WO2005021358A1 - Rotary disk valve comprising control edges and control grooves for use in power-assisted steering systems with variable hydraulic volume flow - Google Patents

Rotary disk valve comprising control edges and control grooves for use in power-assisted steering systems with variable hydraulic volume flow Download PDF

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Publication number
WO2005021358A1
WO2005021358A1 PCT/EP2004/008684 EP2004008684W WO2005021358A1 WO 2005021358 A1 WO2005021358 A1 WO 2005021358A1 EP 2004008684 W EP2004008684 W EP 2004008684W WO 2005021358 A1 WO2005021358 A1 WO 2005021358A1
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WO
WIPO (PCT)
Prior art keywords
control
power steering
volume flow
power
chamfer
Prior art date
Application number
PCT/EP2004/008684
Other languages
German (de)
French (fr)
Inventor
Hartmut Augustin
Edwin Breuning
Rüdiger RACHEL
Original Assignee
Thyssenkrupp Presta Steertec 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 Thyssenkrupp Presta Steertec Gmbh filed Critical Thyssenkrupp Presta Steertec Gmbh
Publication of WO2005021358A1 publication Critical patent/WO2005021358A1/en

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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
    • B62D5/083—Rotary valves
    • B62D5/0837—Rotary valves characterised by the shape of the control edges, e.g. to reduce noise

Definitions

  • the invention relates to a hydraulic power steering system with the features of the preamble of claim 1.
  • the aim of power steering systems with a controllable hydraulic pump has been to keep the influences of the varying hydraulic flow on the power assist as small as possible.
  • the servo support can be varied in a targeted manner by the hydraulic pump delivering a large volume flow at low speeds and thus causing a large servo support, while at high speeds a low volume flow is generated and the servo support is therefore lower.
  • the steering is smooth in the first case, even when parking, while in the second case the steering requires more manual effort and gives a more direct driving experience.
  • this design is not solved satisfactorily. It is therefore an object of the present invention to make the so-called spread of the characteristic curves as large as possible with the different flow rates of the hydraulic pump.
  • control edges each have an inner chamfer and an outer chamfer of different inclinations and are, in particular, convex, the servo support is made available at a low volume angle of the rotary slide valve when the volume flow is high, while a relatively larger angle of rotation is required at a low volume flow is accompanied by a greater hand force on the steering wheel.
  • FIG. 1 shows the geometry of the inner chamfer and outer chamfer in three variants with a control groove of a power steering system according to the invention.
  • the angle of the inner chamfer is constant, while the angle of the outer chamfer assumes three different values.
  • the angle of the inner chamfer can be very steep with respect to the lateral surface and can be up to 90 °, that is to say run almost or completely in the radial direction, while the outer chamfer has an angle of approximately 75 °.
  • the transition between the chamfers can be designed as an edge or rounded.
  • FIG. 2 shows two sets of curves which represent the characteristic curves for a volume flow of 2 liters per minute (denoted by 1) and for 9 1 / min (denoted by 2).
  • the manual torque (x-axis) introduced is plotted on the steering column or on the rotary slide valve against the pressure built up on the associated hydraulic work space of the power steering system on the y-axis.
  • the delivery rate of the servo pump can now be controlled or regulated in a simple manner depending on the driving state parameters (speed, etc.).
  • a particularly large spread can be achieved by the following features:
  • the inner chamfer and the outer chamfer have different angles of inclination, and the transition can be designed as an edge or rounding.
  • the inclination of the inner chamfer with respect to the circumferential direction of the rotary valve can be up to 90 °.
  • the angle difference should be as large as possible so that the inner chamfer closes as quickly as possible, while the outer chamfer closes as slowly as possible.
  • the inner chamfer should determine the characteristic in the range of 20 to 30 bar servo pressure with a large volume flow.
  • the outer chamfer should determine the characteristic in the range of 20 to 30 bar servo pressure with a low volume flow.

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

Abstract

The invention relates to a hydraulic power-assisted steering system for motor vehicles. Said steering system comprises a hydraulic servomotor, a rotary disk valve comprising control grooves and control edges, and a power-steering pump that is adapted to provide at least two different volume flows of a hydraulic fluid during operation. In order to allow for a parameterability of the valve, the inside bevels and outside bevels of the control edges have different inclinations.

