Piston rod seal

Abstract

A controllable coolant pump of internal combustion engines, including a pump housing, a drivable pump shaft rotatably in the pump housing, an impeller fixed on a free end of the pump shaft, and a pressure-difference-driven actuator to drive at least one piston rod guided in a piston rod bore of the pump housing, which includes a control spool at the impeller-side end of the piston rod, and which is guided in the piston rod bore by a guide bushing which is a portion of a sealing device which seals off a pump space carrying coolant with respect to the pressure-difference-driven actuator. The sealing device includes two seals which are spaced apart from one another, are on one end of the guide bushing, and include a static sealing area surrounding the guide bushing on the circumferential side and a dynamic sealing area adjoining the static sealing area.

1 - 10 . (canceled) 
     
     
         11 . A controllable coolant pump of internal combustion engines, the controllable coolant pump omprising:
 a pump housing;   a drivable pump shaft rotatably mounted in the pump housing;   an impeller non-rotatably fixed on a free end of the pump shaft; and   a pressure-difference-driven actuator to drive at least one piston rod which is guided in a piston rod bore of the pump housing and including a control spool valve held at an impeller-side end of the piston rod; wherein   the control spool is set up to variably cover an outflow region of the impeller;   the piston rod is guided in the piston rod bore by a guide bushing which is a portion of a sealing device which seals off a pump chamber carrying coolant from the pressure-difference-driven actuator;   the sealing device includes two seals which are each on one end of the guide bushing and which each include a static sealing area circumferentially surrounding the guide bushing and a dynamic sealing area adjoining the static sealing area, a first seal to seal a pressure chamber of the pressure-differential-driven actuator at an end of the guide bushing remote from the impeller, and a second seal to seal the pump chamber carrying coolant at the end of the guide bushing adjacent to the impeller; and   the dynamic sealing area of the first seal extends into an interior of the guide bushing from an end surface at the end remote from the impeller, the dynamic sealing area of the first seal tapering inwards into the guide bushing in an axial direction.   
     
     
         12 . The controllable coolant pump according to  claim 11 , wherein the dynamic sealing area of the first seal is spaced from an inner side of the guide bushing in an unloaded state. 
     
     
         13 . The controllable coolant pump according to  claim 11 , wherein an outside of the static sealing area of the first seal sealingly abuts an inside of the piston rod bore. 
     
     
         14 . The controllable coolant pump according to  claim 11 , wherein the static sealing area of the first seal includes an annular protrusion adjacent to an end surface of the sealing device. 
     
     
         15 . The controllable coolant pump according to  claim 11 , wherein the dynamic sealing area of the second seal extends from an end surface of the guide bushing adjacent to the impeller into the pump chamber and lies outside the guide bushing. 
     
     
         16 . The controllable coolant pump according to  claim 11 , wherein an outer side of the static sealing area of the second seal bears against an inner side of the piston rod bore in a sealing manner, and the dynamic sealing area of the second seal tapers in a conical region on an outer side thereof away from the guide bush at an end thereof on an impeller side. 
     
     
         17 . The controllable coolant pump according to  claim 11 , wherein the second seal is slidable onto the guide bushing and engageable with at least one annular groove of the guide bushing to fix the position. 
     
     
         18 . The controllable coolant pump according to  claim 11 , wherein a drainage outlet is between the two seals in the guide bushing. 
     
     
         19 . The controllable coolant pump according to  claim 11 , wherein the dynamic sealing areas include sealing lips. 
     
     
         20 . The controllable coolant pump according to  claim 11 , wherein the seals at least partially surround the guide bushing on the end surface.