JPH01129781A - Ultrasonic motor device - Google Patents

Abstract

PURPOSE:To provide a stable frictional resistance by forming friction means made of fluororesin containing carbon fiber, powder on one face between a vibrator and a moving body. CONSTITUTION:An ultrasonic motor has a platelike piezoelectric unit 11, a vibrator 12 made of a platelike solid material adhered and secured with the unit 11, and a moving body 13 made of a solid material similar to the vibrator. A frictional material layer 14 made of fluororesin containing carbon fiber or carbon powder formed on the operating face of the body 13 in pressure contact with the vibrator 12. Thus, a high frequency electric field of ultrasonic frequency is applied to the unit 11, thereby generating a traveling wave of an ultrasonic vibration at the unit 11 and the vibrator 12. In this case, the layer 14 is driven by the frictional force to the vibrator 12. When power from a power source is not input, frictional force corresponding to the product of the pressure and the frictional coefficient therebetween is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ultrasonic motor device that utilizes mechanical vibration waves generated by electrical energy of a piezoelectric element, etc. BACKGROUND OF THE INVENTION A conventional ultrasonic motor device will be described below. . Fourth
The figure is a side sectional view of the main parts of a conventional ultrasonic motor device, in which 1 is a piezoelectric body composed of a plurality of piezoelectric elements having an ultrasonic natural frequency, and 2 is a piezoelectric body in which the piezoelectric body 1 is fixed with adhesive. 1 is a vibrating body that vibrates together with the vibrating body 2; 3 is a movable body that moves when the vibrating body 2 is photographed; and 4 is a friction material layer that is fixed to the movable body 3 and is brought into pressure contact with the vibrating body 2.

The operation of the ultrasonic motor device configured as described above will be described below.

First, when an electrical input based on the ultrasonic natural frequency is applied to the piezoelectric body 1, ultrasonic vibrations are generated in the thickness direction.

This ultrasonic vibration causes each point within the vibrating body 2 to move in an ellipse as shown in B based on the composite physical structure and characteristics of the piezoelectric body 1 and the vibrating body 2. And this elliptical motion B
If it is counterclockwise in FIG. 4, a transverse wave-like traveling wave is generated in the right direction in the figure, that is, in the incoming direction. At this time, as is clear if we consider the phase of the elliptical motion of each part,
The point at the head of the traveling wave inside the vibrating body 2 moves in the opposite direction to the traveling wave, while the point at the trough of the traveling wave moves in the direction of the traveling wave.
The moving body 3, which is in contact with the head of the traveling wave via the friction material layer 4, moves to the left in the figure, that is, in the C direction, in accordance with the movement of the wave head in the opposite direction.

In such ultrasonic motor devices, metals such as iron, stainless steel, or aluminum are conventionally used as the vibrating body, and the metal surface of such a vibrating body is in contact with a friction material fixed to a moving body. It becomes. Furthermore, it has been proposed to use a plastic material as the friction material.

Problems to be Solved by the Invention However, in the conventional configuration described above, since the friction means fixed to the surface of the movable body 3 and the vibrating body 2 come into contact with each other, as the drive time of the motor passes for a long time, the friction means and the vibration Since abrasion powder is generated from the body 2 and the frictional resistance between the movable body 3 and the vibrating body 2 changes, there has been a problem in that the holding torque of the motor changes over time.

The present invention solves the above-mentioned conventional problems, and aims to provide an ultrasonic motor device that can reduce the amount of abrasion powder generated on the contact surface between the friction means and the vibrating body and obtain stable frictional resistance. purpose.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention uses a friction means made of a fluororesin containing at least carbon fiber or carbon powder on at least one of the mutually facing surfaces of the vibrating body and the movable body. It has a configuration that is formed in the following manner.

Function: With the above-described structure, the present invention can reduce the amount of abrasion powder generated from the friction means and the vibrating body, and can provide stable frictional resistance for a long period of time.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of essential parts of an ultrasonic motor device according to an embodiment of the present invention. In FIG. 1, 11 is a plate-shaped piezoelectric body, 12 is a vibrating body made of a solid plate to which the plate-shaped piezoelectric body 11 is glued and fixed, 13 is a moving body made of a solid material similar to the vibrating body 12, and 14 is a vibrating body. This is a friction material layer made of a fluororesin containing at least carbon fiber or carbon powder, which is in pressurized contact with the body 12 and formed on the operating surface of the movable body 13.

