Troubleshooting Method for Abnormal Torque Swing of Turboshaft Engine

Abstract

The present invention discloses a method for troubleshooting abnormal torque swing in a turboshaft engine. The turboshaft engine includes an accessory casing unit and a reducer unit connected to each other. The reducer unit includes a reducer casing and an intermediate gear. The reducer unit is provided with a torque measuring mechanism. The torque measuring mechanism includes a plunger. The plunger is installed in the inner hole of the intermediate gear via a bearing. The end of the plunger and the inner surface of the reducer casing enclose a plunger cavity. The method for troubleshooting abnormal torque swing is to change the installation position of a torque pressure sensor. The newly installed position of the torque pressure sensor satisfies the requirement that the torque pressure sensor can directly measure the oil pressure in the plunger cavity. The turboshaft engine is then subjected to a level flight test to monitor the torque swing feedback from the torque pressure sensor after the installation position is changed. This troubleshooting method can quickly and accurately determine the fault location, avoid returning the engine to the factory, and has good economic and social benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation engine troubleshooting, and in particular to a method for troubleshooting abnormal torque swing of a turboshaft engine. Background Art

[0002] The turboshaft engine uses a mechanical hydraulic torque measurement method to measure torque. The measurement system mainly consists of a torque measuring mechanism, a torque pressure sensor, a monitoring cable and an indicator. The torque meter is a cockpit instrument. The torque pressure sensor converts the pressure signal into an electrical signal and displays the current torque as a percentage of the calibrated torque through a dial indicator. The torque measuring mechanism is the main part of the torque measurement system. Figure 2 and Figure 4 、 Figure 5 As shown, the torque measuring mechanism 3 is located in the engine reducer unit 1, and the torque pressure sensor is located in the accessory casing unit 2.

[0003] The turboshaft engine reducer unit 1 reduces speed through two-stage helical gears and transmits the torque load to the engine power output shaft. Figure 4 As shown, the reducer unit body 1 includes a reducer casing 11 and an intermediate gear 12, and the torque measuring mechanism 3 is arranged on the reducer unit body 1. The torque measuring mechanism 3 includes a plunger 31, and the plunger 31 is installed in the inner hole of the intermediate gear 12 through a triple bearing 13. The end of the plunger 31 and the inner surface of the reducer casing 11 enclose a plunger cavity 4.

[0004] During operation, the intermediate gear 12 is subjected to a forward axial force, which is transmitted to the plunger 31 through the triple bearing 13. Lubricating oil enters the plunger cavity 4, pushing the plunger 31 rightward, thereby maintaining a balance with the axial force of the intermediate gear 12. When the thrust of the lubricating oil on the plunger 31 is less than the axial force of the intermediate gear 12, the plunger 31 and the intermediate gear 12 move leftward, the gap 15 between the end surface of the plunger 31 and the lubrication duct 14 decreases, the lubricating oil leakage in the plunger cavity 4 decreases, and the lubricating oil pressure increases until the force on the plunger 31 is balanced. Conversely, when the plunger 31 moves rightward, the gap 15 between the end surface of the plunger 31 and the lubrication duct 14 increases, the lubricating oil leakage in the plunger cavity 4 increases, and the lubricating oil pressure decreases until the force on the plunger 31 is balanced.

[0005] The reducer unit 1 and the accessory casing unit 2 are connected through a torque oil pipe 6 to measure the pressure fluctuation in the plunger cavity 4, thereby feeding back the torque swing of the turboshaft engine. Figure 5As shown, the accessory casing unit body 2 is provided with an oil pressure chamber 21 behind the oil pump, and the accessory casing unit body is provided with a mounting hole at the oil pressure chamber 21 behind the oil pump, and a pressure measuring channel 5 is provided on the wall of the mounting hole. The first end of the torque oil pipe 6 is arranged in the mounting hole, and the pressure measuring channel 5 and the torque oil pipe 6DE pipeline are connected. The first end of the torque oil pipe 6 is provided with a sealing ring 61 and contacts the inner wall of the mounting hole to prevent the lubricating oil in the oil pressure chamber 21 behind the oil pump from entering the pressure measuring channel 5; the second end of the torque oil pipe 6 and the plunger cavity 4 form an oil passage.

