JPH0785618A - Carriage transfer mechanism - Google Patents

Abstract

PURPOSE:To obtain a carriage transfer mechanism capable of facilitating the correction of tracking with a simple constitution and also accurately adjusting the position of a magnetic head, in the carriage transfer mechanism for moving the magnetic head to a concentric circular track of a recording medium such as a magnetic disk, etc. CONSTITUTION:A pin gear 1 is rotated with the rotation of a head feeding rotary plate 3, and two pins 1a, 1b are alternately engaged with U-shaped tooth grooves of a cylindrical main gear 2. By this arrangement, the main gear 2 is rotated and moved while taking the movement according to characteristic of a sine curve or cycloid curve. The rotation of the main gear 2 is transmitted to a driving transmission cam 5 through reduction gears 4a, 4b and a gear 4c, and the carriage 8 whereon the magnetic head is fixed, is moved in accordance with the rotation of the cam 5. The carriage is displaced with the characteristic similar to the sine or cycloid curve against the rotating angle of the pin gear, then the continuous and minute movement is attained in each recording and reproducing track of the magnetic disk.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus such as a magnetic disk apparatus for recording or reproducing, and more particularly to a carriage transfer mechanism for positioning a magnetic head of the apparatus on a track.

[0002]

2. Description of the Related Art Conventionally, a magnetic disk has been used as a recording medium for computer equipment such as a personal computer, and recently has also been adopted as a recording medium for electronic still cameras and the like. With the miniaturization of each of these magnetic disks, it is required that the magnetic disk as a recording medium be also miniaturized and have a high recording density. Due to the miniaturization of the magnetic disk, the distance between the recording and reproducing tracks becomes small, and the moving mechanism of the magnetic head for recording or reproducing on each track requires highly accurate position control. Therefore, the structure is complicated and tends to be large.

Therefore, a technique has been proposed in which a magnetic head for recording and reproducing is positioned on each track by moving a carriage using a cam. FIG. 5 shows a typical example. This mechanism is mainly composed of a cam 12 whose peripheral surface is composed of a plurality of stepped flat surfaces, and a carriage 13 which moves the head, and a part of the carriage 13 is always in contact with the stepped cam surface 12a. When the cam 12 rotates, the carriage 13 moves along the stepped cam surface 12a, and the rotation angle of the cam and the displacement of the carriage form a stepped trajectory as shown in FIG. Therefore, when the displacement of the carriage becomes 0, the magnetic head fixed to the carriage is on each recording or reproducing track (just above the track).
The cam surface 12a on the stairs is formed so as to be positioned at.

[0004]

However, in the above-mentioned prior art, since the carriage is moved by the cam surface on the stairs, the movement of the magnetic head to each track is intermittent and discontinuous. Therefore, the position adjustment of the head depends on the machining accuracy or the mounting accuracy of the cam, which makes it difficult to correct the tracking. An object of the present invention is to solve the above-mentioned problem. The distance between tracks is increased as the distance from the track increases, and the speed is decreased as the position approaches the position directly above the track. It is an object of the present invention to provide a carriage transfer mechanism that realizes a mechanism for setting 0 to 0 with a simple configuration and that can adjust the position of the magnetic head with high accuracy and easily.

[0005]

In order to achieve the above-mentioned object, a carriage transfer mechanism according to the present invention is a magnetic recording medium which drives a magnetic head in a radial direction with respect to a concentric track of a magnetic recording medium to access a predetermined track. In a carriage transfer mechanism of a recording / reproducing apparatus, pins are provided at positions that are point-symmetric with respect to a rotation axis, and a disc-shaped pin gear that can be manually or electrically rotated and two pins of the rotating pin gear. A continuous curve having U-shaped tooth grooves at equal intervals so as to alternately engage with each other, having a periodicity with respect to rotation of the pin gear at a constant angle, and connecting a part of a sine curve or a cycloid curve. And a main member that is rotatably driven in both forward and reverse directions according to the amount of rotation of the pin gear, and that responds to the main member, The drive transmission cam for making a displacement for access and the magnetic head are fixed, and a part of the drive head is pressed against the outer peripheral surface of the drive transmission cam, and the magnetic recording medium is rotated according to the rotation of the drive transmission cam. And a carriage that moves in a radial direction with respect to the tracks on the concentric circles. In the vicinity of just above the track of the magnetic recording medium, the magnetic head continuously and minutely moves with respect to the rotation amount of the pin gear, and between tracks. As the magnetic head moves away from the track, the magnetic head continuously and largely moves with respect to the rotation amount of the pin gear. When a plate-shaped main rack is used as the main member, the drive moves linearly, and when a main gear is used, the drive moves rotationally.

