Permanent magnet synchronous motor and rotor pressing plate thereof

Abstract

The invention provides a permanent magnet synchronous motor and a rotor pressing plate thereof. A pressing plate body of the rotor pressing plate is made of a material with the magnetic permeability larger than a magnetic permeability threshold value, through holes corresponding to permanent magnets on a rotor iron core are formed in the pressing plate body, and the pressing plate body and the rotor iron core are staggered by a target angle in the axial direction, so that an overlapping area exists between partial areas of the permanent magnets and the pressing plate body; the magnetic flux leakage area of the pressing plate body is provided with a magnetic barrier, and the magnetic barrier is used for blocking the magnetic flux leakage path of the permanent magnet passing through the rotor pressing plate. According to the invention, the pressing plate body and the rotor iron core are staggered at the target angle in the axial direction, and the magnetic barrier is arranged in the magnetic flux leakage area of the pressing plate body, so that the magnetic flux leakage of the end part of the rotor can be effectively reduced, the great reduction of counter electromotive force is avoided, and the torque output of the motor under the same current excitation is ensured.

Description

Technical Field

[0001] The present disclosure relates to the technical field of motors, and in particular to a permanent magnet synchronous motor and a rotor pressure plate thereof. Background Art

[0002] Due to its advantages of high efficiency, high torque density, high power factor, etc., permanent magnet synchronous motors are widely used in various fields such as industry and household appliances. For permanent magnet synchronous motors, the magnets are inserted into the magnet slots inside the rotor core, and the rotor pressure plate is fixed to the end of the rotor core by rivets. The rotor pressure plate not only fixes the magnets in the axial direction, but also has a direct impact on the stability, noise control and thermal management of the motor. In the prior art, the rotor pressure plate material of the motor is usually stainless steel. The rotor pressure plate includes a pressure plate body, a shaft hole and a rivet hole. A special process is required to manufacture the stainless steel pressure plate, and its manufacturing cost and material cost are both relatively high. Summary of the invention

[0003] The technical problem to be solved by the present disclosure is to overcome the above-mentioned defects in the prior art and to provide a permanent magnet synchronous motor and a rotor pressure plate thereof.

[0004] The present invention solves the above technical problems through the following technical solutions:

[0005] In a first aspect, a rotor pressure plate is provided for use in a motor, wherein the motor further comprises a rotor core, and at least two permanent magnets are provided on the rotor core; a pressure plate body of the rotor pressure plate is made of a material having a magnetic permeability greater than a magnetic permeability threshold, and a through hole corresponding to each permanent magnet is provided on the pressure plate body, and the pressure plate body and the rotor core are axially staggered by a target angle so that a portion of each permanent magnet has an overlapping area with the pressure plate body; a magnetic barrier is provided in a leakage magnetic area of ​​the pressure plate body, and the magnetic barrier is used to block the leakage magnetic flux path of the permanent magnet through the rotor pressure plate.

[0006] Optionally, the through hole is in a sector ring shape, and the magnetic leakage area includes:

[0007] A first sub-region is located between two adjacent through holes; the shape of the magnetic barrier in the first sub-region is determined according to the shape of the permanent magnet facing the first sub-region;

[0008] and / or, a second sub-region located on one side of the inner arc of the through hole and facing the permanent magnet; the shape of the magnetic barrier in the second sub-region is determined according to the shape of the permanent magnet facing the second sub-region;

[0009] And / or, a third sub-region located on one side of the inner arc of the through hole and facing the region between the two permanent magnets.

[0010] Optionally, the shape of the first magnetic barrier located in the first sub-region is determined according to a first magnetic barrier arc, a second magnetic barrier arc, a third magnetic barrier arc and a fourth magnetic barrier arc connected end to end in sequence, and the first magnetic barrier arc, the second magnetic barrier arc, the third magnetic barrier arc and the fourth magnetic barrier arc have the following constraint relationship:

[0011] ; ; ;

[0012] Wherein, R1, R2, R3 and R4 are respectively the radii of the first inner arc, the first outer arc, the first magnetic barrier arc and the second magnetic barrier arc of the first permanent magnet directly opposite to the first magnetic barrier, and the centers of the first inner arc, the first outer arc, the first magnetic barrier arc and the second magnetic barrier arc are all the first center; a1 is the minimum distance from the first inner arc to the first magnetic barrier arc, a2 is the minimum distance from the first magnetic barrier arc to the second magnetic barrier arc, and a3 is the minimum distance from the first outer arc to the second magnetic barrier arc; h m is the thickness of the permanent magnet; R5 and R6 are respectively the radius of the second outer arc of the through hole close to the third magnetic barrier arc and the radius of the third magnetic barrier arc, and the centers of the second outer arc and the third magnetic barrier arc are both the second center; b1 is the minimum distance from the second outer arc to the third magnetic barrier arc; R7 and R8 are respectively the radius of the third outer arc of the through hole close to the fourth magnetic barrier arc and the radius of the fourth magnetic barrier arc, and the centers of the fourth magnetic barrier arc and the third outer arc are both the third center; b2 is the minimum distance from the third outer arc to the fourth magnetic barrier arc.

[0013] Optionally, an axial hole is further provided at the center of the pressing plate body; the angle formed by the center of the axial hole, the first center of the circle, and the second center of the circle is 30°; and / or the angle formed by the center of the axial hole, the first center of the circle, and the third center of the circle is 30°;

[0014] And / or, b1, b2, a1, a3, a2 all meet the minimum distances required for the mechanical strength of the rotor of the motor.

