Method and device for automatically closing a tailgate of a motor vehicle

Abstract

A method for automatically closing a tailgate (3) of a motor vehicle (1) is described, the motor vehicle comprising a vehicle body (2) and a tailgate closing device (16). The tailgate closing device (16) comprises a first (13) and a second closing element (12). A suspension strut (8) is located on a first side (6) of the tailgate (3) and a power strut (9) is located on a second side (7) of the tailgate (3) opposite to the first side (6), wherein the suspension strut (8) and the power strut (9) are both connected to the tailgate (3) and the vehicle body (2). The first closing element (13) is located on the tailgate (3) and the second closing element (12) is located on the vehicle body (2) of the motor vehicle (1). The first closing element and the second closing element (12) are designed to engage with each other during closing of the tailgate (3) and to achieve closing of the tailgate (3). Within the scope of the method, during closing of the tailgate (3), when the distance between the first closing element (13) and the second closing element (12) is less than a threshold value, the torque acting on the tailgate (3) via the power strut (9) is reduced.

Description

Technical Field

[0001] The invention relates to a method for automatically closing a tailgate of a motor vehicle, a device for automatically closing a tailgate of a motor vehicle and a motor vehicle. Background Art

[0002] Tailgates previously designed to be automatically actuated are usually constructed in such a way that a single power strut is located on one side of the tailgate and a suspension strut is located on the other side of the tailgate. Such systems have the disadvantage that the tailgate is distorted due to the different torques on both sides of the tailgate. As a result of this distortion, an offset is caused when the components of the closing mechanism engage with each other. The offset between the first closing element and the second closing element can reach 7.5 mm. In principle, an offset of this order of magnitude is undesirable. This offset prevents the elements of the closing mechanism from engaging with each other for normal function and leads to a failure to close the tailgate, or the closing mechanism is subjected to greater wear and stress. Due to the offset, there is also a risk of the tailgate rebounding during the closing process.

[0003] For example, US 8,103,416 B2 discloses a system and method for the dynamic braking of a tailgate closing system. US 6,719,356 B2 discloses a further system for controlling the automatic actuation of a tailgate, in which two power struts are used, one on each side of the tailgate. Thus, in this case, the problem of the tailgate twisting does not even occur. Other variants for the automatic opening and closing of vehicle doors and in particular of tailgates are disclosed in documents US 6,092,336, WO 01 / 83924 A1 and US 2005 / 0039404 A1. None of the available documents solves the problem of the deflection of the closing mechanism that occurs during the automatic closing when only one power strut is used. Summary of the invention

[0004] Against this background, the problem addressed by the invention is to provide an advantageous method for automatically closing a tailgate of a motor vehicle. A further problem is to provide an advantageous device for automatically closing a tailgate and a corresponding advantageous motor vehicle. These problems are solved by the method according to the invention, the device according to the invention and the motor vehicle according to the invention.

[0005] The method for automatically closing a tailgate of a motor vehicle according to the invention relates to a motor vehicle comprising a vehicle body, a tailgate and a tailgate closing device. The tailgate closing device comprises a first closing element and a second closing element. The first closing element is located on the tailgate. The second closing element is located on the vehicle body of the motor vehicle. The first closing element and the second closing element are designed to engage with each other during closing of the tailgate and to achieve closing of the tailgate.

[0006] The suspension strut is located on a first side of the tailgate. The power strut is located on a second side of the tailgate, which is opposite to the first side of the tailgate. Both the suspension strut and the power strut are connected to the tailgate and the vehicle body. Within the scope of the method according to the invention, during closing of the tailgate, when the distance between the first closing element and the second closing element is less than a threshold value, the torque applied by the power strut and acting on the tailgate is reduced.

[0007] In particular, during closing of the tailgate, when the distance between the first closing element and the second closing element is less than one hundred millimeters (100 mm), for example less than seventy millimeters (70 mm), advantageously less than 40 millimeters (40 mm), the torque applied by the power strut and acting on the tailgate is reduced.

