JPH0574182U - Spindle motor - Google Patents

Abstract

(57) [Abstract] [Purpose] A stator provided with a winding, and a rotor rotatably rotatably supported so as to face the stator through a gap, and the rotor including an annular permanent magnet and a yoke. A spindle motor having a frequency generator for detecting the speed of a rotor and a detector for detecting a specific position of the rotor, the spindle motor having no small magnet for detecting the specific position of the rotor The purpose is to get. [Structure] In order to achieve the above object in the present invention,
The position detection magnetic pole is directly formed on the outer peripheral surface of the frequency generator permanent magnet that is fixed to the outer peripheral surface of the rotor yoke and has its axial end surface magnetized for speed detection. To achieve.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a spindle motor, and more particularly to a spindle motor used as an external storage device such as a computer.

[0002]

[Prior Art]

 FIG. 3 is a plan view showing the structure of a conventional spindle motor, FIG. 4 is a cross-sectional view, and 1 is a printed wiring board serving as a motor base, 2 is a stator core, and 3 is a stator. Windings, 4 bearing brackets, 5 bearings, 6 rotor shaft, 7 rotor boss, 8 rotor yoke, 9 permanent magnet of motor, 10 chucking portion of desk, 11 spring, 12 Is a permanent magnet for a frequency generator, 13 is a power generation winding of the frequency generator, 14 is a small magnet for detecting a specific position, 15 is a position detector, and 16 is a drive pin portion. The spindle motor shown in FIGS. 3 and 4 detects the magnetic pole positions of the permanent magnets 9 of the opposing motors in the plurality of stator windings 3 wound around the stator iron core 2 and sequentially energizes the stator windings 3 to make them permanent. A device that rotates a rotor equipped with a magnet 9 to rotate a floppy desk (not shown) mounted on the chucking portion 10 of the desk, and a frequency generator to control the rotation speed to a constant level. A small magnet 14 for position detection and a position detector 15 are provided for the purpose of detecting a specific position of a floppy disk driven by a rotor.

[0003]

[Problems to be solved by the device]

 In the conventional spindle motor shown in FIGS. 3 and 4, in addition to the permanent magnet 12 for the frequency generator fixed to the outer circumference of the rotor yoke 8, a specific position is detected on the outer circumference of the permanent magnet 12. The small magnet 14 is fixed, and in this configuration, the permanent magnet 12 for the frequency generator and the small magnet 14 are prepared as separate parts, and it is necessary to fix the small magnet 14 at a predetermined position, which is costly. There was a problem that it would be high. An object of the present invention is to obtain a spindle motor that can detect a specific position without using a small magnet for position detection.

[0004]

[Means for Solving the Problems]

 The spindle motor of the present invention achieves its object by forming magnetic poles corresponding to small magnets for position detection directly on the outer peripheral surface of a permanent magnet for a frequency generator.

[0005]

[Action]

 Since the magnetic poles are directly magnetized to the outer peripheral surface of the permanent magnet for the frequency generator, it is not necessary to attach a small magnet as a separate component.

[0006]

【Example】

 1 is a plan view showing the structure of an example of a spindle motor according to the present invention, and FIG. 2 is a sectional view of the example of FIG. The difference from the spindle motor according to the prior art shown in FIGS. 3 and 4 is that the outer peripheral surface of the permanent magnet for the frequency generator does not have a small magnet for position detection, and it is directly attached to the outer peripheral surface of the permanent magnet for the frequency generator. A magnetic pole corresponding to a small magnet is formed.

In FIGS. 1 and 2, reference numeral 12 ′ is a magnetic pole for position detection, which is magnetized into two poles N and S along the outer peripheral surface of the permanent magnet 12.

The position where the magnetic pole 12 ′ for detecting a specific position is magnetized is determined by detecting the magnetic flux of the magnetic pole 12 ′ when the drive pin portion 16 and the hub (not shown) of the floppy disk are properly chucked. 15 and set the signal to indicate a particular location on the floppy desk. This allows the magnetic pole 12 'to be provided at an arbitrary position by changing the position of the detector 15.

[0009]

[Effect of the device]

 Since the spindle motor according to the present invention has the above structure, it is not necessary to provide a small magnet as a separate component on the outer peripheral surface of the permanent magnet for the frequency generator, and the number of components and man-hours can be reduced. There is an effect that can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view of an example of a spindle motor according to the present invention.

FIG. 2 is a sectional view of the spindle motor of the example shown in FIG.

FIG. 3 is a plan view of an example of a conventional spindle motor.

FIG. 4 is a sectional view of the spindle motor of the example of FIG.

[Explanation of reference symbols] 1: Printed wiring board as a base 3: Stator iron core 3: Stator winding 4: Bearing bracket 5: Bearing 6: Rotor shaft 7: Boss 8: Rotor yoke 9: Motor permanent Magnet 10: Desk chucking part 11: Spring 12: Frequency generator permanent magnet 12 ': Position detection magnetic pole directly magnetized to the outer periphery of the frequency generator permanent magnet 13: Frequency generator power generation winding 14 : Small magnet 15: Position detector 16: Drive pin

Claims (1)

[Scope of utility model registration request] 1. A rotor provided with a winding, and a rotor rotatably supported so as to face the stator with a gap interposed therebetween, the rotor including an annular permanent magnet and a yoke, and the speed of the rotor. In a spindle motor equipped with a frequency generator for detecting the rotor and a detector for detecting a specific position of the rotor, the rotor motor is fixed to the outer peripheral surface of the rotor yoke, and its axial end surface is magnetized for speed detection. A spindle motor characterized by being directly magnetized for position detection on the outer peripheral surface of a permanent magnet for a frequency generator.