Rotor structure and rotor assembly of surface-mounted permanent magnet synchronous motor
Technical Field
The utility model belongs to the technical field of the surface-mounted permanent magnet synchronous motor, refer in particular to a surface-mounted permanent magnet synchronous motor's rotor structure and rotor subassembly.
Background
The new energy vehicle is more and more popular with its advantage of environmental protection, and its used auxiliary drive system such as automobile-used air compressor machine, a steering system has more requirement to driving motor inside: high reliability, high performance, high adaptability, low cost, low weight, high response speed, etc.
The surface-mounted permanent magnet synchronous motor (SPM) is widely applied to the field due to the advantages of high efficiency, high overload capacity, high dynamic response speed and the like.
The existing surface-mounted permanent magnet synchronous motor mainly has two types of rotor structure: the inner surface and the outer surface of the magnetic steel are arcs, the radius of the arc of the inner surface is larger than that of the arc of the outer surface so as to form a section shape with a thick middle part and thinner two ends, and the structure can effectively reduce torque fluctuation and positioning torque so as to reduce vibration noise, but the structure causes great waste of magnetic steel materials and higher cost; in another surface-mounted magnetic steel, the circle centers of an inner arc and an outer arc of the magnetic steel are at the same point and coincide with the circle center of the shaft hole, the radius of the outer arc is larger than that of the inner arc, the magnetic steel is equal in thickness, and the structure has large torque fluctuation and is easy to generate vibration noise.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a can effectively reduce motor tooth's socket torque, reduce winding harmonic and tooth harmonic, to a great extent reduces motor torque and fluctuates, reduces motor vibration noise and promotes the operation stationarity, can also reduce cost's table pastes formula PMSM's rotor structure and rotor subassembly simultaneously.
The purpose of the utility model is realized like this:
the utility model provides a surface mounting type PMSM's rotor structure, includes rotor punching and the magnet steel of setting on rotor punching, evenly distributed has a plurality of on rotor punching's global the magnet steel, and rotor punching middle part has been seted up the shaft hole, the magnet steel bottom is the cambered surface, the centre of a circle of cambered surface with there is the deviation between the shaft hole center, for eccentric settings.
The peripheral surface of the rotor punching sheet is provided with a plurality of magnetic steel positions, each magnetic steel position comprises a second cambered surface attached to the bottom of the corresponding magnetic steel, and the highest points of the second cambered surfaces of the plurality of magnetic steel positions are positioned on the same excircle; the magnetic steel comprises N-pole magnetic steel and S-pole magnetic steel, and the N-pole magnetic steel and the S-pole magnetic steel are alternately arranged on the magnetic steel position.
Further set up as, adjacent two the shaping has the magnetic bridge between the magnet steel position, the magnet steel position is 2 times of the motor pole pair number with the quantity of magnetic bridge, the centre of a circle of second cambered surface with the distance deviation is the delta between the shaft hole center, and the radius of second cambered surface is R1, the diameter of excircle is D, and the relation between delta, R1, D is: r1 +/-delta is D/2, wherein delta is more than or equal to 0.05D and less than or equal to 0.2D.
The magnetic steel is further arranged to be parallel grooves, the groove edges on two sides of the magnetic steel are parallel to each other, the magnetic steel is parallel magnetic steel, and the side lines on two sides of the magnetic steel are parallel to each other.
The magnetic steel is a dovetail groove, straight lines of groove edges on two sides of the magnetic steel are crossed with each other, the magnetic steel is a dovetail magnetic steel, and straight lines of side lines on two sides of the magnetic steel are crossed with each other.
And further setting that chamfered structures are formed on two sides of the rear part of the cambered surface of the magnetic steel back to the magnetic steel position.
The magnetic steel comprises a front part facing the magnetic steel position arc surface and a rear part facing away from the magnetic steel position arc surface, the front part and the rear part are both arc-shaped, and the radius of the front part is the same as or different from that of the rear part.
The central line of the weight-reducing groove, the magnetic steel position and the central line of the magnetic steel are positioned on the same straight line, the weight-reducing groove comprises a first outer side edge, a second outer side edge, a first side edge, a second side edge and an inner side edge, and the first outer side edge and the second outer side edge are connected through smooth transition of arc edges; the inner side edges are arc-shaped, and the inner side edges of the weight reduction grooves are positioned on the same inner circle.
The included angle formed by the intersection of extension lines of the first outer side edge and the second outer side edge is β, wherein the included angle is equal to or larger than β and equal to or smaller than 135 degrees, the diameter of the inner circle is d1, the diameter of the shaft hole is d, the shortest distance between two adjacent weight reduction grooves is t, the relation between d1, d and t is d 1-d +2t, and t is equal to or larger than 0.1d and equal to or smaller than 0.2 d.
