JPH11346452A - Spindle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate assembling of a rotor in a stator by making the inner diameter of a hook-shaped part of a stopper section smaller than the outer diameter in the longitudinal direction of a pull-off preventive section, while making the inner diameter in the longitudinal direction of the stopper section larger than the outer diameter of a hook-shaped part of the pull-off preventive section, and dropping an adhesive between the outside of the stopper section and a coil. SOLUTION: This motor is provided with a pull-off preventive section 11, whose external shape is formed into a hook tapered toward the outside part of a rotor bushing 13 and a stopper section 3 whose external shape is formed into a hook toward the inner part of the rotor bushing 13. The inner diameter of the hook-shaped part of the stopper section 3 is made smaller than the outside diameter of a part of the pull-off preventive section 11 which extends in the longitudinal direction, while the inner diameter of a part of the stopper section 3 which extends in the longitudinal direction is made larger than the outer diameter of the hook-shaped part of the pull-off preventive section 11. Furthermore, an adhesive which becomes nearly the same in hardness as that of the stopper section 3 after it has hardened is dropped between the outside part of the stopper section 3 and a coil 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor for driving a disk such as a floppy disk drive CD-ROM drive, and more particularly to a structure for preventing a rotor from being mounted or removed.

[0002]

2. Description of the Related Art FIG. 7 is a cross-sectional view showing a conventional rotor slip-off prevention structure disclosed in Japanese Patent Application Laid-Open No. 9-247886. Reference numeral 8 denotes a rotating shaft that rotatably supports a turntable 24 that holds a disk (not shown). On this rotating shaft 8, a chucking magnet 22 that generates a suction force for attracting the disk to the turntable 24 is placed. The yoke 23 and the turntable 24 which are arranged as desired are integrally fixed.

[0003] Further, the turntable 24 is integrally provided with a rotor yoke 9 having a drive magnet 10 for generating a rotational force of a motor mounted on an inner periphery thereof. Further, a retaining member 25 having a cantilever portion 25a provided with a groove portion is fixedly provided at a thin portion 24a of the press-fitting portion of the turntable 24 into the rotary shaft 8, and constitutes the rotor 7. .

On the other hand, a core 1
Are disposed on the outer periphery of the housing 31 so as to face the drive magnet 10. A coil 4 that energizes the core 1 when energized is wound around the core 1. The core 1 also includes a bearing 29 and a bearing 30 that rotatably support the rotating shaft 8, a thrust bearing 19 that receives a force in the thrust direction of the rotating shaft 8, and an electric connection (not shown) that electrically connects the coil 4 from outside. It is fixed to the housing 31 together with the circuit board.

[0005] Further, a retaining member 2 is provided on the housing 31.
The groove portion 31 of the cantilever-shaped concave portion is opposed to the cantilever portion 25a having the groove portion 5 in the axial direction via a gap.
a, that is, the cantilever portion 25a and the groove 3
1a is an arrangement which can be engaged.

[0006] Also, in assembling the rotor 7, since the retaining member 25 is made of resin, when the rotor 7 is assembled, the cantilever portion 25 a of the retaining member 25 is shaped like a cantilever of the housing 31. Hit the recess,
It is inserted while flexing in the outer peripheral direction. Further, when the rotating shaft 8 and the thrust receiver 19 are pressed into contact with each other, the retaining member 25 and the groove 31a of the cantilever-shaped concave portion of the housing 31 face each other in the direction of the rotating shaft 8 via a gap. Becomes Here, when an impact force is applied to the motor itself, the force acts in a direction in which the rotor 7 comes off depending on the direction, and the rotor 7 tends to come off. But,
The cantilever portion 25a of the retaining member 25 and the groove portion 31a of the cantilever-shaped concave portion of the housing 31 facing the direction of the rotation axis via a gap are engaged with the cantilever portion 25a to prevent the rotor from coming off. doing.

In the above-described conventional example, since the cantilever portion 25a of the retaining member 25 is formed of resin or sheet metal, there is a possibility that the rotor 7 may come off the stator in terms of strength. Is high.

Therefore, a spindle motor shown in FIG. 5 can be considered. FIG. 5 is a sectional view showing another conventional example of the spindle motor. FIG. 4 is a plan view showing the spindle motor before the rotor is mounted.

