JPH04331478A - Driving mechanism - Google Patents

Abstract

PURPOSE:To provide a driving mechanism for reducing the size and the thickness of device having enlarged application range. CONSTITUTION:First electromechanical converting elements 4a, 4b have one ends secured to a base 1 and the other ends coupled with a reciprocating oscillator 2 driving force thereof is transmitted to a mover 5 arranged in contact therewith. A drive control means for the electromechanical converting elements couples a second electromechanical converting element 6, reciprocating approximately in perpendicular to the oscillating direction of the oscillator 2, with the mover 5 and controls driving of the first electromechanical converting elements 4a, 4b and the second electromechanical converting element 6 with an appropriate phase.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive mechanism used in actuators, motors, paper feed mechanisms, and the like.

0002

[Prior Art] Taking an ultrasonic motor as an example of a conventional drive mechanism, its basic operating principle is to convert ultrasonic vibrations generated by a vibrator into one direction through the frictional force of a certain member. It is obtained by converting it into motion. In this case, the motion conversion in one direction is generally performed by vibration of an elliptical trajectory. Its elliptical motion is usually
It can be generated by generating a 'traveling wave' or by using 'two types of oscillators'.

[0003] An example of using two types of vibrators is disclosed in Japanese Patent Application Laid-open No. 121777/1983, for example. This device is constructed by integrating two piezoelectric torsional vibrators, a piezoelectric torsional vibrator and a piezoelectric thickness vibrator, into a cylindrical shape, and by applying a voltage to each piezoelectric element independently, it creates a torsional ellipse. This system generates motion and transmits the elliptical motion to the rotor to drive the motor.

[0004] Also, a drive principle similar to the above-mentioned example is described in the Proceedings of the Acoustical Society of Japan, p. 933,
H1 Oct. There are some disclosed. In this case, the rotor is sandwiched between a longitudinal vibrator (corresponding to the piezoelectric thickness vibrator described above) and a torsional vibrator (corresponding to the piezoelectric torsion vibrator described above), which are sandwiched.
The motor can be driven by transmitting the elliptical motion obtained by the combined displacement of the two vibrators to the rotor.

[0005]

[Problems to be Solved by the Invention] In recent years, flat type actuators have been required for OA equipment, especially for personal use, and thin actuators are indispensable.In addition, thin type actuators are required depending on the location, such as when installed in the door of a car. actuators may be required. However, in the conventional configuration as described above, the shape is elongated in the vertical direction, and the range of its application is severely limited.

[0006]

[Means for Solving the Problem] In the invention as set forth in claim 1, one end of the first electromechanical transducer is fixed on a base, and the other end of the first electromechanical transducer is vibrated in a reciprocating manner. a second electric machine, which is connected to the second electric machine, and has a movable body in contact with the vibrating body to which the driving force of the vibrating body is transmitted, and which reciprocates in a direction substantially perpendicular to the vibration direction of the vibrating body. An electromechanical transducer drive control means is provided which connects the transducer to the movable body and controls drive of the first electromechanical transducer and the second electromechanical transducer with appropriate phases.

The invention according to claim 2 is the invention according to claim 1, in which any two or all of the first electromechanical transducer, the vibrator, and the second electromechanical transducer are arranged in substantially the same plane. It was placed in

According to a third aspect of the invention, in the first aspect of the invention, magnetic force generating means is interposed between the vibrating body and the movable body.

[0009]

[Operation] In the invention as set forth in claim 1, the first electromechanical transducer element and the second electromechanical transducer element are driven and controlled with appropriate phases by the electromechanical transducer drive control means, so that the vibrating body and the movable body It is possible to create a difference in the frictional force generated at the contact surface between the vibrating body and the return path.
This makes it possible to rotate the moving body in the direction of stronger frictional force.

[0010] In the invention according to claim 2, by arranging any two or all of the first electromechanical transducer, the vibrating body, and the second electromechanical transducer in substantially the same plane, the size can be further reduced. This makes it possible to realize a flat drive mechanism.

