ELECTRIC FLAP DRIVE, FLAP ARRANGEMENT AND FLAP OPERATING METHOD

Description

[0001] The present invention relates to an electric flap drive, in particular for a charging or refueling flap of a motor vehicle, with an electric motor having a drive shaft and an output shaft that can be coupled to a flap.

[0002] Furthermore, the present invention relates to a flap arrangement with a flap for closing an opening and with an electric flap drive by means of which the flap can be moved between a closed position and an open position and / or between an open position and a closed position.

[0003] Finally, the present invention relates to a method for opening and / or closing a flap by means of an electric flap actuator.

[0004] Electric tailgate actuators are generally known. For example, it is known to open and / or close the tailgate of a motor vehicle electrically. Opening is usually achieved via a handle accessible on the outside of the tailgate. Closing is typically achieved via a separate control button located in the area of ​​an interior trim panel of the tailgate and accessible when the tailgate is open.

[0005] Mechanical opening systems are known for fuel filler flaps and loading flaps on motor vehicles. For example, it is known to push against the flap by hand, which unlocks it and causes it to spring open slightly due to a mechanical spring tension. The flap can then be pivoted into the open position by hand. It is also known to perform the unlocking electromechanically from a distance, for example, by means of a button inside the vehicle. Closing the opening is usually done manually until it reaches a locking position, in which the flap then remains locked and the opening is closed.

[0006] Charging or fuel filler flaps typically feature a kind of bulkhead behind the flap, from which, for example, a fuel filler neck or charging port extends. In this case, the flap does not necessarily need to be sealed against the surrounding vehicle body. Water entering the charging flap area is collected by the bulkhead and drained away, for example, via a drip opening or similar feature.

[0007] It is already common practice to electrically actuate charging flaps for electric vehicles (pure electric vehicles or plug-in hybrids). In many cases, a button is provided next to the charging flap for the operator to press. Pressing the button opens the flap electrically to the open position. Pressing the same button again closes the flap. A problem with this method is that the electronic button must be accessible on the exterior of the vehicle body, which results in considerable manufacturing effort and poses challenges regarding sealing. Alternatively, an operating button can be provided inside the vehicle. However, it is generally preferable for the flap to be operated from the outside.

[0008] Furthermore, in winter, the flap can become blocked by a layer of ice around its edge due to freezing rain or similar conditions, which can lead to problems with electric motor operation. European patent application EP 3 734 007 A1 discloses a flap drive for hoods, doors, flaps, and the like of a motor vehicle, comprising an electric motor that opens and closes the hood, door, flap, or the like of the motor vehicle via an electromagnetic brake and clutch unit and a slip clutch. The brake and clutch unit allows the hood, door, flap, or the like to be locked in any pivot position. A torque sensor in the flap drive measures the operator force applied to the hood, door, flap, or the like in order to start the flap drive.

[0009] Against this background, it is an object of the invention to provide an improved electric flap drive, an improved flap arrangement and an improved method for opening and / or closing a flap by means of an electric flap drive.

[0010] The above problem is solved by an electric flap drive, having the features of claim 1, in particular for a charging or refueling flap of a motor vehicle, comprising an electric motor having a drive shaft, an output shaft that can be coupled to a flap, a drive gear arrangement that provides a transmission between the drive shaft and the output shaft, a coupling arrangement comprising an input element connected to the drive shaft and an output element connected to the output shaft, which are frictionally coupled in a basic position, and a sensor arrangement that is configured to detect slippage of the coupling arrangement, as caused by an actuating movement of the flap.

[0011] Furthermore, the problem is solved by a flap arrangement with a flap for closing an opening and with an electric flap drive of the type according to the invention, by means of which the flap can be moved between a closed position and an open position and / or between an open position and a closed position.

[0012] Finally, the above problem is solved by a method according to claim 15, for opening and / or closing a flap by means of an electric flap drive of the type according to the invention, comprising the steps of detecting a slip of the coupling arrangement caused by an actuating movement of the flap and controlling the electric motor to move the flap from the closed position to the open position or vice versa.

[0013] The electric flap actuator can be mounted behind a firewall of the loading or fuel filler flap, allowing for installation in a protected environment. A user's request to open or close the flap is detected by actuating the flap itself. Similar to purely mechanical unlocking systems, the flap is pressed from the closed position (e.g., towards the firewall). This pressing or tapping motion is then detected by the sensor array in the electric flap actuator. Consequently, no external button or other external actuator on the vehicle is required to register the opening request.

[0014] A further advantage of the momentary actuation of the flap itself, in order to ultimately open it motor-driven, is that any ice layer present due to freezing rain or similar conditions is broken up. Such an ice layer can prevent motor-driven opening of the flap in prior art. Alternatively, the electric motor and the associated mechanical actuator components would have to be dimensioned to break up an ice layer electrically, which would lead to larger installation space, higher costs, etc. The inventive design of the electric flap drive allows the use of a relatively small electric motor, and the mechanical components do not need to be designed for such extreme stresses.

