[go: up one dir, main page]
More Web Proxy on the site http://driver.im/

WO2009074216A1 - Système de direction assistée électro-hydraulique et accumulateur de pression hydraulique pour système de direction assistée - Google Patents

Système de direction assistée électro-hydraulique et accumulateur de pression hydraulique pour système de direction assistée Download PDF

Info

Publication number
WO2009074216A1
WO2009074216A1 PCT/EP2008/009823 EP2008009823W WO2009074216A1 WO 2009074216 A1 WO2009074216 A1 WO 2009074216A1 EP 2008009823 W EP2008009823 W EP 2008009823W WO 2009074216 A1 WO2009074216 A1 WO 2009074216A1
Authority
WO
WIPO (PCT)
Prior art keywords
pressure
chamber
steering system
valve
piston
Prior art date
Application number
PCT/EP2008/009823
Other languages
German (de)
English (en)
Inventor
Heinz-Dieter Heitzer
Peter Zeiler
Original Assignee
Trw Automative 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 Trw Automative Gmbh filed Critical Trw Automative Gmbh
Publication of WO2009074216A1 publication Critical patent/WO2009074216A1/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
    • B62D5/065—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 specially adapted means for varying pressurised fluid supply based on need, e.g. on-demand, variable assist
    • 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
    • B62D5/062—Details, component parts

