JP2638071B2 - Head moving device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The head moving device of the present invention will be described according to the following items.

A. Industrial application fields B. Summary of the invention C. Prior art a. General background b. Example of conventional head moving device [Fig. 10] D. Problems to be solved by the invention [Fig. 10] E Means for Solving the Problems F. Embodiment [FIGS. 1 to 9] F-1. First Embodiment [FIGS. 1 to 6] a. Magnetic Disk Cassette [FIGS. 3] b. Magnetic disk driver [FIGS. 1 to 6] b-1. Disk drive unit, cassette carrier [FIGS. 1 and 3] b-2. Head moving device [FIGS. 1 to 6] Figure] b-2-a. Base [Fig. 1 to Fig. 5] b-2-b. Coarse motor and lead screw [Fig. 1 to Fig. 3, Fig. 5] b-2-c. Moving lever [Fig. 1 to Fig. 5] b-2-d. Electrostrictive element [Fig. 1, Fig. 2, Fig. 5, Fig. 6] b-2-e. Displacement of lead screw [Fig. Figure 2] b-2-f. Head carriage FIGS. 1 and 3] b-3. Operation F-2. Second Embodiment [FIGS. 7 to 9] a. Support shaft b. Rotating lever c. Function G. Effect of the invention (A The present invention relates to a novel head moving device. For more information,
For example, it supports a recording / reproducing head for recording and / or reproducing on the recording medium in contact with a recording medium such as a magnetic disk, and moves the head carriage supported movably in the radial direction of the disk and the head carriage. A head moving device having a moving means for moving the head screw, particularly a coarse movement mechanism including a coarse movement motor and a lead screw rotated by the motor and engaged with the head carriage; It is composed of a rotating lever that displaces in the axial direction (radial direction of the disc) and a fine movement mechanism that finely rotates the rotating lever. The head carriage is coarsely moved and finely moved by rotating the lead screw by a coarse movement motor. By rotating the rotating lever by the mechanism, the lead screw is displaced in the axial direction. The present invention relates to a head moving device for finely moving a head carriage, and by devising a support structure of a rotating lever, a fine movement adjustment operation can be smoothly performed, and a highly accurate head position can be controlled. It is an object of the present invention to provide a new head moving device which can be used.

(B. Summary of the Invention) A head moving device according to the present invention includes a head for accessing a disc, a head carriage supporting the head and supported on a chassis so as to be movable in a radial direction of the disk, and a head carriage. A lead screw in which the part is engaged, fixed to the chassis, a coarse motor for coarsely moving the head carriage in the radial direction of the disk by rotating the lead screw,
A rotating lever having one rotating end abutting against one end of the lead screw, and the rotating lever supported so that the rotating end is displaced in a direction substantially the same as the radial direction of the disk; Movable means for freely moving the rotation fulcrum portion, biasing means for biasing the rotation lever to the rotation, and finely moving the other rotation end of the rotation lever to move the lead screw. Fine movement means for finely moving the head carriage in a radial direction of the disk by displacing the disk in a radial direction of the disk. Of the lead screw does not move in the direction intersecting the axial direction of the lead screw (radial direction of the disk), thereby preventing the shaft of the lead screw from moving. Direction smoothly perform fine movement in the (radial direction of the disk), and is obtained by so may perform control with high precision head position.

(C. Prior Art) (a. General Background) For example, a recording / reproducing device such as a magnetic disk driver includes a recording / reproducing head which faces a recording medium such as a magnetic disk and performs recording and / or reproduction on the recording medium. Is provided, and such a head carriage is normally movably supported in a radial direction of the disk and is moved by a moving mechanism driven by a motor.

Conventionally, there are various types of such moving mechanisms. Among them, a motor and a lead screw rotated by the motor and engaged with a part of a head carriage are provided. In some cases, a so-called stepping motor is often used as the motor, for example, by moving the head carriage by rotating the motor.

By the way, in order to increase the recording density on a recording medium such as a magnetic disk, it is necessary that the recording medium itself has a quality suitable for high-density recording, and the operation of a recording / reproducing device, particularly, a head moving device Therefore, a moving mechanism capable of controlling the position of the head carriage at a high accuracy is required.