[0015] The electric motor drives the drive shaft, which is connected to the input element of the coupling assembly. The output element of the coupling assembly is connected to the output shaft, which can be coupled to the flap or is coupled in the installed state.

[0016] The coupling assembly connects the input and output elements frictionally in a basic position. In other words, the output shaft is driven proportionally to the input shaft (depending on the gear ratio of the drive assembly), without any slippage occurring.

[0017] The frictional coupling can preferably be established by a spring force.

[0018] In other words, the coupling assembly is in its home position during opening and closing movements.

[0019] When the electric motor is not running and the flap is, for example, in a closed position, the coupling assembly is initially in its home position. If, starting from this state, the flap is actuated, for example by a brief push, the coupling assembly disengages from its home position and enters a slip or sliding state, in which the input and output elements move relative to each other. This relative movement can be detected by the sensor assembly in a relatively simple manner. The state of the coupling assembly in which the input and output elements are offset from each other due to the flap actuation can also be referred to as the detection position.

[0020] As soon as the actuating force is released, i.e., the operator no longer presses the flap, the coupling arrangement returns from the detection position to the basic position, preferably by means of the spring force mentioned above.

[0021] It is understood that the flap actuator is preferably designed such that the input element remains essentially stationary or is held in the closed and / or open position relative to the initial position of the coupling arrangement. Actuation of the flap then generally leads to a movement of the output element relative to the held input element, so that slippage occurs from the initial position and consequently the detection position is established.

[0022] Holding the input element can be achieved in various ways. Preferably, this is accomplished by making the drive gear assembly self-locking. This means that the drive gear assembly can be driven via the input shaft but not via the output shaft. Self-locking can be achieved in various ways, for example, by very high gear ratios and / or by using a worm gear.

[0023] The electric damper actuator is capable of detecting damper movement when the damper is in the closed position. Alternatively or additionally, the electric damper actuator is also capable of detecting damper movement when the damper is in the open position. In other words, a slight upward movement of the damper from the open position can trigger the detection position in the coupling mechanism, thus registering the request to close the damper.

[0024] The gear ratio of the drive assembly can be 1:1, but is preferably selected to provide a relatively high ratio between the input shaft and the output shaft. This makes it possible, for example, to use a cost-effective electric motor, such as a DC motor, with an operating speed greater than 4000 revolutions per minute and an operating torque of less than 150 mNm.

[0025] The rotational speed of the output shaft can range from 5 to 50 revolutions per minute during opening and closing movements. The applied torque can range from 0.25 to 10 Nm.

[0026] The drive gear arrangement is preferably a multi-stage spur gear arrangement, which preferably also includes a worm gear, in which the drive shaft has a worm shaft section and a gear of the drive gear arrangement is designed as a worm gear that engages with the worm shaft.

[0027] In this context, a connection is understood to mean that the elements connected by it are forcibly coupled and, in particular, rotate at a proportional speed. A rotationally fixed connection is understood to mean that elements are rigidly connected to one another.

[0028] The electric motor, the drive transmission assembly, the clutch assembly, and the sensor assembly are preferably housed in a flap actuator housing. In this flap assembly, the flap actuator housing is preferably located behind a firewall, on which a charging port or a fuel filler neck protrudes and which generally provides a certain degree of sealing against the vehicle interior.

[0029] The relative movement of the input and output elements during the transition from the home position to the detection position can be a relative rotational offset and / or a relative axial offset. The sensor arrangement can be designed to detect a relative rotational offset and / or a relative axial offset between the input and output elements. Preferably, a Hall sensor arrangement is provided for this purpose. The Hall sensor is preferably mounted in a housing. At least one permanent magnet is preferably fixed to either the input or output element.

[0030] Preferably, a relative axial offset between the input element and the output element is detected, which may, for example, be in a range of 0.2 to 2 mm from the home position to the detection position, which may, for example, correspond to a rotational offset of 1° to 4°.

[0031] Preferably, the sensor arrangement is further configured not only to detect the actuation of the flap, but also to detect the position of the actuator and / or the position of the flap over at least a section of the movement range, preferably over the entire movement range. For example, a Hall sensor can detect the circumferential travel of the input element and / or output element.

[0032] The output shaft can be directly coupled to a flap, for example, by being rotationally fixed to it. However, a flap mechanism can also be arranged between the output shaft and the flap. This could be, for example, a multi-link arrangement, another spur gear drive, or something similar.

[0033] The task is thus completely solved.

[0034] It is particularly advantageous if the drive gear arrangement is arranged between the drive shaft and the input element, wherein the drive gear arrangement preferably has a self-locking worm gear.

[0035] In this arrangement, an output shaft axis is preferably arranged parallel to the axes of gears of the drive transmission assembly.

[0036] According to a further preferred embodiment, the input element and the output element are designed such that the input element and the output element are axially offset from each other during a relative rotation.