The operation of the ultrasonic motor device of this embodiment configured as described above will be explained below. First, the plate-shaped piezoelectric body 11
By applying a high-frequency electric field having an ultrasonic frequency to the piezoelectric plate 11 and the vibrator 12, a traveling wave of ultrasonic vibration is generated as described above. At this time, the friction material layer 14 formed on the movable body 13 that is in contact with the vibrating body 12 at the head of the traveling wave is driven by the frictional force between the vibrating body 12 and the movable body 13 . When power is not input, the vibrating body 12
A friction force corresponding to the product of the pressurizing force and the friction coefficient is generated between and the friction material layer 14, and if the power is cut off during driving, this friction force will act as a holding force r.

Here, the friction material layer 14 is made of a friction material made of a fluororesin containing at least carbon fiber or carbon powder.

This carbon fiber is not particularly limited, and forms such as short fibers, long fibers, continuous fibers, woven fabrics, felt, and paper can be used. Furthermore, carbon powder is not particularly limited, and can be used in the form of graphite, carbon, or the like. Further, as the fluororesin, those in the form of tetrafluoroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, trifluorochloroethylene resin, resin, and purple olohair alkoxy resin can be used.

A more specific example will now be described.

FIG. 2 shows a specific example of the diameter 60mm. .

It is a perspective view of a disc type ultrasonic motor with a thickness of 81III,
111LFi disk piezoelectric body, 121L disk piezoelectric body 111
A large number of protrusion segments 151 are adhesively fixed to the surface of L.
It is a stainless steel vibrating body having a circumferential arrangement of L. This protrusion segment) 15& is provided to facilitate mechanical imaging of the vibrating body portion and to increase the amplitude. 131L is stainless steel moving body, 14IL is stainless steel moving body 1
A friction material layer having a thickness of 05 to 3 m and made of fluororesin containing carbon fiber or carbon powder is adhesively fixed to 3&. Although the vibrating body 12a and the movable body 131L are not shown, the appropriate springs and screws are pressed against each other by a means, and the surface of the protrusion segment 1151L and the friction material layer 14
A and A are shown close up.

The friction material layer 141L was manufactured as shown below! friction material was used.

(1) Manufacturing method of 1 friction material: Carbon fiber woven fabric (Pespite W11o3 [trade name] manufactured by Toho Rayon Co., Ltd.).

Plain weave, fabric weight 12 es g/i) was impregnated with an aqueous suspension of tetrafluoroethylene resin (Polyflon TFE Dispersion D-1 [trade name] manufactured by Daikin Industries, Ltd.), and after drying 1
A molded sheet made of 66% carbon fiber and 36% tetrafluoroethylene resin, which was laminated with 0 sheets and fired at a temperature of 370'C under a pressure of aookg/d, was made into a sheet with a thickness of O, S. A friction material was obtained by polishing.

(2) Manufacturing method of I friction material B: Carbon fiber felt (
Nippon Carbon Co., Ltd. Carporon Felt 3 people [Product name],
5 mm thick) was impregnated with an aqueous suspension of tetrafluoroethylene resin (Polyflon D1 [trade name] manufactured by Daikin Industries, Ltd.), dried, and then baked at a temperature of 370°C under a pressure of aookg/d. Friction material B was obtained by polishing a molded sheet made of 66 cm of carbon fiber and 46 cm of tetrafluoroethylene to a thickness of 111 II.

(3) Manufacturing method of I friction material C: Carbon fiber chop (
Carbon NF-C4 (product name) manufactured by Nippon Carbon Co., Ltd.

411℃ long) and polytetrafluoroethylene resin powder (Polyflon Powder M-15 (trade name) manufactured by Daikin Industries, Ltd.) were mixed uniformly in a mixer and put into a mold to produce 400 kg/do.
Carbon fiber 25 obtained by firing at a temperature of 370'C under pressure
Friction material C was obtained by polishing a molded sheet made of 76% and tetrafluoroethylene resin to a thickness of 111111%.

