Motor rotor cooling structure and motor

Abstract

The invention discloses a motor rotor cooling structure and a motor, and the motor rotor cooling structure comprises a front-end driving structure, a rotor self-dispersing heat dissipation structure and a rear-end driving structure which rotate along with a rotating shaft. The front-end driving structure comprises a rotor core cooling first-stage pressurizing part, a rotor core cooling second-stage drainage part and a magnetic pole cooling fourth-stage pressure releasing runner; the rotor self-driving heat dissipation structure comprises a rotor iron core and a magnetic pole and a sheath which are fixed outside the rotor iron core, a rotor iron core cooling three-stage ventilation self-driving flow channel is arranged at the rotor iron core, and a magnetic pole cooling three-stage back clearance self-driving flow channel is arranged at the position close to the bottom of the magnetic pole; and the rear-end driving structure comprises a magnetic pole cooling first-stage pressurizing part, a magnetic pole cooling second-stage drainage part and a rotor iron core fourth-stage pressure release runner. Through the design of the opposite pressurizing blades of the inner layer and the outer layer and the twisted flow channels, one-way flow limitation is broken through, Keanda effect self-compensation of airflow is achieved, and opposite double-layer powerful cooling of the magnetic poles and the rotor iron core is achieved.

Description

Technical Field

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

[0002] Due to its compact structure and high power density characteristics, the air-cooled radial-flux high-speed motor has shown significant advantages in the fields of new energy vehicle drive, aerospace propulsion, etc. To meet the demand for power density improvement in ultra-high speed scenarios, its development trend towards smaller volume and higher efficiency is irreversible. However, with the synchronous increase in 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 the rotor region has long relied on gas self-cooling due to the problems of rotary sealing and centrifugal force limitation, and 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 mainly fall into two categories: External enhanced air cooling: By optimizing the end fan blades (such as diagonal flow type, centrifugal type), the air gap flow rate is increased, but the mechanical losses generated by the coaxially mounted fan at high speeds account for a large proportion, and the uneven air flow distribution easily leads to a relatively high axial temperature gradient.

[0004] Internal indirect liquid cooling: Adopting hollow shaft internal circulation oil cooling or microchannel 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 significantly, and the mechanical failure rate is relatively high.

[0005] In addition to the above problems, the existing rotor cooling technologies also have the following main defects: First: Uneven air flow distribution and secondary flow loss.

[0006] 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 the Coandă effect deviation caused by centrifugal force at high speeds forms a local overheating area (the temperature at the edge of the permanent magnet is higher than the center temperature).

[0007] Existing jet orifice 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.

[0008] Second: The material properties cannot solve the problem of thermal stress concentration.

[0009] The internal flow channels of the surface-mounted rotor core are mostly straight lines or simple arcs, unable to adapt to the dynamic deformation caused by centrifugal force, resulting in micro-cracks at the interface between the flow channel and the permanent magnet.

[0010] 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, nor can it effectively dissipate heat in the back gap of the permanent magnet.

[0011] Third: The contradiction between cooling efficiency and system complexity.

[0012] 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.

[0013] Phase change cooling (such as microchannel heat pipes) can reduce the hot spot temperature, but it will introduce a problem of controlling the filling rate of the working fluid (a deviation in the optimal filling rate will cause a large fluctuation in the heat transfer performance). Summary of the Invention

[0014] 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 art to a certain extent.

[0015] To achieve the above-mentioned invention purpose, the present invention adopts the following technical solutions: A motor rotor cooling structure includes a rotating shaft, on which a front-end drive structure, a middle rotor self-driven heat dissipation structure, and a rear-end drive structure are sequentially fixed along the axial direction. The three rotate together with the rotating shaft; The front-end drive structure includes a first-stage supercharging 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; The rotor self-driven heat dissipation structure includes a rotor core, and magnetic 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 magnetic pole cooling is provided near the bottom of the magnetic pole; The rear-end drive structure includes a first-stage supercharging 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; The first-stage supercharging 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; The first-stage supercharging 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.

