JP2002233173A - Driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driver which can suppress disorder of a displacement of an electromechanical transducer and suppress electromagnetic noise. SOLUTION: The driver comprises the electromechanical transducer, a drive friction element fixed to one end in the expanding direction of the electromechanical transducer, an engagement element engaged with the drive friction element by a frictional force, and a drive circuit which applies a drive voltage to the electromechanical transducer for moving an engagement member. The drive circuit applies a drive voltage to the electromechanical transducer, so as to have a displacement Xp of the electromechanical transducer expressed by a equation Xp=-Xpo sin(2π.fdt)+sin(2π.2fdt)/b} (1).

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 using an electromechanical transducer such as a piezoelectric element.

[0002]

2. Description of the Related Art Conventionally, there is a driving device for moving a moving body by utilizing expansion and contraction of a piezoelectric element. FIG. 1 shows the principle of a driving device using a piezoelectric element. As shown in FIG.
The driving device 2 includes a driving shaft 6 at one end of the piezoelectric element 4 in the expansion and contraction direction.
And the other end is fixed to the pedestal 3. The moving body 5 is frictionally engaged with the drive shaft 6 and can move along the drive shaft 6.

[0003] For example, the piezoelectric element 4 of the driving device 2
A drive voltage having a sawtooth waveform as shown in FIG. First, when the applied voltage is gradually changed, as shown in FIG. 1B, the piezoelectric element 4 moves in a direction to increase its thickness, and the drive shaft 6 moves in the steering direction.
Accordingly, the moving body 5 moves together with the drive shaft 6.

Next, when the application of the voltage to the piezoelectric element 4 is rapidly changed, as shown in FIG.
Rapidly shrinks, and the drive shaft 6 moves in the return direction. At this time, the moving body 5 stays there and overcomes the friction with the drive shaft 6 and does not move. Therefore, as a result, the moving body 5 moves rightward with respect to the drive shaft 6 as shown in FIG.

[0005] As described above, the sawtooth waveform of the drive voltage applied to move the moving body 5 is obtained by superimposing a sine wave as represented by the following equation (14) when Fourier-expanded. Things.

[0006]

(Equation 10)

[0007]

However, the driving waveform in the conventional driving method increases the cost of the driving circuit, and includes a higher-order sine wave in the voltage waveform as shown in the above equation (14). In many cases, frequency components near the resonance frequency of the piezoelectric element are also included.

The frequency component near the resonance frequency disturbs the displacement waveform of the piezoelectric element and adversely affects the movement of the moving body. A high-order sine wave included in the drive voltage having a sawtooth waveform causes electromagnetic noise and has a practical problem.

More specifically, when a driving voltage having a sawtooth waveform as shown in FIG. 1E is applied to the piezoelectric element 4, the displacement of the piezoelectric element 4 becomes as shown by 4a in FIG. To
Where the material contracts rapidly, the displacement is disturbed. The disturbance of the displacement causes the movement of the moving body 5 to be disturbed as shown by 5a.

[0010] Therefore, a technical problem to be solved by the present invention is to provide a driving device capable of suppressing disturbance of displacement of an electromechanical transducer and suppressing generation of electromagnetic noise.

[0011]

The present invention provides a driving device having the following configuration in order to solve the above technical problems.

The drive device includes an electromechanical transducer, a drive friction member fixed to one end of the electromechanical transducer in the direction of expansion and contraction, an engagement member engaged with the drive friction member by frictional force, And a drive circuit for applying a drive voltage to move the engaging member to the electromechanical conversion element. Then, the drive circuit, the displacement X _p of the electromechanical conversion element as represented by the following equation (1), applies the driving voltage to the electromechanical transducer.

[0013]

[Equation 11]

In the formula, X _p0 , f _d , t, and b indicate the following. X _p0 : amplitude of an arbitrary electromechanical transducer f _d : arbitrary driving frequency t: time b: constant satisfying 2 <b <8

In the above configuration, the electromechanical conversion element is
It is an element such as a piezoelectric element or an electrostrictive element. In the driving device, the displacement of the electromechanical transducer is not required up to a high-order sine wave and is sufficient up to a second-order sine wave, and the displacement is represented by the above equation (1). Since the displacement of the electromechanical transducer at this time has a substantially sawtooth waveform,
The engagement member can be driven. In addition, since a high-order sine waveform is not included, it is possible to exclude a frequency component near a resonance frequency of the electromechanical transducer, and the displacement of the electromechanical transducer is not disturbed, thereby generating electromagnetic noise. Absent.

