JPH0321508A - Radial tire for aircraft - Google Patents

Abstract

PURPOSE:To prevent generation of separation, etc., around a terminal part by constituting a tire in the caption so that a terminal of a carcass up ply is not arranged in an area in the contact with a rim flange accompanying deformation from a no-load state to a 200% load state of a tire. CONSTITUTION:It is so constituted that a terminal 26A of a carcass up ply 26 is not arranged in a specific area which is brought into contact with a rim flange 32 accompanying deformation from a no-load state to a 200% load state of a tire 20. That is, the terminal 26A of the carcass up ply 26 is arranged on both sides of an area 38 surrounded by a first perpendicular (m) passing a separating point 34 of a tire outer surface and the rim flange 32 and crossing the middle part of the carcass up ply 26 in an internal pressure filled state and a no-load state, and a second perpendicular (n) passing the separating point 34 in an internal pressure filled state and a 200% load state and crossing the middle part of the carcass up ply 26 in an internal pressure filled state and a no-load state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radial tire for aircraft such as jet passenger aircraft.

[Conventional technology]

In aircraft radial tires used at high internal pressures, a so-called atpu-down carcass structure is adopted because it can advantageously prevent braking pullout burst from the Kerr force sply end separation.

This is because when used at high internal pressure for a long period of time, the internal pressure filled in the tire at the up-ply unwinding section creates a force that tries to pull the tire out, in other words, excessive shearing force generated between the carcass and the bead core is applied to the carcass. This is because it can be reduced by plying, and the occurrence of separation at the turned-up portion can be advantageously suppressed.

The up-down carcass structure is a carcass up-ply tire radius in which a plurality of terminal parts are provided in layers in the tire radial direction along the inner surface of the tire, and the terminal parts go around the bead core from the inside in the tire width direction and are rolled up to the outside in the tire radial direction. A structure is known in which a Kerr force down briar whose end portion goes around the bead core from the outside in the width direction of the tire along the inner surface of the tire is arranged.

In addition, when using multiple carcass up ply and carcass down ply, the terminal parts overlap and stress is concentrated.
It is known to arrange the terminals of these carcass braises with steps to prevent them from forming a core of separation.

However, in such an up-ply carcass structure, depending on the arrangement of the terminals of the carcass up-ply,
This causes inconveniences such as separation.

That is, since radial tires for aircraft are used under high loads and large deflections, the bead portion undergoes large collapse deformation during load transfer, and is subjected to large contact pressure at the contact portion with the rim flange.

For this reason, if the end of the carcass up ply is located in the area that contacts the rim flange, stress will be concentrated in this area and separation will occur. Also, Unexamined Japanese Patent Publication No. 6
As disclosed in No. 4-4 7 6 0 5, if each end of a plurality of carcass up plies is placed above the bead core along the middle part of the carcass up ply, it will come into contact with the rim flange during load transfer and be greatly deformed. In the area where the carcass up ply is rolled up, the wound portions of each carcass up ply are arranged in a layered manner, making the entire carcass layer thicker. This increases the compressive strain that occurs in the carcass down ply located closer to the outer surface of the tire, reducing the durability of the carcass down ply. .

[Problem to be solved by the invention]

The present invention takes the above-mentioned facts into consideration, and aims to eliminate the disadvantages such as separation occurring around the terminal part of the carcass up ply and a decrease in the durability of the carcass down ply in the atpu down carcass structure. The purpose is to obtain a radial tire for aircraft that is capable of

[Means to solve the problem]

