JP2003244975A - Oscillatory wave motor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oscillatory wave motor and its manufacturing method by which the shift amount of a driving frequency band is controlled and an assembly adjustment cost is reduced. <P>SOLUTION: The motor includes a vibrator 11, which has a piezoelectric material 13 excited by a driving signal and an elastic body 12 that is joined to the piezoelectric material 13 and that generates a progressive oscillatory wave by excitation on a driving surface 12c opposite to a surface to which the piezoelectric material 13 is joined, and a mover 17 which is pressed and brought into contact with the driving surface 12c and is driven by the progressive oscillatory wave, wherein the elastic body 12 has a groove 12a at the driving surface side 12c, and the groove 12a includes a curved shape 12d formed a the corner of a bottom 12a-1 and a protruded portion 12e protruded and formed at the center of the bottom 12a-1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration wave motor having an elastic body having a groove and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as is known in Japanese Patent Publication No. 17354/1989, this type of vibration wave motor utilizes the expansion and contraction of a piezoelectric body to generate a progressive vibration wave on the drive surface of an elastic body. The traveling wave causes an elliptical motion on the driving surface, and the moving element that is in pressure contact with the wave front of the elliptic motion is driven. Since such a vibration wave motor has a characteristic that it has a high torque even at a low rotation speed, when it is mounted on a drive device, the gear of the drive device can be omitted, so that gear noise is eliminated and positioning accuracy is improved. Can be improved.

A vibrator of a vibration wave motor using such a traveling traveling wave is composed of a piezoelectric body and an elastic body, and the piezoelectric body and the elastic body are firmly adhered by an adhesive or the like. ing. Further, the elastic body is provided with grooves of equal width and substantially equal intervals on the drive surface side opposite to the piezoelectric body joint surface. Due to this groove, the neutral surface of the bending vibration of the elastic body is shifted to the piezoelectric body side, whereby the amplitude of the progressive vibration wave on the drive surface side is expanded.

The progressive vibration wave generated in this elastic body is obtained by synthesizing two standing waves of bending vibration generated by the excitation of the piezoelectric body. The value of the resonance frequency of the standing wave of this bending vibration is, when the order of vibration and the outer and inner diameters are fixed,
It mainly corresponds to the thickness of the elastic body, in particular, the thickness of the bottom of the elastic body. For example, as the thickness of the bottom portion becomes thicker, the resonance frequency of the standing wave of bending vibration becomes higher, and accordingly, the driving frequency band of the vibration wave motor shifts to a higher frequency. Further, when the thickness of the bottom portion becomes thin, the resonance frequency of the standing wave of bending vibration becomes low, and accordingly, the driving frequency band of the vibration wave motor shifts to a lower frequency.

Most of the speed control of the vibration wave motor is performed by changing the frequency. In order to perform speed control accurately, it is necessary to inspect and adjust the relationship between speed and frequency such as the frequency of zero speed, the frequency of a certain speed, the frequency of maximum speed, etc. for each motor. Therefore, when the shift amount of the drive frequency band is larger than the individual difference of the vibration wave motor, man-hours are required to find an appropriate drive frequency band.

Further, if the shift amount of the drive frequency band is large, the oscillation unit of the drive circuit may not be able to handle the shift amount. Therefore, it is necessary to prepare several oscillating units having different frequency bands and select the oscillating units according to the shift amount of the bands, which causes a problem that the process becomes complicated. Therefore, it is necessary to suppress the variation in the thickness of the bottom portion and reduce the shift amount of the driving frequency band in order to prevent the increase in the number of steps and the complexity of the process as described above and the increase in cost.

[0007]

However, in the conventional vibration wave motor described above, the groove portion of the elastic body is usually processed by a milling machine or the like, and about 40 to 80 per elastic body. The existing grooves are processed one by one, and the frequency of use of the cutting tool in the groove processing is very high. Therefore, while processing a number of elastic bodies, the ends of the cutting tool are worn away, and R-shapes occur at the corners of the bottom. For example, when performing groove processing with one bite, the first elastic body has no R shape at the corner of the groove, but a small R shape is attached to the corner of the groove of the second elastic body, A large R shape is formed at the corner of the groove of the tens of elastic body. On the other hand, in the processing using the rotating grindstone, the stress concentrates on the outer peripheral edge, so that the rotating grindstone itself is easily worn, and the R shape is likely to occur at the corner of the bottom.