In this case, in the case where the stepping motor and the lead screw are used as the moving mechanism, it is conceivable to reduce the rotation pitch of the stepping motor as much as possible, but the rotation pitch is reduced without increasing the shape of the motor. There are certain limits to doing so.

(B. One example of a conventional head moving device) [FIG. 10] In order to improve the accuracy of the position control of the head carriage, it is proposed to move the head carriage by two moving mechanisms, a coarse moving mechanism and a fine moving mechanism. Has been
Examples of such a head moving device include Japanese Patent Application No. 62-204334 and Japanese Patent Application No. 62-167546.

FIG. 10 schematically shows a head moving device a disclosed in Japanese Utility Model Application No. 62-167546.

In the drawing, reference numeral b denotes a head carriage that supports a recording / reproducing head e that is movably supported by a guide shaft c and that comes into contact with and separates from a magnetic disk d. Reference numeral a denotes a base of the head moving device a. A coarse movement motor g and a fine movement motor h are fixed to the base f, and an intermediate portion of the rotation lever i is rotatable at a position facing the motors g and h. The rotation lever i is urged by a tension spring j such that one rotation end is constantly moved to the coarse motor g.
k is a lead screw arranged so that a part of the head carriage b is engaged and extends in parallel with the moving direction of the head carriage b. One end of the lead screw is provided at one rotation end of the rotation lever i. And the other end is the rotor shaft of the coarse movement motor g. The spring lever (not shown) having an elastic force smaller than the tension force of the tension spring j always rotates the lever i side. Pressed toward. m is a string-like member formed by fixing both ends of two wires n and n 'together by fixing members o and p, respectively, and a hooking piece q1 is integrally formed on one fixing member o; The hook piece q is rotatably locked to a hook shaft r provided upright at the other rotation end of the rotation lever i, and the other fixing member p is connected to the rotation shaft s of the fine movement motor h. Connected,
When the head carriage b is at the movement origin, the two wires n and n 'are appropriately twisted so as to be entangled with each other.

Accordingly, the rotating lever i has its two rotating ends pulled toward the motors g and h by the string member m and the tension spring j, and the string member m is rotated by the rotation of the fine movement motor h. Since the length is changed by increasing or decreasing the amount of torsion, when the amount of torsion of the string-like member m is increased, the length of the string-like member m is shortened. The other rotating end of i is pulled to rotate the lever i
Is turned in the counterclockwise direction in the figure, and when the cord-like member m is untwisted, the length of the cord-like member m becomes longer, whereby the rotating lever i is moved by the tension spring j. Is rotated clockwise in FIG. When the rotation lever i rotates counterclockwise, the lead screw k is moved to the head carriage b.
When the rotating lever i rotates clockwise in the direction opposite to the motor g, the head is moved integrally with the head carriage b toward the motor g.

When the coarse motor g rotates, the lead screw k rotates to coarsely move the head carriage b, and the coarse movement causes the position of the recording / reproducing head e to reach a target track on the magnetic disk d. When the position does not coincide with the position, the fine-movement motor h rotates to twist or untwist the string-like member m.
Is moved in the axial direction to slightly move the head carriage b.

(D. Problems to be Solved by the Invention) [FIG. 10] In the conventional head moving device a shown in FIG.
Since the rotation fulcrum t of the rotation lever i is fixed to the base f, there is a problem that smooth operation is difficult and accuracy is not good.

That is, when the rotation lever i rotates, a portion u of the rotation lever i where one end of the lead screw k is in contact.
However, as shown in FIG. 10, it moves while drawing an arc v having a radius R. Therefore, although one end w of the lead screw k needs to be shifted laterally by the distance D, the lead screw k cannot move at all in the horizontal direction because it is supported by the bearing. Therefore, a position shift of the distance D occurs between the one end w of the lead screw k and the contact portion u of the rotating lever i, and such a position shift is forcibly performed.
The rotation operation of the rotation lever i, that is, the fine movement operation of the lead screw k is not smooth. The displacement between the one end w of the lead screw k and the contact portion u of the rotating lever i not only causes the accuracy to deteriorate itself, but also causes the rotation due to the repetition of such positional displacement. There is also a problem in that the backlash of the contact portion u of the lever i occurs and the one end w of the lead screw k is severely worn, so that the accuracy thereof is significantly deteriorated during use.

