JP2013143827A - Vibration actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration actuator capable of stably obtaining large torque irrespective of its small structure.SOLUTION: There is provided a vibration actuator 10 including: a stator 13; a roller 30 supported by the stator 13 in contact; a rotary shaft 34 supporting the roller 30 rotatably; vibration means coupled to the stator 13 and rotating the roller 30 by causing ultrasonic vibrations at a contact part between the stator 13 and roller 30; and pre-load means coupled to the rotary shaft 34, and pressing the roller 30 against the stator 13 by energizing the rotary shaft 34 against the stator 13. The pre-load means includes a coupling member 37 having a pair of coupling parts 38 coupled to the rotary shaft 34 on both sides of the roller 30, and the stator 13 includes a space part for housing the coupling member 37.

Description

  The present invention relates to a vibration actuator, and more particularly to a vibration actuator that rotates a rotating body using ultrasonic vibration.

As a conventional technique of the vibration actuator, for example, an ultrasonic motor disclosed in Patent Document 1 can be cited.
The ultrasonic motor disclosed in Patent Document 1 includes a piezoelectric vibrator, a vibration expanding member provided on the bottom surface of the piezoelectric vibrator, and a low elastic modulus member provided on the top surface of the piezoelectric vibrator.
A guide case is disposed around the piezoelectric vibrator, a pressure member is provided on the upper surface of the guide case, and a guide plate is provided in which side portions of the guide case are fitted.
In the ultrasonic motor, the tip of the vibration expansion protrusion is in pressure contact with the moving body.

According to this ultrasonic motor, the guide case guides only in the pressurizing direction without moving the piezoelectric vibrator in the direction perpendicular to the pressurizing direction even with respect to the bending vibration and the stretching vibration of the piezoelectric vibrator. .
Accordingly, the pressure contact portion of the piezoelectric vibrator with the moving body does not slip, so that a large pressure is applied between the vibration expanding member provided at the pressure contact portion of the piezoelectric vibrator and the moving body, generating a large torque and torque. Is going to stabilize.

JP 2007-189899 A

  However, although the ultrasonic motor disclosed in Patent Document 1 generates a large torque and stabilizes the torque, the guide case is arranged around the piezoelectric vibrator. There is a problem that the physique grows.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a vibration actuator that can stably obtain a large torque even if the physique is small.

  In order to solve the above-described problems, the present invention provides a stator, a roller that is contacted and supported by the stator, a rotating shaft that rotatably supports the roller, and the stator and the roller that are coupled to the stator. Vibration means for rotating the roller by generating ultrasonic vibration at a contact portion thereof, and the roller is applied to the stator by urging the rotation shaft toward the stator connected to the rotation shaft. In the vibration actuator including the preload means for compressing, the preload means includes a connecting member having a pair of connecting portions connected to the rotating shaft on both sides of the roller, and the stator houses the connecting member. A space portion is provided.

According to the present invention, the connecting member constituting a part of the preload means is accommodated in the space inside the stator, and the size of the vibration actuator can be reduced.
Further, since the connecting member does not hinder the vibration of the vibration means, a large torque can be stably obtained even if the physique is small.

In the vibration actuator, the preload means penetrates the stator and the vibration means, is connected to the connecting member, is connected to the rod, and the rotation shaft is directed to the stator. It is good also as a structure provided with the urging | biasing member urged by.
In this case, since the connecting rod penetrates the inside of the vibration means, it is not necessary to provide the rod outside the vibration means, and the size of the vibration actuator can be further reduced.

In the vibration actuator, the roller may be single.
In this case, machining accuracy is improved by using a single roller, and there is no variation in assembly accuracy that occurs when a plurality of rollers are assembled. Therefore, the vibration actuator can obtain more stable torque.

In the vibration actuator, a case member connected to the stator may be provided, and the case member may include a space for accommodating the biasing member.
In this case, the urging member can be accommodated in the space of the case member, and there is no need to provide the urging member outside.
For this reason, the size of the vibration actuator can be further reduced.

