JP4838463B2 - Vibration type actuator and vibration type drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration type actuator and a vibration type driving device.
[0002]
[Prior art]
Various types of multi-degree-of-freedom vibration type actuators (ultrasonic motors) have been proposed and will be described below.
(First conventional example)
For example, the Journal of the Robotics Society of Japan (Vol.16, No.8, pp87-94) has proposed a multi-degree-of-freedom ultrasonic motor based on the degeneration of longitudinal vibration and lateral vibration.
[0003]
This multi-degree-of-freedom ultrasonic motor excites a plurality of natural vibrations having the same natural frequency in a single vibration body to generate elliptical vibrations around three axes on the surface of the vibration body, for example, a rotating body (moving body). Is rotated around three axes.
[0004]
As a basic configuration of a vibration type actuator that obtains a driving force of multiple degrees of freedom, for example, 3 degrees of freedom with such a single vibrating body, for example, a concave portion is formed at one end of a rod-shaped vibrating body. A part of a spherical rotating body is fitted, and the rotating body is press-contacted to the vibrating body by a pressurizing mechanism. On the other hand, the vibrating body has different three-axis directions. Assuming that the axial direction is the Z-axis and the two axes orthogonal to the Z-axis are the X-axis and the Y-axis, the rotation around the Z-axis, the rotation around the X-axis, and the rotation around the Y-axis are the spherical shape. In order to be able to be applied to each of the rotating bodies, drive vibrations are generated by combining the vibration displacements in the vibrating bodies.
[0005]
The vibrating body is, for example, a piezoelectric element as an electro-mechanical energy conversion element, and the vibration body has three different vibration displacements, for example, vibration in the Z direction (longitudinal vibration), bending vibration in the ZX plane, ZY A bending vibration in a plane is given, and the two bending vibrations are formed with a temporal phase difference, so that the spherical rotating body is formed by a driving vibration formed by a combined vibration of the two bending vibrations. Rotate around the Z axis.
[0006]
In addition, the spherical rotating body is rotated around the Y axis by the combined vibration of the bending vibration and the longitudinal vibration and the ZX plane.
[0007]
Further, the spherical rotating body is rotated about the X axis by the combined vibration of the bending vibration and the longitudinal vibration and the ZY plane.
[0008]
Although the above has described the driven member that performs the rotation operation with three degrees of freedom, the rotation about the Z axis and the X, Y translation operation can be similarly described.
[0009]
(Second conventional example)
On the other hand, as shown in FIG. 10, in the Journal of Precision Engineering Vol. 61.No. A vibratory actuator that provides drive is presented.
The vibrating bodies 301a, 301b, 301c, and 301d have an annular shape, and a first pair of vibrating bodies by the vibrating bodies 301a and 301b are disposed so as to sandwich the spherical moving body 302 so as to be opposed to each other. The second pair of vibrating bodies is arranged by the vibrating bodies 301c and 301d, and these paired vibrating bodies cause the moving body to independently rotate and bring about rotational movement about two axes.
[0010]
[Problems to be solved by the invention]
However, the conventional multi-degree-of-freedom vibration type actuator has the following problems.
a: Mechanical holding mechanism for one driven member to have three degrees of freedom.
[0011]
For example, a mechanism for holding the spherical moving body is required so as to maintain the degree of freedom around three axes, and this generally has a complicated configuration or causes output loss due to the holding mechanism.
b: Limit of output by one vibrator.
[0012]
In particular, in the case of the second conventional example, when a moving motion is given to the moving body by one pair of vibrating bodies, a forced dynamic friction motion is generated between the other pair of vibrating bodies and the moving body, resulting in loss. Will increase.
[0013]
An object of the invention according to the present application is to generate an output loss by a holding mechanism for a moving body that is a driven member, and to generate a motion in one moving body with a plurality of vibrators that is efficient and efficient. It is an object of the present invention to provide a high output vibration type actuator and vibration type drive device.
