Relative angle detection device, torque sensor, electric power steering device and vehicle

Patent metadata

Field	Value
Publication number	US-10035535-B2
Application number	US-201615578064-A
Country	US
Kind code	B2
Filing date	Jun 24, 2016
Priority date	Jun 26, 2015
Publication date	Jul 31, 2018
Grant date	Jul 31, 2018

Abstract

There are provided a relative angle detection device suitable for expanding a torque detection range, and a torque sensor, an electric power steering device and a vehicle including the relative angle detection device. Based on a first sine signal representing sin(θos+Δθ) and a first cosine signal representing cos(θos+Δθ) in accordance with a rotation angle(θis) of a first multipolar ring magnet that synchronously rotates with an input shaft from between the coaxially arranged input shaft and an output shaft, and based on a second sine signal representing sin θos and a second cosine signal representing cos θos in accordance with a rotation angle(θos) of a second multipolar ring magnet that synchronously rotates with the output shaft, sin Δθ and cos Δθ are calculated in accordance with a relative angle(Δθ) between the input shaft and the output shaft, and from Δθ=arctan(sin Δθ/cos Δθ), the relative angle(Δθ) is calculated.

First claim

The invention claimed is:

1. A relative angle detection device comprising:
a first multipolar ring magnet having different magnetic poles alternately and equally distributed in a circumferential direction and configured to synchronously rotate with a first rotation axis from between the coaxially arranged first rotation axis and a second rotation axis;
a second multipolar ring magnet having different magnetic poles alternately and equally distributed in a circumferential direction and configured to synchronously rotate with the second rotation axis from between the first rotation axis and the second rotation axis;
a first rotation angle sensor configured to detect a magnetic flux in accordance with a rotation angle θ 1 of the first multipolar ring magnet and output a first sin signal representing sin θ 1 and a first cos signal representing cos θ 1 ;
a second rotation angle sensor configured to detect a magnetic flux in accordance with a rotation angle θ 2 of the second multipolar ring magnet and output a second sin signal representing sin θ 2 and a second cos signal representing cos θ 2 ;
a plurality of relative angle calculation units configured to, based on the first sin signal, the first cos signal, the second sin signal and the second cos signal, calculate a relative angle Δθ between the first rotation axis and the second rotation axis; and wherein
the plurality of relative angle calculation units include:
one or more first relative angle calculation unit configured to, based on the first sin signal and the first cos signal, calculate the rotation angle θ 1 , based on the second sin signal and the second cos signal, calculate the rotation angle θ 2 , and based on a difference value between the rotation angle θ 1 and the rotation angle θ 2 , calculate a first relative angle Δθ1 between the first rotation axis and the second rotation axis; and
one or more second relative angle calculation unit configured to, based on the first sin signal, the first cos signal, the second sin signal and the second cos signal, calculate sin Δθ and cos Δθ in accordance with a relative angle Δθ between the first rotation axis and the second rotation axis, and from Δθ2=arctan(sin Δθ/cos Δθ), calculate a second relative angle Δθ2 between the first rotation axis and the second rotation axis;
the relative angle detection device comprising:
an abnormality determination unit configured to determine an abnormality based on a difference value between a third relative angle Δθref which is either one of the first relative angle Δθ1 calculated by the first relative angle calculation unit and the second relative angle Δθ2 calculated by the second relative angle calculation unit and a remaining relative angle from between the first relative angle Δθ1 and the second relative angle Δθ2.

2. The relative angle detection device according to claim 1 , wherein
the first multipolar ring magnet and the second multipolar ring magnet are configured such that a part of a circumference surface is magnetized to alternately different magnetic poles in a circumferential direction;
the first rotation angle sensor is provided such that a detection unit of a magnetic flux of the first rotation angle sensor faces a pole face formed to a circumference surface of the first multipolar ring magnet; and
the second rotation angle sensor is provided such that a detection unit of a magnetic flux of the second rotation angle sensor faces a pole face formed to a circumference surface of the second multipolar ring magnet.

