JP6693265B2 - Rigid core for tire formation - Google Patents

Description

  The present invention relates to a rigid core for forming a green tire.

  In recent years, for example, a method for manufacturing a tire in which an unvulcanized raw tire is formed on the outer surface of a rigid core and the raw tire is vulcanized and molded together with the rigid core is proposed in Patent Document 1 below. The rigid core has an annular core body having a center hole extending in the core axis direction, and an inner cylinder portion arranged in the center hole. The core body is composed of a plurality of segments arranged in the core circumferential direction. Each segment is fixed to the inner tubular portion by a fastener such as a bolt.

JP2012-158064A

  The rigid core of Patent Document 1 requires fastening and removing work of the fixing tool at the time of assembling and disassembling the core body. Therefore, the rigid core of Patent Document 1 has a problem that the productivity of the tire is reduced.

  The present invention has been devised in view of the above circumstances, and a main object of the present invention is to provide a rigid core for forming a tire that can improve the productivity of the tire.

  The present invention is a rigid core provided with a molding surface for forming a green tire on the outer surface, and an annular core body having a central hole extending in the axial direction of the core, and And the inner cylinder body, the core body is composed of a plurality of segments arranged in the core circumferential direction, each segment, an arm portion protruding toward the inner cylinder portion side, A hook portion having a claw portion that extends from the arm portion to one side in the core axis direction is provided, and the inner cylinder portion is inserted into the hook portion of each segment to thereby A holding hole for restraining and holding the movement to one side and the movement in the core radial direction is formed.

  In the rigid core for tire formation according to the present invention, it is preferable that the hook portion is detachably attached to a surface of the segment on the side of the central hole.

  In the rigid core for tire formation according to the present invention, the segment has a first segment having a small circumferential length on the central hole side and a circumferential length on the central hole side that is smaller than the first segment. At least one second segment which is large, and in the at least one second segment, the maximum length of the hook portion of the hook portion in the circumferential direction of the core is the nail of the hook portion of the first segment. It is desirable that the length is larger than the maximum length in the circumferential direction of the core.

  In the rigid core for forming a tire according to the present invention, at least one of the hook portions has a plurality of the claw portions arranged in the arm portion at a distance in a core circumferential direction, and the holding hole. Preferably has a plurality of hole portions into which the respective claw portions are independently inserted.

  In the rigid core for tire formation according to the present invention, it is preferable that the holding hole is provided on an end surface on the other side in the core axis direction of the inner tubular portion.

  The rigid core for tire formation of the present invention has an annular core body having a center hole extending in the core axis direction, and an inner cylinder portion arranged in the center hole. The core body is composed of a plurality of segments arranged in the core circumferential direction. Each segment is provided with a hook portion having an arm portion protruding toward the inner cylinder portion side and a claw portion extending from the arm portion to one side in the core axis direction. The inner cylindrical portion is formed with a holding hole for restraining and holding the movement of each segment to one side and the movement in the core radial direction by inserting the hook portion of each segment.

  Due to the hook portion and the holding hole, each segment is held in the inner tubular portion without using a fastener such as a bolt. Also, since each segment is allowed to move from the held state to the other side in the core axis direction, by moving the cylindrical section to one side in the core axis direction, the inner cylinder section and each segment are moved. Can be easily removed. Therefore, the rigid core for tire formation of the present invention can improve tire productivity.

It is sectional drawing which shows an example of the rigid core for tire formation of this invention. It is a top view of a core main part and an inner cylinder part. It is an exploded perspective view of a rigid core. It is a partial perspective view of a segment and an inner cylinder part. It is sectional drawing which shows an example of a hook part and a holding hole. It is an exploded perspective view of a hook part. (A)-(C) is sectional drawing explaining disassembly of a rigid core. It is sectional drawing explaining the taking out of the core main body. It is sectional drawing explaining the assembly of a rigid core. It is sectional drawing explaining the attachment to the inner cylinder part of a 2nd side wall body. It is a top view which shows a part of 1st segment and 2nd segment of other embodiment of this invention. It is a partial perspective view which shows the hook part of other embodiment of this invention.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of a rigid core for tire formation (hereinafter, may be simply referred to as “rigid core”) of the present invention. FIG. 2 is a plan view of the core body and the inner cylindrical portion. FIG. 3 is an exploded perspective view of the rigid core. As shown in FIG. 1, the rigid core 1 according to the present embodiment has a molding surface 2 for molding the green tire Ta on the outer surface 1S.