The stator 16 is made of a metal base substrate 15 and is a Hall element 2 for detecting the position of the rotor 7 with the magnetic field of a ring-shaped driving magnet 10 attached to the inner periphery of the rotor yoke 9.
0 is located on the metal base substrate. The core 1 is formed by laminating silicon steel plates, and the inner periphery of the core 1 is fixed to the outer periphery of a brass bearing holder 5.
A resin 17 is outsert molded on the core 1 to insulate the coil 4 wound around the core 1. Bosses 2 inserted through positioning holes provided on the stator 16 are formed concentrically around the rotary shaft 8 at three locations by the resin 17 outsert molded on the core 1. Are formed concentrically around the rotation shaft 8 at three places. The tip of the stopper 3 is formed in a hook shape toward the inner periphery.

The bearing comprises a sintered oil-impregnated bearing 6 formed inside a bearing holder 5, a resin thrust 14, and a stainless steel washer 18, and supports the rotating shaft 8. A resin ring 21 is attached to the outer peripheral portion of the stopper portion 3 for restricting the stopper portion 3 from bending outward.

The rotor 7 comprises a rotor yoke 9 and a multipolar magnetized ring-shaped drive magnet 10 attached to the inner periphery of the rotor yoke 9, and is press-fitted and fixed to the rotating shaft 8 via a low bushing 13. In addition, row bushing 13
Is formed with a slip-off preventing portion 11.

FIG. 6 is a diagram showing a state in which the rotor 7 is assembled into the stator 16. (A) is a figure which shows the state which the stopper part 3 provided in the low bushing 13 and the stopper part 3 contacted, (b) is a figure which shows the state in which the stopper part 3 was pushed by the stopper part, (C) is a diagram showing a state where the rotor 7 is mounted on the stator 16.

According to FIG. 1, the stopper 3 is made of a resin, so that the stopper 3 is softer than the brass row bushing 13, and when the rotor 7 is assembled into the stator 16, the stopper 3 moves toward the outer periphery 6.5. It is pushed out at an angle of ° and returns to the original state after the rotor 7 is mounted.

[0014]

SUMMARY OF THE INVENTION Incidentally, Japanese Patent Application Laid-Open No.
In the conventional example disclosed in Japanese Patent No. 247886, as described above, since the retaining member is formed of resin or sheet metal, it is difficult to prevent the rotor 7 from coming off from the viewpoint of strength.

On the other hand, in the other conventional example, since the inner diameter of the stopper portion 3 is smaller than the outer diameter of the stopper portion 11, once the rotor 7 is assembled into the stator 16, it cannot be removed. However, since the stopper portion 3 made of resin alone may bend toward the outer periphery, the resin ring 2 may be used to reinforce this.
1 was mounted on the outer periphery of the stopper portion 3. However, there is a problem in that the resin ring requires assembly accuracy, and thus the cost of parts and assembly is high. In addition, there is a problem that the resin ring 21 makes it difficult to reduce the thickness. Further, since the height of the coil 4 wound around the core 1 is not constant, it is difficult to mount the resin ring 21. At this time, it is conceivable to obtain the strength by thickening the stopper portion 3 without using the resin ring 21.
When the stopper portion 3 is made thick, the core 1 becomes large to secure a space for winding the coil around the core 1, and it becomes difficult to reduce the size of the motor.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a rotor yoke 9, a driving magnet 10 fixed to the rotor yoke 9, and a rotating shaft rotatably supporting the rotor yoke 9. Rotor 7 including
A core 1 that faces the drive magnet 10 and generates torque for rotating the rotor 7; an insulating resin 17 that covers the outer periphery of the core 1; And a stator 16 including a coil 6 wound around the rotating shaft 8 and a bearing 6 for supporting the rotating shaft 8, and extends in the longitudinal direction of the rotating shaft 8 downward from the rotor yoke 9 and is concentric. A pull-out preventing portion 11 which is formed over substantially the entire circumference and has a hook-like shape whose outer side is tapered toward the outer circumference;
A stopper portion 3 extending in the longitudinal direction of the rotary shaft 8 upward from the upper portion thereof, formed concentrically at a plurality of locations, and further forming a hook shape toward the inner periphery; The inner diameter of the hook-shaped portion of the stopper portion 3 is smaller than the outer diameter of the portion extending in the longitudinal direction of the stopper portion 11, and the stopper portion 3 is larger than the outer diameter of the hook-shaped portion of the stopper portion 11. The adhesive 12 whose inner peripheral diameter of the portion extending in the longitudinal direction is large and whose hardness after hardening is substantially equal to the hardness of the stopper portion 3 is dropped between the outside of the stopper portion 3 and the coil 4. A spindle motor is provided.

