JP2021066105A - Tread rubber forming method and tread rubber forming equipment - Google Patents

Abstract

To provide a technology that can form tread rubber in a short time that can discharge the electric charge accumulated in a tire while improving the fuel efficiency and uniformity of the tire.SOLUTION: The method for forming the tread rubber comprises: first step S1 in which an insulating first rubber strip is wound while moving the same in the first axial direction; second step S2 in which an electrically conductive second rubber strip is wound over the outer circumferential surface of the first rubber strip; third step S3 in which an insulating third rubber strip is wound while moving the same in the first axial direction from a position on the side in the second axial direction relative to the second rubber strip, so that a part of the second rubber strip is exposed to the radial outer side of the tread rubber; and fourth step S4 in which an insulating fourth rubber strip is wound while moving the same in the second axial direction from a position on the side in the first or second axial direction relative to the second rubber strip, so that a part of the second rubber strip is exposed to the radial outer side of the tread rubber.SELECTED DRAWING: Figure 2

Description

The present invention relates to a technique for forming an annular tread rubber by spirally winding tape-shaped unvulcanized rubber strips.

Conventionally, there is known a technique of forming a tread rubber without a joint by spirally winding rubber strips to improve the uniformity of a tire (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2015-229438

By the way, in recent years, tires using silica as a reinforcing agent for tread rubber have been proposed in order to improve the fuel efficiency of automobiles. Since this silica has high electrical insulation, it causes an increase in the electrical resistance of the tire, and static electricity may be accumulated in the vehicle to cause radio interference such as radio noise.

Therefore, a technique is being studied in which a conductive rubber that penetrates a thickness of the tread rubber is used to conduct the inside of the tread rubber in the radial direction and the outside in the radial direction to discharge the electric charge accumulated in the tire.

However, the tread rubber through which the conductive rubber penetrates has a complicated structure as compared with a normal tread rubber, and the productivity is deteriorated. In particular, in the method of forming the tread rubber by spirally winding the rubber strips extruded from the gear pump, it is difficult to sufficiently increase the extrusion capacity of the gear pump. It takes a lot of time.

The present invention has been devised in view of the above circumstances, and provides a technique capable of forming a tread rubber capable of discharging the electric charge accumulated in a tire in a short time while improving the fuel efficiency and uniformity of the tire. The main purpose is that.

The first invention of the present invention is a method of forming an annular tread rubber by spirally winding a tape-shaped unvulvered rubber strip, wherein the insulating first rubber strip is at least the tread rubber. The first step of winding while moving in the first axial direction of the above, and the position of the conductive second rubber strip on the side opposite to the first axial direction of the first rubber strip in the second axial direction. A second step of winding the rubber strip over the outer peripheral surface of the first rubber strip, and a part of the second rubber strip from a position on the side of the second rubber strip in the second axial direction with respect to the insulating third rubber strip. The third step of winding the tread rubber so as to be exposed to the outside in the radial direction, and the insulating fourth rubber strip on the side of the first axial direction or the second axial direction with respect to the second rubber strip. It includes a fourth step of winding so that a part of the second rubber strip is exposed to the outside in the radial direction of the tread rubber while moving from the position at least in the second axial direction.

In the tread rubber forming method according to the first invention, the first rubber strip, the second rubber strip and the fourth rubber strip, the rubber material having a volume resistivity after vulcanization becomes 1 × 10 ⁸ [Omega] cm or more The second rubber strip is preferably made of a rubber material having a volume specific resistance of 1 × 10 ^{7 Ωcm or less after vulcanization.}

In the tread rubber forming method according to the first invention, it is desirable that the second step is started before the first step is completed.

In the tread rubber forming method according to the first invention, it is desirable that the third step is started before the second step is completed.

In the tread rubber forming method according to the first invention, the fourth rubber strip is wound on the side in the first axial direction with respect to the first rubber strip, and the fourth rubber strip is wound before the first step is completed. It is desirable that the fourth step begins.