  The outer surface 1S of the rigid core 1 substantially matches the inner surface shape of the finished tire (vulcanized tire) T. A green tire Ta is formed by sequentially attaching tire constituent members such as an inner liner, a carcass ply, a belt ply, a sidewall rubber, and a tread rubber on the outer surface 1S. The raw tire Ta is put into a vulcanization mold (not shown) together with the rigid core 1 to vulcanize and form the raw tire Ta. The rigid core shown in FIG. 1 is supported by the holding shaft 3.

  The rigid core 1 has a core body 5 and an inner cylinder portion 6. Further, the rigid core 1 of the present embodiment has a first side wall body 7 and a second side wall body 8 arranged on both sides of the core body 5 in the core axis direction.

  The core body 5 is formed in an annular shape having a center hole 5h extending in the core axis direction. Further, the core body 5 is formed with a bulging portion 15 which bulges outward in the core axial direction. The bulging portion 15 has a tapered surface 16 that is continuous with the outer surface 1S and that is inclined inward in the core radial direction and outward in the core axial direction.

  Inside the core body 5, a concave portion 14 that is concentric with the core body 5 is formed. In the present embodiment, steam, which is a heat medium for vulcanization heating, is supplied into the recess 14 through a flow path (not shown) provided in the inner tubular portion 6. The recess 14 may house a heat source for vulcanization heating such as an electric heater.

  As shown in FIGS. 2 and 3, the core body 5 is composed of a plurality of segments 10 arranged in the core circumferential direction and can be disassembled. Further, the core body 5 is formed in an annular shape by assembling the segments 10.

  The segment 10 of this embodiment includes a first segment 10A and a second segment 10B. In this embodiment, the first segments 10A and the second segments 10B are alternately arranged in the core circumferential direction.

  As shown in FIG. 2, in the first segment 10A of the present embodiment, the split surfaces 10s and 10s at both ends in the tire circumferential direction are oriented in a direction in which the length in the tire circumferential direction decreases toward the inner side in the core radial direction. It is inclined. As a result, the first segment 10A is formed with a small circumferential length L1 on the center hole side. On the other hand, in the second segment 10B, the split surfaces 10s and 10s at both ends in the tire circumferential direction are inclined toward the inner side in the core radial direction in a direction in which the length in the tire circumferential direction increases. As a result, the circumferential length L2 of the second segment 10B on the side of the central hole 5h is formed larger than the circumferential length L1 of the first segment 10A on the side of the central hole 5h.

  In such a core body 5, in the state where the finished tire T is arranged on the outer surface 1S, the second segment 10B is moved to the inner side in the radial direction of the core and removed, and then the first segment 10A is moved to the core radius. The core body 5 is removed from the inner cavity of the finished tire T by moving the core body 5 inward in the direction and removing it.

  FIG. 4 is a partial perspective view of the segment 10 and the inner tubular portion 6. As shown in FIGS. 2 and 4, on the surface 10i on the side of the central hole of each segment 10, there is provided a ridge portion 17 that projects inward in the core radial direction. The protruding portion 17 of the present embodiment extends continuously in the core axis direction. As shown in FIG. 4, the ridge portion 17 connects the pair of outer side surfaces 17s and 17s extending inward from the center hole side surface 10i to the inner side of the core and the inner end of the pair of outer side surfaces 17s and 17s. The end face 17i is included, and the cross section is formed into a substantially rectangular shape. The ridge portion 17 is fitted into the groove portion 18 provided on the outer peripheral surface 6o of the inner cylindrical portion 6.

