Abstract:
The invention relates to a drum-type valve ( 1; 101; 201; 301; 301 ′) comprising: a partial cylindrical surface forming a first area ( 2; 102; 302 ); two circular segment surfaces each forming a second area ( 3; 103; 303 ), and; an outer encircling edge ( 4; 104; 304 ), which is disposed essentially in two planes, outwardly projects, and which is rests against correspondingly formed contact surfaces, whereby the drum-type valve ( 1; 101; 201; 301; 301 ′) has at least one second edge ( 5; 105; 305 ).

Description:
BACKGROUND 
     The invention relates to a drum flap, in particular for distributing air in a motor vehicle ventilation system. 
     Drum flaps which have a rim running around the outside in order to increase the stability and to form a seal are known. Drum flaps of this type still leave something to be desired in terms of their leaktightness. 
     An air flap with a surrounding rim is also known from DE 100 53 814 A1, but this air flap deviates from a cylindrical shape. 
     DE 198 19 280 A1 has disclosed an air distribution apparatus with drum flap which comprises a housing with a cylindrical wall including at least two air passage openings, a flap mounted pivotably with respect to an axis of rotation and a generally cylindrical closure wall, which is mounted movably in relation to a flap body comprising two side parts, in a direction which is approximately radial with respect to the axis of rotation of the flap, with this movement being effected by adjustment means which are synchronized with the rotation of the flap, with the result that the closure wall can be moved away from the wall when the flap is in an opening position, and with the result that the closure wall can be moved toward the wall of the housing when said flap is in a closure position. An air distribution apparatus of this type has a large number of components and a complicated construction, making it too expensive to produce. 
     It is an object of the invention to provide an improved drum flap. 
     This object is achieved by a drum flap described herein. 
     SUMMARY 
     The invention provides a drum flap having a curved surface, which forms a first region, and two circle-segment surfaces, which each form a second region, and having a rim which runs around the outside, is arranged substantially in two planes, in which the pivot axis also lies, projects outward and serves to bear against correspondingly designed bearing surfaces, which drum flap has at least a second rim. This second rim serves in particular to improve the sealing, so that one drum flap can be used to control a plurality of, for example four, air passages, and when the rims bear against corresponding stops, there is no undesirable cross-flow on the part of the air. The curved surface is designed, for example, as a part-cylinder surface or a part-sphere surface. 
     According to a first embodiment, the second rim is provided in the first region and preferably also the second region of the drum flap. The second rim is preferably arranged in a plane in which the pivot axis also lies and projects outward, the plane in which the second rim lies being arranged in an angle between the two other planes in which the first rim lies. In this case, it is preferable for at least one opening to be provided in at least one segment of the first and/or second region, the corresponding segment being delimited by two adjacent rims, so that it is possible to reliably prevent a cross-flow of air. To prevent a cross-flow of the air in the region of the pivot axis and to increase the stability of the drum flap, it is preferable for a circular region with a thickness designed to match that of the rims to be provided in the region of the pivot axis. 
     According to a second embodiment, the second rim runs substantially around a third region, which directly or indirectly, separated by an intermediate region, adjoins the lateral surface in the region of the first rim. This third region is preferably approximately rectangular in form, although it may also take a different form, surrounded by a second rim, which is used in particular for sealing purposes, so that a cross-flow can be prevented. 
     It is preferable for the planes in which the third region and the intermediate region lie to be arranged at an angle not equal to 180° with respect to one another. In this context, it is preferable to use an angle of less than 180° to 120 °. 
     The drum flap is preferably used as an air distributor flap and/or as a temperature mixing flap in a motor vehicle air-conditioning system, the drum flap according to the first embodiment preferably serving as an air distributor flap, and the drum flap according to the second embodiment preferably serving as a temperature mixing flap. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the text which follows, the invention is explained in detail on the basis of four exemplary embodiments and with reference to the drawings, in which: 
         FIG. 1  shows a perspective view of a drum flap in accordance with the first exemplary embodiment, 
         FIG. 2  shows the drum flap from  FIG. 1  from a different perspective, 
         FIG. 3  shows a side view of the drum flap from  FIG. 1  in order to illustrate its function in a first position, 
         FIG. 4  shows a side view of the drum flap from  FIG. 1  is a second position, 
         FIG. 5  shows a perspective view of a drum flap in accordance with the second exemplary embodiment, 
         FIG. 6  shows a perspective view of a drum flap in accordance with the third exemplary embodiment, 
         FIG. 7  shows the drum flap from  FIG. 6  from a different perspective, 
         FIG. 8  shows a detail view of region E from  FIG. 7 , 
         FIG. 9  shows the drum flap from  FIG. 6  from a different perspective, 
         FIG. 10  shows a detail view of region D from  FIG. 9 , 
         FIG. 11  shows a side view of the drum flap from  FIG. 6  with two detail views, 
         FIG. 12   a - c  show three views of a motor vehicle air-conditioning system with the drum flap from  FIG. 6  in different positions, 
         FIG. 13  shows a perspective view of a second motor vehicle air-conditioning system with two drum flaps, 
         FIG. 14  shows the air-conditioning system from  FIG. 13  from a different perspective, 
         FIG. 15   a - f  show side views of the air-conditioning system from  FIG. 13  with various flap positions, and 
         FIG. 16  shows the drum flap in accordance with the fourth exemplary embodiment used in the air-conditioning system from  FIG. 13  in the form of a perspective illustration. 
