A permanent magnet synchronous motor with radial double rotor yokeless structure and high torque density

Abstract

The present invention discloses a permanent magnet synchronous motor with a radial double rotor yokeless structure and high torque density, wherein a permanent magnet sheath is sleeved on the inner permanent magnet, and a hollow shaft is installed on the annular boss of the bracket bottom plate; an oil separator sleeve is sleeved on each stator core and stator bracket, and fixedly connected to the inner end face of the end cover; the oil separator sleeve, the stator core and the stator bracket are inserted between the annular cavity formed by the inner permanent magnet and the outer permanent magnet, and an annular mounting seat is provided in the middle of the inner end face of the end cover, which is sleeved on the outside of the hollow shaft of the rotor assembly through the annular mounting seat, and the hollow shaft and the annular mounting seat are connected and supported by a double-row deep groove ball bearing; a rotary transformer and a rotary transformer stator bracket are sleeved on the outer side of the transmission end of the hollow shaft in sequence, and the rotor of the rotary transformer is fixedly sleeved on the hollow shaft, and its stator sleeve is sleeved on the outside of its rotor. The present invention solves the problems of complex mechanical layout, low efficiency and torque density indicators, and poor cooling methods of the existing radial double rotor yokeless motor.

Description

Technical Field

[0001] The present invention relates to the field of motor technology, but is not limited to it, and in particular to a permanent magnet synchronous motor with a radial double-rotor yokeless structure and high torque density. Background Art

[0002] As permanent magnet synchronous motor technology continues to mature, its application scope in the fields of aviation, automobiles, etc. is gradually expanding. This type of motor usually needs to have characteristics such as light weight, high torque density, and high efficiency. The dual rotor and yokeless structure design of the motor can simplify the magnetic circuit to a certain extent, which has a significant effect on improving power density.

[0003] Among the existing permanent magnet synchronous motor structures, one type is a dual-rotor yokeless motor, which is mostly an axial flux motor. This type of motor has a problem, that is, there is a large axial magnetic pull between the stator and the rotor. When the motor power and radial size are large, the rotor is easily bent by the axial magnetic pull, resulting in assembly difficulties. In addition, in large-diameter axial flux motors, the air gap between the stator and the rotor is very small. After being subjected to large bumps or vibrations, if there is a slight deflection, it may cause the hidden danger of stator and rotor friction.

[0004] The other type uses a radial twin-rotor yokeless motor. Although it avoids the shortcomings of the axial twin-rotor yokeless motor, due to deficiencies in the structural design, it cannot achieve satisfactory results in terms of efficiency, torque density index, structural simplicity and cooling method. Summary of the invention

[0005] Purpose of the invention: In order to solve the above-mentioned technical problems, an embodiment of the present invention provides a permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density, so as to solve the problems of the existing radial dual-rotor yokeless motor with complex mechanical layout, low efficiency and torque density indicators, and poor cooling method.

[0006] The technical solution of the present invention: The embodiment of the present invention provides a permanent magnet synchronous motor with a radial double rotor yokeless structure and high torque density, comprising: a rotor assembly 1, a stator assembly 2, a rotary transformer 3, an elastic retaining ring 4, a rotary transformer stator bracket 5, a double-row deep groove ball bearing 6 and an oil separator 13;

[0007] The rotor assembly 1 comprises: a rotor support 101, an inner permanent magnet 102, an outer permanent magnet 103, a permanent magnet sleeve 104, and a hollow shaft 105; the rotor support 101 comprises a disc-shaped support base plate, and an outer ring support arm sleeve and an inner ring support arm sleeve located on the inner end surface of the support base plate, wherein the outer ring support arm sleeve and the inner ring support arm sleeve form an annular cavity with an opening; the outer permanent magnet 103 is pasted on the inner wall surface of the outer ring support arm sleeve, the inner permanent magnet 102 is pasted on the outer wall surface of the inner ring support arm sleeve, the permanent magnet sleeve 104 is sleeved on the outside of the inner permanent magnet 102 by interference fit, and the middle part of the support base plate has an annular boss for sleeve-mounting the hollow shaft 105;

[0008] The stator assembly 2 includes: an end cover 201, a stator core 202, and a stator bracket 203; a plurality of stator brackets 203 are evenly fixedly installed on the inner end surface of the end cover 201 along the circumferential direction, forming an annular bracket structure as a whole; each stator core 202 is nested and installed between adjacent stator brackets 203 along the circumferential direction; the oil separator sleeve 13 is set as an annular spacer structure with one end open, and the oil separator sleeve 13 is integrally sleeved on each stator core 202 and the stator bracket 203, and is fixedly connected to the inner end surface of the end cover 201; and the stator core 202, and the assembly structure of the oil separator sleeve 13, the adjacent stator core 202 and the stator bracket 203 are integrally inserted between the annular cavity formed by the inner permanent magnet 102 and the outer permanent magnet 103;

[0009] An annular mounting seat is provided in the middle of the inner end surface of the end cover 201 of the stator assembly 2, which is sleeved on the outside of the hollow shaft 105 of the rotor assembly 1, and the hollow shaft 105 and the annular mounting seat are connected and supported by a double-row deep groove ball bearing 6;

[0010] The outer side of the transmission end of the hollow shaft 105 is sleeved with a rotary transformer 3 and a rotary transformer stator bracket 5 in sequence. The rotor of the rotary transformer 3 is fixedly sleeved on the hollow shaft 105 and axially positioned. The stator of the rotary transformer 3 is sleeved outside its rotor and axially positioned by the end cover 201 and the rotary transformer stator bracket 5.

