JPH0232483Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a retreaded tire that prevents peeling of the joint surface between the base tire and the tread rubber.

In general, retreaded tires using pre-cured retreads are made by bonding pre-vulcanized tread rubber a to the crown portion of a base tire c via an unvulcanized cushion rubber layer b, as shown in Figure 1. However, both the tread rubber a and the base tire c are vulcanized, and therefore it is generally difficult to maintain sufficient adhesion between them. Particularly when this type of retreaded tire is run, the tread rubber a is repeatedly deformed, and both lower ends a1 of the tread rubber a are
The area where the cushioning rubber b is connected to the base tire c is particularly subjected to stress concentration, that is, the cushion rubber b at both ends b1.
causes thermal deterioration, the adhesive strength decreases, and peeling grows in the tire circumferential direction at both lower ends a1 of the tread rubber a.

Conventionally, in order to solve this problem, the composition design and vulcanization conditions of the cushion rubber b were studied, or recesses were formed on the side surfaces of the tread rubber a in order to alleviate the stress concentration at both lower ends a1 of the tread rubber a. Although these methods are effective to some extent under relatively low-load running conditions, none of them can withstand use under high-load and frequent turning conditions. It has not been done.

The purpose of this invention is to provide a retreaded tire that can prevent the tread rubber from peeling off under more severe usage conditions, such as high loads and high turning frequency. A retreaded tire that is bonded and integrated is characterized in that wing portions are provided at both lower end portions of the tread rubber and extend in a direction toward the shoulder portion with a gradually decreasing thickness.

One embodiment will be described below based on the drawings.

In FIG. 2, the retreaded tire 1 of the present invention has a tread rubber 2 bonded and integrated with a base tire 4 via a cushion rubber layer 3. The base tire 4 is
By notching both ends in the axial direction of the tire of the tread surface formed by cutting or buffing the worn surface to an appropriate size, a sloped surface extending diagonally inward toward the shoulder portion is formed. As shown in Fig. 2, the tread surface forms a substantially straight line in the cross section that includes the tire axis, so existing rubber remains at both ends, and by cutting out this remaining rubber, The slope portion is formed. Further, the tread rubber 2 is formed into a substantially triangular shape by gradually decreasing the thickness along the sloped portion at both ends 2a in the tire axial direction of the base portion having a substantially straight bottom surface along the tread surface of the base tire 4. A wing portion 5 having a tapered shape is provided. Thereby, when the tread rubber 2 is attached to the base tire 4, the wing portion 5 can cover the slope portion.

Therefore, in the retreaded tire 1 of the present invention, when stress is transmitted from the tread rubber 2 in contact with the ground to the base tire 4 through the cushion rubber layer 3 during tire running, the tread rubber 2 is bonded to the cushion rubber layer 3 at both lower ends 2a. Due to the tapered region, stress is dispersed from the tread rubber 2 toward the shoulder portion of the base tire 4, and the deformation strain near both ends 2a of the cushion rubber 2 can be significantly reduced.The cushion rubber layer forms a structural fault. Suppressing the local deformation strain that tends to occur near the boundary with 3,
Deterioration of adhesive strength due to thermal deterioration can be prevented. Moreover,
For example, in the conventional retreaded tire shown in Fig. 1, the cushion rubber layer 3 is bonded and integrated by heating and vulcanizing, but since both ends b1 are in closest contact with the heat source, under normal vulcanization conditions. It is about 5 times over-vulcanized than the inside, and the adhesive strength is significantly lower than that of the properly vulcanized inside. On the other hand, in the retreaded tire 1 of the present invention, both ends 2a of the tread rubber 2
Since the nearby portion 3b of the cushion rubber 3 is covered with the wing portion 5, overvulcanization can be prevented. Moreover, the portion 3b of the cushion rubber layer 3 has large deformation strain.
This enables optimal vulcanization and maintains sufficient adhesion, and in conjunction with the fact that the outer edge 3a of the cushion rubber layer 3 is located near the shoulder portion of the base tire 4, the cushion rubber layer It is possible to efficiently prevent the peeling of the tread rubber a, which occurs when the deformation strain is particularly severe in the vicinity of both ends b1 of b.

In this way, the retreaded tire of the present invention has wings at both lower ends of the tread rubber, which effectively disperses the stress transmitted from the ground contact surface and prevents deterioration at both ends of the cushion rubber. Since both ends of the low-profile cushion rubber are moved toward the shoulder portion, local deformation strain in this portion can be alleviated. Furthermore, in this type of tire,
When a tread with a flat inner circumference is attached in a substantially straight cylinder shape to a cylindrical base tire with a flat outer circumference, the boundary surface, that is, the line of the cushion rubber layer, is relatively noticeable.
In the present invention, sloped parts are provided at both ends of the base tire, and the thickness of the wing part is reduced along the sloped parts, so that the line of the cushion rubber layer is formed at the thinner inner end part of the wing part. It is clear that appearance can also be improved by appearance and smudging.

[Brief explanation of the drawing]

Figure 1 is a partial cross-sectional view of a conventional retreaded tire;
The figure is a partial sectional view of the retreaded tire of the present invention. 2... Tread rubber, 3... Cushion rubber layer, 4... Base tire, 5... Wing section.

Claims (1)

[Scope of utility model registration request] In a retreaded tire in which pre-vulcanized tread rubber is bonded and integrated with the tread surface of a base tire through a cushion rubber layer, the base tire remains at both ends of the tread surface which is substantially straight in a cross section including the tire axis. The tread rubber is cut out to provide a sloped portion diagonally inward toward the shoulder portion, and the bottom surface of the tread rubber is approximately linear, and the tread rubber is provided with a bottom surface that is approximately linear and has a thickness along the sloped portion on both sides of the base along the tread surface. A retreaded tire characterized by having a wing portion that gradually decreases in length.