JP2000175466A - Oscillatory actuator and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance durability by constituting one of friction materials being employed in an oscillator or the friction sliding part thereof of a laminate film containing an aluminum oxide film and the other of an iron-based material. SOLUTION: An oscillatory actuator is provided, at the outer circumferential part of an oscillator 1, with an oscillator side frictional member 2 and, at the outer circumferential part of a mover 4, with an iron-based moving frictional member 3 of stainless steel, or the like, wherein the oscillator side frictional member 2 is a laminate film containing an aluminum oxide film formed by CVD. Other films are formed beneath the aluminum oxide film, so that the aluminum oxide film is not susceptible to tensile stress and then the surface of mother material is coated before being bonded to the oscillator with an epoxy adhesive. The moving frictional member 3 is made by fitting an iron- based material to a mover 4 by press. According to the structure, the aluminum oxide film is not broken, and high durability can be sustained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration actuator and a vibration actuator for relatively moving a moving body pressed against the vibration body by using a vibration generating element and a vibration body that receives vibration from the element. Related to the device that was used.

[0002]

2. Description of the Related Art Conventionally, an ultrasonic motor has been used as an example of a vibration actuator which relatively moves a moving body pressed against a vibrating body by a vibration generating element and a vibrating body which vibrates in response to vibration from the element. Have been. For example, the ultrasonic motor disclosed in Japanese Patent Application Laid-Open No. 5-252767 has a configuration as shown in FIG. The ultrasonic motor shown in the figure combines the bending vibration generated by the piezoelectric elements 102a and 102c and the expansion and contraction vibration generated by the laminated piezoelectric element 103 to generate an elliptical motion in the friction member 105, and the driven body that comes into contact therewith. The mechanism 106 is moved. The friction member is made of a steel material, and the driven member is made of plate-like ceramic such as alumina.

[0003]

In the above ultrasonic motor, although the friction member 105 always comes into contact with the same location and receives an impact, the contact position of the driven member 106 constantly changes. It seems that ceramics with low resistance and low fatigue strength and ceramics with a large specific wear amount could be used.

However, when this ceramic is applied to a traveling wave type vibration actuator in which a contact portion is repeatedly subjected to impact or friction, for the reason described later, rupture occurs in an alumina-based material, and wear of a ceramic material other than alumina is significantly increased. Therefore, there is a problem that the life of the motor is shortened.

The present invention has been made to solve such problems of the prior art, and has as its object to provide a highly durable vibration actuator and a device using the same. .

[0006]

That is, the present invention provides an electric
A vibrating body that generates vibration in the driving unit by applying an electric signal to the mechanical energy conversion element, and a relative movement between the vibrating body and the frictional sliding unit due to a progressive vibration wave generated by the vibration of the vibrating body. An aluminum oxide film formed by chemical vapor deposition or a laminated film including the aluminum oxide film, wherein one of the friction material used for the frictional sliding portion of the vibration body and the moving body is a vibration actuator composed of The other is a vibration actuator characterized by being made of an iron-based material.

In the laminated film including the aluminum oxide film, it is preferable that a film other than the aluminum oxide film is formed at a position lower than the aluminum oxide film.
In the laminated film including the aluminum oxide film, the aluminum oxide film is preferably formed at a position higher than the film other than the aluminum oxide. The iron-based material is preferably stainless steel having a Vickers hardness of 500 or more.

Further, the present invention is an apparatus characterized in that the above-mentioned vibration actuator is provided as a drive source.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A vibration actuator according to the present invention
A vibrating body that generates vibration in the driving unit by applying an electric signal to the electro-mechanical energy conversion element, and a progressive vibration wave generated by the vibration of the vibrating body through the vibrating body and the friction sliding unit. In a vibration actuator composed of a moving body that moves relatively, one of a friction material used for a friction sliding portion of the vibrating body and the moving body is formed of an aluminum oxide (main composition is alumina) film formed by chemical vapor deposition or It is formed of a laminated film including the aluminum oxide film, and the other is made of an iron-based material.

