JPH0578184U - Rotary drive - Google Patents

Abstract

(57) [Abstract] [Purpose] A labyrinth seal that is easy to assemble and does not leak dust such as dust generated in an electric motor to the periphery of a magnetic disk without requiring complicated processing technology and processing accuracy. Provided is a rotary drive device including a portion. [Structure] A hub base 24 holding a magnetic disk D is supported by a shaft 20 fixed to a frame 21,
The annular flange portion 24b facing the inner peripheral surface 25a of the annular recess 25 formed in the hub is integrally formed with the hub base 24. A labyrinth seal portion 29 is formed at 24c so as to project in a direction intersecting the axis of the shaft 20.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rotation drive device for holding and rotating the center of a disk-shaped magnetic disk, for example.

[0002]

[Prior Art]

 Conventionally, as such a rotation driving device, for example, there is a rotation driving device 1 for driving a magnetic disk as shown in FIG. 3 (see Japanese Patent Publication No. 61014/1989).

The rotary drive device 1 includes a hub base 2 which holds a disk-shaped magnetic disk (not shown).

The hub base 2 has a top plate 2 a whose center is connected to the upper end of a rotating shaft 3 extending in the vertical direction that intersects with the magnetic disk, and a top plate 2 a directed downward from the peripheral edge of the top plate 2 a. Of a cross-section having a peripheral wall portion 2b that is protruded and fitted with a magnetic disk, and an annular flange portion 2c that is bent outward from the lower end portion of the peripheral wall portion 2b in the horizontal direction and holds the bottom surface of the magnetic disk. It is formed in a hat shape.

A rotor yoke 4 made of a magnetic material is fixed to the lower portion of the rotary shaft 3. The upper part of the rotary shaft 3 is held on the upper part of the hollow bracket 8 via bearings 6 and 7. Furthermore, a spring 9 for preload is wound around the upper portion of the rotary shaft 3 so as to be located between the bearings 6 and 7.

The hollow bracket 8 is integrally formed with a flange portion 2c of the hub base 2 and an electric motor substrate 10 which is opposed to the flange portion 2c of the hub base 2 while intersecting with the rotary shaft 3. A stator core 13 is provided below the hollow bracket 8 so as to face the permanent magnet 11 fixed to the peripheral surface of the rotor yoke 4 and to wind a stator winding 12. The rotor yoke 4, the permanent magnets 11, the stator windings 12, and the stator core 13 are covered with a bottom cover 14 formed in a bottomed cylindrical shape.

On the other hand, a labyrinth seal portion 15 composed of a plurality of protrusions is formed in a portion of the hub base 2 opposed to the flange portion 2c and the motor substrate 6 along the rotary shaft 3 and a part of the protrusions alternately face each other. Has been done.

In the rotary drive device 1 configured as described above, the hub base 2 is rotated at a constant high speed in a state where the magnetic disk is fitted on the outer peripheral surface of the hub base 2 and applied onto the surface of the magnetic disk. Information is recorded or read by changing the state of magnetization of the concentric recording medium formed on the magnetic powder.

[0009]

[Problems to be solved by the device]

 By the way, in the rotation drive device configured as described above, the labyrinth seal portion 15 for blocking dust such as dust is provided in a part of the motor board 6 and the hub base 2 in a direction along the axis of the rotation shaft 3. Since it is composed of projections that are projected alternately, the axial gap d is not only in the axial direction, but also in the axial position d of the bearings 6 and 7 in the direction intersecting the axial line. There is a problem in that the gap accuracy varies due to the deviation, the processing accuracy of the hub base 2 and the electric motor substrate 6.

The present invention has been made in view of the above circumstances, and is easy to assemble, and dust such as dust generated in the electric motor is easily generated in the vicinity of the magnetic disk without requiring complicated processing technology and processing accuracy. It is an object of the present invention to provide a rotary drive device including a labyrinth seal portion that does not leak to the inside.

[0011]

[Means for Solving the Problems]

 In order to achieve the object of the present invention, a shaft having a partly protruding portion is fixed, and a frame in which an annular recess is formed around the axis of the shaft is provided, and the frame is opposed to an inner peripheral surface of the annular recess. A hub base for holding a magnetic disk integrally formed with an annular flange portion having a peripheral surface, and a protrusion in a direction intersecting with the axis line on one of the inner peripheral surface of the frame and the peripheral surface of the flange portion. The gist of the present invention is to provide a labyrinth seal section that is provided.

