JPH07337039A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To enhance reliability and stability by providing protrusions in the peripheral direction on the surface of a resilient body constituting an oscillator and a sliding member comprising a uniform resilient body in the peripheral direction on the surface of the protrusion contacting the mover thereby enhancing the drive efficiency. CONSTITUTION:A resilient body 1 is stuck to a piezoelectric ceramic 2 thus forming an oscillator 3 and protrusions 1-a are provided in the peripheral direction on the surface of the resilient body 1. A sliding member 1-b made of a resilient material having relatively low resiliency, e.g. plastic, is interposed between the protrusion 1-a and a mover 7. Since the sliding member 1-b uniform in the peripheral direction comes into direct contact with the mover 7, continuous deformation taking place on the sliding member 1-b is transmitted smoothly to the mover 7. Consequently, extreme concentration of stress on the contact face of the mover 7 is relaxed and the contact face of the mover 7 is protected against deterioration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor in which elastic vibration is generated by a piezoelectric body and the elastic vibration is used as a driving force.

[0002]

2. Description of the Related Art In recent years, attention has been paid to an ultrasonic motor that excites elastic vibration in a vibrating body formed of a piezoelectric body such as a piezoelectric ceramic and rotates a moving body using the vibrating body as a driving force.

A conventional technique of an ultrasonic motor will be described below with reference to the drawings. FIG. 18 is a sectional view of a conventional disc type ultrasonic motor. The vibrating body 3 is configured by laminating a disk-shaped piezoelectric ceramic 2 as a piezoelectric body on one of the disk surfaces of a disk-shaped elastic body 1 made of stainless steel or the like. The vibrating body 3 is held by the support body 4.

The moving body 7 is composed of a friction material 5 made of a wear-resistant material and an elastic body 6 made of stainless steel or the like, and a spring 8 pressurizes and contacts the vibrating body 3 via the friction material 5. Has been installed.

The spring 8 is fixed in a state in which a set amount of deflection is given so that a set pressing force is obtained by the retaining ring 10. A bearing 9 is arranged in order to transmit the driving force due to the elastic vibration of the vibrating body 3 to the moving body 7 without any loss.

FIG. 19 shows an example of the electrode structure of the piezoelectric ceramic 2 used in the ultrasonic motor of FIG. The drawing is designed so that elastic waves of bending vibration of primary in the radial direction and tertiary in the circumferential direction are excited.

In the figure, electrode group E (hatched display),
The electrode group F (outlined) has a length equivalent to a quarter wavelength equivalently in the circumferential direction, and is composed of small electrode portions in which the polarization directions of the electrodes adjacent to each other are opposite to the thickness direction. It is a drive electrode group. Then, the electrode groups E and F are displaced in the circumferential direction by an amount corresponding to a quarter wavelength.

In the electrode groups E and F of the piezoelectric body 2 of the ultrasonic motor configured as described above, V ₁ = V ₀ × sin (ωt) --- Formula (1) V ₂ = V ₀ × cos (ωt ) --- Equation (2) However, if V ₀ : instantaneous value of applied voltage ω: angular frequency t: V ₁ and V ₂ represented by time are respectively applied, ξ = ξ ₀ is applied to the vibrating body 3. × {cos (ωt) × cos (kx) + sin (ωt) × sin (kx)} = ξ ₀ × cos (ωt−kx) ----- Equation (3) where ξ: bending vibration amplitude value ξ ₀ : Instantaneous value of bending vibration k: Wave number (2π / λ) λ: Wavelength x: A traveling wave of bending vibration that advances in the circumferential direction represented by the position is excited.

The ultrasonic motor utilizes the fact that the moving body is driven by frictional force by this traveling wave. Therefore, in the conventional ultrasonic motor, the vibration of the vibrating body 3 is moved by the moving body 7. The surface accuracy of the contact surface between the vibrating body 3 and the moving body 7 has been increased for the purpose of efficiently transmitting the surface to the vibrating body 3.

As means for controlling the rotation speed or rotation angle of the moving body 7, a method has been adopted in which the moving body and the rotary encoder are directly connected or connected via a gear or the like and the output of the rotary encoder is used. .

