Reciprocating-piston pump with plain bearing traversed by flow

摘要

A reciprocating-piston pump with plain bearing traversed by flow. The reciprocating-piston pump is driven by an electromagnet to have a bearing of the piston in a cylinder, which bearing is protected against local overheating and from which bearing decomposition and reaction products and any wear products generated are discharged. For this purpose, elongate helical depressions are provided in one of two bearing surfaces in a bearing gap between the piston and the cylinder, which depressions are traversed entirely or partially by a flow of the liquid which is delivered by the piston acting in interaction with other components of the reciprocating-piston pump for the delivery rate of the reciprocating-piston pump. Reciprocating-piston pumps of the described type can be used as dosing pumps and as delivery pumps in fuel-operated standstill heaters, auxiliary heaters and exhaust-gas purification systems in vehicles.

主权项

1. An electromagnetically driven reciprocating-piston pump comprising:
a piston which displaces fluid and which supports an armature piston of an electromagnet and which, is sealingly borne in a cylinder; and one or more depressions defined in at least one of two bearing surfaces in a bearing gap between the piston and the cylinder, wherein each depression extends over a part of a length of the piston or of the cylinder and wherein the depressions are of helical form to cover a part of the bearing surface, and wherein the depressions are connected via a low-resistance fluidic connection, by a transverse bore, to a valve and are connected via a further low-resistance fluidic connection to an armature chamber and are traversed at least partially by a flow of the fluid which is delivered by the piston acting in interaction with the cylinder for an output rate of the reciprocating-piston pump, wherein the delivery flow of the reciprocating-piston pump is conducted entirely through the transverse bore adjacent to the valve to depressions in the surface of the piston or of the cylinder, then through a second transverse bore into a longitudinal bore in the piston, and then through a third transverse bore adjacent to and into the armature chamber, wherein the depressions do not extend into the armature chamber and do not extend into a displacement body chamber.