A motor rotor cooling structure and a motor

Abstract

The present invention discloses a motor rotor cooling structure and a motor. The motor rotor cooling structure includes a front-end drive structure, a rotor self-driven heat dissipation structure, and a rear-end drive structure, and the three rotate together with the rotating shaft. The front-end drive structure includes a first-stage pressurization part for rotor core cooling, a second-stage drainage part for rotor core cooling, and a fourth-stage pressure relief flow channel for pole cooling. The rotor self-driven heat dissipation structure includes a rotor core, poles and a sheath fixed outside the rotor core. A third-stage ventilation self-driven flow channel for rotor core cooling is provided at the rotor core, and a third-stage back-gap self-driven flow channel for pole cooling is provided near the bottom of the poles. The rear-end drive structure includes a first-stage pressurization part for pole cooling, a second-stage drainage part for pole cooling, and a fourth-stage pressure relief flow channel for rotor core. Through the design of counter-directional pressurization blades and twisted flow channels in the inner and outer layers, the present invention breaks through the one-way flow limitation, realizes the Coanda effect self-compensation of air flow, and achieves the counter-directional double-layer strong cooling of the poles and the rotor core.

Description

Technical Field

[0001] The present invention relates to an air-cooled radial flux high-speed motor, and particularly to a motor rotor cooling structure and a motor. Background Art

[0002] Due to its compact structure and high power density characteristics, air-cooled radial flux high-speed motors have shown significant advantages in fields such as new energy vehicle drive and aerospace propulsion. To meet the demand for power density improvement in ultra-high speed scenarios, the trend of developing towards smaller volume and higher efficiency is irreversible. However, with the synchronous increase of rotor speed and electromagnetic load, the eddy current losses of the rotor permanent magnet and the sheath increase non-linearly, resulting in local temperature rise exceeding the material temperature resistance limit, seriously threatening the reliability of the motor. Existing cooling technologies mostly focus on optimizing heat dissipation on the stator side (such as liquid-cooled housing, phase change material filling), while in the rotor region, due to the problems of rotary sealing and centrifugal force limitation, long-term reliance on gas self-cooling, the problem of insufficient heat dissipation efficiency has become the core bottleneck restricting the performance leap of the motor.

[0003] Currently, the technical routes for rotor cooling are mainly divided into two categories:

[0004] External enhanced air cooling: By optimizing the end fan blades (such as diagonal flow type, centrifugal type) to increase the air gap flow rate, but at high speeds, the mechanical losses generated by the coaxially installed fans account for a large proportion, and uneven air flow distribution easily leads to a relatively high axial temperature gradient.

[0005] Internal indirect liquid cooling: Adopting hollow shaft internal circulation oil cooling or micro-channel design inside the permanent magnet, although it can reduce the hot spot temperature, the introduction of rotary joints and sealing structures increases the system complexity sharply, and the mechanical failure rate is relatively high.

[0006] In addition to the above problems, the existing rotor cooling technologies also have the following main defects:

[0007] First: Uneven air flow distribution and secondary flow loss.

[0008] Traditional rotor cooling schemes (such as core forced air cooling, finned sheath surface) rely on single-direction air flow, resulting in a relatively high axial temperature gradient, and at high speeds, the Coandă effect offset caused by centrifugal force forms a local overheating area (the temperature at the edge of the permanent magnet is higher than the center temperature).

[0009] Existing jet port designs (such as the utility model patent 202123143489.2) only achieve unidirectional pressurization, unable to offset the radial pressure imbalance caused by centrifugal force, and the secondary flow loss accounts for a relatively large proportion in the total power consumption.

[0010] Second: The material properties cannot solve the problem of thermal stress concentration.

[0011] The internal flow channels of the surface-mounted rotor core are mostly straight or simple arcs, which cannot adapt to the dynamic deformation caused by centrifugal force, resulting in microcracks at the interface between the flow channel and the permanent magnet.

[0012] The depth of the gas groove at the bottom of the traditional magnetic pole is insufficient, which cannot effectively reduce the eddy current loss in the back gap of the permanent magnet, and also cannot effectively dissipate heat in the back gap of the permanent magnet.

[0013] Third: The contradiction between cooling efficiency and system complexity.

[0014] Oil immersion cooling requires a rotating seal (with a certain leakage rate), and the viscous loss of the oil will reduce the overall efficiency of the motor.

[0015] Phase change cooling (such as microchannel heat pipes) can reduce the hot spot temperature, but it will introduce the problem of controlling the working fluid filling rate (a deviation in the optimal filling rate will cause a large fluctuation in the heat transfer performance). Summary of the Invention

[0016] The purpose of the present invention is to provide a motor rotor cooling structure and a motor, which can at least solve one of the technical problems in the related technologies to a certain extent.

