Vibration-type actuator, multi-axis stage, articulated robot, and continuum robot

Abstract

To provide a vibration type actuator capable of suppressing unnecessary vibration generated in the vibration type actuator and increasing output per volume, and to provide a device, a multiaxial stage unit, and an articulated robot.SOLUTION: A vibration-type actuator according to the present invention includes a vibrating body including an elastic body and an electromechanical energy conversion element, and a contact body in contact with the vibrating body, wherein the vibrating body and the contact body are moved relative to each other in a first direction by vibrating the vibrating body, wherein an endless viscoelastic body covering a side surface of the contact body is attached to a part of the contact body.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a vibration-type actuator in which a vibrating body and a contact body move relatively to each other, a multi-axis stage, an articulated robot, and a continuum robot. [Background technology]

[0002] Proposed vibration actuators include one that generates vibrations in a vibrating body that combine different vibration modes to generate thrust between the vibrating body and a contact body, and one that changes the frictional force between the vibrating body and a contact body by exciting it in a single vibration mode.

[0003] In Patent Document 1, a vibration absorbing member is provided between the relative moving member (contact body) and the second base member in order to avoid the generation of noise (also called squealing) caused by unnecessary vibrations and the reduction in drive efficiency. This configuration discloses a configuration in which unnecessary vibrations generated in the relative moving member (contact body) by the elliptical motion generated by the vibrator (vibrating body) are absorbed.

[0004] However, the configuration disclosed in Patent Document 1 tends to have low output per volume or weight, posing a problem in terms of space utilization efficiency. The first reason is that a second base member is required to support one surface of the second base member. The second base member is larger than the relative moving member (contact body), which increases the overall size of the ultrasonic motor (vibration actuator), making miniaturization difficult. The second reason is that a vibration absorbing member is provided over the entire surface between the relative moving member (contact body) and the second base member, which inevitably limits the surface that can be used for frictional sliding of the relative moving member (contact body). As a result, the surface facing the frictional sliding surface cannot be used for driving because the vibration absorbing member is attached to it. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-324865 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the above circumstances, an object of the present invention is to provide a vibration type actuator, a device, a multi-axis stage unit, and an articulated robot that can suppress unnecessary vibrations generated in a vibration type actuator and increase output per volume. [Means for solving the problem]

[0007] The vibration actuator of the present invention is a vibration actuator comprising a vibrating body including an elastic body and an electromechanical energy conversion element, and a contact body in contact with the vibrating body, in which the vibrating body and the contact body move relatively in a first direction by vibrating the vibrating body, and is characterized in that an endless viscoelastic body covering the side surface of the contact body is attached to a part of the contact body. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a small vibration type actuator that can suppress the generation of unwanted vibrations. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a diagram showing a schematic configuration of a vibrating body. [Figure 2] 3A and 3B are schematic diagrams illustrating vibration modes excited in a vibrating body. [Figure 3] 1A to 1C are a front view, a bottom view, and a side view showing a schematic configuration of a vibration type actuator according to a first embodiment. [Figure 4] 1 is a front view showing a schematic configuration of a vibration type actuator according to a first embodiment. [Figure 5] 10A and 10B are diagrams illustrating the configuration of a connecting portion that connects vibrating body units and a modified example thereof. [Figure 6]1A to 1C are a plan view, a front view, and a side view showing a schematic configuration of a vibration type actuator according to a first embodiment. [Figure 7] FIG. 10 is a front view showing a schematic configuration of a vibration type actuator according to a second embodiment. [Figure 8] 10A and 10B are a plan view and a front view showing a schematic configuration of a vibration type actuator according to a second embodiment. [Figure 9] 10A to 10C are a plan view, a front view, and a bottom view showing a schematic configuration of a contact body unit and a contact body according to a second embodiment. [Figure 10] 10A and 10B are schematic diagrams illustrating a method for supporting a contact body by a plurality of vibrating bodies. [Figure 11] 10A and 10B are diagrams illustrating an example of a configuration in which a displacement detection means is provided in a vibrating body unit. [Figure 12] 10A and 10B are diagrams illustrating a schematic configuration of an actuator unit according to a third embodiment. [Figure 13] FIG. 10 is a plan view showing a schematic configuration of an apparatus according to a fourth embodiment. [Figure 14] FIG. 10 is a diagram illustrating a schematic configuration of an apparatus according to a fifth embodiment. [Figure 15] FIG. 13 is a plan view showing a schematic configuration of a multi-axis stage according to a sixth embodiment. [Figure 16] FIG. 13 is a plan view showing a schematic configuration of an articulated robot according to a seventh embodiment. [Figure 17] FIG. 13 is a plan view showing a schematic configuration of a continuum robot according to an eighth embodiment. [Figure 18] FIG. 13 is a perspective view showing a schematic configuration of a wire-driven manipulator of a continuum robot according to an eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0011] First, the vibrating body and contact body used in common in the vibration actuators according to the embodiments described below will be described. Fig. 1(a) is a plan view showing the schematic configuration of a vibrating body 1 constituting a vibration actuator, Fig. 1(b) is a front view of the vibrating body 1, and Fig. 1(c) is a side view of the vibrating body 1.

[0012] For ease of explanation, as shown in FIGS. 1(a) to 1(c), a Cartesian coordinate system consisting of an x-axis (x direction), a y-axis (y direction), and a z-axis (z direction) is set for the vibrating body 1. The z-direction is the thickness direction of the vibrating body 1 and is the protruding direction of the protrusions 2a (details of which will be described later) provided in two places. The y-direction is the longitudinal direction of the vibrating body 1 and is the direction connecting the two protrusions 2a. The x-direction is the lateral direction (width direction) of the vibrating body 1 and is a direction perpendicular to the y- and z-directions. For each direction shown in FIG. 1, the direction from the start point to the end point of the arrow indicating each direction is defined as the positive direction (+ direction), and the direction from the end point to the start point is defined as the negative direction (- direction).

[0013] The vibrating body 1 includes an elastic body 2 and an electromechanical energy conversion element 3 bonded to the elastic body 2. The electromechanical energy conversion element 3 is, for example, a piezoelectric element that converts voltage into force through the inverse piezoelectric effect. It is configured by providing electrodes to which a predetermined voltage is applied on the front and back surfaces of a rectangular thin plate of piezoelectric ceramic. The elastic body 2 has a protrusion 2a, a support support 2b, a support end 2c, and a base 2d. The two protrusions 2a are provided on the rectangular flat base 2d, protruding in the +z direction, on the surface opposite to the surface to which the electromechanical energy conversion element 3 is bonded. The protrusions 2a and the base 2d may be integrally formed by pressing or the like, or may be provided by bonding a protruding member to the base 2d by a predetermined method. The support end 2c is a rectangular flat plate-shaped portion used to secure the vibrating body 1 to the holder 8 (described later). The support support 2b is a rectangular flat plate-shaped portion that connects the base 2d and the support end 2c.

[0014] The protrusion 2a will now be described in more detail. FIG. 2(c) is a cross-sectional view showing the schematic structure of the protrusion 2a. A friction material 2f is provided on the surface of the base material 2e of the protrusion 2a. The material of the base material 2e is the same as that of the base portion 2d (not shown in FIG. 1(d)). When martensitic stainless steel is used for the base material 2e, the friction material 2f can be made of an electroless nickel plating film, a chrome plating film, a hardened layer obtained by quenching, a nitride film obtained by ion nitriding, or the like. Alternatively, a fiber-reinforced engineering plastic such as PEEK-CF30 or hard ceramics can be used for the base material 2e, allowing the base material 2e to double as the friction material 2f (in this case, there is no distinction between the base material 2e and the friction material 2f).

[0015] Next, we will explain the two vibration modes excited in the vibrating body 1. Fig. 2(a) is a schematic diagram explaining the first vibration mode excited in the vibrating body 1, and Fig. 2(b) is a schematic diagram explaining the second vibration mode excited in the vibrating body 1. Note that the deformation of the vibrating body 1 is exaggerated in Fig. 2. For ease of explanation, Fig. 2 also shows a contact body 4 that comes into contact with the vibrating body 1 and receives a thrust (frictional driving force) from the vibrating body 1.

[0016] The contact body 4 is a member that is long in the y direction in the figure and is configured to come into contact with the protrusion 2a of the vibrating body 1. The vibrating body 1 and the contact body 4 are configured to be able to move relatively in the y direction due to vibrations generated in the vibrating body 1. The contact between the contact body 4 and the vibrating body 1 is not limited to direct contact where no other member is interposed between the contact body 4 and the vibrating body 1. The contact between the contact body 4 and the vibrating body 1 may also be indirect contact where another member is interposed between the contact body 4 and the vibrating body 1, as long as the vibrations generated in the vibrating body 1 cause the vibrating body 1 and the contact body 4 to move relatively.

[0017] The "other members" are not limited to members independent of the contact body and the vibrating body (for example, high-friction materials made of sintered bodies). The "other members" may also be surface-treated portions formed on the contact body or the vibrating body by plating, nitriding, or the like.

