A method for improving the suction capacity of a lubricating oil pump

Abstract

The present invention discloses a method for improving the suction capacity of an oil pump in the technical field of an aircraft engine oil system. Through steps S1-S3 in the method, the internal dimensions of the oil pump are optimized, the matching clearances between components are optimized, and the separation effect between the oil supply stage and the oil return stage is increased, so as to reduce the amount of cross-flow between the oil supply stage and other oil return stages inside the oil pump, and reduce the amount of cross-flow between the inlet and outlet of the oil supply stage, thereby improving the effect of the suction capacity of the oil pump without changing the external configuration and dimensions of the oil pump, and increasing the diameter of the inlet pipeline of the oil supply stage of the oil pump so that the flow rate of the oil in the pipeline is not higher than 1m / s, so as to reduce flow resistance loss, avoid throttling, and improve the oil supply stability of the oil pump under adverse conditions. Finally, a simulation test system is used to test the suction capacity of the oil pump under low temperature conditions, so as to ensure that the suction capacity of the oil pump can meet the design requirements of the engine and ensure the stable operation of the engine.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engine lubricating oil systems, and in particular to a method for improving the suction capacity of a lubricating oil pump. Background Art

[0002] In the engine design process, the engine will be designed specifically according to the flight envelope proposed by the aircraft so that the engine's performance meets the aircraft's needs. After the engine design and assembly are completed, the engine needs to be tested and verified to ensure that the engine meets the aircraft's needs.

[0003] However, due to the processing errors of engine parts and differences in on-site assembly, the actual performance of the engine may deviate, which may cause the engine performance to fail to meet the aircraft party's requirements during the final test run;

[0004] Especially the lubricating oil pump in the engine lubricating oil system. At present, the lubricating oil tank of small and medium-sized aviation gas turbine shaft engines is usually placed at a low position and the lubricating oil pump is placed at a high position, which will increase the difficulty of the lubricating oil pump to suck. It is easy to cause air plugging due to insufficient suction capacity of the lubricating oil pump, which may cause the friction pairs such as engine bearings and gears to wear and fail due to lack of oil lubrication and cooling. In addition, under extreme low-temperature cold immersion conditions, the viscosity of the lubricating oil increases, and the lubricating oil pump is more likely to have a problem that the suction capacity does not meet the design requirements during actual test runs;

[0005] At this time, if the lubricating oil pump is optimized, it will inevitably lead to changes in the external configuration and size of the lubricating oil pump. However, the compact layout of engine accessories often limits the adjustment space for changes in the external configuration and size of the lubricating oil pump. At this time, it is necessary to re-match the engine accessories and the mounting casing on a large scale, which seriously affects the development progress of the engine.

[0006] The current measure is to control the diameter / inner diameter and length of the lubricating oil pump inlet pipeline / oil circuit, making the length as short as possible, and making the diameter as small as possible under the premise of ensuring that the flow rate does not exceed the standard, so as to reduce the volume of the pipeline before the pump. For the problem of increased viscosity of lubricating oil in low temperature environment, replace the lubricating oil with a low viscosity grade or use an external heating device to heat the engine lubricating oil tank and other parts;

[0007] Measures to control the diameter and length of the oil pump inlet pipeline can ensure the normal operation of the engine at normal temperature. However, due to the small diameter of the pipe, throttling is prone to occur under low temperature conditions, which in turn causes insufficient oil pump outlet flow and low oil pressure alarms. The use of low-viscosity grade oil or external heating devices increases the workload of engine field maintenance and increases the cost of use. At the same time, the traditional low-temperature suction test cannot fully simulate the actual low-temperature use environment of the oil pump, and cannot accurately reflect the suction capacity of the oil pump under actual low-temperature conditions.

