Mold for molding tire

Abstract

To provide a mold for molding a tire capable of reducing a driving force required for driving segments in an initial stage of tire demolding.SOLUTION: A mold 100 for molding a tire comprises: a tread molding section 3 having a mold section 40 and divided into segments 4 aligned in a circumferential direction; and an annular ring 7 for opening and closing the tread molding section 3 in a radial direction. Each segment 4 is disposed radially outward of the mold section 40 and includes a first rail section 45 that engages with the ring 7 and is inclined radially inward. The ring 7 has, on an inner surface side, a second rail section 74 that engages with the first rail section 45 of each segment 4 and extends along the first rail section 45. In a state where the ring 7 closes the tread molding section 3, among radial distances between the first rail section 45 and the second rail section 74, a distance on one axial end side is smaller than that on the other end side, and among radial inward inclination angles between the first rail section 45 and the second rail section 74, an inclination angle on one axial end side is smaller than that on the other end side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire mold. [Background technology]

[0002] Conventionally, as a tire molding mold used when manufacturing a tire by vulcanizing and molding an unvulcanized raw tire, there has been known a tire molding mold in which the annular tread molding portion (tread mold) that molds the tire tread is divided into a plurality of segments arranged in the circumferential direction, and each segment is configured to open and close by moving in the radial direction (see, for example, Patent Documents 1 to 3).

[0003] However, with the above-mentioned conventional tire molding molds, when the tire is released from the tread molding section after vulcanization molding, each segment moves radially outward while maintaining its orientation relative to the tire tread. This causes the tread design surface that molds the tread of each segment, i.e., the entire surface of the mold, to simultaneously peel off from the tread, posing a problem in that a large driving force is required to drive the segments until they are released from the tire.

[0004] For example, in the initial stage of tire demolding, it is necessary to peel the segment mold from the tread and also to remove the segment protrusions (sipe molds) corresponding to the pattern from the tire's design surface. Therefore, when the segment mold is peeled from the tread, a large driving force is required to release the adhesion between the mold surface and the tread. Furthermore, there was a problem in that a large driving force was required to drive the segment due to undercut resistance when the segment protrusions corresponding to this pattern were removed from the tire's design surface pattern until the segment was released from the tire.

[0005] Patent Document 4 discloses a tire molding mold that includes an annular tread molding portion divided into multiple segments arranged in the circumferential direction, and a tilting mechanism that tilts the segments radially outward when the tread molding portion is opened radially outward, the tilting mechanism returning the tilt of the segments to their original position after the tread molding portion is opened. With this tire molding mold, it is said that by tilting the segments radially outward when the tread molding portion is opened radially outward, it is possible to reduce the driving force required to drive the segments in the initial stage of tire demolding. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-326332 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-334740 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-149079 [Patent Document 4] Japanese Patent Publication No. 2023-68580 Summary of the Invention [Problem to be solved by the invention]

[0007] If the segment opening speed (the moving speed of the segments as they open) when the mold surface and the tread are released from tight contact, it can shorten the life of the mold's sipes or damage the tread (for example, tearing of the rubber in the sipe grooves in the tread). Therefore, adjusting the segment opening speed when the mold surface and the tread (tread surface) are released from tight contact is important. However, with the prior art such as those disclosed in Patent Documents 1 to 4, it was sometimes difficult to adjust the balance between the segment opening speed (the moving speed of the segments as they open) when the mold surface and the tread are released from tight contact and the segment opening speed after the mold surface and the tread are released from tight contact. For example, it was difficult to simultaneously prevent shortening of the sipe life, avoid damage to the tread, and reduce the process time for tire building by slowing the segment opening speed when the mold surface and the tread are released from tight contact (initial stage of demolding) and increasing the segment opening speed after the mold surface and the tread are released from tight contact. Therefore, it is desirable to provide a tire mold that can slow the opening speed of the segments when releasing the adhesion between the mold surface and the tread.

