Patent ID: 7992692
Filing Date: 2011-08-09
Classification: F16F

Abstract:
1. A damper comprising: a cylinder which has a hollow portion therein; a piston rod which is inserted through an upper side of the cylinder and has a groove pattern having a plurality of convex portions and concave portions which are alternately formed; a piston valve which is connected with a lower end of the piston rod so as to be reciprocated in the cylinder and has a fluid passing hole which is formed in an up and down direction; a rod guide which closes up an upper end of the cylinder and guides an up-down movement of the piston rod and which has a through-hole at a side portion thereof; and a sensor module which is installed to the rod guide so as to detect a movement of the piston rod by using a variation in magnetic field generated when the piston rod is moved, wherein the sensor module comprises: a magnet for generating a magnetic field; a GMR sensor which is placed between the magnet and the piston rod so as to detect a variation in the magnetic field and then output an electric signal; a signal processing part for processing the output signal from the GMR sensor and outputting a square wave; and a housing for supporting the magnet, the GMR sensor and the signal processing part.