JPH0741757U - Magnetic disk unit - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a mechanism for attaching a magnetic disk to a spindle motor that does not cause distortion in the magnetic disk. [Structure] On the hub upper surface of the spindle motor, a ring-shaped precision machining surface and a jig attachment surface for attaching a jig for machining the precision machining surface are provided in the central portion, and a spacer to which a magnetic disk is bonded is The ring-shaped precision machined surface is assembled, and the upper part of the portion in contact with the precision machined surface is fixed with a clamper.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnetic disk device, and more particularly to a mechanism for attaching a magnetic disk to a spindle motor.

[0002]

[Prior art]

 In the magnetic disk device, in recent years, the track density and the line density have been increased for higher capacity, and the output obtained from the magnetic head has been miniaturized. For this reason, attempts have been made to increase the output by reducing the flying height of the magnetic head flying over the magnetic disk. As a result, the magnetic head collides with the convex portion of the magnetic disk and is liable to be destroyed, leading to a risk of head crash.Therefore, it is required to reduce the deflection and distortion of the magnetic disk mounted on the spindle motor. .

In a magnetic disk device, particularly in a small-sized magnetic disk device in which the outer diameter of the magnetic disk is 1.8 inches or less and the number of mounted disks is about two, a mechanical mechanism currently used and a spacer are used. A mechanism for attaching the magnetic disk to the spindle motor by adhering to the spindle motor will be described.

First, the structure of a spindle motor generally used in a small magnetic disk device will be described. As shown in FIGS. 5 and 6, the coil 5 and the core 6 forming the magnetic circuit are fixed to the bracket 7 which is the base member of the spindle motor 4, and the magnet 8 is fixed to the hub 10 via the yoke 9. . The rotating shaft 10e provided at the center of the hub 10 is held by bearings 11a and 11b which are preloaded to suppress axial play and radial play, so that the hub 10 can rotate stably with less runout. There is.

Although the constituent parts of the spindle motor 4 are manufactured by precision machining, the finished hub 10 is distorted and shakes during rotation due to variations in parts accuracy and assembly errors. In order to remove this, as shown in FIG. 7, after the spindle motor is completed, a processing machine such as a lathe is used, the bracket 7 is fixed by the chuck 20, and the upper surface of the hub 10 is pressed by the rubber member 22 having a large friction coefficient. Then, it is rotated, and the receiving surface 10c 'of the stepped portion 10c of the hub 10 is cut by the cutting tool 23 to form a precision machined surface, thereby correcting the distortion and the shake. The magnetic disk 1 is generally attached to the step portion 10c of the hub.

As shown in FIG. 5, a magnetic disk mounting mechanism using a mechanical mechanism inserts a disk spacer 25 between the magnetic disk 1 for determining the height between two magnetic disks 1, and a hub step of the spindle motor 4 is inserted. It is incorporated in the section 10c. The magnetic disc 1 is pressed and fixed to the hub step portion 10c by the tightening force of the clamper set screw 13 being applied via the clamper 12.

However, in the mechanical mechanism described above, the surface precision of the clamper pressing surface 12 'of the clamper 12 for pressing the magnetic disk 1 and the receiving surface 10c' of the hub step portion 10c for receiving the magnetic disk 1 is controlled with high accuracy. Otherwise, the clamping force by the clamper set screw 13 will not be applied evenly to the magnetic disk 1 via the clamper 12, and the magnetic disk 1 will be distorted. Especially thin 1. This phenomenon is remarkable in a magnetic disk of 8 inches or less. For this reason, in recent years, a method has been adopted in which a magnetic disk is adhered to a spacer and the spacer is screwed and fixed to a spindle motor.

In FIG. 6, a magnetic disk 1 is attached to a spacer 2 with an adhesive 3, the spacer 2 is incorporated in a hub step portion 10 c of a spindle motor 4, and a clamper 12 and a clamper set screw 13 are used. It is fixed. Therefore, the magnetic disk 1 has a mechanism in which no mechanical stress is directly applied to the magnetic disk 1 due to the screw tightening force and no distortion occurs.

[0009]

However, the hub 10 is made of an aluminum alloy having a relatively low strength in order to improve workability. Further, the magnetic disk 1 has recently been reduced in diameter to 1.8 inches, and further to 1.3 inches with the downsizing of magnetic disk devices. However, since the capacity is required to be high, it is necessary to secure the data recording surface of the disk as large as possible. For this reason, the hole diameter of the center hole 1a of the magnetic disk 1 used for incorporation in the spindle motor 4 is smaller than the outer diameter of the magnetic disk of 3.5 inches and 2.5 inches. There is.

