JPH0642787B2 - Ultrasonic motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ultrasonic motor using ultrasonic vibration as a drive source.

2. Description of the Related Art An ultrasonic motor utilizing ultrasonic vibration includes a vibrating body serving as a drive source and a rotor provided above the vibrating body. By extracting an external force from the rotor provided on the upper portion, as a reaction thereof, the vibrating body receives a force in a direction opposite to the moving direction of the rotor.

The vibrating body of the ultrasonic motor is not in contact with other media in addition to the rotor for extracting the external force, because the energy escapes from the contact surface to the outside and the existence of the contact surface prevents vibration. Things are desirable. However, it is impossible to extract the force from the rotor unless the reaction force is prevented.

Conventionally, a material that does not hinder vibration, such as rubber or felt, is laid on the bottom of the vibrating body, and rotation is prevented by the frictional force between the felt and the vibrating body.

In general, the characteristics of an ultrasonic motor are characterized by low speed rotation and high torque, so the above fixing method is not sufficient, and a method of fixing with an adhesive such as silicone rubber has been adopted.

The above method has drawbacks such as low reliability, increased loss of the vibrating body, and inaccurate movement of the rotor. Therefore, improvement of the fixing method has been demanded.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention An object of the present invention is to improve a method for fixing a vibrating body in an ultrasonic motor so that a rotation angle of a rotor can be accurately determined without causing a vibration loss. .

Means for Solving the Problems In order to solve the above problems, an ultrasonic motor according to the present invention combines a vibrating body and a piezoelectric body to form a piezoelectric driving body, and the vibrating body is provided with the piezoelectric body. A plurality of grooves are formed on the surface opposite to the coupling surface with, and the piezoelectric driving body is excited by applying a voltage to the piezoelectric body, and is installed in contact with the groove forming surface of the vibrating body. In the ultrasonic motor for moving the moving body, the position of the piezoelectric driving body is fixed by inserting a pin or plate-shaped fixing means into the groove.

Action With the above-mentioned fixing structure, the pin contacts only a small part of the vibrating body, so it does not hinder the vibration of the vibrating body at all, and the position can be securely fixed in the circumferential direction. Is.

Embodiment FIG. 2 shows the basic structure of an ultrasonic motor. The vibrating body 1 in the figure is composed of a vibrating body main body 2 and a piezoelectric body 3, and a voltage is applied to the piezoelectric body 3 to vibrate the vibrating body 1 to serve as a driving force source. Further, the rotor 4 provided on the upper part of the vibrating body 1 is rotated left and right to take out the output from the shaft 4a. Further, a holder 5 (mechanical stator) for fixing the vibrating body 1 and the shaft 4a of the rotor 4 is provided.

As shown in detail in FIG. 1, a plurality of grooves 2a are provided in the upper portion of the vibrating body 1. By inserting the fixing plate 6a provided on the fixed body 6 into the groove, the rotation of the vibrating body 1 is stopped.
The fixed body 6 is fixed to the holder 5 shown in FIG. 2, for example.
The fixing plate 6a needs to be made of a material of the vibration main body 2, for example, a material having a property of being mechanically contradictory to metal or the like, for example, plastics, hard rubber, reinforced plastics or the like.
If it is made of metal or the like, the contact noise of vibration is large and contact vibration wear occurs. When the number of vibrating pieces is too large, the vibration of the vibrating body 1 is reduced, and therefore it is necessary to minimize the vibration. According to the experiment, it was possible to sufficiently prevent with four sheets.

It is also necessary to pay sufficient attention to the mechanical accuracy of the groove of the vibrating body 1 and the plate. When the gap is too large, the rotation accuracy of the rotor 4 is deteriorated, and when the gap accuracy is small, the rotor 4 contacts to reduce the efficiency of the vibrating body. Accuracy of 0.1 mm or less is required.

Here, the vibrating body 1 and the rotor 4 need to be pressed against each other. The pressing force is, for example, one of which is formed of a magnet and is magnetically coupled by a magnetic attraction force. Configure to obtain.

Further, it is not limited to the groove as shown in FIG. 1 and may be a hole as shown in FIG. In the configuration example of FIG. 3, the vibrating body 7 has a hole 7a.
Is provided, and a fixing pin (not shown) is inserted and fixed therein. The hole 7a is preferably provided on a so-called neutral surface 8 which does not extend or contract during vibration of the vibrating body.

In the above embodiment, the rotary type motor is shown, but the present invention is also applicable to a linear motor.

EFFECTS OF THE INVENTION By using the vibrating body fixing method according to the present invention, the vibrating body can be fixed without any hindrance to the vibration of the vibrating body, and thus without sacrificing the efficiency or stable operation of the motor. In terms of the motor configuration, the number of parts can be reduced, the reliability can be improved, and the rotation angle accuracy can be improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a main part of an ultrasonic motor according to an embodiment of the present invention, FIG. 2 is an exploded perspective view showing a configuration of the ultrasonic motor, and FIG. 3 is a perspective view of another embodiment of the present invention. Is. 1 ... Vibrating body, 2 ... Vibrating body, 2a ... Groove, 3 ...
Piezoelectric body, 4 ... Rotor, 5 ... Holder, 6 ... Fixed body,
6a: Fixed plate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-61-49672 (JP, A) JP-A-63-1378 (JP, A) JP-A 61-262091 (JP, A) JP-A 52- 52387 (JP, A)

Claims (3)

[Claims] 1. A vibrating body and a piezoelectric body are combined to form a piezoelectric driving body, and a plurality of grooves are formed on a surface of the vibrating body on a side opposite to a coupling surface with the piezoelectric body. An ultrasonic motor that excites the piezoelectric driving body by applying a voltage to the piezoelectric body to move a moving body that is in contact with the groove forming surface of the vibrating body, wherein the groove is a pin or a plate. The ultrasonic motor is characterized in that the position of the piezoelectric driving body is fixed by inserting the fixing means. 2. The ultrasonic motor according to claim 1, wherein the groove formed in the vibrating body is formed perpendicularly to the slip surface of the moving body which is in contact with the vibrating body. 3. The ultrasonic motor according to claim 1, wherein at least one of the vibrating body and the moving body is composed of a magnet, and the two are connected to each other by a magnetic coupling force.