CN1213048A - Method for fabricating electromagnet control bearing and brushless DC motor using the same - Google Patents

Abstract

The invention is provided with an electromagnetic generating device, which can make the gap between the shaft and the bearing eccentric to the desired direction when the speed exceeds a certain level. It includes the steps of preparing a jig with the same inner diameter as the outer diameter of the bearing and having an inlet on at least one side, disposing the internal electromagnetic force generating device of the jig on the shaft through the jig inlet, and installing the bearing part through the jig inlet. The step of installing inside each electromagnetic force generating device, the step of injecting resin between the jig and the bearing through the inlet of the jig, the step of hardening the resin between the jig and the bearing, and the step of fixing the electromagnetic force generating device and the bearing to each other, In the step of maintaining a space for fluid flow, the electromagnetic force generating device and the bearing part are separated from the jig.

Description

Manufacturing method of electromagnetic control bearing and brushless DC motor using the same

The present invention relates to a manufacturing method of an electromagnetic control bearing and a brushless DC motor using it, and more specifically relates to an electromagnetic force generating device for fixing an electromagnet on the circumferential surface of the bearing through a thermosetting resin. The interval is eccentric to the required direction at a certain speed, so when the shaft rotates at high speed, the vortex phenomenon of the oil can be reduced, and the manufacturing method of the electromagnetic control bearing and the brushless using it can improve the characteristics of low vibration and low noise DC.

Generally, in a hydrodynamic bearing used in a spindle motor, oil for generating dynamic pressure is filled between the shaft and a bearing rotatably supported therewith. 1 is a sectional view of a conventional spindle motor. A bearing 1a is fitted in the upper center of a base 1, and a shaft 2 is provided rotatably inside the bearing 1a. Furthermore, a stator 1b constituting a stator is provided on the upper outer periphery of the base 1, and a rotor 3 in the form of a cover is provided on the upper end of the shaft 2. As shown in FIG. There is a magnet 3a surrounding the stator 1b on the inner periphery of the rotor 3. When power is applied to the coil 1c wound on the stator 1b, the magnet 3a generates a magnetic force and the rotor 3 rotates around the shaft 2.

In the conventional spindle motor having such a structure, when the shaft 2 rotates at a high speed, pressure is generated by the oil filled between the bearings 1a. Therefore, the shaft 2 is rotatably supported in the direction of the radius of rotation, and while the shaft 2 is rotating, the rotating disk placed on the upper part of the rotor 3 rotates while reproducing the situation of the rotating disk.

However, in the case of a hydrodynamic bearing, oil whirls and instability occur at low speeds. The oil vortex phenomenon, the bearing eccentricity between the bearing 1a and the shaft 2 begins to decrease above a certain speed. This is because the Sommerfeld constant (sommerfeidnumber) decreases with the increase of speed, and the eccentricity mantle decreases. Such a phenomenon causes the oil rotating on the outer peripheral surface with the rotation of the shaft 2 to produce a certain velocity distribution, and generally occurs on a positive circular hydrodynamic bearing without a dynamic pressure generating groove on the outer peripheral surface of the shaft 2. Therefore, its disadvantage is that the characteristics of low vibration and low noise at high speed are very low.

In view of various problems existing in the past, the present invention installs an electromagnetic force generating device using an electromagnet on the outer circumference of the bearing, so that when the distance between the shaft and the bearing is above a certain speed, the required eccentricity is generated and the oil pressure is increased. The occurrence rate, the manufacturing method of the electromagnetically controlled bearing which improves the dynamic characteristics at high speed and the brushless DC motor using it.

In order to achieve the above object, in the manufacturing method of the electromagnetic control bearing of the present invention, in order to generate a certain dynamic pressure in the fluid between the shaft and the inner diameter of the bearing, there is an electromagnetic control bearing with more than one electromagnetic generating device acting on the shaft on the shaft. Among them, the following steps are included: the step of preparing a jig with the same inner diameter as the outer diameter of the target bearing and having an inlet on at least one side and disposing the internal electromagnetic force generating device of the jig through the inlet of the jig The steps of placing the above-mentioned electromagnetic force generators on the shaft through the inlet of the jig, and the step of injecting resin between the jig and the bearing through the inlet of the jig, and using The step of hardening the resin between the jig and the bearing so that the electromagnetic force generator and the bearing are fixed to each other and the step of processing the inner diameter of the bearing to maintain a space for fluid flow between the shaft and the step are combined with each other. The electromagnetic force generating device and the bearing part are separated from the above-mentioned frame, and the step of electromagnetically controlling the bearing is completed.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a sectional view of a conventional motor bearing.

