Car door drive

Abstract

The present invention relates to a drive device for a door (2) of a motor vehicle, comprising at least one gas pressure element (4), in particular a gas spring, having a cylinder (6) sealed towards the outside and a piston (8) running along a cylinder axis (A) in a cylinder interior (7) and dividing the cylinder interior (7) into two partial chambers (7a, 7b), the gas pressure element (4) having a first drive connection (4a) connected to the cylinder (6) and a second drive connection (4b) connected to the piston (8), the cylinder (6) being The drive device is filled with a fluid, in particular a fluid under pressure, and the piston (8) has an overflow passage device (9) that generates a compensating flow between the two partial chambers (7a, 7b) during piston movement in order to compensate for the pressure gradient between the two partial chambers (7a, 7b). The piston (8) is assigned a switchable valve device (10) that can be switched into different through-flow states, which differ in the cross-sectional size of the overflow passage device (9), depending on the pressure gradient between the two partial chambers (7a, 7b). It is proposed that the valve device (10) automatically switches into an overload state, which increases the cross-sectional size of the overflow passage device (9), when a predetermined upper limit value for the pressure gradient is exceeded.

Description

[Technical field]

[0001] The invention relates to a drive device for a door, in particular a tailgate, of a motor vehicle according to the preamble of claim 1, to a drive device for a door, in particular a tailgate, of a motor vehicle according to the preamble of claim 15 and to a door arrangement comprising a door, in particular a tailgate, and such a drive device according to claim 16.

[0002] The drive device in question is used in the field of motorized actuation of any door-like object in a motor vehicle. Such a door can be, for example, a tailgate, a rear lid, an engine hood, a luggage compartment floor, but can also be a door of a motor vehicle. In this respect, the term "door" is to be understood in a broad sense here.

[0003] The known drive (DE 10 2018 122 135 A1) from which the invention takes its starting point is used for motorized actuation of the tailgate of a motor vehicle. The drive comprises a motorized drive in the form of a spindle drive on one side of the tailgate, which has an electric drive unit and a spindle-spindle nut transmission connected downstream of the electric drive unit in terms of drive technology, by means of which a linear drive movement between the drive connection on the body side and the drive connection on the door side is generated for opening and closing the door. In the open position of the door, the spindle drive is in an extended position, whereas in the closed position of the door the spindle drive is in a retracted position.

[0004] Since the forces due to the weight of the tailgate can be considerable, it is advisable to arrange a gas pressure element in the form of a gas spring on the other side of the door apart from the spindle drive, which compensates for the forces due to the weight of the tailgate. This should usually be achieved so that the tailgate is always close to an equilibrium state or is pushed in the opening direction. Such a door arrangement with a motorized drive on one side of the door and a gas pressure element, here a gas spring, on the other side is also called an active / passive system.

[0005] The pneumatic element of the known drive is advantageous in that, via the switchable valve device, if there is no drive and / or retaining force of the drive, and thus the door is pushed in the closing direction due to the spring force and / or due to gravity, the valve device switches to a closed state which opposes further movement of the door, in particular prevents further movement of the door. The switching to the closed state is carried out as a function of the pressure, i.e. as a function of the pressure gradient between the two partial chambers in the pneumatic element, which in turn depends on the piston speed, i.e. the speed of the piston relative to the cylinder of the pneumatic element. In the case of high forces applied and the resulting high piston speeds and locking of the pneumatic element, however, the pressure in one of the two partial chambers bounded by the piston of the pneumatic element may exceed a critical pressure, which may lead to damage to the pneumatic element.

[0006] The object of the present invention is to design and develop the known drive in such a way that damage to the gas pressure element is prevented as far as possible.

[0007] The above object is achieved by the drive device according to the generic part of claim 1, by the features of the characterizing part of claim 1.

[0008] Firstly, a gas pressure element here means, quite generally, an element having a cylinder and a piston guided in the cylinder coaxially with respect to the cylinder axis, which provides pneumatic and / or hydraulic pressure, in particular hydrostatic and / or dynamic pressure, between the cylinder and the piston of the gas pressure element, in a state of rest and / or movement of the piston relative to the cylinder. The cylinder is filled in this case with at least one fluid, in particular a gas and / or a liquid, which can be filled in the cylinder under pressure, i.e. with a pressure above or below the ambient pressure, or without pressure, i.e. with a pressure that corresponds substantially to the ambient pressure. Preferably, the gas pressure element is formed exclusively by a gas spring, in particular a compression gas spring or a traction gas spring, i.e. a cylinder-piston arrangement in which the piston is filled with a fluid under pressure, in particular a positive pressure. The gas pressure element can also be formed by a gas damper, i.e. a cylinder-piston arrangement in which the piston is filled with a fluid without pressure. The gas pressure element may have as one component such a cylinder-piston arrangement, in particular a gas spring and / or a gas damper, and may additionally have as a further component a drive spring arrangement acting parallel or coaxially to the cylinder axis and thus to the direction of action of the gas pressure element or the gas spring or gas damper. In this respect, the terms "gas pressure element", "gas spring" and "gas damper" are therefore to be understood in the broad sense.

[0009] During normal operation, the gas spring or gas damper of the gas pressure element provided according to the present proposal functions in a manner that is typical per se like a conventional gas spring or conventional gas damper, which has a cylinder filled with a fluid, in particular filled with gas and / or liquid, and a piston guided in the cylinder. The gas pressure element thus utilizes the compressibility of the filled fluid, in particular gas, for its springing or damping action. In the case of a gas spring, when no force is introduced, the fluid under pressure presses against the cross-sectional area of ​​the piston, thereby driving the cylinder-side drive connection and the piston-side drive connection, which respectively connect the gas spring to the vehicle, away from each other. When a certain minimum compressive force is introduced from the outside via the drive connection into the gas spring, for example by operating the tailgate manually or via a motorized drive, both drive connections are driven towards each other. In the case of gas dampers, i.e. gas dampers whose fluid is pressureless when no force is introduced, the drive connections are only movable relative to one another by a compressive or tensile force introduced via the drive connections from the outside, e.g. caused by operation via a manual or motorized drive of the tailgate, whereby the fluid is subjected to pressure via the cross-sectional area of ​​the piston.

[0010] The piston, in particular the base body of the piston, also referred to as the piston head, in both the gas spring and the gas damper, divides the cylinder interior into two partial chambers, and in particular the overflow channel arrangement, which is at least partially formed by the base body, enables the fluid to flow from one partial chamber into the respective other partial chamber in order to compensate for the pressure gradient between the partial chambers. The corresponding flow is referred to below as the compensating flow.

[0011] Thus, when a relatively large force is introduced into the gas pressure element, for example when the drive and / or holding force of the drive is absent and the door is pushed in the closing direction due to the spring force and / or due to gravity, or when the user closes the door manually, the piston speed may increase. It may then occur that the compensating flow cannot flow from one partial chamber to the other partial chamber quickly enough through the previous cross section of the overflow channel arrangement, since the cross section is too small for this. As a result, the pressure then increases in one of the partial chambers and thus the pressure gradient between the two partial chambers increases.

[0012] The important point is thus the basic idea that before a critical pressure is generated in one of the partial chambers, the switchable valve device automatically switches, depending on the pressure gradient between the two partial chambers, to a state which allows a particularly rapid pressure compensation between the partial chamber with the higher pressure and the partial chamber on the other side of the piston. This state in which the valve device switches is referred to below as the overload state. This means that, even if high forces are introduced into the gas pressure element, which in turn results in high piston speeds, the gas pressure element can thus be optimally protected against damage or even destruction.

[0013] During normal operation of the gas pressure element, as will be explained further below, pressure compensation is also performed between the two partial chambers separated by the piston in the gas pressure element. The compensating flow between the two partial chambers, which generates the pressure compensation, is not as large in this case as in the overload state. Furthermore, the valve device can be switched into a state in which the compensating flow is reduced, as will be explained further below, particularly if the pressure in one of the partial chambers increases to a certain level. This state is referred to below as the constriction state. If the pressure in this partial chamber increases further as a result, the valve device then switches into the above-mentioned overload state. It should be emphasized that the switching process is performed here automatically, i.e. without user intervention, and solely due to the pressure gradient between the two partial chambers, or in any case with the pressure gradient between the two partial chambers playing a decisive role. The pressure gradient is, on the other hand, dependent on the piston speed.