In the tread rubber forming method according to the first invention, it is desirable that in the third step, the third rubber strip is wound while being moved at least in the first axial direction.

In the tread rubber forming method according to the first invention, the fourth rubber strip is wound between the second rubber strip and the third rubber strip, and the first step is performed before the third step is completed. It is desirable that four steps begin.

In the tread rubber forming method according to the first invention, it is desirable that in the third step, the third rubber strip is wound while being moved at least in the second axial direction.

In the tread rubber forming method according to the first invention, it is desirable that the first step includes a step of winding the first rubber strip while moving it in the second axial direction.

In the tread rubber forming method according to the first invention, it is desirable that the third step includes a step of winding the third rubber strip while moving it in the second axial direction.

In the tread rubber forming method according to the first invention, it is desirable that the third step includes a step of winding the third rubber strip while moving it in the first axial direction.

In the tread rubber forming method according to the first invention, it is desirable that the fourth step includes a step of winding the fourth rubber strip while moving it in the first axial direction.

The second invention of the present invention is an apparatus for forming an annular tread rubber by spirally winding tape-shaped unvulcanized rubber strips, and moves at least in the first axial direction of the tread rubber. The first applicator that supplies the insulating first rubber strip to the first winding position and the first applicator are located on the side opposite to the first axial direction in the second axial direction and are conductive. A second applicator that supplies the second rubber strip of the sex to the second winding position, and a third rubber strip that is located on the side of the second applicator in the second axial direction and has an insulating property are the second. A third applicator to be supplied to the third winding position so that a part of the rubber strip is exposed to the outside in the radial direction of the tread rubber, and the first axial direction or the second shaft with respect to the second applicator. Includes a fourth applicator that is located on the directional side and supplies an insulating fourth rubber strip to the fourth winding position while moving at least in the second axial direction.

In the tread rubber forming method of the first invention, the insulating rubber strips are spirally wound in the first step, the third step, and the fourth step, and the insulating rubber strip is spirally wound in the second step. The second rubber strip is wrapped around it. A part of the second rubber strip is exposed to the inside of the tread rubber in the radial direction, and the other part is exposed to the outside of the tread rubber in the radial direction. As a result, the tread rubber capable of discharging the electric charge accumulated in the tire is formed while improving the fuel efficiency performance of the tire.

In this tread rubber forming method, the tread rubber is dispersed and formed in the first step to the fourth step. Then, the first step to the fourth step can proceed at the same time in a part. Therefore, the tread rubber can be formed in a short time.

In the tread rubber forming apparatus of the second invention, the insulating rubber strip is spirally wound by using the first applicator, the third applicator, and the fourth applicator, and the second applicator is used. The conductive second rubber strip is wrapped around using. A part of the second rubber strip is exposed to the inside of the tread rubber in the radial direction, and the other part is exposed to the outside of the tread rubber in the radial direction. As a result, the tread rubber capable of discharging the electric charge accumulated in the tire is formed while improving the fuel efficiency performance of the tire.

In this tread rubber forming method, the tread rubber is dispersed and formed by using the first applicator to the fourth applicator. Then, the first applicator to the fourth applicator can operate at the same time in some parts. Therefore, the tread rubber can be formed in a short time.

It is sectional drawing of the tread rubber formed by the tread rubber forming method and the tread rubber forming apparatus of this invention. It is a flowchart which shows the procedure of the tread rubber forming method of one Embodiment of this invention. It is a side view which shows the structure of the tread rubber forming apparatus of one Embodiment of this invention. It is a schematic diagram which shows the said tread rubber forming apparatus in the 1st step. It is a schematic diagram which shows the said tread rubber forming apparatus in the 2nd step. It is a schematic diagram which shows the said tread rubber forming apparatus in a 3rd step. It is a schematic diagram which shows the said tread rubber forming apparatus in a 4th step. It is a schematic diagram which shows the modification of the said tread rubber forming apparatus in a 3rd step. It is a schematic diagram which shows the modification of the said tread rubber forming apparatus in a 4th step. It is sectional drawing which shows an example of the tread rubber formed by using the modification of the tread rubber forming apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a tire tread rubber formed by the tread rubber forming method and the tread rubber forming apparatus of the present embodiment. The tread rubber 1 is formed in an annular shape and includes an insulating portion 2 having electrical insulation and a conductive portion 3 having electrical conductivity. The conductive portion 3 is formed so as to penetrate the insulating portion 2 in the thickness direction (radial direction) of the tread rubber 1.

