EP0803630B1 - Hydraulic operating device - Google Patents

Description

The invention relates to an arrangement for hydraulic actuation of a Cover flap on a vehicle, with at least one double-acting hydraulic working cylinder, on the one hand on the vehicle and on the other hand on the Cover flap can be hinged and its work spaces each have a check valve each with one side of a switchable pressure source in connection stand, the two check valves a mutual unlocking device have and the two workrooms parallel to the check valves are connected via a preload valve.

Such arrangements are known (see e.g. DE 43 34 843 A1) and enable, for example, the automatic actuation of vehicle doors, Bonnets, maintenance flaps or cover flaps of the trunk or a room accommodating a folding top. Through the mutually unlockable Check valves ensure that when you turn off or If the operating pressure fails, the cover flap in the respective position remains locked hydraulically to prevent uncontrolled movements and thus to eliminate associated dangers. The preload valve enables one controlled further movement of the cover flap in this state, for example by hand, such as an emergency closing against one of the preload valve allow predetermined force.

A disadvantage of the known arrangement mentioned of the type mentioned especially the fact that the described emergency operation only in context with a volume-balanced working cylinder is possible because it otherwise problems with the removal or supply of hydraulic medium to the piston or rod-side working space there. A simple shutdown of the excess volume ejected from the respective work area into the Tank would still be possible - but there are problems with it in an emergency unpressurized supply of hydraulic medium to the other work area, because for the application in vehicles uses very thin, flexible cables which, on the other hand, are also due to the crowded accommodation options are relatively long, so that the absorbing work area is at least partially filled with outgassing air. This then leads that after dropping the manually operated cover flap it is undefined can fall back and cause damage and injury.

The object of the present invention is to provide a known arrangement of the Improve the type described above so that the disadvantages described be avoided and that in particular in a simple and safe manner Emergency actuation of the cover flap also on the usual, on the piston and rod side different volumes of the working cylinders having working spaces becomes possible.

This task is performed in accordance with an arrangement of the type mentioned the invention in that between the piston-side working space and the associated unlockable check valve when a adjustable pressure levels to an emergency shutdown valve is switched on, which is above that on the side of the pressure source before the associated one Check valve prevailing pressure can be shut off hydraulically. At a Failure of the hydraulic working pressure is still an easy one and safe emergency operation of the cover flap, for example by hand possible. When the working cylinder is pulled out by hand, this becomes the rod side Working space volume in the larger piston-side working space pushed over, the missing differential volume in the piston side Work space in the form of outgassing air can be accepted, since this usually only makes up a few percent of the volume and that thus given possibility of slight movement of the cover flap against doesn't bother this little air cushion. With the working cylinder pushed in by hand the rod-side working space becomes larger in volume on the piston side Working space completely filled - the excess volume is at the first such emergency operation via the emergency valve in the tank deactivated. Subsequent further emergency operations are carried out in both Just a corresponding pushing between the work rooms take place, again the small difference set described above each missing or accepted on the piston side. It follows a very simple and safe option for an emergency operation trained working cylinder.

In a preferred embodiment of the invention it is provided that parallel to that when a preferably adjustable piston-side is exceeded Pressure levels in the direction of the preload valve opening on the rod-side work space Another check valve is arranged, which when pressurized opens towards the piston-side working space. So that can for example when the cover flap opens when the working cylinder extends can be achieved very easily so that emergency opening by hand is facilitated, since the opened further check valve an emergency actuation in the direction Extending piston rod bypassing the preload valve is practical enables unhindered. Depending on the setting of the opening pressure of the preload valve can the lid to be operated in different positions the effect of gravity are supported, the set pressure threshold however, it also has an indirect influence on those required for emergency operation Has closing force.

According to a further embodiment of the invention, can be between the bias valve and piston-side working space a parallel arrangement of throttle and additional opening towards the piston-side working space Check valve must be switched on. On the one hand, the retraction or Inserting the working cylinder, also and especially in the event of an emergency operation the throttle point of the parallel arrangement in addition to the one threshold specified bias valve are braked and on the other hand by the parallel additional check valve still a hydraulically practically unhindered Extension or extension of the working cylinder with emergency actuation be ensured.