[0017] To achieve the above invention purpose, the present invention adopts the following technical solutions:

[0018] A motor rotor cooling structure includes a rotating shaft, on which a front-end driving structure, a middle rotor self-driven heat dissipation structure, and a rear-end driving structure are sequentially and fixedly arranged along the axial direction. The three rotate together with the rotating shaft;

[0019] The front-end driving structure includes a first-stage pressurization part for rotor core cooling, a second-stage drainage part for rotor core cooling, and a fourth-stage pressure relief flow channel for magnetic pole cooling;

[0020] The rotor self-driven heat dissipation structure includes a rotor core, a magnetic pole and a sheath fixed outside the rotor core. A third-stage ventilation self-driven flow channel for rotor core cooling is provided at the rotor core, and a third-stage back-gap self-driven flow channel for magnetic pole cooling is provided near the bottom of the magnetic pole;

[0021] The rear-end driving structure includes a first-stage pressurization part for magnetic pole cooling, a second-stage drainage part for magnetic pole cooling, and a fourth-stage pressure relief flow channel for rotor core;

[0022] The first-stage pressurization part for rotor core cooling, the second-stage drainage part for rotor core cooling, the third-stage ventilation self-driven flow channel for rotor core cooling, and the fourth-stage pressure relief flow channel for rotor core are sequentially connected, and the gas flow direction is from front to back;

[0023] The first-stage pressurization part for magnetic pole cooling, the second-stage drainage part for magnetic pole cooling, the third-stage back-gap self-driven flow channel for magnetic pole cooling, and the fourth-stage pressure relief flow channel for magnetic pole cooling are sequentially connected, and the gas flow direction is from back to front.

[0024] Further, the first-stage pressurization part of the rotor core cooling includes a front hub and a front rim arranged in concentric circles. There are front blades between the front hub and the front rim. A front tapered flow channel is provided at the rear position of the front rim. The inner diameter of the front tapered flow channel gradually decreases from front to back, and a front pressurization spray ring is formed between the small-diameter section of the front tapered flow channel and the front hub.

[0025] Further, the second-stage drainage part of the rotor core cooling includes a front gas main input channel and a front airfoil curved wall flow channel;

[0026] There is a radial gap between the front hub and the rotating shaft, forming a front gas main input channel;

[0027] The front tapered flow channel is connected to the front airfoil curved wall flow channel at the rear. The high-speed gas ejected from the front pressurization spray ring sprays at the front airfoil curved wall flow channel;

[0028] The front gas main input channel is connected to the front end of the front airfoil curved wall flow channel, and the rear end of the front airfoil curved wall flow channel is connected to the front end of the third-stage ventilation self-driven flow channel of the rotor core cooling.

[0029] Further, the fourth-stage pressure relief flow channel of the pole cooling is located radially outside the front airfoil curved wall flow channel. The overall fourth-stage pressure relief flow channel of the pole cooling is gradually expanding along the gas flow direction;

[0030] There is an axial gap between the front end of the fourth-stage pressure relief flow channel of the pole cooling and the front rim, and it cooperates with the outer wall surface of the front tapered flow channel to form a wall surface gas outlet. The wall surface gas outlet corresponds to the end of the stator winding at the front end;

[0031] The rear end of the fourth-stage pressure relief flow channel of the pole cooling is connected to the front end of the third-stage back-gap self-driven flow channel of the pole cooling.

[0032] Further, the first-stage pressurization part of the pole cooling includes a rear hub and a rear rim arranged in concentric circles. There are rear blades between the rear hub and the rear rim. The rear rim is connected to a rear tapered flow channel at the front. The inner diameter of the rear tapered flow channel gradually decreases from back to front, and a rear pressurization spray ring is formed between the small-diameter section of the rear tapered flow channel and the rear hub.

[0033] Further, the second-stage drainage part of the pole cooling includes a rear airfoil curved wall flow channel;

[0034] A rear airfoil curved wall flow channel is provided at the front position of the rear tapered flow channel. The high-speed gas ejected from the rear pressurization spray ring sprays at the rear airfoil curved wall flow channel; the front end of the rear airfoil curved wall flow channel is connected to the third-stage back-gap self-driven flow channel of the pole cooling;

[0035] There is an axial gap between the rear end of the rear wing airfoil curved wall flow channel and the rear rim, and it cooperates with the outer wall surface of the rear tapered flow channel to form a wall surface gas inlet, and the wall surface gas inlet corresponds to the end of the stator winding at the rear end.