3. The relative angle detection device according to claim 1 , wherein
the first multipolar ring magnet and the second multipolar ring magnet are configured such that a part of an axial end face is magnetized to alternately different magnetic poles in a circumferential direction;
the first rotation angle sensor is provided such that a detection unit of a magnetic flux of the first rotation angle sensor faces a pole face formed to the axial end face of the first multipolar ring magnet; and
the second rotation angle sensor is provided such that a detection unit of a magnetic flux of the second rotation angle sensor faces a pole face formed to the axial end face of the second multipolar ring magnet.

4. The relative angle detection device according to claim 1 , wherein
the first rotation angle sensor includes a first sin magnetic sensor configured to output the first sin signal and a first cos magnetic sensor configured to output the first cos signal, both provided to a pitch of a magnetic pole of the first multipolar ring magnet while having a phase difference of 90° of an electrical angle; and
the second rotation angle sensor includes a second sin magnetic sensor configured to output the second sin signal and a second cos magnetic sensor configured to output the second cos signal, both provided to a pitch of a magnetic pole of the second multipolar ring magnet while having a phase difference of 90° of an electrical angle.

5. A relative angle detection device comprising:
a first rotor having an outer circumference provided with a plurality of teeth at regular intervals and configured to synchronously rotate with a first rotation axis from between the coaxially arranged first rotation axis and a second rotation axis;
a second rotor having different magnetic poles alternately and equally distributed in a circumferential direction and configured to synchronously rotate with the second rotation axis from between the first rotation axis and the second rotation axis;
a first stator concentrically arranged with the first rotor at an outside of the first rotor, having a plurality of poles equally distributed in an inner circumference, and including an armature winding obtained by winding a coil around each pole;
a second stator concentrically arranged with the second rotor at an outside of the second rotor, having a plurality of poles equally distributed in an inner circumference, and including an armature winding obtained by winding a coil around each pole;
an excitation signal supply unit configured to supply, to the coil, an excitation signal; and
a plurality of relative angle calculation units configured to calculate a relative angle Δθ between the first rotation axis and the second rotation axis based on a first sin signal representing sin θ 1 and a first cos signal representing cos θ 1 in accordance with a rotation angle θ 1 of the first rotor output from the coil of the first stator supplied with the excitation signal and a second sin signal representing sin θ 2 and a second cos signal representing cos θ 2 in accordance with a rotation angle θ 2 of the second rotor output from the coil of the second stator supplied with the excitation signal and is; and wherein
the plurality of relative angle calculation units include:
one or more first relative angle calculation unit configured to, based on the first sin signal and the first cos signal, calculate the rotation angle θ 1 , based on the second sin signal and the second cos signal, calculate the rotation angle θ 2 , and based on a difference value between the rotation angle θ 1 and the rotation angle θ 2 , calculate a first relative angle Δθ1 between the first rotation axis and the second rotation axis; and
one or more second relative angle calculation unit configured to, based on the first sin signal, the first cos signal, the second sin signal and the second cos signal, calculate sin Δθ and cos Δθ in accordance with a relative angle Δθ between the first rotation axis and the second rotation axis, and from Δθ2=arctan(sin Δθ/cos Δθ), calculate a second relative angle Δθ2 between the first rotation axis and the second rotation axis;
the relative angle detection device comprising:
an abnormality determination unit configured to determine an abnormality based on a difference value betwe

Assignees

• Nsk Ltd

Inventors

• Ohira Kazuhiro
• Kuwahara Masaki
• Sugita Sumio
• Uematsu Shigeyuki

Classifications

• B62D5/0406 Primary

  including housing for electronic control unit · CPC title

• G01B7/30

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

• G01D5/244

  influencing characteristics of pulses or pulse trains; generating pulses or pulse trains · CPC title

• B62D15/02

  Steering position indicators {; Steering position determination; Steering aids} · CPC title

• G01L3/10

  involving electric or magnetic means for indicating · CPC title