Drive arrangement of a locking element arrangement

Abstract

Drive arrangement of a locking element arrangement (2) of a motor vehicle (3), wherein the drive arrangement (1) comprises a drive motor (5) and a feed gear (6) downstream of the drive motor (5) for generating linear drive movements along a geometric drive axis (7), wherein the drive motor (5) and the feed gearbox (6) are arranged in a drive train (8) of the drive arrangement (1) and the drive train (8) extends between two mechanical drive connections (9, 10) for transmitting drive movements and wherein the drive arrangement (1) has a brake (11) for braking at least a part of the drive train (8), wherein the brake (11) is designed such that the braking effect of the brake (11) is reduced with an increasing load in the drive train (8), characterized by that the braking effect is reduced by means of a relative rotation of two claw elements (13b, 13c) having claws (13a) of a claw coupling (13) in the drive train (8) as a result of an increasing torque as load.

Description

[0001] The invention relates to a drive arrangement of a closure element arrangement of a motor vehicle with the preamble of claim 1 and a closure element arrangement of a motor vehicle according to claim 14.

[0002] The drive assembly in question is used for the motorized adjustment of any locking element of a motor vehicle. Such locking elements can be, for example, tailgates, trunk lids, engine hoods, cargo floorboards, but also doors, especially sliding doors, of a motor vehicle. In this respect, the term "locking element" is to be understood broadly in this context.

[0003] The known drive arrangement (DE 10 2014 100 125 A1), from which the invention is based, is equipped with a drive motor and a spindle-spindle nut gear downstream of the drive motor. The drive arrangement further comprises a brake for braking the drive train, which enables the closure element to be held in an open position. Furthermore, an overload clutch with two claw-like coupling elements is provided in the drive train, which disconnect the drive train in the event of an overload. In the limit range for an overload, a relative displacement of the two claw-like coupling elements occurs relative to one another. Through their interaction, they act on the brake in such a way that the braking effect of the brake is increased. Consequently, an increasing load in the drive train results in an increase in the braking effect of the brake.

[0004] The disadvantage of this drive arrangement is that in situations where the drive assembly must handle an already high load, it experiences an additional increase in load due to the increasing braking force. This further increases the likelihood of an overload occurring and the drive train disconnecting. This principle means that in order to enable safe operation of the drive assembly even with higher loads on the closure element, relatively powerful and therefore expensive motors must be used, since in addition to the already higher load, for example due to snow pressing on the closure element, an increased braking effect must also be overcome.

[0005] Further drive arrangements with a brake for braking the drive train are known from US 2014 / 0 083 226 A1, US 2010 / 0 192 328 A1, DE 10 2012 108 094 A1, DE 20 2010 015 551 U1, EP 2 284 345 A1 and DE 101 52 697 A1.

[0006] The invention is therefore based on the problem of designing and developing the known drive arrangement in such a way that a drive arrangement is created which can be produced cost-effectively and which functions reliably even when additional loads are applied to the closure element.

[0007] The above problem is solved in a drive arrangement according to the preamble of claim 1 by the features of the characterizing part of claim 1.

[0008] The key consideration is to design the brake in such a way that the braking effect is reduced as the load in the drive train increases. This means that only a lower torque is required from the drive motor at the overload limit, allowing the overall design to be smaller and thus more cost-effective.

[0009] The basis for this consideration is the realization that the holding function for holding the locking element in an open position often has to be ensured precisely in the upper third of the locking element's opening angle. Due to the leverage ratios of the locking element arrangement, this results in the load acting on the drive train for holding the locking element in an open position being generally significantly smaller than the load occurring in the drive train when the locking element is opened from the vehicle lock. This is even more true when an additional load rests on the locking element, such as a snow load.

[0010] This leads to the basic principle of the invention: to design the brake to be load-dependent. With small loads required to implement the holding function, particularly regardless of whether these are initiated by the motor or the spindle, the full braking effect is preferably applied. With increasing transmission torques, the brake reduces the braking effect, for example, when opening the locking element from the vehicle lock. Because the braking effect is reduced in the movement sections of the locking element where a higher load acts on the drive arrangement, smaller and therefore more cost-effective drives can be used, and / or heavier locking elements can be opened and / or closed using the drive arrangement.

