JPH1146485A - Supersonic motor and its rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the management of the tightening torque of a supersonic motor and obtain its desired rotational characteristic, by generating a longitudinal vibration in its stator, and by providing in its rotor a vibration converting means for converting the longitudinal vibration into a torsional vibration. SOLUTION: A supersonic motor includes a stator 1 which has first and second blocks 3, 4, first and second piezoelectric elements 5, 6, and first and second electrode plates 7, 8, and a rotor 2 with a plurality of slits 12 formed as a vibration converting means. The first electrode plate 7 of the stator 1 is connected electrically with the second block 4 via the first block 3 and through a bolt 9. Therefore, using the second electrode plate 8 as a common electrode plate, high-frequency AC voltages are applied to the first and the second piezoelectric elements 5, 6 in the upside-down polarity of the element 6. As a result, when the first piezoelectric element 5 expands and contracts, the second piezoelectric element 6 also contracts and expands. Then, transferring a longitudinal vibration generated in the stator 1 to the rotor 2, a torsional vibration is so generated in the rotor 2 by the slits 12 formed in it that the longitudinal and torsional vibrations give respectively a buoyancy and torque to the rotor 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor and a rotor used for the same.

[0002]

2. Description of the Related Art As an ultrasonic motor, there is a standing wave type as shown in FIG. This ultrasonic motor has a rotor 8
0 and a stator 81. Stator 81
Is composed of blocks 82 to 84, piezoelectric elements 85 and 86, and electrode plates 87 and 88, each of which is a single bolt 89.
And are connected. Also, the rotor 8
0 is the bolt 8 protruding from the upper surface of the stator 81.
The rotor 9 and the stator 81 are tightened by a nut 90 and pressed against each other. A plurality of slits 83a are formed on the peripheral surface of the block 83.

In this ultrasonic motor, when a high frequency voltage is applied to the electrode plates 87, 88, the piezoelectric elements 85, 86 generate longitudinal vibration. The longitudinal vibration transmitted to the stator 81 causes the stator 81 to generate torsional vibration by the slit 83a formed in the block 83. Then, the longitudinal vibration and the torsional vibration are combined and the stator 81 which comes into contact with the rotor 80 is formed.
The rotor 80 is rotated by the elliptical vibration generated on the contact surface.

[0004]

By the way, the rotor 80
The rotation characteristics of the slit 83 a
The value a changes depending on the tightening state of the block 83 formed.

However, the slit 83a of the block 83 is different from the block 83 in that
When the bolt 6 is tightened with the bolt 6, buckling or distortion may occur on the basis of the tightening torque, and it is difficult to manage the tightening torque in order to obtain desired rotational characteristics.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic motor capable of easily controlling a tightening torque and obtaining desired rotational characteristics.

[0007]

According to a first aspect of the present invention, there is provided an ultrasonic motor in which a rotor is pressed against a stator to rotate the rotor based on the vibration generated in the stator. It is longitudinal vibration, and the gist is that the rotor has a vibration converting means for converting the longitudinal vibration into torsional vibration.

According to a second aspect of the present invention, in the ultrasonic motor according to the first aspect, the vibration converting means is a slit. According to a third aspect of the present invention, in the ultrasonic motor according to the second aspect, the slit is inclined.

According to a fourth aspect of the present invention, there is provided a rotor of an ultrasonic motor which rotates based on longitudinal vibration generated in a stator, wherein the rotor has vibration converting means for converting the longitudinal vibration into torsional vibration. .

According to a fifth aspect of the present invention, in the rotor of the ultrasonic motor according to the fourth aspect, the vibration converting means is a slit. . Claim 6
The gist of the present invention is that, in the rotor of the ultrasonic motor according to the fifth aspect, the slit is inclined.

According to the first aspect of the present invention, longitudinal vibration is generated in the stator, and torsional vibration is generated in the rotor pressed against the stator by the vibration converting means. The longitudinal vibration becomes the buoyancy of the rotor, and the torsional vibration becomes the rotational force of the rotor, so that the rotor rotates. Therefore, this ultrasonic motor does not require means for generating torsional vibration in the stator. As a result, the management of the tightening torque of the stator becomes easy.

