JPH0668888B2 - Magnetic head feeder for magnetic recording / reproducing apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic head feeding device that performs recording / reproduction on a rotating magnetic sheet.

“Prior art and its problems” Various types of devices that magnetically record information on a rotating magnetic sheet (floppy disk) and reproduce it have been put to practical use. Regarding cameras, electronic cameras that magnetically record video signals are used. It corresponds to this magnetic recording (reproducing) device. In such a magnetic recording / reproducing apparatus, in order to move the magnetic head onto a predetermined track of the rotating magnetic sheet, the rotational movement of the step motor is converted into the linear movement of the carriage supporting the magnetic head. As a type of this motion converting mechanism, conventionally, a device using a feed screw and a needle shown in FIGS. 4 and 5 has been used.

The magnetic head 11 is fixed to a carriage 12, and the carriage 12 is guided by the left and right guide rails 13 and 13 in a direction parallel to the radial direction (x direction) of the rotating magnetic sheet 14, and in the y and z directions. The movement is regulated. 15
Is a spindle motor that rotationally drives the rotating magnetic sheet 14.

The feed screw 16 parallel to the guide rail 13 is located between the left and right guide rails 13, 13 and receives rotation of the step motor 18 via the coupling 17. The screw portion 16n of the feed screw 16 is located between the guide walls 12a in the front and rear of the carriage 12.

On the carriage 12, a needle 20 located between the threads of the threaded portion 16n is supported. This needle 20
A needle block 21 that straddles the threaded portion 16n has its both ends fixed.
The plate spring 23 is fixed to the center of the plate spring 23 through the.
The leaf spring 23 has its front and rear ends fixed to the guide wall 12a of the carriage 12 via fixing screws 24. As a result, the elasticity of the leaf spring 23 causes the needle 20 to be urged in the axial direction of the axis 18. The needle 20 and the threaded portion 16n are engaged with each other in the radial direction of the feed screw 16 in the axial direction without play. Reference numeral 25 denotes a compression spring, which causes the carriage 12 to generate a moment about the engagement point between the threaded portion 16n and the needle 20, thereby causing the carriage 12 to move.
The radial play between the guide rail 13 and the guide rail 13 is removed.

In the magnetic head feeding device having the above configuration, when the step motor 18 is driven, the feed screw 16 rotates according to the step angle of the step motor 18. Then, the carriage 12 engaged with the screw portion 16n and the needle 20 moves in the radial direction of the rotating magnetic sheet 14 according to the lead angle of the screw portion 16n, and thus the rotating magnetic sheet 14 rotated by the spindle motor 15.
On the other hand, the magnetic head 11 can record at a track pitch corresponding to the step angle of the step motor 18.

However, in this conventional device, since the needle 20 is fixed to the leaf spring 23 via the needle block 21, the leaf spring 23
A constant distance e is generated between the center of the plate thickness and the axis of the needle 20. Therefore, in the conventional apparatus, when the carriage 12 is moved by the step motor 18, the leaf spring 23 is bent, and this bending changes the position of the carriage 12, that is, the position of the magnetic head 11, and the track position is incorrect. There was a problem of becoming.

FIG. 6 is a model diagram for explaining this bending. Leaf spring 23
Since its front and rear ends are fixed to the carriage 12 by fixing screws 24, it corresponds to a leaf spring fixed at both ends. The hatching in the figure shows this fixed end, the one-dot chain line shows the shape of the leaf spring 23 before deformation, and the solid line shows the shape of the leaf spring 23 after being deformed by receiving the load P on the needle 20. Leaf spring in this figure
In order to formulate the deflection y at any position x of 23,
Considering the x and y coordinates with the one end fixed part of the leaf spring 23 as the origin,
The longitudinal elastic modulus of the leaf spring 23 is E, the second moment of area is I,
The length is d, the width is b, the thickness is h, the load is P, the moment is M, and the distance from the center of the leaf spring 23 to the axis of the needle 20 is e.
When, the deflection ^{y y = - (Mx 2 /} 2EI) (x / 2d-1/4) (0 ≦ x ≦ d /
2) Deflection angle θ is dy / dx =-(Mx / 4EI) (3x / d-1) (0 ≦ x ≦ d /
The theta in 2) x = d / 2, θ = -Md / 16EI movement amount .delta.1 of the carriage 12 due to the deflection than this, δ1 = - (given by ^{Pde 2 / 16EI) I = bh} 3/12.

Here, P = -0.05 kgf, d = 15 mm, b = 6 mm, h =
If 0.2mm, E = 19000kgf / mm ² , e = 4mm, δ1 = 1
It becomes 0 μm, which is a non-negligible amount in this type of magnetic head feeding device.

That is, the position of the recording track is displaced during recording, and it is difficult to accurately track on the track recorded at the correct position during reproduction, and the effective reproduction track width is reduced. Deteriorates the S / N ratio.

"Object of the Invention" The present invention solves the above problems of the conventional magnetic head feeding device, and in the magnetic head feeding device for moving and urging the needle on the carriage side to the feed screw side by the leaf spring, An object of the present invention is to obtain a feeder capable of eliminating the movement of the carriage (magnetic head) due to bending.

