EP1044128A1 - Ensemble soupape pour direction assistee - Google Patents

Ensemble soupape pour direction assistee

Info

Publication number
EP1044128A1
EP1044128A1 EP99958008A EP99958008A EP1044128A1 EP 1044128 A1 EP1044128 A1 EP 1044128A1 EP 99958008 A EP99958008 A EP 99958008A EP 99958008 A EP99958008 A EP 99958008A EP 1044128 A1 EP1044128 A1 EP 1044128A1
Authority
EP
European Patent Office
Prior art keywords
steering
valve
hydraulic system
steering according
hydraulically
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.)
Withdrawn
Application number
EP99958008A
Other languages
German (de)
English (en)
Inventor
Alfred SCHÖFFLER
Martin Rothmund
Wolfram Thomas
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.)
ThyssenKrupp Presta Muelheim GmbH
Original Assignee
Mercedes Benz Lenkungen GmbH
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 Mercedes Benz Lenkungen GmbH filed Critical Mercedes Benz Lenkungen GmbH
Publication of EP1044128A1 publication Critical patent/EP1044128A1/fr
Withdrawn legal-status Critical Current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
    • B62D5/061—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle provided with effort, steering lock, or end-of-stroke limiters

Definitions

  • the present invention relates to a hydraulically assisted steering system for a motor vehicle with the features of the preambles of claims 1 or 2.
  • a conventional power steering system of this type has, in addition to the rotary slide valve or rotary piston valve, one or two valves for limiting the deflection of the steering shaft as well as a pressure limiting valve and a suction valve, the pressure limiting valve limiting the pressure upstream of the power steering and that
  • Limit valves establish a hydraulic connection between the two working spaces of the working piston. The power assistance is reduced and the steering angle is effectively limited in this way.
  • This object is in a recirculating ball steering from a steering system with the features of claim 1 and at a Rack and pinion steering solved by a steering system with the features of claim 2.
  • the operation of the power steering can be influenced depending on the measurement results of electrical sensors or other control commands.
  • At least one sensor is provided for the position of the steering, the circuit being set up to control the valve as a function of the sensor.
  • the above-mentioned steering stop can be simulated by reducing the power assistance.
  • a specific characteristic of the servo support can also be achieved by specifically influencing the servo support as a function of the steering angle.
  • the circuit is assigned a sensor for the speed of the motor vehicle and the maximum desired wheel angle is variable as a function of the speed, a steering stop can be prevented at higher speeds, which would lead to unsafe driving conditions. At low
  • valve is arranged inside the steering housing.
  • the valve can be mounted in a particularly accessible location without changes to existing steering housings if it is arranged outside the housing, in particular in the area of a hydraulic line.
  • z. B. be provided that the flow of the hydraulic pump and the reservoir are connected to each other, whereby the two working spaces of the power steering are indirectly hydraulically coupled. The effect is essentially the same.
  • a pressure sensor is assigned to the circuit and the valve is opened when a certain pressure or a certain pressure difference is reached.
  • the valve can also provide an autonomous mechanical pressure limitation by operating at a certain point without triggering the circuit Pressurization opens. This can prevent overpressure in the hydraulic system, particularly in the case of cold hydraulic fluid, without the electronic circuit having to respond. If the valve is opened in the event of a drop in pressure in the hydraulic system, the purely mechanical actuation of the power steering by manual force is not impaired in any case because the servo support has ceased to exist anyway, because a bypass is created from one work area to the other work area. The same applies in the event that the valve is open when de-energized. In this embodiment, the suction valve, which is otherwise provided for this case, can be omitted.
  • valve in the open state represents a throttle cross section, which ensures a minimum pressure difference between the working spaces when the hydraulic system is pressurized. This has the effect that if the pressure relief valve fails, for example due to a broken cable while driving, the steerability of the vehicle is ensured with a minimum of servo assistance.
  • FIG. 1 A basic circuit diagram of a hydraulic power steering system as a recirculating ball steering system with the new valve arrangement for connecting the working spaces; such as
  • FIG. 1 shows a hydraulic steering system according to the invention as a recirculating ball steering system with a steering housing 1, in which a working piston 2 with two working spaces 3 and 4 and a steering shaft 5 are arranged.
