JP3049931B2 - Ultrasonic motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor which generates a driving force by exciting an elastic wave using a piezoelectric material such as a piezoelectric ceramic. Regarding its structure.

[0002]

2. Description of the Related Art In recent years, attention has been paid to an ultrasonic motor that excites an elastic vibration to a vibrating body constituted by a piezoelectric body and uses the vibration as a driving force.

[0003] A conventional ultrasonic motor will be described below with reference to the drawings.

FIG. 11 is a partially cutaway perspective view showing a main part of a conventional annular ultrasonic motor. In the figure, reference numeral 3 denotes an annular vibrator, which is formed by bonding an annular piezoelectric body 2 to the bottom surface of an annular elastic substrate 1 having a plurality of projections 1a. Reference numeral 6 denotes a moving body, which is formed by connecting a wear-resistant friction material 5 to an annular elastic body 4. The ring-shaped vibrating body 3 and the moving body 6 are placed under pressure by appropriate pressing means so that the friction material 5 comes into pressure contact with the tip of the projection 1a.

Here, in the above-described conventional ultrasonic motor, as a material of the elastic body 4, a metal such as steel or stainless steel is conventionally used. The friction material 5 is joined by a method such as bonding to form a moving body 6 of the ultrasonic motor.

Next, the operating principle of the annular ultrasonic motor having the moving body 6 and the vibrating body 3 will be briefly described with reference to FIG. FIG. 13 shows the moving body 6 and the vibrating body 3.
Are in a pressure contact state with each other, and a traveling wave of bending vibration is excited in the vibrating body 3.

Excitation of the traveling wave of the bending vibration is performed as follows. First, two sets of drive electrodes are formed on the piezoelectric body 2. When two AC voltages having a predetermined phase difference are respectively applied to the drive electrodes, the piezoelectric body 2 expands and contracts and the elastic substrate 1 expands and contracts. Therefore, the traveling wave of the bending vibration is excited in the vibrating body 3 by the same effect as that of the bimetal.

At this time, an arbitrary point on the surface of the vibrating body 3 moves along an elliptical locus by the traveling wave of the bending vibration. The protrusion 1a enlarges the lateral displacement (楕 円 in FIG. 13) of the elliptical locus. The moving body 6 placed in pressure contact with the protrusion 1a of the vibrating body 3 is driven by frictional force due to the enlarged lateral displacement and rotates.

In the prior art, the following points are particularly important from the practical point of view.

First, as described above, the moving body 6 is
It is driven via a frictional force acting between the vibrating body 3 and the moving body 6 by the traveling wave of the bending vibration. Therefore, to realize stable driving, the moving body 6 and the vibrating body 3
Good contact with the body must be ensured.

For this purpose, the contact surface between the moving body 6 and the vibrating body 3 is required to have high-precision flatness processing of several μm or less. The material of the moving body 6 and the vibrating body 3 realizes this high-precision machining in view of providing rigidity such that the surface accuracy of the contact surface between the two does not change even when a pressing force is applied therebetween. In view of this, a metal material is used in most cases, and sometimes a ceramic material is used.

An important point in addition to the above-mentioned assurance of a good contact state is a measure against abrasion of the contact surface between the moving body 6 and the vibrating body 3. That is, when the ultrasonic motor is driven, the moving body 6
A frictional force acts on the contact surface between the vibration member 3 and the vibration member 3. Therefore, the state of contact between the two is always well maintained over time,
In order to perform a stable operation, it is extremely important to take measures to prevent the wear due to the frictional force from being generated as much as possible on the contact surface between the two.

If the contact surface wears, the flatness of the contact surface will be disturbed, making it difficult to ensure a uniform contact state, significantly reducing the efficiency of the ultrasonic motor, and preventing normal operation. . In addition, an abnormal sound is generated during operation. Furthermore, the generated abrasion powder reduces the reliability of the ultrasonic motor and the system in which it is used.

As a measure against the wear, a friction material 5 having excellent wear resistance is used. That is, when the moving body 6 made of a metal material and the vibrating body 3 are brought into direct contact with each other without using the friction material 5, abnormal wear such as a seizure phenomenon is caused on the contact surface, and a loud abnormal sound is generated. , Friction material 5
It intervenes.

The friction material 5 is described, for example, in Japanese Patent Application Laid-Open No. 62-58887 filed by the present applicant.

As the friction material 5, as described above, in addition to using a wear-resistant material completely different from the material of the elastic body 4, for example, the elastic body 4 is made of aluminum, and the vibrating body 3 is made of aluminum. There is also a configuration in which the surface layer of the contact surface is oxidized to form a so-called alumite layer, and this alumite layer is used as the friction material 5.

However, in the structure using the alumite layer as the wear-resistant material, the wear-resistance performance is remarkably inferior to that in the case of using the friction material composed of the carbon fiber and the resin, and stable operation is guaranteed for a long time. I can't.

The moving body 6 is connected to the elastic body 4 as described above.
In addition to the configuration in which the specific friction material 5 is joined to the moving body 6, the material of the moving body 6 is aluminum and an aluminum alloy, and the shape and dimensions of the moving body 6 are set within a specific range as shown in FIG. It has been proposed to realize an ultrasonic motor that does not generate abnormal noise, is quiet, and has high driving efficiency by adopting the configuration. (For example, see JP-A-63-17
No. 4581)

[0019]

However, the conventional ultrasonic motor has not been able to obtain satisfactory motor efficiency, motor life, and manufacturing cost.

