A structure for reducing axial thrust during operation of an air compressor

Abstract

The utility model relates to a structure for reducing the axial thrust during the operation of an air compressor. The utility model includes a mounting body, including a front cover, a compression shell mounted on the front cover, and a front end cover mounted between the front cover and the compression shell, wherein a bearing chamber is formed between the front cover and the front end cover; an impeller assembly, including a rotating shaft rotatably connected to the mounting body, a thrust plate and an impeller respectively mounted on the rotating shaft, the impeller being located between the compression shell and the front end cover, and the thrust plate being located in the bearing chamber; two thrust bearings, respectively mounted in the bearing chamber and located on both sides of the thrust plate in the axial direction; an acting body is mounted on one end of the front cover or the front end cover facing the thrust bearing, and the acting body can cause the thrust plate to be subjected to an axial magnetic attraction force, which is opposite to the axial force generated when the impeller rotates. The axial force generated by the pressure difference between the impeller wheel surface and the wheel back during the operation of an oil-free fuel cell air compressor can be reduced, the load that the thrust bearing needs to bear can be reduced, and the stability and reliability of high-speed operation can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of air compressor impeller systems, in particular to a structure for reducing the axial thrust of an air compressor when it is running. Background Art

[0002] Hydrogen fuel cell system power generation is a new way of energy utilization. It uses hydrogen and oxygen to react and generate electricity to drive the car. The exhaust is pure water, so the process can be completely environmentally friendly. The hydrogen fuel cell air compressor is a key component of the hydrogen fuel cell system, characterized by high efficiency, high speed, and oil-free. Hydrogen fuel cell air compressors generally use air bearings to support the rotor to achieve extremely high operating speeds and completely oil-free air supply. However, since air bearings use the principle of air dynamic pressure to form loads, the load capacity that can be provided will have an upper limit. This has the most significant impact on the thrust bearings arranged axially inside the air compressor.

[0003] When the impeller of a centrifugal rotating machine is running, the inlet end of the wheel surface will suck in fluid at a lower pressure. As the impeller rotates, the fluid will be accelerated and have a certain pressure. Therefore, a higher pressure will appear at the radial outlet position of the impeller. Since there is a certain gap between the rotating wheel back and the stationary front cover, and the wheel back gap is connected to the radial outlet, the wheel back gap space will be filled with high-pressure fluid, forming a pressure difference from the wheel back to the wheel surface direction with the low pressure at the impeller inlet, resulting in the generation of axial force. Under more extreme outlet flow, pressure conditions and different boosting forms (such as single-stage compressor boosting), the generated axial force can easily exceed the load range of the air-floating thrust bearing, resulting in collision of the moving and static parts of the rotor bearing system at high speed, resulting in serious consequences such as component damage. Therefore, it is urgent to propose improvement measures for this problem. Summary of the invention

[0004] To this end, the utility model provides a structure for reducing the axial thrust when the air compressor is running, which can reduce the axial force generated by the pressure difference between the impeller wheel surface and the wheel back when the oil-free fuel cell air compressor is running, reduce the load that the thrust bearing needs to bear, and improve the stability and reliability of high-speed operation.

[0005] In order to solve the above technical problems, the utility model provides a structure for reducing the axial thrust of an air compressor during operation, comprising:

[0006] The mounting body comprises a front cover, a compression shell mounted on the front cover, and a front end cover mounted between the front cover and the compression shell, wherein a bearing chamber is formed between the front cover and the front end cover;

[0007] An impeller assembly, comprising a rotating shaft rotatably connected to the mounting body, and a thrust plate and an impeller respectively mounted on the rotating shaft, wherein the impeller is located between the compression shell and the front end cover, and the thrust plate is located in the bearing chamber;

[0008] Two thrust bearings are respectively installed in the bearing chamber and located on both sides of the thrust plate;

[0009] Wherein, an actuator is installed at one end of the front cover or the front end cover facing the thrust bearing, and the actuator can cause the thrust plate to be subjected to an axial magnetic attraction, and the axial magnetic attraction is opposite to the axial force generated when the impeller rotates.