[0014] In particular, it is proposed that the valve device automatically switches over to an overload state when a predefined upper limit value for the pressure gradient is exceeded, which causes the cross section of the overflow passage device to be enlarged, in particular maximized.

[0015] Claim 2 provides for the possibility of switching to the narrowed state already mentioned above, in which case the cross section of the overflow channel arrangement is reduced, in particular minimized.

[0016] Claim 3 defines preferred piston speeds at which the valve arrangement switches to the constricted and overloaded states.

[0017] Claim 4 relates to an open state of the valve device, which the valve device occupies during normal operation of the gas pressure element, but also in the stationary state of the gas pressure element, from which the valve device switches first to a constricted state when the pressure gradient increases due to an increasing piston speed, and then further to an overloaded state when the pressure gradient increases still further due to a still increasing piston speed.

[0018] Claim 5, on the other hand, defines how the valve device preferably behaves when the pressure gradient drops again, so that the valve device then switches from the overloaded state to the constricted state and / or from the constricted state to the open state.

[0019] Claim 6 relates to a drive spring device for driving drive connections of a gas pressure element, which are preferably attached to the door on the one hand and to the vehicle body on the other hand, away from each other. The drive spring device may in this case have a coil spring, in particular in the cylinder of the gas pressure element, which as a pop-up spring opposes the piston movement in the cylinder only over a part of the movement of the piston and facilitates the opening of the door from the closed position.

[0020] Claim 7 provides that the valve device preferably reduces, in particular rapidly reduces, the pressure gradient in an overload state and can then automatically switch to the constriction state, thereby preventing people from being trapped when the door is suddenly closed. The drive spring device has a spring force that increases with the reduction in the distance between the two drive connections, so that a moment is generated via the spring force, which opposes the closing movement of the door and thereby additionally brakes the door (claim 8). Preferably, this occurs in such a way that the reduction in the shortest vertical distance between the pivot axis of the door and the line of action of the spring force during the closing movement of the door is at least partially compensated.

[0021] Claims 9 and 10 relate to the basic structure of the valve device and in particular define a valve body which is movable relative to the base of the piston in response to the pressure gradient and the piston speed.

[0022] Particularly preferred configurations of the overflow passage arrangement, in particular of the valve body and the base body, are the subject of claims 11 to 13.

[0023] According to an equally preferred configuration as claimed in claim 14, the valve body is biased by a force, in particular via a valve spring device, against the base body in any case in at least one of its constricted and overload positions, preferably towards at least one of its open positions.

[0024] According to a further idea of ​​the independent claim 15, a drive for a door, in particular a tailgate, of a motor vehicle is claimed, which has at least one gas pressure element, in particular a gas spring, which has a cylinder sealed towards the outside and a piston running in the cylinder interior along the cylinder axis and dividing the cylinder interior into two partial chambers, the gas pressure element has a first drive connection connected to the cylinder and a second drive connection connected to the piston, the cylinder is filled with a fluid, in particular a fluid under pressure, the piston has an overflow conduit arrangement by means of which a compensating flow between the two partial chambers is generated in relation to the piston movement in order to compensate for the pressure gradient between the two partial chambers, and a switchable valve arrangement is assigned to the piston, which valve arrangement can be switched into different through-flow states, which differ in terms of the cross-sectional size of the overflow conduit arrangement, depending on the pressure gradient between the two partial chambers. See the full description of the drive according to the proposal according to the first idea.

[0025] It is important that in this case the valve device automatically switches from the open state to a narrowing state, in which the cross section of the overflow channel arrangement is reduced relative to the open state, when a predefined lower limit value for the pressure gradient is exceeded, and automatically switches from the narrowing state to a closed state, in which the cross section of the overflow channel arrangement is reduced relative to the narrowing state, when a predefined upper limit value for the pressure gradient is exceeded. Starting from the open state, the cross section is first reduced in the narrowing state, as in the first concept, and then, however, unlike in the first concept, is reduced still further in the closed state.

[0026] According to a further idea, which is also independent of claim 16, a door arrangement per se is claimed, which comprises a door, in particular a tailgate, and a drive device according to the proposal assigned to the door. Reference is made to the full description of the drive device according to the proposed invention according to the first idea and the drive device according to the proposed invention according to the second idea.

[0027] The door can then preferably be pivoted about a pivot axis which is oriented approximately horizontally in the assembled state. The gas pressure element particularly preferably pre-biases the door, in particular in the direction of opening the door. In particular, the door device comprises a drive, in particular a linear drive, preferably a spindle drive, on a first side of the door and a gas pressure element on the opposite side. The drive is thus in particular an active / passive system.

[0028] The invention will now be explained in more detail with reference to the drawings, which show only one embodiment. [Brief description of the drawings]

[0029] [Figure 1] 1 shows the rear area of ​​a motor vehicle having a door device according to the proposal equipped with a drive device according to the proposal; [Diagram 2] 2A) and B) are cross-sectional views of the gas pressure element of the drive device shown in FIG. 1 in a stationary state, after the drive connections have been driven closer to each other in their end positions, and after the drive connections have been driven away from each other in their end positions. [Diagram 3] 2A to 2C are enlarged cross-sectional views of the valve device of the gas pressure element shown in FIG. 1, in which a) is in an open state, b) is in a constricted state, and c) is in an overloaded state. [Figure 4] 2A to 2C are enlarged cross-sectional views of the valve device of the gas pressure element shown in FIG. 1, where a) is a view of a first variant, b) is a view of a second variant, and c) is a view of a third variant.

[0030] The proposed drive 1 is here and preferably used for motorized actuation of a motor vehicle door 2. The proposed drive 1 may, in an alternative embodiment, however, be purely spring-driven, with at least one gas spring, or purely manually operable, with at least one gas damper. The door 2 can be actuated by the drive 1 in the opening direction and / or in the closing direction of the door 2.

[0031] The door 2 here and preferably is a tailgate of a motor vehicle. The proposed drive 1 can be used particularly advantageously precisely in the "tailgate" application, since the tailgate has a relatively high weight.

[0032] Basically, the proposed drive 1 also applies, however, to other types of doors 2 of motor vehicles, such as rear lids, front hoods, etc., but also doors. All statements apply correspondingly to other doors.

[0033] As shown in Fig. 1, the proposed drive 1 here and preferably comprises one, here exactly one, motorized drive 3. The motorized drive 3, which will be explained in more detail below, here and preferably is a linear drive, in particular a spindle drive.

[0034] Furthermore, the proposed drive 1 comprises one, here exactly one, gas pressure element 4. The gas pressure element 4 is here and preferably a gas spring, in particular a compression gas spring. Here and preferably the gas spring preloads the door 2 in the opening direction of the door 2. The gas spring can in principle also be a traction gas spring. It is also possible for the gas pressure element 4 to be a gas damper, i.e. not to have a spring action.

[0035] In the embodiment described here, and by way of example only, a gas spring is provided as gas pressure element 4. The comments in this regard, however, apply equally to the other gas pressure elements 4 mentioned.

[0036] The drive device 1 according to the proposal can in principle also have more than one motorized drive and / or more than one gas pressure element 4. In the case of the door device 5 shown in FIG. 1 which, besides the vehicle door 2, also has a drive device 1, the motorized drive 3 is arranged on a first side of the door 2 and the gas pressure element 4, or here a gas spring, is arranged on a second, opposite side of the door 2.