[0006] The current detection of turboshaft engine torque swing is as follows Figure 5 As shown, this is achieved by sensing the oil pressure in the pressure measuring channel through the torque sensor on the accessory casing unit, thereby indirectly sensing the oil pressure in the plunger cavity of the reducer unit.

[0007] When the turboshaft engine is running on the ground, the engine torque value is normal. However, as the helicopter is in level flight, when the gas turbine speed Ng is between 82% and 84%, the torque value indicated on the engine parameter display fluctuates by approximately 10%, or even 20%, indicating abnormal fluctuations. Other parameters such as the engine's Ng, T4, and Np are normal. This abnormal torque fluctuation problem frequently occurs in level flight and has persisted for many years without being resolved. During this period, a series of troubleshooting measures were implemented, including:

[0008] (1) Clean the torque sensor mounting seat;

[0009] (2) Replace the engine monitoring cable;

[0010] (3) The left and right engine reducer units are interchangeable;

[0011] (4) Make a dedicated cable to connect the torque sensor directly to the engine parameter collector;

[0012] (5) Replacement of helicopter engine parameter indicators several times;

[0013] (6) The torque sensor was replaced several times and the torque sensor plug on the monitoring cable was reinstalled.

[0014] However, after the above measures were implemented, the abnormal torque swing problem would reappear after the helicopter had flown only 2 to 3 sorties, and the fault was never improved, which posed a great risk to the safe operation of the helicopter.

[0015] After consulting various documents, there is currently no relevant literature on the solution to the problem of abnormal torque swing of turboshaft engines. Patent publication number CN103542965A discloses a torque measurement system and torque calibration method for the output shaft of a turboshaft engine. Although the patent measures and calibrates torque, its measurement object is the output shaft, and does not involve problems such as abnormal torque swing. It cannot provide a relevant reference solution for the abnormal torque swing of the turboshaft engine. Summary of the Invention

[0016] The technical problem to be solved by the present invention is to provide a method for troubleshooting abnormal torque swing of a turboshaft engine in view of the defects of the prior art.

[0017] The purpose of the present invention is achieved through the following technical solutions:

[0018] A method for troubleshooting abnormal torque swing of a turboshaft engine. The turboshaft engine includes an accessory casing unit and a reducer unit that are connected to each other. The reducer unit includes a reducer casing and an intermediate gear. The reducer unit is provided with a torque measuring mechanism. The torque measuring mechanism includes a plunger. The plunger is installed in the inner hole of the intermediate gear through a bearing. The end of the plunger and the inner surface of the reducer casing enclose a plunger cavity.

[0019] The accessory casing unit body has an oil pressure cavity behind the oil pump, and the accessory casing unit body is provided with a mounting hole at the oil pressure cavity behind the oil pump, and a pressure measuring channel is provided at the wall of the mounting hole. The turboshaft engine also includes a torque oil pipe, the first end of the torque oil pipe is provided at the mounting hole, and the second end and the plunger cavity form an oil passage, the pressure measuring channel and the torque oil pipe are connected, and the first end of the torque oil pipe is provided with a sealing ring in contact with the inner wall of the mounting hole to prevent the lubricating oil in the oil pressure cavity behind the oil pump from entering the pressure measuring channel.

[0020] The torque swing of the turboshaft engine is fed back by monitoring the pressure change in the plunger cavity using a torque pressure sensor; the method for troubleshooting abnormal torque swing is to change the installation position of the torque pressure sensor, and the new installation position of the torque pressure sensor satisfies: the torque pressure sensor can directly measure the oil pressure in the plunger cavity; then the turboshaft engine is subjected to a level flight test to monitor the torque swing fed back by the torque pressure sensor after the installation position is changed.

