JP2020097136A - Manufacturing method of side wall rubber - Google Patents

Abstract

To surely provide a through-hole while conveying side wall rubber, by making a thickness of the side wall rubber be appropriate.SOLUTION: A manufacturing method of side wall rubber 30 comprises: an extrusion step of extruding the side wall rubber 30 constituting a side wall part 3 of a tire 1 from an extruder 5; a conveyance step of conveying the side wall rubber 30; a winding step of winding the side wall rubber 30 in a roll form; and a hole-boring step of boring a plurality of through-holes 31 . . . 31 in the side wall rubber 30 in the conveyance step. In the conveyance step, the side wall rubber 30 is continuously conveyed. In the hole-boring step, holes are opened by winding the side wall rubber 30 around a roller 72 provided with needles, for which the needles are provided on a peripheral surface provided on a conveyance path in the conveyance step. In the hole-boring step, the holes are opened in a state where a predetermined tension is applied to the side wall rubber 30.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing a sidewall rubber of a tire.

As a pneumatic tire, each tire constituent member such as inner liner, carcass ply, sidewall portion, bead portion, tread portion, etc. is formed in advance, and these tire constituent members are bonded in an unvulcanized state to form a green tire. However, those manufactured by vulcanizing and molding this green tire are known.

Air may be trapped between the rubber members of the green tire during molding of the green tire. For example, if air remains between the carcass ply and the sidewall rubber in the sidewall portion, a bare tire (chip) is likely to occur in the sidewall portion of the manufactured pneumatic tire.

Therefore, after molding the green tire, a hole may be formed in the sidewall rubber by using a cone, and air between the carcass ply and the sidewall rubber may be discharged from the hole. However, when a hole is formed in the sidewall rubber from the outside (profile surface) by using a cone, the hole on the outer side of the tire is formed larger than the hole on the inner side, and the rubber flow during vulcanization tends to deteriorate.

Patent Document 1 discloses a method for manufacturing a rubber member and a pneumatic tire in which a sidewall rubber before being attached to a carcass ply is provided with a through hole penetrating from an inner surface side to a carcass attachment side to an outer surface side (profile surface side). It is disclosed.

By the way, the sidewall rubber has low rigidity and is easily bent as compared with a carcass ply containing a cord or the like. Therefore, the sidewall rubber may be bent at the time of drilling, and the through hole may not be reliably formed. In order to increase the rigidity of the sidewall rubber itself, it is possible to increase the thickness of the sidewall rubber. However, the weight is unnecessarily increased, which is not preferable from the viewpoint of cost and fuel consumption.

On the other hand, in Patent Document 2, the sidewall rubber before being attached to the carcass ply is placed on the placing table, and the needle is moved up and down from above the placing table, whereby the sidewall having low rigidity is obtained. A sidewall hauling device and a hauling method for forming a through hole in rubber are disclosed.

JP, 2006-0888586, A JP, 2017-177556, A

In the holing device of Patent Document 2, since the sidewall rubber is placed on the mounting table to make holes, it is necessary to provide a process different from the process from the extrusion process to the molding process. Even if it is possible to provide a hole punching step during the step, it is necessary to stop the conveyance of the sidewall rubber when punching the sidewall rubber. That is, there is room for improvement in order to carry out perforation while conveying the sidewall rubber while making the thickness of the sidewall rubber appropriate.

An object of the present invention, as a method for manufacturing a sidewall rubber, is to reliably provide a through hole while conveying the sidewall rubber while suppressing an increase in the thickness of the sidewall rubber.

The present invention includes an extrusion step of extruding a rubber member constituting a sidewall portion of a tire from an extruder, a conveying step of conveying the rubber member, a winding step of winding the rubber member into a roll, and the conveying step. A step of boring a plurality of through holes in the rubber member therein, the conveying step continuously conveys the rubber member, and the hole forming step is on a conveying path of the conveying step. To make a hole by winding the rubber member around the needle roller provided with a needle on the peripheral surface provided in, in the hole making step, make a hole in a state in which a predetermined tension is applied to the rubber member, A method for manufacturing a sidewall rubber is provided.

