KR20040009157A - Motor having thrust magnetic bearing - Google Patents

Abstract

PURPOSE: A thrust magnetic bearing motor is provided to achieve improved stability of operation and lengthen the lifespan of the motor, while reducing noises and costs. CONSTITUTION: A thrust magnetic bearing motor comprises a fixed shaft(1) having a herring bone-shaped groove(2) formed therein; a rotor(20) arranged around the fixed shaft in such a manner that the rotor corresponds to the stator in a vertical direction, wherein the rotor is equipped with a rotating permanent magnet(22); and a thrust magnetic bearing(40) interposed between the fixed shaft and the rotor, and which supports an axial load. The thrust magnetic bearing is formed into a pair magnetized in the radial direction of the fixed shaft and mounted on the fixed shaft and the rotor, respectively.

Description

Thrust Magnetic Bearing Motors {MOTOR HAVING THRUST MAGNETIC BEARING}

The present invention relates to a fluid dynamic DVC compact motor, and more particularly to a thrust magnetic bearing motor capable of realizing a stable motor operating structure by using two pairs of radially magnetized thrust magnetic bearings.

1 is a cross-sectional view showing an example of a thrust magnetic bearing motor of the prior art.

The thrust magnetic bearing motor of the related art has a fixed shaft 50 having a herringbone groove 51 formed at two upper and lower portions as shown in FIG. 1, and a PCB 63 fixed at a lower side of the fixed shaft 50. Stator 60 which is a lower drum provided with yoke 62 and an upper drum which is positioned around the fixed shaft 50 so as to correspond to the stator 60 up and down and is provided with a rotating permanent magnet 72. The rotor 70 is comprised.

Here, a cover 80 fixed to an upper side of the fixed shaft 50 is positioned above the rotor 70, and a transformer for extending a drum signal between the cover 80 and the rotor 70. 85 is located.

In particular, in the space between the stator 60 and the rotor 70, a thrust magnetic bearing 90 is provided between the fixed shaft 50 and the rotor 70 so as to support the axial load of the rotor 70. Is installed.

As shown in FIG. 2, the pair of thrust magnetic bearings 90 includes a fixed side magnet 91 installed on the fixed shaft 50, and a rotating side magnet 95 installed below the rotor 70. Each magnet 91, 95 is magnetized so that opposite surfaces have opposite polarities.

Referring to the operation of the thrust magnetic bearing motor as described above, when a current is applied to the PCB 63 of the stator 60, the rotor 70 by forming a magnetic field with the rotating permanent magnet 72 of the rotor 70 ) And the rotating permanent magnet 72 is rotated about the fixed shaft (50).

At this time, the dynamic pressure is generated between the rotor 70 and the herringbone groove 51 of the fixed shaft 50, so that the rotor 70 can rotate smoothly.

In particular, the thrust magnetic bearings 90 are disposed so that the same polarity is opposed to each other, the positions of the thrust magnetic bearings are attracted to each other.

However, in the thrust magnetic bearing motor of the prior art as described above, since the magnetizing direction of the thrust magnetic bearing 90 is axial as shown in FIG. 3, the force that the actual thrust bearing can support is not large. Therefore, thrust than the force applied to the actual rotor 70, that is, the force applied between the rotating permanent magnet 72 and the yoke 62 located behind the PCB 63 to the weight of the rotor 70 is thrust. When the axial bearing force of the magnetic bearing 90 becomes small, a problem arises in that the excess downward force acts as a load when the motor rotates, so that the motor cannot operate stably.

The present invention has been made to solve the above problems, by providing two pairs of thrust magnetic bearings magnetized in the radial direction to provide a thrust magnetic bearing motor to maintain a stable axial support force to improve the reliability of motor operation The purpose is to.

In addition, another object of the present invention is to provide a thrust magnetic bearing motor in which a yoke made of ferromagnetic material is installed around a rotating permanent magnet, thereby increasing the supporting force for fixing the axial position, thereby enabling more stable motor operation.

1 is a cross-sectional view of a conventional thrust magnetic bearing motor.

FIG. 2 is a partial detail “A” of FIG. 1; FIG.

3 is a diagram showing magnetization directions and magnetic force lines of a magnet in a conventional thrust magnetic bearing motor;

4 is a cross-sectional view of a thrust magnetic bearing motor according to the present invention.

