JPH0398476A - Lining member for ultrasonic wave driving motor, and ultrasonic wave driving motor using same - Google Patents

Abstract

PURPOSE:To provide abrasion resistance and eliminate the generation of noise by forming a lining member of substance having the continuous porosity of 3-40% and having the Rockwell M hardness and dynamic friction coefficient in a specific range. CONSTITUTION:An ultrasonic wave driving motor consists of a stator section 1 and a rotor section 2, and by oscillating the the oscillation amplifying section 5 which in the projected section of a driving body 4, the rotor section 2 is driven via a lining member 9. The lining member 9 is formed of material having the continuous porosity of 3-40%, and having he Rockwell M hardness of 20-110, the dynamic friction coefficient of 0.10-0.50, and 2 or less of the value of a static friction coefficient divided by the dynamic friction coefficient, e.g. a polyamide. As a result, the vertical oscillation of a stator is properly absorbed, and rotational component only can be effectively taken out.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a lining material used in, for example, an ultrasonic drive motor that uses ultrasonic vibration as a driving source to cause resonance in an elastic body and converts the resonance motion into rotational motion. It is related to.

Conventional technology A piezoelectric drive motor uses piezoelectric vibration as an excitation part to cause resonance in a solid body and convert the vibration into rotational motion.
The so-called ultrasonic drive motor is characterized by its simple structure, and is expected to have a wide range of applications such as electronic equipment, cameras, and medical equipment. However, since the ultrasonic drive motor converts ultrasonic vibration into rotational motion or the like, friction between the two contacting media inevitably occurs at the part where the vibrational motion is converted into rotational motion or the like. In order to prevent noise caused by friction, a proposal has been made to use a synthetic polymer having a Rockwell M hardness of 20 to 8o. 〈Unexamined Japanese Patent Publication No. 62-2010
No. 73> Problems to be Solved by the Invention Although noise reduction can be achieved to some extent by using the above-mentioned lining material, the resin in that hardness range is either a rubber elastic body or a mixture of a rubber elastic body and phenol, epoxy resin, etc. However, such resin compositions have a large amount of wear,
There is a problem with practical durability.

In order to solve these drawbacks, the present invention has excellent wear resistance,
The object of the present invention is to provide a lining material that does not generate noise and achieves high torque.

Means for Solving the Problems In order to solve the above problems, the lining material for an ultrasonic drive motor of the present invention has a Rockwell M hardness of 20 to 110, a dynamic friction coefficient of 0.10 to 0.50, and a static friction coefficient of 20 to 110. The coefficient divided by the dynamic friction coefficient is 2.0 or less, 3 to 40
% of the porosity.

Effects According to the above configuration, the lining material for an ultrasonic drive motor of the present invention has excellent wear resistance and a moderate coefficient of friction, making it difficult for the so-called stick-slip phenomenon to occur, and also having moderate hardness and bending elastic modulus. Sliding noise at high speeds is also reduced.

EXAMPLE Next, an example in which the lining material of the present invention is used in an ultrasonic drive motor will be described with reference to FIG.

Basically, an ultrasonic drive motor consists of a stator section 1 and a rotor section 2. The stator section 1 is composed of a piezoelectric body 3 serving as an excitation section and a driving body 4 made of iron or other metal material to which the piezoelectric body 3 is bonded. Now, the piezoelectric body 3 is polarized into N pieces, and each adjacent electrode has +
By applying an electric field of , -, the ring-shaped maximum deformation part located at a certain radius from the center of the disk where the piezoelectric body 3 and driving body 4 are bonded together as shown in Fig. 3 becomes as shown in Fig. 3. The entire ring vibrates in a wavy manner, vibrating the vibration amplification section 5, which is a protrusion provided at the maximum deformation section of the drive body 4, and thereby causing the rotor section 2 to vibrate through the lining material 9 that contacts the vibration amplification section 5. to drive. In FIG. 1, 6 is a stator support part, 7 is a stator fixing base, and 8 is a rotor part 2.
10 is a bearing, and 11 is a nut that is screwed onto the shaft 8 via a disc spring 12 and brings the stator section 1 and rotor section 2 into contact with each other under a predetermined pressure.

