A globally layered oil-cooled built-in permanent magnet synchronous motor

Abstract

This invention discloses a fully layered oil-cooled built-in permanent magnet synchronous motor, belonging to the field of motors. The main shaft is designed with a double-layered shaft, including multiple rectangular bellows on the oil inlet side, forming a labyrinth seal. The central rotor core is designed with an oil reservoir and radially tree-like cooling oil channels. Under oil pressure, cooling oil enters each layer of oil channels along the tree-like main channel. The cooling oil in each layer flows along an axial channel, exiting from both sides of the rotor core to the bearings at both ends. The stator core is designed with an oil reservoir and two axial oil passages. One oil passage is located at the yoke of the stator core for cooling the stator core, and the other enters the bottom of the stator core slots via a stepped oil passage for cooling the windings within the slots. Both oil passages exit from both ends of the stator core, flowing towards the ends of the stator windings. This invention shortens the heat transfer path, with each heat source having an independent direct oil path, improving the motor's heat dissipation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of motors, specifically relating to a fully layered oil-cooled built-in permanent magnet synchronous motor. Background Technology

[0002] In recent years, drive motors for new energy vehicles have been developing towards higher power density and higher torque density, making motor thermal management a key bottleneck restricting performance improvement. Oil cooling technology, due to its ability to directly contact the heat source and its significantly higher heat dissipation efficiency compared to water cooling and air cooling, has gradually become the mainstream solution.

[0003] Existing oil cooling technologies can be mainly classified into the following categories:

[0004] The first type is a combination of water cooling for the motor housing and oil spraying at the ends. This technology involves setting up a water cooling channel in the motor housing and simultaneously installing an oil spraying structure at the end cover to cool the winding ends. However, water cooling is indirect cooling, and heat must be transferred to the housing through the insulation layer and iron core, resulting in high thermal resistance and a significant temperature gradient. Furthermore, the oil spraying at the ends cannot cover the windings inside the slots, causing the slots to become the hottest points and posing a significant risk of localized overheating.

[0005] The second type is the stator core internal oil channel solution. This technology sets up axial oil channels in the yoke of the stator core, spraying oil through small holes to cool the winding ends, or guiding the cooling oil to the ends through stepped oil channels. Although this type of solution improves stator cooling, the rotor still relies on air gap heat transfer or simple hollow shaft oil slinging, resulting in insufficient cooling of the magnets and rotor core; moreover, the stator side is mostly a single-channel design, with the core and windings sharing the same oil channel, making it difficult to optimize cooling distribution.

[0006] The third category is the rotor-embedded oil circuit scheme. Some technologies set up axial oil channels in the rotor core or use balance plates to distribute cooling oil, but these are mostly simple single-layer channels with poor uniformity of cooling oil distribution; the rotor oil circuit is often independent of the stator oil circuit, lacking coordination, and the system is highly complex.

[0007] The fourth category is the oil-cooling solution for axial flux motors. For axial flux topologies, this involves a combination of end-cap rotary oil channels and inner / outer ring pressure plates with oil spraying, or supplemented by an air-oil heat exchanger to cool the rotor. However, this type of solution is only applicable to the special structure of axial flux motors and cannot be applied to mainstream radial flux motors; furthermore, the rotor is still indirectly cooled, and the thermal management problem of the magnets remains unresolved.

[0008] In summary, existing oil-cooling solutions generally suffer from the following limitations: a single cooling channel, making it impossible to achieve refined zoning management of heat sources; relatively long heat transfer paths, making it difficult to directly cool key heat sources such as in-slot windings and magnets; and a lack of coordination between the stator and rotor oil circuits, making it difficult to balance cooling efficiency and system complexity. With the further improvement of the instantaneous overload capacity and continuous power density of motors, there is an urgent need to break through the traditional "single-channel, extensive" cooling mode and achieve precise, layered, and direct cooling of the entire heat source of the motor. Summary of the Invention

[0009] To address the aforementioned technical issues, this invention provides a fully layered oil-cooled built-in permanent magnet synchronous motor. By dividing the heat source of the motor's stator and rotor into multiple independent regions and configuring a dedicated cooling channel for each region, it achieves a transformation from single-channel coarse cooling to multi-channel precise cooling, thereby shortening the heat transfer path, eliminating local hot spots, and reducing system complexity while meeting the requirements of high power density operation.

