JP2006271034A - Oscillatory wave motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oscillatory wave motor that is reduced in the wear of a friction contact face, stabilized in drive performance, eliminated in the occurrence of noise, and can achieve a long service life. <P>SOLUTION: In the oscillatory wave motor 10 comprising an elastic body 12 that generates vibration by the excitation of a piezoelectric body 11, and a moving body 13 that pressure-contacts with the elastic body 12 and is driven by the vibration, at least either of parts including the friction contact faces of the elastic body 12 and the moving body 13 is an electroless Ni-P/PTFE composite-plating membrane layer 17, and the other is an anode oxide coated membrane layer 18. Both the electroless Ni-P/PTFE composite-plating membrane layer 17 and the membrane layer 18 are not less than 250 in Vickers hardness, and the difference of the Vickers hardness between the two layers is not more than 100. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vibration wave motor that generates vibration waves in a vibrator using an electromechanical transducer and frictionally drives a relative motion member using the vibration waves, and more particularly to a frictional contact surface between the vibrator and the relative motion member. The present invention relates to an improved vibration wave motor.

  2. Description of the Related Art Conventionally, a vibration wave motor that generates a vibration wave in a vibrator using an electromechanical transducer and drives a relative motion member using the vibration wave is known. In this type of vibration wave motor, the vibrator and the relative motion member are in frictional contact, and vibration waves generated in the vibrator, for example, ultrasonic vibrations are transmitted to the relative motion member, and the relative motion member is friction driven. Is done. Accordingly, since the vibrator needs to efficiently transmit the applied ultrasonic vibration to the relative motion member, a highly elastic material, for example, an iron-based or stainless-based metal material is used.

When such a conventional vibration wave motor is friction-driven for a long time, the frictional contact surface between the vibrator and the relative motion member deteriorates and wears. As a result, the vibration wave motor generates wear powder on the frictional contact surface, and the driving performance becomes unstable, and eventually, there is a possibility that it cannot be driven. Therefore, the conventional vibration wave motor has a problem that it is difficult to continue stable driving in a long-term continuous durability test.
Although this friction contact surface can reduce wear by using lubricating oil or the like, since the motor torque (friction coefficient × proportional to pressurizing force) becomes small, non-hydrodynamic lubrication, so-called Boundary lubrication must be the main.

In order to reduce wear of the friction contact surface, for example, in Patent Document 1, one of the friction contact surfaces is made of hard anodized, and the other is electroless nickel containing at least one of silicon carbide, boron carbide, boron titanium, and boron nitride. Techniques for alloying are disclosed. Patent Document 2 discloses a technique using stainless steel (SUS420 J2) having a Vickers hardness of 400 or more and subjected to quenching and tempering treatment on the frictional contact surface of the vibrating body.
However, although both methods reduce wear, there is a problem that unpleasant noise is generated during friction driving. In addition, the technique disclosed in Patent Document 2 has a problem that the production cost is increased because the number of processing steps increases.
Japanese Patent No. 2578903 JP 3-36970

In order to reduce noise generated during friction driving, it is conceivable to add a fluororesin having a small friction coefficient and excellent self-lubricating property to any one of the friction contact surfaces.
For example, abnormal noise can be reduced by using composite plating of fluororesin and nickel-phosphorus (Ni-P) on one of the friction drive surfaces. However, depending on the amount of the fluororesin added, the fluororesin may fall off the Ni-P plating due to an attack from the friction contact surface on the other side, or irregularities on the order of μm to sub-μm due to the holes from which the fluororesin has escaped. It works like a blade to attack the frictional contact surface on the other side, and the rupture strength of the plating itself decreases as the fluororesin escapes, so the amount of wear increases even if noise can be reduced End up.
Therefore, it has been difficult to reduce both wear and noise at the same time.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vibration wave motor that is free from abnormal noise, can reduce wear on the frictional contact surface, stabilize drive performance, and extend its life.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to the Example of this invention is attached | subjected and demonstrated, it is not limited to this.
According to the first aspect of the present invention, the vibrator (11, 12) that generates vibration in the elastic body (12) by the excitation of the electromechanical transducer (11) is brought into pressure contact with the vibrator, and by the vibration, In a vibration wave motor comprising a relative motion member (13) that performs relative motion with the vibrator, at least one of the portions including the frictional contact surface between the vibrator and the relative motion member is formed of a transition metal and self A composite coating layer (17) formed of a lubricating substance, and the other is a porous oxide coating layer (18). Both the composite coating layer and the porous oxide coating layer have a Vickers hardness of 250 or more. In addition, the vibration wave motor is characterized in that the difference in Vickers hardness is 100 or less.
The invention according to claim 2 is the vibration wave motor according to claim 1, wherein the composite coating layer (17) is a composite plating layer formed of electroless nickel-phosphorus and a fluororesin. This is a vibration wave motor.
According to a third aspect of the present invention, in the vibration wave motor according to the first or second aspect, the porous oxide film layer (18) is formed by subjecting an aluminum or aluminum alloy surface to an anodizing treatment and an oxide film on the surface. The vibration wave motor is characterized in that it is a layer in which is formed.

