Tire molding die

Abstract

To provide a tire molding die capable of reducing a driving force necessary to drive a segment in an initial tire release.SOLUTION: The tire molding die 100 includes a mold part 40, a holder 41 that supports the mold part 40, and a ring-shaped tread molding part 3 divided into multiple segments 4 arranged in the circumferential direction, and an outer ring 7 positioned on the outside in the radial direction of the ring of the tread molding part 3, and moves along the axial direction of the ring of the tread molding part 3 to open and close the tread molding part 3 radially by moving the segments 4 in that radial direction. The segments 4 have an inclination mechanism 5 that allows for the inclination of the mold part 40 with respect to the tread when the tread molding part 3 opens outward in the radial direction. The inclination mechanism 5 includes an elastic member 6 that biases the mold part 40 towards the holder 41, and the mold part 40 is positioned inside the holder 41 and supported by the holder 41 via the inclination mechanism 5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tire molding 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 a circular 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, resulting in the problem 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 pattern. 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. In addition, there was a problem that a large driving force was required to drive the segment due to undercut resistance when the segment protrusions corresponding to the pattern are removed from the tire's design surface pattern until the segment is demolded from the tire.

[0005] Patent Document 4 discloses a tire molding die 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 inclination of the segments to their original position after the tread molding portion is opened. It is said that this tire molding die can reduce the driving force required to drive the segments in the initial stage of tire demolding by tilting the segments radially outward when the tread molding portion is opened radially outward. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2000-326332 A [Patent Document 2] JP 2000-334740 A [Patent Document 3] JP 2009-149079 A [Patent Document 4] JP 2023-68580 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the prior art disclosed in Patent Document 4, the inclination of the segments including the mold is controlled in a standard manner, and it is not possible to obtain an optimal inclination state according to, for example, the type of tire, individual differences, or changes in the state of the tire due to fluctuations in the manufacturing environment, and it is not possible to sufficiently reduce the driving force required to drive the segments in the early stage of tire demolding. Therefore, there is still a need to provide a tire molding mold that can reduce the driving force required to drive the segments in the early stage of tire demolding.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a tire molding die that can reduce the driving force required to drive the segments in the initial stage of tire demolding. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a tire molding mold, A tread molding section having a ring-shaped mold section for forming a tread of a tire and a holder for supporting the mold section, the ring-shaped mold section being divided into a plurality of segments arranged in a circumferential direction; an annular outer ring that is disposed radially outside the ring of the tread molding portion and moves along the axial direction of the ring 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 has a tilting mechanism that allows the mold portion to be tilted relative to the tread when the tread molding portion is opened outward in the radial direction, the tilting mechanism has an elastic member that biases the mold part toward the holder, The mold portion is disposed radially inward of the holder and is supported by the holder via the tilting mechanism.

[0010] In the tire molding mold according to the present invention, The segment may have two or more of the tilt mechanisms.

[0011] In the tire molding mold according to the present invention, Each of the tilt mechanisms may support a different position of the mould section.

[0012] In the tire molding mold according to the present invention, Each of the tilt mechanisms may have the elastic members with different elastic forces.

[0013] In the tire molding mold according to the present invention, The tilt mechanism may have two or more elastic members each having a different elastic force, and the elastic members may be connected in series.

[0014] In the tire molding mold according to the present invention, The tilt mechanism may include a restricting mechanism that restricts an amount of deformation of the elastic member. Effect of the Invention