The insulating portion 2 is made of, for example, a rubber containing a large amount of silica as a reinforcing agent. In this tread rubber, the insulating portion 2, pressurized volume resistivity of after curing is 1 × 10 ⁸ what is constituted by a rubber material becomes more Ωcm is desirable. The conductive portion 3 is made of, for example, rubber in which a large amount of carbon is blended as a reinforcing agent. In this tread rubber, it is desirable that the conductive portion 3 is made of a rubber material having a volume specific resistance of 1 × 10 ^{7 Ωcm or less after vulcanization.} The volume specific resistance can be measured, for example, by using a rubber sample of 15 cm square and 2 mm in thickness, using an electric resistance measuring instrument under the conditions of an applied voltage of 500 V, an air temperature of 25 ° C., and a humidity of 50%.

The conductive portion 3 penetrating the insulating portion 2 conducts the inside of the tread rubber 1 in the radial direction and the outside in the radial direction. Since conductive rubber such as topping rubber or sidewall rubber of the belt member is arranged inside the tread rubber 1 in the radial direction, the electric charge accumulated in the tire is discharged via the conductive portion 3. ..

FIG. 2 is a flowchart showing the procedure of the tread rubber forming method of the present embodiment. Further, FIG. 3 shows an example of a tread rubber forming apparatus preferably used in the tread rubber forming method.

As shown in FIG. 2, the present tread rubber forming method includes a first step S1 for winding the insulating first rubber strip 11 and a second step S2 for winding the conductive second rubber strip 12, and the insulating property. The third step S3 for winding the third rubber strip 13 and the fourth step S4 for winding the insulating fourth rubber strip 14 are included (for the first rubber strip 11 to the fourth rubber strip 14, the first rubber strip 11 to the fourth rubber strip 14 are included. (See FIGS. 4 to 10). The first rubber strip 11, the third rubber strip 13, and the fourth rubber strip 14 form the insulating portion 2, and the second rubber strip 12 forms the conductive portion 3.

As shown in FIG. 3, the tread rubber forming apparatus 100 supplies the first rubber strip 11 to the first winding position and the second rubber strip 12 to the second winding position. It includes an applicator 102, a third applicator 103 that supplies the third rubber strip 13 to the third winding position, and a fourth applicator 104 that supplies the fourth rubber strip 14 to the fourth winding position.

The first rubber strip 11 to the fourth rubber strip 14 are wound around the outer side of the rotationally driven molding drum 105 in the radial direction to form the annular tread rubber 1. The first applicator 101, the third applicator 103, and the fourth applicator 104 are configured to be movable in the axial direction of the molding drum 105 (the direction perpendicular to the paper surface in FIG. 3). That is, the first applicator 101, the third applicator 103, and the fourth applicator 104 are configured to be movable in the first axial direction of the tread rubber 1 or in the second axial direction opposite to the first axial direction. .. The forming drum 105 may be configured to be movable in the axial direction thereof. Further, the first applicator 101, the second applicator 102, the third applicator 103, and the fourth applicator 104 are configured to be movable in the front-rear direction perpendicular to the axial direction of the molding drum 105, if necessary. You may.

