Oil-air hybrid cooling electric drive system

Abstract

The invention discloses an oil-air hybrid cooling electric drive system which comprises a motor assembly and a speed reducer assembly, the motor assembly comprises a motor shell and a machine core assembly located in the motor shell, and the machine core assembly comprises a stator assembly and a rotor assembly. The speed reducer assembly comprises a speed reducer shell assembled at the top of the motor shell and a speed reducer internal assembly located in the speed reducer shell, the top end of a rotating shaft of the rotor assembly extends into the speed reducer shell to output power, an oil pan is assembled at the bottom of the motor shell, and an oil pump oil storage cavity is formed between the oil pan and the bottom of the motor shell; the bottom end of a rotating shaft of the rotor assembly extends into an oil storage cavity of the oil pump and is in transmission connection with the power input end of the oil pump, oil inlet channels which are connected in series are formed in the motor shell and the speed reducer shell, and the oil outlet end of the oil pump can convey cooling oil into the speed reducer shell through the oil inlet channels. An oil return channel used for guiding cooling oil back to the oil storage cavity of the oil pump is further formed in the motor shell and the speed reducer inner shell.

Description

Technical Field

[0001] This invention relates to the field of electric drive technology for low-altitude aircraft, and more specifically to an oil-air hybrid cooling electric drive system. Background Technology

[0002] With the booming development of the low-altitude economy, rotor electric drive systems are rapidly evolving towards miniaturization, lightweighting, and high power density. High power density means generating more heat per unit time. When an aircraft is at low altitude or hovering, the airflow velocity is low, and the heat dissipation efficiency decreases. This requires the electric drive system to have an efficient and reliable heat dissipation structure.

[0003] Currently, traditional rotor electric drive systems typically employ separate air-cooled or liquid-cooled systems. Air-cooled systems are simple in structure and lightweight, but their heat dissipation efficiency is relatively low, especially when the aircraft is hovering or flying at low speeds, insufficient airflow may lead to inadequate heat dissipation. Liquid-cooled systems (such as water-cooled or oil-cooled systems) have powerful heat dissipation capabilities, but the systems are relatively complex and often require additional cooling systems, such as water tanks, radiators, oil-water heat exchangers, and external fuel supply systems. This not only increases the complexity and weight of the system but also contradicts the requirement for lightweight aircraft.

[0004] Furthermore, high-power applications such as large-scale eVTOL and unmanned helicopters rely heavily on reducers to obtain enormous torque, and the reducers themselves require independent lubrication systems to ensure the reliability of gear transmission. This results in the need for two separate systems (cooling and lubrication) for both the motor and the reducer, leading to a complex, heavy, and poorly integrated electric drive system. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide an oil-air hybrid cooling electric drive system that simultaneously meets the cooling and lubrication requirements of equipment, reduces structural complexity, and lightens the overall weight.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: An oil-air hybrid cooling electric drive system includes a motor assembly and a reducer assembly. The motor assembly includes a motor housing and a core assembly located within the motor housing. The core assembly includes a stator assembly and a rotor assembly. The reducer assembly includes a reducer housing mounted on top of the motor housing and an internal reducer assembly located within the reducer housing. The top end of the rotor assembly's shaft extends into the reducer housing and is drive-connected to the power input end of the internal reducer assembly. An oil pan is mounted at the bottom of the motor housing, forming an oil pump reservoir between the oil pan and the bottom of the motor housing. An oil pump is installed in the oil pump reservoir and at the bottom of the motor housing. The bottom end of the rotor assembly's shaft extends into the oil pump reservoir and is drive-connected to the power input end of the oil pump. Series-connected oil inlet channels are formed within the motor housing and the reducer housing. The oil outlet of the oil pump can deliver cooling oil to the reducer housing through the oil inlet channels. A return oil channel is also formed within the motor housing and the reducer housing to guide the cooling oil flowing through the internal reducer assembly and the core assembly back to the oil pump reservoir.

[0007] In this invention, the motor, reducer, and oil pump are directly assembled through a housing, integrating two power assemblies and greatly reducing the system's size and weight. The oil pump is driven by the motor shaft, eliminating the need for an external power source. Cooling oil is delivered to the parts requiring lubrication and cooling via internal oil passages (inlet and return channels), and can then be automatically recycled, achieving a dual-purpose oil function.

