JP7419840B2 - Tire and rubber member forming method - Google Patents

Description

The present invention relates to a tire with a jointless structure formed by spirally wrapping a band member.

BACKGROUND ART Tires have been known that have improved uniformity performance by spirally wrapping a strip member. For example, Patent Document 1 discloses a tire in which the static balance is improved by setting the deviation in the tire circumferential direction between the winding start position and the winding end position to 0 to 5 mm.

Japanese Patent Application Publication No. 2002-178415

In the tire shown in Patent Document 1, a winding start position and a winding end position are arranged at both ends in the axial direction of the rubber member, and the band-like member is wound at an angle with respect to the tire circumferential direction. Therefore, regions are created at both axial ends of the rubber member where the weight distribution of the band-like member per unit length in the tire axial direction is non-uniform.

However, as mentioned above, when the deviation in the tire circumferential direction between the winding start position and the winding end position is 0 to 5 mm, the center of gravity at one end of the rubber member in the axial direction and the center of gravity at the other end of the rubber member in the axial direction Dynamic balance deteriorates because the tire and tire are shifted in the circumferential direction of the tire.

The present invention was devised in view of the above-mentioned circumstances, and its main purpose is to provide a technique for improving dynamic balance in a tire with a jointless structure.

A first aspect of the present invention is a tire including a rubber member formed by winding a band-like member spirally from one side of the tire equator to the other side, the rubber member having one end in the tire axial direction. , has a first region in which the weight distribution of the band-like member per unit length in the tire axial direction is uneven, and has a first region in which the weight distribution per unit length in the tire axial direction is The band-like member has a second region in which the weight distribution is uneven, and when the rubber member is developed on a flat surface, the center of area of the second region is at the center of the tire axis with respect to the center of area of the first region. It exists within a range of 0±15° around the circumference.

In the tire according to the present invention, a winding start position of the band-like member is arranged at the one end of the rubber member, and a winding end position of the band-like member is arranged at the other end of the rubber member. This is desirable.

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

In the tire according to the present invention, an intermediate region sandwiched between the first region and the second region in the axial direction of the tire has a uniform weight distribution of the band member per unit length in the axial direction of the tire. This is desirable.

In the tire according to the present invention, it is preferable that the band member is wound such that the rubber member has a symmetrical shape with respect to the tire equator.

In the tire according to the present invention, it is preferable that the band-like member is wound at equal pitches in the tire axial direction.

In the tire according to the present invention, it is preferable that the band member is wound around the one end of the rubber member and the other end of the rubber member at an angle with respect to the tire circumferential direction.

In the tire according to the present invention, it is preferable that the band-shaped member is wound in the tire circumferential direction at the one end edge of the rubber member and the other end edge of the rubber member. .

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

The tire according to the present invention preferably includes a plurality of the rubber members.

In the tire according to the present invention, it is preferable that the center of area of the first region of the band member constituting each rubber member is shifted in the tire circumferential direction.

In the tire according to the present invention, it is preferable that the center of area of the second region of the band member constituting each rubber member is shifted in the tire circumferential direction.

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

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

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

A second invention of the present invention is a method of forming a rubber member for a tire by spirally wrapping a band-like member around the outer peripheral surface of a drum, the band-like member being wound from a winding start position at one end in the axial direction of the drum. The steps include the step of starting winding, and the step of finishing winding the strip member at a winding end position at the other end in the drum axis direction, and the winding end position is 240±15 degrees around the drum axis with respect to the winding start position. It's off by ゜.

In the tire of the first aspect of the present invention, when the rubber member is developed on the plane, the center of area of the first region and the center of area of the second region are substantially at the same position in the tire circumferential direction. Allotted. Thereby, the dynamic balance of the tire is easily improved and the uniformity performance is improved.

In the method for forming a rubber member according to the second aspect of the present invention, the band-like member finishes 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 area where the weight distribution is uneven at the one end of the rubber member, and the area center of the second area where the weight distribution is uneven at the other end of the rubber member. are arranged at substantially the same position in the circumferential direction of the tire. Thereby, the dynamic balance of the tire is easily improved and the uniformity performance is improved.