As described above, in the prior art of the ultrasonic motor, (a) the flatness of the contact surface between the moving body and the vibrating body is processed with high precision to at least several μm or less, and It is necessary to ensure good contact with the vibrator. (B) In order to realize the above-mentioned high-precision machining of the contact surface and to secure this accuracy even under a stress applied state in which the moving body and the vibrating body are pressed against each other, the materials of the moving body and the vibrating body include: A material having a high elastic modulus such as a metal material or a ceramic material is used. There is a consistent philosophy that says.

Since a moving body is manufactured by processing a material having a high elastic modulus with a high degree of accuracy and further combining a wear-resistant material with the material, the manufacturing cost of the conventional ultrasonic motor is high. Has become a major obstacle.

In the ultrasonic motor described in Japanese Patent Application Laid-Open No. 63-174581, the moving body is more complicated, so that the manufacturing cost is higher and the abrasion-resistant material is an alumite layer. It decreases significantly.

In addition, the motor efficiency is at most 3
An efficiency of only about 0% is obtained. According to the technical idea of the conventional ultrasonic motor, in order to further improve the efficiency, it is necessary to further improve the processing accuracy of the contact surface between the moving body and the vibrating body. Is clearly inconsistent with the reduction of

An object of the present invention is to solve the above-mentioned conventional problems and to provide an ultrasonic motor having high efficiency, long life and low manufacturing cost.

[0025]

The ultrasonic motor of the present invention SUMMARY OF] To achieve this object, constituted by a carbon fiber reinforced resin composite alone reinforced using at least carbon fiber mobile and mobile , Moving body beam and both ends of the beam
Contact surface between the first protrusion of the moving body extending from the part and the vibrating body
And the second protruding portion of the moving body extending from the side beam portion .

[0026]

[Operation] That is, the material of the moving body is made of resin, and the moving body is moved.
A moving body beam portion and a moving body first extending from both ends of the beam portion
Movement extending from the protrusion and the beam on the contact surface side with the vibrator
With the configuration including the body second protrusion, an effect (surface correction effect) for absorbing the swell of the contact surface between the moving body and the vibrating body is generated. As a result, uniform contact between the moving body and the vibrating body can be stably maintained, the traveling wave of the bending vibration by the vibrating body can be efficiently transmitted to the moving body, and the motor efficiency is greatly improved. Conceivable.

That is, by using a structure in which the material of the moving body is made of resin and has elasticity corresponding to the pressing force of the ultrasonic motor in the pressing direction of the moving body, the contact surface between the moving body and the vibrating body can be formed. An effect (surface correction effect) for absorbing the undulation is generated. As a result, uniform contact between the moving body and the vibrating body can be stably maintained, the traveling wave of the bending vibration by the vibrating body can be efficiently transmitted to the moving body, and the motor efficiency is greatly improved. Conceivable.

By making the material of the moving body a resin composite in which carbon fibers are contained in a resin, for example, a suitable lubricating property can be imparted to the contact surface with the vibrating body and stable even during long-time driving. Motor characteristics can be maintained, and an ultrasonic motor having excellent long-term reliability can be realized.

Further, in this case, the resin composite itself containing carbon fibers is excellent in abrasion resistance. Therefore, as in the prior art, a step of bonding a friction material of another material or a treatment for making the surface layer a friction material is performed. It becomes unnecessary.

In addition to omitting this step, since the moving body of the resin material can be easily manufactured by molding, the manufacturing cost can be significantly reduced as compared with the conventional case.

The weight can be reduced by using a resin as the moving body, which is conventionally a metal material.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of a specific embodiment, a more detailed description will be given of the technical significance of forming the moving body with a resin material.

The ultrasonic motor uses the principle of operation shown in FIG. 13 to apply a traveling wave of bending vibration having an amplitude of about several microns (in FIG. 13) to a vibrating body composed of a piezoelectric body and an elastic substrate. This motor excites and expands the lateral displacement (ζ in FIG. 13) due to the traveling wave with the projection, and drives the moving body installed in pressure contact with the tip of the projection.

Accordingly, in order to realize an ultrasonic motor having a high efficiency and a long life, a contact state between the moving body and the vibrating body satisfying the following items is realized for a long time, and the traveling wave of the bending vibration by the vibrating body is obtained. It is indispensable to surely transmit to the moving body. (A) The moving body has dynamic elasticity at a macro length at the wavelength level of the traveling wave of the bending vibration by the vibrating body. This is necessary in order for the moving body to make uniform contact with the vicinity of the apexes of all the traveling waves and to efficiently transmit the traveling wave of the bending vibration by the vibrating body to the moving body.

As a measure of the dynamic elasticity, it is desirable that the amount of elastic deformation in the longitudinal direction of the moving body material when pressurized is within the range of the amplitude of the traveling wave or less as much as possible to the amplitude of the vibrating body. .