[0008] The present invention has been made in consideration of the above circumstances, and its object is to provide a tire molding mold that can slow the opening speed of the segments when releasing the adhesion between the mold surface and the tread. [Means for solving the problem]

[0009] In order to achieve the above object, the tire mold according to the present invention comprises: a circular tread molding section having a mold section for forming a tire tread and divided into a plurality of segments arranged in a circumferential direction; an annular outer ring that is disposed radially outside the tread molding portion and moves along the axial direction of the tread molding portion to move the segments in the radial direction, thereby opening and closing the tread molding portion in the radial direction, The segment is and disposed radially outward of the mold portion, a first rail portion on an outer surface in the radial direction, the first rail portion engaging with the outer ring, extending along the axial direction and inclined inward in the radial direction; The outer ring is The axis of the tire overlaps with the axis of the tread molding portion, a second rail portion on an inner surface thereof, the second rail portion engaging with the first rail portion of each of the segments and extending along the first rail portion; When the outer ring closes the tread molding portion, the radial distance between the first rail portion and the second rail portion is such that the distance on one end side in the axial direction is smaller than the distance on the other end side, Of the radially inward inclination angles of at least one of the first rail portion and the second rail portion, the inclination angle of the region on the one end side is smaller than the inclination angle of the region on the other end side.

[0010] In the tire mold according to the present invention, The first rail portion is a first upper rail portion which is an area on the one end side; a first lower rail portion which is the region on the other end side, The inclination angle of the first upper rail portion may be smaller than the inclination angle of the first lower rail portion.

[0011] In the tire mold according to the present invention, The second rail portion is a second upper rail portion which is an area on the one end side; a second lower rail portion which is the region on the other end side, The inclination angle of the second upper rail portion may be smaller than the inclination angle of the second lower rail portion.

[0012] In the tire mold according to the present invention, The second rail portion is a second upper rail portion which is an area on the one end side; a second lower rail portion which is the region on the other end side, The second upper rail portion may be a rod-shaped member extending along the circumferential direction of the tread mold portion or along a tangential direction to the circumferential direction.

[0013] In the tire mold according to the present invention, The length of the region on the one end side in the axial direction may be shorter than the length of the region on the other end side.

[0014] In the tire mold according to the present invention, When the segments are opened, the end portion on the one end side may be inclined outward in the radial direction.

[0015] In the tire mold according to the present invention, A lower surface portion of the radially outer region at the lower end of the segment may be located closer to one end in the axial direction than a lower surface portion of the radially inner region. [Effects of the Invention]

[0016] According to the present invention, the opening speed of the segments when the tread is released from the mold surface can be slowed down. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view of a tire mold according to an embodiment of the present invention as seen from the front. [Figure 2] FIG. 2 is a cross-sectional view of a tread molding portion in a plan view. [Figure 3] FIG. 2 is a cross-sectional front view of a main part of the tire mold in a closed state. [Figure 4] FIG. 2 is a cross-sectional front view of a main part of a tire mold in a state where the mold is beginning to open. [Figure 5] FIG. 5 is a cross-sectional front view of the main parts of the tire mold in a state further opened than the state shown in FIG. 4. [Figure 6] FIG. 6 is a cross-sectional front view of the main parts of the tire mold in a state further opened than the state shown in FIG. 5. [Figure 7]FIG. 7 is a cross-sectional front view of the main parts of the tire mold in a state further opened than the state shown in FIG. 6. [Figure 8] FIG. 8 is a cross-sectional view taken along the line VIII-VIII in FIG. 7. [Figure 9] 9 is a cross-sectional view taken along the line IX-IX in FIG. 7. [Figure 10] FIG. 10 is a cross-sectional front view of a main part of a tire mold according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0018] A tire mold according to an embodiment of the present invention will be described with reference to the drawings.

[0019] (First embodiment) FIG. 1 shows a cross-sectional front view of a tire mold 100 (hereinafter sometimes referred to as mold 100) according to this embodiment.

[0020] (Summary) The mold 100 is used to manufacture a tire 200 by molding a green tire, which is mainly made of unvulcanized (before vulcanization) synthetic rubber, into a predetermined shape while vulcanizing it.

[0021] The mold 100 has a mold section 40 that forms the tread of the tire 200, and is equipped with an annular tread molding section 3 divided into a plurality of segments 4 arranged circumferentially, and an outer ring 7 that is arranged radially outside the ring of the tread molding section 3 and moves along the axial direction of the ring of the tread molding section 3 to move the segments 4 radially, thereby opening and closing the tread molding section 3 radially.

[0022] The segments 4 are positioned radially outward from the mold section 40, and have on their radially outer surface a first rail portion 45 that engages with the outer ring 7, extends along the axial direction, and is inclined radially inward; the outer ring 7 has an axis that overlaps with the axis G of the ring of the tread molding section 3, and has on its inner surface a second rail portion 74 that engages with the first rail portion 45 of each segment 4 and follows the first rail portion 45; when the outer ring 7 closes the tread molding section 3, the radial distance between the first rail portion 45 and the second rail portion 74 at the upper end side (an example of one end side) in the axial direction is smaller than the distance at the lower end side (an example of the other end side); and the radially inward inclination angle of at least one of the first rail portion 45 and the second rail portion 74 is smaller than the inclination angle of the upper end side region.