[0016] Furthermore, the first-stage supercharging part for rotor core cooling includes a front-end hub and a front-end rim arranged in concentric circles. Front-end blades are provided between the front-end hub and the front-end rim. A front-end tapered flow channel is provided at the rear position of the front-end rim. The inner diameter of the front-end tapered flow channel gradually becomes smaller from front to back, and a front-end supercharging spray ring is formed between the small-diameter section of the front-end tapered flow channel and the front-end hub.

[0017] Further, the second-stage drainage part of the rotor core cooling includes a front-end gas main input channel and a front-end airfoil curved wall flow channel; There is a radial gap between the front-end hub and the rotating shaft, forming the front-end gas main input channel; The front-end tapered flow channel is connected to the front-end airfoil curved wall flow channel at the back, and the high-speed gas ejected from the front-end booster spray ring is sprayed at the front-end airfoil curved wall flow channel; The front-end gas main input channel is communicated with the front end of the front-end airfoil curved wall flow channel, and the back end of the front-end airfoil curved wall flow channel is communicated with the front end of the third-stage ventilation self-driven flow channel of the rotor core cooling.

[0018] Further, the fourth-stage pressure relief flow channel of the pole cooling is located radially outside the front-end airfoil curved wall flow channel, and the fourth-stage pressure relief flow channel of the pole cooling is gradually widened as a whole along the gas flow direction; There is an axial gap between the front end of the fourth-stage pressure relief flow channel of the pole cooling and the front-end rim, and it cooperates with the outer wall surface of the front-end tapered flow channel to form a wall surface gas outlet, and the wall surface gas outlet corresponds to the end part of the stator winding at the front end; The back end of the fourth-stage pressure relief flow channel of the pole cooling is communicated with the front end of the third-stage back-gap self-driven flow channel of the pole cooling.

[0019] Further, the first-stage boosting part of the pole cooling includes a rear-end hub and a rear-end rim arranged in concentric circles. There are rear-end blades between the rear-end hub and the rear-end rim. The rear-end rim is connected to the front with a rear-end tapered flow channel. The inner diameter of the rear-end tapered flow channel gradually becomes smaller from the back to the front, and a rear-end booster spray ring is formed between the small-diameter section of the rear-end tapered flow channel and the rear-end hub.

[0020] Further, the second-stage drainage part of the pole cooling includes a rear-end airfoil curved wall flow channel; The rear-end airfoil curved wall flow channel is arranged at the front position of the rear-end tapered flow channel, and the high-speed gas ejected from the rear-end booster spray ring is sprayed at the rear-end airfoil curved wall flow channel; the front end of the rear-end airfoil curved wall flow channel is communicated with the third-stage back-gap self-driven flow channel of the pole cooling; There is an axial gap between the back end of the rear-end airfoil curved wall flow channel and the rear-end rim, and it cooperates with the outer wall surface of the rear-end tapered flow channel to form a wall surface gas inlet, and the wall surface gas inlet corresponds to the end part of the stator winding at the rear end.

[0021] Further, the fourth-stage pressure relief flow channel of the rotor core cooling is located radially inside the rear-end hub and has a radial gap with the rotating shaft. The fourth-stage pressure relief flow channel of the rotor core cooling is gradually tapered as a whole along the gas flow direction; The front end of the fourth-stage pressure relief flow channel of the rotor core cooling is communicated with the back end of the third-stage ventilation self-driven flow channel of the rotor core cooling, and the back end of the fourth-stage pressure relief flow channel of the rotor core cooling extends to be basically flush with the back end of the rear-end hub.

[0022] Furthermore, the components of the front-end drive structure / rear-end drive structure are respectively 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. The support columns have a diamond cross-section.

[0023] Furthermore, the rotor core is divided into multiple core segments. Each core segment is laminated with silicon steel sheet punched parts at a staggered angle, 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 staggered angle with the axial direction, thereby generating an axial thrust on the gas.

