Gear pair for testing the load-carrying capacity of lubricating oil for aircraft turbine engines
By improving the displacement coefficients of the FZG-CR large gear and FZG-CR small gear, the problem of the inability to accurately assess the lubricating oil load-bearing capacity of aero-turbine engines in the existing technology has been solved, realizing a more efficient and economical testing method and reducing the risk of equipment damage.
Patent Information
- Application Number
- CN202210970273.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-08-12
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2042-08-12
AI Technical Summary
The existing technology lacks methods other than the Ryder gear testing machine to evaluate the load-bearing capacity of aero-turbine engine lubricating oil under high gear speeds and high loads, resulting in high testing costs and inaccurate results.
An improved FZG-CR large gear and FZG-CR small gear were used as the gear pair for testing the lubricating oil load-carrying capacity of aero-turbine engines. By adjusting the displacement coefficient and other parameters of the gear pair, the load-carrying capacity of the lubricating oil could be evaluated more accurately on the high-speed FZG gear testing machine.
It improves the accuracy and reliability of lubricating oil load-bearing capacity testing, reduces testing costs, minimizes damage to testing equipment, and meets the testing requirements of SAE AS5780.
Smart Images
Figure CN115163785B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lubricating oil testing technology, and more specifically to a gear pair for testing the load-bearing capacity of lubricating oil in aircraft turbine engines. Background Technology
[0002] Aviation lubricants provide lubrication, cooling, and impurity transport for various bearings and gears in aircraft engines. To ensure the safe, stable, and long-term operation of aircraft engines under high-temperature and high-speed conditions, the load-bearing capacity of lubricants is particularly critical. The load-bearing capacity test of lubricants is also a necessary inspection before the lubricants are approved for airworthiness and put into civil aviation use. To evaluate the load-bearing capacity of lubricants, it is necessary to test the lubricants under simulated actual aircraft engine operating conditions.
[0003] In the existing technology, the load-carrying capacity of lubricating oil under high speed and high load conditions is tested using the Ryder gear load-carrying capacity test method, but the test requires extremely high costs and time.
[0004] To address the aforementioned issues, the inventors explored alternative methods for testing the load-bearing capacity of lubricating oil. For instance, they improved existing standard FZG gear testing machines in terms of power and lubricating oil usage to create a high-speed FZG gear testing machine capable of high-speed gear testing (e.g., the high-speed gear load-bearing capacity testing machine disclosed in enterprise standard Q / 510107C.SD4001-2021, hereinafter referred to as the "high-speed FZG gear testing machine"). The reason for choosing the high-speed FZG gear testing machine is that its test gears have a gear ratio of 3:2, while the Ryder gear testing machine has a gear ratio of 1:1. However, the actual gear ratio in domestically produced aero-engine gearboxes better matches the gear ratio on the high-speed FZG gear testing machine. Therefore, based on this, the high-speed FZG gear testing machine can better and more accurately reproduce the actual operating conditions of domestically produced aero-engines.
[0005] During the test, the test was conducted on a high-speed FZG gear testing machine according to the operating conditions of the Ryder gear testing machine. The standard FZG gear testing machine is originally used for testing the lubricating oil load-bearing capacity under low-speed gears. When testing under low-speed gears, the standard FZG gear testing machine can select two different gear pairs: the standard FZG-A gear pair and the standard FZG-C gear pair. During the test, one of the gear pairs was selected on the testing machine according to the testing requirements of different aviation lubricating oils. During the test, the speed of the gear pair was about 1450 r / min, the test duration of each load level was 15 minutes of constant speed operation, the oil bath was 1.25L, the lubricating oil temperature was the ambient temperature under load level 5, and the oil temperature was controlled at 90℃ for load level 5 and above. Under this test method, the lubricating oil load-bearing capacity test level was 1-12.
