JPH0620241A - Head actuator - Google Patents

Abstract

PURPOSE:To provide a downsized head actuator having high control frequency in which spacing angle between a head and a tape is substantially nullified and deflection angle (amplitude) is increased while ensuring high positional accuracy. CONSTITUTION:The head actuator is constructed such that a mover 6 is brought into pressure contact with an oscillator 3 secured completely at a supporting position through a pressurizing mechanism section 8 carried on a guide shaft 7 at a ridge part of a resilient member 1 having square or triangular cross-section applied with first and second piezoelectric bodies 2a, 2b. When the mover 6 is driven along the guide shaft 7, spacing angle between a head 10 and a tape can be substantially nullified and since the deflection angle is large and not susceptible to mechanical resonance frequency, high response can be ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small head actuator for generating driving force by using elastic vibration of a piezoelectric body used in VTR equipment and the like.

[0002]

2. Description of the Related Art In recent years, in VTR equipment, the quality of recorded / reproduced images has been improved, the special reproduction function has been enhanced, and the video track width has been narrowed with the increase in recording density due to the progress of magnetic materials. A head actuator capable of doing so is desired. Hereinafter, a conventional piezoelectric head actuator of a composite bimorph and a parallel spring bimorph will be described.

FIG. 15 is a perspective view of a head actuator having a composite bimorph structure developed by Ampex Corporation.
FIG. 16 is a diagram showing the operating principle thereof. In the figure,
31 is a bimorph structure piezoelectric body, 32, 33, 34, 35
Is an actuator electrode, 36 is a sensor electrode, 37 is a support, and 38 is a head. In the head actuator configured as shown in the figure, actuator electrodes 32 and 34 and 33 and 35 are connected to each other, and actuator electrodes 32 and 3 are connected.
When bending is generated in one direction in 3, the tip ends of the piezoelectric body 31 are bent in the opposite directions by the actuator electrodes 34 and 35 connected in the opposite directions, so that they are deformed into an S shape as a whole. As a result, the head 38 provided at the tip of the tape 3
The spacing angle θ with respect to 9 can be made significantly smaller than that of a head actuator having a single bimorph structure. In addition, the sensor electrode 36 detects the electric charge generated from the strain due to the bending of the piezoelectric body 31, and thus the head 38
Used to control the position of the.

FIG. 17 is a perspective view of a head actuator having a parallel spring bimorph structure. FIG. 18 is a diagram showing the operating principle. From the figure, two piezoelectric elements 40 and 41 having a bimorph structure are arranged in parallel, a flexible head holder 42 having flexibility in the bending direction is provided at the tip, and a head 38 is attached to the tip. There is. From FIG. 18, when a DC voltage is applied to the piezoelectric elements 40 and 41, the tips are displaced according to the equation (1).

[0005]

[Equation 1]

Here, d ₃₁ is the piezoelectric constant, (13) is the length of the piezoelectric element, t is the thickness of the piezoelectric element, and V is the applied voltage.

Further, the mechanical resonance frequency f of the piezoelectric elements 40 and 41 follows (Equation 2).

[0008]

[Equation 2]

Where ρ is the density and s ₁₁ is the elastic constant. When the piezoelectric elements 40 and 41 are displaced due to the above relationship,
The flexible head holder 42 is deformed so as to be parallel to the tape 39. Therefore, compared with the composite bimorph structure of FIG. 15, the length of the piezoelectric element contributing to bending can be effectively increased, and the flexible head holder 42 can be used.
As a result, the head 38 moves in parallel, so that the spacing angle θ can be made almost zero.

[0010]

However, in the above-mentioned conventional structure, there is a problem in that the head actuator of the composite bimorph structure or the parallel spring type bimorph structure becomes large in size. According to the relationship between (Equation 1) and (Equation 2), the displacement amount ξ is proportional to the square of the ratio (l / t) of the length and thickness of the piezoelectric element. On the other hand, the resonance frequency f is proportional to the square of the thickness and the length of the piezoelectric body (t / l ² ). For example, the length l of the piezoelectric element is 20 mm, the thickness is 1 mm, and d ₃₁
≈ -10 ^-10 (m / v), Young's modulus s ₁₁ ≈ 10 ¹¹ (N /
m ² ), density ρ = 7.8 × 10 ³ (kg / m ³ ), voltage V = 1 Kv, displacement ξ≈300 μm, resonance frequency f≈1
It is possible to obtain about 400 Hz. However, in order to increase the amount of displacement, it is necessary to increase the element length of the piezoelectric body, reduce the thickness of the piezoelectric body, apply a high DC voltage, or develop a material with a large piezoelectric constant d _31. I won't. In addition, in order to improve the resonance frequency, it is necessary to have a shape that is contrary to the expansion of the displacement amount, such as shortening the piezoelectric body length or thickening the piezoelectric body thickness. It has become difficult to satisfy both at the same time.

