EP1713678A1 - Systeme de direction de vehicule - Google Patents

Systeme de direction de vehicule

Info

Publication number
EP1713678A1
EP1713678A1 EP05716646A EP05716646A EP1713678A1 EP 1713678 A1 EP1713678 A1 EP 1713678A1 EP 05716646 A EP05716646 A EP 05716646A EP 05716646 A EP05716646 A EP 05716646A EP 1713678 A1 EP1713678 A1 EP 1713678A1
Authority
EP
European Patent Office
Prior art keywords
hydraulic
steering
valve
pressure
vehicle
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Withdrawn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
EP05716646A
Other languages
German (de)
English (en)
Inventor
Peter Rieth
Jürgen Böhm
Johann Jungbecker
Steffen Linkenbach
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.)
Continental Teves AG and Co OHG
Original Assignee
Continental Teves AG and Co OHG
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 Continental Teves AG and Co OHG filed Critical Continental Teves AG and Co OHG
Publication of EP1713678A1 publication Critical patent/EP1713678A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/021—Valves for interconnecting the fluid chambers of an actuator
    • 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
    • B62D5/09—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 means for actuating valves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
    • B62D6/08—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits responsive only to driver input torque
    • 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
    • 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
    • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
    • F15B20/008—Valve failure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20507—Type of prime mover
    • F15B2211/20523—Internal combustion engine
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
    • F15B2211/30575—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve in a Wheatstone Bridge arrangement (also half bridges)
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed centre
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3144—Directional control characterised by the positions of the valve element the positions being continuously variable, e.g. as realised by proportional valves
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/3157—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line
    • F15B2211/31576—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line having a single pressure source and a single output member
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/327—Directional control characterised by the type of actuation electrically or electronically
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6313—Electronic controllers using input signals representing a pressure the pressure being a load pressure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6336—Electronic controllers using input signals representing a state of the output member, e.g. position, speed or acceleration
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6346—Electronic controllers using input signals representing a state of input means, e.g. joystick position
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/765—Control of position or angle of the output member

