Piezoelectric drive device

Abstract

A piezoelectric drive device (100) has a first piezoelectric drive unit (PD1) and a second piezoelectric drive unit (PD2) that move a movable member (1). The first piezoelectric drive unit (PD1) has a first contact member (9A) that is fixed to a first piezoelectric element (8A) extending along a first axis (8AX) and is in contact with the outer peripheral surface (1F) of the movable member (1). When viewed along a first longitudinal vibration direction (VD1), the first axis (8AX) is configured to tilt and intersect at an angle θ1 with respect to the X-axis direction. The second piezoelectric drive unit (PD2) has a second contact member (9B) that is fixed to a second piezoelectric element (8B) extending along a second axis (8BX) and is in contact with the outer peripheral surface (1F) of the movable member (1). When viewed along a second longitudinal vibration direction (VD2), the second axis (8BX) is configured to tilt and intersect at an angle θ2 with respect to the X-axis direction.

Description

Piezoelectric Drive

[0001] The present disclosure relates to piezoelectric drives.

[0002] 2. Description of the Related Art Conventionally, a driving device that uses a piezoelectric body to translate a linear member is known (see Patent Document 1).

[0003] Japanese Patent Application Publication No. 8-140376

[0004] However, the above-mentioned driving device can only translate the linear member (movable member) and cannot cause the linear member (movable member) to perform other movements.

[0005] It is therefore desirable to provide a piezoelectric drive that can provide multiple types of motion to a movable member.

[0006] A piezoelectric drive device according to an embodiment of the present disclosure includes a fixed member, a movable member having a cross-sectional outer shape in a substantially circular shape in a cutting plane perpendicular to a translation direction, and a piezoelectric drive unit that moves the movable member at least in the translation direction, wherein the piezoelectric drive unit has a first piezoelectric drive unit and a second piezoelectric drive unit, and the first piezoelectric drive unit has a first piezoelectric element extending along a first axis, and a first contact member that extends along the first axis and is fixed to one surface of the first piezoelectric element that faces the movable member, and that contacts an outer peripheral surface of the movable member at a first position, When viewed along a first longitudinal vibration direction, which is a direction perpendicular to the one surface of the first piezoelectric element, the first axis is configured to intersect at an angle with respect to the translation direction, and the second piezoelectric driving unit has a second piezoelectric element extending along the second axis, and a second contact member that extends along the second axis and is fixed to one surface of the second piezoelectric element that faces the movable member, and that contacts the outer peripheral surface of the movable member at a second position, and when viewed along the second longitudinal vibration direction, which is a direction perpendicular to the one surface of the second piezoelectric element, the second axis is configured to intersect at an angle with respect to the translation direction.

[0007] The piezoelectric drive device described above can cause the movable member to undergo several types of motion.

[0008] 5 is a perspective view of a piezoelectric driving device according to an embodiment of the present disclosure. FIG. 6 is an exploded perspective view of the piezoelectric driving device shown in FIG. 1. FIG. 7 is a more detailed exploded perspective view of the piezoelectric driving device shown in FIG. 1. FIG. 8 is a perspective view of a holding member and a piezoelectric driving unit that constitute the piezoelectric driving device shown in FIG. 1. FIG. 9 is a front view of a movable member, a shaft member, a holding member, a rod-shaped member, a piezoelectric driving unit, and an oscillating member that constitute the piezoelectric driving device shown in FIG. 1. FIG. 11 is a diagram showing a piezoelectric element and a contact member that constitute the piezoelectric driving unit shown in FIG. 5. FIG. 5 is a five-view diagram of a movable member and a piezoelectric driving unit that constitute the piezoelectric driving device shown in FIG. 1. FIG. 6 is an exploded perspective view of another configuration example of a piezoelectric driving device according to an embodiment of the present disclosure. FIG. 7 is a diagram of a rod-shaped member and an oscillating member that constitute the piezoelectric driving device shown in FIG. 8. FIG. 7 is a front view of a movable member, a shaft member, a holding member, a rod-shaped member, a piezoelectric driving unit, and an oscillating member that constitute the piezoelectric driving device shown in FIG. 8. FIG. 8 is a diagram showing the positional relationship between a movable member and a piezoelectric driving unit in yet another configuration example of a piezoelectric driving device according to an embodiment of the present disclosure.

[0009] A piezoelectric driving device 100 according to an embodiment of the present disclosure will be described below with reference to FIGS. 1 to 3. FIG. 1 is a perspective view of the piezoelectric driving device 100. Specifically, the upper view of FIG. 1 is a perspective view of the piezoelectric driving device 100 rotating a movable member 1 around a rotation axis 1X. The central view of FIG. 1 is a perspective view of the piezoelectric driving device 100 translating the movable member 1 to one side (X1 side, front side) along the rotation axis 1X. The lower view of FIG. 1 is a perspective view of the piezoelectric driving device 100 translating the movable member 1 to the other side (X2 side, rear side) along the rotation axis 1X. FIG. 2 is an exploded perspective view of the piezoelectric driving device 100, and FIG. 3 is a more detailed exploded perspective view of the piezoelectric driving device 100.

[0010] In FIG. 1 , X1 represents one direction of the X axis that constitutes a three-dimensional Cartesian coordinate system, and X2 represents the other direction of the X axis. Y1 represents one direction of the Y axis that constitutes a three-dimensional Cartesian coordinate system, and Y2 represents the other direction of the Y axis. Z1 represents one direction of the Z axis that constitutes a three-dimensional Cartesian coordinate system, and Z2 represents the other direction of the Z axis. In FIG. 1 , the X1 side of the piezoelectric driving device 100 corresponds to the front side (front face) of the piezoelectric driving device 100, and the X2 side of the piezoelectric driving device 100 corresponds to the rear side (back face) of the piezoelectric driving device 100. The Y1 side of the piezoelectric driving device 100 corresponds to the left side of the piezoelectric driving device 100, and the Y2 side of the piezoelectric driving device 100 corresponds to the right side of the piezoelectric driving device 100. The Z1 side of the piezoelectric driving device 100 corresponds to the top side of the piezoelectric driving device 100, and the Z2 side of the piezoelectric driving device 100 corresponds to the bottom side of the piezoelectric driving device 100. This is similar in other figures.

[0011] The piezoelectric driving device 100 is a device for separately realizing multiple types of motion of the movable member 1, and is configured to include the movable member 1, a fixed member FB, a piezoelectric driving unit PD, and a swinging member SM. In the illustrated example, the multiple types of motion of the movable member 1 include rotation of the movable member 1 around the rotation axis 1X and translation of the movable member 1 along the rotation axis 1X. As shown in the upper diagram of FIG. 1 , the piezoelectric driving device 100 can rotate the movable member 1 around the rotation axis 1X without translating the movable member 1 along the rotation axis 1X. Alternatively, as shown in the center and bottom diagrams of FIG. 1 , the piezoelectric driving device 100 can translate the movable member 1 along the rotation axis 1X without rotating the movable member 1 around the rotation axis 1X. Note that the piezoelectric driving device 100 can also translate the movable member 1 along the rotation axis 1X while rotating the movable member 1 around the rotation axis 1X.

[0012] The movable member 1 is a member moved by the piezoelectric drive unit PD and is configured so that the outer shape of a cross section perpendicular to the rotation axis 1X includes a substantially arc shape. The movable member 1 is made of a metal such as titanium copper or stainless steel. The movable member 1 may also be made of other metals. The other metals may be either magnetic or non-magnetic metals. The movable member 1 may also be made of materials other than metals, such as synthetic resin or ceramic. In the illustrated example, the movable member 1 is a cylindrical body whose outer shape of a cross section perpendicular to the rotation axis 1X is substantially circular, and is configured to move by receiving a driving force generated by the piezoelectric drive unit PD. The movable member 1 may also be a cylindrical body.

[0013] The fixed member FB is a member for supporting the movable member 1 and the swinging member SM. In the illustrated example, the fixed member FB includes a base member 2, a shaft support member 3, a shaft member 4, and a rod-shaped member 11, as shown in FIG.

[0014] The base member 2 is a member for supporting the other members constituting the fixed-side member FB. In the illustrated example, the base member 2 is a member having an approximately rectangular parallelepiped outer shape, and has a through-hole 2K that is rectangular in top view for accommodating the swingable member SM so that it can swing. In the illustrated example, the base member 2 is made of synthetic resin. However, the base member 2 may also be made of metal. In addition, grooves 2G that accommodate both ends of the rod-shaped member 11 are formed on the upper surface of the base member 2.

[0015] The shaft support members 3 are members for supporting the shaft member 4. In the illustrated example, the shaft support members 3 include a rear shaft support member 3B and a front shaft support member 3F. Each of the rear shaft support member 3B and the front shaft support member 3F has a through-hole TH1 through which the cylindrical (round bar-shaped) shaft member 4 is inserted, and is fixed to the upper surface of the base member 2 with an adhesive.

[0016] The shaft member 4 is a member for movably supporting the movable member 1. In the illustrated example, the shaft member 4 is a cylindrical (round bar) member, and is configured to support the movable member 1 rotatably around the rotation axis 1X and to be able to translate along the rotation axis 1X. In the illustrated example, the shaft member 4 is fixed to the shaft support member 3 with an adhesive.

[0017] The rod-shaped member 11 is a member for supporting the oscillating member SM so that it can oscillate. In the illustrated example, the rod-shaped member 11 is made of metal, and is configured so that one end and the other end are fitted into grooves 2G formed in the base member 2, and the middle portion is inserted into a through-hole TH2 provided in the oscillating member SM. The rod-shaped member 11 is fixed to the base member 2 with an adhesive.

