Modular electric cylinder loading performance test bench and method for main reducer of small helicopter

Abstract

The application discloses a small helicopter main speed reducer modularization electric cylinder loading performance test bench and method, and the test bench comprises a cast iron platform, a rack, a driving motor, a first rotating speed and torque sensor, a diaphragm coupling, a first damping device and a rotor loading device; the rack is provided with a stand column, a cross beam and a detachable installation platform with adjustable height; the driving motor, a planetary reducer and a loading electric cylinder form a power electric closed loop.The application uses the installation platform to adapt to different models of measured main speed reducers, avoids rack cutting and welding transformation; through the coordinated output of radial and axial loads of multiple groups of servo electric cylinders, rotor bending moment and lift are reproduced, and the coupling defects of hydraulic loading channels are overcome; the damping structure is matched to inhibit the vibration impact of the transmission chain, power electric closed loop is used to realize energy recovery, and the technical defects of poor universality, loading coupling interference, easy damage of sensors by vibration and high test energy consumption of the existing test bench are solved.

Description

Technical Field

[0001] This invention belongs to the field of helicopter gearbox testing technology, specifically relating to a test bench and method for the loading performance of a modular electric cylinder of a small helicopter main gearbox. Background Technology

[0002] The main gearbox of a small helicopter is a core component of the helicopter's power transmission system. Its performance directly affects the overall flight safety and reliability of the aircraft. Performance testing is a crucial step in product development optimization and airworthiness certification, used to evaluate the reliability and service life of components under actual operating conditions. The performance of the test bench directly affects the accuracy of the test results. Most existing mature test benches are fixed welded frames with low modularity, high specialization, and poor versatility. They are only suitable for testing a single model, and changing test specimens requires cutting and welding modifications to the bench, resulting in long testing cycles and low equipment utilization. Rotor loads are mostly applied hydraulically, with response times down to the millisecond level, making it impossible to reproduce the millisecond-level dynamic loads during flight. The loading channel suffers from severe coupling interference, making it difficult to simultaneously and accurately simulate the combined conditions of rotor bending moment and lift. At the same time, the transmission link lacks a dedicated vibration damping structure, and vibration and shock can easily damage the speed-torque sensors. Most equipment does not adopt a closed-loop electrical power architecture, resulting in high testing energy consumption and high testing costs. Summary of the Invention

[0003] The purpose of this invention is to provide a test bench and method for loading performance of modular electric cylinders for the main reducer of a small helicopter, in order to solve the technical defects of existing test benches, such as fixed frame, poor modular versatility, large workload for replacing test specimens and modification; slow dynamic response of hydraulic loading, coupled loading channel, making it difficult to reproduce rotor bending moment and lift combined load; lack of vibration damping structure in the transmission link, which easily causes damage to speed and torque sensors, and high test energy consumption.

[0004] To achieve the above objectives, this application provides the following technical solution: The first aspect of this application provides a modular electric cylinder loading performance test bench for a small helicopter main gearbox, comprising: Cast iron platform; A frame is fixed on the cast iron platform. The frame includes columns, beams and mounting platforms. Each mounting platform is detachably connected to the column, and the mounting height of each mounting platform can be adjusted along the column. A drive motor is driven by a motor whose output end is connected to the input end of a first speed and torque sensor. The output end of the first speed and torque sensor is connected to the input end of a first damping device via a diaphragm coupling. The output end of the first damping device is used to drive the input end of an external main reducer under test. The rotor loading device includes multiple sets of servo electric cylinders, a support base, and a telescopic universal coupling. The multiple sets of servo electric cylinders are hinged to the mounting platform, and the output end of each servo electric cylinder is hinged to the support base. The lower end of the support base is used for assembly and connection with the rotor shaft of the external main reducer under test. The upper end of the support base is connected to the input end of the telescopic universal coupling. The output end of the telescopic universal coupling is driven by a second shock absorption device. The output end of the second shock absorption device is sequentially driven by a second speed and torque sensor, a planetary reducer, and a loading motor. Each of the servo electric cylinders is equipped with a force sensor, and multiple sets of servo electric cylinders can be driven to output radial and axial forces in a coordinated manner to reproduce the bending moment and lift load during rotor operation.

[0005] In one optional embodiment, the column is vertically positioned above the cast iron platform; The crossbeams are horizontally fixed between adjacent columns to form the main frame structure; The mounting platform includes a first mounting platform, a second mounting platform, a third mounting platform, and a fourth mounting platform; the first mounting platform is used to assemble a servo electric cylinder, the second mounting platform is used to assemble an axial loading electric cylinder, the third mounting platform is used to assemble a second shock absorption device, and the fourth mounting platform is used to assemble a planetary reducer and a loading motor.

[0006] In one optional embodiment, the plurality of said servo electric cylinders include: Two sets of radial force loading electric cylinders and two sets of axial force loading electric cylinders; The two sets of radial force loading electric cylinders are arranged horizontally to output radial force to simulate rotor bending moment; The two sets of axial force loading electric cylinders are arranged vertically to output axial force to simulate rotor lift.

[0007] In one alternative embodiment, one end of the force sensor is connected to the output end of the servo electric cylinder, and the other end of the force sensor is hinged to the load-bearing seat.

[0008] In one optional embodiment, both the first damping device and the second damping device are damping dampers; The first damping device is disposed between the diaphragm coupling and the input end of the external main reducer under test; The second shock absorption device is disposed between the telescopic universal coupling and the second speed and torque sensor; The first and second shock absorbers are used to isolate the vibration and impact generated by the operation of the main reducer.

[0009] In one optional embodiment, the drive motor, planetary reducer, and loading motor constitute a closed-loop power circuit. The drive motor operates in electric mode; The loading motor operates in power generation mode; The electrical energy generated by the loading motor is fed back to the power supply circuit of the drive motor to achieve a closed-loop power cycle.

[0010] In one optional embodiment, the column has a plurality of fourth mounting holes linearly and evenly distributed along its height direction; Each of the aforementioned mounting platforms is detachably locked to the fourth mounting holes at different height positions of the column via fasteners; Each of the aforementioned installation platforms can achieve adjustable installation height by using fourth installation holes of different heights.