Definitions

  • the invention relates to a vehicle steering system for motor vehicles, with a steering handle which can be actuated by the driver and an actuating unit which is assigned to the steered vehicle wheels and is operatively connected to the steering handle and by means of which, if appropriate, further elements, such as e.g. Tie rods and track levers, the steered vehicle wheels can be pivoted to set a desired steering angle and which actuating unit is a hydraulic unit, with two hydraulic chambers which are separated by a hydraulic piston and can be acted upon by the pressure of a hydraulic pressure source.
  • the invention has for its object to provide a vehicle steering system of the type mentioned, with which an effective steering angle control with high functional reliability is achieved.
  • the invention solves this problem by providing vehicle steering with the features of the independent claim.
  • the hydraulic unit can be connected to the hydraulic pressure source or a pressure medium reservoir via a valve unit, and that steering assistance can be set by means of the valve unit.
  • the valve unit has a hydraulic slide valve, by means of which steering assistance is regulated by continuously adjusting a pressure difference between the two hydraulic chambers. This constant controllability of the slide valve in the sense of a "hydraulic full bridge" ensures a particularly comfortable setting of the support pressure.
  • the valve unit is a continuously adjustable slide valve with three switching end positions, with a first switching end position in which a pressure medium can be introduced into the two hydraulic chambers and / or can be led out of the two hydraulic chambers, so that the pressure difference between the two hydraulic chambers is 0 (ZERO), with a second switching end position in which the pressure medium can be introduced into a first hydraulic chamber and can be led out of a second hydraulic chamber, and with a third switching end position in which the pressure medium can be led out of the first hydraulic chambers and can be introduced into the second hydraulic chamber for the purpose of regulating a maximum support pressure.
  • the hydraulic slide valve can be continuously adjusted between the different switching positions by an electric actuator, preferably via a servo drive and possibly a gear or an electromagnet, by means of a linear movement of a valve slide.
  • a linear movement or “adjusting movement” of the valve spool is generated by the electrical actuator, as a result of which the valve spool can be brought into “any” sliding positions, so that continuous pressure regulation takes place.
  • a displacement sensor is provided for the hydraulic slide valve, by means of which the linear movement of the valve slide is detected.
  • the hydraulic slide valve has control edges, by means of which a pressure difference between the two hydraulic chambers is continuously set during a linear movement of the valve slide.
  • the control edges have a special design so that a harmonious pressure boosting function and good control behavior for steering assistance is achieved.
  • Valve unit alternatively has at least four analogized valves, preferably 2 normally closed (SG) and two normally open (SO) analog valves or analog controllable valves, for the purpose of regulating the pressure in the two hydraulic chambers.
  • analogized valves preferably 2 normally closed (SG) and two normally open (SO) analog valves or analog controllable valves, for the purpose of regulating the pressure in the two hydraulic chambers.
  • a safety valve is provided, by means of which the two hydraulic chambers can be connected directly to one another. This allows the chambers to be connected directly in the event of a fault, so that a closed hydraulic circuit is created, which means that the wheels are directly, i.e. in this case without support, can be operated.
  • a hydraulic slide valve is provided as a safety valve, which can be switched into different switching positions by means of 2 hydraulic valves by a linear movement of a safety valve switching element.
  • two hydraulic pressure sensors are provided, by means of which the hydraulic pressure in the two hydraulic chambers is recorded, and it is provided that steering assistance can be set in accordance with the recorded pressures.
  • a torque sensor which detects the torque on a steering wheel shaft of the vehicle steering system. It is provided that steering assistance can be set taking into account the detected torque.
  • the steering is an open center steering ("open center steering"), in which in a zero position of the steering, ie the steering wheel in the straight ahead position, there is essentially no pressure difference between the chambers separated by the hydraulic pistons and that the hydraulic pressure source has a pump which is connected to the drive motor of the vehicle via a drive, preferably a belt drive.
  • open center steering in which in a zero position of the steering, ie the steering wheel in the straight ahead position, there is essentially no pressure difference between the chambers separated by the hydraulic pistons and that the hydraulic pressure source has a pump which is connected to the drive motor of the vehicle via a drive, preferably a belt drive.
  • the steering is a closed center steering ("closed center steering"), in which in a zero position of the steering, ie the steering wheel in the straight ahead position, essentially a hydraulic pressure or a pressure difference in the hydraulic pistons separate chambers can exist, and that the hydraulic pressure source has a pump which can be connected to the vehicle drive via a clutch and a drive, preferably a belt drive.
  • the hydraulic pressure source has a high-pressure accumulator and that the pump is operated in order to charge the high-pressure accumulator.
  • a hydraulic pressure sensor is provided, the hydraulic pressure in the high-pressure accumulator being determined using the pressure sensor.
