Trailer stabilization system for a vehicle trailer with speed sensor

Description

[0001] The invention relates to a trailer stabilization system for a vehicle trailer, in particular for a caravan, transport or boat trailer, according to the preamble of claims 1, 4 and 6.

[0002] Trailer stabilization systems of this type are known to prevent unstable driving conditions of the trailer, especially swaying movements. This is achieved by applying the wheel brakes of the trailer when swaying occurs, thus straightening the vehicle combination and counteracting the swaying motion.

[0003] The detection of swaying movements is typically achieved using acceleration sensors, which send corresponding swaying signals to an electronic control unit that controls a brake actuator. In braking systems with mechanical brake force transmission, the braking force generated by the brake actuator is then transmitted to the wheel brakes, for example, via cables in the form of Bowden cables.

[0004] It is of great importance that the braking force transmitted to the wheel brakes, i.e., the brake clamping force, does not cause the trailer wheels to lock up. As is well known, locked trailer wheels prevent sufficient lateral forces from being transmitted to the road surface, which can intensify swaying movements and cause the trailer to break away sideways. This is particularly critical if the trailer wheel that is subjected to greater stress due to the trailer's rolling movements locks up.

[0005] Whether a trailer wheel locks up depends heavily on the load and thus the trailer's weight, as well as the road surface and its coefficient of friction. With light, unloaded trailers and slippery surfaces, such as snow and ice, even relatively low braking forces can cause the trailer wheels to lock. With heavy, loaded trailers and surfaces with good grip, locking of the trailer wheels only occurs at higher braking forces.

[0006] In known trailer stabilization systems for overrun-braked trailers that operate without regard to load, the brake clamping force is constant and calibrated to the trailer's unladen weight. The use of such trailer stabilization systems is therefore limited to trailers with a relatively small difference between unladen weight and permissible gross vehicle weight.

[0007] A trailer stabilization system is already known from EP 3176042 A1, in which the axle load of the trailer is measured in order to adjust the brake clamping forces to the trailer's load condition. However, this system does not take into account the friction conditions between the road surface and the trailer wheels, so that even there, the locking of a trailer wheel when the stabilization system intervenes cannot always be reliably prevented.

[0008] A trailer stabilization system according to the preamble of claims 1, 4, and 6 is already known from DE 202021102632 U1. This system uses a pulse detection device arranged in the area of ​​the brake hub or brake drum, comprising a pole wheel and a magnetic field sensor, to detect the rotational speed of a trailer wheel and to control the brake actuator depending on the detected rotational speed. This also allows for the detection of a trailer wheel locking up. The pole wheel is equipped with permanent magnets attached to a cup-shaped carrier that can be mounted between the rim of the trailer wheel and an outer end face of the brake hub or brake drum. Further details regarding the mounting of the magnetic field sensor are not provided in this document.

[0009] Furthermore, WO 2018 / 219 894 A1 discloses a pole wheel which is part of an anti-lock braking system of a motor vehicle.

[0010] The invention is based on the objective of creating a trailer stabilization system of the type mentioned above, in which the speed sensor of the speed detection device, which interacts with the flywheel, can be attached to the vehicle trailer in the simplest, most space-saving and preferably retrofittable way possible.

[0011] This problem is solved according to the invention by a trailer stabilization system having the features of claims 1, 4 and 6. Advantageous embodiments of the invention are described in the further claims.

[0012] The trailer stabilization system according to the invention comprises a speed detection device for determining the rotational speed of at least one trailer wheel, wherein the speed detection device comprises a pole wheel connected to a brake hub or brake drum of a wheel brake of the vehicle trailer, and at least one speed sensor interacting with the pole wheel. Furthermore, the trailer stabilization system comprises an electronic control unit connected to the speed detection device for controlling at least one brake actuator to generate a braking force and to brake the at least one trailer wheel by means of the wheel brake depending on the detected rotational speed of the trailer wheel.

[0013] Furthermore, in the trailer stabilization system according to claim 1, the speed sensor is attached to a sensor holder which is attached to an axle stub of a trailer axle which serves to support the brake hub or brake drum.