[0010] In one implementation of the utility model, the acting body is a permanent magnet, and the thrust plate is made of ferromagnetic material.

[0011] In one embodiment of the present invention, the active body includes neodymium iron boron, ferrite or samarium cobalt.

[0012] In one implementation of the present invention, a plurality of the acting bodies are evenly arranged circumferentially along the central axis of the rotating shaft.

[0013] In one embodiment of the present utility model, the front cover and / or the front end cover is provided with a groove capable of being engaged with the actuator at an end opposite to the thrust bearing.

[0014] In an embodiment of the present utility model, the two thrust bearings are respectively mounted on the end faces of the front cover and the front end cover.

[0015] In one implementation of the utility model, an adjustment gasket is provided between the thrust bearing and the acting body.

[0016] In one embodiment of the present invention, the thrust bearing is a gas foil bearing.

[0017] The above technical solution of the utility model has the following advantages compared with the prior art:

[0018] The utility model discloses a structure for reducing the axial thrust during operation of an air compressor, which generates an attraction to the thrust plate and generates an axial suction force in the opposite direction to that of the impeller during rotation, thereby offsetting or reducing the load borne by the thrust bearing. The utility model can reduce the axial force generated by the pressure difference between the impeller wheel surface and the wheel back during operation of an oil-free fuel cell air compressor, reduce the load that the thrust bearing needs to bear, and improve the stability and reliability of high-speed operation. The utility model has a simple structure and is easy to adjust. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the content of the utility model more clearly understood, the utility model is further described in detail below based on specific embodiments of the utility model in combination with the accompanying drawings.

[0020] Figure 1 The utility model is a cross-sectional schematic diagram of a structure for reducing the axial thrust of an air compressor when the air compressor is running.

[0021] Figure 2 It is a structural schematic diagram of the front cover of the utility model.

[0022] Description of the Figures in the Specification:

[0023] 1. Mounting body; 11. Front cover; 12. Pressure shell; 13. Front cover; 14. Bearing chamber; 15. Groove;

[0024] 2. impeller assembly; 21. rotating shaft; 22. thrust plate; 23. impeller;

[0025] 3. Thrust bearing;

[0026] 4. Affecting body. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0028] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0029] In the present utility model, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present utility model, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0030] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0031] Reference Figure 1 As shown, the utility model is a structure for reducing the axial thrust of the air compressor during operation, comprising:

[0032] The mounting body 1 comprises a front cover 11, a compression shell 12 mounted on the front cover 11, and a front end cover 13 mounted between the front cover 11 and the compression shell 12, wherein a bearing chamber 14 is formed between the front cover 11 and the front end cover 13;

[0033] The impeller assembly 2 comprises a rotating shaft 21 rotatably connected to the mounting body 1, and a thrust plate 22 and an impeller 23 respectively mounted on the rotating shaft 21, wherein the impeller 23 is located between the compression shell 12 and the front end cover 13, and the thrust plate 22 is located in the bearing chamber 14;

[0034] Two thrust bearings 3 are respectively installed in the bearing chamber 14 and located on both sides of the thrust plate 22 in the axial direction;

[0035] An actuator 4 is installed at one end of the front cover 11 or the front end cover 13 facing the thrust bearing 3, and the actuator 4 can subject the thrust plate 22 to an axial magnetic attraction force, which is opposite to the axial force generated when the impeller 23 rotates.

[0036] By generating attraction on the thrust plate 22 and generating an axial suction force in the opposite direction to the rotation of the impeller 23 , the load borne by the thrust bearing 3 is offset or reduced.

[0037] In one embodiment, the actuator 4 is a permanent magnet, and the thrust plate 22 is made of ferromagnetic material. Optionally, the actuator 4 includes neodymium iron boron, ferrite or samarium cobalt. In addition, except for the thrust plate 22, the rest of the rotor is made of non-magnetic material.

[0038] Specifically, the plurality of actuators 4 are evenly arranged along the circumference of the central axis of the rotating shaft 21 , and ensure that the same magnetic poles face the thrust plate 22 .

[0039] Specifically, refer to Figure 2As shown, the front cover 11 and / or the front end cover 13 is provided with a groove 15 capable of being engaged with the actuator 4 at an end opposite to the thrust bearing 3 .

