JPH07194080A - Motor - Google Patents

Abstract

PURPOSE:To improve the space factor of a coil winding and besides, improve the work efficiency in manufacture of a motor, and cut down the cost by lowering the eddy current loss thereby reducing a drive current, and also, reducing the gap magnetic resistance and cutting the magnetic flux leaked from space. CONSTITUTION:Teeth poles 3 with a large area are made protrusively at the ends of the projections of a plurality of bar-shaped windings 2 projected radially with their base ends set on the center shaft 10, and magnets 6 are arranged through gaps 7 in the positions opposed to the teeth poles 3. The winding part 2 consists of one where the cross section is round or the corner is rounded, so the space factor of the corner winding improves. Moreover, many slits 4 are recessed at the teeth poles 3 jutted out largely, and eddy current loss and the core loss are sharply reduced, and also the magnetic flux leaked from space is cut.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet type small motor in general, a spindle motor and various micromotors, and more particularly to a motor having a high coil winding space factor and suitable for reducing eddy current loss.

[0002]

2. Description of the Related Art Various types of motors such as small magnet type motors and spindle motors have been conventionally used.
For D), the type schematically shown in FIGS. 13 and 14 is generally used. An annular bracket 9 is fixed to the stationary mounting base 8, and a central shaft portion 10 is formed at the center of the bracket 9. On the outer circumference of the central shaft portion 10, a stator core 100 having a large number of winding portions 200 protruding in the radial direction is fitted. The stator core 100 is shown in FIG.
As shown in FIG. 5, a plurality of steel plate laminations 11 are laminated, and a tooth pole portion 300 protruding in the circumferential direction is formed at the protruding end of the winding portion 200. The winding portion 200 and the tooth pole portion 300 are covered with an insulating coating film 15 as shown in FIGS. 13 and 14. In addition to the insulation, the coating is intended to prevent the wire from breaking during winding by softening the edges with an obtuse angle, and is applied by a method such as electrodeposition coating or powder coating. The stator coil 12 is wound around the winding portion 200.

On the other hand, the rotor magnet 6 on the rotating side is a ring-shaped member arranged so as to surround the outer circumference of the stator core 100, and is fixed to the rotor hub 13. The rotor hub 13 is pivotally supported on the central shaft portion 10 via a bearing 14. Inner surface of rotor magnet 6 and stator core 1
A gap 7 having an appropriate size is formed between the tooth pole portions 300 of No. 00. A disk-shaped magnetic disk 16 is fixed to the rotor hub 13 using a clamp 19. By supplying an electric current from the flexible printed board 17 provided on the bracket 9 side to the stator coil 12 side, the rotor magnet 6 side rotates.

[0004]

Generally, electric loss of a motor includes copper loss generated in a coil wound on the stator core 100, iron loss generated in the stator core 100, and mechanical loss caused by friction of a shaft. Copper loss is heat loss that occurs when current is supplied to the stator coil 12, and iron loss mainly consists of hysteresis loss and eddy current loss that occur in the stator core 100 when current is supplied. The copper loss is proportional to the square of the current supplied to the stator coil 12, the hysteresis loss is proportional to the frequency of the supply current, and the eddy current loss is proportional to the square of the frequency of the supply current.

Even in the conventional type motor, there are few problems when the motor rotation speed is low, but when the motor rotation speed is high, the frequency of the rotating magnetic field by the permanent magnet becomes large. Therefore, the iron loss becomes large, but generally, in the case of the laminated type stator core 100, a large eddy current loss occurs corresponding to the thickness of each layer. Here, when silicon is added to increase the specific resistance of the steel sheet in order to reduce the eddy current loss, there is a problem that the saturation magnetic flux density decreases in inverse proportion to the proportion of silicon. In addition, the eddy current loss in the motor magnetic circuit is concentrated on the tooth pole portion 300 having many magnetic flux harmonics.
In the conventional case, the coating film 1 is formed on the tooth pole portion 300.
5 is provided, the air gap is large, the area of the tooth pole portion 300 facing the rotor magnet 6 is not so large, and the magnetic resistance is high and the drive current (R
There is also a big problem in (UN current). Further, as shown in FIG. 12, there is a problem that a space leakage magnetic flux φ is generated around the tooth pole portion 300 and the gap magnetic efficiency is reduced. Further, the stator core 100 is formed by laminating the steel plate laminations 11, and the work process of laminating and aligning the laminations is required. Further, since the cross-sectional shape of the winding portion 200 is square, the coil winding space of the stator coil 12 is occupied. Not only is the rate low, but there is also a problem that the coil 12 is easily broken due to an acute edge.

