JPH02250677A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To utilize vibration energy of an ultrasonic vibration body efficiently by driving two moving bodies in contact with the opposite faces of the ultrasonic vibration body with traveling wave excited on the opposite faces of the ultrasonic vibration body. CONSTITUTION:When a moving body 7 is driven in the direction L and a moving body 8 is driven in the direction R, central shaft 7' rotates counterclockwise and central shaft 8' rotates clockwise. Consequently, rolling bodies 9, 9, 9, 9 revolves counterclockwise. Assuming any one of the central shafts 7', 8' of the moving bodies 7, 8 is the output shaft to an external device, the rolling bodies 9, 9, 9, 9 transmit the driving force of the moving body 8 or 7 which is not the output shaft to the moving body 7 or 8 having the output shaft so that the moving bodies 7, 8 have same rotation. Since the load on the moving body having the output shaft is also applied onto the moving body which has not the output shaft, load to be applied onto the moving body having the output shaft can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic motor using a piezoelectric element or a magnetostrictive element as a drive ratio.

[Conventional technology]

As a conventional ultrasonic motor, for example, JP-A-58-1486
There is a technique disclosed in Japanese Patent Application Laid-Open No. 60-183982. This ultrasonic motor drives a moving body by a traveling wave generated by an ultrasonic vibrating body that is constructed by combining a plurality of piezoelectric elements or magnetostrictive elements and incorporating them into an elastic body. A conventional cylindrical ultrasonic motor has a central axis erected on one side of an annular moving body, and the other side is in contact with one side of an annular ultrasonic vibrating body. The vibration energy generated is converted into rotational motion of the moving body.

FIG. 4 is a diagram showing the operating principle of a conventional ultrasonic motor having the above-described configuration, and shows the relationship between the ultrasonic vibrating body 1 and the movable body 2.

The ultrasonic vibrating body 1 has a configuration in which a plurality of piezoelectric elements are incorporated in an elastic body, and when a high frequency voltage is applied to each of the incorporated piezoelectric elements with a phase shift, each piezoelectric element is distorted. The ultrasonic vibrating body 1 as a whole performs bending vibration. Although longitudinal waves and transverse waves exist independently in the ultrasonic vibrator 1, the longitudinal waves and transverse waves intertwine with each other to form a traveling wave, which causes the bending vibration. The apex of the traveling wave comes into contact with the vibrating body 2 on one surface 1' of the ultrasonic vibrating body 1, but if we focus on certain points A and A' on the line corresponding to the apex part of this traveling wave, the points A and A' are Performs elliptical motion.

Assuming that the contact points A and A' are moving in the direction of arrow M in the figure, the moving body 2 is driven in the direction of M of the ellipse Q at the contact points A and A', that is, in the direction of arrow N in the figure.

[Problem to be solved by the invention]

However, in the conventional ultrasonic motor, since the moving body is in contact with only one surface of the ultrasonic vibrator, there is a problem in that only the traveling waves generated on one surface of the ultrasonic vibrator are utilized. In other words, as the ultrasonic vibrator undergoes bending vibration, traveling waves are generated on the other side as well as on one side.
The energy of the traveling waves generated on the other side is not utilized.

The present invention has been made to solve such problems, and provides an ultrasonic wave that can efficiently utilize the vibration energy of the ultrasonic vibrator by bringing a moving body into contact with both sides of the ultrasonic vibrator. The purpose is to provide motors.

[Means to solve the problem]

The ultrasonic motor of the present invention is an ultrasonic motor that is configured to contact one surface of an ultrasonic vibrating body and drive a moving body having a central axis with the ultrasonic vibrating body. The body is in contact with the other surface of the ultrasonic vibrating body, the central axis of one moving body is hollow and the central axis of the other moving body is loosely inserted, and the central axis of one moving body is loosely inserted into the gap between the two central axes. A rolling element is provided around the periphery, and the two movable bodies are configured to mutually transmit driving force via the rolling element.

[Effect]

The ultrasonic motor of the present invention drives two movable bodies that are in contact with both sides of an ultrasonic vibrator by traveling waves excited on each side of the ultrasonic vibrator. Since the traveling directions of the traveling waves are opposite to each other, the two moving bodies rotate in opposite directions. When two moving objects rotate in opposite directions, 2
The rolling elements interposed between the central axes of the two moving bodies rotate, and the two
Two moving bodies mutually transmit driving force. Therefore, when the central axis of one moving body is used as the output shaft to an external device, the rolling elements transmit the driving force of the moving body that is not the output shaft to the moving body that has the output shaft, and the rotational speed of the two moving bodies is are the same.

〔Example〕

The present invention will be explained below based on the drawings showing one embodiment thereof.

FIG. 1 is a sectional view of the ultrasonic motor of the present invention.

In the figure, 3 is an ultrasonic vibrator. The ultrasonic vibrator 3 is made by arranging a plurality of piezoelectric elements 6 in the shape of a 174 ring or 1/8 ring in an annular shape, and sandwiching the piezoelectric elements 6 between annular elastic bodies 4 and 5. A movable body 7 in which central shafts 7'8' are integrated on both upper and lower surfaces of the ultrasonic vibrating body 3 having such a configuration.
8 are in contact.

