JP2021181172A - Manufacturing method and manufacturing apparatus of pneumatic tire - Google Patents

Abstract

To improve tire quality.SOLUTION: A manufacturing method of a pneumatic tire includes the steps of: initially expanding a bladder 10 in a tire lumen of a green tire T placed outside a vulcanization die 2 S2; setting the green tire T in the vulcanization die 2 together with the initially expanded bladder 10 S5; and after closing the vulcanization die 2, further expanding the initially expanded bladder 10 to press the green tire T against the vulcanization die 2 S6.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a pneumatic tire and a manufacturing apparatus thereof.

The following Patent Document 1 describes a tire vulcanizer for vulcanizing raw tires and a method for vulcanizing raw tires using this tire vulcanizer. The tire vulcanizer is an upper mold arranged at a tire vulcanization position, a lower mold provided with a bladder, and a moving device for moving the lower mold between a tire supply position and a tire vulcanization position. , And a tire supply device for supplying the raw tire to the lower mold. Then, as the vulcanization method, first, the raw tire held in the tire supply device is mounted on the lower mold arranged at the tire supply position. Next, the tire supply device is removed from the raw tire. Then, the raw tire and the lower mold are moved to the tire vulcanization position by the moving device and set in the upper mold. Finally, the bladder of the lower mold is expanded and the raw tire is vulcanized.

Japanese Unexamined Patent Publication No. 2004-122407

In order to vulcanize and mold the tire accurately, it is necessary to properly inflate the bladder. However, unexpected expansion of the bladder may occur due to misalignment between the bladder and the raw tire, expansion of the bladder without completely spreading wrinkles when the bladder is folded, and the like. In such a case, in the vulcanized tire, wrinkles of the bladder may be formed on the inner surface of the tire, rubber may protrude from the bead toe portion (L / TO), and uniformity may be deteriorated. There was a problem that the quality of the tire deteriorated.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a pneumatic tire capable of improving tire quality and a manufacturing apparatus thereof.

The present invention is a method for manufacturing a pneumatic tire, wherein a bladder is inserted through a bead opening of a raw tire placed outside the vulcanization mold, and the bladder is initially expanded in the tire cavity. The step of setting the raw tire together with the initially expanded bladder in the vulcanization mold, and after closing the vulcanization mold, the initially expanded bladder is further expanded to add the raw tire. Includes the step of pressing against the vulcanization mold.

It is desirable that the method for manufacturing a pneumatic tire according to the present invention includes a step of holding the raw tire with a loader, and the holding step is performed prior to the initial expansion step.

It is desirable that the method for manufacturing a pneumatic tire according to the present invention includes a step of removing the loader from the raw tire, and the removing step is performed prior to the setting step.

The method for manufacturing a pneumatic tire according to the present invention includes a step of controlling the expansion amount of the bladder that is initially expanded in the tire cavity, and the controlling step is performed prior to the removing step. Is desirable.

In the method for manufacturing a pneumatic tire according to the present invention, it is desirable that the control step includes a step of measuring the expansion amount of the bladder.

In the method for manufacturing a pneumatic tire according to the present invention, it is desirable that the control step includes a step of adjusting the expansion state of the bladder.

The present invention is an apparatus for manufacturing a pneumatic tire, which includes a lower mold, an upper mold located apart from the lower mold, a moving tool, and a control tool, and the lower mold is a sideways raw tire. The mover has a molded surface that holds the tire from below and a bladder that can expand in the cavity of the raw tire through the bead opening of the raw tire placed on the molded surface. The lower mold or the upper mold is moved so that the lower mold and the upper mold come into contact with each other to form a vulcanization space for the raw tire, and the control tool is the lower mold by the moving tool. Alternatively, prior to the movement of the upper mold, the bladder is initially inflated in the tire cavity of the raw tire placed on the lower mold.

It is desirable that the pneumatic tire manufacturing apparatus according to the present invention further includes a loader for holding the green tire in a sideways direction from above.

It is desirable that the device for manufacturing a pneumatic tire according to the present invention includes a measuring tool for measuring the expansion amount of the raw tire in which the loader is initially inflated.

In the pneumatic tire manufacturing apparatus according to the present invention, it is desirable that the measuring tool is a non-contact type displacement meter.

The tire quality can be improved by adopting the above-mentioned configuration in the method for manufacturing a pneumatic tire and the manufacturing apparatus thereof of the present invention.

