| 摘要 |
PURPOSE:To prevent the wear of a spike and a road surface and noise by imbedding in a tire, a spike pin that is energized by a spring in the protruding direction and is energized and retained by spring made of shape memory alloy in the receding direction so as to protrude at low temperature and to recede at high temperature. CONSTITUTION:The force of a spring 4 made of shape memory alloy is so set that it exceeds the force of a spring 5 when the ambient temperature is higher than the allowable memory temperature of said spring 4 made of shape memory alloy. Consequently, under this temperature condition, that is, when there is no ice and snow and a spike tire need not be used, a collet 3 is tightened by the force of the spring 4 made of shape memory alloy and a pin 2 pushed in by touching a road surface is retained in the receding state. However, if an icebound road surface occurs and the tire temperature is decreased, the force of the spring 4 made of shape memory alloy is reduced and the collet 3 is loosened by the force of the spring 5. Then, the pin 2 is protruded by a spring 1 and the tire functions as the spike tire. As a result of this structure, the damage of the road surface, the wear of the pin, and noise can be prevented.
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