Rear diffuser and vehicle with such a rear diffuser

Abstract

The invention relates to a rear diffuser for a vehicle (18), wherein the rear diffuser comprises a diffuser frame (1) that can be rigidly connected to a vehicle structure and a diffuser flap (2) that is movably connected to the diffuser frame (1), wherein the diffuser flap (2) is pneumatically movable between a closed position and an open position. The rear diffuser according to the invention is characterized in that the diffuser frame (1) and the diffuser flap (2) are connected to each other via at least one elastomeric cable (3), wherein the length of the elastomeric cable (3) and the attachment points of the elastomeric cable (3) on the diffuser frame (1) and on the diffuser flap (2) are coordinated such that the elastomeric cable (3) is tensioned at the latest when the diffuser flap (2) is moved out of the closed position.

Description

[0001] The invention relates to a rear diffuser for a vehicle, according to the preamble of claim 1, and a vehicle comprising such a rear diffuser.

[0002] A rear diffuser of the type discussed here is disclosed, for example, in DE 10 2013 105 842 B4. With the help of such a rear diffuser, the airflow characteristics of a vehicle can be specifically adjusted. The rear diffuser comprises a part that can be pivoted relative to the vehicle structure in the direction of the road, allowing the vehicle's silhouette to be specifically altered. Thus, particularly as the vehicle's speed increases, extending the rear diffuser can reduce the vehicle's aerodynamic drag, although this also involves reducing the vehicle's downforce or increasing its lift. By reducing aerodynamic drag, the vehicle's energy consumption can be reduced, thus increasing its range.

[0003] The rear diffuser can be extended and retracted electromechanically or pneumatically, for example. However, electromechanical operation carries an increased risk of damage to the actuators and mechanisms used, such as electric motors, levers, and the like. This creates the risk that debris, gravel, stones, and the like could be thrown up while driving and strike the extended rear diffuser from below. This force is then transmitted to the suspension and actuator. If the actuators / mechanics are damaged, the rear diffuser may no longer be able to be extended and retracted reliably. Furthermore, the rear diffuser could touch down when driving over a bump, for example, which could also cause damage. An electromechanical adjustment drive also requires a comparatively large installation space and is relatively expensive.

[0004] When the rear diffuser is opened or extended, a gap forms between the vehicle structure and the diffuser flap. This gap can be sealed using a sealing element, for example in the form of a bellows. This prevents environmental influences such as dirt or moisture from penetrating the space formed between the corresponding diffuser flap and the vehicle structure. It also reduces air flow losses caused by turbulence around the open diffuser flap. At low temperatures, particularly below freezing, ice can form on this sealing element, which can make it difficult or even completely prevent the diffuser flap from extending and retracting. When the diffuser flap is extended, snow or slush can also accumulate between the individual folds of the bellows, which can prevent the diffuser flap from retracting.

[0005] The present invention is based on the object of providing an improved rear diffuser for a vehicle, which is characterized by greater robustness and at the same time reduced manufacturing costs.

[0006] According to the invention, this object is achieved by a rear diffuser having the features of claim 1. Advantageous embodiments and further developments as well as a vehicle with such a rear diffuser emerge from the dependent claims.

[0007] A generic rear diffuser for a vehicle, wherein the rear diffuser has a diffuser frame that can be firmly connected to a vehicle structure and a diffuser flap that is movably connected to the diffuser frame, wherein the diffuser flap is pneumatically movable between a closed position and an open position, is further developed according to the invention in that the diffuser frame and the diffuser flap are connected to one another via at least one elastomer cable, wherein the length of the elastomer cable and the fastening points of the elastomer cable on the diffuser frame and on the diffuser flap are coordinated with one another in such a way that the elastomer cable is tensioned at the latest when the diffuser flap is moved out of the closed position.In other words, the elastomer cable may already have a certain pre-tension in the closed position of the diffuser flap and is further tensioned when the diffuser flap is moved to its open position, or the elastomer cable may be tension-free and slack when the diffuser flap is in the closed position and is only tensioned when the diffuser flap is moved to its open position.

