Research On Electric Tractor Braking System Based On Direct Drive Braking

Traditional diesel-fueled tractors generate a large amount of vibration,noise,and exhaust pollution during operation,and are not suitable for operation in a closed greenhouse.The electric energy has the advantages of green cleaning,energy saving and cost reduction,convenient production and use,etc.,which makes electric power-powered electric tractors emerge as the times require,and has gradually become one of the development trends of future tractors.The brake system is one of the most important components on the tractor and guarantees the safe driving of the tractor.At present,the brake system on the tractor is almost always equipped with a hydraulic brake system.Since the electric tractor does not have an internal combustion engine system,the brake system using the hydraulic brake system will require multiple energy conversions and transmissions,and the structure is complicated,the energy utilization efficiency is not high,the brake fluid leaks,and the hydraulic oil overheats the potential danger of the brake failure.There is therefore an urgent need to develop new brake systems that can be matched to electric tractors.This paper designs a new type of direct drive brake unit,eliminating the hydraulic circuit of the traditional brake.The linear motor is used to provide power,and the force amplifying mechanism is used to finally provide braking force to the brake disk.To this end,the following research and experimental work has been carried out mainly:(1)Determine the structure of the linear motor according to the working environment and characteristics of the linear motor,determine the parameters of the linear motor according to the finite element analysis of the electromagnetic field,and complete the two-dimensional three-dimensional design,processing and assembly of the linear motor.(2)Discuss the types of force amplification mechanisms,analyze the advantages and disadvantages of various force amplification mechanisms,and determine that the force amplification mechanism is a lever amplification mechanism.According to the magnification of the force amplifying mechanism,the size of the lever mechanism is calculated,and the design and processing of the caliper and the force amplifying mechanism and the assembly of the entire new direct drive braking system are completed.(3)Design the brake inertia test bench to provide a test platform for the new direct drive brake device.The status quo of the inertia test bench of the automobile brake was investigated.The overall structural design of the test bench,the selection of important components such as the motor,the actual design and manufacture of the base bracket,and the installation and debugging of the entire experimental platform were completed.(4)The mathematical model of the direct drive braking unit is studied in detail,and the joint simulation model is built by Matlab/Simulink and Stateflow.The electromagnetic force of the linear motor and the braking effect of the entire new direct drive brake system were tested on the test bench.The feasibility of the new brake system was verified.