Air circulation machine

Abstract

The present invention provides an air cycle machine, comprising a compressor and a fan. The compressor and the fan share a rotating shaft. A bearing chamber is constructed on the fan base of the fan. A bearing is provided in the bearing chamber. The rotating shaft is supported on the bearing. A fan blade is connected to the first end of the rotating shaft. A first seal is provided on the end wall of the bearing chamber on the side close to the fan blade. The first seal is fitted onto the outer side of the rotating shaft, and a first radial sealing gap is defined between the first seal and the rotating shaft. According to the present invention, a non-contact seal is formed between the high-speed rotating shaft and the first seal, which can overcome the shortcomings of friction, wear, and friction failure caused by contact seals between fans and compressors in related technologies while ensuring airtightness between the fans and compressors.

Description

Technical Field

[0001] The invention belongs to the technical field of air conditioning, and in particular relates to an air cycle machine. Background Art

[0002] In modern aircraft environmental control systems, the air cycle machine (ACM) uses air as a medium to provide the passenger cabin with air at the desired pressure, temperature, and humidity. The ACM consists of a turbine (also known as an expander), a compressor (also known as a compressor), and a fan, all rotating around a common shaft. The compressor compresses the heat source air and transports it downstream. The compressed air expands in the turbine, converting its internal energy into mechanical energy, which drives the compressor and fan.

[0003] The ACM shaft operates at high speeds, and conventional contact seals (sealing materials are usually metal) are prone to friction, wear, and failure due to collision at high speeds. Summary of the Invention

[0004] Therefore, the present invention provides an air cycle machine that can overcome the shortcomings of friction wear and friction failure caused by contact seals between the fan and the compressor in the related art, and ensure the air tightness between the fan and the compressor.

[0005] In order to solve the above problems, the present invention provides an air cycle machine, including a compressor and a fan, the compressor and the fan share a rotating shaft, a bearing chamber is constructed on the fan base of the fan, the first end of the rotating shaft is connected to a fan blade, and a first seal is provided on the end wall of the bearing chamber on the side close to the fan blade. The first seal is mounted on the outer side of the rotating shaft, and a first radial sealing gap is defined between the first seal and the rotating shaft.

[0006] Preferably, a thrust ring is mounted on the rotating shaft, and the first sealing member has a first sealing portion surrounding the rotating shaft, and the first radial sealing gap is formed between the proximal side of the first sealing portion and the outer peripheral wall of the thrust ring.

[0007] Preferably, the first sealing portion includes a plurality of convex rings spaced apart along the axial direction of the rotating shaft, and the first radial sealing gap is formed between the top of the convex ring and the thrust ring.

[0008] Preferably, the first sealing member is an annular member, and on the axial cross-section of the first sealing member, the convex ring is a trapezoid, the upper base of the trapezoid is close to the rotating shaft, and the lower base of the trapezoid is away from the rotating shaft; and / or, a groove is formed between two adjacent convex rings, and the connection part between the groove and the convex ring is chamfered.

[0009] Preferably, the trapezoid is a right-angled trapezoid.

[0010] Preferably, the height of the right-angled trapezoid is H, the angle between the hypotenuse and the upper base is α, the length of the upper base is B, the axial spacing between two adjacent convex rings is D, and the radial width of the first radial sealing gap is δ.

[0011] Preferably, 0.8 mm ≤ H ≤ 2 mm, 10° < α ≤ 20°, 0.2 mm ≤ B ≤ 0.5 mm, and 0.6 mm ≤ D ≤ 2 mm.

[0012] Preferably, H=1.1mm, α=18°, B=0.3mm, D=1.3mm.

[0013] Preferably, a first ring platform and a second ring platform are provided on the side of the fan base facing the fan blade. The first ring platform and the second ring platform are coaxially arranged with the bearing chamber, and the inner diameters of the bearing chamber, the second ring platform and the first ring platform increase successively. The first seal is connected to the first ring platform, and the bearing is connected to the second ring platform.

[0014] Preferably, a second sealing member is provided on the end wall of the bearing chamber away from the fan blade, the second sealing member is sleeved on the outer side of the rotating shaft, and a second radial sealing gap is defined between the second sealing member and the rotating shaft.

[0015] Preferably, a sleeve is further mounted on the rotating shaft, and the second sealing member has a second sealing portion surrounding the rotating shaft, and the second radial sealing gap is formed between the proximal side of the second sealing portion and the outer peripheral wall of the sleeve.

[0016] The air circulation machine provided by the present invention has a non-contact sealing structure between the high-speed rotating shaft and the first sealing member through the setting of the first radial sealing gap. This can overcome the shortcomings of friction wear and friction failure caused by contact sealing between the fan and the compressor in related technologies while ensuring the air tightness between the fan and the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of an air cycle machine according to an embodiment of the present invention (some irrelevant components are omitted);

[0018] Figure 2 for Figure 1 A partial enlarged view of point A in the middle;

[0019] Figure 3 for Figure 1 Schematic diagram of the structure of the fan base;

[0020] Figure 4 for Figure 1 A partial enlarged schematic diagram of the middle seal.