[0008] As an optimization, the internal components of the reducer are planetary gear reducers. The oil inlet channel includes a main oil passage on the reducer housing. The main oil passage has at least two outlet branches, including a first outlet and a second outlet. The first outlet is directly opposite the meshing point of the planetary gear and the internal gear ring in the planetary gear reducer assembly, spraying cooling oil onto it. The second outlet connects to the mounting hole of the front bearing in the planetary gear reducer assembly. The first outlet directly sprays oil onto the gear meshing point, which is the location in the reducer with the highest load and the greatest need for lubrication and heat dissipation. The second outlet ensures reliable lubrication of the reducer's front bearing.

[0009] As an optimization, the oil outlet branch also includes a third oil outlet, which communicates with an internal oil passage located within the output shaft of the planetary reduction assembly. The outlet end of the internal oil passage is positioned directly opposite the meshing point between the first-stage planetary gear in the planetary reduction assembly and the rotating shaft of the rotor assembly, for spraying cooling oil onto it. This adds a third lubrication path, directing cooling oil through the central channel of the output shaft to another critical gear meshing point for lubrication.

[0010] As an optimization, the planetary reduction assembly includes an oil collection tray disposed on the planetary carrier, with an oil collection tray outlet. An oil passage is provided within the planetary gear pins of the planetary reduction assembly. The oil collection tray outlet connects to the inlet of the oil passage, and the oil passage has an oil outlet for lubricating the planetary gear needle roller bearings in the planetary reduction assembly. The oil collected by the collection tray is directly delivered to the planetary gear needle roller bearings.

[0011] As an optimization, the planetary carrier of the planetary reduction assembly is provided with a planetary carrier oil return hole, which guides the cooling oil in the reducer housing to the rear bearing of the planetary reduction assembly. The front end of the rotor assembly is provided with a front dynamic balancing plate, the end face of which is provided with a centrifugal guide structure. The centrifugal guide structure is a ramp surrounding the central shaft of the rotor assembly, used to throw the cooling oil reaching its surface towards the windings of the stator assembly under centrifugal force. This provides a directional oil return path from the reducer cavity to the motor bearing, ensuring that the oil can return through the rear bearing of the planetary reduction assembly and lubricate the front bearing of the motor. Furthermore, the centrifugal force of the rotating rotor throws the oil reaching the dynamic balancing plate towards the end of the stator windings, which generate more heat, improving the cooling efficiency of the winding ends.

[0012] As an optimization, the oil return channel includes multiple reducer oil return holes located at the top of the motor housing. These holes guide cooling oil from the reducer housing to the upper end of the stator assembly windings. The stator core of the stator assembly has core oil grooves on its outer periphery. These grooves cooperate with the inner wall of the motor housing to form core oil channels. These channels guide cooling oil through the upper and lower ends of the stator core in the stator assembly for cooling. Direct spray cooling of the winding ends is achieved through the oil return holes, and the cooling oil flows through the oil channels between the stator core and the housing, directly carrying away the hysteresis and eddy current losses (iron losses) of the core.

[0013] As an optimization, the oil return channel further includes at least one motor oil return groove arranged on the inner circumferential surface of the motor housing. The motor oil return groove is used to connect the upper and lower cavities of the core assembly located within the motor housing. At least one of the motor housing and the reducer housing has a heat dissipation structure on its outer surface. Internal oil cooling conducts heat to the outer shell, while external air cooling (heat dissipation fins, etc.) utilizes the airflow during flight to ultimately dissipate the heat.

[0014] As an optimization, an oil baffle ring is provided at the front end of the stator core in the stator assembly. The oil baffle ring is used to form an oil reservoir at the front end of the stator core in the stator assembly for collecting cooling oil and soaking part of the upper winding in the stator assembly. The inner bottom surface of the motor housing is provided with an oil baffle rib, which is used to form an oil reservoir on the inner bottom surface of the motor housing for collecting cooling oil and soaking part of the lower winding of the stator assembly. The oil return channel also includes a motor oil return hole, a bearing oil guide groove, and a bearing oil return groove located at the bottom of the motor housing. The motor oil return hole is through-hole, used to guide a portion of the cooling oil overflowing into the inner side of the oil baffle to the oil pump reservoir. The bearing oil guide groove is located on the inner bottom surface of the motor housing, used to guide a portion of the cooling oil overflowing into the inner side of the oil baffle to the rear bearing of the core assembly. The bearing oil return groove is located on the outer bottom surface of the motor housing, used to guide the cooling oil flowing through the rear bearing of the core assembly to the oil pump reservoir. The oil baffle ring and oil baffle form an oil pool, allowing the winding ends to be directly immersed in the cooling oil, improving cooling efficiency. Finally, while guiding the cooling oil to the oil pump reservoir, it also guides the cooling oil to lubricate the rear bearing of the motor.

