JP3297162B2 - Vibration motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration motor for rotating a rotor by the vibration of a piezoelectric element.

[0002]

2. Description of the Related Art Conventionally, a bolted Langevin type ultrasonic motor has been known.
A piezoelectric motor using a cantilever torsional ultrasonic vibrator disclosed in Japanese Patent Application Laid-Open No. 70-70, an ultrasonic motor disclosed in Japanese Patent Application Laid-Open No. 63-217984, and the like are known.

[0003] However, conventionally, this kind of motor has a problem that the rotor can rotate only in one direction, and the structure is complicated and expensive.

FIG. 9 is a view showing an example of a conventional bolted Langevin type ultrasonic motor. In the ultrasonic motor shown in the figure, metal blocks 104 and 106 having different lengths are arranged at both ends of two piezoelectric elements 100 and 102. 100 and 102 are fixed so as to be tightened.

In this ultrasonic motor, when a high-frequency AC voltage is applied to the piezoelectric elements 100 and 102 from an AC power supply 110, longitudinal vibrations are generated by vibrations of the piezoelectric elements 100 and 102 in a thickness direction, and torsion is caused by torsion of a bolt 108. Vibration occurs, and an elliptical vibration which combines longitudinal vibration and torsional vibration is generated on the end faces of the block bodies 104 and 106, and a rotational driving force can be obtained by the elliptical vibration.

[0006] A disk 112 is urged toward the block 106 by a spring 114 on the end surface of the block 106 described above, and a rotating shaft 116 of the disk 112 is supported by a bearing 118. I have. Therefore, the disk 112
Is brought into contact with the end face of the block 106, the rotational force obtained by the combined vibration is transmitted to the disk 112, and the rotational output can be taken out from the rotating shaft 116.

The above-mentioned bolted Langevin type ultrasonic motor generates elliptical vibration using torsional vibration generated by bolt tightening, but directly generates elliptical vibration without using bolt tightening. Vibrating motors for driving have been known in the past.
There is a vibration motor according to Japanese Patent Application Laid-Open No. 355679/1993 and Japanese Patent Application Laid-Open No. 146179/1993.

These vibration motors have a piezoelectric element having a plurality of voltage application regions divided in the rotation direction of the rotor, and apply high-frequency AC voltages having different phases to the respective regions. Thereby, bending vibration is directly generated on the metal block body holding the piezoelectric element, and elliptical vibration is generated on the rotor contact surface.

[0009]

However, in the conventional bolt-fastened Langevin type ultrasonic motor shown in FIG. 9, a rotational output cannot be generated effectively unless resonance points of longitudinal vibration and torsional vibration are matched. For this reason, one block body 104 is formed in a short shape, and the other block body 106 is formed.
Must be formed in a long shape so that the resonance points coincide with each other. Moreover, since bolts are used to generate torsional vibration, it is necessary to strictly control the pitch, tightening load, and various dimensional accuracy, and there is a problem that design and manufacturing are difficult.

[0010] Further, since torsional vibration is generated by using bolt tightening, only one-way elliptical vibration can be generated on the end face of the block body 106, and the rotary shaft 116 cannot be driven in both forward and reverse directions. There was a problem.

On the other hand, in a conventional vibration motor in which elliptical vibration is directly generated by bending vibration without using bolt tightening, it is necessary to apply a plurality of high-frequency AC voltages having different phases to each voltage application region in the piezoelectric element. Because
There is a problem that the drive circuit of the motor becomes complicated, which leads to an increase in cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object the purpose of relatively simple dimensional accuracy, easy design and manufacture, and relatively easy change of the rotor rotation direction. And to provide a vibration motor having high rotational efficiency.