Fig. 2 is a sectional view of the motor of the present invention.

Fig. 3 is an isolated oblique view of the electromagnetic control bearing of the present invention.

4 and 5 show cross-sectional views of the manufacturing process of the electromagnetically controlled bearing of the present invention.

Fig. 6 shows a flowchart of the manufacturing process of the electromagnetically controlled bearing of the present invention.

Fig. 7 shows a sectional view of an electromagnetic control bearing according to another embodiment of the present invention.

Symbol Description

11 electromagnetic control bearing

11a bearing part

12 axis

13 oil

14 stator

15 coils

16 sockets

17 rotors

18 magnets

19 electromagnetic generator

20 electromagnet

21 Electromagnetic Force Generation Department

22 coils

23 induction coil

24 controllers

25 amps

30 frame

30a reinforced frame

31 thermosetting resin

The electromagnetic control bearing 11 has the following configuration. Maintain the fluid space where the shaft can rotate inside, the inner wall supported around the shaft 12 and the outer wall that can fix the bearing 11 around the inner wall and the upper and lower end walls connecting the inner wall and the outer wall and between the inner wall and the outer wall, for the above-mentioned The fluid between the shaft 12 and the inner wall generates a certain dynamic pressure, and more than one electromagnetic force generating device 19 with gravitational force is arranged in the direction of the rotation radius of the shaft 12 and the fixed electromagnetic force generating device 19 is filled between the above-mentioned inner wall and the outer wall. Made of thermosetting resin 31. Therefore, the inner wall is composed of the bearing 11a having a fluid flow space between the inner diameter and the processed shaft, and the outer wall uses a reinforcing frame 30 that prevents deformation when the thermosetting resin 31 expands during hardening. In addition, it is preferable to use a polymer coating (polycoat) as a thermosetting resin.

The electromagnetic generator 19 is a device that can suppress the oil vortex phenomenon that occurs when the shaft 12 rotates above a certain speed, so that the shaft 12 can be attracted to a desired direction to increase the eccentricity. The electromagnetic generator 19 is provided with a plurality of electromagnets 20 radially on the outer peripheral surface of the bearing portion 11a. These electromagnets are rectangular, and each electromagnet 20 has a pair of electromagnetic generating parts 21 on both sides facing the front of the shaft 12 . Furthermore, coils 22 are wound around each electromagnetic generator 21, and power is applied to these coils according to the rotational speed of the shaft.

During the high-speed rotation of the shaft 12, when the eccentricity decreases, power is selectively applied to each coil 22, and at the same time, the shaft 12 is attracted to the electromagnet 20 after the electromagnetic force is generated by the electromagnetic generator 21. Also, each electromagnetic force generating portion 21 has an induction coil 23 that generates an induced current. The induction coil 23 generates an induced current according to the distance difference between the shaft 12 and the electromagnet 20 , and supplies power to the coil 22 according to the variation of the induced current. Such induced current is amplified by the amplifier 25 and then input to the controller 24. The controller 24 applies power to the electromagnet 20 according to the distance difference between the electromagnet 20 and the shaft 12. In more detail, power is applied to the coil 22 of the electromagnet 20 according to the control signal from the controller 24, and the electromagnetic force generated by the electromagnetic force generator 21 is used to attract the shaft 12 to a desired direction. For example, during the rotation of the shaft 12, it can be attracted to any one direction and rotate in an eccentric state. Moreover, the shaft 12 can be continuously in an eccentric state on each magnet 20 , that is, a state of idling in a vortex inside the bearing 11 , so that the compressibility of the oil 13 can be increased.

The motor with the electromagnetically controlled bearing of the present invention has the following configurations.

The bearing part 11a constituting the bearing 11 and the reinforced frame 30 containing the electromagnet 20 are inserted into the motor base 10 and assembled. Methods of assembling the reinforcement frame 30 inside the base 10 include a fitting method and an assembly method of inserting the reinforcement frame 30 into the base 10 and simultaneously fastening the outer periphery with screws. In addition, a stator 14 around which a coil 15 is wound is provided on the outer periphery of the base 10 . Further, a rotatable shaft 12 is inserted into the bearing 11 , and oil 13 capable of generating dynamic pressure is filled between the shaft 12 and the bearing 11 .