An object of the present invention is to provide a head actuator that solves the above problems.

[0012]

In order to achieve this object, a head actuator of the present invention comprises a rod-shaped vibrating body having a quadrangular cross-sectional shape in which piezoelectric bodies are provided on at least one pair of intersecting planes, and a quadrangular vibration. The first and second piezoelectric bodies are composed of a pressurizing mechanism section for pressing a moving body provided on a guide shaft to the ridge of the body and a position detecting section such as an optical type or a strain detecting element for knowing the position of the moving body. Driving method by the combined vibration excited by, or moving the moving body in one direction by applying AC voltage to the piezoelectric body on one side and moving the moving body in the opposite direction by switching the AC voltage to the other piezoelectric body. The above-mentioned problems are solved by a driving method of moving.

[0013]

With this configuration, since the pressure applied to the moving body and the vibrating body is not a surface but a point or a linear shape, there is no restriction on the plane accuracy and parallelism of the moving body and the vibrating body, and mass productivity and low cost are reduced. It can be easily scratched. Further, the control frequency is not limited by the mechanical resonance frequency as in the conventional bimorph structure. The elastic vibration due to the resonance phenomenon of the piezoelectric element attached to the vibrating body is transmitted to the moving body via the friction force, so that the driving voltage can be reduced and the moving body can be driven at high speed. Further, since the head moves on the guide shaft, the swing width of the head is not limited by the structure and the characteristics of the piezoelectric material, and the spacing angle of the head can be made almost zero.

Further, as this driving method, since the moving body is pressed to the ridge line portion of the vibrating body having an angle with respect to the vibration displacement in the X and Y directions, the moving body is detected by the cosine component of the displacement amount of the vibration. It can be driven and the moving body can be driven in one direction only by the vibration of the piezoelectric body on one side in the X and Y directions, and the moving direction can be reversed only by switching the AC voltage so as to excite the vibration in the other piezoelectric body. It is possible. Still another driving method is to apply alternating voltages having different phases to the piezoelectric bodies in the X and Y directions at the same time to excite the vibration of an elliptical locus on the ridge of the vibrating body and change the sign of the phase. It is also possible to easily change the moving direction of.

[0015]

【Example】

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a head actuator according to a first embodiment of the present invention. In FIG. 1, 1 is an elastic body having a quadrangular cross-sectional shape, 2a is a first piezoelectric body (not shown), 2b is a second piezoelectric body, and the elastic body 1 has a first piezoelectric body 2a and a second piezoelectric body 2a. The vibrating body 3 is configured by laminating 2b. Further, 4 is a support hole, 5 is a support member, 6 is a moving body, 7
Is a guide shaft, 8 is a pressing mechanism provided on the guide shaft, 9 is a position detector including an optical position detecting element, and 10 is a signal detecting head. FIG. 2 is a diagram showing the displacement distribution of the primary free vibration of the rod, and 11 is a node corresponding to the position of the support hole 4, and in this case, 0.2 from both ends of the vibrating body 3.
The position is 24 l (l: vibrator length). From FIG. 1, the moving body 6 is pressed and contacted by the pressing mechanism portion 8 including the spring provided on the guide shaft 7 at the maximum position of the vibration displacement amount in the central portion of the vibrating body 3 at the ridge portion of the vibrating body 3. There is. The vibrating body 3 is made of a support member 5 such as a plastic pin having a low Young's modulus or a material having a low sound velocity, and is supported and fixed by the support hole 4. At this time, the support hole 4 is used as the vibrating body 3 in the X and Y directions.
It is preferable to provide them symmetrically in order to equalize their rigidity, but this is not the case when the influence of the support holes 4 can be ignored.