[0024] 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, and the rear-end drive structure is close to the rear end cover. Heat dissipation structures are provided on the outer sides of the machine shell, the front end cover, and the rear end cover.

[0025] The beneficial effects of the present invention are as follows: 1. Through the design of the opposing pressurizing blades and the twisted flow channels in the inner layer and the outer layer, the present invention breaks through the unidirectional 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.

[0026] 2. By using the special-shaped topology of the back-gap groove at the bottom of the magnetic pole (the three-stage back-gap self-driven flow channel for pole cooling), 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.

[0027] 3. The present invention constructs a fully autonomous heat dissipation system: The inlet and outlet flow channels are not only coupled with the internal flow channels of the rotor through the heat conduction structure of the end cover to realize gas cooling, but also can accelerate the flow of the stator winding end to improve the heat dissipation capacity of this part. At the same time, the external oil pump / fan is cancelled, improving the reliability of the system. Description of the Drawings

[0028] Figure 1 is the overall schematic diagram of the present invention; Figure 2 is the schematic diagram of the front-end drive structure in the present invention; Figure 3 is the schematic diagram of the rear-end drive structure in the present invention; Figure 4 is the schematic diagram of the rotor self-driven heat dissipation structure in the present invention; Figure 5 is Figure 4 the side view of; Figure 6 is the schematic diagram of the layer-by-layer disassembly of the rotor self-driven heat dissipation structure in the present invention; Figure 7 is the schematic diagram of the internal flow heat dissipation in the motor of the present invention.

[0029] The accompanying drawings are only for illustrative purposes and should not be construed as limiting the present application; for better illustration of this embodiment, some components in the drawings may be omitted, enlarged or reduced, which does 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 drawings may be omitted. Detailed implementation manners

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0031] Embodiment 1: As Figures 1 to 7 shown, this embodiment discloses a motor rotor cooling structure, including a rotating shaft 6. Along the axial direction of the rotating shaft 6, a front-end driving structure 1, a middle rotor self-driving heat dissipation structure 3, and a rear-end driving structure 2 are sequentially provided. The front-end driving structure 1, the rear-end driving structure 2, and the rotor self-driving 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.

[0032] The front-end driving structure includes a first-stage supercharging 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 driving 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 cycle at the front end of the rotor self-driving heat dissipation structure 3.

[0033] The rotor self-driving heat dissipation structure includes a rotor core and poles 4. The poles 4 are fixed on the rotor core, and the outside is reinforced with a sheath 5 to form a surface-mounted rotor form. A third-stage ventilation self-driving flow channel 31 for rotor core cooling is provided at the middle position of the rotor core, and a third-stage back-gap self-driving flow channel 32 for pole cooling is provided near the poles on the outside of the rotor core.

[0034] The rear-end driving structure 2 includes a first-stage supercharging part 210 for pole cooling, a second-stage drainage part 211 for pole cooling, and a fourth-stage pressure relief flow channel 213 for rotor core. The rear-end driving structure 2 is close to the rear-end cover 11 of the motor and is fixed on the rotating shaft 6, and is used for the gas flow cycle at the rear end of the rotor self-driving heat dissipation structure 3.

[0035] The first-stage supercharging part 110 for rotor core cooling, the second-stage drainage part 111 for rotor core cooling, the third-stage ventilation self-driving flow channel 31 for rotor core cooling, and the fourth-stage pressure relief flow channel 213 for rotor core are connected, and the gas flow direction is from front to back. This part of the air path is mainly used for cooling the rotor core.

[0036] The first-stage supercharging section 210 for pole cooling, the second-stage diversion section 211 for pole cooling, the third-stage back-gap self-driven flow channel 32 for pole cooling, and the fourth-stage pressure relief flow channel 113 for pole cooling are connected, and the gas flow direction is from the back to the front. This part of the air path is mainly used to cool the poles.

[0037] The specific settings of the above structures will be described in detail below.