According to the present invention, the following effects can be obtained.
(1) At least one of the portions including the frictional contact surface between the vibrator and the relative motion member is a composite coating layer formed of a transition metal and a self-lubricating substance, and the other is a porous oxide coating layer. The composite coating layer and the porous oxide coating layer both have a Vickers hardness of 250 or more and a difference in Vickers hardness of 100 or less, so that the frictional contact surface is reduced and the drive is stable for a long time. And the life of the vibration wave motor can be extended.
(2) The composite coating layer is a composite plating layer formed of electroless nickel-phosphorus and fluororesin, and since it contains a fluororesin having a small friction coefficient and self-lubricity, it can reduce wear on the frictional contact surface. The noise during sliding can be reduced.
(3) The porous oxide film layer is a layer in which the surface of an aluminum or aluminum alloy is anodized and an oxide film is formed on the surface thereof. Can be used.

  The object of the present invention is to provide a vibration wave motor that reduces frictional contact surface wear, stabilizes drive performance, does not generate abnormal noise, and can prolong the service life. At least one of the portions including the frictional contact surface is an electroless Ni-P / PTFE composite plating film layer, the other is an alumite film layer, and the electroless Ni-P / PTFE composite plating film layer and the alumite film layer are Both are realized by having a Vickers hardness of 250 or more and a difference in Vickers hardness of 100 or less.

Hereinafter, embodiments of a vibration wave motor according to the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, an ultrasonic motor using an ultrasonic vibration region will be described as an example of the vibration wave motor.
FIG. 1 is a diagram showing an embodiment of a vibration wave motor according to the present invention.
The vibration wave motor 10 is an actuator that includes a piezoelectric body 11 and an elastic body 12 that constitute a vibrator, and this vibrator pressurizes and contacts a moving body 13.

The piezoelectric body 11 is one of electromechanical conversion elements and is excited by supplying a drive signal. For example, a support body such as a lens barrel of a camera is provided via a vibration absorber 15 such as felt. 16 is fixed.
The elastic body 12 is bonded to the piezoelectric body 11 with a conductive adhesive or the like, and generates a progressive vibration wave by excitation of the piezoelectric body 11. The elastic body 12 is made of a metal material, for example, an iron alloy such as brass, a stainless material, or an invar material.
The moving body 13 is a relative motion member that is brought into pressure contact with the elastic body 12 and frictionally driven by a progressive vibration wave.
The flexible printed board 14 is for supplying a driving signal to the piezoelectric body 11 and is electrically connected to a predetermined electrode portion of the piezoelectric body 11.

FIG. 2 is a sectional view showing in detail the frictional contact surface between the elastic body and the moving body in the embodiment of the vibration wave motor according to the present invention.
The elastic body 12 is provided with an electroless Ni—P / PTFE composite plating film layer 17 on a frictional contact surface with the moving body 13.
The moving body 13 is made of an aluminum alloy material, and an alumite film layer 18 that is a porous oxide film layer is provided on the frictional contact surface with the elastic body 12.
Therefore, the frictional contact surface between the elastic body 12 (vibrator) and the moving body 13 is in a form in which the electroless Ni-P / PTFE composite plating film layer 17 and the alumite film layer 18 are in contact with each other.

Next, an embodiment of the vibration wave motor according to the present invention will be described in more detail.
The elastic body 12 is made of stainless steel (SUS304), and the electroless Ni-P / PTFE composite plating film layer 17 formed on the frictional contact surface with the moving body 13 is made of electroless nickel-phosphorus and fluororesin. A composite coating layer. The electroless Ni—P / PTFE composite plating film layer 17 is preferably formed to a thickness of 40 μm or less. The piezoelectric body 11 is adhered to the bottom surface (surface opposite to the vibrating body 13 side) of the elastic body 12 by an epoxy adhesive or the like.

  On the other hand, the moving body 13 is formed of an aluminum alloy (A6063), and the alumite coating layer 18 is a layer formed by anodizing the surface of the moving body 13. Specifically, the alumite film layer 18 is obtained by anodizing the surface of aluminum or an aluminum alloy using a sulfuric acid-based aqueous solution as an electrolyte and forming an oxide film layer of alumite sulfate on the surface. The alumite film layer 18 is preferably formed to a thickness of 80 μm or less.

