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Hydro-mechanical and Hydro-electrical Steering Control Circuit

IP.com Disclosure Number: IPCOM000169982D
Publication Date: 2008-May-05
Document File: 4 page(s) / 104K

Publishing Venue

The IP.com Prior Art Database

Related People

Troy E. Schick: AUTHOR [+2]

Abstract

Variable ratio steering is a desired feature for agricultural tractors. A low ratio is useful for quick response in field applications, but a high ratio is desired for slower response when transporting on road. A control system is needed that allows for the combination of electro-hydraulic and hydro-mechanical steering to vary steering ratio.

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Hydro-mechanical and Hydro-electrical Steering Control Circuit

Abstract

    
Variable ratio steering is a desired feature for agricultural tractors. A low ratio is useful for quick response in field applications, but a high ratio is desired for slower response when transporting on road. A control system is needed that allows for the combination of electro-hydraulic and hydro-mechanical steering to vary steering ratio.

Detailed Description


As shown in Fig. 1, steering cylinders 10 and 12 are connected to hydraulic circuit
14. Circuit 14 includes a hydro-mechanical circuit 16 and an electro-hydraulic circuit 18. Circuit 16 includes a conventional orbital steering unit 20 connected to a conventional steering wheel 22. Orbital steering unit 20 controls the flow of hydraulic fluid in line 24 which is connected to the rod chamber of cylinder 10 and to the piston chamber of cylinder 12. Orbital steering unit 20 also controls the flow of hydraulic fluid in line 26 which is connected to the piston chamber of cylinder 10 and to the rod chamber of cylinder 12. Circuit 16 is connected to a variable displacement pump 28 and a reservoir
30.

    Electro-hydraulic circuit 18 includes a solenoid and pilot operated on-off valve 32 which controls communication between pump 28 and reservoir 30 and a solenoid operated left steering valve 34 and a solenoid operated right steering valve 36. Valves 34 and 36 control the flow of hydraulic fluid in line 38 which is connected to the rod chamber of cylinder 10 and to the piston chamber of cylinder 12. Valves 34 and 36 also control the flow of hydraulic fluid in line 40 which is connected to the piston chamber of cylinder 10 and to the rod chamber of cylinder 1...