Coupling device for a vehicle at the rear in the direction of travel of a vehicle train.

Abstract

Coupling device (2) for a vehicle (4) located at the rear in the direction of travel (A) of a vehicle train (3, 4), with a coupling eye (21) with a coupling eye bushing (22) whose coupling eye (23) extends along a longitudinal axis (X'), characterized by at least one wear detection means (6), preferably arranged centrally along the longitudinal axis (X'), which is aligned perpendicular to the longitudinal axis (X') and is arranged at least in the coupling eyelet bushing (22) such that wear of the coupling eyelet bushing (22) perpendicular to the longitudinal axis (X') can be detected optically and / or sensorially.

Description

[0001] The present invention relates to a coupling device for a rear vehicle of a vehicle combination in the towing direction according to the preamble of patent claim 1, a coupling eye bushing for use in a coupling eye of such a coupling device according to patent claim 13, a rear vehicle with such a coupling device according to patent claim 14 and a vehicle combination with such a rear vehicle according to patent claim 15.

[0002] In order to enable a towing vehicle to tow a trailer, the towing vehicle and the trailer must be connected to one another in a power-transmitting and detachable manner. Such towing vehicles can be, for example, a passenger car, a truck, a bus, a construction machine, a forestry or agricultural vehicle, a military vehicle or another land vehicle, in particular another road vehicle or off-road vehicle. Such towing vehicles can be moved or driven by means of their own drive, i.e. they can be vehicles with their own drive. A towing vehicle can move with it or pull behind it at least one trailer as a vehicle without its own drive. A trailer is usually used to transport loads and can be, for example, a car trailer, a truck trailer, a caravan, a horse trailer, a boat trailer and the like.Trailers have at least one axle with wheels and often at least two axles with wheels. Trailers can also be designed for private, recreational, or commercial use, for example, in the freight forwarding, construction, agriculture, and the like. The towing vehicle and trailer can also be referred to collectively as a vehicle combination. The towing vehicle can also be referred to as the front vehicle in the direction of towing, travel, or movement, and the trailer can also be referred to as the rear vehicle in the direction of towing, travel, or movement.

[0003] A detachable connection between the towing vehicle and trailer is typically achieved using a so-called trailer coupling for attaching the trailer to the towing vehicle. This coupling consists of at least two parts and has a coupling device on each of the towing vehicle and the trailer, which are held there and can be detachably connected to one another. Multiple trailers can also be detachably connected to one another in this way.

[0004] Various types of trailer couplings are known, such as bolt couplings and jaw couplings or bolt coupling systems and jaw coupling systems, in which a shaft or drawbar extends from the trailer to the towing vehicle and has an eyelet at the end as a through-opening in the vertical direction, which can also be referred to as a towing eye or coupling eye. The towing eye or coupling eye can have a bushing as a coupling eye bushing, which can be manufactured separately and pressed into a corresponding recess in the coupling eye so that it can be replaced as a wearing part without having to replace the entire coupling device. At the opposite end, the shaft is designed, for example, as a flange and is fixedly attached to the trailer frame by means of screws.

[0005] On the towing vehicle side, a bolt coupling has a bracket fixedly attached to the frame of the towing vehicle. This bracket has two vertical surfaces, each with a through-hole in the vertical direction. The two through-holes are aligned with each other. The trailer's towing eye can be accommodated between the two surfaces of the towing vehicle bracket. All three through-holes can be connected vertically by a bolt, also called a coupling bolt, which rests on the upper surface by means of a thickened portion and can be secured at the lower end. This can be done in a similar way with a jaw coupling or a jaw coupling system.

[0006] From AT 412 268 B, a drawbar eye of a coupling is known with a coupling element, in particular comprising a ring, a ball socket or the like, a spacer element and a flange with corner regions having a substantially rectangular, in particular substantially square, base area.

[0007] With such trailer couplings, for example, a certain distance of a few millimeters must be maintained between the inner diameter of the towing eye or coupling eye socket of the trailer drawbar and the outer diameter of the coupling bolt of the towing vehicle in order to ensure a positive connection. This results in play, particularly in the longitudinal direction, which is the main direction of travel, movement, or pulling. While this is necessary for connecting or coupling, it allows a certain amount of relative movement during travel, essentially in the direction of travel, movement, or pulling, between the towing vehicle and the trailer, or between the coupling bolt and the towing eye or coupling eye socket.

[0008] The disadvantage of this play between the coupling pin and the towing eye or coupling eye bushing during operation is that the towing eye or coupling eye bushing and the coupling pin can rub against each other and / or collide, resulting in abrasion or wear on these components due to the forces present. Over time, this mechanical wear can not only reduce the material thickness of both the coupling pin and the towing eye or coupling eye bushing, thereby weakening the coupling pin or towing eye or coupling eye bushing as a transmission element in the power flow between the trailer and towing vehicle, but can also increasingly increase the play, which can then lead to greater relative movements and resulting stronger forces with increasing mechanical wear.

[0009] Therefore, to ensure road safety, it is necessary to check the towing eye and coupling eye bushing for wear on a regular basis, for example at specific intervals such as every six months or depending on the trailer's use, e.g. the number of kilometres driven. This has currently been done manually, i.e. by a person who uses a mechanical gauge or template to measure the dimensions of the towing eye or coupling eye bushing at specific, specified points in order to determine whether the measured dimensions still meet the relevant specifications, i.e. whether the towing eye or coupling eye bushing is already excessively worn and needs to be replaced or not.

[0010] The disadvantage of this is that the assessment of permissible or impermissible wear on the towing eye or coupling eye bushing is left to the individual concerned, resulting in a certain degree of uncertainty, as the assessment may also depend on the attentiveness and / or experience of the person making the assessment. This can lead to the continued use of an excessively worn towing eye or coupling eye bushing, which can endanger the roadworthiness of the trailer. It can also lead to the premature replacement of a still-usable towing eye or coupling eye bushing, which can cause additional effort, additional costs, and / or unnecessary trailer downtime.

