Drive arrangement for a flap of a motor vehicle

Abstract

The invention relates to a drive arrangement for a flap (2) of a motor vehicle (3), comprising a first drive train (5) with a first drive (6) having a body-side and a flap-side first drive connection (7) for an opening movement of the flap (2) and a second drive train (9) for an emergency opening movement of the flap (2), wherein the first drive (6) has a spindle-spindle nut drive (15) with a spindle (16) and spindle nut (17) for performing linear drive movements along a geometric spindle axis (18) between a retracted position and an extended position of the drive, and wherein the spindle nut (17) is axially secured on both sides to a spindle guide tube (19) in which the spindle (16) is axially guided during the linear drive movements, and the spindle guide tube (19) is connected to one of the first drive connections (7,8) and the spindle (16) is axially fixed to the other of the first drive connections (7, 8). It is proposed that the spindle nut (17) remains in a first axial position relative to the spindle guide tube (19) in the axially secured state during an opening movement of the flap (2) and, in the course of an emergency opening movement, performs an axial compensating movement relative to the spindle guide tube (19) from the first axial position to a second axial position relative to the spindle guide tube (19).

Description

The present invention relates to a drive arrangement for a flap of a motor vehicle according to the preamble of claim 1. The known prior art (DE 10 2018 125 800 A1), from which the invention is based, relates to a drive arrangement according to the preamble of claim 1. The drive arrangement in question is used for the externally operated adjustment of any flaps or hatches of a motor vehicle with a body. Such a flap or hatch is, in particular, a front hood, for example, an engine hood or trunk lid, located at the front of the vehicle. It could also be a tailgate, a cargo floor, or even a door of a motor vehicle. In this context, the term "flap or hatch" is to be interpreted broadly. The known drive arrangement comprises two drive trains, each with its own actuator. The actuator of the first drive train, which is coupled to a flap and the body of a motor vehicle via corresponding actuator connections, opens the flap, moving it from a closed to an open position. The first drive train thus fulfills a convenience function by allowing the flap to open automatically when needed. The actuator of the second drive train enables an emergency opening of the flap, moving it from the closed position to a collision position. This can occur, for example, as a result of a collision or in anticipation of one.In the collision position, the flap is tilted open, thus better protecting any occupants involved in an accident. This is because, for example, the flap is positioned at a greater distance from the vehicle components located beneath it and the relatively rigid body, making it more flexible. The second drivetrain therefore fulfills a safety function. The first drive train is coupled to both the flap and the vehicle body. To prevent the emergency opening movement, triggered by the second drive train, from being blocked by the unactuated first drive train, a relative displacement of at least part of the first drive train relative to the flap and / or the vehicle body is required by design. For this reason, the drive assembly features a coupling arrangement with decoupleable coupling elements. In a coupled state, a compensating movement, in which the coupling elements move relative to each other, is prevented. In a decoupled state, the coupling elements can undergo the compensating movement during the emergency opening of the flap, thus achieving the necessary relative displacement. This known drive arrangement has proven highly effective in the past.However, after an emergency opening movement, when the flap is in the collision position, the first drive train is no longer fully functional in the decoupled state of the coupling arrangement. In particular, it may happen that after an emergency opening movement, for example to drive the vehicle into a workshop, the flap cannot be easily returned to the closed position. Such a drive arrangement is also known from DE 10 2023 117 383 A1 , DE 103 25 351 A1 , DE 10 2014 117 008 A1 , DE 10 2019 110 902 A1 , DE 10 2023 124 773 A1 and DE 10 2023 118 954 A1. The challenge lies in improving upon the known state of the art. The invention is based on the problem of designing and further developing the known drive arrangement in such a way that further optimization is achieved with regard to the aforementioned challenge. The above problem is solved by the features of the characterizing part of claim 1. The fundamental principle is that, in a spindle drive with a spindle-spindle nut gearbox as the first drive, during an emergency opening movement the spindle guide tube, which is axially fixed and, in particular, rotationally fixed to the spindle nut during normal operation, is displaced axially relative to the spindle nut without decoupling it from the spindle nut. Thus, the spindle nut remains secured to the spindle guide tube even in the collision position. In this way, a compensating movement, allowing the emergency opening movement, can occur within the first drive when the flap is moved from the closed position to the collision position. Furthermore, the proposed first drive can be easily returned to its