JPH06262704A - Precure tread for recycling and recycled pneumatic tire - Google Patents

Abstract

PURPOSE:To make possible bonding between blocks without reducing the productivity by arranging a long, large block in a row of blocks installed on a precure tread belt corresponding to the circumferential length of a base tire. CONSTITUTION:In a precure tread, more than one main channel 1 extending in the longitudinal direction and a lot of subchannels 2 crossing the main channels are installed on one side of a vulcanized rubber belt 10, and a row of blocks A-E, in which a lot of blocks 3 divided in the main channels 1 and the subchannels 2 are arranged, is formed. In the row of blocks A-E, a long, large block 30 is placed on each position corresponding to the circumferential length of a base tire in the longitudinal direction, and the blocks 30 are arranged sideways on the vulcanized rubber belt 10. In this arrangement, the length PA-PE of the block 30 is longer than any one of the regular blocks 3 arranged in the row of blocks A-E.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a retread pre-cure tread having a block pattern and a pneumatic retread tire using the same.

[0002]

2. Description of the Related Art Generally, in heavy duty pneumatic tires for trucks, buses, etc., when the remaining groove of the tread is reduced and the tire reaches the end of its life, the tread surface is cut and buffed, and the remaining tire body is used as a base. As a tire, it will be reused as a retreaded tire by attaching a new tread again.

As a tread used for such a retreaded tire, a precure tread in which an arbitrary pattern is provided on the surface of a belt-shaped vulcanized rubber plate is used. When producing a retreaded tire, this belt-shaped precure tread is cut into a certain length according to the circumference of the base tire, and it is wound around the outer periphery of the base tire so that both ends are joined and integrated. There is.

However, when the pattern on the surface of the precure tread is a block pattern, since it has a sub-groove that traverses the longitudinal direction, when this precure tread is cut into a certain length according to the outer peripheral length of the base tire, The cutting position may coincide with the position of the sub groove. Therefore, when the cut end surfaces are joined to each other on the base tire, the sub-grooves are joined to each other or the sub-grooves and the blocks are joined to each other.

FIG. 3 and FIG. 4 each show a plane in which pre-cure treads provided with a conventional block pattern are wound around a base tire, and cut end faces are joined at a joint S. The pre-cure tread is provided with a main groove 1 in the longitudinal direction and a sub groove 2 in the width direction, and block rows A to E in which a large number of blocks 3 are arranged are formed. And in each block row, FIG.
The blocks 3 are not always joined as shown in FIG.
As shown in FIG. 5B, the sub-grooves 2 are joined together,
As shown in (C), the block 3 and the sub groove 2 may be joined. However, if the joining at the joining portion S is between the sub-grooves 2 as shown in FIG. 5B or between the block 3 and the sub-groove 2 as shown in FIG. Since the joining area is smaller than that in the case of joining, there is a problem that peeling is likely to occur and durability is reduced.

In order to solve such a problem, when cutting the pre-cure tread according to the outer peripheral length of the base tire, it is necessary to carefully cut it while searching for a position where all blocks are bisected at the same time. However, the position where the blocks of the entire block row are bisected at the same time is only a very limited region as shown by hatching in FIG. 6, so that the cutting work is extremely troublesome and the productivity is significantly reduced. It is inevitable.

[0007]

An object of the present invention is to produce a retreaded tire having a block pattern, from a precure tread and a precure tread capable of always joining blocks without lowering productivity. To provide a manufactured pneumatic retreaded tire.

[0008]

The pre-cured tread for rehabilitation of the present invention which achieves such an object is a pre-cured tread in which a plurality of block rows are provided along the longitudinal direction on the surface of a belt-shaped vulcanized rubber plate. It is a cure tread, and at the position corresponding to the circumference of the base tire, long blocks having a block length larger than the largest block among the blocks regularly arranged in each of the plurality of block columns are arranged side by side. It is characterized by having done.

Further, in the pneumatic retreaded tire of the present invention, a plurality of block rows are provided on the surface of a belt-shaped vulcanized rubber plate along the longitudinal direction thereof, and each block row is regularly arranged in each block row. The precure tread in which large blocks having a block length larger than the maximum block are provided side by side, are cut at an intermediate position of the large blocks corresponding to the circumferential length of the base tire, and are wrapped around the outer periphery of the base tire to form the whole block. It is characterized in that the cut end faces of the block rows are butt-joined to each other.

Since the large blocks are arranged in the block row provided on the belt-shaped pre-cure tread in accordance with the circumferential length of the base tire, the operator takes great care by placing the large blocks at the cutting position. It is possible to cut at the position of the block without paying attention, and it becomes possible to join the blocks to each other in all of the plurality of block rows. As a result, it is possible to efficiently produce a retreaded tire with a low rate of peeling at the joint.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a plan view showing an example of the precure tread of the present invention. In FIG. 1, the precure tread is provided with a plurality of main grooves 1 extending in the longitudinal direction and a large number of sub-grooves 2 crossing these on one side of a belt-shaped vulcanized rubber plate 10. A plurality of block rows A, B, C, D, E in which a large number of blocks 3 divided into 2 are arranged are formed.

