Wheel bearing unit for supporting a vehicle wheel with a measuring device and method for mounting a measuring device

Abstract

The invention relates to a wheel bearing unit for supporting a vehicle wheel, having a wheel hub and a rolling bearing unit, wherein a rolling body assembly comprises at least two rows of rolling bodies, which are arranged between an outer ring (1) and the wheel hub or an inner ring, and a measuring device (2) having at least one measuring point (5) is arranged on the outer ring (1), wherein the measuring device (2) is connected to the outer ring (1) in an interference fit, in particular by means of a press fit or a heat-shrink fit.

Description

Technical Field

[0001] This invention relates to a wheel bearing unit for supporting a vehicle wheel, comprising a wheel hub and a rolling bearing unit, wherein the rolling element assembly includes at least two rows of rolling elements disposed between an outer ring and the wheel hub or an inner ring, and a measuring device having at least one measuring point is provided on the outer ring. The invention also relates to a method for installing the measuring device. Background Technology

[0002] Currently, various autonomous driving systems are being developed for commercial vehicles such as trucks, trailers, and buses. Controlling these systems, especially so-called steer-by-wire systems, primarily utilizes remote sensors such as radar, lasers, ultrasonic sensors, and cameras. Against this backdrop, the demand for additional sensor data is expected to increase further in the future. Wheel forces are receiving particular attention, but there is also a desire to measure vibrations and temperature.

[0003] Especially in the field of autonomous driving, it is necessary to determine the forces acting on the wheel bearings as close as possible and as accurately as possible at the vehicle's wheels.

[0004] In existing solutions, the necessary measuring device is applied directly to the wheel bearing via coating or bonding. However, the resulting cost increase reduces market acceptance. An alternative is to fix the measuring device to the wheel bearing with screws. In this case, the bearing structure is weakened at these locations, leading to predictable material fatigue at these fixing points.

[0005] Therefore, existing systems, due to their layout and construction, either cannot provide very accurate data or are extremely expensive.

[0006] Document DE 10 2018 111 841 A1 describes a wheel hub for supporting a vehicle wheel on an axle, wherein a measuring ring is provided for measuring the force at the wheel bearing. The measuring ring is axially mounted in front of an inner ring and has at least one measuring structure for measuring tension and / or compression. Summary of the Invention

[0007] The objective of this invention is to provide a wheel bearing unit that enables the measurement of wheel forces at the wheel with the greatest possible accuracy and at the lowest cost.

[0008] The present invention achieves this task through a wheel bearing unit having the features of claim 1 and a method for mounting the wheel bearing unit according to claim 9. Preferred embodiments of the invention are given by the dependent claims and the following description, and these features may constitute an aspect of the invention individually or in combination.

[0009] According to the present invention, a wheel bearing unit for supporting a vehicle wheel has a hub and a rolling bearing unit, wherein the rolling element assembly includes at least two rows of rolling elements disposed between an outer ring and the hub or an inner ring. A measuring device with at least one measuring point is provided on the outer ring, wherein the measuring device is connected to the outer ring by an interference fit, particularly by a press fit or a heat shrink fit.

[0010] This provides a cost-effective solution that ensures accurate measurement data. Preferably, the measuring device is connected to the outer ring of the wheel bearing in a manner that prevents it from being detached from the outer ring without causing damage. The measuring device is preferably mounted on the outer cylindrical surface of the outer ring.

[0011] According to one embodiment, the measuring device is configured as an annular disk and has at least two radially protruding support surfaces for the outer ring. Thus, the measuring device does not adhere to the outer ring through its entire inner surface, but only through the surfaces of the radially protruding support surfaces.

[0012] Preferably, the measuring device is divided into zones, particularly three to four zones. This means that the measuring device has separable areas in the circumferential direction, in which measuring points can be arranged, for example.

[0013] Preferably, the measuring device has multiple measuring points. These measuring points can be arranged circumferentially along the annular disk of the measuring device at uniform or non-uniform intervals. The measuring points can be a coating, such as a Sensortect coating. In this thin-film sensing technology, the strain gauge functions as a coating directly applied to the corresponding component. This coating is applied at least locally to the outer cylindrical surface of the measuring device.

[0014] Alternatively, the measurement point can be a strain gauge (DMS), applied to the outer cylindrical surface of the measuring device. Strain gauges are measuring devices used to detect tensile and compressive deformation. They change their resistance even under minute deformation and are used as tensile sensors. They are typically attached to the component that undergoes minute deformation under load using a special adhesive. This deformation (strain) then causes a change in the resistance of the DMS. These methods ensure very accurate measurements of the dominant force at wheel bearings.

[0015] Particularly preferably, the measuring device has a sealing layer. The sealing layer is applied to the measuring device, primarily to protect the measuring point.

[0016] According to one embodiment, the measuring device has another measuring point for measuring temperature and / or acceleration.

[0017] The present invention also relates to a method for mounting a measuring device onto a wheel bearing unit, wherein the first step is to process, in particular to finish-machine, the cylindrical surface of the outer ring; the subsequent step is to orient the measuring device in position and connect it to the outer ring with an interference fit; and the following step is to seal the measuring points of the measuring device.

