JPH1056788A - Linear ultrasonic motor and recording and reproducing apparatus using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a linear ultrasonic motor in which a connection member is made small and lightweight by a method wherein the connection member is formed as an integral structure which is composed of an elastic body and which does not comprise a mechanical connection and respective piezoelectric elements are attached to base parts at both ends of it while faces which are parallel to their expansion and compression direction are used as mounting faces. SOLUTION: One pair of square platelike piezoelectric elements 1, 2 which are expanded and contracted when an AC voltage is applied are connected by a connection member 3 which is composed of an elastic body. The connection member 3 is constituted of an integral structure which does not contain a mechanical connection, and base parts 3a, 3a' to which the pair of piezoelectric elements 1, 2 are attached are formed at both ends of it. The pair of piezoelectric elements 1, 2 are attached to the base parts 3a, 3a' by a bonding operation while faces which are parallel to their expansion and contraction direction are used as mounting faces. Thereby, it is not required to take into consideration the strength of the pair of piezoelectric elements 1, 2 for their mechanical connection, and the connection member 3 can be made small and lightweight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric element which generates a piezoelectric effect, which is supplied with an AC voltage signal having a frequency in an ultrasonic range, and the elastic vibration generated thereby is used as a driving source and is pressed by a vibrating body. The present invention relates to a linear ultrasonic motor for applying a driving force to a movable body using frictional force, and a recording / reproducing apparatus using the same in a lifting mechanism of a magnetic head.

[0002]

2. Description of the Related Art A conventional magnetic head lifting / lowering mechanism provided in a disk recording / reproducing apparatus for recording data by magnetic field modulation will be described with reference to FIG. FIG. 10A is a plan view of a main part of the recording / reproducing apparatus, and FIG. 10B is a side view of a main part of the recording / reproducing apparatus. The magnetic head 53 includes an arm 52
The arm 52 can be moved up and down by rotating the arm 52 in the vertical direction. The arm 52 is
The optical pickup 50 is mounted such that it can rotate in the vertical direction with respect to an angle 51 fixed to the optical pickup 50. In addition, the arm 52 is configured such that the magnetic head 53
4 so that it can be pressed with a certain range of pressure,
The angle 51 is urged by a spring 55.

The vertical movement of the arm 52 is performed by a lift lever 56 attached to a chassis 58 capable of accommodating the disk 54 so as to be vertically rotatable. That is, by moving the lift lever 56 up and down, the magnetic head 53 can be moved up and down. Also, a spring 59 is provided to urge the lift lever 56 against the chassis 58 so that the magnetic head 53 does not jump up due to vibration or drop when the magnetic head 53 is in contact with the disk 54 (recording). ing.

The vertical movement of the lift lever 56 is performed by moving the slide lever 60 in the front-rear direction. The slide lever 60 is provided to rotate the lift lever 56 by moving the lever 60 in the front-rear direction. A lift means 60a having a cam shape is formed, and a driven means 56a receiving driving of the lift means 60a is formed on the lift lever 56 side.

The slide lever 60 has a lever 6
0 is provided in the guide groove 60b, and the guide groove 60b is provided on a side surface of a lift gear 57a which is a final reduction gear of the magnetic head lifting / lowering motor 57 mounted on the chassis 58. Means (not shown) are provided. Thus, the lift gear 57a rotates with the rotation of the motor 57, and the slide lever 60 is moved back and forth.

Conventionally, as the motor 57, a DC brush motor having a high rotation speed and a low torque has been used in order to reduce the size, and the output of the motor is reduced by a speed reduction mechanism. Has become.

[0007] In recent years, ultrasonic motors using piezoelectric elements have been remarkably developed and are being put into practical use. Piezoelectric elements have the property of expanding and contracting due to the piezoelectric effect when an AC voltage signal is supplied.Conventionally, a piezoelectric element obtained by subjecting a ferroelectric substance to polarization processing is a conversion element between electric energy and mechanical energy. Has been used as.

In the ultrasonic motor, an AC voltage signal having a frequency in an ultrasonic region is supplied to the piezoelectric element by utilizing the characteristics of the piezoelectric element, and elastic vibration of expansion and contraction is generated according to the ultrasonic frequency of the AC voltage signal. Then, a point on the surface of the vibrating body to which the vibration of the piezoelectric element is transmitted, which is in contact with the movable body, that is, a mass point is drawn with an elliptical (including substantially elliptical) locus, and the movable body pressed by the vibrating body is pushed. The actuator is moved by a driving force obtained by using frictional force due to pressure.

When the movable body is in constant contact with the vibrating body and completely follows the motion of the mass point, the object does not move,
Since the frequency in the ultrasonic range is as high as 20 kHz or more, the movable body cannot follow the movement of the mass point, and comes into contact during a certain period of time in a cycle and floats during the remaining time. Therefore, since the vibrator contacts only when it is moving in a specific direction, a driving force can be applied in one direction.

As a method of generating an ultrasonic vibration of an elliptical locus, there are a traveling wave type using a traveling wave and a standing wave type using a standing wave. For the former traveling wave type, there are cases where a traveling wave itself in which a longitudinal wave and a transverse wave are combined is used, and cases where a standing wave having a spatially and temporally different phase is combined to obtain a pseudo traveling wave. is there.

The frequency of the AC voltage signal from which an output can be efficiently obtained is the resonance frequency f at which the vibration amplitude increases.
s, and the resonance frequency fs varies depending on the shape and material of the piezoelectric element. Examples of the piezoelectric element used in the ultrasonic motor include a barium titanate-based piezoelectric element.

Here, the rotary ultrasonic motor most frequently used at present is described with reference to FIG.
The rotary ultrasonic motor includes a stator 61 that generates a traveling wave when an AC voltage signal is supplied thereto, and a rotor 62 that is driven to rotate by being pressed by the stator 61 with an appropriate pressure. I have. The above-mentioned stator 61 has a piezoelectric element 63 which elastically vibrates by an AC voltage signal supplied from a driving means (not shown) to generate a traveling wave.
And an elastic body 64 adhered to the piezoelectric element 63. The rotor 62 has a lining material 65 that effectively converts the traveling wave generated by the stator 61 into rotational motion by being pressed, and a rotation that is fixed to the lining material 65 and transmits the rotational motion to a movable body (not shown). Body 66
Consists of

As shown in FIG. 12, the piezoelectric element 63 is alternately polarized in the direction of polarization every half of the wavelength λ.
a · 63b is formed at a position shifted by about 1/4 of the wavelength λ. And these two sets of electrodes 63a
2) The phase difference between each other becomes 1/4 at the same frequency in 63b
By supplying different types of AC voltage signals, the piezoelectric element 63
Generates a traveling wave that produces a rotational motion. Note that ± in the drawing indicates the polarization direction of the surface of the piezoelectric element 63.

Further, as a linear ultrasonic motor for linearly moving, there are a monorail (elliptical) type and a linear rail type depending on the shape and arrangement of a stator or a piezoelectric element.

In the former monorail type, a part of the circumference of the above-mentioned ring type piezoelectric element is elongated to have an elliptical shape, and is described in, for example, Japanese Patent Application Laid-Open No. Hei 5-3685. In the latter linear rail type, a traveling wave is generated by installing piezoelectric elements (such as a Langevin type) for oscillation and vibration absorption on both sides of a stator which is a linear rail.

However, in the above-mentioned rotary ultrasonic motors, monorail type and linear rail type linear ultrasonic motors, all types use a limited space as a maximum source due to a problem of the size of the apparatus itself. It is not suitable for applications such as doing.

That is, in the rotary ultrasonic motor shown in FIG. 11, the piezoelectric element 63 is a ring type, and the monorail type has a large portion that is not used in addition to a portion that can move linearly. In addition, the space that can be installed is limited due to the necessity of a linear stator.

In addition, in the rotary ultrasonic motor of FIG. 11, it is necessary to determine the electrode pattern as shown in FIG. 12 in the piezoelectric element 63, and it is necessary to alternately change the polarization direction in the polarization process. There is also a problem that the cost of the piezoelectric element 63 is expensive.

On the other hand, recently, a linear ultrasonic motor having a configuration as shown in FIGS. 13 and 14 has been proposed. These generate ultrasonic vibration having an elliptical trajectory by combining two thin piezoelectric elements 71 and 72 in the shape of a thin plate and expanding and contracting in the longitudinal direction. In this case, since the pair of piezoelectric elements 71 and 72 are configured to only expand and contract in one direction, the polarization directions are the same in each case, and it is not necessary to determine the electrode pattern. In addition, the thin square plate-shaped piezoelectric elements 71 and 72 are arranged in parallel with a step in the vertical direction or such that their expansion and contraction directions form an angle, and these are simply connected by a connecting member. Since it is a configuration, it is suitable for applications such as using the limited space, as well as being small in size as compared with the above-mentioned rotary ultrasonic motor, monorail type, linear rail type linear ultrasonic motor and the like. .