SUMMARY OF THE INVENTION The present invention is based on the above analysis that the problem with the conventional device is that there is a distance between the axial center of the needle and the plate thickness center of the plate spring. It is characterized by having been lost.

"Examples of the Invention" The present invention will be described below with reference to illustrated examples. FIGS. 1 and 2 show an embodiment of the present invention. The difference of the present invention from the conventional device is that the axial center of the needle 20 and the plate thickness center of the leaf spring 30 supporting the needle 20 are aligned. In point. The other points are the same as those of the conventional apparatus, and the same portions are denoted by the same reference numerals. The leaf spring 30 is divided into two pieces located on the left and right sides of the feed screw 16, and at the facing portion on the feed screw 16 side, thick-walled cylindrical fixing portions 31, 31 for fixing the needle 20 are formed. . A fixing screw 32 fixes the leaf spring 30 on the carriage 12.

This device with the above configuration uses the step motor 18 to feed the screw.
When 16 is rotated, the carriage 12 is moved by the engagement of the threaded portion 16n and the needle 20, as in the conventional device. At this time, the load P in the moving direction of the needle 20 is applied to the leaf spring 30 supporting the needle 20, but this load P is applied in the longitudinal direction of the leaf spring 30 within the thickness thereof.
The deformation generated in the leaf spring 30 is a strain due to compression and can be ignored. That is, the leaf spring 30 does not bend in a direction orthogonal to its plane. Therefore, the position of the carriage 12 will not be misaligned.

FIG. 3 is a model diagram corresponding to FIG. 6 showing a load P applied to the leaf spring 30. Since the load P is applied in the plane of the leaf spring 30, the strain δ2 generated in the leaf spring 30 in the moving direction of the carriage 12 is E, the width b, the thickness h, the longitudinal elastic modulus of the leaf spring 30, If the length is d, then δ2 = Pd / 4bhE. In this formula, the numerical values used in the concrete example of the calculation of the deflection in the conventional device, that is, P = -0.05 kgf, d = 15 mm, b
= 6mm, h = 0.2mm, E = 19000kgf / mm ²
δ2 = 0 μm. That is, according to the present invention, the leaf spring
The movement of the carriage 12 due to the compressive strain of 30 does not occur.

The axial center of the needle 20 and the plate thickness center of the leaf spring 23 are preferably theoretically exactly the same as described above, but in the actual configuration, due to the strain (and bending) generated in the leaf spring 30, There is no problem even if the centers of the carriage 12 and the carriage 12 are deviated to the extent that no error occurs in the track position. In the claims, this means that the axial center position of the needle 20 and the plate thickness center of the plate spring 23 are "substantially" aligned.

In an electronic camera, a magnetic head feeding device dedicated to recording is provided on the camera side, and a reproducing device is usually provided separately. However, the “magnetic recording / reproducing device” according to the present invention is a device that performs only one of recording and reproducing. including.

[Advantages of the Invention] As described above, according to the present invention, in a magnetic head feeding device that presses a carriage-side needle having a magnetic head against a feed screw rotated by a motor through a leaf spring, the axis of the needle is Since the plate spring and the plate thickness center of the plate spring are substantially aligned with each other, the plate spring is not bent and the position of the magnetic head is not deviated during the feeding operation of the carriage by the feed screw. Therefore, magnetic recording can be performed at the correct position on the rotating magnetic sheet, and on-track can be correctly performed on the recording track at the time of reproduction, so that a reproduction signal with a high S / N ratio can be obtained without lowering the reproduction signal. it can.

[Brief description of drawings]

FIG. 1 is a perspective view of essential parts showing an embodiment of a magnetic head feeding device according to the present invention, FIG. 2 is a side view of the same, and FIG. 3 is a model diagram showing a force relationship in the configuration of FIG. Figure, fifth
FIG. 6 and FIG. 6 are a perspective view, a side view, and a model view of a conventional magnetic head feeding device corresponding to FIG. 1, FIG. 2, and FIG. 3, respectively. 11 …… magnetic head, 12 …… carriage, 13 …… guide rail, 14 …… rotating magnetic sheet, 15 …… spindle motor, 16 …… feed screw, 18 …… step motor, 20 …… needle, 30 …… Leaf spring, 31 …… Cylindrical fixing part, 32 …… Fixing screw.

Claims (1)

[Claims] 1. A carriage supporting a magnetic head, guide means for guiding the carriage so that the magnetic head moves in a radial direction of a rotating magnetic sheet, and a driving direction of the carriage, which is rotationally driven by a step motor. In the magnetic head feeding device of the magnetic recording / reproducing apparatus, comprising: a feed screw to be used, a needle located between screw threads of the feed screw, and a leaf spring fixed to the carriage for pressing the needle against the feed screw. A magnetic head feeding device for a magnetic recording / reproducing apparatus, wherein the axis of the needle and the plate thickness center of the plate spring are substantially aligned with each other.