[0011] In one optional embodiment, the load-bearing seat is provided with a double-eared hinged support; Each of the aforementioned servo electric cylinders is equipped with a pin at its output end; The output end of each servo electric cylinder is connected to the double-eared hinged support of the bearing seat via the pin to form a hinged pair.

[0012] In one alternative embodiment, the ends of each of the servo electric cylinders are hinged to the mounting platform; Each of the servo electric cylinders can swing relative to the mounting platform to adapt to changes in the spatial position of the load-bearing seat.

[0013] A second aspect of this application provides a method for testing the loading performance of a small helicopter main gearbox, the method employing the modular electric cylinder loading performance test bench for small helicopter main gearboxes as described above, comprising: According to the model and specifications of the main reducer under test, adjust the installation height of each mounting platform on the column to complete the assembly and alignment of each component of the test bench; Connect the input end of the main reducer under test to the first damping device, and assemble and fix the rotor shaft of the main reducer under test to the lower end of the bearing seat to complete the installation and positioning of the test piece. Start the drive motor, collect the input operating parameters through the first speed and torque sensor, and drive the tested main reducer to operate normally. The system controls multiple sets of servo electric cylinders to work together, and collects the applied load in real time through the force sensor, synchronously outputting radial and axial forces to reproduce the bending moment and lift load of the rotor operation. During operation, the first and second shock absorbers isolate the transmission link from vibration and impact, and the retractable universal coupling compensates for the axial displacement and radial coaxiality deviation of the transmission link. The power closed-loop circuit is used to realize the closed-loop circulation of electrical energy. At the same time, the second speed and torque sensor collects the operating parameters at the output end to complete the performance test and durability test of the main reducer under test.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The detachable and height-adjustable mounting platform on the test bench can accommodate the assembly requirements of different models of main reducers under test, avoiding the need for cutting and welding modifications to the test bench itself; by using multiple sets of servo electric cylinders to output radial and axial loads in coordination, the bending moment and lift loads of the rotor in actual operation can be reproduced, overcoming the drawbacks of hydraulic loading channel coupling; at the same time, the vibration damping structure of the transmission link is used to suppress vibration impact, and energy recovery is achieved through a power electrical closed loop, thereby solving the technical defects of existing test benches such as poor versatility, loading channel coupling interference, easy damage to sensors by vibration, and high test energy consumption.

[0015] 2. The main frame is formed by the fixed connection of columns and beams, and the test bench is divided into the first, second, third and fourth installation platforms. Each installation platform is equipped with a servo electric cylinder, axial loading electric cylinder, second shock absorption device, planetary reducer and loading motor respectively, which facilitates individual disassembly and maintenance. This solves the technical defects of traditional test benches with messy component layout and cumbersome debugging and disassembly operations.

[0016] 3. Two sets of horizontally arranged radial force loading electric cylinders output radial force to simulate rotor bending moment, and two sets of vertically arranged axial force loading electric cylinders output axial force to simulate rotor lift. The two types of electric cylinders work together to achieve load decoupling output, with fast dynamic response, and can reproduce rotor composite load conditions. This solves the technical defects of traditional hydraulic loading, such as slow dynamic response, coupled loading channels, and difficulty in accurately simulating the real rotor load.

[0017] 4. By connecting the two ends of the force sensor to the output end of the servo electric cylinder and the load-bearing seat respectively, the force sensor directly receives the load output, eliminating measurement interference caused by intermediate transmission gaps; the load acquisition path is short, effectively reducing measurement transmission errors, thereby solving the technical defects of insufficient test accuracy caused by the influence of the transmission structure in the load acquisition link.

[0018] 5. By setting damping shock absorbers as the first and second shock absorption devices in the transmission link, respectively arranged at the input end and the output transmission position, the vibration and shock generated by the operation of the main reducer are buffered and absorbed, and the vibration is isolated from being transmitted to the speed and torque sensor. This solves the technical defect of the existing test bench transmission link lacking a vibration reduction structure and the speed and torque sensor being easily damaged by vibration and shock.

[0019] 6. A closed-loop power circuit is formed by the drive motor, planetary reducer and loading motor. The loading motor is in the power generation mode and feeds the generated electrical energy back to the power supply circuit of the drive motor to realize the power closed loop cycle. The energy of the test process is recovered and reused, thereby solving the technical defects of traditional test benches that have no power recovery means, high test energy consumption and high test cost.

[0020] 7. By using several fourth mounting holes linearly and evenly distributed along the height direction of the column, the mounting platform can be locked with fasteners to achieve gear-type height adjustment of the mounting platform; positioning is achieved by using mounting holes, and the adjustment and positioning are reliable without the need to modify the platform body. This solves the technical defects of traditional platform height adjustment, such as cumbersome operation, poor positioning accuracy, and long test piece adaptation and debugging cycle.

[0021] 8. Through the double-eared hinged support set on the bearing seat, the output end of the servo electric cylinder forms a hinged pair with the double-eared hinged support by means of the pin; the double-eared hinged support releases multi-directional rotational freedom, eliminates the additional off-center load bending moment generated during the output process of the servo electric cylinder, and ensures the smooth transmission of loading force, thereby solving the technical defect of off-center load at the hinge position, which is prone to mechanism jamming.

