JPH09163763A - Ultrasonic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic motor which can generate a stable and high torque with good efficiency for a long period by a method wherein a slider material which is provided with prescribed characteristics in a well- balanced manner is found out and the slider material is used. SOLUTION: In an ultrasonic motor, an ultrasonic vibrating body 1 which generates traveling waves at least on the surface comes into contact with a slider material 3 at a moving body, and the moving body is driven by the traveling waves by a frictional force between both. In the ultrasonic motor, the slider material 3 is formed of an acrylonitrile butadiene-based rubber as a first essential component, of a tetrafluoroethylene-based resin powder as a second essential component and of a lubricative rubber component, containing spherical graphite, as a third essential component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor for generating a driving force on a moving body provided on a vibrating body by using a piezoelectric body to generate ultrasonic vibration accompanied by a traveling wave, and particularly, in the moving body. The present invention relates to an ultrasonic motor having an improved slider material that constitutes a portion that contacts the vibrating body.

[0002]

2. Description of the Related Art Generally, a traveling wave type ultrasonic motor has a structure in which an ultrasonic vibrating body equipped with a piezoelectric body and a moving body are brought into pressure contact with each other, and the moving body is moved by a frictional force between the vibrating body and the moving body. Driven. In the ultrasonic motor having such a mechanism, in order to improve the driving force of the moving body, it is necessary that the frictional force between the moving body and the vibrating body is large and the pressure contact force is large. Therefore, the slider material provided in the contact portion with the vibrating body in the moving body is required to have a large and stable friction coefficient, excellent wear resistance, and no friction noise.

In the presence of such a demand, a resin composition containing a carbon fiber as disclosed in JP-A-62-58887 as a conventional slider material, JP-A-63-12.
The polyimide-based resin containing aromatic polyamide fiber or carbon fiber disclosed in Japanese Patent No. 1480 can be used.

[0004]

However, all of the above conventional materials are stable in friction coefficient, wear resistance, and
In addition, the suppression of frictional noise was not all well-balanced. In particular, the vibrating body to be contacted is
When formed of a soft metal such as stainless steel, phosphor bronze, aluminum, or a copper alloy, a slider material containing a fibrous filler damages the vibrating body, which is not preferable. further,
The conventional slider material has a problem in terms of fatigue wear property in long-term use.

Therefore, an object of the present invention is to find a slider material having all of the following characteristics in a well-balanced manner, and by using such a slider material, it is possible to efficiently generate a stable high torque for a long period of time. It is to provide an ultrasonic motor. The properties to be resolved are:

(1) The friction coefficient is relatively large and stable even if the pressure contact force is small. (2) Excellent wear resistance, especially fatigue wear resistance in long-term use. (3) The generation of frictional noise is small, and damage to the contact partner can be suppressed.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, an ultrasonic vibrating body for generating a traveling wave is brought into contact with a slider member of a moving body at least on the surface thereof, and a frictional force between them is generated. In the ultrasonic motor that drives the moving body by the traveling wave, the slider material is acrylonitrile butadiene rubber that is the first essential component, tetrafluoroethylene resin powder that is the second essential component, and the third essential component. That is, a structure made of a lubricating rubber composition containing spheroidal graphite was adopted.

Since the slider material made of the lubricating rubber composition is used, the friction coefficient is relatively large and stable even when the pressure contact force is small. Further, it is excellent in wear resistance, and in particular, damage to the contact partner can be suppressed to be small. With these, it is possible to efficiently and stably generate high torque for a long period of time.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the portion of the ultrasonic motor according to the present invention at which the ultrasonic vibrating body contacts the moving body has a structure in which the moving body 2 is provided on the ultrasonic vibrating body 1 having the piezoelectric body 1a. In addition, a slider material 3 is provided on a portion of the moving body 2 that contacts the ultrasonic vibrating body 1. Since the ultrasonic vibrating body 1 and the slider material 3 face each other and are in pressure contact with each other, the surface traveling wave generated by the piezoelectric body 1a is transmitted to the ultrasonic vibrating body 1 and the ultrasonic vibrating body 1 and the slider. The moving body 2 is driven by the frictional force with the material 3.