(E. Means for Solving the Problems) In view of the above, the head moving device of the present invention is configured such that the pivot point of the pivot lever is movable.

Therefore, in the head moving device of the present invention, when the rotation lever is rotated to cause a positional shift between one end of the lead screw and the contact portion of the rotation lever, the rotation fulcrum is moved to the position. Since it moves in the direction to absorb the displacement, no excessive force is generated between one end of the lead screw and the contact portion of the rotating lever, and therefore, the lead screw is rotated by rotating the rotating lever. Is performed smoothly, and the head position is controlled with high accuracy.

(F. Embodiment) [FIGS. 1 to 9] Hereinafter, details of the head moving device of the present invention will be described in accordance with each of the illustrated embodiments.

In each of the illustrated embodiments, the present invention is applied to a head moving device in a magnetic disk driver.

(F-1. First Embodiment) [FIGS. 1 to 6] First, an example of a magnetic disk cassette will be described.
After that, the magnetic disk driver will be described.

(A. Magnetic Disk Cassette) [FIGS. 1 and 3] Reference numeral 1 denotes a magnetic disk cassette.

Reference numeral 2 denotes a thin box-shaped cassette case, in which a circular hole 4 is formed at a substantially central portion of one of the two wall portions 3 and 3 'facing each other in the thickness direction. Head insertion holes 5 and 5 'are formed on one side of 3'. The head insertion holes 5 and 5 'are opened by a shutter (not shown) while the magnetic disk cassette 1 is not mounted on a magnetic disk driver described later. It is closed.

Reference numeral 6 denotes a thin sheet-shaped magnetic disk which is rotatably housed in the cassette case 2 and has a center core 7 attached to the center thereof and a main engagement hole 7a and a driven hole 7b is formed, and the center core 7 is located so as to face the outside from the center hole 4 of the cassette case 2.

(B. Magnetic Disk Driver) [FIGS. 1 to 6] 8 is a magnetic disk driver, and 9 is its mechanical chassis.

(B-1. Disk drive unit, cassette carrier) [First
3 is a front end of the mechanical chassis 9 (a leftward direction in FIG. 1 is a front side, a rightward direction is a rear side, and an upward direction in the same figure is a left side. The downward direction is defined as the right side. In the following description, this direction is used when indicating the direction.) A disk drive motor (only a part is shown in the drawing) disposed at a position closer to the disk drive motor. A rotating plate 12 is fixed to the upper end of the rotating shaft 11, and a driving pin 13 projects from the rotating plate 12.

Reference numeral 14 denotes a cassette carrier movably supported in a vertical direction by a guide means (not shown) provided on the mechanical chassis 9, wherein the magnetic disk cassette 1 is removably inserted, and the magnetic disk cassette 1 is moved to a predetermined insertion position. When inserted, it is moved to the bonding position indicated by the solid line in FIG. When the cassette carrier 14 comes to the mounting position, the magnetic disk 6 of the magnetic disk cassette 1 is moved.
The center core 7 is mounted on the rotary plate 12 and the drive pins 13 and the portions of the rotary shaft 11 of the motor 10 projecting upward from the rotary plate 12 are separately engaged with the engagement holes 7a and 7b, respectively.
As a result, the magnetic disk 6 is rotated integrally with the rotating plate 12.

(B-2. Head Moving Device) [FIGS. 1 to 6] Reference numeral 15 denotes a head moving device, which includes a base fixed to the mechanical chassis 9, a coarse motor fixed to the base,
A lead screw rotated by a coarse motor, a rotating lever rotatably supported by the base and having one rotating end in contact with the end opposite to the motor of the lead screw, and the other rotating of the rotating lever An electrostrictive element, which is a fine movement mechanism connected between the end and the base, supports a magnetic head that comes into contact with and separates from the magnetic disk, and is supported by a mechanical chassis 9 movably in the front-rear direction and leads It consists of a head carriage and the like engaged with the screw.

