Differential Gear Research Articles

Establishment of a multi-clearance coupled 3D floating nonlinear model and vibration analysis for a coaxial reverse closed differential herringbone gear transmission system

Establishment of a multi-clearance coupled 3D floating nonlinear model and vibration analysis for a coaxial reverse closed differential herringbone gear transmission system

Electromagnetic performance analysis of a novel radial compound differential field-modulated magnetic gears

Purpose The purpose of this study is to propose a new magnetic gearing device and the proposed transmission model can be applied in the field of wind power and wave energy generation gearboxes. Design/methodology/approach A novel radial differential field-modulated two-stage magnetic gear is introduced, using a unique radial differential linkage to integrate two single-stage magnetic gears. This design incorporates a magnetic isolation ring to enhance transmission efficiency by minimizing magnetic interference and preventing power circulation. The two-stage modulating ring rotor operates synchronously via a connecting bridge, ensuring system stability and efficiency. This configuration not only boosts the gear ratio but also maintains a compact structure, improving power density and efficiency. Leveraging the magnetic field modulation and differential transmission, a finite element model of this gear is developed and its electromagnetic performance is analyzed. Findings The torque density of the new radial differential field-modulated two-stage magnetic gear has increased by 44.97% compared to the traditional tandem two-stage magnetic gear. It achieves a high transmission ratio of 64 and maintains comparable power density, indicating strong torque transfer capabilities suitable for low-speed, high-torque applications. During steady-state operation, the torque pulsation difference between the two stages is minimal, ensuring stable working torque. Social implications This research not only propels the forefront of magnetic gear technology through heightened efficiency and streamlined design but also bears profound societal significance in fostering sustainable energy paradigms. By facilitating superior energy conversion efficiencies in wind turbines and wave energy converters, it plays a pivotal role in mitigating carbon emissions and accelerating the global pivot towards cleaner, renewable energy landscapes. Originality/value A magnetic gear transmission device is proposed, which can achieve high power density and large transmission ratio at the same time, and this study provides a useful reference for the design optimization of new high-performance multistage magnetic gears.

Design of a 2R Open-Chain Plug Seedling-Picking Mechanism and Control System Constrained by a Differential Non-Circular Planetary Gear Train

With a focus on the problems of complex structure and accumulated lateral clearance in the single degree of freedom non-circular wheel system seedling-picking mechanism, which leads to poor motion accuracy, trajectory, and attitude, this study developed a 2R open-chain chili plug seedling-picking mechanism (SPM) constrained by a differential non-circular wheel system. The picking arm was driven by a single-stage non-uniform speed transmission mechanism to reproduce the seedling-picking trajectory and attitude. A protruding seedling-picking device, SPM control system, and test bench were designed. A kinematic model of a differential non-circular gear system was established, and an optimization design software for the SPM was developed based on kinematic analysis. The kinematic characteristics of the SPM were analyzed under optimal parameters. This study completed the seedling-picking performance test of the SPM on the control panel. The test showed that the designed chili SPM can sequentially complete the processes of seedling picking, conveying, retracting, pushing, and returning under the automatic control of the test bench without damaging the main root. The lateral root damage rate was 15.7%, effectively ensuring the integrity of the seedling bowl substrate.

Analytical investigation on load sharing characteristics and speed difference of coaxial reverse closed differential herringbone gear transmission system with floating gear and errors

To investigate the influence of gear floating on the load sharing characteristics of the Coaxial Reverse Closed Differential Herringbone Gear Transmission System (CRCDHGTS) and the rotational speed difference between the upper and lower rotors, a dynamic Bending-Torsional-Axial-Pendular (BTAP) model of the CRCDHGTS was established using the centralized parameter method, which considers various excitation factors such as gear floating, errors, Time Varying Meshing Stiffness (TVMS), gyroscopic effect, and tooth friction. It considers the interaction between the closed-stage gear set and the differential-stage gear set, treating the herringbone gear as a symmetric helical gear connected through a receding slot. The dynamic model was solved using the Runge-Kutta method to obtain the dynamic meshing forces for each gear pair under single and combined floating modes. The Dynamic Load Sharing Coefficient (DLSC) of the system, which characterizes the Load Sharing Performance (LSP), was deduced. The load sharing characteristics of different floating modes were analyzed, as well as the influence of different floating displacement on the DLSC. The motion path of the gear floating was also determined. Additionally, the impact of manufacturing error and assembly error of each component on the DLSC under combined floating mode was analyzed. Finally, the influence of gear floating on the output rotation speeds of the upper and lower rotors of the system was investigated. The results indicate that both free-floating of the center gear and combined floating can effectively improve the LSP of the system. When the system adopts combined floating mode, the DLSC of inner and outer meshing changes between 0.91 and 1.09, demonstrating a significant improvement in the LSP. The DLSC of the system increases with the increase in error, with the eccentricity error having a greater impact on the DLSC compared to the assembly error. The optimal floating value for the sun gear is between 0.6 mm and 0.8 mm, while for the planetary gear, it is between 0.4 mm and 0.6 mm. The rotational speed difference between the upper and lower rotors can be controlled within 1r/min. These research findings provide a theoretical basis for further analysis of the dynamic stability and reliability of the system.

