High-speed air suspension compressor for fuel cells with sealed stator, fuel cell system and vehicle

Abstract

The high-speed air suspension compressor for fuel cells with sealed stator, fuel cell system and vehicle belongs to the technical field of hydrogen fuel cell electric drive air compressor. It solves the problems of traditional compressors, such as low rotation speed and poor cooling effect. Key points: The motor stator is a sealed stator, and both sides adopt resin or metal caps to seal the end coils, the cooling jacket is tightly fitted between the outer wall of the motor stator and the inner wall of the motor housing, the cooling passage communicates with the coolant inlet and outlet, the thrust disk is installed in the middle of the air suspension thrust bearing assembly, the steam seal body fixed to the motor rotor on the rear side of the impeller is placed on the outer edge of the back plate of the impeller, the cooling fan is fixed to the rear end of the rotor, and the rotor drives the cooling fan to blow air into the cavity in the motor stator and discharge it from the exhaust port. In the present invention, the cooling liquid flows through the cooling passage to remove heat from the stator, and the rotor is cooled by air flowing through the gap between the stator and rotor. The two cooling methods work together to ensure that the motor operates normally even under extreme conditions.

Description

[Technical Field]

[0001] The present invention relates to a compressor for a fuel cell, a fuel cell system and a vehicle, and more particularly to a high-speed air suspension compressor for a fuel cell with a sealed stator, a fuel cell system and a vehicle, which belongs to the technical field of hydrogen fuel cell electric-powered air compressors. [Background technology]

[0002] In terms of new energy, automobiles powered by hydrogen fuel cells have high power performance, fast hydrogen refueling, and long driving range, making them a breakthrough of strategic importance for new energy automobiles in the 21st century. Hydrogen fuel cells directly output electrical energy through a chemical reaction between hydrogen and oxygen gas, and the power density of a hydrogen fuel cell is directly related to the supply pressure and supply flow rate of the air supply system; the higher the supply pressure and the higher the partial pressure of oxygen gas, the faster the fuel cell reaction rate and the greater the output power.

[0003] In fuel cell stack applications, an air compressor is used to output compressed air to the stack for hydrogen-oxygen reaction to generate electricity. In the prior art, a commonly used technical solution is to use air to cool the motor stator, but the cooling effect is not ideal, or to use liquid to cool the motor stator, and arrange a cooling passage inside the motor case to cool the motor case and achieve the effect of lowering the temperature of the motor stator. In the prior art, there are air cooling for cooling the rotor and liquid cooling for cooling the stator, but the structural designs are different. Sometimes the rotor is cooled by the bleed air from the compressor volute casing, but the temperature of the air after compression is relatively high and the cooling effect is poor. The bleed air temperature itself is high, and after being used to cool the air bearing, the temperature continues to rise and is then used to cool the motor rotor, resulting in a clearly insufficient cooling capacity. Sometimes the bleed air is first passed through the motor housing after being bled, and the liquid cooling capacity is used to reduce the bleed air temperature before being introduced into the motor to cool the motor rotor. This requires consideration of the length of the cooling passage in the motor casing, whether the cooling passage is as close to the motor stator as possible, and specific implementation issues such as whether the coils on both sides of the motor stator can be sufficiently cooled. The cooling effect is unclear. Increasing the cooling air volume increases power consumption, and the discharge of a large amount of heated air accumulates heat in the external environment of the air compressor.

[0004] When using air compressors in fuel cells, due to the size and weight requirements of automotive components, the design of the air compressor must maximize energy density while reducing its volume and weight. This requires a compact motor design, high rotational speeds (over 100,000 rpm), and high windage loss in the gap between the stator and rotor (proportional to the rotational speed), which poses a potential risk of motor overheating. Therefore, conventional water cooling is generally used to cool the motor stator, which involves arranging cooling passages in the motor case and using metal heat transfer to remove heat from the stator. However, this type of cooling has another problem: it does not provide a good cooling effect on both sides of the stator.

