Door drive and motor vehicle equipped therewith

Abstract

The invention relates to a door drive comprising a drive motor (6) and a force-transmission element (1) which transmits pulling and / or pushing forces and which extends along a longitudinal axis (L) from a first end (16) to a second end (17), wherein the drive motor (6) engages on the force-transmission element (1) between the first and second end (16, 17) such that the force-transmission element (1) can be displaced relative to the drive motor (6) along the longitudinal axis (L), and the force-transmission element (1) is designed to be flexible on one plane. The invention additionally relates to a motor vehicle equipped with such a door drive.

Description

[0001] Door drive and motor vehicle equipped with it

[0002] Description:

[0003] The invention relates to a door drive comprising a drive motor and a force transmission element that transmits tensile and / or shear forces and extends from a first end along a longitudinal axis to a second end. The drive motor engages the force transmission element between the first and second ends in such a way that the force transmission element is displaceable relative to the drive motor along the longitudinal axis in order to generate tensile or shear forces for driving the door. Furthermore, the invention also relates to a motor vehicle equipped with such a door drive.

[0004] Motor vehicles typically have at least one door hinged to the body. These doors are increasingly being designed autonomously, allowing them to open and close completely without manual intervention. Such a door is also referred to as a "smart door." The reasons for this autonomous design include, on the one hand, increased comfort and safety, but also the prospect of autonomous, driverless vehicles. Without such a smart door, these vehicles would not be able to continue their journey if a passenger leaves the door open after boarding or alighting. Such smart doors are therefore considered one of the prerequisites for fully autonomous driving.

[0005] To make a motor vehicle door autonomous in this sense, in addition to appropriate control devices, appropriate door drives of the type mentioned above are required. These drive motors generate tensile and / or shear forces on the force transmission element when the latter is attached between the door and a suitable fixed point, e.g., on the vehicle body. These tensile and shear forces then cause the desired opening or closing of the door.

[0006] The known embodiments of such door drives are often designed to convert a rotary motion of the drive motor into a translational motion (stroke) by means of the power transmission device in order to push or close the door. Previous embodiments use power transmission elements based on threaded spindles, gear teeth, or cable drives coupled to a rail. An example of such a door drive with a power transmission element in the form of a threaded spindle is disclosed in US 2023 / 0151673A1.

[0007] A disadvantage of these known systems is their complex design, which results in difficulties and high costs during both manufacturing and assembly. Furthermore, threaded spindles and gear teeth can only accommodate small center distances, which limits modularity. Cable drives coupled to a rail also have only limited adaptability to the surrounding system. However, such modularity or adaptability is regularly required, as doors vary depending on the vehicle model, but generally have very little space for additional components.

[0008] Furthermore, to date, only door drives are used which are calibrated once during production or commissioning and which cannot recalibrate themselves. This means that doors on the driver and passenger sides of a vehicle, for example, require different amounts of manual force for an assisted movement, such as when the door is pushed by a person while the drive motor carries out the movement. In addition, the manually required force will also change with increasing wear. Neither of these is desired by the vehicle manufacturer, as every door should "feel" the same in every situation, for example on an incline or on its side, and also over its service life, i.e. the same manual force assistance should be required over its service life. For this to happen, the end positions, e.g.The state of the fully open and fully closed door must be recalibrated over the lifetime, as these can change slightly with wear.

[0009] Furthermore, existing door drives have the difficulty of responding appropriately to so-called failure situations, for example following an accident. If the drive motor is de-energized, it cannot support or release the door movement. Since the translational movement of the power transmission element must be very slow, the drive motor is usually connected via a very high-ratio gearbox, for example with a gear ratio i > 80. The resulting friction results in a self-locking drive. In the failure situation described, manual operation of the door is blocked or extremely difficult, and occupants would be unable to get out of the vehicle, be rescued, or enter it. To counteract this problem, mechanical clutches, such as slip clutches, are installed, which further complicate the system and increase its cost.

[0010] A further disadvantage of existing door drive systems is the unavoidable ingress of dirt. A rail of a coupled cable drive or a threaded spindle as a power transmission element runs, for example, in the area of ​​the driver and passenger side of the vehicle up to the A-pillar. Accordingly, in the area of ​​the conventionally installed door check strap, these are exposed in the gap or transition between the door and the body and are exposed to external weathering and dirt. This can lead to increased wear and premature failure. Encapsulation is only possible to a limited extent, for example by means of a bellows, which only prevents the ingress of dirt, but not the penetration of moisture.

