Torque Detection Device and Electric Power Steering System

Patent metadata

Field	Value
Publication number	US-2018029634-A1
Application number	US-201715653946-A
Country	US
Kind code	A1
Filing date	Jul 19, 2017
Priority date	Jul 27, 2016
Publication date	Feb 1, 2018
Grant date	—

Abstract

A torque detection device capable of suppressing intrusion of static electricity thereinto. A magnetism collection unit includes magnetism collection rings, first and second magnetism collection holders that hold the magnetism collection rings, respectively, and a magnetic shield that covers the outer peripheries of the magnetism collection rings. The inner peripheral surface of the first magnetism collection holder is provided wife recessed portions. The outer peripheral surface of the second magnetism collection holder is provided with engagement protrusions to be inserted into the recessed portions. The inner peripheral surface of the second magnetism collection holder is provided with recessed portions. The inner peripheral surface of the first magnetism collection holder is provided with protrusions that project toward the second magnetism collection holder. The protrusions are inserted into the recessed portions when the first magnetism collection holder and the second magnetism collection holder are assembled to each other.

First claim

What is claimed is:

1 . A torque detection device comprising:
a permanent magnet; a magnetic yoke which is disposed in a magnetic field formed by the permanent magnet and a position of which relative to the permanent magnet is variable in accordance with a torsional angle of a torsion bar; a tubular magnetism collection unit that has a tubular magnetism collection holder, a magnetism collection ring, and a tubular magnetic shield, the magnetism collection holder being composed of a first magnetism collection holder and a second magnetism collection holder, which are disposed adjacent to each other in an axial direction and assembled to each other, to surround the magnetic yoke, the magnetism collection ring being attached to an inner peripheral surface of the magnetism collection holder to collect magnetic flux of the magnetic yoke, and the magnetic shield being fitted with an outer peripheral surface of the magnetism collection holder to be attached; and a magnetic sensor that detects magnetic flux from a magnetic circuit formed by the permanent magnet, the magnetic yoke, and the magnetism collection ring, wherein the first magnetism collection holder is provided with a first positioning recessed portion and a first protrusion, and the second magnetism collection holder is provided with a second protrusion and a second positioning recessed portion, the second protrusion being inserted into the first positioning recessed portion and the first protrusion being inserted into the second positioning recessed portion with the first magnetism collection holder and the second magnetism collection holder assembled to each other,

2 . The torque detection device according to claim 1 , wherein:
the first positioning recessed portion is provided at a position that is different from that of the second positioning recessed portion in a circumferential direction of the magnetism collection holder; and the first protrusion is provided at a position that is different from that of the second protrusion in the circumferential direction of the magnetism collection holder.

3 . The torque detection device according to claim 1 , wherein;
the first positioning recessed portion and the second positioning recessed portion are provided at the same position in a circumferential direction of the magnetism collection holder and at different positions in a radial direction of the magnetism collection holder; and the first protrusion and the second protrusion are provided at the same position in the circumferential direction of the magnetism collection holder and at different positions in the radial direction of the magnetism collection holder.

4 . The torque detection device according to claim 1 , wherein
at least one of the first protrusion and the second protrusion includes an engagement lug that is engaged with an end surface of the first magnetism collection holder or the second magnetism collection holder in a radial direction with the first protrusion and the second protrusion inserted into the first positioning recessed portion and the second positioning recessed portion.

5 . An electric power steering system comprising:
the torque detection device according to claim 1 .

Assignees

• Jtekt Corp

Inventors

• Toyama Yuichi

Classifications

• B62D15/0235

  by measuring or deriving directly at the electric power steering motor · CPC title

• G01L3/1435

  involving magnetic or electromagnetic means · CPC title

• B62D5/0463 Primary

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

• G01L3/104 Primary

  involving permanent magnets · CPC title

• B62D5/04

  electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear · CPC title