(B-2-a. Base) [FIGS. 1 to 5] Reference numeral 16 denotes a base. Reference numeral 17 denotes a main portion of the base 16, which has a substantially rectangular plate shape long in the front-rear direction, and a substantially rectangular motor mounting wall 18 long in the left-right direction is integrally formed at a rear end thereof, and a left end of an upper surface thereof. A screw support wall 19 is provided upright at a position slightly backward from the front end of the portion, and the right end of the screw support wall 19 and the motor mounting wall 18 are connected to the reinforcing wall 20.
Are connected by

Reference numeral 21 denotes a spring hook piece protruding leftward from a position near the rear end of the left end surface of the main portion 17, and 22 denotes an upward direction from the screw support wall 19 of the main portion 17 slightly obliquely to the front. The supporting shafts 23 and 23 'are provided with mounting holes formed in the main portion 17,
24 is a notch for fixing the position.

Further, reference numeral 25 denotes a support portion projecting rightward from the rear end of the main portion 17, and a support shaft 26 stands upright from the support portion 25.

The main part 17 of the base 16 is a mechanical chassis 9.
(Only two of them are shown in the drawings) provided on the upper surface of the base plate, and the screws 28, 28, which are inserted through the mounting holes 23, 23 ', and A screw 28 'engaged with the notch 24 is fixed to the mechanical chassis 9 by being screwed to the base mounting base 27, 27,. It is pressed against the raised positioning walls 27a, 27a (see FIG. 1).
In this way, the base 16 is positioned with respect to the mechanical chassis 9.

(B-2-b. Coarse Movement Motor, Lead Clew) [FIGS. 1 to 3 and FIG. 5] Reference numeral 29 denotes a coarse movement motor.

Reference numeral 30 denotes a casing of the coarse movement motor 29, which has a cylindrical shape that is short in the axial direction, has a flange 30a formed at the front end thereof, and has an insertion hole 30c formed at the center of the front plate 30b. A resilient piece 31 is formed in the center of 30d in a cut-and-raised shape inward.

Reference numeral 32 denotes a stator mounted on the inner peripheral surface of the casing 30.

Reference numeral 33 denotes a column-shaped lead screw, and a spiral groove 34 is formed in a portion excluding a front end portion 33a and a rear approximately one-third portion 33b.
Are formed, and concave portions 33c, 33c 'which are hemispherical on both front and rear end surfaces.
Are formed, and the spherical body 35 is fixed to the concave portion 33c 'on the rear side.

Reference numeral 36 denotes a bearing arrangement hole formed substantially in the center of the screw support wall 19 of the base 16, and a bearing 37 is provided in the bearing arrangement hole 36.
Is press-fitted.

Reference numeral 38 denotes an insertion hole formed in the motor mounting wall 18 of the base 16 at a position facing the bearing 37, a rear portion 38a having a large diameter, and a ball bearing 39 formed in the large diameter portion 38a. Has been fixed.

The lead screw 33 has its front end 33a supported by the bearing 37 of the screw support wall 19, and its rear end portion is rotatably and slidably supported by the ball bearing 39 of the motor mounting wall 18, respectively. The casing 30 is coaxial with the lead screw 33 and has a flange 30a fixed to the rear surface of the motor mounting wall 18.

Reference numeral 40 denotes a rotor which is externally fixed to a portion of the lead screw 33 which protrudes into the casing 30.
A stepping motor is constituted by 40 and the stator 32.

Thus, when a driving current is supplied to the stator 32, a rotational force is applied to the rotor 40, whereby the lead screw 33 rotates.

As will be described in detail later, the lead screw 33 is pressed forward by the resilient piece 31 of the casing 30 and pressed rearward by a rotating lever described later, and these lead screws 33 are moved forward. It is held at a position where the balance of the pressing force is maintained.

(B-2-c. Rotating Lever 9 [FIGS. 1 to 5] 41 is a rotating lever.