According to the above configuration, the drive voltage does not generate electromagnetic noise and does not disturb the movement of the engagement member.

The driving device of the present invention can be specifically configured in various modes as described below.

Preferably, the drive circuit applies the drive voltage represented by the following equation (2) to the electromechanical transducer.

[0019]

(Equation 12)

(Where V ₀ , f _d , t, b, | G (f _d )
|, Θ (f _d ) indicates the following. V ₀ : arbitrary voltage f _d : arbitrary driving frequency t: time b: constant satisfying 2 <b <8 | G (f _d ) |: gain of transfer function θ (f _d ): phase of transfer function.

The gain | G (f _d ) | of the transfer function and the phase θ
(f _d ) is represented by the following equations (15) and (16), respectively.

[0022]

(Equation 13)

In equations (15) and (16), A (f_d)
And B (f_d) Is the electric machine represented by the following equation (3).
Voltage-displacement transfer function G (f_d) Is the real part A
(f _d) And the imaginary part B (f_d) And G (f_d) = A (f_d) +
iB (f_d) Is derived.

[0024]

[Equation 14]

[0025] In formula, is f _s resonant frequency of the electromechanical transducer, the Q _m is a machine quality factor of the electromechanical transducer.

According to the above configuration, since the drive voltage that takes into account the change due to the transfer function between the drive voltage applied by the drive circuit and the electromechanical transducer is clarified,
The driving of the driving device can be facilitated.

Preferably, the driving circuit applies the driving voltage represented by the following equation (4) to the electromechanical transducer.

[0028]

(Equation 15)

In the formula, V ₀ , f _d , t, and b indicate the following. V _0: arbitrary voltage _{f d:} f _{d <drive} frequency (the resonant frequency of _{f s} is the electro-mechanical conversion element) that satisfies _f s / 3 t: time b: 2 constants satisfying <b <8

According to the above configuration, the driving frequency f _d is f _d
<Range satisfying f s _{/ 3,} i.e. in the small range as compared with the resonance frequency of the electromechanical transducer, a voltage is applied that does not depend on the transfer function between the drive voltage and the electro-mechanical conversion element is made possible.

Preferably, the electromechanical transducer comprises a first electromechanical transducer and a second electromechanical transducer coupled in the direction of expansion and contraction, and the drive circuit comprises the first electromechanical transducer. The element displacement X _p1 is given by the following equation (5).
And the displacement X of the second electromechanical transducer
_The drive voltage is applied to the first and second electromechanical transducers such that _p2 is represented by the following equation (6).

[0032]

(Equation 16)

In the formula, X _p0 , f _d , t, and b indicate the following. X _p0 : amplitude of an arbitrary electromechanical transducer f _d : arbitrary driving frequency t: time b: constant satisfying 2 <b <8

According to the above configuration, the first and second electromechanical transducers are connected in series, for example, in series, and
By giving the sine waveform displacements represented by Expressions (5) and (6), the displacement of the entire electromechanical transducer can be made a sine waveform up to the second order.

Preferably, the electromechanical transducer comprises a first electromechanical transducer and a second electromechanical transducer, and the drive circuit comprises a drive voltage V ₁ represented by the following equation (7). Is applied to the first electromechanical transducer,
The driving voltage V ₂ represented by the following equation (8) is applied to the second electro-mechanical conversion element.

[0036]

[Equation 17]

In the formula, V ₀ , f _d , t, b, A ₁ and A ₂ indicate the following. V ₀ : arbitrary voltage f _d : arbitrary driving frequency t: time b: constant satisfying 2 <b <8 A ₁ : displacement amount per unit voltage of the first electromechanical transducer A ₂ : second electricity Displacement per unit voltage of mechanical transducer

According to the above configuration, the first and second electromechanical transducers are connected, for example, in series, and the driving voltages shown in equations (7) and (8) are applied, respectively. The same effect as when a drive voltage up to the secondary sine wave is applied can be obtained for the entire device. Further, it is possible to clarify the drive voltage that allows for the change due to the transfer function between the drive voltage applied by the drive circuit and the electromechanical transducer. Further, since the drive circuit can apply a drive voltage having a sine waveform, the configuration can be simplified.