In a particularly preferred further embodiment of the invention can be provided be that in the connection of the two workrooms, preferably between the two parallel arrangements of the bias valve and others Check valve on the one hand and throttle point and additional check valve on the other hand, a switchable seat valve is switched on. This seat valve enables in the closed position in normal operation a hydraulically completely separate control of the two work rooms - in In emergency operation, the seat valve is open, which means the options described emergency operation is unimpeded.

On the control side of the emergency valve, the Invention a preferably adjustable throttle point can be switched on, which influences the movement behavior of that described above Approved for the first time in the direction of retracting the working cylinder.

Finally, according to another preferred development of the invention be provided that in the connection between rod-side work space and associated unlockable check valve a preferably adjustable Throttle point is arranged, which in a simple manner hydraulic closing as a result of the pressure drop of the hydraulically unlockable check valve on the piston side.

The invention will be explained in more detail below with reference to the drawings explained. Fig. 1 shows a schematic arrangement according to the present Invention in a vehicle and FIGS. 2 to 6 show a partial schematic, hydraulic circuit diagram of an arrangement according to the invention in different functional states.

The arrangement shown in Fig. 1 for hydraulic actuation of a Cover flap 1 on a vehicle 2 has at least one double-acting hydraulic working cylinder 3 on the one hand on the vehicle 2 and on the other is hinged to the cover flap 1. The not shown here Working spaces of the working cylinder 3 are connected via lines 4, 5 a hydraulic unit 6 connected, which via a connecting line 7 with the electrical system of the vehicle 2 is connected.

Instead of the direct linkage of the working cylinder 3 on both sides, which of course correspondingly movable lines 4, 5 or a total with the power cylinder 3 movable hydraulic unit 6 may require the articulation of the working cylinder 3 on the vehicle and / or cover flap side also take place indirectly via levers or the like, the Working cylinder 3 can also be fixed relative to the vehicle 2 could.

2 to 6 is the combination of hydraulic unit 6 and over the lines 4, 5 connected cylinder 3 shown in more detail.

The two working spaces 8, 9 of the working cylinder 3 are on the Lines 4, 5 and a check valve arranged in the hydraulic unit 6 each 10, 11 each with one side of a switchable pressure source 12 (here formed from a pump and drive motor). The two check valves 10, 11 are connected via lines 13, 14 and mutually unblocked. The two working spaces 8, 9 are via a preload valve 15 connected in parallel to the check valves 10, 11. Between the piston side Working space 8 and associated unlockable check valve 10 is a case Exceeding an adjustable pressure level to the control tank 16 Emergency valve 17 turned on, via a line 18 and the pump side the pressure prevailing check valve 10 can be shut off hydraulically. Parallel to that when one, preferably adjustable, piston-side is exceeded Opening pressure levels towards the rod-side work space 9 Preload valve 15 is a check valve 19 is arranged, which with appropriate Pressurization in the direction of the piston chamber 8 opens. Is between the bias valve 15 and piston-side working space 8 further a parallel arrangement of throttle point 20 and in the direction of the piston Working space 8 opening check valve 21 switched on. In the Connection of the two working spaces 8, 9 is between the two parallel arrangements of preload valve 15 and check valve 19 on the one hand and throttling point 20 and kickback 21, on the other hand, an electrically switchable as needed Seat valve 22 switched on, with which the two working spaces 8, 9 can be completely separated. On the control side of the emergency valve 17 a preferably adjustable further throttle point 23 is switched on. Another throttle point 24, which is also preferably adjustable finally in the connection between rod-side work space 9 and associated unlockable check valve 11 arranged.

The connecting line 7 shown in FIG. 1, which in FIGS. 2 to 6 is not shown separately, controls the motor of the pump of the pressure source 12, the seat valve 22 and a shuttle valve 25 between the adjustable Pressure relief valves 26, 27 leading to the tank 16 lines. Furthermore, could, for example, limit switches or via this connecting line 7 other position controls signals to control units not shown or deliver the like.

In the following the function of the arrangement shown is based on the individual actuation phases as illustrated in FIGS. 2 to 6.

