JP2925192B2 - Vibration wave drive - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vibration wave driving device that relatively moves a vibrating body that generates a vibrating wave and a contact body that presses and contacts the vibrating body by the vibration wave.

(Prior Art) A conventional vibration wave driving device, for example, a vibration wave motor, particularly a large output type vibration wave motor, has a thin ring-shaped piezoelectric element group fixed to the back surface of a ring-shaped vibration substrate made of, for example, stainless steel. At the same time, a super hard material consisting of tungsten carbide and cobalt is sprayed on the surface and further polished to form a hard sliding surface to form a vibrator, while supporting a member such as an aluminum alloy In the body, a thermoplastic resin having a glass transition point of 100 ° C or more, specifically, polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polyetheretherketone (PEEK),
Polyether sulfone (PES), polyarylate (PA
R), heat-resistant resin such as polysulfone (PSF), aromatic polyamide (PA), etc., filled with a reinforcing material such as carbon fiber, and fixed to a sliding body as a reinforced composite resin layer. And a member that comes into contact with the vibrating body is relatively moved by friction drive by a progressive vibration wave generated in the vibrating body.

The relative movement between the contacting member and the vibrating body may be either fixed or moving. However, in the following description of the present specification, the vibrating body will be referred to for simplicity of explanation. It is shown as an example in which the contacting member is fixed and the contacting member is moved. Therefore, the contacting member is referred to as a “moving body”.

In the above conventional vibration wave motor, a glass transition point of 100 is used as a reinforced composite resin layer forming a part of a moving body.
The use of a sliding body whose base material is a thermoplastic resin of ℃ or higher is because these heat-resistant resins have low temperature dependence as material properties and can soften the resin material even when the temperature rises during motor driving. This is because there is no torque-down phenomenon caused and the performance accuracy of the motor can be stabilized.

In addition, the reason that the above-mentioned resin material is mixed and filled with a reinforcing material such as carbon fiber is, firstly, that the moving body has a sliding surface of a cemented carbide material made of, for example, tungsten carbide and cobalt. The purpose of this is to ensure that the properties of the sliding surface are always stable, and that sufficient wear resistance is ensured even when driving for a long time.
The third is to increase the material properties such as the elastic modulus or the hardness of the sliding body to improve the performance of the motor such as the output, and the third is to improve the thermal conductivity of the sliding body to improve the efficiency and the like. This is to improve the performance of the motor.

(Problems to be Solved by the Invention) As described above, in a vibration wave motor, a sliding body providing a sliding surface of a moving body is reinforced by filling a carbon fiber with a heat-resistant thermoplastic resin having a glass transition point of 100 ° C. or more. By using a mold composite resin, the performance and accuracy of the motor are stable even when the temperature rises due to the driving of the motor, and the abrasion resistance is maintained even if the carbide material forming the sliding surface of the vibrating body is driven for a long time. It is sufficient, and the motor performance of the output efficiency also shows a high value.

However, when the sliding surface of the composite resin layer made of a heat-resistant thermoplastic resin filled with the carbon fibers of the moving body is pressed against the hard sliding surface made of the super-hard material of the vibrating body,
For example, when driving at 4 kgcm, 100 rpm as the condition of rated operation, torque swell may be a problem with the temperature rise of the frictional sliding surface, etc.In order to further improve performance accuracy, It was found that there was something to be improved.

In addition, in the continuous operation at the rated torque, there was a torque unevenness of about 5% with respect to the rated torque, and further improvement was demanded.

Further, although there is no problem when the load torque is large, there is a problem that a so-called “squeal” phenomenon based on sliding friction occurs by driving when there is no load or low load.

The object of the present invention made from such a point of view is to have heat resistance and lubricity, and to produce a torque "swell".
It is an object of the present invention to provide a high-efficiency vibration wave drive device with reduced torque and torque unevenness.

Another object of the present invention is to provide a vibration wave drive device having a novel configuration that can eliminate the "squeal" that occurs when driving under no load or low load, which is a problem in vibration wave motors, It is an object of the present invention to provide a vibration wave driving device of the type.

(Means for Solving the Problems) A first configuration for realizing an object of the invention according to the present application includes a vibrating body that generates a vibration wave, and a contact body that presses and contacts the vibrating body. In a vibration wave driving device that relatively moves the vibrating body and the contact body by a vibrating wave, a glass transition point is provided at one contact portion of the vibrating body and the contact body.
The composite resin is formed by filling and mixing at least spherical carbon beads having an average particle diameter of 10 to 30 μm with a thermoplastic resin base material of 140 ° C. or higher.

