JP5277467B2 - Ultrasonic actuator and magnetic recording apparatus - Google Patents

Description

  The present invention relates to an ultrasonic actuator and a magnetic recording apparatus, and more particularly to an ultrasonic actuator and a magnetic recording apparatus that generate relative movement by pressing a moving body against a vibrating body.

  In the past, attempts have been made to use ultrasonic actuators in various mobile devices. An ultrasonic actuator is generally composed of a vibrating body including a piezoelectric element that is an electro-mechanical energy conversion element, a driven body (moving body) that contacts the vibrating body in a pressurized state, and the like. The ultrasonic actuator is brought into pressure contact with the vibrating body by inputting a drive signal to the vibrating body, causing the vibrating body to expand and contract, and causing part of the vibrating body to perform elliptical vibration (hereinafter, including circular vibration). A relative motion is generated between the driven body and the driven body by a frictional force.

  Ultrasonic actuators are used as driving devices for electronic devices such as electronic cameras because they are small and excellent in quietness, and can perform high-speed and high-precision positioning control. In recent years, use as a magnetic head drive device of a magnetic recording device (HDD) has been studied, and its application is further expanding.

  Incidentally, the HDD is required to have extremely high durability, for example, durability performance of energization for 20,000 hours or more. Also, the HDD disk room is required to have a very high level of cleanliness. For this reason, when an ultrasonic actuator is used in such an HDD, it is necessary to improve durability and to strictly control the scattering of abrasion powder generated from the sliding portion to the outside of the actuator unit.

As a method to meet such demands, wear is suppressed and durability is increased by interposing a traction oil as a lubricant between the contact portion of the vibrating body and the sliding surface of the moving body that is in contact with the contact portion. Furthermore, a method for preventing leakage of traction oil by dip-coating a fluorine-based water / oil repellent agent on a portion other than the sliding portion is known (for example, Patent Document 1). A method of applying grease to the sliding surface has been conventionally known.
JP 2004-32985 A

  However, the method disclosed in Patent Document 1 has the following problems 1 to 3.

  1. After the vibrating body and the moving body (rotor) are immersed in the fluorine agent, the sliding portion needs to be polished and cleaned in order to remove the fluorine agent on the sliding surface, resulting in a complicated process.

  2. The oil repellent has an action of repelling the lubricating oil, but if the amount of the lubricating oil is large, there is a risk of leakage, so it is necessary to strictly control the coating amount (film thickness).

  3. The traction oil is volatile, and the oil is supplied by bringing a cloth-like member such as a chamois impregnated with the traction oil into contact with the rotor. In such a configuration, since the cloth-like member is always in contact with the rotor, a driving load, particularly a driving load in the case of bidirectional driving, increases. When used in an HDD, the volatile component of the oil itself causes a magnetic head failure.

  Further, in the method using grease as the lubricant, the grease is semi-solid in a normal state, and therefore, the retainability is higher than that of oil, and it is difficult to leak. However, since the viscosity is high, the vibration of the vibrating body is attenuated and the output may be reduced. Also, when reciprocating at a very short cycle, such as when driving a magnetic head in an HDD, the oil film on the sliding surface is scraped off by the contact portion of the vibrating body, and the sliding area of the contact surface of the rotor Pushed out. In the case of oil with low viscosity, the permeation speed is fast, so that it returns to the sliding surface earlier than the reciprocating operation, and an appropriate oil film is always maintained. Since the penetration speed is slow, there is a problem that the oil runs out and wears.

  The present invention has been made in view of the above problems, and an ultrasonic actuator capable of obtaining high durability performance while maintaining excellent driving performance without increasing complexity and cost of the apparatus, and magnetic An object is to provide a recording apparatus.

The above object is achieved by the invention described in any one of 1 to 8 below.

