Piston pump

Abstract

A piston pump with a piston in a pump chamber has, for controlling an inlet and an outlet of the pump chamber, in a partial region of its peripheral surface, a recess that can be aligned, by a rotational movement about its longitudinal axis, with the inlet or the outlet. By means of a stroke cam gear, the piston can be caused to carry out a lifting motion within the pump chamber. The stroke cam gear is formed by a peripheral guiding path of an adjusting element, which can be swiveled about a stationary axis of rotation, and a radial projection at the piston, which engages this guiding path.

What is claimed is:  
     
         1 . A piston pump comprising a piston in a pump chamber having an inlet and an outlet, said piston having, in a partial region of its peripheral surface, a recess that can be aligned by a rotational movement about its longitudinal axis with the inlet or outlet to thereby control the inlet and the outlet of the pump chamber, said piston pump further comprising a stroke cam gear to cause the piston to carry out a stroke motion within the pump chamber, wherein the stroke cam gear comprises an adjusting element which can be swiveled about a stationary axis of rotation and which comprises a peripheral guiding path and a radial projection at the piston which engages the guiding path.  
     
     
         2 . The piston pump of  claim 1 , wherein the projection comprises a pin with a sliding block protruding radially from the free end of the piston and the sliding block engages the guiding path of the adjusting element.  
     
     
         3 . The piston pump of  claim 2 , wherein the adjusting element is constructed as a plate which overlaps the piston with a borehole having the guiding path and, for forming the axis of rotation, has two pegs which are aligned at opposite sides with the guiding path and engage pivotably a base of the piston pump attached to the housing.  
     
     
         4 . The piston pump of  claim 3 , wherein the axis of rotation passes tangentially through the guiding path in the region of the point of application of the sliding block of the radial pin.  
     
     
         5 . The piston pump of  claim 1 , wherein the adjusting element is constructed as a plate, which overlaps the piston with a borehole having the guiding path and, for forming the axis of rotation, has two pegs, which are aligned at opposite sides with the guiding path and engage pivotably a base of the piston pump, attached to the housing.  
     
     
         6 . The piston pump of any one of claims  1 - 5 , wherein the adjusting element is constructed for swiveling out of a position, extending at right angles to the longitudinal axis of the piston into a tilted position, extending obliquely to the longitudinal axis of the piston.  
     
     
         7 . The piston pump of any one of claims  1 - 5 , wherein the sliding block is constructed as a roll body, which is mounted rotatably on the pin.