Aero-engine, shaft and over-rotation protection device for shaft fracture

Abstract

The invention provides an aero-engine, a shaft and an over-rotation protection device for shaft breakage, the over-rotation protection device comprises a retaining sleeve shaft connected with the shaft, and the first end and the second end of the retaining sleeve shaft are arranged on the upstream and the downstream of an easy-to-break position respectively so as to serve as an alternative shaft structure after the easy-to-break position is broken. According to the over-rotation protection device, the hollow maintaining sleeve shaft serves as a replacement shaft structure at the shaft fracture position in time, the maintaining sleeve shaft not only provides the function of continuously transmitting torque, but also can meet the requirements of airflow or liquid flow sealing and the like of the axis, effective remedy is conducted after the shaft is fractured, and the over-rotation fault is prevented; the sleeve shaft is simple in structure, high in efficiency and practical, and the sleeve shaft can be arranged at a possible position easy to break without excessively increasing the weight.

Description

Technical Field

[0001] This invention relates to the field of aero-engines, and more specifically to the field of overspeed protection devices. Background Technology

[0002] An aero engine consists of components arranged sequentially along the airflow direction, including the air intake, fan, compressor, combustion chamber, turbine, and exhaust nozzle. Among these, the compressor, combustion chamber, and turbine form the core engine.

[0003] The intake duct and fan direct airflow into the compressor. The compressor, consisting of a low-pressure compressor and a high-pressure compressor, compresses air stage by stage using multi-stage rotating blades, increasing the air pressure and temperature to provide a high-energy working medium for subsequent combustion. The high-pressure air mixes with injected fuel in the combustion chamber and burns stably, releasing a large amount of heat energy, causing a rapid increase in air temperature and volume, forming a high-energy airflow. As the high-temperature, high-pressure gas passes through the turbine, it drives the turbine blades to rotate. The turbine extracts energy from the gas and drives the compressor and fan ahead via a coaxial connection. The remaining gas expands through the exhaust nozzle and is ejected at high speed, generating thrust.

[0004] Engine shafts are crucial components of aircraft engines. They are the force-transmitting devices connecting various rotor assemblies, such as the fan, compressor, and turbine, and also provide positioning and support through their interaction with bearings and the engine casing. Therefore, shaft breakage can easily lead to very serious consequences, and in some cases, even non-containment failures.

[0005] For example, the low-pressure turbine shaft of a twin-rotor turbofan engine is a crucial component connecting the low-pressure turbine to the low-pressure compression components. In a typical engine, the low-pressure turbine shaft must pass through the entire core section, making it the longest main shaft of the engine. Its characteristics include being hollow, slender, rotating at high speeds, and transmitting large torques. Due to the small clearance between the low-pressure turbine shaft and other components, it is prone to fracture not only due to its inherent structural characteristics but also due to secondary damage caused by the failure of other components. Therefore, it is highly susceptible to fracture failure.

[0006] How to prevent accidents caused by shaft breakage is an urgent problem to be solved.

[0007] For example, patent application GB843479A discloses an improved solution for the problem of drive shaft fracture. If the shaft driving the propeller fails, or in a twin-shaft engine, if the shaft driving the compressor and propeller fails, the turbine will accelerate rapidly due to the loss of drive load. If left unchecked, this can lead to overspeeding and serious damage, such as turbine rotor bursting, resulting in non-containment failure. The solution involves a pair of mechanically interconnected components at both ends of the drive shaft, mechanically connected to the rotor assemblies at each end. When the drive shaft fails and the turbine and driven components rotate relative to each other, one of these components moves relative to the adjacent end of the drive shaft. This movement reduces the engine's fuel supply, effectively cutting off the fuel supply. The mechanically interconnected component includes a rod and a sleeve. One end of the rod is fixed to the turbine rotor, and the other end is connected to the sleeve via a threaded structure. The sleeve is supported in a bushing, thus allowing axial displacement of the sleeve. If the shaft breaks during engine operation, the rod rotates relative to the sleeve, causing the sleeve to displace axially relative to the compressor rotor. This closes the shut-off valve, quickly cutting off the engine's fuel supply and preventing serious damage from overspeeding. This method uses a mechanically interconnected component to trigger the fuel shut-off mechanism by providing axial displacement, thus achieving rapid protection against turbocharger overspeed and preventing catastrophic damage by cutting off fuel supply.