[0011] Another disadvantage is that wear on the trailer's drawbar eye or coupling eye bushing can vary greatly, meaning that within the permissible time or mileage interval between two wear tests, excessive wear can be reached without being detectable at the time. This can also endanger the trailer's roadworthiness.

[0012] EP 3 421 272 A1 describes a trailer coupling for connecting a trailer to a towing vehicle. The trailer coupling comprises a wearable support element arranged to bear against a connecting portion of a drawbar mounted on the trailer when the connecting portion, i.e. the towing eye, is received by the coupling receptacle of the trailer coupling and positioned in a towing position. The trailer coupling also comprises a movable coupling element, i.e. a coupling pin, having a first position such that the connecting portion, i.e. the towing eye, can move into and out of the towing position, and a second position for securing the connecting portion, i.e. the towing eye, in the towing position, the second position being such that the connecting portion, when entering and out of the towing position, urges the coupling element, i.e. the coupling pin, to move.The trailer coupling further includes a size sensor configured to provide a measurement indicative of a magnitude of movement and thereby capable of detecting when the amount of wear on the support member exceeds a predetermined threshold. Thus, the wearable support member of the coupling receptacle of the towing vehicle's trailer coupling is monitored for wear, but not the coupling pin or the drawbar eye.

[0013] KR 10 1 411 635 B1 describes a tow hook device for a vehicle with a wear indicator comprising a fastening unit which is installed in the front body of a vehicle and fastened to the body, an annular head unit which is connected to the fastening unit, a first display unit which is formed on the head unit, and a second display unit which is adjacent to the first display unit and has a ruler.

[0014] An object of the present invention is to provide a coupling device for a vehicle located at the rear in the direction of towing of a vehicle combination of the type described above, so that the inspection of wear on the coupling device can be simplified and / or improved. In particular, the wear on the coupling device should be able to be monitored more regularly than before and, in particular, even continuously. This should be made possible in particular for a coupling eye bushing of a coupling eye of the coupling device of a vehicle located at the rear in the direction of towing. This should, in particular, be able to be carried out as simply, reliably, space-savingly, independently of personnel and / or automatically as possible. In any case, the road safety of the trailer should, in particular, be improved or increased.At least an alternative to known methods for checking the wear of the coupling device of a vehicle located at the rear in the direction of travel should be created.

[0015] The object is achieved according to the invention by a coupling device having the features of patent claim 1, by a coupling eye bushing having the features of patent claim 13, by a rear vehicle having the features of patent claim 14, and by a vehicle assembly having the features of patent claim 15. Advantageous further developments are described in the subclaims.

[0016] The present invention therefore relates to a coupling device for a rear vehicle in the direction of towing of a vehicle combination, having a coupling eye with a coupling eye bushing, the coupling eye of which extends along a longitudinal axis. The coupling eye bushing of the coupling eye or the towing eye or the coupling eye itself represents, as described above, an annular, rotationally symmetrical and usually metallic through-opening into which the corresponding coupling bolt of a front vehicle in the direction of towing of the vehicle combination can engage vertically from above. The longitudinal axis of the coupling eye bushing or of the coupling eye as its axis of rotational symmetry coincides, when used on a trailer, with the axis of the vertical direction in Cartesian coordinates, i.e. with the direction of gravity, which extends perpendicular to the horizontal plane.

[0017] The coupling device according to the invention is characterized by at least one wear detection means arranged at least in the coupling eye bushing, oriented perpendicular to the longitudinal axis, such that wear of the coupling eye bushing perpendicular to the longitudinal axis can be detected optically and / or by sensors. In other words, a wear detection means is arranged within the contour or within the material of the coupling eye bushing such that both the material of the coupling eye bushing and the material of the wear detection means are reduced in their radial extent by the abrasion or wear that occurs on the part of the coupling eye bushing during operation, as described above.

[0018] For this purpose, the at least one wear detection means can be arranged exactly radially or perpendicularly to the longitudinal axis or at least obliquely to the longitudinal axis in the coupling eyelet bushing so that the abrasion or wear can also reduce the wear detection means from the outside.

[0019] The present invention is based on the finding that by designing a part of the coupling eye bushing as or with a wear detection means, the extent of abrasion or wear of the coupling eye bushing at this point can be made visually visible from the outside and / or detectable by sensors. In any case, the condition of the wear detection means can be detected and monitored more easily in this way than was previously possible through regular manual inspections of the coupling eye bushing itself as described above. This can reduce the effort and thus also the cost of checking the extent of wear on the coupling eye bushing. This can also increase the reliability of the inspection result, which can firstly increase the road safety of the trailer in the vehicle combination and secondly avoid premature or unnecessary replacement of a still-usable coupling eye bushing.Placing the wear detection device within the coupling eye bushing can minimize implementation costs and, in particular, the required installation space. In particular, continuous and significantly more regular inspection and monitoring of the degree of wear on the coupling eye bushing can be performed than previously possible, which can increase the road safety of the trailer in the vehicle combination and extend the service life of the coupling eye bushing.

[0020] Preferably, the wear detection means is arranged in at least one horizontal cavity of the coupling eye bushing, wherein the wear detection means comprises at least one first wear element of a first color, which is arranged between the outer edge of the horizontal cavity and a wear limit. The first color of the wear element differs significantly from the color of the material of the coupling eye bushing itself. In other words, at least one colored wear element, in particular made of a colored plastic, can be used as the wear detection means. This wear element can be introduced into a corresponding cavity of the coupling eye bushing and is flush with the contour or surface of the coupling eye bushing on the outside and can be visually recognized by a person.If the colored wear element is not yet completely worn away, the colored wear element can be visually identified by the person and from this, the permissible wear of the coupling eye bushing can be concluded. If the colored wear element is no longer visually identified by the person, the person can conclude that the colored wear element is completely worn away and thus the limit of permissible wear has been reached or exceeded. This can represent a particularly simple implementation of the present invention, which can allow a person to regularly visually check for wear. In particular, the driver of the towing vehicle who is to couple a trailer can easily and quickly visually check the wear condition of the trailer's coupling eye bushing. This can increase the driver's confidence in using a foreign or unknown trailer.

