Tread rubber forming method and tread rubber forming apparatus

Abstract

Provided are a tread rubber forming method and a tread rubber forming apparatus that can efficiently form a tread rubber including a conductive layer and three layers in a seamless manner. The tread rubber forming method (S1) includes: a first step of forming a base layer (1); a second step of forming a first intermediate layer (21) on a part of an outer peripheral surface of the base layer (1); a third step (S13) of layering and winding a third rubber strip (GS3) on an outer peripheral surface of the first intermediate layer (21), thereby forming a first cover layer (31); a fourth step (S14) of winding a fourth rubber strip (GS4) having conductivity from a position where the base layer (1) is in contact to an outer peripheral surface of the first cover layer (31) so as to form a conductive layer (4); and a fifth step of forming a second cover layer (32) on the radially outer side of the base layer (1) in such a manner that a part of the conductive layer (4) is exposed to the radially outer side of the tread rubber.

Description

Technical Field

[0001] This invention relates to a technique for forming a ring-shaped tread compound by spirally stacking and winding unvulcanized rubber strips. Background Technology

[0002] Currently, it is known that a technique for improving tire uniformity is formed by spirally layering and winding rubber strips to create a seamless tread compound (for example, see Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2005-35337 Summary of the Invention

[0004] Patent document 1 discloses a technique for forming tread compound in a seamless manner, wherein the tread compound includes a conductive strip that penetrates two rubber layers in the thickness direction.

[0005] However, in recent years, for example, in order to improve wet road performance, fuel efficiency and responsiveness in a balanced way, tread compounds consisting of three rubber layers are being studied.

[0006] However, in the technology described in the aforementioned Patent Document 1, it is difficult to form a tread compound containing three layers of rubber and conductive layer without seam.

[0007] The present invention is proposed in view of the above-described actual situation, and its main purpose is to provide a tread rubber forming method and tread rubber forming apparatus, which can form a tread rubber comprising a conductive layer and a three-layer rubber layer in a seamless manner.

[0008] The first invention is a method for forming a tread compound. This method involves spirally layering and winding an uncured rubber strip around the radially outer side of a cylindrical body to form an annular tread compound. The method includes: a first step of layering and winding a first rubber strip along the axial direction of the cylindrical body to form a base layer; a second step of layering and winding a non-conductive second rubber strip along the axial direction on the outer periphery of the base layer in a region on one side of the axial direction to form a first intermediate layer; and a third step of layering a non-conductive third rubber strip along the axial direction while simultaneously layering and winding the non-conductive third rubber strip around the outer periphery of the base layer. A third rubber strip is stacked and wound around the outer peripheral surface of the first intermediate layer, thereby forming a first cover layer; in the fourth step, a conductive fourth rubber strip is wound around the outer peripheral surface of the first cover layer from the position where it contacts the base layer in the region on the other side of the axial direction relative to the first intermediate layer and the first cover layer, thereby forming a conductive layer; and in the fifth step, while moving the third rubber strip along the axial direction in the region on the other side of the axial direction relative to the conductive layer, the third rubber strip is stacked and wound around the radially outer side of the base layer in such a way that a portion of the conductive layer is exposed on the radially outer side of the tread rubber, thereby forming a second cover layer.

[0009] In the tread rubber forming method of the first invention, it is preferable to include the following step between the fourth step and the fifth step: while moving the second rubber strip relative to the conductive layer in the region on the other side along the axial direction, the second rubber strip is laminated and wound around the base layer and the outer peripheral surface of the conductive layer in such a way that a portion of the conductive layer is exposed on the radially outer side of the second rubber strip, thereby forming a second intermediate layer.

[0010] In the tread rubber forming method of the first invention, preferably, in the second step, the second rubber strip is wound with a winding spacing larger than the width of the second rubber strip, thereby forming a separation portion that separates the second rubber strips adjacent in the axial direction, and in the fourth step, the fourth rubber strip is wound in the region containing the separation portion.

[0011] In the tread rubber forming method of the present invention, it is preferable that, in the fifth step, the third rubber strip is wound in the region containing the separation portion.

[0012] In the tread rubber forming method of the first invention, it is preferable that, in the second step, the second rubber strip is layered and wound in such a way that the end edge of the first intermediate layer on the other side of the axial direction is located on the other side relative to the equator of the tread rubber.

[0013] In the tread rubber forming method of the present invention, it is preferable that the axial length W2 of the first intermediate layer formed in the second step is 60% to 80% of the axial length W1 of the tread rubber.

[0014] The second invention is a method for forming a tread compound. This method forms an annular tread compound by spirally winding a strip of uncured rubber around the radially outer side of a cylindrical body. The method includes: a first step of moving a first rubber strip along the axial direction of the cylindrical body while simultaneously spirally winding the first rubber strip to form a base layer; a second step of moving a non-conductive second rubber strip along the axial direction while simultaneously spirally winding the non-conductive second rubber strip around the outer peripheral surface of the base layer in a region on one side of the axial direction to form a first intermediate layer; a third step of winding a conductive third rubber strip around the outer peripheral surface of the first intermediate layer from a position where it contacts the base layer in a region on the other side of the axial direction relative to the first intermediate layer to form a first conductive layer; and a fourth step of moving the second rubber strip along the axial direction relative to the first conductive layer in a region on the other side of the axial direction while simultaneously spirally winding the first rubber strip around the outer peripheral surface of the first intermediate layer. In a fifth step, a non-conductive fourth rubber strip is moved along the axial direction while being wound around the outer periphery of the first intermediate layer, thereby forming a first cover layer. In a sixth step, a third rubber strip is wound around the outer periphery of the first cover layer from the position where it contacts the first conductive layer in the region on the other side of the axial direction, thereby forming a second conductive layer. In a seventh step, a fourth rubber strip is moved along the axial direction in the region on the other side of the axial direction relative to the second conductive layer, while a portion of the second conductive layer is exposed radially out of the tread rubber, and the fourth rubber strip is wound around the outer periphery of the second intermediate layer and the second conductive layer, thereby forming a second cover layer.

[0015] The third invention is a tread compound forming apparatus that forms an annular tread compound by spirally winding uncured rubber strips. The tread compound forming apparatus includes: a first applicator that moves a first rubber strip along the axial direction of the tread compound while winding the first rubber strip in layers, thereby forming a base layer; a second applicator that moves a non-conductive second rubber strip along the axial direction while winding the non-conductive second rubber strip in layers around a region on one side of the axial direction on the outer peripheral surface of the base layer, thereby forming a first intermediate layer; a third applicator that moves a non-conductive third rubber strip along the axial direction while winding the non-conductive third rubber strip in layers around the outer peripheral surface of the first intermediate layer, thereby forming a first cover layer; and a fourth applicator that, relative to the first intermediate layer and the first cover layer, winds a conductive fourth rubber strip across the outer peripheral surface of the first cover layer from a position where it contacts the base layer, thereby forming a conductive layer.

[0016] In the tread rubber forming apparatus of the present third invention, preferably, the third applicator moves the third rubber strip along the axial direction relative to the conductive layer in a region on the other side of the axial direction, while the third rubber strip is layered and wound around the base layer and the radially outer side of the conductive layer in such a way that a portion of the conductive layer is exposed on the radially outer side of the tread rubber, thereby forming a second cover layer.

[0017] In the tread rubber forming apparatus of the third invention, preferably, the second applicator moves the second rubber strip along the axial direction relative to the conductive layer in a region on the other side of the axial direction, such that a portion of the conductive layer is exposed radially outward of the second rubber strip, thereby forming a second intermediate layer.

[0018] In the tread rubber forming apparatus of the present third invention, it is preferred to include: a pair of cylindrical bodies that are exclusively disposed at a first position or a second position; and a moving part that moves the cylindrical bodies to exchange the cylindrical bodies disposed at each position, wherein the first applicator and the second applicator are disposed at a position corresponding to the first position, and the third applicator and the fourth applicator are disposed at a position corresponding to the second position.

