Cooling structure of motor

Abstract

The utility model provides a cooling structure of a motor. The cooling structure comprises a stator structure and a rotor structure. The stator structure comprises stator windings arranged at the two ends; the rotor structure comprises a rotor hollow rotating shaft, a rotor iron core, a permanent magnet, at least one oil distribution ring and a flow guide mechanism; the rotor iron core and the oil distribution ring are fixedly connected to the outer surface of the rotor hollow rotating shaft; wherein one end of the rotor hollow rotating shaft is a liquid inlet end, and the other end is a liquid outlet end; a plurality of magnet cavities are arranged in the rotor core structure, and the permanent magnets are fixedly connected in the magnet cavities; the rotor iron core is divided into a plurality of sections of rotor iron core structures by the oil separation rings; the oil distribution ring is provided with two-way channels corresponding to the magnet cavities on the two sides of the oil distribution ring respectively, the two input ends of the two-way channels are communicated with the rotor hollow rotating shaft, and the two output ends of the two-way channels are communicated with the magnet cavities on the two sides respectively. According to the utility model, the temperature of the permanent magnet and the stator end winding in the motor can be effectively reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a cooling structure of a motor. Background Art

[0002] As the power component of new energy vehicles, the motor generates torque to drive the vehicle. Permanent magnet motors account for the majority of new energy vehicle motors. Permanent magnets are installed on the rotor of permanent magnet motors. The permanent magnets generate a magnetic field, which interacts with the magnetic field generated by the stator winding to generate electromagnetic torque to drive the rotor to rotate. When the motor is working, the rotor permanent magnets will generate a lot of heat. The thermal stability of permanent magnet materials is low. If they work in an environment exceeding the heat resistance temperature, the permanent magnets will irreversibly demagnetize, the magnetic moment will be weakened or disappear accordingly, and the motor output performance will decrease. The motor structure can be as follows: Figure 1 shown.

[0003] Therefore, the motor is generally designed with a rotor heat dissipation structure to promptly remove the heat of the rotor permanent magnet, increase the operating temperature threshold and continuous output capacity, and increase the service life of the motor. In the prior art, many motor rotors are equipped with fans for air cooling. This structure is simple but has limited heat dissipation capacity, and there will be mechanical losses when the fan rotates. There is also a solution to pass oil through the hollow rotor shaft (such as Figure 2 ), a hole is opened on the shaft, and the rotor rotates to throw oil to cool the motor stator, but the cooling oil mainly cools the rotor core in contact with the shaft, and a small amount cools the rotor permanent magnet.

[0004] See also Figure 3 At present, there is a new heat dissipation structure in the existing technology, which is an "S" type reciprocating heat dissipation structure. Its structure is mainly to design oil grooves and oil inlet and outlet holes on the end face pressure plate. The cooling oil flows into the permanent magnet slot of the core along the end face oil groove to directly cool the permanent magnet. After flowing to the other end face, it flows out to both sides, effectively reducing the temperature of the permanent magnet. However, this design also has some disadvantages:

[0005] 1. Cooling oil asynchronism leads to inconsistent temperature: In the "S" type reciprocating circulation heat dissipation structure, when the cooling oil flows to the other side of the core end face, due to the difference in flow paths, the temperatures of the cooled cores and permanent magnets on both sides are inconsistent. The cooling effect is better and the temperature is lower near the oil inlet end. The longer the oil flow path, the higher the oil temperature, and the worse the cooling effect is at the back of the path.

[0006] 2. The effect of spraying oil on the rotor cover plates at both ends to cool the stator winding of the motor is quite different: the cooling oil is divided when it passes through the iron core for the first time and reaches the end. Some of the cooling oil is sprayed onto the stator winding on the same side through the oil hole, and most of it flows back to the iron core to reach the other end, where it is sprayed out to cool the stator winding at the other end. The cooling oil temperature at both ends is inconsistent, and because the gas pressure at the rotor ends is different at different speeds, the air pressure difference between the inside and outside of the rotor cover is also different. The end with reflux has different oil spraying amounts at different speeds, and the oil pump pressure is difficult to control the oil spraying amount at both ends to be consistent, which will lead to uneven temperature fields at both ends of the windings.