[0011] Finally, a disadvantage of existing door drives is that they always have a power transmission element with a rigid coupling to the drive motor, for example, in the form of threaded spindles and gear teeth that are always positively engaged. Such a rigid coupling poses a significant risk of entrapment if, for example, a person places a hand in the door gap while the door is automatically closing via the door drive. In this case, the components involved will exhibit no or at most minimal deformation, causing the hand to be severely crushed until software can detect the event and intervene.

[0012] The object of the invention is to propose a door drive of the type mentioned at the outset and a motor vehicle equipped therewith, which overcome the disadvantages of the prior art with a simple structural design.

[0013] To achieve the stated object, the invention proposes the design of a door drive according to the features of patent claim 1.

[0014] A motor vehicle equipped with such a door drive is the subject of patent claim 8.

[0015] Advantageous embodiments and further developments of the invention are the subject of the dependent claims.

[0016] The door drive according to the invention is characterized in that the force transmission element is designed to be bendable in at least one plane.

[0017] According to the invention, instead of a rigid force transmission element, a force transmission element is provided that is bendable in one plane. This force transmission element, like an open pull and / or push mechanism, can transmit the drive force of the applied drive motor into pull or push forces, which can be used to open and close a door. The special feature of this pull and / or push mechanism according to the invention, which is provided as a force transmission element and is bendable in at least one plane, is that, despite its bendability in at least one plane, it is suitable not only for transmitting pull forces but also opposing push forces, so that a door can be opened and closed with just one strand.

[0018] For example, a section of a chain capable of withstanding tensile and / or shear loads can be used as a power transmission element within the meaning of the invention. In particular, according to the invention, the power transmission element can be formed by a finite section of a suitably shaped belt, in particular made of elastomeric material, which is partially wrapped around a pulley coupled to the drive motor.

[0019] Such belts have so far been used in particular as traction drives in an endless configuration, with different cross-sectional designs, for example in the form of flat belts, toothed belts, V-belts or V-ribbed belts. A characteristic of such belts is that they are bendable in a plane and can transmit, in particular, high tensile forces. Within the scope of the invention, such a belt is provided as a power transmission element only in the form of a finite section, i.e., one having two ends spaced apart from one another along its longitudinal extent. The configuration of the belt ensures that, in addition to the properties described above, shear forces can also be reliably transmitted.

[0020] According to one proposal of the invention, the belt has a profile cross-section that extends from a belt back facing the pulley and engaging therewith, and the profile body has a plurality of slot-shaped recesses extending transversely to the longitudinal extent of the belt and ending before the belt back, which divide the profile body into a plurality of longitudinally successive profile blocks. The slot-shaped recesses are preferably arranged equidistantly along the longitudinal extent of the belt, thus also producing a sequence of equally sized profile blocks.This configuration and geometry of the belt allows it to be bent not only in one plane across the belt back, but also in the opposite direction, at least until adjacent flanks of the recesses touch each other, creating a surface pressure that prevents further bending in this direction. This makes it possible, according to the invention, to also transmit shear forces via the belt section, so that it can be used as a force transmission element of the door drive according to the invention that is bendable in one plane and thus flexible, transmitting tensile and / or shear forces.

[0021] It is further provided that the belt is guided between the pulley driven by the drive motor and at least one tensioning and deflecting pulley. By arranging at least one tensioning and deflecting pulley, preferably at least two of these tensioning and deflecting pulleys, the belt can be given a desirable pretension by means of the, for example, spring-loaded tensioning pulley, which can be easily and preferably automatically adjusted over the service life and changing operating conditions of the door drive according to the invention. On the other hand, the direction of travel of the force transmission element, which can be bent in the plane, can also be predetermined, for example to give it an arc-shaped travel, which will be explained in more detail below.

