JP5669444B2 - Vibration type driving device - Google Patents

Description

  The present invention relates to a vibration type driving device called an ultrasonic motor or the like.

As a vibration type driving device that drives a driven body with a vibrator using an electro-mechanical conversion element, for example, there is one using a vibrator in which a diaphragm formed of a metal elastic member and a piezoelectric element are integrated by bonding or the like. (For example, patent document 1).
The vibrator in this vibration type driving device is formed with two support portions so as to extend to the side of the vibrator.
The support portion is provided with a fixing portion to be joined to the vibrator holding portion for holding and fixing the vibrator.

JP 2005-354787 A

By the way, the output and efficiency of the vibration-type driving device using the vibrator depends on the conversion efficiency of the vibration energy generated in the vibrator into the relative motion with the driven body.
At that time, one of the causes of the vibration energy of the vibrator being consumed is that when the vibration energy generated in the vibrator is transmitted to the driven body, a part of the vibration energy is provided on the support portion of the vibrator. May be due to concentrating on.
That is, the consumption amount or ratio of vibration energy from the fixed portion provided on the support portion of the vibrator directly affects the performance of the vibration type driving device.
Therefore, in order to improve the performance of the vibration type driving device, it is necessary to suppress the consumption of vibration energy from the fixed portion provided in the support portion of the vibrator.

  In view of the above problems, the present invention provides a vibration type driving device that can suppress consumption of vibration energy from a fixed portion provided on a support portion of a vibrator and can improve output and efficiency. With the goal.

The vibration type driving device of the present invention includes at least an electro-mechanical energy conversion element and an elastic vibration body in which the electro-mechanical energy conversion element is joined to form a contact portion, and an elliptical motion is generated in the contact portion. A configured oscillator, and
A driven body having a driven body that is in pressure contact with the contact portion of the vibrator and relatively moves by the elliptical motion,
The vibrator has a support portion extending from either one of two opposing side surfaces of the elastic vibrator,
The support part includes a fixing part for joining a vibrator holding part for holding a vibrator, a connecting part for connecting the fixing part and the elastic vibrator, and the fixing part to the elastic vibrator side. A vibration displacement suppressing portion that overhangs and suppresses vibration displacement of the fixed portion ;
Is formed.

  ADVANTAGE OF THE INVENTION According to this invention, the vibration type drive device which suppresses consumption of the vibration energy from the fixing | fixed part provided in the support part of the vibrator | oscillator, and can aim at the improvement of an output and efficiency is realizable.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. The top view explaining the structure of the vibrator | oscillator of the vibration type drive device in embodiment and Example 1 of this invention. FIG. 3 is a perspective view illustrating a vibration mode of a vibrator according to the first embodiment of the present invention. The top view explaining the structural example of the vibration type drive device by another form in Example 1 of this invention. The top view explaining the structure of the diaphragm of the vibration type drive device in Example 2 of this invention. The perspective view showing the vibration mode of the vibrator in Example 2 of the present invention. The perspective view showing the vibration mode of the vibrating body which does not provide the vibration displacement suppression part of this invention.

