Tire molding mold

Abstract

Provided is a tire molding mold capable of reducing the driving force required for driving segments in the initial stage of demolding of a tire. The tire molding mold is provided with: a ring-shaped tread molding part which has a mold part and a holder for supporting the mold part, and is divided into a plurality of segments arranged in a circumferential direction; and an outer ring which is disposed on the outer side in the radial direction of the ring of the tread molding part, moves along the axial direction of the ring of the tread molding part to move the segments in the radial direction thereof to open and close the tread molding part in the radial direction thereof. The segments have an inclination mechanism which allows inclination of the mold part with respect to a tread when the tread molding part is opened toward the outer side in the radial direction. The inclination mechanism has an elastic member which urges the mold part toward the holder. The mold part is disposed on the inner side in the radial direction relative to the holder, and is supported by the holder via the inclination mechanism.

Description

Tire molding mold

[0001] The present disclosure relates to tire molds.

[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, 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 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. Furthermore, there is a problem that a large driving force is 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 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.

[0006] JP 2000-326332 A JP 2000-334740 A JP 2009-149079 A JP 2023-68580 A

[0007] However, in the prior art such as that 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 achieve an optimal inclination state in response to, for example, the type of tire, individual differences, or changes in the tire condition 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 stages of tire release. Therefore, there remains a need for a tire molding mold that can reduce the driving force required to drive the segments in the early stages of tire release.

[0008] The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide a tire molding mold that can reduce the driving force required to drive the segments in the early stages of tire demolding.

[0009] In order to achieve the above object, the tire molding mold according to the present disclosure comprises: an annular tread molding portion having a mold portion that forms the tread of a tire and a holder that supports the mold portion, the tread molding portion being divided into a plurality of segments that are arranged in the circumferential direction; and an annular outer ring that is arranged 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, wherein the segments have a tilting mechanism that allows the mold portion to tilt relative to the tread when the tread molding portion is opened radially outward, and the tilting mechanism has an elastic member that biases the mold portion toward the holder, and the mold portion is arranged radially inward of the holder and is supported by the holder via the tilting mechanism.

[0010] In the tire mold according to the present disclosure, the segment may have two or more of the tilting mechanisms.

[0011] In the tire mold according to the present disclosure, each of the tilting mechanisms may support a different position of the mold section.

[0012] In the tire mold according to the present disclosure, each of the tilting mechanisms may have elastic members with different elastic forces.

[0013] In the tire mold according to the present disclosure, the tilting 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 mold according to the present disclosure, the tilting mechanism may have a restricting mechanism that restricts the amount of deformation of the elastic member.

[0015] According to the present disclosure, the driving force required to drive the segments in the early stage of tire demolding can be reduced.

[0016] FIG. 1 is a cross-sectional view of a tire mold according to this embodiment, as seen from the front. FIG. 1 is a cross-sectional view of a tread molding portion, as seen from above. FIG. 2 is a cross-sectional view of a segment, as seen from the circumferential direction. FIG. 3 is a cross-sectional view of a main part of a tire mold in a closed state, as seen from the front. FIG. 4 is a cross-sectional view of a main part of a tire mold in a state where it is starting to open, as seen from the front. FIG. 5 is a cross-sectional view of a main part of a tire mold in an open state, as seen from the front. FIG. 6 is a cross-sectional view of a main part of a tire mold suspended from an outer ring, as seen from the outside. FIG. 7 is a side view of a segment, as seen from the inside. FIG. 8 is an explanatory diagram of a tilting mechanism of Modified Example 1. FIG. 9 is an explanatory diagram of a tilting mechanism of Modified Example 1. FIG. 10 is an explanatory diagram of a tilting mechanism of Modified Example 2. FIG. 11 is an explanatory diagram of a segment of Modified Example 3.

[0017] A tire mold according to an embodiment of the present disclosure will be described with reference to the drawings.

[0018] 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.

[0019] (Overview) The mold 100 is used to manufacture a tire 200 by molding a green tire made mainly of unvulcanized (before vulcanization) synthetic rubber into a predetermined shape while vulcanizing the green tire.

[0020] The mold 100 includes a mold section 40 that forms the tread of the tire 200 and a holder 41 that supports the mold section 40, an annular tread molding section 3 that is divided into a plurality of segments 4 arranged in the circumferential direction, and an outer ring 7 that is disposed 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 in the radial direction, thereby opening and closing the tread molding section 3 in the radial direction. The segments 4 have a tilting mechanism 5 that allows the mold section 40 to tilt relative to the tread when the tread molding section 3 is opened radially outward. The tilting mechanism 5 has an elastic member 6 that biases the mold section 40 toward the holder 41, and the mold section 40 is disposed radially inward of 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 early stages of demolding 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 radially 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 early stages of demolding.