[0013]

According to a first aspect of the present invention, there is provided a vibration motor including a stator portion and a rotor portion which is brought into pressure contact with the stator portion. A piezoelectric element that is polarized in the direction of the rotation axis of the rotor portion and directly generates vibration by applying a high-frequency AC voltage to an adjacent electrode; and the piezoelectric element is attached and fixed to both sides of the piezoelectric element so as to sandwich the piezoelectric element. And a plurality of block bodies in which longitudinal vibration is generated by the vibration of the element, at least one of the block bodies ,
Is one or more slit groove even without less is formed, the longitudinal vibration receiving generated indirectly torsional vibration to the block body, the synthesis of the torsional vibration and the longitudinal vibration, the rotor in the stator unit An elliptical vibration is generated on the contact surface with the part, and the rotor part is rotationally driven, and the slit groove is formed.
Is inclined with respect to the rotation axis from the position of the node of the longitudinal vibration.
Extending in both directions along an axis
Depending on the vibration, it differs at the position of the node of the longitudinal vibration
It is characterized by expanding and contracting in the direction .

According to a second aspect of the present invention, in the first aspect of the present invention, the rotational driving direction of the rotor is changed by changing the inclination direction of the slit groove.

Further, the invention of claim 3, any of the invention of claim 1 or 2, wherein the slit groove is formed
The one other block body having no slit groove is assembled to the one block body, and the slit groove is formed at a position including the node of the longitudinal vibration.

[0016]

[Action] piezoelectric element used in the vibration motor according to claim 1, because it is polarized in the direction of the rotation axis of the rotor portion, a plurality of <br/> block body by applying high-frequency AC voltage to the piezoelectric element Longitudinal vibration can be generated. Also,
The inclined slit groove formed in at least one of the block bodies is at a position including the node of the above-described longitudinal vibration. Therefore, when the slit groove portion vibrates longitudinally, the directions of expansion and contraction at the nodes are opposite. Due to this, the longitudinal direction of the slit groove (rotation axis direction)
The length of the slit groove also expands and contracts, and the longitudinal vibration also changes the inclination of the slit groove. As a result, torsional vibration occurs in the slit groove portion. As described above, when the longitudinal vibration and the torsional vibration are generated, an elliptical vibration resulting from the combination of these vibrations is generated on the rotor contact surface of the stator, and the rotor is driven to rotate in one direction.

According to the first aspect of the present invention, since the torsional vibration is generated by forming the slit groove,
In addition, since the torsional vibration is generated using the longitudinal vibration, it is not always necessary to match the resonance points of the independently generated longitudinal vibration and the torsional vibration, and an efficient motor can be easily realized. In addition, since torsional vibration is not generated by using bolt tightening,
There is no need to strictly control the pitch, tightening load, and various dimensional accuracy, and the design and manufacturing are facilitated.

Furthermore, since it is only necessary to apply a single-phase high-frequency AC voltage to the piezoelectric element, the structures of the piezoelectric element and the motor drive circuit are relatively simple, and the cost does not increase.

Further, in the vibration motor according to the second aspect,
By changing the inclination direction of the above-mentioned slit groove, the rotation driving direction of the rotor unit is changed. That is, the torsional vibration generated when the slit groove expands and contracts in the rotation axis direction depends on the inclination direction of the slit groove, and two types of block bodies in which the inclination direction of the slit groove is opposite are prepared. Thus, the rotor unit can be driven to rotate forward or reverse.

In the second aspect of the present invention, it is only necessary to prepare two blocks having different inclination directions of the slit grooves, so that the rotation direction of the rotor portion can be easily changed.

In particular, in the conventional bolt-fastened Langevin type ultrasonic motor, the rotation direction cannot be changed unless the bolt is changed, whereas in the present invention, only the block body needs to be changed. Can be easily shared, and in that sense, the cost can be reduced.

Further, in the invention of claim 3, either
One simply cutting the end of the Tsunobu lock body can form a slit groove as described above, it is easy to manufacture.

[0023]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the entire configuration of an embodiment to which the vibration motor of the present invention is applied.

The vibration motor of the present embodiment shown in FIG.
And a stator portion 20 that is driven to rotate by elliptical vibration generated on the rotor contact surface 12 as one end surface. The rotor unit 10 includes a disk 14 that contacts the rotor contact surface 12 with a constant pressure, and a rotation output shaft 16 attached to the center of rotation of the disk 14. Therefore, when the elliptical vibration occurs on the rotor contact surface 12 of the stator section 20, the disk 14 of the rotor section 10
Is driven to rotate in one direction.

