JP2014057447A - Vibration type drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration type drive device capable of exhibiting stable motor performance from an initial point of time after assembly and improving durability.SOLUTION: A vibration type drive device includes: a vibrating body having an electromechanical energy conversion element; and a driven body having a plurality of contract bodies including a first contact body and a second contact body which come into contact with at least the vibrating body. By application of an alternating signal to the electromechanical energy conversion element, vibrational waves excited by the vibrating body cause friction drive of the driven body, and the driven body is relatively moved to the vibrating body. The distance between the first contact body and the vibrating body opposed to the first contact body is set to be smaller than that between the second contact body and the vibrating body opposite to the second contact body.

Description

  The present invention relates to a vibration type driving device (vibration wave motor) that generates vibration in a vibrating body and applies a driving force using the vibration energy.

In general, a vibration-type driving device (ultrasonic motor) includes a vibrating body in which driving vibration is formed and a driven body that is in pressure contact with the vibrating body, and the vibrating body and the driven body are driven to vibrate. It is comprised so that it may move relatively.
An example of a so-called annular vibration type driving device will be described with reference to FIG.
FIG. 8A is a cross-sectional view showing the overall configuration of the annular motor.
In the same figure, the vibrating body 100 is composed of 101, 102, and 103 components, 101 is a ring-shaped elastic body, 102 is a piezoelectric element fixed to one surface of the elastic body 101, and 103 is the elastic body. A friction member provided on the other surface.
The driven body 110 includes a cylindrical contact body 113 and a mass portion 107, and the driven body 110 is pressed against the friction member 103 by a pressurizing spring 109. Pressurized contact.
Further, the frictional force generated on the friction surface becomes a driving force to drive the driven body 110, and the rotational torque of the driven body 110 is transmitted to the shaft 111 via the pressure spring 109 and the disk 112.
FIG. 8B is a perspective view of the vibrating body 100 viewed from the driven body 110 side.
In the figure, the vibrating body 100 has a plurality of protrusions 101a arranged in a comb-tooth shape on the surface facing the driven body 110.
The piezoelectric element 102 is provided with an electrode pattern (not shown) and a power feeding means. By applying an alternating signal to the electrode pattern, bending vibration is generated in the vibrating body 100, and a high frequency is applied to the frictional contact surface on the vibrating body side. The driven body 110 is driven by forming a microfeeding motion.

Conventionally, in such a vibration type driving device, a ring type vibration type driving device has been proposed in which local wear of a contact member (contact body) is reduced and performance deterioration due to long-term driving is suppressed. .
FIG. 9 shows a structure of a driven body in the vibration type driving device disclosed in Patent Document 1.
FIG. 9A is a cross-sectional view illustrating the detailed structure of the driven body 3.
In the figure, the driven body 3 is a ring-shaped main body formed of a support body 3b, a contact body 3c extending from the end of the support section 3b to the outer diameter side, and an elastic member. 3a.
According to this configuration, the support portion 3b and the contact portion 3c can be elastically deformed in the direction of the rotation axis of the driven body, thereby preventing local contact pressure concentration of the contact member and resulting increase in wear. ing.
With this structure, it is possible to maintain smooth contact between the vibrating body and the driven body from the initial driving stage after assembly to after long-term driving. In addition, high durability is achieved by avoiding concentration of surface pressure.
FIG. 9B is a cross-sectional view showing a configuration for further enhancing the durability.
According to the figure, by arranging a plurality of driven bodies 3 concentrically, the area of the friction contact surface can be increased and the contact surface pressure can be reduced. Thereby, the durability is improved.

JP 2010-263769

However, the conventional example of Patent Document 1 has the following problems.
In the configuration shown in FIG. 9B, the plurality of contact bodies of the driven body 3 are initial contact portions that are in contact with the vibrating body 100 at the initial stage after assembly. And it is the structure which the driving force in each friction contact surface contributes to motor performance.
The initial contact portions of the plurality of contact bodies 3 and the vibrating body 100 at each position are not yet familiar with the friction contact surfaces in the initial driving stage, and are likely to be in an unstable contact state.
At this time, if a geometric error between a plurality of contact bodies such as the parallelism of the friction contact surfaces is large, the contact state of any of the contact bodies becomes unstable.
And when the contact state of one contact body becomes unstable, vibration unnecessary for motor drive will generate | occur | produce and this unnecessary vibration will propagate also to another contact body.

