CN102072249A - Large-bearing-capacity radial magnetic bearing - Google Patents

Abstract

Large bearing capacity radial magnetic bearing, composed of permanent magnet, control side stator magnetic ring, control side stator core, excitation coil, control side rotor core, load side stator magnetic ring, load side stator core big end, load side stator core The small end, the load-bearing side rotor core, and the rotor magnetic ring are composed. The stator core is divided into left and right ends, which are the control side and the load-bearing side respectively. The stator core on the control side includes four stator poles in the positive and negative directions of X and Y, which are connected by a yoke, and each stator pole is wound with an excitation coil, and the stator core on the load-bearing side includes a magnetic pole with a larger area in the direction of gravity and a smaller magnetic pole. The permanent magnets are placed between the stator magnetic rings on both sides to provide a bias magnetic field for the control side and a permanent magnetic field for the load-bearing side to generate unilateral magnetic pull. The invention solves the disadvantages of large volume and large levitation current when the existing radial magnetic bearing supports a relatively large rotor gravity, and has the advantages of reliable performance and favorable control.

Description

A radial magnetic bearing with large bearing capacity

technical field

The invention relates to a non-contact magnetic suspension bearing, in particular to a radial magnetic bearing with large bearing capacity, which can be used as a non-contact support for rotating parts in mechanical equipment such as motors and machine tools.

Background technique

The magnetic levitation technology applied to ground equipment often requires radial magnetic bearings to support large rotor gravity, such as magnetic levitation high-speed motors, magnetic levitation energy storage flywheels, etc. At present, the radial magnetic levitation shaft structure used for ground support mainly includes the following types: one is pure electromagnetic bearing, which relies on the magnetic pulling force generated by the electromagnetic field to overcome the gravity of the rotor and the disturbing force received. This type of magnetic bearing has a large volume, uses a large current, and consumes a large amount of power. Especially when the bearing capacity is large, the copper consumption of the coil will rise sharply. The second is a passive magnetic bearing, which uses the attraction or repulsion between permanent magnets to generate levitation force. The magnetic bearing of this structure does not consume power, but its stiffness and damping are uncontrollable, and it generally requires permanent magnets to be installed on the rotor, so it is not suitable for high-speed rotating equipment. The third is the permanent magnet bias magnetic bearing. This kind of magnetic bearing uses the magnetic field generated by the permanent magnet to bear the main bearing capacity, and the electromagnetic field provides the auxiliary adjustment force. Therefore, this kind of magnetic bearing can greatly reduce the control current and reduce the loss. However, the structure of each offset magnetic pole of the traditional permanent magnet offset radial magnetic bearing is symmetrical, and the permanent magnetic force of each offset magnetic pole cancels each other in each degree of freedom. In some large rotating equipment, the rotor is usually suspended in the center position. At this time The permanent magnet bias magnetic bearing still needs to pass a large current to generate a large unilateral magnetic pull to overcome gravity, so the volume and power consumption of this type of magnetic bearing are still considerable. In view of the above reasons, existing magnetic bearing structures cannot meet the requirement of large constant bearing capacity in ground applications.

Contents of the invention

The technical problem of the present invention is: to overcome the deficiencies of the prior art, to provide a radial magnetic bearing with large bearing capacity that utilizes permanent magnetic force to overcome gravity, and can adjust electromagnetic force for active control, has small volume and low power consumption.

