CN117984594A

CN117984594A - Tire secondary vulcanization expansion method and device

Info

Publication number: CN117984594A
Application number: CN202311305171.0A
Authority: CN
Inventors: 原田航平
Original assignee: Yokohama Rubber Co Ltd
Current assignee: Yokohama Rubber Co Ltd
Priority date: 2022-11-02
Filing date: 2023-10-10
Publication date: 2024-05-07
Also published as: JP2024066569A

Abstract

Provided are a secondary vulcanization expansion method and device for a tire, which can more reliably expand the tire even when the vertical interval between bead portions immediately after vulcanization is too small. The tire (T) is inflated by injecting a cooling medium (C) into the tire (T) through an injection part (6) while the vertical interval of the holding parts (5 a, 5 b) is expanded from the injection holding interval (Di) to a preset reference interval (Dc) and the inflated state of the tire (T) is maintained by using the pair of upper and lower holding parts (5 a, 5 b) to hold the vertical bead parts (Tb) of the tire (T) after transverse vulcanization, and making the vertical interval of the holding parts (5 a, 5 b) be smaller than the vertical interval (Db) of the vertical bead parts (Tb) of the tire (T) after vulcanization.

Description

Tire secondary vulcanization expansion method and device

Technical Field

The present invention relates to a method and an apparatus for secondary vulcanization expansion (post cure inflation) of a tire, and more particularly, to a method and an apparatus for secondary vulcanization expansion of a tire, which can more reliably expand a tire even when the vertical spacing between the bead portions of the tire immediately after vulcanization is too small.

Background

If a tire using an organic fiber cord as a reinforcing material is naturally cooled after vulcanization, the organic fiber cord may shrink too much and deform into an improper tire shape. In order to prevent such a problem, a secondary vulcanization expansion step (hereinafter, referred to as a PCI step) of cooling the tire immediately after vulcanization by injecting a cooling medium such as air into the tire to expand the tire is performed. Various devices for performing the PCI process have been proposed (for example, refer to patent documents 1 and 2).

In recent years, due to weight reduction of tires, tire side portions become thin, and as a result, in tires immediately after horizontal vulcanization, there are cases where the vertical distance between the upper and lower bead portions becomes too small. In the PCI process, the upper and lower bead portions are held by the pair of upper and lower holding portions to expand the tire, but when the upper and lower intervals of the upper and lower bead portions are excessively small, a gap is generated between the upper portion of the tire held by the lower holding portion and the upper holding portion. When the tire is inflated, the cooling medium flows out from the gap, and therefore the tire cannot be inflated sufficiently, and the PCI process cannot be performed. Accordingly, there is room for improvement in expanding the tire more reliably even when the vertical distance between the upper and lower bead portions of the tire immediately after vulcanization is too small.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 1-154714

Patent document 2: japanese patent laid-open No. 6-285871

Disclosure of Invention

Problems to be solved by the invention

The purpose of the present invention is to provide a secondary vulcanization expansion method and device for a tire, which can more reliably expand the tire even when the vertical distance between the upper and lower bead portions of the tire immediately after vulcanization is too small.

Means for solving the problems

In order to achieve the above object, a tire secondary vulcanization expansion method according to the present invention is a tire secondary vulcanization expansion method for maintaining an inflated state of a tire by holding upper and lower bead portions of a tire after being vulcanized in a horizontal direction by a pair of upper and lower holding portions and injecting a cooling medium into the tire, wherein the tire is maintained in an inflated state by expanding an upper and lower holding gap of the pair of upper and lower holding portions from the inflated state to a preset reference gap while expanding the tire by the cooling medium by setting the upper and lower holding gap of the pair of upper and lower holding portions to be smaller than an upper and lower holding gap of the bead portions of the tire after being vulcanized in a horizontal direction, so that the pair of upper and lower holding portions are respectively in annular contact with the tire in a continuous circumferential direction.

The tire secondary vulcanization expansion device of the present invention comprises: a pair of upper and lower holding portions that hold upper and lower bead portions of a tire immediately after vulcanization, which is laid sideways; and an injection unit that injects a cooling medium into the tire, wherein the tire secondary vulcanization expansion device maintains the tire in an expanded state by the cooling medium, wherein the tire secondary vulcanization expansion device includes a gap narrowing mechanism that reduces an upper-lower gap between the bead portions of the tire immediately after horizontal vulcanization, and wherein the gap narrowing mechanism causes the upper-lower gap between the upper and lower pair of holding portions to be a holding gap at injection time that is smaller than the upper-lower gap between the bead portions of the tire immediately after horizontal vulcanization, whereby the upper and lower pair of holding portions are respectively brought into contact with the tire in a ring shape that is continuous in the circumferential direction, and the tire is expanded by the cooling medium while expanding the tire, thereby expanding the upper-lower gap between the upper and lower pair of holding portions from the holding gap at injection time to a preset reference gap, and maintaining the tire in an expanded state.

Effects of the invention

According to the present invention, the pair of upper and lower holding portions are brought into contact with the tire in a ring shape continuously in the circumferential direction by making the holding interval at the time of injection smaller than the vertical interval between the upper and lower bead portions of the tire immediately after horizontal vulcanization. Therefore, even when the vertical interval between the bead portions in the upper and lower sides of the tire immediately after vulcanization is too narrow, it is advantageous to reliably expand the tire by injecting the cooling medium into the tire. Further, since the vertical interval between the pair of upper and lower holding portions is increased from the injection holding interval to the reference interval and maintained in the inflated state, the tire can be subjected to an appropriate PCI process to ensure excellent tire quality.

Drawings

Fig. 1 is an explanatory diagram illustrating an embodiment of a PCI device in a front view with a tire in section.

Fig. 2 is an explanatory diagram illustrating the PCI device of fig. 1 in a plan view.

