Abstract: The invention relates to a pump that has a housing with a recess in which a pump unit is situated. The pump unit has a pump chamber formed from a pump chamber ring and at least one pressure plate situated on the pump chamber ring, and a rotary-drivable pump element situated in the pump chamber. The pump unit has a pressure space which is delimited by the recess and the pressure plate. The invention provides that a circumferential distancing means is situated between the bearing surfaces of the pump chamber ring and the pressure plate on the pressure space side, or the radial extension of the pump chamber ring is chosen to be less than the radial extension of the pressure plate on the pressure space side.