A second configuration for achieving the object of the invention according to the present application is the above-described first configuration, wherein the composite resin contains the carbon beads in a weight ratio of 5 to 40%.

A third configuration for realizing the object of the invention according to the present application is the above-described first or second configuration, wherein the composite resin is:
It is formed on the contact body.

According to a fourth configuration for realizing the object of the invention according to the present application, in the third configuration described above, the contact body is formed by fixing and integrating a support and a molded body made of the composite resin. .

According to a fifth configuration for realizing the object of the invention according to the present application, in the third configuration described above, the contact body is formed only of the composite resin molded body.

According to a sixth configuration for achieving the object of the invention according to the present application, in the above-described third, fourth, or fifth configuration, the contact portion of the vibrator includes silicon carbide, boron carbide, boron titanium,
The alloy is a nickel-phosphorus-based alloy containing one or more types of boron nitride.

The vibration wave driving device of the present invention has a contact body formed by forming a contact body using the above-described composite resin, or by fixing and integrating the composite resin with a support.

As a method of forming such a composite resin layer and a method of integrating the composite resin layer on a support of a contact body, generally, a slide body of the composite resin material is formed by injection molding or extrusion molding, and this is formed. It can be configured by being fixedly integrated on a support using an adhesive. In addition, the fixing of the sliding body formed of the composite resin material on the support, the glass transition point,
It can be performed using an adhesive at 100 ° C. or higher. Specifically, such an adhesive is a chemical reaction type epoxy adhesive in which heat resistance at 100 ° C. and heat aging are sufficiently considered. Can be exemplified.

In the present invention, the thermoplastic resin used as the base material of the composite resin, that is, a glass transition point of 140 ° C. or higher, generally a glass transition point of 140 ° C. to 275 ° C., preferably a glass transition point of 260 ° C. to 275 ° C. Is used.

Such thermoplastic resins include, for example, polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polyetheretherketone (PEEK), polyethersulfone (PES), polyarylate (PAR),
Examples thereof include polysulfone (PSF) and aromatic polyamide (PA), and more specifically, polyimide (PI) and polyamideimide (PAI).

Filled and blended in the thermoplastic resin as a base material of the composite resin of the present invention, an average particle size of 10 to 30 μ as an anti-wear agent
The m-shaped spherical carbon beads are amorphous and non-oriented.

First, by filling spherical carbon beads, which are wear-resistant fillers, even when, for example, the vibrating body is a sliding part made of a hard material, the properties of the contacting part of the contacting body are always stable, and Secondly, sufficient wear resistance can be exhibited even during long-time driving. Second, the material properties such as the elastic modulus of the contact portion of the contact body are increased, and the motor performance such as output is improved. This is because it can be improved. Third, the heat conductivity of the composite resin can be improved to improve motor performance such as efficiency.

In addition, the composite resin may be further blended with a transition metal powder, if necessary, for the purpose of improving abrasion resistance and improving stability of the sliding portion against temperature change. Specific examples of such transition metal powders include tungsten, molybdenum, chromium, cobalt, titanium, nickel and the like and oxide powders thereof.
% Tungsten powder (20 μm or less), or 15%
% Or less of at least one molybdenum powder (20 μm or less).

(Examples) Hereinafter, the present invention will be described based on examples shown in the drawings.

FIG. 1 is a longitudinal sectional view showing one embodiment of a vibration wave motor as a vibration wave driving device of the present invention.

In this figure, reference numeral 2 denotes an annular vibrating body substrate made of a metal member such as stainless steel, and a thin annular piezoelectric element group 1 is concentrically formed on the back surface thereof with a heat-resistant epoxy resin adhesive. The sliding surface on the front side has a comb-like shape with a large number of grooves cut in the axial direction in the circumferential direction in order to increase the vibration wave width of the progressive vibration wave. Reference numeral 3 denotes a casing made of a metal material having high thermal conductivity, and a first part is provided at the center thereof.
And the vibrating body 2 is fixed with screws 4 concentrically with the axis of the first ball bearing 11.

Reference numeral 10 denotes an output shaft having a flange portion 10c formed in the middle. One end 10a of the output shaft is supported by the inner ring of the first ball bearing 11 so as to be slidable in the axial direction, and the other end 10b
Penetrates an inner ring of a second ball bearing 12 described later and a shaft hole of a spring pressure adjusting nut member 18 described later in an axially slidable and rotatable manner. 15 is the flange 10 of the output shaft 10
A disk-shaped intermediate member fixed to c by a screw 16, and an annular moving body 7 is concentrically externally fitted and fixed to an outer peripheral end of the intermediate member.