[0007] In order to solve the above problems, it is necessary to propose a new cooling structure for the motor. Utility Model Content

[0008] In view of the shortcomings of the prior art described above, the purpose of the utility model is to provide a cooling structure for a motor, which is used to solve the problem in the prior art that the rotor permanent magnets will generate a lot of heat, the permanent magnet material has low thermal stability, and if it works in an environment exceeding the heat resistance temperature, it will cause irreversible demagnetization of the permanent magnets, and the magnetic moment will be correspondingly weakened or disappear, resulting in a decrease in the output performance of the motor.

[0009] In order to achieve the above-mentioned purpose and other related purposes, the utility model provides a cooling structure of a motor, comprising:

[0010] stator structure and rotor structure;

[0011] The stator structure includes stator windings arranged at two ends;

[0012] The rotor structure includes a rotor hollow shaft, a rotor core, a permanent magnet, at least one oil separator ring and a flow guide mechanism, wherein the rotor core and the oil separator ring are fixedly connected to the outer surface of the rotor hollow shaft; wherein,

[0013] One end of the hollow rotor shaft is a liquid inlet end, and the other end is a liquid outlet end;

[0014] A plurality of magnet cavities are provided in the rotor core structure, and the permanent magnets are fixedly connected in the magnet cavities;

[0015] The oil dividing ring divides the rotor core into multiple rotor core structures;

[0016] The oil separator ring is provided with bidirectional channels corresponding to the magnet cavities on both sides thereof, the two input ends of the bidirectional channels are both connected to the hollow shaft of the rotor, and the two output ends of the bidirectional channels are respectively connected to the magnet cavities on both sides;

[0017] The flow guiding mechanisms are located at both ends of the stator structure, and are used to divert the cooling oil in the magnet cavity at the two ends to the stator winding.

[0018] Preferably, the magnet cavities are distributed in an array along the central axis of the hollow rotor shaft.

[0019] Preferably, each of the magnet cavities is composed of at least one cavity.

[0020] Preferably, in each group of the magnet cavities, the cavities therein are symmetrically arranged.

[0021] Preferably, the cross-section of the bidirectional channel is a branch-like forked shape.

[0022] Preferably, the magnet cavities are all composed of cavities of the same size, and the flow rate of the cooling oil diverted from the output end of the bidirectional channel to each cavity is consistent or tends to be consistent.

[0023] Preferably, in each group of the magnet cavities, the sizes of the cavities are different, and the flow rate of the cooling oil diverted from the output end of the bidirectional channel to each of the cavities is determined by the size of the cavity.

[0024] Preferably, end covers for fixing the rotor core are provided at both ends of the rotor core structure.

[0025] Preferably, the guide mechanism is arranged on the inner surface of the end cover plate: the inner surfaces of the end cover plates at both ends are respectively provided with guide grooves and oil outlets corresponding to each group of the magnet cavities, the guide grooves are connected with the corresponding magnet cavities, and the oil outlets are used to divert the cooling oil in the guide grooves to the stator windings.

[0026] Preferably, the cross-sectional area of ​​the cavity formed by the bifurcated oil passage of the oil dividing ring and the rotor core and the cross-sectional area of ​​the oil outlet in the end cover plate are not less than 1 mm 2 .

[0027] Preferably, a balancing disk is fixedly connected to the outer surface of the end cover plate.

[0028] Preferably, a weight-reducing hole is also provided in the rotor core.

[0029] As described above, the cooling structure of the motor of the utility model has the following beneficial effects:

[0030] The utility model can effectively reduce the temperature of the permanent magnet and the stator end winding in the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Shown is a schematic diagram of the motor structure of the prior art;

[0032] Figure 2 Shown is a schematic diagram of the prior art in which cooling oil is passed through the hollow shaft of the rotor;

[0033] Figure 3 Shown is a schematic diagram of an "S" type reciprocating cycle heat dissipation structure of the prior art;

[0034] Figure 4 Shown is an exploded schematic diagram of various components of the rotor structure of the utility model;

[0035] Figure 5 Shown is a schematic diagram of the heat dissipation structure of the utility model;

[0036] Figure 6 Shown is a schematic diagram of the oil separator structure of the utility model;

[0037] Figure 7 Shown is a schematic diagram of the end cover structure of the utility model;

[0038] Figure 8 Shown is a schematic diagram of the cross-sectional structure of the rotor core of the utility model;

[0039] Fig. 9 Shown is a schematic diagram of the installation of large and small permanent magnets of the utility model;

[0040] Fig.10 , 11 Shown is a schematic cross-sectional view of the magnet cavity of the utility model