[0015] According to the present invention, it is possible to reduce the driving force required to drive the segments in the initial stage of tire demolding. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a cross-sectional view of the tire molding die according to the present embodiment as seen from the front. [Diagram 2] FIG. 2 is a cross-sectional view of a tread molding portion in a plan view. [Diagram 3] FIG. 4 is a cross-sectional view of a segment as viewed in the circumferential direction. [Figure 4] FIG. 2 is a cross-sectional front view of a main portion of a tire mold in a closed state. [Diagram 5] FIG. 2 is a cross-sectional front view of a main portion of a tire mold in a state in which the mold is beginning to open. [Figure 6] FIG. 2 is a cross-sectional front view of a main portion of a tire mold in an open state. [Figure 7] FIG. 2 is a cross-sectional front view of a main part of a tire molding die suspended from an outer ring. [Figure 8] FIG. 4 is a side view of the segment as seen from the outside. [Figure 9] FIG. 4 is a side view of the segment as seen from the inside. [Figure 10] 11 is an explanatory diagram of a tilting mechanism of the first modified example. FIG. [Figure 11] 11 is an explanatory diagram of a tilting mechanism of the first modified example. FIG. [Figure 12] 13 is an explanatory diagram of a tilting mechanism of the second modified example. FIG. [Figure 13] 13 is an explanatory diagram of a tilting mechanism of the second modified example. FIG. [Figure 14] FIG. 13 is an explanatory diagram of a segment of the third modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A tire molding die according to an embodiment of the present invention will be described with reference to the drawings.

[0018] First embodiment FIG. 1 shows a cross-sectional front view of a tire molding die 100 according to this embodiment (hereinafter, may be referred to as die 100).

[0019] (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 the green tire.

[0020] The mold 100 includes a mold part 40 for forming the tread of the tire 200, a holder 41 for supporting the mold part 40, an annular tread molding part 3 divided into a plurality of segments 4 arranged in the circumferential direction, and an outer ring 7 arranged radially outside the ring of the tread molding part 3 and moving along the axial direction of the ring of the tread molding part 3 to move the segments 4 in the radial direction, thereby opening and closing the tread molding part 3 in the radial direction. The segments 4 have a tilting mechanism 5 that allows the mold part 40 to tilt with respect to the tread when the tread molding part 3 is opened radially outward. The tilting mechanism 5 has an elastic member 6 that biases the mold part 40 toward the holder 41, and the mold part 40 is arranged radially inward from the holder 41 and is supported by the holder 41 via the tilting mechanism 5.

[0021] The mold 100 can reduce the driving force required to drive the segments 4 in the initial stage of release of the tire 200. In the mold 100, the tilting mechanism 5 allows the mold section 40 to be tilted relative to the tread, so the segments 4 open in the radial direction as the outer ring 7 moves, and the segments 4 tilt due to resistance when the mold section 40 is released from the tread surface of the tire 200, reducing the driving force required to drive the segments 4 in the initial stage of release.

[0022] (Detailed explanation) The mold 100 will now be described in detail.

[0023] 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.

[0024] Hereinafter, the direction along the axis G of the tread molding portion 3 is referred to as the axial direction. The circumferential direction of the tread molding portion 3 and the same direction are simply referred to as the circumferential direction. The radial direction of the tread molding portion 3 and the same direction are 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 viewed from the lower container 1 is referred to as the upper side, upward, or top, and the direction facing the lower container 1 as viewed from the upper container 2 is referred to as the lower side, downward, or bottom. In this embodiment, the top view refers to the viewpoint when looking down from above along the axial direction.

[0025] 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.

[0026] The upper container 2 has a plate portion 20 and an upper sidewall molding portion 21 fixed to the lower surface of the plate portion 20. The upper container 2 supports a ring 7 by suspending it. In this embodiment, the ring 7 is suspended from the upper container 2 with its upper end portion 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.

[0027] The lower sidewall molding portion 11 and the upper sidewall molding portion 21 are dies that form the side portions (sidewalls) of the tire 200. The lower sidewall molding portion 11 and the upper sidewall molding portion 21 are formed in annular shapes that are 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.

[0028] The tread molding section 3 is a unit including a mold for forming 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.

[0029] Fig. 2 shows a cross-sectional plan view (top view) of the tread mold portion 3. As shown in Fig. 2, the tread mold portion 3 is divided into a plurality of segments 4 arranged in the circumferential direction.

[0030] The tread mold 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 mold 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 mold portion 3. Hereinafter, the inner surface of the segments 4 may be referred to as the design surface of the segments 4.