[0022] Further design features that promote the transmission of shear forces through the belt arise from the fact that the belt should have a ratio of its thickness to its width of at least in the range of 1:2, whereby a shift towards a thickness to width ratio of 1:1 further increases the transferability of shear forces. However, the transmission of shear forces is only possible via a comparatively short run of such a belt section, whereby the ratio of the thickness of the profile body to the free run length between the first end and the point of application of the drive motor should preferably be in the range of a maximum of 1:12. By incorporating a plurality of slot-shaped recesses ending in front of the belt back, the belt proposed according to the invention is also designed so flexibly that it can be easily adapted to the complex spatial conditions in a door. For example,It is possible to insert an unloaded end of the power transmission element, designed as a section of a belt, into the door and roll it up into a space-saving recess, for example, if this end is fixed to a retaining bolt in the door. Guiding it along a guide rail is also an option.

[0023] For sufficient flexibility and simultaneous limitation of the bendability of the belt used as a power transmission element according to the invention, the recesses can be introduced according to a further proposal of the invention in an approximately V-shaped or wedge-shaped profile body and have a width of 0.1-1 mm, preferably approximately 0.6 mm.

[0024] The design of the slot-shaped recesses with a V-shaped or wedge-shaped arrangement of the lateral boundary walls or flanks when viewed in cross-section has the advantage that the belt inevitably forms a circular arc when subjected to shear loads, with the flanks of a recess coming into contact with one another. The minimum radius of such a circular arc is determined by the geometry and dimensions of the slot-shaped recesses. When the belt is bent over the back of the belt, a surface pressure is created between the adjacent flanks of the individual recesses, which determines the maximum bending of the belt in this bending direction. This significantly reduces the risk of the belt buckling under shear loads compared to a straight belt, since the surface pressure created on the slot-shaped recesses in the direction of the forming circular arc prevents such buckling.The resulting shear load itself prevents an opposite bend across the belt back, because once the belt is curved, the shear force itself generates a force component that promotes the further formation of this circular arc. This design results in a belt that can be bent only to a limited extent across the side of its profile body, into which the recesses are located, but can be bent significantly across its back, particularly when unloaded. This advantageous circular arc alignment can be predetermined and supported by appropriate deflection with at least one deflection pulley in the area of ​​the drive motor.

[0025] The arrangement of the recesses also makes it possible to bend the belt across the back of the belt, i.e., opposite the slotted recesses, and to adjust its flexibility depending on the depth of the recesses. The belt section can thus be deflected or even rolled up to adapt to the specified installation space.

[0026] According to a further proposal of the invention, the slot-shaped recesses have a depth that is at least 40% of the total height of the profile body.

[0027] The belt section can be designed with a smooth surface in the area of ​​its belt back which is in operative connection with the drive motor and can therefore be driven solely by frictional forces.

[0028] According to a further proposal of the invention, the belt can be designed with a toothed profile, particularly in the area of ​​the belt back, so that the belt can be driven in a positive-locking manner via the corresponding toothing and a circumferentially correspondingly toothed pulley. Such a toothing offers the advantage over a V-belt or V-ribbed belt design in that it does not increase the flexural rigidity across the back.

[0029] However, according to a further proposal of the invention, on the side of the profile body facing away from the belt back, into which the recesses are made, the belt section can be provided with a wedge-shaped or wedge-ribbed profile, since this does not increase the flexural rigidity across the belt back, but creates the possibility of driving the belt in a force-locking manner.

[0030] A further proposal of the door drive according to the invention provides that the force transmission element is formed from two sections which can be brought into engagement with one another and which each have a tooth profile of teeth on their mutually facing sides which are spaced apart from one another via a free space between adjacent teeth, wherein a tooth of one section can be inserted into the free space of the other section in a form-fitting manner.

[0031] According to the invention, a motor vehicle with a body and at least one door pivotally mounted on the body about a hinge is also proposed, in which a door drive according to the invention and explained above is provided between the door and the body in order to open and close the door automatically or with assistance by means of the door drive.

[0032] According to one proposal of the invention, a fixed point is provided in the area of ​​the body, for example, adjacent to the hinges used for the pivoting hinges of the doors, to which the first end of the power transmission element is attached. In this case, the drive motor can be arranged in the area of ​​the vehicle door, so that the length of the power transmission element extending beyond the drive motor up to its second end is also arranged and received within the door.