[0011] According to claim 2, it is proposed that the braking effect of the brake is reduced during a motorized drive movement to open the closure element arrangement and / or during a manual drive movement to close the closure element arrangement with an increasing load in the drive train. Reducing the braking effect is particularly advantageous in this application, since these two applications—namely, the motorized opening and the manual closing of the closure element—are typically the applications in which overloads occur.

[0012] Additionally or alternatively, according to claim 3, the braking effect of the brake can be reduced in the case of a motor drive movement for closing the closure element arrangement and / or in the case of a manual drive movement for opening the closure element arrangement with an increasing load in the drive train.

[0013] According to claim 4, it is particularly preferred that the load be a torque transmitted by the drive train and / or a force acting externally on the drive connections, particularly axially relative to the drive axle. The brake can be implemented particularly easily in a mechanical manner for both the load case of a transmitted torque and the load case of a force. A combination of these load cases is also possible.

[0014] According to claim 5, it is proposed to reduce the braking effect of the brake continuously, in particular inversely, with the increasing load. This enables a uniform opening and / or closing movement of the closure element by means of the drive arrangement.

[0015] According to claim 6, a predefined limit load is proposed, above which the brake reduces the braking effect with increasing load.

[0016] According to claim 7, the drive assembly can have an overload clutch that disconnects the drive train in the event of an overload. This allows the drive assembly to be effectively protected against overload. The overload clutch is preferably integrated into the brake.

[0017] According to claim 8, after the drive train has been separated by the overload clutch, the brake acts only on one part of the drive train and / or on both parts of the drive train.

[0018] Preferred embodiments of the brake are described in claims 9 and 10. These enable particularly simple assembly of the drive assembly.

[0019] It is proposed that the braking effect be reduced by means of a relative displacement, in particular a relative rotation, of two components in the drive train, in particular two components of the brake in the drive train, as a result of an increasing load. According to claim 11, the relative displacement of the components preferably occurs counter to the spring preload of a spring arrangement, in particular along a relative displacement contour. This makes it possible to achieve the reduction in the braking effect in a particularly simple mechanical manner.

[0020] In a further development of the invention according to claim 12, the feed gear can be designed as a spindle-spindle nut gear. According to claim 13, the brake is preferably arranged between the drive motor and the feed gear in the drive train.

[0021] Furthermore, the above-described object is achieved by a closure element arrangement of a motor vehicle according to claim 14.

[0022] This further teaching is of independent significance. The proposed closure element arrangement achieves the same advantages as those described above in connection with the drive arrangement. Reference is made to all statements regarding the proposed drive arrangement.

[0023] The preferred development of the closure element arrangement according to claim 15 describes a preferred coordination of the brake and the closure element arrangement.

[0024] In the following, the invention is explained in more detail with reference to a drawing which merely illustrates exemplary embodiments. In the drawing, Fig. 1 shows a schematic representation of the rear area of ​​a motor vehicle with a proposed drive arrangement, Fig. 2 a first embodiment of a proposed drive arrangement in a partial longitudinal section, Fig. 3 the embodiment from Fig. 2 in section III with a proposed brake a) at low load and b) at high load, Fig. 4 a second embodiment of a proposed brake a) at low load and b) at high load, Fig. 5 a third embodiment of a proposed brake a) at low load and b) at high load, Fig. 6 an embodiment of a brake which is not the subject of the invention, a) at high pressure load, b) low load and c) at high tensile load.

[0025] The Fig. The drive assembly 1 shown in Figure 1 is associated with a closure element assembly 2 of a motor vehicle 3. The closure element assembly 2 has a closure element 4 configured as a tailgate, which is adjustable by means of the drive assembly 1, in particular between an open position and a closed position.

[0026] In principle, it can be provided that the drive arrangement 1 adjusts the closure element 4 only in a portion of the entire adjustment range of the closure element 4. However, the closure element 4 is preferably adjusted over at least 80%, preferably at least 90%, more preferably at least 95% of the adjustment path from an open position to a closed position and / or from a closed position to an open position. For example, the closure element 4 can be adjusted on the last section of the path into and / or out of a closed position locking the closure element 4 by means of an auxiliary closing drive and / or an auxiliary opening drive via a motor vehicle lock and in particular not via the drive arrangement 1.

[0027] The term "closure element" is to be understood broadly in this context. In this regard, reference may be made to the introductory part of the description. Accordingly, the term "closure element" refers in particular to those components that are assigned to a closure element arrangement 2 of a motor vehicle 3.