[0005] Prior art 1, disclosure number CN 213953927 In a patent for a centrifugal compressor, the air cooling flow path has an external pressure source that flows perpendicular to the circumferential surface of the thrust disk outer diameter of the thrust bearing. When the thrust disk rotates at high speed, the air rushes perpendicular to the circumferential surface of the thrust disk outer diameter, causing instability in the operation of the thrust bearing. The axial thrust generated by the impeller on one side itself increases or worsens the effect of the unidirectional axial thrust. The patent specification discloses two-stage compression and single-stage compression, but there are two-stage compression impellers on both sides, and the thrust of the left and right bearings cancel each other out. The design simply removes one of the impellers and changes to a single-stage compression, but does not take into account the adverse effects of the increased axial thrust caused by this change. This creates a significant instability in the operation of the air foil bearing and poses a potential risk of wear and burnout of the thrust bearing, resulting in damage to the internal structure of the motor. Furthermore, in the single-stage design of this patent, the intake position is near the rear back plate of the impeller, close to the thrust disk, and the temperature at this position is relatively high. After the air enters, part of the air is heated and flows from the impeller side through the rotor to the rear of the motor away from the impeller, cooling the outflow air bearing there. Then, at the rear end, it enters the passage of the motor housing and is discharged after being cooled. However, there is a potential risk that the rotor and the radial bearing away from the impeller will not be sufficiently cooled. In addition, the flow path design allows the air to pass from the impeller end through the motor to the rear end, flow radially toward the housing at the rear end, and then pass through the motor housing again from the rear end of the housing to be discharged near the impeller side. However, the flow path design is complicated and cannot guarantee a smooth reduction in pressure stages, and there are problems with ensuring the flow velocity and volume.

[0006] Prior Art 2, the patent with disclosure number CN 213717784 U and disclosure date 2021.07.16, entitled "A cooling system for a two-stage air suspension centrifugal permanent magnet motor directly driven air compressor," places the stator liquid cooling passage at the outermost part of the motor case, and also adds a cooling air passage in the middle (which discharges the recovered air after cooling), resulting in a serious lack of cooling capacity for the stator and stator coil. Stator cooling is the most important design feature of a high-speed motor, and this design does not distinguish between primary and secondary, preventing the motor from operating for long periods of time, especially when the external environmental temperature is high and conditions are poor, posing significant risks and significantly affecting the motor's lifespan.

[0007] To sum up, in order to overcome the problems in the prior art that the rotation speed of the compressor is low and the cooling effect is not ideal, the cooling method and structure of the compressor need to be improved.

[0008] It should be explained that the information disclosed in the Background of the Invention section is merely intended to enhance understanding of the general background of the present invention and should not be taken as an admission or in any way implying that this information constitutes prior art already known to those skilled in the art. Summary of the Invention [Problem to be solved by the invention]

[0009] In view of the above facts, the present invention aims to design a high-speed air suspension compressor for fuel cells, a fuel cell system and a vehicle, which further has a sealed stator, in order to overcome the problems of the conventional compressor, such as low rotation speed and poor cooling effect. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention adopts the following technical solution.

[0011] Aspect 1: A high-speed air suspension compressor for a fuel cell having a sealed stator, comprising: a motor housing having a coolant inlet and a coolant outlet and an air outlet formed at a front end thereof; a motor stator and a motor rotor installed in the motor housing, the motor rotor being inserted into a cavity in the motor stator and freely rotating, the front and rear ends of the motor rotor being connected to the motor housing via air suspension bearing assemblies, the motor stator being a sealed stator, and both sides of the motor stator employing resin or metal caps to seal the end coils; a cooling jacket attached by an interference fit between an outer wall of the motor stator and an inner wall of the motor housing, the cooling jacket having cooling passages formed in the outer wall thereof, the cooling passages communicating with a coolant inlet and a coolant outlet; a volute casing and an impeller, the impeller being positioned within the volute casing, the root of the impeller tightly engaging a thrust disk, and the impeller being fixed to a forward end of the motor rotor; a steam seal body located at the outer edge of the impeller back plate, and a thrust disk located between the air suspension thrust bearing assembly and fixed to the motor rotor behind the impeller; and a cooling fan secured to the rear end of the motor rotor, the motor rotor driving the cooling fan to force air into a cavity in the motor stator and out through an air outlet.