Description

DREHSCHIEBERVENTIL MIT STEUERKANTEN UND STEUERNUTEN FÜR SERVOLENKUNGEN MIT VARIABLEM HYDRAULIKVOLUMENSTROMROTARY VALVE WITH CONTROL EDGES AND CONTROL SLOTS FOR POWER STEERING WITH VARIABLE HYDRAULIC VOLUME FLOW
Die Erfindung betrifft ein eine hydraulische Servolenkung mit den Merkmalen des Oberbegriffs des Anspruchs 1.The invention relates to a hydraulic power steering system with the features of the preamble of claim 1.
Bislang ist bei Servolenkungen mit einer regelbaren Hydraulikpumpe angestrebt worden, die Einflüsse des variierenden Hydraulikstroms auf die Servounterstützung möglichst gering zu halten. Andererseits kann die Servounterstützung gezielt variiert werden, indem bei geringen Geschwindigkeiten die Hydraulikpumpe einen großen Volumenstrom abgibt und so eine große Servounterstützung bewirkt, während bei hohen Geschwindigkeiten ein geringer Volumenstrom erzeugt wird und damit die Ser- vounterstützung geringer wird. Die Lenkung ist im ersten Fall leichtgängig, auch beim Einparken, während im zweiten Fall die Lenkung eine höhere Handkraft erfordert und ein direkteres Fahrgefühl vermittelt. Bei den bekannten hydraulischen Servolenkungen ist diese Auslegung nicht zufriedenstellend gelöst. Es ist deshalb Aufgabe der vorliegenden Erfindung, die sogenannte Spreizung der Kennlinien bei den unterschiedlichen Förderströmen der Hydraulikpumpe möglichst groß zu machen.So far, the aim of power steering systems with a controllable hydraulic pump has been to keep the influences of the varying hydraulic flow on the power assist as small as possible. On the other hand, the servo support can be varied in a targeted manner by the hydraulic pump delivering a large volume flow at low speeds and thus causing a large servo support, while at high speeds a low volume flow is generated and the servo support is therefore lower. The steering is smooth in the first case, even when parking, while in the second case the steering requires more manual effort and gives a more direct driving experience. In the known hydraulic power steering systems, this design is not solved satisfactorily. It is therefore an object of the present invention to make the so-called spread of the characteristic curves as large as possible with the different flow rates of the hydraulic pump.
Diese Aufgabe wird von einer Servolenkung mit den Merkmalen des Anspruchs 1 gelöst.This object is achieved by a power steering system with the features of claim 1.
Weil die die Steuerkanten jeweils eine Innenfase und eine Außenfase unterschiedlicher Neigung aufweisen und insbesondere konvex ausgeführt sind, wird bei einem großen Volumenstrom die Servounterstützung bereits bei geringen Drehwinkeln des Dreh- schieberventils zur Verfügung gestellt, während bei geringem Volumenstrom ein relativ größerer Drehwinkel erforderlich ist, der mit einer größeren Handkraft am Lenkrad einher geht.Because the control edges each have an inner chamfer and an outer chamfer of different inclinations and are, in particular, convex, the servo support is made available at a low volume angle of the rotary slide valve when the volume flow is high, while a relatively larger angle of rotation is required at a low volume flow is accompanied by a greater hand force on the steering wheel.
Weitere vorteilhafte Merkmale sind in den abhängigen Ansprüchen angegeben.Further advantageous features are specified in the dependent claims.
Nachfolgend soll ein Ausführungsbeispiel der Erfindung anhand der Zeichnung erläutert werden. Es zeigen:An exemplary embodiment of the invention will be explained below with reference to the drawing. Show it:
Fig. 1: die Geometrie von Innenfase und Außenfase in drei Varianten bei einer Steuernut einer erfindungsgemäßen Servolenkung; sowie1: the geometry of the inner chamfer and outer chamfer in three variants with a control groove of a power steering system according to the invention; such as
Fig. 2: die mit den Varianten gemäß Figur 1 erzielten Kennlinien bei zwei verschiedenen Volumenströmen der Hydraulikpumpe .2: the characteristic curves achieved with the variants according to FIG. 1 with two different volume flows of the hydraulic pump.