Usually, a hard material is used as a member requiring abrasion resistance. Taking a cutting tool as an example, high-speed steel, carbide (WC-Co, etc.), cermet (TiC, TiN, etc.), ceramic (alumina, silicon nitride), etc. are used as the material of the cutting tip. In the case of a cutting tool, it is desired that the mating material be cut and removed without causing destruction or wear as much as possible. Normally, cutting is performed in a state where the surroundings are filled with cutting oil, so that the environment is particularly difficult to oxidize.

On the other hand, the friction member of the vibration actuator
Usually used in the atmosphere, lubricating oil or the like is used without intervening between friction members. The reason is that since the vibration actuator is a device that generates a force using a frictional force, there is a strong demand for increasing the frictional force. Therefore, it is common that the friction portion is kept dry. Also, unlike the case of a cutting tool, it is required that both friction members that come into contact with each other have less wear and are not easily broken.

The present inventors have conducted experiments mainly on hard materials such as oxide ceramics, nitride ceramics, carbide ceramics, boride ceramics, and super hard materials. At this time, the mating material is stainless steel or a Ni-based heat-resistant material.

As a result, it turned out to be very interesting.
That is, the wear mode on the hard material side is largely divided into two types.

One is the chemical abrasion found on silicon carbide and the like. Silicon carbide having a Vickers hardness (Hv) of 2000 or more was worn. In addition, it was worn smoothly and almost no wear powder was seen. At this time, the counterpart stainless steel was hardly worn. A smooth surface is always exposed on the sliding surface, and the frictional sliding surface maintains good contact with each other's friction material. The actuator performance (generated force) is stable and desirable. , The life of the actuator is short.

This abrasion causes the silicon wafer to have a smaller hardness than BaCO ₃ , CaCO ₃ or Fe _3.
It can be explained by the principle (mechanochemical phenomenon) that can be polished with O ₄ or the like. That is, it is considered that the surface of silicon carbide changes to SiO ₂ due to frictional heat or the like, and this is removed. This phenomenon is caused by Mo ₂ C, WC, TiB ₂ , TiC, T
It was confirmed also in a substance containing no Si such as iN.

On the other hand, the above-mentioned phenomenon is hardly observed in alumina, and a hole is formed on the surface after a long-time friction drive, and thereafter the fracture proceeds relatively early. The time before this fracture occurred was longer for higher strength alumina. If alumina originally has pores (small density), it will be destroyed early. It was considered that fatigue fracture occurred due to insufficient toughness. As long as this phenomenon can be avoided, alumina has a very small specific wear, and when the mating material is properly selected, it becomes one of the friction materials of the vibration actuator.
It is desirable as one.

According to the above theory, HfC, HfN and the like can be expected as friction materials for the vibration actuator, but they have not been actually confirmed yet. Therefore, when a thin film of aluminum oxide (mainly alumina) was formed on a base material and one of the friction materials was used, and the other was made of an iron-based material such as stainless steel, an experiment was performed. Extended greatly. The reasons were thought to be the following two points.

The chemical vapor deposition method (CV) used in the present invention
The aluminum oxide film formed in D) is denser, has fewer defects such as pores, and has higher strength and toughness than the aluminum oxide material formed by press molding or doctor blade molding. Since the aluminum oxide film was thin, the breaking strength increased due to the effect of bonding with the base material.

However, such a phenomenon that abrasion and destruction hardly occur is also caused by using a heat-resistant alloy containing nickel as a main component, Inconel, as a mating material, even though the hardness is 400 Hv, the Inconel itself is severely worn. A large amount of gray wear powder was generated. In an aluminum alloy which is a wear-resistant material containing 30% of Si, aluminum is transferred to the aluminum oxide side at the moment when the actuator is driven,
Actuator performance has been significantly reduced. In addition, beryllium copper, which is well known as a wear-resistant material, has been severely deformed and has been continuously required as a friction member. A friction material for a vibration actuator is different from a cutting tool, and it is required that both friction materials are hardly worn or broken.

Compared with the above materials, when the iron-based material containing iron as a main component (content of 50 wt% or more) was used as the aluminum oxide film in the present invention, the wear resistance was remarkably excellent. The reason is considered to be that the magnetite (Fe ₃ O ₄ ) film, which is an oxide film unique to iron, formed on the surface prevented the adhesive wear with aluminum oxide.

