DE102018115430A1 - Drive unit for a door or flap of a motor vehicle - Google Patents

Abstract

The invention relates to a drive unit 1 for a door 10 or flap of a motor vehicle 20 for motorized pivoting of the door 10 or flap, the drive unit 1 being an electric motor 4, a power transmission element 3 which can be rotated by the electric motor 4, and an elongated gear element 2, which can be moved relative to the power transmission element 3, wherein the drive unit 1 is set up in such a way that, through an interaction of the power transmission element 3 with the gear element 2, a rotation of the power transmission element 3 into a translational movement 5 of the gear element 2 for a motorized pivoting of the door 10 or flap can be converted. A cover device 6, 7, 8, 9, 11, 12, 13, 14 for the transmission element 2 is provided, which can generate a displaceable access area 15 for the transmission element 3 for the force transmission element 3. It is thus made possible that the friction and wear of the power transmission element and the gear element can be reduced without significantly increasing the space requirement for the covering device.

Description

The invention relates to a drive unit for a door or flap of a motor vehicle for motorized pivoting of the door or flap, the drive unit comprising an electric motor, a power transmission element that can be rotated by the electric motor, and an elongated gear element that can be moved relative to the power transmission element , The drive unit is set up in such a way that a rotation of the force transmission element can be converted into a translational movement of the transmission element for motorized pivoting of the door or flap by an interaction of the force transmission element with the transmission element.

The publication DE 10 2008 026 040 A1 discloses a device for predominantly motorized adjustment of a motor vehicle door. In the DE 10 2008 026 040 A1 shows how an elongated transmission element in the form of a transmission element is driven by a motor via a gear wheel as a force transmission element for carrying out a translational movement. Such a transmission element or transmission element is therefore generally greased in the interaction area with the force transmission element. As can be seen, the element between the motor vehicle door and the motor vehicle body is freely exposed to the environmental influences when the motor vehicle door is opened or closed. When the element is greased, a greased area is also exposed to the environment, which often causes dust to accumulate and adhere. But even if not greased, such a transmission element or transmission element becomes dirty over time. Increased friction and wear in the system are often observed due to the contamination and / or the adherence of dust.

The aforementioned features known from the prior art can be combined individually or in any combination with one of the objects and embodiments according to the invention described below.

It is an object of the invention to provide a further developed drive unit for a door or flap of a motor vehicle for motorized pivoting of the door or flap.

A drive unit for a door or flap of a motor vehicle for motorized pivoting of the door or flap according to claim 1 serves to achieve the object. Advantageous embodiments result from the subclaims.

To achieve the object, a drive unit for a door or flap of a motor vehicle for motorized pivoting of the door or flap is provided, the drive unit being an electric motor, a power transmission element that can be rotated by the electric motor, and an elongated gear element that is relative to the power transmission element can be moved includes. The drive unit is set up in such a way that an interaction of the force transmission element with the transmission element can convert a rotation of the force transmission element into a translational movement of the transmission element for motorized pivoting of the door or flap.

According to the invention, a cover device is provided for the transmission element, which can generate a displaceable access area to the transmission element for the force transmission element. It is made possible in this way that the friction and wear of the power transmission element and the gear element can be reduced without significantly increasing the space requirement for the covering device.

In particular, the cover device is closed and / or covers the gear element to the surroundings.

The elongated extension of the gear element is oriented in a longitudinal direction. The movable access area can be moved in the longitudinal direction. The longitudinal direction is oriented parallel to the translation movement or to the direction of the translation movement. A translation movement can take place forward or backward along a translation axis.

The engagement area of the gear element, which interacts with the force transmission element, extends in the longitudinal direction. The engagement region has an engagement side which faces the force transmission element. Two lateral sides of the gear element extend in the longitudinal direction perpendicular to the engagement side.

Depending on the position of the transmission element relative to the force transmission element in the longitudinal direction, a different area of the engagement area of the transmission element comes into engagement with the force transmission element.

Due to the displaceable access area, the force transmission element can always interact and / or remain in engagement with the transmission element, that is to say also during a relative translational movement between the force transmission element and the transmission element.

Depending on the position of the gear element relative to the power transmission element in the longitudinal direction, different areas of the gear element are located within the access area and outside the access area.

The cover device ensures that those areas of the engagement area of the gear element which are located outside the access area are closed and / or covered directly by the cover device.