In addition, a hub 16 is fitted to the upper end of the shaft 12, and a rotor 17 is provided on the outer periphery thereof so as to be rotatable together. The rotor 17 is coaxial with the stator 14 and is rotatably supported on the shaft 12 by a cylinder-shaped wall surrounding the stator and a magnet 18 attached to the inside of the cylinder-shaped wall with a gap between the stator 14 and the stator 14. The upper shaft sleeve 16 constitutes. Therefore, when a voltage is applied to the coil 15, the magnet 18 generates a magnetic force, and the rotor 17 rotates together with the shaft 12 at a high speed.

In the present invention thus constituted, the bearing 11 has an electromagnetic force generator capable of forcing the shaft 12 to be eccentric in a desired direction. The electromagnetic force generating device 19, when the shaft 12 is rotating at a high speed, the eccentricity decreases, so that the dynamic pressure of the oil 13 does not decrease, so the oil vortex phenomenon can be suppressed. Such an electromagnetic generator 19 is constituted by having a plurality of electromagnets 20 radially inside the bearing 11 . Each electromagnet 20 has a pair of electromagnetic force generators 21 facing the front of the shaft 12 . When a voltage is applied to the coils 22 wound around the electromagnetic force generator 21, an electromagnetic force is generated. And on each electromagnetic force generation part 21, be equipped with the induction coil 23 that produces induction current, when shaft 12 and each magnet 20 produce distance difference, induction coil 23 then produces induction current, and induction current is sent to controller 24 by amplifier 25 , to adjust the electromagnetic force according to the amount of induced current.

The control process of the shaft 12 will be described below. When the shaft 12 rotates at a high speed, the eccentricity decreases. At this time, a plurality of induction coils 23 are provided on the electromagnet 20 , and induced currents are generated due to the distance difference from the shaft 23 or the rotation speed, and these are amplified by the amplifier 25 and then output to the controller 24 . Then, the controller 24 sends the power signal that should be applied to the coil 22 that generates the distance difference to the computer. Therefore, power is applied to the coil 22, and the shaft 12 is attracted to a desired direction after the electromagnetic force is generated by the electromagnetic force generator 21. Therefore, after the shaft 12 is forced to eccentric to the bearing 11, the dynamic pressure of the oil 13 is increased, and the vortex phenomenon of the oil is reduced, which can improve the dynamic characteristics of high-speed rotation. In addition, the power supply added to each electromagnet 20 can make the shaft 12 continuously eccentric, rotate to the state of vortex, and increase the pressure of the oil.

The method of manufacturing the hydrodynamic bearing device of the present invention is as follows.

Fig. 3 is the separation oblique view of the bearing of the present invention, Fig. 4 and Fig. 5 are the cross-sectional views showing the manufacturing process of the bearing of the present invention, Fig. 6 is the manufacturing process flow chart showing the bearing of the present invention, prepare a bearing with purpose and 11 outside Through the step (S100) of the jig 30 having the inlet on at least one side of the same inner diameter and having an inlet on at least one side of the inside of the jig 30, there will be at least one of the same outer diameters as the outer diameter of the bearing. The step of arranging the bearing reinforcement jig 30a in the jig 30 (S110) and the step of arranging the above-mentioned electromagnetic force generators 19 inside the reinforcement jig 30a on the same bearing through the entrance of the jig 30 (S120) And, a step of installing the bearing portion 11a inside each electromagnetic force generating device 19 through the entrance of the jig 30 (S130).

Here, the jig 30 has an octagonal tubular shape, and the electromagnetic force generators 19 are disposed on respective inner sides corresponding to each other. During the process, the electromagnetic force generating devices 19 face each other. Furthermore, the front end surfaces of the electromagnetic force generating parts 21 of these electromagnetic force generating devices 19 are formed in an arc shape in contact with the outer peripheral surface of the bearing 11a.

Next, after the step of injecting resin between the reinforced frame 30a and the above-mentioned bearing portion 11a through the inlet of the frame 30 (S140) and hardening the resin between the reinforced frame 30a and the above-mentioned bearing portion 11a, the reinforced frame 30a, the electromagnetic force The step of fixing the generating device 19 and the bearing part 11a (S150) and the step of processing the inner diameter of the above-mentioned bearing part 11a so as to maintain a space for fluid flow with the above-mentioned shaft 12 (S160) and will have the reinforced frame 30a and the electromagnetic The bearing part 11a of the force generating device 19 is separated from the above-mentioned jig 30, and the step of electromagnetically controlling the bearing is completed (S170).