[0022] (Detailed Description) The mold 100 will be described in detail below.

[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 will be referred to as the axial direction. The circumferential direction of the tread molding portion 3 and the same direction will be simply referred to as the circumferential direction. The radial direction 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 will sometimes be simply referred to as the outer side, and the inner side in the radial direction will sometimes 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 top view refers to a 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 underside of the plate portion 20. A ring 7 is suspended from the upper container 2 and supported by the ring 7. 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.

[0027] 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.

[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] 2 shows a cross-sectional plan view (top view) of the tread molding portion 3. As shown in FIG. 2, the tread molding 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] Each 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 circumferentially adjacent segment 4, 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.

[0032] Fig. 3 shows a cross-sectional view of the central portion of the segment 4 in the circumferential direction, as viewed along the circumferential direction. Figs. 4 to 7 show cross-sectional views of the main parts of the die 100, as viewed along 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] Figure 4 shows the segments 4 in the closed position, and Figures 5 to 7 show the segments 4 in the open position. A ring 7 is disposed on the outer side and above the tread molding portion 3. The ring 7 engages with each of the segments 4. The ring 7 moves the segments 4 between the closed position (see Figure 4) and the open position (see Figures 5 to 7). The ring 7 is freely movable between a holding position (see Figure 4) in which the segments 4 are held in the closed position, and a release position (see Figures 5 to 7) in which the segments 4 are in the open position. Note that Figure 5 shows a cross section of the mold 100 when the segments 4 begin to open. Figures 5 to 7 show the process of the segments 4 opening 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 where the ring 7 is lowest. The release position is the 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.

[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 tilt relative to the tread of the tire 200 when the tread molding section 3 is opened outward.

[0036] 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. In the open position, the segment 4 may be spaced apart 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 formed in any shape to match the desired tread shape or sipe shape. The circumferential ends of the mold section 40 are shaped to conform to the ends of the adjacent mold sections 40. When no inward external force is applied to the mold section 40, the mold section 40 is positioned adjacent to the inside of the holder 41 in a position where 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 part for positioning the mold part 40 relative to the holder 41. In this embodiment, as this positioning part, a recess 48 is formed on the outer surface of the mold part 40, into which a protrusion 49 formed on the inner surface of the holder 41 fits.

[0039] 4 to 7, the mold section 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 surface 44 of the holder 41 is an inclined surface in which the upper end of the holder 41 is positioned more inward than the lower end. The outer 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 surface 44, extending linearly in the vertical direction from the lower end to the upper end of the outer surface 44. The guide groove 45 has a so-called T-slot (dovetail) shape, in which the circumferential width of the opening at the top of the groove (the opening along the vertical direction formed on the outer surface 44) is smaller than the circumferential width of the bottom portion (inner portion) 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 part of the mold part 40 and whose outer end is urged 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 through-hole 62 may have a circular or elliptical shape. If the through-hole 62 has an elliptical shape (see FIG. 8), the pin member 65 can easily swing along the major axis of the elliptical shape.

[0045] The through-hole 62 may be formed with a step 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 at the portion outer than the step 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 of the elastic member 6 is supported by the step 62a via a washer 67, which will be described later, and biases the pin member 65 outward.

[0046] In this embodiment, the inner end of the elastic member 6 is 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 outer surface of the washer 67 supports the inner end of the elastic member 6. A pin member 65 is inserted through the washer 67. The outer diameter of the washer 67 is larger than the diameter of the portion of the through hole 62 that is inside 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 inner end of the pin member 65 is connected (for example, by threaded connection) to the outer part 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. In other words, 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 members 65 are swingable. Furthermore, the elastic force of the elastic members 6 allows the pin members 65 to swing. 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 members 6, and the mold section 40 is 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 reducing the driving force required to drive the segments 4 in the early stage of demolding 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 arranged 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 is permitted during demolding, 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 Figures 8 and 9, an example is shown in which the segment 4 has tilt mechanisms 51 to 54 as the tilt mechanism 5. In the example shown in Figures 8 and 9, the tilt mechanism 52 is arranged higher than the tilt mechanism 51. The tilt mechanism 53 is arranged 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 arranged 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 arrangement, but share the same basic shape. In the following, the tilt mechanisms 51 to 54 will be collectively referred to simply as the tilt mechanism 5.