[0022] 9. By hinged to the mounting platform at the end of the servo electric cylinder, the servo electric cylinder can generate a swing compensation amount relative to the mounting platform; by using the hinge swing to compensate for the position deviation during the assembly process, it can adapt to the spatial position change of the bearing seat, thereby solving the technical defects of the strict alignment requirements between the electric cylinder and the bearing seat and the easy assembly interference when clamping the test piece. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A three-dimensional sectional view of the loading performance test bench for the modular electric cylinder of the main reducer of a small helicopter provided by the present invention. Figure 2 Schematic diagram of the modular electric cylinder loading performance test bench for the main gearbox of a small helicopter provided by the present invention; Figure 3 A three-dimensional schematic diagram of the loading performance test bench for the modular electric cylinder of the main reducer of a small helicopter provided by the present invention. Figure 4 A schematic diagram of the central column of the modular electric cylinder loading performance test bench for the main reducer of a small helicopter provided by the present invention. Figure 5A schematic diagram of the first mounting platform in the modular electric cylinder loading performance test bench for the main reducer of a small helicopter provided by the present invention; Figure 6 A schematic diagram of the rotor loading device in the modular electric cylinder loading performance test bench for the main reducer of a small helicopter provided by the present invention. In the diagram: 1. Cast iron platform; 2. Frame; 21. Column; 211. First mounting hole; 212. Second mounting hole; 213. Third mounting hole; 214. Fourth mounting hole; 22. Crossbeam; 23. First mounting platform; 231. Fifth mounting hole; 232. Sixth mounting hole; 233. Seventh mounting hole; 24. Second mounting platform; 25. Third mounting platform; 26. Fourth mounting platform; 3. Drive motor; 4. First speed and torque sensor; 5. Diaphragm coupling; 6. First shock absorber; 7. Main reducer under test; 8. Rotor loading device; 81. First radial force loading electric cylinder; 82. First axial force loading electric cylinder; 83. Support seat; 84. Telescopic universal coupling; 85. Second radial force loading electric cylinder; 851. Force sensor; 852. Mounting support; 853. Servo motor; 86. Second axial force loading electric cylinder; 9. Second shock absorber; 10. Second speed and torque sensor; 11. Planetary reducer; 12. Loading motor. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0027] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0028] This embodiment provides a modular electric cylinder loading performance test bench and method for small helicopter main gearboxes, addressing the technical problems of existing helicopter main gearbox performance test benches, such as poor adaptability and compatibility, the need for cutting and welding modifications to the bench when replacing test specimens, long test cycles, and low equipment utilization; the common use of hydraulic loading for rotor loads, resulting in slow dynamic response, large coupling interference in the loading channel, and difficulty in reproducing millisecond-level dynamic rotor loads under real flight conditions; the lack of vibration damping and protection structures in the transmission link, making it easy for vibration and shock to damage the speed-torque sensors; and the high energy consumption and high testing costs of most test benches due to the lack of a closed-loop electrical power architecture. This test bench is designed for performance and durability testing of main gearboxes in 0.5-ton to 2-ton small helicopters, simulating torque, speed, rotor lift, and bending moment composite loads under real helicopter operating conditions, meeting the testing needs of product development optimization, performance verification, and airworthiness certification stages.

[0029] This modular electric cylinder loading performance test bench for small helicopter main gearboxes is a ground testing equipment for helicopter transmission components. It is mainly used for ground bench testing of the main gearboxes of small helicopters. Before the main gearbox 7 under test is installed on the aircraft, the test bench reproduces the comprehensive loads such as input torque, output torque, rotor lift, and rotor bending moment that the main gearbox bears during the actual flight of the helicopter. This is used to assess the load-bearing capacity, transmission efficiency, durability and reliability of the main gearbox 7 under test, and to complete the performance calibration and durability assessment.

[0030] During actual flight, helicopter rotors continuously generate alternating lift and bending moment loads. These loads are all transferred to the rotor output shaft of the main gearbox. The main gearbox needs to continuously withstand the combined effects of torque, axial lift, and radial bending moment. Traditional testing equipment can mostly only perform torque loading, making it difficult to simultaneously reproduce the complex force-torque coupling conditions at the rotor end. Some test benches that use hydraulic cylinders to achieve force loading are limited by the response characteristics of hydraulic valve groups, with dynamic responses mostly at the level of hundreds of milliseconds. They cannot simulate the rapidly fluctuating rotor loads at the millisecond level during flight. Furthermore, the loads between different loading cylinders are mutually coupled, making control and decoupling difficult and resulting in poor test reproduction.

[0031] This test bench uses a cast iron platform 1 as its base. The cast iron platform 1 has the characteristics of large mass, high rigidity, and strong resistance to vibration and deformation. It can absorb the vibration generated during the test, avoid displacement of the whole machine or deformation of the foundation, ensure the coaxial assembly accuracy between various transmission components, and provide a stable installation benchmark for the test bench 2, various transmission components, and loading components. The surface of the cast iron platform 1 is machined with standard T-slots, which can be used for fixing the feet of the test bench 2, and can also realize the quick positioning and locking of the auxiliary tooling of the main reducer 7 under test, and has good expansion and adaptation capabilities.

[0032] The present invention will now be described in further detail with reference to the accompanying drawings: like Figures 1-6 As shown, in a first aspect of the present invention, a modular electric cylinder loading performance test bench for a small helicopter main reducer is provided, comprising a cast iron platform 1; a frame 2, fixed on the cast iron platform 1, the frame 2 including a column 21, a crossbeam 22 and mounting platforms, each mounting platform being detachably connected to the column 21, and the mounting height of each mounting platform being adjustable along the column 21; a drive motor 3, the output end of which is connected to the input end of a first speed and torque sensor 4, the output end of the first speed and torque sensor 4 being connected to the input end of a first damping device 6 via a diaphragm coupling 5, the output end of the first damping device 6 being used for a drive connection to the input end of an external main reducer 7 under test; and a rotor loading device 8, including multiple sets of servo electric cylinders, The system includes a load-bearing base 83 and a retractable universal coupling 84; multiple servo cylinders are hinged to the mounting platform, with the output end of each servo cylinder hinged to the load-bearing base 83. The lower end of the load-bearing base 83 is used for assembly and connection with the rotor shaft of the external main reducer 7 under test, and the upper end of the load-bearing base 83 is connected to the input end of the retractable universal coupling 84. The output end of the retractable universal coupling 84 is connected to a second damping device 9, and the output end of the second damping device 9 is sequentially connected to a second speed and torque sensor 10, a planetary reducer 11, and a loading motor 12. Each servo cylinder is equipped with a force sensor 851, and the multiple servo cylinders can work together to output radial and axial forces to reproduce the bending moment and lift load during rotor operation.

