JPH1175379A - Driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a driving efficiency without using a control system for switching a plurality of actuators. SOLUTION: When driving voltages are applied to four actuators 30 simultaneously, vibrations with a plurality of modes are harmoniously generated in elastic elements constituting respective actuators 30 and elliptical movements are respectively produced on the output take-out parts of the actuators 30 approximately simultaneously. A plurality of driving rollers 24 which are brought into contact with the respective output take-out parts by pressures are respectively driven to rotate by the elliptical movements of the output take-out parts of the respective actuators 30. At that time, as driving forces generated by the four actuators 30 are transmitted over all the rollers 24 by a belt 60, even if a driven object 70 is not always brought into contact with all the rollers 24, the driven object 70 can be driven by the driving forces generated by all the actuators 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a driving device,
More specifically, the present invention relates to a driving device that rotates a rotating member using a vibration actuator, and drives a driven body by the rotating force of the rotating member.

[0002]

2. Description of the Related Art Conventionally, an elastic body is vibrated by an electromechanical transducer such as a piezoelectric element, and a plurality of vibration modes, for example, longitudinal vibration and bending vibration are generated in the elastic body harmoniously. 2. Description of the Related Art A vibration actuator that generates an elliptical motion in an elastic body (or an output extraction unit provided in a part thereof) is known. Such a vibration actuator has characteristics such as good controllability, high holding power, and quietness, and typical examples include a circular return type and a linear type. The yen return type vibration actuator is the camera AF
It is used for motors and the like. Further, as a linear vibration actuator, for example, Japanese Patent Application Laid-Open No. 7-14377
Japanese Unexamined Patent Publication No. 1 (Kokai) No. 1 is known, and is used, for example, in a paper feed mechanism. In a paper feed mechanism using a vibration actuator of this type, an output take-out portion of the actuator is brought into pressure contact with a driving roller, and the driving roller and the driven roller pinch a paper as a conveyed object. The paper is conveyed by rotating the driving roller by an actuator.

[0003]

In the above-described paper feed mechanism, the paper to be transported has a certain length (sufficiently longer than the length of the actuator in the length direction).
Since the transport distance is almost the same as the length of the paper, if the transported paper is sandwiched between the driven roller and the drive roller and transport is started, the transport is continued until the transport is completed. Since a state in which any part of the conveyed object is always held between the driven roller and the driven roller is maintained, the conveyed object can be smoothly conveyed by the single vibration actuator.

However, there is a case where it is desired to convey (or drive) a conveyed object having a relatively short length (for example, about twice or less the length of the actuator) over a distance of twice or more the length thereof. It is necessary to arrange a plurality of vibration actuators and a plurality of driving rollers rotated by each actuator on a straight line at predetermined intervals.

In such a case, as the drive control method of the plurality of vibration actuators, there are two methods of always driving all the vibration actuators simultaneously and sequentially driving only the vibration actuators in contact with the object to be conveyed. However, the latter method requires a position sensor for monitoring the position of the object to be transported, or a sensor for detecting the magnitude of a pressing force acting on each of the vibration actuators when the respective vibration actuators are not driven. In addition, a control system for accurately switching and driving the vibration actuator based on the output of the sensor is indispensable, and the cost is increased accordingly.

On the other hand, the former method does not cause such inconveniences, but has a disadvantage that the driving efficiency of the vibration actuator that is not in contact with the object does not contribute to the conveyance, resulting in poor driving efficiency. I have.

[0007] The present invention has been made under such circumstances, and it is an object of the present invention to provide a driving device capable of increasing driving efficiency without using a control system for switching a plurality of actuators.

[0008]

According to the first aspect of the present invention, a plurality of modes of vibration are generated harmoniously in the elastic body (32), and output is provided on a part of the elastic body (32). A plurality of vibration actuators (30) for generating elliptical motion in the sections (38A, 38B); and the output extraction sections (38A, 3A) of the plurality of vibration actuators (30).
8B), and a plurality of rotating members (24) that are respectively driven to rotate by the elliptical motions of the output take-out portions and drive the driven body (70) by the rotating force.
A power transmission member (60) for interconnecting the plurality of rotating members (24) and transmitting a driving force generated by the plurality of vibration actuators (30) between the plurality of rotating members (24); And

According to this, when a driving voltage is simultaneously applied to a plurality of vibration actuators, a plurality of modes of vibrations are generated in a harmonic manner in the elastic bodies constituting the respective vibration actuators, and the vibrations are provided in some of them. Elliptical motions occur almost simultaneously at the output take-out part. Due to the elliptical motion of each output take-out portion of each actuator, each of the plurality of rotating members that are in pressure contact with each output take-out portion is rotationally driven.