As described above, since the contact state is adversely affected and the contact state is deteriorated, the driving state is further unstable.
As a result, the motor performance in the initial driving stage is degraded.
Further, when the motor is driven at a high output condition at this stage, the contact surface may be damaged, and the durability thereafter may be deteriorated.
In particular, if the finishing accuracy of the frictional contact surfaces of the respective contact bodies is poor, the motor just after assembly may not be able to obtain sufficient performance.
For this reason, it is necessary to wear gently until the frictional contact surfaces of all the contact bodies which are the initial contact portions and the vibration bodies at the respective positions are well adapted by performing long-term aging drive.

  In view of the above problems, an object of the present invention is to provide a vibration type driving device that can exhibit stable motor performance from the initial stage after assembly and can improve durability. Is.

The vibration type driving device according to one aspect of the present invention is:
A vibrator having an electromechanical energy conversion element;
A driven body having a plurality of contact bodies including at least a first contact body and a second contact body in contact with the vibrating body;
By applying an alternating signal to the electro-mechanical energy conversion element, the driven body is frictionally driven by vibration excited by the vibrating body, and the driven body is moved relative to the vibrating body. A device,
The distance between the first contact body and the vibrating body facing the first contact body is the distance between the second contact body and the vibrating body facing the second contact body. The present invention relates to a vibration type driving device that is smaller than the distance.
In addition, the vibration type driving device according to one aspect of the present invention includes:
A vibrator having an electromechanical energy conversion element;
A driven body formed with a contact body in contact with the vibrating body;
By applying an alternating signal to the electro-mechanical energy conversion element, the driven body is frictionally driven by vibration excited by the vibrating body, and the driven body is moved relative to the vibrating body. A device,
The contact body formed on the driven body has a plurality of contact bodies including at least a first contact body and a second contact body,
As the friction drive proceeds from the initial stage of the friction drive, the plurality of contact bodies can start contact with the vibrating body sequentially or stepwise from the first contact body to the second contact body. The present invention relates to a vibration type driving apparatus configured as described above.

  According to the present invention, it is possible to realize a vibration type driving device that can exhibit stable motor performance from an initial time after assembly and can improve durability.

It is sectional drawing explaining the structure of a contact part vicinity. It is sectional drawing explaining the modification of the structure of a contact part vicinity. It is sectional drawing explaining the structure of a contact part vicinity. This explains the transition of the contact state and the accompanying change in motor characteristics. The control apparatus provided with the function which detects the change of a contact state with a drive frequency is shown. The procedure for detecting the change of a contact state and estimating the remaining driveable time is shown. The control apparatus provided with the function which detects the change of a contact state with a speed deviation, a drive voltage signal, and a vibration detection signal is shown. 1 shows a configuration of an annular vibration type driving device that is an example of a vibration type driving device. It is sectional drawing explaining the to-be-driven body structure in the vibration type drive device of a prior art example.

Embodiments of the present invention will be described.
The vibration type driving device of the present embodiment wears gently until the frictional contact surfaces of all the contact bodies that are the initial contact portions and the vibration bodies at the respective positions become familiar by performing aging drive for a long time. Therefore, it is configured as follows.
That is, the initial contact portion that is in contact at the initial time after assembly is gradually changed to a smooth contact state, and thereafter, a new contact body can be started to contact little by little at a time interval. .
This makes it possible to exhibit stable motor performance from the initial stage. Further, it has a plurality of contact portions, and is configured to be able to be continuously used as a motor while the contact portions are worn sequentially or stepwise.
Therefore, it is possible to provide a motor that is more suitable for high durability applications than a single contact portion.
Further, in the present motor structure, when the spatial position of the frictional contact surface changes, the motor input signal changes, so that it is possible to detect the transition of the contact state on the motor drive circuit.
This makes it possible to grasp how much durability can be expected in the entire motor life.