[0033] It goes without saying, however, that this arrangement can also be reversed, i.e. the fixed point for fastening the first end of the force transmission element according to the invention is arranged in the region of the door and the drive motor is fastened on the hinge side in the region of the body. Due to the inventive design of the door drive with a force transmission element that can be bent in one plane, the latter can be guided in the manner already described in a circular arc between the fixed point at the first end of the force transmission element and the point of application of the drive motor, with the center of the arc ideally lying on a hinge axis of at least one hinge of the door in question. Such a door drive then has an identical lever arm for every opening angle of the door. This ensures that the force required to move the door is not dependent on the opening angle of the same and can therefore be used optimally.In this way, a less powerful motor can be used compared to known systems, saving space and costs. Furthermore, the door drive according to the invention consists of only a few components due to the dual function of the flexible power transmission element while only being fixed to a corresponding fixed point on one side. This ensures a smaller installation space requirement in the door.

[0034] In the event of a failure situation, in addition to known mechanical couplings, such as slip clutches, it is possible to implement any intended toothing of the belt back with a small pitch, for example 2M. By carefully selecting an appropriate design element for the pulley driven by the drive motor, the force above which a desired tooth jump occurs can be easily determined. This tooth jump limit force must be higher than the force that must be transmitted during normal operation of the door drive according to the invention. However, as soon as a person initiates tooth jump by applying at least the limit force to the door, the door can be moved manually in the event of a failure, even if the operative connection between the drive motor and the force transmission element is self-locking.

[0035] A similar solution is also possible if, instead of toothing in the area of ​​the belt back, the belt's profile body is designed as a V-belt profile on the side facing away from the belt back. In this case, the wrap angle and the coefficient of friction between the belt and the driving pulley determine the amount of slippage in the entire system. Here, too, the parameters can be configured so that the belt can be caused to slip by manually applying the limit force, allowing the door to be opened manually.

[0036] Finally, the door drive according to the invention can be considered to have a damping effect, which reduces the risk of crushing for a person in the door gap. The additional surface pressure is transferred to the force transmission element according to the invention, for example, a belt, resulting in greater deformation and a more pronounced arc in the path. This reduces the crushing force exerted in the door gap.

[0037] In addition to the previously explained design of the power transmission element using a belt, a design using a section of a chain that can also be bent in one plane is also particularly conceivable. In this case, the drive motor can have a chain pinion that engages the chain in a positive-locking manner.

[0038] The design of the power transmission element from a section of a belt or a chain can be made in one or more parts.

[0039] Further embodiments and details of the invention are explained using exemplary embodiments in the drawings. They show:

[0040] Figure 1 is a schematic plan view of a door drive of a motor vehicle according to the invention;

[0041] Figure 2 shows a further schematic representation of the door drive of a motor vehicle according to the invention;

[0042] Figure 3 shows a further embodiment of a door drive according to the invention; Figures 4a to 4e show various embodiments of a belt of the door drive according to the invention;

[0043] Figure 5 shows a further embodiment of an inventive

[0044] door drive;

[0045] Figure 6 shows a further embodiment of an inventive

[0046] door drive;

[0047] Figure ? a belt of the door drive according to the invention in an enlarged detail view;

[0048] Figure 8a shows a further embodiment of an inventive

[0049] belt;

[0050] Figure 8b shows a further embodiment of an inventive

[0051] belt;

[0052] Figure 9 shows a further embodiment of an inventive

[0053] door drive.

[0054] Figures 1 and 2 show a schematic representation of a door drive of a motor vehicle. The motor vehicle comprises a door 2 pivotably mounted on at least one hinge 4. This door can be, for example, a driver's or passenger door. It can also be a right- or left-side rear door.

[0055] A belt made of an elastomeric rubber material runs as a power transmission element 1 between a fixed point 5, which is provided in the region of a suitable position of the body 3 of the motor vehicle (only indicated in Figure 2), for example the area in which the door check straps are also fastened, and a drive motor 6 arranged inside the door 2 and a pulley 60 driven by it. The belt is fixedly fastened with its first end 16 to the fixed point 5, for example clamped or screwed, and is operatively connected to the drive motor 6 along its longitudinal extent L in the direction of its opposite second end 17. For this purpose, the section of the belt serving as the power transmission element 1 is guided with partial wrapping around the drive motor 6 and its pulley 60. The partial wrapping is positively ensured by a tension pulley 7 and a further deflection pulley 8.