[0011]

However, a plurality of protrusions arranged in the circumferential direction are provided for the purpose of enlarging the lateral movement of the elliptical locus due to the traveling wave on the surface of the vibrating body 3 and increasing the rotational speed of the moving body 7. When a body is formed, there is a problem in that the corners of the protrusions fit into the friction material 5 of the moving body 7 and hinder the smooth rotation of the moving body.

Therefore, conventionally, this corner has been rounded to obtain a smooth rotation. However, this process is inefficient and is not suitable for mass production.

Further, regarding the rotation detection of the moving body, there is a problem that the rotary encoder becomes a load and the efficiency of the ultrasonic motor is lowered.

Further, it is difficult to perform accurate position control due to a machining error of gear teeth, a meshing error of a plurality of gears, backlash, and the like, and the size of the rotation detecting portion becomes a problem.

There is also an example in which non-contact rotation speed detection using an optical sensor and a rotation detection plate is used as an encoder, but there is a problem that sensor output fluctuates greatly and accurate control cannot be performed.

An object of the present invention is to solve these problems and to provide an ultrasonic motor having high driving efficiency, high reliability and stability, and at the same time, providing an ultrasonic motor device having excellent controllability. The purpose is to do.

[0017]

[Means for Solving the Problems] By attaching a sliding member made of an elastic body, which is uniform in the circumferential direction, to the tip of a protrusion provided on a vibrating body, or by installing the sliding material by a method such as integral molding,
To realize an ultrasonic motor with high driving efficiency and high reliability, which realizes uniform contact between the vibrating body and the moving body without performing R processing on the corners of the protrusions of the vibrating body.

Further, the vibrating body is provided with an annular projection which is uniform in the circumferential direction, and a plurality of holes which are uniform in the radial direction are provided on the side surface of the projection so that the vibrating body and the moving body are made uniform. Realizes an ultrasonic motor that achieves contact, high drive efficiency, and high reliability.

Next, the side surface and the end surface of the moving body are installed on a detected body composed of a low reflection portion and a high reflection portion which are alternately formed on the side surface and the end surface in a direction perpendicular to the rotation direction, and a vibration body supporting portion for supporting the vibration body. Using the rotation information obtained by using the detector, or to extend a part of the moving body in the radial direction,
A low-reflection part and a high-reflection part, or a low-transmission part and a high-transmission part are formed alternately in the direction perpendicular to the rotation direction, and the output obtained from the detector installed on the vibrator support is used as rotation information. By doing so, a small ultrasonic motor with excellent controllability is realized.

In addition, the output signal of the rotation detecting section consisting of the optical sensor for detecting the number of rotations of the ultrasonic motor and the rotation detecting plate is a square whose amplitude maximum point and amplitude minimum point are rising and falling points. An ultrasonic motor having excellent controllability is realized by converting into a wave and performing constant velocity control using the square wave.

[0021]

The contact portion is continuous by arranging a sliding member made of an elastic body that is uniform in the circumferential direction on the tip of the projection provided on the vibrating body by bonding or by integrally molding. It becomes a face. Therefore, the surface roughness of the sliding material can be easily controlled, and even contact between the vibrating body and the moving body can be realized, and the driving force of the vibrating body can be efficiently transmitted to the moving body. A motor can be realized. Further, by reducing the thickness of the sliding member, it is possible to suppress a decrease in the amplitude of the vibrating body and an increase in the resonance frequency.

Further, the vibrating body is provided with an annular projection which is uniform in the circumferential direction, and a plurality of holes which are uniform in the radial direction are provided in the side surface of the projection so that the tip of the projection is continuous. As a result, the ultrasonic motor having high driving efficiency can be realized by efficiently transmitting the driving force of the vibrating body to the moving body. Extreme stress concentration on the contact surface of the moving body is mitigated, deterioration of the contact surface of the moving body can be prevented, and an ultrasonic motor having excellent reliability and stability can be obtained.

