DRIVER ASSISTANCE SYSTEM AND METHOD FOR COUPLING A TRAILER TO A TOWING VEHICLE

Abstract

A driver assistance system for coupling a trailer to a towing vehicle is described, including a video camera attached to the towing vehicle and an associated display device in the driver's field of vision, in whose video image a static guide marking is displayed along which a coupling mouth arranged on the towing vehicle can be contacted with a drawbar eye held on the trailer by a drawbar. Providing a driver assistance system which helps the driver estimating the three-dimensional position of the drawbar eye in relation to the towing vehicle while rearwards approaching a trailer. The video camera is arranged at a vertical distance from the coupling and the guide marking is formed by two beam corridors arranged on both sides of the vehicle's longitudinal axis converging towards one another in the rearward direction of the towing vehicle.

Claims

1. A driver assistance system for coupling a trailer to a towing vehicle, comprising: a video camera attached to the towing vehicle and an associated display device in the driver's field of vision, in whose video image a static guide marking is displayed along which a coupling mouth arranged on the towing vehicle can be contacted with a drawbar eye held on the trailer by a drawbar, wherein the video camera is arranged at a vertical distance from a coupling and the guide marking is formed by two beam corridors arranged on both sides of the vehicle's longitudinal axis (Z) converging towards one another in the rearward direction of the towing vehicle.

2. The driver assistance system according to claim 1, wherein the beam corridors each have an inner boundary line and an outer boundary line and for a correct coupling a reference element of the drawbar eye is arranged in the video image between the inner boundary line and the outer boundary line of both beam corridors during the approach of the coupling mouth and the drawbar eye.

3. The driver assistance system according to claim 2, wherein the reference element is an outer diameter (Ø.sub.A) of the drawbar eye.

4. The driver assistance system according to claim 2, wherein a distance (a) between the inner boundary line and the outer boundary line of each beam corridor depends on a tolerance range of the coupling mouth and/or the drawbar eye.

5. The driver assistance system according to claim 4, wherein the distance (a) is smaller with increasing distance (D.sub.Z).

6. The driver assistance system according to claim 1, wherein the video camera (10) is arranged in the vehicle longitudinal axis (Z).

7. The driver assistance system according to claim 1, wherein the coupling mouth has a conically expanded wall section and the video camera is arranged above the conically expanded wall section.

8. The driver assistance system according to claim 1, wherein the coupling comprises a connecting flange for mounting on the towing vehicle and a coupling bolt mounted vertically in the coupling mouth, wherein the video camera is arranged in the vehicle longitudinal axis (Z) on the side of the coupling bolt facing away from the connecting flange.

9. The driver assistance system according to claim 1, wherein the coupling has a collision protection plate arranged above the coupling mouth and the video camera is attached behind the collision protection plate.

10. The driver assistance system according to claim 9, wherein the collision protection plate is formed with an opening and the video camera is arranged in alignment with the opening.

11. The driver assistance system according to claim 1, wherein the driver assistance system takes influence automatically or on driver release in the engine control and/or transmission control and/or brake control and/or height control of the air suspension.

12. A method for coupling a trailer to a towing vehicle, with the use of a video camera attached to the towing vehicle and an associated display device arranged in the driver's field of vision, wherein a static guide marking becomes visible in a video image of the display device along which a coupling mouth of a coupling arranged on the towing vehicle is brought into contact with a drawbar eye held on the trailer by a drawbar, wherein the guide marking is visualized by two beam corridors arranged symmetrically to the vehicle longitudinal axis (Z) converging towards one another in the rearward direction of the towing vehicle.

13. The method according to claim 12, wherein the beam corridors each have an inner boundary line and an outer boundary line and during an approach of the coupling mouth and the drawbar eye a correct coupling appears when a reference element of the drawbar eye is arranged in the video image between the inner boundary line and the outer boundary line of both beam corridors.

14. The method according to claim 13, a drawbar eye projecting over both outer boundary lines in the video image visualizes the lifting of the towing vehicle by its air suspension.

15. The method according to claim 13, wherein a drawbar eye arranged in the video image within the two inner boundary lines visualizes the lowering of the towing vehicle by its air suspension.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] For a better understanding, the invention is explained in more detail below with reference to seven figures showing in

[0030] FIG. 1: a side view of a jaw coupling with a video camera in the correct orientation in front of a drawbar eye immediately before coupling;

[0031] FIG. 2: a video image with beam corridors and drawbar eye corresponding to the situation in FIG. 1;

[0032] FIG. 3: a side view of a too low aligned jaw coupling with video camera in front of a drawbar eye immediately before coupling;

[0033] FIG. 4: a video image with beam corridors and drawbar eye corresponding to the situation in FIG. 3;

[0034] FIG. 5: a side view of a too high aligned jaw coupling with video camera in front of a drawbar eye immediately before coupling;

[0035] FIG. 6: a video image with beam corridors and drawbar eye corresponding to the situation in FIG. 5 and

[0036] FIG. 7: a front view of a jaw coupling with a collision protection plate and video camera.