That area of the engagement area of the gear element which is located within the access area is preferably protected from environmental influences by a housing of the force transmission element.

An access area means an area or section of the gear element that is specifically left blank by the covering device, that is to say is not covered, in order to enable the force transmission element to interact with the gear element, i.e. direct engagement of the power transmission element with the transmission element.

The covering device can advantageously comprise a covering element, in particular a belt, preferably a flat belt. A displaceable access area with simultaneous covering of the gear element outside the access area is made possible in this way.

It is conceivable that the drive unit is set up in such a way that the cover element moves outside the access area together with the transmission element relative to the force transmission element. The area of the cover element outside the access area therefore behaves in a manner fixed in terms of movement relative to the gear element, even when the door or flap is opened or closed.

The flat belt cannot move away from the engagement area, e.g. a toothing of a tooth profile, are damaged because the flat belt and the engagement area move together. Furthermore, dirt and dust can thereby be warded off particularly effectively, in particular at the interfaces to adjacent covers of the cover device which are firmly fixed to the gear element. A fixation at one end or at both ends of the cover element preferably serves for the movement-fixed arrangement of the cover element outside the access area. The cover element preferably lies on the gear element outside the access area, preferably on the engagement side.

The drive unit can advantageously be set up in such a way that the cover element moves within the access area relative to the gear element, in particular relatively in the longitudinal direction. The cover element can thus be guided around the force transmission element when the door or flap is pivoted and the gear element moves translationally relative to the force transmission element.

In particular, the drive unit is set up in such a way that the cover element only partially moves within the access area relative to the gear element and / or the cover element is guided around the power transmission element such that only a partial section of the cover element moves within the access area relative to the gear element that is not parallel runs in the longitudinal direction.

In particular, the access area lies between two ends of the cover element in the longitudinal direction.

The cover element can advantageously be arranged on an engagement side of the gear element. The interaction of the force transmission element with the transmission element can take place on the engagement side. This is the interaction by means of which a rotation of the force transmission element can be converted into a translational movement of the gear element for motorized pivoting of the door or flap. Increased friction and wear due to dirt and dust accumulation can thus be countered particularly effectively.

Advantageously, the cover element can rest directly and / or loosely on the engagement side of the gear element outside the access area. The engagement area of the gear element, which is designed for direct interaction with the force transmission element, can thus be covered particularly reliably and easily.

A particularly simply constructed cover device that can be implemented with little effort, but which particularly effectively protects the engagement area from protection and dust, can be realized in this way.

In particular, the cover element lies directly and / or loosely on the engagement area, specifically on its engagement side. Preferably, the cover element lies outside the access area only on the engaging side and / or covers only the engaging side. A special one simply constructed cover device can be obtained.

It is also conceivable that the cover element is fixedly attached to the gear element in one end region or two opposite end regions, in particular by means of a fixation by screws. The end region or the opposite end regions in the longitudinal direction of the gear element are meant here. In this way it can be reliably ensured that there is a common movement of the cover element with the gear element outside the access area. In particular, the engagement area of the gear element extends, e.g. a tooth profile, in the end region or between one end region to the opposite end region of the gear element.

In the context of the invention, the gear element can comprise an engagement area which is designed for direct interaction with the force transmission element, and / or the covering device covers the engagement area of the gear element in a closed manner to the surroundings. A compact cover device with a small space requirement can be provided in this way, which protects the gear element against dirt and dust even when the door or flap is pivoted. Parts of the gear element that do not belong to the engagement area can remain free, i.e. not be covered. These parts of the gear element are exposed to the environment when the door or flap is pivoted.

Furthermore, it is conceivable that the engagement area has a tooth profile or a thread. The gear element is advantageously a toothed rack, a worm shaft or a threaded spindle. In one embodiment, the force transmission element is a gear wheel, a pinion, a worm wheel or a spindle nut. In one embodiment, the gear element is a cable pull and / or the force transmission element is a drive roller for the cable pull. These embodiments enable a particularly reliable conversion of a rotational movement into a translatory movement.

If the engagement region is a tooth profile, the teeth point to the engagement side and / or the lateral sides extend on both sides of the tooth profile in the longitudinal direction perpendicular to the engagement side.

In particular, an axis of rotation of the force transmission element is perpendicular to the longitudinal direction. A compact structure can be obtained in this way.

