CN111306070A - A centrifugal pump with rotor integrated vane axial flux permanent magnet motor - Google Patents

Abstract

The invention discloses a centrifugal pump including an axial magnetic flux permanent magnet motor with rotor integrated blades, comprising a casing and an axial magnetic flux permanent magnet synchronous motor installed therein. The casing includes a stator casing and a rotor casing, and the axial magnetic flux permanent magnet motor includes a stator and a rotor. The stator includes a stator core and a coil, the rotor includes a rotor yoke, a bushing and a permanent magnet, and the rotor simultaneously constitutes an impeller of a centrifugal pump. The permanent magnets are inserted into the bushing with an interference fit as the individual vanes of the centrifugal pump impeller. When working, the stator winding generates a rotating magnetic field, which interacts with the permanent magnetic field on the impeller to drive the impeller to rotate. During this process, the fluid medium flows through the flow channels between the blades, and the pressure increases. The centrifugal pump of the present invention has the advantages of small axial size, small number of components, and high power density. At the same time, it uses the fluid medium to cool the heating parts of the motor, ensuring that the centrifugal pump can be used in extreme environments. It also solves the problem of wind noise caused by thin-walled blades of traditional centrifugal pumps.

Description

A centrifugal pump with rotor integrated vane axial flux permanent magnet motor

technical field

The invention relates to a centrifugal pump, in particular to a centrifugal pump containing an axial magnetic flux permanent magnet motor with rotor integrated blades, and belongs to the technical field of motors and fluid machinery.

Background technique

With the continuous acceleration of the electrification process of vehicles, the use of electric drive for on-board subsystems has gradually become the mainstream. Among them, the motor-driven pump and fan system occupies a large proportion. In order to increase the battery life, electric vehicles require each subsystem to have a high power density, and at the same time, it should operate stably when the ambient temperature changes greatly. At the same time, the overall reliability index of the vehicle is higher, and reducing the number of components in each subsystem is an important direction to improve reliability, reduce assembly workload and labor costs.

Secondly, electric vehicles require the drive motors of each subsystem to have a certain torque overload capability, especially in pumps that transport fluid media with high viscosity. Considering the harsher installation environment of the pump and fan subsystems, the heat dissipation design of the drive motor is particularly difficult. In addition, in order to improve the comfort of the occupants, the requirements for the in-vehicle environment, especially the in-vehicle noise, are more stringent. The study found that the noise between the thin-walled blades in the impeller of the pump and the fan and the fluid medium is an important source of vehicle noise. The suppression of this part of the noise can significantly reduce the noise level of the vehicle.

The existing pump and fan subsystems are generally of a separate structure, and the rotor of the motor and the impeller need to be fixed coaxially, or the impeller needs to be fixed on the rotor of the motor. These two types of fixing systems are bulky, especially the axial dimension, which is inconvenient to install in electric vehicles. The larger volume reduces the power density and efficiency of the pump and fan system. At the same time, there are many system components, the sealing is difficult, and the reliability is reduced. On the other hand, the torque pulsation of the drive motor in the existing pump and fan is relatively large, and the vibration and noise problems caused by this are difficult to solve. When the vibration of the motor is conducted to the impeller, it will further increase the wind noise generated by the impeller.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is: to provide a centrifugal pump with an axial magnetic flux permanent magnet motor with rotor integrated blades, the impeller of the centrifugal pump and the rotor of the axial magnetic flux permanent magnet motor are integrated into the design, which overcomes the problem of deficiencies in the existing technology.