[0038] As Figure 2 shown, the first-stage supercharging section for rotor core cooling includes a front hub 1102 and a front rim 1101 arranged in concentric circles. A front blade 1100 is provided between the front hub 1102 and the front rim 1101. A front tapered flow channel 1103 is provided at the rear position of the front rim 1101. The inner diameter of the front tapered flow channel 1103 gradually decreases from the front to the rear, and a front supercharging spray ring 1104 is formed between the small-diameter section of the front tapered flow channel 1103 and the front hub 1102.

[0039] This structure sucks in the cold gas near the front end cover 10. The front blade 1100, the front rim 1101, and the front hub 1102 form a mechanical rotating component, pressurize and accelerate the inhaled cold gas, and form a high-speed gas flow through the front tapered flow channel 1103 (converting the pressure energy of the gas into kinetic energy) and eject it from the front supercharging spray ring 1104.

[0040] The front 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 pole logarithm (total number of poles , in this embodiment, is taken). The installation angle is calculated according to the following formula: . Through the blades with the number of blades and the installation angle , the phase decoupling of the -pole magnetic field is achieved, reducing the electro-magnetic-aero coupling noise.

[0041] The front supercharging spray rings 1104 are distributed with the same size in the circumferential direction. The throat width (unit: mm) is taken, is the outer diameter of the rotor self-driven cooling iron core (unit: mm), is the radial thickness of the pole (unit: mm). It is calculated according to the following formula: . Assume that the gas reaches the inlet cross-sectional area (unit: m 2 ) after being pressurized and accelerated by the blades, and the corresponding average flow velocity is (unit: m / s). The outlet cross-sectional area of the nozzle is (unit: m 2), and the corresponding average flow velocity is (unit: m / s), and the temperature At ℃, the density of the jet fluid is (kg / m 3 ). Select the desired boost value according to the limit power of different motors as (Pa), The calculation formula of is: . The throat width completely covers the pole thickness to form a full circumferential strong cooling. Design the nozzle flow velocity according to the motor limit power to ensure the cooling capacity under extreme conditions.

[0042] As Figure 2 shown, the rotor core cooling secondary drainage part includes a front-end gas main input channel 1110 and a front-end airfoil curved wall flow channel 1111.

[0043] There is a radial distance between the front hub 1102 and the rotating shaft 6 to form a front-end gas main input channel 1110.

[0044] 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 boost 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.

[0045] 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.

[0046] The leading edge curvature radius of the front-end airfoil curved wall flow channel 1111 (unit: mm) is designed based on the Coandă effect critical radius formula at the rated operating point: . Among them, assuming that the rated speed is (unit: rpm), At ℃, the dynamic viscosity, kinematic viscosity and density of the gas are respectively (unit: Pa·s) and (unit: kg / m 3 ), and the outer radius of the rotor core is . The Reynolds number calculated according to this condition is . In addition, the axial length of the flow channel , the curvature radius , 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.

[0047] AsFigure 2 As shown in the figure, the four - stage pressure - relief flow channel 113 for pole cooling is located radially outside the front - end airfoil curved - wall flow channel 1111. The rear end of the four - stage pressure - relief flow channel 113 for pole cooling is communicated with the front end of the three - stage back - clearance self - driving flow channel 32 for pole cooling. The four - stage pressure - relief 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, forming a high - pressure area in this region to prevent the reverse inflow of external gas.

[0048] There is an axial distance between the front end of the four - stage pressure - relief flow channel 113 for pole cooling and the front - end rim 1101, and it cooperates with the outer wall surface of the front - end tapered flow channel 1103 to form a wall - surface gas outlet, and the wall - surface gas outlet corresponds to the end of the stator winding at the front end.

[0049] In this way, in cooperation with the arc - shaped radial curved surface of the front - end tapered flow channel 1103 at the wall - surface gas outlet, the gas flows radially, enhancing the heat exchange between the end of the stator winding 8 and the gas.