[0037] The motorized drive 3, which here forms the active side of the active / passive system, is provided for opening and closing the door 2. For this purpose, the drive 3 has a drive unit, not shown here, with an electric drive motor and possibly one or more further drive components, for example an intermediate transmission, an overload clutch and / or a brake. A linear transmission, in particular a spindle-spindle nut transmission, also not shown, is connected downstream in drive technology to the drive unit, which has as drive technology components, in particular a spindle and a spindle nut in meshing engagement with the spindle. Here and preferably, the spindle is drive technology connected to the drive unit and is rotated during operation, so that the spindle nut performs a linear movement along the spindle.

[0038] The motorized drive 3 with a drive unit and a linear transmission, in particular a spindle-spindle nut transmission, has a first, in particular a spindle-side, drive connection 3a and a second, in particular a spindle-nut-side, drive connection 3b, via which the drive 3 is connected to the motor vehicle. Here, and preferably, the drive 3 is connected to the door 2 via the spindle-side drive connection 3a and to the body of the motor vehicle via the spindle-nut-side drive connection 3b. The linear drive movement of the linear transmission drives the drive connections 3a, 3b away from each other (which corresponds to an operating movement of the door 2 in the opening direction of the door 2) or drives the drive connections 3a, 3b towards each other (which corresponds to an operating movement of the door 2 in the closing direction of the door 2).

[0039] The gas spring forming the passive side of the active / passive system, and here and preferably forming the gas pressure element 4, does not have its own motorized drive and here provides a spring function, and thus takes up part of the force due to the weight of the door 2, preferably thereby keeping the door 2 close to an equilibrium state when the door 2 is open, or pushing the door 2 in the opening direction.

[0040] The gas pressure element 4, in a manner typical per se, comprises a cylinder 6, which is sealed towards the outside, and a piston 8, which runs along the cylinder axis A in an inner chamber 7 radially surrounded by the cylinder 6 and divides the cylinder inner chamber 7 into two partial chambers 7a, 7b. The piston 8 comprises a piston rod 8a, which extends along the cylinder axis A and is movable relative to the cylinder 6. The piston rod 8a passes sealingly through an axial opening in the cylinder 6, so that one section of the piston rod 8a is arranged in the cylinder inner chamber 7 and another section is arranged outside the cylinder 6. The piston 8 further comprises a base body 8b on the section of the piston rod 8a which is arranged in the cylinder inner chamber 7, in particular at the front end of the piston rod 8a, which base body 8b in particular forms a piston head. The base body 8b here and preferably has a cross section with respect to a radial section of the cylinder 6, the cross section of the base body 8b corresponding to the cross section of the cylinder inner chamber 7.

[0041] The gas pressure element 4 further comprises a first drive connection 4a, which is connected to a cylinder 6, and a second drive connection 4b, which is connected to a piston 8. The cylinder 6 is then filled with a fluid under pressure, such that the two drive connections 4a, 4b are driven away from one another. The fluid is in particular a compressible gas, and may optionally also contain, preferably in small amounts, a liquid, for example oil, by which end position damping can for example be caused.

[0042] In the unloaded state, i.e. when no forces are acting from the outside on the gas pressure element 4, the two drive connections 4a, 4b are thus in the position maximally driven away from one another, which position is shown in Figs. 1 and 2b). This position of the drive connections 4a, 4b relative to one another here and preferably also corresponds to the open position of the door 2 shown in Fig. 1. The drive connection 4a on the cylinder side is then connected to the door 2, the drive connection 4b on the piston side is connected to the body of the motor vehicle. It should be emphasized again that, as mentioned above, the cylinder 6 may also be pressure-free, i.e. in case of a gas damper instead of a gas spring.

[0043] The piston 8 has an overflow passage arrangement 9 by means of which a compensating flow occurs between the two partial chambers 7a, 7b in order to compensate for the pressure gradient between the two partial chambers 7a, 7b as the piston moves.

[0044] In normal operation, therefore, the following occurs: In the event of an external force driving the drive connections 4a, 4b towards one another, for example when the door 2 is closed motorized or manually, the piston 8 is displaced relative to the cylinder 6 from the position shown in FIG. 2b), in particular towards the position shown in FIG. 2a). The section of the piston 8 which is arranged in the cylinder interior 7, i.e. along the cylinder axis A, moves through the cylinder interior 7, so that the two partial chambers 7a, 7b of the cylinder interior 7 change their volume. As can be seen in FIG. 2, in this embodiment, when the drive connections 4a, 4b are driven towards one another, the volume of the partial chamber 7a decreases, whereas the volume of the partial chamber 7b increases. In this case, as shown in the detailed view in FIG. 3a), the fluid flows as a compensating flow from the upper partial chamber 7a into the lower partial chamber 7b through the overflow channel arrangement 9. The fluid is filled in the cylinder 6, here and preferably under pressure, so that it presses against the cross-sectional area of ​​the piston 8, here the base body 8b, and thus always presses the piston 8 relative to the cylinder 6 towards the position shown in FIG. 2b). This is because the cross-sectional area of ​​the piston 8 or base body 8b on the side facing away from the piston, i.e. towards the partial chamber 7a, is larger than on the opposite side, since on the opposite side the cross-sectional area on which the fluid pressure is exerted is only formed by the ring extending around the piston rod 8a. The ring surface effective on the side of the partial chamber 7b is smaller than the surface effective on the side of the partial chamber 7a, which corresponds to the total cross-sectional area of ​​the cylinder interior 7. Correspondingly, a greater pressing force acts on the piston 8 or base body 8b from the side of the partial chamber 7a than from the other side, so that the piston 8 is always pushed out of the cylinder 6.

[0045] The piston 8 is thus assigned a switchable valve device 10, which can be put into different through-flow states, which differ in the size of the cross section of the overflow channel arrangement 9, depending on the pressure gradient between the two partial chambers 7a, 7b. By the cross section of the overflow channel arrangement 9 is meant the cross section through which a flow can flow during pressure compensation, providing a compensation flow. In this case, the following occurs: The pressure gradient changes depending on the piston speed v, i.e. the speed with which the piston 8 is moved relative to the cylinder 6, when the two drive connections 4a, 4b are driven towards each other. As the piston speed v increases, the compensation flow can no longer compensate the pressure gradient between the two partial chambers 7a, 7b fast enough, so that the pressure in one of the partial chambers, here the partial chamber 7a, increases more and more. The pressure acting on the base body 8b and the valve device 10 increases accordingly, which leads to the valve device 10 switching over to another through-flow state. This is explained in more detail below.

[0046] What is important, therefore, in particular when the two drive connections 4a, 4b are driven closer to one another, is that the valve device 10 automatically switches into an overload state in which the cross section of the overflow passage device 9 is enlarged, in particular maximized, when a predefined upper limit value for the pressure gradient is exceeded.

[0047] The cross-section (meaning the cross-sectional area perpendicular to the flow direction of the compensation flow) of the overflow channel arrangement 9 is defined as follows: if the overflow channel arrangement 9 has a plurality of fluid channels 11 which serve for the fluid-technical connection between the two partial chambers 7a, 7b, i.e. for conducting the compensation flow, then the cross-section of the overflow channel arrangement 9 corresponds to the sum of all the narrowest cross-sections of these fluid channels 11, i.e. the total cross-section resulting from the sum of all the individual cross-sections of these fluid channels 11 at their respective narrowest points. If the overflow channel arrangement 9 has only one such fluid channel 11, then the cross-section of the overflow channel arrangement 9 corresponds to the cross-section of this fluid channel 11 at its respective narrowest point.

[0048] By the valve device 10, the cross section of the overflow passage arrangement 9 is enlarged, it is meant that the cross section of the overflow passage arrangement 9 is in this case larger than it was last in the previous through-flow state, i.e. in the narrowed state which will be explained further below. By "maximize", it is meant that not only is the cross section of the overflow passage arrangement 9 in this case enlarged, but also that the maximum cross section that the overflow passage arrangement 9 can provide is achieved by the sum of all its narrowest cross sections.