[0008] Based on this, the present invention proposes a method for improving the suction capacity of a lubricating oil pump to solve the above-mentioned problem. Summary of the invention

[0009] To achieve the above object, the present invention provides the following technical solution: a method for improving the suction capacity of a lubricating oil pump, characterized in that it comprises the following steps:

[0010] S1, reduce the clearance between the rotor end face of the oil supply stage, the radial clearance between the baffles on both sides of the oil supply stage and the oil well hole, and the radial clearance between the eccentric housing of the oil supply stage and the oil well hole;

[0011] S2, increase the width of the sealing zone between the oil supply stage inlet and the adjacent oil return stage inlet;

[0012] S3, the diameter of the lubricating oil pump oil supply stage inlet pipe is increased;

[0013] S4, the suction capacity of the lubricating oil pump is tested under normal temperature conditions. When the test results of the suction capacity of the lubricating oil pump under normal temperature conditions do not meet the engine design requirements, the process returns to step S1. If the test results meet the engine design requirements, the lubricating oil pump is installed in the simulation test system to test the suction capacity of the lubricating oil pump under low temperature conditions. The accessory layout in the simulation test system is the same as the accessory layout in the engine lubricating oil system. If the test results do not meet the engine design requirements, the process returns to step S1. If the test results meet the engine design requirements, the lubricating oil pump is qualified.

[0014] As a further solution of the present invention, in step S4, the method for testing the suction capacity of the lubricating oil pump under normal temperature conditions includes:

[0015] S411, connecting the lubricating oil pump to the test fixture, and connecting the motor output shaft to the lubricating oil pump shaft;

[0016] S412, install a stop valve on the inlet pipeline of the oil supply stage of the lubricating oil pump to seal the inlet pipeline, and install a negative pressure sensor on the side of the inlet pipeline of the oil supply stage of the lubricating oil pump close to the lubricating oil pump;

[0017] S413, the outlet of the oil supply stage of the lubricating oil pump is directly connected to the atmosphere, and the inlet and outlet of the oil return stage adjacent to the oil supply stage are directly connected to the atmosphere, and the remaining oil return stages are normally connected to the test oil tank to form a circulation loop with the test oil tank;

[0018] S414, start the motor and increase the oil pump shaft speed to 4% of the rated speed. Keep it stable for 1 to 2 minutes, wait for the negative pressure sensor value to stabilize, and record the value after stabilization. The value of the negative pressure sensor after stabilization should be less than the engine design requirement.

[0019] As a further solution of the present invention, the simulation test system includes a test box, a test oil tank, a first flow path and a second flow path;

[0020] The temperature in the test box is adjustable, and the test oil tank, the first flow path and the second flow path are all arranged in the test box;

[0021] The test oil tank comprises a first oil tank and a second oil tank, the first flow path has two ends connected to the oil inlet and the oil outlet of the first oil tank to form a loop, and the second flow path has two ends connected to the oil inlet and the oil outlet of the second oil tank to form a loop;

[0022] The first flow path includes a switch valve, a first pressure tester, a second pressure tester, a flow meter and a regulating valve arranged in sequence along the flow direction of the lubricating oil;

[0023] The second flow path includes several parallel branches arranged in sequence along the flow direction of the lubricating oil, a second pressure tester and a regulating valve. The branches are provided with a switch valve and a first pressure tester in sequence along the flow direction of the lubricating oil. The ends of the several branches close to the second oil tank are directly connected to the second oil tank.

[0024] As a further solution of the present invention, in step S4, the method for testing the suction capacity of the lubricating oil pump under low temperature conditions includes:

[0025] S421, connecting the lubricating oil pump to the test fixture, and connecting the motor output shaft to the lubricating oil pump shaft;

[0026] S422, installing the oil supply stage of the lubricating oil pump between the first pressure tester and the second pressure tester of the first flow path by using a test fixture, wherein the first pressure tester is connected to the inlet of the oil supply stage of the lubricating oil pump, and the second pressure tester is connected to the outlet of the oil supply stage of the lubricating oil pump;

[0027] S423, using a test fixture, several oil return stages of the lubricating oil pump are respectively installed on several branches of the second flow path, a first pressure tester on the branch is connected to an inlet of the oil return stage of the lubricating oil pump, and a second pressure tester on the second flow path is connected to an outlet of all oil return stages of the lubricating oil pump;

[0028] S424, under normal temperature conditions, start the motor, adjust the speed of the lubricating oil pump shaft to the rated state, adjust the regulating valve provided on the first flow path and the regulating valve provided on the second flow path to calibrate the outlet oil path loads of the oil supply stage and the oil return stage of the lubricating oil pump respectively, and after the calibration is completed, turn off the motor to stop the lubricating oil pump shaft;

[0029] S425, start the test chamber cooling system to lower the ambient temperature in the test chamber to the test temperature, and observe the oil temperature sensor installed on the first oil tank to ensure that the cold immersion is in place;