[0008] The method according to the invention has the advantage that the above-mentioned distortion of the tailgate during the closing process is reduced and possibly eliminated, since the torque acting on the tailgate is reduced via the power strut shortly before the tailgate is finally closed. As a result, the above-mentioned offset of the closing elements relative to one another is also reduced and possibly eliminated. This accordingly prevents undesirable wear of the closing elements and avoids insufficient closing of the tailgate or rebounding of the tailgate.

[0009] Within the scope of the invention, the suspension strut has the task of assisting the opening process of the tailgate. The power strut provides the energy for opening and closing the tailgate. Preferably, the kinetic energy of the tailgate is utilized in addition to the torque applied by the power strut, or only for the last part of the tailgate's travel until complete closure.

[0010] In an advantageous variant, the torque applied by the power strut and acting on the tailgate during closing is reduced to 0 Newton meters, for example to 0 Newton meters (0 Nm) to 15 Newton meters (15 Nm). Preferably, the torque applied by the power strut and acting on the tailgate during closing is reduced by 90% to 100%, in other words, to 0% to 10% of the torque applied at the beginning of the closing process. In this way, the difference in torque acting on both sides of the tailgate is reduced and advantageously equalized.

[0011] If the closing process cannot be completed, for example due to insufficient reduction of the offset of the closing elements relative to one another, in an advantageous variant of the method the tailgate is closed repeatedly, whereby the torque acting on the tailgate via the power strut is reduced to a greater extent than in the preceding closing process. Additionally or alternatively, the distance between the first closing element and the second closing element can be increased compared to the preceding closing process, wherein the torque acting on the tailgate via the power strut is reduced. In principle, the closing process can thus be repeated several times.

[0012] The device for automatically closing the tailgate of a motor vehicle according to the present invention comprises a suspension strut, a power strut, a closing device and a controller. The suspension strut is designed to be fixed to the body of the motor vehicle on a first side of the tailgate. The power strut is designed to be fixed to a second side of the tailgate opposite to the first side and to the body of the motor vehicle.

[0013] The closing device comprises a first closing element designed to be arranged on the tailgate and a second closing element designed to be arranged on the vehicle body. The first closing element and the second closing element are designed to engage with each other during closing the tailgate and realize the closing of the tailgate.

[0014] The controller is designed to reduce the torque applied by the power strut and acting on the tailgate as soon as the distance between the first closing element and the second closing element during closing of the tailgate is less than a threshold value, advantageously less than 100 millimeters (100 mm), for example less than 70 millimeters (70 mm), preferably less than 40 millimeters (40 mm). In principle, the device according to the invention is suitable and designed to perform the above-mentioned method according to the invention. The device has the same properties and advantages as the above-mentioned method according to the invention.

[0015] In particular, the controller can be designed to reduce the torque applied by the power strut and acting on the tailgate during the tailgate closing process by 90% to 100%, for example to 0 Newton-meter (0 Nm).

[0016] Furthermore, the controller may be designed to repeat the tailgate closing process if the closing process cannot be completed, in which case the work performed by the power strut is reduced to a greater extent than in the previous closing process and / or the distance between the first closing element and the second closing element is increased, in which case a reduction in torque occurs.

[0017] In principle, the first closing element can be designed as a latching plate or can have the form of a fish mouth. Additionally or alternatively, the second closing element can be designed as a latching plate or can have the form of a fish mouth.

[0018] The motor vehicle according to the invention comprises a tailgate, a body and the above-described device according to the invention. In principle, the motor vehicle according to the invention has the same properties and advantages as the above-described device according to the invention. The motor vehicle is also suitable for carrying out the above-described method according to the invention. The motor vehicle according to the invention can be a passenger car, a truck, a sports utility vehicle, a minivan, a bus or other types of vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other features, properties and advantages of the present invention are described in more detail below with reference to the accompanying drawings based on exemplary embodiments. All features described above and below are advantageous individually and in any combination with each other. However, the exemplary embodiments described below are merely examples that do not limit the subject matter of the present invention.

