JP7469638B2 - Tire vulcanization method - Google Patents

Description

The present invention relates to a tire vulcanization method , and more particularly to a tire vulcanization method capable of suppressing temperature variations between portions of a tire vulcanization mold caused by mold opening, thereby producing high-quality tires.

To vulcanize tires, a sectional type tire vulcanization mold consisting of an upper side mold, a lower side mold, and multiple sector molds is used (see, for example, Patent Document 1). With this type of tire vulcanization mold, the mold is opened widely when inserting a green tire into the mold and when removing the vulcanized tire from the mold.

The upper side mold, lower side mold, and sector mold are attached to the upper plate, lower plate, and segment that make up the vulcanization container, respectively. When the mold is closed, it is heated by heat sources such as the heating medium that flows through the bolster plate and container ring that make up the tire vulcanization container. On the other hand, when the mold is opened widely, these heat sources generally move to positions away from the mold. In particular, the heat sources move to positions farther away from the sector mold. Therefore, the sector mold tends to temporarily have a lower temperature than other parts of the mold. Such temperature differences between parts of the mold pose a risk of leading to variations in the degree of vulcanization of manufactured tires. Therefore, there is room for improvement in suppressing the temperature variations between parts of the mold that occur due to mold opening.

Japanese Patent Application Laid-Open No. 10-286833

An object of the present invention is to provide a tire vulcanization method capable of suppressing temperature variations between parts of a tire vulcanization mold caused by mold opening, thereby producing high-quality tires.

In order to achieve the above object, the tire vulcanization method of the present invention comprises the steps of: installing a tire vulcanization container having segments, each of which has a plurality of sector molds arranged in an annular shape attached to its inner circumferential surface, an upper plate having an upper side mold attached to its underside, and a lower plate having a lower side mold attached to its upper surface, with a central mechanism located in the center of the container in a plan view; making each of the segments movable toward and away from the central mechanism while being sandwiched vertically between the upper plate and the lower plate; placing a green tire in a laid-down state on the lower side mold; and moving each of the segments toward the central mechanism to vulcanize the tire in an annular shape. In a tire vulcanization method for assembling a green tire into a tire vulcanization container, enclosing the green tire inside the tire vulcanization container to close the tire, and vulcanizing the green tire by applying pressure and heat, the tire vulcanization container is placed on a lower cylinder mechanism that constitutes a lower structure and moves up and down, and an upper cylinder mechanism that constitutes an upper structure and moves up and down is placed on the tire vulcanization container, the upper structure is made vertically movable together with the upper plate and the upper side mold, and the lower structure is inserted into the lower end portions of each of the segments and is moved upwardly from the bottom toward the center of the tire vulcanization container in a plan view, a lower guide portion for guiding the tire vulcanization container, and the upper structure has an upper guide portion that abuts against an outer peripheral surface of each of the segments and guides each of the segments along the inclination direction, and a heat source portion is provided inside the upper plate, the lower plate, the upper guide portion and the lower guide portion, and when the green tire is enclosed inside and the mold is closed, the lower cylinder mechanism and the upper cylinder mechanism are operated to raise the vertical position of the tire vulcanization container between the lower structure and the upper structure set at a vulcanization execution position, and each of the segments is guided by the lower guide portion and the upper guide portion. and moving the segments closer to the central mechanism, thereby assembling the segments in a ring-shaped manner sandwiched between the upper side mold and the lower side mold, and when opening the mold after vulcanizing the green tire, the lower cylinder mechanism and the upper cylinder mechanism are operated to lower the vertical position of the tire vulcanization container between the lower structure and the upper structure set at the vulcanization position, and each of the segments is guided by the lower guide portion and the upper guide portion to move away from the central mechanism, thereby eliminating the ring-shaped assembly in which the segments are sandwiched between the upper side mold and the lower side mold from above and below .

According to the present invention, when the mold is opened with the upper structure and the lower structure set in the vulcanization position, the upper side mold contacts the upper plate in which the heat source is installed, the lower side mold contacts the lower plate in which the heat source is installed, and each sector mold contacts the lower guide part and the upper guide part in which the heat source is installed through each segment, so that the temperature difference between the upper side mold, the lower side mold, and each sector mold is suppressed. Then, when the upper structure is moved upward together with the upper plate and the upper side mold to open the mold in order to put a green tire into the mold or to remove a vulcanized tire from the mold, the lower guide part maintains contact even if the upper guide part separates from each segment, so that the temperature of each sector mold does not drop significantly. As a result, the temperature difference between the parts of the mold caused by the mold opening in the vulcanization process is suppressed, so that the variation in the degree of vulcanization in the manufactured tires is reduced, which is advantageous for manufacturing tires with excellent quality.

