JPH0548297Y2 - - Google Patents

Description

[Detailed Description of the Invention] The rotary recording medium drive device of the present invention will be explained according to the following items.

A. Field of industrial application B. Overview of the invention C. Prior art [Fig. 6] D. Problem that the invention aims to solve E. Means for solving the problem F. Example a. Spindle mechanism [Fig. 1, 2] ] b Moving body, guide shaft [Figures 1 to 3] c Arm [Figures 1, 3] d Cam gear [Figures 1, 2, 4] e Maintaining the posture of the moving body f Feed gear, motor [Fig. 1, Fig. 2] g Magnetic disk cassette [Fig. 1, Fig. 2,
FIG. 5] h Recording and reading G Effects of the invention (A Field of industrial application) The present invention relates to a novel rotary recording medium drive device. Specifically, for example, rotary recording medium drive devices such as magnetic disk drive devices installed in various information processing devices and electronic still cameras that use magnetic disks called floppy disks as recording media, etc. Specifically, the apparatus includes a rotating means for rotating a rotary recording medium, a moving body that supports a head and is moved in a direction substantially perpendicular to the recording track of the rotary recording medium, and a moving means for moving the moving body. Recording or reading on or from a rotary recording medium is performed using a rotary recording medium drive device in which the head faces the rotating rotary recording medium. The means for keeping the attitude of the moving object constant so that it does not tilt relative to the object is extremely simple and can be constructed with a small shape, and the attitude of the moving object can be reliably kept constant. In this way, the present invention aims to provide a novel rotary recording medium drive device that allows this type of device to be made considerably smaller and lighter.

(B Overview of the invention) The rotary recording medium drive device of the present invention comprises a rotating means for rotating a rotary recording medium, a moving body that supports a head, and is moved in a direction substantially perpendicular to the recording track of the rotary recording medium. A rotary recording medium drive device comprising a moving means for moving the movable body, and recording or reading on the rotary recording medium is performed with the head facing the rotating rotary recording medium, wherein the movable body is A pin portion provided on the movable body is slidably supported by a guide shaft supported by the chassis and is slidably engaged with a cam groove formed in a cam gear rotated by a rotation means. ,
The distal end portion is attached to the movable body, the base end is fixed to the chassis, and an arm having spring elasticity is provided in the intermediate portion thereof to be elastically displaced as the movable body moves, and the movable body is configured so that its pin portion is pressed against the inner circumferential surface of the cam groove by the arm and slides on the guide shaft as the cam gear rotates. This ensures that the posture is always maintained constant.

(C Prior Art) [Figure 6] Nowadays, there are various types of information recording media such as magnetic disks, magnetic tapes, optical disks, and IC memories. Magnetic disks are used as appropriate depending on the amount of information, etc. Among these, magnetic disks have sufficient storage capacity despite their small size, and the structure of the recording and reproducing device that uses them is relatively simple. It has many advantages, such as being extremely thin, making it convenient to store, and furthermore allowing random access.

By the way, the most important parts of recording and reproducing equipment that use magnetic disks, and which require high precision in their operation, are the spindle mechanism that rotates the magnetic disk and the moving direction of the moving body that supports the magnetic head. This magnetic disk drive device includes a guide mechanism for guiding, a moving mechanism for moving the moving body, and the like.

In particular, the guide mechanism needs to guide the movable body in a state where its posture is always maintained constant, that is, in a state where the orientation with respect to the magnetic disk does not change when it is moved. For magnetic disks, the precision of maintaining the posture is normally required to be on the order of microns.

For this reason, in conventional magnetic disk drive devices, two guide shafts extending parallel to each other are provided on the chassis, and the movable body is supported by these two guide shafts.

FIG. 6 shows an example a of a conventional magnetic disk drive device having two such guide shafts.

