1. Field of the Invention
The present invention relates to a tire, and more particularly to a tire having self-sealing property.
2. Description of the Prior Art
Conventional self-sealing tires have sealing gel coated on their inner tire surfaces. As the tire is punctured, the sealing gel can fill the hole to prohibit the tire from deflation.
Some self-sealing tires have sealant chambers to receive the sealing gel therein, as disclosed in U.S. Pat. No. 7,316,253. The inner tire surface is formed with the sealant chamber prior to the filling of the sealing gel. However, the forming process of the sealant chamber and the filling of the sealing gel are both complicated. Thus such tire having sealant chamber is hard to be produced.
Other self-sealing tires have their inner tire surfaces directly coated with the sealing gel, as disclosed in U.S. Pat. No. 4,359,078. Nevertheless, the balance loss of the tire is commonly seen when the tire rotates quickly, manly because the centrifugal force and the high temperature environment cause the sealing gel to ununiformly distribute over the inner tire surface. What's worse, the sealing gel might delaminate from the inner tire surface, which seriously affects the driving safety.
The present invention is, therefore, arisen to obviate or at least mitigate the above mentioned disadvantages.
The main object of the present invention is to provide a self-sealing tire having a composite structure to prohibit the tire from the risk of sealing gel concentration or delamination.
To achieve the above and other objects, the tire of the present invention has an inner tire surface, which is formed with a plurality of protrusions. The protrusions are circumferentially distributed over the inner tire surface. A sealing gel layer is disposed on the inner tire surface and at least partially covers the protrusions to form a composite structure.
Thereby, the protrusions can spread the force applied on the sealing gel layer while the tire is rotated rapidly. As such, the problems that the sealing gel layer is concentrated or delaminated can be prohibited.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment(s) in accordance with the present invention.
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The sealing gel layer 20 is substantially unflowable and has high viscosity, and the sealing gel layer 20 can endure 120 degree Celsius without being melted. As the tire is punctured by an object, the sealing gel will stick onto the object, and the sealing gel can be further pulled in correspondence to the movement of the object, so as to further fill in the hole through which the object punctures. As such, the tire of the present invention has self-sealing property to prevent deflation while punctured.
In order to reduce the weight of the tire, the sealing gel layer 20 may be a foaming layer, and the foaming layer has a plurality of close-celled bubbles. As a result, the sealing gel layer 20 can be light-weighted, and the close-celled bubbles, rather than open-celled bubbles, can still ensure the self-sealing property of the tire.
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In a preferred embodiment of the present embodiment, the sealing gel layer 20 is made of polyurethane, and the materials thereof include diisocyanate and polyol. The materials are still flowable in the blending device 30. Once the materials are coated on the inner tire surface 10, the diisocyanate and the polyol are gradually reacted to generate the polyurethane until the materials are spread within a width of the inner tire surface uniformly and become unflowable to form the sealing gel layer 20. The materials can be further blended with air, such as nitrogen, or foaming agent in the blending device 30 in order to form a foaming layer on the inner tire surface 10.
The protrusions on the inner tire surface not merely increase the contact area which contacts the sealing gel layer, but also forms a composite structure with the sealing gel layer. As such, the protrusions can spread the force applied on the sealing gel layer when the tire rotates rapidly, so as to prevent the sealing gel layer from mass concentration or delamination. Therefore, the safety performance of the tire of the present invention can be significantly elevated.