CN110165824A - Magnetic suspension motor - Google Patents

Abstract

The invention relates to the technical field of magnetic suspension and provides a magnetic suspension motor. The magnetic levitation motor includes a rotor shaft, an axial magnetic bearing is arranged coaxially on the outer side of the rotor shaft, the first end of the rotor shaft is an output end, and a magnetic adsorption unit is arranged on the outer side of the second end of the rotor shaft. The magnetic adsorption unit generates an adsorption force along the axial direction of the rotor shaft, and the second end of the rotor shaft is in contact with the magnetic adsorption unit; the outer side of the rotor shaft is also provided with a device for detecting the instability of the rotor shaft. sensor, when the rotor shaft is unstable, the axial magnetic bearing feeds a control current to control the second end of the rotor shaft to detach from the magnetic adsorption unit. When the rotor shaft becomes unstable, it is ensured that the instability is suppressed.

Description

Magnetic levitation motor

technical field

The invention belongs to the technical field of magnetic levitation, in particular to a magnetic levitation motor.

Background technique

Small electric motors are the most common form of converting electrical energy into mechanical energy and have a wide range of applications in household appliances and industry. The traditional motor mainly includes the motor stator part, the motor rotor part, the rotor support bearing and the casing part. The motor stator part and the motor rotor part are connected by mechanical bearings or have mechanical contact, so there is mechanical friction during the movement of the electronic rotor. Mechanical friction will reduce the speed of the rotor to a certain extent. At the same time, mechanical friction will generate noise, wear components, generate heat and cause other negative problems, which will eventually shorten the service life of the motor. Therefore, in order to achieve ultra-high speed operation and long life of the equipment, Clean and oil-free must adopt a non-contact support method in the motor, that is, a magnetic suspension support method.

However, the magnetic levitation motor used in the prior art may suffer from rotor instability, which is caused by various reasons, such as external force interference, load change, and control instability. After the instability, the rotor will nutate and precess chaotically inside the motor due to the influence of the gyro effect, and the high-frequency disordered impact will cause damage to the mechanical body of the motor. The solution to the instability is to reduce the speed of the rotor quickly to reduce the damage caused by the impact of the high-speed rotor. But usually the magnetic bearing is also in a state of loss of control when it is unstable, so it is generally used to quickly cut off the power and let the protection bearing withstand the high-frequency impact of the rotor. In order to avoid instability as much as possible, the bearing capacity of the magnetic bearing is designed to be very large (high rigidity), so as to resist the instability caused by the disturbance of the rotor. The price is to sacrifice volume and materials, making the magnetic levitation motor large and complex.

Contents of the invention

The purpose of the present invention is to provide a magnetic levitation motor. When the rotor shaft is unstable, the axial position of the rotor shaft is adjusted to ensure that the instability is suppressed.

In order to achieve the above object, the present invention adopts the following technical solutions: a magnetic levitation motor, including a rotor shaft, an axial magnetic bearing is coaxially arranged on the outside of the rotor shaft, the first end of the rotor shaft is an output end, and the A magnetic adsorption unit is provided outside the second end of the rotor shaft, and the magnetic adsorption unit generates an adsorption force on the rotor shaft along its axial direction, and the second end of the rotor shaft is in contact with the magnetic adsorption unit; The outer side of the rotor shaft is also provided with a sensor for detecting the instability of the rotor shaft. When the rotor shaft is unstable, the axial magnetic bearing passes a control current to control the second end of the rotor shaft to detach from the magnetic adsorption unit.

Optionally, the second end of the rotor shaft is in point contact with the magnetic adsorption unit.

Optionally, a spherical protrusion is provided at the center of the second end of the rotor shaft.

Optionally, the axial magnetic bearing is arranged on the outer circumference of the second end of the rotor shaft, the axial magnetic bearing includes a magnetically permeable ring, and an annular groove is opened on the inner side of the magnetically permeable ring, and inside the annular groove Windings are provided, and a thrust plate is extended from the outer periphery of the second end of the rotor shaft, and the thrust plate is located in the annular groove.

