Kingpin for a fifth-wheel coupling, fifth-wheel coupling with kingpin, and utility vehicle therewith

Abstract

The invention relates to a kingpin (10) for a fifth-wheel coupling of a utility vehicle, with a journal shaft (3) which extends along a centre axis (M) and has a journal head (2) at its lower end, wherein the journal shaft (3) has a fastening flange (4) at its upper end remote from the journal head (2), and with a receiving flange (5) which is placed onto the upper end of the journal shaft (3) and is fixed to the fastening flange (4). According to the invention, a measuring device for detecting driving-dynamic reaction forces is provided, wherein the measuring device is arranged in a cavity (15) which is formed in the fixed state between the receiving flange (5) and the upper end of the journal shaft (3).

Description

[0001] Kingpin for a fifth wheel, fifth wheel with kingpin and commercial vehicle hereby

[0002] The invention relates to a kingpin for a fifth wheel coupling of a commercial vehicle according to the preamble of claim 1, a fifth wheel coupling with such a kingpin according to claim 14 and a commercial vehicle with this according to claim 15.

[0003] Fifth wheel couplings are used to couple a semi-trailer (hereinafter referred to as a trailer) to a tractor unit. Typically, a fifth wheel plate with a fifth wheel coupling is mounted on the tractor unit side, into which a kingpin (also known as a king pin or kingpin) mounted on the trailer side can be coupled and secured. All dynamic driving loads are then transferred from the tractor unit to the trailer and vice versa via the kingpin and the fifth wheel coupling.

[0004] Kingpins for fifth wheel couplings typically have a journal shaft with a journal head. At the opposite end, the journal shaft usually has a mounting flange, which is used to mechanically secure it to a trailer body or chassis via fastening screws. For mechanical reinforcement and connection, a mounting flange is usually provided between the trailer chassis and the kingpin, through which the kingpin is connected to the trailer chassis.

[0005] The current state of the art proposes various measurement variants for determining mechanical reaction forces on the fifth wheel coupling. Measuring driving dynamic reaction forces can be of great importance, for example, in the context of a trailer's auxiliary drive axle. This allows data to be obtained independently of the tractor's drive signals, enabling the trailer's auxiliary drive axle to be operated in a supporting manner.

[0006] For example, the current state of the art proposes measuring reaction forces acting on the fifth wheel coupling directly via the trailer-side kingpin or the PTO shaft in order to determine the driving behavior of the tractor unit. Alternatively, solutions are proposed that incorporate strain gauges positioned directly in the fastening bolts. Knowing whether the tractor unit is currently braking, pulling, or changing direction on the trailer, the auxiliary drive axle can be operated in a driving or braking mode. Sensors proposed in the current state of the art include strain gauges, load cells, load washers, and piezo sensors.

[0007] In the version with measuring washers, these are installed in the bolted connection between the kingpin and the trailer and thus measure the clamping forces of the bolts. By arranging the bolts circumferentially around the kingpin or the mounting flange, the tensile and compressive forces in the measuring washers can be used to determine the forces acting on the kingpin.

[0008] However, the installation and maintenance of these sensors in the current state of the art are complex. Furthermore, the kingpin's journal shaft is exposed to strong dynamic loads during its intended use, significantly reducing the durability of measuring devices located directly on the journal shaft or in the surrounding area. Mounting the measuring device directly on the journal is also impractical due to space constraints. Furthermore, strain gauges used to measure reaction forces on the kingpin, for example, have proven to be too temperature-sensitive and exhibit excessive variance in their measurement ranges. Furthermore, positioning strain gauges within the mounting screws does not permit the implementation of a differential measurement method.

[0009] The object of the present invention is therefore to overcome the disadvantages of the prior art and to provide a solution with which a measurement on the kingpin or fifth wheel coupling can be carried out in a simple, cost-effective and easy-to-install manner, particularly during maintenance. Furthermore, the solution should allow for interference-resistant measurements. The kingpin or fifth wheel shaft should be replaceable without great effort and without impairing the (force) measurement device. The solution should be particularly suitable for use in commercial vehicles and for semi-trailer trucks with trailer-side auxiliary drives, as well as generally applicable to trailer couplings between two vehicles.

