JP2021116040A - Tire and rubber element formation method - Google Patents

Abstract

To provide a technique for improving dynamic balance in a tire having a jointless structure.SOLUTION: The tire has a first area 111, where weight distribution of a strip member 110 per unit length in a tire axial direction becomes uneven, at one end part 101 in the tire axial direction of a rubber element 100, and has a second area 112, where weight distribution of the strip member 110 per unit length in the tire axial direction becomes uneven, at the other end part 102 in the tire axial direction of the rubber element 100. When the rubber element 100 is expanded into a flat face, an area center G2 of the second area 112 falls within a range of 0±15° around a tire axis with respect to an area center G1 of the first area 111.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tire having a jointless structure formed by spirally winding a strip-shaped member.

Conventionally, tires having improved uniformity performance by spirally winding a strip-shaped member have been known. For example, Patent Document 1 discloses a tire in which the static balance is improved by setting the deviation between the winding start position and the winding end position in the tire circumferential direction to be 0 to 5 mm.

Japanese Unexamined Patent Publication No. 2002-178415

In the tire shown in Patent Document 1, winding start positions and winding end positions are arranged at both ends in the axial direction of the rubber member, and the strip-shaped member is wound so as to be inclined with respect to the tire circumferential direction. Therefore, at both ends of the rubber member in the axial direction, there is a region in which the weight distribution of the strip-shaped member per unit length is non-uniform in the tire axial direction.

However, as described above, when the deviation between the winding start position and the winding end position in the tire circumferential direction is 0 to 5 mm, the position of the center of gravity of one end in the axial direction of the rubber member and the position of the center of gravity of the other end in the axial direction of the rubber member The dynamic balance deteriorates because the tires shift in the tire circumferential direction.

The present invention has been devised in view of the above circumstances, and a main object of the present invention is to provide a technique for enhancing dynamic balance in a tire having a jointless structure.

The first invention of the present invention is a tire including a rubber member formed by spirally winding a band-shaped member from one side to the other side of the tire equatorial line, and is provided at one end of the rubber member in the tire axial direction. The rubber member has a first region in which the weight distribution of the strip-shaped member is non-uniform in the tire axial direction, and the other end of the rubber member in the tire axial direction is per unit length in the tire axial direction. When the rubber member has a second region in which the weight distribution of the strip-shaped member is non-uniform and the rubber member is developed in a plane, the area center of the second region is the area center of the tire shaft with respect to the area center of the first region. Around, it exists in the range of 0 ± 15 °.

In the tire according to the present invention, the winding start position of the strip-shaped member is arranged at the one end portion of the rubber member, and the winding end position of the strip-shaped member is arranged at the other end portion of the rubber member. Is desirable.

In the tire according to the present invention, it is desirable that the winding end position is displaced by 240 ± 15 ° around the tire shaft with respect to the winding start position.

In the tire according to the present invention, in the intermediate region sandwiched between the first region and the second region in the tire axial direction, the weight distribution of the strip-shaped member per unit length in the tire axial direction is uniform. Is desirable.

In the tire according to the present invention, it is desirable that the band-shaped member is wound so that the rubber member has a symmetrical shape with respect to the equator of the tire.

In the tire according to the present invention, it is desirable that the strip-shaped member is wound at a pitch equal to the tire axial direction.

In the tire according to the present invention, it is desirable that the strip-shaped member is wound around the one end portion of the rubber member and the other end portion of the rubber member so as to be inclined with respect to the tire circumferential direction.

In the tire according to the present invention, it is desirable that the strip-shaped member is wound in the tire circumferential direction at the one-sided end edge portion of the rubber member and the other-side end edge portion of the rubber member. ..

In the tire according to the present invention, when the rubber member is developed in a plane, it is desirable that the first region and the second region have a triangular shape.

It is desirable that the tire according to the present invention includes a plurality of the rubber members.

In the tire according to the present invention, it is desirable that the center of the area of the first region of the strip-shaped member constituting each rubber member is deviated in the tire circumferential direction.