[0036] Furthermore, the rotor core cooling four-stage pressure relief flow channel is located radially inside the rear hub and has a radial gap with the rotating shaft. The rotor core cooling four-stage pressure relief flow channel is tapered as a whole along the gas flow direction;

[0037] The front end of the rotor core cooling four-stage pressure relief flow channel is connected to the rear end of the rotor core cooling three-stage ventilation self-driven flow channel, and the rear end of the rotor core cooling four-stage pressure relief flow channel extends to be basically flush with the rear end of the rear hub.

[0038] Furthermore, each component of the front-end drive structure / rear-end drive structure is connected by circumferentially distributed support columns between the radial directions and between the front-end drive structure / rear-end drive structure and the rotating shaft, and the support columns have a diamond cross-section.

[0039] Furthermore, the rotor core is divided into multiple core segments, and each core segment is laminated with silicon steel sheet punchings at different angles, so that the rotor core cooling three-stage ventilation self-driven flow channel / pole cooling three-stage back-gap self-driven flow channel is at a certain misalignment angle with the axial direction to generate an axial thrust on the gas.

[0040] The present invention also discloses a motor, including the motor rotor cooling structure. The motor rotor cooling structure is located inside the machine base. The machine base includes a machine shell, a front end cover and a rear end cover. The front-end drive structure is close to the front end cover, the rear-end drive structure is close to the rear end cover, and the outer sides of the machine shell, the front end cover and the rear end cover all have heat dissipation structures.

[0041] The beneficial effects of the present invention are:

[0042] 1. Through the design of the opposing pressurizing blades and the twisted flow channels on the inner and outer layers, the present invention breaks through the one-way flow limitation, realizes the Coandă effect self-compensation of the air flow, and realizes the opposing double-layer strong cooling of the magnetic poles and the rotor core.

[0043] 2. By using the special-shaped topology of the back-gap groove at the bottom of the magnetic pole (the pole cooling three-stage back-gap self-driven flow channel), the present invention synchronously reduces the eddy current loss and the stress concentration coefficient of the magnetic poles and the rotor core, solves the coupling contradiction of decoupling heat - electricity - force, and synchronously reduces the eddy current loss and the stress concentration coefficient.

[0044] 3. The present invention constructs a fully autonomous heat dissipation system: the inlet and outlet flow channels not only realize gas cooling by coupling with the internal flow channels of the rotor through the heat conduction structure of the end cover, but also can accelerate the flow of the end of the stator winding to improve the heat dissipation capacity of this part. At the same time, the external oil pump / fan is cancelled to improve the reliability of the system. Description of the Drawings

[0045] Figure 1 It is the overall schematic diagram of the present invention;

[0046] Figure 2 It is the schematic diagram of the front-end drive structure in the present invention;

[0047] Figure 3 It is the schematic diagram of the rear-end drive structure in the present invention;

[0048] Figure 4 It is the schematic diagram of the rotor self-driven heat dissipation structure in the present invention;

[0049] Figure 5 is Figure 4 side view of;

[0050] Figure 6 It is the schematic diagram of the layer-by-layer disassembly of the rotor self-driven heat dissipation structure in the present invention;

[0051] Figure 7 It is the schematic diagram of the internal flow heat dissipation of the motor in the present invention.

[0052] The attached drawings are only for illustrative purposes and should not be construed as a limitation to this application; for better illustration of this embodiment, some components in the attached drawings may be omitted, enlarged or reduced, which do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the attached drawings may be omitted. Specific embodiments

[0053] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the attached drawings in the embodiments of the present invention.

[0054] Embodiment 1:

[0055] As Figures 1 to 7 shown, this embodiment discloses a motor rotor cooling structure, which includes a rotating shaft 6. Along the axial direction of the rotating shaft 6, there are successively arranged a front-end drive structure 1, a middle rotor self-driven heat dissipation structure 3, and a rear-end drive structure 2. The front-end drive structure 1, the rear-end drive structure 2, and the rotor self-driven heat dissipation structure 3 are the main design parts of the motor rotor cooling structure, and the three are fixed on the rotating shaft 6 and rotate together with the rotating shaft 6.

[0056] The front-end drive structure includes a first-stage pressurization part 110 for rotor core cooling, a second-stage drainage part 111 for rotor core cooling, and a fourth-stage pressure relief flow channel 113 for pole cooling. The front-end drive structure is close to the front end cover 10 of the motor and is fixed on the rotating shaft 6, and is used for the gas flow circulation at the front end of the rotor self-driven heat dissipation structure 3.