The rotating lever 41 has a plate shape that is long in the left-right direction, and its left and right end portions 41a and 41b are located slightly below the remaining portions. A notch 42 is formed at the front edge of the left end 41a, and a mounting hole 43 is formed at the center of the right end 41b. A mounting hole 44 is formed at the center.

45 is a bearing mounting portion formed at a position between the mounting hole 44 of the rotating lever 41 and the left end portion 41a, has a cylindrical shape extending in the front-rear direction, and a circular concave portion 46 is formed on the rear surface thereof, A screw hole 47 is formed between the recess 46 and the front end surface.

Reference numeral 48 denotes a pivot bearing which is fitted in the recess 46, and has a thick disk-like support 48 having a recess which is opened on the rear surface.
a and a substantially dish-shaped open rear surface, a retainer ring 49 supported in the concave portion of the support body 48a, an annular press ring 50 arranged to close the open surface thereof, and a retainer ring 49 for holding the retainer ring 49. , And a plurality of spheres 51, 51,.

Reference numeral 52 denotes an adjusting screw screwed into the screw hole 47 of the bearing mounting portion 45.

Numeral 53 denotes a fulcrum arm, the rear half of which is formed in a fork shape so as to have a substantially U-shape when viewed from the side. The base is inserted into a supported hole 54 formed at the front end of the fulcrum arm 53.
The support shaft 22 erected from 16 is inserted therethrough, whereby the fulcrum arm 53 is rotatably supported by the base 16.

Reference numeral 55 denotes a shaft provided between the fork constituent pieces 56 and 56 of the fulcrum arm 53, and the shaft 55 is inserted through the mounting hole 44 of the rotating lever 41 located between the fork constituent pieces 56 and 56. Thus, the rotation lever 41 is rotatably supported by the rear end of the fulcrum arm 53.

In this manner, the rotating lever 41 is rotatably supported by the base 16 via the fulcrum arm 53.

The rotating lever 41 is a tension spring that is stretched between the notch 42 of the left end 41a thereof and the spring hook 21 of the base 16.
57 is always urged in the clockwise direction in FIG. 1 and is rotated in the above direction by an electrostrictive element described later connected between the right end 41b and the support 25 of the base 16. In accordance with a change in the length of the electrostrictive element, the element is turned counterclockwise against the tensile force of the tension spring 57, or the tension of the tension spring 57 is changed. Or clockwise.

(B-2-d. Electrostrictive element) [FIG. 1, FIG. 2, FIG.
FIG. 6, FIG. 6] 58 is an electrostriction effect element constituting the fine movement mechanism. The electrostrictive effect element 58 generates a strain in accordance with the applied voltage when a voltage is applied. For example, a multilayer chip capacitor structure using a material having a large electrostrictive effect such as piezoelectric ceramics is used. It is known that a large distortion is generated at a low voltage. An electrostrictive effect element having such a structure is disclosed, for example, in Japanese Patent Publication No. Sho 63-17355.

This electrostrictive effect element 58 has a prismatic appearance, 59,
Reference numeral 59 'denotes a lead wire for applying a voltage thereto, which is connected to a control circuit (not shown). When a voltage is applied to the electrostrictive effect element 58, a large strain is generated in the longitudinal direction.

Reference numerals 60 and 60 'denote connectors, which are substantially U-shaped when viewed from the side. That is, the intermediate pieces 61 and 61 ′ having a short length in the vertical direction
The connecting pieces 62, 62 and 62 ', 62' project from the upper and lower ends in the same direction. And each connecting piece 62, 62
And 62 ', 62' are formed with connecting holes 63, 63 and 63 ', 63'.

Then, the connecting members 60 and 60 ′ are fixed to both ends of the electrostrictive effect element 58. That is, on the front end face of the electrostrictive effect element 58, the surface of the intermediate piece 61 of the connector 60 on the side opposite to the connecting piece 62, 62 is fixed by fixing means such as adhesion, and on the rear end face of the electrostrictive effect element 58. The surface of the connecting piece 60 'on the side opposite to the connecting piece 62' of the intermediate piece 61 'is fixed by bonding or the like. Thus, the electrostrictive effect element 58
Connecting pieces 62, 62 and 62 ', 62' from above and below both end faces, respectively.
Is projected.