In the tire according to the present invention, it is desirable that the center of the area of the second region of the strip-shaped member constituting each rubber member is deviated in the tire circumferential direction.

In the tire according to the present invention, it is desirable that the rubber member includes an inner liner rubber.

In the tire according to the present invention, it is desirable that the rubber member includes a tread rubber.

In the tire according to the present invention, it is desirable that the rubber member includes a band ply whose band cord is covered with a topping rubber.

The second invention of the present invention is a method of forming a rubber member for a tire by spirally winding a band-shaped member around the outer peripheral surface of the drum, from the winding start position of one end of the band-shaped member in the drum axial direction. The winding start position includes a step of winding the strip-shaped member at the winding end position of the other end in the drum axis direction, and the winding end position is 240 ± 15 around the drum shaft with respect to the winding start position.゜ It is out of alignment.

In the tire of the first invention, when the rubber member is deployed on the plane, the area center of the first region and the area center of the second region are substantially at the same position in the tire circumferential direction. Be arranged. As a result, the dynamic balance of the tire is easily improved, and the uniformity performance is improved.

In the rubber member forming method of the second invention, the band-shaped member ends winding at a position shifted by 240 ± 15 ° around the drum shaft with respect to the winding start position. Therefore, the area center of the first region where the weight distribution at one end of the rubber member is non-uniform and the area center of the second region where the weight distribution at the other end of the rubber member is non-uniform. However, they are arranged at substantially the same position in the tire circumferential direction. As a result, the dynamic balance of the tire is easily improved, and the uniformity performance is improved.

It is sectional drawing which shows one Embodiment of the tire of this invention. The figure which shows the outline of the forming apparatus and the forming method of the rubber member used for the tire of FIG. The figure which shows typically the rubber member developed on the plane. The figure which shows the weight distribution of the band-shaped member which comprises the rubber member of FIG. The figure which shows typically the deformation example of the rubber member of FIG. The figure which shows the weight distribution of the band-shaped member which comprises the rubber member of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a meridional cross section including a tire shaft of the tire 1 of the present embodiment.

The tire 1 of the present embodiment is arranged on the outside of the carcass 6 of the sidewall portion 3 in the tire axial direction, and the toroid-shaped carcass 6 straddling the pair of bead portions 4 via the tread portion 2 and the pair of sidewall portions 3. Includes sidewall rubber 3G.

In the tire 1 of the present embodiment, the carcass 6 is bridged between the bead portions 4 and 4, and the belt layer 7 is arranged inside the tread portion 2 and outside the carcass 6. The bead portions 4 and 4 are attached to the regular rim R.

A "regular rim" is a rim defined for each tire in the standard system including the standard on which the tire 1 is based. For example, "standard rim" for JATTA and "Design Rim" for TRA. If it is ETRTO, it is "Measuring Rim".

The normal state is a state in which the tire 1 is rim-assembled on the regular rim R and the normal internal pressure is applied and no load is applied. "Regular internal pressure" is the air pressure defined for each tire in the standard system including the standard on which the tire is based. For JATMA, "maximum air pressure", for TRA, the table "TIRE LOAD LIMITS" The maximum value described in "AT VARIOUS COLD INFLATION PRESSURES", or "INFLATION PRESSURE" for ETRTO. If the tires are for passenger cars, the regular internal pressure is, for example, 180 kPa. Hereinafter, unless otherwise specified, the dimensions and the like of each part of the tire are values measured in this normal state.

The carcass 6 is composed of one or more carcass cords arranged at an angle of, for example, 75 ° to 90 ° with respect to the tire circumferential direction, or one carcass ply 6A in this example. For the carcass cord, for example, an organic fiber cord such as aromatic polyamide or rayon is preferably adopted. The carcass ply 6A has folded portions 6b that are folded back and locked from the inside to the outside around the bead core 5 of the bead portion 4 at both ends of the main body portion 6a straddling the bead portions 4 and 4. A bead apex rubber 8 for reinforcing the bead portion extending from the bead core 5 to the outside in the radial direction of the tire is arranged between the main body portion 6a and the folded portion 6b.

