JPH04153029A - Tread rubber body - Google Patents

Abstract

PURPOSE:To improve durability while also enhancing abrasion resistance by installing blade sections extended on both sides of a base section, covering the buttress section of a base tire with the blade sections and regulating the constitutional size and angles of the base section and the blade sections. CONSTITUTION:Both ends in the cross direction of an underside 4 is positioned near the peripheral point P of a base tire in a base section 6, and an inclined plane 9 having an inclination alpha of 5-60 deg. to a segment Y rectangular to the underside 4 from both ends is formed. A top face 5 is inclined at an inclination beta of 0-15 deg. to a horizon X in the direction that rubber thickness between the top face and the underside is made the same or thickened toward an outer end in the cross direction form the equator of the tire in the tip face 5, and crossed with an inclined plane 9. A blade section 7 has an underside 11 having approximately the same surface as the underside 4 of the base section 6 in the lower section of the base section 6, is made thinner than the base section 6 and is extended to the outside in the cross direction, and has an inclined plane 12 tilted in the same inclination as the inclined plane 9 of the base section 6 in an outer end section. A top face 13 is tilted at an inclination gamma or of 0-45 deg. to a horizon X' in the direction that thickness from the underside 11 is made the same or thickened toward an outer end in the cross direction in the blade section 7, and the top face 13 of the blade section 7 is connected to the inclined plane 9 of the base section 6 at a distance of 5mm or more and in a circular arc having a radius R to the inclined plane 9 of the base section 6.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a tread rubber body capable of forming the tread surface of a retreaded tire, which prevents the occurrence of interface cracks between the base tire and the tread rubber body. This invention relates to a tread rubber body that can improve the durability of retreaded tires.

[Conventional technology]

In recent years, in order to effectively utilize resources, the tread surface layer of old tires with worn tread surfaces has been scraped off to form base tires, and a new tread rubber body has been wrapped around the outer circumferential surface of the base tires. Retreaded, so-called retreaded tires are becoming popular.

[Problem to be solved by the invention]

Conventionally, retreaded tires have been formed by vulcanizing and bonding a new tread rubber body around the outer peripheral surface of a base tire by vulcanizing it and integrating it with the base tire.

Retreaded tires formed in this manner have a problem in that interfacial cracks occur at both ends of the joint due to deflection that occurs when the tire runs, resulting in poor durability.

In order to solve the above problems, the applicant proposed
As disclosed in Japanese Patent Application No. 61 and shown in FIG. 4, a retreading tread is proposed in which the side wall surfaces S and B of the tread a are provided with a gentle slope d located on the base tire C side.

In this structure, although the interface cracks can be prevented, the prevention of cracks that tend to occur near the joints of the buttress parts is not improved, and the above problems have not been solved.

In order to solve the above-mentioned problems, the inventor conducted repeated research and found that by providing wing sections that can cover the buttress section on both sides of the base forming the tread surface, damage to the buttress section can be prevented and the durability of retreaded tires can be improved. He discovered the scales to further improve his skills.

The present invention is based on the fact that wing parts are provided on both sides of the base part, and that the cross-sectional dimensions and intersection angles of the base part and the wing part are regulated.
The object of the present invention is to provide a tread rubber body that can improve durability and wear resistance.

[Means to solve the problem]

The present invention relates to a long tread rubber body for a retreaded tire, the upper surface of which forms the tread surface of the tire by making the body go around the outer circumferential surface of a base tire and joining and integrating the lower surface by vulcanization. a slope attached to the outer circumferential surface and having both ends in the width direction inclined upward and inward near the outer edge point (P) of the outer circumferential surface in the tire axial direction and having an inclination angle (α) with respect to a line segment perpendicular to the lower surface; and a lower surface of the base that is substantially flush with the lower surface of the base, is thinner than the base, and is attached to the outer edge point (P).
) extending outward to the buttress portion of the base tire and having a slope at the outer end inclined in the same direction as the slope of the base, and the base extends from the tire equator toward the outer end in the width direction. The upper surface is inclined at an inclination angle (β) with respect to the horizontal line in a direction in which the thickness is the same or becomes thicker, and the wing portion is in a direction in which the thickness is the same or becomes thicker toward the outer end in the width direction. The upper surface is inclined with respect to the horizontal line at an inclination angle (γ), and the slope of the base and the upper surface of the wing are continuous in an arc of radius (R), while the above-mentioned inclination angle (α) is 5 to 600, and the above-mentioned inclination is The angle (β) is 0 to 30 degrees, the inclination angle γ is 0 to 45 degrees, and the length (A) in the width direction of the wing from the outer edge point (P) is 2 to 5 degrees.
0mm.

