mold

Abstract

Provided is a mold capable of suppressing circumferential positional deviation. The mold (2) has: a plurality of segments (8) that form a tread of a tire; a first side plate (10) that forms one of a pair of outer surfaces of a side of the tire; a first engaging member (14) that is fixed to the segment (8); and a second engaging member (16) that is fixed to the first side plate (10), has a hardness (H2) that is smaller than a hardness (H1) of the first engaging member (14), and is capable of engaging with the first engaging member (14).

Description

TECHNICAL FIELD

[0001] The present application relates to a mold for a tire. BACKGROUND

[0002] In a method of manufacturing a tire, a green tire is charged to a mold for a tire, and the green tire is pressurized and heated to obtain a tire from the green tire. As one of such molds, there is a mold having a segment that forms a tread and a pair of side plates that form outer surfaces of a pair of sidewalls, respectively.

[0003] In the mold, the segment and the side plates sometimes have a positional deviation in a circumferential direction. The positional deviation in the circumferential direction causes a positional deviation of the tread of the tire from the outer surfaces of the sidewalls. In particular, in a tire having a pattern of grooves or blocks that span the tread and the outer surfaces of the sidewalls, the appearance is damaged.

[0004] In Patent Literature 1, there is disclosed a mold that engages a locking pin protruding from a segment with a groove of a side plate to position the segment and the side plate in the circumferential direction. In the mold, the positional deviation of the segment and the side plate in the circumferential direction is suppressed.

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2007-269005

[0006] In the mold, when the segment and the side plate have a positional deviation, a large force acts on the locking pin. The large external force sometimes deforms the locking pin to break it. Also, the large external force can deform the segment from which the locking pin protrudes. Such deformation causes the positional deviation of the segment and the side plate in the circumferential direction. SUMMARY

[0007] An object of the present application is to provide a mold that can suppress a positional deviation in a circumferential direction.

[0008] The mold of the present application has a plurality of segments that form a tread of a tire, a first side plate that forms one of a pair of outer surfaces of a pair of sidewalls of the tire, a first locking member that is fixed to an arbitrary segment, and a second locking member that is fixed to the first side plate, has a hardness H2 that is smaller than a hardness H1 of the first locking member, and can be engaged with the first locking member.

[0009] It is preferable that the hardness of the segment to which the first locking member is fixed be smaller than the hardness of the first side plate.

[0010] It is preferable that the first locking member have a recess. The second locking member has a protrusion that is engaged with the recess.

[0011] It is preferable that the plurality of segments be arranged with an axial direction as a vertical direction, and the first side plate be arranged on a lower side of the plurality of segments. The recess is open at a lower surface of the first locking member.

[0012] Preferably, the second engaging member is detachably attached to the first side plate.

[0013] Preferably, the difference H1-H2 between the hardness H1 and the hardness H2 is 350 HBW or more and 450 HBW or less.

[0014] Preferably, the first engaging member is made of alloy tool steel.

[0015] Preferably, the second engaging member is made of chromium-molybdenum steel.

[0016] Preferably, the mold has a second side plate that molds the other of the pair of side surfaces, a third engaging member that is fixed to any of the sector members, and a fourth engaging member that is fixed to the second side plate, has a hardness H4 that is smaller than a hardness H3 of the third engaging member, and is capable of engaging with the third engaging member.

[0017] The method of manufacturing a tire according to the present application includes the steps of:

[0018] The method of manufacturing a tire according to the present application includes the steps of: preparing a mold that has a plurality of sector members that mold a tread of a tire, a first side plate that molds one of a pair of side surfaces of the tire, a first engaging member that is fixed to any of the sector members, and a second engaging member that is fixed to the first side plate, has a hardness H2 that is smaller than a hardness H1 of the first engaging member, and is capable of engaging with the first engaging member; preparing a green tire; placing the green tire in the mold; and pressurizing and heating the green tire.

[0019] The method of manufacturing a mold according to the present application includes the steps of: fixing a sector member raw material to a processing jig; machining a cavity surface of a sector member obtained from the sector member raw material and a positioning portion of a first engaging member fixed to the sector member in a state where the sector member raw material is fixed to the processing jig; fixing the first engaging member to the sector member; preparing a first side plate that molds one of a pair of side surfaces of a tire; and fixing a second engaging member to the first side plate, the second engaging member having a hardness H2 that is smaller than a hardness H1 of the first engaging member and being capable of engaging with the first engaging member.

