Stitcher, stitching method, and tire manufacturing method

Abstract

To provide a stitcher in which a stitch roller hardly turns over a second preliminary molding when rotating a stitch cylinder during stitching in a manufacturing process of a tire.SOLUTION: A stitcher 100 comprises: a stitch cylinder 20 having a piston rod 22; a stich roller 30 attached to the piston rod 22 to press a second preliminary molding 102 to a first preliminary molding 101; a cylinder base 40 for holding the stitch cylinder 20; and a rotating device 50 for rotating the stitch cylinder 20 with respect to the cylinder base 40. The cylinder base 40 has guides 41 for guiding the stitch cylinder 20 so that the stitch cylinder 20 rotates around a reference point 24 at a position of a tip end of the stitch roller 30 when the piston rod 22 is at a reference position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a stitcher used in stitching performed in the tire manufacturing process, a stitching method, and a tire manufacturing method. [Background technology]

[0002] In the tire manufacturing process, a stitching (pressure bonding) is performed in which a cylindrical second preform is pressed against the outer peripheral surface of a toroidal first preform to bond the two together. Stitching can be performed using a stitcher.

[0003] A typical stitcher includes a stitch roller that presses the second preform against the first preform, and a stitch cylinder (air cylinder) that holds the stitch roller. Stitchers that also include a rotating device that rotates the stitch cylinder during stitching have also been devised (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-12342 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the stitch cylinder is rotated during stitching, the stitch roller may move in a direction different from its normal movement direction and turn up the second preform. Therefore, an object of the present disclosure is to provide a stitcher in which the stitch roller is less likely to turn up the second preform when the stitch cylinder is rotated during stitching. [Means for solving the problem]

[0006] The present disclosure relates to a stitcher comprising: a stitch cylinder having a piston rod; a stitch roller attached to the piston rod and pressing a second preform against a first preform; a cylinder base that holds the stitch cylinder; and a rotating device that rotates the stitch cylinder relative to the cylinder base, wherein the cylinder base has a guide that guides the stitch cylinder so that the stitch cylinder rotates around a reference point that is the position of the tip of the stitch roller when the piston rod is in a predetermined reference position. [Effects of the Invention]

[0007] According to the stitcher of the present disclosure, when the stitch cylinder is rotated during stitching, the stitch roller is less likely to turn up the second pre-formed body. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front view of the stitcher. [Figure 2] FIG. 2 is a side view of the stitcher. [Figure 3] FIG. 3 is a diagram illustrating the stitching method. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Structure of the stitcher> The stitcher 100 according to this embodiment will be described below. The stitcher 100 presses a cylindrical second preform 102 against the outer peripheral surface of a toroidal first preform 101 to perform stitching to bond the two together. The first preform 101 of this embodiment is a so-called raw tire base (also called a tire intermediate), and the second preform 102 is a so-called tread ring (also called a tread member). Note that, hereinafter, the first preform 101 and the second preform 102 will be collectively referred to as preforms 110.

[0010] Fig. 1 is a front view of the stitcher 100. Fig. 2 is a side view of the stitcher 100 as viewed from the left side of the paper in Fig. 1. The left-right direction of the paper in Fig. 1 is the axial direction of the preform 110 (hereinafter referred to as the "tire axial direction"), and the up-down direction of the paper in Fig. 1 is the radial direction of the preform 110 (hereinafter referred to as the "tire radial direction"). In Fig. 2, the direction perpendicular to the paper surface is the tire axial direction, and the up-down direction of the paper surface is the tire radial direction.

[0011] The stitcher 100 of this embodiment is located near the top of the preform 110 (near the 12 o'clock position) when viewed from the tire axial direction (see FIG. 2). However, the position (circumferential position) of the stitcher 100 relative to the preform 110 is not limited. For example, the stitcher 100 may be located near the bottom end of the preform 110 (near the 6 o'clock position) when viewed from the tire axial direction. Furthermore, the stitchers 100 may be arranged corresponding to multiple circumferential positions of the preform 110.

