Drive assembly for a cover of a motor vehicle

Abstract

This invention relates to a drive assembly for a cover (2) of a motor vehicle, having at least one gas pressure element (4), particularly a gas spring, wherein the gas pressure element (4) has an outwardly sealed cylinder (6) and a piston (8) that divides the cylinder interior space (7) into two subspaces (7a, 7b) along the cylinder axis (A) within the cylinder interior space (7), wherein the gas pressure element (4) has a first drive coupling (4a) connected to the cylinder (6) and a second drive coupling (4b) connected to the piston (8), wherein, The cylinder (6) is filled with fluid, particularly under pressure, wherein the piston (8) has an overflow channel assembly (9) through which a balanced flow is generated between two subspaces (7a, 7b) for piston movement to balance the pressure drop between the two subspaces (7a, 7b), and wherein the piston (8) is associated with a switchable valve assembly (10) which can be placed in different flow states depending on the pressure drop between the two subspaces (7a, 7b), the flow states being different in terms of the cross-sectional size of the overflow channel assembly (9). It has been proposed that when a predetermined upper limit of the pressure drop is exceeded, the valve assembly (10) automatically switches to an overload state, in which the valve assembly increases the cross-sectional area of ​​the overflow channel assembly (9).

Description

Technical Field

[0001] The present invention relates to a drive assembly for a cover (klappe) for a motor vehicle, particularly a rear cover, a drive assembly for a cover for a motor vehicle, particularly a rear cover, and a cover assembly having a cover, particularly a rear cover, and such a drive assembly. Background Technology

[0002] The drive components discussed are used in the framework of any cover, especially a motorized adjustment, of a motor vehicle. Such covers can be, for example, rear covers, rear hoods, engine hoods, cargo floor, but can also be doors of the motor vehicle. In this regard, the term "cover" should be interpreted broadly.

[0003] The present invention is based on a known drive assembly (DE 10 2018 122 135 A1) for the motorized adjustment of a rear cover of a motor vehicle. On one side of the rear cover, the drive assembly has a motorized drive device in the form of a spindle drive mechanism. This drive mechanism has an electric drive unit and a spindle-spindle nut transmission mechanism rear-mounted in the electric drive unit. This drive mechanism generates a linear drive motion between a drive coupling on the vehicle body side and a drive coupling on the cover side for opening and closing the cover. In the open position of the cover, the spindle drive mechanism is in an extended position, and in the closed position of the cover, the spindle drive mechanism is in a retracted position.

[0004] Because the weight of the rear cover can be quite significant, a gas pressure element in the form of a gas spring is arranged on the opposite side of the cover, separate from the spindle drive, to compensate for the weight of the rear cover. Therefore, it is generally desirable for the rear cover to always be near equilibrium or to be pushed in the opening direction. Such a cover assembly, with a motorized drive on one side and a gas pressure element (in this case, a gas spring) on ​​the other side, is also called an active / passive system.

[0005] The advantage of the known gas pressure element in the drive assembly is that, in the event of failure of the driving force and / or holding force of the drive device, and the cover being pushed in the closing direction by elastic force and / or gravity, the gas pressure element switches the valve assembly to a closed state via a switchable valve assembly. This closed state resists and, in particular, prevents further adjustment of the cover. The switching to the closed state depends on pressure (i.e., on the pressure drop between the two sub-spaces in the gas pressure element), which in turn depends on the piston speed, i.e., the speed of the piston relative to the cylinder of the gas pressure element. However, in the case of a large force being applied, resulting in a high piston speed and the gas pressure element being blocked, the pressure in one of the two sub-spaces divided by the piston may exceed a critical pressure, which could lead to damage to the gas pressure element. Summary of the Invention

[0006] The problem upon which this invention is based is to design and improve known drive components in a way that minimizes damage to gas pressure elements.

[0007] The above-mentioned problems are solved by the driving component according to the present invention.

[0008] Firstly, the gas pressure element generally refers to an element having a cylinder and a piston guided coaxially with its cylinder axis within the cylinder, which provides pneumatic and / or hydraulic pressure, particularly static and / or dynamic pressure, between the cylinder and the piston of the gas pressure element, in a state of no movement and / or movement. The cylinder is filled with at least one fluid, particularly a gas and / or liquid, which can be filled into the cylinder under pressure (i.e., at a pressure higher or lower than ambient pressure) or without pressure (i.e., at a pressure substantially corresponding to ambient pressure). Preferably, the gas pressure element is formed solely by a gas spring, particularly a gas pressure spring or a gas tension spring, i.e., a cylinder-piston assembly in which the piston is filled with fluid under pressure, particularly overpressure. The gas pressure element can also be formed by a gas damper, i.e., a cylinder-piston assembly in which the piston is filled with unpressurized fluid. A gas pressure element may also have a cylinder-piston assembly, especially a gas spring and / or a gas damper, as one component, and additionally a drive elastic component that is parallel or coaxial with the cylinder axis and thus acts in the direction of action of the gas pressure element, gas spring, or gas damper as another component. In this regard, the terms "gas pressure element," "gas spring," and "gas damper" should be interpreted broadly.

[0009] In normal operation, the gas spring or gas damper of the gas pressure element according to the proposed scheme operates like a conventional gas spring or conventional gas damper, having in its usual manner a cylinder filled with fluid, especially gas and / or liquid, and a piston guided within the cylinder. Therefore, the gas pressure element utilizes the compressibility of the filled fluid, especially gas, for its elastic or damping action. In the case of the gas spring (where, when no force is applied, the fluid under pressure presses against the cross-section of the piston, thereby driving the cylinder-side drive coupling and the piston-side drive coupling apart), the gas spring is connected to the vehicle via the respective drive couplings. If a certain minimum pressure is introduced into the gas spring from the outside via the drive couplings, for example by manual operation of the rear cover or by operation caused by a motorized drive mechanism, the two drive couplings are driven to come together. In the case of a gas damper (where the fluid is pressureless when there is no input force), the drive coupling can move relative to each other only by means of pressure or tension introduced from the outside through the drive coupling, such as by manual operation of the rear cover or by operation caused by a motor drive, thereby the fluid is pressure-loaded through the cross-section of the piston.

[0010] The piston, and especially its base, also known as the piston head, divides the internal space of the cylinder into two sub-spaces, both in the case of a gas spring and a gas damper. The overflow channel assembly, formed, at least partially by the base, facilitates fluid flow from one sub-space to the corresponding other sub-space to balance the pressure drop between the sub-spaces. This flow is hereinafter referred to as the balanced flow.

[0011] Now, when a relatively large force is introduced into the gas pressure element, for example when the driving force and / or holding force of the drive unit fails and the cover is thus pushed in the closing direction by elastic force and / or gravity, or when the user manually closes the cover, the piston speed can increase. What may occur here is that the balancing flow cannot flow quickly enough through the previous cross-section of the overflow channel assembly from one sub-space to another because the cross-section is too small for this purpose. Consequently, the pressure in one of the sub-spaces increases, and therefore the pressure drop between the two sub-spaces increases.

[0012] The primary consideration now is that, based on the pressure drop between the two subspaces, before a critical pressure is generated in one of the subspaces, the switchable valve assembly automatically switches to a state that causes a particularly rapid pressure equilibrium between the subspace with the higher pressure and the subspace on the other side of the piston. This state to which the valve assembly switches is hereby referred to as the overload state. Therefore, even when a large force is introduced into the gas pressure element, resulting in a high piston speed, the gas pressure element can be optimally protected from damage or even destruction in this way.