[0006] Aviation lubricants mainly include helicopter gearbox lubricants and aviation turbine engine lubricants. When using the high-speed FZG gear testing machine for high-speed gear and high-load testing of aviation turbine engine lubricants, whether using standard FZG-A or standard FZG-C gear pairs, the operation is carried out according to the operating conditions of the Ryder gear testing machine: the gear pair speed reaches 10,000 r / min, the test duration for each load level is 10 minutes of constant speed operation, the oil temperature of the tested lubricant sprayed onto the gear is 74℃, and the lubrication flow rate is 1 L / min. However, using the standard FZG-A gear pair does not meet the SAE requirements. During the AS5780 test of aero-turbine engine lubricating oils, large-scale galling and failure occurred on the gear surface at level 4 (corresponding to a load of 70 Nm). This failure was due to two main reasons: firstly, the failure level was too low (theoretically, lubricating oil load capacity testing can reach 16 levels), making it impossible to accurately distinguish the load capacity of different aero-turbine engine lubricating oils; secondly, when the lubricating oil film ruptured leading to gear failure, the wear area on the tooth surface was prone to abrupt changes, generating instantaneous high temperatures and significant vibrations at the contact point between the two gears. This negatively impacted the high-speed FZG gear testing machine's frame, torque sensor, and loading clutch, significantly affecting its performance. The service life of the FZG gear testing machine is affected. When using the standard FZG-C gear pair to test the lubricating oil of aero-turbine engines that meets the requirements of SAEAS5780, although the tooth surface failure load level is increased to level 7 (corresponding to a load of 123 Nm), the change in tooth surface wear area from level 1 load to the level before failure is irregular. Moreover, the wear area is small before gear failure (usually less than 10%) until a large area of scuffing occurs on the gear surface, generating instantaneous high temperature. At this time, the wear area will suddenly increase to more than 80%. That is, the wear area of the tooth surface is prone to a large jump at failure, resulting in instantaneous high temperature and large vibration of the gear, which affects the service life of the test bench.
[0007] It is evident that the high-speed FZG gear testing machine, regardless of whether the standard FZG-A gear pair or the standard FZG-C gear pair is selected, cannot be used to evaluate the load-bearing capacity of aero-turbine engine lubricating oil under high speed and high load conditions. As a result, there is still no other method besides the Ryder gear load-bearing capacity test for testing the load-bearing capacity of aero-turbine engine lubricating oil under high gear speed and high load conditions. Summary of the Invention
[0008] The present invention aims to provide a gear pair for testing the load-carrying capacity of lubricating oil in aircraft turbine engines, in order to solve the problem that there is a lack of alternative methods in the prior art for testing the load-carrying capacity of lubricating oil in aircraft turbine engines, other than using Ryder gears on a Ryder gear testing machine.
[0009] To achieve the above objectives, the present invention adopts the following technical solution:
[0010] A gear pair for testing the lubricating oil load-carrying capacity of aircraft turbine engines includes an FZG-CR large gear and an FZG-CR small gear. The gear ratio of the FZG-CR large gear and the FZG-CR small gear is 3:2. The center distance between the FZG-CR large gear and the FZG-CR small gear during the load-carrying capacity test is 91.5 mm. The sum of the displacement coefficients of the FZG-CR large gear and the FZG-CR small gear is 0.34-0.36, and the displacement coefficient of the FZG-CR small gear is in the range of 0.15-0.27.
[0011] The principle and advantages of this scheme are as follows: This scheme improves the standard FZG-C gear pair used in high-speed FZG gear testing machines, specifically by improving the displacement coefficient of the gear pair. The improved gear pair includes an FZG-CR large gear and an FZG-CR small gear. The sum of the displacement coefficients of this improved gear pair is 0.34-0.36, and the displacement coefficient of the small gear ranges from 0.15-0.27. Under this modified gear pair, for those meeting SAE standards... When the AS5780 required aviation turbine engine lubricating oil was tested on the high-speed FZG gear testing machine under the operating conditions of the Ryder gear testing machine, the gear scuffing temperature was significantly increased, and the failure load was increased to level 9-11. At the same time, the wear area of the gear tooth surface increased almost linearly under different load levels. This allows this solution to accurately determine the lubricating oil's load-bearing capacity under a certain gear failure criterion. Moreover, unlike the standard FZG-C gear pair, the test does not need to be stopped only when a large area of the gear surface scuffs and instantaneous high temperature occurs, greatly reducing the impact on the life of the high-speed FZG gear testing machine.
[0012] This solution, through the improvement of the standard FZG-C gear pair, ensures that the load rating of the aviation turbine engine lubricating oil required by SAE AS5780 is not lower than level 9 when it reaches the maximum effective bonding temperature when applied to a high-speed FZG gear testing machine. The level 9 test load rating can basically meet the testing requirements of existing domestic aviation turbine engine lubricating oils. Therefore, this solution greatly reduces the cost of testing the load capacity of aviation lubricating oils and is conducive to promoting the production of domestic aviation turbine engine lubricating oils.
[0013] Preferably, as an improvement, when the displacement coefficient of the FZG-CR pinion is in the range of 0.177-0.27, when the FZG-CR large gear and FZG-CR pinion are tested on a high-speed FZG gear testing machine according to the operating conditions of the Ryder gear testing machine, the load at which the gear fails is 158Nm-193Nm.
[0014] Preferably, as an improvement, when the displacement coefficient of the FZG-CR pinion is in the range of 0.15-0.177, when the FZG-CR large gear and FZG-CR pinion are tested on a high-speed FZG gear testing machine according to the operating conditions of the Ryder gear testing machine, the load at which the gear fails is 193Nm-228Nm.