[0020] Figure 1 A motor vehicle according to the invention is schematically shown;

[0021] Figure 2 Schematically shows a view of the rear part of a motor vehicle according to the invention and the occurrence of torque during the closing process;

[0022] Figure 3 schematically shows a perspective view of the closing device during manual closing of the tailgate;

[0023] Figure 4 schematically shows a perspective view of the closing device during automatic closing of the tailgate;

[0024] Figure 5 Schematically shows a device for automatically closing a back door according to the present invention;

[0025] Figure 6 A flow chart of a variant of the method according to the invention is schematically shown. DETAILED DESCRIPTION

[0026] Figure 1 A motor vehicle according to the invention is schematically shown. Figure 1 The motor vehicle 1 according to the invention shown comprises a body 2 , a tailgate 3 and a device 4 according to the invention for automatically closing the tailgate 3 .

[0027] Figure 2 A motor vehicle according to the invention and the torques occurring during the closing process are schematically shown. In this case, the vehicle 1 is shown in a perspective view from the rear. The vehicle 1 comprises a luggage compartment 5 which can be closed by means of a tailgate 3. The tailgate 3 is shown in the open state.

[0028] A suspension strut 8 is located on the first side 6 of the tailgate 3. The suspension strut 8 is connected to or fixed to the tailgate 3 on the first side 6 on the one hand. Furthermore, the suspension strut 8 is preferably fixed to the vehicle body 2 at a position on the first side of the luggage compartment 5. Furthermore, a power strut 9 is located on the second side 7 of the tailgate 3 opposite the first side 6. The power strut 9 is fixed to the tailgate 3 on the one hand and to the vehicle body 2 on the other hand, preferably at a position on the second side of the luggage compartment 5 (opposite the first side of the luggage compartment).

[0029] Furthermore, the motor vehicle 1 comprises a closing device for closing the luggage compartment 5 by means of the tailgate 5. The closing device comprises a first closing element 13 located on the body 2 in the region of the luggage compartment 5 and a second closing element 12 located on the tailgate 3. The first closing element 13 and the second closing element 12 are designed to engage with each other during closing of the tailgate 3 and to close the tailgate 3 or to effect closing of the tailgate.

[0030] During automatic opening of the tailgate 3, a torque 10 is applied to the tailgate 3 via the suspension strut 8 on the first side 6 of the tailgate. In addition, a torque 19 corresponding to the torque 10 is applied to the tailgate 3 via the power strut 9 on the second side 7 of the tailgate 3 during opening of the tailgate.

[0031] During the closing of the tailgate 3, the torque 10 applied by the suspension strut 8 continues to act on the first side 6 of the tailgate 3. During the closing of the tailgate 3, the torque indicated by the arrow 11 acts via the power strut on the second side 7 of the tailgate 3. Since the torques 10 and 11 are directed opposite to each other during the closing of the tailgate, the tailgate 3 is twisted during the closing. This is indicated by the arrow 14. Due to this twisting 14, the closing element 12 located on the tailgate 3 is also twisted relative to the closing element 13 located on the body. This is indicated by the arrow 15.

[0032] Figure 3 The closing device 16 is schematically shown during manual closing of the tailgate 3. In this case, the second closing element 12 engages in the first closing element 13 in order to close the tailgate 3. Figure 3 In the embodiment, the first closing element 13 and the second closing element 12 are oriented symmetrically relative to each other. This is indicated by the axis of symmetry 17. In other words, in Figure 3 In the case shown, the axis of symmetry of the first closing element 13 corresponds to the axis of symmetry of the second closing element 12 during the closing process.

[0033] exist Figure 4 , the closing device 16 is shown in a perspective view during the automatic closing of the tailgate 3. In this case, the axis of symmetry of the second closing element 12 is denoted by the reference numeral 17 and the axis of symmetry of the first closing element 13 is denoted by the reference numeral 18. Due to the twisting 14 of the tailgate 3 during the closing process, the center axes 17 and 18 are offset relative to each other. In other words, an offset occurs between the first and second closing elements. This offset is undesirable and is reduced or preferably completely avoided by means of the invention.

[0034] exist Figure 3 and Figure 4 In the variant of the closure device 16 shown, the first closure element 13 is designed in the form of a latching plate and the second closure element 12 is designed in the form of a fish mouth. In principle, alternative embodiments are possible.