[0057] The rotor self-driven cooling structure includes a rotor core and magnetic poles 4. The magnetic poles 4 are fixed on the rotor core, and the outer side is reinforced with a sheath 5 to form a surface-mounted rotor. A three-stage ventilation self-driven flow channel 31 for rotor core cooling is provided at the middle position of the rotor core, and a three-stage back-gap self-driven flow channel 32 for magnetic pole cooling is provided near the magnetic poles on the outer side of the rotor core.

[0058] The rear-end drive structure 2 includes a first-stage boosting part 210 for magnetic pole cooling, a second-stage diversion part 211 for magnetic pole cooling, and a four-stage pressure-relief flow channel 213 for the rotor core. The rear-end drive structure 2 is close to the motor rear-end cover 11 and fixed on the rotating shaft 6, and is used for the gas flow circulation at the rear end of the rotor self-driven cooling structure 3.

[0059] The first-stage boosting part 110 for rotor core cooling, the second-stage diversion part 111 for rotor core cooling, the three-stage ventilation self-driven flow channel 31 for rotor core cooling, and the four-stage pressure-relief flow channel 213 for the rotor core are connected, and the gas flow direction is from front to back. This part of the air path is mainly used to cool the rotor core.

[0060] The first-stage boosting part 210 for magnetic pole cooling, the second-stage diversion part 211 for magnetic pole cooling, the three-stage back-gap self-driven flow channel 32 for magnetic pole cooling, and the four-stage pressure-relief flow channel 113 for magnetic pole cooling are connected, and the gas flow direction is from back to front. This part of the air path is mainly used to cool the magnetic poles.

[0061] The specific settings of the above structures are described in detail below.

[0062] As Figure 2 shown, the first-stage boosting part for rotor core cooling includes a front-end hub 1102 and a front-end rim 1101 arranged in concentric circles. A front-end blade 1100 is provided between the front-end hub 1102 and the front-end rim 1101. A front-end tapered flow channel 1103 is provided at the rear position of the front-end rim 1101. The inner diameter of the front-end tapered flow channel 1103 gradually becomes smaller from front to back, and a front-end boosting spray ring 1104 is formed between the small-diameter section of the front-end tapered flow channel 1103 and the front-end hub 1102.

[0063] This structure sucks in the cold gas near the front-end cover 10. The front-end blade 1100, the front-end rim 1101, and the front-end hub 1102 form a mechanical rotating component, which pressurizes and accelerates the sucked-in cold gas. After passing through the front-end tapered flow channel 1103 (converting the pressure energy of the gas into kinetic energy), a high-speed gas flow is formed and ejected from the front-end boosting spray ring 1104.

[0064] The front-end blades 1100 are evenly distributed in the axial direction. The number of blades is (in this embodiment, is taken), which is equal to the circumferential magnetic pole logarithm (the total number of poles , in this embodiment, is taken), and the installation angle Calculated according to the following formula: . Through the number of blades and the installation angle of the blade to achieve phase decoupling from the pole pair magnetic field, reducing the electromagnetic-aerodynamic coupling noise.

[0065] The front-end boosting spray ring 1104 is distributed in the same size along the circumferential direction, and the throat width is taken (unit: mm), is the outer diameter of the rotor self-driven cooling iron core (unit: mm), is the radial thickness of the magnetic pole (unit: mm). Calculate according to the following formula: . Assume that the gas reaches the inlet cross-sectional area of after being boosted and accelerated by the blade (unit: m 2 ), and the corresponding average flow velocity is (unit: m / s). The cross-sectional area of the nozzle outlet is (unit: m 2 ), and the corresponding average flow velocity is (unit: m / s). The density of the injected fluid at the temperature of °C is (kg / m 3 ). Select the desired boost value as (Pa) according to the limit power of different motors, The calculation formula of is: . The throat width completely covers the magnetic pole thickness, forming a full circumferential strong cooling. Design the nozzle flow velocity according to the motor limit power to ensure the cooling capacity under the limit condition.

[0066] As Figure 2 shown, the rotor core cooling secondary drainage part includes the front-end gas main input channel 1110 and the front-end airfoil curved wall flow channel 1111.

[0067] There is a radial distance between the front-end hub 1102 and the rotating shaft 6, forming the front-end gas main input channel 1110.

[0068] The front-end tapered flow channel 1103 is connected to the front-end airfoil curved wall flow channel 1111 at the back. The high-speed gas ejected from the front-end boosting spray ring 1104 forms a low-pressure area on the front-end airfoil curved wall flow channel 1111. A large amount of gas is inhaled axially along the front-end gas main input channel 1110 to the vicinity of the low-pressure area and continues to flow axially according to the Coandă effect.

[0069] The front-end gas main input channel 1110 is connected to the front end of the front-end airfoil curved wall flow channel 1111, and the back end of the front-end airfoil curved wall flow channel 1111 is connected to the front end of the rotor core cooling tertiary ventilation self-driven flow channel 31.

