JPH05284761A - Manufacture of stator of ultrasonic motor - Google Patents

Abstract

PURPOSE:To improve quality of a stator of an ultrasonic motor and to obtain a method for manufacturing to improve yield. CONSTITUTION:An integral electrode pattern 13 is formed on a piezoelectric element material 11. A vibrator material 12 is adhered to the material 11 formed with the pattern. Central holes are opened at the element material and the vibrator material after adhering. Then, a shape of the element is processed in step 16. Further, dividing electrodes are formed at the element in step 17, and the element is polarized in step 18. Then, a shape of the vibrator is formed in step 19. A stator of an ultrasonic motor is completed by the above steps.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a stator of an ultrasonic motor in which a moving body is frictionally driven by ultrasonic vibration utilizing expansion and contraction movement of a piezoelectric element.

[0002]

2. Description of the Related Art FIG. 16 is a sectional view of a conventional ultrasonic motor. In the figure, a piezoelectric element 161 is bonded to the lower surface of the vibrating body 162. A voltage having a frequency in the ultrasonic band is applied to the piezoelectric element 161 to expand / contract the piezoelectric element 161. The vibrating body 162 to which the piezoelectric element 161 is bonded is flexed and vibrated, and the comb teeth 163 amplify the flexural vibration.
The rotor 165 is rotated by the frictional force between the rotor 165 and the upper surfaces of the tips of the comb teeth 163 which are in contact with each other. There are "traveling wave method" and "standing wave method" as typical driving methods of ultrasonic motors.
The electrode structure of the piezoelectric element is different.

FIG. 17 is a plan view of an electrode structure on the first surface of a conventional piezoelectric element. Here, FIG. 17 shows an integrated electrode formation surface. FIG. 18 is a plan view of an electrode structure on the second surface of a conventional piezoelectric element. Here, FIG. 18 shows a split electrode formation surface. 17 and 18 show an integrated electrode forming surface and a split forming surface of a piezoelectric element to which a vibrating body used in a conventional stator is adhered. The electrode structure of the piezoelectric element shown in these figures is a "traveling wave type". It is an example of the electrode structure used.

FIG. 15 is an explanatory view showing a conventional process for processing a piezoelectric element material. A stator 16 as shown in FIG.
In order to realize No. 4, the cylindrical block of the piezoelectric element material shown in FIG. Next, as shown in FIG. 15B, a central hole 151 is formed in the center of the cylindrical block 150 of the piezoelectric element material by a mechanical method. Then, the cylindrical block 150 having the central hole 151 is formed as shown in FIG.
As shown in (c), the vibrator material 152 in a chip shape is cut. Further, the disk-shaped piezoelectric element 171 shown in FIG. 17 is formed by lapping to a predetermined thickness with a lapping machine.

The first surface of the piezoelectric element 171 is shown in FIG.
The electrode 173 as shown in FIG. In addition, the piezoelectric element 1
On the second surface of 71, split electrodes 183, 1 as shown in FIG.
84 is formed. Further, in the figure of FIG. 18, (+),
A method of manufacturing a stator has been employed in which the polarization treatment as shown in (-) is applied and the surface on which the integrated electrode is formed is bonded to the vibrating body 162.

[0006]

In the method of manufacturing a stator as described above, a piezoelectric element having a disc shape is produced by cutting and lapping the piezoelectric element from a cylindrical block. There is a problem that cracks are generated in the piezoelectric element in the lapping process and the manufacturing yield is low. Further, there is a problem that cracks occur in the piezoelectric element in the electrode forming step, the polarization treatment step, and the step of bonding the vibrating body and the piezoelectric element.

Therefore, an object of the present invention is to solve the above problems and to obtain a manufacturing method which improves the quality of the stator and improves the yield.

[0008]

In order to solve the above-mentioned problems, the present invention is to form an integrated electrode on one surface of a piezoelectric element raw material and adhere it to a vibrating body, and after adhering the piezoelectric element raw material to the vibrating body, The piezoelectric element raw material is lapped, and then divided electrodes are formed on the surface opposite to the bonding surface of the piezoelectric element and positive (+) and negative (-) polarization is applied to form a stator of an ultrasonic motor.

[0009]

With the above manufacturing method, the piezoelectric element can be prevented from cracking during bonding. Furthermore, since the piezoelectric element material is adhered to the vibrating element material, it is reinforced by the vibrating element material, so cracking during lapping is prevented, and electrode formation and polarization treatment are performed on the surface opposite to the piezoelectric element adhering surface. Even in the step of performing the step, it is possible to prevent the piezoelectric element from cracking, which is very advantageous for improving the productivity and increasing the efficiency in making the ultrasonic motor small, small in diameter, and thin.

