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WO1993004905A1 - Agencement de commande de direction - Google Patents

Agencement de commande de direction Download PDF

Info

Publication number
WO1993004905A1
WO1993004905A1 PCT/US1991/006233 US9106233W WO9304905A1 WO 1993004905 A1 WO1993004905 A1 WO 1993004905A1 US 9106233 W US9106233 W US 9106233W WO 9304905 A1 WO9304905 A1 WO 9304905A1
Authority
WO
WIPO (PCT)
Prior art keywords
steering control
valve
control means
steering
pilot
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1991/006233
Other languages
English (en)
Inventor
Jerry Dwight Marr
Howard Arthur Marsden
Noel Joy Rytter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Caterpillar Inc
Original Assignee
Caterpillar Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Caterpillar Inc filed Critical Caterpillar Inc
Priority to PCT/US1991/006233 priority Critical patent/WO1993004905A1/fr
Publication of WO1993004905A1 publication Critical patent/WO1993004905A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
    • B62D5/30—Safety devices, e.g. alternate emergency power supply or transmission means to ensure steering upon failure of the primary steering means
    • B62D5/32—Safety devices, e.g. alternate emergency power supply or transmission means to ensure steering upon failure of the primary steering means for telemotor systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D7/00—Steering linkage; Stub axles or their mountings
    • B62D7/06—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins
    • B62D7/14—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering
    • B62D7/148—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering provided with safety devices