[0010] In this invention, the rotor magnets adopt a double V-shaped combined with a straight-line design, and the stator uses a multi-layer flat wire design. The main shaft is designed with a double-layer shaft; the second main shaft and the first main shaft contain multiple rectangular bellows on the oil inlet side, forming a labyrinth seal. The central rotor core is designed with an oil storage chamber and radially tree-like cooling oil channels. Under oil pressure, the cooling oil enters each layer of oil channels along the radially tree-like main channel, and the cooling oil in each layer flows along the axial channel, flowing from the outlets on both sides of the rotor core to the bearings at both ends. The stator core is designed with an oil storage chamber and two axial oil passages. One oil passage is located at the yoke of the stator core for cooling the stator core, and the other enters the bottom of the stator core slot through a stepped oil passage for cooling the windings within the slot. Both oil passages flow out from both ends of the stator core towards the ends of the stator windings. This invention shortens the heat transfer path, and each heat source has an independent direct oil passage path, improving the heat dissipation efficiency of the motor.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A fully layered oil-cooled built-in permanent magnet synchronous motor includes a stator, a main shaft, and a rotor. The main shaft includes a second main shaft and a first main shaft, with the second main shaft inserted into the interior of the first main shaft to form a first main shaft gap. Multiple rectangular bellows are arranged on the oil inlet side of the second and first main shafts to form a labyrinth seal. An oil storage chamber is provided in the middle of the rotor core, and the oil storage chamber is connected to multiple layers of axial cooling oil channels through a radial tree-like main channel. Cooling oil enters the oil storage chamber from the inner first main shaft gap through the main shaft oil inlet hole, and is distributed along the radial tree-like main channel under oil pressure. Each layer has axial cooling oil channels, with cooling oil flowing axially from both sides of the rotor core to the bearings at both ends. The stator core has an oil storage chamber and two independent axial oil passages. One axial oil passage is located at the yoke of the stator core and is used to cool the stator core. The other axial oil passage is guided to the bottom of the stator core slot through a stepped oil passage and is used to cool the windings in the slots. The two independent axial oil passages flow out from both ends of the stator core and flow to the ends of the stator windings. The rotor magnets adopt a double V-shaped combined with a straight line layout, and the stator adopts multi-layer flat wire windings.

[0013] The fully layered oil-cooled permanent magnet synchronous motor provided by this invention achieves fully layered operation, independent channels, and precise direct connection, with the following beneficial effects:

[0014] 1. This invention pioneers a layered cooling concept across the entire rotor and stator, dividing the heat source into multiple independent regions: four layers of radial tree-like cooling channels are arranged on the rotor side, each layer independently cooling a specific magnet assembly and adjacent iron core; two independent oil circuits are arranged on the stator side, precisely cooling the iron core yoke and the slot windings respectively. Each heat source region has an independent direct oil circuit path, allowing the cooling oil to directly reach the heat source surface, shortening the heat transfer path, fundamentally eliminating local hot spots caused by thermal resistance accumulation in traditional solutions, and reducing the maximum temperature rise of the motor.

[0015] 2. The rotor core of this invention has an oil storage chamber in the middle. After the cooling oil fills the oil storage chamber under oil pressure, it is evenly distributed to the four layers of rectangular oil channels along the radial tree-like main channel. This structure breaks through the limitations of traditional rotors with single channels or simple oil throwing, and realizes the three-dimensional precise distribution of cooling oil in the rotor's radial and axial directions. This improves the cooling uniformity of each layer of magnets, significantly reduces the risk of magnet demagnetization, and effectively extends the peak power duration of the motor.

[0016] 3. The stator side of this invention adopts a dual oil circuit design, combining a straight oil channel in the stator core yoke with a stepped oil channel at the bottom of the stator core slot. The stepped oil channel guides the cooling oil step-by-step through multiple small holes, directly delivering it to the bottom of the stator core slot, achieving direct cooling of the windings within the stator slots for the first time. Compared to traditional end-spraying solutions, this reduces the thermal resistance of the windings within the stator slots, slows down the insulation aging rate, and extends the motor's service life.