1 is a sectional view showing one embodiment of a tire of the present invention. 2 is a diagram schematically showing a forming apparatus and method for forming a rubber member used in the tire of FIG. 1. FIG. FIG. 3 is a diagram schematically showing a rubber member developed on a plane. FIG. 4 is a diagram showing the weight distribution of a band-like member that constitutes the rubber member of FIG. 3; 4 is a diagram schematically showing a modification of the rubber member shown in FIG. 3. FIG. FIG. 6 is a diagram showing the weight distribution of a band-like member that constitutes the rubber member of FIG. 5;

Hereinafter, one embodiment of the present invention will be described based on the drawings.
FIG. 1 shows a meridional section of a tire 1 according to the present embodiment, including the tire shaft.

The tire 1 of the present embodiment includes a toroidal carcass 6 that extends over a pair of bead portions 4 via a tread portion 2 and a pair of sidewall portions 3, and a toroidal carcass 6 disposed on the outside of the carcass 6 of the sidewall portion 3 in the tire axial direction. Includes sidewall rubber 3G.

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

A "regular rim" is a rim specified for each tire by the standard in the standard system including the standard on which Tire 1 is based, for example, "Standard rim" for JATMA, "Design Rim" for TRA, For ETRTO, it is "Measuring Rim".

A normal state is defined as an unloaded state in which the tire 1 is mounted on a regular rim R and is filled with a regular internal pressure. "Regular internal pressure" is the air pressure specified for each tire by each standard in the standard system including the standard on which the tire is based, and for JATMA it is the "maximum air pressure", and for TRA it is the air pressure specified in the table "TIRE LOAD LIMITS". The maximum value described in "AT VARIOUS COLD INFLATION PRESSURES" is "INFLATION PRESSURE" for ETRTO. When the tire is for a passenger car, the normal internal pressure is, for example, 180 kPa. Hereinafter, unless otherwise specified, the dimensions of each part of the tire are values measured under this normal condition.

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

The belt layer 7 is composed of two or more belt plies 7A and 7B, in this example two belt plies 7A and 7B, in which belt cords are arranged at an angle of, for example, 15 to 45 degrees with respect to the tire circumferential direction. For example, steel, aramid, rayon, or the like is preferably used for the belt cord. Belt plies 7A and 7B are constructed by covering a plurality of belt cords with topping rubber. The belt plies 7A and 7B are laminated and the cords cross each other between the plies, thereby reinforcing the tread portion 2 with high rigidity.

On the outside of the belt layer 7 in the tire radial direction, a band layer 9 made of a band ply 9A formed by spirally winding a band cord in the circumferential direction is provided for the purpose of improving high-speed durability and handling stability. In this example, organic fibers such as nylon are preferably used for the band cord. Band layer 9 may be omitted.

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

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

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

FIG. 2 schematically shows an apparatus and method for forming the rubber member 100. The forming device 200 includes a drum 201 around which the strip member 110 is wound, and an applicator 210 for supplying the strip 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 its axial direction. Moreover, 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 supply device may be applied to the applicator 210. For example, the applicator 210 may be constituted by a device including a belt for conveying the strip member 110 and a roller for pressing the wound portion of the strip member 110 inward in the radial direction of the drum 201.

The rubber member 100 is formed by winding the band 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 of the drum equator to the other side. As a result, a rubber member 100 is formed that straddles the tire equator CL and extends from one side of the tire equator CL to the other side.

FIG. 3 schematically shows the rubber member 100 developed in a plane. 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 respect to the winding start position 110S of the band member 110 as a reference (0°) is shown in the vertical direction. . Referring to FIGS. 2 and 3, the method for forming the rubber member 100 includes a step S1 in which the band-like member 110 is started from a winding start position 110S at one end 101, and a step S1 where the band-like member 110 is wound at the winding end position 110E at the other end 102. and ending step S2.

FIG. 4 shows the weight distribution of the band member 110 per unit length in the tire axial direction. In FIG. 4, the horizontal axis indicates the length in the tire axial direction, and the vertical axis indicates the weight of the band member 110 per unit length.