[0023] 1, as an example of the inclination angle, the inclination angle of the first rail portion 45 (first lower rail portion 45b) is indicated by angle α, and the inclination angle of the second rail portion 74 (second lower rail portion 74b) is indicated by angle β.

[0024] In the mold 100, it is possible to slow the opening speed of the segments 4 when the surface of the mold section 40 (the surface facing the tread) and the tread (tread surface) are released from tight contact, i.e., in the initial stage of release of the tire 200. More specifically, in the mold 100, of the radially inward inclination angles of at least one of the first rail section 45 and the second rail section 74, the inclination angle of the upper end region is smaller than the inclination angle of the lower end region. Therefore, the segments 4 open radially as the outer ring 7 moves, and the speed at which the segments 4 move away from the tread of the tire 200 in the initial stage of release of the mold section 40 from the tread of the tire 200 (i.e., the opening speed) is slower than the opening speed after the mold section 40 has been released from the tread of the tire 200.

[0025] (Detailed explanation) The mold 100 will be described in detail below.

[0026] 1, the mold 100 includes a lower container 1, an upper container 2, a tread molding portion 3, and an outer ring 7 (hereinafter referred to as the ring 7). As described above, the tread molding portion 3 is formed in an annular shape.

[0027] Hereinafter, the direction along the axis G of the ring of the tread molding portion 3 will be referred to as the axial direction. The circumferential direction of the ring of the tread molding portion 3 and the same direction will be simply referred to as the circumferential direction. The radial direction of the ring of the tread molding portion 3 and the same direction will be simply referred to as the radial direction, and the outer side in the radial direction may be simply referred to as the outer side, and the inner side in the radial direction may be simply referred to as the inner side. In the axial direction, the direction facing the upper container 2 as seen from the lower container 1 will be referred to as the upper side, upward, or top, and the direction facing the lower container 1 as seen from the upper container 2 will be referred to as the lower side, downward, or bottom. In this embodiment, a front view refers to a viewpoint when viewed along the radial direction. In this embodiment, a plan view or a top view refers to a viewpoint when viewed from above downward along the axial direction.

[0028] The lower container 1 is a seat for the mold 100. The upper container 2 and the tread molding section 3 are placed on the lower container 1. The lower container 1 has a plate section 10 and a lower sidewall molding section 11 placed on the upper surface of the plate section 10.

[0029] The upper container 2 has a plate portion 20 and an upper sidewall molding portion 21 fixed to the underside of the plate portion 20. A ring 7 is suspended and supported by the upper container 2. In this embodiment, the ring 7 is suspended from the upper container 2 with its upper end fixed to a position outside the upper sidewall molding portion 21. The upper container 2 is capable of moving up and down relative to the lower container 1 along the axial direction.

[0030] The lower sidewall molding portion 11 and the upper sidewall molding portion 21 are molds that form the side surfaces (sidewalls) of the tire 200. The lower sidewall molding portion 11 and the upper sidewall molding portion 21 are formed in an annular shape that is coaxial with the tread molding portion 3. The upper surface of the lower sidewall molding portion 11 and the lower surface of the upper sidewall molding portion 21 are design surfaces that mold the side surfaces of the tire 200.

[0031] The tread molding section 3 is a unit including a mold that forms the tread surface of the tire 200. The inner surface of the tread molding section 3 is a design surface that forms the tread surface of the tire 200. The tread molding section 3 is placed directly on the upper surface of the plate section 10 of the lower container 1.

[0032] Fig. 2 shows a cross-sectional plan view (top view) of the tread molding portion 3. The tread molding portion 3 has an annular shape in plan view. As shown in Fig. 2, the tread molding portion 3 is divided into a plurality of segments 4 arranged in the circumferential direction.

[0033] The tread molding portion 3 may be divided into, for example, 5 to 90 segments 4 in the circumferential direction. As shown in FIG. 1, the segments 4 may be placed directly on the upper surface of the plate portion 10 of the lower container 1. FIG. 2 illustrates an example in which the tread molding portion 3 is divided into nine segments 4 each having the same circumferential length. The inner surface of the segments 4 is the design surface of the tread molding portion 3. Hereinafter, the inner surface of the segments 4 may be referred to as the design surface of the segments 4.