The present invention provides a plurality of layers in the tire radial direction along the inner surface of the tire, each end portion of which is wound around a bead core along the inner surface of the tire from the inside in the tire width direction and rolled up to the outside in the tire radial direction. A carcass up ply in which at least one end part is rolled up along the middle part along the inner surface of the tire and radially outward of the tire, and a carcass up ply which is provided along the inner surface of the tire radially outside of the carcass up ply and whose end part is a bead core. A radial tire for aircraft having a carcass down ply that goes around from the outside in the width direction of the tire, and a carcass down ply that goes around the carcass up ply through the point of separation between the outer surface of the tire and the rim flange when the internal pressure is filled and no load is applied. The middle part of the carcass up ply passes through the first perpendicular line perpendicular to the part and the point of separation between the outer surface of the tire and the rim flange when the internal pressure is filled and the load is 200% of the standard load, and the middle part of the carcass up ply when the internal pressure is filled and the load is 200% of the standard load. The present invention is characterized in that the terminals of each Kerr force sup-up braai are distributed and arranged on both sides of the area surrounded by the second perpendicular line which intersects at right angles.

Further, the carcass up-ply terminal located on the outside in the tire radial direction with respect to the area surrounded by the first perpendicular line and the second perpendicular line as a boundary is moved from the inner circumferential end of the tire to the rim flange height 1.
The tire is characterized by being located at a distance of more than seven times the distance in the tire radial direction.

Further, the present invention is characterized in that another carcass up-ply terminal is disposed at a position shifted in the tire radial direction from the point where one end of the carcass up-ply starts along the middle part of the carcass up-ply. In addition, in the above, "standard load" means The Tire
and Rim Association Stand
shall mean the maximum load of the ards standard.

[Effect]

In the present invention having the above structure, the end of the carcass up ply is arranged within a region surrounded by a perpendicular line to the middle part of the carcass up ply passing through both ends of the part that contacts the rim flange during deformation from a no-load state to a 200% load state. It has not been. Therefore, if the load is within 200%, there will be no inconvenience that stress will be concentrated at the end portion of the carcass assembly and separation will occur. Here, the 200% load state is used as one side of a double wheel,
If the other tire becomes punctured, a load of 200% will be applied, and this is to prevent severance from occurring even in this case.

In addition, the carcass up ply terminals are concentrated on the outside in the tire radial direction with the area as a boundary, and the entire carcass layer is prevented from becoming thick in the area, which increases the compressive strain that occurs in the car force down ply during load transfer. This prevents a decrease in the durability of the carcass down ply. Note that even if the end of each carcass up ply is placed on the inside in the tire radial direction with the area as a boundary, it is possible to avoid thickening of the entire carcass layer in the area, but in this case, the length of the carcass at the turned-up part Due to the short length, the pull-out force increases due to the internal pressure of the carcass end, and the disadvantage is that it is no longer possible to advantageously prevent blithe pull-out burst from the Kerr force sply end separation.

In addition, by locating the carcass up-ply terminal located on the outside in the tire radial direction with the above-mentioned area as the boundary, at a position more than 1.7 times the rim flange height from the inner peripheral edge of the tire, the occurrence of separation is more reliably achieved. can be prevented. In other words, deformation is large near the point of separation between the tire outer surface and the rim flange during load transfer, so in order to further prevent stress from concentrating around the carcass up-ply terminal, the carcass up-ply terminal should be moved closer to the inner circumference of the tire. It is desirable to arrange it at a position at least 1.7 times the rim flange height from the end.

Separation can also be prevented by locating the end of the other carcass upply at a position shifted in the tire radial direction from the point where the unwound part of one of the carcass upply starts along the middle part of the carcass upply. It can be prevented. In other words, at the part where at least one unwinding part of each carcass upply begins to follow the middle part of the carcass upply, strain is concentrated due to the movement of each bly during load transfer, and the other carcass upplies are strained at this part. If you place a terminal in

〔Example〕

1 and 2 show a cross-sectional shape of an aircraft radial tire 20 to which the present invention is applied (hatching of the rubber portion is omitted from the illustration).

In the radial tire 20, as shown in FIG. 2, a belt 24 is provided on the inside of the tread 22 in the tire radial direction. A plurality of belts 24 are provided, and these are arranged in layers in the tire radial direction.

A carcass up ply 26 and a carcass down ply 28 are provided inside these belts 24 in the tire radial direction along the inner surface of the tire.