[0040] Specifically, the two thrust bearings 3 are respectively mounted on the end faces of the front cover 11 and the front end cover 13. In addition, an adjustment gasket is provided between the thrust bearing 3 and the actuator 4. The magnitude of the magnetic attraction force can be adjusted by magnetizing the permanent magnet or changing the axial size (distance) of the bearing chamber 14 formed by the front cover 11 and the front end cover 13 and increasing or decreasing the adjustment gasket accordingly. By means of controlling the magnetic field strength of the permanent magnet, the axial force can be offset more accurately.

[0041] In one embodiment, the thrust bearing 3 is an air thrust bearing, such as a gas foil bearing.

[0042] It should be noted that, due to its working principle, the gas foil bearing not only has a theoretical upper limit of its load-bearing capacity, but also has requirements for the minimum speed when running at low speed. Therefore, when using the gas foil shaft to reduce the influence of the axial force, it is also necessary to combine simulation analysis and other means to ensure that the gas foil bearing on the non-load-bearing side at the initial speed can balance the reverse attraction of the permanent magnet on the thrust plate 22. Otherwise, excessive directional attraction will cause the air film gap to be too small or even disappear during operation, which will increase the operating risk of the air compressor shaft system.

[0043] The principle of the utility model is as follows: the magnetic acting body 4 (permanent magnet) is embedded in the axial groove 15 of the front cover 11 or the front end cover 13 opposite to the thrust plate 22 with the same magnetic pole orientation, thereby generating an attractive force in the opposite direction to the axial force caused by the pressure difference when the air compressor is running, so as to reduce the load on the thrust bearing during operation.

[0044] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to examples, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A structure for reducing the axial thrust of an air compressor during operation, characterized in that: include: The mounting body (1) comprises a front cover (11), a compression shell (12) mounted on the front cover (11), and a front end cover (13) mounted between the front cover (11) and the compression shell (12), wherein a bearing chamber (14) is formed between the front cover (11) and the front end cover (13); An impeller assembly (2) comprising a rotating shaft (21) rotatably connected to the mounting body (1), and a thrust plate (22) and an impeller (23) respectively mounted on the rotating shaft (21), wherein the impeller (23) is located between the compression shell (12) and the front end cover (13), and the thrust plate (22) is located in the bearing chamber (14); Two thrust bearings (3) are respectively installed in the bearing chamber (14) and located on both axial sides of the thrust plate (22); An acting body (4) is installed at one end of the front cover (11) or the front end cover (13) facing the thrust bearing (3), and the acting body (4) can cause the thrust plate (22) to be subjected to an axial magnetic attraction force, wherein the axial magnetic attraction force is opposite to the axial force generated when the impeller (23) rotates.

2. The structure for reducing the axial thrust of an air compressor during operation according to claim 1, characterized in that: The acting body (4) is a permanent magnet, and the thrust plate (22) is made of ferromagnetic material.

3. The structure for reducing the axial thrust of an air compressor during operation according to claim 2, characterized in that: The active body (4) includes neodymium iron boron, ferrite or samarium cobalt.

4. The structure for reducing the axial thrust of an air compressor during operation according to claim 1, characterized in that: The plurality of acting bodies (4) are evenly arranged in the circumferential direction along the central axis of the rotating shaft (21).

5. The structure for reducing the axial thrust of an air compressor during operation according to claim 1, characterized in that: The front cover (11) and / or the front end cover (13) is provided with a groove (15) capable of being fitted with the acting body (4) at an end opposite to the thrust bearing (3).

6. The structure for reducing the axial thrust of an air compressor during operation according to claim 1, characterized in that: The two thrust bearings (3) are respectively mounted on the end faces of the front cover (11) and the front end cover (13).

7. The structure for reducing the axial thrust of an air compressor during operation according to claim 1, characterized in that: An adjustment gasket is provided between the thrust bearing (3) and the acting body (4).

8. The structure for reducing the axial thrust of an air compressor during operation according to claim 1, characterized in that: The thrust bearing (3) is a gas foil bearing.

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