     
    
    
     DETAILED DESCRIPTION 
     A drum flap  1  as used in particular in a motor vehicle air-conditioning system has a first region  2 , which is formed by a subregion of a cylinder, and two second regions  3 , which are formed by the circle segments of the side faces of the corresponding cylinder. The transition region is rounded in form. As in conventional drum flaps, a rim  4 , protruding perpendicularly outward, runs around the edge of the first and second regions  2  and  3  respectively. This rim  4  forms a bearing surface which at the same time, by interacting with an associated second bearing surface formed on the air guidance housing of the air-conditioning system, also has a sealing function. 
     Next to the first rim  4  there is a second rim  5 , which like the first rim  4  runs in a plane in which the pivot axis of the drum flap  1  also lies. In this case, the second rim  5  divides the first and second regions  2  and  3  in each case into two segments  2 ′ and  2 ″ or  3 ′ and  3 ″, respectively. According to the first exemplary embodiment, an opening (side opening) is provided in each of the segments  3 ″ of the second region  3 , whereas the segments  2 ′,  2 ″ and  3 ′ are formed without openings. 
     To mount the drum flap  1 , two bearing journals  6 , which in the installed state are mounted in bearings are provided in the pivot axis. A circular region  7 , which is part of the first and second rims  4  and  5  and also has a sealing function, is provided around the bearing journals  6 . 
       FIGS. 3 and 4  illustrate two positions of the drum flap  1  which is installed in an air-conditioning system, is used as an air distributor flap and serves to control the distribution of air between three air passages, namely the defrosting air passage, indicated in  FIGS. 3 and 4  by “defrost”, the footwell air passage, indicated in  FIGS. 3 and 4 , by “footwell”, and the ventilation air passage, indicated in  FIGS. 3 and 4  by “ventilation”. The airflow is represented by arrows. 
       FIG. 3  shows a flap position in which a large amount of air is being fed to the windshield for defrosting purposes and some air is being fed to the vehicle interior compartment via the side opening. The footwell air passage is closed. 
     In the flap position shown in  FIG. 4 , the defrosting air passage is closed, some air is passing into the footwell air passage via the side opening and the ventilation air passage is fully open. 
     According to a second exemplary embodiment, which is illustrated in  FIG. 5 , an opening (front opening) is also provided in segment  2 ″. Other arrangements of openings, for example an offset arrangement of side and front openings in individual segments, are possible. In this exemplary embodiment too, there are two rims  4  and  5  which are used for sealing purposes. 
     A drum flap  101  in accordance with the third exemplary embodiment is illustrated in  FIGS. 6 to 11 . In this case, the drum flap  101  has a first region  102 , which is formed by a subregion of a cylinder, and two second regions  103 , which are formed by circle segments of the side faces of the corresponding cylinder. The transition region is rounded in form. As in conventional drum flaps, a rim  104 , protruding perpendicularly outward, runs around the edge of the first and second regions  102  and  103 , respectively. This rim  104  forms a bearing surface which, in the same way as the rim  4  of the first and second exemplary embodiments, by interacting with an associated second bearing surface formed on the air guidance housing of the air-conditioning system, at the same time also has a sealing function. 
     As can be seen in particular from  FIG. 8 , the first region  102  is adjoined by a third region  110 , which is rectangular in form and is delimited on one side by the corresponding rim  104  and on the other three sides by a second rim  105 . The transition between the rims  104  and  105  is formed in sealing fashion, so that in principle the two regions  102  and  110  are each completely surrounded by a delimiting rim and are therefore sealed off independently of one another when the corresponding rim bears against a bearing surface. 
       FIGS. 12   a  to  12   c  illustrate a motor vehicle air-conditioning system  220  having a fan  221 , an evaporator  222 , a radiator  223 , a drum flap  201 , which corresponds to the drum flap of the third exemplary embodiment, and a mixing space  224 . In this case, the drum flap  201  in  FIG. 12   a  blocks off the passage of air through the radiator  223 , so that the air fed to the vehicle interior compartment is cooled to its maximum extent. 
       FIG. 12   b  illustrates an intermediate position of the drum flap  201 , while  FIG. 12   c  illustrates a position in which all of the air is passed through the radiator  223  and therefore heated to the maximum extent. As can be seen in  FIGS. 12   a  to  12   c , in the limit positions the drum flap  201  bears against stops  225  which are formed on the air guidance housing of the air-conditioning system  220 . The rims  205  and  210  ensure that no air passes into the mixing space  224  in the closed position. 
