JPH011603A - low pressure tires - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a low-pressure tire for an all-terrain vehicle that is lightweight while maintaining shock absorption and damping properties.

[Conventional technology]

Generally speaking, all-terrain vehicles (
Tires for so-called ATVs are subject to particularly severe shocks during running, and therefore are required to have good shock absorption and vibration damping properties.

In particular, this type of vehicle often does not have a suspension system, and the tire itself is a suspension mechanism absorber.
It is necessary to have the functions of For this reason, in order to reduce the longitudinal spring constant of the tire by adjusting the rubber thickness of the sub-tread part under the groove of the tire body, the carcass cord angle, and the material of the carcass cord, which have a large influence on the above-mentioned characteristics, for example, Japanese Patent Application Publication No. No. 60-234008 has been proposed. In this proposal, a tire is constructed of a tire body whose rigidity gradually increases from the tire crown toward the tire bead, and tread rubber disposed at the crown of the tire body.

[Problem that the invention seeks to solve]

However, although this tire has the effect of absorbing and mitigating shock, the rubber thickness increases from the crown to the bead of the tire body, which inevitably increases the weight of the tire as a whole.

The present invention solves the above-mentioned problems and aims to provide a low-pressure tire that can absorb and cushion shocks and also reduce the weight of the tire.

[Means for solving problems]

The present invention provides a tire body including a pair of left and right bead cores;
This is a low-pressure tire consisting of tread rubber and sidewalls arranged in the crown portion of the tire body, and the maximum rubber thickness Tx of the tire body between the tread contact edge E and the tire maximum medium HP is the tread. A low pressure tire characterized by being 1.3 to 3.5 times the rubber thickness TE of the tire body at the ground contact edge E and 1 to 2.5 times the rubber thickness TP of the tire body at the tire maximum width position P. It's a tire.

An embodiment of the present invention will be described below with reference to the drawings.

The low-pressure tire T consists of a tire body 1 and a tread rubber 2, and the tire body 1 has a carcass 4 buried therein, the end of which is folded back from the inside to the outside at a bead core 3. The tire body 1 is usually constructed using natural rubber, synthetic rubber, etc., but various elastomers such as polyurethane can also be used.

Furthermore, the maximum rubber thickness T in the vicinity of the shoulder portion T
x is a value in the range of 4 to 9 fl, and tread contact @
Subtrend rubber thickness TE at E 1.3 to 3.5
If it is smaller than 1.3 times, the impact absorption and relaxation effect will not be sufficient (the so-called damping effect will be poor, the momentum will continue easily, and the running performance on rough roads will be significantly inferior.3. If it exceeds 5 times, the tire weight will increase, and the damping performance will be good, but the shock absorption performance will be poor.Furthermore, for the same reason, the rubber thickness Tx is set to 1. It is set at 1 to 2.5 times.

As a result, the rubber thickness TE of the tire body 1 gradually decreases toward C (rubber thickness TL) and tire maximum width position P (rubber thickness TP). Furthermore, from the maximum medium HP, tire T
The thickness increases toward the upper end R where it contacts the rim 7, increasing the lateral rigidity. The rubber thickness TE of the tire body at the tread contact edge is defined as the rubber thickness from the groove bottom 5a of the tread groove 5 to the inner surface of the tire and to the carcass in a direction perpendicular to the inner surface. Here, the trend ground contact edge E is determined with the specified internal pressure filled and installed in the vehicle.

In addition to the bead core 3 and carcass 4, the tire body 1 can also be provided with a bead reinforcing layer and a bead apex, and can also be configured as a so-called cordless tire that does not include these reinforcing materials.

Furthermore, in order to manufacture the tire T, it is possible to form the tire body 1 in advance and then arrange the tread rubber, or in the case of a cordless tire, injection molding may be used to construct the tire body and the tread rubber as one body at the same time. It is possible.

In addition, it is possible to increase the lateral rigidity and maintain steering stability by providing a fiber cord layer extending from the bead toward the sidewall, or by increasing the rubber thickness from the tire maximum width position P toward the bead. preferable.

〔Example〕

ATV tie tires with various specifications shown in Table 1 were made using cross-ply tires (two nylon carcass) having a tire size of 22×11.00-8 and the structure shown in FIG. 1.

FIG. 2 shows the rubber thickness distribution of the tire body of these trial tires. In Comparative Example 1, the thickness gradually increases from the tire equator to the bead part, in Comparative Example 2, the thickness increases from the tire equator to the bead part, and in Example 1, the thickness increases from the tire equator to the tire bead part. The thickness gradually decreases toward the tire maximum width position. AT these prototype tires
Table 1 shows the damping feeling effect when installed on V and driven in an actual vehicle.

〔Effect of the invention〕

In this way, in the present invention, the rubber thickness is made thickest at the tire shoulder part, and the rubber thickness is made thinner at the tire crown part and sidewall part, so that a relatively small impact during driving becomes flexible, and the round part and longitudinal spring are made thinner. It is effectively absorbed and relaxed in the sidewall portion with a small constant. Furthermore, since the rubber thickness of the shoulder portion is large, deformation of the headrest during driving is suppressed. Moreover, the energy due to deformation is converted into thermal energy by the rubber thickness of the TX portion, and it functions effectively as a good shock absorber. In addition, the effect of the rubber thickness in the TX section has an effect on vibration damping properties even for motocross competition tires used at relatively low pressures, and can effectively prevent the springy response that occurs in conventional tires due to the rubber bulge, resulting in a damping effect. This increases ride comfort and driving safety. Furthermore, since the rubber thickness of the crown portion and sidewall portion is small, it is possible to reduce the weight.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the right half of the tire of the present invention, and FIG. 2 is a graph showing the distribution of wall thickness at each part of the tire body. ■- Tire body, 2- Tread rubber, 3- Bead core, 4- Carcass, 5- Trend groove.

Claims (2)

[Claims] (1) A low-pressure tire consisting of a tire body including a pair of left and right bead cores, tread rubber and sidewalls arranged at the crown part of the tire body, the tread contact edge E and the tire maximum width position P. The maximum rubber thickness Tx of the tire body between 1.3 to 3.5 times the subtread rubber thickness TE of the tire body at the tread contact edge E and the rubber thickness TP at the tire maximum width position P of the tire body 1.
A low-pressure tire characterized by having a pressure of 1 to 2.5 times. (2) The low pressure according to claim 1, wherein the rubber thickness of the tire body is maximum near the shoulder portion and gradually decreases toward the tire equator C and the tire maximum width position P. tires.