Definitions

  • the invention relates to an electrohydraulic power steering system and a hydraulic pressure accumulator for a power steering system, with a pressure accumulator housing in which a pressure chamber and a biasing chamber are formed, a piston acted upon in the direction of the pressure chamber, which is movable between a first end position and in a second end position and two chambers separated from each other, wherein in the piston, a check valve is integrated, which connects the pressure chamber and the biasing chamber in an open position, and wherein the pressure chamber has a pressure chamber port through which the pressure accumulator is connected to a hydraulic circuit of the power steering system.
  • a steering system As an electrohydraulic power steering system, a steering system is referred to below in which the power assistance generated by an electric motor is transmitted to a rack of the steering system by means of a hydrostatic circuit.
  • the electric motor thereby drives a reversibly operating pump, wherein the pump has two connections which are each connected via hose lines with one of two working chambers of a steering cylinder.
  • the pressure difference on the steering cylinder is thus determined by the drive torque of the pump or the output torque of the electric motor, wherein the working chambers are usually associated with pressure sensors that monitor the hydraulic pressure in the steering cylinder.
  • Such an electro-hydraulic power steering system is already known from US 6,152,254 A.
  • a steering torque sensor detects the applied by a driver on the steering wheel steering torque, from which a target value for the pressure difference is calculated on the steering cylinder.
  • the pressure difference detected by the pressure sensors in the working chambers is then adjusted to the current desired value. It has been found that a stiff and play-free coupling between the electric motor and the rack is necessary for proper operation of this loop. Therefore, the occurrence of cavitation phenomena in the hydrostatic circuit must be prevented as possible, and the possibly left in the filling or leakage air bubbles in the steering system should be able to escape automatically over time.
  • the object of the invention is therefore to provide a prestressed power steering system, which provides a largely constant biasing pressure in normal operation, can be filled with little effort and biased and allows an advantageous, automatic venting.
  • an electrohydraulic power steering system comprising a hydraulic circuit comprising a pump, a cylinder / piston unit and a hydraulic pressure accumulator, the pump being designed as a reversible pump and optionally a first working chamber or a second working chamber of the cylinders.
  • Piston unit can act on a hydraulic pressure, and wherein at a suction port of the pump is applied via the pressure accumulator adjustable biasing pressure. Due to this preload pressure at the suction connection of the pump cavitation phenomena in the power steering system are largely prevented.
  • each working chamber is associated with a pressure sensor, wherein the smaller of the two sensed pressure values is defined as a biasing pressure.
  • a biasing pump is provided which is in communication with a reservoir under atmospheric pressure and a pressure chamber of the pressure accumulator, wherein is activated pump at a drop in the biasing pressure below a predetermined value and promotes hydraulic fluid from the reservoir into the pressure chamber.
  • the biasing pump compensates for pressure fluctuations in the accumulator, which arise for example due to temperature changes, leaks in the hydraulic circuit and / or other changes in volume.
  • a vibrating armature pump is particularly suitable and is therefore preferably used as a biasing pump. Since the pressure fluctuations are rather low when using a suitable pressure accumulator, an inexpensive and compact miniature version of the oscillating armature pump with a low delivery volume and a delivery pressure of a few bar is usually sufficient to compensate for these pressure fluctuations.
  • the hydraulic circuit has an electromagnetically actuated directional control valve and an electromagnetically actuated safety valve, wherein the hydraulic system can be filled and / or prestressed in an actuating position of the valves by means of the pump.
  • the hydraulic circuit has an electronically actuated directional control valve and an electromagnetically actuated safety valve, wherein the hydraulic system can be filled and / or prestressed in an actuating position of the directional control valve and an unconfirmed basic position of the safety valve by means of the pump.
  • the hydraulic circuit has a high-flow valve, which connects the working chambers of the cylinder / piston unit with each other and with the pressure accumulator in its unactuated basic position, wherein the hydraulic circuit can be filled and / or prestressed in this unactuated basic position of the high-flow valve by means of the pump , and wherein the high-flow valve is preferably pilot-operated.
  • This design of the hydraulic circuit allows an advantageous realization of the filling or preload function and the fail-safe function with only a single high-flow valve.
  • only two small, standardized low-flow valves are needed for active pilot control of the high-flow valve that results in a compact power steering system that can be produced inexpensively and can be operated particularly energy-saving as a result of the pilot control.
  • the high-flow valve is preferably a 6/2-way valve or a 5/2-way valve.
  • the high-flow valve is precontrolled by two solenoid-operated, designed as 2/2-way valves pilot valves, wherein an unconfirmed basic position of a pilot valve is an open position and an unconfirmed basic position of the other pilot valve is a blocking position.