[0012] 1, the stitcher 100 according to this embodiment includes a first unit 11 and a second unit 12 that are plane symmetrical to each other. The first unit 11 and the second unit 12 are symmetrical with respect to a plane that passes through the center of the tire axial direction (the so-called equator) of the preform 110 and is perpendicular to the tire axial direction. Note that the stitcher 100 may include only either the first unit 11 or the second unit 12.

[0013] The first unit 11 and the second unit 12 each include a stitch cylinder 20, a stitch roller 30, a cylinder base 40, a rotating device 50, and a radial driving device 60. The stitcher 100 also includes an axial driving device 70 that moves the first unit 11 and the second unit 12 in the tire axial direction. These components will be described in order below.

[0014] The stitch cylinder 20 is a device that holds the stitch roller 30. The stitch cylinder 20 is a so-called air cylinder. The stitch cylinder 20 has a tubular cylinder tube 21 and a piston rod 22 fixed to a piston that moves within the cylinder tube 21. The piston rod 22 is provided with a support shaft member 23 that extends in a direction perpendicular to the longitudinal direction of the piston rod 22. In addition, the piston rod 22 has two protrusions 25 that protrude toward the cylinder base 40 at a portion facing the cylinder base 40 (described later).

[0015] The stitch roller 30 is a member that comes into contact with the second preform 102 and presses the second preform 102 against the first preform 101. The stitch roller 30 is attached to the piston rod 22 via a support shaft member 23. The stitch roller 30 can rotate around an axis of rotation that extends in a direction perpendicular to the longitudinal direction of the piston rod 22. The stitch roller 30 of the first unit 11 and the stitch roller 30 of the second unit 12 are arranged to face each other.

[0016] The direction in which the stitch roller 30 presses the second preform 102 is the direction in which the piston rod 22 moves relative to the cylinder tube 21, i.e., the longitudinal direction of the stitch cylinder 20. The force with which the stitch roller 30 presses the second preform 102 (pressing force) is determined by the amount of air in the cylinder tube 21 and the position of the piston rod 22 relative to the cylinder tube 21 at the time of pressing. The amount of air in the cylinder tube 21 can be adjusted.

[0017] In this embodiment, the position of the tip of the stitch roller 30 when the piston rod 22 is in a predetermined reference position is defined as the "reference point 24." In other words, once the reference position is determined, the reference point is also determined. The reference position can be set arbitrarily. In this embodiment, the reference position is set to a position near the center of the movable range of the piston rod 22 where the pressing force of the stitch roller 30 is a predetermined reference pressing force.

[0018] When the reference position (reference point 24) is set in this manner, when the amount of air in the cylinder tube 21 is the same, if the position of the tip of the stitch roller 30 (the contact point between the stitch roller 30 and the second preform 102) is closer to the cylinder tube 21 than the reference point 24, the stitch roller 30 will press the second preform 102 with a pressing force greater than the reference pressing force, and if the position of the tip of the stitch roller 30 is farther from the cylinder tube 21 than the reference point 24, the stitch roller 30 will press the second preform 102 with a pressing force smaller than the reference pressing force.

[0019] The cylinder base 40 is a member that holds the stitch cylinder 20. In this embodiment, the cylinder base 40 is a fan-shaped plate material. However, the shape of the cylinder base 40 is not limited to this. The cylinder base 40 also has two guides 41. In this embodiment, the guides 41 are arc-shaped elongated holes centered on the reference point 24. A protrusion 25 fixed to the stitch cylinder 20 is inserted into each guide 41. As these protrusions 25 move along the guides 41, the stitch cylinder 20 rotates around the reference point 24.

[0020] As described above, the cylinder base 40 of this embodiment has two guides 41 that guide the stitch cylinder 20. However, the number of guides 41 is not limited to two and may be one. Also, although the guide 41 of this embodiment is an arc-shaped elongated hole, the guide 41 may also be an arc-shaped rail. In this case, the stitch cylinder 20 may be provided with a slider that moves along the rail instead of the protrusion 25.

[0021] The rotating device 50 rotates the stitch cylinder 20 relative to the cylinder base 40. The rotating device 50 has a rack gear 51, a pinion gear 52, and a pinion motor 53. The rack gear 51 is an arc-shaped gear centered on the reference point 24 and is fixed to the end of the cylinder base 40. The pinion gear 52 meshes with the rack gear 51 and moves along the rack gear 51 by rotating. The pinion motor 53 is a motor that rotates the pinion gear 52.