Hereinafter, the linear type ultrasonic motor shown in FIG. 13 will be described. The initial state of this linear type ultrasonic motor is shown in FIG. 1A, in which a pair of square plate-shaped piezoelectric elements 71 and 72 have a step parallel to the vertical direction which is the normal direction of the moving surface. It is located at the location. The piezoelectric elements 71 and 72 are connected by a connecting member 70. The connecting member 70 is connected to connecting members 74, 74 each having one end adhered to the opposing vibration surfaces 71a, 72a of the piezoelectric elements 71, 72, and connected to the other ends of the connecting members 74, 74, respectively. By converting the reciprocating motion of the 74 and 74 into an elliptical motion, a connecting table 73 for applying a driving force to a pressed movable body (not shown), and connecting the connecting bodies 74 to the connecting table 73 Connecting shaft 75.7
5 is comprised.

In the above linear type ultrasonic motor, when two kinds of AC voltage signals having the same frequency and a phase difference of π / 2 are supplied to the piezoelectric elements 71 and 72, respectively, the mass point P is The thrust is generated on the connecting table 73 by the elliptical movement, and the movable body is pressed against the connecting table 73, so that the movable body is moved in both the left and right directions indicated by the arrow B in the figure.

The driving of such a linear type ultrasonic motor will be described in detail with reference to FIGS. 13 (a) to 13 (i) and FIG. FIG. 3 shows one-cycle waveforms of two types of AC voltage signals applied to the piezoelectric elements 71 and 72. The A signal and the B signal, which are AC voltage signals, have the same frequency and the same amplitude, and have the same phase. Indicates that the B signal is advanced by π / 2 with respect to the A signal. When such two types of AC voltage signals are supplied as a signal A to the piezoelectric element 71 and a signal B to the piezoelectric element 72, first, at point b immediately after the signal supply, the signal A becomes 0.
Therefore, the B signal takes the maximum value (see FIG. 3),
As shown in (b), only the piezoelectric element 72 expands to the maximum. Therefore, from the initial state of FIG.
The interval between 1 and 72 becomes narrower, and the connecting table 73, which was horizontal in the initial state, bends upward, which is easily bent in shape. In the figure, the mass point is indicated by P.

Next, at the point c where π / 4 has elapsed, the A signal,
Since both B signals have a medium positive voltage (see FIG. 3), the piezoelectric elements 71 and 72 each have a medium extension as shown in FIG. 13C. Therefore, the piezoelectric elements 71 and 72
Are further reduced, and the connecting table 73 is further bent.
At this time, the mass point P of the connection table 73 moves toward the piezoelectric element 72 with the increase of the A signal and the decrease of the B signal.

At point d after elapse of π / 2, the voltage values of the A signal and the B signal have an inverse relationship with respect to point b (FIG. 3).
As shown in FIG. 13D, the piezoelectric element 72 does not expand and contract, and only the piezoelectric element 71 expands to the maximum. Therefore, the amount of bending of the connecting body 73 is the same as that in FIG.
The mass point P moves further toward the piezoelectric element 72 with the further increase of the A signal and the further decrease of the B signal.

At the point e where 3π / 4 has elapsed, the A signal and the B signal
Since the voltage values of the signals are balanced with opposite polarities (see FIG. 3), as shown in FIG. 13 (e), the piezoelectric element 71 is in the middle expansion and the piezoelectric element 72 is in the middle contraction. Therefore, the interval between the piezoelectric elements 71 and 72 is in the same state as the initial state in FIG. 9A, and the mass point P returns to the initial horizontal state.

At the point f where π has elapsed, the A signal becomes 0 and the B signal becomes the minimum value (see FIG. 3), and as shown in FIG. 13 (f), the piezoelectric element 71 does not expand and contract, and only the piezoelectric element 72 Shrink to maximum. Therefore, the gap between the piezoelectric elements 71 and 72 widens, and the connecting body 73 bends downward.

At point g after 5π / 4, both the A signal and the B signal are negative voltages (see FIG. 3).
As shown in FIG. 7, both the piezoelectric elements 71 and 72 have a medium compression. Therefore, the interval between the piezoelectric elements 71 and 72 becomes maximum, the connecting body 73 bends further downward, and the mass point P of the connecting base 73 decreases from the position shown in FIG. Also moves to the piezoelectric element 71 side.

At the point h where 3π / 2 has elapsed, the point f and A
Since the respective voltage implantations of the signal and the B signal are reversed (see FIG. 3), as shown in FIG. 13 (h), the piezoelectric element 72 does not expand and contract, and only the piezoelectric element 71 contracts to the maximum. Therefore, the amount of bending of the connecting body 73 is the same as that in FIG.
The mass point P moves further toward the piezoelectric element 71 with the further decrease of the A signal and the further increase of the B signal.

At the point i where 7π / 4 has elapsed, the A signal and the B signal
Since the voltage values of the signals are balanced with opposite polarities (see FIG. 3), the piezoelectric element 71 is in a medium compression state, and the piezoelectric element 72 is compressed.
Is medium elongation. Therefore, the piezoelectric elements 71 and 72
Is in a state equivalent to the initial state in FIG. 11A, and the mass point P returns to the initial horizontal state.

The point j at which π / 4 has elapsed from the point i is equivalent to the point b immediately after the voltage is supplied. That is, the linear type ultrasonic motor sets the initial state shown in FIG.
(b) → (c) → (d) → (e) →
(F)->(g)->(h)-> (i), and repeat movement of returning in the next cycle (b).
The mass point P moves elliptically.

On the other hand, the linear type ultrasonic motor shown in FIG. 14 is substantially the same in structure as the linear type ultrasonic motor shown in FIG. 13, except that the linear type ultrasonic motor shown in FIG. The first and second piezoelectric elements 7 and 72 are arranged in parallel with each other in a vertical direction with a step.
2 is arranged at a position parallel to the moving surface, and the other piezoelectric element 71 is arranged such that the expansion and contraction direction of the other piezoelectric element 72 forms an angle θ with the expansion and contraction direction of the piezoelectric element 72. for that reason,
The vertically bent portion of the connecting table 73 'of the connecting member 70'
Although the linear type ultrasonic motors have different lengths on the left and right, they have the same length. Such a linear type ultrasonic motor also has two kinds of AC voltages having the same frequency, the same amplitude, and one AC voltage signal having a phase difference of π / 2 for the piezoelectric elements 71 and 72. The supply of the signal causes the connecting table 73 'to perform an elliptical motion, generating a thrust on the connecting table 73', and the movable body pressed by the connecting table 73 'is moved in both the left and right directions indicated by the arrow B. It will be.

[0032]

However, in a configuration using a DC brush motor or the like as the magnetic head lifting / lowering motor 57 (see FIG. 10A) as in a conventional recording / reproducing apparatus, the motor is not used. Since the rotation speed is high and the torque is low, a speed reduction mechanism is required. Therefore, an increase in the number of components due to the speed reduction mechanism is unavoidable, and there is a problem that the size and thickness cannot be reduced. In addition, as the number of parts increases, the assembling work becomes complicated, and there is a problem in reliability. Further, there is a problem of noise such as noise and abnormal noise caused by gear meshing noise.

Therefore, it is conceivable to use a linear ultrasonic motor of the type shown in FIGS. 13 and 14 as a motor for lifting and lowering the magnetic head.
The linear type ultrasonic motor has the following problems.

That is, the connecting members 74 are connected to the piezoelectric element 71.
Since the mounting surface 72 is attached to the vibration surfaces 71a and 72a by bonding or the like, the normal direction of the bonding surface is the expansion / contraction direction. Therefore, the load due to the expansion and contraction of the piezoelectric elements 71 and 72 is directly applied to the bonded portion, and the bonded portion is easily peeled off, resulting in poor reliability.

Also, since the connecting members 74 are connected to the connecting base 73 by the connecting shafts 75, the connecting shafts 75, 75, the connecting members 74, 74, All 73 require a certain thickness, and there is a limit to miniaturization and weight reduction.

[0036]

According to a first aspect of the present invention, there is provided a linear ultrasonic motor comprising: a pair of piezoelectric elements which extend and contract only in one direction by a connecting member; The direction is directed to the center of the connecting member, while the contraction direction is connected to the direction away from the center of the connecting member. In a linear type ultrasonic motor that generates a sound wave vibration and applies a driving force using a frictional force to a movable body that comes into contact with the elastic portion, the connecting member is an integral component having no mechanical connection made of an elastic body. Each piezoelectric element is mounted on a base portion at both ends thereof, with a surface parallel to the expansion and contraction direction as a mounting surface.