  As shown in FIGS. 2 and 3, each segment 10 is provided with a hook portion 21. The hook portion 21 is inserted into the holding hole 22 of the inner tubular portion 6. As shown in FIG. 4, the hook portion 21 of the present embodiment includes an arm portion 23 projecting to the inner cylinder portion 6 side (that is, the inner side in the radial direction of the core), and one side in the core axial direction from the arm portion 23. It includes a claw portion 24 extending to S1 and is formed in an L shape in a side view. The hook portion 21 is provided on the surface 10i of the segment 10 on the side of the central hole, and in the present embodiment, on the inner end surface 17i of the protruding portion 17. The hook portion 21 is fixed to the other side S2 in the core axis direction of the segment 10.

  FIG. 5 is a cross-sectional view showing an example of the hook portion and the holding hole. FIG. 6 is an exploded perspective view of the hook portion. As shown in FIGS. 5 and 6, the arm portion 23 projects from the surface 10i of the segment 10 on the side of the center hole toward the inner cylinder portion 6 side (that is, the inner side in the core radial direction). The arm portion 23 of the present embodiment is formed in a horizontally long rectangular shape having a large length in the segment circumferential direction.

  As shown in FIG. 6, the arm portion 23 is provided with at least one (two in the present embodiment) through holes 25, 25 penetrating in the core radial direction. In such a through hole 25, a fastener 26 such as a bolt is inserted from the side of the central hole 5h toward the side of the segment 10 (that is, the outer side in the radial direction of the core), so that the hook portion 21 is detached from the segment 10. Can be freely attached. Thereby, the maintainability of the hook portion 21 and the segment 10 can be improved.

  As shown in FIGS. 5 and 6, the claw portion 24 is a surface of the arm portion 23 on one side S1 of the arm circumferential direction on the inner cylinder portion 6 side of the arm portion 23 (that is, inside of the core radial direction). It extends from 23i to one side S1 in the core axis direction. Therefore, the claw portion 24 and the segment 10 are separated from each other in the core radial direction. As shown in FIG. 6, the claw portion 24 of the present embodiment is formed in a horizontally long rectangular cross section. The maximum length L3 in the core circumferential direction of the claw portion 24 of the present embodiment is set to be the same as the maximum length L4 of the arm portion 23.

  As shown in FIGS. 2 and 3, the inner cylinder portion 6 of the present embodiment is formed in a cylindrical shape. The inner cylinder portion 6 is arranged in the center hole 5h of the core body 5. As a result, the inner cylinder portion 6 can prevent the segments 10 from moving inward in the core radial direction.

  As shown in FIGS. 3 and 4, on the outer peripheral surface 6o of the inner tubular portion 6, a plurality of groove portions 18 for fitting the ridge portions 17 of the respective segments 10 and guiding slidably in the core axial direction are provided. It is provided. The groove portion 18 of the present embodiment is recessed inward in the core radial direction and extends continuously in the core axial direction. As shown in FIG. 4, the groove portion 18 includes a pair of inner side surfaces 18s, 18s extending from the outer peripheral surface 6o to the inner side in the core radial direction, and a bottom surface 18i joining the inner ends of the pair of inner side surfaces 18s, 18s, The cross section is formed into a substantially rectangular shape.

  Such a groove portion 18 can position each segment 10 with respect to the inner cylinder portion 6 in the core circumferential direction by fitting the ridge portion 17 therein. It should be noted that the groove portion 18 and the ridge portion 17 do not restrain the movement of each segment 10 in the radial direction of the core, unlike the dovetail groove and the dovetail not shown. Therefore, the fitting work between the groove portion 18 and the protruding portion 17 does not require high precision, and thus it is possible to prevent the productivity of the tire from decreasing.