[0015] As an optimization, the oil pump is a rotary pump, and the bottom end of the rotor assembly's shaft directly mates with the center hole of the inner rotor of the rotary pump or is connected to the inner rotor of the rotary pump through the gear shaft assembly of the oil pump reducer.

[0016] Compared with the prior art, the present invention has the following advantages: (1) By integrating the motor, reducer and oil pump into one unit and using an internal oil circuit system to solve the two major problems of reducer lubrication and motor heat dissipation at the same time, the oil can be used for two purposes, reducing the number of parts, reducing system weight and complexity; (2) The cooling oil can be sprayed directly onto the ends of the motor windings through the internal oil channels and flow through the stator core. It also forms an oil pool at both ends of the windings to soak part of the windings, directly carrying away the heat generated by the copper and iron losses during motor operation. This significantly improves the efficiency of motor cooling. (3) The multiple oil outlets on the reducer lubricate the gear meshing parts and bearings respectively; and through the oil passages in the oil collection plate and planetary gear pin shaft, the hard-to-reach planetary gear needle roller bearings are effectively lubricated. (4) The cooling oil carries the internal heat to the shell, while the heat dissipation structure outside the shell uses the airflow during flight to remove the heat. Combining internal oil cooling and external air cooling, it takes into account both heat dissipation efficiency and system lightweight requirements.

[0017] Attached image description Figure 1 A schematic diagram of the overall flow direction of the cooling oil in this invention; Figure 2 This is a cross-sectional view of the present invention in the XZ coordinate direction; Figure 3 This is a cross-sectional view of the present invention in the YZ coordinate direction; Figure 4This is a top view of the invention without an oil pan; Figure 5 This is a top view of the oil pump in this invention; Figure 6 This is a cross-sectional view of the oil pump in this invention; Figure 7 This is a top view of the rear end cover of the motor in this invention; Figure 8 This is a cross-sectional view of the rear end cover of the motor in this invention; Figure 9 This is a three-dimensional structural diagram of the motor housing (excluding the front and rear end covers) in this invention; Figure 10 This is a three-dimensional structural diagram of the motor front end cover in this invention; Figure 11 This is a three-dimensional structural diagram of the oil collection tray in this invention; Figure 12 This is a three-dimensional structural schematic diagram of the stator assembly in this invention; Figure 13 This is a three-dimensional structural schematic diagram of the oil baffle ring in this invention; Figure 14 This is a cross-sectional view of the front dynamic balancing plate in this invention; Figure 15 This is a schematic diagram of the external airflow direction of the present invention; Figure 16 This is a schematic diagram showing the detailed flow direction of the cooling oil in this invention; Figure 17 This is a three-dimensional structural diagram of the rotor assembly and the oil pump connected by an oil pump reducer gear shaft assembly in this invention.

[0018] Labels in the attached diagram: Motor assembly (1), reducer assembly (2), motor rear end cover (3), oil passage (3A), oil pump mounting position (3B), oil groove (3C), oil return hole (3D), oil baffle (3E), oil return groove (3F), oil guide rib (3G), resolver mounting position (3H), motor front end cover (4), oil passage (4A), oil return hole (4B), motor housing (5), oil passage (5A), heat dissipation fins (5B), oil return groove (5C), motor rear cover plate (10), motor side cover plate (11), oil pan (12), oil baffle ring (13), buckle (1 3A), stator assembly (15), busbar (16), motor rear bearing (17), stator core (19), oil groove (19A), front dynamic balance plate (23), ramp (23A), clearance groove (23B), rotor assembly (24), rear dynamic balance plate (28), pressure ring (29), motor shaft (32), motor front bearing (33), rotary transformer rotor (37), rotary transformer stator (38), mechanical oil pump assembly (39), oil inlet (39A), oil passage (39B), oil outlet (39A). C), oil pump housing (40), oil pump cover plate (41), oil pump inner rotor (42), oil pump outer rotor (43), oil pump reducer gear shaft assembly (44), oil pump first-stage reduction gear (45), oil pump second-stage reduction gear (46), second-stage reduction gear spindle (47), filter element (48), terminal block (49), planetary reducer gear shaft assembly (50), reducer planetary carrier (51), oil return hole (51A), reducer output shaft (53), oil passage (53A), oil outlet (53B), first-stage planetary gear (54), Second-stage planetary gear (55), Planetary gear pin (56), Oil passage (56A), Oil outlet (56B), Needle roller bearing (58), Reducer front bearing (59), Internal gear ring (60), Hole snap ring (61), Reducer housing (62), Oil passage (62A), Oil outlet (62B / 62C / 62D), Oil return hole (62E), Reducer rear bearing (65), Cup plug (66), Cylinder liner (67), Oil hole (67A), Oil collection plate (69), Oil outlet (69A), Oil seal (71). Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] Example 1 like Figures 1 to 16 As shown in the figure, this specific embodiment provides a detailed description of an oil-air hybrid cooling electric drive system employing the relevant structure of the present invention.

