JPH01270774A - Linear ultrasonic motor - Google Patents

Abstract

PURPOSE:To easily move a bent passage by bringing a second member into contact with a first member at two positions aligned in a direction different from a moving direction, and independently varying a driving speed generated at the contact part. CONSTITUTION:A linear ultrasonic motor 10 has a moving element 11 corresponding to a second member, and rod-like piezoelectric elements 13a-13d of slip mode capable of vibrating on the upper and lower surfaces of a piezoelectric element 12 of a thickness mode capable of vibrating are provided in parallel. Electrodes are disposed in insulation on the upper and lower surfaces 9a, 9b of the first-second piezoelectric elements 12-13, and exciting means is formed of the elements 12-13. A pair of vibrators 14a-14b are so disposed as to hold the elements 12-13 from above and below, and clamped by bolts 15. Further, stationary rails 17a-17b are slidably interposed between the blades of the vibrator 14. Thus, it is moved in a predetermined direction by elliptical vibration generated at two contacts to vary its relative moving direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention relates to a near-return sound wave motor that utilizes a standing wave with a substantially elliptical orbit.

(Prior Art 1) A conventional linear ultrasonic motor (described in Japanese Unexamined Patent Application Publication Nos. 60-62881 and 61-218376) uses an electrostrictive element or a magnetostrictive element to generate approximately elliptical vibration on two rails made of an elastic body. A method has been adopted in which the nearly elliptical vibration causes a slider that is brought into pressurized contact with the rail to move linearly along the rail.

[Problems to be Solved by the Invention] However, the conventional linear ultrasonic motor only moves the movable element linearly; It was not possible to move the mover along a curved path.

This is because the driving force generated by the substantially elliptical vibration is a high torque, and therefore the speed difference caused by the distance difference between the inner circumference and the outer circumference at the curved portion cannot be absorbed as friction.

However, as the field of use of linear motors expands, it is desired to realize a linear ultrasonic motor that has the advantages of linear ultrasonic motors such as high torque and can move a slider along a curved path. It is rare.

The present invention has been made to solve the above problems,
The purpose is to provide a linear ultrasonic motor capable of moving a slider along a curved path.

[Means for Solving the Problems 1--In order to achieve the object described above, the present invention includes a member of zi,
a second member in contact with the first member; and an excitation means for exciting approximately elliptical vibration in a contact portion of the second member with the first member, and is excited by the m-oscillation means. In a linear ultrasonic motor that relatively moves the first member and the second member even by using a driving force generated by substantially elliptical vibration, the second member moves in a direction different from the moving direction. It is characterized in that it is in contact with the first member at at least two locations in a row, and that the drive speed generated by substantially elliptical vibrations at the two contact portions can be independently changed.

L Effect] In the present invention having the above configuration, the first member and the second member are driven by substantially elliptical vibrations generated at the two contact portions and move in a predetermined direction.

At this time, if the driving speeds at the two contact portions are not uniform, the direction of relative movement will change.

[Example] Example #41 embodying the present invention will be described below with reference to FIGS. 1 to 4.

The mover 11 corresponding to the second member in the linear ultrasonic motor 10 of this embodiment will be explained with reference to FIGS. 2 and 3. A thickness mode piezoelectric element (hereinafter referred to as the first piezoelectric element) 1 that can vibrate in the direction of arrow A in FIG.
On the upper and lower surfaces of 2, horizontal mode rod-shaped piezoelectric elements (hereinafter referred to as second piezoelectric elements) 13& to 13d that can vibrate in the direction of arrow B in FIG. 2 are arranged side by side. On each of the upper and lower surfaces 9a and 9b of the first piezoelectric element 12 and the piezoelectric elements 13a to 13d of tpJ2,
Electrodes (not shown) are arranged to be insulated from each other. These first and second piezoelectric elements constitute excitation means. A pair of vibrating bodies 14a and 14b are arranged between the first and second piezoelectric elements from above and below. These members are the vibrating body 14a.

It is fixed with a bolt 15 and a nut 16 through a through hole provided in n4b and the first piezoelectric element 12.

Next, the overall configuration of the linear ultrasonic motor 10 using this mover 11 will be explained using FIG. 3. A protrusion 11a is provided at the center of the lower surface of the movable element 11, and the protrusion 11a is slidably engaged with [18] provided on the base along the moving path of the movable element 11, as shown in FIG. are combined. Further, the vibrating body 14a provided above and below the movable element 11,
A fixed rail 1 corresponding to the first member is attached to the wing portion of 14b.
7a.

17b is slidably sandwiched.

The operation of the linear ultrasonic motor 10 configured as above will be explained below.