[0018] The first vibration mode shown in Fig. 2(a) is a second-order out-of-plane bending vibration mode in which three nodal lines approximately parallel to the x-direction are generated in the base portion 2d, and this vibration mode excites vibrations that displace in the y-direction at the tips of the two protrusions 2a. On the other hand, the second vibration mode shown in Fig. 2(b) is a first-order out-of-plane bending vibration mode in which two nodal lines approximately parallel to the y-direction are generated in the base portion 2d, and this vibration mode excites vibrations that displace in the z-direction at the tips of the two protrusions 2a.

[0019] When vibrations in both the first and second vibration modes are excited by applying multiple alternating voltages with different phases to the electromechanical energy conversion element 3, elliptical motion can be generated in the yz plane at the tips of the two protrusions 2a. This elliptical motion in the yz plane applies a thrust force to the contact body 4 in the y direction, and as a result, it becomes possible to move the vibrating body 1 and the contact body 4 relative to each other in the y direction.

[0020] When no voltage is applied to the electromechanical energy conversion element 3, the static friction force between the protrusion 2a and the contact body 4 acts as a holding force that maintains the relative position of the vibrating body 1 and the contact body 4. Furthermore, by adjusting the voltage applied to the electromechanical energy conversion element 3 to adjust the amplitude of the vibration excited in the vibrating body 1, the contact time between the protrusion 2a and the contact body 4 can be adjusted, thereby changing the apparent friction force. For example, by exciting only vibration in the second vibration mode in the vibrating body 1 and increasing the vibration amplitude, the friction force generated between the protrusion 2a and the contact body 4 can be reduced.

[0021] By performing these controls, for example, in a configuration in which the contact body 4 moves relative to the vibrating body 1, it is possible to adjust the magnitude of the reaction force when an external force other than the contact pressure with the vibrating body 1 is applied to the contact body 4 to move the contact body 4. For example, it is possible to adjust the operation reaction force that the user receives when the user directly applies an external force to the contact body 4 to move the contact body 4.

[0022] In the vibration actuator shown in Fig. 2, the tip of the protrusion 2a is in contact with the contact body 4. The contact body 4 is provided with a friction material 4a on the surface (friction sliding surface) that comes into contact with the protrusion 2a, and a friction material 2f is provided on the surface of the protrusion 2a. This makes it possible to obtain stable friction sliding characteristics between the elastic body 2 and the contact body 4. The material and forming method of the friction material 4a are similar to the material and forming method of the friction material 2f.

[0023] Next, the materials used for the vibrating body 1 and the contact body 4 will be described. Examples of materials used for the elastic body 2 include highly tough ceramics such as martensitic stainless steel and partially stabilized zirconia (PSZ), which have low vibration loss. Other examples include engineering plastics (FRP) such as polyether ether ketone (PEEK-CF30) reinforced with approximately 30 wt% carbon fiber, semiconductors such as silicon carbide (SiC), and aluminum alloys. Piezoelectric ceramics such as lead titanate-lead zirconate (PZT) are used for the electromechanical energy conversion element 3. Examples of materials used for the contact body 4 include martensitic stainless steel, aluminum alloys, FRP such as PEEK-CF30, fine ceramics such as PSZ and alumina (aluminum oxide). Note that the materials used for the vibrating body 1 and the contact body 4 are not limited to those listed here. [Example]

[0024] 3 is a schematic illustration of a contact body 4 and a vibrating body 1 for explaining a vibration actuator according to a first embodiment of the present invention. The vibration actuator of this example comprises a vibrating body including an elastic body and an electromechanical energy conversion element, and a contact body that is long in a predetermined direction and in contact with the vibrating body. This vibration actuator is configured so that the vibrating body and the contact body move relative to each other in the predetermined direction due to vibration of the vibrating body. A feature of this vibration actuator is that the end of the long contact body is covered with a viscoelastic body in the circumferential direction relative to the predetermined direction.

[0025] FIG. 3(a) is a front view of a contact body 4 with cylindrical viscoelastic bodies 6a and 6b fitted at both ends and one vibrator 1 pressed against the contact body 4. FIGS. 3(h) and 3(i) are right side views. The x, y, and z directions are set as shown in FIG. 3 according to the x, y, and z directions set for the vibrator 1. The y direction is the left-right direction of the vibration actuator, including the vibration actuators according to other embodiments described below, with the +y side defined as the right side and the -y side defined as the left side. The z direction is the up-down direction of the vibration actuator, with the +z side defined as the upper side and the -z side defined as the lower side. An example of a method for pressing the vibrator 1 against the contact body 4 will be described later. FIG. 3(b) is a front view of the contact body 4, exaggerating the out-of-plane bending mode occurring in the contact body 4. When the first vibration mode, the second vibration mode, or both are excited in the vibrating body 1, if the frequency of that vibration mode is close to the natural frequency of the natural vibration mode of the contact body 4, the natural vibration mode is excited in the contact body 4. For example, when an out-of-plane vibration mode is excited in the contact body 4, as shown in Figure 3(b), which vibrates in the z direction with a wavelength λ relative to a plane parallel to the xy plane, the contact body 4 and the protrusion 2a of the vibrating body 1 intermittently alternate between contact and non-contact states. This causes an abnormal banging noise and a decrease in thrust. Furthermore, the difference between the drive frequency excited in the vibrating body 1 and the natural frequency of the natural vibration mode excited in the contact body 4 can cause squealing and a decrease in thrust. As shown in Figure 3(a), cylindrical viscoelastic bodies 6a and 6b are fitted into the contact body 4 and tightly adhere to it. This allows the contact body 4 and the viscoelastic body to come into close contact with each other at the location where strain occurs in response to deformation of the contact body 4, which is a natural vibration mode that occurs in the contact body 4 as unwanted vibration. As a result, the expansion and contraction of the viscoelastic bodies 6a and 6b can be used to absorb excitation energy and reduce the vibration amplitude of unwanted vibration. A preferred shape of the viscoelastic body will now be described. In this embodiment, the viscoelastic bodies 6a and 6b are cylindrical, and the contact body 4 is a rod-like rectangular parallelepiped. However, it is preferable that the viscoelastic bodies 6a and 6b contact the contact body on four surfaces. In other words, it is preferable that the total circumferential outer dimensions of the contact body 4 in a cross section parallel to the xz cross section be slightly longer than the inner circumference of the viscoelastic bodies 6a and 6b when not attached.Generally, simply attaching a viscoelastic body based on its adhesive properties is difficult to achieve perfect adhesion between the viscoelastic body and the distorted portion of the contact body. The presence of a small air gap makes it difficult to absorb the vibration energy described above, reducing the effectiveness of suppressing unwanted vibrations. Furthermore, when attaching a viscoelastic body using adhesive or other means, the presence of an adhesive layer between the viscoelastic body and the contact body makes the viscoelastic properties of the adhesive layer dominant over the viscoelastic properties of the viscoelastic body, preventing the high vibration-damping performance of materials such as butyl rubber. The present invention utilizes the elasticity of the viscoelastic body to use a tubular viscoelastic body whose relaxed cross-sectional area is smaller than the xz cross-sectional area of ​​the contact body 4. In other words, when the viscoelastic body is not attached to the contact body, the inner circumference of the cylindrical member is smaller than the sum of the lengths around the contact body in a cross section normal to a specific direction.

[0026] By attaching the holes to the contact body while extending them radially, it is possible to prevent the interposition of air gaps or adhesive layers and increase the area of ​​contact between the inside of the viscoelastic bodies 6a and 6b and the contact body 4. Furthermore, the longer the y-direction length of the viscoelastic bodies 6a and 6b, the more areas where strain occurs in the contact body due to unwanted vibrations can be covered. The increased absorption of vibration energy by the viscoelastic bodies enhances the effectiveness of suppressing unwanted vibrations. For example, if the y-direction dimensions of the two viscoelastic bodies 6a and 6b shown in FIG. 3(a) are L1 and L2, respectively, the sum of L1 and L2 is preferably equal to or greater than half the wavelength (λ / 2) of the vibration wave of the vibration mode of the contact body excited by the vibration shown in FIG. 3(b). Another criterion for determining the dimensions of the viscoelastic bodies is that the sum of L1 and L2 is preferably equal to or greater than the distance between adjacent protrusions 2a, which corresponds to approximately one wavelength of the first vibration mode exciting the vibrating body 1. When a viscoelastic body is provided only on one end, not both ends, the y-direction dimension of the viscoelastic body should be equal to or greater than the sum of L1 and L2. Furthermore, the total length of the y-direction dimension of the viscoelastic body should preferably be equal to or greater than the distance between adjacent nodal lines in the vibration generated in the vibrator.

[0027] Furthermore, it is preferable that the total length of the viscoelastic body in the y direction is equal to or greater than the distance between the centers of adjacent protrusions on the elastic body that constitutes the vibrator.