One of the technical solutions of the present invention is: a radial magnetic bearing with a large bearing capacity, which consists of a permanent magnet, a stator magnetic ring on the control side, a stator core on the control side, an excitation coil, a rotor core on the control side, a magnetic ring on the load-bearing side stator, and a load-bearing The large end of the side stator core, the small end of the load-bearing side stator core, the load-bearing side rotor core, and the rotor magnetic ring. The stator core is divided into left and right ends, which are the control side and the load-bearing side. The control side stator core includes X, Y positive and negative The four stator poles in the direction are connected by the yoke. Each stator pole is wound with an excitation coil. The large end of the stator core on the load-bearing side is a long axial stator pole, and the small end of the stator core on the load-bearing side is a short axis. The outside of the stator core on the control side is the stator magnetic ring on the control side, the large end of the stator core on the load-bearing side and the small end of the stator core on the load-bearing side are the stator magnetic rings on the load-bearing side, and the permanent magnet is located on the control side in the axial direction. Between the ring and the load-bearing side magnetic ring, the inside of the control side stator core is the control side rotor core, the inside of the load-bearing side stator core big end and the load-bearing side stator core small end is the load-bearing rotor core, the control side stator core inner surface and the control side A certain gap is left on the outer surface of the rotor core to form an air gap on the control side. A certain gap is left between the large end of the rotor core on the load-bearing side, the inner surface of the small end of the rotor core on the load-bearing side, and the outer surface of the rotor core on the load-bearing side to form an air gap on the load-bearing side. The rotor magnetic ring is installed inside the rotor core on the control side and the rotor core on the load-bearing side, and connects the rotor cores on both sides to form a magnetic path. The radial magnetic bearing with large bearing capacity is characterized in that the axial length of the small end of the stator core on the load-bearing side is 0.4 to 0.7 times that of the large end of the stator core on the load-bearing side. The permanent magnet is an axial ring, magnetized in the axial direction, and made of rare earth permanent magnet material or ferrite permanent magnet material. The large end of the stator core on the load-bearing side, the small end of the stator core on the load-bearing side, the stator magnetic ring on the control side, the stator magnetic ring on the load-bearing side, and the rotor magnetic ring are all made of materials with good magnetic properties, such as electrical pure iron, 1J50 or silicon steel. Any kind is made. The length of the air gap on the control side is 0.5 to 1 times the length of the air gap on the load-bearing side.

The principle of the above solution is: the present invention divides the radial magnetic bearing into two parts, the load-bearing side and the control side. The load-bearing side is used to overcome the gravity of the rotor, and the control side is used to overcome the disturbance force received by the rotor. The permanent magnet passes through the stator magnetic ring on the control side, the stator core on the control side, the air gap on the control side, the rotor core on the control side, the magnetic ring on the rotor, the rotor core on the load-bearing side, the air gap on the load-bearing side, and the big end and small end of the stator core on the load-bearing side. The stator magnetic ring at the end and load-bearing side constitutes a magnetic circuit. The electromagnetic magnetic circuit forms a loop on the stator core on the control side, the air gap on the control side, and the rotor core on the control side. On the load-bearing side, due to the different axial lengths of the magnetic poles of the two stator cores, the permanent magnet magnetic circuits generate different magnitudes of permanent magnetic pulling forces at the air gaps of the large and small two ends of the iron cores respectively. It is used to overcome the gravity of the rotor; on the control side, the permanent magnetic circuit generates a bias magnetic field at the air gaps corresponding to the four stator cores, and the electromagnetic magnetic circuit generates an adjustment magnetic field at the air gap. Bearing the magnetic force, the control side only needs to bear the disturbance force received by the rotor. Therefore, compared with the existing permanent magnet bias radial magnetic bearing structure with symmetrical structures at both ends, the levitation current of this structure is small, and the bearing volume is also small . The permanent magnet magnetic circuit of the present invention is: the magnetic flux starts from the N pole of the permanent magnet, passes through the stator magnetic ring on the control side, the stator core on the control side, the air gap on the control side, the rotor core on the control side, and the inner magnetic ring to the rotor on the load-bearing side The iron core and the air gap on the load-bearing side are divided into two paths, which respectively pass through the large end of the stator core on the load-bearing side and the small end of the stator core on the load-bearing side, and the external conducting magnet on the load-bearing side returns to the S pole of the permanent magnet to form the main magnetic circuit of the magnetic suspension bearing, as shown in Figure 1 shown. The electromagnetic magnetic circuit takes the magnetic flux generated after the excitation coil of the X positive direction magnetic pole is energized as an example: the stator magnetic pole in the X positive direction, the air gap in the X positive direction, and the rotor core on the control side are divided into three paths through the X negative direction, Y positive direction and After the air gap in the negative direction of Y, the stator magnetic pole corresponding to each air gap returns to the magnetic pole in the positive direction of X to form a closed loop, as shown in Figure 3.