[0021] The wear detection means may also comprise at least two differently colored wear elements arranged radially one behind the other in order to increase the informative value, as will be described in more detail below.

[0022] Alternatively or additionally, the wear detection means can enable electronic monitoring of the wear condition or wear limit of the coupling eye bush, as will be described in more detail below.

[0023] In any case, the wear detection device can be arranged at a location in the horizontal plane or in the cross-section of the coupling eye bushing where particularly significant abrasion or wear typically occurs, or where excessive wear is typically expected to first occur. This can increase the informative value of the wear detection device accordingly. For this purpose, the wear detection device can be arranged centrally along the longitudinal axis, in particular.

[0024] It is also possible, viewed in the horizontal plane or in the cross-section of the coupling eye bushing, to use several identical or different wear detection means in order to be able to implement the previously described wear control at a corresponding number of points on the coupling eye bushing. This makes it possible, in particular, to monitor several points which are normally subject to significant wear simultaneously for wear as described above. In this case, for example, at least one sensory wear detection means can be used at a point on the coupling eye bushing which is difficult or not at all to detect visually for the person or the driver. At least one optical wear detection means can be used at a point on the coupling eye bushing which is easy or readily visible for the person or the driver.

[0025] Several identical or different wear detection devices can also be arranged offset from one another in the vertical direction, i.e., along the longitudinal axis, in order to monitor different sections of the coupling eye bushing and / or multiple locations within a section of the coupling eye bushing as described above, as will be described in more detail below. This can also increase the informative value of the wear detection devices accordingly.

[0026] In any case, the wear detection means can advantageously be completely accommodated in the coupling eye bushing, so that the rest of the coupling device remains unchanged and can be further developed into a coupling device according to the invention by using a coupling eye bushing according to the invention. A worn coupling eye bushing can also be replaced along with the worn wear detection means.

[0027] According to one aspect of the invention, the wear detection means is arranged in at least one horizontal cavity of the coupling eye bushing, wherein the wear detection means has at least one first wear element of a first color, which is arranged between the inner edge of the horizontal cavity of the coupling eye bushing and a wear limit, and at least one second wear element of a second, different color, which is arranged within the wear limit. In this way, the first color of the first wear element can be recognized by the person or the driver, and permissible wear of the coupling eye bushing can be concluded. If the person or the driver visually recognizes the second color of the second wear element, this can be concluded that impermissible wear of the coupling eye bushing.

[0028] Thus, as a further development of the previously described single colored wear element, the optically detected second color of the second wear element can be used to infer that the second wear element is still present. If only a first colored wear element were used, its absence could be due to either the permissible wear limit being reached or the single-colored wear element having become loose and fallen out of the coupling eye bushing. In this case, a still-usable coupling eye bushing would be considered worn and unnecessarily replaced. This can be avoided by this aspect of the invention.

[0029] According to a further aspect of the invention, the wear detection means comprises at least one illuminant, which is arranged within the horizontal cavity of the coupling eyelet bushing and / or within a cavity of the coupling eyelet, preferably within an annular cavity of the coupling eyelet, and is designed to illuminate the first wear element through the second wear element. The illuminant can be implemented, in particular, as an LED. The illuminant can be operated, in particular, permanently or continuously in order to be able to monitor the wear state of the coupling eyelet bushing at any time. Furthermore, the corresponding effort of switching the illuminant on and off or of having to provide corresponding electrical options for this, such as an externally accessible switch on the coupling eyelet bushing, can be avoided.

[0030] The materials of the first and second wear elements, for example made of plastic, can be colored accordingly and be translucent, so that the materials of the first and second wear elements can be illuminated radially from the inside or “from behind” and the light emerges outwards in the color of the last illuminated wear element. This can further improve the recognizability and informative value of the previously described aspect of the two-color wear detection means for the person or driver, since the color can be visually perceived more easily due to the glow. This can make it easier or possible for the person or driver to visually recognize the wear detection means itself and in particular its color, particularly in the dark, in poor visibility conditions and / or when the surface of the coupling eye bushing is dirty.

[0031] Providing the coupling eyelet with a hollow space, in particular with an annular hollow space, can create sufficient installation space within the coupling eyelet or the coupling device to accommodate at least one illuminant, and in particular, multiple illuminants. In particular, a correspondingly small hollow space can sufficiently prevent weakening of the coupling eyelet, allowing the coupling eyelet to perform its force-transmitting function without restriction.

[0032] Placing the lamp in the coupling eyelet, i.e., outside the replaceable coupling eyelet socket, can make it possible to use the lamps continuously, i.e., to replace a worn coupling eyelet socket along with the worn wear detection device without having to replace the lamp as well. This can save costs, effort, and / or materials.

[0033] According to a further aspect of the invention, the wear detection means comprises, preferably within a cavity of the coupling eyelet, preferably within an annular cavity of the coupling eyelet, and / or within a horizontal cavity of the coupling eyelet and / or a shaft, at least one electrical energy storage device, which is designed to electrically supply at least the illuminating means, preferably furthermore a detection unit and / or a wireless communication unit. This allows electrical energy to be supplied to the illuminating means and, if appropriate, several or all of the illuminating means directly from the coupling eyelet socket, the coupling eyes, or the coupling device itself, so that an electrically conductive connection to the electrical energy supply from outside the coupling eyelet socket, the coupling eyes, or the coupling device can be dispensed with.This can correspondingly minimize the effort required to use at least one light source, as described above. Particularly when using LEDs as light sources, which typically have very low electrical energy requirements, the electrical energy storage device can ensure continuous operation of the light source for years, eliminating the need to recharge or replace the electrical energy storage device. If necessary, other electrical or electronic components of the wear detection device can also be powered by the electrical energy storage device, eliminating the need for additional or separate electrical energy storage devices.