The optimum value of the dynamic elasticity varies depending on the pressing force of the ultrasonic motor and the number of traveling waves excited by the piezoelectric body, and is not uniquely determined, but depends on the driving conditions of the ultrasonic motor. Optimal design is required. (B) The moving body has rigidity in a micro length near the contact portion (A in FIG. 13) of the traveling wave of the bending vibration by the vibrating body. This is necessary to reduce output transmission loss due to elastic deformation of the moving body contact portion.

As a measure of the rigidity, it is necessary to suppress as much as possible the lateral elastic deformation of the moving body due to the lateral displacement of the traveling wave.

Further, in addition to the lateral displacement, it is necessary to suppress the lateral elastic deformation of the moving body due to an external load, and the optimum value of the rigidity required for the moving body is not uniquely determined. An optimum design is required according to the driving conditions of the ultrasonic motor. (C) The moving body has appropriate lubricity. this is,
It is necessary to maintain a stable frictional state and reduce wear. (D) The moving body has static elasticity according to the pressing force of the ultrasonic motor. This is necessary to absorb the undulation of the contact surface between the moving body and the vibrating body, and to ensure uniform contact.

The standard of the static elasticity varies depending on the machining accuracy of the vibrating body and the molding accuracy of the moving body or the pressing force of the motor.
It is desirable to make it about μm.

A conventional ultrasonic motor using an elastic body made of a metal material cannot sufficiently satisfy the above conditions (a) to (d), so that the motor has sufficient motor efficiency and life. Could not be obtained. In addition, as described above, the state was not sufficient in any respect, for example, the cost was high due to the complicated processing of the moving body.

The present invention, in order to further satisfy the condition of the (a) ~ (d), the mobile be those which Kinasa group Dzu new idea to say formed of a resin, as a result, the motor In any of the points of efficiency, life, and cost, the present invention has an effect far exceeding that of the conventional ultrasonic motor.

More specifically, in the present invention, attention is paid to the above items, and the material of the moving body is made of a carbon fiber reinforced resin composite reinforced at least using carbon fibers. In addition to increasing the rigidity of the micro length, the resin component has dynamic elasticity of the macro length.

[0043] As the case, the flexural modulus of the moving body material is desirably ^{1000kg / mm 2 ~7000kg / mm 2} .

The advantage of using carbon fibers is that the effect of improving the rigidity of the moving body is greater at the same fiber content as compared with inorganic fibers such as glass fibers, and therefore, the rigidity of the moving body is reduced at a lower fiber content. Can be enhanced,
This is because the mechanical strength of the moving body can be improved. In addition to the above, the use of carbon fibers imparts appropriate lubricity to the friction interface.

As a standard for the lubrication, it is desirable that the dynamic friction coefficient of the moving body material is in the range of 0.15 to 0.40.

Further, by making the structure of the moving body a structure having elasticity according to the pressing force of the moving body and the vibrating body, the undulation of the contact surface between the moving body and the vibrating body can be absorbed, and the uniform contact can be achieved. Can be improved and secured.

In the ultrasonic motor according to the present invention, since the moving body is formed of a resin composite, the pressure of the contacting portion of the moving body with the vibrating body is higher than when the moving body is made of a metal material. It is preferable to use a small value, especially 0.08 kgf
It is preferable to use a pressure in the range of / cm ^{2 to} 0.8 kgf / cm ² , but other ranges are also effective.

Accordingly, the ultrasonic motor of the present invention is particularly useful for relatively light load applications such as driving a lens of a camera or a VTR camera.

Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments.

(Embodiment 1) FIG. 1A is a configuration diagram of a main part of an ultrasonic motor according to an embodiment of the present invention. In the figure, reference numeral 13 denotes a moving body made of carbon fiber reinforced resin, which has a beam structure with both ends supported so as to have elasticity in a pressing direction (perpendicular to the surface A). More specifically, the movable body beam 10, the movable body first projection 11 extending from both ends of the beam 10, and the movable body second projection extending from the beam 10 on the contact surface side with the vibrating body 16. The moving body is constituted by the unit 12.

The vibrating body 16 has a rectangular projection 14.
A piezoelectric body 15 is connected to an elastic substrate 14 having a. The moving body 13 includes the moving body first protrusion 1.
The moving body second projection 12 contacts the vibrating body 16 by receiving a force pressed by the vibrating body 16 through the A surface 1. FIG.
(B) shows the cross-sectional shape of the moving body 13 in FIG.

In the case of this embodiment in which the moving body is made of carbon fiber reinforced resin, the contact state between the moving body and the vibrating body is improved as compared with the conventional case, the motor efficiency is improved, and the wear of the moving body is reduced. .

When the width W ₁ of the second protrusion 12 of the moving body of this embodiment is less than 0.3 mm, pressure tends to be concentrated on the second protrusion of the moving body, and the wear of the moving body is high. And there is a problem in terms of long-term reliability.

If W ₁ is larger than 2.0 mm, the motor characteristics will vary due to the difference in the contact state, making it difficult to ensure stable and uniform contact.

Therefore, in the present embodiment, the width W ₁ is set to 0.
It is necessary to set it within the range of 3 mm or more and 2.0 mm or less.