The shortest distance between the top point of the arc edge and the first arc surface at the bottom of the magnetic steel is x, the thickness of the thickest part in the middle of the magnetic steel is m, and x is not less than m and not more than 2.5 m.
The utility model also provides a rotor component of the surface-mounted permanent magnet synchronous motor, which comprises a plurality of rotor structures which are axially overlapped and arranged,
the plurality of rotor punching sheets are coaxially arranged, and the axial center lines of the magnetic bridges of the plurality of rotor punching sheets are all positioned on the same straight line;
or two adjacent rotor punching sheets are arranged in a staggered manner in different directions, and the axial center lines of the magnetic bridges of the odd rotor punching sheet and the even rotor punching sheet are respectively positioned on the same straight line;
or two adjacent rotor punching sheets are staggered in the same direction.
Compared with the prior art, the utility model outstanding and profitable technological effect is:
the utility model provides a rotor structure, eccentric settings between magnet steel and the rotor punching, the first cambered surface in magnet steel bottom has different centre of a circle with the shaft hole promptly, different centre of a circle designs and makes to produce inhomogeneous air gap (be unequal air gap) between the stator and the rotor, unequal air gap can make motor magnetic field waveform more approach the sine wave, make harmonic content descend, be favorable to forming sinusoidal back electromotive force, the harmonic distortion rate reduces, thereby can effectively reduce motor tooth's socket torque and torque fluctuation, thereby reduce motor vibration noise and promote the stationarity of operation; meanwhile, the weight and the cost of the whole rotor punching sheet are greatly reduced due to the design of the weight reduction grooves.
Drawings
Fig. 1 is one of the structural diagrams of the rotor structure of the present invention.
Fig. 2 is a schematic view of the structure of the rotor sheet of the present invention.
Fig. 3 is a schematic view of the structure of the weight-reducing groove of the present invention.
Fig. 4 is a reference diagram of magnetic field distribution of the magnetic steel of the present invention.
Fig. 5 is a schematic view of the parallel groove structure of the present invention.
Fig. 6 is a simplified structure diagram of the parallel magnetic steel of the present invention.
Fig. 7 is a schematic view of a dovetail groove according to the present invention.
Fig. 8 is a schematic view of the dovetail-shaped magnetic steel of the present invention.
Fig. 9 is a schematic structural diagram of a third embodiment of the magnetic steel of the present invention.
Fig. 10 is a schematic view of a first embodiment of a rotor assembly according to the present invention.
Fig. 11 is a schematic view of a second embodiment of the rotor assembly of the present invention.
Fig. 12 is a schematic view of a third embodiment of a rotor assembly according to the present invention.
FIG. 13 is a graph comparing back-emf for equal and unequal air gaps over the same time.
FIG. 14 is a graph comparing the ratio of the harmonics to the equal and unequal airgap harmonics in the fundamental.
FIG. 15 is a graph comparing torque ripple for the same operating power for a non-eccentric, and eccentric skewed pole arrangement of the rotor assembly.
Fig. 16 is a plan view of the magnetic steel and the rotor core being eccentrically disposed.
Fig. 17 is a second schematic view of the rotor structure of the present invention.
Detailed Description
The invention will be further described in the following with reference to specific embodiments thereof, with reference to the accompanying drawings, in which fig. 1-17:
a rotor structure of a surface-mounted permanent magnet synchronous motor comprises a rotor punching sheet 1 and a magnetic steel 2 arranged on the rotor punching sheet 1, wherein a shaft hole 6 is formed in the middle of the rotor punching sheet 1, the bottom of the magnetic steel 2 is a first cambered surface, a deviation exists between the circle center of the first cambered surface and the center of the shaft hole 6, namely the magnetic steel and the rotor punching sheet are eccentrically arranged, and a connecting key is formed on the shaft hole 6 and is connected with a rotating shaft through a key or in an interference fit manner; evenly seted up a plurality of being used for placing on rotor punching 1 global magnet steel position 3 of magnet steel 2, the shaping has magnetic bridge 4 between two adjacent magnet steel position 3, magnet steel position 3 is 2 times of the motor pole pair number with magnetic bridge 4' S quantity (the motor pole number is the motor, and the magnetic pole divides the N utmost point and the S utmost point, and general magnetic pole number appears in pairs, like 2 utmost point motors, 4 utmost point motors generally call 1N utmost point and 1S utmost point a pair of magnetic pole, also is that the motor pole pair number is 1), magnet steel 2 includes N utmost point magnet steel and S utmost point magnet steel, and N utmost point magnet steel and S utmost point magnet steel set up in turn in magnet steel position 3.