According to the above construction, the connecting member for connecting the pair of piezoelectric elements and generating the ultrasonic vibration of the elliptical trajectory by the vibration of the two piezoelectric elements on the elastic portion is an integral member made of an elastic body without mechanical connection. Since it is a structure, a pair of piezoelectric elements are formed by a plurality of members mechanically, as in the linear ultrasonic motor of the conventional configuration (hereinafter referred to as a conventional motor of the same type) shown in FIGS. Compared with the configuration in which the connecting members are connected to each other, there is no need to consider the strength for mechanical connection, so that the connecting members can be reduced in size and weight, and as a result, the linear ultrasonic The motor itself can be reduced in size and weight.

In order to generate an ultrasonic vibration of an elliptical locus on the connecting member using the vibrations of the two piezoelectric elements, it is necessary to connect the two piezoelectric elements so as not to hinder the expansion and contraction of the two piezoelectric elements as much as possible, and to minimize the loss. Since the connecting member can be reduced in size and weight, vibration caused by expansion and contraction of the piezoelectric element can be more efficiently converted into a motor output as compared with a conventional motor of the same type.

According to the above configuration, each piezoelectric element is
Since the surface parallel to the expansion and contraction direction of the piezoelectric element is attached to the base portions formed at both ends of the connecting member as a mounting surface, the normal direction of the bonding surface is the same as the conventional motor of the same type described above. Therefore, it is possible to prevent the load due to the vibration of the piezoelectric element from being directly applied to the bonding surface, suppress the occurrence of peeling or the like, and improve the reliability.

According to a second aspect of the present invention, there is provided a linear ultrasonic motor according to the first aspect, wherein the linear ultrasonic motor has a substantially planar shape between the base portions of the connecting member, and comes into contact with the movable body to provide a driving force. And a substantially U-shaped protrusion protruding in a direction parallel to the surface direction of the movable body contact portion, and is torsionally deformed by vibration of the piezoelectric element transmitted from both base portions. And a torsionally deformable portion for generating an ultrasonic vibration of an elliptical locus is formed in the movable body contact portion.

According to the above arrangement, the torsionally deformed portion is torsionally deformed by the vibrations of the two piezoelectric elements transmitted from the both base portions, and the torsionally deformed portion is formed on the movable body contact portion by an elliptical locus. Since ultrasonic vibration is generated, for example, a connection member having a shape similar to that of a conventional motor of the same type and having base portions provided at both ends thereof can be integrated with an elastic member without mechanical connection. When it is obtained by a component, although the function described in the configuration of claim 1 can be achieved, the configuration becomes bulky in the vertical direction which is the normal direction of the movable body moving surface. It is not possible to meet the demand for thinning such as the use as a drive source of the magnetic head elevating mechanism, but by adopting such a configuration, it is possible to achieve the thinning and meet the demand for thinning.

According to a third aspect of the present invention, in the linear ultrasonic motor according to the second aspect of the present invention, the movable body contact portion is provided at the movable body contact portion of the connecting member when the distance between the pair of piezoelectric elements is reduced. It is characterized in that the movable body is formed with a warp for directing a bending direction so as to be easily bent.

According to the above configuration, the warp formed in the movable member contact portion of the connecting member makes it easier for the movable member contact portion to bend toward the movable member when the interval between the pair of piezoelectric elements is reduced. Vibration of the body contact portion is performed smoothly, and thus, the movable body can be smoothly moved.

According to a fourth aspect of the present invention, in the linear ultrasonic motor according to the second aspect of the present invention, the movable member is sandwiched between the connecting member and the movable member contact portion, and the movable member contacts the movable member contact portion by elasticity. And a pressing portion for pressing is provided integrally.

In addition to the linear type ultrasonic motor of this type, in the ultrasonic motor, the thrust generated by the ultrasonic vibration of the elliptical trajectory of the vibrating body is converted into the driving force by using the frictional force. Is indispensable means for pressing the vibration member against the ultrasonic vibrating body.

According to the above arrangement, such an indispensable pressing means is used as a pressing portion that presses the movable body with the movable body contact portion by using the elasticity of the connecting member and pressing the movable body with the movable body contact portion. Because it was formed integrally with the connecting member,
For example, compared to a case in which the pressing means is configured separately from the biasing means such as a spring, parts such as a spring, parts for fixing the same, and shaping for the same are not required,
Cost can be reduced. The adjustment of the pressing force can be easily adjusted by adjusting the gap between the movable body contact portion and the pressing portion.

According to a fifth aspect of the present invention, in the linear ultrasonic motor according to the second aspect, a projection is formed on at least one of the base portions of the connecting member, and the vibration transmission preventing member is formed on the projection. Is attached.

According to the above configuration, the projection is formed on the base portion of the connecting member, and the vibration transmission preventing member is attached to the projection. Propagation to the outside can be suppressed. For example, by mounting this linear type ultrasonic motor on a recording / reproducing device or the like, it is possible to prevent deterioration of recording / reproducing characteristics due to propagation of vibration to the recording / reproducing device or the like.

According to a sixth aspect of the present invention, in the linear ultrasonic motor according to the second aspect, the pair of piezoelectric elements includes:
It is characterized in that the piezoelectric element is arranged so that the angle formed between the mounting surface of one piezoelectric element on the base and the mounting surface of the other piezoelectric element on the base is substantially a right angle.

According to the above configuration, the pair of piezoelectric elements are
The mounting surfaces parallel to the expansion and contraction directions are arranged so that the angles formed by the mounting surfaces on the base portion are substantially right angles, that is, the angles formed by the expansion and contraction directions of both piezoelectric elements are substantially right angles.
Therefore, when alternating voltage signals having the same frequency and different phases are applied to both piezoelectric elements, the elliptical trajectory of the ultrasonic vibration generated at the movable body contact portion becomes maximum, and the amplitude of the traveling wave also becomes maximum. As a result, the moving amount of the movable body per unit time of the AC voltage signal is maximized, and the moving time per unit moving distance is minimized.

In a linear ultrasonic motor according to a seventh aspect of the present invention, in the configuration of the sixth aspect, the expansion and contraction direction of one of the pair of piezoelectric elements is parallel to the moving direction of the movable body. It is characterized by:

According to the above arrangement, when the direction of expansion and contraction of one piezoelectric element is the same as the direction of movement of the movable body, the direction of expansion and contraction of the moving body of the other piezoelectric element is perpendicular to the direction of movement of the movable body. Therefore, in addition to the operation of the structure of claim 6, the moving direction of the movable body is changed by changing the ± sign of the phase difference between the AC voltage signal applied to one piezoelectric element and the AC voltage signal applied to the other piezoelectric element. , The output difference due to the moving direction can be eliminated.

The recording / reproducing apparatus according to claim 8 of the present invention provides:
According to another aspect of the present invention, there is provided a recording / reproducing apparatus including a magnetic head elevating mechanism for elevating a magnetic head with respect to a disk on which information is recorded by magnetic field modulation. A linear ultrasonic motor described in (1) is used.

According to the above construction, the linear type ultrasonic motor according to claim 2, which has the advantages of high speed, low torque, no need for a speed reduction mechanism, high reliability, small size and thinness. Is used as a drive source of the lifting mechanism. Therefore, as compared with a configuration using a conventional DC brush motor, the number of parts can be reduced due to the elimination of a speed reduction mechanism, the assembling work can be simplified, the reliability can be improved, and gear noise and abnormal noise can be achieved. Solve the noise problem. Moreover,
Since the magnetic head can be quickly moved up and down without taking advantage of the miniaturization and thinning of the recording / reproducing device and the responsiveness which is the greatest advantage of the ultrasonic motor, recording can be started quickly in the recording / reproducing device. be able to.

According to a ninth aspect of the present invention, there is provided a recording / reproducing apparatus comprising:
A base unit, comprising the linear ultrasonic motor according to claim 7 and a piezoelectric element mounted on a side where the direction of movement of the linear ultrasonic motor and the direction of expansion and contraction thereof are substantially perpendicular to each other. Are attached to the side surface of the apparatus body by bending the drive source mounting chassis.

According to the above structure, a low-speed, high-torque, no deceleration mechanism is required, and in addition to high reliability, small size, and thinness, the moving time per unit moving distance is the shortest, and one piezoelectric element is used. In a configuration in which the moving direction of the movable body is reversed by changing the ± sign of the phase difference between the AC voltage signal applied to the other piezoelectric element and the AC voltage signal applied to the other piezoelectric element, there is no output difference due to the moving direction. 7. Since the linear ultrasonic motor according to claim 7 is used as a drive source of a lifting mechanism of the magnetic head, the magnetic head can be moved up and down more quickly than the recording / reproducing apparatus having the configuration of claim 8, and the magnetic head can be moved up and down faster. There is no difference in performance between raising and lowering the head, and mounting on the bent part of the chassis prevents the recording / reproducing device from becoming smaller and thinner. Nor is it intended to.

According to a tenth aspect of the present invention, in the recording / reproducing apparatus according to the eighth or ninth aspect, a pressing force adjusting means for adjusting a pressure for pressing the movable body against the movable body contact portion of the linear type ultrasonic motor. Is provided.