According to the second aspect of the present invention, since the vibration converting means of the rotor is a slit, strong torsional vibration is generated, and desired rotational characteristics can be obtained efficiently.

According to the third aspect of the present invention, since the slit is inclined, a strong torsional vibration is generated, and a desired rotation characteristic can be obtained efficiently. According to the fourth aspect of the invention, when longitudinal vibration occurs in the stator, torsional vibration is generated by the vibration converting means. The longitudinal vibration becomes the buoyancy of the rotor, and the torsional vibration becomes the rotational force of the rotor, so that the rotor rotates. Therefore, this rotor does not require means for generating torsional vibration in the pressed stator. As a result, the management of the tightening torque of the stator becomes easy.

According to the fifth aspect of the present invention, since the vibration converting means is a slit, strong torsional vibration is generated, and the ultrasonic motor can efficiently obtain desired rotational characteristics.

According to the sixth aspect of the present invention, since the slit is inclined, strong torsional vibration is generated, and desired rotational characteristics can be obtained efficiently.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view of the entire ultrasonic motor. FIG. 2 is an exploded perspective view of the ultrasonic motor. FIG. 3 is a longitudinal sectional view of a main part of the ultrasonic motor. FIG. 4 shows the bottom surface of the rotor 2.

The ultrasonic motor has a stator 1 and a rotor 2. The stator 1 includes first and second blocks 3,
4, first and second piezoelectric elements 5 and 6, and first and second electrode plates 7 and 8.

The first block 3 is made of a conductive metal, and in this embodiment, is made of an aluminum alloy. The first block 3 is a cylindrical body, and a screw hole 3a penetrating in the axial direction is formed in a central shaft portion thereof. Second block 4
Is made of a conductive metal, and is formed of an aluminum alloy in this embodiment. The second block 4 is a cylindrical body, and a screw hole 4a penetrating in the axial direction is formed in a central shaft portion thereof. On the lower surface 4c of the second block 4, a storage recess 4 is provided.
d is formed.

Between the lower surface 3c of the first block 3 and the upper surface 4b of the second block 4, first and second piezoelectric elements 5, 6 and first and second electrode plates 7, 8 are provided. Have been. Specifically, from the lower surface 3c of the first block 3 to the upper surface 4b of the second block 4, a first electrode plate 7, a first piezoelectric element 5, a second electrode plate 8, and a second piezoelectric element 6 are laminated in this order. You.

The first and second piezoelectric elements 5 and 6 are formed in a disk shape, and through holes 5a and 6a are formed in the center thereof. The first and second piezoelectric elements 5 and 6 are formed such that the polarization directions are upside down.

The first and second electrode plates 7 and 8 are formed in a disk shape, and through holes 7a and 8a are formed in the center thereof. Terminal pieces 7b and 8b are formed on the peripheral surfaces of the first and second electrode plates 7 and 8, respectively.
A high frequency AC voltage is applied between 8b.

Then, the first and second blocks 3 and 4 are fastened with bolts 9. Specifically, as shown in FIG.
The first and second blocks 3 and 4 hold the first and second piezoelectric elements 5 and 6 stacked in the above order and the first and second electrode plates 7 and 8 and hold the bolt 9 in the second position. It is fastened by being screwed into the screw hole 3a of the first block 3 from the screw hole 4a in the accommodation recess 4d of the block 4.

As shown in FIG. 3, the first and second piezoelectric elements 5, 6 and the first and second piezoelectric elements 5 and 6 are laminated in a predetermined order.
A cylindrical insulating collar 10 is provided in the through holes 5 a to 8 a of the electrode plates 7 and 8, and the bolt 9 passes through the inside of the collar 10. Then, the first and second piezoelectric elements 5 and 6 and the first and second electrode plates 7 and 8 are
Are electrically insulated from each other.