[0014]
[Means for Solving the Problems]
The first configuration of the vibration type actuator that realizes the object of the present invention is as follows:
A cylindrical moving body in which a substantially cylindrical contact portion is formed ;
While moving the said cylindrical moving body in contact pressure by the pressure force of the pressure member in the cylindrical movable body, to hold the said cylindrical movable body, a drive unit which near the tip is formed in a concave shape anda two vibrating body according to the first and second vibrator having,
The two vibrators have vibration generating means for generating vibration displacements in at least three different directions in each of the drive units,
And the two vibrating body, opposing the cylindrical moving member by pressure of the pressing member applied to the cylindrical movable body through each of the driving section near the tip is formed in a concave shape While holding from two directions ,
The combination of at least two different directions or more vibration displacement are formed on the two vibrating body, the cylindrical movable body in the rotational direction perpendicular to the direction of the rotation direction and the cylindrical movable body of the cylindrical movable body It is characterized by exercise.
[0015]
A second configuration of the vibration type actuator that achieves the object of the invention according to the present application is the second configuration, wherein the vibrating body is disposed at a position facing the moving body. .
[0020]
Configuration of the vibration type driving apparatus for realizing the object of the invention according to this application has the vibration type actuator of any structure as a driving source, which was to be driven Rikomu driver by the drive source is there.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Below, the reference example and embodiment in this invention are demonstrated.
(First Reference Example ) FIGS. 1 to 5 show a reference example of the present invention.
[0022]
FIG. 1 is a perspective view of a main part showing the present reference example .
[0023]
1a and 1b are vibrating bodies formed in a cylindrical shape, and are laminated piezoelectric elements (hereinafter referred to as vibration generating means) which are electro-mechanical energy conversion elements having a laminated structure in which an electrode film is formed between a plurality of piezoelectric ceramics. 2), and a support member 204 for supporting the vibrating body is sandwiched between a first elastic body 201 and a second elastic body 202 formed of metal from both sides, as shown in FIG. The bolt 203 is screwed to form an integrated structure.
[0024]
In this reference example , a stacked piezoelectric element is used as the electro-mechanical energy conversion element. However, one piezoelectric element or a plurality of piezoelectric elements may be stacked.
[0025]
In the present reference example , the first elastic body 201 is formed with a circumferential groove 201a for expanding vibration displacement around the central axis (Z axis), and further on the drive unit 201b on the tip side of the circumferential groove 201a. For example, as shown in FIG. 2, a tapered drive portion 201 c for performing friction drive is formed concentrically with the shaft (Z-axis).
[0026]
In this reference example , as shown in FIG. 1, two vibrators 1 a and 1 b having the same configuration are used on the same axis, and each vibrator 1 a and 1 b is supported by a pedestal 101. The spring member 102 is sandwiched between the support member 102 and the pedestal 101 of the vibrating body 1 and fixed by a fixing member 103 such as a bolt member.
[0027]
Here, the plate-like support member 204 is not directly fixed to the member constituting the pedestal 101 and the fixing member 103, and the vibrating body 1 pressurizes in the Z direction in FIG. 2 through the spring member 102. is recieving. As shown in FIG. 1, the structure of the pedestal 101 is such that support pillars are fixed to the four corners of a base on a rectangular plane, and the support members of the vibrating bodies are floated and supported by opposing support pillars provided on the short side. It is not limited to.
[0028]
The moving body 401 is formed in a substantially spherical shape, and an output transmission member 410 to the outside is integrated.
[0029]
The vibrating bodies 1a and 1b are arranged such that the respective friction driving portions 201c are in contact with the outer peripheral surface of the moving body 401 and the respective central axes (Z axes) are overlapped on the same axis.
[0030]
As already described, each vibrating body receives the pressure force of the spring member 102, and by this action, the moving body 401 is pressed and contacted from both sides by the vibrating bodies 101a and 101b, and the friction drive unit 201c of the vibrating body 1 The moving body 401 is held together with the tapered shape.