[0013] During normal operation of the gas pressure element (which will be explained later), pressure balancing also occurs between the two sub-spaces separated by the piston within the gas pressure element, wherein, however, the balancing flow generated between the two sub-spaces is not as large as in the overload state. Furthermore, the valve assembly (also explained later) can switch to a state that reduces the balancing flow when the pressure in one of the sub-spaces increases to a certain level. This state is hereinafter referred to as the constriction state. If the pressure in that sub-space subsequently increases further, the valve assembly then switches to the overload state. It should be emphasized that the switching process is automatic, i.e., without user assistance and solely or primarily caused by the pressure drop between the two sub-spaces, which in turn depends on the piston speed.

[0014] Specifically, it is proposed that the valve assembly automatically switches to an overload state when the pressure drop exceeds a predetermined upper limit, in which the valve assembly increases, in particular, the cross-section of the overflow channel assembly.

[0015] This invention defines the possibility of switching to the previously mentioned narrowed state. Here, the cross-section of the overflow channel assembly is reduced, and in particular minimized.

[0016] The present invention defines a preferred piston speed at which the valve assembly switches to a constriction state and an overload state.

[0017] This invention relates to the open state of a valve assembly, which is present during normal operation of a gas pressure element, but also during the stationary state of the gas pressure element. When the pressure drop increases due to the increased piston speed, the valve assembly first switches from the open state to the closed state, and when the pressure drop further increases due to the still-increasing piston speed, the valve assembly further switches to an overload state.

[0018] The invention further describes how the valve assembly preferably behaves when the pressure drop decreases again. Therefore, the valve assembly switches from an overload state to a constricted state, and / or from a constricted state to an open state.

[0019] This invention relates to a drive elastic assembly, which preferably drives apart a drive coupling of a gas pressure element, which is secured to a cover on one side and to the vehicle body on the other. The drive elastic assembly may also include a helical spring, particularly within the cylinder of the gas pressure element, which acts as a spring-loaded spring, resisting piston movement only on a portion of the piston's motion within the cylinder, and should facilitate opening the cover from the closed position.

[0020] This invention describes a valve assembly preferably capable of rapidly reducing pressure drop under overload conditions and then automatically switching to a constricted state, thereby preventing a person from being trapped when the lid is closed. The actuating elastic component can additionally brake the lid by means that the elastic force increases as the distance between the two actuating couplings relative to each other decreases, thereby generating a torque resisting the closing movement of the lid via the elastic force. This is preferably done such that, during the closing movement of the lid, at least partially compensates for the reduction in the shortest vertical distance between the lid's pivot axis and the line of action of the elastic force.

[0021] The present invention relates to the basic structure of a valve assembly, and in particular defines a valve body that can be displaced relative to the base of the piston according to pressure drop and piston speed.

[0022] The subject of this invention is a particularly preferred design for the overflow channel assembly, and especially for the valve body and the substrate.

[0023] According to another preferred design of the invention, the valve body, in particular via the valve elastic component, is force-loaded relative to the base in at least one of its constricted and overloaded positions toward at least one of its open positions.

[0024] According to another teaching of independent significance of the present invention, a drive assembly for a cover, particularly a rear cover, of a motor vehicle is claimed. This drive assembly has at least one gas pressure element, particularly a gas spring, wherein the gas pressure element has an outwardly sealed cylinder and a piston that travels along the cylinder axis within the cylinder's internal space, dividing the cylinder's internal space into two sub-spaces. The gas pressure element has a first drive coupling connected to the cylinder and a second drive coupling connected to the piston. The cylinder is filled with fluid, particularly under pressure. The piston has an overflow channel assembly through which a balanced flow is generated between the two sub-spaces to balance the pressure drop between the two sub-spaces. The piston is associated with a switchable valve assembly that can be placed in different flow states depending on the pressure drop between the two sub-spaces, the flow states differing in the cross-sectional size of the overflow channel assembly. Reference can be made to all descriptions related to the drive assembly according to the first teaching and the present invention.

[0025] Importantly, the valve assembly automatically switches from an open state to a constricted state when the pressure drop exceeds a predetermined lower limit, in which the valve assembly reduces the cross-section of the overflow passage assembly relative to the open state. Similarly, when the pressure drop exceeds a predetermined upper limit, the valve assembly automatically switches from a constricted state to a closed state, in which the valve assembly reduces the cross-section of the overflow passage assembly relative to the constricted state. Here, the cross-section thus initially decreases in the constricted state, as in the first teaching, but subsequently, unlike in the first teaching, further decreases in the closed state.

[0026] According to another teaching of the present invention, which is also of independent significance, protection is claimed for a cover assembly having a cover, particularly a rear cover, and a drive assembly according to the present proposal mating with the cover. Reference may be made to all descriptions relating to the drive assembly according to the first teaching and the drive assembly according to the second teaching.

[0027] Preferably, the cover is pivotable about a pivot axis that is substantially horizontal in the assembled state. The gas pressure element particularly preferably pre-tightens the cover, especially in its opening direction. The cover assembly is particularly configured to have a drive mechanism, especially a linear drive mechanism, preferably a spindle drive mechanism, on a first side of the cover, and a gas pressure element on the opposite side. In this regard, the drive assembly is particularly an active / passive system. Attached Figure Description

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

[0029] Figure 1 The rear region of a motor vehicle having a cover assembly according to the present invention is shown, the cover assembly being equipped with a drive assembly according to the present invention.

[0030] Figure 2 It shows that according to Figure 1 A cross-sectional view of the gas pressure element of the drive assembly in a static state, a) after the drive coupling is driven to move closer and b) after the drive coupling is driven to move apart to its end position.

[0031] Figure 3 The enlarged diagram shows the data based on... Figure 1 Cross-sectional views of the valve assembly of the gas pressure element, a) in the open state, b) in the constricted state, and c) in the overload state, and

[0032] Figure 4 The enlarged diagram shows the data based on... Figure 1 Cross-sectional views of the valve assembly of the gas pressure element, a) in the first variant, b) in the second variant, and c) in the third variant. Detailed Implementation

[0033] The drive assembly 1 according to the present invention is used here and preferably for the motorized adjustment of the cover 2 of a motor vehicle. However, in an alternative embodiment, the drive assembly 1 according to the present invention may also be purely elastically driven, in the case of providing at least one gas spring, or it may be purely manually operable, in the case of providing at least one gas damper. The cover 2 can be adjusted in the opening and / or closing direction by means of the drive assembly 1.

[0034] Cover 2 is, and preferably, the rear cover of a motor vehicle. The drive assembly 1 according to the present invention can be used particularly advantageously in the case of the "rear cover" application, because the rear cover has a relatively large weight.

[0035] However, in principle, the drive component 1 according to this proposed solution can also be applied to other types of covers 2 for motor vehicles. This includes rear covers, engine hoods, etc., but also doors. All design solutions are accordingly applicable to other covers.

[0036] like Figure 1 As shown, the drive assembly 1 according to the proposed solution here and preferably has one, exactly one, motor drive device 3. The motor drive device 3, as will be explained in more detail below, here and preferably is a linear drive device, especially a spindle drive device.

[0037] Furthermore, the drive assembly 1 according to this proposal has one, specifically one, gas pressure element 4. The gas pressure element 4 is here and preferably a gas spring, especially a gas pressure spring. Here and preferably, the gas spring pre-tightens the cover 2 in its opening direction. The gas spring can also, in principle, be a gas tension spring. It is also conceivable that the gas pressure element 4 is a gas damper, i.e., without elasticity.

[0038] In the embodiment described herein, a gas spring is now exemplaryly provided as the gas pressure element 4. However, the description in this regard also applies to the other gas pressure elements 4 mentioned.

[0039] In principle, the drive assembly 1 according to this proposed scheme can also have more than one motor drive device and / or more than one gas pressure element 4. Figure 1 In the cover assembly 5 shown, in addition to the cover 2 of the motor vehicle, it also has a drive assembly 1, a motor drive device 3 is arranged on the first side of the cover 2, and a gas pressure element 4 or a gas spring is arranged on the opposite second side of the cover 2.