[0030] S426, start the motor to simulate the cold running of the engine with the rotation rate, speed and duration to perform a simulated cold running test, observe and record the time and size of the pressure build-up of the second pressure tester on the first flow path, and record relevant data. After two consecutive simulated cold running tests, the pressure of the second pressure tester on the first flow path should be greater than the engine design requirement;

[0031] S427, the starting motor simulates the motor speed, rotation speed and duration when the engine is started to perform a simulated starting test, observe and record the time and size of the pressure buildup on the second pressure tester on the first flow path, and record relevant data. During the starting process and after starting to slow speed, the pressure of the second pressure tester on the first flow path should be stable and the pressure value should not be lower than the engine low pressure alarm value.

[0032] As a further solution of the present invention, a height-adjustable support frame is installed at the bottom end of the first oil tank to control the height difference between the first oil tank and the lubricating oil pump when the suction capacity of the lubricating oil pump is tested under low temperature conditions.

[0033] As a further solution of the present invention, before testing the suction capacity of the lubricating oil pump under normal temperature conditions and testing the suction capacity under low temperature conditions, the lubricating oil remaining inside the lubricating oil pump to be tested should be cleaned out.

[0034] As a further solution of the present invention, the test tooling includes an adapter and a plurality of oil ports opened on the surface of the adapter for installing a lubricating oil pump, the plurality of oil ports are opened on the same plane of the adapter, the adapter is provided with pipe joints having the same number as the oil ports, and the pipe joints correspond one-to-one to the oil ports.

[0035] As a further solution of the present invention, the end face fitting clearance of the oil supply stage rotor is less than 0.05mm, the radial fitting clearance between the partitions on both sides of the oil supply stage and the oil well hole is less than 0.025mm, the radial fitting clearance between the eccentric housing of the oil supply stage and the oil well hole is less than 0.025mm, and the sealing belt width is greater than 5mm.

[0036] The present invention has the following beneficial effects:

[0037] When the suction capacity of the lubricating oil pump does not meet the design requirements of the engine, the internal dimensions of the lubricating oil pump are optimized through steps S1-S3 of the method, the fitting clearance between the components is optimized, and the separation effect between the oil supply stage and the oil return stage is increased to reduce the amount of cross-talk between the oil supply stage and other oil return stages inside the lubricating oil pump, and reduce the amount of cross-talk between the inlet and outlet of the oil supply stage, thereby improving the suction capacity of the lubricating oil pump without changing the external configuration and size of the lubricating oil pump, and increasing the diameter of the inlet pipeline of the oil supply stage of the lubricating oil pump so that the flow rate of the lubricating oil in the pipe is not higher than 1m / s, so as to reduce flow resistance loss, avoid throttling, and improve the oil supply stability of the lubricating oil pump under harsh conditions. Finally, a simulation test system is used to test the suction capacity of the lubricating oil pump under low temperature conditions to ensure that the suction capacity of the lubricating oil pump can meet the design requirements of the engine and ensure the stable operation of the engine.

[0038] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0040] Figure 1 It is a schematic diagram of the process of the present invention;

[0041] Figure 2 It is a schematic cross-sectional structure diagram of the lubricating oil pump in the present invention;

[0042] Figure 3 It is a schematic diagram of the optimized position of the lubricating oil pump in the present invention;

[0043] Figure 4 It is a schematic diagram of the structure of the adapter in the present invention;

[0044] Figure 5 It is a schematic diagram of the connection between the adapter and the lubricating oil pump in the present invention;

[0045] Figure 6 It is a structural schematic diagram of the simulation test system in the present invention.

[0046] Legend:

[0047] 11. Shell; 12. Oil supply stage; 13. Oil return stage; 14. Rotor; 15. Eccentric shell; 16. Partition; 21. Test box; 22. First oil tank; 23. Second oil tank; 24. Switch valve; 25. First pressure tester; 26. Second pressure tester; 27. Flow meter; 28. Control valve; 29. ​​Oil temperature sensor; 3. Adapter; 31. Oil port; 32. Pipe joint. DETAILED DESCRIPTION

[0048] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0049] See also Figure 1-6 The present invention provides a method for improving the suction capacity of a lubricating oil pump, which is used to increase the suction capacity of the lubricating oil pump without changing the size and configuration of the lubricating oil pump, so as to improve the oil supply stability of the lubricating oil pump under harsh conditions.

