EP0609233A1 - Hydraulic control device. - Google Patents

Hydraulic control device.

Info

Publication number
EP0609233A1
EP0609233A1 EP92918895A EP92918895A EP0609233A1 EP 0609233 A1 EP0609233 A1 EP 0609233A1 EP 92918895 A EP92918895 A EP 92918895A EP 92918895 A EP92918895 A EP 92918895A EP 0609233 A1 EP0609233 A1 EP 0609233A1
Authority
EP
European Patent Office
Prior art keywords
pressure
valve
line
actuating device
hydraulic actuating
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.)
Granted
Application number
EP92918895A
Other languages
German (de)
French (fr)
Other versions
EP0609233B1 (en
Inventor
Helmut Rembold
Martin Mueller
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch 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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0609233A1 publication Critical patent/EP0609233A1/en
Application granted granted Critical
Publication of EP0609233B1 publication Critical patent/EP0609233B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
    • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
    • 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
    • F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
    • 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
    • F15B2211/2053—Type of pump
    • F15B2211/20538—Type of pump constant capacity
    • 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
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • 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
    • F15B2211/30505—Non-return valves, i.e. check 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
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F15B2211/3051—Cross-check 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
    • F15B2211/305—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
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/31505—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and a return line
    • F15B2211/31511—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and a return line having a single pressure source
    • 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
    • F15B2211/31523—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and an output member
    • F15B2211/31529—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and an output member 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
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/31552—Directional control characterised by the connections of the valve or valves in the circuit being connected to an output member and a return line
    • F15B2211/31558—Directional control characterised by the connections of the valve or valves in the circuit being connected to an output member and a return line having 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
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/88—Control measures for saving energy