  • pilot valves are designed for low hydraulic fluid flow and require only small actuation magnets with low energy consumption for a valve circuit.
  • Another object of the invention is to provide a pressure accumulator for a power steering system which ensures a substantially constant bias of the hydraulic circuit and enables easy filling or preloading of the power steering system.
  • the object is achieved by a hydraulic accumulator of the type mentioned above, wherein in the pressure chamber of the pressure accumulator a collection space is formed for gas bubbles and wherein the piston occupies the first end position from a pre-definable hydraulic pressure in the pressure chamber, in which the pressure chamber via the collection space the preload chamber is in communication.
  • the biasing chamber may be partially filled with hydraulic fluid, which is substantially below atmospheric pressure.
  • the biasing chamber is used as a compensating volume, which receives as required hydraulic fluid from the pressure chamber or discharges into the pressure chamber to keep the pressure in the hydraulic circuit as constant as possible.
  • the collection space in the second end position of the piston is separated from the pressure chamber port and the check valve can assume its open position. This ensures that the hydraulic circuit via the pressure chamber connection no gas bubbles from the collection chamber, but only sucks hydraulic fluid from the biasing chamber.
  • a collection space bridging element may be provided in the pressure chamber substantially sealingly connecting the biasing chamber and the pressure chamber port in the second end position of the piston when the check valve is open.
  • the biasing chamber is in the first end position of the piston via axial notches in a peripheral wall of the pressure accumulator housing with the
  • a piston stop with an axial pin can be provided in the preload chamber, the pin in the first end position of the piston holding the check valve in the open position, so that the preload chamber communicates with the collection space of the pressure chamber.
  • a release of excess hydraulic fluid from the hydraulic circuit via the check valve is possible, which is forced by the pin in its open position and establishes a connection to the biasing chamber.
  • the formation of axial notches in the peripheral wall of the pressure accumulator housing is therefore no longer necessary.
  • FIG. 1 shows the schematic circuit diagram of a power steering system according to the invention with a hydraulic circuit according to a first embodiment
  • - Figure 2 is a longitudinal section through a first embodiment of the pressure accumulator according to the invention
  • - Figure 3 is a longitudinal section through a second embodiment of the pressure accumulator according to the invention
  • FIG. 4 shows a perspective sectional view of an accumulator piston for the pressure accumulator according to the invention, according to a third embodiment;
  • - Figures 5a and 5b each show a detail section through a check valve of the pressure accumulator according to the invention;
  • FIG. 6 shows a (secondary) hydraulic circuit for filling or pretensioning the power steering system according to the invention
  • FIG. 7 shows the schematic circuit diagram of a power steering system according to the invention with a hydraulic circuit according to a second embodiment
  • FIG. 8 is a schematic circuit diagram of a power steering system according to the invention with a hydraulic circuit according to a third embodiment
  • FIG. 9 shows the schematic circuit diagram of a power steering system according to the invention with a hydraulic circuit according to a fourth embodiment; and FIG. 10 shows a schematic detail section through a high-flow valve of the
  • Hydraulic circuit according to Figure 9 in an unactuated initial position and an actuating position.
  • Figure 1 is a hydraulic circuit diagram for a power steering system 8 of a
  • the circuit diagram shows concretely a preloaded hydraulic circuit 10 for an electrohydraulic power steering system 8.
  • the electro-hydraulic power steering system 8 comprises a steering shaft 11, which is coupled in a known manner via a steering gear 12 with a rack 14, which in turn cooperates with steerable wheels of the motor vehicle (not shown).
  • a steering torque and / or steering angle sensor 16 is provided, which passes on its sensor data to an electronic control unit 18 of a motor-pump unit 20.
  • the motor-pump unit 20 is the interface between the electrical and the hydraulic part of the electro-hydraulic power steering system 8 and, in addition to the electronic control unit 18, also has a motor 22 and a reversible pump 24.
  • the power steering system 8 further comprises a cylinder / piston unit 27 with two working chambers 28, 30, which are pressurized depending on the conveying direction of the pump 24 and correspondingly cause or support an axial movement of the rack 14 in a first or an opposite second direction ,
  • the prevailing in the working chambers 28, 30 pressure is detected by pressure sensors 31 and transmitted to the electronic control unit 18.
  • the control unit 18 is additionally connected to a power supply 33 and further data acquisition units 35.
  • the power steering system 8 according to FIG. 1 also has a safety valve 32, which shorts the working chambers 28, 30 of the cylinder / piston unit 27 in a first valve position according to FIG. 1, so that in the event of a system failure no hydraulic blockage occurs.
  • the motor vehicle steering then works purely mechanically in this case.
  • the safety valve 32 is designed as an electromagnetically actuated directional control valve, wherein a spring element 34 ensures that the safety valve 32 in the non-energized state to its normal position, i. moved into the illustrated, open valve position and takes over the function of a well-known "fail-safe" valve.