To explain the driving principle of this motor, by applying a voltage to the piezoelectric body 3 of the stator section 1, the vibration amplifying section 5 of the driving body 4 made of iron or the like is vibrated.

This vibration amplification part 5 has vibration components in the axial direction and the circumferential direction, and each part of the vibration amplification part 5 produces vibrations that describe an elliptical locus. At this time, when the lining material 9 provided on the driven surface of the rotor section 2 is brought into contact with the vibration amplifying section 5, the rotor section 2 absorbs the axial component and rotates in one direction due to the circumferential component. An ultrasonic drive motor is realized by extracting the rotation of the rotor section 2 to the outside.

The present invention is based on the recognition that in such an ultrasonic drive motor, the combination of materials of the vibration amplifying part 5 of the stator part 1 and the driven surface, that is, the lining material 9, is important, and it is possible to moderate the vertical vibration of the stator. The lining material contains 3% to 4% of
It has been devised to have a porosity of 0%. If the porosity is less than 3%, the vibration absorbing ability will be low and noise will be generated.

On the other hand, if the porosity is greater than 40%, the motor torque will drop significantly and the motor locking characteristics will deteriorate.

The motor lock characteristic means that when the motor is left in a stopped state for a long period of time, the vibration amplification section bites into the lining material, making it impossible to start the motor. Due to the cushioning effect of the voids, the lining material of the present invention has a Rockwell M hardness of 11.
No noise is generated over a wide hardness range of 0 or less. When the Rockwell M hardness is 20 or less, torque characteristics and motor lock characteristics deteriorate.

In order to achieve even higher motor torque, a dynamic friction coefficient of 0.1 or more is required. However, if the coefficient of dynamic friction exceeds 0.5, the amount of wear increases, making it impractical.

Also, the ratio of static friction coefficient to dynamic friction coefficient is 2. If the temperature exceeds 0, a stick-slip phenomenon occurs, causing uneven rotation of the motor.

Next, the manufacturing method of the lining material of the present invention involves dispersing fibers, pulp, and particles in water, making paper from the aqueous slurry, laminating the obtained paper and hot-pressing it, and using two or more types with different melting points. A method of hot-pressing a nonwoven fabric or felt made of fibers at a temperature that allows the low-melting component to be deformed, or a method of mixing two or more powders with different melting points and hot-pressing the mixture at a temperature that allows the low-melting point component to deform. etc., but
The method is not limited to this method.

Since the lining material of the present invention has voids, the dissipation of heat generated by sliding becomes worse. Therefore, materials with good heat resistance are appropriate.

Although not specified as organic and/or inorganic heat-resistant materials, examples of organic heat-resistant materials include polyimide, polyether ether ketone, boris sulfone, and polyphenylene sulfide. Polyoxybenzylene, polyphenylene oxide, polyether sulfone, polyarylate, polyetherimide, bismaleimide triazine resin, polyamideimino, polyamino bismaleimide, polybutylene terephthalate, polyethylene terephthalate, polycarbonate, polyacetal, polyamide, epoxy resin, phenol Resin, unsaturated polyester, diallyl phthalate resin, silicone resin, fluororesin, ABS
Examples include resin, high molecular weight polyethylene, acrylic resin, polyurethane, furan resin, melamine resin, urea resin, and the like.

