JP2002044968A - Ultrasonic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic motor which can self-cool, without having to provide a fan separately. SOLUTION: The standing wave type ultrasonic motor 1 has a stator 2 and rotor 3. A plurality of slits 14 are formed on the outer peripheral surface of the cylindrical shape rotor 3. The slits 14 are formed at respective spacings at equal angles and sloping clockwise downwardly from the upper face 3b of the rotor 3. Each fin 15 is fixed in each slit 14. The upper edge of each fin 15 is made as one with the peripheral edge of a disk-shaped supporting plate 16, made of resin and the supporting plate 16, is fixed on the upper face 3b of the rotor 3. Each fin 15, made of resin having approximately a rectangular shape, is inserted from the top edge to the bottom edge of each slit 14 and protrudes in the radial direction. The thickness of each fin 15 is formed approximately the same as the width of the slit 14 in the circumferential direction, and each fin 15 is fixedly coupled in each slit 14.

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 more particularly, to an ultrasonic motor having a feature in a cooling fin mounting structure.

[0002]

2. Description of the Related Art Conventionally, motors such as a DC motor and an ultrasonic motor generate heat when continuously operated, and the performance of the motor deteriorates. In order to suppress this heat generation, a separate fan is provided for cooling. As an ultrasonic motor, for example, Japanese Unexamined Patent Publication No.
The one disclosed in 199986 is known. The ultrasonic motor disclosed in this publication is of a standing wave type, in which longitudinal vibration generated in a piezoelectric element in a stator by voltage application is transmitted to a rotor, and torsional vibration is caused by the presence of a plurality of slits formed in the rotor. Converted, the rotor rotates.

[0003]

However, there is a problem that providing a separate fan increases the cost. The present invention has been made to solve the above problems, and an object of the present invention is to provide an ultrasonic motor that can perform self-cooling without providing a separate fan.

[0004]

In order to solve the above-mentioned problems, the invention according to the first aspect is directed to a stator in which a piezoelectric element is sandwiched between block bodies and a vibration is generated by voltage application;
In an ultrasonic motor including a rotor which is pressed against the stator and rotated by the vibration of the stator and has a slit formed on a peripheral surface, a fin is fixed to the slit. According to the present invention, the fin fixed to the slit rotates with the rotation of the rotor to generate wind, and the motor is cooled. Therefore, self-cooling of the motor can be performed without providing a separate fan.

According to a second aspect of the present invention, in the first aspect, the fin projects at least in a radial direction of the rotor. According to this invention, the fins projecting in the radial direction rotate with the rotation of the rotor to generate wind. Therefore, wind is more likely to be generated than when the fins protrude in the axial direction.

According to a third aspect of the present invention, in the first aspect, the fins protrude in the axial direction of the rotor and do not protrude in the radial direction.
Therefore, according to the present invention, the fin can be fixed to the slit without increasing the radial volume of the motor.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the fin is integrally formed at one end with a support plate, and the support plate is provided with the rotor. The point is that it is provided so as to contact the surface on the opposite side of the stator. According to the present invention, when the fins are fixed to the slits, the fins are arranged so as to face the slits, and then the support plate is pushed toward the rotor, and the fins are inserted into the slits. Therefore, the fins are easy to handle, and can be attached to the slit at once.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of an ultrasonic motor, and FIG. 2 is an exploded perspective view of a stator, a rotor, and fins.

As shown in FIGS. 1 and 2, a standing wave type ultrasonic motor 1 includes a stator 2 and a rotor 3. Note that the rotor 3 side is the upper side of the ultrasonic motor 1.
The stator 2 includes a first block 4, a first electrode plate 5, a first piezoelectric element 6, a second electrode plate 7, a second piezoelectric element 8, and a second block 9 in order from the bottom.

Screw holes 4a, 9a penetrating in the axial direction are respectively formed at the center portions of the first and second cylindrical blocks 4, 9 respectively.
Are formed. A plurality of slits 11 (shown only in FIG. 2) are formed on the outer peripheral surface of the first block 4.
The slits 11 are arranged at equal angular intervals on the upper surface 4 of the first block 4.
It is formed to be inclined counterclockwise downward from b. The upper surface 9b of the second block 9 is formed with a concave portion 9c which is hollowed out in a cylindrical shape, and the lining material 10 is formed on the annular upper surface 9b.
Is provided, and the upper surface 10a of the lining material 10 is
Abut on the lower surface 3c.

As shown in FIG. 1, first and second disc-shaped first and second discs are provided.
Through holes 5a to 8a are formed in the center portions of the electrode plates 5, 7 and the first and second piezoelectric elements 6, 8, respectively. First
And terminal pieces 5 on the peripheral surfaces of the second electrode plates 5 and 7, respectively.
b, 7b are formed.