  • a special feature of the power steering system 8 is the design of a pressure accumulator 36, which is shown schematically in Figure 1 and shown separately and in detail in Figure 2 according to a first embodiment.
  • the pressure accumulator 36 comprises a pressure accumulator housing 38, in which a pressure chamber 40 and a biasing chamber 42 are formed, and a movable piston 44 which is acted upon in the direction of the pressure chamber 40 and the two chambers 40, 42 separated from each other.
  • a check valve 46 integrated, which connects the pressure chamber 40 and the biasing chamber 42 in its open position.
  • the pressure chamber 40 has a pressure chamber connection 48, via which the pressure accumulator 36 can be connected to the hydraulic circuit 10 of the power steering system 8 (see FIG. 1).
  • a collection space 50 is formed for gas bubbles through which the pressure chamber 40 is in the first end position of the piston 44 with the biasing chamber 42 in communication, the piston 44 assumes the first end position from a predetermined hydraulic pressure in the pressure chamber 40.
  • the collection space 50 is an annular space which is formed around a collection space bridging element 58 and is bounded on the outside by a peripheral wall 52 of the pressure storage housing 38.
  • axially aligned notches 54 are provided, which connect the biasing chamber 42 in the first end position of the piston 44 with the collection space 50 of the pressure chamber 40.
  • the first end position is identical to an upper stop position of the piston 44.
  • a compression spring 55 is provided, which acts on the piston 44 in the direction of the pressure chamber 40. Furthermore, the biasing chamber 42 is at least partially filled with hydraulic fluid which is substantially at atmospheric pressure. According to Figure 2, a tank 56 is provided with a vent cover 57 to increase the Vorspannschvolumens still, the vent cover 57 may be placed directly on the pressure accumulator housing 38 in other embodiments. If the piston 44 is moved counter to the force of the compression spring 55 by a growing pressure in the hydraulic circuit 10 in its first end position, so gas and / or hydraulic fluid from the pressure chamber 40 via the notches 54 in the biasing chamber 42 to flow.
  • the collection space 50 Since the collection space 50 first reaches the axial notches 54, initially predominantly gas fractions flow from the pressure chamber 40 into the biasing chamber 42, whereby the hydraulic circuit 10 is vented in the desired manner.
  • the gas bubbles which accumulate in the collection space 50 remain, for example, when filling the power steering system 8 in the hydraulic circuit 10 or cavitation or leakage in the power steering system 8 penetrated.
  • a Bottom of the piston 44 is slightly conical (not shown), so that the gas bubbles collect primarily on the peripheral wall 52 of the pressure accumulator housing 38 and discharged via the notches 54 in the biasing chamber 42.
  • the collection space 50 In the second end position, ie the lower stop position of the piston 44, the collection space 50 is separated from the pressure chamber connection 48.
  • the collection space bridging element 58 is provided in the pressure chamber 40 (see Figure 2), which substantially closes the preload chamber 42 and the pressure chamber port 48 in the second end position of the piston 44 (with the check valve 46 open) combines.
  • the hydraulic circuit 10 sucks in hydraulic fluid in the second end position of the piston 44, it is thus ensured that no air from the collection chamber 50, but only hydraulic fluid from the preload chamber 42 is sucked in via the pressure chamber connection 48.
  • the prestressing pressure defined by the pressure accumulator 36 is largely constant. This preload pressure is adjusted significantly by the compression spring 55. A hydrostatic component from the pressureless hydraulic fluid in the biasing chamber 42 is usually negligible.
  • Another advantage of the pressure accumulator 36 is the automatic venting of the hydraulic circuit 10 at overpressure, ie at a hydraulic pressure in the pressure chamber 40, which is above a maximum desired biasing pressure.
  • 3 shows a second embodiment of the pressure accumulator 36, which differs from the first embodiment described above, but only by a changed overpressure ventilation.
  • a piston stopper 60 is provided with an axial pin 62 in the biasing chamber 42 according to Figure 3, wherein the pin 62 in the first end position of the piston 44, the check valve 46 is kept open, so that the Biasing chamber 42 is in communication with the pressure chamber 40.
  • a channel 64 is provided in the piston 44, the biasing chamber 42 with open check valve 46 with the collection space 50 connects, so that in this second embodiment of the accumulator 36, a venting of the hydraulic circuit 10 in the first end position of the piston 44 is possible.
  • the check valve 46 assumes its open position both in the first end position and in the second end position of the piston 44 and allows a fluid flow between the pressure chamber 40 and the biasing chamber 42nd
  • FIG. 4 shows the piston 44 for a third embodiment of the pressure accumulator 36. Except for the piston 44, this third embodiment corresponds to the previously described, second embodiment of the pressure accumulator 36 according to FIG. 3.
  • the modified piston 44 has at its lower end face instead of the collection space.
  • Bridging element 58 (see Figures 2 and 3) has a funnel-shaped recess 65, which tapers toward the check valve 46. Any existing gas bubbles collect in this funnel-shaped recess 65 and flow at an opening of the check valve 46 through the pin 62 in the first end position of the piston 44 in the biasing chamber 42.
