Patent ID: 7175102
Filing Date: 2007-02-13
Classification: G01K,G05D

Abstract:
1. A thermal element comprising: a case having a thermally expandable body capable of expanding as a temperature rises and contracting as the temperature decreases inside the case; a piston which moves forward and backward following the expansion and contraction of the thermally expandable body and which is disposed inside said case along an axial line of said case, said piston having an inward end in said thermally expandable body, and an outward end protruding to the outside from one end of the case; a guide member disposed at least partially inside said case and slidably holding said piston; and a sealing member disposed adjacent to the guide member inside said case and sealing said thermally expandable body inside the case, wherein said case is formed as a hollow container having a shape of a substantially closed-end tube that has an opening for fitting said guide member and has a closed-end portion with an inner peripheral surface of a spherical shape formed in an end portion on an opposite side of the opening, said guide member has a through hole on the axial line and an outer peripheral portion thereof is molded from a resin to imitate an inner peripheral shape of said case, said sealing member is inserted and provided between said guide member and said thermally expandable body inside said case, and said thermally expandable body is obtained by mixing a wax and a thermoplastic elastomer and then gelling by admixing a copper powder.