JPH0866062A - Ultrasonic motor - Google Patents

Abstract

PURPOSE: To obtain an ultrasonic motor which prevents a piezoelectric element from being exfoliated from an elastic body, in which the time to attach and fix the piezoelectric element to the elastic body is shortened and in which the piezoelectric element can be attached easily to the elastic body. CONSTITUTION: In an ultrasonic motor, a rotor 15 is brought into contact with a protrusion 21 installed by forming a slit in a stator 10, an AC voltage is applied to piezoelectric elements 23a, 23b which are attached to an elastic body 10a, the protrusion 21 is vibrated, and the rotor 15 which comes into contact with the protrusion 21 is turned by its vibration. The piezoelectric elements 23a, 23b are molded by a resin 25 so as to be fixed to the elastic body 10a.

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 which prevents peeling of a piezoelectric element attached to an elastic body forming a stator.

[0002]

2. Description of the Related Art A conventional ultrasonic motor is shown in FIG. When alternating voltages having different 90 ° phase shifts are applied to the piezoelectric elements 72a and 72b provided on the lower surface of the metallic elastic body 71a that constitutes the stator 71, the stator 71 vibrates. In addition, the slit 73 is formed on the upper surface of the stator 71.
The formation of the projections 74 forms the projections 74, and the projections 74 vibrate in the vertical and horizontal directions. The rotor 75 and the output shaft 76 that are in contact with the protrusion 74 rotate due to the vibration of the protrusion 74. A lining material 75a made of Teflon resin is provided on the lower surface of the rotor 75 so that the rotor 75 can smoothly rotate.

[0003]

By the way, the piezoelectric element 7 is used.
2a and 72b are attached and fixed to the elastic body 71a with an adhesive. Therefore, when the AC voltage is applied to the piezoelectric elements 72a and 72b to rotate the rotor 75, the piezoelectric elements 72a and 72b expand and contract. This piezoelectric element 72
The piezoelectric elements 72a and 72b may be separated from the stator 71 due to the expansion and contraction of a and 72b.

Further, the piezoelectric elements 72a and 72a are attached to the elastic body 71a.
When attaching and fixing b, the elastic body 71a or the piezoelectric element 72
After applying the adhesives to a and 72b so that they are even, they are stuck together and left in a high temperature atmosphere for several hours. Therefore, there is a problem that the bonding work for attaching and fixing the piezoelectric elements 72a and 72b to the elastic body 71a is troublesome.

Further, the base 78 and the cover 79 which form the case 77 of the ultrasonic motor are often made of metal. Therefore, the base 78 and the piezoelectric elements 72a and 72b
Insulating agent is applied to the lower surfaces of the piezoelectric elements 72a and 72b in order to ensure the insulation between them. Therefore, there is a problem that the insulation process must be performed, and the work is very troublesome.

In order to smoothly rotate the rotor 75, the rotor 75 is provided with a lining material 75a. Further, the protrusions 74 are formed on the stator 71 by the slits 7.
3 is provided. There is a problem that the work of forming the slits 73 in the stator 71 and providing the protrusions 74 is very troublesome.

The present invention has been made to solve the above problems, and a first object thereof is to provide an ultrasonic motor which prevents the piezoelectric element from being separated from the elastic body.

A second object is to provide an ultrasonic motor which facilitates the formation of the protrusions formed on the stator. A third object is to provide an ultrasonic motor capable of further preventing the piezoelectric element from peeling off from the elastic body.

A fourth object is to provide an ultrasonic motor capable of rotating the rotor smoothly.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 vibrates the stator by applying an AC voltage to the piezoelectric element attached to the elastic body, and the vibration causes the stator to vibrate. The gist of the ultrasonic motor for rotating a rotor that is in contact with the stator is that the piezoelectric element is molded with resin and fixed to an elastic body.

The gist of the invention according to claim 2 is that a protrusion for contacting the rotor is formed by a resin for fixing the piezoelectric element to the elastic body. According to a third aspect of the present invention, the protrusion provided by forming a slit in the elastic body is brought into contact with the rotor, and an alternating voltage is applied to the piezoelectric element attached to the elastic body to vibrate the protrusion. In an ultrasonic motor that rotates a rotor that comes into contact with the protrusion due to this vibration, the piezoelectric element is molded with resin to be fixed to an elastic body, and the resin is poured into a slit of the elastic body. .

