JP6219754B2 - tire - Google Patents

Description

  The present invention relates to a tire, and more particularly to an aircraft tire including a belt with a cut end and a belt without a cut end.

2. Description of the Related Art As tires for aircraft, those using an endless belt (zigzag structure belt) and a belt without a cut end called a spiral belt are known (see Patent Document 1).
The belt without a cut end is a belt that is located at both ends in the width direction of the tire and that does not expose the cut ends of the organic fiber cords at both ends of the belt continuous in the circumferential direction of the tire.
However, for example, when the belt is constituted only by the belt layer without a cut end, the durability of the belt is improved, but the zigzag structure belt is required to return to the tire equatorial plane with a right-up slope and a left-up slope. On the tire cross section, two sheets are configured as one set, and even when odd sheets are sufficient, even sheets must be used, so the weight of the tire increases and the cost also increases.
Therefore, there is an aircraft tire configured using a belt with a cut end and a belt without a cut end.
The belt with a cut end is a belt that is located on both ends in the width direction of the tire and the cut ends of the organic fiber cords are exposed at both ends of the belt continuous in the circumferential direction of the tire.

JP 2012-1206 A

However, aircraft tires configured using a belt with a cut end and a belt without a cut end use a belt with a cut end, so stress concentration occurs at the cut end as a nucleus (starting point) and the temperature is high. There is concern about a decrease in durability due to separation that occurs in some cases.
The present invention provides a lightweight and durable tire for an aircraft, which is configured by using a belt with a cut end and a belt without a cut end.

In aircraft tires, wear at the center of the crown of the tire progresses due to the impact of the landing of the aircraft, and in areas where wear did not progress after the middle wear period, a lot of tread remains, so the contact length becomes longer and the temperature rises It is known that the deformation becomes large, but the range is that when the distance from the tire equatorial plane to the tire ground contact position in the tire width direction at the normal internal pressure / normal load of the new tire is the distance A. This is a region from the tire equator plane to a position 60% to 80% away from the distance A.
Accordingly, a tire according to the present invention includes a belt without a cut end, in which a cut end of an organic fiber cord is not exposed at a side end of a belt that is located on both ends in the width direction of the tire and continues in the circumferential direction of the tire, In a tire provided with a belt portion in which a cut end of an organic fiber cord is exposed at both ends of a belt located at both ends in the width direction of the belt and the cut ends of organic fiber cords are exposed. When the distance from the tire equator to the tire ground contact position in the width direction of the tire at normal internal pressure and load is distance A, the center position in the tire width direction of the belt with the cut end coincides with the tire equator plane. tire widthwise end position of the belt there the cut end placed by is provided from the equatorial plane of the tire more than 90% away in the distance a, and the distance from the equatorial plane of the tire A belt with a cut end provided on the outer side in the radial direction of the tire than a belt with a cut end provided at a position 90% or more of the belt, and the end position in the tire width direction of the belt with the other cut end is by from the equatorial plane to constitute the tire so that provided at a position closer to the equatorial plane of the tire than 40% away in the distance a, the cutting under the area where the ground length to wear after the middle period of the tire becomes longer Since the cut end, which is the end position in the tire width direction of the belt with end, is not positioned, it has a structure that can suppress the occurrence of separation with the cut end as the nucleus (starting point), and is lightweight and durable for aircraft it is possible to obtain a tire, base Yes (60% to 80% away region to the position of the distance a from the tire equatorial plane) cut end beneath the region where the ground contact length becomes longer to wear after the middle period of the tire Since the cutting edge is a tire widthwise end positions of the bets was prevented positioned, it becomes a structure in which the cut end can suppress the occurrence of separation of the core (origin), and can improve the pressure resistance of the crown portion of the tire .
The crossing angle between the organic fiber cord of the belt without a cut end and the equator plane of the tire is greater than 0 ° and 30 ° or less, and the crossing angle between the organic fiber cord of the belt with a cut end and the equator plane of the tire is 0 °. Since it is larger than 25 °, the pressure resistance performance is excellent, and the occurrence of separation with the cut end as a nucleus (starting point) can be suppressed, and a lightweight and highly durable tire for aircraft can be obtained.
If the diameter of the organic fiber cord cut end there belt φ in of al, the code distance between the cut end of the cut end there belt is made larger than 0.4Fai, can reduce the strain between codes, crack When it occurs, the progress of cracks between the cords can be suppressed.
Since the belt with a cut end is provided on the outer side of the tire in the radial direction of the belt without the cut end, the distance between the cut end and the carcass ply can be secured, and even if a crack occurs at the cut end, It becomes difficult to reach the ply, and safety can be secured.

