Wheel bearing arrangement for a wheel of a two-wheeler and method for detecting the road surface condition of a subsoil

Abstract

Wheel bearing arrangement (10) for a wheel (18) of a two-wheeler, in particular a motorcycle, with at least one bearing (16) for rotatably mounting the wheel (18) on an axle (14) and an acceleration sensor (20) coupled to the bearing (16) for detecting acceleration in the vertical direction, wherein the bearing (16) has an inner ring fixed to the axle (14) in a rotationally fixed manner, wherein the acceleration sensor (20) is fixed to the inner ring in a movement-resistant manner, and wherein the acceleration sensor (20) has several sensor elements arranged one behind the other in the circumferential direction, and wherein an evaluation unit coupled to the acceleration sensor (20) is provided for assessing road surface condition depending on the signals detected by the acceleration sensor (20).

Description

[0001] The invention relates to a wheel bearing arrangement for a wheel of a two-wheeler, with the aid of which a wheel of the two-wheeler can be mounted, and a method for detecting a road surface condition of a substrate, with the aid of which a detected road surface condition can be taken into account in a driver assistance system.

[0002] From DE 10 2013 225 586 A1 it is known to derive road surface irregularities from the speed profile of speed sensors integrated in a brake or stability assistance system.

[0003] DE 10 2017 121 010 A1 describes a bearing arrangement for a wheel hub of a motor vehicle comprising a multi-row rolling bearing. The outer ring of the rolling bearing is non-rotatably connected to a wheel carrier, the wheel carrier having a sensor carrier with an ABS sensor element for detecting wheel speed and an acceleration sensor element for detecting running noise.

[0004] DE 39 30 517 A1 discloses a device for road-dependent chassis control of a vehicle with sensors that detect the dynamic driving condition. In each wheel area, a sensor is provided that detects the damping force, the relative distance (suspension travel) between the wheel and a body section of the vehicle located in the wheel area, and the vertical wheel acceleration.

[0005] DE 197 03 832 A1 describes a rolling bearing, in particular a wheel bearing for motor vehicles, with sensors for detecting wheel speed or wheel acceleration and drive and / or braking accelerations. At least one sensor is mounted on a rotating part of the bearing and at least one sensor is mounted on a stationary part of the bearing.

[0006] DE 100 41 093 A1 discloses a sensor arrangement in a rolling bearing and a method for evaluating the output signal of the sensor arrangement. Two sensors are mounted on the stationary bearing shell, offset from each other by half the angular distance between the rolling elements in the direction of rotation.

[0007] There is a constant need to be able to detect road surface irregularities cost-effectively and reliably.

[0008] The purpose of the invention is to demonstrate measures that enable cost-effective and reliable detection of road surface irregularities for a wheel of a two-wheeler.

[0009] The problem is solved according to the invention by a wheel bearing arrangement with the features of claim 1 and a method with the features of claim 8. Preferred embodiments of the invention are specified in the dependent claims and the following description, each of which can individually or in combination represent an aspect of the invention.

[0010] One aspect of the invention relates to a wheel bearing arrangement for a wheel of a two-wheeler, in particular a motorcycle, with at least one bearing for rotatably mounting the wheel on an axle and an acceleration sensor coupled to the bearing for detecting acceleration in the vertical direction.

[0011] The acceleration sensor allows for the direct measurement of wheel movement caused by road surface irregularities. This avoids the limitations of indirect measurement methods that can compromise accuracy. Furthermore, measuring the vertical acceleration component is a significantly more reliable indicator of road surface irregularities than measuring wheel rotational speed fluctuations, which can be caused by other factors such as a torque surge from an electric motor engaged during boost mode.Because the accelerometer acts on the bearing and is not located inside the wheel, acceleration forces can be reliably detected even when the motorcycle is at an extreme lean angle, for example, during high-speed cornering, resulting in significantly different wheel deformations that could otherwise interfere with the detectable sensor signal of an accelerometer located inside the tire. Forces absorbed by the wheel act on the bearing both when traveling straight ahead and when leaning; these forces can be detected and subsequently evaluated by the accelerometer. For this purpose, the accelerometer can be integrated cost-effectively, essentially without requiring additional installation space, directly against the bearing being monitored, within the existing space provided by a hub or similar component.The acceleration sensor acting on the bearing allows road surface irregularities to be detected cost-effectively and reliably, even when the two-wheeler is at an extreme angle.

[0012] According to the invention, the bearing has an inner ring that is fixed to the axle in a rotationally fixed manner, and the accelerometer is fixed to the inner ring in a movement-resistant manner. The axle, which is particularly stationary, can be mounted in a wheel fork of the two-wheeler to rotatably support the wheel, for example, a front wheel or a rear wheel, with the aid of the at least one bearing. By attaching the accelerometer to the inner ring, the accelerometer can monitor a precisely defined circumferential angular range of the bearing. The accelerometer is particularly preferably configured to detect elastic deformation of the inner ring as a result of the applied acceleration forces. For this purpose, the accelerometer can, for example, include at least one cost-effective strain gauge.This makes it possible to detect road surface irregularities via the deformation behavior of the wheel as it rolls on the surface, which leads to a corresponding load on the inner ring of the bearing. While on a level surface the contact pressure of the wheel is essentially constant during rolling and no significant acceleration forces occur in the vertical direction that could elastically deform the inner ring, on an uneven surface different contact pressures occur, which can be determined by signal peaks in the detected vertical acceleration forces.