[0019] The fourth invention is a tread compound forming apparatus that forms an annular tread compound by spirally winding uncured rubber strips. The apparatus comprises: a first applicator that moves a first rubber strip along the axial direction of the tread compound while winding the first rubber strip in layers, thereby forming a base layer; a second applicator that moves a non-conductive second rubber strip along the axial direction while winding the non-conductive second rubber strip in layers around the outer periphery of the base layer, thereby forming an intermediate layer; a third applicator that winds a conductive third rubber strip from its contact with the base layer across the outer periphery of the intermediate layer, thereby forming a first conductive layer; a fourth applicator that moves a non-conductive fourth rubber strip along the axial direction while winding it in layers around the outer periphery of the intermediate layer, thereby forming a cover layer; and a fifth applicator that winds a conductive fifth rubber strip from its contact with the first conductive layer across the outer periphery of the cover layer, thereby forming a second conductive layer.

[0020] In the tread rubber forming apparatus of the fourth invention, preferably, the second applicator stacks and winds the second rubber strip on the outer peripheral surface of the base layer in a region on one side of the axial direction, thereby forming a first intermediate layer; the third applicator winds the third rubber strip across the outer peripheral surface of the first intermediate layer in a region on the other side of the axial direction relative to the first intermediate layer, thereby forming a first conductive layer; and the second applicator stacks and winds the second rubber strip on the base layer and the outer peripheral surface of the first conductive layer in such a way that a portion of the first conductive layer is exposed radially outward of the second rubber strip, thereby forming a second intermediate layer.

[0021] In the tread rubber forming apparatus of the fourth invention, preferably, the fourth applicator layers and winds the fourth rubber strip around a portion of the outer peripheral surface of the first intermediate layer, thereby forming a first cover layer; the fifth applicator winds the fifth rubber strip across the outer peripheral surface of the intermediate layer in a region on the opposite side of the axial direction relative to the first cover layer, thereby forming a second conductive layer; and the fourth applicator layers and winds the fourth rubber strip around the intermediate layer and the outer peripheral surface of the second conductive layer in such a way that a portion of the second conductive layer is exposed radially outward of the fourth rubber strip, thereby forming a second cover layer.

[0022] In the tread rubber forming apparatus of the present fourth invention, preferably, it includes: a pair of cylindrical bodies that are exclusively disposed at a first position or a second position; and a moving part that moves the cylindrical bodies to exchange the cylindrical bodies disposed at each position, wherein the first applicator to the third applicator are disposed at a position corresponding to the first position, and the fourth applicator and the fifth applicator are disposed at a position corresponding to the second position.

[0023] In the tread compound forming method of the first invention, the base layer is formed in the first step, and the first intermediate layer is formed in a portion of the outer periphery of the base layer in the second step. Furthermore, in the third step, the first cover layer is formed on the outer periphery of the first intermediate layer, and in the fourth step, the conductive layer is formed extending across the outer periphery of the first cover layer from the position where it contacts the base layer. Finally, in the fifth step, the second cover layer is formed such that a portion of the conductive layer is exposed radially outward from the tread compound. Therefore, the tread compound is formed seamlessly, and the tread compound includes the conductive layer and a three-layer rubber layer consisting of the base layer, the intermediate layer, and the cover layer.

[0024] In the tread compound forming method of the second invention, the base layer is formed in the first step, and the first intermediate layer is formed in a portion of the outer periphery of the base layer in the second step. Furthermore, in the third step, the first conductive layer is formed from the position in contact with the base layer and extending throughout the outer periphery of the first cover layer. In the fourth step, the second intermediate layer is formed such that a portion of the first conductive layer is exposed radially outward of the second rubber strip. Further, in the fifth step, a first cover layer is formed on the outer periphery of the first intermediate layer; in the sixth step, the second conductive layer is formed from the position in contact with the first conductive layer and extending throughout the outer periphery of the first cover layer; and in the seventh step, the second cover layer is formed such that a portion of the second conductive layer is exposed radially outward of the tread compound. Therefore, a seamless tread compound is formed, comprising the conductive layer and a three-layer rubber layer consisting of the base layer, the intermediate layer, and the cover layer.

[0025] In the tread compound forming apparatus of this third invention, the base layer is formed by the first applicator, and the first intermediate layer is formed on a portion of the outer periphery of the base layer by the second applicator. Furthermore, the first cover layer is formed on the outer periphery of the first intermediate layer by the third applicator, and the conductive layer is formed across the outer periphery of the first cover layer from the position in contact with the base layer by the fourth applicator. Then, the second cover layer is formed by the third applicator in such a way that a portion of the conductive layer is exposed radially outward from the tread compound. Therefore, the tread compound, comprising the conductive layer and a three-layer rubber layer consisting of the base layer, the intermediate layer, and the cover layer, is formed seamlessly.

[0026] In the tread compound forming apparatus of this fourth invention, the base layer is formed by the first applicator, and the first intermediate layer is formed on a portion of the outer periphery of the base layer by the second applicator. Furthermore, the first conductive layer is formed on the outer periphery of the first cover layer from the position in contact with the base layer by the third applicator, and the second intermediate layer is formed by the fourth applicator in such a way that a portion of the first conductive layer is exposed radially outward of the second rubber strip. Further, the first cover layer is formed on the outer periphery of the first intermediate layer by the fifth applicator, the second conductive layer is formed on the outer periphery of the first cover layer from the position in contact with the first conductive layer by the sixth applicator, and the second cover layer is formed by the seventh applicator in such a way that a portion of the second conductive layer is exposed radially outward of the tread compound. Therefore, a seamless tread compound is formed, comprising the conductive layer and a three-layer rubber layer consisting of the base layer, the intermediate layer, and the cover layer. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of the tread rubber formed by the tread rubber forming method and tread rubber forming apparatus of the present invention.

[0028] Figure 2 This is a front view showing a schematic structure of a tread rubber forming apparatus according to one embodiment of the present invention.

[0029] Figure 3 It is a conceptual representation of the use Figure 2 Cross-sectional views of the first and second steps of the tread rubber forming method of the tread rubber forming apparatus.

[0030] Figure 4 It is a conceptual representation of what follows. Figure 3 Cross-sectional views of the third and fourth processes.

[0031] Figure 5 It is a conceptual representation of what follows. Figure 4 A cross-sectional view of the fifth process, etc.

[0032] Figure 6 It is a conceptual representation Figure 3 Cross-sectional views of the first and second steps of a modified method for forming tread rubber.

[0033] Figure 7 It is a conceptual representation of what follows. Figure 6 Cross-sectional views of the third to fifth processes.

[0034] Figure 8 It is a conceptual representation Figure 3 Cross-sectional views of the first and second steps of other variations of the tread rubber forming method.

[0035] Figure 9 It is a conceptual representation of what follows. Figure 8 Cross-sectional views of the third to fifth processes.

[0036] Figure 10 It means Figure 2 A front view of a simplified structure of a modified example of a tread rubber forming device.

[0037] Figure 11 It is a conceptual representation of the use Figure 10 Cross-sectional views of the first to fourth steps of the tread rubber forming method of the tread rubber forming apparatus.

[0038] Figure 12 It is a conceptual illustration of what follows. Figure 11 Cross-sectional views of the fifth to seventh processes.

[0039] Figure 13 It means Figure 1 A cross-sectional view of a deformed example of tire tread rubber.

[0040] Figure 14 It is a conceptual representation used for formation Figure 13 A cross-sectional view of the tread rubber forming method.

[0041] Figure 15 It means Figure 1 A cross-sectional view of another variation of the tread rubber.

[0042] Figure 16 It is a conceptual representation used for formation Figure 15 A cross-sectional view of the tread rubber forming method.

[0043] Figure 17 It means Figure 2 A front view of the schematic structure of other variations of the tread rubber forming device.

[0044] Figure 18 It means Figure 2 A front view of the schematic structure of another variation of the tread rubber forming device.

