VDP SERIES VARIABLE DISPLACEMENT HYDRAULIC PISTON PUMP:
VDP pumps are variable displacement axial piston pumps designed to use in open circuits. They are available from 40 to 120 cm3/rev and with a maximum pressure of 450 bar. They can be assembled directly into the PTO´s with support. They come standard with 1 1/4″ DIN shaft and BSP threaded ports for high pressure applications.
APPLICATIONS: Combined with any of our wide range of PE series eaton fuller PTO, PIM series Volvo I-Shift/Mack mDrive PTO, PA series hot shift PTO for AISIN and ALLISON automatic transmissions, PDT series PTO for the Detroit DT12, it can power your PTO hydraulic pumps wet kit or equipment on high pressure application such as truck mounted hydraulic cranes.
Variable Displacement Piston Pumps
A common variable displacement pump used in vehicle technology is the axial piston pump. This pump has several pistons in cylinders arranged parallel to each other and rotating around a central shaft. A swashplate at one end is connected to the pistons. As the pistons rotate, the angle of the plate causes them to move in and out of their cylinders. A rotary valve at the opposite end from the swashplate alternately connects each cylinder to the fluid supply and delivery lines. By changing the angle of the swashplate, the stroke of the pistons can be varied continuously. If the swashplate is perpendicular to the axis of rotation, no fluid will flow. If it is at a sharp angle, a large volume of fluid will be pumped. Some pumps allow the swashplate to be moved in both directions from the zero position, pumping fluid in either direction without reversing the rotation of the pump.
An efficient variation is the bent axis pump. Bending the axis reduces side loads on the pistons.
Piston pumps can be made variable-displacement by inserting springs inline with the pistons. The displacement is not positively controlled, but decreases as back-pressure increases.
Another variation is the variable displacement vane pump.