JPS63177378A - Magnetic head traveling device - Google Patents

Abstract

PURPOSE:To reduce backlashes generated by the direction of rotation of a driving motor and to highly accurately position a magnetic head by providing needle sandwiching a shaft to travel a mobile base and a pressing spring, and fixing the rear end of the needles on the mobile base and the pressing spring also on the mobile base. CONSTITUTION:A projecting strip 10a brought into contact with the guide groove 8a of the shaft 8 disposed so as to oppose to the needle 9, is formed, and the rear end of this strip 10a of the pressing spring 10 fixed on the projecting part 3d of the mobile base 3 is brought into contact with the guide groove 8a in a similar manner as the needle 9. When the shaft 8 rotates in the direction of arrow A, the friction force between the groove 8a and the needle 9, and that between the groove 8a and the needle 9A and equal and in the opposite directions, therefore, no force acting in the direction of the normal of the shaft of a guide bar 6 occurs. Also, when the shaft 8 rotates in the direction of arrow B such as the case of the rotation in the direction of arrow A, no force that acts in the direction of the normal of the shaft of a guide bar 6 occurs, hence the magnetic head 2 can be stopped at one and the same place even when the mobile base 3 travels from the inner/output peripheral part of a storage medium to the respective opposite directions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a magnetic head moving device in a flexible disk storage device or the like.

[Prior Art] FIGS. 5 to 9 are diagrams showing a magnetic head moving device used in a conventional flexible disk storage device, in which FIG. 5 is a plan view and FIG. 6 is a VI of FIG. -VI line sectional view,
FIG. 7 is a sectional view taken along the line ■--■ in FIG. 5, and FIGS. 8 and 9 are explanatory diagrams of the behavior of the moving table.

In the figure, (1) is a recording medium on which information signals are recorded, and is made of a flexible disk whose surface is made of a magnetic medium. (
2) is a magnetic head that records an information signal consisting of an electric signal as a magnetic signal on the recording medium (1) or reproduces an information signal consisting of a magnetic signal recorded on the recording medium (1) as an electric signal; 3) is a moving table that holds the magnetic head (2), and is mainly made of engineering plastic material by precision injection molding, etc., and is protruded from the substrate (3a) in a direction perpendicular to the direction of movement of the magnetic head (2). (5a) (5b) is attached to the guided part (
3b) It has (3c) and a protruding part (3d) protruding on the opposite side of the guided part (3c). (6) is a guide rod arranged parallel to the moving direction of the magnetic head (2), which is inserted through the bearings (5a) and (5b) and fixed at both ends.

(7) is a drive motor, and (8) is a guide groove (8) rotated by the drive motor (7) and having a substantially trapezoidal cross section on the outer peripheral surface.
The shaft on which a) is formed, the rear end of (9) is the movable table (3)
The needle is fixed to the protrusion (3d) of the shaft (8) and is arranged parallel to the guide groove (8a) of the shaft (8).
) is in contact with. (10) is placed opposite the needle (9) with the shaft (8) in between, and its rear end is the movable table (3).
A pressure spring fixed to the shaft (8) is in contact with the outer peripheral surface of the shaft (8) to constantly apply a predetermined contact pressure between the guide groove (8a) and the needle (9).

A conventional magnetic head moving device is configured as described above, and when moving the magnetic head (2) to a predetermined position on the recording medium (1), the drive motor (7) is driven in a manner corresponding to the amount of movement of the magnetic head (2). Rotate the displacement angle. As the drive motor (7) rotates, the shaft (8) rotates and the needle (9) moves along the shaft (8). At this time, since contact pressure is applied between the guide groove (8a) and the needle (9) by the pressure spring (10), the guide groove (8a) and the needle (9)
is in sliding contact with the guide groove (8a).
This prevents the generation of noise due to poor contact between the guide groove (8a) and the needle (9), and prevents the needle (9) from moving over the peak of the guide groove (8a) to the adjacent valley.

In this way, when the needle (9) moves, the moving table (3) moves guided by the guide rod (6). As a result, the magnetic head (2) moves to a predetermined position on the recording medium (1).

Here, the drive motor (
The load torque T for 7) is given by the following equation (2). (See Figure 7) Here, μ: Coefficient of friction between the guide groove (8th) and the needle (9) α: Angle of the guide groove (8a) F: Pressure force of the pressure spring (10) D: Needle ( 9) Contact diameter [Problem to be solved by the invention] In the conventional magnetic head moving device as described above, the pressing force F is applied by the pressing spring (10), and the load torque T is 0.
It is shown by the formula. As is clear from equation 0, this load torque T is calculated by the following four factors: friction coefficient μ, angle α, pressing force F, and contact diameter.
Although determined by variables, the angle α, the pressing force F, and the contact diameter are based on the fact that the shape of the recording medium (1) is standardized and the magnetic head (2) relative to the center of rotation of the recording medium (1). Since accurate and high positioning accuracy is required, there is a limit to its value, and it is difficult to reduce the load torque T by changing these variables. Furthermore, it is impossible to significantly improve the friction coefficient μ in the case where the needle (9) is brought into sliding contact with the guide groove (8a) as described above.

