JPH0694180B2 - Tread rubber body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a tread rubber body that can form a tread surface of a retreaded tire, and prevents occurrence of interfacial cracking between a base tire and the tread rubber body. The present invention relates to a tread rubber body that can improve the durability of a retreaded tire.

[Conventional technology]

In recent years, in order to effectively use resources, old tires with worn tread surfaces are scraped off from the tread surface layer to form base tires, and a new tread rubber body is wrapped around the outer peripheral surface of the base tires to rehabilitate the tread portion. So-called retreaded tires are becoming popular.

[Problems to be Solved by the Invention]

Conventionally, in a retreaded tire, a new tread rubber body previously vulcanized and molded is circulated around the outer peripheral surface of the base tire, vulcanized and bonded to the base tire, and integrated.
The retreaded tire formed in this manner has a problem that interface bending occurs at both ends of the joint due to the flexure that occurs during running of the tire, resulting in poor durability.

In order to solve the above-mentioned problems, the applicant has disclosed that, as disclosed in Japanese Examined Patent Publication No. 63-44561 and as shown in FIG. 4, the side walls b, b of the tread a are gently sloped on the side of the base tire c. A tread for rehabilitation provided with d is proposed. In this structure, although the interfacial cracks can be prevented, the suppression of cracks that tend to occur in the vicinity of the joints of the buttress portion is not improved and the above problems have not been solved.

The inventor has conducted extensive research to solve the above problems, and by providing a wing portion that can cover the buttress portion on both sides of the base portion that forms the tread surface, damage to the buttress portion can be prevented, and durability of the retreaded tire is improved. It has been found that this can be further improved.

The present invention is based on the fact that wing portions are provided on both sides of the base portion, and further, the base portion, each cross-sectional dimension of the wing portion, and the crossing angle are regulated.
An object of the present invention is to provide a tread rubber body that can improve wear resistance as well as durability.

[Means for Solving the Problems]

The present invention is a long tread rubber body for a retreaded tire whose upper surface forms a tread surface of the tire by joining and integrating the lower surface by vulcanization around the outer peripheral surface of the base tire, A sloped surface that is attached to the outer peripheral surface and has both ends in the width direction that incline upward in the vicinity of the outer peripheral point (P) of the outer peripheral surface in the axial direction of the tire and that has an inclination angle (α) with respect to a line segment perpendicular to the lower surface; And a lower surface that is substantially flush with the lower surface of the base and that is thinner than the base and extends beyond the outer edge point (P) by the attachment to the buttress portion of the base tire. And the outer end portion is provided with a wing portion having a slope inclined in the same direction as the slope of the base portion, and the base portion has the same or thicker thickness from the tire equator toward the outer end in the width direction. The top surface is against the horizon The blade is inclined at an inclination angle (β), and the upper surface is inclined at an inclination angle (γ) with respect to the horizontal line in the direction in which the thickness becomes the same or thickens toward the outer end in the width direction, and the inclined surface of the base portion. And the upper surface of the wing portion are continuous with an arc having a radius (R), the tilt angle (α) is 5 to 60 °, the tilt angle (β) is 0 to 30 °, and the tilt angle γ is 0 to 45. °, the width (A) of the wing portion in the width direction from the outer edge point (P) is 2 to
50mm, the width (B) of the blade slope in the width direction is 1 to 13mm, and the ratio of the minimum blade thickness (T1) to the base thickness (T0) is T1 / T0.
Is a tread rubber body having a radius greater than 0 and 0.5 or less and a radius R of 5 mm or more and a radius of an inscribed circle between the slope of the base and the upper surface of the blade.

In addition, the wing portion has a single or multiple ridge groove extending in the longitudinal direction on the upper surface thereof, and the groove depth (T2) of the ridge groove is 0.1 times the minimum thickness (T1) of the wing portion. It is preferably not less than 0.5 times and not more than 0.5 times. Tread rubber body.

[Action]

Since the base portion is provided with the 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.

Further, since the intersection angle at which the dimensions and the constituent surfaces intersect for the base portion and the wing portion is regulated as described above, the occurrence of cracks due to tire running at the interface between the base tire and the base portion, and the occurrence and growth of cracks in the buttress portion of the base tire. Can be prevented and durability can be improved.

Further, since the upper surface of the base portion is inclined from the tire equator toward the outer end in the direction in which the thickness is the same or thickened, it is caused by fixing the wing portion when the tread rubber body is joined to the base tire. It is possible to prevent the middle bulge of the upper surface and to flatten the upper surface by fixing the tread rubber body to the base tire, to eliminate the defect of the ground contact surface, which has been a defect of the conventional retreaded tire, and to improve the durability.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In the figure, a tread rubber body 1 is an outer peripheral surface 3 of a base tire 2.
Is a long rubber body used for a retreaded tire in which the upper surface 5 forms a tread surface by joining the lower surface 4 to the outer peripheral surface 3 and the base tire 2 is an old tire whose tread surface is worn, It is formed by removing the tread outer layer portion with a buff.