[0015] Optionally, an axial hole is further provided at the center of the pressing plate body; the shape of the second magnetic barrier located in the second sub-area is determined according to a fifth magnetic barrier arc, a sixth magnetic barrier arc, a seventh magnetic barrier arc and an eighth magnetic barrier arc which are sequentially connected end to end; the fifth magnetic barrier arc, the sixth magnetic barrier arc, the seventh magnetic barrier arc and the eighth magnetic barrier arc have the following constraint relationship:

[0016] ; ; ;

[0017] Among them, R9, R 10, R 11 and R 12 are respectively the radii of the second inner arc, the fourth outer arc, the fifth magnetic barrier arc and the sixth magnetic barrier arc of the permanent magnet directly facing the second magnetic barrier, and the centers of the second inner arc, the fourth outer arc, the fifth magnetic barrier arc and the sixth magnetic barrier arc are all the fourth center; d1 is the minimum distance from the second inner arc to the fifth magnetic barrier arc, d2 is the minimum distance from the fifth magnetic barrier arc to the sixth magnetic barrier arc, and d3 is the minimum distance from the fourth outer arc to the sixth magnetic barrier arc; h m is the thickness of the permanent magnet; R 14 , R ro are the radius of the seventh magnetic barrier arc and the outer diameter of the rotor core respectively. The rotor core and the seventh magnetic barrier arc are cocentric with the hole axis; c1 is the minimum distance from the outer edge of the rotor core to the seventh magnetic barrier arc; R 16 is the radius of the third inner arc of the through hole close to the eighth magnetic barrier arc, R 17 is the radius of the eighth magnetic barrier arc, the centers of the eighth magnetic barrier arc and the third inner arc are both the fifth center; c3 is the minimum distance from the third inner arc to the eighth magnetic barrier arc.

[0018] Optionally, the second sub-region includes two second magnetic barriers, and the two second magnetic barriers are symmetrically distributed about a target symmetry axis; the target symmetry axis is a symmetry axis of a permanent magnet that the two second magnetic barriers are facing respectively;

[0019] and / or, the distances from the fourth circle center and the fifth circle center to the center of the shaft hole are equal;

[0020] And / or, the angle formed by the center of the axial hole and the fourth center and the fifth center is 30°.

[0021] Optionally, the shape of the third magnetic barrier of the third sub-region is determined according to a ninth magnetic barrier arc, a tenth magnetic barrier arc, an eleventh magnetic barrier arc and a twelfth magnetic barrier arc which are connected end to end in sequence; the ninth magnetic barrier arc, the tenth magnetic barrier arc, the eleventh magnetic barrier arc and the twelfth magnetic barrier arc have the following constraint relationship:

[0022] ;

[0023] Among them, R 13 is the radius of the ninth magnetic barrier arc, the center of the ninth magnetic barrier arc is the fourth center; g1 is the minimum distance from the ninth magnetic barrier arc to the fourth outer arc; is the minimum distance from the eleventh magnetic barrier arc to the twelfth magnetic barrier arc; the eleventh magnetic barrier arc is concentric with the shaft hole; the center of the twelfth magnetic barrier arc is the fifth center; is the radial distance from the midpoint of the inner arc of the through hole to the edge of the rotor pressure plate;

[0024] The ninth magnetic barrier arc and the tenth magnetic barrier arc are symmetrically distributed about a target symmetry axis; the target symmetry axis is the symmetry axis of the permanent magnets that the two second magnetic barriers are facing respectively.

[0025] Optionally, c1 and c3 both meet the minimum distances required for the rotor mechanical strength of the motor.

[0026] Optionally, the target angle θ satisfies the following conditions: 0<θ<2π and θ≠k*π / p, k=1, 2, ... 2p-1, p is the number of pole pairs of the motor;

[0027] And / or, the material of the pressing plate body is silicon steel sheet;

[0028] And / or, a magnetic barrier is provided on the rotor core in an area opposite to the rotor pressure plate.

[0029] In a second aspect, a permanent magnet synchronous motor is provided, the permanent magnet synchronous motor comprising a rotor, the rotor comprising the rotor pressure plate described in any one of the first aspects.

[0030] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present disclosure.

[0031] The positive and progressive effect of the present disclosure is that: in the present disclosure, the pressure plate body can be made of any material with a magnetic permeability greater than the magnetic permeability threshold, and a special process is required to manufacture the stainless steel pressure plate, which can save manufacturing costs and material costs. In order to avoid the use of a pressure plate body with a higher magnetic permeability causing the leakage of magnetic flux at the rotor end of the motor to become serious, in this embodiment, the pressure plate body and the rotor core are overlapped by a target angle in the axial direction, and a magnetic barrier is set in the leakage area of ​​the pressure plate body, so as to effectively reduce the leakage of magnetic flux at the rotor end, avoid a significant drop in back electromotive force, and ensure the torque output of the motor under the same current excitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic cross-sectional view of a rotor core provided by an exemplary embodiment of the present disclosure;

[0033] Figure 2 A schematic cross-sectional view of a rotor pressure plate provided by an exemplary embodiment of the present disclosure;

[0034] Figure 3 A schematic diagram of a partial structure of a rotor pressure plate and a rotor core after being axially overlapped by a target angle provided by an exemplary embodiment of the present disclosure;

