JPH05207763A - Driving mechanism - Google Patents

Abstract

PURPOSE:To provide a driving mechanism in which operating power of rotor is enhanced through negative pressure suction of fluid and downsizing and thinning are realized by employing a flat structure. CONSTITUTION:The driving mechanism comprises a first oscillator 8 comprising a first electromechanical converting element 6 and an oscillation board 7 contacting therewith, and a second oscillator 5 comprising a stator 4 contacting with the oscillation board 7 at the outer periphery thereof and a second electromechanical converting element connected with the stator 4 to oscillate the first oscillator 8 in predetermined direction. The driving mechanism further comprises a rotor 9 which contacts through fluid 10 with the oscillation board 7 and means for controlling the driving of electromechanical converting elements which drives the first electromechanical. converting element 6 to oscillate the first oscillator 8 and drives the second electromechanical converting element in appropriate phase relationship with the first electromechanical converting element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving mechanism used as a small actuator for OA equipment.

[0002]

2. Description of the Related Art In recent years, ultrasonic type actuators utilizing ultrasonic waves have been attracting attention as actuators that are compact, have high output, high efficiency, and are suitable for constant speed and low speed driving. As this ultrasonic type actuator, for example, as a first conventional example thereof, there is a type based on a thrust vibrating piece drive system as disclosed in Japanese Patent Publication No. 59-37672. This is to move the moving element by ultrasonically vibrating it while the rod-shaped vibrator is tilted and is in contact with the moving element. As a second conventional example, there is a spiral mode drive system as disclosed in Japanese Patent Laid-Open No. 62628/1985. In this, inclined teeth are provided between the vibrator and the mover, and the mover is moved by utilizing the bending of the inclined teeth due to the vibration of the vibrator. Further, as a third conventional example thereof, there is a traveling wave drive system as disclosed in Japanese Patent Laid-Open No. 58-148682. This is to move the moving element by bringing the moving element into pressure contact with the surface of the oscillator in which the traveling wave is excited. Furthermore, as the fourth conventional example, there is a system using a longitudinal-torsion oscillator driving method as disclosed in Japanese Patent Laid-Open No. 61-121777.
In this system, an elliptical vibration is generated by appropriately driving the vertical vibrator and the torsional vibrator in synchronization, and thereby the mover is moved.

[0003]

In the case of the thrust vibrating piece driving method of the first conventional example, it is possible to obtain a high driving efficiency, but the vibrating piece is severely worn, resulting in poor durability. There is. Also, in the case of the spiral mode drive system of the second conventional example, since the sliding surface is wide, there is little wear, but since it is a one-way drive and a simple friction drive system, it is suitable for the sliding surface. It is troublesome because adjustments such as tightening with bolts are required to obtain a proper crimping force. Furthermore, in the case of the traveling wave drive system of the third conventional example, bidirectional drive is possible, but since the proportion of the portion that actually contributes to friction on the sliding surface is small, the actuator size is relatively small. There is a problem that the output is small. Furthermore, in the case of the vertical-torsion oscillator driving method of the fourth conventional example, bidirectional driving is possible, but it is necessary to adjust the crimping force as in the case of the second conventional example.

[0004]

According to a first aspect of the invention, there is provided a first vibrating body including a first electromechanical conversion element and a vibrating plate in contact with the element, and the first vibrating body is in contact with the outer peripheral portion of the vibrating plate. A second vibrating body including a stator and a second electromechanical conversion element that is connected to the stator and vibrates the first vibrating body in a predetermined direction is provided, and a rotor that is in contact with the vibrating plate via a fluid is provided. Electromechanical conversion element drive control means for driving the first electromechanical conversion element to vibrate the first vibrating body and to drive the second electromechanical conversion element in an appropriate phase with the first electromechanical conversion element is provided.

According to a second aspect of the present invention, in the first aspect of the present invention, the diaphragm and the rotor of the first vibrating body are formed into a disc shape, and their respective surfaces are brought into surface contact with each other, whereby the first electromechanical conversion is performed. By driving the element, the contact surface of the vibrating plate, which is in surface contact with the rotor, is displaced into a convex shape or a concave shape.

According to the invention of claim 3, claim 1 or 2
In the invention described above, the seal member for sealing the periphery of the fluid interposed in the contact portion between the vibration plate of the first vibrating body and the rotor is provided.