In the third aspect of the invention, by interposing the magnetic force generating means between the vibrating body and the movable body, the frictional force between them can be further strengthened, thereby improving the generated torque. It becomes possible.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention as claimed in claim 1 will be explained based on FIGS. 1 and 2. A stator 2 as a vibrating body is provided on the base 1. Anchors 3a and 3b are provided at approximately symmetrical positions on the outer periphery of the base 1,
One ends of first piezoelectric elements 4a, 4b as first electromechanical transducers are fixed to these anchors 3a, 3b. The other ends of the first piezoelectric elements 4a, 4b are fixed to protrusions 2a, 2b formed on the outer surface of the stator 2. A rotor 5 as a moving body is provided above the stator 2 in contact with the stator 2.

Further, one end of a second piezoelectric element 6 as a second electromechanical transducer is fixed to the center of the base 1, and a shaft 7 is attached to the other end of the second piezoelectric element 6. It is fixed. A nut 8 is attached to one end of this shaft 7, one end of a spring 9 is connected to this nut 8, and the other end of the spring 9 is connected to the rotor 5, so that the spring 9 causes the rotor 5 to move downward. is energized. Therefore, the rotor 5 is
It is biased by a spring 9 from its upper surface side, and is pressed into contact with the second piezoelectric element 6 from its lower surface side.

Furthermore, here, the first piezoelectric element 4a
, 4b and the second piezoelectric element 6 with appropriate phases, a drive control circuit (not shown) is provided as an electromechanical transducer drive control means.

In such a configuration, when a voltage is applied to the first piezoelectric elements 4a, 4b by the drive control circuit to drive them, the first piezoelectric elements 4a, 4b generate an expansion/contraction movement. Due to this expansion and contraction movement, the stator 2 reciprocates in the plane direction about the shaft 7. In addition, by driving the second piezoelectric element 6 with an appropriate phase shift from the drive phase of the first piezoelectric elements 4a and 4b, the second piezoelectric element 6 is driven in the vertical direction (in a direction approximately perpendicular to the rotational direction of the rotor 5). Due to the expansion and contraction (reciprocating motion), a difference occurs in the frictional force between the contact surfaces between the stator 2 and the rotor 5 between the forward and backward paths of the stator 2, and this causes the rotor 5 to rotate in the direction where the frictional force is stronger. .

Furthermore, FIG. 3 shows an example in which a thrust bearing 10 is installed in the rotating part at the center of the rotor 5, which makes it possible to reduce the frictional force generated when the rotor 5 rotates. .

Next, an embodiment of the invention as claimed in claim 2 will be explained based on FIG. Note that the description of the same parts as those of the invention according to claim 1 described above (see FIGS. 1 and 2) will be omitted, and the same parts will be denoted by the same reference numerals.

In the embodiment described in claim 1 (see FIG. 1), the second piezoelectric element 6 is provided between the rotor 5 and the base 1, but here, the first piezoelectric elements 4a, 4b and Of the stator 2 and the second piezoelectric element 6, the first piezoelectric elements 4a, 4b and the stator 2 are arranged in substantially the same plane.

That is, the second piezoelectric element 6 is positioned above the rotor 5, the upper end of the second piezoelectric element 6 is fixed to the spacer 11 attached to the shaft 7, and the lower end of the second piezoelectric element 6 is fixed to the spacer 11 attached to the shaft 7. It is fixed to the rotor 5. In this case, the spacer 11 is connected to the spring 9 and biased downward, and the biasing force of the spacer 11 causes the second piezoelectric element 6 to move toward the rotor 5.
It is shaped like a pressed surface.

Therefore, by driving the second piezoelectric element 6 to perform reciprocating motion in the vertical direction, a difference is created in the frictional force between the contact surfaces of the stator 2 and the rotor 5, and this causes the rotor 5 to be moved by the frictional force. This makes it possible to rotate in the direction of the strongest force. In addition, in this case, the second piezoelectric element 6 is located above the rotor 5, and the first piezoelectric elements 4a, 4b and the stator 2 are set to be substantially in the same plane, resulting in a more compact and flat drive. It becomes possible to realize the mechanism.

