Spherical joint bearing for an articulated vehicle, articulated vehicle and method for operating an articulated vehicle

Description

[0001] The invention relates to a spherical joint bearing for an articulated vehicle, an articulated vehicle and a method for operating an articulated vehicle.

[0002] Articulated vehicles with spherical joint bearings for connecting interconnected parts are known in the form of articulated buses or rail vehicles such as trams, streetcars, etc. These articulated or linkage vehicles have in common that they consist of several articulated, operationally inseparable parts or sections, between which passage is possible while the vehicle is in motion.

[0003] Spherical spherical bearings connect the components of articulated vehicles in such a way that they allow for both cornering maneuvers and, to a limited extent, pivoting about a longitudinal axis and a horizontal transverse axis of the articulated vehicle, thus enabling rotational, pitching, and roll movements. The two vehicle components are connected by a lower and an upper bearing housing of the spherical spherical bearing, respectively. These two bearing housings are spherically constructed in the relevant parts of the bearing, with concentric inner and outer spherical bearing surfaces, and can rotate relative to each other about a common center point. The bearing housings are connected to the vehicle components via bolted or screw-studded connections.

[0004] The amplitude of the rotational, pitching, and rolling movements possible with such spherical spherical joint bearings is limited partly by the joint bearing itself, but even more so by the dimensions of the articulated vehicle parts attached to it, such as articulated bus sections or tram cars. While rotational movements (curves) in the installed state of the spherical spherical joint bearing typically allow relative angles between the longitudinal axes of the vehicle parts of up to 20° to 30°, pitching and rolling movements are limited to smaller angles, for example, up to ±5°. Therefore, the upper and lower bearing housings are not actually spherical workpieces, even though the upper bearing housing is referred to as the "outer ball" in English, but rather workpieces with partially convex or convex surfaces.concave, overlapping spherical bearing surfaces, whose radii are chosen to be adapted to each other in order to achieve a large-area distribution of the forces acting on the bearing surfaces and to avoid point pressure peaks.

[0005] To prevent the upper bearing housing ("outer ball"), with its downward-facing convex spherical bearing surface, from being levered upwards out of the lower bearing housing, with its upward-facing concave spherical bearing surface, the lower bearing housing has a vertically upward-facing column at the center of its spherical bearing surface. An anti-lift device is mounted and fixed to the upper end of this column. This anti-lift device, also known as the "inner ball," has a spherical bearing surface on its underside. This anti-lift device acts like a cap, engaging with an upward-facing spherical bearing surface of the upper bearing housing and projecting radially beyond a central opening in the upper bearing housing.Under normal operating conditions, the weight of the vehicle section connected to the upper bearing housing presses the upper bearing housing onto the bearing surface of the lower bearing housing, and there is no contact between the upper bearing housing and the anti-lift device. Such contact only occurs if, during a pitching motion of the articulated vehicle, the upper bearing housing is pulled upwards and leaves the lower, actual spherical bearing surface. The anti-lift device must also be able to withstand strong forces in such cases.

[0006] Articulated vehicles are typically heavy vehicles, so the spherical bearings must withstand high loads. Therefore, these bearings are largely made of high-strength, corrosion-resistant steel. To enable the smoothest possible sliding motion, a lower spherical bearing surface is formed by a plastic liner, which, together with the steel, provides low sliding resistance. This plastic liner has a lower strength than the steel used in the rest of the spherical bearing and is therefore subject to significantly higher wear. If this plastic liner is worn, the bearing rattles, and driving safety deteriorates. Wear inspection during regular maintenance is therefore essential. However, measuring the wear of the spherical bearing is very complex, and accurate measurements are only possible on removed bearings.

[0007] In the event of overload, such as during an accident, the two bearing housings are subjected to intense, localized pressure against each other, which can damage the plastic liner. Furthermore, under heavy load, a screw connection of an anti-lift device, which secures the upper bearing housing from above against the lower bearing housing, can also be damaged.

[0008] US patent 2018 / 031446 A1 discloses a spherical spherical bearing whose liner has two wear sensors. These sensors each have two contacts that come into electrical contact with each other via a metallic bearing surface when the liner is worn.

[0009] Starting from this premise, it is an object of the present invention to make the operation of articulated vehicles with spherical joint bearings safer with less effort than before.