The stator section 20 includes piezoelectric elements 22 and 24 formed in a ring shape by using a piezoelectric material such as ceramics, and electrodes arranged on both sides of one of the piezoelectric elements 24 so as to contact the entire surface. Plates 26, 28, and a first metal block 30, a second metal block 32, and a third metal block 30 arranged to sandwich the piezoelectric element 22, the electrode plate 26, the piezoelectric element 24, and the electrode plate 28 from both sides. And a connecting bolt 36 for fastening and fixing the first metal block 30 and the third metal block 34 located at both ends.

One end face of the third metal block body 34 is the rotor contact surface 12 described above, while the other end face is in contact with the second metal block 32, and the other end face has an end portion. A plurality of oblique slit grooves 38 are formed so as to match. Therefore, after assembling the stator section 20, the second metal block body 32 and the third metal block body 34 are integrated, and a plurality of oblique slit grooves 38 are formed substantially near the center thereof. .

The above-mentioned piezoelectric elements 22 and 24 are used as electrodes during polarization, for example, those obtained by polishing and removing silver and nickel surfaces after the completion of polarization.

FIG. 2 is a perspective view showing a state where the stator section 20 is assembled. As shown in the figure, the assembled stator portion 20 includes a third metal block body 34 and a second metal block body 34.
Has a structure in which the metal block body 32, the piezoelectric element 22, the electrode plate 26, the piezoelectric element 24, the electrode plate 28, and the first metal block body 30 are connected and integrated. The external connection terminal 40 has a shape in which the external connection terminal 42 projects from the other electrode plate 28.

The two external connection terminals 40 and 42 are for applying a high frequency AC voltage having a constant frequency to the piezoelectric element 24. Further, with respect to the other piezoelectric element 22, the end face of the second metal block 32 electrically connected to the external connection terminal 42 via the coupling bolt 36 shown in FIG. 1 acts as an electrode plate. A high frequency AC voltage having a constant frequency is applied by the second metal block 32 and the external connection terminal 40.

FIG. 3 is an exploded perspective view showing the detailed structure and the assembled state of the stator section 20.

A screw hole is formed at the center of each of the first metal block 30 and the third metal block 34 so that a male screw groove formed in the coupling bolt 36 is screwed. Has become. In the center of the second metal block body 32, a bolt insertion hole 32a having an inner diameter substantially equal to the outer diameter of the coupling bolt 36 is formed. Each of the piezoelectric element 22, the electrode plate 26, the piezoelectric element 24, and the electrode plate 28 has a bolt insertion hole 22a, 26a, 24a, having an inner diameter larger than the outer diameter of the coupling bolt 36.
28a are formed. These bolt insertion holes 22
a, 26a, 24a, 28a have inner diameters of the piezoelectric elements 22,
When the electrode plate 26, the piezoelectric element 24, and the electrode plate 28 are assembled, the outer diameter of the collar 44 is substantially equal to the outer diameter of the collar 44 inserted outside the coupling bolt 36.

To assemble the stator portion 20, first, one end of a connecting bolt 36 is screwed and fixed to the first metal block body 30, and then the collar 44 is inserted. Each of the plate 28, the piezoelectric element 24, the electrode plate 26, and the piezoelectric element 22 is inserted sequentially. Next, the second metal block 32 is inserted into the connecting bolt 36, and finally, the third metal block 34 is connected to the connecting bolt 36.
The other members are fastened and fixed by the first and third metal block bodies 30 and 34 by screwing into the other end of.

In the present embodiment, when this connection and fixing is performed,
Since no adhesive is used to fix the laminated surface of each member, it is possible to prevent variations in the resonance frequency of each motor and a decrease in the Q value, thereby improving the performance and reliability of the vibration motor. it can.

As shown in FIG. 3, the piezoelectric elements 22 and 24 are arranged so that their polarization directions are different, and when high-frequency AC voltages of the same polarity are applied, when one expands, the other contracts. become. However, since the high frequency AC voltage of the opposite polarity is applied by using the electrode plate 26 in common, when one piezoelectric element 22 is extended, the other piezoelectric element 24
When one piezoelectric element 22 contracts, the other piezoelectric element also contracts. Accordingly, the amplitude value in the vertical direction (the longitudinal direction of the coupling bolt 36) of the entire stator portion 20 can be set to be large.

