JPS58172954A - Spindle motor for disc memory - Google Patents

Abstract

PURPOSE:To reduce the rotary torque ripple by mounting a motor mechanism which has substantially equal functions and performances at both ends of a spindle, to which a magnetic disc memory is fixed, at a phase angle of approx. half of the rotating angle of unit pole. CONSTITUTION:Recording and reproducing transducers 3 are disposed corresponding disc 2 which is fixed to a rotational shaft 1, positioner assemblies 80, 80' of linear actuator type which positions and drive the transducers 3 are provided, and the shaft 1 is supported through bearings 4, 4' by housings 5, 5'. Then, motor assemblies 70, 70' of rotational shaft direct coupling type are respectively provided at both ends of the shaft 1, and a load torque which is necessary to ordinarily rotate the disc 2 is respectively shared by half by the motor assemblies 70, 70'. In this case, the assemblies 70, 70' are mounted at both ends of the shaft 1 at the phase angle of approx. half of the rotating angle of the unit pole with one to the other, and the apparent number of poles is increased, thereby reducing the rotary torque ripple.

Description

[Detailed description of the invention] Regarding structure.

Conventionally, as a spindle drive motor for a magnetic disk device, one drive motor is coupled to each spindle. This means that rotational torque is supplied from only one side of the spindle shaft, which causes uneven stress on the entire spindle, shaft runout, and unbalanced heat transfer, causing rotation of the magnetic disk. Differences in the amount of positional deviation in the radial direction between the spindles and the occurrence of ripples due to the spindle motor magnetic pole configuration are factors that can prevent improvements in recording performance.

The present invention improves the above-mentioned drawbacks and improves storage performance by incorporating two nearly identical electric motor mechanisms into both ends of a spindle to which a magnetic disk is fixed, with a phase difference in the rotational direction. The purpose is to provide disk devices.

According to the present invention, there are two sets of rotary shaft direct-coupled motor mechanisms that are mounted on a single rotary shaft and have substantially the same structural performance, and each motor has a rotating direction of the rotor and stator magnetic poles forming t+. As for the phase characteristics, a spindle motor for a disk storage device is obtained in which the two motors are shifted from each other by an angle of about half of the rotation angle constituting the respective motor unit magnetic poles to the rotation axis.

Next, embodiments of the present invention will be described with reference to the drawings.

Referring to FIGS. 1 and 2, the first embodiment of the present invention includes a recording disk 2 fixed to a rotating shaft 1, and a recording/reproducing transducer 3 disposed corresponding to the recording disk 2. and a linear actuator-type body 9 assembly 80 (80') 11111 for positioning and driving the recording/reproducing transducer 3, and a housing 5.5 that supports the rotary shaft 1 through bearings 4 and 4', respectively. ', and rotating shaft direct-coupled motor mechanisms (hereinafter referred to as spindle motor assembly) 70 and 70' attached to both ends of the rotating shaft 1, respectively.

The spindle assembly 70, 70' has an outer rotor type motor structure, in which a rotor magnetic pole 72 is fixed to the rotating shaft 1 via a rotating housing 71, and a rotor magnetic pole 72 is fixed to the housing 5 on the inside opposite to the rotor magnetic pole. Stator coil 73
is installed.

The spindle motor assemblies 70 and 70' receive controlled drive currents to maintain a constant rotational speed, generate approximately the same rotational torque, and each half shares the load torque required to steadily rotate the recording disk 2. . Because of this, the torque distribution in each bearing 4, 4' becomes almost symmetrical,
Furthermore, since the disk rotating shaft structure including the spindle motor assembly 70, 70' is also symmetrical at both ends of the rotating shaft 1, the heat generated in each part is evenly distributed.

Further, in this first embodiment, there are two rotor assemblies 70. (70') is the other motor mechanism 70', (7
0) with a phase difference of approximately half the unit magnetic pole rotation angle. This will be explained in detail in the second embodiment of the present invention.

Referring now to FIG. 3, a second embodiment of the present invention is a Heiner rotor type spindle motor assembly 170.170.
This disk storage device uses a rotary shaft 1, and includes a recording disk 2 attached to a rotating shaft 1, and spindle motor assemblies 170, 170' attached to both ends of the rotating shaft 1.

