A sealing and connecting structure between impellers

Abstract

The present invention belongs to the field of auxiliary power units, and particularly relates to a sealing and connecting structure for between impellers, including an end tooth ring, a centrifugal impeller, and a centripetal impeller. The end tooth ring is used for centering with the centrifugal impeller and transmitting torque. By setting a sealing labyrinth structure and an arc end tooth structure, a sealing structure is formed in cooperation with the honeycomb. The large chamber between the compressor and the turbine is divided into two small chambers by a partition. A small clearance fit is adopted radially between the partition and the compressor rotor and the turbine rotor. The honeycomb is welded to the inner cylindrical surface of the partition ring to reduce the cold air flow and improve the APU efficiency. The end tooth ring of the present invention adopts a detachable connection method between the end face and the cylindrical surface. If the labyrinth teeth are worn, the end tooth ring can be replaced, improving the maintainability of the structure.

Description

Technical Field

[0001] The present invention belongs to the field of auxiliary power units, and particularly relates to a sealing and connecting structure between impellers. Background Art

[0002] An auxiliary power unit refers to a small auxiliary power unit that can independently output compressed air or supply power outside the main power unit (engine) on an aircraft. Generally, it is a small gas turbine engine. It includes a power output shaft, a compressed air extraction device, an automatic control device, etc. Before takeoff, it provides compressed air for the aircraft, which can be used for the air conditioning system of the aircraft or as a gas source for starting the main engine starter, and can also output power to the aircraft's electrical system before the main engine starts, reducing the aircraft's dependence on airport equipment; during flight, when the main engine or its power generation device fails, it can provide emergency energy for the aircraft, improving flight safety; when landing, it can also provide energy for the aircraft. Auxiliary power units are installed on large and medium-sized aircraft and large helicopters.

[0003] In the existing auxiliary power unit, a partition is used between the centrifugal compressor and the radial turbine to divide the large chamber between the compressor and the turbine into two small chambers. The rotors of the centrifugal compressor and the radial turbine generally use cylindrical surfaces for centering, transmit torque through friction between the cylindrical surface and the end face and pins, or use arc end teeth for centering and torque transmission. In order to prevent rubbing between the rotating and stationary parts, a large clearance fit is used radially between the partition and the compressor rotor and the turbine rotor, without a sealing effect. Under the conditions of the same flow rate and other parameters, it will reduce the efficiency of the auxiliary power unit (hereinafter referred to as APU).

[0004] In order to solve the problems of positioning, torque transmission, and sealing of the centrifugal impeller of the APU compressor and the radial impeller of the turbine, it is necessary to design an integrated structure of arc end teeth and sealing labyrinth teeth, reduce the number of parts, and through the integrated structure of arc end teeth and sealing labyrinth teeth and a small clearance fit with the honeycomb, reduce the cold air flow rate towards the turbine end, improve the efficiency of the auxiliary power unit, and improve the reliability and maintainability of the auxiliary power unit. Summary of the Invention

[0005] In order to overcome the defects existing in the above-mentioned prior art, the purpose of the present invention is to provide a sealing and connecting structure between impellers. Through the integrated design of arc end teeth and sealing labyrinth teeth, the number of parts is reduced. At the same time, through the integrated structure of arc end teeth and sealing labyrinth teeth and a small clearance fit with the honeycomb, the cold air flow rate towards the turbine end is reduced, the efficiency of the auxiliary power unit is improved, and the reliability and maintainability of the auxiliary power unit in use are improved.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A sealing and connecting structure between impellers, comprising an end tooth ring, a centrifugal impeller and a centripetal impeller. The end tooth ring is used for centering with the centrifugal impeller and transmitting torque.

[0008] Further, one side of the end tooth ring is provided with arc end teeth.

[0009] Further, the centrifugal impeller is provided with grooves, and the grooves correspond to and engage with the arc end teeth one by one.

[0010] Further, the inner ring of the end tooth ring is a smooth curved surface, and a ring-shaped limiting block is arranged at the corresponding position of the centripetal impeller to the inner ring of the end tooth ring. The inner ring of the end tooth ring is in contact with the outer circumferential surface of the ring-shaped limiting block.

[0011] Further, the other side of the end tooth ring is an end face, and the end face is detachably connected to the centripetal impeller.

[0012] Further, sealing labyrinth teeth are arranged on the circumferential surface of the end tooth ring.

[0013] Further, an annular partition is arranged outside the sealing labyrinth teeth.

[0014] Further, a honeycomb is fixedly connected to the inner cylindrical surface of the partition.

[0015] Further, a gap is left between the honeycomb and the sealing labyrinth teeth, and the gap does not exceed 0.3 mm.

[0016] Further, the gap and the spaces on both sides of the partition form a flow path.

[0017] The technical effects and advantages of the present invention:

[0018] 1. By setting the sealing labyrinth tooth structure and the arc end tooth structure, a sealing structure is formed in cooperation with the honeycomb. The large chamber between the compressor and the turbine is divided into two small chambers by the partition. The partition is in a small clearance fit with the compressor rotor and the turbine rotor in the radial direction. The honeycomb is welded to the inner cylindrical surface of the partition to reduce the cold air flow rate and improve the APU efficiency.

[0019] 2. The structure of the present invention allows slight abrasion between the sealing labyrinth teeth and the honeycomb, greatly improving the reliability of the structure.

[0020] 3. The end tooth ring of the present invention adopts a detachable connection method between the end face and the cylindrical surface. If the labyrinth teeth are worn, the end tooth ring can be replaced, improving the maintainability of the structure.

[0021] 4. The arc end tooth structure and the sealing labyrinth tooth structure of the present invention are integrally designed, reducing the number of parts and optimizing the device structure.