[0018] The piezoelectric driving unit PD is a driving mechanism for moving the movable member 1, and as shown in FIG. 3, includes a first piezoelectric driving unit PD1 and a second piezoelectric driving unit PD2.

[0019] The oscillating member SM is a member that enables each of the pair of piezoelectric drive units PD (first piezoelectric drive unit PD1 and second piezoelectric drive unit PD2) to be pressed against the movable member 1. In the illustrated example, as shown in FIG. 3 , the oscillating member SM includes a support member 5, a holding member 6, a biasing member 7, and an intermediate member 12, and is supported by a fixed-side member FB (rod-shaped member 11) so as to be able to oscillate. The oscillating member SM is configured so as to be able to press each of the pair of piezoelectric drive units PD against the movable member 1 with approximately the same force.

[0020] The support member 5 is a member for supporting the piezoelectric drive unit PD. In the illustrated example, the support member 5 includes a first support member 5A for supporting the first piezoelectric drive unit PD1 and a second support member 5B for supporting the second piezoelectric drive unit PD2. The first support member 5A and the second support member 5B have the same size and are arranged symmetrically to each other. Specifically, the first support member 5A has a first opposing portion OP1 that faces the movable member 1 and a first spring bearing portion SR1 that contacts the biasing member 7. Similarly, the second support member 5B has a second opposing portion OP2 that faces the movable member 1 and a second spring bearing portion SR2 that contacts the biasing member 7.

[0021] The holding member 6 is a member for holding the piezoelectric drive unit PD. In the illustrated example, the holding member 6 is formed by pressing a titanium copper metal plate. The metal plate may be formed of other metals such as stainless steel. In the illustrated example, the holding member 6 includes a first holding member 6A for holding the first piezoelectric drive unit PD1 and a second holding member 6B for holding the second piezoelectric drive unit PD2. Specifically, the first holding member 6A is housed in a first recess RP1 formed in the first support member 5A and fixed thereto with an adhesive, and the second holding member 6B is housed in a second recess RP2 (not visible in FIG. 3 ) formed in the second support member 5B and fixed thereto with an adhesive. That is, the first piezoelectric drive unit PD1 is supported by the first support member 5A via the first holding member 6A, and the second piezoelectric drive unit PD2 is supported by the second support member 5B via the second holding member 6B.

[0022] The biasing member 7 is a member that generates a biasing force for pressing the piezoelectric driver PD against the movable member 1. In the illustrated example, the biasing member 7 is a metal leaf spring LS, and the upper surface of the left end is fixed to the lower surface of the first support member 5A, the upper surface of the right end is fixed to the lower surface of the second support member 5B, and the upper surface of an intermediate portion between the left and right ends is fixed to the lower surface of the intermediate member 12. Note that the biasing member 7 can be fixed to each of the support member 5 and the intermediate member 12 by any method, such as adhesive or caulking.

[0023] Specifically, the biasing member 7 is configured to generate a preload that tends to bring the first opposing portion OP1 of the first support member 5A and the second opposing portion OP2 of the second support member 5B closer to each other when the movable member 1 is sandwiched between the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2.

[0024] The intermediate member 12 is a member for forming the through portion TH2 through which the rod-shaped member 11 is inserted. In the illustrated example, the intermediate member 12 is fixed to the upper surface of the intermediate portion of the biasing member 7 while being disposed between the first support member 5A and the second support member 5B so as not to come into contact with either the first support member 5A or the second support member 5B. Specifically, the intermediate member 12 is configured to include a first intermediate member 12A and a second intermediate member 12B, and is configured to sandwich the rod-shaped member 11 between the first intermediate member 12A and the second intermediate member 12B from above and below. The first intermediate member 12A and the second intermediate member 12B are fixed together with an adhesive.

[0025] With this configuration, the oscillating member SM can balance the force pressing the first piezoelectric drive unit PD1 against the movable member 1 and the force pressing the second piezoelectric drive unit PD2 against the movable member 1. In other words, the oscillating member SM can press each of the pair of piezoelectric drive units PD against the movable member 1 with approximately the same force.

[0026] Next, the details of the piezoelectric driver PD will be described with reference to Figures 4 and 5. Figure 4 is a perspective view of the holding member 6 and the piezoelectric driver PD. Specifically, the upper view of Figure 4 is an assembled perspective view, and the lower view of Figure 4 is an exploded perspective view. Figure 5 is a front view of the movable member 1, shaft member 4, holding member 6, rod-shaped member 11, piezoelectric driver PD, and oscillating member SM. Specifically, the upper view of Figure 5 is an assembled view, and the lower view of Figure 5 is an exploded view.

[0027] The piezoelectric driving unit PD is configured to be able to move the movable member 1. In the illustrated example, the piezoelectric driving unit PD is an example of a friction driving unit that uses the driving system disclosed in U.S. Patent No. 7,786,648, and is configured to include a piezoelectric element 8, a contact member 9, and a flexible wiring board 10. The piezoelectric driving unit PD is also configured to be biased by a biasing member 7 and pressed against the movable member 1.

[0028] Specifically, the piezoelectric driver PD includes a first piezoelectric driver PD1 and a second piezoelectric driver PD2, the piezoelectric element 8 includes a first piezoelectric element 8A and a second piezoelectric element 8B, the contact member 9 includes a first contact member 9A and a second contact member 9B, and the flexible wiring board 10 includes a first flexible wiring board 10A and a second flexible wiring board 10B. The flexible wiring board 10 may be replaced with a rigid wiring board. The first flexible wiring board 10A and the second flexible wiring board 10B may also be formed by a common flexible wiring board. In this case, the common flexible wiring board may be configured such that a portion of the board functions as the first flexible wiring board 10A and another portion functions as the second flexible wiring board 10B.

[0029] More specifically, the first piezoelectric drive unit PD1 includes a first piezoelectric element 8A, a first contact member 9A, and a first flexible wiring board 10A, and is held by a first holding member 6A fixed to the first support member 5A, and is biased by a first biasing member 7A fixed to the first support member 5A and pressed against the movable member 1. The second piezoelectric drive unit PD2 includes a second piezoelectric element 8B, a second contact member 9B, and a second flexible wiring board 10B, and is held by a second holding member 6B fixed to the second support member 5B, and is biased by a second biasing member 7B fixed to the second support member 5B and pressed against the movable member 1. The first biasing member 7A and the second biasing member 7B are formed by a common spring member SP (leaf spring LS).

[0030] Each of the first piezoelectric element 8A and the second piezoelectric element 8B is configured to realize bending vibration in response to an applied voltage. In the illustrated example, as shown in the upper diagram of FIG. 4 , the first piezoelectric element 8A extends along a first axis 8AX, and the second piezoelectric element 8B extends along a second axis 8BX. Furthermore, each of the first piezoelectric element 8A and the second piezoelectric element 8B is configured to realize bending vibration having two nodes (nodes ND), as shown in the lower diagram of FIG. 4 . When bending vibration occurs, the two nodes ND hardly vibrate. In the lower diagram of FIG. 4 , for clarity, the positions of the nodes ND on each of the first piezoelectric element 8A and the second piezoelectric element 8B are indicated by a cross pattern. The positions of the nodes ND on the piezoelectric element 8 include the positions of a first node ND1 and a second node ND2. The positions of the nodes ND correspond to positions at a predetermined distance from the end of the piezoelectric element 8. The predetermined distance is, for example, approximately one-quarter of the total length of the piezoelectric element 8.

[0031] The first flexible wiring board 10A is a flexible wiring board including a conductive pattern and is configured to electrically connect an external voltage supply source (control circuit) and the first piezoelectric element 8A. In the illustrated example, the first flexible wiring board 10A is configured to apply a voltage to the first piezoelectric element 8A. The first piezoelectric element 8A is bonded to one surface (proximal side, Y2 side) of the first flexible wiring board 10A with an adhesive. In the illustrated example, the first piezoelectric element 8A has electrodes ED at each of the four corners of the other surface (distal side, Y1 side) of the first flexible wiring board 10A, as shown in FIG. 6 . The four electrodes ED of the first piezoelectric element 8A are bonded to four conductive patterns PT formed on the surface of one surface (proximal side, Y2 side) of the first flexible wiring board 10A with an adhesive. The proximal side refers to the side closer to the movable member 1, and the distal side refers to the side farther from the movable member 1.

[0032] The second flexible wiring board 10B is a flexible wiring board including a conductive pattern and is configured to electrically connect an external voltage supply source (control circuit) to the second piezoelectric element 8B. In the illustrated example, the second flexible wiring board 10B is configured to apply a voltage to the second piezoelectric element 8B. The second piezoelectric element 8B is bonded to one surface (proximal side, Y1 side) of the second flexible wiring board 10B with an adhesive. In the illustrated example, the second piezoelectric element 8B has electrodes ED at each of the four corners of the other surface (distal side, Y2 side). The four electrodes ED of the second piezoelectric element 8B are bonded to four conductive patterns PT formed on the one surface (proximal side, Y1 side) of the second flexible wiring board 10B with an adhesive.

[0033] In the illustrated example, the adhesive is an adhesive capable of forming an anisotropic conductive film, and is heated and pressurized while disposed between the piezoelectric element 8 and the flexible wiring board 10, thereby fixing the adhesive to both the piezoelectric element 8 and the flexible wiring board 10. This electrically connects the four electrodes ED of the piezoelectric element 8 to the four conductive patterns PT, which are part of the conductive pattern of the flexible wiring board 10, individually. However, the adhesive may be a conductive adhesive, or may be replaced with solder or the like.

