JPH0237171Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a head positioning device, and is particularly suitable for use in positioning a head in a floppy disk device.

[Background technology and its problems]

Head positioning devices used to position the head at a predetermined position on the disk in a floppy disk device include a belt drive type and a lead screw type.

A belt-driven head positioning device connects a head carriage to a belt fed by a stepping motor, thereby positioning the head according to the rotational angular position of the stepping motor via the belt. The access speed is fast, but the positioning accuracy is poor. On the other hand, in the lead screw method, the head carriage is screwed into engagement with the lead screw rotated by the stepping motor, and the head carriage is moved into the thread groove of the lead screw in accordance with the rotational position of the stepping motor. This method has slow access speed but high accuracy.

Therefore, it is considered that if the access speed can be increased in the lead screw type head positioning device, a head positioning device with high positioning accuracy and high access speed can be obtained.

Considering the configuration of a lead screw type head positioning device from this point of view, in order to increase the access speed compared to conventional devices, the first thing to do is to reduce the inertia of the stepping motor or the rotational drive system of the lead screw. It is thought that it is effective to reduce the diameter of the stepping motor rotor. However, since this reduces the output torque of the stepping motor, it is necessary to reduce the load on the lead screw or head carriage, which is a load on the stepping motor, as much as possible.

One possible way to solve this problem is to reduce the diameter of the lead screw and narrow the width of the guide of the head carriage that engages with the lead screw. It is necessary to reduce the load on the step motor and to minimize the generation of a load on the step motor when assembling the step motor and lead screw in a predetermined position relative to the floppy. Incidentally, if the diameter of the lead screw is made smaller, it becomes easier to deflect in the thrust direction.

[Purpose of invention]

This idea was created taking the above points into consideration.
The present invention attempts to propose a structure for the step motor and lead screw so that the load on the step motor and the force acting in the thrust direction can be minimized as much as possible.

[Summary of the idea]

In order to achieve this purpose, in this invention,
First and second bearings for holding the lead screw and the rotational output shaft are provided at both ends of the lead screw that is integrated with the rotational output shaft of the motor, and
This bearing is positioned and fixed to the fixing part by a bearing fixing part which is held in contact with the first and second surfaces by a leaf spring.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings. In Figs. 1 to 3, reference numeral 1 denotes a motor serving as a drive source for head positioning, that is, a step motor. A rotor 3 is fixed to one end of the rotary output shaft 2, and the rotor 3 is rotated by a stator 4 facing the rotor 3. It is designed to generate torque. The other end of the rotary output shaft 2 projects outward from the step motor 1, and a lead screw 6 is integrally formed on the projecting end to which a head carriage 5 is screwed and engaged.

Although the detailed configuration is not shown in the drawings, a head is attached to the head carriage 5 so that the lead screw 6 faces a floppy disk arranged almost parallel to it. By sliding the head in the direction in which the user 6 extends, the head can be positioned at a predetermined position facing the floppy disk.

The stator 4 has a base 1 disposed at its inner end.
1, and a first bearing 12 that pivotally supports the rotary output shaft 2 is fixed at approximately the center of the base 11. The base 11 is configured to position the lead screw 6 in the axial direction by coming into contact with a bearing fixing portion 14 mounted on a substrate 13 of the floppy disk device from the side. This bearing fixing portion 14 fixes the bearing 12 mounted on the base 11 onto the substrate 13.

On the other hand, the bearing fixed portion 1 on the substrate 13
A second bearing fixing part 15 is attached to a position facing the lead screw 6, and a second bearing 16 attached to the tip of the lead screw 6 is attached to the second bearing fixing part 15 by this bearing fixing part 15.
is fixed on the substrate 13.

The bearing fixing parts 14 and 15 have, for example, a positioning member 21 having an L-shaped longitudinal section, as is particularly clear in FIG. Therefore, the height and lateral positions of the bearings 12 and 16, and thus the lead screw 6, facing the substrate 13 are respectively regulated. In this embodiment, the outer circumferential surfaces of the bearings 12 and 16 have a circular cross section, so that the outer circumferential surfaces of the bearings 12 and 16 have a circular cross section.
2 and the vertical surface portion 23, the lead screw 6 passing through the center can be positioned.

A plate spring 24 having an F-shaped cross section is screwed to the upper ends of the bearing fixing parts 14 and 15 by screws 25, and its right end extends to a position opposite to the horizontal surface part 22 and the vertical surface part 23. By resiliently coming into contact with the outer peripheral surfaces of the bearings 12 and 16, the bearings 16 and 12 are pressed and fixed to the horizontal surface portion 22 and the vertical surface portion 23 of the bearing fixing portions 15 and 14.

In this embodiment, a retaining ring 31 fitted into a groove provided in the lead screw 6 is provided inside the bearing 16 on the tip side of the lead screw 6, and the bearing 16 comes into sliding contact with this ring 31. A retaining pin 32 erected from the substrate 13 contacts the bearing 16 from the outside, thereby positioning and holding the bearing 16 at the position of the bearing fixing portion 15 in the direction of extension of the lead screw 6.