In the figure, b is a main chassis, c is a spindle that is located approximately in the center of the main chassis b and is rotatably supported, and the spindle c
is rotated by a spindle motor (not shown) provided on the lower surface of the main chassis b. Reference numeral d denotes a magnetic disk cassette in which a magnetic disk e is housed, and a window f is formed to expose a part of the magnetic disk e to the outside. By being attached to the device a, the center core g fixed at the center of the magnetic disk e is engaged with the spindle c. This brings the magnetic disk e into a state where it is rotated integrally with the spindle c.

h is a moving body on which magnetic head i is supported,
The movable body h is slidably supported by two guide shafts j and k provided on the main chassis b so as to extend parallel to each other at both ends thereof in the longitudinal direction, and the magnetic disk cassette d is supported as described above. By being mounted in this manner, the magnetic head i is positioned so as to be in relative contact with the magnetic disk e through the window f, and the magnetic head i is moved in the radial direction of the magnetic disk e. has been done.

l is a cam gear. The cam gear l is located on the lower surface side of the main chassis b, is rotatably supported by a support shaft m projecting downward from the main chassis b, and has a substantially spiral cam groove n formed on its upper surface. The tip of a pin o protruding downward from the movable body h is slidably engaged with the cam groove n of the cam gear l through an elongated hole p formed in the main chassis b.

q is a tension spring whose one end is connected to the main chassis b side and the other end is attached to the movable body h, and the movable body h is directed to the right in Fig. 6 by the tensile force of the tension spring q. Therefore, the pin o is always
It comes into contact with the side surface of the cam groove n on the side of the support shaft m, thereby synchronizing the rotation of the cam gear l and the movement of the movable body h.

r is a stepping motor having a feed gear s fixed to its rotating shaft, and the feed gear s is meshed with the cam gear l.

When the spindle c is rotated, the magnetic disk e is rotated, so that a predetermined signal is recorded on the magnetic disk e by the magnetic head i while forming a circular track. When the stepping motor r is rotated clockwise in FIG. 6, the cam gear l is rotated counterclockwise, so that the pin o is pressed toward the left by the cam groove n, and Therefore, the moving body h is moved to the left. On the other hand, stepping motor r
When is rotated counterclockwise, the cam gear l is rotated clockwise, and the movable body h is moved to the right.

(Problem to be solved by the invention D) As described above, in the conventional magnetic disk drive device a, two guide shafts j and k are used to guide the moving direction of the moving body h that supports the magnetic head i. However, in such a guide means, in order to keep the attitude of the moving body h with respect to the magnetic disk e as constant as possible, the length of the moving body h, that is, the guide axis j, The length between the two positions supported by k should be made as long as possible, or the machining accuracy of guide shafts j and k and the moving body h should be
It is necessary to increase the machining accuracy of the parts supported by the guide shafts j, k, that is, the insertion holes, as much as possible, thereby reducing the clearance between the guide shafts j, k and the insertion holes.

However, even in the conventional magnetic disk drive device a, the moving body h has a considerable length, and recently, this type of device is required to be as small as possible. , it is extremely difficult to increase the length of the moving body h any further.

In addition, even if the machining accuracy of the guide shafts j, k and the insertion holes of the moving body f is improved, there is a certain limit to the accuracy of such machining, and if you are forced to do so, the machining accuracy will be reduced. The increased processing cost increases, which ultimately increases the cost of the device a.

(E. Means for Solving Problems) In order to solve the above-mentioned problems, the rotary recording medium drive device of the present invention has a movable body slidably supported on a guide shaft supported by a chassis. A pin part provided on the movable body is slidably engaged with a cam groove formed in a cam gear rotated by a rotating means, the tip part is attached to the movable body, and the base end is fixed to the chassis. At the same time, an arm with spring elasticity is provided in the middle part of the arm with a margin that is elastically displaced as the movable body moves, and the movable body has its pin portion pressed against the inner circumferential surface of the cam groove by the arm. In this state, the cam gear slides on the guide shaft as the cam gear rotates.

Therefore, according to the present invention, since the movable body is biased by the elastic force by the arm, the movable body is always kept in a constant posture, and the movable body is moved along the guide means in this state. Therefore, it is moved in a state in which it is always held in a constant posture, that is, in a state in which its orientation with respect to the rotary recording medium does not change when it is moved. Moreover, its structure becomes extremely simple.

(F. Embodiment) Details of the rotary recording medium drive device of the present invention will be described below with reference to embodiments shown in the accompanying drawings.

In the embodiment shown in the drawings, the present invention is applied to a magnetic disk drive device 1.

(a Spindle mechanism) [Figures 1 and 2] 2 is a spindle mechanism provided approximately at the center of the upper surface of the chassis 3, and the spindle mechanism 2 includes a support shaft fixed to the chassis 3 and the support shaft. It consists of a spindle rotatably supported by a spindle and a spindle motor that rotates the spindle.

4 is a support shaft. The support shaft 4 has a lower end portion fixed to the chassis 3, and is provided so as to pass through the chassis 3 in the thickness direction thereof.