[0014] According to an advantageous embodiment, the sensor holder has a clamping device in the form of a clamping collar for clamping the axle stub and securing the sensor holder to the axle stub. This allows the sensor holder to be attached to the brake hub or brake drum in a very simple, retrofittable, and detachable manner. Clamping elements in the form of screws are expediently used to tighten the clamping collar.

[0015] Advantageously, one half of the clamping clamp is connected in one piece to a boom that extends from the clamping clamp to the flywheel.

[0016] In the trailer stabilization system according to claim 4, the speed sensor is attached to a sensor holder which is attached to a cable entry point of a brake carrier plate. For example, the sensor holder can be welded to the cable entry point and extend from there to the circumferential ring of the flywheel in which the recesses / depressions and ribs are located.

[0017] Preferably, the cable insertion nozzle comprises a first retaining shell attached to the brake carrier plate and a second retaining shell detachably connected to the first retaining shell, wherein the sensor holder is attached to the detachable second retaining shell.

[0018] In the trailer stabilization system according to claim 6, the speed sensor is attached to a sensor holder which is attached to a brake carrier plate in the area of ​​a viewing hole provided in the brake carrier plate in such a way that the speed sensor is directed through the viewing hole towards the flywheel.

[0019] The invention is explained in more detail below with reference to the drawings. They show: Figure 1: a top view of a vehicle trailer chassis with a trailer stabilization system according to the invention; Figure 2: a view obliquely from below of the actuator and surrounding components; Figure 3: a partially cut-out view from below of the in Figure 2 shown parts; Figure 4: a spatial representation of a brake hub with flywheel; Figure 5: a longitudinal section through the brake hub of Figure 4 Figure 6: Detail VI of Figure 5on an enlarged scale; Figure 7: a longitudinal section through the brake hub of Figure 4 in isolation; Figure 8: Detail VIII of Figure 7 on an enlarged scale; Figure 9: a front view of the flywheel; Figure 10: a side view of the flywheel Figure 9 Figure 11, detail XI of Figure 10 on an enlarged scale; Figure 12: a spatial representation of a brake hub with a second embodiment of the flywheel according to the invention; Figure 13: detail XIII of Figure 12 on an enlarged scale; Figure 14: a spatial representation of a pole wheel with a third embodiment of the pole wheel according to the invention, wherein a wheel sensor is additionally shown; Figure 15: a trailer wheel with a pole wheel, a brake carrier plate and a wheel sensor, which is attached to a mounting bracket placed on a cable entry fitting; Figure 16: an end view of the arrangement of Figure 15without tire and rim; Figure 17: an upper half of the cable entry fitting with attached mounting bracket for the wheel sensor; Figure 18: a front view of a brake hub with brake carrier plate, flywheel, speed sensor and sensor holder, which is attached to an axle stub by means of a clamping device; Figure 19: a three-dimensional representation of the arrangement of Figure 18 without brake carrier plate and axle stub; Figure 20: the sensor holder of the Figures 18 and 19 in isolation; and Figure 21: a trailer wheel from the side of the brake carrier plate, wherein the speed sensor is attached in the area of ​​a viewing hole of the brake carrier plate.

[0020] In Figure 1 A chassis 1 for an overrun-braked vehicle trailer, for example a caravan trailer, is shown.

[0021] The chassis 1 comprises two lateral longitudinal members 2, which are intersected by a transverse axle tube 3. Within the axle tube 3, one or two rocker arms are rotatably mounted, in particular by means of rubber cords, within limited rotational range. Rocker arms 4 are fixed to the outer ends of the rocker arm(s) in a rotationally fixed manner. Axle stubs 5, which serve to mount wheel brakes 6, are attached to the rocker arms 4 in a known manner. In the illustrated embodiment, the wheel brakes 6 are designed as drum brakes, to which trailer wheels 29 are attached in a known manner.

