Rear Axle Research Articles

Modeling and characteristic analysis of mid-rear axle hydraulically interconnected suspensions for tri-axle heavy trucks

Truck suspension is a vital component supporting the weight of the vehicle body and plays an important role in transferring wheel load and isolating external vibration. The uneven load distribution between the middle and rear wheels of a tri-axle heavy truck will directly affect the driving stability and safety of the vehicle. To enhance the truck’s wheel load distribution performance and ride comfort, this paper proposes a new coupling suspension system, including an anti-synchronous middle and rear axle hydraulically interconnected suspension (MR-HIS) and the front axle conventional independent suspension (CIS). Considering the load-bearing characteristics of the middle and rear wheels of the tri-axle heavy truck, a five-degree-of-freedom (5-DOF) half-vehicle model of the truck equipped with MR-HIS is constructed. Further, the dynamics equations of the mechanical-hydraulic coupling system are established according to the impedance transfer matrix method and mechanical-hydraulic boundary conditions, and the truck body motion modes are completely decoupled. The modal analysis demonstrates that compared with CIS the proposed MR-HIS system can reduce the body bounce modal stiffness, increase the modal damping ratio, and enhance the dynamic coupling performance of middle and rear wheels. Subsequently, the frequency response analysis is adopted to evaluate the load distribution and vibration isolation performance of the MR-HIS. The comparison analysis results indicate that the proposed MR-HIS system significantly improves the load balance distribution between the middle and rear wheels and suppresses the load transfer to the front wheel, thus the handling stability of the truck is improved. Meanwhile, the body vibration frequency response analysis shows that the MR-HIS can effectively isolate external vibration and improve driving comfort of the tri-axle heavy truck.

Bifurcation analysis of a rear axle tramp car model

Axle tramp is a self-sustaining vibration in the driven axle of a vehicle with a beam axle layout, known to occur under heavy braking or acceleration. A 6DOF mathematical model of this phenomenon is used to identify how the key parameters of driveline stiffness, axle mass and fore/aft stiffness change the system’s dynamics. A bifurcation analysis is performed to study this nonlinear system’s dynamics. Four Hopf bifurcations in the underlying equilibria, along with a fold bifurcation in the outermost limit cycle branch, are shown to bound the parameter space where tramp occurs. The severity of tramp was found to be minimised by increasing drivetrain stiffness, reducing axle mass or increasing fore/aft stiffness: the trade-off for minimising tramp severity is that it may be easier to excite tramp when the drivetrain stiffness is increased, and the speed range over which tramp can occur is increased as fore/aft stiffness is increased. A key outcome from this work is that future electrified powertrains may experience more tramp, albeit at a reduced magnitude, than their combustion-powered counterparts.

Torque Load Analysis on Rear Axle Shaft Material AISI 4340 Normalized

The choice of rear axle shaft material on the car needs to be considered because this component affects the performance of the car. This component material is also very necessary, the selection of components used is AISI 4340 Steel Normalized, where this material contains Nickel, Chrom, and Molybden with the characteristics of the AISI 4340 Steel Normalized material is a steel material that has high hardness properties, can accept great pressure and force and not easy to deform. The method used is the Finite Element Method (FEM), this method uses a meshing size of 5 mm, to get more accurate results. Simulation results from rear axle shaft AISI 4340 Steel Normalized to determine the value of stress, strain, and safety factor from load variations of 1200 Nm, 1400 Nm, 1600 Nm, and 2000. The highest maximum stress value occurs at 2000 Nm torque load of 5.586 x 108 Nm. The highest maximum strain value occurs at a torque load of 2000 Nm of 5.034 x 103. The safest value of the safety factor is 2.1 at a torque load of 1200 Nm. The torque load value is directly proportional to the stress and strain values ​​obtained, because the greater the torque load value, the greater the stress and strain values ​​obtained.