[0070] The leading-edge radius of curvature of the front airfoil curved-wall flow channel 1111 (unit: mm) is designed based on the critical radius formula of the Coandă effect by taking the rated operating point: . Among them, assuming that the rated rotational speed is (unit: rpm), The dynamic viscosity, kinematic viscosity and density of the gas at (unit: Pa·s) and (unit: kg / m 3 ), the outer radius of the rotor core is , and the Reynolds number calculated according to this condition is . In addition, the axial length of the flow channel , the radius of curvature , where is the acceleration due to gravity. Based on this airfoil design method, the turbulence intensity will be reduced and the Nusselt number of the airfoil wall surface will be increased.

[0071] As Figure 2 shown, the four-stage pressure-relieving flow channel 113 for pole cooling is located radially outside the front airfoil curved-wall flow channel 1111, and the rear end of the four-stage pressure-relieving flow channel 113 for pole cooling is connected to the front end of the three-stage back-gap self-driven flow channel 32 for pole cooling. The four-stage pressure-relieving flow channel 113 for pole cooling is gradually widened as a whole along the gas flow direction, so that the kinetic energy of the gas is gradually converted into pressure energy, and a high-pressure area is formed in this area to prevent the reverse inflow of external gas.

[0072] A spacing is left axially between the front end of the four-stage pressure-relieving flow channel 113 for pole cooling and the front rim 1101, and it cooperates with the outer wall surface of the front tapered flow channel 1103 to form a wall gas outlet, and the wall gas outlet corresponds to the stator winding end at the front end.

[0073] In this way, in cooperation with the arc-shaped radial curved surface of the front tapered flow channel 1103 at the wall gas outlet, the gas flows radially, enhancing the heat exchange between the stator winding end 8 and the gas.

[0074] The components of the front drive structure 1 are respectively connected by circumferentially distributed front support columns 1130 between the radial directions and between the front drive structure 1 and the rotating shaft 6 to ensure the overall structural strength under high-speed conditions. The number of the front support columns 1130 is (in this embodiment, take ), and a rhombic cross-section (the diagonal lengths are respectively and , and the cross-sectional area is ) is adopted to ensure the support strength and reduce the flow resistance. Assuming that the centrifugal force received by the outer end face at the outlet under the rated rotational speed is (unit: N), by adjusting the in the stress diffusion formula and to reduce the stress concentration factor.

[0075] As Figure 3 shown, the first-stage boosting part of the pole cooling includes a rear end rim 2101 and a rear end hub 2102 arranged in concentric circles. A rear end blade 2100 is provided between the rear end rim 2101 and the rear end hub 2102. The rear end rim 2101 is connected forward with a rear end tapered flow channel. The inner diameter of the rear end tapered flow channel gradually decreases from the rear to the front, and a rear end boosting spray ring 2103 is formed between the small-diameter section of the rear end tapered flow channel 2103 and the rear end hub 2102.

[0076] The rear end blade 2100, the rear end rim 2101 and the rear end hub 2102 constitute a mechanical rotating component, which pressurizes and accelerates the inhaled cold gas. After passing through the rear end tapered flow channel (converting the pressure energy of the gas into kinetic energy), a high-speed gas flow is formed and ejected from the rear end boosting spray ring 2103. The parameters of the rear end blade 2100 are the same as those of the front end blade 1100. The number of blades is , and the installation angle is , and the leading edge curvature radius (unit: mm). The gyroscopic effect is offset by the mirror-symmetric blade layout, effectively reducing the amplitude of rotor vibration.

[0077] As Figure 3 shown, the second-stage gas diversion part of the pole cooling includes a rear end airfoil curved wall flow channel 2111. The rear end airfoil curved wall flow channel 2111 is provided at the forward position of the rear end tapered flow channel. The high-speed gas ejected from the rear end boosting spray ring 2103 is sprayed at the rear end airfoil curved wall flow channel 2111; the front end of the rear end airfoil curved wall flow channel 2111 is connected to the third-stage back-gap self-driven flow channel 32 of the pole cooling.

[0078] There is an axial distance between the rear end of the rear end airfoil curved wall flow channel 2111 and the rear end rim 2101, and it cooperates with the outer wall surface of the rear end tapered flow channel to form a wall surface gas inlet 2110. The wall surface gas inlet 2110 corresponds to the end part of the stator winding 8 at the rear end.

