JPH089666A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To drive individual piezoelectric elements by a low power source voltage by forming the elements of a laminate of a plurality of layers. CONSTITUTION:First and second thin piezoelectric elements 15, 17 are so treated that polarizing directions (+, -) become vertically the same. A first terminal of a SIN wave power source 13 is connected to a stator 2 as a common electrode and a second common electrode 18, a second terminal of a COS wave power source 14 is connected to the SIN side electrode 16A. The first terminal of the power source 14 is connected to the stator 2 as the common electrode and the second common electrode 18, and the second terminal of the source 14 is connected to a COS side electrode 16B. Thus, a traveling vibration wave can be generated at the protrusion 2E of the stator 2. In this case, since the elements 15, 17 are thin, its drive power source can be lowered at its voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor which can be driven at a low voltage.

[0002]

2. Description of the Related Art FIG. 3 is a schematic sectional view showing a conventional ultrasonic motor. In the figure, 1 is a conductive support member, and this support member 1 is provided with a central hole 1A, a cover screw hole 1B, a stator screw hole 1C, and a mounting hole 1D. Reference numeral 2 is a stator, and this stator 2 is formed in a disk shape, and is provided with a center hole 2A and a mounting hole 2B. Further, on the upper surface side of the peripheral portion 2C of the stator 2, a large number of thin grooves 2D are cut as shown in FIG.
The protrusion 2E is formed, and the piezoelectric body 3 is adhesively fixed to the lower surface side of the peripheral edge portion 2C. The piezoelectric body 3 is processed so that the directions of polarization (indicated by + and −) are different from each other as shown in FIG. 4A, 4B, and 4C are SIs bonded and fixed to the lower surface side of the piezoelectric body 3.
An N-side electrode, a COS-side electrode, and a detection electrode.

Reference numeral 5 denotes a rotor, and this rotor 5
Is formed in a disk shape and is provided with a center hole 5A. The lower surface side of the peripheral edge portion 5B of the rotor 5 is formed in a convex shape and is pressed against the upper surface side of the peripheral edge portion 2C of the stator 2. 6 is a disc spring, and the disc spring 6
Is provided with, for example, an octagonal through hole 6A.

Reference numeral 7 is a friction member.
Is attached to the upper surface of the rotor 5, and the disc spring 6 is in pressure contact therewith. Reference numeral 8 is a thrust bearing, 9 is a cover, and this cover 9 has a recess 9A having a central hole,
And a mounting hole 9B.

Reference numeral 10 denotes an output shaft. One end of the output shaft 10 is supported by the thrust type bearing 8 and a portion of the disc spring 6 that comes into contact with the octagonal through hole 6A has a diameter of 8.
It is formed in a rectangular shape. The output shaft 10 includes a through hole 6A for the disc spring 6, a through hole (not shown) for the friction member 7,
It is exposed to the outside through the center hole 5A of the rotor 5, the center hole 2A of the stator 2, and the center hole 1A of the support member 1.

Reference numeral 11 denotes a screw, which is fixed to the stator screw hole 1C of the support member 1 through the mounting hole 2B of the stator 2 to fix the stator 2. Reference numeral 12 denotes a screw, and the screw 12 is screwed into the cover screw hole 1B of the support member 1 through the mounting hole 9B of the cover 9 to fix the cover 9 to the support member 1.

Then, as shown in FIG. 4, a SIN wave power source 13 is connected between the stator 2 as a common electrode and the SIN side electrode 4A, and a COS is provided between the stator 2 as a common electrode and the COS side electrode 4B. By connecting the wave power source 14, a progressive vibration wave can be generated in the protrusion 2E of the stator 2.

[0008]

However, in the conventional ultrasonic motor, since the piezoelectric body has a large thickness and the member constituted by the piezoelectric body and the stator resonates, a high frequency signal is generated. There was a problem that the power supply voltage had to be increased.

[0009]

SUMMARY OF THE INVENTION An ultrasonic motor according to the present invention comprises a stator, a piezoelectric body which is adhesively fixed to a lower side of a peripheral portion of the stator and generates a progressive vibration wave, and an upper side of a peripheral portion of the stator. In the ultrasonic motor including a rotor that is pressed into contact with the rotor and is rotated by a progressive vibration wave generated by being amplified above the peripheral portion of the stator, and an output means for extracting the drive rotation of the rotor to the outside, The body is configured as a laminated body of a plurality of layers.

[0010]

According to the present invention, each piezoelectric body can be driven with a low power supply voltage by forming the piezoelectric body as a laminated body of a plurality of layers.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partially detailed sectional side view showing an embodiment of an ultrasonic motor according to the present invention. In the figure, 1
Reference numeral 5 is a first thin piezoelectric body, and this first thin piezoelectric body 15
Has its upper surface side bonded and fixed to the lower surface side of the stator 2. 16A, 16B, and 16C are first SIN-side electrodes that are adhesively fixed to the lower surface side of the first thin piezoelectric body 15,
The first COS side electrode and the first detection electrode.