Design of The Pyrolysis Furnace for The Alternative Energy

The pyrolysis furnace material needs to be considered because this component affects the performance of the pyrolysis process. This component material is also essential; the selection of components used is AISI 4340 Normalized Steel, where this material contains Nickel, Chrom, and Molybdenum, with the characteristics of the AISI 4340 Normalized Steel material, which is a steel material that has high hardness properties, can accept significant pressures and forces and is not easily deformed. The method used is Finite Element Analysis (FEA); this method uses a mesh size of 5 mm to get more accurate results. Simulation results of the AISI 4340 Steel Normalized rear axle shaft to determine the values of stress, strain, displacement, and safety factor from temperature variations of 150 °C, 175 °C, 200 °C and 225 °C. The highest maximum stress value occurs at a temperature of 225 °C of 7.339 x 108 Nm. The highest maximum strain value occurs at a temperature of 225 °C of 1.892 x 10 3. The highest displacement value occurs at a temperature of 225 °C of 4.891 x 10 1. The safest safety factor value to use is 1.547 at a temperature of 150 °C. The temperature value is directly proportional to the stress and strain values obtained because the more significant the given temperature value, the greater the stress and strain values.

OPTIMALISASI DESAIN TRUK JUNGKIT CATERPILLAR 777D UNTUK PENGANGKUTAN BATU BARA

In the world of coal mining the use of heavy equipment is absolute. The use of heavy equipment in coal mining is a job that requires optimal production capabilities of heavy equipment, because there are large volumes of excavation work, stockpiling and transportation of material. The standard body design on the Caterpillar 777D dump truck has not been specifically designed for transporting coal materials, so it is not ideal. This study aims to design a dump truck body by adding a larger body capacity than the standard body. The standard used for determining the mass of material to be transported is in accordance with ISO 6483: 1980. After obtaining a new body design using Autodesk Inventor software, the weight of the body and the weight of the coal to be transported will be known, after that the load distribution calculation on the axles will be carried out. front and rear axles. Load distribution will be limited by the maximum load allowed on the front axle and rear axle according to the regulations specified on the Caterpillar 777D unit. Having obtained a new body design with a more optimal transport volume capacity, it will be very useful for more efficient coal transportation. So it was concluded that the results of the analysis of the Caterpillar 777D tub specifically for coal transportation can exceed the standard volume capacity with a volume capacity of 120 m3.

Torque Vectoring Control Strategies Comparison for Hybrid Vehicles with Two Rear Electric Motors

In today’s automotive industry, electrification is a major trend. In-wheel electric motors are among the most promising technologies yet to be fully developed. Indeed, the presence of multiple in-wheel motors acting as independent actuators allows for the implementation of innovative active systems and control strategies. This paper analyzes different design possibilities for a torque vectoring system applied to an originally compact front-wheel drive hybrid electric vehicle with one internal combustion engine for the front axle and two added electric motors integrated in the wheels of the rear axle. A 14 degrees of freedom vehicle model is present o accurately reproduce the nonlinearities of vehicle dynamic phenomena and exploited to obtain high-fidelity numerical simulation results. Different control methods are compared, a PID, an LQR, and four different sliding mode control strategies. All controllers achieve sufficiently good results in terms of lateral dynamics compared with the basic hybrid version. The various aspects and features of the different strategies are analyzed and discussed. Chattering reduction strategies are developed to improve the performance of sliding mode controllers. For a complete overview, control systems are compared using a performance factor that weighs control accuracy and effort in different driving maneuvers, i.e., ramp and step steering maneuvers performed under quite different conditions ranging up to the limits.

