JPH10263477A - Vibration-type drive device and device with vibration-type drive device as drive source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the workability and the rigidity of the teeth part of an elastic material and prevent the squeaking from being generated by rounding the shape of the bottom connected to the straight lateral wall of a groove part formed on an elastic material. SOLUTION: A teeth part 1a is provided on both sides of a groove formed by a slit S in an elastic martial 1 on a vibratory wave motor, and the lateral faces of the teeth part 1a are formed in such a manner that the lateral faces extend toward the bottom at right angles with the top face. In addition, the lateral faces connect with the round part formed at the bottom part which is the bottom of teeth. The dimensions of the round in the peripheral direction of the round part are to be set within ±20% of the full round. Thus, a moving material 6 is brought into contact under pressure with the elastic material 1 so that an output is obtained from a motor shaft which is an output axis connected to the rotating moving material 6. Consequently, it is possible to increase the rigidity of the teeth part 1a to be formed in the groove part without transforming the teeth part 1a into a trapezoidal shape as a whole, and thereby, contribute to the stabilization of drive characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration type driving device such as a vibration wave motor and a device using the vibration type driving device as a driving source, and more particularly to a shape of a tooth portion of an elastic body constituting a vibration body. .

[0002]

2. Description of the Related Art A vibration type (vibration wave) driving device has a basic configuration in which an alternating signal such as an AC voltage is applied to an electro-mechanical energy conversion element such as a piezoelectric element to form an annular shape, an oblong shape, or the like. A vibrating body in which drive vibration is excited by an elastic body such as a rod has a vibrating body, and a contact body that presses against the vibrating body and the vibrating body are relatively moved, or a sheet material such as paper is applied to the elastic body It has been proposed to perform sheet feeding by contact with pressure, for example, to use as a paper feeding device of a printer.

FIG. 6 is a sectional view showing the configuration of a vibration wave motor as a conventional vibration type driving device. In the figure, reference numeral 1 denotes a ring-shaped metal elastic body made of a flexible material such as stainless steel or phosphor bronze, and a piezoelectric element group in which two groups of piezoelectric elements polarized on one end face are formed in a ring shape. 2 are adhered concentrically. A slider material (friction material) 3 made of resin, metal, ceramic, or the like is attached to the other end surface of the elastic body 1.

[0004] Electrodes are arranged on both end faces of the piezoelectric element group 2 and subjected to a polarization treatment so as to generate a traveling wave on the surface of the slider material 3. On the surface of the elastic body 1 on the slider member 3 side, a plurality of comb-shaped grooves are regularly formed in the circumferential direction to increase motor efficiency. A vibrating body (stator) is constituted by the elastic body 1, the piezoelectric element group 2, and the slider member 3.

The piezoelectric element group 2 has a flexible surface on the side opposite to the elastic body 1 for extracting a drive signal and a signal from a sensor unit for detecting a vibration state of a motor provided on the piezoelectric element. The substrate 4 is fixed.

The inner peripheral portion 1b of the elastic body 1 is formed in a thin disk shape, and an inner peripheral fixing portion 1c following the inner peripheral portion 1b is fixed to the base member 5 by bonding or screws. .

On the other hand, on the surface of the slider member 3, a moving body 6 as a contact body is provided with an anti-vibration rubber 7 arranged on an inner peripheral step.
The elastic body 1 is coaxially pressurized and contacted by a leaf spring 8 through the shaft, and the inner diameter of the leaf spring 8 is fixed by a disc flange 9 tightly fitted to the motor shaft 10. The motor shaft 10 is supported by bearings 11 and 12 fitted to the base member 5, and retains the pressing force between the elastic body 1 and the moving body 6 by the leaf spring 8 by the retaining ring 13. The spacer 14 applies a preload to the bearing 11,
The amount of whirling of the motor shaft 10 is reduced.

FIG. 7 is a view in which a part of the vibrating body shown in FIG. 6 is developed in a circumferential direction. As shown in FIG. 7A, a plurality of elastic bodies 1 of the vibrating body are provided along the circumferential direction. And a slider member 3 is attached to the tip end surface of the tooth portion 1a between the slits S. The bottom of this tooth shape is formed in a substantially square shape.