[0049] The valve device 10 functions in this case in the form of an overpressure valve. If the pressure becomes too great in the partial chamber 7a, in particular as a result of a high piston speed v, i.e. if a predefined upper limit value for the pressure gradient is exceeded, the valve device 10 opens and allows a pressure compensation, in particular a rapid pressure compensation, between the partial chambers 7a and 7b. By means of such a pressure compensation, damage to the gas pressure element 4 is avoided when suddenly, in the case of an overload, very large forces drive the two drive connections 4a, 4b closer to each other faster and faster, so that the piston speed v increases.

[0050] The aforementioned function of being able to switch the valve arrangement 10 into an overload state is shown in Fig. 3c). Fig. 3a) shows the open state of the valve arrangement 10, which will be explained in more detail below, which the valve arrangement 10 occupies during normal operation of the gas pressure element 4. Fig. 3b) shows a state of the valve arrangement 10 between the open state and the overload state, the so-called constricted state, which will also be explained below.

[0051] Thus, here and preferably, the valve device 10 automatically switches to the aforementioned narrowing state when a predefined lower limit value for the pressure gradient is exceeded, in particular when the two drive connections 4a, 4b are driven towards one another, in which the valve device 10 reduces, in particular minimizes, the cross section of the overflow channel arrangement 9 in the narrowing state. Here and preferably, the cross section of the overflow channel arrangement 9 continues to remain open, but with a smaller cross section, after the predefined lower limit value for the pressure gradient is exceeded, until the predefined upper limit value for the pressure gradient is reached, i.e. in the narrowing state. As a result, the overflow channel arrangement 9 continues to remain passable. In principle, according to a further embodiment not shown here, it is also possible, however, for the cross section of the overflow channel arrangement 9 to be closed and thus no longer passable. The narrowing state is not necessarily a through-flow state, i.e. a through-flow state in which the cross section is only reduced compared to the previous through-flow state, but the cross section can also be completely closed. The valve device 10 then remains in this constricted state until an overload case occurs due to the further increasing piston speed v and the resulting further increasing pressure gradient, i.e. until the valve device 10 switches into the overload state, or until the gas pressure element 4 again switches to normal operation, for example, due to the disappearance of additional forces acting on the door 2, particularly during the closing process, resulting in a smaller piston speed v and therefore a correspondingly smaller pressure gradient.

[0052] By the valve device 10 reducing the cross-section of the overflow passage arrangement 9, it is meant that the cross-section of the overflow passage arrangement 9 is in this case smaller than when it was last in its previous through-flow state, i.e. in the open state, which will be explained further below. By "minimizing" it is meant that not only is the cross-section of the overflow passage arrangement 9 in this case smaller, but also that the minimum cross-section that the overflow passage arrangement 9 can offer by the sum of all its narrowest cross-sections is reached. As suggested, the minimum cross-section may also mean that the overflow passage arrangement 9 is in this case closed and cannot be passed through.

[0053] Exceeding a predefined lower limit value means here that the pressure gradient increases more and more until the predefined lower limit value is reached, but does not yet result in switching of the valve device 10. Only when the lower limit value is exceeded does the valve device 10 automatically switch, thereby reducing the cross section of the overflow channel arrangement 9.

[0054] Due to the reduction of the cross section of the overflow passage arrangement 9, the damping (also called damping force) exerted on the piston 8 as it moves in the cylinder 6 is increased. The piston movement, i.e. the movement of the piston 8 in the cylinder 6, is thereby countered. The damping thus counters the force introduced in the gas pressure element 4 which drives the drive connections 4a, 4b towards each other, so that the piston speed v is reduced, under the assumption that the force introduced in the gas pressure element 4 is constant or lower. The operating movement, in particular the closing movement, of the door 2 is thereby braked.

[0055] Here and preferably in this case: the lower limit value for the pressure gradient corresponds to a piston speed v in the range of 15 mm / s to 100 mm / s, preferably 30 mm / s to 80 mm / s, more preferably 40 mm / s to 60 mm / s, in particular 40 mm / s, and / or the upper limit value for the pressure gradient corresponds to a piston speed v in the range of 25 mm / s to 120 mm / s, preferably 40 mm / s to 100 mm / s, more preferably 50 mm / s to 80 mm / s, in particular 50 mm / s.

[0056] In this case, the damping force may be in the range of 100N to 800N, preferably 200 to 700N, more preferably 400N to 500N, in particular 450N, when the lower limit value of the pressure gradient is reached, and / or the damping force may be in the range of 300N to 3000N, preferably 500 to 2000N, more preferably 700N to 1500N, in particular 900N, when the upper limit value of the pressure gradient is reached.

[0057] From the rest state of the gas pressure element 4, the damping force rises during normal operation, preferably relatively slowly, for example from about 350 N when the piston is at rest to about 450 N at a piston speed v of 40 mm / s, until a lower limit value for the pressure gradient is reached. The damping force then rises, preferably relatively quickly, in the constriction state, until an upper limit value for the pressure gradient is reached, for example from about 450 N at a piston speed v of 40 mm / s to about 900 N at a piston speed v of 50 mm / s. Finally, the damping force then preferably remains approximately constant in the overload state, for example about 900 N at a piston speed v of more than 50 mm / s.

[0058] As already explained and shown in Fig. 3a), the valve device 10 assumes an open state in which the overflow channel arrangement 9 has a larger cross section in the narrowed state and / or a smaller cross section in the overload state during normal operation of the gas pressure element 4, in particular when the two drive connections 4a, 4b are driven towards each other. This also applies otherwise to the respective rest states of the gas pressure element 4 shown in Figs. 2a) and b), i.e. when the gas pressure element 4 is not operated and the two drive connections 4a, 4b are therefore stationary relative to each other, in which case no pressure gradient is present. Additionally or alternatively, in particular when the two drive connections 4a, 4b are driven towards each other, the valve device 10 can also be arranged such that, in the event of an increase in pressure gradient, the overflow channel arrangement 9 can be automatically switched from the open state in which the overflow channel arrangement 9 has a larger cross section in the narrowed state and / or a smaller cross section in the overload state, in particular via the narrowed state, to the overload state.

[0059] The automatic switching of the valve device 10 from the open state to the constricted state and possibly even to the overload state is preferably set in only one actuation direction of the gas pressure element 4, in particular an actuation direction which corresponds to the closing direction of the door 2. In principle, however, in a further embodiment not shown here, it is also possible that the automatic switching of the valve device 10 from the open state to the constricted state and possibly even to the overload state is additionally or alternatively set in an actuation direction which corresponds to the opening direction of the door 2.

[0060] The drive device 1 shown here, which is preferred in this respect, furthermore provides that the valve device 10 automatically switches from the overloaded state to the constricted state when a predefined upper limit value for the pressure gradient is exceeded and / or the valve device 10 automatically switches from the constricted state to the open state when a predefined lower limit value for the pressure gradient is exceeded. This applies in any case when the two drive connections 4a, 4b are driven towards one another, but also in particular when the two drive connections 4a, 4b are driven away from one another, for example by an optional drive spring device 12, which will be described below.

[0061] Thus, as shown for this embodiment in Fig. 2, the gas pressure element 4 here and preferably comprises a drive spring device 12, which comprises at least one first coil spring 13 and / or at least one second coil spring 14. The first coil spring 13 and / or the second coil spring 14 are in particular here compression or tension coil springs, which are preferably arranged parallel or coaxially to the cylinder 6. In particular, in this case the first coil spring 13 radially surrounds the cylinder 6. The second coil spring 14 is in particular radially surrounded by the cylinder 6 in this case.

[0062] At least one first coil spring 13 is preferably used for driving the drive connections 4a, 4b away from each other, the first coil spring 13 opposing the piston movement in particular over the entire range of motion of the piston 8, i.e. over the entire stroke of the piston 8. At least one second coil spring 14 opposing the piston movement, preferably only over the last part of the range of motion of the piston 8, when both drive connections 4a, 4b are driven towards each other.

[0063] The valve device 10 is here, and preferably, designed, possibly assisted by the drive spring device 12, in such a way that when the two drive connections 4a, 4b are driven towards one another, in an overload state the pressure gradient can be reduced particularly sharply, i.e. due to the widening of the cross section of the overflow passage device 9, until a predefined upper limit value for the pressure gradient is again fallen below, so that the valve device 10 automatically switches to the narrowing state.