[0050] like Figure 2 As shown, the lubricating oil pump in the current aircraft engine generally adopts a multi-stage rotor pump, which includes a housing 11, an oil supply stage 12 and a plurality of oil return stages 13. The oil supply stage 12 and the oil return stage 13 are both arranged in the housing 11, and the oil supply stage 12 and the oil return stage 13 both include a rotor 14 and an eccentric housing 15. The oil supply stage 12 and the oil return stage 13 and the plurality of oil return stages 13 are separated by a partition 16, and the oil supply stage 12 and the multi-stage oil return stages 13 are connected in series through a shaft.

[0051] Specifically, the method for improving the suction capacity of the lubricating oil pump comprises the following steps:

[0052] S1, reduce the end surface fitting clearance L1 of the rotor 14 of the oil supply stage 12, the radial fitting clearance L2 between the baffles 16 on both sides of the oil supply stage 12 and the oil well hole, and the radial fitting clearance L3 between the eccentric shell 15 of the oil supply stage 12 and the oil well hole, wherein the end surface fitting clearance L1 of the rotor 14 of the oil supply stage 12 is less than 0.05mm, which can be achieved by the thickness difference between the rotor 14 of the oil supply stage 12 and the eccentric shell 15, the radial fitting clearance L2 between the baffles 16 on both sides of the oil supply stage 12 and the oil well hole is less than 0.025mm, which can be achieved by the difference in the inner diameter of the through hole oil well hole and the outer diameter of the baffle 16, and the radial fitting clearance L3 between the eccentric shell 15 of the oil supply stage 12 and the oil well hole is less than 0.025mm, which can be achieved by the difference in the inner diameter of the through hole oil well hole and the outer diameter of the eccentric shell 15;

[0053] S2, increase the sealing band width L4 of the oil supply stage 12 inlet and the adjacent oil return stage 13 inlet, the sealing band width L4>5mm;

[0054] S3, the diameter of the lubricating oil pump supply stage 12 inlet pipe is increased;

[0055] S4, the suction capacity of the lubricating oil pump is tested under normal temperature conditions. When the test result of the suction capacity of the lubricating oil pump under normal temperature conditions does not meet the engine design requirements, the process returns to step S1. If the test result meets the engine design requirements, the lubricating oil pump is installed in the simulation test system to test the suction capacity of the lubricating oil pump under low temperature conditions. The accessory layout in the simulation test system is the same as the accessory layout in the engine lubricating oil system. If the test result does not meet the engine design requirements, the process returns to step S1. If the test result meets the engine design requirements, the lubricating oil pump is qualified.

[0056] Through step S1 and step S2, the internal accessories of the lubricating oil pump and the fitting clearances between the accessories are improved, and the separation effect between the oil supply stage 12 and the oil return stage 13 is increased, so as to reduce the amount of cross-flow between the oil supply stage 12 and other oil return stages 13 inside the lubricating oil pump, and reduce the amount of cross-flow between the inlet and outlet of the oil supply stage 12, thereby improving the suction capacity of the lubricating oil pump and improving the oil supply stability of the lubricating oil pump under harsh conditions.

[0057] At the same time, by increasing the diameter of the inlet pipeline of the oil pump supply stage 12, the flow rate of the lubricating oil in the pipe is made no higher than 1m / s, so as to reduce the flow resistance loss and avoid throttling, thereby improving the suction capacity of the lubricating oil pump under low temperature conditions.

[0058] Finally, the suction capacity of the lubricating oil pump under normal temperature conditions and the suction capacity test under low temperature conditions in step S4 are used to determine whether the suction capacity of the lubricating oil pump meets the design requirements of the engine. When the suction capacity of the lubricating oil pump after improvement in the above steps reaches the engine design requirements, the lubricating oil pump meets the requirements. When one of the test results of the suction capacity test of the lubricating oil pump under normal temperature conditions and the suction capacity test under low temperature conditions does not meet the engine design requirements, steps S1-S3 are repeated to optimize the lubricating oil pump again until the results of the suction capacity test of the lubricating oil pump under normal temperature conditions and the suction capacity test of the lubricating oil pump under low temperature conditions both meet the engine design requirements. The suction capacity of the lubricating oil pump under severe flight conditions can be tested by testing the suction capacity of the lubricating oil pump under low temperature conditions, so as to ensure that the lubricating oil pump can normally transport lubricating oil to the engine under low temperature conditions, so as to ensure the safe use of the engine.

