Development of Tractor Three-point hitch Type Dynamometer(I) - Kinematic Analysis

摘要

The use of tractor and tractor implement are increasing due to the decline in rural labor force and aging population. Tractors are affected by various soil parameters such as soil physical properties and moisture content at work. The factors such as traction and PTO torque when working a tractor are important variables in tractor parts or tractor implement design. Therefore, it is need to develop a dynamometer system that can measure the tractor's traction and PTO torque. This study analyzed factorsthat change when three-point hitch type (Category-1) dynamometer is attached. The mechanism that changes due to dynamometer attachment is analyzed based on the ISO Standard. Angle of the upper and lower links of the tractor is calculated by the crank-locker equation. In addition, the cosine ratio of the PTO universal joint was calculated according to the link angle change. As a result of the analysis, the upper and lower link angles should be 61.66 and 28.27 degrees, in order to satisfy the prescribed transport height 820mm. For all conditions, the cosine ratio at the transport height was not able to meet the optimum. This study adjusted the values within the standard to obtain the suitable cosine ratio. In the future, we will design a dynamometer frame shape that does not cause interference with the universal joint and plan to structural analysis and material selection to ensure the reliability of the dynamometer frame. Also, the dynamometer will be verified through the static load test and field test.