Spindle motor assembly 170. (1'ZO') E Sai No. 4
71 is fixed to the housing 5 as shown in the figure. a stator magnetic pole 173 (173') around which a stator coil is wound;
One trochanter magnetic pole 172 (17
2'). Stator magnetic pole 173. (173
') are each stator magnetic pole, 173a, 173b, 1
73c (173'a.

173'b, 173'c), etc., and a plurality of sets (four sets) of magnetic poles are provided for three-phase driving.

Both stator magnetic poles 173, 173' are each magnetic pole 173a.

173b, 173c and each magnetic pole 173'a, 173'b.

173'-c are attached to the rotational direction of shaft 1 at the same angle, but rotor magnetic pole 172 attached to shaft 1
, (172') are magnetic poles 172 a , 172 b ・
...(172' a, 172' b-) and ite,
Magnetic pole 1 of rotor magnetic pole 172 for α° between magnetic poles
72a and the magnetic pole 172'a of the rotary potato magnetic pole 172' are attached with a phase difference so that the rotation angle is β' (=1/2α゛).

Next, the operation of the second embodiment will be explained with reference to FIG. 5. Since the two spindle motor assemblies 170 (170') are installed with a phase difference of angle β°, the resultant rotational torque is Attenuation corresponding to pulsation (ripple) can be obtained.

That is, in FIG. 5, one spindle motor assembly 170 has magnetic poles 173a, 173b.

Since the torques are generated in the order of 173c, the pulsating torque generated from these torques has a waveform ta. Similarly, the other spindle motor assembly 170' has a magnetic pole 173'a.
, 173'b, and 173'c, these pulsating torques have a waveform tb. Therefore, the combined torque pulsating torque in the two spindle motor assemblies 170, 170' has a waveform t (a+b), which is the sum of waveforms ta and tb. Therefore, the total torque pulsating torque is the spindle motor assembly 170.
Since the pulsating torque tb of ' is substantially the same frequency component and the same magnitude as the pulsating torque ta of the spindle motor assembly 170, and is out of phase by 180 degrees, they cancel each other out and attenuate.

In this way, in this embodiment, the stator magnetic pole and rotor magnetic pole phase angles of one motor mechanism have a phase difference of approximately half the unit magnetic pole rotation angle of the other motor mechanism. It goes without saying that the stator or rotor is mounted on both ends of a rotating shaft (spindle), and the same effect can be obtained no matter how the stator or rotor is mounted.

In the first and second embodiments of the present invention, a linear actuator type assembly has been described as the positioner assembly, but similar effects can be obtained by using a rotary type actuator.

As explained above, the present invention increases the apparent number of magnetic poles by HIing motor mechanisms having almost the same functional performance at both ends of the rotating shaft with a phase angle that is approximately half the unit magnetic pole rotation angle. This has the effect of reducing rotational torque ripple and reducing device vibration source torque.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the first embodiment of the present invention, taken along the line nn', FIG. 2 is a cross-sectional view of the first embodiment taken along line n', and FIG. FIG. 3 is a diagram for explaining a disk rotation shaft torque ripple in an example. 1: Disk rotation axis (=spear V) > 2: Recording disk 3; Recording/reproducing transducer 4.4': Bearing 5.5': Housing 70.70', 170, 170': Spindle motor assembly 71.7 bits Two rotors/one housing 72.72': Rotor magnetic poles 73.73': Stator assemblies 173a, 173b, 173c, 173a'. 173b', 173c': Stator magnetic pole 80.80'
: Positioner assembly / ■ Fig. 2/70' 3 Fig.S Fig.

Claims (1)

[Claims] one or more recording disks fixed to a single rotating shaft;
A disk recording device using magnetic, optical, magneto-optical, or other recording formats whose main storage element is one or more recording or reproducing transducers positioned on the surface of the disk has approximately the same functionality and performance. It has two rotary shaft direct-coupled motor mechanisms, and the phase angle of the stator magnetic poles and rotor magnetic poles constituting one of the motor mechanisms is the unit magnetic pole rotation angle of the other motor mechanism. A spindle motor for a disk storage device, characterized in that the spindle motor is mounted on both ends of the rotating shaft with a phase difference of about half an angle.