The belt layer 7 is composed of two or more belt cords arranged at an angle of, for example, 15 to 45 ° with respect to the tire circumferential direction, in this example, two belt plies 7A and 7B. For the belt cord, for example, steel, aramid, rayon, or the like is preferably adopted. The belt plies 7A and 7B are configured by covering the plurality of belt cords with the topping rubber. The belt plies 7A and 7B are laminated, and the cords intersect each other between the plies, so that the tread portion 2 is reinforced with high rigidity.

A band layer 9 made of a band ply 9A in which a band cord is spirally wound in the circumferential direction is provided on the outer side of the belt layer 7 in the radial direction of the tire for the purpose of improving high-speed durability and steering stability. In this example, an organic fiber such as nylon is preferably used for the band cord. The band layer 9 may be omitted.

Tread rubber 2G is arranged on the outer side of the band layer 9 in the radial direction of the tire. The tread rubber 2G may have a two-layer structure of a base layer on the inner side in the radial direction of the tire and a cap layer on the outer side in the radial direction of the tire. Further, in the sidewall portion 3, sidewall rubber 3G is arranged on the outer side in the tire radial direction and the outer side in the tire axial direction of the carcass 6.

An inner liner rubber 10 is arranged inside the carcass 6. The inner liner rubber 10 is made of, for example, an air-impermeable butyl rubber containing 50 parts by weight or more of butyl halide in the rubber, and is useful for maintaining the tire internal pressure.

The tread rubber 2G, the band ply 9A, and the inner liner rubber 10 are rubber members formed by spirally winding an unvulcanized strip-shaped member. The strip-shaped members are arranged from one side to the other side of the tire equator. As a result, the rubber member is arranged from one side to the other side of the tire equator.

FIG. 2 shows an outline of a forming apparatus and a forming method of the rubber member 100. The forming device 200 includes a drum 201 around which the strip-shaped member 110 is wound, and an applicator 210 for supplying the strip-shaped member 110.

The drum 201 is configured to be rotatable around the drum axis. The applicator 210 is configured to be movable in the axial direction of the drum 201. The drum 201 may be configured to be movable in the axial direction thereof. Further, the applicator 210 may be configured to be movable in the front-rear direction perpendicular to the axial direction of the drum 201, if necessary.

A known rubber strip feeder may be applied to the applicator 210. For example, the applicator 210 may be composed of a device having a belt for transporting the strip-shaped member 110 and a roller for pressing the winding portion of the strip-shaped member 110 inward in the radial direction of the drum 201.

The rubber member 100 is formed by winding the strip-shaped member 110 around the outer peripheral surface 202 of the drum 201 while rotating the drum 201 and moving the applicator 210 in the axial direction of the drum 201. The rubber member 100 is formed from one side to the other side of the drum equator. As a result, the rubber member 100 extending from one side to the other side of the tire equator CL is formed across the tire equator CL.

FIG. 3 schematically shows a rubber member 100 developed on a flat surface. In FIG. 3, the length in the drum axis direction (tire axis direction) is shown in the horizontal direction, and the rotation angle around the drum axis with the winding start position 110S of the strip-shaped member 110 as a reference (0 °) is shown in the vertical direction. .. With reference to FIGS. 2 and 3, the rubber member 100 is formed by winding the band-shaped member 110 at the winding start position 110S of the one end portion 101 and winding the band-shaped member 110 at the winding end position 110E of the other end portion 102. Including the ending step S2.

FIG. 4 shows the weight distribution of the strip-shaped member 110 per unit length in the tire axial direction. In FIG. 4, the horizontal axis represents the length in the tire axial direction, and the vertical axis represents the weight of the strip-shaped member 110 per unit length.

In the forming device 200, since the drum 201 is rotated to move the applicator 210 in the axial direction of the drum 201, the strip-shaped member 110 wound around the drum 201 is inclined with respect to the tire circumferential direction of the drum 201. Therefore, as shown by hatching in FIG. 3, the weight of the strip-shaped member 110 per unit length in the tire axial direction is non-uniform at both ends of the rubber member 100 in the tire axial direction (in other words, in other words). The weight of the strip-shaped member 110 per unit length is not constant in the tire axial direction.) The first region 111 and the second region 112 are generated.