[0006]

According to the above construction, the position of the magnetic head is controlled on each recording or reproducing track when the driving amount for the rotation of the pin gear of the main member becomes 0, and the moving amount of the magnetic head becomes minute before and after that. The position can be adjusted with high accuracy.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the drawings. FIG. 1 is a front view and a plan view showing an embodiment of a carriage transfer mechanism according to the present invention. 2 is shown in FIG.
3 is a front view and a plan view in which the vicinity of the pin gear of FIG. In each drawing, 1 is a pin gear, 2 is a main gear as a main member, 3 is a head feed rotary plate, 4a and 4b are reduction gears, 4c is a gear, 5 is a drive transmission cam, 8 is a carriage and 9 is a magnetic head. is there. The head feed rotary plate 3 has a shape in which the plane portions of two large and small cylinders 3a and 3b are overlapped on a concentric circle.
A tooth portion 3c is formed on the outer peripheral surface of b.

The pin gear 1 has a disk shape and is rotatably attached to a chassis (not shown) by a rotary shaft 6. The pin 1 is provided on one of the planes of the pin gear 1 at a point-symmetrical position (near the outer peripheral portion) about the rotary shaft 6.
a and 1b are planted. A tooth portion 1c is formed on the outer peripheral surface of the pin gear 1, and the column 3 of the head feed rotary plate 3 is formed.
It is meshed with the tooth portion 3c on the outer peripheral surface of b. Main gear 2
Has an annular shape and has a U-shaped tooth groove 2b on the inner peripheral surface.
And a tooth portion 2a is formed on the outer peripheral surface thereof. Tooth space 2b
Is the same as the distance between the pins 1a and 1b of the pin gear 1 and meshes with the pins 1a and 1b of the pin gear 1. The main gear 2 is rotatably attached to a chassis (not shown) by a roller portion of a gear retainer (not shown).
A tooth portion 2a on the outer peripheral surface of the main gear 2 is meshed with a reduction gear 4a that is a combination of two spur gears, and the reduction gear 4a is connected to a drive transmission cam 5 via a reduction gear 4b and a gear 4c. .

The drive transmission cam 5 comprises a spur gear 5a and a cam 5b having an outer peripheral surface formed of a curved surface.
Meshes with the gear 4c. The shape of the cam 5b is a curved surface that moves in one track section of the magnetic recording medium when the pin gear 1 makes a half rotation. The carriage 8 is supported by rollers on a rail provided on a chassis (not shown) so as to be movable within a range indicated by an arrow B. A pin 8a is planted at the tip of the carriage 8, and a spring (not shown) imparts a movement tendency to the left.
Therefore, the pin 8a is pressed against the outer periphery of the cam 5b of the drive transmission cam 5. The magnetic head 9 is adhesively fixed to the middle portion of the carriage 8.

Next, the operation of the mechanism shown in FIG. 1 will be described. In the figure, when the head feed rotary plate 3 is manually rotated, the pin gear 1 is rotated accordingly. When the head feed rotary plate 3 rotates 360 degrees here, the pin gear 1 rotates 180 degrees. This is because the ratio of the number of teeth of the tooth portion 1c and the number of teeth of the tooth portion 3c is 2: 1. When the pin gear 1 rotatably supported by the chassis rotates, the pins 1a and 1b alternate with each other.
The cylindrical main gear 2 rotates by meshing with the character-shaped tooth groove 2b.

FIG. 3 shows the displacement of the main gear 2 and the pin gear 1.
It is a figure showing the relationship of the rotation angle of. The vertical axis represents the displacement Δx,
The rotation angle Δθ is shown on the horizontal axis. When the displacement of the main gear 2 is approximated to a straight line in the enlarged portion of the joint between the pin gear 1 and the main gear 2, the displacement Δx draws a sine curve, and a curve like the solid line in FIG. Strictly speaking, the sine curve of FIG. 3 describes a cycloid curve. As described above, the pin gear 1
Therefore, the displacement of the main gear 2 rotated as shown in FIG.
Reduction gear 4 meshing with teeth 2a on the outer peripheral surface of main gear 2
drive transmission cam 5 that is transmitted to a and is further meshed with gear 4c
Communicate to. The drive transmission cam 5 pushes the pin 8a of the carriage 8 in contact with the curved surface of the cam 5b according to the displacement of the main gear 2. Therefore, the magnetic head 9 fixed to the carriage 8 is displaced while following the locus of the same characteristics (vertical and lateral magnifications are different) as in FIG. 3 with respect to the rotation angle of the head feed rotary plate 3.

