is configured in the axial direction of the drum. It has a pair of supports that are configured to be close to and separated from each other.
The inner liner and the carcass ply are attached to the first drum in order.
A pair of beads are assembled at positions on the outer peripheral surface of the carcass ply that are separated from each other in the drum axis direction.
The portion of the carcass ply located outside the pair of beads in the drum axial direction is folded back inward in the drum axial direction to form a case.
The case is removed from the first drum,
The pair of support portions of the second drum are positioned at axial inner positions close to each other in the drum axial direction, and their outer diameters are reduced so as to be smaller than the inner diameter of the case.
The case is placed concentrically on the outer peripheral side of the pair of support portions.
A diameter-expanding operation that supplies a first pressure to the pair of support portions to bring the pair of support portions to the inner peripheral surface of the case, and a separation that separates the pair of support portions outward in the drum axial direction. The operation is carried out separately, whereby the case is held by the outer peripheral surface of the pair of support portions.
While supplying a second pressure higher than the first pressure to the pair of support portions to maintain the diameter-expanded state of the pair of support portions, sidewall rubber is further attached to the case to form a band member. Provided is a method for forming a band member to be formed.

According to the present invention, the pair of support portions are individually subjected to the diameter expansion operation and the separation operation, and the first pressure is lower than the second pressure supplied when the sidewall rubber is attached. , The pair of supports are separated without excessively pressing the case outward in the radial direction. Further, it is easy to correct the inclination of the case with respect to the second drum by the diameter-expanding operation and the separating operation of the pair of support portions at the first pressure. Therefore, the sidewall rubber can be attached while suppressing the inclination with respect to the case.

Further, at the time of transferring the case to the second drum,
The pair of support portions may perform the separation operation after performing the diameter expansion operation.

According to this configuration, since the pair of support portions move from the inside to the outside in the drum axial direction in a state of being substantially in contact with the inner peripheral surface of the case, it is easier to further suppress the inclination of the case with respect to the second drum.

Further, the first pressure may be the minimum pressure required for the pair of support portions to expand in diameter to the inner peripheral surface of the case.

According to this configuration, the pair of support portions move outward in the drum axial direction while being displaced in the drum radial direction along the shape of the inner peripheral surface of the case, so that the case is strongly locally pressed in the drum axial direction. It is prevented from being pulled to. Therefore, it is easier to suppress the inclination of the case with respect to the second drum.

Further, each of the pair of support portions has an outer peripheral portion divided in the circumferential direction into a plurality of first segments and a plurality of second segments, and the first segment and the second segment alternate in the circumferential direction. Is located in
At the time of the separation operation
The first segment is in contact with the inner peripheral surface of the case by the first pressure.
The second segment may be located radially inside the inner peripheral surface of the case.

According to this configuration, in the pair of support portions, only the first segment abuts on the inner peripheral surface of the case during the separation operation, so that the pair of support portions also abut on the inner peripheral surface of the case as compared with the case where the second segment also abuts on the inner peripheral surface of the case. It is easy to reduce the sliding resistance of the support part to the inner peripheral surface of the case. As a result, the pair of support portions can be easily separated from each other while suppressing the pulling of the inner peripheral surface of the case in the drum axial direction.

Further, the second segment may be brought into contact with the inner peripheral surface of the case after the separation operation is completed.

According to this configuration, at the end of the separation operation, the inner peripheral surface of the case is supported over the entire circumference by the pair of support portions, so that the sidewall rubber can be stably attached.

Further, it also includes pressing a stitching tool against the outer surface of the band member to stitch.
The second pressure may be set to a pressure required to maintain the diameter-expanded state of the pair of support portions with respect to the pressing force inward in the radial direction by the band member due to the stitching.

According to this configuration, since the band member can be stably stitched, the sidewall rubber can be easily brought into close contact with the case, and the air that may intervene between them can be easily discharged. Therefore, the generation of air pools in the pneumatic tire manufactured by using the band member is suppressed.

According to the present invention, when the case formed by the first drum is transferred to the second drum and the sidewall rubber is attached to form the band member, the inclination of the sidewall rubber with respect to the case can be suppressed.

