JPH0532994B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a mover of an ultrasonic motor useful as a drive device in various fields.

(Prior art and its problems) Various motor devices that apply electromagnetic force as a drive source have been widely used for various purposes.
However, these conventional motor devices have certain limitations in terms of size, weight reduction, and application fields.

This is also because it is restricted by the magnetic properties of the materials used.

On the other hand, as a motor device to replace these conventional motor devices, the present applicant has developed a motor device that uses ultrasonic vibration, that is, a vibration wave excited on the surface of an elastic body as an ultrasonic vibrator. A driving device has been proposed that converts this into a unidirectional motion of a moving object that presses into contact with this.

By converting the powerful vibrational energy of ultrasonic waves into rotational or linear motion, a small and lightweight motor device is realized.

However, although this ultrasonic motor device has attracted attention as having excellent features, there still remain specific issues that need to be further improved. For example, in general, the flatness of parts that have been cut or ground and pressurized has an error of about 0.001 mm to 0.1 mm. Even if they are brought into contact under pressure, the surface roughness of each part approximates the lateral amplitude a shown in Figure 1 from a microscopic perspective, making it impossible to contact them with uniform pressure, resulting in poor drive force transmission efficiency. The problem is that it is extremely damaged.

In addition, the amplitude of the vibration waves formed on the stator surface is not uniform, and even if machining accuracy is improved,
The movable element surface does not necessarily contact the vertices of all vibration waves.

Therefore, in order to maintain a predetermined transmission efficiency, it has been necessary to perform ultra-precision flat finishing on the stator surface along with the mover surface, but such finishing is difficult and has been difficult in terms of productivity and cost. It had become a drawback.

(Means for Solving the Problems) The present invention aims to solve the problems as described above, and as a means for that purpose, an ultrasonic motor having an elastic stator and a movable element is provided. The mover has a support body and a sliding body,
The present invention provides an ultrasonic motor in which the sliding body is disposed on the contact surface of the support with respect to the elastic stator and has a flange-like protruding piece.

Further, as an aspect of the present invention, there is provided an ultrasonic motor having an elastic stator and a movable element,
The mover has a support body and a sliding body, the sliding body is arranged on the contact surface of the support body with the elastic stator, and a cavity is formed between the sliding body and the support body. The ultrasonic motor and sliding body are
An ultrasonic motor is provided in which a plurality of flange-like protruding pieces are arranged in parallel.

The operating principle and embodiments of the motor device of the present invention will be described below with reference to the drawings.

(Function) FIG. 1 is a partially enlarged perspective view for explaining the principle of operation. Reference numeral 1 in the figure is a stator made of an elastic body such as metal, and the state in which a vibration wave, which is a combination of transverse vibration and longitudinal vibration, is formed on the stator surface 1a is shown in an enlarged manner.

Moreover, this FIG. 1 shows the propagation state of vibration waves (the vibration source is not shown). That is, if we focus on mass point B, it is moving in the direction of arrow M on an ellipse Q, which is a combination of transverse amplitude a (vertical direction) and longitudinal amplitude b (horizontal direction), and its vibration wave moves at the speed of sound U. is moving as a traveling wave. This movement is the same at any point on the stator surface 1a, and when the surface of the free movable element 2 is pressed into contact with the surface of the stator 1 under this condition, this movable element 2 The vibration waves of stator 1 are in contact only at the vertices A and A', and these vertices A and A' move in the direction of arrow M at a vibration velocity v = 2πfb (where f is the frequency). Therefore, the free movable element 2 is driven in the direction of the arrow N by the frictional force with the stator 1.

Therefore, in order to further increase the mechanical driving force (rotational force or propulsive force) of the mover 2 while keeping the electrical input constant, first increase the frictional force by increasing the contact pressure, and at the same time increase the number of peaks of the vibration wave. is brought into contact with the surface of the mover 2 with uniform pressure.

However, the surface of the movable element 2 receives high-frequency vibration pressure from the surface of the stator 1, and vibrational displacement occurs in the normal and tangential directions due to elastic deformation.
In particular, the vibration displacement in the tangential direction of the mover 2 is
This will greatly reduce the speed of

Therefore, the conditions that this mover 2 must meet are (1) to always follow the stator surface which has an imperfect plane, (2) to contact the peaks of non-uniform vibration waves with uniform pressure, (3) Part of the peak of the vibration wave (for example, about 1/8 to 1/8 of the wavelength)
(4) The elasticity should have sufficient responsiveness in the high frequency vibration band, (5) The modulus of elasticity in the normal direction of the moving element sliding body. (6) The vibration damping rate is small.

From this point of view, in this invention, the mover 2
is assumed to have a sliding body, and this sliding body, or in other words, a slider, satisfies the conditions that should be met as the movable element 2 and is integrated as the movable element.

(Example) Example 1 FIG. 2 shows an enlarged view of vibration waves formed on the surface of the stator 1. The movable element 2, which is integrally constituted by the support body 3 and the sliding body 4, is in pressure contact with the stator surface 1a.

