JPH03178578A - Vibration wave motor - Google Patents

Abstract

PURPOSE:To prevent production of abrasion dust and irritation of a sliding surface due to chipping of a vibrator by carbon fiber, to reduce irregularity of the output of a vibration wave motor, and to improve durability of the motor by making the hardness of a sliding member of a vibrator not less then Hv 600. CONSTITUTION:The upper surface of comb-teeth of a friction-contact surface has a hardened section 1c with a coat having Vickers hardness not less than Hv 600. The sliding surface of a vibrator 1 and a sliding member 2b of a mover 2 are in pressure-contact with each other by applying an axial force of, for example, 10kgf. by a pressing means not shown. An AC voltage at the frequency inherent to the vibrator 1 is applied to two groups of piezoelectric elements 1a consisting of piezoelectric elements polarized alternately in the thickness direction. And, then, the vibrator 1 resonates and a progressive vibration wave is generated in the direction toward the sliding surface and the mover 2 in pressure-contact with the surface of the vibrator 1, rotates by a friction force produced between the sliding surfaces of the vibrator 1 and the sliding member 2b.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention applies a voltage to an electro-mechanical energy conversion element, and uses vibration waves generated in a vibrating body to frictionally drive, for example, a member that comes into pressure contact with the vibrating body. This relates to a vibration wave motor.

[Prior Art] The basic principle of a vibration wave motor using progressive vibration waves is as follows.

A stator is a ring-shaped elastic body made of an elastic material whose total circumference is an integral multiple of a certain length λ, and a group of piezoelectric elements arranged in the circumferential direction are fixed to one side of the ring-shaped elastic body. . These piezoelectric elements are arranged at a pitch of λ/2 within each group so that they alternately have opposite expansion and contraction polarities, and are arranged so that there is a shift of an odd multiple of λ/4 between the two groups. has been done. Both groups of piezoelectric elements are provided with electrode films, respectively.

If an alternating current voltage is applied only to one of the groups (hereinafter referred to as A phase), the elastic body will move to the center point of each piezoelectric element of the word group and every other point from there to the antinode position, or A standing wave of bending vibration (
wavelength λ) is generated over the entire circumference of the elastic body. Another group (
If an AC voltage is applied only to the B phase (hereinafter referred to as the B phase), a standing wave will similarly be generated, but the positions of the antinodes and nodes will be shifted by λ/4 with respect to the standing wave due to the A phase. When AC voltages with the same frequency and a temporal phase difference of 90° are simultaneously applied to both A and B phases, as a result of the synthesis of both standing waves, bending vibration vibrates in the circumferential direction in the elastic body. A traveling wave (wavelength λ) of Therefore, if a rotor, such as a ring-shaped movable body, is brought into pressure contact with each other surface of the elastic body, the movable body receives circumferential friction from the elastic body and is rotationally driven.

Therefore, since the sliding surface where the elastic body and the movable body come into contact continues to receive continuous frictional force, the movable body is made of a composite resin filled with carbon fiber that slides against the elastic body made of metal. It was designed to adhere as a material, stabilize frictional force, and reduce wear to ensure improved performance and long life.

[Problems to be Solved by the Invention] However, in the above conventional example, the elastic body is made of austenitic Stair 1/S 5US303, Vickers hardness (IV) approximately 230), and the sliding material on the moving body side is made of P.
When a thermoplastic resin (polyether ether ketone) filled with 0 wt % of AN-based carbon fibers was used and the motor was driven, the rotation became unstable after about 10 hours of operation, and abnormal noises were frequently generated. Observation of the contact surface after driving for 50 hours revealed that there were quite deep scratches on the sliding surface of the elastic body 5115303, and elemental analysis of the sliding surface on the movable body side detected iron. This is thought to be because the stainless steel was worn away by the drive and abrasion powder was scattered on the sliding surface, making rotation unstable, and the abrasion powder became embedded in the relatively soft resin.

An object of the present invention is to provide a vibration wave motor that can stabilize the output and also ensure sufficient durability.

[Means and effects for solving the problem] By observing the friction surface, the present inventor discovered that the above-mentioned phenomenon that occurred in conventional vibration wave motors was caused by the so-called ablation caused by carbon fibers cutting softer stainless steel. 1/ Judging that it is abrasion, the hardness of the friction sliding part on the vibrating body side is set to H.
By setting v600 or higher, carbon fiber can prevent the generation of abrasion powder and roughness of the sliding surface caused by scraping the vibrating body, reduce uneven output of the vibration wave motor, and increase durability. This led to the invention.

The carbon fiber constituting the sliding material may be either a PAN-based high-strength type or a pitch-based high-elasticity type, and has a carbon fiber of 5 to 35%.
By filling the resin, it works to increase the mechanical strength and thermal conductivity of the resin, thereby increasing its abrasion resistance. The base material resin may be a thermosetting resin such as polyimide, epoxy, or phenol, or a thermosetting resin such as polyamide, polyacetal, polyamideimide, polyetherimide, polyetheretherketone, polyethersulfone, polyphenylene sulfide, or modified polyphenylene sulfide. Liquid crystal polymers such as thermoplastic resins with high mechanical strength and heat resistance or aromatic polyesters,
Polymer alloys thereof are desirable. In addition, the friction sliding surface on the elastic body side can be formed using methods that harden the surface of the elastic body itself, such as penetration diffusion methods such as carburizing, nitriding, and sulfurization, hardening with high frequency, laser, etc., vapor deposition methods such as CVD, PVD, and arc A hardened surface layer is formed by a method of coating the surface with a hard material, such as thermal spraying using a laser or plasma, or various types of plating such as electrolytic and electroless plating. In particular, carbonized ceramics such as WC, Tic, and SiC, or cermet coatings of Co and Ni, which have particularly high surface toughness,
Using Ni, Go, Cr, etc. as the matrix metal,
Sin, TiG, WC, A1203St (h, T
Composite plating of particles such as i(h) has good adhesion to the metal of the elastic body, improves wear resistance, and has a rust-preventing effect, so it can be expected to have a long life.

