JPH02166662A - magnetic disk device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic disk device suitably used for writing and reading information to and from a magnetic disk, and particularly relates to a magnetic disk device in which a magnetic disk or the like is mounted on a spindle motor. The present invention relates to a magnetic disk device in which the balance during rotation can be adjusted even after the rotation.

[Prior Art] Generally, a housing, a spindle motor provided in the housing and having a rotating shaft, a hub member provided on the rotating shaft of the spindle motor and rotating integrally with the rotating shaft, and the hub 2. Description of the Related Art A magnetic disk device comprising a magnetic disk fixed to a member via a disk clamp is known.

In this type of magnetic disk device, a spindle motor rotates the magnetic disk at high speed, and a magnetic head is placed on the disk surface of the magnetic disk, for example, at 0.000.
The magnetic disk is made to float with a minute gap of about 2 to 0.4 μm, and information is written and read onto and from the magnetic disk using this magnetic head.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, when the rotational balance of a high-speed rotating magnetic disk is lost, the minute gap between the magnetic disk and the magnetic head changes, causing problems in information writing and reading operations. In order to avoid harmful effects and vibration of information equipment such as personal computers and word processors equipped with magnetic disk drives, do not install the spindle motor (including the hub member in the case of an in-hub type), disk clamp, magnetic disk, etc. separately. It is designed to have a highly accurate rotational balance.

However, in the conventional technology, when a spindle motor is attached to a housing and a magnetic disk is mounted on the spindle motor via a disk clamp or the like, slight machining errors of each component formed with high precision are accumulated, and the magnetic disk is The rotation may become unbalanced, and there is a problem in that the rotation of the magnetic disk causes rotational shaking, rotational unevenness, and the like.

The present invention has been made in view of the problems of the prior art described above, and the present invention allows the balance during rotation to be easily adjusted even after mounting a magnetic disk, etc., and effectively prevents rotational shaking, rotational unevenness, etc. An object of the present invention is to provide a magnetic disk device that can prevent such problems.

[Means to solve the problem]

A feature of the configuration adopted by the present invention in order to solve the above-mentioned problems is that a shaft hole is formed in the rotating shaft of the spindle motor, and a balance weight that balances the rotation of the magnetic disk is provided in the shaft hole so that its position can be adjusted. That's true.

[Effect]

With the above configuration, by appropriately adjusting the position of the balance weight within the shaft hole formed in the rotating shaft of the spindle motor and fixing the balance weight within the shaft hole, it is possible to easily correct the unbalance that occurs when the magnetic disk rotates. Can be done.

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 4.

1 to 3 show a first embodiment of the present invention.

In the figure, reference numeral 1 indicates a housing having a sealed structure, and a motor mounting hole IA is provided in the base portion IA of the housing 1.
B is formed. Reference numeral 2 indicates an in-hub type spindle motor located in the housing 1 and provided on the base part IA.The spindle motor 2 is mounted on the base part IA so as to close the motor mounting hole IB, and The support member 3 has a cylindrical boss portion 3A extending upwardly.
, a stator coil 4 wound around the outer periphery of the boss portion 3A of the support member 3, a magnet 5 fixed to the inner peripheral surface of a hub member 10, which will be described later, facing the stator coil 4, and a magnet 5 of the support member 3. A rotating shaft 7 is rotatably disposed within the boss portion 3A via bearings 6, 6 and rotates integrally with the hub member 10.
It is roughly composed of.

Here, a shaft hole 7A is bored in the axial direction on the inner diameter of the rotating shaft 7, and a balance weight 1, which will be described later, is provided in the shaft hole 7A.
4 is provided so that its position can be adjusted. Further, a spring 8 is disposed between each of the bearings 6 and is positioned between the rotating shaft 7 and the boss portion 3A, and the spring 8 is configured to receive a thrust load acting between the bearings 6 and 6. It has become. Reference numeral 9 indicates a magnetic seal located between the rotating shaft 7 and the boss portion 3A and provided on the upper end side of the boss portion 3A. 7 to prevent external dust and the like from entering into the housing 1.

Reference numeral 10 denotes a hub member that constitutes a part of the spindle motor 2 and rotates integrally with the rotating shaft 7. The hub member 10 is formed into a closed cylinder shape, and the protruding end of the rotating shaft 7 is attached to the lid portion 10A. A fitting hole 10B is formed into which the fitting hole 10B is fitted. Also,
An annular flange 10G projecting radially outward is formed on the lower end side of the hub member 10, and a magnetic disk 11, which will be described later, is held on the flange 10C. A magnet 5 is fixed to the inner circumferential surface of the hub member 10 facing the stator coil 4, and the hub member 10 rotates together with the rotating shaft 7 via the magnet 5 by supplying power to the stator coil 4. It is designed to be driven.