A plurality of carcass up plies 26 are provided, and these are arranged in layers in the tire radial direction along the inner surface of the tire. The end portion of each carcass up ply 26 is wound around the bead core 30 from the inside in the tire width direction along the inner surface of the tire and rolled up to the outside in the tire radial direction, and each end is arranged with steps. That is, each carcass up ply 26 has a different length, and each carcass up ply 26 goes around the bead core 30 from the inside in the tire width direction in order of shortest length, and as it moves away from the bead core 30 to the outside in the radial direction, the end of the carcass up ply 26 is different. is spaced outward from the bead core 30 in the tire radial direction. and,
A turned-up portion 26A of the carcass up ply 26 that is farthest from the bead core 30 in the radial direction extends along an intermediate portion along the inner surface of the tire.

A plurality of carcass down plies 28 are provided, and these are arranged in a layer on the outside of the carcass up ply 26 in the tire radial direction. The terminal part of each carcass down ply 28 goes around the bead core 3.0 along the inner surface of the tire from the outside in the tire width direction, and each terminal part is attached to the bead core 3.0.
It is placed with a step closer to the inner edge of the tire. That is, each carcass down ply 28 has a different length, and each carcass down ply 2 is arranged in descending order of length.
8 goes around the bead core 30 from the outside in the tire width direction, and the longer it goes away from the bead core 30 in the radial direction, the shorter it goes around the bead core 30.

In the radial tire 20 constructed in this way, the rim flange 3 is deformed from a no-load state to a 200% loaded state.
The placement of the ends of the carcass up-ply 26 in the area of contact with the carcass up-ply 26 is avoided.

To explain in detail, the internal pressure filled state and no load state (first
The first perpendicular line m passes through the separation point 34 between the outer surface of the tire and the rim flange 32 and is orthogonal to the middle part of the carcass assembly in the state shown by the solid line in the figure.
A second perpendicular line passes through the separation point 36 between the outer surface of the tire and the rim flange 32 in the loaded state (the state shown by the two-dot chain line in FIG. 1) and is orthogonal to the middle part of the carcass up-ply in the internal pressure filled state and no-load state. A height L that is outside in the tire radial direction with respect to the region 38 surrounded by n and that is further away from the tire inner circumferential end than 1.7 times the height H of the rim flange 32. The terminal of the carcass up-ply winding portion 26A is arranged at a position outside of the carcass up-ply winding portion 26A. The terminals of each of the other carcass up plies 26 are located on the inner side of the region 38 in the tire radial direction, and are shifted in the tire radial direction from the starting point 40 where the carcass up ply winding portion 26A starts along the middle part of the carcass up ply. It becomes.

According to the above-mentioned precautions, it is possible to avoid placing the car force branch end in the area 38 that contacts the rim flange 32 during deformation from a no-load state to a 200% load state, and if the load is within 200%, the carcass There is no problem that stress is concentrated at the end of the braai and separation occurs.

In particular, the end of the turned-up portion 26A of the carcass up ply 26 located on the outside in the tire radial direction with the region 38 as a boundary is set at 1.7 of the height H of the rim flange 32 from the inner peripheral end of the tire.
Since it is placed at a position farther outward in the tire radial direction than twice the distance, the outer surface of the tire and the rim flange 32 are separated during load transfer.
Even if there is a large deformation in the vicinity of the carcass up-ply, this deformation causes less stress concentration on the end of the rolled-up portion 26A of the carcass up-ply, which is effective in preventing separation. In addition, the terminals of each car force sub-ply 26 located on the inner side in the tire radial direction with the area 38 as the boundary are arranged to be shifted in the tire radial direction from the starting point 40 where the rewinding portion 26A of the carcass up ply starts along the middle part of the carcass up ply. Therefore, it is not significantly affected by distortion caused by the movement of each ply during load transfer, and this is also effective in preventing the occurrence of separation.