[0022] From the longitudinal beams 2, drawbars 7 extend to the front end area of ​​the vehicle trailer, where a towing ball coupling 8, an overrun device 9 of an overrun brake system 10 and a handbrake lever 11 of a parking brake are located.

[0023] The braking force generated by the overrun device 9 and the handbrake lever 11 is transmitted to the wheel brakes 6 via a mechanical brake force transmission device. This mechanical brake force transmission device comprises a central brake linkage 12, which is connected at its front end to a transmission lever (not shown) of the overrun brake system 10 and at its rear end to a compensating balance 13, which is located in the Figures 2 and 3The compensating balance 13 advantageously consists of a rigid profile element, which is penetrated centrally by the brake linkage 12 and engaged from behind by a nut screwed onto the brake linkage 12. Cables 14 of two Bowden cables 15a, 15b are attached to the two opposite end regions of the compensating balance 13 and are led laterally outwards to the wheel brakes 6. The cables 14 are connected to the wheel brakes 6 in a known manner such that pulling on the cables 14 actuates the wheel brakes 6.

[0024] To reduce swaying movements of the vehicle trailer, a trailer stabilization system is provided, which is particularly important in the Figures 2 and 3This trailer stabilization system is shown in more detail below. It comprises a central unit 16, which is attached, in particular bolted, to a perforated plate 18 of the axle tube 3 by means of a mounting bracket 17. In the illustrated embodiment, the perforated plate 18 extends downwards from the axle tube 3 and is welded to the axle tube 3 centrally between the longitudinal members 2.

[0025] The central unit 16 comprises an actuator 19 in the form of an electric motor, which is connected via gear elements to a pull rod 20 ( Figure 3 ) acts to counteract these in the case of swaying movements to the rear, i.e. in Figure 3to pull to the right. The front end of the pull rod 20 is rigidly connected to a sliding cable sheath abutment 21, to which the ends 22 of the cable sheaths 23 of the Bowden cables 15a, 15b are attached. In the illustrated embodiment, the cable sheath abutment 21 is designed as a rigid, U-shaped profile element in cross-section. The cable sheaths 23 extend with their ends 22 through holes in the cable sheath abutment 21 and are secured there by means of screws. The cables 14 extend further forward through holes in the perforated plate 18 and can thereby be secured to the compensating balance 13.

[0026] The trailer stabilization system further includes a sway sensor (not shown in detail), which can also be located in the central unit 16 and generates corresponding sway signals in the event of a swaying movement of the vehicle trailer. Such a sway sensor could, for example, be a lateral acceleration sensor or a yaw sensor.

[0027] An electronic control unit, also located in the central unit 16, processes the sway signals received from the sway sensor and generates corresponding control signals for the actuator 19. The actuator 19 then actuates the mechanical brake force transmission device based on these control signals. This occurs when swaying movements are detected. The actuator 19 pulls the drawbar 20, and consequently the ends 22 of the cable sheaths 23, backwards via the cable sheath abutment 21, thereby applying the wheel brakes 6. The resulting braking of the trailer straightens the vehicle combination and reduces the swaying movements of the trailer.

[0028] The Figures 4 and 5 Figure 1 shows a spatial representation or longitudinal section of a brake hub 24 with a flywheel 25 according to the invention. Figure 5For the sake of clarity, some parts, such as brake pads, have been omitted.

[0029] The brake hub 24 is designed as a drum brake. The brake hub 24 has a circumferential wall 26 with an inner circumferential surface 27 and an outer circumferential surface 28. When the brake is applied, the brake shoes (not shown) bear against the inner circumferential surface 27. A portion of the outer circumferential surface 28 is designed as a mounting surface 29 for attaching the flywheel 25. An outer end wall 30 of the brake hub 30 serves, in a known manner, for fitting and tightening a rim (not shown).

[0030] A hollow cylindrical hub section 31 extends axially inwards from the outer end wall 30, on which the brake hub 24 is rotatably mounted on the axle stub 5 via bearings 32. The axis of rotation is designated 33.