Slip modes modeling of electric vehicle asynchronous electric drive

Purpose. Creation a computer model of electric drive of an electric vehicle with the possibility of modeling in slippage modes, as well as the subsequent determination of slippage detection method as early as possible to further reducing or preventing slippage. Methodology. Mathematical analysis and modeling. Findings. Mathematical models in the structural form of the control system, power converter and motor are added in a simplified way, as the blocks. For compiling a computer model, the blocks of the control system and the power converter will be assembled using models of elements of power electric circuits. The model allows the ED simulation with a huge number of parameters varying – modeling slipping processes with one or two wheels, a sharp change in engine parameters, failure of one of the components of the power circuit, etc. Using the Simulink and SimPower packages of the Matlab software package, as well as the block diagram of the electric drive, a computer model of the ED was synthesized. Computer simulation of dynamic processes in the electric drive during a collision, as well as pulling away on the road surface with a reduced coefficient of friction, was carried out. The obtained diagrams fully correspond to the real physical processes occurring in the electric vehicle and give reason to believe that the constructed mathematical and computer models are adequate. Proceeding from this, electromechanical transients in the electric drive during acceleration with slipping and one wheel runover a road surface with reduced traction were obtained and analyzed. As a result of this analysis, the most optimal and reliable way to determine the skidding mode for its further elimination was determined. Originality. Computer model of the asynchronous electric drive of an electric vehicle with a detailed mechanical part, taking into account the mechanical differential gear, was built. The model allows the ED simulation with a huge number of parameters varying – modeling slipping processes with one or two wheels, a sharp change in engine parameters, failure of one of the components of the power circuit, etc. Practical value. Computer simulation was carried out for two modes: start of electric vehicle movement , when one of the wheels has been of on the road surface with a reduced coefficient of adhesion (0,1) since launch and acceleration with a collision with a surface with a reduced coefficient of adhesion (0,1) with one wheel at the moment of time of 6.3 s.

The effect of floating spline parameter on the dynamic characteristic of encased differential planetary gear train

The load sharing performance of encased differential planetary system has a great impact on the operating performance and service life of the transmission system of the coaxial high speed helicopter. In order to improve the load-sharing performance of the gear pair, the influence of different floating spline structural parameters on the load sharing characteristics of the system was studied. Considering the manufacturing error, installation error, time varying meshing stiffness and other factors, the Lagrange equation is used to construct the dynamic model of encased differential planetary gear train with floating spline structure. The effects of input torque, spline clearance, spline shaft stiffness and spline friction coefficient on the load sharing performance of gear pairs were analyzed. The results show that the differential stage system has a better load sharing performance than the encased stage system. The increase of input torque helps to improve the load sharing performance of the system, and the improvement of the encased stage system is more obvious. The floating spline of sun gear of the encased stage has a greater impact on the load sharing performance of the system. Furthermore, increasing the floating spline clearance, reducing spline shaft stiffness or increasing the friction coefficient of the spline can improve the load sharing performance of the system overall.