Next, an embodiment of the invention according to claim 3 will be explained based on FIG. Note that the description of the same parts as those of the invention according to claim 1 described above (see FIGS. 1 and 2) will be omitted, and the same parts will be denoted by the same reference numerals.

[0022] Here, a permanent magnet 12 is interposed between the stator 2 and the rotor 5 as a magnetic force generating means. By providing this permanent magnet 12, the first
When the piezoelectric elements 4a, 4b and the second piezoelectric element 6 are driven, the ratio of the strength of the frictional force acting between the stator 2 and the rotor 5 can be further increased. It is possible to make it stronger.

FIG. 6 shows an example in which the various drive mechanisms described above are applied to a paper feeding mechanism. That is, by configuring the rotor 5 described above as the rotating roller 13, it becomes possible to convey the paper 14 between the rotating roller 13 and the stator 2. By making some simple modifications to the configuration of the drive mechanism in this way, its range of applications can be expanded.

[0024]

[Effects of the Invention] The invention as claimed in claim 1 is characterized in that one end of the first electromechanical transducer is fixed on a base, and a vibrating body that reciprocates is connected to the other end of the first electromechanical transducer. , a movable body to which the driving force of the vibrating body is transmitted is disposed in contact with the vibrating body, and a second electromechanical transducer that reciprocates in a direction substantially perpendicular to the vibration direction of the vibrating body. Since the electromechanical transducer drive control means is connected to the moving body and controls the driving of the first electromechanical transducer and the second electromechanical transducer with appropriate phases, the electromechanical transducer drive control means By controlling the drive of the first electromechanical transducer and the second electromechanical transducer with appropriate phases, the difference in the frictional force generated at the contact surface between the vibrating body and the moving body can be created between the forward and return paths of the vibrating body. This allows the moving body to rotate in the direction with stronger frictional force.

[0025] In the invention as claimed in claim 2, any two or all of the first electromechanical transducer, the vibrator, and the second electromechanical transducer are arranged in substantially the same plane, so that By arranging any two or all of them in substantially the same plane, it is possible to realize an even smaller and flatter drive mechanism.

[0026] The invention according to claim 3 is the invention according to claim 1, since a magnetic force generating means is interposed between the vibrating body and the movable body. By interposing the means, the frictional force between them can be further strengthened, thereby improving the generated torque.

[Brief explanation of drawings]

FIG. 1 is a side view showing a driving mechanism according to an embodiment of the invention.

FIG. 2 is a plan view of the drive mechanism of FIG. 1;

FIG. 3 is a side view showing an example in which a thrust bearing is inserted into the center of rotation of the rotor.

FIG. 4 is a side view showing an embodiment of the invention according to claim 2.

FIG. 5 is a side view showing an embodiment of the invention according to claim 3.

FIG. 6 is a side view showing an example in which the drive mechanism is applied to a paper feeding mechanism.

[Explanation of symbols]

1 Base 2 Vibrating bodies 4a, 4b First electromechanical transducer 5
mobile object

Claims (3)

[Claims] 1. A first electromechanical transducer having one end fixed on a base, a vibrating body connected to the other end of the first electromechanical transducing element and vibrating back and forth, and a vibrating body in contact with the vibrating body. a second electromechanical transducer connected to the movable body and reciprocating in a direction substantially perpendicular to the vibration direction of the vibrating body; A drive mechanism comprising an electromechanical transducer drive control means for driving and controlling the first electromechanical transducer and the second electromechanical transducer with appropriate phases. Claim 2: A first electromechanical transducer, a vibrator, and a second electromechanical transducer.
2. The drive mechanism according to claim 1, wherein any two or all of the electromechanical transducers are arranged in substantially the same plane. 3. The drive mechanism according to claim 1, further comprising magnetic force generating means interposed between the vibrating body and the movable body.