Next, the rotation composed of the low-reflective portion and the high-reflective portion to be detected, which are alternately formed on the side surface and the end surface of the moving body in the direction perpendicular to the rotation direction, and the detector installed on the vibrating body supporting portion. By utilizing the output of the detection unit as the rotation output, it is not necessary to newly provide a rotation detection plate, which was required in the past, and an ultrasonic motor having a small size and excellent controllability is realized. In addition, a part of the moving body is projected in the radial direction, and a low detection part and a high reflection part, or a low transmission part and a high transmission part are alternately formed on it in a direction perpendicular to the rotation direction, and the rotation detection plate and vibration By using the output of the rotation detection unit, which is a detector installed on the body support unit, as the rotation output, a compact ultrasonic motor with excellent controllability is realized. This is possible because the rotation detecting plate bears a part of the rigidity of the moving body.

In addition, a signal for controlling the rotation of the ultrasonic motor at a constant speed by feeding back the output of the rotation detecting portion composed of an optical sensor for detecting the rotational speed of the ultrasonic motor and the rotation detecting plate to the drive frequency generating portion. By using a square wave whose rising and falling points are the highest and lowest points of the output signal of the rotation detector, the output synchronized with the rotation of the ultrasonic motor is not affected by the fluctuation of the output level of the sensor. Is obtained. Therefore, by controlling the drive frequency using this output signal, it is possible to realize an ultrasonic motor with better controllability.

[0025]

【Example】

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings.

FIG. 1A is a sectional view of an ultrasonic motor according to the first embodiment of the present invention. In the figure, 1 is a disk-shaped elastic body made of stainless steel or the like, 1-a is a projection for expanding elastic waves excited on the elastic body, and 1-b is attached to the tip of the projection. It is a sliding material.

Reference numeral 2 is a disk-shaped piezoelectric ceramic, 3 is a vibrating body constructed by laminating the elastic body 1 and the piezoelectric ceramic 2, and 4 is a supporting body for supporting the vibrating body 3.

Reference numeral 5 is a friction material made of a wear-resistant material, 6 is an elastic body made of stainless steel, 7 is a moving body composed of the friction material 5 and the elastic body 6, and 8 is a friction material. 5 is a disc spring for bringing the moving body 7 into pressure contact with the vibrating body 3, 9 is a bearing installed in order to transmit the rotary motion to the moving body 7 without loss, 10 is a stop for generating a set pressing force on the disc spring 8. It is a ring. Further, FIG. 1B is a perspective cutaway view of the vibrating body 7.

Next, the effect of the same structure will be described with reference to FIG. The point A on the vibrating body 3 has a long axis 2w due to the excitation of the traveling wave,
It makes an elliptic motion of the minor axis 2u. The protrusion 1 is placed on the vibrating body 3.
By forming −a, the point B on the protrusion 1-a makes a larger elliptic motion in the lateral direction than the point A.

That is, the protrusion 1-a provided on the vibrating body 3
By placing the moving body 6 under pressure, a larger output (greater moving body speed) can be obtained as compared with the case where the moving body is placed under pressure directly on the vibrating body 3.

If the projection 1-a is continuous in the circumferential direction, the flexural rigidity of the vibrating body 3 increases,
The vibration excited on the protrusion 1-a becomes extremely small, and the speed of the moving body 7 remarkably decreases.

Therefore, in order to reduce the bending rigidity of the vibrating body 3, a configuration is adopted in which the protrusion is divided into a plurality of pieces.

However, in the same configuration, the tips of the projections attack the contact surface of the moving body, and reduce the reliability and stability of the ultrasonic motor.

Therefore, between the protrusion 1-a and the moving body 7,
A sliding member 1-b made of an elastic body having a relatively small elastic modulus such as plastic is provided. Since the sliding material 1-b, which is uniform in the circumferential direction, directly contacts the moving body 7, the sliding material 1
-Continuous deformation that occurs on top of the moving body 7
Be transmitted to.

As a result, the extreme stress concentration generated on the contact surface of the moving body can be alleviated and the contact surface of the moving body can be prevented from deteriorating, and an ultrasonic motor having excellent reliability and stability can be obtained. It was

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 3A is a sectional view of an ultrasonic motor according to the second embodiment of the present invention. In the figure, 1 is a disk-shaped elastic body made of stainless steel or the like, 1-a is a projection for expanding elastic waves excited on the elastic body, and 2 is a disk-shaped piezoelectric ceramic. Reference numeral 3 is a vibrating body configured by laminating the elastic body 1 and the piezoelectric ceramic 2.

Reference numeral 4 is a support for supporting the vibrating body 3, 5 is a friction material made of a wear-resistant material, and 6 is an elastic body made of stainless steel or the like.