[0021] The system includes a motor assembly (1) and a reducer assembly (2). The motor assembly (1) includes a motor housing (5), a front cover (4), a rear cover (3), a stator assembly (15), a rotor assembly (24), a front bearing (33), a rear bearing (17), an oil baffle (13), a mechanical oil pump (39), a filter element (48), and an oil pan (12). The stator assembly (15) is fixed inside the motor housing (5), the front cover (4) and the rear cover (3) are fixed on the motor housing (5), the bearing (33 / 17) is fitted on the rotor shaft (32) of the rotor assembly (24), the rotor assembly (24) is mounted on the bearing holes of the front cover (4) and the rear cover (3) through the bearing (33 / 17), the mechanical oil pump (39) is mounted on the rear cover (3), its center hole is matched with the rear end of the shaft (32), and the filter element (48) is mounted on the oil inlet (39A) of the mechanical oil pump (39). The feature is that the rear end cover (3) is provided with an oil passage (3A), which is connected to the oil outlet (39C) of the oil pump (39); the motor housing (5) is provided with an oil passage (5A) connected to the oil passage (3A) of the rear end cover (3); and the front end cover (4) is provided with an oil passage (4A) connected to the oil passage (5A) of the housing. The oil passage connects the oil pump outlet (39C), the oil passage (3A) of the rear end cover, the oil passage (5A) of the housing, and the oil passage (4A) of the front end cover, and finally connects to the oil passage of the reducer assembly (2).

[0022] The reducer assembly (2) includes components such as a reducer housing (62), a planetary reducer gear shaft assembly (50), a reducer front bearing (59), a reducer rear bearing (65), an oil seal (71), and an oil collection tray (69). The internal gear ring (60) of the planetary reducer gear shaft assembly (50) is fixed on the reducer housing (62), the reducer output shaft (53) is fixed on the reducer planetary carrier (51), the reducer front bearing (59) is sleeved on the reducer output shaft (53), and the reducer rear bearing (65) is sleeved on the reducer planetary carrier (51). The bearings (59 / 65) are installed on the bearing holes of the motor front end cover (4) and the reducer housing (62), and the oil collection tray (69) is installed on the planetary carrier (51). The feature is that the reducer housing (62) is provided with an oil passage (62A) that connects to the oil outlet (4A) of the motor assembly (1), the reducer housing (62) is provided with an oil outlet (62B / 62C / 62D), the reducer output shaft (53) is provided with an oil passage (53A), the oil outlet (62B) connects to the cavity of the reducer assembly (2), the oil outlet (62C) connects to the bearing hole of the reducer housing (62), the oil outlet (62D) connects to the oil passage (53A) of the reducer output shaft (53), the reducer housing (62) is provided with an oil return hole (62E), and the reducer output shaft (53) is provided with an oil outlet (53B) that connects to the cavity of the reducer assembly (2). The oil passage connects the oil passage of the motor assembly (1), the oil passage (62A) of the reducer housing (62), and finally connects to the inside of the reducer cavity.

[0023] The mechanical oil pump assembly (39) includes an oil pump housing (40), an oil pump cover plate (41), an inner oil pump rotor (42), and an outer oil pump rotor (43). The motor rear end cover (3) is characterized by having an oil pump mounting position (3B), the outer oil pump rotor (43) being installed inside the oil pump housing (40), the rear end of the motor shaft (32) passing through the center of the oil pump housing (40) and engaging with the center hole of the inner oil pump rotor (42), and the oil pump cover plate (41) containing an oil suction port (39A), an oil passage (39B), and an oil outlet (39C). The oil suction port (39A) extends to the lowest point of the motor oil pan (12), and the oil outlet (39C) communicates with the oil passage (3A) of the motor rear end cover (3).