Optionally, the magnetic adsorption unit includes an annular permanent magnet disposed corresponding to the second end of the rotor shaft, the annular permanent magnet is disposed outside the magnetic conduction ring, and the inner ring of the annular permanent magnet is provided with a wear-resistant plate.

Optionally, an annular sleeve extends from the outer groove wall of the annular groove, the annular permanent magnet is sleeved on the outer periphery of the annular sleeve, and the wear-resistant plate is arranged on the inner ring of the annular sleeve.

Optionally, the sensor includes an axial displacement sensor, an installation groove is opened on the inner surface of the wear-resistant plate, and the axial displacement sensor is arranged in the installation groove.

Optionally, a radial magnetic bearing and a motor stator core are arranged coaxially on the outer side of the rotor shaft, two radial magnetic bearings are provided, and the two radial magnetic bearings are symmetrically arranged on the motor Both sides of the stator core.

Optionally, a casing is also included, and the motor stator core, the radial magnetic bearing and the axial magnetic bearing are all arranged on the inner wall of the casing.

Optionally, the sensor includes a radial displacement sensor, the radial displacement sensor is arranged on the inner wall of the housing, and the radial displacement sensor is located between the radial magnetic bearing and the stator core of the motor .

Compared with the prior art, when the rotor shaft is unstable, a control current is passed to the axial magnetic bearing at this time, and the axial force generated by the control current is opposite to the adsorption force generated by the magnetic adsorption unit, and the axial magnetic bearing generates a shaft The axial force makes the rotor shaft detach from the magnetic adsorption unit, so as to ensure that the rotor shaft maintains a stable suspension in the axial direction, and ensures that the rear end of the rotor shaft does not have any contact with the magnetic adsorption unit, avoiding the magnetic force when the rotor shaft is unstable. The collision between the adsorption unit units also avoids the reaction force of the magnetic adsorption unit on the unstable rotor from being applied to the magnetic bearing to increase the burden on the magnetic bearing, and the axial magnetic bearing can also work normally so that the rotor shaft is in the axial direction Maintaining a stable suspension is more conducive to the stabilization of the rotor shaft from an unstable state.

Description of drawings

Fig. 1 is a sectional view one of the present invention;

Fig. 2 is a sectional view two of the present invention (rotor shaft is not shown);

Fig. 3 is a schematic diagram of cooperation between an axial magnetic bearing and a magnetic adsorption unit according to the present invention.

Reference signs:

1. Motor stator core; 2. Radial magnetic bearing; 3. Axial magnetic bearing; 31. Magnetic ring; 32. Annular groove; 33. Winding; 34 Annular sleeve; 4. Rotor shaft; 41. Spherical 42, thrust plate; 5, magnetic adsorption unit; 51, annular permanent magnet; 52, wear-resistant plate; 6, shell; 7, axial displacement sensor; 8, radial displacement sensor.

Detailed ways

In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the described embodiments are some, not all, embodiments of the present invention. The specific embodiments described here are only used to explain the present invention, but not to limit the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention belong to the protection scope of the present invention.

As shown in Figure 1, a magnetic levitation motor provided by an embodiment of the present invention includes a rotor shaft 4, an axial magnetic bearing 3 is arranged coaxially on the outside of the rotor shaft 4, the first end of the rotor shaft 4 is an output end, and the rotor shaft A magnetic adsorption unit 5 is provided outside the second end of 4, and the magnetic adsorption unit 5 generates an adsorption force along the axial direction of the rotor shaft 4, and the second end of the rotor shaft 4 is in contact with the magnetic adsorption unit 5; the outer side of the rotor shaft 4 is also A sensor is provided for detecting the instability of the rotor shaft 4 . When the rotor shaft 4 is unstable, the axial magnetic bearing 3 passes a control current to control the second end of the rotor shaft 4 to detach from the magnetic adsorption unit 5 .