In the forming device 200, the drum 201 is rotated to move the applicator 210 in the axial direction of the drum 201, so the band 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 band-like member 110 per unit length in the tire axial direction is uneven at both ends of the rubber member 100 in the tire axial direction (in other words, A first region 111 and a second region 112 (the weight of the band member 110 per unit length in the tire axial direction is not constant) are generated.

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

The area center G1 of the first region 111 becomes the center of gravity of the first region 111. Similarly, the area center G2 of the second region 112 becomes 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. Note that the shape of the rubber member 100 developed on a plane can be obtained by taking an X-ray photograph or the like while rotating the tire 1.

As already mentioned, when the strip 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 aligned with the tire circumference. Since the rotation angle is shifted by 2/3 of a turn, that is, the rotation angle is shifted by 240 degrees (-120 degrees), the dynamic balance deteriorates.

By the way, as an index indicating the uniformity performance of the tire 1, static balance, dynamic balance, RFV (radial force variation), etc. can be mentioned. Of these, 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 wheels.

Therefore, in the present tire 1, the band-shaped member 110 is wound so that the center of area G1 of the first region 111 and the center of area G2 of the second region 112 are arranged at substantially the same position in the tire circumferential direction. More specifically, the strip member 110 is wrapped around the tire axis such that the center of area G2 of the second region 112 lies within a range of 0±15° with respect to the center of area G1 of the first region 111. . As a result, the center of area G1 of the first region 111 and the center of area 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 improved. The performance and appearance of the wheels are improved.

Further, from the above viewpoint, it is desirable that the amount of deviation around the tire axis of the area center G2 of the second region 112 with respect to the area center G1 of the first region 111 is 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 of the belt-like member 110 relative to the winding start position 110S.

More specifically, the winding end position 110E of the strip member 110 is set at a position shifted by 240±15° around the drum axis with respect to the winding start position 110S. That is, in the above step S2, the band member 110 is wound and cut at a position shifted by 240±15° around the drum axis from the winding start position 110S. As a result, the center of area G1 of the first region 111 and the center of area 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. Ru.

Further, from the above viewpoint, it is desirable that the rotational deviation amount of the tire axis between the winding end position 110E and the winding start position 110S of the band member 110 is in the range of 240±10°.

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

It is desirable that the band member 110 is wrapped around the rubber member 100 so that it has a symmetrical shape with respect to the tire equator CL. Thereby, the dynamic balance of the tire 1 can be improved even more easily.

It is desirable that the band member 110 is wound at equal pitches in the tire axial direction. Thereby, the dynamic balance of the tire 1 can be improved even more easily.

FIG. 5 schematically shows a rubber member 100A that is a modified example of the rubber member 100. FIG. 5 shows the weight distribution of the band 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 described above in that a band-like member 110 is wound in the tire circumferential direction at one end and the other end of the rubber member 100. For parts of the rubber member 100A that are not explained below, the configuration of the rubber member 100 described above may be adopted.

In the rubber member 100A, the band member 110 is wound around the tire circumferential direction from the winding start position 110S, and then is wound obliquely in the tire circumferential direction. Then, after reaching the winding end position 110E, the winding is completed after being wrapped in the tire circumferential direction for one round. Therefore, in FIG. 5, the weight of the first region 111 and the second region 112 is added by one circumference of the band member 110.

Similarly to the rubber member 100, a triangular first region 111 and a triangular second region 112 are formed in the rubber member 100A. The first region 111 and the second region 112 are regions in which the weight of the band member 110 per unit length is uneven in the tire axial direction and the tire circumferential direction.

Also in the rubber member 100A, the band member 110 is wound so that the center of area G1 of the first region 111 and the center of area G2 of the second region 112 are arranged at substantially the same position 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 constituted by 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 axis. Thereby, the area centers G1, G2 of the inner liner rubber 10 and the area centers G1, 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 constituted by 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 shifted by 120±15° around the drum axis. It is desirable to set it 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 distributed, and the static balance of the tire 1 is can be easily improved.