[0011] Optionally, in the permanent magnet synchronous motor with radial dual rotor yokeless structure and high torque density as described above, the positioning structure of the stator core 202 in the structure of the stator assembly 2 is:

[0012] The cross section of each stator core 202 is an I-shaped one, and the wedge-shaped grooves formed on the outer and inner sides of two adjacent stator cores 202 are respectively plugged into the wedge-shaped support rods at corresponding positions on the stator bracket 203, so as to position each stator core 202 circumferentially;

[0013] The oil separator 13 is specifically configured as a stepped annular spacer structure with one end open, and the inner diameter of the closed end is smaller than the inner diameter of the stator sleeve. The stator bracket 203 includes a support platform for connecting with the end cover 201 and an outer support rod and an inner support rod for inserting into the outer and inner wedge-shaped grooves of the adjacent stator core 202, and the support platform forms a step portion with the outer support rod and the inner support rod respectively. The stator core 202 is axially positioned by the annular step portion of the oil separator 13 sleeved on the end of each stator core 202 and the support platform on the stator bracket 203.

[0014] Optionally, in the permanent magnet synchronous motor with a radial dual-rotor yokeless structure having a high torque density as described above,

[0015] The oil separator 13 is integrally sleeved on the outside of the stator core 202, and forms an end annular cavity at the end of each stator core 202 through the step area of ​​its closed end, and forms a root annular cavity between the stator core 202 and the stator bracket 203, which serve as two annular oil passages for the cooling medium; through the windings wound on each stator core 202, an axial oil passage is formed in the gap between each winding;

[0016] The two annular oil passages and the axial oil passage are used to cool the windings. The root annular cavity and the end annular cavity are connected via the axial oil passage, and an oil inlet and an oil outlet are provided on the end surface of the end cover 201 .

[0017] Optionally, the permanent magnet synchronous motor with radial dual rotor yokeless structure and high torque density as described above further includes: a bearing sleeve 7, a baffle 8, a sleeve 9, a stop washer 10, and a round nut 11;

[0018] The hollow shaft 105 is configured as a multi-step shaft structure, and an inner shoulder is arranged at its inner end; wherein, the inner end face of the double-row deep groove ball bearing 6 abuts against the inner shoulder, and the hollow shaft 105 is sequentially sleeved with a sleeve 9, a stop washer 10 and a round nut 11 between the double-row deep groove ball bearing 6 and the rotary transformer 3; the inner ring of the double-row deep groove ball bearing 6 is axially positioned by the inner shoulder and the sleeve 9; and the sleeve 9 is axially positioned by the stop washer 10 and the round nut 11 screwed on the hollow shaft 105;

[0019] The bearing sleeve 7 is configured as a sleeve structure with annular retaining rings at both ends, and is integrally sleeved on the outside of the double-row deep groove ball bearing 6, wherein the inner retaining ring abuts against the end of the annular mounting seat in the end cover 201, and the outer retaining ring abuts against the outer end face of the double-row deep groove ball bearing 6. The baffle plate 8 is sleeved with its step ring on the inner retaining ring of the bearing sleeve 7 and the inner end face of the double-row deep groove ball bearing 6, and the bearing outer ring of the double-row deep groove ball bearing 6 is positioned by the bearing sleeve 7 and the baffle plate 8.

[0020] Optionally, the permanent magnet synchronous motor with radial dual rotor yokeless structure and high torque density as described above further includes: an elastic retaining ring 4;

[0021] Between the inner shoulder of the hollow shaft 105 and the transmission end thereof, a middle shoulder and an outer shoulder are sequentially arranged; the outer end of the sleeve 9 extends out of the middle shoulder and is pressed against the outer end of the sleeve 9 by a stop washer 10 and a round nut 11;

[0022] The inner end of the rotor of the rotary transformer 3 abuts against the outer shaft shoulder, and the hollow shaft 105 is also sleeved with an elastic retaining ring 4 on the outer side of the rotor of the rotary transformer 3. The rotor of the rotary transformer 3 is axially positioned by the outer shaft shoulder of the hollow shaft 105 and the elastic retaining ring 4.

[0023] Optionally, the permanent magnet synchronous motor with radial dual rotor yokeless structure and high torque density as described above further includes: a balance ring 12;

[0024] An annular groove is provided on the outer end surface of the bracket base plate of the rotor bracket 101 for embedding and installing the balance ring 12. The balance ring 12 is fixedly connected to the bracket base plate of the rotor bracket 101 by bolts. A plurality of holes are provided on the end surface of the balance ring 12 along the circumferential direction. The dynamic balance of the motor is adjusted by inserting tungsten rods into the holes of the balance ring 12.

[0025] Optionally, in the permanent magnet synchronous motor with a radial dual-rotor yokeless structure with high torque density as described above, an annular flange is formed on the outer end face of the end cover 201 in the stator assembly 2, which is used to install the permanent magnet synchronous motor on an engine or a traction platform, and is fixed to the flanges at both ends by annular clamps.