The drive unit is advantageously set up in such a way that the access area moves together with the force transmission element relative to the transmission element when the door or flap is pivoted. Moving takes place in the longitudinal direction. In this way, the force transmission element can remain particularly reliably and permanently in engagement with the transmission element during a relative translation movement between the force transmission element and the transmission element.

The power transmission element is advantageously arranged between the cover element and the gear element, in particular on the engagement side of the gear element. Disruption of the interaction between the power transmission element and the transmission element by the cover element can be avoided in this way.

The cover element advantageously extends within the access area around the force transmission element, preferably in an arcuate, V-shaped or U-shaped manner. In this way, the force transmission element and the transmission element can interact with one another within the access area without being impaired by the cover element.

It is conceivable that the cover device comprises a lateral cover or two lateral covers for covering the gear element outside the access area and / or within the access area, in particular for covering the engagement area of the gear element laterally.

By providing a divided cover device with separate components for different sides, that is to say the engagement side and laterally thereof, a cover device which is of particularly simple construction but is very effective and durable can be obtained.

The lateral cover or the two lateral covers advantageously protrude on the engagement side of the engagement region of the gear element, preferably by the amount of the thickness of the cover element. An edge of a cover can thereby be flush with the surface of the cover element on the engagement side.

The cover element preferably adjoins the lateral cover or the two lateral covers, in particular directly. The cover element therefore meets the one or two lateral covers transversely to the longitudinal direction, so that an interface extending in the longitudinal direction is created or two such interfaces are created. The cover element thus creates a closed cover together with the lateral cover or the lateral covers.

In particular, the cover element is flush to the outside with the lateral cover or the two lateral covers, i.e. the lateral cover or the lateral covers predominantly do not protrude from the cover element transversely to the longitudinal direction. This avoids a step at which dirt and dust can accumulate, which could lead to increased penetration into the engagement area of the gear element.

In particular, when viewed in cross section, the covering device completely surrounds the engagement area. In particular, a lateral cover ends in the opposite direction to the engagement side beyond the engagement area on the lateral surface of the gear element, so that the engagement area is completely covered laterally.

If two lateral covers are provided, the cover element is arranged in particular centrally between the two lateral covers. The cross-section of the cover element preferably forms a right angle with the lateral cover or with both lateral covers, i.e. a U shape.

The lateral cover can advantageously have a phase, preferably with a 45 ° phase angle. The phase preferably adjoins the cover element. The phase thus forms a longitudinally extending interface with the cover element. A self-centering effect for the cover element can thus be generated with little effort. Self-centering counteracts gap formation at the interface. The resulting v-shaped recess is negligible with regard to the accumulation of dirt or dust, in contrast to a step, compared to the increased sealing effect due to self-centering.

Advantageously, the lateral cover or the two lateral covers can be firmly attached to the gear element and / or strip-shaped. Lateral protection of the engagement area against dirt and dust without a relative movement between the lateral cover and the gear element can be achieved in this way. The permeability of the interface between the lateral cover and an adjacent, resting area of the cover element outside the access area can be reduced without additional sealing measures. In particular, a cover extends at least over the entire extent of the engagement area in the longitudinal direction.

In the context of the invention, the lateral cover can be a strip, preferably made of plastic. In particular, the lateral cover does not allow excessive bending or bending. The gear element is preferably made of metal.

The cover element can be made of an elastic material or material that allows deflection via at least one deflection element. The cover element can be designed as a belt or flat belt. The cover device can thus be produced with particularly little effort.

Within the scope of the invention, at least one deflection element can be provided for deflecting the cover element for generating the access area. A movable access area can thus be provided with particularly little effort and with a particularly small space requirement. The deflection element can advantageously be designed such that it guides the cover element. A particularly reliable functioning of the cover device can be ensured in this way.

Advantageously, a housing of the force transmission element can provide protection of the engagement side of the engagement area within the access area instead of the cover element. In particular, the at least one deflection element is fixedly connected to the housing for the force transmission element or is rotatably mounted thereon.

In the context of the invention, the deflecting element can be a deflecting roller or a pin, preferably made of plastic. As a result, the cover element can be guided around the force transmission element in a particularly simple and reliable manner.

The cover element can preferably have the same width as the gear element, preferably the same width as the engagement area. The width is measured parallel to the engagement side, transverse to the longitudinal direction. A particularly simple construction of the cover device can be achieved in this way.