Sectional drawing of a tire. The perspective view for demonstrating the shaping | molding method of an inner side belt. The expanded view for demonstrating the shaping | molding method of an inner side belt. Sectional drawing of an inner side belt. The figure which shows the cut end of an outer side belt. The figure which shows a performance test result.

  Hereinafter, the present invention will be described in detail through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims, and all combinations of features described in the embodiments are included in the invention. It is not necessarily essential to the solution, but includes a configuration that is selectively adopted.

  A pneumatic tire 1 according to the present embodiment (hereinafter referred to as a tire 1) is an aircraft tire and includes a carcass 2, a tread 3, and a belt portion as shown in FIG. . The belt portion is composed of an inner belt portion 4 and an outer belt portion 5.

The carcass 2 is configured by laminating a plurality of flat cord layers called plies (carcass plies) covered with rubber so that unillustrated cords formed of organic fibers are arranged in parallel.
The carcass 2 is disposed such that a plurality of cord layers laminated from the inner surface 11 side of the tire 1 toward the outer surface 12 side of the tire 1 straddle a pair of bead portions 21; The plurality of layers on the side are turn-up plies whose ends are folded back from the inside in the tire width direction to the outside with respect to the bead core 22 of the bead portion 21, and both ends of the plurality of layers on the outer layer side are the bead core 22 of the bead portion 21. On the other hand, it is a down ply that is folded back from the outside in the tire width direction.

  The tread 3 is disposed outside the carcass 2 in the tire radial direction. A plurality of circumferential main grooves 31 extending in the tire circumferential direction are formed on the surface of the tread 3.

The inner belt portion 4 is provided between the carcass 2 and the tread 3.
The inner belt portion 4 includes a single layer belt 41 or a plurality of layers of belts 41; 41... Laminated from the inner surface 11 side of the tire 1 toward the outer surface 12 side of the tire 1. The belt 41 is a belt without a cut end, that is, the cut end of the cord 43 (see FIG. 4) is exposed at both side ends of the belt located on both ends in the width direction of the tire 1 and continuing in the circumferential direction of the tire 1. Not a belt.

The ply (belt ply) forming the belt 41 of the inner belt portion 4 is, for example, an elongated continuous plate 42 in which a cord 43 formed of organic fiber is covered with rubber, as shown in FIG. The core) 46 is wound around the tire assembly drum 46 so as to reciprocate once between the side edges 45; 45 in the width direction of the tire assembly drum 46 every time it makes one round in the circumferential direction. It is formed by performing a large number of windings while shifting substantially by the width of the elongated continuous plate 42 in the circumferential direction so that no gap is generated between the elongated continuous plates 42. The elongated continuous plate 42 has a configuration in which a plurality of cords 43 are arranged in parallel to each other and covered with rubber so as to extend along the side edge surface 44 of the elongated continuous plate 42, or a single cord 43. Is formed by covering with rubber so as to extend along the side edge surface 44 of the elongated continuous plate 42.
The cord 43 in the belt 41 extends along the tire circumferential direction while changing the bending direction at the side end 45 in the width direction of the tire assembly drum 46 while zigzag, and is embedded substantially uniformly in the belt 41. .