Dynamic simulation of the differential gear in road vehicles

The differential gear is a mechanism that is part of the kinematic chain of the vehicle’s transmission. The differential gear has the role of dividing the self-propulsion power flow received from the main drive into two branches, each transmitted to a drive wheel, giving them the possibility to rotate with different angular velocities, depending on the driving conditions. The present work presents the possibilities of computer-aided design and 3D modeling of the main drive and differential gear, respectively the bevel pinion, the crown wheel, the planet pinions and the satellites, using Autodesk Inventor Professional. The 3D model of the main drive - differential gear assembly, considered as a mechanism, was subjected to a dynamic study, using the Dynamic Simulation module. This involves the modeling of the kinematic couplings, the definition of the drive movement parameters and the external loads, respectively the graphical visualization of the kinematic and kinetostatic results for the various components of the mechanism, in real operating conditions, during a kinematic cycle. At the same time, based on the obtained results, the analysis by the finite element method of the most critical component elements, under straight-line driving and turning conditions, is presented.

Tooth interior fatigue fracture in automotive differential gears

Tooth Interior Fatigue Fracture (TIFF) is an emerging gear failure mode with significant implications for gear lifetime and reliability, particularly in modern mechanical transmissions subjected to higher loads, smaller sizes, and increased Noise, Vibration, and Harshness (NVH) requirements. This paper investigates fatigue cracks initiated within the interior of pinion and/or side gear teeth in transmission differentials, representing a new area of recent failure detection. Conventional modeling has suggested that TIFF cracks originate in the case/core area of gear teeth, primarily seen in idler transmission gears. However, this study challenges this notion by presenting evidence that cracks often form closer to the middle of the tooth at various heights. These findings indicate the need for a deeper understanding of TIFF, as the existing theoretical descriptions may not fully explain the observed behaviors. By focusing on this novel area of failure, the paper highlights the importance of addressing TIFF to improve the reliability and durability of gears in modern mechanical transmissions.

Numerical Strength Analysis of Laser-Welded Differential Housing and Gear Considering Residual Stress.

In order to avoid slackening of differential housing and gear joined by bolts, the laser-welding process is proposed in this paper, and the strength of a connecting joint was estimated by numerical analysis with consideration of welding residual stress. The process parameters of laser welding for dissimilar materials QT600 cast iron and 20MnCr5 structural alloy steel were introduced, and chemical composition analysis and microstructure analysis were conducted on the welded joints. The finite element model of laser-welded differential housing and gear was established to obtain the welding residual stress by applying a moving heat source. To verify the accuracy of the simulated result, static pressing tests were employed. The maximum tensile residual stress was 319.4 MPa, located at the same point as the maximum temperature. The simulated stress agreed well with the experimental data. Finally, the dynamic strength of laser-welded differential housing and gear under forward, reverse, and start-up conditions was assessed by regarding welding residual stress as the initial stress field, which showed that all safety factors were greater than 1.4.

A New Class of Devices: Magnetic Gear Differentials for Vehicle Drivetrains

Mechanical differentials are essential drivetrain components of automobiles and other wheeled vehicles, allowing the outer drive wheel to rotate faster than the inner drive wheel during turns. This paper presents a comprehensive description of a novel and recently patented alternative based on magnetic gears, which achieves the same functionality while providing distinctive advantages such as reduced maintenance, absence of lubrication, high efficiency. The paper describes the operation principle of such magnetic gear differential and two alternative constructive options, provides a dynamic model which allows the study of the device in driving conditions, presents a description of a prototype and validates finite element simulations with experimental results.

Stress Analysis of Maraging Steel Differential Gear using ANSYS

Abstract: The main purpose of this project paper is to focus on stress analysis of differential gear. For power transmitted from the engine to the rear wheels the differential gear is used. In a Vehicles, the differential gear provides equal power to all drive wheels while allowing each driving wheel to turn at a different angle and different velocity. Basically, while turning around corners, wheels of an automobile spin at differing velocity. Differential gears fails when tooth tension exceeds its safety limit. Therefore, the maximum capacity at the specified load should be determined. Gears analysis is done to minimize stress on gear teeth and prevents the gear to failure. The purpose of this project is to compare the results obtained on different materials (i.e., Maraging steel, aluminium alloy, cast steel) and achieve a suitable material for Differential Gear without any failure using ANSYS and Solid Works software.

