JPS61102177A - Surface wave drive motor - Google Patents

Abstract

PURPOSE:To enhance the efficiency and to generate a strong drive force by forming the surface of the side contacted with the stator of a driven unit of an elastic material for exciting a surface wave. CONSTITUTION:When a high frequency voltage is applied to a piezoelectric unit 32 secured to one end of a stator 31 made of an elastic material, the stator 31 is bent and vibrated to generate a surface wave on the surface contacted with a rotor 33. The rotor 33 formed of the elastic material integrally with a slider 34 is affected by the vibrating pressure of the surface wave to generate the surface wave by the bending vibration having coaxial vibrating frequency and sonic velocity. The rotor 33 is driven in the prescribed direction by the frictional force with the stator 31.

Description

[Detailed description of the invention] The present invention relates to a surface wave drive motor.

Most of the various motor devices that have been widely used in the past utilize electromagnetic force as their driving source, and are used for various purposes.

However, the size, weight, rotational force, etc. of these devices are subject to certain limitations depending on the materials used.

This is because these factors are determined by the magnetic properties of the materials used, and devices exceeding these properties cannot be rotated.

On the other hand, as an alternative to these various motor devices, the present applicant has developed a motor device that uses ultrasonic vibration, that is, a motor device that is placed in a position where the surface waves excited on the surface of an ultrasonic vibrator come into pressure contact with each other. A device for converting a moving body into unidirectional motion has been disclosed.

These inventions have realized a compact and lightweight motor device by converting the powerful vibrational energy of ultrasonic waves into rotational or linear motion.

Conventionally, the surface of the rotor/translator of a surface wave motor in contact with the stator has been made rigid enough not to deform even when subjected to vibration pressure from the stator, and in order to obtain strong driving force, the surface has been It was via a slider made of a rubber-like elastic body with high elasticity and a high coefficient of friction. This type of motor had a large energy loss in the slider, resulting in a significant decrease in motor efficiency.

Therefore, in the present invention, by giving appropriate elasticity to the surface of the rotor/scillator that contacts the stator and generating surface waves on that surface, the slider can be made extremely thin and highly efficient. It is an object of the present invention to provide a surface wave drive motor as described above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The operating principle and embodiments of the motor device according to the present invention will be described in detail below with reference to the drawings.

1) Principle of operation FIG. 1 is a partially enlarged perspective view for explaining the principle of operation. Reference numeral 1 indicates an elastic body such as a metal, and the state in which a surface wave, which is a combination of transverse vibration and longitudinal vibration, is generated on the surface la of the elastic body is shown in an enlarged manner.

FIG. 1 shows only the propagation state of surface waves (the vibration source is not shown). That is, when focusing on mass point B, an ellipse Q is a composite of lateral width a (vertical direction) and longitudinal width b (horizontal direction).
is moving in the direction of arrow M above, and its surface wave has a speed of sound U
is moving at a speed of

This movement is the same at any point on the surface la, and when the surface of the free moving body 2 is brought into pressure contact with the surface of the elastic body 1 under this condition, the moving body 2 moves onto the surface of the elastic body 1. Since the waves are in contact only at their peaks A and A1, and these peaks A and A' are moving in the direction of arrow M at a vibration velocity of V = 2Xfb (where f is the frequency), it is free. The moving body 2 is driven in the direction of arrow N by the frictional force with the elastic body 1.

Therefore, in order to further increase the mechanical driving force (rotational force or propulsive force) of the moving body 2 while keeping the electrical input to the vibrator constant, first increase the frictional force by increasing the contact pressure and contact area, and at the same time It is necessary for many vertices of the object to be in contact with the surface of the moving object with uniform pressure.

In addition, the surface of the moving body receives high-frequency vibration pressure from the surface of the elastic body 1, and vibration displacement occurs due to elastic deformation in the normal and tangential directions.In particular, the vibration displacement in the tangential direction of the moving body 2' This will greatly reduce the speed.