[0018] In manufacturing the measuring device, the annular surface of the disc is first exposed. After the measuring point is applied, the exposed annular surface is completely sealed using a substrate, thus forming a fully covered annular surface. This serves to protect the measuring point. The measuring device is also connected to an electronic device that converts the measured signal into a typical force value for the vehicle and inputs it into the vehicle's ECU. Attached Figure Description

[0019] The invention will now be described by way of example with reference to the accompanying drawings and based on preferred embodiments, wherein the features shown below may constitute an aspect of the invention individually or in combination. As shown: Figure 1. Three-dimensional view of the outer ring with measuring device according to the present invention. Figure 2. Cross-sectional view of the measuring device according to the present invention. Figure 3. Three-dimensional view of the outer ring with the sealed measuring device. Figure 4 According to Figure 3 Cross-sectional view of the outer ring Detailed Implementation

[0020] Figure 1 A three-dimensional view of the outer ring (1) of the wheel bearing unit is shown. The outer ring (1) has a fixing point (1a) for fixing the wheel bearing to the wheel bracket. The outer ring (1) also has a substantially cylindrical outer cylindrical surface on which a measuring device (2) is disposed. The measuring device (2) is substantially constructed as an annular disk. A leg (2a) extending circumferentially and projecting radially outward is formed at each of the two end faces of the measuring device (2). The measuring device (2) has a substantially cylindrical surface (2b) between the two radial legs (2a) on which measuring points (5) can be applied. The annular disk of the measuring device (2) is provided with at least one, preferably multiple, measuring points (5). The measuring points (5) may be a coating, such as a Sensotect coating, or a strain gauge. The measuring points (5) are distributed circumferentially on the measuring device (2). Figure 1 It can also be seen that the cylindrical surface (2b) of the measuring device (2) is divided into sections (4) along its circumference. Particularly preferred is that the surface (2b) has at least three sections. In particular, a measuring point (5) is applied to each section (4). Figure 2 From Figure 1The outer ring (1) with measuring device (2) is shown in cross-section. It can be seen that the measuring device (2) is applied to the outer cylindrical surface of the outer ring (1) in an interference fit manner.

[0021] Figure 3 The outer ring (1) and measuring device (2) are shown, wherein a sealing layer (7) for measuring point (5) has been formed. The sealing layer (7) for measuring point (5) is used to protect it, thereby improving the life of the wheel bearing. The sealing layer (7) may have additional functions, such as guidance (7a), especially cable guidance. The sealing layer (7) preferably ends flush with the radial leg (2a) of the measuring device (2).

[0022] Figure 4 It shows according to Figure 3 A cross-sectional view of the outer ring (1). The measuring device (2) has a support surface (3), which forms an annular contact surface with the outer ring (1). Through the support surface (3), the small unevenness on the cylindrical surface of the outer ring (1) can be ignored. This ensures the reliable fixation of the measuring device (2).

[0023] Explanation of reference numerals in the attached figures 1 Outer ring 1a Fixed point 2. Measuring device 2a Radial leg 2b Cylindrical surface 3 Support surface 4 partitions 5 Measurement points 6. Another measurement point 7. Sealing layer 7a Guidance Axial direction R radial direction

Claims

1. A wheel bearing unit for supporting a vehicle wheel, comprising a hub and a rolling bearing unit, wherein the rolling element assembly includes at least two rows of rolling elements disposed between an outer ring (1) and the hub or an inner ring, wherein a measuring device (2) is disposed on the outer ring (1), the measuring device (2) having at least one measuring point (5), characterized in that, The measuring device (2) is connected to the outer ring (1) by an interference fit, particularly by a press fit or a heat shrink fit.

2. The wheel bearing unit according to claim 1, wherein, The measuring device (2) is configured as an annular disk and has at least two radially protruding support surfaces (3) for the outer ring (1).

3. The wheel bearing unit according to claim 1 or 2, wherein, The measuring device (2) is divided into sections (4), specifically three sections (4).

4. The wheel bearing unit according to any one of the preceding claims, wherein, The measuring device (2) has multiple measuring points (5).

5. The wheel bearing unit according to any one of the preceding claims, wherein, The at least one measurement point (5) is formed by a coating, particularly a Sensotect coating.

6. The wheel bearing unit according to any one of the preceding claims, wherein, The at least one measurement point (5) is formed by a strain gauge (DMS).

7. The wheel bearing unit according to any one of the preceding claims, wherein, The measuring device (2) has a sealing layer (7).

8. The wheel bearing unit according to any one of claims 5 to 7, wherein, The measuring device (2) has another measuring point (6) for measuring temperature or acceleration.

9. A method for mounting a measuring device (2) onto a wheel bearing unit according to any one of the preceding claims, comprising: The first step is to process the cylindrical surface of the outer ring (1), especially by precision machining; The subsequent step is to orient the measuring device (2) according to its position and connect it to the outer ring (1) in an interference fit manner; And subsequent steps, sealing the measurement point (5).

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