The slider material 3 is a lubricating rubber composition containing acrylonitrile butadiene type rubber which is the first essential component, tetrafluoroethylene type resin powder which is the second essential component, and spherical graphite which is the third essential component. It consists of

The acrylonitrile-butadiene rubber (hereinafter referred to as NBR), which is the first essential component, is a copolymer of butadiene and acrylonitrile and is synthesized by various organic synthesis methods. Examples of this structure include those having the following (chemical formula 1) as a main structural unit.

[0013]

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(M and n are integers.) The NBR may be any NBR as long as it has rubber-like elasticity at room temperature. Particularly, when changing the physical properties of NBR, It is preferable that the amount of acrylonitrile is in the range of 15 to 50% by weight. Generally, NBR having an acrylonitrile amount of less than 24% by weight is a low nitrile NBR, and NBR having an acrylonitrile amount of 24 to 30% by weight is a medium nitrile NBR and an acrylonitrile amount of 3
0-36% by weight NBR is medium-high nitrile NBR, and acrylonitrile amount 36-42% by weight NBR is high-nitrile NBR.
BR, NBR having an acrylonitrile content of more than 42% by weight can be classified as an extremely high nitrile NBR. In order to increase wear resistance, aging resistance, and tensile strength, it is better to use a large amount of acrylonitrile, but in order to keep rubber elasticity, cold resistance, and low-temperature properties at a level not impaired, the amount of acrylonitrile should be about 2
Range of 4 wt% or more and 42 wt% or less, or about 24 wt%
It is preferable to use a NBR which exceeds the range of less than 42% by weight, that is, which belongs to the medium nitrile NBR to the high nitrile NBR.

The weight average molecular weight of the NBR is not particularly limited, but it is preferably 50,000 or more, and those having a high molecular weight as much as possible can obtain good results, and therefore, 70,000 or more is preferable, Those of 100,000 to 500,000 are particularly preferable.

Examples of such NBR are: JSR-N manufactured by Japan Synthetic Rubber Co., Ltd., NIPOL manufactured by Nippon Zeon Co., Ltd.
Goodyear company make: CHEMIGUM etc. can be illustrated.

The above-mentioned second essential component, tetrafluoroethylene-based resin powder, means, for example, a powder made of the following tetrafluoroethylene-based resin.

Examples of the tetrafluoroethylene-based resin include polytetrafluoroethylene (hereinafter referred to as PTF).
Called E. ), Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (referred to as PFA), tetrafluoroethylene-hexafluoropropylene copolymer (referred to as FEP), ethylene-tetrafluoroethylene copolymer (referred to as ETFE). ),
Examples thereof include tetrafluoroethylene-fluoroalkyl vinyl ether-fluoroolefin copolymer (referred to as EPE). In addition, together with these, polychlorotrifluoroethylene (referred to as PCTFE), ethylene-chlorotrifluoroethylene copolymer (referred to as ECTFE), polyvinylidene fluoride (referred to as PVDF), polyvinyl fluoride (PVF). May be mixed with a fluoroethylene resin. These may be used alone or, for example, 1:10.
It may be a fluorinated polyolefin such as the above-mentioned two or more kinds of copolymers or terpolymers in the range of 10: 1 to 10: 1.

Among them, PTFE is a homopolymer of tetrafluoroethylene, has a melting point of about 327 ° C., and is about 340 to 3
Even at 80 ° C, the melt viscosity is as high as about 10 ¹¹ to 10 ¹² poises,
It does not easily flow even when it exceeds the melting point, and is considered to be the most heat resistant resin among fluororesins. Also, P
As the TFE derivative, it is also possible to use PTFE modified with alkyl vinyl ether.