  As shown in FIGS. 3 and 4, a holding hole 22 is formed in the inner tubular portion 6. The holding hole 22 is provided on the end surface 6t on the other side S2 in the core axis direction of the inner tubular portion 6. The holding holes 22 are spaced in the core circumferential direction in accordance with the positions of the claw portions 24 (shown in FIG. 4) of the hook portions 21 provided in each segment 10. Further, the holding hole 22 of the present embodiment is provided on the inner side in the core radial direction of the groove portion 18.

  As shown in FIGS. 4 and 5, the holding hole 22 of the present embodiment includes a cutout portion 31 and a hole portion 32. The cutout portion 31 is formed by cutting out the end surface 6t side on the other side S2 in the core axis direction of the inner cylinder portion 6 to the outer peripheral surface 6o side of the inner cylinder portion 6 (outer side in the core radial direction). The hole portion 32 extends from the cutout portion 31 to the one side S1 in the core axis direction. Due to the cutout portion 31 and the hole portion 32, the holding hole 22 is formed in an L shape in a cross section in the core axis direction.

  The size of the cutout portion 31 (that is, the length in the core circumferential direction, the width in the core radial direction, and the depth in the core axial direction) is the same as or slightly larger than the size of the arm portion 23 of the hook portion 21. It is formed. Further, the size of the hole portion 32 is formed to be the same as or slightly larger than the size of the claw portion 24 of the hook portion 21. Such a holding hole 22 can be inserted with the hook portion 21 on the other side S2 in the core axis direction.

  By inserting the hook portion 21, the notch portion 31 can restrain and hold the movement of the arm portion 23 of the hook portion 21 in the one side S1 of the core axis direction and the core circumferential direction. Further, the hole portion 32 can restrain and hold the movement of the claw portion 24 in the core radial direction and the core circumferential direction by inserting the claw portion 24 of the hook portion 21. Therefore, the holding hole 22 restrains and holds the movement of the segment 10 toward the one side S1 of the core axis direction, the core radial direction, and the core circumferential direction by inserting the hook portion 21. be able to. The holding hole 22 does not restrain the movement of the hook portion 21 on the other side S2 in the core axis direction. Therefore, each segment 10 is allowed to move from the state where the hook portion 21 is held in the holding hole 22 to the other side S2 in the core axis direction.

  As shown in FIGS. 1 and 3, the first side wall body 7 is arranged on one side S1 of the inner cylinder portion 6 in the core axis direction. The first side wall body 7 has a disk-shaped first side plate portion 33. The first side plate portion 33 includes a first flange portion 34 that comes into contact with the tapered surface 16 of the core body 5. Such a first flange portion 34 aligns the first side wall body 7 and the core body 5 concentrically by contacting the tapered surface 16 of the core body 5 on the one side S1 in the core axis direction. sell. Further, the first flange portion 34 can hold the bulging portion 15 of the core body 5 (each segment 10) in the radial direction of the core with the inner tubular portion 6.

  Although the 1st side wall body 7 of this embodiment is being fixed to the inner cylinder part 6 using the bolt 35 (shown in FIG. 1), it can also be fixed by welding etc., for example. Such a first side wall body 7 can prevent the movement of each segment 10 to the one side S1 in the core axis direction.

  The second side wall body 8 is arranged on the other side S2 in the core axis direction of the inner cylinder portion 6. The second side wall body 8 has a disk-shaped second side plate portion 36. The second side plate portion 36 includes a second flange portion 37 that contacts the tapered surface 16 of the core body 5. Such a second flange portion 37 abuts on the tapered surface 16 of the core body 5 on the one side S1 of the core axial direction to align the second side wall body 8 and the core body 5 concentrically. You can. Further, the second flange portion 37 can sandwich and hold the bulging portion 15 of the core body 5 (each segment 10) between the inner cylindrical portion 6 and the inner cylindrical portion 6 in the core radial direction.