[0034] According to a further aspect of the invention, the wear detection means is arranged in at least one horizontal cavity of the coupling eye bushing, wherein the wear detection means has at least a first wear element which is arranged between the inner edge of the horizontal cavity of the coupling eye bushing and a wear limit, and at least one second wear element which is arranged within the wear limit, wherein at least one electrically conductive element of an electrical circuit is arranged at the wear limit such that the electrically conductive element is severed by the wear of the coupling eye bushing when the wear reaches the wear limit, wherein the wear detection means is preferably arranged within a cavity of the coupling eye, preferably within an annular cavity of the coupling eye, and / or within a horizontal cavity of the coupling eye and / oror a shaft, has a detection unit configured to monitor the electrical conductivity of the electrically conductive element and, preferably upon severing the electrically conductive element, to output corresponding information. The two wear elements can be the previously described two single-colored first and second wear elements or two wear elements of any desired color.

[0035] This aspect of the invention is based on the finding that, in addition to or as an alternative to the previously described optical wear monitoring options, a sensory monitoring option can also be created. For this purpose, an electrically conductive element, such as an electrical conductor or an electrical conductor loop, can be guided precisely to the wear limit of permissible wear of the coupling eyelet bushing at this point. This can be achieved, in particular, within the second wear element, for example, a plastic part, which can simultaneously be covered or protected from the outside by the first wear element, for example, a plastic part.

[0036] In this case, the first, outer wear element is abraded or worn along with the coupling eye bushing until the wear limit is reached. When the wear limit is reached, the electrically conductive element is also subject to abrasion or wear, which acts externally on the coupling eye bushing. The electrically conductive element is abraded to such an extent that it is severed, meaning that the electrically conductive element can no longer transmit electrical current or electrical voltage can no longer be applied via the electrically conductive element, which can be detected by the detection unit. The detection unit can thus automatically determine that the wear limit has been reached.

[0037] Corresponding information can be output externally by the detection unit. If multiple wear detection devices are used, the information from the detection unit can also contain information identifying the respective worn or severed electrically conductive element or its detection unit, so that the location at which the permissible wear has been reached or exceeded can be identified.

[0038] In any case, the corresponding information can be output by means of a wireless communications unit, which can at least wirelessly transmit data or information to the outside of the coupling eye socket and preferably also receive data and information from outside. This can be done automatically by the detection unit immediately when the wear limit is reached, so that the person or driver can react to this immediately. This information can be output continuously or regularly by the detection unit to ensure that this information reaches the person or driver. The output of this information by the detection unit can, if necessary, be terminated by an acknowledgement of receipt from the person or driver in order to save electrical energy on the part of the detection unit.The output of this information by the detection unit may, if necessary, additionally or alternatively only occur upon a query or in response to an external request, as will be described in more detail below.

[0039] In any case, this information can be output by the detection unit to the person or driver in such a way that this information is transmitted wirelessly to an electronic receiving device, such as a mobile device, for example in the form of a smartphone, a tablet, or the like, of the person or driver. Additionally or alternatively, this information can also be transmitted wirelessly by the detection unit to an electronic receiving device of the towing vehicle, received and further processed there, and output or displayed to the driver via an output element, in particular a display element of the towing vehicle. In this case, this information can, if necessary, be forwarded wirelessly by the towing vehicle or its control unit to a fleet management system in order to be able to consider and plan the replacement of the worn coupling eye bushing.

[0040] According to a further aspect of the invention, the wear detection means comprises, preferably within a cavity of the coupling eyelet, preferably within an annular cavity of the coupling eyelet, and / or within a horizontal cavity of the coupling eyelet and / or a shaft, at least one wireless communication unit, preferably a wireless transmission unit, which is designed to wirelessly transmit at least one piece of information from the detection unit to the outside of the coupling eyelet bushing. This allows the corresponding properties already described above to be implemented.

[0041] According to a further aspect of the invention, the wireless communication unit is configured to be wirelessly requested from outside the coupling eyelet socket to transmit information from the detection unit. This allows the corresponding properties described above to be implemented.

[0042] According to a further aspect of the invention, the wirelessly transmitted information from the detection unit contains the state of the electrically conductive element and / or information derived from the state of the electrically conductive element. The state of the electrically conductive element can be differentiated at least as to whether the electrically conductive element is severed or not. Information derived from this by the detection unit can be that the corresponding wear limit is recognized as having been reached or not yet reached. However, the latter conclusion can also be drawn where the wirelessly transmitted information from the detection unit is received and further processed, which can simplify the implementation of the detection unit and thus save electrical energy, costs, and / or installation space.

[0043] According to a further aspect of the invention, the wear detection means, preferably at least a first wear element and a second wear element, are arranged at least twice in the coupling eye bushing, preferably diametrically opposite each other to the longitudinal axis. This can increase the number of locations within the coupling eye bushing that can be monitored for wear as described above. Arranging the two wear detection means diametrically opposite each other to the longitudinal axis, i.e., offset by 180° from each other in the plane of the cross-section, can make it possible to monitor wear as evenly distributed as possible.

[0044] According to a further aspect of the invention, the wear detection means, preferably at least a first wear element and a second wear element, are arranged in the coupling section at least twice in pairs, preferably as a pair diametrically opposite each other to the longitudinal axis and particularly preferably offset in pairs at right angles to each other. Thus, the total of four wear elements can be arranged in one plane of the cross-section, in particular offset by 90° to each other. This allows the uniformity of monitoring the coupling eyelet bushing for wear to be further increased.