That is, at one end 101 of the rubber member 100 in the tire axial direction, a first region 111 in which the weight distribution of the strip-shaped member 110 is non-uniform is generated. On the other hand, at the other end 102 of the rubber member 100 in the tire axial direction, a second region 112 in which the weight distribution of the strip-shaped member 110 is non-uniform is generated. The first region 111 and the second region 112 are regions in which the weight of the strip-shaped member 110 per unit length is non-uniform even in the tire circumferential direction.

The area center G1 of the first region 111 is the center of gravity of the first region 111. Similarly, the area center G2 of the second region 112 is the center of gravity of the second region 112.

In FIG. 3, the first region 111 and the second region 112 have a triangular shape. The center of gravity of the first region 111 and the center of gravity of the second region 112 can be easily calculated from the winding start position 110S and the winding end position 110E. The shape of the rubber member 100 developed on a flat surface can be obtained by taking an X-ray photograph or the like while rotating the tire 1.

As described above, when the strip-shaped member 110 is wound and cut at the winding start position as in Patent Document 1, the area center G1 of the first region 111 and the area center G2 of the second region are the tire circumferences. Since the deviation is 2/3 times in the direction, that is, the rotation angle is 240 ° (-120 °), the dynamic balance is deteriorated.

By the way, as an index showing the uniformity performance of the tire 1, static balance, dynamic balance, RFV (radial force variation) and the like can be mentioned. Of these, the dynamic balance is corrected by attaching weights to the rim. When the dynamic balance deteriorates, the weight required for correction increases, which affects not only the uniformity performance but also the appearance performance of the wheel.

Therefore, in the tire 1, the strip-shaped member 110 is wound so that the area center G1 of the first region 111 and the area center G2 of the second region 112 are arranged at substantially the same positions in the tire circumferential direction. More specifically, the strip-shaped member 110 is wound so that the area center G2 of the second region 112 exists in the range of 0 ± 15 ° around the tire axis with respect to the area center G1 of the first region 111. .. As a result, the area center G1 of the first region 111 and the area center G2 of the second region 112 are arranged at substantially the same position in the tire circumferential direction, so that the dynamic balance of the tire 1 is easily improved and the uniformity is achieved. Performance and appearance of wheels are improved.

From the above viewpoint, the amount of deviation of the tire shaft of the area center G2 of the second region 112 with respect to the area center G1 of the first region 111 is preferably in the range of 0 ± 10 °.

The alignment of the area center G1 of the first region 111 and the area center G2 of the second region 112 described above is realized by specifying the winding end position 110E with respect to the winding start position 110S of the strip-shaped member 110.

More specifically, the winding end position 110E of the strip-shaped member 110 is set at a position shifted by 240 ± 15 ° around the drum shaft with respect to the winding start position 110S. That is, in step S2, the strip-shaped member 110 ends winding and is cut at a position shifted by 240 ± 15 ° around the drum shaft with respect to the winding start position 110S. As a result, the area center G1 of the first region 111 and the area center G2 of the second region 112 are arranged at substantially the same position in the tire circumferential direction, and the dynamic balance of the tire 1 is easily improved. NS.

From the above viewpoint, the amount of rotation deviation of the tire shaft at the winding end position 110E with respect to the winding start position 110S of the strip-shaped member 110 is preferably in the range of 240 ± 10 °.

As shown in FIG. 3, the rubber member 100 includes an intermediate region 113 sandwiched between the first region 111 and the second region 112 in the tire axial direction. As shown in FIG. 4, in the intermediate region 113, the weight distribution of the strip-shaped member per unit length in the tire axial direction is uniform. As a result, the dynamic balance of the tire 1 is improved more easily.

It is desirable that the band-shaped member 110 is wound so that the rubber member 100 has a symmetrical shape with respect to the tire equator CL. As a result, the dynamic balance of the tire 1 is improved more easily.

It is desirable that the strip-shaped member 110 is wound at a pitch equal to that in the tire axial direction. As a result, the dynamic balance of the tire 1 is improved more easily.

FIG. 5 schematically shows a rubber member 100A which is a modification of the rubber member 100. FIG. 5 shows the weight distribution of the strip-shaped member 110 per unit length in the tire axial direction in the rubber member 100A.

The rubber member 100A differs from the rubber member 100 in that the strip-shaped member 110 is wound around the one end and the other end of the rubber member 100 in the tire circumferential direction. The above-described configuration of the rubber member 100 can be adopted for a portion of the rubber member 100A that is not described below.

In the rubber member 100A, the strip-shaped member 110 is wound around the tire circumferential direction from the winding start position 110S, and then is wound so as to be inclined in the tire circumferential direction. Then, after reaching the winding end position 110E, the tire is wound in the tire circumferential direction over one round, and then the winding ends. Therefore, in FIG. 5, the weights of the first region 111 and the second region 112 are added by one round of the strip-shaped member 110.

Similarly to the rubber member 100, the rubber member 100A also has a triangular first region 111 and a second region 112. The first region 111 and the second region 112 are regions in which the weight of the strip-shaped member 110 per unit length is non-uniform in the tire axial direction and the tire circumferential direction.

Also in the rubber member 100A, the strip-shaped member 110 is wound around the rubber member 100A so that the area center G1 of the first region 111 and the area center G2 of the second region 112 are arranged at substantially the same positions in the tire circumferential direction. The dynamic balance of the tire 1 is easily improved.

It is desirable that the tire 1 includes a plurality of rubber members 100. For example, it is desirable that the inner liner rubber 10 and the tread rubber 2G are composed of the rubber member 100. In this case, it is desirable that the winding start position 110S of the inner liner rubber 10 and the winding start position 110S of the tread rubber 2G are set at positions shifted by 180 ± 15 ° around the drum shaft. As a result, the area centers G1 and G2 of the inner liner rubber 10 and the area centers G1 and G2 of the tread rubber 2G are uniformly dispersed, and the static balance of the tire 1 is easily improved.

Further, the inner liner rubber 10, the tread rubber 2G and the band ply 9A may be composed of the rubber member 100. In this case, the winding start position 110S of the inner liner rubber 10, the winding start position 110S of the tread rubber 2G, and the winding start position 110S of the band ply 9A are displaced by 120 ± 15 ° around the drum shaft. It is desirable to set to. As a result, the area centers G1 and G2 of the inner liner rubber 10, the area centers G1 and G2 of the tread rubber 2G, and the area centers G1 and G2 of the band ply 9A are uniformly dispersed, and the static balance of the tire 1 is obtained. Is easily improved.

Further, in the case where the tread rubber 2G has a structure in which a plurality of layers such as a base layer and a cap layer are stacked, the tread rubber 2G is attached to the rubber member 100 constituting any one layer or all all layers. The invention may be applied. In this case, the static balance of the tire 1 is easily improved by dispersing the winding start position 100S of each rubber member 100.

Although the tire 1 of the present invention has been described in detail above, the present invention is not limited to the specific embodiment described above, but is modified to various embodiments.

100 tires having the basic structure of FIG. 1 and having a size of 265 / 65R17 were prototyped for each specification based on the specifications in Table 1, the dynamic balance was measured, and the average value was calculated. The rubber member whose winding start position and winding end position are changed is the inner liner rubber.

In Table 1, the amount of deviation of the inner liner rubber around the drum shaft at the winding end position with respect to the winding start position is represented by the overlap amount a1 (°). The amount of deviation between the area center of the first region and the area center of the second region of the inner liner rubber is represented by the phase difference a2 (°). The result is an index with Comparative Example 1 as 100, and the smaller the value, the better the dynamic balance performance.

As is clear from Table 1, it was confirmed that the tires of the examples had significantly improved dynamic balance performance as compared with the comparative examples.

Based on the specifications in Table 2, 100 tires were prototyped for each specification, the dynamic balance and static balance were measured, and the average value was calculated. The rubber member whose winding start position and winding end position are changed is the base layer of the inner liner rubber and the tread rubber.

In Table 2, the amount of deviation of the inner liner rubber around the drum shaft at the winding end position with respect to the winding start position is represented by the overlap amount a1 (°). The amount of deviation between the area center of the first region and the area center of the second region of the inner liner rubber is represented by the phase difference a2 (°).

The amount of deviation of the base layer around the drum shaft at the winding end position with respect to the winding start position is represented by the overlap amount b1 (°). The amount of deviation between the area center of the first region and the area center of the second region of the base layer is represented by the phase difference b2 (°).

The amount of deviation around the drum shaft at the winding start position of the base layer with respect to the winding start position of the inner liner rubber is represented by the phase difference c (°). The result is an index with Example 5 as 100, and the smaller the value, the better the dynamic balance performance and the static balance.

1 Tire 2G Tread rubber 9A Band ply 10 Inner liner rubber 100 Rubber member 100A Rubber member 101 One end 102 Other end 110 Band-shaped member 111 First area 112 Second area 113 Intermediate area 201 Drum 202 Outer circumference CL Tire equatorial line G1 Area center G2 area center

Claims (16)

Tire A tire containing a rubber member formed by spirally winding a band-shaped member from one side to the other side of the equator.
At one end of the rubber member in the tire axial direction, there is a first region in which the weight distribution of the strip-shaped member per unit length in the tire axial direction is non-uniform.
At the other end of the rubber member in the tire axial direction, there is a second region in which the weight distribution of the strip-shaped member per unit length in the tire axial direction is non-uniform.
When the rubber member is developed on a flat surface, the area center of the second region exists in the range of 0 ± 15 ° around the tire axis with respect to the area center of the first region. The winding start position of the strip-shaped member is arranged at the one end portion of the rubber member.
The tire according to claim 1, wherein the winding end position of the strip-shaped member is arranged at the other end of the rubber member. The tire according to claim 2, wherein the winding end position is displaced by 240 ± 15 ° with respect to the winding start position around the tire shaft. Any one of claims 1 to 3 in which the intermediate region sandwiched between the first region and the second region in the tire axial direction has a uniform weight distribution of the strip-shaped member per unit length in the tire axial direction. Tires listed in. The tire according to any one of claims 1 to 4, wherein the band-shaped member is wound so that the rubber member has a symmetrical shape with respect to the equator of the tire. The tire according to any one of claims 1 to 5, wherein the band-shaped member is wound at a pitch equal to that in the tire axial direction. The tire according to any one of claims 1 to 6, wherein the band-shaped member is wound around the one end portion of the rubber member and the other end portion of the rubber member so as to be inclined with respect to the tire circumferential direction. The band-shaped member according to any one of claims 1 to 6, wherein the band-shaped member is wound in the tire circumferential direction at the one-sided edge portion of the rubber member and the other-side edge portion of the rubber member. tire. The tire according to any one of claims 1 to 8, wherein the first region and the second region are triangular when the rubber member is developed on a flat surface. The tire according to any one of claims 1 to 9, which includes the plurality of rubber members. The tire according to claim 10, wherein the center of the area of the first region of the strip-shaped member constituting each rubber member is deviated in the tire circumferential direction. The tire according to claim 10 or 11, wherein the area center of the second region of the strip-shaped member constituting each rubber member is deviated in the tire circumferential direction. The tire according to any one of claims 10 to 12, wherein the rubber member includes an inner liner rubber. The tire according to any one of claims 10 to 13, wherein the rubber member includes a tread rubber. The tire according to any one of claims 10 to 14, wherein the rubber member includes a band ply whose band cord is covered with a topping rubber. A method of forming a rubber member for a tire by spirally winding a band-shaped member around the outer peripheral surface of the drum.
The step of starting winding the strip-shaped member from the winding start position of one end in the drum axial direction, and
Including a step of winding the strip-shaped member at the winding end position of the other end in the drum axial direction.
The winding end position is offset by 240 ± 15 ° around the drum axis with respect to the winding start position.
Rubber member forming method.

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