Reference numeral 17 denotes a second thin piezoelectric body, and the second thin piezoelectric body 17 has an upper surface side which is the first SIN side electrode 16
A, first COS side electrode 16B, and first detection electrode 1
Adhesively fixed to the lower surface side of 6C. Reference numeral 18 denotes a second common electrode, and the upper surface side of the second common electrode 18 is adhesively fixed to the lower surface side of the second thin piezoelectric body 17.

The first thin piezoelectric body 15 and the second thin piezoelectric body 17 are processed so that the polarization directions (indicated by + and-) in the vertical relationship are the same.
Then, one terminal of the SIN wave power supply 13 is connected to the stator 2 as a common electrode and the second common electrode 18,
The other terminal of the N-wave power supply 13 is connected to the SIN side electrode 16A. Further, one terminal of the COS wave power source 14 is connected to the stator 2 as the common electrode and the second common electrode 18, and the other terminal of the COS wave power source 14 is connected to the COS side electrode 1.
By connecting to 6B, a progressive vibration wave can be generated in the protrusion 2E of the stator 2.

In this case, since the first thin piezoelectric body 15 and the second thin piezoelectric body 17 are thin, it is possible to lower the driving power supply voltage. Since the first thin piezoelectric body 15 and the second thin piezoelectric body 17 are distorted in the same direction, they can be distorted in the same manner as if the whole is made of a single piezoelectric body.

FIG. 2 is a partially detailed sectional side view showing another embodiment of the ultrasonic motor according to the present invention. In the figure, a first thin piezoelectric body 15 and a second thin piezoelectric body 17
Are processed so that the polarization directions (indicated by + and −) in the vertical relationship are different. Reference numeral 19 denotes an insulating plate, and the insulating plate 19 includes the SIN side electrode 16A and the COS side electrode 1
6B, provided between the detection electrode 16C and the second common electrode 18. The second common electrode 18 is the second thin piezoelectric body 17
Function as a common electrode of the. 20A, 20B, and 2
Reference numeral 0C denotes a second SIN side electrode, a second COS side electrode, and a second detection electrode provided on the lower surface side of the second thin piezoelectric body 17.

In the ultrasonic motor having this structure, one terminal of the SIN wave power source 13 is connected to the stator 2 as the common electrode and the second common electrode 18, and the other terminal of the SIN wave power source 13 is on the SIN side. It is connected to the electrode 16A and the second SIN side electrode 20A. Further, one terminal of the COS wave power source 14 is connected to the stator 2 as the common electrode and the second common electrode 1
8 and the other terminal of the COS wave power source 14 is COS
By connecting to the side electrode 16B and the second COS side electrode 20B, a progressive vibration wave can be generated in the protrusion 2E of the stator 2.

In this case, since the first thin piezoelectric body 15 and the second thin piezoelectric body 17 are thin, it is possible to lower the driving power supply voltage. Since the first thin piezoelectric body 15 and the second thin piezoelectric body 17 are distorted in the same direction, they can be distorted in the same manner as if they are entirely composed of a single piezoelectric body.

In the above embodiments, two piezoelectric laminates are used, but the present invention is not limited to this, and three or more piezoelectric laminates can be used in the same manner.

[0019]

As described above in detail, according to the ultrasonic motor of the present invention, each piezoelectric body is driven by a low power supply voltage by forming the piezoelectric body as a laminated body of a plurality of layers. Therefore, the ultrasonic motor can be driven at a low voltage.

[Brief description of drawings]

FIG. 1 is a partially detailed sectional side view showing an embodiment of an ultrasonic motor according to the present invention.

FIG. 2 is a partially detailed cross-sectional side view showing another embodiment of the ultrasonic motor according to the present invention.

FIG. 3 is a schematic sectional view showing a conventional ultrasonic motor.

4 is a partially detailed cross-sectional side view of FIG.

[Explanation of symbols]

 15 First Thin Piezoelectric Body 16A SIN Side Electrode 16B COS Side Electrode 16C Detection Electrode 17 Second Thin Piezoelectric Body 18 Second Common Electrode 19 Insulating Plate 20A Second SIN Side Electrode 20B Second COS Side Electrode 20C Second Detection electrode

Claims (1)

[Claims] 1. A stator, a piezoelectric body which is fixedly adhered to a lower side of a peripheral portion of the stator and generates a progressive vibration wave, and a pressure contact is made to an upper side of the peripheral portion of the stator and is amplified to an upper side of the peripheral portion of the stator. In an ultrasonic motor including a rotor that is rotated by a progressive vibration wave generated as a result and an output unit that takes out the driving rotation of the rotor to the outside, the piezoelectric body is configured as a laminated body of a plurality of layers. Characteristic ultrasonic motor.