Construction type of displacement pumps with multiple pistons, which, as in the radial piston pump, are arranged in a star shape around and perpendicular to the drive axis. They can be subjected to pressure from the inside or outside by pressure fluid and are, amongst other things, suitable for high constant pressures .
Pressurised from the inside (supported on the outside):
The cylinder block turns around a fixed pivot, which feeds the oil in and out via the valve ports (Figure R 4). The pistons receive their lifting impetus from an eccentric thrust ring on the outer diameter, which can be moved along a guided route. The output volume or geometric displacement can be changed continuously by moving the eccentric thrust ring. Movement beyond the zero position will reverse the flow rate direction (reversing pump).
Pressurised from the outside (supported on the inside):
The pistons in the fixed cylinder block are moved by an eccenter on the drive shaft. The hydraulic fluid flow is generally controlled by suction and pressure control valves (Figure R 5). Another concept works via inlets and valves on the pressure side.
![034ccc6692417e3296d824e0ffcb2372ebf12fd1 0001_radialkolbenpumpe.gif](/fileadmin/smc/files/034ccc6692417e3296d824e0ffcb2372ebf12fd1.gif)
Figure R 4: Radial piston pump pressurised from the inside
![1020091bfd0f5472cc6218a81c3a5d9a6dc48ba1 0002_radialkolbenpumpe.gif](/fileadmin/smc/files/1020091bfd0f5472cc6218a81c3a5d9a6dc48ba1.gif)
Figure R 5: Radial piston pump pressurised from the outside (valve-controlled)