WO2008000707A1

WO2008000707A1 - Method for actuating an electrohydraulic soft top, and system for carrying out said method

Info

Publication number: WO2008000707A1
Application number: PCT/EP2007/056284
Authority: WO
Inventors: Vincent Rieger; Matthias Mueller
Original assignee: Robert Bosch Gmbh
Priority date: 2006-06-26
Filing date: 2007-06-22
Publication date: 2008-01-03
Also published as: DE102006029216A1

Abstract

Disclosed is a method for actuating an electrohydraulic soft top (100) or a user-friendly drive unit in a motor vehicle, comprising at least one double-acting hydraulic cylinder (2) in which a hydraulic force can be applied to a piston (3) in a first control pressure chamber (6) that can be connected to a tank volume (24) via a first valve (15) or to a pressure medium source (19) via a second valve (16). A hydraulic force which counteracts the hydraulic force in the first control pressure chamber (6) can be applied to the piston (3) in a second control pressure chamber (8) that can be connected to the tank volume (24) via a third valve (17) and to the pressure medium source (19) via a fourth valve (18). The inventive method encompasses the following steps: the control pressure chamber (6, 8) that is to be filled is impinged upon by a specific volume flow from the pressure medium source (19) while the same specific volume flow is emptied from the control pressure chamber (8, 6) that is to be emptied into the tank volume (24) in order to displace the piston (3) during normal operation; the volume flow from the pressure medium source (19) into the first control pressure chamber (6, 8) and the volume flow from the control pressure chamber (8, 6) that is to be emptied into the tank volume (24) are decreased by triggering the valves (15 to 18) so as to reduce the displacement speed of the moved piston (3), especially until the piston (3) comes to a standstill.

Description

description

title

Method for operating an electro-hydraulic convertible top and system for carrying out the method

State of the art

The invention is based on a method for operating an electro-hydraulic convertible top or a comfort drive in a motor vehicle and an electro-hydraulic system for carrying out such a method according to the preamble of the independent claims.

DE 102 96 739 T5 has disclosed a hydraulic circuit with a return line metering valve, in which four proportional valves are connected to a double-acting cylinder. Two of the proportional valves are connected to a pressure medium source, the other two proportional valves are connected via a common return line via a return line metering valve to a tank. Various operating modes are described in which, in particular, the return line metering valve is modulated between the two proportional valves and the tank for controlling the pressure medium flows. However, no operating method is disclosed in which the piston can be selectively actively decelerated.

Disclosure of the invention

Advantages of the invention

The B etätigungs method according to the invention and the electro-hydraulic system for carrying out the method with the features of the independent claims have the advantage that are selectively controlled by the active loading of the signal pressure chamber to be emptied with a nem pressure from the pressure medium source of the braking process can. In this case, the valve which connects the control pressure chamber to be emptied with the pressure medium source, is opened, so that via this valve, a volume flow flows through the valve, which connects the control pressure chamber to be emptied with the volume tank. By deliberately closing the valve between the signal pressure chamber to be emptied and the volume tank, the braking behavior of the piston can be actively influenced.

The measures listed in the dependent claims advantageous refinements and improvements of the embodiments specified in the dependent claims are possible. If the valve suddenly closes between the signal pressure chamber to be emptied and the volume tank, suddenly there is a very high back pressure at the signal pressure chamber to be emptied, which abruptly slows down the piston. As a result, a very effective full braking can be realized.

In an alternative method, the valve between the pressure chamber to be emptied and the volume tank is not closed abruptly, but the valve is set to a predefinable flow position, so that the flow rate through this valve, the braking rate can be controlled.

In order to realize a gentle deceleration of the piston, in this case the volume flow through this valve can be closed after a desired passage of time. Thus, for example, initially a larger volume flow can be allowed through this valve and only after a certain time delay, the valve will be completely closed. As a result, excessive retardation of the part to be adjusted is avoided and a harmonious movement of the actuator can be achieved.

