JPS61112547A - Disk drive motor - Google Patents

Abstract

PURPOSE:To prevent a rotor from laterally vibrating by rotatably engaging a rotary hollow sleeve provided at the center of a rotor side with a stationary shaft implanted to the center of the stator side through a radial fluid bearing and a thrust fluid bearing. CONSTITUTION:A stationary shaft 10 is implanted to the center of a base plate 6, a stator core 8 is engaged with the outer periphery of the projection 7 of the plate 6, and stator coil 9 is wound to form a stator. A yoke 4 and a field magnet 5 are mounted inside a spindle hub 2 of recess shape mounted on the outside with a plurality of magnetic discs 1, a rotary sleeve 3 opened in a hollow shape at the downside is implanted to the center of the recess to form a rotor. The stationary shaft 10 and the sleeve 3 are rotatably coupled through a thrust fluid bearing 11 and a radial fluid bearing 12. Thus, the rotor and the stator are prevented from laterally fluctuating at high speed rotation time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a disk drive motor suitable for driving a RA disk.

[Conventional technology]

A disk drive motor for rotating a magnetic disk belongs to brushless motors, and in the past, as seen in Japanese Patent Application Laid-Open No. 56-43263, a motor main body is built into a spindle hub on which a magnetic disk is mounted, and the entire motor is assembled into a brushless motor. There are some that are designed to be thin. Specifically, it is constructed as shown in FIG. 2, for example. That is, a rotor is configured mainly by a field magnet (102) on the inner circumferential surface of a circular cup-shaped spindle hub (101), and a stator is configured inside the rotor mainly by a driving filter (103). This is what I did. A spindle (104) protrudes from the center of the rotor side.
4) Is it the center of the stator side? This implanted sleeve (10
5) via a ball bearing (106).

A conventional disk drive motor is constructed as described above, and a rotating magnetic field formed by energizing the drive coil (103) generates torque in a fixed direction on the rotor, causing the rotor and spindle hub (1o1) to rotate. The magnetic position of the rotor is detected by a detection element such as a Hall element, and based on this, the control circuit distributes current to the drive coil (103) that generates the maximum torque.

[Problem that the invention seeks to solve]

In the conventional disk drive motor as described above, the spindle (104) is connected to the sleeve (105). Small ball bearing (106)
Since the pole of the ball bearing (106) is supported by the ball bearing (106), the vibration caused by the rolling P of the pole is caused by the spindle (106).
4) Rotation? In addition to this, there was a problem in that the reduction in the radial dimension was strongly restricted by the ball bearing (106).

The present invention was made in order to eliminate this problem, and to provide a disk drive motor in which the bearing element does not become a constraining factor for reducing the radial dimension, and which can rotate with less runout. purpose.

[Means for resolving interlude points]

The disk drive motor according to the present invention has a rotating sleeve on the rotor side and a fixed shaft on the stator side. Is it possible to rotate through a fluid thrust bearing and a fluid radial bearing? It is fitted with this.

[For Kui] In this invention, the rotating sleeve on the rotor side is connected to the fixed shaft on the stator side, a fluid thrust bearing, and a stationary radial bearing. Because it is fitted in a non-contact manner,
There is almost no runout of the bearing element, and there is little rotational runout.
Factors that limit the reduction of bearing elements in radial dimension? Konarin is very strong.

[Embodiments of the invention]

The disk drive motor as an embodiment of the present invention shown in FIG. 1 has a spindle hub (2) in the diameter of a circular, cup-shaped motor body in which a magnetic disk (1) is mounted. The assembly was designed to reduce the thickness, and is basically the same as the conventional example shown in Figure 2e. 71 That is, a rotating sleeve (3) with an open lower end is provided in the center of the spindle hub (2), and the outer circumferential surface of this rotating sleeve f3) and the inner circumferential side of the spindle hub (2) The rotor and the stator are arranged between the rotor and the circumferential surface.

The rotor consists of a yoke (4) attached to the inner peripheral surface of the spindle hub (2) and a cylindrical field magnet (
5), and the stator is fixed to the spindle hub (2).
) on the upper surface of the base plate (6) on the other side? It consists of a stator core (8) and a drive coil (9) mounted on the outer periphery of a protruding cylindrical portion (7). A fixed shaft (7hdc) is set upward in the center of the base plate (6), and the rotating sleeve (3) is connected to this fixed shaft α0.
It is fitted in. Rotating sleeve (3) & fixed shaft + 10) A thrust fluid bearing α is located between the end of the fixed shaft GO and the bottom of the rotating sleeve (3).
υ allows rotation between the inner circumferential surface of the rotating sleeve (3) and the outer circumferential surface of the fixed shaft body in a non-contact state due to the radial fluid bearing (2)? The supported hydrodynamic bearing element forms a pressure film of fluid between the sliding surfaces and pulls the sliding surfaces.
The amount of pressure generated to support the load of the pressure film depends largely on the viscosity of the fluid. In the figure, the reference numeral indicates the circuit board that constitutes the electronic circuit, α4)c indicates the Hall element fixed to the circuit board 03 and detects the position of the rotor magnet, and α9 indicates a part of the structure of the hydrodynamic bearing. , respectively show the grooves formed on the fixed shaft α*.

Thus, although the disc drive motor of this example rotates in a similar manner to a brushless motor, there is little wobbling of the spindle hub (2) due to the rotational V. This is because the rotating shaft (3) is supported not by a ball bearing but by a thrust fluid bearing (α) and a radial fluid bearing (6), whereas the fixed shaft (10) is supported by a thrust fluid bearing (α) and a radial fluid bearing (6). This is because magnetic disks (
1) can be rotated with extremely little vibration. Further, unlike ball bearings, the radial dimension is not defined, so it is easy to measure the overall radial dimension, and it is possible to construct a motor body that easily fits into the spindle hub (2).

〔Effect of the invention〕

As is clear from the above description of the embodiments, the disk drive motor of the present invention has a fixed shaft installed at the center of the stator side. Is it possible to rotate the rotating sleeve, which is inserted into the center of the rotating rotor on the outside of the stake, via a radial fluid bearing and a thrust fluid bearing? Since this structure does not include ball bearings in the rotating part, there is no runout component due to pole transfer due to rotor rotation, and the rotor has the advantage of smooth rotation with almost no runout. In addition, hydrodynamic bearings require smaller radial dimensions than ball bearings, and are more flexible in size, making it possible to reduce the overall radial dimension.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a disk drive motor according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional disk drive motor. figure? Here, (1) is a magnetic disk, (2) is a spindle hub, (3) is a rotating sleeve, is a fixed shaft, αη is a thrust fluid bearing,
(2) is a radial fluid bearing. Agent: Masuo Oiwa (and 2 others) L...Magnetic disk 2...Spindle hub 3...Rotating sleeve

Claims (1)

[Claims] A rotating sleeve protruding from the center of the rotor rotating on the outside of the stator is rotatably fitted to a fixed shaft installed at the center of the stator via a radial fluid bearing and a thrust fluid bearing. disk drive motor.