Among the above tetrafluoroethylene-based resins, perfluoro-based tetrafluoroethylene resins such as PTFE, PFA, FEP and EPE have carbon atoms as a skeleton all surrounded by fluorine atoms or a trace amount of oxygen atoms. This is a state, and due to the strong bond between C and F, the fluororesin has a relatively high heat resistance temperature and is excellent in various characteristics such as a low friction coefficient, non-adhesiveness, and chemical resistance.

As the powder of the tetrafluoroethylene-based resin, any of a molding powder produced by a suspension polymerization method and a fine powder produced by an emulsion polymerization method can be used. Crushed and crushed after polymerization, crushed by pressure / heat treatment after polymerization and subjected to γ-ray irradiation treatment or electron beam irradiation treatment, or γ-ray irradiation treatment or electron beam irradiation treatment after polymerization I do not care.

The average particle size of the tetrafluoroethylene-based resin powder is not particularly limited, but is preferably within 20 μm from the viewpoint of rubber elasticity and surface hardness of the molded product, and is 5 to 20.
μm is more preferred. If the average particle size exceeds 20 μm,
There is a risk that rubber hardness will increase and rubber elasticity will be lost.
If it is less than μ, the wear resistance is not satisfied.

Examples of such a tetrafluoroethylene resin powder are: Lubron L10 manufactured by Daikin Co., Fluon G163, Fluon CD1, Asahi Glass Co., Lubricant L169, Lubricant L182J, Mitsui DuPont Fluorochemicals Co., Ltd .: Teflon. 7J etc. can be illustrated.

Among the above tetrafluoroethylene-based resin powders, the tetrafluoroethylene-based resin powders having a carbon material protruding on the surface thereof are more preferable. The tetrafluoroethylene-based resin powder having a carbon material projected on the surface has a structure as shown in FIG. 2, and its production method is, for example, the above-mentioned carbon material at the end of emulsion polymerization in the production of fine powder. Put it in and let it coprecipitate,
A method of obtaining a powder in which the carbon material is projected on the surface of the tetrafluoroethylene-based resin powder by coagulation, washing, and drying, or a dry-mixing of the carbon material with the tetrafluoroethylene-based resin powder containing no carbon material. Then, there is a method in which the carbon material is pierced on the surface of the tetrafluoroethylene-based resin powder to obtain a powder in which the carbon material is projected on the surface of the tetrafluoroethylene-based resin powder.

The above-mentioned carbon material is a powdered material such as general carbon powder or graphite, and graphite is particularly preferable.
Further, it may be HAF, SAF, FEF, MT or the like of carbon black having a large structure which is generally used for rubber materials.

As shown in FIG. 2, the tetrafluoroethylene-based resin powder having the carbon material projected on the surface has the carbon material 7 pierced in all directions in the tetrafluoroethylene-based resin powder 6, so that the inside of the NBR 5 is In, the carbon material 6 has a physical pile effect, and
An affinity occurs between the NBR 5 and the carbon material 7.
Therefore, it is considered that a product having a higher strength than that obtained by simply kneading NBR and tetrafluoroethylene-based resin powder can be obtained.

The spheroidal graphite which is the third essential component is spheroidal graphite or phenolic resin produced as a by-product in the step of spinning from the pitch, which is reacted with paraformaldehyde under a catalyst to polymerize into a sphere. . Also, after that,
Examples include spheroidal graphite that has been fired and crushed.

The primary particle size of the spherical graphite is 1 to 200 μm.
m is preferable, 1 to 40 μm is preferable, and 5 to 40 μm is more preferable. When the particle size is less than 1 μm, even if the spherical graphite is dispersed and mixed in the NBR to expose the spherical graphite on the sliding surface, it will be buried due to elastic deformation due to the pressure of the NBR, and will contact the sliding mating material. This is because it cannot support the load. Further, if the diameter exceeds 200 μm, the smoothness of the surface will deteriorate. Further, when the spherical graphite is kneaded with the NBR, it is necessary that the spherical shape is not destroyed during kneading and has rigidity that does not become fine in order to maintain the wear resistance and friction resistance of the spherical graphite. .

