JP2006271143A - Vibration wave motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration wave motor whose cost can be reduced and calm property can be realized. <P>SOLUTION: The motor includes a vibration body 1 having a piezoelectric body 2 excited by a driving signal and a circular elastic body 3 which is bonded to the piezoelectric body 2 and generates a progressive vibration wave on a driving face by excitation, a mobile 5 which is pressurized to and is brought into contact with the driving face of the elastic body 3 and is driven by the progressive vibration wave, a flange part 3c supporting the elastic body 3 on an inner peripheral face and a pressurizing member 9 pressurizing the elastic body 3 to the mobile 5 through the flange part 3c. A butyl rubber sheet 31 suppressing occurrence of abnormal noise due to friction driving of the vibration body 1 and the mobile 5 is arranged between the vibration body 1 and the piezoelectric body 2 across the flexible printed board 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vibration wave motor having an improved vibrating body.

  Conventionally, this type of vibration wave motor, as disclosed in Patent Document 1, for example, generates a progressive vibration wave on the driving surface of an elastic body by using expansion and contraction of a piezoelectric body, and by this traveling wave, An elliptical motion is generated on the drive surface, and the movable element in pressure contact with the wavefront of the elliptical motion is driven. Since such a vibration wave motor has a feature that it has a high torque even at a low rotation, when mounted on a drive device, the gear of the drive device can be omitted, so that silence can be achieved by eliminating gear noise. There is an advantage that it can be achieved and positioning accuracy can be improved.

In recent years, for such vibration wave motors, the combination of the vibrator driving surface and the slider sliding surface has conventionally been a combination of metal and resin for reasons such as cost reduction and simplification of component accuracy management. However, it is shifting to a combination of metals (including metal-based surface treatment).
For example, when a resin sliding member is affixed to the mover, processing of two parts of the mover base material and the sliding member and man-hours for pasting occur, and the mover itself is made of resin However, dimensional accuracy cannot be obtained only by molding, and a processing man-hour for obtaining dimensional accuracy is required, which is the reason for increasing the cost.

  On the other hand, when the sliding surface of the slider is made of metal or metal surface treatment, the processing and assembly man-hours are greatly reduced, and the geometric tolerances such as the dimensional tolerance and flatness of the sliding surface are managed. Therefore, a significant cost reduction can be expected.

The first characteristic of this vibration wave motor is quietness. However, as a principle of the vibration wave motor, the vibrating body driving surface and the slider sliding surface come into contact with each other and are frictionally driven. Therefore, various devices are required to suppress the abnormal noise generated at this time.
If the elastic body drive surface is made of a metal such as stainless steel and the slider sliding surface is made of resin as in the past, a material that attenuates vibration and sound can be selected for the resin itself, or a soft resin It is possible to suppress the generation of abnormal noise during operation of the vibration wave motor by selecting the button and improving the adhesion to the vibrating body drive surface.

However, if the vibrating body drive surface and the slider sliding surface are made of metal (including metal surface treatment), the metal itself cannot be expected to have a damping effect on vibration and sound, and the surface is soft. In addition, since it cannot be expected as much as resin, as a result, it becomes difficult to prevent unpleasant noise during friction driving, which has been a major problem of cost reduction.
Japanese Patent Publication No. 1-17354

