JPS63177377A - 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 two pieces of needles sandwiching a shaft to travel a mobile base, fixing the rear end part of one of the needles to the mobile base, and the rear end part of the other via a pressing spring. CONSTITUTION:The needle 9A positioned opposing to the needle 9 is brought into contact with the guide groove 8a of a shaft 8, and its rear end part is fixed on the projecting part 3d of the mobile base 3 via the pressing spring 12, also, this needle 9A is brought into contact with the guide groove 8a similarly with the needle 9. If 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 are 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 the 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/outer peripheral direction of a storage medium.

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. 4 to 8 are diagrams showing a magnetic head moving device used in a conventional flexible disk storage device. FIG. 4 is a plan view, and FIG. -V line sectional view, 6th
The figure is a sectional view taken along the line VI-VI in FIG. 4, and FIGS. 7 and 8 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). A guide rod (6) is arranged parallel to the moving direction of the magnetic head (2), and is inserted through the bearings (5a) and (5b) and fixed at both ends. (
7) is a drive motor, and (8) is a guide groove (8a) which is rotated by the drive motor (7) and whose cross section is approximately trapezoidal on the outer peripheral surface.
) is formed, and (9) is a needle whose rear end is fixed to the protrusion (3d) of the moving table (3), and is arranged parallel to the guide groove (8a) of the shaft (8). Guide groove (8a)
is in contact with. (10) is a pressure spring that is placed opposite the needle (9) with the shaft (8) in between, and whose rear end is fixed to the moving table (3), and is in constant contact with the outer peripheral surface of the shaft (8). A predetermined contact pressure is applied 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 6) Here, μ: Coefficient of friction between the guide groove (8a) and the needle (9) α: Angle of the guide groove (8a) F: Pressure force of the pressure spring (10) D: Needle (9) ) [Problems 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. 5, the movable 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 7, specifically about 0.01 mm. I at the contact point r between the groove (8a) and the needle (9)
F Frictional force generated, Fr=2Xμx7x-sxnα
2 presses the moving table (3) in the direction of arrow U. 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 Δx = HX C/L where, H: Distance between the center of the shaft (8) and the normal center point of the magnetic head (2) C: Gap between the guide rod (6) and the bearing (5a) 2 times L: Obtained from the length of the moving table (3). Now, L=40mm, H=30mm,
If C = 0.01mm, Δx = 0.0075mm
It is.

Next, when the shaft (8) rotates clockwise (in the direction of arrow B) in FIG. 5, the moving table (3) moves toward the outer circumference of the recording medium (1). At this time, as shown in Figure 8, 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 shift amount of 0.0075 m+a, a so-called patch crush 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 is provided with two needles sandwiching a shaft, one of the needles has its rear end fixed to a moving table, and the other needle has its rear end fixed to a moving table. It is fixed to the moving table via a pressure spring.

[Function] In this invention, since the two needles face and contact the guide groove of the shaft, the frictional force generated by the contact between the shaft and the needle changes the state of contact between the moving table and the guide rod. By holding the stand in the same state regardless of the moving direction, backlash during magnetic head positioning is reduced.

[Example] Figures 1 to 3 are diagrams showing an example of the present invention.
The figure is a plan view, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line ■-■ in FIG.

In the figure, (9A) is a shaft (8) arranged opposite to the needle (9).
), and its rear end is in contact with the guide groove (8a) of the pressure spring (12
) The pressure spring (10) of the conventional device is in contact with the outer circumferential surface of the shaft (8) with the needle fixed to the protrusion (3d) of the moving table (3) via the needle, but in this implementation The example is
A needle (9A) fixed to the pressure spring (12) is in contact with the guide groove (8a) like 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 indicated by the arrow in Fig. 2, the guide groove (8a) and the needle (9) (9
Since the frictional force with A) is the same but in a different direction, no force is generated that acts in the normal direction to the axial direction of the guide rod (6), and the shaft (8) rotates in the direction of arrow B. In this case, the above frictional force is as shown by the broken line in Fig. 2, as in the case of the direction indicated by the arrow.

No force is generated that 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), that is, when the movable stage (3) moves to a predetermined track of the recording medium (1) from the inner circumferential direction or from the outer circumferential direction, the magnetic head (2) is It can be stopped at the same position.

[Effects of the Invention] As explained above, in this invention, two needles are provided that sandwich the shaft for moving the moving table, one of the needles has its rear end fixed to the moving table, and the other needle has its rear end fixed to the pressing spring. Since the magnetic head is fixed to the movable table via the magnetic head, it is possible to significantly reduce backlash caused by the direction of rotation of the drive motor, and to position the magnetic head with high precision.

[Brief explanation of the drawing]

1 to 3 are diagrams showing an embodiment of a magnetic head moving device according to the present invention, in which FIG. 1 is a plan view, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. Cross-sectional view along the ■-■ line in Figure 1,
4 to 8 are diagrams showing a conventional magnetic head moving device, in which FIG. 4 is a plan view, FIG. 5 is a sectional view taken along the line ■-V in FIG. 4, and FIG. The VI-VI line sectional view, FIGS. 7 and 8 are explanatory diagrams 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 rod, (9) (9A) is a needle, and (12) is a pressure spring. 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 shaft, and two needles provided on the movable table and arranged with the shaft in between and in contact with the guide groove; one of the needles has its rear end fixed to the movable table; The other is a magnetic head moving device whose rear end is fixed to the moving table via a pressure spring. (2) Claim 1 in which the shaft is arranged parallel to the guide rod
2. The magnetic head moving device described in .