Opportunities and limitations of computer simulation of technological machines

Problem. Mobile lifts with working platforms have found wide application in various fields of industry. One of the main requirements when designing such machines is to ensure the stability and trouble-free performance of technological operations. The article presents the results of the development of a digital three-dimensional model of such a machine, and also describes virtual studies on controlling the machine's movement at different positions of the running gear. Goal. It was decided to divide the entire set of tasks to be solved into clusters in which it is possible to obtain reliable information with minimal time for the development of the models, as well as with the least load of the software. The main task was to develop a computer model of the running gear to study the maneuverability of the machine. Methodology. Geometric modeling was performed with limited initial data, the properties of the materials used for parts were not taken into account, and welding was not modeled. However, the geometry of the frame and all components was reproduced almost completely in the dimensions and configurations of the real object. Results. The computer model enabled establishing of the dependence of the machine's turning radii from the geometric design parameters of the chassis, as well as from the turning patterns and position of the longitudinal beams. Originality. The computer model made it possible to maneuver in three independent schemes: the classic 4x2 wheeled vehicle turning mechanism, turning with all four wheels (on the front and rear axles in opposite directions), and when all wheels turn in one direction, the so-called "crab stroke". Practical value. The proposed models and algorithms will significantly speed up the design process for this class of vehicles.

Modeling of Running Equipment of Mobile Lifts

Problem. Mobile lifts with working platforms have found wide application in various fields of industry. One of the main requirements when designing such machines is to ensure the stability and trouble-free performance of technological operations. The article presents the results of the development of a digital three-dimensional model of such a machine, and also describes virtual studies on controlling the machine's movement at different positions of the running gear. Goal. It was decided to divide the entire set of tasks to be solved into clusters in which it is possible to obtain reliable information with minimal time for the development of the models, as well as with the least load of the software. The main task was to develop a computer model of the running gear to study the maneuverability of the machine. Methodology. Geometric modeling was performed with limited initial data, the properties of the materials used for parts were not taken into account, and welding was not modeled. However, the geometry of the frame and all components was reproduced almost completely in the dimensions and configurations of the real object. Results. The computer model enabled establishing of the dependence of the machine's turning radii from the geometric design parameters of the chassis, as well as from the turning patterns and position of the longitudinal beams. Originality. The computer model made it possible to maneuver in three independent schemes: the classic 4x2 wheeled vehicle turning mechanism, turning with all four wheels (on the front and rear axles in opposite directions), and when all wheels turn in one direction, the so-called "crab stroke". Practical value. The proposed models and algorithms will significantly speed up the design process for this class of vehicles.

Study of the interaction of a short-base loader with a supporting surface during transport operations

Problem. The relevance of the work is to create and improve loading and unloading machines. Goal. The article deals with the transport mode of the PMTS 1200 short-base loader, namely the process of moving over a single obstacle. Methodology. Due to the short base and the center of gravity, which is structurally located closer to the rear axle, the machine loses stability when overcoming unevenness in the working surface due to the rear wheels coming off the bearing surface, which reduces its efficiency and productivity. Results. Therefore, there is a need to increase the efficiency of short wheel loaders when overcoming unevenness on the work site by using an intelligent control system in the transport mode, which increases the stability of the machine.Originality.. On the other hand, machine control automation systems require consideration of the transport mode, mathematical modeling of the machine, and algorithmization of work processes, as these parameters are essential for the development of control systems. Thus, the creation of adaptive systems for automatic control of short-base loaders is an urgent scientific and technical problem, the solution of which is of great economic importance for the construction industry. Practical value. Using the developed mathematical models, the dependencies characterizing the interaction of the forklift wheels with the bearing surface were obtained, which are complex in nature but reflect the interaction of a short wheel loader with an obstacle and can be used to assess the stability of the machine and the traction capabilities of its individual wheels.

