[go: up one dir, main page]

WO2005080177A1 - Valve de direction assistee pour une direction assistee de vehicule - Google Patents

Valve de direction assistee pour une direction assistee de vehicule Download PDF

Info

Publication number
WO2005080177A1
WO2005080177A1 PCT/EP2005/001625 EP2005001625W WO2005080177A1 WO 2005080177 A1 WO2005080177 A1 WO 2005080177A1 EP 2005001625 W EP2005001625 W EP 2005001625W WO 2005080177 A1 WO2005080177 A1 WO 2005080177A1
Authority
WO
WIPO (PCT)
Prior art keywords
power steering
steering valve
valve according
piston
output element
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/EP2005/001625
Other languages
German (de)
English (en)
Inventor
Hans-Dieter Heitzer
Christoph Eicker
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.)
ZF Automotive Germany GmbH
Original Assignee
TRW Automotive 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
Priority claimed from DE200410007619 external-priority patent/DE102004007619A1/de
Application filed by TRW Automotive GmbH filed Critical TRW Automotive GmbH
Publication of WO2005080177A1 publication Critical patent/WO2005080177A1/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
    • B62D5/08—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
    • B62D5/0835—Rotary valves characterised by means for actively influencing the deflection angle of the valve, e.g. depending on driving parameters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/006—Hydraulic "Wheatstone bridge" circuits, i.e. with four nodes, P-A-T-B, and on-off or proportional valves in each link