[0045] Label Explanation

[0046] 1: Base layer; 2: Intermediate layer; 3: Covering layer; 4: Conductive layer; 10: Tread compound; 21: First intermediate layer; 22: Second intermediate layer; 23: Separation section; 31: First covering layer; 32: Second covering layer; 41: First conductive layer; 42: Second conductive layer; 100: Tread compound forming device; 100A: Tread compound forming device; 100B: Tread compound forming device; 100C: Tread compound forming device; 101: Cylindrical body; 102: Circular Cylinder; 111: First applicator; 112: Second applicator; 113: Third applicator; 114: Fourth applicator; GS1: First rubber strip; GS2: Second rubber strip; GS3: Third rubber strip; GS4: Fourth rubber strip; P1: First position; P2: Second position; S1: Tread rubber forming method; S11: First process; S12: Second process; S13: Third process; S14: Fourth process; S15: Fifth process. Detailed Implementation

[0047] Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

[0048] Figure 1 This is a cross-sectional view of the tread compound of a tire formed by the tread compound forming method and tread compound forming apparatus of this embodiment. The tread compound 10 is formed in a ring shape. The tread compound 10 is formed by spirally winding unvulcanized rubber strips.

[0049] The tread compound 10 has a three-layer structure, comprising: a base layer 1 located at the innermost periphery; an intermediate layer 2 located at the outer periphery of the base layer 1; and a cover layer 3 located at the outer periphery of the intermediate layer 2. The tread compound 10 also includes a conductive layer 4 that penetrates the base layer 1, the intermediate layer 2, and the cover layer 3 in the thickness direction.

[0050] The base layer 1 is constructed, for example, by emphasizing responsive performance. The intermediate layer 2 is constructed, for example, by emphasizing low fuel consumption performance.

[0051] The cover layer 3 is constructed, for example, by emphasizing wet road performance. Low fuel consumption and wet performance are achieved by incorporating a large amount of silica as a reinforcing agent (silica-rich rubber).

[0052] Silica-rich rubber typically possesses non-conductive properties. Hereinafter, in this application, the volume resistivity after vulcanization is defined as 1 × 10⁻⁶. 8Rubber materials with a resistance greater than Ωcm are designated as non-conductive rubber. Furthermore, the volume resistivity can be measured, for example, using a 15cm square rubber sample with a thickness of 2mm, under conditions of 500V applied voltage, 25°C temperature, and 50% humidity using a resistance meter.

[0053] The conductive layer 4 is achieved, for example, by using (carbon-rich) rubber with a large amount of carbon black as a reinforcing agent. Carbon-rich rubber generally has conductive properties. Hereinafter, in this application, the volume resistivity after vulcanization is 1×10⁻⁶. 7 Rubber materials with a strength of Ωcm or less are classified as conductive rubber.

[0054] The outer surface of the tread compound 10 is made conductive to the interior by means of a conductive layer 4 that penetrates through the intermediate layer 2 and the cover layer 3. Conductive rubber, such as the adhesive for the belt component or the sidewall rubber, is disposed radially inside the tread compound 10. Therefore, by forming the base layer 1 with conductive rubber, the outer surface of the tread compound 10 and the adhesive for the belt component are made conductive through the conductive layer 4 and the base layer 1, and the charge accumulated on the tire is released.

[0055] Figure 2 This describes an example of a tread forming apparatus 100 preferably suited to the present tread forming method. The tread forming apparatus 100 includes a cylindrical body 101 that serves as a substrate for forming the tread compound 10, and a first applicator 111, a second applicator 112, a third applicator 113, and a fourth applicator 114 for supplying rubber strips GS1, GS2, GS3, and GS4.

[0056] In addition to forming the drum for the tread compound 10, the cylindrical body 101 can also be used as a shell constituting the main part of the green tire (structures other than the tread portion). A belt layer or a crown belt layer can be formed on the outer circumferential surface of the cylindrical body. Alternatively, a rigid core can also be used with the cylindrical body. In this case, a carcass layer, belt layer, and crown belt layer are formed on the outer surface of the rigid core, and the tread compound 10 is formed on its outer circumferential surface. In this application, for ease of explanation, one side (to the left in the figure) of the axial direction of the cylindrical body 101 (the axial direction of the tread compound 10) is designated as the second axial direction D2, and the other side as the first axial direction D1. Alternatively, the other side of the axial direction of the cylindrical body 101 can be designated as the second axial direction D2, and one side as the first axial direction D1.

[0057] The first applicator 111 to the fourth applicator 114 are positioned corresponding to the cylindrical body 101. The positions corresponding to the cylindrical body 101 refer to the positions where rubber strips GS1, GS2, GS3 and GS4 can be supplied to the cylindrical body 101.

[0058] In the tread rubber forming apparatus 100, tread rubber 10 is formed by winding rubber strips GS1, GS2, GS3 and GS4 around the radially outer side of the rotating cylindrical body 101.

[0059] The first applicator 111 to the fourth applicator 114 are configured to move along the axial direction of the cylindrical bodies 101 and 102. The cylindrical bodies 101 and 102 may also be configured to move along their axial direction. In addition, the first applicator 111 to the fourth applicator 114 may also be configured as needed to move in a forward-backward direction perpendicular to the axial direction of the cylindrical bodies 101 and 102.

[0060] The first applicator 111 to the fourth applicator 114, etc., can use a known rubber strip supply device. For example, the first applicator 111 can be composed of a device having a belt for conveying the first rubber strip GS1 and rollers for pressing the wound portion of the first rubber strip GS1 radially inward toward the cylindrical body 101. The structure of the second applicator 112 to the fourth applicator 114, etc., is also the same as that of the first applicator 111.

[0061] The rotation of the cylindrical bodies 101 and 102, and the movement of the first applicator 111 and the cylindrical bodies 101 and 102 are controlled by a control unit (not shown). The control unit provides synchronous control for the first applicator 111 and the cylindrical bodies 101 and 102. Hereinafter, the method in which the first applicator 111 and the like can move axially will be described, but the same applies to the method in which the cylindrical bodies 101 and 102 can move axially.

[0062] The first applicator 111 supplies a first rubber strip GS1 that forms the base layer 1. The first rubber strip GS1 is configured with conductive properties. Therefore, the conductive layer 4 is connected to the adhesive of the belt component and the sidewall rubber through the base layer 1, and the charge accumulated in the tire is released.

[0063] The second applicator 112 supplies a second rubber strip GS2 that forms the intermediate layer 2. The second rubber strip GS2 is composed of a non-conductive material.

[0064] The third applicator 113 supplies a third rubber strip GS3 that constitutes the covering layer 3. The third rubber strip GS3 is composed of a non-conductive mating material. The fourth applicator 114 supplies a fourth rubber strip GS4 that constitutes the conductive layer 4. The fourth rubber strip GS4 is composed of a conductive mating material.

[0065] Figures 3 to 5 The steps of this tread rubber forming method S1 are shown in time sequence. This tread rubber forming method S1 includes steps S11 through S15. Hereinafter, refer to... Figures 3 to 5 The case where the tread compound 10 is formed using a cylindrical body 101 will be explained, but the same applies to the case where the tread compound 10 is formed using a cylindrical body 102 (in addition, in the following...). Figures 6 to 13 (The same applies to China).

[0066] like Figure 3As shown, in the first process S11, the first applicator 111 moves the first rubber strip GS1 along the axial direction of the cylindrical body 101 while simultaneously layering and winding the first rubber strip GS1 around the outer circumferential surface of the cylindrical body 101. Through the first process S11, a base layer 1 is formed along the outer circumferential surface of the cylindrical body 101.

[0067] Alternatively, before the first step S11, the belted fabric layer and / or the seamless crown band can be wound around the outer circumferential surface of the cylindrical body 101. In this case, the first rubber strip GS1 is layered and wound around the outer circumferential surface of the belted fabric layer and / or the seamless crown band (the same applies in the first steps S21, S31 and S41 described later).

[0068] In the second process S12, the second applicator 112 moves the second rubber strip GS2 along the axial direction of the cylindrical body 101 while simultaneously layering and winding the second rubber strip GS2 onto a portion of the outer peripheral surface of the base layer 1 (on the outer peripheral surface of the base layer, on one side of the axial direction). Figure 3 The region in the middle (approximately the right half of the first axial direction D1 side) is formed along the outer periphery of the base layer 1 through the second process S12. The first intermediate layer 21 constitutes a part of the intermediate layer 2.