[0041] Figures 12 to 18 Shown is a partial cross-sectional schematic diagram of the oil separator ring of the present utility model. DETAILED DESCRIPTION

[0042] The following is an explanation of the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0043] See also Figure 4 The utility model provides a cooling structure of a motor, comprising:

[0044] The stator structure 70 and the rotor structure; the rotor structure may be a 4-pole, 6-pole, 8-pole, 12-pole or other multi-pole motor rotor;

[0045] The stator structure 70 includes stator windings 701 disposed at both ends;

[0046] The rotor structure includes a rotor hollow shaft 50, a rotor core, a permanent magnet 80, at least one oil separator 10 and a flow guide mechanism. The rotor core and the oil separator 10 are fixedly connected (for example, welded, clamped, etc.) to the outer surface of the rotor hollow shaft 50; wherein,

[0047] One end of the hollow rotor shaft 50 is a liquid inlet end, and the other end is a liquid outlet end;

[0048] A plurality of magnet cavities are provided in the rotor core structure, and permanent magnets are fixedly connected in the magnet cavities;

[0049] The oil dividing ring 10 divides the rotor core into multiple sections of the rotor core structure;

[0050] The oil separator ring 10 is provided with bidirectional channels corresponding to the magnet cavities on both sides thereof, and both input ends of the bidirectional channels are connected to the hollow rotor shaft 50, and both output ends of the bidirectional channels are connected to the magnet cavities on both sides respectively;

[0051] In some embodiments, the magnet cavities are each comprised of at least one cavity.

[0052] For example, see Figure 4 The rotor core comprises an oil separator ring 10, and first and second rotor core structures (20, 60) symmetrically arranged along the oil separator ring 10, the first and second rotor core structures (20, 60) respectively comprising first and second rotor cores (201, 601), the first and second rotor core structures (20, 60) being provided with a plurality of groups of first and second magnet cavities (202, 602) symmetrically arranged, and the permanent magnets 80 being fixedly connected (e.g., clamped) in the first and second magnet cavities (202, 602); the oil separator ring 10 may be made of metal material, or may be made of polymer or composite material, and may be formed by machining, casting, injection molding, or the like;

[0053] A mounting groove can be provided in the magnet cavity, and the mounting groove uses a mechanical method to fix the permanent magnet 80. The permanent magnet 80 has certain gaps at both ends of the mounting groove. The gaps of the permanent magnet 80 between two adjacent stacked cores are interconnected to form an axial oil channel. When the cooling oil fills the oil channel of the oil separator ring 10, it continues to flow along the axial oil channel toward the end of the core, flows through the adjacent rotor core and the permanent magnet 80, and the cooling oil directly contacts the permanent magnet 80 and takes away the heat.

[0054] Specifically, see Fig. 9 The first and second magnet cavities (202, 602) are provided with installation gaps and fixing protrusions. The installation gaps are used to set the permanent magnets 80, and the fixing protrusions are used to fix the permanent magnets 80.

[0055] In some embodiments, the magnet cavities are distributed in an array along the central axis of the hollow rotor shaft 50 .

[0056] In some embodiments, the magnet cavities are each comprised of at least one cavity.

[0057] In some embodiments, in each group of magnet cavities, the cavities therein are symmetrically arranged. For example, if a group of magnet cavities has cavities of different sizes, the large cavities in the group of magnet cavities are symmetrically arranged, and the small cavities are also symmetrically arranged.

[0058] For example, see Figure 8 The cooling structure design of the embodiment of the utility model is suitable for rotor cores with large and small cavity arrangements, which are double V-shaped or multi-V-shaped, please refer to Fig.10 and Fig.11 The cooling structure design of the embodiment of the utility model is also applicable to the rotor core with V-shaped, V-shaped and other cavity arrangements.

[0059] The oil separator ring 10 is provided with bidirectional channels corresponding to the magnet cavities on both sides thereof, and both input ends of the bidirectional channels are connected to the hollow rotor shaft 50, and both output ends of the bidirectional channels are connected to the magnet cavities on both sides respectively;

[0060] For example, see Figure 5 When the number of the oil separator ring 10 is one, the oil separator ring 10 is provided with a bidirectional channel 101 corresponding to the first and second magnet cavities (202, 602), respectively, and both input ends of the bidirectional channel 101 are connected to the hollow rotor shaft 50, and both output ends of the bidirectional channel 101 are connected to the first and second magnet cavities (202, 602), respectively;

[0061] The oil pump passes the cooling oil into the cavity of the hollow rotor shaft 50. The oil separator ring 10 is provided with a plurality of oil separation holes. The cooling oil enters the rotor through the oil separation holes. It is necessary to ensure that the cooling oil can reach the position of the shaft oil separator ring 10 and have sufficient pressure difference to be pumped into the rotor.

