WO2024122115A1

WO2024122115A1 - Mold for tire molding

Info

Publication number: WO2024122115A1
Application number: PCT/JP2023/030210
Authority: WO
Inventors: 泰之石原
Original assignee: 株式会社ブリヂストン
Priority date: 2022-12-06
Filing date: 2023-08-22
Publication date: 2024-06-13
Also published as: JP2024081484A

Abstract

Provided is a mold for tire molding that has a subdivided opening/closing mold structure suited for precision tire molding. The mold for tire molding comprises: an annular tread molding section divided into a plurality of segment pieces aligned in a circumferential direction; and an outer ring that is disposed above the tread molding section in the axial direction and moves along the axial direction of the tread molding section to open and close the tread molding section in the radial direction thereof. The outer ring engages with each of the segment pieces, and the segment pieces open and close in the radial direction in association with movement of the outer ring, each moving toward and away from adjacent segment pieces.

Description

Tire molding mold

This disclosure relates to a tire molding mold.

Many tire molding dies have an opening and closing mechanism that is divided into 7 to 13 divided dies (segments) in the circumferential direction. Some tire molding dies have a finely divided opening and closing die structure, where the design surface within each segment is further divided into finely divided pieces.

The advantages of increasing the number of divisions of the mold by further dividing the segments into pieces and opening and closing those pieces in the radial direction include making it easier to make the flow of rubber on the raw tire axially symmetrical and minimized during vulcanization when the mold is pressed against the raw tire and pressure and heat are applied, reducing demolding resistance, and improving tire quality. One example of reducing demolding resistance is minimizing undercuts formed by pattern parts such as the bones and sipes of the mold in the tire demolding direction when the tire is demolded. One example of improving tire quality is minimizing undercut removal resistance and the strain energy applied to the tire during demolding, thereby minimizing permanent deformation and residual strain of the rubber caused by demolding of complex patterns and improving the initial quality of the tire.

In recent years, tire groove patterns have become more complex. This has resulted in a tendency for the resistance to demolding to increase when a tire is demolded from a tire molding mold. This has created a demand for reducing the resistance to demolding and for molds with a finely divided opening and closing mold structure to be adopted.

An example of a mold with a finely divided open-close mold structure is a tire molding mold in which all of the pieces are configured to open and close in the radial direction in order to reduce demolding resistance (see, for example, Patent Document 1).

Patent Document 1 describes a tire molding die in which the die for molding the tire tread is composed of segments divided in the tire circumferential direction. In this tire molding die, the segments have multiple pieces divided in the tire circumferential direction. In this segment, only one of the pieces of the segment is fixed, and all other pieces are movable in the tire circumferential direction.

JP 2006-21357 A

However, with conventional molds that have a finely divided opening and closing mold structure, it was sometimes impossible to control the movement of each piece, and they were not sufficient for more precise tire molding.

This disclosure was made in consideration of this situation, and its purpose is to provide a tire molding mold with a finely divided open/close mold structure suitable for precision tire molding.

In order to achieve the above object, the tire molding mold according to the present disclosure comprises:
a circular tread molding portion divided into a plurality of segment pieces arranged in a circumferential direction;
an outer ring that is disposed axially above the tread molded portion and moves along the axial direction of the tread molded portion to open and close the tread molded portion in a radial direction;
the outer ring is engaged with each of the segment pieces;
The segment pieces are opened and closed in the radial direction in association with the movement of the outer ring, and are spaced apart from the adjacent segment pieces.

This disclosure makes it possible to provide a tire molding mold with a finely divided open/close mold structure suitable for precision tire molding.

