Patent ID: 7264455

Claim:
A rotary positive displacement hydraulic machine in the form of a gear pump or motor comprising a housing defining two mutually intersecting parallel working chambers having a low pressure inlet side and a high pressure outlet side, two meshing rotors mounted for rotation in the two chambers, respectively, and two bearing supports at opposite ends of the chambers and each supporting bearings in which the two rotors are journalled for rotation, wherein at least one end of the housing is closed by a separate end cover and wherein the or each separate end cover and an adjacent end of the housing each has at least one elongate recess on each of the two major sides of the working chambers, the recesses in the or each end cover being alignable with respective recesses in the adjacent end of the housing and there being at least one elongate keying element in each pair of aligned recesses so that the or each open end of the housing is supported against outward deflection by differential fluid pressure in the chambers in a direction transverse to a plane containing the axes of rotation of the meshing rotors.