[0012] In connection with Aspect 1, in some implementations of Aspect 1, the air suspension bearing assembly includes a front bearing holder, a rear bearing holder, a rear air suspension radial bearing, and a front air suspension radial bearing, the front bearing holder and the rear bearing holder are sealedly attached to the front and rear ends of the motor housing, the front end of the motor rotor is connected to the front bearing holder via the front air suspension radial bearing, and the rear end of the motor rotor is connected to the rear bearing holder via the rear air suspension radial bearing, an air passage is opened in the rear bearing holder, and a cooling fan blows air through the air passage into a cavity in the motor stator.

[0013] In connection with embodiment 1, in some implementations of embodiment 1, the high-speed air suspension compressor for a fuel cell having a sealed stator further includes a motor rear cover, and the cooling fan is packaged in the rear bearing holder through the motor rear cover.

[0014] In connection with the first embodiment, in some implementations of the first embodiment, the cooling fan is fixed to the rear end of the motor rotor via a rear tension bolt.

[0015] In connection with Aspect 1, in some implementations of Aspect 1, the air suspension thrust bearing assembly includes a thrust bearing holder, an outer thrust bearing, and an inner thrust bearing, the thrust bearing holder is connected to the front bearing holder, and the outer thrust bearing, thrust disk, and inner thrust bearing are installed between the thrust bearing holder and the front bearing holder in order from front to rear, a steam seal is installed between the impeller and the thrust bearing holder, and the impeller, thrust disk, and motor rotor are coaxially connected via a front tension bolt, and compressed air flows through the steam seal to cool the thrust bearing.

[0016] Furthermore, the coolant may be other liquids such as ethylene glycol, a mixture of ethylene glycol and water, deionized water, oil, etc. In this embodiment, no additional equipment is required, and the vehicle coolant can be directly used as the cooling medium for the motor, further reducing the weight and volume of the device.

[0017] Furthermore, the cooling passage is a spiral cooling passage.

[0018] Furthermore, the air discharge ports are plural and are uniformly spaced along the circumferential direction of the motor housing.

[0019] Furthermore, there are two air exhaust ports, which are arranged above and below the motor housing.

[0020] Furthermore, there are four air exhaust ports, which are arranged at 90-degree intervals on the motor housing.

[0021] Furthermore, there are 12 air outlets, which are arranged at 30-degree intervals on the motor housing.

[0022] Various arrangements of the air outlet can be easily selected by the automobile manufacturer, or can be appropriately adjusted according to the automobile manufacturer's requirements, and the exhaust gas is connected to the automobile exhaust gas exhaust pipe through a pipe.

[0023] Aspect 2: According to another aspect of the invention, there is further provided a fuel cell system including the high-speed air suspension compressor according to aspect 1.

[0024] Aspect 3: According to another aspect of the present invention, there is provided a vehicle including the high-speed air suspension compressor according to Aspect 1 or the fuel cell system according to Aspect 2. [Effects of the Invention]

[0025] The effects achieved by the present invention are as follows:

[0026] 1. In this invention, the cooling liquid (ethylene glycol, a mixture of ethylene glycol and water, oil, or other liquids) flows through the cooling passage to remove heat from the stator, and the rotor is cooled by air flowing through the gap between the stator and rotor. The two cooling methods work together with obvious effects, which can better ensure the normal operation of the motor under extreme conditions.

[0027] 2. To ensure that sufficient cooling air flows through the air bearing and the gap between the rotor and stator, a steam seal is designed on the back of the impeller to allow some compressed air to leak into the motor, and a coaxial cooling fan is designed on the side away from the impeller so that the air drawn in from outside can flow through the entire gap between the stator and rotor, thereby achieving the effect of cooling the radial bearing and motor rotor on the side away from the impeller.