1. A vibrating body having a contact portion for performing predetermined vibration;
The contact portion is in pressure contact has a contacted portion which includes a sliding region that slides relative to the contact portion by the vibration of the contact portion, by Ri before Symbol vibrator on the slide An ultrasonic actuator comprising a moving body that generates relative movement with respect to
The front Symbol contacted portion, a lubricant is applied blended with a gelling agent,
The lubricant applied to the contacted portion is pushed away from the sliding region by the vibration in a state where the contacting portion is in pressure contact with the sliding region, and the gel is placed outside the sliding region. The bulge part of the lubricated lubricant is formed,
Wherein the sliding region, the contact portion is liquefied by vibrating in contact pressure, or ultrasonic actuator the lubricant, characterized in Rukoto fastened by the raised part viscosity is lowered.

2. The vibrator has a plurality of the abutting portions directed outward from the center,
The moving body has a cylindrical shape that circumscribes the plurality of contact portions,
A groove is formed in the contacted portion along the moving direction of the moving body,
The ultrasonic actuator according to claim 1, wherein the contact portion vibrates in a state of being fitted in the groove.
3 . The lubricant in the vicinity of the contact portion is
3. The ultrasonic actuator according to 1 or 2 , wherein the ultrasonic vibration by the abutting portion is applied and the liquefaction or viscosity is lowered and gelation occurs during the suspension of the ultrasonic vibration.

4 . 4. The ultrasonic actuator according to 3 above, wherein the lubricant is a mineral or synthetic base oil blended with a wax or a higher fatty acid.

5 . 5. The ultrasonic actuator according to 4 , wherein the lubricant base oil is traction oil.

6 . 6. The ultrasonic actuator according to 5 , wherein an extreme pressure agent is blended in the lubricant as an additive.

7 . A plurality of recesses or holes for storing the lubricant are formed in the contact portion of the vibrating body and the contacted portion of the moving body or any one of the contact surfaces. The ultrasonic actuator according to any one of 6 .

8 . A recording medium for recording information;
A magnetic head for reading and writing the information on the recording medium;
An arm that supports the magnetic head to be movable relative to the recording medium;
The ultrasonic actuator according to any one of 1 to 7 above,
The magnetic recording apparatus according to claim 1, wherein the arm is fixed to the moving body provided in the ultrasonic actuator.

  According to the present invention, the lubricant containing the gelling agent is interposed between the contact portion of the vibrating body and the contacted portion of the moving body. In other words, by applying a gel-like lubricant to the sliding surface (contacted portion) of the moving body that comes in contact with and slides on the vibrating body, good wear resistance can be obtained and high durability performance can be obtained. Can be obtained. Moreover, since wear powder and a lubricant can be reliably held and leakage can be prevented, high cleanliness can be obtained.

  Further, by using the ultrasonic actuator having such a configuration for driving the head of the magnetic recording apparatus, high durability performance can be obtained while maintaining excellent driving performance.

1 is an overall configuration diagram of an ultrasonic actuator according to an embodiment of the present invention. It is a figure which shows the fixing method of a vibrating body. It is a figure which shows the structure of a vibrating body. It is a schematic diagram which shows the mode of a deformation | transformation in the natural mode of a vibrating body. It is a schematic diagram which shows the mode of a change of the elliptical locus with respect to the phase difference of a drive signal. 1 is an overall configuration diagram showing an outline of a magnetic recording apparatus according to an embodiment of the present invention. It is a schematic diagram which shows the aspect of the gel-like lubricant after the chip | tip member of a vibrating body passes. It is a figure which shows the structure by another example of the sliding surface of a moving body.

Explanation of symbols

1A Magnetic recording device (HDD)
DESCRIPTION OF SYMBOLS 1 Case 2 Disk 3 Head 4 Arm 5 Ultrasonic actuator 10 Vibration body 10a Through-hole 101 Piezoelectric member 101a A phase electrode 101b B phase electrode 101c Common electrode 103 Chip member 20 Rotor (moving body)
20a V-shaped groove 20b Sliding surface 201 Gel lubricant 30 FPC (flexible printed wiring board)
40 Fixing member 401 Fixing pin 403 Screw 405 Adhesive

  Embodiments of an ultrasonic actuator and a magnetic recording apparatus according to the present invention will be described below with reference to the drawings. In addition, although this invention is demonstrated based on embodiment of illustration, this invention is not limited to this embodiment.

