JPH1186427A - Spindle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size in a height direction, to decrease the number of parts and to reduce an assembly cost by integrally molding a rotor yoke and a turn table by a rotor holder, thereby constituting a rotor. SOLUTION: The rotor holder 11 is made of a resin and has a flat disk surface 11b. A boss part 11a fitting to the central hole of a disk is projected in its central and a rotor pull-off preventive part 11c is projected at the rear surface. The rotor holder is constituted by integrally molding these parts. The rotor yoke 9 formed by working a galvanized steel sheet is adhered to the outer periphery of the rotor holder 11 and an annular magnet 10 magnetized to multiple poles is fixed to the inner peripheral part of the rotor yoke 9 facing the outer peripheral part of a stator core 1. The turn table 12 consisting of a SUS material is mounted atop the disk part 11b and an annular felt 18 is stuck to the outer peripheral part. The inner peripheral part of the boss part 11a is provided with an annular clamping magnet 14. The rotor 7 integrally constituted in such a manner is press fitted and fixed to the spindle 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a spindle motor used in a disk drive.

[0002]

2. Description of the Related Art Conventionally, a spindle motor has been used in a disk drive device such as a CD-ROM drive. FIG. 3 is a diagram showing a conventional spindle motor.
The surface of the stator core 1, which is formed by stacking plates mainly made of silicon steel sheet, is insulated by covering the surface with a resin, and a plurality of resin positioning pins 2 are provided below the stator core 1. Is provided with a projecting portion 3 over the entire periphery, and a projecting portion is provided above the projecting portion 3 toward the inner periphery. A plurality of salient poles are provided on an outer peripheral portion of the stator core 1, and a coil 4 is wound therearound. An inner peripheral portion of the stator core 1 is fixed to an outer peripheral portion of the bearing holder 5, and a spindle 8 is inserted into the inner peripheral portion of the bearing holder 5. And the bearing holder 5
A groove 6 is provided in an inner peripheral portion of the spindle 8 or an outer peripheral portion of the spindle 8, and a gap is filled with a fluid (in most cases, oil is used). doing.

The rotor 7 is press-fitted and fixed to a rotating spindle 8 by a fluid bearing. The rotor yoke 9 is mainly made of a galvanized steel plate, and is a multi-polarized ring at a position facing the outer peripheral portion of the stator core 1. A rotor-shaped magnet 10 is mounted, and a rotor detachment preventing portion 21 is formed above the rotor yoke 9 by outsert molding with resin.
The rotor detachment preventing portion 21 protrudes downward from the rotor yoke 9, and is provided with a protruding portion toward the outer periphery so as to engage with the protruding portion of the protruding portion 3 provided on the stator core 1.

A turntable 12 for mounting a disk (not shown) includes a centering 13 for positioning the disk on the inner circumference and a ring magnet 14 for disk clamping.
And is press-fitted and fixed above the spindle 8 separately from the rotor 7.

With the above configuration, even if an upward force for pulling out the turntable 12 is applied, the overhanging portion of the rotor slip-off prevention portion 21 and the overhanging portion of the protrusion provided on the stator core 1 are engaged. The rotor 7
Can be prevented.

[0006]

By the way, in recent years, CDs
-Disk drives, such as ROM drives, are required to be smaller and less costly.However, in the conventional structure, the rotor and the turntable are formed separately, and there is a problem that the dimension in the height direction cannot be reduced. there were. On the other hand, there is a problem that torsional resonance occurs between the rotor and the disk clamped to the turntable, which adversely affects the rotation control system of the motor. Further, the number of parts is large, the rotor structure is complicated, and the number of assembly steps is large, so that it has been difficult to reduce the cost.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a resin rotor holder 11 having a boss 11a for positioning a disk.
A disk mounting turntable 12 provided on a disk portion 11b below the boss portion 11a;
A rotor yoke 9 provided on the outer periphery of the rotor yoke,
A rotor 7 integrally formed with a rotation driving magnet 10 provided on the inner periphery of the spindle motor and fixed to a spindle 8; and a rotor protruding from the lower surface of the resin-made rotor holder 11. There is provided a spindle motor characterized in that ends thereof are formed so that a disengagement preventing portion 11c and a projecting portion 3 provided on an upper surface of a stator core 1 are engaged with each other.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spindle motor according to the present invention will be described below with reference to FIGS. For the sake of convenience, the same components as those shown in the above-described conventional example will be denoted by the same reference numerals.

