JPH0438139A - Motor - Google Patents

Abstract

PURPOSE:To seal the interior of a motor and to considerably make thin the motor by forming a labyrinth space, composed of micro gaps, between the stator section and the rotor section. CONSTITUTION:A recess 25B is formed such that the gap 40 formed by the outer circumferential face 26C of an annular protrusion 26B and the step face 25C of the recess 25B will be smaller than 0.2mm under a state where a rotary hab 28 is engaged with a fixed shaft 23 through bearings 31, 32, while furthermore the lower end face of the annular protrusion 26B does not contact with the upper side face 25D of the recess 25B. On the other hand, a gap 42 between the outer circumferential face 27B of a yoke section 27 and the inner circumferential face 22B of a fixed member 22 is set smaller than 0.2mm and the gap is kept when the rotary hab 28 rotates around the fixed shaft 23.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a motor, and is suitable for application to, for example, a motor configured to rotate a magnetic disk.

B Summary of the Invention The present invention provides a motor with a sealed structure by forming a labyrinth space consisting of a minute gap between a fixed part and a rotating part, thereby making the motor thinner. It can be shaped.

C. Prior Art Conventionally, as shown in FIG. 3, a motor designed to rotate a magnetic disk, for example, has a cylindrical retaining portion 3A provided at the center of the plane of a flange-shaped fixing member 3. A bearing 4 is provided on the inner circumferential surface of the retaining portion 3A.
and 5, the outer ring portions 4A and 5A are fitted.

Further, the inner ring portions 4B and 5B of the bearings 4 and 5 fit and fix the rotary shaft 6 on the inner circumferential surfaces thereof, so that the retaining portion 3A rotatably holds the rotary shaft via the bearings 4 and 5.

An engagement hole 8B of a cylindrical rotating hub 8 is fixed to the rotating shaft 6 by press fit or adhesive, so that the rotating hub 8 rotates together with the rotating shaft 6.

Further, an iron core 10 made of laminated metal plates is fitted and fixed on the outer circumferential surface of the engaging portion 3A, and a conductive wire 9 is wound around the iron core 10 to form a coil portion, and the inner part of the rotating hub 8 is wound with a conductive wire 9. An annular magnet 12 fixed to the circumferential surface is configured to face the iron core 10, thereby forming a magnetic circuit, and by conducting a driving current to the coil portion, the rotating hub 8 is rotationally driven. ing.

Therefore, a magnetic disk (not shown) fitted and fixed to the outer circumferential surface 8A of the rotary hub 8 is rotated integrally with the rotary hub 8.

Here, a magnetic fluid sealing member 15 is provided between the inner circumferential surface of the retaining portion 3A and the rotating shaft 6, so that minute dust caused by bearing grease etc. generated from the bearing 4 is not scattered to the outside. It is done like this.

Therefore, it is possible to prevent dust from adhering to the surface of the magnetic disk fitted and fixed to the outer circumferential surface 8A of the rotating hub 8, and thereby the information recorded on the magnetic disk can be reliably read.

Problems to be Solved by the Invention In this type of magnetic disk device, it is thought that user-friendliness can be improved by making the magnetic disk device much smaller and thinner.

However, since the magnetic fluid sealing member 15 is provided in the motor 1 constituting the magnetic disk device, the motor 1 can be made thinner, which makes it impossible to downsize the magnetic disk device as a whole.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a motor that can seal the inside of the motor and can be made even thinner.

E! II! Means for Solving the Problems In order to solve this problem, in the present invention, the fixing part 2
5 and the rotating part 2 rotatably engaged with the fixed part 25.
8, a labyrinth space 40 consisting of a small gap is formed between the fixed part 25 and the rotating part 28, and the inside 31, 32 of the motor 20 is sealed.

When the rotating part 28 of the F-action motor 20 rotates, a low-pressure labyrinth space 40 is formed, thereby making it possible to seal the inside of the motor (31 and 32).

Therefore, the motor 20 can be made thinner without using a conventional magnetic fluid sealing member.

G example An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 20 generally indicates a motor for driving the rotation of a magnetic disk of a magnetic disk device, and a retaining protrusion 2 provided at the center of a plane of a flange-shaped fixing member 22.
A fixed shaft 23 is installed on the fixing member 2A, and an iron core 25 is fixed on the fixing member 22 by engaging an engagement hole 25H provided in the center with an engagement protrusion 22A.

Also, the protrusion 2 on which the magnetic disks 30A and 30B are mounted
6 and a yoke portion 27 for fixing the annular magnet 33, each of which is integrally fastened using a method such as caulking, has bearings 31 and 32 fitted into the engagement hole 26A, and the bearing 31 and the inner ring side of 32 is fixed to the shaft 23
By fitting into the rotating hub 28, the rotating hub 28 is connected to the fixed shaft 2.
3 is rotatably engaged.

The protrusion 26 has spacers 35A and 35B interposed on its outer circumferential surface to fit the first and second magnetic disks 30A and 30B, and a fixed disk 37 is screwed to the upper surface with screws 38 to prevent the magnetic field. Disks 30A and 30B
It is designed to be fixed.

Further, the yoke portion 27 is provided with a skirt portion 27A that protrudes downward along the outer periphery, and an annular magnet 33 is fixed to the inner peripheral surface of the skirt portion 27A.