[0037] This is usually achieved by including a contour with inclined sections between the input element and the output element, so that a relative rotation inevitably leads to a relative axial offset.

[0038] Preferably, the sensor arrangement is configured to detect a relative axial offset between the input element and the output element. Alternatively or additionally, the sensor arrangement can also be configured to detect a relative rotational offset between the input element and the output element.

[0039] According to a further overall preferred embodiment, the coupling arrangement is designed as a two-stage slip clutch, wherein the input element and the output element are displaceable relative to each other by a limited first slip amount when a first torque is applied to the output element, and are displaceable relative to each other by a second slip amount that is greater than the first slip amount when a second torque is applied to the output element, so that incorrect operating movements of the flap can be absorbed.

[0040] The basic idea behind this embodiment can be explained as follows. When an initial torque is applied to the output element (for example, by applying an actuating movement to the flap), this initial torque is sufficient to release the frictional engagement of the clutch assembly, causing it to enter a slip state and thus a detection position. This detection position can then be detected by the sensor assembly, allowing the electric motor to initiate movement of the flap.

[0041] The actuating movements on the flap, which are of the type of tactile movements, usually have a range of motion of a few millimeters up to a maximum of about 2 cm, in particular a maximum of 1.5 cm.

[0042] If, on the other hand, an actuating force is exerted on the flap, for example starting from the open position, which is so great that the flap is actuated "forcibly" towards the closed position, the second torque is exerted on the output element, which is greater than the first torque.

[0043] This allows the input element and the output element to be offset relative to each other by a second slip amount, which is greater than the first slip amount, so that such incorrect operating movements of the flap can be absorbed or compensated.

[0044] A first stage of the slip clutch is therefore a slippage or sliding of the clutch assembly to a limited extent, which is desired and serves to detect an actuating movement of the flap.

[0045] The second stage of the slip clutch, however, is designed like a classic slip clutch, in which the input and output elements can move relatively freely relative to each other in order to compensate for or absorb operating errors. On the other hand, the function of the classic slip clutch can also be used, for example, for emergency release should the flap not open electrically due to a failure of the vehicle's electronics or a battery discharge.

[0046] It is particularly advantageous if the first slip amount corresponds to a rotational offset between the input element and the output element of less than or equal to 45°, in particular less than 20° and preferably less than 10°.

[0047] Alternatively or cumulatively, the second slip amount for the second stage of the slip clutch corresponds to a second rotational offset greater than 30°, in particular greater than 90° and preferably greater than or equal to 360°.

[0048] In other words, the input and output elements in the second stage of the slip clutch can be rotated relative to each other by large amounts of rotation to compensate for operator errors.

[0049] Preferably, the input element and the output element can be moved one or more times by 360° relative to each other to compensate for such operating errors.

[0050] Furthermore, it is generally advantageous if the input element or the output element has a circumferentially extending first coupling contour, wherein the other element has a circumferentially extending second coupling contour which includes a contour follower, wherein the contour follower is preferably pressed against the first coupling contour with an axial spring force.

[0051] The engagement of the contour follower with the first coupling contour allows, firstly, the application of friction to establish the basic position of the coupling assembly. Secondly, the first coupling contour can be designed such that the contour follower, and thus the connected element, is axially displaced relative to the other element when a relative rotation occurs. This is particularly relevant when transitioning from the basic position to the detection position.

[0052] The axial spring force can be set, for example, by means of a disc spring, a ring spring or by means of a plurality of individual springs.

[0053] It is particularly preferred if the first coupling contour has a contour base into which the coupling follower is pressed in the basic position and has a first inclination section which is inclined relative to the circumferential direction by a first inclination angle in the range of 10° to 65°.

[0054] The contour base can, for example, be an axially extending recess into which the clutch follower engages. The first inclination section extends from the contour base. The first inclination angle, in conjunction with the axial spring force and friction parameters of the clutch contour and the clutch follower, is coordinated such that the frictional engagement of the clutch assembly is released when the flap is actuated.

[0055] Preferably, the first inclination angle lies in a range of 30° to 60°, in particular from 40° to 50°.

[0056] Furthermore, it is advantageous if the first coupling contour has a second inclined section which is inclined relative to the circumferential direction by a second angle of inclination which is less than 90° and greater than the first angle of inclination.

[0057] The second slope section connects to the first slope section in the circumferential direction. In other words, the first slope section is located between the contour base and the second slope section.

[0058] The second tilt angle is greater than the first tilt angle. Consequently, a greater force or torque must be applied to the output element to force the contour follower into the region of the second tilt section.

[0059] In other words, when the user operates the flap, they initially experience a slight resistance (corresponding to the first tilt section), which is desirable and provides tactile feedback that they are indeed operating the flap. However, if the user presses the flap beyond the usual extent, for example, forcefully from the open position towards the closed position, the contour follower enters the area of ​​the second tilt section. In other words, the user experiences a high resistance force, indirectly indicating that their operation is incorrect. If this force is applied continuously, the contour follower moves further along the second tilt section.