FIG. 1 is a cross-sectional view of a tire molding mold according to a first embodiment as seen from the front. FIG. 2 is a cross-sectional view in plan view of a tread molding portion of the tire molding die of the first embodiment. FIG. 2 is a view of a portion of the tire molding die of the first embodiment in the circumferential direction as viewed from the inside. FIG. 2 is a view of a portion of the tire molding die of the first embodiment in the circumferential direction as viewed from the outside. FIG. 2 is a view of a portion of the tire molding die of the first embodiment viewed in the circumferential direction when the outer ring is in a retaining position. FIG. 2 is a view of a portion of the tire molding die of the first embodiment viewed in the circumferential direction when the outer ring is in a release position. FIG. 2 is a diagram showing a state in which a tread molding portion of the tire molding die according to the first embodiment is raised together with an upper container. FIG. 2 is a view showing a part in the circumferential direction of a tire molding die according to Modification 1 of the first embodiment, as viewed from the outside. FIG. 11 is a view of a portion of a tire molding die according to Modification 1 of the first embodiment, viewed in the circumferential direction, when the outer ring is in a release position. FIG. 11 is a view of a portion of a tire molding die according to Modification 2 of the first embodiment, viewed in the circumferential direction, when the outer ring is in a release position. FIG. 11 is a view of a portion of a tire molding die according to a second embodiment viewed in the circumferential direction when the outer ring is in a release position. FIG. 11 is a diagram showing a part of a cross section in a plan view of a tread molding portion and an outer ring of a tire molding die according to a second embodiment. FIG. 11 is a view of a portion of a tire molding die according to a second embodiment in a circumferential direction as viewed from the outside.

The tire molding mold according to the embodiment of the present disclosure will be described with reference to the drawings.

First Embodiment
FIG. 1 shows a cross-sectional front view of a tire molding die 100 (hereinafter, sometimes referred to as die 100) according to this embodiment.

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

The mold 100 includes an annular tread molding section 3 divided into a number of segment pieces 4 arranged in the circumferential direction, and an outer ring 7 that is disposed above the tread molding section 3 in the axial direction (direction along the axis G) and moves along the axial direction of the tread molding section 3 to open and close the tread molding section 3 in the radial direction. The outer ring 7 engages with each of the segment pieces 4. The segment pieces 4 open and close in the radial direction as the outer ring 7 moves, and are separated from adjacent segment pieces 4.

The mold 100 has a finely divided open/close mold structure. The mold 100 is suitable for precision tire molding.

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

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

Hereinafter, the direction along the axis G of the tread molding portion 3 will be referred to as the axial direction. Furthermore, the circumferential direction of the tread molding portion 3 and the same direction will be simply referred to as the circumferential direction. Furthermore, the radial direction of the tread molding portion 3 and the same direction will be simply referred to as the radial direction, with the outer side in the radial direction simply referred to as the outer side or the radial outer side, and the inner side simply referred to as the inner side or the radial inner side. In the axial direction, the direction facing the upper container 2 as viewed 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 viewed from the upper container 2 will be referred to as the lower side, downward, or bottom.

The lower container 1 is the seat of the mold 100, on which the upper container 2 and the tread molding section 3 are placed. 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.

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. 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 fixed to a position outside the upper sidewall molding portion 21. The upper container 2 can be raised and lowered relative to the lower container 1 along the axial direction.

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 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 form the side surfaces of the tire 200.

The tread molding section 3 is a unit that includes a mold that forms the tread surface of the tire 200. The inner surface of the tread molding section 3 is the 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.

FIG. 2 shows a cross-sectional view of the tread molding portion in a plan view. FIG. 3 shows a view of the mold 100 from the inside, illustrating a portion of the mold 100 in the circumferential direction. FIG. 4 shows a view of the mold 100 from the outside, illustrating a portion of the mold 100 in the circumferential direction. As shown in FIGS. 2 to 4, the tread molding portion 3 has a plurality of segment pieces 4 (hereinafter referred to as pieces 4) arranged in the circumferential direction.

The tread molding portion 3 may be divided into, for example, 30 to 90 pieces 4 in the circumferential direction. The pieces 4 are placed directly on the upper surface of the plate portion 10 of the lower container 1. In this embodiment, the tread molding portion 3 is divided into 45 pieces 4 each having the same circumferential length. The inner surface of the pieces 4 is the design surface of the tread molding portion 3. Hereinafter, the inner surface of the piece 4 may be referred to as the design surface of the segment piece 4.

Piece 4 can be moved between a closed position where the design surface of piece 4 is continuous with the design surface of an adjacent piece 4 in the circumferential direction, and an open position where the design surface of piece 4 is discontinuous with the design surface of an adjacent piece 4. In other words, the open position of piece 4 is a position outside the closed position of piece 4. Piece 4 can be moved, for example, in the radial direction between the open position and the closed position. Note that FIG. 3 shows the case where piece 4 is in the closed position, and FIG. 4 shows the case where piece 4 is in the open position.