FIG. 4 is a view showing details of the oblique slit groove 38 formed in the third metal block body 34 of the stator section 20. FIG. 6A is a view of the third metal block body 34 viewed from the side, and shows a plurality of oblique slit grooves 3.
8 shows a state in which 8 is arranged so as to partially contact the lower end surface of the third metal block body 34. Since these oblique slit grooves 38 can be formed by cutting from the lower side or the lateral direction of the third metal block body 34, the formation can be performed relatively easily. Although the second and third metal blocks 32 and 34 are formed of a single metal block, and a blade is inserted in the vicinity of the middle between the second and third metal blocks 32 and 34, the oblique slit groove 38 is formed. You may do so.

FIG. 3B is a view of the third metal block body 34 as viewed from below.
A state in which twelve oblique slit grooves 38 are formed in a 5-mm metal block body 34 is shown.

FIG. 5 is a view for explaining the vertical position of the oblique slit groove 38, that is, the position in the direction of the rotation axis of the rotor.

As shown in FIG. 5A, the oblique slit groove 38 is formed so that the center thereof coincides with the position of the node of the longitudinal vibration shown in FIG. FIG. 4B shows the positions of the nodes and antinodes of the longitudinal vibration, and the positions of the nodes and antinodes in the figure correspond to the positions of the antinodes, respectively, and both end surfaces of the stator portion 20 correspond to the positions of the antinodes. Then, the other node is connected to the piezoelectric element 2 so that one node is located at the center of the oblique slit groove 38.
2 and 24, respectively.

As described above, by making the center of the oblique slit groove 38 coincide with the position of the node of the longitudinal vibration, the oblique slit groove 38 expands and contracts in different directions with the center as a boundary. In addition, since the inclination direction of the oblique slit groove 38 is different from the vibration direction of the vertical vibration, when such expansion and contraction occurs, a phenomenon occurs in which the rotation is performed in a direction in which the center portion rotates as a rotation center within a certain angle range. . As a result, vibration in the torsional direction is generated in the oblique slit groove 38 portion of the third metal block body 34, and this vibration propagates to the other metal block bodies 30 and 32.
Will cause torsional vibration. Therefore, the longitudinal vibration directly generated by the piezoelectric elements 22 and 24 and the torsional vibration generated by the action of the oblique slit groove 38 are combined, and an elliptical vibration in a certain direction is generated on the rotor contact surface 12, and the elliptical vibration is generated. Accordingly, the rotor unit 10 is driven to rotate in one direction.

FIG. 5C schematically shows the torsional vibration generated in the stator section 20. The frequency of the high-frequency AC voltage applied to the piezoelectric elements 22 and 24 is changed so that the torsional vibration is generated at the resonance frequency. It is desirable to decide. However, in general, the resonance frequency also differs depending on the difference between the longitudinal elastic modulus and the transverse elastic coefficient. Accordingly, longitudinal vibration and torsional vibration of the same order do not occur due to the resonance frequency of the same frequency. When the piezoelectric elements 22 and 24 are vibrated by the resonance frequency of a certain frequency, longitudinal vibration and torsional vibration of different resonance orders occur. Thus, the frequency of the high-frequency AC voltage must be set.

For example, three metal blocks 30, 3
The primary resonance frequency of the longitudinal vibration when the diameter of the stator portion 20 is 35 mm and the length L is 90 mm (the lengths of the piezoelectric elements 22 and 24 are also converted to aluminum) while forming the portions 2 and 34 from aluminum. When each of f01 and the secondary resonance frequency f02 is calculated,

(Equation 1) When the primary resonance frequency f11, the secondary resonance frequency f12, and the tertiary resonance frequency f13 of the torsional vibration are calculated,

(Equation 2) Here, v0 and v1 are the propagation velocities of the vertical and horizontal vibrations of the metal block body 30 and the like, respectively, and were calculated as 5100 m / s and 3000 m / s, respectively.