Next, the driving principle will be described with reference to the operation explanatory diagrams of FIGS. 3 and 4A and 4B. FIG. 3 is a driving principle diagram when the combined vibration of the first and second piezoelectric bodies 2a and 2a is used, and FIG. 4 is a diagram when the first and second piezoelectric bodies 2a and 2a are used as independent vibrations. It is a driving principle diagram of.

In FIG. 3, an AC voltage v ₁ represented by (Equation 3) is applied to the first piezoelectric body 2a to excite vibration in the X direction.
Further, the second piezoelectric body 2b excites the vibration in the Y direction by the AC voltages v ₂ represented by (Equation 4) and having different π / 2 phases.

[0019]

[Equation 3]

[0020]

[Equation 4]

Here, V ₀ is the instantaneous value of the AC voltage, ω is the angular frequency, and t is the time. As a result, bending vibration having an elliptical locus represented by (Equation 5) is excited over the entire circumference of the vibrating body 3. As an example, the state of an elliptical locus is shown by the arrow in FIG.

[0022]

[Equation 5]

Here, ξ is an amplitude value of bending vibration, and ξ ₀ is an instantaneous value of bending vibration. Due to the vibration of the elliptical locus, the ridge line portion of the vibrating body 3 is pressed against the moving body 6 by the pressing spring of the pressing mechanism portion 8 and is driven in the moving direction of the elliptical locus by the frictional force. Further, by changing the phase to ± π / 2 as shown in (Equation 4), the moving direction of the moving body 6 can be reversed.

As another driving method, FIG. 4A shows how the ridge line portion of the vibrating body 3 vibrates when vibration in the X direction is excited by the first piezoelectric body 2a. At the edge portion, the vibration displacement amount ξ _x can be decomposed into components in the ξ _x1 and ξ _x2 directions. Therefore, the moving body 6 that is brought into pressure contact with the ridge portion moves in the ξ _x2 direction by the ξ _x2 component of the vibration displacement ξ _x excited by the first piezoelectric body 2a.
Similarly, FIG. 3B shows a state of vibration of the ridge line portion of the vibrating body 3 when vibration in the Y direction is excited by the second piezoelectric body 2b. At the ridge, the vibration displacement amount ξ _y is ξ
It can be decomposed into components in the _y1 and ξ _y2 directions. Therefore,
The moving body 6 that is in pressure contact with the ridge portion moves in the ξ _y2 direction by the ξ _y2 component of the vibration displacement ξ _y excited by the second piezoelectric body 2 b. As described above, since the cosine direction components ξ _x2 and ξ _y2 of the vibrations that are independently excited by the first and second piezoelectric bodies 2a and 2b are components in the opposite directions, either one of the piezoelectric bodies is The moving direction of the moving body 6 can be controlled by driving, and the moving direction can be reversed by switching and inputting one AC voltage to each piezoelectric body.

Then, by either of the above driving methods,
A head 10 is provided on a moving body 6 that moves along a guide shaft 7 shown in FIG. 1, and a recording signal is taken out by a flexible P plate or the like. At this time, a high-accuracy head actuator can be obtained by feeding back the position information of the moving body 6 from the position detector 9 in order to accurately track the head 10 on the track on which the video signal is recorded. As shown as an example of the position detector 9 in FIG. 5, the polarization element 1 such as a beam splitter is used.
A semiconductor laser 13, a photo-detecting element 14 such as a photodiode, and a reflecting mirror 15 are arranged on each surface on the surface 2 as shown in the drawing, and a moving body 6 is provided with a reflecting film 16 made of an aluminum film or the like. The principle of detection is that the laser light emitted from the semiconductor laser 13 is split into two by the polarizing element 12, and one laser light 17 is reflected by the reflecting mirror 1.
The laser beam 18 is reflected by 5 and enters the photodetector 14, and the other laser beam 18 is reflected by the reflective film 15 on the moving body 6, reflected again by the polarizing element 12, and enters the photodetector 14. At this time, the position of the laser beams 17 and 18 is determined by the change in light intensity due to the difference in optical path length to the photodetector 14.

The position detecting section 9 may be any small detecting element that does not contact the moving body 6, such as an optical lever principle or an optical encoder.