[0017] 4. The present invention adopts a double-layer shaft structure of a first spindle and a second spindle, and sets multiple rectangular bellows on the oil inlet side to form a labyrinth seal, which realizes reliable sealing of high-pressure cooling oil in a limited axial space. The sealing length is increased compared with the traditional single-shaft structure, the leakage risk is reduced by an order of magnitude, and the negative impact of complex sealing components on rotor dynamic performance is avoided.

[0018] 5. The rotor magnets of this invention adopt a double "V" + "I" type combined layout, with four layers of cooling channels corresponding to and matched with three sets of magnets. This satisfies the requirements of magnetic circuit design for excitation main magnetic flux, air gap magnetic flux density, sinusoidal waveform of no-load back EMF, and magnetic flux compensation, while also achieving precise coupling between the cooling oil circuit and the magnet heat source. The stator adopts multi-layer flat wire windings, which work in conjunction with the stepped slot bottom oil circuit to improve slot fill factor while ensuring heat dissipation capacity within the slots, thereby increasing the motor power density.

[0019] 6. The stator and rotor oil circuits of the present invention are integrated into the iron core body, eliminating the need for additional pipelines, joints, or complex distribution valves; four specifications of rotor iron cores and three specifications of stator iron cores can form a complete oil circuit by axial stacking, the assembly process is compatible with traditional motors, the manufacturing cost is controlled, and it has the conditions for large-scale mass production. Attached Figure Description

[0020] Figure 1This is a cross-sectional view of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0021] Figure 2 An exploded view of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0022] Figure 3 This is an exploded view of the rotor of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0023] Figure 4 This is a first cross-sectional view of the rotor of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0024] Figure 5 This is a second cross-sectional view of the rotor of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0025] Figure 6 This is a cross-sectional view of the first rotor core of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0026] Figure 7 This is a cross-sectional view of the second rotor core of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0027] Figure 8 This is a cross-sectional view of the third rotor core of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0028] Figure 9 This is a cross-sectional view of the fourth rotor core of the fully layered oil-cooled permanent magnet synchronous motor of the present invention.

[0029] Figure 10 This is another transverse cross-sectional view of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0030] Figure 11 This is an exploded view of the stator of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0031] Figure 12 This is a cross-sectional view of the stator of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0032] Figure 13 This is a cross-sectional view of the first stator core of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0033] Figure 14 This is a cross-sectional view of the second stator core of the fully layered oil-cooled permanent magnet synchronous motor of the present invention;

[0034] Figure 15 This is a cross-sectional view of the third stator core of the fully layered oil-cooled permanent magnet synchronous motor of the present invention.