[0021] Furthermore, the torque pressure sensor is mounted on a process hole at the intermediate gear of the reducer unit body, the process hole being in communication with the plunger cavity oil path. Preferably, the process hole is located downstream of the plunger cavity of the reducer unit body.

[0022] Furthermore, before conducting a level flight test of the turboshaft engine, a ground test is first conducted to monitor whether the turboshaft engine has abnormal torque swings.

[0023] Furthermore, if the torque feedback from the torque pressure sensor after the installation position is changed has no abnormal swing, the torque oil pipe is replaced so that the sealing ring at the first end of the torque oil pipe and the inner wall of the installation hole are tightly sealed.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] By adopting the troubleshooting method of the present invention, when there is no problem with the torque system accessories, the pressure in the plunger cavity is directly detected by the torque pressure sensor, and the torque oil pipe installation position on the accessory casing unit is isolated, so the fault location can be quickly and accurately determined. That is, it is possible to accurately locate and judge whether the abnormal torque swing is related to the fault of the torque oil pipe itself inside the engine in the field, thereby eliminating the difficult fault of abnormal torque swing of this type of turboshaft engine and avoiding the engine from being returned to the factory, which has good economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the connection of the torque pressure sensor in the troubleshooting method described in Example 1;

[0027] Figure 2 Schematic diagram of the structure of the turboshaft engine torque measurement system in the background technology;

[0028] Figure 3 It is a connection diagram of the torque pressure sensor in the background technology;

[0029] Figure 4 A schematic structural diagram of the torque measuring mechanism described in the background technology and embodiment 1;

[0030] Figure 5 It is a schematic diagram of the installation of the torque pressure sensor and the torque oil pipe in the background technology. DETAILED DESCRIPTION

[0031] In order to clearly illustrate the technical features of this solution, the technical solution is described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0033] In addition, in the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0034] In this application, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0035] In this application, unless otherwise expressly specified and limited, a first feature "above" or "below" a second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0036] Example 1

[0037] A turboshaft engine exhibits torque swing only in helicopter level flight, while other parameters are normal, and the abnormal torque swing cannot be eliminated by replacing accessories. This embodiment constructs a method for troubleshooting abnormal torque swing, specifically a method for isolating the accessory casing unit for torque detection.

[0038] like Figure 1 As shown, the turboshaft engine includes a reducer unit body 1 and an accessory casing unit body 2 connected to each other. Figure 4 In the figure, the reducer unit 1 includes a reducer casing 11 and an intermediate gear 12. The reducer unit 11 is provided with a torque measuring mechanism 3. The torque measuring mechanism 3 includes a plunger 31. The plunger 31 is installed in the inner hole of the intermediate gear 12 through a triple bearing 13. The end of the plunger 31 and the inner surface of the reducer casing 11 enclose a plunger cavity 4.

[0039] like Figure 5 As shown, the accessory casing unit body 2 has an oil pressure chamber 21 behind the oil pump, and the accessory casing unit body 2 is provided with a mounting hole at the oil pressure chamber 21 behind the oil pump, and a pressure measuring channel 5 is provided on the wall of the mounting hole. The turboshaft engine also includes a torque oil pipe 6, the first end of the torque oil pipe 6 is arranged at the mounting hole, and the second end and the plunger cavity 4 form an oil passage, and the pressure measuring channel 5 and the torque oil pipe 6 are connected by a pipeline. The pressure measuring channel 5 is the oil pressure channel for the original torque pressure sensor of the turboshaft engine to indirectly measure the pressure change in the plunger cavity 4, that is, the original torque pressure sensor is installed on the accessory casing unit body; the first end of the torque oil pipe 6 is provided with a sealing ring 61 and contacts the inner wall of the mounting hole. The sealing effect of the sealing ring 61 makes the pressure measuring channel 5 a sealed chamber, and it is necessary to prevent the lubricating oil in the oil pressure chamber 21 behind the oil pump from entering the pressure measuring channel 5, and at the same time, prevent the pressure oil in the torque oil pipe 6 from leaking.