[0020] In the mold according to the present application, the second engaging member fixed to the side plate has a hardness H2 that is smaller than a hardness H1 of the first engaging member fixed to the sector member. The second engaging member is more likely to be deformed or worn than the first engaging member. In the mold, by replacing the second engaging member that has been deformed or worn, a circumferential positional shift can be suppressed. In the mold, replacement of the first engaging member fixed to the sector member is suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 This is a cross-sectional view of a mold illustrating one embodiment of the present invention.

[0022] Figure 2 yes Figure 1 A bottom view of the mold.

[0023] Figure 3 yes Figure 1 A perspective view of the second fitting part of the mold.

[0024] Figure 4 It shows that it is fixed. Figure 3 A perspective view of a portion of the side plate of the second engaging component.

[0025] Figure 5 yes Figure 1 A three-dimensional view of the first fitting part of the mold.

[0026] Figure 6 This is an exploded view of the sector member showing the first engaging component removed from the sector member.

[0027] Figure 7 It shows that it is fixed. Figure 5 The diagram illustrates the sector-shaped component of the first card assembly.

[0028] Figure 8 It is shown Figure 1 An explanatory diagram of a portion of the cavity surface of a mold.

[0029] Label Explanation

[0030] 2: Mold; 4: Green mold; 8: Fan-shaped part; 8B: Lower surface; 10: Side plate; 14: First engaging part; 14B: Lower surface; 16: Second engaging part; 18: Groove (recess); 22: Protrusion; 24: Screw; 26: Internal thread; 28: Opening; 30: Mounting recess; 30B: Pin hole. Detailed Implementation

[0031] Hereinafter, with appropriate reference to the accompanying drawings, the present invention will be described in detail based on preferred embodiments.

[0032] exist Figure 1 and Figure 2 Mold 2 is shown in the figure. Figure 1 It shows along Figure 2 The cross-section of line segment II. In Figure 2 The bottom surface of mold 2 is shown in the image. Figure 1 The image also shows a portion of the green tire 4 disposed in the mold 2 and the air bladder 6 of the vulcanizing device. The green tire 4 is pressurized and heated within the cavity formed by the mold 2 and the air bladder 6, from which a tire is obtained.

[0033] like Figure 2As shown, the mold 2 has a ring shape. Figure 2 The circumferential direction of the mold 2 is indicated by a double-headed arrow A. Figure 1 The vertical direction of the mold 2 is the axial direction, Figure 1 The lateral direction of the mold 2 is the radial direction, and the direction perpendicular to the paper surface is the circumferential direction of the mold 2.

[0034] As shown in Figure 1 and Figure 2 , the mold 2 has a plurality of sector pieces 8, a pair of side plates 10, a pair of bead rings 12, a first clamping member 14, and a second clamping member 16.

[0035] In Figure 2 , the nine sector pieces 8 are arranged in the circumferential direction and formed in a ring shape. As shown in Figure 1 , the inner peripheral surface 8A of the ring-shaped sector piece 8 abuts against the outer peripheral surface 10A of the side plate 10. The inner peripheral surface of the side plate 10 abuts against the outer peripheral surface of the bead ring 12.

[0036] The plurality of sector pieces 8 arranged in a ring shape mold the tread of the tire. The tread is formed with a tread pattern composed of a plurality of grooves and land portions. Although not shown in Figure 1 , the cavity surface 8C of the sector piece 8 that molds the tread pattern is formed with a plurality of projections and depressions for forming the grooves and land portions.

[0037] Such a sector piece 8 preferably uses a material having excellent machinability. The sector piece 8 obtained by casting from the raw material preferably uses a material having excellent castability. Also, since it is used in the mold 2, the sector piece 8 preferably uses a material having high thermal conductivity and preferably uses a lightweight material. As the material of the sector piece 8, there is no particular limitation, but an aluminum alloy can be exemplified.