[0034] The segment 4 is movable between a closed position (see FIG. 2 ) in which the design surface of the segment 4 is continuously connected to the design surface of another segment 4 adjacent in the circumferential direction, and an open position in which the design surface of the segment 4 is discontinuous with the design surface of another adjacent segment 4. In other words, the open position of the segment 4 is a position outside the closed position of the segment 4. The segment 4 is movable, for example, in the radial direction between the open position and the closed position.

[0035] 3 to 7 show cross-sectional views of the main parts of the mold 100 as viewed along the circumferential direction of the mold 100. FIG.

[0036] As shown in Figures 1 and 3 to 7, the ring 7 is disposed on the outer side and above the tread molding portion 3. The ring 7 is formed in an annular shape in a plan view and engages with each of the segments 4. The ring 7 moves the segments 4 between a closed position (see Figure 3) and an open position (see Figures 5 to 7). The ring 7 is movable between a holding position (see Figure 3) in which the segments 4 are held in the closed position, and a release position (see Figures 4 to 7) in which the segments 4 are in the open position. Note that Figure 4 shows a cross section of the mold 100 when the segments 4 begin to open, i.e., at the beginning of demolding of the tire 200. Figures 5 to 7 show the process of the segments 4 opening in this order.

[0037] In this embodiment, the ring 7 rises and falls as the upper container 2 rises and falls. The ring 7 may be raised and lowered by an elevator (not shown). In this embodiment, the holding position is the lowest position of the ring 7. The release position is a position where the ring 7 is higher than the holding position. The ring 7 and the operation associated with the engagement between the ring 7 and the segment 4 will be described later.

[0038] As shown in FIGS. 3 to 7 , the segment 4 has a mold section 40 whose inner surface is a design surface that forms the tread surface of the tire 200, a holder 41 that supports the mold section 40, and a container 42 that holds the holder 41. The holder 41 and the container 42 may be integrated. In the segment 4, the mold section 40, the holder 41, and the container 42 are arranged in this order from the inside to the outside in the radial direction. The mold section 40, the holder 41, and the container 42 are fixed by bolts or the like to form an integrated segment 4.

[0039] The segment 4 is disposed inside and below the ring 7. The inner surfaces of the upper and lower ends of the segment 4 face the outer surfaces of the upper sidewall molding portion 21 and the lower sidewall molding portion 11, respectively. The segment 4 may move between an open position and a closed position while being placed on the upper surface of the plate portion 10 of the lower container 1. Note that the segment 4 may be spaced apart, i.e., spaced apart from, the upper surface of the plate portion 10 in the open position.

[0040] 3 to 7, the mold section 40 has, on its design surface, protrusions that form grooves in the tread of the tire 200 and protrusions that form sipes. The protrusions on the design surface of the mold section 40 may be provided in any shape to match the desired shape of the tread or the shape of the sipes. The circumferential ends of the mold section 40 are shaped to follow the ends of the adjacent mold sections 40.

[0041] 3 to 7, the outer surface 44 of the segment 4 (in this embodiment, the container 42) is an inclined surface in which the upper end side of the segment 4 is positioned more inward than the lower end side. The outer surface 44 is an arc-shaped surface that follows the circumferential direction when viewed from above (see FIG. 2).

[0042] A first rail portion 45 (an example of a first rail portion) is formed on the outer surface 44, extending approximately linearly in the axial direction from the lower end to the upper end of the outer surface 44. In other words, the first rail portion 45 is inclined so that the upper end is located radially inward relative to the lower end. Hereinafter, the inclination angle with respect to the axial direction (angle β shown in FIG. 1 ) in a state in which the first rail portion 45 is inclined so that the upper end is located radially inward relative to the lower end will be simply referred to as the inclination angle of the first rail portion 45, etc. The inclination angle of the upper end region of the first rail portion 45 is smaller than the inclination angle of the lower end region. The axial length of the upper end region of the first rail portion 45 may be shorter than the axial length of the lower end region.

[0043] In this embodiment, the first rail portion 45 is a guide groove having a so-called T-slot (dovetail) shape (T-shape) in which the circumferential width of the opening at the top of the groove (an opening formed on the outer surface 44 along the axial direction, an outer portion in the radial direction) is smaller than the circumferential width of the bottom portion of the groove (an inner portion in the radial direction) (see FIG. 2). As shown in FIGS. 3 to 7, the first rail portion 45 engages with the ring 7. The engagement between the first rail portion 45 and the ring 7 will be described later.