In a preferred embodiment, the predeterminable time profile for the flow control of the valve is designed as a rising ramp, which increases linearly, for example, until the valve is completely closed. By realizing an active targeted braking behavior of the piston, the piston can be operated in a rapid traverse in another operating function. For this purpose, the four control valves are switched such that the pressure medium is returned from the signal pressure chamber to be emptied again to be filled Stelldruckraum the cylinder. As a result, the pump has to pump less pressure medium, whereby the piston is adjusted much faster. In this operating state, the two valves that connect the control pressure chambers with the tank volume, closed, including, for example, the valves by means of appropriate Energization are brought out of their rest position. At the same time, the other two valves that connect the control pressure chambers with the pump, open, which is also realized for example by the active energization of the valves. By means of such an expressive function of the piston actuation, the electrohydraulic system can at the same time additionally provide a volume flow for an additional adjustment function.

To realize the actuation method according to the invention, it is particularly advantageous if in the electro-hydraulic system at least one double-acting hydraulic cylinder is actuated with four valves, wherein the valves which connect the control pressure chambers with the tank volume, are designed as proportional valves and the valves connect the control pressure chambers with the pressure medium source, are designed as simple switching valves. In such an arrangement, the active braking method can be realized particularly favorable, since the pressure at the signal pressure chamber to be emptied via the switching valve immediately fully applied and can be variably controlled via the corresponding proportional valve to the tank volume. Be for the four

Control valves used in each case 2/2-way valves, these can be arranged in a particularly compact and space saving a common compact valve block, whereby the piston can be operated very inexpensively.

For the inventive active braking method of the piston, it is advantageous if the first and third valve that connects the control pressure chambers with the tank volume, are closed in its rest position, and this is effected even in the de-energized state by elastic return elements. The second and fourth valves, which connect the control pressure chambers to the pressure medium source, are closed in their rest position, however, so that the piston can be adjusted in the event of a power failure in an emergency operation, for example manually. With such a design of the valve rest positions, the rapid traverse according to the invention can be realized by the simultaneous energizing of all four valves.

If the proportional valves are connected to an amplifier stage of the control unit, it is very easy to apply to the proportional valves a control signal which maps the time course of the braking operation. As a control variable for this purpose, the coil current can be used, which determines the actuating position of the valve via the electromagnet. If no further switching valves or proportional valves are arranged between the four control valves of the cylinder and the tank volume or the pressure medium source, a very effective and reliable hydraulic circuit for the actuating method according to the invention can be provided with a total of four 2/2-way valves. By eliminating further switching, throttling or metering valves, on the one hand, additional components are saved and, on the other hand, the efficiency of the circuit arrangement is thereby increased.

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. Show it

1 shows a hydraulic circuit diagram of an electro-hydraulic convertible top,

FIG. 2 schematically shows an active deceleration method according to the invention,

FIG. 3 schematically shows another active deceleration method according to the invention,

Figure 4 is a curve of a control signal to Figure 2 and Figure 3und

Figure 5 shows the scheme of a B etätigungs method according to the invention with high speed.

The illustrated in Fig. 1 hydraulic actuator 1 comprises a hydraulic cylinder 2, in which a piston 3 is arranged longitudinally displaceable. In order to transmit the movement of the piston 3 to an actuated flap or, for example, a hood 100 of a convertible, a piston rod 4 is fixedly connected to the piston 3.