Therefore, when the magnetic head is positioned on each recording or reproducing track of the magnetic disk at the point where the displacement of the moving amount of the magnetic head becomes the minimum, that is, at the point where it becomes 0, various misalignment occurs. Even in such a case, continuous and minute displacement is made in the rotation angle of the pin gear 1 before and after that, so that the position adjustment can be performed with high accuracy by correcting the rotation angle of the pin gear 1. In FIG. 1, the position of the magnetic head 9 is the initial position, and the head feed rotary plate 3
The drive transmission cam 5 rotates counterclockwise by the clockwise rotation of the magnetic head 9 and the magnetic head 9 moves between the tracks in the direction of the arrow A while moving in the same manner as the curve of FIG. Moving. By moving the magnetic head 9 to the 9'position, for example, tracking from 1 track to 52 tracks of a floppy disk becomes possible.

FIG. 4 is a block diagram showing another embodiment of the present invention. In this embodiment, a tooth portion 12a is provided on the outer peripheral surface of the head feed rotary plate 12, and the worm wheel 11 is attached to this.
, And the worm wheel 11 is rotated by the motor 10. The other structure is the same as that of the embodiment of FIG. In this way, it is also possible to rotate the head feed rotary plate 12 by the motor 10. In the above embodiments, the main gear is used as the main member to obtain the rotational movement amount. However, a linear main rack is used as the main member to convert the linear movement into the linear movement, and the structure is to be coupled to the reduction gear train. Is also possible.

[0014]

As described above, according to the present invention, the pin gear in which the pins are planted at the point symmetrical position about the rotation axis and the U-shaped tooth groove at the pitch between the pins are provided. A main member that is alternately engaged with the pins of the gear wheel and displaces while moving with characteristics such as a sine curve, and a drive transmission that responds to this main member and creates a displacement amount for accessing each track. The cam and the magnetic head are fixed, and the magnetic head is composed of a carriage that moves in accordance with the movement of the outer peripheral surface of the cam.
It is possible to position on each track while performing a characteristic movement such as a sine or cycloid curve, and it is possible to continuously and minutely move each time it approaches each track. Therefore, there is an effect that the position of the magnetic head can be adjusted with high accuracy with respect to the periodically circulating tracks and the magnetic head can be moved relatively quickly between the tracks.

[Brief description of drawings]

FIG. 1 is a front view and a plan view showing an embodiment of a carriage transfer mechanism according to the present invention.

FIG. 2 is a partially enlarged view of the vicinity of the pin gear in FIG.

FIG. 3 is a diagram showing a displacement characteristic of a magnetic head that is moved by the mechanism of the present invention.

FIG. 4 is a front view and a plan view showing another embodiment of the present invention.

5A and 5B are a schematic front view and a plan view showing a conventional example of a carriage transfer mechanism.

6 is a diagram showing a displacement characteristic of a magnetic head that is moved by the mechanism of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pin gear 2 ... Main gear 3 ... Head feed rotating plate 4a, 4b ... Reduction gear 4c ... Gear 5 ... Drive transmission cam 8 ... Carriage 9 ... Magnetic head 10 ... Motor 11 ... Worm wheel

Claims (1)

[Claims] 1. A carriage transfer mechanism of a magnetic recording / reproducing apparatus for driving a magnetic head in a radial direction with respect to a track on a concentric circle of a magnetic recording medium to access a predetermined track, the position being point-symmetrical about a rotation axis. Each of which is provided with a pin, has a disk-shaped pin gear that is manually or electrically rotated, and U-shaped tooth grooves that are equally spaced so as to alternately engage two pins of the rotating pin gear, It has a periodicity with respect to the rotation of the pin gear at a constant angle, and it is rotatable in both the forward and reverse directions while performing a movement such that it becomes a continuous curve by connecting a part of a sine curve or a cycloid curve. A main member that is driven according to the amount of rotation of the pin gear, a drive transmission cam that responds to the main member and creates a displacement amount for accessing each track, and a magnetic head The carriage is fixed and a part of the carriage is pressed against the outer peripheral surface of the drive transmission cam, and the carriage moves in a radial direction with respect to a concentric track of the magnetic recording medium in accordance with the rotation of the drive transmission cam. In the vicinity of the track directly above the magnetic recording medium, the magnetic head is continuously and minutely moved with respect to the rotation amount of the pin gear,
A carriage transfer mechanism characterized in that, between tracks, the magnetic head continuously and largely moves with respect to the rotation amount of the pin gear as the magnetic head moves away from the tracks.