[0008] The invention is therefore based on the idea of ​​using an elastomer cable, for example a rubber cable, to exert a restoring force on the diffuser flap when it is pneumatically moved from the closed position to the open position. This is a particularly simple embodiment that eliminates the need for expensive and easily damaged electromechanical actuating components. The integration of the corresponding pneumatics and the elastomer cable requires less installation space compared to an electromechanical actuator with associated suspension. By removing the corresponding pneumatic actuation, the diffuser flap can be moved back to the closed position automatically and without additional actuating energy using the tension force of the elastomer cable.The elastomer cable is designed and attached to the diffuser frame and the diffuser flap in such a way that the tension created in the elastomer cable is sufficient to hold the diffuser flap in the closed position when no pneumatic pressure is applied. However, the elastomer cable can also be pre-tensioned, so that this pre-tension force must first be released via the appropriate pneumatic system before the diffuser flap can be opened.

[0009] In the simplest case, the elastomer cable is attached to the diffuser flap at one end and to the diffuser frame at the opposite end. When the diffuser flap is opened, the elastomer cable is stretched, causing the restoring force to increase proportionally with the degree of opening. Multiple elastomer cables can also be used.

[0010] All common elastomers can be used to form the elastomer rope, especially in the form of vulcanizates of natural rubber or silicone rubber.

[0011] The rear diffuser according to the invention is also particularly fail-safe. If the pneumatic system used to extend it is damaged, the diffuser flap is automatically moved to the closed position due to the restoring force exerted by the elastomer cable. This is not possible with a purely electromechanical adjustment system in the event of an actuator failure or even structural damage to the suspension. This prevents the diffuser flap from dangling uncontrollably in the fully open position in the event of damage.

[0012] An advantageous development of the rear diffuser provides that, when installed as intended on a vehicle, the diffuser flap is pivotally connected to the diffuser frame at a first edge region facing the front of the vehicle via a rotation axis running in the transverse direction of the vehicle, and the elastomer cable is attached to the diffuser flap at a second edge region opposite the first edge region. This is a particularly clever design. When opening and closing the diffuser flap, it rotates around the rotation axis. The further the suspension point of the elastomer cable on the diffuser flap is from the rotation axis, the larger the corresponding lever arm, so that the restoring force required to close the diffuser flap can be reduced.

[0013] According to a further advantageous embodiment of the rear diffuser according to the invention, the elastomer cable is designed as a self-contained elastomer band and is guided around a first deflection pulley connected to the diffuser flap. This allows the force acting in the individual strands of the elastomer band to be halved.

[0014] The diffuser frame preferably has a deflection pulley support comprising a second deflection pulley and a third deflection pulley, wherein a first band section guided around the first deflection pulley is guided around the second deflection pulley, and a second band section guided around the first deflection pulley is guided around the third deflection pulley. This allows the installation space used for accommodating or stowing the elastomer band to be specifically optimized and the extension direction of the elastomer cable or the elastomer band to be specifically adjusted when opening the diffuser flap. This also ensures a reliable movement sequence during the opening and closing of the diffuser flap.

[0015] A further advantageous embodiment of the rear diffuser according to the invention further provides that, when installed as intended on a vehicle, the first deflection roller at least partially overlaps with the second and / or third deflection roller in the closed position of the diffuser flap in the vehicle's longitudinal direction. In other words, the deflection roller carrier is thus positioned at essentially the same height as the first deflection roller, viewed in the vehicle's longitudinal direction. This further facilitates the kinematic movement sequence during the opening and closing of the diffuser flap. Thus, the corresponding components are positioned "one below the other" in the vehicle's vertical direction.

[0016] A further advantageous embodiment of the rear diffuser according to the invention further provides that the diffuser frame has a deflection rod support, wherein the elastomer band is guided around a deflection rod carried by the deflection rod support, and wherein the first and second band sections converge at the deflection rod. This facilitates the installation of the elastomer band. The elastomer band only needs to be pulled onto the respective deflection rollers or the deflection rod. As already mentioned, the elastomer band could also be designed as an elastomer cable, so that, for example, the two ends of the elastomer cable could be connected to the diffuser frame or the deflection rod. However, this requires a rather complex fastening of the elastomer cable.