  First, the configuration of the ultrasonic actuator 5 according to the present invention will be described with reference to FIG. FIG. 1A is a front view showing an outline of the overall configuration of the ultrasonic actuator 5, and FIG. 1B is a cross-sectional view taken along line AA ′ in FIG.

  As shown in FIG. 1A, the ultrasonic actuator 5 includes a vibrating body 10, a rotor 20, an FPC 30, a fixing member 40, and the like.

  The vibrating body 10 has an equilateral triangle shape, and a cylindrical rotor 20 circumscribes each vertex of the equilateral triangle. The rotor 20 corresponds to the moving body in the present invention, and before being assembled into the vibrating body 10, the size of each contact point is set to be smaller than the dimension of the vibrating body 10. Is elastically deformed (in the assembled state, the rotor 20 has a slightly triangular shape), and a predetermined pressing force is applied to each contact portion of the vibrating body 10 by the rotor 20.

  As shown in FIG. 1B, a V-shaped groove 20 a is formed in the circumferential cross section of the rotor 20. Since three convex chip members (contact portions) 103, which will be described later, provided at the vertices of the vibrating body 10 are fitted into the V-shaped groove 20a of the rotor 20, swinging in the thrust direction is restricted, The rotor 20 can rotate with high accuracy. A gel lubricant 201 is applied to the sliding surface (contacted portion) 20b of the rotor 20 on which the tip member 103 provided on the vibrating body 10 comes into contact and slides. Details of the gel lubricant 201 will be described later.

  As will be described later, the vibrating body 10 is held by three fixing pins 401 provided on the fixing member 40 in the vicinity of the center of each side where vibration is relatively small. Holding is performed by press-fitting or adhesion. Further, positioning with respect to the fixing member 40 may be performed by providing a notch in the vicinity of the center of each side of the vibrating body 10 and holding it by the fixing pin 401. The ultrasonic actuator 5 is positioned by fixing the fixing member 40 to, for example, a case or a frame of a magnetic recording apparatus described later.

  FIG. 2 shows a fixing method according to another example of the vibrating body 10. FIG. 2A is a front view illustrating an outline of the vibrating body 10, and FIG. 2B is a cross-sectional view taken along the line AA ′ in FIG.

  As shown in FIG. 2B, a through hole 10a may be provided at the center of gravity of the vibrating body 10 and fixed using a screw 403 or the like. Since the position of the center of gravity hits a vibration node, the influence on vibration due to fixation can be minimized.

  The material of the rotor 20 is preferably a highly elastic material, and a metal material such as stainless steel is used. In order to prevent wear, the surface is subjected to a hardening process such as a nitriding process. Moreover, you may perform ceramic coating, such as CrN and TiCN.

  An FPC (flexible printed wiring board) 30 is connected to the vibrating body 10, and a predetermined drive signal (described later) is input from a drive signal generation unit (not shown) through the FPC 30.

  When a drive signal is input to the vibrating body 10, high-frequency elliptical vibrations that rotate in the same direction are generated in three chip members 103 (described later) provided at each vertex of the vibrating body 10. Since the rotor 20 is in contact with the tip member 103 with a predetermined pressing force, the rotor 20 rotates by frictional force. In FIG. 1A, when each vertex performs elliptical vibration in the clockwise direction, the rotor 20 also rotates clockwise, and when each vertex performs elliptical vibration in the counterclockwise direction, the rotor 20 also rotates in the counterclockwise direction. Rotate. The speed and torque can be changed by changing the magnitude of the elliptical vibration.

  Since the rotor 20 is held by the three tip members 103 provided at the apex of the equilateral triangular vibrating body 10, the posture stability in the radial direction is very high, and the V-shaped groove is formed in the thrust direction. Since the swinging is restricted by 20a, there is no center deflection and the rotation is possible with very high accuracy. Further, since there is no backlash, the rigidity is high and the responsiveness of the motor can be improved. Moreover, since the location which hold | maintains the rotor 20 other than the three vertexes of the vibrating body 10 is not required, a drive loss is suppressed and high drive efficiency can be obtained.