[0035] In the attached drawings, the reference numerals are as follows: 1 is the drive end cover, 2 is the non-drive end cover, 3 is the current-guiding conductive brush, 4 is the rotary transformer, and 5 is the flange; 100 is the rotor, 101 is the first main shaft, 101a is the first rectangular bellows, 101b is the boss shaft, 101c is the first main shaft oil inlet, 101d is the first main shaft hollow hole, 102 is the second main shaft, 102a is the second rectangular bellows, 102b is the second main shaft hollow hole, 103 is the first bearing, 104 is the second bearing, 105 is the first skeleton oil seal, 106 is the second skeleton oil seal, 107 is the first baffle, 108 is the second baffle, 109 is the magnet, 109a is the first magnet, 109b is the second magnet, and 109c is the third magnet. 110 is the first rotor core; 110a is the oil storage chamber of the first rotor core; 110b is the teardrop-shaped hole of the first rotor core; 110c is the first rectangular hole of the first rotor core; 110d is the second rectangular hole of the first rotor core; 110e is the third rectangular hole of the first rotor core; 110f is the fourth rectangular hole of the first rotor core; 110g is the fifth rectangular hole of the first rotor core; 110h is the first magnet slot of the first rotor core; 110i is the second magnet slot of the first rotor core; 110j is the third magnet slot of the first rotor core; 120 is the second rotor core; 120a is the first rectangular hole of the second rotor core; 120b is the second rectangular hole of the second rotor core; 120c is the second rotor core. The third rectangular hole; 120d is the fourth rectangular hole of the second rotor core; 120e is the fifth rectangular hole of the second rotor core; 130 is the third rotor core; 130a is the first rectangular hole of the third rotor core; 130b is the second rectangular hole of the third rotor core; 130c is the third rectangular hole of the third rotor core; 130d is the fourth rectangular hole of the third rotor core; 130e is the fifth rectangular hole of the third rotor core; 130f is the sixth rectangular hole of the third rotor core; 140 is the fourth rotor core; 140a is the first rectangular hole of the fourth rotor core; 140b is the second rectangular hole of the fourth rotor core; 140c is the third rectangular hole of the fourth rotor core; 140d is the fourth rectangular hole of the fourth rotor core. Small holes: 140e is the fifth rectangular small hole of the fourth rotor core; 150 is the fifth rotor core; 160 is the sixth rotor core; 170 is the seventh rotor core; 200 is the stator; 201 is the housing; 201a is the oil inlet; 202 is the stator winding; 210 is the first stator core; 210a is the oil storage chamber of the first stator core; 210b is the teardrop-shaped small hole of the first stator core; 220 is the second stator core; 220a is the rectangular small hole of the second stator core; 220b is the teardrop-shaped small hole of the second stator core; 230 is the third stator core; 230a is the first rectangular small hole of the third stator core; 230b is the second rectangular small hole of the third stator core; 240 is the fourth stator core; 250 is the fifth stator core. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0037] This invention provides a fully layered oil-cooled built-in permanent magnet synchronous motor, consisting of a stator, rotor, and main shaft. It features a 54-slot, 6-pole configuration, with the rotor magnets arranged in a double-V-shape combined with a straight-line configuration. The stator employs a multi-layered flat wire design. The main shaft is designed as a double-layered structure, including an outer first main shaft and an inner second main shaft. The second main shaft is inserted into the cavity of the first main shaft. The second and first main shafts have multiple rectangular bellows on their oil inlet sides, forming a labyrinth seal to increase the difficulty of cooling oil leakage. The central rotor core is designed with an oil reservoir and radially tree-like cooling oil channels. Cooling oil enters from the second main shaft, then flows back into the gap between the second and first main shafts, first entering the oil reservoir in the middle of the rotor core. Under oil pressure, the cooling oil enters the rectangular oil channels of each layer along the radially tree-like main channel. The cooling oil in each layer flows along the axial channel, exiting from the outlets on both sides of the rotor core towards the bearings at both ends. The stator core is designed with an oil reservoir and two axial oil passages. Cooling oil enters from the middle of the housing. One oil passage is located at the yoke of the stator core and flows axially to cool the stator core. The other oil passage enters the bottom of the stator core slots through a stepped oil passage and flows axially to cool the windings within the slots. The two axial oil passages exit from both ends of the stator core and flow towards the ends of the stator windings.

[0038] Specifically, such as Figure 1 As shown, the fully layered oil-cooled built-in permanent magnet synchronous motor of the present invention consists of a stator 200 and a rotor 100. The rotor 100 is located inside the cavity of the stator 200, forming an inner rotor radial flux permanent magnet synchronous motor with 54 slots and 6 poles. The magnets 109 of the rotor 100 are arranged in a double V-shape combined with a straight line. The double V-shaped magnets of the magnets 109 consist of two sets of magnets with different included angles and different specifications, and straight line magnets. The straight line magnets are located on top of the double V-shaped magnets. The stator winding 202 of the stator 200 adopts a multi-layer flat wire design.

[0039] like Figure 2As shown, the rotor 100 is inserted into the cavity of the stator 200. The rotor 100 has a second bearing 104 at the driving end and a first bearing 103 at the non-driving end. The second bearing 104 is located in the bearing housing of the driving end cover 1; the first bearing 103 is located in the bearing housing of the non-driving end cover 2. The two bearings provide support for the rotor 100. A current-guiding conductive brush 3 is provided inside the cavity of the non-driving end cover 2. The current-guiding conductive brush 3 is fitted onto the non-driving end side of the rotor 100, located outside the first bearing 103, and is used to bypass the shaft current. A rotary transformer 4 is installed outside the current-guiding conductive brush 3 and is used to detect the rotor position. A flange 5 is fixed to the non-driving end cover 2.

