JPH0596654A - Precured tread for reclaimed tire, its manufacture and reclaimed tire for which it is used - Google Patents

Abstract

PURPOSE:To constitute the title method so that the maximum wet capacity can be displayed from the middle period to the last period of wear and tear, by a method wherein at the time of vulcanization molding of a precured tread for a reclaimed tire within a mold, a main groove is formed at the same time and a back sipe whose bottom of groove is positioned closer to the tread side than the bottom of the main groove is formed on a base tire side after vulcanization. CONSTITUTION:Four zigzag main grooves 16 of a circumferential direction are formed in a tread 14A of a precured tread 14 for reclamination at the time of vulcanization molding within a mold. Then back sipes 18 are arranged at equal intervals on a back side (base tire 12 side) of the precured tread 14 in a circumferential direction (direction of arrow A). Pitch P2 of the back sipes 18 is set at about 5-50mm and a longitudinal direction is inclined by about 0 deg.-60 deg. in a widthwise direction of the tire. Then the bottom of a groove of the back sipe 18 is established at the depth of the groove of about 40-80% of the depth D1 of the groove of the main groove 16 so that the bottom of the groove of the back sipe 18 is positioned closer to the tread part 14A side than the bottom of a groove of the main groove 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precured tread for retreaded tires, a method for producing the same, and a retreaded tire using the precured tread. The present invention relates to a manufacturing method and a retreaded tire using the method.

[0002]

2. Description of the Related Art Conventionally, tread treads of retreaded tires are
Main grooves and sipes are formed to improve wet performance. From the initial wear of the tread to the middle wear, the wet performance is improved by this main groove and sipes, but from the middle wear to the end wear, the groove depth of the main groove decreases and the sipes disappear, so the wet performance is improved. The decline was unavoidable.

As a method of solving the above-mentioned drawbacks, a backside sipe is provided on the backside of a pre-cure tread used for a retreaded tire, and the backside sipe is exposed as the tread wears and the deterioration of wet performance is prevented. A tire has been proposed (JP-A-3-153406).

The mold for vulcanizing and molding the precure tread used for this retreaded tire is provided with a plurality of blades for forming backside sipes on the side forming the back surface of the precure tread, and the blades are provided. Bones (projections) for forming the tread pattern are provided on the surface facing the surface, that is, the side forming the tire tread side.

[0005]

However, the blade for forming the backside sipe provided in the mold must be arranged so as not to come into contact with the bone for forming the tread pattern, and the degree of freedom of arrangement is small. Also, it is difficult to form many backside sipes. For example, when forming a backside sipe that extends in the axial direction in a rib pattern having a circumferential main groove, only the so-called blind sipe in which the tip of the backside sipe is located inside the rib can be formed, and wet performance at a high level. Could not be maintained.

Further, the blade forming the backside sipe must be formed thin, and if the durability of the mold is emphasized, the width of the backside sipe becomes wider, which adversely affects the rigidity of the tread and lowers the wear resistance. There are conflicting problems.

In consideration of the above facts, the present invention is for a retreaded tire having a backside sipe capable of exhibiting maximum wet performance from the middle wear period to the last wear period without being affected by the tread pattern on the tread side. It is an object to provide a precure tread, a method for producing the same, and a retreaded tire using the same.

[0008]

According to the method of manufacturing a precure tread for a retreaded tire according to claim 1, the precure tread for a retreaded tire is disposed on the tire tread side when vulcanizing and molding the precure tread for a retreaded tire. Main groove is formed at the same time, on the base tire side of the vulcanized precured tread for retreaded tire,
It is characterized in that a backside sipe whose groove bottom is located closer to the tire tread portion side than the groove bottom of the main groove is formed by cutting.

The precure tread for retreaded tire according to the second aspect of the invention is characterized by being manufactured by the method according to the first aspect.

Further, the retreaded tire according to claim 3 is characterized in that the precure tread for retreaded tire according to claim 2 and the base tire are adhered to each other via an unvulcanized cushion rubber.

[0011]

According to the method for producing a pre-cure tread for retreaded tire of the present invention, the pre-cure tread is vulcanized in the mold to form the main groove on the tire tread side.
Then, the vulcanized precure tread is formed with a backside sipe whose groove bottom is located closer to the tire tread surface side than the groove bottom of the main groove. Since this backside sipe is performed after vulcanization molding of the precure tread, it can be formed at any position without being affected by the position or size of the main groove. The pre-cure tread on which the backside sipe is formed is disposed on the base tire via an unvulcanized cushion rubber, and then vulcanized and adhered to the base tire.

In the retreaded tire manufactured in this manner, the rear sipe is exposed to the tire tread portion before the precure tread wears and the main groove disappears due to use, and the wet performance deterioration due to the main groove is caused. To prevent the deterioration of wet performance. Moreover, since the size and position of the rear sipe can be freely set without being affected by the main groove, the wet performance of the retreaded tire is maximized. In addition, the backside sipe formed by the notch can have a groove width that is substantially negligible unlike the backside sipe formed by molding, and thus reduces the rigidity of the precure tread grounded on the road surface. And does not reduce wear resistance.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, a vulcanized precure tread 14 is vulcanized and adhered to a crown portion 12A of a base tire 12 used for a retreaded tire 10 via a sheet-shaped cushion rubber 13. .. The precure tread 14 has a thickness T of 16 mm and a width W of 180 in this embodiment.
It is set to mm.