Here, the meaning of "integrated" indicates that the sliding body 4 is brought into close contact with the stator surface 1a by the support body 3, and that sufficient responsiveness to elasticity within the high frequency vibration band is ensured.

The sliding body 4 is constructed by embedding high elastic modulus fibers 4b, such as piano wire, glass fiber, carbon fiber, etc., inside a low elastic modulus member 4a tangentially and along the traveling direction of vibration waves. However, the elastic modulus of the sliding body 4 itself is made to have anisotropy. In other words, the main components of the sliding body 4 are the low elastic modulus member 4a and the high elastic modulus fiber 4b.
The reason for selecting such components is that the low elastic modulus member 4a is used for vibration displacement in the normal direction caused by vibration pressure, and the high elastic modulus member 4a is used for vibration displacement in the tangential direction. This is to make the ratio fibers 4b correspond to each other.

The thickness and length of the sliding body 4 are determined so that the sliding body 4 can come into contact with a part of the peak of the vibration wave (for example, about 1/8 to 11/4 of the wavelength) by applying pressure.

Example 2 FIG. 3 also shows the vibration waves formed on the surface of the stator 1 in an enlarged manner. The movable element 2, which is integrally constituted by a support body 3 and a sliding body 4, is in pressurized contact with the stator surface 1a. Sliding body 4 in this case
shows an embodiment in which a high elastic modulus plate 4c, such as a metal plate, is fixedly supported on the surface of a low elastic modulus member 4a.

Example 3 FIG. 4 also shows the vibration waves formed on the surface of the stator 1 in an enlarged manner. A sliding body 4 having a flange-like protruding piece integrally formed with a support 3 made of metal or the like is in pressurized contact with the stator surface 1a. This sliding body 4 has flexibility in the direction normal to the stator surface 1a, and is designed so that it can come into contact with a part of the peak of the vibration wave (for example, about 1/8 to 1/4 of the wavelength). The thickness t and length l of the sliding body 4 are determined. Further, the natural frequency of the sliding body 4 needs to be higher than the drive frequency of the stator 1, and the ratio of the thickness and length of the sliding body 4 must be taken into consideration.

Embodiment 4 FIG. 5 shows a cross-sectional view of a sliding body 4 having a hollow portion formed of an arcuate plate member fixedly supported by a support body 3. As shown in FIG. This sliding body 4 also has the same properties as the embodiment shown in FIG.

Embodiment 5 FIG. 6 shows a cross-sectional view of a sliding body having a plurality of flange-like protruding pieces shown in FIG. 4.

In particular, in FIGS. 4 and 6, the sliding body 4
The tip of the stator is close to a line contact, and if the direction of contact and the direction of movement are the same, a specific location on the stator surface 1a will wear out.

Therefore, by making the contact direction oblique with respect to the moving direction, the stator surface can be evenly contacted. In the case of a rotary movable element, it can be constructed by forming non-concentric circles.

(Effects of the Invention) As explained above, this invention achieves high efficiency by employing a movable element that contacts the stator surface having an imperfect plane with uniform pressure, and generates even stronger driving force. It is possible to plan for occurrence.

Furthermore, the flat surface machining accuracy of the stator surface does not require ultra-precision machining, general machining conditions are sufficient, and a large cost burden can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged perspective view showing the operating principle of the ultrasonic motor of the present invention, and FIGS. 2 to 6 are
FIG. 1 is an enlarged perspective view showing an embodiment of the invention. B...Mass point, a...Transverse amplitude, b...Longitudinal amplitude, Q
...ellipse, M...direction, U...sonic speed,
A, A'... Vertex, N... Direction, 1... Stator,
1a... Stator surface, 2... Mover, 3... Support body, 4... Sliding body, 4a... Low elastic modulus member, 4b
...High elastic modulus fiber, 4c...High elastic modulus board.

Claims (1)

[Claims] 1. An ultrasonic motor having an elastic stator 1 and a movable element 2, the movable element 2 having a support body 3 and a sliding body 4.
an ultrasonic motor, wherein the sliding body 4 is disposed on the contact surface of the support body 3 with respect to the elastic body stator 1. 2 An ultrasonic motor having an elastic stator 1 and a movable element 2, in which the movable element 2 has a support body 3 and a sliding body 4.
The sliding body 4 is arranged on the contact surface of the support body 3 with respect to the elastic body stator 1, and the sliding body 4 has:
The ultrasonic motor according to claim 1, which has a cavity. 3 An ultrasonic motor having an elastic stator 1 and a movable element 2, the movable element 2 having a support body 3 and a sliding body 4.
The sliding body 4 is arranged on the contact surface of the support body 3 with respect to the elastic body stator 1, and the sliding body 4 has
The ultrasonic motor according to claim 1, wherein the ultrasonic motor has a flange-like projecting piece.