According to the present invention, when a through hole for venting air is formed in a rubber member that constitutes a sidewall portion, by applying a predetermined tension to the rubber member, for example, as compared with a carcass ply or the like. It is possible to surely make a hole in the rubber member without unnecessarily increasing the thickness of the rubber member of the sidewall portion having low rigidity. Thereby, the air between the rubber member and the carcass ply can be discharged from the plurality of through holes of the rubber member of the sidewall portion formed with the optimum thickness. As a result, the performance and quality of the pneumatic tire can be secured.

Further, a plurality of through holes can be provided in the rubber member while the rubber member is being conveyed by the needle roller provided in the conveying step. According to this, for example, during the conveying process in which the rubber member is extruded from the extruder and then wound up by the winding device, the rubber member is efficiently conveyed without stopping (without reducing the process speed). Opening can be performed.

Preferably, the method further includes a tension changing step of changing the tension applied to the rubber member in the punching step.

Since the optimum tension of the rubber member varies depending on the hardness and the thickness, for example, if the tension required for punching the rubber member is insufficient, the needle may bend the rubber member and a defect such that a through hole is not formed may occur. ..
According to this configuration, the through hole can be surely provided by applying the optimum tension to the rubber member. For example, a rubber member having a high hardness and a rubber member having a large thickness are given a higher tension, so that the rubber member can be reliably drilled.

Further, preferably, in the punching step, the needle of the needle roller is allowed to project radially outward from the outer peripheral surface of the needle roller and is radially inner from the outer peripheral surface of the needle roller. It is possible to evacuate to.

According to this configuration, since the needle of the needle roller is provided so as to project and retract from the outer peripheral surface of the needle roller, the needle can be retracted after forming the through hole. As a result, the needle is conveyed while penetrating the rubber member, as in the case where the needle is always protruding from the outer peripheral surface of the needle roller, so that the shape of the through hole unnecessarily conveys the rubber member. Expansion (extension) in the direction (longitudinal direction) is suppressed.

Further, preferably, in the boring step, a hole having a larger diameter is formed on a surface to be adhered, which is adhered to a carcass ply forming the skeleton of the tire of the rubber member, than on a surface opposite to the surface to be adhered.

According to this configuration, during vulcanization molding, it is possible to suppress deterioration of rubber flow from the surface to be adhered to the carcass ply of the rubber member to the side opposite to the surface to be adhered.

Further, preferably, in the carrying step, the needle roller is provided as a carrying device.

According to this configuration, since the roller with the needle has the conveying function, it is possible to make a hole in the rubber member while maintaining the process speed.

Further, preferably, after the winding step, there is further included a molding step of molding a green tire.

According to this configuration, it is possible to monitor only the rubber member of the sidewall portion by making holes for venting air in the process of manufacturing only the rubber member of the sidewall portion. As a result, for example, it is possible to more surely reduce the quality defects of the rubber member of the sidewall portion, as compared with the case where the punching is performed in the step of combining with other members such as the molding step.

In addition, when quality defects occur, it is possible to respond by simply stopping only the minimum line, so if you make holes in a process that is combined with other members such as the molding process, stop the entire tire manufacturing line. However, it can be dealt with by stopping only the step of manufacturing the rubber member of the sidewall portion.

In the method for manufacturing a sidewall rubber according to the present invention, it is possible to surely form the through hole while conveying the sidewall rubber while suppressing an increase in the thickness of the sidewall rubber.

Sectional drawing of the pneumatic tire formed by embodiment of this invention. Explanatory drawing of the manufacturing line of the sidewall rubber in this embodiment. The schematic diagram which shows the roller with a needle in the accommodated state of a needle member. The schematic diagram which shows the roller with a needle in the protruding state of a needle member. FIG. 3 is a development view schematically showing the arrangement of needle members of a roller with needles. Sectional drawing which shows the shape of the through-hole of a sidewall rubber. The graph which shows the tendency of the tension with respect to the thickness of sidewall rubber. The graph which shows the tendency of the tension with respect to the hardness of sidewall rubber.

Embodiments according to the present invention will be described below with reference to the accompanying drawings. Note that the following description is merely an example in essence, and is not intended to limit the present invention, its application, or its application. Also, the drawings are schematic, and the ratios of the respective dimensions are different from the actual ones.

The present invention relates to a method of manufacturing a sidewall rubber as a rubber member forming a sidewall portion of a pneumatic tire 1. Prior to the description of the method for producing the sidewall rubber, the outline of the configuration of the pneumatic tire 1 including the sidewall rubber will be described with reference to FIG.

FIG. 1 is a half sectional view in the meridian direction of the pneumatic tire 1 according to this embodiment, showing only one side with respect to the tire equator line. As shown in FIG. 1, a pneumatic tire 1 includes a tread portion 2 having a tread surface, a pair of sidewall portions 3 connected to both end portions on the tire width direction outer side and extending inward in the tire radial direction, and each side. The wall portion 3 has a pair of bead portions 4 located at the inner diameter end. A carcass ply 11 is arranged inside the tread portion 2 and the sidewall portion 3 so as to be bridged between the pair of bead portions 4.

A belt layer 12 and a belt reinforcing layer 13 are sequentially arranged outside the carcass ply 11 of the tread portion 2 in the tire radial direction, and a tread rubber 14 is further arranged outside the belt layer 12. An inner ply 15 for retaining air pressure is arranged inside the carcass ply 11.

The bead portion 4 has an annular bead core 41 formed by coating a converging body such as a steel wire with rubber, and an annular bead filler 42 that is connected to the bead core 41 and extends outward in the tire radial direction and has a triangular cross section.

A sidewall rubber 30 is provided on the outside of the carcass ply 11 of the sidewall portion 3 in the tire width direction.

Next, an apparatus for manufacturing the sidewall rubber 30 will be described.

As shown in FIG. 2, the manufacturing line of the sidewall rubber 30 includes an extruder 5 for extruding and molding a rubber member, a winding device 6 for winding the sidewall rubber 30 extruded in a strip shape from the extruder 5, and an extrusion. It has a plurality of conveying devices 71, 72, 73, 74, 75, 76 for conveying the sidewall rubber 30 between the machine 5 and the winding device 6.

The extruder 5 molds the strip-shaped sidewall rubber 30 by extruding a rubber member from a die having a trapezoidal cross section, for example.

The winding device 6 is formed in a cylindrical shape, and winds one end of the sidewall rubber 30 extruded in a strip shape from the extruder 5 around the outer peripheral surface to wind the sidewall rubber 30 in a roll shape at a constant speed. It is configured.

The plurality of conveying devices 71, 72, 73, 74, 75, and 76 are a conveyor device 71 that conveys the sidewall rubber 30 immediately after being extruded from the extruder 5 at a constant speed, and a plurality of through holes in the sidewall rubber 30. A roller 72 with needles forming 31...31, a first movable guide roller 73, a second movable guide roller 74, and a third movable guide roller 75 which are rotatable and movable in the vertical direction, and are rotatable. In addition, the fixed guide roller 76 is fixed in the vertical direction.

As shown in FIG. 3, the needle roller 72 includes a cylindrical drum main body 72a, disk-shaped side walls 72b and 72b (see FIG. 5) disposed at both ends thereof, the drum main body 72a and the side wall. 72b, 72b and a non-rotating stationary shaft member 72c that penetrates in the axial direction. The drum body 72a and the side wall portions 72b and 72b are rotatably supported by the stationary shaft member 72c via, for example, a bearing (not shown).

The roller 72 with a needle is provided with a plurality of needle members 81 that can rotate together with the drum main body 72a and that are needles for punching holes in the sidewall rubber 30 that can project and retract from the outer peripheral surface thereof. Each needle member 81 is formed in a conical shape in which the diameter decreases linearly from the radially inner side (root side) of the needle roller 72 to the radially outer side (tip side) of the needle roller 72.

The needle member 81 is formed, for example, in a three-stage storage type. Specifically, a cylindrical base portion 82 that is fixed inside the drum main body 72a and stores each needle member 81 retracted from the outer peripheral surface of the drum main body 72a, and a diameter smaller than the base portion 82, and a base It has a substantially trapezoidal conical intermediate portion 83 that is housed in the portion 82 and that supports the needle member 81 in the protruding state. In addition, the base portion 82, the intermediate portion 83, and the needle member 81 are appropriately arranged with a sealing member in each of the engaging portions described later so as to be in an airtight state.

Here, the protruding operation of the needle member 81 from the needle roller 72 and the retracting operation into the needle roller 72 will be described with reference to FIGS. 3 and 4.

