Abstract:
A ventilation flap arrangement, in particular for venting a motor vehicle interior, as well as a method for producing a ventilation flap arrangement of this type, which has the method steps of providing one or more flexible cover flaps, providing a frame for holding the cover flaps, wherein the frame for a cover flap has a receiving groove formed by two side cheeks, inserting the cover flap between the two side cheeks of the receiving groove of the frame and non-detachable connection of the cover flap to the receiving groove by embossing.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a ventilation flap arrangement, in particular for venting a motor vehicle interior, with cover flaps and a frame for holding the cover flaps. Furthermore, the invention relates to a method for producing a ventilation flap arrangement of this type. 
       BACKGROUND OF THE INVENTION 
       [0002]    A ventilation flap arrangement with an inner frame, an outer housing and cover flaps is known from DE 40 02 052 A1, the cover flaps consisting of very soft, flexible material being clamped between the inner frame and the outer housing. A ventilation flap arrangement of this type is produced in a complex assembly process with many individual components. 
         [0003]    It is furthermore known from DE 195 48 551 A1 that cover flaps are produced in one piece with a frame by means of conventional two-component injection moulding methods. These production methods require expensive tools and optionally injection moulding machines adapted thereto. The production of a ventilation flap arrangement by the multi-component injection moulding method is expensive. 
         [0004]    It is also known from DE 195 48 551 A1 and from EP 0 645 268 A1 to fix the cover flaps by a clamping strip moulded onto the frame or by lugs attached thereon. Cover flaps fixed in this manner may be problematical with regard to a sealing abutment on the frame of a ventilation flap arrangement. 
       SUMMARY OF THE INVENTION 
       [0005]    The invention is based on the object of providing a ventilation flap arrangement and a method for producing a ventilation flap arrangement of this type with regard to an economical fastening of cover flaps to a frame in such a way that the number of components is reduced, assembly is simplified and the tightness of a ventilation flap arrangement is ensured. 
         [0006]    This object is achieved from a product point of view by a ventilation flap arrangement according to the invention comprising a flexible cover flap being non-detachably connected to a receiving groove of a frame formed by two side cheeks by embossing. A venting flap arrangement of this type is easy to assemble and has a reduced number of components; in particular a separate clamping frame is no longer provided. As a result, tool investment costs and machine occupation times are reduced. At least one side cheek projects with an embossed projection into at least one opening configured close to the edge on the cover flap, so the non-detachable connection of the cover flap to the receiving groove can be implemented by a positive fit in a few small island-shaped joint regions. The cover flaps are produced from soft elastic material in order to guarantee a sealing abutment of the cover flaps on the frame. The cover flaps may have at least one notch to receive a reinforcement rib of a receiving groove corresponding with the notch. The frame has support ribs, on which the side cheeks of the receiving grooves are attached. The support ribs are also used for the sealing abutment of a cover flap attached on an adjacent support rib. The receiving grooves may be configured in such a way that they taper toward a groove base, so the insertion of the cover flaps into the receiving grooves is facilitated. An assembly shoulder on the frame of the ventilation flap arrangement allows a defined attachment of the ventilation flap arrangement in a venting channel. 
         [0007]    A method for producing a ventilation flap arrangement comprises, apart from providing one or more flexible cover flaps and a frame with a receiving groove formed by two side cheeks, the insertion of the cover flap between the two side cheeks into the sealing groove as well as the non-detachable connection of the cover flap to the receiving groove by embossing. A method of this type has few manufacturing steps. The forming of the at least one side cheek with an embossing die so an embossed projection of the at least one side cheek projects into at least one opening configured close to the edge on the cover flap or at least holds the cover flap in a clamping manner, can be carried out in an automated and economical manner. By producing the embossed projections of the side cheeks by a embossing die pair acting thereon on both sides, the maximum forming of the side cheeks is reduced. Acting on the region to be embossed of the side cheek with temperatures in the range between a dimensional stability temperature and a melting temperature of a material to be embossed and/or ultrasound increases the formability of the material, from which the side cheeks are produced. 