[0031] The segment 4 is movable between a closed position (see FIG. 2) where the design surface of the segment 4 is continuous with the design surface of another segment 4 adjacent in the circumferential direction, and an open position where the design surface of the segment 4 is discontinuous with the design surface of the other 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, along the radial direction between the open position and the closed position.

[0032] Fig. 3 shows a cross-sectional view of the central portion of the segment 4 in the circumferential direction, as viewed in the circumferential direction. Figs. 4 to 7 show cross-sectional views of the main portion of the die 100 as viewed in the circumferential direction. Fig. 8 shows a side view of the segment 4 as viewed from the outside. Fig. 9 shows a side view of the segment 4 as viewed from the inside.

[0033] FIG. 4 shows the segment 4 in the closed position, and FIGS. 5 to 7 show the segment 4 in the open position. The ring 7 is disposed on the outer side and upper side of the tread molding section 3. The ring 7 engages with each of the segments 4. The ring 7 moves the segment 4 between the closed position (see FIG. 4) and the open position (see FIGS. 5 to 7). The ring 7 is movable between a holding position (see FIG. 4) in which the segment 4 is held in the closed position, and a release position (see FIGS. 5 to 7) in which the segment 4 is in the open position. FIG. 5 shows a cross section of the mold 100 when the segment 4 starts to open. FIGS. 5 to 7 show the process in which the segment 4 opens in this order.

[0034] 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 position at which the ring 7 is lowest. Also, the release position is a position at which 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.

[0035] As shown in Figures 4 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 tilting mechanism 5 that allows the mold section 40 to be tilted relative to the tread of the tire 200 when the tread molding section 3 is opened outward.

[0036] The segment 4 is disposed on the inner side 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. In the open position, the segment 4 may be separated from the upper surface of the plate portion 10 (see FIG. 7).

[0037] As shown in Figures 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 according to the desired shape of the tread or the shape of the sipes. The ends of the mold section 40 in the circumferential direction are shaped to conform to the ends of the adjacent mold section 40. When no inward external force is applied to the mold section 40, the mold section 40 is disposed adjacent to the inside of the holder 41 in a position in which the outer surface of the mold section 40 is aligned with the inner surface of the holder 41 (hereinafter referred to as the initial position) (see Figures 4, 6 and 7).

[0038] The outer surface of the mold part 40 may have a positioning portion for positioning the mold part 40 relative to the holder 41. In this embodiment, as the positioning portion, a recess 48 into which a protrusion 49 formed on the inner surface of the holder 41 fits is formed on the outer surface of the mold part 40.

[0039] 4 to 7, the mold portion 40 is supported by a holder 41 via a tilting mechanism 5. The tilting mechanism 5 will be described later.

[0040] As shown in Figs. 3 to 7, the outer side surface 44 of the holder 41 is an inclined surface in which the upper end side of the holder 41 is located more inward than the lower end side. The outer side surface 44 is an arc-shaped surface along the circumferential direction when viewed from above (see Fig. 2). A guide groove 45 (an example of a first rail portion) is formed on the outer side surface 44, which extends linearly along the up-down direction from the lower end to the upper end of the outer side surface 44. The guide groove 45 has a so-called T-slot (dovetail) shape in which the width in the circumferential direction of the opening of the upper surface of the groove (the opening along the up-down direction formed on the outer side surface 44) is smaller than the width in the circumferential direction of the bottom part (inner part) of the groove. As shown in Figs. 4 to 7, the guide groove 45 engages with the ring 7. The engagement between the guide groove 45 and the ring 7 will be described later.

[0041] As an example, the tilting mechanism 5 may include an elastic member 6 whose inner end is supported by the holder 41, a through hole 62 formed in the holder 41 along the radial direction, and a pin member 65 whose inner end is connected to the outer portion of the mold portion 40 and whose outer end is biased outward by the elastic member 6.

[0042] The elastic member 6 may be, for example, a coil spring. When the elastic member 6 is a coil spring, the elastic member 6 may be disposed such that the axial direction of the coil is aligned with the radial direction.

