JPS62239380A - High-accuracy rotor device - Google Patents

Abstract

PURPOSE:To improve the rotational accuracy of a rotor device by providing an elastic pilot pressure means to a joint part between rotor component members, i.e., the component elements of a rotary assembly to produce the uniform force in the ambient direction vertical to a rotary shaft. CONSTITUTION:The joint gaps are secured at the joint parts between the inner ring of an upper bearing 3 and a colar 6, the colar 6 and a rotary shaft 2, a lower bearing 4 and the shaft 2 and between a rotor 11 of a DC motor and the shaft 2 respectively. Then the O-ring setting grooves are provided to the colar 6, the shaft 2 and the rotor 11 for insertion of O-rings 7a-7d into those gaps. Thus these gaps are kept even in their circumferential directions and therefore the center of mass of each member is coincident with the center of rotation. Then no unbalance of the mass is produced around the rotary shaft of the rotor as a whole despite the high-speed revolutions. This can avoid the drive caused by the swinging revolutions of the rotor.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to rotating body devices in general, and in particular to a high-precision rotating body suitable for rotating body devices that require high rotational precision such as spindles for magnetic disk drives. Regarding equipment.

[Conventional technology]

Generally, in a rotating body device, the unbalance around the rotation axis V button FE
4-F Hitoshio resembles Yuki hZ monichi? When high rotational precision is required, such as a spindle for a desk device, the performance of the device is determined by the degree of whirling. As described in the publication, by performing self-rotation processing after spindle assembly, the amount of unbalance around the rotation axis is reduced, and a spindle assembly with high rotational accuracy is obtained.

[Problem that the invention seeks to solve]

In a rotating body device, the unbalance around the rotation axis is largely caused by the assembly precision of each member constituting the rotating body, and this cannot be solved by the self-rotating process shown in the conventional example. This is because self-rotation machining only makes the static swing of the rotating body, that is, the outer shape, uniform around the rotation axis, and does not eliminate the unbalance of the mass around the rotation axis. The unbalance of mass around the rotation axis is mainly determined by assembly accuracy. When assembling a rotating body, there is a gap between the rotating body and the rotating axis, so if this gap is biased to 10,000 on either side, the mass around the rotating axis will be unbalanced, resulting in dynamic whirling during high-speed rotation. It emits vibrations.

In order to prevent dynamic whirling, it is possible to rotate the rotating body at high speed after completing the assembly, and to add adjustment masses to several places on the rotating body to reduce rotational synchronous vibration. However, with such a method, it is difficult to obtain a rotating body with sufficiently high precision, and the workability is also poor.

An object of the present invention is to solve this problem in conventional devices by a simple structure of the rotary assembly itself, and to provide a highly accurate rotary assembly.

[Means for solving problems]

The above object can be achieved by eliminating the misalignment of the fitting gaps between the members constituting the rotating part of the rotating assembly, and by distributing the quality -1 of the rotating part evenly around the rotating axis.

That is, it is sufficient to assemble the rotating body components so that their centers of mass all overlap the same point as the center of the rotating shaft. The above object can be achieved by inserting an elastic body such as an O-ring into the fitting gap in order to eliminate the deviation of the fitting gap.

[Effect]

When the elastic body is compressed and inserted into the fitting portion of the rotating body constituent members, the force that the elastic body attempts to combine is blocked by the rotating body constituent members, and elastic energy is accumulated. The elastic body itself tries to reach the lowest elastic energy state.
This means that the elastic body is subjected to uniform compressive stress in the gaps between the rotating body constituent members.