  • Working spaces 3 and 4 are connected via hydraulic lines 6 and 7 mt to a servo valve 8 m.
  • the servo valve 8 is in turn connected via a hydraulic line 9 to the one in the flow of a hydraulic pump 10 and via a hydraulic line 11 to a reservoir or oil container 18.
  • the working spaces 3 and 4 are connected to one another via a two-way solenoid valve 12, which is open in the idle state.
  • the two-way solenoid valve is controlled electrically via a control device 13.
  • the control device 13 receives electrical measured values of a speed sensor 14 for the vehicle speed, one
  • FIG. 2 shows a block diagram corresponding to FIG. 1 with a connection of the pump flow and the storage container.
  • the same components are provided with the same reference numbers.
  • the steering system described so far works as follows: With the hydraulic pump 10 running, an Olstro is first built up in the steering circuit. The resulting pressure is measured via the pressure sensor 16 and transmitted to the control device 13. In operation, the control device 13 outputs a control line
  • the control device 13 influences the function of the steering m as a function of the signals from the sensors 14, 15 and 16. If the maximum permissible steering lock is determined via the angle of rotation sensor 15 of the steering shaft 5, the control device 13 opens the two-way solenoid valve 12, so that an immediate hydraulic connection between the lines 6 and 7 and thus a pressure equalization in the working spaces 3 and 4. This reduces the power assistance to the steering and the increasing effort that can be felt on the steering wheel of the motor vehicle simulates a mechanical stop on the steering. A further steering lock in the chosen direction is therefore generally avoided. Damage to the motor vehicle or other undesirable consequences of a wheel angle that is too large are reliably avoided in this way.
  • the point at which the solenoid valve 12 opens when certain wheel lock angles are reached can be changed as a function of the speed sensor 14. So z. B. limits the maximum steering angle at a certain driving speed be by the solenoid valve 12 opens at a smaller wheel angle than at a standstill. In this way, the steering locks during driving can be limited to an area that ensures safe driving conditions
  • control device 13 determines the pressure in the supply line 9 via the sensor 16 and can open the solenoid valve 12 in the event of a complete pressure drop.
  • the effect of this switching possibility is that manual servicing of the steering is not additionally hampered by a large flow resistance of the hydraulic fluid from one working space 3, 4 into the other working space 4, 3 in any case if there is no servo assistance.
  • the controller 13 can also open the solenoid valve 12 in order to allow a pressure reduction and thus to avoid damage to the pump or the hydraulic system.
  • the control device 13 can also control the two-way solenoid valve in a pulsed or clocked manner, so that a pressure limitation or pressure reduction can be implemented in the flow of the power steering.
  • the embodiment according to FIG. 1 has the advantage that when the overpressure limitation responds, the hydraulic fluid is pumped through a relatively long circuit and thus a relatively large amount is circulated. This prevents overheating and damage to the fluid. A (faulty) completely closed servo valve, however, leads to an increase in pressure in the pump flow 9, which cannot be prevented by opening the valve 8.
  • the two-way solenoid valve 12 in connection with the control device 13 thus enables the functions of conventional limit valves for the maximum steering lock, of pressure limit valves and of suction valves.
  • the arrangement described so far can be kept cheaper in terms of material and assembly costs than conventional steering systems, in which a total of up to four purely mechanical valves are used, which correspond to up to three different types.
  • sensors 14 and 15 as well as control unit 13 and possibly sensor 16 are also available anyway, so that the corresponding functions only have to be implemented.
  • the power steering can be controlled via the two-way solenoid valve 12, which takes into account the driving states determined in each case.

Landscapes

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

Abstract

L'invention concerne une direction assistée hydraulique pour un véhicule automobile. Selon l'invention, il n'est plus nécessaire d'avoir recours à des soupapes mécaniques classiques de limitation de pression, de réaspiration et de butée de fin de course car une soupape électromécanique (12) est affectée au système hydraulique et assure, à l'état ouvert, une liaison hydraulique directe ou non entre les chambres de travail (3, 4).
EP99958008A 1998-11-11 1999-11-08 Ensemble soupape pour direction assistee Withdrawn EP1044128A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19852061 1998-11-11
DE19852061A DE19852061A1 (de) 1998-11-11 1998-11-11 Ventilanordnung für Servolenkungen
PCT/EP1999/008543 WO2000027686A1 (fr) 1998-11-11 1999-11-08 Ensemble soupape pour direction assistee

