Patent Publication Number: US-2013252538-A1

Title: Cooler blind

Description:
The present application relates to a device for altering a flow cross-section of an air passage opening in a motor vehicle, for altering an air mass flow rate to a motor vehicle unit, such as a cooler, the device comprising a device frame having the air passage opening, further comprising at least two substantially rigid shutter components, which are adjustable with respect to the device frame between at least two different relative positions in which they cover the air passage opening to different extents, and comprising a drive for providing a driving force for the relative movement of the shutter components with respect to the device frame. 
     Devices of this type are sufficiently known in the form of air flap systems in vehicles. For example, DE 10 2009 043 064 A discloses a device of this type. 
     German utility model DE 87 00 945 U discloses a blind which can be wound up and unwound, consisting of a flexible material web, for altering the flow cross-section of an air passage opening by unwinding and winding up the blind. In this context, the blind is introduced into or withdrawn from the air passage opening to different extents. 
     Further, air flap systems are known in which each air flap is pivotable about a flap pivot axle which extends in the longitudinal direction of the air flap, so as to alter a flow cross-section in an air passage opening in a device frame. 
     In all of these known air flap systems, as well as in that of the present invention, the position of the shutter components with respect to the device frame is adjusted as a function of an airflow requirement of a unit positioned downstream from the air passage opening in the airflow direction. 
     The convective cooling requirement of the unit can be determined in the vehicle by way of one or more parameters, such as the cooling water temperature, the rotational speed of the engine, the throttle flap opening width, the vehicle speed and the like. 
     A drawback of the type of air flap system known from DE 10 2009 043 064 A is that the shutter components of the known air flap system are provided with a first gap width, and a grille having rigid shutter components, which are immovable with respect to the device frame and have approximately the same gap width, with respect to which the movable shutter components are adjusted, is arranged on the device frame. In this context, the rigid and the movable shutter components extend substantially mutually parallel. Thus, the maximum achievable flow cross-section of the air passage opening is defined by the size of the shutter elements and the gap width determined thereby. 
     A drawback of the blind known from DE 87 00 945 U is the flexibility of the material web which is used as the blind, which cannot withstand the back pressures which occur in normal driving operation unless additional reinforcing measures are used. 
     A drawback of the shutter components which can exclusively be rotated individually or together with respect to the device frame is that, because they can turn, they require a relatively large amount of installation space so as to be able to be accommodated on the device frame in different rotational positions. 
     The object of the present invention is therefore to provide an air flap system of the type stated at the outset which makes a larger maximum flow cross-section possible than the prior art, with otherwise substantially the same dimensions of the device frame as in the prior art, whilst simultaneously the installation space required for accommodating the shutter components in different relative positions with respect to the device housing should as a result be as small as possible. 
     This object is achieved according to the invention by a device of the type stated at the outset in which at least two shutter components, which are directly adjacent in the direction of relative movement, are interconnected so as to be pivotable with respect to one another about a shutter pivot axle. 
     The shutter components of the device according to the invention are thus arranged in the manner of roller shutters, are themselves substantially rigid, that is to say inherently rigid, and can thus even withstand large back pressure, and are interconnected so as to be pivotable with respect to one another, as a result of the relative movability about the shutter pivot axle, in such a way that they can be moved out of the air passage opening in the manner of a roller blind without requiring additional installation space. 
     To introduce the interconnected shutter components into the air passage opening, thereby reducing the flow cross-section thereof, and to withdraw them, thereby increasing the flow cross-section thereof, only installation space approximately corresponding to the width dimension of the shutter components is required in the air passage opening itself. 
     So as to be able to cover and uncover as large an air passage opening as possible by way of the device frame and/or ensure a maximum movability of a shutter component arrangement of pivotably interconnected blind components for a predetermined size of the air passage opening, it may be provided that the device comprises a plurality of shutter components, of which all of the shutter components which are directly adjacent in the direction of relative movement are interconnected so as to be pivotable about a respective shutter pivot axle. 
     For a predetermined size of the air passage opening, the shutter components become smaller as the number increases in the direction of the spacing between two directly adjacent blind pivot axles, and this leads to a higher proportion of articulations in the shutter arrangement formed by all of the shutter components, and thus to increased flexibility thereof. 