The first and second blocks 4 and 9 are screwed to connecting bolts 12. Substantially cylindrical coupling bolt 12
The threaded portion 12b is formed from each end to the central portion 12a except for the central portion 12a. One screw part 12b
Is screwed into the screw hole 4a of the first block 4, and the other screw portion 12b is screwed and fixed to the screw hole 9a of the second block 9. Both screw portions 12b are formed in opposite directions. A cylindrical insulating collar 13 is provided in the through holes 5a to 8a, and a central portion 12a of the coupling bolt 12 is inserted inside the insulating collar 13.

At the center of the columnar rotor 3, a through hole 3a is formed.
Are formed. A plurality of slits 14 are formed on the outer peripheral surface of the rotor 3. The slits 14 are formed at equal angular intervals and inclined clockwise downward from the upper surface 3b of the rotor 3.

Each slit 14 has a fin 15
Has been fixed. As shown in FIGS. 1 and 2, the upper end of each fin 15 is formed integrally with the periphery of a disc-shaped support plate 16 made of resin, and the support plate 16 is in contact with the upper surface 3 b of the rotor 3. . In FIG. 1, the rotor 3 and the stator 2
In some cases, the illustration of the fins 15 is omitted in order to make the drawing as simple as possible.

A generally rectangular fin 15 made of resin is inserted from the upper end to the lower end of the slit 14 and protrudes radially. The thickness of the fins 15 is substantially the same as the width of the slit 14 in the circumferential direction, and each fin 15 is fitted and fixed to the slit 14. The fins 15 are inserted into and fixed to the slits 14 from the outer peripheral surface of the rotor 3 toward the center to a substantially intermediate position of the fins 15. Outside the lower end of the fin 15 projecting in the radial direction,
a is formed.

A shaft 17 is provided in the through hole 3a of the rotor 3.
Has been fixed. A spring receiver 18 is fixed to the shaft 17, and a disc spring 19 is arranged between the spring receiver 18 and the support plate 16. The support plate 16 and the rotor 3 are pressed downward by the urging force due to the elasticity of the disc spring 19, and the lower surface 3 c of the rotor 3 is slidably pressed against the upper surface 10 a of the lining material 10. A key groove (not shown) is formed in the rotor 3 and the shaft 17, and the rotor 3 and the shaft 17 can be integrally rotated via a key fitted in the key groove.

The stator 2 and the rotor 3 are housed in a housing. The metal housing includes a lower housing 20 and an upper housing 21. The stator 2 includes a resin-made insulating flange 2 attached to a peripheral surface of the first block 4 in a fitting recess 22 formed inside an opening end of a lower housing 20 having a bottomed cylindrical shape.
3 are fitted and fixed. A flange 20a is formed outside the opening-side end of the lower housing 20. The shaft 17 is rotatably supported by the upper housing 21 via a bearing 24.

Next, the assembly of the fin 15 to the slit 14 will be described. After arranging each fin 15 so as to face the slit 14, the support plate 16 is pushed toward the rotor 3, and the fin 15 is inserted into each slit 14 and fitted and fixed. Therefore, the fins 15 are collectively
4 and can be fixed.

Next, the operation of the ultrasonic motor 1 configured as described above will be described. When a predetermined high-frequency AC voltage is applied between the terminal pieces 5b and 7b from a voltage application device (not shown), longitudinal vibrations are generated in the first and second piezoelectric elements 6 and 8.
This longitudinal vibration is transmitted to the first block 4 and the rotor 3,
Due to the presence of the slits 11 and 14, torsional vibration occurs. Since the longitudinal vibration gives buoyancy to the rotor 3 and the torsional vibration gives a rotational force to the rotor 3, the rotor 3 rotates. The fins 15 rotate with the rotation of the rotor 3 to generate wind.
This wind cools the ultrasonic motor 1.

As described above, according to this embodiment, the following effects can be obtained. (1) Since the fins 15 are fixed to the slits 14 of the rotor 3, the fins 15 rotate with the rotation of the rotor 3, generating wind and cooling the ultrasonic motor 1. Therefore, continuous operation is possible in order to suppress heat generation and prevent performance deterioration of the ultrasonic motor 1 without providing a separate fan.

(2) Since the fins 15 protrude in the radial direction of the rotor 3, wind is more likely to be generated than when the fins protrude in the axial direction. (3) Since the fins 15 are formed so as to prevent the rotor 3 from projecting in the axial direction, an increase in the volume of the ultrasonic motor 1 in the axial direction can be reduced.

(4) Since each fin 15 is formed integrally with the support plate 16, it is easy to handle and can be attached to the slit at one time. (5) Since the fins 15 are made of resin, they are lighter than, for example, those made of metal and consume less power for rotating the rotor 3. Furthermore, since the elasticity is higher than that of metal or the like, even if the thickness of the fins 15 is formed to be substantially the same as the circumferential width of the slits 14 and the fins 15 are fitted and fixed to the slits 14, the torsion due to the presence of the slits 14 can be obtained. Does not prevent the generation of vibration.

