Hydraulic steering system for vehicles

• US 5,215,158 A
• Filed: 09/30/1991
• Issued: 06/01/1993
• Est. Priority Date: 10/09/1990
• Status: Expired due to Fees

• Current Assignee: Danfoss A/S
• Original Assignee: Danfoss A/S
• Inventors: Pedersen, Harry E.
• Primary Examiner(s): HILL, MITCHELL
• Application Number:
  US07/767,473
• Time in Patent Office: 610 Days
• Field of Search: 180/132, 180/141, 180/142, 180/143, 60/387, 60/422
• US Class Current: 180/403
• CPC Class Codes: B62D 5/093 Telemotor driven by steering wheel movement hydraulic steering gear B62D3/14

Abstract

The steering system of a motor vehicle includes a two chamber steering motor having the application of pressurized fluid applied thereto through change over valves in one position by the way of a by pass valve and alternately in a second position by the way of a steering unit. The change over valves are operated from their first position to their second position upon activation of the steering unit which results in control valve moving from a position applying pressurized fluid from a pump to the by pass valve to a position applying pressurized fluid from the pump to the steering unit.

Claims

1. A hydraulic steering system for vehicles, comprising,

a pump and a tank,

a steering motor for operating a vehicle steering mechanism which motor has complementary first and second motor chambers,

a steering unit having left, right and neutral positions and a steering element for selecting said positions,

a load pressure line for said steering unit being pressurized only when said steering unit is in its neutral position, said steering unit being connected during normal operation via pump and tank lines respectively to said pump and said tank and via first and second motor lines to said first and second motor chambers,

bypass directional valve means having left, right and neutral positions for effecting quicker than normal steering movements being connected during a bypass mode operation via pump and tank lines respectively to said pump and said tank and via first and second motor lines to said first and second motor chambers,

a setting control element for moving said bypass directional valve means from a neutral position to either a desired left or a desired right turning position,

priority valve means connected to said load pressure line having a first mode position during turns when said load pressure line is not pressurized and a second mode bypass position when said steering unit is in a neutral position and said pressure line is pressurized, said priority valve means being operable during said first mode to connect said pump to said steering unit and operable during said second mode to connect said pump to said bypass valve unit,

selection valve means having normal and bypass operating positions for respectively connecting said steering unit motor lines and said bypass unit motor lines to said first and second motor chambers,

and check valve means connecting said selection valve means to said bypass unit motor lines to effect moving said selection valve means to said bypass operating position when either of said bypass unit motor lines is pressurized.