[0040] like Figures 3-5 As shown, in order to deliver the cooling oil into the rotor core in layers, the present invention provides four types of rotor cores, namely the first rotor core 110, the second rotor core 120 and the fifth rotor core 150 (of the same specification), the third rotor core 130 and the sixth rotor core 160 (of the same specification), and the fourth rotor core 140 and the seventh rotor core 170 (of the same specification).

[0041] like Figure 3 As shown, the first rotor core 110 is located in the middle of the rotor 100. From the middle position to the drive end, the second rotor core 120, the third rotor core 130, and the fourth rotor core 140 are placed sequentially; similarly, from the middle to the non-drive end, the fifth rotor core 150, the sixth rotor core 160, and the seventh rotor core 170 are placed sequentially. The first baffle 107 on the drive end and the second baffle 108 on the non-drive end are fitted onto the first main shaft 101 to press the rotor cores together for dynamic balancing. The first skeleton oil seal 105 on the drive end is fitted onto the first main shaft 101 and is located outside the second bearing 104; the second skeleton oil seal 106 on the non-drive end is fitted onto the first main shaft 101 and is located outside the first bearing 103. Each magnetic pole is represented by a magnet 109, which consists of a first magnet 109a, a second magnet 109b, and a third magnet 109c. The first magnet 109a of each magnetic pole consists of two V-shaped magnets, providing the main magnetic flux of each pole. The second magnet 109b of each magnetic pole consists of two V-shaped magnets, used to adjust the sinusoidal waveform of the air gap magnetic flux density. The third magnet 109c is located on top of the second magnet 109b, used to supplement and enhance the main magnetic flux of each pole.

[0042] like Figure 3 , Figure 6As shown, the first magnet 109a is inserted into the first magnet slot 110h of the first rotor core, the second magnet 109b is inserted into the second magnet slot 110i of the first rotor core, and the third magnet 109c is inserted into the third magnet slot 110j of the first rotor core; similarly, the axial segments of the magnet 109 are respectively embedded into the magnet slots corresponding to the second rotor core 120 to the seventh rotor core 170.

[0043] like Figures 3-5 As shown, the spindle design has a double-layer spindle, including a first spindle 101 and a second spindle 102.

[0044] The second spindle 102 is inserted into the cavity of the first spindle 101. The first spindle 101 and the second spindle 102 each contain a first rectangular bellows 101a and a second rectangular bellows 102a on their oil inlet sides. These two sets of rectangular bellows form a long labyrinth seal, increasing the resistance to cooling oil leakage and ensuring that most of the cooling oil passes through the first spindle oil inlet hole 101c. One end of the second spindle 102 of the rotor 100 is fixed to the flange 5, and the other end forms a sliding bearing support with the boss shaft 101b inside the cavity of the first spindle 101.

[0045] like Figure 4 As shown, the dashed line with arrows indicates the first flow path of the cooling oil, which flows in a stepped shape along the axial direction to the side end face of the rotor 100, i.e.:

[0046] Cooling oil → oil pump → oil inlet in the hollow hole 102b of the second spindle → hollow hole 101d of the first spindle → small oil inlet hole 101c of the first spindle → first rotor core 110 → oil storage chamber 110a and teardrop-shaped small hole 110b of the first rotor core → second rotor core 120 → first rectangular small hole 120a of the second rotor core → third rotor core 130 → sixth rectangular small hole 130f of the third rotor core → fourth rotor core 140 → fourth rectangular small hole 140d of the fourth rotor core → second bearing 104.

[0047] like Figure 5As shown, the dashed line with arrows indicates the second flow path of the cooling oil. In the radial direction, each oil trough is first filled along the radially tree-like cooling channels, and then flows along the axial channels of each rotor core segment to the side end face of rotor 100, i.e.: Cooling oil → Oil pump → Oil inlet of the second spindle hollow hole 102b → First spindle hollow hole 101d → First spindle oil inlet hole 101c → First rotor core 110 → First rotor core oil storage chamber 110a and first rotor core teardrop-shaped hole 110b → First rotor core third rectangular hole 110e → First rotor core second rectangular hole 110d → First rotor core fourth rectangular hole 110f → First rotor core fifth rectangular hole 110g → Second rotor core 120 → Second rotor core first rectangular hole 120a → Second rotor core third rectangular hole 120c → Second rotor core fourth rectangular hole 120d → Second rotor core fifth rectangular hole 120e → Third rotor core 130 → Third rotor core first rectangular hole 130a → Third rotor core third rectangular hole 130c → Third rotor core fourth rectangular hole 130d → Third rotor core fifth rectangular hole 130e → Fourth rotor core 140 → Fourth rotor core first rectangular hole 140a → Fourth rotor core third rectangular hole 140c → Fourth rotor core fourth rectangular hole 140d → Fourth rotor core fifth rectangular hole 140e.