[0017] When installed as intended on a vehicle, the deflection rod support is preferably translationally displaceable, in particular adjustably displaceable, along the diffuser frame at least in the longitudinal direction of the vehicle. This further facilitates the kinematic movement sequence when opening and closing the diffuser flap. In addition, the load on the elastomer band is reduced. When the diffuser flap opens, the elastomer band pulls on the deflection rod, whereby the deflection rod support is moved towards the deflection roller support, i.e. in particular towards the rear of the vehicle. Accordingly, when the diffuser flap is closed, the deflection rod support moves away from the deflection roller support, i.e. towards the front of the vehicle. In particular, the rear diffuser rises geodetically towards the rear of the vehicle, so that the deflection rod support also moves vertically, i.e. in the vertical direction of the vehicle. By providing mobility, overstretching of the elastomer band can be counteracted.

[0018] Preferably, the deflection rod support is adjustable by means of an actuator, meaning it can be moved to a specific target position. For this purpose, the same pneumatic actuator that is used to open the diffuser flap is preferably used. However, it is also conceivable to use an additional actuator, even an electromechanical actuator, to move the deflection rod support along the diffuser frame. Due to the elastic coupling of the diffuser flap and the deflection rod support via the elastomer band, no forces acting in the direction of the closed position can be transmitted from the diffuser flap to a corresponding electromechanical actuator.Only forces acting in the direction of the open position are passed on to the electromechanical actuator, but stones hitting the diffuser flap from below or the diffuser flap touching the ground create forces acting in the direction of the closed position, so that the potential for damage to any electric motor present is low.

[0019] The deflection rod is preferably suspended from the deflection rod support so that it can rotate around its central axis. This facilitates the unwinding of the elastomer band against the deflection rod support, which further improves the kinematic movement sequence when opening and closing the diffuser flap. This reduces the friction between the elastomer band and the deflection rod during the movement sequence. In general, a cylinder or sleeve could also be mounted on the deflection rod, so that the corresponding cylinder could be considered a fourth deflection pulley. It is also possible to replace the first, second, and / or third deflection pulley with corresponding rigidly connected or rotatable deflection rods.

[0020] Instead of an elastomer band or elastomer cable, a rigid cable, band, or even a chain could be used in such an embodiment to connect the diffuser flap to the diffuser frame via a translationally displaceable deflection rod support. However, due to the elasticity of the elastomer band, the robustness of the rear diffuser according to the invention can be further increased. This means that forces acting in the direction of the open position are transmitted in a weakened manner to any electric motor used for translationally displacing the deflection rod support, in contrast to the provision of a comparatively rigid cable, band, belt, chain, or the like.

[0021] A further advantageous embodiment of the rear diffuser according to the invention further provides that the deflection rod support is supported on the diffuser frame via a spring and / or damper acting in the translational direction, and / or the mass of the deflection rod support is designed to be large enough that, when the pneumatic system is deactivated, the deflection rod support slides down the diffuser frame, pulling the diffuser flap into the closed position via the elastomer band. This makes it possible to further support the movement of the diffuser flap into the closed position without the need for additional actuators designed separately from the pneumatic system.The spring acting in the translational direction can be provided between the deflection rod support and the deflection roller support, so that the spring is compressed when the diffuser flap opens, and / or a spring can be provided on the side of the deflection rod support facing away from the deflection roller support, which is accordingly extended. At least one spring can be provided. It is also conceivable to provide more than one spring on each side. In particular, these are coil springs. The arrangement of the respective dampers can be designed analogously.

[0022] Additionally or alternatively, the mass of the deflector rod support can be selected to be correspondingly high so that, when the diffuser frame rises geodetically towards the rear of the vehicle, the deflector rod support, due to its weight, pulls the diffuser flap upwards into the closed position when it slides down the diffuser frame. Depending on the angle at which the diffuser frame rises geodetically towards the rear of the vehicle and the weight of the diffuser flap, a higher or lower weight for the deflector rod support is sufficient. The deflector rod support can be accommodated in a corresponding guide on the diffuser frame. This guide can contain a lubricant such as oil, grease, graphite or the like, allowing the deflector rod support to slide particularly easily relative to the diffuser frame. It is also conceivable for the deflector rod support to be mounted on rollers on the diffuser frame.

