Abstract
In a measuring device for measuring an articulation angle between a tractor vehicle which has a longitudinal axis, and a trailer which has a longitudinal axis, with a trailer coupling which trailer coupling includes a coupling ball, a ball receptacle which serves to receive the coupling ball, and at least one magnetic sensor it is proposed that the coupling ball have a ball opening, that a magnet be mounted in the ball opening, and that the ball receptacle have a recess, and that the at least one magnetic sensor be mounted in the recess, wherein changes in a magnetic field generated by the magnet are sensed by the magnetic sensor.
Claims
1-15. (canceled)
16. A measuring device for measuring an articulation angle between a tractor vehicle having a first longitudinal axis and a trailer having a second longitudinal axis, the tractor vehicle and the trailer being coupled by a trailer coupling having a coupling ball and a ball receptacle adapted to receive the coupling ball, the measuring device comprising: a magnet mounted in a ball opening of the coupling ball; and at least one magnetic sensor mounted in a recess of the ball receptacle and adapted to detect changes in a magnetic field produced by the magnet; wherein a center of the magnet and a hinge center of the trailer coupling which defines a center of rotation have at least approximately a same position, such that the articulation angle is measured independently of tilting movements and rotations which occur about at least one of the first longitudinal axis and the second longitudinal axis.
17. The measuring device according to claim 16, wherein at least one of: the ball opening is a bore that passes completely or partially through the coupling ball; and the recess is a bore.
18. The measuring device according to claim 16, wherein: a third longitudinal axis extends between magnetic poles of the magnet and parallel to the first longitudinal axis of the tractor vehicle; and the magnet is aligned with the third longitudinal axis.
19. The measuring device according to claim 16, wherein dimensions of the magnet and a position of the magnet within the ball opening are such that a space remains between the poles of the magnet and an outer surface of the coupling ball.
20. The measuring device according to claim 16, wherein at least one of: the magnet and the ball opening have mutually corresponding threaded elements so that the magnet can be screwed into the ball opening; and a filler is provided inside the ball opening which holds the magnet and/or seals the ball opening.
21. The measuring device according to claim 16, wherein the coupling ball consists of a diamagnetic or paramagnetic material.
22. The measuring device according to claim 16, wherein the coupling ball and/or the ball receptacle comprises stainless steel.
23. The measuring device according to claim 16, wherein the recess of the ball receptacle has a fourth longitudinal axis which extends radially to a center of the coupling ball.
24. The measuring device according to claim 16, wherein the at least one magnetic sensor is arranged in such a way that, with coaxial alignment of the first and second longitudinal axes of the tractor vehicle and of the trailer, it is at least approximately equidistant from both poles of the magnet.
25. The measuring device according to claim 16, wherein the at least one magnetic sensor are two magnetic sensors which are each arranged in a recess of the ball receptacle.
26. The measuring device according to claim 16, wherein the at least one magnetic sensor is a Hall sensor.
27. A vehicle combination, comprising a tractor vehicle and a trailer, having a measuring device according to claim 16, wherein the at least one magnetic sensor is connected to a control unit, that the output signals of the magnetic sensor can be processed in the control unit using a control program, and at least one actuator can be actuated as a function of the measured articulation angle, and that the actuator is coupled via a force transmission unit to wheels of the tractor vehicle and/or trailer, or brake devices connected thereto.
28. The vehicle combination according to claim 27, wherein at least one pair of the wheels of the tractor vehicle and/or trailer is steerably suspended and controllable by means of the at least one actuator.
