JPH06327844A - Tire for toy vehicle and manufacture thereof - Google Patents

Abstract

PURPOSE:To secure both the rigidity for supporting the weight of a toy vehicle, and the grip force for enabling high-speed cornering by providing an outer skin consisting of a soft rubber for securing a grip force to a road surface, and by foaming a sponge body inside the outer skin, so that the sponge body can be integrated with the outer skin. CONSTITUTION:The tire to be used for a toy vehicle such as a radio-controlled car is made up from an outer skin 2 of a soft rubber material, and a sponge body 3 situated inside the outer skin 2 and integrated with the outer skin 2; and the sponge body 3 is supported by a wheel 4. The outer skin 2 is formed a natural rubber so as to have a thickness of approximately 1.5mm or less, and the sponge body 3 is formed by using synthetic resins such as urethane resin, polyvinyl chloride resin, and polystyrene resin. Such a tire like this is manufactured by arranging the outer skin 2 formed by a mold inside a mold with a core, and by foaming the resin poured between the inside of the outer skin 2 and the core so as to form a sponge body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire for a toy car such as a radio control and a method for manufacturing the tire.

[0002]

2. Description of the Related Art Some toy cars such as radio control cars have a body weight of 1.0 to 2.0 kg and can run at a maximum speed of 50 km / h, and moreover, they are capable of running straight curved lines on various road surfaces such as asphalt roads, concrete roads and sands. Required. Therefore, the tire performance is also high level.

Two basic requirements for tires are gripping the road surface and rigidity for supporting the weight of the vehicle body and absorbing vibrations from the road surface. The grip force of the former becomes higher as the rubber is made softer, and the rigidity of the latter becomes higher as the rubber is made harder. That is, if a soft rubber is used to increase the grip force, it is not possible to obtain sufficient rigidity to support the weight of the vehicle body. Conversely, if the necessary rigidity is maintained, the grip force will be weak and tire slip will not occur. It is easy to occur. In other words, tires balance the contradictory properties of grip and rigidity to bring out a high level of performance.

As typical examples of conventional toy car tires, hollow rubber tires and solid sponge tires in consideration of the balance of the above-mentioned contradictory properties are mainly used. Hollow rubber tires have increased gripping power by making them softer, but there is a limit to their flexibility in order to ensure rigidity, and as a result, gripping force is better than that of solid sponge tires that have been put to practical use. The reality is that is low. With solid sponge tires, the eyes of the bubbles on the sponge surface catch on the fine irregularities on the road surface to ensure grip. For this reason, the gripping force is reduced when the road surface has no unevenness (such as vinyl tiles) or the fine unevenness of the road surface does not match the size of the eyes of the sponge. Separately from this, between the radio control fans, a rubber tube is fitted on the surface of the solid sponge tire, and the material of the rubber tube is changed according to the road surface condition to satisfy the basic requirements of the tire described above.

[0005]

It is noted that the above-mentioned capped tire in which a rubber tube is fitted into the solid sponge tire draws out the special features of the sponge material and the rubber material and applies it. However, this capped tire
A commercially available solid sponge tire is fitted with a rounded soft rubber tube, but the inner diameter of the rubber tube is made smaller than the outer diameter of the solid sponge tire, and the elasticity of rubber is used to create a solid sponge. It is generally fitted snugly on the tire. However, in this case, the rubber tube tends to be stretched, the original softness is lost, and the grip force tends to be reduced. To prevent the decrease in grip force due to the elongation of the rubber tube, the inner diameter of the rubber tube may be made slightly smaller than or substantially the same as the outer diameter of the solid sponge tire. The rubber tube is easily disengaged from the sponge tire due to the force applied when decelerating or turning a curve. To prevent this, the sponge tire and the rubber tube are bonded, but it is difficult to apply the adhesive evenly, and the difference in the thickness of the applied adhesive appears on the surface of the rubber tube, and the tire outer peripheral surface is even. However, fine irregularities are generated, which causes a decrease in grip strength. The influence of the difference in the thickness of the adhesive on the finish of the outer peripheral surface of the tire becomes greater as the rubber tube made of a softer material becomes larger, and as a result, there is a limit to softening the material of the rubber tube in order to increase the grip.
Further, both ends of the rubber tube are likely to be lifted up on the side surface of the sponge tire, which makes the appearance unsightly and also causes vibration due to imbalance when considering that the tire rotates at high speed.

Therefore, it is an object of the present invention to solve the above-mentioned drawbacks of the conventional tire for a toy car.

[0007]

In order to solve the above-mentioned problems, the present invention seeks a grip force by using a soft rubber material and a rigidity by using a hard sponge body. Introduce a technical concept.

Specifically, the present invention has an outer skin made of soft rubber and a sponge body which is foamed so as to be integrated with the outer skin on the inside of the outer skin, and the outer skin secures a grip force on a road surface. A toy car tire is provided in which the sponge body ensures the rigidity required for the tire.