[0038] As shown in Figure 2 , each side plate 10 has a ring shape. The side plate 10 is disposed on the radially inner side of the plurality of sector pieces 8. As shown in Figure 1 , the side plate 10 on the one axial side is disposed on the lower side, and the side plate 10 on the other axial side is disposed on the upper side. The pair of side plates 10 molds the outer surface of the sidewall of the tire. From the viewpoint of durability, the side plate 10 preferably uses a material harder than the material of the sector piece 8. As the material of the side plate 10, there is no particular limitation, but a ferrous alloy such as an alloy tool steel can be exemplified.

[0039] Each bead ring 12 has a ring shape. The bead ring 12 is disposed on the radially inner side of the side plate 10. The bead ring 12 on the one axial side is disposed on the lower side, and the bead ring 12 on the other axial side is disposed on the upper side. The pair of bead rings 12 molds the outer surface of the bead portion of the tire. As the material of the bead ring 12, there is no particular limitation, but the same material as that of the side plate 10 is used.

[0040] As shown in Figure 1As shown, the first engaging member 14 is mounted and fixed to the sector 8. The first engaging member 14 has a groove 18 as a recess. The groove 18 is opened at an inner peripheral surface 14A and a lower surface 14B of the first engaging member 14. In this sector 8, the groove 18 is also opened at an inner peripheral surface 8A and a lower surface 8B of the sector 8.

[0041] The second engaging member 16 is mounted and fixed to the side plate 10 as a lower side of the first side plate. The second engaging member 16 has a fixed portion 20 fixed to the side plate 10 and a protrusion 22 protruding from an outer peripheral surface 10A of the side plate 10. In this second engaging member 16, the fixed portion 20 is mounted to the side plate 10 by a screw 24. The second engaging member 16 is only required to be positionable and fixable to the side plate 10 and detachable. The mounting structure of this second engaging member 16 is exemplified and not particularly limited.

[0042] The protrusion 22 of the second engaging member 16 is inserted into the groove 18 of the first engaging member 14. The second engaging member 16 is engaged with the first engaging member 14. By this engagement, the sector 8 to which the first engaging member 14 is fixed is positioned in the circumferential direction with respect to the side plate 10. Each sector 8 abuts against other sectors 8 adjacent in the circumferential direction. Thus, the plurality of sectors 8 are positioned in the circumferential direction with respect to the side plate 10.

[0043] A portion of the side plate 10 to which the second engaging member 16 is mounted is shown in FIG. 6. In this second engaging member 16, a side surface 20A of the fixed portion 20 abuts against an inner wall of an insertion hole 10B of the side plate 10 to be positioned in the circumferential direction. The protrusion 22 of the second engaging member 16 protrudes from the outer peripheral surface 10A of the side plate 10 to the radially outer side. The circumferential width of this protrusion 22 gradually decreases toward the front end thereof. From the viewpoint of suppressing damage and deformation of the side plate 10, the second engaging member 16 preferably uses a material softer than that of the side plate 10. Figure 3

[0044] The second engaging member 16 is engaged with the first engaging member 14. From the viewpoint of maintaining positioning accuracy, as the material of the second engaging member 16, a material hard and excellent in wear resistance is preferably used. The second engaging member 16 is composed of SCM435. The material of the second engaging member 16 is not particularly limited, but as the material, chromium-molybdenum steel can be exemplified.

[0045] A portion of the side plate 10 to which the second engaging member 16 is mounted is shown in FIG. 6. In this second engaging member 16, a side surface 20A of the fixed portion 20 abuts against an inner wall of an insertion hole 10B of the side plate 10 to be positioned in the circumferential direction. The protrusion 22 of the second engaging member 16 protrudes from the outer peripheral surface 10A of the side plate 10 to the radially outer side. The circumferential width of this protrusion 22 gradually decreases toward the front end thereof. From the viewpoint of suppressing damage and deformation of the side plate 10, the second engaging member 16 preferably uses a material softer than that of the side plate 10. Figure 4 A portion of the side plate 10 to which the second engaging member 16 is mounted is shown in FIG. 6. In this second engaging member 16, a side surface 20A of the fixed portion 20 abuts against an inner wall of an insertion hole 10B of the side plate 10 to be positioned in the circumferential direction. The protrusion 22 of the second engaging member 16 protrudes from the outer peripheral surface 10A of the side plate 10 to the radially outer side. The circumferential width of this protrusion 22 gradually decreases toward the front end thereof. From the viewpoint of suppressing damage and deformation of the side plate 10, the second engaging member 16 preferably uses a material softer than that of the side plate 10.

