Torque measuring device

Patent metadata

Field	Value
Publication number	US-12306059-B2
Application number	US-202318175802-A
Country	US
Kind code	B2
Filing date	Feb 28, 2023
Priority date	Mar 1, 2022
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

A torque measuring device includes: a coil unit having a detection coil configured to change a voltage in response to a change in magnetic permeability of a magnetostrictive effect section of a rotating shaft; a back yoke arranged coaxially around the coil unit; a holder configured to hold the coil unit and the back yoke; and an electronic circuit including the detection coil and configured to generate an output voltage according to a voltage of the detection coil, a clearance in a radial direction is provided between an outer peripheral surface of the coil unit and an inner peripheral surface of the back yoke, and a range of change in the clearance that accompanies temperature change during use is regulated to a range in which a change in the output voltage is linear with respect to the change in the clearance.

First claim

The invention claimed is:

1. A torque measuring device, comprising:
a coil unit formed into a cylindrical shape as a whole and having a detection coil configured to change a voltage in response to a change in magnetic permeability of a magnetostrictive effect section of a rotating shaft, the magnetic permeability changing according to torque to be transmitted;
a back yoke formed in a cylindrical shape and arranged coaxially around the coil unit;
a holder configured to hold the coil unit and the back yoke; and
an electronic circuit including the detection coil and configured to generate an output voltage according to a voltage of the detection coil; wherein
a clearance in a radial direction is provided between an outer peripheral surface of the coil unit and an inner peripheral surface of the back yoke; and
a range of change in the clearance which accompanies temperature change during use is regulated to a range in which a change in the output voltage is linear with respect to the change in the clearance.

2. The torque measuring device according to claim 1 , wherein
a spacer is provided and sandwiched between the outer peripheral surface of the coil unit and the inner peripheral surface of the back yoke, and the clearance is formed by the spacer.

3. The torque measuring device according to claim 2 , wherein
the holder has a holder cylindrical portion, and the holder cylindrical portion forms the spacer;
the coil unit is fitted into the holder cylindrical portion; and
the back yoke is fitted onto the holder cylindrical portion.

4. The torque measuring device according to claim 3 , wherein
the holder has an inner protection portion positioned on an inner side in the radial direction of the coil unit; and
the holder includes an inward facing flange portion that protrudes inward in the radial direction from at least one of end portions on both sides in an axial direction of the holder cylindrical portion, the inward facing flange portion has an inner end portion in the radial direction positioned on the inner side in the radial direction of the inner peripheral surface of the coil unit, and the inner end portion in the radial direction of the inward facing flange portion forms the inner protection portion.

5. The torque measuring device according to claim 3 , wherein
the holder has an inner protection portion positioned on an inner side in the radial direction of the coil unit, and a holder cylindrical portion;
the coil unit is embedded in the holder cylindrical portion;
the back yoke is fitted onto the holder cylindrical portion;
a part of the holder cylindrical portion located between the outer peripheral surface of the coil unit and the inner peripheral surface of the back yoke forms the spacer; and
a portion of the holder cylindrical portion located on the inner side in the radial direction of the inner peripheral surface of the coil unit forms the inner protection portion.

6. The torque measuring device according to claim 2 , wherein
the holder has a holder cylindrical portion;
the back yoke is embedded in the holder cylindrical portion; and
a portion of the holder cylindrical portion located between the inner peripheral surface of the back yoke and the outer peripheral surface of the coil unit forms the spacer.

7. The torque measuring device according to claim 2 , wherein
the coil unit is configured by a flexible substrate; and
a band-shaped member fixed to the flexible substrate is sandwiched between the outer peripheral surface of the coil unit and the inner peripheral surface of the back yoke, and the band-shaped member forms the spacer.

8. The torque measuring device according to claim 7 , wherein
the holder has an inner protection portion positioned on an inner side in the radial direction of the coil unit;
the holder further has an inner cylindrical portion arranged on the inner side in the radial direction of the coil unit, and the inner cylindrical portion forms the inner protection portion.

9. The torque measuring device according to claim 1 , wherein the holder has an inner protection portion positioned on an inner side in the radial direction of the coil unit.

10. The torque measuring device according to claim 9 , wherein the holder has an inner cylindrical portion arranged on the inner side in the radial direction of the coil unit, and the inner cylindrical portion forms the inner protection portion.

11. The torque measuring device according to claim 1 , wherein the coil unit is configured by a flexible substrate.

Assignees

• Nsk Ltd
• Proterial Ltd

Inventors

• Kobayashi Masahiro
• Fukuda Kota
• FUKUI Hisayoshi
• Odera Takahiro
• Nakamura Teruyuki
• Futakuchi Naoki
• Okuyama Ken

Classifications

• G01L3/105

  involving inductive means (G01L3/102, G01L3/104 take precedence) · CPC title

• G01L5/136

  Force sensors associated with a vehicle traction coupling (vehicle connections B60D; control of vehicle brakes B60T) · CPC title

• G01L3/102 Primary

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