The second technical solution of the present invention is: radial magnetic bearing with large bearing capacity, composed of permanent magnet, control side stator magnetic ring, control side stator core, excitation coil, control side rotor core, load bearing side stator magnetic ring, load bearing The large end of the stator core on the side, the small end of the stator core on the load-bearing side, the rotor core on the load-bearing side, and the rotor magnetic ring. The stator core is divided into left and right ends, which are the control side and the load-bearing side respectively. The stator core on the control side contains 4 stator poles in the positive and negative directions of X and Y, which are connected by a yoke. Each stator pole is wound with an excitation coil. The big end of the stator core on the load-bearing side is a pole with a long arc length Stator magnetic poles, the small end of the stator core on the load-bearing side is a stator magnetic pole with a shorter pole arc length, and the pole arc length of the small end is generally 0.4 to 0.7 times that of the large end. The outside of the stator core on the control side is the stator magnetic ring on the control side, the large end of the stator core on the load-bearing side and the small end of the stator core on the load-bearing side are the stator magnetic rings on the load-bearing side, and the permanent magnets are axially located between the magnetic ring on the control side and the load-bearing side. Between the magnetic rings, inside the stator core on the control side is the rotor core on the control side, inside the large end of the stator core on the load-bearing side and the small end of the stator core on the load-bearing side is the rotor core on the load-bearing side, the inner surface of the stator core on the control side and the outer surface of the rotor core on the control side A certain gap is left to form the air gap on the control side. There is a certain gap between the large end of the rotor core on the load-bearing side, the inner surface of the small end of the rotor core on the load-bearing side, and the outer surface of the rotor core on the load-bearing side to form an air gap on the load-bearing side. Air gap on the control side Generally, it is 0.5 to 1 times the air gap on the load-bearing side. The rotor magnetic ring is installed inside the rotor core on the control side and the rotor core on the load-bearing side, and connects the rotor cores on both sides to form a magnetic path.

The principle of the above solution is: the present invention divides the radial magnetic bearing into two parts, the load-bearing side and the control side. The load-bearing side is used to overcome the gravity of the rotor, and the control side is used to overcome the disturbance force received by the rotor. The permanent magnet passes through the stator magnetic ring on the control side, the stator core on the control side, the air gap on the control side, the rotor core on the control side, the magnetic ring on the rotor, the rotor core on the load-bearing side, the air gap on the load-bearing side, and the big end and small end of the stator core on the load-bearing side. The stator magnetic ring at the end and load-bearing side constitutes a magnetic circuit. The electromagnetic magnetic circuit forms a loop on the stator core on the control side, the air gap on the control side, and the rotor core on the control side. On the load-bearing side, due to the inconsistency of the pole arc lengths of the two stator core poles, the permanent magnet magnetic circuits generate different permanent magnet pulls at the air gaps of the large and small poles at both ends, and the unilateral magnetic pull of the rotor after the two forces are combined It is used to overcome the gravity of the rotor; on the control side, the permanent magnetic circuit generates a bias magnetic field at the air gaps corresponding to the four stator cores, and the electromagnetic magnetic circuit generates an adjustment magnetic field at the air gap. Bearing the magnetic force, the control side only needs to bear the disturbance force received by the rotor. Therefore, compared with the existing permanent magnet bias radial magnetic bearing structure with symmetrical structures at both ends, the levitation current of this structure is small, and the bearing volume is also small . The permanent magnet magnetic circuit of the present invention is: the magnetic flux starts from the N pole of the permanent magnet, passes through the stator magnetic ring on the control side, the stator core on the control side, the air gap on the control side, the rotor core on the control side, and the inner magnetic ring to the rotor on the load-bearing side The iron core and the air gap on the load-bearing side are divided into two paths, which respectively pass through the large end of the stator core on the load-bearing side and the small end of the stator core on the load-bearing side, and the external conducting magnet on the load-bearing side returns to the S pole of the permanent magnet to form the main magnetic circuit of the magnetic suspension bearing, as shown in Figure 4 shown. The electromagnetic magnetic circuit takes the magnetic flux generated by the magnetic pole excitation coil in the Y direction as an example: the stator pole in the positive direction in Y, the air gap in the positive direction in Y, the rotor core on the control side, the air gap in the negative direction in Y, the magnetic pole in the negative direction in Y direction, the rotor core return in the control side To the Y positive direction magnetic pole constitutes a closed loop, as shown in Figure 5.