11.11. . . . indicates, for example, three magnetic disks disposed on the outer peripheral side of the hub member 10 via spacers 12, 12, and 13 indicates a disk clamp screwed onto the lid portion 10A of the hub member 10. The disk clamp 13 clamps each magnetic disk 11 on the flange 10C of the hub member 10 via each spacer 12, and rotates each magnetic disk 11 integrally with the hub member 10 at high speed. A magnetic head (not shown) is arranged on the upper and lower disk surfaces 11A and IIB of each magnetic disk 11 with a gap of about 0.2 to 0.4 gm, so that information can be written and read. It has become.

Reference numeral 14 indicates a balance weight provided in the shaft hole 7A of the rotating shaft 7, and the balance weight 14 has an inner diameter of the shaft hole 7A, as shown in FIGS. 2 and 3.

An elastic cylindrical body 15 formed into a substantially cylindrical shape with an outer diameter D2 slightly larger than that of the elastic cylindrical body 15 whose diameter can be expanded and contracted by a slit 15A extending in the axial direction;
The weight member 1 consists of a weight member I6 formed into an arch shape by cutting a part of a cylinder in the axial direction.
6 is adapted to make the center of gravity of the entire balance weight 14 eccentric from the center of the cylindrical body 15 and the shaft hole 7A.

Furthermore, an engagement groove 16A that engages with a tool such as a screwdriver is formed on the upper surface of the weight member 16, and the balance weight 14 is attached to the rotating shaft 7 while the elastic cylindrical body 15 is reduced in diameter through the slit 15A. The weight member 16 is fitted into the shaft hole 7A and rotated in the direction of arrow A in FIGS. be slid. The balance weight 14 is positioned at an optimal adjustment position within the shaft hole 7A by the force of expanding the diameter of the elastic cylindrical body 15, thereby adjusting the rotational balance of the magnetic disk 11 and the like. The balance weight 14 may be adjusted to an optimal position within the shaft hole 7A and then fixed within the shaft hole 7A using silver solder or the like.

Further, reference numeral 17 indicates a grounding means for dissipating static electricity generated by friction with air on each magnetic disk 11 etc. rotating at high speed to the housing 1. The electrode ball 18 is positioned and fixed, the contact 19 is in contact with the ball 18, one end is screwed to the base part IA of the housing 1, and the other end is connected to the bottom surface of the ball 18. A spring plate 20 is pressed at all times to release static electricity generated in the magnetic disk 11 and the like to the housing 1 via the hub member 10, the rotating shaft 7, and the like.

The magnetic disk device according to this embodiment has the above-described configuration, and when power is supplied to the stator coil 4 of the spindle motor 2 from the outside, the hub member 10 with the magnet 5 provided at a position facing the stator coil 4 is rotationally driven together with the rotating shaft 7, causing each magnetic disk 11 to rotate at high speed around the rotating shaft 7. The disk surfaces 11A and IIB of each magnetic disk 11 have 0.2 to 0.
The magnetic head is positioned with a gap of about 4 μm,
Information is written to and read from the respective disk surfaces 11A and IIB.

By the way, spindle motor 2. Each magnetic disk 11.
Each spacer 12, disk clamp 13, etc. is individually formed with high precision rotational balance to prevent unbalance such as rotational shaking or rotational unevenness from occurring when each magnetic disk 11 rotates. , as shown in FIG. 1 for the spindle motor 2 (when each magnetic disk 11, etc. is mounted, errors in each component are accumulated, and as described in the prior art, the rotational balance of each magnetic disk 11, etc. is lost). It ends up.

Therefore, in this embodiment, the rotating shaft 7 of the spindle motor 2
A shaft hole 7A is bored in the shaft hole 7A, a balance weight 14 is inserted into the shaft hole 7A, and the position is adjusted by sliding the balance weight 14 appropriately in the shaft hole 7A in the axial direction and circumferential direction. The rotational balance can be easily adjusted after mounting the magnetic disk 11 and the like. That is, the balance weight 14 is an elastic cylindrical body 15 having a slit 15A.
The center of gravity of the balance weight 14 is eccentric with respect to the center of the elastic cylindrical body 15 and the shaft hole 7A. The rotational balance of each magnetic disk 11 etc. can be easily adjusted by adjusting the position by sliding it in the direction of arrow A in FIGS. It is possible to effectively prevent the occurrence of rotational shaking, rotational unevenness, etc.

