JPH09121492A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the air gap in a motor containing an iron core by subjecting the iron core obtained by laminating plate members to electrodeposition coating, installing an armature of polymeric material member thereon, and thereafter winding a coil around it. SOLUTION: A herringbone groove for radial bearing is formed on a sleeve 7 and a spiral group groove for a thrust bearing is formed on a thrust plate 8 to form a dynamic pressure fluid bearing. Thus a shaft 6 is supported by dynamic pressure through fluid. An iron core 1 is subjected to electrodeposition coating, and a thin electrodeposition film is formed on the entire surcumference of the iron core 1. An insulator 4 obtained by molding polymeric material, such as polybutylene terephthalate, is inserted into the iron core 1 with an electrodeposited coating, and a wire 5 is wound around it to form a coil assembly. The coil assembly is crimped onto the inside wall of a bracket 3 at the outer radius.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating and rustproofing treatment for an iron core of a motor in which plate members are laminated.

[0002]

2. Description of the Related Art In recent years, there is a demand for downsizing and higher performance of OA equipment, audio equipment, and video equipment, and in response to this, it is common to improve the performance by narrowing the gap between the motor iron core and the magnet. Target. In such a motor (for example, a magnetic disk drive motor), it is necessary to take measures against the occurrence of rust on the iron core.

Further, a motor used in a humid environment or a special environment such as outer space also needs a countermeasure against rusting of the iron core.

On the other hand, a resin-molded insulator, which is an insulating member for the winding and the iron core, is used to reduce the thickness of the motor. However, the molded insulator alone may rust the fracture surface of the outer periphery of the core. In recent years, motors (for example, motors for magnetic disk drive devices and polygon mirror rotation drive devices) are generally subjected to insulation treatment only by electrodeposition coating on the iron core, but insulation by electrodeposition coating alone is not sufficient. Cases are emerging.

An example of insulation and rustproofing of the iron core of a motor in which plate-like members are laminated, which has been generally used in the past, will be described below.

(Conventional Example 1) FIG. 4 is a structural view of a conventional brush motor having an iron core in which plate members are laminated.
Shows the armature winding assembly of the motor of FIG.

A conventional motor will be described below with reference to the drawings. 4 and 5, 101 is an iron core formed by stacking plate-like members, 102 is a shaft, 103 is a resin-molded insulator, 104 is a magnet, 105 is a winding wire,
106 is a frame, 107 is a commutator terminal block, 108 is a brush, 109 is a bracket, and 110 and 111 are metal.

An iron core 101 in which plate-like magnetic materials are laminated is fixed to a shaft 102, and a resin-molded insulator 103 resin-molded into a substantially same shape as the iron core 101 is used as an iron core 101.
, And the commutator terminal block 107 is press-fitted onto the shaft 102.

Here, the iron core 101 is only subjected to an insulating treatment by the resin molding insulator 103, and the outer peripheral surface of the iron core 101 facing the magnet 104 is not subjected to any treatment.

Next, the winding wire 105 is wound around the iron core 101, the energized portion of the winding wire 105 is attached to a predetermined position of the commutator terminal block 107, and a soldering process is performed to make an armature winding assembly of the motor. Make a solid.

On the other hand, the metal 110 is fixed to the central portion of the frame 106, and the magnet 104 is attached to the inner peripheral side of the cylindrical portion of the frame 106.
04 is magnetized. A metal 111 is fixed to the central portion of the bracket 109, and a brush 108 is attached to the outer peripheral side of the bracket 109. Subsequently, the shaft of the armature winding assembly is attached to the metal 110 and 11
The bracket 109 is attached to the frame 106 while being inserted into the motor 1 to complete the motor.

(Conventional Example 2) FIG. 6 is a structural diagram of a motor for a magnetic disk drive, showing another example having an iron core in which conventional plate-like members are laminated. Another conventional example will be described below with reference to the drawings. In FIG. 6, 113 is an iron core formed by stacking plate-like members, 114 is a shaft, 115 is a powder coating film, 116 is a magnet, 117 is a winding wire, and 118 is a wire.
Is a rotor hub, 119 is a bracket, and 120 is an anticorrosion coating film.

