JP2774613B2 - Ultrasonic motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ultrasonic motor that uses a standing wave type ultrasonic vibration to obtain a rotational force by an elliptical motion.

[Prior Art] Generally, in an ultrasonic motor, as shown in FIG. 3, a sliding member (sliding member) 4 is provided between a moving body 3 and a metal body 2 bonded and fixed to a piezoelectric body 1. Have been.

Conventionally, as the sliding member 4, for example, Japanese Patent Application Laid-Open No. 62-23379
As disclosed in Japanese Patent Application Laid-Open Publication No. H06-163, the use of a thermosetting resin for a felt made of an organic polymer fiber,
As disclosed in Japanese Patent Application No. -58887, one using a composite material of carbon fiber and resin is known. As the organic polymer fiber, various types such as polyamide fiber, phenol fiber, and ceramic short fiber are used. It has also been proposed to use rubber or lubricating oil as the sliding member 4.

[Problems to be Solved by the Invention] However, in the conventional ultrasonic motor, there is no one using a perfect sliding member 4, and after a certain period of time, a phenomenon of generating abrasion powder has occurred. As means for preventing this, tough fibers are contained to improve abrasion resistance, or fine powder is added to promote slidability. However, the form of abrasion generated by the ultrasonic motor is complicated, and a simple sliding friction cannot be used effectively by a sliding member. Therefore, if a tough fiber is contained, the strength is improved, but it does not necessarily mean that the fiber is resistant to abrasion. Similarly, when the sliding member is formed of ceramics, the strength of the sliding member is too high, causing the other member to wear.

Conventionally, the effects of various types of sliding members on the generation of abrasion powder have been proposed, but in any case, abrasion powder is always generated after a lapse of time, and the phenomenon of abrasion is accelerated by the influence of the abrasion powder. It has occurred. That is, the presence or absence of the generation of the abrasion powder greatly affects the life of the ultrasonic motor.

The present invention has been made in view of the conventional problems, and has as its object to provide a practical ultrasonic motor having a long life.

[Means for solving the problem]

In order to achieve the above object, the present invention provides an ultrasonic motor that vibrates a piezoelectric element to excite an elliptical vibration in a vibrating reed, and rotates a rotor pressed against the vibrating reed by the elliptical vibration. A first sliding member and a second sliding member for preventing abrasion are respectively arranged on the mutual press contact surfaces of the rotor, and the first sliding member provided on the vibrating piece side is made of tungsten disulfide. Is formed by paper of alumina short fiber having a heat of 500 μm or less and impregnated with an epoxy resin containing 18 to 22% by weight of a fine powder of the above and 18 to 22% by weight of a fine powder of a phenol resin, and provided on the rotor side. The second sliding member is formed of an amorphous carbon film having a thickness of 300 μm or less and a surface roughness Ra of 0.1 μm or less, obtained by carbonizing an organic material having a single composition.

Further, in the present invention, the first sliding member provided on the vibrating reed side in the above-described configuration is configured such that the fine powder of tungsten disulfide is 18 to
22% by weight and 18-22% by weight of phenolic resin fine powder
The second sliding member formed on the side of the rotor is made of alumina short fiber paper having a thickness of 500 μm or less impregnated with the contained nylon resin. It is formed by immersing molybdenum.

Further, according to the present invention, in the above configuration, the first sliding member provided on the vibrating reed side includes a fine powder of molybdenum disulfide of 18 to
22% by weight and 18-22% by weight of phenolic resin fine powder
500μm thickness impregnated with phenol resin
The second sliding member formed of the following alumina short fiber paper and provided on the rotor side is formed by immersing molybdenum disulfide by treating the end face of the rotor with manganese phosphate.

Still further, in the present invention, the first sliding member provided on the vibrating reed side is formed of an aluminum composite material containing ceramic-based short fibers.
The second sliding member provided on the rotor side is formed by carbonizing an organic material having a single composition and has a thickness of 300 μm or less and a surface roughness Ra =
It is formed of an amorphous carbon film having a thickness of 0.1 μm or less.