29. The vehicle combination according to claim 27, wherein at least one of the wheels of the trailer is assigned an individually actuatable braking device, that the braking device can be controlled by means of the at least one actuator.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0054] In the following, the invention is explained in more detail by reference to the drawings, wherein:
[0055] FIG. 1a shows a measuring device according to the invention for measuring an articulation angle with a trailer coupling 9 comprising a coupling ball 21 and a ball receptacle 11;
[0056] FIG. 1b shows the device of FIG. 1a illustrated from the other side with a magnetic sensor 4, by means of which changes of a magnetic field are measurable during the rotation of the coupling ball 21, which magnetic field is generated by a magnet 3 (see FIG. 3a), which is embedded in the coupling ball 21;
[0057] FIG. 1c shows a trailer 1 according to the invention, which is connected via a trailer coupling 9 according to FIG. 1a to a tractor vehicle 2 shown schematically as an arrow;
[0058] FIG. 2 shows the measuring device of FIG. 1a schematically illustrated in a preferred embodiment with the coupling ball 21, in which a cylindrical magnet 3 is arranged, and with the ball receptacle 11, in which optionally two magnetic sensors 4A, 4B are arranged, the output signals of which are transmitted to a control device 12 of the trailer 1;
[0059] FIG. 3a shows a longitudinal section through the measuring device and the trailer coupling 9 along the intersection line A--A of FIG. 1b with a view to an inclination plane eN in which the coupling ball 21 is rotatable relative to the ball receptacle 11 without changing the distance between the poles S, N of the magnet 3 and the magnetic sensor 4;
[0060] FIG. 3b shows a cross-section through the measuring device and the trailer coupling 9 along the intersection line B--B of FIG. 1b with a view to a torsion plane eT, in which the coupling ball 21 is rotatable relative to the ball receptacle 11 without changing the distance between the poles S, N of the magnet 3 and the magnetic sensor 4;
[0061] FIG. 3c shows a cross-section through the measuring device and the trailer coupling 9 along the intersection line C--C of FIG. 1a with a view to a rotation plane eK in which the coupling ball 21 is rotatable with respect to the ball receptacle 11, wherein the distance between the poles S, N of the magnet 3 and the magnetic sensor 4 changes and the articulation angle resulting from the rotation can be detected; and
[0062] FIG. 4 shows the trailer 1 and the tractor vehicle 2 of FIG. 1c shown schematically as an arrow, which trailer and tractor vehicle enclose an articulation angle wK with their longitudinal axes xT and xZ.
DETAILED DESCRIPTION
[0063] FIG. 1a shows a measuring device according to the invention for measuring an articulation angle with a trailer coupling 9, which includes a coupling ball 21 held by a ball carrier 29 and a ball receptacle 11 held by a receptacle carrier 19. Trailer couplings 9 of this type, which are manufactured, for example, by Scharmller GmbH & CoKG, AT-4892 Fornach, e.g. the trailer coupling K 80, allow any tractor vehicle and trailer to be connected in an articulated manner.
[0064] FIG. 1b shows the device of FIG. 1a from the other side with a magnetic sensor 4 inserted into the coupling receptacle 11, by means of which changes of the magnetic field can be measured during the rotation of the coupling ball 21 or the ball receptacle 11, which is generated by a schematically shown magnet 3 embedded in the coupling ball 21. The magnetic sensor 4, which is held in a recess 10 of the ball receptacle 11, as shown as an example in FIG. 3b, is a Hall sensor of the above mentioned type S12-AH-RGCD3, for example.
[0065] As shown in FIG. 1c and FIG. 4, for example, the ball receptacle 11 is rigidly connected to a trailer 1 and the coupling ball 21 with the ball carrier 29 is rigidly connected to the tractor vehicle. The longitudinal axes xZ and xT of tractor vehicle 2 and trailer 1, which are at least approximately coaxial with each other when the vehicle combination travels along a flat and straight road, are shown. When driving along a flat road but along a curve, only the articulation angle wK changes according to the curve radius, as shown in FIG. 4. This means that the parts of the trailer coupling 9 are rotated within a horizontal plane. When driving along a straight road whose gradient changes, the angle of inclination changes, i.e. the parts of the trailer coupling 9 are twisted in a vertical plane. When driving on a straight road without gradient changes, but with alternating unevenness, e.g. potholes, the parts of the trailer coupling 9 may rotate axially in some cases. The described rotations of the trailer coupling 9 often occur in combination.