A known rubber strip supply device can be applied to the first applicator 101 to the fourth applicator 104. For example, the first applicator 101 is composed of a device having a belt for transporting the first rubber strip 11 and a roller for pressing the winding portion of the first rubber strip 11 inward in the radial direction of the molding drum 105. sell. The configurations of the second applicator 102 to the fourth applicator 104 are the same as those of the first applicator 101.

For example, a gear pump (not shown) is provided on the upstream side of the first applicator 101, the third applicator 103, and the fourth applicator 104. The gear pump allows the first rubber strip 11, the third rubber strip 13, and the fourth rubber strip 14 to be continuously and stably supplied and easily wound even if the rubber material is difficult to mix, process, and attach. Is. On the upstream side of the second applicator 102, for example, a drum or bobbin around which the second rubber strip 12 is wound (not shown) is provided.

The rotation of the forming drum 105 and the movement of the first applicator 101, the third applicator 103, the fourth applicator 104, and the forming drum 105 are controlled by a control unit (not shown). The control unit synchronously controls the first applicator 101 and the like or the molding drum 105. Hereinafter, the form in which the first applicator 101, the third applicator 103, and the fourth applicator 104 can be moved will be described, but the same applies to the form in which the molding drum 105 is movable.

FIG. 4 shows the tread rubber forming device 100 in the first step S1. In the first step S1, the first applicator 101 supplies the first rubber strip 11 to the first winding position P1 while moving in the first axial direction D1 of the tread rubber 1. As a result, the first rubber strip 11 is wound while moving in the first axial direction D1. For convenience of explanation, the first axial direction D1 is the right direction in FIG. 4, but it may be the left direction. The contour of the cross section of the wound first rubber strip 11 depends on the contour of the cross section of the tread rubber 1, but in the present embodiment, it exhibits a shape having a flat portion at the center and slope portions at both ends.

FIG. 5 shows the tread rubber forming device 100 in the second step S2. In the second step S2, the second applicator 102 supplies the second rubber strip 12 to the second winding position P2. As a result, the second rubber strip 12 is wound around. The second winding position P2 is located on the side of the first winding position P1 in the second axial direction D2 opposite to the first axial direction D1.

In the present embodiment, the width of the second rubber strip 12 is configured to correspond to the width of the conductive portion 3. The width of the second rubber strip 12 may be smaller than the width of the conductive portion 3. In this case, for example, the conductive portion 3 is formed by spirally winding the second rubber strip 12 while the second applicator 102 moves in the first axial direction D1 of the tread rubber 1.

In the second step S2, the edge of the second rubber strip 12 in the second axial direction D2 is located closer to the edge of the first rubber strip 11 in the second axial direction D2 than the edge of the first rubber strip 11 in the second axial direction D2. The second winding position P2 is set. As a result, the edge of the second rubber strip 12 in the second axial direction D2 is exposed inside the tread rubber 1 in the radial direction.

Further, the second winding position P2 is set so that the edge of the second rubber strip 12 in the first axial direction D1 is located outside the tread rubber in the radial direction with respect to the first rubber strip 11. In the present embodiment, the first axial direction D1 of the second rubber strip 12 extends beyond the slope of the first rubber strip 11 and extends over the flat portion.

FIG. 6 shows the tread rubber forming device 100 in the third step S3. In the third step S3, the third applicator 103 located on the side of the second axial direction D2 with respect to the second applicator 102 (see FIG. 5) moves in the first axial direction D1 and the third rubber strip. 13 is supplied to the third winding position P3. As a result, the third rubber strip 13 is wound while moving in the first axial direction D1. Further, as the third rubber strip 13 moves in the first axial direction D1, the third rubber strip 13 is wound around the outer side in the radial direction of the second rubber strip 12, and is in the second axial direction with respect to the second rubber strip 12. A third rubber strip 13 is formed on the side of D2.

In the third step S3, the third winding position P3 is positioned so that the third rubber strip 13 is located at least on the side of the second rubber strip 12 on the side of the first axial direction D1 and on the side of the second axial direction D2. It is set. As a result, the third rubber strip 13 is wound so that a part of the second rubber strip 12 is exposed to the outside in the radial direction of the tread rubber 1. In the third step S3, the third rubber strip 13 may be wound by using the first applicator 101 or the fourth applicator 104.