The bottom of the magnetic steel position 3 is a second cambered surface attached to the first cambered surface at the bottom of the magnetic steel 2, the radius of the second cambered surface is R1, the center of the cambered surface and the center of the shaft hole 6 have deviation, the deviation value is delta, and the highest points of the cambered surfaces at the bottoms of the magnetic steel positions 3 are positioned on the same excircle 7; the diameter of the outer circle 7 is D, and the relation among delta, R1 and D is as follows: r1 ± δ is D/2, where, through experiments, δ is 0.05D ≦ δ ≦ 0.2D, which is an optimal structure, and the above structure with deviation is favorable for forming a low-cost unequal air gap motor structure, and the unequal air gaps can make the motor magnetic field waveform closer to a sine wave (as shown in fig. 13, a comparison graph of back electromotive force in the same time of equal air gap and unequal air gap is shown, where a curve a is equal air gap and a curve B is unequal air gap); unequal air gaps can effectively reduce the cogging torque of the motor, reduce the winding harmonic (as shown in fig. 14, a comparison graph of the harmonic times of the equal air gaps and the unequal air gaps and the proportion of the harmonic in the fundamental wave) and the tooth harmonic, and as is obvious from fig. 13 and 14, when the unequal air gaps are adopted, the magnetic field is weakened, the counter electromotive force is reduced, but the proportion of the counter electromotive force harmonic amplitude in the fundamental wave is greatly reduced, and the sine of the counter electromotive force is optimized, so that the torque fluctuation during the operation of the motor can be effectively reduced, the torque fluctuation of the motor can be greatly reduced, the vibration noise of the motor can be reduced, and the operation stability of the motor can be.
The magnetic steel position 3 can be a groove (shown in fig. 1-2) formed on the circumferential surface of the rotor punching sheet 1, the magnetic steel is embedded in the groove, and the joint of two adjacent grooves protrudes outwards to form the magnetic bridge; the magnetic steel position 3 can also be an outward convex edge (as shown in fig. 17), the magnetic steel is attached to the surface of the convex edge, and the joint of two adjacent convex edges is inward concave to form the magnetic bridge.
As a first embodiment of the magnetic steel position and the magnetic steel, as shown in fig. 5, the magnetic steel position 3 is a parallel groove, the groove edges 31 on both sides of the magnetic steel position 3 are parallel to each other, as shown in fig. 6, the magnetic steel 2 is a parallel magnetic steel, and the side lines 21 on both sides of the magnetic steel 2 are parallel to each other.
As a second embodiment of the magnetic steel position and the magnetic steel, as shown in fig. 7, the magnetic steel position 3 is a dovetail groove, straight lines of groove edges 32 on both sides of the magnetic steel position 3 intersect with each other to form an included angle γ, as shown in fig. 8, the magnetic steel 2 is a dovetail magnetic steel, straight lines of side lines 22 on both sides of the magnetic steel 2 intersect with each other to form an included angle γ 1, γ is γ 1, and an angle between γ and γ 1 can be set according to actual requirements.
As a third embodiment of the magnetic steel, in addition to the above two embodiments, as shown in fig. 9, the two sides of the magnetic steel 2 facing away from the rear portion 23 of the arc surface of the magnetic steel position 3 are chamfered, and a chamfered structure 25 is formed, so that the cogging torque and the torque ripple can be further reduced, and the weight of the magnetic steel can also be reduced.
The magnetic steel 2 comprises a front part 24 facing the arc surface of the magnetic steel position 3 and a rear part 23 facing away from the arc surface of the magnetic steel position 3, the front part 24 and the rear part 23 are arc-shaped, the radius of the front part 24 is the same as that of the rear part 23, and the arc-shaped parts are arranged into arc-shaped parts with the same radius, so that deviation can be formed between circle centers of the arc parts at the front part and the rear part of the magnetic steel 2, different circle center designs enable unequal air gaps to be generated between a stator and a rotor, the unequal air gaps can enable the waveform of a motor magnetic field to be closer to a sine wave, the harmonic content is reduced, the sine counter potential is favorably formed, the harmonic distortion rate is reduced, the cogging torque and the. In the practical use process, the arcs of the front part and the rear part can be set to be unequal in radius, and although the structure with unequal air gaps can be formed, the cost is much higher than that of magnetic steel with the same radius.
The magnetic steel 2 and the rotor punching sheet 1 are arranged eccentrically, namely, a certain distance exists between the circle center of the arc surface of the front portion of the magnetic steel sheet and the circle center of the rotor punching sheet, the two are not concentric, as shown in fig. 16 (the letter o is the circle center of the rotor punching sheet, and the letter o' is the circle center of the arc surface of the front portion of the magnetic steel sheet), non-uniform air gaps (namely, unequal air gaps) are generated between the stator and the rotor due to different circle center designs, the unequal air gaps can enable the waveform of a magnetic field of the motor to be closer to a sine wave, the harmonic content is reduced, the sine counter electromotive force is favorably formed, the harmonic distortion rate is reduced, the cogging torque and the torque fluctuation of.