       FIGS. 13 to 15   f  show a second motor vehicle air-conditioning system  320 , having a fan  321 , an evaporator  322 , a radiator  323 , a first drum flap  301 , which serves as a distributor flap and corresponds to the drum flap of the first exemplary embodiment, and a second drum flap  301 ′, which serves as a temperature mixing flap, is illustrated in more detail in  FIG. 16  and is described in more detail below, as well as a mixing space  224 . 
     The first drum flap  301  is used to distribute the air between a plurality of air passages, namely the air passage  331 , which leads to the center nozzle, the air passage  332 , which leads to the side nozzle, the air passage  333 , which leads to the footwell, and the air passage  334 , which is used to defrost the windshield. 
     The second drum flap  301 ′, which as seen in the direction of airflow is arranged upstream of the first drum flap  301 , has a first region  302 , which is formed by a subregion of a cylinder, and two second regions  303 , which are formed by the circle segments of the side faces of the corresponding cylinder. The transition region is rounded in form. As in the drum flaps  1  and  101  described above, a rim  304 , protruding perpendicularly outward, runs around the edge of the first and second regions  302  and  303 . This rim  304  forms a bearing surface which, like the rims of the exemplary embodiments described above, by interacting with an associated second bearing surface formed on the air guidance housing of the air-conditioning system, at the same time also has a sealing function. 
     As can be seen from  FIG. 16 , an intermediate region  340  adjoins the first region  302  and is in turn adjoined by a third region  310  which is rectangular in form. In this case, the third region  310  is delimited by a second rim  305  on all four sides. In the present case, the intermediate region  340  and the third region  310  are arranged at an angle of approx. 140° with respect to one another, to enable complete sealing of the flow path of the air through the radiator  323  to be avoided (cf. for example  FIG. 15   c ), since the rims  304  and  305  bear tightly against bearing surfaces formed by the air guidance housing. The width of the intermediate region  340  approximately corresponds to the thickness of the radiator  323 . 
     According to the present exemplary embodiment, the intermediate region  340  and the third region  310  are arranged at an angle not equal to 180° with respect to one another, although it is also possible for them both to be arranged in one plane. 
     The fan  321  draws in fresh air or recirculated air, as illustrated by an arrow in the top right of  FIG. 14 . This air is passed through the evaporator  322  and, depending on the position of the second drum flap  301 ′, bypasses the radiator  323  and/or is passed through the latter. The air is mixed in the mixing space  324  if the second drum flap  301 ′ splits the air stream. Then, depending on the position of the first drum flap  301 , the air is distributed between the air passages  331 ,  332 ,  333  and  334  and is fed to the vehicle interior compartment. 
     Various positions of the two drum flaps  301  and  301 ′ are illustrated in  FIG. 15   a  to  15   f .  FIG. 15   a  shows the “maximum heating” position of the second drum flap  301 ′, in which the warm air is fed to the windshield in order to defrost it and to the side nozzle, i.e. the air passages  332  and  334  are opened up while the air passages  331  and  333  are tightly closed. 
       FIG. 15   b  shows a mix position of the second drum flap  301 ′, so that the warm and cold air is mixed in the mixing space  324 . The position of the first drum flap  301  corresponds to that shown in  FIG. 15   a , so that the air, the temperature of which has been controlled according to the opening of the second drum flap  301 ′, is fed to the windshield in order to defrost the latter and to the side nozzle. According to  FIG. 15   c , cold air is fed to the windshield in order to defrost the latter and to the side nozzle, since the second drum flap  301 ′, on account of its configuration, is tightly blocking the path through the radiator  323 , specifically both from the front and from the rear. 
       FIG. 15   d  once again shows the “maximum heating” position of the second drum flap  301 ′(cf.  FIG. 15   a ), but with the first drum flap  301  pivoted in such a manner that the air is fed to the vehicle interior compartment via the air passages  331 ,  332  and  333  while the air passage  334  is closed. The precision setting of the air distribution between these three air passages can be effected in situ by means of the corresponding nozzles.  FIG. 15   e  shows a corresponding air distribution for maximum cooled air and  FIG. 15   f  shows the corresponding air distribution for temperature-controlled air. 
     On account of their correspondingly configured rims, the drum flaps of all the exemplary embodiments allow good sealing between the drum flap and the corresponding bearing surfaces, so that optimized temperature control of the air is possible. 
     LIST OF DESIGNATIONS 
     
         
           1 ,  101 ,  201 ,  301 ,  301 ′ drum flap 
           2 ,  102 ,  302  first region 
           2 ′,  2 ″ segment 
           3 ,  103 ,  303  second region 
           3 ′,  3 ″ segment 
           4 ,  104 ,  304  first rim 
           5 ,  105 ,  305  second rim 
           6  bearing journal 
           7  circular region 
           110 ,  310  third region 
           220 ,  320  air-conditioning system 
           221 ,  321  fan 
           222 ,  322  evaporator 
           223 ,  323  radiator 
           224 ,  324  mixing space 
           225  bearing surface 
           331 ,  332 ,  333 ,  334  air passage 
           340  intermediate region