[0052] If the segment 4 has two or more tilting mechanisms 5, each tilting mechanism 5 may have an elastic member 6 with a different elastic force (spring constant). This makes it possible to differentiate the ease of swing between a portion of the mold section 40 supported by one tilting mechanism 5 and a portion of the mold section 40 supported by another tilting 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 that is supported by one tilting mechanism 5 having an elastic member 6 with a large elastic force is less likely to separate from the holder 41 than a portion that is supported by the other tilting 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 that is supported by the other tilting mechanism 5 is relatively farther away from the holder 41 than the portion of the mold section 40 that is supported by one tilting 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 the outer surface 44 or guide groove 45 of the holder 41, which is the outer portion of the segment 4.

[0055] 4 to 7, the ring 7 has an inner peripheral portion 72 on which is formed an inner ring inclined surface 73 that faces inward and slopes so that the diameter gradually decreases upward. The inner ring inclined surface 73 faces inward, is linearly inclined with respect to the axial direction, and is an arc-shaped surface that follows 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 arranged on the inner peripheral portion 72 of the ring along the vertical direction and along the inner inclined surface 73 of the ring.

[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 extension 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 abut against the ring inner inclined surface 73 and extend along the ring inner inclined surface 73 from the lower end to the upper end.

[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, the guide portion 74 engages with the guide groove 45 so as to be able to pull the segment 4 outward with the underside of the horizontal bar portion of the T-shaped guide portion 74 abutting against the underside of the horizontal bar portion of the T-shaped guide groove 45.

[0060] The operation of the ring 7 and the segments 4 is as follows: When the upper container 2 is lowered, the ring 7 is lowered 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).

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

[0064] As the guide grooves 45 slide downward relative to the guide portions 74, the guide portions 74 of the ring 7 pull the guide grooves 45 of the segments 4 outward. As a result, as the guide grooves 45 slide downward relative to the guide portions 74, the segments 4 are pulled outward by the ring 7 via the guide portions 74 and the guide grooves 45. When the segments 4 are opened, they are separated from the adjacent segments 4. In other words, as the ring 7 rises, the segments 4 spread radially in the radial direction, and the tread molding portion 3 opens radially.

[0065] When the segments 4 are pulled outward by the ring 7 and move, the resistance when the mold section 40 peels 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 section 40 corresponding to the design surface pattern (tread pattern) of the tire 200 come out of this pattern act on the mold section 40 as a reaction force to the pulling. This reaction force acts on the mold section 40 as an inward external force. Due to this reaction force, the mold section 40 is pulled inward and becomes tiltable. In the following description, the time when the mold section 40 peels off from the tread of the tire 200 and the time when the molds of the sipes on the design surface of the mold section 40 come out of the sipes in the tread of the tire 200 may be collectively referred to simply as "during 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 of the smallest demolding resistance and undercut resistance during demolding, allowing for demolding. This reduces the driving force required to drive the segments 4 in the initial stage of demolding of the tire 200.

[0067] This inclination causes the mold section 40 to move outward while the upper end thereof is inclined outward relative to the tire tread, i.e., the mold section 40 gradually separates (peels) from the tread from the top to the bottom, thereby reducing mold release resistance. For example, the maximum value of mold release resistance can be reduced. Also, undercut resistance, which occurs when the protrusions (sipes) of the segments corresponding to the tire design surface pattern (tread pattern) are removed from the pattern, can be reduced. For example, the maximum value of undercut resistance can be reduced. These factors reduce the driving force required to drive the segments 4 in the initial stage of demolding of the tire 200.

[0068] The direction of this inclination of the mold section 40 is not limited to either the vertical direction or the circumferential direction. For example, during demolding, if the weakest adhesion portion of the decorative surface of the mold section 40 and the tread of the tire 200 is demolded first, the portion of the mold section 40 that was demolded first will be inclined so as to be positioned relatively outward relative to the portion that has not yet been demolded. Figure 4 shows a case in which the upper end side of the mold section 40 is demolded first from the tread. Figure 4 also shows an example in which the upper end side of the mold section 40 that was demolded first from the tread is positioned outward relative to the lower end side of the mold section 40 that has not yet been demolded.

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

[0070] As shown in Figure 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 Figure 7 shows a state in which the ring 7 is further raised after the mold section 40 is completely released from the tread (see Figure 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 when the ring 7 descends again 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 way, the ring 7 moves the segments 4 between the closed position and the open position, radially opening and closing the tread molding portion 3. 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 tilts, reducing the driving force required to drive the segments 4 in the initial stage of release.