Examples of the present invention will be described below.
[Example 1]
As a first embodiment, a configuration example of a vibration type driving device to which the present invention is applied will be described with reference to FIG.
The vibration type driving apparatus according to the present embodiment includes a vibrating body having an electro-mechanical energy conversion element and a driven body on which a contact body that contacts the vibrating body is formed.
Then, by applying an alternating signal to the electromechanical energy conversion element, the driven body is frictionally driven by the vibration excited by the vibrating body, and the driven body is moved relative to the vibrating body. It is configured.
The specific configuration will be described by taking a general ring type vibration type driving device (rotational type vibration driving device) as shown in FIG. 9 as an example.
FIG. 1 is a cross-sectional view illustrating the configuration in the vicinity of a contact portion in Embodiment 1 of the present invention.
FIG. 1 is a cross-sectional view cut along a plane including the central axis, in which the left direction is the ring-shaped inner diameter side and the right direction is the outer diameter side.
Reference numeral 100 denotes a vibrating body, and 110 denotes a driven body. Here, the vibrating body and the driven body are in contact with each other by the motor pressure acting in the direction of the arrow in the figure.
The driven body includes a ring-shaped main body 115 made of an elastic material and three contact bodies 113 (a), 113 (b), 113 (c), and a contact body 113 (a ) Are first contact bodies, and the spare contact bodies arranged in order toward the outer periphery are called second and third contact bodies.
The second and third contact bodies are fixed to the main body 115 including the contact body 113 (a).

Each contact body has a friction contact surface 114, and is arranged so that the friction contact surface protrudes from the vibration body side in order from the first contact body.
At this time, the vibrating body 100 and the driven body 110 are in contact only with the first contact body 113 (a), and the contact surfaces of the other contact bodies are close to each other in a state substantially parallel to the contact surface on the vibration body side, and It is held with a minute clearance.
By the way, in the combination of the friction materials constituting the friction contact portion of the vibration type driving device, the wear amount of the friction contact surface 114 of the friction material having the lower hardness is generally larger than the wear amount of the other. is there.
In the present embodiment, the friction material on the driven body 110 side is made of a material having a lower hardness, and the combination is aimed to increase the amount of wear by driving on the driven body side.

The vibration type driving device (motor) of the present embodiment is in frictional contact only with the first contact body 113 (a) at the start of driving, and undertakes all the motor pressure with one contact surface.
At this time, the frictional contact surface 114 (a) of the contact body 113 (a) constitutes an initial contact portion that contacts from the initial contact state.
At this time, in the initial contact state, since contact is made only with a single contact body, wear gradually progresses with driving, and it is possible to gradually shift to a familiar contact state.
This is optimized so that the radial contact width of a single contact body is sufficiently small and the initial contact state can be shifted to a smooth contact state without any problem while maintaining a stable contact state. Because. During this time, the second and third contact bodies remain in non-contact with the vibrating body.

Next, the total amount of wear in the depth direction of the friction contact surface 114 (a) of the first contact body 113 (a) and the friction contact surface on the vibrating body 100 side is the vibration amount of the second contact body 113 (b). When the clearance amount with the body 100 matches, the contact of the second contact body starts.
At this time, the frictional contact surface 114 (b) of the second contact body does not start contact with a strong pressure from the beginning. In other words, the contact starts little by little as the wear of the first contact body progresses, and it shifts to a smooth and familiar contact at a very slow speed.
Therefore, the contact instability phenomenon that occurs when a plurality of contact surfaces start contact at once does not occur.
As a result of the transition to the stable contact of the second contact body, the driven body 110 is driven by the two friction contact surfaces 114 (a) and 114 (b) of the first and second contact bodies. The
At this time, since the motor pressure is distributed over a larger area than the initial contact portion, the contact surface pressure is reduced. Therefore, far superior durability can be realized as compared with the stage where driving is performed with a single contact surface.
Further, the third contact body 113 (c) is also brought into contact with the frictional contact surface 114 (c) in the same manner as the second contact body, and a transition to a stable contact without any problem is performed.
And the contact surface pressure is further reduced, and higher durability can be achieved. In the present embodiment, the case where the number of contact bodies is three has been described as an example, but the same effect can be obtained even when the number of contact bodies is larger than this.

A modification of the present embodiment will be described with reference to FIG.
The driven body 110 has three contact bodies. Each contact body is fixed to the main body 115, and each friction contact surface is arranged on the same plane.
On the other hand, the frictional contact surface on the vibration body 100 side has a step in the motor axial direction, and only the first contact body 113 (a) arranged on the innermost side is the initial contact portion.
And the 2nd and 3rd contact body which is a spare contact body is arrange | positioned on the outer peripheral side, and these friction contact surfaces are non-contact in an initial stage. Each contact body has a friction contact surface 114 that contacts the vibrating body 100.