Further, it is possible to prevent the ends of each carcass up ply 26 from concentrating on the outside in the tire radial direction with the region 38 as a boundary, and to prevent the entire carcass layer from becoming thicker within the region 38, thereby reducing the compressive strain that occurs in the carcass down ply 28 during load transfer. There is no problem that the durability of the carcass down ply 28 is reduced.

Note that it is also possible to avoid thickening of the entire carcass layer within the area 38 by arranging the ends of the carcass upblyers 26 on the inside in the tire radial direction with the area 38 as the boundary; The disadvantage is that ply pullout bursts from the cusp-ply end separations cannot be advantageously prevented.

(Experimental Example) The radial tire 20 according to this example, the radial tire for aircraft having the structure shown in FIG. 3, and the radial tire for aircraft having the structure shown in FIG. Internal pressure 1 at 5. 6kg/cd, load 55200Lbs, speed 40MPH, distance 35000f
The drum test was conducted 50 times under the condition of t/times, and after the drum test, the drum was dissected to investigate the failure condition. Note that the aircraft radial tire having the structure shown in FIG. 3 has a structure in which the terminal of the Kerr force sup-up brai 50 is also arranged in a portion corresponding to the region 38 of this embodiment.

Further, in the aircraft radial tire having the structure shown in FIG. 4, the terminals of each Kerr force splice 52 are arranged closer to the outside in the tire radial direction than the portion corresponding to the region 38 of this embodiment. .

Table 1 As a result, as shown in Table 2 below, with the aircraft radial tire having the structure shown in FIG. 3, separation occurred in the vicinity of the car carousel upb1 lie end during the drum test, making it impossible to run. On the other hand, although the aircraft radial tire with the structure shown in Figure 4 completed the race,
Cord breakage was observed in part of the carcass down ply. On the other hand, in the aircraft radial tire according to this example, no failure was observed as in the aircraft radial tire having the structure shown in FIGS. 3 and 4.

Table 2 [Effects of the Invention] As explained above, the present invention solves inconveniences such as separation occurring around the terminal portion of the carcass up ply and deterioration of the durability of the carcass down ply. It has excellent effects.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the aircraft radial tire according to the present invention, FIG. 1 is an enlarged sectional view of the main part, FIG. 2 is a sectional view showing the overall structure, and FIGS. 3 and 4. 1A and 1B are sectional views of main parts corresponding to FIG. 1, respectively, showing the structure of a comparative example. 20... Radial tire, 26... Carcass up ply, 28... Carcass down ply, 30... Bead core, 32... Rim flange.

Claims (3)

[Claims] (1) A plurality of layers are provided along the inner surface of the tire in the tire radial direction, and each terminal part goes around the bead core along the inner surface of the tire from the inside in the tire width direction and is rolled up to the outside in the tire radial direction, and at least A carcass up ply in which one end part is wound up along the inner surface of the tire along the middle part along the inner surface of the tire, and a carcass up ply in which one end part is wound up along the inner surface of the tire at a position outside the carcass up ply in the radial direction of the tire and one end part is wound up along the inner surface of the tire. This aircraft radial tire has a carcass down ply that goes around the bead core from the outside in the width direction of the tire, and a carcass up ply that passes through the point of separation between the outer surface of the tire and the rim flange when the internal pressure is filled and there is no load. The first perpendicular line perpendicular to the midpoint of A radial tire for an aircraft, characterized in that terminals of each carcass up-ply are distributed and arranged on both sides of a region surrounded by a second perpendicular line perpendicular to a second perpendicular line. (2) The carcass up-ply terminal located on the outside in the tire radial direction with respect to the area surrounded by the first perpendicular line and the second perpendicular line as a boundary, is moved from the inner circumferential end of the tire to the rim flange height 1.
The radial tire for an aircraft according to claim 1, wherein the radial tire for an aircraft is arranged at positions separated in the tire radial direction by a distance of seven times or more. (3) The other carcass up ply terminal is arranged at a position shifted in the tire radial direction from the point where one of the carcass up plies turns back along the intermediate part of the carcass up ply. (1)
Aircraft radial tires described in .