FIG. 2 is an explanatory diagram illustrating the left half of a tire vulcanizing apparatus used in the present invention in vertical cross section. FIG. 2 is an explanatory diagram illustrating the tire vulcanization container of FIG. 1 in a vertical cross-sectional view. FIG. 3 is an explanatory diagram illustrating the container of FIG. 2 in a plan view. 2 is an explanatory diagram illustrating the central mechanism, the upper structure, and the lower structure of FIG. 1 in vertical cross section. FIG. 5 is an explanatory diagram illustrating the upper structure of FIG. 4 in a plan view. 6 is an explanatory diagram illustrating the lower structure and the central mechanism of FIG. 5 in a plan view. FIG. FIG. 13 is an explanatory diagram illustrating a vertical cross-sectional view of the left half of the vulcanizing device in a state in which the container is installed between the upper structure and the lower structure. FIG. 8 is an explanatory diagram illustrating the upper structure, the segments, and the sector mold of FIG. 7 in a plan view. 9 is an explanatory diagram illustrating a vertical cross-sectional view of the mold in FIG. 8 in an open state. FIG. FIG. 10 is an explanatory diagram illustrating the upper structure, the segments, and the sector mold of FIG. 9 in a plan view. FIG. 10 is an explanatory diagram illustrating a state in which the upper structure of FIG. 9 is moved upward together with the upper plate and the upper side mold to open the mold and to insert a green tire. FIG. 12 is an explanatory diagram illustrating a vertical cross-sectional view of the upper structure of FIG. 11 placed on a container. FIG. 13 is an explanatory diagram illustrating a state in which the container in FIG. 12 is moved upward to close the mold.

Hereinafter, a tire vulcanization method of the present invention will be described based on an embodiment shown in the drawings.

A tire vulcanizing apparatus 1 (hereinafter referred to as the vulcanizing apparatus 1) used in the present invention shown in Fig. 1 has a tire vulcanizing container 2 (hereinafter referred to as the container 2) shown in Fig. 2 and Fig. 3, and a central mechanism 10, an upper structure 6, a lower structure 7, and an opening/closing mechanism 8 shown in Fig. 4 and Fig. 5. Sectional type molds 12 (12a, 12b, 12c) are attached to this container 2. The mold 12 corresponding to the green tire T to be vulcanized is attached to the container 2.

As illustrated in Figures 2 and 3, the container 2 has an upper plate 3, a lower plate 5, and a number of segments 5 arranged in a ring shape. An annular upper side mold 12a is attached to the lower surface of the upper plate 3. An annular lower side mold 12b is attached to the upper surface of the lower plate 4. A sector mold 12c is attached to the inner peripheral surface of each segment 5, and each sector mold 12c is arranged in a ring shape. The outer peripheral surface of each segment 5 is an inclined surface that slopes from the bottom to the top toward the center of the container 2 in a plan view. In other words, the outer peripheral surface of each segment 5 slopes upward from the outer peripheral side. A recess 5a is formed at the lower end of each segment 5. This recess 5a has an inclined surface that slopes in the same direction as the outer peripheral surface of the segment 5.

The central mechanism 10 is disposed in the center of the container 2 in a plan view. The central post 10a constituting the central mechanism 10 is disposed at the center CL of the annular shape of the upper side mold 12a and the lower side mold 12b. Each segment 5 (sector mold 12c) is disposed in a ring shape centered on the central mechanism 10 (center CL), and moves toward and away from the central mechanism 10 while being sandwiched vertically between the upper plate 3 and the lower plate 4.

Disc-shaped clamping parts 11a are attached to the central post 10a at intervals above and below. Each clamping part 11a detachably holds the upper and lower ends of a cylindrical vulcanization bladder 11. The central mechanism 10 is vertically movable, and the vertical intervals between each clamping part 11a are also variable.

As shown in Figures 4 and 5, the upper structure 6 is a cylindrical body with an open lower end, and has an upper cylinder mechanism 6a and an upper guide portion 6b that move up and down. The upper cylinder mechanism 6a is installed so as to be suspended from the upper surface inside the cylindrical body. The upper cylinder mechanism 6a is placed on the container 2 when vulcanizing the green tire T. A hydraulic cylinder mechanism or the like is used as the upper cylinder mechanism 6a. In this embodiment, a single hydraulic cylinder mechanism that is annular in plan view and centered on the central mechanism 10 is used as the upper cylinder mechanism 6a.