Preferably, the drive circuit applies a drive voltage V ₁ represented by the following equation (9) to the first electromechanical transducer, and applies a drive voltage V ₂ represented by the following equation (10). Is applied to the second electromechanical transducer.

[0040]

(Equation 18)

In the formula, V ₀ f _d , t, and b indicate the following. V _0: arbitrary voltage _{f d:} f _{d <drive} frequency (the resonant frequency of _{f s} is the electro-mechanical conversion element) that satisfies _f s / 3 t: time b: 2 constants satisfying <b <8

According to the above configuration, the driving frequency f _d is f _d
<Range satisfying f s _{/ 3,} i.e. in the small range as compared with the resonance frequency of the electromechanical transducer, a voltage is applied that does not depend on the transfer function between the drive voltage and the electro-mechanical conversion element is made possible.

Preferably, the constant b is equal to a ratio (A ₁ / A ₂ ) of a displacement per unit voltage between the first electromechanical transducer and the second electromechanical transducer, and the drive circuit Applies a driving voltage V ₁ represented by the following equation (11) to the first electromechanical transducer, and applies the following equation (1)
The driving voltage V ₂ represented by 2) applied to the second electro-mechanical conversion element.

[0044]

[Equation 19]

In the formula, V ₀ ′, f _d , t, and b indicate the following. V ₀ ': any voltage _{f d:} f _{d <drive} frequency (the resonant frequency of _{f s} is the electro-mechanical conversion element) that satisfies _f s / 3 t: time b: 2 constants satisfying <b <8

According to the above configuration, by adjusting the amount of displacement of the electromechanical transducer, a single power source can be used for the drive voltage applied to the first and second electromechanical transducers.

Preferably, the drive circuit applies the drive voltage to the electromechanical transducer by a self-excited oscillation circuit.

According to the above configuration, the electromechanical transducer is provided with two
In order to apply a sinusoidal drive voltage to each,
Energy loss can be suppressed.

[0049] Preferably, the drive circuit, the relative displacement X _p is the equation of the electromechanical transducer (1), so that it can provide a phase shift θ as shown by the following equation (13) Phase adjusting means for adjusting the driving voltage, and adjusts a moving speed and a moving direction of the engaging member.

[0050]

(Equation 20)

In the formula, X _p0 , f _d , t, and b indicate the following. X _p0 : amplitude of an arbitrary electromechanical transducer f _d : arbitrary driving frequency t: time b: constant satisfying 2 <b <8

The phase adjusting means for adjusting the phase shift θ of the secondary sine wave is easily constructed, and the moving speed and moving direction of the engaging member can be easily adjusted.

[0053]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a driving device according to each embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows a driving device according to the first embodiment of the present invention. As shown in FIG.
The one end face of the piezoelectric element 14 which is an electromechanical transducer in the expansion and contraction direction is fixed to the base 13 and the other end face is fixed to the drive shaft 16 which is a drive member. Drive shaft 16
, A moving body 15 which is an engagement member is frictionally engaged with, and can move along a drive shaft 16.

Applying a driving voltage to the piezoelectric element 14
Therefore, the piezoelectric element expands and contracts, and the displacement X _pOccurs. Piezoelectric element
Displacement X of child 14_pIs transmitted to the drive shaft 16 and the drive shaft 16
Moves, the moving body 15 moves at a speed V_mMove with
You. The following equation (1) is obtained by superimposing sine waves up to the second order.
A substantially sawtooth waveform can be created by 7),
Displacement X of piezoelectric element_pThe situation is shown in FIG.

[0056]

(Equation 21)

As shown in FIG. 2, a substantially sawtooth waveform can be formed by combining sine waves up to the second order, and the driving device 10 is driven by the piezoelectric element 14 being displaced in a substantially sawtooth waveform. Can be.

Next, a description will be given of a second embodiment in which the magnitude of the secondary sine wave is changed in the above equation (17). In the driving device 10 of the present embodiment, one end of the piezoelectric element 14 in the expansion and contraction direction is fixed to the base 13, and the other end is connected to the driving shaft 16.
Fixed to. The moving body 15 is frictionally engaged with the drive shaft 16. The piezoelectric element 14 moves so that its displacement is represented by superposition of sine waves up to the second order, and is specifically represented by the following equation (1).