Definitions

  • the invention is based on a hydraulic actuator according to the preamble of the main claim.
  • a hydraulic actuating device with a differential cylinder is known, the pressure chamber of which is assigned to the larger effective pressure surface of the differential piston and is controlled via a 3/2-way valve. By correspondingly clocking the 3/2-way valve, a pressure difference can be generated in the two pressure spaces, which causes an adjustment movement.
  • Such a hydraulic actuating device has the disadvantage that with stationary, ie. H. Non-moving differential pistons in the pressure chambers are subject to relatively high pressures, which are not or only slightly less than the adjustment pressures. As a result, in the holding position (stationary position) of the differential piston, a high expenditure of energy is necessary, which can lead to high costs in the operation of the hydraulic actuating device.
  • a hydraulic actuating device is known from DE-OS 40 37 824, in which these disadvantages are avoided.
  • This control valve is designed so that it has negative overlap in its central position. It is controlled in such a way that the pressures in the pressure chambers of the differential piston remain approximately constant and that the holding pressures when the differential piston is in a stationary position are substantially lower than the adjustment pressures.
  • Such a hydraulic actuating device is used, for example, to actuate a device for adjusting the camshaft relative to the crankshaft in an internal combustion engine (DE-OS 36 16 234).
  • control valves In order to securely seal the respective pressure-carrying connection against the return connection in the end positions of the control valve, narrow and long guide gaps are sometimes necessary for the valve member in these control valves. As a result, these control valves may be sensitive to dirt, ie if the pressure medium (engine oil of the internal combustion engine) is contaminated, the valve function can be impaired. In addition, such control valves are expensive to manufacture due to the necessary small tolerances.
  • the hydraulic actuating device according to the invention with the characterizing features of the main claim has the advantage that it works with low losses if there is no adjustment movement of the differential piston, that it is simple in construction and that the sensitivity of the control valve to dirt is low .
  • FIG. 1 shows a simplified illustration of a first exemplary embodiment of the hydraulic actuating device in FIG. 1.
  • FIG. 2 shows the pump of the hydraulic actuating device in a simplified representation
  • FIG. 3 shows the control valve of the hydraulic actuating device in a longitudinal section.
  • Figure 4 shows a second embodiment of the hydraulic actuator in a simplified representation.
  • 10 denotes a hydraulic actuating device which has a differential cylinder 11 with differential pistons 12, 13.
  • the pressure chamber 14 on the large piston surface of the differential piston 12 is connected via a pressure line 15 to a pump work chamber 16 of a pump 17 - shown in more detail in FIG. 2.
  • the pressure chamber 18 on the smaller effective piston surface of the differential piston 12 is connected via a pressure line 19 to a further pump chamber 20 of the pump 17, which acts in the opposite direction to the first pump chamber 16.
  • the pump work space 16 is supplied with pressure medium via a supply line 21 opening into the pressure line 15.
  • a check valve 22 is used, which in the pressure medium flow from the pressure medium designated P
  • the pressure medium source P is MM is, for example, a device for supplying pressure medium or lubricant to an internal combustion engine.
  • a check valve 26 and 27 is arranged in each of the pressure lines 15 and 19 between the supply line 21 and 24 and the pressure chamber 14 and 18, which opens when the pressure medium flows from the pump work chamber to the pressure chamber.
  • a control line 29 branches off from the pressure line 15 between the check valve 26 and the pressure chamber 14 and is connected to a connection 30 of a control valve 31 - shown in more detail in FIG. 3.
  • the control valve 31 is a 3/2 seat valve, from the second connection 32 of which a control line 33 emerges, which opens into the pressure line 19 - between the check valve 27 and the pressure chamber 18.
  • the third connection of the control valve is designed as a return 34 and connected to a container 35.
  • the pump 17 shown schematically in FIG. 2 is a radial piston pump with pistons operating in opposite directions, which are driven, for example, by the camshaft of an internal combustion engine via a drive shaft 36.
  • the camshaft can also be used directly as the drive shaft of the pump.
  • the two pump work spaces 16 and 20 are arranged offset from one another by 180 °, their pistons 37 and 38 are driven by an eccentric 40 arranged on the drive shaft 36.
  • the control valve 31 shown in FIG. 3 has an approximately cup-shaped housing 41, in the bottom 42 of which a central bore 43 is arranged.
  • Two sleeve-shaped extensions 44, 45 extend from the bottom 42, of which the extension 44 projects into the interior of the housing 41 and the extension 45 points in the opposite direction.
  • the extensions 44, 45 are dimensioned such that their interior spaces, together with the bore, form a cylindrical valve space 46.
  • a recess 48 extends from the free end face of the extension 45 and is closed on one side by a cover 49 resting on the end face.
  • the depression 48 extends as far as a sleeve 47, which is inserted into the valve chamber 46 and is made of a non-magnetic material. The sleeve 47 and the extension
  • transverse bore 50 which is connected to the return 34 of the control valve and via which the valve chamber
  • the housing 41 is surrounded by a cylinder jacket 51 made of non-magnetic material, which projects above the housing and is closed by a cover 52, so that an armature space 53 is formed.
  • a magnetic coil 54 is inserted into the interior of the housing 41, which comprises the sleeve-shaped extension 44 and whose inside diameter is larger than its outside diameter.
  • a compression spring 56 is inserted, one end of which rests on the bottom 42 of the housing and the other end of which rests on a disk-shaped flat armature 57 which is arranged in the armature space 53.
  • This flat armature 57 interacts with an essentially cylindrical valve member 59 which is guided in the sleeve 47.
  • the length of the valve member 59 is less than the distance between the covers 49 and 52.
  • the valve member 59 penetrates the flat armature 57 in the center and is firmly connected to it.
  • the valve member On the end face facing the cover 52, the valve member has a shoulder 60 of smaller diameter.
  • the free end face 61 of the shoulder 60 interacts with a bore 62 in the cover 52 which is designed as a valve seat and is connected to the control line 33.
  • the flat armature 57 is penetrated by a plurality of regularly arranged bores 65, which serve to pass the pressure medium through.
  • the valve member 59 projects with its end facing the cover 49 into the recess 48 and there has a shoulder 66 of smaller diameter, the end face 67 of which cooperates with a bore 68 in the cover 49 designed as a valve seat.
  • the bore 68 serves as the first connection 30 of the control valve 31 and is connected to the control line 29.
  • the valve member 59 has a section 70 of smaller diameter located within the sleeve 47, so that an annular space 71 is formed between the latter and the sleeve 47.
  • the outer sections 72 and 73 of larger diameter guide the valve member 59 in the sleeve 47 and have flattened areas 74 and 75, respectively, for the passage of the pressure medium, which pressure medium can flow past.
  • the hydraulic actuating device 10 is used, for example, in a device for continuously adjusting the camshaft of an internal combustion engine relative to its crankshaft, as a result of which a phase shift is generated between these two shafts.
  • a displacement of the differential piston 12, 13 to the left (FIG. 1) produces an adjustment of the camshaft to "late” in this device, ie to a late rotational position or later valve actuation.
  • An adjustment of the differential piston to the right consequently produces an adjustment according to "early" or earlier rotational position and earlier valve actuation.
  • the control valve 31 is switched into the second switching position by appropriate actuation of the solenoid 54, so that the shoulder 66 of the valve member 59 closes the bore 68 and thus the control line 29 on one side.
  • the opposite bore 62 is then connected to the transverse bore 50 or the return 34 and the container 35 via the armature space 53, the space between the sleeve 47 and the flats 75 of the section 73 and the annular space 71.
  • the pressure line 19 and thus the pressure chamber 18 to the container 35 are relieved, while the pressure chamber 14 is pressurized by the pump 17 via the pump working chamber 16 and the pressure line 15.
  • a stationary position of the differential piston 12, 13 is achieved by correspondingly clocked or proportional activation of the control valve 31, a pressure being set in the control line 29 and thus in the pressure chamber 14 which is just sufficient for the restoring force (acting on the adjusting device) of the differential piston.
  • the holding pressures in this stationary position of the differential piston are thus very much lower than the pressures required for a (fast) adjustment movement.
  • the described design of the hydraulic actuating device and the control valve 31 ensures that the internal combustion engine runs smoothly even if the control valve or the hydraulic supply fails.
  • the control valve 31 assumes the switch position shown in FIG. 1 due to the action of the spring 56.
  • the pressure chamber 18 is pressurized, while the pressure chamber 14 is relieved of pressure to the container 35. This moves the differential piston to the left ("late"). If the hydraulic supply fails, the differential piston 12, 13 is moved to the left due to the mechanical restoring force from the device for adjusting the camshaft. In both cases, an engine emergency run is ensured due to this reset to the late rotational position of the camshaft.
  • control valve 31 Due to the described design of the control valve 31 or the valve member 59, only the pressure of the return 34 prevails in the region of the guide of the valve member. On the one hand, the effective guide length for the valve member can be kept small, since no sealing function against higher pressures is necessary. On the other hand, there is no great pressure difference in the guide area of the valve member, through which dirt could be conveyed into the guide gap. In order to prevent metallic abrasion from accumulating due to the effect of magnetic fields in the area of the valve member, the sleeve used for guiding is made of non-magnetic material.
  • the control valve 31 can, as shown in FIG. 3, be designed with a flat armature or as a proportional solenoid valve with a suitably designed magnetic circuit.
  • control valve 31 can be used as a pressure control valve.
  • the valve member is then only pressed against the valve seat as strongly as is necessary for the corresponding generation of pressure.
  • the control valve with a suitably designed magnetic circuit as a proportional solenoid valve, since the adjusting forces differ depending on the speed of the drive shaft.
  • the solenoid 54 is then actuated so that the pressure in the control line 29 and thus in the pressure chamber 14 maintains the equilibrium with the restoring forces acting on the differential piston.
  • the pump 17 is throttled on the suction side. B. via a slot-controlled intake throttling.
  • This makes it possible to implement a flow rate curve that is constant over the entire speed range of the internal combustion engine or the drive shaft.
  • the pump or the intake throttling is designed so that the beginning of the constant delivery range (constant flow of conveying medium) coincides with the lower limit speed of the working range (e.g. idle speed of the internal combustion engine).
  • the pump delivery rate is matched to the required adjustment speed of the differential cylinder.
  • the control valve 31 is designed as a simple solenoid valve with a flat armature, since a pressure control function - as described above - is not required.
  • the speed of adjustment of the differential piston can be influenced by clocking the solenoid valve.
  • the holding function stationary position of the differential cylinder
  • the control valve can also be realized by correspondingly timed control of the control valve.
  • the pressure medium supply of the pump is expediently from a reservoir (container).
  • a pump 17a feeds into a common delivery line 80, from which two pressure lines 81, 82 originate.
  • a pressure-controlled check valve 83, 84 is connected to each of the two pressure lines 81, 82 for reversing the pump delivery flow.
  • the check valve 83 is connected on the outlet side to the pressure line 15 and the check valve 84 to the pressure line 19.
  • the check valves 83, 84 are designed so that they open when there is a pressure medium flow from the pump 16a to the differential cylinder 11.
  • the respective valve members 85, 86 are each acted upon by a compression spring 87 or 88 and additionally by the pressure in a control line 89 or 90.
  • the control line 89 on the check valve 83 is connected to the pressure line 19, while the control line 90 on the check valve 84 leads to the pressure line 15.
  • a throttle 91 is inserted between the control line 90 and the check valve 83 in the pressure line 15.
  • a throttle 92 is also inserted into the pressure line 19, namely between the check valve 84 and the control line 89.
  • the control valve 31 is connected via the control lines 29 and 33 to the pressure lines 15 and 19, respectively between the control lines 90 and 89 leading to the check valves and the differential cylinder 11.
  • both check valves 83, 84 can open when the actuating device is initially depressurized and the pump 17a starts.
  • a certain pressure builds up in front of the throttles 91 and 92 in the pressure lines 81, 82 and in the pressure lines 15 and 19, which pressure also prevails in the pressure line 19 behind the throttle 92. Due to the relief of the pressure line 15 to the container via the control valve 31, no such pressure can build up behind the throttle 91.
  • the pressure in the pressure line 19 also acts on the check valve 83 via the control line 89, so that the check valve 83 is closed due to the additional force of the compression spring 87. Due to the pressure building up in the pressure chamber 18 and due to the relief of the pressure chamber 14 to the container 35 the differential piston is moved to the left ("late").
  • control valve 31 In order to produce an adjustment of the differential piston to the right ("early"), the control valve 31 is moved into the second switching position by appropriate excitation of the solenoid coil, so that the pressure line 19 to the container is relieved. In accordance with the switching position described above, the check valve 84 is then moved into the closed position, so that when the pressure chamber 18 and pressure chamber 14 are relieved of pressure, the differential piston moves to the right.
  • the stop position (stationary position of the differential piston) can be achieved either by appropriately clocked control of the control valve or by pressure control with a partially excited solenoid.
  • the pressure drop at the throttles 91 and 92 should be limited to, for example, 5 to 10 bar.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Valve Device For Special Equipments (AREA)

Abstract

L'organe de réglage hydraulique (10) possède un cylindre différentiel (11) dont les chambres de pression (14, 18) sont alimentées chacune par une pompe (17). Les conduites de refoulement (15 et 19) entre la pompe et les deux chambres de pression (14 et 18) sont reliées par des conduites de pilotage (29 et 33) à la soupape de commande (31). Par un pilotage correspondant de la soupape de commande, il est possible de régler une pression partielle dans les chambres de pression (14 et 18) par l'écoulement de fluide hydraulique.The hydraulic adjustment member (10) has a differential cylinder (11), the pressure chambers (14, 18) of which are each supplied by a pump (17). The delivery lines (15 and 19) between the pump and the two pressure chambers (14 and 18) are connected by pilot lines (29 and 33) to the control valve (31). By corresponding actuation of the control valve, it is possible to set a partial pressure in the pressure chambers (14 and 18) by the flow of hydraulic fluid.