1. Fig. 2: Hydraulic opening; Working cylinder 3 extends

The motor of the pump of the pressure source 12 is energized, the pump is running and delivers pressure medium via the check valves 10 and 21 in the piston side Working space 8. The seat valve 22 is also energized, with what shown the connection to the rod-side work space 9 interrupted is. The emergency valve 17 is controlled via the line 18. The pressure in piston-side working space 8 can be up to the required value build up. The cover flap 1 (Fig. 1) opens hydraulically until it stops in Working cylinder 3. The volume of the rod-side working space 9 flows via the check valve 11 hydraulically controlled via line 14 and the shuttle valve 25 into the tank 16. Depending on the counterweight or counterforce on the cover flap 1, the hydraulics deliver the total on the pressure relief valve 26 adjustable force. The pump runs until the cover flap 1 is open and is then switched off. Furthermore, the seat valve 22 de-energized after the hydraulic opening, after which the cover flap 1 by the pressure adjustable on the emergency valve 17 in the open position is held.

2. Fig. 3: Hydraulic closing; Working cylinder 3 retracts

The closing process described below can, for example, in three Phases are divided - apart from that it is of course also possible the entire closing process in only one phase, for example as in Fig. 3 or the third phase described below to be dropped.

In the first phase, as can be seen in FIG. 3, the motor of the pump the pressure source 12 is energized, here now pressure medium via the check valve 11 and the throttle point 24 in the rod-side working space 9 is promoted. The seat valve 22 is in turn energized and closed. The Cover 1 closes with a force that can be set on the pressure relief valve 27. The seat valve 22 blocks the connection to the piston-side working space 8. Das from this outflowing volume flows because of the blocked setback 21 via the throttle point 20 and the check valve controlled via line 13 10 and the shuttle valve 25 into the tank 16. The choke point 24 causes the check valve 10 to open reliably of the improved pressure build-up. The closing force is set so that the cover flap 1 (Fig. 1) even when the associated Vehicle or other unfavorable conditions. On the on the other hand, the closing force cannot be higher than at the pressure relief valve 27 can be set, with which it can easily be realized that the cover flap 1 can also be stopped by hand if necessary.

In a second phase of hydraulic closing, the motor is the Pump of the pressure source 12 is still energized while the seat valve 22 is de-energized and is switched to continuity. This can be for security reasons are provided, as a result of stopping the cover flap 1 with essential less effort is possible. Since the pressure source 12 continues normally promotes, a largely even downward movement is maintained and the rod-side working space 9 is sufficiently refilled. For example due to an obstacle stopping the cover flap 1 flows the occurring pump volume flow through the check valve 11, the Check valve 19, the then open seat valve 22, which via the line 13 controlled check valve 10 and the shuttle valve 25 in the tank 16th from.

In a third phase, the motor can turn for safety reasons the pressure source 12 and the poppet valve 22 remain deenergized, which the Cover flap 1 according to FIG. 1 only by its own weight in the completely closed position drops. In the event of a stop, only that occurs Weight of the cover flap 1, with a possible risk of injury is turned off. The flowing volume flow from the piston side Working space 8 flows partly through the throttle point 20, which then opened seat valve 22 and the bias valve 15 in the rod-side Working space 9 and the other part through the biased emergency valve 17 and the throttling point 23 in the tank 16. By filling the rod side Workspace 9 are noises in the hydraulics in a subsequent Reopening the cover flap 1 prevented. The throttle point 20 brakes in The closing movement of the cover flap 1 as a function of the speed, which further reduces the risk of injury. The emergency valve 17 acts in counter this phase of the relatively strong counterforce of the cover flap 1. With the throttle point 23 can further fine-tune the closing speed the cover flap 1 are made.

3. Fig. 4: Stop function

The motor of the pump of the pressure source 12 is de-energized. The seat valve 22 is energized only briefly until the cover flap 1 brakes or comes to a standstill has come. Thereafter, the seat valve 22 is switched off, which in With regard to energy consumption e.g. a vehicle battery very advantageous is. This stop function can be in the range of the two described above first phases of closing take place at any time. The cover flap 1 will held by the pressure set on the emergency valve 17. In the case of FIG. 1 shown arrangement of the cover flap 1 is described in the above third phase of the alone by the weight of the cover 1 fully closed, no separate stop function is provided. This is not a disadvantage, however, since the cover flap 1 is described in this phase can also be easily stopped by hand.