When the motor is working, the radial support and positioning of the rotor shaft 4 are realized by the radial magnetic bearing 2, and the axial movement of the rotor shaft 4 is restricted by the magnetic adsorption unit 5. The adsorption force of the magnetic adsorption unit 5 should be designed to be large enough to make the axial The magnetic bearing 3 allows the rotor shaft 4 to be in stable contact with the magnetic adsorption unit 5 without passing through an electric current. However, when the adsorption force of the magnetic adsorption unit 5 is insufficient, the axial magnetic bearing 3 can also pass through a small adsorption current to assist the magnetic adsorption unit 5 to apply force to the rotor shaft 4, so that the rotor shaft 4 is in contact with the magnetic adsorption unit 5 Stable high-speed rotation. The most preferred solution is to adopt a solution that does not need to pass current to the axial magnetic bearing 3, because the axial magnetic bearing 3 is not energized, and the bearing magnetic bearing 3 will never run out of control when the rotor shaft 4 becomes unstable. When the rotor shaft 4 is unstable, a control current is passed to the axial magnetic bearing 3 at this time, the axial force generated by the control current is opposite to the adsorption force generated by the magnetic adsorption unit 5, and the axial magnetic bearing 3 generates an axial force The rotor shaft 4 is detached from the magnetic adsorption unit 5, thereby ensuring that the rotor shaft 4 maintains a stable suspension in the axial direction, and ensuring that the rear end of the rotor shaft 4 does not have any contact with the magnetic adsorption unit 5, thereby avoiding the unstable state of the rotor shaft 4 Collide with the magnetic adsorption unit unit 5, and simultaneously eliminate the same-frequency reaction force exerted by the magnetic adsorption unit unit 5 on the unstable rotor shaft 4; in the prior art, the radial magnetic bearing 2 and the axial magnetic bearing The bearings 3 are all energized and work. Once the magnetic bearing loses stability, the magnetic bearing is also in an out-of-control state, which cannot effectively suppress the chaotic vibration of the rotor shaft 4 in the radial and axial directions. However, once the rotor shaft 4 loses stability in this application, because of the The axial magnetic bearing 3 has no current or a small adsorption current before the instability, so after the rotor shaft 4 becomes unstable, the axial magnetic bearing 3 of the present application will not lose control, and the axial magnetic bearing 3 will not lose control. The bearing 3 can also work normally so that the instability of the rotor shaft 4 is suppressed, and it is kept stable in the axial direction, which is more conducive to the stabilization of the rotor shaft 4 from the unstable state.

In addition, it should be noted that the technology for detecting the instability of the rotor shaft 4 in the prior art is very mature, and sensors are usually installed in the magnetic levitation motor to detect whether the rotation state of the rotor shaft 4 is stable. When the radial displacement exceeds a certain range and the frequency of displacement changes is high, the system determines that the rotor shaft 4 is unstable. At this time, the radial magnetic bearing 2 and the axial magnetic bearing 3 will be powered off through the system control. Of course, in addition to this method, there are also Vibration sensors and other means known to those skilled in the art can be used to detect the instability of the rotor shaft 4 , which will not be repeated in this application.

In some embodiments, the contact between the second end of the rotor shaft 4 and the magnetic adsorption unit 5 is a point contact. Although the rotor shaft 4 rotates at a high speed in the working state, since the rotor shaft 4 is in point contact with the magnetic adsorption unit 5, the friction between the two is very small, which will not affect the performance and service life of the magnetic levitation motor.

In some embodiments, as shown in FIG. 1 , a spherical protrusion 41 is disposed at the center of the second end of the rotor shaft 4 . Ensure that the point contact position is located on the axis of the rotor shaft 4, thereby ensuring that the direction of the adsorption force on the rotor shaft 4 is axial; the spherical protrusion 41 can be integrally formed with the rotor shaft 4, eliminating the need for the spherical protrusion 41 and The connection of the rotor shaft 4 is easy to process, and the connection is reliable, which ensures the service life. It is also possible to set a spherical protrusion 41 at the center of the second end of the magnetic adsorption unit 5 corresponding to the rotor shaft 4; The protrusion 41 can also be detachably connected with the rotor shaft 4 or the magnetic adsorption unit 5 .