[0048] Preferably, the first rectangular hole 110c of the first rotor core, the second rectangular hole 120b of the second rotor core, the second rectangular hole 130b of the third rotor core, and the second rectangular hole 140b of the fourth rotor core are magnetically shielding rectangular holes. The flow sequence is: second rotor core 120 → second rotor core first rectangular hole 120a → third rotor core 130 → third rotor core sixth rectangular hole 130f → fourth rotor core 140 → fourth rotor core fourth rectangular hole 140d → second bearing 104.

[0049] Preferably, the oil circuit layout from the first rotor core 110 to the drive end side is the same as the oil circuit layout from the first rotor core 110 to the non-drive end side.

[0050] like Figure 6 As shown, a first rotor core oil storage chamber 110a is provided between the first rotor core 110 and the first main shaft 101, and a first rotor core teardrop-shaped small hole 110b is provided on the inner circle of the first rotor core 110, which is connected to the first rotor core oil storage chamber 110a.

[0051] A first rectangular hole 110c is provided in the first rotor core to reduce the leakage flux of the third magnet 109c. A second rectangular hole 110d in the first rotor core is located between the second magnet 109b and the third magnet 109c. The third rectangular hole 110e of the first rotor core serves as the main diameter of the radial path of the tree-like cooling channel. It connects and links the teardrop-shaped hole 110b of the first rotor core (the diameter range of the oil storage cavity 110a and the teardrop-shaped hole 110b of the first rotor core constitutes the first layer of cooling channel), the second rectangular hole 110d of the first rotor core (the diameter range of the second rectangular hole 110d of the first rotor core constitutes the second layer of cooling channel), the fourth rectangular hole 110f of the first rotor core (the diameter range of the fourth rectangular hole 110f of the first rotor core constitutes the third layer of cooling channel), and the fifth rectangular hole 110g of the first rotor core (the fifth rectangular hole 110g of the first rotor core is located at the end of the tree-like cooling channel, and its diameter range constitutes the fourth layer of cooling channel), for a total of four layers of rectangular holes, which ultimately connect to the oil storage cavity 110a of the first rotor core.

[0052] like Figure 7 As shown, the second rotor core 120 includes multiple layers of stepped holes, wherein the first rectangular hole 120a of the second rotor core is axially connected to the teardrop-shaped hole 110b of the first rotor core, the second rectangular hole 120b of the second rotor core is axially connected to the first rectangular hole 110c of the first rotor core, the third rectangular hole 120c of the second rotor core is axially connected to the second rectangular hole 110d of the first rotor core, the fourth rectangular hole 120d of the second rotor core is axially connected to the fourth rectangular hole 110f of the first rotor core, and the fifth rectangular hole 120e of the second rotor core is axially connected to the fifth rectangular hole 110g of the first rotor core.

[0053] The second rotor core 120 and the fifth rotor core 150 are distributed symmetrically on both sides of the first rotor core 110.

[0054] like Figure 8 As shown, the third rotor core 130 includes multiple layers of stepped holes. Among them, the first rectangular hole 130a, the first rectangular hole 120a, and the sixth rectangular hole 130f of the third rotor core are axially connected. The second rectangular hole 130b and the second rectangular hole 120b of the third rotor core are axially connected. The third rectangular hole 130c and the third rectangular hole 120c of the third rotor core are axially connected. The fourth rectangular hole 130d and the fourth rectangular hole 120d of the third rotor core are axially connected. The fifth rectangular hole 130e and the fifth rectangular hole 120e of the third rotor core are axially connected.

[0055] The third rotor core 130 and the sixth rotor core 160 are distributed symmetrically on both sides of the first rotor core 110.