  • the analog valves or analog valves which are preferred for the vehicle steering system according to the invention are proportional valves. These are in particular proportionally controlled or operated solenoid valves or piezo valves.
  • seat valves e.g. 2/2-way poppet valves with two inputs and / or outputs are used, the inputs and outputs being connected to one another in one (open) switching position and separated from one another in the other (closed) switching position.
  • the solenoid valves are opened and closed by activating or deactivating a magnet provided in the valve.
  • the activation of the magnet i.e. the energization of the coil, results in the movement, more precisely the pulling or releasing of an armature, which is connected to the locking mechanism of the valve and thereby moves it.
  • valves are operated such that the locking mechanism assumes an intermediate position between the switching positions, or they are opened or closed in quick succession for the same or different lengths, so that a state corresponding to a stationary intermediate position of the locking mechanism is established.
  • a setting of the valve allows a defined differential pressure to be set across the valve in the vehicle steering system according to the invention.
  • the steering according to the invention can in principle also pivot the steerable wheels independently of the driver, for example in order to react faster and better (than the driver) to recognized emergency situations, such as vehicle instabilities.
  • Comfort functions such as a necessary steering force depending on the vehicle speed, can be easily implemented in the sense of parameter steering.
  • Fig. 1 shows a steering system with a hydraulic
  • Fig. 2 shows an embodiment of a steering system with an open center according to the invention with a valve unit
  • Linear slide valve (servo valve), safety valve and:. two pressure sensors.
  • FIG 3 shows a further embodiment of a steering system with an open center according to the invention with a displacement sensor on the actuator of a linear slide valve of the valve unit.
  • Fig. 4 shows an embodiment of a steering system with an open center according to the invention with a valve unit with four analog valves.
  • Fig. 5 shows an embodiment of a closed center steering system according to the invention with a valve unit with four analog valves and a high pressure accumulator.
  • Fig. 6 shows the valve unit according to the invention with a linear slide valve and a safety valve in the closed switching position in a schematic representation.
  • Fig. 7 shows the valve unit shown in Fig. 8 in a cross section.
  • Fig. 8 shows the valve unit according to the invention with a linear slide valve and a safety valve in the open switch position in a schematic representation.
  • FIG. 9 shows the valve unit shown in FIG. 10 in a cross section.
  • the steering system shown in Fig. 1 consists of a steering wheel 1, a steering column 2 connected to the steering wheel 1 with 2 universal joints 3, 4.
  • the steering column 2 is connected or part of a steering wheel shaft 5, which is formed via a steering gear 6, a steering rod 7, here as a rack 7, which actuates tie rods 8, 9 attached to the side of the rack 7, and thereby a pivoting of the wheels 10, rll causes.
  • hydraulic assistance is provided by means of a drive motor of the vehicle, e.g. Realized via a belt drive 12, driven hydraulic pump 13, which supplies pressurized hydraulic fluid to a steering valve 14 via a line 15.
  • the pressure fluid can flow back into a reservoir 17 through a return line 16.
  • the rack 7 When the steering wheel 1 is rotated, the rack 7 is displaced via the torsion bar 80 and the steering gear 6. The movement of the piston 21 is supported by the pressure of the hydraulic fluid.
  • the valve 14 causes hydraulic fluid to flow from one chamber to the other chamber, so that the steering actuation receives hydraulic assistance.
  • the actuation of the steering wheel 1 can be measured by a steering angle sensor 22 and its signal can preferably be transmitted to an electronic unit via a vehicle bus system (CAN) 23.
  • CAN vehicle bus system
  • Fig. 2 shows an embodiment of a steering system with an open center according to the invention.
  • the same parts of the steering have been provided here and below with the same reference numerals as in FIG. 1.
  • a valve unit 24 which has a hydraulic linear slide valve 25 and a safety valve 26.
  • the linear switching valve 25 is actuated by an electrical actuator 27, preferably via a servo motor and a gear.
  • a valve slide 28 is placed in different slide positions.
  • valve block 29, three switching positions are possible due to the linear movement of the linear slide valve 25: a first switching end position in which a pressure medium in the two hydraulic chambers 18, 19 can be introduced and / or can be led out of the two hydraulic chambers 18, 19 so that there is no pressure difference between the two chambers (middle position), a second switching end position in which the pressure medium flows into the first hydraulic chamber 18 can be introduced and can be led out of the second hydraulic chambers 19, and a third switching end position, in which the pressure medium can be led out of the first hydraulic chambers 18 and can be introduced into the second hydraulic chamber 19, so that a maximum pressure difference between the pressures formed in both hydraulic chambers is set, the pressure difference being continuously adjustable between these end positions.
  • two hydraulic pressure sensors 33, 34 are arranged, by means of which the hydraulic pressure in the two hydraulic chambers 18, 19 is detected.
  • a torque sensor 35 is also arranged, which detects the torque on a steering wheel shaft 5 of the vehicle steering system.
  • the torque sensor 35 essentially serves to generate a setpoint specification for the regulation of the differential pressure.