[0010] Main features of the invention are set forth in the characterizing part of claim 1 and claims 14 and 15. Embodiments are the subject of claims 2 to 13.

[0011] In a kingpin for a fifth wheel coupling of a commercial vehicle, with a pivot shaft which extends along a central axis and has a pivot head at its lower end, wherein the pivot shaft has a fastening flange at its upper end facing away from the pivot head, and with a receiving flange which is placed on the upper end of the pivot shaft and is fixed to the fastening flange, a measuring device for detecting driving dynamic reaction forces is provided according to the invention, wherein the measuring device is arranged in a cavity which, in the fixed state, is formed between the receiving flange and the upper end of the pivot shaft.

[0012] Due to the inventive spatial and, above all, mechanical separation of the measuring device from the journal shaft, the latter is significantly less exposed to dynamic driving forces. Because the measuring device is located in a cavity between the mounting flange and the upper end of the journal shaft, it is effectively protected from environmental influences and strong mechanical stress. Furthermore, the measuring device does not need to be replaced or rewired when replacing a worn kingpin. Calibrating the measuring device to match the new kingpin is sufficient.

[0013] The measuring device according to the invention is preferably primarily designed to determine driving dynamic reaction forces acting radially to the center axis of the PTO shaft, which result from the driving behavior of the tractor unit in the area of ​​the kingpin or in the area of ​​the fifth wheel coupling. When these radial forces act, the distances between the mounting flange and the upper end of the PTO shaft change due to mechanical deformations. The measuring device is preferably designed to measure these changes in distance and to determine the radial reaction forces based on the measured data.

[0014] By providing the measuring device according to the invention in the cavity between the receiving flange and the upper end of the journal shaft, changes in distance between the receiving flange and the upper end of the journal shaft, which are directly related to the radial forces acting on it, can advantageously be recorded. As a result, the measuring device and the preferably associated electronic connection and cabling are simultaneously protected as far as possible from external environmental influences. High levels of humidity and temperature can prevail, particularly in the lower area of ​​the trailer or chassis, which is why the sensitive measuring device would otherwise be exposed to strong influences. The cavity is preferably disc-shaped or essentially cylindrical, with the cavity in particular being plate-shaped. This measure additionally supports precise distance measurement because the discs orThe plate shape, by its very nature, does not have an excessive axial extension along the center axis of the kingpin. Otherwise, the distance between the mounting flange and the upper end of the journal shaft might be too large for the measurement in question. It is important in this context that even small deformations or changes in distance can be detected by the measuring device.

[0015] The mounting flange is attached to the upper end of the journal shaft as a separate component. The upper end of the journal shaft is preferably flanged to the mounting flange via the fastening flange. The fastening flange of the journal shaft can preferably be releasably fixed to the mounting flange via fixing means. The fixing means are preferably designed as screws, wherein the screws are in particular threaded screws which, in the case of a 2-inch kingpin, fix the journal shaft to the mounting flange in accordance with Directive ECE R55-01 and comply with the standards DIN 74080 and ISO 337, wherein the threaded screws, in the case of a 3.5-inch kingpin, fix the journal shaft to the mounting flange in accordance with Directive ECE R55-01 and comply with the standards DIN 74083 and ISO 4086.Preferably, the receiving flange lies fully in circumferential direction against the fastening flange at the level of the fixing means and is fixed in such a way that the cavity is surrounded by the flanged surface.