Compared with the prior art, the present invention has the advantages that: the present invention divides the radial magnetic bearing into two parts, the bearing side and the control side. There is no excitation coil at the magnetic pole on the load-bearing side, and the two magnetic poles are used to generate unilateral magnetic pull through a structure with inconsistent areas, so that the load-bearing side only needs a small magnetic pole area to overcome the large gravity. Therefore, compared with the existing permanent magnet bias radial magnetic bearing structure with symmetrical structures on both sides, when applied to the same load-bearing occasion, the structure has reduced volume, reduced weight, and reduced four excitation magnets. coil, which improves the reliability of the system. At the same time, since the weight of the rotor is completely borne by the load-bearing side of the radial magnetic bearing, the control side only needs to pass a small current to maintain the stable suspension of the rotor. Therefore, another advantage of this structure is that the floating current is small and the copper loss is small.

Description of drawings

Fig. 1 is an axial sectional view of a radial magnetic bearing with a large bearing capacity, one of the technical solutions of the present invention;

Fig. 2 is a structure diagram of a stator core on the load-bearing side of a large-capacity radial magnetic bearing, one of the technical solutions of the present invention;

Fig. 3 is an axial end view of the control side of the large-capacity radial magnetic bearing, one of the technical solutions of the present invention and the second;

Fig. 4 is an axial sectional view of a radial magnetic bearing with a large bearing capacity of the second technical solution of the present invention;

Fig. 5 is an axial end view of the load-bearing side of the large-capacity radial magnetic bearing of the second technical solution of the present invention.

Detailed ways

As shown in Figure 1, it is a permanent magnet bias inner rotor radial magnetic bearing with unequal axial lengths of the magnetic poles on the load-bearing side of one of the technical solutions of the present invention, which is the basic form of the present invention. It consists of a permanent magnet 1, 1 control side stator magnetic ring 2, 1 control side stator core 3, 4 control side excitation coils 4, 1 control side rotor magnetic ring, 1 load bearing side stator magnetic ring 7, 1 load side stator The large end of the iron core 8, the small end 9 of the stator iron core on the load-bearing side, the rotor iron core 11 on the load-bearing side, and the magnetic conducting ring 12 of the rotor are composed. The stator core 3 on the control side includes four stator poles in the X and Y directions at one end of the magnetic bearing. The poles are connected by a yoke. Each stator pole on the control side is wound with an excitation coil 4. It is the magnetic permeable ring 2 of the stator on the control side, as shown in FIG. 3 . The large end 8 of the stator core on the load-bearing side and the small end 9 of the stator core on the load-bearing side form two stator magnetic poles on the Y direction at the other end of the magnetic bearing. The magnetic poles are connected in the middle of the core through yokes with different axial lengths. The axial length of the small end 9 is 0.4 to 0.7 times that of the large end 8, and the specific value is determined by the weight of the rotor. The heavier the rotor, the smaller the value, as shown in FIG. 2 . The large end 8 of the stator core on the load-bearing side and the small end 9 of the stator core on the load-bearing side are outside the stator magnetic ring 7 on the load-bearing side, and the permanent magnet 1 is located between the stator magnetic ring 2 on the control side and the stator magnetic ring 7 on the load-bearing side in the axial direction . Inside the control side stator core 3 is the control side rotor core 6, there is a certain gap between the inner surface of the control side stator core 3 and the outer surface of the control side rotor core 6, forming the control side air gap 5, the load-bearing side stator core big end 8, load-bearing Inside the small end 9 of the side stator core is the load-bearing rotor core 11, the large end 8 of the load-bearing stator core, the inner surface of the small end 9 of the load-bearing stator core and the outer surface of the load-bearing rotor core 11 leave a certain gap to form a load-bearing air gap 10. The air gap on the control side is 0.5 to 1 times the air gap on the load-bearing side. The rotor magnetically permeable ring 12 is installed inside the rotor core 6 on the control side and the rotor core 11 on the load-bearing side, and connects the rotor core 6 on the control side to the rotor core 11 on the load-bearing side. connected to form a magnetic path.