[0026] Optionally, in the permanent magnet synchronous motor with a radial dual-rotor yokeless structure with high torque density as described above, the inner permanent magnet 102 and the outer permanent magnet 103 in the rotor assembly 1 are respectively divided into two sections in the axial direction, and each section is composed of 320 small permanent magnets on the circumference, for a total of 1280 small permanent magnets.

[0027] Optionally, in the permanent magnet synchronous motor with a radial dual-rotor yokeless structure having a high torque density as described above,

[0028] Each stator core 202 is in an I-shape and is composed of 72 small cores evenly distributed in the circumferential direction.

[0029] Beneficial effects of the present invention: A permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density provided by an embodiment of the present invention has the following beneficial effects:

[0030] First, based on the traditional radial motor structure, it is improved to a yokeless structure (that is, both the stator and the rotor are yokeless). This design not only optimizes the working performance of the motor, but also improves the energy utilization efficiency. Among them, the stator core is yokeless (the stator yoke is removed, and the yokeless segmented stator core is fixed to the front cover through the slot wedge design of the stator bracket), which can eliminate the iron loss of its yoke, reduce the overall loss of the motor to a certain extent, achieve the shortest magnetic flux path and lighter weight, which is conducive to the overall miniaturization of the motor and the improvement of efficiency. The rotor is yokeless (the traditional rotor bracket structure is removed, the rear end cover extends the rotor support arms on the inner and outer sides, and the rotor magnets are glued and fixed) can greatly simplify the mechanical layout, reduce the overall weight of the motor, and improve the power-to-weight ratio and torque density.

[0031] Second, the present invention adopts a dual-rotor structure, in which both the inner and outer rotor support arms are embedded with permanent magnets, and the magnetic field density is effectively improved through the bilateral permanent magnet excitation method, thereby significantly improving the energy density of the motor; in addition, the present invention adopts a single bearing structure (large double-row deep groove ball bearing), which greatly shortens the length of the rotor shaft; while keeping the electromagnetic diameter unchanged, the permanent magnet synchronous motor provided by the present invention can achieve a higher electromagnetic outer diameter to shaft length ratio, which not only improves the overall torque density of the motor, but also enables the motor to have a higher output torque;

[0032] Third, the present invention further improves the overall torque density of the motor through the electromagnetic design of multi-slot, multi-pole, fractional-slot concentrated windings plus multi-segment Halbach array permanent magnets: Among them, the multi-pole, multi-slot design of the permanent magnet synchronous motor stator improves efficiency and torque, reduces vibration and electromagnetic interference, and can better achieve precise control and high power density; the fractional slot design can provide better waveform control characteristics and lower iron loss, which can effectively improve the output performance of the motor and improve the load capacity and stability of the motor; in addition, the yokeless segmented stator core design can reduce the eddy current loss of the core and improve the overall efficiency of the motor. Compared with traditional permanent magnet motors, the motor of the present invention uses a Halbach array to have an air gap magnetic field that is closer to a sinusoidal distribution. Under the condition of the same amount of permanent magnet material, the motor air gap magnetic density is larger, the iron loss is smaller, and the magnetic field is more evenly distributed in the annular path;

[0033] Fourth, compared with traditional air cooling and slotted oil cooling, the stator multi-oil channel oil immersion cooling method adopted by the present invention can reduce winding eddy current loss, improve winding isolation fault tolerance performance, and reduce winding end length while performing efficient cooling.

[0034] To sum up the above analysis, the new type of high torque density radial dual-rotor yokeless permanent magnet synchronous motor provided by the present invention has the characteristics of simple structure, small size (disk-shaped), high torque density, large torque, high efficiency and high fault tolerance. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0036] Figure 1 A cross-sectional view of the overall structure of a permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density provided by an embodiment of the present invention;

[0037] Figure 2 for Figure 1 An axial view of a rotor assembly in a permanent magnet synchronous motor provided by the illustrated embodiment;

[0038] Figure 3 for Figure 1 An axial view of a stator assembly in a permanent magnet synchronous motor provided by the illustrated embodiment;

[0039] Figure 4 for Figure 3 An axial view of a single stator in a permanent magnet synchronous motor provided by the illustrated embodiment;

[0040] Figure 5 for Figure 1 An axial view of a stator support in a permanent magnet synchronous motor provided by the illustrated embodiment;

[0041] Figure 6 for Figure 1 An axial view of an oil separator sleeve in a permanent magnet synchronous motor provided by the illustrated embodiment, FIG.

[0042] Figure 7 for Figure 6 A schematic diagram of the assembly structure of the oil separator sleeve, the stator core and the stator bracket in the permanent magnet synchronous motor provided by the illustrated embodiment;

[0043] Figure 8 A left-axis view of a permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density provided by an embodiment of the present invention;

[0044] Fig. 9 A right axis view of a permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present invention more clear, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0046] The above background technology has already explained that permanent magnet synchronous motors have been widely used in various fields, and there are two structures commonly used in existing permanent magnet synchronous motors, namely, dual-rotor yokeless motors and radial dual-rotor yokeless motors. Among them, dual-rotor yokeless motors are mostly axial flux motors, and there is a large axial magnetic pull between their stators and rotors. The existing radial dual-rotor yokeless motors, because they are only stator-free in structure, still retain a separate rotor bracket structure, and the mechanical layout is relatively complex. In addition, the cooling method of the motor is mostly an oil cooling method or an air cooling method with an external open flow channel. These methods have poor cooling effects and are prone to uneven cooling of the inner and outer sides of the stator core. Therefore, it is also necessary to improve the structure of the relevant motors to improve the motor performance.