[0046] Figure 5 ​​The diagram shows a first engaging member 14. A groove 18 of the first engaging member 14 opens on its inner circumferential surface 14A. The groove 18 also opens on its lower surface 14B. The width of the groove 18 is constant except for the opening 28 on the inner circumferential surface 14A. In the opening 28, the width of the groove 18 gradually increases towards the inner circumferential surface 14A in the radial direction inwards. The first engaging member 14 has a pair of threaded holes 14C and a pair of pin holes 14D.

[0047] The first engaging member 14 engages with the second engaging member 16. From the viewpoint of maintaining positioning accuracy, it is preferable to use a hard material with excellent wear resistance as the material for the first engaging member 14. The first engaging member 14 is made of SKD11. The material of the first engaging member 14 is not particularly limited, but alloy tool steel can be used as an example.

[0048] like Figure 6 As shown, a mounting recess 30 with openings on the inner circumferential surface 8A and the lower surface 8B is formed in the sector member 8. A pair of internal threads 30A and a pair of pin holes 30B are formed in the mounting recess 30. A first engaging member 14 is disposed in this mounting recess 30. A pair of external threads 32 pass through threaded holes 14C and are screwed into the internal threads 30A. A pair of retaining pins 34 are inserted into pin holes 14D and pin holes 30B, respectively. Thus, the first engaging member 14 is mounted and fixed to the sector member 8.

[0049] In this mold 2, a retaining pin 34 is inserted into a pair of pin holes 30B to position the first engaging member 14. The pair of pin holes 30B function as positioning parts for the first engaging member 14 in the sector member 8. These positioning parts are not particularly limited as long as they can position the first engaging member 14 in the sector member 8. For example, the wall surface 30C of the mounting recess 30 can also position the first engaging member 14.

[0050] exist Figure 7 The diagram shows a sector-shaped member 8 and a first engaging member 14 fixed to the sector-shaped member 8. A groove 18 of the first engaging member 14 opens on its inner circumferential surface 14A. The groove 18 also opens on its lower surface 14B. In other words, the groove 18 opens on the inner circumferential surface 8A and the lower surface 8B of the sector-shaped member 8.

[0051] exist Figure 8 It shows Figure 1 A portion of the cavity surface 8C of the fan-shaped part 8 and the cavity surface 10C of the side plate 10 in the mold 2. In this mold 2, the inner peripheral surface 8A of the fan-shaped part 8 abuts against the outer peripheral surface 10A of the side plate 10.

[0052] The cavity surface 8C has a surface 36 and a plurality of recesses 38 recessed from the surface 36. Grooves and lands of a tread pattern are formed by the surface 36 and the recesses 38. In the mold 2, the cavity surface 10C of the side plate 10 also has a surface 40 and recesses 42 recessed from the surface 40. In the mold 2, a concave-convex shape continuous with the lands or grooves formed in the tread is also formed on the outer surface of the tire side of the tire.

[0053] A method of manufacturing a tire using the mold 2 will be described. The mold 2 is prepared (step 1). The mold 2 is installed in a vulcanization device not shown. A green tire 4 is prepared (step 2). The vulcanization device separates the pair of side plates 10 in the up-down direction. The vulcanization device moves each sector 8 toward the radially outer side. Each sector 8 is separated from each other. In this way, the mold 2 is opened (step 3).

[0054] The green tire 4 is put into the opened mold 2 (step 4). The vulcanization device brings the pair of side plates 10 close. The vulcanization device moves each sector 8 toward the radially inner side. The first engaging member 14 installed in the sector 8 engages with the second engaging member 16 of the side plate 10. Each sector 8 abuts against the other sector 8 adjacent in the circumferential direction. In this way, as shown in FIG. 1, the mold 2 is closed (step 5). The green tire 4 is pressurized and heated in the mold 2 (step 6). In this way, a tire is obtained from the green tire 4. Figure 1