[0073] (Variation 1) In the above embodiment, the tilt mechanism 5 includes one elastic member 6. However, as shown in Figures 10 and 11, the tilt mechanism 5 may be modified to include two or more elastic members 6 with different elastic forces, with the elastic members 6 connected in series. Figures 10 and 11 show explanatory diagrams of a variation of such a tilt mechanism 5. Figures 10 and 11 show a variation 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 bolt head 65a side), and the elastic member 6b is disposed on the inside (the step portion 62a side). 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 inner diameter of the washer 66 is smaller than the diameter of the coil of the elastic member 6a, and the outer diameter is larger than the diameter of the coil of the elastic member 6a. The inner diameter of the washer 68 is smaller than the diameter of the coil of the elastic members 6a and 6b, and the outer diameter is larger than the diameter of the coil of the elastic members 6a and 6b. The inner diameter of the washer 67 is smaller than the diameter of the coil of the elastic member 6b, and the outer diameter is 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 portion of the through-hole 62 that is inside the step portion 62a.

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

[0079] In the tilting mechanism 5 having elastic members 6a and 6b with 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, a variation may be made in which a restriction mechanism that restricts the amount of deformation of the elastic member 6 is added to the tilt mechanism 5. Figures 12 and 13 are explanatory views of such a variation of the tilt mechanism 5. For example, the tilt mechanism 5 shown in Figures 12 and 13 has, as a restriction mechanism that restricts the amount of deformation of the elastic member 6, a step 62b that is arranged at a position outside the step 62a in the through hole 62, and a washer 66 that is arranged between the bolt head 65a and the elastic member 6.

[0081] The step 62b has a stepped structure in which the diameter of the portion inside the step 62b is narrower than the portion outside the step 62b in the through hole 62. The outer diameter of the washer 66 is larger than the diameter of the portion inside the step 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 62b.

[0082] 13, the tilting mechanism 5 having such a restricting mechanism restricts the deformation of the elastic member 6 to a range up to the point where the washer 66 abuts against the step portion 62b. This makes it possible to adjust the tilt state of the mold section 40 during mold release.

[0083] (Variation 3) In the above embodiment, the mold section 40 in the segment 4 may be divided in the vertical or circumferential direction. FIG. 14 is an explanatory diagram (side view of the segment as seen from the inside) of such a variation of the segment 4. FIG. 14 illustrates an example of a segment 4 in which the mold section 40 is divided in the vertical and circumferential directions 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 tilting mechanisms 51 to 54, respectively. The mold pieces 401 to 404 are allowed to tilt relative to the tread by the corresponding tilting mechanisms 51 to 54, respectively. In this mold section 40, the mold pieces 401 to 404 are individually tiltable, and therefore, during demolding, they individually tilt depending on the tread condition of the tire 200 (see FIG. 1 ) corresponding to the mold pieces 401 to 404. This further reduces the driving force required to drive the segment 4 during the initial stage of demolding of the tire 200.

[0084] In this way, it is possible to provide a tire mold that can reduce the driving force required to drive the segments in the early stage of tire release.

[0085] Other Embodiments (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 that the segment 4 has is not limited to four. For example, the number of tilt mechanisms 5 that the segment 4 has may be one, two, or three. The number of tilt mechanisms 5 that the segment 4 has 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, as long as no contradictions arise. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present disclosure are not limited to these and can be modified as appropriate within the scope of not departing from the purpose of the present disclosure.

[0088] The present disclosure is applicable to tire molding molds.

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

Claims

1. A tire molding mold comprising: a mold portion that forms a tire tread, and a holder that supports the mold portion, and an annular tread molding portion divided into a plurality of segments arranged in the circumferential direction; and an annular outer ring that is arranged 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, wherein the segments have a tilting mechanism that allows the mold portion to be tilted relative to the tread when the tread molding portion is opened radially outward, the tilting mechanism having an elastic member that biases the mold portion towards the holder, and the mold portion is arranged radially inward from the holder and supported by the holder via the tilting mechanism.

2. A tire molding mold as claimed in claim 1, wherein said segment has two or more of said tilting mechanisms.

3. A tire molding mold as claimed in claim 2, wherein each of said tilt mechanisms supports a different position of said mold section.

4. A tire molding die as claimed in claim 2 or 3, wherein each of said tilting mechanisms has said elastic members with different elastic forces.

5. A tire molding mold as described in any one of claims 1 to 3, wherein the tilting mechanism has two or more elastic members each having a different elastic force, and the elastic members are connected in series.

6. A tire molding die according to any one of claims 1 to 3, wherein the tilting mechanism has a restricting mechanism for restricting the amount of deformation of the elastic member.

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