The moving body 7 includes an annular support 5 made of a metal having high thermal conductivity such as an aluminum alloy, and a sliding body 6 concentrically adhered to the surface of the support 5 with a heat-resistant epoxy adhesive.
In this example, the sliding body 6 has a thickness of 1 m, for example.
It is formed as a composite resin layer having the composition and configuration described below as an annular body of m. The sliding body 6 comes into contact with the sliding surface of the vibrating body 2.

The moving body 7 is provided in a structure supported by an intermediate member 15 via a rubber elastic sheet member 17 provided on the bottom of the moving body 7, and the movable body 7 is provided with a flange 10c of the output shaft 10 and the second An axial load generated by a coil-shaped compression spring member 14 elastically mounted between the ball bearing 12 and the ball bearing 12 is applied in the axial direction of the support 5 through the sheet member 17, and a sliding surface of the vibrating body 2 is provided. And the sliding body 6 of the moving body 7 is brought into pressure contact.

Reference numeral 8 denotes a housing cover of the vibration wave motor, which is fixed to the housing 3 by screws 9. A second ball bearing 12 is fitted in the bearing fitting hole 8b formed at the center thereof so as to be slidable in the axial direction, and further, on the inner peripheral surface of the bearing fitting hole 8b,
A screw portion 8c is formed, and a spring pressure adjusting nut member 18 is screwed thereto. The spring pressure adjusting nut member 18 is in contact with only the outer ring 12a of the second ball bearing 12, and the inner ring 12b of the second ball bearing 12 is provided so as to be axially slidable and rotatable with respect to the output shaft 10. Then, the insertion rod of a jig (not shown) having, for example, two insertion rods formed at the tip end is inserted into two small holes 18a, 18a formed in the spring pressure adjusting nut member 18, and By turning in the direction, the spring pressure adjusting nut member 18 pushes the second ball bearing 12 in the same direction while screwing in the left direction in the drawing to contract the compression spring member 14 to increase the spring force, and in the opposite direction. When turned, the compression spring member 14 can be expanded to weaken the spring force, whereby the axial load of the output shaft 10 can be adjusted by the deflection of the spring. After adjusting the shaft load of the output shaft 10, it is usual that an adhesive is poured from the small hole 8 a of the housing cover 8 to fix the outer ring 12 a of the second ball bearing 12 to the housing cover 8.

A spacer 13 is disposed between one end of the compression spring member 14 and the second ball bearing 12 so as to abut only on the inner ring 12b of the second ball bearing 12. One end of the compression spring member 14 is , So that the output shaft can rotate smoothly without any trouble. Note that, as the compression spring member 14, a member having a spring constant as small as possible is preferably used in order to reduce the fluctuation of the axial load with respect to the deflection.

As shown in FIG. 2, the piezoelectric element group 1 of the vibrating body 2 includes a driving A piezoelectric element group 1a and a driving B piezoelectric element group 1b, each of which has been subjected to polarization processing as shown in FIG. It consists of two vibration detecting piezoelectric elements 1c and a common electrode 1d for grounding, and the B piezoelectric element group 1b is shifted from the A piezoelectric element group 1a by 1/4 of the wavelength (λ) of the frequency to be excited. Are arranged at different pitches.

By applying frequency voltages having phases different from each other by 90 ° to the A piezoelectric element group 1a and the B piezoelectric element group 1b, a progressive vibration wave is generated on the surface of the vibrating body 2, and the vibrating body 2 is subjected to the vibration as described above. The moving body 7 that has come into pressure contact is driven by friction, and rotates the output shaft 10 via the intermediate member 15.

With respect to the vibration wave motor having the above-described configuration, a plate-like body as a sliding body having the composition shown in the following Table 1 was formed in order to examine the material of the sliding body 6 which is a composite resin layer of the moving body 7 (Experimental Example 1). , 2 and Examples 1 and 2 and Reference Examples 1 to 6), and the flexural modulus thereof was measured as described below.

The sliding body of the example had a glass transition point of 14 as a base material.
The non-fibrous fillers listed in the table are blended with a thermoplastic resin at 0 ° C. or higher as shown below.