[0044] In this embodiment, the inclination angle of the first rail portion 45 (angle β shown in Figure 1) refers to the inclination angle of the lower surface (surfaces 45as, 45bs, surfaces facing downward in the axial direction and inward in the radial direction) of the horizontal bar portion of the T-shaped first rail portion 45, which is a T-shaped guide groove.

[0045] In this embodiment, the first rail portion 45 has a first upper rail portion 45a which is an upper end region and a first lower rail portion 45b which is a lower end region. The first upper rail portion 45a and the first lower rail portion 45b may be an integrated rail or may be separate rails.

[0046] In this embodiment, the first upper rail portion 45a and the first lower rail portion 45b are illustrated as having rail portions that are integrally continuous.

[0047] The first upper rail portion 45a may be formed linearly. The first lower rail portion 45b may also be formed linearly. The inclination angle of the first upper rail portion 45a is smaller than the inclination angle of the first lower rail portion 45b. The length of the first upper rail portion 45a along the axial direction may be shorter than the length of the first lower rail portion 45b along the axial direction.

[0048] In this embodiment, the first upper rail portion 45a is the upper end region of the underside of the T-shaped crossbar portion of the first rail portion 45, where the inclination angle is smaller than that of the lower end side (i.e., the first lower rail portion 45b).

[0049] The inclination angle of the first upper rail portion 45a is preferably 3° or more and 15° or less. The inclination angle of the first lower rail portion 45b is preferably 10° or more and 30° or less. The inclination angle of the first upper rail portion 45a is preferably 3° or more and 15° or less smaller than the inclination angle of the first lower rail portion 45b.

[0050] A chamfered portion 4a may be formed on the outer portion of the lower part of the segment 4 (in this embodiment, the outer portion of the lower surface of the container 42) such that the gap between the lower surface of the segment 4 and the upper surface of the plate portion 10 increases toward the outside. That is, the lower surface portion of the radially outer region at the lower end of the segment 4 may be located closer to the upper end in the axial direction than the lower surface portion of the radially inner region. This makes it easier for the upper end of the segment 4 to tilt outward.

[0051] 1, the ring 7 has a cylindrical shape with the axis G as the center of the cylinder. The ring 7 engages with an outer surface 44 or a first rail portion 45 of a holder 41 which is the outer portion of the segment 4.

[0052] 3 to 7, the ring 7 has an inner peripheral portion 72 on which an inner ring inclined surface 73 is formed, which faces inward and slopes so that the diameter gradually decreases upward. The inner ring inclined surface 73 faces inward and is an arc-shaped surface that slopes linearly with respect to the axial direction and follows the circumferential direction so that the upper end side is located more inward than the lower end side.

[0053] A rail-shaped second rail portion 74 is disposed on the ring inner peripheral portion 72 along the axial direction and along the ring inner inclined surface 73. In other words, the second rail portion 74 is inclined so that its upper end is positioned radially inward relative to its lower end. In this embodiment, the second rail portion 74 extends radially inward from the ring inner inclined surface 73. Hereinafter, the inclination angle (angle α shown in FIG. 1 ) of the second rail portion 74 with respect to the axial direction in a state in which the second rail portion 74 is inclined so that its upper end is positioned radially inward relative to its lower end will be simply referred to as the inclination angle of the second rail portion 74, etc.

[0054] The second rail portion 74 may be molded integrally with the ring inner periphery portion 72, or may be separate from the ring inner periphery portion 72 and fixed to the ring inner periphery portion 72 with bolts or the like.

[0055] The inclination angle of the upper end region of the second rail portion 74 is smaller than the inclination angle of the lower end region. The length of the upper end region of the second rail portion 74 along the axial direction may be shorter than the length of the lower end region of the second rail portion 74 along the axial direction.

[0056] The second rail portions 74 are arranged in the circumferential direction at the same intervals as the intervals between adjacent segments 4 in the circumferential direction, and in the same number as the segments 4.