The present invention solves the above-mentioned problems, and reduces the eddy current loss and the drive current while maintaining a high magnetic flux density, and improves the coil winding space factor,
Moreover, it is an object of the present invention to provide a motor that can improve work efficiency and reduce cost when manufacturing the motor.

[0007]

In order to achieve the above object, the present invention provides an armature in which a coil is wound around a core, a magnet and the like arranged so as to face the armature. In the provided motor, the core is composed of a large number of radial winding portions and tooth pole portions formed by projecting from the protruding ends thereof, and at least a slit is formed on the tooth pole portion opposite to the magnet. The winding portion has a cross-sectional shape with rounded corners. Further, according to the present invention, in a motor provided with an armature in which a coil is wound around a core and a magnet or the like arranged so as to face the armature, the core is provided with a large number of radial windings. And a tooth pole portion formed to project from the protruding end thereof, silicon Si is added by chemical vapor deposition or the like to at least the side of the tooth pole portion facing the magnet, and the winding portion is formed. Is characterized by having a rounded corner cross section.

[0008]

According to the present invention, the winding portion of the core is formed not only by lamination but also by a bar material and a bulk material having an integral structure,
It is basically based on the fact that a high magnetic flux density is retained in the tooth poles, and when using a bulk material, the cross-sectional shape is round or a corner with rounded corners. Since the steps of stacking and aligning are unnecessary and the edges of the coil do not stand, and the coil is wound closely to the winding portion, the coil winding space factor is improved. on the other hand,
The tooth poles of the core overhang from the periphery of the winding, increasing the area facing the magnet, reducing air gaps and magnetic resistance,
And the space leakage magnetic flux is cut. Further, the surface is modified by the formation of the slit or by the diffusion of silicon to the tooth pole portion, the eddy current loss is greatly reduced, and the gap magnetic efficiency can be improved. Also, by coating the winding part with an oxide film and forming it in a cross section such as a round shape, disconnection at the time of winding is prevented, and magnetic resistance is further reduced by plating the tooth pole part with magnetic metal. I can. When the frequency of the magnetic flux is high, the magnetic skin effect acts on the bulk material, so that the magnetic flux does not permeate into the bulk and the loss is suppressed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the present invention can be applied similarly when an armature rotates or stands still, an embodiment showing a HDD spindle motor in which the armature is stationary as a stator is shown in the drawings. It will be explained based on. 1 is a cut-away front view of this embodiment, FIG. 2 is an enlarged cut-away plan view of a line AA of FIG. 1 showing a structure around a stator core, and FIG. 3 is an enlarged line BB of FIG. 2 showing a tooth pole portion of the stator core. Front view,
4 is an enlarged side view taken along the arrow D in FIG. 3, and FIG. 5 is a line C- in FIG.
6 is an enlarged cut-away side view of C, FIG. 6 is an enlarged partially cut-away front view showing an embodiment of tooth pole portions having different slit shapes, FIG. 7 is an enlarged side view of arrow E of FIG. 6, and FIGS. FIG. 11 is an enlarged side view showing another embodiment of the slit shape of the pole portion, and FIG. 11 is an explanatory cut front view showing a cut state of the air leakage magnetic flux in this embodiment.

First, the overall schematic structure of the motor of this embodiment will be described with reference to FIG. An annular bracket 9 is fixed to the stationary mounting base 8, and a flexible printed circuit board 1 for supplying a current to the stator coil 12 is attached to the bracket 9.
7 are provided. The central shaft portion 1 is provided at the center of the bracket 9.
0 is fixed. The stator core 1, which will be described in detail later, is fitted on the outer periphery of the central shaft portion 10.

On the other hand, the rotor magnet 6 on the rotating side is arranged so as to surround the outer circumference of the stator core 1 via a gap 7 and is fixed to the rotor hub 13. The rotor hub 13 is pivotally supported on the central shaft portion 10 via a bearing 14. The magnetic disk 16 is fixed to the rotor hub 13 using a clamp 19. The illustrated dustproof cap 18 is for dustproofing the bearing 14.

As shown in FIGS. 1 and 2, a stator core 1 is formed on a winding portion 2 which is fixed to the outer periphery of a central shaft portion 10 at a base end side thereof and which radially protrudes, and a protruding end of the winding portion 2. It consists of a tooth pole part 3 that In addition, the stator coil 1 is provided in the winding portion 2.
2 is wound. The tooth pole portion 3 is arranged so as to face the inner circumference of the rotor magnet 6 via a gap 7, and a slit 4 is provided on the opposite side as shown in FIGS. 1 to 4.
This stator is made of pure iron cold-rolled material with a thickness of 1.4 mm and 3% silicon Si at the outer peripheral depth of the tooth pole of 0.5 mm
Are diffused by the CVD (chemical vapor deposition) method.

As shown in FIGS. 4 and 5, the winding portion 2 in this embodiment has a rectangular cross section and is made of pure iron or soft magnetic material. Further, as shown in FIG. 5, the corner portion is rounded by the arc surface 5 to eliminate the edge.
Further, although not shown, the winding portion may be covered with an oxide film or a coating layer, whereby smoothness of winding of the stator coil 12 and occurrence of disconnection at the time of winding are prevented, and high-speed winding is performed. Can be enabled.

As shown in FIGS. 1 to 4, the tooth pole portion 3 is made of a wide-area bulk-shaped angular member projecting vertically and circumferentially at the projecting end of the winding portion 2, and the winding portion is formed. It is formed integrally with 2. The slit 4 provided on the rotor magnet 6 side is composed of a large number of concave grooves formed in the horizontal direction in this embodiment. As described above, the slit 4 has a function of modifying the surface of the tooth pole portion 3. As a means for surface modification, a method of diffusing Si on the surface of the tooth pole portion 3 is also effective, but in the present embodiment, the slit 4 is also used. The depth of the slit 4 is appropriately set according to the magnetic circuit, but the slit 4 may be shallow so that the motor rotates at a high speed. Further, in order to further reduce the void resistance, the surface of the tooth pole portion 3 may be plated with a magnetic metal such as Ni.

Next, the operation of this embodiment will be described. The winding portion 2 of the stator core 1 is made of an R-shaped angular rod (which may have a circular cross-section) without edges, which does not require the steps of stacking and aligning as in the prior art, and is extremely easy to manufacture. Further, since the stator coil 12 is densely wound along the outer circumference of the winding portion 2, the winding space factor of the coil is improved.
In this case, the bobbin is loosely fitted to the winding part 2, the outer periphery of the bobbin is connected to the rotating body, and the bobbin is rotated, thereby enabling automatic winding. Generally, the magnetic resistance R is proportional to g / A.
Here, A is the area of the tooth pole portion 3 facing the rotor magnet 6, and g is the size of the gap 7. As described above, the tooth pole portion 3 of the present embodiment is made of a bulk and has a wide area, and if g is constant, the R value decreases as A increases. In addition, a large number of slits 4 are formed in the tooth pole portion 3 along with the diffusion of silicon, and a function of surface modification is added to reduce eddy current loss. As described above, both possession of high magnetic flux density and significant reduction of eddy current loss can be achieved. Further, the drive current (RUN current) can be reduced due to the decrease in magnetic resistance. On the other hand, as shown in FIG. 11, in this embodiment, the tooth pole portion 3 is formed so as to project from the protruding end of the winding portion 2, so that the space leakage magnetic flux is cut and the gap magnetic efficiency is significantly reduced (about 40). % Proved to be lower than that of the prior art).

Next, another embodiment of the tooth pole portion of the stator core 1 will be described with reference to FIGS. 6 and 7 show the tooth pole portion 3a in which the slit 4a is formed along the vertical direction (vertical direction). The same effects as those described above can be obtained by this embodiment as well.

FIG. 8 shows the slit 4b in the horizontal and vertical directions.
And shows a tooth pole portion 3b having a cross-shaped surface.

FIG. 9 shows a tooth pole portion 3c having a slit 4c inclined downward to the left.

FIG. 10 shows a tooth pole portion 3d having a slit groove 4d which is formed in a dogleg shape inclining to the left and to the right.

The tooth pole portions 3b and 3 shown in FIGS.
With c and 3d, the same effect as that of the tooth pole portions 3 and 3a can be obtained.

The shape of the tooth pole portion and the shape of the slit formed in the tooth pole portion are not limited to those in the above embodiment. Further, although the winding portion 2 has a square corner shape with rounded corners in the above embodiment, it may have a circular cross section such as a circular shape or an elliptical shape.

In the present case, another useful technique is surface modification by the CVD method. This makes it possible to use pure iron with low cost and high magnetic flux density. The application range in this case is not limited to bulk. Silicon can be diffused into an inexpensive iron plate to make these materials with high magnetic flux density and large loss practical.

[0023]

According to the present invention, the following remarkable effects are obtained. 1) By forming the toothed portion of the core in a bulk shape with a large area, the magnetic resistance of the gap is reduced, the eddy current loss is reduced, and the induced voltage is increased, and the induced voltage is returned to the original state for driving. The current can be reduced. 2) The coil winding space factor is improved and the coil is automatically wound at high speed by forming the winding part from a monolithic rod with a round shape or a rounded corner without using a laminated type. You can enable it. 3) By providing the slit on the magnet side of the tooth pole portion, the core loss is reduced, the rotation contributing component is increased, and the rotation efficiency of the motor can be improved. 4) By forming the protruding tooth pole portion, the space leakage magnetic flux is cut, and the gap magnetic efficiency can be significantly improved. 5) By coating the winding portion, the insulation of the stator coil can be facilitated and winding of the stator coil can be facilitated, and disconnection at the time of winding can be prevented. 6) By plating the tooth pole portion with a magnetic metal, it is possible to further reduce the magnetic current loss and obtain a rust preventive function. 7) It is possible to achieve both high magnetic flux density and low loss by using pure iron-based material with high magnetic flux density for the core and diffusing only the tooth poles of the material into silicon. 8) The lamination and the bulk material can be applied as the core, and when the bulk material is used, the characteristics that the loss does not reach the inside due to the magnetic skin effect can be utilized when the frequency of the magnetic flux change is high.

[Brief description of drawings]

FIG. 1 is a cut front view showing the entire structure of an embodiment of the present invention.

2 is an enlarged sectional plan view taken along line AA of FIG.

FIG. 3 is an enlarged partially cut front view taken along line BB of FIG.

FIG. 4 is an enlarged side view taken along the arrow D in FIG.

FIG. 5 is an enlarged cutaway side view of line C-C of FIG. 3.

FIG. 6 is an enlarged partial cutaway front view of a tooth pole portion of a stator core showing another embodiment of the present invention.

7 is an enlarged side view taken along the arrow E of FIG.

FIG. 8 is an enlarged side view showing an embodiment of tooth pole portions having different slit shapes.

FIG. 9 is an enlarged side view showing an embodiment of tooth pole portions having different slit shapes.

FIG. 10 is an enlarged side view showing an embodiment of tooth pole portions having different slit shapes.

FIG. 11 is a partially cut front view for explaining a cut state of the space leakage magnetic flux in the present embodiment.

FIG. 12 is a partially enlarged cutaway front view for explaining a state in which a space leakage magnetic flux is generated in a conventional stacked type stator core.

FIG. 13 is a partially cut front view showing a schematic structure of a conventional motor.

FIG. 14 is an enlarged cutaway plan view taken along the line FF of FIG.

[Explanation of symbols]

 1 Stator core 2 Winding part 3 Tooth pole part 3a Tooth pole part 3b Tooth pole part 3c Tooth pole part 3d Tooth pole part 4 Slit 4a Slit 4b Slit 4c Slit 4d Slit 5 Arc face 6 Rotor magnet 7 Gap 8 Mounting base 9 Bracket 10 Central shaft part 12 Stator coil 13 Rotor hub 14 Bearing 16 Magnetic disk

Claims (6)

[Claims] 1. An armature in which a coil is wound around a core,
A motor provided with a magnet or the like arranged so as to face the armature, wherein the core is composed of a large number of radial winding portions and tooth pole portions protruding from the protruding ends thereof. A motor is characterized in that a slit is formed at least on the side of the tooth pole portion facing the magnet, and the winding portion has a cross-sectional shape with rounded corner portions. 2. The winding portion has a circular cross section,
The motor according to claim 1, wherein the motor has a round shape such as an ellipse or a square shape with each corner rounded. 3. The tooth pole portion is made of a bulk-shaped soft magnetic material protruding from around the winding portion, and the slits are arranged in parallel in a horizontal direction, a vertical direction, an oblique direction and a composite direction thereof. The motor according to claim 1, comprising a plurality of groove portions having an appropriate depth. 4. The motor according to claim 1, wherein the winding portion is coated with an oxide film, and the slit side of the tooth pole portion is plated with a magnetic metal. 5. An armature in which a coil is wound around a core,
A motor provided with a magnet or the like arranged so as to face the armature, wherein the core is composed of a large number of radial winding portions and tooth pole portions protruding from the protruding ends thereof. Silicon Si is added by a chemical vapor deposition method or the like to at least the side of the tooth pole portion facing the magnet, and the winding portion has a cross-sectional shape with rounded corners. And a motor. 6. The motor according to claim 5, wherein the stator is formed of a lamination or a bulk core, and silicon Si is diffused by about 0.5 to 7% in a tooth pole portion thereof.