On the other hand, the small-sized magnetic disk device is incorporated in a small-sized information device, and is dropped by the carelessness of the user during transportation, and the chance of receiving a large shock is increasing. Therefore, it is desirable that the bearings 11a and 11b of the spindle motor 4 have as large a diameter as possible in order to improve impact resistance. Further, as described above, it is necessary to suppress the runout of the spindle motor 4 during rotation as much as possible, and the span of the two bearings 11a and 11b needs to be long while the thinning of the magnetic disk device is required. The upper bearing 11a must be housed inside the center hole 1a of the magnetic disk 1.

As a result, the thickness of the hub side surface portion 10d of the spindle motor 4 cannot be sufficiently secured, and the thickness is reduced. Therefore, in the mechanism shown in FIG. 6, the tightening force by the clamper set screw 13 is applied to the hub step portion 10c via the clamper 12 and the spacer 2, and the hub 10 is deformed in the arrow direction of FIG. The spacer 2 is also deformed like the hub 10, so that the magnetic disk 1 is distorted.

Therefore, the present invention is intended to provide a mechanism for attaching a magnetic disk to a spindle motor, which is free from attachment distortion.

[0013]

[Means for Solving the Problems]

 In order to achieve the above object, in the magnetic disk mounting mechanism of the present invention, a spacer to which a magnetic disk is adhered is incorporated into a ring-shaped precision machined surface formed on the upper surface of the hub of the spindle motor to prevent deformation of the hub. It is characterized in that the upper part of the surface of the spacer in contact with the precision machined surface is fixed by a clamper so as not to occur.

[0014]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a main part of a magnetic disk device according to an embodiment of the present invention, FIG. 2 is a plan view of a spindle motor according to the embodiment of the present invention, and FIGS. 3 and 4 show a hub processing method. FIG. The spindle motor has the same structure as the conventional example. As shown in FIGS. 1 and 2, the magnetic disk 1 is attached to the spacer 2 with an adhesive 3. The spacer 2 is incorporated into a ring-shaped precision machined surface 10b formed on the upper surface of the hub of the spindle motor 4, and the spacer 2 is clamped by a clamper 12 and a clamper set screw 13 at the upper part of the surface in contact with the precision machined surface 10b. It is fixed at 10.

As shown in FIGS. 3 and 4, a rubber member 21 having a diameter smaller than a normal diameter or a rubber member 22 having a normal diameter is formed at the center of the upper surface of the hub in the correction processing after the completion of the spindle motor described above. A jig mounting surface 10a for mounting the processing jig 24 for pressing is provided. The processing jig 24 is fixed to the hub 10 by using the clamper set screw hole 10f provided in the hub 10. As a result, the periphery of the jig mounting surface 10a can be processed by a processing machine such as a lathe, and the upper surface of the hub has a ring shape with less distortion and runout during rotation, which cannot be secured by the conventional processing method. The precision machined surface 10b can be secured.

[0016]

[Effect of device]

 The magnetic disk mounting mechanism of the present invention incorporates a spacer, to which a magnetic disk is adhered, onto the hub upper surface with sufficient strength and less distortion when the spindle motor rotates. Therefore, the mounting distortion of the magnetic disk does not occur, the risk of head crash is reduced, the magnetic head can operate stably with a low flying height, and the capacity of the magnetic disk device is increased. It greatly contributes to.

[Brief description of drawings]

FIG. 1 is a sectional view showing a magnetic disk mounting mechanism of a spindle motor according to an embodiment of the present invention.

FIG. 2 is a plan view showing a spindle motor according to an embodiment of the present invention.

FIG. 3 is a diagram showing a first processing method of a spindle motor according to an embodiment of the present invention.

FIG. 4 is a diagram showing a second machining method of the spindle motor according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a conventional magnetic disk mounting mechanism by a mechanical mechanism.

FIG. 6 is a cross-sectional view showing a conventional magnetic disk attachment mechanism by a method of adhering to a spacer.

FIG. 7 is a diagram showing a method for processing a hub step portion of a conventional spindle motor.

[Explanation of symbols]

 1 magnetic disk 1a magnetic disk center hole 2 spacer 3 adhesive 4 spindle motor 5 coil 6 core 7 bracket 8 magnet 9 yoke 10 hub 10a jig attachment surface 10b precision machined surface 10c hub step 10c 'receiving surface 10d hub side surface 10e rotating shaft 10f clamper set screw hole 11a, 11b bearing 12 clamper 12 'clamper pressing surface 13 clamper set screw 14 base 20 chucks 21, 22 rubber member 23 bytes 24 processing jig 25 disk spacer

Claims (1)

[Scope of utility model registration request] 1. A magnetic disk for recording and reproducing information, a spindle motor for rotating the magnetic disk at a predetermined speed, a spacer for bonding the magnetic disk, and a clamper for fixing the spacer to the spindle motor. In the magnetic disk drive having the spacer, the spacer is incorporated in a ring-shaped precision machining surface formed on a hub upper surface of the spindle motor, and an upper portion of a portion in contact with the precision machining surface is fixed by the clamper. Characteristic magnetic disk device.