[0055] Here, a method of manufacturing the sector 8 will be described. Although not shown, a sector raw material is prepared (step 1'). The sector raw material is installed and fixed to a processing jig (step 2'). In the state of being fixed to the processing jig, the cavity surface 8C and the mounting recess 30 of the sector 8 are cut and processed in the sector raw material (step 3'). In this process (step 3'), the pair of pin holes 30B (refer to FIG. 3) as the positioning portion of the first engaging member 14 is processed together with the cavity surface 8C by cutting and processing or the like. The sector 8 is obtained by processing the sector raw material (step 4'). The first engaging member 14 is installed and fixed to the sector 8 (step 5'). Figure 6

[0056] Similarly, a method of manufacturing the side plate 10 will be described. Although not shown, a side plate raw material is prepared (step 1"). The side plate raw material is installed and fixed to a processing jig (step 2"). In the state of being fixed to the processing jig, the insertion hole 10B as the positioning portion is processed together with the cavity surface 10C in the side plate raw material by cutting and processing or the like (step 3"). The side plate 10 is obtained by processing the side plate raw material (step 4"). The second engaging member 16 is installed and fixed to the side plate 10 (step 5").

[0057] ​​The mold 2 has a first engaging member 14 fixed to at least one of the plurality of segments 8 and a second engaging member 16 fixed to the side plate 10. The second engaging member 16 is engageable with the first engaging member 14. By the engagement, the segments 8 are positioned in the circumferential direction with respect to the side plate 10.

[0058] The second engaging member 16 has a hardness H2 smaller than the hardness Hl of the first engaging member 14. In the mold 2, the second engaging member 16 is easily abraded and damaged compared with the first engaging member 14. In the mold 2, the abrasion and damage of the first engaging member 14 are suppressed. In the mold 2, replacement of the first engaging member 14 fixed to the segments 8 can be suppressed.

[0059] Further, the hardness in the present application is compared using a value measured at a test force of 29.4 (kN) with a diameter of 10 mm of a presser for super hard alloy as a reference of "Brinell Hardness Test - Test Method" of JIS Z 2243.

[0060] In the mold 2, the segments 8 have a hardness smaller than that of the side plate 10. Replacement of the first engaging member 14 fixed to such segments 8 easily damages the positional accuracy of the first engaging member 14. The second engaging member 16 having a hardness H2 smaller than the hardness Hl of the first engaging member 14 is suitable for the mold 2 having such segments 8.

[0061] In the mold 2, the first engaging member 14 has a groove 18 as a recessed portion. The second engaging member 16 has a protrusion 22 engageable with the groove 18. The second engaging member 16 having the protrusion 22 protruding from the side plate 10 is easily subjected to an external force. The first engaging member 14 can be fixed in a manner not to protrude from the segments 8. The first engaging member 14 is less likely to be subjected to an external force compared with the second engaging member 16. In the mold 2, replacement of the first engaging member 14 can be further suppressed.

[0062] Further, in the mold 2, the groove 18 is formed in the first engaging member 14 fixed to the segments 8, but is not limited thereto. It can be that the groove 18 is formed in the second engaging member 16 fixed to the side plate 10 and the protrusion 22 is formed in the first engaging member 14.

[0063] In particular, in the mold 2 in which the segments 8 have a hardness smaller than that of the side plate 10, the positional accuracy of the first engaging member 14 is easily damaged by replacement of the first engaging member 14. In such a mold 2, it is preferable that the first engaging member 14 has the groove 18 as a recessed portion and the second engaging member 16 has the protrusion 22 engageable with the groove 18.

[0064] In this mold 2, multiple sector-shaped parts 8 are arranged vertically along the axial direction, and a side plate 10 is disposed on the lower side of the multiple sector-shaped parts 8. The groove 18 of the first engaging part 14 opens on its lower surface 14B. In this mold 2, foreign objects are less likely to remain in the groove 18. When the green tire 4 is inserted into the mold 2 and removed from the mold 2, foreign objects are also less likely to remain in the groove 18. In this mold 2, the positional displacement between the sector-shaped parts 8 and the side plate 10 caused by the residue of foreign objects is suppressed.