[0079] The wall surface gas inlet 2110 serves as the main input port for the rear end gas. The high-speed gas ejected from the rear end boosting spray ring 2103 forms a low-pressure area in the rear end airfoil curved wall flow channel 2111. A large amount of gas is inhaled near the low-pressure area through the wall surface gas inlet 2110 and continues to flow axially according to the Coandă effect.

[0080] As Figure 3As shown, the four-stage pressure-relief flow channel 212 for rotor core cooling is located radially inside the rear hub 2102 and has a radial gap with the rotating shaft 6. The four-stage pressure-relief flow channel 212 for rotor core cooling is tapered as a whole along the gas flow direction, and it can form a pressure decreasing gradient along the flow direction, enabling the gas to flow spontaneously from the high-pressure side to the low-pressure side.

[0081] The front end of the four-stage pressure-relief flow channel 212 for rotor core cooling is connected to the rear end of the three-stage ventilation self-driven flow channel 31 for rotor core cooling, and the rear end of the four-stage pressure-relief flow channel 212 for rotor core cooling extends to be basically flush with the rear end of the rear hub 2102.

[0082] Regarding the taper of the four-stage pressure-relief flow channel 212 for rotor core cooling Parameter design: Assume the axial length of the tapered flow channel is , the radial heights at the inlet and outlet are and respectively, the inlet flow velocity is (m / s), and the cone angle can be calculated. The outlet flow velocity . The pressure gradient is maintained at a certain level through to reduce the recirculation rate.

[0083] Each component of the rear-end drive structure 2 is connected by circumferentially distributed rear-end support columns 2120 between the radial directions and between the rear-end drive structure 2 and the rotating shaft 6 to ensure the overall structural strength under high-speed conditions. Assume the number of rear-end support columns 2120 is (in this embodiment , a rhombus cross-section is adopted, and the diagonal lengths are and respectively, and the cross-sectional area is ) to ensure the support strength and reduce the flow resistance; assume the centrifugal force on the outer end face at the outlet under the rated speed is (unit: N). By adjusting in the stress diffusion formula and to reduce the stress concentration coefficient. As Figures 4 to 6As shown, the rotor self-driven heat dissipation structure 3 is processed by a segmented assembly method. Each iron core segment 30 is laminated with silicon steel sheet punched sheets at an offset angle. This structure not only reduces the eddy current loss of the rotor iron core, but the segmented assembly method can make the internal flow channel wall smoother to reduce the flow resistance. The magnetic poles 4 are segmented axially to reduce the eddy current loss and have the same axial segmented length as the iron core segment 30, facilitating the fixed processing technology for each magnetic pole 4 and each iron core segment 30. When the rotor self-driven heat dissipation iron core fixed on the rotating shaft 6 rotates, the front-end drive structure 1 and the rear-end drive structure 2 will send gases in opposite directions into the rotor iron core cooling three-stage ventilation self-driven flow channel 31 and the magnetic pole cooling three-stage back-gap self-driven flow channel 32 in the rotor self-driven heat dissipation iron core. At the same time, due to the self-driving ability of the slots they have, the gases will be transported along the corresponding directions.

[0084] Magnetic pole-hole collaborative design method for the rotor iron core cooling three-stage ventilation self-driven flow channel 31:

[0085] Assume the number of arc-shaped special-shaped holes is (in this embodiment ), and they are evenly distributed circumferentially (assuming each pole of the motor technology corresponds to a hole). To ensure both the structural strength and the ventilation and heat dissipation ability at the same time, the circumferential span of the arc-shaped holes is half of the circumferential span of the magnetic poles, and the width is the same as the throat width of the pressure boosting nozzle; the axial misalignment angle , is the axial length of the flow channel of each iron core segment (unit: mm), is the outer diameter of the rotor self-driven heat dissipation iron core (unit: mm). The proportion of the hole area meets the rotor structural strength at high speeds and reaches the maximum flow rate requirement. The misalignment angle generates an axial pressure gradient to drive the gas to penetrate the iron core and achieve the goal of gas self-driving.

[0086] (2) Magnetic pole cooling three-stage back-gap self-driven flow channel 32 - Magnetic pole thermal stress decoupling design method:

[0087] The number of magnetic pole cooling three-stage back-gap self-driven flow channels 32 is (to ensure , 2 is taken in this embodiment). The magnetic pole cooling three-stage back-gap self-driven flow channel 32 is a special-shaped hole, approximately half of an ellipse, with the length of the long axis of the cross-section (unit: mm), the length of the short axis (unit: mm), the absolute length of the special-shaped hole is (unit: mm), the angular velocity (unit: rad / s), the twist angle , and the expected pressure boosting ability of this stage is . The mass flow rate is enhanced according to the formula , and at the same time, the temperature rise gradient of the magnetic pole back-gap is reduced.