[0028] 3. A new type of stator is adopted, with both sides of the stator sealed with resin or metal caps, sealing the coil and cooling the entire outer surface of the stator, greatly improving the length of the cooling passage. Specifically, this example adopts a sealed stator with a long cooling passage. The application of the sealed stator in the field of fuel cells is the invention of this invention. In the stator structure of the prior art, only the middle part (silicon steel plate) is tightly fitted with the housing or sleeve to achieve physical contact. In this application, there is full physical contact, achieving a long cooling passage and good cooling effect.

[0029] 4. The present invention has a high rotation speed (150,000 rpm) and can achieve a pressure ratio of 1:3 with one-stage compression.

[0030] 5. The compressor of the present invention is small in size, has a high rotational speed, and has a high energy density, and is only one-third or one-half the size of the compressor of the prior art 1, and weighs half or even less. [Brief explanation of the drawings]

[0031] [Figure 1]1 is an assembly diagram of a high-speed air suspension compressor for a fuel cell having a sealed stator according to a first embodiment. FIG. [Figure 2] FIG. 10 is an assembly diagram of a high-speed air suspension compressor for a fuel cell having a sealed stator according to a second embodiment. [Figure 3] 1 is a schematic diagram of the cooling medium flow of a high-speed air suspension compressor for a fuel cell with a sealed stator according to the present invention. FIG. [Figure 4-1] This is a temperature distribution (3D solid model) diagram of a 16kW fuel cell air compressor with an inlet mass flow rate of 13 g / s. [Figure 4-2] This is a temperature distribution (3D solid model) diagram of a 16kW fuel cell air compressor with an inlet mass flow rate of 8 g / s. [Figure 5-1] This is a pressure distribution diagram of a 16kW fuel cell air compressor fluid (ethylene glycol + water, air) with an inlet mass flow rate of 13 g / s. [Figure 5-2] This is a pressure distribution diagram of a 16kW fuel cell air compressor fluid (ethylene glycol + water, air) with an inlet mass flow rate of 8 g / s. [Figure 6-1] This is a temperature distribution diagram of a 16kW fuel cell air compressor fluid (ethylene glycol + water, air) with an inlet mass flow rate of 13 g / s. [Figure 6-2] This is a temperature distribution diagram of a 16kW fuel cell air compressor fluid (ethylene glycol + water, air) with an inlet mass flow rate of 8 g / s. DETAILED DESCRIPTION OF THE INVENTION

[0032] In order to help those skilled in the art to better understand the aspects of the present application, the following clearly and completely describes the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application, and obviously, the described embodiments are only some of the embodiments of the present application, and do not represent all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without any creative efforts shall fall within the protection scope of the present application.

[0033] It should be noted that the terms "first," "second," etc. in the specification and claims of this application and in the drawings are used to distinguish between similar objects and are not necessarily used to describe a particular order or sequence of steps. It should be understood that terms used in this manner are interchangeable where appropriate for the embodiments of this application described herein. It should be noted that the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive "comprises," e.g., a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may also include other steps or units not explicitly listed or inherent in the process, method, product, or apparatus.

[0034] In this application, the orientations or positional relationships indicated by terms such as "upper," "lower," "inner," "middle," "outer," "front," and "rear" are orientations or positional relationships shown in the drawings. These terms are primarily intended to better describe this application and its embodiments, and are not intended to limit the indicated devices, elements, or components to have a specific orientation or to be constructed and operated in a specific orientation. Some of the above terms may be used to express other meanings in addition to indicating orientations or positional relationships. For example, the term "upper" may also be used to express a certain dependency or connection relationship in some cases. Those skilled in the art will be able to understand the specific meanings of these terms in this application depending on the specific circumstances.

[0035] The terms "installed," "connected," and "fixed" should be understood in a broad sense. For example, "connected" may refer to a fixed connection, a detachable connection, or an entire structure, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, or an internal communication between two devices, elements, or components. Those skilled in the art can understand the specific meanings of the above terms in this application according to specific circumstances.

[0036] It should be noted that, unless conflicting, the embodiments and features in the embodiments in the present application can be combined with each other. The following describes the present application in detail in conjunction with the embodiments with reference to the drawings.

