Patent ID: 8957670
Filing Date: 2015-02-17
Classification: G01B,G01D

Abstract:
1. A stroke amount detection device for detecting a position of a detection object that moves on a virtual straight line with respect to a holding part, comprising: a yoke attached to one of the detection object and the holding part, the yoke formed into a pipe shape from magnetic material, the yoke having a protruding device that protrudes to outside the yoke in a direction perpendicular to the virtual straight line, the protruding device having a top portion at which a distance from the virtual straight line in the direction perpendicular to the virtual straight line is maximum; a magnetic flux generation device attached to the other one of the detection object and the holding part, and located in the yoke; and a magnetism detection device disposed between the magnetic flux generation device and the protruding device, the magnetism detection device disposed at a fixed position with respect to the magnetic flux generation device, the magnetism detection device having a magnetism sensing direction in a direction perpendicular to a direction of a magnetic flux passing through the magnetic flux generation device, the magnetism detection device outputting a signal in accordance with a magnetic flux density generated due to a relative movement of the yoke with respect to the magnetism detection device.