JP2009298184A - Tread for retreaded tire, and retreaded tire using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tread for a retreaded tire capable of effectively preventing generation of peeling off and wrinkle of an end in a tire width direction of a tread body, and a retreaded tire using this. <P>SOLUTION: A plurality of triangular recession parts 24 arranged in a tire circumferential direction are provided on an inclined surface 21a of the end part in the tire width direction on the tread body 21, and the respective recession parts 24 are formed such that an area of the triangle is gradually reduced toward an inner side in the tire width direction. Therefore, the respective recession parts 24 can be easily stretched/contracted in a tire circumferential direction or a tire radial direction. Thereby, force applied to the end part in the tire width direction of the tread body 21 such as vertical movement at traveling and lateral external force can be absorbed. Further, when the tread body 21 is stuck on a base tire, difference of circumferential length of the end part in the tire width direction of the tread body 21 and a buttress part 13 can be absorbed by expanding/contracting the respective recession parts 24 in the tire circumferential direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a tread for a retread tire used for, for example, a passenger car, a truck, a bus, and the like and a retread tire using the tread.

In general, in heavy-duty pneumatic tires such as buses and trucks, when the remaining groove in the tread reaches the end of its life, the tread surface is cut and buffed, and a new tread is applied to the base tire consisting of the remaining tire body. By attaching it, what was reused as a retreaded tire is known (for example, refer patent document 1). As a tread used for such a retread tire, a so-called precure tread is used in which a tread pattern is formed on the ground contact surface of a tread body made of a belt-like vulcanized rubber having a substantially trapezoidal cross section.
JP 2001-180226 A

  However, the retreaded tire has a problem in that peeling occurs at the bonded end portion in the tire width direction of the tread body due to vertical movement during running or lateral external force. Also, there is a part that absorbs external force during travel by the concave part by providing a concave part that extends continuously in the tire circumferential direction at the end part in the width direction of the tread body and reducing the thickness. There is a problem that wrinkles are generated in the thin portion of the recess and the appearance of the retreaded tire is impaired.

  The present invention has been made in view of the above-mentioned problems, and its object is to provide a tread for a retread tire that can effectively prevent peeling and wrinkling of a tire width direction end of a tread body, and The object is to provide a retread tire using the same.

  In order to achieve the above object, the present invention provides a tread for a retread tire in which a tread body having a main groove on a ground contact surface is formed in a substantially trapezoidal cross section and is attached to a retread tire tire. A plurality of polygonal concave portions arranged in the tire circumferential direction are provided on the inclined surface of the direction end portion, and each concave portion is formed so that the polygonal area gradually decreases toward the inner side in the tire width direction.

  Accordingly, each side of the polygon of each recess is flexed so that each recess easily expands and contracts, and therefore the force in the tire circumferential direction or the tire radial direction generated at the tire width direction end of the tread body is expanded and contracted by each recess. Is absorbed by. Further, when the tread body is attached to the pedestal tire, the difference in circumference between the tire width direction end of the tread body and the pedestal tire is absorbed by shrinking each recess in the tire circumferential direction.

  According to the present invention, it is possible to absorb the force in the tire circumferential direction or the tire radial direction generated at the end of the tread body in the tire width direction, such as vertical movement during driving and lateral external force. Generation of peeling at the direction end can be effectively prevented, and durability can be improved. Also, when attaching the tread body to the base tire, it can absorb the circumferential difference between the tire width direction end of the tread body and the base tire, so that wrinkles are generated at the end of the tread body in the tire width direction. And can be bonded to the base tire, and the appearance can be improved.

  FIGS. 1 to 6 show a first embodiment of the present invention. FIG. 1 is a partial molecular meridian sectional view of a retreaded tire, FIG. 2 is a partially exploded meridian sectional view, and FIG. 3 is a tread for a retreaded tire. FIG. 4 is a front view of a recess, and FIGS. 5 and 6 are diagrams showing test results.

  This retread tire is composed of a base tire 10 obtained by cutting and buffing a tread surface of a tire whose remaining groove has reached the end of life, and a tread 20 having a tread pattern similar to that of a new tire. The tread 20 is used for bonding. Attached to the outer peripheral surface of the base tire 10 via the cushion rubber 30.

  The base tire 10 includes a tread portion 11 whose outer peripheral surface is cut and buffed, sidewall portions 12 formed on both sides in the tire width direction, and a buttress portion formed between the tread portion 11 and the sidewall portions 12. 13 and a bead portion 14 formed on the inner side in the tire radial direction of the sidewall portion 12, and a bead core 14 a is embedded in the bead portion 14.

