In Axial Piston Pumps the piston are parallel to the axis of rotation of the shaft or slightly inclined at an angle of not more than 45 degrees. To pump fluid the pistons in the pump must move forward while the drive shaft rotates converting the rotational motion of the input shaft into the translational motion of the pistons is possible due to the inclined position of the bent axis or the swashplate on which they rest. In the first case the device is called a bent axis pump, In the second case – it is a swashplate pump.Axial piston pumps have several pistons that are arranged parallel to the drive shaft. They are available as either variable pumps or constant pumps.Variable displacement axial piston pumps adjust the geometric output volume from maximum to zero. As a result they vary the flow rate that is provided to the consumers.Fixed displacement axial piston pumps have a constant geometric displacement and convey a constant flow rate depending on the rotation speed.Axial piston pumps can contain most of the necessary circuit controls intrinsically by controlling the swash-plate angle, to regulate flow and pressure. They are very reliable and can allow the rest of the hydraulic system to which they’re attached to be very simple and inexpensive.They are used to power the hydraulic systems of jet aircrafts, being gear-driven off of the turbine engine’s main shaft, and are often used for automotive air conditioning compressors for cabin cooling. The design of these pumps meets the limited weight and space requirement in the vehicle’s engine bay and reduces vibrations.Pressure washers also use these pumps, and axial reciprocating motors are used to power many machines. They operate on the same principles as axial piston pumps, except that the circulating fluid is provided under substantial pressure and the piston housing rotates and provides shaft power to another machine. A typical use of an axial reciprocating motor is powering small earthmoving machines such as skid loader machines.