FIG. 10 is a graph showing the relationship between the R shape of the corner portion of the bottom and the resonance frequency of bending vibration when the cross section in the circumferential direction of the bottom is viewed. It can be seen that as the R shape of the corner becomes larger, the frequency changes to the higher side in a quadratic curve. As described above, there has been a phenomenon that the drive frequency band of the vibration wave motor is increased with the number of machining of the cutting tool. When the drive frequency band is greatly different between the individual motors, as described above, a process is required to find the drive frequency band itself, or the process of selecting the oscillator section of the drive circuit by dividing it into several types. However, there is a problem in that it becomes complicated.

It is an object of the present invention to provide a vibration wave motor in which the amount of shift in the drive frequency band is suppressed and the cost of assembly and adjustment is reduced, and a method for manufacturing the same.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 is joined to a piezoelectric body excited by a drive signal and the piezoelectric body, and the piezoelectric body is joined by the excitation. A vibrator having an elastic body that generates a progressive vibration wave on a drive surface opposite to the surface; a mover that is brought into pressure contact with the drive surface and is driven by the progressive vibration wave;
In the vibration wave motor including, the elastic body includes a groove portion on the drive surface, the groove portion, a curved portion formed in a corner portion of the bottom portion, and a raised portion formed in the central portion of the bottom portion. Is a vibration wave motor.

According to a second aspect of the invention, in the vibration wave motor according to the first aspect, the elastic body has an annular shape, and the groove portion extends in a radial direction with respect to the annular ring. The shape portion and the raised portion extend in the radial direction, and the curved shape portion is a smooth concave surface portion connecting the bottom portion and a wall portion extending from the drive surface to the bottom portion. Is a vibration wave motor.

The invention according to claim 3 is claim 1 or claim 2.
In the vibration wave motor according to [1], Rx is larger than Rz, where Rx is the circumferential length of the curved portion and Rz is the height of the groove portion in the depth direction of the curved portion. , Is a vibration wave motor. According to a fourth aspect of the invention, in the vibration wave motor according to the third aspect, the R
The relation between z and Rx is Rz: Rx = 1: 2 to 2: 3.
Is a vibration wave motor.
According to a fifth aspect of the present invention, in the vibration wave motor according to the first or second aspect, the circumferential length of the curved portion is Rx.
And a ratio of Rx: tr = 100: 4 to 10: 4, where tr is the height of the raised portion from the bottom portion.

The invention of claim 6 is from claim 1 to claim 5.
In the vibration wave motor according to any one of items 1 to 4, the bottom portion includes an inflection portion between the curved portion and the raised portion, which is a vibration wave motor.

The invention of claim 7 is from claim 1 to claim 6.
The method of manufacturing a vibration wave motor according to any one of 1 to 3, wherein the vibration wave motor has a disk shape, and the end of the disk-shaped outer peripheral surface is a smooth surface, and A method of manufacturing a vibration wave motor, comprising: a processing step of processing a groove portion of the elastic body with a grindstone having a circumferential recess.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a vibration wave motor according to the present invention will be described in detail below with reference to the accompanying drawings. Note that the following embodiments will be described by taking an ultrasonic motor that utilizes the vibration range of ultrasonic waves as an example of the vibration wave motor. FIG. 1 is a diagram illustrating an ultrasonic motor 10 according to an embodiment of the present invention. FIG. 2 is an external perspective view showing the vibrator 11 and the mover 17 of the ultrasonic motor 10 of this embodiment.

The ultrasonic motor 10 of this embodiment is provided with a vibrator 11 and a mover 17, and the vibrator 11 side is fixed,
The moving element (relative movement member) 17 side is rotationally driven. The buffer member 1 is provided below the vibrator 11.
4, the pressure plate 15, the pressure member 16, and the support member 19A are arranged, and the vibration absorbing member 18 and the rotation member 19B are arranged above the moving element 17.