Further, the present invention comprises molding a skin made of a rubber material, placing the skin in a mold with a core, and foam molding a sponge body between the inside of the skin and the core. A method of manufacturing a tire for a toy car is provided.

[0010]

In the present invention, the outer shape of the tire is formed of a soft rubber in the mold, and then the sponge body is filled in the tire,
Due to the foaming, the rubber that serves as the outer skin is less subject to a pulling force, the original flexibility is not impaired, and high gripping power is easily obtained. Further, since the rubber to be the skin and the sponge inside are fused together at the time of molding, it is not necessary to use an adhesive and the finish of the tire outer peripheral surface can be made uniform. Further, since the molding is performed in the mold, it is possible to enhance the authenticity by putting a tread pattern on the outer peripheral surface or putting characters on the side surface like a tire used in a real automobile. Furthermore, the skin made of a soft rubber material shows a sufficient grip force on various road surfaces, and the sponge body shows the rigidity required for the tire, so the skin does not consider the rigidity at all, and only the grip force is
In addition, the sponge body allows material selection without paying attention to gripping force, focusing only on rigidity.

[0011]

[Example] A tire 1 for a toy car has a skin 2 made of a soft rubber material.
And a sponge body 3 which is inside the epidermis and is integral with the epidermis
And the sponge body 3 is supported by the wheel 4.
The skin 2 has a thickness of 1.5 mm or less and can be made of a material such as natural rubber, styrene-butadiene rubber, butyl rubber, butadiene rubber, urethane rubber, or polynorbornene rubber, and is soft enough to enhance grip with the road surface. Say it. That is, the rigidity required for the tire is ignored, and the material is selected in consideration of only the grip force. The skin 2 may have a hardness of 40 ° or less according to the JIS-A type hardness meter. Preferably, the hardness meter has a range of 15 to 25 °. The sponge body 3 is preferably a material that can be molded into a foam, is lightweight, has sufficient rigidity to absorb vibrations and support the weight of the vehicle body. For example, a resin material such as urethane resin, vinyl chloride resin, polystyrene resin can be used. A sponge body with an ASKER-C hardness meter of 30 ° or less may be used. Preferably, the hardness meter has a range of 15 to 25 °.

Next, a molding example of the toy car tire 1 will be shown.
A natural rubber was applied at 160 ° C. for 10 minutes with a mold for forming the outer peripheral surface of the tire having a thickness of 1 mm and its edge, and the skin 2 was produced.
This skin 2 is placed in the mold 5 shown in the figure, and on its inner peripheral surface,
Vinyltrimethoxysilane (Shin-Etsu Chemical, KBU-100
3) Apply 2% by weight diluted product. From the periphery of the core, an ether type urethane resin (Nippon Polyurethane Industry, a mixture of CFA-001 and NFA-001) is poured into the mold 5 and allowed to cure for 30 minutes at room temperature while foaming 5 times.
A tire 1 in which the skin 2 and the sponge body 3 were integrated was produced.

The running test results of the sponge core rubber tire thus formed are shown below. Tire characteristics Shape: Front wheel φ55mm Rear wheel φ58mm Material: Rubber skin 2 Natural rubber Hardness 20 ° (JIS-A type hardness tester) Inner sponge 3 Urethane resin hardness 20 ° (ASKER-C type hardness tester) Integrated product hardness 30 ° ( ASKER-C type hardness tester) Rubber skin thickness: 1mm Weight: Front wheel 12.5g Rear wheel 15.2g Result A soft grip feel and bend with neutral steering like light four-wheel steering around the body, at this time The steering angle of the car was small and there was no stall due to twisting the front wheels, and it showed high speed and high efficiency cornering that greatly contributes to shortening the lap time. For comparison, a conventional hollow rubber tire, a solid sponge tire, and a capped tire of the same size were placed in the same vehicle body and run under the same conditions, but the lap time was shorter than that of the sponge core rubber tire.

[0014]

The tire for a toy car according to the present invention can be finished as light as a solid sponge tire by selecting the material of the sponge body and the expansion ratio. Further, the edge of the skin can be made integral with the sponge body so that it has the same shape as the actual tire, giving a sense of scale.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example of a tire of the present invention.

FIG. 2 is a cross-sectional view showing a tire molding example.

[Explanation of symbols]

 1 Tire 2 Skin 3 Sponge 4 Wheel

Claims (3)

[Claims] 1. An outer skin made of soft rubber and a sponge body which is foamed so as to be integrated with the outer skin on the inner side of the outer skin. The outer skin secures a grip force on a road surface, and the sponge body is used for a tire. Toy car tires that ensure the required rigidity. 2. The toy vehicle tire according to claim 1, wherein the outer skin is made of natural rubber and the sponge body is made of a synthetic resin material. 3. Molding a skin made of a rubber material,
A method for manufacturing a tire for a toy car, comprising placing a skin in a mold with a core, and foaming a resin material between the inside of the skin and the core to form a sponge body.