Experimental Example 1: A polyetherimide (PEI) "Ultem" (trade name; manufactured by GE) (glass transition point: 215 ° C) was mixed with a graphite powder as a non-fiber reinforced filler at a weight ratio of 30.
%, And a 1 mm plate-shaped body (sliding body) was formed by injection molding.

Experimental Example 2: Polyamideimide (PAI) "TORON"
(Trade name; manufactured by Amoco Co.) (glass transition point: 275 ° C.) was filled and mixed with 30% by weight of graphite powder to obtain a plate-like body similar to that of Experimental Example 1.

Example 1: Polyimide (PI) "New-TPI" (trade name; manufactured by Mitsui Toatsu Chemicals Co., Ltd.) (glass transition point: 260 ° C) was coated with carbon beads (average particle size: 10 µm) as a non-fiber reinforced filler. The mixture was filled and mixed at a weight ratio of 30% to obtain a plate-like body similar to that of Experimental Example 1.

Example 2: In addition to the composition of Example 1, a powder of ethylene tetrafluoride (PTFE) (average particle size 9 μm) was added as a solid lubricant in a weight ratio.
8.5%, Lead oxide powder (average particle size 10μm) 6.0% by weight
The mixture was filled and similarly formed into a plate-like body.

As a reference example, to each heat-resistant thermoplastic resin having a glass transition point of 100 ° C. or higher, in order to improve abrasion resistance, the amount of carbon fiber described in Table 1 was dispersed and filled, and the same plate-like shape as in the example was used. The results were shown in the table. The filling of the carbon fiber is mainly intended to improve the wear resistance. For this purpose, it is desirable that the filling amount is large, but if the filling amount exceeds 30%, injection molding becomes difficult. It is known that the filling of carbon fibers increases the elastic modulus and hardness of the material, and consequently improves the performance of the motor and the like.

Measurement of Flexural Modulus A plate having a thickness of 3.2 mm was measured based on ASTM D792.

As is clear from the above table, the composite resin layer of the present example has, for example, the flexural modulus in Experimental Examples 1 and 2 compared to the plate-like bodies of Reference Examples 1 and 2 using the same thermoplastic resin as a base material. Is small.

It is also understood that Examples 1 and 2 have a smaller flexural modulus than Reference Example 3 using the same thermoplastic resin as a base material.

Example A moving body was prepared by fixing the plate-like body (sliding body) shown in the first table to a support, and using this, a vibration wave motor was manufactured as shown in FIG.

The vibrating body substrate of the vibrating body 2 is an elastic material whose thermal expansion coefficient is close to the thermal expansion coefficient in the plane direction of the piezoelectric element group 1 to which it is fixed, and whose metal has a relatively small thermal expansion coefficient and a small internal loss. Is made of martensitic stainless steel with a diameter of 73 mm and an axial dimension of 7 mm in an annular shape. The sliding surface against which the moving body is in pressure contact is made of eutectoid silicon carbide (SiC). The hard surface (Hv = 600) of the nickel-phosphorus-based alloy (Hv = 600) that had been annealed (about 10%) was annealed to increase the hardness (Hv = 1100).

The moving body is manufactured by forming an annular support having substantially the same dimensions as the vibrating body from a general aluminum alloy, and using the plate-like body (sliding body) shown in the above Table 1 as a composite resin layer by epoxy bonding. It was adhesively fixed using an agent. This sliding body 6
Is about 1mm thick so that one side of a 10mm thick plate material, which is an injection molded product, becomes a sliding surface. After fixing to the support 5, the sliding surface is finely cut (or polished) and finally finished. In addition to the thickness of 1 mm, the carbon fiber was exposed on the sliding surface, so that there was no difference between the initial performance of the motor and the performance over time.

The composite resin layers of Reference Examples 2, 4, and 5 were filled with 5% PTFE to improve lubrication during sliding. In the vibration wave motor of Reference Example, the composite resin layer provided the sliding surface of the moving body. Since the resin layer is filled with carbon fibers, the sliding surface of the vibrating body was made to be a hard surface (Hv ≒ 1200) by spraying the above-mentioned tungsten carbide and cobalt carbide material.

The composite resin layer composed of the above-mentioned sliding body (the above reference examples 1 to 5)
6, and the moving body to which Experimental Examples 1 and 2 and Examples 1 and 2) are fixed,
Incorporated into the large output type vibration wave motor described in FIG.
"Squeal", "output", and "torque unevenness" were measured as follows.

[Measurement of Squeal] The pressure generated by the compression spring member 14 in the vibration wave motor of FIG. 1 was set to 9 kgf, and the squeal at the time of no-load rotation was measured by using FFT. The measurement results are shown as roughly with and without squeal.