[0033] In this embodiment, the test bench 2 is fixedly mounted on the cast iron platform 1. The test bench 2 includes columns 21, crossbeams 22, and multiple sets of mounting platforms. Each mounting platform is detachably connected to the columns 21, and the installation height of each mounting platform can be adjusted along the columns 21. The test bench 2 can flexibly adjust the spatial height position of each mounting platform according to the external dimensions and installation reference height of different models of main reducers 7 under test, without the need for cutting or welding modifications to the test bench body. This achieves compatible testing of multiple test specimens, shortens the pre-test setup and adjustment cycle, and improves the equipment's versatility. Existing traditional test benches are mostly integrally welded structures with fixed frame dimensions. When changing to different specifications of reducers under test, on-site flame cutting and welding are often required to modify the installation position. This not only results in a long debugging cycle, but welding thermal deformation can also damage the original shape and position accuracy of the test bench, requiring a lot of time for correction later. The modular and detachable test bench of this solution avoids such problems at the source.

[0034] The column 21 is vertically installed above the cast iron platform 1. The bottom of the column 21 has a first mounting hole 211 for fasteners to pass through, thereby locking the column 21 onto the cast iron platform 1. The side wall of the column 21 has a second mounting hole 212 and a third mounting hole 213. The crossbeam 22 is horizontally fixed between adjacent columns 21. The crossbeam 22 is bolted to the column 21 through the second mounting hole 212 and the third mounting hole 213. The crossbeam 22 and multiple columns 21 are interconnected to form the overall frame of the platform 2. The crossbeam 22 can constrain the spacing between the columns 21, significantly improving the overall rigidity and torsional stability of the entire platform 2 and suppressing the lateral displacement deformation of the columns 21 during loading operations.

[0035] When multiple servo electric cylinders output large radial loading forces, the column 21 will bear a large lateral thrust. The frame formed by the multi-layer crossbeams 22 can disperse the lateral load, prevent bending deformation of a single column, and ensure the geometric accuracy of the platform under long-term repeated loading conditions. Several fourth mounting holes 214 are linearly and evenly distributed along the height direction of the column 21. The fourth mounting holes 214 are equally spaced along the vertical direction of the column 21. Each mounting platform forms a detachable locking fit with the fourth mounting holes 214 at different height positions on the column 21 through fasteners. Each mounting platform can achieve gear-type adjustment of its own installation height by selecting the fourth mounting holes 214 at different height positions. The gear positioning is achieved by using prefabricated fourth mounting holes 214. Compared with the method of continuous adjustment using elongated holes, gear hole positioning has better shear resistance, will not slip when subjected to loading reaction force, has high assembly positioning consistency, and good reproducibility after multiple disassembly and assembly.

[0036] In this embodiment, the mounting platform specifically includes a first mounting platform 23, a second mounting platform 24, a third mounting platform 25, and a fourth mounting platform 26; the first mounting platform 23 is used to assemble servo electric cylinders, specifically a first radial force loading electric cylinder 81, a second radial force loading electric cylinder 85, and a bearing seat 83; the plate of the first mounting platform 23 is provided with a fifth mounting hole 231, a sixth mounting hole 232, and a seventh mounting hole 233.

[0037] The fifth mounting hole 231 cooperates with the fourth mounting hole 214 on the side of the column 21 to lock and fix the first mounting platform 23 on the column 21 and adjust the height level; the sixth mounting hole 232 is used to bolt to the mounting support 852 of the electric cylinder to complete the support fixation of the radial force loading electric cylinder; the seventh mounting hole 233 is used for the assembly limit of the bearing seat 83.

[0038] The second mounting platform 24 is used to assemble the axial loading electric cylinders, namely the first axial force loading electric cylinder 82 and the second axial force loading electric cylinder 86; the third mounting platform 25 is used to assemble the second shock absorption device 9; the fourth mounting platform 26 is used to assemble the planetary reducer 11 and the loading motor 12; wherein, when a certain component fails, only the component on the corresponding mounting platform needs to be disassembled, without disassembling the entire frame, which facilitates later maintenance and repair.

[0039] In this embodiment, the drive motor 3 is horizontally arranged and serves as the input power source for the test bench, supplying rotational power to the main reducer 7 under test to simulate the input speed and torque conditions of a helicopter engine. The drive motor 3 is a variable frequency servo motor, capable of stepless speed regulation over a wide speed range, covering various test speed conditions for small helicopter main reducers. The output of the drive motor 3 is connected to the input of the first speed and torque sensor 4, a precision testing device that collects real-time speed and torque operating parameters from the input of the main reducer 7 under test. The output of the first speed and torque sensor 4 is connected to the input of the first damping device 6 via a diaphragm coupling 5. The diaphragm coupling 5 can compensate for small-amplitude alignment deviations and transmit rotational torque. The diaphragm coupling 5 relies on the elastic deformation of a metal diaphragm to compensate for radial and angular deviations, but its axial compensation stroke is limited; therefore, in this design, it is only used as a small-deviation compensation component at the input. The output of the first damping device 6 is used for transmission docking with the input of the external main reducer 7 under test.

[0040] The rotor loading device 8 includes a first radial force loading cylinder 81, a first axial force loading cylinder 82, a bearing seat 83, a telescopic universal coupling 84, a second radial force loading cylinder 85, and a second axial force loading cylinder 86. The first radial force loading cylinder 81 and the second radial force loading cylinder 85 constitute two sets of radial force loading cylinders, which are arranged horizontally. The first axial force loading cylinder 82 and the second axial force loading cylinder 86 constitute two sets of axial force loading cylinders, which are arranged vertically.

[0041] Multiple sets of servo electric cylinders are hinged to the corresponding mounting platforms. The ends of each servo electric cylinder are hinged to the mounting platforms, and the servo electric cylinders can swing relative to the mounting platforms to adapt to the spatial position changes of the load-bearing seat 83, compensate for assembly alignment deviations, and reduce the risk of assembly interference when clamping the test piece.

[0042] In actual assembly operations, the machining and installation tooling of the main reducer 7 under test will have certain manufacturing and assembly errors. The hinged swing structure at both ends of the servo electric cylinder can release the degree of freedom of position and will not generate additional internal force inside the electric cylinder due to small assembly deviations, thus protecting the precision transmission parts such as lead screws and bearings inside the servo electric cylinder.