Definitions

  • This invention relates to a steering system for a vehicle having both front and rear wheel steering and more particularly to a back-up steering control system.
  • the position and/or rate of movement of many of the components of the steering control arrangement are sensed electronically and electrical input signals directed to the microprocessor for controlling the position of both the front and rear wheels responsive to programmed conditions when requested by the vehicle operator.
  • the present invention is directed to overcoming one or more of the problems as set forth above.
  • a steering control system for a vehicle having first and second pairs of steerable wheels and first and second hydraulic actuators individually operatively connected to the first and second pairs of steerable wheels.
  • the system comprises a hydraulic pump, first and second steering control valves connected to the hydraulic pump and individually connected to the first and second hydraulic actuators respectively, and primary steering control means for controlling the position of the first and second steering control valves to effect steering movement of the first and second pair of steerable wheels.
  • Back-up steering control means are provided for automatically hydraulically powering the first pair of steerable wheels to a straight-ahead condition and for controlling the position of the second steering control valve upon a failure of the primary steering control means.
  • the steering control arrangement includes a back-up steering control means which utilizes hydraulic power for automatically centering the first pair of steerable wheels to a straight-ahead condition upon a failure of the primary steering control means.
  • the back-up steering control means also provides for controlling the position of a steering control valve associated with the second pair of steerable wheels to provide for steering the vehicle when the primary steering control means has failed.
  • the sole figure is a schematic illustration of the steering control arrangement of an embodiment of the present invention.
  • a steering control arrangement 10 for a vehicle has a first pair of steerable wheels 11, a second pair of steerable wheels 12, a first hydraulic actuator 13 operatively connected to the first pair of wheels 11 through a steering linkage 14, a second hydraulic actuator 16 operatively connected to the second pair of wheels through a steering linkage 17, a primary steering control system 18, and a back-up steering control system 19.
  • the primary steering control system 18 includes first and second pilot operated steering control valves 21,22 in fluid communication with the first and second hydraulic actuators 13,16, respectively. Both of the steering control valves are connected to a load sensing variable displacement pump 23 through a supply conduit 24 and to a tank 26 through an exhaust conduit 27.
  • the pump 23 has a displacement controller 28 connected to a load sensing network 29 which is connected to both of the steering control valves 21,22 for directing the highest load pressure in the actuators 13,16 to the displacement controller in the usual manner.
  • the first steering control valve 21 has a first pair of actuating chambers 31,32 at one end thereof and a second pair of actuating chambers 33,34 at the other end thereof.
  • the second steering control valve 22 has a first pair of actuating chambers 36,37 at one end thereof, and a second pair of actuating chambers 38,39 at the other end thereof.
  • the primary steering control system 18 also includes a pilot pump 41 connected to a pilot supply line 42, a plurality of electrohydraulic proportional valves 43,44,46,47 connected to the pilot supply line 42, and a microprocessor 48 connected to the proportional valves 43,44,46,47 through a plurality of electrical leads 49,50,51,52.
  • the proportional valves 43,44 are hydraulically connected to the actuating chambers 31,33, respectively, of the first steering control valve 21.
  • the proportional valves 46,47 are hydraulically connected to the actuating chambers 36,38, respectively of the second steering control valve 22.
  • a manual steering input device 53 includes a position sensor 55 operatively associated with a control handle 56 and is connected to the microprocessor 48 through an electrical lead 57.
  • the microprocessor has a mode selector knob 58 thereon. Further numerous pressure and position sensors, not shown, are operatively associated with various components of the control system 18 and connected to the microprocessor to transmit electrical signals thereto.
  • the back-up steering control system 19 includes a back-up steering control means 59 for automatically hydraulically powering the first pair of steerable wheels 11 to a straight-ahead condition and for controlling the position of the second steering control valve 22 upon a failure of the primary steering control system 18.
  • the back-up steering control means 59 includes a ground driven pump 60 connected to the supply conduit 24 through an auxiliary supply conduit 61.
  • a pilot operated diverter valve 62 is disposed in the auxiliary supply conduit 61 and has opposite ends 63,64.
  • a pilot line 66 connects the pilot supply line 42 to the end 63 of the diverter valve.
  • a spring 67 is connected to the end 64 of the diverter valve.
  • a pilot control valve 68 is connected to the auxiliary supply conduit 61 through a branch conduit 69 having a pressure reducing valve 71 disposed therein.
  • the pilot control valve 68 is connected to the actuating chambers 37,39 of the second steering control valve 22 through a pair of pilot lines 72,73 respectively.
  • the control handle 56 is operatively connected to the pilot control valve 68 for manual actuation thereof.
  • a servo valve 76 is operatively connected to the first actuator 13 through a linkage 77.
  • the servo valve 76 is hydraulically connected to the branch conduit 69 and to the actuating chambers 32,34 of the first control valve 21 through a pair of pilot lines 78,79.
  • a plurality of bleed orifices 81,82,83,84 are individually disposed between the pilot lines 72,73,78,79 and the tank 26.
  • a solenoid actuated selector valve 86 is disposed in the pilot supply line 42 and is connected to the exhaust conduit 27.
  • the selector valve 86 is connected to the microprocessor 48 through an electrical lead 87 and is resiliently biased to a position at which the pilot supply line 42 is vented to the exhaust conduit 27.
  • the selector valve 86 constitutes a means 88 for rendering the back-up steering control means 59 inoperative when the primary steering control system 18 is operative.
  • a pair of check valves 89,90 are suitably disposed in the supply conduit 24 and the auxiliary supply conduit 61, respectively.
  • the microprocessor 48 continuously checks the signals from the sensors to determine if the signals meet programmed parameters. If all signals are within the parameters indicating that the primary steering control system 18 is operational, the microprocessor 48 directs an electrical command signal through the lead 87 to urge the solenoid actuated valve 86 to a position at which fluid from the pilot pump 41 is directed through the pilot supply line 42. The pressurized fluid in the pilot supply line 42 is also communicated through the pilot line 66 to move the diverter valve 62 to a position at which the fluid from the ground driven pump 60 is blocked from the steering control valves 21,22 and is communicated to the exhaust conduit 27. This renders the back-up steering control system 19 inoperative when the primary steering control system 18 is operative.
  • Steering with the primary steering control system is initiated by moving the control handle 56 in the desired direction.
  • an electrical signal commensurate with the direction and degree of movement of the control handle 56 is directed from the sensor 55 through the lead 57 to the microprocessor 48.
  • the microprocessor 48 processes the signal and dependent upon the steering mode selected, directs an appropriate signal through one or more of the electrical leads 49,50,51, or 52.
  • an electrical signal transmitted through the lead 49 actuates the proportional valve 43 to controllably direct pressurized pilot fluid to the actuating chamber 33 to move the steering control valve 21 leftwardly to an operative position.
  • the valve 21 directs fluid from the supply conduit 24 to the hydraulic actuator 13 causing it to move to the right thereby pivoting the wheels 11 simultaneously in a first steering direction.
  • directing an electrical signal through the lead 50 causes the hydraulic actuator 13 to move leftwardly to pivot the wheels 11 in a second steering direction.
  • the wheels 12 are also similarly pivoted in a first or second direction in response to electrical signals transmitted through the leads 51 or 52.
  • the selector knob 58 is operable to select one of four different modes of steering. In one mode, only the wheels 11 are used for steering. In another mode, only the wheels 12 are used for steering. In still another mode, both sets of wheels 11,12 are used for steering in a circle while the final mode is when both sets of wheels 11,12 are used for crab steering.
  • the servo valve 76 is moved from the neutral position shown in response to movement of the hydraulic actuator 13 in either direction. However, since the fluid from the ground driven pump 60 is diverted to the exhaust conduit 27 when the primary steering control system 18 is operating normally, movement of the servo valve 76 has no effect on the positioning of the steering control valve 21. However, should the microprocessor detect that one or more of the signals received thereby do not meet the parameters indicating that a failure has occurred in the primary steering control system 18 or if the microprocessor itself fails, the command signal to the solenoid valve 86 is interrupted and the solenoid valve is biased to the position shown to vent the pilot supply line 42 to the tank.
  • the diverter valve 62 is be spring biased to the operational position for communicating fluid from the ground driven pump 60 to the auxiliary supply conduit line 61.
  • the pressurized fluid passing from the conduit 61 through the pressure reducing valve 71 and the branch conduit 69 is directed by the servo valve 76 to the appropriate one of the actuating chambers 32 or 34 to move the steering control valve 21 to an operating position for directing fluid from the conduit 61 to the actuator 13.
  • Such pressurized fluid moves the actuator 13 back to the position shown thereby centering the wheels 11 in the straight-ahead condition.
  • the servo valve 76 is moved to the neutral position shown subsequently blocking the flow of pilot fluid to the actuating chamber 32 or 34 such that when the wheels 11 reach the centered or straight-ahead position, the steering control valve 21 hydraulically locks the actuator 13 and thus the wheels 11 in the straight-ahead position.
  • the back-up steering control system 19 is now operative to hydraulically control the position of the steering control valve 22. More specifically, clockwise movement of the control handle 56 causes the pilot control valve 68 to direct pressurized fluid through the pilot line 73 to the actuating chamber 39, thereby moving the steering control valve 22 leftwardly as viewed in the drawing.
  • the structure of the present invention provides an improved steering control arrangement having a back-up steering control system which automatically hydraulically moves a first pair of steerable wheels to a straight-ahead position when a failure occurs in the primary steering control system and the first pair of steerable wheels are in a pivoted steering position.
  • the back-up steering control system Since the back-up steering control system is essentially inoperative when the primary steering control system is operational, no substantial additional expenditure of hydraulic energy is wasted during the normal steering conditions. Moreover, the back-up steering control system provides an additional supply of hydraulic fluid for steering a second pair of steerable wheels for maneuvering the vehicle when a failure occurs in the primary steering control system.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Power Steering Mechanism (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)