[0031] Out of Figure 5A stationary brake support plate 34 is also visible, on which the brake linings are held and supported in the usual manner. Furthermore, a cable guide 35 is attached to the brake support plate 34, through which the cable 14 is guided to a mechanical actuating device located inside the brake hub 24 for actuating the brake shoes. The cable guide 35 extends a short distance axially beyond the brake support plate 34 towards the center of the trailer.

[0032] From the Figures 6 to 8It is evident that the mounting surface 29 provided on the outer circumferential surface 28 of the brake hub 24 is a concentric cylindrical surface that is relatively narrow, i.e., it occupies only a relatively small portion of the outer circumferential surface 28 in the axial direction. Preferably, as shown, the mounting surface 29 is located on a circumferential radial projection 36 of the circumferential wall 26, which extends radially outwards beyond the remaining portion of the outer circumferential surface 28. The mounting surface 29 is preferably a machined surface, which can be produced, for example, by machining on a lathe, by milling, or by grinding with high dimensional accuracy. This is particularly advantageous when, as is usual, the brake hub 24 consists of a single casting.

[0033] The mounting surface 29 is preferably limited axially outwards by a radially projecting web 37, which forms an axial stop for the flywheel 25. In this way, the flywheel 25 can be mounted as shown in Figure 6 As shown, the brake hub 24 can be easily slid onto the mounting surface 29 from its inner end until it abuts the rib 37. This allows for precise axial positioning of the flywheel 25 in a simple manner.

[0034] In the illustrated embodiment, the mounting surface 29 is further located in the axial half of the circumferential wall 26 which adjoins the inner end face 38 and a circumferential edge region 39 of the brake hub 24, over which an edge 40 of the brake carrier plate 34 extends overlapping at a distance.

[0035] The Figures 9 and 10 show the flywheel 25 in isolation, while Figure 11 detail XI of Figure 10shown in an enlarged view. The pole wheel 25 of this embodiment is designed as an annular, deep-drawn sheet metal element with a cross-section that is at least substantially L-shaped. In the vertical leg 41 of the pole wheel 25, a plurality of recesses 42 are arranged, preferably at equal intervals and regularly distributed over the entire circumference of the pole wheel 25. Between the recesses 42 are webs 43. The pole wheel 25, which rotates together with the brake hub 24, therefore causes changes in the magnetic field when the recesses 42 and webs 43 are in contact with a surface in the Figures 1 to 11 The speed sensor (not shown) is guided past the speed sensor. Based on these magnetic field changes, the speed sensor sends corresponding pulses to an electronic control unit 44 ( Figure 1 ) which can be located in the central unit 16. This allows the rotational speed of the trailer wheel to be determined and a blockage of the trailer wheel to be detected.

[0036] The flywheel 25 further comprises a closed circumferential mounting collar 25, which extends at least predominantly in the horizontal direction, i.e., concentrically to the axis of rotation 33. In the illustrated embodiment, the mounting collar 25 has a stepped diameter. The diameter in the free edge region is smaller than in an adjoining axial section 46 and is designed as a mounting edge 47, the inner diameter of which is matched to the diameter of the mounting surface 29 such that the mounting edge 47 can be pressed onto the mounting surface 29 of the brake hub 24 with a press fit and is thereby firmly fixed to the brake hub 24.

[0037] The axial section 46 of the fastening collar 45 has a diameter such that it extends over the edge 40 of the brake carrier plate 34 at a radial distance without contact.

[0038] The Figures 12 and 13Figure 2 shows a second embodiment of a flywheel 25' according to the invention. This flywheel 25' has essentially the same contour as the flywheel 25 of the first embodiment, so reference is made to the preceding descriptions in this regard. In contrast to the first embodiment, however, the flywheel 25' is not designed as a closed, circumferential ring, but as an annular clamping bracket with two spaced-apart ends 48a, 48b, which can be clamped together by means of a clamping device in the form of a screw 49. For this purpose, the flywheel 25' has a bracket 50a with a through-hole at end 48a, through which the screw 49 passes, and a bracket 50b with an internal thread at the other end 48b, into which the screw 49 can be screwed.