FIG. 7 shows the tread rubber forming device 100 in the fourth step S4. In the tread rubber forming apparatus 100, the fourth applicator 104 is located on the side in the first axial direction D1 with respect to the first applicator 101 and the second applicator 102 (see FIGS. 4 and 5).

In the fourth step S4, the fourth applicator 104 located on the side of the first axial direction D1 with respect to the first applicator 101 winds the fourth rubber strip 14 in the fourth while moving in the second axial direction D2. Supply to position P4. As a result, the fourth rubber strip 14 is wound while moving in the second axial direction D2, and the first rubber strip 11 and the fourth rubber strip 14 are formed on the side of the second rubber strip 12 in the first axial direction D1. Will be done.

In the fourth step S4, the edge of the fourth rubber strip 14 on the side of the second axial direction D2 is at least closer to the side of the first axial direction D1 than the edge of the second rubber strip 12 on the side of the first axial direction D1. The fourth winding position P4 is set so as to be positioned. As a result, the fourth rubber strip 14 is wound so that a part of the second rubber strip 12 is exposed to the outside in the radial direction of the tread rubber 1. In the fourth step S4, the fourth rubber strip 14 may be wound by using the first applicator 101 or the third applicator 103.

In this tread rubber forming method, the insulating first rubber strip 11, the third rubber strip 13, and the fourth rubber strip 14 are spirally wound in the first step S1, the third step S3, and the fourth step S4. , The conductive second rubber strip 12 is wound in the second step S2. A part of the second rubber strip 12 (the end on the side of the second axial direction D2) is exposed inward in the radial direction of the tread rubber 1, and the other part (the end on the side of the first axial direction D1) is exposed. It is exposed to the outside in the radial direction of the tread rubber 1. As a result, the tread rubber 1 capable of discharging the electric charge accumulated in the tire while improving the fuel efficiency performance of the tire is formed.

In this tread rubber forming method, the tread rubber 1 is dispersed and formed in the first step S1 to the fourth step S4. Then, as will be described later, the first step S1 to the fourth step S4 can proceed at the same time in a part. Therefore, the tread rubber 1 capable of discharging the electric charge accumulated in the tire can be formed in a short time. In particular, the tread rubber 1 can be formed in a short time even in a form in which a gear pump having a poor supply capacity of a rubber strip is applied.

In the tread rubber forming apparatus 100, the insulating first rubber strip 11, the third rubber strip 13, and the fourth rubber strip 14 are spiraled by using the first applicator 101, the third applicator 103, and the fourth applicator 104. The second rubber strip 12 is wound around the conductive second rubber strip 12 by using the second applicator 102. A part of the second rubber strip 12 is exposed inside the tread rubber 1 in the radial direction, and the other part is exposed outside the tread rubber 1 in the radial direction. As a result, the tread rubber 1 capable of discharging the electric charge accumulated in the tire while improving the fuel efficiency performance of the tire is formed.

In the tread rubber forming apparatus 100, the tread rubber 1 is dispersedly formed by using the first applicator 101 to the fourth applicator 104. Then, the first applicator 101 to the fourth applicator 104 can operate at the same time in some parts. Therefore, the tread rubber 1 capable of discharging the electric charge accumulated in the tire can be formed in a short time.

As described below, in the present tread rubber forming method, the first step S1, the second step S2, the third step S3, and the fourth step S4 do not necessarily have to be executed in the order shown in FIG.

In this tread rubber forming method, it is desirable that the second step S2 is started before the first step S1 is completed. For example, in the first step S1, the edge of the first rubber strip 11 on the side of the second axial direction D2 passes through the edge of the second winding position P2 on the side of the first axial direction D1, and then the second rubber strip 12 Winding may be started. In such a configuration, the first step S1 and the second step S2 partially proceed at the same time, and the production efficiency of the tread rubber 1 is improved.