[0043] The load-bearing seat 83 is equipped with a double-eared hinged support, and each servo cylinder output end is equipped with a pin. The output end of each servo cylinder forms a hinge pair with the double-eared hinged support of the load-bearing seat 83 through the pin. The double-eared hinged support can release multiple degrees of rotational freedom, eliminate the additional eccentric bending moment generated during the output process of the servo cylinder, ensure that the load is stably and reliably transmitted to the load-bearing seat 83, and avoid the problems of eccentric load and mechanism jamming failure at the hinge position. If a single-eared hinge structure is used, the pin is more likely to bear a larger bending moment, and the wear of the pin and the hinge hole will be accelerated. The double-eared hinged support is subjected to symmetrical force, and the pin mainly bears the shear load, resulting in a longer service life of the hinge pair and more stable operation.

[0044] Each servo electric cylinder is equipped with a force sensor 851. One end of the force sensor 851 is connected to the output end of the servo electric cylinder, and the other end of the force sensor 851 is hinged to the load-bearing seat 83. The force sensor 851 directly collects the actual load output to the load-bearing seat 83, shortens the load acquisition and transmission path, eliminates measurement interference caused by intermediate transmission gaps, and improves the load test accuracy.

[0045] The force sensor 851 adopts a hinged installation method to avoid the interference of bending moment on the force sensor measurement results, ensuring that the force sensor only collects axial tensile and compressive signals, thus improving the accuracy of force value acquisition. The servo electric cylinder is driven by the servo motor 853, and the electrical signal directly drives and controls it, with a response time of millisecond level. Two sets of horizontally arranged radial force loading electric cylinders output radial force to simulate the bending moment generated by the rotor operation; two sets of vertically arranged axial force loading electric cylinders output axial force to simulate the lift generated by the rotor operation. Multiple sets of servo electric cylinders work together to synchronously output radial and axial forces, reproducing the combined load conditions of bending moment and lift during rotor operation. The electric cylinder loading realizes closed-loop control of force and displacement, and decouples the load output, overcoming the defects of coupling and dynamic response lag in traditional hydraulic loading channels. It can reproduce complex and varied rotor load curves and meet the test requirements of dynamic load simulation.

[0046] The lower end of the bearing seat 83 is used to assemble and connect with the rotor shaft of the external main reducer 7 under test, and the upper end of the bearing seat 83 is connected to the input end of the telescopic universal coupling 84. The telescopic universal coupling 84 can not only compensate for the radial coaxiality deviation of the transmission link, but also compensate for the axial displacement deviation caused by the change of rotor load lift, thus making up for the shortcomings of the traditional diaphragm coupling in terms of insufficient axial compensation capability.

[0047] During the test, when the axial loading electric cylinder applies varying lift, the rotor shaft will experience slight axial movement. The sliding spline pair inside the telescopic universal coupling 84 can absorb this axial displacement, preventing the axial force from being transmitted to the rear-end second speed and torque sensor 10 and avoiding damage to the sensor. The output end of the telescopic universal coupling 84 is connected to the second damping device 9; the output end of the second damping device 9 is sequentially connected to the second speed and torque sensor 10, the planetary reducer 11, and the loading motor 12. The planetary reducer 11 serves as a test gearbox, completing the speed and torque matching conversion; the loading motor 12 serves as the load actuation component.

[0048] Both the first damping device 6 and the second damping device 9 are damping shock absorbers. The first damping device 6 is arranged between the diaphragm coupling 5 and the input end of the external main reducer 7 under test. The second damping device 9 is arranged between the telescopic universal coupling 84 and the second speed and torque sensor 10. The first damping device 6 and the second damping device 9 are used together to isolate the vibration and impact generated during the operation of the main reducer 7 under test, and to block the vibration from being transmitted to the first speed and torque sensor 4 and the second speed and torque sensor 10, thus providing effective protection for the precision sensing components and preventing the sensors from being damaged or malfunctioning due to vibration and impact.

[0049] When the main reducer 7 under test is running, the gear meshing will generate continuous vibration and impact. This vibration is transmitted to both ends along the transmission link. The grating and strain gauge elements inside the speed and torque sensor are very sensitive to vibration. Strong vibration can easily cause measurement drift or even damage to the device. The front and rear damping shock absorbers can consume vibration energy, attenuate vibration amplitude, and ensure long-term reliable operation of the sensor.

[0050] The drive motor 3, planetary reducer 11, and loading motor 12 work together to form a closed power circuit. The drive motor 3 operates in electric mode and outputs rotational power to drive the tested main reducer 7. The loading motor 12 operates in generator mode and applies torque load to the transmission system. The electrical energy generated by the loading motor 12 is fed back to the power supply circuit of the drive motor 3, thereby realizing a closed power cycle.

[0051] The power-electrically closed loop can convert the mechanical energy of the test process into electrical energy for recycling and reuse, significantly reducing the power consumption during the test process and lowering the electricity cost of long-term durability tests. When conducting durability tests of hundreds or thousands of hours, if an energy-consuming load is used, all the power will be dissipated as heat, resulting in huge power consumption. This power-electrically closed architecture feeds back and reuses most of the electrical energy, requiring only a small portion of the electrical energy to compensate for the mechanical and electrical losses of the system, resulting in significant energy savings.

[0052] The first speed and torque sensor 4 collects the input speed and torque, and the second speed and torque sensor 10 collects the output speed and torque. By using the measured data from the two sets of sensors, the actual transmission ratio and transmission efficiency of the main reducer 7 under test can be calculated, and the test and evaluation of multiple performance indicators of the main reducer can be completed.

[0053] During operation, the drive motor 3 works as a power source in electric mode, outputting rotational power, which is transmitted to the input end of the main reducer 7 under test via the first speed and torque sensor 4, diaphragm coupling 5, and first damping device 6, simulating the speed and torque output of a helicopter engine; the first speed and torque sensor 4 collects the speed and torque signals at the input end in real time, providing raw test data for closed-loop control and performance calculation under operating conditions.

