JPH0356174B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a cast tire that can be used for four-wheeled motor vehicles, motorcycles, light wheels, agricultural wheels, leisure wheels, and the like.

Cast tires are used that are molded using molding materials such as thermoplastic elastomers and thermoplastic resins. Methods of inserting one or more bead cores into such a cast tire include (i) embedding them at the same time when the tire body is molded, and (ii) forming groove-like recesses in the bead portion during molding of the tire body. Conventionally, two methods have been adopted: a method in which a bead core is fitted into the groove-like recess after the tire body is molded.

However, in method (i) above, it is necessary to firmly hold the bead using a pin or the like to withstand the injection pressure during casting, so there is a problem that pin marks etc. remain on the product. In addition, in method (ii) above,
In order to securely hold the bead core, it is necessary to keep the fit between the bead core and the groove-shaped recess in an optimal state, but it is actually difficult to maintain this fit in an optimal state, and the bead core was often damaged.

This invention was made for the purpose of successfully embedding a bead core in a cast-molded tire using thermoplastic elastomer or thermoplastic resin as a molding material. A recess is formed, and after the tire body is formed, one or more bead cores are fitted into the groove-like recess, and a lid material made of the same material as the tire body is fitted into the groove-like recess. , the lid material and the tire body are welded together using an ultrasonic welder. Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

First, as shown in FIG. 1a, a tire body 1 having a groove-like recess 3 formed around the entire circumference of the bead portion 2 is molded by a known casting method. As the molding material for molding the tire body 1, for example, thermoplastic elastomers such as natural rubber, butadiene rubber, styrene-butadiene rubber, synthetic isoprene rubber, butyl rubber, and thermoplastic resins such as polyurethane can be used. The width of the groove-like recess 3 is preferably about 0.5 to 1 mm wider than the width of the bead core 4 used, and its depth is such that the bead core 4 is located at a predetermined bead core embedding position. Further, the diameter of the groove-like recess 3 is made equal to the diameter of the bead core 4.

Next, as shown in FIG. 1b, a required number of bead cores 4 are fitted into the groove-like recesses 3 of the tire body 1,
The outer side of the tire body 1 is closed with a lid member 5 pre-molded with the same molding material as the tire body 1. That is, the annular lid body 5 having a width approximately equal to the width of the groove-shaped recess 3 is inserted into the groove-shaped recess 3 until it comes into contact with the bead core 4;
The lid body 5 and the tire body 1 are assembled using an ultrasonic welder.
and are melted and bonded. As a result, the lid body 5 is integrated with the tire body 1, the gap disappears, and a cast tire 10 as shown in FIG. 2 in which the bead core 4 is securely held without deformation is obtained. The frequency of ultrasonic welder is 10 to 50K.
Hz is preferable, and during melt bonding, the welded part is heated at 1 to 10 Hz using the backing plate 7 and the horn 6 of the ultrasonic welder.
It is preferable to apply pressure at a pressure of Kg/cm ² .

The method for manufacturing a cast tire according to the present invention involves fitting a bead core into a groove-like recess formed in advance in the bead of the tire, and then inserting a lid body made of the same material as the tire body from the outside. Since the parts are welded and integrated using an ultrasonic welder, the bead core is securely fixed without deformation of the bead part or large gaps. In addition, since the bead is buried after the tire body is formed, there is no need for pins to fix the bead during casting.
No more pin marks remain on the product.

[Brief explanation of drawings]

FIGS. 1a and 1b are explanatory diagrams of a method for manufacturing a cast tire according to the present invention, and FIG. 2 is a sectional view of the obtained cast tire. DESCRIPTION OF SYMBOLS 1... Tire body, 2... Bead part, 3... Groove-shaped recessed part, 4... Bead core, 5... Lid body, 6... Horn, 7
...Packing plate, 10...Casting tire.

Claims (1)

[Claims] 1. A tire body with a groove-like recess that opens outward in the bead part is cast-molded using a thermoplastic elastomer or thermoplastic resin, and one or more bead cores are placed in the groove-like recess of the molded tire body. After fitting, a lid material made of the same material as the tire body is fitted into the groove-like recess, and the lid material and the tire body are welded using an ultrasonic welder to form a cast tire having a bead core. A method for manufacturing a cast tire characterized by obtaining.