[0040] The motorized drive unit 3 (which forms the active side of the active / passive system here) is provided for opening and closing the cover 2. For this purpose, the drive unit 3 has a drive unit (not shown here) with an electric drive motor and, if necessary, one or more additional drive components, such as an intermediate transmission, an overload clutch, and / or a brake. Preferably, the drive unit is technically rear-mounted with a linear transmission device (also not shown), particularly a spindle-spindle nut transmission device, which, as a transmission component, specifically has a spindle and a spindle nut meshing with it. Preferably, the spindle is technically connected to the drive unit and is rotated during operation, thereby causing the spindle nut to perform linear movement along the spindle.

[0041] The motorized drive unit 3, having a drive unit and a linear transmission, particularly a spindle-spindle-nut transmission, has a first drive coupling 3a, particularly on the spindle side, and a second drive coupling 3b, particularly on the spindle-nut side, via which the drive unit 3 is connected to the motor vehicle. Preferably, the drive unit 3 is connected to the cover 2 via the drive coupling 3a on the spindle side, and to the vehicle body via the drive coupling 3b on the spindle-nut side. The linear drive motion of the linear transmission either drives the drive couplings 3a and 3b apart, corresponding to the adjustment movement of the cover 2 in its opening direction, or drives the drive couplings 3a and 3b together, corresponding to the adjustment movement of the cover 2 in its closing direction.

[0042] The gas spring that forms the gas pressure element 4 (which forms the passive side of the active / passive system) does not have its own motor drive, but instead provides an elastic function. Therefore, the gas spring should bear a portion of the weight of the cover 2, thereby keeping the cover 2 near its equilibrium state when it is opened or pushing the cover in the opening direction.

[0043] The gas pressure element 4 typically comprises an externally sealed cylinder 6 and a piston 8 that travels along the cylinder axis A within an internal space 7 radially surrounded by the cylinder 6, dividing the internal space 7 into two subspaces 7a, 7b. The piston 8 has a piston rod 8a that extends along the cylinder axis A and is movable relative to the cylinder 6. The piston rod 8a sealably penetrates an axial opening in the cylinder 6, thereby placing one section of the piston rod 8a within the internal space 7 and the other section outside the cylinder 6. The piston 8 further comprises a base 8b at the section of the piston rod 8a disposed within the internal space 7, particularly at its front end, which forms, in particular, a piston head. The base 8b here, and preferably, has a cross-section relating to a section in the radial direction of the cylinder 6, which corresponds to the cross-section of the internal space 7.

[0044] The gas pressure element 4 also has a first drive coupling 4a connected to the cylinder 6 and a second drive coupling 4b connected to the piston 8. The cylinder 6 is filled with fluid under pressure such that the two drive couplings 4a, 4b are driven apart. The fluid is in particular a compressible gas, and may preferably also contain a small amount of liquid (such as oil) if necessary, to cause, for example, end-position damping.

[0045] In the unloaded state, that is, when no force is applied to the gas pressure element 4 from the outside, the two drive couplings 4a and 4b are therefore in a state of... Figure 1 and Figure 2 The maximum driving separation position is shown in sub-figure b). This position of the driving couplings 4a and 4b relative to each other, and preferably also corresponds to the position of the cover 2. Figure 1 The open position is shown in the diagram. The drive coupling 4a on the cylinder side is connected to the cover 2, and the drive coupling 4b on the piston side is connected to the vehicle body. It should be emphasized again that, as mentioned above, the cylinder 6 can also be pressureless, i.e., with a gas damper instead of a gas spring.

[0046] The piston 8 has an overflow channel assembly 9 through which a balanced flow is generated between the two subspaces 7a and 7b in response to the piston movement, so as to balance the pressure drop between the two subspaces 7a and 7b.

[0047] In normal operation, this is the case now, so that when an external force drives the drive couplings 4a, 4b together, for example, when the cover 2 is closed mechanically or manually, the piston 8 relative to the cylinder 6 moves from... Figure 2 The position deflection shown in subgraph b) is that, in Figure 2 The piston 8 is deflected in the direction shown in sub-figure a). The section of piston 8 arranged in the cylinder interior space 7 is thus displaced along cylinder axis A through the cylinder interior space 7, thereby changing the volume of the two sub-spaces 7a and 7b of the cylinder interior space 7. (As shown in sub-figure a) Figure 2 It can be seen that in this embodiment, when the driving connecting parts 4a and 4b are driven to approach each other, the volume of subspace 7a decreases, while the volume of subspace 7b increases. Here, as... Figure 3 As shown in the detailed view in sub-figure a), fluid flows as a balanced flow from the upper subspace 7a through the overflow channel assembly 9 into the lower subspace 7b. Since the fluid is filled into the cylinder 6 here, and preferably under pressure, the fluid presses against the cross-section of the piston 8 (here, the base 8b), thereby continuously pressing the piston 8 relative to the cylinder 6. Figure 2The position is shown in sub-figure b). The reason for this is that the cross-sectional area of ​​the piston 8 or base 8a is larger on the side away from the piston (in this case, towards subspace 7a) than on the opposite side, because on the opposite side, the cross-sectional area loaded by fluid pressure is formed only by the ring extending around the piston rod 8a. The annular surface acting on one side of subspace 7b is smaller than the surface acting on one side of subspace 7a, which corresponds to the entire cross-section of the cylinder interior space 7. Accordingly, greater pressure acts on the piston 8 or base 8b from one side of subspace 7a compared to the other side, thereby continuously pushing the piston 8 out of the cylinder 6.

[0048] Piston 8 is now equipped with a switchable valve assembly 10, which can be placed in different flow states depending on the pressure drop between the two subspaces 7a, 7b, the flow states differing in the size of the cross-section of the overflow channel assembly 9. The cross-section of the overflow channel assembly 9 refers to the cross-section that allows flow under pressure equilibrium for the purpose of balancing flow. This is such that when the two drive couplings 4a, 4b are driven closer, the pressure drop varies according to the piston speed v (i.e., the speed at which piston 8 moves relative to cylinder 6). As the piston speed v increases, the balancing flow is no longer able to balance the pressure drop between the two subspaces 7a, 7b quickly enough, causing the pressure in one of the subspaces (in this case, subspace 7a) to continue to increase. Accordingly, the pressure acting on the base 8b and the valve assembly 10 increases, causing the valve assembly 10 to switch to another flow state, which will be explained in more detail later.

[0049] It is now important that, especially when the two drive couplings 4a, 4b are driven to come together, the valve assembly 10 automatically switches to an overload state when the pressure drop exceeds a predetermined upper limit. In this overload state, the valve assembly increases, and in particular maximizes, the cross-section of the overflow channel assembly 9.

[0050] The cross-section of the overflow channel assembly 9 (referring to the cross-section perpendicular to the flow direction of the balanced flow) is defined as follows: If the overflow channel assembly 9 has multiple fluid channels 11 for fluid-technically connecting the two subspaces 7a, 7b, i.e. guiding the balanced flow through, then the cross-section of the overflow channel assembly 9 corresponds to the sum of all the narrowest cross-sections of the fluid channels 11, i.e., the total cross-section formed by the sum of all individual cross-sections at the corresponding narrowest portion of the fluid channel 11. If the overflow channel assembly 9 has only one such fluid channel 11, then the cross-section of the overflow channel assembly 9 corresponds to the cross-section at the corresponding narrowest portion of that fluid channel 11.

[0051] "Valve assembly 10 increases the cross-section of overflow channel assembly 9" means that the cross-section of overflow channel assembly 9 becomes larger than the cross-section in the previous through-flow state (i.e., the narrowed state described later). "Maximize" means that the cross-section of overflow channel assembly 9 not only becomes larger, but also achieves the maximum cross-section that overflow channel assembly 9 can provide (by the sum of all the narrowest cross-sections).