[0047] In order to solve the above problems, an embodiment of the present invention provides a permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density. It adopts a permanent magnet dual-rotor yokeless structure (stator yokeless + rotor yokeless) and a multi-slot multi-pole fractional-slot concentrated winding plus a multi-segment Halbach array permanent magnet structure. While greatly simplifying the mechanical structure of the motor, it can have an ultra-high torque density and a high multiple of peak torque.

[0048] The present invention provides the following specific embodiments which can be combined with each other. The same or similar concepts or processes may not be described in detail in some embodiments.

[0049] Figure 1 The overall structural cross-sectional view of a permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density provided by an embodiment of the present invention is shown in FIG. Figure 2 for Figure 1 The embodiment shown provides an axial view of a rotor assembly in a permanent magnet synchronous motor, Figure 3 for Figure 1 The embodiment shown provides an axial view of a stator assembly in a permanent magnet synchronous motor, Figure 4 for Figure 3 The illustrated embodiment provides an axial view of a single stator in a permanent magnet synchronous machine.

[0050] Reference Figures 1 to 4 As shown, the main structure of the permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density provided by an embodiment of the present invention includes: a rotor assembly 1, a stator assembly 2, a rotary transformer 3, an elastic retaining ring 4, a rotary transformer stator bracket 5, a double-row deep groove ball bearing 6 and an oil separator sleeve 13.

[0051] like Figure 1 and Figure 2As shown, the rotor assembly 1 in the embodiment of the present invention includes: a rotor bracket 101, an inner permanent magnet 102, an outer permanent magnet 103, a permanent magnet sleeve 104, and a hollow shaft 105; the rotor bracket 101 includes a disc-shaped bracket base plate, and an outer ring arm sleeve and an inner ring arm sleeve located on the inner end surface of the bracket base plate, and the outer ring arm sleeve and the inner ring arm sleeve form an annular cavity with an opening; the outer permanent magnet 103 is pasted on the inner wall surface of the outer ring arm sleeve, and the inner permanent magnet 102 is pasted on the outer wall surface of the inner ring arm sleeve, and the permanent magnet sleeve 104 is sleeved on the outside of the inner permanent magnet 102 by interference fit, and the middle part of the bracket base plate is provided with an annular boss for sleeve-mounting the hollow shaft 105.

[0052] like Figures 1 to 4 As shown, the stator assembly 2 in the embodiment of the present invention includes: an end cover 201, a stator core 202, and a stator bracket 203; Figure 5 for Figure 1 The embodiment shown is an axial view of a stator support in a permanent magnet synchronous motor; a plurality of stator supports 203 are evenly and fixedly mounted on the inner end surface of the end cover 201 along the circumferential direction, forming an annular support structure as a whole; each stator core 202 is nested and mounted between adjacent stator supports 203 along the circumferential direction. In the embodiment of the present invention, the oil separator 13 is configured as an annular spacer structure with one end open, and the oil separator 13 is integrally mounted on each stator core 202 and the stator support 203, and is fixedly connected to the inner end surface of the end cover 201; and the stator core 202, and the assembly structure of the oil separator 13, the adjacent stator core 202 and the stator support 203 are integrally inserted between the annular cavity formed by the inner permanent magnet 102 and the outer permanent magnet 103.

[0053] In the embodiment of the present invention, an annular mounting seat is provided in the middle of the inner end surface of the end cover 201 of the stator assembly 2, which is sleeved on the outside of the hollow shaft 105 of the rotor assembly 1, and the hollow shaft 105 and the annular mounting seat are connected and supported by a double-row deep groove ball bearing 6.

[0054] The outer side of the transmission end of the hollow shaft 105 is sleeved with a rotary transformer 3 and a rotary transformer stator bracket 5 in sequence. The rotor of the rotary transformer 3 is fixedly sleeved on the hollow shaft 105 and axially positioned. The stator of the rotary transformer 3 is sleeved outside its rotor and axially positioned by the end cover 201 and the rotary transformer stator bracket 5.

[0055] In one implementation of the embodiment of the present invention, Figure 4 As shown, the positioning structure of the stator core 202 in the structure of the stator assembly 2 is as follows: the cross-section of each stator core 202 is an "I" shape, and the wedge-shaped grooves formed on the outer and inner sides of two adjacent stator cores 202 are respectively plugged into the wedge-shaped support rods at the corresponding positions on the stator bracket 203, so as to perform circumferential positioning of each stator core 202.

[0056] Figure 6 for Figure 1 The axial view of the oil separator sleeve in the permanent magnet synchronous motor provided by the embodiment shown, FIG. Figure 7 for Figure 6 Schematic diagram of the assembly structure of the oil separator sleeve, the stator core, and the stator bracket in the permanent magnet synchronous motor provided by the illustrated embodiment. In this implementation, the oil separator sleeve 13 is specifically configured as a stepped annular spacer structure with one end open, and the inner diameter of the closed end is smaller than the inner diameter of the stator sleeve portion. The stator bracket 203 includes a support platform for connecting with the end cover 201 and an outer support rod and an inner support rod for inserting into the outer and inner wedge-shaped grooves of the adjacent stator core 202, and the support platform forms a step portion with the outer support rod and the inner support rod respectively, and the stator core 202 is axially positioned by the annular step portion of the oil separator sleeve 13 sleeved on the end of each stator core 202 and the support platform on the stator bracket 203.