At least two, three or exactly four deflection elements can advantageously be provided in order to guide the cover element around the force transmission element within the access area. The cover element can be deflected by its deflection on the engagement side of the engagement region and by two deflection elements are returned to the gear element in order to create a movable access area. With three deflecting elements, a triangular access area can be created, from which the cover element can rest on the engagement side of the engagement area in the longitudinal direction on the front and rear side. Exactly four deflection elements enable the cover element to be guided around the force transmission element in a U-shape.

In the context of the invention, the cover device can be set up in such a way that the cover element is deflected by the deflecting elements in each case by at least 30 ° and / or at most 60 °, preferably approximately 90 °. A sliding access area can be provided in a particularly space-saving manner.

Advantageously, the force transmission element and / or the motor can be attached to or integrated in or on the door or flap in such a way that a joint pivoting takes place when the door or flap is opened or closed. In one embodiment, the gear element is movably connected to the vehicle body, in particular via a joint. Alternatively, it is fundamentally possible for the force transmission element and / or the motor to be movably or rigidly connected to the vehicle body, while the transmission element is attached to the door or flap.

Exemplary embodiments of the invention are also explained in more detail below with reference to figures. Features of the exemplary embodiments can be combined individually or in a plurality with the claimed objects, unless stated otherwise. The claimed protection areas are not limited to the exemplary embodiments.

• 1: Schematische Darstellung eines Getriebeelements mit einer Abdeckungseinrichtung;
• 2: Schematische Detail-Darstellung des Wechselwirkens des Kraftübertragungselements mit dem Getriebeelement innerhalb des Zugangsbereichs;
• 3: Schematische Darstellung des Getriebeelements von der gegenüberliegenden Seite verglichen mit der Darstellung in 1;
• 4: Schematische Detail-Darstellung des Getriebeelements ohne Abdeckungseinrichtung;
• 5: Schematische Darstellung einer Antriebseinheit für eine Tür oder Klappe eines Kraftfahrzeugs für ein motorisiertes Verschwenken der Tür oder Klappe.

Show it:

• 1 : Schematic representation of a gear element with a cover device;
• 2 : Schematic detailed representation of the interaction of the power transmission element with the transmission element within the access area;
• 3 : Schematic representation of the gear element from the opposite side compared to the representation in 1 ;
• 4 : Schematic detailed representation of the gear element without cover device;
• 5 : Schematic representation of a drive unit for a door or flap of a motor vehicle for motorized pivoting of the door or flap.

The 1 and 3 show a gear element 2 with a cover device for a drive unit 1 , in the 5 is shown. A motor-rotatable power transmission element 3 preferably made of metal, in particular a pinion as in 2 shown can with the gear element 2 , especially a rack as in 4 shown interact so that a rotation of the power transmission element 3 into a translational movement 5 of the gear element 2 can be converted. A motorized pivoting of a door 10 or flap of a motor vehicle 20 , as in 5 indicated, can be made possible without the dirt or dust leading to increased friction and premature wear of the drive unit 1 to lead.

The disclosure content of the 2 the publication DE102008026040A1 incorporated by reference herein into this disclosure, which shows how an elongated rack and pinion drive 3b , which can also be called a gear element, from a motor-driven gear 3c , which can also be referred to as a power transmission element, is driven to perform a translational movement and moves freely between the motor vehicle door and the motor vehicle body when the motor vehicle door is opened or closed. Instead of the rack and pinion drive, one or more links, a cable drive or a spring spoke arrangement can in principle also be used as the door drive at this point.

The gear element 2 has strip-shaped lateral covers 7 . 8th on what the area of engagement 19 , ie cover the tooth profile laterally in the longitudinal direction. The covers 7 . 8th stand on the engagement side 16 at the engagement area 19 in particular by the extent of the thickness of the cover element 6 , which is a flat belt here, for example. In the area outside the access area 15 thus limit the lateral covers 7 . 8th each flush to the outside, preferably at a 90 ° angle to the cover element 6 on, the flat, loose and immediately on the engagement side 16 the area of engagement 19 rests and thereby covers it. The cover element 6 so it rests, so to speak, on the tooth tips of the toothed rack, wherein the tooth tips can be flattened, for example, as shown.

The cover element 6 is like in the 1 and 3 shown at opposite end areas 17 . 18 the gear element by means of fixations 9 attached, preferably as shown by means of a screw connection. In one embodiment, the fixations 9 or by screwing the screw connection also the lateral covers 7 . 8th firmly on the gear element 2 appropriate. Additional connection means can thus be saved.