5 is a spindle motor, and the spindle motor 5 has a stator 6 fixed to the chassis 3 side.
and a rotor 7 disposed opposite to the stator 6 and rotatably supported by the support shaft 4.

Reference numeral 8 designates a spindle fixed to the upper surface of the rotor 7 of the spindle motor 5, which includes a disk portion 8a having approximately the same size as the rotor 7, and a generally provided disk portion 8a protruding upward from the center of the disk portion 8a. and a cylindrical engagement shaft 8b, and the support shaft 4 is attached to the engagement shaft 8b.
The upper end of is inserted. Reference numeral 9 denotes a roughly ring-shaped chuck magnet provided on the upper surface of the disc portion 8a.

Thus, when the spindle motor 5 rotates, the spindle 8 is rotated together with it.

(b Moving body, guide shaft) [Figures 1 to 3] 10 is a moving body that supports the magnetic head. The movable body 10 is formed into a substantially block shape that is elongated in the left-right direction, and has a head mounting piece 11 fixed to its upper surface, and a magnetic head 12 mounted to the upper surface of the head mounting surface 11.

Reference numeral 13 denotes a hole formed to pass through the axial center of the movable body 10 in the left-right direction in FIG. 1, and a bearing member 14 made of so-called sintered metal is fixed in the hole 13.

15 is from the rear surface of the moving body 10 (the downward direction in FIG. 1 is defined as the front side, and the upward direction is defined as the rear side. In the following explanation, directions will be referred to in this direction) to the rear. The movable body 10 is attached to the tip of an arm, which will be described later, via this attachment piece.

Reference numeral 16 denotes a pressed pin that is provided so as to protrude downward from a position slightly to the left of the position directly below the portion where the magnetic head 12 is supported on the lower surface of the moving body 10.

Incidentally, the spindle motor 5 of the chassis 3
A long hole 17 that is long in the left-right direction is formed in a portion from a position slightly to the right side to a substantially intermediate portion between the position and the right edge of the chassis 3.

Reference numeral 18 denotes a guide shaft for slidably supporting the movable body 10 and guiding the moving direction of the movable body 10, and the guide shaft 18 is provided so that its axial direction extends along the left-right direction. , is located to the right of the center of the spindle 8, and its both ends are separately connected to a support member 19 located close to the right side of the spindle 8 and a support member 20 provided near the right edge of the chassis 3. Supported.

A guide shaft 18 is inserted through the bearing member 14 provided on the movable body 10.

Thus, the moving body 10 is supported by the guide shaft 18 so as to be movable in the left-right direction. Therefore, the magnetic head 12 supported by the moving body 10 moves along a line extending in the left-right direction through the center of the spindle 8. will be done.

Note that the lower part of the pressed pin 16 protruding downward from the movable body 10 is positioned on the lower surface side of the chassis 3 through the elongated hole 17 formed in the chassis 3.

(c Arm) [FIGS. 1 and 3] Reference numeral 21 denotes an arm for applying a predetermined elastic force to the moving body 10.

The arm 21 is made of, for example, a plate spring material and is formed into a wide, generally band-like shape, and a substantially intermediate portion 22 (hereinafter referred to as the "marginal portion") in the longitudinal direction is oriented in the thickness direction of the arm 21. It is bent into a roughly semicircular arc shape that protrudes from the top. Therefore, arm 2
1 is that when one end 21a in the longitudinal direction is fixed and the other end 21b is pulled toward the opposite end, the shape of the margin 22 is deformed so that the curvature of its arc increases. , and in the above-described state, the other end 21b
When the one end portion 21a is pressed, the margin portion 22
The shape of is deformed so that the curvature of its arc becomes smaller, thereby being shortened.

That is, the arm 21 has a shape that can be expanded and contracted in the longitudinal direction by deforming the shape of the margin portion 22.

Reference numeral 23 denotes an arm mounting member provided at a position further toward the rear edge from a substantially intermediate portion between the rear edge of the chassis 3 and the guide shaft 18.

The arm 21 has one end 21a fixed to the arm mounting member 23 by a fixing means such as a screw, with its side surface facing substantially in the left-right direction, and the other end 21b fixed to the moving body 1.
It is fixed to a mounting piece 15 protruding from 0 by fixing means such as screws.