  An object of the present invention is to provide a vibration wave motor that can achieve both cost reduction and quietness.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to the Example of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention of claim 1 comprises a piezoelectric body (2) excited by a drive signal and an annular or cylindrical elastic body (3) joined to the piezoelectric body and generating a progressive vibration wave on the drive surface by the excitation. A movable body (1) that is pressed against the driving surface of the elastic body and driven by the progressive vibration wave; and the elastic body is connected to the inner peripheral surface and / or the outer peripheral surface. A vibration wave motor comprising: a support part (3c) supported by: a moving part; and a pressing part (9) that pressurizes the elastic body through the support part. The vibration wave motor is characterized by including an abnormal noise suppressing member (31, 32) that suppresses the generation of abnormal noise due to friction drive between the vibrating body and the moving element.
According to a second aspect of the present invention, in the vibration wave motor according to the first aspect, the driving surface of the elastic body and the sliding surface of the moving member have a Vickers hardness Hv of 250 or more. It is a motor.
According to a third aspect of the present invention, in the vibration wave motor according to the first or second aspect, the vibration wave motor includes a flexible printed circuit board (4) connected to the piezoelectric body and applying a driving signal, and the noise suppressing member (31). Is a vibration wave motor characterized by being mounted on the flexible printed circuit board (4).
According to a fourth aspect of the present invention, in the vibration wave motor according to the third aspect, the noise suppressing member (31) is disposed on the piezoelectric body (2) side of the vibrating body (1). It is a vibration wave motor characterized by being arrange | positioned in the state which does not contact directly.
According to a fifth aspect of the present invention, in the vibration wave motor according to any one of the first to fourth aspects, the noise suppressing member (32) is a vibration-proof rubber having a Shore hardness Hs of 30 to 70. It is a vibration wave motor characterized by being.
The invention according to claim 6 is the vibration wave motor according to claim 1 or 2, wherein the noise suppressing member (32) is mounted on an outer peripheral surface and / or an inner peripheral surface of the vibrating body (1). This is a vibration wave motor characterized by the above.
The invention according to claim 6 is the vibration wave motor according to any one of claims 1, 2, or 6, wherein the noise suppressing member (32) is a silicone-based or polypropylene-based vibration-proof resin. The vibration wave motor is characterized by being formed from.

As described above, the present invention has the following effects.
(1) Since the noise suppressing member is attached to the vibrating body, it is possible to absorb an unpleasant sound generated during friction driving.
(2) Since the noise suppressing member is attached to the piezoelectric body via the flexible printed circuit board, the effect of vibration attenuation is maintained moderately, and the noise is suppressed and the motor performance is not deteriorated.
(3) Since the noise suppressing member is mounted on the outer peripheral surface and / or the inner peripheral surface of the vibrating body, vibration having an amplitude in the radial direction can be suppressed.

  The present invention aims to provide a vibration wave motor that can achieve both cost reduction and quietness, by attaching a butyl rubber sheet 31 to the piezoelectric body surface of the vibrating body 1 via the flexible printed circuit board 4, and then proceeding. This is achieved by suppressing vibrations other than vibration waves.

Embodiments of a vibration wave motor according to the present invention will be described below in detail with reference to the accompanying drawings. In the following embodiments, an ultrasonic motor using an ultrasonic vibration region will be described as an example of a vibration wave motor.
FIG. 1 is a diagram illustrating an ultrasonic motor according to a first embodiment of the present invention.
The ultrasonic motor 100 according to the first embodiment includes a vibrating body 1 having a piezoelectric body 2 and an elastic body 3 and a moving element 5 that is in pressure contact with the driving surface of the elastic body 1. The vibrating body 1 side is fixed and the movable element (relative motion member) 5 is driven.

  As will be described later, the vibrating body 1 includes an electro-mechanical conversion element (hereinafter referred to as a piezoelectric body) 2, such as a piezoelectric element or an electrostrictive element that converts electrical energy into mechanical energy, and a piezoelectric body 2. It is comprised from the elastic body 3 which joined. The traveling body 1 generates traveling waves. In the first embodiment, the traveling body 1 will be described as traveling waves of four waves as an example.

The elastic body 3 is made of a metal material having a large resonance sharpness. The shape of the elastic body 3 is an annular shape. A groove is cut on the opposite surface to which the piezoelectric body 2 is joined. 3) The tip surface of 3b becomes the driving surface and is brought into pressure contact with the moving element 5. The reason for cutting the groove is to make the neutral surface of the traveling wave as close as possible to the piezoelectric body 2 side, thereby amplifying the amplitude of the traveling wave on the drive surface. In this embodiment, the portion where the groove is not cut is referred to as a base portion 3a. In the base portion 3a, the piezoelectric body 2 is bonded to the surface opposite to the groove side. The elastic body 3 has a NiP surface treatment on its drive surface.
The elastic body 3 is provided with a flange portion 3c on the inner peripheral side of the base portion 3a, and is fixed to the fixing member 6 (6a, 6b) using that portion. The flange part 3c has a form located at the center of the thickness of the base part 3a.