The bolt 9 has a screw portion 9a screwed to the first and second blocks 3 and 4 as described above, and a pole portion having a small diameter from the tip of the screw portion 9a and extending in the axial direction. 9b and a tip screw portion 9 formed at the tip of the pole portion 9b.
c is formed. In a state where the first and second blocks 3 and 4 are fastened with bolts 9, the top end of the first block 3 extends from the substantially middle position of the pole portion 9 b.
b.

On the upper surface 3b of the first block 3, a rotor 2 is provided. The rotor 2 is a cylindrical body made of stainless steel, and has a through hole 2a penetrating in the axial direction at the center axis thereof. A first housing recess 2d is formed in the upper surface 2b of the rotor 2, and
A second housing recess 2e is formed on the bottom surface of the housing recess 2d. A lining material 11 is provided on the lower surface 2 c of the rotor 2, and the lining material 11 contacts the upper surface 3 b of the first block 3. Then, the upper surface 3 of the first block 3
The surface of the lining material 11 that comes into contact with b is a contact surface 11a.

A plurality of slits 12 are formed on the outer peripheral surface of the lower part of the rotor 2 as vibration converting means. More specifically, as shown in FIG. 4, the plurality of slits 12 are formed at equal angular intervals, and the lower surface 2c (the lining material 1) of the rotor 2 is formed.
The cut of each slit 12 as viewed from the first contact surface 11a) extends from the outer peripheral surface toward the center to a substantially intermediate position. Each slit 12 is cut from the cut surface of each slit 12 viewed from the lower surface 2 c of the rotor 2 so as to be inclined at the same inclination angle with respect to the center axis of the rotor 2. In the present embodiment, as viewed from the outer peripheral surface of the rotor 2, each slit 12 is formed to extend diagonally upward in a counterclockwise direction to a substantially intermediate position of the rotor 2.

The stator 1 and the rotor 2 are connected to the bolt 9
And the nut 13 are tightened.
Are slidably slidably pressed against. More specifically, the ball bearing 14 is fitted into the second housing recess 2 e of the rotor 2, and the inner peripheral surface 14
a, the pole portion 9b protruding from the upper surface 3b of the first block 3 is made to penetrate, and the tip screw portion 9c is protruded into the first housing recess 2d of the rotor 2. Then, the spring receiver 15 and the disc spring 1
In a state in which the nut 6 is inserted, the nut 13 is screwed into the screw portion 9c at the tip and tightened. By this tightening, the leaf spring 1
The inner race 14b of the ball bearing 14 is pressed downward via the spring 6 and the spring receiver 15. Then, the rotor 2 is moved through the outer race 14c of the ball bearing 14.
Is pressed against the stator 1. At this time, the rotor 2 is slidably rotated by the ball bearing 14.

When the desired high-frequency AC voltage is applied to the first and second electrode plates 7 and 8 from a voltage applying device (not shown), the stator 1 of the ultrasonic motor having the above-described configuration is used. The piezoelectric elements 5 and 6 generate longitudinal vibration.

More specifically, since the first electrode plate 7 is electrically connected to the second block 4 via the first block 3 and the bolt 9, the second electrode plate 8 is shared and the first electrode plate 7 is connected to the second block 4. 1
A high-frequency AC voltage is applied to the second piezoelectric elements 5 and 6 with an inverted polarity. Since the polarization directions of the first and second piezoelectric elements 5 and 6 are upside down, when the first piezoelectric element 5 expands, the second piezoelectric element 6 also expands and when the first piezoelectric element 5 contracts. , The second piezoelectric element 6 also contracts. Therefore, the first and second piezoelectric elements 5 and 6 generate longitudinal vibration having a large amplitude.

The longitudinal vibration generated in the stator 1 is transmitted to the rotor 2. Then, torsional vibration occurs in the slits 12 formed in the rotor 2, and the longitudinal vibration gives buoyancy to the rotor 2, and the torsional vibration gives a rotational force to the rotor 2.
Therefore, the rotor 2 rotates.