[0057] In this implementation, the oil-isolating sleeve 13 is integrally mounted on the outside of the stator core 202, and forms an end annular cavity at the end of each stator core 202 through the step area at its closed end, and forms a root annular cavity between the stator core 202 and the stator bracket 203, which serve as two annular oil passages for the cooling medium; through the windings wound around each stator core 202, axial oil passages are formed in the gaps between the windings.

[0058] In this implementation, the winding is cooled by two annular oil passages and an axial oil passage, the root annular cavity and the end annular cavity are connected by the axial oil passage, and an oil inlet and an oil outlet are provided on the end surface of the end cover 201.

[0059] In one implementation of the embodiment of the present invention, Figures 1 to 4 As shown, the permanent magnet synchronous motor with a radial double-rotor yokeless structure may further include: a bearing sleeve 7, a baffle 8, a sleeve 9, a stop washer 10, and a round nut 11.

[0060] like Figure 2 As shown, the hollow shaft 105 is configured as a multi-step stepped shaft structure, and an inner shoulder is arranged at its inner end; wherein, the inner end face of the double-row deep groove ball bearing 6 abuts against the inner shoulder, and the hollow shaft 105 is sequentially sleeved with a sleeve 9, a stop washer 10 and a round nut 11 between the double-row deep groove ball bearing 6 and the rotary transformer 3; the inner ring of the double-row deep groove ball bearing 6 is axially positioned by the inner shoulder and the sleeve 9; and the sleeve 9 is axially positioned by the stop washer 10 and the round nut 11 screwed on the hollow shaft 105.

[0061] In this implementation, the bearing sleeve 7 is configured as a sleeve structure with annular retaining rings at both ends, and is integrally sleeved on the outside of the double-row deep groove ball bearing 6, wherein the inner retaining ring thereof abuts against the end of the annular mounting seat in the end cover 201, and the outer retaining ring thereof abuts against the outer end face of the double-row deep groove ball bearing 6, and the baffle plate 8 is sleeved with its step ring on the inner retaining ring of the bearing sleeve 7 and the inner end face of the double-row deep groove ball bearing 6, and the bearing outer ring of the double-row deep groove ball bearing 6 is positioned by the bearing sleeve 7 and the baffle plate 8.

[0062] Furthermore, the permanent magnet synchronous motor with a radial double rotor yokeless structure provided in an embodiment of the present invention may further include: an elastic retaining ring 4.

[0063] Based on the hollow shaft 105 structure provided in the above implementation method, a middle shoulder and an outer shoulder are sequentially arranged between the inner shoulder of the hollow shaft 105 and its transmission end; the outer end of the sleeve 9 extends out of the middle shoulder and is pressed against the outer end of the sleeve 9 by a stop washer 10 and a round nut 11.

[0064] The inner end of the rotor of the rotary transformer 3 abuts against the outer shaft shoulder. The hollow shaft 105 is also sleeved with an elastic retaining ring 4 on the outer side of the rotor of the rotary transformer 3. The rotor of the rotary transformer 3 is axially positioned by the outer shaft shoulder of the hollow shaft 105 and the elastic retaining ring 4.

[0065] In one implementation of the embodiment of the present invention, Figures 1 to 4 As shown, the permanent magnet synchronous motor with a radial double-rotor yokeless structure may further include: a balance ring 12.

[0066] In this implementation, an annular groove is provided on the outer end face of the bracket base plate of the rotor bracket 101 for embedding and installing the balance ring 12. The balance ring 12 is fixedly connected to the bracket base plate of the rotor bracket 101 by bolts. A plurality of holes are provided on the end face of the balance ring 12 along the circumferential direction. The dynamic balance of the motor is adjusted by inserting tungsten rods into the holes of the balance ring 12.

[0067] In a specific implementation, an annular flange is formed on the outer end surface of the end cover 201 in the stator assembly 2, which is used to install the permanent magnet synchronous motor on the engine or the traction platform, and is fixedly mounted on the flanges at both ends through annular clamps.

[0068] In an implementation case of an embodiment of the present invention, Figure 2 As shown, the inner permanent magnet 102 and the outer permanent magnet 103 in the rotor assembly 1 are respectively divided into two sections in the axial direction, and each section is composed of 320 small permanent magnets on the circumference, with a total of 1280 small permanent magnets. In addition, each stator core 202 is in an I-shaped shape and is composed of 72 small cores evenly distributed in the circumferential direction. In addition, the number of poles of the inner permanent magnet and the outer permanent magnet is an even number (the number of magnetic poles is the same), and the polarities of adjacent magnets are opposite.

[0069] The permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density provided by the embodiment of the present invention has the following beneficial effects:

[0070] First, based on the traditional radial motor structure, it is improved to a yokeless structure (that is, both the stator and the rotor are yokeless). This design not only optimizes the working performance of the motor, but also improves the energy utilization efficiency. Among them, the stator core is yokeless (the stator yoke is removed, and the yokeless segmented stator core is fixed to the front cover through the slot wedge design of the stator bracket), which can eliminate the iron loss of its yoke, reduce the overall loss of the motor to a certain extent, achieve the shortest magnetic flux path and lighter weight, which is conducive to the overall miniaturization of the motor and the improvement of efficiency. The rotor is yokeless (the traditional rotor bracket structure is removed, the rear end cover extends the rotor support arms on the inner and outer sides, and the rotor magnets are glued and fixed) can greatly simplify the mechanical layout, reduce the overall weight of the motor, and improve the power-to-weight ratio and torque density.