The figure which conceptually shows the process of molding a case on the 1st drum. The figure which conceptually shows the process of arranging a case on the outer peripheral side of a 2nd drum. The figure which conceptually shows the process of supporting a case by a 2nd drum. The figure which conceptually shows the process of forming a carcass band on the 2nd drum. The perspective view which shows the schematic structure of the 2nd drum. The figure which shows the preparation process of the 2nd drum before the case is transferred. FIG. 6A is a diagram showing a state in which a case is arranged on the outer peripheral side of the second drum with respect to FIG. 6A. FIG. 6B is a diagram showing a state in which the first segment is moved outward in the radial direction with respect to FIG. 6B. FIG. 6 is a diagram showing a state in which a pair of cylindrical portions are separated from each other in the drum axis direction with respect to FIG. 6C. FIG. 6 is a diagram showing a state in which the second segment is moved outward in the radial direction with respect to FIG. 6D. The figure which shows the operation of the 2nd drum which concerns on the modification. The figure which shows the state which the case is inclined and supported by the 2nd drum. The figure which shows the state which the sidewall rubber was attached to FIG. 8A. FIG. 8B is a diagram showing a state in which the carcass band is removed from the second drum with respect to FIG. 8B.

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings. It should be noted that the following description is merely an example and is not intended to limit the present invention, its application, or its use. In addition, the drawings are schematic, and the ratio of each dimension is different from the actual one.

1 to 4 are diagrams conceptually showing a process of forming a carcass band (band member) using the first drum D1 and the second drum D2 in the tire forming direction according to the embodiment of the present invention. be. With reference to FIG. 1, first, the inner liner 11 is attached in a cylindrical shape to the outer peripheral surface of the cylindrical first drum D1. In the following description, with respect to the first drum D1 and the second drum D2, the central axial direction is referred to as a drum axial direction AD, the radial direction is referred to as a drum radial direction RD, and the circumferential direction is referred to as a drum circumferential direction CD. Further, FIGS. 1 to 4 show only one side of the drum radial direction RD.

The carcass ply 12 is attached to the outer peripheral surface of the inner liner 11 in a cylindrical shape. The carcass ply 12 is one in the present embodiment, and is configured by coating a plurality of carcass cords arranged in parallel with a topping rubber.

A pair of annular beads 13 are assembled on the outer peripheral surface of the carcass ply 12. The pair of beads 13 are located on the outer peripheral surfaces of the carcass ply 12 so as to be separated from each other on both sides of the drum axial direction AD. The bead 13 includes a bead core 14 formed by coating a convergent body such as a steel wire with rubber, and a bead filler 15 made of hard rubber having a substantially triangular cross section attached to the outer peripheral surface of the bead core 14.

Both side portions of the carcass ply 12 located outside the drum axial direction AD with respect to the pair of beads 13 are folded inward around the pair of beads 13 to form the folded portion 12a. In the present specification, the cylindrical member formed on the first drum D1 in which the carcass ply 12 is folded inward in the drum axial direction is referred to as a case 17.

Next, as shown in FIG. 2, the case 17 is removed from the first drum D1 while being supported from the outer diameter side by the transfer 3, and is arranged concentrically on the outer peripheral side of the second drum D2. Next, as shown in FIG. 3, the case 17 is supported on the outer peripheral surface of the second drum D2. Finally, as shown in FIG. 4, a pair of sidewall rubbers 18 are attached to the outer peripheral surface of the case 17 on the second drum D2 in the drum axial direction AD, and then the side using the stitching tool 5 is used. The carcass band 19 is formed by pressing (stitching) the outer surface of the wall rubber 18 toward the case 17.

FIG. 5 is a perspective view showing a schematic configuration of the second drum D2. As shown in FIG. 5, the second drum D2 includes a pair of support portions 30 spaced apart from each other in the drum axial direction AD, and a pair of rotary drive portions 41 for rotationally driving the pair of support portions 30 around the central axis O1. It has an axial drive unit 42 that brings the support unit 30 close to and separated from each other in the drum axial direction AD. The rotation drive unit 41 can be realized by, for example, a well-known rotation mechanism using a servomotor. Further, the axial drive unit 42 can be realized by, for example, a well-known moving mechanism using a servomotor and a ball screw.