  • a desired automatic venting of the hydraulic circuit 10 is given at overpressure .
  • FIGS. 5a and 5b show a particularly preferred embodiment of the check valve 46, which is integrated into the piston 44 of the accumulator 36, preferably screwed.
  • the check valve 46 has a valve member 68, which is made of a hardened, polished steel ball.
  • the valve member 68 In a blocking position of the valve 46 according to FIG. 5 a, the valve member 68 with its spherical surface section seals against a valve seat 70.
  • the valve member 68 is radially almost free of play but guided along a valve axis A movable in a piston bore 72.
  • Recesses 74 in the valve member 68 ensure, in an open position of the check valve 46 (see FIG. 5b), a low-turbulence flow with a low pressure loss.
  • the Asked valve construction is particularly advantageous because there are no valve parts in a flow space 73 downstream of the valve member 68, which could hinder fluid flow.
  • the guide and the exact position of the valve member 68 are achieved by means of a guide sleeve 76, which adjoins the approximately hemispherical portion of the valve member 68.
  • a closing spring 78 of the check valve 46 is arranged in the radial direction between the guide sleeve 76 and a peripheral wall of the piston bore 72 and acts on the valve member 68 in the blocking position according to FIG. 5a.
  • An axial spring abutment serves as a valve sleeve 80, which is screwed into the piston bore 72 in the piston 44 for fastening the check valve 46.
  • the secondary hydraulic circuit 82 has for this purpose a biasing pump 84 with a motor 86, wherein the biasing pump 84 is preferably a miniaturized oscillating armature pump.
  • a suction side of the biasing pump 84 is connected via an unpressurized reservoir to the biasing chamber 42 and a pressure side of the biasing pump 84 to the pressure chamber 40 of the pressure accumulator 36.
  • the non-pressurized reservoir is preferably the biasing chamber 42 or, as shown in Figure 6, the tank 56.
  • a check valve 88 is provided which prevents hydraulic fluid flow from the pressure chamber 40 to the biasing chamber 42 with unconfirmed biasing pump 84 ,
  • the motor 86 of the secondary hydraulic circuit 82 is also connected to the power supply 33 and is actuated by the electronic control unit 18 via a switch 90.
  • the electronic control unit 18 checks on the basis of the pressure sensors 31, whether in each of the working chambers 28, 30 at least the predetermined, minimum bias pressure prevails. If this is not the case, the switch 90 is closed, and the biasing pump 84 delivers hydraulic fluid from the biasing chamber 42 into the pressure chamber 40 until at least the minimum bias pressure in each of the working chambers 28, 30 is established.
  • the biasing pump 84 may also deliver up to a maximum biasing pressure at which the piston 44 is in its second end position and beneficial venting of the primary hydraulic circuit 10 occurs.
  • activation of the biasing pump 84 to adjust the biasing pressure occurs as part of a startup routine when starting the vehicle.
  • the switch 90 then remains open and is not activated by the electronic control unit 18. This rare but regular check and readjustment of the biasing pressure by the biasing pump 84 is sufficient to compensate for leakage in the primary hydraulic circuit 10 and to maintain the biasing pressure substantially constant.
  • FIG. 7 shows the electrohydraulic power steering system 8 with a
  • the electronic control unit 18 activates the valves 32, 92, so that they assume their Betuschistssteliung according to Figure 7. Thereafter, the pump 24 is operated so that it sucks hydraulic fluid from the preload chamber 42 of the pressure accumulator 36 via the connecting line 94 and delivers it to the first working chamber 28 of the cylinder / piston unit 27.
  • the piston 95 moves due to this pressurization of the first working chamber 28 in its upper stop position ( Figure 7), in the through the overflow 96 a Overflow of gas and / or hydraulic fluid from the first working chamber 28 into the second working chamber 30 is possible. From the upper working chamber 30, the gas and / or hydraulic fluid is introduced via the directional control valve 92 into the pressure chamber 40 of the pressure accumulator 36.
  • the pressure accumulator 36 is designed in such a way that, in the first place, venting, ie an overflow of gas, takes place during the overpressure relief, before an overflow of hydraulic fluid takes place.
  • the safety valve 32 is operated as a conventional "fail-safe" valve and the spring-loaded directional control valve 92 is deactivated so that it is in its normal position (lower valve position in FIG).
  • the electro-hydraulic power steering system 8 is thereby converted back into its conventional operating function and can provide a desired power assistance in the following.
  • a check valve 98 is particularly preferably provided, which prevents in normal operation at a pressurization of the second working chamber 30, a flow of hydraulic fluid into the biasing chamber 42 of the accumulator 36.
  • Section A in FIG. 7 shows an alternative embodiment of the directional control valve 92, in which a leakage connection 99 of the pump 24 is not blocked in the actuation position of the valve 92 but is connected to the pump connection 26.
  • a plurality of components of the power steering system 8 to compact, pre-assembled components such as the motor-pump unit 20 or a valve block 100 summarized, which is shown in Figure 7 by dashed rectangles.
  • the described process for biasing the hydraulic circuit 10 in this second embodiment may also be in a startup routine at start up be integrated with the vehicle, so that the formation of a secondary hydraulic circuit 82 according to Figure 6 is unnecessary.