[0060] Preferably, the first coupling contour has a straight section following the second inclination section, which is aligned parallel to the circumferential direction.

[0061] When the large incorrect operating force is applied, the clutch follower consequently moves from the second inclined section to the straight section, where a rotation of the input element and the output element is possible with relatively little force.

[0062] This prevents mechanical damage to the flap drive in the event of incorrect operation or emergency release. The described coupling contour with the first inclined section, the second inclined section and the straight section is preferably mirror-symmetrical in the circumferential direction, so that the actuation movements can take place in both directions.

[0063] Furthermore, such a mirror-symmetrical first coupling contour is preferably provided multiple times in the circumferential direction, wherein the first coupling contours are each connected to each other via the straight sections.

[0064] In the second stage of the slip clutch, a relative movement of the first and second input elements occurs such that the clutch follower (or clutch followers, if each first clutch contour has its own clutch follower) is displaced from the contour base, via the two inclined sections, first to the straight section. From there, it moves into the next first contour section in the circumferential direction and consequently again via a second inclined section, a first inclined section to its contour base, and from there again via a first inclined section, a second inclined section to another straight section, and so on. This preferably results in a type of slip clutch noise, in which each engagement of a clutch follower in a further first clutch contour corresponds to a clicking sound.

[0065] The person performing the incorrect operation receives a kind of acoustic feedback indicating that this type of movement is obviously incorrect. On the other hand, the movement does not cause any damage to the electric flap actuator.

[0066] The second stage of the slip clutch is therefore a kind of safety stage.

[0067] According to a further preferred embodiment, the input element is designed as a ring element which is axially displaceable on the output element, wherein preferably at least one sensor element of the sensor arrangement is fixed on the input element.

[0068] The output element preferably has radially internal axial teeth into which a shaft of a flap mechanism or the like can be inserted. The input element is preferably mounted as a ring element in the region of an outer circumference of the output element. The sensor element of the sensor arrangement is preferably a permanent magnet. Preferably, a plurality of such sensor elements are distributed around the circumference of the input element.

[0069] In another preferred embodiment, the sensor elements (e.g. magnets) can be arranged so that a Hall sensor (or the like) can detect a circumferential path of the input element (or possibly the output element).

[0070] Furthermore, it is advantageous if a spring arrangement is arranged between the output element and the input element, by means of which the contour follower is pressed against the first coupling contour.

[0071] The spring arrangement can, for example, be a ring spring, similar to a ring-shaped disc spring.

[0072] Furthermore, it is advantageous if the electric flap drive has a housing in which the electric motor is arranged, wherein the drive shaft and the output shaft are preferably aligned at an angle to each other.

[0073] The skewed position of the output shaft and input shaft allows for the advantageous integration of a worm gear in a design.

[0074] The output shaft is preferably axially fixed within the housing.

[0075] It is particularly advantageous if the output shaft is rotatably mounted in relation to the housing, the housing having an opening through which a flap mechanism can be connected to the output shaft.

[0076] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0077] Exemplary embodiments of the invention are shown in the drawing and are explained in more detail in the following description. They show: Fig. 1 a schematic representation of a motor vehicle with a loading flap; Fig. 2 a schematic sectional view of a loading flap assembly; Fig. 3 a schematic representation of an electric flap drive; Fig. 4 a schematic representation of a coupling assembly with a first coupling contour and a coupling follower acting thereon; Fig. 5 a functional representation of an axial offset or a rotational offset against a torque applied to an output element of the coupling assembly. Fig. 4is exercised; Fig. 6 a representation of a further embodiment of an electric flap actuator; Fig. 7 a representation of the flap actuator of the Fig. 6 without a housing enclosing it; Fig. 8 a coupling arrangement of the flap drive of the Figs. 6 and 7 in a basic position; Fig. 9 the coupling arrangement of the Fig. 8 in a capture position; Fig. 10 the coupling arrangement of the Fig. 8 in a slip position; and Fig. 11 a schematic representation of the coupling arrangement of the flap drive of the Figs. 6 to 10 .

[0078] In Fig. 1Figure 1 shows a schematic representation of a motor vehicle K, which has a body 12 on which a charging flap 10 is arranged. The charging flap 10 provides access to a charging socket for charging the battery of the motor vehicle K. Instead of the charging flap 10, it could also be a fuel filler flap. In general, the present invention also relates to other types of flaps, such as tailgates of motor vehicles, fire dampers in buildings, and media access panels in the interiors of motor vehicles, to name a few examples.

[0079] Fig. 2 is a schematic cross-sectional view along an essentially horizontal direction through part of the bodywork 12 and the loading flap 10.

[0080] It can be seen that a charging socket 14 is arranged behind the charging flap 10, into which a charging plug 16 can be inserted. Furthermore, an electric flap drive 20 is provided, by means of which the flap 10 can be moved from the closed position 22 shown to an open position 24 and vice versa.