[0065] In this mold 2, the second engaging member 16 is detachably mounted to the side plate 10. By replacing the second engaging member 16, positional misalignment can be suppressed. In particular, in mold 2 where the hardness of the fan-shaped member 8 is less than that of the side plate 10, replacing the first engaging member 14 of the fan-shaped member 8 can be suppressed. This mold 2 can suppress positional misalignment between the fan-shaped member 8 and the side plate 10 for a long period of time.

[0066] From the viewpoint of suppressing wear or damage to the first engaging member 14, the Brinell hardness H1 is preferably 600 HBW or higher, more preferably 620 HBW or higher, and particularly preferably 640 HBW or higher. There is no preferred upper limit for this hardness H1, but it is, for example, 660 HBW or lower. The material of the first engaging member 14 is preferably alloy tool steel.

[0067] From the viewpoint of suppressing wear or damage to the second engaging member 16, the Brinell hardness H2 is preferably 200 HBW or higher, more preferably 220 HBW or higher, and particularly preferably 240 HBW or higher. On the other hand, from the viewpoint of suppressing wear and damage to the engaged first engaging member 14, the hardness H2 is preferably 300 HBW or lower, more preferably 280 HBW or lower, and particularly preferably 260 HBW or lower. The material of the second engaging member 16 is preferably chromium-molybdenum steel.

[0068] From the viewpoint of suppressing wear and damage to the first engaging member 14, the difference between hardness H1 and hardness H2, H1-H2, is preferably 350 HBW or more, more preferably 370 HBW or more, and particularly preferably 390 HBW or more. On the other hand, the second engaging member 16, which has a large hardness difference, is prone to wear or damage. From the viewpoint of suppressing such wear or damage, this difference H1-H2 is preferably 450 HBW or less, more preferably 430 HBW or less, and particularly preferably 410 HBW or less.

[0069] like Figure 8 As shown, in this mold 2, the recess 42 of the cavity surface 10C of the side plate 10 is formed continuously with the recess 38 of the cavity surface 8C of the sector member 8. In this mold 2, a concave-convex shape is formed on the outer surface of the tire sidewall that is continuous with the land or groove formed on the tread of the tire. In such a tire, circumferential misalignment between the sector member 8 and the side plate 10 will impair the tire's appearance. This mold 2 is suitable for manufacturing such tires.

[0070] Although not shown, the mold 2 can also have a third engaging member fixed to any one of the plurality of segments 8, and a fourth engaging member fixed to the other side plate 10 on the upper side. The fourth engaging member has a hardness H4 that is less than the hardness H3 of the third engaging member. By having the third and fourth engaging members, the position of the segments 8 in the circumferential direction of the side plate 10 on the upper side as the second side plate can be inhibited from shifting.

[0071] For example, a third engaging member identical to the first engaging member 14 is installed and fixed in a manner that opens on the upper surface of the segment 8 and the inner circumferential surface 8A above. A fourth engaging member identical to the second engaging member 16 is installed and fixed to the other side plate 10.

[0072] The third engaging member can be fixed to the segment 8 on which the first engaging member 14 is fixed, or to another segment 8. For example, the third engaging member can be fixed to the segment 8 that is farthest in the circumferential direction from the segment 8 on which the first engaging member 14 is fixed. Also, the first engaging member 14 or the third engaging member can be fixed to each of the plurality of segments 8, further, to all of the segments 8. The second engaging member 16 or the fourth engaging member that engages with the plurality of first engaging members 14 or the third engaging member can be fixed to the side plate 10.

[0073] In the manufacturing method of the mold 2, from the viewpoint of easily improving the position accuracy of the first engaging member 14, it is preferable to machine the cavity surface 8C and the pair of pin holes 30B in a state in which the segment raw material is fixed to the segment machining jig. Also, from the viewpoint of easily improving the position accuracy of the second engaging member 16, it is preferable to machine the cavity surface 10C and the insertion hole 10B as the positioning portion in a state in which the side plate raw material is fixed to the side plate machining jig.

[0074] [EMBODIMENT]

[0075] Hereinafter, the effects of the present application will be clarified by an embodiment, but the present application should not be interpreted limitatively based on the description of the embodiment.