[0034] In the illustrated example, conductive patterns are formed on both sides of the flexible wiring board 10, and insulating films are provided on both sides to cover the conductive patterns except for the connection portions of the conductive patterns PT, etc. An insulating protective film is provided on the portions that come into contact with the piezoelectric elements 8 and the holding member 6 to ensure more reliable insulation.

[0035] The first piezoelectric driver PD1 is configured to be pressed against the movable member 1 while being held by a first holding member 6A fixed to the first support member 5A. In the illustrated example, the first holding member 6A is configured to contact the surface of the other side (distal side, Y1 side) of the first flexible wiring board 10A at positions (the positions of the first convex portion SG1 and the second convex portion SG2) corresponding to two nodes ND formed during bending vibration of the first piezoelectric element 8A, as shown in Fig. 4. The first holding member 6A and the first flexible wiring board 10A may also be joined by an adhesive.

[0036] The second piezoelectric driver PD2 is configured to be pressed against the movable member 1 while being held by a second holding member 6B fixed to the second support member 5B. In the illustrated example, the second holding member 6B is configured to contact the surface of the other side (distal side, Y2 side) of the second flexible wiring board 10B at positions (the positions of the first convex portion SG1 and the second convex portion SG2) corresponding to two nodes ND formed during bending vibration of the second piezoelectric element 8B, as shown in Fig. 4. The second holding member 6B and the second flexible wiring board 10B may also be joined by an adhesive.

[0037] The holding member 6 is formed from a single metal plate. In the illustrated example, the first holding member 6A has a first fixing portion 6AF fixed to the first support member 5A and a first supporting portion 6AS that supports the first piezoelectric driver PD1. The second holding member 6B has a second fixing portion 6BF fixed to the second support member 5B and a second supporting portion 6BS that supports the second piezoelectric driver PD2.

[0038] The first fixing portion 6AF and the second fixing portion 6BF each include a first protrusion SG1 and a second protrusion SG2 that protrude toward the movable member 1 (proximal side). In the illustrated example, the first protrusion SG1 and the second protrusion SG2 are drawn beads formed by drawing. The first protrusion SG1 and the second protrusion SG2 may also be formed by doweling, half-blanking, or the like. Therefore, recesses corresponding to the first protrusion SG1 and the second protrusion SG2 are formed on the other surface (distal side, Y1 side surface) of the first fixing portion 6AF and the other surface (distal side, Y2 side surface) of the second fixing portion 6BF, respectively. Specifically, the first protrusion SG1 and the second protrusion SG2 are formed to extend (protrude) perpendicular to the extension direction of the piezoelectric element 8. The positions at which the first convex portion SG1 and the second convex portion SG2 are arranged are preferably positions corresponding to the nodes ND of the piezoelectric element 8, and more specifically, are spaced apart from each other in the extension direction of the piezoelectric element 8.

[0039] In the illustrated example, the first piezoelectric drive unit PD1 (first piezoelectric element 8A) is attached to the first holding member 6A so that its long side surfaces are fixed to the first support portion 6AS with an adhesive or the like. Specifically, the first piezoelectric drive unit PD1 is attached to the first holding member 6A so that positions on each of the two long side surfaces corresponding to the first node ND1 and second node ND2 of the first piezoelectric element 8A are fixed to each of the four first support portions 6AS with an adhesive or the like. Furthermore, the first piezoelectric drive unit PD1 is attached to the first holding member 6A so that positions on the first flexible wiring board 10A corresponding to the first node ND1 and second node ND2 of the first piezoelectric element 8A are fixed to each of the first convex portion SG1 and second convex portion SG2 of the first fixing portion 6AF with an adhesive. That is, the first piezoelectric driving unit PD1 is attached to the first holding member 6A so that the portions of the other surface (distal side, Y1 side surface) of the first flexible wiring board 10A that do not correspond to the first node ND1 and second node ND2 of the first piezoelectric element 8A do not come into contact with the first fixed portion 6AF of the first holding member 6A.

[0040] Similarly, the second piezoelectric drive unit PD2 (second piezoelectric element 8B) is attached to the second holding member 6B so that its long side surfaces are fixed to the second support portion 6BS with an adhesive or the like. Specifically, the second piezoelectric drive unit PD2 is attached to the second holding member 6B so that positions on each of its two long side surfaces that correspond to the first node ND1 and second node ND2 of the second piezoelectric element 8B are fixed to the four second support portions 6BS with an adhesive or the like. Furthermore, the second piezoelectric drive unit PD2 is attached to the second holding member 6B so that positions on the second flexible wiring board 10B that correspond to the first node ND1 and second node ND2 of the second piezoelectric element 8B are fixed to the first convex portion SG1 and second convex portion SG2 of the second fixing portion 6BF with an adhesive, respectively. That is, the second piezoelectric driving unit PD2 is attached to the second holding member 6B so that the portions of the other surface (the surface on the Y2 side) of the second flexible wiring board 10B that do not correspond to the first node ND1 and the second node ND2 of the second piezoelectric element 8B do not come into contact with the second fixing portion 6BF of the second holding member 6B.

[0041] Next, the movement of the first piezoelectric drive unit PD1 will be described with reference to FIG. 6 . FIG. 6 is a diagram illustrating the first piezoelectric element 8A and the first contact member 9A that constitute the first piezoelectric drive unit PD1. For clarity, the first flexible wiring substrate 10A is omitted from FIG. 6 . Specifically, the topmost view in FIG. 6 is a perspective view of the first piezoelectric element 8A and the first contact member 9A. The second, third, and fourth views from the top in FIG. 6 are views of the first piezoelectric element 8A and the first contact member 9A as viewed along the first horizontal vibration direction BD1. The fifth, sixth, and seventh views from the top in FIG. 6 are views of the first piezoelectric element 8A and the first contact member 9A as viewed along the first vertical vibration direction VD1. Note that the deflected shape of the first piezoelectric drive unit PD1 is exaggerated in FIG. 6 for ease of understanding. The following description with reference to FIG. 6 relates to the movement of the first piezoelectric drive unit PD1, but is equally applicable to the movement of the second piezoelectric drive unit PD2. This is because the first piezoelectric driving unit PD1 and the second piezoelectric driving unit PD2 have the same configuration.

[0042] In the illustrated example, the first piezoelectric element 8A has two portions (a first portion 8A1 and a second portion 8A2) aligned along the first horizontal vibration direction BD1, and two electrodes ED to which voltages can be applied are formed on each of the two portions. Specifically, a first electrode ED1 and a second electrode ED2 are formed on the first portion 8A1, and a first electrode ED11 and a second electrode ED12 are formed on the second portion 8A2. Note that in FIG. 6, for clarity, a dotted pattern is applied to the first portion 8A1, and a diagonal line pattern is applied to the second portion 8A2.

[0043] When the first piezoelectric driver PD1 applies a voltage to the first portion 8A1 and a voltage to the second portion 8A2 separately at appropriate timing, it can cause the first piezoelectric element 8A to undergo bending vibration (circular motion), for example, so that the locus traced by a center point CP, which is a predetermined point on the first piezoelectric element 8A (first piezoelectric driver PD1), forms a circular orbit centered on the first axis 8AX. The circular motion may also be an elliptical motion. That is, the first piezoelectric element 8A can achieve motion in which the center point CP traces a circle (circular motion). In the illustrated example, the center point CP of the first piezoelectric element 8A is the center of gravity of the first piezoelectric element 8A. However, the center point CP of the circular motion may be located within the first contact member 9A fixed to the first piezoelectric element 8A. This is because the first contact member 9A also performs circular motion together with the first piezoelectric element 8A. Furthermore, by applying voltages to the first portion 8A1 and the second portion 8A2 at appropriate times, the first piezoelectric drive unit PD1 can switch the movement direction (rotation direction) of the center point CP along the circular orbit between clockwise and counterclockwise when viewed from one side along the first axis 8AX. Note that the circle (circular orbit) described by the center point CP does not have to be a perfect circle (true circle), as long as it is approximately circular or may be elliptical. The same applies to the second piezoelectric drive unit PD2.

[0044] By switching the rotation direction in this way, the combination of the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 can switch the translation direction of the movable member 1 along the rotation axis 1X, and can also switch the rotation direction of the movable member 1 around the rotation axis 1X.

[0045] 6, the dashed arrows drawn around the first piezoelectric element 8A represent an example of bending vibration of the first piezoelectric element 8A (circular motion in which the first piezoelectric element 8A rotates counterclockwise around the first axis 8AX while bending). Although not shown by the arrows, the first piezoelectric element 8A can also rotate clockwise around the first axis 8AX while bending.

[0046] The first contact member 9A is attached to the first piezoelectric element 8A and configured to contact the movable member 1. In the illustrated example, the first contact member 9A is bonded to one surface of the first piezoelectric element 8A with an adhesive so as to cover the entire surface of one side (proximal side, Y2 side) of the first piezoelectric element 8A. The first contact member 9A is formed of a metal such as titanium copper or stainless steel and configured with an appropriate thickness so that it can perform bending vibration (circular motion) together with the bending vibration (circular motion) of the first piezoelectric element 8A. In the illustrated example, the first contact member 9A is a friction plate made of stainless steel. The first contact member 9A extends in the same direction as the extension direction of the first piezoelectric element 8A so as to have the same length as the first piezoelectric element 8A. The first contact member 9A is configured to contact the movable member 1 at a center portion in the extension direction. Specifically, the first contact member 9A is configured to contact the movable member 1 at a portion where the amplitude of the bending vibration (circular motion) is maximum (a portion corresponding to the antinode of the bending vibration). In the illustrated example, the first contact member 9A has a contact surface 9AS on the side (proximal side, Y2 side) that comes into contact with the movable member 1, which is a convex curved surface that is convex toward the Y2 side. In other words, the contact surface 9AS is configured to form a surface that has one convex portion.