[0039] The brake hub 24 of this embodiment can again be designed in the same way as the brake hub 24 of the first embodiment and, in particular, has the preferably machined mounting surface 29 of the first embodiment, onto which the mounting edge 47 of the flywheel 25' can be placed. In contrast to the first embodiment, however, the flywheel 25' can initially be placed on the mounting surface 29 with a certain radial play. By subsequently screwing the screw 49 into the bracket 50b, the flywheel 25' is then clamped onto the mounting surface 29.

[0040] Figure 14Figure 1 shows a third embodiment of a flywheel 25" according to the invention. In this embodiment, the flywheel 25" is formed on the inner end face of the brake hub 24. The recesses 42 and webs 43 form an end-face toothed ring. This flywheel 25" can be manufactured, for example, by appropriate milling of the inner end face 38 of the brake hub 24.

[0041] Out of Figure 14 A speed sensor 51 is also visible, which is aligned with the flywheel 25'' in a direction parallel to the axis of rotation 33 of the brake hub 24. The speed sensor 51 can be connected to an electrical connection cable via a plug connector 52.

[0042] The following will be based on the Figures 15 to 21 Various retrofittable brackets for the speed sensor 51 are described.

[0043] Figure 15Figure 53 shows a spatial representation of a trailer wheel 53 with a view from the inside of the vehicle trailer, showing the axle stub 5, the brake carrier plate 34 and the speed sensor 51. Figure 16 shows a front view of the embodiment of Figure 15 without trailer wheel 53, Figure 17 shows the bracket for the speed sensor 51 and the upper half of the cable entry fitting 35 in isolation.

[0044] In this embodiment, the speed sensor 51 is attached to a sensor holder 54 in the form of a mounting bracket, which extends radially outwards from the cable entry fitting 35 to the flywheel 25, 25'. Preferably, the sensor holder 54 is welded to an upper mounting bracket 35b of the cable entry fitting 35. This upper mounting bracket 35b can be designed as a plug-in component and detachably connected to a lower mounting bracket 35a of the cable entry fitting 35, which is welded to the brake carrier plate 34. As shown in particular in Figure 17 As can be seen, a mounting sleeve 55 is arranged at the radial outer end of the sensor holder 54, into which the speed sensor 51 can be inserted.

[0045] The Figures 18 to 20Figure 51 shows a second embodiment of a sensor holder. In this embodiment, the speed sensor 51 is attached to a sensor holder 56, which is clamped onto the axle stub 5. For this purpose, the sensor holder 56 has a clamping device in the form of a clamping collar 57, which consists of two halves 57a, 57b. The halves 57a, 57b can be tightened together over the axle stub 5 by means of screws 58 and thereby clamped onto it.

[0046] Half 57a of the clamping clamp 57 is integrally connected to a rod-shaped extension 59, which extends radially outwards to the flywheel 25, 25'. The mounting sleeve 55 for inserting the speed sensor 51 is located at the radially outer end of the extension 59.

[0047] Figure 21Figure 1 shows a third embodiment of a sensor holder. The sensor holder 60 shown therein is attached in or to a viewing hole 61 of the brake carrier plate 34 such that the speed sensor 51 can be seen through the viewing hole 61 onto the recesses 42 and webs 43 of the flywheel, for example the flywheel 25". Figure 14 , is directed. Such inspection holes 61 are typically used to check the thickness of the brake pads. This embodiment of a sensor holder 60 can therefore be used with such pole wheels where the recesses 42 and webs 43 lie on a circle whose diameter is smaller than the outer diameter of the brake carrier plate 34.