[0052] Valve assembly 10 then functions as an overpressure valve. If the pressure in subspace 7a becomes excessive due to a particularly high piston speed v, i.e., if it exceeds a predetermined upper limit of the pressure drop, valve assembly 10 is opened and a particularly rapid pressure balance is achieved between subspaces 7a and 7b. This pressure balance prevents damage to the gas pressure element 4 when a very large force suddenly and rapidly drives the two drive couplings 4a, 4b together under overload conditions, thereby increasing the piston speed v.

[0053] exist Figure 3 The above function is shown in sub-figure c), according to which valve assembly 10 can be switched to an overload state. Figure 3 Sub-figure a) shows the open state of valve assembly 10, which is described in more detail below, during normal operation of gas pressure element 4. Figure 3 Subgraph b) shows the state of valve assembly 10 between the open state and the overload state, which will be described below as the so-called narrowing state.

[0054] Therefore, and preferably, especially when the two drive couplings 4a, 4b are driven to approach, the valve assembly 10 automatically switches to the narrowing state when a predetermined lower limit of the pressure drop is exceeded. In this narrowing state, the valve assembly reduces, and in particular minimizes, the cross-section of the overflow channel assembly 9. And preferably, after exceeding the predetermined lower limit of the pressure drop, and until reaching a predetermined upper limit of the pressure drop, i.e., in the narrowing state, the cross-section of the overflow channel assembly 9 remains open, but with a smaller cross-section. Therefore, the overflow channel assembly 9 remains flow-through. However, in principle, according to another embodiment not shown here, it is also conceivable that the cross-section of the overflow channel assembly 9 is closed, and thus no longer flow-through. Therefore, the narrowing state is not necessarily a flow-through state where the cross-section is merely reduced compared to the previous flow-through state, but rather that the cross-section can also be completely closed. Valve assembly 10 then remains in a constricted state until an overload occurs due to the further increase in piston speed v and the resulting pressure drop, i.e., valve assembly 10 switches to an overload state, or until gas pressure element 4 switches back to normal operation, as piston speed v and the corresponding pressure drop decrease, for example by removing the additional force acting on cover 2, especially during the closing process.

[0055] "Valve assembly 10 reduces the cross-section of overflow channel assembly 9" means that the cross-section of overflow channel assembly 9 becomes smaller than its cross-section in the previous flow-through state (i.e., the open state described later). "Minimize" means that the cross-section of overflow channel assembly 9 not only becomes smaller, but also achieves the minimum cross-section that overflow channel assembly 9 can provide (by the sum of all the narrowest cross-sections). As indicated, the minimum cross-section can also mean that overflow channel assembly 9 is subsequently closed and is not flow-through.

[0056] "Exceeding the predetermined lower limit" here means that the pressure drop continues to increase until it reaches the predetermined lower limit, but this does not yet cause valve assembly 10 to switch. Valve assembly 10 switches automatically when the lower limit is exceeded, thereby reducing the cross-section of overflow channel assembly 9.

[0057] By reducing the cross-section of the overflow channel assembly 9, the damping force acting on the piston 8 when it moves in the cylinder 6 is increased. This damping force resists the piston's movement (i.e., the movement of the piston 8 in the cylinder 6). Therefore, the damping resists the force introduced into the gas pressure element 4 and drives the drive couplings 4a and 4b together, thereby reducing the piston speed v, assuming the force introduced into the gas pressure element 4 is constant or less. Consequently, the adjusting movement of the cover 2, especially the closing movement, is braked.

[0058] Here, and preferably here, the lower limit of the pressure drop 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, especially 40 mm / s, and / or the upper limit of the pressure drop 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, especially 50 mm / s.

[0059] This can be configured such that, when the lower limit of the pressure drop is reached, the damping force is in the range of 100N to 800N, preferably 200N to 700N, more preferably 400N to 500N, especially 450N, and / or when the upper limit of the pressure drop is reached, the damping force is in the range of 300N to 3000N, preferably 500N to 2000N, more preferably 700N to 1500N, especially 900N.

[0060] Starting from the stationary state of the gas pressure element 4, the damping force preferably increases relatively slowly during normal operation until it reaches the lower limit of the pressure drop, for example, from approximately 350 N when the piston is stationary to approximately 450 N when the piston speed v is 40 mm / s. Then, under constricted conditions, the damping force preferably increases relatively rapidly until it reaches the upper limit of the pressure drop, for example, from approximately 450 N at a piston speed v of 40 mm / s to approximately 900 N at a piston speed v of 50 mm / s. Finally, under overload conditions, the damping force preferably remains substantially constant, for example, maintained at approximately 900 N when the piston speed v is above 50 mm / s.

[0061] As already explained and in Figure 3 As shown in sub-figure a), especially when the two drive couplings 4a, 4b are driven close together, during normal operation of the gas pressure element 4, the valve assembly 10 has an open state in which the overflow passage assembly 9 has a cross-section larger than that in the constricted state and / or smaller than that in the overload state. Furthermore, this also applies to the gas pressure element 4 in… Figure 2 The corresponding static states shown in sub-figures a) and b) refer to the situation where the gas pressure element is not operated and the two drive couplings 4a, 4b are stationary relative to each other, where there is no pressure drop at all. Additionally or alternatively, the valve assembly 10 can be configured to automatically switch from an open state, particularly via a constricted state, to an overload state when the pressure drop increases, especially when the two drive couplings 4a, 4b are driven closer together. In the open state, the overflow channel assembly 9 has a cross-section larger than that in the constricted state and / or smaller than that in the overload state.

[0062] The automatic switching of valve assembly 10 from the open state to the constricted state, and if necessary, further to the overload state, is provided primarily only in the single adjustment direction of gas pressure element 4, particularly in the adjustment direction corresponding to the closing direction of cover 2. However, in principle, in another embodiment not shown here, it is also conceivable that the automatic switching of valve assembly 10 from the open state to the constricted state, and if necessary, further to the overload state, is additionally or alternatively provided in the adjustment direction corresponding to the opening direction of cover 2.

[0063] Furthermore, in the drive assembly 1 shown here, and in this regard preferred, the valve assembly 10 automatically switches from an overload state to a constricted state when the pressure drop is below a predetermined upper limit, and / or automatically switches from a constricted state to an open state when the pressure drop is below a predetermined lower limit. This applies in any case when the two drive couplings 4a, 4b are driven together, but it also applies in particular when the two drive couplings 4a, 4b are driven apart, for example by the optional drive elastic assembly 12 described below.

[0064] Therefore, as Figure 2 As shown in the present embodiment, the gas pressure element 4 here and preferably has a drive elastic component 12, which has at least one first helical spring 13 and / or at least one second helical spring 14. The first helical spring 13 and / or the second helical spring 14 are, in particular, helical compression springs or helical tension springs, which are preferably arranged parallel or coaxially with the cylinder 6. In particular, the first helical spring 13 here radially surrounds the cylinder 6. The second helical spring 14 here is in particular radially surrounded by the cylinder 6.

[0065] At least one first helical spring 13 is preferably used to drive the drive couplings 4a, 4b apart, wherein the first helical spring 13 resists piston movement particularly over the entire range of motion of the piston 8 (i.e., over its entire stroke). When the two drive couplings 4a, 4b are driven together, at least one second helical spring 14 preferably resists piston movement only in the final portion of its range of motion.

[0066] Valve assembly 10 is hereby and preferably designed such that, if necessary, it is supported by drive elastic component 12 so that, under overload conditions, the pressure drop can be reduced, especially rapidly, by increasing the cross-section of overflow channel assembly 9 until it is again below the predetermined upper limit of the pressure drop, causing valve assembly 10 to automatically switch to the narrowing state.

