JPH1159121A - Solid tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a solid tire which is low in weight and excellent in cushionability, and can be manufactured efficiently in various sizes. SOLUTION: An elastic synthetic resin 2 comprising foaming polyurethane is filled into an annular rubber casing 1 by injection foaming.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid tire mounted on a cart or the like for carrying heavy goods.

[0002]

2. Description of the Related Art In general, tires mounted on small special vehicles such as carts for carrying heavy objects such as beverages in containers and golf luggage or electric scooters for the physically handicapped have no air leakage and are durable. In this case, it is well known that a solid tire that meets the above requirements is applied.

[0003] Such a solid tire is formed by integrally molding a solid annular shape using elastic rubber as a main material, or by fitting a separately formed annular elastic member into a hollow portion of a general-purpose pneumatic tire. there were.

[0004]

However, since the solid portion of the above-mentioned conventional solid tire is required to have strength so as to satisfy the required load-bearing capacity, the molding material necessarily used is high. Specific gravity increases tire weight. Also,
Solid tires also have a problem in that cushioning is inferior to pneumatic tires because vibration from the road surface during running is easily transmitted to the wheels.

[0005] Furthermore, it is necessary to arrange various solid parts to be separately formed according to the size of the tire, and when fitting them into the inside of the casing, the rigid bead part must be forcibly deformed. Is also inferior.

[0006] Therefore, an object of the present invention is to solve the above-mentioned problems and to make a solid tire lightweight and excellent in cushioning properties and to be able to be efficiently manufactured in various sizes.

[0007]

In order to solve the above problems, the present invention employs a construction in which an elastic synthetic resin is foam-filled inside a rubber casing.

[0008]

In the solid tire according to the present invention, the substantial filling amount of the elastic synthetic resin can be reduced in proportion to the foaming amount, the weight can be reduced correspondingly, and the elastic force due to the compressive deformation of the bubbles is added, so that the cushioning property is improved. improves.

The solid tire is completed only by filling and foaming a required amount of the elastic synthetic resin into rubber casings of various sizes, so that the production efficiency is excellent.

[0010]

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

As shown in FIG. 1, the embodiment is a small tire to be mounted on a cart or the like for carrying luggage, in which an elastic synthetic resin 2 made of foamed polyurethane is injected and foamed inside an annular rubber casing 1. It was filled with.

The rubber casing 1 has an outer annular shape and a groove shape in cross section. A bead filler 5 made of a piano wire is buried in a circumferential direction inside a bead portion 4 which is in close contact with a rim 3a of the wheel 3. Inside the tread rubber 6, a breaker 7 in which heat-resistant rubber and cushion rubber are laminated, and a carcass 8 in which several layers of cotton or nylon cords are layered and hardened with rubber are sequentially laminated and adhered. Such a rubber casing 1 can be used by diverting an outer package of a pneumatic tire.

The polyurethane foam to be filled in the casing 1 may be a thermosetting soft foaming foam, and may be a dehydrated polyol, isocyanate, chain extender, cross-linking agent, catalyst, foaming agent, cell size regulator, curing agent. It foams and cures by mixing agents. Examples of the above-mentioned polyol include polyether and polyester, and examples of the isocyanates include tolylene diisocyanate and diphenylmethane diisocyanate. Further, the chain extender may be glycol, diamine, etc., the foaming agent may be carbon dioxide by reaction of water and isocyanate, air, etc., and as the cell size regulator, silicone resin, emulsifier, catalyst, etc. Examples include amines and organic tin compounds.

As the elastic synthetic resin which can be used in the present invention by imparting foaming properties, in addition to the above-mentioned polyurethane, EVA resin (ethylene-vinyl acetate copolymer resin), polyethylene, polystyrene, phenol resin, urea Resins and the like can be mentioned. Furthermore,
A thermoplastic elastomer can be used in the present invention by imparting foaming properties as described above. As such a thermoplastic elastomer, a styrene-butadiene-based, polyester-based, polyethylene-based, or vinyl chloride-based one can be appropriately selected and used.

In the embodiment shown in FIG. 1, an airlight foam manufactured by Nisshinbo Industries, Inc. was used as a commercially available polyurethane foam. In use, a total of 600 g of a main agent composed of a polyisocyanate and a polyol and an auxiliary agent composed of a foaming agent, a catalyst, and the like are used, and these are mixed to prepare a tire (2.50-4).
Size).

As the foam filling method of the above-mentioned elastic synthetic resin 2, a method of injecting into a foaming agent and foaming inside the casing 1 by a reaction injection molding method RIM or continuously injecting the foam immediately after foaming can be adopted. At this time, as shown in FIG. 2, a molding jig mainly composed of a synthetic resin cylindrical body portion 12 having the same diameter as the wheel 3 (see FIG. 1) and a pair of upper and lower flanges 13, as shown in FIG. 2. Use of 14 facilitates appropriate foam molding for a given tire size. Such a molding jig 14 is preferably molded from a material having good releasability with respect to the elastic synthetic resin 2.
For example, a resin obtained by molding a tetrafluoroethylene resin (trade name: Teflon) or an acetal resin (trade name: Duracon), or by applying a release agent to a metal material can be used.

When divided, the molding jig 14 comprises an upper lid portion 14a and a lower main body 14b.
b) A semi-cylindrical notch 15 is formed at one location of the upper edge, and the liquid elastic synthetic resin 2 is injected from here. Also, the main body 1
4b and the center of the lid 14a, a through hole 1
6, a bolt 17 is inserted through the bolt, and the nut 14 is tightened from both ends with nuts 18 so that the main body 14b and the lid 14a are in close contact with each other, and the bead 4 expands at a predetermined distance between the pair of flanges 13 (FIG. 2). (Shown by the dashed line). Further, in order to allow the air remaining in the upper portion of the casing 1 to escape with the expansion of the elastic synthetic resin 2, small holes are appropriately formed in the side of the casing 1 by using a cone or an awl.

In this way, the size between the pair of bead portions 4 is increased by the required size from the size between the pair of rims 3a of the wheel 3 due to the foam filling (see FIG. 3). For example, in a tire of the above size, the distance between the flanges 13 is 64 mm, and the rim 3a
The gap is set to 45 mm, and after curing and curing of the elastic synthetic resin 2, the tire 3 is compressed 19 mm in the width direction by a clamp or the like and the wheel 3 is fitted, so that the bead portion 4 is securely adhered to the rim 3a.

The solid tire manufactured as described above had a load resistance equivalent to that of a pneumatic tire of the same type having an air pressure of 3.5 kg / cm ² and was excellent in cushioning properties.

The above-described procedure of foam filling and mounting on the wheel 3 can be performed in exactly the same manner for casings (not shown) of different sizes, and as shown in FIG. As 11 solid tires,
The weight reduction, cushioning property and production efficiency can be satisfied.

[0021]

According to the present invention, as described above, since the elastic synthetic resin is foam-filled inside the rubber casing, foaming (porosity) of the elastic synthetic resin by the foaming is achieved.
With the ratio, the weight and cushioning properties are remarkably improved, and there is an advantage that it can be efficiently manufactured in various sizes.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment.

FIG. 2 is a longitudinal sectional view showing a foam filling state of an embodiment.

FIG. 3 is an enlarged longitudinal sectional view of a main part of the embodiment before the wheel is mounted.

FIG. 4 is a perspective view showing a use state of the embodiment.

[Explanation of symbols]

 1 casing 2 elastic synthetic resin

Claims (1)

[Claims] 1. A solid tire obtained by foaming and filling an elastic synthetic resin into a rubber casing.