Fig. 3 is a cross-sectional view A-A of fig. 1.

Fig. 4 is an explanatory view illustrating an operation of the engagement portion of fig. 3.

Fig. 5 is an explanatory view illustrating a state in which a tire immediately after vulcanization is placed on the lower holding portion.

Fig. 6 is an explanatory diagram illustrating a state in which the upper shaft and the lower shaft of fig. 5 are coupled.

Fig. 7 is an explanatory view illustrating a state in which the upper and lower intervals between the upper and lower pair of holding portions in fig. 6 are set to the injection holding intervals.

Fig. 8 is an explanatory view illustrating a state in which the vertical interval between the pair of upper and lower holding portions in fig. 7 is enlarged to the reference interval.

Fig. 9 is an explanatory diagram illustrating another embodiment of the PCI device in a front view with the tire in a cross-section.

Fig. 10 is an explanatory diagram illustrating the PCI device of fig. 9 in a plan view.

Fig. 11 is an explanatory view illustrating a state in which the vertical interval between the pair of upper and lower holding portions in fig. 9 is set to the injection holding interval.

Fig. 12 is an explanatory diagram illustrating another embodiment of the PCI device in a front view with the tire in a cross-section.

Fig. 13 is an explanatory view illustrating a state in which the vertical interval between the pair of upper and lower holding portions in fig. 12 is set to the injection holding interval.

Fig. 14 is an explanatory diagram illustrating another embodiment of the PCI device in a front view with the tire in a cross-section.

Fig. 15 is an explanatory view illustrating a state in which the vertical interval between the pair of upper and lower holding portions in fig. 14 is set to the injection holding interval.

Description of the reference numerals

1 PCI device

2. Support shaft

2A upper shaft

2B lower shaft

3. Engagement portion

4. Connector for connecting with a plurality of wires

4A engaging portion

4B through hole

5A one holding portion

5B holding portion of the other

6. Injection part

6A filling port

7. Spacing reducing mechanism

8. Holding part moving mechanism

9. Gap sensor

10. 10A, 10b pressure sensor

11. Control unit

Tire with T-vulcanized structure

Tb bead portion

C cooling medium

Upper and lower bead portions immediately after Db vulcanization are spaced apart from each other

Maintaining spacing during Di implantation

Dc reference interval

Detailed Description

The secondary vulcanization expansion method and apparatus for a tire according to the present invention will be described below with reference to the embodiments shown in the drawings.

The secondary vulcanization expansion process (hereinafter, referred to as a PCI process) is performed using the embodiment of the secondary vulcanization expansion device 1 (hereinafter, referred to as the PCI device 1) illustrated in fig. 1 to 4. The step of performing the PCI process is the secondary vulcanization expansion method of the present invention (hereinafter, PCI method).

The tire T is embedded with a heat-shrinkable fiber cord as a reinforcing material (carcass material or the like). Therefore, if the tire T is naturally cooled after vulcanization, the tire T is unnecessarily deformed as the fiber cord is thermally contracted. Therefore, by cooling the tire T immediately after vulcanization in an expanded state (by performing the PCI process), unnecessary deformation of the tire T is avoided against thermal contraction of the fiber cord. The PCI step is performed by putting the tire T immediately after vulcanization into a sideways state. In the tire T lying sideways, the two annular bead portions Tb are in a state of facing each other vertically.

The PCI device 1 includes: a pair of upper and lower holding portions 5a, 5b, the pair of upper and lower holding portions 5a, 5b holding upper and lower bead portions Tb of the tire T immediately after vulcanization; holding part moving mechanisms 8, 8; an injection unit 6, the injection unit 6 injecting a cooling medium C into the tire T; a gap sensor 9; a pressure sensor 10, the pressure sensor 10 detecting an internal pressure Pi of the tire T; a control unit 11.

In the PCI step, the vertical interval between the pair of upper and lower holding portions 5a, 5b is set to the reference interval Dc. The reference distance Dc is a vertical distance between the lowermost position of the upper holding portion 5a and the uppermost position of the lower holding portion 5 b. The reference distance Dc is substantially the same as the vertical distance between the pair of upper and lower bead portions Tb (the vertical distance between the lowermost position of the upper bead portion Tb and the uppermost position of the lower bead portion Tb) in the mold for vulcanizing the tire T. That is, the reference distance Dc is set to be substantially the same as the vertical distance between the pair of upper and lower bead portions Tb when the vulcanized tire T is positioned in the mold to which the mold is closed.

The upper holding portion 5a is attached to the upper shaft 2a, and the lower holding portion 5b is attached to the lower shaft 2b. The upper shaft 2a and the lower shaft 2b extend vertically coaxially, and can be coupled to and uncoupled from each other via the coupler 4. The upper shaft 2a and the lower shaft 2b are connected to form a single support shaft 2. The single-dot chain line CL in the figure indicates the axial center of the support shaft 2 (upper shaft 2a and lower shaft 2 b).

The support shaft 2 penetrates the center of the disk-shaped holding portions 5a and 5b in plan view. The upper shaft 2a and the lower shaft 2b move up and down to approach each other and to separate from each other. In this embodiment, an engaging portion 3 is fixed to the lower end of the upper shaft 2a, and a cylindrical coupler 4 is fixed to the upper end of the lower shaft 2 b.

As illustrated in fig. 3, the four engagement portions 3 extend radially from the upper shaft 2a centering on the axial center CL in a plan view. A through hole 4b having a shape corresponding to the upper shaft 2a and the four engaging portions 3 is formed in the upper surface of the coupler 4. By forming the through hole 4b, the engaging portion 4a is also formed on the upper surface of the coupler 4. The engaging portion 3 fixed to the lower end of the upper shaft 2a can be inserted into the through hole 4b vertically. In fig. 3, the inner peripheral edge of the tire T held by the lower holding portion 5b is indicated by a two-dot chain line.