The piston 3 has a first piston surface 5, which limits a first control pressure chamber 6 in the hydraulic cylinder 2. On the side facing away from the first piston surface 5, a second piston surface 7 is formed on the piston 3, which limits a corresponding second actuating pressure chamber 8 in the hydraulic cylinder 2. Depending on the force acting on the piston 3 resulting hydraulic force of the piston 3 is displaced in the hydraulic cylinder 2 in the axial direction. For generating the hydraulic force on the piston 3, the pressure in the first control pressure chamber 6 can be changed via a first control pressure line 9 and the pressure in the second control pressure chamber 8 can be changed via a second control pressure line 10. The first actuating pressure line 9 branches into a first line branch 11 and a second line branch 12. The second positioning pressure line 10 branches into a third line branch 13 and a fourth line branch 14. Via the first line branch 11, the first control pressure chamber 6 is connected to a first valve 15. Via the second line branch 12, the first control pressure chamber 6 is connected to a second valve 16. Accordingly, the second control pressure chamber 8 is connected via a third line branch 13 with a third valve 17 and via the fourth line branch 14 with a fourth valve 18. The first control pressure chamber 6 and the second control pressure chamber 8 are connected via the second valve 16 and the fourth valve 18 with a pressure medium source 19. In the embodiment shown, a hydraulic pump 19, which is preferably designed as a constant displacement pump, serves as the pressure medium source 19. The hydraulic pump 19 is provided for conveying in only one direction and is driven by an electric motor 20 which is connected to the hydraulic pump 19 via a shaft 21. The hydraulic pump 19 sucks pressure medium via a suction line 22 and a filter 23 arranged therein from a tank volume 24. The pressure fluid sucked in by the hydraulic pump 19 is conveyed by the hydraulic pump 19 into a working pressure line 25. The working pressure line 25 branches into a first working pressure line branch 26 and a second working pressure line branch 27. The first working pressure line branch 26 is connected to the second valve 16. The second working pressure line branch 27 is connected to the fourth valve 18. Via the second valve 16, a flow-through connection between the first working pressure line branch 26 and the second line branch 12 can be established, so that the pressure medium conveyed by the hydraulic pump 19 into the working pressure line 25 is conveyed via the first working pressure line branch 26, the second line branch 12 and the first Stelldruckleitung 9 flows into the first control pressure chamber 6 and there applied to the first piston surface 5 with a hydraulic force. Likewise, through the fourth valve 18, the second working pressure line branch 27 can be connected to the fourth line branch 14 in a flow-through manner. The pumped by the hydraulic pump 19 in the working pressure line 25 pressure fluid then flows through the second working pressure line branch 27, the fourth line branch 14 and the second actuating pressure line 10 in the second control pressure chamber 8. There, the second piston surface 7 is acted upon by a hydraulic force. In the embodiment shown in FIG. 1, the first piston surface 5 and the second piston surface 7 are of different sizes. If, therefore, the first piston surface 5 and the second piston surface 7 are both subjected to the pressure generated by the hydraulic pump 19, then the piston 3, together with the piston rod 4 in FIG. 1, moves to the right in the direction 64 and thus reduces the volume of the second control pressure chamber 8th. The first control pressure chamber 6 and the second control pressure chamber 8 are via the first valve 15 and the third valve 17 to the tank volume 24 towards relaxed. For this purpose, a flow-through connection can be produced by the first valve 15 from the first line branch 11 into the tank volume 24. Thus, with a corresponding switching position of the first valve 15, the first control pressure chamber 6 is connected via the first control pressure line 9 and the first

Line branch 11 relaxed in the tank volume 24. If the third valve 17 is in a corresponding setting position, then the third line branch 13 is connected to the tank volume 24 and the second setting pressure chamber 8 is expanded via the second setting pressure line 10 and the third line branch 13 into the tank volume 24.