Next, the characteristic operation and effect of the ultrasonic motor configured as described above will be described below. (1) In this embodiment, since the slits 12 are formed in the rotor 2, when the stator 1 generates longitudinal vibration, the rotor 2
The rotor 2 generates a torsional vibration due to the slit 12. Therefore, the rotor 2 rotates. As a result, there is no need for a means for generating torsional vibration such as a slit in the stator 1 and the management of the tightening torque when tightening the blocks 3 and 4 becomes easy.

(2) In the present embodiment, since the rotor 2 generates torsional vibration and rotates itself, the rotor 2 can be easily rotated simply by removing the nut 13 and replacing the rotor 2 having a different shape of the slit 12. Ultrasonic motors having different characteristics can be provided. Therefore, the stators of the ultrasonic motors having different rotation characteristics can be the same, and the stator having a complicated configuration can be standardized. as a result,
The cost of the ultrasonic motor can be reduced.

(3) In the present embodiment, the stator 1 only needs to be able to generate only longitudinal vibration, so that the size of the stator can be reduced. (4) In the present embodiment, the first and second blocks 3 and 4 of the stator 1 are made of an aluminum alloy. Therefore, the weight of the ultrasonic motor is reduced.

The embodiment of the present invention is not limited to the above embodiment, but may be carried out as follows. In the above embodiment, the members 3 to 8 constituting the stator 1 are fastened and connected by the bolts 9, and the stator 1 and the rotor 2 are pressed against each other by the bolts 9 and the nuts 13. For example, as shown in FIG. 5, the stator 1 has no shaft portion 17a and has a head at one end of the shaft portion 17a. The rivet 17 in which the portion 17b is formed is penetrated through the through holes 3a to 8a of the members constituting the stator 1 and is strongly connected by means of an oak stopper or the like, and the rotor is pressed against a predetermined surface by pressing from the outside. It may be configured. Even in this case, the same effects as the effects (1) to (4) of the above embodiment can be obtained.

The rotor 2 of the above embodiment may be any rotor as long as it has a vibration converting means. For example, the rotor 2 may be changed to the rotor 21 shown in FIGS. FIG. 6A shows the rotor 2.
1 shows a top view, and FIG. 6B shows a side view of the rotor 21. The rotor 21 is provided with a lining material 22 on a lower surface, that is, a contact surface with the stator 1, and a plurality of slits 23 extend obliquely clockwise downward from the upper surface as viewed from the outer peripheral surface to a substantially intermediate position of the rotor 21. It is formed. Even in this case, the effect (1) of the above embodiment can be obtained.
The same effects as in (4) can be obtained.

The rotor 2 may be changed to a rotor 31 shown in FIGS. 7 (a) and 7 (b). FIG. 7A shows the rotor 3.
1 is a top view, and FIG. 7B is a side view of the rotor 31. The rotor 31 is provided with a lining material 32 on a lower surface, that is, a contact surface with the stator 1, and formed with a plurality of slits 33 extending obliquely counterclockwise from the lower surface to the upper surface as viewed from the outer peripheral surface. I have. Even in this case, the same effects as the effects (1) to (4) of the above embodiment can be obtained. In addition, the slits 33 having the cuts penetrating the upper and lower surfaces can be easily formed by cutting.

The rotor 2 may be changed to a rotor 35 shown in FIG. In the rotor 35, a plurality of contact pieces 37 as vibration converting means are arranged on the lower surface of a cylindrical main body 36 at equal angular intervals. This contact piece 37 is
Is formed to extend clockwise and obliquely downward as viewed from the lower surface of the. A lining material 38 is provided on the lower surface of the contact piece 37, that is, on the contact surface with the stator 1.
Even in such a case, the effects (1) to (5) of the above embodiment can be obtained.
The same effect as (4) can be obtained.