When describing the connection structure of the upper shaft 2a and the lower shaft 2b in detail, as illustrated in fig. 4, if the upper shaft 2a is rotated about the axis CL by a drive motor or the like so that the through hole 4b matches the shape of the engagement portion 3 fixed to the lower end of the upper shaft 2a, the engagement portion 3 fixed to the lower end of the upper shaft 2a is inserted up and down through the through hole 4b by moving the upper shaft 2a up and down at the rotated position. After the engaging portion 3 is moved downward and inserted into the through hole 4b, if the upper shaft 2a is rotated about the axial center CL and the engaging portion 3 and the engaging portion 4a are positioned to overlap each other as illustrated in fig. 3, even if the upper shaft 2a is moved upward, the engaging portion 3 and the engaging portion 4a interfere with each other to restrict upward movement of the upper shaft 2a, and the upper shaft 2a and the lower shaft 2b are connected to each other to form 1 support shaft 2. In the case of disconnecting the upper shaft 2a and the lower shaft 2b, a step opposite to that in the case of connecting may be performed. The connection structure between the upper shaft 2a and the lower shaft 2b is not limited to the structure illustrated in this embodiment, and various known structures can be adopted.

The upper holding portion 5a holds an upper portion (a portion including the upper bead portion Tb) of the tire T lying sideways. The upper shaft 2a penetrates the upper holding portion 5a at the center in plan view, and a holding portion moving mechanism 8 (upper holding portion moving mechanism 8) for moving the upper holding portion 5a up and down with respect to the upper shaft 2a is provided in the upper holding portion 5 a. As the holding portion moving mechanism 8, a known mechanism that moves the upper holding portion 5a up and down by a fluid cylinder, a servo motor, or the like can be used. The upper holding portion 5a can be fixed at a predetermined upper and lower position of the upper shaft 2 a. The upper holding portion 5a can be moved up and down together with the upper shaft 2a by a fluid cylinder or the like, not shown.

The lower holding portion 5b holds a lower portion (a portion including the lower bead portion Tb) of the tire T lying sideways. The connecting portion 4 integrated with the lower shaft 2b penetrates the upper center portion of the lower holding portion 5b, and a holding portion moving mechanism 8 (lower holding portion moving mechanism 8) for moving the lower holding portion 5b up and down is provided in the lower holding portion 5 b. The lower holding portion 5b can be fixed at a predetermined upper and lower position of the coupler 4 (lower shaft 2 b) by a lower holding portion moving mechanism 8. The lower holding portion 5b is movable up and down together with the lower shaft 2b and the coupler 4. As the holding portion moving mechanism 8, a known mechanism that moves the lower holding portion 5b up and down by a fluid cylinder, a servo motor, or the like can be used.

The injection unit 6 injects a cooling medium C such as air into the tire T. As the injection portion 6, a known compressor or the like can be used. In this embodiment, the cooling medium C is injected into the tire T through the injection port 6a formed in the lower holding portion 5 b. The injection port 6a is not limited to the holding portion 5b formed on the lower side, and may be formed on the holding portion 5a, the support shaft 2, and the coupler 4 on the upper side, and may be formed not only on one site but also on a plurality of sites.

The holding portion moving mechanisms 8, 8 may be configured to reduce the vertical distance between the pair of holding portions 5a, 5b to a holding distance Di at the time of injection, which will be described later. If the vertical distance between the pair of holding parts 5a and 5b is reduced to the injection holding distance Di by vertically moving both the holding parts 5a and 5b, the holding part moving mechanisms 8 and 8 for vertically moving the holding parts 5a and 5b are required. If either one of the pair of upper and lower holding portions 5a, 5b is moved up and down to reduce the up-down interval between the two to the injection holding interval Di, the holding portion moving mechanism 8 may be provided to move either one of the holding portions 5a, 5b up and down.

The gap sensor 9 detects the up-down gap g between the upper holding portion 5a and the surface of the tire T (the peripheral portion of the upper bead portion Tb) facing the holding portion 5 a. The gap sensor 9 can use various known noncontact types such as a photoelectric sensor. The up-down gap g detected by the gap sensor 9 is input to the control unit 11. The gap sensor 9 is provided at a position circumferentially spaced apart from the axis CL. In this embodiment, the gap sensors 9 are preferably provided at 3 locations at equal intervals in the circumferential direction, and at 2 to 4 locations at equal intervals.

The pressure sensor 10 can use various types that are known and can detect the internal pressure Pi of the tire T. The internal pressure Pi detected by the pressure sensor 10 is input to the control unit 11.

The control unit 11 performs various arithmetic processing using the input data. The control unit 11 controls the operations of the constituent elements of the PCI device 1 based on the input data and the calculation result. As the control unit 11, various known computers can be used. The reference interval Dc is input to the control unit 11.

One of the features of the PCI device 1 is that the device has a gap narrowing mechanism 7, and the gap narrowing mechanism 7 makes the vertical gap between the pair of upper and lower holding portions 5a, 5b smaller than the vertical gap Db between the upper and lower bead portions Tb of the tire T immediately after horizontal vulcanization, and holds the gap Di at the time of injection. In this embodiment, the holding portion moving mechanism 8, the gap sensor 9, and the control portion 11, which move the lower holding portion 5b up and down, function as the interval narrowing mechanism 7.

An example of the procedure of the PCI process by the PCI method will be described below.

In the PCI device 1 illustrated in fig. 5, the upper shaft 2a and the upper holding portion 5a are located at standby positions that are substantially apart upward from the coupler 4, the lower shaft 2b, and the lower holding portion 5b. In a state where the upper shaft 2a and the upper holding portion 5a are located at the standby position, the tire T immediately after horizontal vulcanization is placed on and held by the lower holding portion 5b. The lower bead portion Tb is held by the lower holding portion 5b, and the uppermost position of the lower holding portion 5b is substantially at the same level as the uppermost position of the lower bead portion Tb.