  Next, the configuration of the vibrating body 10 will be described with reference to FIG. 3A is a front view showing the configuration of the vibrating body 10, FIG. 3B is a side view, and FIG. 3C is a back view.

  As illustrated in FIG. 3A, the vibrating body 10 includes three tip members 103 that abut on the rotor 20 and a piezoelectric member 101 having a plane portion formed at the apex of an equilateral triangle. The chip member 103 is coupled to the piezoelectric member 101 by adhesion. For bonding, an epoxy adhesive having high adhesive strength and high rigidity is used.

  As the material of the chip member 103, high hardness ceramics such as alumina and zirconia, cemented carbide or the like is used to prevent wear.

  The piezoelectric member 101 is made of a piezoelectric material exhibiting piezoelectric characteristics such as PZT (lead zirconate titanate), and a driving electrode is formed on the surface of the piezoelectric member a, and a common thin film electrode (GND electrode) 101c is formed on the surface b. . The electrode is made of silver or silver palladium and is formed by vapor deposition or the like. As shown in FIG. 3 (a), the driving electrode has a shape (six divisions) divided by each perpendicular extending from each vertex of the vibrating body 10 to the opposite side, and a pair of A-phase electrode regions at each vertex. , B-phase electrode regions, and each A-phase electrode 101a and each B-phase electrode 101b are commonly connected via the FPC 30. By connecting the FPC 30 in the vicinity of the position of the center of gravity of the triangle, which is a vibration node described later, the influence on the vibration can be minimized. For the connection, solder, conductive adhesive, or the like is used.

  Next, a method for driving the ultrasonic actuator 5 having such a configuration will be described. The basic driving method is elliptical vibration driving using resonance for rotating the rotor 20. This is a method of exciting and driving an elliptical vibration at each vertex of the vibrating body 10 by using resonance, and the amplitude can be expanded several tens of times, and a large elliptical vibration can be obtained efficiently at a low voltage. The principle and driving characteristics will be described below.

(Eigen mode)
First, the eigenmode will be described with reference to FIG. In order to excite elliptical vibration in the same rotational direction at each vertex of the vibrating body 10, in this embodiment, two eigenmodes shown in FIG. 4 are used. FIG. 4A is a schematic diagram illustrating a state of deformation of the vibrating body 10 in the stretching vibration mode, and FIG. In the stretching vibration mode, the center of gravity G of the vibrating body 10 is set as a vibration node, the three-divided region including each vertex is stretched and oscillated, and each vertex reciprocates radially in the same phase. In the bending vibration mode, the center of gravity position G of the vibrating body 10 is set as a vibration node, the three-divided region including each vertex is bent and vibrated, and each vertex is in the same phase and circumscribed around the center of gravity position G. Reciprocates in the tangential direction of the circumference of the circle. The stretching vibration mode can be excited by inputting a drive signal in phase with each A-phase electrode 101a and each B-phase electrode 101b, and the bending vibration mode by inputting a driving signal that matches each resonance frequency of the opposite phase.

(Phase difference driving method)
By substantially matching the resonance frequencies of the two eigenmodes described above and inputting the drive signals VA and VB having the same frequency as the resonance frequency shifted by 90 degrees in phase to the A-phase electrode 101a and the B-phase electrode 101b, The eigenmodes are excited and synthesized, and elliptical vibrations in the same rotational direction are generated at the vertices of the vibrating body 10. By reversing the phases of the drive signals VA and VB, the rotational direction of the elliptical vibration is reversed. Further, by changing the amplitude and phase of the drive signals VA and VB, the locus shape and size of the elliptical vibration can be changed.