According to the above arrangement, the pressure for pressing the movable body against the movable body contact portion of the linear ultrasonic motor can be adjusted by the pressing force adjusting means. If the thickness of the mass-produced movable body varies, there is a problem that the pressing force is too strong or too weak to draw out the necessary driving force, and the magnetic head cannot be moved up and down. Although this may occur, the magnetic head can be reliably moved up and down.

[0059]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1] An embodiment of the present invention will be described below with reference to FIGS.

First, the configuration of the linear ultrasonic motor according to the present embodiment will be described with reference to FIG. FIG. 1 (a)
1 is a plan view of a linear ultrasonic motor according to the present embodiment, and FIG. 1B is a side view thereof. As shown in FIGS. 1A and 1B, this linear ultrasonic motor includes a pair of rectangular plate-shaped piezoelectric elements 1 and 2 which expand and contract in the length direction when an AC voltage signal is supplied thereto. And a connecting member 3 made of an elastic body for connecting the piezoelectric elements 1 and 2, and high-frequency AC voltage signals belonging to two types of ultrasonic regions are applied to the piezoelectric elements 1 and 2 as described later. As a result, the movable body contact portion 3b of the connecting member 3 performs an elliptical motion according to the frequency, that is, generates an ultrasonic vibration of an elliptical locus, and a thrust generated thereby is converted into a driving force by a frictional force, and an arrow is generated. A
The movable body 4 is moved in both left and right directions indicated by.

The piezoelectric elements 1 and 2 are, for example, barium titanate-based piezoelectric elements, and a connecting member 3 that connects the piezoelectric elements 1 and 2 performs an elliptical motion by expansion and contraction of the pair of piezoelectric elements 1 and 2. As described above, one piezoelectric element 2 has an arrow A
Are arranged such that the moving direction of the movable body 4 and the direction of expansion and contraction thereof are parallel to each other, and the other piezoelectric element 1 has its expansion and contraction angle θ ₁ with the expansion and contraction direction of the other piezoelectric element 2. Are located in The angle θ ₁ may be any angle at which the movable body contact portion 3b can be pushed upward when the piezoelectric element 1 is extended, and is smaller than 90 ° here.
However, as the angle θ ₁ is closer to 90 °, the movable body contact portion 3
b can be greatly increased even with the same expansion and contraction ratio of the piezoelectric elements 1 and 2.

The connecting member 3 is an integral component having no mechanical connection, and is composed of a leaf spring or the like.
At both ends of the connecting member 3, base portions 3a and 3a 'for mounting the pair of piezoelectric elements 1 and 2 are formed, and the base portions 3a and 3a' use a surface parallel to the expansion and contraction direction as a mounting surface. , Attached by gluing. As described above, since the surface parallel to the expansion and contraction direction can be attached as the attachment surface, even if the attachment is performed by adhesion, a load due to vibration does not directly apply to the adhesion surface, so that peeling or the like hardly occurs and reliability is improved. improves.

The base 3a of the connecting member 3
A movable member contact portion 3b which contacts the movable member 4 and applies a driving force to the movable member 4;
And a torsional deformation portion 3c for performing ultrasonic vibration of an elliptical locus.

The torsionally deforming portion 3 c is
b has a substantially U-shaped portion protruding in a direction parallel to the surface direction of b, and one end of the substantially U-shaped portion is bent upward and connected to one end of the movable body contact portion 3b. The other end is bent downward and is connected to the base 3a '.
With such a configuration, the movable body contact portion 3 that is torsionally deformed by the elastic vibration of the piezoelectric elements 1 and 2 transmitted from the two base portions 3a and 3a and that is connected to the torsionally deformed portion 3c.
Ultrasonic vibration of an elliptical trajectory is generated at b to generate a traveling wave.

The movable body contact portion 3b has a substantially planar shape, and has one end connected to the base 3a and the other end connected to the torsionally deformable portion 3c. Between the movable member contact portion 3b and the base portion 3a is bent at an angle theta ₁ described above, and,
Although the wall thickness is the same, it is formed narrow so that vibration can be transmitted efficiently. With such a configuration, the movable body contact portion 3b generates ultrasonic vibration of an elliptical trajectory by the deformation of the torsional deformation portion 3c due to the elastic vibration of the piezoelectric elements 1 and 2, and the normal direction of the moving surface of the movable body 4 A traveling wave having an amplitude in the up-down direction is generated to apply a driving force to the pressed movable body 4 to move the movable body 4.

Further, the movable body contact portion 3b has a warp for orienting the bending direction so as to be easily bent upward when the space between the piezoelectric elements 1 and 2 is narrowed by the elastic vibration of the piezoelectric elements 1 and 2. It is formed in a shape slightly bulging upward.

The movable body 4 is urged against the movable body contact portion 3b by a spring or the like (not shown). When ultrasonic vibration of an elliptical locus is generated in the movable body contact portion 3b, the movable body 4 is moved with the movable body contact portion 3b. The driving force is applied using the frictional force with the body 4 and the body 4 is moved.

By the way, in the above configuration, the movable body 4
Is biased to the movable body contact portion 3b by a spring or the like (not shown), but may be configured as shown in FIG. 5 in the linear ultrasonic motor of the present embodiment. .

That is, as shown in FIG. 5, the movable member 4 is sandwiched between the movable member contact portion 3b and the movable member contact portion 3b, and the pressing portion 3e which elastically presses the movable member 4 on the movable member contact portion 3b. Are provided integrally. In the linear type ultrasonic motor shown in FIG. 1, using a biasing means such as a spring,
It is necessary to press the movable body 4 against the movable body contact portion 3b, but by adopting such a configuration, parts such as springs are also required.
In addition, there is no need for a component for fixing this, and there is an excellent advantage that the cost can be reduced by reducing the number of components as compared with the configuration of FIG. The adjustment of the pressing force can be easily adjusted by adjusting the gap between the movable body contact portion 3b and the pressing portion 3e.

Next, a control system for controlling the driving of the linear ultrasonic motor having the above configuration will be described with reference to FIG. FIG. 2 is a block diagram of the control system. The control system is
Generally, a DC power supply 10 and a high-frequency AC voltage signal that is driven by the DC power supply 10 and belongs to two types of ultrasonic regions having the same amplitude, the same frequency, and having a phase difference of π / 2 are generated.・ Drive unit 1 for supplying to each of 2
It consists of 1.

The driving section 11 oscillates an oscillating section 12 that oscillates a required high-frequency AC voltage signal, and controls the phase of the AC voltage signal oscillated by the oscillating section 12 so that the piezoelectric element 1
A phase control unit 13 that adjusts the phases of two types of AC voltage signals supplied to 2 and an amplitude adjustment that adjusts the amplitudes of the two types of AC voltage signals whose phases are controlled by the phase control unit 13 to required amplitudes The oscillator 14 includes a feedback section 15 for feedback-controlling the oscillation section 12 and the amplitude adjustment sections 14a and 14b.

The phase control unit 13 converts the two AC voltage signals supplied to the piezoelectric elements 1 and 2 into one AC voltage signal as a reference and the other AC voltage signal as a reference AC voltage signal. And a reversing unit 13 for reversing the ± sign of the phase difference for reversing the linear ultrasonic motor.
b, and a phase difference detector 13c for detecting the phase difference between the voltage and the current of the two types of AC voltage signals supplied to the piezoelectric elements 1 and 2. The control system is provided with a speed detection unit 16 such as an encoder for detecting the speed of the linear ultrasonic motor.

The signal detected by the phase difference detector 13c is input to the feed hack 15 via the line L2. The feedback unit 15 inputs a control signal for maintaining the phase difference between the voltage and the current of the voltage signal within a fixed value or a fixed range to the oscillation unit 12 via the line L3 based on the detection signal. 12 controls the frequency of the AC voltage signal oscillating.

The speed detecting section 16 inputs a speed signal to the feed hack section 15 via the line L4. A speed command signal including an inversion signal is input to the feedback unit 15 via the line L1 together with the speed signal from the speed detection unit 16, and the feedback unit 15 converts the speed signal and the speed command signal. A control signal for oscillating an AC voltage signal having a predetermined speed for comparison
The signal is input to the oscillating unit 12 via the input terminal 3 Thereby, an AC voltage signal having a predetermined frequency is oscillated from the oscillation unit 12,
The signal is input to the phase difference detection unit 13c and is input to the phase difference unit 13a.

The phase difference section 13a generates an AC voltage signal whose phase is shifted by about に 対 し て with respect to the input AC voltage signal, and inputs the AC voltage signal to the inverting section 13b via the line L9. The AC voltage signal is similarly input to the inverting unit 13b via the line L5. The inverting unit 13b also receives an inversion command signal from the feedback unit 15 via a line L6. The inverting unit 13b responds to the inversion command signal by changing the phase of the AC voltage signal input via the line L9. Is changed by about 0 or ± 1 to perform the inversion drive of the linear ultrasonic motor.