The valves 15 to 18 are preferably 2/2-way valves, which are each held by a spring held in its rest position. The first valve 15 is held by a first spring 28 in a position in which there is a flow-through connection from the first leg 11 to the tank volume 24. In the opposite direction, the first valve 15 is acted upon by the force of an electromagnet 32, which brings the first valve 15 in a first switching position, in which the flow is blocked with appropriate energization. In this first switching position of the first valve 15, a relaxation of the first control pressure chamber 6 via the first line branch 11 into the tank volume 24 is thus not possible. If the first electromagnet 32 is not energized, the first spring 28 returns the first valve 15 to its second switching position, in which the first control pressure chamber 6 is expanded into the tank volume 24. Unlike the first valve 15, the second valve 16, which is arranged parallel to the first valve 15, acted upon by the force of a second spring 29 in the direction of the first switching position as a rest position. As long as a second electric magnet 32 acting in the opposite direction is not energized, no flow-through connection between the first working pressure line branch 26 and the second line branch 12 is produced. Only when the second electromagnet 33 is energized, the second valve 16 is actuated in the direction of its second switching position in the pressure medium from the first working pressure line branch 26 can flow into the second leg 12. In this second switching position of the second valve 16, pressure medium is conveyed by the hydraulic pump 19 into the first control pressure chamber 6. The third valve 17 corresponds in its construction to the first valve 15, wherein it is held by a third spring 30 in its second setting position, in which the second control pressure chamber 8 is relaxed in the direction of the tank volume 24. Contrary to the force of the third spring 30 also acts E an electromagnet 34, the third valve 17 with a force in the direction of the first Schaltstel- ment applied. Finally, the fourth valve 18 is acted upon by a fourth spring 31, which holds it in its rest position. The rest position of the fourth valve 18 is, as with the second valve 16, the first switching position of the valve in which the flow is blocked. Contrary to the force of the fourth spring 31, a fourth solenoid 35 is arranged on the fourth valve 18, which brings the fourth valve 18 into its second switching position with a corresponding applied signal. In the second switching position of the fourth valve 18, the second control pressure chamber 8 is depressed by the hydraulic pump 19.

In the selected embodiment, in which the first valve 15 and the third valve 17 are held in their second switching position (open) at rest and simultaneously held by the corresponding springs, the second valve 16 and the fourth valve 18 in its first switching position (closed) It is achieved that the pressure in the first control pressure chamber 6 and in the second control pressure chamber 8 corresponds to the pressure level of the tank volume 24. The hydraulic cylinder 2 is thus pressureless. However, it is also conceivable to choose the respective other switching position of the valves 15-18 as a rest position.

It is only important that the pairs of a control pressure chamber 6, 8 associated valves 15, 16 and 17, 18 each have different switching positions as rest position. Preferably, the switching positions of the first and second valves 15, 16 and the third and fourth valves 17, 18 match in pairs, so that the rest position of the first valve 15 of the rest position of the third valve 17 and the rest position of the second valve 16 of the rest position of fourth valve 18 corresponds. The four electromagnets 32-35 for actuating the valves 15-18 are controlled via an electrical line 36. The electrical line 36 may, for. B. be a part of a bus system over which the electromagnets 32-35 can be controlled individually and independently of each other. The electrical line 36 is connected to a control unit 37. About the

Controller 37, the switching positions of the electromagnets 32-35 are defined and accordingly supplied to each electromagnet 32-35 individually rated current. To z. B. to start the opening or closing operation of a convertible top of a convertible, the control unit 37 is transmitted by an operation switch 38, a corresponding start signal. In order to be able to recognize the end of a setting process, a signal line 39 is connected to an input of the control device 37, via which the control unit 37 is supplied with a voltage signal of a displacement meter 41. By the displacement sensor 41, the respective position of the piston rod 4 can be detected, so that for example towards the end of an adjusting movement, the speed of the electric motor 20 can be reduced. By a speed reduction of the electric motor 20 is of the Kon as Stantpumpe running hydraulic pump 19 promoted a smaller volume flow in the working pressure line 25. The adjusting movement slows down therefore. Via inputs / outputs 40, the control unit 37 communicates with other components of the vehicle. One of these outputs can z. B. control the speed of the electric motor 20.

In Fig. 1, the first valve 15 and the third valve 17 are formed as proportional valves, the forward current through the control unit 37 is variably adjustable. The rest position of the first and the third valve 15, 17 in this case represents an open, through-flow connection between the positioning space 6 and the tank volume 24, so that in an energized valve 15, 17, the control pressure chambers 6, 8 at the same pressure level with the tank volume 24 is located. The two valves 15, 17 are directly and directly connected to the tank volume 24, wherein in particular no further control valves between the valves 15, 17 and the tank volume 24 are arranged. The output 49 of the first and third valves 15, 17 is in each case directly connected to the tank volume 24 by a separate line 50, 51. The second valve 16 and the fourth valve 18 are each formed as switching valves having a locking state and a transmitting state. In this case, the blocking state is formed as a rest position, so that in case of power failure, the connection between the pressure medium source 19 and the control pressure chambers 6, 8 is interrupted. The arrangement with two proportional valves, which are each connected to the tank volume 24, and two