[0059] Specifically, in step S4, the method for testing the suction capacity of the lubricating oil pump under normal temperature conditions includes:

[0060] S411, connect the lubricating oil pump to the test fixture, and connect the motor output shaft to the lubricating oil pump shaft, such as Figure 4-5 As shown, the motor and the lubricating oil pump are both installed on the test fixture, and the motor output shaft passes through the test fixture and is fixedly connected to the lubricating oil pump shaft;

[0061] S412, install a stop valve on the inlet pipeline of the oil supply stage 12 of the lubricating oil pump to seal the inlet pipeline, and install a negative pressure sensor on the side of the inlet pipeline of the oil supply stage 12 of the lubricating oil pump close to the lubricating oil pump. After installing the stop valve on the inlet pipeline of the lubricating oil pump, close the stop valve to seal the section of the inlet pipeline of the oil supply stage 12 of the lubricating oil pump from the stop valve to the lubricating oil pump, and install a negative pressure sensor in this sealed section to monitor the pressure in this sealed section. When installing the stop valve, no oil can be stored in the pipeline between the stop valve and the lubricating oil pump, and the volume is as small as possible.

[0062] S413, the outlet of the oil supply stage 12 of the lubricating oil pump is directly connected to the atmosphere, and the inlet and outlet of the oil return stage 13 adjacent to the oil supply stage 12 to be tested are directly connected to the atmosphere to prevent the adjacent oil return stage 13 from running with oil and the lubricating oil from flowing into the oil supply stage 12 through the gap, causing the pumping capacity of the oil supply stage 12 to change. The remaining oil return stages 13 are normally connected to the test oil tank to form a circulation loop with the test oil tank to simulate the real oil return state to ensure the accuracy of the test;

[0063] S414, start the motor and increase the oil pump shaft speed to 4% of the rated speed. If the speed is too low, it cannot reflect the suction performance. If the speed is too high, it will cause wear of the pump rotor 14. Since the inlet pipeline of the oil pump is sealed by the stop valve, the air in the inlet pipeline will be sucked out when the oil pump is working, causing the air pressure in the inlet pipeline to decrease. Stay stable for 1 to 2 minutes. Under normal circumstances, the negative pressure will drop rapidly. Wait for the negative pressure sensor value to stabilize and record the stabilized value. The stabilized value of the negative pressure sensor should be less than the engine design requirement. The smaller the negative pressure, the stronger the suction capacity of the oil pump.

[0064] The above steps realize the inspection of the suction capacity of the lubricating oil pump under normal temperature conditions. The overall inspection method is simple, and the specific value of the suction capacity of the lubricating oil pump under normal temperature conditions can be obtained, and the lubricating oil pump with stronger suction capacity can be screened out.

[0065] Specifically, in step S4, the method for testing the suction capacity of the lubricating oil pump under low temperature conditions needs to be performed in a simulation test system, and the simulation test system includes a test box 21, a test oil tank, a first flow path, and a second flow path;

[0066] The temperature in the test box 21 is adjustable, and the test oil tank, the first flow path and the second flow path are all arranged in the test box 21. By adjusting the temperature in the test box 21, the use state of the engine in a low temperature environment is simulated, so that the suction capacity of the lubricating oil pump is closer to the actual use environment, and the test result is more accurate. In combination with the test method of the suction capacity of the lubricating oil pump under normal temperature conditions, the lubricating oil pump that meets all flight environments in the engine flight envelope can be screened out;

[0067] like Figure 6As shown, the test oil tank includes a first oil tank 22 and a second oil tank 23, the two ends of the first flow path are connected to the oil inlet and the oil outlet of the first oil tank 22 to form a loop, and the two ends of the second flow path are connected to the oil inlet and the oil outlet of the second oil tank 23 to form a loop;

[0068] The number and installation positions of the accessories in the first flow path and the second flow path are the same as the accessory layout of the engine lubricating oil system. At the same time, the length of the connecting pipes between the accessories in the first flow path and the second flow path is also the same as the engine lubricating oil system, so as to restore the actual use environment of the lubricating oil pump to the greatest extent and make the final inspection results more accurate.