[0054] Two sets of horizontally arranged radial force loading electric cylinders and two sets of vertically arranged axial force loading electric cylinders together constitute a multi-dimensional loading unit. The servo motor 853 drives the servo electric cylinders to perform telescopic movements, and the force sensor 851 directly collects and outputs the actual load to the bearing seat 83. Both ends of the servo electric cylinder adopt a hinged structure, which can not only release the additional internal force caused by assembly deviation, but also coordinate the output of radial force and axial force, synthesize the bending moment and lift of the rotor in actual operation on the bearing seat 83, and reproduce the combined force and torque load on the rotor bearing. The bearing seat 83 transmits the torque to the rear end through the telescopic universal coupling 84. The telescopic universal coupling 84 absorbs the radial coaxial deviation and axial displacement generated during the test process, and eliminates the additional transmission stress caused by insufficient compensation.

[0055] The torque is sequentially input to the planetary reducer 11 through the second damping device 9 and the second speed and torque sensor 10 for speed matching, and finally transmitted to the loading motor 12. The loading motor 12 operates in the power generation mode, applying a reverse torque load to the entire transmission system to simulate the output resistance of the main reducer. The electrical energy generated by the loading motor 12 is fed back to the power supply circuit of the drive motor 3, forming a closed power circuit. Most of the mechanical energy is recycled and reused in the form of electrical energy, only compensating for the mechanical and electrical losses of the system, and greatly reducing the energy consumption of long-term durability tests.

[0056] The first damping device 6 and the second damping device 9 on the output side are respectively arranged in the front and rear transmission links of the main reducer 7 under test. They attenuate the vibration and impact caused by gear meshing and alternating loads, and block the transmission of vibration to the first speed and torque sensor 4 and the second speed and torque sensor 10, thus protecting the precision sensing elements. The second speed and torque sensor 10 collects the speed and torque parameters at the output end, and combines them with the data collected at the input end to calculate the actual transmission ratio, transmission efficiency and other performance indicators of the main reducer 7 under test, thereby completing the performance test and durability assessment of the main reducer.

[0057] The entire test bench is controlled by an external measurement and control system. On the one hand, it adjusts the speed of the drive motor 3 and the load torque of the loading motor 12. On the other hand, it performs force-displacement closed-loop control on multiple sets of servo electric cylinders, which can realize the output of constant load and alternating load spectrum. This simulates different flight conditions such as helicopter hovering, take-off, and maneuvering, and completes the performance calibration and durability verification of the main reducer of small helicopters in the 0.5-ton to 2-ton class.

[0058] In a second aspect, this invention provides a method for testing the loading performance of a small helicopter main reducer. This method utilizes the aforementioned modular electric cylinder loading performance test bench for small helicopter main reducers. The method includes: First, based on the model and specifications of the main reducer 7 under test, referring to the drawings of the tested component, determining the height of the input end and the rotor shaft installation height of the main reducer 7, thereby determining the target installation height of each mounting platform. Adjusting the installation height of each mounting platform on the column 21, and locking each mounting platform to the fourth mounting holes 214 at different heights on the column 21 using fasteners, completes the assembly and alignment of all components of the test bench, adapting to the installation reference dimensions of the main reducer 7 under test. After the height adjustment is completed, it is necessary to verify the coaxiality between each transmission component to ensure that the transmission alignment meets the assembly technical requirements.

[0059] Next, the input end of the main reducer 7 under test is connected to the first damping device 6, and the rotor shaft of the main reducer 7 under test is assembled and fixed to the lower end of the bearing seat 83 to complete the installation and positioning of the test piece. During the assembly process, the servo electric cylinder can swing relative to the mounting platform to compensate for the assembly position deviation and eliminate clamping interference. After the mechanical connection is completed, check that all hinge pins are assembled in place, tighten all fasteners according to the specified torque, confirm that the signal lines of the force sensor 851 and the speed and torque sensor are firmly connected, and complete the zero-point calibration of the sensors.

[0060] Next, start the drive motor 3. The drive motor 3 outputs power to drive the main reducer 7 under test to run. The drive motor adjusts the speed according to the speed curve set in the test outline. The speed and torque operating parameters at the input end are collected in real time by the first speed and torque sensor 4 so that the main reducer 7 under test reaches the set test speed condition. After the speed operating state is stable, the loading process is then entered.

[0061] Then, multiple sets of servo electric cylinders are controlled to work in coordination. The applied load is collected in real time by force sensor 851. Two sets of radial force loading electric cylinders output radial force to simulate rotor bending moment, and two sets of axial force loading electric cylinders output axial force to simulate rotor lift. The radial and axial forces are output synchronously to reproduce the combined load of bending moment and lift during rotor operation. It can output constant static load or alternating dynamic load according to a preset load spectrum to simulate rotor load changes under different operating conditions such as helicopter takeoff, hovering, and maneuvering flight.

[0062] During equipment operation, the first shock absorber 6 and the second shock absorber 9 isolate the vibration and impact of the transmission link, protecting the front and rear speed and torque sensors. At the same time, the retractable universal coupling 84 compensates for the axial displacement and radial coaxiality deviation of the transmission chain, avoiding damage to the transmission components caused by misalignment. The measurement and control system collects various data from the force sensor and speed and torque sensor in real time, and monitors vibration, load, and speed parameters in real time. Once the parameters exceed the limits, the system triggers the protection logic, unloads and stops the machine in time, and ensures the safety of the test equipment and the test specimen.

[0063] A closed-loop power circuit is used to achieve closed-loop energy circulation and recover test energy. Simultaneously, the second speed and torque sensor 10 collects the output speed and torque operating parameters. Combined with the data collected at the input end, the transmission ratio, transmission efficiency, and other indicators of the tested main reducer 7 are calculated to complete the performance test and long-term durability test of the tested main reducer 7. During the durability test, the speed-load spectrum is executed cyclically according to the test outline, various performance parameters are recorded at stages, the operating status of the main reducer is observed, and the durability assessment is completed.

[0064] During the assembly and debugging of this test bench, multiple columns 21 are first secured to the cast iron platform 1 using bolts from the first mounting holes 211. During the assembly of the columns, a level is used to calibrate the verticality of the columns 21 to ensure that the multiple columns are parallel to each other and to avoid uneven stress during the later assembly of the platform.