Reference Example 1 Next, in the ultrasonic motor of the first reference example shown in FIG. 2, the moving body 23 has a beam structure under one-end support conditions, so that elasticity is provided in the pressing direction. It is a moving body. That is, the moving body 23
The moving body beam portion 20, the moving body first protrusion 21 extending from one end of the moving body beam portion 20, and the moving body second protrusion extending from the other end of the moving body beam portion 20 22.

The vibrating body 16 is a rectangular projection 1.
The piezoelectric body 15 is formed by bonding the piezoelectric body 15 to an elastic substrate 14 having 4a.

Then, the moving body 23 receives the force pressed by the vibrating body 16 through the surface B of the first moving body projection 21 and contacts the vibrating body 16 with the second moving body projection 22. ing.

FIG. 2B is a cross-sectional view of the movable body having the beam structure supported at one end shown in FIG. 2A. In FIG. 2B, the length of the movable body beam is L, the thickness of the movable body beam is T, the width of the movable body second projection is W ₂ , and the height of the movable body second projection is H. The dimensional relationship of each part will be described below.

First, as for the ratio L / T of the length L of the moving beam portion to the thickness T of the moving beam portion, if the ratio is 2 or more, the mechanical strength of the moving member becomes insufficient and Since the output transmission efficiency is reduced due to the resonance of the movable beam,
It turns out that it needs to be set to less than.

Next, when the ratio H / T of the height H of the second protrusion of the moving body to the thickness T of the beam of the moving body is larger than 2, the mechanical strength of the moving body is high. Is insufficient, and when the external load is applied, the movable body second projection is deformed to lower the output transmission efficiency.
It turned out that it was necessary to set the following.

Further, when the width W ₂ of the second protrusion of the moving body is less than 0.3 mm, pressure concentrates on the second protrusion of the moving body, the wear of the moving body is accelerated, and the long-term reliability is improved. If there is a problem with the property and it is larger than 2.0 mm,
Differences in the contact state cause variations in the motor characteristics, making it difficult to ensure stable and uniform contact.
It turned out that it is necessary to set it within the range of 3 mm or more and 2.0 mm or less.

In order to efficiently transmit the traveling wave of bending vibration by the vibrating body to the moving body, it is necessary to set the dimensions of the moving body within the above range.

Further, since the rigidity and elasticity in the pressing direction required for the moving bodies 13 and 23 depend on the pressing force of the ultrasonic motor, the content of the carbon fiber contained in the carbon fiber reinforced resin composite and the By adjusting the length or thickness of the beam of the moving body, the rigidity of the moving bodies 13 and 23 and the elasticity in the pressing direction can be adjusted.

Next, this embodiment will be described in more detail.

The moving body 23 is composed of 30% by weight of carbon fiber and 7% by weight.
By injection-molding a kneaded material with 0% by weight of a polyphenylene sulfide resin, the ratio L / T of the length L of the movable beam to the thickness T of the movable beam in FIG.
The ratio H / T of the height H of the movable body second projection to the thickness T of the movable body beam is 1.18, and the width W _{2 of} the movable body second projection is 1.0 m.
m.

Next, the outer diameter of the movable body 23 is φ48 mm.
0.13 kgf using a disc spring
The ring-shaped ultrasonic motor was constructed by pressure contact with a pressure of / cm ² .

Next, with respect to the ultrasonic motor of this embodiment ,
The characteristics were evaluated and confirmed.

First, regarding the motor efficiency, in the annular ultrasonic motor of this embodiment, the efficiency reaches a maximum of 44%.
The efficiency was improved by about 50% as compared with the conventional ultrasonic motor.

[0070] Next, the results of the evaluation of the life of the motor, this participation
In the ultrasonic motor according to the example, almost no characteristic deterioration was observed even after the cumulative rotation number of 2,000,000 rotations.

The high efficiency and the long life of the motor of this embodiment are far superior to those of the conventional ultrasonic motor as described below.

First, in order to compare the ultrasonic motor of the present embodiment with a conventional ultrasonic motor, in particular, in order to compare the effect due to the difference with a moving body, see Japanese Patent Application Laid-Open No. 63-1745.
A moving body having the shape shown in FIG. 12 proposed in Japanese Patent Publication No. 81 was made of aluminum, and a conventional ultrasonic motor was made using this moving body.

The ratio L / t ¹ of the length L of the flange portion to the thickness t ¹ of the flange portion of the moving body of the conventional structure is 6.5, the height t ² of the contact portion of the moving body and the height of the flange portion. Ratio t ² with thickness t ¹
/ T ¹ is 2.5, and the height T ¹ of the mobile body is 3.2 mm
The width of the main body of the moving body was set to 2.0 mm, which was within the recommended range in the above-mentioned Japanese Patent Application Laid-Open No. 63-174581. In addition, the contact surface of the moving body that comes into contact with the vibrating body
Low temperature alumite treatment was applied to improve wear resistance.

In order to clarify the effect due to the difference between the moving bodies, for the conventional ultrasonic motor for comparison, the conditions such as the shape and dimensions of the vibrating body and the pressing force between the moving body and the vibrating body are set in accordance with the present invention. Efficiency and life were evaluated in the same manner as in the reference example .

As a result, in the conventional annular ultrasonic motor in which the moving body is made of aluminum, the efficiency is at most 30.
%, And when the cumulative number of rotations reached about 400,000 rotations, the rotation became unstable and the motor efficiency decreased with time.

