Radial piston pump with improved efficiency for high pressure fuel supply in injection systems of internal combustion engines

The pump has three cylinders (17) set in the housing (23) 120 degrees apart. Each piston has a hemispherical inner end (59) engaging a shoe which engages on a triangular ring (31) on an eccentric shaft. Two galleries (51a,51b) connect the working ends of two cylinders. The first has a side branch leading to a magnetic control valve (15) which releases fuel back to the inlet via a reservoir. The second is connected to a relief valve (55).