[0045] According to a further aspect of the invention, the detection unit is designed to monitor the electrical conductivity of all electrically conductive elements and, preferably upon severing at least one of the electrically conductive elements, to output corresponding information. This avoids the expense of using multiple detection units, while simultaneously allowing the single detection unit to be configured to monitor all electrically conductive elements. This can simultaneously reduce electrical energy consumption and / or the required installation space.

[0046] According to a further aspect of the invention, the wirelessly transmitted information from the detection unit further contains an identification of the severed electrically conductive element. This can enable the differentiation of the individual electrically conductive elements even when using a single detection unit.

[0047] The invention also relates to a coupling eye bushing for use in a coupling eye of a coupling device as described above. This makes it possible to provide a coupling eye bushing for implementing and using a coupling device with the aspects described above.

[0048] The invention also relates to a rear vehicle with a coupling device as described above. This allows the above-described aspects of a coupling device according to the invention to be implemented and used in a rear vehicle.

[0049] The invention further relates to a vehicle combination having a rear vehicle as described above. This allows a vehicle combination to be created in order to implement and utilize the above-described aspects of a coupling device according to the invention in the rear vehicle thereof.

[0050] Several embodiments and further advantages of the invention are illustrated schematically below and explained in more detail in conjunction with the following figures. Fig. 1 a schematic side view of a vehicle combination according to the invention with a second coupling device according to the invention according to a first embodiment; Fig. 2 a detailed view of the Fig. 1, partly in section; Fig. 3 a schematic side view, partly in section, of the second coupling device according to the invention according to the first embodiment; Fig. 4 a schematic side view, partly in section, of a second coupling device according to the invention according to a second embodiment; Fig. 5 is a schematic side view, partly in section, of a second coupling device according to the invention according to a third embodiment; and Fig. 6 a cross section through the transition section of the second coupling device according to the second embodiment of the Fig. 4.

[0051] The above figures are viewed in Cartesian or cylindrical coordinates. In Cartesian coordinates, there extends a longitudinal direction X, which can also be referred to as depth X or length X. Perpendicular to the longitudinal direction X extends a transverse direction Y, which can also be referred to as width Y. Perpendicular to both the longitudinal direction X and the transverse direction Y extends a vertical direction Z, which can also be referred to as height Z. The longitudinal direction X and the transverse direction Y together form the horizontal X, Y, which can also be referred to as the horizontal plane X, Y. In the vertical direction Z, a longitudinal axis X' extends, also in cylindrical coordinates. Perpendicular to the longitudinal axis X', a radial direction R extends away from the longitudinal axis X'. Perpendicular to the radial direction R and around the longitudinal axis X' extends a circumferential direction U.

[0052] Fig. 1 shows a schematic side view of a vehicle combination 3, 4 according to the invention with a trailer coupling 1, 2 with a second coupling device 2 according to the invention according to a first exemplary embodiment. In a direction of travel A, which can also be referred to as the direction of movement A or the direction of towing A, the vehicle combination 3, 4 has a front vehicle 3 in the direction of towing A, which can also be referred to as the towing vehicle 3, and a rear vehicle 4 in the direction of towing A, which can also be referred to as the trailer 4. The vehicle combination 3, 4 can perform a travel movement in the direction of travel A on a surface 5.

[0053] A first coupling device 1 is fixedly arranged on the rear of the towing vehicle 3 in the longitudinal direction X, which first coupling device 1 points towards the trailer 4 in the longitudinal direction X. Furthermore, a second coupling device 2 according to the invention is fixedly arranged on the front of the trailer 4, facing the towing vehicle 3, in the longitudinal direction X, on a frame 40 or on a frame 40 of the trailer 4. The two coupling devices 1, 2 connect the towing vehicle 3 to the trailer 4 in a force-transmitting manner in the longitudinal direction X and thus together form the trailer coupling 1, 2, which can also be referred to as a trailer coupling system 1, 2.

[0054] Fig. 2 shows a detailed view of the Fig. 1, partially in section. The trailer coupling 1, 2 according to the first embodiment of the Fig. 1 to 3 is designed as a bolt coupling or as a bolt coupling system. Accordingly, the first coupling device 1 of the towing vehicle 3 has a coupling receptacle 10 with a coupling mouth 11, which receives a coupling eye 21 of a shaft 20 of the second coupling device 2 in the longitudinal direction X. The coupling eye 21 of the second coupling device 2 can also be referred to as a towing eye 21. The coupling eye 21 is annularly formed at the end of the shaft 20 in one piece, i.e. integrally, which ends facing away from the trailer 4. The coupling eye 21 has a recess (not designated) in the center, which is filled by a coupling eye bushing 22 according to the invention. The coupling eye bushing 22 can also be referred to as a towing eye bushing 22.

[0055] The coupling eye bushing 22 forms a coupling eye 23 in the center, running in the vertical direction Z, into which a coupling pin 12 of the first coupling device 1 is inserted from above in the vertical direction Z in order to create a positive connection between the two coupling devices 1, 2. The coupling eye 23 can also be referred to as a coupling eye eye 23, as a towing eye eye 23 or as a towing eye bushing 23. The shaft 20 can also be referred to as a trailer shaft 20 or as a towing shaft 20. The shaft 20 can also be referred to as a drawbar 20 or as a trailer drawbar 20. The coupling pin 12 or its body is made of metal in one piece, i.e. integral, and is rotationally symmetrical to the longitudinal axis X'.