[0028] The drive arrangement 1 has, as shown in Fig. 2, a drive motor 5 and a feed gear 6 connected downstream of the drive motor 5 for generating linear drive movements along a geometric drive axis 7. The drive motor 5 and the feed gear 6 are arranged in a drive train 8 assigned to the drive assembly 1, which extends between two mechanical drive connections 9, 10. The drive connections 9, 10 serve here to transmit the drive movement to the closure element 4 and the body of the motor vehicle 3.

[0029] The drive train 8 comprises all force chains through which a force flow is established during motorized and / or manual adjustment. This includes not only all components that transmit drive movements, but also supporting components.

[0030] Furthermore, the drive assembly 1 here has a brake 11. The brake 11 is preferably arranged between the drive motor 5 and the feed gear 6. In the exemplary embodiments, the drive motor 5, the feed gear 6, and the brake 11 are accommodated in a housing 1a of the drive assembly 1.

[0031] According to the proposal, the brake 11 is designed such that the braking effect of the brake 11 is reduced with an increasing load in the drive train 8. Such a design of the brake 11 is particularly advantageous because, due to the characteristic lever arm ratios of a locking element arrangement 2, the holding force of the drive arrangement 1 is often significantly smaller than the force required to open the locking element 4 from a motor vehicle lock, i.e., in particular, from the closed position in the first adjustment section. In this case, the required force is particularly high if, in addition to the locking element 4, a snow load resting on the locking element 4 must also be adjusted.

[0032] This results in the essential advantage of the present invention. Because the brake 11 is designed for load-dependent braking of the drive train 8 in such a way that the braking effect of the brake 11 is reduced with an increasing load in the drive train 8, the brake 11 can preferably brake with full braking effect to hold the closure element 4 in an open position, but with a reduced braking effect when the load increases, in particular when the transmission torque and / or axial force increases, in particular when the closure element 4 is opened from the closed position. This enables the use of smaller drive motors and thus a reduction in the manufacturing and production costs for the drive assembly 1.

[0033] The braking effect of the proposed brake 11 is preferably provided mechanically, in particular by the sliding of friction surfaces 12a, 12b against each other. For this purpose, the brake 11 has at least one pair of friction surfaces 12 with friction surfaces 12a, 12b, which provide the braking effect.

[0034] In the exemplary embodiments and preferably, the braking effect of the brake 11 is reduced during a motorized drive movement to open the closure element arrangement 2 and / or during a manual drive movement to close the closure element arrangement 2 with an increasing load in the drive train 8.

[0035] Additionally or alternatively, it can be provided that the braking effect of the brake 11 is reduced during a motor drive movement to close the closure element arrangement 2 and / or during a manual drive movement to open the closure element arrangement 2 with an increasing load in the drive train 8.

[0036] Preferably, the load is a torque transmitted by the drive train 8 and / or a force acting on the drive train 8, in particular a force acting from the outside on the drive connections 9, 10, in particular axially on the drive axle 7.

[0037] Here, and preferably, the braking effect of brake 11 is reduced continuously, in particular inversely with the increasing load. Instead of such a preferred linear conversion between the increase in load and the reduction in braking effect, a non-linear conversion between the increase in load and the reduction in braking effect can also be set.

[0038] Preferably, a predefined, in particular lower, limit load is provided, above which the brake 11 reduces the braking effect with increasing load. This makes it possible to provide a minimum braking effect for holding the closure element 4 in a predefined load range in which the closure element 4 is securely held by the brake 11. Additionally, a predefined upper limit load can be provided, above which the brake 11 no longer reduces the braking effect and / or at which the drive train 8 is disconnected.

[0039] The reduction of the braking effect of brake 11 here and preferably involves reducing the braking effect to a base value. In this respect, brake 11 is preferably designed to continuously brake at least part of the drive train. However, in an alternative embodiment, the braking effect can also be completely eliminated.

[0040] In particular, the separation of the drive train 8 is preferably effected via an overload clutch 13. This separates the drive train 8 when an overload occurs. The overload clutch 13 is preferably integrated into the brake 11, as in the embodiments of the Fig. 3 and Fig. 4 is the case. However, such an overload clutch 13 can also be provided independently of the brake 11, as is the case in the embodiments of Fig. 5 and Fig. 6 is the case.