Reference numeral 7 is a moving body composed of the friction material 5 and the elastic body 6, 8 is a disc spring for bringing the moving body 7 into pressure contact with the vibrating body 3 via the friction material 5, and 9 is a loss in the moving body 7. A bearing 10 installed to transmit the rotational movement is a retaining ring for generating a set pressing force on the disc spring 8.

In the same construction, the projection 1-a has a shape in which the tips are connected as shown in FIG. 3 (b). Since the protrusion 1-a having a uniform contact surface with the moving body directly contacts the moving body 7, continuous deformation occurring at the tip of the protruding body 1-a is smoothly transmitted to the moving body 7. .

As a result, the extreme stress concentration generated on the contact surface of the moving body can be alleviated and the contact surface of the moving body can be prevented from deteriorating, and an ultrasonic motor having excellent reliability and stability can be obtained. It was

(Embodiment 3) Hereinafter, Embodiment 3 of the present invention will be described with reference to the drawings.

FIG. 4 (a) is a sectional view including the protruding portion of the vibrating body according to the third embodiment of the present invention. In the figure, 1-a
Is a projection for the purpose of expanding the displacement of elastic waves excited on the elastic body, 1-b is a sliding member made of an elastic body adhered to the tip of the projection, and 1-c is 1 μm formed on the elastic body. 100μ
The slack of m is 3, and 3 is a vibrating body.

By providing the slack 1-c, it is possible to suppress an increase in equivalent bending rigidity of the vibrating body 3.

As a result, in addition to the effect of the first embodiment, the present invention can prevent the inhibition of the vibration excited by the sliding member 1-b in the vibrating body 3.

Therefore, an ultrasonic motor having excellent reliability and stability could be obtained. Although only the elastic body is provided with slack here, the same effect can be obtained by dividing the elastic body and bending it as shown in FIG. 4B.

(Embodiment 4) Hereinafter, Embodiment 4 of the present invention will be described with reference to the drawings.

FIG. 5A is a sectional view of a part of the vibrating body according to the fourth embodiment of the present invention. In the figure, 1-a is a projection for the purpose of expanding displacement of elastic waves excited on the elastic body, 1
-C is a slack of 1 μm to 100 μm formed in an elastic body, and 3 is a vibrating body.

By providing the slack 1-c, the equivalent increase in rigidity of the vibrating body 3 can be suppressed.

As a result, in addition to the effect of the second embodiment, the present invention can prevent the inhibition of the vibration excited by the vibrating body 3 by the protrusion 1-a.

Therefore, an ultrasonic motor having excellent reliability and stability could be obtained. Although only the elastic body is provided with slack in this case, the same effect can be obtained by dividing the protrusion as shown in FIG. 5 (b) and performing bending.

(Fifth Embodiment) A fifth embodiment of the present invention will be described below with reference to the drawings.

FIG. 6A is a sectional view of an ultrasonic motor device according to the fifth embodiment of the present invention. In the figure, 1 is a disk-shaped elastic body made of stainless steel or the like, 2 is a disk-shaped piezoelectric ceramic, and 3 is a vibrating body formed by laminating the elastic body 1 and the piezoelectric ceramic 2.

Reference numeral 4 is a support for supporting the vibrating body 3, 5 is a friction material made of a wear resistant material, 6 is an elastic body made of stainless steel, and 7 is a friction material 5 and an elastic body 6. And a low reflection portion 7-a on the side surface of the moving body 7.
And high-reflecting portions 7-b are formed alternately.

Reference numeral 7-c is an object to be detected which is composed of a plurality of sets of low-reflecting portions 7-a and high-reflecting portions 7-b, and 8 is a pressure contact of the moving body 7 to the vibrating body 3 via the friction material 5. Belleville springs 9 are bearings installed in order to transmit rotary motion to the moving body 7 without loss.

Reference numeral 11 denotes a rotation detector installed on the support 4 so as to face the object 7-c to be detected. Here, this detector is a reflection type detector. At the same time, FIG.
A perspective view of the moving body 7 and the detected body 7-c is shown in FIG.

7A shows the result of detecting the motion of the moving body 7 by the detected body 7-c formed on the moving body 7 and the rotation detector 11 installed on the support body 4 in the same configuration. Show.