[0059]

(Equation 22)

[0060] As shown in FIG. 3 (a), the piezoelectric element 14 to the displacement X _p as represented by the equation (1), the drive shaft 16 is a drive member in accordance with this move, move body 15 is moved at a velocity _{V m.} Here, the above equation (1)
FIG. 3B shows the speed of the moving body 15 when the value of b is changed.
Shown in As shown in this graph, the moving velocity V _m of the moving body 15 changes, b in the range of 2 to 8, preferably if you take the value of 4, it is possible to maintain a large velocity of the moving body 15,
Speed performance can be increased.

Next, a third embodiment in which the phase of a sine wave is changed will be described. In the driving device 10 of the present embodiment, one end of the piezoelectric element 14 in the expansion and contraction direction is fixed to the pedestal 13, and the other end is fixed to the driving shaft 16. The moving body 15 is frictionally engaged with the drive shaft 16. The piezoelectric element 14 moves so that its displacement is represented by superposition of sine waves up to the second order, and is specifically represented by the following equation (18).

[0062]

(Equation 23)

[0063] As shown in FIG. 4 (a), when the displacement piezoelectric element 14 is shown by the number 24 of the _{X p,} the driving shaft 16 moves with this, the moving body 15, moves at a speed _{V m} I do. Moving object 15 when the value of phase θ in the above equation is changed
Is shown in FIG. 4 (b). As shown in this graph,
The moving speed _Vm and the direction of the moving body 15 change by changing the value of the phase θ, and the direction and speed of moving the moving body 15 can be controlled by adjusting the phase θ. Since the phase control using the phase θ is performed using software or the like, there is an advantage that the control can be easily performed.

Here, the details of the configuration of the piezoelectric element and the driving device specifically used in each embodiment will be described. The piezoelectric element is of a full electrode type laminated type using the d33 direction. The dimensions are 2 × 2 × 10 mm. Layer thickness 100 μm
And the number of layers is 100. The capacitance is 100 nF. As the configuration of the driving device, carbon was used for the driving shaft material. In this configuration, the resonance frequency of the piezoelectric element is 60 k
Hz.

[0065] the driving conditions at the time of driving is allowed to provide the displacement X _p represented by the equation (1) to the piezoelectric element 14,
The drive frequency is 10kHz, static displacement amount _{X p0} is 0.4μ
m (voltage 10 V).

Next, a fourth embodiment showing the relationship between the voltage applied to the piezoelectric element and the displacement will be described. In the driving device 10 of the present embodiment, one end of the piezoelectric element 14 in the expansion and contraction direction is fixed to the pedestal 13, and the other end is fixed to the driving shaft 16.
The moving body 15 is frictionally engaged with the drive shaft 16. The drive voltage V applied to the piezoelectric element 14 by the drive circuit 17
If the drive frequency f _d is sufficiently lower than the resonance frequency f _s of the piezoelectric element, outline of the displacement X _p and voltage V can be regarded as similar. However, as the frequency increases, the outline becomes different. This is because the transfer function of the displacement from the voltage of the piezoelectric element 14 is dependent on the drive frequency f _d.

The drive voltage and the displacement of the piezoelectric element have a relationship represented by the following equation (19) using a transfer function G (f _d ), and the transfer function G (f _d ) is represented by the following equation (3). ).

[0068]

(Equation 24)

In the above equation (3), the resonance frequency f _s
Is 60 kHz as described above. The piezoelectric element mechanical quality factor Q _m is the value of the piezoelectric material 50, because it is appropriate to use the value of 1 to 10 when the configuration of the drive device, using a Q m _{= 3.}

Here, in order to see the characteristics of the transfer function,
Drive frequency f_dOn the horizontal axis, and the gain of the transfer function
G (f_d) | And the phase θ (f_d) On the horizontal axis
Used. The gain and phase are represented by the above equation (3).
The transfer function to be calculated is represented by the real part
And imaginary part, A (f_d), B (f
_d). Specifically, the gain | G (f_d) |
Is the equation (15), and the phase θ (f_d) Is represented by equation (16).
It is.