The vibrator 11 includes an elastic body 12 and an elastic body 12
And an electromechanical conversion element (hereinafter, referred to as a piezoelectric body) 13 which is an example of a piezoelectric element or an electrostrictive element for converting electric energy to mechanical energy which will be described later. Although a traveling wave is generated in the vibrating body 11, in the present embodiment, as an example, a traveling wave of nine waves will be described.

The elastic body 12 is made of a metal material having a large resonance sharpness, and its shape is an annular shape. The elastic body 12 has a groove 12a cut on the opposite surface to which the piezoelectric body 13 is bonded, and a protrusion (a portion where the groove 12a is not provided) 1
The front end surface of 2b serves as the drive surface 12c and is brought into pressure contact with the mover 17. The reason for cutting the groove 12a is to bring the neutral surface of the traveling wave closer to the piezoelectric body 13 side as much as possible, thereby amplifying the amplitude of the traveling wave of the driving surface 12c.

The piezoelectric body 13 is divided into two phases (A phase and B phase) along the circumferential direction, and in each phase, 1 /
Elements with alternating polarization for every two wavelengths are arranged,
There is a quarter wavelength interval between the A phase and the B phase.

Below the piezoelectric body 13, a buffer member 14, a pressure plate 15, a pressure member 16 and a support member 19A are arranged. The cushioning member 14 is disposed below the piezoelectric body 13 and is a member for preventing the vibration of the vibrator 11 from being transmitted to the pressure plate 15 and the pressure member 16. For example, a non-woven fabric or felt is used. ing. The pressure plate 15 is a plate for receiving pressure from the pressure member 16. The pressure member 16 is
It is a member that is arranged under the pressure plate 15 and generates a pressing force. In the present embodiment, the pressing member 16 is a disc spring, but a coil spring or a wave spring may be used instead of the disc spring. The support member 19A is the ultrasonic motor 10
Is a member that supports on the fixed side.

The mover 17 is made of a light metal such as aluminum, and the surface of the sliding surface 17a is surface-treated to improve wear resistance. Above this mover 17,
In order to absorb the vibration of the mover 17 in the pressing direction, a vibration absorbing member 18 such as rubber is arranged, on which a rotating member 19B such as a bearing is arranged.

FIG. 3 is a block diagram for explaining the drive control device 20 for the ultrasonic motor according to this embodiment. First,
The configuration of the drive control device 20 for the ultrasonic motor will be described. The drive control device 20 includes an oscillator 21, a controller 22,
The phase shift unit 23, the amplification units 24 and 25, the detection unit 26, and the like are provided.

The oscillator 21 receives a command from the controller 22,
A drive signal having a desired frequency is generated. The phase shift unit 23 divides the drive signal generated by the oscillator 21 into two drive signals having 90 ° different phases. The amplifiers 24 and 25 are the phase shifter 23.
Each of the two drive signals divided by is boosted to a desired voltage. The drive signals from the amplifiers 24 and 25 are
The traveling wave is transmitted to the ultrasonic motor 10 and the traveling wave is generated in the vibrating body 11 by the application of the drive signal, and the moving element 17 is driven. The detection unit 26 is composed of an optical linear encoder or the like, and detects the position and speed of a driven body (not shown) driven by driving the moving element 17.

The control unit 22 controls the drive of the ultrasonic motor 10 based on the drive command from the CPU. And
The control unit 22 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 oscillator 21 so that the oscillator 21 is positioned at the target position.

Next, the operation of the ultrasonic motor drive controller 20 of this embodiment will be described. First, the target position is transmitted to the control unit 22. A drive signal is generated from the oscillating unit 21, the signal is divided into two drive signals having a 90 ° phase difference by the phase shift unit 23, and the amplifying units 24 and 25
It is amplified to the desired voltage. The drive signal is the ultrasonic motor 1
0 is applied to the piezoelectric body 13, the piezoelectric body 13 is excited,
Due to the excitation, a ninth-order bending vibration is generated in the elastic body 12. The piezoelectric body 13 is divided into an A phase and a B phase, and drive signals are applied to the A phase and the B phase, respectively. A
The 9th-order bending vibration generated from the phase and the 9th-order bending vibration generated from the B-phase are such that the positional phases are shifted by ¼ wavelength, and the A-phase drive signal and the B-phase drive signal are different from each other. , 9
Since the phase is 0 ° out of phase, two bending vibrations are combined into nine traveling waves.