  In the second side wall body 8 of the present embodiment, a boss portion 39 that can be screwed into the inner threaded portion 38 of the inner tubular portion 6 is concentrically provided. Therefore, the second side wall body 8 can be detachably attached to the inner cylinder portion 6 by the boss portion 39 and the inner screw portion 38. Such a second side wall body 8 can prevent the movement of each segment 10 to the other side S2 in the axial direction.

  The first side plate portion 33 of the first side wall body 7 and the second side plate portion 36 of the second side wall body 8 are provided with support shaft portions 41 that project outward in the core axial direction. The support shaft 41 is, for example, attached to a transfer device (not shown) or a vulcanization mold (not shown). The support shaft portion 41 of the present embodiment is detachably connected to a carrying device or the like via a connecting means 42 having a ball lock mechanism, for example.

  Next, an extracting process for taking out the rigid core 1 from the finished tire T and an assembling process for assembling the rigid core 1 will be described. 7A to 7C are cross-sectional views for explaining the disassembly of the rigid core 1.

  As shown in FIG. 7A, in the take-out step, first, the rotary shaft 43 rotatable by the driving means is connected to the support shaft portion 41 provided on the second side wall body 8 of the rigid core 1. Connect via means 42. Then, by rotating the rotary shaft 43, the second side wall body 8 can be removed from the rigid core 1 as shown in FIG. 7 (B). The removed second side wall body 8 is transferred to the assembly place K (shown in FIG. 9) together with the rotating shaft 43.

  Next, in the take-out step, the core body receiver 44 is raised from the one side S1 of the rigid core 1 in the core axis direction, and the core body 5 is supported by the one side S1. Then, as shown in FIG. 7C, the holding shaft 3 is moved to the one side S1 in the core axis direction together with the first side wall body 7 and the inner tubular portion 6. As described above, each segment 10 is allowed to move from the state where the hook portion 21 is held in the holding hole 22 to the other side S2 in the core axis direction. Therefore, the inner cylinder portion 6 that restrains each segment 10 can be easily moved to the one side S1 in the core axis direction. Thereby, in the take-out step, the first side wall body 7 and the inner cylinder portion 6 can be integrally removed from the rigid core 1. The removed first side wall body 7 and inner cylinder portion 6 are transferred to the assembly place K (shown in FIG. 9) together with the holding shaft 4.

  In the present embodiment, the length L3t (shown in FIG. 6) in the core axis direction of the claw portion 24 of the hook portion 21 extends the total length L5 (shown in FIG. 3) in the core axis direction of the inner tubular portion 6. It is formed smaller than the conventional dovetail groove and dovetail. As a result, the rigid core 1 of this embodiment can release the insertion of the hook portion 21 by a relatively small movement in the axial direction of the core. Therefore, in the rigid core 1 of the present embodiment, the inner cylinder portion 6 can be easily removed from the core body 5 as compared with the conventional rigid core in which the dovetail groove and the dovetail tenon are provided. In order to effectively exhibit such an action, the length L3t of the claw portion 24 in the core axis direction is set to 10% to 50% of the total length L5 of the inner tubular portion 6 in the core axis direction. Is desirable.

  As shown in FIG. 2 and FIG. 4, in the present embodiment, since the protrusion 17 and the groove 18 are fitted so as to be slidable in the core axial direction, the core is prevented from being displaced in the circumferential direction. The inner cylinder portion 6 can be guided to the one side S1 in the core axis direction. Thereby, the insertion between the hook portion 21 and the holding hole 22 can be smoothly released.

  FIG. 8 is a cross-sectional view illustrating the removal of the core body 5. As shown in FIG. 8, in the take-out step, the segments 10 are taken out one by one from the core body 5 held on the core body receiver 44. In the present embodiment, the first segment 10A is removed after being removed from the second segment 10B. As a result, the rigid core 1 can be taken out from the finished tire T. For taking out the segment 10, it is desirable to use a holding jig 46 attached to the robot arm, for example. The taken out segment 10 is transferred to the assembly place K (shown in FIG. 9) together with the holding jig 46.