The support portion 30 has an outer peripheral portion 31 formed in a cylindrical shape. The outer peripheral portion 31 has an outer end surface 32 and an outer peripheral surface 33 located outside the drum axial direction AD, and an annular chamfer 34 for diagonally connecting these is formed between the outer end surface 32 and the outer peripheral surface 33. ing. Further, in the support portion 30, the outer peripheral portion 31 is divided into a plurality of first segments 31A and a plurality of second segments 31B. The first segment 31A and the second segment 31B are arranged alternately in the circumferential direction. In the present embodiment, the first segment 31A and the second segment 31B are provided three by three.

In the drum peripheral direction CD, the peripheral length L1 of the first segment 31A in the drum peripheral direction is longer than the peripheral length L2 of the second segment 31B. The peripheral length L1 is twice or more and four times or less the peripheral length L2, and in the present embodiment, the peripheral length L1 is set to three times the peripheral length L2.

The first segment 31A is configured to be movable in the drum radial direction RD by the first cylinder 37. The second segment 31B is configured to be movable in the drum radial direction by the second cylinder 38. As a result, the support portion 30 is configured to be expandable and contractible in the radial direction.

In the present embodiment, the first cylinder 37 and the second cylinder 38 are air cylinders whose working medium is air, and the rods 37a and 38a are projected and retracted according to the pressure of the air supplied to the cylinders 37b and 38b. Let me. The first segment 31A and the second segment 31B are individually moved radially by the first cylinder 37 and the second cylinder 38.

Specifically, the first cylinder 37 and the second cylinder 38 project the rods 37a and 38a from the cylinders 37b and 38b when the pressure of the supplied air increases, and the rod 37a when the pressure of the supplied air decreases. , 38a is a single-acting cylinder in which the cylinders 37b and 38a are retracted into the cylinders 37b and 38b by a built-in urging means (for example, a coil spring) (not shown). Therefore, the first cylinder 37 and the second cylinder 38 retreat the rods 37a, 38a most from the cylinders 37b, 38b and retract into the cylinders 37b, 38b, depending on the pressure of the supplied air. Move between the edges.

The first cylinder 37 and the second cylinder 38 increase the pressure of the supplied air to the first pressure P1 or higher in order to move the rods 37a, 38a to the protruding end against the urging means. It takes. In other words, the first pressure P1 is the minimum pressure (minimum required pressure) required to move the rods 37a, 38a to the protruding end against the urging means, and the rods 37a, 38a are When the pressure of the supplied air is less than the first pressure P1, the protruding end is not reached.

Further, after the case 17 is supported by the pair of support portions 30, the pressure of the air supplied to the first cylinder 37 and the second cylinder 38 is increased to the second pressure P2, which is higher than the first pressure P1. Let me. The second pressure P2 is, for example, twice or more and four times or less the first pressure P1. In the present embodiment, the second pressure P2 is set to three times the first pressure P1.

By making the second pressure P2 higher than the first pressure P1, it is easy to maintain the rods 37a and 38a at the protruding ends, and it is easy to hold the first segment 31A and the second segment 31B radially outward. As a result, the sidewall rubber 18 can be stably attached to the case 17 while applying tension, and stable stitching can be performed.

Further, when the pressure of the supplied air of the first cylinder 37 and the second cylinder 38 is less than the third pressure P3 (for example, atmospheric pressure) lower than the first pressure P1, the rods 37a and 38a are provided by the above-mentioned urging means. Is located at the receding end.

FIG. 5 shows a state in which air is supplied at the first pressure P1 for both the first cylinder 37 and the second cylinder 38, so that both the first segment 31A and the second segment 31B are radially movable. It is located at the outer diameter side end of the range.

The transfer of the case 17 to the second drum D2 will be described in detail with reference to FIGS. 6A to 6E.