The traveling wave has an elliptical motion at its wave front. Therefore, since the moving element 17 is in pressure contact with the driving surface 12c, it is frictionally driven by this elliptic movement. The detection unit 26 is arranged on the driven body driven by the drive of the moving element 17, and the electric pulse signal generated from the detection unit 26 is transmitted to the control unit 22. Control unit 22
Can obtain the current position and the current speed based on this signal, and controls the drive frequency of the oscillator 21 based on the position information, the speed information, and the target position information.

FIG. 4 is a view for explaining the shape of the bottom of the elastic body of the ultrasonic motor according to this embodiment. In the present embodiment, the elastic body 12 includes the groove 12a on the drive surface 12c side. The groove portions 12a are provided at equal intervals and equal widths along the circumferential direction, and 54 grooves are provided. The curved portions 12d formed at the corners of the bottom portion 12a-1 and the central portion of the bottom portion 12a-1 have high heights. It has a raised portion 12e that is raised in a convex shape having a length tr. As shown in FIG. 2, the elastic body 12 has an annular shape, and the groove portion 12a extends in the radial direction with respect to the annular shape. The curved portion 12d and the raised portion 12e are also
Similarly, it extends in its radial direction. The curved portion 12d is a smooth concave surface portion that connects the bottom portion 12a-1 and the wall portion 12f extending from the drive surface 12c to the bottom portion 12a-1. The bottom portion 12a-1 includes a curved portion 12d and an inflection portion 12f of a raised portion 12e. When the curved portion 12d has a length Rx in the circumferential direction and the height of the groove 12a in the depth direction is Rz, Rx is larger than Rz. According to an experiment by the inventor of the present application, Rz: Rx =
It has been found that a ratio of 1: 2 to 2: 3 is preferable.

Since the groove is formed so as to have the above-mentioned shape, the fluctuation of the resonance frequency of the elastic body is reduced when the groove is continuously formed. Specifically, the shift amount between the resonance frequency of the first elastic body and the resonance frequency of the tens of the elastic body is reduced.

FIG. 5 is a diagram showing the groove processing method according to the present embodiment. The groove processing step is preferably performed with the grindstone 30. In the grindstone 30, the binder is resin and the abrasive grains are CB.
N # 170 is preferably used. This whetstone 30
Performs groove processing by dressing in a shape compatible with the groove shape described above. That is, as shown in FIG. 5, the grindstone 30 has a disc shape, the end portion 31 of the outer peripheral surface of the disc shape is a smooth surface, and the peripheral concave portion 32 is provided in the central portion of the outer peripheral surface.

FIG. 6 is a diagram showing changes in the values Rz, Rx, and tr indicating the shape of the bottom when grooves are continuously processed with a grindstone. In FIG. 6, the Rx value gradually increases as the number of continuous machining increases, and the length tr in the depth direction of the raised portion 12e at the central portion increases. At this time, the Rz value has not changed much. From this, it can be said that the grindstone wears most severely when grooving.
It can be seen that there are a corner portion (corresponding to the position of Rx) of the tip surface and a central portion (corresponding to the position of tr) of the tip surface.

Here, when the groove is continuously processed, the Rx value gradually increases, and the convex portion at the central portion increases, and whether this is related to the reduction of the frequency fluctuation of the elastic body, The results of investigation using the prototypes (Comparative Examples 1 to 3) will be described with reference to FIGS. 7 to 9.

FIG. 7 shows the Rz value (Rx value = 0.
Prototype of the relationship between 1mm constant) and resonance frequency (Comparative Example 1)
It is the result of the investigation using. When the Rz value increases,
It can be seen that the resonance frequency value is large.

FIG. 8 shows the Rx value (Rz value = 0.
Prototype of the relationship between 1mm constant) and resonance frequency (Comparative example 2)
It is the result of the investigation using. When the Rz value increases,
It can be seen that although the resonance frequency value is large, the amount of change is smaller than the change in the Rz value.

FIG. 9 shows the value tr of the convex ridge in the central portion.
It is the result of investigating the relationship between the value and the resonance frequency using a prototype (Comparative Example 3). It can be seen that the resonance frequency value decreases as the tr value increases.