[0010] This problem is solved by a spherical articulated bearing for an articulated vehicle, comprising a lower bearing housing connectable to a first articulated vehicle section with a central vertical column, an annular plastic liner arranged around the column in the lower bearing housing, defining an upwardly open first spherical bearing surface, an annular spherical upper bearing housing connectable to a second articulated vehicle section, which slides on the first spherical bearing surface, and an anti-lift device with a second spherical bearing surface, which can be attached to a central column of the bearing housing and secures the upper bearing housing against lifting, wherein at least one wear sensor is integrated into the plastic liner, which, in a new state of the plastic liner, has a predefined distance to the first spherical bearing surface of the plastic liner, wherein the articulated bearing is further developed bythat the anti-lift device and / or one or more fastening screws with which the anti-lift device is fastened to the central column of the lower bearing housing are equipped with at least one sensor.

[0011] The predefined distance defines a wear limit, below which the plastic liner must be replaced. Because the point at which the wear limit is reached is automatically detected by one or more wear sensors, it is no longer necessary to disassemble the spherical joint bearing during every maintenance procedure. Instead, it is sufficient to do so only when the sensor signal indicates that the plastic liner is actually worn and requires replacement. The time-consuming and accurate measurement of wear during regular maintenance is also eliminated. Furthermore, the system immediately indicates if the plastic liner has been damaged by excessive stress, such as in an accident, and requires replacement. This makes operating the articulated vehicle with the spherical joint bearing safer and less complex.

[0012] The principle of wear sensors is known from vehicle brakes, especially disc brakes, where wear sensors are integrated into the brake pads. However, the operating conditions in brake pads differ fundamentally from those in spherical spherical bearings of articulated vehicles. In spherical bearings, there is a continuous and constant pressure load at extremely low relative speeds between the moving bearing components. In contrast, motor vehicle brakes are only ever used briefly, and due to the high relative speed between the brake disc and brake pads and the large braking force applied, significant wear occurs on the brake pads, while the vehicle's kinetic energy is converted into thermal energy in the brake disc.Primarily due to the abrasive effect of the rapidly rotating brake discs relative to the brake pads, wear sensors on vehicle brakes are typically designed as electrically conductive loops. These loops are positioned inwards within the brake pad around a wear limit and are very quickly severed by the rapidly rotating brake disc when the wear limit is reached. This interrupts the electrical connection as soon as the brake is released and the brake pads disengage from the brake disc. The sudden loss of conductivity in the sensor signals that the brake pad has reached its wear limit.

[0013] In spherical plain bearings, this would not work in the same way because the rapid relative movement between the bearing parts, which would allow a wire loop to be quickly and reliably severed, is absent. Therefore, in some embodiments, the wear sensor can be designed as a mutually insulated pair of wires that make electrical contact upon contact with an electrically conductive surface of the upper bearing housing. As long as the wire pair is embedded or integrated within the plastic liner, they are insulated from each other, while contact with the metallic spherical bearing surface of the upper bearing housing establishes the electrical contact. To ensure that the contact remains permanent, such a wear sensor can be embedded in the plastic liner at a point that remains in contact with the upper bearing housing in every relative position between the lower and upper bearing housings encountered during operation.Alternatively, a vehicle control unit may also provide that a register, for example a memory location or a flag, with which the wear sensor is monitored, is switched to a state indicating wear of the plastic liner when contact is first made at the wear sensor, and the register can only be reset after maintenance or replacement of the plastic liner.

[0014] Conversely, in some embodiments, the wear sensor is designed as a wire loop with a continuous electrical conductor. When the plastic liner wears, the wire loop is interrupted by a mechanically pressed interrupting element against the upper bearing housing, in particular by a sharp edge of the interrupting element or by breaking it at a predetermined breaking point. Such a pressurized interrupting element circumvents the problem that, unlike vehicle brakes, there is no highly abrasive effect from brake discs, which would otherwise inevitably cut the wire loop during braking due to their rapid rotation.

[0015] One implementation of such a solution involves holding a section of the wire loop, optionally designed with a smaller wire diameter than the rest of the loop to act as a predetermined breaking point, under suitable tension using mechanical holders or clamps, or resting on the surface of a rigid body also embedded in the plastic liner. A second rigid body is embedded in the plastic liner with its back side at the wear limit and its edge contacts the wire loop section. Once the wear limit is reached, pressure is exerted from the upper bearing housing onto the back side of the second rigid body, causing its edge to press against the corresponding prepared section. This causes the wire in that section to break, thus generating a wear signal.