In this tread rubber forming method, it is desirable that the third step S3 is started before the second step S2 is finished. For example, the third step S3 may be started before the second step S2 is started. In this case, in the third step S3, the second step is performed before the edge of the third rubber strip 13 on the first axial direction D1 side reaches the edge of the second winding position P2 on the first axial direction D1 side. It suffices if S2 is completed. In such a configuration, the second step S2 and the third step S3 partially proceed at the same time, and the production efficiency of the tread rubber 1 is improved.

In this tread rubber forming method, it is desirable that the fourth step S4 is started before the first step S1 is finished. For example, in the fourth step S4, before the edge of the fourth rubber strip 14 on the side of the second axial direction D2 reaches the edge of the first winding position P1 on the side of the first axial direction D1, the first step S1 Should be completed. In such a configuration, the first step S1 and the fourth step S4 partially proceed at the same time, and the production efficiency of the tread rubber 1 is improved.

8 and 9 show a tread rubber forming device 100A which is a modification of the tread rubber forming device 100. In the tread rubber forming apparatus 100A, the fourth applicator 104 is located on the side of the second axial direction D2 with respect to the first applicator 101 and the second applicator 102 (see FIGS. 4 and 5). , It is different from the tread rubber forming device 100.

The configuration of the tread rubber forming device 100 described above can be adopted for a portion of the tread rubber forming device 100A not described below. That is, in the tread rubber forming apparatus 100A, the first step S1 and the second step S2 are executed in the same manner as in FIGS. 4 and 5.

FIG. 8 shows the tread rubber forming device 100A in the third step S3. In the third step S3, the third applicator 103 located on the side of the second axial direction D2 with respect to the second applicator 102 winds the third rubber strip 13 in the third while moving in the second axial direction D2. Supply to position P3. As a result, the third rubber strip 13 is wound while moving in the second axial direction D2.

In the third step S3 of the tread rubber forming method using the tread rubber forming apparatus 100A, the third rubber strip 13 is at least in the second axial direction D2 from the edge of the second rubber strip 12 on the side of the second axial direction D2. The third winding position P3 is set so as to be located on the side. As a result, the third rubber strip 13 is wound on the side of the second rubber strip 12 in the second axial direction D2 at a distance, and the entire second rubber strip 12 is exposed to the outside in the radial direction of the tread rubber 1.

In the third step S3 of the tread rubber forming method using the tread rubber forming apparatus 100A, the third applicator 103 supplies the third rubber strip 13 to the third winding position P3 while moving in the first axial direction D1. It may be configured to do so. As a result, the third rubber strip 13 is wound while moving in the first axial direction D1.

FIG. 9 shows the tread rubber forming device 100A in the fourth step S4. In the tread rubber forming apparatus 100A, the fourth applicator 104 is on the side of the second applicator 102 and the first applicator 101 in the second axial direction D2, and is the first with respect to the third applicator 103. It is located on the side of the axial direction D1. As a result, the fourth rubber strip 14 is wound between the second rubber strip 12 and the third rubber strip 13.

In the fourth step S4, the fourth applicator 104 located on the side of the second axial direction D2 with respect to the second applicator 102 winds the fourth rubber strip 14 in the fourth while moving in the second axial direction D2. Supply to position P4. As a result, the fourth rubber strip 14 is wound while moving in the second axial direction D2, and the third rubber strip 13 and the fourth rubber strip 14 are formed on the side of the second rubber strip 12 in the second axial direction D2. Will be done.