Further, as described above, when the elongated continuous plate 42 is wound while being bent at a predetermined curvature radius R at both side ends 45; 45 in the width direction of the tire assembly drum 46, these bent portions, that is, the belt 41 Near the both ends, a substantially triangular region 47 in which half widths of the three elongated continuous plates 42 are vertically overlapped is repeatedly generated in the circumferential direction, and these regions 47 are successively stacked in the circumferential direction one after another. 48 (see FIG. 3; FIG. 4).
The belt configured as described above is called an endless belt (zigzag structure belt).

The outer belt portion 5 is provided between the inner belt portion 4 and the tread 3.
The outer side belt part 5 is provided with the belt 51 of 1 layer, or the multiple layers belt 51; 51A; 51B ... (refer FIG. 1) laminated | stacked toward the outer surface 12 side of the tire 1 from the inner surface 11 side of the tire 1. FIG. . The belts 51; 51A; 51B are cords 52 (see FIG. 5) at both ends of the belt with cut ends, that is, belts positioned at both ends in the width direction of the tire 1 and continuous in the circumferential direction of the tire 1. The cut end of the belt is exposed.
The belts 51; 51A; 51B... Of the outer belt portion 5 are configured by a flat cord layer called a ply (belt ply) covered with rubber so that the cords 52 formed of organic fibers are arranged in parallel.

Area of contact width in the width direction of the tire 1 at the time of normal internal pressure / normal load of a new tire (the area between the left and right tire contact end positions 15 in the tire width direction in FIG. 1; an area indicated by A + A) ), The contact length becomes longer after the middle stage of wear of the tire 1 because the distance from the tire equatorial plane 1A to the tire contact end position 15 in the tire width direction at the normal internal pressure / normal load of the new tire is the distance A. In this case, it is a region from the tire equatorial plane 1A to a position 60% to 80% away from the distance A, and the bending deformation increases under the region.
“Treating width in the width direction of the tire at normal internal pressure and normal load” means that the tire is filled with air pressure corresponding to the maximum load capacity in the applicable size and ply rating specified in TRA's AIRCRAFFT YEAR BOOK. The distance between the outermost ends in the tire width direction in the contact area when the maximum load capacity of the tire is applied. When the ETRTO standard is applied at the place of use or manufacturing, the respective standard is followed.

  Therefore, in the tire 1 of the embodiment, the tire 51 in the tire width direction end position 51e; 51f; 51g (the position of the cut end along the one circumferential direction of the tire) of the belt 51; 51A; After the middle stage of wear, the contact length was increased and the bending deformation was increased, so that the distance from the lower part of the region from the tire equatorial plane 1A to a position 60 to 80% away from the distance A was set.

  Specifically, among the plurality of belts 51; 51A; 51B... With cut ends, the belt is positioned closest to the inner belt portion 4, and the center position in the tire width direction of the belt is aligned with the tire equatorial plane 1A. The installed position 51e of the belt 51 in the tire width direction (the position of the cut end along the circumferential direction of the tire 1) is a distance A from the tire equatorial plane 1A (from the tire equatorial plane at normal internal pressure / normal load). The distance to the tire ground contact position in the width direction was 90% or more away.

Further, belts 51A; 51B (other belts with cut ends) other than the belt 51 located on the side closest to the inner belt part 4 are tire width direction end positions 51f; 51g (along the circumferential direction of the tire). The position of the cut end) is not positioned at a position away from the tire equatorial plane 1A by 40% or more of the distance A. That is, the end positions 51f; 51g of the belt 51A; 51B in the tire width direction are positioned closer to the tire equatorial plane 1A than the position B which is 40% of the distance A.
In addition, the tire width direction end position 41e of the inner belt portion 4 installed with the center position in the tire width direction of the belt and the tire equatorial plane 1A coincided with each other is located in the vicinity of the position away from the tire equatorial plane 1A by the distance A. Thus, for example, the tire 51 is positioned slightly closer to the tire equatorial plane 1A than the end position 51e of the belt 51 in the tire width direction.

