JPS6236784A - Magnetic head feed device for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform the magnetic recording at the correct position of a rotary magnetic sheet by securing the substantial coincidence between the axial center of a needle and the thickness center of a leaf spring and therefore avoiding a position error of a magnetic head caused by the flexion of the leaf spring. CONSTITUTION:The axial center of a needle 20 is coincident with the thickness center of a plate spring 30 which supports the needle 20. When a feed screw 16 is turned by a step motor 18, a carriage 12 is moved with engagement between a screw part 16n and the needle 20. In this case, the load P produced in the moving direction of the needle 20 is applied to the spring 30 supporting the needle 20. However the load P is applied within the thickness and in the lengthwise direction of the spring 30 and therefore the deformation of the spring 30 means the strains due to compression and can be neglected. As a result, the spring 30 has no flexion cause in the direction orthogonal to a plane. Thus the carriage 12 never produces a position error.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a magnetic head feeding device that performs recording and reproduction on a rotating magnetic sheet.

"Prior art and its problems" Various devices have been put into practical use that magnetically record information on a rotating magnetic sheet (floppy disk) and reproduce it. This 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 on a rotating magnetic sheet, the rotational motion of the step motor is converted into the linear motion of a carriage supporting the magnetic head. Conventionally, as a type of this motion conversion mechanism, the fourth
A device using a feed screw and a needle as shown in FIG. 5 is used.

The magnetic helad 11 is fixed to a carriage 12, and this carriage 12 is guided to move in a direction parallel to the radial direction (X direction) of the rotating magnetic sheet 14 by left and right guide rails 13. Directional movement is restricted. Reference numeral 15 denotes a spindle motor that rotationally drives the rotating magnetic seam 14.

A 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 stepper motor 18 via a force and a pull 17. A threaded portion 16n of the feed screw 16 is located between the front and rear guide walls 12a of the carriage 12.

A needle 20 is supported on the carriage 12 and is located between the threads of the threaded portion 16n. This needle 20 has a needle block 21 that straddles the threaded portion 16n.
This needle block 2 has its both ends fixed to
1 is fixed downwardly to substantially the center shaft of the leaf spring 23 via a fixing screw 22. The leaf spring 23 has its front and rear ends fixed to the guide wall 12a of the carriage 12 via a fixing screw 24, and as a result, the elasticity of the leaf spring 23 biases the needle 20 in the axial direction of the leaf spring 23. Thus, the needle 20 and the threaded portion 16n are fitted together without play in the radial direction of the feed screw 16. Reference numeral 25 denotes a compression spring that pushes the carriage 12 in one direction in the axial direction of the feed screw 16 to take up the axial play between the threaded portion 16n and the needle 20, and at the same time forces the carriage 12 to adjust the engagement point between the threaded portion 16n and the needle 20. A moment is generated around the center to remove play in the radial direction between the carriage 12 and the guide rail 13.

The magnetic head feeding device having the above configuration includes a step motor 18
When driven, the feed screw 16 rotates according to the step angle of the step motor 18. Then, the carriage 12 engaged with the threaded portion 16n by the needle 20 moves to the threaded portion 16n.
The magnetic disk 11 records data at a track pitch corresponding to the step angle of the step motor 18 on the rotating magnetic sheet 14 that moves in the radial direction of the rotating magnetic sheet 14 according to the lead angle of n, and thus is rotated by the spindle motor 15. be able to.

However, in this conventional device, since the needle 20 is fixed to the leaf spring 23 via the needle block 21, a certain distance Me is created between the thickness center of the leaf spring 23 and the axis of the needle 20. Therefore, in the conventional device, when the carriage 12 is moved by the step motor 18, the plate spring 23 is deflected, and this deflection changes the position of the carriage 12, that is, the position of the magnetic heald 11.
There was a problem that the track position was inaccurate.

FIG. 6 is a model diagram explaining this deflection.

Since the leaf spring 23 is fixed to the carriage 12 at both its front and rear ends by fixing screws 24, the hatching in Figure 0, which corresponds to a leaf spring with both ends fixed, indicates this fixed end, and the dashed line indicates the state of the leaf spring 23 before deformation. The solid line indicates the shape of the leaf spring 23 after being deformed by the load P applied to the needle 20. In order to mathematically express the deflection y at an arbitrary position
, where the moment of inertia 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. y is y=-(Mx"/2EI)(x/2d-1/4)
(0≦X≦d/2) Deflection angle 0 is dr/dx・-0Lx/4EI) (3x/d-1) (
0≦X≦d/2) θ at xsd/2 is θ-Md/18EI From this, the movement amount δ1 of the carriage 12 due to deflection is given by δ1=-(Pde 2/16EI) 1-bh 3 /12 .

Here, if P-O, 05kgf, d-15m layer, b
-8 folds, h folds 0.2ts, E=11000kgf
/sm 2. If it is e-4 mm, it becomes δ1·lO 1, which is an amount that cannot be ignored in this type of magnetic head feeding device.