[0047] The reason for bringing the metal movable member 1 into contact with the metal first contact member 9A is to prevent wear of the movable member 1 due to contact between the synthetic resin movable member 1 and the metal first contact member 9A. Note that, as long as contact between the movable member 1 and the first contact member 9A is achieved, the length of the first contact member 9A in the direction along the first axis 8AX does not have to be the same as the length of the first piezoelectric element 8A in the direction along the first axis 8AX. For example, the length of the first contact member 9A in the direction along the first axis 8AX may be smaller than the length of the first piezoelectric element 8A in the direction along the first axis 8AX. However, it is preferable that the length of the first contact member 9A in the extension direction (direction along the first axis 8AX) be equal to or greater than the length of the first piezoelectric element 8A.

[0048] When the first electrode ED1 is connected to a high potential and the second electrode ED2 is connected to a low potential so that the first portion 8A1 contracts, and when the first electrode ED11 is connected to a high potential and the second electrode ED12 is connected to a low potential so that the second portion 8A2 contracts, the first piezoelectric element 8A and the first contact member 9A each bend so as to become convex on the proximal side, as shown in the second diagram from the top. Hereinafter, the state of the first piezoelectric driver PD1 when the first piezoelectric element 8A and the first contact member 9A each become convex on the proximal side is also referred to as the "proximal convex state."

[0049] Furthermore, when the first electrode ED1 and the second electrode ED2 are connected to the same potential so that the first portion 8A1 does not expand or contract, or when the application of voltage to the first electrode ED1 and the second electrode ED2 is stopped, and when the first electrode ED11 and the second electrode ED12 are connected to the same potential so that the second portion 8A2 does not expand or contract, or when the application of voltage to the first electrode ED11 and the second electrode ED12 is stopped, the first piezoelectric element 8A and the first contact member 9A each extend linearly, as shown in the third and sixth figures from the top. Hereinafter, the state of the first piezoelectric driver PD1 when the first piezoelectric element 8A and the first contact member 9A each extend linearly is also referred to as the "neutral state." The state when the application of voltage is stopped is also referred to as the "initial state."

[0050] Furthermore, when the first electrode ED1 is connected to a low potential and the second electrode ED2 is connected to a high potential so that the first portion 8A1 expands, and when the first electrode ED11 is connected to a low potential and the second electrode ED12 is connected to a high potential so that the second portion 8A2 expands, the first piezoelectric element 8A and the first contact member 9A each bend so as to become convex on the distal side, as shown in the fourth diagram from the top. Hereinafter, the state of the first piezoelectric driver PD1 when the first piezoelectric element 8A and the first contact member 9A each become convex on the distal side is also referred to as the "distal convex state."

[0051] Furthermore, when the first electrode ED1 is connected to a low potential and the second electrode ED2 is connected to a high potential so that the first portion 8A1 expands, and when the first electrode ED11 is connected to a high potential and the second electrode ED12 is connected to a low potential so that the second portion 8A2 contracts, the first piezoelectric element 8A and the first contact member 9A each bend so as to become convex upward in the figure, as shown in the fifth diagram from the top. Hereinafter, the state of the first piezoelectric driver PD1 when the first piezoelectric element 8A and the first contact member 9A each become convex upward in the figure is also referred to as the "upper convex state."

[0052] Furthermore, when the first electrode ED1 is connected to a high potential and the second electrode ED2 is connected to a low potential so that the first portion 8A1 contracts, and when the first electrode ED11 is connected to a low potential and the second electrode ED12 is connected to a high potential so that the second portion 8A2 expands, the first piezoelectric element 8A and the first contact member 9A each bend so as to become convex downward in the figure, as shown in the seventh diagram from the top. Hereinafter, the state of the first piezoelectric driver PD1 when the first piezoelectric element 8A and the first contact member 9A each become convex downward in the figure is also referred to as the "bottom-convex state."

[0053] Furthermore, the operation (vibration) of repeatedly changing the state of the first piezoelectric driver PD1 in the order of a proximal convex state (the state shown in the second diagram from the top), a neutral state (the state shown in the third diagram from the top), a distal convex state (the state shown in the fourth diagram from the top), a neutral state, a proximal convex state, and so on is also referred to as “longitudinal vibration.” Furthermore, the operation (vibration) of repeatedly changing the state of the first piezoelectric driver PD1 in the order of an upper convex state (the state shown in the fifth diagram from the top), a neutral state (the state shown in the sixth diagram from the top), a lower convex state (the state shown in the seventh diagram from the top), a neutral state, an upper convex state, and so on is also referred to as “lateral vibration.”

[0054] When a voltage is applied between the first electrode ED1 (first electrode ED11) and the second electrode ED2 (second electrode ED12) to expand or contract the first portion 8A1 (second portion 8A2) in its extension direction, the first contact member 9A fixed to one surface of the first piezoelectric element 8A does not change dimension in its extension direction. Therefore, the first piezoelectric drive unit PD1 deforms as described above. Furthermore, the first flexible wiring substrate 10A fixed to the other surface of the first piezoelectric element 8A can deform in accordance with the change in shape of the first piezoelectric element 8A.

[0055] Here, the relationship between the bending vibration (circular motion) of the piezoelectric driver PD and the motion of the movable member 1 will be described with reference to Fig. 7. Fig. 7 is a five-view diagram (front view, left side view, right side view, top view, and bottom view) of the movable member 1 and the piezoelectric driver PD. In Fig. 7, the front view is located in the center, the left side view is located to the left of the front view, the right side view is located to the right of the front view, the top view is located above the front view, and the bottom view is located below the front view.

[0056] As shown in the left side view of FIG. 7 , the first piezoelectric driver PD1 generates a force F1 that tends to move the movable member 1 diagonally downward and forward as the state repeatedly changes in the order of a proximal-side convex state, a lower-side convex state, a distal-side convex state, an upper-side convex state, a proximal-side convex state, and so on. Because the movement of the movable member 1 is limited by the shaft member 4 to rotation about the rotation axis 1X and translation along the rotation axis 1X, the force F1 is resolved into an axial component F1X and a rotational component F1Z. Furthermore, the first piezoelectric driver PD1 generates a force F2 that tends to move the movable member 1 diagonally upward and backward as the state repeatedly changes in the order of a proximal-side convex state, an upper-side convex state, a distal-side convex state, a lower-side convex state, a proximal-side convex state, and so on. Because the movement of the movable member 1 is limited by the shaft member 4 to rotation about the rotation axis 1X and translation along the rotation axis 1X, the force F2 is resolved into an axial component F2X and a rotational component F2Z.

[0057] As shown in the right side view of FIG. 7 , the second piezoelectric drive unit PD2 generates a force F3 that tends to move the movable member 1 diagonally downward and forward when the state repeatedly changes in the order of a proximal-side convex state, a lower-side convex state, a distal-side convex state, an upper-side convex state, a proximal-side convex state, etc. Because the movement of the movable member 1 is limited by the shaft member 4 to rotation about the rotation axis 1X and translation along the rotation axis 1X, the force F3 is resolved into an axial component F3X and a rotational component F3Z. Furthermore, the second piezoelectric drive unit PD2 generates a force F4 that tends to move the movable member 1 diagonally upward and backward when the state repeatedly changes in the order of a proximal-side convex state, an upper-side convex state, a distal-side convex state, a lower-side convex state, a proximal-side convex state, etc. Because the movement of the movable member 1 is limited by the shaft member 4 to rotation about the rotation axis 1X and translation along the rotation axis 1X, the force F4 is resolved into an axial component F4X and a rotational component F4Z.

[0058] The piezoelectric drive device 100 can translate the movable member 1 forward (toward X1) as shown by arrow AR1 by synchronizing the movements of the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 and repeatedly changing the states of the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 in the order of proximal convex state, lower convex state, distal convex state, upper convex state, proximal convex state, etc. This is because if the magnitudes of forces F1 and F3 are the same, the rotational component F1Z of force F1 and the rotational component F3Z of force F3, which are opposite to each other, cancel each other out, and the axial component F1X of force F1 and the axial component F3X of force F3, which are in the same direction, are combined.

[0059] Furthermore, the piezoelectric drive device 100 can translate the movable member 1 rearward (toward X2) as shown by arrow AR2 by synchronizing the movements of the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 and repeatedly changing the states of the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 in the order of proximal side convex state, upper side convex state, distal side convex state, lower side convex state, proximal side convex state, etc. This is because if the magnitudes of forces F2 and F4 are the same, the rotational direction component F2Z of force F2 and the rotational direction component F4Z of force F4, which are opposite to each other, cancel each other out, and the axial direction component F2X of force F2 and the axial direction component F4X of force F4, which are in the same direction, are combined.

[0060] Furthermore, the piezoelectric drive device 100 synchronizes the movements of the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2, repeatedly changing the state of the first piezoelectric drive unit PD1 in the order of proximal side convex state, upper side convex state, distal side convex state, lower side convex state, proximal side convex state, etc., and repeatedly changing the state of the second piezoelectric drive unit PD2 in the order of proximal side convex state, lower side convex state, distal side convex state, upper side convex state, proximal side convex state, etc., thereby rotating the movable member 1 around the rotation axis 1X in the clockwise direction as viewed from the X1 side, as indicated by arrow AR3. This is because, if the magnitudes of forces F2 and F3 are the same, the axial component F2X of force F2 and the axial component F3X of force F3, which are opposite in direction, cancel each other out, and the rotational component F2Z of force F2 and the rotational component F3Z of force F3, which are in the same direction, are combined.