The widthwise length (B) of the slope of the wing section is 1 to 13 mm.

The ratio Tl/TO between the minimum thickness of the wing part (T1) and the thickness of the base part (T0) is greater than 0 and 0.5 or less, the radius R is 5 mm or more, and the slope of the base part and the upper surface of the wing part are This is a tread rubber body whose radius is less than or equal to the radius of the inscribed circle.

Further, the wing portion has a single groove or a plurality of grooves extending in the longitudinal direction on its upper surface, and has a groove depth (T2) of the groove.
is 0.1 times or more the minimum thickness (T1) of the wing portion and 0,
It is preferable to set it to 5 times or less.

Tread rubber body.

[Effect]

Since the base is provided with a wing portion that extends beyond the outer edge point P on the outer peripheral surface of the base tire, the wing portion can cover the buttress portion of the base tire.

In addition, because the dimensions of the base and wing portions and the intersection angles of the constituent surfaces are regulated as described above, cracks may occur at the interface between the base tire and the base due to tire running, and cracks may occur and grow in the buttress portion of the base tire. can be prevented and durability can be increased.

Furthermore, since the upper surface of the base slopes from the tire equator toward the outer edge so that the thickness remains the same or becomes thicker, this problem occurs when the wing section is fixed when the tread rubber body is joined to the base tire. This prevents the upper surface from bulging and makes the upper surface flat due to the adhesion of the tread rubber body to the base tire, eliminating defects in the ground contact surface that were conventionally considered a drawback of retreaded tires, and increasing durability.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

In the figure, the tread rubber body 1 is the outer peripheral surface 3 of the base tire 2.
It is a long rubber body used for retreaded tires in which the upper surface 4 forms a tread surface by joining the lower surface 3 to the outer circumferential surface 3, and the stand tire 2 is used for old tires with worn tread surfaces. It is formed by removing the outer layer of the tread with a puff.

The tread rubber body 1 includes a base 6 located inside the axially outer edge PSP of the outer circumferential surface 3 of the base tire 2;
a pair of wing portions 7 extending beyond the outer edges P and P;
7.

The base 6 has both ends in the width direction of the lower surface 4 located near the outer edge point PSP of the base tire 2, and is inclined at 5 to 60 degrees with respect to Y, a line segment Y perpendicular to the lower surface 4 from the both ends. It comprises a slope 9 having an angle α.

Further, the upper surface 5 has an inclination angle of 0 to 15 degrees with respect to the horizontal line X1X, so that the rubber thickness between the tire equator C and the lower surface is the same or becomes thicker toward the outer end in the width direction. It slopes and intersects the slope 9.

The wing section 7 has a lower surface 11 located below the base section 6 and substantially flush with the lower surface 4 of the base section 6, is thinner than the base section 6, extends outward in the width direction, and has the base section at the outer end. A slope 12 inclined in the same direction as the slope 9 of No. 6 is provided.

In addition, the wing portion 7 has an upper surface 13 aligned with the horizontal line x' in a direction in which the thickness from the lower surface 11 is the same or becomes thicker toward the outer end in the width direction.
x' at an inclination angle γ of 0 to 45°, while the upper surface 13 of the wing portion 7 is 5 mm away from the slope 9 of the base 6.
The slope 9 of the base portion 6 and the upper surface 13 of the wing portion 7 are connected by an arc having a radius R that is equal to or less than the radius of the inscribed circle.