In der Figur 1 ist die Geometrie von Innenfase und Außenfase in drei Varianten bei einer Steuernut einer erfindungsgemäßen Servolenkung veranschaulicht. Dabei ist der Winkel der Innenfase konstant, während der Winkel der Außenfase drei verschiedene Werte annimmt. So kann bezogen auf die Mantelfläche der Winkel der Innenfase sehr steil sein und bis zu 90° betragen, also nahezu oder ganz in Radialrichtung verlaufen, während die Außenfase einen Winkel von etwa 75° aufweist. Der Übergang zwischen den Fasen kann als Kante oder abgerundet ausgebildet sein. Die Figur 2 zeigt zwei Kurvenscharen, die die Kennlinien für einen Volumenstrom von 2 Litern pro Minute (mit 1 bezeichnet) und für 9 1/min (mit 2 bezeichnet) wiedergeben. Aufgetragen ist das eingeleitete Handmoment (x-Achse) an der Lenksäule bzw. am Drehschieberventil gegenüber dem aufgebauten Druck, der an dem zugeordneten hydraulischen Arbeitsraum der Servolenkung ansteht auf der y-Achse.1 shows the geometry of the inner chamfer and outer chamfer in three variants with a control groove of a power steering system according to the invention. The angle of the inner chamfer is constant, while the angle of the outer chamfer assumes three different values. The angle of the inner chamfer can be very steep with respect to the lateral surface and can be up to 90 °, that is to say run almost or completely in the radial direction, while the outer chamfer has an angle of approximately 75 °. The transition between the chamfers can be designed as an edge or rounded. FIG. 2 shows two sets of curves which represent the characteristic curves for a volume flow of 2 liters per minute (denoted by 1) and for 9 1 / min (denoted by 2). The manual torque (x-axis) introduced is plotted on the steering column or on the rotary slide valve against the pressure built up on the associated hydraulic work space of the power steering system on the y-axis.
Es ist ersichtlich, dass der für eine Servounterstützung typische Arbeitsdruck von 20 bar bei 9 1/min einem Handmoment von 2,5 nm entspricht, und zwar im wesentlichen unabhängig von der Geometrie der Außenfase. Bis zu diesem Punkt ist der Druckaufbau ausschließlich an der Innenfase erfolgt.It can be seen that the typical working pressure of 20 bar at 9 1 / min for servo assistance corresponds to a manual torque of 2.5 nm, and essentially independent of the geometry of the outer chamfer. Up to this point, the pressure has only been built up on the inner chamfer.
Bei 2 1/min ist der Druck von 20 bar je nach Neigung der Außenfase bei 3,4 bis 4,2 nm erreicht. Die drei Kennlinien fal- len hier bereits bei wesentlich geringerem Handmoment auseinander. Der Druckaufbau wird hier von der Geometrie der Außenfase bestimmt.At 2 1 / min the pressure of 20 bar is reached at 3.4 to 4.2 nm depending on the inclination of the outer chamfer. The three characteristic lines already fall apart at a much lower hand torque. The pressure build-up is determined here by the geometry of the outer chamfer.
Mit dieser Gestaltung der Innenfase und der Außenfase ist also eine Abhängigkeit der Kennlinie von dem verfügbaren Volumen- ström möglich. Die Spreizung der Kennlinien (Abstand zwischen der 2 1/min-Linie von der 9 1/min-Linie) ist um so größer, je größer der Winkelunterschied der Fasen ist.With this design of the inner chamfer and the outer chamfer, a dependency of the characteristic curve on the available volume flow is possible. The spread of the characteristic curves (distance between the 2 1 / min line from the 9 1 / min line) is greater, the greater the angle difference of the chamfers.
Für eine Parametrisierung der Lenkung beispielsweise für eine geschwindigkeitsabhängige Servounterstützung kann nun in ein- facher Weise die Förderleistung der Servopumpe in Abhängigkeit von Fahrzustandsparameter (Geschwindigkeit etc.) gesteuert oder geregelt werden.For a parameterization of the steering, for example for a speed-dependent servo support, the delivery rate of the servo pump can now be controlled or regulated in a simple manner depending on the driving state parameters (speed, etc.).
Eine besonders große Spreizung ist durch folgende Merkmale erreichbar:A particularly large spread can be achieved by the following features:
Die Innenfase und die Außenfase weisen unterschiedliche Neigungswinkel auf, wobei der Übergang als Kante oder Rundung ausgeführt sein kann. Die Neigung der Innenfase bezüglich der Umfangsrichtung des Drehschiebers kann bis zu 90° betragen.The inner chamfer and the outer chamfer have different angles of inclination, and the transition can be designed as an edge or rounding. The inclination of the inner chamfer with respect to the circumferential direction of the rotary valve can be up to 90 °.
Der Winkelunterschied soll möglichst groß sein, so dass die Innenfase möglichst schnell schließt, während die Außenfase möglichst langsam schließt.The angle difference should be as large as possible so that the inner chamfer closes as quickly as possible, while the outer chamfer closes as slowly as possible.
Die Innenfase soll die Kennlinie im Bereich von 20 bis 30 bar Servodruck bei großem Volumenstrom bestimmen.The inner chamfer should determine the characteristic in the range of 20 to 30 bar servo pressure with a large volume flow.
Die Außenfase soll die Kennlinie im Bereich von 20 bis 30 bar Servodruck bei geringem Volumenstrom bestimmen. The outer chamfer should determine the characteristic in the range of 20 to 30 bar servo pressure with a low volume flow.