[0056] In this respect, the belt forms a power transmission element in the manner of an open traction and / or thrust drive, ie having only a single strand, which can be flexibly bent in the plane E shown in Figures 1 and 2 and corresponding to the plane of the drawing.

[0057] In the area in which the belt serving as the power transmission element 1 is guided partially looping around the drive motor 6 or its pulley 60, an engagement point is defined via which the drive motor 6 engages the power transmission element 1, such that the power transmission element 1 can be displaced along the longitudinal axis L of the power transmission element 1 when the drive motor 6 and the pulley 60 rotate relative to the drive motor 6. As a result, the length section of this power transmission element 1 extending between the first end 16 at the fixed point 5 and the drive motor 6 can be variably changed by rotating the drive motor 6. If the drive motor 6 is driven clockwise as shown in Figures 1 and 2, the length section of the power transmission element 1 between the fixed point 5 and the drive motor 6 increases, whereby as a result of the rigid clamping of the first end 16 of the power transmission element .1 .at the fixed point 5, a pushing force is generated in the force transmission element 1 between the fixed point 5 and the drive motor 6. If, on the other hand, the drive motor 6 is driven counterclockwise, the length section between the first end 16 and the drive motor 6 is shortened by a corresponding translational movement of the force transmission element 1, and a pulling force is generated within the force transmission element 1 between the fixed point 5 and the drive motor 6. This translational movement and the associated pulling or pushing forces are used to move the door 2, which is pivotally suspended on the hinge 4, relative to the fixed point 5. When pushing forces are generated in the force transmission element 1, the door 2 is moved clockwise, which in the illustrated embodiment corresponds to the opening direction, and when pulling forces are generated, the door 2 is moved counterclockwise, which in the illustrated embodiment corresponds to the closing direction.

[0058] It can also be seen from the illustration according to Figures 1 and 2 that the belt serving as a power transmission element 1 has a continuous belt back 11 on its side facing the drive motor 6 and has, on the opposite side, a plurality of recesses 12 which run transversely to the longitudinal extent L of the belt and end in front of the belt back and which are approximately slit-shaped.

[0059] In addition, the belt used as a power transmission element 1 has a profile cross-section P, as can be seen from the illustration in Figure 7.

[0060] Accordingly, the slot-shaped recesses have a depth T that is at least 40% of the total height H of the profile cross-section P. The recesses 12, viewed in cross-section, can be U-shaped with essentially parallel lateral flanks or V-shaped or wedge-shaped. Furthermore, the ratio of the height H to the width B in the illustrated embodiment is approximately 1:1.

[0061] The slot-shaped recesses 12 are arranged at regular intervals along the longitudinal axis L and divide the profile body adjoining the belt back 11 into a plurality of profile blocks 13 of equal size, which follow one another in the direction of the longitudinal axis L and are each spaced from one another by a slot-shaped recess 12. However, variations in the spacing and size of the recesses 12 provided along the longitudinal axis L are also possible. The recesses 12 provided on the side of the belt section 1 opposite the belt back 11 enable the belt section 1 to be bent over the belt back 11 within the plane E, so that it can wrap around the pulley 60 in the manner shown in Figures 1 and 2.At the same time, the deflection roller 8 ensures, when the belt is guided between it and the pulley 60, that the belt emerging from the door 2 assumes the circular arc-shaped orientation shown in Figures 1 and 2. This circular arc-shaped orientation is supported or predetermined by the fact that the recesses 12 are formed with a width B1 of approximately 0.1-1 mm transverse to the longitudinal extent L of the force transmission element 1, preferably approximately 0.6 mm, wherein the flanks of the recesses 12 adjacent to adjacent profile blocks 13 are preferably arranged approximately V-shaped or wedge-shaped relative to one another.

[0062] When, to open the door 2, thrust forces are generated within the force transmission element 1 by rotating the drive motor 6 with the associated pulley 60 clockwise according to Figure 1, the circular arc-shaped course of the force transmission element 1 within the plane E is formed as a result of the rigid support at the fixed point 5 until the flanks of the recesses 12 abut one another, canceling out the V-shaped or wedge-shaped arrangement to one another, and a surface pressure is generated which transmits these thrust forces between the drive motor 6 and the fixed point 5, whereby the door 2 is opened.