[0067] "Can be reduced" means that when the force introduced into the gas pressure element 4 and driving the drive couplings 4a and 4b together is kept constant or reduced, then at least the pressure drop is reduced. For example, this is the case when the force introduced into the gas pressure element 4 and driving the drive couplings 4a and 4b together is generated solely by the weight of the cover 2. By placing the valve assembly 10 in a constricted state due to the particularly rapid reduction in pressure drop, the damping increases due to the resulting reduction in the cross-section of the overflow channel assembly 9, thereby slowing down the piston movement and the corresponding opposing movement of the two drive couplings 4a and 4b.

[0068] As described, valve assembly 10 can be supported by drive elastic component 12. This means that when the two drive couplings 4a, 4b are driven to come together, the elastic force of drive elastic component 12 resists piston movement, preferably persistently via the first helical spring 13, and especially additionally segmentally via the second helical spring 14. The piston movement, and correspondingly the opposing movement of the two drive couplings 4a, 4b, can thus be additionally slowed, at least within the limited portion of the pivoting movement of cover 2.

[0069] It is also conceivable that, caused by the particularly rapid decrease in pressure drop, valve assembly 10 even temporarily switches to the open state (via a constricted state) because it is also temporarily below the lower limit of the pressure drop, and then switches back to the constricted state, in which the piston movement and the corresponding opposing movement of the two drive couplings 4a, 5b are slowed down due to the reduced cross-section of the overflow channel assembly 9.

[0070] In principle, it is conceivable to perform the above switching process multiple times in order to slow down the closing movement of the cover 2 of the vehicle under overload conditions. The valve assembly 10 then switches to a constriction state with increased damping due to a particularly rapid decrease in pressure drop, and then switches back to an overload state because the pressure drop rises again, in which the damping decreases again. Then, the valve assembly 10 switches back to the constriction state with increased damping due to a renewed, particularly rapid decrease in pressure drop. Then, with each switch back to the constriction state, the piston speed v is further reduced compared to the previous time the valve assembly 10 was in the constriction state, and the pivoting movement of the cover 2 is slowed down.

[0071] To slow down the pivoting movement of the cover 2, it is advantageous, as in this embodiment, that the drive elastic component 12 is designed such that its elastic force increases as the distance between the two drive couplings 4a, 4b relative to each other decreases. Preferably, this is such that during the closing movement of the cover 2, the reduction in the shortest vertical distance between the pivot axis X of the cover 2 and the line of action of the elastic force (the torque applied to the cover 2 is generated by the elastic force) is at least partially, preferably completely, compensated.

[0072] In this way, the spring assembly 12 provides optimal support for the valve assembly 10, preferably over almost the entire pivot range of the cover. In this way, the braking of the closed cover can also be performed more effectively.

[0073] Now, according to Figure 3 The diagram illustrates a particularly preferred embodiment of the gas pressure element 4.

[0074] Therefore, as explained above, the piston 8 has a piston rod 8a and a base 8b fixed to the piston rod 8a, particularly axially fixed relative to it, the base being at least partially sealed relative to the inner surface of the cylinder. The valve assembly 10 here, and preferably, has a valve body 15 movable relative to the base 8b, particularly axially movable relative to the base 8b, the valve body being particularly arranged inside the base 8b, preferably radially inside. Here, and preferably according to... Figure 3 )and Figure 4In sub-figure a), the valve body 15 is radially surrounded by the base 8b in at least a portion of its axial extension, preferably a large portion of its axial extension, more preferably its entire axial extension, at least in its open position (described below), and especially in its switch position (described below). Figure 4 In the variations of sub-figures b) and c), the valve body 15 extends axially outward of the base 8b, here and preferably at least a portion of its axial extension, preferably a large portion of its axial extension, at least in each of its open position, and especially in each of its switch position, which are also described below.

[0075] Here, the overflow channel assembly 9 is constructed between the base 8b and the valve body 15. Here, the valve body 15 is guided here, and preferably along the cylinder axis A, at the base 8b, and especially therein.

[0076] Valve body 15 is hereby, and preferably, adjustable relative to the base 8b of piston 8 to a plurality of switching positions, including: at least one open position ( Figure 3 Sub-figure a), wherein valve assembly 10 has an open state; at least one constricted position ( Figure 3 Sub-figure b), wherein valve assembly 10 has a constricted state; and / or at least one overload position ( Figure 3 Sub-figure c) shows that valve assembly 10 is in an overload state. Therefore, valve body 15 here is in its initial position (the valve body has this initial position when the gas pressure element 4 is stationary) Figure 2 Preferably, the valve body 15 is deflected toward the piston rod 8a by overcoming the elastic force, as described later. Preferably, the valve body 15 may also occupy multiple open positions relative to the base 8b of the piston 8, as described here, wherein the valve assembly 10 is in an open state; multiple constricted positions, wherein the valve assembly 10 is in a constricted state; and / or multiple overload positions, wherein the valve assembly 10 is in an overloaded state. In this case, the valve body 15 can therefore be in multiple positions of the "open position" type, multiple positions of the "constricted position" type, and / or multiple positions of the "overload position" type. Therefore, here, Figure 2 The initial position shown and Figure 3 The positions shown in sub-figure a) are of the "open position" type, that is, the open position in which valve assembly 10 is in the open state.

[0077] The overflow channel assembly 9 now has one or more fluid channels 11 for fluid-technically connecting the two subspaces 7a, 7b. Regardless of whether it is in an overloaded or open state, these fluid channels 11 fluid-technically connect the two subspaces 7a, 7b to each other. For this purpose, the fluid channels 11 extend between the base 8b and the valve body 15. One or more of the fluid channels 11 are provided with or may have constrictions 16, which define a minimum cross-section of the fluid channel 11 that allows for balanced flow. The respective cross-section of at least one constriction 16 or all constrictions 16 and / or the total cross-section of all constrictions 16 varies depending on the switching position of the valve body 15 relative to the base 8b of the piston 8 (overload position, constriction position, open position).

[0078] "Setting or generating" means that a narrowing 16 is always present in the corresponding fluid channel 11, and the cross-section of the narrowing 16 varies according to the switching position of the valve body 15, in such a way that, when the valve body is displaced relative to the base 8b, the radial profile of the narrowing 16 is segmentally formed by different shaped material segments of the valve body 15 according to the switching position of the valve body 15. Alternatively, a fluid channel 11 that is not active at a certain switching position of the valve body 15 (i.e., the fluid channel does not fluid technically connect the two subspaces 7a, 7b to each other at this switching position, and therefore does not have a flow-through narrowing 16) becomes active at other switching positions of the valve body 15, and then fluid technically connects the two subspaces 7a, 7b to each other at this switching position, thereby forming the narrowing 16. Thus, the fluid channel 11 is then "connected," wherein, if necessary, other fluid channels 11 with narrowings 16 of other cross-sections are then "cut off," i.e., no longer active. The latter can be achieved, for example, by providing fluid channels 11 of different lengths on the circumference of the valve body 15, wherein the cross-section of the corresponding narrowing portion 16 of the fluid channel is different, especially in the active state, wherein, depending on the switching position, different fluid channels 11 or different numbers of fluid channels 11 can be traversed by balanced flow.

[0079] The total cross-section here is the sum of all the cross-sections of the various narrow sections 16. The corresponding narrow section 16 (i.e. the part having the corresponding minimum flow-through cross-section of the fluid passage 11) in the embodiment shown here is shifted according to the switching position of the valve body 15, that is, the narrow section 16 is constructed at other parts of the valve body 15 or the base 8b according to the switching position of the valve body 15.

