JP7241621B2 - Aircraft pneumatic tire - Google Patents

Description

The present invention relates to a pneumatic tire for aircraft.

A conventional aircraft pneumatic tire (for example, the aircraft radial tire described in Patent Document 1) includes a pair of bead cores and a radial carcass having at least one carcass ply extending toroidally between the bead cores. A belt layer is provided as a tread reinforcing member radially outside the radical carcass.

This belt layer includes a spirally wound belt layer in which a ribbon-shaped strip material in which a belt cord made of organic fibers is coated with rubber is wound in a substantially circumferential direction, and a belt made of organic fibers is wrapped around the outer circumference of the spirally wound belt layer. It consists of a zigzag belt layer in which a ribbon-shaped strip material in which a cord is covered with rubber is wound at an angle with respect to the tire equatorial plane, and is wound while being folded back at both ends in the width direction of the belt layer. .

At both ends of the zigzag belt layer in the width direction, the strip material is folded back in a zigzag pattern, so that there is a localized portion where there is only one layer instead of two interlaced layers of the strip material. Since a rigid step is formed at the boundary between the two-layer portion and the one-layer portion, a large strain is applied to the one-layer portion when the end portion of the belt is stretched.

Therefore, in order to secure the durability of the belt cord, it is necessary to make the strain of the zigzag belt layer smaller than the strain of the spirally wound belt layer. As a method for that purpose, making the width of the spirally wound belt layer wider than the width of the zigzag belt layer has been considered, and a technique such as that disclosed in Patent Document 1 has been conventionally studied.

However, when the width of the spirally wound belt layer is made wider than the width of the zigzag belt layer, there are the following problems.

When a load is applied to the tire and the zigzag belt layer is stretched in the circumferential direction, the strip material forming the zigzag belt layer is deformed into a pantograph shape. At the turning point, the tire moves inward in the width direction.

On the other hand, when the spirally wound belt layer is stretched in the circumferential direction, only the cords of the strip material are stretched, and movement in the tire width direction does not occur.

Therefore, a large shear strain occurs between the spirally wound belt layer and the zigzag belt layer. Aircraft tires, in particular, are used under high internal pressure and high load, so this tendency is significant. As a result, the crack progressed and the belt separation caused the tire to become inoperable.

JP 2008-114841 A

The present invention prevents the occurrence of cracks between the spirally wound belt layer and the zigzag belt layer in an aircraft pneumatic tire having a belt layer composed of a spirally wound belt layer and a zigzag belt layer, thereby preventing separation of the belt layers. The purpose is to prevent it and improve the durability of the tire.

In order to achieve the above object, the present invention provides a radial carcass having a pair of bead cores, one or more carcass plies extending toroidally between the bead cores, and a radial carcass disposed on the outer peripheral side of the crown region of the radial carcass. and a belt layer that reinforces the radial carcass, wherein the belt layer comprises a ribbon-shaped first belt cord made of organic fibers covered with a first covering rubber. A first strip material is spirally wound, a spirally wound belt layer in which a plurality of specified layers are superimposed, and a second belt cord made of organic fiber is covered with a second coating rubber. A second ribbon-shaped strip material is wound around the outer peripheral side of the spirally wound belt layer while extending in the circumferential direction while being folded back at the edges in the width direction and bent in a zigzag shape, A pneumatic tire for an aircraft, comprising: a zigzag belt layer in which a plurality of specified layers are superimposed; and a rubber member disposed between the spirally wound belt layer and the zigzag belt layer. is.

Since the present invention is configured as described above, the shear force between the spirally wound belt layer and the zigzag belt layer generated by the movement of the zigzag belt layer inward in the tire width direction can be The elastic deformation of the rubber member disposed between the belt layers can absorb the vibration, thereby preventing the generation of cracks between the spirally wound belt layer and the zigzag belt layer and preventing the separation of the belt layers. , the durability of the tire can be improved by preventing the failure of the belt layer in the tire width direction.

In the above configuration, the rubber member may be present in a range of 1% or more and 15% or less from the edge of the spirally wound belt layer with respect to the maximum width of the spirally wound belt layer.