[0037] In the following, preferred embodiments of the invention will be described in detail with reference to the drawings.

[0038] Embodiment 1: Referring to FIG. 1, the high-speed air suspension compressor for fuel cells with a sealed stator of this embodiment includes a rear bearing holder 1, a motor mount 2, a rear air suspension radial bearing 3, a motor housing 4, a motor stator 5, a motor rotor 6, a front bearing holder 8, a volute casing 9, an impeller 10, a front tension bolt 12, a thrust disk 13, an inner thrust bearing 14, a steam seal body 15, a front air suspension radial bearing 17, a cooling jacket 19, a motor rear cover 21, a rear tension bolt 22, a cooling fan 23, a bearing holder 24, and an outer thrust bearing 25; The motor housing 4 is attached to the motor mount 2, and the motor housing 4 is provided with a coolant inlet 18 and a coolant outlet 20, and pipe joints are provided at the coolant inlet 18 and the coolant outlet 20. Two air outlets 7, one at the top and one at the bottom, are formed at the front end of the motor housing 4. The motor stator 5 is a sealed stator, and both sides of the motor stator are fitted with resin or metal caps to seal the end coils. The motor stator 5 and the motor rotor 6 are both installed in the motor housing 4. The motor rotor 6 is inserted into a cavity in the motor stator 5 and rotates freely. The front bearing holder 8 and the rear bearing holder 1 are sealed and attached to the front and rear ends of the motor housing 4. The front end of the motor rotor 6 is connected to the front bearing holder 8 via a front air suspension radial bearing 17, and the rear end of the motor rotor 6 is The end of the motor rotor 6 is connected to the rear bearing holder 1 via the rear air suspension radial bearing 3, and the rear bearing holder 1 has an annularly arranged air passage 1-1. The cooling fan 23 is fixed to the rear end of the motor rotor 6 via a rear tension bolt 22 and packaged within the rear bearing holder 1 (the rear bearing holder 1 has a fan mounting space) via a motor rear cover 21. The motor rotor 6 drives the cooling fan 23 to send air through the air passage 1-1 into the cavity within the motor stator 5 and discharge it through the air outlet 7. The cooling jacket 19 is attached by interference fit between the outer wall of the motor stator 5 and the inner wall of the motor housing 4, and the outer wall of the cooling jacket 19 is machined with a spiral cooling passage 19-1 communicating with a coolant inlet 18 and a coolant outlet 20. The impeller 10 is placed in the volute casing 9 and is connected to the front end of the motor rotor 6 in a rotational coupling manner. The front end of the volute casing 9 is the intake port 11, and the inside is the compressed air flow path 16. The thrust bearing holder 24 is connected to the front bearing holder 8, and the thrust Between the impeller 10 and the thrust bearing holder 24 and the front bearing holder 8, an outer thrust bearing 25, a thrust disk 13, and an inner thrust bearing 14 are installed in this order from front to rear. A steam seal 15 is installed between the impeller 10 and the thrust bearing holder 24. The impeller 10, the thrust disk 13, and the motor rotor 6 are coaxially connected via a front tension bolt 12. Compressed air flows through the steam seal 15 to cool the thrust bearing. The coolant is ethylene glycol.