[0071]

(Equation 25)

| G (f _d ) | and θ (f _d ) are respectively shown in FIG.
The graph has a change as shown in (b) and (c). This, in order to achieve the displacement X _p described above, it is necessary to apply a voltage in anticipation of the change due to the transfer function. Therefore, the drive voltage V is represented by the following equation (2). In this equation, b = 4 is used.

[0073]

(Equation 26)

[0074] In the driving device 10 shown in FIG. 5, moved by the drive circuit 17, by applying a driving voltage V of the above equation to the piezoelectric element 14, the piezoelectric element 14 in the displacement X _p shown in the equation (1) I do. Accordingly, the moving body 15 is driven.

However, in this method, it is necessary to sufficiently clarify the transfer function G of the piezoelectric element. In addition, in the case of mass production or the like, if this transfer function varies from unit to unit, it is necessary to individually adjust the transfer function. Therefore, a method for avoiding these is required.

FIG. 6 is a diagram for explaining a fifth embodiment in which the driving frequency is limited. In the driving device 10 of the present embodiment, one end of the piezoelectric element 14 in the expansion and contraction direction is fixed to the pedestal 13, and the other end is fixed to the driving shaft 16. Drive shaft 1
A moving body 15 is frictionally engaged with 6. FIGS. 6B and 6C show the relationship between the drive frequency and the gain and phase of the transfer function derived as described above. FIG.
(B) _f d as shown in _<f s / 3 range, namely,
So long as the drive frequency _{f d} is less 20kHz, | G (f
_d ) | = 1. Similarly, in the range of _f d _{<f s} / 3 as shown in FIG. 6 (c), it can be regarded as θ _{(f d)} = 0. Thus, when the driving frequency is limited, the driving voltage V is expressed by the following equation (4). However, the range of the drive frequency f _d is the piezoelectric element mechanical quality factor Q _m
Depends on.

[0077]

[Equation 27]

The driving voltage V represented by the above equations (2) and (4) is difficult to generate with a relatively simple electric circuit. On the other hand, it is possible to generate the primary sine wave and the secondary sine wave in the expression shown in Expression (4) independently with a relatively simple electric circuit. Therefore, the piezoelectric element is divided into two blocks in series, and the above equation (4) is assigned to each block.
In By applying a primary sinusoidal and secondary sinusoidal expression represented as a whole a piezoelectric element, it is possible to obtain the displacement X _p represented by formula represented by the above formula (1).

FIG. 7 shows a driving device 12 according to the sixth embodiment.
Is shown. The driving device 12 divides the piezoelectric element into two blocks and applies a primary sine wave and a secondary sine wave to each block. Specifically, as the piezoelectric element 20, the layer of the multilayer piezoelectric element is divided into two blocks, a first block 22 and a second block 24. As described above, since the number of stacked piezoelectric elements 20 is 100, the first block 2
The total number of layers of 2 and the second block 24 is 100. Drive circuits 26 and 28 applies a driving voltage V ₁ and V ₂ in each of the second blocks 24, which is the first of the first block 22 is a piezoelectric element, a second piezoelectric element connected in series. Driving voltages V ₁ is the primary sine term of the driving voltage of the equation (2), the driving voltage V ₂ is the secondary sine term of the above equation (2). These are specifically represented by the following equations (7) and (8).

[0080]

[Equation 28]

[0081] Figure 8 shows a seventh embodiment the drive frequency _{f d} is limited to a range of _f d _<f s / 3. In the present embodiment, | G (f _d ) | = 1 and θ (f _d ) = 0 can be regarded as described above, so the drive circuit 36 generates the drive voltage V represented by the following equation (9). applying a ₁ to the first block 32 is a first piezoelectric element, the driving circuit 38 applies a driving voltage V ₂ represented by the following equation (10) to the second block 34 is a second piezoelectric element . As a result, the piezoelectric element 3
0 as a whole, can be obtained a displacement X _p shown in Equation (1).