Publications (1)

Publication Number Publication Date
EP1044128A1 true EP1044128A1 (fr) 2000-10-18

Family

ID=7887463

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99958008A Withdrawn EP1044128A1 (fr) 1998-11-11 1999-11-08 Ensemble soupape pour direction assistee

Country Status (5)

Country Link
US (1) US6345682B1 (fr)
EP (1) EP1044128A1 (fr)
BR (1) BR9907235A (fr)
DE (1) DE19852061A1 (fr)
WO (1) WO2000027686A1 (fr)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10118739A1 (de) 2001-04-17 2002-11-14 Trw Fahrwerksyst Gmbh & Co Verfahren zum Steuern eines Servolenksystems
US20080257633A1 (en) * 2004-08-16 2008-10-23 Arvinmeritor Technology, Llc. Hydro-Mechanically Coupled Electric Power Steering System
US7530422B2 (en) * 2004-09-17 2009-05-12 Delphi Technologies, Inc. Force and position control for active front steering
US20080296084A1 (en) * 2004-11-11 2008-12-04 Continental Teves Ag & Co. Ohg Vehicle Steering System and Method For Controlling a Vehicle Steering System
US7225894B2 (en) * 2005-01-27 2007-06-05 Trw Automotive U.S. Llc Power steering apparatus
US7793752B2 (en) * 2005-05-05 2010-09-14 Gm Global Technology Operations, Inc. Method of determining boost direction in a power steering system
US9321479B2 (en) * 2007-11-28 2016-04-26 GM Global Technology Operations LLC Vehicle power steering waste heat recovery
DE102010043679B4 (de) * 2010-11-10 2024-02-01 Knorr-Bremse Systeme für Nutzfahrzeuge GmbH Betriebsverfahren für ein hydraulisches Servo-Lenksystem und hydraulisches Servo-Lenksystem
US20120222911A1 (en) * 2011-03-03 2012-09-06 Trw Automotive U.S. Llc Method and apparatus for use in turning steerable vehicle wheels
KR101734688B1 (ko) * 2015-10-15 2017-05-11 현대자동차주식회사 Ehps 시스템을 이용한 유압식 isg 시스템의 작동제어방법 및 장치

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4457390A (en) * 1982-06-16 1984-07-03 Tokai Trw & Co. Ltd. Power steering device
JPS6127770A (ja) * 1984-07-17 1986-02-07 Nissan Motor Co Ltd 後輪操舵装置
JPS63232074A (ja) * 1987-03-20 1988-09-28 Toyota Central Res & Dev Lab Inc 車両用操舵装置
ES2051600T3 (es) * 1990-08-24 1994-06-16 Zahnradfabrik Friedrichshafen Direccion hidraulica asistida.
DE4118947A1 (de) * 1990-08-31 1992-03-12 Bosch Gmbh Robert Servolenkeinrichtung fuer ein fahrzeug
DE4342663A1 (de) * 1993-12-14 1995-06-22 Baerbel Klauke Speicherplatzarme Überwachung von Zahlungsterminen
JPH08142889A (ja) * 1994-11-18 1996-06-04 Unisia Jecs Corp パワーステアリング装置
DE19514244A1 (de) * 1995-04-15 1996-10-17 Trw Fahrwerksyst Gmbh & Co Hydraulische Zahnstangenlenkung
DE19546733C1 (de) * 1995-12-14 1997-03-27 Daimler Benz Ag Hydraulische Servolenkung
DE19626540C1 (de) * 1996-07-02 1997-11-20 Daimler Benz Ag Hydraulische Servolenkung für Kraftfahrzeuge
KR100192381B1 (ko) * 1996-12-05 1999-06-15 정몽규 자동차의 동력조향장치
DE19717796C2 (de) * 1997-04-26 1999-03-04 Zahnradfabrik Friedrichshafen Hilftskraftlenkung mit hydraulischer Hilfskraftunterstützung

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0027686A1 *

Also Published As

Publication number Publication date
US6345682B1 (en) 2002-02-12
DE19852061A1 (de) 2000-05-18
WO2000027686A1 (fr) 2000-05-18
BR9907235A (pt) 2000-10-17

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