Radial piston machines

A hydraulic radial piston machine of the positive displacement type comprising a housing defining an internal chamber, a cylinder-barrel rotatable about an axis and disposed within said internal chamber and an annular track-ring having a self-aligning ability when loaded surrounding said cylinder-barrel, said cylinder-barrel being provided with a series of cylinders each containing a piston such that the pistons in said cylinders bear their loads on said track-ring, fluid distribution means in said housing comprising a pair of angularly spaced arcuate slots arranged to fluidly connect with said cylinders of said cylinder-barrel, abutment means in said housing including a first abutment surface comprising a concave first part-cylindrical bearing surface and a second abutment surface comprising a concave second part-cylindrical bearing surface, the first and second bearing surfaces being arranged to lie radially adjacent to a convex third bearing surface formed by said track-ring with sufficient radial clearance such that said pistons urge said third bearing surface to engage said first bearing surface and disengage from said second bearing surface or vice versa, depending on which one of said pair of arcuate slots is distributing fluid at a higher pressure, and wherein said first and said second abutment surfaces are angularly spaced within said housing to be substantially in phase with said arcuate slots.

A hydraulic radial piston machine of the positive displacement type comprising a housing defining an internal chamber, said housing being provided with one of more internal fluid-passages, a drive-shaft supported by at least one bearing in said housing and driving a cylinder-barrel rotatable about an axis and disposed within said internal chamber, a pintle-valve supported in said housing and extending into said internal chamber to support said cylinder barrel, an annular track-ring having a self-aligning ability when loaded surrounding said cylinder-barrel, said track-ring being eccentrically positioned with respect to said cylinder-barrel, said cylinder-barrel being provided with a series of cylinders each containing a piston such that the pistons bear their loads on said track-ring, a pair of arcuate-slots formed on the periphery of said pintle-valve and arranged to fluidly connect with said cylinders of said cylinder-barrel, abutment means in said housing and comprising first and second abutment-surfaces, said first and second abutment-surfaces being angularly spaced within said housing to be substantially in phase with said arcuate-slots and lying generally radially adjacent to said track ring, said track-ring being provided with a degree of radial freedom to move relative to the radial position of said cylinder-barrel such that said pistons urge said track ring to engage the first abutment surface and disengage the second abutment surface or vice versa, depending on whichever one of said pair of arcuate slots is subjected to the higher pressure.