Magnet structure, rotational angle detector, and electric power steering device

Patent metadata

Field	Value
Publication number	US-2019280568-A1
Application number	US-201816185263-A
Country	US
Kind code	A1
Filing date	Nov 9, 2018
Priority date	Mar 8, 2018
Publication date	Sep 12, 2019
Grant date	—

Abstract

A magnet structure is a magnet structure for a TMR element which is an MR element. The magnet structure includes a bonded magnet compact that has a first main surface facing the TMR element, and a second main surface on a side opposite to the first main surface; and a tubular member that supports the bonded magnet compact. The bonded magnet compact has a gate portion which is provided on the second main surface and includes a gate mark formed by performing injection molding. The gate portion is provided at a position overlapping a center on the second main surface when seen from the second main surface side.

First claim

What is claimed is:

1 . A magnet structure for a magnetoresistance effect element, comprising:
a magnet compact that has a first main surface facing the magnetoresistance effect element, and a second main surface on a side opposite to the first main surface; and a support portion that supports the magnet compact, wherein the magnet compact has a gate portion which is provided on the second main surface and includes a gate mark formed by performing injection molding, and the gate portion is provided at a position overlapping a center on the second main surface when seen from the second main surface side.

2 . The magnet structure according to claim 1 ,
wherein the support portion is a tubular member which supports a side surface of the magnet compact on one end side, the first main surface of the magnet compact is disposed on the one end side of the support portion, and the second main surface is disposed to be closer to the one end side than the other end on the other end side opposite to the one end side of the support portion.

3 . The magnet structure according to claim 1 ,
wherein the support portion is a tubular shaft which has a smaller outer diameter than the magnet compact, is attached to the second main surface side, and extends in a direction intersecting the second main surface, and the gate portion is positioned on an inner side of the shaft when seen from the second main surface side.

4 . A rotational angle detector comprising:
the magnet structure according to claim 1 ; and a magnetoresistance effect element that is disposed to face the first main surface of the magnet structure.

5 . The rotational angle detector according to claim 4 ,
wherein a magnetoresistance ratio of the magnetoresistance effect element is 90% or higher.

6 . The rotational angle detector according to claim 4 ,
wherein the magnetoresistance effect element is a tunnel magnetoresistance effect element.

7 . An electric power steering device comprising:
the rotational angle detector according to claim 4 .

Assignees

• Tdk Corp

Inventors

• Mori Naoki
• Okada Yoshiaki

Classifications

• G01B7/30

  for measuring angles or tapers; for testing the alignment of axes · CPC title

• G01D5/145

  influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06) · CPC title

• H01F7/0294

  Detection, inspection, magnetic treatment · CPC title

• H01F10/3254

  the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ] · CPC title

• B62D5/0481

  monitoring the steering system, e.g. failures · CPC title