In the vibration actuator, the connecting member may have a fixing portion for fixing.
In this case, the vibration actuator can be fixed to the fixing destination via the fixing portion.
Even in a state where the vibration actuator is fixed, the connecting member to be fixed can stably obtain a large torque even if it is small in size without hindering the vibration of the vibration means.

In the vibration actuator, the connecting member may include a facing surface that faces an outer peripheral surface of the roller, and a lubricating member including a lubricant may be installed on the facing surface.
In this case, a lubricant that promotes lubrication between the roller and the stator can be supplied to the roller by installing the lubricating member on the opposing surface of the connecting member.
Since the lubricating member is surrounded by the roller, the stator and the connecting member, it does not fall off, and means for fixing the lubricating member to the connecting member becomes unnecessary.

  According to the present invention, it is possible to provide a vibration actuator capable of stably obtaining a large torque even when the physique is small.

It is a perspective view of the vibration actuator concerning a 1st embodiment. It is a side view of the vibration actuator which concerns on 1st Embodiment. It is an arrow view of the AA line of FIG. It is a disassembled perspective view of the principal part of the vibration actuator which concerns on 1st Embodiment. It is a side view of the vibration actuator which concerns on 2nd Embodiment. It is an arrow view of the BB line of FIG. It is a side view of the vibration actuator which concerns on a modification.

(First embodiment)
The vibration actuator according to the first embodiment will be described below with reference to the drawings.
A vibration actuator 10 shown in FIG. 1 is an ultrasonic actuator that rotates a rotating body using ultrasonic vibration.
As shown in FIG. 1, the vibration actuator 10 includes a cylindrical base 11, a stator 13, a piezoelectric element 17, a roller 30 having a rotating shaft 34, a connecting member 37 connected to the rotating shaft 34, A disc spring 50 as an urging member is provided.
As shown in FIG. 1, the roller 30 is composed of a single member.

As shown in FIG. 2, the base portion 11 is cylindrical, and a screw hole 12 is formed at the center of the base portion 11, and the base portion 11 is connected to the stator 13.
The stator 13 includes a shaft portion 14 that can be screwed into the screw hole 12 and a columnar stator main body portion 15 formed on the proximal end side of the shaft portion 14.
A male screw 16 corresponding to the screw hole 12 is formed near the tip of the shaft portion 14.

Between the base 11 and the stator main body 15, a piezoelectric element 17 is provided as vibration means.
The piezoelectric element 17 has a substantially cylindrical shape and has a through hole 18 at the center.
By inserting the shaft portion 14 of the stator 13 into the through hole 18 of the piezoelectric element 17, the piezoelectric element 17 is held by the stator 13.
The piezoelectric element 17 has a structure in which perforated disk-shaped piezoelectric element plates (not shown) that are electrically connected to a drive circuit (not shown) are stacked.
The plurality of piezoelectric element plates constituting the piezoelectric element 17 generate ultrasonic vibrations when an AC voltage is applied from the drive circuit.

A cylindrical stator main body 15 that contacts and supports the roller 30 is provided on the proximal end side of the shaft portion 14.
At the end of the stator main body 15 on the roller 30 side, a groove 19 is formed that crosses in the radial direction.
The groove part 19 forms a space part in which a part of the connecting member 37 connected to the rotating shaft 34 is accommodated.
On both sides of the groove portion 19 in the stator main body portion 15, a contact portion 20 having a contact surface 21 that contacts the outer peripheral surface 31 of the roller 30 is formed.
The contact surface 21 corresponds to a contact portion with the roller 30.
The stator 13 has a through hole 22 that passes through the centers of the shaft portion 14 and the stator main body portion 15.