original state and the flap closed, for example, by manually pushing the flap, which is in the collision position, towards the closed position.The spindle nut then returns to its initial position within the spindle nut tube, meaning its original axial position relative to the spindle guide tube. Ideally, this process can even occur without manual intervention, simply through actuation of the first drive mechanism itself, as will be explained later. The flap can thus be reliably closed in the collision position, allowing the vehicle to be driven, for example, into a workshop. Specifically, it is proposed that the spindle nut on the spindle guide tube, in the axially secured state, remains in a first axial position relative to the spindle guide tube during an opening movement of the flap, and especially also during a closing movement of the flap in the opposite direction to the opening movement, and in the course of an emergency opening movement, performs an axial compensating movement relative to the spindle guide tube from the first axial position to a second axial position relative to the spindle guide tube. According to the particularly preferred embodiment of claim 2, the spindle nut remains engaged with the spindle during and / or after the compensating movement. Even when the flap is in the collision position, the spindle nut can still be moved axially by rotating the spindle along its geometric axis. Since the spindle nut remains axially secured to the spindle guide tube, the spindle guide tube follows the axial movement of the spindle nut. According to a further embodiment, it is then possible to move the flap from the collision position to the closed position when the first drive is actuated, which is particularly convenient. Claim 3 defines axial stops for the spindle nut within the spindle guide tube, against which the spindle nut comes into contact in the first axial position and in the second axial position, and which limit the axial movement of the spindle nut relative to the spindle guide tube during an emergency opening movement and during a movement opposing this movement. By definition, the spindle nut is axially secured to the spindle guide tube throughout the entire axial range of movement between the first axial position and the second axial position. Claim 4 specifies particularly preferred anti-rotation devices in the first drive which enable linear drive movements during rotation of the spindle in a particularly simple manner. To ensure that the spindle nut is held particularly securely on the spindle guide tube during regular operation of the first drive, a friction-fit, positive-locking, and / or material-locking connection between the spindle nut and the spindle guide tube is optionally provided according to the particularly preferred embodiment of claim 5. This connection is released during an emergency opening movement. However, such a connection can also be omitted, since the weight of the flap always forces the spindle nut into its first axial position within the spindle guide tube. The invention will now be explained in more detail with reference to a drawing that merely illustrates exemplary embodiments. Figure 1 shows a schematic side view of the proposed drive arrangement on a motor vehicle with a body and a flap a) in the closed position, b) in the collision position, and c) in the open position, as well as in d) a first drive of the drive arrangement in the closed position of the flap, and Figure 2 shows an enlarged detail view of the drive from Figure 1d) in the area of ​​the spindle nut a) in the closed position of the flap and b) in the collision position of the flap. Figures 1a), b), and c) schematically illustrate a proposed drive arrangement 1 for a flap 2 of a motor vehicle 3 with a body 4. The drive arrangement 1 is associated with a flap assembly comprising the flap 2. The flap assembly, in turn, is associated with the motor vehicle 3 with the body 4. Here, and preferably, the flap 2 is a hood of the motor vehicle 3. However, the term "flap" 2 is not limited to this, but, as already described above, also includes, for example, a tailgate or a vehicle door of any motor vehicle 3. The drive arrangement 1 comprises a first drive train 5. The first drive train 5 generally enables the flap 2 to be opened, at least automatically, and optionally closed automatically, for example, in response to a user command. When opening, the flap 2 is moved from a closed position, shown in Fig. 1a), to an open position, shown in Fig. 1c). The open position of the flap 2 corresponds, as shown in Fig. 1c), preferably to the maximum open position, in which the flap 2 is fully open relative to the vehicle body 4. When closing, the flap 2 is moved from the open position to the closed position. This can be done automatically and / or manually by a user. The closed position of the flap 2 corresponds, as shown in Fig. 1a), preferably to the main closed position, in which the flap 2 completely closes the vehicle body 4.A motor vehicle lock of the motor vehicle 3, which is not shown in the figures, can secure the flap 2 in the main closed position, whereby the motor vehicle lock is in a main detent position. The first drive train 5 comprises a first drive 6 with at least two first drive connections 7, 8. The first drive 6 can be coupled to the flap 2 via the flap-side first drive connection 7 and to the body 4 of the vehicle 3 via the body-side first drive connection 8. The first drive 6 enables the flap 