As described above, the resonance frequency is different between the longitudinal vibration and the torsional vibration. For example, the secondary resonance frequency of the longitudinal vibration and the tertiary resonance frequency of the torsional vibration are each 56 k.
Hz and 51 kHz, which are relatively close. Therefore, in this embodiment, 50 kHz is used as the frequency of the high-frequency AC voltage so that both longitudinal vibration and torsional vibration resonate at the same frequency.

Actually, when a vibration motor having the above-described design values was experimentally manufactured and confirmed by the present applicant, it was confirmed that elliptical vibration was generated on the rotor contact surface 12 and the rotor portion 10 could be driven to rotate in one direction. Have been. Moreover,
Compared with the conventional bolted Langevin type vibration motor, the generated driving torque is about 5 to 10 times larger,
It has been confirmed that the rotation efficiency is also good. At this time, the width of the oblique slit groove 38 was 2 mm, and the length in the rotation axis direction of the rotor was 7 mm.

The direction of rotation of the rotor section 10 can be reversed by reversing the direction of inclination of the oblique slit groove 38. For example, when the oblique slit groove 38 is formed in the inclination direction shown in FIG. 5 and the vibration motor rotates in the secondary resonance mode for the longitudinal vibration and the tertiary resonance mode for the torsional vibration, the rotor unit 10 rotates clockwise. It is driven to rotate in the direction. On the other hand, when the inclined direction is set to the opposite direction while the shape of the oblique slit groove 38 is kept substantially the same, it has been confirmed that the rotor unit 10 is driven to rotate in the counterclockwise direction. The rotation direction of the rotor unit 10 can be set only by the inclination direction of 38.

Thus, if two types of the third metal block bodies 34 having the oblique slit grooves 38 having the opposite inclination directions are prepared, the rotation direction of the motor is set to be opposite depending on which one is used. Therefore, the effect of reducing the manufacturing cost by sharing the parts becomes large. This is a clear difference in comparison with the case of the conventional bolted Langevin type motor in which both the connecting bolt and the two metal blocks had to be replaced.

Further, in the vibration motor of this embodiment,
Elliptical vibration also occurs on the stator end surface opposite to the rotor contact surface 12. That is, since elliptical vibration also occurs at the lower end surface shown in FIG. 5, by using this end surface as the rotor contact surface 46, a vibration motor that simultaneously rotates and drives two rotor units can be provided.

In the case of the vibration mode and the inclined direction of the oblique slit groove 38 shown in FIG. 5, the rotor portion 10 in contact with the rotor contact surface 12 is driven to rotate clockwise while the other rotor contact surface 46 is rotated. Is driven to rotate counterclockwise. When the inclined direction of the oblique slit groove 38 is reversed, the rotor portion 10 in contact with the rotor contact surface 12 is driven to rotate counterclockwise, and at the same time, the rotor portion 10 in contact with the other rotor contact surface 46 is rotated. Is driven to rotate clockwise.
Note that by changing the resonance mode, the two rotor units can be driven to rotate in the same direction, and the combination of the rotation directions can be set as needed.

As described above, in the vibration motor of this embodiment, the torsional vibration is generated simultaneously with the vertical vibration by forming the oblique slit groove 38 so that the center is located at the node of the vertical vibration. Since it is not always necessary to match the resonance points of the longitudinal vibration and the torsional vibration, an efficient motor can be easily realized.

Further, since the connecting bolt 36 is used only for tightening the first and third metal block bodies 30 and 34, it is not necessary to strictly control the pitch, the tightening load and various dimensional accuracy, so that the design and the manufacture are possible. Becomes easier.

Further, since the entirety of the piezoelectric elements 22 and 24 is merely polarized in the same direction, the piezoelectric elements and the motor drive circuit can be operated by applying a single-phase high-frequency AC voltage. Is relatively simple and does not cause an increase in cost.

FIG. 6 is a view showing the structure of a vibration motor in which the connecting bolt 36 is replaced by another member. Coupling bolt 3
6 is simply screwed into the first and third metal block bodies 30 and 34 as shown in FIG.
The metal block 32, the piezoelectric element 22, the electrode plate 26, the piezoelectric element 24, and the electrode plate 28 are merely tightened from both sides. Therefore, any member other than the connection bolt 36 may be used as long as it can be similarly fastened, and there is no need to screw the metal block 30 or 34 into engagement.