  The tread 20 is formed in a predetermined length by forming a tread body 21 having a tread pattern on the ground contact surface into a substantially trapezoidal cross section and vulcanizing and molding a band-shaped unvulcanized rubber extruded by an extruder with a mold. Is done. The tread body 21 has a plurality of main grooves 22 extending in the tire circumferential direction, and a plurality of ribs 23 are defined by the main grooves 22. The inclined surfaces 21a on both sides in the tire width direction of the tread body 21 are provided with a plurality of triangular recesses 24 arranged in the tire circumferential direction, and each recess 24 has two apexes at the apexes of the other recesses 24 adjacent to each other. The other apex is in contact with the outer side in the tire radial direction. Each recess 24 is formed in a triangular pyramid shape so that the area of the triangle parallel to the inclined surface 21a gradually decreases inward in the tire width direction, and each side 24a of the triangle, each vertex of the triangle, and the triangle Each side 24b connecting the apex of the cone is curved in a convex shape toward the inside of the recess 24, respectively. In this case, as shown in FIG. 3, each of the recesses 24 has a tire radial direction outer end portion (a triangular apex) at the inner side in the tire radial direction than the height position H of 3.2 mm from the bottom surface of the main groove 22. It is provided so that it may be located in. In addition, each recess 24 has an inner end in the tire width direction (the apex of the triangular pyramid) passing through a height position H of 3.2 mm from the bottom surface of the main groove 22 and a line L1 parallel to the ground contact surface and the inclined surface 21a. Is provided so as to be located on the outer side in the tire radial direction than the line L2 extending inward in the tire radial direction from the intersection point P.

  The cushion rubber 30 is made of a sheet-like unvulcanized rubber and has a width and length equivalent to the tread 20.

  When manufacturing the retreaded tire, the tread 20 is wound around the base tire 10, the tread 20 is brought into close contact with the base tire 10 via the cushion rubber 30, and the cushion rubber 30 is vulcanized by heating and pressurizing. The tread 20 is affixed to the base tire 10. At that time, when the tread 20 is wound around the base tire 10, the inner peripheral surface of the tread body 21 becomes a substantially uniform peripheral length in the tire width direction, whereas the buttress portion 13 of the base tire 10 has an inner side in the tire radial direction. As shown in FIG. 4 (a), the tread body 21 has a plurality of recesses 24 arranged in the tire circumferential direction, so that each recess 24 is shown in FIG. 4 (b). By reducing the circumferential length of the tire width direction end of the tread body 21 along the buttress portion 13 while contracting the tire in the tire circumferential direction, the buttress portion without causing wrinkles at the tire width direction end of the tread body 21 13 is pasted. At that time, each recess 24 contracts when the sides 24 a and 24 b bend toward the inside of the recess 24.

  Further, for example, when the tread body 21 is bent in the tire circumferential direction due to vertical movement or lateral external force during traveling, the external force is absorbed by the respective recesses 24 extending and contracting in the tire circumferential direction as shown in FIG. When the tread body 21 bends in the tire radial direction, each recess 24 expands and contracts in the tire radial direction as shown in FIG.

  About Example 1-4 of this invention and Comparative Examples 1-2, when the external appearance evaluation and the durability test were done, the result shown in FIG.5 and FIG.6 was obtained. Here, the retread tire which does not have a recessed part was used for the comparative example 1, and the retread tire which provided the recessed part extended continuously in the tire circumferential direction at the tire width direction edge part of the tread body was used for the comparative example 2. Further, in Examples 1 and 2, a retread tire in which a plurality of triangular concave portions are arranged in the tire circumferential direction at the tire width direction end portion of the tread body is used. In Example 1, each triangular side is linear. In Example 2, a triangle formed on each side so as to bend inward was used. This test was conducted using a tire having a tire size 11R22.5 mounted on a standard rim.

  In the first test shown in FIG. 5, when running at a speed of 30 km / h and a distance of 10,000 km straight on a test drum at a regular air pressure of JATMA and 140% of the normal load, Comparative Example 1 was a tread. Peeling occurred at the tire width direction end of the main body, and wrinkles occurred in Comparative Example 2, but neither peeling nor wrinkles occurred in Examples 1 and 2. In particular, Example 2 did not peel even when traveling twice as much as Example 1.

  In the second test shown in FIG. 6, slalom running was performed with a test drum at a speed of 50 km / h at a speed of 50 km / h under a normal load condition with JATMA normal pressure. Peeling occurred at the end in the width direction, and wrinkles occurred in Comparative Example 2, but neither peeling nor wrinkles occurred in Examples 1 and 2. In particular, Example 2 did not peel even when traveling twice as much as Example 1.

