Hydraulic power steering system with dual, double-acting piston-cylinder units

• US 6,047,788 A
• Filed: 07/03/1997
• Issued: 04/11/2000
• Est. Priority Date: 07/11/1996
• Status: Expired due to Fees

• Current Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Original Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Inventors: Moser, Martin, Bohner, Hubert
• Primary Examiner(s): Swann, J. J.
• Assistant Examiner(s): Ririe, Andrew J.
• Application Number:
  US08/887,834
• Time in Patent Office: 1,013 Days
• Field of Search: 180/406, 92/151, 92/152, 92/110, 92/255, 92/258
• US Class Current: 180/406
• CPC Class Codes: B62D 5/12 Piston and cylinder
• CPC Class Codes: F15B 11/0365 Tandem constructions
• CPC Class Codes: F15B 2211/20538 constant capacity
• CPC Class Codes: F15B 2211/3116 the pump port being open in the centre position, e.g. so-called open centre
• CPC Class Codes: F15B 2211/3127 Floating position connecting the working ports and the return line
• CPC Class Codes: F15B 2211/3144 the positions being continuously variable, e.g. as realised by proportional valves
• CPC Class Codes: F15B 2211/327 electrically or electronically
• CPC Class Codes: F15B 2211/6336 representing a state of the output member, e.g. position, speed or acceleration
• CPC Class Codes: F15B 2211/6346 representing a state of input means, e.g. joystick position
• CPC Class Codes: F15B 2211/7056 Tandem cylinders
• CPC Class Codes: F15B 2211/8757 using redundant components or assemblies

Abstract

In a hydraulically operated steering for a motor vehicle comprising a control motor with first and second double acting piston and cylinder units arranged in axial alignment and a single piston rod extending through the first and second double acting piston and cylinder units, at least one of the double acting piston and cylinder units includes an annular piston which is fastened on the pistons rod in a predetermined axial position and an annular divider wall is disposed between the pistons for slidably supporting the piston rod and separating the cylinders of said first and second double acting piston and cylinder units fluidically from one another so as to form cylinder chambers for said pistons limited at one side by an annular divider wall and by guide sleeve members disposed in the opposite ends of the cylinder units.

Claims

1. A hydraulically operated steering for a motor vehicle comprising a control motor including a first double acting piston and cylinder unit and a second double acting piston and cylinder unit arranged in axial alignment with, and adjacent to, said first double acting piston and cylinder unit, a single piston rod extending through said first and second double acting piston and cylinder units, at least one of said double acting piston and cylinder units having an annular piston disposed on said piston rod and being fastened thereto in a predetermined axial position, said first and second piston and cylinder units including a divider wall ring disposed between said two double acting pistons and having a central opening slidably receiving said piston rod so as to separate said first and second double acting piston and cylinder units fluidically from one another, said piston and cylinder units including cylinder tubes which overlap each other in the area around said divider wall ring and are firmly joined in the area of said divider wall ring and which have opposite outer ends with guide sleeve members providing, together with said divider wall ring, sealed cylinder chambers and forming support bearing structures for axially slidably supporting said piston rod.

2. A steering according to claim 1, wherein at least said annular piston of said one double acting piston and cylinder unit has at its inner circumference at least one axially extending flange and said piston rod has an annular groove into which said annular flange is pressed for firm engagement of said annular piston with said piston rod.

3. A steering according to claim 1, wherein one of said cylinders has an end portion adjacent said other cylinder which has a diameter larger than that of the adjacent end portion of the other cylinder and receives the end portion of said other cylinder, said other cylinder end portion having a circumferential groove into which a portion of the end portion of said one cylinder is pressed for firm engagement therewith.

4. A steering according to claim 1, wherein boots are provided at the opposite ends of said piston cylinder units and said piston rod has an axial bore extending therethrough and providing communication between the spaces enclosed by said boots.