[0063] Conversely, when the drive motor 6 and the pulley 60 attached thereto rotate counterclockwise, a tensile force can be generated between the drive motor 6 and the fixed point 5 within the force transmission element 1, which causes the door 2 to close.

[0064] The circular arc of the force transmission element 1 between the first end 16 fixed at the fixed point 5 and the drive motor 6 is also selected, particularly under applied thrust, such that the force transmission element 1 extends in a circular arc with radius R, as shown in Figure 2, the center point of which lies on a hinge axis of the hinge 4. Thus, the door drive shown has an identical lever arm for every opening angle of the door 2, so that the force required to move the door 2 is not dependent on the opening angle of the door 2 and can therefore be optimally utilized. This force can also be applied by a particularly compact drive motor 6, which can therefore be easily integrated into the door 2.

[0065] The section of a belt provided as the force transmission element 1 in the illustrated embodiment can therefore transmit both the pushing forces required to open the door and the pulling forces required to close the door, while being easily adaptable to the structural conditions due to the given operability in plane E. The length of the force transmission element 1, which is rendered forceless by the drive motor 6 in the direction of the second end 17, is conveyed into a suitable receiving space within the door 2. This is easily possible even in confined spaces due to the flexibility in plane E.

[0066] In addition, the shape of the recesses 12 can be varied in order to optimize the bending of the individual recesses 12 in the area of ​​the pulley 60 during a counter movement over the belt back 11 as a result of the partial wrapping.

[0067] Thus, as can be seen from the illustration according to Figures 1 and 2, the profile blocks 13 and the recesses 12 located between them roll off on the tensioning roller 7 and deflection roller in a non-circular or non-circular manner on the inside of the belt facing away from the belt back 11 due to the opening of the recesses 12 when the belt has the orientation of the recesses 12 running at right angles to the longitudinal axis L as shown in Figure 4a.

[0068] In order to optimise this behaviour, in addition to optimising the position of the tension pulley 7 and deflection pulley 8, the recesses 12 between the profile blocks 13 can also have various other toothing patterns. For example, according to Figure 4b, a step-like angled course of the recess 12 over the width B, an oblique orientation according to Figure 4c, an arrow-shaped arrangement according to Figure 4d or also according to Figure 4e, a toothing with a guide slot 18 along the longitudinal axis L can be provided. Each of these embodiments creates a transition during a counter-movement over the belt back 11, so that the tension pulley 7 and deflection pulley 8 roll more uniformly in this area. In addition, in the embodiments according to Figures 4c and 4d, the diagonal orBy aligning the recesses 12 in an oblique manner, the force can be redirected into a stiffer area of ​​the belt, thereby improving the overall thrust capacity of the belt used as a power transmission element 1.

[0069] In the embodiment according to Figure 4e, it is also possible, due to the additional guide slot 18 running in the longitudinal direction, to replace the tensioning roller 7 and / or deflection roller 8 with a slide rail engaging in the guide slot 18, so that the belt is driven by the pulley 60 and held in its track by the slide rail.

[0070] Further variants of the belt serving as the power transmission element 1 are shown in Figures 8a and 8b. Accordingly, the belt serving as the power transmission element 1 can consist of different segments based on its base material. The different segments can differ, for example, in their hardness in order to optimize the force distribution when transmitting thrust forces.

[0071] According to the exemplary embodiment in Figure 8a, a layered structure is provided in the area of ​​the profile blocks 13 in such a way that two or more different layers are provided, of which a first layer 131, arranged in the inner region of the belt, is made of a softer material than the material of the outer layer 130, which is furthest from the belt back 11. This arrangement is due to the fact that with increasing distance from the neutral axis, the forces arising from deformation due to shear loading also become greater. This force gradient can be compensated for by the illustrated layer structure.

[0072] In the embodiment shown in Figure 8b, the different segmentation varies for each profile block, which is separated from adjacent profile blocks by a recess 12. In the illustrated embodiment, profile blocks 13a are made of a harder material, while profile blocks 13b are made of a softer material. This design would better distribute peak forces caused by greater deformation throughout the entire material of belt 1. However, it is understood that the entire belt could also be made of a uniform material.