In other words, during recording, the position of the recording track is shifted by two degrees, and during playback, it is difficult to accurately on-track the track recorded at the correct position, and the effective playback track width is reduced. , the S/N ratio of the reproduced signal deteriorates.

``Object of the Invention'' The present invention solves the problems of the conventional magnetic head feeding device, and provides a magnetic head feeding device in which a needle on the carriage side is moved and biased toward the feed screw side by a plate spring. An object of the present invention is to obtain a feeding device that can eliminate movement of a carriage (magnetic head) due to deflection.

"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 axis of the needle and the center of the thickness of the leaf spring. It is characterized by the fact that it was lost.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. FIGS. 1 and 2 show an embodiment of the present invention. The present invention differs from conventional devices in that the axis of the needle 20 and the center of the plate thickness of the leaf spring 30 that supports it are aligned. At the point. Other points are the same as the conventional device, and the same parts are given the same reference numerals. The leaf spring 30 is divided into two parts located on the left and right sides of the feed screw 16, and a thick cylindrical fixing part 31.
31 is formed. 32 is a fixing screw that fixes the leaf spring 30 on the carriage 12.

In this device having the above configuration, when the feed screw 16 is rotated by the step motor 18, the screw portion 16n is rotated as in the conventional device.
The carriage 12 is moved by the engagement between the needle 20 and the needle 20 . At this time, the leaf spring 3 supporting the needle 20
0, a load P in the moving direction of the needle 20 is applied,
Since this load P is applied in the longitudinal direction within the thickness of the leaf spring 30, the deformation that occurs in the leaf spring 30 is a strain due to compression and can be ignored. That is, in the leaf spring 30,
There is no deflection in a direction perpendicular to the plane, so the position of the carriage 12 will not be distorted.

FIG. 3 is a model diagram corresponding to FIG. 6, showing the load P applied to the leaf spring 30. Since the load P is applied within the plane of the leaf spring 30, the carriage 1 generated on the leaf spring 30
The strain δ2 in the moving direction of the leaf spring 30 is expressed as δ2-Pd/4bhE, where E is the longitudinal elastic modulus of the leaf spring 30, b is the width, h is the thickness, and d is the length. Numerical values used in the specific example of deflection calculation, namely P-0.05kgf, dJ5
■■, b-e layer temperature, h seal 0.2 intestinal phoenix, E-
Substituting 113000kg4/■■2, δ2=
Op, m. That is, according to the invention, the leaf spring 30
The carriage 12 does not move due to compressive strain.

The axis of the needle 20 and the thickness center of the leaf spring 23 are
As mentioned above, it is theoretically preferable that they match closely, but
In actual configuration, it is acceptable for the centers of the two to be shifted to the extent that the strain (and deflection) generated in the leaf spring 30 does not cause an error in the track position of the carriage 12. This is what is meant by ``substantially'' making the axial center position and the thickness center of the leaf spring 23 coincide.

Furthermore, in electronic cameras, it is common to have a recording-only magnetic head feeding device on the camera side and a separate playback device, but the "magnetic recording and playback device" referred to in the present invention is a device that performs only one side of recording and playback. including.

"Effects of the Invention" As described above, the present invention provides a magnetic head feeding device that presses a needle on a carriage side having a magnetic head against a feed screw rotationally driven by a motor via a plate spring. Since the center of the thickness of the leaf spring is substantially aligned with the center of the thickness of the leaf spring, when the carriage is fed by the feed screw, the leaf spring does not bend and disturb the position of the magnetic head. Since recording can be performed and the recording track can be correctly placed on the recording track during reproduction, a reproduction signal with a high S/N ratio can be obtained without deteriorating the reproduction signal.

[Brief explanation of drawings]

1 is a perspective view of the main parts showing an embodiment of the magnetic head feeding device according to the present invention, FIG. 2 is a side view of the same, FIG. 3 is a model diagram showing the force relationship in the configuration of FIG. 2, and FIG. 5 and 6 are a perspective view, a side view, and a model view of a conventional magnetic head feeding device, respectively, corresponding to FIGS. 1, 2, and 3. 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. Patent applicant: Asahi Optical Industry Co., Ltd. Agents: Kunio Miura, Matsui and Figure 1 Figure 2 Figure 6 Figure 4 Figure 5

Claims (1)

[Claims] (1) A carriage that supports a magnetic head, a guide means that guides the carriage so that the magnetic head moves in the radial direction of the rotating magnetic sheet, and is oriented in the moving direction of the carriage and is rotationally driven by a step motor. A magnetic head feeding device for a magnetic recording and reproducing device comprising a feed screw, a needle located between the 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 device, characterized in that the axis of the leaf spring substantially coincides with the center of the thickness of the leaf spring.