[0010]

Embodiments (1) First Embodiment An embodiment of the present invention will be described below with reference to the drawings. Figure 1
[Fig. 4] is a process drawing showing a first embodiment of the stator manufacturing method of the present invention. An integrated electrode pattern is formed on the piezoelectric element material 11 (step 13). The vibrating element raw material 12 is bonded to the piezoelectric element raw material on which the integrated electrode pattern is formed (step 1).
4). A central hole is opened in the piezoelectric element raw material and the vibrating raw material after the bonding (step 15).

The shape of the piezoelectric element is processed (step 16).
Split electrodes are formed on the piezoelectric element (step 17). The piezoelectric element is polarized (step 18). The shape of the vibrator is processed (step 19). Through the above steps, the stator 1 of the ultrasonic motor
10 is completed. FIG. 2 is a perspective view of a piezoelectric element raw material applied to the first embodiment of the present invention. First, the piezoelectric element raw material 21
To form. T1 indicates the thickness of the piezoelectric element raw material 21. As shown in FIG. 16, the thickness of the completed piezoelectric element is T0.
Then, T1 is thicker than T0.

FIG. 3 is a perspective view of a vibrating element raw material applied to the first embodiment of the present invention. In FIG. 3, U1 indicates the thickness of the vibrating element raw material 31. When the vibrating body is completed, assuming that the thickness of U0 shown in FIG. 16 is, U1 is equal to U0 or U
Set to a value greater than 0. The material of the vibrator material is one of the design parameters of the ultrasonic motor, and is generally SUS.
Material, copper alloy, aluminum alloy, etc. are used. Although an aluminum alloy is used in this embodiment, other materials may be used.

FIG. 4 is a perspective view of a piezoelectric element raw material having an integrated electrode pattern applied to the first embodiment of the present invention. An integrated electrode pattern 42 is formed on one surface of the piezoelectric element raw material 21. FIG. 5 is a perspective view showing a state in which the vibrating element raw material and the piezoelectric element raw material applied to the first embodiment of the present invention are bonded.

The piezoelectric element material 21 on which the vibrating element material 31 and the integrated electrode pattern 42 are formed is bonded with the adhesive 51. At this time, the adhesive is used to reduce the adhesive layer as much as possible.
Use a non-conductive epoxy adhesive. 17 and 18
In the electrode structure of the piezoelectric element shown in (1), the vibrating body itself has a GND potential which is an intermediate value between the potential electrically applied to the first surface and the potential electrically applied to the second surface. The vibrating body and the integrated electrode pattern need to be electrically connected. Therefore, when the vibrating body material 31 and the electrode pattern 42 of the piezoelectric element material 21 are bonded, a high pressure is applied. And the adhesive 5
1 is made as thin as possible so that the vibrating body material 21 and the integrated electrode pattern 42 are electrically connected. When the adhesive is a conductive adhesive, the adhesive layer becomes thick due to the conductive material contained in the conductive adhesive, and the vibration is absorbed by the adhesive layer.

FIG. 6 is a cross-sectional view showing a state in which a vibrator material and a piezoelectric element material to which the first embodiment of the present invention is applied are punched. A center hole 64 and a center hole 63 are formed in the vibrating body 31 to which the piezoelectric element 21 is bonded. As a method of drilling,
Any of a mechanical method using a stepped drill, an ultrasonic vibration machining method, laser drilling, or the like is possible. At this time, since the piezoelectric element raw material is fragile, if the punching is performed from the side of the piezoelectric element raw material so that the piezoelectric element raw material 62 is released, the piezoelectric element raw material 61 can be completely prevented from cracking.

FIG. 7 is an explanatory view of the processing steps of the piezoelectric element applied to the first embodiment of the present invention. The piezoelectric element 21 is processed from the thickness T1 to the final thickness T0 by lapping or the like. The lower surface 73 of the piezoelectric element 71 processed up to the above steps
Then, polarization is performed by forming the divided electrodes shown in FIG.

FIG. 8 is an explanatory view of a vibrating body shape processing step applied to the first embodiment of the present invention. As shown in FIG. 8, the comb teeth 83 are processed in the vibrator raw material 31 having a thickness of U1 to form a vibrator 82 having a thickness of U0. The stator 84 is completed through the above-described shape processing steps.

In the first embodiment of the present invention, the comb teeth may be formed in advance on the vibrating material 31. In this case, the subsequent process relating to the processing of the vibrating body material is unnecessary. (2) Second Embodiment FIG. 9 is a perspective view of a piezoelectric element sheet material to which the second embodiment of the present invention is applied.

FIG. 10 is a perspective view of a vibrator material to which the second embodiment of the present invention is applied. In FIG. 9, the piezoelectric element sheet material 91 has a size such that two or more piezoelectric elements can be obtained as a finished product. The integrated electrode pattern 92 is formed on one surface of the piezoelectric element sheet material 91. The vibrating element raw material 101 has substantially the same size as the piezoelectric element sheet material 91.