As shown in FIG. 3, the roller 30 includes an outer peripheral surface 31 and a pair of roller end surfaces 32, and a shaft hole 33 is formed at the center of the roller 30.
A rotation shaft 34 passes through the shaft hole 33 of the roller 30, and the rotation shaft 34 is fixed to the roller 30.
Thus, when the rotating shaft 34 penetrates the roller 30, the rotating shaft 34 rotatably supports the roller.
Although not shown, the rotating shaft 34 is fixed to the roller 30 using a set screw, a key, or the like.
The axis of the rotation shaft 34 is the rotation axis P of the roller 30.
The outer peripheral surface 31 of the roller 30 is formed on a surface having the same curvature as that of the contact surface 21 of the contact portion 20 in the stator 13.
In the present embodiment, both end portions of the rotating shaft 34 are output ends of the vibration actuator 10, and the rotational force of the rotating shaft 34 is used as an output.

The rotating shaft 34 is connected to a connecting member 37 via bearings 36 on both sides of the roller end surface 32.
As shown in FIG. 3, the connecting member 37 is substantially U-shaped when viewed from the front, and includes a pair of connecting portions 38 and a connecting portion 39 that connects the pair of connecting portions 38.
A through hole 40 is formed in the connecting portion 38, the rotating shaft 34 is inserted through the through hole 40, and the rotating shaft 34 is supported by the connecting portion 38 via a bearing 36.
A portion of the connecting portion 39 and the connecting portion 38 near the connecting portion 39 is a groove inserting portion that is inserted into the groove portion 19 of the stator 13 with almost no gap. The groove inserting portion is set to a dimension corresponding to the width of the groove portion 19. Yes.
Incidentally, in this embodiment, the dimension of the connecting member 37 corresponding to the direction of the rotation axis P substantially corresponds to the groove length of the groove portion 19 of the stator main body portion 15, and the connecting member 37 inserted into the groove portion 19 is It only needs to protrude slightly from the groove portion 19.

In the present embodiment, a gap is formed between the outer peripheral surface 31 of the roller 30 and the connecting portion 39 of the connecting member 37, and a sponge body 41 containing lubricating oil as a lubricant is accommodated in this gap. Yes.
The sponge body 41 corresponds to a lubricating member, and is used for supplying lubricating oil to the outer peripheral surface 31 of the roller 30.
The sponge body 41 is placed on the surface of the connecting portion 39 between the connecting portions 38 and is not fixed to the connecting member 37.
The surface of the connecting portion 39 between the connecting portions 38 corresponds to a facing surface facing the outer peripheral surface 31 with the roller 30.
In a state where the connecting member 37 is inserted into the groove portion 19 of the stator 13, the periphery of the sponge body 41 is covered with the stator 13, the roller 30, and the connecting member 37, and the sponge body 41 does not fall out of the space portion.

The connecting member 37 is connected to the connecting rod 45.
A screw hole 42 is formed in the center of the connecting portion 39 of the connecting member 37.
A screw shaft portion 46 corresponding to the screw hole 42 is formed at one end portion of the connecting rod 45.
When the screw shaft portion 46 of the connecting rod 45 is screwed into the screw hole 42, the connecting rod 45 and the connecting member 37 are connected to each other.
The connecting rod 45 is inserted into the through hole 22 of the stator 13, and the other end of the connecting rod 45 protrudes from the shaft portion 14 of the stator 13.
Accordingly, the connecting rod 45 passes through the stator 13 and the piezoelectric element 17.
A disc-shaped spring receiver 49 is attached to a protruding end 47 protruding from the shaft portion 14 of the connecting rod 45 via a holder 48.
A disc spring 50 as an urging member is interposed between the spring receiver 49 and the base portion 11.

The disc spring 50 has a spring force that opposes the force acting in the direction in which the outer diameter edge and the inner diameter edge of the disc spring 50 approach each other, and the spring force acts on the connecting rod 45 as an urging force that brings the rotating shaft 34 closer to the stator 13. Is granted.
The rotating shaft 34 is urged toward the stator 13 via the connecting member 37 by the urging force of the disc spring 50, so that the roller 30 is pressed against the stator 13.
In the present embodiment, the connecting rod 45, the spring receiver 49, and the disc spring 50 are elements constituting the preload means.
Here, for convenience of explanation, the axial direction of the connecting rod 45 is defined as the Z axis, the X axis is directed in the direction perpendicular to the Z axis, and the Y axis perpendicular to the Z axis and the X axis is set. It shall be.