[0043] The diameter (inner diameter) of the through hole 62 is larger than the diameter of the pin member 65. This allows the pin member 65 to swing in the axial direction of the through hole 62 within the through hole 62.

[0044] The hole shape of the through hole 62 may be, for example, a circular shape or an elliptical shape. When the hole shape of the through hole 62 is, for example, an elliptical shape (see FIG. 8), the pin member 65 is easily able to swing along the major axis of the elliptical shape.

[0045] The through hole 62 may be formed with a step portion 62a having a stepped structure in which the diameter of the inner portion is narrower than that of the outer portion. The diameter of the through hole 62 in the portion outer than the step portion 62a is larger than the diameter (outer diameter) of the coil of the elastic member 6. In this embodiment, with at least a portion of the elastic member 6 inserted into the through hole 62, the inner end portion is supported by the step portion 62a via a washer 67 described later, and the pin member 65 is biased outward.

[0046] In this embodiment, the elastic member 6 has an inner end supported by the step portion 62a via a washer 67 whose inner diameter is smaller than the diameter of the coil of the elastic member 6 and whose outer diameter is larger than the diameter of the coil of the elastic member 6. That is, the inner surface of the washer 67 (the surface facing inward when inserted into the through hole 62) is supported by the step portion 62a, and the inner end of the elastic member 6 is supported by the outer surface of the washer 67. The pin member 65 is inserted through the washer 67. The outer diameter of the washer 67 is larger than the diameter of the part of the through hole 62 that is more inward than the step portion 62a.

[0047] The pin member 65 is, for example, a bolt having a bolt head 65a. The pin member 65 is inserted through the through hole 62. The pin member 65 is also inserted inside the coil of the elastic member 6, which is a coil spring. The pin member 65 has an inner end connected (for example, screw-connected) to the outer side of the mold part 40, and the inner surface of the bolt head 65a is biased outward by the elastic member 6. As a result, the mold part 40 is biased outward by the elastic member 6 via the pin member 65.

[0048] In this embodiment, the pin member 65 is biased against the inner surface of the bolt head 65a by the elastic member 6 via a washer 66 whose inner diameter is smaller than the diameter of the coil of the elastic member 6 and whose outer diameter is larger than the diameter of the coil of the elastic member 6. That is, the outer surface of the washer 66 is supported by the bolt head 65a, and the inner surface of the washer 66 is biased by the outer end of the elastic member 6. The pin member 65 is inserted through the washer 66.

[0049] As described above, the pin member 65 is swingable. Furthermore, the elastic member 6 allows the pin member 65 to swing by its elastic force. Therefore, when the mold section 40 is pulled inward relative to the holder 41, such as during demolding, at least a portion of the mold section 40 moves away from the holder 41 against the biasing force of the elastic member 6, and the mold section 40 becomes swingable, i.e., tiltable, relative to the holder 41 and the tread. In this way, the tilting mechanism 5 allows the mold section 40 to tilt relative to the holder 41 and the tread, thereby making it possible to reduce the driving force required to drive the segments 4 in the early stage of demolding of the tire 200.

[0050] The segment 4 may have one or more tilting mechanisms 5. When the segment 4 has two or more tilting mechanisms 5, the respective tilting mechanisms 5 may be disposed at different positions in the vertical or circumferential direction. That is, the tilting mechanisms 5 may support different positions of the mold section 40. When the segment 4 has two or more tilting mechanisms 5, tilting of the mold section 40 during demolding is permitted, while the posture of the mold section 40 relative to the holder 41 is stable at times other than demolding, making it easier to open and close the segment 4.