  • Steering assistance is provided by means of an electronic unit, the ECU 36, in accordance with the determined steering wheel angle 37, the torque 38 determined on the steering wheel shaft 5, the vehicle speed or a brake control system
  • Vehicle reference speed 39 and according to other influencing variables such as e.g. External control 40 by a driving stability control or by assistance systems for lane keeping or for parking processes.
  • a hydraulic slide valve is also provided as the safety valve 26, which can be switched into different switching positions by means of two hydraulic switching valves 41, 42 by a linear movement of a safety valve switching element 43 and in cooperation with bores 31, 32, 44, 45.
  • the safety valve 26 Through the safety valve 26 are the two hydraulic chambers 18, 19 can be directly connected to one another via the bores 44, 45 and connecting lines 46, 47. In this way, the function of the vehicle steering (without steering support) is ensured even if the support function or the actuator system of the steering support fails.
  • valve unit 24 with the switching valves 41, 42 and the actuator 27 is preferably combined in a hydraulic unit 48, whereby also the
  • Pressure sensors 33, 34 can be integrated therein (not shown here).
  • An electronic block 49 with the interfaces to the signals 37-40 and with the ECU 36 is preferably arranged on the hydraulic unit 48.
  • the electronics block 49 is supplied with voltage by the vehicle electrical system (supply voltage UBATT 50).
  • Fig. 3 shows a further embodiment of a steering system with an open center according to the invention.
  • the pressure control here does not take place in accordance with pressure sensor signals (51, 52 in FIG. 2), but a linear travel sensor 53 is provided on the actuator 27.
  • a linear travel sensor 53 is provided on the actuator 27.
  • the hydraulic pressures in the chambers 18, 19 are determined or estimated and used 54 to control the steering assistance.
  • FIG. 4 shows a further embodiment of a steering system with an open center according to the invention, which has a valve unit with four analogized valves 55, 56, 57, 58, which are controlled by the ECU 36 in order to regulate the pressure in the two hydraulic chambers 18, 19 become 59,60,61,62. Furthermore, a switching valve 63 is provided as a safety valve, by means of which the two hydraulic chambers can be connected directly to one another. The switching valve 63 is also controlled 64 by the ECU 36.
  • Fig. 5 shows an embodiment of a closed center steering according to the invention, which is similar to the embodiment shown in Fig. 4 and also has four analog valves 65-58.
  • a high-pressure accumulator 69 for the pressure medium is provided for the "closed center" version.
  • the high-pressure accumulator 69 advantageously always provides an energy supply for the steering assistance.
  • the accumulator 69 is only charged by means of the pump 13 when the pressure drops below a lower limit, here approximately 120 bar. Charging is advantageously carried out up to a maximum pressure of approx. 180 bar.
  • the pump 13 is therefore integrated into the drive via a clutch 70, here via a belt drive.
  • the coupling 70 can advantageously be formed with the pump 13 as a structural unit.
  • the control takes place via a further pressure sensor 71, which measures the pressure in a high-pressure accumulator and supplies 72 to the ECU 36.
  • the safety concept is shown in more detail by way of example in FIGS. 6 to 9.
  • FIG. 6 shows the valve unit according to the invention with a linear slide valve 25 and a safety valve 26 in the closed switching position in a schematic manner
  • FIG. 7 shows that shown in FIG. 8 Valve unit 24 in a cross section.
  • the hydraulic unit 48 with the valve unit 24 corresponds to the form shown in FIGS. 2 and 3 and described above.
  • the linear switching valve 25 is in the first
  • Switching end position (middle position), in which the pressure medium can be introduced into the two hydraulic chambers 18, 19 and / or can be led out of the two hydraulic chambers 18, 19.
  • this central position is automatically assumed by the valve slide when the actuator does not regulate a specific position. In the event of a fault, this always ensures that the steering is operated (without servo assistance).
  • the safety valve 26 is here in the illustration in the de-energized switching position. That means the two switching valves 41, 42 are de-energized here. As a result, the safety valve 26 is closed. This also represents an error case
  • connecting lines 44, 45 to the hydraulic chambers;) 18, 19 are connected to one another.
  • a system error in the steering boost function then leaves the basic steering function (without steering boost) of the vehicle steering unaffected.
  • FIGS. 8 and 9 correspond to the illustration in FIGS. 6 and 7, the safety valve 26 being shown here in the open switching position.
  • the switching valves 41, 42 are energized.
  • the linear slide valve 25 is in the first slide position (middle position). Since the safety valve 26 is now open, the hydraulic chambers 18, 19 are not directly connected to one another. A reinforcement function of the steering can be Adjust by moving the linear slide valve 25, whereby a (controllable) differential pressure between the individual chambers 18, 19 arises.
  • the vehicle steering system according to the invention can advantageously be used with conventional rack and pinion steering. Since - in contrast to conventional hydraulic steering systems in which the rotary slide steering valve is not coupled via the torsion bar - a mechanically decoupled steering valve or valves are provided here, the steering assistance can also be controlled externally.
  • an actuator electronic mechanical converter
  • an actuator is controlled in a translatory manner in accordance with a controller specification and effects a corresponding, desired valve actuation.