The rotation detection result is used as motor rotation information, and the ultrasonic motor is feedback-controlled by using a drive circuit as shown in FIG. 7B to suppress variations in rotation and to achieve excellent controllability. An ultrasonic motor can be obtained.

In the figure, 21 is an ultrasonic motor, 22
Is a rotation detection unit that detects the rotation of the moving body of the ultrasonic motor 21, 23 is a voltage control circuit that outputs an AC voltage applied to the piezoelectric body of the ultrasonic motor 21, and 23- of the voltage control circuit 23.
a is a frequency control terminal, and this frequency control terminal 23-
By changing the voltage applied to a, the frequency of the drive AC signal generated in the voltage control circuit 23 can be changed.

Reference numeral 24 is a constant velocity control circuit for comparing the output signal obtained from the rotation detector 22 with the speed signal input to the rotation speed control terminal 24-a and outputting a voltage proportional to the two phase differences. .

With this configuration, it is possible to obtain a thin ultrasonic motor having a rotation detecting device, which has been difficult in the past.

Further, in this configuration, since the object to be detected is provided on the side surface of the cylindrical moving body, the distance between the rotation detector fixed to the support and the object to be detected changes.

Therefore, the point where the distance between the rotation detector and the object to be detected is the minimum is set as the detection point, and the sensor is installed so that the sensor sensitivity is maximized at that point.

As a result, it is possible to reduce the disturbance of the detector output due to the scattered light from other than the detection point.

From the above, it is possible to obtain a thin ultrasonic motor device having a highly reliable rotation detecting device and having a small number of parts because the main body and the parts of the rotation detecting device are used in common.

(Sixth Embodiment) FIG. 8A is a basic configuration diagram of the sixth embodiment. The basic configuration is the same as that of the fifth embodiment, but as the detected body of the fifth embodiment, a rotation detection plate 7-d in which a part of the moving body is projected in the radial direction is used.

On the surface of the rotation detecting plate 7-d which is perpendicular to the rotation axis of the moving body, a plurality of sets of low reflection portions 7-, which are alternately formed, are formed.
There is an object to be detected 7-c composed of a and a high-reflecting portion 7-b, and the rotation detecting portion is constituted by a reflection type rotation detector 11 installed facing the rotation detecting plate.

FIG. 8B shows a perspective view of the moving body 7 and the rotation detecting plate 7-d. With this configuration, the same effect as that of the fifth embodiment is obtained, and in addition, it also plays a role of reinforcing the moving body.

Here, although the low reflection part 7-a and the high reflection part 7-b are provided and the detector is of a reflection type, these are respectively a low transmission part, a high transmission part 7-b and a transmission type. The same effect can be obtained as a detector.

(Seventh Embodiment) A seventh embodiment of the present invention will be described below with reference to the drawings.

FIG. 9 is a drive circuit diagram of an ultrasonic motor device according to a seventh embodiment of the present invention. In the figure, 21 is an ultrasonic motor, 22 is a rotation detection unit that detects the rotation of a moving body of the ultrasonic motor 21, 23 is a voltage control circuit that generates an AC drive voltage applied to the piezoelectric body of the ultrasonic motor 21, 23-a of the voltage control circuit 23 is a frequency control terminal.

By changing the voltage applied to the frequency control terminal 23-a, the frequency of the AC drive voltage generated in the voltage control circuit 23 can be changed, and 24 is the output obtained from the rotation detecting section 22. Signal and speed control terminal 24
It is a constant speed control circuit that compares the speed signals input to -a and outputs a voltage proportional to the two phase differences.

In the same circuit, the signal output from the rotation detector 22 is shown in FIG. 10a. This output signal is interlocked with the moving body and is an output when a rotation detection plate having a plurality of sets of low-transmission parts and high-transmission parts alternately passes through a rotation detector composed of an optical sensor.

This signal has a large fluctuation in the output level and is an inappropriate signal for use in control.

Therefore, paying attention to the point that the change in the velocity of the moving body is output by the change in the phase of the output waveform, the square wave having the signal of a as the rising point and the falling point of the amplitude uppermost point and the amplitude lowermost point is used. The signal of FIG. 10b is converted into the signal of FIG. 10B. By comparing this signal with the reference signal of the rotation speed applied to the rotation speed control terminal 4-a, the rotation detection such as the fluctuation of the output level which has been a problem in the past is detected. It was possible to reduce the rotational speed control error due to part error to an extremely small level.