[Embodiments] The present invention will now be described in detail based on embodiments shown in the drawings.

FIG. 1 is a sectional view showing an embodiment of a vibration wave motor according to the present invention.

In the figure, reference numeral 1 denotes a flexible ring-shaped metal elastic body 1b made of stainless steel or phosphor bronze, for example, and two groups of piezoelectric elements polarized as described above are formed in a ring shape on one side of the elastic metal body 1b. It is a vibrating body in which a piezoelectric element group 1a is concentrically bonded with a heat-resistant epoxy resin adhesive, and the sliding surface opposite to the bonding surface of the piezoelectric element i1a has a plurality of comb-like shapes to increase the driving speed. Grooves (not shown) are formed at equal intervals in the circumferential direction, and the upper surface of the comb teeth, which is the friction contact area, has a Vickers hardness.
A surface-hardened portion IC is formed as a coating having a hardness of lV600 or higher, and the vibrating body is fixed near the center of the casing (not shown).

2 is a moving device in which a sliding material 2b made of a composite resin filled with ring-shaped carbon fibers is fixed concentrically to one side of a ring-shaped support 2a made of a metal such as an aluminum alloy with an epoxy adhesive or the like. It is the body.

Then, the sliding surface of the vibrating body 1 and the sliding member 2b of the movable body 2 are brought into pressure contact in the axial direction with a load of, for example, 10 kgf by a pressing means (not shown).

When an AC voltage with a frequency specific to the vibrating body 1 is applied to two groups of piezoelectric elements that are alternately polarized in the thickness direction, the elastic body 1 resonates, and the elastic body 1 resonates in the circumferential direction of its sliding surface. A progressive vibration wave is generated, and the movable body 2, which is in pressure contact with the surface of the vibrating body 1, is rotationally driven by the frictional force between the sliding surfaces of the vibrating body 1 and the sliding body 2b.

As a surface hardened portion IC formed on the surface of the elastic body 1b,
Chrome plating (Hv=700), SiC dispersed nickel plating (Iv=600), SiC dispersed nickel plating (annealing) (Hv=9(10), T
ic-Coi radiation coverage DI ()Iv=1100), W
Elastic body 1 b St] using C-Co thermal spray coating (TLV-1300) and surface treatment as a comparative example
53D3 (H, = 230), 5LIS420 ()Iv
=500) to evaluate the surface roughness (R,) and rotational fluctuation before and after driving, respectively.

The sliding material 2b used was a composite resin in which polyether ether ketone was randomly filled with 0 wt % of PAN-based carbon fiber milled fibers.

In addition, the vibration wave motor is driven with a constant amplitude.13
The above evaluation was performed by driving at a rotation speed of 0 to 20 rpm for 50 hours. The results are shown in Table 1.

In Comparative Examples 1.2, 5US303 and 420, after driving, the friction surface of the drive body was severely roughened, the moving body was worn a lot, and the rotation fluctuation gradually became severe.

Although the starting torque of the chrome plate of Example 1 was slightly lower than that of the others, there was no peeling of the plating, little roughness, and little rotational fluctuation.

In Examples 2 to 5, there was almost no peeling or roughness of the surface, and there was no rotational fluctuation.

In this embodiment, PAN-based carbon fibers were used as the filling material for the sliding material on the movable body side, but the same effect can be obtained by using a sliding material filled with pitch-based carbon fibers.

It is also effective to add a solid lubricant (polytetrafluoroethylene, molybdenum dioxide, graphite, mica, talc, etc.) to the sliding material.

In the above embodiments, the vibrating body is fixed and the movable body is moved according to the progressive vibration waves.
The vibrating body itself may be moved by the progressive vibration waves generated on the elastic body, or a composite resin filled with carbon fibers may be fixed to the elastic body side, and the sliding mating member may be moved.
It may be v800 or higher.

[Effects of the Invention] As explained above, according to the present invention, when the frictional sliding material in a vibration wave motor is made of a composite resin filled with carbon fiber, the frictional contact portion of the other side that comes into contact with the sliding material Hv
By setting it to 600 or more, the relative movement surface will not be dug or scraped by the carbon fiber charged in the sliding material, and therefore the surface will be less rough and worn over time.
We were able to obtain a vibration wave motor with stable output and durability.

[Brief explanation of drawings]

FIG. 1 shows a cross-sectional view of an embodiment of a vibration wave motor according to the invention. 1... Vibrating body 1a... Piezoelectric element group 1b
...Metal vibrating body IC...Surface hardened part 2...
Moving body 2a...Support 2b...Sliding material (carbon fiber filled composite resin) 4 people Figure

Claims (1)

[Claims] 1. By applying an alternating current voltage to the electro-mechanical energy conversion element, a progressive vibration wave is formed in the elastic body to which the electro-mechanical energy conversion element is fixed, and thereby the elastic body and , in a vibration wave motor that relatively moves the elastic body and a member in pressure contact with each other by frictional force, one of the contact portions between the elastic body and the member in pressure contact with the elastic body is coated with a resin material. A sliding material filled with carbon fiber is provided, and one of the contact parts between the elastic body and a member that contacts the elastic body under pressure has a Vickers hardness (H
v) A vibration wave motor comprising a hardened portion having a hardness of 600 or more. 2. The vibration wave motor according to claim 1, wherein the hardened portion is a ceramic or cermet coating. 3. The vibration wave motor according to claim 1, wherein the hardened portion is a composite plating layer in which ceramic particles are dispersed.