As described above, according to the first embodiment of the present invention,
Since the moving body 6 moves along the guide shaft 7, the swing width is not limited in principle, the spacing angle between the tape and the head 10 becomes zero, and an ideal head actuator can be obtained.

Further, since the vibrating body 3 can be completely fixed by the supporting member 5 by providing the pressurizing mechanism section 8 on the guide shaft 7, the position of the vibrating body 3 can be determined and the driving force of the vibrating body can be applied to the moving body. Since all can be transmitted, the driving force can be increased and the driving efficiency can be improved. Because the vibrating body 3 supported by the pressure spring
In the case of the structure, since the guide shaft 7 and the moving body 6 do not absorb the vertical component of the elastic vibration excited by the piezoelectric body, the vibrating body 3 itself moves by the reaction of the vertical component of the vibration transmitted to the moving body 6. Therefore, the driving force for moving the moving body 6 is reduced, and the driving force proportional to the applied pressure cannot be obtained.

However, as shown in this embodiment, if the pressure applying mechanism 8 is provided on the guide shaft 7, the vibration cycle of the vibrating body 3 is faster than the vibration cycle of the pressure spring of the pressure applying mechanism. Therefore, the moving body 6 can be in a state of being levitated by about the vertical component of the vibration displacement, and the moving direction component of the moving body of the vibration displacement can be effectively transmitted to the moving body 6.

Further, unlike the conventional composite bimorph and parallel spring type bimorph structure, the control frequency is not limited by the mechanical resonance frequency, so that the control frequency can be made higher and more precise control can be performed. it can.

Further, since the driving principle of the moving body 6 is basically frictional driving, it is possible to obtain a head actuator which has good damping performance and is controlled with high accuracy without ringing.

By virtue of the structure in which the moving body 6 is brought into pressure contact with the ridge portion of the vibrating body 3, the restrictions on the parallelism between the moving body 6 and the vibrating body 3 and the plane accuracy are alleviated, and the cost is low and the productivity is excellent. It is possible to obtain a highly reliable head actuator.

In particular, when the vibrating body is driven by the piezoelectric body on one side, the driving circuit can be driven simply by applying an AC voltage to the piezoelectric body corresponding to the moving direction of the moving body 6, so that the driving circuit has a very simple structure. Can be

Then, even when driven by one piezoelectric body,
Compared to the case of driving by the combined vibration in the X and Y directions, the input power is almost halved, and the vibration displacement amount of about 70% is obtained, so that the driving efficiency can be improved.

Similarly, since the driving can be performed on only one side, control can be performed even if the resonance frequencies in the X and Y directions are different due to a change in the rigidity of the elastic body 1 or a change in the rigidity due to a dimensional error, and strict shape and dimensional accuracy. Etc. are not required. Therefore, a head actuator having stable characteristics can be obtained with a drive circuit having a very simple structure.

The first and second piezoelectric bodies 2a, 2b are not limited to the two planes intersecting as shown in FIG. 1, but the planes facing each other as shown in FIG. The piezoelectric body 2 is arranged so that the polarization direction is arranged as shown by the arrow.
By providing a ′ and 2b ′ and driving with the combination of the piezoelectric bodies 2a, 2a ′ and the piezoelectric bodies 2b, 2b ′, low resonance impedance and high electromechanical coupling can be obtained, and low voltage driving and load fluctuation can be achieved. The advantage is that the control circuit that follows changes in the driving frequency can be simplified.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 7 is a plan view of a head actuator according to the second embodiment of the present invention. In the figure, the leaf spring 20 provided with a position detecting element 19 such as a strain gauge is added to the moving body 6 except for the optical position detecting portion 9 of the first embodiment. As a result, the leaf spring 20 is deformed by the movement of the moving body 6,
The amount of deformation changes the resistance value of the position detecting element 19 or the like to control the position of the moving body 6. Other configurations are the same as those in the first embodiment.

As described above, according to the second embodiment of the present invention,
The same effect as in Example 1 can be obtained, while in Example 1,
It was difficult to use the expensive optical position detector 9 or read the recording signal from the head 10. However, in the present invention, the position detecting element 19 such as a strain gauge utilizing the inexpensive resistance change is used.
The position control can be performed by the above, and the wiring on the leaf spring 20 can prevent problems such as disconnection that is likely to occur in the first embodiment due to the driving of the moving body 6 in advance.