Description

Hydraulische StelleinrichtungHydraulic actuator
Stand der TechnikState of the art
Die Erfindung geht aus von einer hydraulischen Stelleinrichtung nach der Gattung des Hauptanspruchs. Aus der US-PS 3 516 331 ist eine hy¬ draulische Stelleinrichtung mit einem Differentialzylinder bekannt, dessen der größeren wirksamen Druckfläche des Differentialkolbens zugeordneter Druckraum über ein 3/2-Wegeventil angesteuert wird. Über entsprechendes Takten des 3/2-Wegeventils kann eine Druck¬ differenz in den beiden Druckräumen erzeugt werden, die eine Ver¬ stellbewegung hervorruft. Eine derartige hydraulische Stellein¬ richtung hat den Nachteil, daß bei stationärem, d. h. unbewegtem, Differentialkolben in den Druckräumen relativ hohe Drücke anstehen, die nicht oder nur wenig kleiner als die Verstelldrücke sind. Da¬ durch ist in der Halteposition (stationäre Stellung) des Differen¬ tialkolbens ein hoher Energieaufwand nötig, der im Betrieb der hy¬ draulischen Stelleinrichtung zu hohen Kosten führen kann.The invention is based on a hydraulic actuator according to the preamble of the main claim. From US Pat. No. 3,516,331, a hydraulic actuating device with a differential cylinder is known, the pressure chamber of which is assigned to the larger effective pressure surface of the differential piston and is controlled via a 3/2-way valve. By correspondingly clocking the 3/2-way valve, a pressure difference can be generated in the two pressure spaces, which causes an adjustment movement. Such a hydraulic actuating device has the disadvantage that with stationary, ie. H. Non-moving differential pistons in the pressure chambers are subject to relatively high pressures, which are not or only slightly less than the adjustment pressures. As a result, in the holding position (stationary position) of the differential piston, a high expenditure of energy is necessary, which can lead to high costs in the operation of the hydraulic actuating device.
Aus der DE-OS 40 37 824 ist eine hydraulische Stelleinrichtung be¬ kannt, bei der diese Nachteile vermieden werden. Bei dieser be¬ kannten hydraulischen Stelleinrichtung wird der an der großen Kolbenfläche eines Differentialzylinders angeordnete Druckraum über ein elektromagnetisch betätigbares Steuerventil angesteuert. Dieses Steuerventil ist so ausgebildet, daß es in seiner Mittelstellung negative Überdeckung hat. Es wird so angesteuert, daß die Drücke in den Druckräumen des Differentialkolbens annähernd konstant bleiben und daß die Haltedrücke bei stationärer Stellung des Differential¬ kolbens wesentlich kleiner sind als die Verstelldrücke. Eine der¬ artige hydraulische Stelleinrichtung wird beispielsweise eingesetzt, um in einer Brennkraftmaschine eine Einrichtung zur Verstellung der Nockenwelle relativ zur Kurbelwelle zu betätigen (DE-OS 36 16 234). Um in den Endstellungen des Steuerventils den jeweiligen druck- führenden Anschluß gegen den Rücklaufanschluß sicher abzudichten, sind bei diesen Steuerventilen zum Teil enge und lange Führungs¬ spalte für das Ventilglied notwendig. Dadurch sind diese Steuer¬ ventile unter Umstanden schmutzempfindlich, d. h. bei verschmutztem Druckmittel (Motoröl der Brennkraftmaschine) kann die Ventilfunktion beeinträchtigt werden. Darüber hinaus sind derartige Steuerventile aufgrund der notwendigen geringen Toleranzen aufwendig zu fertigen.A hydraulic actuating device is known from DE-OS 40 37 824, in which these disadvantages are avoided. In this known hydraulic actuating device, the large one Piston surface of a differential cylinder arranged pressure chamber controlled via an electromagnetically actuated control valve. This control valve is designed so that it has negative overlap in its central position. It is controlled in such a way that the pressures in the pressure chambers of the differential piston remain approximately constant and that the holding pressures when the differential piston is in a stationary position are substantially lower than the adjustment pressures. Such a hydraulic actuating device is used, for example, to actuate a device for adjusting the camshaft relative to the crankshaft in an internal combustion engine (DE-OS 36 16 234). In order to securely seal the respective pressure-carrying connection against the return connection in the end positions of the control valve, narrow and long guide gaps are sometimes necessary for the valve member in these control valves. As a result, these control valves may be sensitive to dirt, ie if the pressure medium (engine oil of the internal combustion engine) is contaminated, the valve function can be impaired. In addition, such control valves are expensive to manufacture due to the necessary small tolerances.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße hydraulische Stelleinrichtung mit den kenn¬ zeichnenden Merkmalen des Hauptanspruchs hat demgegenüber den Vor¬ teil, daß sie mit geringen Verlusten arbeitet, wenn keine Verstell¬ bewegung des Differentialkolbens erfolgt, daß sie einfach aufgebaut ist und daß die Verschmutzungsempfindlichkeit des Steuerventils ge¬ ring ist.The hydraulic actuating device according to the invention with the characterizing features of the main claim has the advantage that it works with low losses if there is no adjustment movement of the differential piston, that it is simple in construction and that the sensitivity of the control valve to dirt is low .
Weitere Vorteile der Erfindung und vorteilhafte Weiterbildungen er¬ geben sich aus den Unteransprüchen und der Beschreibung. ZeichnungFurther advantages of the invention and advantageous developments result from the subclaims and the description. drawing
Zwei Ausführungsbeispiele der Erfindung sind in der nachfolgenden Beschreibung und Zeichnung näher erläutert. Letztere zeigt in Fi¬ gur 1 ein erstes Ausführungsbeispiel der hydraulischen Stellein¬ richtung in vereinfachter Darstellung. Figur 2 zeigt die Pumpe der hydraulischen Stelleinrichtung in vereinfachter Darstellung und Fi¬ gur 3 das Steuerventil der hydraulischen Stelleinrichtung im Längs¬ schnitt. Figur 4 zeigt ein zweites Ausführungsbeispiel der hydrau¬ lischen Stelleinrichtung in vereinfachter Darstellung.Two embodiments of the invention are explained in more detail in the following description and drawing. The latter shows a simplified illustration of a first exemplary embodiment of the hydraulic actuating device in FIG. 1. FIG. 2 shows the pump of the hydraulic actuating device in a simplified representation, and FIG. 3 shows the control valve of the hydraulic actuating device in a longitudinal section. Figure 4 shows a second embodiment of the hydraulic actuator in a simplified representation.
Beschreibung der AusführungsbeispieleDescription of the embodiments
In Figur 1 ist mit 10 eine hydraulische Stelleinrichtung bezeichnet, die einen Differentialzylinder 11 mit Differentialkolben 12, 13 auf¬ weist. Der Druckraum 14 an der großen Kolbenfläche des Differential¬ kolbens 12 ist über eine Druckleitung 15 mit einem Pumpenarbeitsraum 16 einer - in Figur 2 näher dargestellten - Pumpe 17 verbunden. Der Druckraum 18 an der kleineren wirksamen Kolbenfläche des Differen¬ tialkolbens 12 ist über eine Druckleitung 19 mit einem weiteren, gegensinnig zum ersten Pumpenarbeitsraum 16 wirkenden, Pumpen¬ arbeitsraum 20 der Pumpe 17 verbunden.In FIG. 1, 10 denotes a hydraulic actuating device which has a differential cylinder 11 with differential pistons 12, 13. The pressure chamber 14 on the large piston surface of the differential piston 12 is connected via a pressure line 15 to a pump work chamber 16 of a pump 17 - shown in more detail in FIG. 2. The pressure chamber 18 on the smaller effective piston surface of the differential piston 12 is connected via a pressure line 19 to a further pump chamber 20 of the pump 17, which acts in the opposite direction to the first pump chamber 16.