[0050] Each component of the front - end drive structure 1 is connected by circumferentially distributed front - end support columns 1130 respectively between the radial directions and between the front - end drive structure 1 and the rotating shaft 6 to ensure the overall structural strength under high - speed conditions. The number of the front - end support columns 1130 is (in this embodiment, take ), and a diamond - shaped 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 on the outer end face of the outlet under the rated speed is (unit: N), by adjusting in the stress diffusion formula and to reduce the stress concentration coefficient.

[0051] As Figure 3 shown, the first - stage boosting part for 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, and the inner diameter of the rear - end tapered flow channel gradually becomes smaller 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.

[0052] The rear - end blade 2100, the rear - end rim 2101 and the rear - end hub 2102 form a mechanical rotating part, 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, and the number of blades is , the installation angle is , the leading edge radius of curvature (unit: mm). The gyroscopic effect is offset by the mirror-symmetric blade layout, effectively reducing the amplitude of rotor vibration.

[0053] As Figure 3 shown, the second-stage drainage part of the pole cooling includes the rear airfoil curved wall flow channel 2111. The rear tapered flow channel is provided with the rear airfoil curved wall flow channel 2111 at the forward position. The high-speed gas ejected from the rear pressure-increasing spray ring 2103 is sprayed at the rear airfoil curved wall flow channel 2111; the front end of the rear airfoil curved wall flow channel 2111 is communicated with the third-stage back-gap self-driven flow channel 32 of the pole cooling.

[0054] There is an axial gap between the rear end of the rear airfoil curved wall flow channel 2111 and the rear rim 2101, and it cooperates with the outer wall surface of the rear tapered flow channel to form a wall surface gas inlet 2110. The wall surface gas inlet 2110 corresponds to the end of the stator winding 8 at the rear end.

[0055] The wall surface gas inlet 2110 serves as the main input port for the rear gas. The high-speed gas ejected from the rear pressure-increasing spray ring 2103 forms a low-pressure area in the rear airfoil curved wall flow channel 2111. A large amount of gas is inhaled to the vicinity of the low-pressure area through the wall surface gas inlet 2110 and continues to flow axially according to the Coandă effect.

[0056] As Figure 3 shown, the fourth-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 fourth-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.

[0057] The front end of the fourth-stage pressure-relief flow channel 212 for rotor core cooling is communicated with the rear end of the third-stage ventilation self-driven flow channel 31 for rotor core cooling, and the rear end of the fourth-stage pressure-relief flow channel 212 for rotor core cooling extends to be basically flush with the rear end of the rear hub 2102.

[0058] Regarding the parameter design of the taper of the fourth-stage pressure-relief flow channel 212 for rotor core cooling: Assuming the axial length of the tapered flow channel is , the radial heights of the inlet and outlet are respectively and , the inlet flow velocity is (m / s), the cone angle can be calculated, and the outlet flow velocity . The pressure gradient is maintained at a certain level through to reduce the recirculation rate.

[0059] Each component of the rear-end drive structure 2 is connected by circumferentially distributed rear-end support columns 2120 respectively between the radial directions and between the rear-end drive structure 2 and the rotating shaft 6, ensuring the overall structural strength under high-speed conditions. Assume the number of rear-end support columns 2120 is (In this embodiment , a rhombic cross-section is adopted, and the diagonal lengths are respectively and , and the cross-sectional area is ) to ensure the support strength and reduce the flow resistance; assume the centrifugal force received by the outer end face of the outlet under the rated speed is (unit: N). By adjusting the stress diffusion formula in and to reduce the stress concentration coefficient. As Figures 4 to 6 shows, 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 angular offset. This structure not only reduces the eddy current loss of the rotor iron core, but the segmented assembly method can make the inner wall of the flow channel smoother to reduce the flow resistance. The magnetic poles 4 are segmented axially to reduce the eddy current loss, and the axial segmented length is the same as that of the iron core segment 30, which is convenient for the fixed processing technology of 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 grooves opened in both of them, the gases will be transported along the corresponding directions.