Switching valves which are connected to the pressure medium source 19 is particularly advantageous for 2/2-way valves 15 to 18 to produce, since in this case all four 2/2-way valves, or optionally further four units for additional piston 3 are low in a common valve block produced. Optionally, the hydraulic circuit has one or more pressure sensors 54, as shown in dashed lines in FIG. The pressure sensor

54 is arranged between the control pressure chamber 8 and the parallel-connected valves 17, 18 in the control pressure line 10. In this case, the pressure on the cylinder output side of the positioning space 8 is detected and a pressure signal 56 is forwarded to the evaluation unit 58. The evaluation unit 58 has a pressure regulator 60, by means of which a control signal 62 is generated with which the proportional valves 15, 17 are actuated. The

Evaluation unit 58 is integrated, for example, in the control unit 37. Information about the positions of the speed of the piston rod 4 can be obtained in the evaluation unit 58, whereby a control circuit can be created via the electrical control of the proportional valves 15, 17. If, for example, the piston rod 4 moves in the direction of the arrow 64 to the right, it is possible to move beyond the marked Neten pressure sensor 54, a control signal 62 for the proportional valve 17 are generated, which directly controls the adjustment of the piston rod 4 via the outlet velocity of the pressure medium from the control room 8 in the tank volume 24. In this case, the adjusting movement of the piston rod 4 is completely independent of the pressure medium source 19 applied power, or in the control pressure chamber 6 constructed pressure. In the same way, in the control pressure line 9 between the control pressure chamber 6 and the two valves 15, 16, a further pressure sensor 54 are installed to control the insertion movement of the piston rod 4 according to the proportional valve 15.

In a further, not shown variant of the hydraulic circuit is the second

Valve 16 and the fourth valve 18 as a proportional valve and the first valve 15 and the third valve 17 formed as a switching valve. Here, the adjustment of the piston rod 4 is not controlled by the outflow of the pressure medium from the control pressure chambers 6 and 8, as was the case in the circuit of Figure 1, but on the supply of the pressure fluid and the pressure medium source 19 via the proportional valves 16, 18 in the control pressure chambers 6, 8 inside. Here again, independently of the volume flow of the pressure medium source 19, the inflow of the pressure medium into the control pressure chamber 6 or 8 can be controlled via the variable flow control of the proportional valves 16 and 18, respectively.

It is obvious to the person skilled in the art that the described actuating device 1 is not limited to the application with only one hydraulic cylinder 2. Instead of one piston 3, a plurality of pistons 3 can be controlled in the circuits at the same time or several circuits for a plurality of pistons 3 can be built next to one another. Rather, an application together with a plurality of hydraulic cylinders 42 is possible. If the further hydraulic cylinders 42 are in each case in turn designed as double-acting hydraulic cylinders 42, each of the actuating pressure chambers thus created is assigned a pair of valves to the further hydraulic cylinders 42, as shown for the hydraulic cylinder 2 in FIG. The described circuits can be used particularly advantageously for the adjustment of the convertible top, in which the individual mutually movably arranged hood parts are each connected to a piston rod 4 in order to automatically adjust them. In a further application of the hydraulic circuit, it is possible, in particular, to adjust rotating or tilting parts on the motor vehicle, such as closures or flaps, by means of the comfort drive shown. FIG. 2 schematically shows the actuation method according to the invention with reference to the circuit according to FIG. 1 with the corresponding volume flows 83. The piston 3 is actively braked from its adjusting movement in the direction 64, in which the first control pressure chamber 6 is filled and the second control pressure chamber 8 is emptied. Here is the

Valve 16, which connects the pressure medium source 19 to the first control pressure chamber, closed, and designed as a switching valve 66 valve 18 which connects the pressure medium source 19 to the second control pressure chamber 8, opened. If now the valve 17 is closed, the pressure at the control pressure chamber 8 rises sharply, whereby the piston 3 is actively braked. According to the rest positions of the valves 15 - 18 are at

Braking operation only the valves 17 and 18 energized, as shown by a small flash 90 to the electromagnet 34, 35. The valve 17 is designed here as a proportional valve 68, so that the valve 17 can be closed by a predetermined curve 84. In this case, the setting position of the proportional valve 68 is actuated by a control signal 72, for example an exciter current for the electromagnet 34 of the valve 17. The control unit 37, for example, pressure and / or displacement signals of the sensors 41, 54, which can be used to generate the control signal 72.