The upper guide portion 6b corresponds to the peripheral wall of the cylindrical upper structure 6 and contacts the outer peripheral surface of each segment 5. The inner peripheral surface of the upper guide portion 6b, which faces the outer peripheral surface of the segment 5, is inclined in the same direction as the outer peripheral surface of the segment 5. The upper guide portion 6b guides each segment 5 along the inclination direction of the outer peripheral surface of each segment 5.

As shown in Figures 4 and 6, the lower structure 7 is a cylindrical body with an open upper end, and has a lower cylinder mechanism 7a and a lower guide portion 7b that move up and down. The lower cylinder mechanism 7a is installed on the inner underside of this cylindrical body. When vulcanizing the green tire T, the container 2 is placed on the lower cylinder mechanism 7a. A hydraulic cylinder mechanism or the like is used as the lower cylinder mechanism 7a. In this embodiment, a single hydraulic cylinder mechanism that is annular in plan view and centered on the central mechanism 10 is used as the lower cylinder mechanism 7a.

The lower guide portion 7b corresponds to the peripheral wall of the cylindrical lower structure 7, and is inserted into the recess 5a formed at the lower end of each segment 5. The outer peripheral surface of the lower guide portion 7b facing the recess 5a is inclined in the same direction as the outer peripheral surface of the segment 5. The lower guide portion 7b guides each segment 5 along the inclination direction of the outer peripheral surface of each segment 5.

The opening and closing mechanism 8 moves the upper structure 6 up and down together with the upper plate 3 and the upper side mold 12a. A hydraulic cylinder mechanism or the like is used as the opening and closing mechanism 8, and the lower end of the cylinder rod of the opening and closing mechanism 8 is connected to the upper surface of the upper structure 6. By contracting the cylinder rod of the opening and closing mechanism 8, the upper structure 6 moves away from the lower structure 7 and the central mechanism 10, and by extending the cylinder rod, the upper structure 6 moves closer to the lower structure 7 and the central mechanism 10. The opening and closing mechanism 8, the upper cylinder mechanism 6a, and the lower cylinder mechanism 7a can operate independently of each other.

The upper plate 3, the lower plate 4, the upper guide portion 6b, and the lower guide portion 7b each have a heat source portion 9 disposed therein. The heat source portion 9 is a portion that heats the mold 12. In this embodiment, the heat source portion 9 is a flow path through which steam or the like flows.

Next, we will explain an example of a method for vulcanizing a green tire T using this vulcanizing device 1 to manufacture a pneumatic tire.

First, as shown in FIG. 7, the container 2 is placed between the upper structure 6 and the lower structure 7. The upper structure 6 is then moved upward by the opening/closing mechanism 8 relative to the lower structure 7, which is positioned so that the central mechanism 10 is located in the center when viewed from above, to create a large vertical distance between them.

Next, as shown in FIG. 1, the container 2 with the mold 12 attached is placed on the lower cylinder mechanism 7a and set up so that the central mechanism 10 is located in the center of the container 2 in a plan view. At this time, the cylinder rod of the lower cylinder mechanism 7a is extended. The lower guide portion 7b is inserted into the recessed portion 5a of each segment 5. The lower guide portion 7b is inserted halfway into the recessed portion 5a and does not reach the top end of the recessed portion 5a.

Next, as shown in FIG. 7, the upper structure 6 is moved downward, the upper cylinder mechanism 6a is placed on the upper plate 3, and the container 2 is placed between the upper structure 6 and the lower structure 7. At this time, the cylinder rod of the upper cylinder mechanism 6a is contracted. The upper guide portion 6b abuts against the outer peripheral surface of each segment 5. This position of the upper structure 6 and the lower structure 7 becomes the vulcanization position.

Each segment 5 is sandwiched vertically between the upper plate 3 and the lower plate 4. Each sector mold 12c, which is sandwiched vertically between the upper side mold 12a and the lower side mold 12b, is assembled in an annular shape as shown in FIG. 8, and the mold 12 is in a closed state.