[0035] Figure 4 A schematic diagram of the effect of magnetic field distribution of a rotor pressure plate without magnetic barriers provided by an exemplary embodiment of the present disclosure;

[0036] Figure 5 A schematic diagram of the size relationship of a magnetic barrier of a rotor pressure plate provided by an exemplary embodiment of the present disclosure;

[0037] Figure 6 A schematic diagram of the effect of magnetic field distribution of a rotor pressure plate with a magnetic barrier provided in a magnetic flux leakage area L1 provided by an exemplary embodiment of the present disclosure;

[0038] Figure 7 A schematic structural diagram of another magnetic barrier of a rotor pressure plate provided by an exemplary embodiment of the present disclosure;

[0039] Figure 8 A schematic diagram of the size relationship of a magnetic barrier of another rotor pressure plate provided by an exemplary embodiment of the present disclosure;

[0040] Fig. 9 A schematic diagram of the effect of magnetic field distribution of a rotor pressure plate with a magnetic barrier provided in a magnetic flux leakage area L2 provided by an exemplary embodiment of the present disclosure;

[0041] Fig.10 A schematic structural diagram of a motor including a rotor pressure plate in which magnetic barriers are provided in both the magnetic leakage region L1 and the magnetic leakage region L2, provided by an exemplary embodiment of the present disclosure;

[0042] Fig.11 An exemplary embodiment of the present disclosure provides a Fig. 9 A comparative schematic diagram of the no-load back electromotive force of the motor shown, the motor including the rotor pressure plate without magnetic barriers, and the motor including the rotor pressure plate of stainless steel;

[0043] Fig.12 A schematic structural diagram of a motor including a rotor pressure plate without a magnetic barrier provided by an exemplary embodiment of the present disclosure;

[0044] Fig.13 A schematic structural diagram of a motor including a rotor pressure plate with a magnetic barrier provided in an exemplary embodiment of the present disclosure;

[0045] Fig.14 A schematic diagram of the size relationship of a magnetic barrier of another rotor pressure plate provided by an exemplary embodiment of the present disclosure;

[0046] Fig.15 A schematic diagram of the dimensional relationship of a magnetic barrier of another rotor pressure plate provided as an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0047] The present disclosure is further described below by way of examples, but the present disclosure is not limited to the scope of the examples.

[0048] Prefixes such as "first" and "second" are used in the embodiments of the present disclosure only to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers to distinguish description objects in the embodiments of the present disclosure does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and no unnecessary limitation should be constituted due to the use of such prefixes. In addition, in the description of the present embodiment, unless otherwise specified, the meaning of "plurality" is two or more.

[0049] The present disclosure provides a rotor pressure plate, which is applied to a motor. The motor includes a rotor core in addition to the rotor pressure plate. Figure 1 , at least two magnetic steel slots are provided on the rotor core 11, each of which contains a permanent magnet 12, and the polarities of two adjacent permanent magnets are opposite. In the figure, the blue permanent magnet is N polarity, and the red permanent magnet is S polarity.

[0050] The rotor pressure plate body in this embodiment is made of a material having a magnetic permeability greater than a magnetic permeability threshold, see Figure 2 and Figure 3 The pressure plate body 21 is provided with through holes 22 corresponding to each permanent magnet, and the pressure plate body and the rotor core are overlapped by a target angle in the axial direction, so that a part of the area of ​​each permanent magnet overlaps with the pressure plate body, that is, a part of the area of ​​the permanent magnet is blocked by the pressure plate body. A magnetic barrier 23 is provided in the leakage magnetic region of the pressure plate body, which can block the leakage magnetic flux path of the permanent magnet through the rotor pressure plate, thereby suppressing the leakage magnetic flux of the rotor pressure plate.

[0051] The magnetic permeability is greater than the magnetic permeability threshold, that is, the higher magnetic permeability. The magnetic permeability threshold can be set according to actual needs and will not be described here. The magnetic leakage area can be determined by experiments and simulations.

[0052] In this embodiment, the pressure plate body can be made of any material with a magnetic permeability greater than the magnetic permeability threshold. A special process is required to manufacture the stainless steel pressure plate, which can save manufacturing costs and material costs. In order to avoid the use of a pressure plate body with a higher magnetic permeability, which causes the leakage of magnetic flux at the rotor end of the motor to become serious, in this embodiment, the pressure plate body and the rotor core are overlapped by a target angle in the axial direction, and a magnetic barrier is set in the leakage area of ​​the pressure plate body, so as to effectively reduce the leakage of magnetic flux at the rotor end, avoid a significant drop in back electromotive force, and ensure the torque output of the motor under the same current excitation.

[0053] In one embodiment, the pressure plate body is further provided with an axial hole 24 and a rivet hole 25. The pressure plate body is installed on the rotating shaft of the rotor core through the axial hole 24 and is fixed to the end of the rotor core through the rivet hole 25, thereby playing a role in fixing the permanent magnet in the axial direction, thereby realizing the assembly of the pressure plate body.

[0054] In one embodiment, the same magnetic barrier is arranged on the rotor core in the area opposite to the rotor pressure plate, so as to further improve the effectiveness of suppressing magnetic leakage of the rotor pressure plate.

[0055] The shape of the magnetic barrier can be circular, rectangular, trapezoidal, etc. In order to achieve the best effect of suppressing the leakage of the rotor pressure plate, the optimal magnetic barrier shape is determined according to the axial overlapping area of ​​the permanent magnet and the rotor pressure plate and / or the shape of the permanent magnet.