[0013] Preferably, the bearing is designed as a rolling bearing, in particular a ball bearing, wherein the bearing has an inner ring that can be tilted to a limited extent relative to an outer ring. Within the limits of the inner ring's tilting range, a central axis of the inner ring can thus be oriented essentially horizontally even when the two-wheeler is tilted, so that a correspondingly large proportion of the acceleration forces acting on the wheel act vertically on the inner ring. This allows the acceleration sensor to detect a sufficiently strong signal even when the bicycle is tilted.

[0014] According to the invention, the accelerometer has several sensor elements arranged one behind the other in the circumferential direction. This improves the resolution of the accelerometer in the circumferential direction. Furthermore, the circumferential angle range to be monitored can be defined more precisely.

[0015] In particular, the accelerometer's measuring range extends over a circumferential angle range Δα, where the circumferential angle range Δα is larger than the deformation angle range Δβ of the wheel deformed on a surface. The circumferential angle range is, in particular, slightly larger than the deformation angle range, for example, by 1% to 5% or up to 10%. This allows the accelerometer to scan the entire circumferential angle range within which the wheel rolls, resulting in elastic deformation on the surface. Influences on the measurement signal outside the deformation angle range, not caused by unevenness in the road surface, can thus be largely minimized.

[0016] According to the invention, an evaluation unit coupled to the acceleration sensor is provided for assessing road surface condition based on the signals detected by the acceleration sensor. The evaluation unit is preferably configured to determine, from the detected signals of the acceleration sensor, the beginning and end of deformation of the wheel on a surface during rolling, and to assess the road surface condition from the detected signals of the acceleration sensor between the beginning and end of deformation. Road surface condition can thus be detected with high accuracy and reliability and, in particular, taken into account in a driver assistance system connected to the evaluation unit.

[0017] The invention further relates to a two-wheeler, in particular a motorcycle, with a front wheel mounted in a wheel bearing arrangement as described above, and / or a rear wheel mounted in a wheel bearing arrangement as described above, and a driving assistance system, in particular a braking and / or stability assistance system, coupled to the acceleration sensor of the wheel bearing arrangement, for automatically adapting driving characteristics to the road surface. The acceleration sensor acting on the bearing allows road surface irregularities to be detected cost-effectively and reliably even at extreme lean angles of the two-wheeler. The road surface can thus be detected with high accuracy and reliability and taken into account in the driving assistance system connected to the evaluation unit.

[0018] One aspect of the invention relates to a method for detecting the road surface condition of a subsurface, in which the course of a component of acceleration forces acting in a vertical direction on a bearing for supporting a wheel of a two-wheeled vehicle, in particular a motorcycle, is detected and evaluated, wherein the bearing is part of a wheel bearing arrangement according to the invention. This method utilizes the fact that even in any inclined position of the two-wheeled vehicle, the forces on the wheel are supported via the at least one bearing, and that the acceleration forces caused by road surface irregularities can be reliably detected in the vertical direction at this point.

[0019] In particular, only the acceleration forces during a point on the wheel's rolling motion along a surface are considered for detecting the road surface condition. This essentially means that only a circumferential angle range is taken into account, within which the wheel rolls and the associated elastic deformation occurs on the surface. Influences on the measurement signal that are not caused by road surface irregularities and that occur outside this deformation circumferential angle range can thus be largely minimized.

[0020] The acceleration sensor acting on the bearing allows road surface irregularities to be detected cost-effectively and reliably, even when the two-wheeler is at an extreme angle.

[0021] The invention is explained below by way of example with reference to the accompanying drawings and preferred embodiments, wherein the features shown below can represent an aspect of the invention, either individually or in combination. The drawings show: Fig. 1: a schematic sectional view of a wheel bearing arrangement, Fig. 2: A schematic side view of a part of a two-wheeler showing the wheel bearing arrangement made of Fig. 1 and Fig. 3: a comparison of differently measured acceleration signals at different lean angles of the two-wheeler Fig. 2.