[0071] Second, the present invention adopts a dual-rotor structure, in which both the inner and outer rotor support arms are embedded with permanent magnets, and the magnetic field density is effectively improved through the bilateral permanent magnet excitation method, thereby significantly improving the energy density of the motor; in addition, the present invention adopts a single bearing structure (large double-row deep groove ball bearing), which greatly shortens the length of the rotor shaft; while keeping the electromagnetic diameter unchanged, the permanent magnet synchronous motor provided by the present invention can achieve a higher electromagnetic outer diameter to shaft length ratio, which not only improves the overall torque density of the motor, but also enables the motor to have a higher output torque;

[0072] Third, the present invention further improves the overall torque density of the motor through the electromagnetic design of multi-slot, multi-pole, fractional-slot concentrated windings plus multi-segment Halbach array permanent magnets: Among them, the multi-pole, multi-slot design of the permanent magnet synchronous motor stator improves efficiency and torque, reduces vibration and electromagnetic interference, and can better achieve precise control and high power density; the fractional slot design can provide better waveform control characteristics and lower iron loss, which can effectively improve the output performance of the motor and improve the load capacity and stability of the motor; in addition, the yokeless segmented stator core design can reduce the eddy current loss of the core and improve the overall efficiency of the motor. Compared with traditional permanent magnet motors, the motor of the present invention uses a Halbach array to have an air gap magnetic field that is closer to a sinusoidal distribution. Under the condition of the same amount of permanent magnet material, the motor air gap magnetic density is larger, the iron loss is smaller, and the magnetic field is more evenly distributed in the annular path;

[0073] Fourth, compared with traditional air cooling and slotted oil cooling, the stator multi-oil channel oil immersion cooling method adopted by the present invention can reduce winding eddy current loss, improve winding isolation fault tolerance performance, and reduce winding end length while performing efficient cooling.

[0074] To sum up the above analysis, the new type of high torque density radial dual-rotor yokeless permanent magnet synchronous motor provided by the present invention has the characteristics of simple structure, small size (disk-shaped), high torque density, large torque, high efficiency and high fault tolerance.

[0075] Figure 8 This is a left-axis view of a permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density provided by an embodiment of the present invention. Fig. 9 A right axis view of a permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density provided by an embodiment of the present invention.

[0076] It should be noted that the end cover 201 and the rotor bracket 101 in the embodiment of the present invention are both made of aluminum alloy; the inner and outer permanent magnets are both made of rare earth neodymium iron boron materials of grade N50UH or above; the stator core 202 can be made of 1J22 soft magnetic alloy; the oil separator sleeve 13 can be made of polyamide plastic; and the permanent magnet sheath is made of carbon fiber material.

[0077] The implementation effect of the permanent magnet synchronous motor with a radial dual-rotor yokeless structure and high torque density provided by the embodiment of the present invention is described below through a specific embodiment:

[0078] Example 1

[0079] like Figure 1 As shown, the high torque density radial dual-rotor yokeless permanent magnet synchronous motor provided in Example 1 includes: a rotor assembly 1, a stator assembly 2, a rotary transformer 3, an elastic retaining ring 4, a rotary transformer stator bracket 5, a double-row deep groove ball bearing 6, a bearing sleeve 7, a baffle 8, a sleeve 9, a stop washer 10, a round nut 11, a balance ring 12, an oil separator 13 and a sealing ring 14.

[0080] The rotor assembly 1 includes: a rotor support 101, an inner permanent magnet 102, an outer permanent magnet 103, a permanent magnet sheath 104, and a hollow shaft 105; the stator assembly 2 includes: an end cover 201, a stator core 202, and a stator support 203. The end cover 201 and the rotor support 101 are both made of aluminum alloy, the inner permanent magnet 102 and the outer permanent magnet 103 on the rotor assembly 1 are both made of rare earth neodymium iron boron materials with a grade of N50UH or above, the stator core 202 is made of 1J22 soft magnetic alloy, the oil separator 13 is made of polyamide plastic, and the permanent magnet sheath 104 is made of carbon fiber material.

[0081] Example 2

[0082] like Figure 1 and Figure 2As shown, the rotor assembly 1 is composed of a rotor support 101, an inner permanent magnet 102, an outer permanent magnet 103, a permanent magnet sheath 104, and a hollow shaft 105, wherein the inner permanent magnet 102 and the outer permanent magnet 103 are each composed of 640 small permanent magnets on the circumference and divided into two sections, with 320 pieces in each section, for a total of 1280 pieces; the inner permanent magnet 102 and the outer permanent magnet 103 are connected to the inner and outer rotor support arms axially extending from the rear end cover 101 by gluing; the inner and outer permanent magnets of the hollow shaft 105 are connected to the inner and outer rotor support arms axially extending from the rear end cover 101 by gluing; The end is flange-shaped, connected to the rear end cover 101 by bolts and stoppers, the outer end is connected to the external rotating device, and the rest is a stepped shaft, connecting the hollow shaft 105 and the annular sleeve of the end cover 201 of the stator assembly 2 through a double-row deep groove ball bearing 6; the permanent magnet sleeve 104 cooperates with the inner permanent magnet 102 by interference fit; the balance ring 12 is connected to the rear end cover 101 by bolts, and the dynamic balance of the motor is adjusted by inserting a tungsten rod into the balance ring 12.