[0016] The receiving flange primarily functions as an additional fastening or strengthening element between the trailer and the PTO shaft. Preferably, the receiving flange can simultaneously serve as a receiving element for the measuring device. In this context, a preferred embodiment of the invention provides that the receiving flange has a plate base, wherein the plate base has an underside facing the cavity for receiving the measuring device. The plate base can preferably be arranged parallel to the upper end of the PTO shaft. Furthermore, the receiving flange can preferably be substantially plate-shaped, wherein the plate base of the receiving flange can in particular be disc-shaped. Furthermore, it is preferred that the underside of the plate base is flat.These designs create a flat and uniform support surface for the measuring device on the underside of the plate base, allowing it to rest and be attached to the underside of the chassis, for example. The disc-shaped design of the plate base also supports the formation of the cavity for accommodating the measuring device.

[0017] It is further preferred that the plate base has an upper side facing away from the cavity for fixing the receiving flange. The upper side of the plate base can preferably be integrally connected to a chassis of the trailer. The upper side and underside of the plate base can preferably each be flat. Further preferably, the upper side of the plate base is arranged parallel to an underside of the chassis. The underside of the chassis is preferably arranged parallel to a roadway. In order to be able to fix the upper side securely to the underside of the chassis, the underside of the chassis can preferably be flat. This creates a flat and uniform support surface on the underside of the chassis for the upper side of the plate base, so that the plate base can rest fully on the underside of the chassis and, for example, be integrally connected.According to a further preferred embodiment of the invention, the upper end of the journal shaft has an inner end face facing the cavity, while the upper end of the journal shaft has an outer end face facing the cavity. Preferably, both end faces can be flat, and the end faces can be arranged parallel to the underside of the receiving flange. This measure can, among other things, support the measurement of the radial reaction forces.

[0018] The upper end of the journal shaft preferably has an annular elevation that extends towards the plate base, wherein the annular elevation is arranged between the inner end face and the outer end face. The annular elevation shortens the distance between the underside of the plate base and the upper end of the journal shaft. This could, for example, increase the sensitivity of the measuring device in order to detect even small changes in distance. The annular elevation advantageously offers an annular surface that could, for example, be used in the context of measurement as a corresponding counter surface to the measuring device. It is preferred that the annular elevation is flat on its end face facing the underside of the plate base. This measure leads to an additional improvement in the measuring accuracy of the measuring device when the annular elevation is used as a corresponding measuring counter surface.The measurement would be effectively disrupted by any unevenness on the front side of the ring-shaped elevation. In this case, these interference factors would have to be taken into account when evaluating the measured data. A flat surface according to the described design, on the other hand, supports and significantly improves the measurement process. The ring shape is particularly advantageous because appropriate measuring sensors can be positioned along the preferably closed ring surface.

[0019] According to a further design variant, the measuring device is disc-shaped, with the measuring device having a cross shape. This allows the measuring device to rest over its entire surface at a suitable location and be securely fastened. The disc shape and orientation of the measuring device not only supports the measurement of radially acting forces described above, but also makes the measuring device more compact. This in turn has a beneficial effect on installation space requirements. The measuring device therefore fits into the cavity, which is kept small by design, between the underside of the plate base and the upper end of the journal shaft. Furthermore, the disc-shaped design additionally supports differential measurement. The cross shape of the measuring device can be used, for example, to specify the corresponding directions of the radially acting reaction forces to be determined.Furthermore, this special arrangement can advantageously result in a further improvement in measurement accuracy. It is further preferred that the measuring device be designed symmetrically. This simplifies manufacturing effort and simultaneously reduces production costs.

[0020] The measuring device is preferably arranged centered on the central axis of the PTO shaft, wherein the measuring device is designed to measure changes in distance with respect to the upper end of the PTO shaft. The measuring device preferably comprises at least two distance sensors, more preferably at least four distance sensors, for measuring changes in distance between the plate base and the upper end of the PTO shaft. It is preferred that the individual distance sensors of the measuring device extend radially to the central axis. Contactless distance sensors are preferably provided. This prevents physical wear during measurement. Contactless distance sensors are particularly suitable for fast measurements. Furthermore, capacitive distance sensors, for example, are advantageously insensitive to magnetic fields and can therefore be used without any problems on electrified trailers.