It is sectional drawing which shows typically the manufacturing apparatus used in the manufacturing method of the pneumatic tire of this invention. (A) is a flowchart of the present embodiment, (b) is a flowchart of the holding process of (a), and (c) is a flowchart of the control process of (a). It is sectional drawing of the manufacturing apparatus which schematically shows the 2nd holding process of this embodiment. It is sectional drawing of the manufacturing apparatus which shows typically the initial expansion process of this embodiment. It is sectional drawing of the vulcanization apparatus which shows typically the removal process of this embodiment. It is sectional drawing of the manufacturing apparatus which shows typically the setting process and the pressing process of this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The method for manufacturing a pneumatic tire of the present invention (hereinafter, may be simply referred to as "manufacturing method") includes a step of forming a raw tire T (shown in FIG. 1) and vulcanization of the formed raw tire T. Includes vulcanization process. Since a well-known method is adopted for the step of forming the raw tire T (hereinafter, may be simply referred to as “raw tire forming step”), detailed description thereof will be omitted.

FIG. 1 is a cross-sectional view conceptually illustrating an embodiment of a pneumatic tire manufacturing apparatus (hereinafter, may be simply referred to as “manufacturing apparatus”) 1 used in the vulcanization step of the present embodiment. The manufacturing apparatus 1 of the present embodiment includes a vulcanization die 2, a moving tool 3, and a controlling tool 4. Further, the manufacturing apparatus 1 may include, for example, a loader 5.

In the present embodiment, the raw tire T moves sideways in the manufacturing apparatus 1 and is set in the vulcanization die 2. In the present specification, the above-mentioned "horizontal direction" means a direction in which the tire axial direction of the raw tire T is vertical. As a result, as shown in FIG. 1, the lateral raw tire T is divided into a first portion T1, a second portion T2, and a third portion T3. The first portion T1 is, for example, a portion outside the tire radial direction from the maximum width position (not shown) of the tire after vulcanization. The second portion T2 is, for example, a portion arranged above the first portion T1 on the inner side in the radial direction of the tire. The third portion T3 is, for example, a portion arranged inside the tire radial direction with respect to the first portion T1 and below the second portion T2. Further, the raw tire T includes an upper bead opening T4 formed inside the tire radial direction of the second portion T2 and a lower bead opening T5 formed inside the tire radial direction of the third portion T3. I'm out. The upper bead opening T4 and the lower bead opening T5 include the tire rotation shaft Tc of the raw tire T. In the figure, the vertical direction is indicated by the arrow Z.

The vulcanization die 2 of the present embodiment includes a lower die 7 and an upper die 8 located apart from the lower die 7. In the present embodiment, the lower mold 7 and the upper mold 8 are in contact with each other (shown in FIG. 6). The lower mold 7 and the upper mold 8 come into contact with each other to form a vulcanization space K for vulcanizing the raw tire T. As used herein, the term "contact" means that two objects that can be separated come into contact with each other.

In the present embodiment, the lower mold 7 is a molded surface (hereinafter, may be referred to as “lower molded surface”) 9 that holds the sideways raw tire T from below, and the raw tire T placed on the molded surface 9. It has a bladder 10 that can be expanded in the tire lumen (hereinafter, may be simply referred to as "intra-lumen"). The bladder 10 is made of a well-known elastic material such as rubber.

Further, the lower mold 7 has, for example, a bagwell 11 having a well-known structure for accommodating the bladder 10. The bagwell 11 of the present embodiment is connected to a supply line (not shown) for supplying a pressure medium made of a well-known high-pressure fluid such as steam or an inert gas. The pressure medium is supplied to the bagwell 11 to inflate the bladder 10.

The lower mold 7 includes, for example, a lower segment 12 forming the lower forming surface 9 and a lower plate 13 arranged below the lower segment 12. The lower segment 12 contains, for example, a heating tool (not shown) for vulcanizing the third portion T3 of the raw tire T. The lower segment 12 and the lower plate 13 have, for example, an opening for holding the bagwell 11. In this embodiment, the lower plate 13 is fixed to the lower base plate 14. As described above, the lower mold 7 of the present embodiment has a well-known structure.

The upper mold 8 of the present embodiment is arranged above the lower mold 7. The upper mold 8 includes, for example, a molded surface (hereinafter, may be referred to as “upper molded surface”) 16 that covers the sideways raw tire T from above and from the side. The upper mold 8 includes, for example, a separable upper segment 17 forming the upper forming surface 16 and an upper plate 18 arranged above the upper segment 17. The upper segment 17 includes, for example, a heating tool (not shown) for heating the first portion T1 and the second portion T2 of the raw tire T. The upper plate 18 is held, for example, by a first moving tool 20 described later so as to be movable up and down. As described above, the upper mold 8 of the present embodiment has a well-known structure.

