Helical gear fluid machine

Claim 1

A helical gear fluid machine comprising, in combination: a fixed shaft; a fixed outer casing, having a first drive shaft end and a second end, opposite said first drive shaft end; an outer rotary element having a female helical gear form of n starts; means supporting said outer rotary element for rotation about a first fixed axis defined by said fixed outer casing; an inner rotary element having a male helical gear form of n±1 starts, said inner rotary element being rotatable within the outer rotary element about a second, fixed axis, said second axis being spaced apart from and substantially parallel to the first axis, the inner rotary element being only supported for rotation by means of the outer rotary element and by means of coupling with the drive shaft; said outer rotary element comprising: an elastomeric material body in which said female helical gear form is provided; a surrounding tubular metal barrel, said outer rotary element having axial ends; and two bearing zones on said tubular metal barrel, one at each axial end of said outer rotary element, said bearing zones being axially spaced from one another; an elastomeric material bearing member positioned between said bearing zones of said tubular metal barrel and said outer casing, effective to provide a radial bearing for said outer rotary element; an annular radially extending bearing surface on said bearing zone at the first, drive shaft end of said outer casing; and an axially resiliently mounted axial annular thrust bearing mounted to said outer casing and engaging said annular radially extending bearing surface.