By increasing the pressure in the drum body 72a (for example, injecting air), the needle member 81 and the intermediate portion 83, which are accommodated in the needle roller 72, are moved radially outward as shown in FIG. The needle member 81 is pushed out, and the needle member 81 is projected from the needle roller 72 as shown in FIG. Specifically, in the present embodiment, the lower end portion 81a of the needle member 81 and the upper end portion 83a of the intermediate portion 83 are formed so as to engage with each other, so that the needle member 81 is interlocked with the radial outward movement. Then, the intermediate portion 83 moves radially outward of the needle roller 72. Further, in this embodiment, by engaging the lower end portion 83b of the intermediate portion 83 and the upper end portion 82a of the base portion 82, the amount of protrusion of the intermediate portion 83 outward in the radial direction is regulated. The radial dimension H from the tip of the needle member 81 to the intermediate portion 83 in the protruding state has a predetermined length such that the needle member 81 penetrates the sidewall rubber 30.

By reducing the pressure in the drum body 72a (for example, sucking air), the needle member 81 and the intermediate portion 83 that are in a state of protruding from the outer peripheral surface of the needle roller 72 become the outer peripheral surface of the needle roller 72. It is retracted from and is stored in the base portion 82 (in the needle roller 72). A biasing means (not shown) such as a spring is provided between the needle member 81 and the base portion 82 to bias the protruding needle member 81 into the base portion 82. May be. In the present embodiment, the lower end portion 81a of the needle member 81 and the lower end portion 83b of the intermediate portion 83 are configured to be received by the lower end portion 82b of the base portion 82, so that the drum of the needle member 81 and the intermediate portion 83 is formed. Falling into the main body 72a is prevented.

Further, as shown in FIG. 5, the needle member 81 has a zigzag arrangement in which the distance L1 between the needle members 81 and 81 adjacent in the circumferential direction and the distance L2 between the needle members 81 and 81 adjacent in the axial direction are constant. It is arranged to be. Accordingly, the plurality of through holes 31... 31 formed in the sidewall rubber 30 are formed in a staggered arrangement like the arrangement of the needle members 81.

Further, since the needle member 81 has a conical shape as described above, the shape of the through hole 31 formed in the sidewall rubber 30 is a conical shape like the needle member 81 (FIG. 6). ..

As shown in FIG. 2, the first to third movable guide rollers 73, 74, 75 and the fixed guide roller 76 are arranged in order from the needle roller 72 side toward the winding device 6. In the present embodiment, the first movable guide roller 73 is arranged below the needle roller 72, the second movable guide roller 74 is arranged above the needle roller 72, and the third movable guide roller 75. Is disposed at a height position between the needle roller 72 and the first movable guide roller 73, and the fixed guide roller 76 is disposed at a height position between the second movable guide roller 74 and the third movable guide roller 75. It is located in. The first to third movable guide rollers 73, 74, 75 and the fixed guide roller 76 are arranged so as to be offset from each other.

The sidewall rubber 30 is below the first movable guide roller 73, above the second movable guide roller 74, below the third movable guide roller 75, and below the fixed guide roller 76. And is wound around from above and conveyed by these guide rollers 73, 74, 75, 76.

By the way, the sidewall rubber 30 has different tensions required for drilling depending on its thickness and hardness. Specifically, as shown in FIGS. 6 and 7, the required tension tends to increase as the thickness and hardness increase. Therefore, when the side wall rubber 30 is punched, it is necessary to apply tension to the side wall rubber 30 according to the thickness, the hardness, or both. A tension changing device 9 is provided.

The tension changing device 9 includes first to third movable guide rollers 73, 74, 75 and a fixed guide roller 76. That is, the first to third movable guide rollers 73, 74, 75 and the fixed guide roller 76 have a function of conveying the sidewall rubber 30 and a tension change for changing the tension applied to the sidewall rubber 30. Have a function.

As shown in FIG. 2, the tension changing device 9 changes the vertical position of each of the first to third movable guide rollers 73, 74, 75 to change the tension applied to the sidewall rubber 30. You can In the present embodiment, the tension applied to the sidewall rubber 30 is increased by increasing the vertical distance of the first to third movable guide rollers 73 to 75. This makes it possible to apply tension to the sidewall rubber 30 according to the thickness and/or hardness of the sidewall rubber 30.