In addition, in this embodiment, since the shaft hole 7A is bored in the rotating shaft 7 and the rotating shaft 7 has a hollow structure, the weight of the entire spindle motor 2 including the rotating shaft 7 can be reduced, and the weight of the magnetic disk device can be reduced. It is possible to aim for Furthermore, since the rotational balance can be adjusted after mounting each magnetic disk 11, etc.,
Spindle motor 2. There is no need to form the spacer 12, disk clamp 13, etc. with such high precision, and it becomes possible to manufacture these at relatively low cost. By optimally adjusting the rotational balance of each magnetic disk 11, the friction noise between each magnetic disk 11 and the air can be effectively reduced, and a quiet magnetic disk device without abnormal noise can be provided. be effective.

Next, FIG. 4 shows a second embodiment of the present invention. In this embodiment, the same components as those in the first embodiment are given the same reference numerals, and their explanations will be omitted. The feature of this embodiment is that spline grooves 21 are lined up on the circumferential surface of a shaft hole 7A drilled in the rotating shaft 7, and spline grooves 21 are arranged on the outer circumferential surface of a balance weight 22 that is inserted into the shaft hole 7A. This is because another spline groove 23A having a complementary shape is arranged in a row. Here, the balance weight 22 has spline grooves 2 on its outer circumferential surface.
A cylindrical body 23 in which 3A is formed, and the cylindrical body 23
A bow-shaped weight member 24 is fixed therein. Note that the weight member 24 may be integrally formed within the cylindrical body 23.

Thus, in this embodiment configured as described above, the balance weight 22 is rotated in the direction of the arrow A, and the balance weight 22 is inserted into the shaft hole 7A in the direction of the arrow B at the optimal rotational position. By positioning the balance weight 22 at an optimal position in the axial direction within the shaft hole 7A while engaging the spline grooves 21 and 23A with each other, the rotational balance of each magnetic disk 11 can be optimally adjusted, which is similar to the first embodiment. Almost the same effects as in the example can be obtained.

In addition, in each of the above embodiments, the balance weight 14 (22
) has been described as having a bow-shaped weight member 16 (24);
3) It is sufficient that the weight member is eccentric to the center of the shaft hole 7A and has a vine shape, for example, a weight member formed in the shape of a column with a small diameter is fixed to the inner circumferential surface of the cylindrical body 15 (23) at one location. You can.

Further, in each of the embodiments described above, the shaft hole 7A is bored through the rotary shaft 7 in the axial direction, but instead of this, the shaft hole 7A may be formed as a bottomed hole.

Further, in each of the above embodiments, the in-hub type spindle motor 2 has been described as an example, but an outer rotor type spindle motor may be used instead.

〔Effect of the invention〕

As detailed above, according to the present invention, a shaft hole is formed in the rotating shaft of the spindle motor, and a balance weight for balancing the rotation of the magnetic disk is provided in the shaft hole so that the position of the balance weight can be adjusted. By adjusting and positioning the balance weight to the optimum position within the hole, the rotational balance can be easily adjusted after mounting the magnetic disk, etc., and a quiet magnetic disk device without abnormal noise can be provided. Moreover, by making the rotating shaft hollow, various effects can be achieved, such as reducing the weight of the spindle motor.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is a vertical sectional view of main parts of a magnetic disk drive, FIG. 2 is a perspective view of a balance weight, and FIG. 3 is a perspective view of a balance weight. The plan view and FIG. 4 are exploded perspective views of a rotating shaft and a balance weight showing a second embodiment. 1...Housing, 2...Spindle motor, 7.
...Rotating shaft, 7A...Shaft hole, 10...Hub member, 1
1...Magnetic disk, 12...Spacer, 13...
・Disc clamp, 14. 2... Balance weight, 16°24... Weight member. Patent applicant Tokiko Co., Ltd.

Claims (1)

[Claims] A housing, a spindle motor provided in the housing and having a rotating shaft, a hub member provided on the rotating shaft of the spindle motor and rotating integrally with the rotating shaft, and a hub member connected to the hub member via a disk clamp. In a magnetic disk drive comprising a fixed magnetic disk, a shaft hole is formed in the rotating shaft of the spindle motor, and a balance weight for balancing the rotation of the magnetic disk is provided in the shaft hole so that the position thereof can be adjusted. A magnetic disk device featuring: