KR100901192B1 - Stator and manufacturing method for the same - Google Patents

Abstract

A stator and a method of manufacturing the same are disclosed. The stator includes a stator core and a cut formed in the direction of the center of the stator core such that a cutting surface is in contact with a plurality of teeth extending inwardly of the stator core and the stator core between adjacent teeth. It can be carried out efficiently and the number of teeth can be increased, so that the magnetic flux density between the magnet and the stator can be increased to increase the torque constant of the motor.

Stator, coil, winding, cut

Description

Stator and manufacturing method for the same

The present invention relates to a stator and a method of manufacturing the same.

Among the many electric motors, brushless DC motors, which are widely used in recent years, include laser beam scanner motors for laser printers, motors for hard disk drives (HDDs), and optical disk drives such as compact disks (CDs) or digital versatile disks (DVDs). It is widely used as a driving source for spindle motors that require precision, such as a motor. In particular, spindle motors used in hard disk drives require high rotational precision, and thus, fluid dynamic bearings having high rotational accuracy are generally used.

However, the hydrodynamic bearing has the characteristic that the friction torque increases as the driving speed increases or the clearance of the hydrodynamic bearing decreases, and as a result, the efficiency of the brushless DC motor is reduced.

1 shows a spindle motor for a hard disk drive employing a conventional hydrodynamic bearing. Referring to FIG. 1, a conventional spindle motor for a hard disk drive includes a base 10, a sleeve 12, a shaft 20, and a hub 24.

The stator 31 is provided in the center of the base 10, and the stator coil 14 is provided in the slot portion of the stator 31. The sleeve 12 is fixed to the base 10, and a hollow portion is formed at a central portion thereof, and a shaft 20 is rotatably installed inside the hollow portion. A bearing gap is formed between the shaft 20 and the sleeve 12 to prevent friction with the sleeve 12 when the shaft 20 rotates, and the bearing gap is filled with lubricating fluid.

The upper portion of the shaft 20 is coupled to the hub 24 on which the disk is seated. The magnets 26 corresponding to the stator coils 14 are provided at both lower portions of the hub 24. The stator coil 14 and the magnet 26 generate electromagnetic torque by interaction with each other to rotate the shaft 20.

On the other hand, a thrust 40 is provided below the shaft 20 so as to support the shaft 20 in the axial direction. Here, a bearing gap is formed between the thrust 40, the sleeve 12, and the thrust pad 43, and the bearing gap is filled with a lubricating fluid. Rotating portions of the spindle motor such as the upper and lower journal bearings 21 and 22 formed in the upper and lower portions of the shaft 20 are radially supported, and the upper and lower thrust bearings 41 and 42 formed under the sleeve 12. Is supported in the axial direction.

  FIG. 2 is composed of a stator core 53 and a coil 54 connecting between the teeth 52 and the teeth forming a path of magnetic flux by contacting the permanent magnet 51 in a three-dimensional view of the inner rotor type motor.

 Among motors having a stator-coil structure, brushless DC motors, for example, perform according to the total flux density through which the magnetic flux generated from the current flowing through the permanent magnet 51 and the coil 54 flows through the stator and the rotor through the air gap. This is determined. That is, when the amount of magnetic flux generated from the coil 54 increases and the magnetic flux density increases, high torque is generated, and the efficiency is determined according to the current flowing through the coil 54.

However, the magnetic flux density with respect to the magnetic field strength formed in the stator varies with the material properties of the stator. As long as magnetic saturation does not occur, designing to increase the magnetic field strength by increasing the amount of magnetic flux generated from the coil 54 can ensure high efficiency. Therefore, designing by increasing the number of teeth 52 increases the number of windings of the equivalent coil 54 increases the torque constant and efficiency of the motor.

And, when manufactured by the conventional method, there is a problem that the opening of the slot narrows as the number of teeth 52 increases. The opening of the slot has physical limitations depending on the performance of the winding machine winding the coil 54 on the tooth 52. Therefore, there is a limit in increasing the number of slots, and recently, in a spindle motor using a hydrodynamic bearing, there is a problem that it is difficult to overcome the friction loss that increases with the increase of the speed and the decrease of the gap.

The present invention has been proposed to solve the above problems, it is possible to efficiently perform the winding operation even for teeth having a slot opening is difficult to winding, thereby increasing the torque constant without changing the size of the motor efficiency of the motor It is to provide a stator and a stator manufacturing method that can increase the.

According to an aspect of the present invention, a cut is formed in the direction of the center of the stator core so that the cutting surface is in contact with the stator core, a plurality of teeth extending inwardly of the stator core and the stator core between adjacent teeth. A stator is provided.

Here, the cut may include a first cut formed inside the stator core and a second cut formed outside the stator core, and the first cut may be formed at both adjacent sides of the first cut in the circumferential direction of the stator core. Can be.

In addition, according to another aspect of the present invention, a method for manufacturing a stator by winding a coil in a plurality of teeth extending inwardly of the stator core, the external force is applied to the stator core so that the slots on both sides adjacent to the teeth is expanded There is provided a stator manufacturing method comprising the steps of: winding a coil on the tooth and removing external force so that the slot is restored.

Here, the external force may be applied to both sides of the stator core in the direction of the center of the stator core.

As described above, according to the present invention, the coil winding can be efficiently performed, and the number of teeth can be increased, so that the magnetic flux density of the air gap can be increased, thereby increasing the torque constant of the electric motor.

The features and advantages of the present invention will become apparent from the following drawings and detailed description of the invention.

Hereinafter, embodiments of a stator according to the present invention and a method for manufacturing the same will be described in detail with reference to the accompanying drawings. In the following description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals, and Duplicate explanations will be omitted.

3 is a plan view showing a stator according to an embodiment of the present invention, Figure 4 is a perspective view showing a motor according to an embodiment of the present invention. 3 to 4, the stator 300, the stator core 302, the teeth 304, the first cut 306, the second cut 308, the slot 310, the coil 400, and the magnet 402, back yoke 404 is shown.

Stator according to an embodiment of the present invention, the cut is formed in the center direction of the stator core so that the cutting surface is in contact with the stator core, a plurality of teeth extending inwardly of the stator core and the stator core between adjacent teeth ( By including a cut, the coil winding can be efficiently performed and the number of teeth can be increased, so that the magnetic flux density between the magnet and the stator increases, thereby increasing the torque constant of the motor.

As shown in FIG. 3, the stator 300 may include a stator core 302 constituting an annular body and a plurality of teeth 304 extending inwardly of the stator core 302. Slots 310 are formed between the teeth 304.

The cut is formed so that the cut surface abuts on the stator core 302 between adjacent teeth 304 in the center direction of the stator core 302. In the cut winding the coil 400 to the stator 300, by applying an external force to the stator 300, the cut expands the slot 310 to wind the teeth 304, or lifts the teeth 304 to lift the windings. In the case of implementation, it is formed to facilitate its deformation. On the other hand, the stator 300 may have an elastic enough to be wound in the manner described above.

The stator 300 may be formed by stacking iron plates having the same cross section, and each iron plate may be formed using a press working or the like.

By forming a cut in the stator core 302, the coil 400 can be wound more easily on the tooth 304, and the number of teeth 304 of the stator 300 can be increased. An increase in the number of teeth 304 is associated with an increase in torque and efficiency of the motor. In particular, when the present invention is applied to a small spindle motor with spatial constraints, the winding density of the coil 400 may be improved.

As shown in FIG. 4, a magnet 402 and a back yoke 404 are formed inside the stator 300. Winding work is completed, the stator 300 is assembled to form a gap with the rotor and the magnet 402 and the back yoke 404 is generated in accordance with the current applied to the coil 400 to generate a rotational torque.

The torque constants of the conventional spindle motor for hard disk drive and the spindle motor for hard disk drive according to the present embodiment were compared by the finite element method, and the following results were obtained. The spindle motor according to the present embodiment has a structure of 12 poles 18 slots 310, and the existing spindle motor has a structure of 12 poles 9 slots 310, when winding the same number of coils 400 on each tooth 304, The torque constant of the existing spindle motor is 2.286mNm, the torque constant of the spindle motor according to this embodiment is 4.618mNm. It is shown that the torque constant of the spindle motor according to the present embodiment is improved compared to the torque constant of the spindle motor using the existing stator 300.

The cut may be formed on the inside or outside of the stator core 302. The first cut 306 may be formed inside the stator core 302, and the second cut 308 may be formed outside the stator core 302. In addition, the first cut 306 may be formed on both sides of the second cut 308 adjacent in the circumferential direction of the stator core 302. On the other hand, the direction in which the cut is formed, or the number thereof may be implemented in other forms in which deformation of the stator core 302 may be easily performed.

The cut surface of a cut is in contact. Thereby, the fall of the efficiency by self saturation by the formation of a cut can be prevented. In the case of the small spindle motor, the size of the stator 300 is not large and magnetic saturation may occur due to the formation of the cut. However, by forming the cut surfaces to be in contact with each other, the reluctance of the magnetic flux path on the cut surface of the cut can be prevented from increasing. This can prevent the deterioration of efficiency.

5 is a flowchart illustrating a method of manufacturing the stator 300 according to another embodiment of the present invention, and FIGS. 6 to 8 are plan views illustrating the stator 300 according to another embodiment of the present invention.

The stator 300 manufacturing method according to the present embodiment is a method of manufacturing the stator 300 by winding the coil 400 to a plurality of teeth 304 extending inside the stator core 302. Exerting an external force on the stator core 302 so that the slots 310 on both sides thereof are extended, winding the coil 400 on the tooth 304, and removing the external force so that the slot 310 is restored. Including the step of winding the coil 400 can be efficiently performed, the number of teeth 304 can be increased, the magnetic flux density between the magnet 402 and the stator 300 is increased to increase the torque constant of the motor You can increase it.

The method of manufacturing the stator 300 according to the present embodiment will be described by using an example performed using the stator 300 according to the embodiment of the present invention described above. Therefore, the structure of the stator 300 of this embodiment is the same as that of the stator 300 mentioned above.

First, as shown in FIG. 6, an external force is applied to one side of the stator core 302 toward the center of the stator core 302 so that the slots 310 on both sides adjacent to the tooth 304 are expanded. (S100) An external force is applied to the outer circumference of the stator core 302 where the teeth 304 to be implemented are to be wound. At this time, while the cut formed around the tooth 304 to implement the winding is deformed, the slot 310 on both sides of the tooth 304 to implement the winding is expanded to secure a space for performing the winding.

Next, winding is performed on the teeth 304 having spaces at both sides. As illustrated in FIG. 7, the slot 310 is enlarged on both sides of the tooth 304 to allow winding to be performed more easily, and the stator 300 having a plurality of teeth 304 formed therein may also be wound. Could be applied. In addition, spaces may be provided at both sides of the teeth 304 to perform winding, thereby increasing the number of windings of the coil 400, thereby improving winding density.

Next, the external force is removed to recover the slot 310. When the external force is removed, the cut deformed in the above-described step is returned to the original shape, and the stator 300 as a whole is returned to the original shape. The stator 300 may be a material having elasticity within the amount of deformation generated in the step of applying an external force. When the external force is removed, the stator 300 returns to its original shape.

On the other hand, if the external force is applied to both sides of the outer periphery of the stator 300 in the direction of the center of the stator core 302, the slots 310 on both sides of the tooth 304 at positions symmetrical to both sides of the stator 300 In an enlarged manner, the winding of the coil 400 described above will be able to simultaneously winding the two teeth 304.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention as set forth in the claims below It will be appreciated that modifications and variations can be made.

1 is a cross-sectional view showing a spindle motor.

Figure 2 is a perspective view of the inner rotor type motor according to the prior art.

3 is a plan view showing a stator according to an embodiment of the present invention.

4 is a perspective view of a motor according to an embodiment of the present invention.

5 is a flow chart showing a stator manufacturing method according to another embodiment of the present invention.

6 to 8 is a plan view showing a stator according to another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

300: stator 302: stator core

304: Teeth 306: First Cut

308: second cut 310: slot

400: coil 402: magnet

404: Back York

Claims (5)

A stator core; A plurality of teeth extending inwardly of the stator core; And And a first cut and a second cut respectively formed in the center direction of the stator core such that a cutting surface abuts inside and outside the stator core between adjacent teeth. delete The method of claim 1, The first cut is A stator formed on opposite sides of the second cut in the circumferential direction of the stator core. A method of manufacturing a stator by winding a coil around a plurality of teeth extending inwardly of the stator core, Applying an external force to the stator core such that slots on both sides adjacent to the tooth are expanded; Winding a coil on the tooth; And Removing the external force so that the slot is restored. The method of claim 4, wherein The step of applying the external force Stator manufacturing method characterized in that the external force is applied to both sides of the stator core in the direction of the center of the stator core.

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