Claims

1. Trailer stabilisation system for a vehicle trailer, comprising - a rotational speed detection device for determining the rotational speed of at least one trailer wheel (53), wherein the rotational speed detection device comprises a pole wheel (25, 25', 25"), which is connected to a brake hub (24) or brake drum of a wheel brake of the vehicle trailer, and at least one rotational speed sensor (51) that interacts with the pole wheel (25, 25', 25"), - an electronic controller (44), which is connected to the rotational speed detection device, for controlling at least one brake actuator (19) to produce a brake force and to brake the at least one trailer wheel (53) by means of the wheel brake as a function of the detected rotational speed of the trailer wheel (53), characterised in that the rotational speed sensor (51) is attached to a sensor holder (56), which is attached to a stub axle (5) of a trailer axle, said stub axle (5) serving to mount the brake hub (24) or brake drum, and in that the pole wheel has a substantially L-shaped cross-section, wherein a plurality of depressions (42) are arranged in a vertical limb (41) of the pole wheel (25), wherein connecting bars (43) are located between the depressions (42), wherein the depressions (42) and connecting bars (43) are arranged relative to the rotational speed sensor such that they are led past the rotational speed sensor and cause changes in the magnetic field there.

2. Trailer stabilisation system according to claim 1, characterised in that the sensor holder (56) has a clamping device in the form of a clamp (57) for encompassing the stub axle (5) and for retaining the sensor holder (56) on the stub axle (5).

3. Trailer stabilisation system according to claim 2, characterised in that one half (57b) of the clamp (57) is integrally connected to an arm (59), which extends from the clamp (57) to the pole wheel (25, 25', 25").

4. Trailer stabilisation system for a vehicle trailer, comprising - a rotational speed detection device for determining the rotational speed of at least one trailer wheel (53), wherein the rotational speed detection device comprises a pole wheel (25, 25', 25"), which is connected a brake hub (24) or brake drum of a wheel brake of the vehicle trailer, and at least one rotational speed sensor that interacts with the pole wheel (25, 25', 25"), - an electronic controller (44), which is connected to the rotational speed detection device, for controlling at least one brake actuator (19) to produce a brake force and to brake the at least one trailer wheel (53) by means of the wheel brake as a function of the detected rotational speed of the trailer wheel (53), characterised in that the rotational speed sensor (51) is attached to a sensor holder (54) which is attached to a cable insertion fitting (35) of a brake carrier plate (34), and in that the pole wheel has a substantially L-shaped cross-section, wherein a plurality of depressions (42) are arranged in a vertical limb (41) of the pole wheel (25), wherein connecting bars (43) are located between the depressions (42), wherein the depressions (42) and connecting bars (43) are arranged relative to the rotational speed sensor such that they are led past the rotational speed sensor and cause changes in the magnetic field there.

5. Trailer stabilisation system according to claim 4, characterised in that the cable insertion fitting (35) has a first holding shell (35a), which is attached to the brake carrier plate (34), and a second holding shell (35b), which is detachably connected to the first holding shell (35a), wherein the sensor holder (54) is attached to the detachable second holding shell (35b).

6. Trailer stabilisation system for a vehicle trailer, comprising - a rotational speed detecting device for determining the rotational speed of at least one trailer wheel (53), wherein the rotational speed detection device comprises a pole wheel (25, 25', 25"), which is connected to the brake hub (24) or brake drum of a wheel brake of the vehicle trailer, and at least one rotational speed sensor (51) that interacts with the pole wheel (25, 25', 25"), - an electronic controller (44), which connected to the rotational speed detection device, for controlling at least one brake actuator (19) to produce a brake force and to brake the at least one trailer wheel (53) by means of the wheel brake as a function of the detected rotational speed of the trailer wheel (53), characterised in that the rotational speed sensor (51) is attached to a sensor holder (60), which is attached to a brake carrier plate (34) in the region of a viewing hole (61), provided in the brake carrier plate (34), in such a way that the rotational speed sensor (51) is directed through the viewing hole (61) towards the pole wheel (25, 25', 25"), and in that the pole wheel has a substantially L-shaped cross-section, wherein a plurality of depressions (42) are arranged in a vertical limb (41) of the pole wheel (25), wherein connecting bars (43) are located between the depressions (42), wherein the depressions (42) and connecting bars (43) are arranged relative to the rotational speed sensor such that they are led past the rotational speed sensor and cause changes in the magnetic field there.