Next, a feature of the present invention is that one of the friction materials is formed of a laminated film including an aluminum oxide film formed by chemical vapor deposition, and a film other than the aluminum oxide is formed below the aluminum oxide film (closer to the base material). (Place). The base material is preferably a hard material such as a super hard material and has a large deformation resistance, but is expensive. Even so, by providing a film other than aluminum oxide in the lower layer, even if the base material is not so hard and inexpensive, the base material collapses during friction sliding, and it cannot withstand the deformation and aluminum oxide is broken. No more. The film formed under this layer is TiC,
A hard film such as TiN or TiCN is desirable.

Further, a feature of the present invention is that it is formed of a laminated film including an aluminum oxide film formed by chemical vapor deposition, and a film other than the aluminum oxide is formed on the aluminum oxide film. Thus, since the aluminum oxide film is bonded and bound by a film other than aluminum oxide, a tensile stress that causes aluminum oxide destruction is less likely to be applied to the aluminum oxide itself.
The film other than the aluminum oxide is TiC, TiC.
It is desirable to be formed of a material having higher fracture toughness than aluminum oxide, such as N or TiCN.

The present invention is also characterized in that stainless steel having a Vickers hardness of 500 or more is used as the other friction material. Stainless steel originally has a chromium oxide (passive film) near the surface, and is easily worn by red rust (Fe ₂
It was considered that O ₃ ) was hardly formed on the surface, so that it was hard to wear. In addition, since the hardness is 500 Hv or more, aluminum oxide (Vickers hardness of 150
(0 or more), the abrasive wear is difficult to progress even if the surface roughness is somewhat large.

The vibration actuator of the present invention can be used for, for example, a vibration wave motor, a paper feeder, a linear motor, and the like. Further, the vibration actuator of the present invention can be used for various devices as a drive source. Specific examples of the equipment include optical equipment such as a camera, office equipment such as a printer and a copying machine, and automobile-related equipment such as a power window and an active suspension.

[0025]

EXAMPLES The present invention will be specifically described below with reference to examples.

Embodiment 1 FIG. 1 is a schematic view showing an embodiment of the vibration actuator of the present invention. FIG. 1 shows the appearance of a rod-shaped vibration motor as an example of a vibration actuator. Details such as the driving principle of this rod-shaped vibration motor are described in JP-A-5-212785. In the figure, a vibrating body-side friction member 2 is provided on an outer peripheral portion of a vibrating body 1, and a moving body-side friction member 3 made of an iron-based friction member such as stainless steel is provided on an outer peripheral portion of a moving body 4.

As the vibrating body-side friction member 2, the base material and the coating film of the types shown in Tables 1 and 2 were used.

[0028]

[Table 1]

[0029]

[Table 2]

(Note) TiC indicates titanium carbide, and TiN indicates titanium nitride.

FIG. 2 is a schematic view showing a friction contact portion of the vibration motor of FIG. 1, FIG. 2 (a) is an enlarged sectional view of the friction contact portion, and FIGS. It is an enlarged view near the friction sliding surface of the vibration body side friction member.

FIG. 2 (b) shows an example in which three layers of various materials are coated on the surface of the vibrating body-side friction member on the base material 11, but the base material is used as a friction sliding material without coating. Some have been tested. In addition, there is also a coating in which only one layer or two layers are covered as shown in FIG.

As a base material, extremely high purity of 99.9%
Other than alumina, carbide and stainless steel JIS SUS32
1 was prepared. SUS321 was adopted because titanium nitride, titanium carbide, and titanium carbonitride have excellent adhesiveness when deposited on the film by vapor deposition. Each base material was subjected to surface grinding with a grindstone and then polished with diamond abrasive grains in order to improve the flatness corresponding to the friction sliding surface in advance. The base material was held at 1000 ° C. for 30 minutes in vacuum before surface grinding, cooled to 500 ° C. at a rate of 20 ° C. per minute, and then cooled with nitrogen gas. By performing such annealing treatment, the internal stress of the base material was removed. This is to prevent the base material from being deformed in the high temperature chemical vapor deposition process.