[0064] "Can be reduced" means at least that the pressure gradient is reduced when the force introduced into the gas pressure element 4 and driving the drive connections 4a, 4b towards one another remains constant or decreases. This is the case, for example, when the force introduced into the gas pressure element 4 and driving the drive connections 4a, 4b towards one another results exclusively from the force due to the weight of the door 2. By bringing the valve device 10 into a constricted state due to a particularly sharp reduction in the pressure gradient and, due to the associated reduction in the cross section of the overflow channel device 9, the damping is increased, so that the piston movement and, correspondingly, the movement of the two drive connections 4a, 4b towards one another can be slowed down.

[0065] As mentioned, the valve device 10 can in this case be assisted by the drive spring device 12. This means that, when the two drive connections 4a, 4b are driven towards one another, the spring force of the drive spring device 12 opposes the piston movement, in particular preferably continuously via the first coil spring 13, and in particular additionally, and in some sections, via the second coil spring 14. The piston movement and accordingly the movement of the two drive connections 4a, 4b towards one another can thereby be additionally slowed down at least in limited partial regions of the pivoting movement of the door 2.

[0066] In this case, due to the particularly sharp decrease in the pressure gradient, the valve device 10 may even temporarily fall below the lower limit value for the pressure gradient, so that it goes beyond the narrowing state and temporarily switches into an open state and then switches back into the narrowing state, in which case the piston movement and, correspondingly, the movement of the two drive connections 4a, 4b towards one another may then be slowed down due to the reduction in the cross section of the overflow channel arrangement 9.

[0067] Basically, it is also possible to carry out the above-described switching process several times in order to slow down the closing movement of the car door 2 in the case of an overload. The valve device 10 in this case switches to a constriction state with increased damping due to a particularly sharp decrease in the pressure gradient, but then switches again to an overload state, as the pressure gradient rises again. In this overload state, the damping is reduced again. The valve device 10 then switches again to a constriction state with increased damping due to a new particularly sharp decrease in the pressure gradient. With each new switch to the constriction state, the piston speed v is in this case further reduced compared to the last time the valve device 10 was in the constriction state, and the pivoting movement of the door 2 is slowed down.

[0068] In order to slow down the pivoting movement of the door 2, as in the present embodiment, the drive spring device 12 is advantageously designed such that its spring force increases with a decrease in the distance between the two drive connections 4a, 4b, preferably in such a way that during the closing movement of the door 2, the decrease in the shortest vertical distance between the pivot axis X of the door 2 and the line of action of the spring force resulting in a moment acting on the door 2 is at least partially, preferably completely, compensated.

[0069] In this way, an optimum assistance of the valve device 10 by the spring device 12 is preferably provided over substantially the entire pivot area of ​​the door. Braking of the closing door can thus be performed even more effectively.

[0070] Below, therefore, a particularly preferred embodiment of the gas pressure element 4 will be explained on the basis of the illustration in FIG.

[0071] Thus, as already mentioned above, the piston 8 comprises a piston rod 8a and a base body 8b attached to the piston rod 8a, in particular axially fixed relative to the piston rod 8a, the base body 8b being in particular at least partially sealed against the cylinder inner surface. The valve device 10 on the other hand comprises here and preferably a valve body 15 movable relative to the base body 8b, in particular axially movable relative to the base body 8b, the valve body 15 being arranged in particular inside, preferably radially inside, the base body 8b. The valve body 15 is here and preferably radially surrounded by the base body 8b over at least a part of its axial extension, preferably the maximum part of its axial extension and even more preferably over its entire axial extension, at least in its open position, as further described below, in particular in each of the switching positions, as further described below. In the variant shown in Figures 4b) and 4c), the valve body 15 here and preferably extends axially outside the base body 8b over at least part of its axial extension, preferably over the maximum part of its axial extension, at least in its open position which will be described further below, and in particular in each of the switching positions which will be described further below.

[0072] In this case, the overflow conduit arrangement 9 is formed between the base body 8b and the valve body 15. The valve body 15 is here and preferably guided along the cylinder axis A against the base body 8b, in particular within the base body 8b.

[0073] The valve body 15 is here and preferably actuable in a plurality of switching positions relative to the base 8b of the piston 8, with at least one open position (FIG. 3a)) in which the valve device 10 occupies an open state, at least one constricted position (FIG. 3b)) in which the valve device 10 occupies a constricted state, and / or at least one overload position (FIG. 3c)) in which the valve device 10 occupies an overload state. For this purpose, the valve body 15 is here displaceable, preferably against a spring force, from its initial position (FIG. 2) which the valve body 15 occupies in the rest state of the gas pressure element 4 towards the piston rod 8a, as will be further explained below. Preferably, the valve body 15 may occupy, as here relative to the base 8b of the piston 8, a plurality of open positions in which the valve device 10 occupies an open state, a plurality of constricted positions in which the valve device 10 occupies a constricted state, and / or a plurality of overload positions in which the valve device 10 occupies an overload state. In this case, the valve body 15 may occupy multiple positions of the type "open position", multiple positions of the type "constricted position" and / or multiple positions of the type "overload position". Thus, here, both the initial position shown in Fig. 2 and the position shown in Fig. 3a) are each a position of the type "open position", i.e. an open position in which the valve device 10 occupies an open state.

[0074] The overflow conduit arrangement 9 thus has one or more fluid channels 11, which serve for the fluid-technical connection between the two partial chambers 7a, 7b. In both the overloaded and open states, these fluid channels 11 fluid-technically connect the two partial chambers 7a, 7b to one another. For this purpose, the fluid channels 11 extend between the base body 8b and the valve body 15. In one or more of the fluid channels 11, a narrowing 16 is provided or can be formed, which defines the smallest cross-section of the fluid channel 11 through which the compensation flow can flow. The respective cross-section of at least one or all of the narrowings 16 and / or the total cross-section of all of the narrowings 16 varies depending on the switching position (overloaded position, narrowing position, open position) of the valve body 15 relative to the base body 8b of the piston 8.

[0075] "Provided or formable" means, on the one hand, that a constriction 16 is always present in each fluid channel 11, and that when the valve body 15 is moved relative to the base body 8b, the radial contour of the constriction 16 varies section by section as a function of the switching position of the valve body 15, in particular due to the differently shaped material sections of the valve body 15, so that the cross section of this constriction 16 varies as a function of the switching position of the valve body 15. On the other hand, a fluid channel 11 that is not active in a certain switching position of the valve body 15, i.e. which does not fluidically connect the two partial chambers 7a, 7b to one another in this switching position and thus does not have a constriction 16 through which a flow can flow, is active in another switching position of the valve body 15, i.e. which fluidically connects the two partial chambers 7a, 7b to one another in this switching position, so that a constriction 16 is only formed as a result. This fluid passage 11 is then "opened", i.e. "open", and possibly another fluid passage 11 with a different cross-section at a narrowing 16 is then "blocked", i.e. is no longer active. The latter configuration can be realized, for example, by providing a number of fluid passages 11 of different lengths around the circumference of the valve body 15, which fluid passages 11 differ, in particular in the cross-section of their respective narrowings 16 in the active state, so that the compensating flow can flow through different fluid passages 11 or through a different number of fluid passages 11 depending on the switching position.

[0076] The total cross section is in this case the sum of all the cross sections of the individual narrowing points 16. The respective narrowing point 16, i.e. the point of the fluid channel 11 with the smallest possible cross section for flow therethrough at any one time, is displaced in the exemplary embodiment shown as a function of the switching position of the valve body 15, i.e. the narrowing point 16 is formed at another point of the valve body 15 or of the base body 8b depending on the switching position of the valve body 15.