[0041] The overload clutch 13 preferably separates the drive train 8 into two parts. After the drive train 8 is separated, the brake 11 preferably acts only on one part of the drive train 8. However, the brake 11 can also act on both parts of the drive train 8 after the drive train 8 is separated.

[0042] In addition, a predefined upper limit load can be defined, above which the braking effect of brake 11 is eliminated and / or no longer reduced. The limit load can be a force and / or a moment.

[0043] In the exemplary embodiments, and preferably, the brake 11 has at least one pair of friction surfaces for generating the braking effect. Here, a friction surface 12a is arranged on a rotatable component 16, 17 of the brake 11, and the friction surface 12b corresponding to this friction surface 12a is arranged in a rotationally fixed manner, in particular on the housing 1a of the drive assembly 1.

[0044] Here, and preferably, the pair of friction surfaces 12 are preloaded against each other by means of a spring arrangement 14. To reduce the braking force, the preload force of the spring arrangement 14 is reduced here, and preferably.

[0045] The following is the example of the Fig. 3 described.

[0046] In the Fig. 3a, the brake 11 is shown at low load. The overload clutch 13 integrated into the brake 11 is here and preferably designed as a claw clutch. The claws 13a of the overload clutch 13 have inclined surfaces, which, as the load increases, as shown in Fig. 3 allow the claws 13a to slide against each other. In this respect, these inclined surfaces form relative displacement contours 15. With increasing load, as in the Fig. As shown in Figure 3b, at least one component 16, here the claw element 13b, is now moved away from another component 17, here the other claw element 13c. This occurs against the preload force of the spring arrangement 18 of the overload clutch 13 - clutch spring arrangement. The components 16, 17 move apart with increasing load, as shown in Figure 3b. Fig. 3. This releases the spring assembly 14 of the brake 11. The friction surface pairs 12 of the brake 11 move apart, and the spring preload of the spring assembly 14 is reduced. The resulting braking effect decreases accordingly.

[0047] The movement apart of the friction surface pairs 12 of the brake 11 is made possible here by the fact that one of the friction surfaces 12b of a friction surface pair 12 is mounted in a rotationally fixed manner but displaceable along the drive axis 7 and a corresponding friction surface 12b of the friction surface pair 12 is displaceable and / or rotatable along the drive axis 7 with the component 16.

[0048] At the time when the relative displacement contours 15 in the embodiment of the Fig. 3 become disengaged, the overload clutch 13 is activated and the drive train 8 is disconnected. Nevertheless, the brake 11 continues to provide a reduced braking effect.

[0049] Here, the load reducing the braking effect is a moment. The relative displacement of the components is preferably a rotation about the direction vector of the load, in particular the load moment, and / or an axial displacement along the direction vector of the load, in particular the load moment. Here, the components 16, 17 move away from each other.

[0050] The embodiment of the Fig. 4 corresponds largely to that of the Fig. 3. In this respect, with regard to structure and functionality, reference is made to the description of the embodiment of the Fig. 3.

[0051] In the embodiment of the Fig. 4, however, the relative displacement contours 15 are designed differently. Instead of a single linear section, they here preferably have two linear sections with different gradients. It is then possible to reduce the braking effect of the brake 11 less on a first section 15a of the relative displacement contours 15 with a lower gradient than on a second section 15b with a higher gradient. The gradient here refers to the gradient of the relative displacement contours 15 relative to a plane orthogonal to the drive axis 7.

[0052] The corresponding relative displacement contours 15 of the two components 16, 17 here and preferably have sections 15a, 15b of the same gradient. These can be of the same length, as in the Fig. 3, or be of different lengths, as shown in the Fig. 4. In the case of sections 15a, 15b of different lengths, preferably at least one section 15a, 15b is longer than the section 15a, 15b corresponding to this section 15a, 15b. Particularly preferably, at least the corresponding sections 15a with a lower gradient are of different lengths. By using sections 15a, 15b of different lengths, the reduction of the braking effect in relation to the load increase over the gradient can be adjusted particularly easily. Preferably, the braking effect is reduced less in relation to a load increase on a first section than on a second section of the relative displacement contour 15.

[0053] The further embodiment of the Fig. Figure 5 shows a similar basic principle. Here, too, the load, depending on which the braking effect of brake 11 is reduced, is a moment. Here, too, the braking effect is reduced mechanically.