[Measurement of output] The magnitude of the output at the rated torque (4 kgcm) was measured using a low-speed torque detector. The measurement results were classified into large, medium, and small according to the magnitude of the output.

[Measurement of Torque Unevenness] The torque unevenness during continuous driving at the rated speed (4 kgcm, 100 rpm) was measured using a low-speed torque detector. The measurement results were classified into medium and small according to the amount of torque fluctuation.

Note that the measurement of the squeal and the output was performed with the vibration amplitude of the vibrating body 2 being a set constant amount in each case.

Further, in the measurement of torque unevenness at the time of rating, the vibration amplitude of the vibrating body 2 was set for each material of the sliding body so as to obtain a rated value.

As is evident from the results in the table above, the rating (4k
gcm, 100 rpm), the swelling of the torque was observed in each of the moving bodies, especially within a few minutes immediately after driving, but the swelling amount was small in Example 2.

Further, the torque unevenness after 2 hours of continuous operation was about 3% in the examples of Examples 1 and 2 in which the non-fiber reinforced filler was filled and mixed, which was smaller than 5% in the reference example.

Looking at the output at the rated time (4 kgcm),
While it was in the range of 5.4 W, the working example was 4.7 to 5.1 W, and there was no significant decrease, and the range was practical.

Further, when the squeal was observed under no load, the squeal phenomenon was observed in all of the sliding bodies of Reference Examples 1 to 6, but the squeal phenomenon was not generated at all in the examples.

(Effects of the Invention) As described above, the present invention includes a vibrating body that generates a vibration wave, and a contact body that comes into pressure contact with the vibrating body, and the vibrating body and the contact body are caused by the vibration wave. In the vibration wave driving device for relatively moving, the vibrating body and the one contact portion of the contact body, the glass transition point of the base material of a thermoplastic resin of 140 ° C. or more, at least an average particle diameter of 10 to 30 μm spherical Since the composite resin formed by filling and blending the carbon beads is formed, it is possible to obtain the effect of improving the swelling and unevenness of the torque at the time of the rated large output.

In addition, since the composite resin of the present invention uses a thermoplastic resin as a base material, an inexpensive injection molding method can be used, and as a filler, spherical carbon beads having an average particle diameter of 10 to 30 μm are used. Since the filler is easily dispersed and non-oriented due to the fluidity of the filler, the wear characteristics can be made uniform at the time of molding, and the mechanical characteristics can also be made uniform.

In addition, an effect is obtained that "squeal" can be avoided when driving under no load or low load.

Further, since a cheap hard surface formed by electroless plating of a nickel-phosphorus-based alloy obtained by eutectoid silicon carbide (SiC) can be used as a contact portion of the vibrating body, a conventional tungsten carbide and cobalt carbide can be used. A high-precision vibration-wave driving device equivalent to the case of using an expensive hard surface sprayed with a material can be formed, and the vibration-wave driving device can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an outline of the configuration of a vibration wave motor to which the present invention is applied, and FIG. 2 is a plan view for explaining an arrangement of a group of piezoelectric elements constituting a vibrating body. 1: Piezoelectric element group, 2: Vibration body 5: Support body, 6: Sliding body 7: Moving body 15: Intermediate member, 17: Elastic sheet member

Claims (6)

(57) [Claims] 1. A vibration wave drive device comprising: a vibrating body that generates a vibration wave; and a contact body that comes into contact with the vibrating body under pressure, wherein the vibration wave relatively moves the vibrating body and the contact body. A composite resin in which a glass transition point of a base material of a thermoplastic resin having a temperature of 140 ° C. or higher is filled with spherical carbon beads having an average particle diameter of at least 10 to 30 μm at one contact portion of the vibrating body and the contact body. The vibration wave driving device characterized by forming. 2. The vibration wave driving device according to claim 1, wherein the composite resin contains the carbon beads in a weight ratio of 5 to 40%. 3. The vibration wave driving device according to claim 1, wherein the composite resin is formed on the contact body. 4. The vibration wave driving device according to claim 3, wherein the contact body is formed by fixing and integrating a support and a molded body made of the composite resin. 5. The vibration wave driving device according to claim 3, wherein the contact body is formed only of the molded body of the composite resin. 6. The method according to claim 3, wherein the contact portion of the vibrator is a nickel-phosphorus-based alloy containing at least one of silicon carbide, boron carbide, boron titanium, and boron nitride. Vibration wave driving device.