[0065] Subsequently, the crossbeam 22 is assembled, and the crossbeam 22 is locked to the column 21 through the second mounting hole 212 and the third mounting hole 213 to build the overall frame of the platform 2. After the multi-layer crossbeam 22 is assembled in sequence, the overall geometric tolerance of the frame is checked again. Then, according to the external dimensions of the main reducer 7 under test, the fourth mounting hole 214 at a suitable height on the column 21 is selected, and the first mounting platform 23, the second mounting platform 24, the third mounting platform 25, and the fourth mounting platform 26 are assembled in sequence to complete the gear-type height adjustment of each mounting platform.

[0066] The first mounting platform 23 is locked to the column 21 via the fifth mounting hole 231. The sixth mounting hole 232 is used to assemble the mounting bracket 852 corresponding to the electric cylinder, and the seventh mounting hole 233 is used to assemble the load-bearing seat 83. The first radial force loading electric cylinder 81 and the second radial force loading electric cylinder 85 are assembled to the first mounting platform 23. The first axial force loading electric cylinder 82 and the second axial force loading electric cylinder 86 are assembled to the second mounting platform 24. The second shock absorption device 9 is assembled to the third mounting platform 25. The planetary reducer 11 and the loading motor 12 are assembled to the fourth mounting platform 26. The cylinder body end of the servo electric cylinder is hinged to the corresponding mounting platform. The output end of the servo electric cylinder is assembled to the double-eared hinged bracket on the load-bearing seat 83 via a pin to form a hinge pair. The force sensor 851 is assembled between the output end of the servo electric cylinder and the load-bearing seat 83. After the hinge pin is assembled, it is confirmed that the hinge pair rotates flexibly without any jamming.

[0067] The output end of the drive motor 3 is connected to the first speed and torque sensor 4, the output end of the first speed and torque sensor 4 is connected to the diaphragm coupling 5, the diaphragm coupling 5 is connected to the first damping device 6, and the first damping device 6 has a reserved docking interface for connecting the input shaft of the main reducer 7 under test.

[0068] When assembling the coupling, align it according to the centering requirements to reduce angular and radial installation deviations and lower operating vibrations. For the output rotor side transmission link assembly: connect the upper end of the bearing seat 83 to the retractable universal coupling 84, which in turn connects to the second damping device 9, the second speed and torque sensor 10, the planetary reducer 11, and the loading motor 12. After completing the mechanical assembly, complete the electrical wiring to construct an electrical feedback circuit with a closed power circuit. Connect each force sensor 851, the first speed and torque sensor 4, and the second speed and torque sensor 10 to the measurement and control system. After all hardware wiring is completed, conduct no-load testing of the equipment. Run the drive motor 3, the loading motor 12, and each set of servo cylinders in sequence to check whether the actions of each mechanism are normal and whether the sensor signal acquisition is stable. Eliminate potential faults caused by assembly. Only after the no-load testing is qualified can the main reducer 7 under test be installed for formal testing.

[0069] During the test, the drive motor 3 is in electric mode, outputting power to drive the tested main reducer 7 to rotate, simulating the engine input mode; the load motor 12 is in generator mode, providing torque load, and the electrical energy is fed back to the power supply circuit of the drive motor 3 to realize power recovery.

[0070] In the rotor loading device 8, the horizontally arranged first radial force loading electric cylinder 81 and second radial force loading electric cylinder 85 output radial force to apply to the bearing seat 83, replicating the rotor bending moment; the vertically arranged first axial force loading electric cylinder 82 and second axial force loading electric cylinder 86 output axial force to apply to the bearing seat 83, replicating the rotor lift; the force sensor 851 provides real-time feedback on the actual loading force, realizing closed-loop force control. The telescopic universal coupling 84 absorbs the axial displacement and radial alignment deviation caused by rotor loading; the first damping device 6 and the second damping device 9 absorb the vibration and impact generated by the reducer operation, protecting the precision test sensor.

[0071] The first speed and torque sensor 4 and the second speed and torque sensor 10 respectively collect the speed and torque parameters at the input and output ends to complete the calculation of the main reducer performance parameters. This allows for both short-term performance baseline tests and durability assessment tests lasting thousands of hours. During long-term durability tests, the power closed-loop circuit continuously plays an energy recovery role, significantly reducing the overall power consumption of the machine. At the same time, the two-stage damping and vibration reduction device continuously attenuates the vibration caused by gear meshing, effectively protecting the high-value speed and torque sensors and reducing the risk of damage to the test equipment.

[0072] This invention utilizes multiple sets of fourth mounting holes 214 on the column 21 to achieve gear-type height adjustment of each mounting platform. For different models of small helicopter main reducer test pieces, there is no need to cut, weld, or modify the test stand body. Assembly and adaptation can be completed by directly adjusting the height of the mounting platform. The equipment has strong versatility, short test piece replacement and debugging cycle, and high equipment utilization rate.

[0073] A servo electric cylinder is used as the loading actuator. The servo motor 853 drives the electric cylinder to output the load, providing millisecond-level dynamic response. The radial and axial loads are decoupled, which can accurately reproduce the complex changes in lift and bending moment generated by the rotor during helicopter flight, overcoming the shortcomings of slow response and channel coupling in traditional hydraulic loading. The transmission link is equipped with both a diaphragm coupling 5 and a telescopic universal coupling 84 to accommodate radial and axial displacement compensation. At the same time, two damping shock absorbers, the first damping device 6 and the second damping device 9, are arranged in series to isolate vibration and shock, providing double protection for the speed and torque sensors and preventing damage to expensive sensing components caused by vibration and alignment deviation.

[0074] The test bench is equipped with a closed-loop power circuit, with the load motor 12 generating power to feed back energy. This significantly reduces the overall energy consumption and saves on testing costs during long-term durability tests. Hinged structures are used between the servo cylinder and the mounting platform, and between the servo cylinder output and the load-bearing seat 83. Both ends of the cylinder can achieve swing compensation, reducing the difficulty of specimen clamping and alignment, and eliminating the risk of assembly interference. The load-bearing seat 83 adopts a double-ear hinged support structure to avoid additional bending moments at the hinge positions, ensuring effective load transfer.

[0075] It should be noted that this application is not limited to the implementation methods described in this embodiment. The embodiments listed above are only illustrative examples. Within the scope of the complete technical concept of this application, various equivalent modifications can be made to this application.