The AC voltage signal input to the inverting section 13b via the line L5 is directly input to the amplitude adjusting section 14a via the line L7, and the amplitude adjusting section 14a outputs the line voltage from the feed hack section 15 to the line adjusting section 14a. The amplitude is adjusted according to the speed command signal input via L8, and is supplied to the piezoelectric element 1 of the linear ultrasonic motor.

On the other hand, the AC voltage signal input to the inverting unit 13b via the line L9 and having its phase changed by the inverting command signal is supplied to the amplitude adjusting unit 14b via the line L10.
The amplitude is adjusted by the amplitude adjuster 14b according to the speed command signal input from the feed hack unit 15 via the line L8, and is supplied to the piezoelectric element 2 of the linear ultrasonic motor.

The speed adjustment when the AC voltage signal is supplied to the two piezoelectric elements 1 and 2 is performed by adjusting one or both amplitudes of the two types of AC voltage signals supplied to the piezoelectric elements 1 and 2. There are a method of changing, a method of changing the phase difference between the two types of AC voltage signals, a method of changing the frequency of the two types of AC voltage signals, and the like, and a method of combining these three types of methods. be able to.

As described above, two types of AC voltage signals having the same frequency and one AC voltage signal having a phase difference of π / 2 are supplied to the piezoelectric elements 1 and 2 at the same frequency. As a result, ultrasonic vibration having an elliptical locus due to the traveling wave is generated in the movable body contact portion 3b, and the movable body 4 is moved.

Next, the operation of the linear ultrasonic motor having the above configuration will be described in detail with reference to FIGS. FIG.
Shows the waveforms of one cycle (2π) of two types of AC voltage signals applied to the piezoelectric elements 1 and 2. The A and B signals, which are AC voltage signals, have the same frequency and the same amplitude,
The B signal is π / 2 ahead of the A signal. When such two types of AC voltage signals are supplied to the piezoelectric element 1 as an A signal and to the piezoelectric element 2 as a B signal,
First, at point b immediately after the signal is supplied, the A signal is 0 and the B signal has the maximum value (see FIG. 3), so that the piezoelectric element 1 does not expand and contract as shown in FIG. Only 2 extends maximally. At this time, the interval between the piezoelectric elements 1 and 2 becomes narrower than the initial state in FIG. 3A, and the movable body contact portion 3b flexes upward due to the elasticity of the torsionally deformable portion 3c. In the drawing, P indicates the mass point of the movable body contact portion 3b.

At the point c where π / 4 has elapsed, both the A signal and the B signal are positive voltages (see FIG. 3). Therefore, as shown in FIG. Elongation. At this time, compared to the state shown in FIG.
2 is further reduced, the movable body contact portion 3b is further flexed upward, and the piezoelectric element 1 expands, but the amount of extension of the piezoelectric element 2 decreases. It moves to the piezoelectric element 2 side.

At point d after elapse of π / 2, the respective voltage values of the A signal and the B signal have an inverse relationship with respect to point b (FIG. 3).
4), the piezoelectric element 2 does not expand or contract, and only the piezoelectric element 1 expands to the maximum. At this time, although the amount of bending is smaller than that in the state shown in FIG. 3C, the mass point P further moves to the piezoelectric element 2 side since the piezoelectric element 1 side of the movable body contact portion 3b is lifted to the maximum.

At point e after 3π / 4, the A signal and the B signal
The voltage values of the signals are balanced with opposite polarities (see FIG. 3), and as shown in FIG. 4E, the piezoelectric element 1 has a medium expansion and the piezoelectric element 2 has a medium contraction. At this time,
The interval between the piezoelectric elements 1 and 2 is the same as that in the initial state shown in FIG. 4A, but the elastic element 3c deforms the piezoelectric element 1 and 2 to the greatest extent in the downward direction. Moving.

At the point f where π has elapsed, the A signal is 0 and the B signal has the minimum value (see FIG. 3), so that the piezoelectric element 1 does not contract and expand as shown in FIG. Only 2 contracts maximally. At this time, the shape becomes a shape elongated while bending downward, and the mass point P is opposite to that shown in FIG.
It moves to the piezoelectric element 1 side.

At point g where 5π / 4 has elapsed, both the A signal and the B signal are negative voltages (see FIG. 3), and as shown in FIG. 4 (g), both the piezoelectric elements 1 and 2 contract moderately. . At this time, the interval between the piezoelectric elements 1 and 2 becomes maximum, the movable body contact portion moves toward the piezoelectric element 1 in a state where the piezoelectric element 1 is bent downward, and the mass point P further moves toward the piezoelectric element 1.

At the point h where 3π / 2 has elapsed, the point f and A
The voltage values of the signal and the B signal are reversed (see FIG. 3), and as shown in FIG. 4H, the piezoelectric element 2 does not expand and contract, and only the piezoelectric element 1 contracts to the maximum. At this time, the piezoelectric elements 1 and 2
Moves further to the piezoelectric element 1 side than the state shown in FIG. 9G, and the mass point P further moves to the piezoelectric element 1 side.

At the point i where 7π / 4 has elapsed, the A signal and the B signal
The voltage values of the signals are balanced with opposite polarities (see FIG. 3), and as shown in FIG. 4 (i), the piezoelectric element 1 has a medium contraction and the piezoelectric element 2 has a medium expansion. At this time,
Due to the elasticity of the torsionally deformable portion 3c, the movable body contact portion 3b bends upward, and the mass point P further moves to the piezoelectric element 1 side.

The point j at which π / 4 has elapsed from the point i is equivalent to the point b immediately after the supply of the voltage, that is, the linear ultrasonic motor has the initial state shown in FIG. 2
(b) → (c) → (d) → (e) →
(F) → (g) → (h) → (i), and a repetitive motion of returning to (b) in the next cycle is again performed, during which the vertex P draws an elliptical locus.

As described above, according to the above configuration, the connecting member 3 that connects the pair of piezoelectric elements 1 and 2 and generates ultrasonic vibration of an elliptical locus on the elastic portion by the vibration of both piezoelectric elements.
Is an integral component made of an elastic body without mechanical connection. Therefore, like the linear ultrasonic motor having the conventional configuration shown in FIGS. 13 and 14 described above (hereinafter, referred to as a conventional motor of the same type), Compared to a configuration in which a pair of piezoelectric elements are connected by a connection member having a configuration in which a plurality of members are mechanically connected, there is no need to consider the strength for mechanical connection, so the size of the connection member is reduced. Therefore, the linear ultrasonic motor itself can be reduced in size and weight.
And, since the size and weight of the connecting member 3 can be reduced,
Vibration due to expansion and contraction of the piezoelectric element can be more efficiently converted to motor output as compared with a conventional motor of the same type.

According to the above configuration, each piezoelectric element 1.
2 are base portions 3a and 3 formed at both ends of the connecting member 3.
Since a surface parallel to the expansion and contraction directions of the piezoelectric elements 1 and 2 is attached to a ′ as a mounting surface, the normal direction of the bonding surface becomes the expansion and contraction direction of the piezoelectric elements as in the above-described conventional motor of the same type. Therefore, it is possible to prevent the load due to the vibration of the piezoelectric elements 1 and 2 from being directly applied to the bonding surface, suppress the occurrence of peeling and the like, and improve the reliability.

The movable member contact portion 3b which contacts the movable member 4 to apply a driving force between the base portions 3a and 3a 'of the connecting member 3, and is transmitted from the two base portions 3a and 3a'. Since the torsionally deformed portion 3c, which is torsionally deformed by the vibration of the piezoelectric elements 1 and 2 and generates an elliptical ultrasonic vibration at the movable body contact portion 3b, is formed separately from the function, the same motor output can be obtained. It can be obtained with a thin configuration, and can meet the demand for thinning.

The movable member contact portion 3b of the connecting member 3
Since the movable body contact portion 3b is formed with a warp that directs the bending direction so that the movable body contact portion 3b easily bends toward the movable body 4 when the interval between the pair of piezoelectric elements 1 and 2 is reduced, the vibration of the movable body contact portion 3b is reduced. As a result, the movable body 4 can be smoothly moved.

In this embodiment, the angle θ ₁ is formed in each of the expansion and contraction directions of the piezoelectric elements 1 and 2 so that the connecting member 3 connecting the piezoelectric elements 1 and 2 makes an elliptical motion. Although the piezoelectric elements 1 and 2 are arranged, the piezoelectric elements 1 and 2 may be arranged so as to be parallel in the vertical direction and have a step as described in the section of the related art.

