Air guidance system for a motor vehicle, in particular for a passenger car, as well as motor vehicles

Abstract

Air guidance device for a motor vehicle, comprising at least one wheel (14) of the motor vehicle rotatable about a wheel axis and having a rim (18) with an inner diameter, and comprising an air guidance element (24) associated with the wheel (14), which has an air guidance surface (26) for guiding air flowing towards the air guidance surface (26) when the motor vehicle is in motion, wherein the air guidance surface (26) extends in a plane perpendicular to the wheel axis, characterized in that the air guidance surface (26) directly adjoins a lower region (B) of an inner flank (28) of the rim (18) in the transverse direction of the vehicle and / or upwards in the vertical direction of the vehicle, and extends in the vertical direction over less than half of the inner diameter, and that the air guidance element (24) has at least one through-opening (36) penetrating the air guidance surface (26).and that the passage opening (36) is associated with a closing element (38) which is movable relative to the air guide element (24) between at least one closed position closing at least a partial area of ​​the passage opening (36) and at least one open position (O) releasing the partial area.

Description

[0001] The invention relates to an air guidance device for a motor vehicle according to the preamble of claim 1. Furthermore, the invention relates to a motor vehicle with at least one such air guidance device.

[0002] German patent application DE 10 2013 108 762 A1 discloses a motor vehicle with a wheel arch and a cover arranged in the area of ​​the wheel arch and projecting into the wheel arch to reduce the flow of air into the wheel arch when the vehicle is in motion. The cover is pivotable about a longitudinal axis of the vehicle and connected to an underbody panel of the vehicle on the side of the underbody panel facing the wheel arch.

[0003] US patent 2020 / 0014982A1 describes a disc-shaped cover for a rim of a motor vehicle wheel, which is arranged on the outside of the rim and essentially completely covers it.

[0004] The object of the present invention is to provide an air guidance device for a motor vehicle and a motor vehicle with such an air guidance device, so that a particularly advantageous aerodynamics of the motor vehicle can be achieved and excessive penetration of dirt and / or snow into the rim can be avoided.

[0005] This problem is solved according to the invention by an air guidance device having the features of claim 1 and by a motor vehicle having the features of claim 8. Advantageous embodiments with expedient further developments of the invention are the subject of the dependent claims.

[0006] A first aspect of the invention relates to an air guidance device for a motor vehicle, in particular for a passenger car. The air guidance device comprises at least one air guide element, which is associated with a wheel rotatable about a wheel axis, in particular relative to the body of the motor vehicle. The wheel comprises a rim which has an inner diameter. For example, a tire of the wheel is mounted on the rim. The wheel is a ground contact element by means of which the motor vehicle, also referred to as a motor vehicle, can be supported or is supported downwards against a ground in the vertical direction. Here, the wheel, in particular the tire, directly contacts the ground. The aforementioned body of the motor vehicle forms or delimits an interior of the motor vehicle, also referred to as a passenger compartment, in which persons such as the driver of the motor vehicle can be located. For example, the body is a self-supporting body.If the vehicle is driven along the ground while the vehicle is supported downwards on the ground via the wheel in the upward direction of the vehicle, the wheel rotates relative to the body around the wheel axis of rotation, and the wheel rolls along the ground.

[0007] The air guide element has an air guide surface by means of which air, which flows towards the air guide surface during a journey, in particular a forward journey, of the motor vehicle, is to be guided or is guided.

[0008] To achieve particularly advantageous aerodynamics for the vehicle—that is, to minimize air resistance and thus enable highly energy-efficient propulsion—the air guide surface is designed to extend in a plane perpendicular to the wheel's axis of rotation. If the wheel's axis of rotation runs, for example, in the transverse direction of the vehicle or parallel to it, the plane is defined by the vehicle's longitudinal direction (x-direction) and its vertical direction (z-direction), in which case it is also referred to as the xz-plane. It is conceivable that the wheel is an unsteered wheel, which cannot be steered. Furthermore, it is conceivable that the wheel is a steered wheel, which can be pivoted or steered, for example, to effect lane changes or changes of direction of the vehicle.Preferably, if the wheel is steerable, the air guide element or air guide surface is steerable with the wheel. Therefore, it is preferably provided that the air guide surface always extends in a plane perpendicular to the wheel's axis of rotation.