  The elliptical locus diameter changes in proportion to the amplitude (voltage). Further, the elliptical shape can be changed by changing the phase difference between the drive signals VA and VB. FIG. 5 is a schematic diagram showing how the elliptical locus changes with respect to the phase difference between the drive signals VA and VB. 5A shows a case where the phase difference between the drive signals VA and VB is 45 °, FIG. 5B shows 90 °, and FIG. 5C shows 135 °. When the phase difference decreases, the elliptical diameter in the normal direction N at the contact point with the rotor 20 increases, and when the phase difference increases, the diameter in the tangential direction T increases. By changing the shape of the elliptical trajectory, the drive characteristics can be changed as described later, so that it can be applied to speed control and position control. In addition, by performing phase difference driving driven by the two-phase driving signals VA and VB, it is possible to drive at a low voltage and drive control based on the phase difference is possible.

(Single phase drive method)
By shifting the resonance frequency of the above-mentioned two eigenmodes by a predetermined value and inputting a single-phase drive signal having a frequency between them to either the A-phase electrode 101a or the B-phase electrode 101b, Elliptical vibration in the same rotational direction is excited. By switching the input electrode, the rotation direction of the ellipse can be reversed. By shifting the resonance frequency of each eigenmode by a predetermined value, the excitation of one of the electrodes drives the two eigenmodes out of phase and generates elliptical vibration. Since it can be driven by a single-phase drive signal, the drive circuit can be simplified and the cost can be reduced.

(Resonance frequency adjustment method)
The resonance frequencies of the two eigen modes can be set in a predetermined relationship by adjusting the hole diameter by providing a hole in the mass of the chip member 103 or the center of gravity of the vibrating body 10. In addition, the error in the resonance frequency of the two eigenmodes during manufacturing can be adjusted by post-processing or the like.

(Oval trajectory and drive performance)
Here, the relationship between the elliptical trajectory and the driving performance will be described with reference to FIG. When the elliptical vibration generated in the tip member 103 is decomposed into the tangential direction T and the normal direction N of the rotor 20, the speed of the rotor 20 is determined by the speed of the tip member 103 in the direction of elliptic motion T. It is determined by the diameter Rt of T and the driving frequency, and the speed increases as Rt increases. On the other hand, the driving force is determined by the product of the applied pressure and the friction coefficient of the contact point, but the diameter Rn in the normal direction N of the elliptical locus is also related. This is because when the applied pressure is relatively low with respect to the diameter Rn in the pressurizing direction of the elliptical locus, the tip member 103 is driven by frictional force during contact while repeatedly making contact with and separating from the rotor 20. However, when the applied pressure is relatively large with respect to the diameter Rn, elliptical vibration is performed in a constantly contacted state due to the elastic deformation of the rotor 20 or the contact portion surface or the elastic deformation of the structural member receiving the applied pressure. . In this state, since the friction force acts and acts as a brake even when the tip member 103 moves in the counter-drive direction during the vibration cycle, a drive force exceeding the value determined by Rn is not generated even if the applied pressure is increased. In the driving in such a state, the driving state such as speed unevenness and reproducibility becomes unstable, and there may be a problem such as abnormal noise. Therefore, the driving force increases as the diameter Rn of the elliptical locus in the pressing direction increases, and stable driving is possible.

  Therefore, the elliptical trajectory shown in FIG. 5 (a) has a low speed and high torque characteristic, and the elliptical trajectory shown in FIG. 5 (c) has a high speed and low torque characteristic. By changing the phase difference between the drive signals VA and VB, driving is performed. The performance can be controlled, and high-precision driving such as constant speed control and positioning control can be performed.

(DC drive)
Next, DC driving will be described. The DC drive is a driving method for swinging the rotor 20 minutely, and is used when very high-precision positioning is required, and a positioning resolution on the order of nm can be obtained. After performing coarse movement (high speed, wide rotation angle drive) by the above-described resonance drive and fine movement by DC drive, a drive system capable of wide-range, high-speed drive and high-accuracy positioning can be realized.