In the case where the tire side portion is of a thin gauge, in the tire T immediately after the horizontal vulcanization, the bead portion Tb on the upper side tends to sag due to the influence of the decrease in rigidity of the tire side portion on the upper side. As a result, the vertical distance Db between the upper and lower bead portions Tb of the tire T is smaller than the reference distance Dc.

Next, as illustrated in fig. 6, the upper shaft 2a is moved downward from the standby position to the coupling position together with the upper holding portion 5 a. At this connection position, as illustrated in fig. 3 and 4, the engaging portion 3 and the engaging portion 4a are vertically overlapped, and the upper shaft 2a and the lower shaft 2b are connected to each other via the coupler 4 to form one support shaft 2. In this embodiment, as illustrated in fig. 6, the upper and lower intervals between the pair of upper and lower holding portions 5a, 5b are set to the reference interval Dc in a state where the upper shaft 2a and the lower shaft 2b are coupled.

Since the vertical gap Db between the upper and lower bead portions Tb is smaller than the reference gap Dc, a large vertical gap g is generated in the surface (peripheral portion of the upper bead portion Tb) of the upper holding portion 5a facing the holding portion 5a of the tire T. Accordingly, as illustrated in fig. 7, the upper shaft 2a and the upper holding portion 5a are held at a fixed vertical position, and the lower holding portion 5b is moved upward together with the lower shaft 2b and the coupler 4 by the lower holding portion moving mechanism 8 while detecting the vertical gap g by the gap sensor 9. The lower holding portion 5b is moved upward together with the lower shaft 2b and the coupler 4, and the vertical interval between the pair of upper and lower holding portions 5a, 5b is reduced until the vertical gap g detected by the gap sensor 9 becomes zero. The vertical interval between the pair of upper and lower holding portions 5a, 5b when the vertical gap g is zero becomes the injection holding interval Di.

By setting the vertical interval between the pair of upper and lower holding portions 5a, 5b to the injection holding interval Di, the pair of upper and lower holding portions 5a, 5b are respectively abutted against the tire T in a ring shape continuously in the circumferential direction. With this, the inner space of the tire T becomes a closed space surrounded by the tire T and the pair of upper and lower holding portions 5a, 5 b.

In the state of fig. 6, the upper holding portion 5a can be moved downward by the upper holding portion moving mechanism 8 while detecting the vertical gap g by the gap sensor 9 in a state where the vertical position of the upper shaft 2a is held fixed and the vertical position of the lower holding portion 5b is held fixed together with the lower shaft 2b and the coupler 4. The upper holding portion 5a is moved downward until the vertical gap g detected by the gap sensor 9 becomes zero, and the vertical gap between the pair of upper and lower holding portions 5a, 5b is set to the injection holding gap Di. By moving the upper holding portion 5a in this way, the pair of upper and lower holding portions 5a, 5b can be brought into contact with the tire T in a ring shape that is continuous in the circumferential direction.

In a state where the pair of upper and lower holding portions 5a, 5b are respectively in contact with the tire T in a ring shape that is continuous in the circumferential direction, the cooling medium C supplied from the injection portion 6 does not substantially flow out to the outside of the tire T, and therefore the tire T can be smoothly inflated by the cooling medium C. Accordingly, as illustrated in fig. 8, while the tire T is inflated by the cooling medium C injected into the tire T, the vertical interval between the pair of upper and lower holding portions 5a, 5b is increased from the injection-time holding interval Di to the preset reference interval Dc, and the tire T is maintained in the inflated state. When the vertical interval between the pair of upper and lower holding portions 5a, 5b is the reference interval Dc, the lowermost position of the upper holding portion 5a and the lowermost position of the upper bead portion Tb are at substantially the same level, and the uppermost position of the lower holding portion 5b and the uppermost position of the lower bead portion Tb are at substantially the same level.

In this embodiment, the upper shaft 2a and the upper holding portion 5a are kept fixed in the vertical position, and the lower holding portion 5b is allowed to move vertically together with the lower shaft 2b and the coupler 4. Accordingly, the upper and lower bead portions Tb are held by the upper and lower pair of holding portions 5a, 5b, respectively, to expand the tire T, and the lower holding portion 5b moves downward together with the lower shaft 2b and the coupler 4. By the engagement portion 4a moving downward interfering with the engagement portion 3, the downward movement of the lower holding portion 5b is stopped, and the vertical interval between the pair of upper and lower holding portions 5a, 5b is maintained at the reference interval Dc.

Further, the lower holding portion 5b can be moved downward together with the lower shaft 2b and the coupler 4by the lower holding portion moving mechanism 8, and the vertical interval between the pair of holding portions 5a and 5b can be increased from the injection holding interval Di to the reference interval Dc. Alternatively, the upper holding portion 5a may be moved upward by the upper holding portion moving mechanism 8, so that the vertical interval between the pair of upper and lower holding portions 5a, 5b may be increased from the injection holding interval Di to the reference interval Dc.

The control unit 11 controls the injection amount of the cooling medium C from the injection unit 6 so that the internal pressure Pi detected by the pressure sensor 10 falls within a predetermined range, and maintains the tire T in an inflated state and cools for a predetermined period of time. Then, after the lapse of a predetermined time, the PCI process is ended. Then, the upper shaft 2a and the lower shaft 2b are disconnected, the upper shaft 2a and the upper holding portion 5a are moved upward to the standby position, and the tire T after the completion of the PCI process is removed from the PCI device 1.