From these results, the Rx value and the resonance frequency have a positive relationship in which the resonance frequency increases as the Rx value increases, and the tr value and the resonance frequency indicate that the resonance frequency decreases in the negative direction as the tr value increases. It is found that they have a relationship and cancel the frequency fluctuations with each other. Further, in the present embodiment, the Rx value is set to be larger than the Rz value.
The fluctuation of the value is small, and the fluctuation of the resonance frequency can be reduced.

In this embodiment, the Rx value is 0.10.
The range of ˜0.25 mm is preferable, and the Rz value is 0.05.
The range of 0.15 mm is preferable, and the tr value is 0.00.
A range of 1 to 0.04 mm is suitable. Therefore, when the circumferential length of the curved portion is Rx and the height of the raised portion from the bottom is tr, Rx: tr = 10.
The ratio is preferably 0: 4 to 10: 4.

As described above, according to the present embodiment, the groove portion has a circumferential length Rx larger than the depth-direction length Rz of the curved portion, and a convex ridge portion at the center. Since the shape of the bottom portion is provided, the fluctuation of the resonance frequency of the standing wave of the bending vibration due to the continuous processing is reduced. As a result, the ultrasonic motor can reduce the individual difference in the shift amount of the drive frequency band. Therefore, it was possible to omit the step of searching for a frequency band that was necessary during assembly and adjustment. In addition, it is no longer necessary to prepare several oscillating units having different frequency bands as in the past and to select the oscillating units according to the shift amount of the frequency band, thereby achieving cost reduction. Further, in order to make the shape of the corner of the bottom constant, conventionally, the number of continuous processing of the cutting tool or the grindstone was limited to about several tens, but in the present embodiment, the number of continuous processing can be increased. Became. For example, even if the grindstone is more expensive than the cutting tool of the milling machine, the number of times of machining can be increased, and as a result, the manufacturing cost can be reduced.

On the other hand, since the corners of the bottom are preliminarily R-shaped (curved portion), even if a rotating grindstone is used, the stress is dispersed without concentrating on the outer peripheral edge, so the wear of the grindstone itself is It was extremely low. That is, if the bottom corners are not rounded, stress concentrates on the outer peripheral edge of the grindstone during processing, and the grindstone itself wears. However, by providing the R shape, stress concentration during processing can be prevented and deformation due to wear of the grindstone itself can be reduced. For this reason, the shape of the corner of the bottom was stable even when the rotary grindstone was used, and the shape change was small even when continuous processing was performed. As a result of using such a grindstone, in the elastic body, a convex ridge is formed in the center of the groove, so that even if the shape of the bottom corner changes, the fluctuation of the resonance frequency becomes small.

The present invention is not limited to the embodiment described above, and various modifications and changes can be made, which are also within the scope of the present invention. For example, the ultrasonic motor used in the present embodiment has been described by taking an elastic body having 54 grooves as a progressive vibration wave of 9 waves as an example. Even if the number of grooves is 3, the ultrasonic motor using the progressive vibration wave can be similarly applied and the same effect can be obtained.

Further, the curved portion formed at the corner of the bottom and the raised portion formed at the center of the bottom in the circumferential cross section of the groove portion of the elastic body described above have been described in the example processed with a grindstone. This shape also has the same effect when press working.

[0041]

As described above in detail, according to the present invention, the elastic body is provided with the groove portion on the driving surface, and the groove portion has the curved portion formed at the corner of the bottom portion and the center of the bottom portion. Since there is a raised portion formed in the portion, the fluctuation of the resonance frequency of the standing wave of the bending vibration due to continuous processing is reduced.
As a result, the ultrasonic motor can reduce the individual difference in the shift amount of the drive frequency band. Further, since the bottom of the groove has a predetermined shape, it is possible to increase the number of continuous grindstone processes.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an ultrasonic motor 10 according to an embodiment of the present invention.

FIG. 2 is an external perspective view showing a vibrator 11 and a mover 17 of the ultrasonic motor 10 of this embodiment.

FIG. 3 is a block diagram illustrating an ultrasonic motor drive controller 20 according to the present embodiment.