The outer shape of such spherical graphite is not limited to a spherical shape having a smooth surface, but may be one having irregularities on the surface. As a typical example of spherical graphite having a smooth surface, ICB type (graphite, particle size 5 made by Nippon Carbon Co., Ltd.
˜500 μm, specific surface area ≦ 1, bulk specific gravity 0.80 to 0.9
0, true specific gravity 1.35 to 1.40).

A typical example of spherical graphite having fine irregularities on its surface is MC type (graphite, particle size 5
˜30 μm, specific surface area ≦ 10, bulk specific gravity 0.60 to 0.8
0, true specific gravity 1.37 to 1.39).

The method for producing such spherical graphite is not particularly limited, but so-called liquid layer carbonization method or solid layer carbonization method can be used in order to obtain particles having a predetermined primary particle size. Examples of production include the following (1) to (3).

(1) Phenol resin, naphthalene resin,
Furan resin, xylene resin, divinylbenzene polymer,
At least one of styrene-divinylbenzene polymers is used as a starting material, spherical particles are prepared from these materials by a known emulsion polymerization method, and the spherical particles are further treated under an inert atmosphere such as nitrogen gas or argon gas or under vacuum. It is carbonized and graphitized by firing at.

(2) A novolac-type or resol-type phenol resin produced by using a formalin-generating compound for phenols, if necessary, may contain a known filler, as it is, or as a cross-linking agent such as hexamethylenetetramine. Is added and heated to obtain a cured product, which is then pulverized to obtain a predetermined particle size.

(3) Coal tar or coal tar pitch is heated to 350 to 500 ° C. to separate and form spherical graphite produced by the polymerization reaction of low molecular weight substances.

Examples of such spherical graphite include carbon microbeads ICB and MC manufactured by Nippon Carbon Co., Ltd.
Other examples include Bellpearl C-2000 manufactured by Kanebo, Mesocarbon beads manufactured by Osaka Gas Chemicals, and Unibex manufactured by Unitika.

In the present invention, the weight ratio of NBR to tetrafluoroethylene-based resin is 10 parts by weight or more and 10 parts by weight or more of tetrafluoroethylene-based resin to 100 parts by weight of NBR.
It is preferably less than 0 parts by weight. If the amount of the tetrafluoroethylene-based resin is less than 10 parts by weight, sufficient elastic properties cannot be imparted to the elastic rubber composition, and if it exceeds 100 parts by weight, the rubber hardness becomes high and the rubber properties are lost. In addition, the mechanical strength is extremely reduced and it cannot withstand actual use.

The filling weight ratio of the spherical graphite to 100 parts by weight of NBR in the present invention is 5 parts by weight or more and 80 parts by weight or more.
Less than part by weight is preferred. If the spheroidal graphite is less than 5 parts by weight,
Unable to impart sufficient abrasion resistance to the elastic rubber composition,
If it exceeds 80 parts by weight, the rubber hardness becomes high and the rubber properties are lost. In addition, the mechanical strength is extremely reduced and it cannot withstand actual use.

The following compounding agents for rubber and known additives can be compounded within the range not impairing the object of the present invention. As a reinforcing agent, carbon black, silica, clay, calcium carbonate, magnesium hydroxide, aluminum hydroxide, aluminum oxide, talc, mica, kaolin, bentonite, shirasu, wollastonite, silicon carbide, glass powder, carbon powder, boron fiber , Aramid fiber and the like. Examples of vulcanization aids include zinc white and fatty acids. Examples of vulcanization accelerators include guanidines, sulfurs, aldehyde-amines, zincs and the like. Examples of the plasticizer include dimethyl phthalate and dioctyl phthalate. Further, examples of the antiaging agent include amines and phenols. In addition, commonly used antioxidants, UV absorbers,
Flame retardants, colorants and the like can be used.