[0021] The reference numerals indicate:

[0022] 1. Compressor; 2. Fan; 21. Fan base; 211. Bearing chamber; 212. First ring platform; 213. Second ring platform; 214. Third ring platform; 3. First seal; 31. First sealing portion; 32. Protruding ring; 33. Groove; 4. Second seal; 100. Rotating shaft; 101. Bearing; 102. Fan blade; 103. Thrust ring; 104. Sleeve. DETAILED DESCRIPTION

[0023] See also Figures 1 to 4 As shown, according to an embodiment of the present invention, an air cycle machine is provided, comprising a compressor 1 and a fan 2. The compressor 1 and the fan 2 share a rotating shaft 100. A bearing chamber 211 is constructed on a fan base 21 of the fan 2. The bearing chamber 211 is provided with a bearing 101. The bearing 101 can specifically be a dynamic pressure radial bearing. The rotating shaft 100 is supported on the bearing 101. A fan blade 102 is connected to a first end of the rotating shaft 100. A first seal 3 is provided on the end wall of the bearing chamber 211 on the side near the fan blade 102. The first seal 3 is mounted on the outer side of the rotating shaft 100, and a first radial sealing gap is formed between the first seal 3 and the rotating shaft 100. In this technical solution, the provision of the first radial sealing gap provides a non-contact sealing structure between the high-speed rotating shaft 100 and the first seal 3. This can overcome the shortcomings of the contact seal between the fan and the compressor in the related art, such as friction wear and friction failure, while ensuring the airtightness between the fan 2 and the compressor 1. In addition, it should be noted that, in this technical solution, the bearing chamber 211 is directly constructed on the fan base 21, which can make the structure of the air cycle machine more compact.

[0024] In some embodiments, a thrust ring 103 is mounted on the rotating shaft 100. The first seal 3 includes a first sealing portion 31 surrounding the rotating shaft 100. A first radial sealing gap is formed between the proximal side of the first sealing portion 31 and the outer peripheral wall of the thrust ring 103. The thrust ring 103 can, on the one hand, limit the axial displacement of the rotating shaft 100 and prevent axial movement, and on the other hand, adjust and match the sealing gap formed with the first sealing portion 31 to further ensure airtightness between the fan 2 and the compressor 1. The seal 3 can be made of a carbon alloy material (e.g., forged blank 6A02).

[0025] In some embodiments, the first sealing portion 31 includes multiple raised rings 32 spaced axially along the rotating shaft 100. The tops of the raised rings 32 form the first radial sealing gap with the thrust ring 103. The multiple raised rings 32 spaced axially along the rotating shaft 100 can multiple times reduce the airflow in the pressure source, thereby achieving a labyrinth seal. A groove 33 is formed between two adjacent raised rings 32. The connection between the groove 33 and the raised ring 32 is rounded to prevent stress concentration at the intersection of the groove 33 and the raised ring 32 and facilitate machining. For example, the radius of the rounding is R, with 0.1mm≤R≤0.5mm.

[0026] As the pressure differential increases, the leakage of the labyrinth seal also increases. The triangular shape has the highest leakage, while the rectangular shape has less leakage. Improving the rectangular seal to a trapezoidal structure can increase the complexity of the fluid flow path, increase the fluid flow resistance, and further improve the sealing effect. Specifically, the seal 3 is an annular member. In the axial cross-section of the seal 3, the raised ring 32 is a trapezoid, with the upper base of the trapezoid close to the rotating shaft 100 and the lower base away from the rotating shaft 100. Preferably, the trapezoid is a right-angled trapezoid. Furthermore, the height of the right-angled trapezoid is H, the angle between the hypotenuse and the upper base is α, the length of the upper base is B, the axial spacing between two adjacent protruding rings 32 is D, and the radial width of the first radial sealing gap is δ. It should be noted that in this formula, H, B, and D are the values corresponding to the corresponding physical quantities in mm, and α is the value corresponding to the corresponding physical quantity in degrees. After the design of H, B, D, and α is determined, their respective dimension units are unified into mm or degrees, and then the corresponding specific values are substituted into the above formula. In order to make the radial width of the first radial sealing gap adapt to the pressure difference between the pressure fluids in the compressor 1 and the fan 2, thereby ensuring a more reasonable gap design and better airtightness, preferably, 0.8mm≤H≤2mm, 10°<α≤20°, 0.2mm≤B≤0.5mm, and 0.6mm≤D≤2mm. Furthermore, H = 1.1mm, α = 18°, B = 0.3mm, D = 1.3mm, and the corresponding δ is about 0.2mm.

[0027] In some embodiments, a first ring platform 212 and a second ring platform 213 are provided on the side of the fan base 21 facing the fan blade 102. The first ring platform 212 and the second ring platform 213 are coaxially arranged with the bearing chamber 211, and the inner diameters of the bearing chamber 211, the second ring platform 213 and the first ring platform 212 increase successively. The first seal 3 is detachably connected (for example, by corresponding bolts) to the first ring platform 212, and the bearing 101 is detachably connected (for example, by corresponding bolts) to the second ring platform 213.