[0056] Fig. 3 shows a schematic side view, partly in section, of the second coupling device 2 according to the invention in accordance with the first exemplary embodiment. The coupling eye bushing 22 is made of metal, is ring-shaped and rotationally symmetrical to the longitudinal axis X' and forms the radially inner surface, closed in the circumferential direction U, of the coupling eye 21 of the second coupling device 2. When the trailer 4 is coupled to the towing vehicle 3, the coupling eye bushing 22 receives the coupling pin 12 thereof and completely encloses the coupling pin 12 in the circumferential direction U. As a result, during operation of the vehicle combination 3, 4 with trailer 4 and towing vehicle 3, abrasion or wear of the cylindrical inner surface of the coupling eye bushing 22 can occur, which over time can change the cross-section orthe material thickness of the coupling eye bushing 22 of the second coupling device 2 can be weakened to such an extent that a secure transmission of power between the trailer 4 and the towing vehicle 3 via the coupling eye bushing 22 or via the coupling eye 21 can no longer be guaranteed.

[0057] According to the invention, the wear of the coupling eyelet bushing 22 according to the first embodiment of the Fig. 1 to 3 can be controlled or monitored by a person, such as the driver of the vehicle combination 3, 4, more easily, quickly and / or more frequently than previously known in that a continuous horizontal cavity 26 is present in the coupling eye bushing 22, diametrically opposite one another in the longitudinal direction X on each side, which cavity 26 extends from the inside of the cylindrical inner surface of the coupling eye bushing 22 radially away from the longitudinal axis X' to the opposite outer surface of the coupling eye bushing 22.A wear detection means 6 is introduced into each of the two horizontal cavities 26, which is held there in a materially bonded manner, for example by an adhesive between the inner surface of the horizontal cavity 26 and the outer surface of the wear detection means 6, or in a force-locked manner, for example by an at least slight oversize of the outer contour of the wear detection means 6 relative to the horizontal cavity 26.

[0058] Both wear detection means 6 have a first, inner colored wear element 60 directed radially inward at the edge, which is followed by a second, outer colored wear element 61 directed radially outward. The two first, inner colored wear elements 60 are connected to the respective second, outer colored wear element 61 by a material fit, for example by gluing or by a one-piece, i.e., integral, manufacture. The terms "inside" and "outside" with regard to the colored wear elements 60, 61 are to be understood radially in cylindrical coordinates.

[0059] The two first, inner colored wear elements 60 have a different color than the second, outer colored wear elements 61. Preferably, the two first, inner colored wear elements 60 are green, in particular neon green, and the second, outer colored wear elements 61 are red, in particular neon red. The transition or boundary between a first, inner colored wear element 60 and the corresponding second, outer colored wear element 61 is provided by the dimensioning of the wear elements 60, 61 such that this transition corresponds to the permissible wear limit of the coupling section 13 of the coupling eyelet bushing 22.

[0060] If the trailer 4 is without a towing vehicle 3, i.e. there is no coupling pin 12 engaged with the second coupling device 2 or with its coupling eye bushing 22, the coupling eye bushing 22 according to the invention is accessible obliquely to the horizontal plane X, Y and can be visually inspected in particular by the person, such as the driver, who wishes to connect the towing vehicle 3 to his trailer 4. In this case, the person can visually recognize the wear detection means 6 of the coupling eye bushing 22 from at least one side or laterally from two sides and determine whether (in each case) the first, inner colored wear element 60 or the second, outer wear element 61 is visible from the outside.

[0061] If the person recognizes the first, inner colored wear element 60, it can be concluded that at this point on the coupling eye bushing 22 of the second coupling device 2, the wear of the material of the coupling eye bushing 22, which correspondingly also reduces the radial extent of the respective wear detection means 6, is still within a permissible level. If the person recognizes the second, outer colored wear element 61, it can be concluded that at this point on the coupling eye bushing 22 of the second coupling device 2, the first, inner colored wear element 60 has been completely worn away and therefore the second, outer colored wear element 61 radially underneath is visible from the outside. This means that at this point on the coupling eye bushing 22 of the second coupling device 2, the permissible wear has already been reached oris exceeded and the trailer 4 can no longer be used safely on the towing vehicle 3. Instead, the coupling eye bushing 22 of the second coupling device 2 must be replaced.

[0062] Fig. Figure 4 shows a schematic side view, partially in section, of a second coupling device 2 according to the invention according to a second embodiment. In this case, a cavity 24 of the coupling eye 21 is further provided in the form of an annular cavity 24 circular around the longitudinal axis X', into which the previously described horizontal cavities 26 of the coupling eye bushing 22 each open radially, see, for example, Fig. 6. The annular cavity 24 of the coupling eye 21 is thus designed as a groove-like depression open radially to the longitudinal axis X' and is closed off to form a channel by the pressed-in coupling eye bushing 22. On the axis of the longitudinal direction X, which runs centrally along the shaft 20 of the second coupling device 2, the annular cavity 24 of the coupling eye 21 merges into a horizontal cavity 25, which extends through the coupling eye 21 into the shaft 20 and completely through the latter. Accordingly, the horizontal cavity 25 can be introduced into the second coupling device 2 from the outside, i.e. facing away from the coupling eye 21, along the axis of the longitudinal direction X by means of a bore and can therefore also be referred to as a core bore 25.

[0063] Just as in the first embodiment of the Fig. 1 to 3 are also in the second embodiment of the Fig. 4 and Fig. 6, several horizontal cavities 26 are present through the coupling eye bushing 22, each of which is filled with a wear detection agent 6, as previously described. The second coupling device 2 according to the second embodiment of the Fig. 4 and Fig. 6, however, has four instead of two wear detection means 6, which are arranged offset by 90° to each other in the longitudinal direction X and in the transverse direction Y, see Fig. 6. For each wear detection means 6, the first, inner colored wear element 60 is arranged as described above, followed by the second, outer colored wear element 61 as described above, which extends radially outward to the respective end of the horizontal cavity 26 of the coupling eyelet bushing 22. The wear elements 60, 61 are designed in different colors as described above, with the respective material also being translucent.