2 to be opened from the closed position (Fig. 1a) to the open position (Fig. 1c). This allows the general opening principle described above to be achieved by the first drive train 5. The opening movement of the flap 2 can also be effected manually, for example, in the event of a failure of the first drive 6. In addition to the first drive train 5, the drive arrangement 1 has a second drive train 9. The second drive train 9 generally enables collision protection by allowing the flap 2 to be moved into a collision position, for example, as a result of a collision or in anticipation of an accident. The collision position, which is shown in Fig. 1b), differs from the open position of the flap 2. In the collision position, the flap 2 of the vehicle 3 can be inclined forward relative to the vehicle 3, preferably in the opposite direction to the inclination in which the flap 2 is inclined in the open position. This protects those involved in an accident. The second drive train 9 has a second drive 10. The second drive train 9 preferably has a second drive connection on the body side, via which the second drive 10 can be coupled to the body 4 of the motor vehicle 3. The second drive 10 enables an emergency opening movement of the flap 2 from the closed position (Fig. 1a) to the collision position (Fig. 1b). For example, it is possible that in the event of a collision or in anticipation of a collision, the second drive 10 is actuated, whereby, for example, an element of the second drive train 9, such as a plunger, is moved towards the flap 2 and the flap 2 is moved by the element towards the collision position, in particular into the collision position. In this way, the general collision protection principle described above can be achieved by the second drive train 9. The emergency opening movement is different from the opening movement.In particular, the flap 2 is, here and preferably, pivotable in different, especially opposite, directions during the opening movement and the emergency opening movement. In the state of the drive arrangement 1 mounted on the motor vehicle 3, the first drive 6 is coupled to both the body 4 and the flap 2. The second drive 10 is coupled specifically to the body 4. This can be seen, for example, in Figures 1a), b), and c). During the opening movement by the first drive 6, the flap 2 pivots from the closed position to the open position about a pivot point 11. It is possible that during the emergency opening movement, this pivot point 11 can be moved relative to the body 4 by actuating the second drive 10, so that the flap 2 can be moved from the closed position to the collision position. During the emergency opening movement by the second drive 10, the flap 2 pivots from the closed position to the collision position about a further pivot point 12.The first drive 6 is independent of the further bearing point 12, which is located approximately on one side of the flap 2 opposite the second drive train 9. To prevent the emergency opening movement by the second drive 10 from being blocked by the first drive 6, which is not actuated during the emergency opening movement, a compensating movement within the first drive train 5 is necessary. This compensating movement prevents the emergency opening movement from being blocked by the first drive 6 by, for example, a relative displacement of two drive components of the first drive train 5, which will be explained further below. This relative displacement is shown schematically in Fig. 1b) as an upward-pointing arrow. The embodiment shown in the figures, which is preferred in this respect, relates to a drive arrangement 1 for a flap 2 of a motor vehicle 3 with a body 4, wherein the drive arrangement 1 has a first drive train 5, wherein the first drive train 5 has at least a first, in particular springless, drive 6, which is designed as a spindle drive 13, with a body-side first drive connection 8 and a flap-side first drive connection 7, wherein an opening movement of the flap 2 from a closed position to an open position can be effected via the first drive 6.The drive arrangement 1 further comprises a second drive train 9, wherein the second drive train 9 comprises at least a second drive 10, which is designed in particular as a pyrotechnic actuator 14 and / or a pre-tensioned spring, wherein an emergency opening movement of the flap 2 from the closed position to a collision position can be effected via the second drive 10. "Drive springless" here means that the first drive 6 does not have a drive spring assembly with a drive spring that biases the two first drive connections 7, 8 against each other, for example, into the open position. However, according to another embodiment, not shown here, such a drive spring assembly can also be provided. The first drive 6 comprises a spindle-spindle nut drive 15 with a spindle 16 and a spindle nut 17 meshing with it for performing linear drive movements along a geometric spindle axis 18 between a retracted position and an extended position of the drive. The spindle nut 17 is axially secured on both sides to a spindle guide tube 19, in which the spindle 16 is axially guided during the linear drive movements. The spindle guide tube 19 is axially fixed to one of the first drive connections 7, 8, and the spindle 16 is axially fixed to the other of the first drive connections 7, 8. Here, and preferably, the spindle nut 17 is radially inside the spindle guide tube 19, in particular in a receptacle 20 which is axially limited