FIG. 2 shows a significant step for easy understanding of the configuration, but the size of the step is arbitrary.
However, the second contact body 113 (b) can start contact before at least the friction contact surface 114 (a) at the tip of the first contact body 113 (a) disappears and the contact area is greatly reduced. It is preferable to set the step size.
In such a dimensional relationship, from the initial drive by the first contact body 113 (a), the drive by the first and second two contact bodies, and further by the first to third three contact bodies. The transition of the contact state proceeds to drive.
When the wear further proceeds in the driving state by the three contact bodies, the friction contact surface 114 (a) of the first contact body 113 (a) disappears, and the driving by the second and third contact bodies is performed. And migrate.
Finally, the friction contact surface 114 (b) of the second contact body 113 (b) disappears and only the third contact body 113 (c) is driven.

Also in the transition of the above contact state, the same effect as that of the configuration example of the present embodiment before this modification can be obtained.
That is, the initial contact portion forms a stable contact state, and the state shifts to a state in which the driven body 110 is driven by a plurality of contact bodies while maintaining the state.
On the contrary, the driving state is shifted to the driving state of only the third contact body 113 (c) while maintaining the stable driving state.
Therefore, it is possible to maintain a smooth contact state in all lifetimes.

In addition, the configuration of this modified example has a manufacturing advantage.
Specifically, in the configuration of FIG. 1, it is difficult to finish the friction contact surface after the contact bodies are individually joined to the driven body main body 115.
Therefore, the parallelism and positions of the plurality of friction contact surfaces of the contact bodies after joining are likely to vary.
However, in this modification shown in FIG. 2, it is possible to finish three friction contact surfaces simultaneously after all the contact bodies are joined to the main body.
Therefore, it is possible to easily supply a driven body in which the parallelism of each contact surface and the position of the friction contact surface when viewed in the axial direction are aligned.
As for the step on the contact surface on the side of the vibrating body, lathe machining can be performed in one pass, and when the step is formed by press molding or the like, it is even easier.
As described above, in this motor structure, since the spatial position of the contact portion changes with the lapse of the driving time, the transition of the contact state can be detected by the control device using this.

FIG. 4 illustrates the transition of the contact state and the accompanying change in motor characteristics.
FIG. 4A shows a simplified state of the transition of the contact state with the lapse of the driving time. Since the driven body according to the present embodiment includes three contact bodies, the first to fifth contact states can be achieved in all lifetimes.
First, the first to third contact states are processes in which the contact area increases. That is, the first contact state is driven by only the first contact body, the second contact state is driven by the first and second contact bodies, and the third contact state is driven by the first to third contact bodies. It is.
The fourth and fifth contact states are processes in which the contact body disappears and the contact area decreases.
That is, the fourth contact state is driven by the second and third contact bodies (the first contact body disappears), and the fifth contact state is driven only by the third contact body (first and second contact bodies). Body disappeared).

FIG. 4B shows a change in motor characteristics accompanying the transition of the contact state.
The horizontal axis is the drive frequency, and the vertical axis is the speed. For example, when shifting from the first to the fifth contact state, the drive frequency-speed characteristic curve of the motor shifts to the right.
This is because the resonance frequency of the motor changes due to changes in the spatial position and contact area of the contact portion.
When speed control is performed at a constant target speed on the premise of such characteristics, the drive frequency changes from f1 to f5 on the higher side as shown in FIG. 4B.
The change in the driving frequency due to the transition of the contact state is not limited to the one shown in this embodiment because the change direction and the magnitude relationship can be freely changed by designing the rigidity and shape of the contact body.
Here, when the lifetime of this motor is set to 5000 hours, the change in the drive frequency in each contact state is shown in FIG.
The horizontal axis represents drive time, and the vertical axis represents drive frequency when controlled at a constant speed. For the sake of explanation, the driving time in each contact state is 1000 hours.
Thus, if the drive frequency changes with the transition of the contact state, the remaining driveable time can be estimated by sequentially detecting the change in the control device.