Now, when the shaft (8) rotates counterclockwise (in the direction of the arrow) in FIG. 6, the moving table (3) moves toward the inner circumference of the recording medium (1). At this time, it is inevitable that there will be a slight gap between the bearings (5a) (5b) and the guide rod (6), as shown in Figure 8, specifically about 0.01 mm. The movable table (3) is pressed in the direction of arrow U at the contact point r between the groove (8a) and the needle (9). As a result, the guide rod (6) and the bearings (5a) (5b) come into contact at points q and r, respectively, and the center E of the magnetic head (2) is shifted from the normal position by ΔX. This amount of deviation ΔX is
Δz=HXC/L Where, H: Distance between the center of the shaft (8) and the normal center point of the magnetic head (2) C: Twice the gap between the guide rod (6) and the bearing (5a) L: Moving table It is determined by the length in (3). Now, L=40mm, H=30mm,
If C==0.01mm, Δx =0.0075
It is mm.

Next, when the shaft (8) rotates clockwise (in the direction of arrow B) in FIG. 6, the moving table (3) moves toward the outer circumference of the recording medium (1). At this time, as shown in Figure 9, move the moving platform (
3) A frictional force Fr in the direction opposite to the direction of arrow U acts,
Guide rod (6) and bearings (5a) (5b) are at point p and point S
contact each other. As a result, it will be easily understood that the magnetic head (2) deviates from the normal position by ΔX.

In this way, the magnetic head (2) held by the moving table (3) is positioned at a predetermined position on the recording medium (1) by giving a predetermined angular displacement to the shaft (8) of the drive motor (7). In this specific example, depending on the direction of rotation of the shaft (8), ±
This results in a deviation amount of 0.0075 mm, a so-called backlash amount, which poses a problem in that highly accurate positioning is hindered.

This invention was made to solve the above problems, and is a magnetic head moving device that reduces the frictional force generated at the point of contact between the guide groove of the shaft and the needle, thereby making it possible to position the magnetic head with even higher precision. The purpose is to provide

[Means for Solving the Problems] A magnetic head moving device according to the present invention includes a needle fixed to a moving table and in contact with a guide groove of the shaft, and a needle fixed to the moving table and extending in the direction of the shaft. A pressurizing spring is provided on the extending portion facing the shaft and having a protrusion that comes into contact with the guide groove of the shaft.

[Function] In this invention, since the protrusions of the needle and the pressure spring are opposed to and in contact with the guide groove of the shaft, the frictional force generated by this contact changes the state of contact between the movable table and the guide rod. By holding the movable table in the same state regardless of the moving direction, backlash during positioning of the magnetic head is reduced.

[Example] Figures 1 to 4 are diagrams showing an example of the present invention.
The figure is a plan view, Figure 2 is a sectional view taken along the line ■-■ in Figure 1, Figure 3 is a left side view of Figure 2, and Figure 4 is a sectional view taken along the line IV-IV in Figure 1. Parts that are the same as the device are designated by the same reference numerals.

In the figure, (10) is arranged opposite to the needle (9) and the shaft (8)
) is formed with a protrusion (10a) that contacts the guide groove (8a), and the rear end is a pressure spring fixed to the protrusion (3d) of the moving table (3), which is different from the pressure spring (10) of the conventional device. ) is in contact with the outer peripheral surface of the shaft (8), whereas in this example,
A protrusion (10a) formed on the pressure spring (10) is in contact with the guide groove (8a) similarly to the needle (9).

In the magnetic head moving device configured as described above, the movable table (3) is moved by rotation of the shaft (8), as in the conventional device. When the shaft (8) rotates in the direction of arrow A in FIG. (6) No force acting in the normal direction to the axial direction is generated, and when the shaft (8) rotates in the direction of arrow B, the above frictional force is as shown by the broken line in FIG. As in the case of direction, no force is generated which acts in the direction normal to the axial direction of the guide rod (6). Therefore, depending on the direction of rotation of the shaft (8), i.e. the movement stage (3)
The magnetic head (
2) can be stopped at the same position.

[Effects of the Invention] As explained above, in this invention, a needle and a pressure spring are provided which sandwich the shaft for moving the moving table, the rear end of the needle is fixed to the moving table, and the pressure spring is provided with a pressure spring in the guide groove of the shaft. Since the contacting protrusion is provided and the rear end is fixed to the movable table, backlash caused by the rotational direction of the drive motor can be significantly reduced and the magnetic head can be positioned with high precision.

[Brief explanation of the drawing]

1 to 4 are views showing one embodiment of a magnetic head moving device according to the present invention, in which FIG. 1 is a plan view, FIG. 2 is a cross-sectional view taken along line u-n in FIG. 1, and FIG. 2 is a left side view, FIG. 4 is a sectional view taken along the line ■-IV in FIG. 1, FIGS. 5 to 9 are views showing a conventional magnetic head moving device, and FIG. Figure 6 is a sectional view taken along the line ■-■ in Figure 5, and Figure 7 is a cross-sectional view taken along the line ■-■ in Figure 5.
(2) Line sectional view, FIGS. 8 and 9 are explanatory views of the behavior of the moving table. In the figure, (2) is a magnetic head, (3) is a moving table, (6) is a guide rod, (7) is a drive motor, (8) is a shaft, (8a) is a guide groove, (9) is a needle, (10) is a pressure spring, (1
0a) is a protrusion. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A moving table with a magnetic head attached thereto and slidably attached to a guide rod arranged parallel to the moving direction of the magnetic head, and a moving table rotated by a drive motor to form a spiral guide groove on the outer peripheral surface. a needle having a rear end fixed to the movable table, extending in the direction of the shaft and contacting the guide groove;
A pressurizer whose rear end is fixed to the movable table, extends in the direction of the axis, faces the needle and is disposed across the axis, and has a protrusion on the extending portion that contacts the guide groove. A magnetic head moving device comprising a spring. (2) Claim 1 in which the shaft is arranged parallel to the guide rod
The magnetic head moving device described in .