[0056] like Figure 9 As shown, the fourth rotor core 140 includes multiple layers of stepped holes, wherein the first rectangular hole 140a of the fourth rotor core is axially connected to the first rectangular hole 130a of the third rotor core, the second rectangular hole 140b of the fourth rotor core is axially connected to the second rectangular hole 130b of the third rotor core, the third rectangular hole 140c of the fourth rotor core is axially connected to the third rectangular hole 130c of the third rotor core, the fourth rectangular hole 140d of the fourth rotor core is axially connected to the fourth rectangular hole 130d of the third rotor core, and the fifth rectangular hole 140e of the fourth rotor core is axially connected to the fifth rectangular hole 130e of the third rotor core.

[0057] The fourth rotor core 140 and the seventh rotor core 170 are distributed on both sides of the first rotor core 110, forming a symmetrical distribution.

[0058] like Figure 10 As shown, the magnets 109 of the rotor 100 are arranged in a double V-shape combined with a straight line. The first V-shaped magnets, namely the first magnet 109a, mainly provide the main excitation flux. The second V-shaped magnets, namely the second magnet 109b, mainly improve the air gap magnetic flux waveform. The straight line third magnet 109c mainly compensates for the main excitation flux.

[0059] The radial tree-like cooling oil channels of the first rotor core 110 enter the interior of the rotor core, while the axial stepped cooling oil channels are responsible for cooling each magnet 109 and the rotor core itself. The design of the first rotor core oil reservoir 110a facilitates the filling of the reservoir under oil pressure, thereby uniformly entering each tree-like cooling channel.

[0060] like Figure 11 , Figure 12 As shown, the stator core design has three specifications: the first stator core 210, the second stator core 220 and the fourth stator core 240, and the third stator core 230 and the fifth stator core 250. The stator winding 202 adopts a multi-layer flat wire design.

[0061] The first stator core 210 is located in the middle of the stator core, and the second stator core 220 and the fourth stator core 240 are symmetrically distributed on both sides of the first stator core 210. The third stator core 230 and the fifth stator core 250 are symmetrically distributed on the outermost side of the first stator core 210, and their corresponding oil circuit designs are also the same.

[0062] like Figure 13As shown, the first stator core 210 has a teardrop-shaped hole 210b in the yoke, and an oil storage cavity 210a is formed between the first stator core 210 and the housing 201.

[0063] like Figure 14 As shown, the second stator core 220 has a rectangular hole 220a (the diameter range of the rectangular hole 220a belongs to the fifth cooling channel) and a teardrop-shaped hole 220b (the diameter range of the teardrop-shaped hole 220b belongs to the sixth cooling channel) on its yoke. The hole layout of the fourth stator core 240 is the same as that of the second stator core 220.

[0064] like Figure 15 As shown, the third stator core 230 has a first rectangular hole 230a in the yoke and a second rectangular hole 230b in the stator slot (the diameter range of the second rectangular hole 230b belongs to the seventh cooling channel). The hole layout of the fifth stator core 250 is the same as that of the third stator core 230.

[0065] The stator core is divided into five specifications along the axial direction: the first stator core 210, the second stator core 220, the third stator core 230, the fourth stator core 240, and the fifth stator core 250. The fifth, sixth, and seventh cooling channels are all located in the yoke of the stator core.

[0066] like Figure 11 As shown, the dashed lines with arrows indicate the direction of oil flow. Figures 13-15 This indicates the oil flow direction for each section of the stator core. The layered oil circuit design of stator 200 is as follows:

[0067] The first stator core 210 is provided with a first stator core oil storage chamber 210a. Cooling oil enters from the middle of the housing 201 and first fills the first stator core oil storage chamber 210a. The stator 200 is designed with two axial oil passages. The first oil passage passes through the second stator core 220 and the third stator core 230 to the drive end, and passes through the fourth stator core 240 and the fifth stator core 250 to the non-drive end, and is used to cool the yoke of the stator core. The second oil passage passes through a stepped oil passage, passing through the teardrop-shaped holes 210b and 220b of the first stator core in sequence, and enters the bottom position of the slot of the fourth stator core 240, and is used to cool the part inside the slot of the stator winding 202, delivering the cooling oil to the part inside the slot of the stator winding 202. Two oil channels flow out from the outside of the fourth stator core 240 and the fifth stator core 250, and flow to the end part of the stator winding 202, so as to achieve the effect of directly cooling the end winding of the stator.