A plurality of lightening slots 5 are annularly and uniformly distributed on the end face of the rotor punching sheet 1, a pin hole 9 is further formed between every two adjacent lightening slots 5, the center line of each lightening slot 5, the magnetic steel position 3 and the center line of the magnetic steel 2 are positioned on the same straight line, namely, the lightening slots 5 are arranged on the center line of the magnetic steel, as shown in fig. 4 (the curve with an arrow in the figure is a magnetic line), a magnetic circuit runs from the N pole of the magnetic steel to the S pole of the magnetic steel, a loop (magnetic circuit) is formed by the stator teeth, the stator yoke, the rotor yoke and the like, the magnetic circuit can find that the magnetic line of force of the magnetic steel at each pole is symmetrical about the center position of the magnetic steel, and few magnetic lines of force pass near the center line, namely, the magnetic density at the position is very small, so that the lightening slots 5 arranged at the position can.
As shown in fig. 3, the weight-reducing slots 5 are pentagonal, and include a first outer side 51, a second outer side 52, a first side 53, a second side 54 and an inner side 55, an included angle formed by the intersection of extension lines of the first outer side 51 and the second outer side 52 is β, the first outer side 51 and the second outer side 52 are connected in a smooth transition manner through an arc 56, the shortest distance between the vertex of the arc 56 and the outer circle 7 is x, the thickness of the thickest part of the magnetic steel 2 is m, wherein m is not less than 2.5m, 100 degrees is not less than β degrees or not more than 135 degrees, the inner side 55 is arc, the inner sides 55 of the weight-reducing slots 5 are located on the same inner circle 8, the diameter of the inner circle 8 is d1, the diameter of the shaft hole 6 is d, the shortest distance between two adjacent weight-reducing slots 5 (the distance between the second side 54 of the weight-reducing slot and the first side 53 of the adjacent weight-reducing slot) is t, the relationship between d1, d1 is d +2t, wherein the distance between the second side of the weight-reducing slot is not more than 0.1, and the rotor inertia of the motor can not more than 0.2.
The utility model provides a surface mounting type PMSM's rotor subassembly, includes the foretell rotor structure of a plurality of axial stack arrangements, first rotor subassembly embodiment: as shown in fig. 10, a plurality of rotor sheets 1 are coaxially arranged, and axial center lines of magnetic bridges 4 of the plurality of rotor sheets 1 are all located on the same straight line.
A second rotor assembly embodiment: adjacent two rotor punching sheets 1 are arranged in a staggered manner in different directions, as shown in fig. 11, axial center lines of magnetic bridges 4 of the odd-numbered rotor punching sheet 1 and the even-numbered rotor punching sheet 1 are respectively located on the same straight line, namely, a certain angle is staggered between the (M + 1) th rotor punching sheet and the (M) th rotor punching sheet, and the (M + 2) th rotor punching sheet and the (M) th rotor punching sheet are not staggered at an angle.
In the third embodiment of the rotor assembly, two adjacent rotor sheets 1 are arranged in a staggered manner in the same direction, as shown in fig. 12, if the M +1 th rotor sheet and the M th rotor sheet are staggered by a certain angle α, and the M +2 th rotor sheet and the M th rotor sheet are staggered by an angle 2 α.
Above-mentioned first rotor subassembly embodiment is the rotor subassembly that the rotor eccentric arrangement did not carry out the oblique utmost point range, second and third rotor subassembly embodiment is the rotor subassembly of eccentric settings and oblique utmost point range, as shown in fig. 15, it does not eccentric settings to provide the rotor (ordinary rotor on the market, the condition that magnet steel cambered surface and rotor punching piece set up with the centre of a circle), eccentric settings and eccentric oblique utmost point set up the torque fluctuation contrast map under the same operating mode power (in the figure, C is the current general rotor and does not eccentric settings, D is the rotor eccentric settings, E is the rotor eccentric settings and the oblique utmost point sets up), it is obvious to see out from fig. 15 that the adoption eccentric oblique utmost point rotor subassembly compares ordinary not eccentric settings or eccentric settings more can further reduce the torque ripple, reduce the vibration noise, reduce magnet steel eddy current loss simultaneously, improve motor efficiency.
The basic principles and the main features of the invention and the advantages of the invention have been shown and described above. It will be understood by those skilled in the art that the present invention is not limited to the above embodiments, and that the foregoing embodiments and descriptions are provided only to illustrate the principles of the present invention without departing from the spirit and scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.