A configuration example of the vibration type driving device in the embodiment of the present invention will be described with reference to FIGS. 1 and 2.
The vibration type driving device of the present embodiment includes at least an electro-mechanical energy conversion element 13 and a substantially rectangular elastic vibration body 11 in which the electro-mechanical energy conversion element is joined and a contact portion 12 is formed. The contact portion 12 includes a vibrator 1 configured to generate an elliptical motion.
In addition, a driven body 3 that is in pressure contact with the contact portion 12 of the vibrator 1 and relatively moves by the elliptical motion is provided.
The vibrator 1 has a support portion that extends symmetrically from either side of both sides of the substantially rectangular elastic vibrator 11.
The support portion includes a fixing portion 11-B for joining to the vibrator holding portion 2 for holding and fixing the vibrator 1, and a connecting portion for joining the fixing portion 11-B and the elastic vibrator 11 to each other. 11-C and 11-D are formed.
Furthermore, a vibration displacement suppressing portion (also referred to as a protruding portion in the present invention) 11-E that suppresses the vibration displacement of the fixing portion protruding from the fixing portion 11-B toward the elastic vibrating body 11 is formed.
As such an overhanging portion 11-E, a large vibration displacement is generated as compared with the fixed portion, and by forming an overhanging portion that functions as a vibration displacement suppressing portion, vibration energy is stored in the overhanging portion 11-E, Concentration of vibration energy on the fixing part 11-B can be avoided.
By setting it as such a structure, it becomes possible to suppress the vibration displacement of a fixing | fixed part and to prevent the dissipation of energy from a fixing | fixed part.
At this time, it is desirable that the connecting portion be given a certain angle with respect to the normal direction of the symmetry plane. Thereby, the length of the connection part which connects a vibration part and a fixing | fixed part can be earned, and propagation of the vibration energy to a fixing | fixed part can further be reduced.
Moreover, it is desirable that at least a part of the connecting portion is formed thinner than the fixing portion 11-B and the overhang portion 11-E. Thereby, the rigidity of a connection part can be lowered | hung and it becomes possible to further reduce propagation of the vibration energy to a fixing | fixed part.
Further, in order to generate the elliptical motion, the elastic vibration body 11 is excited with two different shapes of out-of-plane bending vibration modes, and a contact portion provided on the surface of the elastic vibration body 11 by the combined vibration of these vibration modes. It is desirable to make a relative movement with the driven body. Thereby, it is possible to form a support portion that is particularly adapted to the vibration form, and to realize a thin and small vibrator that is excellent in vibration energy efficiency.
In the present invention, the shape, size, and mass of the vibration displacement suppressing portion (overhang portion) are not particularly limited as long as there are no other vibration characteristics, processing, and cost problems. For example, a plate shape (square shape, circular shape), a rod shape, or a block shape can be employed. Further, in order to adjust the mass or the like, a hole or a groove can be provided in the vibration displacement suppression portion (overhang portion) as necessary.

In the present invention, the vibration displacement suppressing portion (projecting portion) can be easily designed by the following procedure.
(1) Measure the vibration displacement amount of the contact portion (the effect of the vibration displacement suppression portion can be easily confirmed by using it as a representative value of the vibration displacement of the vibrator. The amount of displacement can also be adopted).
(2) The average vibration displacement amount of the support portion is measured.
(3) = Adjust the size, shape, and mass of the vibration displacement suppression portion (projecting portion) so that (2) / (1) becomes smaller.
As a method of measuring the amount of vibration displacement, it is desirable to be able to measure without contacting the vibrator, and a laser vibrometer or the like may be used.
In the step (3), the value of (2) / (1) is ideally designed to be 0. However, according to the knowledge of the present inventors, the value was obtained as described above ( In the case of Mode A, the value of 3) is preferably 0.2 or less, more preferably 0.1 or less. Similarly, in the case of Mode B, it is preferably 1.0 or less, more preferably 0.5 or less. Moreover, the adjustment method of the size, shape, and mass of the vibration displacement suppression portion (overhang portion) is adjusted by performing a process of increasing the mass body by cutting, cutting, drilling, bonding, welding, or the like of the overhang portion. be able to.

Examples of the present invention will be described below.
[Example 1]
As a first embodiment, a configuration example of an ultrasonic motor to which the configuration of the vibration type driving device of the present invention is applied will be described with reference to FIG.
As shown in FIG. 1, the ultrasonic motor 4 of the present embodiment is mainly held in a pressure contact state with the vibrator 1, the vibrator holding portion 2 for holding and fixing the vibrator 1, and the vibrator 1. And a driven body 3.
The ultrasonic motor 4 includes a flexible substrate that electrically connects the vibrator 1 and the outside, a guide member for the driven body 3, and the like, and these constituent elements are well known, and thus detailed description thereof is omitted. To do.