As described above, the ultrasonic motor of this embodiment is
Both the efficiency and the service life are remarkably improved and improved as compared with the conventional one.

Further, the shape and dimensions of this conventional moving body are
In order to produce the material within the above-mentioned specific range, complicated processing is required, a low-temperature alumite treatment for improving abrasion resistance is required, and the production cost is high.

However, in the moving body of the present embodiment , the moving body can be formed by injection molding or the like, and since the moving body itself has wear resistance, a conventional friction material is not required. It can be manufactured in a simple process at low cost.

Actually, in the case of the present embodiment, which can be manufactured by molding and does not require a friction material, the moving body having the shape shown in FIG.
The manufacturing cost was significantly reduced as compared with the conventional example manufactured by machining such as polishing. As a result, the cost of the ultrasonic motor as a finished product was significantly reduced. As described above, the ultrasonic motor according to the present embodiment has a remarkable effect in terms of cost.

[0080] Further, Comparing the weight of the moving body, whereas the specific gravity of aluminum is 2.70, the reference
Since the specific gravity of the moving body material in the example is 1.45, the weight of the moving body can be reduced to about half when a moving body of the same size is formed, which greatly contributes to the weight reduction of the ultrasonic motor. be able to.

In the above reference example , the case where the pressure between the moving body and the vibrating body is 0.13 kgf / cm ² has been described. However, the shape and dimensions of the moving body in FIG. /
By optimizing within the range of T ≦ _2, 0.3 mm ≦ W ₂ ≦ 2.0 mm, the pressing force is 0.08 kgf / cm ² to 0.3 mm.
In the range of 8 kgf / cm ² , the efficiency is up to 40%
It was confirmed that the above was obtained.

(Embodiment 2 ) In an ultrasonic motor according to a second embodiment of the present invention, as shown in FIG. 3A, a moving body 50 is pressed against a vibrating body 32 by using a disc spring (not shown). This is an annular ultrasonic motor configured in contact.

The ring-shaped vibrating body 32 is a ring-shaped elastic substrate 3 made of stainless steel and having a plurality of rectangular projections 30a.
The structure is such that a ring-shaped piezoelectric body 31 is adhered to the bottom surface of the “0”.

The toroidal moving body 50 is formed by injection molding a kneaded product of 30% by weight of carbon fiber and 70% by weight of polyphenylene sulfide resin.
The specific gravity is 1.45.

The moving body 50 has a sectional shape shown in FIG. Then, an example of the dimensional relationship of each portion of the vehicle 50 in the present embodiment, if the width of the moving body second projection 50b of the vehicle 50 in contact with the vibration member 32 and the W _3, a percentage of this W ₃ Shown in the figure,
It has a mobile beam portion 50c having a length of 3W _3, a mobile first protrusions 50a having a width of 3W _3/2, a mobile second protrusion 50b having a width of W _3, the mobile Second protrusion 5
At 0b, it is in contact with the vibrating body 32.

In this embodiment, too, the moving beam 50
By optimizing the length c, the width of the movable body second projection 50b, the thickness of the movable body beam 50c, and the height of the movable body second projection 50b according to the pressing force of the ultrasonic motor. Therefore, the same effect as that of the first embodiment can be obtained.

(Embodiment 3 ) In an ultrasonic motor according to a third embodiment of the present invention, as shown in FIG. 4A, a moving body 51 is attached to a vibrating body 32 similar to that of the second embodiment by a coned spring (not shown). ) Is a ring-shaped ultrasonic motor configured by pressurizing contact.

The toroidal moving body 51 is formed by injection molding a kneaded product of 30% by weight of carbon fiber and 70% by weight of polyethersulfone resin, and has a specific gravity of 1.47.

The cross-sectional shape of the moving body 51 is as shown in FIG. Then, the moving body 51 in the present embodiment
Of an example of the dimensional relationship of each portion, if the width of the moving body second projection portion 51b of the moving body 51 in contact with the vibration member 32 and the W _4, is shown in Figure a percentage of this W _4, mobile length of the beam portion 51c is 3W _4, the width of the moving body first projection portion 51a has a width of 3W _4/2, the mobile second protrusion 51b is W _4. Then, the moving body second projection 51b is connected to the moving body beam 5
The movable body second projection 51b is formed on the inner peripheral side of the center of 1c, and is in contact with the vibrating body 32.

The moving body second projection 51b is moved to the moving body beam 51.
By providing the inner peripheral side of c, it is possible to have a larger surface correction effect on the outer peripheral side of the moving body than on the inner peripheral side, and the radial amplitude of the toroidal vibrating body becomes larger on the outer peripheral side. The moving body can be designed in consideration of the amplitude in the radial direction, which is larger.

It is needless to say that the same effects as those of the first embodiment can be obtained in improving the motor efficiency and life, and reducing the manufacturing cost.

(Embodiment 2 ) In the ultrasonic motor of the second embodiment, as shown in FIG. 5A, a moving body 52 is formed by using a coned disc spring (not shown) for the vibrating body 32 similar to the second embodiment. This is a ring-shaped ultrasonic motor configured to be in contact with and pressurized.

The toroidal moving body 52 is formed by injection molding a kneaded product of 30% by weight of carbon fiber and 70% by weight of polyphenylene sulfide resin.
The specific gravity is 1.45.