[0022] Other features and advantages of the present invention will be set forth in the following description, and in part will be obvious from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention may be realized and attained by the structure pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a sealing and connecting structure between impellers of the present invention;

[0024] Figure 2 is a schematic structural diagram of the end tooth ring of the present invention.

[0025] Reference numerals: 1, arc end teeth; 2, sealing labyrinth teeth; 3, end face; 4, end tooth ring; 5, centrifugal impeller; 6, honeycomb; 7, flow path; 8, centripetal impeller; 9, partition; 10, inner ring; 11, annular limit block. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Figure 1 is a schematic structural diagram of a sealing and connecting structure between impellers of the present invention. As Figure 1 shown, the present invention provides a sealing and connecting structure between impellers, including an end tooth ring 4, a centrifugal impeller 5 and a centripetal impeller 8. The end tooth ring 4 is used for centering with the centrifugal impeller 5 and transmitting torque.

[0028] Further, an arc end tooth 1 is provided on one side of the end tooth ring 4. The centrifugal impeller 5 is provided with a groove, and the groove corresponds to and meshes with the arc end tooth 1 one by one. For example, the arc end tooth 1 is designed as a convex platform with a narrow upper part and a wide lower part, and the groove is set as a tooth groove with a wide upper part and a narrow lower part corresponding to and matching the arc end tooth 1 in size to ensure the stability of the transmission between the end tooth ring 4 and the centrifugal impeller 5. The other side of the end tooth ring 4 is an end face 3, and the end face 3 is in contact with the centripetal impeller 8. The end face 3 and the centripetal impeller 8 are detachably connected. For example, two cylindrical holes are symmetrically arranged on the end face 3, positioning pins are arranged at the corresponding connection positions of the centripetal impeller 8, and the end face 3 is detachably connected to the centripetal impeller 8 through the cylindrical holes and the positioning pins.

[0029] Further, Figure 2 is a schematic structural diagram of the end tooth ring 4 of the present invention. As Figure 2As shown in the figure, the outer circumferential surface of the end tooth ring 4 is provided with a sealing labyrinth 2. An annular partition 9 is arranged outside the sealing labyrinth 2. A honeycomb 6 is fixedly connected to the inner cylindrical surface of the inner ring of the partition 9. A gap is left between the honeycomb 6 and the sealing labyrinth 2, and the gap does not exceed 0.3 mm. The gap and the spaces on both sides of the partition 9 form a flow path 7. The inner ring 10 of the end tooth ring 4 is a smooth curved surface. A ring-shaped limiting block 11 is arranged at the position corresponding to the inner ring 10 of the end tooth ring 4 on the centripetal impeller 8. The inner ring 10 of the end tooth ring 4 is in contact with the outer circumferential surface of the ring-shaped limiting block 11, playing a role in limiting and fixing the end tooth ring 4.

[0030] The working principle of the present invention is as follows. The large chamber between the compressor and the turbine is divided into two small chambers by the partition 9. The partition 9 is in a small clearance fit with the compressor rotor and the turbine rotor in the radial direction. The honeycomb 6 is welded to the inner cylindrical surface of the inner ring of the partition 9. The gap between the honeycomb 6 and the sealing labyrinth 2 is controlled within 0.3 mm. When the air flow passes through the structure of the sealing labyrinth 2 and the honeycomb 6 from the centrifugal impeller 5 end and flows towards the centripetal impeller 8 end, the air flow passes through the flow path 7, and the air flow velocity decreases. At the same time, the radial clearance at the sealing part can be reduced to 0.3 mm, and the air flow rate decreases. Under the conditions of parameters such as the APU inlet flow rate, the APU efficiency can be improved. At the same time, this structure allows the sealing labyrinth 2 and the honeycomb 6 to be slightly abraded, improving the reliability of the structure. If the abrasion is serious, the end tooth ring 4 with a lower cost can be replaced, and there is no need to replace the centripetal impeller 8 with a higher cost, improving the maintainability of the structure. On the other hand, the structure of the sealing labyrinth 2 and the arc end tooth 1 is integrally designed, reducing the number of parts, simplifying the structure, and facilitating the overall disassembly and installation.

[0031] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A sealing and connecting structure between impellers, characterized in that, It includes a spline ring (4), a centrifugal impeller (5) and a centripetal impeller (8). The spline ring (4) is used for centering with the centrifugal impeller (5) and transmitting torque; One side of the spline ring (4) is provided with arc splines (1); The centrifugal impeller (5) is provided with grooves, and the grooves correspond to and engage with the arc splines (1) one by one; The inner ring (10) of the spline ring (4) is a smooth surface, and a ring-shaped limiting block (11) is provided at the position of the centripetal impeller (8) corresponding to the inner ring (10) of the spline ring (4). The inner ring (10) of the spline ring (4) is attached to the outer circumferential surface of the ring-shaped limiting block (11); The other side of the spline ring (4) is an end face (3), and the end face (3) is detachably connected to the centripetal impeller (8); The circumferential surface of the spline ring (4) is provided with sealing labyrinth teeth (2); An annular partition plate (9) is arranged outside the sealing labyrinth teeth (2).

2. The sealing and connecting structure for between impellers according to claim 1, wherein, A honeycomb (6) is fixedly connected to the inner cylindrical surface of the partition plate (9).

3. A sealing and connecting structure for between impellers according to claim 2, characterized in that, A gap is left between the honeycomb (6) and the sealing labyrinth teeth (2), and the gap does not exceed 0.3 mm.

4. A sealing and connecting structure for between impellers according to claim 3, characterized in that, The gap and the spaces on both sides of the partition plate (9) form a flow path (7).

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