[0021] According to a further preferred embodiment of the invention, the measuring device is arranged directly on the underside of the plate base, wherein the measuring device is positioned opposite the inner end face and the annular elevation. It is further preferred that the measuring device, the underside of the plate base, the inner end face and the annular elevation are each arranged centered on the central axis. Opposite therefore means a coaxial or concentric arrangement of the measuring device, wherein the measuring device is arranged axially spaced from the inner end face and the annular elevation relative to the central axis. The direct arrangement and fixing of the measuring device on the underside of the plate base additionally supports the mechanical decoupling of the measuring device from the journal shaft.At the same time, the measuring device is decoupled from vibrations that can occur, for example, at the upper end of the PTO shaft. Preferably, all cabling and signal routing of the measuring device is also separated from the PTO shaft. All cabling and signal routing is preferably routed toward the underside of the trailer or toward the chassis. This facilitates the connection of the measuring device and additionally protects the cabling and electronics from external influences and stress.

[0022] Further preferably, the measuring device is arranged plane-parallel to the underside of the plate base and plane-parallel to the inner end face and the annular elevation. This allows the measuring device to rest and be secured over its entire surface against the underside of the plate base. In addition, this creates a sufficient distance to the upper end of the journal shaft so that a distance measurement can preferably be carried out between the measuring device on the underside of the plate base and the annular elevation. The plane-parallelism between the measuring device, the underside of the plate-shaped receiving flange and the upper end of the journal shaft significantly improves the measuring accuracy. At the same time, it supports the implementation of a differential measurement. The plane-parallel arrangement also ensures that the reaction forces acting radially to the central axis, as described above, are primarily determined.

[0023] Preferably, the measuring device is designed in particular to measure changes in distance with respect to the annular elevation. It is particularly preferred that the distance sensors of the measuring device are arranged opposite the annular elevation, wherein the distance sensors are arranged parallel to the annular elevation. It is preferred that the radial extent of the individual distance sensors corresponds to a radial extent of the annular elevation. This ensures that the sensor surfaces of the measuring device correspond to the mating surface of the annular elevation. Preferably, the measuring device has signal processing electronics, wherein the signal processing electronics of the measuring device are arranged centered to the central axis of the journal shaft, and wherein the signal processing electronics are surrounded by the individual distance sensors radially to the central axis.This is advantageous for space-saving reasons and provides additional protection for the electronics. Signal and cable routing and connection of the electronics are also greatly simplified. In addition to data transmission and processing, the signal processing electronics can also be used to digitize measured variables and coordinate the corresponding signal transmission. The signals can be fed into a corresponding CAN network for further processing or evaluation and form corresponding parameters for control and regulation circuits. Preferably, at least one distance sensor is aligned radially to the center axis and in the longitudinal direction of the vehicle, with at least one further distance sensor being aligned radially to the center axis and in the transverse direction of the vehicle.Further preferably, at least two distance sensors are aligned radially to the center axis and in the longitudinal direction of the vehicle, with at least two further distance sensors aligned radially to the center axis and in the transverse direction of the vehicle. It is particularly preferred that the distance sensors aligned in the longitudinal direction of the vehicle run radially to the center axis and in the opposite direction in the longitudinal direction of the vehicle, whereas the distance sensors aligned in the transverse direction of the vehicle run radially to the center axis and in the opposite direction in the transverse direction of the vehicle. This special arrangement of the measuring device and the distance sensors has proven to be particularly advantageous because it primarily allows the desired radial forces to be determined. In this case, the measuring device is preferably used to determine radial forces that act in the longitudinal direction of the vehicle (longitudinal force components) and in the transverse direction of the vehicle (lateral force components).In the context of the invention, "longitudinal" primarily refers to all longitudinally and transversely dynamically acting reaction forces. These reaction forces act radially with respect to the center axis of the power take-off shaft and result in the area of ​​the fifth wheel coupling or in the area of ​​the kingpin due to the relative accelerations and / or decelerations and / or changes in direction between the tractor and the trailer. Especially for controlling a trailer's auxiliary drive, it can bring significant advantages if only longitudinally and transversely dynamic radial forces are measured and axial or vertical force components, as well as all other force components, are largely eliminated during the measurement, or can be subsequently masked out or offset for the control and regulation of the auxiliary drive.