FIG. 4 is an exploded perspective view of the vibration actuator 10, and shows the base 11, the stator 13, the piezoelectric element 17, the roller 30, the connecting member 37, and the disc spring 50 in an exploded manner.
In FIG. 4, the connecting rod 45 is connected to the connecting member 37, and the protruding end 47, the holder 48, and the spring receiver 49 are not shown.

Next, the operation of the vibration actuator 10 according to this embodiment will be described.
When an AC voltage is applied to each piezoelectric element plate of the piezoelectric element 17 by the drive circuit, each piezoelectric element plate generates ultrasonic vibrations having different vibration directions.
By applying an alternating voltage whose phase is shifted by 90 degrees to the piezoelectric element 17, a combined motion in which the Y-axis deflection vibration and the Z-axis direction longitudinal vibration are combined is generated in the piezoelectric element 17.
The composite vibration of the ultrasonic vibration is transmitted to the stator 13, and an elliptical motion (or circular motion) around the X axis in the Y-axis / Z-axis plane occurs on the pair of contact surfaces 21 in the stator 13.
When the roller 30 receives an elliptical motion (or a circular motion) through the contact surface 21, the roller 30 is rotated about the rotation shaft 34.
By the rotation of the roller 30, a rotational force is obtained as an output at the end of the rotation shaft 34 fixed to the roller 30.
The rotation direction, rotation speed, and torque of the roller 30 can be controlled by controlling the applied AC voltage, frequency, and the like.

Since the connecting member 37 is urged by the connecting rod 45 receiving the urging force of the disc spring 50 in the direction approaching the stator 13, the roller 30 is pressed against the stator 13.
Since the roller 30 is in pressure contact with the stator 13 by the urging of the rotating shaft 34 toward the stator 13 by the preloading means, the load due to the pressure contact of the roller 30 acts on the contact surface 21 of the stator 13 equally. The roller 30 is rotated with high torque.
Since the roller 30 and the stator 13 are pressed against each other, the connecting member 37 does not prevent the vibrating stator 13 and the piezoelectric element 17 from vibrating.
For this reason, if a fixed portion for fixing to the installation destination is set in the connecting member 37 and the vibration actuator 10 is fixed to the installation destination via the fixing portion, the fixed vibration actuator 10 is connected to the stator 13 or the piezoelectric element 17. Operates without disturbing vibration.
In the present embodiment, it is preferable that a part of the connecting portion 38 of the connecting member 37 is a fixed portion.

During the rotation of the roller 30, the lubricant oil of the sponge body 41 is applied to the outer peripheral surface 31 of the roller 30, and the pressure contact state between the outer peripheral surface 31 of the roller 30 and the contact surface 21 of the stator 13 by the lubricant is high. The torque torque can be obtained.
That is, the lubricating oil maintains an appropriate pressure contact state between the outer peripheral surface 31 of the roller 30 and the contact surface 21 of the stator 13.