Figures 5 and 6 show a circumferential portion of the mold 100 viewed along the circumferential direction. As shown in Figures 5 and 6, the ring 7 is disposed on the outer side and above the tread molding section 3, and is freely movable between a holding position (see Figure 5) in which the piece 4 of the tread molding section 3 is held in a closed position, and a release position (see Figure 6) in which the piece 4 is moved to an open position. In this embodiment, the ring 7 rises and falls as the upper container 2 rises and falls. In this embodiment, the specified position is the position at which the ring 7 is lowest. The release position is the position at which the ring 7 is higher than the specified position.

The ring 7 has an outer ring periphery 70 on which an outer ring inclined surface 71 faces outward and is inclined so that the diameter gradually decreases in the upward direction, and an inner ring periphery 75 on which an inner ring inclined surface 76 faces inward and is inclined so that the diameter gradually decreases in the upward direction.

The ring 7 engages with each of the pieces 4. The ring 7 moves the pieces 4 between the closed position and the open position. The operation of the ring 7 and the pieces 4 will be described later.

As shown in FIG. 6, the piece 4 has a split mold 40 whose inner surface is a design surface that forms the tread surface of the tire 200 (see FIG. 1), a holder 41 that supports the split mold 40, an arm portion 42 that is disposed at the lower end of the holder 41 and engages with the ring outer periphery 70, a biasing portion 46 that biases the lower end of the holder 41 outward, a biasing portion 47 that biases the upper end of the holder 41 outward, and a circumferential biasing portion 48 that biases the holder 41 in a direction away from the adjacent holder 41 in the circumferential direction.

As shown in FIG. 3, the split mold 40 has protrusions on its design surface that form grooves in the tire tread and protrusions that form sipes. The split mold 40 may be formed, for example, in a wavy shape that travels back and forth in the circumferential direction along the axial direction. The circumferential ends of the split mold 40 are shaped to follow the ends of the adjacent split molds.

As shown in FIG. 5 etc., the holder 41 is disposed adjacent to the outside of the split mold 40 and supports the outer part of the split mold 40. The inner part of the holder 41 is formed, for example, in a concave shape in which the axial inner part is recessed outward more than both axial ends, and the split mold 40 is supported by the holder 41 with its outer part fitted into the recess. The inner surfaces of the upper and lower ends of the holder 41 face the outer surfaces of the upper sidewall molding part 21 and the lower sidewall molding part 11, respectively. The holder 41 moves between an open position and a closed position while placed on the upper surface of the plate part 10 of the lower container 1.

The split mold 40 and holder 41 are positioned inside the ring 7.

The arm portion 42 may be composed of a base portion 42b extending outward from the lower end of the holder 41, a pillar portion 42c extending in a straight line further upward and inward from the end of the base portion 42b opposite the holder 41, and an abutment portion 42a formed on the end of the pillar portion 42c opposite the base portion 42b.

The arm portion 42 may be a part of the holder 41 or may be a separate body. Also, a part of the arm portion 42 (for example, the base portion 42b) may be a part of the holder 41. When the arm portion 42 and the holder 41 are separate bodies, they may be connected by screw fastening or the like.

The base 42b extends from the inside of the ring 7 (the lower end of the holder 41) toward the outside, and reaches the outside of the ring 7.

The arm portion 42 (pillar portion 42c) has an abutment portion 42a that protrudes inward at the end opposite the bottom end of the holder 41. The arm portion 42 has the abutment portion 42a that can engage with the outer periphery 70 of the ring.

The biasing portion 46 includes an elastic member such as a spring. The biasing portion 46 may be housed in a recess 43 formed, for example, at the lower end of the holder 41 from the inner surface of the holder 41 toward the outside. When the piece 4 is in a closed state, for example, the biasing portion 46 may have its inner end supported by the outer portion of the lower sidewall molding portion 11 to bias the holder 41 toward the outside.

The biasing portion 47 includes an elastic member such as a spring. The biasing portion 47 may be housed in a recess 44 formed, for example, in the upper end portion of the holder 41 from the inner surface of the holder 41 toward the outside. When the piece 4 is in a closed state, for example, the biasing portion 47 may bias the holder 41 toward the outside by supporting the inner end portion against the outer portion of the upper sidewall molding portion 21.