In the fourth step S4, the fourth winding position P4 is located so that the fourth rubber strip 14 is located at least on the side of the second rubber strip 12 on the side of the second axial direction D2 with respect to the edge of the second rubber strip 12 on the side of the second axial direction D2. It is set. As a result, the fourth rubber strip 14 is wound so that a part of the second rubber strip 12 is exposed to the outside in the radial direction of the tread rubber 1. Also in the tread rubber forming apparatus 100A, a part of the second rubber strip 12 (the end on the side of the second axial direction D2) is exposed inside the tread rubber 1 in the radial direction, and the other part (the first axial direction). The end on the side of D1) is exposed to the outside in the radial direction of the tread rubber 1.

Also in the tread rubber forming method using the tread rubber forming apparatus 100A, the tread rubber 1 is dispersed and formed in the first step S1 to the fourth step S4. Then, the first step S1 to the fourth step S4 can proceed at the same time in a part. Therefore, the tread rubber 1 capable of discharging the electric charge accumulated in the tire can be formed in a short time.

Even in the tread rubber forming method using the tread rubber forming apparatus 100A, the first step S1, the second step S2, the third step S3 and the fourth step S4 are not necessarily executed in the order shown in FIG. You may. Then, it is desirable that the second step S2 is started before the first step S1 is completed. Further, it is desirable that the third step S3 is started before the second step S2 is completed.

In this tread rubber forming method, it is desirable that the fourth step S4 is started before the third step S3 is completed. For example, in the fourth step S4, before the edge of the fourth rubber strip 14 on the side of the second axial direction D2 reaches the edge of the third winding position P3 on the side of the first axial direction D1, the third step S3 Should be completed. In such a configuration, the third step S3 and the fourth step S4 partially proceed at the same time, and the production efficiency of the tread rubber 1 is improved.

It is desirable that the first step S1 shown in FIG. 4 includes a step of winding the first rubber strip 11 while moving it in the second axial direction D2. For example, the first rubber strip 11 is wound while being moved in the first axial direction D1 at the first winding position P1, and then folded back at the end of the first winding position P1 on the side of the first axial direction D1. While moving in the biaxial direction D2, they are wound so as to end before the second winding position P2. As a result, the volume of the insulating rubber at the first winding position P1 can be easily secured.

It is desirable that the third step S3 shown in FIG. 6 includes a step of winding the third rubber strip 13 while moving it in the second axial direction D2. For example, the third rubber strip 13 is wound while being moved in the second axial direction D2 at the third winding position P3, and then folded back at the end of the third winding position P3 on the second axial direction D2 side. It is wound while being moved in the uniaxial direction D1. As a result, the volume of the insulating rubber at the third winding position P3 can be easily secured.

It is desirable that the third step S3 shown in FIG. 8 includes a step of winding the third rubber strip 13 while moving it in the first axial direction D1. For example, the third rubber strip 13 is wound while being moved in the first axial direction D1 at the third winding position P3, and then folded back at the end of the third winding position P3 on the side of the first axial direction D1. It is wound while being moved in the biaxial direction D2. As a result, the volume of the insulating rubber at the third winding position P3 can be easily secured.

It is desirable that the fourth step S4 shown in FIG. 7 or 9 includes a step of winding the fourth rubber strip 14 while moving it in the first axial direction D1. For example, the fourth rubber strip 14 is wound while being moved in the first axial direction D1 at the fourth winding position P4, and then folded back at the end of the fourth winding position P4 on the first axial direction D1 side. It is wound while being moved in the biaxial direction D2. As a result, the volume of the insulating rubber at the fourth winding position P4 can be easily secured.

FIG. 10 shows the first step S1 including the step of winding the first rubber strip 11 while moving it in the second axial direction D2 using the tread rubber forming device 100A, and the third rubber strip 13 in the second axial direction D2. The tread rubber 1 formed through the third step S3 including the step of winding while moving the tread rubber 1 is shown. In the tread rubber 1 shown in FIG. 10, the volume of the insulating rubber can be easily secured in the region corresponding to the shoulder portion.