Next, a method for manufacturing the sidewall rubber 30 will be described.

As shown in FIG. 2, the sidewall rubber 30 is extruded into a band shape from the die of the extruder 5 by the extruder 5 (extrusion step). The sidewall rubber 30 extruded from the extruder 5 is conveyed to the winding device 6 by the conveyor device 71, the needle roller 72, the first to third movable guide rollers 73 to 75, and the fixed guide roller 76 ( Transportation process).

The sidewall rubber 30 extruded from the extruder 5 passes through the conveyor device 71, the needle roller 72, the first to fourth guide rollers 73 to 76, and is wound around the winding device 6.

After that, as shown in FIGS. 6 and 7, the sidewall rubber 30 is applied with the first to the first tension so that a predetermined tension is applied according to the thickness or hardness of the sidewall rubber 30, or both of them. The vertical positions of the three movable guide rollers 73, 74, and 75 are adjusted (tension changing step). The change in the tension applied to the sidewall rubber 30 may be adjusted by the operator or the actuator.

The sidewall rubber 30 extruded from the extruder 5 has a plurality of through holes 31... 31 formed by the needle roller 72 in a state where a predetermined tension is applied in the conveying process (a perforating process). Specifically, the sidewall rubber 30 is wound around the outer peripheral surface of the drum body 72a of the needle roller 72, and is also conveyed from the extruder 5 side to the winding device 6 side by the needle roller 72. At this time, by increasing the pressure inside the drum main body 72a of the needle roller 72, the needle member 81 and the intermediate portion 83 project from the outer peripheral surface of the drum main body 72a and are wound around the needle roller 72 of the sidewall rubber 30. 31 are formed in the open portions.

31 are formed in the sidewall rubber 30, the pressure in the drum main body 72a is reduced, and the needle member 81 and the intermediate portion 83 retract from the outer peripheral surface of the needle roller 72 (drum main body 72a). At the same time, it is stored in the needle roller 72. 31 is prevented from being unnecessarily enlarged due to the needle member 81 being conveyed while being penetrated through the sidewall rubber 30 after the through holes 31.

As described above, in the punching step, while the sidewall rubber 30 is being conveyed by the needle roller 72, the sidewall rubber 30 can be sequentially punched, and the punching work can be performed efficiently while maintaining the process speed. It becomes possible to do it.

Then, the sidewall rubber 30 in which the plurality of through holes 31... 31 are formed is wound up by the winding device 6, and the sidewall rubber 30 as an intermediate product is completed. The sidewall rubber 30 wound into a roll by the winding device 6 is then rewound and attached to the outside in the radial direction of the carcass ply 11 in the molding step.

Further, in the molding step, as shown in FIG. 6, the shape of the plurality of through holes 31... 31 of the sidewall rubber 30 to be unwound is such that the diameter D1 on the side of the pasted surface 30b to be pasted on the carcass ply is opposite. It is preferable that the attachment is performed so that the diameter D2 on the attachment surface (profile surface) 30a side becomes small. As a result, the air remaining between the carcass ply 11 and the sidewall rubber 30 is likely to be discharged from the tire inside to the outside.

According to the method for manufacturing the sidewall rubber 30 described above, when a through hole for venting air is formed in the sidewall rubber 30, by applying a predetermined tension to the sidewall rubber 30, for example, a carcass ply. It is possible to surely make a hole in the side wall rubber 30 without unnecessarily increasing the thickness of the side wall rubber 30 having a lower rigidity than 11 or the like. Thereby, the air between the sidewall rubber 30 and the carcass ply 11 can be discharged from the plurality of through holes of the sidewall rubber 30 formed to have the optimum thickness. As a result, the performance and quality of the pneumatic tire can be secured.

Since the plurality of through holes 31... 31 can be provided in the sidewall rubber 30 while the sidewall rubber 30 is being carried by the needle roller 72 provided in the carrying process, the carrying of the sidewall rubber 30 is stopped. Without performing (without reducing the process speed), it is possible to perform the drilling efficiently.