[0061] Furthermore, the piezoelectric drive device 100 synchronizes the movements of the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2, repeatedly changing the state of the first piezoelectric drive unit PD1 in the order of proximal side convex state, lower side convex state, distal side convex state, upper side convex state, proximal side convex state, etc., and repeatedly changing the state of the second piezoelectric drive unit PD2 in the order of proximal side convex state, upper side convex state, distal side convex state, lower side convex state, proximal side convex state, etc., thereby rotating the movable member 1 counterclockwise around the rotation axis 1X as viewed from the X1 side, as indicated by arrow AR4. This is because, if the magnitudes of forces F1 and F4 are the same, the axial component F1X of force F1 and the axial component F4X of force F4, which are opposite to each other, cancel each other out, and the rotational component F1Z of force F1 and the rotational component F4Z of force F4, which are in the same direction, are combined.

[0062] In the illustrated example, when viewed along the first longitudinal vibration direction VD1 as shown in the left side view of FIG. 7 , the angle θ1 between the line L3 along the translational direction (X-axis direction) and the line L1 along the first axis 8AX is the same as the angle θ2 between the line L4 along the translational direction (X-axis direction) and the line L2 along the second axis 8BX as shown in the right side view of FIG. 7 . However, the angles θ1 and θ2 may be different from each other. This is because by differentiating the magnitude of the bending vibration (circular motion) of the first piezoelectric drive unit PD1 and the magnitude of the bending vibration (circular motion) of the second piezoelectric drive unit PD2, the resultant force acting in either the rotational direction or the translational direction can be selectively reduced to zero. Specifically, the piezoelectric drive device 100 can reduce the resultant force acting in the rotational direction to zero or the resultant force acting in the translational direction to zero by adjusting the magnitude of the bending vibration (circular motion) of each of the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 using feedback control or the like.

[0063] In the illustrated example, the first piezoelectric driver PD1 is configured so that the first electrode ED1 is connected to a high potential and the second electrode ED2 is connected to a low potential so that the first portion 8A1 contracts, and so that the first electrode ED1 is connected to a low potential and the second electrode ED2 is connected to a high potential so that the first portion 8A1 expands, but it may also be configured so that the first electrode ED1 is connected to a low potential and the second electrode ED2 is connected to a high potential so that the first portion 8A1 contracts, and so that the first electrode ED1 is connected to a high potential and the second electrode ED2 is connected to a low potential so that the first portion 8A1 expands. The same applies to the second portion 8A2.

[0064] Next, with reference to FIGS. 8 to 10, a piezoelectric driving device 100A, which is another configuration example of the piezoelectric driving device 100, will be described. FIG. 8 is an exploded perspective view of the piezoelectric driving device 100A. FIG. 9 is a diagram of the rod-shaped member 11 and oscillating member SM1 that constitute the piezoelectric driving device 100A. Specifically, the top view in FIG. 9 is an assembled top view, the second view from the top in FIG. 9 is an exploded top view, the third view from the top in FIG. 9 is an assembled bottom view, and the bottom view in FIG. 9 is an exploded bottom view. FIG. 10 is a front view of the movable member 1, shaft member 4, holding member 6, rod-shaped member 11, piezoelectric driving unit PD, and oscillating member SM1. Specifically, the top view in FIG. 10 is an assembled view, and the bottom view in FIG. 10 is an exploded view.

[0065] The piezoelectric drive device 100A differs from the piezoelectric drive device 100 having the oscillating member SM in that it has a oscillating member SM1. The oscillating member SM1 differs from the oscillating member SM that uses a leaf spring LS as the urging member 7 (spring member SP) in that it uses a tension coil spring TS as the urging member 7 (spring member SP). The oscillating member SM1 also differs from the oscillating member SM that uses an intermediate member 12 to form the through portion TH2 in that it uses a cover member LM to form the through portion TH2 through which the rod-shaped member 11 is inserted.

[0066] Specifically, the oscillating member SM1 is a member that enables each of the pair of piezoelectric drive units PD (first piezoelectric drive unit PD1 and second piezoelectric drive unit PD2) to be pressed against the movable member 1. In the illustrated example, as shown in FIG. 9 , the oscillating member SM1 includes a support member 5, a holding member 6, a biasing member 7 (tension coil spring TS), and a cover member LM, and is supported by a fixed-side member FB (rod-shaped member 11) so as to be able to oscillate. The oscillating member SM1 is configured so as to be able to press each of the pair of piezoelectric drive units PD against the movable member 1 with approximately the same force.

[0067] More specifically, the support member 5 includes a first support member 5A and a second support member 5B having the same size and shape. The first support member 5A includes a first opposing portion OP1 that faces the movable member 1, a pair of first legs LG1 extending from the first opposing portion OP1, and a first spring bearing portion SR1 disposed between the pair of first legs LG1. The first spring bearing portion SR1 is fixed to the pair of first legs LG1 with an adhesive. Similarly, the second support member 5B includes a second opposing portion OP2 that faces the movable member 1, a pair of second legs LG2 extending from the second opposing portion OP2, and a second spring bearing portion SR2 disposed between the pair of second legs LG2. The second spring bearing portion SR2 is fixed to the pair of second legs LG2 with an adhesive. A first through-portion TH21 is formed on the proximal surface of a pair of first leg portions LG1 of the first support member 5A, and a second through-portion TH22 is formed on the proximal surface of a pair of second leg portions LG2 of the second support member 5B.

[0068] The first support member 5A and the second support member 5B are combined such that one of the pair of second legs LG2 of the second support member 5B is sandwiched between the pair of first legs LG1 of the first support member 5A, and one of the pair of first legs LG1 of the first support member 5A is sandwiched between the pair of second legs LG2 of the second support member 5B. Furthermore, the first support member 5A and the second support member 5B are combined such that the first through portion TH21 and the second through portion TH22 are positioned on the same straight line, and the rod-shaped member 11 is inserted through the through portion TH2 formed by the first through portion TH21 and the second through portion TH22.

[0069] 9, the pair of first lid members LM1 are fixed to the first support member 5A so as to cover the first penetration portion TH21 through which the rod-shaped member 11 is inserted, and the pair of second lid members LM2 are fixed to the second support member 5B so as to cover the second penetration portion TH22 through which the rod-shaped member 11 is inserted. Note that the support member 5 and the lid members LM can be fixed together by any method such as adhesive or caulking.

[0070] The biasing member 7 (tension coil spring TS) includes a first biasing member 7A (first tension coil spring TS1) and a second biasing member 7B (second tension coil spring TS2). The first tension coil spring TS1 and the second tension coil spring TS2 are fixed to the first support member 5A and the second support member 5B, respectively, so as to generate a preload that tends to bring the first opposing portion OP1 of the first support member 5A and the second opposing portion OP2 of the second support member 5B closer to each other. Specifically, as shown in the second drawing from the bottom in FIG. 9 , the left end of the first tension coil spring TS1 is fixed to a second left recess H2L formed in the distal surface of one of the pair of second leg portions LG2 of the second support member 5B, and the right end is fixed to a second right recess H2R formed in the distal surface of the first spring receiving portion SR1 of the first support member 5A. Similarly, the second tension coil spring TS2 has its right end fixed to a first right-side recess H1R formed on the distal surface of one of the pair of first leg portions LG1 of the first support member 5A, and its left end fixed to a first left-side recess H1L formed on the distal surface of the second spring support portion SR2 of the second support member 5B.

[0071] Also, as shown in the top diagram of Figure 9, the first retaining member 6A is accommodated in a first recess RP1 formed in the proximal surface of the first opposing portion OP1 of the first support member 5A and fixed thereto with adhesive, and the second retaining member 6B is accommodated in a second recess RP2 formed in the proximal surface of the second opposing portion OP2 of the second support member 5B and fixed thereto with adhesive.

[0072] With this configuration, similar to the piezoelectric driving device 100, the piezoelectric driving device 100A can rotate the movable member 1 about the rotation axis 1X without translating the movable member 1 along the rotation axis 1X by utilizing the bending vibrations (circular motion) of the first piezoelectric driving unit PD1 and the second piezoelectric driving unit PD2, or can translate the movable member 1 along the rotation axis 1X without rotating the movable member 1 about the rotation axis 1X. Note that the piezoelectric driving device 100A can also translate the movable member 1 along the rotation axis 1X while rotating the movable member 1 about the rotation axis 1X.

[0073] Although the swinging member SM1 is configured to use a tension coil spring TS as the biasing member 7 (spring member SP), it may also be configured to use a compression coil spring as the biasing member 7 (spring member SP). When a compression coil spring is used as the biasing member 7, the position at which the biasing member 7 is disposed may be changed.

[0074] Next, another example of the arrangement of the piezoelectric driver PD will be described with reference to FIG. 11 . FIG. 11 is a diagram showing the positional relationship between the movable member 1 and the piezoelectric driver PD. Specifically, the upper left and upper right views of FIG. 11 show a first half-side arrangement of the piezoelectric driver PD, and the lower left and lower right views of FIG. 11 show a second half-side arrangement of the piezoelectric driver PD. More specifically, the upper left and lower left views of FIG. 11 are front views of the movable member 1 and the piezoelectric driver PD, and the upper right and lower right views of FIG. 11 are right side views of the movable member 1 and the piezoelectric driver PD. Furthermore, in the upper right and lower right views of FIG. 11 , only the outline of the movable member 1 is shown with a thick dotted line for ease of understanding.