On the other hand, 2
When an AC voltage having a frequency of the natural frequency of the elastic body 1 is applied to the piezoelectric element group 2 including the group of piezoelectric elements, FIG.
As shown in the figure, in the elastic body 1, the standing wave of each group is excited in a resonance state, and a progressive vibration wave is formed in the circumferential direction by the combination of the standing waves of both groups. A motion is performed to increase the vibration amplitude starting from the tooth bottom. Then, the moving body 6 that is in pressure contact with the vibrating body is rotationally driven by the frictional force between the sliding body of the vibrating body and the moving body 6.

FIG. 8 shows a characteristic curve of the frequency versus the rotation speed of the vibration wave motor using the vibrating body having the square roots. In general, the characteristic curve of the driving frequency versus the rotational speed of the vibration wave motor has a sharp curve at the low frequency side and a gentle curve at the high frequency side (the area to be used for drive control) with the resonance point showing a peak as a boundary. Ideally, there is no inflection point.

However, the slope of the characteristic curve of frequency versus rotation speed shown in FIG. 8 has changed from a certain frequency in the frequency range for driving. In such a case, the motor characteristics change around the frequency at the arrangement point,
Stable motor characteristics cannot be obtained. In addition, there was a case where squealing occurred.

As a cause of such a phenomenon, since the rigidity of the tooth portion 1a is low, a torsional vibration other than the circumferential direction is generated in the tooth portion 1a, and the vibration form on the inner diameter side and the outer diameter side of the elastic body 1 is generated. Therefore, the vibration amplitude changes, and it is considered that the above-mentioned change in the characteristics occurs when the contact with the moving body on the inner diameter side comes into contact with the outer diameter side.

As a countermeasure, Japanese Patent Application Laid-Open No. 63-11073 proposes to increase the rigidity of the teeth 1b by forming the teeth 1b into a trapezoidal shape as shown in FIG. Also, the publication discloses that the inclination angle of the side surface of the tooth portion from 90 degrees or less to 9 degrees from the top surface of the tooth portion to the bottom of the tooth.
It is also disclosed to vary between around 0 degrees.

[0014]

Although the rigidity of the teeth of the elastic body can be increased by taking the above-described countermeasures in the conventional example, the same frequency as that in the conventional case where the tooth bottom is square is used. In order to drive the slits, it is necessary to make the width of the teeth thinner or to make the depth of the slit considerably larger than before without changing the width of the teeth.

Further, when a friction member is stuck on the upper part of the teeth, a part without teeth is cut off after the friction material sheet is stuck. However, since the slit is not straight, it cannot be cut off.

The squeal was not so effective.

An object of the first invention according to the present application is to provide a vibration-type driving device capable of improving the processing and rigidity of the teeth of an elastic body and preventing the occurrence of squeal.

An object of a second invention according to the present application is to provide a device which does not generate squeal and uses an improved vibration type driving device as a driving source.

[0019]

According to a first configuration for realizing the object of the first invention according to the present application, an alternating signal is applied to an electro-mechanical energy conversion element so that a groove portion for expanding vibration displacement is formed. In the vibration-type driving device having a vibrating body that forms a driving vibration on the formed elastic body, the groove formed in the elastic body has an R-shaped bottom connected to a straight side wall. Things.

A second configuration for realizing the object of the first invention according to the present application is that an alternating signal is applied to an electro-mechanical energy conversion element, so that an elastic body having a groove for expanding vibration displacement is formed. In a vibration type driving device having a vibrating body that forms driving vibration and a contact body that comes into contact with the vibrating body, and the vibrating body and the contact body are relatively moved, the groove formed in the elastic body is The bottom portion connected to the straight side wall has a round shape.

A third structure for realizing the object of the first invention according to the present application is that an alternating signal is applied to an electro-mechanical energy conversion element, so that an elastic body having a groove for expanding vibration displacement is formed. A vibrating body that forms driving vibration, a moving body that contacts the vibrating body, and an output shaft that is connected to the moving body, and moves the moving body with respect to the vibrating body; In the vibration type driving device to rotate,
The groove formed in the elastic body has an R-shaped bottom portion connected to a straight side wall.

A fourth structure for realizing the object of the first invention according to the present application is an R-shaped member formed at the bottom of the groove of the elastic body.
The R dimension in the circumferential direction of the shape part is set to be within a full R ± 20%.