FIG. 4 is a diagram illustrating a shape of a bottom portion of an elastic body of the ultrasonic motor according to the present embodiment.

FIG. 5 is a diagram showing the method of manufacturing the ultrasonic motor according to the present embodiment.

FIG. 6 is a diagram showing changes in the values Rz, Rx, and tr indicating the bottom shape when the grooves of the ultrasonic motor are continuously grooved by a grindstone.

FIG. 7: Rz value of curved portion (Rx value = 0.1 mm constant)
FIG. 5 is a diagram showing the results of investigating the relationship between the resonance frequency and the resonance frequency using a prototype (Comparative Example 1).

FIG. 8: Rx value of curved portion (Rz value = 0.1 mm constant)
6 is a diagram showing the results of an investigation of the relationship between the resonance frequency and the resonance frequency using a prototype (Comparative Example 2).

FIG. 9 is a diagram showing the results of an investigation of the relationship between the tr value of a convex ridge in the center and the resonance frequency using a prototype (Comparative Example 3).

FIG. 10 is a diagram showing the relationship between the R shape of the corner of the bottom and the resonance frequency of bending vibration when the circumferential cross section of the bottom is viewed.

[Explanation of symbols]

10 Ultrasonic motor 11 oscillators 12 Elastic body 12a groove 12b protrusion 12c drive surface 12d curved part 12e Raised part 13 Piezoelectric body 14 Buffer member 15 Pressure plate 16 Pressure member 17 mover 18 Vibration absorbing member 19A support member 19B rotating member 20 Drive controller 21 Oscillator 22 Control unit 23 Phase shift unit 24,25 amplifier 26 Detector

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ryoichi Suganuma             Marunouchi 3 2-3 No. 3 shares, Chiyoda-ku, Tokyo             Ceremony Company Nikon F-term (reference) 5H680 AA10 BB03 BB17 CC02 CC07                       DD02 DD13 DD23 DD35 DD53                       DD65 DD66 DD75 DD87 FF13                       FF14 GG25 GG42

Claims (7)

[Claims] 1. A piezoelectric body that is excited by a drive signal, and an elastic body that is joined to the piezoelectric body and that produces a progressive vibration wave on a drive surface opposite to a surface where the piezoelectric body is joined by the excitation. In a vibration wave motor including: a vibrator; and a mover that is brought into pressure contact with the drive surface and driven by the progressive vibration wave, the elastic body includes a groove portion on the drive surface, and the groove portion includes: Having a curved portion formed at a corner of the bottom portion and a raised portion formed at the center of the bottom portion,
Vibration wave motor characterized by. 2. The vibration wave motor according to claim 1, wherein the elastic body has an annular shape, the groove portion extends in a radial direction with respect to the annular ring, and the curved shape portion and the ridge are provided. The portion extends in the radial direction, and the curved portion is a smooth concave surface portion that connects the bottom portion and a wall portion that extends from the drive surface to the bottom portion. . 3. The vibration wave motor according to claim 1 or 2, wherein the circumferential length of the curved portion is Rx, and the height of the groove portion of the curved portion in the depth direction is Rz. In this case, the vibration wave motor is characterized in that Rx is made larger than Rz. 4. The vibration wave motor according to claim 3, wherein the relationship between the Rz and the Rx is Rz: Rx = 1: 2.
A vibration wave motor having a ratio of 2: 3. 5. The vibration wave motor according to claim 1 or 2, wherein the circumferential length of the curved portion is Rx, and the height of the raised portion from the bottom is tr. , Rx: tr =
A vibration wave motor having a ratio of 100: 4 to 10: 4. 6. Any one of claims 1 to 5
The vibration wave motor according to the item 1, wherein the bottom portion includes an inflection portion of the curved portion and the raised portion. 7. Any one of claims 1 to 6
In the method for manufacturing a vibration wave motor for manufacturing a vibration wave motor according to the item, a disk shape is provided, and an end portion of the disk-shaped outer peripheral surface is a smooth surface, and a peripheral concave portion is provided at a central portion of the outer peripheral surface. A method of manufacturing a vibration wave motor, comprising a processing step of processing the groove portion of the elastic body with a grindstone.