[0057] The second rail portion 74 may have a T-shaped cross section when viewed along the extension direction. In other words, the second rail portion 74 may have a wider circumferential width on the side away from the ring inner circumferential portion 72 (the radially inner portion) than on the side closer to the ring inner circumferential portion 72 (the radially outer portion). FIGS. 8 and 9 show cross-sectional views of an upper end portion of the second rail portion 74 (a second upper rail portion 74a described later) and a lower end portion of the second rail portion 74 (a second lower rail portion 74b described later). FIG. 8 is a cross-sectional view taken along arrows VIII-VIII in FIG. 7, and FIG. 9 is a cross-sectional view taken along arrows IX-IX in FIG. 7.

[0058] 3 to 7, each second rail portion 74 fits into the first rail portion 45 of the segment 4 at the same position in the circumferential direction, and engages with it so as to be able to tow the segment 4 outward. In this embodiment, the second rail portion 74 engages with the first rail portion 45 so as to be able to tow the segment 4 outward with the underside (surfaces 74as, 74bs, surfaces facing upward in the axial direction and outward in the radial direction) of the horizontal bar portion of the T-shaped second rail portion 74 abutting against the underside (surfaces 45as, 45bs) of the horizontal bar portion of the T-shaped first rail portion 45, which is a T-shaped guide groove.

[0059] The inclination angle of the second rail portion 74 in this embodiment (angle α shown in FIG. 1) refers to the inclination angle of the lower surface of the horizontal bar portion of the T-shape of the second rail portion 74.

[0060] In this embodiment, the second rail portion 74 has a second upper rail portion 74a, which is an upper end region, and a second lower rail portion 74b, which is a lower end region. The second upper rail portion 74a and the second lower rail portion 74b may be an integrated rail or separate rails. This embodiment illustrates a case where the second upper rail portion 74a and the second lower rail portion 74b are separate rail portions. The second upper rail portion 74a may be formed linearly. The second lower rail portion 74b may also be formed linearly. The inclination angle of the second upper rail portion 74a is smaller than the inclination angle of the second lower rail portion 74b. FIG. 8 is a cross-sectional view of the second upper rail portion 74a. FIG. 9 is a cross-sectional view of the second lower rail portion 74b.

[0061] As shown in FIGS. 3 to 7, the length of the second upper rail portion 74a along the axial direction may be shorter than the length of the second lower rail portion 74b along the axial direction.

[0062] The inclination angle of the second upper rail portion 74a is preferably 3° or more and 15° or less. The inclination angle of the second lower rail portion 74b is preferably 10° or more and 30° or less. The inclination angle of the second upper rail portion 74a is preferably 3° or more and 15° or less smaller than the inclination angle of the second lower rail portion 74b.

[0063] As described above, in a state in which the outer ring 7 closes the tread molding portion 3 (see FIG. 3), the radial distance between the first rail portion 45 and the second rail portion 74 is smaller on the upper end side than on the other end side. In this embodiment, the radial distance between the first upper rail portion 45a and the second upper rail portion 74a is smaller (closer) than the radial distance between the first lower rail portion 45b and the second lower rail portion 74b. In other words, the gap between the first upper rail portion 45a and the second upper rail portion 74a is narrower than the gap between the first lower rail portion 45b and the second lower rail portion 74b.

[0064] The opening and closing operation of the mold 100 in association with the raising and lowering of the ring 7 will be described below.

[0065] 3, when the upper container 2 descends, the ring 7 descends accordingly, causing the ring inner inclined surface 73 to come into contact with the outer surface 44 of the holder 41, urging the outer surface 44 inward and moving the segment 4 to the closed position.

[0066] When the ring 7 is in the holding position, the ring 7 holds the segments 4 in the closed position with the ring inner inclined surface 73 abutting against the outer surface 44.

[0067] 4 to 7, when the ring 7 rises from the holding position, the ring 7 pulls the segments 4 outward or upward via the first rail portions 45. Specifically, this is as follows.

[0068] When the upper container 2 rises, the ring 7 rises accordingly. As a result, the first rail portion 45 slides downward and outward relative to the second rail portion 74.

[0069] As the first rail portion 45 slides downward relative to the second rail portion 74, the second rail portion 74 of the ring 7 pulls the first rail portion 45 of the segment 4 outward. As a result, as the first rail portion 45 slides downward relative to the second rail portion 74, the segment 4 is pulled outward by the ring 7 via the second rail portion 74 and the first rail portion 45. When the segment 4 opens, it moves away from the adjacent segment 4. In other words, as the ring 7 rises, the segments 4 spread outward in the radial direction, and the tread molding portion 3 opens in the radial direction.