[0023] According to a further advantageous embodiment of the rear diffuser according to the invention, an air cushion, comprising at least one air chamber and at least one actuatable valve for each air chamber, is arranged in a receiving space between the diffuser frame and the diffuser flap, wherein the air cushion is pneumatically inflatable to move the diffuser flap into the open position, and the air cushion is foldable to move the diffuser flap into the closed position by a restoring force imposed on the diffuser flap via the elastomer cable. In general, there are various ways in which the diffuser flap could be pneumatically actuated. For example, appropriate pneumatic cylinders could be provided. However, a particularly space-saving and cost-effective embodiment is the use of air cushions. The air cushion can have one or more air chambers.Each air chamber has at least one valve that can be opened or closed by a corresponding control system. Each air chamber can be assigned a single valve, which is used equally for filling and venting the air chamber. A separate supply valve and a separate vent valve can also be provided for each air chamber. Some air chambers can have a single valve and other air chambers can have two valves (i.e., one supply valve and one vent valve each). By closing any valve, the diffuser flap can then be locked in the respective position. It is conceivable to move the diffuser flap continuously or incrementally between different stages between the closed and open positions. In particular, the degree of opening is selected depending on the vehicle's speed.To close the diffuser flap again, simply open the corresponding (vent) valve to release air from the air chamber(s). The elastomer cable or band compresses the air cushion via the restoring force exerted on the diffuser flap, forcing the air present in the air chamber(s) out of the air cushion.

[0024] The respective valves are preferably held closed by actuating energy. If a technical failure occurs, for example, so that no electrical power can be drawn from the vehicle's electrical system, the valves or vent valves open automatically. The restoring force applied via the elastomer band enables the diffuser flap to close automatically without actuating energy.

[0025] The valve(s) can also be designed as a pressure relief valve. If a force is applied to the diffuser flap in the direction of the closed position, this can cause the pressure in the air cushion to rise. The automatic opening of the valves then allows the air to escape from the air cushion, allowing the diffuser flap to retract in response to the force. The valves can be designed as passive or active pressure relief valves. With a passive pressure relief valve, the valve opens automatically when a critical pressure is reached. With an active pressure relief valve, the pressure in the air cushion is recorded by a sensor, and when a critical pressure level is reached, the respective valve is opened by a control unit.

[0026] A further advantageous embodiment of the rear diffuser according to the invention further provides for a sealing element connected to the diffuser frame and the diffuser flap, in particular designed as a bellows, wherein the sealing element seals a gap created between the diffuser frame and the diffuser flap when the diffuser flap is opened, and a heating device integrated into the sealing element is provided, preferably designed as a heating wire. As mentioned above, at low temperatures, in particular below freezing, ice and snow can accumulate on the sealing element or the bellows. Ice and snow can disrupt the movement of the diffuser flap when it opens and closes. Any snow or ice can be melted via the heating device, so that the diffuser flap can be opened and closed reliably even in winter.A heating wire design has proven particularly effective. Heating wires are inexpensive and widely available, allowing for easy integration. However, it could also be a heating device that also utilizes natural and / or forced convection and / or radiation to defrost the sealing element. The heating device could also include a type of hair dryer and / or infrared heater.

[0027] Particularly preferably, the heating device can be activated automatically depending on an ambient temperature measured by the vehicle. Any activation temperature can be set, such as 4°C, 0°C, or even a temperature below freezing. Generally, it is conceivable for the rear diffuser according to the invention itself to comprise a corresponding temperature sensor and a corresponding control for activating the heating device depending on a corresponding temperature signal.

[0028] A vehicle according to the invention has at least one rear diffuser as described above. The vehicle can be any road vehicle, such as a car, truck, van, bus, or the like. Generally, it could also be a rail vehicle.