FIG. 3 shows a further method for actively reducing the adjustment speed of the piston 3, in which, after the normal adjustment operation of the piston-for example in the adjustment direction 64-the first valve 15 is opened. As a result, pressure medium flows from the pressure medium source 19 via the open valve 16. A portion of the volume flow then flows directly back into the volume tank 24 via the at least partially opened valve 15. In this case, the volume flow which flows into the signal pressure chamber 6 to be filled decreases. The opening process of the valve 15 can be specified by a specific curve 84 in order to control the inflow into the control pressure chamber 6. At the same time, the valve 17, which connects the control pressure chamber 8 to be emptied with the volume tank 24, defined closed, so that via the valve 7, as in the embodiment of FIG. 2, the piston movement can be selectively braked. In this method, the speed reduction can be controlled in an adjustment direction 64 either by opening the valve 15 or by closing the valve 17 or by a combination of the two processes. Accordingly, of course, in a reverse adjustment (retraction of the piston 3 opposite Direction 64) of the piston 3 are actively decelerated by means of an exchanged control of the two valves 15, 16 with the valves 17, 18 active. It does not matter whether, in an adjustment of the piston in the direction 64 or in the opposite direction, on the piston, an external tensile force 95 or compressive force 96 acts. With the described methods, all movements of the adjustment process of the convertible

Roofs 100 are actively braked in both directions.

By way of example, FIG. 4 shows two curves 84, by means of which the valve 17, which connects the control pressure chamber 8 to be emptied with the tank volume, or the valve 15, which connects the control pressure chamber 6 to be filled with the tank volume, to the defined

Abbremsung the piston 3 can be controlled. On the Y-axis, the control signal 72 is shown, for example, a current or power signal for supplying electrical power to the coil of the electromagnet (34). In this case, a pulse-width-modulated PWM signal is preferably used as the control signal 72, which has a pulse ratio of 100%, for example, to close the valve 17 completely at a "closed position 73." At the first curve 85, the closing operation of the valve 17 begins at the starting point 87, wherein the adjustment position of the valve 17 is linearly adjusted until the valve 17 is completely closed at the end point 88. In an alternative adjustment curve 86, the valve 17 is first closed slowly and then ever faster, wherein the closing operation according to an arbitrary predetermined course 84 - for example according to a

Exponential Curve 86 - can be controlled. The curve 84 for the closing operation of the valve 17, for example, with respect to the time, against a pressure state of the system 1, or with respect to the path of the piston 3 or an adjustment angle of a top part 100 as X-axis 92 can be specified. Particularly easy is a fixed control signal waveform 84 relative to the time feasible.

In a further embodiment, the curve 84 is formed by a control loop, in which a sensor signal 41, 56 of the hydraulic system 1 is used as a controlled variable 91. As a sensor signal, in addition to the travel of the cylinder 3 and the pressure at a certain measuring point, a rotation angle of the kinematics of the convertible

Hood 100 can be used. Here, the curves 84 is not fixed unchangeable, but is determined by the controlled variable 91 during the adjustment process. The control or regulation according to the curve 84 can be used both for the opening of the valve 15 according to FIG. 3 and for the closing of the valve 17 according to FIG. 2 and 3 are applied in an adjustment direction 64. Conversely, the valves 17, 15 are driven in the opposite direction of adjustment of the piston 3.