[0070] As described above, in the mold 100, the radial distance between the first upper rail portion 45a and the second upper rail portion 74a is smaller than the radial distance between the first lower rail portion 45b and the second lower rail portion 74b. Therefore, when the ring 7 is raised, the first upper rail portion 45a and the second upper rail portion 74a first come into contact with each other, as shown in Fig. 4. As a result, the segments 4 open outward while sliding the first upper rail portion 45a along the second upper rail portion 74a, with the first upper rail portion 45a in contact with the second upper rail portion 74a.

[0071] Thereafter, as the ring 7 further rises, the second upper rail portion 74a comes out of the first rail portion 45 (see FIG. 5) and is no longer in contact (sliding contact) with the first upper rail portion 45a (see FIG. 6). As the second upper rail portion 74a comes out of the first rail portion 45, the second lower rail portion 74b comes into contact with the first lower rail portion 45b (see FIG. 5). As the ring 7 rises, the segment 4 continues to move outward while sliding the first lower rail portion 45b along the second lower rail portion 74b, until it is completely released from the mold (see FIG. 6). After the segment 4 is sufficiently separated from the tire 200 (see FIG. 7), the ring 7 may pull the segment 4 upward (not shown).

[0072] When the segment 4 opens outward while sliding the first upper rail portion 45a along the second upper rail portion 74a during release, the first upper rail portion 45a is located on the upper end side of the segment 4, and therefore the first upper rail portion 45a (i.e., the upper end portion of the segment 4) is pulled outward by the second upper rail portion 74a. As a result, the segment 4 opens outward with its upper end slightly tilted outward. If the segment 4 has a chamfered portion 4a, the segment 4 can tilt so that the chamfered portion 4a is aligned with the upper surface of the plate portion 10, making this tilting more likely to occur. By tilting the segment 4 in this way, the driving force required to drive the segment 4 during the initial stage of release of the tire 200 from the mold can be reduced.

[0073] As the ring 7 rises, the second lower rail portion 74b abuts against the first lower rail portion 45b (first rail portion 45) (see Figure 5), and then the second upper rail portion 74a comes out of the first rail portion 45 and no longer abuts against the first upper rail portion 45a (see Figure 6), and the segment 4 returns from a state in which its upper end is tilted outward to a state in which its upper end is not tilted outward.

[0074] Now, the length along the axial direction of the first upper rail portion 45a may be shorter than the length along the axial direction of the first lower rail portion 45b, and the length along the axial direction of the second upper rail portion 74a may be shorter than the length along the axial direction of the second lower rail portion 74b. Therefore, after the second lower rail portion 74b abuts against the first lower rail portion 45b (first rail portion 45) (see Figure 5), when the second upper rail portion 74a comes out of the first rail portion 45 and is no longer abutting against the first upper rail portion 45a (see Figure 6), the length along the axial direction of the first upper rail portion 45a is made shorter than the length along the axial direction of the first lower rail portion 45b so that the second lower rail portion 74b is positioned lower than the center of the segment 4 (first rail portion 45) in the axial direction.Furthermore, by making the length along the axial direction of the second upper rail portion 74a shorter than the length along the axial direction of the second lower rail portion 74b, the upper end of the segment 4 can be made to tilt inward when the second upper rail portion 74a comes out of the first rail portion 45 and is no longer abutting against the first upper rail portion 45a.

[0075] The inclination angle of the first upper rail portion 45a is smaller than the inclination angle of the first lower rail portion 45b. The inclination angle of the second upper rail portion 74a is smaller than the inclination angle of the second lower rail portion 74b. Therefore, when the segments 4 open outward while sliding the first upper rail portion 45a along the second upper rail portion 74a, i.e., in the early stages of demolding of the tire 200, the speed at which the segments 4 move outward is smaller than the speed at which the segments 4 open outward while sliding the first lower rail portion 45b along the second lower rail portion 74b, i.e., after the early stages of demolding of the tire 200. This reduces the driving force required to drive the segments 4 in the early stages of demolding of the tire 200. This reduction also prevents shortening of the sipe life and avoids damage to the tread.

[0076] In the period after the initial stage of releasing the tire 200 from the mold, the speed at which the segments 4 move outward becomes faster than in the initial stage of releasing the tire 200, so the process time for molding the tire 200 can also be shortened.