[0008] For example, patent application CN114165339A discloses a speed limiting device and method for a turbine engine. Based on a ventilation duct structure located within the low-pressure shaft, the ventilation duct is connected to the low-pressure shaft and the low-pressure turbine support cone wall using torque-transmitting connection structures, such as rigid or floating connections. In the event of shaft failure, the low-pressure turbine rotor continues to couple with the booster rotor and fan, transmitting torque through the ventilation duct, thus buying time for the control system to issue a fuel cut-off command. However, this structure is suitable only for engines with appropriate ventilation duct structures.

[0009] A general overspeed protection function must be provided for this type of shaft failure to prevent serious consequences. Summary of the Invention

[0010] One object of the present invention is to provide an over-rotation protection device for shaft breakage, which can effectively improve the safety of the rotating shaft.

[0011] Another object of the present invention is to provide a shaft including the over-rotation protection device.

[0012] Another object of the present invention is to provide an aircraft engine.

[0013] The shaft includes at least one easily broken position. To achieve the above purpose, an over-rotation protection device is installed on the shaft, including a retaining sleeve shaft connected to the shaft. The first end and the second end of the retaining sleeve shaft are respectively located upstream and downstream of the easily broken position, so as to serve as a replacement shaft structure after the easily broken position breaks.

[0014] In one or more embodiments, the retaining sleeve is disposed inside the shaft.

[0015] In one or more embodiments, the retaining sleeve is connected to the inner wall of the shaft via a toothed connection.

[0016] In one or more embodiments, the over-rotation protection device further includes a limiting portion disposed on the inner wall of the shaft for limiting the retaining sleeve shaft.

[0017] In one or more embodiments, the limiting portion includes a stepped structure and / or a retaining ring structure.

[0018] In one or more embodiments, the retaining sleeve is fitted over the outside of the shaft.

[0019] In one or more embodiments, the retaining sleeve is fixedly connected to the shaft.

[0020] In one or more embodiments, the retaining sleeve is welded to the shaft or connected by fasteners.

[0021] In one or more embodiments, the retaining sleeve shaft is provided with an energy storage pre-torsion unit for providing a torque in the opposite direction to the torque generated by the shaft after the shaft breaks.

[0022] In one or more embodiments, the energy storage pre-torsion unit includes an elastic energy storage element.

[0023] In one or more embodiments, the elastic energy storage element includes a torsion spring or a torsion bar.

[0024] In one or more embodiments, the retaining sleeve shaft includes a retaining sleeve and an energy storage pre-torsion unit. The retaining sleeve is a cantilever structure and includes a fixed end and a free end. At least a portion of the energy storage pre-torsion unit is located inside the retaining sleeve, so that the retaining sleeve and the energy storage pre-torsion unit form a double-layer structure. The energy storage pre-torsion unit provides a second end of the retaining sleeve shaft, and the free end is not connected to the second end.

[0025] In one or more embodiments, the free end includes a sleeve connecting tooth for connecting with the inner wall sleeve tooth of the shaft, and the second end includes an energy storage connecting tooth for connecting with the inner wall sleeve tooth of the shaft.

[0026] In one or more embodiments, the shaft includes multiple fracture-prone locations, each of which is provided with a retaining sleeve shaft.