[0077] In this case, here and preferably, one groove 17 is formed in the valve body 15 for each fluid channel 11. The narrowing point 16 of the fluid channel 11 is formed in this case, here and preferably, in one or more types of switching positions, in particular in the type "narrowed position" and / or "open position", i.e. in the narrowed position and / or open position, between a respective groove section 17a, 17b of the groove 17 and a counter element 18, in particular a sealing ring, provided on the basic body 8b. Additionally or alternatively, as in the present embodiment, in one type of switching position, in particular in the type "overload position", i.e. in the overload position, the narrowing point 16 of the fluid channel 11 is a ring chamber 19 between the valve body 15, here the chamfered material section 20, and a counter element 18, in particular a sealing ring, provided on the basic body 8b. The ring chamber 19 is in this connection a completely surrounding free space through which a fluid can flow.

[0078] The narrowing 16 of the fluid passage 11 is thus formed in a further section of the valve body 15, for example in the groove sections 17a, 17b or in the chamfered material section 20, in each of the mentioned switching positions of the valve body 15.

[0079] According to an alternative embodiment, not shown here, one groove 17 can also be formed in the base body 8b for each fluid channel 11, in which case the narrowing point 16 of the fluid channel 11 is preferably formed between a respective groove section 17a, 17b of the groove 17 and a counter element 18, in particular a sealing ring, on the valve body 15 in one or more types of switching positions, in particular of the type "constricted position" and / or "open position", i.e. in the constricted position and / or in the open position. In this case, additionally or alternatively, the narrowing point of the fluid channel 11 can also be an annular chamber 19 between the base body 8b and the counter element 18 on the valve body 15 in one type of switching position, in particular of the type "overload position", i.e. in the overload position.

[0080] As can be seen best in Fig. 3a), here and preferably the groove 17 has a first groove section 17a with a larger cross section and / or a larger depth and / or width followed by a second groove section 17b with a smaller cross section and / or a smaller depth and / or width. Here and preferably in this case the second groove section 17b opens into the surrounding chamfered or recessed material section 20. Alternatively, but this is not shown here, the second groove section 17b can also open into a third groove section with a larger cross section and / or a larger depth and / or width than the first and / or second groove sections 17a, 17b.

[0081] Here, and preferably as mentioned, the valve body 15 is the part in which the grooves 17 are provided to form the respective fluid passages 11. Correspondingly, the chamfered material section 20 here is also part of the valve body 15.

[0082] The chamfered material section 20 is a section of the valve body 15, the outer surface of which here does not run parallel to the axis of movement of the valve body 15, which runs coaxially to the cylinder axis A, but runs obliquely thereto. In this chamfered material section 20, the cross section of the valve body 15 is therefore reduced, in particular not only in a narrow circumferential segment, as in the groove 17, but also over a larger circumferential area, preferably over the complete circumference. The space available for flow through is therefore greater in the circumferential direction than in the groove 17. In this way, a considerably larger cross section available for flow of the overflow channel arrangement 9 is achieved in comparison with the groove 17, as shown in FIG. 3c). Preferably, this results in the aforementioned ring chamber 19 being formed between the surrounding chamfered material section 20 and the counter part 18, here the sealing ring, in the overload position.

[0083] The same effect as with the surrounding chamfered material section 20 can also be achieved with a surrounding recessed material section (not shown).

[0084] It should be emphasized again at this point that, in the presently preferred embodiment, the valve body 15 has the respective groove 17 and the chamfered material section 20. According to an alternative embodiment, not shown here, this can however also be provided in the base body 8b, in which case the respective counter element 18 or sealing ring, as mentioned, would be provided in the valve body 15.

[0085] As shown in Fig. 3, here and preferably the first groove section 17a is arranged towards the partial chamber 7b, in which the fluid has a lower pressure when the two drive connections 4a, 4b are driven towards one another. In particular, this first groove section 17a opens into the partial chamber 7b. The first groove section 17a is thus connected to the second groove section 17b towards the partial chamber 7a. The partial chamber 7a is in this case the partial chamber in which the fluid has a higher pressure when the two drive connections 4a, 4b are driven towards one another.

[0086] The concepts "smaller" and "larger" or "lower" and "higher" always relate to each other here, i.e. for example a "smaller" cross-section is smaller than a "larger" cross-section or a "lower" pressure is smaller than a "higher" pressure.

[0087] 3a), 3b) and 3c) show in this order that in the open state, the groove section 17a together with the counter element 18 or the sealing ring firstly forms a cross section through which the fluid flows in order to compensate the pressure gradient between the two partial chambers 7a, 7b. If the pressure gradient then increases, the valve body 15 is pushed towards the partial chamber 7b by the increased pressure in the partial chamber 7a, so that the constriction state is then achieved. In the constriction state, the groove section 17b together with the counter element 18 or the sealing ring then forms a cross section through which the fluid flows in order to compensate the pressure gradient between the two partial chambers 7a, 7b. If the pressure gradient then increases further, the valve body 15 is pushed even further towards the partial chamber 7b by the increased pressure in the partial chamber 7a, so that the overload state is then achieved. In the overload state, the chamfered material section 20 then together with the counter element 18 or the sealing ring forms a now ring-shaped cross section through which the fluid flows in order to compensate for the pressure gradient between the two partial chambers 7a, 7b.

[0088] 3 and 4, the valve body 15 is here biased by a force when it is displaced from its initial position which it occupies in the rest state of the gas pressure element 4. For this purpose, here and preferably a valve spring device 21 with at least one valve spring 22 is provided, which here cooperates with the valve body 15 in such a way that the valve body 15 is biased by a spring force from its initial position against the base body 8b, in particular preferably towards at least one of its open or initial positions.

[0089] Various variants of the valve spring arrangement 21 are shown in figures 4a) to c). Figure 4a) corresponds in this case to the variant also shown in figures 3a) to c). The variants shown differ in terms of the position of at least one valve spring 22 in the valve arrangement 10.

[0090] As shown in Fig. 3 or 4a), the valve spring 22, here and preferably a single valve spring 22 of the valve spring arrangement 21, is arranged on the side, in particular on the end face, of the valve body 15 facing the lower partial chamber 7b of the cylinder interior 7. The valve spring 22 is here and preferably supported at one end on the base body 8b or on the piston rod 8a, here on the radially inwardly projecting section 23, and at the other end on the valve body 15, here on the side, in particular on the end face, of the valve body 15 facing the lower partial chamber 7b of the cylinder interior 7. The valve spring 22 is here and preferably surrounded in the radial direction by the base body 8b over at least part of its axial extension, preferably over the greatest part of its axial extension and even more preferably over its entire axial extension.

[0091] 4b) and 4c), an axial section 24 of the valve body 15 projects axially from the base body 8b into the upper partial chamber 7a of the cylinder interior 7. This section 24 has, at a distance from the base body 8b and, in particular here, at its end facing away from the base body 8b, a radial extension 25 which forms an axial abutment for the valve spring 22, here and preferably a single valve spring 22 of the valve spring arrangement 21. The valve spring 22 is here and preferably arranged on the side of the base body 8b facing the upper partial chamber 7a of the cylinder interior 7, in particular on the end face, and / or surrounds the valve body 15 radially, in particular over its entire axial extension. The valve spring 22 is here and preferably supported at one end on the base body 8b, here on an end face of the base body 8b, and at the other end on the valve body 15, here on a radial extension 25 of the valve body 15. The valve spring 22 is in this case here and preferably arranged axially outside the base body 8b over at least part of its axial extension, preferably over the greatest part of its axial extension and even more preferably over its entire axial extension.

[0092] Basically, it is also possible to combine the above-mentioned variants, so that the valve spring arrangement 21 has at least two valve springs 22. One valve spring 22 is arranged in this case on the side of the valve body 15 facing the lower partial chamber 7b of the cylinder interior 7, in particular on the end face, as shown in FIG. 3 or 4a), and is preferably supported at one end on the base body 8b or the piston rod 8a, in particular on the radially inwardly projecting section 23, and at the other end on the valve body 15, in particular on the side of the valve body 15 facing the lower partial chamber 7b of the cylinder interior 7, in particular on the end face. The other valve spring 22 is arranged in this case on the side of the base body 8b facing the upper partial chamber 7a of the cylinder interior 7, in particular on the end face, as shown in FIG. 4b) or 4c), and / or surrounds the valve body 15 in the radial direction, in particular over its entire axial extension. This further valve spring 22 is preferably supported at one end on the base body 8 b , in particular on an end face of the base body 8 b , and at the other end on the valve body 15 , in particular on a radial extension 25 of the valve body 15 .