Der Pumpenarbeitsraum 16 wird über eine in die Druckleitung 15 mündende Versorgungsleitung 21 mit Druckmittel versorgt. In dieseThe pump work space 16 is supplied with pressure medium via a supply line 21 opening into the pressure line 15. In these
Versorgungsleitung 21 ist ein Rückschlagventil 22 eingesetzt, das bei Druckmittelströmung von der mit P bezeichneten Druckmittel-Supply line 21, a check valve 22 is used, which in the pressure medium flow from the pressure medium designated P
M quelle zum Pumpenarbeitsraum 16 öffnet. Auf analoge Weise ist derM source to the pump work space 16 opens. The analog is
Pumpenarbeitsräum 20 über eine in die Druckmittelleitung 19 mündendePump work room 20 via a mouth opening in the pressure medium line 19
Versorgungsleitung 24 mit Rückschlagventil 25 mit der Druckmittel- guelle P verbunden. Bei der Druckmittelquelle P handelt es M M sich beispielsweise um eine Einrichtung zur Druckmittel- bzw. Schmiermittelversorgung einer Brennkraftmaschine.Supply line 24 with check valve 25 connected to the pressure medium source P. The pressure medium source P is MM is, for example, a device for supplying pressure medium or lubricant to an internal combustion engine.
In den Druckleitungen 15 bzw. 19 ist jeweils zwischen Versorgungs¬ leitung 21 bzw. 24 und dem Druckraum 14 bzw. 18 ein Rückschlagventil 26 bzw. 27 angeordnet, das bei einer Druckmittelströmung vom Pumpen¬ arbeitsraum zum Druckraum öffnet.A check valve 26 and 27 is arranged in each of the pressure lines 15 and 19 between the supply line 21 and 24 and the pressure chamber 14 and 18, which opens when the pressure medium flows from the pump work chamber to the pressure chamber.
Von der Druckleitung 15 zweigt zwischen dem Rückschlagventil 26 und dem Druckraum 14 eine Steuerleitung 29 ab, die mit einem Anschluß 30 eines - in Figur 3 näher dargestellten - Steuerventils 31 verbunden ist. Bei dem Steuerventil 31 handelt es sich im Ausführungsbeispiel um ein 3/2-Sitzventil, von dessen zweitem Anschluß 32 eine Steuer¬ leitung 33 ausgeht, die in die Druckleitung 19 - zwischen Rück¬ schlagventil 27 und Druckraum 18 - mündet. Der dritte Anschluß des Steuerventils ist als Rücklauf 34 ausgebildet und mit einem Behälter 35 verbunden.A control line 29 branches off from the pressure line 15 between the check valve 26 and the pressure chamber 14 and is connected to a connection 30 of a control valve 31 - shown in more detail in FIG. 3. In the exemplary embodiment, the control valve 31 is a 3/2 seat valve, from the second connection 32 of which a control line 33 emerges, which opens into the pressure line 19 - between the check valve 27 and the pressure chamber 18. The third connection of the control valve is designed as a return 34 and connected to a container 35.
Bei der in Figur 2 schematisch dargestellten Pumpe 17 handelt es sich im Ausführungsbeispiel um eine Radialkolbenpumpe mit gegen¬ sinnig arbeitenden Kolben, die über eine Antriebswelle 36 beispiels¬ weise von der Nockenwelle eines Verbrennungsmotors angetrieben wer¬ den. Beim Einsatz der hydraulischen Stelleinrichtung z. B. zur Ver¬ stellung der Nockenwelle eines Kraftfahrzeuges relativ zu dessen Kurbelwelle (DE-OS 36 16 234) kann als Antriebswelle der Pumpe auch direkt die Nockenwelle genutzt werden. Die zwei Pumpenarbeitsräume 16 und 20 sind um 180° gegeneinander versetzt angeordnet, ihre Kol¬ ben 37 bzw. 38 werden über einen auf der Antriebswelle 36 angeordne¬ ten Exzenter 40 angetrieben. Das in Figur 3 dargestellte Steuerventil 31 hat ein etwa topfförmi- ges Gehäuse 41, in dessen Boden 42 eine mittige Bohrung 43 ange¬ ordnet ist. Vom Boden 42 gehen zwei hülsenförmige Fortsätze 44, 45 aus, von denen der Fortsatz 44 ins Innere des Gehäuses 41 ragt und der Fortsatz 45 in die entgegengesetzte Richtung weist. Die Fort¬ sätze 44, 45 sind so bemessen, daß ihre Innenräume zusammen mit der Bohrung einen zylinderförmigen Ventilraum 46 ausbilden.In the exemplary embodiment, the pump 17 shown schematically in FIG. 2 is a radial piston pump with pistons operating in opposite directions, which are driven, for example, by the camshaft of an internal combustion engine via a drive shaft 36. When using the hydraulic actuator z. B. for adjusting the camshaft of a motor vehicle relative to its crankshaft (DE-OS 36 16 234), the camshaft can also be used directly as the drive shaft of the pump. The two pump work spaces 16 and 20 are arranged offset from one another by 180 °, their pistons 37 and 38 are driven by an eccentric 40 arranged on the drive shaft 36. The control valve 31 shown in FIG. 3 has an approximately cup-shaped housing 41, in the bottom 42 of which a central bore 43 is arranged. Two sleeve-shaped extensions 44, 45 extend from the bottom 42, of which the extension 44 projects into the interior of the housing 41 and the extension 45 points in the opposite direction. The extensions 44, 45 are dimensioned such that their interior spaces, together with the bore, form a cylindrical valve space 46.
Von der freien Stirnseite des Fortsatzes 45 geht eine Vertiefung 48 aus, die durch einen an der Stirnseite anliegenden Deckel 49 ein¬ seitig verschlossen ist. Die Vertiefung 48 reicht bis an eine Hülse 47 heran, die in den Ventilraum 46 eingesetzt, und aus einem nicht¬ magnetischen Material gefertigt ist. Die Hülse 47 und der FortsatzA recess 48 extends from the free end face of the extension 45 and is closed on one side by a cover 49 resting on the end face. The depression 48 extends as far as a sleeve 47, which is inserted into the valve chamber 46 and is made of a non-magnetic material. The sleeve 47 and the extension
45 werden von einer Querbohrung 50 durchdrungen, die mit dem Rück¬ lauf 34 des Steuerventils verbunden ist und über die der Ventilraum45 are penetrated by a transverse bore 50 which is connected to the return 34 of the control valve and via which the valve chamber
46 mit dem Behälter 35 verbunden ist.46 is connected to the container 35.
Das Gehäuse 41 ist von einem Zylindermantel 51 aus unmagnetischem Werkstoff umgeben, der das Gehäuse nach oben überragt und durch einen Deckel 52 verschlossen ist, so daß ein Ankerraum 53 ausge¬ bildet ist.The housing 41 is surrounded by a cylinder jacket 51 made of non-magnetic material, which projects above the housing and is closed by a cover 52, so that an armature space 53 is formed.
In das Innere des Gehäuses 41 ist eine Magnetspule 54 eingesetzt, die den hülsenförmigen Fortsatz 44 umfaßt, und deren Innendurch¬ messer größer als dessen Außendurchmesser ist. In den zwischen Mag¬ netspule 54 und Fortsatz 44 gebildeten Ringraum 55 ist eine Druck¬ feder 56 eingesetzt, deren eines Ende am Boden 42 des Gehäuses und deren anderes Ende an einem scheibenförmigen Flachanker 57 anliegt, der im Ankerraum 53 angeordnet ist. Dieser Flachanker 57 wirkt mit einem im wesentlichen zylinder- förmigen Ventilglied 59 zusammen, das in der Hülse 47 geführt ist. Die Länge des Ventilgliedes 59 ist geringer als der Abstand der Deckel 49 und 52. Das Ventilglied 59 durchdringt den Flachanker 57 mittig und ist fest mit diesem verbunden. An der dem Deckel 52 zuge¬ wandten Stirnseite hat das Ventilglied einen Absatz 60 geringeren Durchmessers. Die freie Stirnseite 61 des Absatzes 60 wirkt mit einer als Ventilsitz ausgebildeten Bohrung 62 im Deckel 52 zusammen, die mit der Steuerleitung 33 verbunden ist.A magnetic coil 54 is inserted into the interior of the housing 41, which comprises the sleeve-shaped extension 44 and whose inside diameter is larger than its outside diameter. In the annular space 55 formed between the magnet coil 54 and the extension 44, a compression spring 56 is inserted, one end of which rests on the bottom 42 of the housing and the other end of which rests on a disk-shaped flat armature 57 which is arranged in the armature space 53. This flat armature 57 interacts with an essentially cylindrical valve member 59 which is guided in the sleeve 47. The length of the valve member 59 is less than the distance between the covers 49 and 52. The valve member 59 penetrates the flat armature 57 in the center and is firmly connected to it. On the end face facing the cover 52, the valve member has a shoulder 60 of smaller diameter. The free end face 61 of the shoulder 60 interacts with a bore 62 in the cover 52 which is designed as a valve seat and is connected to the control line 33.