[0029] A control method according to the invention for actuating the rear diffuser provides that, to open the diffuser flap, compressed air is supplied to the air cushion so that the air cushion inflates; to lock the diffuser flap in the current position, respective valves assigned to the air cushion are closed so that air can neither escape from the air cushion nor be supplied to the air cushion; and, to close the diffuser flap, valves assigned to the air cushion are opened so that the compressed air in the air cushion can escape, in particular into the environment.

[0030] Further advantageous embodiments of the rear diffuser according to the invention and of the vehicle also emerge from the exemplary embodiments which are described in more detail below with reference to the figures.

[0031] Showing: Fig. 1 a schematic side view of a vehicle according to the invention, comprising a rear diffuser according to the invention; Fig. 2 a schematic detailed view of the rear diffuser according to the invention according to a preferred embodiment; Fig. 3 a schematic perspective view of an elastomer band; Fig. 4 a schematic sectional view through the rear diffuser according to the invention according to the preferred embodiment; Fig. 5 a schematic representation of a free body diagram of a deflection bar support; and Fig. 6 a schematic detailed representation of a heating device for a sealing element.

[0032] Rear diffusers can be used to positively influence the airflow around the vehicle, especially at high speeds. This allows the vehicle's drag and downforce to be specifically adjusted by extending the rear diffuser. Fig. Figure 1 shows a particularly simple embodiment of a rear diffuser according to the invention. The rear diffuser comprises a diffuser frame 1 rigidly connected to the vehicle 18 and a diffuser flap 2 movably connected to the diffuser frame 1. The diffuser flap 2 is pneumatically movable between a closed position and an open position. Fig. 1 shows the diffuser flap 2 in an at least partially open position or the open position. A gap 16 is formed between the diffuser frame 1 and the diffuser flap 2. The gap 16 can be closed by a Fig. 5 shown optional sealing element, advantageously designed as a bellows 15. The corresponding pneumatic actuator for moving the diffuser flap 2 is shown in Fig. 1 not shown.

[0033] According to the invention, the diffuser frame 1 and the diffuser flap 2 are connected to one another via at least one elastomer cable 3. When the diffuser flap 2 is opened, the elastomer cable 3 is stretched and thus exerts a restoring force on the diffuser flap 2. The elastomer cable 3 can be pretensioned so that it already exerts a corresponding restoring force in the closed position of the diffuser flap 2. At the latest when the diffuser flap 2 is opened, i.e., when the diffuser flap 2 is moved out of the closed position, the elastomer cable 3 is tensioned. If the pneumatic system for moving the diffuser flap 2 fails, it is thus possible to reliably move the diffuser flap 2 back to the closed position.

[0034] How Fig. 1 shows, in the simplest case, the elastomer cable 3 can be rigidly connected to the diffuser frame 1 and the diffuser flap 2. Preferably, the diffuser flap 2 is pivotably connected to the diffuser frame 1 at a first edge region 4.1 facing the front of the vehicle in the vehicle longitudinal direction X via a rotation axis 5 running in the vehicle transverse direction (see the curved double arrow). The elastomer cable 3 is preferably attached to the diffuser flap 2 at a second edge region 4.2 opposite the first edge region 4.1. Thus, the extended lever arm allows the restoring force required to close the diffuser flap 2 to be reduced.

[0035] Fig. 2 shows a preferred embodiment of the rear diffuser according to the invention. The elastomer cable 3 is designed as a self-contained elastomer band 6. A first deflection pulley 7.1 is attached to the diffuser flap 2. A deflection pulley carrier 8 is provided on the diffuser frame 1, comprising a second and a third deflection pulley 7.2, 7.3. A first band section 9.1, guided around the first deflection pulley 7.1, is guided around the second deflection pulley 7.2, and a second band section 9.2, guided around the first deflection pulley 7.1, is guided around the third deflection pulley 7.3. Furthermore, the diffuser frame 1 has a deflection rod carrier 10 carrying a deflection rod 11. The first and second band sections 9.1, 9.2 converge at the deflection rod 11. The deflection rod support 10 can be rigidly connected to the diffuser frame 1 or can also be designed to be translationally movable relative to the diffuser frame 1, at least in the direction of the vehicle longitudinal direction X.