FIG. 6A shows one connecting bolt 48 and 2
A vibration motor that performs the above-described tightening by two nuts 50 and 52 is shown. In this case, through holes are formed in the first and third metal block bodies 30 and 34, and each metal block body 30 and 34 is
Tighten by 0,52.

As described above, without forming the screw holes in the first and third metal block bodies 30, 34, the connecting bolt 48 is formed.
By tightening each member with the two nuts 50 and 52, the distortion generated in the metal block bodies 30 and 34 can be minimized. That is, when screw holes are formed in the metal block bodies 30 and 34 and these screw holes are screwed into the connecting bolts 36 to perform overall tightening, local stress acts near the screw holes. , Complicated distortion occurs. On the other hand, when the nuts 50 and 52 are tightened from the outside of the metal block bodies 30 and 34, a substantially uniform tightening stress acts from the outside to the inside and acts on the metal block bodies 30 and 34. The resulting stress is relatively simple and the resulting strain is not complicated. Therefore, stable output characteristics can be easily obtained.

FIGS. 6B and 6C show a case where the above-described tightening is performed by using a connecting rod 54 instead of the connecting bolt 48 and caulking one end thereof. After each component is inserted into the connecting rod 54 in order, one end thereof is swaged as shown in FIG.

As described above, the vibration motor according to the present embodiment does not generate torsional vibration using the tightening by bolts. Therefore, any method may be used for tightening each member. Therefore, as shown in FIG. 6, it is only necessary to use commonly used nuts 50 and 52 or to simply caulk the connecting rod 54, thereby reducing the cost of parts and simplifying the manufacturing process. You can also.

FIG. 7 is a view showing another embodiment of the present invention, and is an exploded perspective view of the stator section 20 corresponding to FIG. This vibration motor has a structure in which one piezoelectric element 22 in the vibration motor shown in FIG. In the vibration motor shown in FIG. 3, two piezoelectric elements 2 are used to increase the amplitude of the longitudinal vibration.
Although a large amplitude, that is, a large driving force is not necessarily required depending on the application, the vibration motor shown in FIG. 7 is used when a small driving force is sufficient. Since this vibration motor generates longitudinal vibration only by the piezoelectric element 24, the rotational driving force is about half of that of the vibration motor shown in FIG.

The structure shown in FIG. 1 can be applied to the rotor section 10 and its assembled state.

FIG. 8 is a diagram showing another embodiment of the present invention. FIG. 1A is a side view of the stator unit 20, and FIG. 1B is a cross-sectional view taken along line AA.

The feature of the vibration motor of the present embodiment is that a plurality of vertical slit grooves 58 are formed in the second metal block 32. The vertical slit groove 58 is preferably formed so as not to be located at the node of the longitudinal vibration and the torsional vibration. For example, in the example shown in FIG. 5, the longitudinal slit groove 58 is formed so as to be located between the node of the longitudinal vibration and the node of the torsional vibration.

By forming the vertical slit groove 58 in a part of the metal block body 32, the weight is reduced at the portion where the vertical slit groove 58 is formed. An enlarged and larger elliptical vibration will occur on the rotor contact surface 12.
Therefore, the rotor portion 10 in contact with the rotor contact surface 12
Is driven to rotate with a larger driving force.

The vertical slit groove 58 also has a function of improving the heat radiation effect together with the above-described oblique slit groove 38. In particular, since the vibration motor has a problem of low heat radiation performance, the provision of the slit groove has a great effect of improving the heat radiation.

The number of the vertical slit grooves 58 formed in the second metal block body 32 is not limited to eight, but may be one or more. Further, in the example shown in FIG. 8, it is formed so as not to cover the nodes of the longitudinal vibration and the torsional vibration, but it may be formed including the positions of the nodes. When the vertical slit groove 58 is divided and formed, or when the first and third metal block bodies 30 and
34, and the like.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

For example, in the above-described embodiment, the case where the diagonal slit groove 38 is formed at the position of one node of the longitudinal vibration has been described as an example. An oblique slit groove 38 may be formed in each of the above nodes. In this case, it is necessary to determine the inclination direction so that the oblique slit grooves 38 formed at the positions of the respective nodes amplify the torsional vibration with each other.

