JPS5921248A - Drive motor for magnetic device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of characteristics of a drive motor by forming the vicinity of a shaft which engages a rotor having a permanent magnet of a nonmagnetic metal and reducing the influence of the variation in a magnetic field generated in a motor to the other through a main shaft. CONSTITUTION:A drive motor 50 has a stator 8, on which a coil 7 is wound on a core 6 out of the stator, mounted on a mounting frame 11, and is hermetically sealed by a cover 12 and a magnetic shield cover 12'. A rotor 100 has a rotor body 101, four permanent magnets 9 arranged outside the body and a bush 102 at the center. The body 101 is formed of a ferromagnetic material, the bush 102 is formed on nonferromagnetic material such as an austenite stainless steel or beryllium steel, and an engaging hole 102 of a main shaft and a keyway 104 are formed at the center. In this manner, the variation in the magnetic field of the motor 50 is interrupted by the bush 102, thereby eliminating the influence to the magnetic head and the magnetic disc at the opposite side to the main shaft inserted into the engaging hole 103, not shown.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention The present invention relates to improvements in drive motors for magnetic devices, particularly magnetic disk devices.

(2) Prior Art and Problems FIG. 1 shows a side view of a magnetic device for pivotally mounting a disk-shaped magnetic difference medium. In the figure, the main shaft (spindle) 2 passes through the center 18I5 of the housing 1 and the bearing 3
In the case of the figure, six magnetic media 4 are pivotally mounted on the main shaft 2 in the No-Ujifugu 1. A drive motor section 5 is constructed at the main shaft end of the housing l, which protrudes far beyond the main shaft 2. It consists of a rotor 10 having permanent magnets 9 which are solid-layered. The stator portion 8 is fixed to the lower mounting frame 11 of the housing 1 and is mechanically and magnetically sealed by a cover 12.

One side of the housing 1 is provided with a magnetic medium 4 for magnetically writing.
A swing arm assembly 14 containing a magnetic head 13 for reading is pivoted by 41415. A bearing 16 is interposed between the assembly 14 and the shaft 15.

A cylindrical shaft 11 extends from the F side of this assembly 14, and an oscillating motor 1B is connected to the outside of the housing 1.

This motor section 18 is also hermetically stacked on the housing 1 with a case 19 and a cover 20.

The above-mentioned magnetic device is connected to the drive motor section 4 by a control section 1i (not shown).
A drive current from the JJ Kaigen is applied to the wire 1 of the stator 8, and in response to the excitation of the drive magnetic field in the rotational direction, the permanent magnets 9 of the rotor 10 attract and repel, causing the rotor 10 to rotate in a predetermined direction. 1! applied like this! The current is a signal current of direct current (Do), and the drive motor and drive method are known techniques. ■□0”′F 7-z,y,,4″
(I&U, tEl11] 2 (D-gate, ': Rotation of the magnetic medium 4.

The oscillating arm assembly 14 is swung at a predetermined angle around the axis 1.5 by the driving current of the oscillating motor 18, but the magnetic head 13 at the tip of the arm is Moves in the radial direction in an arc with respect to the surface.

In such a magnetic device, a steady or fluctuating magnetic field generated by the motor is magnetically transmitted to the magnetic medium 4 and magnetic head 13 through a magnetic path passing through the main shaft 3 and shaft 15 made of iron-based materials. In order to prevent the influence of rumbling, a known magnetic seal 21.2'2 is installed in each part to shorten the magnetic recirculation. However, even with such a configuration, the current situation is that it cannot be said to be sufficient, especially with respect to the main shaft 2.

(3) Purpose of the Invention In view of the above problems, it is an object of the present invention to further reduce the induction of magnetic field coupling to the shaft in the motor section.

Il, , (4>, @Ming's configuration: Upper Hd, The summary of the present invention to achieve the object '□ is a rotor equipped with a permanent stone, and a rotor integrated with the rotor 1.
This is achieved by making at least the vicinity of the shaft portion of the rotor a non-ferromagnetic metal material in a magnetic device in which a magnetic medium is pivotally attached to the other shaft.

(5) Embodiments of the Invention Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings. Note that the a-air system in this embodiment is almost the same as that shown in FIG. 1, but the drive motor section is different, so only the core part will be illustrated and explained, and the other parts will be omitted.

Figure 2-Fuzenmei: (A) is a bottom view, (B) is a bottom view.
is a partially sectional side view. The main shaft 2 is not shown in the figure. In this drive motor section 50, a stator section 8 in which a wire ring 70 is wound around a fixed outer magnetic iron core 6 is fixed to a mounting frame 11, and the stator section 8 is sealed and sealed by a cover 12 and a magnetic shield cover 1z'l. rotor ioo
consists of a rotor main body 101, four Izumikyu magnets O arranged on the outside of the rotor main body 101, and a bushing 102 of the inner core.

Here, the rotor body 101 is made of iron-based metal, which is a ferromagnetic material, as in the past, but --l□02 has a strip (4'l Magnetic insulating materials such as austenitic stainless steel and beryllium □
Nante name. The coupling between the rotor tube 10'2 and the rotor body 101 is achieved by a person or the like by press-fitting, caulking, welding (welding), or utilizing thermal expansion. Of course, the connection □, which is used exclusively for pins, is also M. ' □ If the configuration of the drive motor described above is replaced with Fig. 1, the magnetic field generated in the drive system is not directly coupled and coupled with the main shaft 2, but is cut off by 4gl'o2''m, and only the induction 4- is generated. In addition to the effect of magnetic sheathing, the adverse effects on the magnetic medium and the magnetic yacht are greatly reduced.
□Although the common pipe part may be provided only near the shaft part, it can also be made to occupy the majority of the rotor or to be interposed in the middle part.

(6) Effects of the invention □ As described above, according to the present invention, the fitting part with the shaft part of the rotor of the drive motor is made of a non-ferromagnetic metal body.
1 The magnetic field from the morse section passes through the main axis.
1. Adverse effects on magnetic media, magnetic heads, etc.: A significant reduction in 0T performance results in 0T performance. This kind of thing is
:: It is composed in a place close to the origin of the world; its effect is remarkable.
I□Tun Brief explanation of the drawing □ @1m14aKi1tc01ft11N! ffmMil
ffl, g21fflU+, ,'1 In one embodiment of the invention, (A) is a bottom view, and (B) is a side view of the −, S cross section.
□

Claims (1)

[Claims] In a magnetic device including a rotor including a permanent magnet, a shaft integrated with the rotor, and a magnetic medium pivotally attached to the other shaft, all non-ferromagnetic metal is used at least in the vicinity of the shaft portion of the rotor. A magnetic device jL drive motor characterized by having a body.