[0081] The flap actuator 20 is located behind a bulkhead 21, which seals the area behind the charging flap 10 and against which the charging socket 14 projects. Furthermore, an opening for a flap mechanism, a flap drive, or the like is provided in the bulkhead.

[0082] A movement of the flap 10 from the closed position 22 to the open position 24 can be initiated by an actuating movement, such as a probing movement B1, on the loading flap 10 itself. This pushes the loading flap 10 from the closed position 22 shown into a first probing position 22a. The stroke of movement can be, for example, in the range of 0.5 to 20 mm, but is preferably in the range of approximately 1 mm to 15 mm.

[0083] This tactile actuation B1 is detected inside the flap drive 20, so that an opening movement can then be initiated from this point.

[0084] On the other hand, starting from the open position 24, a second tactile movement B2 can also be exerted on the flap, with which the flap 10 moves from the open position 24 to a second tactile position 24a, the range of movement being similar to that in connection with the first tactile position 22a. The second tactile movement B2 can in turn be detected inside the flap drive in order to initiate a closing movement from the open position 24 to the closed position 22.

[0085] In Fig. 2 Furthermore, a pivot axis 27 of the flap 10 is shown schematically. The pivot axis 27 can, for example, run vertically, as shown, but can also run horizontally.

[0086] In Fig. 3 A schematic representation of an embodiment of an electric flap drive 20 in the form of a block diagram with a simplified gear representation is shown.

[0087] The flap actuator 20 has an electric motor 30. The electric motor 30 can, for example, be a 12-volt DC brushed motor with an operating speed in the range of 5,000 to 10,000 revolutions per minute and an operating torque in the range of 2 mNm to 40 mNm.

[0088] The electric motor 30 has a motor shaft in the form of a drive shaft 32.

[0089] The drive shaft 32 is connected via a schematically represented drive gear assembly 34 to an input element 42 of a coupling assembly 40. An output element 44 of the coupling assembly 40 is connected to an output shaft 46, which in turn is coupled to the flap 10 via a flap mechanism 36. The flap 10 is pivotable about the pivot axis 27.

[0090] It is understood that a pivoting movement about a single axis is only one example. It is understood that the flap mechanism 36 can also be a multi-link arrangement in which the flap is pivoted in such a way that the pivot axis moves in space.

[0091] As it is in Fig. 3 As shown, actuation movements B1 / B2 can be applied to the flap 10, which act on the output shaft 46 via the flap mechanism 36 and consequently on the output element 44.

[0092] The coupling arrangement 40 is a friction-fit coupling arrangement in which the input element 42 and the output element 44 are pressed together by a spring force F. The spring force F and other parameters of the coupling arrangement (such as friction parameters, gear ratios, etc.) are selected such that opening and closing movements of the flap occur in the friction-fit state of the coupling arrangement 40, which is therefore a basic position.

[0093] The flap actuator 20 also includes a control arrangement 50, by means of which the electric motor 30 is controlled. The control arrangement 50 is further connected to a sensor arrangement 52, which is assigned to the coupling arrangement 40.

[0094] The sensor arrangement 52 is preferably configured to detect slippage of the coupling arrangement caused by an actuating movement B1 or B2 of the flap 10. Consequently, the sensor arrangement 52 is used to detect whether an operator wishes to open or close the flap, which they communicate by a momentary actuation B1 or B2 on the flap 10.

[0095] The drive gear assembly 34 is preferably designed to be self-locking. A probing movement B1 / B2 of the flap 10 and consequently of the output element 44 therefore leads to slippage, since the input element 42 is held essentially immobile by the self-locking drive gear assembly 34.

[0096] The electric motor 30, the control arrangement 50, the drive gear arrangement 34, the clutch arrangement 40 (at least the input element 42) and the sensor arrangement 50 are preferably arranged in an area behind the firewall 21 and are preferably housed in a common casing, which in Fig. 3 however, it is not shown.

[0097] In general, the slipping movement of the coupling arrangement 40 could be detected by detecting the relative rotational offset between the input element 42 and the output element 44 using the sensor arrangement 52.

[0098] Preferably, however, the input element 42 and the output element 44 engage with each other via contours which result in a relative axial offset between the input element 42 and the output element 44 when there is a relative rotation of the input element 42 and the output element 44.

[0099] An example of a coupling arrangement 40 with such contours is shown in Fig. 4 depicted.

[0100] The input element 42 is designed as a rotary element, which is generally rotatable in a circumferential direction U. The same applies to the output element 44. The input element 42 has a first coupling contour 56. The output element 44 has a second coupling contour 58.

[0101] The first coupling contour 56 includes a contour base 60. Furthermore, the first coupling contour 56 has a first inclined section 62 extending from the contour base 60. The first coupling contour 56 also has a second inclined section 64 extending from the first inclined section 62. Finally, the first coupling contour 56 has a straight section 66 adjoining the second inclined section 64 and oriented circumferentially U.