[0022] The pinion motor 53 is held by a connecting member 26 fixed to the stitch cylinder 20. In other words, the pinion gear 52 is connected to the stitch cylinder 20 via the pinion motor 53 and the connecting member 26. The rotation center of the pinion gear 52, the two protrusions 25, and the reference point 24 are aligned in a straight line. This arrangement allows the stitch cylinder 20 to rotate smoothly.

[0023] The radial drive device 60 is a device that moves the cylinder base 40 in the tire radial direction. As shown in Fig. 2, the radial drive device 60 has a radial drive screw rod 61 that extends in the tire radial direction, a radial drive nut 62 that is attached to the radial drive screw rod 61 and to which the cylinder base 40 is fixed, a radial drive motor 63 that rotates the radial drive screw rod 61, and a radial drive base 64 that holds the radial drive screw rod 61 and the radial drive motor 63.

[0024] When the radial drive motor 63 rotates the radial drive screw rod 61, the radial drive nut 62 moves in the tire radial direction along the radial drive screw rod 61. This causes the cylinder base 40 to move in the tire radial direction, and ultimately causes the stitch cylinder 20 and stitch roller 30 to move in the radial direction.

[0025] The axial drive device 70 is a device that moves the cylinder base 40 in the tire axial direction. By moving the cylinder base 40 in the tire axial direction, the first unit 11 and the second unit 12 as a whole move in the tire axial direction. As shown in FIG. 1 , the axial drive device 70 includes an axial drive threaded rod 71 that extends in the tire axial direction, an axial drive nut 72 that is attached to the axial drive threaded rod 71 and to which the radial drive base 64 of the radial drive device 60 is fixed, an axial drive motor 73 that rotates the axial drive threaded rod 71, and an axial drive base 74 that holds the axial drive threaded rod 71 and the axial drive motor 73.

[0026] When the axial drive motor 73 rotates the axial drive screw rod 71, the axial drive nut 72 moves in the tire axial direction along the axial drive screw rod 71. This causes the radial drive base 64 of the radial drive device 60 to move in the tire radial direction, and ultimately causes the cylinder base 40, stitch cylinder 20, and stitch roller 30 to move in the tire axial direction. When the axial drive screw rod 71 rotates in one direction, the axial drive nuts 72 of the first unit 11 and the second unit 12 move toward each other, and when the axial drive screw rod 71 rotates in the other direction, the axial drive nuts 72 of the first unit 11 and the second unit 12 move away from each other.

[0027] As described above, the stitcher 100 according to this embodiment is compact overall, yet is capable of moving the stitch cylinder 20 in the tire axial direction and tire radial direction, and of rotating the stitch cylinder 20 around the reference point 24.

[0028] <Stitching method> Next, a stitching method using the above-mentioned stitcher 100 will be described. As described above, stitching is a process of pressing the second preform 102 against the first preform 101 to pressure-bond the two together. Note that stitching is performed while rotating the preform 110 around its central axis. In this embodiment, the amount of air in the cylinder tube 21 is kept constant during stitching, but it may be varied.

[0029] Fig. 3 is a diagram illustrating a stitching method. Stitching is performed in the order of (a), (b), (c), and (d) in Fig. 3. Note that Fig. 3 only shows the operation of the first unit 11, but the second unit 12 also operates in the same manner as the first unit 11. Fig. 3 also shows cross sections of the first preformed body 101 and the second preformed body 102 when the second preformed body 102 is brought into close contact with the first preformed body 101.

[0030] 3, the second preform 102 includes a belt 103 formed of steel wire. In this embodiment, two belts 103 are stacked in the tire radial direction. In a cross-sectional view, the surface of the second preform 102 is linear near the center in the tire axial direction, but curved outside the ends of the belt 103 in the belt axial direction.

[0031] In the stitching method according to this embodiment, first, as shown in (a) of Fig. 3, the stitch roller 30 is brought into contact with the second preform 102, and in this state, the stitch cylinder 20 is moved from the center of the second preform 102 in the tire axial direction outward in the tire axial direction. The movement of the stitch cylinder 20 in the tire axial direction can be performed by the axial drive device 70 (see Fig. 1).