When an alternating current voltage is applied to electrodes (not shown) attached to the upper and lower surfaces of the first piezoelectric element 12 of the mover 11, the wing portions of the vibrating bodies 14a, 14b will generate vibrations in the direction of arrow A in FIG. A standing wave that vibrates in bending is generated. Further, when an AC voltage is applied to the electrodes (not shown) of the second piezoelectric elements 13a to 13d, a standing wave of shear vibration in the direction of arrow B in FIG. 2 is generated in the wing portions of the vibrating bodies 14a and 14b. . FIG. 4 shows the shape of the vibrating body 14a at the maximum displacement in the standing wave of the second shear vibration, and the i-moving body 14a, which has the shape shown by the solid line in steady state, deforms into the shape shown by the broken line at the maximum displacement. do. As can be seen from this figure, in this vibration mode, the amplitude in the direction of arrow B is larger toward the ends and smaller in the center.
By applying an alternating current voltage having a predetermined frequency to each electrode of the piezoelectric elements 13a to 13d and causing the vibrating bodies 14a and 14b to resonate, the vibrations in the directions of the arrows A and B are synthesized to create a substantially circular oscillation. It becomes a vibration. Therefore, the fixed rail 17a is inserted between the vibrating bodies 14a and 14b.

17b, a driving force is generated in a predetermined direction. This driving force is applied to the fixed rail 17a of the vibrating body 14m+14b.
, 17b is approximately proportional to the maximum amplitude of the approximately elliptical vibration in the direction of arrow A in FIG. 2. Therefore, as described above, the vibrating bodies 14m and 14b have a large maximum amplitude at the ends, so that the more the fixed rails 17a and 17b are sandwiched at the i portion of the vibrating bodies 14a and 14b, the higher the driving speed is, and vice versa. The drive speed is smaller as it is sandwiched closer to the center, so for example on the right side? When moving along the WIftl path, as shown in FIG. 1, the fixed rail 17a is curved so that the right fixed rail 17a at the curved portion abuts on the inside of the vibrating bodies 14a, 14b. Then, the driving speed acting on the right side of the moving element 10 becomes smaller than the driving speed acting on the left side, and the moving element 10 attempts to rotate to the right. Therefore, the mover 10 can be moved along the curved path without difficulty. In the case where the mover 10 is moved along a path curved to the left, the left fixed rail 17b is similarly curved.

Further, as shown in FIG. 5, both left and right fixed rails 17a, 1
If 7b is curved in contrast, the speed of the moving element 11 can be changed without adjusting the AC voltage.

Next, a method of changing the moving direction and speed of the movable element by changing the thickness of the fixed rail will be described as a second embodiment with reference to FIG. 6. The mover 11 in this second embodiment has the same configuration as the mover in the vJl embodiment, and as described above, the fixed rails 17c, 17d
It is in contact with When moving this movable element 11 along a path curving to the left, the right fixed rail 17d at the curved portion is made thicker, and the vibrating bodies 14a, 14b of the movable element 11 and the right side fixed rail 17d are made thicker at the curved part. The contact area with the rail 17d is increased. Generally, if it is approximated that the substantially elliptical vibrations in the vibrating bodies 14a, 14b of the mover 11 are uniform, the driving force acting between the vibrating bodies 14a, 14b and the fixed rails 17c, 17d in contact with each other will be approximately equal to the contact area. Proportional. Therefore, in this case, the driving speed on the right side of the moving element 11 is higher than the driving speed on the left side, and as a result, the moving element rotates to the left. In addition, when changing the speed, both left and right fixed rails 17c, 17
The contact area with d is changed at the same ratio.

Next, a third embodiment of the present invention will be described.

7 to 9 are explanatory diagrams of a standing wave type linear ultrasonic motor as a third embodiment.

First, the configuration of the mover 20 in this embodiment will be explained with reference to FIG.

Slip oscillators 22 are arranged on both the upper and lower surfaces of the thickness oscillator 21. Electrodes (not shown) that are insulated from each other are arranged on the upper and lower surfaces of these vibrators. A vibrating body 23 is crimped on the upper and lower surfaces of the sliding vibrator 22 so as to sandwich the thickness vibrator 21 and the sliding vibrator 22! (not shown) and constitutes the first excitation 1!524. In addition, thin oscillators 26 are arranged on both upper and lower surfaces of the thickness oscillator 25. A vibrating body 27 is crimped by crimping means (not shown) on the upper and lower surfaces of the sliding oscillator 26 so as to sandwich the thickness oscillator 25 and the sliding oscillator 26, and constitutes a second excitation section 28. There is. The first excitation section 24 and the second excitation section 28 are integrated via the fixing section 29 to form the mover 20.