As described above, the pair of upper and lower holding portions 5a, 5b are brought into contact with the tire T in a state of being continuous in the circumferential direction by making the holding interval Di at the time of injection smaller than the upper and lower intervals Db of the upper and lower bead portions Tb of the tire T immediately after the transverse vulcanization. By setting this state, even when the vertical gap Db between the upper and lower bead portions Tb of the tire T immediately after vulcanization is excessively narrowed, it is advantageous to reliably expand the tire T by injecting the cooling medium C into the tire T. Next, the tire T is maintained in the inflated state by expanding the vertical interval between the pair of upper and lower holding portions 5a, 5b from the injection holding interval Di to the reference interval Dc, so that an appropriate PCI process can be performed on the tire T. As a result, deformation of the tire T due to thermal shrinkage of the fiber cord can be avoided, and excellent tire quality can be ensured.

Next, other embodiments will be described. The embodiment of the PCI device 1 illustrated in fig. 9 to 11 is different from embodiment 1 illustrated in fig. 1 to 4 in that a pressure sensor 10a is provided instead of the gap sensor 9, and the other configuration is substantially the same as embodiment 1. The pressure sensor 10a detects the outflow pressure Pa of the cooling medium C flowing out from the inside to the outside of the tire T through the up-down gap g of the surface (the peripheral portion of the upper bead portion Tb) of the upper holding portion 5a facing the holding portion 5a of the tire T.

The pressure sensor 10a may be of any known type capable of detecting the outflow pressure Pa of the cooling medium C. The outflow pressure Pa detected by the pressure sensor 10a is input to the control unit 11. The pressure sensor 10a is provided at a position circumferentially spaced apart from the axis CL. In this embodiment, the pressure sensors 10a are preferably provided at 3 locations at equal intervals in the circumferential direction, and at 2 to 4 locations at equal intervals. In this embodiment, the holding portion moving mechanism 8, the pressure sensor 10a, and the control portion 11, which move the lower holding portion 5b up and down, function as the interval narrowing mechanism 7.

An example of the steps of the PCI process according to this embodiment will be described below.

The same as in embodiment 1 is true except that the tire T is placed and held on the lower holding portion 5b as illustrated in fig. 9, and the upper shaft 2a and the lower shaft 2b are connected to each other via the coupler 4 to form one support shaft 2. A large up-down gap g exists between the upper holding portion 5a and the surface of the tire T (the peripheral portion of the upper bead portion Tb) facing the holding portion 5 a. Therefore, in this embodiment, the cooling medium C is injected from the injection portion 6 into the tire T, and the outflow pressure Pa of the cooling medium C flowing out from the up-down gap g is detected by the pressure sensor 10 a.

As illustrated in fig. 11, the cooling medium C is injected from the injection unit 6 into the tire T while maintaining the vertical positions of the upper shaft 2a and the upper holding unit 5a fixed, and the lower holding unit 5b is moved upward together with the lower shaft 2b and the coupler 4 while detecting the outflow pressure Pa by the pressure sensor 10 a. The lower holding portion 5b is moved upward together with the lower shaft 2b and the coupler 4, and the vertical interval between the pair of upper and lower holding portions 5a, 5b is reduced until the outflow pressure Pa detected by the pressure sensor 10a becomes zero. The vertical interval between the pair of upper and lower holding portions 5a, 5b at which the outflow pressure Pa becomes zero becomes the injection-time holding interval Di.

By setting the vertical interval between the pair of upper and lower holding portions 5a, 5b to the injection holding interval Di, the pair of upper and lower holding portions 5a, 5b are respectively abutted against the tire T in a ring shape continuously in the circumferential direction. With this, the inner space of the tire T becomes a closed space surrounded by the tire T and the pair of upper and lower holding portions 5a, 5 b. Therefore, as in embodiment 1, the tire T can be smoothly inflated by the cooling medium C. In addition, as in embodiment 1, while the tire T is inflated by the cooling medium C injected into the tire T, the vertical interval between the pair of upper and lower holding portions 5a, 5b is expanded from the injection-time holding interval Di to the preset reference interval Dc, and the tire T is maintained in the inflated state and cooled for a predetermined time.

The subsequent steps are the same as those of embodiment 1. In this embodiment, various modifications described in embodiment 1 can be performed.

Next, other embodiments will be described. The embodiment of the PCI device 1 illustrated in fig. 12 to 13 is different from embodiment 1 in that a pressure sensor 10b is provided instead of the gap sensor 9, and the other configuration is substantially the same as embodiment 1. The pressure sensor 10b detects the contact pressure Pb between the upper holding portion 5a and the surface of the tire T (the peripheral portion of the upper bead portion Tb) facing the holding portion 5 a.

The pressure sensor 10b can use various types known in the art that can detect the contact pressure Pb. The contact pressure Pb detected by the pressure sensor 10b is input to the control unit 11. The pressure sensors 10b are preferably disposed at positions circumferentially spaced apart from each other about the axis CL and at 2 to 4 positions circumferentially equally spaced apart from each other. In this embodiment, the holding portion moving mechanism 8, the pressure sensor 10b, and the control portion 11, which move the lower holding portion 5b up and down, function as the interval narrowing mechanism 7.

The same as in embodiment 1 is true except that the tire T is placed and held on the lower holding portion 5b as illustrated in fig. 12, and the upper shaft 2a and the lower shaft 2b are connected to each other via the coupler 4 to form one support shaft 2. A large up-down gap g exists between the upper holding portion 5a and the surface of the tire T (the peripheral portion of the upper bead portion Tb) facing the holding portion 5 a. Therefore, in the present embodiment, the contact pressure Pb is detected by the pressure sensor 10 b. In the presence of the up-down gap g, the contact pressure Pb becomes zero.