[0028] Next, the location of the viscoelastic body is preferably a location including the antinode of the vibration mode, where the contact body 4 is most distorted by unwanted vibrations, making it possible to more effectively damp unwanted vibrations. Materials suitable for the viscoelastic body are described below. The viscoelastic body is a material that has both viscosity and elasticity, and rubber or resin is suitable. Particularly suitable rubber materials include butadiene rubber, butyl rubber, and silicone rubber, which have high vibration-damping performance. A viscoelastic body can be formed inexpensively by cutting a hollow (tube-shaped) rubber or resin material. By fitting the cylindrical viscoelastic bodies 6a and 6b shown in FIG. 3(a) as described above, unwanted vibrations can be suppressed without increasing the size of the vibration actuator.

[0029] Next, the width dimensions of the contact body 4 and the viscoelastic body 6 will be described with reference to Figures 3(h) and 3(i). Figure 3(h) is a right side view of the vibrating body 1 when supported by a holding part 8, which will be described later. If the width dimensions in the x direction of the contact body 4, the viscoelastic body 6, and the holding part 8 are W4, W6, and W8, respectively, as shown in Figure 3(h), it is possible to miniaturize the vibration type actuator by making W4 ≦ W8 or W6 ≦ W8.

[0030] That is, in the cross section of the vibration actuator perpendicular to the predetermined direction, the width of the viscoelastic body can be made smaller than the width of the vibrating body or the width of the holding portion, thereby making it possible to reduce the size of the vibration actuator.

[0031] Furthermore, as shown in FIG. 3(i), if the width dimension of the vibrating body 1 in the x direction is W1, then by making W4≦W1 or W6≦W1, it is possible to further reduce the size of the vibration type actuator.

[0032] Next, an embodiment of a viscoelastic body for further enhancing the suppression effect of unwanted vibrations in this embodiment will be described with reference to FIGS. 3(c) to 3(g). FIG. 3(c) is a front view of a vibration actuator illustrating a state in which, in addition to the configuration of the viscoelastic body shown in FIG. 3(a), a viscoelastic body 6c is attached to the opposing surface of the friction sliding surface where the vibrator 1 and the contact body 4 contact. The configuration of the viscoelastic body shown in FIG. 3(c) can enhance the effect of suppressing unwanted vibrations generated in the contact body 4 compared to the configuration of the viscoelastic body shown in FIG. 3(a). In this case, the viscoelastic bodies 6a, 6b, and 6c may be formed separately or integrally. The surface of the contact body 4 where the vibrator 1 and the contact body 4 contact each other has an exposed region in the y-axis direction where no viscoelastic body is provided. This exposed region is provided to a length that does not hinder the relative movement between the vibrator 1 and the contact body 4 in the y-axis direction and in the circumferential direction relative to the y-axis. The length of the exposed area in the y-axis direction is preferably configured to be longer than the range of relative movement between the vibrating body 1 and the contact body 4, and the width of the exposed area in the x-axis direction is preferably configured to be longer than the width of the vibrating body 1 itself or the width of the protrusion 2a.

[0033] Figures 3(d) and 3(e) show another example of the configuration of a vibration actuator. Figure 3(d) is a front view of the vibration actuator, showing a viscoelastic body 6d attached to the contact body 4, and Figure 3(e) is a bottom view. The viscoelastic body 6d has a length L4 in the y direction and a window portion on the bottom surface of the center portion to form an exposed area L3 in the y direction. As shown in the figure, by attaching the viscoelastic body 6d to the contact body 4, the friction sliding surface 4b is exposed, allowing contact with the vibrating body 1. This vibration actuator can more effectively suppress unwanted vibrations generated in the contact body 4 than the vibration actuator configurations shown in Figures 3(a) and 3(c). In addition, the viscoelastic body can be inexpensively formed by a simple method, such as cutting out a portion of a tubular rubber or resin material using a die.

[0034] Figures 3(f) and 3(g) show further examples of the configuration of a vibration actuator. The configuration of the viscoelastic body 6f shown in Figures 3(f) and 3(g) enables even greater suppression of unwanted vibrations than the vibration actuator shown in Figures 3(d) and 3(e). Figure 3(f) is a front view of the vibration actuator, showing the viscoelastic body 6f attached to the contact body 4, and Figure 3(g) is a bottom view. Like the viscoelastic body 6d, the viscoelastic body 6f also has a length dimension L3 in the y direction and a window portion with a dimension L4 in the y direction provided on the central underside. As shown in the figure, the window portion of the viscoelastic body 6f has a smaller dimension in the x direction than the viscoelastic body 6d. In other words, the viscoelastic body 6f covers a portion of the friction sliding surface 4b and covers the contact body 4 to the extent that contact between the friction sliding surface 4b and the tip of the protrusion 2a of the vibrating body 1 is not obstructed. That is, the viscoelastic body 6f is fitted into the contact body 4 so that the friction sliding surface 4b is exposed over a length substantially equal to the width of the vibrating body 1 and slightly wider than the width of the vibrating body 1. This vibration actuator configuration can more effectively suppress unwanted vibrations occurring in the contact body 4 than the vibration actuator configurations shown in FIGS. 3(d) and 3(e). Furthermore, it can also more effectively suppress unwanted vibrations caused by multiple vibration modes, such as in-plane vibration and torsional vibration. Furthermore, because the window portion of the viscoelastic body 6f has a smaller dimension in the x-direction than the viscoelastic body 6d, it can utilize the contractile force of the viscoelastic body to achieve better adhesion to the contact body than the viscoelastic body 6d, thereby enhancing the effectiveness of suppressing unwanted vibrations. Similarly, in this case, the viscoelastic body can be formed inexpensively by a simple method, such as cutting out a portion of a tubular rubber or resin material using a die.

[0035] In the above example, the out-of-plane bending vibration mode occurring in the contact body 4 in FIG. 3(b) has been described as an example, but the present invention is also effective for other natural vibration modes such as in-plane vibration mode and torsional vibration mode. For in-plane vibration, torsional vibration, and other vibrations, vibration suppression similar to that for out-of-plane vibration is possible by providing a viscoelastic body so that it includes antinodes with large strain. As shown in FIGS. 3(c) to 3(g), the viscoelastic body is adhered to the end portion and the side surface of the contact body 4 other than the friction sliding surface. This allows unwanted vibrations caused by multiple vibration modes with different positions of the antinodes where large strain occurs to be suppressed by covering each antinode position.

[0036] Although examples of the configuration of the viscoelastic body have been described above, a configuration in which the viscoelastic body does not cover the very end of the long contact body may also be employed, as in the examples shown in FIG. 3. The effect of covering the very end of the contact body with a viscoelastic body on reducing unwanted vibrations is small. Therefore, a configuration in which the viscoelastic body does not cover the very end of the long contact body is also within the scope of the present invention. In this example, an example was given in which the xz cross section of the contact body is rectangular, and four side surfaces other than the surface parallel to the xz plane (= the very end) are covered to improve adhesion between the contact body and the viscoelastic body.

[0037] Next, a specific example of the support structure for the contact body 4 and the vibrating body 1 in the vibration actuator 101 of this embodiment will be described with reference to FIGS. 4 to 6. FIG.

[0038] 4 is a front view showing a schematic configuration of a vibration actuator 101 according to the first embodiment. The vibration actuator 101 includes a vibrating body unit 5 including a vibrating body 1, and a contact body 4 that comes into contact with the vibrating body 1 of the vibrating body unit 5.

[0039] The vibrating body unit 5 includes the vibrating body 1, a nonwoven fabric 16, a pressure applying unit 7, a holding unit 8, a rotation support unit 9, and a reaction force receiving unit 10. The vibrating body unit 5 has a pressure applying support structure capable of exciting vibrations in the vibration modes shown in FIG. 2. In one vibrating body unit 5, the support end 2c of the elastic body 2 constituting the vibrating body 1 is fixed to the upper surface of the wall on the y-direction side, which is the side wall of the holding unit 8. A nonwoven fabric 16 is disposed on the back side of the electromechanical energy conversion element 3 (the surface opposite to the surface bonded to the elastic body 2). The nonwoven fabric 16 is a cloth-like member made of a nonwoven fabric material such as wool felt or glass wool, and supports the vibrating body 1 while maintaining the vibration mode generated in the vibrating body 1. The pressure applying unit 7 presses the vibrating body 1 against the contact body 4 via the nonwoven fabric 16, causing the protrusion 2a of the vibrating body 1 to come into contact with the contact body 4. Note that since the vibrating body 1 is fixed to the holding unit 8, the holding unit 8 presses the vibrating body 1 toward the contact body 4 together.

[0040] Here, a method for installing the nonwoven fabric 16 will be described. Fig. 5(a) is a partial front view of the vibrating body unit 5, and Fig. 5(b) is a bottom view of this vibrating body unit 5. A through-hole 8e that penetrates in the z direction is provided in the holding portion 8, and when the holding portion 8 is viewed from the -z direction with the vibrating body 1 held by the holding portion 8, the electromechanical energy conversion element 3 is exposed from the through-hole 8e. The nonwoven fabric 16 (hatched area in Fig. 5(b)) is installed inside the through-hole 8e so as to be in contact with the electromechanical energy conversion element 3.

