The piston motor is a swash plate piston motor
The structure of the Sumitomo excavator piston motor is shown in Figure 3-59
Figure 3-59 Structure of a piston motor
Nine pistons are installed on the cylinder block, the end face of the cylinder block is in contact with the valve plate, and two cylindrical ports B and C are installed on the valve plate. The hydraulic oil discharged from the hydraulic pump flows in from the P1 or P2 port, and when the piston motor is running, the hydraulic oil flows out from the P2 port or the P1 port.
In addition, the hydraulic oil flowing from the sliding part and the gap into the housing returns to the hydraulic oil tank from the T1 or T2 port of the bottom plate
① The high-pressure hydraulic oil flowing out from the P port enters the cylindrical B port on the valve plate, the piston is pressurized, and the upper part of the swash plate rotates and moves from top dead center to bottom dead center.
② The P2 port side becomes low pressure, the piston moves from bottom dead center to top dead center, and the hydraulic oil passes through the cylindrical C port on the valve plate and is discharged into the P2 port
③ With the reciprocating motion of the piston, the cylinder and the shaft combined with the spline rotate counterclockwise as shown by the arrow in the figure.
④ When the piston motor rotates clockwise, the port side becomes low pressure and the P2 port side becomes high pressure.
From this, the piston motor can convert the liquid energy of the hydraulic oil transmitted by the hydraulic pump into mechanical energy, and then output with high-speed, low-torque power. In addition, the torque and speed of the piston motor are determined by the pressure and flow. Therefore, as the pressure and flow increase, the torque and speed of the piston motor will also increase.