From this point of view, the present invention provides a moving body 2B (corresponding to a rotor/mover) with appropriate elasticity as shown in FIG.
A surface wave B is generated on a surface in contact with an elastic body IA (corresponding to a stator).

In FIG. 2, the surface of a moving object 2B generating surface waves B is pressed into contact with the surface of an elastic body IA so that the peaks of surface waves A and the troughs of surface waves B face each other.

At this time, the transverse amplitude a' of the surface wave B is the transverse amplitude a of the surface wave A.
If we keep it smaller, that is, focus on mass point C, the elastic body moves in the direction of arrow M on an ellipse Q, which is a combination of transverse amplitude a (vertical direction) and vertical vibration @b (horizontal direction). The moving body is moving in the direction of arrow M' on an ellipse Q' which is a combination of transverse amplitude a+ and longitudinal amplitude b1. Surface waves A and B are moving at the speed of sound U.

Since the moving body 2B is in contact with the elastic body IA only at the peak of the surface wave A, the moving body 2B is driven in the direction of the arrow N by the frictional force with the elastic body.

The velocity V of the moving object at this time is V=2 π f(b+b') (However, f is the frequency of vibration) It is.

Due to this operating principle, the concave surface of the moving body and the convex surface of the elastic body come into contact, resulting in a wide contact area, and it is possible to improve wear resistance by increasing frictional force and decreasing surface pressure.

Further, a slider having a high friction coefficient may be interposed between the moving body and the elastic body, and it is effective even if the thickness thereof is sufficiently thin. Note that the velocity of the moving body V is 2 due to the presence of the surface wave B.
A speed increase of πf b' can be obtained, making it possible to improve transmission efficiency.

2) Regarding the generation of surface waves B One possible method for generating surface waves B in a moving body (equivalent to a rotor) is to use a vibrator to excite the moving body itself, but surface waves on an elastic body (equivalent to a stator) It is necessary to synchronize with A, making the circuit on the power supply side complicated. Therefore, surface waves of elastic bodies are generally used.

One possible method is to use the vibration pressure caused by A to excite a moving body.

FIG. 3 shows an embodiment of a surface wave drive motor.

When a high frequency voltage is applied to the piezoelectric body 32 fixed to one end surface of the stator 31, the stator 31 generates bending vibration and generates a surface wave A on the surface in contact with the rotor.

The rotor 33 integrally formed with the slider 34 has a surface wave A
, generates a surface wave B due to bending vibration having the same frequency and sound speed. At this time, the inherent sound speed of the surface wave B generated in the rotor must not be the same as the sound speed of the surface wave A.

This is because the rotor resonates due to the surface wave A, and the surface wave A
This is because the amplitudes of the surface waves B and B are the same, and as is clear from the principle of operation, they are not converted into unidirectional motion.

3) Effects of the invention As explained above, the present invention provides a rotor/mover with appropriate elasticity and generates surface waves on the surface in contact with the stator, thereby achieving high efficiency and further strengthening. This is extremely useful in terms of generating driving force. Furthermore, it is an extremely useful invention that has the secondary effect of improving durability by reducing contact surface pressure and reducing weight.

[Brief explanation of drawings]

Fig. 1 is a partially enlarged perspective view of the operating principle of a conventional surface wave drive motor, Fig. 2 is a partially enlarged perspective view of the operating principle of the present invention, and Fig. 3 is an explanatory diagram showing an embodiment of the present invention. be. 1...Elastic body (stator). ? ...Moving object (rotor/mover). Patent applicant Shinsei Kogyo Co., Ltd. Representative Finger 1) Grader Figure 1 Figure 2 Figure 3 Figure 137 3b

Claims (1)

[Claims] 1 In a surface wave drive motor consisting of a stator equipped with an ultrasonic vibrator that oscillates surface waves A and a driven body that rotates or moves in contact with this stator, the side of the driven body in contact with the stator A surface wave drive motor characterized in that a surface is formed of an elastic member that excites a surface wave B.