[0041] Although not shown, a flexible wiring board for supplying power to the electromechanical energy conversion element 3 is actually attached to the back surface (surface on the -z direction side) of the electromechanical energy conversion element 3. Therefore, to be precise, the nonwoven fabric 16 is placed so as to be in contact with the flexible wiring board attached to the electromechanical energy conversion element 3.

[0042] The pressure applying unit 7 applies a predetermined pressure to the contact body 4 via the nonwoven fabric 16 by pressing the protrusion 2a of the vibrating body 1 against the contact body 4. The pressure applying unit 7 is made up of elastic parts such as a coil spring, a leaf spring, a disc spring, a wave washer, rubber, an air tube, etc. that exert a restoring force in the z direction. Fig. 4 shows an example in which a compression coil spring is used for the pressure applying unit 7.

[0043] The reaction force receiving portion 10 supports the rotation support portion 9, and the rotation support portion 9 is configured to be rotatable like a roller relative to the reaction force receiving portion 10. The reaction force receiving portion 10 and the rotation support portion 9 are arranged so as to be in contact with the upper surface of the contact body 4 in the Z direction. This is the side of the surface opposite to the contact surface with the protrusion 2a of the contact body 4. The protrusion 2a of the vibrating body 1 receives a reaction force of the pressure force pressing against the contact body 4. In this way, the contact body 4 is supported by the pair of the vibrating body unit 5, the reaction force receiving portion 10, and the rotation support portion 9.

[0044] On the other hand, two opposing pairs of reaction force receiving parts 10 and rotation support parts 9 are provided at positions offset in the negative y-axis direction from the above pairs, so that the contact body is sandwiched in the z-direction by three rotation support parts 9 and one vibrator unit 5. In the vibration actuator 101, the reaction force receiving parts 10 are attached to a support member 15, and the rotation support parts 9 are supported rotatably about an axis parallel to the x-axis, forming a roller. The support member 15 is a base for assembling various components that make up the vibration actuator 101. The support member 15 can be configured to include the reaction force receiving parts 10, the rotation support parts 9, the vibrator unit 5, and part of the contact body 4.

[0045] The vibration actuator 101 is mounted on the equipment by fixing the support member 15 to the frame or the like of the equipment (not shown), and the contact body 4 can be configured to move in the y direction relative to the fixed support member 15.

[0046] The contact body 4 is supported by the support member 15 in a state where it can move in the y direction by thrust received from the vibrators 1 that each vibrator unit 5 has. Specifically, four rollers that can rotate around axes parallel to the z axis are provided on the support member 15 as contact body support parts 12 that movably support the contact body 4. The four contact body support parts 12 act as linear guides that enable movement of the contact body 4 in the y direction while restricting the degree of freedom of the contact body 4 in the x direction.

[0047] The holder 8 of the vibrating body unit 5 is attached to the support member 15 by a connecting portion 14. FIG. 5(c) is a perspective view showing a schematic configuration of the connecting portion 14. The connecting portion 14 has a link member 14b (joint portion) having two holes formed at a predetermined interval so as to penetrate the link member 14 in the x direction, and cylindrical pins 14a (shaft portions) that are inserted into the two holes of the link member 14b and attached to the link member 14b in approximately parallel relation. The two pins 14a are fixed to the link member 14b through the respective holes of the link member 14b. The two pins 14a and the link member 14b may be molded integrally (seamlessly) in an H-shape when viewed from the z direction.

[0048] One of the two pins 14a is positioned at a position a distance a in the +z direction from the reference origin O of the support member 15 shown in Fig. 4, thereby allowing the connecting portion 14 to have a degree of freedom of rotation about the central axis of the pin 14a positioned on the support member 15. Meanwhile, the center of the contact body 4 is positioned at a position a distance b in the +z direction from the center of the pin 14a positioned on the support member 15. In this way, the contact body 4 is accurately positioned at a position a distance a + b in the +z direction from the reference origin O of the support member 15. With the above configuration, the vibrating body unit 5 is slidable in the z direction, and even if the contact body 4 has an undulating shape in the yz plane due to manufacturing errors or the like, the vibrating body unit 5 can press against the contact body 4 by following the shape of the contact body 4.

[0049] Next, a modified example of the vibration actuator 102 according to the first embodiment will be described with reference to Fig. 6. This differs from the vibration actuator 102 described above in that both ends of the contact body 4 are fixed to support members 15.

[0050] 6(a) and 6(b) are a plan view and a front view, respectively, showing the schematic configuration of a vibration actuator 102. The vibration actuator 102 is an embodiment that includes a vibrating body unit 11 and a contact body 4 that comes into contact with the vibrating body 1 of the vibrating body unit 5, in which the contact body 4 is fixed and the vibrating body 1 moves relatively. Furthermore, among the components of the vibration actuator 102, those that correspond to the components of the vibration actuator 101 (see FIG. 4) will be given the same names and symbols, and explanations of their common functions and configurations will be omitted.

[0051] The vibration actuator 102 includes a vibrating body unit 11 and a contact body 4. In the vibration actuator 102, both ends of the contact body 4 are fixed to support members 15, and two viscoelastic bodies 6 are fitted at the positions of the antinodes of an out-of-plane vibration mode that occurs in the contact body 4 at a frequency close to the drive frequency applied to the vibrating body 1. The vibrating body unit 11 includes the vibrating body 1, a spacer 19, a pressure member 13, a rotation support member 9, and a holding member 18 for integrating these into a unit. In the vibrating body unit 11, a spacer 19 with a nonwoven fabric 16 attached thereto is disposed inside the holding member 18. Then, with the nonwoven fabric 16 in contact with the electromechanical energy conversion element 3 that constitutes the vibrating body 1, the support ends 2c at both ends of the vibrating body 1 in the y direction are fixed to the holding member 18. A schematic configuration for explaining the support relationship between the vibrating body unit 11 and the contact body 4 is shown in FIG. 6(c).

[0052] 6(c), an opening 18a is provided in the holding portion 18, and the dimension of the opening in the x direction is set to be larger than the width dimension in the x direction of the contact body 4. By providing an appropriate gap in this way, the opening 18a functions as a linear guide for moving the vibrating body unit 11 in the y direction.

[0053] A rotation support part 9 is provided on the opposite side of the contact surface between the contact body 4 and the protrusion 2a (above (+z side) of the contact body 4), and receives a reaction force of the force pressing the protrusion 2a of the vibrating body 1 against the contact body 4. The rotation support part 9 of the vibration actuator 101 is supported so as to be rotatable around an axis parallel to the x-axis, and a compression coil spring is arranged as a pressure part 13 relative to the rotation support part 9. In this way, the pressure reaction force of the pressure part 13 (the force of the compression coil spring trying to expand in the z direction) presses the rotation support part 9 against the contact body 4, and the tip of the protrusion 2a of the vibrating body 1 is pressed against the contact body 4.

[0054] With the above configuration, in the vibration actuator 102, the vibrating body unit 11 can move in the y direction relative to the contact body 4. At this time, as shown in Fig. 6(a), by providing an opening 15a in the support member 15, the upper surface of the vibrating body unit 11 can be exposed to the outside, and the vibrating body unit 11 can be connected to an object to be driven (not shown).

[0055] In this example, we described an embodiment in which a cylindrical or tubular viscoelastic body made of rubber or the like is fitted into the contact body. However, this is not a limitation. Other methods for forming the viscoelastic body include the following: A first method involves wrapping a tape-like viscoelastic body made of an adhesive and a substrate around the contact body. This method can be easily performed after assembling the vibration actuator, making it effective as an emergency measure for noise during operation. By appropriately selecting the thickness and material of the substrate, unwanted vibrations can be effectively suppressed. A second method involves dipping the contact body into liquid rubber or resin. While the outermost edge of the contact body may be covered with the viscoelastic body, this does not significantly reduce the effectiveness of the viscoelastic body in suppressing unwanted vibrations. In dipping, if there are areas where adhesion of the viscoelastic body would cause problems, a mask can be applied to the contact body in advance, and the mask can be removed after the dipping process to avoid localized viscoelastic body coverage. A third method involves insert molding, in which the contact body is placed in a mold and a heated, molten resin material is injected around the contact body to form an integrated mold. As a fourth formation method, the contact body and viscoelastic body can be molded by two-color molding (double molding). For example, if a resin material is used for the contact body as the primary molding, PEEK (polyether ether ketone) reinforced by approximately 30% carbon fiber can be selected. Alternatively, an elastomer can be used for the viscoelastic body as the secondary molding. In this case, the carbon fiber filling is expected to improve the rigidity of the contact body and the wear resistance and sliding properties of the friction sliding surface. Forming the viscoelastic body by these other methods not only improves mass productivity and enables the formation of viscoelastic bodies at low cost, but also enhances the adhesion of the viscoelastic body to the contact body, preventing detachment and misalignment of the viscoelastic body. Furthermore, when forming the viscoelastic body using a mold, the relative positions of the elastomer and contact body can be precisely determined, making it possible to form viscoelastic bodies with complex shapes.