[0076] For example, the number of servo electric cylinders can be adjusted according to the load level of the main reducer under test; the spacing of the fourth mounting holes 214 can be adjusted according to the accuracy requirements of the test bench; damping shock absorbers can be selected from products with different damping coefficients; the electrical topology of the power electric closed loop can adopt other equivalent feedback topologies in the industry; the telescopic universal coupling 84 can be selected from other equivalent compensation coupling structures; the thickness and weight of the cast iron platform can be adjusted according to the load level.

[0077] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A test bench for the loading performance of a modular electric cylinder in a small helicopter main gearbox, characterized in that, include: Cast iron platform; A frame is fixed on the cast iron platform. The frame includes columns, beams and mounting platforms. Each mounting platform is detachably connected to the column, and the mounting height of each mounting platform can be adjusted along the column. A drive motor is driven by a motor whose output end is connected to the input end of a first speed and torque sensor. The output end of the first speed and torque sensor is connected to the input end of a first damping device via a diaphragm coupling. The output end of the first damping device is used to drive the input end of an external main reducer under test. The rotor loading device includes multiple sets of servo electric cylinders, a support base, and a telescopic universal coupling. The multiple sets of servo electric cylinders are hinged to the mounting platform, and the output end of each servo electric cylinder is hinged to the support base. The lower end of the support base is used for assembly and connection with the rotor shaft of the external main reducer under test. The upper end of the support base is connected to the input end of the telescopic universal coupling. The output end of the telescopic universal coupling is driven by a second shock absorption device. The output end of the second shock absorption device is sequentially driven by a second speed and torque sensor, a planetary reducer, and a loading motor. Each of the servo electric cylinders is equipped with a force sensor, and multiple sets of servo electric cylinders can be driven to output radial and axial forces in a coordinated manner to reproduce the bending moment and lift load during rotor operation.

2. The modular electric cylinder loading performance test bench for the main gearbox of a small helicopter according to claim 1, characterized in that, The column is vertically positioned above the cast iron platform; The crossbeams are horizontally fixed between adjacent columns to form the main frame structure; The mounting platform includes a first mounting platform, a second mounting platform, a third mounting platform, and a fourth mounting platform; the first mounting platform is used to assemble a servo electric cylinder, the second mounting platform is used to assemble an axial loading electric cylinder, the third mounting platform is used to assemble a second shock absorption device, and the fourth mounting platform is used to assemble a planetary reducer and a loading motor.

3. The modular electric cylinder loading performance test bench for the main gearbox of a small helicopter according to claim 1, characterized in that, The multiple sets of the servo electric cylinders include: Two sets of radial force loading electric cylinders and two sets of axial force loading electric cylinders; The two sets of radial force loading electric cylinders are arranged horizontally to output radial force to simulate rotor bending moment; The two sets of axial force loading electric cylinders are arranged vertically to output axial force to simulate rotor lift.

4. The modular electric cylinder loading performance test bench for the main gearbox of a small helicopter according to claim 1, characterized in that, One end of the force sensor is connected to the output end of the servo electric cylinder, and the other end of the force sensor is hinged to the bearing seat.

5. The modular electric cylinder loading performance test bench for the main gearbox of a small helicopter according to claim 1, characterized in that, Both the first and second damping devices are damping shock absorbers; The first damping device is disposed between the diaphragm coupling and the input end of the external main reducer under test; The second shock absorption device is disposed between the telescopic universal coupling and the second speed and torque sensor; The first and second shock absorbers are used to isolate the vibration and impact generated by the operation of the main reducer.

6. The modular electric cylinder loading performance test bench for the main gearbox of a small helicopter according to claim 1, characterized in that, The drive motor, planetary reducer, and loading motor constitute a closed-loop power circuit. The drive motor operates in electric mode; The loading motor operates in power generation mode; The electrical energy generated by the loading motor is fed back to the power supply circuit of the drive motor to achieve a closed-loop power cycle.

7. The modular electric cylinder loading performance test bench for the main gearbox of a small helicopter according to claim 2, characterized in that, The column has several fourth mounting holes evenly distributed linearly along its height direction. Each of the aforementioned mounting platforms is detachably locked to the fourth mounting holes at different height positions of the column via fasteners; Each of the aforementioned installation platforms can achieve adjustable installation height by using fourth installation holes of different heights.

8. The modular electric cylinder loading performance test bench for the main gearbox of a small helicopter according to claim 1, characterized in that, The load-bearing seat is provided with a double-eared hinged support; Each of the aforementioned servo electric cylinders is equipped with a pin at its output end; The output end of each servo electric cylinder is connected to the double-eared hinged support of the bearing seat via the pin to form a hinged pair.

9. The modular electric cylinder loading performance test bench for the main gearbox of a small helicopter according to claim 1, characterized in that, The ends of each of the servo electric cylinders are hinged to the mounting platform; Each of the servo electric cylinders can swing relative to the mounting platform to adapt to changes in the spatial position of the load-bearing seat.

10. A method for testing the loading performance of a small helicopter main gearbox, characterized in that, The method is performed using the modular electric cylinder loading performance test bench for the small helicopter main gearbox as described in any one of claims 1-9, including: S1. According to the model and specifications of the main reducer under test, adjust the installation height of each mounting platform on the column to complete the assembly and alignment of each component of the test bench; S2. Connect the input end of the main reducer under test to the first damping device, and assemble and fix the rotor shaft of the main reducer under test to the lower end of the bearing seat to complete the installation and positioning of the test piece. S3. Start the drive motor, collect the input operating parameters through the first speed and torque sensor, and drive the tested main reducer to operate normally. S4. Control the coordinated action of multiple sets of servo electric cylinders, collect the applied load in real time through the force sensor, and synchronously output radial force and axial force to reproduce the bending moment and lift load of the rotor operation. S5. During operation, the first and second shock absorbers isolate the vibration and impact of the transmission link, and the retractable universal coupling compensates for the axial displacement and radial coaxiality deviation of the transmission link. S6. The power closed-loop circuit is used to realize the closed-loop circulation of electrical energy. At the same time, the output terminal operating parameters are collected through the second speed and torque sensor to complete the performance test and durability test of the main reducer under test.

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