     In principle, it is conceivable to connect two directly adjacent shutter components by way of an integral hinge, in such a way that the shutter pivot axle can be formed by one of the shutter components itself or even be formed integrally with the two directly adjacent shutter components, for example forming a thin point between them. However, it is preferably provided that the shutter pivot axle is formed by a separate axle component, about which each of two directly adjacent shutter components is pivotable with respect to the other. This can facilitate the assembly of a plurality of mutually articulated shutter components to form a shutter component arrangement. 
     For example, the shutter components may be formed from extruded plastics material, whilst the shutter pivot axle may be formed by a stable, for example metal, component, for example a metal axle rod. 
     The separate axle component may simultaneously serve as a joining member for connecting two adjacent shutter components. 
     Preferably, the individual shutter components of a shutter component body comprise straps which face towards the pivot axle and which can be penetrated by the shutter pivot axle when finally assembled. So as to achieve a maximally stable articulated connection of two directly adjacent shutter components, the straps associated with a pivot axle are preferably arranged with mutual spacing in the axial direction in terms of the pivot axle, in such a way that a strap of one shutter component can come to be arranged between two straps of the adjacent shutter component. 
     If the straps which are associated with a first pivot axle of a shutter component are provided offset—with respect to the straps which are associated with a second pivot axle, different from the first, of the same shutter component—along the direction in which the pivot axles extend, in such a way that the straps associated with the first pivot axle are provided in intermediate space regions between the straps associated with the second pivot axle, a shutter component arrangement can be composed of substantially identical shutter components. Only the last or first shutter component in the direction of relative movement, which only has one adjacent shutter component, may be formed differently from the remaining shutter components as an end shutter component. 
     So as to require as little installation space as possible, whilst providing maximum flexibility of a shutter component arrangement, it is advantageous for the shutter components to be movable between the two stated relative positions along a relative movement trajectory such that the shutter pivot axle extends orthogonal to the relative movement trajectory. In this context, relative movement trajectory means for example the geometric location of a specific point of the first and last shutter components, in the direction of relative movement, during the movement of the shutter component arrangement between the positions thereof. In the aforementioned preferred construction, the relative movement trajectory is also the trajectory which is traversed by the pivot axles when the shutter component arrangement is adjusted between the positions thereof. 
     So as to be able, without requiring much installation space, to uncover an air passage opening which can be sealed or covered most effectively by a substantially planar arrangement of the mutually articulated shutter components, it is advantageous for the shutter components to be formed longer in the direction of the shutter pivot axle than in the direction of the relative movement trajectory. In this case, the shutter component arrangement is angled in a direction orthogonal to the pivot axle direction thereof, and this greatly facilitates stowage of the shutter component arrangement when the air passage opening is uncovered. 
     So as to guide the movement of the mutually articulated shutter components, in such a way that the shutter components reach one or more desired positions while they are being driven, it may be provided that the device frame comprises a flank, which laterally defines the air inlet opening and is substantially parallel to the relative movement trajectory, and in which a guide formation is provided, which cooperates with a guide counter-formation of the shutter components so as to guide the relative movement of the shutter components with respect to the device frame. If the shutter components are made very long in the direction of the pivot axles thereof, the precision of guidance can be increased further in that the device frame comprises two flanks, which are arranged mutually spaced opposite one another, each laterally define the air inlet opening and are substantially parallel to the relative movement trajectory, and in each of which a guide formation is provided, which in each case cooperates with a guide counter-formation of the shutter components so as to guide the relative movement of the shutter components with respect to the device frame. 
     In a particularly simple case, the guide counter-formation is provided on a longitudinal end of the shutter components or the guide counter-formations are provided on each longitudinal end of the shutter components. In this context, “longitudinal end” means an axial longitudinal end in terms of the pivot axle. In this context, the guide counter-formation may be a separate component which is mounted on the shutter component. However, it is particularly simple and therefore preferred for the longitudinal end of the shutter component itself to be formed as a guide counter-formation, for example by way of corresponding shaping at the relevant longitudinal end, and this is possible in a particularly simple manner if the shutter components are extruded or injection-moulded from thermoplastic plastics material. 