[0056] In this example, a linear contact body with the y direction as the longitudinal direction was described, but the present invention is not limited to a linear contact body. The contact body can have any curved shape, and unnecessary vibrations can be suppressed by fitting a viscoelastic body into a curved contact body in the same way. Even when a curved contact body is used, the vibrator can be fixed and the contact body can be on the driven side. In this case, it is preferable to form a contact body support part that matches the shape of the contact body. Conversely, the contact body can be fixed and the vibrator can be on the driven side, in which case the vibrator unit moves relatively along the curved contact body. [Example]

[0057] A second embodiment of the present invention will be described using Figures 7 to 11. As shown in the figures, the Cartesian coordinate system set for each vibration actuator conforms to that of the first embodiment, and similar Cartesian coordinate systems are set for the vibration actuators and actuator units according to each embodiment described below. Furthermore, among the components of the vibration actuator, components that have the same functions as those in the first embodiment will be given the same names and symbols, and descriptions of their common functions and configurations will be omitted.

[0058] 7 is a front view showing a schematic configuration of a vibration actuator 201 according to the second embodiment. The vibration actuator 201 includes two vibrating body units 21 and a contact body 4 that comes into contact with the vibrating body 1 of the vibrating body unit 21.

[0059] Each vibrating body unit 21 has two vibrating bodies 1, nonwoven fabric 16, a pressure member 17, and a holding member 8, and the contact body 4 is sandwiched and pressed between one vibrating body 1 and the other opposing vibrating body 1 by a configuration in which the end of the pressure member 17 is hooked onto a hook 8a provided on the side of the holding member 8. Here, an example configuration in which a tension spring is used as the pressure member 17 is shown. Also, similar to the method shown in Fig. 4, each holding member 8 is connected to a support member by a connecting member 14, thereby positioning the contact body 4 in the z direction, and each vibrating body 1 and holding member 8 are slidable in the z direction. Here, a protrusion 2a provided on the vibrating body 1 serves to receive the reaction force.

[0060] Meanwhile, a viscoelastic body 6e is attached to the contact body 4. The y-direction dimension of the viscoelastic body 6e is L5, and a window portion is provided so that the sliding surface of the contact body 4 is exposed within the inner section L6. That is, the viscoelastic body 6e is in close contact with the two side surfaces parallel to the yz plane of the contact body 4 within the inner section L6, and is attached so as to cover the two side surfaces parallel to the yz plane and the surface parallel to the xy plane of the contact body in other regions. The region indicated by L5-L6 where the viscoelastic body 6e covers the four surfaces of the long, rectangular column-shaped contact body 4 preferably includes the portion corresponding to the antinode of the out-of-plane vibration mode excited in the contact body, as described in FIG. 3.

[0061] 4, the contact body unit, which is made up of the contact body 4 and the viscoelastic body 6e, is supported by the support member 15 in a state in which it can move in the y direction by thrust from the vibrators 1 that the vibrator unit 21 has. Specifically, four rollers that can rotate around axes parallel to the z axis are provided on the support member 15 as contact body support parts 12 that movably support the contact body unit. The four contact body support parts 12 act as linear guides that enable movement of the contact body unit in the y direction by restricting the degree of freedom in the xy plane of the side surface of the viscoelastic body 6e in the region indicated by L6.

[0062] According to the above configuration, the vibration actuator 201 uses a total of four vibrating bodies 1 to support the contact body 4 in the z direction, thereby reducing the number of components such as the reaction force receiving portion 10 and the rotation support portion 9. Additionally, by using the vibrating body unit 21 instead of the reaction force receiving portion 10 and the rotation support portion 9, which do not contribute to thrust, the thrust of the vibration actuator can be increased. By using four vibrating bodies 1, it is possible to obtain four times the thrust compared to a common contact body. Furthermore, by covering most of the portions of the contact body 4 that are not used for frictional sliding with the viscoelastic body 6e, it is possible to enhance the effect of suppressing unnecessary vibrations generated in the contact body 4, thereby preventing the generation of abnormal noise and performance degradation due to unnecessary vibrations. As described above, according to this embodiment, it is possible to provide a vibration actuator that can suppress the generation of unnecessary vibrations and improve the thrust (output) per volume or weight.

[0063] Next, a vibration actuator 202 according to a second embodiment will be described with reference to Fig. 8. Figs. 8(a) and 8(b) are a plan view and a front view, respectively, showing the schematic configuration of the vibration actuator 202. The vibration actuator 202 is an embodiment that includes a vibrating body unit 22 and a contact body 4 that comes into contact with the vibrating body 1 of the vibrating body unit 22, the contact body 4 being fixed to a support member 15, and the vibration body unit 22 moving relative to the support member 15. Furthermore, among the components of the vibration actuator 202, those that correspond to the components described above will be given the same names and symbols, and descriptions of their common functions and configurations will be omitted.

[0064] The vibration actuator 202 includes three vibrating body units 22 and a contact body 4. Of the three vibrating body units, the two in the center and on the right are connected by a connecting portion 14. In the vibration actuator 202, both ends of the contact body 4 are fixed to a support member 15, and three viscoelastic bodies 6g, 6h, and 6i are fitted at the antinode positions of an out-of-plane vibration mode that occurs in the contact body 4 at a frequency close to the drive frequency applied to the vibrating body 1. In the vibrating body unit 22, a spacer 19 with a nonwoven fabric 16 attached is disposed inside a holding portion 18. A hook 19a is provided on the spacer 19, and by hooking the end of the pressure member 17, the pair of opposing vibrating bodies 1 clamp and press the contact body 4. In the vibrating body unit 22, the two vibrating bodies 1 are supported by the holding portion 18 so as to be slidable in the z-direction, and degrees of freedom other than the z-direction are constrained relative to the holding portion 1. As in the previous embodiment, the holding portion 18 is provided with an opening 18a, which functions as a linear guide for moving the vibrating body unit 22 in the y direction.

[0065] Of the three vibrating body units 22, the left vibrating body unit 22 can drive the space L7 between the viscoelastic bodies 6g and 6h in the y direction. Meanwhile, the right-end and central vibrating body units 22 are connected by a connecting portion 14 via a holding portion, and can slide slightly relative to each other in the z direction. In this case, it is desirable that the connecting portion be offset in the x direction so as not to interfere with the contact body 14. The two connected vibrating body unit groups 23 can be connected together to drive the space L8 between the viscoelastic bodies 6h and 6i in the y direction.

[0066] With the above configuration, the vibration actuator 202 can move the vibrating body unit 22 and the vibrating body unit group 23 independently in the y direction. In this case, as shown in Fig. 8(a), by providing openings 15b and 15c in the support member 15, the upper surfaces of the vibrating body unit 22 and the vibrating body unit group 23 can be exposed to the outside, and a driven object can be connected to them.

[0067] According to this embodiment, multiple vibrating body units or vibrating body unit groups can be independently driven via a single contact body. In this case, by fitting a viscoelastic body at the antinode position of the out-of-plane vibration mode of the contact body, it is possible to more effectively suppress unwanted vibrations excited in the contact body.

[0068] Furthermore, by connecting two vibrator units to form a vibrator unit group 23, a total of four vibrators 1 can generate four times the thrust. By connecting the vibrator units 22 so that they can move slightly relative to each other in the z direction, each vibrator follows the contact body in response to deformation in the longitudinal direction (within the yz plane) of the contact body, thereby reducing the variation in the pressure reaction force applied to each vibrator. A vibrator with a relatively small pressure reaction force reduces thrust, while a vibrator with a relatively large pressure reaction force poses the risk of wear due to overload. Therefore, by configuring each vibrator unit group using a connecting portion as in this embodiment, each vibrator can efficiently generate thrust. Furthermore, in this embodiment, when the vibrator unit and the vibrator unit group are driven in the y direction and are subjected to an overload, the viscoelastic material acts as a buffer, preventing the vibrator unit from being damaged by direct collision with the support member or the vibrator unit.

[0069] In this embodiment, in the vibration actuator 201, when the contact body moves relatively, a specific method of suppressing unwanted vibration by attaching the viscoelastic body 6e to the rectangular parallelepiped contact body 4 has been described.