Definitions

  • the invention relates to a power steering valve with an input element and an output element, which are adjustable relative to one another starting from a central position in order to provide a fluid flow for steering assistance.
  • Such a power steering valve is a central component of a hydraulic power steering, by means of which a steering support force can be provided.
  • a power steering system can be found in European patent application 0 551 619.
  • the input element is designed as an input shaft, which is connected to a steering wheel
  • the output element is designed as a control sleeve, which is connected to a steering gear.
  • the input shaft and the control sleeve are each provided with control grooves, by means of which a hydraulic flow through the power steering valve can be controlled.
  • a hydraulic current provided by a pump is distributed uniformly over two outputs of the power steering valve.
  • one of the outputs is more strongly supplied with the hydraulic current.
  • This hydraulic flow can be conducted to one side of a hydraulic cylinder, for example, so that a steering assist force is generated in a first direction.
  • the steering support arm is generated in the opposite direction.
  • the object of the invention is to develop a power steering valve of the type mentioned in such a way that a steering pulse can be generated actively with little effort.
  • an actuator is provided according to the invention, which in
  • the invention is arranged inside the power steering valve and can rotate the input element and the output element relative to each other out of the central position.
  • the invention is based on the basic idea of generating the additional steering impulse directly inside the power steering valve by producing a steering assistance force in the corresponding direction. In this way it is possible to dispense with superimposition gears arranged outside the steering gear, which introduce the additional steering impulse between the steering wheel and the steering gear.
  • the particular advantage of the solution according to the invention is that it can be implemented hydraulically, so that it can be integrated into existing hydraulic power steering systems with little effort.
  • the actuator has two axially displaceable pistons which act on balls which in turn are supported on a support disk.
  • the use of balls leads to particularly low friction when actuating the actuator.
  • the required travel of the pistons can also be reduced by a suitably steep inclination of the surfaces on which the balls are supported, so that a compact design results.
  • the actuator has a double-acting adjusting piston which is coupled to both the control sleeve and the input shaft.
  • the control sleeve is rotated relative to the input shaft by axial displacement of the actuating piston, so that a steering pulse can be actively generated.
  • FIG. 1 shows a power steering gear with a power steering valve according to the invention
  • FIG. 2 is a schematic view of the power steering valve according to a first
  • FIG. 3 schematically shows the power steering valve of Figure 2 with a hydraulic circuit according to a first variant.
  • FIG. 4 schematically shows the power steering valve of Figure 2 with a hydraulic circuit according to a second variant
  • FIG. 5 schematically shows a section through a power steering valve according to a second embodiment
  • FIG. 6 schematically shows a section along the plane VI-VI of Fig. 5;
  • FIG. 7 schematically shows the power steering valve of Figure 5 with a hydraulic circuit
  • FIG. 9 schematically shows the torque exerted on the input shaft when a second pressure chamber is pressurized
  • - Figure 10 is a schematic view of a power steering valve according to a third embodiment
  • FIG. 12 schematically shows a hydraulic circuit for the power steering valve of Figure 10.
  • a steering gear 2 is shown, which has an input shaft 3, which is connected to a steering wheel 4.
  • the input shaft 3 is part of a power steering valve 5 which has an output shaft 6.
  • a pinion 7 is arranged on this, which engages in a rack 8 which is adjustably mounted in the steering gear 2.
  • the rack 8 is coupled to steerable vehicle wheels 9, so that rotation of the steering wheel 4 is converted into a pivoting movement of the wheels 9.
  • the power steering valve considered here is a hydraulic power steering valve, the basic structure of which is known, for example, from US Pat. No. 4,819,545. Reference is expressly made to this document in its entirety.
  • the power steering valve 5 is shown schematically.
  • the input shaft 3 is provided on its outer surface with control grooves which cooperate with control grooves on the inside of a control sleeve 10 which is connected to the output shaft 6 in a rotationally fixed manner.
  • a hydraulic current can be provided by the control grooves, which hydraulic current is converted into a steering assist force. This is generally known in the field of hydraulic power steering systems, so that it will not be discussed further here.
  • Centering is provided, which consists of a first centering disk 12, a second centering disk 14 and centering balls 16.
  • the first centering disc 12 is fixed to the input shaft 3.
  • the second centering disk 14 is non-rotatably connected to the control sleeve 10, but can be shifted slightly in the axial direction relative to the longitudinal axis L of the power steering valve.
  • a ball guide 18 is provided for this purpose.
  • Each of the two clamping disks has a recess 20 on each of the opposite end faces, between which a centering ball 16 is received.
  • a centering spring 22 acts on the side of the second centering disk 14 facing away from the first centering disk 12 and is supported on a closure element 24.
  • the closure element 24 is firmly attached to the interior of the power steering valve 5. Between the closure element 24 and the second centering disk 14 is a Zentrierka mer 26 is formed, which is acted upon via a pressure port 28 with a variable, controlled pressure.