[0009] In particular, if the wheel is a non-steerable wheel, or if the wheel designed as a steerable wheel is set for straight-ahead driving of the vehicle and is therefore not turned, the plane coincides with the xz-plane, or the plane then runs parallel to the xz-plane.

[0010] According to the invention, the air guide surface is directly adjacent to a lower region of an inner flank of the rim in the transverse direction of the vehicle and / or upwards in the vertical direction of the vehicle. This means, in particular, that no other component is arranged between the air guide surface or air guide element and the inner flank. Furthermore, it is preferably provided that the air guide surface or air guide element does not touch the flank, i.e., is spaced from the flank, in particular such that a small air gap of, for example, a few millimeters is arranged between the air guide surface or air guide element and the flank. The air gap is, for example, bounded on one side directly by the flank and on the other side directly by the air guide element and is preferably at most ten millimeters wide, and more particularly at most five millimeters wide.In other words, it is intended that the air guide surface in the lower area of ​​the rim is arranged directly adjacent to the rim or the flank in the y-direction and / or in the z-direction.

[0011] Spacing the air guide element away from the rim such that an air gap is arranged between the air guide surface and the inner flank is advantageous to prevent the air guide element from rubbing against the rim when the rim rotates relative to the air guide element around the wheel's axis of rotation. However, it is also possible for the air guide surface or air guide element to be mounted on the rim, particularly in such a way that the air guide surface or air guide element is sealed against the rim, especially by means of at least one seal. This allows for particularly high aerodynamic efficiency.

[0012] Furthermore, according to the invention, the air guide surface extends in the vertical direction of the vehicle, particularly upwards from the sidewall, over less than half, and in particular less than one-third, of the inner diameter of the rim, also referred to as the inner rim diameter. This allows air to be guided particularly advantageously by means of the air guide surface during the vehicle's journey, thus reducing the vehicle's air resistance compared to conventional vehicles. Consequently, the vehicle can be driven with particular energy efficiency, enabling, for example, low fuel consumption or allowing it to be driven electrically over a particularly long range, especially purely.It was found that without the use of the air guide element, air can flow along the inner sidewall of the tire while the vehicle is in motion. This airflow can then strike the rim, potentially causing high air resistance. This undesirable airflow can now be prevented. In other words, the air guide prevents excessive airflow along the inner sidewall from entering the wheel or rim. The air guide element, also simply called a guide, and in particular its guide surface, can also prevent excessive ingress of snow and / or dirt into the rim.This prevents excessive corrosion of components such as axle components of the motor vehicle, as these components can be protected from excessive dirt and being thrown with snow and / or other objects by means of the air guide element.

[0013] Furthermore, the air guide element according to the invention has at least one through-opening that penetrates the air guide surface and thus allows air to flow through it. This enables, on the one hand, particularly advantageous aerodynamics of the motor vehicle. On the other hand, it enables sufficient brake ventilation. The air flowing through the through-opening can, for example, be supplied to a brake associated with the wheel, thereby advantageously ventilating the brake.

[0014] In order to ventilate the brake as required and to achieve advantageous aerodynamics of the vehicle as required, the invention provides that at least one closing element is assigned to the passage opening. The closing element is movable relative to the air guide element between at least one closed position and at least one open position. For example, the closing element is movable translationally and / or rotationally relative to the air guide element. In the closed position, at least a portion of the passage opening is covered by the closing element and thus closed. In particular, it can be provided that the closing element, in the closed position, covers and thus closes at least a predominant part, i.e., more than half, of the passage opening.Preferably, in the closed position, the closing element covers and thus closes the entire opening. Therefore, in the closed position, air cannot flow through the opening. In the open position, however, the closing element releases at least the opening, in particular more than half, and most preferably the entire opening, so that air, especially for venting the brake, can then flow through the opening.