Since the apparatus for manufacturing the sidewall rubber 30 includes the tension changing device 9 that changes the tension applied to the sidewall rubber 30, the sidewall rubber 30 can be applied with an optimum tension. As a result, as described above, by applying tension to the sidewall rubber 30 according to the thickness and/or the hardness of the sidewall rubber 30, more reliable holes can be made in the sidewall rubber 30. It will be possible.

In the manufacturing apparatus of the sidewall rubber 30, the needle member 81 is provided to be retractable from the needle roller 72, and the needle member 81 is housed in the needle roller 72 after the through hole 31 is formed. As a result, the needle member 81 is conveyed while penetrating the sidewall rubber 30 as in the case where the needle member 81 is always protruding from the needle roller 72, so that the shape of the through hole 31 is unnecessary. Further, it is possible to suppress the enlargement (extension) of the sidewall rubber 30 in the conveying direction (longitudinal direction).

The through hole 31 formed in the sidewall rubber 30 is formed such that the diameter D1 on the adhered surface 30b side adhered to the carcass ply 11 is larger than the diameter D2 on the non-adhered surface (profile surface) 30a side. Has been done. According to this, at the time of vulcanization molding, it is possible to suppress deterioration of the rubber flow from the side of the adhered surface 30b of the sidewall rubber 30 to the carcass ply 11 to the side opposite to the adhered surface 30a.

Since the hole for venting air is performed in the process in which only the sidewall rubber 30 is manufactured, only the sidewall rubber 30 can be monitored. As a result, for example, it is possible to more surely reduce the quality defects of the rubber member of the sidewall portion, as compared with the case where the punching is performed in the step of combining with other members such as the molding step.

In addition, when quality defects occur, it is possible to respond by simply stopping only the minimum line, so if you make holes in a process that is combined with other members such as the molding process, stop the entire tire manufacturing line. However, in the present embodiment, this can be dealt with only by stopping the step of manufacturing the sidewall rubber 30.

The invention is not limited to the configurations described in the above embodiments, and various modifications can be made.

For example, in the present embodiment, the needle member 81 housed in the needle roller 72 is configured to be able to be retracted and retracted radially inward and outward by air, but the needle member 81 can be retracted mechanically, for example. It may be configured.

For example, in the present embodiment, the tension applied to the sidewall rubber 30 is changed first, but the state of the through holes 31... 31 opened in the sidewall rubber 30 during the conveyance of the sidewall rubber 30. The tension may be changed on the way. In this case, for example, the state of the sidewall rubber 30 after the through hole is formed is monitored, and the tension is changed according to a defect such as the through hole not being formed.

For example, in the present embodiment, the tension changing device is formed of a plurality of movable guide rollers that can move in the vertical direction, but it may be formed of one movable guide roller. A normal tensioner may be used for the tension changing device.

1 Tire 3 Sidewall Part 5 Extruder 11 Carcass Ply 30 Sidewall Rubber (Rubber Member)
30a Anti-sticking surface 30b Sticking surface 31...31 Plural through holes 72 Roller with needle

Claims (6)

An extrusion step of extruding a rubber member constituting a tire sidewall portion from an extruder,
A carrying step of carrying the rubber member,
A winding step of winding the rubber member into a roll,
A step of boring a plurality of through holes in the rubber member during the conveying step,
In the carrying step, the rubber member is continuously carried,
The hole making step makes holes by winding the rubber member around a needle roller provided with a needle on the peripheral surface provided on the conveying path of the conveying step,
The method of manufacturing a sidewall rubber, wherein in the hole making step, holes are made in a state where a predetermined tension is applied to the rubber member. The method for manufacturing a sidewall rubber according to claim 1, further comprising a tension changing step of changing a tension applied to the rubber member in the punching step. In the boring step, the needle of the needle roller can be projected radially outward from the outer peripheral surface of the needle roller and can be retracted radially inward from the outer peripheral surface of the needle roller. The method for producing a sidewall rubber according to claim 1 or 2, wherein: The said hole making process WHEREIN: The adhered surface side adhere|attached to the carcass ply which forms the skeleton of the tire of the said rubber member makes a hole with a larger diameter than the non-adhered surface side. 2. The method for producing a sidewall rubber according to item 1. The method for producing a sidewall rubber according to claim 1, wherein in the carrying step, the needle roller is provided as a carrying device. The sidewall rubber manufacturing method according to claim 1, further comprising a molding step of molding a green tire after the winding step.

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