Direct drive variable displacement pumps that provide variable displacement wherein a swashplate pivots and changes the angle position in the direct drive variable displacement pumps. The swashplate is also capable of changing the stroke length of pistons in such direct drive variable displacement pumps and rotation of a rotating shaft is converted into axial or radial movement. In direct drive variable displacement pumps in accordance with the present invention, plungers and their respective plunger housings do not rotate relative to the rotating shaft while the swashplate rotates with rotating shaft. In addition, hydraulic control pistons are preferably used to change the angle of the swashplate and these hydraulic control pistons rotate with the rotating shaft. A first preferred embodiment of a direct drive variable displacement pump disclosed herein is an axial displacement type direct drive variable displacement pump while a second preferred embodiment of a direct drive variable displacement pump disclosed herein is a radial type direct drive variable displacement pump.
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