  FIG. 9 is a cross-sectional view illustrating the assembly of the rigid core 1. In the assembly process, each segment 10 is sequentially mounted around the inner cylindrical portion 6 at the assembly location K. In the present embodiment, first, the segment 10 is positioned on the other side S2 in the core axis direction of the inner tubular portion 6. Next, the segment 10 is moved from the other side S2 in the core axis direction to the one side S1, and the hook portion 21 of the segment 10 is inserted into the holding hole 22 of the inner cylinder portion 6. As a result, the movement of the segment 10 toward the one side S1 in the core axis direction and the movement in the core radial direction are restrained, so that the segment 10 is stably held by the inner tubular portion 6.

  As shown by the chain double-dashed line in FIG. 9, the bulging portion 15 of the segment 10 is provided between the first flange portion 34 of the first side wall body 7 and the inner tubular portion 6 on the one side S1 in the core axis direction. Are sandwiched and held. As a result, the movement of each segment 10 in the core radial direction is restricted on both the one side S1 and the other side S2 of the core axial direction. As a result, each segment 10 can be prevented from falling off from the inner tubular portion 6 due to, for example, vibration when attached to the inner tubular portion 6.

  In the present embodiment, the ridge portion 17 (shown in FIGS. 3 and 4) of the segment 10 is fitted into the groove portion 18 (shown in FIGS. 3 and 4) of the inner tubular portion 6 while the segment 10 is placed on one side. Sliding to S1. As a result, the segment 10 can prevent the positional displacement of the segment 10 in the circumferential direction of the core with respect to the inner tubular portion 6, so that the hook portion 21 can be stably inserted into the holding hole 22.

  FIG. 10 is a cross-sectional view illustrating the attachment of the second side wall body 8 to the inner cylinder portion 6. In the assembly process, after the first segment 10A and the second segment 10B are all mounted around the inner cylindrical portion 6, the second side wall body 8 is mounted on the inner cylindrical portion 6. At this time, by rotating the second side wall body 8, the boss portion 39 of the second side wall body 8 is screwed into the inner threaded portion 38 of the inner cylindrical portion 6. As a result, the rigid core 1 is assembled.

  As described above, in the rigid core 1 of the present embodiment, a fixing tool (not shown) such as a bolt is not used to fix each segment 10 and the inner tubular portion 6, so that the core body 5 is assembled and The disassembly (shown in FIGS. 7, 8 and 9) can be performed in a short time. Therefore, the rigid core 1 of the present embodiment can improve the productivity of tires. Moreover, the rigid core 1 of the present embodiment can be accurately assembled because the segments 10 are positioned by inserting the hook portions 21 of the segments 10.

  As shown in FIG. 1, in each segment 10, the hook portion 21 is inserted into the holding hole 22, the inner cylindrical portion 6 is arranged in the central hole 5h, and the first side wall body 7 and the second side wall body 8 are arranged. The holding of the core prevents movement in the core axial direction, the core radial direction, and the core circumferential direction, so that the shape of the outer surface 1S of the rigid core 1 can be maintained with high accuracy. Since the rigid core 1 does not require fastening and removing work of fasteners such as bolts at the time of assembling and disassembling the core body 5, tire productivity can be greatly improved. Therefore, the rigid core 1 of the present embodiment can easily achieve automation of assembly and disassembly.

  As shown in FIG. 6, in the claw portion 24 of the hook portion 21, a chamfered portion 27 is formed at an inner corner between both side surfaces 24s, 24s in the core circumferential direction and an outer end surface 24o joining the both side surfaces 24s, 24s. It is desirable to be done. The chamfered portion 27 of the present embodiment is formed in an arc shape. Due to the chamfered portion 27, the outer end surface 24o on one side of the claw portion 24 in the core axis direction is set to have a small length L3s in the core circumferential direction. (Shown in FIG. 3) can be smoothly inserted. The chamfered portion 27 may also be provided at the corners between the side surfaces 24t, 24t in the radial direction of the core and the outer end surface 24o.