[0040] The method for troubleshooting abnormal torque swing in this embodiment is as follows: Figure 1 As shown, the installation position of the torque pressure sensor 7 is changed. That is, the torque pressure sensor originally installed on the accessory housing unit 2 is removed and installed in a new location. The new installation position of the torque pressure sensor 7 must be sufficient to directly measure the oil pressure in the plunger cavity 4, without indirectly detecting the pressure in the plunger cavity 4 through the torque oil pipe 6 and pressure measurement channel 5. The original installation position of the torque pressure sensor on the accessory housing unit is blocked with a plug.

[0041] Given the abnormal torque fluctuations while other engine parameters remained stable, after extensive troubleshooting, the fluctuations were narrowed down to the engine's torque measurement system. This suggests that the torque measurement system was experiencing interference, while the engine's torque measurement accessories were functioning normally. The present invention further narrowed the interference to pressure fluctuations within pressure measurement channel 5. This pressure fluctuation is believed to be caused by a defective seal ring 61 on the torque oil pipe, which allowed oil from the oil pump's rear oil pressure chamber 21 to enter the seal chamber. This oil, when combined with the oil pressure within pressure measurement channel 5, disrupted the stability of the measured value, resulting in the torque fluctuations measured by the original torque sensor.

[0042] This embodiment eliminates the problem of damaged torque oil pipe seal ring by isolating the accessory casing unit 2. Preferably, the torque pressure sensor 7 is installed on the existing process hole at the intermediate gear 12 of the reducer unit (normally, the process hole is sealed by a process plug, and the process hole cannot be displayed in the viewing direction of the accompanying drawing, so it is not shown). The process hole is located downstream of the plunger cavity 4 of the reducer unit, and the process hole and the plunger cavity 4 are in oil communication. After the torque pressure sensor 7 is connected to the process hole, it directly senses the pressure of the plunger cavity 4. The pressure formed by the movement of the plunger 31 is the torque change of the turboshaft engine. The engine monitoring cable is connected to an oscilloscope or a helicopter engine parameter collector to monitor the engine torque swing in real time. The turboshaft engine is then subjected to ground test and level flight test in sequence to monitor whether the torque pressure sensor 7 after the installation position is changed reports abnormal torque swing.

[0043] If there is no abnormal torque swing during the ground test and the level flight test, the abnormal torque swing fault location can be directly located at the torque oil pipe sealing ring 61.

[0044] The following describes the design mechanism of this method for troubleshooting abnormal torque swing:

[0045] Calculation of the relationship between lubricating oil pressure and output power:

[0046] The output power of a turboshaft engine is reflected by measuring the lubricating oil modulation pressure. The lubricating oil modulation pressure is converted into an electrical signal by a torque pressure sensor and amplified for measurement.

[0047] The relationship between the oil modulation pressure P and the engine output power Nout is derived below:

[0048] Derivation of the relationship between torque T and lubricating oil pressure P

[0049] P*A+f=Fa Formula (1)

[0050] Where: P——oil modulation pressure in "A" cavity, Pa; A——piston end surface area, m 2 ;

[0051] f——additional resistance, N; Fa——axial force on the intermediate gear, N;

[0052] Axial force of the first stage helical teeth of the intermediate gear:

[0053] Second stage helical gear axial force:

[0054] Axial force of helical cylindrical gear: Fa=Fa2-Fa1 (4)

[0055] Where: T1, T2 - torque transmitted by the intermediate gear and the small gear, N m

[0056] d1, d2——Intermediate gear large and small gear pitch circle diameter, mm

[0057] β1, β2——helix angle of the intermediate gear (99) and small gear (33);