In the present invention, the weight ratio of each fine powder of tungsten disulfide, molybdenum disulfide and phenol resin is defined as
The reason for setting the content to 18 to 22% by weight is that if the content is less than 18%, the temperature rises during driving, a sound is generated, and the subsequent rotation becomes unstable and stops. If it is more than 22%, the strength of the alumina short fiber paper decreases,
This is because breakage occurs due to driving (vertical and horizontal vibrations), which makes the rotation unstable and stops.

Also, the thickness of the alumina short fiber paper on the vibrating piece side and the thickness of the carbon film on the rotor side were limited respectively.
If the thickness is large, the vibration is attenuated while the vibration is transmitted from the vibrating piece to the rotor, and the transmission of torque is reduced.

FIG. 1 is a conceptual diagram of an ultrasonic motor according to the present invention. Between two resonators 5, electrode plates 6 and piezoelectric elements 7 are alternately stacked. Further, a resonator element 8 is laminated on one resonator 5, and a rotor 9 is laminated on the resonator element 8. These components are fastened and fixed by fixing bolts 10. Further, a first sliding member is provided between the vibrating bar 8 and the rotor 9 on the vibrating bar 8 side.
11 is provided, and a second sliding member 12 is provided on the rotor 9 side. Here, the sliding members 11 and 12 are configured by the combination as described above.

[Operation] According to the ultrasonic motor of the present invention having the above configuration, generation of wear powder is extremely small. Therefore, the promotion of wear by the wear powder does not occur. Compared to the case where only the resin is used as the sliding member, the contact surface of the vibrating piece 8 with the resin shines glossy after the initial wear, and a lubricating boundary layer is formed by friction. When the lubricating boundary layer is formed, the generation of abrasion powder stops and the state becomes stable. In addition, the generation of noise is suppressed by the contained sliding promoter (tungsten disulfide, molybdenum disulfide, phenol). The present invention is particularly effective when the contact area of the vibrating piece 8 with the rotor 9 is very small in an ultrasonic motor using standing wave ultrasonic vibration.

Example (First Example) (Configuration) FIG. 2 shows a main part of an ultrasonic motor according to the present example.

On the vibrating piece 8 side, as the first sliding member 11, an alumina resin impregnated with an epoxy resin adhesive containing 20% by weight of fine powder of tungsten disulfide and 20% by weight of fine powder of phenol resin is used. Alumina short fiber paper (Fineflex paper, manufactured by Nichias) containing ceramic fine powder of silica is adhered and formed at the contact portion, and after heat curing, is polished to a thickness of 500 μm. The adhesive to be used has been subjected to a defoaming treatment, and there is no air layer in the sliding member 11.

On the other hand, on the rotor 9 side, as the second sliding member 12, a flexible organic material having a thickness of 30 which is obtained by carbonizing an organic material having a single composition is used.
An amorphous carbon film (amorphous carbon, manufactured by Nisshinbo Co., Ltd.) having a thickness of 0 μm and a surface roughness Ra of 0.1 μm is adhered to the contact portion with a low-viscosity epoxy-based adhesive and thermally cured.

(Operation) In the first sliding member 11 on the vibrating piece 8 side, the fine powder of tungsten disulfide contained in the resin-impregnated alumina short fiber paper serves to promote vibration, 20 resin fine powder to epoxy resin
The one containing by weight has a function of preventing generation of sound. The strength of the sliding member 11 itself is maintained by the alumina short fibers, and after initial wear, a glossy lubricating boundary layer is formed on the contact surface. Further, the ceramic fine powder of alumina and silica in the paper of the short alumina fiber has a particle size of about 50 μm, and the amount of wear is very small as compared with the resin. After the initial wear, when exposed to the contact surface, the amount of wear of the sliding member 11 on the vibrating piece 8 side is regulated by the amount of wear of the ceramic fine powder.
The wear resistance is improved.