FIG. 6A shows a preparatory step for the second drum D2, which is performed before the case 17 is transferred. As shown in FIG. 6A, in the preparatory step, the pair of support portions 30 are located inside the drum axial direction AD so as to approach each other. At this time, the distance L3 in the drum axial direction AD between the outer end surfaces 32 of the pair of support portions 30 is shorter than the length L4 (see FIG. 6B) in the drum axial direction AD of the case 17.

Further, in the support portion 30, by setting the pressure of the air supplied to the first cylinder 37 and the second cylinder 38 to the third pressure P3, the pair of support portions 30 are provided with the first segment 31A and the second segment 31B. Is located at the inner diameter side end of the movable range in the radial direction, and is in a reduced diameter state. At this time, the first segment 31A is located on the outer diameter side of the second segment 31B, and the positions of the respective circumferential ends in the drum circumferential CD overlap. Therefore, the largest outer diameter of the support portion 30 is the outer diameter A1 on the outer peripheral surface of the first segment 31A. The outer diameter A1 is smaller than the inner diameter A2 of the case 17 (see FIG. 6B).

Next, as shown in FIG. 6B, the case 17 supported by the transfer 3 is concentrically arranged on the outer peripheral side of the pair of support portions 30. At this time, the transfer 3 supports the case 17 so that the center position of the case 17 and the center position between the pair of support portions 30 coincide with each other in the drum axial direction AD.

Next, as shown in FIG. 6C, a diameter-expanding operation for expanding the outer diameter of the pair of support portions 30 is performed. Specifically, by increasing the pressure of the air supplied to the first cylinder 37 to P1 and positioning the rod 37a at the protruding end, the first segment 31A is positioned at the outer diameter side end in the radial direction. The diameter of the support portion 30 is expanded. As a result, the outer peripheral surface of the first segment 31A comes into contact with the inner peripheral surface of the case 17. That is, the largest outer diameter of the support portion 30 is equal to the inner diameter A2 of the case 17 on the outer peripheral surface of the first segment 31A. At this time, the pressure of the air supplied to the second cylinder 38 is maintained at P3.

Next, as shown in FIG. 6D, the axial drive unit 42 performs a separation operation in which the pair of support portions 30 are separated from each other to the outside of the drum axial direction AD so as to be separated from each other. At this time, since only the first segment 31A is located at the outer diameter side end in the radial direction, the second segment 31B also has an inner peripheral surface of the case 17 as compared with the case where it is also located at the outer diameter side end. The increase in sliding resistance between them is suppressed.

Air is supplied to the first cylinder 37 at the first pressure P1, and as described above, the first pressure P1 is the minimum pressure required to reach the protruding end of the rod 37a, so that the first cylinder 37 has a first cylinder 37. The first segment 31A is supported by a force that easily displaces inward in the radial direction when an external force is applied.

As a result, the pair of support portions 30 are displaced in the drum axial direction RD along the inner peripheral surface 17a of the case 17, that is, along the radial unevenness of the inner peripheral surface 17a of the case 17, and the drum axial direction AD. Move to the outside of. Therefore, the pair of support portions 30 do not strongly press the inner peripheral surface 17a of the case 17 to the outside of the drum radial direction RD when moving to the drum axial direction AD.

The axial drive unit 42 sets the amount of movement of the pair of support portions 30 to a length until the chamfer 34 is located at the outer end portion 17b of the drum axial direction AD of the case 17. Since the bead 13 is located at the outer end portion 17b, the outer end portion 17b has an increased thickness as compared with the residual portion and bulges inward in the radial direction. That is, when the pair of support portions 30 reach the outer end in the drum axial direction AD, the outer end portion 17b of the case 17 falls into the chamfer 34, whereby the case 17 is positioned on the pair of support portions 30.

Next, as shown in FIG. 6E, the pressure of the air supplied to the second cylinder 38 is increased to P1 to position the rod 38a at the protruding end, whereby the second segment 31B is placed on the outer diameter side in the radial direction. Position at the edge. As a result, the second segment 31B, together with the first segment 31A, constitutes an outer peripheral portion 31 connected in the circumferential direction, and the case 17 is stably supported on the entire circumference of the outer peripheral portion 31 of the pair of support portions 30. To.