A through hole serves as an articulated connection 22 , via which the gear element as in 5 shown around an axis of rotation 23 articulated with a door 10 a motor vehicle 20 can be connected while the power transmission element 3 to the vehicle body 21 is coupled.

That flat on the engagement side 16 the area of engagement 19 overlying cover element 6 or the flat belt is on a first deflecting element 11 approximately 90 ° from the gear element 2 away to a second deflecting element 12 redirected there. In one embodiment, the power transmission element 3 between the first deflecting element 11 and the second deflecting element 12 arranged. By redirecting the cover element 6 on the second deflection element 12 the cover element can thus in particular also at approximately 90 ° 6 around power transmission element 3 be led around. A third deflection element 13 in particular at an equal distance from the gear element 2 like the second deflecting element 12 serves to deflect the cover element 6 back to the gear element 2 , in particular also at an approximately right angle and / or to a fourth deflection element 14 out. The fourth deflecting element 14 is at the same distance from the gear element 2 arranged like the first deflecting element 11 and so the cover element 6 again for lying on the engagement side 16 the area of engagement 19 redirect.

In one embodiment, the fixations 9 set up to cover the element 6 flat at both ends on the engagement side 16 the area of engagement 19 fix. Between a first end of the cover element 6 in a first end area 17 of the gear element 2 and the fourth deflecting element 14 and / or a second end of the cover element 6 in a second end area 18 of the gear element 2 and the first deflecting element 11 is the cover element 6 therefore flat and directly on the engagement side 16 the area of engagement 19 and therefore reliably covers it from this side.

The deflection axes 26 the deflection elements 11 . 12 . 13 . 14 are in particular aligned parallel to one another, in particular in the lateral direction, that is to say transversely to the longitudinal direction. The deflection axis preferably runs 26 parallel to the axis of rotation 23 , The deflection elements 11 . 12 . 13 . 14 are preferred pulleys that are rotatable about the deflection axis 26 are stored, preferably on the housing 25 for the power transmission element 3 as in 5 shown.

The access area 15 , in which, for example, the deflection elements are shown 11 . 12 . 13 . 14 make sure that the engaging side 16 the area of intervention 19 for an interaction with the power transmission element 3 is temporarily not covered, as in 5 shown by a housing 25 for the power transmission element 3 Shielded, covered and protected from environmental influences including dirt or dust.

The extension of the access area 15 in the longitudinal direction corresponds to at least 30% of the length of the gear element 2 or the area of intervention 19 in the longitudinal direction and / or at most 50% of the length of the gear element 2 or the area of intervention 19 longitudinal.

The mode of operation is as in 5 illustrated. An engine 3 brings the power transmission element 3 in rotation, which in turn is a translational movement 5 of the gear element 2 caused in the longitudinal direction. Because the housing 25 and the bearing with the axis of rotation 24 of the power transmission element 3 to the door 10 of the motor vehicle 20 is coupled while the transmission element 2 about the connection 22 with the hinge axis 23 is coupled to the vehicle body, the door is pivoted 10 for opening or closing the door 10 ,

During the translation movement 5 of the gear element 2 in the longitudinal direction relative to the housing 25 that will be on the gear element 2 overlying cover element 6 or the flat belt accordingly on the deflection elements 11 . 12 . 13 and 14 deflected and so around the power transmission element 3 inside the case 25 led around.

The area of intervention 19 of the gear element 2 , for example the tooth profile, and the power transmission element 3 remain protected from dirt and dust even during operation.

In particular, the covering device, which is closed to the surroundings, is capable of the engagement area 19 that with the power transmission element 3 can be engaged to cover at least 95%, preferably 98%. In particular, there may be a narrow gap at the interfaces of the cover element with the lateral covers. However, the amount of dust and dirt that can reach the engagement area through such a narrow gap is negligible for the friction and wear. In particular, the cover device does not provide an airtight or moistureproof cover. In one embodiment, however, the covering device can in principle also be airtight and / or moisture-tight, for example by providing Interface sealing devices can be set up. A 100% coverage by the coverage device is then achieved.