IMPROVING MANEUVERABILITY OF A WHEELED VEHICLE BY IMPROVING TURN CONTROL METHOD

A large number of scientific works and design developments are devoted to the study and improvement of the properties of maneuverability, which is also a complex (complex) property. At one time, the need to reduce the building volume required the installation of swivel wheels on the front steering axle of the car. However, in this case, additional resistance to the movement of the machine arose, which is due to the discrepancy between the trajectories of the movement of the front outer and inner guide wheels with their trajectories during an ideal turn. The development of the designs of electric vehicles and hybrid vehicles allows for separate control of the front wheels. The analysis of the whole variety of indicators and criteria of maneuverability in general and individual properties was carried out. Unlike other systematization of these indicators and criteria, it is proposed to divide these indicators and criteria into three main groups. All indicators and criteria used to assess the maneuverability of vehicles are also used to assess the maneuverability of wheeled tractors with a center of mass shifted to the rear axle and, therefore, have low controllability. Force and energy criteria can be used in the design of cars and tractors to ensure the ability of the latter to maneuver. In addition, as a result of the study, a combined method for controlling the movement of a two-axle swivel bogie of a wheeled vehicle has been improved due to the fact that its rotation is carried out by two torque control moments. The first of these control torques is generated by the driver through the steering and power cylinder. The second torque control moment is created due to the difference in torques on the wheels of the outer and inner sides of the two-axle swivel bogie. The implementation of these rules for regulating the distribution of traction forces between the sides makes it possible to overcome the resistance to rotation of a two-axle swivel bogie and improve the quality of motion control of the specified bogie and wheeled vehicle. Keywords: maneuverability, separate control, wheeled vehicle, control method, two-axle swivel bogie

Reaction Rod Link in Rear Cab Suspension to Control Cab Dynamics in Tractor-Semitrailer Vehicles

<div>Articulated vehicles form an important part of our society for the transport of goods. Compared to rigid trucks, tractor-trailer combinations can transport huge quantities of load without increasing the axle load. The fifth wheel (FW) acts as a bridge between the tractor and trailer, which can be moved within the range to achieve rated front and rear axle loads. When the FW is moved front, it adversely affects the cab dynamics and cab suspension forces. Compared to the cab pitch and roll, yaw motion increases drastically. The current study tries to address this issue by providing reaction rod links in the rear cab suspension.</div> <div>In this study, a 4×2 tractor with a three-axle semitrailer is considered by keeping the FW at its frontmost position, which is the worst-case scenario for a cab. Three different cases of reaction rod arrangement and its influence on cab dynamics are studied in comparison with a model without reaction rods. To assess this, time signal–based relative pseudo-fatigue damage, power spectral density (PSD), and level crossing plots are analyzed.</div> <div>The outcome shows that cab pitch, roll, and yaw motion reduce by a considerable amount with the presence of a reaction rod. Cab suspension forces will also reduce. The horizontal V-inclination of the reaction rod plays a major role in improving cab yaw motion and reducing the lateral forces. A straight link without any inclination helps in reducing the pitch and roll motion of the cab.</div>

Leveling Control of Hillside Tractor Body Based on Fuzzy Sliding Mode Variable Structure

To address the issues that arise when auto-leveling the vehicle body of a hillside tractor under complex working conditions, an auto-leveling control system was developed based on a newly developed hillside tractor and four-point body leveling mechanism. In this approach, leveling accuracy and stability were improved by adopting a sliding mode variable structure control algorithm based on fuzzy switching gain adjustment to achieve real-time dynamic auto-leveling control. To obtain curves of front and rear axle leveling displacement, speed, flow, pressure and body tilting angle during the leveling process, AMEsim/Simulink co-simulation was used to simulate and analyze the control system. The simulation results revealed that the tractor achieves a good leveling effect under complex working conditions in hilly and mountainous areas; the tractor can remain within a ±2° tilting angle range during the leveling process and can return to 0° after leveling, demonstrating good dynamic stability. To further assess the algorithm, a model of the system was submitted to live-testing on a custom-built auto-leveling test bench. Comparison of the test and simulation results revealed a close agreement between the two, indicating that the self-leveling control system and control algorithm developed in this study have high leveling accuracies. The results reported in this paper could provide assistance with or in reference to obtaining solutions to the problems of tractor body leveling in hilly and mountainous areas.