According to a fourth aspect of the present invention, the protrusion provided by forming a slit in the elastic body is brought into contact with the rotor, and an alternating voltage is applied to the piezoelectric element attached to the elastic body to project the protrusion. In an ultrasonic motor that vibrates the rotor and rotates the rotor that comes into contact with the protrusion due to this vibration, the piezoelectric element is molded with resin and fixed to an elastic body, and the upper surface of the protrusion formed on the elastic body is made into resin. It is the gist to cover it.

A fifth aspect of the present invention is characterized in that a lining material that comes into contact with the rotor is provided on the upper surface of the protrusion formed of resin or an elastic body. The gist of the invention according to claim 6 is that the piezoelectric element provided on the elastic body is completely covered with resin.

[0014]

According to the first aspect of the present invention, the piezoelectric element is molded with resin and is attached and fixed to the elastic body. Therefore, it is possible to prevent the piezoelectric element from being separated from the elastic body even when the piezoelectric element expands and contracts due to the application of the AC voltage.

According to the second aspect of the present invention, since the protrusion that comes into contact with the rotor is formed by the resin that molds the piezoelectric element and is attached and fixed to the elastic body, it is not necessary to form the protrusion on the elastic body. Therefore, it becomes possible to easily form the protrusion with the resin. Further, since the protrusion is made of resin, the rotor can be smoothly rotated by the resin protrusion. Further, it becomes possible to prevent the resin from peeling off from the elastic body and prevent the piezoelectric element from peeling off from the elastic body.

According to the third aspect of the invention, the piezoelectric element is molded with resin and is fixedly attached to the elastic body. The resin in which the piezoelectric element is molded is poured into the slit formed in the elastic body. Therefore, the resin molds the piezoelectric element and is securely attached to the elastic body. Therefore, it becomes possible to prevent the piezoelectric element from being further peeled from the elastic body even when the piezoelectric element expands and contracts due to the application of the AC voltage.

According to the fourth aspect of the invention, the upper surfaces of the piezoelectric element and the protrusion are molded with resin, and the piezoelectric element is attached and fixed to the elastic body. Therefore, it is possible to prevent the piezoelectric element from being separated from the elastic body even when the piezoelectric element expands and contracts due to the application of the AC voltage. Further, since the upper surface of the protrusion is covered with resin, the rotor can be smoothly rotated. Furthermore, since the resin covers the upper surfaces of the piezoelectric element and the protrusion, it is possible to prevent the piezoelectric element from being further peeled from the elastic body.

According to the fifth aspect of the present invention, it is possible to select an appropriate lining material according to a change in use environment, such as when a special lining characteristic is required in a special environment, and the rotor is It is possible to always rotate smoothly.

According to the sixth aspect of the invention, since the piezoelectric element is completely covered with the resin, the piezoelectric element does not need to be insulated.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in an ultrasonic motor will be described below with reference to FIGS.

As shown in FIG. 1, a main body case 1 which constitutes an ultrasonic motor comprises a base 2 and an upper cover 3, and a storage space 4 is formed from the base 2 and the upper cover 3. There is. A mounting portion 5 is formed so as to project from the central upper surface of the base 2, and a storage recess 6 is provided in the central lower surface of the base 2. An insertion hole 7 is formed in the center of the base 2, and the tip of the rotary shaft 8 is inserted into the storage space 4 through the insertion hole 7. The rotary shaft 8 is rotatably supported by a bearing 9 arranged in the storage recess 6.

A locking piece 5a is integrally formed on the outer peripheral edge of the insertion hole 7 on the upper surface of the mounting portion 5. Also, the mounting portion 5
Is made of metal (for example, sintered metal such as copper, aluminum)
An elastic body 10a, which is a component of the stator 10, is placed, the locking piece 5a is inserted upward into a through hole 11 formed in the elastic body 10a, and the upper end of the locking piece 5a is a through hole. It is engaged with the outer peripheral edge of 11. Therefore, the elastic body 10 a is locked and fixed to the mounting portion 5 of the base 2. The rotary shaft 8 is inserted through the through hole 11 of the elastic body 10a.

The elastic body 10a is provided with a supporting portion 12 placed on the placing portion 5, a thin portion 13 which is formed so as to project from the outer peripheral surface of the center of the supporting portion 12, and which is thinner than the supporting portion 12. The vibrating portion 14 is formed on the outer peripheral edge of the thin portion 13 and is thicker than the thin portion 13.

As shown in FIGS. 2 and 3, on the upper surface of the vibrating portion 14, radial slits 20 are formed around the through hole 11 with a predetermined interval. This slit 20
Thus, a plurality of protrusions 21 are provided on the upper surface of the vibrating portion 14 at a predetermined interval.