  The PTFE content and Vickers hardness of the electroless Ni-P / PTFE composite plating film layer 17 as described above, the Vickers hardness of the anodized film layer 18, the electroless Ni-P / PTFE composite plating film layer 17 and the anodized film layer 18 Several vibration wave motors with different Vickers hardness differences were prepared and actually driven under the same conditions, and the initial motor performance and wear amount were examined.

FIG. 3 is a table showing driving results of the vibration wave motors of the examples and comparative examples according to the present invention.
The actually driven vibration wave motors of the examples and comparative examples have substantially the same shape, but as shown in FIG. 3, the electroless Ni-P / PTFE composite plating film layer 17 and the alumite film layer 18 Vickers hardness and the difference in Vickers hardness are different.
In the vibration wave motors of Examples 1 to 6 according to the present invention, the Vickers hardness of the electroless Ni-P / PTFE composite plating film layer 17 and the alumite film layer 18 is 250 or more as shown in FIG. And the difference of the Vickers hardness is 100 or less.
In the vibration wave motors of Comparative Examples 1 to 3, both the electroless Ni-P / PTFE composite plating film layer 17 and the alumite film layer 18 have a Vickers hardness of 250 or more. However, the electroless Ni-P / PTFE composite plating film layer 17 has been heat-cured, and the difference in Vickers hardness between the electroless Ni-P / PTFE composite plating film layer 17 and the alumite film layer 18 is: Over 100.
In the vibration wave motors of Comparative Example 4 and Comparative Example 5, the difference in Vickers hardness between the electroless Ni-P / PTFE composite plating film layer 17 and the alumite film layer 18 is 100 or less, as shown in FIG. However, the vibration wave motor of Comparative Example 4 has a Vickers hardness of the electroless Ni—P / PTFE composite plating film layer 17 of less than 250, and the vibration wave motor of Comparative Example 5 has a Vickers hardness of the anodized film layer 18 of 250. Is less than.

  The initial performance of the motor means abnormal noise, input power, startability at low speed, etc., low noise during driving, and motor efficiency (output from motor / input to motor) at 15% or more at rated output In addition, when the value obtained by dividing the rated speed by the minimum speed is 20 or more, the initial performance is assumed to be good, and is indicated by ◯ in the table.

  As for durability, the wear thickness (thickness reduced by wear) of the frictional contact surface between the electroless Ni-P / PTFE composite plating film layer 17 and the alumite film layer 18 per 10,000 revolutions is less than 0.5 μm. In the table, the durability is good and indicated by ○ in the table. In addition, when the wear thickness is 0.5 to 1.0 μm, the durability is slightly bad, indicated by Δ in the table, and when the wear thickness is 1.0 μm or more, the durability is bad, Indicated in the table with x.

As shown in FIG. 3, the initial performance of the motor was good in both the examples and the comparative examples.
Regarding the durability, the vibration wave motors of Examples 1 to 6 were good.
However, as shown in FIG. 3, the vibration wave motors from Comparative Example 1 to Comparative Example 3 in which the difference in Vickers hardness between the electroless Ni-P / PTFE composite plating film layer 17 and the alumite film layer 18 exceeds 100 are as follows: The result that durability was inferior was obtained.
In addition, the vibration wave motors of Comparative Example 4 and Comparative Example 5 in which either one of the electroless Ni-P / PTFE composite plating film layer 17 or the alumite film layer 18 has a Vickers hardness of less than 250 are also inferior in durability. was gotten.

Furthermore, although not shown in the driving results shown in FIG. 3, when the film thickness exceeds 80 μm, the anodized film layer 18 has a sparsely generated portion that appears in the manufacturing process, and the anodized film The wear of layer 18 and electroless Ni-P / PTFE composite plating film layer 17 was significantly increased.
Further, in the electroless Ni-P / PTFE composite plating film layer 17, when the film thickness exceeds 40 μm, a portion where PTFE generated in the manufacturing process is segregated appears remarkably, and the anodized film layer 18 and the electroless film layer 18 are electroless. The wear of the Ni-P / PTFE composite plating film layer 17 was remarkably increased.
Furthermore, when the Vickers hardness of the alumite coating layer 18 or the electroless Ni—P / PTFE composite plating coating layer 17 was less than 250, the generation of wear powder was remarkably increased.