4. Fig. 5: Emergency function - opening the cover flap 1 by hand, for example if the pressure source 12 fails due to a lack of power supply.

The cover flap 1 can be opened with relatively little effort become. There is only the weight of the cover flap 1 itself and to overcome the flow resistance in the hydraulics. Possibly in the vehicle built-in gas springs acting on the cover flap 1 also act supportive. As can be seen, the pressure medium flows from the rod side Working space 9 almost without pressure and therefore with little required Exertion of force via the check valve 19, the seat valve 22 and the Check valve 21 in the piston-side working space 8 and fills it up. This is extremely important so that the cover flap 1 after such Emergency operation also stops and does not hit against an air cushion this work space 8 can fall behind, which is a major security risk could represent. As a result of the vacuum when the piston side is not filled Working space would be released from the pressure medium. That on this Of course, when filling the piston-side working space there is no difference in volume due to the smaller volume of the rod-side work space 9 is only a few percent and is meaningless in terms of security.

5. Fig. 6: Emergency function - closing the cover flap 1 by hand

This is again necessary, for example, if the pump drive fails. As shown, the volume flow flows from the piston-side working area 8 via the throttle point 20, the seat valve 22 and the bias valve 15 in the rod-side work space 9 and fills it up. The choke point 20 has the function of closing speed too fast brake harder than at slow closing speed. The preload valve 15 acts as a support against the weight of the cover flap 1. At a The excess differential flow rate can be used for the first time of the working cylinder 3 flow out via the emergency valve 17, with yet to mention is that the pressure set at this emergency valve 17 is higher than the on the bias valve 15th

Apart from the arrangement and operation shown and described a cover flap 1 according to FIG. 1 (for example on a trunk or the hood of a car) could be the inventive arrangement of course also for the actuation of vertical in the closed state Tailgates can be used for example a station wagon or a bus. Other application examples would be e.g. Vehicle doors, maintenance or ventilation flaps and the like.

Claims (6)

1. An arrangement for the hydraulic operation of a hinged cover (1) on a vehicle (2) with at least one double-acting hydraulic power cylinder (3) with an articulated joint on the vehicle (2) on the one hand and on the hinged cover (1) on the other hand, and whose pressure chambers (8, 9) via one check valve each (10, 11) are joint to the respective sides of a switchable pressure source (12) whereby the two check valves (10, 11) have a reciprocal relief device and the two pressure chambers (8, 9) are connected in parallel to the check valves (10, 11) via a pressurising valve (15), characterised in that, between the pressure chamber (8) and the associated relievable check valve (10), an emergency valve (17) is placed into the circuit, which discharges to a tank (16) of the arrangement when an adjustable pressure level is exceeded and which can be shut off hydraulically via the pressure prevailing on the side of the pressure source (12) ahead of the associated check valve (10).
2. The arrangement according to claim 1, characterised in that, parallel to the pressurising valve (15) which opens towards the rod-side pressure chamber (9) in response to a preferably adjustable, piston-side pressure level being exceeded, a further check valve (19) is placed which under pressure opens towards the piston-side pressure chamber (8).
3. The arrangement according to claims 1 or 2, characterised in that, between the pressurising valve (15) and the piston-side pressure chamber (8), a parallel arrangement of throttle (20) and an additional check valve (21) is placed into the circuit, which opens towards the piston-side pressure chamber (8).
4. The arrangement according to one or more of claims 1 to 3, characterised in that into the connection of the two pressure chambers (8, 9), preferably between the two parallel arrangements of pressurising valve (15) and the further check valve (19) on the one hand and the throttle (20) and the additional check valve (21) on the other hand, a seat valve (22), switchable as required, is placed in the circuit.
5. The arrangement according to one or more of claims 1 to 4, characterised in that, in the discharge line of the emergency valve (17), a preferably adjustable throttle (23) is placed into the circuit.
6. The arrangement according to one or more of claims 1 to 5, characterised in that, into the connection between the rod-side pressure chamber (9) and the associated, relievable check valve (11), a preferably adjustable throttle (24) is placed into the circuit.

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