[0069] like Figure 6 As shown, the first flow path includes a switch valve 24, a first pressure tester 25, a second pressure tester 26, a flow meter 27 and a regulating valve 28 arranged in sequence along the flow direction of the lubricating oil;

[0070] like Figure 6 As shown, the second flow path includes a plurality of parallel branches arranged in sequence along the flow direction of the lubricating oil, a second pressure tester 26 and a regulating valve 28, a switch valve 24 and a first pressure tester 25 are arranged in sequence along the flow direction of the lubricating oil on the branch, and one end of the plurality of branches close to the second oil tank 23 is directly connected to the second oil tank 23;

[0071] The test methods for the suction capacity of lubricating oil pumps under low temperature conditions include:

[0072] S421, connecting the lubricating oil pump to the test fixture, and connecting the motor output shaft to the lubricating oil pump shaft;

[0073] S422, the oil supply stage 12 of the lubricating oil pump is installed between the first pressure tester 25 and the second pressure tester 26 of the first flow path through the test fixture, the first pressure tester 25 is connected to the inlet of the lubricating oil supply stage 12 of the lubricating oil pump, and the second pressure tester 26 is connected to the outlet of the lubricating oil supply stage 12 of the lubricating oil pump. The lubricating oil is extracted from the first oil tank 22 through the lubricating oil supply stage 12 and sent out to simulate the actual oil supply;

[0074] S423, several oil return stages 13 of the lubricating oil pump are respectively installed on several branches of the second flow path through the test fixture, the first pressure tester 25 on the branch is connected to the inlet of the lubricating oil pump return stage 13, the second pressure tester 26 on the second flow path is connected to the outlets of all the oil return stages 13 of the lubricating oil pump, and the lubricating oil is extracted from the second oil tank 23 through the oil return stage 13 of the lubricating oil pump and sent out to simulate the real oil return;

[0075] S424, under normal temperature conditions, start the motor, adjust the speed of the lubricating oil pump shaft to the rated state, and adjust the regulating valve 28 set on the first flow path and the regulating valve 28 set on the second flow path to calibrate the outlet oil path loads of the lubricating oil pump oil supply stage 12 and the oil return stage 13 respectively, so as to truly simulate the outlet resistance of the lubricating oil pump when working on the engine. After the calibration is completed, turn off the motor to stop the lubricating oil pump shaft;

[0076] S425, start the cooling system of the test box 21 to reduce the ambient temperature in the test box 21 to the test temperature, and observe the oil temperature sensor 29 installed on the first oil tank 22 to ensure that the cold soaking is in place;

[0077] S426, start the motor to simulate the cold running of the engine with the rotation rate, speed and duration to perform a simulated cold running test, observe and record the time and size of the pressure build-up of the second pressure tester 26 on the first flow path, and record relevant data. After two consecutive simulated cold running tests, the pressure read by the second pressure tester 26 on the first flow path should be greater than the engine design requirement;

[0078] S427, the starting motor simulates the motor rotation rate, speed and duration when the engine is started to perform a simulated starting test, simulate the working environment of the lubricating oil pump when the aircraft is started, observe and record the time and size of the pressure buildup on the second pressure tester 26 on the first flow path, and record relevant data. During the starting process and after starting to slow speed, the pressure of the second pressure tester 26 on the first flow path should be stable and the pressure value should not be lower than the low pressure warning value specified in the engine design.

[0079] When the engine is operating normally, the lubricating oil in the oil tank will circulate between the engine and the oil tank through the oil pump. As a result, the lubricating oil will exchange heat with the high-temperature parts in the engine that are in contact with the lubricating oil to maintain a normal temperature. When the engine is running cold or starting, the lubricating oil in the oil tank is not circulated, so the lubricating oil in the oil tank will be close to the ambient temperature of the aircraft parking area. Therefore, during the entire flight of the aircraft, the lubricating oil temperature in the oil tank is the lowest when the aircraft is in the cold operation state and the starting state, which is also the worst working state of the oil pump.

[0080] By simulating the worst operating environment of the lubricating oil pump, the suction capacity of the lubricating oil pump under the worst operating environment is tested. If the suction capacity of the lubricating oil pump at this time meets the engine design requirements, it proves that the current lubricating oil pump can meet the engine's demand for lubricating oil supply under all conditions in the aircraft's flight envelope, and can ensure the normal operation of the engine to ensure flight safety.