  • FIG. 8 shows the electrohydraulic power steering system 8 with the (primary) hydraulic circuit 10 according to a third embodiment, in which no overflow grooves 96 are provided in the cylinder / piston unit 27 in contrast to the second embodiment according to FIG. 7, so that no overflow of Gas and / or hydraulic fluid from the first working chamber 28 into the second working chamber 30 is possible.
  • the hydraulic circuit 10 can be vented and biased in an operating position of the directional control valve 92 and an unactuated basic position of the safety valve 32 (see FIG.
  • the biasing of the power steering system 8 is exactly as described for Figure 7, except that the connection between the biasing chamber 42 and the pressure chamber 40 is not made by the overflow grooves 96 of the cylinder / piston unit 27, but by the safety valve 32.
  • a filling of the electro-hydraulic power steering system 8 is also possible in this third embodiment, but the piston 95 must be moved during the filling process by manually steering from one stop position to the other stop position to the present in the working chambers 28, 30 gas from the cylinder / piston Unit 27 to press.
  • the pressure accumulator 36 is designed so that it is not necessary to resort to output signals of the pressure sensors 31 for biasing the (primary) hydraulic circuit 10 since these output signals may have a zero point shift (so-called drift) after a longer service life of the vehicle can.
  • the hydraulic circuit 10 is preferably biased, for example, every time the vehicle is started until the piston 44 of the pressure accumulator 36 reaches the axial notches 54, or until the axial pin 62 presses the check valve 46 in the piston 44 of the pressure accumulator 36. In this first end position of the piston 44, the biasing pressure in the hydraulic circuit 10 is clearly determined by the compression spring 55 of the pressure accumulator 36 and can be used to balance the two pressure sensors 31.
  • FIG. 9 shows the electrohydraulic power steering system 8 with the (primary) hydraulic circuit 10 according to a fourth embodiment.
  • This fourth embodiment is very similar to the second and third embodiments of the electrohydraulic power steering system 8, for which reason reference is also made to the above description of FIGS. 7 and 8.
  • the essential difference is that the safety valve 32 and the directional control valve 92 are combined to form a single high-flow valve 102, wherein two low-flow valves in the form of pilot valves 104, 106 are provided for the pilot control of the high-flow valve 102.
  • a valve designed for a large hydraulic fluid flow (eg for moving the rack 14) is referred to as a high-flow valve, whereas a valve designed for a low hydraulic fluid flow (eg for valve precontrol) is referred to as a low-flow valve.
  • the safety valve 32 and the directional control valve 92 may be formed in FIGS. 7 and 8 as pilot-controlled high-flow valves in order to reduce the size of the control magnets and thus also the energy requirement for active valve control.
  • the high-flow valve 102 is directly controlled.
  • the high-flow valve 102 is shown as a 6/2-way valve with the valve connections a to f and the pressure connections g and h.
  • the valve connections a and b can also be combined to form a valve connection a ', which in the unactuated basic position is in communication with the valve connections d and e and in the actuation position with the valve connection f.
  • the high flow valve 102 is then a 5/2-way valve.
  • the high-flow valve 102 is acted upon by a spring element 108 in an unconfirmed basic position; according to FIG.
  • the hydraulic circuit 10 in this unactuated basic position of the high-flow valve 102 by means of the reversible pump 24 can be filled and / or prestressed.
  • This design of the hydraulic circuit 10 allows an advantageous realization of the filling or preload function and the fail-safe function with only a single high-flow valve 102.
  • pilot valves 104, 106 are in the present case electromagnetically actuated 2/2-way valves, as used, for example, in chassis stabilization systems or vehicle brake systems.
  • the pressure connections g and h of the high-flow valve 102 are each connected to the preload chamber 42 of the pressure accumulator 36, so that the high-flow valve 102 is in its unactuated basic position due to the spring action (FIG. 9).
  • the power steering system 8 according to this fourth embodiment variant is overall very compact, particularly inexpensive to produce and can be operated extremely energy-saving due to the pilot control.
  • the pilot valves 104, 106 When activated by the respective drive magnets, the pilot valves 104, 106 are switched so that the pressure port h of the high-flow valve 102 remains connected to the biasing chamber 42, but the pressure port g is in communication with the pressure chamber 40. The resulting from the pressure difference between the pressure ports g and h is so great that it overcomes the force of the spring element 108 and the high-flow valve 102 switches to its (left) operating position. In this operating position, the valve ports a and f and c and e are connected to each other while the valve ports b and d are locked. On the direction of rotation and speed of the reversible pump 24 can thus be generated in the operating position, a desired rack power in the power steering system 8.
  • FIG. 10 shows the high-flow valve 102 according to FIG. 9 with the valve connections a to f and the pressure connections g and h in a schematic detail section.
  • the unactuated valve base position to see, and below the operating position in which a movable valve body 110 of the high-flow valve 102 relative to the valve base position in the direction of the arrow 112 is moved to the left.