[0080] Here, and preferably, in the valve body 15, grooves 17 are constructed for each fluid passage 11. Here, and preferably, in one or more types of switching positions, particularly in the "narrowed position" and / or "open position" types (i.e., in the narrowed position and / or open position), the narrowing portion 16 of the fluid passage 11 is formed between a corresponding groove section 17a, 17b of the groove 17 and a mating member 18, particularly a sealing ring, at the base 8b. Additionally or alternatively, as in this embodiment, in one type of switching position, particularly in the "overload position" type (i.e., in the overload position), the narrowing portion 16 of the fluid passage 11 is an annular space 19 between the valve body 15 (here, the chamfered material section 20) and the mating member 18 (here, the sealing ring) at the base 8b. In this respect, the annular space 19 is a completely surrounding free space through which fluid can flow.

[0081] The narrowing 16 of the fluid passage 11 is thus formed in each of the switching positions of the valve body 15 in other sections of the valve body 15, such as in the recessed sections 17a, 17b or the chamfered material section 20.

[0082] According to an alternative embodiment not shown here, the fluid passage 11 may also be configured with grooves 17 in the base 8b for each fluid passage 11, wherein, preferably, the narrowing portion 16 of the fluid passage 11 is formed between a corresponding groove section 17a, 17b of the groove 17 and a mating member 18, particularly a sealing ring, at the valve body 15 in one or more types of switching positions, particularly in the "narrowing position" type and / or the "open position" type (i.e., in the narrowing position and / or the open position). In this case, additionally or alternatively, it may be configured such that, in one type of switching position, particularly in the "overload position" type (i.e., in the overload position), the narrowing portion of the fluid passage 11 is an annular space 19 between the base 8b and the mating member 18 at the valve body 15.

[0083] As in Figure 3 As can be most clearly seen in sub-figure a), 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, and subsequently a second groove section 17b with a smaller cross-section and / or a smaller depth and / or width. Here and preferably, the second groove section 17b here leads to a surrounding chamfered or recessed material section 20. Alternatively, not shown here, it may also be configured such that the second groove section 17b leads to a third groove section having a larger cross-section and / or a larger depth and / or width than the first groove section 17a and / or the second groove section 17b.

[0084] Here, and preferably, as described, the valve body 15 is a component provided with grooves 17 to form corresponding fluid channels 11. Accordingly, the chamfered material section 20 is also part of the valve body 15.

[0085] The chamfered material section 20 is a section of the valve body 15 in which the outer surface of the valve body 15 does not extend parallel to the axis of motion of the valve body 15 (which extends coaxially with the cylinder axis A in this case), but rather extends obliquely relative to it. In this chamfered material section 20, the cross-section of the valve body 15 is therefore reduced, that is, not only reduced in a narrower circumferential section as in the groove 17, but also over a larger circumferential area and preferably over the entire circumference. The flow space here is therefore larger than that of the groove 17 when viewed in the circumferential direction. In this way, as... Figure 3 As shown in sub-figure c), the overflow channel assembly 9 achieves a significantly larger flow-through cross-section compared to the groove 17. Preferably, this results in the annular space 19 being constructed between the material segment 20 surrounding the chamfer and the mating member 18 (here, a sealing ring) in the overload position.

[0086] The same effect as the material section 20 surrounding the chamfer can also be achieved using the material section surrounding the recess (not shown).

[0087] In this regard, it is emphasized again that, as a preferred embodiment, the valve body 15 has a corresponding groove 17 and a chamfered material section 20. However, this can also be provided at the base 8b according to another embodiment not shown here, wherein, as described, a corresponding mating member 18 or sealing ring can then be provided at the valve body 15.

[0088] like Figure 3 As shown, and preferably, the first groove section 17a is arranged toward the subspace 7b, in which the fluid has a lower pressure when the two drive couplings 4a, 4b are driven to approach. Specifically, the first groove section 17a opens into the subspace 7b. The second groove section 17b then connects toward the subspace 7a. The subspace 7a is here a subspace where the fluid has a higher pressure when the two drive couplings 4a, 4b are driven to approach.

[0089] The terms “smaller” and “larger” or “lower” and “higher” are always used in reference to each other, that is, for example, “smaller” cross-section is smaller than “larger” cross-section, or “lower” pressure is less than “higher” pressure.

[0090] Figure 3Sub-figures a), b), and c) are described in this order: First, in the open state, the grooved section 17a, together with the mating member 18 or the sealing ring, forms a cross-section through which fluid flows to balance the pressure drop between the two sub-spaces 7a and 7b. If the pressure drop now increases, the valve body 15 is pressed towards the sub-space 7b due to the increased pressure in sub-space 7a, thereby achieving a narrowing state. Then, in the narrowing state, the grooved section 17b, together with the mating member 18 or the sealing ring, forms a cross-section through which fluid flows to balance the pressure drop between the two sub-spaces 7a and 7b. If the pressure drop increases further, the valve body 15 is further pressed towards the sub-space 7b due to the increased pressure in sub-space 7a, thereby achieving an overload state. Then, in the overload state, the chamfered material section 20, together with the mating member 18 or the sealing ring, forms a cross-section that is here annular, which is then through which fluid flows to balance the pressure drop between the two sub-spaces 7a and 7b.

[0091] like Figure 3 and Figure 4 As shown, when the valve body 15 deflects from its initial position (which the valve body has in the static state of the gas pressure element 4), the valve body 15 is subjected to a force. For this purpose, here and preferably, a valve elastic assembly 21 with at least one valve spring 22 is provided, wherein the valve elastic assembly 21 or at least one valve spring 22 works together with the valve body 15 such that the valve body 15 is elastically loaded relative to the base 8b from its initial position, that is, preferably elastically loaded toward at least one of its open positions or initial positions.

[0092] Different variations of valve resilient assembly 21 in Figure 4 The subgraphs a) to c) are shown. Figure 4 The subgraph a) here corresponds to also Figure 3 The variants shown in sub-figures a) to c) differ in the position of at least one valve spring 22 within the valve assembly 10.

[0093] according to Figure 3 or Figure 4 As shown in sub-Figure a), the valve spring 22 (which is here and preferably the only valve spring 22 of the valve elastic assembly 21) is arranged on one side, particularly the end side, of the lower subspace 7b of the valve body 15 facing the cylinder interior space 7. The valve spring 22 is here and preferably supported at one end on the base 8b or piston rod 8a (here, the radially inwardly projecting section 23), and at the other end on the valve body 15 (here, the side of the valve body 15 facing the lower subspace 7b of the cylinder interior space 7, particularly the end side). Here, the valve spring 22 is here and preferably radially surrounded by the base 8b over at least a portion of its axial extension, preferably a large portion of its axial extension, and more preferably its entire axial extension.

[0094] according to Figure 4 In sub-figures b) and c), the axial section 24 of the valve body 15 extends axially from the base 8b into the upper sub-space 7a of the cylinder interior space 7. This section 24 is spaced apart from the base 8b, particularly having a radial extension 25 at its end opposite to the base 8b. This extension forms an axial abutment for the valve spring 22, which is here and preferably the only valve spring 22 of the valve elastic assembly 21. The valve spring 22 is here and preferably arranged on one side of the base 8b facing the upper sub-space 7a of the cylinder interior space 7, particularly on the end side, and / or radially, particularly along its entire axial extension, surrounding the valve body 15. The valve spring 22 is here and preferably supported at one end in the base 8b (here, its end side) and at the other end in the valve body 15 (here, the radial extension 25 of the valve body 15). Here, the valve spring 22 is axially arranged outside the base 8b, preferably on at least a portion of its axial extension, preferably on most of its axial extension, and more preferably on its entire axial extension.