[0036] Fig. 2 also shows the pneumatic system used to extend or open the diffuser flap 2. The pneumatic system comprises an air cushion 13 arranged in a receiving space 14 formed between the diffuser frame 1 and the diffuser flap 2, again having air chambers not shown in detail. A pressurized gas, in particular air, can be introduced into the air cushion 13 via at least one actuatable valve 21 via a compressor or a pressure accumulator. The valve 21 can be used equally for filling and venting the air cushion 13. For this purpose, the valve 21 can be connected to corresponding pneumatic circuits. A separate vent valve (not shown) can also be provided for at least one air chamber of the air cushion 13. The vent valves can, in particular, communicate directly with the environment.If the valve 21 is closed, the air remains in the air cushion 13, whereby a pressure level higher than atmospheric exists. By unfolding the air cushion 13, the diffuser flap 2 is moved into the open position. Via a corresponding control device (not shown), the respective valves 21 can be opened and closed or connected to different pneumatic circuits. The air cushion 13 can be arranged both in front of and behind the deflection pulley carrier 8 and / or the first deflection pulley 7.1, viewed in the vehicle's longitudinal direction X. For example, the elastomer band 6 could also be guided laterally around the air cushion 13, viewed in the vehicle's transverse direction.

[0037] Fig. Figure 3 shows the elastomer band 6, the second deflection roller 7.2, the deflection bar support 10, the deflection bar 11, and the deflection roller support 8 in detail. The first deflection roller 7.1 can be attached to a frame 19. The frame 19 is in turn connected to the diffuser flap 2 or formed onto it (see Fig. 2). The frame 19 or the deflection roller carrier 8 can have an optional element 20, via which the frame 19 and the deflection roller carrier 8 can establish a positive connection with one another when the diffuser flap 2 is in the closed position. In particular, the frame 19 and the deflection roller carrier 8 can engage with one another. This also makes it possible to hold the diffuser flap 2 in the closed position when the elastomer band 6 is not tensioned. The element 20 or the locking mechanism can be released by a controllable actuator.

[0038] Fig. Figure 4 shows the respective components again in a more detailed sectional view. The deflection rod support 10 can be supported on the diffuser frame 1 via at least one spring 12 and / or a damper (not shown in detail). The spring 12 acts in the translation direction of the deflection rod support 10, indicated by a double arrow. If the diffuser flap 2 is opened, the spring 12 is compressed, resulting in an increase in the restoring force exerted on the diffuser flap 2.

[0039] Additionally or alternatively, the mass of the deflection rod support 10 can be specifically adjusted to support the closing of the diffuser flap 2 due to the weight force. The functional principle is explained using Fig. 5 is explained in more detail. Fig. Figure 5 shows a free-body diagram of the deflection rod support 10. The respective cable forces F imposed via the first and second belt sections 9.1, 9.2 and the weight force G of the deflection rod support 10 are shown. The diffuser frame 1 rises geodetically against the vehicle's longitudinal direction X towards the rear of the vehicle, which is indicated by a dotted line. The corresponding cable forces F act in the translational direction. Due to the tilting at the angle α, the weight force G also acts, but proportionally, in the translational direction and is directed opposite to the cable forces F. Thus, the deflection rod support 10 can close the diffuser flap 2 by sliding down the diffuser frame 1 due to its weight force G. In general, it is not even necessary for the elastomer belt 6 or elastomer cable 3 to be elastic for this purpose. In general, a rigid rope, band, strap, chain or the like could also be used.However, the provision of a certain elasticity has a positive effect on the mechanical relief of the force-transmitting elements when a force is applied to the diffuser flap 2 into the closed position.