This completes the transfer of the case 17 to the second drum D2. Next, the pressure of the air supplied to the first cylinder 37 and the second cylinder 38 is increased to the second pressure P2. Finally, the rotation drive unit 41 rotates the second drum D2 to attach the sidewall rubber 18, and then stitches the carcass band to form the carcass band.

As described above, the first segment 31A and the second segment 31B are firmly supported by the second pressure P2 at the outer diameter side end, so that the sidewall rubber 18 can be attached and the pressing force by the stitching tool 5 can be applied. It easily resists external force and suppresses inward displacement in the radial direction. Therefore, the carcass band 19 is stably molded.

According to the carcass band molding method according to the embodiment described above, the following effects are obtained.

(1) The pair of support portions 30 are individually subjected to the diameter expansion operation and the separation operation, and the first pressure P1 is lower than the second pressure P2 supplied when the sidewall rubber 18 is attached. .. The pair of support portions 30 are separated from each other without excessively pressing the case 17 outward in the radial direction. Further, it is easy to correct the inclination of the case 17 with respect to the second drum D2 by the diameter-expanding operation and the separating operation of the pair of support portions 30 at the first pressure P1. Therefore, the sidewall rubber 18 can be attached while suppressing the inclination with respect to the case 17.

(2) Since the pair of support portions 30 are separated from each other after the diameter expansion operation of the first segment 31A, the pair of support portions 30 are inside the drum axial direction AD along the inner peripheral surface 17a of the case 17. Since it moves outward from the second drum D2, it is easier to further suppress the inclination of the case 17 with respect to the second drum D2.

(3) Since the pair of support portions 30 move to the outside of the drum axial direction AD while allowing the displacement of the drum radial direction RD along the shape of the inner peripheral surface 17a of the case, the case 17 is locally drum-diametered. It is prevented from being pulled in the drum axial direction AD while strongly pressing in the direction RD. Therefore, it is easier to suppress the inclination of the case 17 with respect to the second drum D2.

(4) In the pair of support portions 30, only the first segment 31A abuts on the inner peripheral surface 17a of the case 17 during the separation operation, so that the second segment 31B also abuts on the inner peripheral surface 17a of the case 17. Therefore, it is easy to reduce the sliding resistance of the pair of support portions 30 with respect to the inner peripheral surface 17a of the case 17. As a result, the pair of support portions 30 can be easily separated from each other while suppressing the pulling of the inner peripheral surface 17a of the case 17 in the drum axial direction AD.

(5) At the end of the separation operation, the second segment 31B is also located at the outer diameter side end, so that the inner peripheral surface 17a of the case 17 is supported over the entire circumference by the pair of support portions 30, so that the sidewall rubber 18 is used. Is stable and easy to paste.

(6) At the time of attaching the sidewall rubber 18 and performing stitching, the pressure of the air supplied to the first cylinder 37 and the second cylinder 38 is twice or more and four times or less the first pressure P1. The pressure is increasing to P2. As a result, the first segment 31A and the second segment 31B are firmly supported by the outer diameter side end, so that they can easily resist external forces such as the attachment of the sidewall rubber 18 and the pressing of the stitching tool 5, and the radial direction. Inward displacement is suppressed.

As a result, the sidewall rubber 18 is easily brought into close contact with the case 17, and air that may intervene between them is easily discharged. Therefore, the generation of air pools in the pneumatic tire manufactured by using the carcass band 19 is suppressed.

If the second pressure P2 is less than twice the first pressure P1, the supporting force to the outer diameter side ends of the first segment 31A and the second segment 31B is insufficient, and the subsequent sidewall rubber 18 is attached or attached. When stitching is performed, the first segment 31A and the second segment 31B may be displaced inward in the radial direction. When the second pressure P2 exceeds four times the first pressure P1, the energy consumption increases so as to unnecessarily increase the pressure of the air.

(7) Of the first segment 31A and the second segment 31B, the pair of support portions 30 are configured to be separated from each other while only the first segment 31A having a long peripheral length L1 is expanded in diameter. As a result, it is easy to stably separate the pair of support portions 30 along the inner peripheral surface 17a while supporting the inner peripheral surface 17a of the case 17 in a wider range.