According to the above configuration, when the tire receives a load and the belt cords of the zigzag belt layer are deformed into a pantograph shape, the spirally wound belt layer and the zigzag belt layer are located at the edge in the tire width direction where the amount of movement of the zigzag belt layer is the largest. By shearing deformation of the rubber member disposed between the belt layers, cracks between the spirally wound belt layer and the zigzag belt layer can be prevented, and separation of the belt layers can be further prevented, thereby increasing tire durability. can improve sexuality.

In the above configuration, the width of the rubber member in the tire width direction may be in the range of 5% or more and 15% or less of the maximum width of the spirally wound belt layer.

According to the above configuration, the rubber member disposed between the spirally wound belt layer and the zigzag belt layer can be made to have a necessary and sufficient width, and cracks in the rubber between the spirally wound belt layer and the zigzag belt layer can be prevented. Therefore, it is possible to further prevent separation of the belt layers and reduce an increase in the weight of the tire.

The said structure WHEREIN: The shape of the said rubber member can also be made into a long rubber sheet.

According to the above configuration, the rubber member can be easily arranged between the spirally wound belt layer and the zigzag belt layer.

In the above configuration, the thickness of the rubber member may be in the range of 0.5 mm or more and 3.0 mm or less.

According to the above configuration, since the thickness of the rubber member between the spirally wound belt layer and the zigzag belt layer is sufficiently secured, cracking of the rubber between the spirally wound belt layer and the zigzag belt layer can be prevented. In addition, it is possible to prevent separation of the belt layer, improve the durability of the tire, and prevent an increase in the weight of the tire as a whole .

In the above configuration, a rubber material having an elastic modulus lower than the elastic modulus of the first covering rubber and the elastic modulus of the second covering rubber may be used as the rubber member.

According to the above configuration, since the elastic modulus of the rubber member is lower than the elastic modulus of the first covering rubber and the elastic modulus of the second covering rubber, shear generated between the spirally wound belt layer and the zigzag belt layer is reduced. The force is mainly used for shear deformation of the rubber member. Therefore, cracks between the spirally wound belt layer and the zigzag belt layer are prevented, shear deformation of the first covering rubber and the second covering rubber is reduced, the belt cord is prevented from being cut, and the belt layer is can increase the strength of the tire and further improve the durability of the tire.

The aircraft pneumatic tire of the present invention prevents the occurrence of cracks between the spirally wound belt layer and the zigzag belt layer in an aircraft pneumatic tire equipped with a belt layer consisting of a spirally wound belt layer and a zigzag belt layer, It is possible to prevent the separation of the belt layer and improve the durability of the tire.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view in the width direction of a pneumatic tire for aircraft according to a first embodiment of the present invention assembled on a specified rim and having a specified internal pressure; FIG. 2 is an enlarged widthwise cross-sectional view of a main portion of one side of the aircraft pneumatic tire of FIG. 1 ; FIG. 4 is a partial development view showing an example of formation of a spirally wound belt layer; FIG. 4 is a partial development view showing an example of formation of a zigzag belt layer;

An embodiment of a pneumatic tire 1 for aircraft according to the present invention will be described with reference to FIGS. 1 to 4. FIG. FIG. 1 shows a cross-sectional view in the tire width direction of a pneumatic tire 1 for aircraft (hereinafter referred to as tire 1) according to an embodiment of the present invention. The tire 1 is mounted on the applicable rim 40.

In the drawing, the symbol CL corresponds to the center in the tire width direction and indicates the tire equatorial plane, which is a plane perpendicular to the tire rotation axis. The tire width direction is a direction parallel to the tire rotation axis, and the tire radial direction is a direction perpendicular to the tire rotation axis, toward or away from the tire rotation axis.