FIG. 7 is a sectional view of a bearing device in another embodiment of the present invention, and the jig 32 is a cylindrical structure. When the jig 32 has a cylindrical structure, when combined with the inner peripheral surface constituting the motor base 10, since the motor base 10 is circular, the assembly performance can be improved. In the bearing device of other embodiments of the present invention, a plurality of guide grooves 33 are formed on four sides of the inner peripheral surface of a cylindrical frame 32 . These guide grooves 33 are in a state corresponding to one side surface of the electromagnet 20 . Therefore, when the electromagnets 20 are coupled to these guide grooves, they are fixed in a non-movable state, and after inserting the bearings 11a between the electromagnets 20, the thermosetting resin 31 is filled between the bearings 11a and the frame 32. After filling the thermosetting resin 31, the bearings 11a and the electromagnets 20 are fixed in a non-movable state inside the jig 32, and then the inner peripheral surface of the bearing part 11a is precisely machined, and the shaft 12 is rotatably inserted to complete the process. Bearing devices of other embodiments of the present invention.

As described above, according to the present invention, when a plurality of electromagnets and bearing parts are arranged inside the jig on the joint base and fixed with thermosetting resin, the bearing of the present invention is completed. When such a bearing is fixed inside the base, a rotatable structure is formed to support the shaft on the inner peripheral surface of the bearing, and the shaft can be rotatably supported when dynamic pressure is generated during the rotation of the shaft. Moreover, when the amount of eccentricity decreases during the rotation of the shaft, power is applied to the coils of each electromagnetic force generating device to attract the shaft to a desired direction and increase the amount of eccentricity. Therefore, after increasing the dynamic pressure, the characteristics of low noise and low vibration during high-speed rotation can be improved, and a simple bearing structure can achieve good results.

Claims (14)