[0024] Furthermore, the special arrangement of the distance sensors ensures the implementation of a differential measurement method. This allows, for example, two opposing distance sensors as described above to be differentially evaluated during the measurement. This compensates, in particular, for mechanical common-mode interference or temperature-related deviations that arise when measuring the distance changes. The value to be transmitted for further evaluation and processing (output signal) can correspond to the difference between these two potentials. The major advantage of differential measurement is its significantly reduced susceptibility to interference. This significantly improves the interference sensitivity of the measuring device. Each individual signal in the differential transmission is equally susceptible to interference and can assume a "distorted" value depending on the interference.The difference between the two distorted signals corresponds to the signal to be transmitted and is not affected in the process, as both signals are distorted to exactly the same extent. This type of differential measurement is particularly suitable for the application of the invention in trailers with auxiliary drives.

[0025] According to a further preferred embodiment, the invention provides that the measuring device is designed as a capacitive sensor unit, wherein the individual distance sensors of the capacitive sensor unit are formed by capacitive sensor surfaces. Capacitive sensors are designed for contactless displacement measurements, distance measurements, and position measurement tasks, but are also used for thickness measurements of various materials. The capacitive distance sensor and the (movable) counter surface form an electrical capacitor, the distance between which determines the capacitance. The counter surface(s) can preferably be formed by the upper end of the journal shaft and / or the underside of the plate base. Thanks to their high signal stability and resolution, capacitive sensors are used for measuring tasks in laboratories and industry.Capacitive distance sensors advantageously provide highly reliable and precise position detection of objects made of virtually any material, regardless of gloss, reflectance, color, and surface texture. Capacitive sensors are also characterized by a long service life and can implement completely non-contact measurement principles.

[0026] The cross shape of the sensor proves particularly advantageous in the context of force measurement on the fifth wheel coupling because the cross shape, with its "cross tips," can be aligned on the plate-shaped mounting flange in the direction of the radial force components to be measured. The capacitive sensor unit can preferably be designed symmetrically, so that the cross shape can be created, for example, by four identical recesses. This simplifies manufacturing and reduces the production costs of the measuring device. At the same time, it ensures a radial measurement direction or alignment of the capacitive sensor surfaces or the distance sensors. The four capacitive surfaces preferably form the aforementioned "cross tips." By providing four capacitive surfaces, a sufficient number of measurements can be performed to fully determine the radial reaction forces in the vehicle's longitudinal and transverse directions.It is particularly preferred that at least four capacitive sensor surfaces are provided, which extend radially to the central axis and form a cross shape. This supports a precise and uniform measurement of the reaction forces on the fifth wheel coupling. Additionally, the cross shape can be used to determine additional force components between two sensor surfaces.

[0027] The invention also relates to a fifth wheel coupling with a kingpin as described above and below, wherein the fifth wheel coupling comprises a fifth wheel plate, and wherein the fifth wheel plate and the fifth wheel coupling are arranged to receive a kingpin on a tractor unit of a commercial vehicle.

[0028] The invention further relates to a commercial vehicle with a fifth wheel coupling and a kingpin as described above and below.

[0029] According to an alternative embodiment of the invention, additional sensors can be arranged between the at least four distance sensors for further segmentation and refinement of the measuring device. This can be particularly useful and advantageous when more precise measurements need to be performed as needed, or when additional force components located between the cross points are to be measured directly.

[0030] According to another alternative embodiment, for example, instead of an annular protrusion, an intermediate disk can be placed in the cavity to accommodate the measuring device, which shortens the distance between the underside of the plate base and the upper end of the journal shaft. According to this alternative embodiment, the upper end of the journal shaft and the underside of the plate base can advantageously be flat.