Embodiment 2 Another embodiment of the present invention will be described below with reference to FIG. For the sake of convenience, members having the same functions as those described in the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

In the linear ultrasonic motor according to the first embodiment shown in FIGS. 1 and 5, the angle θ ₁ between the expansion and contraction directions of the pair of piezoelectric elements 1 and 2 is smaller than 90 °. On the other hand, in the linear ultrasonic motor according to the present embodiment, as shown in FIG. 6, a pair of piezoelectric elements 1 and 2 are arranged such that their expansion and contraction directions are substantially 90 °. It has become.

The control system for controlling the driving of the linear ultrasonic motor is the same as the control system shown in FIG. 2 of the first embodiment, and the piezoelectric element of the linear ultrasonic motor of the present embodiment is used. 1 and 2 show waveforms in FIG. 3 of the first embodiment.
The operation when the different types of AC voltage signals are applied is also the same as that shown in FIGS. 4B to 4I described above, and a detailed description thereof will be omitted.

With such a configuration, the piezoelectric element 1
-Since the expansion and contraction directions of 2 are orthogonal to each other, the movable body contact portion 3
The elliptical locus of the ultrasonic vibration generated in b becomes the maximum, and the amplitude of the traveling wave also becomes the maximum. As a result, the moving amount of the movable body 4 per unit time of the AC voltage signal is maximized, and the moving time per unit moving distance is minimized. That is, it is more efficient than the linear ultrasonic motor of the first embodiment.

In the case of the linear ultrasonic motor according to the first embodiment, since the angle θ ₁ was smaller than 90 °, the elliptical locus drawn by the mass point P of the movable body contact portion 3b was
Has an elliptical axis on the same side as the direction of expansion and contraction. Therefore, if the moving direction of the movable body 4 is reversed by changing the ± sign of the phase difference of the AC voltage signal applied to the pair of piezoelectric elements 1 and 2, the moving direction of the movable body 4 indicated by the arrow A is changed. Moving direction that makes an acute angle to the left (left side in the figure)
The performance of moving to was poor.

However, the piezoelectric element 1.
By making the expansion and contraction directions of 2 orthogonal to each other, the ellipse locus drawn by the ultrasonic vibration by the mass point of the movable body contact portion 3b has an elliptical axis in almost the vertical direction. Even with a driving method that reverses the moving direction by changing the ± sign of the phase difference between
There is almost no difference in speed or thrust depending on the traveling direction.

[Embodiment 3] Another embodiment of the present invention will be described below with reference to FIGS. 7 and 8. For convenience of explanation, members having the same functions as the members described in the above embodiment are given the same reference numerals, and explanations thereof will be omitted.

This embodiment exemplifies a case in which the linear ultrasonic motor according to the present invention is used as a magnetic head elevating motor for elevating a magnetic head in a disk recording / reproducing apparatus for recording data by magnetic field modulation.

The lifting mechanism of the magnetic head in the recording / reproducing apparatus of this embodiment will be described with reference to FIG. FIG. 7A is a plan view of a main part of the recording / reproducing apparatus, and FIG. 7B is a side view of a main part of the recording / reproducing apparatus. The magnetic head 23 is attached to the arm 22 and the arm 2
2 can be moved up and down by a rotational movement in the vertical direction. The arm 22 is attached so that the arm 22 can rotate vertically with respect to the angle 21 fixed to the optical pickup 20. The arm 22 is provided with the magnetic head 2.
The spring 3 is urged against the angle 21 so that the disc 3 can be pressed against the disc 24 with a certain range of pressure.

The up-down rotation of the arm 22 is performed by a lift lever 26 attached to the chassis 28 capable of storing the disk 24 so as to be rotatable up-down. That is, by moving the lift lever 26 up and down, the magnetic head 23 can be moved up and down. Further, a spring 29 is provided to urge the lift lever 26 against the chassis 28 so that the magnetic head 23 does not jump up due to vibration or drop when the magnetic head 23 is in contact with the disk 24 (recording). ing.

The vertical rotation of the lift lever 26 is performed by moving the slide lever 30 in the front-rear direction, and the slide lever 30 is rotated by the movement of the lever 30 in the front-rear direction. A lifting means 30a having a cam shape is formed, and a driven means 26a for receiving the drive of the lifting means 30a is formed on the lift lever 26 side.

The slide lever 3 is mounted on the chassis 28.
A linear ultrasonic motor 40 is attached so that 0 can be regarded as a movable body and the lever 30 can be moved in the front-rear direction.

The linear ultrasonic motor 40 is a linear ultrasonic motor of the type shown in FIG. 6 described in the second embodiment. Therefore, the piezoelectric element 1 is attached to the main surface of the chassis 28. The plane is substantially perpendicular. Here, a base portion 3a on which the piezoelectric element 1 is mounted is attached to a side surface portion of the chassis 28 that is formed by bending, so that the base portion 3a does not become bulky in the vertical direction, and is reduced in size and thickness. It is trying to make it.

FIG. 8 is an enlarged view of a portion where the linear ultrasonic motor 40 is mounted. Each of the base portions 3a and 3a 'of the connecting member 3 in the linear ultrasonic motor 40 is formed with two convex portions 3f, and each of these convex portions 3f is formed.
, A vibration isolating rubber 41, which is a vibration transmission preventing member, is attached. Attachment of the base portion 3a to the chassis 28
Mounting brackets 42a, 42 for pressing and fixing the vibration isolating rubbers 41 attached to the base 3a from the outer peripheral side.
a, and the mounting of the base 3a '
Mounting brackets 42b and 42 for pressing and fixing the vibration isolating rubbers 41 attached to the base 3a 'from the outer peripheral side
b. By mounting via the vibration isolating rubber 41, the vibration of the piezoelectric elements 1 and 2 is prevented from being transmitted to the chassis 28 via the bases 3a and 3a '.

The connecting member 3 of the linear type ultrasonic motor 40 is provided with the above-mentioned pressing portion 3e. The slide lever 30 is sandwiched between the moving member contact portion 3b and the moving member by elastic force. The slide lever 30 is pressed toward the contact portion 3b. Therefore, in this case, the dimension between the movable body contact portion 3b and the pressing portion 3e is
Considering the thickness of the slide lever 30 and the elastic force of the pressing portion 3e, the slide lever 30 is designed to be driven without any problem.

The linear type ultrasonic motor 40
Are driven by a control system similar to that of FIG. 2 described in the first embodiment.

In the recording / reproducing apparatus having the above configuration,
When the A signal shown in FIG. 3 is supplied to the piezoelectric element 1 of the linear ultrasonic motor 40 and the B signal is supplied to the piezoelectric element 2, the phase of the B signal advances by π / 2 with respect to the A signal in FIG. Therefore, the mass point of the movable body contact portion 3b rotates clockwise, the slide lever 30 is moved forward, the lift lever 26 rotates downward, and the magnetic head 23 rotates downward. Get down while.

Further, assuming that the phase of the B signal is delayed by π / 2 with respect to the A signal so that the phase difference relationship between the A signal and the B signal in FIG. Is rotated counterclockwise, the slide lever 30 is moved backward, the lift lever 26 rotates upward, and the magnetic head 23 rises while rotating upward.

As described above, according to the above configuration, a low-speed, high-torque, no deceleration mechanism is required, high reliability, small size, low profile, shortest moving time per unit moving distance,
Also, by changing the ± sign of the phase difference between the two types of AC voltage signals supplied to the pair of piezoelectric elements 1 and 2, even if the moving direction of the movable body is reversed, there is almost no output difference due to the moving direction. The linear type ultrasonic motor 40 is used as a drive source of an elevating mechanism of the magnetic head 23.

Therefore, as compared with a conventional configuration using a DC brush motor, the number of parts can be reduced due to the elimination of a speed reduction mechanism, the assembly work can be simplified, the reliability can be improved, and the gear noise and noise can be reduced. The noise problem due to abnormal noise can be solved. Moreover, since the magnetic head can be quickly moved up and down by utilizing the responsiveness which is the greatest advantage of the ultrasonic motor, the recording and reproducing apparatus can be started and stopped without preventing the recording and reproducing apparatus from being reduced in size and thickness. Can be done quickly.

When the expansion and contraction directions of the pair of piezoelectric elements 1 and 2 are substantially perpendicular to each other as in the case of the linear ultrasonic motor 40, the above-mentioned advantages are obtained. It may be bulky in the vertical direction,
Since the mounting is performed by using the side surface of the chassis 28 by bending, the size and thickness can be reduced.

In order to move the magnetic head 23 up and down,
Since the slide lever 30 only has to be reliably moved back and forth, the drive control of the linear ultrasonic motor does not require complicated control such as speed control, and the drive circuit itself that constitutes the control system can be simplified, thereby reducing costs. Becomes possible.

Incidentally, a composite vibration type is disclosed in Japanese Unexamined Patent Publication No. 7-177.
No. 767 discloses a linear ultrasonic motor that moves a moving body by a combined vibration of a bending vibration and a longitudinal vibration. In the linear ultrasonic motor described in the publication, an elastic body is used. The shape extends in the vertical direction perpendicular to the moving direction of the movable body. Therefore, it is disadvantageous for a driving source of the magnetic head lifting / lowering mechanism of the recording / reproducing apparatus as in the present embodiment, which requires a thin structure.