Therefore, the arm 21 is fixed to the movable member 23 approximately in the front-rear direction, and the other end 21b
When the is fixed to the movable body 10, one end 21a is applied with an elastic force that tends to move approximately to the left, and the other end 21b is applied with an elastic force that attempts to move approximately to the right. This means that the elastic force that

Therefore, the movable body 10 is affected by the elastic rotational force of the arm 21, that is, the one end 21a of the arm 21.
A rotational force in the counterclockwise direction in FIG. 1 with rotation center at is applied.

Note that the effect of the rotational force applied to the moving body 10 in this manner will be described later.

(d Cam gear) [Fig. 1, Fig. 2, Fig. 4] 24 is a cam gear. The cam gear 24 has an outer shape substantially in the shape of a so-called flat gear, and has a diameter that is approximately the same as the diameter of a magnetic disk, which will be described later, and has a bearing member 25 fixed to its center.

26 is a cam groove formed on the upper surface of the cam gear 24, and the cam groove 26 is formed in a spiral shape. Incidentally, the difference between the distance from the center of the cam groove gear 24 at a position near one end of the cam groove 26 and the distance from the center of the cam gear 24 at a position near the other end of the cam groove 26 is determined by the movement required for the magnetic head 12. The distance is approximately the same as the stroke.

The cam gear 24 is rotatably supported by the support shaft 4 on the lower surface side of the chassis 3 by inserting a portion of the support shaft 4 that projects downward from the chassis 3 into the bearing member 25 .
A washer 27 is engaged with a portion of the support shaft 4 that projects downward from the cam gear 24, and the washer 27 prevents the cam gear 24 from coming off the support shaft 4.

Thus, the cam gear 24 is arranged coaxially with the axis of the spindle 8.

Further, a lower end portion of the pressed pin 16 protruding downward from the movable body 10 is slidably engaged with a cam groove 26 formed in the cam gear 24.

As described above, since the movable body 10 is elastically biased with a rotational force that tends to move it approximately to the right, the pressed pin 16 is always pressed between the two cam grooves 26. It is pressed against the inner peripheral surface located on the side opposite to the support shaft 4 among the inner peripheral surfaces.

Therefore, when the cam gear 24 is rotated counterclockwise, the portion of the cam groove 26 on the right side of the spindle 8 is gradually displaced toward the spindle 8, so that the pressed pin 16 is pressed toward the left side. That will happen. Therefore, the moving body 10 is moved toward the left side. Conversely, when the cam gear 24 is rotated clockwise, the cam groove 2
6, the part on the right side of the spindle 8 gradually moves away from the spindle 8, so the moving body 1
0 will be moved to the right by the elastic force of the arm 21.

(e. Maintaining the Attitude of the Moving Body) The attitude of the moving body 10 is maintained as follows by the elastic turning force urged by the arm 21.

That is, the moving body 10 is provided with the first
Since the rotational force in the counterclockwise direction in the figure is applied, the pressed pin 16 protruding from the movable body 10 is moved toward the opposite side of the support shaft 4 of the cam groove 26 of the cam gear 24, as described above. It will be pressed against the inner peripheral surface.

Therefore, in this state, the moving body 10 is prevented from rotating in the clockwise direction by the counterclockwise pressing force urged by the arm 21, and is prevented from rotating in the counterclockwise direction. This movement is prevented by the pressed pin 16 coming into contact with the inner peripheral surface of the cam groove 26.

For example, when the movable body 10 is moved to the left from the state shown in FIG. As shown by the two-dot chain line in the figure, the arc is deformed so that its curvature increases (the amount of deformation is exaggerated in the drawing), and its length increases. The direction of the other end 21b of the arm 21 does not change when the arm 21 is rotated.

Further, when the movable body 10 is moved to the right from the state shown in FIG. 1, the arm 21 is rotated counterclockwise.
1's margin 22 is deformed to increase its curvature and its length is extended, so that the other end 21b of the arm 21 changes in direction when the arm 21 is rotated. Never.

In this way, the posture of the moving body 10 is always maintained constant.

Therefore, if the posture of the movable body 10 in a state in which the pressed pin 16 is in contact with the inner circumferential surface of the cam groove 26 is precisely adjusted, the movable body 10 will always be in the correct position that has been adjusted based on its accuracy. It will be held in position.

Although not shown, the support members 19 and 20 on which the guide shaft 18 is supported and the arm mounting member 2
The position of the third and other parts in the horizontal and/or vertical directions relative to the mechanical chassis 3 can be finely adjusted, and the attitude of the moving body 10 can be adjusted by adjusting the position of these adjustment members. It's getting old.