Thereafter, each material was coated on the surface of the base material by each manufacturing method to obtain a vibrating body-side friction member. Next, the vibrating body-side friction member was fixed to the vibrating body 1 with an epoxy adhesive.

On the other hand, as the moving body side friction member 3, Table 3
Was prepared by press working and fitted and bonded to the moving body 4. In order to maintain good actuator performance, it is necessary to reduce the flatness and surface roughness of the friction sliding surface. Therefore, the frictional sliding surface on the moving body side was subjected to surface grinding with a grindstone and then polished with diamond abrasive grains. Since the movable body 4 is made of a ferromagnetic material (iron, 13 chrome stainless steel, 18 chrome stainless steel, or the like) that is attracted to a magnet, it can be easily fixed to a grinding machine at the time of surface grinding. Further, by reducing the particle size of the surface grinding wheel, the diamond polishing in the subsequent process can be omitted.

[0036]

[Table 3] The reason for preparing four types of the moving body side friction members is as follows.
This is mainly for examining the effect of hardness. The friction materials of Tables 1 to 3 were combined as shown in Table 4, and the superiority of each combination of the friction materials was evaluated through the test method described below. The test was performed using the rod-shaped vibration motor shown in FIG. The surface pressure applied perpendicular to the friction sliding surface was 4 MPa. The rotation angle of the moving body is 120 degrees per 25 msec (corresponding to 800 rpm),
Reciprocating reversal every 120 degrees (２５ rotation) (25m when reversing)
Per second) and a durability test was performed. The total number of reversals is 450
The operation was repeated 10,000 times (sliding distance: 87 km).

After performing the durability test under the above conditions, the wear amount of the friction member on the vibrating body side and the friction member on the moving body side were measured, and the surface properties were observed by a scanning electron microscope.

The evaluation was based on the following criteria. × indicates that the friction member on the vibrating body side or the friction member on the moving body side has worn out by 10 μm or more, Δ indicates that the friction member on the moving body side has a wear of 10 μm or less, and that the friction member on the vibrating body side has 1 to 10 μm. In the case where the wear of the friction member was 10 μm or less and the wear of the friction member on the vibrator side was 3 μm or less, it was evaluated as ○.

Table 4 shows the above results. The reason why a severe numerical value is required for the amount of wear of the friction member on the vibrating body side is that a rut is formed and the performance of the motor tends to decrease as the rut becomes deep.

[0040]

[Table 4]

(Note) * 1 denotes the friction material used for the vibrating body. Is shown. * 2 is the friction material used for the moving object.
o. Is shown. Test No. The asterisk indicates an example.

Test No. 1 used 99.9% alumina. This alumina was used as a raw material in which primary particles were sized to about 0.3 μm, formed into a sheet shape by a doctor blade method, and then fired. The fired plate was punched into a ring of a predetermined size by laser processing, and was subjected to a test. In the case of this alumina ring, after bonding to the elastic member of the vibrating body 1, the friction sliding surface was lapped on a copper plate using diamond particles having an average diameter of 3 μm. The surface roughness obtained at that time was Ra 0.1 μm or less.

The alumina was very dense without any pores on the surface. The hardness was determined by forming an indentation on the alumina surface with an indenter of a Vickers hardness tester under a predetermined load, and observing and measuring the indentation with a scanning electron microscope. Test No. In the case of 1 to 10, a heat-treated martensitic stainless steel SUS420j2 was used as a friction material on the moving body side. The hardness at this time is 680 Hv, which is considered to be the maximum hardness obtained with this material.

Test No. The predetermined durability test of No. 1 was completed, and the wear amount of each friction member was measured. As a result, the amount of wear on the alumina side was only 0.2 μm, but holes were formed on the sliding surface. This hole was considered to have been caused by the fracture of the alumina. The alumina used has a flexural strength of 600 MPa, which is the highest level of pure alumina. As long as pure alumina is used, it is not possible to prevent the generation of holes caused by the above-mentioned fracture by the current motor drive. Conditions seemed difficult. Further, the stainless steel as the mating material was worn by 15 μm.