[0073] In a manner known per se, tension members are also provided in a manner not shown in detail, which run continuously at least in one plane in the longitudinal direction L and are advantageously placed close to the neutral fiber in the direction of the belt back 11 in order to reliably transmit not only the shear forces but also the tensile forces that occur. If necessary, additional tension members can be located on the inside of the belt, i.e. facing away from the belt back 11, which are interrupted by the recesses 12 in that they were originally provided as continuous and have been segmented by the introduction of the recesses 12. These tension members can increase the hardness and thus the shear capacity of the flanks of the recesses 12. A fabric layer can also be used instead of the tension members.

[0074] Furthermore, the belt section 1, as shown in Figure 7, can have a toothing 111 in the region of its belt back 11 in order to enable a positive engagement of a similarly toothed pulley 60, so that higher drive forces of the drive motor 6 can be transmitted due to the positive engagement achieved.

[0075] To increase power transmission, the opposite inner side of the belt can also be formed with a wedge profile. Furthermore, the belt can also have a segmented belt back 11, in which flanks 110 are provided on both sides of the toothing 111, which also preferably have regular wedge-shaped notches to adapt the maximum back bending to the diameter of the pulley 60 and to counteract lifting off the pulley. It is understood that in this case, the belt is wider than the pulley 60, so that flanks 110 overlap the pulley 60 engaging the toothing 111 on both sides. The width of the toothing 111 preferably corresponds to the width of the pulley 60.

[0076] Furthermore, to ensure a defined end position as shown in Figure 3, the second end 17 of the force transmission element 1, which is opposite the fixed point 5, can be designed with a stop means 10, which forms a positive end stop and serves to absorb extreme loads on the door 2, for example the sudden reaching of a maximum opening angle due to a crash with a cyclist or the like, so that these high forces are not transmitted to the drive motor 6 and mechanical damage is avoided. Instead, the positive end stop 10 engages and transmits the forces to the continuous tension members in the belt serving as the force transmission element 1. In addition to the illustrated design of the end stop 10, other positive embodiments are also possible, which enlarge the cross-section compared to the remaining cross-section of the second end 17.In addition to using the pulley 60 and the tension roller 7 as a counter bearing for the end stop 10, separate stops can also be provided, which can also be provided with damping elements, for example a rubber layer or a complex damping element.

[0077] In a further embodiment, shown in Figure 9, a section 10a of the power transmission element 1 extending to the end 17 of the same is manufactured without recesses 12 as a stop means, so that a high flexural rigidity is achieved in this section 10a due to the enlarged cross-section. This high flexural rigidity means that the power transmission element 1 can only be conveyed by the pulley 60 up to a certain point at which the section 10a enters the space between the pulley 60 and the tensioning roller 7, since deflection or adaptation to the curvature of the pulley 60 entails a high expenditure of force. The increasing force can no longer be overcome above a defined force level and thus causes the desired end stop.The end stop effect can be specifically increased or decreased by changing the position of the tension pulley 7, the position of the deflection pulley 8 and the length of the section 10a.

[0078] The elastic properties of the rubber material also create an end stop damping function.

[0079] The free second end 17 of the belt section, which can be seen, for example, in the illustration according to Figure 2 and which lies opposite the first end 16 fixed at the fixed point 5, is conveyed into or out of the door 2 with a corresponding movement of the drive motor 6. In order to guide the second end 17 and the longitudinal section of the power transmission element 1 adjoining it in the direction of the drive motor in a defined manner in this area, a fixed bearing in the form of a pin or the like (not shown) can be provided within the door 2, so that the free end of the power transmission element 1 is rolled up in a defined manner within the door 2 or forced into a circular arc shape.

[0080] The illustration in Figure 5 shows a further embodiment of the door drive according to the invention, which differs from the previously explained embodiments in that the belt serving as the power transmission element 1 is not a single piece, but rather a two-piece assembly made up of two interengageable sections 1.1, 1.2, which are combined to form a common belt in the longitudinal section between the drive motor 6 and the first end 16 fastened to the fixed point 5 when pulled between the pulley 60 and the deflection roller 8. In the opposite direction towards the second end 17, the belt, after passing between the pulley 60 and the deflection roller 8, is separated into the two sections 1.1, 1.2, which are stored separately within the door 2.

[0081] Both sections 1.1, 1.2 have protruding toothings with teeth 14 on their mutually facing inner sides, which are spaced or separated from each other by a free space 15, wherein the free spaces 15 are dimensioned such that protruding teeth 14 of the other section can be positively received in the individual free spaces 15. When both sections 1.1, 1.2 mesh, the desired circular arc is formed in which the individual teeth 14 mutually support each other.