  As shown in FIG. 5, in the claw portion 24 of the holding hole 22, it is desirable that the width W3 in the core radial direction gradually decreases from the other side S2 in the core axial direction toward the one side S1. Thereby, the claw portion 24 can be smoothly inserted into the hole portion 32 of the holding hole 22. Further, the width W3a of the other side S2 in the core axis direction of the claw portion 24 is made slightly larger than the width W5 of the other side S2 in the core axis direction of the hole portion 32 so that the claw portion 24 can be tightly fitted. You can Thereby, the claw portion 24 can be firmly held by the hole portion 32. In addition, in the claw portion 24 of the present embodiment, the width W3 in the core radial direction gradually decreases from the other side S2 to the one side S1 in the core axis direction, but is not limited to such an aspect. is not. For example, the width W3 of the claw portion 24 may be set to be the same from the other side S2 to the one side S1 in the core axis direction.

  As shown in FIG. 2 and FIG. 4, the cutout portion 31 of the holding hole 22 of the present embodiment has a pair of enlarged portions 47, which are notched by being enlarged on both sides in the core circumferential direction on the inner side in the radial direction of the core. Includes 47. The enlarged portion 47 of the present embodiment is formed in an arc shape in a side view of the other side S2 in the core axis direction. The core circumferential direction length of the cutout portion 31 including the enlarged portions 47, 47 is formed to be larger than the core circumferential direction length of the claw portion 24 of the hook portion 21. Accordingly, when the hook portion 21 is inserted, the claw portion 24 can be prevented from colliding with the end surface 6t on the other side S2 in the core axis direction of the inner tubular portion 6.

  The hook portion 21 is preferably made of the same material as the inner cylinder portion 6. As a result, the hook portion 21 and the inner cylinder portion 6 have the same coefficient of thermal expansion, so that interference between the claw portion 24 and the holding hole 22 due to the difference in thermal expansion can be prevented during vulcanization.

  Although the hook portion 21 and the holding hole 22 having the same shape are used for each segment 10 of the present embodiment, the present invention is not limited to such an aspect. For example, the hook portion 21 and the holding hole 22 attached to the first segment 10A may be different from the hook portion 21 and the holding hole 22 attached to the second segment 10B. FIG. 11: is a top view which shows some 1st segment 10A and 2nd segment 10B of other embodiment of this invention.

  In this embodiment, in at least one second segment 10B, the maximum length L3b of the claw portion 24 of the hook portion 21 is formed larger than the maximum length L3a of the claw portion 24 of the hook portion 21 of the first segment 10A. Has been done. In this case, the hole portion 32 of the holding hole 22 into which each claw portion 24 is inserted is also formed to be the same size as or slightly larger than the size of each claw portion 24.

  As shown in FIG. 2, the circumferential length L2 of the second segment 10B on the side of the central hole 5h is formed larger than the circumferential length L1 of the first segment 10A on the side of the central hole 5h. As shown in FIG. 11, since the claw portion 24 of the hook portion 21 of the second segment 10B is formed to be relatively larger than the claw portion 24 of the hook portion 21 of the first segment 10A, it is relatively large. The second segment 10B having a large circumferential length L2 can be stably supported. In order to effectively exhibit such an action, the maximum length L3b of the claw portion 24 of the second segment 10B is 1.1 to 2.0 times the maximum length L3a of the claw portion 24 of the first segment 10A. It is desirable to set to. Further, the claw portion 24 having the maximum length L3b is preferably adopted in the hook portions 21 of all the second segments 10B. When the circumferential lengths of the segments 10 are different from each other, the maximum length of the claw portion 24 of the hook portion 21 may be set in accordance with the ratio of the circumferential lengths.

  In each of the hook portions 21 of the above-described embodiments, the arm portion 23 is provided with the one claw portion 24, but the present invention is not limited to such an aspect. For example, at least one of the hook portions 21 may have the arm portion 23 having a plurality of claw portions 24 that are spaced apart from each other in the core circumferential direction. FIG. 12 is a partial perspective view showing a hook portion 21 according to still another embodiment of the present invention. The hook portion 21 of this embodiment has a pair of claw portions 24, 24.