The driven body 3 includes a rectangular bar-shaped driven body base 31 made of a magnet material, a material bonded to the driven body base 31 and having a high friction coefficient and friction durability, and in this embodiment, the surface is nitrided. And a plate-like friction member 32 made of martensitic SUS440C.
The vibrator 1 is processed from, for example, a plate material of SUS420J2, which is a ferromagnetic martensitic stainless steel having a thickness of 0.3 mm.
The rectangular plate-like elastic vibration body 11 in which the friction member 32 of the driven body 3 is in pressure contact with two contact portions 12 (FIG. 2) to be described later on one surface thereof is similarly a rectangular plate. It consists of a piezoelectric element plate 13 (electro-mechanical energy conversion element) having a thickness of, for example, 0.5 mm joined to the other surface of the elastic vibration member 11 by adhesion or the like, and forms a so-called unimorph structure.
The magnet material constituting the driven body base 31 forms a magnetic circuit in cooperation with the ferromagnetic SUS420J2 constituting the elastic vibrator 11.
Further, the friction member 32 generates a friction force with the contact portion 12 when the driven body 3 is pressed against the vibrator 1.

FIG. 2 is a plan view of the vibrator 1 shown in FIG.
In the vibrator 1 of FIG. 2, the elastic vibrating body 11 includes a substantially rectangular vibrating portion 11 -A. In addition, a fixed portion 11-B (shaded portion in the figure) that joins the vibrator holding portion 2 to hold and fix the vibrator 1, and a connection that couples the vibrating portion 11-A and the fixed portion 11-B. The parts 11-C and 11-D and the overhanging part 11-E which is a vibration displacement suppressing part are formed.
The vibrator 1 is formed symmetrically with respect to the XZ plane in the figure.

To operate the ultrasonic motor 4, an AC electric field is applied to the piezoelectric element plate 13 to excite the transducer 1 in two out-of-plane bending modes.
FIG. 3 shows the shape of the vibration mode used at this time.
MODE-A is an out-of-plane bending primary mode in which two nodes appear in the elastic vibrator 11 in parallel to the X direction in the figure.
MODE-B is an out-of-plane bending secondary mode in which three nodes appear on the elastic vibrating body 11 substantially parallel to the Y direction in the figure.
By superimposing these two modes, an elliptical motion is generated on the surface of the contact portion 12, and a relative motion is generated between the driven body 3 that is in pressure contact with the contact portion 12 and the vibrator 1.
Similarly, FIG. 7 shows the shape of the vibration mode of the vibrator that does not have the overhanging portion that is the vibration displacement suppressing portion of the present invention.

The displacement amount of the two vibration modes of the vibrator 1 and the energy consumption during vibration directly affect the output and efficiency of the ultrasonic motor 4 with respect to the output and efficiency of the ultrasonic motor 4.
Therefore, the method for fixing the vibrator 1 is an important requirement for the performance of the ultrasonic motor 4.
Specifically, the vibration displacement of the fixed portion 11-B is required to be small in the two vibration modes shown in FIG.
In the present embodiment, the connecting portion 11-D is formed near the node position in the vibration mode shape of MODE-A to prevent an increase in vibration displacement of the fixed portion 11-B.
However, the node position in MODE-B is different from that in MODE-A, and as a result, the vibration displacement of the connecting portion 11-D is large.

In the present embodiment, the configuration around the support portion is configured as follows (1) to (4) so that the displacement of the connecting portion 11-D is suppressed by the fixing portion 11-B.
(1) In order to reduce the bending rigidity of the connecting portion 11 -D, the plate thickness is formed thinner than other portions of the elastic vibrating body 11. Further, the length is secured by extending with an angle with respect to the XZ plane.
(2) The consolidated portion 11-C to reduce the width in the X direction from the fixing unit 11-B, to ensure a length that extends in the Y direction, configured to reduce the bending stiffness.
(3) consolidation unit 11-C is extended in the Y-direction than the binding portions of the connecting portions 11- D, by generating a displacement in this part, vibration of the fixed part 11-B and let stored vibrational energy Configure to avoid energy concentration.
(4) A protruding portion 11-E is formed from the fixed portion 11-B toward the vibrating portion 11-A, and vibration energy is stored in the protruding portion 11-E so that the vibration energy of the fixed portion 11-B is concentrated. Configure to avoid.
With the above configuration, it is possible to realize an ultrasonic motor that suppresses the amount of displacement of the support portion as in MODE-B shown in FIG.

