Electric power steering device

Patent metadata

Field	Value
Publication number	US-2016137220-A1
Application number	US-201314442144-A
Country	US
Kind code	A1
Filing date	Sep 20, 2013
Priority date	Nov 19, 2012
Publication date	May 19, 2016
Grant date	—

Abstract

A column-assist type electric power steering device ( 10 ) is provided with: a steering shaft ( 22 ); a magnetostrictive type torque sensor ( 80 ) that detects a torque produced in the steering shaft ( 22 ); and bearings ( 64, 65 ) that rotatably support the steering shaft ( 22 ). The magnetostrictive type torque sensor ( 80 ) includes a magnetostrictive film ( 81 ) disposed on an outer peripheral surface of the steering shaft ( 22 ), and a detection unit ( 83 ) that is disposed opposite the magnetostrictive film ( 81 ) and that detects a change in permeability. The bearings ( 64, 65 ) are installed at two locations in the axial direction of the steering shaft ( 22 ) in such a manner as to sandwich the detection unit ( 83 ).

First claim

1 . An electric power steering apparatus comprising: a magnetostrictive torque sensor that detects torque produced in a steering shaft; bearings that rotatably support the steering shaft; and a steering wheel provided on one end of the steering shaft,
characterized in that the magnetostrictive torque sensor includes a magnetostrictive film provided on an outer circumferential surface of the steering shaft, and a detection section provided in opposed relation to the magnetostrictive film for detecting variation in magnetic permeability, and in that the bearings are provided on two axially-spaced portions of the steering shaft in such a manner that the detection section is disposed between the bearings.

2 . The electric power steering apparatus according to claim 1 , wherein a rotational torque detection device is constituted by the magnetostrictive torque sensor that detects intensity and direction of rotational torque acting on the steering shaft as a driver rotates the steering wheel, and
which further comprises an assisting torque motor that generates assisting torque, the assisting torque motor generating assisting torque corresponding to a result of detection by the rotational torque detection device and imparting the generated assisting torque to the steering shaft.

3 . The electric power steering apparatus according to claim 1 or 2 , wherein at least one of the bearings provided on the two axially-spaced portions comprises a double-row roller bearing.

4 . The electric power steering apparatus according to claim or 2 , wherein at least one of the bearings provided on the two axially-spaced portions comprises a plurality of single-row roller bearings provided in succession along the steering shaft.

Assignees

• Honda Motor Co Ltd

Inventors

• Shiraishi Takehito
• Shimizu Yasuo

Classifications

• B62D5/0463 Primary

  calculating assisting torque from the motor based on driver input · CPC title

• B62D6/10 Primary

  characterised by means for sensing {or determining} torque · CPC title

• G01L3/102

  involving magnetostrictive means (magnetostrictive sensors H10N35/101) · CPC title

• G01L5/221

  to steering wheels, e.g. for power assisted steering · CPC title