[0081] In some examples, a height-adjustable support frame is installed at the bottom of the first oil tank 22 to control the height difference between the first oil tank 22 and the lubricating oil pump when testing the suction capacity of the lubricating oil pump under low temperature conditions, thereby improving the degree of restoration of the use environment of the lubricating oil pump, making the final test result closer to the actual result, and making the test result more accurate. The height-adjustable support frame is a prior art in the field and will not be elaborated here.

[0082] Specifically, before testing the suction capacity of the lubricating oil pump under normal temperature conditions and the suction capacity under low temperature conditions, the lubricating oil remaining inside the lubricating oil pump to be tested should be cleaned up. There are two specific cleaning methods:

[0083] First, drain the lubricating oil of the oil pump to be tested as much as possible by inverting it, etc., then fill the lubricating oil pump to be tested with gasoline, manually turn the lubricating oil pump shaft repeatedly, use gasoline to dilute the small amount of lubricating oil remaining in the pump, and then drain the gasoline.

[0084] Before assembling the lubricating oil pump to be tested, all components are cleaned and no lubricating oil is applied during the assembly process to ensure that after the pump is assembled, there is no remaining lubricating oil inside the pump and it is in a dry rotor 14 state.

[0085] The test fixture includes an adapter 3 and a plurality of oil ports 31 for installing a lubricating oil pump on the surface of the adapter 3, such as Figure 4 As shown, the adapter 3 is provided with a flat plane, and a plurality of oil ports 31 are all opened on this plane, that is, when the lubricating oil pump is installed on the adapter 3, the oil port of the lubricating oil pump and the oil port 31 of the adapter 3 are end-to-end butted to reduce external pipelines and improve the integration of the oil circuit. The side surface of the adapter 3 on which the oil ports 31 are opened is also provided with pipe joints 32 having the same number as the oil ports 31. The pipe joints 32 correspond to the oil ports 31 one by one, so as to be easily connected with the test pipeline.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, 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 method for improving the suction capacity of a lubricating oil pump, characterized in that: The following steps are involved: S1, reduce the clearance between the rotor end face of the oil supply stage, the radial clearance between the baffles on both sides of the oil supply stage and the oil well hole, and the radial clearance between the eccentric housing of the oil supply stage and the oil well hole; S2, increase the width of the sealing zone between the oil supply stage inlet and the adjacent oil return stage inlet; S3, the diameter of the lubricating oil pump oil supply stage inlet pipe is increased; S4, the suction capacity test of the lubricating oil pump under normal temperature conditions. If the test results of the suction capacity of the lubricating oil pump under normal temperature conditions do not meet the engine design requirements, the process returns to step S1. If the test results all meet the engine design requirements, the lubricating oil pump is installed in the simulation test system to test the suction capacity of the lubricating oil pump under low temperature conditions. If the test results do not meet the engine design requirements, the process returns to step S1. If the test results all meet the engine design requirements, the lubricating oil pump is qualified. Test the suction capacity of the lubricating oil pump under normal temperature conditions: connect the motor output shaft to the lubricating oil pump shaft, install a stop valve on the inlet pipeline of the lubricating oil pump supply stage to seal the inlet pipeline, and install a negative pressure sensor on the side of the inlet pipeline of the lubricating oil pump supply stage close to the lubricating oil pump, turn on the motor, and wait for the negative pressure sensor value to stabilize; The simulation test system comprises a test box, a test oil tank, a first flow path and a second flow path. The temperature inside the test box can be adjusted, and the test oil tank, the first flow path and the second flow path are all arranged in the test box. The test oil tank comprises a first oil tank and a second oil tank. Two ends of the first flow path are connected to the oil inlet and the oil outlet of the first oil tank to form a loop. Two ends of the second flow path are connected to the oil inlet and the oil outlet of the second oil tank to form a loop. The first flow path comprises a switch valve, a first pressure tester, a second pressure tester, a flow meter and a regulating valve arranged in sequence along the flow direction of the lubricating oil. The second flow path comprises a plurality of parallel branches arranged in sequence along the flow direction of the lubricating oil, a second pressure tester and a regulating valve. The branches are provided with a switch valve and a first pressure tester in sequence along the flow direction of the lubricating oil. One end of the plurality of branches close to the second oil tank is directly connected to the second oil tank. Inspection of the lubricating oil pump's suction capacity under low temperature conditions: S421, connecting the lubricating oil pump to the test fixture, and connecting the motor output shaft to the lubricating oil pump shaft; S422, installing the oil supply stage of the lubricating oil pump between the first pressure tester and the second pressure tester of the first flow path by using a test fixture, wherein the first pressure tester is connected to the inlet of the oil supply stage of the lubricating oil pump, and the second pressure tester is connected to the outlet of the oil supply stage of the lubricating oil pump; S423, using a test fixture, several oil return stages of the lubricating oil pump are respectively installed on several branches of the second flow path, a first pressure tester on the branch is connected to an inlet of the oil return stage of the lubricating oil pump, and a second pressure tester on the second flow path is connected to an outlet of all oil return stages of the lubricating oil pump; S424, under normal temperature conditions, start the motor, adjust the speed of the lubricating oil pump shaft to the rated state, adjust the regulating valve provided on the first flow path and the regulating valve provided on the second flow path to calibrate the outlet oil path loads of the oil supply stage and the oil return stage of the lubricating oil pump respectively, and after the calibration is completed, turn off the motor to stop the lubricating oil pump shaft; S425, start the cooling system of the test chamber to reduce the ambient temperature in the test chamber to the test temperature, and observe the oil temperature sensor installed on the first oil tank to ensure that the cold immersion is in place; S426, start the motor to simulate the cold running of the engine with the rotation rate, speed and duration to perform a simulated cold running test, observe and record the time and size of the pressure build-up of the second pressure tester on the first flow path, and record relevant data. After two consecutive simulated cold running tests, the pressure of the second pressure tester on the first flow path should be greater than the engine design requirement; S427, the starting motor simulates the motor speed, rotation speed and duration when the engine is started to perform a simulated starting test, observe and record the time and size of the pressure buildup on the second pressure tester on the first flow path, and record relevant data. During the starting process and after starting to slow speed, the pressure of the second pressure tester on the first flow path should be stable and the pressure value should not be lower than the engine low pressure alarm value.