The stator 1 of the above embodiment may be any stator as long as it can generate longitudinal vibration. For example, the stator 1 may be changed to a stator 41 shown in FIG. This stator 41
The block 42 on the contact surface side with the rotor 2 is formed with a concave portion 43 that is hollowed out in a cylindrical shape. By doing so, the longitudinal vibration generated in the stator 41 is efficiently transmitted to the rotor 2.

The stator 1 may be changed to a stator 51 shown in FIG. In the stator 51, an upper end block 52 and a lower end block 53 are formed vertically shorter. By doing so, the shape of the ultrasonic motor is shortened and the size is reduced.

The stator 1 may be changed to a stator 61 shown in FIG. The diameter of the stator 61 decreases as the block 62 on the contact surface side with the rotor 2 approaches the contact surface side. With this configuration, the longitudinal vibration generated in the stator 61 is efficiently transmitted to the rotor 2.

The stator 1 may be changed to a stator 71 shown in FIG. The stator 71 has an upper end block 72 that is long and a lower end block 73 that is short.

[0042]

According to the first aspect of the present invention, it is possible to provide an ultrasonic motor capable of easily controlling the tightening torque of the stator.

According to the second and third aspects of the invention, in addition to the effects of the first aspect of the invention, it is possible to provide an ultrasonic motor capable of efficiently obtaining desired rotational characteristics.

According to the fourth aspect of the present invention, it is possible to provide an ultrasonic motor rotor in which the tightening torque of the stator can be easily controlled. According to the fifth and sixth aspects of the invention, in addition to the effect of the fourth aspect of the invention, it is possible to provide a rotor of an ultrasonic motor capable of efficiently obtaining desired rotational characteristics.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an ultrasonic motor according to an embodiment.

FIG. 2 is an exploded perspective view of the ultrasonic motor according to the embodiment.

FIG. 3 is a longitudinal sectional view of a main part of the ultrasonic motor according to the embodiment.

FIG. 4 is an explanatory diagram for explaining a bottom surface of a rotor according to the embodiment.

FIG. 5 is a longitudinal sectional view of an essential part of an ultrasonic motor in another example.

FIG. 6A is a top view of a rotor in another example. (B) The side view of the rotor in another example.

FIG. 7A is a top view of a rotor in another example. (B) The side view of the rotor in another example.

FIG. 8 is a perspective view of a rotor in another example.

9A to 9D are side views of another example of a stator.

FIG. 10 is an overall perspective view of an ultrasonic motor according to the related art.

[Explanation of symbols]

1, 41, 51, 61, 71 ... stator, 2, 21, 3
1, 35 ... rotor, 12, 23, 33 ... slit, 37
... contact pieces.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazumasa Kubota 20 Oyamazuka, Oiwa-cho, Toyohashi-shi, Aichi Honda Honda Electronics Co., Ltd.

Claims (6)

[Claims] A stator (1, 41, 51, 61, 7)
The rotor (2, 21, 31, 35) is pressed against 1),
An ultrasonic motor for rotating the rotor (2, 21, 31, 35) based on vibration generated in the stator (1, 41, 51, 61, 71), wherein the stator (1, 41, 51, 61, 71) ) Is a longitudinal vibration, and the rotor (2, 21, 31, 3)
5) An ultrasonic motor having vibration converting means (12, 23, 33, 37) for converting the longitudinal vibration into torsional vibration. 2. The ultrasonic motor according to claim 1, wherein said vibration converting means is a slit. 3. The ultrasonic motor according to claim 2, wherein said slits (12, 23, 33) are inclined. 4. A stator (1, 41, 51, 61, 7).
In a rotor of an ultrasonic motor that rotates based on longitudinal vibration generated in 1), a vibration conversion unit (1) that converts the longitudinal vibration into torsional vibration.
(2, 23, 33, 37). 5. The ultrasonic motor rotor according to claim 4, wherein said vibration converting means is (12, 23, 33, 37) and a slit (12, 23, 33). Motor rotor. 6. The rotor for an ultrasonic motor according to claim 5, wherein said slits (12, 23, 33) are inclined.