Um das Ventilglied 59 herum wird der Flachanker 57 von mehreren, re¬ gelmäßig angeordneten Bohrungen 65 durchdrungen, die der Druck¬ mitteldurchführung dienen.Around the valve member 59, the flat armature 57 is penetrated by a plurality of regularly arranged bores 65, which serve to pass the pressure medium through.
Das Ventilglied 59 ragt mit seinem dem Deckel 49 zugewandten Ende bis in die Vertiefung 48 und hat dort einen Absatz 66 geringeren Durchmessers, dessen Stirnseite 67 mit einer als Ventilsitz aus¬ gebildeten Bohrung 68 im Deckel 49 zusammenwirkt. Die Bohrung 68 dient als erster Anschluß 30 des Steuerventils 31 und ist mit der Steuerleitung 29 verbunden.The valve member 59 projects with its end facing the cover 49 into the recess 48 and there has a shoulder 66 of smaller diameter, the end face 67 of which cooperates with a bore 68 in the cover 49 designed as a valve seat. The bore 68 serves as the first connection 30 of the control valve 31 and is connected to the control line 29.
Das Ventilglied 59 hat einen innerhalb der Hülse 47 befindlichen Ab¬ schnitt 70 geringeren Durchmessers, so daß zwischen diesem und der Hülse 47 ein Ringraum 71 ausgebildet ist. Die äußeren Abschnitte 72 und 73 größeren Durchmessers führen das Ventilglied 59 in der Hülse 47 und haben zur Druckmitteldurchführung dienende abgeflachte Be¬ reiche 74 bzw. 75, an denen Druckmittel vorbeiströmen kann.The valve member 59 has a section 70 of smaller diameter located within the sleeve 47, so that an annular space 71 is formed between the latter and the sleeve 47. The outer sections 72 and 73 of larger diameter guide the valve member 59 in the sleeve 47 and have flattened areas 74 and 75, respectively, for the passage of the pressure medium, which pressure medium can flow past.
Die hydraulische Stelleinrichtung 10 ist beispielsweise in einer Einrichtung zur stetigen Verstellung der Nockenwelle einer Brenn¬ kraftmaschine relativ zu deren Kurbelwelle eingesetzt, wodurch eine Phasenverschiebung zwischen diesen beiden Wellen erzeugt wird. Eine Verschiebung des Differentialkolbens 12, 13 nach links (Figur 1) erzeugt in dieser Einrichtung eine Verstellung der Nockenwelle nach "spät", d. h. zu einer späten Drehlage bzw. später Ventilbetä¬ tigung. Eine Verstellung des Differentialkolbens nach rechts erzeugt demzufolge eine Verstellung nach "früh" bzw. früher Drehlage und früher Ventilbetätigung.The hydraulic actuating device 10 is used, for example, in a device for continuously adjusting the camshaft of an internal combustion engine relative to its crankshaft, as a result of which a phase shift is generated between these two shafts. A displacement of the differential piston 12, 13 to the left (FIG. 1) produces an adjustment of the camshaft to "late" in this device, ie to a late rotational position or later valve actuation. An adjustment of the differential piston to the right consequently produces an adjustment according to "early" or earlier rotational position and earlier valve actuation.
Bei der in Figur 1 dargestellten Schaltstellung des stromlosen Steuerventils 31 ist die Steuerleitung 29 mit dem Behälter 34 ver¬ bunden, während die Steuerleitung 33 durch das Steuerventil 31 ein¬ seitig verschlossen ist. In dieser Schaltstellung liegt der in Figur 3 dargestellte Absatz 60 des Ventilgliedes 59 aufgrund der Wirkung der Druckfeder 56 an der mit der Steuerleitung 33 verbundenene Bohrung 62 an und verschließt diese. Gleichzeitig kann Druckmittel von der Steuerleitung 29 durch die Bohrung 68 in die Vertiefung 48 gelangen. Von dort besteht eine Verbindung zur Querbohrung 50 und damit zum Behälter 35, und zwar über den Raum zwischen Hülse 47 und den abgeflachten Bereichen 74 des Abschnittes 72 und über den Ring¬ raum 71. Damit ist die Druckleitung 15 und somit auch der Druckraum 14 des Differentialzylinders 11 zum Behälter 34 entlastet, während der Druckraum 18 von der Pumpe 17 über den Pumpenarbeitsraum 20 mit Druck beaufschlagt wird. Der Differentialkolben 12, 13 wird nach links bewegt.In the switching position of the currentless control valve 31 shown in FIG. 1, the control line 29 is connected to the container 34, while the control line 33 is closed on one side by the control valve 31. In this switching position, the shoulder 60 of the valve member 59 shown in FIG. 3 lies against the bore 62 connected to the control line 33 due to the action of the compression spring 56 and closes it. At the same time, pressure medium can get from the control line 29 through the bore 68 into the depression 48. From there, there is a connection to the transverse bore 50 and thus to the container 35, specifically via the space between the sleeve 47 and the flattened regions 74 of the section 72 and via the annular space 71. The pressure line 15 and thus also the pressure space 14 of the Differential cylinder 11 to the container 34 is relieved, while the pressure chamber 18 is pressurized by the pump 17 via the pump work chamber 20. The differential piston 12, 13 is moved to the left.
Soll der Differentialkolben 12, 13 nach rechts bewegt werden, wird das Steuerventil 31 durch entsprechende Ansteuerung der Magnetspule 54 in die zweite Schaltstellung geschaltet, so daß der Absatz 66 des Ventilgliedes 59 die Bohrung 68 und damit die Steuerleitung 29 ein¬ seitig verschließt. Dadurch ist dann die gegenüberliegende Bohrung 62 über den Ankerraum 53, den Raum zwischen Hülse 47 und den Ab¬ flachungen 75 des Abschnittes 73 sowie über den Ringraum 71 mit der Querbohrung 50 bzw. dem Rücklauf 34 und dem Behälter 35 verbunden. In dieser Schaltstellung ist die Druckleitung 19 und damit der Druckraum 18 zum Behälter 35 entlastet, während der Druckraum 14 von der Pumpe 17 über den Pumpenarbeitsraum 16 und die Druckleitung 15 mit Druck beaufschlagt wird.If the differential piston 12, 13 is to be moved to the right, the control valve 31 is switched into the second switching position by appropriate actuation of the solenoid 54, so that the shoulder 66 of the valve member 59 closes the bore 68 and thus the control line 29 on one side. As a result, the opposite bore 62 is then connected to the transverse bore 50 or the return 34 and the container 35 via the armature space 53, the space between the sleeve 47 and the flats 75 of the section 73 and the annular space 71. In this switching position, the pressure line 19 and thus the pressure chamber 18 to the container 35 are relieved, while the pressure chamber 14 is pressurized by the pump 17 via the pump working chamber 16 and the pressure line 15.