  • the first centering disk 12 and the second centering disk 14 are arranged such that their starting position shown in FIG. 2 corresponds to the starting position of the input shaft 3 relative to the control sleeve 10; in other words, the neutral center position of the power steering valve 5 also corresponds to the center position of the centering disk 12 relative to the centering disk 14.
  • the second centering disk 14 must be pushed away from the first centering disk 12 in the direction of arrow P.
  • An An ⁇ -h ⁇ c-d-raft must be overcome, which is composed of the force exerted by the centering spring 22 and the force exerted on the second centering disk 14 by the pressure in the centering chamber 26.
  • the greater this pressing force the greater the steering torque exerted on the input shaft 3 in order to generate a predetermined steering support force by relatively rotating the input shaft 3 relative to the control sleeve 10. This is also known in principle from the prior art.
  • the power steering valve 5 is provided with an actuator 30, which acts in exactly the opposite direction as the centering.
  • the actuator 30 enables the input shaft 3 to be rotated relative to the control sleeve 10 out of the center position, which is predetermined by the centering.
  • the actuator 30 has an output element in the form of a support disk 32 which is fixedly connected to the input shaft 3.
  • the support disk has a plurality of support surfaces 34 on each of its sides, which are oriented obliquely to a plane perpendicular to the longitudinal axis L.
  • a piston 36 which is part of a drive assembly, is arranged on each side of the support disk 32.
  • Each piston 36 is rotatably connected to the control sleeve 10, but can be moved in the axial direction, that is, along the longitudinal axis L, inside the power steering valve 5 and thus relative to the support disk 32.
  • guide balls 38 are provided, which engage in grooves in both the piston 36 and in the control sleeve 10 and in this way enable the displacement in the longitudinal direction, but bring about a rotationally fixed connection with the control sleeve 10.
  • Each piston 36 is provided on its end face facing the support disk 32 with a plurality of pressure surfaces 40 which lie opposite the support surfaces 34 on the support disk 32.
  • the pressure surfaces 40 are also arranged obliquely to a plane that is perpendicular to the longitudinal axis L.
  • a ball 42 is arranged between each of the pressure surfaces 40 and the support surfaces 34.
  • the balls on each side of the support disk 32 are connected to one another by a ball holder 44.
  • a compression spring 46 acts on each rear side of each piston 36 facing away from the support disk 32.
  • the other end of each compression spring is supported on the closure element 24 or a closure cover 48.
  • a pressure chamber 50 or 50 ' is formed which can be acted upon by a variable, controlled pressure via a pressure connection 52 or 52'. In the initial state, the same prevails in the two drain chambers 50, 50 '
  • a hydraulic circuit for controlling the actuator 30 is shown schematically in FIG. 3.
  • a motor 54 is provided which drives a hydraulic pump 56.
  • a pressure accumulator 58 is also provided.
  • a shutoff valve 60 is arranged between the hydraulic pump 56 and the actuator 30, which connects the two drain chambers 50, 50 ′ to a reservoir 62 in the initial state.
  • the two pressure valves 50, 50 * are thus at the same low pressure level in the initial state.
  • a directional valve 64 is provided, by means of which it can be controlled which of the two pressure chambers 50, 50 'is pressurized.
  • the shut-off valve 60 must first be actuated so that there is a connection between the hydraulic pump 56 and the actuator 30 at all.
  • the directional valve 64 can remain in its initial position. In this way, the hydraulic pressure provided by the hydraulic pump 56 is directed to the right pressure chamber 50. The level of the hydraulic pressure conducted to the corresponding pressure chamber is controlled via the speed of the motor 54.
  • the directional valve 64 is switched so that the hydraulic pressure generated by the hydraulic pump 56 is led to the left drack chamber 50'.
  • the switch-off valve 60 is brought back into its initial state, so that the two drain chambers 50, 50 'are vented to the reservoir 62.
  • FIG. 1 Another variant of the hydraulic circuit is shown in FIG.
  • a bidirectional pump is used, which is operated in one direction or the other, depending on the pressure chamber 50 to be pressurized.
  • the level of the pressure passed to the corresponding drain chamber 50 can be controlled via the engine speed.
  • an actuator 30 according to a second embodiment is shown schematically.
  • the same reference numerals are used for the components known from the first embodiment, and reference is made to the above explanations in this regard.
  • the actuator 30 has in the second embodiment in each Dracdcarnmer
  • each piston 36 bears with its end face facing away from the drain chamber 50 or 50 ′ against a projection 72 which is formed in one piece with the input shaft 3.
  • FIG. 7 schematically shows a hydraulic circuit with which the actuator 30 can be controlled in accordance with the second embodiment.
  • a unidirectional hydraulic pump 56 is used, with a pressure relief valve 74 and a pressure sensor 76 additionally being provided.
  • a control unit 78 is provided which is connected to the drain sensor 76 and controls the motor 54, the drain relief valve 74 and a total of four switching valves 80, 82, 84, 86.
  • the two drain chambers 50, 50 ′ are isolated from the hydraulic pump 56 by means of the two switching valves 80, 84. At the same time, the two pressure chambers are vented to the reservoir 62 via the switching valves 82 and 86.
  • the two switching valves 80, 82 are actuated. As a result, the drain chamber 50 is connected to the pressure side of the hydraulic pump 56, while the connection to the reservoir 62 is closed.
