Wheel suspension, elastically deformable component and motor vehicle

Abstract

A wheel suspension for a motor vehicle is proposed, comprising a non-load-bearing, elastically deformable component which is connected at a first end to a first portion of the wheel suspension that follows a suspension movement of the wheel, and which is connected at a second end to a second portion of the wheel suspension that does not follow a suspension movement of the wheel, wherein the elastically deformable component has a sensor element that is designed to detect a deformation of the elastically deformable component. This makes it possible to determine the ride height of a wheel of the motor vehicle in a simple manner, for example using a strain gauge. The measuring device does not have to be integrated into a load-bearing component of the wheel suspension and does not require any relative movement of several components to one another.

Description

[0001] The invention relates to a wheel suspension with a suspension system for at least one wheel of a motor vehicle, an elastically deformable component and a motor vehicle.

[0002] In motor vehicles, data on the current suspension state of the vehicle's wheels is regularly recorded. This data can be used, for example, to control a brake, traction control, or to adapt the chassis characteristics. Such a suspension state is understood to be a difference in the position of the respective wheel in the vertical direction from a zero or neutral position. The suspension state that is measured does not necessarily have to be the direct change in position in the vertical direction, but can also be a value from which this change can be calculated. Accordingly, the suspension state can also be referred to as the height of the respective wheel or as the wheel height.

[0003] For the detection of wheel-selective ride heights, a sensor device is typically used. It consists of several parts, each of which moves relative to the other. This multi-part concept is complex and requires multiple assembly steps. Likewise, the relative movement of the individual parts is associated with wear, and the measuring device is exposed to environmental influences. Other known measuring devices require a special axle structure or an elastically deforming element as part of the chassis.

[0004] A known method for detecting wheel height consists of a multi-part structure in which the multiple components perform a rotational movement relative to each other. For example, DE 10 2017 211 396 A1 discloses measuring the rotations in a bearing point between chassis components to determine wheel heights.

[0005] DE 10 2013 002 342 A1 describes another method for determining wheel height within the context of a special axle concept with leaf springs, in which a sensor concept with strain gauges can be used. This utilizes the deformation of the leaf spring during a compression or rebound process, which can be detected via the strain gauge and converted into a wheel height reading.

[0006] From DE 10 2015 224 633 A1 it is known to detect an elastic deformation of a component in a chassis by the associated change in length of an optical fiber.

[0007] The known concepts have disadvantages. For example, they can usually only be used with a specific axle concept, for example, using leaf springs, or they require the presence of elastically deforming control arms in the wheel suspension. General applicability of the solution to other axle concepts is typically not given. Furthermore, a special axle structure is often required, which results in elastic deformation of a force-transmitting component. The measurement setup, which is frequently used in production vehicles, has the disadvantage that it consists of several individual components that must be assembled before the actual vehicle assembly. In addition, individual components are exposed to environmental influences, which can lead to increased wear or damage to the sensor structure.

[0008] It is therefore the object of the present invention to propose a wheel suspension which allows a reliable determination of the height of the wheel and whose concept can be easily transferred to various axle concepts.

[0009] The object is achieved according to the invention by a wheel suspension of the type mentioned at the outset, which has a non-load-bearing, elastically deformable component which is connected at a first end to a first part of the wheel suspension following a suspension movement of the wheel, and which is connected at a second end to a second part of the wheel suspension not following a suspension movement of the wheel or to the body of the motor vehicle, wherein the elastically deformable component has a sensor element which is designed to detect a deformation of the elastically deformable component.

[0010] The object is further achieved by an elastically deformable component for a wheel suspension having a suspension system for a wheel of a motor vehicle, wherein the elastically deformable component is designed as a non-load-bearing component which has a first end for connection to a first part of the wheel suspension following a suspension movement of the wheel, and a second end for connection to a second part of the wheel suspension not following a suspension movement of the wheel or for connection to the body of the motor vehicle, wherein the elastically deformable component has a sensor element which is configured to detect a deformation of the elastically deformable component. The object is likewise achieved by a motor vehicle with a wheel suspension according to the invention and / or an elastically deformable component according to the invention.

[0011] The second end of the elastically deformable component is fixed relative to the vehicle body and thus does not change its position even if the ride height of the respective wheel changes. The first end of the elastically deformable component, on the other hand, is connected to the wheel or a part of the wheel suspension in such a way that a change in the ride height of the wheel changes the position of the first end of the elastically deformable component relative to the second end of the elastically deformable component. According to the invention, this change in the positions of the two ends of the elastically deformable component relative to one another is to be detected and used to determine the ride height of the wheel. The connections can be made using screws, rivets, bolts, clips, or other suitable connecting means. An adhesive connection or other form-fitting, force-fitting, or material-locking connection technology can also be used.