Eine st tionäre Stellung des Differentialkolbens 12, 13 wird durch entsprechend getaktetes oder proportionales Ansteuern des Steuer¬ ventils 31 erreicht, wobei in der Steuerleitung 29 und damit im Druckraum 14 ein Druck eingestellt wird, der gerade ausreicht, die (von der VerStelleinrichtung einwirkende) Rückstellkraft des Differentialkolbens auszugleichen. Die Haltedrücke in dieser statio¬ nären Stellung des Differentialkolbens sind somit sehr viel geringer als die für eine (schnelle) Verstellbewegung benötigten Drücke.A stationary position of the differential piston 12, 13 is achieved by correspondingly clocked or proportional activation of the control valve 31, a pressure being set in the control line 29 and thus in the pressure chamber 14 which is just sufficient for the restoring force (acting on the adjusting device) of the differential piston. The holding pressures in this stationary position of the differential piston are thus very much lower than the pressures required for a (fast) adjustment movement.
Über entsprechende Ansteuerung der Magnetspule wird ebenfalls ge¬ währleistet, daß diese Haltedrücke auch bei sich ändernden Dreh¬ zahlen der Nockenwelle auf einem Niveau gehalten werden, das gerade ausreicht, die Rückstellkräfte aus der Einrichtung zur Verstellung der Nockenwelle aufzunehmen.Appropriate control of the solenoid coil also ensures that these holding pressures are maintained at a level which is just sufficient to absorb the restoring forces from the device for adjusting the camshaft, even when the camshaft speeds change.
Durch die beschriebene Ausbildung der hydraulischen Stelleinrichtung und des Steuerventils 31 ist ein Motornotlauf der Brennkraftmaschine auch bei Ausfall des Steuerventils bzw. der Hydraulikversorgung ge¬ währleistet. Im nicht angesteuerten Zustand nimmt das Steuerventil 31 aufgrund der Wirkung der Feder 56 die in Figur 1 dargestellte Schaltstellung ein. Dadurch ist - wie zuvor beschrieben - der Druck¬ raum 18 mit Druck beaufschlagt, während der Druckraum 14 zum Be¬ hälter 35 entlastet ist. Damit wird der Differentialkolben nach links ("spät") verstellt. Bei Ausfall der Hydraulikversorgung wird der Differentialkolben 12, 13 aufgrund der mechanischen Rückstell¬ kraft aus der Einrichtung zur Verstellung der Nockenwelle nach links bewegt. In beiden Fällen ist aufgrund dieser Rückstellung zur späten Drehlage der Nockenwelle ein Motornotlauf gesichert. Durch die beschriebene Ausbildung des Steuerventils 31 bzw. des Ventilgliedes 59 herrscht im Bereich der Führung des Ventilgliedes nur der Druck des Rücklaufes 34. Dadurch kann zum einen die wirksame Führungslänge für das Ventilglied klein gehalten werden, da keine Dichtfunktion gegen höhere Drucke notwendig ist. Andererseits tritt im Führungsbereich des Ventilgliedes keine große Druckdifferenz auf, durch die Schmutz in die Führungsspalte gefördert werden könnte. Um zu vermeiden, daß sich metallischer Abrieb durch die Wirkung magne¬ tischer Felder im Bereich des Ventilgliedes anlagert, ist die zur Führung dienende Hülse aus nichtmagnetischem Material gefertigt. Das Steuerventil 31 kann, wie in Figur 3 dargestellt, mit einem Flach¬ anker oder auch als Proportionalmagnetventil mit entsprechend ausge¬ bildetem magnetischem Kreis ausgeführt sein.The described design of the hydraulic actuating device and the control valve 31 ensures that the internal combustion engine runs smoothly even if the control valve or the hydraulic supply fails. In the non-activated state, the control valve 31 assumes the switch position shown in FIG. 1 due to the action of the spring 56. As a result, as previously described, the pressure chamber 18 is pressurized, while the pressure chamber 14 is relieved of pressure to the container 35. This moves the differential piston to the left ("late"). If the hydraulic supply fails, the differential piston 12, 13 is moved to the left due to the mechanical restoring force from the device for adjusting the camshaft. In both cases, an engine emergency run is ensured due to this reset to the late rotational position of the camshaft. Due to the described design of the control valve 31 or the valve member 59, only the pressure of the return 34 prevails in the region of the guide of the valve member. On the one hand, the effective guide length for the valve member can be kept small, since no sealing function against higher pressures is necessary. On the other hand, there is no great pressure difference in the guide area of the valve member, through which dirt could be conveyed into the guide gap. In order to prevent metallic abrasion from accumulating due to the effect of magnetic fields in the area of the valve member, the sleeve used for guiding is made of non-magnetic material. The control valve 31 can, as shown in FIG. 3, be designed with a flat armature or as a proportional solenoid valve with a suitably designed magnetic circuit.
Um die Verstellgeschwindigkeit des Differentialkolbens über den ge¬ samten Drehzahlbereich der Brennkraftmaschine bzw. der Antriebswelle 36 konstant zu halten, kann das Steuerventil 31 als Druckregelventil verwendet werden. Durch entsprechende Dosierung der Magnetkraft (entsprechende Ansteuerung der Magnetspule) wird das Ventilglied dann nur so stark an den Ventilsitz gedrückt, wie es zur entsprech¬ enden Druckerzeugung notwendig ist. Dabei ist es vorteilhaft, das Steuerventil mit entsprechend ausgebildetem Magnetkreis als Propor¬ tionalmagnetventil auszubilden, da in Abhängigkeit von der Drehzahl der Antriebswelle die Verstellkräfte unterschiedlich sind. Um den Differentialkolben 12, 13 in stationärer Stellung zu halten, wird die Magnetspule 54 dann gerade so angesteuert, daß der Druck in der Steuerleitung 29 und damit im Druckraum 14 gerade den auf den Differentialkolben wirkenden Rückstellkräften das Gleichgewicht hält. In einer vorteilhaften Ausgestaltung des ersten Ausführungsbeispiels der hydraulischen Stelleinrichtung ist die Pumpe 17 saugseitig ge¬ drosselt, z. B. über eine schlitzgesteuerte Ansaugdrosselung. Damit läßt sich ein Fördermengenverlauf realisieren, der über den gesamten Drehzahlbereich der Brennkraftmaschine bzw. der Antriebswelle kon¬ stant ist. Die Auslegung der Pumpe bzw. der Ansaugdrosselung erfolgt so, daß der Beginn des Konstantförderbereiches (konstanter Förder¬ mittelstrom) mit der unteren Grenzdrehzahl des Arbeitsbereiches zu¬ sammenfällt (z. B. Leerlaufdrehzahl der Brennkraftmaschine). Die Förderrate der Pumpe ist auf die erforderliche Verstellgeschwindig¬ keit des Differentialzylinders abgestimmt. Das Steuerventil 31 ist dabei als einfaches Magnetventil mit Flachanker ausgeführt, da eine Druckregelfunktion - wie zuvor beschrieben - nicht erforderlich ist. Unabhängig davon kann die Verstellgeschwindigkeit des Differential¬ kolbens durch Takten des Magnetventils beeinflußt werden. Auch die Haltefunktion (stationäre Stellung des Differentialzylinders) kann durch entsprechende getaktete Ansteuerung des Steuerventils reali¬ siert werden. Um im Konstantförderbereich der Pumpe unterschiedliche Füllungen der Pumpenarbeits äume durch Schwankungen in der Druck¬ mittelzufuhr zu vermeiden, erfolgt die Druckmittelversorgung der Pumpe zweckmäßigerweise aus einem Reservoir (Behälter) .In order to keep the adjustment speed of the differential piston constant over the entire speed range of the internal combustion engine or the drive shaft 36, the control valve 31 can be used as a pressure control valve. By appropriate metering of the magnetic force (corresponding control of the magnetic coil), the valve member is then only pressed against the valve seat as strongly as is necessary for the corresponding generation of pressure. It is advantageous to design the control valve with a suitably designed magnetic circuit as a proportional solenoid valve, since the adjusting forces differ depending on the speed of the drive shaft. In order to keep the differential piston 12, 13 in a stationary position, the solenoid 54 is then actuated so that the pressure in the control line 29 and thus in the pressure chamber 14 maintains the equilibrium with the restoring forces acting