Magnetostrictive torque sensor and electric power steering apparatus including the same

• US 20070251333A1
• Filed: 04/05/2007
• Published: 11/01/2007
• Est. Priority Date: 04/14/2006
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Shimizu, Yasuo, Watanabe, Katsuji
• Granted Patent: US 7,806,005 B2
• Time in Patent Office: Days
• US Class Current: 73/862.333
• CPC Class Codes: B62D 6/10 characterised by means for sensing or determining torque
• CPC Class Codes: G01L 5/221 to steering wheels, e.g. for power assisted steering

Abstract

This magnetostrictive torque sensor includes: a shaft made of a magnetized material; a magnetostrictive portion provided on the shaft at a position distanced for a predetermined length from an end of the shaft; a detection coil that is arranged so as to face the magnetostrictive portion, and detects a change in a magnetic characteristic of the magnetostrictive portion; and a plating made of an nonmagnetic material, that is provided on the end of the shaft.

Claims

1. A magnetostrictive torque sensor comprising:

a shaft made of a magnetized material;

a magnetostrictive portion provided on the shaft at a position distanced for a predetermined length from an end of the shaft;

a detection coil that is arranged so as to face the magnetostrictive portion, and detects a change in a magnetic characteristic of the magnetostrictive portion; and

a plating made of an nonmagnetic material, that is provided on the end of the shaft.

2. An electric power steering apparatus which detects a steering input by a driver, and drives a motor in response to the detected steering input to steer a vehicle, the electric power steering apparatus comprising:

the magnetostrictive torque sensor according to claim 1, that detects the steering input; and

a reduction mechanism that is unitarily provided on another end of the shaft in order to transfer a torque generated by the driver or by the motor.