  As a driving method, by applying a DC voltage only to the A-phase electrode 101a, the three-divided region including each vertex of the vibrating body 10 is bent in the CCW direction as shown in FIG. The tip of the chip member 103 falls in the CCW direction. The rotor 20 in frictional contact with the tip member 103 moves (rotates) by the same amount by the frictional force, and returns to the original state when voltage application is stopped. Similarly, by applying a DC voltage only to the B-phase electrode 101b, the rotor 20 can be moved in a small amount in the CW direction. Further, when a DC voltage is applied to the A-phase electrode 101a, a negative voltage is applied to the B-phase electrode 101b, whereby the bending amount of the vibrating body 10 is increased and the rotation amount of the rotor 20 can be increased.

  In the ultrasonic actuator 5 having such a configuration, the present invention improves durability by suppressing wear between the tip member 103 of the vibrating body 10 and the sliding surface 20b of the rotor 20, and is generated from the sliding portion. A gel lubricant 201 is applied to the sliding surface 20b of the rotor 20 in order to increase the cleanliness by preventing the leakage of wear powder or lubricating oil to the outside of the actuator unit. Details will be described below.

(Operation of gel lubricant)
A sufficient amount of the gel lubricant 201 is applied to the sliding surface 20 b of the rotor 20. In particular, the process is very simple because it is not necessary to apply an accurate film thickness.

  When the vibrating body 10 is incorporated in the rotor 20 and starts to be driven, the gel-like lubricant 201 that has been stepped on the tip member 103 is liquefied by elliptical vibration, and the excess gel-like lubricant 201 is slid on the sliding surface 20b. Pushed out of the moving area. FIG. 7 shows an aspect of the gel lubricant 201 after the tip member 103 of the vibrating body 10 has passed. As shown in FIG. 7, the pushed-out gel-like lubricant 201 forms a bank-like swelled portion 201 b in the form of a gel on the side of the sliding region S. The liquefied gel lubricant 201a can remain on the sliding surface 20b without leaking to the outside due to the swelling. By liquefying, even if the reciprocating operation is very fast, the permeation speed of the gel-like lubricant 201a is fast, so that it is possible to drive by always forming a good oil film and to suppress wear. Moreover, since the viscosity is low, attenuation of vibration of the vibrating body 10 can be suppressed, and high driving performance can be ensured. When the driving is stopped, the liquefied gel lubricant 201a on the sliding surface 20b gradually starts to gel, so that the volatile components due to liquefaction can be minimized. When driving is started again, the gel lubricant 201 on the sliding surface 20b is liquefied again to form a good oil film.

  In addition, you may provide uneven | corrugated shape in the sliding surface 20b of the rotor 20, as shown in FIG. FIG. 8A is a development view of the sliding surface 20b of the rotor 20, and FIG. 8B is a cross-sectional view taken along the line BB ′ in FIG. 8A.

  The concave / convex shape is preferably such that the convex portion 20d is a flat surface having a center line average roughness of about 0.5 μm or less and the concave portion 20c is formed to a depth of 10 μm or more. In this case, the tip member 103 of the vibrating body 10 is driven while forming a lubricating film with the flat surface of the convex portion 20d, and a part of the liquefied gel lubricant 201a is accumulated in the concave portion 20c. Therefore, the time until the gel-like lubricant 201 scraped off by the tip member 103 permeates and returns to the sliding surface 20b is shorter than in the case of a single plane because the oil reservoir is close. Therefore, a good lubricating film can be formed even when the reciprocating operation is performed at a higher speed. The concavo-convex shape can be formed by molding the concavo-convex shape on the surface of the press mold at the time of manufacturing the rotor 20 and press-transferring it. The same effect can be obtained even if a minute hole is provided instead of the recess 20c.