(Embodiment 8) An embodiment 8 of the present invention will be described below with reference to the drawings.

FIG. 11 is a circuit block diagram of the eighth embodiment of the present invention. In the figure, 22 is a rotation detector for detecting the rotation of the moving body, 25 is a differentiating circuit for differentiating and outputting the input waveform, 26 is a comparator, and 27 is a motor drive control circuit.

In the same circuit, the signal output from the rotation detector 22 is shown in FIG. 12a. This signal is output when a rotation detection plate having a plurality of sets of low-transmission parts and high-transmission parts alternately passes through a rotation detector composed of an optical sensor, which moves in conjunction with the moving body.

This signal has a large variation in the output level and is unsuitable for use in control.

Therefore, this signal is converted into a square wave having its uppermost point and its lowermost point of rising and falling points.

First, the output signal a of the rotation detector 22 is first.
Is input to the differentiating circuit 25 to differentiate.

The output signal is shown in FIG. 12b. This signal is a signal whose output is always 0 at the peak point of the signal a.

Next, the signal b is input to the comparator 26 whose cut voltage is set to the ground level, and the signal shown in FIG.
As shown in, the maximum amplitude and the minimum amplitude are the rising points,
Get the square wave that is the falling point.

By performing drive control using this signal c, the rotation speed control error due to the error of the rotation detection unit such as the fluctuation of the output level, which has been a problem in the related art, can be made extremely small.

(Ninth Embodiment) A ninth embodiment of the present invention will be described below with reference to the drawings.

FIG. 13 is a circuit block diagram of the ninth embodiment of the present invention. In the figure, 22 is a rotation detection unit that detects the rotation of the moving body, 28 is a full-wave rectification circuit, 29 is a peak hold circuit, 26 is a comparator, 30 is a counter that performs frequency division processing, and 27 is a drive control of the motor. It is a drive control circuit.

In the same circuit, the signal output from the rotation detector 22 is shown in FIG. 14a. This signal is output when a rotation detection plate having a plurality of sets of low-transmission parts and high-transmission parts alternately passes through a rotation detector composed of an optical sensor, which moves in conjunction with the moving body.

This signal has a large fluctuation in the output level and is unsuitable for use in control.

Therefore, this signal is converted into a square wave having its uppermost point and its lowermost point of rising and falling points.

First, the output signal a of the rotation detector 22
Is input to the full-wave rectifier circuit 28 to perform full-wave rectification. The output signal is shown in FIG. 14b.

Next, this b signal is applied to the peak hold circuit 2
Enter in 9. This circuit detects the rising portion of the input signal b. The output signal of this circuit is FIG. 14c.

Then, the signals b and c are input to the comparator 26 which is a comparison circuit. As a result, the digital signal d obtained by detecting the rising portion of the signal b is obtained.

Finally, by inputting the signal d to the counter and performing frequency division processing, a square wave having the rising and falling points as the uppermost and lowermost points of the signal a output from the rotation detecting section is obtained. To get

By performing drive control using this signal e, the rotational speed control error due to the error of the rotation detecting unit such as the fluctuation of the output level, which has been a problem in the related art, can be made extremely small.

Example 10 Hereinafter, Example 10 of the present invention will be described.
Will be described with reference to the drawings.

FIG. 15A is a circuit block diagram of the tenth embodiment of the present invention. In the figure, 22 is a rotation detecting section for detecting the rotation of the moving body, 31 is a digital processing section for calculating and outputting the input waveform, and 27 is a motor drive control circuit. The digitization processing unit is a signal generation unit 31-a that generates a signal and a CPU that controls the signal generation unit 31-a.
31-b.

The operation of the digitization processing unit in the circuit block will be briefly described. In this processing unit, the CPU detects the peak position of the input signal from the rotation detection unit, and at that time, switches the switch of the signal generation unit that changes the signal from the High level to the Low level and from the Low level to the High level. .