Therefore, by engaging the rotating hub 28 at a position where the iron core 25 faces the annular magnet 33, a magnetic circuit is formed by the annular magnet 33 and the iron core 25, and by conducting a driving current to the iron core 25, the rotating hub 28 is rotated. The magnetic disks 30A and 30B are thereby driven to rotate.

Furthermore, the bearings 31 and 32 have a rubber-based sealing member that does not contain DOP (plasticizer), and are designed to reduce scattering of bearing grease and the like when the rotating hub 28 rotates.

Here, as shown in FIG. 2, on the upper side surface 25A of the iron core 25, there is provided an annular projection portion 26B (a first
A concave portion 25B having a circular planar shape is formed into which the lower end portion (FIG.) is loosely fitted.

This recess 25B is a gap formed by an outer peripheral surface 26C of the annular projection 26B and a step surface 25C of the recess 25B when the rotating hub 28 is engaged with the fixed shaft 23 via the bearings 31 and 32. 40 is approximately 0.2 (
(2) They are formed to have the following spacing, and the lower end surface of the annular protrusion 26B does not come into contact with the upper surface 25D of the recess 25B.

Therefore, when the rotating hub 28 rotates around the fixed shaft 23, the outer circumferential surface 26C of the annular protrusion 26B maintains a predetermined distance of approximately 0.2 [■] or less from the stepped surface 25C of the iron core 25. It is designed to rotate while

On the other hand, the gap 42 formed between the outer circumferential surface 27B of the yoke portion 27 and the inner circumferential surface 22B of the fixing member 22 is approximately 0.
．． 2 [simple] or less, and when the rotary hub 28 rotates about the fixed shaft 23, the predetermined interval is maintained.

Thus, in the motor 20, a labyrinth is formed in which the inner side (bearings 31 and 32) of the motor 20 is sealed from the outer side when the rotating hub 28 is rotationally driven by the gaps 40 and 42 formed at minute intervals. A sealing structure is formed.

In the above configuration, when the drive current is conducted to the motor 20 and the rotary hub 28 is rotationally driven, a labyrinth space is formed in which the pressure is lower than in other spaces in the gaps 40 and 42 which are formed at a minute interval. The inner side, where the bearings 31 and 32 are provided, is sealed against the outer side.

Therefore, it is possible to prevent dust caused by bearing grease generated in the bearings 31 and 32 from scattering to the outside from the gap 42, thereby preventing the magnetic disk 30A from scattering to the outside.
And it is possible to prevent foreign matter such as dust from adhering to 30B.

In this way, it is possible to prevent repeated errors from occurring when reading data from the magnetic disks 30A and 30B.

According to the above configuration, the first
By providing a labyrinth space (gap 40) and providing a second labyrinth space (gap 42) at a position away from the bearings 31 and 32, a sealing member using magnetic fluid as in the conventional case is provided. Without motor 20
The inside of the motor 20 (that is, the space in which the bearings 31 and 32 are provided) can be sealed from the outside, and the motor 20 can be made much thinner than conventional motors.

By using the bearings 31 and 32 provided with rubber-based seal members that do not contain DOP, generation of dust caused by bearing grease can be more effectively prevented.

Furthermore, by not providing a magnetic fluid sealing member, the mounting distance between the bearings 31 and 32 can be increased, thereby further improving the perpendicularity of the magnetic disks 30A and 30B to the fixed shaft 23. can.

In addition, according to the above-mentioned embodiment, a case was described in which a combination of the protrusion 26 and the yaw V part 27 was used as the rotating hub 28, but the present invention is not limited to this. It may be formed integrally.

Further, in the above embodiment, the upper surface 25A of the iron core 25
A recess 25B is formed in the step surface 25C of the recess 25B.
Although the case where the outer circumferential surface 26C of the annular protrusion 26B is opposed to each other at a predetermined interval to form the gap 40 (that is, the labyrinth space) has been described, the present invention is not limited to this. A convex step may be formed on the side surface 25A, and a protrusion may be provided on the lower surface of the rotating hub 26 to face the side surface of the step at a predetermined distance.

Further, in the above-described embodiments, the width of the gaps 40 and 42 is set to 0.2 (m) or less, but the present invention is not limited to this, and various other gap widths may be applied as necessary. can do.

Furthermore, in the above embodiment, the first labyrinth space (
Although the case where the gap 40) and the second labyrinth space (gap 42) are formed has been described, the present invention is not limited to this.
Only the first labyrinth space (gap 40) or the second labyrinth space (gap 42) may be formed.

Furthermore, in the above-described embodiments, a case has been described in which the present invention is applied to a motor that rotationally drives a magnetic disk, but the present invention is not limited to this, and can be applied to various other motors.

Effects of the Invention As described above, according to the present invention, a labyrinth space is formed between the rotating part and the fixed part of the motor, and the inside of the motor is sealed. It is possible to realize a motor with a sealed structure that can be

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a motor according to the present invention;
FIG. 2 is a perspective view showing the configuration of the recessed portion of the iron core, and FIG. 3 is a sectional view showing a motor using a conventional magnetic fluid sealing member. 1.20...Motor, 3.22...Fixing member, 8.28...Rotating hub, 10.25.
...Iron core, 12.33...Annular magnet, 2
5B/Old...Concavity, 25C...Step surface, 26B
...... Annular protrusion, 40.42... Gap.

Claims (1)

[Scope of Claims] In a motor having a fixed part and a rotating part rotatably engaged with the fixed part, a labyrinth space consisting of a minute gap is formed between the fixed part and the rotating part, and the motor A motor characterized in that the inside of the motor is sealed.