In addition, if 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 rubber member 100 constituting any layer or all the layers may have a main layer. The invention may be applied. In this case, by distributing the winding start positions 100S of each rubber member 100, the static balance of the tire 1 can be easily improved.

Although the tire 1 of the present invention has been described in detail above, the present invention is not limited to the above-described specific embodiments, but can be implemented with various modifications.

100 tires of size: 265/65R17 having the basic structure shown in FIG. 1 were prototyped for each specification based on the specifications shown 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 an inner liner rubber.

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

As is clear from Table 1, it was confirmed that the tire of the example had significantly improved dynamic balance performance compared to the comparative example.

100 of the above tires were trial-produced for each specification based on the specifications in Table 2, the dynamic balance and static balance were measured, and the average value was calculated. The rubber members whose winding start position and winding end position are changed are the inner liner rubber and the base layer of the tread rubber.

In Table 2, the amount of deviation around the drum axis between the winding start position and the winding end position of the inner liner rubber is expressed as the overlap amount a1 (°). The amount of deviation between the center of area of the first region and the center of area of the second region of the inner liner rubber is expressed as a phase difference a2 (°).

The amount of deviation around the drum axis between the winding start position and the winding end position of the base layer is expressed as an overlap amount b1 (°). The amount of deviation between the center of area of the first region and the center of area of the second region of the base layer is expressed as a phase difference b2 (°).

The amount of deviation around the drum axis between the base layer's winding start position and the inner liner rubber's winding start position is expressed as a phase difference c (°). The results are expressed as an index with Example 5 as 100, and the smaller the value, the better the dynamic balance performance and 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 member 111 First region 112 Second region 113 Intermediate region 201 Drum 202 Outer circumferential surface CL Tire equator G1 Center of area G2 center of area

Claims (16)

A tire including a rubber member formed by a band-like member spirally wound from one side of the tire equator to the other side,
A first region is provided at one end of the rubber member in the tire axial direction, where the weight distribution of the band-like member per unit length in the tire axial direction is uneven;
The rubber member has a second region at the other end in the tire axial direction in which the weight distribution of the band-like member per unit length in the tire axial direction is uneven;
When the rubber member is developed on a plane, the center of area of the second region is within a range of 0±15° around the tire axis with respect to the center of area of the first region. The winding start position of the band-like member is arranged at the one end of the rubber member,
The tire according to claim 1, wherein a winding end position of the band member is located at the other end of the rubber member. The tire according to claim 2, wherein the winding end position is offset from the winding start position by 240±15° around the tire axis. Any one of claims 1 to 3, wherein an intermediate region sandwiched between the first region and the second region in the tire axial direction has a uniform weight distribution of the band-like 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 member is wound so that the rubber member has a symmetrical shape with respect to the tire equator. The tire according to any one of claims 1 to 5, wherein the band member is wound at an equal pitch 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 of the rubber member and the other end of the rubber member at an angle with respect to the tire circumferential direction. 7. The belt-shaped member is wound in the tire circumferential direction at the one end edge of the rubber member and the other end edge of the rubber member. tire. The tire according to any one of claims 1 to 8, wherein the first region and the second region have a triangular shape when the rubber member is developed flatly. The tire according to any one of claims 1 to 9, comprising a plurality of the rubber members. The tire according to claim 10, wherein the center of area of the first region of the belt-like member constituting each rubber member is shifted in the tire circumferential direction. The tire according to claim 10 or 11, wherein the center of area of the second region of the band-like member constituting each rubber member is shifted in the tire circumferential direction. The tire according to any one of claims 10 to 12, wherein the rubber member includes inner liner rubber. The tire according to any one of claims 10 to 13, wherein the rubber member includes tread rubber. The tire according to any one of claims 10 to 14, wherein the rubber member includes a band ply in which a band cord is covered with topping rubber. A method of forming a rubber member for a tire by spirally wrapping a band-like member around the outer peripheral surface of a drum, the method comprising:
starting to wind the band member from a winding start position at one end in the axial direction of the drum;
finishing winding the band member at a winding end position at the other end in the axial direction of the drum;
The winding end position is shifted by 240±15° around the drum axis with respect to the winding start position.
Rubber member forming method.

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