[0093] The radial extension 25 can be formed in various ways. As shown in FIG. 4b), the radial extension 25 is formed by a threaded nut 25a, which is screwed onto the valve body 15, in particular on the end side. Here, and preferably, one washer 25b is also a component part of the radial extension 25. The threaded nut 25a and / or the washer 25b in this case protrude into the axial projection of the spring material, in particular the spring wire, of the valve spring 22, so that the valve spring 22 can abut axially against the threaded nut 25a or, as here, against the washer 25b. As shown in FIG. 4c), the radial extension 25 is formed by a radial expansion of the material of the valve body 15, in particular at the end of the valve body 15 facing away from the base body 8b. The expanded material of the valve body 15 in this case protrudes into the axial projection of the spring material of the valve spring 22, in particular the spring wire, so that the valve spring 22 can abut axially against the expanded material.

[0094] The valve body 15 can be displaced to the left in Fig. 3 or 4a) and also in Fig. 4b) and 4c), respectively, towards the piston rod 8a and is correspondingly, at least in the displaced state, spring-biased to the right towards its at least one open position by the valve spring device 21. In the rest state of the gas pressure element 4 and during normal operation, the valve device 10 thus always assumes an open state here. In principle, the valve body 15 can be spring-free or spring-biased in the open state of the valve device 10.

[0095] As previously suggested, in a further embodiment not shown here, the described switching process is additionally or alternatively also possible in the opposite direction. The valve body 15 would in this case be additionally or alternatively displaceable in the opposite direction from its initial position which it occupies in the rest state of the gas pressure element 4, here away from the piston rod 8a, against a force, in particular against a spring force provided by the valve spring device 21.

[0096] In any case, it is here and preferably the case that: the respective valve spring 22 is compressed as a function of the pressure gradient between the two partial chambers 7a, 7b. The spring characteristic curve of the respective valve spring 22 is preferably selected for this purpose in such a way that, as a function of the piston speed v, the valve body 15 occupies the switching position (overloaded position, constricted position, open position) which corresponds in each case to the pressure gradient present. In particular, the spring characteristic curve of the respective valve spring 22 is selected in this case in such a way that, as a function of the piston speed v, the section of the valve body 15 which corresponds to the switching state (overloaded position, constricted position, open position) to be set in each case (overloaded position, constricted position, open position) faces the counter part 18, i.e., for example, in the overloaded position, the chamfered material section 20, in the constricted position, the groove section 17b and in the open position, the groove section 17a.

[0097] According to another idea of ​​independent significance, a drive 1 for a door 2, in particular a tailgate, of a motor vehicle, possibly with at least one motorized drive 3, is provided, which at least comprises one gas pressure element 4, in particular a gas spring, in the drive 1, the gas pressure element 4 having a cylinder 6 sealed towards the outside and a piston 8 running in a cylinder interior 7 along a cylinder axis A and dividing the cylinder interior 7 into two partial chambers 7a, 7b, the gas pressure element 4 having a first drive connection 4a connected to the cylinder 6 and a second drive connection 4b connected to the piston 8. The present invention claims a drive 1 having a second drive connection 4b connected to the cylinder 6, the cylinder 6 being filled with a fluid, in particular a fluid under pressure, the piston 8 having an overflow conduit arrangement 9 by means of which a compensating flow between the two partial chambers 7a, 7b occurs during the piston movement in order to compensate for the pressure gradient between the two partial chambers 7a, 7b, and a switchable valve arrangement 10 is assigned to the piston 8, which valve arrangement 10 can be switched into different through-flow states which differ in the size of the cross section of the overflow conduit arrangement 9 that can be passed through as a function of the pressure gradient between the two partial chambers 7a, 7b. Please refer to the full description of the drive 1 according to the present proposal according to the first concept.

[0098] According to this concept, in particular when the two drive connections are driven closer to each other, it is envisaged that the valve device 10 will automatically switch from an open state to a narrowing state in which the cross section of the overflow passage device 9 is reduced relative to the open state when a predefined lower limit value for the pressure gradient is exceeded, and will automatically switch from a narrowing state to a closed state in which the cross section of the overflow passage device 9 is reduced relative to the narrowing state when a predefined upper limit value for the pressure gradient is exceeded.

[0099] Preferably, in this case, the following occurs: after a predefined upper limit value for the pressure gradient has been exceeded, the cross section of the overflow channel arrangement 9 is at least largely, preferably completely, closed, so that it is no longer possible for a flow to pass through, or at any rate no longer possible for a flow to be mentioned.

[0100] According to another idea, which has an equally independent meaning, a door arrangement 5 is claimed, which comprises a door 2, in particular a tailgate, and a drive device 1 according to the proposal assigned to the door 2. Reference is made to the full description of the drive device 1 according to the first and second ideas.

[0101] In particular, the door 2 is a door 2 that can be pivoted about a pivot axis X, which is oriented approximately horizontally in the assembled state. In precisely this application, as explained above, the drive device 1 according to the proposal can be used particularly advantageously. This is particularly the case when the speed of the door 2 is increased, as explained above. In the door device 5 according to the proposal, such a case is in particular defined by the absence of the drive and / or holding force of the drive 3, whereby the door 2 is pushed in the closing or opening direction due to a spring force and / or due to gravity, or by the user manually closing the door, whereby the in this case conditional switching of the valve device 10 into the narrowed state as set by the first and second concepts, and possibly into the closed state as set by the second concept, opposes the further movement of the door 2, in particular prevents the further movement of the door 2.

Claims

1. A drive device for a door (2) of a motor vehicle, comprising at least one gas pressure element (4) having a cylinder (6) sealed towards the outside and a piston (8) running along a cylinder axis (A) in a cylinder interior (7) and dividing the cylinder interior (7) into two partial chambers (7a, 7b), the gas pressure element (4) has a first drive connection (4a) connected to the cylinder (6) and a second drive connection (4b) connected to the piston (8), the cylinder (6) being filled with a fluid, the piston (8) has an overflow passage arrangement (9) by means of which a compensating flow occurs between the two partial chambers (7a, 7b) in order to compensate for the pressure gradient between the two partial chambers (7a, 7b) in relation to the piston movement; and a switchable valve device (10) is assigned to the piston (8), which can be put into different through-flow states, which differ in the cross-sectional size of the overflow channel device (9), depending on the pressure gradient between the two partial chambers (7a, 7b). In the drive device, the valve device (10) automatically switches to a constriction state in which the cross section of the overflow passage device (9) is reduced when a predefined lower limit value for the pressure gradient is exceeded, and automatically switches to an overload state in which the cross section of the overflow passage device (9) is increased when a predefined upper limit value for the pressure gradient is exceeded. A drive device characterized by:

2. 2. The drive device according to claim 1, characterized in that after exceeding the predefined lower limit value for the pressure gradient, the cross section of the overflow channel arrangement (9) remains open or is closed again until reaching the predefined upper limit value for the pressure gradient.

3. 3. The drive device according to claim 1 or 2, characterized in that the lower limit value for the pressure gradient corresponds to a piston speed (v) in the range of 15 mm / s to 100 mm / s and / or the upper limit value for the pressure gradient corresponds to a piston speed (v) in the range of 25 mm / s to 120 mm / s.

4. 4. The drive device according to claim 1, wherein during normal operation of the gas pressure element, the valve device (10) occupies an open state in which the overflow passage device (9) has a larger cross-section in the narrowing state and / or a smaller cross-section in the overload state, and / or the valve device (10) is capable of switching automatically from an open state in which the overflow passage device (9) has a larger cross-section in the narrowing state and / or a smaller cross-section in the overload state to the overload state when a pressure gradient increases.