[Embodiment 4] Another embodiment of the present invention will be described below with reference to FIG. For convenience of explanation, members having the same functions as the members described in the above embodiment are given the same reference numerals, and explanations thereof will be omitted.

As shown in FIG. 9, the recording / reproducing apparatus according to the present embodiment has a pressing force adjusting mechanism capable of adjusting the pressing force for pressing the slide lever 30 to the movable body contact portion 3b within a certain range. Mechanism (pressing force adjusting means) is provided,
This is different from the recording / reproducing apparatus of the third embodiment. Therefore, only the configuration of the pressing force adjusting mechanism will be described below. FIG. 9A is a plan view of a main part of the recording / reproducing apparatus, and FIG. 9B is a side view of a main part of the recording / reproducing apparatus. As described in the third embodiment, when the magnetic head 23 is moved up and down, the slide lever 30 is moved back and forth by the elliptical motion of the movable body contact portion 3b in the linear ultrasonic motor 40, and the movable body contact portion 3b is moved. In order to transmit the generated thrust to the slide lever 30 via the frictional force,
It is important that the pressing force for pressing the slide lever 30 against the movable body contact portion 3b be within a necessary and fixed range.

That is, if the pressing force is small, the necessary thrust cannot be obtained, and the slide lever 30 cannot be moved. Conversely, if the pressing force is large, the expansion and contraction of the piezoelectric elements 1 and 2 is hindered, and the necessary thrust is not generated, so that the slide lever 30 cannot move.

In the recording / reproducing apparatus according to the third embodiment, the pressing portion 3e is integrated with the connecting member 3 of the linear ultrasonic motor 40 so as to reliably press the movement of the linear ultrasonic motor 40. The pressing force is adjusted by adjusting the distance between the movable body contact portion 3b and the pressing portion 3e. However, in the case of such a configuration, the pressing force is adjusted only by the dimensional accuracy of the holding portion, so that the variation in the pressing force in actual mass production increases.

Therefore, in the recording / reproducing apparatus of the present embodiment, the distance between the pressing portion 3e 'of the linear ultrasonic motor 40 and the movable body contact portion 3b is set so that a slight gap is formed even after the slide lever 30 is inserted. And a pressing adjustment member 34 for applying a downward pressure to the pressing portion 3e 'is provided.

The pressing adjustment member 34 has a pressing portion 34b for applying a downward pressure to the pressing portion 3e ', and a pressing portion 34b is screwed into an adjusting screw 35 described later so that the pressing portion 34b is connected to the pressing portion 3e'. And a pressure-receiving portion 34a which is pressed down so as to apply pressure thereto. The pressing adjustment member 34 is fixed to the fixing table 33 with elasticity without hindering the movement of the piezoelectric elements 1 and 2.

The fixed base 33 is formed of a material having a vibration damping property such as a molding material so that the elastic vibration transmitted when the pressing adjustment member 34 comes into contact with the linear ultrasonic motor 40 is not transmitted to the chassis 28. , Pressure adjusting member 3
4 is attached to the chassis 28, and the adjusting screw 35 adjusts the pressing force by pushing down the pressure-receiving portion 34a. Then, the adjusting screw 35 is fixed to the fixing table 33 by the reaction force of the pressure-receiving portion 34a. I have. That is, the above-mentioned pressing force adjusting mechanism includes the pressure adjusting member 34, the fixing base 33, the adjusting screw 3
5 and a pressing portion 3e '.

Here, the adjustment of the pressing force to the slide lever 30 uses a method of adjusting the pressing force by a change in fanatic frequency when an AC voltage signal is supplied to the piezoelectric elements 1 and 2 so that the resonance frequency is within a certain range. The pressing force is adjusted by the adjusting screw 35 so that

By providing such a pressure adjusting member 34, the pressing force at which the slide lever 30 can be reliably moved can be adjusted while satisfying the demand for thinning, and the manufacturing can be performed under a mass production system. Reliability can be improved.

[0126]

As described above, in the linear ultrasonic motor according to the first aspect of the present invention, the connecting member is an integral component made of an elastic body without mechanical connection, and is provided on the base portions at both ends thereof. ,
In this configuration, each piezoelectric element is mounted with a surface parallel to the expansion and contraction direction as a mounting surface.

As a result, compared to a conventional motor of the same type, in which a pair of piezoelectric elements are connected by a connecting member having a structure in which a plurality of members are mechanically connected, mechanical coupling is achieved. Since it is not necessary to consider the strength of the linear ultrasonic motor, the size and weight of the connecting member can be reduced, and the size and weight of the linear ultrasonic motor itself can be reduced.

Further, since the connecting member can be reduced in size and weight, vibration caused by expansion and contraction of the piezoelectric element can be more efficiently converted into a motor output as compared with a conventional motor of the same type.

Further, since the piezoelectric element is mounted with the surface parallel to the direction of extension as a mounting surface, it is possible to prevent the load due to the vibration of the piezoelectric element from being directly applied to the bonding surface, to suppress the occurrence of peeling and the like, and to improve the reliability. The effect that it can improve is produced.

According to a second aspect of the present invention, in the linear ultrasonic motor according to the first aspect, a substantially planar shape is formed between the base portions of the connecting members, and the driving force is generated by contacting the movable member. And a substantially U-shaped protrusion protruding in a direction parallel to the surface direction of the movable body contact portion, and is torsionally deformed by vibration of the piezoelectric element transmitted from both base portions. And a torsionally deforming portion for generating an ultrasonic vibration of an elliptical locus is formed in the movable body contact portion.

Accordingly, the present invention includes
With the same shape as the connection member of the same type of conventional motor,
Compared to a configuration in which a connecting member in the shape of a base provided at both ends is obtained as an integrated component without mechanical connection made of an elastic body,
It is possible to achieve a reduction in thickness, and it is possible to meet the demand for a reduction in thickness required for use in a recording / reproducing apparatus.

According to a third aspect of the present invention, in the linear ultrasonic motor according to the second aspect of the present invention, the movable body contact portion is provided at the movable body contact portion of the connecting member when the distance between the pair of piezoelectric elements is reduced. This is a configuration in which a warp is formed on the movable body side so as to easily bend the bending direction.

As a result, the vibration of the movable body contact portion is performed smoothly, so that in addition to the effect of the configuration of the second aspect, the movable body can be smoothly moved.

According to a fourth aspect of the present invention, in the linear ultrasonic motor according to the second aspect, the movable body is sandwiched between the connecting member and the movable body contact portion, and the movable body is contacted with the movable body contact portion by elasticity. This is a configuration in which a pressing portion for pressing is integrally provided.

Accordingly, in addition to the effect of the structure of claim 2, for example, compared with the case where the pressing means is formed separately from the urging means such as a spring, the parts such as the spring are also used for fixing the same. This eliminates the need for parts and the processing of shapes for the parts, and thus has the effect of reducing costs.

According to a fifth aspect of the present invention, in the linear ultrasonic motor according to the second aspect of the present invention, a projection is formed on at least one of the base portions of the connecting member, and the vibration transmission preventing member is formed on the projection. Is attached.

Thus, in addition to the effect of the second aspect, the propagation of the vibration of the piezoelectric element to the outside can be suppressed. For example, this linear type ultrasonic motor is mounted on a recording / reproducing apparatus or the like. In this case, it is possible to prevent the recording / reproducing characteristics from being deteriorated due to the propagation of vibration to the recording / reproducing device.

According to a sixth aspect of the present invention, in the linear ultrasonic motor according to the second aspect, the pair of piezoelectric elements includes:
The configuration is such that the angle formed between the mounting surface of one piezoelectric element on the base and the mounting surface of the other piezoelectric element on the base is substantially perpendicular.

Thus, when an AC voltage signal having the same frequency and a different phase is applied to both piezoelectric elements, the elliptical trajectory of the ultrasonic vibration generated at the contact portion of the movable body becomes maximum, so that the amplitude of the traveling wave is also reduced. Will be the largest. As a result, in addition to the effect of the configuration of claim 2, the moving amount of the movable body per unit time of the AC voltage signal is the largest, and the moving time per unit moving distance is the shortest, so that the movable body can be moved with high efficiency. This has the effect.

According to a seventh aspect of the present invention, in the linear ultrasonic motor according to the sixth aspect, a direction in which one of the pair of piezoelectric elements expands and contracts is parallel to a moving direction of the movable body. Configuration.

Accordingly, in addition to the effect of the configuration of claim 6, the phase difference of the AC voltage signal applied to one piezoelectric element with respect to the AC voltage signal applied to the other piezoelectric element is ± 10%.
In a configuration in which the moving direction of the movable body is reversed by changing the sign, there is an effect that an output difference due to the moving direction can be eliminated.