Claims

P a ten tan sp rü che P a ten tan speech
1. Hydraulische Servolenkung für Kraftfahrzeuge mit einem hydraulischen Servomotor, einem Drehschieberventil mit Steuernuten und Steuerkanten, sowie mit einer Servopumpe, die dazu eingerichtet ist, im Betrieb wenigstens zwei verschiedene Volumenströme eines Hydraulikfluids zur Verfügung zu stellen, dadu r ch ge kenn z e i chne t , daß die Steuerkanten eine Innenfase und eine Außenfase unterschiedlicher Neigung aufweisen.1.Hydraulic power steering for motor vehicles with a hydraulic servo motor, a rotary slide valve with control grooves and control edges, and with a servo pump which is set up to make available at least two different volume flows of a hydraulic fluid during operation, so that it is characterized, that the control edges have an inner chamfer and an outer chamfer of different inclinations.
2. Servolenkung nach Anspruch 1, dadur ch ge ke nn z e i chne t , daß die Steuerkanten im Bereich der Innen- und Außenfasen konvex ausgebildet sind.2. Power steering according to claim 1, so that the control edges are convex in the area of the inner and outer chamfers.
3. Servolenkung nach Anspruch 1 oder 2, dadu r ch ge kenn z e i chne t , daß die Innenfase bezüglich der Umfangsrichtung einen Winkel von 85° bis 90° und die Außenfase einen Winkel von 70° bis 80° aufweist.3. Power steering according to claim 1 or 2, so that the inner chamfer has an angle of 85 ° to 90 ° with respect to the circumferential direction and the outer chamfer has an angle of 70 ° to 80 °.
4. Servolenkung nach einem der vorhergehenden Ansprüche, dadur ch geke nn z e i chne t , daß eine Steuerung zur geschwindigkeitsabhängigen Steuerung des Fördervolumens der Servopumpe vorgesehen und mit der Servolenkung elektrisch verbunden ist. 4. Power steering according to any one of the preceding claims, that ch geke nn z e i chne t that a controller for speed-dependent control of the delivery volume of the servo pump is provided and is electrically connected to the power steering.
PCT/EP2004/008684 2003-08-22 2004-08-03 Rotary disk valve comprising control edges and control grooves for use in power-assisted steering systems with variable hydraulic volume flow WO2005021358A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10339202.5 2003-08-22
DE2003139202 DE10339202A1 (en) 2003-08-22 2003-08-22 Steering gear for a motor vehicle

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59128051A (en) * 1983-01-07 1984-07-24 Toyoda Mach Works Ltd Rotary servo valve
US5048630A (en) * 1990-04-09 1991-09-17 Ford Motor Company Power steering trim control system
US5439070A (en) * 1992-06-12 1995-08-08 Toyoda Koki Kabushiki Kaisha Hydraulic power steering apparatus
JPH08216905A (en) * 1995-02-10 1996-08-27 Kayaba Ind Co Ltd Power steering device
JP2002046635A (en) * 2000-08-07 2002-02-12 Koyo Seiko Co Ltd Power steering device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59128051A (en) * 1983-01-07 1984-07-24 Toyoda Mach Works Ltd Rotary servo valve
US5048630A (en) * 1990-04-09 1991-09-17 Ford Motor Company Power steering trim control system
US5439070A (en) * 1992-06-12 1995-08-08 Toyoda Koki Kabushiki Kaisha Hydraulic power steering apparatus
JPH08216905A (en) * 1995-02-10 1996-08-27 Kayaba Ind Co Ltd Power steering device
JP2002046635A (en) * 2000-08-07 2002-02-12 Koyo Seiko Co Ltd Power steering device

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 0082, no. 53 (M - 339) 20 November 1984 (1984-11-20) *
PATENT ABSTRACTS OF JAPAN vol. 1996, no. 12 26 December 1996 (1996-12-26) *
PATENT ABSTRACTS OF JAPAN vol. 2002, no. 06 4 June 2002 (2002-06-04) *

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