The cross-sectional shape of the moving body 52 is as shown in FIG. An example of the dimensional relationship of each part of the moving body 52 in the present reference example is described below.
If the width of the second moving body second projection portion 52b was set to W _5, it is shown in Figure a percentage of this W _5, the moving body beam portion 5
The length of 2c is 3W _5/2, the width of the moving body first projection portions 52a extending from the outer periphery of the moving body beam portion 52c is 3W _5/2, mobile extending from the inner periphery of the moving body beam portion 52c Second protrusion 5
The width of 2b is W _5, and the moving body second projection portion 52b is brought into contact with the vibrating body 32.

The length of the movable body beam 52c, the width of the movable body second projection 52b, the thickness of the movable body beam 52c, and the height of the movable body second projection 52b are determined by the pressing force of the ultrasonic motor. By optimizing according to, the same effect as in Reference Example 1 can be obtained.

(Embodiment 3 ) In the ultrasonic motor of the third embodiment , as shown in FIG. 6A, a moving body 53 is formed by using a disc spring (not shown) for the vibrating body 32 similar to the second embodiment. This is a ring-shaped ultrasonic motor configured to be in contact with and pressurized.

The toroidal moving body 53 is formed by injection molding a kneaded product of 30% by weight of carbon fiber and 70% by weight of polyether-terketone resin.
The specific gravity is 1.44.

The cross-sectional shape of the moving body 53 is shown in FIG.
As shown in FIG. And the moving body 53 in the present reference example
Of an example of the dimensional relationship of each portion, if the width of the moving body second projection portion 53b of the moving body 53 in contact with the vibration member 32 has a W _6, is shown in Figure as a percentage of the W _6, mobile The length of the beam portion 53c is W ₆ , the width of the first protrusion 53a of the movable body extending from the inner periphery of the movable beam portion 53c is W ₆ , and the second of the movable body extending from the outer periphery of the movable beam portion 52c. The width of the projection 53b is W ₆ , and the movable body second projection 53b is in contact with the vibrator 32.

The movable body second projection 53b is moved to the movable body beam 53.
In the ultrasonic motor of the present embodiment provided on the outer peripheral side of c,
In addition to the effects described in Reference Example 1 , it is possible to reduce the outer diameter of the moving body, and it is possible to obtain a smaller and lighter moving body and ultrasonic motor.

(Embodiment 4 ) In an ultrasonic motor according to a fourth embodiment , as shown in FIG. 7A, a moving body 54 is formed by using a disc spring (not shown) for the vibrating body 32 similar to the second embodiment. This is a ring-shaped ultrasonic motor configured to be in contact with and pressurized.

The annular moving body 54 is formed by injection molding a kneaded product of 30% by weight of carbon fiber and 70% by weight of polyethersulfone resin, and has a specific gravity of 1.47.

The sectional shape of the moving body 54 is as shown in FIG. An example of the dimensional relationship of each part of the moving body 54 in the present reference example is described by using the moving body 5
If the mobile of 4 the width of the second protrusion 54b and a W _7, is shown in the figure as a percentage of this W _7, the moving body beam portion 5
The length of the 4c is 3W _7/4, the width of the moving body first projection portions 54a extending from the outer periphery of the moving body beam portion 54c is 9W _7/8, the moving body extending from the inner periphery of the moving body beam portion 54c Second protrusion 5
The width of 4b is W _7, the contact surface side of the moving body beam portion 54c is tapered form. Then, the movable body second protrusion 54b is brought into contact with the vibrating body 32.

In the ultrasonic motor of this embodiment , as described above, the taper is provided on the side of the movable body beam portion 54c on the vibrating body 32 side, thereby increasing the rigidity of the movable body contact portion and simultaneously improving the surface correction effect. It is possible to increase.

(Embodiment 4 ) In an ultrasonic motor according to a fourth embodiment of the present invention, as shown in FIG. 8A, a moving body 55 is pressed against a vibrating body 42 by using a disc spring (not shown). This is an annular ultrasonic motor configured in contact.

The vibrating member 42 includes a plurality of trapezoidal projections 4.
A ring-shaped piezoelectric body 41 is adhered to the bottom surface of a ring-shaped elastic substrate 40 made of stainless steel having Oa.

The toroidal moving body 55 is formed by injection molding a kneaded product of 30% by weight of carbon fiber and 70% by weight of polyphenylene sulfide resin.
The specific gravity is 1.45.

The sectional shape of the moving body 55 is shown in FIG.
As shown in FIG. The moving body 55 in the present embodiment
Of an example of the dimensional relationship of each portion, if the width of the moving body beam portion of the movable body 55 in contact with the vibration member 42 has a W _8, it is shown in Figure a percentage of this W _8, the mobile beam portion 55c Is 2W ₈ , the width of the movable body projection 55a is W ₈ , and the movable body beam 55c is in contact with the vibrating body 42 at a contact width of W ₈ .

In the ultrasonic motor according to the present embodiment, the length of the movable beam 55c and the thickness of the movable beam 55c are optimized according to the pressing force of the ultrasonic motor. The same effect can be obtained.