Therefore, the right end 41b of the rotating lever 41 is positioned between the front connection pieces 62 and 62, the mounting holes 43 are aligned with the connection holes 63 and 63 of the connection pieces 62 and 62, and these are attached to the mounting pins. At 64, it is rotatably connected. Thus, the front end of the electrostriction effect element 58 is rotatably connected to the right end 41b of the rotating lever 41. Also, the connection holes 63 ', 63' of the rear connection pieces 62 ', 62'.
A support shaft 26 erected on a support portion 25 provided at a rear portion of the base 16 is rotatably inserted, whereby the rear end of the electrostrictive effect element 58 is rotatably supported by the base 16. .

(B-2-e. Displacement of Lead Screw) [FIG. 2] The lead screw 33 is formed on the casing 30 of the coarse motor 29 on a spherical body 35 fixed to the concave right 33c 'formed on the rear end face. The ball 6 is pressed forward by the resilient piece 31 by contact with the resilient piece 31 and is disposed in a recess 33c formed on the front end surface thereof.
The roller 5 is rotatably abutted against a number of spheres 51, 51,... Of the pivot bearing 48 supported by the rotating lever 41, thereby defining its axial position.

Then, the voltage applied to the electrostrictive effect element 58 changes to decrease the length of the electrostrictive effect element 58, and
When the length of the rotation lever 41 is shortened, the right end 41b of the rotation lever 41 is pulled backward, so that the rotation lever 41 is rotated counterclockwise against the pulling force of the tension spring 57, and thereby the lead screw 33 is moved forward by the pressing force of the resilient piece 31 of the casing 30.

Further, when the voltage applied to the electrostrictive effect element 58 changes to increase the length of the electrostrictive effect element 58 and the length of the electrostrictive effect element 58 becomes longer, the amount of rotation corresponding to the increased length is rotated. The lever 41 is rotated clockwise by the tensile force of the tension spring 57, and presses the pivot bearing 48 and the lead screw 33 rearward, so that the lead screw 33 is moved from the resilient piece 31 of the casing 30. Will be moved backward against the pressing force of.

Then, the rotation lever 41 rotates, and the lead screw
When the pivot bearing 48, which is the contact portion with which the sphere 65, which is one end of the 33, is in contact with the spherical member 65 of the lead screw 33 and the pivot bearing 48, when the pivot bearing 48 is to be shifted laterally from the axis of the lead screw 33. Since a force is exerted to maintain the contact state with each other, the fulcrum arm 53 rotates, and the shaft 55 that is the rotation fulcrum of the rotation lever 41 moves.
The displacement is made smoothly in the axial direction of the shaft 33, and the pivot bearing 48 is always positioned on the axis of the lead screw 33, so that highly accurate adjustment is performed.

(B-2-f. Head Carriage) [FIGS. 1 and 3] Reference numeral 66 denotes a head carriage. The head carriage 66
Is a moving support 67 having an approximately L-shape when viewed from the right.
A head arm 68 whose rear end is hinged to the upper surface of the rear end of the moving support 67, a supported portion 69 protruding from the left end surface of the moving support 67, and the like. The magnetic heads 70 and 70 'for recording and reproduction are attached to the surfaces of the head arm 68 which are opposed to each other at the distal end.

Reference numeral 71 denotes a guide shaft arranged to be separated from the head moving device 15 to the left side, and to extend along the front-rear direction,
A support member 72 having both ends fixed to the mechanical chassis 9,
Supported by 72.

The head carriage 66 has a supported portion 69 slidably supported by the guide shaft 71 and an engaging pin 73 projecting rightward from the rear end of the moving support 67. The lead screw 33 is sandwiched from above and below by a leaf spring piece that is not
The engagement with the lead screw 33 is achieved by engaging with the spiral groove 34 formed in the 33. Therefore, the head carriage 66 is rotated by the rotation of the lead screw 33 and the engagement pin 73.
Is moved in the front-rear direction by being pressed in the front-rear direction, or is moved in the front-rear direction integrally with the lead screw 33 by displacing the lead screw 33 in the aforementioned direction.