[0022] The in Fig. The wheel bearing arrangement 10 shown in Figure 1 for a two-wheeler, in particular one driven by a motor and / or an electric motor, has a rotatable or stationary axle 14 attached to a wheel fork 12, on which a wheel 18 is rotatably mounted via, for example, two bearings 16, in particular designed as ball bearings. An acceleration sensor 20 is coupled to at least one bearing 16, preferably to both bearings 16. The acceleration sensor 20 has several strain gauges arranged one behind the other in the circumferential direction within a limited circumferential angular range, which preferably detect mechanical stresses in an inner ring of the bearing 16 caused by vertical acceleration forces.The vertical acceleration forces occurring during the rolling of the wheel 18 on a surface 22 are usually caused by road surface irregularities, so that a measurement signal 24 from the acceleration sensor 20 can be evaluated in an evaluation unit not shown to assess the road surface condition in order to be adequately taken into account in a driver assistance system.

[0023] As in Fig. As shown in Figure 2, the acceleration sensor 20 can detect the acceleration forces within a measurement circumferential angle range Δα, which with some certainty completely covers a deformation circumferential angle range Δβ in which the wheel 18 is elastically deformed on the surface 22. Irregular signals occur before a deformation start 26, also referred to as the "trample point," where a point on the circumference of the wheel 18 contacts the surface 22, and after a deformation end 28, also referred to as the "kick point," where the point on the circumference of the wheel 18 lifts off the surface 22. Between the deformation start 26 and the deformation end 28, each of which can be identified by a clearly detectable jump in the measurement signal 24, a signal is generated that depends essentially only on the road surface properties of the surface 22.

[0024] As in Fig.As shown in Figure 3, the measurement signal 24 tapped at the bearing 16 is essentially the same at different inclination positions of the wheel 18. However, an accelerometer located centrally within the tire of the wheel 18 would, with an increasing inclination of the wheel 18, arrive further and further outside the area of ​​the wheel 18 deformed by the ground 22, so that a comparison signal 30 detected by this accelerometer becomes weaker and more difficult to interpret. In comparison to an accelerometer located in the tire of the wheel 18, the accelerometer 20 acting at the bearing 16 can generate a significantly more precise and reliable measurement signal 24. List of reference symbols 10 Wheel bearing arrangement 12 Wheel fork 14 axle 16 warehouses 18-inch wheel 20 Accelerometer 22 Underground 24 Measurement signal 26. Deformation begins 28 Deformation end 30 Comparison signal Δα Measuring circumference angle range Δβ Deformation circumferential angle range

Claims

[1] Wheel bearing arrangement (10) for a wheel (18) of a two-wheeler, in particular a motorcycle, with at least one bearing (16) for the rotatable mounting of the wheel (18) on an axle (14) and an acceleration sensor (20) coupled to the bearing (16) for detecting an acceleration in the vertical direction, wherein the bearing (16) has an inner ring fastened to the axle (14) in a rotationally fixed manner, wherein the acceleration sensor (20) is fastened to the inner ring in a movement-proof manner and wherein the acceleration sensor (20) has a plurality of sensor elements arranged one behind the other in the circumferential direction, and wherein an evaluation unit coupled to the acceleration sensor (20) is provided for assessing the condition of the road surface as a function of the signals detected by the acceleration sensor (20). [2] Wheel bearing arrangement (10) according to claim 1, wherein the bearing (16) is designed as a rolling bearing, wherein the bearing (16) has an inner ring which can be tilted to a limited extent relative to an outer ring. [3] Wheel bearing arrangement (10) according to claim 2, wherein the rolling bearing is designed as a ball bearing. [4] Wheel bearing arrangement according to one of claims 1 to 3, wherein a measuring range of the acceleration sensor (20) extends over a measuring circumferential angle range Δα, wherein the measuring circumferential angle range Δα is greater than a deformation circumferential angle range Δβ of the wheel (18) deformed on a ground (22). [5] Wheel bearing arrangement (10) according to one of claims 1 to 4, wherein the evaluation unit is designed to determine a start (26) of deformation of the wheel (18) on a ground (22) during rolling and a deformation end (28) of the wheel (18) on the ground (22) from the detected signals of the acceleration sensor (20) and to assess the road surface condition between the start (26) of deformation of the wheel (18) and the deformation end (28) of the wheel (18) from the detected signals of the acceleration sensor (20). [6] Two-wheeler, in particular motorcycle, with a front wheel mounted with a wheel bearing arrangement (10) according to one of claims 1 to 5 and / or a rear wheel mounted with a wheel bearing arrangement (10) according to one of claims 1 to 5 and a driver assistance system coupled to the acceleration sensor (20) of the wheel bearing arrangement (10) for automatically adapting driving characteristics to a road surface condition of a ground (22). [7] Two-wheeler according to claim 6, wherein the driving assistance system is a braking and / or stability assistance system. [8] Method for detecting the condition of a road surface (22), in which a profile of a component of acceleration forces acting in the vertical direction on a bearing (16) for supporting a wheel (18) of a two-wheeler, in particular a motorcycle, is detected and evaluated, wherein the bearing (16) is part of a wheel bearing arrangement (10) according to one of claims 1 to 5. [9] Method according to claim 8, in which only one course of the acceleration forces during a point of the wheel (18) rolling on the ground (22) is taken into account for detecting the road surface condition.

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