FIG. 5 is a partial detail of “B” in FIG. 4; FIG.

Figure 6 is a view showing the magnetization direction and the magnetic force line of the magnet in the thrust magnetic bearing motor according to the present invention.

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

1: fixed shaft 2: herringbone groove

10: Stator 13: PCB

15: York 20: rotor

22: rotating permanent magnet 40: thrust magnetic bearing

41A, 41B: Fixed side magnet 45A, 45B: Rotating side magnet

The thrust magnetic bearing motor according to the present invention for realizing the above object is a fixed shaft with a herringbone groove, a stator fixed to the lower side of the fixed shaft and provided with a yoke at the top, and corresponding to the stator up and down. A thrust magnetic bearing motor comprising a rotor positioned around a fixed shaft and provided with a rotating permanent magnet, and a thrust magnetic bearing provided between the fixed shaft and the rotor to support an axial load. Magnetized in the radial direction of the fixed shaft is characterized in that consisting of a plurality of pairs respectively installed on the fixed shaft and the rotor.

In addition, the thrust magnetic bearing motor according to the present invention for realizing the above object is a fixed shaft with a herringbone groove, a stator fixed to the lower side of the fixed shaft and provided with a yoke at the top, and up and down with the stator A thrust magnetic bearing motor comprising a rotor positioned around the fixed shaft and provided with a rotating permanent magnet, and a thrust magnetic bearing provided between the fixed shaft and the rotor to support an axial load, wherein the yoke is magnetic. It is made of a material is located around the rotating permanent magnet, characterized in that the thrust magnetic bearing action.

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

4 is a cross-sectional view of a thrust magnetic bearing motor according to the present invention, and FIG. 5 is a partial detail "B" of FIG. 6 is a diagram showing magnetization directions and magnetic force lines of a magnet in a thrust magnetic bearing motor according to the present invention.

The thrust magnetic bearing motor according to the present invention has a fixed shaft (1) having a herringbone groove (2) formed in two upper and lower portions, as shown in Figure 4, and fixed to the lower side of the fixed shaft (1) and the yoke and PCB on the top A stator 10 having a printed circuit board, a rotor 20 positioned around the fixed shaft 1 so as to correspond to the stator 10 up and down, and provided with a rotating permanent magnet 22; It is composed of a thrust magnetic bearing 40 provided between the fixed shaft 1 and the rotor 20 to support the axial load.

A cover 30 fixed to an upper side of the fixed shaft 1 is positioned above the rotor 20, and a transformer (TRANSFORMER) for extending a drum signal between the cover 30 and the rotor 20 ( 35) is located.

In particular, the thrust magnetic bearing 40 is magnetized in the radial direction of the fixed shaft (1) consists of a plurality of pairs respectively installed on the fixed shaft (1) and the rotor (20). In this embodiment, the thrust magnetic bearing 40 is preferably composed of two pairs.

That is, the two pairs of thrust magnetic bearings 40 have two fixed side magnets 41A and 41B installed on the fixed shaft 1 and rotations provided below the rotor 20, as shown in FIG. It consists of side magnets 45A and 45B, and each of the stationary and rotating magnets 41A and 41B and 45A and 45B is magnetized so that the opposing surfaces have opposite polarities to each other.

Here, since the size and position of the magnets 41A, 41B (45A, 45B) that can be used in general because the internal space of the DVC motor is narrow is very limited, it is shown in FIG. As shown, the magnets 41A, 41B, 45A, 45B use two pairs of four, each magnetizing in a different direction in the radial direction. Each of the fixed side magnets 41A and 41B and the rotating side magnets 45A and 45B is integrally formed by bonding a pair of up and down in the inverted direction to each other.

In such a structure, since the pole arrangement of the magnets 41A and 41B (45A and 45B) is not fundamentally different from the conventional method, the direction of the force acting between the fixed side and the rotating magnets 41A and 41B (45A and 45B) It is also the same as the conventional method.