[0066]

As described above, according to the first aspect of the present invention,
Since torsional vibration is generated by forming slit grooves, and this torsional vibration is generated using longitudinal vibration, it is not always necessary to match the resonance points of longitudinal vibration and torsional vibration generated independently. Therefore, an efficient motor can be easily realized. Further, since the torsional vibration is not generated by using the tightening with the bolt, it is not necessary to strictly control the pitch, the tightening load and various dimensional accuracy, and the design and the manufacture are facilitated.
Furthermore, since it is only necessary to apply a single-phase high-frequency AC voltage to the piezoelectric element, the structures of the piezoelectric element and the motor drive circuit are relatively simple, and the cost does not increase.

According to the second aspect of the present invention, the rotation direction of the rotor can be easily changed only by preparing two blocks having different inclination directions of the slit grooves.
Other components can be easily shared, and the cost can be reduced.

[0068] According to the invention of claim 3, or
Since the above-mentioned slit groove can be formed only by cutting the end of one block body, the manufacture becomes easy.

[Brief description of the drawings]

FIG. 1 is a diagram showing an entire configuration of an embodiment to which a vibration motor of the present invention is applied.

FIG. 2 is a perspective view showing a state where the stator unit shown in FIG. 1 is assembled.

FIG. 3 is an exploded perspective view showing a detailed structure and an assembled state of a stator unit.

FIG. 4 is a diagram showing details of an oblique slit groove formed in a third metal block body of a stator portion.

FIG. 5 is a view for explaining a vertical position of an oblique slit groove.

FIG. 6 is a view showing a structure of a vibration motor in which the coupling bolt shown in FIG. 3 is replaced with another member.

FIG. 7 is a diagram showing another embodiment of the present invention.

FIG. 8 is a diagram showing another embodiment of the present invention.

FIG. 9 is a view showing an example of a conventional bolted Langevin type ultrasonic motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rotor part 20 Stator part 22, 24 Piezoelectric element 26, 28 Electrode plate 30 1st metal block body 32 2nd metal block body 34 3rd metal block body 36 Coupling bolt 38 Oblique slit groove

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshiaki Miyamoto 20 Oyamazuka, Oiwa-cho, Toyohashi-shi, Aichi Honda Electronics Co., Ltd. (56) References JP-A-2-26281 (JP, A) JP-A JP-A-5-122961 (JP, A) JP-A-55-145573 (JP, A) JP-A-5-168263 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02N 2 / 00

Claims (3)

(57) [Claims] 1. A vibration motor comprising a stator section and a rotor section which is brought into pressure contact with said stator section, wherein said stator section is polarized in a direction of a rotation axis of said rotor section, and a high-frequency alternating current to an adjacent electrode is provided. A piezoelectric element that directly generates vibration by application of a voltage, and a plurality of block bodies that are attached and fixed to both sides of the piezoelectric element so as to sandwich the piezoelectric element, and that generate longitudinal vibration due to the vibration of the piezoelectric element. Does one of said block body being formed has one or more slit grooves with little no <br/>, the longitudinal vibration receiving generated indirectly torsional vibration to the block body, the said longitudinal vibration the combination of the torsional vibration, the elliptical vibration is generated on the contact surface between the rotor part in the stator part, and rotationally drives the rotor portion, the slit grooves, position of node of the longitudinal vibration The rotation from
Formed to extend in both directions along an axis that is inclined with respect to the axis
The position of the node of the longitudinal vibration is determined by the longitudinal vibration.
A vibration motor characterized in that it expands and contracts in different directions as boundaries . 2. The vibration motor according to claim 1, wherein a rotation driving direction of the rotor is changed by changing an inclination direction of the slit groove. 3. The longitudinal vibration device according to claim 1, wherein one of the block members having the slit groove is attached to one of the block members having no slit groove. A vibration motor, wherein the slit groove is formed at a position including a node.