FIG. 11 is a sectional view showing a state in which a piezoelectric element sheet material and a vibrating element raw material to which the second embodiment of the present invention is applied are bonded. The piezoelectric element sheet material 91 on which the electrode pattern 92 is formed and the vibrating element raw material 101 are adhered with an adhesive 112. FIG. 12 is a cross-sectional view showing a state in which holes are made in the vibrator material and the piezoelectric element sheet material to which the second embodiment of the present invention is applied.

Piezoelectric element sheet material 91 and vibrator material 101
The central holes F1, G1, F2, G2, F3, G3, etc. are opened. FIG. 13 is an explanatory diagram of a piezoelectric element processing step to which the second embodiment of the present invention is applied. The piezoelectric element 91 is changed from the thickness T2 to the final thickness T of the piezoelectric element 131 by lapping or the like.
Process to 0.

The piezoelectric element lower surface 13 processed through the above steps
In FIG. 3, the divided electrode patterns shown in FIG. Then, by laser processing,
The individual pieces in the state shown in FIG. 7 are cut off. Then, the stator 84 is completed through the vibrator shape processing step 19 shown in FIG. (3) Third Embodiment FIG. 14 is an explanatory diagram of a vibrating body block processing step to which the third embodiment of the present invention is applied.

Comb teeth 144 are attached to the vibrating material 142 in N / C.
The vibrator block 143 is formed by processing with a machine or the like.
The vibrating body block 143 is cut into individual pieces by laser processing or the like. The third embodiment further reduces man-hours.

[0024]

As described above, according to the present invention, the piezoelectric element raw material is lapped to a predetermined thickness through the bonding step of adhering the piezoelectric element raw material to the vibrating body raw material, and the piezoelectric element raw material is bonded to the vibrating body raw material at a predetermined thickness. It is possible to prevent cracking and cracking during lapping. When using a piezoelectric element sheet material, if it is processed to a predetermined thickness before bonding, the yield will deteriorate due to cracking during lapping, cracking during handling, and cracking during bonding, whereas bonding before lapping By doing so, the yield is much improved. Further, in the polarization step, a large number of pieces can be simultaneously polarized, which has the effect of increasing manufacturing efficiency.

[Brief description of drawings]

FIG. 1 is a process drawing showing a first embodiment of a stator machining process of the present invention.

FIG. 2 is a perspective view of a piezoelectric element raw material applied to the first embodiment of the present invention.

FIG. 3 is a perspective view of a vibrating element raw material applied to the first embodiment of the present invention.

FIG. 4 is a perspective view of a piezoelectric element raw material having an integrated electrode pattern applied to the first embodiment of the present invention.

FIG. 5 is a perspective view showing a state in which a vibrating element raw material and a piezoelectric element raw material applied to the first embodiment of the present invention are bonded.

FIG. 6 is a cross-sectional view showing a state in which a vibrator material and a piezoelectric element material applied to the first embodiment of the present invention are perforated.

FIG. 7 is an explanatory diagram of a piezoelectric element processing step applied to the first embodiment of the present invention.

FIG. 8 is an explanatory view of a vibrating body shape processing step applied to the first embodiment of the present invention.

FIG. 9 is a perspective view of a piezoelectric element sheet material to which a second embodiment of the present invention is applied.

FIG. 10 is a perspective view of a vibrator material to which the second embodiment of the present invention is applied.

FIG. 11 is a cross-sectional view showing a state in which a piezoelectric element sheet material and a vibrating element raw material to which the second embodiment of the present invention is applied are bonded.

FIG. 12 is a cross-sectional view showing a state in which a vibrator material and a piezoelectric element sheet material to which a second embodiment of the present invention is applied are perforated.

FIG. 13 is an explanatory diagram of a piezoelectric element processing step to which the second embodiment of the present invention is applied.

FIG. 14 is an explanatory diagram of a vibrating body block processing step to which the third embodiment of the present invention is applied.

FIG. 15 is an explanatory diagram showing a conventional process for processing a piezoelectric element material.

FIG. 16 is a sectional view of a conventional ultrasonic motor.

FIG. 17 is a plan view of an electrode structure on the first surface of a conventional piezoelectric element.

FIG. 18 is a plan view of an electrode structure on a second surface of a conventional piezoelectric element.

[Explanation of symbols]

 11 Piezoelectric element raw material 12 Vibrating body raw material 13 Integrated electrode pattern forming step 14 Bonding step 15 Center hole processing step 16 Piezoelectric element shape processing step 17 Piezoelectric element divided electrode forming step 18 Polarizing step 19 Vibrating body shape processing step 110 Stator completed

Claims (1)

[Claims] 1. An ultrasonic wave, comprising: a stator having a piezoelectric element bonded to a lower surface of a vibrating body; and a rotor which is pressed against the other surface of the vibrating body and frictionally driven by flexural vibration of the vibrating body due to expansion and contraction of the piezoelectric element. A method of manufacturing a stator of a motor, comprising: a step of bonding a piezoelectric element to a vibrating body; and a step of processing the piezoelectric element and the vibrating body into a predetermined shape. Method.