Development of the Reliability Assessment Process of the Hydraulic Pump for a 78 kW Tractor during Major Agricultural Operations

This study focuses on the development of the reliability test method for the hydraulic pump of a tractor during major agricultural operations (plow, rotary, baler, and wrapping) at various driving and PTO (power take-off) gear stages. The hydraulic-pressure-measurement system was installed on the tractor. The measured hydraulic pressure and engine rotational speed were converted to the equivalent pressure and engine speed for each agricultural operation using a mathematical formula. Additionally, the overall equivalent pressure and overall engine speed were calculated to determine the acceleration lifetime. The average equivalent pressure and engine speed for plow tillage were calculated at around 5.44 MPa and 1548.37 rpm, respectively, whereas the average equivalent pressure and engine speed for rotary tillage were almost 5.70 MPa and 2074.73 rpm, accordingly. In the case of baler and wrapping operations, the average equivalent pressure and engine speed were approximately 11.22 MPa and 2203.01 rpm, and 11.86 MPa and 913.76 rpm, respectively. The overall hydraulic pressure of the pump and the engine rotational speed were found to be around 10.07 MPa and 1512.93 rpm, respectively. The acceleration factor was calculated using the overall pressure and engine speed accounting for 336. In summary, the developed reliability test method was evaluated by RS-B-0063, which is the existing reliability evaluation standard for agricultural hydraulic gear pumps. The evaluation results proved that the developed reliability test method for the hydraulic pump of a tractor satisfied the standard criteria. Therefore, it could be said that the developed reliability test method could be applicable to the hydraulic pump of the tractor during agricultural field operations.