Landscapes

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

Abstract

Un système de direction assistée électro-hydraulique (8) présente un circuit hydraulique (10) qui comprend une pompe (24), une unité cylindre/piston (27) et un accumulateur de pression hydraulique (36), et est caractérisé en ce que la pompe (24) est configurée en tant que pompe réversible, et peut appliquer une pression hydraulique, facultativement, dans une première chambre de travail (28) ou dans une seconde chambre de travail (30) de l'unité cylindre/piston (27), et en ce qu'une pression de précontrainte réglable via l'accumulateur de pression (36) est appliquée sur un raccordement d'aspiration (25, 26) de la pompe (24). Un accumulateur de pression hydraulique (36) pour un système de direction assistée, de préférence pour le système de direction assistée électro-hydraulique précité (8), comprend un boîtier (38) d'accumulateur de pression, dans lequel sont agencées une chambre de pression (40) et une chambre de précontrainte (42), ainsi qu'un piston (44) sollicité en direction de la chambre de pression (40), déplaçable entre une première position de fin de course et une seconde position de fin de course, et séparant les deux chambres (40, 42) entre elles, cependant qu'une soupape antiretour (46) est intégrée dans le piston (44), ladite soupape reliant entre elles, en position d'ouverture, la chambre de pression (40) et la chambre de précontrainte (42). La chambre de pression (40) présente une connexion de chambre de pression (48) qui peut être raccordée, via l'accumulateur de pression (36), au circuit hydraulique du système de direction assistée (8); un espace collecteur (50) pour les bulles de gaz étant formé dans la chambre de pression (40); et le piston (44) prenant, à partir d'une pression hydraulique prédéterminable dans la chambre de pression (40), la première position de fin de course, dans laquelle la chambre de pression (40) est en communication, via l'espace collecteur (50), avec la chambre de précontrainte (42).
PCT/EP2008/009823 2007-12-10 2008-11-20 Système de direction assistée électro-hydraulique et accumulateur de pression hydraulique pour système de direction assistée WO2009074216A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE200710059440 DE102007059440A1 (de) 2007-12-10 2007-12-10 Elektrohydraulisches Servolenksystem sowie hydraulischer Druckspeicher für ein Servolenksystem
DE102007059440.4 2007-12-10

Publications (1)

Publication Number Publication Date
WO2009074216A1 true WO2009074216A1 (fr) 2009-06-18

Family

ID=40419000

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2008/009823 WO2009074216A1 (fr) 2007-12-10 2008-11-20 Système de direction assistée électro-hydraulique et accumulateur de pression hydraulique pour système de direction assistée

Country Status (2)

Country Link
DE (1) DE102007059440A1 (fr)
WO (1) WO2009074216A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022179652A1 (fr) * 2021-02-23 2022-09-01 Schaeffler Technologies AG & Co. KG Dispositif hydraulique