If the peripheral length L1 is less than twice the peripheral length L2, the support range of the case 17 in the circumferential direction by the first segment 31A is likely to be insufficient, and the case 17 may be deformed into a polygonal shape. When the peripheral length L1 exceeds four times the peripheral length L2, the support range of the case 17 with respect to the inner peripheral surface 17a by the first segment 31A becomes excessive, and the sliding resistance between the case 17 and the inner peripheral surface 17a increases. The case 17 is easily pulled in the AD in the drum axial direction and easily tilted.

In the above embodiment, the pair of support portions 30 are designed to perform the separation operation after performing the diameter expansion operation of the first segment 31A, but if the diameter expansion operation and the separation operation are performed individually. This often prevents the inner peripheral surface 17a of the case 17 from being pulled in the drum axial direction AD while being locally strongly pressed against the drum radial direction RD.

For example, as shown in FIG. 7, the pair of support portions 30 may be separated from each other and then the diameter of the first segment 31A may be expanded. If the diameter expansion operation is performed first, the first segment 31A moves along the inner peripheral surface 17a of the case 17 during the separation operation, so that the misalignment of the case 17 is likely to be corrected. Therefore, it is preferable to perform the separation operation after performing the diameter expansion operation.

The present invention is not limited to the configuration described in the above embodiment, and various modifications can be made.

3 Transfer 5 Stitching tool 13 Bead 17 Case 18 Side wall rubber 19 Carcass band 30 Support part 31A 1st segment 31B 2nd segment 34 Chamfer 37 1st cylinder 38 2nd cylinder 42 Axial drive part D1 1st drum D2 2nd Drum P1 1st pressure P2 2nd pressure

Claims (6)

A cylindrical first drum and a second drum are prepared, wherein the second drum is configured to be expandable and contractible in the radial direction of the drum according to the pressure of the supplied working medium, and is configured in the axial direction of the drum. It has a pair of supports that are configured to be close to and separated from each other.
The inner liner and the carcass ply are attached to the first drum in order.
A pair of beads are assembled at positions on the outer peripheral surface of the carcass ply that are separated from each other in the drum axis direction.
The portion of the carcass ply located outside the pair of beads in the drum axial direction is folded back inward in the drum axial direction to form a case.
The case is removed from the first drum,
The pair of support portions of the second drum are positioned at axial inner positions close to each other in the drum axial direction, and their outer diameters are reduced so as to be smaller than the inner diameter of the case.
The case is placed concentrically on the outer peripheral side of the pair of support portions.
A diameter-expanding operation that supplies a first pressure to the pair of support portions to bring the pair of support portions to the inner peripheral surface of the case, and a separation that separates the pair of support portions outward in the drum axial direction. The operation is carried out separately, whereby the case is held by the outer peripheral surface of the pair of support portions.
While supplying a second pressure higher than the first pressure to the pair of support portions to maintain the diameter-expanded state of the pair of support portions, sidewall rubber is further attached to the case to form a band member. A method of forming a band member to be formed. At the time of transferring the case to the second drum,
The pair of support portions perform the separation operation after performing the diameter expansion operation.
The method for molding a band member according to claim 1. The first pressure is the minimum pressure required for the pair of support portions to expand in diameter to the inner peripheral surface of the case.
The method for molding a band member according to claim 2. The outer peripheral portion of each of the pair of support portions is divided into a plurality of first segments and a plurality of second segments in the circumferential direction, and the first segment and the second segment are alternately arranged in the circumferential direction. Has been
At the time of the separation operation
The first segment is in contact with the inner peripheral surface of the case by the first pressure.
The second segment is located radially inside the inner peripheral surface of the case.
The method for forming a band member according to claim 2 or 3. The second segment is brought into contact with the inner peripheral surface of the case after the separation operation is completed.
The method for molding a band member according to claim 4. Further comprising pressing a stitching tool against the outer surface of the band member to stitch.
The second pressure is set to a pressure required for the pair of support portions to maintain a diameter-expanded state with respect to a pressing force inward in the radial direction by the band member due to the stitching.
The method for molding a band member according to any one of claims 1 to 5.

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