[0077] (Description of Modifications) In the above embodiment, the second rail portion 74 has a T-shaped cross section along its extension direction, including a second upper rail portion 74a, which is an upper end region, and a second lower rail portion 74b, which is a lower end region. The second upper rail portion 74a and the second lower rail portion 74b are separate rail portions. The inclination angle of the second rail portion 74 refers to the inclination angle of the lower surface of the horizontal bar portion of the T-shaped second rail portion 74. However, the lower surface of the horizontal bar portion of the T-shaped second rail portion 74a or the second lower rail portion 74b does not necessarily need to be flat, and the inclination angle does not necessarily need to be specified. In the mold 200, it is sufficient that the inclination angle of the upper end region of at least one of the first rail portion 45 and the second rail portion 74 toward the radial inward direction is smaller than the inclination angle of the lower end region. For example, as shown in FIG. 10, the horizontal bar portion of the T-shape in the second upper rail portion 74a may be a pin 75, which is a rod-shaped member extending along the circumferential direction or a tangential direction thereof.

[0078] In this way, it is possible to provide a tire mold that can slow down the opening speed of the segments when releasing the tight contact between the mold surface and the tread.

[0079] It should be noted that the embodiments disclosed in this specification are merely examples, and the present invention is not limited to these embodiments, and can be modified as appropriate within the scope of the purpose of the present invention. [Industrial Applicability]

[0080] The present invention is applicable to tire molding molds. [Explanation of symbols]

[0081] 1: Lower container 10: Board part 100: Mold (tire mold) 11: Lower sidewall molding part 2: Upper container 20: Board part 200: Tire 21: Upper sidewall molding part 3: Tread molding section 4: Segment 4a: Chamfered part 40: Mold section 41: Holder 42: Container 44:Outer surface 45: First rail section 45a: First upper rail section 45as :face 45b: First lower rail section 45bs:face 7: Ring (outer ring) 72: Inner circumference 73: Inner inclined surface of ring 74: Second rail section 74a: Second upper rail section 74as :face 74b: Second lower rail section 74bs:face 75: Pin G: Axial center α :Angle β :Angle

Claims

1. a circular tread molding section having a mold section for forming a tire tread and divided into a plurality of segments arranged in a circumferential direction; an annular outer ring that is disposed radially outside the tread molding portion and moves along the axial direction of the tread molding portion to move the segments in the radial direction, thereby opening and closing the tread molding portion in the radial direction, The segment is and disposed radially outward of the mold portion, a first rail portion on an outer surface in the radial direction, the first rail portion engaging with the outer ring, extending along the axial direction and inclined inward in the radial direction; The outer ring is The axis of the tire overlaps with the axis of the tread molding portion, a second rail portion on an inner surface thereof, the second rail portion engaging with the first rail portion of each of the segments and extending along the first rail portion; When the outer ring closes the tread molding portion, the radial distance between the first rail portion and the second rail portion is such that the distance on one end side in the axial direction is smaller than the distance on the other end side, A tire molding mold, wherein the radially inward inclination angle of at least one of the first rail portion and the second rail portion is smaller in the region on the one end side than in the region on the other end side.

2. The first rail portion is a first upper rail portion which is an area on the one end side; a first lower rail portion which is the region on the other end side, The tire mold according to claim 1 , wherein the inclination angle of the first upper rail portion is smaller than the inclination angle of the first lower rail portion.

3. The second rail portion is a second upper rail portion which is an area on the one end side; a second lower rail portion which is the region on the other end side, The tire mold according to claim 1 , wherein the inclination angle of the second upper rail portion is smaller than the inclination angle of the second lower rail portion.

4. The second rail portion is a second upper rail portion which is an area on the one end side; a second lower rail portion which is the region on the other end side, The tire mold according to claim 2 , wherein the inclination angle of the second upper rail portion is smaller than the inclination angle of the second lower rail portion.

5. The second rail portion is a second upper rail portion which is an area on the one end side; a second lower rail portion which is the region on the other end side, 3. The tire mold according to claim 2, wherein the second upper rail portion is a rod-shaped member extending along the circumferential direction of the tread molding portion or along a tangential direction to the circumferential direction.

6. The tire mold according to claim 1 , wherein a length of the region on the one end side in the axial direction is shorter than a length of the region on the other end side.

7. The tire mold according to claim 1 , wherein the end portion of the segment on the one end side is inclined outward in the radial direction when the segment is opened.

8. 6. The tire mold according to claim 1, wherein a lower surface portion of the radially outer region at the lower end of the segment is located closer to one end in the axial direction than a lower surface portion of the radially inner region.

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