(Embodiment 5 ) As shown in FIG. 9 (a), an ultrasonic motor according to a fifth embodiment of the present invention includes a moving body 56 having the same vibrating body 42 as in the fourth embodiment.
A ring-shaped ultrasonic motor is formed by pressing and contacting using a disc spring (not shown).

The annular moving body 56 is formed by injection molding a kneaded product of 30% by weight of carbon fiber and 70% by weight of polyether-terketone resin.
The specific gravity is 1.44.

The cross-sectional shape of the moving body 56 is shown in FIG.
As shown in FIG. The moving body 56 in the present embodiment
Of an example of the dimensional relationship of each portion, if the width of the moving body beam portion of the movable body 56 in contact with the vibration member 42 has a W _9, it is shown in Figure a percentage of this W _9, the mobile beam portion 56c the length of 2W _9, the width of the moving body projections 56a are W _9, the taper provided on the side surface of the vibrating body 42 side of the moving body beam portion 56c, the contact width of W ₉ of the moving body beam portion 56c The vibrator 42 is in contact with the vibrator 42.

In the ultrasonic motor according to the present embodiment, as described above, the taper is provided on the contact surface side of the beam portion of the moving body, so that the rigidity of the contacting portion of the moving body can be increased and the surface correction effect can be increased. It becomes possible.

(Embodiment 6 ) An ultrasonic motor according to a sixth embodiment of the present invention will be described with reference to FIG.
As shown in the same vibrating body moving body 57 as in Example 4 42
A ring-shaped ultrasonic motor is formed by pressing and contacting using a disc spring (not shown).

The toroidal moving body 57 is formed by injection molding a kneaded product of 30% by weight of carbon fiber and 70% by weight of polyethersulfone resin, and has a specific gravity of 1.47.

The sectional shape of the moving body 57 is shown in FIG.
This is as shown in FIG. And an example of the dimensional relationship of each portion of the moving body 57 in the present embodiment, the width of the moving body beam portion of the movable body 57 in contact with the vibrating body 42 as W _10, the W
It is shown in the figure at a ratio of ₁₀ to the moving beam 57c.
The length of 8W _10/3, the width of the moving body projections 57a is 2W ₁₀
/ 3 and the rear surface side of the moving body beam portion 57c is an angle different taper provided, it is brought into contact with the vibrating body 42 in the contact width of the W ₁₀ of the mobile beam portion 57c.

In the ultrasonic motor according to the present embodiment, the outer peripheral side of the movable body is made larger in taper than the inner peripheral side so that the outer peripheral side of the movable body has a greater surface correction effect than the inner peripheral side. The moving body can be designed in consideration of the radial amplitude, in which the radial amplitude of the ring-shaped vibrating body is larger on the outer peripheral side.

As shown in each of the above embodiments, in the ultrasonic motor of the present invention, the moving body is constituted by a carbon fiber reinforced resin composite unit reinforced using at least carbon fiber, thereby achieving the conventional annular shape. Unlike the mold ultrasonic motor, there is no need for a bonding process for bonding the friction material to the metal elastic body, and the moving body is easily and inexpensively manufactured using a mold by a method such as injection molding or compression molding. It is possible to mold into.

Further, by adopting the above configuration, the moving body is compared with a moving body of the same size formed by connecting a friction material to a stainless steel elastic body like a conventional annular ultrasonic motor. Thus, the weight of the moving body can be reduced.

Although the specific embodiments have been described above, in each of the above embodiments, the content of carbon fibers contained in the carbon fiber reinforced resin composite constituting the moving body is determined by the pressing force of the ultrasonic motor. When the fiber content is less than 5% by weight, the effect for improving the rigidity is insufficient, and the wear resistance of the frictional contact surface of the moving body is insufficient. When the fiber content is more than 50% by weight, it depends on the molding method or the fluidity of the resin, but the molding becomes difficult and at the same time the mechanical strength of the molded product becomes brittle.
It must be in the range of 5% by weight to 50% by weight.
15% by weight when comprehensively judged from the material characteristics required for the moving body, the moldability of the moving body, the cost of the moving body, etc.
It is desirable that the content be at least 35% by weight.

In each of the above embodiments, carbon fiber was used as the type of reinforcing fiber. However, it is equally possible to use the carbon fiber in combination with an inorganic fiber other than carbon fiber. In order to adjust the lubricating property, it is also possible to combine an inorganic filler such as a graphite powder, an ethylene tetrafluoride powder, a molybdenum sulfide powder and a fluorinated graphite powder with the above-mentioned fibers.

Further, in each of the above embodiments, as the resin constituting the carbon fiber reinforced resin composite, a polyphenylene sulfide resin, a polyether-terketone resin,
Although a thermoplastic resin such as polyethersulfone resin was used, the present invention is not limited to these. As a guide when selecting a resin constituting the carbon fiber reinforced resin composite, it is desirable to use a resin having a heat resistance of 150 ° C. or higher and a high heat deformation temperature. However, when a resin having a low heat distortion temperature of 150 ° C. or less is used, it is difficult to secure long-term reliability, for example, the wear of the friction contact portion of the moving body is promoted, and the motor performance is deteriorated. It is.