[0082]

(Equation 29)

FIG. 9 shows a driving device according to the eighth embodiment.
As shown in FIG. 9, the present driving device 12b includes a piezoelectric element 40
Is divided so that the displacement amount of each layer of the laminated piezoelectric element becomes 4: 1. Specifically, the piezoelectric element 40 is provided so that the ratio of the number of layers of the first block 42 and the second block 44 is 4: 1, that is, the first block has 80 layers and the second block has 20 layers. By providing the piezoelectric element 40 in this manner, the driving circuit 46
Applying a driving voltages _{V 1} represented in 2 by the following equation (11). The drive circuit 48 applies a drive voltage _{V 2} to the second block 44 is expressed by the following equation (12). Therefore, the driving circuits 46 and 48 can be obtained from a single power supply.

[0084]

[Equation 30]

In addition, instead of using a laminated type piezoelectric element and setting the ratio of the displacement amount to the number of laminations of 4: 1, the other lengths are the same.
The same effect can be obtained even when the electric field strength is quadrupled.

When the piezoelectric element is driven with a sinusoidal waveform in a region where it can be treated as a capacitive load, the energy can be very low. However, when the piezoelectric element is driven with a sawtooth waveform or a waveform represented by the above equation (2), energy loss is inevitable because the waveform is not a sine wave.
From this, low power consumption can be cited as a great advantage of dividing the piezoelectric element into two blocks and driving each of the blocks with a sine wave.

FIG. 10 shows a configuration of a driving device 12c according to a ninth embodiment using the electric circuit shown in FIG. 10 in order to achieve this. In the driving device 12c, a self-excited oscillation circuit 60 is used as a driving circuit to generate a sine wave. The driving voltage V is calculated by the self-excited oscillation circuit 60.
It is applied to each of the first block 52 and the second block 54. Self-oscillating circuit 60, a power source 65 in common, a pulse 66 of frequency _{f d} is applied to the first block 52 is induced by the coil 63 through the switch 61.
Similarly, pulse 68 of frequency 2f _d is induced by the coil 64 through the switch 62, the second block 54
Is applied to Inductance L of the self-excited oscillation circuit in this case may be set so as self-oscillation frequency is f _d and 2f _d. Specifically, it may be set so that each inductance L ₂ of the inductance L ₁ and the coil 64 of the coil 63 becomes a value represented by the following equation (21) and (22).

[0088]

(Equation 31)

Since the circuit 60 is driven by a sine wave,
By using this circuit, energy loss can be suppressed.

The present invention is not limited to the above embodiment, but can be implemented in various other modes.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a driving device using a piezoelectric element.

FIG. 2 is a diagram showing a driving device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a driving device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a driving device according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a driving device according to a fourth embodiment of the present invention.

FIG. 6 is a view showing a driving device according to a fifth embodiment of the present invention.

FIG. 7 is a diagram illustrating a configuration of a driving device according to a sixth embodiment of the present invention.

FIG. 8 is a diagram illustrating a configuration of a driving device according to a seventh embodiment of the present invention.

FIG. 9 is a diagram illustrating a configuration of a driving device according to an eighth embodiment of the present invention.

FIG. 10 is a diagram illustrating a configuration of a driving device according to a ninth embodiment of the present invention.

[Explanation of symbols]

 2 Driving device 3 Pedestal 4 Piezoelectric element 5 Moving body 6 Driving shaft 10 Driving device 12, 12a, 12b, 12c Driving device 13 Pedestal 14 Piezoelectric element 15 Moving body 16 Drive shaft 20, 30, 40, 50 Piezoelectric elements 22, 32, 42, 52 First block 24, 34, 44, 54 Second block 36, 38, 46, 48 Driving circuit 60 Self-excited oscillation circuit 61, 62 Switch 63, 64 Coil 65 Power supply 66, 68 pulses

Claims (9)