[0007]

According to the first aspect of the invention, the first electromechanical conversion element is driven to vibrate the first vibrating body to generate a pressure change in the fluid, and the contact pressure between the first vibrating body and the rotor is increased. Can be changed, and the rotor can be driven by driving the second electromechanical conversion element with the first electromechanical conversion element in an appropriate phase.

According to the second aspect of the present invention, by driving the first electromechanical conversion element, the contact surface of the first vibrating body that is in surface contact with the rotor is changed into a convex shape or a concave shape.
It is possible to generate a pressure change on the contact surface with the rotor formed in a disc shape.

According to the third aspect of the invention, by sealing the fluid, it is possible to further enhance the sealed state of the fluid.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. First, the overall configuration will be described with reference to FIGS. 1 and 2. Anchors 2a, 2 are provided at the end on the base 1.
b is provided. The anchors 2a, 2b have a second
One ends of the laminated piezoelectric elements 3a and 3b as electromechanical conversion elements are attached. The other ends of the laminated piezoelectric elements 3a and 3b are attached to the circumferential portion of a circular stator 4. As a result, the stator 4 becomes the laminated piezoelectric element 3
It vibrates in the circumferential direction by the displacement of a and 3b. The laminated piezoelectric elements 3a and 3b and the stator 4 constitute a second vibrating body 5.

A hole 4a is formed in the center of the stator 4, and a flat piezoelectric element 6 as a first electromechanical conversion element is provided on the bottom surface of the stator 4 with the hole 4a. ing. The piezoelectric element 6 has one surface fixed to a disk-shaped vibrating plate 7. This diaphragm 7
Has its outer peripheral portion fixed to the stator 4. The piezoelectric element 6 and the vibrating plate 7 form a first vibrating body 8. A disc-shaped rotor 9 is rotatably guided in the hole 4a. This rotor 9
Oil 10 as a fluid is interposed between the diaphragm 7 and the vibrating plate 7 so that bubbles and the like do not enter.
Therefore, the vibration plate 7 and the rotor 9 are in surface contact with each other through the oil 10. The fluid may be general mechanical oil, water, silicone oil, or grease having a relatively high viscosity.

Further, here, electromechanical conversion element drive control means (not shown) is provided. The electromechanical conversion element drive control means drives the piezoelectric element 6 to vibrate the first vibrating body 8 to cause a pressure change in the oil 10, and thereby the contact pressure between the first vibrating body 8 and the rotor 9 is increased. And by driving the laminated piezoelectric elements 3a and 3b with the piezoelectric element 6 in an appropriate phase.
Has the function of moving.

The operation principle of rotating the rotor 9 in one direction by using the electromechanical conversion element drive control means in such a configuration will be described. First, by driving the piezoelectric element 6, the vibrating plate 7 generates surface vibration, and the central portion thereof is deformed into a convex shape or a concave shape and vibrates. FIG. 3A shows a state where the vibration plate 7 is deformed into a convex shape. The vibration plate 7 makes only a slight surface contact at the central portion of the rotor 9, and the rotation of the rotor 9 at this time. The binding force in the direction (arrow direction) becomes smaller. On the other hand, FIG. 3B shows a state in which the diaphragm 7 is deformed into a concave shape. The oil 10 is in a negative pressure state and acts so as to attract the rotor 9 to the diaphragm 7. As a result, the outer peripheral portion of the rotor 9 is pressed by the vibrating plate 7, and at this time, the rotation direction of the rotor 9 is largely restricted by the vibrating plate 7 and is substantially fixed to the vibrating plate 7.

Further, since the laminated piezoelectric elements 3a and 3b are simultaneously driven to vibrate the stator 4 in the rotation direction, the vibrating plate 7 fixed to the outer peripheral portion of the stator 4 also vibrates in the rotation direction.

From the above, the driving of the piezoelectric element 6 and the laminated piezoelectric elements 3a and 3b is synchronized by the electromechanical conversion element drive control means, and the rotor 9 and the diaphragm 7 are connected as shown in FIG. 3B. Rotating the rotor 9 in one direction by matching the phase of rotational vibration of the stator 4 when the binding force is large and when the binding force between the rotor 9 and the diaphragm 7 is small as shown in FIG. 3A. It becomes possible.