Also, when the arm 21 is rotated, the margin 2
According to an example of the experimental results of measuring the amount of extension of arm 21, the length of arm 21 is approximately 30 mm, and even when moving body 10 is moved approximately 5 mm,
The margin portion 22 was expanded by approximately 0.1 mm.

(f feed gear, motor) [Figures 1 and 2] 28 is a motor provided on the bottom side of the chassis 3, and the output shaft 29 of the motor 28 is connected to the feed gear 3.
0 is fixed, and the feed gear 30 has gear teeth 24a, 2 formed on the outer peripheral surface of the cam gear 24.
4a, ... are meshed with each other.

Note that the motor 28 is a normal motor, not a special motor such as a stepping motor that has a function of controlling its rotation angle, and its rotation is controlled by a rotary encoder (not shown) or by a rotary encoder (not shown). The cam gear 24 is controlled by a position detection signal of the cam gear 24 detected by a position detection means. Note that in order to detect the position of the cam gear 24, for example, the cam gear 2
A conceivable method is to form a large number of holes at regular intervals on the outer periphery of the hole 4, and to detect the holes with a photo sensor or the like.

Therefore, when the motor 28 is rotated clockwise, the feed gear 30 is rotated clockwise, so the cam gear 24 is rotated counterclockwise, and the motor 28 is rotated counterclockwise. When rotated in the clockwise direction, the cam gear 24 is rotated clockwise.

(g Magnetic disk cassette) [Fig. 1, Fig. 2,
FIG. 5 ] 31 is a magnetic disk cassette. Reference numeral 32 designates the cassette casing, and the cassette casing 32 is formed in the shape of a thin, approximately square box, with center holes 33 and 34 formed approximately in the center, and a portion near one edge. head window 35,
36 are formed.

A magnetic disk 37 is rotatably housed in a cassette housing 32, and has a recording surface made of a magnetic layer formed on one surface thereof, and a center core 38 fixed to its center. An engagement hole 39 is formed in the center core 38, into which the engagement shaft 8b of the spindle 8 is engaged. and,
The upper and lower surfaces of the center core 38 are covered by the cassette housing 32.
They are located in center holes 33 and 34 formed in

The shutter 40 is used to open and close the head windows 35 and 36 (FIG. 5 shows the head windows 35 and 36 in a partially open position).
0 is held in a position where the head windows 35 and 36 are closed when the magnetic disk cassette 31 is not used, and is moved to a position where the head windows 35 and 36 are opened when the magnetic disk cassette 31 is attached to the magnetic disk drive device 1. It is becoming more and more like this.

Therefore, when the head windows 35, 36 are opened, the portions of the magnetic disk 37 corresponding to the head windows 35, 36 are exposed to the outside.

(h Recording and Reading) Therefore, when recording on the magnetic disk 37 or reading the contents recorded therein, the magnetic disk cassette 31 is moved to the magnetic disk drive device 1 as shown in FIGS. Attach to.
This mounting is performed by a cassette mounting mechanism (not shown).

When the magnetic disk cassette 31 is installed in the magnetic disk drive device 1, the engagement shaft 8b of the spindle 8 is engaged with the engagement hole 39 formed in the center core 38 of the magnetic disk 37, and the center core 38 is engaged with the engagement shaft 8b of the spindle 8. A piece to be attracted made of a magnetic material (not shown) is attracted to the chuck magnet 9 provided on the disk portion 8a of the spindle 8, whereby the magnetic disk 37 rotates integrally with the spindle 8. It will be in a state where it is Also, along with this,
The magnetic head 12 is inserted into the cassette housing 32 through a head window 36 formed in the cassette housing 32.
At the same time, the gap surface is brought into contact with the recording surface of the magnetic disk 37.

When a recording or reading command is issued from this state, the spindle 8 is rotated, the magnetic disk 37 is rotated, and the predetermined recording signal supplied to the magnetic head 12 is transferred to the recording surface of the magnetic disk 37. The magnetic head 1 records the information while forming a circular track, or reads the already recorded content.
This is done through 2.

For example, when accessing the magnetic head 12 to another recording track, the motor 28 is rotated, thereby rotating the cam gear 24 by a predetermined amount necessary to transport the magnetic head 12 to the target recording track. , the moving body 10 is moved by a predetermined amount in a predetermined direction. As a result, the magnetic head 12 is moved by a predetermined amount toward the center or toward the periphery of the magnetic disk 37. In this way, preparations are made for recording or reading to the target track. Recording or reading is performed by repeating this process.