[0054] Here, too, depending on the load, two components 16, 17, which are preferably designed as pots, are displaced relative to each other, thereby reducing the braking effect. In the two components 16, 17, the relative displacement contours 15 are designed in the manner of a recess 15c and a nose 15d engaging therein. As in the embodiments of the Fig. 3 and Fig. 4, the relative displacement contours 15 run at an angle to the drive axis 7. They do not intersect it here. Preferably, the angle between the relative displacement contour and the drive axis 7 is between 30° and 60°.

[0055] The two components 16, 17 are here in contrast to the design of the Fig. 3 or Fig. 4, however, cannot be separated by the load when installed. Furthermore, the two components 16, 17 move toward each other here, preferably with increasing load.

[0056] Here and preferably, the relative displacement of the components 16, 17, which reduces the braking effect, is a rotation about and / or an axial displacement along the direction vector of the load, in particular the load moment. In this case, the spring arrangement 14, which here and preferably is accommodated in the pots, is subjected to greater tension, and the friction surface 12a of the rotating components 16, 17 moves away from the, in particular stationary, friction surfaces 12b of the housing 1a. This relative displacement of the components 16, 17 is Fig. 5. Here, both components 16, 17 move towards each other.

[0057] Similar to the example of the Fig. 3 or 4 can also be used in the embodiment of the Fig. 5, a resilient mounting of the friction surfaces 12a in the housing may be provided. In this case, the friction surfaces 12 are preferably designed to be non-rotatable but displaceable along the drive axis 7.

[0058] Here it is preferably the same as in the embodiment of the embodiments of the Fig. 3 and Fig. 4, it is provided that one of the components 16, 17, in particular the components 16, 17, can slide with play along the drive axis 7 on a shaft connection of the drive motor side and / or the feed gear side. In this respect, the brake 11 is preferably mounted in a floating manner between the drive motor 5 and the feed gear 6, as is preferably also the case in the embodiment of the Fig. 6 is the case.

[0059] In the embodiment of the Fig. 6, which is not the subject of the invention, the reduction of the drive force occurs as a function of an axial force as the load and not as a function of a moment as the load. In principle, a combination of the mechanisms of the brakes 11 described in the exemplary embodiments is also possible in such a way that the load for adjusting the braking effect is a combination of an axial force and a transmitted moment.

[0060] Also in the embodiment of the Fig. 6, the components 16, 17 are provided, which are designed to rotate with the drive motor 5. These also have friction surfaces 12a. The corresponding friction surfaces 12b are formed on the housing 1a. Here, too, a relative displacement due to an increasing load on the components 16, 17, which are designed here as disc-like and / or plate-like, reduces the braking effect. Preferably, at least one component 16, 17 is displaced parallel to the direction vector of the load, here the axial tensile force and / or axial compressive force.

[0061] The components 16, 17 are rotationally coupled to the drive motor 5, as in the previously described embodiments. Here, they are preferably mounted on a shaft and are axially displaceable. The bearing spring arrangement 20 serves for mounting. Alternatively, instead of this spring mounting, stops can also be provided, which can be moved from a position, particularly a load-free position (see Fig. 6b) allow axial displacement of components 16, 17 only in one direction along the drive axis. Here, and preferably, a movement of components 16, 17 toward each other.

[0062] The friction surface pairs 12 are preloaded against each other by means of a spring arrangement 14. The spring arrangement 14 is supported on an element 19 that rotates with the components 16, 17 and is preferably mounted axially and rotatably in the housing 1a.

[0063] In the Fig. 6b, the brake 11 is shown in a load-free state. If the drive train 8 is now subjected to an axial pressure load, the feed gear 6 moves towards the drive motor 5, as shown in the Fig. 6a. As a result, component 17 moves toward component 16. Component 16, however, is not moved in the axial direction, as it strikes the housing 1a via the pair of friction surfaces 12.

[0064] The braking force between one pair of friction surfaces 12, here on the right, is reduced by reducing the contact force of the friction surface 12a. The contact force on the other pair of friction surfaces 12, here on the left, preferably remains essentially constant.

[0065] The exertion of a compressive force on the drive train 8 corresponds here and preferably to a motor drive movement for opening the closure element arrangement 2 or a manual drive movement for closing the closure element arrangement 2.