In this example, the relationship between the presence / absence of the displacement suppression portion (projecting portion) and the displacement amount of the support portion was examined by measuring the displacement amount of the following representative points of the vibrator. The results are shown in Table 1.
The value in the table indicates the following value (3), and the smaller the value, the greater the displacement suppression effect.
(1) Vibration displacement at the representative point of the vibrator In the portion 11-A in FIG.
As is clear from Table 1, the displacement amount (average vibration displacement amount) of the support portion can be reduced by providing the displacement suppression portion (projecting portion) of the present invention.
[Table 1]

A configuration example of a vibration type driving device having a different form from the configuration of the first embodiment will be described with reference to FIG.
In the present embodiment, the driven body 3 has an annular shape and is configured to perform a rotational motion around its central axis.
Two pairs of the vibrator 1 and the vibrator holding portion 2 are used, and are arranged at positions facing the central axis of the driven body.
Each vibrator 1 is fixed to an annular fixing member 5 via a vibrator holding portion 2.
The parts 11-B to 11-E of the elastic vibration member 11 have the same configuration and function as the elastic vibration member 11 shown in FIG. 2, but in this embodiment, the inner and outer diameters of the fixing member are shown in FIG. The shape is determined so as to fit in the projection.

[Example 2]
FIG. 5 is a plan view of the vibrator 1 used in the vibration type driving apparatus according to the second embodiment of the present invention.
Only the portions different from the elastic vibrator 11 described in FIG. 2 will be described below.
The vibrator 1 formed by the elastic vibrator 11 and the driven body 3 (not shown) perform relative motion in the X direction in the figure. 11-B to 11-E extend in the Y direction in the figure orthogonal to the relative motion direction.
The elastic vibrating body 11 has a symmetrical shape with respect to the YZ plane. The connecting portion 11-D extends from the vibrating portion 11-A substantially parallel to the YZ plane.
When the elasticity of the connecting portion 11-D is sufficiently obtained, the connecting portion 11-D does not need to have an angle with respect to the YZ plane as shown in the present embodiment.

FIG. 6 shows a vibration mode at the time of driving in the vibrator using the elastic vibrator 11.
The deformation mode of the vibration unit 11-A is the same as the vibration mode in the first embodiment illustrated in FIG.
In the present embodiment, the connecting portion 11-D is formed near the node position in the vibration mode shape of MODE-B to prevent the vibration displacement of the fixed portion 11-B from increasing.
However, since the node position in MODE-A is different from that in MODE-B, the vibration displacement of the connecting portion 11-D is in a large state.
Also in the present embodiment, as in the first embodiment, it is possible to suppress the displacement amount of the fixing portion 11-B.

1: vibrator 2: vibrator holder 3: driven body 4: ultrasonic motor 11: elastic vibrator 13: piezoelectric element plate (electro-mechanical energy conversion element)

Claims (6)

A vibrator having at least an electro-mechanical energy conversion element and an elastic vibration body in which the electro-mechanical energy conversion element is joined to form a contact portion, and configured to generate an elliptical motion in the contact portion;
A driven body having a driven body that is in pressure contact with the contact portion of the vibrator and relatively moves by the elliptical motion,
The transducer is in the elastic vibration member has a support portion extending from the two sides side which pair of pairs direction,
The support part includes a fixing part for joining a vibrator holding part for holding a vibrator, a connecting part for connecting the fixing part and the elastic vibrator, and the fixing part to the elastic vibrator side. A vibration displacement suppressing portion that overhangs and suppresses vibration displacement of the fixed portion ;
A vibration type driving apparatus characterized in that is formed. The vibration displacement suppression portion, the vibration type driving apparatus according to claim 1, wherein the benzalkonium generate large vibration displacement relative to the fixed part.   The vibration type driving device according to claim 1, wherein the connecting portion is formed with an angle with respect to a direction in which the support portion extends.   4. The vibration type driving device according to claim 1, wherein at least a part of the connecting portion is formed thinner than the fixed portion and the overhang portion. 5.   The elliptical motion is an elliptical motion formed by a combined vibration of these vibration modes by exciting the elastic vibration body in two different out-of-plane bending vibration modes. The vibration type driving device according to claim 1.   The vibration type driving device according to claim 1, wherein the elastic vibration body has a substantially rectangular shape.

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