When examined at about the middle of the endurance test,
No holes were formed on the sliding surface of the alumina, and the wear on the stainless steel side hardly progressed. This was thought to be due to the fact that the fracture occurred suddenly at some stage and severely abraded the stainless steel due to the alumina powder generated by this hole or the broken and roughened surface. In other words, in the case of aluminum, delaying the destructive phenomenon of the formation of holes leads to a longer life of the motor.

Test No. In Nos. 2 and 3, TiC and TiN were used as friction materials on the vibrator side, respectively. 9 for base material
Carbide of 5% WC was used. The cemented carbide was cut out of a sintered pipe-shaped material into a predetermined ring shape by wire electrode processing. Next, after heating to 1000 ° C. in a vacuum and removing the internal stress by removing the command, both end faces were subjected to surface grinding and lapping to obtain a base material. The base material was a test no. 2
-8 and No. 1 Test N, provided for 14-16
o. 2 is a 5 μm thick Ti on the surface of the base material by a chemical vapor deposition method.
A C film was deposited. Test No. In No. 3, a thickness of 5 μm was also deposited by physical vapor deposition. As a result of the durability test, Ti
The C film was completely worn, and even the superhard of the base material was worn by about 3 μm. On the other hand, the TiN film was settled down with a wear amount of about 2 μm. The phenomenon in which TiN, TiC and carbide having a Vickers hardness of 2000 to 3000 are worn by much smaller stainless steel can be explained by the mechanochemical effect. The wear of the stainless steel was slight.

Test No. In Nos. 4 and 6, alumina was sprayed on the superhard surface, and the surface was finished by lapping so that the thickness of the sprayed film became 5 to 20 μm. In all of the results, the alumina film was broken and a large amount of red-brown abrasion powder adhered to the periphery of the sliding surface. Qualitative analysis of this reddish brown powder detected iron, chromium and aluminum. In other words, abrasion powder of iron and crushed powder of alumina are mixed. The amount of wear on the stainless steel side was large, and this combination of friction members did not provide very good results.

Test No. When the frictional sliding portion and its vicinity were observed with an electron microscope after durability at 7, the sliding surface on the aluminum oxide (composition was mainly alumina) side was slightly rougher than the non-sliding surface. The stainless steel itself was extremely small at 0.1 μm, and the mating stainless steel was only worn at 2 μm.

Test No. In Test No. 8, the TiN formed on the outermost surface (first layer) was almost completely worn out on the sliding surface, but the exposed alumina surface was not covered with Test No. It was smoother than at 7. When the sliding surface was qualitatively analyzed, Ti was detected in addition to Al. Since the TiN was worn according to the shape (convex) of the sliding surface of the mating stainless steel friction material, the TiN was worn in a rounded concave shape. Therefore, it is considered that the frictional sliding surface was substantially widened and the applied surface pressure was reduced, thereby preventing the alumina surface from being damaged.
2 (b) and 2 (c) show the form of wear in a cross-sectional view. As shown in FIG. 2 (c), when aluminum oxide with relatively little wear is arranged on the outermost surface (test No. .
In 7), the other stainless steel comes into contact with only a part of the sliding surface at the same time. That is, stress concentration occurs. On the other hand, in the case of FIG. 1B (test No. 8), since the film which is relatively easily worn is on the outermost surface, the film is worn first according to the shape of the contact part of the other party, and the second layer When the aluminum oxide film is exposed, the progress of wear is suddenly slowed down. By this time, the mating member has a convex roundness.

The following three reasons can be considered as the reason why the sliding portion of the other stainless steel becomes convex, but it is considered that it is mainly due to deformation rather than wear. Because it is already very early in its endurance.

Since the vibration direction of the vibrator is not perpendicular to the sliding surface but inclined, a high stress is applied near the ridgeline of the stainless steel. When flat surfaces are pressed against each other, the stress applied to the surfaces is not uniform, but increases at the ridgeline. The friction surface of the stainless steel member
At the moment of vibrating contact with the vibrator-side friction member, the stainless steel member is elastically deformed and twisted, and the surface pressure near the ridge increases.