In addition, as inorganic heat-resistant materials, glass fiber (chopped strand, glass wool, milled fiber, etc.), kaolin fiber, alumina fiber, silica fiber, silica. Alumina fiber, rock wool fiber, titanium oxide fiber, potassium titanate fiber, bauxite fiber, kyanite fiber, boron-based fiber, gypsum needle crystal, magnesia fiber, metal fiber (iron-based, brass, stainless steel, copper, etc.), dolomite Powder, dawsonite (fibrous, powder), calcium silicate (
fibrous, powder), gypsum powder, kaolin powder, talc, mica, magnesium oxide and/or magnesium hydroxide, glass powder, metal powder, silicate powder, alumina powder, jadeite powder, barite powder, cryolite Examples include powder, calcium carbonate, etc.

In addition, graphite, molybdenum disulfide, tungsten disulfide, boron nitride, graphite fluoride, metal oxides (lead monoxide, molybdenum trioxide,
Cobalt trioxide, zinc oxide, tin oxide, steel oxide, cadmium oxide, tungsten trioxide, dilanthanum trioxide, triiron tetroxide, etc.), metal fluorides (calcium fluoride, barium fluoride, lithium fluoride, fluoride, etc.) sodium chloride, etc.
Silicon nitride, fluororesin, etc. may be mixed.

Table 1 shows the properties of lining materials prepared by various methods. In the table, Rockwell M hardness is JIS K 7 2
The coefficient of friction was determined by the method specified in 0.2, and the friction coefficient was measured by applying a hardened steel surface with a Rockwell C scale hardness of 62 and a surface roughness of 2S to a sample with a 2 cm x 2 cm flat surface.
The measurement was carried out by applying a load of 50 g and moving at a speed of 5 m/win.

The porosity is calculated by comparing the apparent specific gravity of the sample with the specific gravity of the material surrounding the sample.

An experiment was conducted by attaching the lining materials shown in Table 1 to an ultrasonic drive motor. The properties of the piezoelectric ceramic used are shown in Table 2, and the motor shown in Table 3 was used. The results are shown in Table 4.

In Table 4, the amount of wear is determined by measuring the thickness of the lining material after driving for 5008 hours at 50 rpm and comparing it with the initial value. The operating noise is 50rpm and the motor makes 4.
Cra If! This is the sound pressure level measured with a microphone installed at a certain position. In addition, the starting torque is the maximum torque when energized, and low-speed rotation unevenness was visually determined to see if the rotation was smooth during operation at 0.5 to 1 rpm.

(Left below) Table 2 Table 4 Effect of the Invention From the results in Table 4, it is clear that the material has a continuous void of 3 to 40%, a bending modulus of elasticity of 150 to 400 kg/m-, and a coefficient of dynamic friction. An ultrasonic drive motor is characterized in that it is equipped with a lining material having 3 to 40% pores with a value of 0.10 to 0.50 and a value obtained by dividing the static friction coefficient by the kinetic friction coefficient of 2.0 or less. Durable, quiet operation, and
Stable rotation with high torque is possible. It also has sufficient motor locking characteristics and is extremely useful as a practical motor.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an ultrasonic drive motor according to an embodiment of the present invention, and FIGS. 2 and 3 are cross-sectional views showing the vibration state of a stator portion of the same motor. 1... Stator part, 2... Rotor part,
3... Piezoelectric body, 4... Drive body, 5...
... Vibration amplification section, 9 ... Lining material.

Claims (2)

[Claims] (1) 3 to 40% voids with a Rockwell M hardness of 20 to 110, a dynamic friction coefficient of 0.10 to 0.50, and a value obtained by dividing the static friction coefficient by the dynamic friction coefficient of 2.0 or less Lining material for ultrasonic drive motors with a (2) A stator portion having an excitation portion having a vibration component and forming a drive surface having wear resistance and toughness, and a driven surface that is softer than the drive surface and has wear resistance in contact with the drive surface. In an ultrasonic drive motor having a rotor portion, the driven surface has a Rockwell M hardness of 20
~110 and a dynamic friction coefficient of 0.10 to 0.50
An ultrasonic drive motor equipped with a lining having a porosity of 3 to 40% and a value obtained by dividing a static friction coefficient by a dynamic friction coefficient of 2.0 or less.