[0039] Compared with prior art 1, this embodiment adopts a new type of stator, sealing both sides of the stator with resin or metal caps, sealing the coil, and cooling the entire outer surface of the stator, greatly improving the length of the cooling passage. Specifically, this embodiment adopts a sealed stator with a long cooling passage. The application of the sealed stator in the field of fuel cells is the invention of the present invention. In the stator structure of the prior art, the middle part (silicon steel plate) is only tightly fitted with the housing or sleeve to achieve physical contact, but this application uses full physical contact, achieving a long cooling passage and good cooling effect. Two-stage compression requires a complex structure and a complex cooling passage design, and a high compression ratio can only be achieved through two-stage compression without increasing the rotational speed. This embodiment has a high rotational speed (150,000 rpm) and can achieve a pressure ratio of 1:3 with single-stage compression. Furthermore, by changing the cooling passage and structure, this compressor is small in size, has a high rotational speed, and has a high energy density, and is only one-third or one-half the size and half the weight of the conventional technology. The motor stator of this embodiment uses liquid flowing through the cooling passage to remove heat from the stator, and the rotor is cooled by air flowing through the gap between the stator and rotor. The two cooling methods work together, producing a clear effect and better ensuring normal operation of the motor under extreme conditions. To ensure that sufficient cooling air flows through the air bearing and the gap between the rotor and stator, a steam seal is also designed on the backside of the impeller to allow some compressed air to leak into the motor. A coaxial cooling fan is designed on the side away from the impeller, allowing the air drawn in from outside to flow through the entire gap between the stator and rotor, thereby achieving the effect of cooling the radial bearing and motor rotor on the side away from the impeller.An air suspension thrust bearing is arranged behind the impeller, and air suspension radial bearings are arranged on both the left and right sides of the motor, away from the coaxial cooling fan on the impeller side. The steam seal behind the impeller, the flow direction of the air cooling, the amount of air leaking on the impeller side flows into the inside of the motor, the rear cover is away from the impeller side, the cooling fan draws in air and flows into the motor, and after the two meet, it is discharged from the motor, and the liquid cooling passage extends as far as possible on both sides to increase the cooling area.

[0040] Embodiment 2: Referring to FIG. 2, this embodiment differs from embodiment 1 in that there are 12 air outlets 7 arranged at intervals of 30 degrees on the motor housing 4.

[0041] Example 3: The difference from the above Example 1 or 2 is that the cooling liquid is a mixture of ethylene glycol and water.

[0042] Example 4: The difference from the above Example 1 or 2 is that the cooling liquid is oil.

[0043] Example 5: This example further provides a fuel cell system including the high speed air suspension compressor of any one of Examples 1-4.

[0044] Example 6: Another aspect of this example provides a vehicle including the high speed air suspension compressor according to any one of Examples 1-4 or the fuel cell system according to Example 5.

[0045] The cooling simulation test of the present invention is as follows.

[0046] 1.Motor material attributes: [Table 1] *The simulation uses 1.5 times the normal power consumption of the bearings (1.5×Bearing losses are applied).

[0047] 2. Input conditions for cooling flow rate (liquid cooling and gas cooling) for simulation calculation: Ethylene glycol-water mixture: turbulent flow Density @20oC: 1,087 kg / m 3 Thermal conductivity: 0.37 W / m K Specific heat: 3,285 J / kg K Dynamic viscosity: 0.0038 Pa·s Inlet mass flow rate: 100 g / s Inlet static temperature: 45oC Outlet conditions: standard atmospheric pressure (101,325 Pa) Air fluid leaking from the back end of the compressor impeller: Inlet mass flow rate: 2.5 g / s Inlet static temperature: 140oC Air fluid drawn in by the cooling fan away from the impeller end (two cases of flow rate magnitude were calculated): Inlet mass flow rate: 13 g / s (Case 1), 8 g / s (Case 2) Inlet static temperature: 45oC Rotor speed: 150,000 rpm

[0048] 3. Result data and images: [Table 2]

[0049] For the temperature distribution calculated by simulation of the 3D solid component, see Figures 4-1 and 4-2. For the pressure distribution calculated by simulation of the cooling fluid (ethylene glycol + water, air), see Figures 5-1 and 5-2. For the temperature distribution calculated by simulation of the cooling fluid (ethylene glycol + water, air), see Figures 6-1 and 6-2.