[0056] When no magnetic barrier is set, the magnetic field of the rotor pressure plate is as follows: Figure 4 As shown, due to the high magnetic permeability of the rotor pressure plate, the motor has obvious magnetic leakage, namely, magnetic leakage area L1 and magnetic leakage area L2. For magnetic leakage area L1, its magnetic leakage flux path is permanent magnet N pole-rotor core-rotor pressure plate-rotor core-permanent magnet S pole-permanent magnet N pole. For magnetic leakage area L2, its magnetic leakage flux path is N pole permanent magnet-rotor core-rotor pressure plate-rotor core-S pole permanent magnet-rotor core-N pole permanent magnet and N pole permanent magnet-rotor pressure plate-S pole permanent magnet-rotor core-N pole permanent magnet.

[0057] In one embodiment, the magnetic leakage area includes: a first sub-area located between two adjacent through holes and facing the permanent magnet, that is, Figure 4 The shape of the first magnetic barrier in the first sub-region L1 is determined according to the shape of the permanent magnet facing the first sub-region.

[0058] The first magnetic barrier can suppress the leakage flux of a single permanent magnet through the rotor pressure plate, and the leakage flux path is the N pole of the single permanent magnet-rotor core-rotor pressure plate-rotor core-S pole of the single permanent magnet-N pole of the single permanent magnet.

[0059] In one embodiment, see Figure 3 and Figure 5 The shape of the first magnetic barrier is determined according to the first magnetic barrier arc l1, the second magnetic barrier arc l2, the third magnetic barrier arc l3 and the fourth magnetic barrier arc l4 which are connected end to end in sequence. The first magnetic barrier arc, the second magnetic barrier arc, the third magnetic barrier arc and the fourth magnetic barrier arc have the following constraint relationship:

[0060] ; ; ;

[0061] Wherein, R1, R2, R3 and R4 are respectively the radii of the first inner arc, the first outer arc, the first magnetic barrier arc l1 and the second magnetic barrier arc l2 of the first permanent magnet directly opposite to the first magnetic barrier, and the centers of the first inner arc, the first outer arc, the first magnetic barrier arc l1 and the second magnetic barrier arc l2 are all the first center O1; a1 is the minimum distance from the first inner arc to the first magnetic barrier arc l1, a2 is the minimum distance from the first magnetic barrier arc l1 to the second magnetic barrier arc l2, and a3 is the minimum distance from the first outer arc to the second magnetic barrier arc l2; h m is the thickness of the permanent magnet; R5 and R6 are respectively the radii of the second outer arc of the through hole close to the third magnetic barrier arc and the third magnetic barrier arc l3, and the centers of the second outer arc and the third magnetic barrier arc are both the second center O2; b1 is the minimum distance from the second outer arc to the third magnetic barrier arc l3; R7 and R8 are respectively the radius of the third outer arc of the through hole close to the fourth magnetic barrier arc l4 and the radius of the fourth magnetic barrier arc l4, and the centers of the fourth magnetic barrier arc l4 and the third outer arc are both the third center O3; b2 is the minimum distance from the third outer arc to the fourth magnetic barrier arc l4.

[0062] Since the leakage flux mainly occurs in the magnetic steel width h m So set the constraint relationship In other implementations, you can also set Setting the constraint relationships b1>0 and b2>0 can ensure that the entire rotor pressure plate is connected and has a certain structural strength, thereby preventing deformation caused by centrifugal force after the rotor rotates.

[0063] Figure 3 , Figure 5 The structure of the rotor pressure plate is explained by taking the example of the rotor pressure plate rotating 90° (target angle) counterclockwise relative to the rotor core axis. In actual applications, the target angle can be set according to actual needs.

[0064] In one embodiment, the distances from the first center O1, the second center O2 and the third center O3 to the center O of the axial hole are equal.

[0065] If the distances from the center of each arc to the center of the shaft hole are different, there will be a problem of asymmetric stress on b1 and b2, which may easily cause deformation of the rotor pressure plate. In this embodiment, the distances from the center of each arc to the center of the shaft hole are set to be the same, so that the widths of b1 and b2 are the same, which is conducive to b1 and b2 evenly dividing the stress after the rotor rotates, thereby reducing or even avoiding deformation of the rotor pressure plate.

[0066] In one embodiment, ∠O1OO2=30°; and / or, ∠O1OO3=30°. The above angles can be determined according to 360° / number of poles / 2, and the two angles are set equal to make the left and right magnetic barriers symmetrical.

[0067] It should be noted that the values ​​of b1, b2, a1, a3, and a2 cannot be too small and need to meet the mechanical strength requirements of the rotor. In one embodiment, b1, b2, a1, a3, and a2 all meet the minimum distance of the mechanical strength of the rotor of the motor.

[0068] See also Figure 6 , the figure shows the magnetic field distribution of the rotor pressure plate using the first magnetic barrier when the number of stator slots of the motor is 9, the number of poles of the permanent magnet is 6, the shape of the permanent magnet is crescent-shaped, the number of rivets is 4, the rotor pressure plate is rotated 90° (target angle) counterclockwise relative to the rotor core axis, and b1=b2=0.5mm, a1=a3=0.5mm, a2=4mm. It can be seen that the leakage flux in the leakage flux area L1 is significantly suppressed.