[0066] In the preferred embodiment of the measuring device according to the invention shown here, changes in the magnetic field are only generated if there is a change in the articulation angle of the trailer coupling. The magnetic sensor and its output signal are not affected by any rotations of the trailer coupling about its longitudinal axis or by any mutual inclination of the parts of the trailer coupling in the event of a change in inclination. These movements which are not taken into account in the measurement can, however, be detected in a similar way using additionally installed magnets 3 and magnetic sensors 4, if desired.
[0067] The measured articulation angle or the output signal of the magnetic sensor 4 can be advantageously evaluated and used in various ways in tractor vehicle 2 or in trailer 1. In the tractor vehicle, for example, abnormal changes in the articulation angle can be displayed, e.g. to signal an undesirable driving behavior to the driver on a display. In trailer 1, the output signal of the magnetic sensor 4 can be used to control the wheels 16 according to the measured articulation angle wK. As shown in FIG. 4, the two wheels of trailer 1 are rotated by a steering angle wS. With this control, trailer 1 exactly follows the track of the tractor vehicle. In particular, if there are excessive changes in the articulation angle wK, the brakes, which are individually assigned to the wheels 16, can also be acted on advantageously.
[0068] For this purpose, a control device 12, in which the output signal of the magnetic sensor 4 is processed by means of an application program 121, as shown for example in FIG. 2, and corresponding control signals are output to at least one actuator or actuator 13, which acts via transmission lines 14, electrical or hydraulic lines or rod assemblies on mechanical or electrical devices which are provided for individual or paired braking or control of the wheels, is provided for this purpose in trailer 1 on a chassis 18. As mentioned above, the solution according to the invention can be used with different vehicles that have different technical systems that can preferably be influenced as a function of the measured articulation angle.
[0069] FIG. 2 shows the measuring device of FIG. 1a in a schematic representation with the coupling ball 21, in which a cylindrical magnet 3 is arranged, and with the ball receptacle 11, in which optionally two magnetic sensors 4A, 4B are arranged, the output signals of which are transmitted via measuring lines 40A, 40B to the control device 12 of the trailer 1. By using two magnetic sensors 4A, 4B the measurement of the articulation angle wK is redundant. If one magnetic sensor 4A or 4B fails, the output signals of the other sensor 4B or 4A can be used. It is also advantageous to compare the output signals of both magnetic sensors 4A, 4B in order to check the condition of the measuring device.
[0070] It is shown that the magnet 3 is formed cylindrically and has two poles S, N which are pierced by the longitudinal axis xML of the magnet 3. The equatorial plane eME of the magnetic field, which runs perpendicular to the longitudinal axis xML of magnet 3 and through the center 3M between the two poles S, N of magnet 3, is also indicated.
[0071] The longitudinal axis xML of the magnet 3 extends coaxially to the longitudinal axes of the cylindrical magnetic sensors 4A, 4B at the given articulation angle. The first magnetic sensor 4A delivers a voltage of 5V and the second magnetic sensor 4B delivers a voltage of 0V. This alignment of the magnet 3 preferably occurs after mutual rotation of the coupling ball 21 and the ball receptacle 11 by 90.
[0072] In FIGS. 3a, 3b and 3c, in which the coupling ball 21 and the ball receptacle 11 are shown in section, the longitudinal axes xZ and xT of tractor vehicle 2 and trailer 1 are aligned coaxially to each other.
[0073] FIG. 3a shows a longitudinal section through the measuring device and the trailer coupling 9 along the intersection line A--A of FIG. 1b with a view to an inclination plane eN, in which the coupling ball 21 is rotatable relative to the ball receptacle 11 without changing the distance between the poles S, N of the magnet 3 and the magnetic sensor 4.
[0074] FIG. 3a shows that the coupling ball 21 has a cylindrical ball opening 20 in which the cylindrical magnet 3 is mounted. The ball opening 20 is a bore which passes through the coupling ball 21 completely or partially. If the ball opening 20 is closed on one side, the magnet 3 can be pushed into the coupling ball 21 up to a stop. If the ball opening 20 completely penetrates the coupling ball 21, the magnet 3 is preferably pushed in until the center of the magnet 3 lies at the center of the coupling ball 21. As mentioned above, the magnet 3 and the ball opening 20 can be provided with threaded elements that allow the magnet 3 to be screwed into a desired position. Alternatively or additionally, the remaining space next to the poles S, N of magnet 3 can be filled with a filler 6, such as a casting compound, a resin or an adhesive, to fix magnet 3 and seal the ball opening 20 tightly on one or both sides.