In the above configuration, the rotary output shaft 12 is attached to the step motor 1 prior to assembly of the floppy disk device. That is, the bearing 12 is formed by inserting the rotating output shaft into the base 11.
is fixed to a base 11, and a stator 4 is attached so as to surround the rotor 3, so that the rotary output shaft 2 is extended outwardly.
is assembled. A bearing 35 fixed to the stator 4 is provided at a position opposite to the bearing 12 of the rotor 3, so that the rotor 3 within the stator 4 can be rotated smoothly.

Separately from this, a pair of opposing bearing fixing parts 14 and 15 are mounted on the substrate 13. In the assembly process of Naeko, the leaf spring 24 and screw 25 are not attached.

When assembling the floppy disk device, the head carriage 5 is first screwed onto the protruding end of the rotary output shaft 2, and then the retaining ring 31 is fitted to the tip of the lead screw 6, and then the bearing 16 is inserted.

In this way, a state is obtained in which the two bearings 12 and 16 are mounted on the rotational output shaft 2, and these bearings 12 and 16 are attached to the horizontal plate portions 22 of the bearing fixing portions 14 and 15.
and placed on the vertical plate section 23.

In this state, by attaching the retaining pin 32 to the outside of the bearing 16, the bearing 16 is fixed to the bearing fixing portion 1.
5 position, and then attach the leaf spring 24 onto the bearing fixing parts 14 and 15 with the screw 25.
At this time, the leaf spring 24 uses its elastic force to cause the bearing 12 to
and 16 onto the horizontal surface portions 22 and 23, thereby acting to press and fix the bearings 12 and 16.
is positioned and held on the substrate 13 at a position determined by the surface portions 22 and 23.

According to the above configuration, the rotary output shaft 2 of the step motor 1 is integrated with the lead screw 6, so when the lead screw 6 is considered as a load on the output side of the step motor 1, the lead screw The value of the load for rotating the U 6 can be small. Incidentally, if the rotary output shaft of the step motor 1 is coupled to the lead screw via a separate coupling means, the coupling means may become an extra load, but with the above configuration, the rotary output shaft 2 and Since the lead screw 6 and the lead screw 6 are integrally configured, such a fear can be effectively avoided.

Further, according to the above-described configuration, there are two support points for the rotary output shaft 2 and the lead screw 6 with respect to the substrate 13.
(i.e., the bearings 12 and 16), it is possible to prevent unnecessary force from acting on the lead screw 6 in the thrust direction. Incidentally, it may be possible to have a structure in which the bearing 35 provided at the other end of the rotary output shaft 2 is fixed to the substrate 13, but these 3
Since it is extremely difficult in practice to ideally arrange the points on a line, an extra force in the thrust direction is applied to the lead screw 6, which reduces the load on the step motor 1. However, the above-described configuration can prevent such a risk. This means that even if the diameter of the lead screw 6 is made smaller, the negative effect can be reduced.Thus, by reducing the inertial force of the lead screw 6, the access speed of the head carriage 5 by the step motor 1 can be increased. It means.

In order to obtain such a two-point bearing structure, the leaf springs 24 of the bearing fixing parts 14 and 15 press the bearings 12 and 16 onto the surface parts 22 and 23 when assembling the floppy disk device. The two-point support position of the lead screw 6 and thus the rotary output shaft 2 can be accurately and easily positioned simply by tightening the lead screw 6 with the screw 25.

[Effect of idea]

As described above, according to the present invention, by integrally forming the rotary output shaft of the rotary drive source and the lead screw, the load on the drive source can be reduced, and the rotary output shaft and the lead screw are integrally formed. By supporting the board to be fixed at two points, it is possible to effectively avoid applying extra load to the rotational drive source during assembly, and thus to reduce the inertial force applied to the rotational output shaft as a whole. By making the head smaller, a head positioning device with a faster head access speed can be obtained. In this way, the advantages of the step motor system, which provides high head positioning accuracy, can be obtained without sacrificing the advantages.

[Brief explanation of the drawing]

1, 2, and 3 are a longitudinal sectional view, a side view, and a transverse sectional view showing an embodiment of the head positioning device according to the present invention. 1...Step motor, 2...Rotation output shaft, 3
... Rotor, 4 ... Stator, 5 ... Head carriage, 6 ... Lead screw, 11 ... Base, 12, 16 ... Bearing, 13 ... Board, 14,
15...Bearing fixing part, 21...Positioning member, 2
2, 23...horizontal and vertical surface parts, 24...plate springs,
25...Screw.

Claims (1)

[Scope of utility model registration request] A head carriage engaged with a lead screw integrally formed with the rotary output shaft of the motor is configured to slide in accordance with the rotation of the rotary output shaft, and the rotary output shaft and the lead screw integrally formed at both ends of the lead screw are arranged to slide. First and second bearings are provided for holding the U, and the first and second surface portions extend in mutually different directions, and the first and second bearings are held in contact with the first and second surface portions, respectively. A head positioning device, characterized in that the first and second bearings are positioned and fixed to the fixing part by a bearing fixing part having a leaf spring.