on the differential piston. In an advantageous embodiment of the first exemplary embodiment of the hydraulic actuating device, the pump 17 is throttled on the suction side. B. via a slot-controlled intake throttling. This makes it possible to implement a flow rate curve that is constant over the entire speed range of the internal combustion engine or the drive shaft. The pump or the intake throttling is designed so that the beginning of the constant delivery range (constant flow of conveying medium) coincides with the lower limit speed of the working range (e.g. idle speed of the internal combustion engine). The pump delivery rate is matched to the required adjustment speed of the differential cylinder. The control valve 31 is designed as a simple solenoid valve with a flat armature, since a pressure control function - as described above - is not required. Irrespective of this, the speed of adjustment of the differential piston can be influenced by clocking the solenoid valve. The holding function (stationary position of the differential cylinder) can also be realized by correspondingly timed control of the control valve. In order to avoid different fillings of the pump work spaces in the constant delivery area of the pump due to fluctuations in the pressure medium supply, the pressure medium supply of the pump is expediently from a reservoir (container).
Bei dem in Figur 4 dargestellten zweiten Ausführungsbeispiel der hydraulischen Stelleinrichtung fördert eine Pumpe 17a in eine ge¬ meinsame Förderleitung 80, von der zwei Druckleitungen 81, 82 aus¬ gehen. Zur Umsteuerung des Pumpenförderstroms ist an die zwei Druck¬ leitungen 81, 82 jeweils ein druckgesteuertes Rückschlagventil 83, 84 angeschlossen. Das Rückschlagventil 83 ist ausgangsseitig mit der Druckleitung 15 und das Rückschlagventil 84 mit der Druckleitung 19 verbunden. Die Rückschlagventile 83, 84 sind so ausgebildet, daß sie bei einer Druckmittelströmung von der Pumpe 16a zum Differential- zylinder 11 öffnen. Dazu sind die jeweiligen Ventilglieder 85, 86 durch je eine Druckfeder 87 bzw. 88 und zusätzlich durch den Druck in einer Steuerleitung 89 bzw. 90 beaufschlagt. Die Steuerleitung 89 am Rückschlagventil 83 ist andererseits mit der Druckleitung 19 ver¬ bunden, während die Steuerleitung 90 am Rückschlagventil 84 zur Druckleitung 15 führt.In the second exemplary embodiment of the hydraulic actuating device shown in FIG. 4, a pump 17a feeds into a common delivery line 80, from which two pressure lines 81, 82 originate. A pressure-controlled check valve 83, 84 is connected to each of the two pressure lines 81, 82 for reversing the pump delivery flow. The check valve 83 is connected on the outlet side to the pressure line 15 and the check valve 84 to the pressure line 19. The check valves 83, 84 are designed so that they open when there is a pressure medium flow from the pump 16a to the differential cylinder 11. For this purpose, the respective valve members 85, 86 are each acted upon by a compression spring 87 or 88 and additionally by the pressure in a control line 89 or 90. The control line 89 on the check valve 83, on the other hand, is connected to the pressure line 19, while the control line 90 on the check valve 84 leads to the pressure line 15.
Zwischen der Steuerleitung 90 und dem Rückschlagventil 83 ist in die Druckleitung 15 eine Drossel 91 eingesetzt. In die Druckleitung 19 ist ebenfalls eine Drossel 92 eingesetzt, und zwar zwischen dem Rückschlagventil 84 und der Steuerleitung 89.A throttle 91 is inserted between the control line 90 and the check valve 83 in the pressure line 15. A throttle 92 is also inserted into the pressure line 19, namely between the check valve 84 and the control line 89.
Das Steuerventil 31 ist über die Steuerleitungen 29 und 33 mit den Druckleitungen 15 bzw. 19 verbunden, und zwar jeweils zwischen den zu den Rückschlagventilen führenden Steuerleitungen 90 bzw. 89 und dem Differentialzylinder 11.The control valve 31 is connected via the control lines 29 and 33 to the pressure lines 15 and 19, respectively between the control lines 90 and 89 leading to the check valves and the differential cylinder 11.
In der gezeichneten Stellung des Steuerventils 31 und der Rück¬ schlagventile 83, 84 können bei zunächst druckloser Stelleinrichtung und anlaufender Pumpe 17a beide Rückschlagventile 83, 84 öffnen. In den Druckleitungen 81, 82 und in den Druckleitungen 15 und 19 baut sich vor den Drosseln 91 und 92 ein bestimmter Druck auf, der auch in der Druckleitung 19 hinter der Drossel 92 herrscht. Aufgrund der Entlastung der Druckleitung 15 zum Behälter über das Steuerventil 31 kann sich hinter der Drossel 91 kein derartiger Druck aufbauen.In the illustrated position of the control valve 31 and the check valves 83, 84, both check valves 83, 84 can open when the actuating device is initially depressurized and the pump 17a starts. A certain pressure builds up in front of the throttles 91 and 92 in the pressure lines 81, 82 and in the pressure lines 15 and 19, which pressure also prevails in the pressure line 19 behind the throttle 92. Due to the relief of the pressure line 15 to the container via the control valve 31, no such pressure can build up behind the throttle 91.
Über die Steuerleitung 89 wirkt der in der Druckleitung 19 an¬ stehende Druck auch auf das Rückschlagventil 83, so daß aufgrund der zusätzlich wirkenden Kraft der Druckfeder 87 das Rückschlagventil 83 geschlossen wird. Durch den sich aufbauenden Druck im Druckraum 18 und aufgrund der Entlastung der Druckkammer 14 zum Behälter 35 wird der Differentialkolben nach links ("spät") bewegt.The pressure in the pressure line 19 also acts on the check valve 83 via the control line 89, so that the check valve 83 is closed due to the additional force of the compression spring 87. Due to the pressure building up in the pressure chamber 18 and due to the relief of the pressure chamber 14 to the container 35 the differential piston is moved to the left ("late").
Um eine Verstellung des Differentialkolbens nach rechts ("früh") zu erzeugen, wird das Steuerventil 31 durch entsprechende Erregung der Magnetspule in die zweite SchaltStellung bewegt, so daß die Druck¬ leitung 19 zum Behälter entlastet ist. Entsprechend zur zuvor be¬ schriebenen Schaltstellung wird dann das Rückschlagventil 84 in Schließstellung bewegt, so daß bei entlastetem Druckraum 18 und druckbelasteten Druckraum 14 eine Bewegung des Differentialkolbens nach rechts erfolgt.In order to produce an adjustment of the differential piston to the right ("early"), the control valve 31 is moved into the second switching position by appropriate excitation of the solenoid coil, so that the pressure line 19 to the container is relieved. In accordance with the switching position described above, the check valve 84 is then moved into the closed position, so that when the pressure chamber 18 and pressure chamber 14 are relieved of pressure, the differential piston moves to the right.
Die Haltestellung (stationäre Stellung des Differentialkolbens) kann entweder durch entsprechend getaktete Ansteuerung des Steuerventils oder über eine Druckregelung bei teilerregter Magnetspule realisiert werden. Um die Verlustleistung der hydraulischen Stelleinrichtung zu begrenzen, sollte der Druckabfall an den Drosseln 91 bzw. 92 auf beispielsweise 5 bis 10 bar begrenzt werden. The stop position (stationary position of the differential piston) can be achieved either by appropriately clocked control of the control valve or by pressure control with a partially excited solenoid. In order to limit the power loss of the hydraulic actuating device, the pressure drop at the throttles 91 and 92 should be limited to, for example, 5 to 10 bar.