Each of the block rows A, B, C, D and E is provided with a large block 30 at each position in the longitudinal direction corresponding to the tire circumferential length of the base tire. The rubber vulcanizates 10 are arranged side by side. The block length P _A, P _{B, of} each long block 30
P _C, P _{D, and} P _E are block blocks A, B, C, and
It is larger than any of the regular blocks 3 arranged in D and E. Preferably, the block length P _A, P _B, P _C, P _D, P _E of the long block 30 is 2 which is the maximum block length of the regular blocks in each block string.
It is desirable to set the range to 3 times.

When a retreaded tire is produced using the above-mentioned pre-cure tread, it is cut into a certain length according to the outer peripheral length of the base tire, and is attached so as to be wound around the outer periphery thereof, and the cut end faces are joined together. Must be joined. However, in the above-mentioned precure tread, since the large block rows 30 are arranged side by side in each of the block rows A to E at each position corresponding to the outer peripheral length of the base tire, the long blocks of all the block rows A to E are arranged. A longitudinal allowance region L that allows the 30 to be bisected simultaneously can be ensured as shown.

Therefore, when the operator cuts the precure tread according to the outer peripheral length of the base tire, the operator can easily secure the adjustment allowance to match the outer peripheral length of the base tire and easily perform the operation on all the block rows A to E. The large block 30 can be bisected at the same time. The pre-cure tread thus cut is wound around the base tire, and the cut end surfaces are joined at the joining portion S to manufacture a retreaded tire in which the large blocks 30 are newly joined for each block row A to E. be able to. Therefore, it is possible to obtain a retreaded tire having a high bonding strength and a low peeling occurrence rate.

[0015]

EXAMPLE A precure tread of the present invention shown in FIG.
Using each of the conventional pre-cure treads shown in FIG. 6, 50 retread tires having a tire size of 1000R20 14PR were manufactured. For these retreaded tires according to the present invention and conventional retreaded tires, the rate at which the joining of blocks in the joining portion is obtained in all block rows, and the peeling occurrence rate by the following method were evaluated,
The results shown in Table 1 were obtained.

Peeling rate evaluation method : In the defective tires recovered from the general market, the number of tires in which the joint portion of the precure tread is peeled is divided by the number of retreaded tires produced in the same period and peeled. The occurrence rate was calculated and the values of the tire of the present invention and the comparative tire were compared. The value was represented by an index with the peeling occurrence rate of the conventional retreaded tire as 100.
The smaller the index value, the smaller the peeling occurrence rate.

[0017] From Table 1, in the present invention, all the retreaded tires have a structure in which blocks are joined together at their joints, whereas the conventional retreaded tire is only 13%. Therefore, it can be seen that the retreaded tire of the present invention has a significantly reduced peeling occurrence rate.

[0018]

EFFECTS OF THE INVENTION According to the present invention, since the large blocks are arranged in correspondence with the circumference of the base tire in the block row provided on the belt-shaped pre-cure tread, cutting is performed at the position of the large blocks. By doing so, it is possible to always join the blocks in each block row without deteriorating the workability. Therefore, it is possible to easily manufacture a retreaded tire having a high peel resistance of the tread.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a precure tread of the present invention.

FIG. 2 is a plan view showing a joint portion of a tread of a retreaded tire using the precure tread of FIG.

FIG. 3 is a plan view showing a joint portion of a tread of a conventional retreaded tire.

FIG. 4 is a plan view showing another example of the joining portion of the tread of the conventional retreaded tire.

5A is a sectional view taken along line XX of FIG. 3 and FIG. 4, FIG. 5B is a sectional view taken along line YY of FIG. 3, and FIG.
It is a Z sectional view.

FIG. 6 is a plan view of a conventional precure tread.

[Explanation of symbols]

1 Main Groove 2 Sub Groove 3 Block 30 Long Block A, B, C, D, E Block Row S Joint

Claims (2)

[Claims] 1. A precure tread in which a plurality of block rows are provided on a surface of a belt-shaped vulcanized rubber plate along a longitudinal direction thereof, and the plurality of blocks are provided at a position corresponding to a circumferential length of a base tire. Pre-cure tread for rehabilitation in which large blocks having a block length larger than the largest block among blocks regularly arranged in each block column are arranged side by side for each column. 2. A block-shaped vulcanized rubber plate is provided with a plurality of block rows along the longitudinal direction on the surface thereof, and each block row has a block length larger than the largest block among the blocks regularly arranged. The precure tread with the blocks arranged side by side is cut at the intermediate position of the large block corresponding to the circumference of the base tire, and is wound around the outer circumference of the base tire to abut the block cut end faces in the entire block row. Bonded pneumatic retread tire.