摘要:
The present invention relates to a speed changing device for a hydraulic driving apparatus and a speed change control method thereof which provide excellent controllability, running efficiency and reliability without occurrence of cavitation. To this end, the device comprises a shifter selected position sensor (63a) for detecting a shift lever change, a motor rotation speed sensor (52) for detecting a rotation speed of a hydraulic motor (50), and a control device (60), and the control device (60) judges and controls either a powering control or a brake control based on the change of the shift lever selection and on the comparison of the detected motor rotation speed with a memorized motor rotation speed. In addition, a two-stage back pressure valve (23) may be provided between a directional control valve (21) and an oil tank.
摘要:
A method of controlling speed change of a hydraulic drive device for vehicles and a speed change device, which provide a favorable travelling efficiency and a favorable controllability. The method of controlling speed change comprises performing control through discriminating at least between power running and brake running from a magnitude of acceleration (θ) and a rotating speed of a hydraulic motor (50). At the time of power running, a change-over valve (21) may be fully opened in accordance with the rotating speed (ωout) of the hydraulic motor (50) and the magnitude of acceleration (θ). Also, the speed change device comprises a detecting sensor (61a) for the magnitude of acceleration, a motor rotating speed detecting sensor (52) for detecting a vehicle speed (V), and a control device (60) for discriminating between power running and brake running on the basis of the magnitude of acceleration (ωout) and the vehicle speed (V) for controlling.