[0028] In some embodiments, a second seal 4 is provided on the end wall of the bearing chamber 211 on the side away from the fan blade 102. The second seal 4 is mounted on the outer side of the rotating shaft 100, and a second radial sealing gap is formed between the second seal 4 and the rotating shaft 100. That is, in this technical solution, the axial ends of the bearing chamber 211 are double-sealed by the first seal 3 and the second seal 4, respectively, thereby effectively preventing the pressurized fluid in the fan 2 and the compressor 1 from flowing. It is worth mentioning that the use of the first seal 3 and the second seal 4 to jointly form a seal between the fan 2 and the compressor 1 can make the sealing interval longer and the sealing effect better.

[0029] In some embodiments, a sleeve 104 is further fitted (e.g., by interference fit) onto the rotating shaft 100. The sleeve 104 preferably also has a corresponding flanged thrust portion, located on the side of the bearing chamber 211 away from the fan blades 102. Together with the thrust ring 103, this portion provides a bidirectional axial limit for the rotating shaft 100. Similar to the structure of the first seal 3, the second seal 4 includes a second sealing portion surrounding the rotating shaft 100. A second radial sealing gap is defined between the proximal side of the second sealing portion and the outer peripheral wall of the sleeve 104. This second radial sealing gap can be the same as the first radial sealing gap. In terms of specific structural design, the second seal 4 and the first seal 33 can also be designed identically. A third annular platform 214 is constructed on the end wall of the bearing chamber 211 away from the fan blades 102. The second seal 4 is detachably connected to the third annular platform 214.

[0030] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0031] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art may make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. An air cycle machine, comprising a compressor (1) and a fan (2), wherein the compressor (1) and the fan (2) share a rotating shaft (100), characterized in that: A bearing chamber (211) is constructed on the fan base (21) of the fan (2), a fan blade (102) is connected to the first end of the rotating shaft (100), a first sealing member (3) is provided on the end wall of the bearing chamber (211) on the side close to the fan blade (102), the first sealing member (3) is sleeved on the outer side of the rotating shaft (100), and a first radial sealing gap is formed between the first sealing member (3) and the rotating shaft (100); the first sealing member (3) has a first sealing portion (31) surrounding the rotating shaft (100), and the first sealing portion ( 31) includes a plurality of convex rings (32) arranged at intervals along the axial direction of the rotating shaft (100); the first sealing member (3) is an annular member, and on the axial cross section of the first sealing member (3), the convex ring (32) is a trapezoid, the upper base of the trapezoid is close to the rotating shaft (100), and the lower base of the trapezoid is away from the rotating shaft (100); the trapezoid is a right-angled trapezoid; the height of the right-angled trapezoid is H, the angle between the hypotenuse and the upper base is α, the length of the upper base is B, the axial spacing between two adjacent convex rings (32) is D, the radial width of the first radial sealing gap is δ, 2. The air cycle machine according to claim 1, wherein: A thrust ring (103) is sleeved on the rotating shaft (100), and the first radial sealing gap is formed between the proximal axial side of the first sealing portion (31) and the outer peripheral wall of the thrust ring (103).

3. The air cycle machine according to claim 2, wherein: The first radial sealing gap is formed between the top of the convex ring (32) and the thrust ring (103).

4. The air cycle machine according to claim 3, wherein: A groove (33) is formed between two adjacent convex rings (32), and a connection portion between the groove (33) and the convex ring (32) is rounded.

5. The air cycle machine according to claim 1, wherein: 0.8mm≤H≤2mm, 10°<α≤20°, 0.2mm≤B≤0.5mm, 0.6mm≤D≤2mm.

6. The air cycle machine according to claim 5, wherein: H=1.1mm, α=18°, B=0.3mm, D=1.3mm.

7. The air cycle machine according to claim 1, wherein: A first ring platform (212) and a second ring platform (213) are provided on a side of the fan base (21) facing the fan blade (102); the first ring platform (212) and the second ring platform (213) are coaxially arranged with the bearing chamber (211); and the inner diameters of the bearing chamber (211), the second ring platform (213) and the first ring platform (212) increase in sequence; the first sealing member (3) is connected to the first ring platform (212), and the bearing (101) is connected to the second ring platform (213).

8. The air cycle machine according to claim 7, wherein: A second sealing member (4) is provided on the end wall of the bearing chamber (211) on the side away from the fan blade (102). The second sealing member (4) is sleeved on the outer side of the rotating shaft (100), and a second radial sealing gap is provided between the second sealing member (4) and the rotating shaft (100).

9. The air cycle machine according to claim 8, wherein: The rotating shaft (100) is also provided with a sleeve (104), and the second sealing member (4) has a second sealing portion surrounding the rotating shaft (100), and a second radial sealing gap is formed between the proximal side of the second sealing portion and the outer peripheral wall of the sleeve (104).

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