Torque sensor, robot, and torque calculation method

Patent metadata

Field	Value
Publication number	US-11898922-B2
Application number	US-202217720098-A
Country	US
Kind code	B2
Filing date	Apr 13, 2022
Priority date	Oct 24, 2019
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

A torque sensor includes: a strain body; and an optical sensor configured to detect a deformation of the strain body. The strain body includes an outer peripheral portion having a ring shape, and an inner peripheral portion of which at least a part is disposed inside the outer peripheral portion in a radial direction. The optical sensor includes a scale fixed to one of the outer peripheral portion and the inner peripheral portion, and disposed between the outer peripheral portion and the inner peripheral portion, and a detector fixed to a remaining one of the outer peripheral portion and the inner peripheral portion, and disposed to face the scale between the outer peripheral portion and the inner peripheral portion.

First claim

What is claimed is:

1. A torque sensor comprising:
a strain body; and
an optical sensor configured to detect a deformation of the strain body,
wherein the strain body includes
an outer peripheral body having a ring shape, and
an inner peripheral body of which at least a part is disposed inside the outer peripheral body in a radial direction, and

the optical sensor includes
a scale fixed to one of the outer peripheral body and the inner peripheral body, and disposed between the outer peripheral body and the inner peripheral body, and
a detector fixed to a remaining one of the outer peripheral body and the inner peripheral body, and disposed to face the scale between the outer peripheral body and the inner peripheral body, and
wherein a substrate of the torque sensor is disposed in a space formed between the outer peripheral body and the inner peripheral body, and is provided with the detector.

2. The torque sensor according to claim 1 , wherein the strain body includes
a plurality of connectors disposed between the outer peripheral body and the inner peripheral body, and configured to connect the outer peripheral body and the inner peripheral body to each other, and
the substrate is arranged in the space among the plurality of connectors in a circumferential direction.

3. The torque sensor according to claim 2 , wherein a plurality of substrates is provided in a plurality of spaces among the plurality of connectors in the circumferential direction, respectively,
the torque sensor further comprises:
a coupler configured to electrically connect the substrates adjacent to each other in the circumferential direction, across each of the connectors.

4. The torque sensor according to claim 1 , wherein
a plurality of optical sensors is arranged at a plurality of positions of the strain body in the circumferential direction, and
the torque sensor further comprises:
a torque calculator configured to calculate a torque based on outputs of the plurality of optical sensors.

5. The torque sensor according to claim 4 , wherein
among the plurality of optical sensors, two optical sensors are arranged at a predetermined angular interval other than 90° in the circumferential direction, and
the torque calculator calculates the torque based on outputs of the two optical sensors.

6. The torque sensor according to claim 4 , wherein
among the plurality of optical sensors, two optical sensors are arranged at a predetermined angular interval other than 180° in the circumferential direction, and
the torque calculator calculates the torque based on outputs of the two optical sensors.

7. The torque sensor according to claim 4 , wherein four optical sensors are arranged in intervals of 90° in the circumferential direction.

8. The torque sensor according to claim 4 , wherein three optical sensors are arranged at intervals of 120° in the circumferential direction.

9. The torque sensor according to claim 4 , wherein the torque calculator adds outputs of the plurality of optical sensors, and calculates the torque based on a result of the addition.

10. The torque sensor according to claim 1 , wherein
the outer peripheral body includes a protrusion that protrudes from an end of the inner peripheral body in an axial direction toward one side of the axial direction, and
the torque sensor further comprises:
a first seal disposed between the protrusion and a functional operator to which the outer peripheral body or the inner peripheral body is fixed.

11. The torque sensor according to claim 1 , further comprising:
a second seal disposed between the inner peripheral body and a functional operator to which the outer peripheral body or the inner peripheral body is fixed.

12. The torque sensor according to claim 1 , wherein the inner peripheral body also serves as an internal gear of a speed reducer to which the inner peripheral body is fixed.

13. The torque sensor according to claim 1 , wherein
the strain body includes a plurality of substrate fixing boards fixed to the remaining one of the outer peripheral body and the inner peripheral body, protruding between the outer peripheral body and the inner peripheral body, and configured to fix each substrate having the detector at a plurality of fixing positions, and
the detector is disposed at an intermediate position between the plurality of fixing positions on each substrate.

14. The torque sensor according to claim 13 , further comprising:
a pin inserted through a first pin hole formed in the substrate and press-fitted into a second pin hole formed in each of the substrate fixing boards.

15. The torque sensor according to claim 14 , wherein the first pin hole is formed to be larger than a diameter of the pin, and an adhesive is filled in a gap between the pin and the first pin hole.

16. The torque sensor according to claim 1 , further comprising:
a mounting piece separate from the outer peripheral body and the inner peripheral body, configured to be detachable from the outer peripheral body or the inner peripheral body, and configured to fix the detector or the scale thereto.

17. The torque sensor according to claim 1 , wherein
the strain body includes a plurality of connectors arranged between the outer peripheral body and the inner peripheral body, and configured to connect the outer peripheral body and the inner peripheral body to each other, and
in the outer peripheral body, positions of fastening to a functional operator to which the outer peripheral body is fixed are arranged to be denser at positions that correspond to the connectors in the circumferential direction, than those at positions that do not correspond to the connectors.

18. A robot comprising the torque sensor according to claim 1 at a tip of an arm.

19. A robot comprising a torque sensor at a tip of an arm, wherein
the torque sensor includes
a strain body, and
a sensor configured to detect a deformation of the strain body,

the strain body includes
an outer peripheral body having a ring shape,
an inner peripheral body of which at least a part is disposed inside the outer peripheral body in a radial direction, and
a protrusion provided in the outer peripheral body, and protruding from an end of the inner peripheral body in an axial direction toward one side of the axial direction, and the torque sensor further includes
a seal disposed between the protrusion and a functional operator to which the outer peripheral body or the inner peripheral body is fixed, the functional operator including a slide bearing that is provided with an outer ring, and an inner ring rotatable with respect to the outer ring along with a sliding body disposed between the inner ring and the outer ring.

20. A torque calculation method comprising:
providing a torque sensor including
a strain body, and
a plurality of optical sensors arranged at a plurality of positions of the strain body in a circumferential direction, and configured to detect a deformation of the strain body,
wherein the strain body includes
an outer peripheral body having a ring shape, and
an inner peripheral body of which at least a part is disposed inside the outer peripheral body in a radial direction, and

wherein each of the plurality of optical sensors includes
a scale fixed to one of the outer peripheral body and the inner peripheral body, and disposed between the outer peripheral body and the inner peripheral body, and
a detector fixed to a remaining one of the outer peripheral body and the inner peripheral body, and

Assignees

• Yaskawa Electric Corp

Inventors

• Zhao Fei
• Toma Kumiko
• Soga Takehito
• Sadakane Kenichi
• Yoshida Yasushi

Classifications

• G01L3/08 Primary

  involving optical means for indicating · CPC title

• B25J13/085 Primary

  Force or torque sensors (B25J13/082, B25J13/084 take precedence) · CPC title

• G01L5/0028

  Force sensors associated with force applying means (G01L5/0052, G01L5/0057, G01L5/0061 take precedence) · CPC title

• G01L3/14

  wherein the torque-transmitting element is other than a torsionally-flexible shaft · CPC title