The amorphous carbon film, which is the sliding member 12 on the rotor 9 side, is formed by carbonizing an organic material having a single composition, and is very tough and has a fine structure. In addition, since the vibrating piece 8 has a certain degree of flexibility, the vibrating piece 8 is deformed along the shape of the vibrating piece 8 to easily receive a rotational force. Furthermore, since it is carbon, the slidability is good and the wear resistance is excellent.

(Effect) When a sliding member made of only resin is used together with an amorphous carbon film, abrasion resistance after initial abrasion can be improved. The surface roughness of the contact surface is very small,
The generation of wear powder which causes the progress of wear is suppressed, and the generation of noise can be completely eliminated. Further, since the sliding members 11 and 12 have high hardness, it is possible to minimize the decrease in torque due to the lubricant.

It should be noted that, instead of the second sliding member 12 of the present embodiment, the rotor 9 having a contact surface formed into a mirror surface and then subjected to chromium nitride treatment was impregnated with resin in the same manner as in the present embodiment. A lubricating boundary layer is formed on the contact surface of the alumina short fiber paper,
Wear can be prevented.

Second Embodiment (Configuration) On the vibrating piece 8 side, as a first sliding member 11, a nylon 66 resin containing 20% by weight of a fine powder of molybdenum disulfide and 20% by weight of a fine powder of a phenol resin is used. Alumina short fiber paper (Nichias Fine Fine Rex paper) containing ceramic fine powder of alumina and silica, which is impregnated with aluminum, is adhered to the contact area with an epoxy adhesive, cured by heat, and then polished to a thickness. Is 500 μm. The adhesive to be used has been subjected to a defoaming treatment, and there is no air layer in the sliding member 11.

On the other hand, the rotor 9 has a hardness obtained by heat-treating the alloy tool steel.
The second sliding member 12 is formed of a material of Hv 650 or more, after processing the contact portion into a mirror surface, performing manganese phosphate treatment at a depth of 10 μm, and immersing molybdenum disulfide.

(Operation) As in the first embodiment, a glossy lubricating boundary layer is formed on the contact surface of the alumina short fiber paper impregnated with the resin. Further, the slidability is further promoted by molybdenum disulfide immersed in the rotor 9.

(Effect) In addition to the slidability of molybdenum disulfide, the contact surface is close to a mirror state, so that scratches due to abrasion do not occur and generation of abrasion powder can be prevented. Like the epoxy resin, the nylon resin also forms a lubricating boundary layer on the contact surface, improves the abrasion resistance after the initial abrasion, and hardly causes abrasion. Generation of noise is suppressed by molybdenum disulfide, and stable rotation is obtained. Further, the rotor 9 can be manufactured relatively easily without any bonding work. Therefore, it is suitable for mass production and cost can be reduced.

In addition, instead of the nylon 66 resin in this example,
Similar effects can be obtained by using a nylon 6 resin or a thermosetting resin phenol resin.

(Third Embodiment) (Structure) On the vibrating piece 8 side, an aluminum composite material containing short fibers of alumina is formed on the contact portion by brazing, and then the contact surface is mirror-polished by polishing, and the thickness is increased. The first sliding member 11 is formed with a height of 500 μm.

On the other hand, on the rotor 9 side, as the second sliding member 12, a flexible organic material having a thickness of 30 which is obtained by carbonizing an organic material having a single composition is used.
An amorphous carbon film (amorphous carbon, manufactured by Nisshinbo Co., Ltd.) having a thickness of 0 μm and a surface roughness Ra of 0.1 μm is adhered to the contact portion with a low-viscosity epoxy-based adhesive and thermally cured.

(Operation) The sliding member 11 on the side of the vibrating reed 8 is made of the same material as the vibrating reed 8 and is bonded by brazing instead of bonding.
It is difficult to attenuate the elliptical vibration at the tip of the resonator element 8. Further, the strength of the sliding member 11 is maintained by the alumina short fibers, and the sliding member 11 is hardly worn. Further, since the carbon film is used as in the first embodiment, the slidability is improved.

(Effect) Since the elliptical vibration can maintain a strong state, rotation with high torque can be obtained. Sound generation is reduced by carbon, and rotation can be stabilized.