[0066] If a tensile force is exerted on the drive train 8, the same effect as described in connection with the compressive force occurs in reverse. Only the other component 16 is moved towards the component 17, while the component 17 is not moved axially. In this respect, reference is made to the above explanations. This load situation corresponds to a motorized drive movement for closing the closure element and / or a manual drive movement for opening the closure element arrangement 2. In this case, as shown in the Fig. 6c, the braking effect of one pair of friction surfaces, here on the left, is reduced, while here and preferably the braking force of the other pair of friction surfaces, here on the right 12, remains essentially constant.

[0067] This relative displacement of the components 16, 17 for the no-load condition ( Fig. 6b), the condition under pressure load ( Fig. 6a) and the condition under a tensile load ( Fig. 6c) is in the Fig. 6 shown.

[0068] In further embodiments not shown in the figures, only one of the above-mentioned in connection with the Fig. 6. In this case, the braking effect is reduced with increasing load only for one load direction, namely either the compressive force or the tensile force.

[0069] The course of the reduction of the braking effect as a function of the load can be carried out in a simple manner in all four embodiments by the dimensioning of the spring arrangements 14, 18, 20, in particular the spring arrangement 14 to the clutch spring arrangement 18 or to the bearing spring arrangement 20.

[0070] As can be seen from the above explanation of the four embodiments, they have in common that the braking effect is achieved by means of a relative displacement, in particular a relative rotation, at least in the embodiments of the Fig. 3, Fig. 4 and Fig. 5, two components 16, 17 in the drive train 8, in particular two components 16, 17 of the brake 11 in the drive train 8, is reduced as a result of an increasing load. Here, this occurs in each case and preferably by a relative displacement of the components 16, 17 against a spring preload of a spring arrangement 14, 18, in particular along a relative displacement contour 15. The relative displacement contours 15 are here and preferably linear. They can also have several linear sections. Alternatively, they can have an involute contour. Regarding the possible design of the relative displacement contours 15, reference is made to the relevant explanations in connection with the embodiment of the Fig.4. To adjust the reduction in braking effect in relation to the increase in load, the relative displacement contours 15 can be designed accordingly in other configurations. Preferably, due to the geometry of the relative displacement contour 15, the ratio of the change in braking effect of the brake 11 to the change in load in the drive train 8 is greater for a higher load in the drive train than for a lower load.

[0071] In the exemplary embodiments, and preferably, the feed gear 6 is designed as a spindle-spindle nut gear. This allows rotational movements to be converted into linear movements or linear movements into rotational movements in a particularly simple manner.

[0072] A reduction gear 21, which reduces the speed of the drive motor 5 to a lower speed, can also be arranged between the drive motor 5 and the feed gear 6, in particular between the drive motor 5 and the brake 11 and / or the overload clutch 13. This is preferably designed as a planetary gear.

[0073] According to a further teaching, a closure element arrangement 2 of a motor vehicle is claimed, which has a closure element 4 adjustably coupled to the body of the motor vehicle 3 and at least one drive arrangement 1 of the type described above. Preferably, two drive arrangements 1 of the type described above are provided, each arranged on one side of the closure element 2.

[0074] It has proven particularly advantageous if the drive assembly 1 is not self-locking and the brake 11 holds the closure element 4 in intermediate positions when the drive motor 5 is switched off. The closure element 4 is adjustable against the braking effect of the brake 11 for manual adjustment, preferably when the drive motor 5 is switched off.