The tread rubber body 1 includes a base portion 6 located inside the tire axial outer edges P of the outer peripheral surface 3 of the base tire 2 and the base portion 6.
A pair of wings 7 extending from the outer edges P, P to the outside,
7 and.

The base portion 6 has both ends in the width direction of the lower surface 4 located near the outer edge points P, P of the base tire 2, and 5 to 60 ° with respect to line segments Y, Y perpendicular to the lower surface 4 from the both ends. A slope 9 having an inclination angle α of

Further, the upper surface 5 is inclined from the tire equator C toward the outer end in the width direction such that the rubber thickness between the lower surface and the lower surface is the same or becomes thicker, and the upper surface is inclined at 0 to 30 ° with respect to the horizontal line X. It inclines at an angle β and intersects the slope 9.

The wing portion 7 has a lower surface 11 below the base 6 and substantially flush with the lower surface 4 of the base 6, and is thinner than the base 6 and extends outward in the width direction and at the outer end thereof. 6
It has a slope 12 which is inclined in the same direction as the slope 9.

Further, in the wing portion 7, the upper surface 13 inclines toward the outer end in the width direction at an inclination angle γ of 0 to 45 ° with respect to the horizontal lines X ′ and X ′ in the direction in which the thickness from the lower surface 11 becomes the same or becomes thicker. On the other hand, the upper surface 13 of the wing 7 is at least 5 mm from the slope 9 of the base 6 and the base 6
The inclined surface 9 and the upper surface 13 of the blade portion 7 are connected by an arc having a radius R which is equal to or less than the radius of the inscribed circle.

Further, the wing portion 7 has a length of the lower surface 11, that is, the outer edge point P.
The width A of the blade portion 7 in the width direction is defined in the range of 2 to 50 mm, while the length B of the slope 12 of the blade portion 7 in the width direction is defined in the range of 1 to 13 mm. Also, the wing portion 7 is a sloped surface 9 of the base 6 on the upper surface 13.
The thickness at the intersection Q with, that is, the minimum thickness T1 of the wing 7,
The base 6 at the outer end E where the slope 9 and the upper surface of the base 6 intersect
The ratio T1 / T0 with respect to the thickness T0 is larger than 0 and 0.5 or less.

Further, the upper surface 13 of the wing portion 7 is provided with a single-line or multiple-line, in the present embodiment, three line grooves 15, 15, 15 extending in the longitudinal direction. The groove depth T2 of the groove 15 is the minimum thickness T1 of the blade portion 7.
0.1 times or more and 0.5 times or less. Such groove
Providing 15 facilitates bending deformation of the wing 7,
The lower surface 11 of the wing portion 7 can be attached to the buttress portion 14 of the base tire 2 more easily and reliably.

In this embodiment, lower grooves 17 are provided on the upper surface 5 of the base 6 so as to extend in the longitudinal direction and finish to form tread grooves on the tread surface.

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

If the inclination angle α of the base portion 6 is less than 5 °, the blade portion 7 is vulcanized.
When the tire is bent along the buttress portion 14, the outer peripheral surface 3 of the base tire 6 is warped in the vicinity of the outer edge point P, so that stress is generated at the interface between the tread rubber body 1 and the base tire 2, and cracks occur. Damage easily occurs such as Conversely 60
If it exceeds 0, the width dimension of the upper surface 5 of the base portion 6, that is, the tread width of the rehabilitated tire becomes small, resulting in poor wear resistance when the tire is used.

The inclination angle β of the upper surface 5 of the base portion 6 is for controlling the ground contact area of the rehabilitated tire, and when the tread rubber body 1 is joined to the base tire 2, the upper surface is bent by bending the wing portion 7. 5 is transformed into a middle bulge. When the inclination angle β exceeds 0 ° and the upper surface 5 swells in the middle, the ground contact area becomes small and the grip performance deteriorates. On the other hand, when the inclination angle β exceeds 30 °, the upper surface is even joined to the base tire 2 and integrated. No. 5 has a concave shape, which deteriorates the steering stability and tends to cause uneven wear.

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

If the length of the wing 7 in the width direction is less than 2 mm, the effect of providing the wing 7 is not effective, and if it exceeds 50 mm, waviness occurs at the outer end during joining with the base tire 2 and vulcanization. It will be difficult.

When the width B of the sloped surface 12 of the blade portion 7 in the width direction is less than 1 mm, the appearance of the finished retread tire is deteriorated, while when it exceeds 13 mm, the outer end portion of the blade portion 7 is wavy during vulcanization molding.