Therefore, from the above results, both the Vickers hardness of the electroless Ni-P / PTFE composite plating film layer 17 and the alumite layer 18 are 250 or more, and the difference in the Vickers hardness is 100 or less, as described above When the vibration wave motor 10 having the configuration was driven, the following advantageous effects were obtained as compared with the conventional vibration wave motor.
(1) The amount of wear on the friction contact surface is extremely small, and stable friction drive can be performed for a long time.
(2) The driving torque generated by the pressurization of the elastic body 12 and the moving body 13 is large.
(3) Abnormal noise generated during friction drive is small.
(4) By long-time driving, there is little deterioration with time and stable driving can be obtained.

Further, since aluminum and nickel have a low mutual solubility, they are less likely to cause seizure even when driven by friction. Furthermore, nickel is a transition metal, and a combination using a transition metal can be expected to be a severe mild transition.
This severe mild transition is generally called a familiar phenomenon. In this combination, intense wear (severe wear) does not progress linearly, but after rubbing a certain distance, a mixed layer of both friction materials (aluminum and nickel) and its oxide layer on the friction contact surface And it becomes a surface protective layer, and transition to mild wear occurs, so that stable driving can be performed for a long time.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
(1) In the present embodiment, an example in which the electroless Ni-P / PTFE composite plating film layer 17 is provided on the elastic body 12 side and the alumite film layer 18 is provided on the moving body 13 side is shown. On the contrary, the elastic body 12 is made of aluminum or an aluminum alloy, an alumite film layer 18 is provided on the movable body 13 side, and the electroless Ni-P / PTFE is disposed on the elastic body side 12 side of the movable body 13. A composite plating film layer 17 may be provided.

(2) In the present embodiment, an example of using an A6063 material as an aluminum alloy is shown, but not limited thereto, other aluminum alloys (A6061, A5056, A5052, A2024, A7075, ADC12, AC8A, etc.) or aluminum It may be used.
Moreover, although the example in which the alumite film layer 18 is alumite sulfate is shown, the present invention is not limited thereto, and may be, for example, oxalic acid alumite, mixed acid alumite, or the like.

(3) In the present embodiment, the elastic body 12 uses stainless steel (SUS304) as an example. However, the elastic body 12 is not limited to this. For example, other various stainless steels (SUS303, SUS316, SUS410, etc.) and various steel materials ( S15C, S55C, SCr445, SNCM630, etc.), copper-based materials (brass, phosphor bronze, beryllium copper, aluminum bronze), aluminum alloys (A6061, A5056), and the like may be used.

(4) In the present embodiment, the example applied to the rotary vibration wave motor 10 is shown, but the present invention may be applied to a linear drive vibration wave actuator.

(5) In the present embodiment, the example in which the vibration wave motor is the vibration wave motor 10 that drives the moving body 13 by the progressive vibration wave is shown. However, the present invention is not limited to this. The present invention can be applied to vibration wave motors and actuators in general such as a vibration wave motor that drives a moving body.

(6) The present invention can also be applied to an electromechanical transducer that does not use vibration in the ultrasonic region.

(7) In this example, the fluororesin used for the electroless Ni-P / PTFE composite plating film layer 17 is PTFE. However, the fluororesin is not limited to this, and other fluororesins (PFA, FEP, PCTFE, ETFE, ECTFE, PVDF, PVF, etc.).

It is a figure which shows the Example of the vibration wave motor by this invention. It is sectional drawing which shows in detail the friction contact surface of the elastic body and moving body in the Example of the vibration wave motor by this invention. It is a table | surface which shows the drive result of the vibration wave motor of each Example by this invention and each comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vibration wave motor 11 Piezoelectric body 12 Elastic body 13 Moving body 14 Flexible printed circuit board 15 Vibration absorber 16 Support body 17 Electroless Ni-P / PTFE composite plating film layer 18 Alumite film layer

Claims (3)

A vibrator that generates vibration in an elastic body by excitation of an electromechanical transducer;
In a vibration wave motor comprising a relative motion member that is in pressure contact with the vibrator and performs relative motion with the vibrator by the vibration,
At least one of the portions including the frictional contact surface between the vibrator and the relative motion member is a composite coating layer formed of a transition metal and a self-lubricating substance, and the other is a porous oxide coating layer,
The composite coating layer and the porous oxide coating layer both have a Vickers hardness of 250 or more and a difference in Vickers hardness of 100 or less.
Vibration wave motor characterized by The vibration wave motor according to claim 1,
The composite coating layer is a composite plating layer formed of electroless nickel-phosphorus and fluororesin;
Vibration wave motor characterized by In the vibration wave motor according to claim 1 or 2,
The porous oxide film layer is a layer obtained by anodizing the surface of aluminum or aluminum alloy and forming an oxide film on the surface,
Vibration wave motor characterized by

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