As illustrated in fig. 13, the lower holding portion 5b is moved upward together with the lower shaft 2b and the coupler 4 while detecting the contact pressure Pb by the pressure sensor 10b while the upper shaft 2a and the upper holding portion 5a are kept at a fixed vertical position. The lower holding portion 5b is moved upward together with the lower shaft 2b and the coupler 4, and the vertical interval between the pair of upper and lower holding portions 5a, 5b is reduced until the contact pressure Pb detected by the pressure sensor 10b rises to a preset reference value. The vertical interval between the pair of upper and lower holding portions 5a, 5b when the contact pressure Pb becomes the reference value becomes the injection holding interval Di. The reference value may be a minimum contact pressure Pb within a range where a preliminary test or the like can be performed to ensure that the pair of upper and lower holding portions 5a, 5b are continuously and annularly abutted against the tire T in the circumferential direction.

Next, other embodiments will be described. The embodiment of the PCI device 1 illustrated in fig. 14 to 15 differs from embodiment 1 in that the gap sensor 9 is omitted, and other configurations are substantially the same as embodiment 1. In this embodiment, the holding portion moving mechanism 8 for moving the lower holding portion 5b up and down, the pressure sensor 10, and the control portion 11 function as the interval narrowing mechanism 7 by further effectively using (using) the pressure sensor 10.

The same as in embodiment 1 is true except that the tire T is placed and held on the lower holding portion 5b as illustrated in fig. 14, and the upper shaft 2a and the lower shaft 2b are connected to each other via the coupler 4 to form one support shaft 2. A large up-down gap g exists between the upper holding portion 5a and the surface of the tire T (the peripheral portion of the upper bead portion Tb) facing the holding portion 5 a. Therefore, in this embodiment, the cooling medium C is injected from the injection unit 6 into the tire T, and the internal pressure Pi of the tire T is detected by the pressure sensor 10.

As illustrated in fig. 15, the lower holding portion 5b is moved upward together with the lower shaft 2b and the coupler 4 while the injection portion 6 injects the cooling medium C into the tire T and the pressure sensor 10 detects the internal pressure Pi, while the upper shaft 2a and the upper holding portion 5a are kept at a fixed position. The lower holding portion 5b is moved upward together with the lower shaft 2b and the coupler 4, and the vertical interval between the pair of upper and lower holding portions 5a, 5b is reduced until the internal pressure Pi detected by the pressure sensor 10 rises to a preset reference value. The vertical interval between the pair of upper and lower holding portions 5a, 5b when the internal pressure Pi becomes the reference value becomes the injection holding interval Di. The reference value may be a minimum internal pressure Pi within a range where a preliminary test or the like can be performed to ensure that the pair of upper and lower holding portions 5a, 5b are continuously and annularly abutted against the tire T in the circumferential direction.

By setting the vertical interval between the pair of upper and lower holding portions 5a, 5b to the injection holding interval Di, the pair of upper and lower holding portions 5a, 5b are respectively abutted against the tire T in a ring shape continuously in the circumferential direction. With this, the inner space of the tire T becomes a closed space surrounded by the tire T and the pair of upper and lower holding portions 5a, 5 b. Therefore, as in embodiment 1, the tire T can be smoothly inflated by the cooling medium C. In addition, as in embodiment 1, while the tire T is smoothly inflated by the cooling medium C injected into the tire T, the vertical interval between the pair of upper and lower holding portions 5a, 5b is widened from the injection holding interval Di to the preset reference interval Dc, and the tire T is maintained in the inflated state and cooled for a predetermined time.

Other embodiments (other PCI methods) using the same configuration as the embodiment of the PCI device 1 illustrated in fig. 14 to 15 will be described. In this embodiment, the holding portion moving mechanism 8 and the control portion 11 that move the lower holding portion 5b up and down function as the interval narrowing mechanism 7.

In this embodiment, for each specification of the tire T, a preliminary test or the like is performed to grasp in advance the actual value of the vertical interval Db of the bead portion Tb of the tire T immediately after the vulcanization of the tire T in the lateral direction. The injection holding interval Di is set to 80% to 95% of the actual value and input to the control unit 11.

In describing an example of the steps of the PCI process of this embodiment, the same as embodiment 1 is applied to a case where a tire T lying sideways is placed and held on a holding portion 5b on the lower side as illustrated in fig. 14, and an upper shaft 2a and a lower shaft 2b are connected to each other via a coupler 4 to form a single support shaft 2. A large up-down gap g exists between the upper holding portion 5a and the surface of the tire T (the peripheral portion of the upper bead portion Tb) facing the holding portion 5 a. Therefore, in the present embodiment, the vertical interval between the pair of upper and lower holding portions 5a, 5b is reduced so as to be set based on the actual value input to the control portion 11. In this embodiment, the cooling medium C is not injected into the tire T until the injection time maintaining interval Di is reached.

That is, as illustrated in fig. 15, the upper shaft 2a and the upper holding portion 5a are held at a fixed position in the vertical direction, and the lower holding portion 5b is moved upward together with the lower shaft 2b and the coupler 4, so that the vertical distance between the upper and lower pair of holding portions 5a and 5b becomes the injection holding distance Di. Since the injection holding interval Di is set to be slightly smaller than the actual value of the vertical interval Db of the vertical bead portion Tb of the tire T immediately after the horizontal vulcanization, the vertical interval of the pair of holding portions 5a, 5b is set to be the injection holding interval Di, and the pair of holding portions 5a, 5b are brought into contact with the tire T in a ring shape continuously in the circumferential direction. Accordingly, the inner space of the tire T becomes a closed space surrounded by the tire T and the pair of upper and lower holding portions 5a, 5b, and therefore, the tire T can be smoothly inflated by the cooling medium C as in embodiment 1. In addition, as in embodiment 1, while the tire T is inflated by the cooling medium C injected into the tire T, the vertical interval between the pair of upper and lower holding portions 5a, 5b is expanded from the injection-time holding interval Di to the preset reference interval Dc, and the tire T is maintained in the inflated state and cooled for a predetermined time.

