The invention relates to a cylinder piston arrangement for an especially volumetric fluid pump or a fluid motor, preferably comprising at least one axial expansion tubular membrane piston defining at least one inner pulsating working chamber. A particular field of application for such pumps or motors is the operation thereof with fluids loaded with extraneous materials, especially abrasive granulated materials. Especially high-speed machines with high working pressures of between a few hundred to a thousand bar are required, the energetic and also volumetric degree of efficiency thus becoming highly important factors. The aim of the invention is therefore to create pumps or fluid motors which are characterized by high degrees of efficiency and long service lives. To this end, at least one clearance driving body (TK1) is actively connected to the pulsating working chamber (AR).