on both sides by the material of the spindle guide tube 19, and is secured axially on both sides. “Axial on both sides” means secured in both directions along the geometric spindle axis 18. "Axially secured" refers to a condition in which movement of the spindle guide tube 19 relative to the spindle 16 can be transmitted to the spindle nut 17, so that the latter follows the movement of the spindle guide tube 19 relative to the spindle 16. For this to occur, the spindle nut 17 does not need to be completely axially immobile relative to the spindle guide tube 19, but rather should, within defined limits, exhibit some axial movement relative to the spindle guide tube 19, which will be explained in more detail below. It is essential that the spindle nut 17 on the spindle guide tube 19 remains in a first axial position relative to the spindle guide tube 19 in the axially secured state during an opening movement of the flap 2, and especially also during a closing movement of the flap 2 in the opposite direction to the opening movement, and in the course of an emergency opening movement performs an axial compensating movement relative to the spindle guide tube 19 from the first axial position to a second axial position relative to the spindle guide tube 19. Furthermore, it is preferably provided that the spindle nut 17, as can be seen in Fig. 2a) and b), is in meshing engagement with the spindle 16 not only in the first axial position relative to the spindle guide tube 19, but also during the compensating movement and / or in the second axial position. A rotation of the spindle 16 can therefore always move the spindle nut 17 axially during the compensating movement and / or in the second axial position, especially when the flap 2 is in its collision position after an emergency opening movement. Furthermore, it is preferably provided that during the opening movement of the flap 2, and especially also during the closing movement of the flap 2, the spindle nut 17, namely when it is in the first axial position relative to the spindle guide tube 19, rests axially fixedly against a first axial stop 21 of the spindle guide tube 19 (Fig. 2a) ). Additionally or alternatively, and preferably, after completion of the emergency opening movement of the flap 2 and / or the compensating movement of the spindle nut 17 relative to the spindle guide tube 19, the spindle nut 17, namely when it is in the second axial position relative to the spindle guide tube 19, rests axially fixed against a second axial stop 22 of the spindle guide tube 19 (Fig. 2b). The second axial stop 22 thus limits, and preferably limits, the compensating movement of the spindle nut 17 relative to the spindle guide tube 19 and thus the emergency opening movement, and defines the position of the flap 2 relative to the body 4 of the motor vehicle 3 in the collision position. The first axial stop 21 of the spindle guide tube 19 is formed here, and preferably as shown in Fig. 2a), by a radially inwardly projecting first material section 23 of the spindle guide tube 19, in particular a first material section 23 of the spindle guide tube 19 produced by rolling or crimping. According to another embodiment not shown here, the first axial stop 21 can alternatively also be formed by a retaining washer 24 or sleeve, which is axially abutted against a radially inwardly projecting material section of the spindle guide tube 19, in particular a section of the spindle guide tube 19 produced by rolling or crimping. The second axial stop 22 of the spindle guide tube 19 can also be formed by a radially inwardly projecting material section of the spindle guide tube 19, in particular a material section of the spindle guide tube 19 produced by crimping. Here, and preferably, the second axial stop 22 is alternatively formed, as shown in Fig. 2b), by a retaining washer 24 or sleeve, which is axially abutted against a radially inwardly projecting second material section 25 of the spindle guide tube 19, here a second material section 25 produced by crimping, in particular an axial end 26, of the spindle guide tube 19. Furthermore, it is preferably provided that the spindle nut 17 is secured against rotation relative to the spindle guide tube 19, specifically in the first axial position relative to the spindle guide tube 19 (Fig. 2a) and / or in the second axial position relative to the spindle guide tube 19 (Fig. 2b)). For this purpose, the spindle nut 17 is preferably in direct, rotationally fixed engagement with the spindle guide tube 19 and axially movable, at least during the emergency opening movement or compensating movement. Additionally or alternatively, and preferably, the spindle guide tube 19, as shown in Figures 1d) and 2a), is secured against rotation relative to a torsion tube 27 of the first drive 6 during linear drive movements. This torsion tube 27 radially surrounds, in particular, the spindle nut 17 and at least axially partially surrounds the spindle guide tube 19. It is rotationally fixed to a first housing segment 28 of the first drive 6, which rotatably supports the spindle 16, and / or to the spindle-side connection of the first drive connections 7, 8. For this purpose, the spindle guide tube 19 is preferably in direct, rotationally fixed engagement with the torsion tube 27, which is axially movable during drive movements. The first drive 6 according to Fig. 1d) preferably comprises a drive housing 29, which includes a first housing part 30 and a second housing part 31 