A ball bearing for rotatably supporting the shaft 114 is fixed to the hole of the central cylindrical portion of the bracket 119 by adhesion. On the outer periphery of the central cylindrical portion of the bracket 119, a winding 117 is wound around the iron core 113 coated with powder and is attached to the central cylindrical portion of the bracket 119. The shaft 11 is provided at the center of the rotor hub 118.
4 is press-fitted, and the magnet 116 is adhesively fixed to the inner peripheral surface of the rotor hub 118.

Iron core 113 formed by stacking plate-like members
A powdery insulating material made of a resin material such as epoxy is directly sprayed on the surface of the iron core, and then the insulating material is subjected to heat treatment to form an insulating layer. The outer peripheral surface of the iron core 113 facing the inner periphery of the magnet 116 is not the powder coating film 115,
It is covered with a rust-preventive coating film 120 formed by brushing a varnish such as Knittor.

(Conventional Example 3) FIG. 7 shows another conventional example in which the conventional motor shown in FIG. 6 is subjected to electrodeposition coating for surface treatment of the iron core in order to reduce the thickness and improve the output characteristics. FIG. 7 (a) is a top view of the iron core of a motor with electrical coating in a conventional example, FIG.
7 (b) shows a winding assembly wound on a winding wire, and FIG. 7 (c) shows a winding wound around an iron core treated by electrodeposition. FIG.
In the above, reference numeral 123 is an iron core formed by laminating plate-like members, 124 is a winding wire, and 125 is an electrodeposition coating film.

Iron core 12 formed by laminating plate-like magnetic materials
The surface of No. 3 is subjected to cationic electrodeposition coating, and the magnet facing surface of the outer periphery of the iron core 123 is also covered with the electrodeposition coating film, so that the brush painting work of the varnish as shown in FIG. 6 is unnecessary.

[0017]

In a motor in which no treatment is applied to the outer peripheral surface of the iron core, such as the brushed motor of Conventional Example 1, the surface of the contact material of the brush or commutator is cleaned to be excellent. To maintain commutation performance, clean the armature after it has been assembled. For this reason, punch oil is also removed when the iron core is pressed, so that the press fracture surface of the outer peripheral surface of the iron core facing the magnet is easily rusted in a humid environment.

In addition, when the armature winding assembly is handled by a worker who touches the outer periphery of the iron core, rust may occur on the outer periphery of the iron core if left in a high humidity environment. This makes it difficult to handle. Further, since the gap between the iron core and the magnet of the brushed motor is generally about 0.5 mm to 0.8 mm, foreign matter attached to the gap between the iron core and the magnet does not cause the motor rotation abnormality. It was However, recently, in order to improve the motor characteristics, it becomes more necessary to narrow this gap, and there is a great possibility that abnormal rotation of the motor due to rust will occur in a special environment.

Further, in the magnetic disk drive motor of Conventional Example 2, a rust preventive coating film is formed by brush coating on the outer peripheral surface of an iron core formed by laminating plate-shaped magnetic materials, and windings are wound. The surface to be coated is coated with a powder coating film. Since the thickness of the anticorrosion coating film is relatively large and the variation is large, there is a problem in that the gap between the motor iron core and the magnet cannot be narrowed to improve the performance.

In Conventional Example 3, since the electrodeposition coating film serves not only for rust prevention but also for insulation of the winding, the film thickness is as thick as 50 to 150 μm in a general small motor. Therefore, the air gap must be increased by the film thickness,
The characteristics cannot be improved sufficiently.

When using a wire having a large wire diameter,
Tension at the time of winding is applied to the iron core more than the strength of the electrodeposition coating film, resulting in many insulation defects, and it is difficult to automate the wire processing of the winding end, and the number of man-hours for wire processing is large. It was Further, many paints used to secure the insulation between the iron core and the windings only by electrodeposition coating contain tin, and increasing the thickness of the electrodeposition coating film increases the amount of tin. Therefore, in a magnetic disk drive or the like, there is a problem that reliability is lowered by the gas generated from tin.