(Liquefaction phenomenon of gel lubricant)
In this embodiment, the frequency of the elliptical vibration of the vibrating body 10 is about 200 kHz, and the tip member 103 repeatedly collides with and separates from the rotor 20 at a speed of 200 kHz. As a result, heat of several hundred degrees is locally and instantaneously generated between the tip member 103 of the vibrating body 10 and the sliding surface 20b of the rotor 20. The gel-like lubricant 201 is liquefied by the heat at that time and the shearing force during driving. Further, when there is no lubricating oil, the heat generated at that time oxidizes the metal surface of the rotor 20 and becomes one of the causes of wear. In this embodiment, the heat is absorbed by the gel lubricant 201. Therefore, it leads to reduction of wear.

  As described above, the gel-like lubricant 201 in the vicinity of the tip member 103 is liquefied or reduced in viscosity as the ultrasonic vibration by the tip member 103 is applied, and gels during the suspension of the ultrasonic vibration. . In addition, the viscosity of the gel-like lubricant 201 is reduced to 1/10 or less when liquefied from the gel state.

(Material for gel lubricant)
The gel-like lubricant 201 used in this embodiment uses a naphthenic mineral oil, a synthetic oil such as PAO (synthetic hydrocarbon) or ester as a liquid base oil, and a gelling agent such as wax or higher fatty acid. About 10 to 30% is blended. The gelling agent has a melting point of about several tens to 150 ° C., and the gel lubricant 201 reversibly changes between a gel and a liquid at temperatures before and after that.

  By using naphthenic traction oil as the base oil, the friction coefficient can be increased and the thrust of the ultrasonic actuator 5 can be improved. In addition, since the ester has low volatility, the amount of evaporation can be further reduced.

  Also, in the lubrication drive of the ultrasonic actuator 5, since the pressure is high and the speed is relatively slow, it is difficult to obtain a fluid lubrication or elastohydrodynamic lubrication state that forms a complete oil film, and there are minute irregularities on the contact surface. The boundary lubrication state in which a part of them comes into contact with each other is achieved. Therefore, the wear resistance is further improved by blending an extreme pressure agent such as sulfur, phosphorus, or molybdenum as an additive for the lubricant. However, although some abrasion powder may be generated, it is not discharged to the outside because it is diffused in the oil. Moreover, you may mix | blend additives, such as antioxidant, as needed.

  Next, an embodiment of a magnetic recording apparatus using the ultrasonic actuator 5 having such a configuration for driving a magnetic recording head will be described.

  An actuator used to drive a magnetic recording head (hereinafter abbreviated as “head”) of a conventional magnetic recording apparatus (hereinafter referred to as “HDD”) is configured to rotatably support an arm to which a head is attached by a pivot bearing. (Voice coil motor) is used for driving. When an HDD head is driven, it is necessary to perform positioning control while following the waviness of a track on a disk rotating at high speed, and the actuator is required to have very high responsiveness and resolution. As the responsiveness increases, the recording density increases, so that the recording capacity of the HDD can be increased.

  However, since the conventional actuator configuration uses a bearing, if the frequency of the oscillating operation is increased, unnecessary vibration caused by the bearing backlash is excited, and the responsiveness can be increased beyond the resonance frequency. There is no problem. By using the ultrasonic actuator 5 according to the present embodiment for driving the head of the HDD, it is possible to cope with such a problem.

  FIG. 6 shows a schematic configuration of the HDD 1A according to the embodiment of the present invention. The HDD 1 </ b> A includes a recording disk (recording medium) 2, an arm 4 rotatably provided in the direction of arrow A (tracking direction) by the ultrasonic actuator 5, a head 3 attached to the tip of the arm 4, and the disk 2. The housing 1 is provided with a motor (not shown) that rotates the head 3 in the direction of arrow B, and the head 3 can move relative to the disk 2.

  As described above, the ultrasonic actuator 5 has a configuration free from backlash that rotates while holding the vibrating body 10 by the elasticity of the rotor 20, and can hold the rotor 20 at each vertex of the regular triangle of the vibrating body 10. So the holding stability is very high. Therefore, the resonance frequency of the ultrasonic actuator 5 can be increased, and very high responsiveness can be obtained as compared with the conventional case.