(G. Effect of the invention) As is clear from the above description, the invention supports the rotating means for rotating the rotary recording medium and the head, and is moved in a direction substantially perpendicular to the recording track of the rotary recording medium. In a rotary recording medium drive device comprising a movable body and a moving means for moving the movable body, recording or reading on a rotary recording medium is performed with a head facing the rotating rotary recording medium. The movable body is slidably supported on a guide shaft supported by the chassis, and a pin portion provided on the movable body is slidably in a cam groove formed in a cam gear that is rotated by a rotating means. The arms are engaged with each other, and have a distal end attached to the movable body and a proximal end fixed to the chassis, and an arm having spring elasticity and having a margin in the middle thereof to be elastically displaced as the movable body moves. The movable body is characterized in that its pin portion is pressed against the inner circumferential surface of the cam groove by the arm and slides on the guide shaft as the cam gear rotates. shall be.

Therefore, according to the present invention, since the movable body is given a resilient force by the arm, its posture is always maintained constant, and the movable body is moved along the guide means in this state. Therefore, it is moved in a state where it is always held in a constant posture, that is, in a state in which the orientation with respect to the rotary recording medium does not change when it is moved.

Furthermore, the only member necessary to maintain a constant posture of the moving body is an arm having spring elasticity, that is, an extremely simple member made of, for example, a leaf spring material. The weight can be sufficiently reduced, and the structure can also be made quite simple.

In the present invention, the arm that attaches the movable body is provided with a margin that can expand and contract in a direction substantially perpendicular to the moving direction of the movable body, so that the arm is rotated when the movable body is moved. Since the arm is expanded and contracted in accordance with changes in the distance between the base end of the arm and the movable body, the movement locus of the movable body is accurately determined by the guide means.

In addition, in the above-mentioned embodiment, as an arm,
I decided to use a single leaf spring, but
The form of the arm in the present invention does not necessarily have to be in the shape of a leaf spring, but rather has a spring elasticity and a margin that can expand and contract in a direction substantially perpendicular to the moving direction of the moving body. Any form may be used as long as it is possible to do so, and in some cases, it may be possible to provide a plurality of them in the height direction.

Furthermore, the present invention can be applied to various types of rotary recording medium drive devices that drive rotary recording media other than magnetic disks.

[Brief explanation of the drawing]

1 to 5 show an example of an embodiment in which the rotary recording medium drive device of the present invention is applied to a magnetic disk drive device, FIG. 1 is a plan view, and FIG. 3 is an enlarged perspective view of the main parts, FIG. 4 is a perspective view of a cam gear, FIG. 5 is a perspective view of a magnetic disk cassette, and FIG. 6 is an example of a conventional magnetic disk drive device. FIG. Explanation of symbols, 1...Rotary recording medium drive device (magnetic disk drive device), 2...Rotating means (spindle mechanism), 3... Chassis, 10... Moving body,
12...Head (magnetic head), 16, 24, 2
6, 28, 30...Moving means, 16...Pressed pin, 24...Cam gear, 26...Cam groove, 28...
...Motor, 30...Feed gear, 18...Guide shaft,
21... Arm, 22... Extra portion, 37... Rotating recording medium (magnetic disk).

Claims (1)

[Claims for Utility Model Registration] A rotating means 2 for rotating a rotary recording medium 37, a movable body 10 that supports the head 12 and is moved in a direction substantially perpendicular to the recording track of the rotary recording medium, and the movable body. Moving means 16, 24, 2
6, 28, and 30, and the rotary recording medium drive device 1 performs recording or reading on a rotary recording medium with the head facing the rotating rotary recording medium, the moving body being a chassis 3; Guide shaft 1 supported by
A pin portion 16 provided on the movable body and slidably supported by the rotating member 8 is slidably engaged with a cam groove 26 formed in a cam gear 24 that is rotated by a rotating means 28. The arm 21 is attached to the movable body and the proximal end is fixed to the chassis, and an arm 21 having spring elasticity is provided in the middle thereof with a margin 22 that is elastically displaced as the movable body moves. The rotation body is characterized in that the pin portion is pressed against the inner circumferential surface of the cam groove by the arm and slides on the guide shaft as the cam gear rotates. type recording medium drive device.