Therefore, if the fitting gap is biased to 10,000 on either side, the elastic body will have a different stress distribution along the circumferential direction, making it unstable. The constituent members of the rotating body are moved in a distributed manner, and as a result, the fitting gaps between the constituent members become uniform. That is, since the center positions of the constituent members coincide with each other, the center of mass of the rotating body as a whole coincides with the position of the rotation axis, and vibrations due to rotation do not occur even when rotating at high speed.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 shows the structure of a spindle for a magnetic disk device.
A hub 1 for fixing a magnetic disk (the magnetic disk is omitted) and a rotating shaft 2 are formed into one body by shrink fitting. Both ends of the rotating shaft 2 are rotatably supported with respect to the pace 5 by an upper bearing 3 and a lower bearing 4, and the rotating shaft 2
A rotor 11 of a motor is provided at one end of the rotor 11, which is inserted into a stator 12 and is energized to rotate the entire rotating body at high speed. Further, a thrust preload spring 10 is provided to increase the rigidity by applying an axial preload force to the upper bearing 3 and the lower bearing 4, and pushes the outer ring of the lower bearing 4 downward with respect to the pace 5.

Therefore, the radial preload spring 14 is applied to the lower bearing 4 so that the outer ring of the lower bearing 4 can move downward along the pace 5.
The structure is such that the outer ring of the Pace 5 is pressed into contact with the Pace 5. Further, the upper bearing 3 is connected to the washer 15 via the collar 6.
The inner ring is fixed to the rotating shaft 2 with tL and screws 8, and the outer ring is fixed to the pace 5 with adhesive. The inner ring of the lower bearing 4 is D
C motor loaf 11 together with screw 9 and washer 15b
The outer ring is fixed to the rotating shaft 2 at a position 5, and the outer ring is movable downward while being in contact with the pace 5.

Because of the structure described above, the engagement part between the inner ring of the upper bearing 3 and the collar 6, the engagement part between the collar 6 and the rotation shaft 2, the engagement part between the lower bearing 4 and the rotation shaft 2, and A fitting gap is provided between the rotor 11 of the motor and the rotation shaft 2 at the joint portion thereof. In this embodiment, Q +
9 ng 7a, 7b, 7c.

7d, and for this reason, the collar 6, the rotating shaft 2. and (2) A groove is provided for assembling the motor's rotor 11KO-ring. For example, FIG. 2 shows a cross section 13-15 taken perpendicular to the rotating shaft 2, and the 0-ring 7
C is pressed and inserted into the fitting gap between the inner ring of the lower bearing 7C and the rotating shaft 2.

By providing the O-rings 7α, 7b, 7c, and 7j in this way, the fitting gaps between each member are kept uniform in the circumferential direction by the elastic force of the O-9 ring, so the center of mass of each member is Everything coincides with the center of rotation, and even when rotating at high speed, the mass L of the entire rotating body is not balanced around the rotation axis, so vibrations due to whirling do not occur.

〔Effect of the invention〕

According to the present invention, it is possible to obtain a rotating body device with high rotation accuracy because it is possible to prevent whirling photography of the rotating body with a simple structure, and it is also possible to perform self-rotation processing and dynamic balance balancing after assembly. etc. can be omitted, making it easier to assemble the device.

[Brief explanation of drawings]

FIG. 1 is a spindle for a magnetic disk device embodying the present invention, and FIG. 2 is a partial sectional view of the spindle shown in FIG. 1, taken along line BB in FIG. 1...Hub, 2...Rotating shaft, 3...Upper bearing, 4
...Lower bearing, 5...Base, 6...Color, 7
a, 7b, 7c, 7j...0-ring, 8...screw, 9...screw, 10...thrust preload spring, 11.
... Rotor of DC motor, 12 ... Stator of second DC motor, 13 ... Cross-sectional position, 14 ... Radial calculation I calm

Claims (1)

[Claims] 1. In a rotating assembly that rotates around a rotating shaft that is rotatably supported by a support member by a rotational support means such as a bearing, the interlocking portion between the rotating body constituent members that are the constituent elements of the rotating assembly. A high-precision rotating body device, further comprising an elastic preload means for generating a uniform force in a circumferential direction perpendicular to the rotation axis.