[0076] [EMBODIMENT]

[0077] A mold of Figure 1 was prepared. The mold had nine segments. A first engaging member was fixed to the lower side of the first segment arranged in the circumferential direction. In addition, a third engaging member identical to the first engaging member was fixed to the upper side of the fifth segment arranged in the circumferential direction. A second engaging member that engaged with the first engaging member was fixed to one of the pair of side plates (the lower side plate). A fourth engaging member identical to the second engaging member that engaged with the third engaging member was fixed to the other (the upper side plate). The other parts were identical to the existing mold. The mold was used to manufacture 1400 tires.

[0078] [Example]

[0079] In addition to using the existing mold, 1400 tires were manufactured in the same manner as the example.

[0080] [Evaluation of Position Deviation]

[0081] Fifteen tires were randomly selected from among every 100 of the tires manufactured in the example. For these tires, the circumferential position deviation was measured at the boundary between the portion molded by the sector and the portion molded by the side plate. Similarly, for the tires of the comparative example, the circumferential position deviation was also measured. The results are shown in Table 1. In Table 1, the maximum value, the minimum value, and the average value in the example and the comparative example are expressed as indices with the amount of position deviation in the comparative example being 100. The smaller the index, the smaller the amount of position deviation.

[0082] Table 1 Evaluation Results

[0083]

[0084] As shown in Table 1, the manufacturing method using the mold of the example was evaluated more highly than the manufacturing method of the comparative example. From this evaluation result, the superiority of the present application is apparent.

[0085] Industrial Applicability

[0086] The method described above can be widely applied to the manufacture of tires using a mold having a ring-shaped sector and a pair of side plates.

Claims

1. A mold having: a plurality of segments that form a tread of a tire; a first side plate that forms one of a pair of outer surfaces of a side of the tire and that is located radially inward of the segments; a first engaging member that is fixed to an arbitrary segment; and a second engaging member that is fixed to the first side plate, has a hardness H2 that is smaller than a hardness Hl of the first engaging member, and is capable of engaging with the first engaging member.

2. The mold according to claim 1, wherein the hardness of the segment to which the first engaging member is fixed is smaller than the hardness of the first side plate.

3. The mold according to claim 1 or 2, wherein the first engaging member has a recess, and the second engaging member has a protrusion that engages with the recess.

4. The mold according to claim 3, wherein the plurality of segments are arranged with an axial direction as a vertical direction, the first side plate is arranged on a lower side of the plurality of segments, and the recess opens at a lower surface of the first engaging member.

5. The mold according to claim 1 or 2, wherein the second engaging member is detachably attached to the first side plate.

6. The mold according to claim 1 or 2, wherein a difference Hl-H2 between the hardness Hl and the hardness H2 is 350 HBW or more and 450 HBW or less.

7. The mold according to claim 1 or 2, wherein a material of the first engaging member is alloy tool steel.

8. The mold according to claim 1 or 2, wherein a material of the second engaging member is chromium-molybdenum steel.

9. The mold according to claim 1 or 2, having: a second side plate that forms the other of the pair of outer surfaces of the side of the tire; a third engaging member that is fixed to an arbitrary segment; and a fourth engaging member that is fixed to the second side plate, has a hardness H4 that is smaller than a hardness H3 of the third engaging member, and is capable of engaging with the third engaging member.

10. A method of manufacturing a tire, the method of manufacturing a tire including the steps of: preparing a mold having a plurality of segments that form a tread of a tire, a first side plate that forms one of a pair of outer surfaces of a side of the tire and that is located radially inward of the segments, a first engaging member that is fixed to an arbitrary segment, and a second engaging member that is fixed to the first side plate, has a hardness H2 that is smaller than a hardness Hl of the first engaging member, and is capable of engaging with the first engaging member; preparing a green tire; placing the green tire in the mold; and pressurizing and heating the green tire.

11. A method of manufacturing a mold, the method of manufacturing a mold including the steps of: fixing a segment raw material to a processing jig; processing a positioning portion of a first engaging member that is fixed to a segment obtained from the segment raw material and a cavity surface of the segment in a state in which the segment raw material is fixed to the processing jig; fixing the first engaging member to the segment. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A first side plate to be prepared to mold one side of the outer surface of a pair of sidewalls of a tire, the first side plate being located radially inward of the sector piece; and A second engaging member is fixed to the first side plate, the second engaging member having a hardness H2 that is less than the hardness H1 of the first engaging member and being capable of engaging with the first engaging member.

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