[0015] It has proven particularly advantageous if the closing element is movably held on the air guide element between the open and closed positions. This ensures a compact and therefore aerodynamically efficient design of the air guide device.

[0016] In order to be able to open and close at least part of the passage opening as required, a further embodiment of the invention provides that the air guide device comprises an electrically and / or hydraulically and / or pneumatically operable actuator, by means of which the closing element can be moved between the closed position and the open position relative to the air guide element.

[0017] Another embodiment is characterized in that the air guide device comprises at least one spring element by means of which the closing element can be moved from the open position to the closed position and / or from the closed position to the open position. Preferably, the spring element is a mechanical spring. Using the spring element allows for a particularly simple and therefore aerodynamically advantageous, as well as lightweight and cost-effective, design.

[0018] To enable particularly easy movement of the closing element and thus achieve an aerodynamically advantageous design of the air guide device, a further embodiment of the invention provides that the air guide device comprises at least one bimetal and / or at least one shape memory alloy for moving the closing element. This means, in particular, that the closing element can be moved from the closed position to the open position and / or from the open position to the closed position by means of the bimetal or the shape memory alloy.

[0019] In a further, particularly advantageous embodiment of the invention, the wheel is rotatable about the wheel axis relative to the air guide element. The air guide element and the air guide surface thus remain in the lower region regardless of the wheel's rotation, enabling a particularly advantageous airflow pattern.

[0020] In a further, particularly advantageous embodiment of the invention, the air guide element is held on a wheel link, by means of which the wheel is pivotally mounted to the vehicle body. The wheel link allows, for example, compression and rebound movements of the wheel in the vehicle's vertical direction. Since the air guide element is preferably held at least indirectly on the wheel link, it can move with the wheel in the vehicle's vertical direction. This ensures that the air guide element always has an advantageous orientation or position relative to the wheel and thus, in particular, relative to the rim.

[0021] In particular, it is conceivable that the air guide element is held on a wheel carrier and thus moves with the wheel carrier and the wheel, while the wheel remains rotatable relative to both the wheel carrier and the air guide element. The wheel is rotatably mounted to the wheel carrier, for example, via a wheel bearing. Because the air guide element is held at least indirectly, for example via the wheel carrier, on the wheel arm, and in particular independently of the wheel, the air guide element is mounted rigidly to the axle. This ensures that the air guide element remains attached to the wheel arm during a wheel change, when the wheel is replaced with a different one. Furthermore, this arrangement allows for convenient access, especially to the brakes, which is particularly advantageous during repairs or maintenance.In particular, if the air guide element is held at least indirectly, and especially directly, on the wheel carrier, the air guide element can be steered along with the wheel carrier and thus with the wheel if the wheel is designed as a steered wheel, so that an advantageous and aerodynamically favorable alignment of the air guide element and the air guide fan relative to the wheel can be ensured.

[0022] Further insights underlying the invention are that, particularly in vehicles with high ground clearance, such as off-road vehicles, air can flow along the underbody of the vehicle and reach the inner sidewall, also known as the wheel flank, and strike the rim, especially its inner ring. This impact can cause excessive air resistance. Sporty vehicles with a lower ground clearance, in contrast, can have fixed guide vanes that direct fresh air to the brakes for cooling. However, this principle generates constant air resistance, and cooling the brakes is particularly undesirable when they are already at a low temperature. The air guide device according to the invention allows for advantageous and targeted airflow guidance.It is conceivable that the air guide surface or air guide element is curved at least in part, so that, for example, an uneven or curved air guide surface is directly connected to the air guide surface extending in the aforementioned plane.

[0023] Another embodiment is characterized in that the air guide element has at least one or more vortex generators projecting from the air guide surface in the transverse direction of the vehicle, particularly inwards, by means of which at least one vortex can be selectively generated in the air flowing towards the air guide element. This means that a targeted turbulence of the air can be achieved by means of the vortex generator, thus enabling particularly advantageous aerodynamics.

