MULTISTAGE GEAR SHIFTING DEVICE FOR HYDRAULIC MOTOR

PROBLEM TO BE SOLVED: To obtain hydraulic-motor output at a multistage and high gear ratio such as 1:2:3 or 1:2:4 by universal hydraulic motors and hydraulic circuits. SOLUTION: Three or more hydraulic motors M having the same capacity are connected to an output shaft at the same reduction gear ratio. When a control switching valve e is neutral, switching valves a, b, and c are neutral while the hydraulic motors M1, M2, M3, and M4 are connected in series. When the control switching valve e is switched to the 2ND position, the switching valve b is switched to a normal rotation direction and an oil amount Q is sent to the hydraulic motor M1 and the hydraulic motor M3. Every two hydraulic motors are connected in parallel thereby. Output is set such that the rotational frequency is Q/2/V and the torque is equivalent to an amount of two hydraulic motors. When the control switching valve e is switched to the LOW position, all the switching valves a, b, and c are switched and all the hydraulic motors M1, M2, M3, and M4 are piped in parallel. Output is set such that the rotational frequency is Q/4/V and the torque is equivalent to a total amount of four hydraulic motors. COPYRIGHT: (C)2009,JPO&INPIT