[0027] The aforementioned over-rotation protection device uses a hollow retaining sleeve shaft as a replacement shaft structure at the point of shaft breakage. The retaining sleeve shaft not only provides the function of continuing to transmit torque, but also retains the airflow or liquid flow sealing requirements of the shaft core, effectively remedying the situation after shaft breakage and preventing over-rotation failure. Furthermore, the sleeve shaft structure is simple and efficient, and placing it at a potentially breakable location does not excessively increase the weight, making it quite practical. Attached Figure Description

[0028] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the protective bushing located inside the shaft; Figure 2 This is a schematic diagram of the protective bushing after the shaft breaks; Figure 3 This is an external schematic diagram of a specific embodiment of the protective bushing; Figure 4 This is a cross-sectional view of a specific embodiment of the protective bushing.

[0029] Symbol marking explanation

[0030] 5. Shaft; 50. Inner wall; 51. Limiting part; 52. Front shaft; 53. Rear shaft; 55. Inner wall sleeve teeth; 100. Retaining sleeve shaft; 101. First end; 102. Second end; 103. Outer sleeve teeth; 105. Outer retaining sleeve; 110. Energy storage pre-torsion unit; 113. Sleeve connecting sleeve teeth; 114. Energy storage connecting sleeve teeth; 1051. Fixed end; 1052. Free end. Detailed Implementation

[0031] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0032] It should be noted that these and other accompanying drawings are merely examples and are not drawn to scale, and should not be construed as limiting the scope of protection of the present invention.

[0033] This invention provides a novel protection device for shaft fracture. When a fracture occurs at a dangerous location, the retaining shaft can continue to transmit torque for a short period of time, thus preventing the decoupling of the low-pressure turbine and the low-pressure compression components and the overrunning of the low-pressure turbine rotor.

[0034] Reference Figure 1 and Figure 2 Understood, the over-rotation protection device includes a retaining sleeve 100, which is connected to the shaft 5. The first end 101 and the second end 102 of the retaining sleeve 100 are respectively located upstream and downstream of the fracture-prone position A, so as to serve as a replacement shaft structure after the fracture at the fracture-prone position. This not only provides the function of continuing to transmit torque, but also preserves the airflow or liquid flow sealing requirements of the shaft.

[0035] This retaining sleeve structure requires no additional adjustment and can immediately serve as a replacement shaft structure to bear the load in the event of shaft failure, providing timely remedial protection without the need for additional adjustment or adaptation.

[0036] The retaining sleeve 100 can be located inside or outside the shaft 5. For the retaining sleeve located inside the shaft, a gear connection scheme can be used, which features small size and high torque transmission efficiency.

[0037] For the retaining sleeve shaft 100 located externally, bolts, welding or other connection methods can be used to fix the retaining sleeve shaft to the shaft. The retaining sleeve shaft provides reliable torque transmission function in a short time, avoiding over-rotation failure caused by the complete breakage of the low-pressure turbine shaft.

[0038] Specifically, such as Figure 1 and Figure 2 As shown, the retaining sleeve shaft 100 located inside shaft 5 adopts a boltless connection scheme, and the retaining sleeve shaft 100 and the inner wall of shaft 5 are connected by a toothed connection.

[0039] Only the first end 101 and the second end 102 of the retaining sleeve 100 are connected to the inner wall of the shaft 5 by a toothed connection. The remaining positions are not directly in contact with the shaft 5, but form a gap to allow the shaft 5 to rotate normally.

[0040] Figure 3 The structure of the retaining sleeve 100 is shown, including external sleeve teeth 103 at both ends, which engage with internal sleeve teeth 55 on the inner wall of the shaft 5.

[0041] In some embodiments, a limiting part 51 is also provided on the inner wall 50 of the shaft 5 to limit the retaining sleeve shaft 100.

[0042] The limiting part 51 includes, but is not limited to, a stepped structure or a retaining ring structure. For example, one end of the retaining sleeve 100 is limited by a stepped structure, and the other end is limited by a retaining ring.