[0031] According to another alternative embodiment, the measuring device can be arranged directly at the upper end of the journal shaft. It is preferred that the entire face of the upper end of the journal shaft be flat to accommodate the measuring device. Conversely, the underside of the plate base can be provided with an annular protrusion extending toward the upper end of the journal shaft. This simplifies production and saves costs, among other things.

[0032] According to a further alternative embodiment, for example, the signal processing electronics can be designed separately from the measuring device or from the distance sensors of the measuring device, so that the signal processing electronics can be arranged not in the cavity but in an external area.

[0033] According to another alternative design variant, other types of contactless distance sensors, such as magnetic tape sensors, can be used for distance measurement instead of contactless capacitive distance sensors. Other sensor types and designs are also conceivable, provided that the desired dynamic driving loads can be determined.

[0034] Further features, details, and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. They show:

[0035] Fig. 1. a schematic oblique view of a kingpin according to the invention for coupling a trailer to a fifth wheel coupling of a tractor;

[0036] Fig. 2 is a partial plan view of a kingpin according to the invention and a schematic representation of the measuring device;

[0037] Fig. 3a is a bottom view of a kingpin according to the invention;

[0038] Fig. 3b is a cross-sectional view of a kingpin according to the invention.

[0039] Fig. 1 illustrates a kingpin, generally designated 10, for a fifth wheel coupling of a commercial vehicle. The kingpin 10 comprises a journal shaft 3 extending along a central axis M of the kingpin 10. The journal shaft 3 is provided with a journal head 2 at its lower end. During the coupling process, the lower end of the journal shaft 3 or the journal head 2 is aligned perpendicular to a roadway (not shown) and inserted and secured into the fifth wheel coupling (not shown) of the tractor.

[0040] At the opposite upper end of the PTO shaft 3, which faces a chassis or the underside of a trailer chassis, a fastening flange 4 and a plate-shaped receiving flange 5 for securing the kingpin 10 are arranged. The plate-shaped receiving flange 5 is usually pre-assembled to the trailer chassis with a material fit and can receive and secure the fastening flange 4 of the PTO shaft 3. For this purpose, the plate-shaped receiving flange 5 is placed onto the upper end of the PTO shaft 3 and fixed to the fastening flange 4. To fasten the PTO shaft 3 to the plate-shaped receiving flange 5, fixing means are arranged in the region of the fastening flange 4. The fixing means are designed as threaded screws 7 and are arranged at equal intervals in the circumferential direction around the PTO shaft 3.

[0041] By referring to Fig. 2, it can be seen that a measuring device for detecting driving dynamic reaction forces is provided on an upper side of the plate-shaped receiving flange 5, wherein the measuring device is designed as a capacitive sensor unit 20.

[0042] The capacitive sensor unit 20 is essentially disc-shaped and has a cross shape. The capacitive sensor unit 20 is arranged directly on the plate-shaped mounting flange 5. The plate-shaped mounting flange 5 normally has no opening on its upper side. A section of the capacitive sensor unit 20 is shown in plan view to illustrate it.

[0043] The capacitive sensor unit 20 further comprises four distance sensors that extend radially to the center axis M of the power take-off shaft 3. The distance sensors are designed as capacitive sensor surfaces S1, S2, S3, S4. The sensor surfaces S1, S3 extend radially to the center axis M and simultaneously in the vehicle's longitudinal direction FL. The sensor surfaces S1, S3 extend in opposite directions along the vehicle's longitudinal direction FL. The sensor surfaces S2, S4 extend radially to the center axis M and simultaneously in the vehicle's transverse direction FQ. The sensor surfaces S2, S4 extend in opposite directions along the vehicle's transverse direction FQ.

[0044] The capacitive sensor unit 20 also has signal processing electronics 22. The signal processing electronics 22 of the capacitive sensor unit 20 are arranged centered on the central axis M of the journal shaft 3. The signal processing electronics 22 are surrounded by the individual capacitive sensor surfaces S1, S2, S3, S4 radially to the central axis M.