That is, although the attraction force between the fixed and rotating magnets 41A and 41B (45A, 45B) acts in the radial direction, the gap is fixed mechanically so that the gap between the inner and outer magnets 41A, 41B (45A, 45B) The gaps are maintained at regular intervals, and in the vertical direction, they are aligned side by side based on the vertical magnetic center of the inner and outer magnets, that is, the contacts of the upper and lower magnets, and if they try to escape, the magnets 41A, 41B (45A, 45B). The workforce of the liver stops this.

For reference, as shown in FIG. 3, the magnets are magnetized in the vertical direction, and thus the path of the magnetic force lines that are the main magnetic fluxes is formed as long as in FIG. 3, so that the forces of the thrust magnets to be aligned side by side are relatively small, and thus the vertical equilibrium position is caused by other external forces. Is misaligned.

On the other hand, in the thrust magnetic bearing structure of the present invention, even if magnets of the same size are magnetized in the radial direction, as shown in FIG. 6, the magnetic force lines are much shorter, so that the forces between the magnets facing each other become much larger. The equilibrium position of the direction can be kept constant.

Next, the yoke 15 is made of a ferromagnetic material and is positioned around the rotating permanent magnet 22 and installed to serve as a thrust magnetic bearing. The yoke 15 is preferably positioned at a predetermined interval in the outer peripheral region of the rotary permanent magnet 22.

Accordingly, as the yoke 15 of the magnetic material is designed to be inserted around the rotating permanent magnet 22, mutual attraction force is acting between the rotating permanent magnet 22 and the yoke 15, which is an axial direction. Since it can be used as a supporting force for fixing the position, it is possible to secure a more stable support structure than the existing when rotating or stopping the motor.

The thrust magnetic bearing motor according to the present invention constructed and operated as described above constitutes two pairs of thrust magnetic bearings magnetized in a radial direction, and is combined with each other in two parts by installing a yoke around a rotating permanent magnet for greater verticality. There is an advantage that can secure the bearing capacity of the direction.

Therefore, in the case of the vertical magnetized magnet as in the prior art, the path of the magnetic flux is long, and thus the force is not sufficient. However, in the case of the magnet magnetized in the radial direction as in the present invention, the magnetic flux path is short, so that a larger force can be generated in the same space. The lack of internal space in DVC compact motors can compensate for the limited size of magnets available. In addition, the inserted magnetic yoke also increases the bearing capacity in the vertical direction, enabling a more stable motor system.

As a result, the thrust magnetic bearing motor according to the present invention can operate much more stably than the conventional hydrodynamic DVC compact motor, and provides effects such as improved impact resistance, increased service life, reduced noise and vibration, and cost reduction when the motor is operated. Done.

Claims (6)

A fixed shaft having a herringbone groove, a stator fixed to a lower side of the fixed shaft and having a yoke at an upper portion thereof, a rotor positioned around the fixed shaft so as to correspond to the stator up and down, and provided with a rotating permanent magnet; A thrust magnetic bearing motor comprising a thrust magnetic bearing provided between a fixed shaft and a rotor to support an axial load, The thrust magnetic bearing motor is magnetized in the radial direction of the fixed shaft, the thrust magnetic bearing motor, characterized in that composed of a plurality of pairs respectively installed on the fixed shaft and the rotor. The method of claim 1, The thrust magnetic bearing motor, characterized in that composed of two pairs of thrust magnetic bearings. The method according to claim 1 or 2, The yoke is made of a magnetic material and is positioned around the rotating permanent magnet, the thrust magnetic bearing motor, characterized in that the thrust magnetic bearing action. The method of claim 3, wherein The yoke is thrust magnetic bearing motor, characterized in that positioned at a predetermined interval in the outer peripheral region of the rotating permanent magnet. A fixed shaft having a herringbone groove, a stator fixed to a lower side of the fixed shaft and having a yoke at an upper portion thereof, a rotor positioned around the fixed shaft so as to correspond to the stator up and down, and provided with a rotating permanent magnet; A thrust magnetic bearing motor comprising a thrust magnetic bearing provided between a fixed shaft and a rotor to support an axial load, The yoke is made of a magnetic material and is positioned around the rotating permanent magnet, the thrust magnetic bearing motor, characterized in that the thrust magnetic bearing action. The method of claim 5, wherein The yoke is thrust magnetic bearing motor, characterized in that positioned at a predetermined interval in the outer peripheral region of the rotating permanent magnet.