         [0008]    Further advantageous configurations of the invention, features and details of same are described in more detail in the following description with the aid of the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIGS. 1 and 2  show cross-sections of a ventilation flap arrangement in different embodiments, 
           [0010]      FIGS. 3 and 4  show plan views of cover flaps without and with notches, 
           [0011]      FIGS. 5 and 6  show enlarged detail cross-sections of cover flaps during their attachment to a frame in a first intermediate production step, 
           [0012]      FIGS. 7 and 8  show cross-sections analogous to  FIGS. 5 and 6  in a subsequent intermediate production step with a one-sided embossing process in various embossing directions, 
           [0013]      FIG. 9  shows a cross-section analogous to  FIG. 8  with a one-sided embossing process with a formed side cheek of a receiving groove, 
           [0014]      FIG. 10 to 12  show cross-sections that are increased again of one-sided embossing processes with formed side cheeks and 
           [0015]      FIG. 13  shows a cross-section analogous to  FIGS. 7 and 8  with a two-sided embossing process. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    The ventilation flap arrangements shown in  FIGS. 1 and 2  have a frame  1 ,  1   a  with a plurality of support ribs  2  and a plurality of receiving grooves  3  to hold cover flaps  4 , each receiving groove  3  being formed by two side cheeks  5 , which are moulded in one piece on the frame  1 ,  1   a.  For easier introduction of the cover flap  4  into the receiving groove  3 , the side cheeks  5  may in each case have an insertion bevel oriented toward the receiving groove  3 . The receiving groove  3  may comprise a plurality of reinforcement ribs  15  (cf.  FIG. 6 ), which are moulded in one piece on the support rib  2  between the two side cheeks  5  in a groove base  6 . The reinforcement ribs  15  are used to stabilise the receiving groove  3  formed by the side cheeks  5 , so a possible distortion of the side cheeks  5  and therefore a shape deviation of the receiving groove  3  as a result of a previous production method, in particular an injection moulding process with a subsequent cooling process, are reduced. The frame  1 ,  1   a  has an assembly shoulder  7  for attaching the ventilation arrangement in a venting channel, in particular of a motor vehicle. A seal  9  may be provided in the assembly shoulder  7  for air-tight sealing of a vehicle interior  8  with respect to the venting channel. To attach the ventilation flap arrangement in the venting channel to vent a vehicle interior  8 , the ventilation flap arrangement is inserted along an assembly direction  10 ,  10   a  into the venting channel. An assembly of the ventilation flap arrangement from an opening of the venting channel opposing the vehicle interior  8  in the direction of the motor vehicle interior  8  takes place in the assembly direction  10  and an assembly of the ventilation flap arrangement from the motor vehicle interior  8  into the venting channel takes place in the assembly direction  10   a.  The assembly shoulder  7  is used for a defined positioning of the ventilation flap arrangement in the venting channel. The cover flaps  4  produced from flexible material are, in each case, held by a receiving groove  3 , which is formed by two side cheeks  5  provided on a support rib  2 , the cover flaps  4  in the rest state, i.e. there is no venting, resting in a sealing manner on a support rib  2  adjacent to the support rib  2  being used to hold the cover flap  4 . This ensures that the ventilation flap arrangement allows an escape of air from the vehicle interior  8  into the venting channel in the manner of a check valve and simultaneously prevents air flowing from the venting channel into the vehicle interior  8 . 
         [0017]    A flexible cover flap  4  shown in  FIG. 3  has an extended rectangular shape and has a plurality of openings  12  arranged close to its one longitudinal edge  11 , as well as a respective side insertion bevel  13  on one end of the longitudinal edge  11  for easier insertion of the cover flap  4  into a receiving groove, not shown. The openings  12  are round, but they may also be rectangular, square or configured as slots. The significance of the openings  12  will be described below. The flexible cover flap  4  may also be designed without openings  12  and without insertion bevels  13 . 
         [0018]      FIG. 4  shows a flexible cover flap  4  which is similar to the one shown in  FIG. 3  and comprises additional notches  14  which have a rectangular, in particular square shape and are used to receive reinforcement ribs  15  (cf.  FIG. 6 ) of a receiving groove, not shown, during an assembly process of the cover flaps  4  on the frame  1 ,  1   a.  An outer contour of the reinforcement rib  15  corresponds with the shape of the notch  14 . 
         [0019]      FIG. 5  shows the attachment of a cover flap  4  according to  FIG. 3  on a frame  1  in a first production step. For this purpose, the cover flap  4  is inserted in a receiving groove  3  which is formed by two side cheeks  5  and tapers toward a groove base  6 , so the insertion of the cover flap  4  into the receiving groove  3  is additionally facilitated. 
         [0020]      FIG. 6  shows the attachment of a cover flap  4  according to  FIG. 4  on a frame  1  in a first production step. The cover flap  4  is also inserted here into a receiving groove  4  formed by two side cheeks  5 , the side cheeks  5  of the receiving groove  3  being arranged substantially parallel to one another. The cover flaps  4  are positioned in the receiving groove  3  by the receiving of reinforcement ribs  15  of the receiving groove  3  in notches of the cover flap  4 . 
         [0021]      FIGS. 7 and 8  show embodiments of a one-sided embossing process as a production step following the first production step shown in  FIG. 5  or  6  for the non-detachable connection of a cover flap  4  to a receiving groove  3  on a support rib  2  by an embossing die  16 ,  16   a.  Depending on an assembly direction  10 ,  10   a,  an embossing direction  17 ,  17   a,  along which the embossing die  16 ,  16   a  acts against a side cheek  5  of the receiving groove  3 , varies. The embossing direction  17 ,  17   a  substantially corresponds to the assembly direction  10 ,  10   a.  The geometry of the embossing die  16 ,  16   a  is adapted to the respective shape of the support ribs  2  of a frame  1 ,  1   a  of the receiving groove  3  and the cover flap  4  and a material to be embossed. The embossing direction  17 ,  17   a  may also be selected in accordance with a desired visibility of an embossing. 