As shown in FIG. 1, a metallic rotor 15 made of aluminum or the like is mounted on the upper surface of the protrusion 21 of the vibrating portion 14. The rotor 1
Projections 16a and 16b projecting vertically are integrally formed on the outer circumference of the projection 5, and the projection 16b is placed on the projection 21. An insertion hole 16 is provided at the center of the rotor 15. The rotary shaft 8 is inserted into the insertion hole 16, and the tip end of the rotary shaft 8 is the rotor 1
It is in a state of protruding to the upper part of 5. Further, the rotor 15 and the rotary shaft 8 are in a fixed state, and the rotor 1
When 5 is rotated, the rotary shaft 8 is integrally rotated. The rotor 15 is grounded via the rotary shaft 8.

The elastic member 1 is provided on the upper surface of the rotor 15.
7 is placed, and the elastic member 17 presses the rotor 15 downward by a nut 18 or the like that is screwed into a male screw 8a provided at the tip of the rotary shaft 8. Therefore, the rotor 15 is placed in pressure contact with the upper surface of the protrusion 21 of the stator 10.

On the lower surface of the vibrating portion 14 of the elastic body 10a, a pair of piezoelectric elements 23a and 23b formed in a semicircular shape, which are elements constituting the stator 10, are arranged in an annular shape. In addition, the piezoelectric elements 23a and 23b
The printed wiring 26 is electrically connected to the
In the figure, only the printed wiring connected to the piezoelectric element 23a is shown), and this printed wiring 26 is connected to the wiring 27 introduced from the outside into the storage space 4. The side surface of the vibrating portion 14, the piezoelectric elements 23a and 23b, the slit 20, the entire protruding portion 21, the printed wiring 26, and a portion of the wiring 27 are covered (molded) with the epoxy resin 25. The surface of the resin 25 that covers the upper surface of the protrusion 21 is polished to be flat. Therefore, the pair of piezoelectric elements 23 a and 23 b are attached and fixed to the lower surface of the vibrating portion 14 of the rotor 15 by the resin 25. Further, the protruding portion 16b of the rotor 15 is placed on the protruding portion 21 via the resin 25.

When an AC voltage having a phase difference of 90 ° is applied to the piezoelectric elements 23a and 23b through the wiring 27 and the printed wiring 26, the piezoelectric elements 23a and 23b
23b expands and contracts to convert electric energy into vibration energy. By this expansion / contraction operation, the protrusion 21 of the vibrating portion 14 vibrates in the vertical and horizontal directions, and a traveling wave traveling in one direction is generated on the protrusion 21. Due to this traveling wave, the rotor 15 rotates in the direction opposite to the direction of the traveling wave, and the output shaft 8 rotates.

Therefore, the pair of piezoelectric elements 23a and 23b are attached and fixed to the lower surface of the vibrating portion 14 of the elastic body 10a while being covered (molded) with the resin 25. As a result, the work of attaching and fixing the pair of piezoelectric elements 23a and 23b to the lower surface of the vibrating portion 14 can be easily performed.
Further, even if the pair of piezoelectric elements 23a and 23b perform expansion / contraction operation, since the pair of piezoelectric elements 23a and 23b are covered with the resin 25, the vibrating portion 14 in the elastic body 10a is covered.
Can be prevented from peeling off from the lower surface.

Further, since the printed wiring 26 and the wiring 27 are also partially covered with the resin 25, the printed wiring 26 is not affected by the external force even if the wiring 27 is subjected to an external force.
It can be prevented from being easily peeled off from 3b.

Further, the upper surface of the protrusion 21 is also covered with the resin 25 which covers the pair of piezoelectric elements 23a and 23b. As a result, the resin 25 present on the upper surface of the protrusion 21
Since the rotor 15 rotates smoothly, it is not necessary to attach a lining material or the like to the rotor 15, and the manufacturing process can be simplified accordingly.

Moreover, since the resin 25 covers the entire vibrating portion 14 including the protrusion 21 provided by the slit 20, it is possible to reliably prevent the resin 25 from peeling off from the vibrating portion 14. .

The present invention is not limited to the above embodiments, but can be carried out as follows. (1) As shown in FIG. 4A, in this another example,
The vibrating portion 1 is formed by applying the resin 25 covering the piezoelectric elements 23a and 23b.
4 is attached only to the side surface. In this case, it is possible to prevent the piezoelectric elements 23a and 23b from being separated from the vibrating portion 14 even when the piezoelectric elements 23a and 23b expand and contract due to the application of the AC voltage. Also, since the resin 25 is cured immediately, the piezoelectric element 2
It is possible to shorten the time for attaching and fixing 3a and 23b to the vibrating portion 14, and to allow the piezoelectric elements 23a and
3b can be easily attached. Furthermore, since the piezoelectric elements 23a and 23b are covered with the resin 25, the step of insulation treatment can be omitted.