Next, as shown in FIG. 9, while the upper structure 6 and the lower structure 7 are kept set in the vulcanization position, the cylinder rod of the upper cylinder mechanism 6a is extended and the cylinder rod of the lower cylinder mechanism 7a is contracted. This lowers the vertical position of the container 2 between the upper structure 6 and the lower structure 7 set in the vulcanization position. As a result, the lower guide portion 7b is inserted deeper into the recesses 5a of each segment 5, and the upper guide portion 6b moves relatively upward along the outer circumferential surface of each segment 5. The central mechanism 10 is also moved downward to match the container 2.

As the container 2 moves downward, each segment 5 is guided by the upper guide portion 6b and the lower guide portion 7b and moves away from the central mechanism 10. As a result, while each sector mold 12c is sandwiched between the upper side mold 12a and the lower side mold 12b from above and below, the annular assembly is released and the mold 12 is in an open state, as illustrated in FIG. 10.

Next, in order to insert the green tire T into the mold 12, the upper structure 6 is moved upward together with the upper plate 3 and the upper side mold 12a, as illustrated in FIG. 11, to sufficiently separate the upper side mold 12a from each sector mold 12c in the vertical direction.

Next, the green tire T in a lying state is inserted into the central mechanism 10, and the green tire T is held by the vulcanization bladder 11 inflated with shaping pressure. This green tire T is placed on the lower side mold 12b.

Next, as shown in FIG. 12, the upper structure 6 is moved downward together with the upper plate 3 and the upper side mold 12a, the upper side mold 12a is placed on each sector mold 12c, and the upper plate 3 is placed on each segment 5. The lower guide portion 7b is inserted deeper into the recessed portion 5a of each segment 5, and the upper guide portion 6b abuts against the upper end of the outer circumferential surface of each segment 5, and the mold 12 is in an open state.

Next, as shown in FIG. 13, while the upper structure 6 and the lower structure 7 are kept set in the vulcanization position, the cylinder rod of the upper cylinder mechanism 6a is contracted and the cylinder rod of the lower cylinder mechanism 7a is extended. This raises the vertical position of the container 2 between the upper structure 6 and the lower structure 7 set in the vulcanization position. As a result, the lower guide portion 7b is inserted less deeply into the recesses 5a of each segment 5, and the upper guide portion 6b moves relatively downward along the outer circumferential surface of each segment 5. The central mechanism 10 is also moved upward in accordance with the container 2.

As the container 2 moves upward, each segment 5 is guided by the upper guide portion 6b and the lower guide portion 7b and moves closer to the central mechanism 10. As a result, each sector mold 12c is assembled in an annular shape, sandwiched vertically between the upper side mold 12a and the lower side mold 12b. Thus, the green tire T is trapped inside and the mold is closed.

In the closed mold 12, the vulcanization bladder 11 is further expanded inside the green tire T to apply a predetermined internal pressure to the green tire T, and the tire is heated to a predetermined temperature using the heat source 9 to vulcanize it. The green tire T is vulcanized for a predetermined time to complete a pneumatic tire.

When opening the mold after vulcanizing the green tire T, as shown in FIG. 9, the upper structure 6 and the lower structure 7 are kept set in the vulcanization position, and the cylinder rod of the upper cylinder mechanism 6a is extended and the cylinder rod of the lower cylinder mechanism 7a is contracted. This lowers the vertical position of the container 2 between the upper structure 6 and the lower structure 7 set in the vulcanization position. The central mechanism 10 is also moved downward to match the container 2.

As the container 2 moves downward, each segment 5 is guided by the upper guide portion 6b and the lower guide portion 7b and moves away from the central mechanism 10. As a result, each sector mold 12c is sandwiched vertically between the upper side mold 12a and the lower side mold 12b, and the annular assembly is released and the mold 12 is in an open state, as shown in FIG. 10.

Next, in order to remove the vulcanized tire from inside the mold 12, as illustrated in FIG. 11, the upper structure 6 is moved upward together with the upper plate 3 and the upper side mold 12a to sufficiently separate the upper side mold 12a from each sector mold 12c in the vertical direction. After that, the vulcanized tire is removed to the outside of the vulcanizer 1.

According to the present invention, when the mold 12 is opened with the upper structure 6 and the lower structure 7 set in the vulcanization position, as illustrated in FIG. 12, the upper side mold 12a is in contact with the upper plate 3 in which the heat source 9 is provided, and the lower side mold 12b is in contact with the lower plate 4 in which the heat source 9 is provided. In addition, each sector mold 12c is in contact with the upper guide portion 6b and the lower guide portion 7b in which the heat source 9 is provided via each segment 5, so that the temperature difference between the upper side mold 12a, the lower side mold 12b, and each sector mold 12c is suppressed.