The tire 1 includes a bead portion 5 in which a pair of left and right ring-shaped bead cores 6 are embedded, a radial carcass 7 that extends between the pair of bead cores 6 in a toroidal shape, and a radially outward circumferential contact with the radial carcass 7. a tread portion 3 having a tread rubber 38 in contact with the outer peripheral surface of the belt layer 10; and a sidewall portion 4 covering the side portion of the tire 1. - 特許庁

The radial carcass 7 is formed by stacking one or more carcass plies 7a. rolled up and fixed. In the tire 1 of the present embodiment, seven carcass plies 7a made of nylon cords are stacked.

A belt layer 10 that reinforces the radial carcass 7 is provided outside in the tire radial direction on the outer peripheral side of the crown region 7b of the radial carcass 7 . The belt layer 10 includes a spirally wound belt layer 20 wound around the outer peripheral surface of the radial carcass 7, a zigzag belt layer 30 superimposed on the outer periphery of the spirally wound belt layer 20, and between the spirally wound belt layer 20 and the zigzag belt layer 30. A rubber member 15 provided and a protective belt layer 37 wound around the outer periphery of the zigzag belt layer 30 are provided. A tread rubber 38 is attached to the outer peripheral surface of the protective belt layer 37 to form the tread portion 3 . Both edges of the belt layer 10 in the width direction are defined as width direction edges 10a.

As shown in FIGS. 3 and 4, the spirally wound belt layer 20 and the zigzag belt layer 30 have a spirally wound strip 26 as a ribbon-like first strip material and a zigzag winding as a second strip material, respectively. A strip 36 is wound in a predetermined manner. The spiral winding strip 26 is formed by arranging a plurality of first belt cords 26a made of organic fibers and covering them with a first covering rubber 26b to form a ribbon having a predetermined width. The zigzag winding strip 36 is formed by arranging a plurality of second belt cords 36a made of organic fibers and covering them with a second covering rubber 36b to form a ribbon having a predetermined width.

The organic fiber belt cords 26a and 36a used for the spiral winding strip 26 and the zigzag winding strip 36 are organic fiber cords made of aromatic polyamide such as aramid. Alternatively, hybrid fiber cords made from combinations of aromatic polyamides and aliphatic polyamides such as nylon can be used.

The hybrid cord of the aliphatic polyamide fiber and the aramid fiber may be obtained by twisting the yarn made of the aliphatic polyamide fiber and the yarn made of the aramid fiber. It may be twisted.

The number of belt cords 26a of the spirally wound strip 26 is preferably in the range of 2 to 6, but is set to 4 in this embodiment. The width of the spirally wound strip 26 is preferably in the range of 3.0 mm to 9.0 mm, but is set to 6.0 mm in this embodiment. The interval between the belt cords 26a of the spirally wound strip 26 is preferably in the range of 1.1 to 2.0 times the diameter of the belt cords 26a. The belt cord 26a of the spirally wound strip 26 is, for example, a hybrid cord made of aramid and nylon.

The number of belt cords 36a of the zigzag winding strip 36 is preferably within the range of 7 to 11, but is set to 9 in this embodiment. The width of the zigzag winding strip 36 is preferably in the range of 6.0 mm to 18.0 mm, but is set to 13.0 mm in this embodiment. The interval between the belt cords 36a of the zigzag winding strip 36 is preferably in the range of 1.1 to 2.0 times the diameter of the belt cords 36a. A hybrid cord made of aramid and nylon, for example, is used for the belt cord 36a.

As shown in FIGS. 1, 2 and 3, the spirally wound belt layer 20 of the tire 1 is formed by spirally winding the spirally wound strip 26 as described above in the crown region 7b of the radial carcass 7 of the raw tire. It is a structured structure. The spirally wound belt layer 20 is shifted by a predetermined amount in the tire width circumferential direction so that the spirally wound strips 26 do not form gaps between the adjacent spirally wound strips 26 in the tire circumferential direction. Formed by rolling.

As shown in FIGS. 1 and 2, the helically wound strip 26 is wound up to the widthwise edge 20a of the helically wound belt layer 20 and then folded back to form the second layer 22 on the outer peripheral surface of the first layer 21. is wound toward the other edge 20a in the width direction, sequentially folded back and stacked, and the first layer 21, the second layer 22, and the third layer 23 of the spirally wound belt layer 20 are laminated. go.