[0024] The reducer housing (62) is provided with three oil outlets (62B / 62C / 62D). The first oil outlet (62B) is connected to the inner cavity of the reducer assembly (2) and is directly opposite the meshing point of the second-stage planetary gear (55) and the internal gear ring (60). The second oil outlet (62C) is connected to the bearing hole of the reducer housing (62) to lubricate the front bearing (59) of the reducer. The third oil outlet (62D) is connected to the oil passage (53A) of the reducer output shaft (53) through the oil hole (67A) provided on the cylinder liner (67). The reducer output shaft (53) is provided with an oil outlet (53B) and is directly opposite the meshing point of the motor shaft (32) and the first-stage planetary gear (54). The reducer housing (62) is provided with an oil return hole (62E) to connect the cavity between the oil seal (71), the output shaft (53), and the reducer housing (62) to the inner cavity of the reducer assembly (2).

[0025] The oil collection plate (69) has three evenly distributed oil outlets (69A). The first-stage planetary gear (54) is fixed on the second-stage planetary gear (55). The planetary gears (54 / 55) are assembled on the planetary gear pin (56) through needle roller bearings (58). The pin (56) has an oil passage (56A). The oil outlet (69A) of the oil collection plate (69) extends into the oil passage (56A) of the pin (56) and lubricates the needle roller bearing (58) through the oil outlet (56B) provided on the pin.

[0026] The front end cover (4) of the motor is provided with multiple oil return holes (4B), which connect the cavity of the reducer assembly (2) and the cavity of the motor assembly (1). The oil return holes (4B) are directly opposite the winding end of the stator assembly (15). The stator core (19) of the stator assembly (15) is provided with an oil groove (19A) on its outer periphery, which matches the inner diameter of the motor housing (5) to form an oil passage. The lower end face of the oil baffle ring (13) is provided with circumferentially distributed buckles (13A). The buckles (13A) are positioned and fixed on the groove of the inner diameter of the stator core (19). The upper end face of the oil baffle ring (13) matches and is fixed with the inner end face of the front end cover (4). The outer periphery of the motor housing (5) is provided with heat dissipation fins (5B). At least one axial oil return groove (5C) is provided on the inner circumference of the motor housing (5), which connects the upper and lower cavities of the motor assembly (1). The rear end cover (3) is provided with an oil baffle rib (3E) and two oil guide ribs (3G). The channel between the two oil guide ribs (3G) forms an oil groove (3C), which connects the inner cavity of the motor assembly (1) with the bearing hole of the rear end cover (3). The bottom of the resolver mounting position (3H) of the motor rear end cover (3) is provided with three oil return grooves (3F), which connect the bearing hole of the rear end cover (3) with the cavity of the oil pan (12). The rear end cover (3) is provided with three oil return holes (3D), which connect the cavity of the motor assembly (1) to the cavity of the oil pan (12).

[0027] The planetary carrier (51) is provided with an oil return hole (51A), which connects the reducer cavity to the reducer rear bearing hole (65) and the motor front bearing hole (33) of the motor front end cover (4). The gap between the center of the planetary carrier (51) and the motor shaft (32) connects the reducer cavity and the motor front bearing hole (65). The end face of the front dynamic balance plate (23) on the rotor assembly (24) is provided with a ramp (23A), the height of which is slightly higher than the height of the oil baffle ring (13). The front dynamic balance plate (23) is provided with a clearance groove (23B), the height of which is slightly lower than the height of the oil baffle ring (13).

[0028] The reducer assembly (2) is directly mounted on the front end of the motor assembly (1), and the two form a two-in-one electric drive system. The oil passage (3A) of the rear end cover (3), the oil passage (5A) of the housing (5), the oil passage (4A) of the front end cover (4), and the oil passage (62A) of the reducer housing (62) are connected to form the oil inlet channel of the entire system. The oil outlet (62B / 62C / 62D) of the reducer housing (62), the oil collection tray (69), the oil outlet (53B) of the output shaft (53), the oil outlet (56B) of the planetary gear pin shaft (56), the oil return hole (4B) of the front end cover (4) of the motor, the oil passage (19A) formed by the outer periphery of the stator core (19) and the housing (5), the oil return hole (3D) of the rear end cover (3), and the oil return groove (3F) are connected to form the oil return channel of the entire system. The oil inlet channel and the oil return channel of the system constitute the lubrication and cooling system of the entire two-in-one system.

[0029] The outer surface of the electric drive system assembly is provided with a heat dissipation structure, including but not limited to the heat dissipation fins (5B) provided on the outer periphery of the motor housing (5). The components that come into contact with external airflow, such as the rear end cover (3) of the motor, the oil pan (12), the rear cover plate (10) of the motor, the side cover plate (11) of the motor, the front end cover (4) of the motor, and the reducer housing (62), can all be provided with heat dissipation structures as required.