[0016] The wires of the wear sensor can be guided vertically, horizontally, radially, and / or with a bend to the first spherical bearing surface of the plastic liner in various configurations. Manufacturing can be carried out by first casting or milling the plastic liner and then inserting one or more bores into which the one or more wear sensors are inserted. The bores can optionally be filled afterward to secure the one or more wear sensors. Alternatively, the wear sensor(s) can be already present in the mold during the casting of the plastic liner and cast directly into it. This also allows for other shapes for the wear sensors, for example, with curves or bends in the wire guides. Furthermore, this has the advantage that the wear sensors cannot slip within the plastic liner.

[0017] In various embodiments, multiple wear sensors can be arranged distributed around the circumference of the plastic liner. This makes it possible to monitor the wear of the plastic liner even in less stressed areas of the spherical bearing, such as the rear lateral areas, which may nevertheless be affected in accidents or other exceptional driving conditions.

[0018] According to the invention, the anti-lift device and / or one or more fastening screws with which the anti-lift device is attached to the central column of the lower bearing housing are equipped with at least one sensor. In various embodiments, the at least one sensor can be configured as a screw sensor, in particular with piezoelectric measuring elements, as a pressure sensor in the form of a washer, as a strain gauge, as a torsion sensor, or as a break sensor, in particular as an interruptible circuit. These types of sensors, usable as or with screws, are known and indicate in various direct or indirect ways when the screw loses its clamping force.This occurs in the anti-lift device of the spherical spherical bearing, especially under heavy loads that arise when the upper bearing housing is lifted off the lower bearing housing with a force exceeding the specifications of the spherical bearing, for example in the event of emergency braking or an accident.

[0019] For example, pressure sensors used as washers will register a brief pressure increase followed by a rapid pressure drop if the monitored screw breaks and therefore no longer exerts any tensile force. A twist sensor monitors whether the screw loosens in its threaded hole due to twisting, thus addressing a more gradual loosening of the screw connection, while strain gauges or fracture sensors directly monitor the functionality of the screw.

[0020] The problem underlying the invention is also solved by an articulated vehicle with a spherical articulated bearing as described herein and a control unit connected to at least one wear sensor and / or to at least one sensor on the anti-lift device or a screw of the anti-lift device. Such an articulated vehicle implements the same advantages, properties, and features as the articulated bearing according to the invention.

[0021] Furthermore, the problem underlying the invention is also solved by a method for operating a previously described articulated vehicle with a previously described spherical articulated bearing according to the invention, in which the control unit monitors whether a wear sensor indicates wear of the plastic liner and / or whether a sensor on the anti-lift device or a screw of the anti-lift device indicates loosening of the anti-lift device. This method also realizes the same advantages, properties, and features as the other aspects of the invention.

[0022] In embodiments, in the event of damage to the articulated bearing indicated by a signal from a wear sensor or a sensor on a screw of the anti-lift device, the control unit generates a message about the damage to the articulated bearing and displays this message to a vehicle operator, stores it for later reading and / or transmits it to an external computer, in particular a computer of a maintenance system for the articulated vehicle.

[0023] Further features of the invention will become apparent from the description of embodiments according to the invention, together with the claims and the accompanying drawings. Embodiments according to the invention may fulfill individual features or a combination of several features.

[0024] Within the scope of the invention, features marked with "in particular" or "preferably" are to be understood as optional features.

[0025] The invention is described below, without limiting the general concept, with reference to exemplary embodiments and the drawings, whereby for all details of the invention not explained in detail in the text, explicit reference is made to the drawings. The drawings show: Fig. 1 a schematic representation of a cross-section through a spherical articulated bearing for an articulated vehicle, Fig. 2 a schematic exploded view of the articulated bearing of the Fig. 1 , Fig. 3 a schematic top view of the upper side of the joint bearing of the Fig. 1 , Fig. 4 a schematic representation of a spherical joint bearing arranged between two parts of an articulated vehicle and Fig. 5 a schematic representation of an embodiment of a joint bearing of an articulated vehicle.

[0026] In the drawings, identical or similar elements and / or parts are provided with the same reference numbers, so that a re-presentation is omitted.