[0064] At the radially outer ends of the second, outer colored wear elements 61, a light source 62 in the form of an LED 62 is arranged radially inwardly such that the wear elements 60, 61 are illuminated radially inward by the light of the respective LED 62 when the LED 62 is operated. The LEDs 62 can be supplied with electrical energy for continuous or permanent operation by an electrical energy storage device 66 in the form of a battery 66, which is arranged within the horizontal cavity 25 of the coupling eye 21 or the shaft 20. The operation of the LEDs 62 can be started when the second coupling device 2 is mounted on the trailer 4 and can continue until the electrical energy of the battery 66 is used up.

[0065] Also in this case of the second embodiment of the Fig. 4 and Fig. 6, the corresponding locations of the coupling eyelet bushing 22 of the second coupling device 2 can be determined by a person as previously with regard to the first embodiment of the Fig. 1 to 3. In doing so, the person can visually perceive a light in the color of the first, inner colored wear element 60, as long as, as described above, the wear limit is maintained. If the wear limit is reached or exceeded at a point on the coupling eye bushing 22 of the second coupling device 2, the first, inner colored wear element 60 is abraded at this point, and the light of the corresponding LED 62 emerges outward, i.e., radially inward, in the color of the second, outer colored wear element 61.

[0066] Accordingly, the person can distinguish between permissible and impermissible wear based on the color of the light, which can be visually perceived at the respective location. This allows the inventive wear control of the coupling eyelet bushing 22 of the second coupling device 2 according to the first embodiment of the Fig. 1 to 3 can be improved for the person in such a way that the colored wear detection means 6 can be perceived better and more reliably than without this backlighting, particularly in the dark or in poor visibility conditions, for example in rain or fog, or when the inner surface of the coupling eye bushing 22 of the second coupling device 2 is dirty. In particular, in the dark or in poor visibility conditions, the person can forgo illuminating the coupling eye bushing 22 of the second coupling device 2, for example with a flashlight, in order to be able to visually recognize the wear detection means 6. Likewise, the effort of having to clean or wiping a dirty surface of the coupling eye bushing 22 of the second coupling device 2 in order to be able to visually recognize the wear detection means 6 can be eliminated.

[0067] Fig. Figure 5 shows a schematic side view, partly in section, of a second coupling device 2 according to the invention according to a third embodiment. In this case, the coupling eyelet bushing 22 is, as in the second embodiment, the Fig. 4 and Fig. 6, which also applies to the extension of the wear elements 60, 61, which are colored as in the first embodiment of the Fig. 1 to 3 or can also be formed with the same, indeterminate color.

[0068] In each case, an electrically conductive element 63 in the form of a conductor loop 63 extends through the respective second, outer wear element 61 such that the conductor loops 63 run or reverse at the boundary between the first, inner wear element 60 and the second, outer wear element 61. All conductor loops 63 are electrically conductively connected to a detection unit 64, which is arranged within the horizontal cavity 25 of the coupling eye 21 or the shaft 20 and can also be referred to as a control unit 64. The detection unit 64 is connected for signal transmission to a wireless communication unit 65, which is also arranged within the horizontal cavity 25 of the coupling eye 21 or the shaft 20 and can at least transmit wireless signals, which is why the wireless communication unit 65 can also be referred to as a transmission unit 65.Both the detection unit 64 and the transmission unit 65 are electrically connected to the battery 66 and are powered by electrical energy from the battery 66.

[0069] If, in this case, the wear of the coupling eyelet bushing 22 reaches the wear limit at one point, the corresponding conductor loop 63 is abraded and severed. The detection unit 64 can determine for each of the conductor loops 63 whether the conductor loop 63 is continuously electrically conductive or severed. This can be done, for example, by applying a measuring voltage to the detection unit 64. The detection unit 64 can thereby distinguish whether or not the wear at those points on the coupling eyelet bushing 22 of the second coupling device 2 at which the conductor loops 63 are provided is still within an acceptable level. Corresponding information can be wirelessly transmitted from the detection unit 64 to the outside of the second coupling device 2 by means of the transmission unit 65.

[0070] This information can be received, for example, by a handheld device such as a mobile terminal such as a smartphone of a person or the driver of the vehicle group 3, 4 and displayed there. This information can be transmitted continuously, although this can increase electrical energy consumption. This information can also only be transmitted when the person or driver requests the second coupling device 2 according to the invention to do so by sending corresponding information, which can also be done by the smartphone. This allows the corresponding information to be retrieved as needed, which can reduce the electrical energy consumption of the second coupling device 2 according to the invention and thus increase the operating time of the detection unit 64 and the transmission unit 65.

[0071] This information can, for example, also be received by a control unit of the towing vehicle 3 and displayed there to the driver. In this case, too, the information can be transmitted by the second coupling device 2 according to the invention continuously or only upon request by the control unit of the towing vehicle 3. In any case, the received information can be displayed to the driver of the towing vehicle 3 in order to be informed about the roadworthy condition of the coupling eye bushing 22 of the second coupling device 2, particularly during operation of the vehicle combination 3, 4.

[0072] In any case, the detection unit 64 can distinguish between the various conductor loops 63, so that the information transmitted outward can also include an identification of the respective conductor loops 63. Thus, if one of the first, internal wear elements 60 reaches its limit and the corresponding conductor loop 63 is severed, the person or driver can be specifically informed at which point on the coupling eyelet bushing 22 of the second coupling device 2 the permissible wear is reached or exceeded. LIST OF REFERENCE SYMBOLS (part of the description) A direction of travel; direction of movement; direction of train X longitudinal direction; depth; length YX, transverse direction; width Z vertical direction; height Y Horizontal; horizontal plane R radial direction U circumferential direction X' longitudinal axis 1, 2 trailer coupling; trailer coupling system; coupling devices 1 first coupling device of the front vehicle in the direction of travel A 3 10 Coupling receptacle 11 Coupling mouth 12 coupling bolts 13 Coupling section 2 second coupling device of the rear vehicle in the direction of travel A 4 20 (Trailer) drawbar; (Trailer / towing) shaft 21 Coupling eye; towing eye 22 coupling eye bushing; drawbar eye bushing 23 coupling eye; coupling eye; drawbar eye 24 Cavity or ring cavity of the coupling eyelet 21 25 Horizontal cavity of the coupling eyelet 21 and / or the shaft 20; core bore 26 Horizontal cavity of the coupling eye bushing 22 3, 4 Vehicle combination 3 in the direction of towing A front vehicle; towing vehicle 4 rear vehicle in direction of travel A; trailer 40 frame; frame 5 Underground 6 Wear detection agents 60 first, inner (colored) wear elements 61 second, outer (colored) wear elements 62 light sources; LEDs 63 electrically conductive elements; conductor loops 64 Detection unit; control unit 65 wireless communication unit or wireless transmitter unit 66 electrical energy storage; battery