In some embodiments, as shown in FIG. 2 , the axial magnetic bearing 3 is arranged on the outer circumference of the second end of the rotor shaft 4 , the axial magnetic bearing 3 includes a magnetic conduction ring 31 , and an annular groove is opened on the inner side of the magnetic conduction ring 31 32 , a winding 33 is arranged in the annular groove 32 , and a thrust disc 42 is provided extending from the outer circumference of the second end of the rotor shaft 4 , and the thrust disc 42 is located in the annular groove 32 . The way of axial magnetic bearing 3 in this scheme is the way that winding 33 cooperates with magnetic conducting ring 31 to energize. Of course, the way of permanent magnet bias axial magnetic bearing in the prior art can also be used. Of course, axial magnetic bearing 3 does not It must be arranged on the outer circumference of the second end of the rotor shaft 4 , and may also be other positions corresponding to the rotor shaft 4 .

In some embodiments, as shown in FIGS. 2 and 3 , for the axial magnetic bearing 3 is arranged on the outer circumference of the second end of the rotor shaft 4 , the magnetic adsorption unit 5 includes an annular permanent magnet disposed corresponding to the second end of the rotor shaft 4 51 , the annular permanent magnet 51 is arranged on the outer side of the magnetic permeable ring 31 , and the inner ring of the annular permanent magnet 51 is provided with a wear-resistant plate 52 . The arrangement form of the magnetic force adsorption unit 5 is not limited only to the manner in which the annular permanent magnet 51 and the wear-resistant plate 51 described above cooperate, if the arrangement of the axial magnetic bearing 3 is not close to the magnetic force absorption unit 5, the magnetic force can also be The adsorption unit 5 completely adopts permanent magnets, because the magnetic force lines of the magnetic force adsorption unit 5 and the magnetic force lines of the axial magnetic bearing 3 will not interfere; of course, the magnetic force adsorption unit 5 can also adopt the method of magnetizer plus winding electrification. When the motor is working, The rotor shaft 4 is adsorbed when the power is turned on, and the rotor shaft 4 is not adsorbed when the power is turned off after the instability occurs, so that the axial magnetic bearing 3 is connected to the control current to adjust the axial position of the rotor shaft 4.

In some embodiments, as shown in FIG. 2 and FIG. 3 , an annular sleeve 34 extends from the groove wall on the outer side of the annular groove 32 , the annular permanent magnet 51 is sleeved on the outer periphery of the annular sleeve 34 , and the wear-resistant plate 52 is arranged on the annular sleeve 34 . Set of 34 inner rings. In order to facilitate the installation of the magnetic adsorption unit 5, an annular sleeve 34 is extended outside the magnetically conductive ring 31, and the annular permanent magnet 51 is sleeved on the outer periphery of the annular sleeve 34 to generate adsorption force on the rotor shaft 4, but at the same time it will not affect the axial direction. The energization of the magnetic bearing 3 works normally, and the material of the wear-resistant plate 52 can adopt non-magnetic and wear-resistant materials such as ceramics or carbon fibers. In addition, the wear-resistant plate 52 can be set in a step shape, and its small diameter section is snapped into the annular sleeve 34. The large-diameter section snaps into place at the end of the annular sleeve 34 .

In some embodiments, as shown in FIG. 2 and FIG. 3 , the sensor includes an axial displacement sensor 7 , an installation groove is opened on the inner surface of the wear plate 52 , and the axial displacement sensor 7 is arranged in the installation groove. In order to detect the axial displacement of the rotor shaft 4 , an installation groove is opened on the wear plate 52 , and the axial displacement sensor 7 faces the second end of the rotor shaft 4 .

In some embodiments, as shown in Figures 1 and 2, a radial magnetic bearing 2 and a motor stator core 1 are arranged coaxially on the outer side of the rotor shaft 4, two radial magnetic bearings 2 are provided, and two diameters The magnetic bearings 2 are symmetrically arranged on both sides of the stator core 1 of the motor. A radial magnetic bearing 2 is provided on both sides of the stator core 1 of the motor for radially supporting the rotor shaft 4 to ensure the stability of the rotor shaft 4 .

In some embodiments, as shown in FIG. 1 and FIG. 2 , a housing 6 is further included, and the motor stator core 1 , the radial magnetic bearing 2 and the axial magnetic bearing 3 are all arranged on the inner wall of the housing 6 .