When the upper structure 6 is moved upward together with the upper plate 3 and the upper side mold 12a to open the mold in order to insert the green tire T into the mold 12 and to remove the vulcanized tire from the mold 12, as shown in FIG. 11, the lower guide portion 7b remains in contact with each segment 5 even if the upper guide portion 6b separates from each segment 5, so the temperature of each sector mold 12c does not drop significantly.

As a result, the temperature difference between parts of the mold 12 caused by opening the mold during the vulcanization process is suppressed. Therefore, even when manufacturing tires by sequentially and continuously vulcanizing green tires T, the variation in the degree of vulcanization in the manufactured tires is reduced, which is advantageous for manufacturing high-quality tires.

This is also beneficial in reducing the energy used in tire manufacturing, as the temperature of the heated mold 12 is prevented from dropping significantly each time the mold is opened. The container 2 can be replaced (installed and removed) by moving the container 2 as a whole, reducing the workload.

The upper cylinder mechanism 6a and the lower cylinder mechanism 7a are not limited to the above-mentioned configuration, and may have other configurations. For example, the upper cylinder mechanism 6a and the lower cylinder mechanism 7a may each be configured with a plurality of cylinder mechanisms spaced apart in the circumferential direction around the central mechanism 10 (central post 10a) in a plan view.

Reference Signs List 1 Vulcanization device 2 Container 3 Upper plate 4 Lower plate 5 Segment 5a Recess 6 Upper structure 6a Upper cylinder mechanism 6b Upper guide section 7 Lower structure 7a Lower cylinder mechanism 7b Lower guide section 8 Opening/closing mechanism 9 Heat source section 10 Center mechanism 10a Center post 11 Vulcanization bladder 11a Clamp section 12 Mold 12a Upper side mold 12b Lower side mold 12c Sector mold T Green tire

Claims (3)

A tire vulcanization method comprising the steps of: installing a tire vulcanization container having segments, each of which has a plurality of sector molds arranged in an annular shape attached to its inner circumferential surface, an upper plate having an upper side mold attached to its underside, and a lower plate having a lower side mold attached to its upper surface, with a central mechanism located in the center of the container when viewed from above; allowing each of the segments to be moved toward and away from the central mechanism while being sandwiched vertically between the upper plate and the lower plate; placing a green tire in a lying state on the lower side mold; moving each of the segments toward the central mechanism to assemble them in an annular shape; enclosing the green tire inside to close the mold; and vulcanizing the green tire by applying pressure and heat,
The tire vulcanization container is placed on a lower cylinder mechanism that moves up and down and constitutes a lower structure, and an upper cylinder mechanism that moves up and down and constitutes an upper structure is placed on the tire vulcanization container, so that the upper structure can be moved up and down together with the upper plate and the upper side mold,
The lower structure has a lower guide portion that is inserted into a lower end portion of each of the segments and guides each of the segments from below to above along an inclined direction approaching a center portion of the tire vulcanization container in a plan view,
the upper structure has an upper guide portion that abuts against an outer peripheral surface of each of the segments and guides each of the segments along the inclination direction,
a heat source unit is provided inside the upper plate, the lower plate, the upper guide unit, and the lower guide unit,
When the green tire is enclosed inside and the mold is closed, the lower cylinder mechanism and the upper cylinder mechanism are operated to raise the vertical position of the tire vulcanization container between the lower structure and the upper structure set at the vulcanization position, and each of the segments is guided by the lower guide portion and the upper guide portion to move close to the central mechanism, thereby assembling the segments in a ring shape while being sandwiched between the upper side mold and the lower side mold,
A tire vulcanization method characterized in that, when opening the mold after vulcanizing the green tire, the lower cylinder mechanism and the upper cylinder mechanism are operated to lower the vertical position of the tire vulcanization container between the lower structure and the upper structure set at the vulcanization position, and each of the segments is guided by the lower guide portion and the upper guide portion to move away from the central mechanism, thereby eliminating the annular assembly while being sandwiched vertically between the upper side mold and the lower side mold. The tire vulcanization method according to claim 1 , wherein each of the lower cylinder mechanism and the upper cylinder mechanism is a single hydraulic cylinder mechanism having an annular shape centered on the central mechanism in a plan view. The tire vulcanization method according to claim 1 , wherein a plurality of cylinder mechanisms are used as the lower cylinder mechanism and the upper cylinder mechanism, the cylinder mechanisms being arranged at intervals in the circumferential direction around the central mechanism in a plan view .

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