[0082] In addition, the teeth 14 can be designed with undercuts, as shown in Figure 6, which can prevent a gap from forming between the two sections 1.1, 1.2, for example when large thrust forces occur, thus ensuring the desired circular arc shape at all times.

[0083] By separating the belt into two sections 1.1, 1.2 after entering the door 2, the sections 1.1, 1.2 can be stored separately and individually so that they can be better adapted to complex space conditions in the door 2.

[0084] It is understood that the door drive described above can also be provided with a chain transmitting corresponding tensile and / or shear forces instead of a force transmission element 1 formed from a belt. List of reference symbols:

[0085] 1 power transmission element

[0086] 1.1 Section

[0087] 1.2 Subsection

[0088] 2 doors

[0089] 3 Body

[0090] 4 hinge

[0091] 5 Fixed point

[0092] 6 Drive motor

[0093] 7 Tension pulley

[0094] 8 pulley

[0095] 10 End stop

[0096] Section 10a

[0097] 11 Strap back

[0098] 12 Recess

[0099] 13 profile block

[0100] 13a harder tread block

[0101] 13b softer tread block

[0102] 14 tooth

[0103] 15 free space

[0104] 16 first end

[0105] 17 second end

[0106] 18 Guide slot

[0107] 60 pulley

[0108] 110 flanks

[0109] 111 Gearing

[0110] 130 outer layer

[0111] 131 first layer

[0112] B Width of the belt

[0113] B1 Width of the recess

[0114] E Level

[0115] H Height of the belt L Longitudinal axis

[0116] P profile cross-section

[0117] R Radius

[0118] T Depth of the recesses

Claims

Patent claims:

1. Door drive with a drive motor (6) and a force transmission element (1) which transmits tensile and / or shear forces and which extends from a first end (16) along a longitudinal axis (L) to a second end (17), wherein the drive motor (6) acts on the force transmission element (1) between the first and second ends (16, 17) in such a way that the force transmission element (1) is displaceable relative to the drive motor (6) along the longitudinal axis (L), characterized in that the force transmission element (1) is designed to be bendable in at least one plane (E).

2. Door drive according to claim 1, characterized in that the power transmission element (1) is formed by a section of a belt which is partially guided around a pulley (60) coupled to the drive motor (6).

3. Door drive according to claim 2, characterized in that the belt has a profile cross-section (P) which, starting from a belt back (11) facing the pulley (60) and engaging therewith, has a profile body and the profile body has, in the longitudinal extension of the belt, a plurality of recesses (12) running transversely to the longitudinal extension and ending in front of the belt back (11), which divide the profile body into a plurality of successive profile blocks (13).

4. Door drive according to claim 3, characterized in that the recesses (12) have a width (B1) of 0.1 to 1 mm.

5. Door drive according to one of claims 3 or 4, characterized in that the recesses (12) have a depth (T) which is at least 40% of the total height (H) of the profile cross-section (P).

6. Door drive according to one of claims 2 to 5, characterized in that the belt has a tooth profile (111) and the pulley (60) is circumferentially formed with a toothing corresponding thereto and engages in the tooth profile (111).

7. Door drive according to one of claims 1 to 6, characterized in that the force transmission element (1) is formed from two sections (1.1, 1.2) which can be brought into engagement with one another and which each have a tooth profile of teeth (14) on their mutually facing sides, which are spaced from one another via a free space (15) between adjacent teeth (14), wherein a tooth (14) of one section (1.1, 1.2) can be inserted in a form-fitting manner into the free space (15) of the other section (1.2, 1.1).

8. Motor vehicle with a body (3) and at least one door (2) pivotally mounted on the body (3) about a hinge (4), characterized by a door drive according to one of the preceding claims arranged between the door (2) and the body (3).

9. Motor vehicle according to claim 8, characterized in that in the region of the body (3) a fixed point (5) is provided, to which the first end (16) of the force transmission element (1) is fastened and the drive motor (6) is arranged in the region of the door (2).

10. Motor vehicle according to one of claims 8 or 9, characterized in that the force transmission element (1) extends in a circular arc whose center lies on a hinge axis of the hinge (4).

Images