[0015] Preferably, as an improvement, the depth of the carburized layer on the tooth surface and the depth of the carburized layer at the root of the FZG-CR large gear and FZG-CR small gear are both 1.0-1.2 mm.
[0016] Preferably, as an improvement, the surface hardness of both the FZG-CR large gear and the FZG-CR small gear is 58-63 HRC, and the core hardness is 30-42 HRC.
[0017] Preferably, as an improvement, the pressure angle of both the FZG-CR large gear and the FZG-CR small gear is 20°. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the FZG-CR pinion structure in an embodiment of the present invention;
[0019] Figure 2 This is a schematic diagram of the structure of the FZG-CR large gear in an embodiment of the present invention;
[0020] Figure 3 This is a line graph showing the changes in the applied load and the scuffed area of the gear before gear failure during the test of test group 1.
[0021] Figure 4 This is a line graph showing the changes in the applied load and the scuffed area of the gear before gear failure during test group 2.
[0022] Figure 5 This is a line graph showing the changes in the applied load and the scuffed area of the gear before gear failure during test group 3. Detailed Implementation
[0023] The following detailed description illustrates the specific implementation method:
[0024] The basic implementation examples are as follows: Figures 1 to 5As shown, the gear pair used for testing the lubricating oil load-bearing capacity of aero-turbine engines includes an FZG-CR large gear and an FZG-CR small gear. The tooth ratio of the FZG-CR large gear and the FZG-CR small gear is 3:2. The center distance of the FZG-CR large gear and the FZG-CR small gear during the load-bearing capacity test on the high-speed FZG gear testing machine is 91.5 mm. In this embodiment, the large gear has 24 teeth, the small gear has 16 teeth, and the module is 4.5. The pressure angle of both gears is 20°. The sum of the displacement coefficients of the FZG-CR large gear and the FZG-CR small gear is 0.34-0.36, and the displacement coefficient of the FZG-CR small gear ranges from 0.15-0.27.
[0025] The surface hardness of both the FZG-CR large gear and FZG-CR small gear is 58-63 HRC, the core hardness is 33-42 HRC, and the depth of the carburized layer on the tooth surface and at the tooth root is 1.0-1.2 mm. Both the large gear and small gear are made of AISI 9310 aerospace material. The specific basic parameters of the gear pair in this embodiment are shown in Table 1 below.
[0026] Table 1. Basic Parameters of Gear Pairs Used for Lubricating Oil Load Capacity Testing in Aircraft Turbine Engines
[0027]
[0028] For the gear pairs used in the test of the lubricating oil load capacity of the aircraft turbine engine in Table 1 above, three sets of gear pairs were set up. Three pairs of gear pairs with the same parameters were produced in each set. The sum of the displacement coefficients of each pair of gear pairs was 0.3532. The displacement coefficients of all gear pairs are shown in Table 2. The correspondence between the load level, the applied load and the Ryder test method of the test in this embodiment is shown in Table 3 below (this correspondence has been disclosed in the existing standard).
[0029] Table 2. Gear pair parameters for testing the load-carrying capacity of lubricating oil in aero-turbine engines under different displacement coefficients.
[0030]
[0031] Table 3. Correspondence between Load Level and Load
[0032]
[0033] The three test groups, totaling nine pairs of gears, were placed in a high-speed FZG gear testing machine and tested according to the operating conditions of the Ryder gear testing machine. The test conditions included a pinion speed of 10,000 r / min, a constant speed operation time of 10 min for each load level, a lubricating oil temperature of 74℃ sprayed onto the gear, and a lubrication flow rate of 1 L / min.
[0034] The aviation turbine engine lubricating oil that meets the requirements of SAE AS5780 (Mobil Jet Oil II, which currently accounts for more than 55% of the global civil aviation market, was selected as the test reference oil) was used to test the gear pairs of test group 1, test group 2 and test group 3 respectively. The test results are shown in Table 4 below.
[0035] Table 4 Test data of gear pairs used for testing the load-carrying capacity of lubricating oil in aircraft turbine engines
[0036]
[0037] According to the data in Table 4 above, when the gear pair used in this embodiment for testing the load-bearing capacity of aero-turbine engine lubricating oil meets the requirements of SAE AS5780 and is tested on a high-speed FZG gear testing machine under the operating conditions of the Ryder gear testing machine, when the displacement coefficient of the FZG-CR pinion is 0.269 and the displacement coefficient of the FZG-CR gear is 0.0842, the load level at gear failure can reach level 9 or even level 10 when the gear pair of this test group 1 is tested on a high-speed FZG gear testing machine under the operating conditions of the Ryder gear testing machine. This ensures that when the aero-turbine engine lubricating oil is tested under the gear pair of this test group 1, at least a load level of level 8 can be tested without damaging the high-speed FZG testing machine.