The vibration actuator 10 of this embodiment has the following effects.
(1) Since the groove insertion portion of the connecting member 37 constituting a part of the preload means is accommodated in the space portion of the groove portion 19 of the stator 13, the size of the vibration actuator 10 can be reduced. In particular, the connecting member 37 does not protrude greatly from the stator 13 in the radial direction of the stator 13, and the physique of the vibration actuator 10 can be further reduced.
(2) Since the connecting member 37 does not hinder the vibration of the stator 13 and the piezoelectric element 17, the rotating roller 30 can stably obtain a large torque even if the physique is small.
(3) Since the connecting member 37 is connected to the rotating shaft 34 on both sides of the roller 30 and is biased by the connecting rod 45 that receives the biasing force, the load due to the pressure contact of the roller 30 on the pair of contact surfaces 21 of the stator 13 Can be applied equally.
(4) Since the connecting rod 45 penetrates the stator 13 and the piezoelectric element 17, it is not necessary to provide the connecting rod outside the stator 13 and the piezoelectric element 17, and the size of the vibration actuator 10 can be further reduced. .
(5) By using the roller 30 as a single member, the processing accuracy is improved, and there is no variation in assembly accuracy that occurs when a plurality of rollers are assembled. Therefore, the vibration actuator 10 can obtain more stable torque.
(6) A fixing portion for fixing to the installation destination can be set in the connecting member 37, and the vibration actuator 10 can be fixed to the installation destination via the fixing portion. In this case, even if the vibration actuator 10 is fixed, the fixed connecting member 37 does not disturb the vibration of the stator and the piezoelectric element 17, and the vibration actuator 10 stabilizes a large torque even if it is small. Can be obtained.
(7) By installing the sponge body 41 containing lubricating oil on the connecting member 37, lubricating oil that promotes lubrication between the roller 30 and the contact surface 21 of the stator 13 is supplied to the roller 30. Since the lubricating oil is surrounded by the roller 30, the stator 13, and the connecting member 37, the lubricating oil does not fall off from the installation destination, and means for fixing the lubricating oil to the connecting member 37 becomes unnecessary.

(Second Embodiment)
Next, a vibration actuator according to the second embodiment will be described.
In the present embodiment, the connecting member is different from the connecting member of the first embodiment.
About a common structure except a connection member, description is abbreviate | omitted using the description of 1st Embodiment, and a common code | symbol is used.

FIG. 5 is a side view of the vibration actuator according to the present embodiment, and FIG. 6 is a view taken along the line BB in FIG.
The vibration actuator 60 shown in FIGS. 5 and 6 includes a connecting member 61.
As shown in FIG. 6, the connecting member 61 has a rectangular cross-sectional shape and includes a pair of connecting parts 62, a first connecting part 63, and a second connecting part 64.
A through hole 65 is formed in the pair of connecting portions 62, and the connecting portion 62 supports the rotating shaft 34 via the bearing 36.
The 1st connection part 63 is a site | part which connects a pair of connection part 62 in the stator 13 side, and is equivalent to the connection part 39 in the connection member 37 of 1st Embodiment.
A screw hole 66 for connecting the connecting rod 45 is formed at the center of the first connecting portion 63.
The second connecting portion 64 is a portion that connects the pair of connecting portions 62 on the side opposite to the stator 13 side.

The vibration actuator 60 of this embodiment has the same effects as the effects of the first embodiment.
Further, since the vibration actuator 60 of the present embodiment includes the connection member 61 having a square cross section, the rigidity of the connection member 61 is improved as compared with the first embodiment, and the structure of the vibration actuator 60 is improved. It can be made more robust.
Moreover, since the 2nd connection part 64 is formed in the connection member 61, the 2nd connection part 64 can be made into a fixing | fixed part.
In this embodiment, the site | part which can be utilized as a fixing | fixed part increases in the connection member 61, and besides the freedom degree with respect to a fixing destination becomes high, the fixing force with a fixing destination can be improved.

  The above embodiment shows an embodiment of the present invention, and the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the invention as described below. Is possible.