  • the hydraulic pressure then acting on the pistons 36 leads to a reaction moment (see arrow M) by means of which the control sleeve 10 is acted on counterclockwise relative to the input shaft 3.
  • FIG. 10 shows a power steering valve according to a third embodiment.
  • the same reference numerals are used for the components known from the first and second embodiments, and reference is made to the above explanations in this respect.
  • the piston 36 is designed here as a double-acting control piston, so that the Drac-dca mern 50, 50 'are immediately delimited from each other by the piston 36.
  • the piston 36 is arranged as an annular piston on the input shaft 3 and connected to it in a rotationally fixed but axially displaceable manner.
  • a groove 90 (FIG. 11) is provided on the input shaft 3, into which a web 92 on the piston 36 can engage.
  • a spline profile, a polygon profile or another design can be used, which enables the piston 36 to be axially displaceable.
  • the piston 36 is formed by a plurality of link guides. These each consist of a guide link 94 on the piston 36, in which a pin 96 engages, which is fixedly attached to a projecting collar 98 of the control sleeve 10.
  • the guide links 94 are oriented at an angle ⁇ relative to the longitudinal axis of the input shaft 3. The size of the angle can be selected depending on design parameters.
  • the hydraulic pump 56 generates a hydraulic flow that flows through the hydraulic servo valve with an open center position.
  • this hydraulic flow is supplied to the two chambers of a hydraulic cylinder 100 either symmetrically or asymmetrically. In this way, a steering assist force can be generated in one direction or the other.
  • the return line 102 from the power steering valve 5 branches. One branch leads to the reservoir 62 via a controllable throttle 104. The other branch leads to the actuator 30 via a drain sensor 106 and a control valve 108.
  • the control valve 108 is a 4/3-way valve which is controlled by a control unit 78.
  • the control unit 78 also controls the throttle 104.
  • external data D which can, for example, indicate the steering angle, the steering angle speed, the steering torque, the vehicle speed, the yaw rate, the lateral acceleration or the brake pressure
  • the control unit 78 also receives an input signal from Pressure sensor 106.
  • the control valve 108 In the initial state, when no steering overlay is desired, the control valve 108 is in a position in which the two pressure chambers 50, 50 'are freely connected to one another. At the same time, the throttle 104 is opens so that the piston 36 is not pressurized. So he can adjust freely. Therefore, when the input shaft 3 is rotated, the piston rotates freely between the two pressure chambers 50, 50 '.
  • the steering assistance generated depends solely on the torque that acts between the input shaft 3 and the output shaft 6 and causes the input shaft to rotate relative to the control sleeve. Since the two Drackk-50, 50 'are freely connected to each other, the piston 36 is axially adjusted relative to the control sleeve when the input shaft is rotated.
  • control unit 78 controls the control valve 108 in such a way that one of the two pressure chambers 50, 50 ′ is pressurized, while the other is connected to the reservoir 62 via a return line.
  • the throttle 104 is closed, so that a pressure builds up in the return line 102.
  • the resulting pressure for example in the drain chamber 50, moves the piston 36 to the right in relation to FIGS. 10 and 11, as a result of which the pin 96 is moved downward by the guide link 94.
  • the particular advantage of the third embodiment is that no additional spring is required for centering.
  • the input shaft and the output shaft are reset to their neutral position under the action of the torsion bar.
  • the piston 36 is automatically returned to its starting position via the guide 94, 96.
  • the throttle 104 and the control valve 108 are designed in such a way that, if they are not actuated by the control unit 78, they are automatically reset to an initial state in which the throttle is open and the two drackck valves 50, 50 'are free from one another are connected.
  • variable steering assistance can be generated. This can depend on the vehicle speed, for example. At a low vehicle speed, a comparatively high steering assistance is provided, so that, for example, parking is made easier. At higher speeds, the steering assistance is reduced in order to have a more direct steering feeling.
  • the steering characteristic can be influenced by changing the resistance that counteracts rotation of the input shaft relative to the output shaft. This can be done by suitable control of the piston 36.
  • the piston 36 can generate a force that increases the resistance moment provided by the torsion bar or reduces it in the opposite manner.
  • Another operating mode is to control the piston for a certain, usually short period of time so that a short steering pulse is generated in the steering wheel.
  • This steering impulse signals a driver in which direction the steering wheel should be turned, for example in order to restore driving stability in a critical vehicle state.
  • the necessary pressure difference can be easily set using the throttle 104, the pressure sensor 106 and the control unit 78.
  • Another operating mode is automatic parking.
  • the axial displacement of the piston is used to rotate the input shaft and the output shaft relative to one another to such an extent that the servo valve 5 and the hydraulic cylinder 100 generate such a high support force that the steerable vehicle wheels are turned without actuating the steering wheel.
  • Automatic parking of the vehicle can be carried out together with other control units.
  • the control unit 78 ensures that the torques that occur remain so low that there is no risk of injury to a driver accidentally reaching into the steering wheel during automatic parking.