As shown in FIGS. 1 and 2, the tread portion 14A of the precure tread 14 is provided with four main grooves 16 formed in a zigzag shape in the circumferential direction. These main grooves 16 have a substantially U-shaped cross section and have a groove depth D1.
Is set to 13 mm in this embodiment, and the width W of the opening is
1 is set to 10 mm in this embodiment. The pitch P1 in the width direction of the main groove 16 is set to 30 mm in this embodiment. In addition, a plurality of unillustrated sipes are provided on the tread portion 14A side.

On the back side (side of the base tire 12) of the precure tread 14, back side sipes 18 are arranged at equal intervals in the circumferential direction (direction of arrow A in FIGS. 1 and 2). The pitch P2 of the backside sipes 18 in the circumferential direction is preferably 5 to 50 mm, and in this embodiment, the pitch P2 is set to 30 mm. The longitudinal direction of these backside sipes 18 is preferably inclined in the range of 0 ° to 60 ° with respect to the tire width direction,
In this embodiment, the longitudinal direction of the backside sipe 18 is the same as the tire width direction (the direction of arrow B in FIGS. 1 and 2). If the longitudinal direction of the backside sipe 18 exceeds 60 ° with respect to the tire width direction, the rigidity of the ribs decreases.

These backside sipes 18 have a groove depth D1 of 4 in the main groove 16 since the precure tread 14 is new.
It is preferable to set the groove depth D2 so that the groove depth D2 is exposed to the surface of the tread surface portion 14A when worn by about 80%. In the present embodiment, the groove depth D2 of the backside sipe 18 is equal to the main groove depth 6
It is set to 8.2 mm so that it will be exposed when split wear occurs, and the backside sipe 18 is at the intersection of the main groove 16 and the main groove 16
Is exposed in the vicinity of the bottom portion 16A. Also, the backside sipe 18
The width W2 of the tire in the width direction is set to a dimension that is not exposed at both ends of the precure tread 14 in the width direction.

As shown in FIGS. 2 and 3, a short rear sipe 20 is provided on the rear side of the precure tread 14. This short rear sipe 20 is a rear sipe 18
It is arranged between the outermost main groove 16 and the central main groove 16 at an intermediate portion between the rear sipe 18 and the rear sipe 18, and is parallel to the rear sipe 18. Also, this short rear sipe 2
A width W3 of 0 in the tire width direction is set in a range not exposed to the main groove 16, and is set to 20 mm in this embodiment. The depth D3 of the short rear sipe 20 is the same as that of the rear sipe 18, and is set to 8.2 mm.

Next, the manufacturing method and operation of the retreaded tire 10 of this embodiment will be described. This pre-cure tread 14 is molded by a mold for vulcanization (not shown) by a usual method, but only the bone portion forming the main groove 16 is provided on the inner surface of the mold, No blade is provided for forming the sipe 18 and the short rear sipe 20. Therefore, the vulcanized precure tread 14 has a main groove 1
Only 6 are formed.

The vulcanized precure tread 14 contains
Thereafter, a backside sipe 18 and a short backside sipe 20 are formed from the back side of the precure tread 14 by a not-shown blade or the like. Therefore, the rear sipe 18 and the short rear sipe 20 do not have a space portion unlike the sipe formed by providing the mold with a blade, and the groove width is substantially negligible. The short rear sipe 20 may have a space formed by a blade during precure tread vulcanization molding.

The precure tread 14 on which the backside sipes 18 and the short backside sipes 20 are formed is disposed on the base tire 12 from which the tread worn by use has been removed in advance via an unvulcanized cushion rubber 13. Then, it is vulcanized and bonded.

A retreaded tire 10 manufactured in this way
From the early stage to the middle stage of wear of the precure tread 14, the wet performance is exhibited by the effect of the main groove 16.

Wear in which the wear of the pre-cure tread 14 progresses and the groove depth of the main groove 16 becomes shallow and narrow, and the sipes (not shown) provided on the tread side disappear, resulting in a slight decrease in wet performance. In the middle period, the rear sipe 18 and the short rear sipe 20 are exposed to the tread portion 14A, and the main groove 16 is exposed.
The reduction of the groove depth and groove width and the deterioration of the wet performance due to the disappearance of the tread side sipes are compensated. Therefore, the initial wet performance can be maintained from the initial stage of wear to the final stage of wear.

Further, since the groove widths of the rear sipe 18 and the short rear sipe 20 are practically negligible, the rigidity of the precure tread 14 grounded on the road surface does not decrease and the wear resistance does not decrease. ..

A second embodiment of the present invention will be described below with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 4, only the backside sipes 18 are provided on the backside of the precure tread 14 of this embodiment. Further, in this embodiment, the pitch P2 in the circumferential direction of the rear sipe 18 is set to 15 mm. In addition,
Other configurations and operations are similar to those of the first embodiment.