[0031]
FIG. 3 shows the structure and driving principle of the vibration type actuator of this reference example .
[0032]
The columnar vibrating body 1 performs elastic vibration by the piezoelectric element 3 sandwiched and fixed between the first elastic body 201 and the second elastic body 202 near the center. FIGS. 3B, 3C, and 3D show the axial (Z) distribution of displacement in the Z, X, and Y directions, respectively.
[0033]
That is, the vibration displacement Wz in the Z direction is longitudinal vibration (vibration extending and contracting in the axial direction) having one node at the center. Further, the vibration displacement Wx in the X direction is a bending vibration having three nodes. Similarly to Wx, the vibration displacement Wy in the Y direction is a bending vibration having three nodes.
[0034]
Here, when the vibration displacement Wz and the vibration displacement Wx are generated so that the temporal phase difference is 90 degrees, an ellipse around the Y axis (in the XZ plane) near the end of the vibration body 1, for example, the 201c portion. Or a circular motion is formed.
[0035]
If the temporal phase difference of the vibration displacement is reversed (-90 degrees), the first rotating body 401 rotates in the opposite direction.
[0036]
When the vibration combination is changed and the vibration displacement Wz and the vibration displacement Wy are generated so that the temporal phase difference is 90 degrees, an ellipse around the X axis (in the YZ plane) or near the 201c portion of the vibration body 1 A circular motion is formed.
[0037]
Similarly, when the vibration combination is changed and the vibration displacement Wx and the vibration displacement Wy are generated so that the temporal phase difference is 90 degrees, the vibration body 1 has a portion around the Z axis (in the XY plane) around the 201c portion. An elliptical or circular motion is formed.
[0038]
The driving method of the vibrating body in the present reference example using the vibrating body having such an action will be described with reference to FIG.
[0039]
The coordinate axes are shown as in FIG. 4, and the case where the moving body 401 is rotated clockwise about the Y axis is shown.
[0040]
When the vibration displacements Wz and Wx are generated so that the vibration displacement Wz of the vibration body 1a is delayed by 90 degrees with respect to the vibration displacement Wx, the behavior of the vicinity of the end of the vibration body 1, for example, the portion 201c is as shown in FIG. It becomes an elliptical motion. A force that moves in the −X direction is applied to the −Z side of the moving body 401 that contacts the 201c portion.
[0041]
Similarly, when vibration displacements Wz and Wx are generated so that the vibration displacement Wz is delayed by 90 degrees with respect to the vibration displacement Wx with respect to the vibration displacement Wb, the behavior of the vicinity of the end portion of the vibration body 1, for example, the portion 201c. Becomes elliptical motion as shown in FIG. A force that moves in the X direction is applied to the Z side of the moving body 401 that contacts the 201c portion. Due to the resultant force of the two vibrating bodies 1a and 1b applied to the moving body 401, the moving body 401 rotates clockwise about the Y axis.
[0042]
When the temporal phase difference between the vibration displacement Wz and the vibration displacement Wx generated in each vibration body is reversed, the moving body 401 performs a counterclockwise rotational movement about the Y axis.
[0043]
Similarly, by generating the vibration displacements Wz and Wy in each vibrating body 1, the moving body 401 can obtain a rotational motion around the X axis, and by generating the vibration displacements Wx and Wy, the moving body 401 can be rotated around the Z axis. Rotational motion is obtained.
[0044]
Vibrator 1 a and the vibrating body 1b has the same performance because the same configuration. Since the two vibration bodies have the same generated force, the respective vibration displacements Wx are made equal, and at the same time, driving is performed to make the vibration displacements Wz equal. The body 401 performs a rotational motion with the central axis of the moving body itself as the center of rotation. Therefore, a mechanism for holding the moving body 401 is not necessary.