[0095] In principle, the following combination of the above-described variations is also conceivable: the valve resilient assembly 21 has at least two valve springs 22. For example... Figure 3 or Figure 4 As shown in sub-figure a), a valve spring 22 is then arranged on one side of the lower subspace 7b of the valve body 15 facing the cylinder interior space 7, particularly on the end side, and preferably supported at one end on the base 8b or piston rod 8a, particularly at the radially inwardly projecting section 23, and at the other end on the valve body 15, particularly on the side of the lower subspace 7b of the valve body 15 facing the cylinder interior space 7, particularly on the end side. Figure 4 As shown in sub-figures b) or c), another valve spring 22 is then arranged on one side, particularly the end side, of the upper sub-space 7a of the base 8b facing the cylinder interior space 7, and / or radially, particularly over its entire axial extension, around the valve body 15. This other valve spring 22 is preferably supported at one end of the base 8b, particularly its end side, and at the other end of the valve body 15, particularly at the radial extension 25 of the valve body 15.

[0096] The radial extension 25 can be formed in different ways. According to... Figure 4 As shown in sub-figure b), this extension is formed by a screw-on nut 25a, which is screwed onto the valve body 15, particularly at the end. Here, and preferably, the washer 25b is also part of the radial extension 25. The screw-on nut 25a and / or the washer 25b extend into the axial projection of the spring material, particularly the spring wire, of the valve spring 22, so that the valve spring can axially rest against the screw-on nut 25a, or as in this case, against the washer 25b. Figure 4As shown in sub-figure c), the radial extension 25 is formed by the radial expansion of the material of the valve body 15, especially at its end away from the base 8b. The expanded material of the valve body 15 extends into the axial projection of the spring material of the valve spring 22, especially the spring wire, so that the valve spring can axially abut against the expanded material.

[0097] exist Figure 3 or Figure 4 In subgraph a) and also in Figure 4 In sub-figures b) and c), the valve body 15 can be deflected to the left toward the piston rod 8a, and correspondingly, at least in the deflected state, is elastically loaded to the right toward at least one of its open positions by the valve resilient assembly 21. In the static state and normal operation of the gas pressure element 4, the valve assembly 10 is always in the open state. In principle, the valve body 15 can be without elastic force or loaded with elastic force in the open state of the valve assembly 10.

[0098] As described above, in another embodiment not shown here, it is also conceivable, additionally or alternatively, that the described switching process may be performed in the opposite direction. The valve body 15 may then deflect from its initial position (which the valve body has in the static state of the gas pressure element 4) against forces, particularly against the elastic force provided by the valve elastic assembly 21, in the opposite direction (away from the piston rod 8a).

[0099] In any case, and preferably in this way, the corresponding valve spring 22 is compressed according to the pressure drop between the two subspaces 7a, 7b. For this purpose, the elastic characteristic line of the corresponding valve spring 22 is preferably selected such that the valve body 15 occupies a switching position (overload position, constricted position, open position) corresponding to the pressure drop that then exists, depending on the piston speed v. In particular, the elastic characteristic line of the corresponding valve spring 22 is selected such that, depending on the piston speed v, a section of the valve body 15 is positioned opposite to the mating member 18, which corresponds to the switching state to be set (overload state, constricted state, open state), i.e., for example, a chamfered material section 20 in the overload state, a grooved section 17b in the constricted state, and a grooved section 17a in the open state.

[0100] According to another teaching of independent significance, protection is claimed for a drive assembly 1 for a cover 2, particularly a rear cover, for a motor vehicle, which, if necessary, has at least one motor drive device 3, but at least one gas pressure element 4, particularly a gas spring, wherein the gas pressure element 4 has an outwardly sealed cylinder 6 and a piston 8 that travels along the cylinder axis A within the cylinder internal space 7 and divides the cylinder internal space 7 into two subspaces 7a, 7b, wherein the gas pressure element 4 has a first drive coupling 4a connected to the cylinder 6 and a coupling 4a connected to the piston 8. The second drive coupling 4b, wherein the cylinder 6 is filled with fluid, particularly under pressure, wherein the piston 8 has an overflow channel assembly 9 through which a balanced flow is generated between the two subspaces 7a, 7b for piston movement to balance the pressure drop between the two subspaces 7a, 7b, and wherein the piston 8 is associated with a switchable valve assembly 10, which can be placed in different flow states according to the pressure drop between the two subspaces 7a, 7b, the flow states differing in the size of the flow-through cross section of the overflow channel assembly 9. Reference can be made to all descriptions relating to the drive assembly 1 according to the present proposal based on the first teaching.

[0101] According to the teachings, the valve assembly 10 is configured such that, in particular when the two drive couplings are driven to come together, the valve assembly 10 automatically switches from the open state to the constricted state when the pressure drop exceeds a predetermined lower limit, and automatically switches from the constricted state to the closed state when the pressure drop exceeds a predetermined upper limit. In the constricted state, the valve assembly reduces the cross-section of the overflow channel assembly 9 relative to the open state, and in the closed state, the valve assembly reduces the cross-section of the overflow channel assembly 9 relative to the constricted state.

[0102] Preferably, this is done so that the cross-section of the overflow channel assembly 9 is at least largely, preferably completely, closed after the predetermined upper limit of the pressure drop is exceeded, and therefore no longer permeable, or in any case, significantly permeable.

[0103] According to another teaching of equal independent significance, a cover assembly 5 is claimed, having a cover 2, particularly a rear cover, and a proposed drive assembly 1 mating with the cover 2. Reference can be made to all descriptions relating to the drive assembly 1 according to the first and second teachings of this proposal.

[0104] In particular, it is a cover 2 that is pivotable about a pivot axis X, which is substantially horizontally oriented in the assembled state. As mentioned above, it is precisely in this application case that the drive assembly 1 according to the present invention can be used particularly advantageously. This is especially applicable to the case where the speed of the cover 2 increases, as mentioned above. In the cover assembly 5 according to the present invention, such a situation is particularly defined by the failure of the driving force and / or holding force of the drive device 3, and thus the cover 2 is pushed in the closing or opening direction by elastic force and / or by gravity, or by the user manually closing the cover, wherein the resulting switching of the valve assembly 10 to the constricted state (as set according to the first and second teachings) and, if necessary, to the closed state (as set according to the second teaching) resists and, in particular, prevents further adjustment of the cover 2.

Claims

1. A drive assembly for a cover (2) of a motor vehicle, comprising at least one gas pressure element (4), wherein, The gas pressure element (4) has an outwardly sealed cylinder (6) and a piston (8) that travels along the cylinder axis (A) in the cylinder interior space (7) and divides the cylinder interior space (7) into two subspaces (7a, 7b). The gas pressure element (4) has a first drive coupling (4a) connected to the cylinder (6) and a second drive coupling (4b) connected to the piston (8), wherein the cylinder (6) is filled with fluid. The piston (8) has an overflow channel assembly (9) through which a balanced flow is generated between the two subspaces (7a, 7b) in response to piston movement, thereby balancing the pressure drop between the two subspaces (7a, 7b). The piston (8) is equipped with a switchable valve assembly (10), which is capable of being placed in different flow states according to the pressure drop between the two subspaces (7a, 7b), and the flow states differ in terms of the cross-sectional size of the overflow channel assembly (9). The feature is that, starting from a static state in which there is no pressure drop in the gas pressure element (4), in response to the fluid acting on the valve assembly (10) and exceeding a predetermined lower limit of the pressure drop, the valve assembly (10) automatically switches to a narrowing state, in which the valve assembly reduces the cross-section of the overflow channel assembly (9), and in response to the fluid acting on the valve assembly (10) and exceeding a predetermined upper limit of the pressure drop, the valve assembly automatically switches to an overload state, in which the valve assembly increases the cross-section of the overflow channel assembly (9).