[0069] like Figure 4 As shown, in the third step S13, the third applicator 113 moves the third rubber strip GS3 along the axial direction of the cylindrical body 101 while simultaneously winding the third rubber strip GS3 onto the outer peripheral surface of the first intermediate layer 21. Through the third step S13, a first cover layer 31 is formed along the outer peripheral surface of the first intermediate layer 21. The first cover layer 31 constitutes a portion of the cover layer 3.

[0070] In the fourth step S14, the fourth applicator 114 winds the fourth rubber strip GS4. The fourth rubber strip GS4, relative to the first intermediate layer 21 and the first cover layer 31, is wound across the outer periphery of the first cover layer 31 from the position where it contacts the base layer 1 in the region on the other side of the axial direction of the cylindrical body 101, i.e., the second axial direction D2 side. Through the fourth step S14, a conductive layer 4 is formed that makes the tread surface of the tire tread connected to the interior. Furthermore, in the fourth step S14, it is preferable that the fourth applicator 114 moves along the axial direction of the cylindrical body 101. As a result, the conductive layer 4 is formed neatly and uniformly along the outer periphery of the first intermediate layer 21 and the first cover layer 31 without wrinkles or ripples.

[0071] like Figure 5 As shown, in process S14B, the second applicator 112 moves the second rubber strip GS2 along the axial direction of the cylindrical body 101 while simultaneously layering and winding the second rubber strip GS2 around the outer periphery of the base layer 1 and the conductive layer 4. The second rubber strip GS2 is layered and wound relative to the conductive layer 4 on one side of the second axial direction D2 (in... Figure 5The middle section is roughly the left half, i.e., the area where the second rubber strip GS2 was not laminated and wound in the second step S12. The second rubber strip GS2 is laminated and wound in such a way that a portion of the conductive layer 4 is exposed radially outward from the second rubber strip GS2. Through step S14B, a second intermediate layer 22 is formed. The second intermediate layer 22 constitutes a portion of the intermediate layer 2.

[0072] In the fifth step S15, the third applicator 113 moves the third rubber strip GS3 axially while simultaneously layering and wrapping the third rubber strip GS3 around the radial outer side of the base layer 1 (in... Figure 5 (The middle layer is the outer peripheral surface of the second intermediate layer 22). The third rubber strip GS3 is layered and wound relative to the conductive layer 4 on the second axial direction D2 side in such a way that a portion of the conductive layer 4 is exposed radially outward from the tread rubber 10. A second cover layer 32 is formed through the fifth step S15. The second cover layer 32 constitutes a portion of the cover layer 3.

[0073] In this tread compound forming method S1, a base layer 1 is formed in the first step S11, and a first intermediate layer 21 is formed locally on the outer periphery of the base layer 1 in the second step S12. Then, in the third step S13, a first cover layer 31 is formed on the outer periphery of the first intermediate layer 21. In the fourth step S14, a conductive layer 4 is formed from the position where it contacts the base layer 1 and extends throughout the outer periphery of the first cover layer 31. In the fifth step S15, a second cover layer 32 is formed such that a portion of the conductive layer 4 is exposed radially outward of the tread compound 10. Therefore, the tread compound 10 is constructed seamlessly, and the tread compound 10 includes the conductive layer 4 and a three-layer rubber layer consisting of the base layer 1, the intermediate layer 2, and the cover layer 3.

[0074] Furthermore, by forming a second intermediate layer 22 between the base layer and the first cover layer 31 in process S14B, the low fuel consumption performance can be easily improved.

[0075] Similarly, in this tread compound forming apparatus 100, a base layer 1 is formed by a first applicator 111, and a first intermediate layer 21 is formed locally on the outer periphery of the base layer 1 by a second applicator 112. Furthermore, a first cover layer 31 is formed on the outer periphery of the first intermediate layer 21 by a third applicator 113, and a conductive layer 4 is formed from the position where it contacts the base layer 1, extending across the outer periphery of the first cover layer 31 by a fourth applicator 114. Finally, a second cover layer 32 is formed by the third applicator 113 such that a portion of the conductive layer 4 is exposed radially outward from the tread compound 10. Therefore, the tread compound 10 is formed seamlessly, and this tread compound 10 includes the conductive layer 4 and a three-layer rubber layer consisting of the base layer 1, the intermediate layer 2, and the cover layer 3.

[0076] In the second process S12 to the fourth process S14, it is preferable to stack and wind the second rubber strip GS2, the third rubber strip GS3, and the fourth rubber strip GS4 in the same direction. Figure 3 as well as Figure 4 In the example, the second rubber strip GS2, the third rubber strip GS3, and the fourth rubber strip GS4 are stacked and wound from the beginning of the second axial direction D2 toward the first axial direction D1. The second rubber strip GS2, the third rubber strip GS3, and the fourth rubber strip GS4 can also be stacked and wound from the beginning of the first axial direction D1 toward the second axial direction D2.

[0077] In this way, by aligning the winding directions of the second rubber strip GS2, the third rubber strip GS3, and the fourth rubber strip GS4, they can be wound simultaneously, at least partially. For example, the third step S13 can begin before the winding of the second rubber strip GS2 in the second step S12 is completed, to begin winding the third rubber strip GS3. Furthermore, the fourth step S14 can begin before the winding of the second rubber strip GS2 and the third rubber strip GS3 in the second step S12 and the third step S13 is completed, to begin winding the fourth rubber strip GS4. Therefore, the time required to form the tread compound 10 can be shortened, and tire production efficiency can be easily improved.

[0078] In steps S14B and S15, it is preferable that the second rubber strip GS2 and the third rubber strip GS3 are layered and wound in the same direction. Figure 5 In the example, the second rubber strip GS2 and the third rubber strip GS3 are stacked and wound from the beginning on the second axial direction D2 towards the first axial direction D1. The second rubber strip GS2 and the third rubber strip GS3 can also be stacked and wound from the beginning on the first axial direction D1 towards the second axial direction D2.

[0079] By aligning the winding directions of the second rubber strip GS2 and the third rubber strip GS3, the second rubber strip GS2 and the third rubber strip GS3 can be wound simultaneously, at least partially. For example, the fifth step S15 can begin before the winding of the second rubber strip GS2 in step S14B, thereby shortening the time required to form the tread compound 10.

[0080] In addition, in process S14B, the second rubber strip GS2 can be layered and wound from the beginning of the second axial direction D2 towards the first axial direction D1. Process S14B is started before the winding of the first rubber strip GS1 to the fourth rubber strip GS4 in the first process S11 to the fourth process S14 is completed, and the winding of the second rubber strip GS2 can be started, which can shorten the time required to form the tread rubber 10.

[0081] Figures 6 to 7The steps of tread compound forming method S2, a variation of tread compound forming method S1, are shown in chronological order. This tread compound forming method S2 is performed by a tread compound forming apparatus 100. This tread compound forming method S2 includes steps S21 through S25.

[0082] like Figure 6 As shown, in the first process S21, with Figure 3 The first process S11 shown also involves layering and winding the first rubber strip GS1 to form a base layer 1 along the outer circumferential surface of the cylindrical body 101.

[0083] In the second process S22, the second applicator 112 moves the second rubber strip GS2 along the axial direction of the cylindrical body 101 while simultaneously layering and winding the second rubber strip GS2 onto a portion of the outer peripheral surface of the base layer 1. Figure 6 (The area excluding the separation section 23). Through the second process S22, the first intermediate layer 21 is formed along the outer peripheral surface of the base layer 1.

[0084] In the second process S22, a discontinuous first intermediate layer 21 is formed along the axial direction of the cylindrical body 101. In the discontinuous region of the first intermediate layer 21, the second rubber strip is wound with a winding spacing greater than the width of the second rubber strip GS2. As a result, two first intermediate layers 21 are formed on the radially outer side of the base layer 1, and a separation portion 23 is formed between the first intermediate layers 21 to separate the axially adjacent second rubber strips GS2.