[0102] As it is in Fig. 4 As shown, the first coupling contour 56 is mirror-symmetrical with respect to a circumferential position according to the contour base 60, thus having two first inclination sections 62 and two second inclination sections 64.

[0103] The second coupling contour 58 has a contour follower 68.

[0104] The contour follower 68 engages in the representation of the Fig. 4at the contour base 60 of the first coupling contour 56.

[0105] The contour follower 68 extends axially from an unspecified straight section of the second coupling contour 58 extending in the circumferential direction U.

[0106] The first inclined section 62 is inclined at a first inclination angle β1 with respect to the circumferential direction U. The second inclined section 64 is inclined at a second inclination angle β2 with respect to the circumferential direction U. The second inclination angle β2 is greater than the first inclination angle β1.

[0107] The output element 44 is pressed against the input element 42 by means of an axial spring force F (or vice versa). The contour follower 68 is therefore located in the contour base 60 such that in the basic position G described above, which is Fig. 4 The input element 42 and the output element 44 are shown in solid lines, and are frictionally coupled in the circumferential direction U.

[0108] If a torque T directed in the circumferential direction U is exerted on the output element 44, the coupling arrangement 40 remains in the basic position G as long as the torque T does not exceed a first torque threshold T 1, as defined in Fig. 5 is shown.

[0109] When the torque T exceeds the first torque threshold T1, the frictional engagement of the home position G disengages and the clutch follower 68 enters the region of the first inclination section 62. This results in slippage of the clutch assembly 40, specifically in the form of a first slip amount by a first rotational offset α1 (corresponding to the circumferential length of the first inclination section 62). Furthermore, because the clutch follower 68 follows the inclination of the first inclination section 68, a relative axial offset occurs between the input element 42 and the output element 44, which in Fig. 4 shown with H 1.

[0110] This area of ​​slippage within α1 or H1 is also referred to as detection position E, as is also the case in Figs. 4 and 5 is shown.

[0111] If the torque T exceeds a second threshold value T₂, which is greater than the first threshold value, the contour follower 68 enters the area of ​​the second incline section 64. If this torque T, greater than or equal to T₂, is exerted on the output element 44, the contour follower 68 finally enters the area of ​​the straight section 66. This too is in Fig. 5 schematically represented.

[0112] If the clutch follower 68 is located in the area of ​​the second incline section 64 or in the area of ​​the straight section 66, a so-called slip position R is consequently established, as described in the Figs. 4 and 5 is shown.

[0113] The basic position is generally a fixed circumferential position. However, the detection position E and the sliding position R are respective circumferential direction areas.

[0114] The coupling arrangement 40 is therefore designed as a two-stage slip clutch.

[0115] If a sensor arrangement 52 detects that the clutch follower 68 is in the first tilt range 62 (for example, by detecting a relative axial offset of at least 0.5 H 1 or the like), an electromechanical movement of the flap 10 is initiated.

[0116] However, if the clutch follower 68 is in the slip position R, this occurs due to a significantly higher force exerted on the flap 10, resulting in a corresponding torque T on the output element 44 that is greater than T₂. Such force exertion is generally an operating error. Consequently, this operating error in the clutch assembly 40 leads to slippage extending into the area where the clutch follower 68 is located within the straight section 66. In this area, relative rotation is possible even at very low torque.

[0117] Respective arrangements of a first coupling contour 56 and a second coupling contour 58 can be distributed over the circumference of the input member 42 and the output member 44, for example three, four, five, six, seven or eight such coupling contour pairs.

[0118] In the event of such an incorrect operation, a clutch follower 68 would consequently slip out of its assigned first clutch contour 56, but via the straight section 66 fall into the next first clutch contour in the circumferential direction, from there be pushed out of the next first clutch contour again in the same direction of rotation, and again via another straight section 66 to the third first clutch contour, and so on. In the event of such an incorrect operation, this will result in a clicking detent noise, so that the operator notices that an incorrect operation is taking place.

[0119] In the Figs. 6 to 11 Another embodiment of an electric flap actuator is shown. The electric flap actuator 20', which is located in the Figs. 6 to 11 The depicted mechanism generally corresponds in terms of structure and function to the flap drive, which, in relation to the Figs. 2 to 5This has been described. Identical elements are therefore identified by the same reference symbols. The differences are explained below.

[0120] The electric flap drive 20' shows, as is in Fig. 6 The figure shows a housing 70 having an opening 71 through which an output shaft 46' is accessible. The output shaft 46' is designed, for example, with a coupling section such as an axial internal toothing into which a shaft or another element of a flap mechanism 36 can be inserted.

[0121] Furthermore, an electrical connection 72 is formed on the outer circumference of the housing 70, via which a control arrangement 50' located inside the housing 70 can be contacted.