(Third Embodiment) A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 8 is a plan view of a head actuator according to the third embodiment of the present invention. In the figure, the movable body 6 is guided by the guide shaft 7 as in the first and second embodiments.
The moving mechanism 6 is sandwiched between the parallel leaf springs 21, and the pressing mechanism portion 22 is provided on the vibrating body 3 or the spring provided on the guide shaft 7 is provided on the vibrating body 3. This is a structure in which the moving body 6 is brought into pressure contact with and driven by a frictional force.

As described above, according to the third embodiment of the present invention,
By using the structure of the guide shaft 7 and the parallel leaf spring 21, in the case of the parallel leaf spring 21 alone, the moving body 6 is moved by the moment due to the pressing force at the position displaced from the center position of the moving body 6.
However, the problem that the head cannot be driven in parallel with each other and a spacing angle between the head and the magnetic tape is generated can be prevented by providing the guide shaft 7.

Further, by preventing the parallel plate spring 21 from causing a change in the direction orthogonal to the moving direction of the moving body 6 which occurs when only one guide shaft 7 is used, the magnetic tape of each head in an actuator having a multi-head structure. It is possible to prevent the deterioration of the read signal due to the inclination of the track.

Further, since the parallel plate spring 21 disperses the pressure applied by the pressurizing mechanism, the frictional resistance between the moving body 3 and the guide shaft 7 can be reduced more than in the first embodiment. Can be driven at high speed.

Further, since the position detecting element can have the same construction as that of the second embodiment, the head actuator can be made inexpensive and highly reliable.

Although the parallel spring structure is used in the third embodiment, it goes without saying that a single spring structure may be used.

(Embodiment 4) Hereinafter, Embodiment 4 of the present invention will be described with reference to the drawings.

FIG. 9 is a plan view of a head actuator according to the fourth embodiment of the present invention. This figure shows that in Example 3,
The parallel spring 24 is provided with a semi-cylindrical bent portion 23. Other configurations are similar to those of the third embodiment.

According to the fourth embodiment configured as described above,
In the structure of the parallel spring 21 of the third embodiment, there is a problem that the swing width of the moving body 6 cannot be large because it depends on the extension amount of the parallel spring, but the parallel spring 2 having the semi-cylindrical bent portion 23 is present.
By adopting the four structure, the swing width of the moving body 6 can be greatly expanded by the deformation of the bent portion 23.

(Fifth Embodiment) A fifth embodiment of the present invention will be described below with reference to the drawings.

FIG. 10 is a plan view of a head actuator according to the fifth embodiment of the present invention. This figure shows a parallel plate spring 26 provided with an R portion 25 in the supporting and fixing portion in the third embodiment. Other configurations are similar to those of the third embodiment.

According to the fifth embodiment as described above, the fourth embodiment
The rigidity of the parallel leaf spring 24 having the semi-cylindrical bent portion 23 of FIG.
By strengthening with 6, the head can be surely translated in parallel with respect to the moment described in the third embodiment.

(Sixth Embodiment) A sixth embodiment of the present invention will be described below with reference to the drawings.

FIG. 11 is a perspective view of a head actuator according to the sixth embodiment of the present invention. In the figure, the cross-sectional shape of the elastic body 1 according to the first to fifth embodiments has a triangular elastic body 27.
It is what Other configurations are the same as those in each embodiment.

Next, the piezoelectric on one side of FIGS.
The operation principle will be described by taking the case of driving by the body as an example. Basic
Specifically, it is similar to FIG. Shown in FIGS. 12 (a) and 12 (b).
, When the vibrations in the normal direction of the hypotenuses A and B are excited.
Vibration displacement ξ_AAnd ξ_BIs ξ _A1And ξ_A2Direction and ξ_B1
And ξ_B2The moving body 6 can be decomposed into_A2And ξ_B2To
Therefore, it is driven in the opposite direction.

As described above, according to the sixth embodiment of the present invention,
In a vibrating body structure having a triangular cross section, the resonance frequency of each piezoelectric body is less likely to shift than in a square vibrating body, and even if there is a shift, it can be adjusted independently.