(4) Manufacturing method for friction material Nige □ Graphite powder (carbon powder manufactured by Tokai Carbon Co., Ltd., average particle size of 1 μm or less) and tetra7ethylene ethylene resin powder (Polyflon M-1 manufactured by Daikin Industries, Ltd.)
Graphite powder 36qA and tetrafluoroethylene resin obtained by uniformly mixing 5 (trade name) with a mixer, charging it into a mold, and firing at a temperature of 370"C under a pressure of 4ook/d. A molded sheet consisting of 66 inches was polished to a thickness of 2 inches to obtain a friction material Dt-.

(5) i! Manufacturing method of rubbing material
Aqueous suspension of tetrafluoroethylene resin (Polyflon Dispersion D manufactured by Daikin Industries, Ltd.)
-1 [Product Name]), dried, rolled concentrically and laminated, and placed in an autoclave at 1o kg/cl at 380°C.
A cylindrical molded body made of 66 pieces of carbon fiber and 3 s% of tetrafluoroethylene resin obtained by firing at a temperature of 'C was cut into slices to obtain a friction material X having a thickness of 3M.

An ultrasonic motor using the friction material layer 14& made of each of the friction materials M to K obtained as described above is constructed, and the electrodes are arranged so that four traveling waves are excited in the circumferential direction of the disk. and a resonant frequency of 70 Kl.

A voltage SOV input was applied to drive the motor.

Regarding the ultrasonic motor using the wear material layer 141L made of each of the friction materials mentioned above, after driving for a predetermined time, whether or not to restart when the power is intermittent input, the holding torque after the power is cut off, the vibration body surface Table 1 shows the results of measuring the presence or absence of scratches and wear, the depth of wear of the friction material, and the presence or absence of noise during driving.

(6) For comparison, a friction material F made of polytetrafluoroethylene resin (a fluororesin obtained by pressurized firing of Polyflon M-15 [trade name] manufactured by Daikin Industries, Ltd.) was polished to a thickness of 1 layer. Table 1 also shows the measurement results for the ultrasonic motor using the friction material layer 141L.

(The following is a blank space) As is clear from Table 1, with respect to the ultrasonic motors using the friction materials A to N, the change in holding torque over time is small, and there is no problem with respect to restartability. Furthermore, a highly reliable ultrasonic motor is obtained in which no noise is observed, and there is little wear of the electric film material layer 14a made of a friction material after 24 hours of operation, and little damage and wear of the vibrating body 12&, which is the contact partner. be able to.

On the other hand, when the friction material F made of only fluororesin was used and the screw tightening force was set so that the initial holding torque was 1500 g'ff, the motor did not drive. Therefore, the initial holding torque is 300gec.
Although the screws were tightened with less force so as to reach m, the restartability after 24 hours was unstable, and noise was observed during driving. Furthermore, after 24 hours, there was a lot of wear on the friction material, and the wear depth was 7 μm. Note that when the holding torque is small, there is a drawback that the upper limit of the starting torque of the motor is also small.

Next, as the friction material layer 1jLL, a disc-type ultrasonic motor was constructed in the same manner as in the specific example described above, using the friction material G-1 manufactured as follows.

(7) Manufacturing method of friction material G: #Fiber felt (Carporon Felt manufactured by Nippon Carbon Co., Ltd. [Product name] Thickness 5 sm)
An aqueous suspension of trifluorochloroethylene resin (Guiflon CTFK Dispersion D-ss manufactured by Daikin Industries, Ltd.)
After impregnating with product name) and drying, 300 kg/d
85% carbon fiber by firing at 310℃ under O pressure
Friction material G was obtained by polishing a sheet-like molded product consisting of 4 s% trifluorochlorinated ethylene resin to a thickness of 111II.

(8) Manufacturing method of friction material H: Carbon fiber woven fabric (Toho Rayon Pesphite W1103 [trade name], plain weave, fabric weight 1
(25 g/d) was impregnated with an aqueous suspension of tetrafluoroethylene-hexafluoropropylene copolymer resin (Neoflon FIEP Disversion ND-1 (trade name) manufactured by Daikin Industries, Ltd.), and after drying, 10 sheets were laminated. It was fired at a temperature of 370"C under a pressure of 300 kg/gl to form 66 pieces of carbon fiber and 3 pieces of tetrafluoroethylene-hexafluoropropylene copolymer resin.
Friction material H was obtained by polishing a sheet-like molded product with a thickness of 6%.