Claims

[1] Drive arrangement of a closure element arrangement (2) of a motor vehicle (3), wherein the drive arrangement (1) has a drive motor (5) and a feed gear (6) connected downstream of the drive motor (5) for generating linear drive movements along a geometric drive axis (7), wherein the drive motor (5) and the feed gear (6) are arranged in a drive train (8) of the drive arrangement (1) and the drive train (8) extends between two mechanical drive connections (9, 10) for deriving drive movements and wherein the drive arrangement (1) has a brake (11) for braking at least part of the drive train (8), wherein the brake (11) is designed such that with an increasing load in the drive train (8) the braking effect of the brake (11) is reduced, characterized by , that the braking effect is reduced by means of a relative rotation of two claw elements (13b, 13c) of a claw clutch (13) in the drive train (8) having claws (13a) as a result of an increasing torque as a load. [2] Drive arrangement according to claim 1, characterized by that during a motor drive movement to open the closure element arrangement (2) and / or during a manual drive movement to close the closure element arrangement (2) with an increasing load in the drive train (8), the braking effect of the brake (11) is reduced. [3] Drive arrangement according to claim 1 or 2, characterized by that during a motor drive movement to close the closure element arrangement (2) and / or during a manual drive movement to open the closure element arrangement (2) with an increasing load in the drive train (8), the braking effect of the brake (11) is reduced. [4] Drive arrangement according to one of the preceding claims, characterized by that the load is a torque transmitted by the drive train (8) and / or a force acting on the drive train (8), in particular from the outside on the drive connections (9, 10), in particular axial with respect to the drive axle (7). [5] Drive arrangement according to one of the preceding claims, characterized by that the braking effect of the brake (11) is reduced continuously, in particular antiproportionally, with the increasing load. [6] Drive arrangement according to one of the preceding claims, characterized by that a predefined, in particular lower, limit load is provided, above which the brake (11) reduces the braking effect with increasing load, preferably that a predefined, upper limit load is provided, above which the brake (11) no longer reduces the braking effect and / or at which the drive train is disconnected. [7] Drive arrangement according to one of the preceding claims, characterized by that the brake (11) has at least one pair of friction surfaces (12) for generating the braking effect, and that the pair of friction surfaces (12) are prestressed against one another by means of a spring arrangement (14) to achieve the braking effect, preferably that the prestressing force of the spring arrangement (14) is reduced to reduce the braking force. [8] Drive arrangement according to one of the preceding claims, characterized by that the drive arrangement (1), in particular in the drive train (8), has an overload clutch (13) which disconnects the drive train (8) in the event of an overload in the drive train (8), preferably that the overload clutch (13) is integrated into the brake (11). [9] Drive arrangement according to claim 8, characterized bythat after a separation of the drive train (8) by the overload clutch (13), the brake (11) acts only on one part of the drive train (8), and / or that the brake (11) acts on both parts of the drive train (8) after a separation of the drive train (8) by the overload clutch (13). [10] Drive arrangement according to claim 7, characterized by that the drive arrangement (8) has a housing (1a) and that a friction surface (12b) of the friction surface pair (12) is arranged on the housing (1a) or is provided by the housing (1a). [11] Drive arrangement according to one of the preceding claims, characterized bythat the relative displacement of the components (16, 17) takes place counter to the spring preload of a spring arrangement (14, 18), in particular along a relative displacement contour (15), further preferably that due to the geometry of the relative displacement contour (15) the amount of the ratio of the change in braking effect of the brake (11) to the change in load in the drive train (8) is greater for a higher load in the drive train than for a lower load. [12] Drive arrangement according to one of the preceding claims, characterized by that the feed gear (6) is a spindle-spindle nut gear. [13] Drive arrangement according to one of the preceding claims, characterized by that the brake (11) is arranged between the drive motor (5) and the feed gear (6) in the drive train (8). [14] Drive arrangement of a closure element arrangement (2) of a motor vehicle (3), wherein the drive arrangement (1) comprises a drive motor (5) and a feed gear (6) connected downstream of the drive motor (5) for generating linear drive movements along a geometric drive axis (7), wherein the drive motor (5) and the feed gear (6) are arranged in a drive train (8) of the drive arrangement (1) and the drive train (8) extends between two mechanical drive connections (9, 10) for deriving drive movements and wherein the drive arrangement (1) has a brake (11) for braking at least part of the drive train (8), wherein the brake (11) is designed such that with an increasing load in the drive train (8) the braking effect of the brake (11) is reduced, characterized by , that the braking effect is reduced by means of a relative rotation of a first component (16) having a recess (15c) and a second component (17) in the drive train (8) having a nose (15d) engaging in the recess (15c) as a result of an increasing torque as a load. [15] Closure element arrangement of a motor vehicle (3) with a closure element (4) adjustably coupled to the body of the motor vehicle (3) and with at least one drive arrangement (1), preferably two drive arrangements (1), according to one of the preceding claims. [16] Closure element arrangement according to claim 15, characterized by that the drive arrangement (1) is not self-locking and the brake (11) holds the closure element (4) in intermediate positions when the drive motor (5) is switched off, preferably that the closure element (4) is manually adjustable against the braking effect of the brake (11) when the drive motor (5) is switched off.

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