[0060] Magnetic pole-hole collaborative design method for the rotor iron core cooling three-stage ventilation self-driven flow channel 31: Assume the number of arc-shaped special-shaped holes is (In this embodiment ), which are evenly distributed circumferentially (assuming that each hole corresponds to each pole in the motor technology). 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 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 speed 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.

[0061] (2) Magnetic pole cooling three-stage back-gap self-driven flow channel 32 - Magnetic pole thermal stress decoupling design method: The number of the magnetic pole cooling three-stage back-gap self-driven flow channels 32 is (guarantee , in this embodiment, take 2). The three - stage back - clearance self - driving flow channel 32 for pole cooling is a special - shaped hole, approximately half of an ellipse. The length of the major axis of the cross - section is (unit: mm), the length of the minor axis is (unit: mm), the absolute length of the special - shaped hole is (unit: mm), the angular velocity is (unit: rad / s), the twist angle is , and the expected boosting capacity 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 pole back - clearance is reduced.

[0062] The working principle of the present invention is as follows: Since the motor has a periodic symmetric structure, the upper cross - section is selected to illustrate the internal flow and heat dissipation of the motor, as shown in Figure 7 . Assume that the ambient 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 temperature at the near - wall surfaces of the three is also T 0 .

[0063] For the cooling process inside the rotor self - driving heat dissipation structure 3: The front - end boosting gas 1105 is pressurized and accelerated by the rotor core cooling first - stage boosting part 110 and ejected from the front - end boosting spray ring 1104, driving the confluence of the large - volume front - end gas 1106 to form the front - end injection gas 1112 of the rotor core cooling three - stage ventilation self - driving flow channel 31. At this time, the gas temperature is T 1 . As the rotor rotates, the injection gas 1112 takes away the heat inside the rotor self - driving heat dissipation structure 3 and is ejected as the hot gas 2121 with a temperature of T 4 , and then flows axially to the rear end cover 11 for cooling.

[0064] For the back - clearance cooling process between the rotor self - driving heat dissipation structure 3 and the pole 4: The rear - end boosting gas 2104 is pressurized and accelerated by the pole cooling first - stage boosting part 210 and ejected from the rear - end boosting 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 stator winding end 8 is inhaled. The two types of gases converge to form the rear - end injection gas 2113 of the rotor pole cooling three - stage back - clearance self - driving flow channel 32. At this time, the gas temperature is T 2 . As the rotor rotates, the rear - end injection gas 2113 takes away the heat between the pole 4 and the rotor self - driving heat dissipation structure 3 and becomes a temperature ofT 4 The heated gas 1131 then flows axially and is then radially ejected to accelerate the flow rate of the gas on the surface of the end portion 8 of the stator winding and cool it, forming a gas at a temperature of T 6 The hotter gas 81 flows towards the wall surface of the housing 9 for cooling.

[0065] Embodiment 2: This embodiment discloses a motor that uses the motor rotor cooling structure of Embodiment 1.

[0066] 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, an end portion 8 of the stator winding, a housing 9, a front end cover 10, and a rear end cover 11.

[0067] 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 machine 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 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.

[0068] 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, and any modification or partial replacement without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

[0069] If terms such as "first" and "second" are used in this article to limit components, those skilled in the art should be aware that the use of "first" and "second" is only for the convenience of describing the present invention and simplifying the description. Without additional statements, the above terms have no special meanings.

[0070] 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 therefore should not be construed as a limitation to the present invention.

[0071] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" 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 communication inside 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 circumstances.

Claims

1. A motor rotor cooling structure, including a rotating shaft, characterized in that: Axially fixed on the rotating shaft in sequence are a front-end drive structure, a middle 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 supercharging 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 pole; The rear-end drive structure includes a first-stage supercharging part for pole cooling, a second-stage drainage part for pole cooling, and a fourth-stage pressure relief flow channel for rotor core; The first-stage supercharging 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 connected in sequence, and the gas flow direction is from front to back; The first-stage supercharging part for pole cooling, the second-stage drainage part for pole cooling, the third-stage back-gap self-driven flow channel for pole cooling, and the fourth-stage pressure relief flow channel for pole cooling are connected in sequence, and the gas flow direction is from back to front.