DESIGN FEATURES OF CASE AGRICULTURAL TRACTORS

Leading firms and corporations - manufacturers of agricultural machinery (hereinafter referred to as companies) develop, produce, and then offer tractor models on the market in the form of construction series combining up to 40-55 models. The largest companies produce not only tractors, but also sets of agricultural machines for them, as well as entire technological complexes for processing and harvesting one or another crop. Thus, these companies act on the markets with their own product programs, which include the construction series of tractors as the most important component (Deere & Co, Case, New Holland, Massey Ferguson, etc.). Each construction series includes several (up to 10) series (families) of tractor models, identical in purpose, differing in engine power. The basis of each such family is unified aggregates and units - engines, transmissions, front and rear axles, hydraulic suspension systems, cabins, electrical equipment and other aggregates. The tractors of the construction series have a single stylistic solution of the cabin and external structure, which is a trademark. The construction series is characterized by a high saturation of models, especially in the range of small and medium capacities, which is explained by the increased demand for tractors of these capacities. The redundancy of models is especially noticeable in the design series of companies that were formed by merging companies that previously had their own design series (for example, the Case New Holland Company). Design series are built according to engine power and tractor weight, series - according to engine power, the gradation of which is determined by the number of engine cylinders and the possibility of forcing it with the help of low or high turbocharging. Often, the models of the series, and especially the series, have very little difference in engine power, which, with the redundancy of a number of models, allows companies to meet the demands of the maximum number of consumers for tractor performance and fuel consumption in competitive conditions.

Innovative Axle Concept

German automotive engineering consultancy, EDAG, has devised a modular chassis concept with front and rear axle designs the likes of which have never been seen before

Methodology for Assessing Tractor Traction Properties with Instability of Coupling Weight

The purpose of the study is to increase the efficiency of using the tractor hitch weight in traction mode by reducing the uneven distribution of vertical reactions between the wheels. This work is grounded on a methodology that involves summarizing and analyzing established scientific findings related to the theory of tractors operating in traction mode. The analytical method and comparative analysis were employed to establish a scientific problem, define research objectives, and achieve the goal. The key principles of probability theory were applied in developing the empirical models of the tractor. The main provisions of the methodology for evaluating the traction properties of the tractor with the instability of the coupling weight were formulated. The method of evaluating the vertical reactions on the wheels of the tractor is substantiated, which is based on the measurement of the vertical reaction on one of the four wheels. It was proven that tractors with a center of mass offset to the front or rear axles have the greatest probability of equal distribution of vertical reactions between the wheels of one axle, and tractors with a center of mass in the middle between the axles have the lowest probability. It is theoretically substantiated and experimentally confirmed that when the tractor performs plowing work with uneven distribution of loads on the sides, its operation with maximum traction efficiency is ensured by blocking the front and rear axle drivers.

ОСОБЕННОСТИ КОНСТРУКЦИИ ТРАКТОРОВ ДЛЯ РАБОТЫ НА СКЛОНАХ

The problems of creating tractors, self-propelled chassis, forestry and agricultural machines of special designs for the mechanization of crop production, land reclamation and construction in hard-to-reach conditions of forest, agricultural and mountain lands are considered in the work. A comparative analysis of design solutions that have found application in domestic and foreign tractors used in the performance of technological and transport operations on sloping lands and badlands in agriculture and forestry is given. It is noted that a number of models of universal row-crop tractors provide for the possibility of increasing stability by turning the housings of the remote final drives relative to the rear axle housing. For tractors, at the same time, the wheelbase increases and the ground clearance (ground clearance) decreases. It is indicated that the analysis of the features of the operation of wheeled tractors on the slopes made it possible to substantiate the methods and means that improve their main indicators: differential lock; lowering the center of gravity; the use of tires with high lugs, additional steel wheels, lugs, expanders; the use of half-tracks and wheeled tractors with a 4K4 wheel arrangement. The advantages and disadvantages of using tracked and wheeled tractors as the base machine have been established. Slope preference for tractors with front drive axle. Such tractors, equipped with the previously listed devices, have better traction properties, maneuverability and controllability, approaching caterpillar tractors in these indicators. Recommendations for the implementation on slopes, forest and agricultural lands of all-wheel drive low-clearance wheeled tractors are given in the work. In conclusion, it is indicated that, despite the considered features, when creating tractors for working on small-contour plots located on slopes up to 25 °, preference is given to wheeled low-clearance tractors, which is caused by a cheap design due to minor design changes compared to the basic models.