that is telescopically extendable during linear drive movements. The first housing part 30 preferably includes the first housing segment 28, which rotatably holds the spindle 16 and / or aligns it axially with a drive motor 32, and a second housing segment 33, which is axially guided within the second housing part 31. The first housing segment 28 and the second housing segment 33 are connected to each other in a rotationally and axially fixed manner, here by being axially inserted together. The second housing segment 33 is formed here by the torsion tube 27, but can also be a separate housing tube, in particular an inner housing tube. The second housing part 31 is designed here as an outer housing tube. Here, and preferably as also shown in Fig. 1d), an electric drive motor 32 and, in particular, a reduction gear 34 connected downstream of the drive motor 32 are accommodated in the first housing segment 28. The spindle 16 is in turn connected downstream of the reduction gear 34. In operation of the first drive 6, the drive motor 32 drives the spindle 16, here via the reduction gear 34, causing the rotationally secured spindle nut 17 to perform an axial movement along the geometric spindle axis 18. This movement linearly adjusts the two first drive connections 7, 8 between the retracted and extended positions of the drive in order to adjust the flap 2 between the closed position (Fig. 1a) and the open position (Fig. 1c) during regular operation of the first drive 6. Furthermore, and preferably as shown in Fig. 2a), the spindle nut 17 is fixed to the spindle guide tube 19 in the first axial position relative to the spindle guide tube 19 by means of a friction-fit connection. Additionally or alternatively, the spindle nut 17 can also be fixed to the spindle guide tube 19 in the first axial position relative to the spindle guide tube 19 by means of a positive-locking and / or material-locking connection. In this case, a friction-fit connection is in particular a clamping connection, in which the spindle nut 17 is clamped to the spindle guide tube 19, for example, within the spindle guide tube 19, by an axial friction fit. A positive-locking connection is, for example, a snap-fit ​​connection, which is formed, for example, when the spindle nut 17 is axially displaced relative to the spindle guide tube 19. A material-locking connection can be an adhesive bond or a welded joint.In principle, a one-piece connection between the spindle nut 17 and the spindle guide tube 19 can also be provided. However, such a connection can also be omitted in the first axial position relative to the spindle guide tube 19, particularly in the case of a springless first drive 6, so that the spindle nut 17 is freely movable between the first axial position relative to the spindle guide tube 19 and the second axial position relative to the spindle guide tube 19, whereby in this case the weight force of the flap forces the spindle nut 17 into its first axial position in the spindle guide tube 19. The only essential requirement is that the connection can be released when a defined threshold value for an axial force between spindle nut 17 and spindle guide tube 19 is exceeded, in order to allow the compensating movement. Finally, it should be noted that the drive arrangement 1 of the present embodiment is designed for purely active pedestrian protection, i.e., pedestrian protection with a second drive train 9 that enables the flap 2 to be actively moved into the aforementioned collision position (active collision position). In the closed position of the flap 2, the spindle nut 17 is arranged in the first axial position relative to the spindle guide tube 19 and, as a result of a collision or in anticipation of a collision, in particular upon a corresponding control signal generated by an electronic control unit of the motor vehicle 3, when the flap 2 is moved into the aforementioned active collision position, is displaced from the first axial position to the second axial position relative to the spindle guide tube 19. In principle, a purely passive pedestrian protection system or a pedestrian protection system that functions both passively and actively as described above is also conceivable, in which the flap 2 can be passively moved into a collision position (passive collision position). In the closed position of the flap 2, the spindle nut 17 is axially spaced from the first axial position relative to the spindle guide tube 19 and, in particular, is arranged in an intermediate axial position between the first axial position and the second axial position relative to the spindle guide tube 19. As a result of a collision, the flap 2 is then moved from the closed position into a passive collision position by the impact force, i.e., manually and not by a second drive, in which the flap 2 is further retracted into the vehicle body. The passive collision position is therefore located at the same position as the open position.The active collision position is on the opposite side of the closed position of the flap 2. As a result of the collision, when the flap 2 is moved into the previously mentioned passive collision position, the spindle nut 17 is displaced from its axial position, in particular its intermediate axial position, to the first axial position relative to the spindle guide tube 19 by the impact force. In the case of combined active and passive pedestrian protection, which thus combines both of the aforementioned variants, it can also be provided