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

Abstract

L'invention concerne un système de direction pour automobiles, comprenant un levier de direction actionnable par le conducteur, ainsi qu'une unité d'ajustement associée au roues directrices du véhicule, qui est reliée, de manière interactive, au levier de direction et sert à faire pivoter les roues directrices du véhicule, par l'intermédiaire d'éventuellement d'autres éléments, pour ajuster un angle de braquage voulu. L'unité d'ajustement est un groupe hydraulique comportant deux chambres hydrauliques, séparées par un piston hydraulique et pouvant être sollicités par la pression d'une source de pression hydraulique. Le groupe hydraulique peut être relié par l'intermédiaire d'une unité de soupape, à la source de pression hydraulique ou à un réservoir de réserve en fluide hydraulique et une assistance hydraulique de direction peut être ajustée à l'aide de l'unité de soupape.
EP05716646A 2004-02-10 2005-02-08 Systeme de direction de vehicule Withdrawn EP1713678A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102004006581 2004-02-10
PCT/EP2005/050535 WO2005077731A1 (fr) 2004-02-10 2005-02-08 Systeme de direction de vehicule

Publications (1)

Publication Number Publication Date
EP1713678A1 true EP1713678A1 (fr) 2006-10-25

Family

ID=34853418

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05716646A Withdrawn EP1713678A1 (fr) 2004-02-10 2005-02-08 Systeme de direction de vehicule

Country Status (4)

Country Link
US (1) US20070169471A1 (fr)
EP (1) EP1713678A1 (fr)
JP (1) JP2007522020A (fr)
WO (1) WO2005077731A1 (fr)

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DE102004048689B3 (de) * 2004-10-06 2005-10-20 Siemens Ag Zweistufiges Servoventil
DE102005056167A1 (de) * 2004-12-27 2006-07-13 Continental Teves Ag & Co. Ohg Fahrzeuglenkung und Verfahren zur Regelung einer Fahrzeuglenkung
JP5010230B2 (ja) * 2006-10-16 2012-08-29 トヨタ自動車株式会社 パワーステアリング装置
US7849686B2 (en) 2007-02-07 2010-12-14 Sauer-Danfoss Aps Valve assembly and a hydraulic actuator comprising the valve assembly
US7690196B2 (en) 2007-02-07 2010-04-06 Sauer-Danfoss Aps Hydraulic actuator having an auxiliary valve
US7624671B2 (en) 2007-02-07 2009-12-01 Sauer-Danfoss Aps Hydraulic actuator for a servomotor with an end lock function
US7677035B2 (en) 2007-02-07 2010-03-16 Sauer-Danfoss Aps Control system for a hydraulic servomotor
EP2199186B1 (fr) * 2008-12-17 2015-06-03 HAWE Hydraulik SE Dispositif de commande de direction hydraulique
DE102009017879A1 (de) * 2009-04-17 2010-10-21 Festo Ag & Co. Kg Fluidtechnisches System
DK3020983T3 (da) 2014-11-14 2020-08-10 Danfoss Power Solutions Aps Indgangsmodul til en ventilgruppe
IT201900010539A1 (it) * 2019-07-01 2021-01-01 Ognibene Power Spa Gruppo di sterzatura idrostatico

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JPS63232074A (ja) * 1987-03-20 1988-09-28 Toyota Central Res & Dev Lab Inc 車両用操舵装置
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JP2953537B2 (ja) * 1991-02-05 1999-09-27 自動車機器株式会社 動力舵取装置の操舵力制御装置
DE4242441C1 (de) * 1992-12-16 1994-05-19 Daimler Benz Ag Servosteuerung, insbesondere Servolenkung für Kraftfahrzeuge
DE4330338C1 (de) * 1993-09-08 1994-09-08 Daimler Benz Ag Fluidische, insbesondere hydraulische Servosteuerung
JP3687252B2 (ja) * 1997-02-28 2005-08-24 日産自動車株式会社 自動車の操舵装置
DE19819404C2 (de) * 1998-04-30 2000-03-02 Daimler Chrysler Ag Lenkvorrichtung
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Also Published As

Publication number Publication date
WO2005077731A1 (fr) 2005-08-25
JP2007522020A (ja) 2007-08-09
US20070169471A1 (en) 2007-07-26

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