As shown in Figure 4, it is a permanent magnet bias inner rotor radial magnetic bearing with unequal lengths of load-bearing magnetic pole pole arcs of the second technical solution of the present invention, which consists of a permanent magnet 1 and a control-side stator for magnetic conduction Ring 2, 1 stator core on the control side 3, 4 excitation coils on the control side 4, 1 rotor magnetic ring on the control side, 1 stator magnetic ring on the load-bearing side 7, 1 big end of the stator core on the load-bearing side 8, 1 The load-bearing side stator core small end 9, one load-bearing rotor core 11, and one rotor magnetic conducting ring 12 are composed. The stator core 3 on the control side includes four stator poles in the X and Y directions at one end of the magnetic bearing. The poles are connected by a yoke. Each stator pole on the control side is wound with an excitation coil 4. It is the magnetic permeable ring 2 of the stator on the control side, as shown in FIG. 3 . The large end 8 of the stator core on the load-bearing side and the small end 9 of the stator core on the load-bearing side form two stator poles on the Y direction at the other end of the magnetic bearing. 0.4 to 0.7 times the big end 8, the specific value is determined by the weight of the rotor, the heavier the rotor, the smaller the value, as shown in Figure 5. The large end 8 of the stator core on the load-bearing side and the small end 9 of the stator core on the load-bearing side are outside the stator magnetic ring 7 on the load-bearing side, and the permanent magnet 1 is located between the stator magnetic ring 2 on the control side and the stator magnetic ring 7 on the load-bearing side in the axial direction . Inside the control side stator core 3 is the control side rotor core 6, there is a certain gap between the inner surface of the control side stator core 3 and the outer surface of the control side rotor core 6, forming the control side air gap 5, the load-bearing side stator core big end 8, load-bearing Inside the small end 9 of the side stator core is the load-bearing rotor core 11, the large end 8 of the load-bearing stator core, the inner surface of the small end 9 of the load-bearing stator core and the outer surface of the load-bearing rotor core 11 leave a certain gap to form a load-bearing air gap 10. The air gap on the control side is 0.5 to 1 times the air gap on the load-bearing side. The rotor magnetically permeable ring 12 is installed inside the rotor core 6 on the control side and the rotor core 11 on the load-bearing side, and connects the rotor core 6 on the control side to the rotor core 11 on the load-bearing side. connected to form a magnetic path.

The large end 8 of the stator core on the load-bearing side, the small end 9 of the stator core on the load-bearing side, the stator magnetic ring 2 on the control side, the stator magnetic ring 7 on the load-bearing side, and the rotor magnetic ring 12 used in the above-mentioned technical solutions of the present invention all use magnetic properties. Made of good materials, such as electrical pure iron, various carbon steels, cast iron, cast steel, alloy steel, 1J50 and 1J79 and other magnetic materials. The stator core 3 on the control side, the rotor core 6 on the control side and the rotor core 11 on the load-bearing side can be formed by stamping and stacking electrical thin steel plates with good magnetic properties, such as electrical pure iron, electrical silicon steel plates DR510, DR470, DW350, 1J50, and 1J79. become. The material of the permanent magnet 1 is a rare earth permanent magnet or a ferrite permanent magnet with good magnetic properties, and the permanent magnet 1 is an axial ring, which is magnetized along the axial direction. Exciting coil 4 is formed by dipping paint and drying after being wound with a good conductive electromagnetic wire.

Claims (10)

1. large bearing capacity radial direction magnetic bearing, by permanent magnet (1), control side stator magnetic guiding loop (2), control side stator core (3), field coil (4), control side rotor core (6), load-bearing side stator magnetic guiding loop (7), the big end of load-bearing side stator core (8), load-bearing side stator core small end (9), load-bearing side rotor core (11), rotor magnetic guiding loop (12) is formed, it is characterized in that: stator core is divided into two ends, the left and right sides, be respectively control side and load-bearing side, control side stator core (3) comprises X, 4 magnetic pole of the stator on the positive negative direction of Y, connect by yoke portion between them, each magnetic pole of the stator is wound with field coil (4), the big end of load-bearing side stator core (8) is that a major axis is to magnetic pole of the stator, load-bearing side stator core small end (9) is that a minor axis is to magnetic pole of the stator, control side stator core (3) outside is a control side stator magnetic guiding loop (2), big end of load-bearing side stator core (8) and load-bearing side stator core small end (9) are outside to be load-bearing side stator magnetic guiding loop (7), permanent magnet (1) is presented axially between control side magnetic guiding loop (2) and the load-bearing side magnetic guiding loop (7), control side stator core (3) inside is control side rotor core (6), big end of load-bearing side stator core (8) and load-bearing side stator core small end (9) are inner to be load-bearing side rotor core (11), control side stator core (3) internal surface and control side rotor core (6) outer surface leave certain clearance, form control side air gap (5), the big end of load-bearing side rotor core (8), load-bearing side rotor core small end (9) internal surface and load-bearing side rotor core (11) outer surface leave certain clearance, form load-bearing side air gap (10), rotor magnetic guiding loop (12) is installed in control side rotor core (6) and load-bearing side rotor core (11) inside, and the both sides rotor core coupled together, form flux path.