Although not shown in this test, test No. 7 and test no. When the surface pressure on the friction sliding surface was doubled (8 MPa) with the combination of the respective friction materials of No. 8 and the experiment was conducted, the friction member having the outermost surface layer of aluminum oxide was found to be damaged by the aluminum oxide. Reached. On the other hand, those coated with TiN on the outermost surface did not lead to destruction. In other words, if the durability test is performed under more severe conditions, the outermost surface provided with TiN and covered with the lower aluminum oxide film is less likely to cause local stress concentration on the aluminum oxide as described above. It is considered that the effect that the TiN film of the moving part reinforced the lower aluminum oxide film appeared, and the TiN film did not break.

Test No. 9 and no. In the case of using a base material of stainless steel, which is inexpensive compared with carbide, Ti
In the sample provided with the C film (No. 10), the aluminum oxide coated thereon did not fall and did not break. If a material having a large deformation resistance, such as TiC, TiN, or TiCN, is arranged in the lowermost layer, a soft material can be used as the base material. At this time, the base material is relatively soft stainless steel used in the examples or JIS SUS440C, JIS
Tool steel such as stainless steel other bearing steel (JIS SUj2) hardened by heat treatment such as SUS420j2
IS SKD11, JIS SKH51, SK3, etc.).

Test No. Nos. 11 to 13 and No. 14 ~
No. 16 was carried out to examine the effect of the hardness of the iron-based friction member of the mating material.

As a result, it was found that the harder the iron-based friction member, the smaller the amount of wear itself. Those with a large amount of wear have red-brown powder scattered near the friction sliding surface. This is iron oxidized (mainly Fe ₂ O ₃ ). In the case of soft iron, abrasive wear is promoted. As long as the frictional sliding surface of the mating alumina or the like is smooth, even a soft iron-based member wears little, but when the alumina surface becomes rough, the harder (500 Hv or more) itself wears less as the alumina surface becomes rougher. desirable.

Embodiment 2 FIGS. 3 to 5 show a ring-shaped vibration wave motor which is an example of a vibration actuator according to a second embodiment of the present invention. The driving principle of this vibration wave motor is disclosed in
It is already known, for example, from JP-A-9-201685.

In FIGS. 3 to 5, reference numeral 1 denotes a vibrating body, on which a number of protrusions are formed, and a friction member 2 on the vibrating body side is joined to the tip of the protrusion. Also, on the friction surface, No. Eight combinations of films are formed. However, in this case, the base material may be the vibrator 1 itself.
Since the film is formed by vapor deposition, the film is relatively easily formed even in a complicated shape. On the other hand, 4 is a moving body. This friction sliding member is also quenched and tempered according to JIS SUS42.
0j2. The above configuration is the same as in the first embodiment. Of course, the above arrangement of the friction material may be reversed on the vibrating body side and the moving body side. Reference numeral 5 denotes an electromechanical energy conversion element joined to the vibrating body 1, which receives an alternating voltage and
A progressive vibration wave is generated at the projections of.

The moving body side friction member 3 is in pressure contact with the vibrating body 1 by receiving a pressing force of a pressing means (not shown). As a result, the moving body rotates by receiving the friction driving force, but the movement is a relative movement caused by the frictional force, and when the vibration body is fixed, the moving body rotates, and conversely, the moving body rotates. If fixed, the vibrator rotates.

In this type of motor, the friction member on the moving body side comes into contact with the radial ridge of the projection, so that it is desirable to arrange a friction material having higher destructive toughness than in the first embodiment. In the present embodiment, TiN, which has higher fracture toughness than aluminum oxide, is formed on the outermost surface of the protrusion.
A film is provided, and the actual frictional contact state can be determined by the wear state of the film.

That is, the ridge line of the projection is rounded after the durability test. The ridge line is initially in strong contact with the moving body, and becomes rounder as the durability test progresses, resulting in stress relaxation. Therefore, even when a part of the aluminum oxide film is exposed when the TiN film is worn, high stress is not applied to the aluminum oxide film.