The recording / reproducing apparatus according to claim 8 of the present invention provides:
As described above, in a recording / reproducing apparatus including a magnetic head lifting mechanism for raising and lowering a magnetic head with respect to a disk on which information is recorded by magnetic field modulation, a driving source of the magnetic head lifting mechanism is a linear drive according to claim 2. This is a configuration using a type ultrasonic motor.

Thus, the linear ultrasonic motor according to the second aspect of the present invention has the advantages of low speed, high torque, no need for a speed reduction mechanism, high reliability, small size, and thinness. Since it is used as a drive source, the number of parts can be reduced, the assembly work can be simplified, and the reliability can be improved, as compared with a conventional configuration using a DC brushed motor or the like, because there is no need for a speed reduction mechanism. Noise problems due to gear noise and abnormal noise can be solved. Moreover, since the magnetic head can be quickly moved up and down by utilizing the responsiveness which is the greatest advantage of the ultrasonic motor, the recording and reproducing apparatus can be started and stopped without preventing the recording and reproducing apparatus from being reduced in size and thickness. There is also an effect that it can be performed quickly.

The recording / reproducing apparatus according to the ninth aspect of the present invention provides:
A base unit, comprising the linear ultrasonic motor according to claim 7 and a piezoelectric element mounted on a side where the direction of movement of the linear ultrasonic motor and the direction of expansion and contraction thereof are substantially perpendicular to each other. Is attached to the side surface of the apparatus body by bending the drive source mounting chassis.

Accordingly, a low-speed, high-torque, no deceleration mechanism is required, high reliability, small size, and thinness are obtained, and the moving time per unit moving distance is the shortest. 8. The linear device according to claim 7, wherein the moving direction of the movable body is reversed by changing the ± sign of the phase difference of the AC voltage signal applied to the other piezoelectric element with respect to the voltage signal, so that there is no output difference due to the moving direction. Since the type ultrasonic motor is used as a drive source of the elevating mechanism of the magnetic head, the elevating and lowering of the magnetic head can be performed more quickly than the recording / reproducing apparatus having the structure of claim 8, and the magnetic head can be raised. It is said that there is no difference in performance between the case and the case where the recording / reproducing apparatus is lowered, and that the recording / reproducing apparatus can be reduced in size and thickness by being attached to the bent portion of the chassis. An effect.

According to a tenth aspect of the present invention, in the recording / reproducing apparatus according to the eighth or ninth aspect, a pressing force adjusting means for adjusting a pressure for pressing the movable body against the movable body contact portion of the linear type ultrasonic motor. Is provided.

Thus, the pressure for pressing the movable body against the movable body contact portion of the linear ultrasonic motor can be adjusted by the pressing force adjusting means. Even when the magnetic head is manufactured under a mass production system, the magnetic head can be reliably moved up and down, and the reliability of the device can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an example of a linear ultrasonic motor according to the present invention.

FIG. 2 is a block diagram of a control system that controls driving of a linear ultrasonic motor.

FIG. 3 is a waveform diagram of two types of AC voltage signals supplied to a piezoelectric vibrator.

FIG. 4 is an operation explanatory diagram for explaining an operation of the linear ultrasonic motor of FIG. 1;

FIG. 5 is a configuration diagram showing another example of the linear ultrasonic motor of the present invention.

FIG. 6 is a configuration diagram showing another example of the linear type ultrasonic motor of the present invention.

FIG. 7 is a configuration diagram illustrating an example of a recording / reproducing apparatus according to the present invention.

FIG. 8 is an enlarged view of a main part of the recording / reproducing apparatus of FIG.

FIG. 9 is a configuration diagram showing another example of the recording / reproducing device of the present invention.

FIG. 10 is a configuration diagram illustrating an example of a conventional recording / reproducing apparatus.

FIG. 11 is a perspective view showing a configuration of a conventional rotary ultrasonic motor.

FIG. 12 is an explanatory diagram showing a polarization direction and an electrode pattern of a piezoelectric element in the ultrasonic motor of FIG.

FIG. 13 is an explanatory diagram showing the configuration and operation of a conventional linear ultrasonic motor.

FIG. 14 is a configuration diagram of another conventional linear ultrasonic motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric element 2 Piezoelectric element 3 Connecting member 3a Base part 3a 'Base part 3b Movable body contact part 3c Torsion deformation part 3e Pressing part 3e' Pressing part 4 Movable body 23 Magnetic head 30 Slide lever (movable body) 33 Fixed Table 34 Press adjustment member 35 Adjustment screw

Claims (10)

[Claims] A pair of piezoelectric elements, which expand and contract in only one direction, are connected to each other by a connecting member such that an extending direction is a direction toward a center of the connecting member, and a contracting direction is a direction away from the center of the connecting member. And a linear type supersonic generator that generates an ultrasonic vibration of an elliptical locus on the surface of the elastic portion of the connecting member by the vibration of the two piezoelectric elements, and applies a driving force to the movable body that contacts the elastic portion using a frictional force. In the acoustic wave motor, the connection member is an integrated member made of an elastic body without mechanical connection, and each piezoelectric element is attached to base portions at both ends thereof with a surface parallel to the expansion and contraction direction as an attachment surface. A linear ultrasonic motor characterized by the above-mentioned. 2. A movable body contact portion which is substantially planar between the base portions of the connecting member and contacts the movable body to apply a driving force, and a plane parallel to a plane direction of the movable body contact portion. And a torsionally deforming portion which is formed in a substantially U-shape protruding in the direction and is torsionally deformed by the vibration of the piezoelectric element transmitted from both base portions to generate an ultrasonic vibration of an elliptical locus at the movable body contact portion. 2. The linear ultrasonic motor according to claim 1, wherein the linear ultrasonic motor is formed. 3. The movable member contact portion of the connecting member is formed with a warp for directing a bending direction so that the movable member contact portion easily bends toward the movable member when the interval between the pair of piezoelectric elements is reduced. The linear ultrasonic motor according to claim 2, wherein: 4. The connecting member is provided with a pressing portion for sandwiching the movable body with the movable body contact portion and pressing the movable body against the movable body contact portion by elasticity. 2. The linear ultrasonic motor according to 2. 5. A linear ultrasonic motor according to claim 2, wherein a projection is formed on at least one base of said connecting member, and a vibration transmission preventing member is attached to said projection. . 6. A pair of piezoelectric elements are arranged such that an angle formed between a mounting surface of one piezoelectric element on a base portion and a mounting surface of the other piezoelectric element on a base portion is substantially a right angle. 3. The linear ultrasonic motor according to claim 2, wherein: 7. The linear ultrasonic motor according to claim 6, wherein the direction of expansion and contraction of one of the pair of piezoelectric elements is parallel to the direction of movement of the movable body. 8. A recording / reproducing apparatus having a magnetic head elevating mechanism for elevating a magnetic head with respect to a disk on which information is recorded by magnetic field modulation, wherein a linear ultrasonic motor is used as a drive source of the magnetic head elevating mechanism. The linear ultrasonic motor includes a pair of piezoelectric elements that expand and contract only in one direction by a connecting member, and the extending direction is directed to the center of the connecting member, while the contracting direction is from the center of the connecting member. Connect so that they are in the direction away from each other,
An ultrasonic vibration of an elliptical locus is generated by the vibration of both piezoelectric elements on the surface of the elastic portion of the connecting member, and a driving force is applied to the movable body that contacts the elastic portion by using a frictional force. It is an integral component without mechanical connection consisting of an elastic body,
Each piezoelectric element is mounted on a base portion at both ends thereof with a surface parallel to the direction of expansion and contraction as a mounting surface, and a substantially planar shape is formed between the base portions, and the driving force is generated by contacting the movable body. And a substantially U-shaped projection protruding in a direction parallel to a surface direction of the movable body contact portion, and is torsionally deformed by vibration of the piezoelectric element transmitted from both base portions. A torsionally deformable portion for generating an ultrasonic vibration of an elliptical trajectory at the movable body contact portion. 9. The linear ultrasonic motor according to claim 1, wherein an angle formed between a mounting surface of the one piezoelectric element on the base portion and a mounting surface of the other piezoelectric element on the base portion is substantially a right angle.
The base on which the piezoelectric element on the side where the expansion and contraction direction of one of the piezoelectric elements is parallel to the moving direction of the movable body and the moving direction and the expansion and contraction direction are substantially perpendicular to each other is used for mounting the drive source of the apparatus body. 9. The recording / reproducing apparatus according to claim 8, wherein the recording / reproducing apparatus is attached to a side surface of the chassis by bending the chassis. 10. The recording / reproducing apparatus according to claim 8, wherein a pressing force adjusting means for adjusting a pressure for pressing the movable body is provided at a movable body contact portion of the linear type ultrasonic motor. .