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102021103817A1 (de) 2021-02-18 2022-08-18 Knorr-Bremse Systeme für Nutzfahrzeuge GmbH Ventileinrichtung für eine Lenkvorrichtung eines Fahrzeugs, Lenkvorrichtung und Verfahren und Steuergerät zum Ansteuern einer Ventileinrichtung
DE102021103818A1 (de) 2021-02-18 2022-08-18 Knorr-Bremse Systeme für Nutzfahrzeuge GmbH Steuergerät für ein Fahrzeug mit einer Lenkvorrichtung, Lenkvorrichtung und Verfahren zum Kühlen eines Elektromotors für eine Lenkvorrichtung

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1425592A1 (de) * 1962-03-02 1968-12-05 Krupp Gmbh Selbsttaetiges Entlueftungsventil fuer Fluessigkeitsraeume
WO1999067119A1 (fr) * 1998-06-25 1999-12-29 Robert Bosch Gmbh Systeme de direction avec etage de reactivation hydraulique
US20050103560A1 (en) * 2003-01-09 2005-05-19 Hitachi Unisia Automotive, Ltd. Power steering system

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6152254A (en) 1998-06-23 2000-11-28 Techco Corporation Feedback and servo control for electric power steering system with hydraulic transmission

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1425592A1 (de) * 1962-03-02 1968-12-05 Krupp Gmbh Selbsttaetiges Entlueftungsventil fuer Fluessigkeitsraeume
WO1999067119A1 (fr) * 1998-06-25 1999-12-29 Robert Bosch Gmbh Systeme de direction avec etage de reactivation hydraulique
US20050103560A1 (en) * 2003-01-09 2005-05-19 Hitachi Unisia Automotive, Ltd. Power steering system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022179652A1 (fr) * 2021-02-23 2022-09-01 Schaeffler Technologies AG & Co. KG Dispositif hydraulique

Also Published As

Publication number Publication date
DE102007059440A1 (de) 2009-06-18

Similar Documents

Publication Publication Date Title
EP3233544B1 (fr) Châssis de véhicule automobile
EP2047133B1 (fr) Système d'accouplement
EP2488764B1 (fr) Système de vanne
DE102007056684B4 (de) Druckspeicher
EP0908653A1 (fr) Soupape pilote de limitation de pression
DE102004043897A1 (de) Antriebssystem mit gemeinsamen Steuerdruckanschluss
WO2010000423A1 (fr) Dispositif de vanne hydraulique
WO2015082321A1 (fr) Système hydraulique
EP2728203B1 (fr) Circuit de contrôle hydrostatique et son utilisation
DE102008027988A1 (de) Ausfallsicheres Ventil für aktive Rollsteuerung
DE102006046854B4 (de) Hydrostatische Verstelleinheit mit einem Servosystem und einer das Servosystem steuernden Ventileinheit
DE102006004423A1 (de) Ventilanordnung zur Ansteuerung eines Hubwerkes oder Anbaugerätes
WO2009074216A1 (fr) Système de direction assistée électro-hydraulique et accumulateur de pression hydraulique pour système de direction assistée
DE102009005768A1 (de) Druckregelung einer hydraulischen Antriebseinheit
DE4221088C2 (de) Aufhängungssystem für Fahrzeuge
DE102012214408A1 (de) Verstelleinrichtung für eine hydrostatische Maschine und hydrostatische Maschine
DE102004027971B4 (de) Hydraulische Lenkeinrichtung
WO2023036701A1 (fr) Dispositif d'actionnement pour au moins une charge entraînée par fluide
EP3464908A1 (fr) Système de vannes
EP3348430B1 (fr) Système d'amortissement hydraulique et véhicule articulé pourvu d'un tel système d'amortissement
WO2011003210A1 (fr) Système pour préparer une section transversale d'étranglement variable pour un flux de fluide
AT409112B (de) Hydraulische anordnung zur betätigung von beweglichen teilen an fahrzeugen, und vorspannventil für diese anordnung
WO2009150062A2 (fr) Système d'alimentation hydraulique conçu pour alimenter un consommateur hydraulique comprenant au moins une zone consommatrice
DE102021121843B3 (de) Hydropneumatisches Federungssystem
DE102004056661A1 (de) Elektronisch regelbare Fahrzeugbremsanlage

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 08859511

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 08859511

Country of ref document: EP

Kind code of ref document: A1