In the above embodiment, the roller 30 is configured as a single member. However, the roller 30 is divided into two parts, for example, so as to be two members, or two individually manufactured members are stacked. The roller 30 may be used. Further, a speed reducer may be provided between the two divided members or the two members, or an output member such as an output link for taking out the output of the vibration actuator may be provided between the members.
In the above embodiment, the rotary shaft 34 is configured to penetrate the shaft hole 33 of the roller 30. For example, a plurality of shafts are inserted from both sides of the shaft hole 33 of the roller 30 and fixed to the roller 30, respectively. It is good also as a rotating shaft comprised by a some axis | shaft. As described above, the rotating shaft is not particularly limited as long as it is configured to support the roller 30 in a rotatable manner.
○ In the above embodiment, the connection member is a substantially U-shaped connection member or a connection member having a rectangular cross section. However, the connection member is connected to the rotating shaft on both sides of the roller and is urged by the preloading means to rotate the roller. The shape is not particularly limited as long as it can be realized.
In the above embodiment, the space portion for accommodating the connecting member is formed by the groove portion that traverses in the radial direction of the stator, but it may be a groove that does not cross, that is, a rectangular bottomed hole. In addition, although the shaft portion is provided in the stator and the shaft portion and the base portion are connected, the shaft portion is not provided in the stator, but instead the shaft portion is provided in the base portion and the shaft portion of the base portion and the stator are connected. Good.
In the above embodiment, the disc spring is used as the biasing member, but the biasing member is not limited to the disc spring. The urging member may be an element that can generate an urging force that urges the rotating shaft toward the stator, and may be, for example, an elastic resin or a coil spring. Alternatively, the connecting rod may be an elastic body and the connecting rod may function as an urging member.
In the above embodiment, the rotational force of the rotating shaft is used as an output as it is, but for example, a reduction mechanism may be configured by providing gears on the rotating shaft and the connecting member. In this case, the connecting member can also be used as an element constituting the speed reduction mechanism. In addition, by providing the speed reduction mechanism, even higher torque torque can be obtained even if it is compact.
In the above embodiment, the end of the rotating shaft is set as the output end by fixing the connecting member to the fixing destination, but the present invention is not limited to this. For example, elements other than the rotation shaft and the roller may be set as the output side by fixing the rotation shaft to a fixed destination. Also in this case, the connecting member does not hinder the vibration of the stator and the piezoelectric element as in the above embodiment.
In the above embodiment, the disc spring 50 that is an urging member is provided at the end of the base portion 11. However, as shown in the modification of FIG. 7, the cylindrical portion 72 that can accommodate the disc spring 50 is provided. It is good also considering the base 71 formed in the base 71 and provided with the cylinder part 72 as a case member. In this case, the disc spring 50 is accommodated in the cylindrical portion 72. Further, even when the urging member other than the disc spring is used, it may be accommodated inside the case member. By housing the urging member inside the case member, there is no need to provide an urging member outside, and the urging member can be protected. In addition, the size of the vibration actuator can be further reduced.

DESCRIPTION OF SYMBOLS 10, 60 Vibration actuator 11 Base part 13 Stator 15 Stator main body part 17 Piezoelectric element 19 Groove part 21 Contact surface 30 Roller 31 Outer peripheral surface 34 Rotating shaft 37, 61 Connecting member 38, 62 Connecting part 39 Connecting part 41 Sponge body 45 Rod 49 Spring support Body 50 Belleville spring 63 First connection portion 64 Second connection portion P Rotation axis

Claims (6)

A stator,
A roller in contact with and supported by the stator;
A rotating shaft that rotatably supports the roller;
Vibration means connected to the stator and generating ultrasonic vibration at a contact portion between the stator and the roller to rotate the roller;
A vibration actuator comprising: a preloading means connected to the rotating shaft and pressurizing the roller against the stator by urging the rotating shaft toward the stator;
The preload means comprises a connecting member having a pair of connecting portions connected to the rotating shaft on both sides of the roller,
The stator includes a space that accommodates the connecting member. The preload means passes through the stator and the vibration means, and is connected to the connecting member;
The vibration actuator according to claim 1, further comprising: an urging member coupled to the rod and urging the rotating shaft toward the stator.   The vibration actuator according to claim 1, wherein the roller is a single roller. A case member connected to the stator is provided,
The vibration actuator according to claim 2, wherein the case member includes a space for accommodating the biasing member.   The vibration actuator according to claim 1, wherein the connecting member has a fixing portion for fixing. The connecting member includes a facing surface that faces an outer peripheral surface of the roller,
The vibration actuator according to any one of claims 1 to 5, wherein a lubricating member containing a lubricant is disposed on the facing surface.

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