[0017]

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. The same components as those described above are denoted by the same reference numerals, and a description thereof will be partially omitted. FIG. 1 is a perspective view showing a state of a spindle motor before mounting a rotor, and FIG. 2 is a sectional view showing an embodiment of a spindle motor according to the present invention.

The stator 16 is provided with a bearing holder 5 containing a sintered oil-impregnated bearing 6 mounted vertically on a metal base substrate 15, and the inner periphery of the core 1 is press-fitted and fixed to the outer periphery of the bearing holder 5. The core 1 is formed by laminating silicon steel plates, and an insulating resin 17 is outsert-formed around the outer periphery to wind the coil 4. This resin 1
7, a positioning boss 2 serving as a rotation stopper for the core 1 when attached to the stator 16 is formed on the stator 16 side, and the stator 16 is provided with a positioning hole through which the positioning boss 2 is inserted. . On the upper side of the resin 17, a stopper portion 3 that is concentric with the rotation shaft 8 as a center is provided. Further, a Hall element 20 for detecting the position of the rotor 7 and a circuit board (not shown) are mounted on the metal base board 15.

The rotor 7 is formed of a rotor yoke 9 made of a galvanized steel plate and a rotary bushing 13, and a ring-shaped drive magnet 1 is provided on the inner periphery of the rotor yoke 9.
0 is fixed. The rotating shaft 8 is held in a radial direction by a sintered oil-impregnated bearing 6 mounted on an inner peripheral portion of the bearing holder 5. The rotating shaft 8 has a semicircular end on the stator 16 side, forms a thrust bearing by a resin thrust 19 fixed to the bearing holder 5, and is held in the axial direction.

A current is applied to the coil 4 by a circuit (not shown) based on a signal detected by the Hall element 20, and the magnetic field generated in the core 1 and the ring-shaped driving magnet 1
0 rotates the rotor 7 supported by the sintered oil-impregnated bearing 6.

Further, the low bushing 13 corresponding to the stopper portion 3 is made of brass, and the rotor 7 is prevented from coming off by the come-off preventing portion 11 extending to the outer peripheral portion. The slip-out preventing portion 11 which comes into contact with the stopper portion 3 has a tapered outer peripheral portion, so that it can be easily mounted on the stator 16.

At this time, the stopper portion 3 and the detachment preventing portion 11
In consideration of the above-mentioned size, the inner peripheral diameter of the protruding portion forming the hook shape of the stopper portion 3 is made smaller than the outer peripheral diameter of the portion extending in the longitudinal direction of the pull-out preventing portion 11, and the hook shape of the pull-out preventing portion 11 is reduced. It is necessary to make the inner peripheral diameter of the portion of the stopper portion 3 extending in the longitudinal direction larger than the outer peripheral diameter of the projecting portion.

In the spindle motor having such a configuration, a UV curable adhesive is dripped and cured on the outside of the stopper portion 3 and on the upper surface of the coil 4 before the rotor 7 is mounted. If the adhesive 12 filled between the outside of the stopper 3 and the coil 4 is made to have substantially the same hardness as the stopper 3 after curing, the strength of the stopper 3 is increased, and the stopper 3 falls down outward. Since it is difficult to prevent the rotor from coming off, it is possible to enhance prevention of the rotor from coming off.

Even if the force F shown in FIG. 2 acts on the rotor 7, the stopper portion 3 is less likely to be deformed to the outer peripheral side. In the conventional example, the pull-out strength of the rotor 7 when the ring 21 is not provided is about 6N, but the pull-out strength of the rotor 7 in this embodiment is improved to about 20N, and is substantially equal to the pull-out strength when the ring 21 is attached. The effect can be obtained, and the cost can be reduced because only the cost of the adhesive is sufficient.

However, if the viscosity of the adhesive is low, the adhesive permeates into the coil 4 before it is cured, and it is considered that a sufficient effect cannot be obtained. Therefore, as a result of the study, it is desirable to use a UV-based adhesive having a kinematic viscosity of 5000 to 8000 cm ² / s as an adhesive dropped between the outside of the stopper portion 3 and the coil 4.