The spiral winding strip 26 is wound with the belt cord 26a at a predetermined angle with respect to the tire equatorial plane CL. In this embodiment, the spiral winding strip 26 is wound so that the belt cord 26a is at an angle of 5° or less with respect to the tire equatorial plane CL. When the helical winding strip 26 starts winding around the crown region 7b of the radial carcass 7, the winding starts from the position of the widthwise edge 10a of the belt layer 10 in the tire width direction. The number of laminations of the spirally wound belt layer 20 is preferably within the range of 1 to 5. In the present embodiment, from the inner side in the tire radial direction, the first layer 21, the second layer 22, the third layer 23, is composed of three layers.

As shown in FIG. 1, a rubber member 15 made of a strip-shaped sheet having a predetermined width is attached to the outer peripheral surface of each of the edges 20a on both sides in the tire width direction of the spirally wound belt layer 20 in the circumferential direction. wrapped around. The shape of the rubber member 15 is a long rubber sheet, and the thickness of the rubber member 15 is in the range of 0.5 mm or more and 3.0 mm or less. The rubber member 15 is arranged so as to be positioned within a range of 1% or more and 15% or less of the maximum width Ws of the spirally wound belt layer 20 from the edge 20a of the spirally wound belt layer 20. As shown in FIG. The rubber member width Wg of the predetermined width of the rubber member 15 is set to be in the range of 5% or more and 15% or less of the maximum width Ws of the spirally wound belt layer 20 .
As the material for the rubber member 15, a rubber material having an elastic modulus smaller than that of the first covering rubber 26b of the spiral winding strip 26 and the elastic modulus of the second covering rubber 36b of the zigzag winding strip 36 is used. be done.

As shown in FIGS. 1 and 4, the zigzag belt layer 30 is constructed by winding a zigzag winding strip 36 around the spiral belt layer 20 and the rubber member 15 in a predetermined manner. The zigzag winding strip 36 is wound over the spirally wound belt layer 20 such that its maximum width We is less than the maximum width Ws of the spirally wound belt layer 20 .

As shown in FIG. 4, the zigzag belt layer 30 extends in the circumferential direction while a zigzag winding strip 36 is folded back at a predetermined widthwise edge 30a of the zigzag belt layer 30 and bent in a zigzag shape. It is a structure that exists and is wound. The zigzag winding strips 36 are wound with a desired amount of offset in the circumferential direction so that there is no gap between adjacent zigzag winding strips 36 .

The belt cord 36a of the zigzag winding strip 36 extends at an angle of 5° to 30° with respect to the tire equatorial plane CL up to folding points 36c folded at both width direction edges 30a of the zigzag belt layer 30. As present, the zigzag winding strip 36 is wound.

The zigzag belt layer 30 is made up of a specified number of layers, and in this embodiment, as shown in FIG. are superimposed, but can be changed as appropriate.

As described above, the spirally wound belt layer 20, the rubber member 15, and the zigzag belt layer 30 are wound around the radial outer side of the crown region 7b of the radial carcass 7, and the protective belt layer 37 and the tread rubber 38 are further wound around the outer peripheral surface thereof. The tire 1 of the present embodiment is obtained by vulcanizing and molding the raw tire after manufacturing the raw tire so as to be in a flat state.

The tire 1 of this embodiment is constructed as described above, and the rubber member 15 is disposed between the spirally wound belt layer 20 and the zigzag belt layer 30 in the vicinity of the edge 20a of the spirally wound belt layer 20. Therefore, the shearing force between the spirally wound belt layer 20 and the zigzag belt layer 30 is absorbed by the shearing deformation of the rubber member 15 to prevent the occurrence of cracks between the spirally wound belt layer 20 and the zigzag belt layer 30. can be done. Furthermore, the separation between the spirally wound belt layer 20 and the zigzag belt layer 30 can be prevented, the strength of the belt layer 10 can be increased, and the durability of the tire 1 can be improved.