1. In order to generate a certain dynamic pressure in the fluid between the shaft and the inner diameter of the bearing, the manufacturing method of the electromagnetically controlled bearing having more than one electromagnetic force generating device acting on the shaft is characterized in that it comprises the following steps, 1) A step of preparing a jig having the same inner diameter as the intended bearing outer diameter and having an inlet on at least one side, 2) a step of arranging an electromagnetic force generating device coaxially inside the jig through the entrance of the jig, 3) a step of disposing the bearing part inside each of the above-mentioned electromagnetic force generating devices through the entrance of the above-mentioned jig, 4) The step of injecting resin between the above-mentioned jig and the above-mentioned bearing through the inlet of the above-mentioned jig, 5) A step of hardening the resin between the jig and the bearing so that the electromagnetic force generator and the bearing are fixed to each other, 6) The step of processing the inner diameter of the above-mentioned bearing part so as to maintain a space for fluid flow between the above-mentioned shaft, 7) Separate the combined electromagnetic force generating device and the bearing part from the above-mentioned jig to complete the step of electromagnetically controlling the bearing. 2. 1. The method of manufacturing an electromagnetic control bearing according to claim 1, wherein in order to strengthen the bonding force of the resin, a bearing portion having a concave-convex outer circumference is provided inside the electromagnetic force generator. 3. In order to generate a certain dynamic pressure in the fluid between the shaft and the inner diameter of the bearing, the manufacturing method of the electromagnetically controlled bearing having more than one electromagnetic force generating device acting on the shaft is characterized by comprising the following steps, 1) A step of preparing a jig with the same inner diameter as the outer diameter of the intended bearing and having inlets on at least one side, 2) The step of arranging at least one bearing reinforcing jig having an inlet at least one side and having the same outer diameter as the bearing outer diameter inside the jig, 3) the step of coaxially arranging each electromagnetic force generating device inside the above-mentioned reinforced frame through the entrance of the above-mentioned frame, 4) Install the bearing part inside each of the above-mentioned electromagnetic force generators through the entrance of the jig, 5) The step of injecting resin between the above-mentioned reinforcement frame and the above-mentioned bearing through the inlet of the above-mentioned frame, 6) A step of hardening the resin between the reinforcing frame and the bearing so that the reinforcing frame, the electromagnetic force generating device, and the bearing are fixed to each other, 7) The step of processing the inner diameter of the above-mentioned bearing part so as to maintain a space for fluid flow between the above-mentioned shaft, 8) Separate the reinforced frame, the electromagnetic force generating device and the bearing part from the frame to complete the step of electromagnetically controlling the bearing. 4. The manufacturing method of the electromagnetic control bearing according to claim 3, characterized in that in order to strengthen the bonding force of the above-mentioned resin, a bearing part with concave and convex on the outer peripheral surface and a reinforcing frame with concave and convex on the inner peripheral surface are provided inside the frame . 5. A brushless direct current motor characterized by having the following constitution, A stator wound with coils; Fix the above-mentioned stator on the base frame of the upper part; the shaft serving as the axis of rotation of the aforementioned motor; The magnet is rotatably supported on the shaft by a cylinder-shaped wall located on the same axis as the stator and surrounding the stator and attached to the inside of the cylinder-shaped wall with a certain gap between the stator and the stator. The rotor formed by the upper sleeve; A fluid flow space for the shaft to be rotatably held inside, an inner wall surrounding the shaft support and an outer wall surrounding the inner wall to which the bearing system can be fixed and the upper and lower wall ends connecting the inner wall and the outer wall and located on the inner wall and Between the outer walls, the fluid between the above-mentioned shaft and the inner wall generates a certain dynamic pressure, and there is more than one electromagnetic force generating device acting on the gravitational force in the direction of the rotation radius of the above-mentioned shaft, and the fixed electromagnetic force generating device is filled between the above-mentioned inner wall and the outer wall Made of thermosetting resin, the upper part of the base that rotates coaxially with the shaft and the stator is set to penetrate the bearing system and the electromagnetic force is generated when the dynamic pressure decreases during the high-speed rotation of the shaft. After supplying current to the device, it is composed of a controller that controls the above-mentioned axis of suction. 6. 5. The brushless DC motor according to claim 5, wherein said electromagnetic generating means is composed of an electromagnetic force generating part and a coil wound around said electromagnetic generating part. 7. 5. The brushless DC motor according to claim 5, wherein the electromagnetic generating means changes in the size of the fluid flow space formed between the electromagnetic force generating part and the fluid flowing between the shaft and the inner wall of the bearing wound around the electromagnetic generating part. At this time, the induction coil that generates the induction current is connected to the induction coil to amplify the induction current, and the amplified induction current is used to control the amplifier of the above-mentioned controller and wound on the above-mentioned electromagnetic force generating part to generate electromagnetic force according to the control signal of the above-mentioned controller. The force is formed by guiding the above-mentioned shaft to the coil on one side. 8. 5. The brushless DC motor according to claim 5, wherein the inner wall of the bearing is formed of a bearing having a fluid flow space between the shaft and the shaft, and the inner wall of the bearing is made of the thermosetting resin, which can suppress Constructed due to the expansion of the deformed reinforcement frame. 9. 5. The brushless DC motor according to claim 5, wherein said electromagnetic generating device is composed of two or more centered on said axis and maintained at a certain angle in the radial direction. 10. 9. The brushless DC motor according to claim 9, wherein said electromagnetic generating means is composed of an electromagnetic force generating part and a coil wound around said electromagnetic generating part. 11. The brushless DC motor according to claim 9, wherein the electromagnetic generating means is changed in size by the electromagnetic force generating part and the fluid flow space formed between the shaft and the inner wall of the bearing around which the electromagnetic generating part is wound. At this time, the induction coil that generates the induction current is connected to the induction coil to amplify the induction current, and the amplified induction current is used to control the amplifier of the above-mentioned controller and wound on the above-mentioned electromagnetic force generating part to generate electromagnetic force according to the control signal of the above-mentioned controller. The force is formed by guiding the above-mentioned shaft to the coil on one side. 12. The brushless DC motor according to claim 5, wherein said electromagnetic generator has more than two in the radial direction. 13. 12. The brushless DC motor according to claim 12, wherein said electromagnetic generating means is constituted by an electromagnetic force generating part and a coil wound around said electromagnetic generating part. 14. 12. The brushless DC motor according to claim 12, wherein the electromagnetic generating means changes in the size of the fluid flow space formed between the electromagnetic force generating part and the fluid flowing between the shaft and the inner wall of the bearing wound around the electromagnetic generating part. At this time, the induction coil that generates the induction current is connected to the induction coil to amplify the induction current, and the amplified induction current is used to control the amplifier of the above-mentioned controller and wound on the above-mentioned electromagnetic force generating part to generate electromagnetic force according to the control signal of the above-mentioned controller. The force is formed by guiding the above-mentioned shaft to the coil on one side.

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