Modeling and Structural Analysis of Rear End Differential Gear Box at Different Speeds with Different Materials

The main aim of this project work is to perform mechanical design & structural analysis of differential gear box. This is necessary when the vehicle turns. The Differential gear is a part for all four wheeler, wheel reserved the power from engine to gear box then by drive shaft to differential gear. A differential is a gear train that transmits an engine's torque to the wheels. During a turn, the outer and inner wheels of the vehicle are forced to travel along paths of different radii. A differential allows the outer driving wheel to rotate at a faster speed when compared to the inner driving wheel during a turn. The analysis is conducted to verify the best material for the gears in the gear box at higher speeds by analyzing stress, strain, total deformation and also by considering weight reduction. Generally, materials used for gears and gear shafts are Cast Iron, magnesium alloy, Cast steel. This project is testing different materials like Aluminum alloy material for reducing the weight of the differential gear box. In this work the differential gear box is designed with Catia V5R20 software. The complete design is imported to ANSYS 14.5 software and analyzed. This analysis is conducted to know the best material for gears in the gearbox at high speed. We consider the factors like stress, strain, total deformation. When comparing the stress, strain total deformation values of the three materials like cast steel, aluminum alloy, magnesium alloy for different speeds at 2400 rpm, 4400 and 115N-m torque. By observing analysis the Result will be displayed and compared to find the most suitable design

Explicit Identification of Pointwise Terrain Gradients for Speed Compensation of Four Driving Tracks in Passively Articulated Tracked Mobile Robot

Tracked mobile robots can overcome the limitations of wheeled and legged robots in environments, such as construction and mining, but there are still significant challenges to be addressed in terms of trajectory tracking. This study proposes a kinematic strategy to improve the trajectory-tracking performance of a PASTRo (Passively Articulated Suspension based Track-typed mobile robot), which comprises four tracks, two rockers, a differential gear, and a main body. Due to the difficulties in explicitly identifying track-terrain contact angles, suspension kinematics is used to identify track-terrain contact angles (TTCA) in arbitrarily rough terrains. Thus, the TTCA-based driving velocity projection method is proposed in this study to improve the maneuverability of PASTRo in arbitrarily rough terrains. The RecurDyn-Simulink co-simulator is used to examine the improvement of PASTRo compared to a tracked mobile robot non-suspension version. The results indicate that PASTRo has a 33.3% lower RMS(Root Mean Square) distance error, 56.3% lower RMS directional error, and 43.2% lower RMS offset error than the four-track skid-steer mobile robot (SSMR), even with planar SSMR kinematics. To improve the maneuverability of PASTRo without any information on the rough terrain, the TTCA is calculated from the suspension kinematics, and the TTCA obtained is used for both TTCA-based driving velocity projection methods. The results show that PASTRo, with the TTCA-based driving velocity projection method, has a 39.2% lower RMS distance error, 57.9% lower RMS directional error, and 51.9% lower RMS offset error than the four-track SSMR.

Assessment of Condition Diagnosis System for Axles with Ferrous Particle Sensor

This study presents a condition diagnosis system based on a ferrous particle sensor to estimate the durability of axles in construction equipment. Axles are mechanical devices that play the role of the differential gear in construction equipment that move with wheels and require high reliability. In the durability testing of new axles, failure identification and real-time diagnosis are required. One of the typical failure modes of an axle is increased ferrous-wear particles due to metal-to-metal contact. Therefore, a condition diagnostic program based on the ferrous particle sensor is developed and applied in the bench tests of axles. This program provides information on the amount of wear with respect to ferrous particles using a simple diagnostic algorithm. Additionally, it allows separation and storage of measured data that exceed the reference values; the system provides warnings using color, sound, and pop-up windows to facilitate diagnosis. In the two tests, the first case detected a failure, but in the other case, the sensor did not detect it even though a failure occurred. From the results of bench tests, it is confirmed that the sensor location is a critical factor. Therefore, a multi-physics-based analysis method is suggested for positioning the ferrous particle sensor.

Design and optimization of automotive cardan shafts for industrial applications with enhanced performance and durability

A crucial part of a locomotive is the cardan shaft. A rear-wheel-drive vehicle's differential gear receives power from the engine through a spinning shaft known as a cardan shaft. The cardan shaft must turn at ever-changing angles between the gearbox and axle in order to function. High vibrations are experienced on it as a result of the constant rotation. This issue causes shafts to flex or distort. In this study, a cardan shaft's design and development are carried out. Although it is extensively beneficial in the locomotive industry, vibration is a significant issue with cardan shafts. Creo parametric software was used for developing the design, while Ansys was used to analyze it. Using Ansys software's modal analysis, verify the natural frequency. It is then contrasted with the different shaft cut-out geometries.