[0012] A suspension system for a wheel is understood in particular to be a combination of at least one spring element and one damper element. The wheel suspension can, in particular, be an independent wheel suspension. However, the invention can also be implemented within the framework of a twist-beam axle or a rigid axle. Furthermore, as is common in the prior art, the wheel suspension can, for example, comprise wishbones and / or other link elements such as wishbones, spring links, semi-trailing arms, or trailing arms, one or more wheel carriers, the aforementioned suspension system, and, for example, a connection to a steering gear.

[0013] For the purposes of this description, a non-load-bearing component is understood to mean, in particular, a component through which a maximum of a non-significant portion of the forces acting between the wheel and the wheel suspension or the body or body of the vehicle are transmitted. The non-load-bearing component can thus be an additional component that is not necessary for connecting the wheel to the vehicle and exclusively performs tasks related to determining the wheel's ride height.

[0014] In the context of this description, a suspension movement can be understood, in particular, as a compression or rebound of the wheel. A suspension movement of the wheel corresponding to compression occurs, for example, when driving over a raised unevenness in the road surface or the ground. A suspension movement corresponding to rebound occurs, for example, when driving over a pothole. The suspension system's task is to maintain the best possible contact between the wheel and the ground.

[0015] In the context of this description, whether a part of the wheel suspension follows or does not follow a suspension movement is understood in particular to mean that the part of the wheel suspension moves or does not move relative to the body of the motor vehicle when the wheel executes a suspension movement. A part of the wheel suspension can be understood in particular as a dedicated component or a section or region of such a component.

[0016] The sensor element can therefore be used to determine information about the spring deflection of the corresponding wheel. The elastic deformation of the elastically deformable component, such as bending, can be detected by the sensor element. This sensor data can then be used to determine the degree of deformation of the elastically deformable component and thus the spring deflection state.

[0017] According to the invention, it was recognized that it offers advantages to separate the functions of the load-bearing components of the wheel suspension and the measuring system for determining the spring deflection or ride height of the respective wheel. At the same time, it was recognized that parts that move relative to one another, particularly those that perform translational or rotational movements, are susceptible to wear. Therefore, it can advantageously be provided to use a sensor element that is located in a dedicated measuring device for detecting ride height and is not embedded or applied in or to an existing axle component, as in the previous technical design known from the prior art.

[0018] In contrast to prior art solutions, the one-piece solution for detecting wheel-selective deflection eliminates the need for wear-prone relative movement between multiple components in the device for detecting deflection. Furthermore, unlike other known solutions, the solution according to the invention does not require at least one component of the chassis to undergo elastic deformation during wheel deflection, but rather implements this elastic deformation in the actual structure of the measuring device. Separating the functions between wheel deflection guidance and wheel ride height detection also enables retrofitting of the measuring device without affecting the wheel guidance.

[0019] According to the invention, it can advantageously be provided that the elastically deformable component is connected to the first part of the wheel suspension and the second part of the wheel suspension in such a way that a bending moment or other mechanical stress, for example torsion, stretching or compression, acts on the component during a spring compression movement of the wheel. The elastically deformable component is then bent during a spring compression or rebound movement of the wheel. Such a configuration can be achieved, for example, if the elastically deformable component forms an angle with the horizontal of, for example, 60° or less, 45° or less, or 20° or less. The angle can be regarded, for example, as the angle formed by an imaginary straight line running along the greatest extent of the elastically deformable component with the horizontal.It is thus possible and preferred that the elastically deformable component is aligned horizontally or approximately horizontally.

[0020] A practical embodiment provides for the elastically deformable component to be beam- or rod-shaped. In other words, the component can have a relatively large aspect ratio of, for example, more than 3:1, more than 5:1, or more than 10:1 between a length in the direction of greatest extent of the elastically deformable component and a length in a direction perpendicular to the direction of greatest extent. A beam- or rod-shaped design enables, in addition to a low weight of the measuring device, an easily detectable elastic deformation of the measuring device. If beam- or rod-shaped, the elastically deformable component can have the shape of a cuboid or a cylinder. It is also possible for the elastically deformable component to have a curved shape. The cross-section can be, for example, square, cylindrical, elliptical, polygonal, or rectangular.The elastically deformable element can, for example, have an arcuate or C-shaped configuration. Mounting the measuring device on a wishbone is preferred, as this results in a compact design and easily detectable elastic deformation.