[0122] As it is in Fig. 7As shown, the drive gear arrangement 34' includes a self-locking worm gear 74, which comprises a worm shaft on the drive shaft 32' and a worm wheel. The drive shaft 32' is aligned along a motor axis a1.

[0123] The worm gear is non-rotatably connected to an unspecified spur gear and, together with it, is rotatably mounted with respect to a first gear axis a2. The spur gear meshes with another spur gear of a gear unit, which is rotatably mounted with respect to a second gear axis a3. This further gear unit meshes with a gear unit 76, which is rotatably mounted with respect to a third gear axis a4. The gear unit 76 meshes with an input element gear 78, which is fixed to the input element 42 and is located in Fig. 7 is indicated schematically.

[0124] The output shaft 46' is aligned coaxially with an output shaft axis 26'. The output shaft axis 26' and the transmission axes a2, a3, and a4 are aligned parallel to each other. The motor axis a1 is skew to the output shaft axis 26'.

[0125] The output element 44' is arranged as an outer circumferential section on the output shaft 46' and is rigidly connected to it. The input element 42' of the transmission assembly 40' is arranged as a ring element on the outer circumference of the output shaft 46' or the output element 44' and is axially movably mounted with respect to the output element 44'.

[0126] The input element 42 is axially biased against the output element 44 by means of a disc spring or ring-disc spring 80. The input element 42 and the output element 44 can each have coupling contours as described above.

[0127] The coupling arrangement 40' of the flap drive 20' of the Figs. 6 and 7 is in the Figs. 8, 9 and 10 shown in different positions.

[0128] In Fig. 8 The coupling arrangement 40' is shown in the basic position G, in which the input element 42' and the output element 44' are frictionally coupled.

[0129] In Fig. 9 The detection position E is shown, at which the coupling follower 68 has moved over the first incline section.

[0130] In Fig. 10 The slip position R is shown, in which the clutch follower 68 rests on the straight section.

[0131] The exact contours of the 40' coupling arrangement are shown in Fig. 11 depicted. Fig. 11 largely corresponds Fig. 4 The differences are explained in detail below.

[0132] Thus, in Fig. 11It can be seen that the first coupling contour 56', immediately following the contour base 60', has the first inclined section 62', which has the first inclined angle β1. However, the first inclined section 62 includes, circumferentially before the second inclined section 64', a run-out section 62a, where the inclined angle is again significantly smaller. Consequently, a flap movement can initially occur against an initial resistance corresponding to the first inclined angle β1. Then, once a certain distance has been overcome, the flap can still be moved a short distance very easily, and this can be used as a kind of feedback function, so that the user knows that they have now pressed the flap sufficiently to initiate an opening or closing movement.

[0133] Only at this outlet section does the second incline section 64 with the second incline angle β2 begin.

[0134] The second inclination section 64' also has further transition sections (or at least one transition section) following the section that has the second inclination angle β 2, where the inclination angle β is again somewhat smaller.

[0135] In this case too, the transition from the second inclined section 64 to the straight section 66 initially requires a very large force (correspondingly larger than T 2 ), which then decreases again before the straight section 66' is reached.

[0136] These transition sections are in Fig. 11 shown in 64a and 64b.

[0137] It can be seen that the transition section 64a, which follows the second inclination section 64', has a smaller inclination angle β than β 2, but the second transition section 64b again has a higher inclination angle β less than or equal to β 2.

[0138] The shape of the second coupling contour 58' is such that a transition section 68a is provided between the coupling follower 68' and the straight section of the second coupling contour 58', the angle of inclination of which corresponds to that of the second transition section 64b, as shown in Fig. 11 can be seen.

[0139] Provided that the clutch follower 68 is therefore in the detection position E, as described in Fig. 9 As shown, the transition section 68a is adjacent to the transition section 64b, so that a relatively high friction has to be overcome in order to finally move the coupling follower 68' into the area of ​​the straight section 66'. Reference symbol:

[0140] 10 Charging flap 12 Body 14 Charging socket 16 Charging plug 20 Flap drive 21 Firewall 22 Closed position 22 First key position 24 Open position 24 Second key position 26 Output shaft axis 27 Flap pivot axis 30 Electric motor 32 Drive shaft 34 Drive gear assembly 36 Flap gear 40 Coupling assembly 42 Input element 44 Output element 46 Output shaft 50 Control assembly 52 Sensor assembly 56 First coupling contour 58 Second coupling contour 60 Contour base 62 First inclination section (β1) 64 Second inclination section (β2) 66 Straight section 68 Contour follower 70 Housing (20) 71 Opening for 46 72 Electrical connection 74 Self-locking worm gear (34) 76 Gear wheel 78 Input link gear 80 Disc spring 82 Hall sensor (3D) 84 Permanent magnet KMotor vehicle B1First tactile actuation B2Second tactile actuation FForce at 40 GBasic position 40 EDetection position 40 RSlip position 40 UTangential or circumferential direction TTorque T1First torque threshold T2Second torque threshold H1First axial offset (first slip amount) H2Second axial offset (second slip amount) α1First rotational offset (first slip amount) α2Second rotational offset (second slip amount) β1First tilt angle β2Second tilt angle a1Motor axis 32 a2First transmission axis (34) a3Second transmission axis (34) a4Third transmission axis (34)