[0024] The aforementioned actuator for moving the closing element is, for example, a servo motor, which enables demand-based brake cooling. The bimetal or shape-memory alloy mentioned allows for temperature-dependent movement of the closing element. This means, in particular, that the shape-memory alloy or bimetal deforms when its temperature changes, thereby moving the closing element relative to the air guide element. This allows for the demand-based opening and closing of the passage opening in a particularly simple and thus aerodynamically advantageous manner.

[0025] A second aspect of the invention relates to a motor vehicle, preferably designed as a passenger car, which has at least one air guidance device according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention and vice versa.

[0026] Further advantages and details of the invention will become apparent from the following description and the accompanying drawings. These show: Fig. 1 a schematic and perspective under-view of an air guidance device for a motor vehicle according to a first embodiment, with an air guidance element which has an air guidance surface which extends in a plane perpendicular to a wheel rotation axis of a wheel; Fig. 2 a schematic and perspective underside view of the air guidance device according to a second embodiment; and Fig. 3 A schematic and perspective underside view of the air guidance device according to a third embodiment.

[0027] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0028] Fig. Figure 1 shows a schematic and perspective bottom view of a first embodiment of an air guide device for a motor vehicle designed as a passenger car. This means that the motor vehicle, in its fully manufactured state, includes the air guide device. Furthermore, the motor vehicle comprises a body designed as a self-supporting structure, which defines or forms an interior space within the vehicle. Persons, such as the driver, can be present in the interior space during a journey. The body includes a floor, also referred to as the underbody, which at least partially, and in particular at least predominantly or completely, defines the interior space downwards in the vertical direction of the vehicle. Fig. 1 a part of an underbody panel 10 of the motor vehicle is recognizable, by whose underbody panel 10 the floor is covered and thus lined downwards in the vehicle's vertical direction (z-direction in the vehicle coordinate system).

[0029] The motor vehicle also comprises an axle 12, which has at least or exactly two wheels spaced apart from each other in the transverse direction of the vehicle (y-direction in the vehicle coordinate system), also referred to as ground contact elements or vehicle wheels. Of the wheels of axle 12, Fig. 1. A wheel labeled 14 is visible. Wheel 14 is rotatable on a… Fig. The wheel 14 is mounted on a wheel carrier (not further specified) and is thus rotatable about a wheel axis relative to the wheel carrier and relative to the vehicle body. Furthermore, the wheel 14 is articulated, in particular pivotable, to the vehicle body via at least one wheel link 16. This means, in particular, that the wheel link 16 allows compression and rebound movements of the wheel 14 in the vertical direction of the vehicle and relative to the vehicle body. These compression and rebound movements of the wheel 14 occur, for example, when the wheel 14 rolls over an uneven surface while the vehicle is driving.

[0030] Wheel 14 can be a driven or driveable wheel, which can be driven by a drive motor of the vehicle, for example, an electric motor or an internal combustion engine. Wheel 14 can also be a non-driven or non-powered wheel. Furthermore, it is conceivable that wheel 14 is a non-steerable wheel, which cannot be steered relative to the vehicle body to effect changes in direction or lane changes of the vehicle. It is also conceivable that wheel 14 is a steerable wheel, which can be steered to effect lane changes, cornering, and changes in direction of the vehicle relative to the vehicle body and relative to the wheel guide 16, particularly in conjunction with the wheel carrier.

[0031] The wheel 14 has a rim 18 and a tire 20, which is mounted on the rim 18. The rim 18 has an inner diameter, which is perpendicular to the wheel's axis of rotation and is formed or limited by a rim ring 22 of the rim 18, also referred to simply as a ring. The air guide device comprises at least one air guide element 24 associated with the wheel 14, which has an air guide surface 26 for guiding air flowing towards the air guide surface 26 when the motor vehicle is in motion.