In this case, since the driving force generated by the plurality of vibration actuators is transmitted between the plurality of rotating members by the power transmitting member, even if the driven object does not always contact all the rotating members. The driven object is driven by the driving force generated by all the vibration actuators via the rotating member that is in contact with the driven object. Therefore, the driving force is greater than when driving with a single vibration actuator, and the driving efficiency can be increased without using a control system for switching a plurality of actuators.

In this case, various types of power transmission members are conceivable. For example, as in the second aspect of the present invention, the power transmission member comprises a shaft (24a) of the plurality of rotating members (24). ) May be an endless annular member (60). Here, a typical example of the endless annular member is a belt that drives a rotating member by frictional force.

According to a third aspect of the present invention, a shaft portion of each of the rotating members is provided with a tooth portion extending over the entire circumference, and a power transmission member is formed so as to mesh with the tooth portion. It may be. In this case, the driving force generated by the plurality of vibration actuators is more reliably transmitted among the plurality of rotating members due to the engagement between the teeth of the shaft portion of each rotating member and the power transmission member, and the driving efficiency is further improved. improves.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
A description will be given based on FIG.

FIG. 1 is a plan view of a driving device 10 according to one embodiment. Here, as will be described later, in the present embodiment, the driving device main body case 1 constituting the driving device 10
2 is used, the drive device body case 12
, A Y axis in a direction orthogonal to the X axis in the plane of FIG. 1, and a Z axis in a direction orthogonal to the plane of FIG. 1 orthogonal to the X axis and the Y axis. In the following description, the directions indicated by the arrows indicating the X and Y axes in FIG. 1 are indicated by + X and + Y directions, and the opposite direction is indicated by −, as necessary.
It shall be used separately from the X and -Y directions.

The driving device 10 has a bottomed rectangular frame-shaped driving device main body case 12 having an open upper surface (a front surface in FIG. 1), and a -Y direction side inside the driving device main body case 12. A plurality (four in this case) of drive units 1 arranged at predetermined intervals along the X-axis direction near the side wall
4 ₁ , 14 ₂ , 14 ₃ , 14 _4, and a plurality (eight in this case) of driven rollers 1 arranged at predetermined intervals along the X direction near the + Y direction side wall inside the drive device main body case 12.
6 _1, 16 _2, ..., and a 16 _8.

The drive units 14 ₁ , 14 ₂ , 14 ₃ , 1
Of the ₄ , the drive unit 1 located at the end in the −X direction
4 between the ₁ and the -X direction side wall of the drive unit main body case 12, and a rectangular parallelepiped shape regulating member 18A for restricting the movement of the drive unit 14 ₁ in the -X direction is provided, likewise +
Between the + X direction side wall of the drive unit 14 ₄ and the driving device main body case 12 located at the end of the X-direction, the regulating member 18B for restricting the movement of the drive unit 14 ₄ + X direction
Is provided. Between the drive unit 14 ₁ and the drive unit 14 _2, the regulating member 20A for regulating the drive unit 14 ₁ in the + X direction of movement and the drive unit 14 ₂ of the movement in the -X direction at the same time are arranged. Similarly, between the drive unit 14 ₂ and the drive unit 14 _3, the regulating member 20B for regulating the drive unit 14 ₂ of the + X direction of movement and the drive unit 14 ₃ of the movement in the -X direction at the same time it is arranged . Similarly, between the drive unit 14 ₃ and the drive unit 14 _4, movement of the drive unit 14 ₃ + X direction and the driving unit 14 ₄ -X
A regulating member 20C for simultaneously regulating the movement in the direction is arranged. Therefore, the drive units 14 ₁ , 14 ₂ , 1
4 _3, 14 ₄ are all moving in the X-axis direction is restricted.

FIG. 2 (a), the (b), 1 single drive unit 14 ₂ constituting the driving device 10 is shown removed. 2 (a) is a front view, partly in cross section, a drive unit 14 _2, B-B in FIG. 2 (b) FIGS. 2 (a)
FIG.