The present invention adopts the following technical solutions for solving the above-mentioned technical problems:

A centrifugal pump with a rotor integrated vane axial flux permanent magnet motor, comprising a housing and an axial flux permanent magnet motor incorporated therein, the housing comprising a rotor housing and a stator housing, both of which are Sealed by bolts and/or adhesives, the rotor casing is involute along the flow direction of the fluid medium, and the rotor casing has an outlet for the fluid medium, and the stator casing has an inlet for the fluid medium;

The axial flux permanent magnet motor includes a rotor and a stator, wherein the rotor includes a rotor yoke, a bushing and a permanent magnet, the rotor yoke is a disc-shaped structure, the bushing is a fan-shaped thin-walled structure, and the bushing is uniform along the circumferential direction Distributed on one side of the rotor yoke; the permanent magnet is a sector-shaped cylinder, its pole arc angle is smaller than the pole pitch of the rotor pole of the axial flux permanent magnet motor, and the two sides of the permanent magnet along the radial direction are arc-shaped , the inner and outer arcs of the permanent magnet are staggered along the circumferential direction, the permanent magnet is magnetized along the direction of the rotating shaft, and the polarity changes alternately along the circumferential direction; the inner shape of the bushing is the same as that of the permanent magnet, after the permanent magnet and the bushing are assembled A single blade constituting the centrifugal pump, the blades are evenly distributed on one side of the rotor yoke along the circumferential direction, and together with the rotor yoke constitute the impeller of the centrifugal pump, that is, the rotor;

The stator includes a stator core and a coil. A slot for placing the coil is machined on the stator core. The slot faces the impeller in the axial direction. The coil is embedded in the slot. An insulating material is arranged between the coil and the slot. It is potted with the stator iron core to form a torus stator, and the torus stator is press-fitted into the groove of the stator casing.

There is a space passing through in the radial direction between two adjacent blades, and the two opposite sides between the two adjacent blades, the surface of the rotor yoke facing the space, and the surface of the encapsulated annular stator facing the space together constitute a fluid. A single flow channel for the medium;

The impeller is connected to the rotor casing through radial bearings, and there is a gap between the impeller and the rotor casing. An axial thrust bearing is used to fix the impeller and the stator casing. The impeller and the stator are concentric, and there is a gap between the stator and the impeller in the axial direction.

As a preferred solution of the present invention, the shape of the outer edge of the rotor casing is determined by an Archimedes spiral.

As a preferred solution of the present invention, the bushing and the rotor yoke are integrally processed and formed, or the bushing and the rotor yoke are connected by welding, or a groove of the same shape as the bushing is machined on one side of the rotor yoke. A tight fit inserts the bushing into the groove.

As a preferred solution of the present invention, the permanent magnet and the bushing are assembled by interference fit, or fixed by gluing, or fixed by clamping, or fixed by bolts.

As a preferred solution of the present invention, the axial flux permanent magnet motor adopts a double-rotor single-stator structure, the stator adopts a yoke-free structure, and the stator includes a plurality of stator cores and coils wound on each stator core, The dual rotors are arranged on both sides of the stator in the axial direction.

Compared with the prior art, the present invention adopts the above technical scheme, and has the following technical effects:

1. The present invention integrates the impeller of the centrifugal pump with the rotor of the axial magnetic flux permanent magnet motor, and does not require an additional impeller and a connection device with the motor shaft. The number of system components and axial dimensions are greatly reduced, the structure is compact, and the reliability is increased. At the same time, the weight of the system is reduced, the power density is increased, and the overall efficiency is significantly improved. The existence of permanent magnets improves the efficiency and output torque of the motor, and has obvious advantages when pumping fluid media with high viscosity.

2. In the present invention, the fluid flows through the stator and rotor of the axial magnetic flux permanent magnet motor, which is easy to conduct the losses in the motor in time, which is beneficial to reduce the temperature rise of the rotor and the winding. Lower grade permanent magnets and/or lower cost winding materials can be used with the same magnetic properties and losses.

3. The bushing and the permanent magnet in the present invention adopt an interference fit, which greatly increases the rigidity of the centrifugal pump blade and reduces the wind noise caused by the interaction between the thin-walled blade and the fluid.

4. The inclined pole of the permanent magnet of the present invention greatly reduces the torque ripple, which is beneficial to reduce the vibration and noise of the motor.

Description of drawings

FIG. 1 is an overall structural diagram of a centrifugal pump including an axial flux permanent magnet motor with rotor integrated vanes according to the present invention.