[0045]
Although the above has described the rotational motion about the X, Y, and Z axes, the direction of the rotational motion is not limited thereto. By appropriately combining the vibration displacements Wx, Wy, and Wz, a rotational motion in an arbitrary direction is realized.
[0046]
The number of the vibrating bodies 1 is not limited to the form shown so far. FIG. 5 is a perspective view showing another embodiment of the vibration type actuator of this reference example . The first vibrating body 1a, the second vibrating body 1b, and the third vibrating body 1c are arranged in a plane including the rotation center of the moving body 401 at approximately 120 ° intervals. Except this configuration, it is the same as that shown in the form of FIG. By providing the force generated by the three vibrating bodies 1a, 1b, and 1c to one moving body 401, a high output of the vibration type actuator can be easily realized.
[0047]
In this reference example , three vibrators are arranged at approximately 120 ° intervals. However, the number and arrangement method of the vibrators are not limited to this, and the longitudinal axes of four or more vibrators move. It is also possible to arrange the body 401 so as to substantially coincide with the center of rotation.
[0048]
(Second Reference Example ) FIG. 6 is a perspective view of the main part showing the form of the second reference example of the present invention.
[0049]
1c and 1d are vibrating bodies formed in a quadrangular prism shape and have the same shape. The vibrating bodies 1c and 1d have a structure in which piezoelectric element plates 4a to 4d as vibration generating means are bonded to a surface having a long side of an elastic body 205 made of metal by bonding or the like, and the elastic body 205 is integrated. Is formed with a support member 204 for supporting the vibrating body.
[0050]
A contact portion 402a of the moving body 402 that comes into contact with the drive unit 205a, which is one end portion of the vibrating body, is formed in a substantially planar shape, is disposed to face the vibrating bodies 1c and 1d, and is in pressure contact.
[0051]
The press contact method between the vibrating bodies 1c, 1d and the moving body 402, the holding method of the vibrating body, and the like are the same as those in the first reference example shown in FIG.
[0052]
FIG. 7 shows the operating principle of the vibrating bodies 1c and 1d.
[0053]
The piezoelectric element plate 4a in Y Z surface of the elastic member 205 constituting the vibrator, 4b are disposed, X Z plane piezoelectric element plate 4c in, 4d are arranged, the vibrating body by the reverse piezoelectric effect of the piezoelectric element plate Performs elastic vibration.
[0054]
When an AC drive signal having the same phase is applied to these piezoelectric element plates 4a, 4b, 4c and 4d, the vibrating bodies 1c and 1d generate longitudinal vibration having one node at the center, as shown in FIG. 7B. generating a vibration displacement distribution W z in the Z-direction.
[0055]
When the AC drive signals applied to the piezoelectric element plates 4c and 4d are left as they are and the AC drive signals having opposite phases are applied to the piezoelectric element plates 4a and 4b, the vibrating bodies 1c and 1d generate bending vibrations having three nodes. The vibration displacement distribution Wx in the X direction is generated as shown in FIG.
[0056]
Similarly, when an AC drive signal having an antiphase is applied to the piezoelectric element plates 4c and 4d while the AC drive signal having the antiphase described above is applied to the piezoelectric element plates 4a and 4b, three vibrating bodies 1c and 1d are provided. A bending vibration having a knot is generated, and a vibration displacement distribution Wy in the Y direction is generated as shown in FIG.
[0057]
The moving body 402 is driven by combining these three different vibrations.
[0058]
When the vibration displacement Wz and the vibration displacement Wx are generated so that the temporal phase difference is 90 degrees, an elliptical or circular motion around the Y axis (in the XZ plane) is formed in the drive unit 205a of the vibrating bodies 1c and 1d. Then, the moving body 402 is driven in the X direction.
[0059]
When the vibration combination is changed and the vibration displacement Wz and the vibration displacement Wy are generated so that the temporal phase difference becomes 90 degrees, the drive unit 205a of the vibrating bodies 1c and 1d is rotated around the X axis (in the YZ plane). The elliptical or circular motion is formed, and the moving body 402 is driven in the Y direction.