[0021] According to an advantageous embodiment, the elastically deformable component has a plastic component. It is also possible for the elastically deformable component to be made entirely or almost entirely of plastic. This does not, of course, mean that the sensor element must also be made of plastic. In other words, a body of the elastically deformable component can be made partially, almost entirely, or entirely of plastic. The elastically deformable component can then consist of the body of the elastically deformable component and the sensor element. The elastically deformable component can also be made of a material other than plastic or using multiple materials to achieve the shape and other component properties, such as rigidity.The elastically deformable component can have a metal component or be made of a metal, such as steel. For example, the elastically deformable component can be manufactured by sputtering a strain gauge onto a spring steel.

[0022] According to a preferred embodiment, the sensor element is designed as a strain gauge. The electrical resistance of such a strain gauge varies depending on the strain state of the strain gauge. It is therefore a passive component that can be easily read. If the elastically deformable component is bent during a suspension movement of the wheel, this change in shape is also transferred to the strain gauge, which subsequently changes its electrical resistance compared to its resistance in the neutral position. The electrical resistance of the strain gauge can be measured, for example continuously, which then allows conclusions to be drawn about the suspension compression or the ride height of the wheel.

[0023] More than one strain gauge can be integrated into the elastically deformable component. For example, the elastically deformable element can have at least two or at least three sensor elements, such as strain gauges. These can then, for example, detect additional relative movements of the wheel or be provided for redundancy purposes.

[0024] The first part of the wheel suspension can be designed as a wishbone, a spring link, a trailing arm, a semi-trailing arm, a leaf spring, a wheel carrier, a stabilizer bar, a coil spring, a damper element, or as another element that moves relative to the body during compression. The wheel suspension according to the invention can therefore be integrated into almost any chassis concept. Since no load-bearing components are used to measure the wheel ride height, an elastically deformable component according to the invention can also be easily retrofitted. Corresponding control units, which evaluate the supplied sensor data and convert it into a wheel ride height, are generally already present in current motor vehicles.

[0025] A further development of the invention provides that the sensor element is enclosed by a casing portion of the elastically deformable component. In other words, it is possible for the sensor element to be integrated into the elastically deformable component. The elastically deformable component can have connection elements, for example electrical contacts, on an outer side for reading out the data supplied by the sensor element. The sensor element can be introduced into the elastically deformable component during its manufacture. For example, the sensor element can be overmolded in a plastic. The sensor element can be almost completely or completely embedded in the elastically deformable component. Contact points for reading out the data of the sensor element can be arranged on an outer side of the elastically deformable component.Such an elastically deformable component, in which the sensor element is integrated as described, is easy to manufacture, and the sensor element can thus be reliably protected from environmental influences and mechanical damage.

[0026] According to a preferred embodiment, the elastically deformable component has a stiffness such that the spring rate of the wheel suspension, which indicates the relationship between the vertical force on the wheel and the wheel's spring travel, is not significantly altered by the attachment of the elastically deformable component. The spring rate can change, for example, by less than 5% or less than 1% before and after the attachment of the elastically deformable component. The same applies to the stabilization rate. The stabilization rate describes the relationship between the change in force of a first wheel on an axle and a change in travel of a second wheel on an axle.

[0027] Embodiments of the invention are explained in more detail with reference to the drawings and the following description. It shows: Fig. 1: a schematic representation of a section of a motor vehicle with a wheel suspension according to the invention.

[0028] Fig. 1 shows a schematic representation of a section of a motor vehicle with a wheel suspension 2 according to the invention. The wheel suspension 2 supports the wheel 4. The motor vehicle is in contact with the ground 6 via the wheel 4 and the other wheels (not shown). The wheel suspension 2 comprises several components, in particular the control arm 8 designed as a wishbone, the spring-damper system 10 and the wheel hub 12. The wheel suspension 2 connects the wheel 4 to the body 14, wherein an area that is arranged in the immediate vicinity of the control arm 8, for example, is also counted as belonging to the wheel suspension 2 in the present case.

[0029] The elastically deformable component 16 also connects the body 14 to the wheel suspension 2. However, the elastically deformable component 16 is designed as a non-load-bearing component, so that no significant forces are transmitted between the body 14 and the wheel suspension 2 via the elastically deformable component 16. The elastically deformable component 16 is beam-shaped and is connected to the wheel suspension 2 at a first end 18 by means of a first screw 22. The second end 20 of the elastically deformable component 16, opposite the first end 18, is connected to the body 14 by means of a second screw 24.