Furthermore, the length of the lower surface 11 of the wing section 7, that is, the length A in the width direction of the wing section 7 from the outer edge point P, is in the range of 2 to 50 mm, while the width direction of the slope 12 of the wing section 7 is in the range of 2 to 50 mm. length B from 1 to
It is specified within a range of 13 mm.

The wing portion 7 has a thickness at the intersection Q of the upper surface 13 with the slope 9 of the base 6, that is, the minimum thickness T1 of the blade 7 and the slope 9 of the base 6.
The ratio Tl/To of the thickness To of the base portion 6 at the outer end E where the upper surfaces intersect is greater than O and 0.5 or less.

Further, in the upper surface 13 of the wing portion 7, a single groove or a plurality of grooves 15, 15, and 15 (three grooves in this embodiment) extending in the longitudinal direction are recessed. Further, the groove depth T2 of the groove 15 is set to be at least 0.1 times and at most 0.5 times the minimum thickness T1 of the wing portion 7. By providing such grooves 15, bending deformation of the wing section 7 becomes easier, and attachment of the lower surface 11 of the wing section 7 to the buttress section 14 of the base tire 2 can be made easier and more reliable.

In this embodiment, the upper surface 5 of the base 6 is provided with a lower groove 17- which extends in the longitudinal direction and can form a tread groove on the tread surface by finishing.

Next, each regulation value of each of the tread rubber bodies 1 will be described.

If the inclination angle α of the base portion 6 is less than 5°, the wing portion 7 will be removed during vulcanization.
When the base tire 6 is bent along the buttress portion 14
Since the outer circumferential surface 3 of the tire is reversely warped near the outer edge point P, stress is generated at the interface between the tread rubber body 1 and the base tire 2, and damage such as cracks is likely to occur. On the contrary, 6
If the angle exceeds 0°, the width of the upper surface 5 of the base 6, that is, the tread width of the retreaded tire becomes small, resulting in poor wear resistance during use of the tire.

The inclination angle β of the upper surface 5 of the base 6 is for regulating the ground contact area of the retreaded tire, and when the tread rubber body 1 is joined to the base tire 2, the upper surface is 5 will be deformed into a middle bulge. If the inclination angle β exceeds 00 and the upper surface 5 becomes bulged in the middle, the contact area becomes small and the grip performance decreases, while if it exceeds 30°, even after being joined and integrated with the base tire 2. The upper surface 5 has a concave shape, which reduces steering stability and tends to cause uneven wear.

If the inclination angle γ of the upper surface of the wing section 7 becomes a negative inclination angle, the wing section 7
The thickness of the outer end portion is insufficient, and the strength of the wing portion 7 is reduced. On the other hand, if the angle exceeds 45°, the rigidity of the wing portion 7 increases when it is attached to the base tire, making the work difficult.

Furthermore, if the length in the width direction of the wing section 7 is less than 2 mm, the effect of providing the wing section 7 is not achieved, and if it exceeds 50 mm, undulations will occur at the outer end when joining with the base tire 2 and during vulcanization, making the work difficult. It becomes difficult.

When the length B of the slope 12 of the wing portion 7 in the width direction is less than 1 mm,
While the appearance of the finished retreaded tire deteriorates, the 13mm
If it exceeds this value, waving will occur at the outer end of the wing portion 7 during vulcanization molding.

Ratio T of the minimum thickness T1 of the wing portion 7 to the thickness To of the base portion 6
When l/To exceeds 0.5, the rigidity of the wing section 7 in the tire radial direction increases, making it difficult to attach the lower surface 11 of the wing section 7 to the buttress section 14, and also making it easy to peel off during running. I can't expect that.

The radius connecting the slope 9 of the base 6 and the upper surface 13 of the wing section 7 is for smooth attachment to the buttress section 14 of the wing section 7, and if it is less than 5 mm, cracks will occur due to bending of the wing section 7. If the inscribed circle between the slope 9 and the upper surface is increased, the bending rigidity of the wing portion 7 increases, and the buttress portion 14
It becomes difficult to attach to the

Furthermore, if the groove depth T2 of the groove 15 provided in the wing section 7 is less than 0.1 times the minimum thickness T1 of the wing section 7, the groove bottom will be shallow and the groove 15
The effect of providing is small, and conversely, if it exceeds 0.5 times, the wing portion 7 may be damaged during the adhesion to the base tire 2.