Claims

1. Electric flap drive (20), in particular for a charging or fuel tank flap (10) of a motor vehicle (K), comprising: - an electric motor (30) which has a drive shaft (32), - an output shaft (46) which is coupleable to a flap (10), - a drive gear arrangement (34) which establishes a transmission ratio between the drive shaft (32) and the output shaft (46), - a clutch arrangement (40) which has an input member (42) connected to the drive shaft (32) and an output member (44) connected to the output shaft (46), which are frictionally coupled in a basic position (G), and - a sensor arrangement (52) which is configured to detect a slip of the clutch arrangement (40) caused by an actuating movement (B1, B2) of the flap (10).

2. Electric flap drive according to claim 1, wherein the drive gear arrangement (34) is arranged between the drive shaft (32) and the input member (42), wherein the drive gear arrangement (34) preferably comprises a self-locking worm gear (74).

3. Electric flap drive according to claim 1 or 2, wherein the input member (42) and the output member (44) are configured such that the input member (42) and the output member (44) are axially displaced relative to each other upon a relative rotation, and / or wherein the sensor arrangement (52) is configured to detect a relative axial displacement (H) between the input member (42) and the output member (44) and / or a relative rotational displacement (α) between the input member (42) and the output member (44).

4. Electric flap drive according to any one of claims 1 to 3, wherein the clutch arrangement (40) is configured as a two-stage slip clutch, wherein the input member (42) and the output member (44) are displaceable relative to each other by a limited first slip amount (H1; α1) upon application of a first torque (T1) to the output member (44), and are displaceable relative to each other by a second slip amount (H2; α2), which is greater than the first slip amount, upon application of a second torque (T2) to the output member (44), so that incorrect operating movements of the flap (10) can be absorbed.

5. Electric flap drive according to claim 4, wherein: - the first slip amount corresponds to a first rotational displacement (α1) less than or equal to 45°, in particular less than 20° and preferably less than 10°, and / or wherein - the second slip amount corresponds to a second rotational displacement (α2) greater than 30°, in particular greater than 90° and preferably greater than or equal to 360°.

6. Electric flap drive according to any one of claims 1 to 5, wherein the input member (42) or the output member has a first clutch contour (56) extending in the circumferential direction (U), wherein the other member (44) has a second clutch contour (58) extending in the circumferential direction (U), which has a contour follower (68), wherein the contour follower (68) is preferably pressed against the first clutch contour (56) with an axial spring force (F).

7. Electric flap drive according to claim 6, wherein the first clutch contour (56) has a contour base (60), into which the contour follower (68) is pressed in the basic position (G), and has a first inclined section (62) which is inclined with respect to the circumferential direction (U) by a first angle of inclination (β1) in the range of 10° to 65°.

8. Electric flap drive according to claim 6 or 7, wherein the first clutch contour (56) has a second inclined section (64) which is inclined with respect to the circumferential direction (U) by a second angle of inclination (β2) which is smaller than 90° and greater than the first angle of inclination (β1).

9. Electric flap drive according to any one of claims 6 to 8, wherein the first clutch contour (56) has a straight section (66) which is aligned parallel to the circumferential direction (U).

10. Electric flap drive according to any one of claims 1 to 9, wherein the input member (42) is configured as a ring element which is mounted axially displaceably on the output member (44), wherein at least one sensor element (84) of the sensor arrangement (52) is preferably fixed on the input member (42).

11. Electric flap drive according to claim 6 and claim 10, wherein a spring arrangement (80) is arranged between the output member (44) and the input member (42), by means of which the contour follower (68) is pressed against the first clutch contour (56).

12. Electric flap drive according to any one of claims 1 to 11, with a housing (70) in which the electric motor (30) is arranged, wherein the drive shaft (32) and the output shaft (46) are preferably oriented skewed to each other.

13. Electric flap drive according to claim 12, wherein the output shaft (46) is mounted rotatably with respect to the housing (70), wherein the housing (70) has an opening (71) via which a flap gear (36) is connectable to the output shaft (46).

14. Flap arrangement, comprising: - a flap (10) for closing an opening and - an electric flap drive (20) according to any one of claims 1 to 13, by means of which the flap (10) is movable between a closed position (22) and an open position (24) and / or between an open position (24) and a closed position.

15. Method for opening and / or closing a flap (10) by means of an electric flap drive (20) according to any one of claims 1 to 13, with the steps of: - detecting a slip of the clutch arrangement (40) which is caused by an actuating movement (B1, B2) of the flap (10), and - actuating the electric motor (30) to move the flap (10) from the closed position (22) to the open position (24) or vice versa.