The head arm 68 has a predetermined space between the magnetic head 70 'and the magnetic head 70 as shown by a two-dot chain line in FIG. 3 while the cassette carriage 14 is not at the mounting position. And is waiting at a position facing from above.

(B-3. Operation) Then, when the magnetic disk 6 of the magnetic disk cassette 1 is mounted on the rotating plate 12 of the disk drive motor 10,
The magnetic head 70 supported by the moving support 67 relatively contacts the lower surface of the magnetic disk 6 and the cassette carrier 14
The magnetic head supported by the head arm 68 by rotating the head arm 68 downward in conjunction with the downward movement of
70 'contacts the upper surface of the magnetic disk 6.

When the recording or reproducing operation is started, the magnetic disk 6 is rotated, and the head carriage 66 is moved to a position where the magnetic head 70 or 70 'is opposed to the designated track on the magnetic disk 6. .

The movement of the head carriage 66 is first performed by rotating the lead screw 33 of the coarse movement motor 29. When the movement causes the magnetic head 70 or 70 'to face the designated track, that is, the magnetic head When 70 or 70 'detects the specified track, recording or reading of a signal is started immediately without changing the voltage applied to the electrostrictive effect element 58, and the lead screw 33 is rotated and moved. In the case where the magnetic head 70 or 70 'does not face the designated track, the electrostrictive effect element
The applied voltage to 58 is varied in a predetermined direction, depending on whether the designated track is on the ascending or descending side with respect to the track on which the magnetic head 70 or 70 'is currently facing, whereby , As described above,
Is rotated clockwise or counterclockwise to move the lead screw 33 in the front-rear direction, thereby slightly moving the head carriage 66 in the front-rear direction, that is, in the tracking direction, whereby the magnetic head 70 or 70 ' Is controlled to face the designated track.

(F-2. Second Embodiment) [FIGS. 7 to 9] FIGS. 7 to 9 show a second embodiment 15A of the head moving device of the present invention.

Note that the second embodiment 15A is different from the first embodiment 15 only in the rotation fulcrum of the rotation lever, and the other parts are the same as in the first embodiment 15. Only the different parts will be described in detail, and the parts that are not different will be denoted by the same reference numerals as those of the similar parts in the first embodiment 15, and the description thereof will be omitted.

(A. Support shaft) Reference numeral 74 denotes a fulcrum shaft erected substantially at the center of the front end of the main portion 17 of the base 16, and includes a base and a head attached to the upper end of the base.

75 is a base portion, and the upper end portion is a cylindrical sliding contact portion 76 having a smaller diameter than the remaining portion, and the sliding contact portion 76 is formed with a screw hole 77 opened at the upper end surface thereof. .

Reference numeral 78 denotes a head having a diameter larger than that of the sliding portion 76 of the base 75, and a screw shaft 79 vertically provided from the center of the lower surface thereof is screwed into the screw hole 77 of the sliding portion 76.

(B. Rotating Lever) A sliding hole 80 extending in the longitudinal direction is formed in the center of the rotating lever 41A. The width of the sliding hole 80 is formed to be substantially the same as the outer diameter of the sliding portion 76 of the fulcrum shaft 74. Further, the thickness of the portion of the rotating lever 41A where the sliding hole 80 is formed is substantially the same as the height of the sliding contact portion 76 of the fulcrum shaft 74.

Then, by attaching the head 78 to the base 75 with the slidable portion 76 of the base 75 inserted through the sliding hole 80 of the rotation lever 41A with the fulcrum shaft 74, the rotation lever 41A It is supported rotatably and slidably. That is, the rotating lever 41A
Is pivotally movable with respect to the rotation lever 41A within the range of the slide hole 80.