It is an object of the present invention to solve the above problems and to provide an excellent motor having an iron core which is compatible with the narrowing of the air gap and has an insulating treatment and a rust preventive treatment.

[0023]

The present invention provides the following means in order to achieve the above object. (1) An iron core laminated with plate-like members is subjected to electrodeposition coating treatment, and an insulating layer of a polymer material member is provided thereon to wind a winding. (2) An iron core having laminated plate-like members is subjected to a rust preventive treatment by a means other than painting, and an insulating layer of a polymer material member is provided thereon to wind a winding. (3) The insulating layer of (1) or (2) above is formed of a resin molded product. (4) An iron core laminated with plate-like members is subjected to baking coating treatment, and further insulated with a resin molded product of a polymer material, and wound with a winding wire.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view of a spindle motor for a magnetic disk drive according to a first embodiment of the present invention. FIG. 2 shows a winding assembly. In FIGS. 1 and 2, 1 is an iron core formed by stacking plate-like members, 2 is an electrodeposition coating film, 3 is a bracket, 4 is a resin-molded insulator resin-molded into substantially the same shape as the iron core 1, and 5 is a winding wire. 6 is a shaft, 7 is a sleeve, 8 is a thrust plate, 9 is a hub,
Reference numeral 10 is a rotor frame, and 11 is a magnet.

The bracket 3 includes a flange portion 31, an outer peripheral wall portion 32 located inside the flange portion 31, an annular bottom surface portion 33 formed in a lower inner portion of the outer peripheral wall portion 32, and an inner bottom surface portion provided on the bottom surface portion. It has a peripheral wall portion 34. This inner wall 3
A cylindrical sleeve 7 is attached to the inside of 4,
Further, a thrust plate 8 is fixed to the end of the sleeve 7. A herringbone groove of a radial bearing is formed in the sleeve 7, and a spiral groove groove of a thrust bearing is formed in the thrust plate 8 to form a hydrodynamic bearing, and the shaft 6 is hydrodynamically supported by a fluid. . Iron core 1 is coated with an electrodeposition coating composition as shown in (Table 1).
An electrodeposition coating film 2 having a thickness of about 20 μm is spread over the entire outer peripheral portion of the iron core 1.

[0027]

[Table 1]

Polybutylene terephthalate (abbreviated as PBT) is applied to the iron core 1 coated with electrodeposition.
The insulator 4 formed by molding a polymer molding material such as is inserted, and the winding 5 is wound on the insulator 4 to form a winding assembly as shown in FIG. This winding assembly is caulked and fixed to the outer peripheral side of the inner peripheral wall of the bracket 3.

The hub 9 is cup-shaped and comprises a disc receiving surface 41 and a cylindrical portion 42 for regulating the inner diameter of the disc.
A rotor frame 10 is caulked and fixed to the hub 9 on the side opposite to the disk receiving surface 41 in the axial direction. A cylindrical magnet 11 having N poles and S poles alternately magnetized in the circumferential direction is fixed to the inner peripheral surface side of the rotor frame 10. The shaft 6 is fixed to the central portion of the hub 9, and the rotor frame 10 and the magnet 11 are fixed near the disc receiving surface 41 to form a rotor portion as a whole.

The operation of the disk drive device constructed as above will be described below. The hub 9
A magnetic disk (not shown) is mounted on the disk receiving surface 41. The rotor part and the bracket 3
In the motor including the above, a magnetic field is generated in the salient poles of the iron core 1 by the current supplied to the winding 5, and a torque is generated between the magnetic field magnet 11 facing the iron core 1 to generate the torque. It is generally called a radial type brushless motor that rotates a rotor portion. Therefore, the magnetic disk clamped on the hub 9 also rotates as the rotor section rotates.

When the shaft 6 rotates, a dynamic pressure is generated through the oil by the action of a herringbone groove provided in the inner cylindrical portion of the sleeve 7, and the shaft 6 floats and rotates without contact. Further, also in the thrust direction, the shaft 6 rotates on the thrust plate 8 in a non-contact manner by the action of the spiral groove formed on the thrust plate 8.