[0085] like Figure 7 As shown, in the third step S23, in conjunction with Figure 4 The third rubber strip GS3 is layered and wound in the same manner as the third process S13 shown, forming a first covering layer 31 along the outer peripheral surface of the first intermediate layer 21 on the first axial direction D1 side.

[0086] In the fourth process S24, with Figure 4 The fourth step S14, as shown, similarly winds the fourth rubber strip GS4 to form a conductive layer 4 that makes the tread surface of the tire tread connected to the interior. The fourth rubber strip GS4 is wound in the area including the separation portion 23. Thus, the conductive layer 4 is formed throughout the outer peripheral surface of the first cover layer 31, starting from the position where it contacts the base layer 1.

[0087] In the fifth process S25, with Figure 5 The third rubber strip GS3 is layered and wound in the same manner as in the fifth process S15 shown. The third rubber strip GS3 is wound in the region containing the separation portion 23. As a result, a second cover layer 32 is formed along the outer peripheral surfaces of the first intermediate layer 21, the base layer 1, and the conductive layer 4.

[0088] In the tread compound forming method S2, the tread compound 10 is formed in a seamless manner. The tread compound 10 includes a conductive layer 4 and a three-layer rubber layer consisting of a base layer 1, an intermediate layer 2 and a cover layer 3.

[0089] The preferred winding directions of the second rubber strip GS2, the third rubber strip GS3, and the fourth rubber strip GS4 in the second step S22 to the fifth step S25 of the tread rubber forming method S2 are the same as the preferred winding directions of the second rubber strip GS2, the third rubber strip GS3, and the fourth rubber strip GS4 in the second step S12 to the fifth step S15 of the tread rubber forming method S1.

[0090] Figures 8 to 9 The steps of tread rubber forming method S3, another variation of tread rubber forming method S1, are shown in time sequence. This tread rubber forming method S3 is performed by tread rubber forming apparatus 100. This tread rubber forming method S3 includes the first step S31 to the fifth step S35.

[0091] like Figure 8 As shown, in the first process S31, with Figure 3 The first process S11 shown also involves layering and winding the first rubber strip GS1 to form a base layer 1 along the outer circumferential surface of the cylindrical body 101.

[0092] In the second process S32, with Figure 3 The second process S12 shown also involves layering and winding the second rubber strip GS2 to form a first intermediate layer 21 along the outer periphery of the base layer 1.

[0093] In the second process S32, the second rubber strip GS2 is layered and wound in such a way that the end edge 21e on the second axial D2 side of the first intermediate layer 21 is located on the second axial D2 side relative to the equator CL of the tread rubber 10.

[0094] like Figure 9 As shown, in the third process S33, with Figure 4 The third process S13 shown also involves layering and winding the third rubber strip GS3 to form the first covering layer 31 along the outer periphery of the first intermediate layer 21.

[0095] In the fourth process S34, with Figure 4 The fourth step S14 shown also involves winding the fourth rubber strip GS4. As a result, a conductive layer 4 is formed from the position where it contacts the base layer 1, extending across the outer periphery of the first covering layer 31, making the tread surface of the tire tread connected to the interior.

[0096] In the fifth process 35, with Figure 5The third rubber strip GS3 is layered and wound in the same manner as in the fifth process S15 shown. The third rubber strip GS3 is wound from the outer peripheral surface of the base layer 1 to the outer peripheral surface of the conductive layer 4. Thus, a second cover layer 32 is formed along the outer peripheral surfaces of the base layer 1 and the conductive layer 4.

[0097] In the tread compound forming method S3, the tread compound 10 is formed efficiently in a seamless manner. The tread compound 10 includes a conductive layer 4 and a three-layer rubber layer consisting of a base layer 1, an intermediate layer 2 and a cover layer 3.

[0098] The axial length W2 of the first intermediate layer 21 formed in the second process S32 (refer to...) Figure 8 The preferred axial length W1 of the tread compound 10 is (refer to...) Figure 9 The length W2 is 60% to 80% of the length W1. By making the length W2 more than 60% of the length W1, the rubber volume of the first intermediate layer 21 increases, and the low fuel consumption performance of the tire using the tread compound 10 is improved. On the other hand, by making the length W2 less than 80% of the length W1, the conductive layer 4 is exposed from the tread surface near the equator CL of the tread compound 10, and the conductivity is improved.

[0099] The preferred winding directions of the second rubber strip GS2, the third rubber strip GS3, and the fourth rubber strip GS4 in the second step S32 to the fifth step S35 of the tread rubber forming method S3 are the same as the preferred winding directions of the second rubber strip GS2, the third rubber strip GS3, and the fourth rubber strip GS4 in the second step S12 to the fifth step S15 of the tread rubber forming method S1.

[0100] Figure 10 This refers to a modified example of the tread rubber forming apparatus 100A. The structure of the tread rubber forming apparatus 100 described above can be used for the following parts of the tread rubber forming apparatus 100A not described herein.

[0101] The tread compound forming apparatus 100A includes: a cylindrical body 101 that serves as a substrate for forming the tread compound 10; and a first applicator 111A, a second applicator 112A, a third applicator 113A, and a fourth applicator 114A for supplying rubber strips GS1A, GS2A, GS3A, and GS4A.

[0102] The first applicator 111A supplies a first rubber strip GS1A forming the base layer 1. The first rubber strip GS1A is formed by a non-conductive fit, similar to the first rubber strip GS1. The second applicator 112A supplies a second rubber strip GS2A forming the intermediate layer 2. The second rubber strip GS2A is formed by a non-conductive fit, similar to the second rubber strip GS2. The third applicator 113A supplies a third rubber strip GS3A forming the conductive layer 4. The third rubber strip GS3A is formed by a conductive fit, similar to the fourth rubber strip GS4.

[0103] The fourth applicator 114A supplies the fourth rubber strip GS4A, which constitutes the cover layer 3. The fourth rubber strip GS4A is made of the same non-conductive material as the third rubber strip GS3.

[0104] Figures 11 to 12 The steps of tread compound forming method S4, another variation of tread compound forming method S1, are shown in chronological order. This tread compound forming method S4 is performed by tread compound forming apparatus 100A. This tread compound forming method S4 includes steps S41 to S47.

[0105] like Figure 11 As shown, in the first step S41, the first applicator 111A moves the first rubber strip GS1A along the axial direction of the cylindrical body 101 while simultaneously layering and winding the first rubber strip GS1A. Through the first step S41, a base layer 1 is formed along the outer circumferential surface of the cylindrical body 101.

[0106] In the second step S42, the second applicator 112A moves the second rubber strip GS2A along the axial direction of the cylindrical body 101 while simultaneously layering and winding the second rubber strip GS2A onto a portion of the outer peripheral surface of the base layer 1. Through the second step S42, a first intermediate layer 21 is formed along the outer peripheral surface of the base layer 1.

[0107] In the third step S43, the third applicator 113A winds the third rubber strip GS3A relative to the first intermediate layer 21 on the second axial direction D2 side of the cylindrical body 101. The third rubber strip GS3A is wound all over the outer peripheral surface of the first intermediate layer 21 from the position where it contacts the base layer 1. Through the third step S43, a first conductive layer 41 is formed inside the tread portion. The first conductive layer 41 constitutes a portion of the conductive layer 4.

[0108] In the fourth step S44, the second applicator 112A moves the second rubber strip GS2A relative to the first conductive layer 41 along the axial direction of the cylindrical body 101 on the second axial direction D2 side, while simultaneously layering and winding the second rubber strip GS2A onto the base layer 1 and the outer peripheral surface of the first conductive layer 41. In the fourth step S44, the second rubber strip GS2A is layered and wound in such a way that a portion of the first conductive layer 41 is exposed radially outward from the second rubber strip GS2A. Through the fourth step S44, a second intermediate layer 22 is formed along the outer peripheral surface of the base layer 1.

[0109] In the fifth step S45, the fourth applicator 114A moves the fourth rubber strip GS4A along the axial direction of the cylindrical body 101 while simultaneously layering and winding the fourth rubber strip GS4A around the outer peripheral surface of the first intermediate layer 21. In the fifth step S45, the fourth rubber strip GS4A is layered and wound to avoid the outer peripheral surface of the first conductive layer 41. This maintains the exposure of the outer peripheral surface of the first conductive layer 41. Through the fifth step S45, the first cover layer 31 is formed along the outer peripheral surface of the first intermediate layer 21.