5. 5. The drive arrangement according to claim 4, characterized in that the valve device (10) automatically switches from the overloaded state to the constricted state when a predefined upper limit value for the pressure gradient is exceeded and / or the valve device (10) automatically switches from the constricted state to the open state when a predefined lower limit value for the pressure gradient is exceeded.

6. 6. The drive device according to claim 1, wherein the gas pressure element (4) comprises a drive spring device (12) having at least one first coil spring (13) arranged parallel to or coaxially with the cylinder (6) and radially surrounding the cylinder (6) and / or at least one second coil spring (14) arranged parallel to or coaxially with the cylinder (6) and radially surrounded by the cylinder (6).

7. 7. The drive device according to claim 1, wherein the valve device is designed in such a way that, when the two drive connections are driven closer to one another, in the overload state the pressure gradient can be reduced until the predefined upper limit value for the pressure gradient is again fallen below, so that the valve device automatically switches over to the narrowing state.

8. 7. Drive device according to claim 6, characterized in that the drive spring device (12) is designed such that its spring force increases with decreasing distance between the two drive connections (4a, 4b).

9. 9. The drive device according to claim 1, wherein the piston (8) has a piston rod (8a) and a base body (8b) attached to the piston rod (8a), the valve device (10) has a valve body (15) movable relative to the base body (8b), and the overflow passage device (9) is formed between the base body (8b) and the valve body (15).

10. 10. The drive device according to claim 9, wherein the valve body (15) is operable in a plurality of switching positions relative to the base body (8b) of the piston (8), the switching positions comprising at least one open position, in which the valve device (10) occupies an open state, at least one constriction position, in which the valve device (10) occupies the constriction state, and / or at least one overload position, in which the valve device (10) occupies the overload state.

11. 11. The drive device according to claim 10, wherein the overflow channel arrangement (9) has one or more fluid channels (11) which serve for the fluid-technical connection between the two partial chambers (7a, 7b) and which extend between the base body (8b) and the valve body (15), and wherein in one or more of the fluid channels (11) a narrowing (16) is provided or can be formed, which narrowing (16) determines the smallest cross-section of the fluid channel (11) through which the compensation flow can flow, and wherein the respective cross-section of at least one narrowing (16) or of all narrowing points (16) and / or the total cross-section of all narrowing points (16) varies as a function of the switching position of the valve body (15) relative to the base body (8b) of the piston (8).

12. A groove (17) is formed in the valve body (15) for each fluid passage (11).

12. The drive arrangement according to claim 11, characterized in that

13. 13. The drive device according to claim 12, characterized in that the groove (17) has a first groove section (17a) with a larger cross-section and / or a larger depth and / or width and, following the first groove section (17a), a second groove section (17b) with a smaller cross-section and / or a smaller depth and / or width.

14. 14. The drive device according to claim 9, wherein the valve body (15) is biased by a force against the base body (8b) in at least one of its constriction and overload positions.

15. A drive device for a door (2) of a motor vehicle, comprising at least one gas pressure element (4) having a cylinder (6) sealed towards the outside and a piston (8) running along a cylinder axis (A) in a cylinder interior (7) and dividing the cylinder interior (7) into two partial chambers (7a, 7b), the gas pressure element (4) has a first drive connection (4a) connected to the cylinder (6) and a second drive connection (4b) connected to the piston (8), the cylinder (6) being filled with a fluid, the piston (8) has an overflow passage arrangement (9) by means of which a compensating flow occurs between the two partial chambers (7a, 7b) in order to compensate for the pressure gradient between the two partial chambers (7a, 7b) in relation to the piston movement; and a switchable valve device (10) is assigned to the piston (8), which can be put into different through-flow states, which differ in the cross-sectional size of the overflow channel device (9), depending on the pressure gradient between the two partial chambers (7a, 7b). In the drive device, the valve device (10) automatically switches from an open state to a narrowing state in which the cross-section of the overflow passage device (9) is reduced relative to the open state when a predefined lower limit value for the pressure gradient is exceeded, and automatically switches from the narrowing state to a closed state in which the cross-section of the overflow passage device (9) is reduced relative to the narrowing state when a predefined upper limit value for the pressure gradient is exceeded. A drive device characterized by:

16. 16. Drive device according to any one of the preceding claims, characterized in that the door (2) is a tailgate.

17. 17. Drive device according to any one of the preceding claims, characterized in that the cylinder (6) is filled with a fluid under pressure.

18. 18. The drive device according to claim 3, wherein the lower limit value for the pressure gradient corresponds to a piston speed (v) in the range from 30 mm / s to 80 mm / s and / or the upper limit value for the pressure gradient corresponds to a piston speed (v) in the range from 40 mm / s to 100 mm / s.

19. 6. The drive arrangement according to claim 4 or 5, characterized in that the valve device (10) is capable of switching automatically from the open state, via the constricted state, to the overloaded state when a pressure gradient increases.

20. 20. The drive device according to claim 6, wherein the at least one first coil spring (13) and / or the at least one second coil spring (14) are compression coil springs or tension coil springs.

21. 9. The drive device according to claim 8, characterized in that the drive spring device (12) is designed in such a way that its spring force increases with a decrease in the distance between the two drive connections (4a, 4b) so that during the closing movement of the door (2), a decrease in the shortest vertical distance between the pivot axis (X) of the door (2) and the line of action of the spring force resulting in a moment acting on the door (2) is partially or completely compensated.

22. 15. The drive device according to claim 9, wherein the valve body (15) is arranged inside the base body (8b).

23. 14. The drive device according to claim 12 or 13, characterized in that the narrowed point (16) of the fluid passage (11) is formed between a respective groove section (17a, 17b) of the groove (17) and a counter element (18) provided on the base body (8b) in the narrowed position and / or in the open position and / or is an annular chamber (19) between the valve body (15) and a counter element (18) provided on the base body (8b) in the overload position.

24. 14. Drive device according to claim 12 or 13, characterized in that in the base body (8b) one groove (17) is formed for each fluid passage (11).

25. 25. The drive device according to claim 24, wherein the narrowing point (16) of the fluid passage (11) is formed between a respective groove section (17a, 17b) of the groove (17) and a counter element (18) on the valve body (15) in the narrowed position and / or in the open position and / or is an annular chamber (19) between the base body (8b) and the counter element (18) on the valve body (15) in the overload position.

26. 26. The drive unit according to claim 23 or 25, wherein the counter member (18) provided on the base body (8b) is a seal ring.

27. 14. The drive device according to claim 13, characterized in that the second groove section (17b) opens into a surrounding chamfered or recessed material section (20) or into a third groove section having a larger cross section and / or a larger depth and / or width than the first and / or second groove sections (17b).

28. 27. The drive device according to claim 23, 25 or 26, characterized in that in the overload position, the ring chamber (19) is formed between a surrounding chamfered or recessed material section (20) and the counter-part (18).

29. 15. The drive device according to claim 14, characterized in that the valve body (15) is biased by a force against the base body (8b) via a valve spring device (21) having at least one valve spring (22) in each case at least in one of its constriction and overload positions.

30. 30. The drive device according to claim 14 or 29, characterized in that the valve body (15) is biased towards at least one of its open positions by a force relative to the base body (8b) in any case at least one of its constricted and overload positions.

31. 31. The drive device according to claim 29 or 30, characterized in that a valve spring (22) is arranged on the side of the valve body (15) facing the lower partial chamber (7b) of the cylinder interior (7) and is supported at one end on the base body (8b) or on the piston rod (8a) and at the other end on the valve body (15) and / or a valve spring (22) is arranged on the side of the base body (8b) facing the upper side of the cylinder interior (7) facing the partial chamber (7a) and is supported at one end on the base body (8b) and at the other end on the valve body (15).

32. A door device comprising a door (2) and a drive device (1) according to any one of claims 1 to 31, assigned to the door (2).

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