Face gear planetary transmission system dynamic uniform load test platform and test method

Abstract

The invention discloses a face gear planetary transmission system dynamic uniform load test platform and test method, and belongs to the field of gear transmission, and the test platform comprises a rack, a drive motor, a step-up gear box, a face gear planetary transmission system, a magnetic powder brake, a torque sensor, a slip ring, a stress strain test system and the like. The face gear planetary transmission system comprises an input face gear, a planet wheel, a planet carrier, a fixed face gear and the like. According to the dynamic uniform load test, stress values at the tooth root of the face gear and the tooth root of the planetary gear are measured mainly through strain gauges, and the corresponding relation between the tooth root stress and the meshing force at the gear meshing point is obtained through finite element simulation. And calculating the dynamic uniform load coefficient according to the dynamic meshing force root-mean-square values and the average values obtained at the tooth roots of the face gear and the planetary gear. By testing and analyzing the dynamic uniform load coefficient, the load distribution characteristic of the face gear planetary transmission system can be accurately revealed, a scientific basis is provided for structural parameter optimization, meshing performance improvement and reliability design of the face gear planetary transmission system, and then accurate and high-performance design of the transmission system is achieved.

Description

Technical Field

[0001] This invention belongs to the field of gear transmission, and specifically relates to a dynamic load-sharing test platform and test method for a face gear planetary transmission system, which is used for transmission system optimization design. Background Technology

[0002] As high-end equipment upgrades towards higher power density and wider speed ranges, planetary transmissions have become the preferred solution in core fields such as automotive automatic transmissions, wind power speed increasers, robot joints, and aero-engine reducers due to their compact structure and power distribution characteristics. Face gear planetary transmissions, as a new derivative structure of planetary transmissions, seamlessly adapt to all application scenarios of traditional planetary transmissions thanks to their unique shaft angle meshing characteristics and optimized tooth profile design. Compared to traditional cylindrical gear planetary transmissions, face gear planetary transmissions have significant performance advantages: face gear transmissions have higher overlap ratios and stronger load-bearing capacity; moreover, the transmission ratio adjustment is not limited by planetary gear parameters, and a wide range of speed changes can be achieved through face gear tooth combinations, making them more suitable for frequent gear shifting in automotive transmissions and multi-condition switching in construction machinery and other transmission scenarios.

[0003] Dynamic load sharing characteristics are a core indicator determining the reliability of planetary transmissions. Uneven load distribution on the tooth surface leads to stress concentration on individual teeth, shortening the system's lifespan. Especially in face gear planetary transmissions, the coupling effect of manufacturing errors, installation clearances, and elastic deformation exacerbates dynamic load fluctuations, necessitating precise testing to obtain the dynamic load sharing coefficient to guide structural optimization. However, current research largely focuses on theoretical modeling of traditional planetary transmissions, and a dedicated dynamic load sharing testing platform for face gear planetary transmissions remains lacking, along with experimental methods to quantify their load distribution patterns. This lack of testing technology severely restricts the engineering application of face gear planetary transmissions in high-end equipment; therefore, there is an urgent need to construct a dynamic load sharing testing platform and method for face gear planetary transmission systems.

[0004] In the prior art, Chinese patent application number CN202510336873.8 discloses a convenient, practical, and high-precision method for measuring the load sharing and dynamic load coefficient of a planetary transmission system; Chinese patent application number CN202210752032.1 discloses a method for determining the tooth root stress and load sharing coefficient of a planetary gear train; and Chinese patent application number CN202011567404.0 discloses a system for testing the load unevenness coefficient of a planetary gear transmission. However, all of these related technologies involve surface gear planetary transmissions, and the dynamic load sharing test only targets either the sun gear or the planet gears, without comparing and analyzing the two. Summary of the Invention

[0005] Purpose of the invention: Addressing the lack of a dedicated dynamic load sharing test platform and experimental method for face gear planetary transmissions, which hinders the accurate acquisition of their dynamic load sharing coefficient and restricts their engineering applications, this invention aims to construct a dynamic load sharing test platform and method for face gear planetary transmission systems. This will clarify the impact of manufacturing errors, installation clearances, and elastic deformation on the system load distribution, accurately quantify the dynamic load sharing characteristics, provide experimental support for the structural optimization of face gear planetary transmissions, break through the bottleneck of testing technology, and promote their engineering application in high-end equipment.