Although the tread rubber forming method and the tread rubber forming apparatus 100 of the present invention have been described in detail above, the present invention is not limited to the above-mentioned specific embodiment, but is modified to various embodiments. For example, the tread rubber 1 is not limited to the form formed on the radial outer side of the forming drum 105, but can also be applied to the form formed on the radial outer side of a belt member or the like constituting a tire.

1 Tread rubber 11 1st rubber strip 12 2nd rubber strip 13 3rd rubber strip 14 4th rubber strip 100 Tread rubber forming device 101 1st applicator 102 2nd applicator 103 3rd applicator 104 4th applicator D1 1st 1 axial direction D2 2nd axial direction S1 1st process S2 2nd process S3 3rd process S4 4th process

Claims (13)

A method of forming an annular tread rubber by spirally winding a tape-shaped unvulcanized rubber strip.
The first step of winding the insulating first rubber strip while moving it at least in the first axial direction of the tread rubber, and
A second step of winding the conductive second rubber strip from a position on the side opposite to the first axial direction of the first rubber strip in the second axial direction over the outer peripheral surface of the first rubber strip.
A second rubber strip having an insulating property is wound so that a part of the second rubber strip is exposed to the outside in the radial direction of the tread rubber from a position on the side in the second axial direction with respect to the second rubber strip. 3 steps and
One of the second rubber strips while moving the insulating fourth rubber strip from the position on the side of the first axial direction or the second axial direction with respect to the second rubber strip in at least the second axial direction. A fourth step of winding the tread rubber so that the portion is exposed to the outside in the radial direction is included.
Tread rubber forming method. The first rubber strip, the second rubber strip and the fourth rubber strip is made of a rubber material having a volume resistivity after vulcanization becomes 1 × 10 ⁸ [Omega] cm or higher,
The tread rubber forming method according to claim 1, wherein the second rubber strip is made of a ^{rubber material having a volume specific resistance of 1 × 10 7 Ωcm or less after vulcanization.} The tread rubber forming method according to claim 1 or 2, wherein the second step is started before the first step is completed. The tread rubber forming method according to any one of claims 1 to 3, wherein the third step is started before the second step is completed. The fourth rubber strip is wound on the side in the first axial direction with respect to the first rubber strip, and the fourth step is started before the first step is completed. The tread rubber forming method according to any one. The tread rubber forming method according to claim 5, wherein in the third step, the third rubber strip is wound while being moved at least in the first axial direction. Any of claims 1 to 4, wherein the fourth rubber strip is wound between the second rubber strip and the third rubber strip, and the fourth step is started before the third step is completed. The tread rubber forming method described in Crab. The tread rubber forming method according to claim 7, wherein in the third step, the third rubber strip is wound while being moved at least in the second axial direction. The tread rubber forming method according to any one of claims 1 to 8, wherein the first step includes a step of winding the first rubber strip while moving it in the second axial direction. The tread rubber forming method according to claim 6, wherein the third step includes a step of winding the third rubber strip while moving it in the second axial direction. The tread rubber forming method according to claim 8, wherein the third step includes a step of winding the third rubber strip while moving it in the first axial direction. The tread rubber forming method according to any one of claims 1 to 11, wherein the fourth step includes a step of winding the fourth rubber strip while moving it in the first axial direction. A device that forms an annular tread rubber by spirally winding tape-shaped unvulcanized rubber strips.
A first applicator that supplies an insulating first rubber strip to the first winding position while moving at least in the first axial direction of the tread rubber.
A second applicator located on the side in the second axial direction opposite to the first axial direction with respect to the first applicator and supplying the conductive second rubber strip to the second winding position.
A part of the second rubber strip of the tread rubber, which is located on the side of the second applicator in the second axial direction and has an insulating third rubber strip while moving at least in the first axial direction. A third applicator that supplies the third winding position so that it is exposed to the outside in the radial direction,
The insulating fourth rubber strip is supplied to the fourth winding position while moving in the first axial direction or the second axial direction with respect to the second applicator and moving at least in the second axial direction. Including the 4th applicator to
Tread rubber forming device.

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