The circumferential biasing portion 48 includes an elastic member such as a spring. The circumferential biasing portion 48 may be housed in a recess 45 formed from one end face of the holder 41 in the circumferential direction toward the other end. When the pieces 4 are in a closed state, for example, the circumferential biasing portion 48 may have one end supported by one end face in the circumferential direction of an adjacent piece 4, and bias the

holders

41, 41 in a direction that separates the

pieces

4, 4 from each other.

The operation of piece 4 is as follows. When the upper container 2 descends, the ring 7 descends accordingly. This causes the ring inner inclined surface 76 to come into contact with the outer surface of the holder 41, moving piece 4 inward (for example, from the state in FIG. 6 to the state in FIG. 5).

When the upper container 2 rises, the ring 7 rises accordingly. As a result, the abutment portion 42a of the arm portion 42 abuts and engages with the ring outer inclined surface 71. When the ring 7 rises further with the abutment portion 42a abutting and engaging with the ring outer inclined surface 71, the abutment portion 42a moves downward and outward relative to the ring outer peripheral portion 70 along the ring outer inclined surface 71 as the ring 7 moves upward (for example, from the state in FIG. 5 to the state in FIG. 6). That is, the abutment portion 42a as the arm portion 42 is biased outward. Accordingly, the piece 4 moves outward and the tread molding portion 3 opens. When the tread molding portion 3 opens, the piece 4 moves away from the adjacent piece 4. In the following, the piece 4 moving outward and the tread molding portion 3 opening, and the piece 4 moving outward, may be described as the piece 4 opening, etc.

When the pieces 4 are opened, each piece 4 spreads out radially along the diameter direction. By dividing the tread molding portion 3 into a large number of pieces 4 (for example, 30 to 90 pieces in the circumferential direction), the demolding resistance applied to the tread surface of the tire 200 when the split mold 40 of the pieces 4 is released from the tread surface of the tire 200 can be reduced, and the power required to open the pieces 4 can be reduced. In addition, by reducing the demolding resistance applied to the tread surface of the tire 200, deformation of the tread surface of the tire 200 during demolding can be suppressed, and the initial performance of the tire 200 can be improved.

When the pieces 4 are opened, the circumferential biasing portion 48 biases the

holders

41, 41 in a direction that separates the

adjacent pieces

4, 4, thereby assisting in the separation of the

pieces

4, 4. This reduces the force required to open the pieces 4.

When piece 4 is opened, biasing

parts

46 and 47 bias holder 41 outward to assist in the outward movement of piece 4. This reduces the force required to open piece 4.

In this embodiment, a protrusion 72 extending outward may be formed on the lower end of the ring outer periphery 70. As a result, as shown in FIG. 7, when the upper container 2 rises and the abutment portion 42a moves downward and outward relative to the ring outer periphery 70 and reaches the lower end of the ring outer periphery 70, the abutment portion 42a becomes engaged with the protrusion 72. With the abutment portion 42a engaged with the protrusion 72, the tread molding portion 3, which is an assembly of pieces 4, can be raised together with the upper container 2.

The height at which the abutment portions 42a protrude inward may be different for each arm portion 42 of adjacent pieces 4. This allows the timing at which the split molds 40 of each piece 4 are released from the tire 200 to be staggered when the pieces 4 are opened. By staggering the timing at which the split molds 40 of each piece 4 are released from the tire 200, the maximum power required to open the pieces 4 can be reduced. In addition, by staggering the timing at which the split molds 40 of each piece 4 are released from the tire 200, the maximum release resistance applied to the tread surface of the tire 200 can be reduced, thereby suppressing deformation of the tread surface of the tire 200 during release and improving the initial performance of the tire 200.

(First Modification of the First Embodiment)
The piece 4 may be engaged with the lower container 1. For example, as shown in Figs. 8 and 9, an arm portion 42 may be engaged with the lower container 1.

For example, a cylindrical wall portion 19 may be provided that is formed in a ring shape along the outer periphery of the plate portion 10 of the lower container 1 and extends upward from the outer periphery of the plate portion 10.

The wall portion 19 has locking holes 13 that penetrate the wall portion 19 in the radial direction and are arranged to correspond to the movable range of each piece 4 in the circumferential direction. In other words, the locking holes 13 are formed along the radial direction. An arm portion 42 is inserted into each locking hole 13, thereby locking the piece 4 to the lower container 1.