[0075] The first one-sided arrangement and the second one-sided arrangement are examples of one-sided arrangement. The one-sided arrangement means that the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 are arranged on one side of the movable member 1, unlike the two-sided arrangement (opposite arrangement) shown in Figures 5 and 10 in which the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 are arranged to face each other across the movable member 1. In the example shown in Figure 11, both the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 are arranged on the left side (Y1 side) of the movable member 1, rather than on the right side (Y2 side) of the movable member 1.

[0076] 11 , in the first one-sided arrangement, the first piezoelectric drive unit PD1 is arranged to contact the outer peripheral surface 1F of the movable member 1 at a first position P1, and the second piezoelectric drive unit PD2 is arranged to contact the outer peripheral surface 1F of the movable member 1 at a second position P2. When viewed from the Y2 side along the Y-axis direction, the first piezoelectric drive unit PD1 is arranged such that a line L1 along the first axis 8AX obliquely intersects with a line L3 along the translation direction (X-axis direction) at an angle θ1 greater than 0 degrees and less than 90 degrees. When viewed from the Y2 side along the Y-axis direction, the second piezoelectric drive unit PD2 is arranged such that a line L2 along the second axis 8BX obliquely intersects with a line L4 along the translation direction (X-axis direction) at an angle θ2 greater than 0 degrees and less than 90 degrees. The first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 are arranged so that the angles θ1 and θ2 are symmetrical (vertically symmetrical) about the rotation axis 1X. That is, as shown in the upper left diagram of FIG. 11 , the angle α1 between the lines AL1 and ALC is the same as the angle α2 between the lines AL2 and ALC. Note that the line AL1 is a line that passes through the first position P1 and the rotation axis 1X in the YZ plane, the line AL2 is a line that passes through the second position P2 and the rotation axis 1X in the YZ plane, and the line ALC is a line that is parallel to the Y axis and intersects with the rotation axis 1X in the YZ plane. However, the angles α1 and α2 may be different from each other.

[0077] Furthermore, in the example shown in the upper left and upper right diagrams of Figure 11, the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 are arranged so that the distance between their left ends in the figure is smaller than the distance between their right ends in the figure, as shown in the upper right diagram of Figure 11, but they may also be arranged so that the distance between their left ends in the figure is greater than the distance between their right ends in the figure.

[0078] 11 , in the second one-sided arrangement, the first piezoelectric drive unit PD1 is arranged to contact the outer peripheral surface 1F of the movable member 1 at a first position P1, and the second piezoelectric drive unit PD2 is arranged to contact the outer peripheral surface 1F of the movable member 1 at a second position P2. When viewed from the Y2 side along the Y-axis direction, the first piezoelectric drive unit PD1 is arranged such that a line L1 along the first axis 8AX obliquely intersects with a line L3 along the translation direction (X-axis direction) at an angle θ1 greater than 0 degrees and less than 90 degrees. When viewed from the Y2 side along the Y-axis direction, the second piezoelectric drive unit PD2 is arranged such that a line L2 along the second axis 8BX obliquely intersects with a line L4 along the translation direction (X-axis direction) at an angle θ2 greater than 0 degrees and less than 90 degrees. The first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 are arranged so that the angles θ1 and θ2 are symmetrical (front-to-back symmetrical) across the straight line AL3, which represents a plane perpendicular to the rotation axis 1X.

[0079] Furthermore, in the example shown in the lower left and lower right diagrams of Figure 11, the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 are arranged so that the distance between the left end of the first piezoelectric drive unit PD1 and the right end of the second piezoelectric drive unit PD2 in the diagram is greater than the distance between the right end of the first piezoelectric drive unit PD1 and the left end of the second piezoelectric drive unit PD2 in the diagram, as shown in the lower right diagram of Figure 11, but they may also be arranged so that the distance between the left end of the first piezoelectric drive unit PD1 and the right end of the second piezoelectric drive unit PD2 in the diagram is smaller than the distance between the right end of the first piezoelectric drive unit PD1 and the left end of the second piezoelectric drive unit PD2 in the diagram.

[0080] 11, even when the piezoelectric drive unit PD is disposed on one side, the piezoelectric drive device 100 can rotate the movable member 1 about the rotation axis 1X without translating the movable member 1 along the rotation axis 1X, as in the case where the piezoelectric drive unit PD is disposed on both sides (opposite arrangement), or can translate the movable member 1 along the rotation axis 1X without rotating the movable member 1 about the rotation axis 1X. Note that the piezoelectric drive device 100 can also translate the movable member 1 along the rotation axis 1X while rotating the movable member 1 about the rotation axis 1X.

[0081] In the single-sided arrangement, the movable member 1 is configured such that its movement is guided by a guide member such as the shaft member 4. That is, the guide member prevents the movable member 1 from moving in any manner other than rotation about the rotation axis 1X and translation along the rotation axis 1X. The biasing member 7 (not shown) is configured in combination with other members as necessary to continuously maintain contact between the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 and the movable member 1. On the other hand, in the double-sided arrangement (opposing arrangement) shown in FIG. 5 , the shaft member 4 functioning as a guide member may be omitted. This is because, in the double-sided arrangement (opposing arrangement) shown in FIG. 5 , the movable member 1 is sandwiched between the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2, limiting movement other than rotation about the rotation axis 1X and translation along the rotation axis 1X.

[0082] As described above, the piezoelectric drive device 100 according to the embodiment of the present disclosure includes a fixed member FB, a movable member 1 having a substantially circular cross-sectional outer shape in a cutting plane perpendicular to the translation direction (X-axis direction), and a piezoelectric drive unit PD that moves the movable member 1 at least in the translation direction (X-axis direction). As shown in FIG. 3 , the piezoelectric drive unit PD includes a first piezoelectric drive unit PD1 and a second piezoelectric drive unit PD2. As shown in FIGS. 4 to 6 , the first piezoelectric drive unit PD1 includes a first piezoelectric element 8A extending along a first axis 8AX, and a first contact member 9A that extends along the first axis 8AX, is overlaid on and fixed to a surface (first plane FP1) of the first piezoelectric element 8A facing the movable member 1 (Y2 side), and is in contact with the outer peripheral surface 1F (see FIG. 5 ) of the movable member 1 at a first position P1. 7, when viewed along a first longitudinal vibration direction VD1 (Y-axis direction) that is a direction perpendicular to one surface (first plane FP1) of the first piezoelectric element 8A (the direction in which the first piezoelectric element 8A and the first contact member 9A are overlapped), a line L1 along the first axis 8AX obliquely intersects with a line L3 along the translation direction (X-axis direction) at an angle θ1 that is greater than 0 degrees and less than 90 degrees. Similarly, the second piezoelectric drive unit PD2 has a second piezoelectric element 8B extending along the second axis 8BX, and a second contact member 9B that extends along the second axis 8BX and is overlapped and fixed to one surface (first plane FP2) of the second piezoelectric element 8B that faces the movable member 1 (Y1 side), and that comes into contact with the outer circumferential surface 1F of the movable member 1 at a second position P2. Furthermore, when viewed along the second longitudinal vibration direction VD2 (Y-axis direction), which is a direction perpendicular to one surface (first plane FP2) of the second piezoelectric element 8B (the direction in which the second piezoelectric element 8B and the second contact member 9B are overlapped), the second piezoelectric drive unit PD2 is disposed so that a line L2 along the second axis 8BX intersects obliquely with a line L4 along the translation direction (X-axis direction) at an angle θ2 greater than 0 degrees and less than 90 degrees. In the example shown in FIG. 5 , a line AL passing through the first position P1 and the second position P2 intersects with the rotation axis 1X. The first piezoelectric drive unit PD1 is disposed so that a line perpendicular to one surface (first plane FP1) of the first piezoelectric element 8A and passing through the first position P1 intersects with the rotation axis 1X.Similarly, the second piezoelectric drive unit PD2 is disposed so that a straight line that is perpendicular to one surface (first plane FP2) of the second piezoelectric element 8B and passes through the second position P2 intersects with the rotation axis 1X.

[0083] In this configuration, the movable member 1 is driven by a first piezoelectric drive unit PD1 that contacts the outer peripheral surface 1F of the movable member 1 at a first position P1 and a second piezoelectric drive unit PD2 that contacts the outer peripheral surface 1F of the movable member 1 at a second position P2. This configuration therefore has the effect of enabling the movable member 1 to perform multiple types of motion by controlling the driving method (movement) of the two piezoelectric drive units PD. This configuration is useful, for example, when used in a humanoid or animal-type robot, manipulator, or the like. In the illustrated example, the multiple types of motion include rotation around a rotation axis 1X (X-axis) and translation along the rotation axis 1X (X-axis).

[0084] 6, the first piezoelectric element 8A may have two portions (a first portion 8A1 and a second portion 8A2) aligned along a first horizontal vibration direction BD1 that is perpendicular to the first axis 8AX and perpendicular to the first longitudinal vibration direction VD1, and two electrodes ED may be formed on each of the two portions so that voltages can be applied separately. Similarly, the second piezoelectric element 8B may have two portions aligned along a second horizontal vibration direction BD2 that is perpendicular to the second axis 8BX and perpendicular to the second longitudinal vibration direction VD2, and two electrodes ED may be formed on each of the two portions so that voltages can be applied separately.

[0085] This configuration enables circular motion (including elliptical motion) of the piezoelectric drive unit PD to be realized by applying voltage to the piezoelectric element 8 at the appropriate timing, thereby providing the effect of selectively realizing translation of the movable member 1 along the rotation axis 1X and rotation of the movable member 1 around the rotation axis 1X.