[0070] Furthermore, a more advanced embodiment will be described as a contactor unit 23 combining a contactor 24 and a viscoelastic body 26 as shown in FIG. 9. FIG. 9 shows a schematic configuration of (a) a plan view of the contactor unit 23, (b) a front view of the contactor unit 23, (c) a bottom view of the contactor unit 23, (d) a plan view of the contactor 24, (e) a front view of the contactor 24, and (f) a bottom view of the contactor 24. For simplicity, components other than the contactor, viscoelastic body, contactor support, and vibrator are not shown in FIG. 9, and the pressure support structure of the vibrator against the contactor conforms to the above-described embodiment. In FIG. 9, the contactor unit 23 is composed of a contactor 24 and a viscoelastic body 26. The contactor 24 has four sliding portions 24a protruding in the positive and negative z directions and four guide portions 24b protruding in the positive and negative x directions. Meanwhile, the viscoelastic body 26 has a total of eight windows: four windows 26a cut out in the positive and negative z directions and four windows 26b cut out in the positive and negative x directions. In Fig. 9, the sliding portion 24a of the contact body protrudes from the window 26a of the viscoelastic body, and the guide portion 24b of the contact body protrudes from the window 26b of the viscoelastic body. The sliding portion 24a functions as a friction sliding surface against which the protrusion 2a of the vibrating body 1 is pressed to generate the frictional force required for driving, and the guide portion 24b functions as a linear guide to guide the contact body in the y direction using the four contact body support portions 12.

[0071] Applying the contact body unit 23 to a vibration actuator can be expected to have the following effects. First, by closely adhering the viscoelastic body 26 to the side surfaces of the contact body 24 other than the sliding portion and the guide portion, a higher suppression of unwanted vibrations can be expected. Furthermore, by limiting the area of ​​the sliding portion 24a to the required area, it is possible to reduce the cost of grinding (polishing) to obtain stable frictional sliding characteristics. In addition, because the sliding portion 24a protrudes outward from the viscoelastic body 26, grinding (polishing) of the sliding portion 24a can be easily performed even in the state of the vibration body unit 23 to which the viscoelastic body 26 is attached. On the other hand, by having the guide portion 24b protrude outward from the viscoelastic body 26, it is possible to reduce rolling resistance compared to when the contact body support portion 12 rotates on a viscoelastic body, thereby reducing losses in the vibration actuator. In addition, when an external force is applied to the contact body 4, it is possible to reduce the displacement of the contact body compared to when the contact body support portion 12 directly supports the viscoelastic body 26. That is, in the vibration type actuator, even when the contact body moves relatively, it is possible to configure a highly rigid linear guide.

[0072] In this embodiment, a configuration for improving output per unit volume or weight using multiple vibrators has been described. Next, various configurations applicable to the vibration actuators according to the above-described embodiments will be described, in which a single vibrator unit includes multiple vibrators and the protrusions of each vibrator are supported by contacting a contact body. FIGS. 10(a) to 10(f) are schematic diagrams illustrating the support structure of a contact body using multiple vibrators, and are simply shown as viewed from the y direction, which is the direction of movement of the contact body. Note that coordinate axes are shown only in FIG. 10(f) and are omitted in FIGS. 10(a) to 10(e). Although the nonwoven fabric, spacer, pressure unit, and support unit for the vibrator are not shown in FIGS. 10(a) to 10(f), they can be appropriately selected and used from those described in the above-described embodiments.

[0073] Fig. 10(a) shows a configuration in which two opposing vibrating bodies 1 support a contact body 4, a configuration used, for example, in a vibration actuator 201 (see Fig. 7) or the like. Fig. 10(b) shows a configuration in which a vibrating body 1 is arranged on each of the four side surfaces of a contact body 74 having a rectangular cross section to support the contact body 74. Fig. 10(c) shows a configuration in which the substantially cylindrical side surface (curved surface) of a contact body 75 having a substantially circular cross section is supported by three vibrating bodies 1 arranged at intervals of approximately 120° in the zx plane.

[0074] FIG. 10(d) shows a configuration in which a contact body 76 having a polygonal cross section is supported by three vibrators 1 arranged on each of the three sides of the contact body 76. FIG. 10(e) shows a configuration in which three of the sides of a contact body 77 having a polygonal cross section are supported by vibrators 1 and 81 of different sizes and thrust. FIG. 10(f) shows a configuration in which the substantially cylindrical side of a contact body 75 having a substantially circular cross section is supported by two vibrators 1 and two reaction force receiving portions 10. By selectively using these configurations, contact bodies having various cross-sectional shapes can be appropriately supported by the vibrator. Even in the vibrator and contact body configurations shown in FIG. 10, unnecessary vibrations can be reduced by applying the various viscoelastic body embodiments described above.

[0075] Next, a configuration example in which a displacement detection means is provided in the vibrator unit that constitutes the vibration type actuator according to each of the above embodiments will be described. Fig. 11 is a front view showing a state in which a displacement detection section 84 is attached to the vibrator unit 22. Here, the vibrator unit 22 is taken up, but the displacement detection section 84 can also be mounted on other vibrator units.

[0076] The displacement detection unit 84 has a scale 82 and a detector 83. The scale 82 is attached to the contact body support part 12 provided in the holder 18 at a position where it does not physically interfere with (contact with) the contact body 4 (not shown in FIG. 11 ). The scale 82 rotates together with the roller-shaped contact body support part 12 in accordance with the displacement of the contact body 4. The detector 83 detects the amount of movement of the contact body 4 in the y direction by reading the rotational displacement of the scale 82. The rotational displacement of the scale 82 can be read by irradiating light from a light source part provided in the detector 83 onto the scale 82 and receiving the reflected light with a light receiving part of the detector 83. Based on the amount of movement of the contact body 4 in the y direction output by the detector 83, it is possible to control drive parameters such as the position, speed, and acceleration of the contact body 4.

[0077] Furthermore, various types of displacement detection unit 84 can be used, such as optical, magnetic, or capacitance types. Although the displacement detection unit 84 has been described as being of an optical reflective type here, a transmissive type can also be used in the case of an optical type. Furthermore, instead of the rotary type displacement detection unit 84, a linear type displacement detection unit can be used in which a linear type scale is arranged on the contact body 4 and a detector is arranged on the vibrating body unit. [Example]

[0078] 12 is a diagram illustrating the schematic configuration of an actuator unit 401 according to the third embodiment. Figures 12(a) to 12(d) are a plan view (top view), a side view, a front view, and a perspective view of the actuator unit 401, respectively. Note that, among the components of the actuator unit 401, those corresponding to the components of the vibration-type actuators described above will be given the same names and reference numerals, and a description of the common functions and configurations thereof will be omitted.

[0079] The actuator unit 401 is a package of the vibration actuator 201 using an exterior member 86. That is, in the actuator unit 401, the support member 15 of the vibration actuator 201 is movably fixed to the inner bottom surface of the exterior member 86. The contact body 4 moves in the y direction while penetrating the end surface (zx plane) of the exterior member 86, thereby extracting power from the contact body 4. Therefore, in the actuator unit 401, the contact body 4 and a part of the viscoelastic body 6e of the vibration actuator 201 are exposed from the exterior member 86. Note that the vibrator unit 21 and other components that are covered and invisible by the exterior member 86 are indicated by dashed lines in FIG. 12(c).

[0080] In this way, by packaging the vibration actuator 201 in the exterior member 86 to form the actuator unit 401, the user can grip the exterior member 86 and handle it safely, and the vibration actuator 201 can be protected. Note that although an example in which the vibration actuator 201 is packaged has been shown here, the vibration actuators according to each of the above embodiments can be unitized using the exterior member 86 without exception. The exterior member 86 may be configured integrally with the support member 15, etc. [Example]

[0081] In the following embodiments, examples of applications of the various vibration type actuators described above, that is, various devices (apparatus) incorporating vibration type actuators will be described.

[0082] 13 is a plan view showing a schematic configuration of a device 501 according to the fourth embodiment. The device 501 includes six vibration actuators 102 and a support member 35. The six vibration actuators 102 are fixed to the support member 35 via the support member 15, with the support member 15 serving as a reference position. The support member 35 corresponds to an enlarged version of the support member 15 in the xy plane, and is formed as a single member.

[0083] As in the device 501, it is easy to align and arrange six vibration actuators 102 on a plane. For example, the six vibration actuators 102 can be easily aligned and arranged such that they are spaced a distance d in the y direction from the reference position J of the support member 35, and the distance between adjacent support members 15 in the x direction is a distance e. In this case, the distances between the contact bodies 4 of the vibration actuators 102 adjacent in the x direction can all be the same distance f. The vibrator units 11 of the six vibration actuators 102 may be connected to a single driving component (load) or different driving components (loads).

[0084] Although the device 501 is configured here to include six vibration-type actuators 102, it goes without saying that a device similar to the device 501 can be configured using any number of vibration-type actuators 102. Furthermore, depending on the configuration of the device, the multiple vibration-type actuators can be arranged at any positions on the same plane or on different planes.