In this case, the arm portion 42 may be composed of a base portion 42b extending outward from the lower end of the holder 41, a column portion 42c that is connected to the end of the base portion 42b opposite the holder 41 by screwing or the like and extends in a straight line upward, and an abutment portion 42a formed on the end of the column portion 42c opposite the base portion 42b.

The arm portion 42 can be attached to the holder 41 as follows. First, the base portion 42b is fixed to the holder 41, and then the end of the base portion 42b opposite the holder 41 is inserted into the locking hole 13 from the inside of the wall portion 19, so that the base portion 42b penetrates the wall portion 19. Then, from the outside of the wall portion 19, the pillar portion 42c is connected to the base portion 42b by screwing or the like.

(Modification 2 of the First Embodiment)
In the above embodiment, the biasing portion 46 that biases the lower end portion of the holder 41 outward is housed in the recess 43 that is formed from the inner surface of the holder 41 toward the outside at the lower end portion of the holder 41. However, the biasing portion 46 is not limited to being housed in the recess 43. The biasing portion 46 may be housed in the plate portion 10 of the lower container 1 as shown in FIG. 10 .

For example, a hole 12 extending inward from the outer circumferential surface of the plate portion 10 and having a closed inner end may be formed along the radial direction, and a spring or the like of the biasing portion 46 may be housed in this hole 12. In this case, the holder 41 may be biased by the biasing portion 46 via the piston 49.

The hole portion 12 may be provided with a first connecting hole 12a that is provided in the middle portion in the radial direction (the radial direction of the tread molding portion 3) and penetrates from the upper inner surface of the hole portion 12 to the upper surface of the plate portion 10, and a second connecting hole 12b that is provided in a position in the radial direction outside the first connecting hole 12a and penetrates from the upper inner surface of the hole portion 12 to the upper surface of the plate portion 10. The first connecting hole 12a and the second connecting hole 12b are formed in a rectangular or elliptical shape along the radial direction so that the radial width is longer than the circumferential width.

The piston 49 may have a rod-shaped portion 49a that is housed in the hole 12 and a branch portion 49b that extends upward from the inner end of the rod-shaped portion 49a.

A locking protrusion 49c that protrudes outward may be formed on the upper end of the branch portion 49b.

The branch portion 49b is engaged with the lower end of the holder 41 via the first connecting hole 12a. For example, a locking hole 41a for locking the upper end of the branch portion 49b may be formed in the lower end of the holder 41. The locking hole 41a may be an L-shaped hole that is recessed upward from the lower surface of the holder 41 and whose upper end (bottom of the hole) is further recessed outward. The branch portion 49b may lock the locking protrusion 49c into the L-shaped locking hole 41a. The biasing portion 46 biases the inner end of the rod-shaped portion 49a outward, thereby biasing the lower end of the holder 41 outward via the branch portion 49b and the locking hole 41a.

In this modified example, as an example, the base 42b is formed integrally with the holder 41. The base 42b is also formed with a through hole 41b that penetrates along the axial direction. The connecting pin 5 is inserted through the through hole 41b and the second connecting hole 12b, and the lower end of the connecting pin 5 is connected to the rod-shaped portion 49a via the through hole 41b and the second connecting hole 12b.

The lower end of the connecting pin 5 is connected to the rod-shaped portion 49a at a position outside the branch portion 49b. An enlarged diameter portion 51 is provided at the upper end of the connecting pin 5. A spring or the like of the biasing portion 52 is arranged between the enlarged diameter portion 51 and the base portion 42b, which biases the base portion 42b downward with the enlarged diameter portion 51 as a fulcrum. Figure 10 shows the case where the biasing portion 52 includes a torsion coil spring, and the connecting pin 5 is inserted into the coil of the biasing portion 52 and is inserted into the through hole 41b and the second connecting hole 12b to be connected to the rod-shaped portion 49a.

In this modified example, when the upper container 2 rises and the ring 7 rises from the specified position, the abutment portion 42a abuts against the ring outer inclined surface 71 and the piece 4 begins to move from the closed position to the open position, the piece 4 is configured to rotate around the locking hole 41a and the locking protrusion 49c as the rotation axis, and the upper end of the piece 4 is configured to open while tilting outward.