  The piezoelectric body 2 is divided into portions corresponding to two phases (A phase and B phase) along the circumferential direction, and in the portions corresponding to each phase, the polarization alternates every ½ wavelength. The arranged elements are arranged, and an interval of ¼ wavelength is provided between the portion corresponding to the A phase and the portion corresponding to the B phase. In the piezoelectric body 2, wiring of an FPC (flexible printed circuit board) 4 is connected to each phase electrode, and a driving voltage is applied.

The mover 5 is made of a light metal such as aluminum, and the surface of the sliding surface is anodized to improve wear resistance.
The output shaft 8 is coupled to the mover 5 via the rubber member 7 and is rotated integrally with the mover 5. The rubber member 7 between the output shaft 8 and the mover 5 has a function of coupling the mover 5 and the output shaft 8 with adhesiveness due to rubber, and vibration for not transmitting vibration from the mover 5 to the output shaft 8. Absorption function is required, and butyl rubber or the like is preferable.

  The pressure member 9 is a coil spring or the like, and is provided between the gear member 10 fixed to the output shaft 8 and the bearing receiving member 11. The gear member 10 is inserted so as to fit in the D cut of the output shaft 8 and is fixed by a stopper 12 such as an E clip so as to be integrated with the output shaft 8 in the rotation direction and the axial direction. Further, the bearing receiving member 11 is inserted on the inner diameter side of the bearing 13, and the bearing 13 is inserted on the inner diameter side of the fixed member 6a. By adopting such a structure, the moving element 5 comes into pressure contact with the drive surface of the vibrating body 1.

FIG. 2 is a block diagram illustrating the ultrasonic motor driving apparatus 20 according to the first embodiment.
First, driving and control of the ultrasonic motor will be described.
The oscillating unit 21 is a part that generates a drive signal having a desired frequency according to a command from the control unit 22. The phase shifter 23 is a part that divides the drive signal generated by the oscillator 21 into two drive signals having a 90 ° phase difference. The amplifying units 24 and 25 are portions for boosting the two drive signals divided by the phase shift unit 23 to desired voltages, respectively. Drive signals from the amplifying units 24 and 25 are transmitted to the ultrasonic motor 100, and traveling waves are generated in the vibrating body 1 by application of the drive signals, and the movable element 5 is driven.
The detection unit 26 is configured by an optical encoder, a magnetic encoder, or the like, and is a part that detects the position and speed of a driven object driven by driving the moving element 5. The control unit 22 is a part that controls driving of the ultrasonic motor 100 based on a drive command from the CPU. The control unit 22 is a part that receives the detection signal from the detection unit 26, obtains position information and speed information based on the value, and controls the frequency of the oscillation unit 21 so as to be positioned at the target position. .

According to the configuration of the first embodiment, the ultrasonic motor control device 20 operates as follows.
First, the target position is transmitted to the control unit 22. A drive signal is generated from the oscillating unit 21, and the signal is divided into two drive signals having a phase difference of 90 ° by the phase unit 23, and is amplified to a desired voltage by the amplification units 24 and 25.
The drive signal is applied to the piezoelectric body 2 of the ultrasonic motor 100, and the piezoelectric body 2 is excited, and the fourth-order bending vibration is generated in the elastic body 3 by the excitation. The piezoelectric body 2 is divided into an A phase and a B phase, and drive signals are applied to the A phase and the B phase, respectively. The positional phase of the fourth-order bending vibration generated from the A phase and the fourth-order bending vibration generated from the B phase are shifted by ¼ wavelength, and the A-phase driving signal and the B-phase driving are shifted. Since the signal is 90 ° out of phase, the two bending vibrations are combined into four traveling waves. An elliptical motion is generated at the front of the traveling wave. Therefore, the movable element 5 that is in pressure contact with the drive surface is frictionally driven by this elliptical motion.
A detection unit 26 such as an optical encoder is arranged in the driving body driven by driving the moving element 5, and an electric pulse is generated therefrom and transmitted to the control unit 22. The control unit 22 can obtain the current position and the current speed based on this signal, and the drive frequency of the oscillation unit 21 is controlled based on the position information, the speed information, and the target position information. .