[0086] A first flexible wiring board 10A having a conductive pattern PT connected to the electrode ED may be fixed to the other surface (second plane DP1) (Y1 side) of the first piezoelectric element 8A. Similarly, a second flexible wiring board 10B having a conductive pattern PT connected to the electrode ED may be fixed to the other surface (second plane DP2) (Y2 side) of the second piezoelectric element 8B. In other words, the first piezoelectric drive unit PD1 may have a first flexible wiring board 10A fixed to the other surface (second plane DP1) of the first piezoelectric element 8A and having a conductive pattern PT connected to the electrode ED of the first piezoelectric element 8A. The second piezoelectric drive unit PD2 may have a second flexible wiring board 10B fixed to the other surface (second plane DP2) of the second piezoelectric element 8B and having a conductive pattern PT connected to the electrode ED of the second piezoelectric element 8B.

[0087] This configuration has the effect of making it easier to pass electricity through the piezoelectric element 8 compared to when a conductive pattern is formed on the support member 5 or the like.

[0088] Furthermore, as shown in FIG. 5, the piezoelectric driving device 100 may have a first biasing member 7A that biases the first contact member 9A toward the movable member 1 and brings the first contact member 9A into contact with the movable member 1, and a second biasing member 7B that biases the second contact member 9B toward the movable member 1 and brings the second contact member 9B into contact with the movable member 1.

[0089] This configuration brings about the effect that the movable member 1 can be moved more reliably compared to a configuration in which the contact member 9 presses the movable member 1 weakly.

[0090] Furthermore, the first biasing member 7A and the second biasing member 7B may be configured by a common spring member SP.

[0091] This configuration has the advantage of being able to suppress an increase in the number of parts compared to when the first biasing member 7A and the second biasing member 7B are configured as separate, independent members.

[0092] 5, the piezoelectric driving device 100 may have a first support member 5A including a first opposing portion OP1 that supports the first piezoelectric driving unit PD1 and a second support member 5B including a second opposing portion OP2 that supports the second piezoelectric driving unit PD2. In this case, the first opposing portion OP1 and the second opposing portion OP2 may be disposed on opposite sides of the movable member 1. The spring member SP may be provided between the first support member 5A and the second support member 5B and configured to press (bias) the first contact member 9A toward the movable member 1 (Y2 side) via the first support member 5A and to press (bias) the second contact member 9B toward the movable member 1 (Y1 side) via the second support member 5B.

[0093] This configuration allows the movable member 1 to be sandwiched between the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2, which has the effect of making it easier for the spring member SP to apply a biasing force to each of the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2. Therefore, this configuration has the effect of stabilizing the pressing of the contact member 9 against the movable member 1 and enabling the movable member 1 to be moved more reliably.

[0094] 2 and 3, the piezoelectric driving device 100 may include a rod-shaped member 11 extending in the translation direction (X-axis direction), and an intermediate member 12 having a through-hole TH2 through which the rod-shaped member 11 is inserted and disposed with a gap GP (see FIG. 5) between the first support member 5A and the second support member 5B. Note that the intermediate member 12 may be integrated with one of the first support member 5A and the second support member 5B. 5 , the spring member SP may be formed of a leaf spring LS, with a first portion LS1 of the leaf spring LS fixed to the first support member 5A at a first fixing position CT1 away from a portion (first opposing portion OP1) where the first piezoelectric drive unit PD1 is disposed, a second portion LS2 of the leaf spring LS fixed to the second support member 5B at a second fixing position CT2 away from a portion (second opposing portion OP2) where the second piezoelectric drive unit PD2 is disposed, and a third portion 7C (intermediate portion) located between the first portion LS1 and the second portion LS2 may be fixed to the intermediate member 12. Furthermore, the leaf spring LS may be configured to apply a force such that the portion (first opposing portion OP1) of the first support member 5A where the first piezoelectric drive unit PD1 is disposed and the portion (second opposing portion OP2) of the second support member 5B where the second piezoelectric drive unit PD2 is disposed approach each other.

[0095] This configuration has the effect of making it possible to equalize the force pressing against the first contact member 9A and the movable member 1 and the force pressing against the second contact member 9B and the movable member 1. This is because the swinging member SM swings around the rod-shaped member 11 and holds the first contact member 9A and the second contact member 9B so that the movable member 1 is sandwiched between the first contact member 9A and the second contact member 9B.

[0096] 9, the spring member SP may be formed of a tension coil spring TS. Also, as shown in FIG. 10, when viewed along the translation direction (X-axis direction), the first support member 5A and the second support member 5B may have a portion where they intersect with each other (intersection portion CR). That is, the intersection portion CR may include a first intersection portion CR1 of the first support member 5A and a second intersection portion CR2 of the second support member 5B. Furthermore, at the intersection portion CR, the rod-shaped member 11 may be inserted through the first support member 5A and the second support member 5B. Furthermore, a tension coil spring TS may be arranged between a portion (first leg portion LG1 or first spring receiving portion SR1) located on the opposite side of the portion (first opposing portion OP1) where the first piezoelectric drive unit PD1 is arranged across the first intersection portion CR1 of the first support member 5A, and a portion (second spring receiving portion SR2 or second leg portion LG2) located on the opposite side of the portion (second opposing portion OP2) where the second piezoelectric drive unit PD2 is arranged across the second intersection portion CR2 of the second support member 5B.

[0097] This configuration has the effect of making the force pressing against the first contact member 9A and the movable member 1 the same as the force pressing against the second contact member 9B and the movable member 1, as in the case where the spring member SP is composed of a leaf spring LS as shown in Figure 5.

[0098] In addition, the piezoelectric driving device 100 may have a first holding member 6A that holds the first piezoelectric driving unit PD1 and is formed as a separate member from the first biasing member 7A, and a second holding member 6B that holds the second piezoelectric driving unit PD2 and is formed as a separate member from the second biasing member 7B.

[0099] This configuration has the advantage of allowing for greater freedom in design compared to when the holding member 6 and the biasing member 7 are integrally formed. However, the holding member 6 and the biasing member 7 may also be integrally formed.

[0100] 5, when viewed along the translation direction (X-axis direction), the first position P1 and the second position P2 may be at different positions in the circumferential direction of the movable member 1. In the example shown in Fig. 5, the first position P1 and the second position P2 are arranged to differ from each other by a central angle of 180 degrees about the rotation axis 1X.

[0101] This configuration has the advantage that it is easier to arrange the two piezoelectric drive units PD (to make them contact the movable member 1) than a configuration in which the first position P1 and the second position P2 are arranged so that they differ from each other by a central angle of less than 180 degrees. This is because the direction in which the first contact member 9A is pressed against the movable member 1 and the direction in which the second contact member 9B is pressed against the movable member 1 are opposite to each other. Furthermore, this configuration has the advantage that it is possible to increase the range of motion of the movable member 1 in the translation direction (X-axis direction) compared to the second one-sided arrangement shown in the lower right diagram of FIG.

[0102] As shown in FIG. 5, the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 may be disposed at positions facing each other with the movable member 1 interposed therebetween.

[0103] This configuration has the effect of transmitting movement (force) to the movable member 1 in a well-balanced manner.

[0104] Furthermore, when viewed along the first longitudinal vibration direction VD1 as shown in the left side view of Figure 7, the line L1 along the first axis 8AX with respect to the line L3 along the translation direction (X-axis direction), and when viewed along the second longitudinal vibration direction VD2 as shown in the right side view of Figure 7, the line L2 along the second axis 8BX with respect to the line L4 along the translation direction (X-axis direction), may be inclined in the same direction (towards the same side, that is, the X1 side).

[0105] This configuration can simultaneously realize translation of the movable member 1 along the rotation axis 1X and rotation of the movable member 1 about the rotation axis 1X. This configuration also has the effect of selectively realizing either translation of the movable member 1 along the rotation axis 1X or rotation of the movable member 1 about the rotation axis 1X.

[0106] Furthermore, when viewed along the first longitudinal vibration direction VD1 as shown in the left side view of Figure 7, the angle θ1 between the line L3 along the translation direction (X-axis direction) and the line L1 along the first axis 8AX may be the same as the angle θ2 between the line L4 along the translation direction (X-axis direction) and the line L2 along the second axis 8BX as shown in the right side view of Figure 7 when viewed along the second longitudinal vibration direction VD2.

[0107] This configuration brings about the effect that it is easier to control the movement of the movable member 1 in a desired direction compared to when the angle θ1 and the angle θ2 are different from each other.

[0108] Furthermore, as shown in Figure 10, the first piezoelectric driving unit PD1 and the second piezoelectric driving unit PD2 may be arranged so that one surface (first plane FP1) of the first piezoelectric element 8A and one surface (first plane FP2) of the second piezoelectric element 8B are inclined when viewed along the translation direction (X-axis direction) (so that the first plane FP1 and the first plane FP2 form part of a V-shape).

[0109] This configuration brings about the effect of realizing a smaller size of the piezoelectric driving device 100 compared to the case where the first piezoelectric driving unit PD1 and the second piezoelectric driving unit PD2 are arranged opposite each other as shown in FIG.

[0110] The first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 may be arranged side by side in the translation direction (X-axis direction), as shown in the lower right diagram of FIG. 11 . In this case, when viewed along the first longitudinal vibration direction VD1, the line L1 along the first axis 8AX and the line L2 along the second axis 8BX may be inclined in opposite directions relative to the line L3 along the translation direction (X-axis direction). In the example shown in the lower right diagram of FIG. 11 , the first piezoelectric drive unit PD1 and the second piezoelectric drive unit PD2 are arranged so that the distance between the left end of the first piezoelectric drive unit PD1 and the right end of the second piezoelectric drive unit PD2 is greater than the distance between the right end of the first piezoelectric drive unit PD1 and the left end of the second piezoelectric drive unit PD2.