DETAILED DESCRIPTION OF THE INVENTION

[0037] FIG. 1 shows a side view of a jaw coupling 30 and a video camera 10 attached to it. The video camera 10 and a display device 11 shown in FIG. 2 are part of the driver assistance system. The display device 11 is expediently arranged in a driver's cab of a towing vehicle (not shown) and is therefore in the driver's field of vision.

[0038] The jaw coupling 30 comprises a coupling mouth 31 that is open to the rear and a connecting flange 33 for the fixed installation of the jaw coupling 30 on the towing vehicle, in particular on a vehicle frame 38 of the towing vehicle. The coupling mouth 31 is formed with an expanded wall section 32 which completely surrounds an entry opening 37 in the circumferential direction and is open on one side in the axial direction. The video camera 10 is attached in a vehicle longitudinal axis Z (see FIG. 2) above the coupling mouth 31.

[0039] In the illustration of FIG. 1, a drawbar eye 40 attached to the end of a drawbar 41 is in the correct orientation directly in front of the entry opening 37. With the help of the drawbar 41 and the drawbar eye 40, a trailer (not shown) is releasably attached to the towing vehicle. When the towing vehicle travels backwards in direction R, the drawbar eye 40 enters the jaw coupling 30 via the entry opening 37 and, after reaching its end position, is held there pivotably in the jaw coupling 30 by means of a coupling bolt 34.

[0040] Before the trailer is coupled, the coupling bolt 34 is in an open position, which can be achieved by using an operating lever 39. When the jaw coupling 30 comes into contact with the drawbar eye 40, the spring-preloaded coupling bolt 34 snaps down into its closed position and completely penetrates an inner diameter Ø.sub.I of the drawbar eye 40. In its closed position, the coupling bolt 34 runs vertically through the coupling mouth 31 of the jaw coupling 30, which can be seen particularly well in the illustration in FIG. 7, and is supported on opposite sides of the coupling mouth 31.

[0041] The expanded wall section 32 of the coupling mouth 31 makes it easier to pick up a jaw coupling 30 that is not correctly aligned with the drawbar eye 40 and thus expands the tolerance space of the coupling mouth 31. The tolerance space defines an area within which, when the towing vehicle is reversing in direction R, a drawbar eye 40 aligned vertically or laterally offset to the jaw coupling 30 slides into the entry opening 37 by making contact with the expanded wall section 32.

[0042] The scenario illustrated in FIG. 1 is presented to the driver on the display device 11 in a video image 20 transmitted by the video camera 10 according to FIG. 2. In the video image 20, the rear area behind the towing vehicle and the drawbar eye 40 of the trailer to be coupled are shown. The jaw coupling 30 is not shown in the video image 20 because it is located outside an area captured by the video camera 10.

[0043] For an estimation of the relative position of the drawbar eye 40 to the towing vehicle, a guide marking 21 in the form of two beam corridors 22 tapering in the rearward direction is shown on the display device 11. The two beam corridors 22 are aligned symmetrically to one another with respect to the vehicle longitudinal axis Z, with one of the beam corridors 22 being arranged on one side of the vehicle longitudinal axis Z in each case. Each beam corridor 22 has an inner boundary line 23 facing the other beam corridor 22 and an outer boundary line 24 facing away from the other beam corridor 22. The inner boundary line 23 is spaced apart from the outer boundary line 24 at a distance a perpendicular to it. The distance a decreases with increasing distance D.sub.Z from the video camera 10 in the longitudinal axis Z of the vehicle.

[0044] The alignment of the beam corridors 22 and the distance a, as a reference element of the trailer, are matched to the known, usually standardized size, the drawbar eye 40, in the present case to its outer diameter Ø.sub.A, since this can be seen better in the video image 20 than the inner diameter Ø.sub.I. In principle, however, the inside diameter Ø.sub.I or another reference element arranged in a stationary manner on the trailer could also be used and, if necessary, an offset to the position of the drawbar eye 40 could be applied.