[0035] During the opening of the tailgate 3, for example, a first torque can be applied to the tailgate by the suspension strut, while a second torque is simultaneously applied by the power strut. During the closing process, the first torque of the suspension strut continues to work, while the third torque of the power strut simultaneously acts in the opposite direction. Figure 4 The deflection shown is achieved due to the difference between the first and third torques. For example, a reduction in deflection can be achieved by using a suspension strut 8 with a smaller torque.

[0036] In order to avoid or at least reduce the deviation within the scope of the method according to the invention, the torque of the power strut is reduced as soon as a threshold distance between the first closing element and the second closing element is reached during the closing operation. The threshold distance may be 100 mm, advantageously 70 mm, preferably 40 mm. Due to the reduction of the torque applied by the power strut, the previous distortion of the tailgate 3 is equalized or balanced again shortly before the closing elements engage each other.

[0037] Figure 5 A variant embodiment of the device for closing the tailgate 3 of a motor vehicle 1 according to the invention is schematically shown. The device 4 comprises a suspension strut 8 and a power strut 9. Figure 2 As described, the suspension strut 8 and the power strut 9 are designed to be fastened to the tailgate 3 and the body 2 of the motor vehicle 1. Furthermore, the device 4 comprises a controller 20. The controller 20 is designed in particular to control or regulate the torque applied in particular by the power strut 9 to the tailgate. The device 4 also comprises a closing device 16. The closing device 16 can be, for example, Figure 3 and 4 The closing device can be combined with Figure 2 The device 4 is positioned or fastened as described on the motor vehicle 1 . The device 4 further comprises a device 21 for determining the distance between the first closing element 13 and the second closing element 12 of the closing device 16 .

[0038] The device 4 is designed to reduce the torque applied to the tailgate by the power strut 9 during closing of the tailgate when the distance between the first closing element 13 and the second closing element 12 determined by the device 21 is less than a threshold value. The threshold value can be set, for example, to a distance of 100 mm, advantageously to a threshold value of 70 mm, and preferably to a threshold value of 40 mm.

[0039] The device 4 can be designed in particular to reduce the torque applied to the tailgate by the power strut during the tailgate closing by 90% to 100%, for example to 0 Nm. In this case, the torque reduction is initiated by the controller 20 .

[0040] Figure 6A variant of the method according to the invention is schematically shown in the form of a flow chart. The method starts with step 30, which indicates the start of the method. In step 31, the closing process of the tailgate 3 begins. In step 32, a check is performed to determine whether the distance between the first closing element 13 and the second closing element 12 falls below a set threshold value (e.g. 100 mm, in particular 70 mm or preferably 40 mm).

[0041] If this is not the case, the method is continued in step 31. If this is the case, the torque applied by the power strut 9 is reduced in step 33. For example, the torque can be reduced by 90% to 100%, for example to 0 Nm to 15 Nm. After this, a check is performed in step 34 to determine whether the closing operation has been successfully completed.

[0042] If this is the case, the method ends in step 36. If this is not the case, the closing operation is repeated starting from step 31. Before the method is repeated, the modifications to be implemented in the repetition of the method are set in step 35. For example, it can be set that the threshold value of the distance between the first and second closing elements is to be increased. Alternatively or additionally, it can be set that the torque of the power strut 9 is to be reduced to a greater extent. In this way, the method can be successively adapted to the current situation, for example also to the situation where the motor vehicle 1 is in an inclined position which influences the torque acting on the tailgate 3.

[0043] In yet another variant, the threshold value of the distance between the first closing element 13 and the second closing element 12 can be indicated as a percentage of the entire closing stroke of the tailgate 3 in the region of the closing device. In this case, the torque of the power strut 9 is preferably reduced when the tailgate 3 reaches or exceeds the last 10% (preferably 5%) of the closing stroke.