Fig. 2 is a schematic diagram of the stator casing of the centrifugal pump of the present invention.

Figure 3 is a schematic diagram of the rotor casing of the centrifugal pump of the present invention.

4 is a schematic structural diagram of an axial flux permanent magnet motor of the present invention.

FIG. 5 is a schematic diagram of the rotor of the axial flux permanent magnet motor of the present invention.

6 is a schematic diagram of the permanent magnets on the rotor of the axial flux permanent magnet motor of the present invention.

FIG. 7 is a schematic diagram of the stator of the axial flux permanent magnet motor of the present invention.

FIG. 8 is a schematic diagram of the stator of the axial flux permanent magnet motor of the present invention after potting.

FIG. 9 is a schematic diagram of the flow channel and impeller of the centrifugal pump of the present invention.

Detailed ways

The technical solutions of the present invention will be further described below with reference to FIGS. 1 to 9 through specific embodiments. It should be pointed out that, in order to avoid obscuring the core technical features of the present invention in the description of the fine structures (for example, the fixing holes on the casing and the terminals of the motor windings), only the main features of the present invention are drawn in FIGS. 1 to 9 . Structure and implementation steps related to technical features. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, but not to be construed as a limitation of the present invention.

As shown in FIG. 1 , a centrifugal pump with an axial flux motor with rotor integrated vanes is composed of a casing 5 and a 10-pole 12-slot axial flux permanent magnet motor 6 installed therein.

As shown in FIG. 1 , FIG. 2 , FIG. 3 and FIG. 9 , the casing 5 is composed of a rotor casing 51 and a stator casing 52 , which are sealed by bolts and adhesives. The rotor casing 51 and the stator casing 52 are sealed structures molded from engineering plastics. The rotor casing 51 has an involute shape along the fluid flow direction. The inlet 11 for the fluid medium is left on the stator casing 52 , and the outlet 12 for the fluid medium is left on the rotor casing 51 . The shape of the outer edge 57 of the rotor case 51 and the flow channel 55 is determined by the Archimedes spiral.

As shown in FIGS. 4 and 5 , the axial flux permanent magnet motor 6 includes two parts, a rotor 2 and a stator 3 . The rotor 2 is composed of a rotor yoke 23 , a bushing 22 and a permanent magnet 21 . The rotor yoke 23 is a disc-shaped structure with a thickness of 6 mm. The bushing 22 is a fan-shaped thin-walled structure, and the part close to the rotation center is modified into a circular arc shape 25 to reduce local pressure loss. Ten bushings 22 are evenly distributed on the rotor yoke 23, and the rotor yoke 23 and the bushing 22 are integrally processed from magnetically conductive 45# steel. The bushing 22 and the rotor yoke 23 can be processed separately and connected by welding. Alternatively, a groove with the same shape as the bushing 22 is machined in the rotor yoke 23 , and the bushing 22 is inserted into the rotor yoke 23 and fixed by using an interference fit.

As shown in FIG. 6 , the permanent magnet 21 is a cylinder with a sector-shaped section, and its pole arc angle is 22.5°, which is smaller than the pole pitch of the magnetic poles in this embodiment, which is 36°. The sides 28 and 29 of the permanent magnet 21 in the radial direction are arc-shaped, and the shapes of the sides 28 and 29 are determined according to the fluid flow and pressure. The inner and outer arcs 26 and 27 of the permanent magnet 21 are staggered by 3.6° in the circumferential direction, so that the permanent magnet 21 has a slanted pole effect in the circumferential direction. The permanent magnets 21 are sintered ferrite materials, which are magnetized along the direction of the rotation axis, and the polarities of the ten permanent magnets 21 change alternately along the circumferential direction. The permanent magnet 21 and the bushing 22 can also be fixed in other ways, such as gluing, clamping, and bolting.