     The drive for the relative movement of the shutter components with respect to the device frame may comprise a rotatable drive part. This may be a drive wheel or a drive shaft. This rotatable drive part may be in, or be able to be brought into, a positive and/or non-positive engagement with at least one shutter component so as to transmit driving force to the shutter components. For example, driving force transmission may be provided by way of a positive engagement similar to the engagement of a gear wheel and a gear rod. 
     So as to interfere as little as possible with the flow of air through the air passage opening, it is preferably provided that the drive part is provided in an end region of the air passage opening in terms of the direction of relative movement of the shutter components. In this context, when finally assembled the drive part can be positioned in the geodetically higher end region of the air passage opening, in such a way that the drive moves the shutter components out of the air passage opening counter to gravity, but moves them into said opening with the assistance of gravity. A drive of this type always has to be powered when the air passage opening is supposed to be uncovered, since in this case a drive force countering gravity has to be exerted on the shutter components constantly. However, the drive can be switched off when the air passage opening is maximally covered, since in this case gravity maintains the position reached by the shutter components. 
     Equally, the drive may advantageously be placed at a geodetically lower end of the air passage opening. In this case, the conditions are reversed from what is described above. However, this last arrangement has the advantage that in this case gravity can be used to provide a failsafe function, since it acts on the shutter components in the direction to enlarge the flow cross-section of the air passage opening. However, this can only be achieved at the price of having to exert a drive moment on the shutter components constantly—to counter gravity, which cannot be switched off—when the cross-section is reduced to any extent. 
     However, the aforementioned failsafe action can also be achieved irrespective of gravity in that, in addition to the drive, it comprises a separate energy store, for example a spring energy store, which when released exerts a force on the shutter components in a direction enlarging the flow cross-section of the air passage opening. 
     A preferred spring energy store as the energy store may comprise a torsion spring, or else a tension or compression spring. 
     It is in principle conceivable to wind up the shutter component arrangement around a winding shaft, which may also be an aforementioned drive shaft. However, a relatively large compact construction space over the entire length of the shutter components may be necessary for this purpose, and is not always available in motor vehicles. 
     It is therefore preferred for a shutter component arrangement formed from a plurality of shutter components not to achieve a rolled-up state, in which one shutter component overlaps another, in any of the intended relative positions thereof, in such a way that the shutter component arrangement can merely be displaced, and can be deflected or angled during the displacement as a result of the provided pivot axles. In this context, for stowing the shutter component arrangement when the air passage opening is opened, a stowing space is required which is long and wide, but need only be approximately as thick as the shutter components themselves. A construction space of this type is often easier to find in motor vehicles than a stowing space for a shutter component arrangement winding. It is therefore preferred to form the shutter component arrangement as a planar component arrangement, which may optionally be angled multiple times, so as to be displaceable into and out of a functional space of a vehicle, in particular an engine space, in a translational manner with respect to the device frame. 
     Preferably, an electric motor which can be driven in two opposite rotational directions is used as a drive. 
    
    
     
       The present invention is described in greater detail in the following by way of the appended drawings, in which: 
         FIG. 1  is a perspective drawing of an embodiment according to the invention of a device for altering a flow cross-section of an air passage opening in a motor vehicle, showing the air passage opening fully closed, 
         FIG. 2  is a perspective sectional view of the embodiment of  FIG. 1 , 
         FIG. 3  is a schematic cross-sectional view through the embodiment of  FIGS. 1 and 2 , and 
         FIG. 4  is a schematic cross-sectional view corresponding to that of  FIG. 3  but with the air passage opening uncovered in part. 
     
    
    
     In  FIGS. 1 to 4 , an embodiment according to the invention of a device of the present application is denoted generally as  10 . 
     The device  10  comprises a device frame  12  having an air passage opening  16 , which is closed by a shutter component arrangement  14  in  FIGS. 1 to 3  and is opened in part in  FIG. 4 . 
