Torque sensor and robot
Provided is a torque sensor that includes: a bearing that is provided with an inner ring and an outer ring that are supported so as to be relatively movable only in the direction of rotation about a predetermined axis; a connecting member that is provided with fixing sections that are respectively fixed to the inner ring and the outer ring and a strain generation section that connects between the fixing sections; and a strain sensor that is disposed on the connecting member so as to be capable of detecting a strain at least in the circumferential direction.
1. A torque sensor comprising:
a bearing that is provided with an inner ring and an outer ring that are supported so as to be relatively movable only in the direction of rotation about a predetermined axis;
a connecting member that is provided with fixing sections that are fixed on respective side surfaces of the inner ring and the outer ring and a strain generation section that connects between the fixing sections, the respective side surfaces being substantially perpendicular to the predetermined axis; and
a strain sensor that is disposed on the connecting member so as to be capable of detecting a strain at least in the circumferential direction.
2. The torque sensor according to claim 1 , wherein the transverse-sectional area of the strain generation section is smaller than the transverse-sectional areas of the fixing sections.
3. The torque sensor according to claim 1 , wherein the inner ring and the outer ring are provided with fixing means that fix the inner ring and the outer ring to a detection target.
4. The torque sensor according to claim 1 , wherein the connecting member is formed in a plate-like shape extending along the respective side surfaces.
5. The torque sensor according to claim 1 , wherein the strain sensor is provided with a correction means that corrects a strain-amount variation caused by an ambient-temperature change.
6. The torque sensor according to claim 1 , wherein the strain sensor is fixed to the connecting member with screws.
7. The torque sensor according to claim 1 , wherein a plurality of strain sensors that are each the same as the strain sensor are disposed side by side on the strain generation section.
8. The torque sensor according to claim 1 , wherein the bearing is a cross roller bearing.
9. The torque sensor according to claim 1 , wherein the bearing is a compound ball bearing.
10. The torque sensor according to claim 1 , wherein the bearing is a sliding bearing.
11. The torque sensor according to claim 1 , wherein:
a plurality of connecting members that are each the same as the connecting member are provided at intervals in the circumferential direction around the axis; and
the strain sensor is disposed on the strain generation section of each of the connecting members.
12. The torque sensor according to claim 1 , comprising at least one reinforcing member that is fixed to each of the inner ring and the outer ring and that couples the inner ring and the outer ring.
13. A robot to which a torque sensor according to claim 1 is attached while making the axis of the bearing match with the rotation axis of each joint.