As shown in FIG. 5 and FIG. 9 , the inner shape of the bushing 22 is the same as the outer shape of the permanent magnet 21 , and the bushing 22 and the permanent magnet 21 are assembled by interference fit. The assembled magnetic pole 21 and the bushing 22 constitute a single vane 70 of the centrifugal pump. The ten vanes 70 are evenly distributed on the rotor yoke 23 in the circumferential direction, and together with the rotor yoke 23 constitute the impeller of the centrifugal pump (that is, the axial magnetic flux permanent Magnetic synchronous motor rotor 2). In order to reduce the possibility of corrosion of the permanent magnets, the permanent magnets can be sealed with a non-magnetically conductive sheet of the same shape and size as the bushing, and the non-magnetically conductive sheet and the bushing are fixed by welding.

As shown in FIG. 2 , FIG. 7 , and FIG. 8 , the stator 3 includes a stator core 31 formed by winding a 0.5 mm electrical steel sheet and a coil 33 made of enameled wires. The stator core 31 is machined by wire electric discharge cutting to form 12 slots 32 for placing the motor winding coils 33 , and the slots 32 are axially opposite to the impeller. A total of 12 coils of the three-phase motor are wound in sequence and embedded in the slot 32 , and an insulating material (not shown) is arranged between the coil 33 and the slot 32 . In order to reduce the fluid flow resistance, epoxy resin 41 is used to encapsulate the coil 33 and the stator core 31 into a whole annular stator 42 , and then press-fit into the annular groove 56 in the stator casing 52 . In this embodiment, the diameter of the annular stator 42 is the same as that of the impeller, which is 90 mm. The diameter of the encapsulated annular stator 42 may also be different from that of the impeller.

As shown in FIG. 5 , there are gaps penetrating in the radial direction between the vanes 70 . The sides of two adjacent vanes 70 , the space-facing face of the rotor yoke 23 and the space-facing face of the annular stator 42 together constitute a single flow channel 24 for the fluid medium. The cross-sectional area of the flow channel gradually increases in the radial direction. Guide vanes may be machined between the vanes 70 of the impeller to optimize fluid flow and reduce pressure losses.

As shown in FIG. 2 , FIG. 3 , FIG. 7 and FIG. 9 , the impeller is connected to the rotor casing 51 through the radial bearing 53 , and the gap between the impeller and the rotor casing 51 is 0.35 mm. At the same time, in order to offset the axial magnetic pulling force, an axial thrust bearing 54 is used to fix the impeller and the stator casing 52 . The radial bearing 53 and the axial thrust bearing 54 realize the support and positioning of the impeller in the axial and radial directions, and ensure the concentricity between the impeller and the stator 3 of the motor. The gap between the stator 3 and the impeller in the axial direction is 0.5mm, and the smaller the gap, the better on the premise of ensuring the safety of assembly and operation.

As shown in FIG. 4 and FIG. 9 , during normal operation, the three-phase sinusoidal current flows into the three-phase windings of the axial flux permanent magnet motor 6 , and a rotating electric current is generated in the air gap 8 between the stator 3 and the rotor 2 . armature magnetic field. The rotation direction of the armature magnetic field is consistent with the involute direction of the flow channel 55 , which is clockwise in FIG. 9 . The armature magnetic field interacts with the permanent magnetic field generated by the permanent magnet 21 to drive the impeller to rotate, and the blades 70 on the impeller drive the fluid to flow in the radial direction under the action of centrifugal force, and flow out from the outlet 12 of the centrifugal pump through the interval and the flow channel 55 . During this process, the pressure of the fluid is increased, realizing the pressurizing function of the pump. In order to facilitate processing and manufacturing, the shapes of the rotor casing 51 and the flow channel 55 can be determined by using the equilateral element method.

In order to reduce the axial unbalanced force, the axial flux permanent magnet motor 6 may adopt a double rotor and single stator structure. The stator of the motor adopts a yoke-free structure, and is composed of a plurality of core units and coils 33 wound thereon. The double rotors are arranged on both sides of the stator in the axial direction, and the structure of the rotors is the same as above.

The above embodiments are only to illustrate the technical idea of the present invention, and cannot limit the protection scope of the present invention. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the present invention. Inside.