According to the tire 1 of the embodiment, the tire width direction end positions 51e; 51f; 51g of the outer belt portion 5 have a longer contact length after the middle stage of wear of the tire 1, and the tire equatorial plane 1A from which bending deformation increases. Since it is set so as to be out of the region between the position 60% away from the distance A and the position 80% away from the tire equatorial plane 1A, the cut end of the outer belt portion 5 However, it becomes difficult to be affected by bending deformation, the occurrence of separation with the cut end of the outer belt portion 5 as a core can be suppressed, and the durability of the tire 1 can be improved.
Further, under the region between the position 60% of the distance A from the tire equator plane 1A and the position 80% of the distance A from the tire equator plane 1A, bending deformation increases and the temperature also increases. In the embodiment, since the cut end of the outer side belt portion 5 is located at a position deviating from the lower side of the region, it is difficult to be affected by the temperature and the deterioration of the durability of the tire 1 can be suppressed.

  Further, according to the tire 1 of the embodiment, the inner belt portion 4 is constituted by a belt without a cut end, and the outer belt portion 5 is constituted by a belt with a cut end. That is, since the belt with the cut end is provided on the outer side in the radial direction of the tire 1 than the belt without the cut end, the distance between the cut end and the carcass ply can be secured, and even if a crack occurs in the cut end, However, it becomes difficult to reach the carcass ply, and safety can be secured.

In the tire 1 according to the embodiment, the cord of the carcass 2, the cord 43 of the inner belt portion 4, and the cord 52 of the outer belt portion 5 are formed of an organic fiber such as nylon, for example, 66 nylon.
Further, the intersection angle between the cord of the carcass 2 and the tire equatorial plane 1A is configured to be in the range of 85 ° to 90 °.
Further, the intersection angle α (see FIG. 3) between the cord 43 of the inner belt portion 4 and the tire equatorial plane 1A (see FIG. 3) is preferably 10 ° to 30 ° so as to be larger than 0 ° and smaller than 30 °. Configured as follows.
Further, the crossing angle between the cord 52 of the outer side belt portion 5 and the tire equatorial plane 1A is configured to be 0 ° to 25 °, preferably 10 ° to 25 °.
As described above, the cord is formed of an organic fiber cord, and the intersection angle (cord angle) between the organic fiber cord and the tire equatorial plane 1A is configured as described above. It is possible to suppress the occurrence of separation with nuclei (starting point) as the core, and to obtain an aircraft tire 1 that is lightweight and excellent in durability.

Also, if the distance between the cords at the end position in the tire width direction of the belt with a cut end is made smaller than 0.4 φ of the cord diameter φ, the distortion between the cords at the end position in the tire width direction of the belt with a cut end When the crack is generated at the cut end, the crack is easily propagated between the cords and the cords.
Therefore, in the embodiment, as shown in FIG. 5, the adjacent cords 52 at the end positions (cut ends) (51e; 51f; 51g...) Of the belts with cut ends (51; 51A; 51B...) The interval w between 52 was set to be larger than 0.4φ when the diameter of the cord 52 was φ. As a result, the distortion between the cords at the end position in the tire width direction of the belt with a cut end can be reduced, and when a crack occurs at the cut end, the crack does not easily propagate between the cord and the cord. .

The result of testing the performance of the tire according to the embodiment is shown in FIG.
Test method;
(1) The tires of Comparative Examples 1 and 2 and Examples 1 and 2 were individually attached to an indoor drum having an outer diameter of 3 m, and the tires were run to failure under the following conditions, and the running distance until the failure was measured.
・ Internal pressure = 1520 Kpa, load = 254 KN.
・ The tread part is simulated to wear, and the tire center part is cut to a groove depth of 1 mm.
(2) The belt end was exposed so that the strain applied to the belt end could be visually observed, and the strain applied to the belt end was measured under the following conditions.
・ Internal pressure = 1520 Kpa, load = 254 KN.