[0030] The cooling oil flow direction of the oil-air hybrid cooling rotor electric drive system is as follows: When the entire system is not in operation, the cooling oil is located in the oil storage chamber formed between the rear end cover (3) and the oil pan (12). When the motor assembly (1) starts to work, the motor shaft (32) drives the inner rotor (42) and outer rotor (43) of the mechanical oil pump (39) to rotate, and the oil pump starts to work. The oil pump (39) starts to draw oil from the cavity formed between the rear end cover (3) and the oil pan (12). The cooling oil is drawn in from the oil pump (39) suction port (39A) through the filter element (48), pumped out from the oil outlet (39C), enters the oil passage (3A) of the rear end cover (3), flows through the oil passage (5A) of the motor housing (5), the oil passage (4A) of the front end cover (4), and enters the oil passage (62A) of the reducer housing (62).

[0031] After flowing through the oil passage (62A), the cooling oil enters the reducer cavity in three separate paths. First, the cooling oil is sprayed directly from the oil outlet (62B) of the reducer housing (62) onto the meshing point of the secondary planetary gear (55) and the internal gear ring (60), lubricating them. Second, the cooling oil enters the reducer bearing hole from the oil outlet (62C) to lubricate the reducer front bearing (59). Third, the cooling oil flows from the oil outlet (62D) into the cavity between the cylinder liner (67) and the reducer housing (62), then through the oil hole (67A) on the cylinder liner (67) into the cavity between the cylinder liner (67) and the reducer output shaft (53), and finally into the reducer output shaft (53). The oil passage (53A) is finally sprayed from the oil outlet (53B) of the reducer output shaft (53) to the meshing point of the first-stage planetary gear (54) and the motor shaft (32), lubricating the first-stage planetary gear (54) and the motor shaft (32); an oil return hole (62E) is provided between the oil seal hole of the reducer housing (62) and the cavity of the reducer assembly (2), so that the cooling oil that seeps into the oil seal hole from the gap between the cylinder liner (67) and the reducer output shaft (53) and the reducer housing (62) can flow back to the cavity of the reducer assembly (2) through the oil return hole (62E), so as to prevent the oil seal (71) from being pushed out due to excessive internal pressure.

[0032] Cooling oil entering the bearing chamber from the oil outlet (62C) of the reducer housing (62) lubricates the front bearing (59) of the reducer and then enters the inner cavity of the reducer assembly. It drips onto the flange of the output shaft (53) and is thrown into the oil collection tray (69) under the action of centrifugal force. It flows into the oil passage (56A) of the planetary gear pin shaft (56) through the oil outlet (69A) on it, and then flows out from the oil outlet (56B) to lubricate the needle roller bearing (58).

[0033] The planetary carrier (51) is provided with an oil return port (51A), which is directly opposite the rear bearing (65) of the reducer. The cooling oil flows through the oil return port (51A), through the bearing (65), and then to the front bearing (33) of the motor. At the same time, the cooling oil will also directly lubricate the front bearing (33) of the motor through the gap between the center of the planetary carrier (51) and the motor shaft (32), and then enter the motor (1) cavity. After this part of the cooling oil enters the motor cavity, it drips onto the end face of the front dynamic balance plate (23) of the rotor assembly (24). The end face of the front dynamic balance plate (23) is provided with a ramp (23A). When the cooling oil passes through the ramp (23A) under the action of centrifugal force, it is forced to be thrown towards the end winding of the stator assembly (15).

[0034] Most of the cooling oil that lubricates the gear shaft of the reducer gathers in the bowl-shaped area set on the end face of the reducer side of the motor front cover (4), and enters the motor assembly (1) cavity through the multiple oil return ports (4B) set thereon. The cooling oil drips directly onto the end winding of the stator assembly (15) and carries away the heat generated by the motor during operation.

[0035] The oil baffle ring (13) is installed on the teeth of the stator core (19) via a snap fastener (13A). The lower end face mates with the end face of the stator core (19), and the upper end face mates with the end face of the motor front cover (4) and is pressed tightly. The oil baffle ring (13), the end face of the stator core (19), and the inner wall of the motor housing (5) form an annular oil storage cavity (a), in which the cooling oil entering the motor (1) cavity is collected. The upper part of the stator (15) winding is immersed in the cooling oil in the annular oil storage cavity, which increases the cooling effect of the winding at this point.

