WO1994006668A1 - Direction assistee a cremaillere, notamment pour automobiles - Google Patents

Direction assistee a cremaillere, notamment pour automobiles Download PDF

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Publication number
WO1994006668A1
WO1994006668A1 PCT/EP1993/002464 EP9302464W WO9406668A1 WO 1994006668 A1 WO1994006668 A1 WO 1994006668A1 EP 9302464 W EP9302464 W EP 9302464W WO 9406668 A1 WO9406668 A1 WO 9406668A1
Authority
WO
WIPO (PCT)
Prior art keywords
pinion
rack
piston
power assisted
steering
Prior art date
Application number
PCT/EP1993/002464
Other languages
German (de)
English (en)
Inventor
Wilfried Leutner
Helmut KNÖDLER
Original Assignee
Zf Friedrichshafen Aktiengesellschaft
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 Zf Friedrichshafen Aktiengesellschaft filed Critical Zf Friedrichshafen Aktiengesellschaft
Priority to EP93920704A priority Critical patent/EP0659135A1/fr
Publication of WO1994006668A1 publication Critical patent/WO1994006668A1/fr

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
    • B62D5/08—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by type of steering valve used
    • B62D5/087—Sliding spool valves
    • 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
    • B62D5/20—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle specially adapted for particular type of steering gear or particular application
    • B62D5/22—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle specially adapted for particular type of steering gear or particular application for rack-and-pinion type