The strength of the belt cord after running on the drum was tested as follows for each of the example tire having the configuration described above and a size of 52×22.0R22 and the tire of the conventional example. . A simulation was performed using a model simulating the tire 1, and the distortion of the rubber near the cord at the end of the belt was calculated.

From the results of such tests, the rubber member 15 is present in the range of 1% or more and 15% or less from the edge 20a of the spirally wound belt layer 20 with respect to the maximum width Ws of the spirally wound belt layer 20. It was found that cracks between the spirally wound belt layer 20 and the zigzag belt layer 30 are prevented, separation of the belt layers is further prevented, and tire durability is improved.

Further, when the rubber member width Wg of the rubber member 15 in the tire width direction is in the range of 5% or more and 15% or less of the maximum width Ws of the spirally wound belt layer 20, the spirally wound belt layer 20 and the zigzag belt The rubber member 15 disposed between the layer 30 can be made to have a necessary and sufficient width, preventing the rubber from cracking between the spirally wound belt layer 20 and the zigzag belt layer 30, and further separating the belt layers. It has been found that it is possible to prevent this and reduce the increase in the weight of the tire.

Although the embodiments of the present invention have been described above, it goes without saying that the aspects of the present invention are not limited to the above-described embodiments, and include those implemented in various aspects within the scope of the gist of the present invention.

DESCRIPTION OF SYMBOLS 1... Pneumatic tire for aircraft, 3... Tread part, 4... Side wall part, 5... Bead part, 6... Bead core, 7... Radial carcass, 7a... Carcass ply, 7b... Crown region,
10... belt layer, 10a... width direction edge, 15... rubber member,
20... spirally wound belt layer, 21... first layer, 22... second layer, 23... third layer, 26... strip for spiral winding, 26a... belt cord, 26b... first covering rubber,
30 Zigzag belt layer 30a Width direction edge 31 First layer 32 Second layer 33 Third layer 34 Fourth layer 36 Zigzag winding strip 36a Belt cord 36b ... second covering rubber, 36c ... turning point, 37 ... protective belt layer, 38 ... tread rubber,
40 ... applicable rim,
CL... tire equatorial plane, Ws... maximum width of spiral wound belt layer, We... maximum width of zigzag belt layer, Wg... width of rubber member.

Claims (4)

a pair of bead cores (6);
a radial carcass (7) having one or more carcass plies (7a) extending toroidally between the bead cores (6);
A pneumatic tire for aircraft comprising: a belt layer (10) disposed on the outer peripheral side of the crown region of the radial carcass (7) and reinforcing the radial carcass (7);
The belt layer (10) is
A ribbon-shaped first strip material (26) in which a first belt cord (26a) made of organic fiber is covered with a first covering rubber (26b) is spirally wound, a spirally wound belt layer (20) in which a plurality of layers (21, 22, 23,) are stacked;
A ribbon-shaped second strip material (36) in which a second belt cord (36a) made of organic fibers is coated with a second coating rubber (36b) is provided on the outer peripheral side of the spirally wound belt layer (20). It is a structure in which a plurality of prescribed layers (31, 32, 33, 34) are overlapped and wound in a circumferential direction while being folded back at the width direction edge (30a) and bent in a zigzag shape. a zigzag belt layer (30) applied to the
A rubber member (15) is disposed between the spiral belt layer (20) and the zigzag belt layer (30) ,
A pneumatic tire for aircraft , wherein the thickness of the rubber member (15) is in the range of 0.5 mm or more and 3.0 mm or less . The rubber member (15) is 1% or more and 15% or less of the maximum width (Ws) of the spiral belt layer (20) from the edge (20a) of the spiral belt layer (20). A pneumatic tire according to claim 1, characterized in that it lies in a range. The width (Wg) of the rubber member (15) in the tire width direction is in the range of 5% or more and 15% or less of the maximum width (Ws) of the spiral belt layer (20). The pneumatic tire for aircraft according to claim 1 or 2. The pneumatic tire for aircraft according to any one of claims 1 to 3, wherein the rubber member (15) has a shape of a long rubber sheet.

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