     The air passage opening  16  may be defined laterally by flanks  18 , in which, as is shown in  FIG. 2 , a guide formation in the form of a guide rail  20  may be provided for guiding an opening and closing movement of the shutter component arrangement  14 . 
     The rails  20  may form a guide groove in which longitudinal ends of the substantially identical shutter components  22  can engage. 
     When they are finally assembled, the longest dimension of the shutter components  22  preferably extends in the transverse direction of the vehicle, and they are preferably mutually articulated by way of pivot axles  24 . 
     The device frame  12  may comprise air guidance surfaces  26  and  28 , which define the air passage opening  16  from above and from below. Between the air guidance surfaces  26  and  28 , a further air guidance surface  30  may be provided, so as to deflect the air flowing in through the air passage opening  16  in a desired direction. 
     The air guidance surface  30  may comprise an opening  32  which can be penetrated by the shutter component arrangement  14 . 
     In the example shown, a drive shaft  34  is provided at the geodetically upper end of the air passage opening  16 , and can transmit driving force to the shutter components  22  of the shutter component arrangement  14  via force transmission means (not shown). 
     In the example shown, the pivot axle components  24  are formed by metal rods, which may be enclosed by straps  36  and  38 , which may be formed integrally with a shutter component  22  at different ends of the width thereof. In this context, the straps  36  are associated with the same first pivot axle  24  and the straps  38  are associated with the same other (second) pivot axle  24 . 
     The straps  36  and  38  are preferably of the same length in the axial direction in terms of the pivot axles  24 , and are arranged with a mutual axial spacing which corresponds to the length of a strap, in such a way that the straps  36  and  38  of two adjacent shutter components  22 , which engage around the same pivot axle  24 , can be arranged mutually interlocked. This saves space in the arrangement. 
     The drive shaft  34  is coupled to a source of driving force (not shown in  FIGS. 1 to 4 ), for example an electric motor which can be driven in opposite rotational directions. 
     This drive can be actuated irrespective of operating parameters of the vehicle to which the device shown in  FIGS. 1 to 4  is attached. 
     If a unit, such as a cooler or other heat exchanger of the vehicle, which is positioned downstream from the drive frame  12  in the flow direction D, has a cooling requirement on the basis on the present vehicle operating data, the drive  34  is actuated so as to move the shutter component arrangement  14  out of the air passage opening  16  at least in part. 
     In this context, it is possible to bring about any desired partial opening situation, in that the drive is stopped after reaching the partial opening position of the shutter component arrangement  14  or continues to be supplied with power in such a way that it counters and compensates the gravity acting on the shutter components  22 . 
     As is shown in  FIG. 4 , the shutter component arrangement  14  is preferably not wound up on the drive shaft  34  or any other winding shaft; instead, so as to save installation space, the shutter component arrangement  14  is merely displaced and angled, in such a way that it can be concealed and stowed for example under an air guidance surface, in this case for example the air guidance surface  26 . 
     Thus, even when the air passage opening  16  is open in part or even completely, only installation space of approximately the same thickness as the shutter components  22  themselves is required for the shutter component arrangement  14 , and this space is easier to find in a vehicle functional space, such as a vehicle engine space, than a radially protruding stowage space for winding up the shutter component arrangement  14 . 
     Alternatively, the drive shaft  34  may also be provided as a drive shaft  34 ′ in the geodetically lower end region of the air passage opening  16 . 
     However, in the example shown in  FIGS. 1 to 4 , the drive shaft  34  is advantageously concealed at the geodetically upper end of the air passage opening  16  downstream from the air guide surface  26 , in such a way that it interferes with an airflow through the air passage opening  16  less than the alternative drive shaft  34 ′. 
     However, driving the shutter component arrangement  14  by way of the lower, alternative drive shaft  34 ′ would have the advantage that gravity would assist in an opening movement of the shutter component arrangement  14 , in such a way that opening or release of the air passage opening  16  can be ensured even if the drive fails. 
     A relative movement trajectory, which is traversed by the shutter component arrangement  14  during the movement thereof to close the air passage opening  16  completely when the air passage opening  16  is incompletely opened, is shown in  FIG. 4  and denoted as R.