[0027] Fig. 1Figure 1 shows a schematic cross-section through a known spherical articulated bearing 20 for an articulated vehicle, such as an articulated bus or tram. The articulated bearing 20 comprises a lower bearing housing 1, which is essentially rotationally symmetrical about a central vertical axis (not shown). The lower bearing housing 1 is provided with several threaded holes 1.6 for connection to a first vehicle component of an articulated vehicle. Furthermore, the lower bearing housing 1 has a central, vertically oriented column 1.1 and a seat 1.2 arranged circumferentially around the central column 1.1. An annular plastic liner 4 is received with its outer and underside surfaces in the circumferentially arranged seat 1.2 of the lower bearing housing 1 and defines a first spherical bearing surface 4.1 on an upwardly and inwardly facing surface.The plastic liner 4 can, for example, be fixed in the lower bearing housing 1 by frictional engagement. Alternatively, the plastic liner 4 can also be glued or screwed in place.

[0028] An annular upper bearing housing 5 is provided with additional threaded screw holes 5.3 for connection to a second vehicle component of an articulated vehicle. The upper bearing housing 5 is slidably mounted on the first spherical bearing surface 4.1 by means of an outwardly and downwardly projecting first spherical section 5.1 of an outer surface. Since the radius of the first spherical section 5.1 of the upper bearing housing 5 is adapted to, and in particular corresponds to, the radius of the first spherical bearing surface 4.1 of the plastic liner 4, the upper bearing housing 5 bears over a large area on the first spherical bearing surface 4.1 of the plastic liner 4. This prevents harmful localized pressure peaks.

[0029] The contact between the upper bearing housing 5 and the plastic liner 4 is inherently low-friction. To further reduce friction, one or more radially extending through openings 14 are provided, penetrating an outer wall of the lower bearing housing 1 and the plastic liner 4. A bearing lubricant can be introduced through these openings and distributed via a circumferential lubrication groove 4.2 over the first spherical bearing surface 4.1. The circumferential lubrication groove 4.2 is shown in the exploded view of the Fig. 2 to recognize.

[0030] Back in Fig. 1It can be seen that the first spherical section 5.1 of the upper bearing housing 5 extends further in the section plane than the first spherical bearing surface 4.1 of the plastic liner 4. This ensures that in every driving situation, i.e., in every permissible orientation of the upper bearing housing 5 relative to the lower bearing housing 1, the pressure load is always distributed over the entire spherical bearing surface 4.1 of the plastic liner 4, and thus no different pressure loads can occur on directly adjacent parts of the plastic liner 4 that could lead to cracking in the plastic liner 4.

[0031] At the same time, in Fig. 1It can be seen that tilting and rocking movements of the upper bearing housing 5 relative to the lower bearing housing 1 are limited by the fact that, if the inclination is too great, the underside of the upper bearing housing 5 abuts the outer surface of the central column 1.1 of the lower bearing housing 1. For this purpose, the outer surface of the column 1.1 and the inner surface of the central opening of the annular upper bearing housing 5 are each conically shaped, with the opening angles or cone angles being coordinated to achieve the most extensive contact possible when impacting the central column and thus the largest possible distribution of the mechanical load, in order to prevent damage from localized pressure peaks on the bearing housings.

[0032] The upper bearing housing is bounded at the top by an anti-lift device 6, which is attached to a surface 1.2 of the central column 1.1 of the lower bearing housing 1. The anti-lift device 6 projects radially beyond both the central column 1.1 and the central opening of the upper bearing housing 5. For centering on the central column 1.1, the anti-lift device 6 has a circumferential rim on its underside that projects vertically downwards along its circumference beyond the central column 1.1. In addition to the attachment on the top of the central column 1.1, the anti-lift device 6 has through holes 6.1 with screw head seats that align with corresponding threaded holes 11 in the surface 1.2 of the central column 1.1. Fastening is achieved with fastening screws 7, which pass through the holes 6.1 into the threaded holes 11.7 are inserted and screwed in, with the heads of the fastening screws 7 resting on the screw head seats of the screw holes 6.1. As shown in the . Figures 2 and 3 As can be seen, the anti-lift device 6 is attached in this example with five fastening screws.

[0033] The anti-lift device 6 has a second spherical bearing surface 6.2 on its downward-facing surface, which is opposite a second spherical section 5.2 of the upper bearing housing 5. The radii of the second spherical bearing surface 6.2 and the second spherical section 5.2 correspond to each other, so that under any inclination of the spherical bearing 20, a large-area contact and distribution of the acting forces occurs. Furthermore, the second spherical bearing surface 6.2 and the second spherical section 5.2 are concentric with the first spherical bearing surface 4.1 and the first spherical section 5.1.