  The arm portion 23 of this embodiment includes a base portion 23a and a pair of protruding portions 23b and 23b. The base portion 23a is fixed to the surface 10i (shown in FIG. 4) on the center hole side of each segment 10. The projecting portion 23b projects from the inner surface 23t in the core radial direction of the base portion 23a toward the inner cylinder portion 6 (that is, the inner side in the core radial direction) at the end portion of the base portion 23a in the core circumferential direction. As a result, the arm portion 23 is formed in a U shape in a plan view as seen from the other side S2 in the core axis direction. The through hole 25 is provided so as to penetrate the protrusion 23b and the base 23a.

  The claw portion 24 of this embodiment extends from the end surface on the one side S1 in the core axis direction of the protrusion 23b to the one side S1 in the core axis direction. In addition, the holding hole 22 of this embodiment has a hole portion 32 (not shown) into which each claw portion 24 is independently inserted. The size of the hole portion 32 is the same as or slightly larger than the size of the claw portion 24.

  In the hook portion 21 of this embodiment, the claw portions 24 are independently held by the hole portions 32 on both sides in the core circumferential direction, so that the segment 10 can be stably held. Since the pair of claw portions 24, 24 are provided so as to be separated from each other in the core circumferential direction, for example, the holding hole 22 is provided while avoiding a structure (for example, a bolt or the like) previously provided in the inner tubular portion 6. be able to. Therefore, it is possible to prevent a design change or the like of the inner cylindrical portion 6. Although the hook portion 21 of this embodiment has a mode in which the pair of claw portions 24, 24 is provided, the hook portion 21 may be provided with three or more claw portions.

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

5 Core body 6 Inner cylinder 21 Hook 22 Holding hole 23 Arm 24 Claw

Claims (4)

A rigid core having a molding surface for forming a raw tire on the outer surface,
An annular core body having a central hole extending in the core axis direction,
An inner cylinder portion arranged in the central hole,
The core body is composed of a plurality of segments arranged in the core circumferential direction,
Each segment is provided with a hook portion having an arm portion projecting toward the inner cylinder portion side and a claw portion extending from the arm portion to one side in the core axis direction,
The inner cylinder portion is formed with a holding hole for restraining and holding the movement of each segment to the one side and the movement in the core radial direction by inserting the hook portion of each segment ,
At least one of the hook portions has a plurality of the claw portions arranged on the arm portion and spaced apart from each other in the core circumferential direction,
A rigid core for tire formation , wherein the holding hole has a plurality of hole portions into which the claw portions are independently inserted . A rigid core having a molding surface for forming a raw tire on the outer surface,
  An annular core body having a central hole extending in the core axis direction,
  An inner cylinder portion arranged in the central hole,
  The core body is composed of a plurality of segments arranged in the core circumferential direction,
  Each segment is provided with a hook portion having an arm portion protruding toward the inner cylinder portion side and a claw portion extending from the arm portion to one side in the core axis direction,
  In the inner cylinder portion, by inserting the hook portion of each segment, a holding hole for restraining and holding the movement of each segment to the one side and the movement in the core radial direction is formed,
  The rigid core for tire formation, wherein the holding hole is provided on an end surface on the other side in the core axis direction of the inner tubular portion. The rigid core for tire formation according to claim 1 or 2 , wherein the hook portion is detachably attached to a surface of the segment on the side of the central hole . The segment is a first segment having a small circumferential length on the side of the central hole,
And at least one second segment whose circumferential length on the side of the central hole is larger than the first segment,
In the at least one of the second segments, the maximum length of the hook portion of the hook portion in the core circumferential direction is larger than the maximum length of the hook portion of the first segment in the core circumferential direction of the hook portion. A rigid core for forming a tire according to claim 1, which is large .

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