[0032] In order to achieve particularly advantageous aerodynamics of the motor vehicle and thus to be able to drive the motor vehicle in a particularly energy-efficient manner, the air guide surface 26, in particular at least a predominant part of the air guide surface 26 or preferably the entire air guide surface 26, extends in a plane perpendicular to the wheel axis of rotation, which, in particular when the wheel axis of rotation runs in the transverse direction of the vehicle or parallel to the transverse direction of the vehicle (y-direction), coincides with an xz-plane spanned by the longitudinal direction of the vehicle (x-direction) and the vertical direction of the vehicle (z-direction).Furthermore, the air guide surface 26 directly adjoins a lower region B of a flank 28 of the rim 18 or the rim ring 22 in the transverse direction of the vehicle and / or upwards in the vertical direction of the vehicle, wherein the air guide surface 26 also extends upwards in the vertical direction of the vehicle, in particular from the lower region B, over less than half of the inner diameter, and in particular over a maximum of one-third of the inner diameter. Specifically, the entire air guide surface 26 is arranged below the wheel guide 16 in the vertical direction of the vehicle. The air guide surface 26 prevents an excessive amount of air from flowing into the rim 18. It also prevents excessive ingress of dirt, snow, and / or other objects into the rim 18, thus preventing excessive corrosion of axle 12 components.It is important that the air guide element 14 and the rim ring 22 define a gap – preferably a very narrow one – which is at least large enough to prevent the air guide element 14 from rubbing against the rim when the wheel rotates. Preferably, the air guide surface 26 – viewed in the transverse direction (y-direction) of the vehicle – is positioned at the level of the rear rim flange (not shown in the figures) and preferably does not protrude from the rim towards the center of the vehicle. In this way, the air guide element protects the space enclosed by the rim or rim ring from air flowing past it into the wheel or rim along the inner wheel flank. Furthermore, the ingress of snow and other contaminants into the space enclosed by the rim is preferably prevented, or at least significantly reduced.

[0033] The air guide element 24 described above is essentially designed as a flat disc, the outer contour of which, at least in the illustrated embodiment, has the shape of a circular segment. A circular segment, also referred to as a circular section, is understood to be the portion of a circular area bounded by a circular arc and a circular chord. The radius of the circular segment corresponds essentially to, or is slightly smaller than, the inner diameter of the rim in the section surrounding the air guide element 24.

[0034] The wheel 14 is arranged at least partially, and in particular at least predominantly, in a wheel housing 30, which is at least partially, and in particular at least predominantly, bounded by a wheel arch liner 32 of the motor vehicle, also referred to as a wheel housing cover. In the case of the Fig. In the first embodiment shown in Figure 1, axle 12 is a front axle of the motor vehicle, so wheel 14 is a front wheel. Furthermore, in Fig. 1 Partially, a front bumper 34 of the motor vehicle is visible. Furthermore, it is evident that the air guide element 24 or the air guide surface 26 is a shield on the inner flank 28, also referred to as the wheel flank, in the lower area B of the front wheel. This prevents excessive ingress of dirt and air into the rim 18.

[0035] In the first embodiment, the entire air guide surface 26 is free of any through-openings penetrating the air guide surface 26. In contrast, the Fig. 2 a second embodiment of the air guide device. In the second embodiment, the air guide element 24 has at least or exactly one through-opening 36 penetrating the air guide surface 26. A closing element 38 is associated with the through-opening 36, which is located between at least one in Fig. The closing element 38 is movable relative to the air guide element 24 in the open position O and a closed position, at least indirectly, and in particular directly, held on the air guide element 24. Thus, the closing element 38 is movable along with the air guide element 24. Furthermore, the wheel 14 is rotatable about its axis of rotation relative to the air guide element 24. In the closed position, the closing element 38 closes the entire passage opening 36, so that no air can flow through the passage opening 36 in the closed position. In the open position O, however, the closing element 38 releases the passage opening 36, so that air can then flow through the passage opening 36.