[0122] The above aspect based Dzu fluff, other than resin shown in the examples, polysulfone resin, polyarylate resin, polyamideimide resin, polyetherimide resin, polyimide resin, thermoplastic resins such as wholly aromatic polyester resin or It is similarly possible to use a thermosetting resin such as a phenol resin, a bismaleimide / triazine resin, or a polyimide resin.

[0123]

As described above, according to the present invention, the moving body is made of a carbon fiber reinforced resin reinforced by using at least carbon fiber , and the moving body is made of a moving body beam and both ends of the beam.
Contact surface between the first protrusion of the moving body extending from the part and the vibrating body
And the second protruding part of the moving body extending from the beam on the side.
This makes it possible to realize a high-efficiency, high-reliability, long-life, lightweight, and inexpensive ultrasonic motor.

In particular, considering that the improvement of efficiency, reliability and life and the reduction of price are the biggest bottlenecks for practical use of an ultrasonic motor, the effect of the present invention on industry is very large.

In particular, reduction of power consumption, weight reduction, reliability, etc. are required.
This is extremely useful for applications such as driving a camera lens.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view illustrating a main part of an ultrasonic motor according to a first embodiment of the present invention; FIG. 1B is a cross-sectional view illustrating a cross-sectional shape of a moving body of the motor according to the first embodiment;

FIG. 2A is a cross-sectional view illustrating a main configuration of a first reference example ; FIG. 2B is a cross-sectional view illustrating a cross-sectional shape of a moving body of the reference example motor;

FIG. 3A is a cross-sectional view illustrating a configuration of a main part of a second embodiment of the ultrasonic motor according to the present invention. FIG. 3B is a cross-sectional view illustrating a cross-sectional shape of a moving body of the motor according to the second embodiment.

FIG. 4A is a cross-sectional view illustrating a configuration of a main part of a third embodiment of an ultrasonic motor according to the present invention. FIG. 4B is a cross-sectional view illustrating a cross-sectional shape of a moving body of the motor according to the third embodiment.

FIG. 5A is a cross-sectional view illustrating a main configuration of a second reference example . FIG. 5B is a cross-sectional view illustrating a cross-sectional shape of a moving body of the reference example motor.

FIG. 6A is a cross-sectional view illustrating a main configuration of a third reference example ; FIG. 6B is a cross-sectional view illustrating a cross-sectional shape of a moving body of the reference example motor;

FIG. 7A is a cross-sectional view illustrating a main configuration of a fourth reference example ; FIG. 7B is a cross-sectional view illustrating a cross-sectional shape of a moving body of the reference example motor;

FIG. 8A is a cross-sectional view showing a main configuration of an ultrasonic motor according to a fourth embodiment of the present invention. FIG. 8B is a cross-sectional view showing a cross-sectional shape of a moving body of the motor according to the fourth embodiment.

FIG. 9A is a cross-sectional view illustrating a main configuration of an ultrasonic motor according to a fifth embodiment of the present invention. FIG. 9B is a cross-sectional view illustrating a cross-sectional shape of a moving body of the motor according to the fifth embodiment.

FIG. 10A is a cross-sectional view illustrating a configuration of a main part of a sixth embodiment of the ultrasonic motor according to the present invention. FIG. 10B is a cross-sectional view illustrating a cross-sectional shape of a moving body of the motor according to the sixth embodiment.

FIG. 11 is an exploded perspective view showing the main components of a conventional annular ultrasonic motor.

FIG. 12 is a cross-sectional view showing the structure of a moving body of a conventional annular ultrasonic motor.

FIG. 13 is an explanatory diagram of the operation principle of the ultrasonic motor.

[Explanation of symbols]

1, 14, 30, 40 Elastic substrate 1a, 14a, 30a, 40a Projection 2, 15, 31, 41 Piezoelectric 3, 16, 32, 42 Vibrator 4 Elastic 5 Friction material 6, 13, 23, 50, 51, 52, 53, 54, 5
5, 56, 57 Moving body 10, 20 Moving body beam 11, 21 Moving body first projection 12, 22 Moving body second projection

────────────────────────────────────────────────── ─── Continuation of the front page (72) Osamu Kawasaki, inventor 1006 Kazuma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-63-136984 (JP, A) 114481 (JP, A) JP-A-2-197272 (JP, A) JP-A-2-285974 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02N 2/00

Claims (2)

(57) [Claims] 1. A vibrating body in which a piezoelectric body is coupled to an elastic substrate,
An ultrasonic motor that moves the moving body through frictional force between the vibrating body and the moving body by pressing the moving body into contact with the moving body and exciting a traveling wave of bending vibration to the vibrating body.
In the above, the moving body is composed of a carbon fiber reinforced resin composite reinforced at least with carbon fibers, and has a beam structure with both ends supported, and the moving body has a moving body beam portion.
And a first protrusion of the moving body extending from both ends of the beam portion
And the moving body second extending from the beam on the contact surface side with the vibrating body
An ultrasonic motor characterized by comprising a projection.
Ta. 2. A movable body extending from a movable body beam, a movable body first projection extending from both ends of the movable body, and a movable body extending from a beam on a contact surface side with the vibrating body. constituted by a two projections, and when the width of the second protrusion mobile was W _1, the ultrasonic motor according to claim 1, wherein the set to 0.3 mm ≦ W ₁ ≦ 2.0 mm .