[0068] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fully layered oil-cooled built-in permanent magnet synchronous motor, characterized in that: The system includes a stator, a main shaft, and a rotor. The main shaft comprises a second main shaft and a first main shaft, with the second main shaft inserted into the interior of the first main shaft to form a gap between them. Multiple rectangular bellows are installed on the oil inlet side of the second and first main shafts to form a labyrinth seal. An oil storage chamber is located in the center of the rotor core. This chamber is connected to multiple layers of axial cooling oil channels via a radially tree-like main channel. Cooling oil enters the oil storage chamber from the inner first main shaft gap through the main shaft oil inlet and, under oil pressure, is distributed to each layer of axial cooling oil channels along the radially tree-like main channel. Each layer of cooling oil flows axially and exits from both sides of the rotor core to the bearings at both ends; the stator core is equipped with an oil storage chamber and two independent axial oil passages. One axial oil passage is located at the yoke of the stator core and is used to cool the stator core. The other axial oil passage is guided to the bottom of the stator core slot through a stepped oil passage and is used to cool the windings in the slots. The two independent axial oil passages flow out from both ends of the stator core and flow to the ends of the stator windings; the rotor magnets adopt a double V-shaped combined with a straight-line magnet, and the stator adopts a multi-layer flat wire winding.

2. The fully layered oil-cooled built-in permanent magnet synchronous motor according to claim 1, characterized in that: The rotor core consists of four types of cores, including a first rotor core located in the middle and a second, third and fourth rotor cores symmetrically distributed on both sides of it. Each rotor core is axially stacked to form a complete oil circuit.

3. The fully layered oil-cooled built-in permanent magnet synchronous motor according to claim 2, characterized in that: In the double-V-shaped combined with the straight-line magnet, two first magnets and two second magnets form a double-V shape. The first magnets are used to provide the main excitation flux, the second magnets are used to improve the air gap magnetic flux waveform, and the third magnet is straight-lined and located at the top of the V-shape formed by the two second magnets, and is used to compensate for the main excitation flux.

4. The fully layered oil-cooled built-in permanent magnet synchronous motor according to claim 2, characterized in that: The second, third, and fourth rotor cores each contain multiple layers of stepped holes, and each layer of stepped holes is axially connected to the corresponding stepped holes of the adjacent rotor cores to form a continuous axial cooling oil channel.

5. The fully layered oil-cooled built-in permanent magnet synchronous motor according to claim 1, characterized in that: The stator core consists of three types of cores, including a first stator core, a second stator core, and a third stator core. An oil storage cavity is formed between the first stator core and the housing. Each stator core is axially stacked to form a complete oil circuit.

6. A fully layered oil-cooled built-in permanent magnet synchronous motor according to claim 5, characterized in that: The first stator core has a teardrop-shaped hole in the yoke, the second stator core has a rectangular hole and a teardrop-shaped hole in the yoke, and the third stator core has a first rectangular hole in the yoke and a second rectangular hole at the bottom of the stator slot.

7. A fully layered oil-cooled built-in permanent magnet synchronous motor according to claim 3, characterized in that: The first rotor core has a teardrop-shaped hole on its inner circle that connects to the oil storage cavity, and four rectangular holes that form four cooling channels. The first rectangular hole is located outside the third magnet to reduce magnetic leakage, the second rectangular hole is located between the second and third magnets, and the third rectangular hole serves as a radial tree-like main channel connecting the cooling channels.

8. The fully layered oil-cooled built-in permanent magnet synchronous motor according to claim 1, characterized in that: The second spindle is provided with a boss shaft, one end of the first spindle is fixed to the flange, and the other end forms a sliding bearing support with the boss shaft.

9. A fully layered oil-cooled built-in permanent magnet synchronous motor according to claim 1, characterized in that: The rotor core is provided with baffles on both sides.

10. A fully layered oil-cooled built-in permanent magnet synchronous motor according to claim 9, characterized in that: The baffle is fitted onto the main shaft to press the rotor core.

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