[0062] Through the design of the one-to-two bidirectional channel 101 and the segmented bifurcated channel, the cooling oil directly cools the permanent magnet 80, effectively reducing the temperature of the motor. The cooling oil quickly takes away the heat from the key heat-generating parts, achieving efficient heat dissipation.

[0063] In some embodiments, the magnet cavities are composed of cavities of the same size, for example, the first and second magnet cavities (202, 602) have cavities of the same size, and the flow rate of the cooling oil diverted from the output end of the bidirectional channel 101 to each cavity is consistent or tends to be consistent.

[0064] In some embodiments, in each group of magnet cavities, the magnet cavities are composed of cavities of different sizes. For example, the first and second magnet cavities (202, 602) have cavities of different sizes, and the flow rate of cooling oil diverted from the output end of the bidirectional channel 101 to each cavity is determined by the size of the cavity.

[0065] The cooling oil is first divided into two branches by the oil dividing ring 10 before entering the rotor structure, and flows to the two end faces of the rotor structure respectively, to ensure that the amount of oil at both ends of the rotor structure is the same. For example, for a rotor core with different cavities, the permanent magnets may include large and small permanent magnets, and enter the bifurcated oil channel. A part of the cooling oil is diverted to the small permanent magnet area, and the other part flows to the large permanent magnet area. The size and flow of this part of the oil channel are designed according to the cooling requirements of the large and small permanent magnets to ensure that the cooling effects of the two are similar.

[0066] In some embodiments, see Figure 6 The cross section of the bidirectional channel 101 is a branch-like forked shape.

[0067] The design shape of the bifurcated oil channel can be Figures 12 to 18 As shown, it can be a single-fork or multi-fork structure, and its shape can also be other designs that can ensure that the oil channel on the oil distribution ring 10 can guide the cooling oil into the slots of each permanent magnet 80 to meet the cooling requirements. No specific limitation is made here.

[0068] In some embodiments, the thickness of the oil separator ring 10 is 4 to 12 mm, and other thicknesses may also be set as required.

[0069] The cooling structure of the embodiment of the present invention is not limited to one oil separator ring 10 , and it is also feasible to install multiple oil separator rings 10 in the motor rotor.

[0070] In some embodiments, end covers 30 for fixing the rotor core are further provided at both ends of the rotor core structure.

[0071] In some embodiments, the guide mechanism is arranged on the inner surface of the end cover: the inner surfaces of the end covers 30 at both ends are respectively provided with guide grooves 301 corresponding to each group of magnet cavities and oil outlets 302, the guide grooves 301 are connected to the corresponding magnet cavities, and the oil outlets 302 are used to divert the cooling oil in the guide grooves to the stator windings 701.

[0072] For example, when the number of oil separator rings is one, refer to Figure 5 The inner surfaces of the end covers 30 at both ends are respectively provided with guide grooves 301 corresponding to each group of the first and second magnet cavities and oil outlets 302. The guide grooves 301 are connected to the corresponding first and second magnet cavities (202, 602), and the oil outlets 302 are used to divert the cooling oil in the guide grooves 301 to the stator windings 701.

[0073] In some embodiments, see Figure 7The guide groove 301 and the oil outlet 302 can be formed by the reinforcing ribs. After the cooling oil reaches the rotor end face, it reaches the end cover 30 of the end face. The reinforcing ribs on the end cover 30 serve as oil passages on the rotor end face to collect the cooling oil flowing out of the permanent magnet 80 slots. The cooling oil passes through the outer ring reinforcing ribs of the end cover 30 and finally flows out through the oil outlet 302 on the reinforcing ribs. The cooling oil flows to the stator winding 701 to reduce the temperature of the stator winding 701.

[0074] The design can maintain the temperature consistency at both ends of the rotor to the greatest extent, avoid the problem of uneven temperature field caused by excessive temperature difference between inlet and outlet cooling oil due to the cooling channel (such as the first and second magnet cavities (202, 602)) being too long and curved, and reduce the impact of thermal stress on the motor structure, thereby improving the reliability and working stability of the motor. The cooling strategy is easy to design and control.

