JPH0314402Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a so-called cast tire, which is formed by casting a tire body consisting of a bead part, a side part, and a crown part.

In general, cast tires are made by injecting thermoplastic elastomer or thermosetting resin into a cavity formed by an outer mold and a middle mold to form a toroidal tire outer skin, and separate tire leads as necessary. It is manufactured by configuring it as a tire and attaching it to the tire body. Cast-molded tires are integrally molded products of elastomer or resin, and unlike conventional tires, which are composites of rubber and fiber fabric, they have the disadvantage of low strength and lack of elasticity. In other words, in order to maintain strength in cast tires, it is necessary to use materials with a certain degree of rigidity, but this comes at the expense of elasticity, which is another required characteristic of tires. In other words, the strength and elasticity of the tire,
In other words, durability and ride comfort were essentially contradictory required characteristics.

The present invention provides a cast tire that can improve both of these characteristics by forming predetermined portions into an uneven shape.An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a partial perspective view of a cast tire 1 of the present invention.

The cast tire 1 of the present invention has a tire body 5 consisting of a beat part 2, a side part 3 and a crown part 4, and the crown part 4 has a replaceable tread 6.
is listed. Here, the tire body 5 is integrally molded from the same material, but if necessary, it may be constructed by combining two molded parts on the tire equatorial plane. - A fitting part for attaching the core may be formed. The inner wall w of the side portion 3 of the tire body 5 is formed in an uneven shape so that the tire 1 can be easily bent in the radial direction. As shown in the figure, this uneven shape is formed by arranging grooves 7 in multiple stages that are recessed from the inner surface of the inner wall w, that is, the inner wall surface, and continuous in the tire circumferential direction. In addition, a concave groove 7 extending from one beat part 2 to the other beat part 2 is provided.
Other grooves in the direction perpendicular to the groove may also be used. The formation of the grooves 7 in the circumferential direction of the tire makes it easier for the inner wall w of the side portion 3 to deform under load, greatly reducing the longitudinal spring constant and improving ride comfort.
Furthermore, by forming the grooves 7, relaxation and dispersion of stress can be achieved more effectively, and crack damage caused by stress concentration, which often occurs in conventional tires having smooth inner walls, can be effectively prevented and durability can be improved. Here, the groove depth d of the groove 7 is 50% or less of the side wall thickness D.
The width t of the groove is preferably 5 or more.
It is preferable to set it to mm or less. If the groove depth d exceeds 50% of the side wall thickness D, the side wall strength tends to be weakened, while if it is less than 5%, sufficient deflection cannot be obtained. Further, it is preferable that the width t of the grooves 7 is in contact with each other during bending to maintain rigidity and strength, and for this purpose, the width t is preferably 5 mm or less, particularly in the range of 3 mm to 1 mm. In addition, in the present invention, by providing the groove 7 on the inner wall w of the tire, as described above, a certain amount of
When deformed, the protrusions, which are the tips of the grooves 7 on the inner wall w, come into contact with each other, and further deformation is suppressed, thereby maintaining strength and durability. In addition to the grooves 7 formed on the inner wall w of the side portion 3, similar grooves may also be provided on the outer wall. Furthermore, the concave groove 7 can be formed particularly from the side part 3, that is, the area that contacts the rim flange, to the vicinity of the tire shoulder part 9, but if necessary, it can also be formed in the crown part 4 or the beet part 2 to reduce stress in this area. It can also be relaxed.

FIG. 2 shows another embodiment of the present invention. Here, a groove 7 is formed on the inner wall w of the side part 3, and a groove 7 is also formed on the outer wall near the shoulder part 9, which increases the amount of deformation of the shoulder part 9 and causes stress concentration in this area. This prevents crack damage.

As mentioned above, since the present invention deforms easily in the tire radial direction, at least the inner wall of the side part is formed with an uneven shape, which can improve the poor elasticity, which is a drawback of cast-molded tires, that is, the poor riding comfort. At the same time, durability is further improved because stress concentration is effectively prevented.

[Brief explanation of drawings]

1 and 2 are perspective views showing embodiments of the present invention, respectively. 1... Casting tire, 2... Beat part, 3... Side part, 4... Crown part, 5... Convex part, 6...
Tread portion, 7...concave groove.

Claims (1)

[Scope of utility model registration request] In a cast tire having a replaceable tread on the outside of a crown portion of a tire body consisting of a bead portion, a side portion, and a crown portion, the inner wall of at least the side portion of the tire body is attached to the inner wall in the circumferential direction. A cast tire characterized by having concave and convex grooves that are continuous and recessed from the inner wall surface to make the tire easy to bend in the radial direction.