As a result, the analog signal input from the rotation detecting section is converted into a square wave whose rising and falling points are the maximum amplitude point and the minimum amplitude point. In addition, a simple signal processing unit 3 is shown in FIG.
An example of 1-a is shown.

FIG. 16 is a flow chart executed in the CPU. The operation will be briefly described below with reference to the flowcharts.

First, initialize [switch command variable (S)
Low, comparison signal level (C0) to 0, elapsed time (tim
e) is set to 0. Sampling time (ST) setting. ]
I do.

Next, the sampling time is counted.
Next, the input rotation signal level C and the comparison signal C0
Make a comparison. Here, when C0> C is not established, C is substituted for C0, and the sampling time is counted again.

When the condition is satisfied, the switch variable S is switched to High and a switch command is output. Next, the input rotation signal level C and the comparison signal C0 are compared.

If C0 <C is not satisfied, then C0 is replaced by C
And returns to the sampling time count again. If the condition is satisfied, the switch variable S is switched to Low, a switch command is output, and the process returns to counting the sampling time.

By the above processing, as shown in FIG. 17, it is possible to obtain the square wave b having the maximum amplitude point and the minimum amplitude point of the signal a output from the rotation detecting section as the rising and falling points. It was By performing drive control using this digital signal, the rotational speed control error due to the error of the rotation detection unit such as the fluctuation of the output level, which has been a problem in the past, could be made extremely small.

[0105]

According to the present invention, it is possible to realize an ultrasonic motor which can prevent deterioration of the contact surface of a moving body, has high driving efficiency, and is excellent in reliability and stability. In addition, it is possible to obtain an ultrasonic motor device with excellent controllability that suppresses variations in rotation.

[Brief description of drawings]

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

[Fig. 2] Operating principle diagram of ultrasonic motor

FIG. 3 is a configuration diagram of an ultrasonic motor according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a vibrating body according to a third embodiment of the ultrasonic motor of the present invention.

FIG. 5 is a sectional view of a vibrating body according to a fourth embodiment of the ultrasonic motor of the present invention.

FIG. 6 is a configuration diagram of a fifth embodiment of an ultrasonic motor according to the present invention.

FIG. 7 is an explanatory diagram of rotation control in Embodiment 5 of the ultrasonic motor according to the present invention.

FIG. 8 is a configuration diagram of an ultrasonic motor according to a sixth embodiment of the present invention.

FIG. 9 is a drive circuit configuration diagram of an ultrasonic motor device according to a seventh embodiment of the present invention.

FIG. 10 is an explanatory diagram of rotation detection in the configuration of Embodiment 7 of the ultrasonic motor device of the present invention.

FIG. 11 is a control block diagram of an eighth embodiment of the ultrasonic motor device of the present invention.

FIG. 12 is an explanatory diagram of rotation detection in the configuration of Embodiment 8 of the ultrasonic motor device of the present invention.

FIG. 13 is a control block diagram of an ultrasonic motor device according to a ninth embodiment of the present invention.

FIG. 14 is an explanatory diagram of rotation detection in the configuration of Embodiment 9 of the ultrasonic motor device of the present invention.

FIG. 15 is a control explanatory view of the ultrasonic motor device according to the tenth embodiment of the present invention.

FIG. 16C of Example 10 of the ultrasonic motor device of the present invention
Flowchart diagram of processing in PU

FIG. 17 is an explanatory diagram of rotation detection according to the tenth embodiment of the ultrasonic motor device of the present invention.

FIG. 18 is a sectional view of a conventional disc type ultrasonic motor.

FIG. 19 is an electrode structure diagram of a piezoelectric ceramic used in an ultrasonic motor.

[Explanation of symbols]

 1 Elastic body 1-a Projection body 1-b Sliding material 1-c Sagging 2 Piezoelectric ceramic 3 Vibrating body 4 Support body 5 Friction material 6 Elastic body 7 Moving body 7-a Low reflection part (low transmission part) 7-b High reflection part (high transmission part) 7-c Detected object 7-d Rotation detection plate 8 Spring 9 Bearing 10 Retaining ring 11 Rotation detector 21 Ultrasonic motor 22 Rotation detection part 23 Voltage control circuit 23-a Frequency control terminal 24 Constant speed control circuit 24-a Rotation speed control terminal 25 Differentiation circuit 26 Comparator 27 Drive control circuit 28 Full wave control circuit 29 Peak hold circuit 30 Counter 31 Digitization processing 31-a Signal generation unit 31-b CPU

Front page continuation (72) Inventor Katsushi Takeda 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Takahiro Nishikura 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial (72) Invention Person Masanori Sumihara 1006, Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Tetsuro Ochi 1006, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 1006 Kadoma, Oita-shi Matsushita Electric Industrial Co., Ltd.

