Passive radial mechanism of a bogie with the auxiliary steering device for the straddle monorail vehicle

The dynamic performance of the vehicle is improved when the bogie of a monorail vehicle passes through the curve in the radial position. This study aimed to derive the analytical relationship between the torque generated by the auxiliary guiding device and the yaw angle between the bogie and the vehicle body based on the geometric relationship between the auxiliary guiding device of the straddle monorail and the mechanical characteristics of the hydropneumatic spring. The main influencing factors were the angle of the arm and the initial pre-pressure of the hydropneumatic spring. Theoretical analysis and model simulation showed that the output torque of the auxiliary steering device had a linear relationship with the pre-pressure of the hydropneumatic spring, but a complex relationship with the angle of the rotating arm. When the reasonable pre-pressure (12.4 kN) of the hydraulic spring was selected, the output torque of the auxiliary steering device could be offset against the moment generated by the secondary suspension. At this time, the yaw angle of the running part was close to zero, and the bogie could be placed in the radial position on the circular curve, thus effectively reducing the wear of the running wheel and guiding wheel.