As described above, by using the negative pressure action of the oil 10, a force stronger than the conventional pressing force simply caused by the displacement of the piezoelectric element can be drawn out.
The operating force of the rotor 9 can be further improved. Further, since the contact portion between the vibration plate 7 and the rotor 9 is set to the outer circumference and the inner circumference, the generation of the rotation moment can be effectively utilized, so that the smoother rotation can be performed. Further, since the rotating portion has a flat shape, it is possible to reduce the thickness and size of the entire device. Furthermore, by interposing the oil 10 between the vibration plate 7 and the rotor 9, it is possible to prevent deterioration of durability due to wear or the like.

Next, a second embodiment of the present invention will be described with reference to FIG. The description of the same parts as those in the first embodiment described above is omitted, and the same reference numerals are used for the same parts. Here, an O-ring 11 is provided as a seal member that seals around the oil 10 interposed between the vibration plate 7 of the first vibrating body 8 and the rotor 9.
In this case, the O-ring 11 is arranged in the region of the groove 12 formed in the contact surface between the vibration plate 7 and the rotor 9. By thus providing the O-ring 11 to enhance the hermetically sealed state of the oil 10, a large restraining force between the diaphragm 7 and the rotor 9,
It becomes possible to further increase the small difference, and thereby the driving force can be further improved.

[0018]

According to the first aspect of the invention, the first vibrating body including the first electromechanical conversion element and the vibrating plate in contact with the element is provided, and the stator and the stator are in contact with the outer peripheral portion of the vibrating plate. A second vibrating body that is connected to the second vibrating body and that vibrates the first vibrating body in a fixed direction; and a second vibrating body that is in contact with the vibrating plate through a fluid.
An electromechanical conversion element drive control means is provided which drives the first electromechanical conversion element to vibrate the first vibrating body and drives the second electromechanical conversion element in an appropriate phase with the first electromechanical conversion element. Therefore, the operating force can be further improved by the negative pressure action of the fluid, and the generation of the rotation moment can be effectively utilized by setting the contact portion between the rotor and the diaphragm to be the outer circumference and the inner circumference. Therefore, smoother rotation can be obtained, and further, by interposing a fluid between the rotor and the vibration plate, it is possible to prevent deterioration in durability due to wear or the like.

According to a second aspect of the present invention, the vibration plate and the rotor of the first vibrating body are formed in a disc shape, and their respective surfaces are brought into surface contact with each other, and the first electromechanical conversion element is driven so that the rotor and the surface are brought into contact with each other. Since the contact surface of the vibrating plate which comes into contact is displaced in a convex shape or a concave shape, such a disc-shaped flat structure can further reduce the thickness and size of the entire apparatus. It is a thing.

According to the third aspect of the invention, since the seal member for sealing the periphery of the fluid interposed in the contact portion between the vibration plate of the first vibrating body and the rotor is provided, the hermetically sealed state of the fluid is enhanced, Since the difference between the large and small restraint forces between the rotor and the rotor can be increased, the driving force can be further improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view of a drive mechanism that is a first embodiment of the present invention.

FIG. 2 is a plan view of a drive mechanism.

FIG. 3A is a state diagram showing a state in which the rotor is restrained when the diaphragm is convex, and FIG. 3B is a rotor restraint when the diaphragm is concave. It is a state diagram which shows a mode when it is large.

FIG. 4 is a vertical sectional side view showing a second embodiment of the present invention.

[Explanation of symbols]

 3a, 3b 2nd electromechanical conversion element 4 stator 5 2nd vibrating body 6 1st electromechanical conversion element 7 diaphragm 8 1st vibrating body 9 rotor 10 fluid 11 seal member

Claims (3)

[Claims] 1. A first vibrating body comprising a first electromechanical conversion element and a vibrating plate in contact with the element, a stator in contact with an outer peripheral portion of the vibrating plate, and the first vibrating body connected to the stator. A second vibrating body including a second electromechanical conversion element that vibrates in a fixed direction, a rotor that comes into contact with the vibrating plate via a fluid, and the first vibrating body that vibrates the first vibrating body by driving the first electromechanical conversion element. A drive mechanism characterized by comprising electromechanical conversion element drive control means for driving the second electromechanical conversion element at a proper phase with the first electromechanical conversion element. 2. The vibrating plate of the first vibrating body and the rotor are formed into a disc shape, and each surface of these is brought into surface contact, and the vibrating plate is brought into surface contact with the rotor by driving the first electromechanical conversion element. The drive mechanism according to claim 1, wherein the contact surface is displaced in a convex shape or a concave shape. 3. The drive mechanism according to claim 1, further comprising a seal member that seals around a fluid interposed in a contact portion between the vibration plate of the first vibrating body and the rotor.