[0060]
Similarly, when the vibration combination is changed to generate the vibration displacement Wx and the vibration displacement Wy so that the temporal phase difference becomes 90 degrees, the drive unit 205a of the vibrating bodies 1c and 1d is rotated around the Z axis (XY plane). Inner) ellipse or circular motion is formed, and the movable body 402 is driven to rotate around the Z axis. Similarly to the first reference example , the moving body 402 moves around the X direction, the Y direction, and the Z axis by combining the generated forces of the vibrating bodies 1c and 1d. The direction of motion is not limited to these, and an arbitrary motion is generated by a combination of vibrations.
[0061]
(Embodiment of the present invention) FIG. 8 is a perspective view of a main part showing a shape state of implementation of the present invention. The basic configuration conforms to the first reference example shown in FIG. However, the moving body 403 has a central axis in the Y direction shown in FIG. 8 and is formed with a substantially cylindrical contact portion 403a.
[0062]
The first elastic member 1e and the second elastic body 1f, are arranged driving portion 206c which is formed in a concave shape, as both shown in FIG. 9, for example in the Y-axis direction in the vicinity of the tip.
[0063]
The drive part 206c formed on the first elastic body 1e and the second elastic body 1f is brought into pressure contact with the contact part 403a which is the outer peripheral part of the movable body 403 formed in a cylindrical shape.
[0064]
The moving body 403 moves in the Y direction and rotates around the Y axis by the same action as described in the first or second reference example .
[0067]
【The invention's effect】
As described above, according to the present invention, it is possible to drive a moving body having a plurality of degrees of freedom without having a mechanical holding mechanism.
In addition, a high output multi-degree-of-freedom vibration type actuator can be realized by driving a moving body with a plurality of vibrating bodies.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a first reference example of the present invention.
FIG. 2 is a side sectional view of the vibrating body shown in FIG.
3 is a vibration body shown in FIG. 1, wherein (a) is a perspective view, and (b), (c), and (d) are diagrams showing vibration displacement distributions.
FIG. 4 is a drive image diagram of a first reference example .
FIG. 5 is a perspective view showing a modification of the first reference example .
FIG. 6 is a perspective view showing a second reference example of the present invention.
7 is a vibration body shown in FIG. 6, in which (a) is a perspective view, and (b), (c), and (d) are diagrams showing vibration displacement distributions.
Perspective view showing the shape condition of implementation of the invention; FIG.
9 is a side cross-sectional view of the vibrating body of FIG.
FIG. 10 is a perspective view showing a conventional multi-degree-of-freedom vibration type actuator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Vibrating body 4 ... Piezoelectric element 401, 402, 403 ... Moving body

Claims (3)

A cylindrical moving body in which a substantially cylindrical contact portion is formed ;
While moving the said cylindrical moving body in contact pressure by the pressure force of the pressure member in the cylindrical movable body, to hold the said cylindrical movable body, a drive unit which near the tip is formed in a concave shape anda two vibrating body according to the first and second vibrator having,
The two vibrators have vibration generating means for generating vibration displacements in at least three different directions in each of the drive units,
And the two vibrating body, opposing the cylindrical moving member by pressure of the pressing member applied to the cylindrical movable body through each of the driving section near the tip is formed in a concave shape While holding from two directions ,
The combination of at least two different directions or more vibration displacement are formed on the two vibrating body, the cylindrical movable body in the rotational direction perpendicular to the direction of the rotation direction and the cylindrical movable body of the cylindrical movable body A vibration type actuator characterized by being moved.   The vibration type actuator according to claim 1, wherein the vibrating body is disposed at a position facing the moving body. 3. A vibration type driving apparatus having the vibration type actuator according to claim 1 or 2 as a drive source and driving a driven body by the drive source.

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