FIG. 3 is a diagram illustrating an abnormal noise suppressing member provided on the vibrating body of the ultrasonic motor according to the first embodiment.
In Example 1, the elastic body 3 of the vibrating body 1 is obtained by performing NiP surface treatment on stainless steel, and the Vickers hardness Hv is about 350. The mover 5 is obtained by subjecting aluminum to alumite surface treatment, and the Vickers hardness Hv is about 350.
In this way, the vibration body drive surface and the slider sliding surface are both hard surfaces, and when driven by friction, vibration other than the progressive vibration wave is generated in the vibration body due to chatter, etc. This can be heard as an unpleasant sound.

Therefore, in Example 1, the butyl rubber sheet 31 is attached to the piezoelectric body surface of the vibrating body 1 as an abnormal noise suppressing member to suppress vibrations other than the progressive vibration wave. By doing in this way, generation | occurrence | production of an unpleasant sound can be prevented.
Although the butyl rubber sheet 31 may be a general one, the inventors have verified that a better effect can be obtained if the Shore hardness Hs is 30 to 70.

On the other hand, when the butyl rubber sheet 31 is directly attached to the surface of the piezoelectric body 2, the effect of vibration damping is too great, and the driving vibration is also attenuated. Therefore, it is preferable to provide an intermediate layer such as a film between the surface of the piezoelectric body 2 and the butyl rubber sheet 31 so that the piezoelectric body surface and the butyl rubber sheet are not in direct contact with each other.
In this embodiment, the entire piezoelectric surface is covered with FPC (material: polyimide) 4 so that the butyl rubber sheet 31 is not in direct contact with the piezoelectric surface.

In addition, the hardness of the vibration body drive surface differs depending on whether the vibration body drive surface is in a solid stainless steel state (Hv250), a heat treatment state after NiP surface treatment (Hv500), or a titanium nitride surface treatment in a heat treatment state (Hv800). The sound prevention effect was verified, and it was found that, as in Example 1, when the butyl rubber sheet 31 was attached to the vibrating body as an abnormal noise suppressing member, unpleasant sound generated during friction driving was absorbed. .
In addition, when the mover is not alumite treated and driven with aluminum (Hv100) ground, the softness of the aluminum improves the adhesion between the surfaces and reduces the occurrence of abnormal noise. Another problem is that durability cannot be obtained.
Therefore, when the vibrator driving surface and the slider sliding surface are made of metal, it is considered that the hardness is preferably Hv 250 or more.
There is also a structure in which the piezoelectric body is pressurized from the back side through a felt or the like, but this felt has no effect of suppressing abnormal noise, and if a butyl rubber sheet is sandwiched in this structure, the vibration characteristics are significantly reduced. End up.

  FIG. 4 is a diagram illustrating an abnormal noise suppressing member provided on a vibrating body of the ultrasonic motor according to the second embodiment. In the first embodiment, the butyl rubber sheet 31 is attached to the surface of the piezoelectric body so as to reduce unpleasant noise when frictionally driven. In the second embodiment, the resin tape 32 is provided on the outer peripheral surface of the elastic body 3. To reduce unpleasant noise when friction driven. Since the structure of the vibrating body 1 and the moving element 5 is the same as that of the first embodiment, detailed description thereof is omitted.

The material of the resin tape may be any material, but silicone-based and polypropylene-based anti-vibration resins that have a small change in mechanical properties due to temperature considering driving at low temperatures and driving at high temperatures are suitable. As for the winding method, it is preferable to wind the outer circumference of the metal elastic body around the entire circumference.
As described above, when the vibrating body 1 and the moving element 5 are hard metal surfaces, when driven by friction, vibration other than the progressive vibration wave is generated in the vibrating body 1 due to chatter and the like, which is uncomfortable. It can be heard as a simple sound. One of the vibrations is a vibration having an amplitude in the radial direction. In Example 2, the vibration is suppressed by winding the resin tape 32.