[0032] The stitch cylinder 20 is set at a position in the tire radial direction such that the reference point 24 coincides with the tip of the stitch roller 30 (the contact point between the stitch roller 30 and the second preform 102). As a result, the second preform 102 is pressed by the stitch roller 30 with a reference pressing force. The position of the stitch cylinder 20 in the tire radial direction can be adjusted by a radial drive device 60 (see FIG. 1). Furthermore, the stitch cylinder 20 is set at an angular position such that the longitudinal direction of the stitch cylinder 20 is perpendicular to the tire axial direction. As a result, the stitch roller 30 applies a force to the second preform 102 in a direction perpendicular to the surface.

[0033] 3(b), when the stitch roller 30 reaches the vicinity of the end of the belt 103 in the tire axial direction, the stitch cylinder 20 starts to rotate while moving outward in the tire axial direction. The direction of rotation of the stitch cylinder 20 is the direction in which the outer portion of the stitch cylinder 20 in the tire radial direction moves outward in the tire axial direction. By rotating the stitch cylinder 20 in this manner, a force is applied from the stitch roller 30 to the second preform 102 in a direction perpendicular to the surface or a direction close to this, even near the end of the belt 103 in the tire axial direction.

[0034] 3(c), even when the stitch roller 30 reaches a position axially outward of the end of the belt 103, the stitch cylinder 20 is continued to move axially outward while rotating. This allows the stitch roller 30 to apply a force to the second preform 102 in a direction perpendicular to the surface or in a direction close to this, even when the stitch roller 30 is axially outward of the end of the belt 103.

[0035] 3(d), when the stitch roller 30 reaches the vicinity of the end of the second preform 102, the stitch cylinder 20 is stopped from moving in the tire axial direction while continuing to rotate, and the stitch cylinder 20 is moved inward in the tire radial direction. This allows the stitch roller 30 to apply a force to the second preform 102 in a direction perpendicular to the surface or a direction close to this, even near the end of the second preform 102.

[0036] As described above, according to the stitching method of the present embodiment, a force is applied to the second preform body 102 in a direction perpendicular to the surface or in a direction close to this at all axial positions of the second preform body 102. This allows the second preform body 102 to be firmly pressed against the first preform body 101.

[0037] Furthermore, in this embodiment, the stitch cylinder 20 rotates around a reference point 24. If the stitch cylinder 20 were to rotate around a point near the center of the cylinder tube 21, the rotation of the stitch cylinder 20 would cause the stitch roller 30 to move in a direction different from its original direction (for example, a direction toward the center of the second preform 102 in the tire axial direction), which could result in the stitch roller 30 turning up the second preform 102. In contrast, in this embodiment, because the stitch cylinder 20 rotates around the reference point 24, the position of the tip of the stitch roller 30 remains almost unchanged, making it difficult for the stitch roller 30 to turn up the second preform 102.

[0038] Furthermore, in this embodiment, at least when the stitch cylinder 20 starts to rotate, the tip of the stitch roller 30 coincides with the reference point 24. Therefore, even when the stitch cylinder 20 starts to rotate, when force is likely to be applied to the second preformed body 102, the stitch roller 30 is unlikely to turn up the second preformed body 102.

[0039] However, the radial driver 60 may be controlled so that when the stitch roller 30 moves in contact with the surface of the second preformed body 102, the entire path of the tip of the stitch roller 30 coincides with the path of the reference point 24. In this case, the stitch roller 30 can always press the second preformed body 102 with an appropriate pressing force, and the second preformed body 102 is less likely to be turned up.

[0040] Furthermore, in this embodiment, the case where the second preform 102 is a tread ring has been described, but the second preform 102 may also be a member that forms a sidewall that is bonded to the side surface of the first preform 101.

[0041] In the tire manufacturing process, before the above-mentioned stitching is performed, the first preform 101 is expanded into a toroidal shape, and an annular second preform is joined to the outer peripheral surface of the first preform 101. Then, by performing the above-mentioned stitching on the joined first preform 101 and second preform 102, an uncrosslinked tire (also called a raw cover) made up of the first preform 101 and the second preform 102 is formed. Furthermore, by pressurizing and heating the formed uncrosslinked tire, the rubber contained in the first preform 101 and the second preform 102 undergoes a crosslinking reaction, and a tire is obtained.