that the spindle nut 17, when the flap 2 is in the closed position, is arranged in the aforementioned intermediate position, so that in the event of a collision the spindle nut is moved either by the impact force, i.e., manually, into the first axial position, and thus the flap 2 into the passive collision position, or by the second drive 10 into the second axial position, and accordingly the flap 2 into the active collision position. A drive arrangement 1 for a flap 2 of a motor vehicle 3 with a body 4 is then provided, wherein the drive arrangement 1 has a first drive train 5, wherein the first drive train 5 has at least one first drive 6, which is designed as a spindle drive 13, with a body-side first drive connection 8 and a flap-side first drive connection 7.wherein an opening movement of the flap 2 from a closed position to an open position can be effected via the first drive 6, wherein the drive arrangement 1 has a second drive train 9, wherein the second drive train 9 has at least a second drive 10, which is designed in particular as a pyrotechnic actuator 14 and / or a pre-tensioned spring, wherein either a first emergency opening movement of the flap 2 in the direction of the opening movement from the closed position to a first collision position (active collision position) can be effected via the second drive 10, or a second emergency opening movement of the flap 2 in the opposite direction to the opening movement from the closed position to a second collision position (passive collision position) can be effected manually, in particular by an impact force,wherein the first drive 6 comprises a spindle-spindle nut drive 15 with a spindle 16 and a spindle nut 17 meshing with it for performing linear drive movements along a geometric spindle axis 18 between a retracted position and an extended position of the drive, and wherein the spindle nut 17 is axially secured on both sides to a spindle guide tube 19 in which the spindle 16 is axially guided during the linear drive movements, and the spindle guide tube 19 is axially fixed to one of the first drive connections 7, 8 and the spindle 16 is axially fixed to the other of the first drive connections 7, 8. It is essential thatthat the spindle nut 17, when axially secured to the spindle guide tube 19, remains in a defined axial position relative to the spindle guide tube 19 during an opening movement of the flap 2, and during an emergency opening movement, performs an axial compensating movement relative to the spindle guide tube 19 from the defined axial position to another axial position relative to the spindle guide tube 19. The "defined axial position" in which the spindle nut 17 remains during the opening movement of the flap 2 is an intermediate position between the first axial position and the second axial position described above. The "other axial position" to which the spindle nut 17 is moved during the axial compensating movement is then the second axial position described above during the first emergency opening movement and the first axial position described above during the second emergency opening movement. In a proposed drive arrangement 1 designed for purely passive pedestrian protection, the aforementioned second drive train is specifically omitted. The drive arrangement 1 is then provided for a flap 2 of a motor vehicle 3 with a body 4, wherein the drive arrangement 1 has a first drive train 5, the first drive train 5 comprising at least a first drive 6, designed as a spindle drive 13, with a body-side first drive connection 8 and a flap-side first drive connection 7, wherein an opening movement of the flap 2 from a closed position to an open position can be effected via the first drive 6, and wherein an emergency opening movement of the flap 2 from the closed position opposite to the opening movement to a collision position can be effected.wherein the first drive 6 comprises a spindle-spindle nut drive 15 with a spindle 16 and a spindle nut 17 meshing with it for performing linear drive movements along a geometric spindle axis 18 between a retracted position and an extended position of the drive, and wherein the spindle nut 17 is axially secured on both sides to a spindle guide tube 19 in which the spindle 16 is axially guided during the linear drive movements, and the spindle guide tube 19 is axially fixed to one of the first drive connections 7, 8 and the spindle 16 is axially fixed to the other of the first drive connections 7, 8. It is essential thatthat the spindle nut 17, when axially secured to the spindle guide tube 19, remains in a defined axial position relative to the spindle guide tube 19 during an opening movement of the flap 2, and, during an emergency opening movement, performs an axial compensating movement relative to the spindle guide tube 19 from the defined axial position to another axial position relative to the spindle guide tube 19. The "defined axial position" in which the spindle nut 17 remains during the opening movement of the flap 2 is either an intermediate position between the first axial position and the second axial position mentioned above, or the second axial position mentioned above. The "other axial position" to which the spindle nut 17 is moved during the axial compensating movement is then, in particular, the first axial position mentioned above. Reference may be made to all details concerning the proposed drive arrangement according to the first teaching, which is illustrated in the exemplary embodiment.