A control device having a function of detecting a change in contact state based on a drive frequency will be described with reference to FIG.
First, an outline of the control device will be described.
A command speed is given from the controller 601, the speed signal obtained by the speed detector 609 such as an encoder and the command speed value are input to the speed deviation detector 602, and a speed deviation signal is output.
The speed deviation signal is input to the PID compensator 603, and a control signal is output.
Here, the PID compensator 603 is obtained by adding the outputs of compensators having proportional (P), integral (I), and differential (D) functions, and compensates for the phase delay and gain of the controlled object. It is generally used to construct a stable and highly accurate control system.
The control signal output from the PID compensator 603 is input to the control amount conversion unit 604, and is converted into control amounts of drive frequency, pulse width, and phase difference, which are control signals. The converted control signal is input to the pulse generator 605.
The pulse generator 605 generates a pulse signal whose drive frequency changes according to the input control signal, and a digital frequency divider, a VCO (voltage controlled oscillator), or the like is used.
Further, a pulse signal whose pulse width changes according to the control signal may be generated by PWM (pulse width modulation) control.
The drive frequency pulse signal output from the pulse generator 605 is input to the drive circuit 606, and a two-phase alternating voltage having a phase difference of 90 ° is output.
The alternating voltage is a two-phase alternating signal whose phase is shifted by 90 °. For the drive circuit 606, for example, a transformer type booster circuit or an LC booster circuit having a switching function is used.
The alternating voltage output from the drive circuit 606 is input to the electromechanical energy conversion element of the vibration type driving device 607, and the driven body of the vibration type driving device 607 is driven at a constant speed.
Similarly, the driven body 608 connected to the vibration type driving device 607 is also driven at a constant speed, the rotational speed is detected by the speed detector 609, and feedback control is performed so that the rotational speed always approaches the command speed value.

Next, means for detecting a change in the contact state will be described.
The drive frequency information output from the control amount conversion unit 604 is input to the drive frequency detection unit 610. Since the input drive frequency information fluctuates slightly due to load fluctuations during driving, the averaging process is performed at a constant period.
The averaged drive frequency information is sequentially compared with the drive frequency information read from the memory 611 by the comparator 612.
The memory 611 stores drive frequency information when the controller 601 determines that the contact state has shifted.
Based on the comparison result, the controller 601 detects a change in the contact state.

In more detail, a means for detecting a change in the contact state will be described.
FIG. 6 shows a procedure for the controller 601 to detect the first to fifth contact states and estimate the remaining driveable time.
FIG. 6A shows a step of detecting a contact state. When a drive start command is input to the controller 601, the motor is driven at a constant speed.
If it is the drive of an initial state, it will be in a 1st contact state. When a predetermined time has elapsed, the drive frequency averaged by the drive frequency detector 610 is detected (step 1).
This is compared with the drive frequency read from the memory 611, and a difference value is calculated by the comparator 612 (step 2).
If the said difference value is the same contact state, it will not change a lot.
In the initial state, a reference value or an initial value immediately after the start of driving may be stored in the memory 611 in advance.
If the difference value is larger than the threshold value, the controller 601 determines that the contact state has shifted to the next state (step 3).
As described with reference to FIG. 4C, the threshold is determined based on the amount of change in the driving frequency in each contact state.
For example, when shifting to the second contact state, a value obtained by multiplying the difference value (f2-f1) of the drive frequency by a coefficient is set.
Here, the coefficient is less than 1. Thus, when it is determined that the contact state has shifted, the latest drive frequency is updated in the memory 611 (step 4).

When this is finished, the step of estimating the remaining drivable time shown in FIG. 6B is started.
First, the controller 601 identifies which stage the contact state is in (step 5).
This is stored in the controller 601 as to which stage the contact state is in sequence, and the current contact state can always be grasped by counting up when determining the transition of the contact state in Step 3.
Then, the remaining driveable time is estimated based on the contact state (step 6). For example, if the state has shifted to the second contact state, it can be estimated that the remaining life is 4000 hours as shown in FIG.
Further, if the optimum control parameter is different in each contact state, the control gain, the drive start frequency, the pulse width, the phase difference, etc. can be changed (step 7).
Next, when the fifth contact state is entered through the first to fourth contact states, the command speed from the controller 601 may be changed (step 8).
This means that the transition to the fifth contact state means that the life of the motor is low and functions as a safety device by reducing the command speed.
In addition, without lowering the command speed, the frequency limit value may be raised to prevent a cliff fall, or the control gain may be lowered.
As described above, the means for detecting the transition of the contact state by the change of the driving frequency has been described, but other than this, it can be similarly detected by the change of the speed deviation, the driving voltage signal and the vibration detection signal.