[0043] In addition, the retaining sleeve shaft is also provided with an energy storage pre-torsion unit 110, which is used to provide a torque in the opposite direction to the torque generated by the shaft after the shaft breaks.

[0044] The energy storage pre-torsion unit 110 includes, but is not limited to, an elastic energy storage component.

[0045] In some embodiments, the energy storage pre-torsion unit 110 includes a torsion spring or a torsion bar. One end of the torsion bar or torsion spring is fixed, and the other end undergoes elastic torsion when torsion is applied, forming a certain "torsional energy storage", and this energy is in the opposite direction to the torque generated when the shaft breaks.

[0046] exist Figure 2 In the embodiment shown, after the shaft 5 breaks, it is divided into a front shaft 52 and a rear shaft 53. After the shaft breaks, the front shaft 52 has a rotation direction B. The energy storage pre-torsion unit 110 can release torque along the rotation direction C. The rotation direction C is opposite to the rotation direction B. After the shaft breaks, the energy storage pre-torsion unit gives the rear shaft 53 a certain reverse torque in advance to reduce the rotation speed in advance. In some cases, it can also make the rear shaft 53 rotate at a low speed in the rotation direction C.

[0047] In other embodiments, after the shaft 5 breaks, it is divided into a front shaft 52 and a rear shaft 53. After the shaft breaks, the front shaft 52 has a rotation direction B. The energy storage pre-torsion unit 110 can also release torque along the rotation direction C to the front shaft 52. The rotation direction C is opposite to the rotation direction B, providing a torque reduction for the front shaft 52.

[0048] In this way, when the low-pressure turbine shaft of the turbofan engine breaks at a dangerous position, the internal retaining sleeve shaft can provide the function of continuing to transmit torque for a short time. At the same time, the energy storage pre-torsion unit 110 can quickly offset the rotation caused by the breakage, preventing the low-pressure turbine from decoupling from the low-pressure compression components and causing the low-pressure turbine rotor to run wildly, thereby avoiding non-containment hazards.

[0049] The above structure maintains a certain pre-torsion function for the bushing shaft, providing a reverse torque when the shaft breaks. This effectively reduces the speed of the turbine rotor by applying external force, providing a certain anti-rotation effect.

[0050] Figure 3 and Figure 4 A specific embodiment of the energy storage pre-torsion unit 110 is shown. The retaining sleeve 100 has a double-layer structure, including an outer retaining sleeve 105 located on the outside and an energy storage pre-torsion unit 110 located on the inside.

[0051] The external retaining sleeve 105 has a cantilever structure, such as Figure 4As shown, it includes a fixed end 1051 and a free end 1052. The fixed end 1051 on the left provides an external sleeve tooth 103, and the free end 1052 on the right provides a sleeve connecting sleeve tooth 113. The free end 1052 is not connected to the second end 102 of the retaining sleeve shaft; that is, there is a gap between the free end 1052 and the second end, as shown. Figure 4 As shown.

[0052] The energy storage pre-torsion unit 110 has an energy storage connecting sleeve tooth 114 at one end on the right side, which serves as the second end of the retaining sleeve shaft. Specifically, the energy storage connecting sleeve tooth 114 provides the function of an external sleeve tooth at the second end. Since the external retaining sleeve 105 has a cantilever structure, the sleeve connecting sleeve tooth 113 and the energy storage connecting sleeve tooth 114 located on the free end 1052 are independent structures.

[0053] Figure 4 In the middle, the sleeve connecting sleeve 113 and the energy storage connecting sleeve 114 on the right side and the outer sleeve 103 on the left side all mate with the inner wall sleeve 55 on the inner wall of the shaft 5.

[0054] When the shaft breaks, the shaft 5 is divided into the front shaft 52 and the rear shaft 53. After the sleeve connecting tooth 113 of the retaining sleeve shaft 100 disengages from the inner wall sleeve tooth 55 on the inner wall of the shaft, the energy storage pre-torsion unit 110 is triggered to release, providing reverse torque and effectively reducing the rotation speed.