Claims

1. A method for automatically closing a tailgate (3) of a motor vehicle (1), the motor vehicle (1) comprising a vehicle body (2) and a tailgate closing device (16), wherein the tailgate closing device (16) comprises a first closing element (13) and a second closing element (12), wherein a suspension strut (8) is located on a first side (6) of the tailgate (3), and a power strut (9) is located on a second side (7) of the tailgate (3) opposite to the first side (6), wherein the suspension strut (8) and the power strut (9) are both connected to the tailgate (3) and the vehicle body (2), and wherein the first closing element (13) is located on the tailgate (3) and the second closing element (12) is located on the body (2) of the motor vehicle (1), and the first closing element and the second closing element (12) are designed to engage with each other during closing of the tailgate (3) and to effect the closing of the tailgate (3), Features: During the closing of the tailgate (3), the torque acting on the tailgate (3) via the power strut (9) is reduced before the first closing element (13) engages the second closing element (12).

2. The method according to claim 1, Features: During the closing of the tailgate (3), when the distance between the first closing element (13) and the second closing element (12) is less than 100 millimeters, the torque acting on the tailgate (3) via the power strut (9) is reduced.

3. The method according to claim 1, Features: During the closing of the tailgate (3), when the distance between the first closing element (13) and the second closing element (12) is less than 40 millimeters, the torque acting on the tailgate (3) via the power strut (9) is reduced.

4. The method according to claim 1, Features: During the process of the tailgate (3) closing from 90% to 100%, the torque acting on the tailgate (3) via the power strut (9) is reduced.

5. The method according to claim 1, Features: If the closing process cannot be completed, the closing of the tailgate (3) is repeated, wherein the torque acting on the tailgate (3) via the power strut (9) is reduced to a greater extent than in the previous closing process, and / or the distance between the first closing element (13) and the second closing element (12) when the reduction of the torque acting on the tailgate (3) via the power strut (9) occurs is increased compared to the previous closing process.

6. The method according to claim 1, Features: The first closing element (13) or the second closing element (12) is designed as a latching plate and / or the first closing element (13) or the second closing element (13) has the form of a fish mouth.

7. A device (4) for automatically closing a back door (3) of a motor vehicle (1), wherein the device comprises a suspension strut (8), a power strut (9), a back door closing device (16) and a controller (20), wherein the suspension strut (8) is designed to be arranged on a first side (6) of the tailgate (3) and on a body (2) of the motor vehicle (3), The power strut (9) is designed to be arranged on a second side (7) of the tailgate (3) opposite to the first side (6) and on the body (2) of the motor vehicle (1), The tailgate closing device (16) comprises a first closing element (13) designed to be arranged on the tailgate (3) and a second closing element (12) designed to be arranged on the vehicle body (2), wherein the first closing element (13) and the second closing element (12) are designed to engage with each other during the closing of the tailgate (3) and realize the closing of the tailgate (3), Features: The controller (20) is designed to reduce the torque acting on the tailgate (3) via the power strut (9) before the first closing element (13) engages the second closing element (12) during the closing of the tailgate (3).

8. The device (4) according to claim 7, Features: The controller (20) is designed to reduce the torque acting on the tailgate (3) via the power strut (9) as soon as the distance between the first closing element (13) and the second closing element (12) is less than 100 millimeters during the closing of the tailgate (3).

9. The device (4) according to claim 7, Features: The controller (20) is designed to reduce the torque acting on the tailgate (3) via the power strut (9) as soon as the distance between the first closing element (13) and the second closing element (12) is less than 40 millimeters during the closing of the tailgate (3).

10. The device (4) according to claim 7, Features: The controller (20) is designed to reduce the torque acting on the tailgate (3) via the power strut (9) during the process of the tailgate (3) being closed from 90% to 100%.

11. The device (4) according to claim 7, Features: The controller (20) is designed to repeat the closing of the tailgate (3) if the closing process cannot be completed, wherein the torque acting on the tailgate (3) via the power strut (9) is reduced to a greater extent than in the previous closing process, and / or the distance between the first closing element (13) and the second closing element (12) in the event of a reduction in the torque acting on the tailgate (3) via the power strut (9) is increased compared to the previous closing process.

12. The device (4) according to claim 7, Features: The first closing element (13) or the second closing element (12) is designed as a latching plate and / or the first closing element (13) or the second closing element (13) has the form of a fish mouth.

13. A motor vehicle (1) comprising a tailgate (3), a body (2) and a device (4) according to any one of claims 7 to 12.

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