[0051] In this embodiment, as shown in Figs. 8 and 9, a case is illustrated in which the segment 4 has tilt mechanisms 51 to 54 as the tilt mechanism 5. In the example shown in Figs. 8 and 9, the tilt mechanism 52 is disposed above the tilt mechanism 51. The tilt mechanism 53 is disposed at the same position as the tilt mechanism 51 in the up-down direction, but at a different position in the circumferential direction. The tilt mechanism 54 is disposed at the same position as the tilt mechanism 52 in the up-down direction, and at the same position as the tilt mechanism 53 in the circumferential direction. The tilt mechanisms 51 to 54 have different radial lengths due to differences in their arrangements, but share a common basic shape. In the following, the tilt mechanisms 51 to 54 will be collectively described simply as the tilt mechanism 5.

[0052] When the segment 4 has two or more tilt mechanisms 5, each tilt mechanism 5 may have an elastic member 6 with a different elastic force (spring constant). This makes it possible to make the ease of swinging different between a portion of the mold section 40 supported by one tilt mechanism 5 and a portion supported by another tilt mechanism 5. In other words, it is possible to adjust the direction in which the mold section 40 is more likely to tilt.

[0053] For example, a portion of the mold section 40 supported by one tilt mechanism 5 having an elastic member 6 with a large elastic force is less likely to separate from the holder 41 than a portion supported by the other tilt mechanism 5 having a smaller elastic force than the elastic member 6. Therefore, the mold section 40 is tilted so that the portion of the mold section 40 supported by the other tilt mechanism 5 is relatively farther away from the holder 41 than the portion of the mold section 40 supported by one tilt mechanism 5.

[0054] 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 guide groove 45 of a holder 41 which is an outer portion of the segment 4.

[0055] 4 to 7, the ring 7 has an inner peripheral portion 72 on which a ring inner inclined surface 73 is formed, the ring inner inclined surface 73 facing inward and inclining so that the diameter gradually decreases toward the upper side. The ring inner inclined surface 73 is an arc-shaped surface that faces inward, inclines linearly with respect to the axial direction, and extends along the circumferential direction so that the upper end side is located more inward than the lower end side.

[0056] A rail-shaped guide portion 74 is disposed on the ring inner circumferential portion 72 along the vertical direction and along the ring inner inclined surface 73 .

[0057] The guide 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.

[0058] The guide portion 74 has a T-shaped cross section when viewed along the extending direction. In other words, the circumferential width of the guide portion 74 on the side away from the ring inner circumferential portion 72 is wider than the circumferential width on the side close to the ring inner circumferential portion 72. The guide portion 74 is disposed so as to extend from the lower end to the upper end of the ring inner circumferential portion 73 along the ring inner circumferential portion 73 in a state of abutting against the ring inner circumferential portion 73.

[0059] Each guide portion 74 fits into the guide groove 45 of the segment 4 at the same position in the circumferential direction, and engages with it so as to be able to pull the segment 4 outward. In this embodiment, with the underside of the T-shaped cross bar portion of the T-shaped guide portion 74 abutting against the underside of the T-shaped cross bar portion of the T-shaped guide groove 45, the guide portion 74 engages with the guide groove 45 so as to be able to pull the segment 4 outward.

[0060] The operation of the ring 7 and the segments 4 is as follows: When the upper container 2 descends, the ring 7 descends accordingly, causing the ring inner inclined surface 73 to abut against the outer surface 44 of the holder 41, urging the outer surface 44 inward toward the closed position, and moving the segments 4 inward.

[0061] When the ring 7 is in the holding position, the ring inner inclined surface 73 abuts against the outer surface 44 to hold the outer surface 44 in the closed position (see FIG. 4).

[0062] Furthermore, when the ring 7 rises from the holding position, the ring 7 pulls the segments 4 outward or upward via the guide grooves 45 on the outer surface 44 (see Figs. 5 and 6). Specific examples are as follows.

[0063] When the upper container 2 rises, the ring 7 rises accordingly. As a result, the guide groove 45 slides downward and outward relative to the guide portion 74, as shown in FIG.

