Rotary motor with ultrasonic actuator

Patent metadata

Field	Value
Publication number	US-11218089-B2
Application number	US-201816627021-A
Country	US
Kind code	B2
Filing date	Jun 22, 2018
Priority date	Jun 30, 2017
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

A rotary ultrasonic motor includes an ultrasonic actuator, a driven element, an inner casing member and an outer casing member. A piezoelectric or electrostrictive or magnetostrictive material is arranged between an excitation electrode and at least one general electrode. The ultrasonic actuator is between the inner and outer casing members of a casing, and is directly or indirectly in contact with the element to be driven, so that periodic deformations generated in the ultrasonic actuator by electrical excitation are transferable to the drive element. The ultrasonic actuator is mounted by a retaining device arranged on the casing with at least one retaining section which engages in a recess associated with a respective retaining section.

First claim

The invention claimed is:

1. A rotary ultrasonic motor comprising:
at least one ultrasonic actuator;
an element to be driven and a casing having an inner casing member and an outer casing member;
wherein said at least one ultrasonic actuator includes at least one of piezoelectric, electrostrictive and magnetostrictive material arranged between at least one excitation electrode and at least one general electrode;
wherein said at least one ultrasonic actuator is arranged in said casing between said inner casing member and said outer casing member and is directly or indirectly in contact with said element to be driven, so that periodic deformations generated in said at least one ultrasonic actuator by electrical excitation, will be transferable to drive said element to be driven; and
wherein said at least one ultrasonic actuator is mounted by a retaining device arranged on said casing with at least one retaining section configured to engage in a recess associated with a respective retaining section and disposed in said at least one ultrasonic actuator.

2. The rotary ultrasonic motor according to claim 1 , wherein said retaining device is formed by a screw, and said recess includes a thread configured for interacting with a thread of said screw.

3. The rotary ultrasonic motor according to claim 1 , wherein at least one of said inner casing member and said outer casing member comprise:
a threaded portion, and said recess is formed as a through hole, and said retaining device is formed as a screw and protrudes through said through hole, where a thread of said screw interacts with said threaded portion of at least one of said inner casing member and said outer casing member.

4. The rotary ultrasonic motor according to claim 1 , wherein at least one of said inner casing member and said outer casing member is embodied integrally formed with each other.

5. The rotary ultrasonic motor according to claim 1 , wherein said inner casing member and said outer casing member are connected to each other by way of web-shaped spring elements, where said at least one ultrasonic actuator is configured to be clamped between said web-shaped spring elements by damping elements arranged between said web-shaped spring elements and said at least one ultrasonic actuator.

6. The rotary ultrasonic motor according to claim 1 , wherein said at least one retaining section of said retaining device is formed integrally with at least one of said outer casing member and said inner casing member.

7. The rotary ultrasonic motor according to claim 1 , further comprising:
a bearing element configured for rotatably mounting said element to be driven, and arranged within at least one of said inner casing member and said outer casing member.

8. The rotary ultrasonic motor according to claim 1 , further comprising:
a clamping element arranged between said inner casing member and said outer casing member, and connected to at least one of said inner casing member and said outer casing member to allow displacement of said clamping element, at least in sections, relative to at least one of said inner casing member and said outer casing member, and to allow pressing of said at least one retaining section against said recess to occur with the displacement.

9. The rotary ultrasonic motor according to claim 8 , wherein said clamping element comprises:
at least one engagement section in engagement with an associated recess.

10. The rotary ultrasonic motor according to claim 9 , wherein said at least one ultrasonic actuator has at least one of a hollow cylindrical shape and a plate shape with two main surfaces that are largest in terms of area, and where said recess points from one of said two main surfaces to the other of said two main surfaces and extends as a through hole from one of said two main surfaces to the other of said two main surfaces.

11. The rotary ultrasonic motor according to claim 10 , further comprising:
at least two excitation electrodes on one of said two main surfaces of said at least one ultrasonic actuator respectively arranged spaced from each other due to a separation region disposed between them and
a recess embodied as a through hole, arranged between respectively adjacent excitation electrodes and intersecting the respective separation region.

12. The rotary ultrasonic motor according to claim 10 , further comprising:
at least one friction element arranged on at least one of two face surfaces of said at least one ultrasonic actuator connecting said two main surfaces for direct or indirect contact with said element to be driven.

13. The rotary ultrasonic motor according to claim 12 , wherein said at least one friction element is in contact with a friction ring, where said friction ring is arranged on a spring disk that is connected to said element to be driven and that presses said friction ring against said at least one friction element.

14. The rotary ultrasonic motor according to claim 10 , wherein said at least one ultrasonic actuator has a hollow cylindrical shape, and said at least one general electrode is arranged on one of said two main surfaces, that defines a first circumferential surface, and at least six substantially equally sized excitation electrodes are arranged on the other of said two main surfaces, that defines a second circumferential surface, evenly distributed over a circumference with a separation region disposed between respectively adjacent excitation electrodes, and wherein said at least one ultrasonic actuator further comprises:
three recesses distributed evenly over the circumference and embodied as through holes and
at least three friction elements respectively arranged on at least one face surface of said at least one ultrasonic actuator distributed evenly over the circumference and positioned adjacent to a respective separation region, where positions of said through holes and said at least three friction elements along the circumference differ from each other.

15. The rotary ultrasonic motor according to claim 10 , further comprising:
three substantially rectangular ultrasonic actuators, where respectively adjacent ultrasonic actuators define an angle of substantially 60° between them, where said at least one general electrode is respectively arranged on one of said two main surfaces and at least two substantially equally sized excitation electrodes are arranged on the other or said two main surfaces, where each of said three substantially rectangular ultrasonic actuators includes two recesses, each of said two recesses being arranged in a region of said at least two substantially equally sized excitation electrodes and embodied as through holes, and a respective friction element is arranged on one of a longer side surfaces of an ultrasonic actuator adjacent to a respective separation region.

16. The rotary ultrasonic motor according to claim 2 , wherein at least one of said inner casing member and said outer casing member comprise:
a threaded portion, and said recess is formed as a through hole, and said retaining device is formed as a screw and protrudes through said through hole, where a thread of said screw interacts with said threaded portion of at least one of said inner casing member and said outer casing member.

17. The rotary ultrasonic motor to claim 16 , wherein at least one of said inner casing member and said outer casing member is embodied integrally formed with each other.

18. The rotary ultrasonic motor according to claim 17 , wherein said inner casing member and said outer casing member are connected to each other by way of

Assignees

• Phys Instrumente Pi Gmbh & Co Kg

Inventors

• Koc Burhanettin
• Polzer Thomas

Classifications

• H02N2/0055

  Supports for driving or driven bodies; Means for pressing driving body against driven body · CPC title

• H02N2/10

  producing rotary motion, e.g. rotary motors · CPC title

• H02N2/103

  by pressing one or more vibrators against the rotor · CPC title

• H02N2/12 Primary

  Constructional details · CPC title

• H02N2/0045 Primary

  using longitudinal or radial modes combined with torsion or shear modes · CPC title