Ratio T1 / T0 of minimum thickness T1 of wing 7 to thickness T0 of base 6
When the value exceeds 0.5, the rigidity of the blade portion 7 in the tire radial direction increases, and it becomes difficult to attach the lower surface 11 of the blade portion 7 to the buttress portion 14.
In addition, it is easy to peel off during traveling, and the effect of providing the wing 7 cannot be expected.

The radius connecting the sloped surface 9 of the base portion 6 and the upper surface 13 of the blade portion 7 is for facilitating the attachment to the buttress portion 14 of the blade portion 7. If the radius is less than 5 mm, cracks may occur due to bending of the blade portion 7. If it is made larger than the inscribed circle between the inclined surface 9 and the upper surface, the bending rigidity of the blade portion 7 increases, and it becomes difficult to attach it to the buttress portion 14.

If the groove depth T2 of the groove 15 provided on the blade 7 is less than 0.1 times the minimum thickness T1 of the blade 7, the effect of providing the groove 15 with a shallow groove bottom is small, and conversely 0.5 times. If it exceeds, the wing portion 7 may be damaged during the adhesion to the base tire 2.

〔The invention's effect〕

As described above, the tread rubber body of the present invention has the wing portions extending on both sides of the base portion, so that the buttress portion of the base tire can be covered with the wing portions, and the dimensions of the base portion and the wing portions can be covered. By controlling the angle and the angle, it is possible to prevent the occurrence of cracks from the interface between the inner surface of the tread rubber and the outer peripheral surface of the base tire, which has been apt to occur in the conventional retreaded tire, and to prevent the growth thereof, and the durability of the retreaded tire. To 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 recessed, in the retreaded tire using the tread rubber body of the present invention, the ground contact surface increases and the wear resistance increases.

As described above, the tread rubber body of the present invention can form a retreaded tire having improved durability.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view showing a main portion of the same, 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, and FIG. 4 is a sectional view showing a conventional technique. 2 ... Stand tire, 3 ... Outer peripheral surface, 4 ... Bottom surface, 5 ... Top surface, 6 ... Base portion, 7 ... Wing portion, 9 ... Slope surface, 11 ... Bottom surface, 12 ... Slope surface, 13 ... … Top surface, 14 …… Butless part, 15 …… Slit groove, A …… Width direction length of the wing part, B …… Width direction width of the slope of the wing part, P …… Outer edge point, R …… Radius, T0 ... Base thickness, T1 ... Minimum thickness of blade, T2 ... Groove depth, XX, YY ... Line segment, α ... Inclination angle, β ... Inclination angle, γ ... Tilt angle.

Claims (2)

[Claims] 1. A long tread rubber body for a retreaded tire, the upper surface of which serves as a tread surface of the tire by being integrated with the outer peripheral surface of the base tire by vulcanization to join and integrate the lower surface. A sloped surface that is attached to the outer peripheral surface of the tire and has both ends in the width direction inclined inward toward the outer peripheral point (P) of the outer peripheral surface in the axial direction and having an inclination angle (α) with respect to a line segment perpendicular to the lower surface. And a lower portion of the base portion that is substantially flush with the lower surface of the base portion, is thinner than the base portion, and is attached to the buttress portion of the base tire beyond the outer edge point (P) by the attachment. Along with the wings having a slope extending in the same direction as the slope of the base at the outer end and the base, the base is in the same thickness direction or thicker from the tire equator toward the outer end in the width direction. The upper surface is against the horizon The blade is inclined at an inclination angle (β), and the wing portion has an upper surface inclined at an inclination angle (γ) with respect to the horizontal line in a direction in which the thickness becomes the same or thickens toward the outer end in the width direction, and the inclined surface of the base portion. And the upper surface of the wing portion are continuous with a circular arc having a radius (R), the inclination angle (α) is 5 to 60 °, the inclination angle (β) is 0 to 30 °, and the inclination angle (γ) is 0. ~ 45
°, the width (A) in the width direction of the blade from the outer edge point (P) is 2 to 50 mm, and the length (B) in the width direction of the slope of the blade is 1 to 13 m.
m, ratio T between the minimum thickness of the wing (T1) and the thickness of the base (T0)
1 / T0 is greater than 0 and 0.5 or less, and the radius R is 5 mm or more and less than or equal to the radius of the inscribed circle between the slope of the base and the upper surface of the blade. 2. The blade portion is provided with a single or a plurality of groove grooves extending in the longitudinal direction on the upper surface thereof, and the groove depth (T2) of the groove is the minimum thickness (T1) of the blade portion. ) More than 0.1 times
The tread rubber body according to claim 1, which is 0.5 times or less.