[0036] Cooling oil flows through the oil grooves provided on the outer periphery of the stator core (19) and the oil channels (19A) formed by the oil grooves on the inner wall of the motor housing (5) and the oil grooves (5C) provided on the inner wall of the housing (5), carrying away the heat on the core (19). At the same time, the heat absorbed by the cooling oil is transferred to the housing (5) when it comes into contact with the inner wall of the housing (5). In addition, the core (19) is in direct contact with the housing (5), and the heat of the core (19) can also be directly transferred to the housing (5). The outer periphery of the motor housing (5) is provided with heat dissipation fins (5B). When the external airflow passes through the heat dissipation fins (5B), it carries away the heat on them.

[0037] After the cooling oil flows through the oil passage (19A) and the housing oil groove (5C), it enters the lower cavity of the motor assembly (1). The motor rear end cover (3) is provided with an oil baffle (3E) and two oil guide ribs (3G). The oil baffle (3E) extends into the stator assembly (15) winding to a certain height. The oil baffle (3E), the inner end face of the rear end cover (3), and the inner wall of the housing (5) form an annular cavity (b). The oil needs to fill the annular cavity so that the oil level reaches a certain height of the lower end winding of the stator assembly (15), soaking the lower part of the stator assembly (15) winding, taking away the heat on it, and then overflowing from the end face of the oil baffle (3E) into the center of the rear end cover (3). The rear end cover (3) is provided with three oil return holes (3D), and the two oil guide ribs (3G) form an oil groove (3C). Cooling oil overflows through the oil baffle rib (3E), and a small portion of the cooling oil flows into the bearing hole of the rear end cover (3) through the oil groove (3C) to lubricate the rear bearing (17) of the motor. The bottom of the resolver mounting position (3H) of the rear end cover (3) is provided with three oil grooves (3F). The cooling oil flowing through the rear bearing (17) of the motor flows back to the oil pan from the oil groove (3F). Most of the remaining cooling oil that overflows through the oil baffle groove (3E) flows back to the oil pan (12) through the three oil return holes (3D).

[0038] In this embodiment, the rotor electric drive system has its own mechanical oil pump assembly (39), which forms a self-circulating lubrication and cooling system through the oil channels set inside each component. The cooling oil lubricates the gear shaft (50) of the reducer, removes the heat generated by the gear transmission, and directly contacts the winding of the stator assembly (15) and the stator core (19), thereby directly cooling the stator assembly (15). The cooling oil is in full contact with the inner wall of the motor housing (5), and the external airflow removes the heat from the heat dissipation fins (5B) on the outer periphery of the motor housing (5). The heat dissipation fins (5B) cool the circulating cooling oil. At the same time, when the external airflow contacts the outer surface of the electric drive system assembly, it also removes the heat conducted to the surface, thereby achieving oil-air mixed cooling, which effectively solves the problems of complex integrated structure and poor motor heat dissipation in large rotor electric drive systems.

[0039] Example 2 like Figure 17 As shown, in another embodiment of the present invention, an oil pump reducer gear shaft assembly (44) is assembled between the motor shaft (32) and the oil pump assembly (39). The oil pump reducer gear shaft assembly (44) includes a first-stage oil pump reduction gear (45), a second-stage oil pump reduction gear (46), and a second-stage reduction gear spindle (47). The end of the motor shaft (32) is engaged with the center hole of the first-stage oil pump reduction gear (45). The second-stage oil pump reduction gear (46) is sleeved on the second-stage reduction gear spindle (47). One end of the second-stage reduction gear spindle (47) extends into the oil pump assembly (39) and engages with the center hole of the inner rotor (42) of the oil pump.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. An oil-air hybrid cooling electric drive system, comprising an electric machine assembly and a reducer assembly, the electric machine assembly comprising an electric machine housing and a machine core assembly located in the electric machine housing, the machine core assembly comprising a stator assembly and a rotor assembly, the reducer assembly comprising a reducer housing assembled on top of the electric machine housing and a reducer internal assembly located in the reducer housing, a top end of a rotating shaft of the rotor assembly extending into the reducer housing and drivingly connected with a power input end of the reducer internal assembly, characterized in that: The bottom of the motor shell is equipped with an oil pan, and an oil pump storage cavity is formed between the bottom of the motor shell and the oil pan. An oil pump is installed in the oil pump storage cavity and at the bottom of the motor shell. The bottom end of the rotating shaft of the rotor assembly extends into the oil pump storage cavity and is drivingly connected to the power input end of the oil pump. An oil inlet channel is formed in the motor shell and the reducer shell in series. The oil outlet end of the oil pump can deliver cooling oil to the reducer shell through the oil inlet channel. The motor shell and the reducer inner shell also form an oil return channel for guiding the cooling oil flowing through the internal components of the reducer and the core assembly back to the oil pump storage cavity.