Review on power flow and efficiency of a closed differential planetary gear train

The closed differential planetary gear train transmits power in multiple paths, which has large power transmission and compact structure. It is widely used in high-power occasions such as ships. However, the closed differential planetary gear train has many power flow paths and complex structure. If the structural design is unreasonable, there will be power cycle (closed power) in the system, which will seriously reduce the efficiency of the system. There are many components of closed differential planetary gear train, and the uniform distribution of load is of great significance to improve the transmission quality and service life of the system.This paper mainly summarizes the research status of ordinary planetary gears, the power flow analysis status of closed differential planetary gear transmission and the efficiency analysis status of planetary gear transmission.

Electromechanical transmission of an all-wheel drive vehicle with a central traction electric motor

Modern approaches to the construction of a kinematic scheme of an electromechanical transmission are considered. It is shown that for all-wheel drive transport and transport-technological mobile platforms, it is advisable to use a central traction electric motor operating with a two-mode reduction gear connected in series and a transmission based on controlled inter-axle and inter-wheel power distribution mechanisms. It is shown that such a scheme makes it possible to improve the operating conditions of the traction motor, reduce its installed power, dimensions and weight. At the same time, it remains possible to fully control the traction force on the drive wheels, use power recovery, and work in the mode of dynamic stabilization of the motion trajectory. The structure of the electromechanical transmission based on the described principles is proposed. The principles of operation of controlled interaxle and interwheel power distribution mechanisms based on gear differentials are considered. Examples of simplified kinematic schemes of promising mechanisms are given and principles of their control are proposed. The principles of determination of external parameters and synthesis of kinematic schemes of interaxle and interwheel differentials with friction control are considered.

Reduction Technologies of Rear Differential Gear Whine Noise by Controlling Vibration Characteristics of Leaf Suspension

Reduction Technologies of Rear Differential Gear Whine Noise by Controlling Vibration Characteristics of Leaf Suspension

Development of Two-Way Self-Adaptive Gripper Using Differential Gear

In this paper, a two-way self-adaptive gripper that has adaptability to external disturbance loads during linear opening/closing pinch actions and adaptability to encompass a variety of shapes during grasping using a single actuator is proposed, unlike the previous self-adaptive robotic grippers capable of only shape adaptation. Therefore, both linear motion adaptability and shape adaptability during parallel grasping situations are enabled by the proposed design of the gripper. Adaptation to the linear pinch motion is provided through the use of a differential gear, the two outputs of which drive the two tips of the gripper. If facing uneven external loads, the differential gear adaptively alters the speeds of the two outputs, resulting in different closing speeds of the two gripper tips. Despite asymmetric closing, very stable grasping can be guaranteed for such a situation. The differential gear can even complete the grasping by intentionally or unintentionally fixing one of the gripper tips. The proposed design is also capable of shape adaptation in the encompassing grasping mode by adopting a parallel-linkage gripper mechanism, consisting of an exoskeleton and 6 internal joints with a spring element. The finger exoskeleton facilitates pinch and spread actions, while the encompassing action is carried out by adjusting the internal linkage. Based on the kinematic analysis and modeling of the proposed gripper, a prototype of the two-way adaptive gripper hardware was developed. Several experiments were performed to verify the feasibility and validity of the proposed gripper system. The actuator using the proposed differential gear was shown to be able to grasp objects in jammed conditions. In addition, the gripper was able to perform grasping actions, such as pinch, spread, and encompassing grasp.

Comparative Analysis and Design of Double-Rotor Stator-Permanent-Magnet Motors with Magnetic-Differential Application for Electric Vehicles

In order to get rid of the bulky and lossy differential gears and to enhance the system robustness, the magnetic differential (MagD) system is proposed after the mechanical differential (MechD) and electronic differential (ElecD) systems. The MagD system is mainly composed of the double-rotor (DR) stator-permanent-magnet (PM) motor with a new set of winding whose magnetic field reversely interacts with the PM field in two rotors. As a result, the compactness and reliability of the system are improved. This paper quantitatively compares and analyzes the three major types of stator-PM motors applied in the MagD system, which can give an essential guideline on the choice of motor types in various situations. All kinds of motors are optimized in the same exercise, and their performances are thoroughly evaluated and compared by using three-dimensional finite element analysis. Finally, the motor with the best overall performance is prototyped, and the MagD system is set up for experimental verification of the optimized flux-switching PM motor.