(Modifications) The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
(1) Although the ultrasonic motor used in each of the above embodiments is a progressive vibration wave of four waves, the abnormal sound suppressing member is attached to the vibrating body as described above even with a progressive vibration wave of another wave number. Thus, generation of unpleasant noise can be prevented.
(2) In addition, even with an ultrasonic motor using other than the progressive vibration wave, the same effect can be obtained by mounting the noise suppressing member on the vibrating body.
(3) In the first embodiment, the elastic body 3 is described as an example in which the flange portion 3c is provided on the inner peripheral side of the base portion 3a and is fixed to the fixing member 6 (6a, 6b) using that portion. The present invention can also be applied to the case where the flange portion 3c is provided on the outer peripheral side.
(4) Moreover, although the elastic body 2 demonstrated in the example of an annular | circular shape, if it can be supported from an outer peripheral side, a cylindrical thing may be sufficient.
(5) In Example 2, although the example which stuck the resin tape 32 on the outer peripheral surface whole surface of the elastic body 3 demonstrated, you may wind only to the base part 3a. Further, the elastic body 3 may be wound around the inner periphery.
(6) In Example 1, although the example which affixes the butyl rubber sheet 31 was demonstrated, a polypropylene-type anti-vibration rubber may be sufficient.

It is a figure explaining the ultrasonic motor of Example 1 of this invention. 1 is a block diagram illustrating an ultrasonic motor driving device 20 according to a first embodiment. FIG. It is a figure explaining the abnormal noise suppression member provided in the vibrating body of the ultrasonic motor of Example 1. FIG. It is a figure explaining the abnormal noise suppression member provided in the vibrating body of the ultrasonic motor of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vibrating body 2 Piezoelectric body 3 Elastic body 3a Base part 3b Projection part 3c Flange part 4 FPC
DESCRIPTION OF SYMBOLS 5 Mover 6 (6a, 6b) Fixed member 7 Rubber member 8 Output shaft 9 Pressurizing member 10 Gear member 11 Bearing receiving member 12 Stopper 13 Bearing 21 Oscillating unit 22 Control unit 23 Phase shift unit 24, 25 Amplifying unit 26 Detection unit 31 Butyl rubber sheet 32 Resin tape

Claims (7)

A vibrating body having a piezoelectric body excited by a driving signal and an annular or cylindrical elastic body bonded to the piezoelectric body and generating a progressive vibration wave on the driving surface by the excitation;
A mover that is in pressure contact with a drive surface of the elastic body and is driven by the progressive vibration wave;
A support portion for supporting the elastic body on an inner peripheral surface and / or an outer peripheral surface;
A pressurizing unit that pressurizes the movable body via the support unit;
A vibration wave motor including
An abnormal noise suppressing member that is attached to the vibrating body and suppresses the generation of abnormal noise due to frictional driving between the vibrating body and the moving element;
Vibration wave motor characterized by The vibration wave motor according to claim 1,
The drive surface of the elastic body and the sliding surface of the moving member have a Vickers hardness Hv of 250 or more,
Vibration wave motor characterized by In the vibration wave motor according to claim 1 or 2,
A flexible printed circuit board connected to the piezoelectric body for applying a drive signal;
The abnormal noise suppressing member is mounted on the flexible printed circuit board;
Vibration wave motor characterized by In the vibration wave motor according to claim 3,
The noise suppressing member is disposed on the piezoelectric body side of the vibrating body without being in direct contact with the piezoelectric body;
Vibration wave motor characterized by In the vibration wave motor according to any one of claims 1 to 4,
The noise suppressing member is a vibration-proof rubber having a Shore hardness Hs of 30 to 70;
Vibration wave motor characterized by In the vibration wave motor according to claim 1 or 2,
The noise suppressing member is mounted on an outer peripheral surface and / or an inner peripheral surface of the vibrator;
Vibration wave motor characterized by In the vibration wave motor according to any one of claims 1, 2 and 6,
The abnormal noise suppressing member is formed of a silicone-based or polypropylene-based vibration-proof resin;
Vibration wave motor characterized by

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