[0110] In the sixth step S46, the third applicator 113A wraps the third rubber strip GS3A relative to the first cover layer 31 around the second axial direction D2 side of the cylinder. The third rubber strip GS3A is wrapped around the outer peripheral surface of the first cover layer 31 in such a way that it protrudes radially outward from the position where it contacts the first conductive layer 41. Through the sixth step S46, a second conductive layer 42 is formed on the tread surface exposed on the tread. The second conductive layer 42 constitutes a portion of the conductive layer 4.

[0111] The first conductive layer 41 and the second conductive layer 42 are in contact inside the tread compound 10. Therefore, through the first conductive layer 41 and the second conductive layer 42, a conductive layer 4 is formed that makes the tread surface of the tread area conductive with the base layer 1.

[0112] In the seventh step S47, the fourth applicator 114A moves the fourth rubber strip GS4A relative to the second conductive layer 42 along the axial direction D2 of the cylinder 101 while simultaneously layering and winding the fourth rubber strip GS4A. The fourth rubber strip GS4A is wound around the outer peripheral surface of the second intermediate layer 22 and the second conductive layer 42 such that a portion of the second conductive layer 42 is exposed radially outward from the tread rubber 10. Through the seventh step S47, the second cover layer 32 is formed along the outer peripheral surface of the second intermediate layer 22.

[0113] Figure 13 This refers to tread compound 10B, a modified example of tread compound 10. Tread compound 10B is configured such that the conductive layer 4 penetrates the base layer 1 and reaches the inner circumferential surface of tread compound 10B. Therefore, in tread compound 10B, the first rubber strip GS1 used to form the base layer 1 can be constructed using a non-conductive compound.

[0114] The tread compound 10B is formed by the tread compound forming device 100 or the tread compound forming device 100A.

[0115] Figure 14 This describes a tread compound forming method S5 for forming a tread compound 10B with a structure that penetrates the base layer 1 to form a conductive layer 4. The tread compound forming method S5 is performed by a tread compound forming apparatus 100 or a tread compound forming apparatus 100A.

[0116] The following describes how tread rubber forming method S5 is performed using tread rubber forming apparatus 100A. However, when using tread rubber forming apparatus 100, it can also be performed by appropriately replacing rubber strips, etc. Tread rubber forming method S5 includes steps S51 to S54.

[0117] like Figure 14 As shown, in process S51, the first applicator 111A moves the first rubber strip GS1A along the axial direction of the cylindrical body 101 while simultaneously layering and winding the first rubber strip GS1A onto a portion of the outer circumferential surface of the cylindrical body 101 (in... Figure 14 On the area roughly the right half of the cylinder 101. Through process S53, a first base layer 11 is formed along the outer circumferential surface of the cylinder 101.

[0118] In step S52, the third applicator 113A winds the third rubber strip GS3A around the first base layer 11 on the second axial direction D2 side of the cylindrical body 101. The third rubber strip GS3A is wound all over the outer peripheral surface of the first base layer 11, starting from the position where it contacts the outer peripheral surface of the cylindrical body 101. Through step S52, a conductive layer 40 is formed inside the tread portion. The conductive layer 40 constitutes a portion of the conductive layer 4.

[0119] In step S53, the first applicator 111A moves the first rubber strip GS1A relative to the conductive layer 40 along the axial direction of the cylindrical body 101 on the second axial direction D2 side, while simultaneously layering and winding the first rubber strip GS1A around the outer circumferential surface of the cylindrical body 101. In step S53, the first rubber strip GS1A is layered and wound in such a way that a portion of the conductive layer 40 is exposed radially outward from the first rubber strip GS1A. Through steps S51 to S53, a base layer 1 and a conductive layer 4 penetrating the base layer 1 are formed.

[0120] Then, in step S54, the first intermediate layer 21, the first conductive layer 41, the second intermediate layer 22, the first cover layer 31, the second conductive layer 42 and the second cover layer 32 are formed in the same manner as in the tread rubber forming method S5.

[0121] Figure 15This refers to a tread compound 10C, which is another variation of the tread compound 10. The tread compound 10C is configured such that the intermediate layer 2 and the conductive layer 4 penetrate the base layer 1 and reach the inner circumferential surface of the tread compound 10C. Therefore, in the tread compound 10C, the first rubber strip GS1 used to form the base layer 1 can also be constructed using a non-conductive compound. The tread compound 10C can also be configured such that only the conductive layer 4 penetrates the base layer 1 and reaches the inner circumferential surface of the tread compound 10C.

[0122] The tread compound 10C is formed by the tread compound forming device 100 or the tread compound forming device 100A.

[0123] Figure 16 This describes a tread compound forming method S6 for forming a tread compound 10C that penetrates the base layer 1, comprising an intermediate layer 2 and a conductive layer 4. The tread compound forming method S6 is performed by a tread compound forming apparatus 100 or a tread compound forming apparatus 100A.

[0124] The following describes how tread rubber forming method S6 is performed using tread rubber forming apparatus 100A. However, when using tread rubber forming apparatus 100, it can also be performed by appropriately replacing rubber strips, etc. Tread rubber forming method S6 includes steps S61 to S64.

[0125] like Figure 16 As shown, in step S61, the first applicator 111A moves the first rubber strip GS1A along the axial direction of the cylindrical body 101 while simultaneously winding the first rubber strip GS1A onto the outer circumferential surface of the cylindrical body 101. In step S61, a discontinuous first base layer 11 and a second base layer 12 are formed along the axial direction of the cylindrical body 101. In the region where the first base layer 11 and the second base layer 12 are discontinuous, the first rubber strip GS1A is wound with a winding spacing greater than the width of the first rubber strip GS1A. Thus, the first base layer 11 and the second base layer 12 are formed on the radially outer side of the cylindrical body 101, and a separating portion 13 is formed between the first base layer 11 and the second base layer 12, which separates adjacent first rubber strips GS1A along the axial direction of the cylindrical body 101. The base layer 1 is composed of the first base layer 11 and the second base layer 12.

[0126] In step S62, the second applicator 112A moves the second rubber strip GS2A along the axial direction of the cylindrical body 101 while simultaneously winding the second rubber strip GS2A onto the outer peripheral surface of the first base layer 11. Through step S62, a first intermediate layer 21 is formed along the outer peripheral surface of the first base layer 11.

[0127] In the subsequent process S63, the first conductive layer 41, the second intermediate layer 22, the first cover layer 31, the second conductive layer 42 and the second cover layer 32 are formed in the same manner as in the tread rubber forming method S4.

[0128] Figure 17 The diagram shows a modified example of the tread rubber forming apparatus 100B. The structure of the tread rubber forming apparatus 100 described above can be used for the following undescribed parts of the tread rubber forming apparatus 100B.

[0129] The tread compound forming apparatus 100B includes: a pair of cylindrical bodies 101 and 102, which serve as the substrate for forming the tread compound 10; and a first applicator 111, a second applicator 112, a third applicator 113 and a fourth applicator 114, which are used to supply rubber strips GS1, GS2, GS3 and GS4.

[0130] In this embodiment, the cylindrical bodies 101 and 102 are arranged side by side and configured to rotate about the rotation axis 103. The movement of the cylindrical bodies 101 and 102 is not limited to rotation. For example, they can also slide along the axial direction or radially perpendicular to the axial direction. In this case, the rotational movement of the cylindrical bodies 101 and 102, described later, is replaced by a sliding movement.

[0131] Cylindrical bodies 101 and 102 are exclusively positioned at either the first position P1 or the second position P2. Figure 17 In the configuration, cylindrical body 101 is located at the first position P1, and cylindrical body 102 is located at the second position P2. The tread rubber forming apparatus 100 has a moving part 104 for moving the cylindrical bodies 101 and 102.