Moreover, as shown in FIGS. 8 and 9, each electrode of the first excitation section 24 has ! Eleven control means 30 are connected, and a first rail 32 is clamped. Moreover, each ? of the second excitation section 28? ! ! A second control means 31 is connected to the pole,
Also, a #42 rail 33 is sandwiched. The thickness vibrators 21 and 25 are made of thickness mode piezoelectric elements,
The sliding vibrators 22 and 26 are made of sliding mode piezoelectric elements.

The linear ultrasonic motor configured as described above controls the thickness oscillator 21 and the slip oscillator 2 by the first control means 30.
By applying an alternating current electric signal to the rail 2, a substantially elliptical motion is excited on the crimped surfaces of the vibrating body 23 and the rail 32. At the same time, the second control means 31 applies an AC electric signal to the thickness oscillator 25 and the sliding oscillator 26, so that the vibrating body 27
A substantially elliptical motion is excited on the crimp surface between the rail 33 and the rail 33. As a result, the slider 20 moves on the rails 32,33.

Since the approximately elliptical motion excited by the first excitation section 24 and the second excitation section 28 can be controlled independently, if the rails 32 and 33 have an arbitrary curvature, the approximately elliptical motion according to the curvature can be controlled independently. By adjusting the amplitude and phase of the AC electric signals applied from the first control means 30 and the second control means 31 so that the movable element 20 is excited, it becomes possible to move the movable element 20 on the rails 32 and 33. .

Further, as shown in FIG. 10, a curvature sensor 34 that senses the curvature of the rail 32, 33 is added to the mover 20, and an AC electric signal corresponding to the curvature sensed by the curvature sensor 34 is sent to the first excitation section 24 and If the voltage is applied to the second excitation section 28, it becomes possible to automatically move on the rails 32, 33 having an arbitrary curvature.

Moreover, it is also possible to modify the above embodiment as follows. Although a thickness mode piezoelectric element and a berry mode piezoelectric element were used to excite approximately elliptical vibration in the vibrating body, any excitation method may be used as long as approximately elliptical motion is excited in a predetermined portion of the vibrating body. Further, in this embodiment, a piezoelectric element is used for excitation, but other electromechanical transducer elements such as an electrostrictive element or a magnetostrictive element can also be used.

[Effects of the Invention] As is clear from the detailed description above, the present invention has the feature that the first and second members can be moved relatively easily along a curved path. .

Therefore, there is an effect that the linear ultrasonic motor can be used even in fields where it could not be used in the past.

[Brief explanation of the drawing]

1 to 10 show embodiments of the present invention.
IS1 is a top view of the linear ultrasonic motor 10 of the first embodiment, FIG. 2 is an exploded perspective view of the mover 11 in the linear ultrasonic motor 10, and FIG. 3 is a perspective view of the linear ultrasonic motor 10. , FIG. 4 is a top view showing the state of vibration of the vibrating body in the mover 11, FIG. tJS5 is a top view of a linear ultrasonic motor as a modification of the first embodiment, and FIG. FIG. 7 is a top view of the linear ultrasonic motor 20 of the third embodiment, and FIG.
8 is a top view of the linear ultrasonic motor 19, FIG. 9 is a sectional view of the linear ultrasonic motor 19, and FIG. 10 is a linear ultrasonic motor as a modification of the third embodiment. FIG. 11... Mover, 12... tj41 piezoelectric element, 1
3a to 13d... second piezoelectric element, 14a, 14b.
... Vibrating body, 17a, 17b, 17e, 17d - Fixed rail, 20... Mover, 24... First excitation part,
28...excitation i of tJIJ2, 32...first rail, 33...@2 rail.

Claims (4)

[Claims] 1. a first member; a second member in contact with the first member; and an excitation means for exciting approximately elliptical vibration in a contact portion of the second member with the younger member 1; In a linear ultrasonic motor that relatively moves the first member and the second member using a driving force generated by approximately elliptical vibration excited by an excitation means, the second member moves in the moving direction. contact with the first member at least two locations located apart in a direction substantially orthogonal to the first member, and the drive speed generated by substantially elliptical vibration at the two contact portions can be independently changed. Linear ultrasonic motor. 2. the second member is excited by the excitation means,
It has a vibrating body that generates substantially circular vibration with at least one of a major axis or a minor axis having a different length with respect to each position in a predetermined direction, and the first member is in contact with the vibrating body so as to be slidable in the predetermined direction. The linear ultrasonic motor according to claim 1, characterized in that: 3. 2. The first member includes two rails of non-uniform thickness that are in contact with a surface of the second member on which approximately elliptical vibration is excited by the excitation means. Linear ultrasonic motor. 4. 2. The linear ultrasonic motor according to claim 1, wherein the excitation means has a first excitation section and a second excitation section, and excites the two contact sections independently.