LIST OF REFERENCE NUMBERS

1

drive unit

2

gear element

3

Power transmission element

4

electric motor

5

translational motion

6

cover member

7

First lateral cover

8th

Second lateral cover

9

fixation

10

door

11

First deflecting element

12

Second deflection element

13

Third deflection element

14

Fourth deflecting element

15

access area

16

engaging side

17

End area of the gear element

18

Opposite end area of the gear element

19

engagement area

20

motor vehicle

21

vehicle body

22

joint connection

23

axis of rotation

24

axis of rotation

25

casing

26

deflection axis

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102008026040 A1 [0002, 0056]

Claims (15)

Drive unit (1) for a door (10) or flap of a motor vehicle (20) for motorized pivoting of the door (10) or flap, wherein the drive unit (1) is an electric motor (4), a power transmission element (3), through which Electric motor (4) can be rotated, and an elongated gear element (2), which can be moved relative to the power transmission element (3), wherein the drive unit (1) is set up in such a way that by interaction of the power transmission element (3) with the Gear element (2) a rotation of the power transmission element (3) can be converted into a translational movement (5) of the gear element (2) for motorized pivoting of the door (10) or flap, characterized in that a cover device (6, 7, 8, 9, 11, 12, 13, 14) is provided for the transmission element (2), which can generate a displaceable access area (15) for the transmission element for the force transmission element (3). Drive unit (1) according to the preceding claim, characterized in that the cover device (6, 7, 8, 9, 11, 12, 13, 14) comprises a cover element (6) and the drive unit (1) is set up in such a way that the cover element (6) is moved outside the access area (15) together with the gear element (2) relative to the power transmission element (3) and / or is moved within the access area (15) relative to the gear element (2). Drive unit (1) according to the preceding claim, characterized in that the cover element (6) is arranged on an engagement side (16) of the transmission element (2), on which the interaction of the force transmission element (3) with the transmission element (2) can take place. Drive unit (1) according to the preceding claim, characterized in that the cover element (6) lies directly and / or loosely on the engagement side (16) of the gear element (2) outside the access area (15). Drive unit (1) according to one of the three preceding claims, characterized in that the cover element (6) in one end region (17) or two opposite end regions (17, 18) is fixedly attached to the gear element (2). Drive unit (1) according to one of the preceding claims, characterized in that the drive unit (1) is set up in such a way that the access area (15) moves together with the force transmission element (3) relative to the transmission element (2) when the door (10 ) or flap is pivoted. Drive unit (1) according to one of the preceding claims, characterized in that the gear element (2) comprises an engagement area (19) which is designed for direct interaction with the force transmission element (3), and / or the covering device (6, 7, 8, 9, 11, 12, 13, 14) covers the engagement area (19) of the gear element (2) closed to the environment. Drive unit (1) according to the preceding claim, characterized in that the engagement region (19) is a tooth profile or a thread, the gear element (2) is a toothed rack, a worm shaft or a threaded spindle, and / or the force transmission element (3) is a gear wheel , a pinion, a worm wheel or a spindle nut. Drive unit (1) according to one of the seven preceding claims, characterized in that the force transmission element (3) is arranged between the cover element (6) and the gear element (3) and / or the cover element (6) within the access area (15) around the Power transmission element (3) runs. Drive unit (1) according to one of the eight preceding claims, characterized in that the cover device (6, 7, 8, 9, 11, 12, 13, 14) for a lateral cover (7) or two lateral covers (7, 8) Covering the gear element (3) outside the access area (15) and / or inside the access area (15) and / or the cover element (6) adjoins the lateral cover (7) or the two lateral covers (7, 8), in particular flush with the outside. Drive unit (1) according to the preceding claim, characterized in that the lateral cover (7) or the two lateral covers (7, 8) are fixedly attached to the gear element (2) and / or are strip-shaped. Drive unit (1) according to one of the ten preceding claims, characterized in that the cover element (6) is a belt or flat belt and / or at least one deflection element (11, 12, 13, 14) for deflecting the cover element (6) for production the access area (15) is provided. Drive unit (1) according to the preceding claim, characterized in that the deflecting element (11, 12, 13, 14) is a deflecting roller or a pin and / or that Cover element (6) has the same width as the gear element (2). Drive unit (1) according to the preceding claim, characterized in that at least two, three or exactly four deflection elements (11, 12, 13, 14) are provided in order to cover the cover element (6) within the access area (15) around the force transmission element (3 ) to lead around. Drive unit (1) according to the preceding claim, characterized in that the cover device (6, 7, 8, 9, 11, 12, 13, 14) is set up in such a way that the cover element (6) is deflected by the deflecting elements (11, 12, 13, 14) is deflected by at least 30 ° and / or at most 60 °, preferably approximately 90 °.

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