The moving tool 3 of the present embodiment is for moving the lower mold 7 or the upper mold 8 so as to form the vulcanization space K of the raw tire T. The moving tool 3 of the present embodiment includes a first moving tool 20 for moving the upper mold 8 and a second moving tool 21 for moving the lower mold 7. The moving tool 3 is not limited to such an embodiment, and may be composed of, for example, only the first moving tool 20.

The first moving tool 20 of the present embodiment moves the upper mold 8 up and down (vertically). In the present embodiment, the first moving tool 20 includes a support shaft 20a that holds the upper plate 18 and moves it up and down. Such a first moving tool 20 is formed of a well-known structure such as a ball screw or a telescopic cylinder structure.

The second moving tool 21 of the present embodiment moves the lower mold 7 in the horizontal direction. The second moving tool 21 moves the lower base plate 14 linearly toward a position below the upper mold 8 (hereinafter, may be referred to as “vulcanization position A”). Such a second moving tool 21 is formed of a well-known structure such as a ball screw or a telescopic cylinder structure.

The loader 5 of the present embodiment has a function of moving the raw tire T formed in the raw tire forming step and mounting it on the lower mold 7. The loader 5 is composed of, for example, a horizontal substrate 24 and a plurality of arm portions 25 protruding downward from the substrate 24. In the present embodiment, the substrate 24 is movably held in three dimensions by a moving tool having a well-known structure (not shown). The arm portion 25 has, for example, a bead holder 25a having a well-known structure for holding the second portion T2. In this embodiment, the arm portion 25 holds the second portion T2 from the upper bead opening T4. As described above, the loader 5 of the present embodiment can suspend and move the raw tire T. The loader 5 is not limited to such an embodiment, and has, for example, a holder (not shown) having a well-known structure for holding the raw tire T on the molding surface 9 of the lower mold 7. May be good.

Further, in the present embodiment, the loader 5 has a measuring tool 27 for measuring the expansion amount of the bladder 10 that expands in the tire lumen (in the present embodiment, the initial expansion amount described later). The measuring tool 27 is fixed to the substrate 24, for example. In the present embodiment, the measuring tool 27 is preferably a non-contact type displacement meter. As the measuring tool 27, for example, a laser displacement meter that measures a distance by irradiating a measurement object with a laser is more desirable. Such a measuring tool 27 can output, for example, measurement data d regarding a distance to a measurement object as an electric signal.

The controller 4 is configured as, for example, a computer. The controller 4 is, for example, a memory for storing measurement data d and the like, a CPU (Central Processing Unit) for executing various arithmetic processes and information processing, a storage device such as a magnetic disk, and a display for displaying processing results. It has a unit, an operation unit for operating the measuring tool 27, and the like. For example, a program or the like is stored in advance in the storage device. In the present embodiment, the program has a function of initially inflating the bladder 10 in the tire lumen of the raw tire T placed in the lower mold 7 prior to the movement of the lower mold 7 or the upper mold 8 by the moving tool 3. doing. The program may have, for example, a function of controlling the expansion amount of the bladder 10 and a function of controlling the heating amount of the vulcanization die 2. The measuring tool 27 may have a function of controlling the expansion amount of the bladder 10.

Next, the vulcanization step of the manufacturing method using such a manufacturing apparatus 1 will be described. FIG. 2A is a flowchart of the vulcanization process. As shown in FIG. 2A, the vulcanization step of the present embodiment includes an initial expansion step S2, a setting step S5, and a pressing step S6. Further, the vulcanization step includes, for example, a holding step S1, a control step S3, and a removal step S4.

FIG. 2B is a flowchart of the holding step S1. As shown in FIG. 2B, in the holding step S1 of the present embodiment, the first holding step S1a in which the raw tire T is held by the loader 5 and the raw tire T held by the loader 5 are further reduced to the lower mold 7. Includes a second holding step S1b for holding in. FIG. 1 shows a first holding step S1a.

As shown in FIG. 1, in the first holding step S1a, in the present embodiment, the bead holder 25a of the loader 5 holds the second portion T2 of the raw tire T. As a result, the raw tire T is held by the loader 5 in a suspended state and can be moved three-dimensionally.