The drive unit 14 _2, the unit case 22 of box-shaped, the walls 22a on both sides in the Z-axis direction of the unit case 22 (front side and back side in FIG. 2 (a)),
A drive roller 24 as a pair of rotating members supported by the shaft 22 b is provided, and a vibration actuator 30 housed in the unit case 22 and rotationally driving the pair of drive rollers 24.

One surface of the unit case 22 (FIG. 2)
An opening having a predetermined shape is formed in the bottom surface in (a), and the distal ends of the pair of drive rollers 24 are exposed from the opening (see FIG. 2A). In the present embodiment, notches (not shown) of a predetermined shape for passing a belt 60 described later are formed on the side walls of the unit case 22 in the + X direction and the −X direction.

As shown in the exploded perspective view of FIG. 3, the driving roller 24 has a small diameter portion 24a as a shaft portion at the center in the longitudinal direction (Z axis direction), and both ends of the driving roller 24 have a large diameter portion. And a support shaft 25 protrudes from the center of both end surfaces in the longitudinal direction. Then, each support shaft 25 is fitted into a circular hole formed on each of the walls 22a and 22b on both sides in the Z-axis direction of the unit case 22, so that the drive roller 24 is rotatably supported by the unit case 22. (Figure 1,
(See FIG. 2).

In the present embodiment, as the vibration actuator 30, an ultrasonic actuator utilizing an ultrasonic vibration region is used. This vibration actuator 3
0, as shown in FIG. 3, a rectangular plate-like elastic body 32 having a predetermined thickness and a longitudinal direction (X
(Axial direction) A pair of piezoelectric members 34A and 34B, which are electromechanical transducers, fixed at a predetermined distance in the vicinity of the center, and a pair of output extraction portions 38A and 38B protruding from the other surface of the elastic member 32. And the pair of output extraction units 38A,
A pressure mechanism 40 (see FIG. 2A) for bringing the 38B into pressure contact with the pair of drive rollers 24 is provided. Here, the elastic body 32 and the output take-out portions 38A and 38B may be integrally formed of the same material, or may be formed of the same or different materials as separate bodies.

The piezoelectric bodies 34A and 34B are subjected to multiple modes of vibration, specifically, a longitudinal vibration mode (here, L1 Mode) and the bending vibration mode (B4 mode in this case) are generated harmoniously, and the driving force is generated in the output extraction units 38A and 38B by an elliptical motion which is a combination of these two vibration modes.

The output take-out portions 38A and 38B are provided at positions of antinodes (portions where the amplitude is maximum) of the bending vibration generated during driving.

Although not shown, the elastic body 3
4 is generally connected to a GND (ground) potential. In this case, the electrode (common electrode) may be formed by, for example, soldering a lead wire to the elastic body 32 or bonding a metal foil with the lead wire to the elastic body 32.

At both ends of the center of the elastic body 32 in the longitudinal direction,
Notches 32a and 32b having a semicircular cross section communicating with the thickness direction (Y-axis direction) are formed. Here, the cross-sectional shape of these notches 32a and 32b is not limited to a semicircular shape, but may be any shape as long as it can engage with engaging portions 44A and 44B provided on a support member 42 described later. Other cross-sectional shapes such as a rectangle and a triangle may be used.

The pressing mechanism 40 is shown in FIGS.
As shown in FIG. 3, rectangular plate-shaped support members 42, and notches 32a and 3b formed in the elastic body 32 are provided at both ends in the Z-axis direction of one (+ Y direction) surface of the support members 42.
It is composed of a pair of engaging portions 44A and 44B made of rod-shaped members having a circular cross section arranged at equal intervals to the interval of 2b, and a pair of compression coil springs respectively mounted on the outer peripheral portions of these engaging portions 44A and 44B. And a pressure spring 46.

As shown in FIGS. 2A and 2B, the engaging portions 44A and 44B of the support member 42 are engaged with the notches 32a and 32b of the elastic body 32 from the -Y side. The movement of the elastic body 32 in the Z-axis direction is restricted. Further, in the state shown in FIG. 2A, the pair of pressure springs 46
4A and 34B, the pressing spring 46
Presses the elastic body 32 in the + Y direction via the piezoelectric bodies 34A and 34B. Thus, the output take-out portions 38A and 38B provided on the elastic body 32 are in pressure contact with the pair of drive rollers 24, respectively. As described above, when the pressure spring 46 is assembled in the unit case 22, one end surface of the pressure spring 46 comes into contact with the piezoelectric body (electrode portion thereof).