2. large bearing capacity radial direction magnetic bearing according to claim 1 is characterized in that: the axial length of load-bearing side stator core small end (9) is 0.4～0.7 times of the big end of load-bearing side stator core (8).

3. large bearing capacity radial direction magnetic bearing according to claim 1, it is characterized in that: the big end of described load-bearing side stator core (8), load-bearing side stator core small end (9), control side stator magnetic guiding loop (2), load-bearing side stator magnetic guiding loop (7) and rotor magnetic guiding loop (12) all adopt the good material of magnetic property, make as any one of electrical pure iron, 1J50 or silicon steel.

4. large bearing capacity radial direction magnetic bearing according to claim 1 is characterized in that: described permanent magnet (1) is an axial annulus, magnetizes vertically.

5. large bearing capacity radial direction magnetic bearing according to claim 1 is characterized in that: control side air gap (5) length is 0.5～1 times of load-bearing side air gap (10) length.

6. large bearing capacity radial direction magnetic bearing, by permanent magnet (1), control side stator magnetic guiding loop (2), control side stator core (3), field coil (4), control side rotor core (6), load-bearing side stator magnetic guiding loop (7), the big end of load-bearing side stator core (8), load-bearing side stator core small end (9), load-bearing side rotor core (11), rotor magnetic guiding loop (12) is formed, it is characterized in that: stator core is divided into two ends, the left and right sides, be respectively control side and load-bearing side, control side stator core (3) comprises X, 4 magnetic pole of the stator on the positive negative direction of Y, connect by yoke portion between them, each magnetic pole of the stator is wound with field coil (4), the big end of load-bearing side stator core (8) is a big polar arc magnetic pole of the stator, load-bearing side stator core small end (9) is a little polar arc magnetic pole of the stator, control side stator core (3) outside is a control side stator magnetic guiding loop (2), big end of load-bearing side stator core (8) and load-bearing side stator core small end (9) are outside to be load-bearing side stator magnetic guiding loop (7), permanent magnet (1) is presented axially between control side magnetic guiding loop (2) and the load-bearing side magnetic guiding loop (7), control side stator core (3) inside is control side rotor core (6), big end of load-bearing side stator core (8) and load-bearing side stator core small end (9) are inner to be load-bearing side rotor core (11), control side stator core (3) internal surface and control side rotor core (6) outer surface leave certain clearance, form control side air gap (5), the big end of load-bearing side rotor core (8), load-bearing side rotor core small end (9) internal surface and load-bearing side rotor core (11) outer surface leave certain clearance, form load-bearing side air gap (10), rotor magnetic guiding loop (12) is installed in control side rotor core (6) and load-bearing side rotor core (11) inside, and the both sides rotor core coupled together, form flux path.

7. large bearing capacity radial direction magnetic bearing according to claim 6 is characterized in that: the length of pole arc of load-bearing side stator core small end (9) is 0.4～0.7 times of the big end of load-bearing side stator core (8).

8. large bearing capacity radial direction magnetic bearing according to claim 6, it is characterized in that: the big end of described load-bearing side stator core (8), load-bearing side stator core small end (9), control side stator magnetic guiding loop (2), load-bearing side stator magnetic guiding loop (7) and rotor magnetic guiding loop (12) all adopt the good material of magnetic property, make as any one of electrical pure iron, 1J50 or silicon steel.

9. large bearing capacity radial direction magnetic bearing according to claim 6 is characterized in that: described permanent magnet (1) is an axial annulus, magnetizes vertically.

10. large bearing capacity radial direction magnetic bearing according to claim 6 is characterized in that: control side air gap (5) length is 0.5～1 times of load-bearing side air gap (10) length.

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