Next, the second holding step S1b is performed. FIG. 3 is a cross-sectional view illustrating the second holding step S1b. As shown in FIG. 3, in the second holding step S1b of the present embodiment, the lower mold 7 may be separated from the upper mold 8 in the horizontal direction (hereinafter, referred to as “raw tire receiving position B”). ) Is moved by the second moving tool 21. Then, in the second holding step S1b, the raw tire T held by the loader 5 is moved to the raw tire receiving position B. Then, for example, the loader 5 is lowered, and the third portion T3 of the raw tire T is held on the lower molded surface 9. As a result, the raw tire T is held by the loader 5 and the lower mold 7 in the present embodiment.

Next, the initial expansion step S2 is performed. FIG. 4 is a cross-sectional view illustrating the initial expansion step S2. As shown in FIG. 4, in the initial expansion step S2, first, a pressurizing medium is supplied into the bagwell 11 from the supply line (not shown), and a bladder 10 is inserted from the lower bead opening T5 in the tire lumen. Inflate. In the initial expansion step S2, the raw tire T is visible. Therefore, even if the raw tire T is displaced due to the expansion of the bladder 10, it can be easily repositioned at an appropriate position. In addition, such expected expansion can eliminate wrinkles and the like caused by accommodating the bladder 10 in the bagwell 11. Thereby, for example, the unexpected expansion of the bladder 10 that occurs in the vulcanization die 2 can be suppressed. Therefore, the manufacturing method of the present embodiment can improve the tire quality. It is desirable that the pressure P1 of the pressurizing medium in such an initial expansion step S2 is, for example, 30 KPa or less.

Next, the control step S3 is performed. FIG. 2C is a flowchart of the control step S3. As shown in FIG. 2C, the control step S3 of the present embodiment includes a step S3a for measuring the expansion amount of the bladder 10 and a step S3b for adjusting the expansion state of the bladder 10.

As shown in FIG. 4, in the measurement step S3a, in the present embodiment, the expansion amount X of the bladder 10 initially expanded in the raw tire T is measured. In the measuring step S3a of the present embodiment, the expansion amount X is measured by the measuring tool 27. The expansion amount X is measured, for example, as a vertical distance between the substrate 24 and the bladder 10 exposed from the upper bead opening T4. When a laser displacement meter is adopted as the measuring tool 27, for example, the measurement data d regarding the measured expansion amount X is converted into an electric signal and output to the control tool 4.

It is desirable that the expansion amount X is measured, for example, at a plurality of predetermined positions of the bladder 10. It is desirable that the expansion amount X is measured including, for example, a position on the tire rotation axis Tc. The expansion amount X may be measured, for example, at equal pitches in the circumferential direction of the raw tire T with the tire rotation axis Tc as the center.

The adjusting step S3b adjusts the expanded state of the bladder 10 based on, for example, the measured expansion amount X. In the adjustment step S3b, in the present embodiment, the controller 4 controls the supply amount of the pressurizing medium by an on-off valve or the like (not shown) provided in the supply line, and the expansion amount X becomes a predetermined range. As described above, the expansion amount of the bladder 10 is adjusted. This allows the bladder 10 to be evenly initially expanded into the lumen of the raw tire T. Further, the raw tire T can be positioned appropriately with respect to the molding surface 9.

Next, the removal step S4 is performed. FIG. 5 is a cross-sectional view illustrating the removal step S4. As shown in FIG. 5, in the removal step S4 of the present embodiment, the loader 5 is removed from the raw tire T. In this removal step S4, the state in which the lower mold 7 holds the raw tire T is maintained, and the initial expansion of the bladder 10 is maintained. In the removal step S4, the loader 5 is separated from the raw tire receiving position B in order to receive, for example, a new raw tire (not shown) formed in the raw tire forming step. In the removal step S4, for example, the second moving tool 21 is driven to move the lower mold 7 and the raw tire T from the raw tire receiving position B to the vulcanization position A. At this time, since the raw tire T is held by the initially expanded bladder 10, the displacement from the lower mold 7 due to this movement is suppressed.

Next, the setting step S5 is performed. FIG. 6 is a cross-sectional view illustrating the setting process S5 and the pressing process S6. As shown in FIG. 6, in the setting step S5 of the present embodiment, the raw tire T is set in the vulcanization die 2 together with the initially expanded bladder 10. In the setting step S5, for example, the upper die 8 is lowered by the first moving tool 20, and the raw tire T is set in the vulcanization space K between the upper die 8 and the lower die 7. In the setting step S5 of the present embodiment, the lower segment 12 and the upper segment 17 come into contact with each other to form a closed vulcanization space K.