In other words, when the upper container 2 rises and the ring 7 rises from the specified position and the abutment portion 42a abuts against the ring outer inclined surface 71, the abutment portion 42a is biased outward. As a result, the holder 41 (piece 4), whose lower end is connected to the arm portion 42, rotates around the locking hole 41a and the locking protrusion 49c as the rotation axis, and opens while tilting the upper end outward.

In this way, the lower part of the piece 4 in the axial direction (axial direction of the tread molding portion 3) is journaled, and the upper part of the piece 4 is allowed to rotate (toward the outside in the radial direction) along the radial direction (radial direction of the tread molding portion 3), and the piece 4 opens while tilting, thereby reducing the demolding resistance when the split mold 40 is demolded from the tread surface of the tire 200 and reducing the power required to open the piece 4.

Second Embodiment
In the first embodiment, a case has been described in which the piece 4 has a split mold 40 whose inner surface is a design surface forming the tread surface of the tire 200 (see FIG. 1), a holder 41 that supports the split mold 40, and an arm portion 42 that is disposed at the lower end of the holder 41 and engages with the ring outer periphery 70 of the ring 7, as shown in FIG. 6, for example. Then, a case has been described in which, when the upper container 2 rises, the ring 7 rises accordingly, the arm portion 42 abuts against and engages with the ring outer inclined surface 71, and the arm portion 42 is biased outward, causing the piece 4 to move outward and open. However, the piece 4 is not limited to having the arm portion 42.

The second embodiment of the die 100 described below differs from the first embodiment in that, as shown in FIG. 11, the piece 4 has a first guide rail 6 instead of an arm portion 42, and the ring 7 has a second guide rail 8 on the ring inner circumference 75, but is otherwise similar to the first embodiment. The die 100 of this embodiment will be described below. In the following description, descriptions that overlap with the first embodiment will be omitted as appropriate.

The piece 4 has a first guide rail 6 that extends along the axial direction on the outer portion 41A of the holder 41, which is the outer periphery of the outer piece in the radial direction, and gradually slopes radially inward as it moves upward in the axial direction. In this embodiment, the outer portion 41A is formed with a piece outer inclined surface 41B that extends along the axial direction and gradually slopes radially inward as it moves upward in the axial direction.

The first guide rail 6 is arranged along the planar piece outer inclined surface 41B. The first guide rail 6 is fixed to the outer portion 41A by, for example, a male screw member 64. In FIG. 11, the female threaded portion of the outer portion 41A into which the male screw member 64 screws is shown as a screw hole 41H. The through hole of the first guide rail 6 through which the male screw member 64 is inserted is shown as an insertion hole 65. The male screw member 64 is arranged so that the head is located on the outer side in the radial direction, and the threaded portion is located on the inner side in the radial direction.

As shown in FIG. 12, the first guide rail 6 may be formed so that its cross-sectional shape when viewed along its extension direction is a T-shape. Note that FIG. 12 shows a cross-section of the tread molding portion 3 and ring 7 of the mold 100 in a plan view, and shows a portion of the cross-section of a portion including the circumferential biasing portion 48. The first guide rail 6 may be arranged so that the lower end 61 of the T-shape is located on the inside (the side close to the outer portion 41A) and the upper end side 62 of the T-shape (the horizontal bar part of the T-shape) is located on the outside.

As shown in FIG. 11, the ring 7 has a second guide rail 8 on the inner circumference 75 of the ring that extends along the axial direction and gradually slopes radially inward as it moves axially upward.

The second guide rail 8 may be formed, for example, as a groove-shaped space in the ring inner circumference 75. In this embodiment, the second guide rail 8 extends to the upper end of the ring 7 in the ring inner circumference 75.

In this embodiment, as an example, the second guide rail 8 is formed as a groove-like space 80 in the shape of the letter T when viewed in the direction of extension, as shown in FIG. 12.

The space 80 may be arranged so that the lower end 85 of the T-shape in its cross-sectional shape is located on the inside (the side closest to the piece 4) and opens onto the ring outer inclined surface 71 of the ring inner circumference 75, and the upper end 86 of the T-shape (the horizontal bar part of the T-shape) is located on the outside.