[0045] The beam corridors 22 visualize the driver during the reverse drive R a correct alignment of the jaw coupling 30 to the drawbar eye 40, as long as the reference element, for example, the outer diameter Ø.sub.A of the drawbar eye 40 covers both beam corridors 22 such that in each beam corridor 22 a section of the outer diameter Ø.sub.A between the inner boundary line 23 and the outer boundary line 24 is arranged. In reverse direction R, the driver maneuvers the towing vehicle in such a way that a section of the outer diameter Ø.sub.A is held between the inner boundary line 23 and the outer boundary line 24 in both beam corridors 22. As the towing vehicle approaches the stationary trailer in the longitudinal axis Z of the vehicle, the image of the drawbar eye 40 and thus also its outer diameter Ø.sub.A in the video image 20 increases in the same way as the size of the beam corridors 22. If the drawbar eye 40 leaves the lower edge of the video image 20, the driver can estimate that contact between the coupling mouth 31 and the drawbar eye 40 occurs immediately.

[0046] FIG. 3 to FIG. 6 illustrate situations in which the towing vehicle is in the center of the vehicle's longitudinal axis Z in front of the drawbar eye 40, but the height adjustment of the air suspension is incorrectly set and, when the towing vehicle approaches, the drawbar eye 40 moves over the coupling mouth 31 or passes under the coupling mouth 31 and would therefore cause severe damage to the towing vehicle.

[0047] In a side view, FIG. 3 shows a too low, vertical position of the jaw coupling 30. For a correct retraction of the drawbar eye 40 into the coupling mouth 31, the towing vehicle would have to be raised by means of the air suspension.

[0048] The drawbar eye 40 is located relatively close to the video camera 10, so that the drawbar eye 40 is shown larger in the video image 20 according to FIG. 4 than the static, always equally sized beam corridors 22. The outer diameter Ø.sub.A protrudes beyond both, the inner boundary line 23 and the outer boundary line 24, of both beam corridors 22. To continue the coupling, the towing vehicle would have to be raised by means of its air suspension until a larger vertical distance is established between the video camera 10 so that in the video image 20 the outer diameter Ø.sub.A of the drawbar eye 40 has moved between the inner boundary line 23 and the outer boundary line 24 of both beam corridors 22.

[0049] In a side view, FIG. 5 shows a too high, vertical position of the jaw coupling 30. For a correct entering of the drawbar eye 40 into the coupling mouth 31, the towing vehicle would have to be lowered by means of the air suspension.

[0050] The drawbar eye 40 is located in a relatively distant position from the video camera 10, so that in the video image 20 of FIG. 6 the drawbar eye 40 is shown smaller than the static, always equally sized beam corridors 22. The outer diameter Ø.sub.A is arranged between the beam corridors 22 and just extends as far as the inner boundary lines 23. To continue the coupling, the towing vehicle would have to be lowered by means of its air suspension until a smaller vertical distance is established between the video camera 10 and the drawbar eye 40 so that the outer diameter Ø.sub.A in the video image 20 has moved between the inner boundary line 23 and the outer boundary line 24 of both beam corridors 22.

[0051] FIG. 7 shows a jaw coupling 30 in a front view. A collision protection plate 35 is attached vertically above the coupling mouth 31. The collision protection plate 35 covers parts of the locking mechanism and in particular the operating lever 39 in the vehicle longitudinal axis Z from the rear, in order to avoid damage caused by the drawbar eye 40 during coupling of the trailer if the jaw coupling 30 is set too low.

[0052] In the vehicle longitudinal axis Z, the collision protection plate 35 projects beyond the expanded wall section 32 towards the rear, so that the video camera 10 is positioned essentially above the free end of the expanded wall section 32.

[0053] In the longitudinal axis Z of the vehicle, an opening 36 is formed in the collision protection plate 35, behind which the video camera 10 is aligned. The opening 36 is dimensioned in such a way and the video camera 10 is spaced from the opening 36 in such a way that the known outer diameter Ø.sub.A of the drawbar eye 40 cannot penetrate so far into the opening 36 that the video camera 10 is contacted and damaged, even if the drawbar eye 40 hits with a great force against the collision protection plate 35.

LIST OF REFERENCE NUMBERS

[0054] 10 video camera [0055] 11 display device [0056] 20 video image [0057] 21 guide marking [0058] 22 beam corridors [0059] 23 inner boundary line of beam corridor [0060] 24 outer boundary line of beam corridor [0061] 30 coupling/jaw coupling [0062] 31 coupling mouth [0063] 32 expanded wall section [0064] 33 connecting flange [0065] 34 coupling bolt [0066] 35 collision protection plate [0067] 36 opening protection plate [0068] 37 entry opening [0069] 38 vehicle frame towing vehicle [0070] 39 operating lever [0071] 40 drawbar eye [0072] 41 drawbar [0073] a distance inner/outer boundary line [0074] D.sub.Z distance in the vehicle's longitudinal axis [0075] R reversing towing vehicle [0076] Z vehicle longitudinal axis [0077] Ø.sub.A outer diameter of drawbar eye [0078] Ø.sub.I inner diameter of drawbar eye