[0058] Torque transmitted by the intermediate gear: T1 = T2 = 9549 * N axis / n1 Formula (5)

[0059] The actual measured output torque T is: T = 9549 * N axis / n2 Formula (6)

[0060] Where: N-axis - power transmitted by the reducer, excluding mechanical losses, is the engine output power, kW; n1 - intermediate gear speed, rpm; n2 - speed of the hydraulic dynamometer shaft, connected to the output gear shaft via an internal spline, with the same speed, rpm; T - engine torque, Nm;

[0061] Substituting equations (2), (3), (4), (5), and (6) into equation (1), we obtain:

[0062]

[0063] Deformation of formula (6)

[0064]

[0065] Formula (7) can be rewritten as

[0066]

[0067] Substituting the data, we can get

[0068] T=0.20856P +0.61856f Formula (10)

[0069] (T is in daN.m, P is in KPa)

[0070] Finally, according to formula 10, it can be concluded that the torque T is proportional to the pressure P, that is, the greater the torque, the greater the pressure generated.

[0071] When the engine is running on the ground, the torque pressure is small, and the oil in the oil pressure chamber 21 behind the lubricating oil pump does not enter the pressure measuring channel 5, which has no effect on the torque measurement; when the engine is in a level flight state, the engine torque increases and the torque pressure increases. The oil in the oil pressure chamber 21 behind the lubricating oil pump enters the pressure measuring channel 5 due to the damage of the torque oil pipe sealing ring 61, causing the torque measurement to swing.

[0072] If the torque pressure sensor's installation position is changed and no abnormal torque oscillation is observed during level flight testing, the torque oil pipe 6 needs to be replaced to ensure a tight seal between the intact seal ring 61 at the first end of the torque oil pipe and the inner wall of the mounting hole. Torque oscillation can still be measured using traditional torque measurement methods during subsequent turboshaft engine service.

[0073] The present invention tested and verified the above-mentioned troubleshooting method on multiple turboshaft engines. After an abnormal torque swing fault occurred, the above-mentioned troubleshooting method was used to locate the fault as a damaged sealing ring on the torque oil pipe. By disassembling the engine, it was found that the sealing ring on the torque oil pipe was indeed in a torn state, and the rubber that fell off was adhered to the torque oil pipe mounting hole. This further showed that the damage to the sealing ring affected the sealing between the torque oil pipe and the accessory casing unit. When the helicopter was in level flight, the oil pressure after the lubricating oil pump increased and seeped into the pressure measurement channel from the damaged part of the sealing ring, causing the pressure measurement channel to be disturbed and fluctuating, which was ultimately reflected as torque value fluctuations on the comprehensive display. After replacing the torque oil pipe with an intact sealing ring, the traditional torque measurement method was used to detect the torque swing of the turboshaft engine in the helicopter's level flight state, and no abnormalities were found.

[0074] The troubleshooting method of the present invention can quickly and accurately determine the fault location in the field when there is no problem with the torque system accessories, and eliminate the difficult fault of abnormal torque swing of the turboshaft engine without the need to spend huge costs to return to the factory for troubleshooting. The troubleshooting method can also be applied to the same type of engines, with good economic and social benefits.

[0075] Example 2

[0076] This embodiment provides an operation description for replacing the torque oil pipe:

[0077] 1. Before installing the torque oil pipe, check whether the mounting hole has chamfers and burrs. If chamfers are missing, add chamfers. If burrs are present, remove them.

[0078] 2. Check the integrity of the sealing ring of the torque oil pipe and lubricate the sealing ring;

[0079] 3. The torque oil pipe must be installed vertically and aligned with the mounting hole;

[0080] 4. After installing the torque oil pipe, gently rotate the torque oil pipe to ensure that its sealing ring is not curled in the installation hole.

[0081] Example 3

[0082] Based on Example 2, this embodiment specifies the lubricating material for the lubricating sealing ring, specifically using Turbo-10 grease to lubricate the sealing ring.