[0088] The working principle of the present invention is as follows:

[0089] Since the motor has a periodic symmetric structure, the upper cross-section of the motor is selected to illustrate the internal flow and heat dissipation of the motor, as Figure 7 shown. It is assumed that the environmental temperature keeps the temperatures of the motor housing 9, the front end cover 10, and the rear end cover 11 constant at T 0 , and the gas temperatures at the near-wall surfaces of the three are also T 0 .

[0090] For the cooling process inside the rotor self-driven heat dissipation structure 3:

[0091] The front-end pressurized gas 1105 is pressurized, accelerated by the rotor core cooling first-stage pressurization part 110, and ejected from the front-end pressurized spray ring 1104, driving the confluence of the large amount of front-end gas 1106 to form the front-end injected gas 1112 of the rotor core cooling three-stage ventilation self-driven flow channel 31. At this time, the gas temperature is T 1 . As the rotor rotates, the injected gas 1112 takes away the heat inside the rotor self-driven heat dissipation structure 3 and is thrown out to become the hot gas 2121 with a temperature of T 4 , and then flows axially to the rear end cover 11 for cooling.

[0092] For the back-gap cooling process between the rotor self-driven heat dissipation structure 3 and the magnetic pole 4:

[0093] The rear-end pressurized gas 2104 is pressurized, accelerated by the magnetic pole cooling first-stage pressurization part 210, and ejected from the rear-end pressurized spray ring 2103, forming a low-pressure area at the rear-end airfoil curved wall flow channel 2111. Therefore, the cold gas 82 at the rear-end near-wall surface between the motor housing 9 and the end part of the stator winding 8 is inhaled. The two types of gases converge to form the rear-end injected gas 2113 of the rotor magnetic pole cooling three-stage back-gap self-driven flow channel 32. At this time, the gas temperature is T 2 . As the rotor rotates, the rear-end injected gas 2113 takes away the heat between the magnetic pole 4 and the rotor self-driven heat dissipation structure 3 and becomes the heated gas 1131 with a temperature of T 4 . Then, it flows axially, is radially thrown out, accelerates the flow rate of the gas on the surface of the end part of the stator winding 8, and cools it, forming a hotter gas 81 with a temperature of T 6 that flows to the wall surface of the motor housing 9 for cooling.

[0094] Embodiment 2:

[0095] This embodiment discloses a motor that uses the motor rotor cooling structure of Embodiment 1.

[0096] The motor includes a front-end drive structure 1, a rear-end drive structure 2, a rotor self-driven heat dissipation structure 3, magnetic poles 4, a sheath 5, a rotating shaft 6, a stator core 7, stator winding ends 8, a motor housing 9, a front end cover 10, and a rear end cover 11.

[0097] The front-end drive structure 1, the rear-end drive structure 2, and the rotor self-driven heat dissipation structure 3 are located within the motor base. The front-end drive structure 1 is close to the front end cover 10, and the rear-end drive structure 2 is close to the rear end cover 11. The outer sides of the motor housing 9, the front end cover 10, and the rear end cover 11 all have heat dissipation ribs, and the internal gas can obtain sufficient heat exchange when contacting their inner surfaces.

[0098] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the present invention without departing from the spirit and scope of the present invention, and any modification or partial replacement should be covered within the scope of the claims of the present invention.

[0099] If terms such as "first" and "second" are used in this article to limit components, those skilled in the art should know that the use of "first" and "second" is only for the convenience of describing the present invention and simplifying the description. Without additional statements, these terms have no special meanings.