In the present embodiment, the pressing position by the pressing mechanism 40 is the central portion in the longitudinal direction of the elastic body 32, and this position is a position that becomes a common node of the longitudinal vibration and the bending vibration generated in the elastic body 32. is there. Therefore, the suppression of vibration due to pressurization is minimized, and pressurization can be performed without impairing the driving force.

[0029] As described above, the drive unit 14 ₂ is formed. Other drive units 14 ₁ , 14 ₃ , 1
4 ₄ is configured similarly as the driving unit 14 _2.

Returning to FIG. 1, the drive units 14 ₁ , 1
4 _2, 14 _3, 14 ₄ and the driving device main body case 12 -Y
The two compression coil springs 50 are arranged between the side walls in the direction, and the drive units 14 ₁ , 14 ₂ , 14 ₃ ,
14 ₄ is constantly urged in the + Y direction by these compression coil spring 50. In addition, the drive device body case 12
At the bottom of these drive units 14 ₁ , 14 ₂ , 1
4 _3, 14 ₄ stopper (not shown) for regulating so as not to move is provided on the + Y side than necessary.

The eight driven rollers 16 ₁ , 16 ₂ ,...
..., 16 _8, the drive unit 14 _1, 14 _2, 14 _3,
It is arranged at substantially opposite positions respectively to the drive roller 24, which is the two provided 14 _4. These eight driven roller 16 _1, 16 _2, ..., 16 _8, a bottom wall of the drive unit main body case 12, provided along the X-axis direction in the + Y direction end portion upper face of the drive unit main body case 12 Both ends in the Z-axis direction are supported by the plate-shaped holding member 52 so as to be freely rotatable.

Then, these eight driven rollers 16 ₁ ,
16 _2, ..., the driven member 70 is sandwiched with a moderate force by three of the 16 ₈ (the driven roller 16 ₁ in FIG. 1, 16 _2, 16 ₃₎ and three drive rollers 24 corresponding to those Supported. Here, the length of the driven body 70 is
No matter where the position is, the length is such that it is always supported while being sandwiched between the plurality of driven rollers 16 and the driving roller 24.

Further, in this embodiment, as shown in FIG. 1, four drive units 14 ₁ , 14 ₂ , 14 ₃ ,
14 ₄ on the belt 60 as an endless annular member to the small diameter portion 24a of the two total of eight provided drive rollers 24 (and the power transmission member) is wound (is wound) and, thereby eight drive The rollers 24 are connected to each other. In addition, a pin 62 that is in pressure contact with the outer surface of the belt 60 is provided at a substantially central position between the adjacent drive units 14.
_1, 62 _2, 63 ₃ are disposed respectively. These pins 62 ₁ , 62 ₂ , and 63 ₃ are connected to the drive device body case 1.
2 is provided in an upright state. These three
A predetermined tension is applied to the belt 60 by the pins,
All of the eight drive rollers 24 are hardly idle.

According to the driving device 10 configured as described above, the driving units 14 ₁ , 14 ₂ , 14 ₃ , 14 ₄
The piezoelectric body 34A of each vibration actuator 30 constituting
By applying an AC voltage (sine wave, cosine wave) of a predetermined frequency having a phase that is electrically different by 90 degrees to 34B, vibrations of the L1 mode and the B4 mode are generated in each elastic body 32 in harmony. As a result, a driving force is generated in the output extraction portions 38A and 38B of each vibration actuator 30 by an elliptical motion which is a combination of two vibration modes, and the eight driving rollers 24 rotate in a predetermined direction. At this time, since the eight driving rollers 24 are connected to each other by the belt 60, the driving force generated by the four vibration actuators 30 by the belt 60 is reduced by the eight driving rollers 24.
It is transmitted between each other. As a result, the three drive rollers 24
Even though only the driven body 70 is in pressure contact with the driven body 70, the driven body 70 is driven by the total driving force generated by the four vibration actuators 30 (FIG. 1).
Double arrow A). In this case, all of the eight drive rollers 24 rotate at the same speed.