According to a fifth configuration for realizing the object of the first invention according to the present application, an alternating signal is applied to an electro-mechanical energy conversion element to provide an elastic body having a groove portion for expanding vibration displacement. In a vibration type driving device having a vibrating body for generating driving vibration, the groove formed in the elastic body has straight side walls, and the bottom has an R shape along a radial direction. .

A sixth structure for realizing the object of the first invention according to the present application is that an alternating signal is applied to an electro-mechanical energy conversion element so that an elastic body having a groove for enlarging vibration displacement is formed. In a vibration type driving device having a vibrating body that forms driving vibration and a contact body that comes into contact with the vibrating body, and the vibrating body and the contact body are relatively moved, the groove formed in the elastic body is , Having a straight side wall and a bottom portion having an R shape along the radial direction.

A seventh configuration for realizing the object of the first invention according to the present application is that an alternating signal is applied to an electro-mechanical energy conversion element to form an elastic body having a groove for expanding vibration displacement. A vibrating body that forms driving vibration, a moving body that contacts the vibrating body, and an output shaft that is connected to the moving body, and moves the moving body with respect to the vibrating body; In the vibration type driving device to rotate,
The groove formed in the elastic body has a straight side wall, and the bottom has an R shape along the radial direction.

According to an eighth aspect of the present invention for realizing the object of the first invention, the elastic body is formed in an annular shape.

In a ninth configuration for realizing the object of the first invention according to the present application, the elastic body is formed in an oval ring shape having a straight portion and an arc portion.

According to a tenth aspect of the present invention for realizing the object of the first invention, the elastic body is provided with a friction member on a top surface of a tooth formed between grooves.

In an eleventh configuration for realizing the object of the first invention according to the present application, the elastic body is formed of aluminum.

A configuration for realizing the object of the second invention according to the present application is such that the driven body is driven by using the above-described vibration type driving device as a driving source.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.

FIG. 1 is a developed view of a part of a vibrating body of a vibration wave motor to which the present invention is applied as viewed in a circumferential direction.

The groove portion of the elastic body in the conventional vibration wave motor has an R-shape in the present embodiment, while the shape of the tooth bottom is square. That is, the side surface of the tooth portion 1a formed on both sides of the groove formed by the slit S is formed at right angles to the top surface toward the bottom portion, and the R side portion is formed at the bottom surface which is the tooth bottom. Connected with.

FIG. 2A shows a conventional elastic body having a right-bottom shape, and FIG. 2B shows an elastic body having a bottom shape according to the present embodiment. This is a simulation showing how the teeth are displaced when given.
In the conventional elastic body shown in FIG. 2A, it can be understood that the tooth bottom has extremely large distortion and the rigidity of the tooth itself is small.
On the other hand, in the present embodiment, it can be understood that the distortion at the tooth bottom is small and the rigidity of the tooth itself is large.

Next, the relationship between the root R and the bending stiffness in the present embodiment is shown in FIGS. 2 (c) and 2 (d). FIG. 2C shows the size of the root R, and FIG. 2D shows the relationship between the size of the root R and the bending stiffness of the tooth when the size of the root R is changed. Here, since the width of the slit is 1, the full R in this specification indicates R0.5.

As shown in FIG. 2D, the flexural rigidity is R
It can be seen that the value is the highest at 0.5. In addition, in order to obtain the effect of making the tooth bottom R, approximately R 0.4 to
It can be seen that R0.6, that is, the case of full R ± 20% is good.

FIG. 3 shows the frequency vs. rotation speed curve characteristics of the motor using this embodiment.

As shown in FIG. 3, the discontinuity point of the frequency vs. rotation speed curve which has occurred in the conventional example is eliminated. At this time, the squeal generated in the conventional example is also eliminated.

Here, the cause of the disappearance of the squeal is that when the bottom of the teeth is square, the stress concentrates on that portion when the vibrator is vibrated, and unnecessary vibration which generates the squeal is generated. It is considered that the rigidity is increased by adopting the R shape of the present embodiment, stress concentration is reduced, and unnecessary vibration is eliminated.

On the other hand, as in the present embodiment, the rigidity of the tooth bottom can be increased, so that the stress concentration at the tooth bottom can be alleviated. For example, aluminum or the like can be used.