[0132] The moving part 104 moves the cylindrical bodies 101 and 102, allowing them to interchange their positions P1 and P2. More specifically, the moving part 104 drives the rotating shaft 103 to rotate the cylindrical bodies 101 and 102. Figure 17 For example, when rotated 180°, cylinder 101 is in the second position P2, and cylinder 102 is in the first position P1. Furthermore, when cylinders 101 and 102 rotate 180° (-180°), they return to their original positions. Figure 17 The rotation angle of the cylinders 101 and 102 is not limited to 180° and can be changed according to the specifications of the tread rubber forming device 100.

[0133] The first applicator 111 to the fourth applicator 114 are configured to move along the axial direction of the cylindrical bodies 101 and 102. The cylindrical bodies 101 and 102 may also be configured to move along their axial direction. In addition, the first applicator 111 to the fourth applicator 114 may also be configured to move in a forward-backward direction perpendicular to the axial direction of the cylindrical bodies 101 and 102, as needed.

[0134] The rotation of the cylindrical bodies 101 and 102, which is moved by the moving part 104, is controlled by the control part. The control part performs synchronous control on the first applicator 111, the cylindrical bodies 101 and 102, and the moving part 104. Hereinafter, the method in which the first applicator 111 can move axially will be described, but the method in which the cylindrical bodies 101 and 102 can move axially will also be described.

[0135] The first applicator 111 and the second applicator 112 are positioned at a location corresponding to the first position P1. "Positioned at a location corresponding to the first position P1" means that they are positioned to supply a rubber strip to the cylindrical body 101 or cylindrical body 102 located at the first position P1.

[0136] The third applicator 113 and the fourth applicator 114 are positioned at a location corresponding to the second position P2. "Positioned at a location corresponding to the second position P2" means that they are positioned to supply a rubber strip to the cylindrical body 102 or cylindrical body 101 located at the second position P2.

[0137] With the above-described configuration of the first applicator 111 to the fourth applicator 114, rubber strips can be wound simultaneously at the first position P1 and the second position P2. For example, the first rubber strip GS1 at the first position P1 and the third rubber strip GS3 at the second position P2 can be wound simultaneously. Furthermore, the second rubber strip GS2 at the first position P1 and the fourth rubber strip GS4 at the second position P2 can be wound simultaneously. This improves the production efficiency of the tread compound 10.

[0138] The tread rubber forming apparatus 100B is suitable for performing tread rubber forming methods S1 to S3.

[0139] When the tread compound forming apparatus 100B is used in the execution of the tread compound forming method S1, after the second step S12, the cylinders 101 and 102 are rotated to replace the cylinders 101 and 102 positioned at positions P1 and P2. Furthermore, after the fourth step S14, the cylinders 101 and 102 are rotated to replace the cylinders 101 and 102 positioned at positions P1 and P2. Moreover, after step S14B, the cylinders 101 and 102 are rotated to replace the cylinders 101 and 102 positioned at positions P1 and P2.

[0140] When the tread rubber forming apparatus 100B is used in the execution of the tread rubber forming method S2, the cylinders 101 and 102 are rotated after the second step S22 to replace the cylinders 101 and 102 arranged at positions P1 and P2.

[0141] When the tread rubber forming apparatus 100B is used in the execution of the tread rubber forming method S3, the cylinders 101 and 102 are rotated after the second step S32 to replace the cylinders 101 and 102 arranged at positions P1 and P2.

[0142] In tread compound forming methods S2 and S3 using the tread compound forming apparatus 100B, compared to tread compound forming method S1 using the tread compound forming apparatus 100B, the number of replacements of the cylindrical bodies 101 and 102 located at positions P1 and P2 is reduced. Therefore, in tread compound forming method S2, the tread compound 10, which includes a conductive layer 4 and a three-layer rubber layer consisting of a base layer 1, an intermediate layer 2, and a cover layer 3, is formed more efficiently in a seamless manner.

[0143] Figure 18 The diagram shows a modified example of a tread compound forming apparatus 100C. For the following undescribed parts of the tread compound forming apparatus 100C, the structure of the tread compound forming apparatus 100A described above can be used.

[0144] The tread compound forming apparatus 100C includes: a pair of cylindrical bodies 101 and 102, which serve as the substrate for forming the tread compound 10; and a first applicator 111A, a second applicator 112A, a third applicator 113A, a fourth applicator 114A, and a fifth applicator 115A, which are used to supply rubber strips GS1A, GS2A, GS3A, GS4A, and GS5A.

[0145] The fifth applicator 115A supplies the fifth rubber strip GS5A, which constitutes the conductive layer 4. The fifth rubber strip GS5A is configured with the same conductivity as the third rubber strip GS3A. The fifth rubber strip GS5A may also be configured with a different fit than the third rubber strip GS3A.

[0146] The first applicator 111A, the second applicator 112A, and the third applicator 113A are positioned at the location corresponding to the first position P1. The fourth applicator 114A and the fifth applicator 115A are positioned at the location corresponding to the second position P2.

[0147] With the above-described configuration of the first applicator 111A to the fifth applicator 115A, the rubber strip can be wound simultaneously at the first position P1 and the second position P2. For example, the winding of the first rubber strip GS1A at the first position P1 and the winding of the fourth rubber strip GS4A at the second position P2 can be performed simultaneously. Furthermore, the winding of the second rubber strip GS2A at the first position P1 and the winding of the fourth rubber strip GS4A at the second position P2 can be performed simultaneously. This improves the production efficiency of the tread compound 10.

[0148] The tread rubber forming apparatus 100C is suitable for performing tread rubber forming methods S4 to S6.

[0149] When the tread rubber forming apparatus 100C is used in the execution of the tread rubber forming method S4, the cylinders 101 and 102 are rotated after the fourth step S44 to replace the cylinders 101 and 102 arranged at positions P1 and P2.

[0150] In the tread compound forming method S4 using the tread compound forming apparatus 100C, compared to the tread compound forming method S1 using the tread compound forming apparatus 100B, the number of replacements of the cylinders 101 and 102 located at positions P1 and P2 is reduced. Therefore, in the tread compound forming method S2, the tread compound 10, which includes a conductive layer 4 and a three-layer rubber layer consisting of a base layer 1, an intermediate layer 2, and a cover layer 3, is formed more efficiently in a seamless manner.

[0151] In addition, Figure 17 , 18 In the preferred embodiment, a tread rubber forming apparatus 100B and 100C having a pair of cylindrical bodies 101 and 102 is shown. However, the tread rubber forming apparatus of the present invention may also be configured to include three or more cylindrical bodies (e.g., more than the same number of cylindrical bodies as the applicator).

[0152] Furthermore, in the tread compound forming apparatuses 100B and 100C, the movement of the cylindrical bodies 101 and 102 is not limited to rotation. For example, it can also be a sliding motion along the axial direction or radially perpendicular to the axial direction of the cylindrical bodies 101 and 102. In this case, the rotational motion of the cylindrical bodies 101 and 102 is replaced by a sliding motion.

[0153] The tread rubber forming methods S1 to S6 and the tread rubber forming apparatus 100 to 100C of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments described above and can be implemented in various ways.

Claims

1. A method for forming a tread compound, wherein the method forms an annular tread compound by spirally layering and winding unvulcanized rubber strips around the radially outer side of a cylindrical body. The method for forming the tread rubber includes: The first step involves moving a conductive first rubber strip along the axial direction of the cylindrical body while simultaneously stacking and winding the first rubber strip to form a base layer. In the second step, while moving the non-conductive second rubber strip along the axial direction, the non-conductive second rubber strip is stacked and wound around the outer peripheral surface of the base layer in a region on one side of the axial direction, thereby forming a first intermediate layer. In this second step, the second rubber strip is wound with a winding spacing larger than the width of the second rubber strip, thereby forming a separation part that separates adjacent second rubber strips in the axial direction. The third step involves moving the non-conductive third rubber strip along the axial direction while simultaneously layering and winding the non-conductive third rubber strip around the outer periphery of the first intermediate layer, thereby forming the first covering layer. In the fourth step, a conductive fourth rubber strip is wound around the outer periphery of the first cover layer from the position where it contacts the base layer in the region on the other side of the axial direction relative to the first intermediate layer and the first cover layer, thereby forming a conductive layer. In this fourth step, the fourth rubber strip is wound in the region containing the separation portion. as well as In the fifth step, while moving the third rubber strip relative to the conductive layer in the region on the opposite side of the axial direction along the axial direction, the third rubber strip is layered and wound around the radially outer side of the base layer in such a way that a portion of the conductive layer is exposed on the radially outer side of the first cover layer, thereby forming the second cover layer. In this fifth step, the third rubber strip is wound within the region containing the separation portion. The conductive layer is formed only in the fourth step, and the conductive layer is a single conductive layer wound in one axial direction. The second, third, and fourth rubber strips are wound in the same direction. By sequentially executing the first step, the second step, the third step, the fourth step, and the fifth step, a tread compound comprising a conductive layer and a three-layer rubber layer consisting of a base layer, an intermediate layer, and a cover layer is formed in a seamless manner.