In some embodiments, as shown in Figure 1 and Figure 2, the sensor includes a radial displacement sensor 8, the radial displacement sensor 8 is arranged on the inner wall of the housing 6, and the radial displacement sensor 8 is between the radial magnetic bearing 2 and the motor stator Between core 1. The radial displacement sensor 8 is located in the radial direction of the rotor shaft 4 and is used to detect the radial displacement of the rotor shaft 4. Of course, the radial displacement sensor 8 can also be arranged at other positions in the housing 6. In some other arrangements Among them, the inner side of the radial magnetic bearing 2 is uniformly arranged with windings, and the radial displacement sensor 8 can be arranged between two adjacent windings.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. A magnetic levitation motor, characterized in that: comprise a rotor shaft (4), the outer coaxial arrangement of the rotor shaft (4) has an axial magnetic bearing (3), the first end of the rotor shaft (4) is the output end, and the second end of the rotor shaft (4) is provided with a magnetic adsorption unit (5), and the magnetic adsorption unit (5) generates an adsorption force along the axial direction of the rotor shaft (4), The second end of the rotor shaft (4) is in contact with the magnetic adsorption unit (5); The outer side of the rotor shaft (4) is also equipped with a sensor for detecting the instability of the rotor shaft (4). When the rotor shaft (4) is unstable, the axial magnetic bearing (3) is connected to the control current control The second end of the rotor shaft (4) is separated from the magnetic adsorption unit (5). 2. The magnetic levitation motor according to claim 1, characterized in that: the contact between the second end of the rotor shaft (4) and the magnetic adsorption unit (5) is a point contact. 3. The magnetic levitation motor according to claim 2, characterized in that: a spherical protrusion (41) is provided at the center of the second end of the rotor shaft (4). 4. The magnetic levitation motor according to claim 1, characterized in that: the axial magnetic bearing (3) is arranged on the outer circumference of the second end of the rotor shaft (4), and the axial magnetic bearing (3) includes a magnetically conductive Ring (31), the inner side of the magnetic conduction ring (31) is provided with an annular groove (32), and a winding (33) is arranged in the annular groove (32), the second of the rotor shaft (4) A thrust plate (42) is arranged on the outer periphery of the end, and the thrust plate (42) is located in the annular groove (32). 5. The magnetic levitation motor according to claim 4, characterized in that: the magnetic force adsorption unit (5) includes an annular permanent magnet (51) arranged at the second end of the corresponding rotor shaft (4), and the annular permanent magnet ( 51) It is arranged on the outside of the magnetic conduction ring (31), and the inner ring of the annular permanent magnet (51) is provided with a wear-resistant plate (52). 6. The magnetic levitation motor according to claim 5, characterized in that: an annular sleeve (34) extends from the outer wall of the annular groove (32), and the annular permanent magnet (51) is sleeved on the The outer circumference of the annular sleeve (34), the wear plate (52) is arranged on the inner ring of the annular sleeve (34). 7. The magnetic levitation motor according to claim 6, characterized in that: the sensor includes an axial displacement sensor (7), the inner surface of the wear plate (52) is provided with a mounting groove, and the axial displacement sensor (7) Arranged in the installation groove. 8. The magnetic levitation motor according to claim 1, characterized in that: a radial magnetic bearing (2) and a motor stator core (1) are arranged coaxially on the outside of the rotor shaft (4), the radial There are two magnetic bearings (2), and the two radial magnetic bearings (2) are symmetrically arranged on both sides of the motor stator core (1). 9. The magnetic levitation motor according to claim 8, characterized in that: it also includes a housing (6), the motor stator core (1), the radial magnetic bearing (2) and the axial magnetic bearing (3) are all It is arranged on the inner wall of the casing (6). 10. The magnetic levitation motor according to claim 9, characterized in that: the sensor includes a radial displacement sensor (8), and the radial displacement sensor (8) is arranged on the inner wall of the housing (6), so The radial displacement sensor (8) is located between the radial magnetic bearing (2) and the motor stator core (1).