[0085] As described above, the vibration actuator 102 of the present invention can suppress unwanted vibrations by setting the width dimension of the contact body 4 in the x direction as narrow as possible and using a viscoelastic body. Therefore, when multiple vibration actuators are arranged in the x direction, as in the device 501, the device can be made smaller. Furthermore, as shown in FIG. 13, further miniaturization is possible by arranging the vibration actuators 102 so that they come into contact with each other. Furthermore, by forming the support members 15 and 35 that make up the vibration actuator 102 as an integrated part and minimizing the x direction dimension of the support members as much as possible within the range where the vibrator unit 11 does not interfere, significant miniaturization is possible. [Example]

[0086] FIG. 14(a) is a plan view showing a schematic configuration of a drive unit 500 according to a fifth embodiment. FIG. 14(b) is a side view showing a schematic configuration of a vibration actuator 201 constituting the drive unit 500. The drive unit 500 includes twelve vibration actuators 201 (see FIG. 7) and a support member 36. The support member 36 is formed as a single columnar member, with the y direction as the axial direction and a cross section perpendicular to the y direction describing an approximately regular dodecagon centered at point K. The twelve vibration actuators 201 are fixed radially to twelve side surfaces (surfaces parallel to the y axis) of the support member 36 corresponding to each side of the approximately regular dodecagon in the zx cross section via the support members 15, with the support member 15 as the reference position. In this way, the drive unit 500 allows multiple contact bodies 4 to be accurately arranged on the circumference of a pitch circle 37 having a diameter g and centered at point K when viewed from the y direction. As in the fourth embodiment, by making the width of the contact body 4 as narrow as possible and suppressing unnecessary vibrations with a viscoelastic body, it is possible to set the diameter g small and reduce the size of the drive unit 500. Furthermore, similarly, by forming the support members 15 and 36 that constitute the vibration actuator 102 as an integrated part, it is possible to achieve significant size reduction.

[0087] In the drive unit 500, the vibration actuators 201 are arranged on all side surfaces of the support member 36, but the vibration actuators 201 can be arranged at any position on any side surface. Also, the support member 36 is not limited to a dodecagonal prism, and can be changed to any polygonal prism. [Example]

[0088] 15 is a plan view showing a schematic configuration of a multi-axis stage 503 according to the sixth embodiment. The multi-axis stage 503 includes a fixed portion 41, an x-stage , a y-stage 43, and an xy-stage .

[0089] The degrees of freedom of the fixed part 41 are constrained in all directions and are immovable. Four actuator units 401 (see FIG. 12) are aligned in the y direction and fixed to the fixed part 41 in a manner similar to that of the device 501 described with reference to FIG. 13. The four contact bodies 4 of the four actuator units 401 fixed to the fixed part 41 are movable in the x direction in FIG. 15, and the right ends of each are fixed to the x stage 42.

[0090] The x-stage 42 is movable only in the x-direction, with its degrees of freedom constrained in other directions, and is driven in the x-direction by four actuator units 401 fixed to a fixed portion 41. Two actuator units 401 are fixed to the x-stage 42 and aligned in the x-direction. The two contact bodies 4 of the two actuator units 401 fixed to the x-stage 42 are movable in the y-direction in FIG. 15, and their upper ends are fixed to the y-stage 43.

[0091] The y-stage 43 is movable only in the y-direction, with its degrees of freedom in other directions restricted, and is driven in the y-direction by two actuator units 401 fixed to the x-stage 42. An xy-stage 44 is fixed to the y-stage 43. In conjunction with the movement of the x-stage 42 and / or y-stage 43, the xy-stage 44 moves within the xy plane.

[0092] The mass moved by the actuator unit 401 provided on the fixed part 41 is greater than the mass moved by the actuator unit 401 provided on the x-stage 42. Taking this into consideration, the number of actuator units 401 provided on the fixed part 41 and the x-stage 42 may be set according to the mass of the object to be moved. Although the multi-axis stage 503 is configured as an xy stage with two degrees of freedom, a stage with any number of degrees of freedom can be realized by using multiple actuator units 401.

[0093] The multi-axis stage 503 is configured to move the object to be driven in a predetermined direction using multiple actuator units 401, thereby suppressing the generation of moments in a plane parallel to the xy plane, thereby enabling the xy stage 44 to be moved accurately in the xy plane.

[0094] Similarly, in this embodiment, the width dimension of the contact body 4 in the x direction is set as narrow as possible, and unnecessary vibrations are suppressed by the viscoelastic body, thereby making it possible to reduce the size of the stages 41 and 42. [Example]

[0095] 16 is a plan view showing a schematic configuration of an articulated robot 505 according to a seventh embodiment. The articulated robot 505 is an example of an articulated robot that employs an antagonistic drive system. The articulated robot 505 includes a first joint 52, a fixed portion 54, a first pulley 55, a first link 56, a second link 57, a second joint 58, a second pulley 59, a third pulley 60, a wire 51e, and a wire 53e. In the following description, in order to distinguish between the multiple actuator units 401 provided on the fixed portion 54, the actuator units 401 are denoted by the symbols E1, F1, E2, and F2, respectively.

[0096] The first joint 52 has a degree of freedom of rotation that allows it to rotate around an axis parallel to the z-axis and centered at point L. The second joint 58 has a degree of freedom of rotation that allows it to rotate around an axis parallel to the z-axis and centered at point M, and is constrained by the movement of the first link 56. The first pulley 55, shown by the dashed line, is constrained to the first link 56 and is provided so as to be rotatable around the first joint 52. The second link 57 is provided so as to be rotatable around the second joint 58 via the second joint 58. The second pulley 59 is constrained to the second link 57. The third pulley 60 is provided so as to be rotatable around the first joint 52.

[0097] The wire 51e is wound around the first pulley 55, with one end connected to the contact body 4 of the actuator unit F1 and the other end connected to the contact body 4 of the actuator unit E1. The wire 53e is wound around the third pulley 60, with one end connected to the contact body 4 of the actuator unit F2 and the other end connected to the contact body 4 of the actuator unit E2. The wire 53a is formed in an endless shape (ring shape) and is stretched over the second pulley 59 and the third pulley 60.

[0098] Actuator units E1 and F1, which are arranged so that the movement direction of the contact body 4 is the y direction in Figure 16, each drive wire 51e in the y direction. When actuator units E1 and F1 generate thrust in the y direction to prevent wire 51e from slackening, a frictional force is generated between wire 51e and first pulley 55 due to the difference in the generated thrust, causing first link 56 to rotate about the first joint. This allows actuator units E1 and F1 to cause displacement of first link 56 at angle θ1 with respect to the x-axis.

[0099] Similarly, actuator units E2 and F2, each of which has a contact body 4 arranged to be movable in the x direction in FIG. 16, drive wire 53e in the x direction. When vibration-type actuators E2 and F2 generate thrust in the x-axis direction to prevent wire 53e from slackening, a frictional force is generated between wire 53e and third pulley 60 due to the difference in the generated thrust. This frictional force causes third pulley 60 to rotate, and second pulley 59 moves in conjunction with wire 53a via endless wire 53a, driving first link 56 and second link 57 around first joint 52 and second joint 58. In other words, actuator units E2 and F2 can cause first link 56 to be displaced by angle θ1 relative to the x axis in FIG. 16, and can cause second link 57 to be displaced by angle θ2 relative to first link 56. At this time, by driving the actuator units E1 and F1 so as to cancel out the displacement of the angle θ1 of the first link 56 caused by the driving of the actuator units E2 and F2, it is possible to cause only the displacement of the angle θ2 of the second link 57.

[0100] In this way, the articulated robot 505 can move the tip N of the second link 57 to a target position in the xy plane by driving the multiple actuator units 401. Then, by performing antagonistic driving while constantly applying tension to the wires 51e and 53e to prevent them from slackening, it is possible to suppress deviations due to rattle around the joints and buckling of the wires 51e and 53e. As a result, it is possible to increase the torsional rigidity around each joint and to position the tip N with high precision.

[0101] Similarly, in this embodiment, the width dimension of the contact body 4 in the x direction is set as narrow as possible, and unnecessary vibrations are suppressed by the viscoelastic body, thereby making it possible to reduce the size of the fixing portion 54. [Example]

[0102] 17 is a plan view showing the schematic configuration of a continuum robot 506 according to the eighth embodiment. The articulated robot 505 according to the seventh embodiment operates using an antagonistic drive system, whereas the continuum robot 506 operates using a drive system that pushes and pulls the wire within a range of thrust that does not cause the wire to buckle.

[0103] The continuum robot 506 includes a base unit 502 and a wire-driven manipulator 504. FIG. 18 is a perspective view showing a schematic configuration of the wire-driven manipulator 504. The wire-driven manipulator 504 is equivalent to, for example, that described in Japanese Patent Application Laid-Open No. 2018-140101. The wire-driven manipulator 504 has an intermediate unit 61 and two curved units 66a and 66b. The linear member 62 can change the curvature of the curved units 66a and 66b by sliding the linear member 62 through the hollow portion of the guide tube 65 provided in the intermediate unit 61 without buckling. Note that the intermediate unit 61 may be made of a flexible member, as shown in FIG. 17.

[0104] In the wire-driven manipulator 504, three linear members 62 are provided for each bending portion. Specifically, of the six linear members 62, the tips of three linear members are fixed to guide member tip member 63a and one is fixed to guide member 64a, and the curvature of bending portion 66a is changed by driving the other two linear members. Similarly, the tips of the remaining three linear members 62 are fixed to tip member 63b, and one of the linear members is fixed to guide member 64b, and the curvature of bending portion 66b is changed by driving the other two linear members.

