Patent ID: 9395014
Filing Date: 2016-07-19
CPC Classification: F15B,F16K,H01F

Claim Text:
1. A pilot-control stage for a proportionally controlled high-pressure hydraulic valve comprising: a housing including a piston chamber; a guide piston mounted in the housing in an axially displaceable manner, the guide piston including a control piston mounted in the piston chamber in an axially displaceable manner and a tappet extending through the housing, so the tappet can be operatively connected to a following piston of the hydraulic valve; a compensating piston extending into a compensating chamber formed in the control piston, and an axially oriented tappet bore formed in the guide piston that extends from the compensating chamber to the free end of the tappet, the tappet bore to hydraulically connect the compensating chamber to the hydraulic valve, wherein the housing is configured as a pole tube at least in an area of the control piston, wherein an electromagnetic coil is disposed around the pole tube, wherein the control piston is configured as an electromagnetic armature, so the coil interacts with the control piston in such a manner when an electric current is applied onto the coil, the control piston and thus the tappet are axially moved and the piston chamber is sealed off from the high-pressure area of the hydraulic valve by a high-pressure seal between the compensating piston and the control piston and by a high-pressure seal between the tappet and the housing in such a manner the piston chamber is kept pressureless or in a low-pressure range, and wherein a displacement sensor is provided on the housing that interacts with a sheath coupled to the control piston, the displacement sensor to at least partially surround the sheath.