  The recording area on the disk 2 is about 30 ° as the driving angle of the arm 4, while the waviness of the track is several nanometers to several tens of micrometers. Therefore, positioning with high response is required. The ultrasonic actuator 5 according to the present embodiment can meet these requirements by combining the coarse movement by the resonance drive and the fine movement by the DC drive, and further has a very simple configuration. Increase the manufacturing cost.

  In addition, the disk chamber (not shown) of the HDD 1A maintains a very high cleanliness, and is strictly controlled such as contamination (dust) and outgassing of members. Therefore, it is strictly prohibited that wear powder or oil leaks from the actuator unit, and it is necessary to suppress the volatile component of the oil as much as possible. By using the ultrasonic actuator 5 according to the present embodiment, these requirements can be satisfied easily and inexpensively.

  Moreover, since oil does not leak out, it becomes possible to mix | blend additives, such as an extreme pressure material considered to be harmful to HDD1A, and can improve durability dramatically. If such functions are realized with conventional oils or greases, expensive units such as a magnetic fluid seal for preventing discharge are required for the unit, and the assembly becomes complicated.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be changed or improved as appropriate. For example, in the above-described embodiment, the triangular rotor 20 is inscribed in the cylindrical rotor 20 so as to generate a relative circular motion. However, the vibrator is disposed in a pair of parallel shapes. A so-called linear drive configuration may be used in which the guide is movably supported and relatively linearly moved.

  Moreover, the gel-like lubricant 201 is not limited to the above-mentioned material, and may be any as long as it exhibits the same behavior.

  Further, the use of the ultrasonic actuator 5 according to the present embodiment is not limited to the HDD 1A. For example, the same effect can be obtained by using the ultrasonic actuator 5 for a device sensitive to oil leakage or dust mixing such as a lens driving device. Can do.

Claims (8)

A vibrating body having a contact portion for performing predetermined vibration;
The contact portion is in pressure contact has a contacted portion which includes a sliding region that slides relative to the contact portion by the vibration of the contact portion, by Ri before Symbol vibrator on the slide An ultrasonic actuator comprising a moving body that generates relative movement with respect to
The front Symbol contacted portion, a lubricant is applied blended with a gelling agent,
The lubricant applied to the contacted portion is pushed away from the sliding region by the vibration in a state where the contacting portion is in pressure contact with the sliding region, and the gel is placed outside the sliding region. The bulge part of the lubricated lubricant is formed,
Wherein the sliding region, the contact portion is liquefied by vibrating in contact pressure, or ultrasonic actuator the lubricant, characterized in Rukoto fastened by the raised part viscosity is lowered. The vibrator has a plurality of the abutting portions directed outward from the center,
The moving body has a cylindrical shape that circumscribes the plurality of contact portions,
A groove is formed in the contacted portion along the moving direction of the moving body,
The ultrasonic actuator according to claim 1 , wherein the contact portion vibrates in a state of being fitted in the groove . The lubricant in the vicinity of the contact portion is
Wherein with the ultrasonic vibration by the abutment portion is applied, reduces the liquefaction or viscous, ultrasonic actuator according to claim 1 or 2, characterized that you gel during pauses ultrasonic vibration . The ultrasonic actuator according to claim 3 , wherein the lubricant is a mineral or synthetic base oil blended with a wax or a higher fatty acid . Base oil of the lubricant, the ultrasonic actuator according to claim 4, characterized in Oh Rukoto with traction oil. The ultrasonic actuator according to claim 5 , wherein an extreme pressure agent is added as an additive to the lubricant . Claim 1 wherein the person contacted portion of the contact portion and the moving body or one of the contact surfaces that any of the vibrating member, characterized by Rukoto plurality of recesses or holes for storing the lubricant is formed The ultrasonic actuator of any one of thru | or 6 . A recording medium for recording information;
A magnetic head for reading and writing the information on the recording medium;
An arm that supports the magnetic head to be movable relative to the recording medium;
A magnetic recording apparatus comprising: the ultrasonic actuator according to claim 1, wherein the arm is fixed to the moving body provided in the ultrasonic actuator.