As described above, according to the driving device 10 of the present embodiment, the driving force generated by the four vibration actuators 30 is transmitted by the belt 60 to the eight driving rollers 24.
Transmitted from each other, the four actuators 3
In spite of always driving 0 simultaneously, any driving force can be effectively used, and waste is eliminated. Therefore, the driving efficiency can be increased without using a control system or the like for switching the vibration actuator. Here, the driving device 10 of the present embodiment is suitable for, for example, a filter switching device using an optical filter as the driven body 70, in which case, the bottom wall of the case 12 is formed of a transparent member. It is necessary to make a hole of an appropriate shape.

In the above embodiment, the case where the belt is used as the power transmission member has been described, but the present invention is not limited to this. For example, instead of the belt 60, a belt 60 ′ having an internal gear-shaped cross section as shown in FIG. 4 is used as a power transmission member, and the entire circumference of the small diameter portion 24 a of the drive roller 24 is accordingly The teeth 27 so as to mesh with the internal teeth of the belt 60 '.
May be formed. By doing so, the driving roller 24
Can be reliably prevented from slipping between the small diameter portion 24a and the belt 60 ', and the driving efficiency can be further improved. Alternatively, a chain may be used as a power transmission member instead of the belt. In this case, the small diameter portion 24a of each drive roller 24 may be formed in a sprocket pulley shape that meshes with the chain.

In the above embodiment, the case where the ultrasonic actuator using the ultrasonic vibration region is used as the vibration actuator has been described. However, the present invention is not limited to this. Needless to say, a vibration actuator described above may be used.

Further, in the above embodiment, the case where the vibration actuator utilizing the composite vibration of the L1-B4 type is used has been described. However, not limited to this, L1-B2,
A vibration actuator using a combination of a plurality of other vibration modes, as well as a vibration actuator using another deformed contraction / longitudinal-bending mode such as L1-B8, can be used in the same manner.

In the above-described embodiment, the case where a piezoelectric body is used as the electromechanical transducer is described. However, the present invention is not limited to this, and an electrostrictive body or a magnetostrictive body can be used.

Further, in the above-described embodiment, the case where the output take-out portions 38A and 38B of the elastic body 32 are protruded from the elastic body 32 (projections) has been described. No need to provide. That is, even with the flat elastic body itself, the antinode part (the part having the maximum amplitude) of the bending vibration generated at the time of driving functions as an output extracting part. In this case,
It is sufficient that the antinode position of the bending vibration is in pressure contact with the rotating member 24.

[0041]

As described above, according to the first and second aspects of the present invention, the driving efficiency can be increased without using a control system for switching a plurality of actuators. There is no excellent effect.

According to the third aspect of the invention, the driving efficiency is further improved as compared with the first and second aspects of the invention.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing an entire configuration of a driving device according to an embodiment.

2 (a) is an enlarged view, partly in cross section, a drive unit 14 ₂ of FIG. 1 is a view taken along line B-B view of (b) is (a).

FIG. 3 is an exploded perspective view showing a vibration actuator and a driving roller that constitute the driving unit of FIG. 2;

FIG. 4 is a view for explaining another embodiment of the power transmission member.

[Description of Signs] 10 Drive device 24 Drive roller (rotating member) 24a Small diameter portion (shaft portion) 27 Tooth portion 30 Vibration actuator 32 Elastic body 38A, 38B Output take-out portion 60 Belt (power transmission member, endless annular member) 60 ′ Belt (power transmission member, endless annular member) 70 Driven body

Claims (3)

[Claims] 1. A plurality of vibration actuators for generating a plurality of modes of vibration in an elastic body in harmony and generating an elliptical motion in an output extraction part provided in a part of the elastic body;
A plurality of rotating members that respectively press and contact the output extraction portions of the plurality of vibration actuators, are each rotationally driven by the elliptical motion of each of the output extraction portions, and drive a driven body by the rotational force; And a power transmission member that connects the rotating members to each other and transmits a driving force generated by the plurality of vibration actuators to the plurality of rotating members. 2. The drive device according to claim 1, wherein the power transmission member is an endless annular member wound around shafts of the plurality of rotating members. 3. The rotary member according to claim 2, wherein a shaft portion of each of the rotary members is provided with a tooth portion extending over the entire circumference, and the power transmission member is shaped to mesh with the tooth portion. Drive.