(9) Manufacturing method of friction material I: 26% graphite powder (carbon powder manufactured by Tokai Carbon Co., Ltd., apparent particle size of 1 μm or less) and silicon carbide whisker powder (SCW manufactured by Tateho Chemical Industry Co., Ltd.)
1-so (product name), fiber diameter 0.05-1.6μm1
length 20-200 μm) 16% and tetrafluoroethylene resin powder (Polyflon M-15 (trade name) manufactured by Daikin Industries, Ltd.)
) were uniformly mixed in a mixer and fired at a temperature of 370''C under a pressure of 4ookg/d in Venus, and a sheet-like molded product was polished to a thickness of 211IIK to obtain Friction Material I.

Using the friction material layer 141L made of friction material G, After driving, whether or not there is a restart when power is applied intermittently, the holding torque after the power is cut off, whether there is damage or wear on the surface of the vibrating body,
Table 2 shows the results of measuring the depth of wear of the friction material and the presence or absence of noise during driving.

(The following is a blank space) Table 2 As is clear from Table 2, for the ultrasonic motors using any of G, H, and I friction materials, the change in holding torque over time was small, and there were no problems with restartability. Furthermore, the ultrasonic motor is highly reliable, with no noise generation observed, and less wear on the friction material layer 141L made of friction material after 24 hours of operation, and less damage and wear on the vibrating body 121L, which is the contact partner. Obtainable.

In addition, although the disc-type ultrasonic motor has been comparatively examined above, the piezoelectric body 11b and the protruding segment 15b'i (J vibrating body 12°b and the friction material layer 14b) as shown in FIG.
The same applies to an annular ultrasonic motor consisting of a moving body 13b forming a T-shape. That is, in the ultrasonic motor having such a shape, the thickness of the friction material layer 14b is set to Q6~2.
1111, similar results can be obtained by using the aforementioned friction materials M~X, aXt-.

As described above, according to this embodiment, by forming the operating surface of the friction material layer 14 with the movable body 13 from at least carbon fiber or fluororesin containing carbon powder, wear of the vibrating body 12 is eliminated, and The source of wear on the friction material layer 14 can be minimized, and as a result, the change in holding torque over time is reduced, excellent restartability can be obtained, and noise generation can be prevented.

In this example, in addition to the carbon woven fabric or carbon powder, it is also possible to add fillers such as other fibers and powder to the fluororesin.

Effects of the Invention As is clear from the above embodiments, according to the present invention, the friction means made of a fluororesin containing at least carbon fiber or carbon powder is applied to the surfaces of the vibrating body and the movable body facing each other in an ultrasonic motor device. By forming it on at least one side, the amount of abrasion powder generated on the operating surfaces of the moving body and the vibrating body is reduced, and stable frictional resistance can be obtained, so that changes in the motor's holding torque over time can be reduced. Furthermore, it is possible to realize an excellent ultrasonic motor device that has stable starting performance and does not generate noise during driving.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of essential parts of an ultrasonic motor device according to an embodiment of the present invention, and FIG. 2 is a perspective view of a disk-type ultrasonic motor device according to a specific embodiment of the present invention. 3 is a perspective view of an annular ultrasonic motor device in another specific embodiment, and FIG. 4 is a side sectional view of the main parts of a conventional ultrasonic motor device.・・・-Piezoelectric body, 2゜1
2, 121L, 12b--vibrating body, 3, 13
゜131L, 13b...Moving object, 4, 14
, 141LX. 14b...Friction material layer. Name of agent: Patent attorney Toshio Nakao and 1 other person11
- Pressure 11a~...Piezoelectric body 4 -Mine material

Claims (3)

[Claims] (1) A vibrating body that generates vibration waves by vibration of a piezoelectric body, a movable body that is brought into pressure contact with the surface of this vibrating body and moves by the vibration waves of the vibrating body, and a combination of the vibrating body and the movable body. 1. An ultrasonic motor device comprising friction means formed on at least one of opposing surfaces and made of a fluororesin containing at least carbon fiber or carbon powder. (2) The ultrasonic motor device according to claim 1, wherein the carbon fibers included in the friction means are in the form of a woven fabric. (3) The ultrasonic motor device according to claim 1, wherein the carbon fibers included in the friction means have a felt-like form.