If the injection holding interval Di exceeds 95% of the actual value, the pair of upper and lower holding portions 5a, 5b may not be brought into contact with the tire T continuously in the circumferential direction. On the other hand, if the injection holding interval Di is made smaller than 80% of the actual value, the tire T is cooled by the injected cooling medium C in a state of being excessively flattened up and down. Since the shape of the tire T at the time of initial cooling is easily reflected on the shape of the tire T after the completion of the PCI process, the injection holding interval Di is preferably set to 80% or more of the actual value described above in order to avoid unnecessary deformation of the tire T.

A description will be given of still another embodiment (another PCI method) using the same configuration as the embodiment of the PCI device 1 illustrated in fig. 14 to 15. In this embodiment, too, the holding portion moving mechanism 8 and the control portion 11 that move the lower holding portion 5b up and down function as the interval narrowing mechanism 7. In this embodiment, the injection holding interval Di is set to 20% to 60% of the reference interval Dc, and the control unit 11 is set.

In describing an example of the steps of the PCI process of this embodiment, the same as embodiment 1 is applied to a case where a tire T lying sideways is placed and held on a holding portion 5b on the lower side as illustrated in fig. 14, and an upper shaft 2a and a lower shaft 2b are connected to each other via a coupler 4 to form a single support shaft 2. A large up-down gap g exists between the upper holding portion 5a and the surface of the tire T (the peripheral portion of the upper bead portion Tb) facing the holding portion 5 a. Therefore, in the present embodiment, the vertical interval between the pair of upper and lower holding portions 5a and 5b is reduced so as to be set to the injection holding interval Di based on the reference interval Dc input to the control portion 11. In this embodiment, the cooling medium C is not injected into the tire T until the injection time maintaining interval Di is reached.

That is, as illustrated in fig. 15, the upper shaft 2a and the upper holding portion 5a are held at a fixed position in the vertical direction, and the lower holding portion 5b is moved upward together with the lower shaft 2b and the coupler 4, so that the vertical distance between the upper and lower pair of holding portions 5a and 5b becomes the injection holding distance Di. Since the injection holding interval Di is set to be very small relative to the reference interval Dc, the upper and lower intervals of the pair of upper and lower holding portions 5a, 5b are set to be the injection holding interval Di, and the pair of upper and lower holding portions 5a, 5b are brought into contact with the tire T in a ring shape continuously in the circumferential direction. With this, the inner space of the tire T becomes a closed space surrounded by the tire T and the pair of upper and lower holding portions 5a, 5 b. Therefore, as in embodiment 1, the tire T can be smoothly inflated by the cooling medium C. In addition, as in embodiment 1, while the tire T is inflated by the cooling medium C injected into the tire T, the vertical interval between the pair of upper and lower holding portions 5a, 5b is expanded from the injection-time holding interval Di to the preset reference interval Dc, and the tire T is maintained in the inflated state and cooled for a predetermined time.

If the injection holding interval Di exceeds 60% of the reference interval Dc, the pair of upper and lower holding portions 5a, 5b may not be brought into contact with the tire T in a circumferentially continuous annular shape. On the other hand, if the injection holding interval Di is made smaller than 20% of the reference interval Dc, the tire T is cooled by the injected cooling medium C in a state of being excessively flattened up and down. Since the shape of the tire T at the time of initial cooling is easily reflected on the shape of the tire T after the completion of the PCI process, the injection holding interval Di is preferably 20% or more, more preferably 40% or more of the actual value in order to avoid unnecessary deformation of the tire T.

The interval narrowing mechanism 7 used in the above-described respective embodiments may be applied in combination in a plurality of combinations within a range that can be combined. When the plural kinds of interval narrowing mechanisms 7 are applied in combination, the reduction of the vertical interval between the pair of upper and lower holding portions 5a, 5b may be stopped at the point in time when any one of the interval narrowing mechanisms 7 determines that the interval Di is maintained at the time of injection. In addition, in order to set the vertical interval between the pair of upper and lower holding portions 5a, 5b to the injection holding interval Di, it is also possible to set the specification to move only either one of the pair of upper and lower holding portions 5a, 5b vertically, but the specification to move the pair of upper and lower holding portions 5a, 5b vertically independently of each other has the advantage that the vertical movement amount of each holding portion 5a, 5b can be reduced.

The present disclosure includes the following inventions.

[ Invention 1]

A tire secondary vulcanization expansion method, wherein a tire is maintained in an expanded state by holding upper and lower bead portions of a tire immediately after vulcanization by a pair of upper and lower holding portions and injecting a cooling medium into the tire,

The tire is inflated by the cooling medium while expanding the tire by the pair of upper and lower holding portions, by setting the upper and lower intervals of the pair of upper and lower holding portions to injection holding intervals smaller than the upper and lower intervals of the bead portions of the tire immediately after horizontal vulcanization, so that the tire is maintained in an inflated state while expanding the upper and lower intervals of the pair of upper and lower holding portions from the injection holding intervals to a preset reference interval.

[ Invention 2]

According to the tire secondary vulcanization expansion method of the invention [1], the tire is placed and held on the holding portion on the lower side, the vertical gap between the upper holding portion and the surface of the tire facing the holding portion is detected by the sensor, and the vertical gap between the pair of holding portions is reduced until the detected vertical gap becomes zero, so that the vertical gap between the pair of holding portions becomes the injection holding gap.

[ Invention 3]

According to the tire secondary vulcanization expansion method of the invention 1 or 2, the tire is placed and held on the holding portion on the lower side, the outflow pressure of the cooling medium flowing out from the inside of the tire through the upper and lower gaps of the surface of the holding portion on the upper side opposite to the holding portion is detected by the sensor, and the upper and lower gap between the pair of holding portions is reduced until the detected outflow pressure becomes zero, so that the upper and lower gap between the pair of holding portions becomes the injection holding gap.