Modeling and Analysis of Differential Gear Box using Ansys

The differential is a component of the rear axles, along with the wheels, bearings, and the inner axle housing assembly. Transmission gears in the differential link the rear wheels to the engine, which in turn powers the propeller. When turning, a car's differential gear arrangement creates a speed difference between the left and right driving axles. Outside wheels have further to travel in a turn than inside wheels. To provide this torque variation, a differential gear system constructed from a variety of materials using a refined 3-D model of the gear system is an option. Additionally, it transmits the power from the propeller shaft to each wheel hub. It takes a differential gear system at each wheel hub for an all-wheel drive system, whereas a rear-wheel drive system only needs one at the back.

Test methodology for validating tractor structural part under multiaxial loading

A tractor is a machine which is predominantly used for various agricultural operations such as plowing, tilling, planting, harvesting, etc. Apart from the regular agricultural applications, currently, tractor is being also used for various other applications such as haulage, dozing, loading, digging, and so on. Because of the versatility in usage patterns and applications, it is extremely difficult to estimate the loads coming on different structural parts of a tractor. Therefore, fatigue behaviors of different structural parts are also highly unpredictable. Limited test methodologies or information are available about the testing methodologies to validate the structural parts of a tractor. Conventional uniaxial load tests may not be sufficient to replicate actual Real World Usage Pattern (RWUP) as different structural failures are reported from field testing or end customers despite clearing in different lab testing. On the other hand, multiaxial loading may produce more realistic and accurate test results. In this paper, an attempt has been made to develop a practically deployable and simple to use laboratory test methodology considering multiaxial loading to validate Rear Axle Carrier (RAC) assembly of a tractor. At the end of the study, simple to put methodology has been demonstrated in which all the stated objectives were full filled. Real time acquired load data have been used to analyze and develop the duty cycle with a considerable test time reduction in place. This methodology can be used for validating similar kind of structures.

Roll dynamic model and steering stability analysis of the counterbalance forklift truck with considering hierarchical rollover

The dynamic model of a counterbalance forklift truck is established, and the validations under various operational conditions are studied. The roll motion of the counterbalance forklift is expressed by four degrees of freedom with consideration given to the independent roll motion between the body and chassis, the variation of the roll axis, and the contact between the body limit block and rear axle. Furthermore, testing under turning on firm ground and driving over obstacle conditions are conducted for verifying the dynamic response characteristic of the established model. In addition, numerical simulations are performed to investigate the effect of forklift structural parameters and road roughness excitation on the roll dynamics of forklifts. Finally, the rationality of evaluating the forklift roll state by load transfer ratio (LTR) is discussed. Simulation results are well in harmony with experiment results, suggesting that the proposed dynamic model can be an effective tool for stability analysis of counterbalance forklift trucks. This work provides theoretical foundations for the development of improved anti-rollover control, ultimately leading to enhanced stability and safety of forklifts.

"DEVELOPMENT OF THE CONCEPT OF A HYBRID POWER PLANT BASED ON A CAR "

"The article reflects information about the current state of development of car designs with a hybrid power plant. The authors are conducting research work to create a prototype of an energy-efficient hybrid power plant based on a passenger car. The result of the work is an increase in the environmental safety of cars and efficiency. The basic schematic diagrams of hybrid power systems of passenger cars have been studied. Hybrid drive options included a version for rear-wheel drive and all-wheel drive layouts. The power plant of a hybrid car with a parallel, sequential and series-parallel construction scheme is considered. Taking into account the advantages and disadvantages of all types of hybrid car drive schemes, the most suitable one has been selected. A small-sized car «Oka» was chosen as the base for the project. The car is modified to all-wheel drive, the electric motor is installed on the rear axle. The article contains a brief traction and dynamic calculation of an electric vehicle. According to the calculation results, an electric motor was selected. The technical solution is to develop an independent rear suspension with a subframe for mounting a gearbox with an electric motor and using hinges of equal angular velocities, which increases the cost of its design, but is the optimal solution for implementing such a scheme. Keywords: hybrid power plant, drive, electric motor, transmission, generator, car."