In place of the carbon film, after heat-treating the alloy tool steel and processing the contact portion of a material having a hardness of Hv 650 or more into a mirror surface, manganese phosphate treatment was performed at a depth of 10 μm, and molybdenum disulfide was immersed. Even when used, the abrasion resistance is similarly excellent and the slidability can be improved.

〔The invention's effect〕

According to the present invention, the first sliding member on the vibrating reed has strength, and the first sliding member is combined with the second sliding member on the rotor side to form the first sliding member. A lubricating boundary surface is formed on the contact surface of the member after the initial wear, the wear resistance after the initial wear is improved, and generation of wear powder can be prevented. Also,
The first sliding member can effectively prevent generation of sound.
Thus, stable rotation of the rotor can be maintained, and a long-life and practical ultrasonic motor can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an ultrasonic motor according to the present invention, and FIG.
FIG. 1 is a perspective view showing a main part of an ultrasonic motor according to a first embodiment of the present invention, and FIG. 3 is a longitudinal sectional view showing a main part of a conventional ultrasonic motor. 5 Resonator 6 Electrode plate 7 Piezoelectric element 8 Vibrating piece 9 Rotor 10 Fixing bolt 11 First sliding member 12 Second sliding member

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02N 2/00-2/18

Claims (4)

(57) [Claims] 1. An ultrasonic motor that vibrates a piezoelectric element to excite an elliptical vibration on a vibrating reed and rotates a rotor pressed against the vibrating reed by the elliptical vibration. A first sliding member and a second sliding member for preventing abrasion are respectively arranged on the pressure contact surface, and the first sliding member provided on the vibrating piece side is made of fine powder of tungsten disulfide. A second slide provided on the rotor side, made of alumina short fiber paper having a heat of 500 μm or less and impregnated with an epoxy resin containing -22% by weight and a phenol resin fine powder in an amount of 18-22% by weight. The moving member is formed by carbonizing an organic material having a single composition and has a thickness of 300 μm or less and a surface roughness R.
An ultrasonic motor formed of an amorphous carbon film having a = 0.1 μm or less. 2. An ultrasonic motor that vibrates a piezoelectric element to excite an elliptical vibration in a vibrating reed, and rotates a rotor pressed against the vibrating reed by the elliptical vibration. A first sliding member and a second sliding member for preventing abrasion are respectively arranged on the press contact surface, and the first sliding member provided on the vibrating piece side is made of a fine powder of molybdenum disulfide. Formed of a short-fiber alumina paper having a thickness of 500 μm or less and impregnated with a nylon resin containing about 22% by weight and 18 to 22% by weight of a fine powder of a phenol resin, and a second slider provided on the rotor side. An ultrasonic motor, wherein the moving member is formed by immersing molybdenum disulfide by treating the end face of the rotor with manganese phosphate. 3. An ultrasonic motor which vibrates a piezoelectric element to excite an elliptical vibration in a vibrating reed, and rotates a rotor pressed against the vibrating reed by the elliptical vibration. A first sliding member and a second sliding member for preventing abrasion are respectively arranged on the press contact surface, and the first sliding member provided on the vibrating piece side is made of a fine powder of molybdenum disulfide. Formed of a short-fiber alumina paper having a thickness of 500 μm or less impregnated with a phenol resin containing -22% by weight and a phenol resin fine powder of 18-22% by weight, and a second slider provided on the rotor side. An ultrasonic motor, wherein the moving member is formed by immersing molybdenum disulfide by treating the end face of the rotor with manganese phosphate. 4. An ultrasonic motor that vibrates a piezoelectric element to excite an elliptical vibration on a vibrating reed and rotates a rotor pressed against the vibrating reed by the elliptical vibration. A first sliding member and a second sliding member for preventing abrasion are respectively arranged on the pressure contact surface of the above, and the first sliding member provided on the vibrating piece side contains a ceramic short fiber. The second sliding member provided on the rotor side is formed by carbonizing an organic material having a single composition and has a thickness of 300 μm or less and a surface roughness R
An ultrasonic motor formed of an amorphous carbon film having a = 0.1 μm or less.