[0034] The spherical plain bearing 20 is sealed at the top by means of a circumferential sealing lip 13 made of rubber or another flexible material. This lip is attached to the upper outer edge of the wall of the lower bearing housing 1 by means of a circumferential bead at its edge in a circumferential groove 1.4, and also rests on a circumferential shoulder on the upper bearing housing 5. The attachment can be achieved, for example, by frictional engagement between the elastic material of the sealing lip 13 and a cylindrical protruding part of the upper bearing housing 5, the diameter of which is slightly larger than the diameter of a central opening in the sealing lip 13 in its relaxed state, through which the protruding part of the upper bearing housing 5 extends.

[0035] The Figures 2 and 3 show the spherical joint bearing 20 in an exploded view ( Fig. 2 ) and a top view ( Fig. 3These illustrations reveal the rotationally symmetrical structure of the spherical bearing 20 and its individual parts, which are in Fig. 1 are shown in cross-section.

[0036] Fig. 4 shows a similar example of a spherical joint bearing 20, in which, in addition to the details that the Figs. 1 to 3 The arrangement of the spherical spherical bearing 20 in the articulated vehicle is shown. The spherical spherical spherical bearing 20 sits with its lower bearing housing 1 in a receptacle of a lower vehicle frame 3 of a first part of an articulated vehicle, and is fastened to the lower vehicle frame by a plurality of fastening screws 2.

[0037] An upper vehicle frame 9 is attached from above to the top of the upper bearing housing 5 by means of a plurality of fastening screws 8, which is attached to a central column 1.1 of the lower bearing housing 1 by means of an anti-lift device 6.

[0038] The Fig. 5shows based on the in Fig. 4 The spherical joint bearing 20 shown represents several possible implementations of the wear and damage measurement according to the invention, which can be realized cumulatively.

[0039] The anti-lift device 6 has a centrally located sensor 10 that extends into the surface of the central column of the lower bearing housing 1, on which the anti-lift device 6 rests and is fastened. This sensor can be a breakage sensor that breaks as soon as the anti-lift device 6 is lifted from the central column. The sensor 10 can also be a strain gauge or a smart screw. Furthermore, the sensor 10 does not have to be located in the center of the anti-lift device, but can be eccentrically positioned, or several sensors 10 can be distributed across the surface of the anti-lift device 6. The fastening screws 7, with which the anti-lift device 6 is secured, can also be directly monitored. For this purpose, pressure sensors in the form of washers, smart screws, breakage sensors, strain gauges, or similar devices can be used.As soon as such a sensor 10 detects that the anti-lift device 6 or a fastening screw 7 of the anti-lift device is no longer secure, damage to the articulated bearing 20 is detected and appropriate measures are taken, such as informing the vehicle operator or a maintenance system.

[0040] For the wear sensors 11, it shows Fig. 5 Three different possible variants, A, B, and C, are located within the plastic liner 4 and differ primarily in their cable routing in these embodiments. Each variant is shown in an enlarged section.

[0041] In variant A, shown in Fig. 5In the cutout at the bottom left, the wires of the wear sensor 11 are guided from below and inwards under a bend until they reach the wear limit 12. The wires pass through a designated vertical bore through the plastic liner 4, the lower bearing housing 1, and the lower vehicle frame 3, for example, to a central control unit or an electronic unit of the sensor 11 connected to the central control unit. Due to the bend, the two wires approach the spherical bearing surface of the plastic liner 4 almost radially. When the wear of the bearing surface has progressed to the point that the wear limit 12 is reached or exceeded, both wire ends of the wear sensor 11 come into contact with the metallic wall of the upper bearing housing 5. The establishment of this electrical contact signals that the wear limit has been exceeded.

[0042] Variant B, in Fig. 5The version shown in the center below differs from variant A in that the wires of the wear sensor 11, which are fed from below, do not bend. This allows the two ends to be brought almost tangentially to the bearing surface of the plastic liner 4, while maintaining the distance to the bearing surface defined by the wear limit 12. The two wires therefore end at different heights. When the wear limit 12 is penetrated, the two wires are contacted laterally by the spherical surface of the upper bearing housing 5, and the electrical connection that signals wear is established.