[0083] like Figures 3 to 5 As shown, the stator assembly 2 is composed of an end cover 201, a stator core 202, and a stator bracket 203. Among them, the stator bracket 203 is located inside the housing 15 and is connected and fixed to the front end cover 201 by bolts; the stator core 202 is in an I-shaped shape and is composed of 72 small cores evenly distributed in the circumferential direction. It is mainly positioned circumferentially by cooperating with the stator bracket 203 through the wedge-shaped grooves formed on the outer and inner sides of two adjacent cores, and is positioned axially by the boss of the left oil separator 13 and the support rod of the right stator bracket 203. The stator core 202 is wound with flat wire windings.

[0084] like Figure 1 As shown, a rotary transformer is connected to the inner side of the right end of the hollow shaft 105 , the rotary transformer rotor is axially positioned by the shaft shoulder on the left and the elastic retaining ring 4 on the right, and the rotary transformer stator is axially positioned by the front end cover 201 and the rotary transformer stator bracket 5 .

[0085] Example 3

[0086] like Figures 3 to 6 As shown, the oil inlet and the oil outlet are both located on one side of the end cover 201, and the oil separator 13 is located between the inner permanent magnet 102 and the outer permanent magnet 103, and is connected and fixed to the front end cover 201 by bolts. The oil separator 13 wraps the stator core 202 as a whole, and three oil channels are formed through the inner and outer notches formed by two adjacent small cores and the winding gap for cooling. The sealing ring 14 is embedded in the groove of the stator bracket 203.

[0087] Example 4

[0088] Based on the above three embodiments, when this embodiment is implemented: a high-density current is passed through the flat wire winding in the stator assembly 2 to generate a stator rotating magnetic field. The stator rotating magnetic field interacts with the inner permanent magnet 102 and the outer permanent magnet 103 of the rotor, thereby driving the rear end cover 101 to start rotating. The rear end cover 101 transmits the torque to the hollow shaft 105 through bolts, and the right side of the rotating hollow shaft 105 is connected to an external rotating device, thereby realizing the rotation of the entire system.

[0089] Although the embodiments disclosed in the present invention are as above, the contents are only embodiments adopted to facilitate understanding of the present invention and are not intended to limit the present invention. Any technician in the field to which the present invention belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A permanent magnet synchronous motor with a radial double rotor yokeless structure and high torque density, characterized in that: include: A rotor assembly (1), a stator assembly (2), a rotary transformer (3), an elastic retaining ring (4), a rotary transformer stator bracket (5), a double-row deep groove ball bearing (6) and an oil separator (13); The rotor assembly (1) comprises: a rotor support (101), an inner permanent magnet (102), an outer permanent magnet (103), a permanent magnet sleeve (104), and a hollow shaft (105); the rotor support (101) comprises a disc-shaped support base plate, and an outer ring support arm sleeve and an inner ring support arm sleeve located on the inner side end surface of the support base plate, wherein the outer ring support arm sleeve and the inner ring support arm sleeve form an annular cavity with an opening; the outer permanent magnet (103) is adhered to the inner wall surface of the outer ring support arm sleeve, and the inner permanent magnet (102) is adhered to the outer wall surface of the inner ring support arm sleeve; the permanent magnet sleeve (104) is sleeved on the outside of the inner permanent magnet (102) in an interference fit manner, and the middle part of the support base plate has an annular boss for sleeve-mounting the hollow shaft (105); The stator assembly (2) comprises: an end cover (201), a stator core (202), and a stator bracket (203); a plurality of stator brackets (203) are evenly and fixedly mounted on the inner end surface of the end cover (201) along the circumferential direction, forming an annular bracket structure as a whole; each stator core (202) is nested and mounted between adjacent stator brackets (203) along the circumferential direction; the oil separator sleeve (13) is configured as an annular spacer structure with one end open, the oil separator sleeve (13) is integrally sleeved on each stator core (202) and the stator bracket (203), and is fixedly connected to the inner end surface of the end cover (201); and the stator core (202), and the assembly structure of the oil separator sleeve (13), the adjacent stator core (202) and the stator bracket (203) are integrally inserted between the annular cavity formed by the inner permanent magnet (102) and the outer permanent magnet (103); An annular mounting seat is provided in the middle of the inner end surface of the end cover (201) of the stator assembly (2), and is sleeved on the outside of the hollow shaft (105) of the rotor assembly (1), and the hollow shaft (105) and the annular mounting seat are connected and supported by a double-row deep groove ball bearing (6); A rotary transformer (3) and a rotary transformer stator bracket (5) are sequentially sleeved on the outer side of the transmission end of the hollow shaft (105); the rotor of the rotary transformer (3) is fixedly sleeved on the hollow shaft (105) and axially positioned; the stator of the rotary transformer (3) is sleeved outside the rotor and axially positioned by an end cover (201) and the rotary transformer stator bracket (5).