Further, for the purpose of obtaining releasability during molding and non-adhesiveness of the surface, oil, wax or grease may be added. The blending amount is 2 to 20 parts by weight, preferably 5 to 10 parts by weight based on 100 parts by weight of NBR, which does not affect the mechanical strength of the molded product.

Further, as the solid lubricant, a fluorine-based resin other than the resin used as the tetrafluoroethylene-based resin, for example, when PTFE is used as the tetrafluoroethylene-based resin, ETFE, PFA, F
EP and the like can be added.

The method of kneading the above-mentioned various raw materials is not particularly limited, and a method which is generally widely used,
For example, NBR as the main raw material and other raw materials may be mixed individually or simultaneously with a roll mixer, a propeller mixer, a kneader mixer, or another mixer. At this time, it is preferable to install a temperature controller to prevent heat generation due to friction. Also, when using a roll mixer,
As the finishing mixture, it is preferable that the roll interval is 3 mm or less and the thinning is performed.

Although the lubricating rubber composition of the present invention alone can be used as the molded article, the molded article may be a composite molded article with a metal material or a polymer material depending on the design specifications of parts. In particular, if the polymer material is a composite material having a self-lubricating property, the effect is further exhibited.

In the present invention, an organopolysiloxane containing at least one group selected from a hydroxyl group such as an alcoholic hydroxyl group, an amino group, a carboxyl group, a glycidyl group, and a mercapto group is contained in the above-mentioned lubricating rubber composition. It may be dispersed and held. Such an organopolysiloxane may be a homopolymer of dimethyl siloxane, methylphenyl siloxane, trimethylfluoropropyl siloxane, or the like, or a copolymer of two or more of the above functional groups.

Such an organopolysiloxane is, for example,

[0045]

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(P represents an integer of 1 to 10000) in the main structural unit.

Further, the above-mentioned lubrication is performed with a fluoropolymer containing at least one group selected from hydroxyl groups such as alcoholic hydroxyl groups, amino groups, carboxyl groups, ester groups, isocyanate groups, sulfone groups, epoxy groups, and mercapto groups. It may be dispersed and held in the rubber composition. Such fluoropolymers include polyfluoroalkyl group-containing compounds, polyfluoroethers, and the like, as long as at least one of the above functional groups is introduced.

Such a fluoropolymer is, for example,

[0049]

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(X is an integer of 1 to 4) in the main structural unit. Specifically, a compound 4 such as FOMBLIN Z DISOC manufactured by Montecatini Co.

[0051]

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(M and n are integers).

The number average molecular weight of the organopolysiloxane containing the above functional group and the fluoropolymer containing the above functional group are
About 300 to 10,000, preferably about 1000 to
It may be about 5,000.

[0054]

EXAMPLES First, the basic composition of the lubricating rubber composition used in Examples and Comparative Examples is shown below. The mixing ratios of the respective components are all weight%, but the mixing ratios are based on 100 parts by weight of NBR.