Claims

Drive arrangement for a flap (2) of a motor vehicle (3) with a body (4), wherein the drive arrangement (1) comprises a first drive train (5), wherein the first drive train (5) comprises at least one first drive (6), which is designed as a spindle drive (13), with a body-side first drive connection (8) and a flap-side first drive connection (7), wherein an opening movement of the flap (2) from a closed position to an open position can be effected via the first drive (6), wherein the drive arrangement (1) comprises a second drive train (9), wherein the second drive train (9) comprises at least one second drive (10), which is designed in particular as a pyrotechnic actuator (14) and / or a pre-tensioned spring, wherein an emergency opening movement of the flap (2) from the closed position to a collision position can be effected via the second drive (10).wherein the first drive (6) comprises a spindle-spindle nut drive (15) with a spindle (16) and a spindle nut (17) in meshing engagement with it for performing linear drive movements along a geometric spindle axis (18) between a retracted position and an extended position of the drive, and wherein the spindle nut (17) is axially secured on both sides to a spindle guide tube (19) in which the spindle (16) is axially guided during the linear drive movements, and the spindle guide tube (19) is axially fixed to one of the first drive connections (7, 8) and the spindle (16) to the other of the first drive connections (7, 8), characterized in thatthat the spindle nut (17) on the spindle guide tube (19) remains in a first axially secured state during an opening movement of the flap (2) in a first axial position relative to the spindle guide tube (19) and, in the course of an emergency opening movement, performs an axial compensating movement relative to the spindle guide tube (19) from the first axial position to a second axial position relative to the spindle guide tube (19). Drive arrangement according to claim 1, characterized in that the spindle nut (17) is in meshing engagement with the spindle (16) during the compensating movement and / or in the second axial position. Drive arrangement according to claim 1 or 2, characterized in that during the opening movement of the flap (2), and in particular also during the closing movement of the flap (2), the spindle nut (17) rests axially fixedly against a first axial stop (21) of the spindle guide tube (19) and / or that after completion of the emergency opening movement of the flap (2) and / or the compensating movement of the spindle nut (17) relative to the spindle guide tube (19), the spindle nut (17) rests axially fixedly against a second axial stop (22) of the spindle guide tube (19). Drive arrangement according to one of the preceding claims, characterized in that the spindle nut (17) is secured against rotation in the first axial position relative to the spindle guide tube (19) and / or in the second axial position relative to the spindle guide tube (19), and / or that the spindle guide tube (19) is secured against rotation during the linear drive movements relative to a torsion tube (27) of the first drive (6), which in particular radially surrounds the spindle nut (17) and at least axially sectionally the spindle guide tube (19) and which is rotationally fixed to a housing segment of the first drive (6) rotatably supporting the spindle (16) and / or to the spindle-side of the first drive connections (7, 8). Drive arrangement according to one of the preceding claims, characterized in that the spindle nut (17) is fixed in the first axial position relative to the spindle guide tube (19) on the spindle guide tube (19) via a force-locking and / or form-locking and / or material-locking connection and that the connection is releasable when a defined threshold value for an axial force between spindle nut (17) and spindle guide tube (19) is exceeded.

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