2. The permanent magnet synchronous motor with radial double rotor yokeless structure and high torque density according to claim 1, characterized in that: The positioning structure of the stator core (202) in the structure of the stator assembly (2) is: The cross section of each stator core (202) is an "I" shape, and the wedge-shaped grooves formed on the outer sides and inner sides of two adjacent stator cores (202) are respectively plugged into the wedge-shaped support rods at corresponding positions on the stator bracket (203) to perform circumferential positioning of each stator core (202); The oil separator (13) is specifically configured as a stepped annular spacer structure with one end open, and the inner diameter of the closed end is smaller than the inner diameter of the stator sleeve portion. The stator bracket (203) includes a support platform for connecting with the end cover (201) and an outer support rod and an inner support rod for inserting into the outer and inner wedge-shaped grooves of adjacent stator cores (202), and the support platform forms a step portion with the outer support rod and the inner support rod respectively. The stator core (202) is axially positioned by the annular step portion of the oil separator (13) sleeved on the end of each stator core (202) and the support platform on the stator bracket (203).

3. The permanent magnet synchronous motor with radial double rotor yokeless structure and high torque density according to claim 2, characterized in that: An oil separator (13) integrally sleeved on the outside of the stator core (202) forms an end annular cavity at the end of each stator core (202) through a step area at its closed end, and forms a root annular cavity between the stator core (202) and the stator bracket (203), which serve as two annular oil passages for cooling medium; and an axial oil passage is formed in the gap between each winding through the winding wound on each stator core (202); The two annular oil passages and the axial oil passage are used to cool the windings; the root annular cavity and the end annular cavity are connected via the axial oil passage, and an oil inlet and an oil outlet are provided on the end surface of the end cover (201).

4. The permanent magnet synchronous motor with radial double rotor yokeless structure and high torque density according to claim 1, characterized in that: Also includes: Bearing sleeve (7), baffle (8), sleeve (9), stop washer (10), round nut (11); The hollow shaft (105) is configured as a multi-step shaft structure, and an inner shoulder is arranged at the inner end thereof; wherein the inner end face of the double-row deep groove ball bearing (6) abuts against the inner shoulder, and the hollow shaft (105) is sequentially sleeved with a sleeve (9), a retaining washer (10) and a round nut (11) between the double-row deep groove ball bearing (6) and the rotary transformer (3); the inner ring of the double-row deep groove ball bearing (6) is axially positioned by the inner shoulder and the sleeve (9); and the sleeve (9) is axially positioned by the retaining washer (10) and the round nut (11) screwed onto the hollow shaft (105); The bearing sleeve (7) is configured as a sleeve structure having annular retaining rings at both ends, and is integrally sleeved on the outside of the double-row deep groove ball bearing (6). Its inner retaining ring abuts against the end of the annular mounting seat in the end cover (201), and its outer retaining ring abuts against the outer end face of the double-row deep groove ball bearing (6). The baffle plate (8) is sleeved with its step ring on the inner retaining ring of the bearing sleeve (7) and the inner end face of the double-row deep groove ball bearing (6), and the bearing outer ring of the double-row deep groove ball bearing (6) is positioned by the bearing sleeve (7) and the baffle plate (8).

5. The permanent magnet synchronous motor with radial double rotor yokeless structure and high torque density according to claim 4, characterized in that: Also includes: Circlip (4); A middle shoulder and an outer shoulder are sequentially arranged between the inner shoulder of the hollow shaft (105) and the transmission end thereof; the outer end of the sleeve (9) extends out of the middle shoulder and is pressed against the outer end of the sleeve (9) by a stop washer (10) and a round nut (11); The inner end of the rotor of the rotary transformer (3) abuts against the outer shaft shoulder, and the hollow shaft (105) is also sleeved with an elastic retaining ring (4) on the outer side of the rotor of the rotary transformer (3), so that the rotor of the rotary transformer (3) is axially positioned by the outer shaft shoulder of the hollow shaft (105) and the elastic retaining ring (4).

6. The permanent magnet synchronous motor with radial double rotor yokeless structure and high torque density according to claim 1, characterized in that: Also includes: Balancing ring (12); An annular groove is provided on the outer end surface of the bracket bottom plate of the rotor bracket (101) for embedding and installing a balancing ring (12); the balancing ring (12) is fixedly connected to the bracket bottom plate of the rotor bracket (101) by bolts; a plurality of holes are provided on the end surface of the balancing ring (12) along the circumferential direction; and the dynamic balance of the motor is adjusted by inserting tungsten rods into the holes of the balancing ring (12).

7. The permanent magnet synchronous motor with a radial double rotor yokeless structure and high torque density according to any one of claims 1 to 6, characterized in that: An annular flange is formed on the outer end surface of the end cover (201) in the stator assembly (2) and is used to install the permanent magnet synchronous motor on an engine or a traction platform and is fixedly mounted on the flanges at both ends by annular clamps.

8. The permanent magnet synchronous motor with a radial double rotor yokeless structure and high torque density according to any one of claims 1 to 6, characterized in that: The inner permanent magnet (102) and the outer permanent magnet (103) in the rotor assembly (1) are respectively divided into two sections in the axial direction, and each section is composed of 320 small permanent magnets on the circumference, with a total of 1280 small permanent magnets.

9. The permanent magnet synchronous motor with a radial double rotor yokeless structure and high torque density according to any one of claims 1 to 6, characterized in that: Each stator iron core (202) is in an I-shaped shape and is composed of 72 small iron cores evenly distributed in the circumferential direction.

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