[0030] When the wheel 4 travels over an uneven road surface, the wheel suspension 2 enables it to perform a vertical movement relative to the body 14, indicated by the double arrow 26. In other words, in this situation, the position of the body 14 remains unchanged in the vertical direction, while the wheel 4 changes its position in the vertical direction. A first portion 36 of the wheel suspension in the form of a first region of the control arm 8, to which the first end 18 of the elastically deformable component 16 is connected, also performs a vertical movement relative to the body 14 in the same direction, indicated by the double arrow 28. Since the first end 18 of the elastically deformable component 16 is rigidly connected to an element of the wheel suspension, in this case to the control arm 8, the first end 18 also follows this vertical movement.At the same time, the second end 20 of the elastically deformable component 16 is rigidly connected to the body 14, which does not perform any vertical movement. Accordingly, the second end 20 of the elastically deformable component 16 also remains unchanged with regard to its vertical position.

[0031] The movement of the first end 18 of the elastically deformable component 16 causes the elastically deformable component 16 to bend. A sensor element 30 in the form of a strain gauge is embedded in the elastically deformable component 16. The strain gauge 30 extends along a longitudinal direction of the elastically deformable component 16. The strain gauge is also bent or stretched during the suspension movement of the wheel 4, so that its electrical resistance changes compared to its resistance in the neutral position of the elastically deformable component 16. A signal can be tapped and evaluated via lines 32, which are also embedded in the elastically deformable component 16, and via the connection points 34. From this signal, the ride height of the wheel 4 can be calculated and further used. List of reference symbols 2 wheel suspension 4 wheel 6 Underground 8 handlebars 10 spring-damper system 12 Wheel hub 14 Body 16 elastically deformable component 18 first end 20 second end 22 first screw 24 second screw 26 vertical movement 28 vertical movement 30 sensor element 32 lines 34 connection points 36 first connection area 38 second connection area QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 211 396 A1

[0004] DE 10 2013 002 342 A1

[0005] DE 10 2015 224 633 A1

[0006]

Claims

Wheel suspension (2) with a suspension system for at least one wheel (4) of a motor vehicle, characterized by a non-load-bearing, elastically deformable component (16) which is connected by a first end (18) to a first portion (36) of the wheel suspension (4) that follows a suspension movement of the wheel (4), and which is connected by a second end (20) to a second portion (38) of the wheel suspension (4) that does not follow a suspension movement of the wheel (4) or to the body of the motor vehicle, wherein the elastically deformable component (16) has a sensor element (30) that is designed to detect a deformation of the elastically deformable component (16). Wheel suspension (2) according to claim 1, characterized in that the elastically deformable component (16) is connected to the first part (36) of the wheel suspension (4) and the second part (38) of the wheel suspension (4) in such a way that a bending moment or other mechanical stress acts on the elastically deformable component (16) during a compression movement of the wheel (4). Wheel suspension (2) according to one of the preceding claims, characterized in that the elastically deformable component (16) is designed in the shape of a beam or rod. Wheel suspension (2) according to one of the preceding claims, characterized in that the elastically deformable component (16) has a plastic component. Wheel suspension (2) according to one of the preceding claims, characterized in that the sensor element (30) is designed as a strain gauge. Wheel suspension (2) according to one of the preceding claims, characterized in that the first part (36) of the wheel suspension is designed as a wishbone, as a spring link, as a coil spring, as a longitudinal link, as a semi-trailing link, as a leaf spring, as a wheel carrier, as a stabilizer, as a damper element or as a further element which moves relative to the body during compression. Wheel suspension (2) according to one of the preceding claims, characterized in that the sensor element (30) is enclosed by a casing portion of the elastically deformable component (16). Wheel suspension (2) according to one of the preceding claims, characterized in that the sensor element (30) is encapsulated by a plastic. An elastically deformable component (16) for a wheel suspension (2) comprising a suspension system for a wheel (4) of a motor vehicle, characterized in that the component (16) is designed as a non-load-bearing component (16) which has a first end (18) for connection to a first portion (36) of the wheel suspension (4) which follows a suspension movement of the wheel (4), and a second end (20) for connection to a second portion (38) of the wheel suspension (4) which does not follow a suspension movement of the wheel (4), wherein the elastically deformable component (16) has a sensor element (30) which is configured to detect a deformation of the elastically deformable component (16). Motor vehicle with a wheel suspension (2) according to one of claims 1 to 8 and / or with an elastically deformable component (16) according to claim 9.

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