[0105] In the continuum robot 506, a drive unit 500 is mounted on a base 502 as a drive source for a wire-driven manipulator 504 (see FIG. 14). The contact bodies 4 of the vibration actuator 201 housed in the base 502 are respectively coupled to linear members 62 and are used as drive sources for changing the curvatures of the bending portions 66a and 66b of the wire-driven manipulator 504. Note that, similar to the configuration described with reference to FIG. 12, the base 502 is preferably packaged using an exterior member, which makes it possible to adequately protect the internal components and improve operability.

[0106] In the continuum robot 506, the wire-driven manipulator 504 is driven by a drive unit 500 mounted on a base 502, enabling highly accurate control of the curvature of the bending portions 66a, 66b. Furthermore, by using the base 502 for the drive unit that drives the wire-driven manipulator 504, the drive unit can be made smaller and lighter, improving operability. Furthermore, by increasing or decreasing the number of vibrating body units in the base 502, it is possible to easily accommodate the output required for the bending portions 66a, 66b. Additionally, by using a direct-drive vibration actuator to drive the linear member 62 of the wire-driven manipulator 504, responsiveness can be improved compared to when a drive means combining an electromagnetic motor and a reduction mechanism is used.

[0107] The output from each of the vibration actuators 201 housed in the base 502 can be easily changed by increasing or decreasing the number of vibrating body units 20. Furthermore, the magnitude of the thrust and driving speed for driving (bending) the bending portions 66a, 66b can be controlled by changing the amplitude ratio of the vibrations of the multiple vibration modes excited in the vibrating body 1. When no voltage is applied to the electromechanical energy conversion element 3, the static friction force acting between the protrusion 2a and the contact body 4 can maintain the posture of the bending portions 66a, 66b.

[0108] Furthermore, the vibration body 1 can be driven only in the second vibration mode ( FIG. 2(b) ) to change the frictional force acting between the protrusion 2a and the contact body 4. When an external force acts on the curved portions 66a, 66b, the posture of the curved portions 66a, 66b can be changed in response to the external force. This function can be used, for example, as a safety mechanism when using a continuum robot for medical purposes. In this way, when the vibration body 1 is driven only in the second vibration mode ( FIG. 2(b) ) to significantly reduce the frictional force between the vibration body 1 and the contact body 4, it is necessary to set the vibration amplitude to a large value. Generally, the larger the vibration amplitude, the larger the vibration amplitude of unwanted vibrations, leading to a decrease in output and the generation of loud noise. As described in the above embodiment, by fitting a viscoelastic body into the contact body, unwanted vibrations can be suppressed without increasing the size of the vibration actuator. Therefore, the vibration actuator of the present invention can be used to realize such a safety mechanism.

[0109] The continuum robot 506 can be applied to, for example, industrial endoscopes, medical endoscopes, and surgical instruments such as catheters used in medical procedures such as treatment, biopsy, and examination. The continuum robot 506 has two bending sections 66a and 66b, giving it four degrees of freedom, but the number of bending sections, i.e., the degrees of freedom, can be set arbitrarily. 66b is the distal bending section, and 66a is the following bending section.

[0110] In this case, the shape of the support member 36 relative to the base portion 502, the diameter g of the pitch circle 37, and the number and arrangement of the vibration type actuators 201 may be set to appropriate conditions depending on the number of curved portions and the diameter of the guide member.

[0111] For example, in the above embodiments, the connection object connected to the vibrating body unit by the connection portion is another vibrating body unit or a support member, but is not limited to these and may be any part or component that can move relative to the contact body. Furthermore, although the multi-axis stage 503 and the articulated robots 505 and 506 are given as examples of devices to which the vibration actuator and actuator unit according to the above embodiments are applied, examples of applicable devices are not limited to these. For example, other examples of devices according to the present invention include various stage devices such as microscopes, machine tools, and measuring devices, as well as vertical articulated robots and parallel link robots that have more degrees of freedom than the articulated robot 505.

[0112] While the present invention has been described in detail above based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various electronic devices within the scope of the present invention are also included in the present invention. Furthermore, each of the above-described embodiments merely represents one embodiment of the present invention, and each embodiment can be combined as appropriate. [Explanation of symbols]

[0113] 1 vibrating body 4 Contact body 6, 6a-6i, 26 Viscoelastic body 5,11,21,22 Vibration unit 23 Contact unit 7, 13, 17 Pressure section 8,18 Holding part 9 Reaction force receiving part 12 Contact body support part 14 Connection part 15, 35, 36 Support member 86 Exterior materials 101,102,201,202 Vibration actuator 401 Actuator Unit 501,502 equipment 503 Multi-axis stage 505 Articulated Robot 506 Continuum Robot

Claims

1. a vibrating body including an elastic body and an electromechanical energy conversion element; a contact body that contacts the vibrating body, a vibration type actuator in which the vibrating body and the contact body move relatively in a first direction by vibrating the vibrating body, A vibration type actuator, characterized in that an endless viscoelastic body covering a side surface of the contact body is attached to a part of the contact body.

2. 2. The vibration actuator according to claim 1, wherein the total length of the viscoelastic body in the first direction is equal to or greater than half the wavelength of a vibration wave in a natural vibration mode involving out-of-plane vibration excited in the contact body in response to vibration of the vibrating body.

3. a natural vibration mode excited in the vibrating body is an out-of-plane bending vibration mode that generates a plurality of nodal lines in the first direction, 3. The vibration actuator according to claim 1, wherein the total length of the viscoelastic body in the first direction is equal to or greater than the distance between the adjacent nodal lines.

4. The elastic body has a plurality of protrusions, 4. The vibration actuator according to claim 1, wherein the total length of the viscoelastic body in the first direction is equal to or greater than the distance between the centers of the adjacent protrusions.

5. 5. The vibration actuator according to claim 1, wherein the viscoelastic body is provided at both ends of the long contact body.

6. The vibration actuator according to any one of claims 1 to 5, characterized in that the viscoelastic body is provided at a position including an antinode in a natural vibration mode involving out-of-plane vibration excited on the contact body when the viscoelastic body is not provided on the contact body.

7. the viscoelastic body is a member having a hollow hole, When the viscoelastic body is not attached to the contact body, the inner periphery of the hole of the viscoelastic body is 7. The vibration actuator according to claim 1, wherein the length of the contact body is smaller than the total length of the perimeter of the contact body in a cross section perpendicular to the first direction.

8. 8. The vibration actuator according to claim 1, wherein the viscoelastic body has a cutout first window portion, and the vibrating body and the contact body come into contact with each other through the first window portion.

9. the vibration-type actuator includes a contact body support portion that supports the contact body so that the contact body is movable in the predetermined direction, 9. The vibration actuator according to claim 1, wherein the viscoelastic body has a second window portion cut out to expose a guide portion where the contact body and the contact body support portion come into contact.

10. 10. The vibration type actuator according to claim 9, wherein the guide portion is in contact with the contact body through the second window portion.

11. Further comprising a holding portion, the vibrator is held by the holding portion, A vibration actuator according to any one of claims 1 to 10, characterized in that in a cross section of the vibration actuator perpendicular to the first direction, the width dimension of the viscoelastic body is smaller than the width dimension of the vibrating body or the width dimension of the holding portion.

12. The vibration type actuator according to any one of claims 1 to 11, wherein the vibration type actuator comprises a plurality of the vibrating bodies, and the vibrating bodies are moved in the first direction relative to a common contact body to which the viscoelastic body is attached.

13. 13. The vibration actuator according to claim 1, wherein the viscoelastic body is made of a rubber material.

14. 14. The vibration actuator according to claim 1, wherein an endless viscoelastic body is attached to a part of the contact body to cover a side surface of the contact body.

15. 15. The vibration actuator according to claim 14, wherein the viscoelastic body has a window portion cut out so that a part of the contact body is exposed.

16. 16. The vibration actuator according to claim 15, wherein a part of the contact body protrudes from the window portion.

17. a vibration type actuator according to any one of claims 1 to 16; an exterior member that houses a part of the vibration type actuator therein, The actuator unit has a contact body of the vibration type actuator that is partially exposed to the outside of the exterior member.

18. a vibration type actuator according to any one of claims 1 to 16; a component driven by the vibration actuator; An electronic device comprising:

19. The electronic device according to claim 18 , wherein a plurality of the vibration type actuators are arranged radially in a cross section perpendicular to the first direction.

20. a vibration type actuator according to any one of claims 1 to 16; a fixing portion to which the vibration type actuator is fixed; a stage connected to the contact body and movable relative to the fixed portion in a predetermined direction.

21. 17. An articulated robot comprising the vibration actuator according to claim 1 as a drive source.

22. a wire-driven manipulator; 17. A continuum robot comprising the vibration actuator according to claim 1 as a drive source for the wire-driven manipulator.

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