2. A method for forming a tread compound, wherein the method forms an annular tread compound by spirally layering and winding unvulcanized rubber strips around the radially outer side of a cylindrical body. The method for forming the tread rubber includes: The first step involves moving a conductive first rubber strip along the axial direction of the cylindrical body while simultaneously stacking and winding the first rubber strip to form a base layer. In the second step, while moving the non-conductive second rubber strip along the axial direction, the non-conductive second rubber strip is stacked and wound around the outer peripheral surface of the base layer in the region on one side of the axial direction, thereby forming a first intermediate layer. In this second step, the second rubber strip is stacked and wound in such a way that the end edge of the first intermediate layer on the other side of the axial direction is located on the other side relative to the equator of the tread rubber. The third step involves moving the non-conductive third rubber strip along the axial direction while simultaneously layering and winding the non-conductive third rubber strip around the outer periphery of the first intermediate layer, thereby forming the first covering layer. In the fourth step, relative to the region on the opposite side of the first intermediate layer and the first cover layer in the axial direction, a conductive fourth rubber strip is wound around the outer periphery of the first cover layer, starting from the position where it contacts the base layer, thereby forming a conductive layer; and In the fifth step, while moving the third rubber strip along the axial direction relative to the conductive layer in the region on the opposite side of the axial direction, the third rubber strip is layered and wound around the radially outer side of the base layer in such a way that a portion of the conductive layer is exposed on the radially outer side of the first cover layer, thereby forming the second cover layer. The conductive layer is formed only in the fourth step, and the conductive layer is a single conductive layer wound in one axial direction. The second, third, and fourth rubber strips are wound in the same direction. By sequentially executing the first, second, third, fourth, and fifth processes, a tread compound is formed in a seamless manner, comprising a conductive layer and a three-layer rubber layer consisting of a base layer, an intermediate layer, and a cover layer. The axial length W2 of the first intermediate layer formed in the second process is 60% to 80% of the axial length W1 of the tread rubber.

3. A tread compound forming apparatus, comprising, according to claim 1 or 2, forming annular tread compound by spirally winding unvulcanized rubber strips. The tread compound forming apparatus includes: A first applicator moves a first rubber strip along the axial direction of the tread rubber while simultaneously layering and winding the first rubber strip to form a base layer. The second applicator moves a non-conductive second rubber strip along the axial direction while simultaneously layering and wrapping the non-conductive second rubber strip around one side of the axial direction on the outer peripheral surface of the base layer, thereby forming a first intermediate layer. A third applicator moves a non-conductive third rubber strip along the axial direction while simultaneously wrapping the non-conductive third rubber strip around the outer periphery of the first intermediate layer, thereby forming a first cover layer; and A fourth applicator, located on the opposite side of the first intermediate layer and the first cover layer in the axial direction, winds a conductive fourth rubber strip across the outer periphery of the first cover layer, starting from the point of contact with the base layer, thereby forming a conductive layer. The conductive layer is formed only in one process based on the fourth applicator, and the conductive layer is a single conductive layer wound in one axial direction. The second, third, and fourth rubber strips are wound in the same direction. By sequentially performing the processes based on the first applicator, the second applicator, the third applicator, and the fourth applicator, a tread compound comprising a conductive layer and a three-layer rubber layer consisting of a base layer, an intermediate layer, and a cover layer is formed in a seamless manner.

4. The tread rubber forming apparatus according to claim 3, wherein, The third applicator moves the third rubber strip along the axial direction relative to the conductive layer in a region on the opposite side of the axial direction, while simultaneously layering and wrapping the third rubber strip around the base layer and the radially outer side of the conductive layer in such a way that a portion of the conductive layer is exposed on the radially outer side of the first cover layer, thereby forming a second cover layer.

5. The tread compound forming apparatus according to claim 3 or 4, comprising: A pair of cylindrical bodies, exclusively positioned in a first or second position, with the rubber strip wound around them; and A movable part that moves the cylindrical bodies in order to exchange the cylindrical bodies arranged at various positions. The first applicator and the second applicator are positioned at a location corresponding to the first position. The third and fourth applicators are positioned at locations corresponding to the second position.

6. A tread compound forming apparatus, wherein the tread compound forming apparatus forms annular tread compound by spirally winding unvulcanized rubber strips. The tread compound forming apparatus includes: A first applicator moves a conductive first rubber strip along the axial direction of the tread rubber while simultaneously layering and winding the first rubber strip to form a base layer. The second applicator moves the non-conductive second rubber strip along the axial direction while simultaneously wrapping the non-conductive second rubber strip around the outer periphery of the base layer, thereby forming an intermediate layer. A third applicator, starting from the position where it contacts the base layer, wraps a conductive third rubber strip around the outer periphery of the intermediate layer, thereby forming a first conductive layer; A fourth applicator, which moves a non-conductive fourth rubber strip along the axial direction while simultaneously wrapping the non-conductive fourth rubber strip around the outer peripheral surface of the intermediate layer, thereby forming a cover layer; and A fifth applicator, starting from the position where it contacts the first conductive layer, winds a conductive fifth rubber strip across the outer periphery of the cover layer, thereby forming a second conductive layer. The first conductive layer and the second conductive layer have the same axial winding direction. The second, third, and fourth rubber strips are wound in the same direction. The winding of the first rubber strip based on the first applicator and the winding of the fourth rubber strip based on the fourth applicator, as well as the winding of the second rubber strip based on the second applicator and the winding of the fourth rubber strip based on the fourth applicator, can be performed simultaneously.

7. The tread rubber forming apparatus according to claim 6, wherein, The second applicator layers and winds the second rubber strip around the outer peripheral surface of the base layer in one side of the axial direction, thereby forming a first intermediate layer. The third applicator wraps around the third rubber strip across the outer peripheral surface of the first intermediate layer in a region on the opposite side of the first intermediate layer in the axial direction, thereby forming the first conductive layer. The second applicator layers and wraps the second rubber strip around the base layer and the outer peripheral surface of the first conductive layer in such a way that a portion of the first conductive layer is exposed radially outward of the second rubber strip, thereby forming a second intermediate layer.

8. The tread rubber forming apparatus according to claim 7, wherein, The fourth applicator layers and wraps the fourth rubber strip around a portion of the outer peripheral surface of the first intermediate layer, thereby forming a first covering layer. The fifth applicator wraps around the fifth rubber strip across the outer peripheral surface of the first cover layer in a region on the opposite side of the first cover layer in the axial direction, thereby forming the second conductive layer. The fourth applicator layers and wraps the fourth rubber strip around the second intermediate layer and the outer peripheral surface of the second conductive layer in such a way that a portion of the second conductive layer is exposed radially outward from the fourth rubber strip, thereby forming a second cover layer.

9. The tread compound forming apparatus according to any one of claims 6 to 8, comprising: A pair of cylindrical bodies, exclusively positioned in a first or second position, with the rubber strip wound around them; and A movable part that moves the cylindrical bodies in order to exchange the cylindrical bodies arranged at various positions. The first to the third applicator are positioned at locations corresponding to the first position. The fourth and fifth applicators are positioned at locations corresponding to the second position.

Images