[0036] Wheel 14 is, for example, associated with a brake, not visible in the figures, designed in particular as a friction brake, by means of which wheel 14 and thus the vehicle as a whole can be braked. In particular, the brake is a component of the vehicle's service brake. In the open position O, air can flow through the released passage 36, and the air flowing through the passage 36 can, for example, be supplied to the aforementioned brake. This allows for brake ventilation, in which the brake is cooled by means of the air flowing through the passage 36. Since the passage 36 can be closed and opened as required by means of the closing element 38, the brake can be cooled as needed.For this purpose, the air guidance device can comprise at least one actuator, for example, designed as a servo motor, which can be operated hydraulically and / or pneumatically and / or electrically. By operating the actuator, the closing element 38 can, for example, be moved relative to the air guidance element 24 from the open position O to the closed position and / or from the closed position to the open position. Alternatively or additionally, at least one or more passive elements, such as at least one spring and / or at least one bimetal and / or at least one shape memory alloy, can be assigned to the closing element 38 in order to move the closing element 38 relative to the air guidance element 24 from the closed position to the open position O and / or from the open position O to the closed position.

[0037] For example, if the brake temperature is lower than a predefined or predetermined threshold, the closing element 38 is in the closed position, as brake cooling is not required. This allows for advantageous aerodynamics. If the brake temperature corresponds to or exceeds the threshold, the closing element 38 moves from the closed position to the open position O, allowing cooling air to flow through the opening 36 to the brake and cool it. If this cooling causes the brake temperature, also referred to as the brake temperature, to fall below the threshold, the closing element 38 moves from the open position O to the closed position to close the opening 36 again.

[0038] Depending on the vehicle, design, etc., it may be advantageous to provide additional air guide elements. Fig.Figure 3 shows a third embodiment of the air guidance device. In this third embodiment, the air guidance element has several spaced-apart vortex generators 40, which project inwards from the air guidance surface 26 in the transverse direction of the vehicle. Each vortex generator 40 is, for example, curved. Each vortex generator 40 is designed to selectively swirl the air flowing towards the air guidance element 24, thereby generating at least one or more vortices in the air flowing towards the air guidance element 24. This allows the air resistance to be kept particularly low. In this third embodiment, the vortex generators 40 are arranged successively in the longitudinal direction of the vehicle, such that the vortex generators 40 overlap each other at least partially in pairs in the longitudinal direction of the vehicle.

Claims

[1] Air guiding device for a motor vehicle, with at least one wheel (14) of the motor vehicle, which is rotatable about a wheel rotation axis and has a rim (18) with an inner diameter, and with an air guiding element (24) assigned to the wheel (14), which has an air guiding surface (26) for guiding air flowing onto the air guiding surface (26) when the motor vehicle is traveling, wherein the air guiding surface (26) extends in a plane running perpendicular to the wheel rotation axis characterized byin that the air guiding surface (26) is directly adjacent to a lower region (B) of an inner flank (28) of the rim (18) in the vehicle's vertical direction inwards in the vehicle's transverse direction and / or upwards in the vehicle's vertical direction and extends in the vehicle's vertical direction over less than half the inner diameter, in that the air guiding element (24) has at least one through-opening (36) penetrating the air guiding surface (26), and in that a closing element (38) is assigned to the through-opening (36), which closing element is movable relative to the air guiding element (24) between at least one closed position closing at least a partial region of the through-opening (36) and at least one open position (O) releasing the partial region. [2] Air guiding device according to claim 1, characterized by that the closing element (38) is movably held on the air guiding element (24). [3] Air guiding device according to claim 1 or 2, characterized bythat an electrically and / or hydraulically and / or pneumatically operable actuator is provided, by means of which the closing element (38) is movable relative to the air guiding element (24). [4] Air guiding device according to one of claims 1 to 3, characterized by that at least one spring element is provided for moving the closing element (38). [5] Air guiding device according to one of claims 1 to 4, characterized by that at least one bimetal and / or at least one shape memory alloy is provided for moving the closing element (38). [6] Air guiding device according to one of the preceding claims, characterized by that the wheel (14) is rotatable relative to the air guiding element (24) and / or the air guiding element (24) is held on a wheel guide (16), via which the wheel (14) is held in an articulated manner on a body of the motor vehicle. [7] Air guiding device according to one of the preceding claims, characterized bythat the air guiding element (24) has at least one vortex generator (40) projecting from the air guiding surface (26) in the transverse direction of the vehicle, by means of which at least one vortex of the air flowing towards the air guiding element (24) can be specifically generated. [8] Motor vehicle, with at least one air guiding device according to one of the preceding claims.

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