Definitions

  • the invention relates to a power steering rack, in particular for motor vehicles, according to the preamble of claim 1.
  • a pinion is rotatably mounted in a steering housing.
  • a rack is axial in the steering housing
  • a servo motor which is connected to the rack and pinion, is used for auxiliary power support.
  • a control device for controlling a pressure medium to and from the servo motor ⁇ _5 is adjustable as a function of a movement of the pinion.
  • Such a power assisted rack and pinion steering is known from EP-Bl-01 92 641.
  • the helical toothing of the pinion creates a force component on the pinion in the axial direction, so that the pinion is adjustable in the axial direction.
  • the control valves can be adjusted by this axial displacement of the pinion.
  • the helix angle of the pinion should be above 35 degrees if possible. This severely limits the choice of pinion teeth.
  • the actuation of the control valves can be affected by the fact that the transverse forces on the
  • the invention has for its object to avoid the shortcomings described without additional design effort.
  • the use of pinions with different helix angles should be possible, even with helix angles that are less than 35 degrees.
  • the solution is achieved in particular in that the pinion is pivotally mounted in a fixed bearing and in a floating bearing.
  • the control device is designed in the form of a piston valve which is arranged in the region of the floating bearing and whose axis is essentially perpendicular to the axis of the pinion. This means that it is not the axial forces acting on the pinion that are used to actuate the control valve, but rather the transverse forces. If the steering spindle is turned, the toothing of the pinion initially rolls in the toothing of the still fixed rack and thus moves the pin of the pinion guided in the floating bearing, so that the
  • Piston valve is adjusted. Small movements of the pinion are sufficient to actuate and control the piston valve. These minimal control paths and the associated small movements of the pinion in its floating bearing make it possible to mount the pinion on one side, for example on the steering spindle side, with a fixed bearing. The pivot angle of the pinion is then so small that the set within the toothing remains within the permissible range.
  • Expedient and advantageous embodiments of the invention are specified in the subclaims. However, the invention is not limited to the combinations of features of the claims. For the specialist, there are further useful combinations of claims and individual claim characteristics from the task.
  • FIG. 1 shows a longitudinal section through the power assisted steering system according to the invention
  • FIG. 2 shows a partial cross section through the power assisted-rack steering system of FIG. 1 in the region of the pinion;
  • Fig. 3 shows a longitudinal section through a power steering system according to the invention with speed-dependent reaction force.
  • a pinion 2 is rotatably mounted in two bearings 3 and 4.
  • the pinion 2 carries at one end a steering shaft connection 5 for connection to
  • Steering element for example a steering spindle, not shown, with a steering handwheel.
  • One of the bearings preferably the bearing 3, which is located in the vicinity of the steering spindle connection 5, is designed as a fixed bearing.
  • the other bearing preferably the bearing 4, which faces away from the steering spindle connection 5, is designed as a floating bearing.
  • the pinion 2 is in engagement with a toothed rack 6, which is guided axially displaceably in the steering housing 1.
  • the rack 6 is countered with the aid of a spring-loaded pressure piece 7 in a known manner pressed the teeth of the pinion 2.
  • the pinion 2 is supported on one side in the fixed bearing 3 and on the other side via the floating bearing 4 in the steering housing 1.
  • the pressure plate 10 serves to enable a low-friction and low-wear movement of the floating bearing 4.
  • the outer ring 8 of the floating bearing 4 can roll on the pressure plate 10.
  • the pressure plate 10 can optionally be dispensed with.
  • a servo motor 11 is used for auxiliary power support, the piston rod 12 of which is firmly connected to the rack 6.
  • the servo motor 11 contains two cylinder spaces 13 and 14, which are connected via working lines 15 and 16 to two cylinder connections 17 and 18 of a control device 20.
  • the control device 20 also has an inlet connection 21 to which a servo pump 22 is connected.
  • a container 25 is connected to two return connections 23 and 24.
  • the control device 20 contains a piston valve 26, the axis of which is substantially perpendicular to the axis of the pinion 2.
  • the piston valve 26 is arranged in the area of the floating bearing 4.
  • the piston valve 26 contains a piston 27 which is arranged displaceably in a bore 28 of the steering housing 1 and is centered in its central position by two springs 30 and 31.
  • the piston 27 is carried along via a pin-like extension 32 of the pinion 2, which has a spherical or spherical end and engages in a recess 33 of the piston 27.
  • the recess 33 is designed as a bore in the piston 27.
  • the piston valve 26 has on its piston 27 control grooves 34 with control edges, which cooperate in a known manner with control grooves 35 of the bore 28 and are connected in a known manner to the cylinder connections 17 and 18, the inlet connection 21 and the return connections 23 and 24.
  • the control grooves 34 and 35 are all on one side of the recess 33.
  • the piston 27 is sealed in the bore 28 by two seals 36 and 37 in such a way that the pressure medium controlled via the piston valve 26 to and from the servo motor 11 remains restricted to the area of the control grooves 34 and 35.
  • Light alloy casting of the steering must be pressure-tight only in the area of the piston 27 and the servo motor 11.
  • the reaction force can be varied as a function of the driving speed.
  • the cylinder pressure can act on two piston chambers 41, 42 of the piston valve 26.
  • the pressure oil can reach the tank via an orifice 43, 44, a cut-off valve 45 and an orifice 46 which is electrically adjustable depending on the driving speed.
  • a spring-loaded piston is displaceably arranged in the cut-off valve 45, on which the pump pressure acts on one side and the reduced cylinder pressure acts on the other side.
  • the pinion 2 is pivoted about the fixed bearing 3 by a small angle.
  • the floating bearing 4 is shifted to the left.
  • This movement is transmitted to the piston 27 via the extension 32 of the pinion 2 and the recess 33.
  • the piston 27 moves to the left against the force of the spring 30.
  • a pressure is thus regulated at the control grooves 34 and 35, which propagates in the cylinder space 13 and shifts the rack 6 to the right in accordance with the movement on the steering handwheel.
  • the cylinder pressure of the left cylinder chamber 13 is also present in the piston chamber 41.
  • the pressure to the tank is reduced via the orifices 43 and 46, so that, depending on the opening of the orifice 46, part of the cylinder pressure is present in the piston chamber 42.
  • control grooves 34 and 35 are constructed symmetrically to one another, a corresponding functional sequence results when the steering handwheel is in the opposite direction of rotation.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Power Steering Mechanism (AREA)
  • Transmission Devices (AREA)