Next, the mounting operation of the rotor 7 on the stator 16 will be described with reference to FIG. FIG. 4A is a diagram showing a state in which the stopper portion 3 provided in the low bushing 13 is in contact with the stopper portion 3, and FIG. 4B is a diagram showing a state in which the stopper portion 3 is pressed by the stopper portion. And
(C) is a diagram showing a state where the rotor 7 is mounted on the stator 16.

According to the drawing, the stopper 3 is formed of resin, and the UV adhesive dropped between the outside of the stopper 3 and the coil 4 is hardened to substantially the same hardness as the stopper 3. Therefore, although it is softer than the brass rota bushing 13, it has sufficient strength,
When the rotor is assembled into the stator 16, the stopper portion 3 is pushed out toward the outer periphery at an angle of 6.4 °, and returns to the original state after the rotor 7 is mounted.

The stopper 11 of the low bushing 13 has a taper of 24 ° with respect to the rotating shaft 8. The smaller the taper angle is, the better. However, if the taper angle is reduced, the length of the slip-off preventing portion 11 is required, and it is difficult to reduce the thickness of the motor. On the other hand, if the taper angle is increased, the motor can be made thinner. However, when the rotor 7 is assembled into the stator, the stopper portion 3 is chipped or gallinged, so that sufficient rotor disengagement strength cannot be obtained. Therefore, when the taper angle is about 10 ° to 45 °, chipping or galling of the stopper 3 is less likely to occur, and when the taper angle is about 24 °, it is most stable.

[0029]

As described above in detail, according to the spindle motor of the present invention, the rotor is easily mounted on the stator by providing a taper in the pull-out preventing portion provided on the low bushing. Angle from 10 ° to 4
By setting the angle to 5 °, chipping or galling of the stopper portion is less likely to occur, and the device can be made thinner. Furthermore, by dropping an adhesive between the outside of the stopper portion provided on the stator and the coil, and hardening the same hardness as the stopper portion, the pulling strength of the rotor is enhanced, and
Cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state of a spindle motor before a rotor is mounted.

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

FIG. 3 is a sectional view showing an operation of mounting a rotor in the spindle motor according to the present invention.

FIG. 4 is a sectional view showing another conventional example of a spindle motor.

FIG. 5 is a plan view showing a state before mounting a rotor in another conventional example of a spindle motor.

FIG. 6 is a sectional view showing a mounting operation of a rotor in another conventional example of a spindle motor.

FIG. 7 is a sectional view showing a conventional spindle motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core 2 Boss 3 Stopper part 4 Coil 5 Bearing holder 6 Sintered oil-impregnated bearing 7 Rotor 8 Rotating shaft 9 Rotor yoke 10 Drive magnet 11 Pull-out prevention part 12 Adhesive 13 Low bushing 14 Thrust 15 Metal base substrate 16 Stator 17 Resin 18 Washer 19 Thrust bearing 20 Hall element 21 Ring 22 Chucking magnet 23 Yoke 24 Turntable 24a Thin section 25 Retaining member 25a Cantilever section 29, 30 Bearing 31 Housing 31a Groove section

Claims (1)

[Claims] A rotor including a rotor yoke, a driving magnet fixed to the rotor yoke, and a rotating shaft rotatably supporting the rotor yoke; and a torque facing the driving magnet and rotating the rotor. A spindle motor comprising: a core having an outer periphery of the core; an insulating resin covering the outer periphery of the core; a coil wound around the outer periphery of the core via the insulating resin; and a stator including a bearing for supporting the rotating shaft. It extends in the longitudinal direction of the rotation shaft downward from the rotor yoke, is formed concentrically over substantially the entire circumference, and further,
A pull-out preventing portion having an outer side tapered and shaped like a hook toward the outer periphery, extending in the longitudinal direction of the rotating shaft from an upper portion of the insulating resin upward, and formed concentrically at a plurality of locations; A stopper portion having a hook shape toward the inner periphery, wherein the inner diameter of the hook portion of the stopper portion is smaller than the outer diameter of a portion of the stopper portion extending in the longitudinal direction,
The inner peripheral diameter of a portion extending in the longitudinal direction of the stopper portion is larger than the outer peripheral diameter of the hook-shaped portion of the detachment prevention portion, and the hardness after curing between the outside of the stopper portion and the coil is A spindle motor wherein an adhesive having a hardness substantially equal to a hardness of a stopper portion is dropped.