Further, when the angles sandwiched by the hypotenuse and the base are θ ₁ and θ ₂ as shown in FIG. 11, ξ _A2 and ξ _B2 are expressed by (Equation 6) and (Equation 7),

[0058]

[Equation 6]

[0059]

[Equation 7]

At this time, for example, if the vibrator is an equilateral triangle, θ ₁ = θ ₂ = 60 degrees and ξ _A2 and ξ _B2 are about 87 of ξ _A and ξ _B.
%, A larger amplitude can be obtained compared to about 71% in the case of a square θ ₁ = θ ₂ = 45 degrees, and a head actuator with high driving efficiency can be obtained. The triangular shape of the vibrator is preferably an equilateral triangle or an isosceles triangle,
Not limited to this.

(Seventh Embodiment) A seventh embodiment of the present invention will be described below with reference to the drawings.

In the seventh embodiment, in the constructions of the first to sixth embodiments, as shown in FIG. 13, a roundness 28 is formed on at least the ridge portion of the vibrating body 3 to which the moving body 6 comes into pressure contact, thereby eliminating an edge. The other structure is the same as that of each embodiment.

According to the seventh embodiment of the present invention as described above,
The wear of the moving body 6 due to the sticking at the edge of the vibrating body 3 that occurs during driving of Examples 1 to 6 is extremely reduced, so that the life of the head actuator is significantly improved and a highly reliable actuator is obtained for a long time. Yes, the industrial benefits are immeasurable.

(Embodiment 8) An embodiment 8 of the present invention will be described below with reference to the drawings.

14 (a) and 14 (b) are sectional views of the moving body of the eighth embodiment. The figure (a) is a moving body 29 of a cantilever structure, and the figure (b) is a moving body 30 of a cantilever structure.
The other configurations are the same as those in each embodiment.

As described above, according to the eighth embodiment, since the movable bodies 29 and 30 have the function of adjusting the applied pressure, fine adjustment at the time of assembling the head actuator is very easy and the range of application can be expanded. Is. Furthermore, moving bodies 29, 3
Since it has a self-adjusting mechanism that follows the contact surface of the vibrating body 3 with the cantilevered portion and the both-sided portion of 0, it is possible to eliminate further uniform contactability and generation of noise.

[0067]

As described above, according to the present invention, the moving body is pressed against the ridge line portion of the vibrating body having a quadrangular or triangular cross section through the pressurizing mechanism portion to frictionally drive the moving body, and thereby the flat surface of the vibrating body is obtained. It is possible to realize a head actuator having stable characteristics with low cost, excellent productivity, by relaxing restrictions on accuracy and parallelism with a moving body.

Further, by driving the vibrating body at the ridge, the moving body can be driven in one direction by the cosine component of the vibration displacement excited by the AC voltage applied to one piezoelectric body, and the other piezoelectric body can be driven. Since the moving direction of the moving body can be reversed by switching and applying the AC voltage, the head actuator capable of low input driving and high driving efficiency can be easily realized with a simple configuration.

Furthermore, by moving the moving body via the guide shaft having the pressure applying mechanism, the vibrating body can be completely fixed to the fixing base via the supporting portion, so that the vibrating body is reacted by the movement of the moving body. It doesn't move. Therefore, the driving force of the moving body can be significantly improved, and the head can be positioned and driven with high accuracy.

By driving the moving body with a parallel leaf spring structure having a guide shaft having a pressing mechanism, the leaf spring corrects the inclination in the direction orthogonal to the moving direction of the moving body (head mounting direction). In addition, the relative positional relationship between the head and the magnetic tape can be maintained with extremely high accuracy by correcting the moment generated in the moving direction due to the pressing position of the moving body and the vibrating body with the guide shaft.

According to the present invention, in either method, the spacing angle is almost zero, the swing width (amplitude) is large, and the friction control between the moving body and the vibrating body causes no position control without ringing. It is possible to realize a compact and lightweight head actuator with excellent accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view of a head actuator according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a first-order free vibration distribution of a rod.

FIG. 3 is an operation explanatory diagram of the first embodiment of the present invention during composite driving.

FIG. 4 is an operation explanatory diagram of the present invention.

FIG. 5 is a block diagram of an optical position detector.

FIG. 6 is a diagram showing an arrangement example of piezoelectric bodies according to the first embodiment of the present invention.