[0064] As the guide groove 45 slides downward relative to the guide portion 74, the guide portion 74 of the ring 7 pulls the guide groove 45 of the segment 4 outward. As a result, as the guide groove 45 slides downward relative to the guide portion 74, the segment 4 is pulled outward by the ring 7 via the guide portion 74 and the guide groove 45 and moves. When the segment 4 is opened, it moves away from the adjacent segment 4. In other words, as the ring 7 rises, the segments 4 spread out radially along the radial direction, and the tread molding portion 3 opens in the radial direction.

[0065] When the segment 4 is pulled outward by the ring 7 and moves, the resistance when the mold part 40 is peeled off from the tread of the tire 200 (hereinafter referred to as mold release resistance) and the undercut resistance when the protrusions (sipes) of the mold part 40 corresponding to the design surface pattern (tread pattern) of the tire 200 come out of this pattern act on the mold part 40 as a reaction force to the pulling force. This reaction force acts on the mold part 40 as an inward external force. Due to this reaction force, the mold part 40 is pulled inward and can be tilted. In the following description, the time when the mold part 40 is peeled off from the tread of the tire 200 and the time when the mold of the sipes on the design surface of the mold part 40 comes out of the sipes of the tread of the tire 200 may be collectively referred to simply as the time of mold release.

[0066] Since the mold section 40 supported by the holder 41 via the tilting mechanism 5 can be tilted with respect to the tread of the tire 200, the mold section 40 naturally tilts in the direction in which the demolding resistance and undercut resistance are not the smallest during demolding, and thus is demolded. This makes it possible to reduce the driving force required to drive the segments 4 in the initial stage of demolding of the tire 200.

[0067] Due to this inclination, the mold section 40 moves outward while inclining the upper end side outward with respect to the tire tread, that is, while gradually releasing (peeling) from the tread from the top to the bottom of the mold section 40, so that the mold release resistance can be reduced. For example, the maximum value of the mold release resistance can be reduced. In addition, the undercut resistance occurring when the protrusions (sipes) of the segments corresponding to the tire design surface pattern (tread pattern) come out of this pattern can be reduced. For example, the maximum value of the undercut resistance can be reduced. As a result, the driving force required to drive the segments 4 in the initial stage of releasing the tire 200 from the mold can be reduced.

[0068] The direction of the inclination of the mold part 40 is not limited to either the vertical direction or the circumferential direction. For example, when the mold part 40 is released from the part of the intimate contact between the design surface of the mold part 40 and the tread of the tire 200, where the adhesion is weak, the mold part 40 is inclined so that the part that has been released first is relatively outwardly positioned relative to the part that has not yet been released. FIG. 4 shows a case where the upper end side of the mold part 40 is released first from the tread. FIG. 4 shows an example where the upper end side of the mold part 40 that has been released first from the tread is located outwardly of the lower end side of the mold part 40 that has not yet been released.

[0069] In this embodiment, the inclination state of the segments 4 when the tread molding portion 3 is opened in the radial direction automatically changes depending on the magnitude of the demolding resistance and the undercut resistance. Specifically, if the demolding resistance or the undercut resistance increases, the inclination of the segments 4 increases, and thus the demolding resistance and the undercut resistance are automatically adjusted to be smaller. Therefore, compared to the case where a predetermined inclination state is achieved at a predetermined timing or position, the driving force required to drive the segments 4 in the early stage of demolding of the tire 200 can be further reduced.

[0070] As shown in Fig. 6, after the mold section 40 is completely released from the tread, the mold section 40 returns to its initial position due to the biasing force of the elastic member 6 of the tilting mechanism 5. Note that Fig. 7 shows a state in which the ring 7 further rises after the mold section 40 is completely released from the tread (see Fig. 6), and the segment 4 is suspended by the ring 7.

[0071] As described above, after the mold section 40 is completely released from the tread, it returns to its initial position, so that when the ring 7 again descends toward the holding position, the mold section 40 is in its initial position and the segments 4 are again moved inward (see Figure 4).

[0072] In this manner, the ring 7 moves the segments 4 between the closed and open positions, radially opening and closing the tread molding portion 3. Then, the segments 4 are pulled open in the radial direction as the ring 7 moves, and when the mold portion 40 is released from the tread surface of the tire 200, the mold portion 40 is tilted, so that the driving force required to drive the segments 4 in the initial stage of release is reduced.

