# US 10,870,445 B2 · Hydraulic steering system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,870,445 B2 - Document ID: US10870445B2 - Status: Granted - Kind: B2 - Application number: 16/053,180 - Filed: 2018-08-02 - Published: 2019-02-07 - Granted: 2020-12-22 - Earliest claimed: 2017-08-02 - Assignees: Jungheinrich Aktiengesellschaft - Applicants: Jungheinrich Aktiengesellschaft - Inventors: René Bernau; Rainer Sedlmaier - Web page: https://patentgrep.com/patent/US10870445B2 ## CPC - B62D 5/09: characterised by means for actuating valves - B62D 5/06: fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle - B62D 5/10: characterised by type of power unit - B62D 5/30: Safety devices, e.g. alternate emergency power supply or transmission means to ensure steering upon failure of the primary steering means - B62D 5/32: for telemotor systems - B62D 15/021: {Determination of steering angle} - B66F 9/07568: {Steering arrangements} - B66F 9/22: Hydraulic devices or systems - B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M) - B66F: HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD ({invalid lifting devices A61G7/10; } mounting artificial islands on piles or like supports E02B17/00; scaffolding combined with lifting devices E04G1/22; lifting devices for sliding forms E04G11/24; lifting of buildings E04G23/06; shores or struts E04G25/00; lifts or other hoisting devices on ladders E06C7/12; props for mining E21D15/00) ## Abstract The present invention relates to a hydraulic steering system for a vehicle, in particular an industrial truck, comprising: a steering cylinder having two chambers and a hydraulic connection at each of the two chambers for activating a steering movement of at least one wheel of the vehicle; at least one hydraulic pump; at least one hydraulic tank for receiving hydraulic oil; and a steering block which comprises: two first hydraulic connections for connecting to the two hydraulic connections of the steering cylinder; at least two second hydraulic connections for supplying hydraulic oil from the hydraulic pump to the steering block and feeding the hydraulic oil back into the hydraulic tank; and a controllable valve assembly which receives control signals from a steering angle detection device and is designed to convey hydraulic oil to the steering cylinder on the basis of said control signals; the controllable valve assembly being further designed to be shiftable into at least one neutral position in which it allows a flow of hydraulic oil between the two chambers of the steering cylinder. The hydraulic steering system further comprises a pump device which is designed to stimulate the flow of hydraulic oil between the two chambers of the steering cylinder when the valve assembly is in the neutral position. ## Claims ### Claim 1 Hydraulic steering system for a vehicle comprising: a steering cylinder having two chambers and a hydraulic connection at each of the two chambers for activating a steering movement of at least one wheel of the vehicle; at least one hydraulic pump; at least one hydraulic tank for receiving hydraulic oil; a steering block which comprises: two first hydraulic connections for connecting to the two hydraulic connections of the steering cylinder; at least two second hydraulic connections for supplying hydraulic oil from the hydraulic pump to the steering block and feeding the hydraulic oil back into the hydraulic tank; and a controllable valve assembly which receives control signals from a steering angle detection device and is designed to convey hydraulic oil to the steering cylinder on the basis of said control signals, wherein the controllable valve assembly is further designed to be shiftable into at least one neutral position in which it allows a flow of hydraulic oil between the two chambers of the steering cylinder; and a pump device which is designed to stimulate the flow of hydraulic oil between the two chambers of the steering cylinder when the valve assembly is in the neutral position, wherein the pump device is integral with the steering block. ### Claim 2 (depends on 1) Hydraulic steering system according to claim 1, further comprising a priority valve which is designed to ensure an adequate supply of hydraulic oil to the steering block in comparison with other loads. ### Claim 3 (depends on 1) Hydraulic steering system according to claim 1, wherein the pump device is manually operable. ### Claim 4 (depends on 1) Hydraulic steering system according to claim 1, wherein the pump device has a stroke volume of approximately 7-8 cm3. ### Claim 5 (depends on 1) Hydraulic steering system according to claim 1, wherein the valve assembly comprises a manual shifting means for shifting into the at least one neutral position. ### Claim 6 (depends on 1) Hydraulic steering system according to claim 1, wherein the valve assembly can be shifted into two neutral positions which in each case allow one of the two directions of flow of hydraulic oil from one of the chambers of the steering cylinder into the other. ### Claim 7 (depends on 1) Hydraulic steering system according to claim 1, further comprising at least one shock valve in each of the connections of the steering block to the steering cylinder, which valve is designed to prevent the steering cylinder from being damaged by overloading. ### Claim 8 (depends on 1) Hydraulic steering system according claim 1, further comprising at least one pressure control valve. ### Claim 9 A vehicle comprising: at least one steerable wheel; at least one steering angle detection device which detects at least one of a steering direction or a steering speed of a steering device that is operable by a driver of the vehicle and which outputs control signals; and a hydraulic steering system which receives the control signals from the steering angle detection device and is arranged so as to activate a steering movement of the at least one steerable wheel, wherein the hydraulic steering system comprises: a steering cylinder having two chambers and a hydraulic connection each of the two chambers for activating a steering movement of the at least one steerable wheel; at least one hydraulic pump; at least one hydraulic tank for receiving hydraulic oil; a steering block which comprises: two first hydraulic connections for connecting to the two hydraulic connections of the steering cylinder; at least two second hydraulic connections for supplying hydraulic oil from the hydraulic pump to the steering block and feeding the hydraulic oil back into the hydraulic tank; and a controllable valve assembly which receives control signals from a steering angle detection device, wherein the controllable valve assembly is designed to convey hydraulic oil to the steering cylinder on the basis of said control signals and to be shiftable into at least one neutral position in which it allows a flow of hydraulic oil between the two chambers of the steering cylinder; and a pump device which is designed to stimulate the flow of hydraulic oil between the two chambers of the steering cylinder when the valve assembly is in the neutral position, and wherein the pump device is integral with the steering block. ### Claim 10 (depends on 9) Vehicle according to claim 9, wherein the valve assembly is arranged in a counterweight, driver overhead guard, frame or engine compartment of the vehicle.