[0050] Summary of simulation results: The internal thermodynamic model of a high-speed motor was simulated by setting input conditions for a case where the power consumption of a normal air bearing is 1.5 times that of a normal air bearing (simulating a harsh operating condition). The input conditions were set to model the air suspension radial bearing and the air suspension thrust bearing, which both generate approximately 150% of the heat that they would generate under normal operating conditions (the power consumption of the bearings is the heat generated, which can be considered an extremely harsh operating condition). The simulation results verified that the temperature and pressure of the fluid in the liquid cooling and air cooling passages of this invention were achieved, achieving very good control of the motor's internal temperature, meeting the motor's cooling requirements, and ensuring normal operation of the motor. When the motor's liquid cooling conditions and the cooling airflow rate leaking from the steam seal at the rear end of the impeller remain unchanged, the simulation calculates the temperature distribution of the 3D solid part when the cooling fan provides cooling airflow rates of 13 g / s and 8 g / s, respectively, to the cooling fan away from the impeller end (the right end of the motor in the diagram). Comparing the calculation results and temperature distribution diagrams for Case 1 and Case 2, it can be seen that the use of a sealed stator extends the liquid cooling passages and improves the heat dissipation capacity of the stator end, allowing most of the heat to be absorbed by the liquid cooling passages, effectively alleviating the heat dissipation pressure in the air cooling passages. With this design, even with a cooling fan providing only an 8 g / s flow rate, an extremely low temperature distribution can be maintained inside the entire motor. The low temperatures of the motor shaft and permanent magnets can ensure the motor's operating efficiency and operating life, and are one of the most important indicators for evaluating cooling effectiveness. The cooling air for the air suspension thrust bearing and radial bearing (impeller side) comes from the leaking air of the steam seal, so the inlet temperature is already 140°C. After cooling the air bearing with 1.5 times the power consumption, the temperature rises to 235°C. The bearing itself has the ability to withstand high temperatures of up to 400°C. The simulation results show that the bearing can withstand even harsher operating environments, and even with 1.5 times the normal power consumption, there is a large safety margin before the bearing temperature reaches its upper limit.

[0051] The above examples are only used to explain the technical solutions of the present invention, and are not intended to limit the same. Although the present invention has been described in detail with reference to the above examples, those skilled in the art may still modify the technical solutions described in the above examples or replace some or all of the technical features therein with equivalents, but it should be understood that such modifications or replacements do not cause the essence of the corresponding technical solutions to depart from the scope of the technical solutions of the embodiments of the present invention.

[0052] It should be understood that this specification is described according to embodiments, but each embodiment does not include only one independent technical solution, and such description of the specification is for the sake of clarity only, and those skilled in the art should treat the specification as a whole, and the technical solutions in each example can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. [Explanation of symbols]

[0053] 1 Rear bearing holder 2 motor mounts 3 Rear air suspension radial bearings 4 Motor housing 5 Motor stator 6 Motor rotor 7 Air outlet 8 Front bearing holder 9. Spiral casing 10 impeller 11 Air intake 12 Front tension bolt 13 Thrust disc 14 Inner thrust bearing 15 Steam seal body 16 compressed air flow path 17 Front air suspension radial bearing 18 Coolant inlet 19 Cooling jacket 20 Coolant outlet 21 Motor rear cover 22 Rear tension bolt 23 Cooling fan 24 Bearing holder 25 outer thrust bearing