The first guide rail 6 fits into and engages with the groove of the second guide rail 8, and is guided along the second guide rail 8. The first guide rail 6 may fit into and engage with the groove of the second guide rail 8 with the upper end side 62 fitted into the upper end 86 of the second guide rail 8 and the lower end 61 fitted into the lower end 85 of the second guide rail 8.

When the ring 7 rises in conjunction with the rise of the upper container 2, the first guide rail 6 moves downward and outward relative to the second guide rail 8.

The pieces 4 are opened radially as the first guide rail 6 moves downward relative to the second guide rail 8. As in the first embodiment, the pieces 4 are separated from adjacent pieces 4 when opened.

Below, an example of the state and method of mounting the first guide rail 6 to the holder 41 is described.

As shown in FIG. 13, the ring 7 is formed with a through hole 77 for screw tightening that penetrates along the axis of the male screw member 64 and the screw hole 41H (see FIG. 11). The through hole 77 penetrates the ring 7 in the radial direction.

The through hole 77 is positioned so as to overlap with the second guide rail 8 when viewed in the radial direction.

The through hole 77 is positioned so that, when viewed in the radial direction, the ring 7 and the first guide rail 6 overlap, and the first guide rail 6 is guided by the second guide rail 8, the axis of the through hole 77 can overlap with the axis of the screw of the male screw member 64.

In this embodiment, the through hole 77 is exemplified as being such that, when the ring 7 is positioned at a specified position, the axis of the through hole 77 overlaps with the axis of the screw of the male screw member 64. FIG. 13 shows a case in which the first guide rail 6 is fixed to the holder 41 by three male screw members 64 arranged along the axial direction. Three through holes 77 are arranged in the ring 7 along the axial direction to correspond to these three male screw members 64. Note that, since the pieces 4 (holders 41) are arranged adjacent to each other in the circumferential direction, the through holes 77 may be arranged to correspond to the male screw members 64 of each holder 41.

The first guide rail 6 can be fixed to the holder 41 while engaged with the second guide rail 8 by the following procedure.

First, the ring 7 is removed from the upper container 2. Then, the piece 4 from which the first guide rail 6 has been removed is arranged along the inner peripheral surface of the ring 7. At this time, it is advisable to position the piece 4 so that the axis of the screw hole 41H of the piece 4 overlaps with the axis of the through hole 77 of the ring 7. Then, the first guide rail 6 is inserted from the upper end of the ring 7 into the groove of the second guide rail 8 and fitted in. Then, the first guide rail 6 is positioned along the second guide rail 8 so that the axis of the screw hole 41H, the axis of the insertion hole 65 of the first guide rail 6 (see FIG. 12), and the axis of the through hole 77 of the ring 7 overlap. Then, in this overlapping state, the male screw member 64 is inserted into the through hole 77 from the outside to the inside of the ring 7. The male screw member 64 that has been inserted into the through hole 77 is inserted into the insertion hole 65 as it is, and further screwed into the screw hole 41H. This allows the first guide rail 6 to be fixed to the holder 41 in a state of being engaged with the second guide rail 8. Then, the ring 7 can be attached to the upper container 2.

In this way, it is possible to provide a tire molding mold with a finely divided open/close mold structure suitable for precision tire molding.

[Another embodiment]
(1) In the above second embodiment, the first guide rail 6 is disposed along the planar piece outer inclined surface 41B of the outer portion 41A of the holder 41. However, if the piece outer inclined surface 41B is not planar, the first guide rail 6 does not necessarily need to be disposed along the piece outer inclined surface 41B. The first guide rail 6 only needs to be fixed to the outer portion 41A of the holder 41. For example, if the piece outer inclined surface 41B is a curved surface that is convex outward, the first guide rail 6 only needs to be fixed to the outer portion 41A at an angle that allows it to engage with the second guide rail 8.

(2) In the above embodiment, the piece 4 has a holder 41 and a split mold 40, and the split mold 40 is supported by the holder 41 with its outer portion fitted into the recess, i.e., the holder 41 is separate from the split mold 40. However, the holder 41 and the split mold 40 may be formed integrally.

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 contradictions arise. Furthermore, the embodiments disclosed in this specification are merely examples, and the embodiments of the present disclosure are not limited thereto, and can be modified as appropriate within the scope of the purpose of the present disclosure.