FIG. 7 is a plan view of a head actuator according to a second embodiment of the present invention.

FIG. 8 is a plan view of a head actuator according to a third embodiment of the present invention.

FIG. 9 is a plan view of a head actuator according to a fourth embodiment of the present invention.

FIG. 10 is a perspective view of a head actuator according to a fifth embodiment of the present invention.

FIG. 11 is a perspective view of a head actuator according to a sixth embodiment of the present invention.

FIG. 12 is an operation explanatory diagram of the sixth embodiment of the present invention.

FIG. 13 is a perspective view of a vibrating body for a head actuator according to a seventh embodiment of the present invention.

FIG. 14 is a sectional view of a movable body having a doubly supported beam structure according to Example 8 of the present invention.

FIG. 15 is a perspective view of a conventional head actuator having a composite bimorph structure.

FIG. 16 is a diagram showing a driving principle of a conventional head actuator having a composite bimorph structure.

FIG. 17 is a perspective view of a conventional head actuator having a parallel spring bimorph structure.

FIG. 18 is a view showing a driving principle of a conventional parallel spring type bimorph structure head actuator.

[Explanation of symbols]

 1 quadrangular elastic body 2a, 2a 'first piezoelectric body 2b, 2b' second piezoelectric body 3 vibrating body 6 moving body 7 guide shaft 8, 22 pressurizing mechanism section 9, 19 position detector 10 head 21 parallel Spring 24 Parallel spring with bent portion 26 Parallel spring with R portion 27 Triangular elastic body 29 Moving body with cantilever structure 30 Moving body with double-supported beam structure 31 Bimorph piezoelectric body 38 Head 42 Flexible head holder

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsushi Takeda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Masanori Sumihara, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Osamu Kawasaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (11)

[Claims] 1. A rod-shaped elastic body having a quadrangular cross section,
A vibrating body in which at least one pair of intersecting elastic bodies is provided with a first piezoelectric body on one surface and a second piezoelectric body on the other surface,
A moving body that comes into contact with at least one ridge portion of the vibrating body and moves along a guide axis; a pressure mechanism section provided on the guide axis; and a signal detecting section provided on the moving body, A head actuator, comprising a position detector for optically detecting the position of the moving body. 2. A rod-shaped elastic body having a quadrangular cross section,
A vibrating body in which at least one pair of intersecting elastic bodies is provided with a first piezoelectric body on one surface and a second piezoelectric body on the other surface,
A plate provided with a moving body that comes into contact with at least one ridgeline portion of the vibrating body and moves along a guide shaft, a pressing mechanism portion provided on the guide shaft, and a position detection element fixed to the moving body. A head actuator comprising a spring and a signal detector provided on the moving body. 3. A rod-shaped elastic body having a quadrangular cross section,
A vibrating body in which at least one pair of intersecting elastic bodies is provided with a first piezoelectric body on one surface and a second piezoelectric body on the other surface,
A moving body that comes into contact with at least one ridge line portion of the vibrating body and is sandwiched by parallel springs and moves along a guide axis, a position detection unit provided on the parallel plate springs, and the moving body and the vibrating body. A head actuator comprising a pressurizing mechanism section for applying a pressure and a signal detecting section provided on the moving body. 4. A head actuator according to claim 3, wherein a pressure mechanism is provided on the guide shaft. 5. The head actuator according to claim 1, wherein the head actuator is driven by a synthetic vibration excited by application of an AC voltage to the first and second piezoelectric bodies. 6. The method according to claim 1, wherein the alternating voltage applied to the first and second piezoelectric bodies is switched for each of the piezoelectric bodies to drive the moving body by a moving direction component of each vibration. Head actuator. 7. The elastic body has a triangular cross-section, and the first and second piezoelectric bodies are provided on at least two surfaces.
The head actuator according to any one of 1. 8. The head actuator according to claim 1, wherein the ridgeline portion of the vibrating body is provided with a rounded portion at least in contact with the moving body. 9. The head actuator according to claim 3, wherein a semi-cylindrical bent portion is provided in a part of the parallel spring. 10. The head actuator according to claim 3, wherein an R portion is provided at a fixed end portion of the parallel spring. 11. The head actuator according to claim 1, wherein the movable body has a cantilevered structure or a double-supported beam structure, and the movable body has a spring property.