The tires of Comparative Examples 1 and 2 and Examples 1 and 2 are a belt without a cut end (zigzag structure belt) and a belt with a cut end, which are installed such that the center position in the tire width direction of the belt coincides with the tire equatorial plane 1A. The belt with a cut end is provided on the outer side in the tire radial direction of the belt without a cut end.
The tire of Comparative Example 1 is a tire in which the end position in the tire width direction (belt end (cut end) position) of the belt with a cut end is provided at a position 80% of the distance A from the tire equatorial plane 1A. .
The tire of Comparative Example 2 is a tire in which the end position in the tire width direction (belt end (cut end) position) of the belt with a cut end is provided at a position that is 85% of the distance A from the tire equatorial plane 1A.
The tire of Example 1 is a tire in which the end position in the tire width direction (belt end (cut end) position) of the belt with a cut end is provided at a position 90% of the distance A from the tire equatorial plane 1A.
The tire of Example 2 is a tire in which the end position in the tire width direction (belt end (cut end) position) of the belt with a cut end is provided at a position of 95% to 100% of the distance A from the tire equatorial plane 1A. .

  As can be seen from the performance test results shown in FIG. 6, the end position in the tire width direction of the belt with a cut end is provided at a position 90% or more away from the tire equator plane 1A in the distance A; In the tire, Comparative Example 1 in which the end position in the tire width direction of the belt with a cut end is provided at a position that is not separated from the tire equatorial plane 1A by 90% or more of the distance A; A good result was obtained that the (travel distance until tire failure) became longer and the member end strain (distortion at the end in the tire width direction of the belt with a cut end) was small.

  In the embodiment, the inner belt portion is constituted by a belt without a cut end and the outer belt portion is constituted by a belt with a cut end. However, the inner belt portion is constituted by a belt with a cut end, and the outer belt portion is not provided with a cut end. You may comprise with a belt.

  The cut endless belt may be a spiral belt. For example, an elongated continuous plate 42 in which a cord 43 formed of organic fiber is covered with rubber is spirally wound from one side of the tire assembly drum (core) 46 to the other side without gaps. You may comprise by the made belt.

1 tire, 1A tire equatorial plane, 4 inner belt part (belt without cut end),
5 Outer belt part (belt with cut end), 43; 53 cord,
51e Tire width direction end position (cut end) of belt (belt with cut end),
51f; 51g End position (cut end) in the tire width direction of a belt (belt with another cut end).

Claims (4)

A belt without a cut end where the cut end of the organic fiber cord is not exposed at the side end of the belt which is located at both ends of the tire in the width direction and continues in the circumferential direction of the tire, and located at both ends of the tire in the width direction. In a tire provided with a belt portion in which a belt having a cut end in which cut ends of organic fiber cords are exposed at both ends of a belt continuous in the circumferential direction of the tire,
When the distance from the tire equator to the tire ground contact position in the width direction of the tire at normal internal pressure and load is distance A, the center position in the tire width direction of the belt with the cut end and the tire equator are matched. The end position in the tire width direction of the belt with the cut end that is installed is provided at a position that is 90% or more of the distance A away from the equator plane of the tire ,
Further, a belt having another cut end is provided on the outer side in the radial direction of the tire than the belt having a cut end provided at a position 90% or more of the distance A from the equator plane of the tire. The tire in the tire width direction is provided at a position closer to the equator plane of the tire than a position 40% of the distance A from the equator plane of the tire. The crossing angle between the organic fiber cord of the belt without end of cut and the equatorial plane of the tire is greater than 0 ° and not more than 30 °;
The tire according to claim 1, wherein an intersection angle between the organic fiber cord of the belt with a cut end and the equator plane of the tire is greater than 0 ° and 25 ° or less.   The tire according to claim 1 or 2, wherein when the diameter of the organic fiber cord of the belt with a cut end is φ, the cord interval of the cut end of the belt with a cut end is larger than 0.4φ. The tire according to any one of claims 1 to 3 , wherein the belt with a cut end is provided on a radially outer side of the tire than the belt without a cut end.

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