[0069] In one embodiment, the magnetic flux leakage area includes: a second sub-area located on one side of the inner arc of the through hole and facing the permanent magnet, that is, Figure 7 The area L2 facing the permanent magnet in the middle leakage magnetic area 21 The shape of the second magnetic barrier in the second sub-region is determined according to the shape of the permanent magnet facing the second sub-region.

[0070] The second magnetic barrier can suppress the leakage flux of a single permanent magnet through the rotor pressure plate, and the leakage flux path is the N pole of the single permanent magnet-rotor core-rotor pressure plate-rotor core-S pole of the single permanent magnet-N pole of the single permanent magnet.

[0071] In one embodiment, see Figure 7 , Figure 8 The shape of the second magnetic barrier located in the second sub-area is determined according to the fifth magnetic barrier arc l5, the sixth magnetic barrier arc l6, the seventh magnetic barrier arc l7 and the eighth magnetic barrier arc l8 which are connected end to end in sequence; the fifth magnetic barrier arc l5, the sixth magnetic barrier arc l6, the seventh magnetic barrier arc l7 and the eighth magnetic barrier arc l8 have the following constraint relationship:

[0072] ; ; ;

[0073] Among them, R9, R 10 , R 11 and R 12 are respectively the radii of the second inner arc, the fourth outer arc, the fifth magnetic barrier arc l5 and the sixth magnetic barrier arc l6 of the permanent magnet directly facing the second magnetic barrier, and the centers of the second inner arc, the fourth outer arc, the fifth magnetic barrier arc l5 and the sixth magnetic barrier arc l6 are all the fourth center O4; d1 is the minimum distance from the second inner arc to the fifth magnetic barrier arc, d2 is the minimum distance from the fifth magnetic barrier arc l5 to the sixth magnetic barrier arc l6, and d3 is the minimum distance from the fourth outer arc to the sixth magnetic barrier arc l6; h mis the thickness of the permanent magnet; R 14 , R ro are the radius of the seventh magnetic barrier arc l7 and the outer diameter of the rotor core respectively. The rotor core and the seventh magnetic barrier arc l7 are co-centered with the hole axis O; c1 is the minimum distance from the outer edge of the rotor core to the seventh magnetic barrier arc l7; R 16 R is the radius of the third inner arc of the through hole close to the eighth magnetic barrier arc, 17 is the radius of the eighth magnetic barrier arc l8, the centers of the eighth magnetic barrier arc l8 and the third inner arc are both the fifth center O5; c3 is the minimum distance from the third inner arc to the eighth magnetic barrier arc l8.

[0074] Since the leakage flux mainly occurs in the magnetic steel width h m So set the constraint relationship In other implementations, you can also set Setting the constraint relations c1>0 and c3>0 can ensure that the entire rotor pressure plate is connected and has a certain structural strength, thereby preventing deformation caused by centrifugal force after the rotor rotates.

[0075] In one embodiment, the second sub-region includes two second magnetic barriers, and the two second magnetic barriers are symmetrically distributed about the target symmetry axis; the target symmetry axis is the symmetry axis of the permanent magnets that the two second magnetic barriers are facing respectively. Figure 7 The fifth magnetic barrier arc l9 and the sixth magnetic barrier arc l 10 , the seventh magnetic barrier arc l 11 and the eighth magnetic barrier arc l 12 The magnetic barrier formed is another symmetrical magnetic barrier. The parameters and constraint relationships of the two second magnetic barriers in the second sub-area are the same, except that the centers of the circles are different. The fifth magnetic barrier arc l9 and the sixth magnetic barrier arc l 10 The center of the circle is O6.

[0076] In one embodiment, the magnetic flux leakage area includes: a third sub-area located on one side of the inner arc of the through hole and facing the area between the two permanent magnets, that is, Figure 7 The area L2 of the magnetic leakage area not facing the permanent magnet 22 .

[0077] The third magnetic barrier in the third sub-region can suppress the leakage flux of adjacent permanent magnets through the rotor pressure plate, and the leakage flux path is N-pole permanent magnet-rotor core-rotor pressure plate-rotor core-S-pole permanent magnet-rotor core-N-pole permanent magnet and N-pole permanent magnet-rotor pressure plate-S-pole permanent magnet-rotor core-N-pole permanent magnet.

[0078] In one embodiment, the shape of the third magnetic barrier is based on the ninth magnetic barrier arc l connected end to end. 13 、The tenth magnetic barrier arc l 14 、The eleventh magnetic barrier arc l15 and the twelfth magnetic barrier arc l 16 Confirm; the ninth magnetic barrier arc l 13 、The tenth magnetic barrier arc l 14 、The eleventh magnetic barrier arc l 15 and the twelfth magnetic barrier arc l 16 It has the following constraints:

[0079] ;

[0080] Among them, R 13 is the ninth magnetic barrier arc l 13 The radius of the ninth magnetic barrier arc l 13 The center of the circle is the fourth center; g1 is the ninth magnetic barrier arc l 13 Minimum distance to the fourth outer arc; is the eleventh magnetic barrier arc l 15 To the twelfth magnetic barrier arc l 16 The minimum distance of the eleventh magnetic barrier arc l 15 The same center as the shaft hole; the twelfth magnetic barrier arc l 16 The center of each circle is the fifth circle center O5. It is the radial distance from the midpoint of the inner arc of the through hole to the edge of the rotor pressure plate.

[0081] The ninth magnetic barrier arc l 13 The tenth magnetic barrier arc l 14 The target symmetry axis is symmetrically distributed; the target symmetry axis is the symmetry axis of the permanent magnets that the two second magnetic barriers are facing.