(1) NBR / basic composition A NBR High nitrile type (nitrile content 36 to 42%): JSR 220S 100 parts by weight Sodium stearate general industrial material 1 part by weight Carbon black FEF 30 parts by weight Sulfurization accelerator (1) Ouchi Shinko Chemical Co., Ltd .: TT 2 parts by weight Vulcanization accelerator (2) Ouchi Shinko Chemical Co., Ltd .: M 2 parts by weight Vulcanization aid Zinc oxide activity Zinc white 10 parts by weight Vulcanizing agent Sulfur 1 part by weight Anti-aging agent Amino 3.5 parts by weight-Basic compounding B NBR Nitrile type (Nitrile amount 25-30%) Made by Japan Synthetic Rubber Co., Ltd .: JSR 240S 100 parts by weight stearin Sodium acid General industrial material 1 part by weight Carbon black FEF 30 parts by weight Vulcanization accelerator (1) Ouchi Shinko Chemical Co., Ltd .: TT 2 parts by weight Vulcanization acceleration (2) Ouchi Shinko Chemical Industry Co., Ltd .: M 2 parts by weight Vulcanization aid Zinc oxide 10 parts by weight active zinc white Vulcanizing agent 1 part by weight Sulfur anti-aging agent Amino-based 3.5 parts by weight (2) Tetrafluoroethylene-based resin powder Graphite co-precipitated PTFE (hereinafter referred to as PTFE-1) Graphite having an average particle size of 6 μm and 7:
It was obtained by coprecipitation in a weight ratio of 3 and coagulation and washing. Dry blend PTFE with graphite (hereinafter referred to as PTFE-
No. 2. ) Asahi Glass Co., Ltd .: PTFE Lubricant L182J was dry blended with graphite having an average particle size of 6 μm at a weight ratio of 7: 3 with a Henschel mixer. PTFE (hereinafter referred to as PTFE-3): Asahi Glass Co., Ltd .: PTFE Lubricant L182J ETFE Asahi Glass Co., Ltd .: Aflon COP Z8820 (3) Spherical graphite Kanebo Co., Ltd .: Bell Pearl C2000 (4) Other Silicone Oil Shin-Etsu Silicone Co., Ltd .: KF96 -3
00.

[Examples 1 to 9] First, roll intervals of 5 to 1
Add NBR (220S to the roll mixer adjusted to about 0 mm.
Alternatively, 240S) is wound around, and antioxidant, carbon black, vulcanizing agent and vulcanization accelerator as inorganic fillers are sequentially mixed in the proportions shown in the basic formulations A and B, and finally in the proportions shown in Table 1. Tetrafluoroethylene-based resin powder, spherical graphite and other fillers were kneaded. Then, the roll interval was adjusted to 1 mm, and thin threading was performed 10 times. For the purpose of preventing frictional heat at this time, cooling water was constantly passed through the roll to keep the roll temperature at 60 ° C or lower. Next, cooling water is stopped and steam is passed through the rolls to adjust the NBR material temperature to 70 ° C or higher and 90 ° C or lower, and then the roll interval is narrowed to 1 mm and thin threading is performed 10 times. I got a compound.

For each compound, length 300 mm,
Primary vulcanization (160 ° C., 10 minutes, press pressure 120 k) by press molding using a mold having a width of 300 mm and a thickness of 1 mm.
gf / cm ² ) and secondary vulcanization (free heating, 150 ° C,
4 hours), and the mechanical properties of each sheet after vulcanization were measured. Each test method is as follows.
Further, as an ultrasonic motor mounting test, a mounting material was used for a slider material of a moving body as shown in FIG.

Mechanical Properties The test pieces thus obtained were evaluated for tensile strength, elongation and hardness (JIS-A) according to JIS-K6301. Table 3 shows the results.

Ultrasonic Motor Mounting Test In the ultrasonic motor having the structure shown in FIG. 1, each of the above-mentioned sheet materials having the above composition was mounted as a slider material, a load of 3 kgf / cm ² and a sliding speed of 20 m / min.
Under these conditions, the ultrasonic motor was operated for 100 hours. In such a test, the coefficient of friction of the slider material at the beginning of operation and the coefficient of friction of the slider material after 100 hours of operation were measured, and the wear amount (μm) of the slider material after 100 hours of operation was also measured. . Furthermore, the operation efficiency was measured for the ultrasonic motors on which the respective test pieces were mounted. The operating efficiency (%) is calculated by the following equation: operating efficiency (%) = (output (W) ÷ input (W)) × 100 (Equation 1). In Expression 1, the output (W) was obtained from the rotation speed and torque of the motor. The test results are shown in Table 3.

[Comparative Examples 1 to 5] In the proportions shown in Table 2, mixing, sheet formation, and sleeve test piece molding and vulcanization were performed in the same manner as in the examples. Moreover, the adjustment and test methods of the test pieces were exactly the same as in the examples. Table 4 shows the results.