Here, an example of the step of subjecting the iron core 1 to electrodeposition coating will be described below. When a water-soluble or water-dispersible paint is put in a bath, the iron core 1 is immersed in the bath, an electrode is attached to the conductive portion of the iron core 1 to be coated, and an electric current is applied between the iron and the counter electrode attached to the bath, electric charge is generated. The resin particles having the particles move to the iron core 1 by electrophoresis and are deposited. After washing this with water, it is fixed to the iron core 1 at a high temperature.

By controlling the composition, temperature, and energization conditions of the bath to appropriate levels, it is possible to easily control the thickness of the coating film and to obtain an electrodeposition coating film with less variation, and to manage a tolerance of ± 5 μm with a film thickness of 10 μm. . The outer periphery of the iron core 1 is also the electrodeposition coating film 2
However, the gap between the magnet 11 and the iron core 1 (hereinafter referred to as an air gap) is 1/2 as compared with a general air gap if the thickness of the electrodeposition coating film 2 is controlled.
The motor performance can be improved because the size can be made small. Further, since the electrodeposition coating film 2 is attached to the outer peripheral portion of the iron core 1, the rust preventive treatment by the varnish on the outer periphery of the iron core 1 is unnecessary. Generally, in the vicinity of the end of the iron core 1, the film thickness of the electrodeposition coating film 2 is thinner than the other parts. Therefore, when the winding is wound around the iron core coated only by electrodeposition, the tension of the winding is increased. If it is applied to the electrodeposition coating film 2 in excess of the film strength, insulation failure is likely to occur near the end of the iron core 1. Therefore, the iron core 1 was thinly electrodeposited and rust-proofed.
The insulation failure can be prevented by inserting the insulator 4 and winding the winding through the insulator 4.

Particularly when the winding diameter is large, the effect of the present invention is remarkable because a large tension is required during winding.

Further, with this configuration, the electrodeposition coating film can be made thin, so that a tin-free coating material can be used. Therefore, especially in the magnetic disk drive,
When the motor of the present invention is used in a device in a hermetically sealed state, when a paint containing tin is used, the problem that gas generated from tin is adsorbed on the magnetic disk and the reliability is lowered is solved.

(Second Embodiment) FIG. 3A shows an iron core 20 in which plate-like members according to a second embodiment of the present invention are laminated,
As a rustproofing treatment by means other than painting, a sectional view of a state where plating 21 is applied is shown. The plating 21 is preferably electroless nickel plating which is excellent in plating thickness accuracy and which is generally used for a motor hub of a magnetic disk drive, and which has an excellent rust preventive effect. Further, by inserting an insulator obtained by molding a polymer molding material such as polybutylene terephthalate (abbreviated as PBT) and winding a winding through the insulator, insulation is obtained as in the first embodiment. Defects can be prevented. Further, since the electroless nickel plating can have a thickness of 2 to 3 μm,
It is possible to improve the motor performance by narrowing the air gap of the motor.

When rust preventive treatment other than coating is performed by chemical conversion treatment such as manganese phosphate chemical conversion treatment, low temperature black dyeing treatment, high temperature black dyeing treatment, ferro zinc treatment, steam treatment, etc., electrodeposition coating is carried out. Since the film thickness can be made smaller than in the case of (1), the air gap of the motor can be narrowed and the motor performance can be further improved. Further, the same effect can be obtained even if the insulator is integrally formed with a rust-prevented iron core.

FIG. 3B shows an iron core 22 in which plate-like members are laminated.
An example in which an insulating member is integrally molded with polyacetal resin or the like after being subjected to zinc chromate plating or the like is shown.
Reference numeral 23 is an integrally molded insulating member.

(Third Embodiment) A third embodiment of the present invention will be described below.

An iron core formed by laminating plate-like members is baked and rustproofed, a resin insulator is inserted on the iron core, and a winding is wound through the insulator. Compared with the case of electrodeposition coating, there is less deterioration of coating, the coating process is simple, and conventional coating equipment is possible, so the processing cost is low.