[ Invention 4]

The method for secondary vulcanization expansion of a tire according to any one of inventions 1 to 3, wherein the tire is placed and held on the lower side of the holding portion, the contact pressure between the upper side of the holding portion and the surface of the tire facing the holding portion is detected by a sensor, and the vertical interval between the pair of holding portions is reduced until the detected contact pressure rises to a preset reference value, so that the vertical interval between the pair of holding portions becomes the injection-time holding interval.

[ Invention 5]

The method for secondary vulcanization expansion of a tire according to any one of inventions 1 to 4, wherein the tire is placed and held on the holding portion on the lower side, the internal pressure of the tire is detected by the sensor while the cooling medium is injected into the tire, and the vertical interval between the pair of holding portions is reduced until the detected internal pressure rises to a preset reference value, so that the vertical interval between the pair of holding portions becomes the injection-time holding interval.

[ Invention 6]

The method for secondary vulcanization expansion of a tire according to any one of inventions 1 to 5, wherein an actual value of an up-down gap between the bead portions of the tire immediately after horizontal vulcanization is grasped in advance for each specification of the tire, and the injection-time holding gap is set to 80% to 95% of the actual value.

[ Invention 7]

The method for secondary vulcanization expansion of a tire according to any one of the inventions [ 1] to [ 5], wherein the injection holding interval is set to 20% to 60% of the reference interval.

[ Invention 8]

The method for secondary vulcanization expansion of a tire according to any one of the inventions 1 to 7, wherein the pair of upper and lower holding portions are moved up and down independently of each other, whereby the upper and lower intervals between the pair of upper and lower holding portions are set to the injection-time holding interval.

[ Invention 9]

A tire secondary vulcanization expansion device is provided with: a pair of upper and lower holding portions that hold upper and lower bead portions of a tire immediately after vulcanization, which is laid sideways; and an injection unit that injects a cooling medium into the tire, wherein the tire secondary vulcanization expansion device maintains the tire in an expanded state by the cooling medium,

The tire secondary vulcanization expansion device includes a gap narrowing mechanism for reducing the vertical gap between the upper and lower bead portions of the tire immediately after horizontal vulcanization, wherein the gap narrowing mechanism expands the vertical gap between the upper and lower pair of holding portions from the injection holding gap to a preset reference gap and maintains the tire in an expanded state by making the vertical gap between the upper and lower pair of holding portions smaller than the vertical gap between the upper and lower bead portions of the tire immediately after horizontal vulcanization.

Claims

1. A tire secondary vulcanization expansion method, wherein a tire is maintained in an expanded state by holding upper and lower bead portions of a tire immediately after vulcanization by a pair of upper and lower holding portions and injecting a cooling medium into the tire,

2. The method for secondary vulcanization expansion of a tire according to claim 1,

And a holding unit for placing and holding the tire on the lower side, wherein a vertical gap between the upper side holding unit and a surface of the tire facing the holding unit is detected by a sensor, and a vertical gap between the pair of holding units is reduced until the detected vertical gap becomes zero, so that the vertical gap between the pair of holding units becomes the injection holding gap.

3. The method for secondary vulcanization expansion of a tire according to claim 1,

The tire is placed and held on the lower holding portion, the vertical gap between the upper holding portion and the surface of the tire facing the holding portion is detected by a sensor, and the outflow pressure of the cooling medium flowing out from the inside of the tire to the outside is reduced until the detected outflow pressure becomes zero, so that the vertical gap between the upper and lower holding portions becomes the injection holding gap.

4. The method for secondary vulcanization expansion of a tire according to claim 1,

The tire is placed on the lower holding portion and held by the lateral holding portion, a contact pressure between the upper holding portion and a surface of the tire facing the upper holding portion is detected by a sensor, and the vertical interval between the upper and lower holding portions is reduced until the detected contact pressure rises to a preset reference value, so that the vertical interval between the upper and lower holding portions becomes the injection holding interval.

5. The method for secondary vulcanization expansion of a tire according to claim 1,

The tire is placed on the lower holding portion and held by the tire while the cooling medium is injected into the tire, and the vertical interval between the pair of upper and lower holding portions is reduced by detecting the internal pressure of the tire by a sensor until the detected internal pressure rises to a preset reference value, so that the vertical interval between the pair of upper and lower holding portions becomes the injection-time holding interval.

6. The method for secondary vulcanization expansion of a tire according to claim 1,

For each specification of the tire, an actual value of an up-down gap between the bead portions of the tire immediately after the tire is vulcanized in a horizontal direction is grasped in advance, and the injection holding gap is set to 80% to 95% of the actual value.

7. The method for secondary vulcanization expansion of a tire according to claim 1,

The injection holding interval is set to 20% to 60% of the reference interval.

8. The method for secondary vulcanization expansion of a tire according to any one of claims 1 to 7,

The pair of holding portions are moved up and down independently of each other, so that the vertical distance between the pair of holding portions becomes the injection holding distance.

9. A tire secondary vulcanization expansion device is provided with: a pair of upper and lower holding portions that hold upper and lower bead portions of a tire immediately after vulcanization, which is laid sideways; and an injection unit that injects a cooling medium into the tire, wherein the tire secondary vulcanization expansion device maintains the tire in an expanded state by the cooling medium,

The tire secondary vulcanization expansion device is configured to include a gap narrowing mechanism for reducing the vertical gap between the upper and lower bead portions of the tire immediately after horizontal vulcanization, wherein the gap narrowing mechanism is configured to expand the vertical gap between the upper and lower pair of holding portions from the injection holding gap to a preset reference gap and maintain the tire in an expanded state while the tire is inflated by the cooling medium, by making the vertical gap between the upper and lower pair of holding portions smaller than the injection holding gap between the upper and lower bead portions of the tire immediately after horizontal vulcanization.