(6) Since the housings 20 and 21 are made of metal, the required strength can be ensured even if they are thin. (7) The upper surface 10a of the lining material 10 is formed in an annular shape due to the concave portion 9c formed in the upper surface 9b of the second block 9, and is in contact with the lower surface 3c of the rotor 3. With such a configuration, the longitudinal vibration and the torsional vibration generated in the stator 2 are efficiently transmitted to the rotor 3.

(8) First block 4 and lower housing 2
0 means that the insulation is maintained because of the flange 23 disposed between the two. Therefore, it is not necessary to separately provide an insulating material.

The embodiment is not limited to the above-described embodiment, and may be modified as follows, for example. -Instead of integrally forming the fin 15 and the support plate 16,
As shown in FIG. 3A, independent fins 31 may be provided. When the fins 31 are assembled, the rotor 3
Project in the radial direction and do not project in the axial direction. FIG.
As shown in (b), the fins 32 that project in the axial direction of the rotor 3 when assembled and do not project in the radial direction may be used. In this case, the fins 32 can be provided without increasing the radial volume of the ultrasonic motor.

The fins 15 may project in both directions of the radial axis of the rotor 3. In this case, wind is generated efficiently. The fins 15 are not limited to resin and may be, for example, rubber or metal. In the case of rubber, since the elasticity is higher than that of metal, for example, the thickness of the fin 15 is formed to be substantially the same as the width of the slit 14 in the circumferential direction. It does not prevent the occurrence of torsional vibration due to the presence of 14. When the fin 15 is made of metal, the thickness of the fin 15 is made smaller than the width of the slit 14 in the circumferential direction so as not to hinder the occurrence of torsional vibration.
And fix it leaving a gap in the circumferential direction.

The fins 15 may be fixed without leaving a gap in the radial direction of the slit 14. Even in this case, for example, the resin or rubber fin 15 has higher elasticity than metal or the like,
The generation of torsional vibration due to the presence of the slit 14 is not prevented.

The housings 20, 21 are not limited to metal and may be, for example, resin. A ventilation hole may be formed in each of the housings 20 and 21. In this case, the wind easily passes.

The ultrasonic motor 1 has two housings 20,
21 may not be provided. In this case, for example, Japanese Patent Application Laid-Open
As disclosed in JP-A-199986, the stator 2 and the rotor 3 are slidably pressed against each other by bolts and nuts.

The slit 11 of the first block 4 need not be formed. Even in this case, torsional vibration occurs due to the presence of the slits 14 formed in the rotor 3, and the rotor 3 rotates.

The number of the slits 14 and the number of the fins 15 of the rotor 3 need only be plural. -The number of the fins 15 may be less than the number of the slits 14.

The fixing between the first block 4 and the lower housing 20 is not limited to forming the fitting recess 22 in the lower housing 20 and fitting the flange 23 provided on the first block 4. For example, the fitting recess 22 is not formed in the lower housing 20, and the first block 4 is provided with a thin flange in contact with the upper surface of the flange 20 a of the lower housing 20 instead of the flange 23, and the two are fastened with bolts Let it.

The ultrasonic motor may be formed as, for example, a blower or an electric fan. In this case, for example, the shape of the housing is changed, a ventilation hole is formed in the housing, and air is blown out of the ultrasonic motor. Further, the fins may be increased in order to increase the amount of generated air.

Next, technical ideas other than those described in the claims that can be understood from the above embodiments will be described below. (1) In the invention according to any one of claims 1 to 4, the ultrasonic motor is formed as, for example, a blower or an electric fan.

(2) In the invention described in any one of claims 1 to 4 or the technical idea (1), the fin is provided in all the slits of the rotor.

[0036]

As described in detail above, according to the first to fourth aspects of the present invention, self-cooling can be performed without providing a separate fan.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an ultrasonic motor.

FIG. 2 is an exploded perspective view of a stator, a rotor, and fins.

3A is an exploded perspective view of another example of a rotor and fins, and FIG. 3B is an exploded perspective view of another example different from FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic motor, 2 ... Stator, 3 ... Rotor, 4 ... 1st block as a block body, 6 ... 1st piezoelectric element, 8
... A second piezoelectric element, 9... A second block as a block body, 14. A slit, 15. A fin, 16.

Claims (4)

[Claims] 1. A super-compact comprising: a stator in which a piezoelectric element is sandwiched between block bodies to generate vibrations by applying a voltage; and a rotor which is pressed against the stator and rotated by the vibrations of the stator to form a slit in a peripheral surface. An ultrasonic motor, wherein a fin is fixed to the slit. 2. The ultrasonic motor according to claim 1, wherein the fin projects at least in a radial direction of the rotor. 3. The ultrasonic motor according to claim 1, wherein the fin projects in an axial direction of the rotor and does not project in a radial direction. 4. The fin is formed integrally with a support plate at one end, and the support plate is provided so as to abut on a surface of the rotor opposite to the stator.
The ultrasonic motor according to claim 3.