Abstract

Dans une direction assistée à crémaillère, prévue notamment pour des automobiles, un pignon (2) logé dans un carter de direction (1) est en prise avec une crémaillère (6). Afin de permettre la servo-assistance, un servomoteur (11) est relié cinétiquement à la crémaillère (6). Le pignon (2) est logé pivotant dans un palier fixe (3) et dans un palier libre (4). Une soupape à piston (26) montée dans la zone du palier libre (4) a un axe sensiblement perpendiculaire à l'axe du pignon (2). Le palier libre (4) est guidé coulissant perpendiculairement à son axe, uniquement en direction de l'axe de la soupape à piston (26) dans le carter de direction (1). Dans cette direction assistée à crémaillère, pour actionner les soupapes de commande, on n'utilise pas les forces axiales qui agissent sur le pignon (2), mais les forces transversales. L'actionnement des soupapes de commande ne dépend donc pas de l'angle d'hélice des dents du pignon.
PCT/EP1993/002464 1992-09-16 1993-09-13 Direction assistee a cremaillere, notamment pour automobiles WO1994006668A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP93920704A EP0659135A1 (fr) 1992-09-16 1993-09-13 Direction assistee a cremaillere, notamment pour automobiles

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP4230960.3 1992-09-16
DE19924230960 DE4230960A1 (de) 1992-09-16 1992-09-16 Zahnstangen-Hilfskraftlenkung, insbesondere für Kraftfahrzeuge

Publications (1)

Publication Number Publication Date
WO1994006668A1 true WO1994006668A1 (fr) 1994-03-31

Family

ID=6468082

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1993/002464 WO1994006668A1 (fr) 1992-09-16 1993-09-13 Direction assistee a cremaillere, notamment pour automobiles

Country Status (3)

Country Link
EP (1) EP0659135A1 (fr)
DE (1) DE4230960A1 (fr)
WO (1) WO1994006668A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995030568A1 (fr) * 1994-05-05 1995-11-16 Zf Friedrichshafen Ag Direction assistee a cremaillere, notamment pour vehicules automobiles

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19612872A1 (de) * 1996-03-30 1997-10-02 Zahnradfabrik Friedrichshafen Hilfskraftlenkung, insbesondere für Kraftfahrzeuge
DE19956858A1 (de) 1999-11-25 2001-06-07 Zf Lenksysteme Gmbh Abschneidventil für Hilfskraftlenkungen, insbesondere für Kraftfahrzeuge
DE102006050507A1 (de) * 2006-10-26 2008-04-30 Zf Lenksysteme Gmbh Abschneidventil

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2747484A1 (de) * 1977-10-22 1979-04-26 Bosch Gmbh Robert Hydraulischer lenkverstaerker fuer speicher- und durchflusslenkung
DE3024025A1 (de) * 1979-06-27 1981-01-22 Honda Motor Co Ltd Servo-lenkvorrichtung
US4299302A (en) * 1978-11-14 1981-11-10 Honda Giken Kogyo Kabushiki Kaisha Power steering device for vehicles
DE3502537A1 (de) * 1984-01-27 1985-09-05 Nissan Motor Co., Ltd., Yokohama, Kanagawa Fahrzeuglenkung
EP0192641B1 (fr) * 1983-11-05 1988-01-07 ZF FRIEDRICHSHAFEN Aktiengesellschaft Direction assistee a cremaillere, en particulier pour vehicules a moteur

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2747484A1 (de) * 1977-10-22 1979-04-26 Bosch Gmbh Robert Hydraulischer lenkverstaerker fuer speicher- und durchflusslenkung
US4299302A (en) * 1978-11-14 1981-11-10 Honda Giken Kogyo Kabushiki Kaisha Power steering device for vehicles
DE3024025A1 (de) * 1979-06-27 1981-01-22 Honda Motor Co Ltd Servo-lenkvorrichtung
EP0192641B1 (fr) * 1983-11-05 1988-01-07 ZF FRIEDRICHSHAFEN Aktiengesellschaft Direction assistee a cremaillere, en particulier pour vehicules a moteur
DE3502537A1 (de) * 1984-01-27 1985-09-05 Nissan Motor Co., Ltd., Yokohama, Kanagawa Fahrzeuglenkung

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995030568A1 (fr) * 1994-05-05 1995-11-16 Zf Friedrichshafen Ag Direction assistee a cremaillere, notamment pour vehicules automobiles
US5904221A (en) * 1994-05-05 1999-05-18 Zf Friedrichshafen Ag Toothed-rack power-assisted steering in particular for motor vehicles

Also Published As

Publication number Publication date
DE4230960A1 (de) 1994-03-17
EP0659135A1 (fr) 1995-06-28

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