[0040] Fig. 6 shows a larger view of the rear diffuser with the sealing element shown. The bellows 15 has a heating device, advantageously embodied here as a heating wire 17. The heating device can be specifically activated to defrost the bellows 15. This prevents ice, snow, slush, or the like from accumulating on the sealing element in winter temperatures. This reliably ensures the opening and closing of the diffuser flap 2. In particular, the heating device can be activated automatically depending on the ambient temperature. The heating device is particularly advantageously activated when the ambient temperature falls below 0°C. 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 2013 105 842 B4

[0002]

Claims

[1] Rear diffuser for a vehicle (18), wherein the rear diffuser has a diffuser frame (1) which can be firmly connected to a vehicle structure and a diffuser flap (2) which is movably connected to the diffuser frame (1), wherein the diffuser flap (2) is pneumatically movable between a closed position and an open position, characterized by that the diffuser frame (1) and the diffuser flap (2) are connected to one another via at least one elastomer cable (3), wherein the length of the elastomer cable (3) and the fastening points of the elastomer cable (3) on the diffuser frame (1) and on the diffuser flap (2) are coordinated with one another in such a way that the elastomer cable (3) is tensioned at the latest when the diffuser flap (2) is moved out of the closed position. [2] Rear diffuser according to claim 1, characterized bythat when installed as intended on a vehicle (18), the diffuser flap (2) is pivotably connected to the diffuser frame (1) at a first edge region (4.1) facing the front of the vehicle via a rotation axis (5) running in the transverse direction of the vehicle, and the elastomer cable (3) is fastened to the diffuser flap (2) at a second edge region (4.2) opposite the first edge region (4.1). [3] Rear diffuser according to claim 1 or 2, characterized by that the elastomer cable (3) is designed as a self-contained elastomer band (6) and is guided around a first deflection roller (7.1) connected to the diffuser flap (2). [4] Rear diffuser according to claim 3, characterized bythat the diffuser frame (1) has a deflection roller carrier (8) comprising a second deflection roller (7.2) and a third deflection roller (7.3), wherein a first band section (9.1) guided around the first deflection roller (7.1) is guided around the second deflection roller (7.2) and a second band section (9.2) guided around the first deflection roller (7.1) is guided around the third deflection roller (7.3). [5] Rear diffuser according to claim 4, characterized by that when installed as intended on a vehicle (18), the first deflection roller (7.1) in the closed position of the diffuser flap (2) in the vehicle longitudinal direction (X) at least partially overlaps with the second deflection roller (7.2) and / or third deflection roller (7.3). [6] Rear diffuser according to claim 4 or 5, characterized bythat the diffuser frame (1) has a deflection rod support (10), wherein the elastomer band (6) is guided around a deflection rod (11) carried by the deflection rod support (10), and wherein the first and second band sections (9.1, 9.2) converge at the deflection rod (11). [7] Rear diffuser according to claim 6, characterized by that when installed as intended on a vehicle (18), the deflection rod support (10) is translationally displaceable at least in the vehicle longitudinal direction (X) along the diffuser frame (1), in particular adjustably displaceable. [8] Rear diffuser according to claim 7, characterized bythat the deflection rod carrier (10) is supported on the diffuser frame (1) via a spring (12) and / or damper acting in the direction of translation and / or the mass of the deflection rod carrier (10) is designed so large that the deflection rod carrier (10) pulls the diffuser flap (2) into the closed position via the elastomer band (6) when the pneumatic application is deactivated by sliding down the diffuser frame (11). [9] Rear diffuser according to one of claims 1 to 8, characterized byin that an air cushion (13), comprising at least one air chamber and at least one actuatable valve (21) for each air chamber, is arranged in a receiving space (14) formed between the diffuser frame (1) and the diffuser flap (2), wherein the air cushion (13) is pneumatically inflatable in order to move the diffuser flap (2) into the open position and the air cushion (13) is foldable in order to move the diffuser flap (2) into the closed position by means of a restoring force imposed on the diffuser flap (2) via the elastomer cable (3). [10] Rear diffuser according to one of claims 1 to 9, characterized bya sealing element connected to the diffuser frame (1) and the diffuser flap (2), in particular designed as a bellows (15), wherein the sealing element seals a gap (16) created between the diffuser frame (1) and the diffuser flap (2) when the diffuser flap (2) is opened, and a heating device integrated into the sealing element, preferably designed as a heating wire (17). [11] Vehicle (18), characterized by at least one rear diffuser according to one of claims 1 to 10.

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