[0045] In conjunction with Fig. 3a and Fig. 3b it can be seen that the plate-shaped

[0046] Receiving flange 5 and the fastening flange 4 are flanged to one another and releasably fixed to one another in such a way that the receiving flange 5 rests fully on the fastening flange 4 in the circumferential direction at the level of the threaded screws 7, so that a cavity 15 is bordered by the flanged surface.

[0047] It can also be seen that the capacitive sensor unit 20 is arranged in the cavity 15. In the fixed state, the cavity 15 is formed between the plate-shaped receiving flange 5 and the upper end of the journal shaft 3. The cavity 15 is essentially disc-shaped and, in particular, plate-shaped.

[0048] The plate-shaped receiving flange 5 has a plate base 8, wherein the plate base 8 has an underside facing the cavity 15 for receiving the capacitive sensor unit 20. The plate base 8 is arranged parallel to the upper end of the journal shaft 3, and the underside of the plate base 8 is flat. The capacitive sensor unit 20 is arranged, in particular, directly on the underside of the plate base 8. The capacitive sensor unit 20 rests over its entire surface on the underside of the plate base 8 and is fixed. The capacitive sensor unit 20 is further arranged plane-parallel to the underside of the plate base 8 and plane-parallel to the upper end of the journal shaft 3.

[0049] The plate base 8 of the receiving flange 5 also has a flat upper surface facing away from the cavity 15 for securing the receiving flange 5. The upper surface of the plate base 8 is usually firmly bonded to the trailer chassis (not shown). The underside of the chassis is arranged parallel to the roadway.

[0050] The upper end of the journal shaft 3 has an inner end face 6 facing the cavity 15, while the upper end of the journal shaft 3 has an outer end face 14 facing the cavity. Both end faces 6, 14 are flat and arranged centered relative to the central axis M. At the same time, the end faces 6, 14 are arranged parallel to the underside of the plate base 8.

[0051] The upper end of the journal shaft 3 further comprises an annular protrusion 9 extending toward the plate base 8, wherein the annular protrusion 9 is arranged between the inner end face 6 and the outer end face 14. The capacitive sensor unit 20 is arranged directly on the underside of the plate base 8, wherein the capacitive sensor unit 20 is positioned opposite the inner end face 6 and the annular protrusion 9. The measuring device or the capacitive sensor unit 20, the underside of the plate base 8, the inner and outer end faces 6, 14, and the annular protrusion 9 are all arranged centered relative to the central axis M.

[0052] The annular elevation 9 advantageously provides an annular surface opposite the capacitive sensor unit 20 or the capacitive sensor surfaces S1, S2, S3, S4 as a counter-measurement surface. The annular elevation 9 is flat on its annular surface facing the underside of the plate base 9.

[0053] The capacitive sensor unit 20 is designed to measure changes in distance relative to the upper end of the journal shaft 3 in order to be able to determine reaction forces acting radially to the central axis from the measured data. The capacitive sensor unit 20 is particularly designed to measure changes in distance relative to the annular elevation 9. As can be seen in particular from Fig. 3, the radial extension of the individual capacitive sensor surfaces S1, S2, S3, S4 corresponds to a radial extension of the annular elevation 9.

[0054] The invention is not limited to one of the previously described embodiments, but can be modified in a variety of ways. For example, several or fewer sensor positions can be provided on the capacitive sensor unit.

[0055] The kingpin according to the invention can generally be used to measure reaction forces on a coupling element between two vehicles. The invention primarily relates to the measurement of reaction forces acting on a fifth wheel coupling or on the kingpin of a trailer. The measurement serves to control and regulate a trailer's auxiliary drive. The invention can also be useful for controlling other types of drives in the trailer, such as hydraulic drive axles. Alternatively, the measuring device can be used at separate locations to measure driving resistance forces.

