Research On Steering Performance Of Front-Axle-Swing-Steering Hydraulic Chassis

China's southern paddy fields are more and mainly small paddy fields,small paddy fields are generally irregular,and thefields of mechanical requirements are higher.Although the market has a variety of paddy field machinery and small agricultural machinery,but cannot meet the small paddy field of mechanical mobility and high operational requirements,this situation greatly restricts the development of agricultural modernization process.In order to solve the dilemma of low mechanization degree of small paddy field in southern China,it is very important to develop a small paddy field agricultural machinery with high working efficiency and low energy consumption per unit area to promote the development of agricultural modernization.South China Agricultural University Engineering College developed a front axle swing steering hydraulic four-wheel drive chassis with flexible steering,steering radius and other characteristics,but also there are high-speed steering irregular,the minimum control angle of the larger problem.Front axle swing steer ing principle In the steering,the steering wheel to stop turning,turn the outer wheel to continue to rotate,thus driving the front axle swing,the chassis to achieve steering.Through the test analysis of the prototype,from the test curve can be seen in the high-speed steering of the chassis,the steering wheel oil pressure and flow will be a sudden change,which turned to the hydraulic motor pressure from 4.35 MPa down to 2.21 MPa,steering lateral hydraulic motor pressure from 4.26 MPa up to 7.29 MPa,continuous steering will occur when the strong hydraulic shock phenomenon is not conducive to the safety and stability of the chassis driving.In order to improve the ride speed and stability of the chassis,the hydraulic control system is improved.The two schemes are the installation of the traditional steering wheel to control the minimum steering angle of the front axle swing and the use of the walking wheel to drive the hydraulic motor back pressure to slow down the drive wheel to achieve minimum steering angle control.Through theoretical analysis and comparison,based on the simplicity and reliability of control,the use of back pressure control scheme is decided.Based on the requirements of chassis operation and walking,the dynamic design and selection and selection of the main components of the hydraulic steering system are made to improve the matching degree between the components,and the power source of the chassis is more efficient.In order to verify the feasibility of controlling the chassis steering by using the back pressure of the walking wheel drive motor,this paper uses the AMESim software to simulate the back pressure scheme.The AMESim simulation model is established by matching the parameters of each component.The simulation results sho w that the speed of the wheel on the inside of the steering wheel is gradually smaller and the rotational speed of the steering wheel without the back pressure increases,and the speed difference is formed on both sides.The chassis is deflected toward the inside of the steering back.The size of the steering radius is proportional to the size of the back pressure.In order to further study the relationship between the turning radius and the back pressure of the chassis,the bench test and the walking performance test of the front axle swing steering hydraulic four-wheel drive chassis prototype were carried out.The results of the bench test show that under the condition of zero loads,the running speed of the front wheel of the chassis can be controlled by the back pressure.The greater the back pressure,the smaller the inner wheel speed.The walking performance test includes the chassis steering performance test and the chassis linear performance test.C hassis steering performance test shows that: in different driving conditions,are the greater the back pressure,the smaller the radius of the steering;and back pressure caused by the pressure on both sides of the oil return range between 0MPa to 0.50 MPa,steering radius from infinity To turn in place.Chassis linear performance test shows that: front wheel front beam value of 10 mm,the chassis of the driving deflection rate of not more than 5%,the chassis in the cement flat road with a straight line driving ability.