The bearing holder 5 is vertically mounted on the stator 16 formed on the metal base substrate 15, and the inner peripheral portion of the stator core 1 formed by mainly laminating a silicon steel plate on the outer peripheral portion of the bearing holder 5 is press-fitted. It is fixed.
The stator core 1 is outsert by a resin 17 to insulate the surface, and a coil 4 is wound around a plurality of salient poles provided on an outer peripheral portion. The outsert resin 17 is integrally formed with pins 2 for positioning and fixing, and these pins 2 are fitted into holes of a metal base substrate 15 provided on the stator 16. A spindle 8 is inserted into a hole provided in the bearing holder 5, and a fluid is filled in an inner periphery of the bearing holder 5 or a groove provided on an outer periphery of the spindle 8, and the spindle 8 is rotatably inserted into the bearing holder 5. It is pivoted. Furthermore, the lower end of the spindle 8 is formed in a semicircular shape, and a thrust bearing is formed by a resin thrust 19 fixed to the resin bearing holder 5. Furthermore, a resin rotor holder 11 is press-fitted and fixed above the spindle 8.
In the rotor holder 11 made of resin, a boss 11a that fits into the center hole of the disk is formed at the center, and a flat disk surface 11b is formed below the boss.
On the back surface of b, there is provided a rotor detachment preventing portion 11c provided concentrically with the protruding portion 3 provided on the stator core 1. The rotor detachment preventing portion 11c has its tip extended to the outer peripheral side to form an overhang portion. The protrusion is engaged with the protrusion of the protrusion 3 provided on the stator core 1 to prevent the rotor from coming off.

A rotor yoke 9 formed by processing a galvanized steel plate is adhered to the outer periphery of a rotor holder 11 made of resin, and a multipolar magnetized ring-shaped magnet 10 is formed on the inner periphery of the rotor yoke 9 facing the outer periphery of the stator core 1. Is fixed. Further, a turntable 12 made of a SUS material is mounted on the upper surface of the rotor 7, that is, the disk surface 11b, and a ring-shaped clamp magnet 14 is provided on the inner peripheral portion of the boss portion 11a. Thus, a ring-shaped felt 18 for increasing friction with the disk and preventing the disk from spinning is attached.

The above-described clamp magnet 14 is magnetized radially in four poles, forms a magnetic circuit together with the turntable 12 formed of an iron-based material, and clamps the disk to fix it to the turntable 12.

A Hall element 20 for detecting the position of the rotor 7 is provided at an arbitrary position facing the lower end of the ring-shaped driving magnet 10.
Is attached. The rotor 7 is rotated by a magnetic field generated in the stator core 1 by applying a current to the coil 4 from a circuit separately provided by a signal of the Hall element 20 and a hydrodynamic bearing structure by the bearing holder 5 and the spindle 8.

[0013]

As described above in detail, according to the spindle motor of the present invention, since the rotor yoke and the turntable are integrated, the dimension in the height direction can be reduced, and the length of the spindle can be further reduced. Therefore, the frequency of the torsional resonance generated between the rotor yoke and the turntable is increased, and the influence on the control system of the motor is reduced. In addition, since the rotor pull-out prevention part and the turntable are integrally formed, the number of parts is reduced,
Since the structure of the rotor is simplified, it is possible to reduce the cost.

[Brief description of the drawings]

FIG. 1 is a view showing a spindle motor according to one embodiment of the present invention.

FIG. 2 is a sectional view showing a spindle motor according to one embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional spindle motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator core 3 Projection part 11 Rotor holder 11a Boss part 11b Disk part 11c, 21 Rotor detachment prevention part

Claims (2)

[Claims] 1. A resin rotor holder provided with a boss portion for positioning a disk, a disk mounting turntable provided on a disk portion below the boss portion, A spindle motor, wherein a rotor in which a rotor yoke provided on an outer periphery and a rotation driving magnet provided on an inner periphery of the rotor yoke are integrally formed is fixed to a spindle. 2. An end portion is formed so that a rotor disengagement preventing portion provided on a lower surface of the resin rotor holder and a projecting portion provided on an upper surface of the stator core are engaged with each other. The spindle motor according to claim 1, wherein