[0038] When the displacement coefficient of the FZG-CR pinion is 0.177 and the displacement coefficient of the FZG-CR gear is 0.1762, when the gear pair of this test group 2 is tested on the high-speed FZG gear testing machine according to the operating conditions of the Ryder gear testing machine, the load level when the gear fails can reach level 11. This ensures that when the lubricating oil of the aircraft turbine engine is tested under the gear pair of this test group 2, the load level can be tested to at least level 10 without damaging the high-speed FZG testing machine.
[0039] When the displacement coefficient of the FZG-CR pinion is 0.151 and the displacement coefficient of the FZG-CR gear is 0.2022, when the gear pair of this test group 3 is tested on the high-speed FZG gear testing machine according to the operating conditions of the Ryder gear testing machine, the load level when the gear fails can reach level 12-13. This ensures that when the lubricating oil of the aviation turbine engine is tested under the gear pair of this test group 3, the load level can be tested to at least level 11 without damaging the high-speed FZG testing machine.
[0040] The above test data shows that the gear pair in this embodiment can achieve a tooth surface failure load level of 9-13, and nearly 90% of the test data can achieve a lubricating oil load capacity test of level 9 without damaging the high-speed FZG testing machine. Furthermore, under different load levels, the gear wear area basically increases linearly (combined with...). Figures 3 to 5 It can also easily find the lubricating oil's carrying capacity when the total wear area of the 16 tooth surfaces of the pinion accounts for 18% of the total effective contact area. Moreover, the test does not need to be stopped only when a large area of tooth surface adhesion and instantaneous high temperature occur, thus avoiding damage to the FZG gear testing machine.
[0041] As explained above, this embodiment, through improvements to the standard FZG-C gear pair, ensures that the load rating of the aviation turbine engine lubricating oil required by SAEAS 5780 at the maximum effective bonding temperature is not lower than level 9. A test load rating of level 9 basically meets the testing requirements of existing domestically produced lubricating oils. Therefore, this embodiment significantly reduces the cost of testing the load-bearing capacity of aviation lubricating oils, which is beneficial to promoting the production of domestic aviation turbine engine lubricating oils. Furthermore, as shown in Table 4 above, the maximum failure load difference in the parallel tests of the three pairs of gear pairs under the same test group does not exceed level 1, indicating high test repeatability. This demonstrates the high reliability of testing using the gear pair combined with the gear testing machine in this embodiment.
[0042] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.
Claims
1. A gear pair for testing the lubricating oil load-carrying capacity of an aircraft turbine engine, comprising an FZG-CR large gear and an FZG-CR small gear, wherein the gear ratio of the FZG-CR large gear and the FZG-CR small gear is 3:2, and the center distance between the FZG-CR large gear and the FZG-CR small gear during the load-carrying capacity test is 91.5 mm, characterized in that: The sum of the displacement coefficients of the FZG-CR large gear and the FZG-CR small gear is 0.34-0.36, of which the displacement coefficient of the FZG-CR small gear is in the range of 0.15-0.
27. The gear pair is used to test the lubricating oil of aero-turbine engines that meets the requirements of SAE AS5780 on a high-speed FZG gear testing machine. The test conditions include: the pinion speed reaches 10000 r / min, the test time for each load is 10 min of constant speed operation, the oil temperature of the lubricating oil sprayed onto the gear is 74℃, and the lubrication flow rate is 1 L / min. When the displacement coefficient of the FZG-CR pinion is in the range of 0.177-0.27, and the gear pair is tested under the test conditions, the load at which the gear fails is 158Nm-193Nm. When the displacement coefficient of the FZG-CR pinion is in the range of 0.15-0.177, and the gear pair is tested under the test conditions, the load at which the gear fails is 193Nm-228Nm.
2. The gear pair for testing the lubricating oil load-bearing capacity of an aircraft turbine engine according to any one of claims 1, characterized in that: The depth of the carburized layer on the tooth surface and the depth of the carburized layer at the root of the FZG-CR large gear and FZG-CR small gear are both 1.0-1.2 mm.
3. The gear pair for testing the lubricating oil load-carrying capacity of an aircraft turbine engine according to any one of claims 1-2, characterized in that: The surface hardness of both the FZG-CR large gear and the FZG-CR small gear is 58-63 HRC, and the core hardness is 30-42 HRC.
4. The gear pair for testing the lubricating oil load-bearing capacity of an aircraft turbine engine according to any one of claims 1-2, characterized in that: The pressure angles of both the FZG-CR large gear and the FZG-CR small gear are 20°.