As described above, in the present embodiment, the rigidity of the teeth is increased and the stress concentration at the bottom of the teeth is alleviated.
Stable motor characteristics can be obtained.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
An embodiment will be described.

FIG. 4 is a sectional view of a part of the vibrating body of the vibration wave motor. In the first embodiment shown in FIG. 1, the R portion is formed in the circumferential direction at the bottom of the tooth portion of the elastic body, but in the present embodiment, the R portion is formed along the radial direction at the bottom of the tooth portion. In this case, an R portion is formed.

With such a configuration, it is possible to further suppress torsional vibration.

By combining this embodiment with the first embodiment, more stable motor characteristics can be obtained.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
An embodiment will be described.

FIG. 5 is a schematic view of a paper feeder using the vibration wave motor of the first or second embodiment as a drive source.

Reference numeral 21 denotes a roller for feeding paper, and a bearing 22 on which an appropriate preload is applied is disposed at an end opposite to the side where the vibration wave motor USM is coupled. On the motor shaft 10 of the motor USM, a pulse plate 2 for detecting the rotation speed and rotation angle of the motor is provided on the opposite side of the roller 21.
3. An optical detection element 24 and a detection element mounting case 25 are provided. Since the pulse plate 23 is directly attached to the motor shaft, the accuracy is good.

For coupling the vibration wave motor USM and the roller 21, the motor shaft 10 is lightly pressed into a screw hole 21a provided in the roller 21 and further fixed from the side with a set screw 26.

With such an apparatus configuration, the roller 21 can be accurately rotated.

In the above-described embodiment, the moving body 6 is brought into pressure contact with the vibrating body 1 as a vibration type driving device, and an output is taken out from a motor shaft which is an output shaft connected to the rotating moving body. However, the output may be directly taken out of the moving body without providing an output shaft, or a vibration type drive that conveys an object to be conveyed such as paper or a card to the vibrating body 1 under pressure. The vibrating body may be an elliptical shape as shown in FIG. 10, and any vibrating body may be used as long as a groove for increasing the amplitude is formed in the elastic body. FIGS. 10A and 10B show an elliptical elastic body having a linear portion and an arc portion, and FIG.
The piezoelectric element 16 is bonded to one end face of the piezoelectric element 1.
6 has two piezoelectric element groups whose positional phases are shifted by た wavelength as shown in (b), and each group is subjected to a polarization process with a phase difference of half a wavelength ( 16a1 to 16a5
16b1 to 16b5), these polarization patterns are provided in accordance with the actual displacement of the elastic body 1.

[0052]

According to the first to third aspects of the present invention, the groove for enlarging the vibration displacement of the elastic body has an R-shape at the bottom connected to the straight side wall. The rigidity can be increased without forming the tooth portion formed between them as a trapezoid as a whole, and the groove can be easily processed. Further, it is possible to stabilize and improve the driving characteristics as compared with the conventional case.

According to the first to fourth aspects of the present invention, the rigidity of the teeth formed between the grooves can be increased.

According to the fifth to seventh aspects of the present invention, even if the bottom of the groove of the elastic body having the groove for enlarging vibration displacement is rounded along the radial direction, the rigidity of the teeth between the grooves is increased. Can be increased. Further, it is possible to stabilize and improve the driving characteristics as compared with the conventional case.

According to the eighth and ninth aspects of the invention,
A groove for expanding vibration displacement is formed in the elastic body, and an elastic body of an effective form for suppressing vibration of the tooth part itself therebetween can be provided. Can be improved.

According to the tenth aspect of the present invention, for example, abrasion due to contact with a counterpart material such as a moving body or a contact body is good, and the driving characteristics can be stabilized and improved as compared with the conventional case. .

According to the eleventh aspect, aluminum can be used as the elastic body.

According to the twelfth aspect, the driven body can be stably driven by the vibration wave driving device.

[Brief description of the drawings]

FIG. 1 is a development view of a vibrating body and a moving body showing a first embodiment in which the present invention is applied to a vibration wave motor.

2A is a diagram showing a result of simulating the movement of a tooth portion of the vibrating body of FIG. 1; FIG.
(C) is a diagram showing a root R of the first embodiment, and (d) is a diagram showing a relationship between R and bending rigidity in (c).