[0073] (Variation 1) In the above embodiment, the tilt mechanism 5 includes one elastic member 6. However, as shown in Figs. 10 and 11, the tilt mechanism 5 may be modified to have two or more elastic members 6 with different elastic forces, and the elastic members 6 may be connected in series. Figs. 10 and 11 show explanatory diagrams of such modified tilt mechanism 5. Figs. 10 and 11 show a modified example in which an elastic member 6a and an elastic member 6b with a weaker elastic force than the elastic member 6a are connected in series.

[0074] In this modification, the elastic member 6a is disposed on the outside (the side of the bolt head 65a), and the elastic member 6b is disposed on the inside (the side of the step portion 62a). A washer 66 is disposed between the bolt head 65a and the elastic member 6a. The elastic member 6a biases the bolt head 65a outward via the washer 66.

[0075] A washer 68 is disposed between the elastic members 6a and 6b, and supports the elastic members 6a and 6b. The elastic member 6b biases the bolt head 65a outward via the washer 67 and the elastic member 6a.

[0076] A washer 67 is disposed between the elastic member 6b and the step portion 62a, and the elastic member 6b is supported by the step portion 62a via the washer 67.

[0077] The pin member 65 is inserted through the washers 66, 67, and 68. The washer 66 has an inner diameter smaller than the diameter of the coil of the elastic member 6a, and an outer diameter larger than the diameter of the coil of the elastic member 6. The washer 68 has an inner diameter smaller than the diameter of the coil of the elastic members 6a and 6b, and an outer diameter larger than the diameter of the coil of the elastic members 6a and 6b. The washer 67 has an inner diameter smaller than the diameter of the coil of the elastic member 6b, and an outer diameter larger than the diameter of the coil of the elastic member 6b. The outer diameter of the washer 67 is larger than the diameter of the part of the through hole 62 that is on the inside of the step portion 62a.

[0078] In the tilting mechanism 5 having the elastic members 6a, 6b with different elastic forces as described above, by adjusting the difference in the elastic forces of the elastic members 6a, 6b and the difference in the allowable deformation amount, it becomes possible to control the tilt state at the time of demolding, such as the timing of tilting the mold section 40, the direction of tilting, and the speed of tilting.

[0079] In the tilting mechanism 5 having the elastic members 6a, 6b of different elastic forces as described above, for example, as shown in Figure 11, during demolding, the elastic member 6b with the smaller elastic force is deformed first to tilt the mold section 40 by a predetermined amount in a predetermined direction, and then the elastic member 6a with the larger elastic force is deformed to further tilt the mold section 40 by a predetermined amount in a predetermined direction.

[0080] (Variation 2) In the above embodiment, the tilt mechanism 5 may be modified to include a restriction mechanism for restricting the amount of deformation of the elastic member 6. Fig. 12 and Fig. 13 show explanatory views of such modified tilt mechanism 5. For example, the tilt mechanism 5 shown in Fig. 12 and Fig. 13 has, as a restriction mechanism for restricting the amount of deformation of the elastic member 6, a step 62b disposed at a position outside the step 62a in the through hole 62, and a washer 66 disposed between the bolt head 65a and the elastic member 6.

[0081] The step portion 62b has a stepped structure in which the diameter of a portion inside the step portion 62b is narrower than the diameter of a portion outside the step portion 62b in the through hole 62. The outer diameter of the washer 66 is larger than the diameter of the portion inside the step portion 62b in the through hole 62. The outer ends of the bolt head 65a, the washer 66 and the elastic member 6 are located outside the step portion 62b.

[0082] In the tilt mechanism 5 having such a restricting mechanism, the deformation amount of the elastic member 6 is restricted to a range in which the washer 66 abuts against the step portion 62b, as shown in Fig. 13. This makes it possible to adjust the tilt state of the mold part 40 during demolding.