[0082] In one embodiment, the fourth circle center O4 and the fifth circle center O5 are at the same distance from the center of the shaft hole O. In this embodiment, setting the center of each arc to the center of the shaft hole at the same distance is conducive to evenly distributing the stress after the rotor rotates, thereby reducing or even avoiding deformation of the rotor pressure plate.

[0083] In one embodiment, ∠O4OO5=30°; and / or, ∠O5OO6=30°. The above angles can be determined according to 360° / number of poles / 2, and the two angles are set equal to make the left and right magnetic barriers symmetrical.

[0084] It should be noted that the values ​​of c1 and c3 cannot be too small and need to meet the mechanical strength requirements of the rotor. In one embodiment, c1 and c3 both meet the minimum distance of the mechanical strength of the rotor of the motor.

[0085] See also Fig. 9, the figure shows the magnetic field distribution of the rotor pressure plate with the second and third magnetic barriers when the number of stator slots of the motor is 9, the number of poles of the permanent magnet is 6, the shape of the permanent magnet is crescent-shaped, the number of rivets is 4, the rotor pressure plate is rotated 90° (target angle) counterclockwise relative to the rotor core axis, and d1=d3=0.5mm, d2=4mm, c1=c3=0.6mm, c2=7.5mm, g1=0.2mm. It can be seen that the leakage flux in the leakage flux area L2 is significantly suppressed.

[0086] In one embodiment, the magnetic flux leakage region includes at least two of the first sub-region, the second sub-region, and the third sub-region.

[0087] Fig.10 A schematic diagram of a motor structure is shown, in which the motor includes a rotor pressure plate that opens magnetic barriers in the leakage magnetic areas L1 and L2 at the same time, and suppresses the leakage magnetic field in the leakage magnetic areas L1 and L2, and the magnetic barrier parameters are b1=b2=0.6mm, a1=a3=0.5mm, a2=4mm, d1=d3=0.5mm, d2=4mm, c1=c3=0.6mm, c2=7.5mm, and g1=0.2mm. Fig.11 The comparison of the no-load back EMF of the motor under different schemes is shown in the figure. When the rotor pressure plate with magnetic barrier is adopted in this embodiment, the effective value of the no-load back EMF of the motor is 54 V when the motor speed is 1500 rpm. Compared with the rotor pressure plate without magnetic barrier, the effective value of the no-load back EMF of the motor is increased by 9.53%; compared with the stainless steel rotor pressure plate, the effective value of the no-load back EMF of the motor is reduced by 3.57%.

[0088] In one embodiment, when the rotor pressure plate and the rotor core are axially overlapped by an angle, if the magnetic isolation bridge of the rotor pressure plate coincides with the magnetic isolation bridge of the rotor core in the axial direction, then the magnetic isolation bridge of the rotor pressure plate can act as a third magnetic barrier. At this time, the rotor pressure plate can open the first magnetic barrier and / or the second magnetic barrier to suppress the leakage flux path of a single permanent magnet.

[0089] In one embodiment, the material of the pressure plate body is silicon steel sheet. Preferably, the silicon steel sheet of the rotor core is used as the pressure plate body, and the rotor core and the pressure plate body have exactly the same shape and size. This solution can save the mold cost of the rotor pressure plate, thereby further reducing the cost of the motor.

[0090] It should be noted that the number of layers of silicon steel sheets contained in the pressure plate body can be set according to actual needs. When multiple layers of silicon steel sheets are used, the magnetic barrier has a corresponding multi-layer structure, which can control the distribution of magnetic flux without affecting the direction of magnetic lines of force of other axes, thereby improving the performance of the motor.

[0091] In one embodiment, the target angle θ satisfies the following conditions: 0<θ<2π and θ≠k*π / p, k=1, 2, ... 2p-1, and p is the number of pole pairs of the motor.

[0092] It should be noted that when the target angle is different, the overlapping area between the rotor pressure plate and the permanent magnet in the axial direction is also different, and the shape and size of the magnetic barrier also change, but the shape and size of the magnetic barrier can still be designed according to the magnetic barrier constraint conditions provided in the above embodiment.

[0093] When the rotor pressure plate is rotated 72.5° (target angle) counterclockwise relative to the rotor core axis, the motor including the rotor pressure plate structure without magnetic barriers is Fig.12 In order to suppress the magnetic leakage at the rotor end caused by the rotor pressure plate, the motor including the rotor pressure plate structure with magnetic barriers is as follows Fig.13 shown. Fig.13 The medium magnetic barrier parameters are b1=b2=0.6mm, a1=a3=1mm, a2=3mm, d1=d3=1mm, d2=3mm, c1=c3=0.6mm, c2=7.5mm.

[0094] Fig.13 In the figure, magnetic barrier A is used to suppress the leakage flux of the single permanent magnet through the rotor pressure plate on the right side, and magnetic barrier B is used to suppress the leakage flux of the single permanent magnet through the rotor pressure plate on the left side. Since the rotor pressure plate rotates 72.5° counterclockwise relative to the rotor core axis, the rotor pressure plate magnetic isolation bridge and the rotor core magnetic isolation bridge overlap in the axial direction, and the third magnetic barrier can be omitted. In addition, since the magnetic steel slot of the rotor pressure plate corresponds to the right part of the single permanent magnet in the axial direction, the magnetic barrier symmetrical to magnetic barrier A can also be omitted.