FIG. 3 is a curve characteristic diagram of frequency versus rotation speed of the vibration wave motor using the first embodiment of the present invention.

FIG. 4 is a partial sectional view of a vibrating body showing a second embodiment in which the present invention is applied to a vibration wave motor.

FIG. 5 is a sectional view of a paper feeding device according to a third embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional vibration wave motor.

FIG. 7 is a development view of a vibrating body and a moving body of a conventional vibration wave motor, and is a cross-sectional view showing a state of an elastic body when the state changes from a stationary state to a driving state.

FIG. 8 is a diagram showing a curve characteristic of frequency versus rotation speed of a conventional vibration wave motor.

FIG. 9 is a development view of a vibrating body and a moving body of another conventional vibration wave motor.

10A and 10B show another embodiment, in which FIG.
(B) is a bottom view showing a polarization pattern of the piezoelectric element.

[Description of Signs] 1: Elastic body 2, 16: Piezoelectric element group 3: Slider material 4: Flexible board 5: Base plate 6: Moving body 7: Anti-vibration rubber 8: Leaf spring 9: Disk flange 10: Motor shaft 11 , 12: Bearing 13: Retaining ring 14: Spacer

Claims (12)

[Claims] 1. A vibration-type driving device having a vibrating body that forms a driving vibration on an elastic body having a groove for expanding vibration displacement by applying an alternating signal to an electro-mechanical energy conversion element. The vibration-type driving device, wherein the groove formed in the body has an R-shaped bottom connected to a straight side wall. 2. A vibrating body that forms a drive vibration on an elastic body having a groove for expanding vibration displacement by applying an alternating signal to an electro-mechanical energy conversion element, and a contact body that contacts the vibrating body. In the vibration-type driving device that relatively moves the vibrating body and the contact body, the groove formed in the elastic body has an R-shaped bottom connected to a straight side wall. A vibration type driving device characterized by the above-mentioned. 3. A vibrating body that forms a driving vibration on an elastic body having a groove for expanding vibration displacement by applying an alternating signal to an electro-mechanical energy conversion element, and a moving body that contacts the vibrating body. And an output shaft connected to the moving body, wherein the vibration type driving device moves the moving body with respect to the vibrating body and rotates the output shaft. The groove formed in the elastic body Is a vibratory drive device characterized in that the bottom connected to the straight side wall has a round shape. 4. An R formed at a bottom of a groove of the elastic body.
4. The vibration type driving device according to claim 1, wherein an R dimension in a circumferential direction of the shape portion is within a full R ± 20%. 5. A vibratory drive device having a vibrating body that forms a driving vibration on an elastic body having a groove portion for expanding vibration displacement by applying an alternating signal to an electro-mechanical energy conversion element, The vibration type driving device, wherein the groove formed in the body has straight side walls, and the bottom has an R shape along the radial direction. 6. A vibrating body that forms a driving vibration on an elastic body having a groove for expanding vibration displacement by applying an alternating signal to an electro-mechanical energy conversion element, and a contact body that contacts the vibrating body. In the vibration type driving device for relatively moving the vibrating body and the contact body, the groove formed in the elastic body has a straight side wall, and the bottom has an R shape along a radial direction. A vibration type driving device characterized by the following. 7. A vibrating body that forms a driving vibration on an elastic body having a groove for expanding vibration displacement by applying an alternating signal to an electro-mechanical energy conversion element, and a moving body that contacts the vibrating body. And an output shaft connected to the moving body, wherein the vibration type driving device moves the moving body with respect to the vibrating body and rotates the output shaft. The groove formed in the elastic body Is a vibratory drive device having straight side walls and a bottom portion having an R shape along a radial direction. 8. The vibration type driving device according to claim 1, wherein the elastic body is formed in an annular shape. 9. The elastic body according to claim 1, wherein the elastic body is formed in an elongated annular shape having a straight portion and an arc portion.
8. The vibration type driving device according to any one of items 7 to 7. 10. The vibration-type drive according to claim 1, wherein the elastic body is provided with a friction member on a top surface of a tooth portion formed between the grooves. apparatus. 11. The vibration type driving device according to claim 1, wherein said elastic body is formed of aluminum. 12. An apparatus using a vibration-type driving device according to claim 1 as a driving source and driving a driven body.