〔Effect of the invention〕

As shown above, the tread rubber body of the present invention has wing parts extending on both sides of the base, so the buttress part of the base tire can be covered by the wing parts, and the structural dimensions of the base and wing parts, By regulating the angle and angle, it is possible to prevent the occurrence and growth of cracks at the interface between the inner surface of the tread rubber body and the outer peripheral surface of the base tire, which tend to occur in conventional retreaded tires, and improve the durability of retreaded tires. improve.

Furthermore, since the inclination angle of the upper surface of the base is restricted to the negative side where the central portion of the tread is concave, in a retreaded tire using the tread rubber body of the present invention, the ground contact area increases and the wear resistance increases.

In this way, the tread rubber body of the present invention can form a retreaded tire with increased durability.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a cross-sectional view in the width direction showing an enlarged main part thereof, and FIG. 3 is a retreaded tire formed using the tread rubber body of the present invention. FIG. 4 is a sectional view showing an example of the prior art. 2-1 tire, 3-, -outer circumferential surface, 4--bottom surface, 5--top surface, 6----base, 7-
-wing part, 9-9 slope, 11=-lower surface, 12-
Slope, 13-Top surface, 14-Buttress portion, 15-
Single groove, 8- Length in the width direction of the wing section, B-1. Length in the width direction of the slope of the wing section, P, - = Outer edge point, R - Radius, To -, Thickness of the base, Tl - minimum thickness of the wing,
T2- Groove depth, XXXYY-0- line segment,
α−～−Inclination angle, β−・−・Inclination angle,
γ---Tilt angle. Patent applicant Sumitomo Rubber Industries Co., Ltd. Agent
Patent Attorney Tadashi Naemura Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1 A long tread rubber body for a retreaded tire whose upper surface forms the tread surface of the tire by wrapping it around the outer peripheral surface of the tire and joining and integrating the lower surface by vulcanization, comprising: It is attached to the outer circumferential surface of the base tire and both ends in the width direction are inclined upwardly and inwardly near the outer edge point (P) of the outer circumferential surface in the tire axial direction, and at an inclination angle (α) with respect to a line segment perpendicular to the lower surface. and a buttress of the base tire, which is thinner than the base and extends beyond the outer edge point (P) by the attachment. and a wing part having a slope extending in the outer end thereof and tilting in the same direction as the slope of the base part, and the base part has the same thickness or becomes thicker from the tire equator toward the outer end in the width direction. The upper surface is inclined at an inclination angle (β) with respect to the horizontal line in the direction, and the upper surface is inclined at an inclination angle (β) with respect to the horizontal line in the direction in which the thickness of the wing portion is the same or becomes thicker toward the outer end in the width direction. Moreover, the slope of the base and the upper surface of the wing are continuous in an arc of radius (R), while the inclination angle (α) is 5 to 60°, and the inclination angle (β
) is 0 to 30 degrees, the inclination angle (γ) is 0 to 45 degrees, and the length (A) in the width direction of the blade from the outer edge point (P) is 2 to 5
0mm, the width direction length of the slope of the wing (B) is 1 to 13m
m, the ratio T1/T0 of the minimum thickness of the wing part (T1) and the thickness of the base part (T0) is greater than 0 and 0.5 or less, the radius R is 5 mm or more, and the slope of the base part and the upper surface of the wing part A tread rubber body whose radius is less than or equal to the radius of the inscribed circle. 2. The wing section has a single groove or multiple grooves extending in the longitudinal direction on its upper surface, and has a groove depth (T2) of the groove.
) is 0.1 times or more the minimum thickness (T1) of the wing portion and 0
．． The tread rubber body according to claim 1, wherein the tread rubber body is 5 times or less.