[0043] In variant C, in Fig. 5As shown in the upper left, the wires of the wear sensor 11 are brought in from the side and, in extension, led away through the gap between the lower vehicle frame 3 and the upper vehicle frame 9. As in variant A, the wires in this case approach the wear limit or the bearing surface approximately radially. Reference symbol list

[0044] 1 Lower bearing housing 1.1 Central column 1.2 Column surface 1.3 Seat for plastic liner 1.4 Circumferential groove 1.5 Circumferential lubrication groove 1.6 Blind hole with internal thread 1.7 Blind hole with internal thread 2 Mounting screw 3 Lower vehicle frame 4 Plastic liner 4.1 First spherical bearing surface 4.2 Circumferential lubrication groove 5 Upper bearing housing 5.1 First spherical section 5.2 Second spherical section 5.3 Blind hole with internal thread 6 Anti-lift device 6.1 Screw hole with screw head seat 6.2 Second spherical bearing surface 7 Mounting screw 8 Mounting screw 9 Upper vehicle frame 10 Sensor 11 Wear sensor 12 Wear limit 13 Sealing lip 14 Opening 20 Spherical bearing

Claims

1. A spherical joint bearing (20) for an articulated vehicle, comprising a lower bearing housing (1) which can be connected to a first articulated vehicle section and which has a central vertical column (1.1), an annular plastic liner (4) which is arranged about the column (1.1) in the lower bearing housing (1) and which defines an upwardly open first spherical bearing surface (4.1), an annular spherical upper bearing housing (5) which can be connected to a second articulated vehicle section and which is slidingly mounted on the first spherical bearing surface (4.1), as well as an anti-lift device (6) having a second spherical bearing surface (6.2) which can be fastened to a central column (1.1) of the bearing housing and secures the upper bearing housing (5) against being lifted off, wherein at least one wear sensor (11) is integrated into the plastic liner (4), which, in a new condition of the plastic liner (4), is a predefined distance (12) from the first spherical bearing surface (4.1) of the plastic liner (4), characterized in that the anti-lift device (6) and / or one or more fastening screws (7), with which the anti-lift device (6) is fastened on the central column (1.1) of the lower bearing housing (1), is or are equipped with at least one sensor (10).

2. The spherical joint bearing (20) according to Claim 1, characterized in that the wear sensor (11) is configured as a pair of wires insulated from one another, which form an electrical contact on contact with an electrically conductive surface of the upper bearing housing (5).

3. The spherical joint bearing (20) according to Claim 1, characterized in that the wear sensor (11) is configured as a wire loop having a continuous electrical line, wherein when wear occurs to the plastic liner (4), the wire loop is interrupted by means of an interruption means which is pressed on mechanically by the upper bearing housing (5), in particular by being cut off by means of a sharp edge of the interruption means or by being broken at a predetermined breaking point.

4. The spherical joint bearing (20) according to Claim 2 or 3, characterized in that the wires of the wear sensor (11) are guided vertically, horizontally, radially and / or with a kink to the first spherical bearing surface (4.1) of the plastic liner (4).

5. The spherical joint bearing (20) according to any one of Claims 1 to 4, characterized in that multiple wear sensors (11) are arranged in a distributed manner in the circumferential direction of the plastic liner (4).

6. The spherical joint bearing (20) according to any one of Claims 1 to 5, characterized in that the sensor (10) is designed as a screw sensor, in particular with piezoelectric measuring elements, as a pressure sensor in the form of a washer, as a strain gauge, as a torsion sensor or as a fracture sensor, in particular as an interruptible circuit.

7. An articulated vehicle with a spherical joint bearing (20) according to any one of Claims 1 to 6 as well as a control unit which is connected to the at least one wear sensor (11) and / or to the at least one sensor (10) on the anti-lift device (6) or a screw (7) of the anti-lift device (6).

8. A method for operating an articulated vehicle according to Claim 7 with a spherical joint bearing (20) according to any one of Claims 1 to 6, characterized in that it is monitored by means of the control unit whether a wear sensor (11) displays wear of the plastic liner (4) and / or a sensor on the anti-lift device (6) or on a screw (7) of the anti-lift device (6) displays a loosening of the anti-lift device (6).

9. The method according to Claim 8, characterized in that, in the event of damage to the joint bearing (20) displayed by a signal of a wear sensor (11) or of a sensor on a screw (7) of the anti-lift device (6), the control unit generates a message regarding the damage to the joint bearing (20) and displays said message to a vehicle driver, stores it so that it can be read out later, and / or transmits it to an external computer, in particular a maintenance system for the articulated vehicle.