Claims (10)

[Claims] 1. A piezoelectric body is driven by an alternating voltage to excite an elastic traveling wave in a vibrating body composed of the piezoelectric body and an elastic body, so that the vibrating body is brought into pressure contact with a vibrating mechanism. In the ultrasonic motor device configured to move a moving body installed in a vertical direction, a plurality of protrusions are provided in a circumferential direction on the elastic body surface that constitutes the vibrating body, and the protrusions come into contact with the moving body. An ultrasonic motor device characterized in that a sliding member made of an elastic body is provided on the surface in the circumferential direction. 2. The ultrasonic motor device according to claim 1, wherein a portion of the sliding member other than the protrusion has slack. 3. A piezoelectric body is driven by an alternating voltage to excite an elastic traveling wave in a vibrating body composed of the piezoelectric body and an elastic body, so that the vibrating body is brought into pressure contact with the vibrating body. In an ultrasonic motor device configured to move a moving body installed as a ring, a uniform annular projection is provided in a circumferential direction on the elastic body surface forming the vibrating body, and a radius is provided on a side surface of the projection. An ultrasonic motor device characterized in that a plurality of holes which are uniform in direction are provided. 4. The ultrasonic motor device according to claim 3, wherein the upper portion of the hole provided in the annular projection has a gentle slack. 5. A piezoelectric body is driven by an alternating voltage to excite an elastic traveling wave in a vibrating body composed of the piezoelectric body and an elastic body so that the vibrating body is brought into pressure contact with the vibrating body. In an ultrasonic motor device configured to move a moving body that is installed as a support, the moving body is supported on the detected body in which a low reflection portion and a high reflection portion are alternately formed on a side surface or an end surface of the movement body. An ultrasonic motor device, comprising: a rotation detection unit including a detector installed on a support base. 6. The ultrasonic motor device according to claim 5, wherein a radial projection is formed on a part of the moving body as the detected body, and the projecting body is perpendicular to the rotation axis of the moving body. An ultrasonic motor device characterized in that a low-reflection portion and a high-reflection portion or a low-transmission portion and a high-transmission portion are formed on a flat surface. 7. A piezoelectric body is driven by an alternating voltage to excite an elastic traveling wave in a vibrating body composed of the piezoelectric body and an elastic body so that the vibrating body is brought into pressure contact with the vibrating body. In an ultrasonic motor device composed of a moving body installed as a unit and a rotation detecting section for detecting the rotation of the moving body, the frequency can be varied by controlling the voltage applied to the frequency control terminal. A voltage control drive circuit that generates an AC voltage for driving the body, and a square wave having a rising point and a falling point as the uppermost point and the lowermost point of the amplitude of the signal output from the rotation detection unit. The phase difference between the square wave and the rotation reference signal is detected by comparing with the signal, and the output oscillation frequency of the voltage control drive circuit is applied to the frequency control terminal so that the phase difference becomes a predetermined value. By voltage Ultrasonic motor apparatus characterized by comprising a constant speed control circuit Gosuru. 8. The ultrasonic motor device according to claim 7, wherein as means for creating a square wave having a rising point and a falling point as the uppermost amplitude point and the lowermost amplitude point of the signal output from the rotation detecting section, An ultrasonic motor device characterized by using a differentiating circuit. 9. The ultrasonic motor device according to claim 7, wherein a peak is generated as a means for creating a square wave whose rising and falling points are the uppermost amplitude point and the lowermost amplitude point of the signal output from the rotation detecting section. An ultrasonic motor device characterized by using a hold circuit. 10. The ultrasonic motor device according to claim 7, which is operated as a means for creating a square wave having an amplitude maximum point and an amplitude minimum point of a signal output from a rotation detecting section as rising and falling points. The ultrasonic motor device according to claim 7, wherein a processing device is used.