[0041]

As is clear from the above description, the present invention
When the anticorrosive treatment of the iron core laminated with plate-shaped members is performed by electrodeposition coating, the air gap can be reduced to about 1/2 of the general size by controlling the coating film thickness. Can be improved. Further, since the outer peripheral portion of the iron core is also covered with the electrodeposition coating film, the rust preventive treatment by the varnish on the outer periphery of the iron core becomes unnecessary. In addition, insert an insulator into the iron core that has been rustproofed by applying a thin electrodeposition coating,
By winding the winding through this insulator, it is possible to prevent insulation failure due to tension during winding. In particular, when the winding diameter is large, a large tension is required during winding, so that the effect of the present invention is remarkable.

Further, with this configuration, the electrodeposition coating film can be made thin, so that a tin-free coating material can be used. Therefore, especially in the magnetic disk drive,
When the motor of the present invention is used in a device in a hermetically sealed state, when a paint containing tin is used, the problem that gas generated from tin is adsorbed on the magnetic disk and the reliability is lowered is solved.

Furthermore, manganese phosphate chemical conversion treatment, low temperature black dyeing treatment,
When chemical conversion treatment such as high temperature black dyeing treatment, ferro-zinc treatment or steam treatment is performed, the film thickness can be made thinner than that of electrodeposition coating, so the motor air gap can be narrowed and the motor performance can be further improved. .

Further, when baking coating is applied as rust preventive treatment for the iron core, the deterioration of the coating is less than that of the electrodeposition coating, the coating process is simple, and conventional coating equipment is possible.
Processing cost is low.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a motor for a magnetic disk drive using an iron core of a motor coated with electrodeposition according to a first embodiment of the present invention.

FIG. 2 (a) is a top view of a wire core assembly in which a winding is wound around an iron core of a motor according to the first embodiment of the present invention; and (b) an iron core of a motor according to the first embodiment of the present invention. Cross section of wire core assembly with windings

FIG. 3A is a sectional view of a plated iron core according to the second embodiment of the present invention. FIG. 3B is a resin insulator integrally molded product on the plated iron core according to the second embodiment of the present invention. Showing

FIG. 4 is a sectional view of a conventional small motor.

FIG. 5 is a diagram showing a winding assembly of a conventional small motor.

FIG. 6 is a cross-sectional view of a conventional magnetic disk drive motor.

FIG. 7 (a) is a top view of an iron core of a motor to which electrodeposition coating is applied in the conventional example. FIG. 7 (b) is a view showing a winding assembly having windings in the motor. Figure wrapped around an iron core that has been painted

[Explanation of symbols]

 1,20,101,113,123 Iron core 2,125 Electrodeposition coating film 3,109,119 Bracket 4,23,103 Insulator 5,105,117,124 Winding 6,102,114 Shaft 7 Sleeve 8 Thrust plate 9 , 118 hub 10 rotor frame 11, 104, 116 magnet 21 plating 22 plated iron core 31 flange portion 32 outer peripheral wall portion 33 bottom surface portion 34 inner peripheral wall portion 41 disc receiving surface 42 cylindrical portion 106 frame 107 commutator terminal block 108 brush 110 , 111 Metal 115 Powder coating film 120 Anti-rust coating film

Claims (4)

[Claims] 1. An armature obtained by subjecting an iron core having laminated plate-shaped members to an electrodeposition coating treatment, and providing an armature of a polymer material member or a stator insulating layer on the iron core, and then winding a winding. Motor with a stator. 2. An armature or a fixed structure in which an iron core laminated with plate-like members is rust-proofed by means other than painting, an insulating layer of a polymer material is provided on the iron core, and then a winding is wound. Motor with child. 3. A motor having an armature or a stator according to claim 1, wherein the insulating polymer material is a resin molded product. 4. A motor having an armature or a stator in which winding is wound by subjecting an iron core formed by laminating plate-shaped members to baking coating treatment, and further insulated with a resin molding of a polymer material.