With reference to FIG. 7, a control device having a function of detecting a change in contact state based on a speed deviation, a drive voltage signal, and a vibration detection signal will be described.
7A shows an example of detecting a change in speed deviation information, FIG. 7B shows an example of detecting a change in driving voltage signal, and FIG. 7C shows an example of detecting a change in vibration detection signal. It is.
Each control device can basically apply the method described in FIGS. 4 to 6 in the same manner except that the information for detecting the change in the contact state is different.
Therefore, the detailed description is omitted, and only the configuration of the detection unit will be described.
As shown in FIG. 7A, the deviation information from the speed deviation detector 602 is detected by the deviation detector 613, and the difference from the deviation information read from the memory 611 is calculated by the comparator 612. .
Since the transfer characteristics of the motor change with the transition of the contact state, the deviation information changes. When the difference value of the deviation information exceeds the threshold value, the controller 601 detects the transition of the contact state.

As shown in FIG. 7B, the drive voltage signal from the drive circuit 606 is detected by the voltage detection unit 614, and the difference from the drive voltage information read from the memory 611 is calculated by the comparator 612. .
Since the drive frequency of the motor changes with the transition of the contact state, the amplitude of the drive voltage signal changes based on the relationship with the electrical resonance frequency of the drive circuit 606.
When the difference value of the drive voltage information exceeds a threshold value, the controller 601 detects the transition of the contact state.

As shown in FIG. 7C, the vibration detection signal from the vibration detection electrode 615 is detected by the vibration detection unit 616, and the difference from the vibration detection information read from the memory 611 is calculated by the comparator 612. The
The vibration detection electrode 615 is provided in a different area from the electrode used for driving the motor, and the change in the driving state of the motor can be detected by the amplitude of the detection signal from this electrode.
When the difference value of the vibration detection information exceeds a threshold value, the controller 601 detects the transition of the contact state.

[Example 2]
As Example 2 of the present invention, the configuration near the contact portion will be described with reference to FIG.
FIG. 3 is a cross-sectional view cut along a plane including the central axis, and the right side of the figure is the outer diameter side of the ring shape. Reference numeral 100 denotes a vibrating body, and 110 denotes a driven body.
Here, the vibrating body and the driven body are in contact with each other by the motor pressure acting in the direction of the arrow in the figure.
As in the first embodiment, the contact body 113 (a) arranged on the innermost peripheral side is the first contact body, and the second and third contact bodies are spare contact bodies in order toward the outer periphery. Be placed.
This embodiment differs from the configuration of FIG. 2 in that the frictional contact surface on the vibrating body 100 side is inclined in the radial direction. The contact surface of the driven body 110 is the same as the structure shown in FIG. 2, and the friction contact surfaces of the three contact bodies exist in substantially the same plane perpendicular to the motor rotation axis.

As described above, the friction contact surface on the vibrating body 100 side is inclined in the radial direction with respect to the three friction contact surfaces on the driven body 110 side. Therefore, as the diameter increases, the vibration body and the driven body Both sides are separated.
In this embodiment, since the gradient of the inclination (θ in the figure) is constant, the distance between the two contact surfaces increases linearly with respect to the diameter.

The initial contact part in Example 2 will be described.
At the start of driving, the first contact body 113 (a) is in contact, and the first contact body 113 (a) receives the driving force from the vibrating body 100.
However, when the value of the gradient θ of the contact surface is small, the first contact body 113 (a) does not necessarily handle the total motor pressure.
That is, as shown in FIG. 3, when the first contact body 113 (a) is elastically deformed by the motor pressure in the motor axial direction, the friction contact surface of the second contact body 113 (b) slightly forms an initial contact portion. It is possible that
However, if the total motor pressure is distributed approximately evenly between the two contact bodies 113 (a) and 113 (b) in the initial contact state, the above-described unstable contact state is induced. Therefore, the second contact body 113 (b) must not reach the contact surface pressure that sufficiently transmits the frictional force.
As a guide, the actual contact area generating the contact surface pressure in the second contact body 113 (b) is less than about 50% of the first actual contact area.

