Robert Boschgmbh

Hans Feeser

Wolfgang Schuller

Rolf Hummel

Erwin Sinnl

Guenter Krenz

Michael Klose

The invention seeks to reduce structure-borne sound emissions of the reciprocating piston pump. The reciprocating pump is includes an outlet valve, which has a valve seat and a valve closing body that is received in a hollow space and is loaded by a closing spring. One outlet bore radially originates at the circumferential region of the valve seat and branches off from the hollow space. The opening of the outlet bore toward the hollow space extends at least approximately between the valve seat and the end toward the closing spring of the gap of least cross section, which is formed between the valve closing body and the inside circumference of the hollow space. As a result, a slowed opening motion of the valve closing element is attained, in which opening motion an opening gap opens up that has its largest flow cross section in the region of the outlet bore. The supply flow, which increases slowly as the outlet valve opens, results in a slowed force variation speed in the drive train of the reciprocating piston pump and a reduced emission of structure-borne sound. The pressure fluid pumping device may be used for instance in hydraulic motor vehicle brake systems having an anti-skid system and/or traction control system.

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Vaihingen/Enz-Aurich, Germany

Hans Feeser