Patent ID: 7441632
Filing Date: 2008-10-28
Classification: B60T,F16D,G01L

Abstract:
1. A force sensor comprising: a first member to which a magnet is fixed; a second member to which an electrical element is fixed, the electrical element outputting an output voltage that varies in accordance with relative displacement of the electrical element with respect to the magnet; a main coil spring interposed between the first member and the second member and elastically deforming in accordance with force produced between the first member and the second member along a direction of reciprocation of the first member with respect to the second member; and a sub coil spring, which is disposed within the main coil spring, for imparting a preload such that, in a state in which the amount of elastic deformation of the main coil spring is substantially zero, no clearance along the direction of reciprocation is formed between the first member and one end portion of the main coil spring and no clearance along the direction of reciprocation is formed between the second member and the other end portion of the main coil spring; the main coil spring and sub coil spring are arranged such that as the amount of elastic deformation of the main coil spring increases, the amount of elastic deformation of the sub coil spring decreases.