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1. (WO2017153223) HYDRAULIC STEERING DEVICE WITH ENHANCED FAULT PREVENTION

Pub. No.:    WO/2017/153223    International Application No.:    PCT/EP2017/054772
Publication Date: Fri Sep 15 01:59:59 CEST 2017 International Filing Date: Thu Mar 02 00:59:59 CET 2017
IPC: B62D 5/09
Applicants: HYDRAULIK NORD FLUIDTECHNIK GMBH & CO. KG
Inventors: BERGMANN, Erhard
KÄCKENMEISTER, Toralf
DE LA MOTTE, Markus
Title: HYDRAULIC STEERING DEVICE WITH ENHANCED FAULT PREVENTION
Abstract:
The invention relates to a hydraulic steering device (10) which hydraulically connects a steering cylinder (12) to a supply system (14), wherein the supply system (14) is hydraulically operatively connectable to the steering cylinder (12) via a steering assembly (16) for the purposes of forming a main flow connection (22), and the supply system (14) is furthermore hydraulically operatively connectable to the steering cylinder (12) via a flow regulating valve arrangement (24), such that a secondary flow connection (26) can be formed which bypasses the main flow connection (22) and via which at least one first working chamber (28) and one second working chamber (30) of the steering cylinder (12) can be supplied independently of one another with hydraulic fluid, and wherein the flow regulating valve arrangement (24) comprises multiple independently actuable valves (32, 34, 36, 38, 61, 63, 68, 70) by means of which at least a first feed (40) and a first return (42) for the first working chamber (28) and a second feed (44) and a second return (46) for the second working chamber (30) can be adjusted, and wherein the hydraulic steering device (10) furthermore comprises at least one shut-off valve (48, 66) for shutting off the secondary flow connection (26) at least in sections and furthermore comprises at least one electrical control unit (50) which is designed to output actuation currents for one or more valves (32, 34, 36, 38, 61, 63, 68, 70). It is provided that the hydraulic steering device (10) comprises means (56) for measuring and for comparing at least two actuation currents, and the means (56) are furthermore designed to move at least the shut-off valve (48, 66) into a shut-off position in the presence of a deviation of compared actuation currents. The subject matter of the invention also encompasses a method for safeguarding the hydraulic steering device (10).