(2) As shown in FIG. 4B, in this example, the resin 2 covering the piezoelectric elements 23a and 23b is used.
5 is attached to the side surface of the vibrating portion 14 and poured into the slit 20. In this case, in addition to the effect of the above (1), since the resin 25 is poured into the slit 20, it is possible to prevent the resin 25 from being easily separated from the vibrating portion 14.

(3) As shown in FIGS. 5 and 6, the vibrating section 1
The upper surface of No. 4 is flat so that the protrusion 21 is not integrally formed. The elastic body 10a is formed by pressing. The piezoelectric elements 23a, 23 on the lower surface of the vibrating portion 14 are
b is coated with resin 25. The resin 25 covers the side surface of the vibrating portion 14 and the upper surface of the vibrating portion 14. Then, a slit 31 is formed in the resin 25 of the vibrating portion 14, and the resin 25 forms a protrusion 30 similar to the protrusion 21 of the above-described embodiment.

In this case, since the protrusions 30 are formed of the resin 25, the protrusions 30 can be easily formed, and the stator 10 can be manufactured in a short time. Further, since the protrusion 30 is formed of the resin 25, the step of providing the lining material on the protrusion 16b of the rotor 15 can be omitted. Also, the elastic body 10 formed by pressing
The surface of a is likely to have invisible concavities and convexities, and if the piezoelectric element is attached and fixed with an adhesive as in the conventional case, it is easily peeled off. Therefore, it is possible to prevent peeling. Moreover, since the piezoelectric elements 23a and 23b are covered with the resin 25, the step of insulation treatment can be omitted.

(4) In the above (3), the piezoelectric element 23
Although a and 23b are attached and fixed to the lower surface of the vibrating portion 14, the upper surface of the vibrating portion 14 is also flat. Therefore, as shown in FIG. 7, the piezoelectric elements 23 a and 23 b may be attached to the upper surface of the vibrating portion 14 and covered with the resin 25. In this case as well, it is possible to obtain the same operational effect as the above (3).

(5) As shown in FIGS. 8 and 9, the elastic body 1
0a is formed into a disk shape having a uniform thickness, and a through hole 11 is formed in the center thereof. A plurality of elongated holes 33 penetrating in the thickness direction are radially formed in the elastic body 10a on the outer periphery of the through hole 11. The rigidity of the portion where the long hole 33 is formed is low. Therefore, the portion of the elastic body 10a on the outer periphery of the elongated hole 33 is more likely to vibrate. Then, a pair of piezoelectric elements 23a and 23b forming the stator 10 are arranged on the outer periphery of the elastic body 10a where the elongated holes 33 are formed. The piezoelectric elements 23a and 23b are covered with a resin 25. The resin 25 covers the outer peripheral surface of the elastic body 10a and the outer peripheral surface of the upper surface of the elastic body 10a. A slit 34 is formed in the resin 25 provided on the outer periphery of the upper surface of the elastic body 10a to form a protrusion 35. In this case as well, it is possible to obtain the same operational effect as the above (3). In this example, the pair of piezoelectric elements 23a and 23b are provided on the lower surface of the elastic body 10a, but they may be provided on the upper surface as shown in FIG. Further, as shown in FIG. 11, a pair of piezoelectric elements 23
Alternatively, a and 23b may be formed in an annular shape and provided on both upper and lower surfaces of the elastic body 10a.

(6) In this embodiment, the piezoelectric elements 23a and 23b are completely covered with the resin 25. However, as shown in FIG. 2, the piezoelectric elements 23a and 23b are covered.
It is also possible to form an annular opening 41 in which a part of the lower surface of is exposed.

(7) As shown in FIG. 10, the lining material 42 is formed on the upper surface of the projection 35 formed of the resin 25.
The lining material 42 is provided with the protruding portion 1 of the rotor 15.
You may make it contact 6b. In this case, since the appropriate lining material 42 can be provided on the upper surface of the protrusion 35 by changing the usage environment of the ultrasonic motor, the rotor 15 can be smoothly rotated.
It is also possible to provide this lining material 42 on the upper surface of the resin 25 that covers the upper surface of the protrusion 21.

(8) In this embodiment, epoxy resin is used as the resin 25, but other materials such as polyether ether ketone, polyimide, polyptyrene terephthalate, and polyphenylene sulphide are used. Any material can be used as long as it has excellent high friction characteristics, wear resistance characteristics, and heat resistance characteristics.