FIG. 6 is a view for explaining the above phenomenon. FIG. 6A is an enlarged view of a projection of the vibrating body 1 in which a friction member is joined to the vibrating body. FIG. 6B is a view showing that a friction film is formed directly on the vibrating body.

FIG. 7 is a schematic diagram of a device using the vibration wave motor shown in FIG. 1 as a driving source. 23 is a large gear 23
a large gear 23a meshes with the gear 10 of the vibration wave motor (vibration actuator) 27 side. Reference numeral 24 denotes a driven member, for example, a lens barrel.
The small gear 23 of the gear 23 is attached to the gear 24a provided on the outer peripheral portion.
b are engaged and rotated by the driving force of the motor. On the other hand, an encoder slit plate 25 is attached to the gear 23,
The rotation of the gear 23 is detected by the photocoupler 26,
For example, rotation and stop of the motor are controlled for autofocus.

[0063]

As described above, according to the present invention, as a friction material for a vibration actuator, at least one film of aluminum oxide such as alumina is formed by a chemical vapor deposition method, and the other is a ferrous material. By using this, a highly durable vibration actuator could be obtained. In addition, if a film other than aluminum oxide is formed closer to the base material than the aluminum oxide film, even if the base material has a small deformation resistance, the aluminum oxide film is not broken and has high durability. Can maintain the nature. If another type of film is formed above the aluminum oxide film (close to the surface), a vibration actuator having higher durability can be obtained.

Further, when an iron-based material having a Vickers hardness of 500 or more is used as the mating friction material, the wear of itself is reduced, and when the wear of the mating friction material determines the life of the vibration actuator, The service life can be further extended.

Further, the present invention can provide a vibration wave motor comprising a vibration actuator having the above-mentioned excellent frictional characteristics and a device using the same.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of a vibration actuator of the present invention.

FIG. 2 is a schematic view showing a friction contact portion of the vibration motor of FIG.

FIG. 3 is a schematic view showing a part of a ring-shaped vibration wave motor which is an example of a vibration actuator according to a second embodiment of the present invention.

FIG. 4 is a schematic view showing a part of a ring-shaped vibration wave motor which is an example of a vibration actuator according to a second embodiment of the present invention.

FIG. 5 is a schematic view showing a part of a ring-shaped vibration wave motor which is an example of a vibration actuator according to a second embodiment of the present invention.

FIG. 6 is an enlarged view showing a protrusion.

7 is a schematic diagram of a device using the vibration actuator shown in FIG. 1 as a driving source.

FIG. 8 is a schematic view showing a conventional ultrasonic motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vibration body 2 Vibration body side friction member 11 Base material 21 First layer (Coating layer) 22 Second layer (Coating layer) 23 Third layer (Coating layer) 3 Moving body side friction member 4 Moving body 5 Electro-mechanical energy conversion element Reference Signs List 6 electrode plate 7 elastic member 8 bolt 9 pressure spring 10 gear 102 elastic body 102a, 102c piezoelectric element 103 laminated piezoelectric element 104 head member 105 friction member 106 driven body

Claims (5)

[Claims] A vibrating body for generating a vibration in a driving section by applying an electric signal to an electro-mechanical energy conversion element; and a frictional sliding contact between the vibrating body and a progressive vibration wave generated by the vibration of the vibrating body. A vibrating actuator comprising a moving body that relatively moves through a moving part, wherein one of the friction material used for the friction sliding part of the vibrating body and the moving body is an aluminum oxide film formed by chemical vapor deposition or the aluminum oxide film. A vibration actuator formed of a laminated film including an aluminum oxide film, and the other made of an iron-based material. 2. The vibration actuator according to claim 1, wherein in the laminated film including the aluminum oxide film, a film other than the aluminum oxide film is formed at a position lower than the aluminum oxide film. 3. The vibration actuator according to claim 1, wherein in the laminated film including the aluminum oxide film, the aluminum oxide film is formed at a position above the film other than the aluminum oxide. 4. The iron-based material has a Vickers hardness of 500.
The vibration actuator according to claim 1, wherein the vibration actuator is made of stainless steel. 5. An apparatus provided with the vibration actuator according to claim 1 as a drive source.