2. The driving component according to claim 1, characterized in that, After the predetermined lower limit of the pressure drop is exceeded, and until the predetermined upper limit of the pressure drop is reached, the cross section of the overflow channel assembly (9) remains open or closed.

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

4. The driving component according to claim 3, characterized in that, The lower limit of the pressure drop corresponds to a piston speed (v) in the range of 30 mm / s to 80 mm / s, and / or the upper limit of the pressure drop corresponds to a piston speed (v) in the range of 40 mm / s to 100 mm / s.

5. The driving component according to claim 4, characterized in that, The lower limit of the pressure drop corresponds to a piston speed (v) in the range of 40 mm / s to 60 mm / s, and / or the upper limit of the pressure drop corresponds to a piston speed (v) in the range of 50 mm / s to 80 mm / s.

6. The driving component according to claim 1 or 2, characterized in that, During normal operation of the gas pressure element (4), the valve assembly (10) is in an open state, in which the overflow channel assembly (9) has a cross-section that is larger than that in the constricted state and / or smaller than that in the overload state, and / or when the pressure drop increases, the valve assembly (10) is able to automatically switch from the open state to the overload state, in which the overflow channel assembly (9) has a cross-section that is larger than that in the constricted state and / or smaller than that in the overload state.

7. The driving component according to claim 6, characterized in that, When the pressure drop is below a predetermined upper limit, the valve assembly (10) automatically switches from the overload state to the constricted state, and / or when the pressure drop is below a predetermined lower limit, the valve assembly (10) automatically switches from the constricted state to the open state.

8. The driving component according to claim 1 or 2, characterized in that, The gas pressure element (4) has a drive elastic component (12) having at least one first helical spring (13) and / or at least one second helical spring (14), the first helical spring being arranged radially around the cylinder (6) in parallel or coaxial arrangement, and the second helical spring being arranged radially around the cylinder (6) in parallel or coaxial arrangement.

9. The driving component according to claim 1 or 2, characterized in that, The valve assembly (10) is designed such that when the two drive couplings (4a, 4b) are driven to come together, the pressure drop can be reduced in the overload state until it falls below a predetermined upper limit of the pressure drop again, so that the valve assembly (10) automatically switches to the narrowing state.

10. The driving component according to claim 8, characterized in that, The drive elastic component (12) is designed such that its elastic force increases as the distance between the two drive couplings (4a, 4b) relative to each other decreases.

11. The driving component according to claim 10, characterized in that, The drive elastic component (12) is designed such that its elastic force increases as the distance between the two drive couplings (4a, 4b) relative to each other decreases, so that during the closing movement of the cover (2), it at least partially compensates for the decrease in the shortest vertical distance between the pivot axis (X) of the cover (2) and the line of action of the elastic force, and the torque applied to the cover (2) is generated by the elastic force.

12. The driving component according to claim 6, characterized in that, The piston (8) has a piston rod (8a) and a base (8b) fixed at the piston rod (8a), and the valve assembly (10) has a valve body (15) movable relative to the base (8b), the valve body being arranged within the base (8b), and the overflow channel assembly (9) being constructed between the base (8b) and the valve body (15).

13. The driving component according to claim 12, characterized in that, The valve body (15) is adjustable to a plurality of switching positions relative to the base (8b) of the piston (8), including: at least one open position in which the valve assembly (10) has the open state; at least one constricted position in which the valve assembly (10) has the constricted state; and / or at least one overload position in which the valve assembly (10) has the overload state.

14. The driving component according to claim 13, characterized in that, The overflow channel assembly (9) has one or more fluid channels (11) for fluid-technically connecting the two subspaces (7a, 7b) and extends between the base (8b) and the valve body (15). A narrowing (16) is provided or can be generated in one or more of the fluid channels (11), the narrowing defining a minimum cross-section of the fluid channel (11) that can be traversed by the balanced flow, and the respective cross-section of at least one narrowing (16) or all narrowings (16) and / or the total cross-section of all narrowings (16) varies according to the switching position of the valve body (15) relative to the base (8b) of the piston (8).

15. The driving component according to claim 14, characterized in that, The valve body (15) has grooves (17) for each fluid passage (11).

16. The driving component according to claim 15, characterized in that, In one or more types of switching positions, the narrowing (16) of the fluid channel (11) is formed between the corresponding first groove section (17a) or second groove section (17b) of the groove (17) and the mating member (18) at the base (8b), and / or in one type of switching position, the narrowing (16) of the fluid channel (11) is an annular space (19) between the mating member (18) at the valve body (15) and the base (8b), and / or a groove (17) is constructed in the base (8b) for each fluid channel (11).

17. The driving component according to claim 16, characterized in that, In one or more types of switching positions, the narrowing (16) of the fluid passage (11) is formed between a corresponding first groove section (17a) or second groove section (17b) of the groove (17) and a mating member (18) at the valve body (15), and / or in one type of switching position, the narrowing (16) of the fluid passage (11) is an annular space (19) between the base (8b) and the mating member (18) at the valve body (15).

18. The driving component according to claim 17, 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 a second groove section (17b) with a smaller cross-section and / or a smaller depth and / or width.

19. The driving component according to claim 18, characterized in that, The second groove section (17b) leads to a chamfered or recessed material section (20), or to a third groove section having a larger cross-section and / or a larger depth and / or width than the first groove section and / or the second groove section (17b).

20. The driving component according to claim 19, characterized in that, In the overloaded position, the annular space (19) is constructed between the chamfered or recessed material section (20) and the mating member (18).

21. The driving component according to claim 12, characterized in that, The valve body (15) is force-loaded relative to the base (8b) in at least one of its constricted and overloaded positions.

22. The driving component according to claim 21, characterized in that, A valve spring (22) is arranged on the side of the valve body (15) facing the lower subspace (7b) of the cylinder interior space (7), and is supported at one end on the base (8b) or the piston rod (8a), and at the other end on the valve body (15), and / or the valve spring (22) is arranged on the side of the base (8b) facing the upper subspace (7a) of the cylinder interior space (7) and / or radially surrounding the valve body (15), and is supported at one end on the base (8b), and at the other end on the valve body (15).

23. A drive assembly for a cover (2) of a motor vehicle, comprising at least one gas pressure element (4), wherein, The gas pressure element (4) has an outwardly sealed cylinder (6) and a piston (8) that travels along the cylinder axis (A) in the cylinder interior space (7) and divides the cylinder interior space (7) into two subspaces (7a, 7b). The gas pressure element (4) has a first drive coupling (4a) connected to the cylinder (6) and a second drive coupling (4b) connected to the piston (8), wherein the cylinder (6) is filled with fluid. The piston (8) has an overflow channel assembly (9) through which a balanced flow is generated between the two subspaces (7a, 7b) in response to piston movement, thereby balancing the pressure drop between the two subspaces (7a, 7b). The piston (8) is equipped with a switchable valve assembly (10) that can be placed in different flow states depending on the pressure drop between the two subspaces (7a, 7b), the flow states being different in terms of the cross-sectional size of the overflow channel assembly (9). The feature is that, starting from a static state in which there is no pressure drop in the gas pressure element (4), in response to the fluid acting on the valve assembly (10) and exceeding a predetermined lower limit of the pressure drop, the valve assembly (10) automatically switches from an open state to a narrowed state, in which the valve assembly reduces the cross-section of the overflow channel assembly (9) relative to the open state, and in response to the fluid acting on the valve assembly (10) and exceeding a predetermined upper limit of the pressure drop, the valve assembly automatically switches from the narrowed state to a closed state, in which the valve assembly reduces the cross-section of the overflow channel assembly (9) relative to the narrowed state.

24. A cover assembly having a cover (2) and a drive assembly (1) corresponding to the cover (2) according to any one of claims 1 to 23.

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