Next, the pressing step S6 is performed. In the pressing step S6 of the present embodiment, the initially expanded bladder 10 is further expanded to press the raw tire T against the vulcanization die 2. Then, the vulcanization die 2 is heated by the heating tool (not shown) to vulcanize the raw tire T. The pressure P2 of the pressurizing medium in the pressing step S6 is preferably 1.0 MPa or more, preferably 2.0 MPa or less, and 1.5 MPa or more when the pressurizing medium is nitrogen gas, for example, when the pressurizing medium is steam. Is desirable, and 2.5 MPa or less is desirable.

Although the particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment and can be modified into various embodiments.

Raw tires were vulcanized using the manufacturing apparatus having the basic structure shown in FIG. 1, and tire quality tests were conducted on the vulcanized tires (hereinafter referred to as “vulcanized tires”). Tire quality was confirmed by appearance test, uniformity test and dynamic balance test. In the comparative example, the raw tire was vulcanized in the same manner as in the embodiment except that the initial expansion step and the control step of the present embodiment were not performed. In both the examples and comparative examples, 5000 raw tires were used, and the average value was calculated in each test.

<Appearance test>
The state of wrinkles caused by the bladder adhering to the lumen surface of the vulcanized tire was visually confirmed by the tester. The results are indicated by the ratio of the number of wrinkled tires. The smaller the number, the better.

<Uniformity test>
RFV (radial force variation) and LFV (lateral force variation) were measured using a uniformity tester in accordance with JASO C607 (Uniformity test method for automobile tires). The result is shown by an exponent with a comparative example of 100. The smaller the number, the better.

<Dynamic balance test>
The dynamic balance was measured using a dynamic balance tester. The result is shown by an exponent with a comparative example of 100. The smaller the number, the better. The test results are shown in Table 1.

It can be understood that the vulcanization method of the example is superior in tire quality to the vulcanization method of the comparative example.

2 Vulcanization die 10 Bladder S2 Initial expansion process S5 Setting process S6 Pressing process T Raw tire

Claims (10)

It ’s a method of manufacturing pneumatic tires.
A process of inserting a bladder through the bead opening of a raw tire placed outside the vulcanization die and initially expanding the bladder in the tire lumen.
The step of setting the raw tire in the vulcanization die together with the initially expanded bladder,
After closing the vulcanization die, the step of further expanding the initially expanded bladder and pressing the raw tire against the vulcanization die is included.
How to make a pneumatic tire. Including the step of holding the raw tire with a loader.
The method for manufacturing a pneumatic tire according to claim 1, wherein the holding step is performed prior to the initial expansion step. Including the step of removing the loader from the raw tire.
The method for manufacturing a pneumatic tire according to claim 2, wherein the removing step is performed prior to the setting step. A step of controlling the amount of expansion of the bladder that is initially inflated in the tire lumen is included.
The method for manufacturing a pneumatic tire according to any one of claims 1 to 3, wherein the controlling step is performed prior to the removing step. The method for manufacturing a pneumatic tire according to claim 4, wherein the controlling step includes a step of measuring the expansion amount of the bladder. The method for manufacturing a pneumatic tire according to claim 4 or 5, wherein the controlling step includes a step of adjusting the expansion state of the bladder. It is a manufacturing device for pneumatic tires.
The lower mold, the upper mold located apart from the lower mold, the moving tool, and the control tool are included.
The lower mold has a molded surface that holds the sideways raw tire from below, and a bladder that can expand in the lumen of the raw tire through the bead opening of the raw tire placed on the molded surface. Have and
The moving tool moves the lower mold or the upper mold so that the lower mold and the upper mold come into contact with each other to form a vulcanization space for the raw tire.
The controller initially inflates the bladder in the tire lumen of the raw tire placed in the lower mold prior to the movement of the lower or upper mold by the mover.
Pneumatic tire manufacturing equipment. The pneumatic tire manufacturing apparatus according to claim 7, further comprising a loader for holding the raw tire in a sideways direction from above. The pneumatic tire manufacturing apparatus according to claim 7, wherein the loader includes a measuring tool for measuring the expansion amount of the initially expanded raw tire. The pneumatic tire manufacturing apparatus according to claim 9, wherein the measuring tool is a non-contact type displacement meter.

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