The movable body 7 that is in contact with the upper surface of the ultrasonic vibrator 3 has approximately the same shape as the ultrasonic vibrator 3, and has a cylindrical central axis 7' on the side that is not in contact with the ultrasonic vibrator 3. has been erected. On the other hand, the movable body 8 that is in contact with the lower surface of the ultrasonic vibrator 3 is circular with a central axis 8', and the central axis 8' is the ultrasonic vibrator on the side that is in contact with the ultrasonic vibrator 3. 3 and the center shaft 7'. The ultrasonic vibrator 3 and the movable body 7.8 having the above-mentioned configurations have a central axis 8' that is erected on the side of the movable body 8 that is not in contact with the ultrasonic vibrator 3.
is housed in the casing 11 so as to be supported by a bearing (not shown) on the bottom of a cylindrical casing 11 with a bottom. By screwing into the casing 11, the casing 1
The top opening of No. 1 is closed. Springs 10a, 10b, and 10c are provided between the bottom surface of the casing 11 and the movable body 8 and between the lid body 12 and the movable body 7.

10d is arranged so as to urge the movable bodies 7 and 8 toward the ultrasonic vibrating body 3, whereby the movable bodies 7.8
is in pressure contact with the ultrasonic vibrator 3.

Further, as shown in FIG. 2, a plurality of cylindrical rolling elements 9, 9.9 are disposed around the gap between the central shafts 7' and 8'. The rolling elements 9.9, 9.9 have appropriate friction coefficients, and each rolling element 9, 9.9.9 has a central axis? Although it rotates along with the rotation of ', 8', it has a structure that cannot revolve around the central axis 8'.

FIG. 3 is a diagram showing the operating principle of the ultrasonic motor of the present invention.

In the figure, as described in the configuration of FIG. 1, the ultrasonic vibrator 3
A moving body 7 is in contact with one surface 3a, and a moving body 8 is in contact with the other surface 3b. When a voltage is applied to the piezoelectric element 6 of the ultrasonic vibrating body 3, a traveling wave is generated, and the moving bodies 7 and 8 contact points A and A' with the ultrasonic vibrating body 3.
and B move in an ellipse. As shown in the figure, since the ellipses move in the same direction, the movable body 7 and the movable body 8 are driven in opposite directions, that is, in the directions of arrows A and R in the figure.

In order to utilize the driving force of the movable bodies 7 and 8 that are driven in opposite directions, the ultrasonic motor of the present invention has the configuration as explained in FIG. 1.

That is, in this ultrasonic motor, the center shaft 8' of the moving body 8 is loosely inserted into the center axis 7' of the moving body 7, and the rolling elements 9, 9, 9, 9 are inserted in the gap between the center shafts 7' and 8'. It has an intervening configuration.

The action of the rolling elements will be explained by taking as an example the case where the moving bodies 7 and 8 are each driven in the R direction. When the moving body 7 is driven in the L direction and the moving body 8 is driven in the R direction, the second
As shown in the figure, the central axis 7' rotates counterclockwise, and the central axis 8
' rotates clockwise.

When the central shafts 7' and 8' rotate in opposite directions, the rolling elements 9
, 9, 9.9 all rotate in the same direction as the central axis 7', that is, counterclockwise. Therefore, if the central axis 7' or 8' of either the moving body 7 or the moving body 8 is used as the output shaft to the external device, the rolling elements 9.9°9.9 will rotate the two moving bodies 7.8. In order to make the numbers the same, the driving force of the movable body 8 or movable body 7 that does not have an output shaft is transmitted to the movable body 7 or movable body 8 that has an output shaft. In other words, the load of the movable body having the output shaft is also applied to the movable body having no output shaft via the rolling elements, and as a result, the load applied to the movable body having the output shaft is reduced.

In this embodiment, a cylindrical ultrasonic motor has been described, but the present invention is not limited to this, and the same effect can be obtained by adopting a similar structure for an annular ultrasonic motor.

〔Effect of the invention〕

As explained above, the ultrasonic motor of the present invention has high energy utilization efficiency because it utilizes the energy of traveling waves on both sides generated in the ultrasonic vibrator that is the drive source of the ultrasonic motor.

Furthermore, since the ultrasonic motor of the present invention is configured so that the driving forces of the two moving bodies can be mutually transmitted, the load of one of the moving bodies can be borne by the driving forces of both moving bodies.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the ultrasonic motor of the present invention, Fig. 2 is an enlarged top view of the ultrasonic motor of the present invention, Fig. 3 is a diagram showing the operating principle of the ultrasonic motor of the present embodiment, and Fig. 4 1 is a diagram showing the operating principle of a conventional ultrasonic motor. 3... Ultrasonic vibrating body 4.5... Elastic body 7.8...
・Mobile object? ', 8'...Central axis 9...Rolling element patent Applicant Sanyo Electric Co., Ltd. Agent Patent attorney Noboru Kono Funeral map

Claims (1)

[Claims] 1. In an ultrasonic motor that is in contact with one surface of an ultrasonic vibrating body and configured to drive a moving body having a central axis with the ultrasonic vibrating body, another moving body having a central axis is connected to the ultrasonic vibrating body. The central shaft of one moving body is hollow and loosely inserts the central shaft of the other moving body, and rolling elements are disposed around the gap between the two central shafts. An ultrasonic motor characterized in that two moving bodies are configured to mutually transmit driving force via rolling elements.