Claims (5)

1. a centrifugal pump containing a rotor-integrated vane axial flux permanent magnet motor, comprising a casing (5) and an axial flux permanent magnet motor (6) loaded therein, characterized in that the casing (5) comprising a rotor casing (51) and a stator casing (52), both of which are sealed by bolts and/or adhesives, the rotor casing (51) is involute along the flow direction of the fluid medium, and the rotor casing ( 51) An outlet (12) for fluid medium is left on the stator casing (52), and an inlet (11) for fluid medium is left on the stator casing (52); The axial flux permanent magnet motor (6) includes a rotor (2) and a stator (3), wherein the rotor (2) includes a rotor yoke (23), a bushing (22) and a permanent magnet (21), and the rotor yoke (23) is a disc-shaped structure, the bushing (22) is a fan-shaped thin-walled structure, and the bushing (22) is evenly distributed on one side of the rotor yoke (23) along the circumferential direction; the permanent magnet (21) has a cross-section of A sector-shaped cylinder, the pole arc angle of which is smaller than the pole pitch of the rotor poles of the axial flux permanent magnet motor (6), the two sides of the permanent magnet (21) in the radial direction are arc-shaped, and the inner and outer sides of the permanent magnet (21) are arc-shaped. The two arcs are staggered along the circumferential direction, the permanent magnet (21) is magnetized along the direction of the rotating shaft, and the polarity changes alternately along the circumferential direction; the inner shape of the bushing (22) is the same as that of the permanent magnet (21), and the permanent magnet ( 21) and the bushing (22) are assembled to form a single vane (70) of the centrifugal pump, the vanes (70) are evenly distributed on one side of the rotor yoke (23) along the circumferential direction, together with the rotor yoke (23) The impeller that constitutes the centrifugal pump is the rotor (2); The stator (3) includes a stator iron core (31) and a coil (33), a slot (32) for placing the coil (33) is machined on the stator iron core (31), and the slot (32) faces the impeller in the axial direction, The coil (33) is embedded in the slot (32), an insulating material is arranged between the coil (33) and the slot (32), and epoxy resin is used to encapsulate the coil (33) and the stator core (31) into a torus stator (42), the annular stator (42) is press-fitted into the annular groove (56) of the stator casing (52); There is a space passing through in the radial direction between two adjacent blades (70), two opposite sides between two adjacent blades (70), the surface of the rotor yoke (23) facing the space, and the potted ring The spaced facing faces of the body stator (42) together form a single flow channel (24) for the fluid medium; The impeller is connected to the rotor casing (51) through a radial bearing (53), and there is a gap between the impeller and the rotor casing (51). The impeller and the stator casing (52) are fixed by an axial thrust bearing (54). The impeller and the stator (3) are concentric, and there is a gap between the stator (3) and the impeller in the axial direction. 2. The centrifugal pump with rotor integrated vane axial flux permanent magnet motor according to claim 1, characterized in that, the shape of the outer edge (57) of the rotor casing (51) is formed by the Archimedes screw. line ok. 3. The centrifugal pump with rotor-integrated vane axial flux permanent magnet motor according to claim 1, wherein the bushing (22) and the rotor yoke (23) are integrally processed and formed, or the bushing (22) ) is connected with the rotor yoke (23) by welding, or a groove of the same shape as the bushing (22) is machined on one side of the rotor yoke (23), and the bushing (22) is embedded in the groove by interference fit. 4. The centrifugal pump containing the rotor-integrated vane axial flux permanent magnet motor according to claim 1, characterized in that, the permanent magnet (21) and the bushing (22) are assembled by interference fit, or by using glue Glue fixed assembly, or use snap-on fixed assembly, or use bolted fixed assembly. 5. The centrifugal pump containing the rotor-integrated vane axial flux permanent magnet motor according to claim 1, wherein the axial flux permanent magnet motor (6) adopts a double-rotor single-stator structure, and the stator adopts a In the yoke structure, the stator includes a plurality of stator iron cores and coils wound on each stator iron core, and the double rotors are arranged on both sides of the stator along the axial direction.

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