[0042]

As described in detail above, according to the first aspect of the present invention, it is possible to prevent the piezoelectric element from being separated from the elastic body even when the piezoelectric element expands or contracts due to the application of the AC voltage.

According to the second aspect of the invention, it is possible to easily form the protrusion on the elastic body with resin. or,
Since the protrusion is made of resin, the rotor can be smoothly rotated. Further, since the resin molds the piezoelectric element and forms the protrusion, it is possible to prevent the piezoelectric element from being further separated from the elastic body.

According to the third aspect of the invention, since the resin molds the piezoelectric element and is poured into the slit of the elastic body, the resin can be securely attached to the stator. Further, even if the piezoelectric element expands and contracts due to the application of the AC voltage, the piezoelectric element can be prevented from being further peeled from the elastic body.

According to the fourth aspect of the invention, the upper surfaces of the piezoelectric element and the protrusion are molded with resin, and the piezoelectric element is attached and fixed to the elastic body. As a result, it is possible to prevent the piezoelectric element from being separated from the elastic body even when the piezoelectric element expands and contracts due to the application of the AC voltage. Further, since the protrusion is molded with resin, the rotor can be smoothly rotated by this resin. Moreover, since the resin molds the upper surfaces of the piezoelectric element and the protrusion, it is possible to prevent the piezoelectric element from further peeling from the elastic body.

According to the fifth aspect of the invention, the lining material can be selected according to the environment of use of the ultrasonic motor, so that the rotor can be smoothly rotated. According to the sixth aspect of the invention, since the piezoelectric element is completely covered with the resin, it is not necessary to perform the insulating treatment of the piezoelectric element in a separate step, and therefore the manufacturing can be facilitated.

[Brief description of drawings]

FIG. 1 is a sectional view of an ultrasonic motor according to the present invention.

FIG. 2 is a sectional view of a stator.

FIG. 3 is a cross-sectional view showing that the entire projection of the stator is also covered with resin.

FIG. 4A is a cross-sectional view showing a state in which only the side surfaces of the piezoelectric element and the vibrating portion are coated with resin, and FIG. 4B is a state in which the side surface of the piezoelectric element and the vibrating portion and the slit are also coated with resin. It is sectional drawing shown.

FIG. 5 is a sectional view of a stator as another example.

FIG. 6 is a cross-sectional view showing another example in which a protrusion is made of resin.

FIG. 7 is a sectional view of a stator showing that a piezoelectric element is provided on the upper surface of a vibrating section.

FIG. 8 is a plan view of a stator as another example.

FIG. 9 is a sectional view of a stator as another example.

FIG. 10 is a sectional view of a stator as another example.

FIG. 11 is a sectional view of a stator as another example.

FIG. 12 is a sectional view of a conventional ultrasonic motor.

[Explanation of symbols]

10 ... Stator, 10a ... Elastic body, 15 ... Rotor, 2
0 ... slits, 21, 30, 35 ... protrusions, 23a, 2
3b ... Piezoelectric element, 25 ... Resin

Claims (6)

[Claims] 1. An ultrasonic motor in which an AC voltage is applied to a piezoelectric element attached to an elastic body to vibrate the stator, and the rotor is brought into contact with the stator by the vibration, and the rotor is rotated. An ultrasonic motor characterized by being molded by and fixed to an elastic body. 2. The ultrasonic motor according to claim 1, wherein a protrusion that comes into contact with the rotor is formed of a resin that fixes the piezoelectric element to an elastic body. 3. A protrusion formed by forming a slit in an elastic body is brought into contact with a rotor, and an AC voltage is applied to a piezoelectric element attached to the elastic body to vibrate the protrusion, and the vibration is generated. In the ultrasonic motor for rotating the rotor that comes into contact with the protrusions, the piezoelectric element is molded with resin to be fixed to the elastic body, and the resin is poured into the slit of the elastic body. 4. A protrusion formed by forming a slit in an elastic body is brought into contact with a rotor, and an AC voltage is applied to a piezoelectric element attached to the elastic body to vibrate the protrusion, and the vibration is generated. In an ultrasonic motor that rotates a rotor that comes into contact with the protrusions, the piezoelectric element is molded with resin to be fixed to an elastic body, and the upper surface of the protrusion formed on the elastic body is covered with resin. And ultrasonic motor. 5. The lining material that comes into contact with the rotor is integrally provided on the upper surface of the protrusion.
The described ultrasonic motor. 6. The ultrasonic motor according to claim 1, wherein the piezoelectric element provided on the elastic body is completely covered with resin.