[0083] Obviously, the above embodiments are merely examples for the purpose of clearly illustrating the technical solutions of the present invention, and are not intended to limit the implementation methods of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. 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 claims of the present invention.

Claims

1. A method for troubleshooting abnormal torque swing in a turboshaft engine. The turboshaft engine comprises an interconnected accessory casing unit and a reducer unit. The reducer unit comprises a reducer casing and an intermediate gear. The reducer unit is provided with a torque measuring mechanism comprising a plunger mounted within an inner bore of the intermediate gear via a bearing. The end of the plunger and the inner surface of the reducer casing enclose a plunger cavity. The accessory casing unit body has an oil pressure cavity behind the oil pump, the accessory casing unit body is provided with a mounting hole at the oil pressure cavity behind the oil pump, a pressure measuring channel is provided at the wall of the mounting hole, the turboshaft engine further comprises a torque oil pipe, a first end portion of the torque oil pipe is provided at the mounting hole, a second end portion and the plunger cavity form an oil passage, the pressure measuring channel is connected to the torque oil pipe pipeline, a sealing ring is provided at the first end portion of the torque oil pipe and contacts the inner wall of the mounting hole, so as to prevent the lubricating oil in the oil pressure cavity behind the oil pump from entering the pressure measuring channel; The torque swing of the turboshaft engine is fed back by monitoring the pressure change in the plunger cavity using a torque pressure sensor; It is characterized in that The method for troubleshooting abnormal torque swing is to change the installation position of the torque pressure sensor, which is installed on the process hole at the intermediate gear of the reducer unit, and the process hole is connected to the plunger cavity oil circuit; the new installation position of the torque pressure sensor satisfies: the torque pressure sensor can directly measure the oil pressure in the plunger cavity; then the turboshaft engine is subjected to a level flight test to monitor the torque swing fed back by the torque pressure sensor after the installation position is changed; when there is no problem with the torque system accessories, the pressure in the plunger cavity is directly detected by the torque pressure sensor, and the torque oil pipe installation position on the accessory casing unit is isolated, so that the torque abnormal swing can be accurately located and judged in the field whether it is related to the fault of the torque oil pipe itself inside the engine.

2. The method for troubleshooting abnormal torque swing of a turboshaft engine according to claim 1, characterized in that: The process hole is located downstream of the plunger cavity of the reducer unit.

3. The method for troubleshooting abnormal torque swing of a turboshaft engine according to claim 1, characterized in that: After sensing the plunger cavity pressure, the torque pressure sensor feeds back the torque swing condition through an oscilloscope or a parameter collector.

4. The method for troubleshooting abnormal torque swing of a turboshaft engine according to claim 1, characterized in that: Before conducting a level flight test on the turboshaft engine, a ground test is first carried out to monitor whether the turboshaft engine has abnormal torque swings.

5. The method for troubleshooting abnormal torque swing of a turboshaft engine according to claim 1, characterized in that: If the torque feedback from the torque pressure sensor has no abnormal swing after the installation position is changed, replace the torque oil pipe so that the sealing ring at the first end of the torque oil pipe and the inner wall of the installation hole are tightly sealed.

6. The method for troubleshooting abnormal torque swing of a turboshaft engine according to claim 5, characterized in that: The torque tube should be installed vertically and aligned with the mounting hole.

7. The method for troubleshooting abnormal torque swing of a turboshaft engine according to claim 5, characterized in that: Before installing the torque oil pipe, remove the burrs in the installation hole and check the integrity of the sealing ring on the torque oil pipe.

8. The method for troubleshooting abnormal torque swing of a turboshaft engine according to claim 7, characterized in that: When installing the torque oil pipe, lubricate the sealing ring with Turbo-10 grease.

9. The method for troubleshooting abnormal torque swing of a turboshaft engine according to claim 7, characterized in that: After installing the torque tube, rotate the torque tube to prevent the seal from curling in the mounting hole.

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