  As described above, according to the present embodiment, a plurality of triangular recesses 24 arranged in the tire circumferential direction are provided on the inclined surface 21a of the tire width direction end portion of the tread body 21, and each recess 24 is arranged on the inner side in the tire width direction. Since the triangular area is gradually reduced toward the front, each recess 24 can be easily expanded and contracted in the tire circumferential direction or the tire radial direction. Thereby, since the force applied to the tire width direction end part of the tread body 21 such as vertical movement during driving and lateral external force can be absorbed, the occurrence of peeling at the tire width direction end part of the tread body 21 is effective. Therefore, durability can be improved. Further, when the tread body 21 is affixed to the base tire 10, the circumferential length difference between the end portion in the tire width direction of the tread body 21 and the buttress portion 13 can be absorbed by contracting each recess 24 in the tire circumferential direction. Therefore, the tire width direction end portion of the tread body 21 can be bonded to the buttress portion 13 without generating wrinkles, and the appearance can be improved.

  In this case, each concave portion 24 is formed such that each side 24a of the triangle and each side 24b connecting each vertex of the triangle and the apex of the triangular pyramid are curved in a convex shape toward the inside of the concave portion 24, respectively. The recess 24 is easily contracted inward, and the stretchability of the recess 24 can be further increased.

  Further, according to the regulations of the Road Transport Vehicle Law, the depth of the remaining groove of the heavy duty tire when traveling on an expressway is 3.2 mm from the groove bottom to the groove bottom. Even if the tread body 21 is worn to the use limit, it is worn by providing the outer end in the direction so as to be located on the inner side in the tire radial direction from the height position H of 3.2 mm from the bottom surface of the main groove 22. There is an advantage that the contact surface does not reach the outer end of each recess 24 in the tire radial direction, and the tire performance is not adversely affected by the occurrence of uneven wear.

  Further, each of the recesses 24 has a tire width direction inner end passing through a height position H of 3.2 mm from the bottom surface of the main groove 22 and the intersection P between the line L1 parallel to the ground contact surface and the inclined surface 21a. Since it is provided so as to be located on the outer side in the tire radial direction with respect to the line L2 extending inward in the radial direction, even if the tread body 21 is worn to the use limit, the worn grounding surface is the inner end in the tire width direction of each recess 24. Therefore, there is an advantage that it does not reach the position corresponding to the tire radial direction and the recess 24 does not reduce the rigidity of the ground contact surface.

  In the above embodiment, each side of the recess 24 is curved, but a part or all of each side may be formed in a straight line.

  In the above embodiment, the concave portion 24 is formed in a triangular pyramid shape. However, the inclined surface 21a of the tread body 21 is formed on the apex side of the triangular pyramid like the concave portion 25 shown in the second embodiment of FIG. You may form so that it may have the parallel bottom face 25a. Furthermore, each triangular vertex is chamfered like a recess 26 shown in the third embodiment of FIG. 8, or is formed like a square like a recess 27 shown in the fourth embodiment of FIG. You may make it do. In this case, the recess may have other shapes as long as it is polygonal, but a hexagon or less is preferable in order to sufficiently bend each side of the recess.

Partial molecular meridian direction sectional view of a retreaded tire showing a first embodiment of the present invention Partially disassembled meridional section of retreaded tire Cross section of the main part of tread for retread tires Front view of recess Figure showing the results of the first test Figure showing the results of the second test The front view of the recessed part which shows the 2nd Embodiment of this invention The front view of the recessed part which shows the 3rd Embodiment of this invention The front view of the recessed part which shows the 4th Embodiment of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Base tire, 20 ... Tread, 21 ... Tread body, 21a ... Inclined surface, 24 ... Recess, 24a, 24b ... Side of recess, 25, 26, 27 ... Recess.

Claims (5)

In the tread for rehabilitated tires, the tread body having a main groove on the ground contact surface is formed in a substantially trapezoidal cross section and is attached to the retired tire base tire,
Provided with a plurality of polygonal recesses arranged in the tire circumferential direction on the inclined surface of the tire width direction end of the tread body,
A tread for retread tires, characterized in that each recess is formed so that the polygonal area gradually decreases toward the inside in the tire width direction. The tread for retread tire according to claim 1, wherein each of the recesses is formed such that at least one side of the polygon is curved in a convex shape toward the inside of the recess. Each of the concave portions is provided such that an end portion on the outer side in the tire radial direction is located on the inner side in the tire radial direction with respect to a height position of 3.2 mm from the bottom surface of the main groove. Tread for retread tires as described. Each of the recesses has an inner end in the tire width direction from a line extending inward in the tire radial direction from an intersection of a line parallel to the ground surface and an inclined surface passing through a height position of 3.2 mm from the bottom surface of the main groove. The tread for retread tires according to claim 3, wherein the tread is also provided so as to be positioned on the outer side in the tire radial direction. A retreaded tire using the retreaded tire tread according to claim 1, 2, 3 or 4.

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