[0100] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

[0101] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

Claims

1. A motor rotor cooling structure, comprising a rotating shaft, characterized in that: The front drive structure, the middle rotor self-driven heat dissipation structure and the rear drive structure are fixed in sequence on the shaft along the axial direction, and the three rotate together with the shaft; The front-end drive structure includes a first-stage booster section for rotor core cooling, a second-stage drainage section for rotor core cooling, and a fourth-stage pressure relief channel for magnetic pole cooling; The rotor self-driven heat dissipation structure includes a rotor core, a magnetic pole fixed outside the rotor core, and a sheath. The rotor core is provided with a three-stage ventilation self-driven flow channel for rotor core cooling, and a three-stage back-gap self-driven flow channel for magnetic pole cooling is provided near the bottom of the magnetic pole. The rear-end drive structure includes a first-stage booster part for magnetic pole cooling, a second-stage drainage part for magnetic pole cooling, and a fourth-stage pressure relief flow channel for the rotor core; The rotor core cooling first-stage boosting part, the rotor core cooling second-stage drainage part, the rotor core cooling third-stage ventilation self-driving flow channel and the rotor core fourth-stage pressure relief flow channel are connected in sequence, and the gas flow direction is from front to back; The first-stage boosting part of the magnetic pole cooling, the second-stage drainage part of the magnetic pole cooling, the third-stage back-gap self-driven flow channel of the magnetic pole cooling, and the fourth-stage pressure relief flow channel of the magnetic pole cooling are connected in sequence, and the gas flow direction is from back to front; The first-stage supercharging part of the rotor core cooling system includes a front hub and a front rim arranged in a concentric circle. Front blades are provided between the front hub and the front rim. A front tapered flow channel is provided rearward of the front rim. The inner diameter of the front tapered flow channel gradually decreases from front to back, and a front supercharging spray ring is formed between the small-diameter section of the front tapered flow channel and the front hub. The rotor core cooling secondary drainage part includes a front-end gas main body input channel and a front-end airfoil curved wall flow channel; There is a radial distance between the front hub and the rotating shaft, forming a front gas main body input channel; The front end tapered flow channel is connected to the front end airfoil curved wall flow channel backward, and the high-speed gas ejected by the front end booster spray ring is sprayed on the front end airfoil curved wall flow channel; The front gas main body input channel is connected to the front end of the front airfoil curved wall flow channel, and the rear end of the front airfoil curved wall flow channel is connected to the front end of the rotor core cooling three-stage ventilation self-driven flow channel; The four-stage pressure relief flow channel for magnetic pole cooling is located radially outside the front airfoil curved wall flow channel, and the four-stage pressure relief flow channel for magnetic pole cooling is gradually widened along the gas flow direction; There is an axial distance between the front end of the four-stage pressure relief flow channel for magnetic pole cooling and the front wheel rim, and the wall gas outlet is formed in conjunction with the outer wall of the front tapered flow channel. The wall gas outlet corresponds to the stator winding end at the front end. The rear end of the fourth-stage pressure relief flow channel for magnetic pole cooling is connected to the front end of the third-stage backlash self-driven flow channel for magnetic pole cooling; The first-stage supercharging part of the magnetic pole cooling includes a rear end hub and a rear end rim arranged in concentric circles, with rear end blades provided between the rear end hub and the rear end rim, and a rear end tapered flow channel connected forwardly to the rear end rim, the inner diameter of the rear end tapered flow channel gradually decreases from rear to front, and a rear end supercharging spray ring is formed between the small diameter section of the rear end tapered flow channel and the rear end hub; The secondary drainage part of the magnetic pole cooling includes a rear airfoil curved wall flow channel; A rear airfoil curved wall flow channel is provided forward of the rear end tapered flow channel, and high-speed gas ejected from the rear end booster spray ring is sprayed onto the rear end airfoil curved wall flow channel; the front end of the rear end airfoil curved wall flow channel is connected to the third-stage back-gap self-driven flow channel for magnetic pole cooling; A distance is left in the axial direction between the rear end of the rear airfoil curved wall flow channel and the rear end wheel rim, and cooperates with the outer wall surface of the rear end tapered flow channel to form a wall gas inlet, which corresponds to the rear end stator winding end; The four-stage pressure relief flow channel for cooling the rotor core is located radially inward of the rear hub and is radially spaced from the rotating shaft. The four-stage pressure relief flow channel for cooling the rotor core is tapered along the direction of gas flow. The front end of the rotor core cooling four-stage pressure relief flow channel is connected to the rear end of the rotor core cooling three-stage ventilation self-driven flow channel, and the rear end of the rotor core cooling four-stage pressure relief flow channel extends to be basically flush with the rear end of the rear end hub.

2. The motor rotor cooling structure according to claim 1, characterized in that: The components of the front-end drive structure / the rear-end drive structure are connected radially and between the front-end drive structure / the rear-end drive structure and the rotating shaft respectively through circumferentially distributed support columns, and the support columns have diamond-shaped cross-sections.

3. The motor rotor cooling structure according to claim 1, characterized in that: The rotor core is divided into multiple core segments. Each core segment is stacked with silicon steel sheets at staggered angles, so that the three-stage ventilation self-driven flow channel for rotor core cooling / three-stage backlash self-driven flow channel for magnetic pole cooling are offset at a certain angle to the axial direction, thereby generating axial thrust on the gas.

4. A motor, characterized in that: The motor rotor cooling structure includes the motor rotor cooling structure described in any one of claims 1 to 3, the motor rotor cooling structure is located in the machine base, the machine base includes a casing, a front end cover and a rear end cover, the front end drive structure is close to the front end cover, the rear end drive structure is close to the rear end cover, and the outer sides of the casing, the front end cover and the rear end cover all have heat dissipation structures.

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