[0012]

[Action]

 In such a configuration, the frame is formed with an annular recess centered on the axis of the shaft, and the hub base for holding the magnetic disk has an annular flange portion having a peripheral surface facing the inner peripheral surface of the recess. Is formed integrally, and the labyrinth seal part protruding in the direction intersecting the axis is formed on either the inner peripheral surface of the frame or the peripheral surface of the flange part. Not only is it easier to process the labyrinth seal while maintaining good performance, but it is also easier to assemble the frame and hub base.

[0013]

【Example】

 Next, an embodiment of the rotary drive device of the present invention will be described with reference to FIGS.

In FIG. 1, the rotation driving device A includes a frame 21 to which a lower end of a shaft 20 having an upper part projected is fixed, and a magnetic disk which is held on the projecting upper part of the shaft 20 via bearings 22 and 23. And a hub base 24 for holding D.

An annular recess 25 centered on the axis of the shaft 20 is formed in the frame 21. A stator core 27, which is located in the annular recess 25 and has a winding 26, is fixed to the frame 21.

The hub base 24 is integrally formed on its inner peripheral surface 24 a with an annular flange portion 24 b to which a rotor magnet 28 facing the stator core 27 is fixed.

The outer peripheral surface 24 c of the annular flange 24 b faces the inner peripheral surface 25 a of the annular recess 25. Further, a labyrinth seal portion 29 having a chevron male screw shape is formed on the outer peripheral surface 24c so as to project in a direction intersecting the axis of the shaft 20.

It should be noted that the groove formed by the thread of the labyrinth seal portion 29 is continuous downward, and guides the air around the magnetic disk D along with the rotation of the hub base 24 into the annular recess 25. Is set to. As a result, dust such as dust generated in the electric motor rarely leaks to the periphery of the magnetic disk D, and dust adhesion to the magnetic disk D is prevented.

In the above-described configuration, the rotation drive device A rotates the hub base 24 at a constant high speed in a state where the magnetic disk D is fitted on the outer peripheral surface of the hub base 24 and applies the magnetic disk D to the surface of the magnetic disk D. Information is recorded or read by giving a change in the state of magnetization of the concentric recording medium formed on the magnetic powder thus formed.

At this time, dust such as dust generated in the electric motor is generated by the labyrinth seal portion 29 guiding the air around the magnetic disk D into the annular recess 25 as the hub base 24 rotates. Is prevented from leaking to the surrounding area.

By the way, although the labyrinth seal portion 29 is formed on the hub base 24 and the shape thereof is formed as a male screw in the above embodiment, the invention is not limited to the above. For example, as shown in FIG. 2, the labyrinth seal portion 39 may be formed on the frame 21 side, or the same effect as above can be obtained even if the labyrinth seal portion 39 is formed in a Hirayama male screw shape. . 2, the same components as those in FIG. 1 are designated by the same reference numerals as those in FIG. 1 and their description is omitted.

[0022]

[Effect of the device]

 As described above, in the rotary drive device of the present invention, a frame having a partly protruding shaft fixed and an annular recess centered on the axis of the shaft is provided, and A hub base for holding a magnetic disk integrally formed with an annular flange portion having a peripheral surface facing the peripheral surface, and one of the inner peripheral surface of the frame and the peripheral surface of the flange portion. Since it has a labyrinth seal protruding in a direction intersecting with the axis, it is easy to assemble, and dust such as dust generated in the electric motor is required without requiring complicated processing technology and processing accuracy. Does not leak around the magnetic disk.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an example of a rotary drive device of the present invention.

FIG. 2 is a sectional view of an essential part showing another example of the rotary drive device of the present invention.

FIG. 3 is a sectional view of an essential part showing a conventional rotary drive device.

[Explanation of symbols]

 D magnetic disk 20 axis 21 frame 24 hub base 24b annular flange 24c outer peripheral surface (peripheral surface) 25 annular recess 25a inner peripheral surface 29 labyrinth seal portion

Claims (1)

[Scope of utility model registration request] 1. A frame, to which a shaft, a part of which is projected, is fixed and which has an annular recess centered on the axis of the shaft,
A hub base for holding a magnetic disk integrally formed with an annular collar portion having a peripheral surface facing the inner peripheral surface of the annular recess,
A rotary drive device comprising a labyrinth seal portion projecting in a direction intersecting with the axis on one of the inner peripheral surface of the frame and the peripheral surface of the collar portion.