Landscapes

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

Abstract

L'invention concerne une valve de direction assistée pourvue d'un élément d'entrée (3) et d'un élément de sortie (10), pouvant être pivotés l'un par rapport à l'autre à partir d'une position centrale pour fournir un flux de fluide à l'assistance directionnelle. Cette invention se caractérise en ce qu'un actionneur (30) est installé à l'intérieur de cette valve de direction assistée et lesdits éléments d'entrée et de sortie peuvent pivoter l'un par rapport à l'autre à partir de ladite position centrale.
PCT/EP2005/001625 2004-02-17 2005-02-17 Valve de direction assistee pour une direction assistee de vehicule Ceased WO2005080177A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE102004007619.7 2004-02-17
DE200410007619 DE102004007619A1 (de) 2004-02-17 2004-02-17 Servolenkventil
DE202004013834U DE202004013834U1 (de) 2004-02-17 2004-09-06 Servolenkventil für eine Fahrzeug-Servolenkung
DE202004013834.4 2004-09-06

Publications (1)

Publication Number Publication Date
WO2005080177A1 true WO2005080177A1 (fr) 2005-09-01

Family

ID=34888791

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2005/001625 Ceased WO2005080177A1 (fr) 2004-02-17 2005-02-17 Valve de direction assistee pour une direction assistee de vehicule

Country Status (1)

Country Link
WO (1) WO2005080177A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0375136A2 (fr) * 1988-12-22 1990-06-27 General Motors Corporation Appareil électromagnétique de contrôle pour faire varier l'effort de direction du conducteur dans un appareil de direction assisté hydrauliquement
DE4003981A1 (de) * 1989-02-10 1990-08-23 Mitsubishi Motors Corp Lenkgetriebeverhaeltnis-wechselvorrichtung
US5771989A (en) * 1996-02-28 1998-06-30 Trw Inc. Power steering system
US5842536A (en) * 1997-06-02 1998-12-01 General Motors Corporation Power steering gear for motor vehicle

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0375136A2 (fr) * 1988-12-22 1990-06-27 General Motors Corporation Appareil électromagnétique de contrôle pour faire varier l'effort de direction du conducteur dans un appareil de direction assisté hydrauliquement
DE4003981A1 (de) * 1989-02-10 1990-08-23 Mitsubishi Motors Corp Lenkgetriebeverhaeltnis-wechselvorrichtung
US5771989A (en) * 1996-02-28 1998-06-30 Trw Inc. Power steering system
US5842536A (en) * 1997-06-02 1998-12-01 General Motors Corporation Power steering gear for motor vehicle

Similar Documents

Publication Publication Date Title
DE60307161T2 (de) Aktives Vorderrad-Lenkungs-Stellglied und Verfahren zum Steuern eines Fahrzeugs
DE102013014133B3 (de) Lenkanschlag
EP3036147B1 (fr) Butée de direction
DE2511176A1 (de) Lenkeinrichtung fuer ein fahrzeug mit differenzgeschwindigkeitslenkung
DE1155987B (de) Lenkgetriebe mit veraenderlichem UEbersetzungsverhaeltnis
DE112011101996T5 (de) Steuerbares Lenkzahnstangenführungssystem und -verfahren
DE2528094A1 (de) Steuersystem fuer hydrostatische getriebe
DE102006052660B4 (de) Lenkvorrichtung
DE10159330A1 (de) Reaktionsmomentsimulator für ein Lenkrad einer Fahrzeuglenkung
DE19519875C1 (de) Hydraulische Servosteuerung, insbesondere Servolenkung für Kraftfahrzeuge
DE19842624B4 (de) Verfahren zum Betreiben eines Lenksystems für ein Fahrzeug
DE4138885A1 (de) Servolenkung, insbesondere fuer kraftfahrzeuge
DE4422385C2 (de) Hydraulische Servolenkung
DE2710849C2 (de) Hilfskraftlenkung für Fahrzeuge mit Rückführung
DE202005018390U1 (de) Ventilvorrichtung für eine hydraulische Servolenkung
DE202004013834U1 (de) Servolenkventil für eine Fahrzeug-Servolenkung
DE2104037C3 (de) Servolenksystem
DE4023943A1 (de) Servobremsanlage fuer ein kraftfahrzeug
DE3731256A1 (de) Drehschieberventil fuer hydraulische hilfskraftlenkungen
DE4113617A1 (de) Hilfskraftlenkanlage
WO2005080177A1 (fr) Valve de direction assistee pour une direction assistee de vehicule
EP2222531A1 (fr) Servosoupape pour une direction assistee hydraulique
DE10253468A1 (de) Servolenkung mit Rangier-Betriebsweise
EP0983182A1 (fr) Systeme de retroaction sur un systeme de servo-valve
DE69019276T2 (de) Servolenkeinrichtung.

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): BW GH GM KE LS MW MZ NA SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: DE

WWW Wipo information: withdrawn in national office

Country of ref document: DE

122 Ep: pct application non-entry in european phase