Patents by Inventor Stefan Liehmann

Stefan Liehmann has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20240117853
    Abstract: A damping valve device for a vibration damper has a restriction in connection with a valve element movable from an open position into a restriction position depending on the flow velocity of a damping medium inside the restriction. The valve element, as a variable-diameter annular element, moves in closing direction with increasing flow velocity of the damping medium within an annular groove of a valve support. The annular groove is constructed as a pressure space having at least one inflow orifice and at least one outflow orifice. The valve element is positioned at a radial distance from an annular groove base by centering elements.
    Type: Application
    Filed: February 15, 2022
    Publication date: April 11, 2024
    Inventors: Jörg RÖSSELER, Aleksandar KNEZEVIC, Stefan LIEHMANN
  • Patent number: 10400845
    Abstract: A seal guide unit for guiding and sealing a piston rod of a vibration damper having a first guide element and a second guide element fixedly connected to the first guide element and arranged coaxial to the first guide element, and a radially moveable piston rod seal arrangement arranged coaxially between the two guide elements and is at least indirectly surrounded in circumferential direction by at least one guide element, including a defined radial annular gap, and comes in at least indirect axial contact with at least one guide element. The piston rod seal arrangement includes a piston rod seal and a sliding element which encloses the piston rod seal in circumferential direction and axially limits the piston rod seal at least on one side. The sliding element has a lower friction coefficient than parts of the seal guide unit adjoin the piston rod seal arrangement.
    Type: Grant
    Filed: October 12, 2015
    Date of Patent: September 3, 2019
    Assignee: ZF Friedrichshafen AG
    Inventors: Thomas Thein, Stefan Liehmann, Wolfgang Breun, Alexander Pass, Michael Heinisch, Ingo Schau, Uwe Gehringer
  • Publication number: 20170328437
    Abstract: A seal guide unit for guiding and sealing a piston rod of a vibration damper having a first guide element and a second guide element fixedly connected to the first guide element and arranged coaxial to the first guide element, and a radially moveable piston rod seal arrangement arranged coaxially between the two guide elements and is at least indirectly surrounded in circumferential direction by at least one guide element, including a defined radial annular gap, and comes in at least indirect axial contact with at least one guide element. The piston rod seal arrangement includes a piston rod seal and a sliding element which encloses the piston rod seal in circumferential direction and axially limits the piston rod seal at least on one side. The sliding element has a lower friction coefficient than parts of the seal guide unit adjoin the piston rod seal arrangement.
    Type: Application
    Filed: October 12, 2015
    Publication date: November 16, 2017
    Inventors: Thomas THEIN, Stefan LIEHMANN, Wolfgang BREUN, Alexander PASS, Michael HEINISCH, Ingo SCHAU, Uwe GEHRINGER
  • Patent number: 9261159
    Abstract: A piston-cylinder unit for a mono-tube damper, includes: a cylinder having an inner wall and a closure fixed axially with respect to the cylinder by positive engagement with one or more impressions of the inner wall, the closure having a plug sealed with respect to the inner wall, the plug having a reinforced portion and being axially moveable with respect to the cylinder when a temperature threshold is exceeded. Axial movement caused by the temperature threshold being exceeded causes deformation of the plug with respect to the cylinder so as to: (i) form a channel between the plug and the inner wall of the cylinder, through which pressure, caused by the increased temperature, can escape the piston-cylinder unit, and (ii) permit axial movement of the closure only to a point at which the reinforced portion of the plug comes into contact with the one or more impressions in the cylinder.
    Type: Grant
    Filed: December 11, 2013
    Date of Patent: February 16, 2016
    Assignee: ZF Friedrichshafen AG
    Inventors: Thomas Thein, Stefan Liehmann, Ingo Schau, Michael Heinisch
  • Publication number: 20150159723
    Abstract: A piston-cylinder unit for a mono-tube damper, includes: a cylinder having an inner wall and a closure fixed axially with respect to the cylinder by positive engagement with one or more impressions of the inner wall, the closure having a plug sealed with respect to the inner wall, the plug having a reinforced portion and being axially moveable with respect to the cylinder when a temperature threshold is exceeded. Axial movement caused by the temperature threshold being exceeded causes deformation of the plug with respect to the cylinder so as to: (i) form a channel between the plug and the inner wall of the cylinder, through which pressure, caused by the increased temperature, can escape the piston-cylinder unit, and (ii) permit axial movement of the closure only to a point at which the reinforced portion of the plug comes into contact with the one or more impressions in the cylinder.
    Type: Application
    Filed: December 11, 2013
    Publication date: June 11, 2015
    Inventors: Thomas Thein, Stefan Liehmann, Ingo Schau, Michael Heinisch