5 shows a supplement to the actuating method according to the invention, in which an adjustment in the direction 64 in high-speed is shown before the targeted braking of the piston. For rapid adjustment of the piston 3, in addition to the "normal" filling of the first control pressure chamber 6 by the pressure source 19 via the valve 16, pressure medium is also conducted from the second control pressure chamber 8 into the control pressure chamber 6. For this purpose, the valve 17 is provided with the control pressure chamber 8 to be emptied the pressure medium tank 24 closes closed, which is realized in this case by energizing the electromagnet 34. On the other hand, the valve 18, which connects the control pressure chamber 8 to be emptied with the pressure medium source 19, opened, whereby the pressure medium to the pressure medium source 19 over directly is conducted into the valve 16, where it coincides with the pressure medium conveyed from the pressure medium source 19 and is passed through the valve 16 in the signal pressure chamber to be filled 6. As a result, the pump 19 - compared with the normal adjustment process - apply less flow, thus a High speed of the adjustment can be achieved and the targeted deceleration process illustrated in FIG. 2 and FIG. 3, such high-speed operation can be braked in a targeted manner without causing any damage due to an impact on a stop.

It should be noted that, with regard to the exemplary embodiments illustrated in the figures and the description, a variety of possible combinations of the individual features are possible with one another. For example, the number and arrangement of the pressure sensors 54 and the displacement sensors 41 can be varied to a corresponding control signal

72 to generate. On the other hand, an arbitrary curve 84 can be fixed, for example stored in the control unit 37. The actuation methods according to FIGS. 2 and 4 can be combined as well as applied individually. The hydraulic circuit 1 - in particular the use of switching or proportional valves 66, 68 can also be adapted to the specific operating method.

Claims

claims

1. A method for operating an electro-hydraulic convertible top (100) or a comfort drive in the motor vehicle, with at least one double-acting hydraulic cylinder (2), wherein in the at least one hydraulic cylinder (2) a piston (3) in a first control pressure chamber (6) a hydraulic force can be acted upon and the first control pressure chamber (6) via a first valve (15) with a tank volume (24) or via a second valve (16) with a pressure medium source (19) is connectable, and the piston (3) in one second control pressure chamber (8) can be acted upon by a hydraulic force which counteracts the hydraulic force in the first control pressure chamber (6), wherein the second control pressure chamber (8) via a third valve

(17) with the tank volume (24) and via a fourth valve (18) with the pressure medium source (19) is connectable, with the following method steps:

- For adjusting the piston (3) in a normal operation, the actuating pressure chamber to be filled (6, 8) with a certain volume flow from the pressure medium source (19) acted upon and the signal pressure chamber to be emptied (8, 6) with the same specific volume flow in the tank volume (24) emptied,

to reduce the adjustment speed of the moving piston (3), the volume flow from the pressure medium source (19) into the first control pressure chamber (6, 8) and the volume flow from the control pressure chamber (8, 6) to be emptied into the tank volume (24) reduced by means of a control of the valves (15-18), in particular until the piston (3) comes to a standstill.

2. The method according to claim 1, characterized by the following method steps:

- For adjusting the piston (3) in normal operation, the valve (16, 18) which connects the pressure medium source (19) to be filled with the signal pressure chamber (6, 8), and the valve (17, 15) to be emptied Signaling pressure chamber (8, 6) with the tank volume (24) connects, open, wherein the valve (18, 16), the pressure medium from the to be emptied signal pressure chamber (8, 6) passes, is closed - To reduce the displacement of the moving piston (3), the valve (15, 17), which connects the signal to be filled pressure chamber (6, 8) with the tank volume (24) is at least partially opened, whereby pressure medium from the pressure medium source (19 ) flows through the valve (16, 18) and via the valve (15, 17) into the tank volume (24)

- The valve (17, 15), which connects the pressure chamber to be emptied (8, 6) with the tank volume (24) is at least partially closed after a certain course, whereby the adjustment speed of the piston movement is reduced.

3. The method according to any one of claims 1 or 2, characterized in that for the targeted reduction of the piston movement, the valve (15, 17), which connects the signal pressure chamber to be filled (6, 8) with the tank volume (24), according to a predetermined curve (84) is opened.