Claims

Ansprüche Expectations
1. Hydraulische Stelleinrichtung (10) mit mindestens einer Hydraulikpumpe (17, 17a) und mit einem Differentialzylinder (11), in dessen Druckräumen (14 und 18) sich durch teilweises Abströmen von Druckmittel über ein elektromagnetisch betätigtes Steuerventil (31) jeweils ein Teildruck einstellt, der durch entsprechende Ansteuerung des Steuerventils stetig oder unstetig in Abhängigkeit bestimmter Kriterien veränderbar ist, wobei bei stationärer Stellung des •Differentialkolbens Haltedrücke eingestellt sind, die sehr viel kleiner sind als die Verstelldrücke, dadurch gekennzeichnet, daß jeder der Druckräume jeweils über eine Druckleitung (15, 81; 19, 82) mit der Pumpe verbunden ist, und daß zwischen die beiden Druck¬ leitungen (15, 19) das Steuerventil (31) geschaltet ist.1. Hydraulic actuating device (10) with at least one hydraulic pump (17, 17a) and with a differential cylinder (11), in the pressure chambers (14 and 18) of which partial pressure is set by partial discharge of pressure medium via an electromagnetically actuated control valve (31) that certain by corresponding activation of the control valve continuously or discontinuously in dependence criteria is changeable, wherein holding pressures are set at stationary position of the • differential piston, which are much smaller in than the adjustment pressures, characterized in that each of the pressure chambers in each case via a pressure line (15 , 81; 19, 82) is connected to the pump, and that the control valve (31) is connected between the two pressure lines (15, 19).
2. Hydraulische Stelleinrichtung nach Anspruch 1, dadurch gekenn¬ zeichnet, daß das Steuerventil (31) ein 3/2-Wegeventil in Sitzbau¬ weise ist.2. Hydraulic actuating device according to claim 1, characterized gekenn¬ characterized in that the control valve (31) is a 3/2-way valve in Sitzbau¬ way.
3. Hydraulische Stelleinrichtung nach Anspruch 1 oder 2, dadurch ge¬ kennzeichnet, daß das Steuerventil (31) mit einem Rücklauf (34) ver¬ bunden ist, und daß im Bereich der Führung des Ventilgliedes (59) im wesentlichen der im Rücklauf anstehende Druck vorherrscht. 3. Hydraulic actuating device according to claim 1 or 2, characterized ge indicates that the control valve (31) is connected to a return (34), and that in the region of the guide of the valve member (59) essentially the pressure present in the return prevails.
4. Hydraulische Stelleinrichtung nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß jede Druckleitung (15, 19) jeweils mit mindestens einem Druckraum (16, 20) der Pumpe (17) verbunden ist.4. Hydraulic actuating device according to one of claims 1 to 3, characterized in that each pressure line (15, 19) is each connected to at least one pressure chamber (16, 20) of the pump (17).
5. Hydraulische Stelleinrichtung nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß in jeder Druckleitung (15, 19) ein vom Druck in der anderen Leitung (19, 15) gesteuertes Sperrventil (83, 84) angeordnet ist.5. Hydraulic actuating device according to one of claims 1 to 3, characterized in that in each pressure line (15, 19) a check valve (83, 84) controlled by the pressure in the other line (19, 15) is arranged.
6. Hydraulische Stelleinrichtung nach Anspruch 5, dadurch gekenn¬ zeichnet, daß das Sperrventil (83, 84) ein Rückschlagventil ist, dessen Ventilglied (85, 86) von einer Druckfeder und dem Druck in einer Steuerleitung (89, 90) beaufschlagt ist.6. Hydraulic actuating device according to claim 5, characterized gekenn¬ characterized in that the check valve (83, 84) is a check valve, the valve member (85, 86) is acted upon by a compression spring and the pressure in a control line (89, 90).
7. Hydraulische Stelleinrichtung nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß in jeder Druckleitung (15, 81; 19, 82) eine Drossel (91, 92) angeordnet ist.7. Hydraulic actuating device according to one of claims 1 to 6, characterized in that a throttle (91, 92) is arranged in each pressure line (15, 81; 19, 82).
8. Hydraulische Stelleinrichtung nach Anspruch 7, dadurch gekenn¬ zeichnet, daß die Drossel (91, 92) zwischen dem Rückschlagventil (83, 84) und der das Rückschlagventil (84, 83) in der anderen Druck¬ leitung steuernden Steuerleitung (90, 89) angeordnet ist. 8. Hydraulic actuating device according to claim 7, characterized gekenn¬ characterized in that the throttle (91, 92) between the check valve (83, 84) and the check valve (84, 83) in the other Druck¬ line control line (90, 89th ) is arranged.
EP92918895A 1991-10-10 1992-09-04 Hydraulic control device Expired - Lifetime EP0609233B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4133526A DE4133526A1 (en) 1991-10-10 1991-10-10 HYDRAULIC ACTUATOR
DE4133526 1991-10-10
PCT/DE1992/000747 WO1993007362A1 (en) 1991-10-10 1992-09-04 Hydraulic control device

Publications (2)

Publication Number Publication Date
EP0609233A1 true EP0609233A1 (en) 1994-08-10
EP0609233B1 EP0609233B1 (en) 1995-12-06

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JP (1) JPH07500163A (en)
KR (1) KR100287308B1 (en)
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WO (1) WO1993007362A1 (en)

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DE19604865B4 (en) * 1996-02-10 2009-05-07 Schaeffler Kg Actuating cylinder of a camshaft adjuster which can be acted upon by a separate oil delivery device
NL1003536C2 (en) * 1996-07-08 1998-01-12 Applied Power Inc Control arrangement for double-action hydraulic cylinders
US6158404A (en) * 1997-02-26 2000-12-12 Aft Atlas Fahrzeugtechnik Gmbh Apparatus for regulating the operation of an adjusting device
DE19837693A1 (en) * 1997-08-21 1999-02-25 Schaeffler Waelzlager Ohg Timing control for IC engine
DE19840894B4 (en) * 1998-09-08 2006-07-27 Hydraulik-Ring Gmbh Hydraulic actuating device
CN103307060B (en) * 2013-06-18 2016-02-03 南京埃斯顿自动化股份有限公司 The oil hydraulic cylinder control system of directly driving type servo-pump control electricity liquid combination drive and controlling method

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EP0609233B1 (en) 1995-12-06
JPH07500163A (en) 1995-01-05
DE4133526A1 (en) 1993-04-15
US5476031A (en) 1995-12-19
WO1993007362A1 (en) 1993-04-15
KR100287308B1 (en) 2001-04-16
DE59204625D1 (en) 1996-01-18

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