[0055] The energy storage pre-torsion unit 110 may include a sleeve body and a torsion spring or torsion bar circumferentially distributed on the outer side of the sleeve body. An energy storage connecting tooth 114 is provided at the right end of the sleeve body. One end of the torsion spring or torsion bar is fixed, while the other end is under torsion under the influence of a cantilevered outer retaining sleeve 105, generating elastic torsion and storing torsional energy. When the sleeve connecting tooth 113 of the outer retaining sleeve 105 disengages from the inner wall tooth 55 on the inner wall of the shaft, the torsion end of the torsion spring or torsion bar is released, thereby releasing the torsional energy to the front axle and / or rear axle, achieving the effect of reducing rotational speed.

[0056] It is also understandable that if the shaft has multiple locations prone to breakage, the aforementioned retaining sleeve shaft structure can be installed at each of these locations.

[0057] Based on the above description of the protective bushing, we can also understand a shaft structure with the bushing and an aircraft engine.

[0058] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0059] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0060] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. An over-rotation protection device for shaft breakage, mounted on a shaft, said shaft including at least one easily breakable position, characterized in that, The over-rotation protection device includes a retaining sleeve shaft connected to the shaft. The first end and the second end of the retaining sleeve shaft are respectively located upstream and downstream of the easily broken position, so as to serve as a replacement shaft structure after the easily broken position breaks.

2. The overspeed protection device as described in claim 1, characterized in that, The retaining sleeve shaft is disposed inside the shaft.

3. The overspeed protection device as described in claim 2, characterized in that, The retaining sleeve shaft is connected to the inner wall of the shaft by a toothed connection.

4. The overspeed protection device as described in claim 2, characterized in that, The over-rotation protection device also includes a limiting part disposed on the inner wall of the shaft for limiting the retaining sleeve shaft.

5. The overspeed protection device as described in claim 4, characterized in that, The limiting part includes a stepped structure and / or a retaining ring structure.

6. The overspeed protection device as described in claim 1, characterized in that, The retaining sleeve is fitted onto the outside of the shaft.

7. The overspeed protection device as described in claim 6, characterized in that, The retaining sleeve shaft is fixedly connected to the shaft.

8. The overspeed protection device as described in claim 7, characterized in that, The retaining sleeve is welded to the shaft or connected by fasteners.

9. The overspeed protection device as described in any one of claims 2-8, characterized in that, The retaining sleeve shaft is provided with an energy storage pre-torsion unit, which is used to provide a torque in the opposite direction to the torque generated by the shaft after the shaft breaks.

10. The overspeed protection device as described in claim 9, characterized in that, The energy storage pre-torsion unit includes an elastic energy storage component.

11. The overspeed protection device as described in claim 10, characterized in that, The elastic energy storage component includes a torsion spring or a torsion bar.

12. The overspeed protection device as described in claim 9, characterized in that, The retaining sleeve includes a retaining tube and an energy storage pre-torsion unit. The retaining tube is a cantilever structure, including a fixed end and a free end. At least a portion of the energy storage pre-torsion unit is located inside the retaining tube, so that the retaining tube and the energy storage pre-torsion unit form a double-layer structure. The energy storage pre-torsion unit provides a second end to the retaining sleeve shaft, and the free end is not connected to the second end.

13. The overspeed protection device as described in claim 12, characterized in that, The free end includes a sleeve connecting tooth for connecting with the inner wall sleeve tooth of the shaft. The second end includes an energy storage connecting sleeve for connecting with the inner wall sleeve of the shaft.

14. The overspeed protection device as described in claim 1, characterized in that, The shaft includes multiple locations prone to breakage, and each of these locations is provided with a retaining sleeve shaft.

15. A shaft, characterized in that, Includes the overspeed protection device as described in any one of claims 1-14.

16. An aircraft engine, characterized in that, Includes the shaft as described in claim 15.

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