Subsequently, the transition of the contact state will be described.
First, the friction contact surface of the first contact body 113 (a) gradually wears with the driving from the initial contact state, and gradually shifts to a contact state with which it is familiar.
Then, as wear progresses while maintaining a stable driving state, the contact surface of the second contact body gradually increases the contact area.
When the contact surface of the second contact body starts to contact the outer peripheral side, the two contact bodies share the total motor pressing force and shift so as to generate a frictional force corresponding to the pressing force. Subsequent changes in the contact state are the same as in the modification of the first embodiment shown in FIG.
Here, in particular, a description of the contact start of the third contact body 113 (c) will be added. Depending on the magnitude of the gradient θ, the contact is not necessarily started after the transition from the first contact body described in the previous stage to the contact state of the first and second contact bodies is completed.
That is, the contact state may be shifted so that the contact surfaces of the second and third contact bodies gradually increase the contact area at the same time.

100: Vibrating body 110: Driven body 113: Contact body 114: Friction contact surface 115: Main body

Claims (10)

A vibrator having an electromechanical energy conversion element;
A driven body having a plurality of contact bodies including at least a first contact body and a second contact body in contact with the vibrating body;
By applying an alternating signal to the electro-mechanical energy conversion element, the driven body is frictionally driven by vibration excited by the vibrating body, and the driven body is moved relative to the vibrating body. A device,
The distance between the first contact body and the vibrating body facing the first contact body is the distance between the second contact body and the vibrating body facing the second contact body. The vibration type driving device is characterized by being smaller than the distance. The driven body has a third contact body in contact with the vibrating body,
The distance between the third contact body and the vibrating body facing the third contact body is greater than the distance between the second contact body and the vibrating body facing the second contact body. The vibration type driving device according to claim 1, wherein the vibration type driving device is large. The vibration type driving device is a rotary vibration type driving device,
The plurality of contact bodies are arranged in the order of the first contact body and the second contact body from the inner diameter side to the outer diameter side of the main body portion of the driven body. The vibration type driving device described in 1. A vibrator having an electromechanical energy conversion element;
A driven body having a plurality of contact bodies including at least a first contact body and a second contact body in contact with the vibrating body;
By applying an alternating signal to the electro-mechanical energy conversion element, the driven body is frictionally driven by vibration excited by the vibrating body, and the driven body is moved relative to the vibrating body. A device,
As the friction drive proceeds from the initial stage of the friction drive, the plurality of contact bodies can start contact with the vibrating body sequentially or step by step from the first contact body to the second contact body. It is comprised in the vibration type drive device characterized by the above-mentioned. In the initial stage of the friction drive, the plurality of contact bodies other than the first contact body do not contact the vibrating body, and contact in stages as the friction drive proceeds.
Alternatively, the area in contact with the vibrating body is smaller than the area in contact with the vibrating body of the first contact body, and the area in contact with the vibrating body sequentially increases as the friction drive proceeds. The vibration type driving device according to claim 4. The vibration type driving device is a rotary vibration type driving device,
From the inner diameter side to the outer diameter side of the main body portion of the driven body, the plurality of contact bodies are arranged in the order of the first contact body and the second contact body,
As the friction drive progresses from the initial stage of the friction drive, the first contact body on the inner diameter side is in contact with the vibrating body stepwise from the inner diameter side to the outer diameter side. 6. The vibration type driving device according to claim 4, wherein the vibration type driving device protrudes from the second contact body. The vibrating body and the driven body are:
The distance between the first contact body and the vibrating body facing the first contact body is the distance between the second contact body and the vibrating body in contact with the second contact body. 6. The vibration type driving device according to claim 4, wherein the vibration type driving device is provided to be smaller. A step is provided in a portion of the vibrating body facing the driven body,
In the step, the vibration is such that the distance between the first contact body and the vibrating body facing the first contact body is in contact with the second contact body and the second contact body. The vibration type driving device according to claim 1, wherein the vibration type driving device is formed so as to be smaller than a distance from the body. A detection means for detecting a contact state with the vibrating body in the plurality of contact bodies;
The vibration type drive according to any one of claims 1 to 8, wherein a remaining driveable time due to wear in the plurality of contact bodies is estimated based on a contact state detected by the detection means. apparatus.   The vibration type driving apparatus according to claim 9, wherein the detection unit detects the contact state based on any one of a driving frequency, a speed deviation, a driving voltage signal, and a vibration detection signal.

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