4. The method according to claim 1, characterized by the following method steps:

- For adjusting the piston (3) in normal operation, the valve (16, 18) which connects the pressure medium source (19) to be filled with the signal pressure chamber (6, 8), and the valve (17, 15) to be emptied Set pressure chamber (8, 6) with the tank volume (24) connects, opened

- For active braking of the moving piston (3), the valve (16, 18), the pressure medium in the signal to be filled pressure chamber (6, 8) passes, closed

the valve (18, 16), which connects the corresponding control pressure chamber (8, 6) to be emptied to the pressure medium source (19), is opened, whereby pressure medium from the pressure medium source (19) via the valve (17, 15), which connects the control pressure chamber (8, 6) to be emptied with the tank volume (24), flows into the tank volume (24)

the valve (17, 15), which connects the control pressure chamber (8, 6) to be emptied to the tank volume (24), is at least partially closed after a certain course, as a result of which the pressure drop resulting from this valve (17, 15)

Counteracts piston movement for the purpose of its deceleration.

5. The method according to any one of the preceding claims, characterized in that the valve (17, 15), which connects the to be emptied signal pressure chamber (8, 6) with the tank volume (24) is completely closed as soon as possible.

6. The method according to any one of the preceding claims, characterized in that the valve (17, 15) is set variably to a selectable flow rate.

7. The method according to any one of the preceding claims, characterized in that for gentle deceleration of the piston (3), the valve (17, 15) after a predetermined curve (84) is closed.

8. The method according to any one of the preceding claims, characterized in that as a curve (84) a control signal (72) of a control unit (37) is used, the a continuous increase (85, 86) - in particular with a linearly rising ramp (85) - With respect to an x-axis (90).

9. The method according to any one of the preceding claims, characterized in that the curves course (84) is represented by a control circuit to which a sensor signal (56, 41) is supplied as a controlled variable, in particular a path angle, pressure, or time signal ,

10. The method according to any one of the preceding claims, characterized in that for a - in particular previous - high speed of the piston (3) all four valves (15 - 18) are energized simultaneously, whereby the first and third valve (15, 17) closed and the second and the fourth valve (16, 18) are opened, and the pressure medium from the control pressure chamber (8, 6) to be emptied via the fourth and the second valve (18, 16) flows directly into the control pressure chamber to be filled (6, 8) ,

11. Electrohydraulic system (1), in particular an electro-hydraulic convertible top (100), for carrying out the method according to one of the preceding claims, characterized in that the second and the fourth valve (16, 18) as switching valves (66) are formed , and the first and the third valve (15, 17) are designed as proportional valves (68) to control the speed of movement of the

To influence the piston (3), wherein the switching valves (66) by means of electromagnets (33, 35) are switchable between two switching positions and the proportional valves (68) by means of electromagnets (32, 34) via a proportional control range adjustable to a variable setting position are.

12. Electrohydraulic system (1) according to one of the preceding claims, characterized in that the at least two switching valves (66) and the at least two proportional valves (68) are designed as 2/2-way valves, which are arranged in particular in a common valve block.

13. Electrohydraulic system (1) according to one of the preceding claims, characterized in that the switching valves (66) and the proportional valves (68) in each case by an elastic return element (28, 29) are held in a rest position and the rest positions of the first valve ( 15) and the third valve (17) is designed as an open position and the rest positions of the second valve (16) and the fourth valve (18) are formed as a closed position.

14. Electrohydraulic system (1) according to any one of the preceding claims, characterized in that the proportional valves (68) are each connected to an amplifier stage of a control unit (37) having a pulse width modulated control signal - in particular a coil current or a coil power for the electromagnet (32 , 34) - for controlling the proportional valves (68) supplies.

15. Electrohydraulic system (1) according to one of the preceding claims, characterized in that the at least two switching valves (66) and the at least two

Proportional valves (68) without the interposition of other switching or proportional valves (control) on the one hand directly to one of the control pressure chambers (6, 8) and on the other hand directly to the pressure medium source (19) or the tank volume (24) are connected.