[0006] Technical solution: To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0007] A dynamic load-sharing test platform and test method for a face gear planetary transmission system is characterized in that the test platform includes a frame, a drive motor, a speed-increasing gearbox, a face gear planetary transmission system, a magnetic powder brake, a torque sensor, a slip ring, a stress-strain test system, etc.

[0008] The drive motor is mounted on the frame. The output shaft of the drive motor is connected to one end of a torque sensor, and the other end of the torque sensor is connected to the large gear shaft of the speed-increasing gearbox. The large gear meshes with the small gear for speed-increasing transmission. The small gear shaft of the speed-increasing gearbox is hollow. One end of the small gear shaft is connected to the input face gear shaft of the planetary gear transmission system via a hollow splined shaft, and the other end is connected to a slip ring. The slip ring is connected to a stress-strain signal acquisition instrument. n sets of strain gauges are arranged circumferentially at the root of the input face gear, where n is the number of planetary gears. The strain gauge wiring is output to the slip ring via the central control shaft of the small gear.

[0009] Optionally, the speed-increasing gearbox may employ spur gears, helical gears, or herringbone gears in a single-stage meshing transmission.

[0010] The face gear planetary transmission system includes two face gears (left and right), n planet gears, and a planet carrier. Power is input through the left face gear and output through the planet carrier. The planet carrier is connected to a torque sensor, which is further connected to a magnetic powder brake.

[0011] Optional: The left and right face gears can be spur gears, helical gears, or herringbone face gears.

[0012] Optionally, the power input is via face gear and output is via planetary carrier, which can be replaced by the power input being via planetary carrier and output being via face gear.

[0013] An offline stress-strain signal acquisition system is installed on the root of each of the n planetary gear teeth to read the data after the test is completed.

[0014] Optional: The offline strain gauge can be attached to the tooth surface at the tooth root or to the tooth root end face, and the attachment position is determined by the 30° critical section method.

[0015] The dynamic load-averaging test mainly involves measuring the stress value F at the root of the gear teeth using strain gauges. f1 The stress value F at the root of the planetary gear teeth f2 The stress value can be collected from the tooth surface of a face gear or a cylindrical gear, or from the tooth root end face.

[0016] The obtained data is filtered, and then stress data within one meshing cycle is extracted. Finite element method (FEM) software is used to simulate the meshing of the face gear pair within one cycle to obtain the tooth root stress F. f Meshing force F at the gear meshing point m Establish a mapping relationship between the two within the meshing cycle.

[0017] F mi =K i F fi

[0018] In the formula, K is the mapping coefficient between the two, and i represents the i-th meshing point.

[0019] The dynamic meshing force at different meshing points is calculated based on the correlation between the tooth root stress obtained from experiments and the stress from finite element simulation.

[0020] The dynamic load sharing coefficient is based on the dynamic meshing force obtained at the root of the face gear and the root of the planetary gear. Three times are selected: engagement point t1, node t2, and disengagement point t3. The root mean square value at different planetary gear locations is calculated. The dynamic load-equalizing factor is calculated using the following formula:

[0021]

[0022] In the formula, the subscript j represents the j-th planetary gear, and j = (1 to n).

[0023] The dynamic load sharing coefficient of the face gear planetary transmission is selected by choosing the larger value of the dynamic load sharing coefficient at the root of the face gear and the root of the planetary gear as the dynamic load sharing coefficient of the system.

[0024] Optionally, the dynamic load sharing coefficient can be replaced by the average value δa of the dynamic meshing force at different meshing points for calculation, as shown in the following formula:

[0025]

[0026] In the formula, the subscript j represents the j-th planetary gear, and j = (1 to n).

