Patent ID: 8365651
Filing Date: 2013-02-05
Classification: F15B

Abstract:
1. A piston accumulator, comprising: an accumulator housing forming a cylindrical tube of magnetizable material and defining an axial direction along a longitudinal axis thereof, said housing having a gas space and a hydraulic fluid space; a piston axially movable along a stroke path in said cylindrical tube and forming a movable separating element separating said spaces in said housing, said piston having radially smaller and larger circumferential sections spaced from and engaging said cylindrical tube, respectively, and having a radially extending shoulder surface extending between said smaller and larger circumferential sections, said smaller circumferential section located on an end of said piston opening on said gas space, said larger circumferential section defining an opposite end of said piston facing said fluid space; a magnet arrangement mounted on and about said smaller circumferential section of said piston and generating a field on said cylindrical tube, said magnet arrangement including first and second annular rings of magnetizable material and a plurality of magnet elements with pole end surfaces between said annular rings with said pole end surfaces abutting said annular rings, said second annular ring being supported on said shoulder surface to support said magnet arrangement in a direction of said hydraulic fluid space; and a magnet field sensor positioned in an exterior of said cylindrical tube and including a first Hall sensor generating signals representative of piston positions along said stroke path in response to said field generated by said magnet elements.