[0075] The cooling oil flows from the end surface of the core to the stator winding 701, effectively reducing the temperature of the end of the stator winding 701. The stator winding 701 is the part of the motor that generates the most heat. By reducing the temperature of the stator winding 701, the continuous performance of the motor can be improved and failures caused by excessive temperature can be reduced.

[0076] In some embodiments, to avoid atomization of the cooling oil, the cross-sectional area of ​​the cavity formed by the bifurcated oil passage of the oil dividing ring 10 and the rotor core and the cross-sectional area of ​​the oil outlet 302 in the end cover plate are not less than 1 mm 2 .

[0077] In some embodiments, a balancing disc 40 is fixedly connected to the outer surface of the end cover plate 30 .

[0078] In some embodiments, a weight-reducing hole is further provided in the rotor core. The design of the weight-reducing hole can effectively reduce the overall weight of the motor and achieve lightweighting of the motor. This helps to improve the dynamic response and energy-saving performance of the motor, reduce installation costs and transportation costs, and improve power density.

[0079] The cooling effect comparison of different solutions is shown in the following table:

[0080]

[0081] When the continuous performance of the motors is the same, the cooling effect of the embodiment of the present invention is the best.

[0082] It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the present invention. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0083] In summary, the utility model can effectively reduce the temperature of the permanent magnet and the stator end winding in the motor. Therefore, the utility model effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0084] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A cooling structure for a motor, characterized in that: include: stator structure and rotor structure; The stator structure includes stator windings arranged at two ends; The rotor structure includes a rotor hollow shaft, a rotor core, a permanent magnet, at least one oil separator ring and a flow guide mechanism, wherein the rotor core and the oil separator ring are fixedly connected to the outer surface of the rotor hollow shaft; wherein, One end of the hollow rotor shaft is a liquid inlet end, and the other end is a liquid outlet end; A plurality of magnet cavities are provided in the rotor core structure, and the permanent magnets are fixedly connected in the magnet cavities; The oil dividing ring divides the rotor core into multiple rotor core structures; The oil separator ring is provided with bidirectional channels corresponding to the magnet cavities on both sides thereof, the two input ends of the bidirectional channels are both connected to the hollow shaft of the rotor, and the two output ends of the bidirectional channels are respectively connected to the magnet cavities on both sides; The flow guide mechanisms located at both ends of the stator structure are used to divert the cooling oil in the magnet cavity at the two ends to the stator winding.

2. The cooling structure of the motor according to claim 1, characterized in that: The magnet cavities are distributed in an array along the central axis of the hollow rotor shaft.

3. The cooling structure of the motor according to claim 1, characterized in that: The magnet cavities are each composed of at least one cavity.

4. The cooling structure of the motor according to claim 3, characterized in that: In each group of the magnet cavities, the cavities therein are symmetrically arranged.

5. The cooling structure of the motor according to claim 3 or 4, characterized in that: The cross section of the bidirectional channel is a branch-like forked shape.

6. The cooling structure of the motor according to claim 5, characterized in that: The magnet cavities are all composed of cavities with the same size, and the flow rate of the cooling oil distributed from the output end of the bidirectional channel to each cavity is consistent or tends to be consistent.

7. The cooling structure of the motor according to claim 5, characterized in that: In each group of the magnet cavities, the sizes of the cavities are different, and the flow rate of the cooling oil diverted from the output end of the bidirectional channel to each of the cavities is determined by the size of the cavity.

8. The cooling structure of the motor according to claim 1, characterized in that: End covers for fixing the rotor core are also provided at both ends of the rotor core structure.

9. The cooling structure of the motor according to claim 8, characterized in that: The cross-sectional area of ​​the cavity formed by the bifurcated oil passage of the oil dividing ring and the rotor core and the cross-sectional area of ​​the oil outlet in the end cover plate are not less than 1mm 2 .

10. The cooling structure of the motor according to claim 8, characterized in that: The guide mechanism is arranged on the inner surface of the end cover plate: the inner surfaces of the end cover plates at both ends are respectively provided with guide grooves corresponding to each group of the magnet cavities and oil outlets, the guide grooves are connected with the corresponding magnet cavities, and the oil outlets are used to divert the cooling oil in the guide grooves to the stator windings.

11. The cooling structure of the motor according to claim 8, characterized in that: A balancing disk is fixedly connected to the outer surface of the end cover plate.

12. The cooling structure of the motor according to claim 1, characterized in that: The rotor core is also provided with weight-reducing holes.

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