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] This invention constructs a dynamic load-sharing test platform and method for a face gear planetary transmission system. This platform can simultaneously acquire the root stress values ​​of the face gear and planetary gears, overcoming the limitation of traditional tests that can only monitor the stress of a single component. Simultaneously, it innovatively proposes a method for calculating the dynamic meshing force at the meshing point of the tooth surface based on the root stress, solving the technical problem of directly measuring the dynamic meshing force. Through the above design, the influence of manufacturing errors, installation clearances, and elastic deformation on the system load distribution is clarified, and the dynamic load-sharing characteristics are accurately quantified. This provides more comprehensive experimental support for the structural optimization of face gear planetary transmissions, thereby overcoming testing technology bottlenecks and promoting their engineering application in high-end equipment. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the test bench of the present invention.

[0030] Figure 2 This is a flowchart of the dynamic load sharing coefficient calculation for the present invention.

[0031] Figure 3 This is a finite element simulation diagram of the face gear pair of the present invention.

[0032] Figure 4 This is a schematic diagram of the face gear planetary transmission system and strain gauge bonding positions of the present invention. Detailed Implementation

[0033] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the invention. After reading this invention, any modifications of the invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0034] This invention relates to a dynamic load-sharing test platform and test method system for a surface gear planetary transmission system. The test platform is as follows: Figure 1 As shown, it includes a frame (1), a drive motor (2), coupling one (3), a torque sensor (4), coupling two (5), a speed-increasing gearbox (6), a speed-increasing large gear (7), a large gear shaft (8), a speed-increasing small gear (9), a small gear shaft (10), a spline (11), a face gear planetary transmission gearbox (12), a face gear (13), a planetary cylindrical gear (14), a planetary carrier (15), a face gear (16), coupling four (17), a torque sensor (18), coupling five (19), a magnetic powder brake (20), a slip ring (21), and a signal acquisition instrument (22), etc.

[0035] The drive motor (2) is mounted on the frame (1). The output shaft of the drive motor (2) is connected to one end of the torque sensor (4) through a coupling (3). The other end of the torque sensor (4) is connected to the large gear shaft (8) of the speed-increasing gearbox. The speed-increasing large gear (7) is mounted on the large gear shaft (8) through a spline, flat key or interference fit. The large gear (7) meshes with the small gear (9) to perform speed-increasing transmission. It is mounted on the speed-increasing gearbox (6). The small gear shaft (10) is hollow. One end of the small gear shaft (10) is connected to the input face gear shaft (13) of the face gear planetary transmission system through a spline (11). The spline shaft (11) is hollow. The other end of the small gear shaft (10) is connected to a slip ring (21). The slip ring (21) is connected to a signal acquisition instrument (22).

[0036] The input gear (13) has n sets of strain gauges arranged along the circumferential direction at its tooth root, where n is the number of planetary gears (14). The strain gauges are connected to the slip ring (21) via the hollow shaft (10) of the pinion.

[0037] The face gear planetary transmission system includes left and right side gears (13) and face gears (16), a central planet carrier (15) and planet gears (14), and a gearbox (12). The planet carrier is cross-shaped, and the planet gears (14) are mounted on the planet carrier (15). In addition to rotating around the planet carrier, the planet gears can also revolve around it. The power of the face gear planetary transmission system drives the left face gear (13) to rotate through the input shaft. The power is then distributed through the planet gears and converged to the planet carrier (15) for output.

[0038] The output shaft of the planetary carrier (15) is connected to the torque sensor (18) via a coupling (17), and further connected to the magnetic powder brake (20) via a coupling (19). The magnetic powder brake (20) adjusts the braking torque according to the instructions of the control system to achieve precise control of the system load.

[0039] Optionally, the power is input from the face gear (13) and output from the planet carrier (15), which can be replaced by the power being input from the planet carrier (15) and output from the face gear (13).

[0040] To ensure the stability and accuracy of power transmission, the drive motor (2), coupling one (3), and torque sensor one (4) are on the same straight line. Similarly, the output shaft of the planetary carrier (15), torque sensor two (18), and magnetic powder brake (20) are on the same straight line.

[0041] Optionally, the large and small gears (7) and (9) of the speed-increasing gearbox can be single-stage meshing transmissions of spur gears, helical gears and herringbone gears.

