Tractor MFWD braking deceleration research between different wheel drive

Abstract

Abstract. The article presents and analyses the reasons of the braking parameter in 4×4 tractor. It is noted that the wheeled tractors are working in transport, cargo, driving with implements and without them in the fields, etc. for most of the time. The contact area with the road surface during braking decreases when increasing the driving speed and the overall dynamic stiffness of the tire changing increases the rolling resistance. However, it is worth mentioning that the tire contact with the road surface area is also dependent on the tire air pressure and improperly selected or uneven tire air pressure to increase the vehicle rolling resistance, increasing the frontwheel lead, which reduces the braking efficiency. The change of the front-wheel lead increases kinematic discrepancy between the drive wheels. These factors have negative effect for the tractor performance parameters, the transmission is loaded heavily, the power losses are increased, tires wear faster, the fuel consumption is increased. This article shows and analyses tractor deceleration between different wheel drive (4×2 and 4×4) with different driving speed.Keywords: inflation pressure, deceleration, braking, agricultural tractor. IntroductionTractors are identified as MFWD (Mechanical Front-Wheel Drive) tractors, when the front axle is driven by a mechanical drive and the front drive wheels are smaller than the rear wheels. Today, MFWD tractors are extensively used for transportation work when connected to the tractor trailer or semi-trailer. The latter considerably increases the tractor rear wheel vertical load and the rear tire deformation, but reduces the front-wheel vertical load and tire deformation. Increasing and decreasing the rear of the front tire deformation increases the actual size of the front wheel advance. This change has no harmful effects on the tractor vehicle dynamics while working, because when running a good road and at higher speed, the front wheel drive is generally unplugged. However, front-wheel accelerates change effects of the MFWD tractor braking dynamics, since the braking front axle is always automatically enabled [1][2][3][4].Brake and steering systems in vehicles are the most effective gear, which directly affects the vehicle dynamics. In general, the brake system is running in the longitudinal vehicle dynamics and driving dynamics system running side. However, their effects combine when the vehicle is braked on uneven surfaces. The yaw moment braking compensates for steering control on the road. To avoid improper steering compensation vehicles have been equipped with the wheels being driven in rotation angle of the controller, designed to mitigate the impact of asymmetric braking forces and stabilize the angular deviation in vehicles [5][6][7].Freight transportation tractors are combined with various trailers or semi-trailers. Almost 75 % of kinetic energy of the tractor-trailer combination is acquired from the trailer, so it is very important that the brake system of the trailer is sufficient to defeat the e...

Braking Efficiency and Stability of Chassis Braking System of Combine Harvester: The Theoretical Derivation and Virtual Prototype Simulation

“…The chassis braking system mainly consist of the brake pedal, the brake master cylinder, the brake wheel cylinder, and the brake actuator. Since the force directly applied on the brake pedal is too small to produce enough braking force, the pedal force should be multistage amplified, orderly by the mechanical force amplifier (i.e., the brake arm (2)), and the hydraulic force amplifier (i.e., the brake master cylinder (5) and the brake wheel cylinder (11,15)), to ensure that the combine harvester is reliably braked. As shown in Figure 1(a), (8) and (13), the brake disks are designed as a caliper-disclike structure.…”

“…According to (4) and (5), when the front and rear wheel are locked at the same time, the relationship between F 1 and 2 is shown in…”

“…In recent years, several methods have been proposed to evaluate the performance of the combine harvesters in a laborious and inaccurate filedtest way. Moreover, these studies on the braking system of agricultural machinery vehicles are mainly limited to tractors, and most of the studies are focused on the optimization of a certain part of braking system or simulation analysis of the braking efficiency, while there are few studies of the braking system of combine harvesters, particularly the braking directional stability [1][2][3][4][5][6][7]. It is still a challenge to evaluate their performance in a theoretical derivation-based simulation way.…”