Comparative Example 6 In the same manner as in Comparative Example 1, a compound of basic composition B of NBR was prepared, and a test piece was obtained by the same method as in Comparative Example. A commercially available coating material for rubber (Emullon 34 manufactured by Nippon Acheson Co., Ltd.) was applied to the obtained test piece.
5) was formed by spray coating to a thickness of about 15 μm. After coating, it was dried and baked in an electric furnace at 80 ° C. for 1 hour to obtain a final test piece. Further, as the evaluation method, the same method as in the example was used. Table 4 shows the results.

[0062]

[Table 1]

[0063]

[Table 2]

[0064]

[Table 3]

[0065]

[Table 4]

As is clear from Tables 3 and 4, Examples 1 to 1
The slider material of No. 9 has a small amount of wear during operation, and maintains a relatively high friction coefficient stably during operation. Further, the slider materials of Examples 1 to 9 hardly damaged the ultrasonic vibration material during the operation of the motor. On the other hand, the slider materials of Comparative Examples 1 to 6 significantly damage the ultrasonic vibration material,
Along with this, the amount of wear of the slider material also increased.

The ultrasonic motors mounted with the slider materials of Examples 1 to 9 exhibit high efficiency, while Comparative Examples 1 to
The efficiency of the ultrasonic motor mounted with the slider material of No. 6 was significantly inferior to those of Examples 1 to 9.

The above embodiment is not intended to limit the present invention, and various slider materials are formed by using the above various materials other than the slider materials of the first to ninth embodiments and mounted on the ultrasonic motor. be able to.

It is to be noted that each composition, each characteristic value, etc., in the range above the lower limit value and below the upper limit value or below the upper limit value or above the lower limit value and below the upper limit value is most suitable for use. It can be appropriately selected to provide a slider material used in an ultrasonic motor.

[0070]

According to the present invention, since the slider material made of the lubricating rubber composition is used, the friction coefficient is relatively large and stable even when the pressure contact force is small.
In addition, it has excellent wear resistance, and in particular, damage to the contact partner can be suppressed to a small level. With these, it is possible to efficiently and stably generate high torque for a long period of time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a contact portion between a moving body and an ultrasonic vibrating body using a slider material made of a lubricating rubber composition of the present invention.

FIG. 2 is a schematic diagram showing a tetrafluoroethylene resin having a carbon material protruding on the surface of an NBR material according to the present invention.

[Explanation of symbols]

 1 Ultrasonic vibrating body 1a Piezoelectric body 2 Moving body 3 Slider material 5 NBR 6 Tetrafluoroethylene resin 7 Carbon material

Claims (5)

[Claims] 1. An ultrasonic motor in which an ultrasonic vibrating body which generates a traveling wave at least on its surface is brought into contact with a slider member of a moving body, and the traveling body is driven by the traveling wave via a frictional force between the two. The slider material is composed of an acrylonitrile-butadiene rubber as a first essential component, a tetrafluoroethylene-based resin powder as a second essential component, and a lubricating rubber composition containing spherical graphite as a third essential component. Ultrasonic motor to do. 2. The tetrafluoroethylene-based resin powder which is the second essential component is a tetrafluoroethylene-based resin powder having a carbon material protruding on the surface obtained by coprecipitation with a carbon material after the completion of emulsion polymerization. The ultrasonic motor according to 1. 3. The tetrafluoroethylene-based resin powder, which is the second essential component, is a tetrafluoroethylene-based resin powder having a carbon material protruding on the surface obtained by mixing the powder with a carbon material by dry mixing. Item 2. The ultrasonic motor according to item 1. 4. The third essential component contains 10 parts by weight or more and less than 100 parts by weight of the second essential component tetrafluoroethylene-based resin powder with respect to 100 parts by weight of the first essential component acrytonitrile-butadiene rubber. The ultrasonic motor according to claim 1, which contains 5 parts by weight or more and less than 80 parts by weight of spherical graphite as a component. 5. The ultrasonic motor according to claim 1, wherein the slider material is a composite of a lubricating rubber composition and a metal or a polymer material.