Claims

[1] Coupling device (2) for a rear vehicle (4) of a vehicle combination (3, 4) in the direction of pull (A), with a coupling eyelet (21) with a coupling eyelet bushing (22), the coupling eyelet (23) of which extends along a longitudinal axis (X'), characterized by at least one wear detection means (6), preferably arranged centrally along the longitudinal axis (X'), which is arranged at least in the coupling eyelet bushing (22) in a manner oriented perpendicular to the longitudinal axis (X') such that wear of the coupling eyelet bushing (22) perpendicular to the longitudinal axis (X') can be detected optically and / or by sensors. [2] Coupling device (2) according to claim 1, characterized by , that the wear detection means (6) is arranged in at least one horizontal cavity (26) of the coupling eyelet bush (22), wherein the wear detection means (6) at least one first wear element (60) of a first color, which is arranged between the inner edge of the horizontal cavity (26) of the coupling eye bushing (22) and a wear limit, and at least one second wear element (61) of a second, different color, which is arranged within the wear limit. [3] Coupling device (2) according to claim 2, characterized by in that the wear detection means (6) has at least one illuminating means (62) which is arranged within the horizontal cavity (26) of the coupling eye bushing (22) and / or within a cavity (24) of the coupling eye (21), preferably within an annular cavity (24) of the coupling eye (21), and is designed to illuminate the first wear element (60) through the second wear element (61). [4] Coupling device (2) according to claim 3, characterized bythat the wear detection means (6), preferably within a cavity (24) of the coupling eyelet (21), preferably within an annular cavity (24) of the coupling eyelet (21), and / or within a horizontal cavity (25) of the coupling eyelet (21) and / or a shaft (20), has at least one electrical energy store (66) which is designed to electrically supply at least the lighting means (62), preferably furthermore a detection unit (64) and / or a wireless communication unit (65). [5] Coupling device (2) according to one of the preceding claims, characterized by , that the wear detection means (6) is arranged in at least one horizontal cavity (26) of the coupling eyelet bush (22), wherein the wear detection means (6) at least one first wear element (60) arranged between the inner edge of the horizontal cavity (26) of the coupling eye bushing (22) and a wear limit, and at least one second wear element (61) which is arranged within the wear limit, wherein at least one electrically conductive element (63) of an electrical circuit is arranged at the wear limit such that the electrically conductive element (63) is severed by the wear of the coupling eyelet bushing (22) when the wear reaches the wear limit, wherein the wear detection means (6), preferably within a cavity (24) of the coupling eyelet (21), preferably within an annular cavity (24) of the coupling eyelet (21), and / or within a horizontal cavity (25) of the coupling eyelet (21) and / or a shaft (20), has a detection unit (64) which is designed to monitor the electrical conductivity of the electrically conductive element (63) and, preferably when the electrically conductive element (63) is severed, to output corresponding information. [6] Coupling device (2) according to claim 5, characterized bythat the wear detection means (6), preferably within a cavity (24) of the coupling eyelet (21), preferably within an annular cavity (24) of the coupling eyelet (21), and / or within a horizontal cavity (25) of the coupling eyelet (21) and / or a shaft (20), has at least one wireless communication unit (65), preferably a wireless transmission unit (65), which is designed to transmit at least one item of information from the detection unit (64) wirelessly to the outside of the coupling eyelet (21). [7] Coupling device (2) according to claim 6, characterized by that the wireless communication unit (65) is designed to be requested wirelessly from outside the coupling eyelet (21) to transmit information of the detection unit (64). [8] Coupling device (2) according to claim 6 or 7, characterized bythat the wirelessly transmitted information of the detection unit (64) contains the state of the electrically conductive element (63) and / or information derived from the state of the electrically conductive element (63). [9] Coupling device (2) according to one of the preceding claims, characterized by that the wear detection means (6), preferably at least a first wear element (60) and a second wear element (61), is arranged at least twice, preferably diametrically opposite one another to the longitudinal axis (X'), in the coupling eyelet bushing (22). [10] Coupling device (2) according to one of the preceding claims, characterized bythat the wear detection means (6), preferably at least a first wear element (60) and a second wear element (61), is arranged in the coupling eyelet bushing (22) at least twice in pairs, preferably as a pair diametrically opposite one another to the longitudinal axis (X') and particularly preferably offset in pairs at right angles to one another. [11] Coupling device (2) according to one of claims 5 to 8 and according to one of claims 9 or 10, characterized by that the detection unit (64) is designed to monitor the electrical conductivity of all electrically conductive elements (63) and, preferably when at least one of the electrically conductive elements (63) is severed, to output corresponding information. [12] Coupling device (2) according to claim 11, characterized bythat the wirelessly transmitted information of the detection unit (64) further contains an identification of the severed electrically conductive element (63). [13] Coupling eyelet bushing (22) for use in a coupling eyelet (21) of a coupling device (2) according to one of the preceding claims. [14] Rear vehicle (4) with a coupling device (2) according to one of claims 1 to 12. [15] Vehicle combination (3, 4) with a rear vehicle (4) according to claim 14.

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