         [0022]    A non-detachable connection of a cover flap  4  to a receiving groove  3 , shown in  FIGS. 9 and 10 , is produced by one-sided embossing with an embossing die head  18  of an embossing die  16  along an embossing direction  17 . As a result of the embossing process, a side cheek  5  of the receiving groove  3  is formed with the embossing die  16  in such a way that an embossed projection  19  of the side cheek  5  is formed. Once the embossing process has been completed, an embossed projection  19  projects into each opening  12  of the cover flap  4 . The formed side cheek  5 , after the embossing process, has a restricted area  20 , which corresponds with an embossed projection  19  and has been produced by the action of the embossing die head  18 . The embossed projection  19  and the restricted area  20  have a round cross-sectional face corresponding to the embossing die head  18 . The cross-sectional face of the embossed projection  19  and the restricted area  20  may, however, also be rectangular or square, the shape of the embossed projection  19  corresponding with the shape of the opening  12 . 
         [0023]      FIG. 11  shows a non-detachable connection, shown enlarged, of a cover flap  4  with receiving groove  3 , a one-sided embossing process being carried out with a substantially conical head  18 ′ of an embossing die. The cover flap used has no openings, so, as a result of the embossing process, a side cheek  5  of the receiving groove  3  is formed with the embossing die in such a way that an embossed projection  19  of the side cheek  5  is formed. The cover flap is thus pierced by a tapering end of the conical embossing head with the formation of a perforation  21 , the embossed projection  19  in the perforation  21  being formed by the subsequent pressing of material. The embossed projection  19  of one side cheek  5  may be connected to the other side cheek  5  of the receiving groove  3 . 
         [0024]      FIG. 12  also shows a non-detachable connection, shown enlarged, of a cover flap  4 , which has no openings, to a receiving groove  3 . As a result of an embossing process, a side cheek  5  of the receiving groove  3  is formed with an embossing die in such a way that an embossed projection  19  of the side cheek  5  projects into the receiving groove  3  receiving the cover flap  4 . As a result, the cover flap  4  is clamped in the receiving groove  3 . 
         [0025]    A two-sided embossing process analogous to the one-sided embossing process shown in  FIGS. 7 and 8  is made possible with an embossing die pair  16 ,  16   a  shown in  FIG. 13 . In this case, the embossing die pair  16 ,  16   a  acts on the two side cheeks  5  of a receiving groove  3  of a ventilation flap arrangement with the formation of a respective embossed projection of the two side cheeks  5 . The side cheek  5  is formed less to produce the embossed projection in the two-sided embossing process than to form an embossed projection in a one-sided embossing process. Each embossing die  16 ,  16   a  acts in the two-sided embossing process along an embossing direction  17 ,  17   a,  the embossing directions  17 ,  17   a  having various orientations, which intersect in a plane spanned by a cover flap  4  at a respective opening  12 . 
         [0026]    The frame  1  that has a plurality of support ribs  2  each with two side cheeks  5  attached in one piece thereon is made of plastics material, in particular by the injection moulding method. The cover flap  4  consists of a soft elastic material and is in particular produced by punching. An embossing process for a non-detachable connection of the cover flap  4  to a receiving groove  3 , which is formed by two side cheeks  5 , may take place by cold embossing at room temperature with a suitable selection of material. A possible material is a plastics material available under the name “Baroplastic” based on a mixture of a comparatively rigid polystyrene and relatively soft polybutyl acrylate. This material can already be shaped merely by pressure at room temperature. 
         [0027]    A region of the side cheek  5  to be embossed can also be heated to a temperature in the range between a dimensional stability temperature and a melting temperature of a material to be embossed in order to achieve better formability of the side cheek  5 . A preferably used material is PP 6.2 recyclate, the dimensional stability temperature of which is 86° C. and the melting temperature of which is 163° C. To reach these temperatures, an embossing die  14 ,  14   a  heated to 280° C. to 350° C. may be used. Alternatively, the region to be embossed of the side cheek  5  may also be heated by radiation heat emitted by a heating element heated to 400° C. to 550° C. The formability of the side cheek  5  can also be increased in that the region to be embossed is acted upon by ultrasound. A frequency range preferred for this, as a function of a sonotrode used, is 20 kHz to 40 kHz. 
         [0028]    Improved stability of the embossing connection can be achieved in that an adhesive connection is provided between an embossed projection of a first side cheek as a result of the action of temperature and/or ultrasound and a second side cheek arranged opposing the first side cheek. The plastics materials acrylonitrile butadiene styrene (ABS), polyamide 6 (PA 6), polypropylene (PP), polyphenylene sulphide (PPS), polycarbonate (PC) and polystyrene (PS) have proven particularly suitable for an embossing process at increased temperature and/or upon the action of ultrasound. The plastics materials acrylonitrile butadiene styrene with polycarbonate blend (ABS-PCB), polyoxymethylene (POM), polyamide 6.6 (PA 6.6) and polybutylene terephthalate (PBT) are well suited to temperature-assisted embossing but only to a limited extent for embossing with ultrasound.