[Claims] An electromechanical transducer, a drive friction member fixed to one end of the electromechanical transducer in a direction of expansion and contraction, an engagement member engaged with the drive friction member by frictional force, and in the driving device comprising a driving circuit for applying a driving voltage to move the engaging member to the conversion element, wherein the drive circuit, the displacement X _p of the electro-mechanical conversion element is represented by the following formula (1) As described above, the drive device applies the drive voltage to the electromechanical transducer. (Equation 1) ( _Where X _p0 , f _d , t, and b indicate the following: X _p0 : amplitude of any electromechanical transducer f _d : any drive frequency t: time b: 2 <b <8 constant) 2. The drive device according to claim 1, wherein the drive circuit applies the drive voltage represented by the following equation (2) to the electromechanical conversion element. (Equation 2) (Where V ₀ , f _d , t, b, | G (f _d ) |, θ (f _d ) indicate the following: V ₀ : arbitrary voltage f _d : arbitrary driving frequency t: time b: constant satisfying 2 <b <8 | G (f _d ) |: gain of transfer function represented by the following equation (3) θ (f _d ): phase of transfer function represented by the following equation (3) [Equation 3] (Where f _s and Q _m indicate the following: f _s : resonance frequency of the electromechanical transducer element Q _m : mechanical quality factor of the electromechanical transducer element) 3. The drive device according to claim 2, wherein the drive circuit applies the drive voltage represented by the following equation (4) to the electromechanical transducer. (Equation 4) _{(Wherein, V 0, f d, t} , b indicates the following: _{V 0:.} Any voltage _{f d:} f _{d <driving} frequency satisfying _{f s} / 3 _(f s is the electromechanical transducer Resonance frequency) t: time b: constant satisfying 2 <b <8) 4. The electro-mechanical conversion device according to claim 1, wherein the electro-mechanical conversion device includes a first electro-mechanical conversion device and a second electro-mechanical conversion device coupled in the direction of expansion and contraction. Displacement X
_The first and second electromechanical transducers are _{defined such} that _p1 is represented by the following equation (5) and displacement _{Xp2 of} the second electromechanical transducer is represented by the following equation (6). The driving device according to claim 1, wherein the driving voltage is applied. (Equation 5) ( _Where X _p0 , f _d , t, and b indicate the following: X _p0 : amplitude of any electromechanical transducer f _d : any drive frequency t: time b: 2 <b <8 constant) 5. The electro-mechanical conversion element comprises a first electro-mechanical conversion element and a second electro-mechanical conversion element coupled in a direction of expansion and contraction, and the driving circuit is represented by the following equation (7). Drive voltage V
₁ is applied to the first electro-mechanical conversion element, the driving of claim 4, wherein the driving voltage V ₂ represented by the following equation (8) and applying to said second electromechanical transducer apparatus. (Equation 6) (Where V ₀ , f _d , t, b, A ₁ , A ₂ indicate the following: V ₀ : arbitrary voltage f _d : arbitrary driving frequency t: time b: 2 <b <8 Satisfaction constant A ₁ : Displacement per unit voltage of the first electromechanical transducer A ₂ : Displacement per unit voltage of the second electromechanical transducer 6. The driving circuit is represented by the following equation (9).
Drive voltage V₁Is applied to the first electromechanical transducer.
And a driving voltage V represented by the following equation (10). _TwoThe said
2. The method according to claim 1, wherein the voltage is applied to the electromechanical transducer.
Item 6. The driving device according to Item 5. (Equation 7)(Where V₀, F_d, T and b indicate the following. V₀: Arbitrary voltage f_d: F_d<F_sDrive frequency (f_sIs
T: time b: constant satisfying 2 <b <8) 7. The constant b is equal to the ratio (A ₁ / A ₂ ) of the amount of displacement per unit voltage of the first electromechanical transducer and the second electromechanical transducer, and the drive circuit ,
The driving voltages V ₁ represented by the following equation (11) is applied to the first electro-mechanical conversion element, applying a drive voltage V ₂ represented by the following equation (12) to said second electromechanical transducer 7. The driving device according to claim 6, wherein the driving is performed. (Equation 8) _{(Wherein, V 0 ', f d,} t, b is _{V 0} indicates that:.': Any voltage _{f d: f d <f s} / 3 to satisfy the drive frequency _{(f s} is the electro-mechanical conversion Element resonance frequency) t: time) 8. The driving circuit includes a self-excited oscillation circuit,
The drive device according to claim 4, wherein the drive voltage is applied to the electromechanical conversion element. 9. The driving circuit according to claim 1, wherein the displacement Xp of the electromechanical transducer is _defined by the following equation (1) with respect to the equation (1).
Phase adjusting means for adjusting the driving voltage so that the phase shift θ can be provided as shown in 3);
2. The driving device according to claim 1, wherein a moving speed and a moving direction of the engaging member are adjustable. (Equation 9) ( _Where X _p0 , f _d , t, and b indicate the following: X _p0 : amplitude of any electromechanical transducer f _d : any drive frequency t: time b: 2 <b <8 constant)