Vibration actuator

{
  "publication_number": "US2024381777A1",
  "country": "US",
  "kind": "A1",
  "title": "Vibration actuator",
  "abstract": "A vibration actuator includes: a vibration body 1 including an elastic body 2 and an electric-mechanical energy conversion element 3 joined to the elastic body 2; and a contact body 4 that contacts the vibration body 1. The vibration body 1 and the contact body 4 move relative to each other in a predetermined direction. A vibration-damping member 25 is provided on a predetermined surface of the contact body 4 that is different from a contact surface that contacts the vibration body 1. The vibration-damping member 25 is constituted by a viscoelastic body or by combining the viscoelastic body and a reinforcement member.",
  "claims": [
    "1. A vibration actuator comprising: a vibration body including an elastic body and an electric-mechanical energy conversion element joined to the elastic body; and a contact body that contacts the vibration body, wherein the vibration body and the contact body move relative to each other in a predetermined direction, and wherein a vibration-damping member is provided on a predetermined surface of the contact body that is different from a contact surface that contacts the vibration body. 2. The vibration actuator according to claim 1, wherein the vibration-damping member includes a viscoelastic body made of a material different from a material of the contact body. 3. The vibration actuator according to claim 2, wherein the vibration-damping member includes the viscoelastic body and a reinforcement member, and wherein the viscoelastic body is interposed between the contact body and the reinforcement member. 4. The vibration actuator according to claim 3, wherein the vibration-damping member has a multilayer structure in which a plurality of the viscoelastic bodies and a plurality of the reinforcement members are alternately arranged. 5. The vibration actuator according to claim 1, wherein the vibration-damping member is provided on both of the predetermined surfaces that face each other. 6. The vibration actuator according to claim 1, wherein the vibration-damping member is provided on a side surface connected to the contact surface. 7. The vibration actuator according to claim 1, wherein the vibration-damping member is provided on a surface opposite to the contact surface. 8. The vibration actuator according to claim 1, wherein an end portion of the vibration-damping member does not protrude further than the contact surface. 9. The vibration actuator according to claim 1, wherein an end portion of the vibration-damping member protrudes further than the contact surface. 10. The vibration actuator according to claim 6, comprising: a holding portion that holds the vibration body, wherein a total dimension of the contact body and the vibration-damping member in a direction parallel to the contact surface is less than a dimension of the vibration body or a dimension of the holding portion in the direction parallel to the contact surface. 11. The vibration actuator according to claim 1, wherein the contact body is annular. 12. The vibration actuator according to claim 1, comprising a positioning structure for positioning the contact body and the vibration-damping member. 13. The vibration actuator according to claim 1, comprising: a displacement-detecting portion that detects relative displacement of the contact body and the vibration body, wherein the displacement-detecting portion includes a detector that moves together with the contact body or the vibration body and a scale that moves relative to the detector, and wherein a part of the vibration-damping member constitutes the scale. 14. The vibration actuator according to claim 1, wherein a vibration mode excited in the vibration body is an out-of-plane bending vibration mode in which a plurality of nodal lines are generated in the predetermined direction, and wherein a sum total of a length of the vibration-damping member in the predetermined direction is greater than or equal to ½ of a wavelength of a natural vibration mode excited in the contact body. 15. The vibration actuator according to claim 1, wherein a vibration mode excited in the vibration body is an out-of-plane bending vibration mode in which a plurality of nodal lines are generated in the predetermined direction, and wherein a sum total of a length of the vibration-damping member in the predetermined direction is greater than or equal to a length of an interval between the nodal lines that are adjacent to each other. 16. The vibration actuator according to claim 1, wherein a vibration mode excited in the vibration body is an out-of-plane bending vibration mode in which a plurality of nodal lines are generated in the predetermined direction, and wherein a sum total of a length of the vibration-damping member in the predetermined direction is greater than or equal to a center-to-center distance between two projecting portions that are provided on the elastic body and are caused to contact the contact body. 17. The vibration actuator according to claim 1, wherein a vibration mode excited in the vibration body is an out-of-plane bending vibration mode in which a plurality of nodal lines are generated in the predetermined direction, and wherein the vibration-damping member is provided at a position including an antinode of a natural vibration mode excited in the contact body. 18. The vibration actuator according to claim 1, wherein the vibration-damping member is joined to the predetermined surface. 19. A contact body unit comprising: a contact body that contacts a vibration body; and a vibration-damping member provided on a predetermined surface of the contact body that is different from a contact surface that contacts the vibration body. 20. An actuator unit, wherein the vibration actuator according to claim 1 is unitized by using an outer member, and a part of the contact body or a part of a vibration body unit including the vibration body is led to an outside of the outer member to allow connection of a load. 21. An apparatus comprising the vibration actuator according to claim 1. 22. The apparatus according to claim 21, wherein a plurality of the vibration actuators are arranged radially in a plane perpendicular to the predetermined direction. 23. A multi-axis stage comprising: the vibration actuator according to claim 1; a fixed portion to which the vibration actuator is fixed; and a stage that is connected to the contact body and moves in a predetermined direction relative to the fixed portion. 24. An articulated robot comprising the vibration actuator according to claim 1 as a driving source."
  ],
  "description_excerpt": "The present invention relates to a vibration actuator in which a vibration body and a contact body move relative to each other, a contact body unit, an actuator unit using the vibration actuator, an apparatus, a multi-axis stage unit, and an articulated robot.\n\nThere have been proposed: a vibration actuator that obtains thrust between a vibration body and a contact body by generating, in the vibration body, vibration in which different vibration modes are combined; and a vibration actuator that changes a frictional force between a vibration body and a contact body by causing excitation in a single vibration mode. PTL 1 discloses, regarding a vibration motor (corresponding to a vibration actuator) including a vibrator (corresponding to a vibration body) that generates an elliptic motion in which a plurality of different vibrations are synthesized, a configuration with which a vibration generated in a relative movement member (corresponding to a contact body) due to the elliptic motion generated by the vibrator is absorbed by providing a vibration-absorbing member between the relative movement member and a second base member.\n\nPatent Literature PTL 1: Japanese Patent Laid-Open No. 2000-324865 PTL 2: Japanese Patent Laid-Open No. 2018-140101 However, with the configuration disclosed in PTL 1, the output power per volume or per weight tends to be small, and the configuration has a problem in space efficiency. A first reason for this is that the second base member is necessary.",
  "cpc": [
    "H10N 30/2047",
    "B25J 9/12",
    "H02N 2/0015",
    "H02N 2/005",
    "H02N 2/026",
    "H02N 2/028",
    "H02N 2/103",
    "H02N 2/163",
    "H10N 30/886"
  ],
  "ipc": [
    "H10N 30/20",
    "H10N 30/88"
  ],
  "assignees": [
    "CANON KK"
  ],
  "inventors": [
    "ARIMITSU YASUMICHI"
  ],
  "filing_date": "2024-07-22",
  "publication_date": "2024-11-14",
  "priority_date": "2022-01-25",
  "application_number": "US-202418779501-A",
  "family_id": "87471094"
}