[0042] Optionally, the left and right face gears (13) and (16) can be spur gears, helical gears and herringbone gears.

[0043] An offline stress-strain signal acquisition system is installed on the tooth roots of the n planetary gears (14) to read the data after the test is completed.

[0044] Optional: The offline strain gauge can be attached to the tooth surface at the tooth root or to the tooth root end face, and the attachment position is determined by the 30° critical section method.

[0045] The dynamic load-sharing test mainly measures the stress value F at the root of the gear (13) using strain gauges. f1 The stress value F at the root of the n planetary gears (14) f2 The tooth root stress value can be collected at the tooth surface of a face gear or a cylindrical gear, or at the tooth root end face.

[0046] The obtained tooth root stress data is filtered, and then the stress data within one meshing cycle is extracted. The meshing of the face gear pair within one cycle is simulated using finite element software to obtain the tooth root stress F. f Meshing force F at the gear meshing point m Establish a mapping relationship between the two within the meshing cycle.

[0047] F m =K i F fi

[0048] In the formula, K is the mapping coefficient between the two, and i represents the i-th meshing point.

[0049] The dynamic meshing force at different meshing points is calculated based on the correlation between the tooth root stress obtained from experiments and the stress from finite element simulation.

[0050] The dynamic load sharing coefficient is based on the dynamic meshing force obtained at the root of the face gear and the root of the planetary gear. Three times are selected: engagement point t1, node t2, and disengagement point t3. The root mean square value at different planetary gear locations is calculated. The dynamic load-equalizing factor is calculated using the following formula:

[0051]

[0052] In the formula, the subscript j represents the j-th planetary gear, and j = (1 to n).

[0053] The dynamic load sharing coefficient of the face gear planetary transmission is selected by choosing the larger value of the dynamic load sharing coefficient at the root of the face gear and the root of the planetary gear as the dynamic load sharing coefficient of the system.

[0054] Optionally, the dynamic load sharing coefficient can be replaced by the average value δa of the dynamic meshing force at different meshing points for calculation, as shown in the following formula:

[0055]

[0056] In the formula, the subscript j represents the j-th planetary gear, and j = (1 to n).

[0057] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A dynamic load-sharing test platform and test method for a face gear planetary transmission system, characterized in that, The testing platform includes a frame, drive motor, speed-increasing gearbox, face gear planetary transmission system, magnetic powder brake, torque sensor, slip ring, stress-strain testing system, etc. The drive motor is connected to a torque sensor, and then further connected to the large gear of the speed-increasing gearbox. The small gear shaft of the speed-increasing gearbox is hollow, with one end connected to the input face gear shaft of the face gear planetary transmission system, and the other end connected to a slip ring. The slip ring is connected to a stress-strain signal acquisition instrument. The face gear planetary transmission system includes two face gears (left and right), n planet gears, and a planet carrier. Power is input through the left face gear and output through the planet carrier. The output shaft of the planet carrier is connected to a torque sensor via a coupling, and further connected to a magnetic powder brake. Each of the n planetary gears is equipped with an offline stress-strain signal acquisition system to read data after the test is completed.

2. The dynamic load-sharing test platform and test method for a face gear planetary transmission system according to claim 1, characterized in that, Dynamic load sharing tests primarily involve measuring the stress values ​​at the tooth roots of face gears and planetary gears using strain gauges. The data is then filtered, and stress data within one meshing cycle is extracted. Finite element simulation is used to obtain the correlation between tooth root stress and meshing force at the gear meshing point. Based on the tooth root stress and the finite element simulation results, the dynamic meshing force at different meshing points is obtained.

3. The dynamic load-sharing test platform and test method for a face gear planetary transmission system according to claim 1, characterized in that, Based on the dynamic meshing forces obtained at the tooth roots of the face gear and planetary gear, three time points—t1 (engagement point), t2 (pitch point), and t3 (disengagement point)—were selected. The root mean square (RMS) values ​​at different planetary gear locations were calculated. Or the average value δa, the dynamic load-sharing factor is calculated according to the following formula: or In the formula, the subscript j represents the j-th planetary gear, and j = (1 to n).

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