This disclosure can be applied to tire molding molds.

1: Lower container 10: Plate portion 100: Mold (mold for forming tires)
11: Lower sidewall molding portion 12: Hole portion 12a: First connecting hole 12b: Second connecting hole 13: Locking hole 19: Wall portion 2: Upper container 20: Plate portion 200: Tire 21: Upper sidewall molding portion 3: Tread molding portion 4: Piece (segment piece)
[0033] 40: Split mold 41: Holder 41A: Outer portion 41B: Piece outer inclined surface 41H: Screw hole 41a: Locking hole 41b: Through hole 42: Arm portion 42a: Contact portion 42b: Base portion 42c: Pillar portion 43: Recess 44: Recess 45: Recess 46: Pressing portion 47: Pressing portion 48: Circumferentially pressing portion 49: Piston 49a: Rod-shaped portion 49b: Branch portion 49c: Pressing projection 5: Connecting pin 51: Enlarged diameter portion 52: Pressing portion 6: First guide rail 61: Lower end portion 62: Upper end side 64: Male screw member 65: Insertion hole 7: Ring (outer ring)
70: Ring outer periphery 71: Ring outer inclined surface 72: Projection 75: Ring inner periphery 76: Ring inner inclined surface 77: Through hole 8: Second guide rail 80: Space 85: Lower end 86: Upper end G: Axis

Claims

a circular tread molding portion divided into a plurality of segment pieces arranged in a circumferential direction;
an outer ring that is disposed axially above the tread molded portion and moves along the axial direction of the tread molded portion to open and close the tread molded portion in a radial direction;
the outer ring is engaged with each of the segment pieces;
The segment pieces are opened and closed in the radial direction in accordance with the movement of the outer ring, and are moved away from and close to adjacent segment pieces.
the outer ring has a ring outer peripheral portion formed with a ring outer inclined surface that faces outward in the radial direction and is inclined so that the diameter gradually decreases upward in the axial direction,
The segment piece has an arm portion that engages with an outer circumferential portion of the ring,
The arm portion has an abutment portion that abuts against the ring outer inclined surface,
the abutment portion moves downward relative to the ring outer peripheral portion along the ring outer inclined surface as the outer ring moves upward,
The segment piece is
the abutting portion moves downward relative to the outer circumferential portion of the ring, and the abutting portion opens in the radial direction;
2. The tire mold according to claim 1, wherein adjacent segment pieces are spaced apart when opened.
The tire molding mold according to claim 2, further comprising a biasing portion disposed on the segment piece and biasing the segment piece outward in the radial direction.
The tire molding mold according to claim 3, wherein the segment piece is journaled at its lower portion in the axial direction and is capable of rotating at its upper portion along the radial direction.
the segment piece has a first guide rail extending along the axial direction on an outer periphery of an outer piece in the radial direction and gradually inclining inward in the radial direction as it moves upward in the axial direction,
the outer ring has a second guide rail extending along the axial direction on an inner peripheral portion of the ring facing inward in the radial direction and gradually inclining inward in the radial direction as it moves upward in the axial direction,
The first guide rail is
The second guide rail is engaged with and guided by the second guide rail.
As the outer ring moves upward, the second guide rail moves downward relative to the outer ring.
The segment piece is
The first guide rail is opened radially in response to a downward movement of the first guide rail relative to the second guide rail,
2. The tire mold according to claim 1, wherein adjacent segment pieces are spaced apart when opened.
a piece outer circumferential portion is formed with a piece outer inclined surface that extends along the axial direction and is gradually inclined inward in the radial direction as it extends upward in the axial direction,
The first guide rail is
The piece is arranged along the outer inclined surface,
The piece is fixed to the outer periphery thereof by a male screw member,
The outer ring is formed with a screw-tightening through hole that penetrates along the axis of the thread of the male screw member,
The male screw member has a head disposed on the outer side in the radial direction and a threaded portion disposed on the inner side in the radial direction, and the screw fastening through hole is disposed so as to overlap with the second guide rail when viewed along the radial direction,
6. The tire molding mold according to claim 5, wherein the outer ring and the first guide rail overlap when viewed along the radial direction, and the first guide rail is guided by the second guide rail, and an axis of the screw-tightening through hole overlaps with an axis of a screw of the male threaded member.