A third embodiment of the present invention will be described below with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 5, only the short back sipe 20 is provided on the back side of the precure tread 14 of this embodiment, and the short back sipe 20 is arranged in a staggered pattern. The rest of the configuration and operation are similar to those of the first embodiment.

Although the short rear sipe 20 is linearly extended in the tire width direction in each of the above-described embodiments, the present invention is not limited to this, and as shown in FIG. It may be bent, and as shown in FIG. 7, the short rear sipe 20 may be arranged so as to be inclined with respect to the tire width direction, and although not shown, other shapes such as a corrugated shape and a zigzag shape may be used. Good. Similarly, the rear sipe 18 may be arranged to be inclined with respect to the tire width direction, and may have another shape such as a corrugated shape.

Further, although the rib type tread pattern is shown in each of the embodiments, the present invention is not limited to this, and the tread pattern of the precure tread 14 is a block pattern, a rug pattern, or a mixed pattern thereof. May be.

Further, in the embodiment, the short rear sipe 20 and the rear sipe 18 have the same groove depth, but the present invention is not limited to this, and the groove depths may be different from each other. In this case, the number of sipes appearing on the tread portion 14A can be increased as the wear of the precure tread 14 progresses, and the wet performance does not deteriorate even at the end of wear.

In the embodiment, the backside sipes 18 and the short backside sipes 20 are arranged at the same pitch in the circumferential direction, but the present invention is not limited to this, and the backside sipes 18 and the short backside sipes 20 are arranged in the circumferential direction. The pitch of may be irregular pitch.

Further, in the embodiment, the groove depths of the rear sipe 18 and the short rear sipe 20 are constant along the width direction, but the present invention is not limited to this, and the rear sipe 18 and the short rear sipe 20 are not limited to this. The groove depth may be set so as to change along the width direction. For example, the groove depth of the backside sipe 18 may be set to be shallower in the tire width direction central portion and deeper toward the tire width direction end portions, and conversely, the tire width direction central portion is deeper and the tire width direction both ends. You may set it shallower as you go to the club. (Test Example) In Table 1 below, a 10-ton vehicle is equipped with a conventional retreaded tire and a retreaded tire 10 of the present invention in which the wear dimension of the precure tread is 80% of the main groove depth from the time of new article Then, the test results of the braking test of this 10-ton vehicle on a wet road surface are shown. The tire used in the test has a tire size of TBR1000R20, a tread width of 180 mm, four treads on the tread, and surface sipes. The braking distance in Table 1 is an index when the braking distance of the conventional retreaded tire is 100, and the smaller the numerical value, the better.

[0034]

[Table 1]

From the test results shown in Table 1 above, it is clear that the retreaded tire 10 according to the present invention has a shorter braking distance than the conventional retreaded tire and has improved wet performance as compared with the conventional tire. Became.

[0036]

As described above, the precure tread for retreaded tire manufactured by the manufacturing method of the present invention exhibits the maximum wet performance at the end of wear without being affected by the tread pattern on the tread side. A sipe that can be formed can be formed. Therefore,
The retreaded tire of the present invention using the precure tread for a retreaded tire produced by the production method of the present invention has an excellent effect of exhibiting maximum wet performance at the end of wear.

[Brief description of drawings]

1 is a sectional view taken along line 1-1 of FIG. 2 of a retreaded tire according to a first embodiment of the present invention.

FIG. 2 is a plan view seen from the tire tread portion side of the precure tread of the retreaded tire according to the first embodiment of the present invention.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2 of the retreaded tire according to the first embodiment of the present invention.

FIG. 4 is a plan view of a pre-cure tread of a retreaded tire according to a second embodiment of the present invention as seen from the tire tread portion side.

FIG. 5 is a plan view of a pre-cure tread of a retreaded tire according to a third embodiment of the present invention as seen from the tire tread portion side.

FIG. 6 is a plan view of a pre-cure tread of a retreaded tire according to another embodiment of the present invention viewed from the tire tread side.

FIG. 7 is a plan view of a pre-cure tread of a retreaded tire according to another embodiment of the present invention viewed from the tire tread side.

[Explanation of symbols]

 10 retreaded tire 12 tires 14 precure tread for retreaded tire 14A tire tread 16 main groove 16A groove bottom 18 backside sipe 20 short backside sipe

Claims (3)

[Claims] 1. A base of the precure tread for retreaded tire after vulcanization, in which a main groove disposed on the tire tread side is formed at the same time when vulcanizing and molding the precure tread for retreaded tire. A method for producing a precure tread for a retreaded tire, characterized in that a backside sipe whose groove bottom is located closer to the tire tread surface side than the groove bottom of the main groove is formed on the tire side by cutting. 2. A pre-cure tread for retreaded tire manufactured by the method according to claim 1. 3. A retreaded tire characterized in that the precure tread for a retreaded tire according to claim 2 and a base tire are bonded together via an unvulcanized cushion rubber.