2. The oil-air hybrid cooling electric drive system of claim 1, wherein: The internal components of the reducer are planetary reduction components, and the oil inlet channel includes a main oil passage arranged on the reducer shell. The oil outlet end of the main oil passage is provided with at least two oil outlet branches, including a first oil outlet and a second oil outlet. The first oil outlet is opposite the meshing position of the planetary gear and the inner gear ring in the planetary reduction assembly for spraying cooling oil thereon. The second oil outlet is communicated to the mounting hole of the front bearing in the planetary reduction assembly.

3. The oil-air hybrid cooling electric drive system of claim 2, wherein: The oil outlet branch further includes a third oil outlet, which is communicated to an inner shaft oil passage arranged in the output shaft of the planetary reduction assembly. The outlet end of the inner shaft oil passage is opposite the meshing position of the primary planetary gear in the planetary reduction assembly and the rotating shaft in the rotor assembly for spraying cooling oil thereon.

4. The oil-air hybrid cooling electric drive system according to any one of claims 2 or 3, characterized in that: The planetary reduction assembly includes an oil collecting disc arranged on the planet carrier of the planetary reduction assembly. The oil collecting disc is provided with an oil collecting disc oil outlet. An axle shaft oil passage is arranged in the axle shaft of the planetary gear in the planetary reduction assembly. The oil collecting disc oil outlet is connected to the inlet of the axle shaft oil passage. The axle shaft oil passage is provided with an axle shaft oil outlet for lubricating the planetary gear needle bearing in the planetary reduction assembly.

5. The oil-air hybrid cooling electric drive system of claim 2, wherein: The planet carrier of the planetary reduction assembly is provided with a planet carrier oil return hole for guiding the cooling oil in the reducer shell to the rear bearing of the planetary reduction assembly. The front end of the rotor assembly is provided with a front dynamic balance plate. The end surface of the front dynamic balance plate is provided with a centrifugal flow guide structure, which is a slope surrounding the rotating shaft of the rotor assembly. The centrifugal flow guide structure is used to throw the cooling oil reaching its surface to the winding of the stator assembly under the action of centrifugal force.

6. The oil-air hybrid cooling electric drive system of claim 1, wherein: The oil return channel includes a plurality of reducer oil return holes arranged on the top of the motor shell. The reducer oil return holes are used to guide the cooling oil from the reducer shell to the upper end of the winding of the stator assembly. The outer periphery of the stator core of the stator assembly is provided with a core oil groove. The core oil groove cooperates with the inner wall of the motor shell to form a core oil passage. The core oil passage is used to guide the cooling oil to flow through the upper and lower ends of the stator core in the stator assembly for cooling.

7. The oil-air hybrid cooling electric drive system of claim 6, wherein: The oil return channel further includes at least one motor oil return groove arranged on the inner circumferential surface of the motor shell. The motor oil return groove is used to communicate the upper and lower cavities of the core assembly in the motor shell. The outer surface of at least one of the motor shell and the reducer shell is provided with a heat dissipation structure.

8. The oil-air hybrid cooling electric drive system of claim 6, wherein: The front end of the stator core in the stator assembly is provided with an oil retaining ring. The front end of the stator core in the stator assembly is formed with a front oil storage pool for collecting cooling oil and soaking part of the upper end winding in the stator assembly. The inner bottom surface of the motor housing is provided with an oil retaining rib, which is used to form a rear oil pool on the inner bottom surface of the motor housing for gathering cooling oil and soaking part of the lower end winding in the stator assembly; The oil return channel further comprises a motor oil return hole, a bearing oil guide groove and a bearing oil return groove provided on the bottom of the motor housing. The motor oil return hole is throughly provided for guiding part of the cooling oil overflowing into the inner side of the oil retaining rib into the oil pump oil storage cavity. The bearing oil guide groove is provided on the inner bottom surface of the motor housing for guiding part of the cooling oil overflowing into the inner side of the oil retaining rib to the rear bearing of the movement assembly. The bearing oil return groove is provided on the outer bottom surface of the motor housing for guiding the cooling oil flowing through the rear bearing of the movement assembly into the oil pump oil storage cavity.

9. The oil-air hybrid cooling electric drive system of claim 1, wherein: The oil pump is a rotor pump, and the bottom end of the rotating shaft of the rotor assembly is directly connected with the inner rotor center hole of the rotor pump or connected with the inner rotor of the rotor pump through an oil pump speed reducer gear shaft assembly.

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