[0075] As this is shown, a magnet 3 is preferably selected, which does not fully fill the ball opening 20 in the direction of the longitudinal axis. This prevents the field lines 30 of the magnetic field from entering deep into the metal ball receptacle 11 and the magnetic field from being changed undesirably. Preferably it is also prevented that the field lines 30 of the magnetic field within the coupling ball 21 are short-circuited and cannot emerge from the coupling ball 21. The coupling ball 21 is preferably made of a diamagnetic or paramagnetic material with a low permeability value r.
[0076] The magnet 3 is embedded in the coupling ball 21 in such a way that its longitudinal axis xML extends coaxially or axially parallel to the longitudinal axis xZ of the tractor vehicle 2. The magnetic sensor 4 is aligned with its longitudinal axis xS perpendicularly to the longitudinal axis xML of the magnet 3. Preferably, the longitudinal axis xS or measuring axis of the magnetic sensor 4 lies in the equatorial plane eME of the magnet 3 and runs through its magnetic center 3M, as shown by way of example in FIG. 2.
[0077] In this center position, the Hall sensor 4 used in this case delivers a center voltage of 2.5V via a sensor cable 40. If the coupling ball 21 is rotated in the intersection plane or the inclination plane eN relative to the ball receptacle 11, the magnetic sensor 4 remains aligned to the same equator point. The output voltage of the magnetic sensor 4 therefore does not change during this rotation. If the coupling ball 21 is rotated with the magnet 3 about the common longitudinal axis xML or xZ, the magnetic sensor 4 extends along the equator of the magnetic field, which is why in this case too there is no change in the output voltage of the magnetic sensor 4.
[0078] FIG. 3b shows a cross-section through the measuring device and the trailer coupling 9 along the intersection line B--B of FIG. 1b with a view to a torsion plane eT, in which the coupling ball 21 can be rotated relative to the ball receptacle 11 without changing the distance between the poles S, N of the magnet 3 and the magnetic sensor 4. If the coupling ball 21 is rotated with the magnet 3 about the common longitudinal axis xML or xZ, or if the coupling ball 21 is rotated in the torsion plane eT relative to the ball receptacle 11, the magnetic sensor 4 extends along the equator of the magnetic field, which is why in this case also no field change is detected and no change in the output voltage of the magnetic sensor 4 occurs.
[0079] FIG. 3c shows a cross-section through the measuring device and the trailer coupling 9 along the intersection line C--C of FIG. 1a with a view to a normally horizontally aligned rotation plane eK, in which the coupling ball 21 is rotatable relative to the ball receptacle 11, wherein the distance between the poles S, N of the magnet 3 and the magnetic sensor 4 changes and the articulation angle wK resulting from the rotation can be measured. If the coupling ball 21 is rotated by +90, the north pole N is located opposite the magnetic sensor 4, which delivers a voltage of 0V. If the coupling ball 21 is rotated by 90, the south pole S is located opposite the magnetic sensor 4, which delivers a voltage of 5V. This means that articulation angles from +90 to 90 can be measured continuously.
[0080] FIG. 4 shows trailer 1 and the tractor vehicle 2 of FIG. 1c shown schematically as an arrow, which with their longitudinal axes xT and xZ enclose an articulation angle wK, according to which the wheels 16 were turned around the steering angle wS. This steering angle wS was selected so that trailer 1 follows the track of tractor vehicle 2. The steering angle wS can also be provided with an offset or deviation, e.g. in inclined terrain or at higher speeds, to compensate for lateral displacements. The wheels 16 of trailer 1 are equipped with a wheel suspension 15 for steerable wheels, as described for example in EP0193796A1. Alternatively or additionally, each wheel 16 can be assigned a braking device 17 which can be controlled by the control device 12 as well as an actuator 13 and a transmission line 14.