[0111] This configuration has the advantage of being able to reduce the size of the piezoelectric driving device 100 in the Y-axis direction compared to when the first piezoelectric driving unit PD1 and the second piezoelectric driving unit PD2 are arranged opposite each other as shown in Figure 5 or Figure 10.

[0112] The movable member 1 may also be made of metal, which has the advantage of being able to suppress the generation of wear particles and the like that accompany contact between the movable member 1 and the piezoelectric drive unit PD (contact member 9) compared to when the movable member 1 is made of synthetic resin.

[0113] The movable member 1 may also have a cylindrical shape. In this case, the fixed member FB may include a shaft member 4 that is inserted through the movable member 1.

[0114] This configuration allows the shaft member 4 to function as a guide member, thereby providing the effect of stabilizing the movement of the movable member 1.

[0115] The preferred embodiments of the present disclosure have been described above in detail. However, the present invention is not limited to the above-described embodiments. Various modifications or substitutions may be applied to the above-described embodiments without departing from the scope of the present invention. Furthermore, the features described with reference to the above-described embodiments may be combined as appropriate unless technically inconsistent.

[0116] For example, in the above-described embodiment, the movable member 1 is cylindrical, with the shaft member 4 inserted therethrough and rotating about the shaft member 4, but it may also be rod-shaped (cylindrical) without a through-hole through which the shaft member 4 is inserted. For example, the shaft member 4 may be a part of the movable member 1. In this case, the piezoelectric driving device 100 can rotate the movable member 1, with which the shaft member 4 is integrated, about the rotation axis 1X and translate it along the rotation axis 1X.

[0117] This application claims priority based on Japanese Patent Application No. 2024-027172, filed on February 27, 2024, the entire contents of which are incorporated herein by reference.

[0118] REFERENCE SIGNS LIST 1... Movable member 1F... Outer peripheral surface 1X... Rotating shaft 2... Base member 2G... Groove portion 2K... Through portion 3... Shaft support member 3B... Rear shaft support member 3F... Front shaft support member 4... Shaft member 5... Support member 5A... First support member 5B... Second support member 6... Holding member 6A... First holding member 6AF... First fixed portion 6AS... First support portion 6B... Second holding member 6BF... Second fixed portion 6BS... Second support portion 7... Urging member 7A... First urging member 7B... Second urging member 7C... Third 8... Piezoelectric element 8A... First piezoelectric element 8A1... First portion 8A2... Second portion 8AX... First shaft 8B... Second piezoelectric element 8BX... Second shaft 9... Contact member 9A... First contact member 9AS... Contact surface 9B...Second contact member 10...Flexible wiring board 10A...First flexible wiring board 10B...Second flexible wiring board 11...Rod-shaped member 12...Intermediate member 12A...First intermediate member 12B...Second intermediate member 100, 100A...Piezoelectric drive device BD1...First lateral vibration direction BD2...Second lateral vibration direction CP...Center point CR...Intersection portion CR1...First intersection portion CR2...Second intersection portion CT1...First fixing position CT2...Second fixing position DP1, DP2...Second plane ED...Electrode ED1, ED11...First electrode ED2, ED12...Second electrode FB...Fixed side member FP1, FP2...First plane H1L...First left recess H1R...First right recess H2L...Second left recess H2R...Second right recess LG1...first leg LG2...second leg LM...lid member LM1...first lid member LM2...second lid member LS...leaf spring LS1...first part LS2...second part ND...node ND1...first node ND2...second node OP1...first opposing part OP2...second opposing part P1...first position P2...second position PD...piezoelectric drive part PD1...first piezoelectric drive part PD2...second piezoelectric drive part PT...conductive pattern RP1...first recess RP2...second recess SG1...first convex part SG2...second convex part SM,SM1: Oscillating member SP: Spring member SR1: First spring receiving portion SR2: Second spring receiving portion TH1, TH2: Through portion TH21: First through portion TH22: Second through portion TS: Tension coil spring TS1: First tension coil spring TS2: Second tension coil spring VD1: First vertical vibration direction VD2: Second vertical vibration direction

Claims

1. A piezoelectric drive device comprising: a fixed member; a movable member having a cross-sectional outer shape of a substantially circular shape in a cutting plane perpendicular to a translational direction; and a piezoelectric drive unit that moves the movable member at least in the translational direction, wherein the piezoelectric drive unit has a first piezoelectric drive unit and a second piezoelectric drive unit, the first piezoelectric drive unit having a first piezoelectric element extending along a first axis, and a first contact member that extends along the first axis and is fixed to one surface of the first piezoelectric element facing the movable member, and that comes into contact with the outer surface of the movable member at a first position, when viewed along a first longitudinal vibration direction that is a direction perpendicular to the one surface of the first piezoelectric element, the first axis is configured to intersect at an angle with respect to the translational direction, and the second piezoelectric drive unit has a second piezoelectric element extending along the second axis, and a second contact member that extends along the second axis and is fixed to one surface of the second piezoelectric element facing the movable member, and that comes into contact with the outer surface of the movable member at a second position, When viewed along a second longitudinal vibration direction that is a direction perpendicular to the one surface of the second piezoelectric element, the second axis is configured to intersect at an angle with respect to the translation direction.

2. The piezoelectric drive device described in claim 1, wherein the first piezoelectric element has two parts aligned along a direction perpendicular to the first axis and perpendicular to the first longitudinal vibration direction, and two electrodes are formed on each of the two parts so that a voltage can be applied individually; and the second piezoelectric element has two parts aligned along a direction perpendicular to the second axis and perpendicular to the second longitudinal vibration direction, and two electrodes are formed on each of the two parts so that a voltage can be applied individually.

3. A piezoelectric driving device as described in claim 2, wherein a first flexible wiring board having a conductive pattern connected to the electrode is fixed to the other surface of the first piezoelectric element, and a second flexible wiring board having a conductive pattern connected to the electrode is fixed to the other surface of the second piezoelectric element.

4. A piezoelectric drive device as described in any one of claims 1 to 3, comprising: a first biasing member that brings the first contact member into contact with the movable member; and a second biasing member that brings the second contact member into contact with the movable member.

5. The piezoelectric drive device according to claim 4, wherein the first biasing member and the second biasing member are formed by a common spring member.

6. A piezoelectric drive device as described in claim 5, comprising: a first support member including a first opposing portion that supports the first piezoelectric drive unit; and a second support member including a second opposing portion that supports the second piezoelectric drive unit, wherein the first opposing portion and the second opposing portion are arranged at opposite positions across the movable member, and the spring member is provided between the first support member and the second support member, and presses the first contact member towards the movable member via the first support member, and presses the second contact member towards the movable member via the second support member.

7. The piezoelectric drive device according to claim 6, wherein the fixed side member has a rod-shaped member extending in the translational direction, the spring member is constituted by a leaf spring, a first portion of the leaf spring is fixed to the first support member, and a second portion of the leaf spring is fixed to the second support member, and the leaf spring is configured to apply a force so that a portion of the first support member where the first piezoelectric drive unit is arranged and a portion of the second support member where the second piezoelectric drive unit is arranged approach each other.

8. The piezoelectric drive device according to claim 6, wherein the fixed side member has a rod-shaped member extending in the translational direction, the spring member is constituted by a tension coil spring, the first support member and the second support member have a portion where they intersect when viewed along the translational direction, the rod-shaped member is inserted into the first support member and the second support member at the intersecting portion, and the tension coil spring is arranged between a portion of the first support member located on the opposite side of the intersecting portion from a portion where the first piezoelectric drive unit is arranged, and a portion of the second support member located on the opposite side of the intersecting portion from a portion where the second piezoelectric drive unit is arranged.

9. The piezoelectric drive device according to claim 4, comprising: a first holding member that holds the first piezoelectric drive unit and is separate from the first biasing member; and a second holding member that holds the second piezoelectric drive unit and is separate from the second biasing member.

10. A piezoelectric drive device according to any one of claims 1 to 3, wherein when viewed along the translation direction, the first position and the second position are different positions in the circumferential direction of the movable member.

11. The piezoelectric drive device according to claim 10, wherein the first piezoelectric drive unit and the second piezoelectric drive unit are arranged in opposing positions with the movable member interposed therebetween.

12. The piezoelectric drive device according to claim 11, wherein the first axis when viewed along the first longitudinal vibration direction and the second axis when viewed along the second longitudinal vibration direction are inclined to the same side with respect to the translation direction.

13. The piezoelectric drive device according to claim 12, wherein the first axis when viewed along the first longitudinal vibration direction and the second axis when viewed along the second longitudinal vibration direction are inclined at the same angle with respect to the translation direction.

14. The piezoelectric drive device described in claim 10, wherein the first piezoelectric drive unit and the second piezoelectric drive unit are arranged such that the one surface of the first piezoelectric element and the one surface of the second piezoelectric element are inclined when viewed along the translation direction.

15. A piezoelectric drive device as described in any one of claims 1 to 3, wherein the first piezoelectric drive unit and the second piezoelectric drive unit are arranged side by side in the translational direction, and when viewed along the first longitudinal vibration direction, the first axis and the second axis are inclined in opposite directions relative to the translational direction.

16. A piezoelectric drive device according to any one of claims 1 to 3, wherein the movable member is made of metal.

17. A piezoelectric drive device according to any one of claims 1 to 3, wherein the movable member has a cylindrical shape, and the fixed member includes a shaft member that is inserted into the movable member.

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