Patent ID: 8473188

Claim:
A collision detecting system of a vehicle collision protection system comprising: a bumper reinforcement member, a crush box disposed between the bumper reinforcement member and a fixing member of the vehicle, a strain inducing member fixed to the crush box so as to distort in a longitudinal direction of the vehicle as the crush box is compressed between the reinforcement member and the fixing member, and a strain measuring element fixed to the strain inducing member, wherein: the strain inducing member has a strain measuring portion having such a shape that stress of the strain inducing member concentrates into the strain measuring portion; the strain measuring element is fixed to the strain measuring portion to measure a component of the strain of the strain measuring portion in the longitudinal direction of the vehicle; the strain measuring portion has an asymmetrical cross-section in a vertical direction of the vehicle such that outer and inner surfaces of the strain measuring portion are asymmetrical; the inner surface is opposite to the outer surface and faces the crush box; one of the outer and inner surfaces of the strain measuring portion is a flat surface and the other of the outer and inner surfaces of the strain measuring portion is a curved surface; the curved surface is curved toward the flat surface; and the asymmetrical cross-section is taken along a plane perpendicular to the longitudinal direction of the vehicle.