Vibration actuator, and drive device, multi-axis stage unit, and articulated robot that use vibration actuator

Patent metadata

Field	Value
Publication number	US-11469688-B2
Application number	US-202016904694-A
Country	US
Kind code	B2
Filing date	Jun 18, 2020
Priority date	Jun 19, 2019
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

A vibration actuator capable of reducing variations of pressure force and reaction force acting on a vibrator and a contact member has a specific construction. Vibrator devices respectively have vibrators, each of which includes an elastic member and an electro-mechanical energy conversion element. A contact member contacts the vibrators and is movable in a predetermined direction relatively to the vibrators. A restraint member fixes a first vibrator device among the vibrator devices to restrict a degree of freedom in the predetermined direction. A flexible member connects a second vibrator device among the vibrator devices to the first vibrator device. The flexible member has predetermined rigidity in the predetermined direction and has rigidity, which is lower than the predetermined rigidity, in directions other than the predetermined direction.

First claim

What is claimed is:

1. A vibration actuator comprising:
vibrator devices that respectively have vibrators, each of which includes an elastic member and an electro-mechanical energy conversion element;
a contact member that contacts the vibrators and is movable in a predetermined direction relatively to the vibrators;
a restraint member that fixes a first vibrator device that is at least one of the vibrator devices to restrict a degree of freedom in the predetermined direction; and
a flexible member that has predetermined rigidity in the predetermined direction has rigidity, which is lower than the predetermined rigidity, in directions other than the predetermined direction, and connects a second vibrator device that is at least one of the vibrator devices to the first vibrator device.

2. The vibration actuator according to claim 1 , wherein the vibrator devices are arranged in series in the predetermined direction.

3. The vibration actuator according to claim 1 , wherein the contact member is moved relatively to the vibrators by thrust caused by vibration of each of the vibrators that occurs by applying alternating voltage to the electro-mechanical energy conversion element.

4. The vibration actuator according to claim 1 , wherein the flexible member guides the contact member in a direction perpendicular to the predetermined direction according to movement of the second vibrator device.

5. The vibration actuator according to claim 4 , wherein the flexible member has a rotation section that is rotatable around an axis parallel to the predetermined direction.

6. The vibration actuator according to claim 1 , wherein each of the vibrator devices has a holding member that holds each of the vibrators, and
wherein at least one of the vibrator devices has a contact-member supporter that is provided in the holding member and guides the contact member in the predetermined direction by restricting a degree of freedom of the contact member.

7. The vibration actuator according to claim 6 , wherein the first vibrator device fixed by the restraint member has the contact-member supporter.

8. The vibration actuator according to claim 6 , wherein the contact-member supporter is provided in the holding member of each of two vibrator devices located at both ends in the predetermined direction among the vibrator devices.

9. The vibration actuator according to claim 6 , wherein each of the vibrators functions as the contact-member supporter.

10. The vibration actuator according to claim 1 , wherein a center axis of the flexible member is arranged on a same plane as a friction sliding surface of the contact member that the vibrators contact.

11. The vibration actuator according to claim 1 , wherein each of the vibrator devices has two vibrators that are arranged so as to face each other across the contact member, and
wherein a center axis of the flexible member is located on a plane between two friction sliding surfaces of the contact member that the two vibrators contact.

12. The vibration actuator according to claim 1 , wherein each of the vibrator devices has a pressurizing member that presses each of the vibrators against the contact member and a reaction force receiving member that receives a reaction force against a pressure force applied by the pressurizing member.

13. The vibration actuator according to claim 12 , wherein the reaction force receiving member is a roller that contacts the contact member and is rotatable around a center axis perpendicular to the predetermined direction.

14. The vibration actuator according to claim 12 , wherein the elastic member has a projecting part that contacts the contact member, and
wherein vibration causing displacement in a direction parallel to a surface in contact with the contact member is excited at a front end of the projecting part in a case where alternating voltage is applied to the electro-mechanical energy conversion element.

15. The vibration actuator according to claim 14 , wherein the projecting part functions as the reaction force receiving member.

16. A drive device comprising:
one or more vibration actuators each of which comprising:
vibrator devices that respectively have vibrators, each of which includes an elastic member and an electro-mechanical energy conversion element;
a contact member that contacts the vibrators and is movable in a predetermined direction relatively to the vibrators to drive a target;
a restraint member that fixes a first vibrator device that is at least one of the vibrator devices to restrict a degree of freedom in the predetermined direction; and
a flexible member that has predetermined rigidity in the predetermined direction has rigidity, which is lower than the predetermined rigidity, in directions other than the predetermined direction, and connects a second vibrator device that is at least one of the vibrator devices to the first vibrator device; and

a main body to which the one or more vibration actuators are fixed by the restraint member.

17. The drive device according to claim 16 , wherein the main body has a contact-member supporter that guides the contact member in the predetermined direction by restricting a degree of freedom of the contact member.

18. The drive device according to claim 16 , wherein the vibration actuators are arranged on a circumference of a reference circle of a predetermined diameter when viewed from the predetermined direction.

19. A multi-axis stage unit comprising:
a stationary part;
a stage that is movable with respect to the stationary part; and
at least one vibration actuator that is provided in the stationary part and drives the stage, the vibration actuator comprising:
vibrator devices that respectively have vibrators, each of which includes an elastic member and an electro-mechanical energy conversion element;
a contact member that contacts the vibrators and is movable in a predetermined direction relatively to the vibrators to drive the stage;
a restraint member that fixes a first vibrator device that is at least one of the vibrator devices to restrict a degree of freedom in the predetermined direction; and
a flexible member that has predetermined rigidity in the predetermined direction has rigidity, which is lower than the predetermined rigidity, in directions other than the predetermined direction, and connects a second vibrator device that is at least one of the vibrator devices to the first vibrator device.

20. An articulated robot comprising:
joints;
movable parts that are connected by the joints; and
vibration actuators that drive the movable parts, each of the vibration actuators comprising:
vibrator devices that respectively have vibrators, each of which includes an elastic member and an electro-mechanical energy conversion element;
a contact member that contacts the vibrators and is movable in a predetermined direction relatively to the vibrators to drive the movable parts;
a restraint member that fixes a first vibrator device that is at least one of the vibrator devices to restrict a degree of freedom in the predetermined direction; and
a flexible member that has predetermined rigidity in the predetermined direction has rigidity, which is lower than the predetermined rigidity, in directions other than the predetermined direction, and connects a second vibrator device that is at least one of the vibrator devices to the first vibrator device.

Assignees

• Canon Kk

Inventors

• Arimitsu Yasumichi
• Fujimoto Kosuke

Classifications

• H02N2/0015

  using only bending modes · CPC title

• H02N2/026 Primary

  by pressing one or more vibrators against the driven body · CPC title

• H02N2/005

  Mechanical details, e.g. housings (casings for dynamo-electric machines H02K5/00) · CPC title

• B06B1/0644

  using a single piezoelectric element (B06B1/0688 takes precedence) · CPC title

• B06B1/045

  using vibrating magnet, armature or coil system · CPC title