[0042] <Summary> The present disclosure (1) is a stitcher comprising: a stitch cylinder having a piston rod; a stitch roller attached to the piston rod and pressing a second preform against a first preform; a cylinder base that holds the stitch cylinder; and a rotating device that rotates the stitch cylinder relative to the cylinder base, wherein the cylinder base has a guide that guides the stitch cylinder so that the stitch cylinder rotates around a reference point that corresponds to the position of the tip of the stitch roller when the piston rod is in a reference position.

[0043] The present disclosure (2) is the stitcher according to the present disclosure (1), wherein the guide is an arc-shaped slot centered on the reference point.

[0044] The present disclosure (3) is a stitcher according to the present disclosure (1) or (2), wherein the rotating device has an arc-shaped rack gear fixed to the cylinder base and centered on the reference point, a pinion gear connected to the stitch cylinder and moving along the rack gear, and a pinion motor that rotates the pinion gear.

[0045] The present disclosure (4) is a stitcher according to any one of the present disclosures (1) to (3), further comprising a radial drive device that moves the cylinder base in the tire radial direction of the first preform body, and an axial drive device that moves the cylinder base in the axial direction of the first preform body.

[0046] The present disclosure (5) is a stitching method for performing stitching using a stitcher described in any one of the present disclosures (1) to (4), wherein when the stitch roller moves while in contact with the surface of the second preform, all or part of the trajectory of the tip of the stitch roller coincides with the trajectory of the reference point.

[0047] The present disclosure (6) is the stitching method according to the present disclosure (5), wherein the tip of the stitch roller coincides with the reference point when the stitch cylinder starts to rotate.

[0048] The present disclosure (7) is a method for manufacturing a tire, which comprises joining the first preform and the second preform, pressing the second preform against the first preform using a stitcher described in any one of the present disclosures (1) to (4), to form an uncrosslinked tire, and then pressurizing and heating the formed uncrosslinked tire to obtain a tire. [Explanation of symbols]

[0049] 20 stitch cylinder 22 Piston rod 24 Reference points 25 Projection piece 30 Stitch Roller 40 Cylinder base 41 Guide 50 Rotating device 51 Rack Gear 52 Pinion gear 53 Pinion motor 60 Radial drive unit 70 Axial drive unit 100 Stitcher 101 First preform 102 Second preform

Claims

1. a stitch cylinder having a piston rod; a stitch roller attached to the piston rod and pressing a second preform against the first preform; a cylinder base for holding the stitch cylinder; a rotating device that rotates the stitch cylinder relative to the cylinder base, The cylinder base has a guide that guides the stitch cylinder so that the stitch cylinder rotates around a reference point that corresponds to the position of the tip of the stitch roller when the piston rod is in a reference position.

2. The stitcher according to claim 1 , wherein the guide is an arc-shaped slot centered on the reference point.

3. The rotation device is an arc-shaped rack gear fixed to the cylinder base and centered around the reference point; a pinion gear connected to the stitch cylinder and moving along the rack gear; 3. The stitcher of claim 1, further comprising: a pinion motor for rotating the pinion gear.

4. a radial direction driving device that moves the cylinder base in the radial direction of the first preform; 4. The stitcher according to claim 1, further comprising an axial drive device for moving said cylinder base in the axial direction of said first preform.

5. A stitching method for performing stitching using the stitcher according to any one of claims 1 to 4, comprising: A stitching method, wherein when the stitch roller moves in contact with the surface of the second preform, at least a portion of the trajectory of the tip of the stitch roller coincides with the trajectory of the reference point.

6. The stitching method according to claim 5, wherein the leading edge of the stitch roller coincides with the reference point when the stitch cylinder starts to rotate.

7. A method for manufacturing a tire, comprising: joining the first preform and the second preform; pressing the second preform against the first preform using the stitcher according to claim 1 to form an uncrosslinked tire; and pressurizing and heating the formed uncrosslinked tire to obtain a tire.

Images