[0095] Taking the magnetic barrier above the y-axis as an example, the geometric parameters of the magnetic barrier B are as follows: Fig.14 As shown, the constraints are as follows:

[0096] ; ; ;

[0097] Among them, R1, R2, R3 and R4 are respectively the inner arc of the permanent magnet, the outer arc of the permanent magnet, and the arc l 17 and arc l 18 The radius of their circles is O1. a1 is the radius of the arc inside the permanent magnet to the arc l 17 The minimum distance, a2 is the arc l 17 To arc l 18 The minimum distance between the arc outside the permanent magnet and the arc l 18 R5 and R6 are the arc outside the magnetic steel slot on the left side of the magnetic barrier and the arc l 19The radius of their circles is O2. b1 is the arc from the outer arc of the magnetic steel slot on the left side of the magnetic barrier to the arc l 19 R7 and R8 are the outer arc of the magnetic steel slot on the right side of the magnetic barrier on the rotor pressure plate and the arc l 20 The radius of their circles is O3. b2 is the arc from the outer arc of the magnetic steel slot on the right side of the magnetic barrier to the arc l 20 The minimum distance.

[0098] In addition, the distances from the centers O1, O2 and O3 to the center O are equal. It should be noted that the values ​​of b1 and b2 cannot be too small and need to meet the mechanical strength requirements of the rotor. ∠O1OO2=12.5°, ∠O1OO3=47.5°. It should be noted that this angle is only an example and other angles may be used in other implementations.

[0099] Taking the magnetic barrier above the y-axis as an example, the geometric parameters of the magnetic barrier A are as follows: Fig.15 As shown, the constraints are as follows:

[0100] ; ; ;

[0101] Among them, R 18 , R 19 , R 20 and R 21 They are respectively the arc inside the permanent magnet, the arc outside the permanent magnet, and the arc l 21 and arc l 22 The radius of the circle is O1. d1 is the radius from the inner arc of the permanent magnet to the arc l 21 The minimum distance of the arc l 21 To arc l 22 The minimum distance between the arc outside the permanent magnet and the arc l 22 The minimum distance. R 14 The arc l 23 The radius, R ro is the outer diameter of the rotor, and their centers are both O. c1 is the distance from the outer diameter of the rotor to the arc l 23 The minimum distance. R 16 R is the radius of the arc in the magnetic steel slot. 17 The arc l 24 The radius of their circles is O2. c3 is the radius of the arc in the magnetic steel slot to the arc l 24 The minimum distance.

[0102] use Fig.13The motor with the rotor pressure plate with magnetic barrier is shown. When the motor speed is 1500rpm, the effective value of the motor's no-load back EMF is 54V. Compared with the rotor pressure plate without magnetic barrier, the effective value of the motor's no-load back EMF is increased by 9.53%; compared with the stainless steel rotor pressure plate, the effective value of the motor's no-load back EMF is reduced by 3.57%.

[0103] The embodiment of the present disclosure also provides a permanent magnet synchronous motor, which includes a stator and a rotor, and the rotor includes a rotor pressure plate provided in any of the above embodiments. Specifically, the rotor includes two rotor pressure plates and a rotor core sandwiched between the two rotor pressure plates. The stator includes a stator core and a winding arranged on the stator core.

[0104] Although the specific embodiments of the present disclosure are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present disclosure is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, but these changes and modifications all fall within the protection scope of the present disclosure.

Claims

1. A rotor pressure plate, characterized in that: Applied to a motor, the motor also includes a rotor core, on which at least two permanent magnets are provided; a pressure plate body of the rotor pressure plate is made of a material having a magnetic permeability greater than a magnetic permeability threshold, and a through hole corresponding to each permanent magnet is provided on the pressure plate body, and the pressure plate body and the rotor core are axially staggered at a target angle so that a partial area of ​​each permanent magnet has an overlapping area with the pressure plate body; a magnetic barrier is provided in a leakage magnetic region of the pressure plate body, and the magnetic barrier is used to block the leakage magnetic flux path of the permanent magnet through the rotor pressure plate.

2. The rotor pressure plate according to claim 1, characterized in that: The through hole is in a sector ring shape, and the magnetic leakage area includes: A first sub-region is located between two adjacent through holes; the shape of the magnetic barrier in the first sub-region is determined according to the shape of the permanent magnet facing the first sub-region; and / or, a second sub-region located on one side of the inner arc of the through hole and facing the permanent magnet; the shape of the magnetic barrier in the second sub-region is determined according to the shape of the permanent magnet facing the second sub-region; And / or, a third sub-region located on one side of the inner arc of the through hole and facing the region between the two permanent magnets.

3. The rotor pressure plate according to claim 2, characterized in that: The shape of the first magnetic barrier located in the first sub-region is determined according to a first magnetic barrier arc, a second magnetic barrier arc, a third magnetic barrier arc and a fourth magnetic barrier arc which are connected end to end in sequence, and the first magnetic barrier arc, the second magnetic barrier arc, the third magnetic barrier arc and the fourth magnetic barrier arc have the following constraint relationship: ； ； ； Wherein, R1, R2, R3 and R4 are respectively the radii of the first inner arc, the first outer arc, the first magnetic barrier arc and the second magnetic barrier arc of the first permanent magnet directly opposite to the first magnetic barrier, and the centers of the first inner arc, the first outer arc, the first magnetic barrier arc and the second magnetic barrier arc are all the first center; a1 is the minimum distance from the first inner arc to the first magnetic barrier arc, a2 is the minimum distance from the first magnetic barrier arc to the second magnetic barrier arc, and a3 is the minimum distance from the first outer arc to the second magnetic barrier arc; h m is the thickness of the permanent magnet; R5 and R6 are respectively the radius of the second outer arc of the through hole close to the third magnetic barrier arc and the radius of the third magnetic barrier arc, and the centers of the second outer arc and the third magnetic barrier arc are both the second center; b1 is the minimum distance from the second outer arc to the third magnetic barrier arc; R7 and R8 are respectively the radius of the third outer arc of the through hole close to the fourth magnetic barrier arc and the radius of the fourth magnetic barrier arc, and the centers of the fourth magnetic barrier arc and the third outer arc are both the third center; b2 is the minimum distance from the third outer arc to the fourth magnetic barrier arc.