Abstract

Des véhicules comprenant des paires de roues avant et arrière orientables sont quelquefois équipés de grands ressorts servant à placer une paire de roues en position d'avance en droite ligne au cours d'une man÷uvre d'urgence. Un apport important en énergie hydraulique est nécessaire uniquement pour comprimer de tels ressorts à chaque fois que la paire de roues est man÷uvrée. Le système de commande de direction de secours (19) du présent agencement de commande de direction (10) comprend une soupape asservie (76) servant à réguler l'écoulement de fluide sous pression à partir d'une pompe de secours (60) vers une soupape de commande de direction (21), qui à son tour commande l'écoulement du fluide sous pression de la pompe de secours vers l'actionneur hydraulique (13) afin d'effectuer le déplacement hydraulique d'une première paire de roues orientables (11) en une position d'avance en droite ligne dans des conditions de man÷uvre d'urgence. Une soupape de commande manuelle (68) fonctionne de façon à réguler l'écoulement du fluide sous pression de la pompe de secours (60) vers une seconde soupape de commande de direction (22) qui régule à son tour l'écoulement du fluide sous pression vers l'actionneur hydraulique (16) afin de diriger une seconde paire de roues orientables (12) dans des conditions de man÷uvre d'urgence.
PCT/US1991/006233 1991-09-03 1991-09-03 Agencement de commande de direction Ceased WO1993004905A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US1991/006233 WO1993004905A1 (fr) 1991-09-03 1991-09-03 Agencement de commande de direction

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1991/006233 WO1993004905A1 (fr) 1991-09-03 1991-09-03 Agencement de commande de direction

Publications (1)

Publication Number Publication Date
WO1993004905A1 true WO1993004905A1 (fr) 1993-03-18

Family

ID=22225780

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1991/006233 Ceased WO1993004905A1 (fr) 1991-09-03 1991-09-03 Agencement de commande de direction

Country Status (1)

Country Link
WO (1) WO1993004905A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104058001A (zh) * 2013-12-13 2014-09-24 湖北三江航天万山特种车辆有限公司 带多模式转向和自动对中功能的双向驾驶车辆液压系统
DE102015006625B4 (de) * 2014-09-18 2021-02-18 Liebherr-Werk Bischofshofen Gmbh Elektrohydraulisches Lenksystem, Verfahren zur Funktionsprüfung eines solchen elektrohydraulischen Lenksystems, Lenksystem und mobile Arbeitsmaschine
US11396323B2 (en) 2017-04-03 2022-07-26 Deere & Company Electro-hydraulic steering control system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4131177A (en) * 1976-11-23 1978-12-26 Goodbary Engineering Company Dual steering system for vehicles
US4736811A (en) * 1987-05-22 1988-04-12 Caterpillar Inc. Steering control system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4131177A (en) * 1976-11-23 1978-12-26 Goodbary Engineering Company Dual steering system for vehicles
US4736811A (en) * 1987-05-22 1988-04-12 Caterpillar Inc. Steering control system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104058001A (zh) * 2013-12-13 2014-09-24 湖北三江航天万山特种车辆有限公司 带多模式转向和自动对中功能的双向驾驶车辆液压系统
CN104058001B (zh) * 2013-12-13 2016-08-31 湖北三江航天万山特种车辆有限公司 带多模式转向和自动对中功能的双向驾驶车辆液压系统
DE102015006625B4 (de) * 2014-09-18 2021-02-18 Liebherr-Werk Bischofshofen Gmbh Elektrohydraulisches Lenksystem, Verfahren zur Funktionsprüfung eines solchen elektrohydraulischen Lenksystems, Lenksystem und mobile Arbeitsmaschine
US11396323B2 (en) 2017-04-03 2022-07-26 Deere & Company Electro-hydraulic steering control system
DE102018204834B4 (de) * 2017-04-03 2025-06-26 Deere & Company Elektrohydraulisches lenksteuersystem

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