[0056] All features and advantages arising from the claims, the description, and the drawings, including structural details, spatial arrangements, and method steps, may be essential to the invention both individually and in a wide variety of combinations. Reference symbols list

[0057] M center axis kingpin 6 inner face

[0058] FL vehicle longitudinal direction 7 screws

[0059] FQ vehicle transverse direction 8 plate base

[0060] AA cross-sectional plane 9 annular elevation

[0061] 51 Capacitive sensor surface 10 Kingpin

[0062] 52 Capacitive sensor surface 14 outer face

[0063] 53 Capacitive sensor surface 15 Cavity

[0064] 54 Capacitive sensor area 20 Capacitive sensor unit

[0065] 22 Signal processing electronics

[0066] 2 tenon head

[0067] 3 PTO shaft

[0068] 4 Mounting flange

[0069] 5 Mounting flange

Claims

Patent claims Kingpin (10) for a fifth wheel coupling of a commercial vehicle, with a journal shaft (3) which extends along a central axis (M) and has a journal head (2) at its lower end, wherein the journal shaft (3) has a fastening flange (4) at its upper end facing away from the journal head (2), and with a receiving flange (5) which is placed on the upper end of the journal shaft (3) and is fixed to the fastening flange (4), characterized in that a measuring device is provided for detecting driving dynamic reaction forces, wherein the measuring device is arranged in a cavity (15) which, in the fixed state, is formed between the receiving flange (5) and the upper end of the journal shaft (3). Kingpin according to claim 1, characterized in that the measuring device has a cross shape, wherein the measuring device is substantially disc-shaped.Kingpin according to claim 1 or 2, characterized in that the upper end of the journal shaft (3) has an inner end face (6) facing the cavity (15), wherein the upper end of the journal shaft (3) has an outer end face (14) facing the cavity (15). Kingpin according to one of the preceding claims, characterized in that the upper end of the journal shaft (3) has an annular elevation (9). Kingpin according to one of the preceding claims, characterized in that the receiving flange (5) has a plate base (8), wherein the plate base (8) has an underside facing the cavity (15) for receiving the measuring device. Kingpin according to claim 5, characterized in that the measuring device is arranged plane-parallel to the underside of the plate base (8) and plane-parallel to the upper end of the journal shaft (3). Kingpin according to claim 5 or 6, characterized in that the measuring device is arranged and fixed directly on the underside of the plate base (8), wherein the measuring device is positioned opposite the inner end face (6) and the annular elevation (9). Kingpin according to one of the preceding claims, characterized in that the measuring device is designed to measure changes in distance with respect to the upper end of the journal shaft (3), wherein the measuring device comprises at least two distance sensors, preferably at least four distance sensors. Kingpin according to claim 8, characterized in that the measuring device has signal processing electronics (22), wherein the signal processing electronics are arranged centered to the central axis (M) of the journal shaft (3), and wherein the signal processing electronics (22) is surrounded by the individual distance sensors radially to the central axis (M).Kingpin according to claim 8 or 9, characterized in that the measuring device is arranged centered on the center axis (M) of the journal shaft (3), wherein the individual distance sensors of the measuring device extend radially to the center axis (M). Kingpin according to one of claims 8 to 10, characterized in that at least one distance sensor is aligned radially to the center axis (M) and in the vehicle's longitudinal direction (FL), wherein at least one further distance sensor is aligned radially to the center axis (M) and in the vehicle's transverse direction (FQ). Kingpin according to one of claims 8 to 11, characterized in that at least two distance sensors are aligned radially to the center axis (M) and in the vehicle's longitudinal direction (FL), wherein at least two further distance sensors are aligned radially to the center axis (M) and in the vehicle's transverse direction (FQ). Kingpin according to one of claims 8 to 12, characterized in that the measuring device is designed as a capacitive sensor unit (20), wherein the individual distance sensors of the capacitive sensor unit (20) are formed by capacitive sensor surfaces (S1, S2, S3, S4). A fifth wheel coupling with a kingpin according to one of the preceding claims, characterized in that the fifth wheel coupling comprises a fifth wheel plate, wherein the fifth wheel plate and the fifth wheel coupling are arranged to receive a kingpin on a tractor unit of a commercial vehicle. A commercial vehicle with a fifth wheel coupling and a kingpin according to claim 14.

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