(C. Action) Therefore, even in the second embodiment 15A, the rotation of the rotation lever 41A causes the sphere 6 at the tip of the lead screw 33 to move.
Even if 5 and the pivot bearing 48 are likely to be misaligned,
Since the rotating lever 41A slides on the fulcrum shaft 74 in a direction to absorb the positional deviation, the spherical body 65 and the pivot bearing 48 are always in contact on the axis of the lead screw 33.

(G. Effects of the Invention) As is apparent from the above description, the head moving device of the present invention has a head for accessing a disk, and supports the head, and is supported on a chassis so as to be movable in the radial direction of the disk. Head carriage, a lead screw engaged with a part of the head carriage, and fixed to the chassis, for rotating the head carriage in the radial direction of the disk by rotating the lead screw. A coarse movement motor, a rotating lever having one rotating end abutting on one end of the lead screw, and the rotating end supported to be displaced in a direction substantially the same as the radial direction of the disk. Movable means for freely moving a rotation fulcrum of the rotation lever, urging means for urging the rotation lever to rotate, and the rotation lever By fine movement of the other rotating end portion, characterized in that a fine movement means for finely moving said head carriage in the radial direction of the disk by displacing the lead screw in the radial direction of the disk.

Therefore, in the head moving device of the present invention, when the rotation lever is rotated to cause a positional shift between one end of the lead screw and the contact portion of the rotation lever, the rotation fulcrum is moved to the position. Since it moves in the direction to absorb the displacement, no excessive force is generated between one end of the lead screw and the contact portion of the rotating lever, and therefore, the lead screw is rotated by rotating the rotating lever. Is performed smoothly, and the head position is controlled with high accuracy.

In each of the above embodiments, the electrostriction effect element is shown as the fine movement mechanism. However, the gist of the present invention resides in the rotation fulcrum of the rotation lever, and the fine movement mechanism is the same as that shown in the above embodiment. The present invention is not limited to this, and may be another one. For example, the fine movement mechanism using the fine movement motor g and the string-shaped member m shown in the conventional example can also be applied.

[Brief description of the drawings]

FIGS. 1 to 6 show a first embodiment in which the head moving device of the present invention is applied to a head moving device in a magnetic disk driver. FIG. 1 is a schematic plan view of the entire magnetic disk driver. FIG. 3 is an enlarged horizontal sectional view of the head moving device, FIG. 3 is a sectional view taken along the line III-III of FIG. 1, FIG. 4 is a sectional end view taken along the line IV-IV of FIG.
FIG. 6 is an enlarged perspective view of the head moving device, FIG. 6 is an enlarged perspective view of the moving mechanism in a state before being incorporated in the head moving device, and FIGS. 7 to 9 are second views of the head moving device of the present invention.
7 is a plan view, FIG. 8 is a perspective view, FIG. 9 is an exploded perspective view of a main part, and FIG. 10 is a schematic plan view showing an example of a conventional head moving device. is there. Description of symbols 9: Chassis, 15: Head moving device, 29: Motor for coarse movement, 33: Lead screw, 33a ... One end of (lead screw), 41: Rotating lever, 41a: Turn One rotating end of the moving lever, 41b... The other rotating end of the rotating lever, 44, 55... Movable means of the rotating fulcrum of the rotating lever, 57. …… fine movement means,
66 …… Head carriage, 70, 70 ′ …… Head, 15A…
… Head moving device, 41A …… Rotating lever, 74, 80 …… Movable means of the fulcrum of the rotating lever

Claims (1)

(57) [Claims] 1. A head for accessing a disk, a head carriage supporting the head and supported on a chassis movably in a radial direction of the disk, and a lead screw engaged with a part of the head carriage. A coarse motor that is fixed to the chassis and coarsely moves the head carriage in the radial direction of the disk by rotating the lead screw; and one rotating end of the motor rotates one end of the lead screw. A rotating lever to be brought into contact with, a movable means for freely moving a rotating fulcrum of the rotating lever supported such that the rotating end is displaced in a direction substantially the same as the radial direction of the disk; Urging means for urging the rotating lever to rotate, and finely moving the other rotating end of the rotating lever to move the lead screw of the disk Fine movement means for finely moving the head carriage in the radial direction of the disk by displacing the head carriage in the radial direction.