2. A method for improving the suction capacity of a lubricating oil pump according to claim 1, characterized in that: In step S4, the method for testing the suction capacity of the lubricating oil pump under normal temperature conditions includes: S411, connecting the lubricating oil pump to the test fixture, and connecting the motor output shaft to the lubricating oil pump shaft; S412, install a stop valve on the inlet pipeline of the oil supply stage of the lubricating oil pump to seal the inlet pipeline, and install a negative pressure sensor on the side of the inlet pipeline of the oil supply stage of the lubricating oil pump close to the lubricating oil pump; S413, the outlet of the oil supply stage of the lubricating oil pump is directly connected to the atmosphere, and the inlet and outlet of the oil return stage adjacent to the oil supply stage are directly connected to the atmosphere, and the remaining oil return stages are normally connected to the test oil tank to form a circulation loop with the test oil tank; S414, start the motor to increase the oil pump shaft speed to 4% of the rated speed, stay stable for 1 to 2 minutes, wait for the negative pressure sensor value to stabilize, and record the stabilized value. The stabilized value of the negative pressure sensor should be less than the engine design requirement.

3. The method for improving the suction capacity of a lubricating oil pump according to claim 1, characterized in that: A height-adjustable support frame is installed at the bottom end of the first oil tank to control the height difference between the first oil tank and the lubricating oil pump when the suction capacity of the lubricating oil pump is tested under low temperature conditions.

4. The method for improving the suction capacity of a lubricating oil pump according to claim 1, characterized in that: Before testing the suction capacity of the lubricating oil pump under normal temperature conditions and under low temperature conditions, the lubricating oil remaining inside the lubricating oil pump to be tested should be cleaned out.

5. The method for improving the suction capacity of a lubricating oil pump according to claim 1, characterized in that: The test tooling includes an adapter and a plurality of oil ports opened on the surface of the adapter for installing a lubricating oil pump. The plurality of oil ports are opened on the same plane of the adapter. The adapter is provided with pipe joints having the same number as the oil ports, and the pipe joints correspond one-to-one to the oil ports.

6. The method for improving the suction capacity of a lubricating oil pump according to claim 1, characterized in that: The end face fit clearance of the oil supply stage rotor is <0.05mm, the radial fit clearance between the baffles on both sides of the oil supply stage and the oil well hole is <0.025mm, the radial fit clearance between the eccentric housing of the oil supply stage and the oil well hole is <0.025mm, and the width of the sealing belt is >5mm.

Images