2. The motor rotor cooling structure according to claim 1, wherein: The first-stage supercharging part for rotor core cooling includes a front-end hub and a front-end rim arranged in concentric circles. Front-end blades are provided between the front-end hub and the front-end rim. A front-end tapered flow channel is provided at the rear position of the front-end rim. The inner diameter of the front-end tapered flow channel gradually becomes smaller from front to back, and a front-end supercharging spray ring is formed between the small-diameter section of the front-end tapered flow channel and the front-end hub.

3. The motor rotor cooling structure according to claim 2, characterized in that: The second-stage drainage part for rotor core cooling includes a front-end gas main input channel and a front-end airfoil curved wall flow channel; There is a radial gap between the front-end hub and the rotating shaft, forming a front-end gas main input channel; The front-end tapered flow channel is connected to the front-end airfoil curved wall flow channel at the back, and the high-speed gas ejected from the front-end supercharging spray ring sprays at the front-end airfoil curved wall flow channel; The front-end gas main input channel is connected to the front end of the front-end airfoil curved wall flow channel, and the rear end of the front-end airfoil curved wall flow channel is connected to the front end of the third-stage ventilation self-driven flow channel for rotor core cooling.

4. The motor rotor cooling structure according to claim 3, characterized in that: The fourth-stage pressure relief flow channel for pole cooling is located radially outside the front-end airfoil curved wall flow channel, and the fourth-stage pressure relief flow channel for pole cooling is gradually widened as a whole along the gas flow direction; There is an axial gap between the front end of the fourth-stage pressure relief flow channel for pole cooling and the front-end rim, and it cooperates with the outer wall surface of the front-end tapered flow channel to form a wall surface gas outlet, and the wall surface gas outlet corresponds to the end part of the stator winding at the front end; The rear end of the fourth-stage pressure relief flow channel for pole cooling is connected to the front end of the third-stage back-gap self-driven flow channel for pole cooling.

5. The motor rotor cooling structure according to claim 1, characterized in that: The first-stage supercharging part for pole cooling includes a rear-end hub and a rear-end rim arranged in concentric circles. Rear-end blades are provided between the rear-end hub and the rear-end rim. The rear-end rim is connected to a rear-end tapered flow channel at the front. The inner diameter of the rear-end tapered flow channel gradually becomes smaller from back 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.

6. The motor rotor cooling structure according to claim 5, characterized in that: The second-stage drainage part for pole cooling includes a rear-end airfoil curved wall flow channel; A rear-end airfoil curved wall flow channel is provided at the front position of the rear-end tapered flow channel, and the high-speed gas ejected from the rear-end supercharging spray ring sprays at 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 pole cooling; There is an axial gap between the rear end of the rear wing-shaped 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 gas inlet, and the wall gas inlet corresponds to the end of the stator winding at the rear end.

7. The motor rotor cooling structure according to claim 6, wherein: 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; 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.

8. The motor rotor cooling structure according to claim 1, wherein: The components of the front-end drive structure / rear-end drive structure are connected respectively by circumferentially distributed support columns between them radially and between the front-end drive structure / rear-end drive structure and the rotating shaft. The support columns have a diamond cross-section.

9. The motor rotor cooling structure according to claim 1, characterized in that: The rotor core is divided into multiple core segments, and each core segment is laminated with silicon steel sheet punches at an angle, 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 axis to generate an axial thrust on the gas.

10. A motor, characterized in that: It includes the motor rotor cooling structure according to any one of claims 1-9. 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, and the rear-end drive structure is close to the rear end cover. The outer sides of the machine shell, the front end cover and the rear end cover all have heat dissipation structures.

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