Claims

1. A high speed air suspension compressor for a fuel cell having a sealed stator, comprising: a motor housing (4) in which a coolant inlet (18) and a coolant outlet (20) are provided, and an air exhaust port (7) is formed on the front end side of the coolant inlet (18); a motor stator (5) and a motor rotor (6) installed in the motor housing (4), the motor rotor (6) being inserted into a cavity inside the motor stator (5) and rotating freely, the front and rear ends of the motor rotor (6) being connected to the motor housing (4) via air suspension bearing assemblies, the motor stator (5) being a sealed stator, and both sides of the motor stator employing resin or metal caps to seal the end coils; a cooling jacket (19) attached by an interference fit between an outer wall of the motor stator (5) and an inner wall of the motor housing (4), the cooling jacket (19) having a cooling passage (19-1) formed in the outer wall thereof, the cooling passage (19-1) communicating with a coolant inlet (18) and a coolant outlet (20); a volute casing (9) and an impeller (10), the impeller (10) being placed in the volute casing (9), the root of the impeller (10) being tightly engaged with a thrust disk (13), and the impeller (10) being fixed to the front end of the motor rotor (6); a steam seal body (15) placed on the outer edge of the back plate of the impeller (10), and a thrust disk (13) installed in the middle of the air suspension thrust bearing assembly and fixed to the motor rotor (6) behind the impeller (10); a cooling fan (23) fixed to the rear end of the motor rotor (6), the motor rotor (6) driving the cooling fan (23) to send air into a cavity inside the motor stator (5) and discharge the air from an air outlet (7); The air suspension bearing assembly includes: a front bearing holder (8) provided on the front end side of the motor housing (4); a front air suspension radial bearing (17) provided on the inner periphery side of the front bearing holder (8); an annular rear bearing holder (1) provided on the rear end side of the motor housing (4); a rear air suspension radial bearing (3) provided on the inner periphery of the rear bearing holder (1) so as to be connected to the rear bearing holder (1); The motor rotor (6) has a front end connected to the front bearing holder (8) via the front air suspension radial bearing (17), and a rear end connected to the rear bearing holder (1) via the rear air suspension radial bearing (3), an air passage (1-1) is formed at a location closer to the inner peripheral edge than the outer peripheral edge of the rear bearing holder (1), the air passage (1-1) communicating with a cavity inside the motor stator (5) and a cooling fan accommodating cavity in which the cooling fan (23) is accommodated, and penetrating the rear bearing holder (1) along the axial direction of the rear bearing holder (1); A flow path is formed between the front bearing holder (8) and the front air suspension radial bearing (17), which connects a cavity inside the motor stator (5) with an impeller-accommodating cavity in which the impeller (10) is accommodated; A communication flow path is formed between the front bearing holder (8) and the front end surface of the motor stator (5), which communicates the air exhaust port (7) with a cavity inside the motor stator (5). A high-speed air suspension compressor for a fuel cell having a sealed stator.

2. 2. The high-speed air suspension compressor for fuel cells having a sealed stator according to claim 1, further comprising a motor rear cover (21), wherein the cooling fan (23) is packaged in the rear bearing holder (1) through the motor rear cover (21).

3. 2. The high-speed air suspension compressor for a fuel cell with a sealed stator according to claim 1, wherein the cooling fan (23) is fixed to the rear end of the motor rotor (6) via a rear tension bolt (22).

4. 2. The high-speed air suspension compressor for fuel cells with a sealed stator according to claim 1, wherein the air suspension thrust bearing assembly includes a thrust bearing holder (24), an outer thrust bearing (25), and an inner thrust bearing (14), the thrust bearing holder (24) is connected to the front bearing holder (8), and the outer thrust bearing (25), thrust disk (13), and inner thrust bearing (14) are installed between the thrust bearing holder (24) and the front bearing holder (8) in this order from front to rear, a steam seal (15) is installed between the impeller (10) and the thrust bearing holder (24), and the impeller (10), thrust disk (13), and motor rotor (6) are coaxially connected via a front tension bolt (12), and compressed air passes through the steam seal (15) to cool the thrust bearing.

5. 5. The high-speed air suspension compressor for fuel cells with a sealed stator as claimed in claim 4, wherein the coolant is ethylene glycol, a mixture of ethylene glycol and water, deionized water or oil.

6. The high-speed air suspension compressor for fuel cells with a sealed stator according to claim 3, characterized in that the cooling passage (19-1) is a spiral cooling passage.

7. The air exhaust ports (7) are plural and are uniformly opened along the circumferential direction of the motor housing (4), Alternatively, the air exhaust ports (7) are two in number and are arranged one above the other on the motor housing (4), Alternatively, the number of the air outlets (7) is four, and they are arranged at 90-degree intervals on the motor housing (4), Alternatively, the number of the air outlets (7) is 12, and the air outlets (7) are arranged at intervals of 30 degrees on the motor housing (4).

8. A fuel cell system comprising a high speed air suspension compressor for a fuel cell having the sealed stator of claim 1.

9. A vehicle comprising a high-speed air suspension compressor for a fuel cell having the sealed stator according to any one of claims 1 to 7 or a fuel cell system according to claim 8.

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