[0083] (Variation 3) In the above embodiment, the mold section 40 may be divided in the vertical direction or the circumferential direction in the segment 4. FIG. 14 shows an explanatory diagram (side view of the segment from the inside) of such a modified example of the segment 4. FIG. 14 shows an example of the segment 4 in which the mold section 40 is divided in the vertical direction and the circumferential direction to form four pieces (mold pieces 401 to 404). In the example shown in FIG. 14, the mold pieces 401 to 404 are supported by the holder 41 via the tilting mechanisms 51 to 54, respectively. The mold pieces 401 to 404 are allowed to tilt with respect to the tread by the corresponding tilting mechanisms 51 to 54, respectively. In such a mold section 40, the mold pieces 401 to 404 are individually tiltable, so that at the time of demolding, the mold pieces 401 to 404 are individually tilted according to the state of the tread of the tire 200 (see FIG. 1) corresponding to the mold pieces 401 to 404. This makes it possible to further reduce the driving force required to drive the segment 4 in the initial stage of demolding of the tire 200.

[0084] In this manner, it is possible to provide a tire molding die that can reduce the driving force required to drive the segments in the initial stage of tire demolding.

[0085] [Another embodiment] (1) In the above embodiment, the elastic member 6 is a coil spring, but the elastic member 6 is not limited to a coil spring. The elastic member 6 may be, for example, a rubber-like member.

[0086] (2) In the above embodiment, the segment 4 has four tilt mechanisms 5. However, the number of tilt mechanisms 5 possessed by the segment 4 is not limited to four. For example, the number of tilt mechanisms 5 possessed by the segment 4 may be one, two, or three. The number of tilt mechanisms 5 possessed by the segment 4 may be five or more.

[0087] In addition, the configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, provided no contradiction arises. Furthermore, the embodiments disclosed in this specification are illustrative, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0088] The present invention is applicable to tire molding dies. [Explanation of symbols]

[0089] 1: Lower container 10: Board part 100: Mold (tire mold) 11: Lower sidewall molding 2: Upper container 20: Board part 200: Tire 21: Upper sidewall molding 3: Tread molding section 4: Segment 40: Mold section 401: Mold piece 402: Mold piece 403: Mold piece 404: Mold piece 41: Holder 44:Outer surface 45: Guide groove 48: Recess 49: Convex 5:Tilt mechanism 51:Tilt mechanism 52:Tilt mechanism 53:Tilt mechanism 54:Tilt mechanism 6: Elastic material 62: Through hole 62a: Stepped section 62b: Step (regulating mechanism) 65: Pin member 65a: Bolt head 66: Washer 67: Washer 68: Washer 6a: Elastic member 6b: Elastic member 7: Ring (outer ring) 72: Inner circumference of ring 73: Ring inner inclined surface 74: Guide section G: Axial center

Claims

1. A tread molding section having a ring-shaped mold section for forming a tread of a tire and a holder for supporting the mold section, the ring-shaped mold section being divided into a plurality of segments arranged in a circumferential direction; an annular outer ring that is disposed radially outside the ring of the tread molding portion and moves along the axial direction of the ring 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 has a tilting mechanism that allows the mold portion to be tilted relative to the tread when the tread molding portion is opened outward in the radial direction, the tilting mechanism has an elastic member that biases the mold part toward the holder, The mold portion is disposed on the inner side of the holder and is supported by the holder via the tilt mechanism.

2. The tire mold according to claim 1 , wherein the segment has two or more of the tilt mechanisms.

3. 3. The tire mold of claim 2, wherein each of the tilt mechanisms supports a different position of the mold section.

4. 4. The tire molding die according to claim 2, wherein each of the tilting mechanisms has an elastic member with a different elastic force.

5. 4. The tire mold according to claim 1, wherein the tilt mechanism has two or more elastic members each having a different elastic force, the elastic members being connected in series.

6. The tire mold according to claim 1 , wherein the tilt mechanism has a restriction mechanism that restricts a deformation amount of the elastic member.

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