4. The rotor pressure plate according to claim 3, characterized in that: The center of the pressing plate body is also provided with an axial hole; the angle formed by the center of the axial hole, the first center of the circle, and the second center of the circle is 30°; and / or the angle formed by the center of the axial hole, the first center of the circle, and the third center of the circle is 30°; And / or, b1, b2, a1, a3, a2 all meet the minimum distances required for the mechanical strength of the rotor of the motor.

5. The rotor pressure plate according to claim 2, characterized in that: The center of the pressing plate body is also provided with an axial hole; the shape of the second magnetic barrier located in the second sub-area is determined according to the fifth magnetic barrier arc, the sixth magnetic barrier arc, the seventh magnetic barrier arc and the eighth magnetic barrier arc which are connected end to end in sequence; the fifth magnetic barrier arc, the sixth magnetic barrier arc, the seventh magnetic barrier arc and the eighth magnetic barrier arc have the following constraint relationship: ； ； ； Among them, R9, R 10 , R 11 and R 12 are respectively the radii of the second inner arc, the fourth outer arc, the fifth magnetic barrier arc and the sixth magnetic barrier arc of the permanent magnet directly facing the second magnetic barrier, and the centers of the second inner arc, the fourth outer arc, the fifth magnetic barrier arc and the sixth magnetic barrier arc are all the fourth center; d1 is the minimum distance from the second inner arc to the fifth magnetic barrier arc, d2 is the minimum distance from the fifth magnetic barrier arc to the sixth magnetic barrier arc, and d3 is the minimum distance from the fourth outer arc to the sixth magnetic barrier arc; h m is the thickness of the permanent magnet; R 14 , R ro are the radius of the seventh magnetic barrier arc and the outer diameter of the rotor core respectively. The rotor core and the seventh magnetic barrier arc are cocentric with the hole axis of the rotor pressure plate; c1 is the minimum distance from the outer edge of the rotor core to the seventh magnetic barrier arc; R 16 is the radius of the third inner arc of the through hole close to the eighth magnetic barrier arc, R 17 is the radius of the eighth magnetic barrier arc, the centers of the eighth magnetic barrier arc and the third inner arc are both the fifth center; c3 is the minimum distance from the third inner arc to the eighth magnetic barrier arc.

6. The rotor pressure plate according to claim 5, characterized in that: The second sub-region includes two second magnetic barriers, which are symmetrically distributed about a target symmetry axis; the target symmetry axis is a symmetry axis of a permanent magnet that the two second magnetic barriers are facing respectively; and / or, the distances from the fourth circle center and the fifth circle center to the center of the shaft hole are equal; And / or, the angle formed by the center of the axial hole and the fourth center and the fifth center is 30°.

7. The rotor pressure plate according to claim 5, characterized in that: The shape of the third magnetic barrier of the third sub-region is determined according to the ninth magnetic barrier arc, the tenth magnetic barrier arc, the eleventh magnetic barrier arc and the twelfth magnetic barrier arc which are connected end to end in sequence; the ninth magnetic barrier arc, the tenth magnetic barrier arc, the eleventh magnetic barrier arc and the twelfth magnetic barrier arc have the following constraint relationship: ； Among them, R 13 is the radius of the ninth magnetic barrier arc, the center of the ninth magnetic barrier arc is the fourth center; g1 is the minimum distance from the ninth magnetic barrier arc to the fourth outer arc; is the minimum distance from the eleventh magnetic barrier arc to the twelfth magnetic barrier arc; the eleventh magnetic barrier arc is concentric with the shaft hole; the center of the twelfth magnetic barrier arc is the fifth center; is the radial distance from the midpoint of the inner arc of the through hole to the edge of the rotor pressure plate; The ninth magnetic barrier arc and the tenth magnetic barrier arc are symmetrically distributed about a target symmetry axis; the target symmetry axis is the symmetry axis of the permanent magnets that the two second magnetic barriers are facing respectively.

8. The rotor pressure plate according to claim 7, characterized in that: Both c1 and c3 are minimum distances that meet the mechanical strength requirements of the motor's rotor.

9. The rotor pressure plate according to any one of claims 1 to 8, characterized in that: The target angle θ satisfies the following conditions: 0<θ<2π and θ≠k*π / p, k=1, 2, ... 2p-1, p is the number of pole pairs of the motor; And / or, the material of the pressing plate body is silicon steel sheet; And / or, a magnetic barrier is provided on the rotor core in an area opposite to the rotor pressure plate.

10. A permanent magnet synchronous motor, characterized in that: The permanent magnet synchronous motor comprises a rotor, and the rotor comprises a rotor pressure plate according to any one of claims 1-9.

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