Abstract:
Ventilating device ( 1 ) comprising a casing ( 6 ) intended to channel at least one air flow ( 3 ) created by a blower wheel ( 5 ), the said casing ( 6 ) delimites a main air channel ( 7 ) in which a main air flow ( 3   a ) circulates and a secondary air channel ( 8 ) intended to bring towards a motor ( 4 ) a secondary air flow ( 3   b ) in order to cool the motor ( 4 ), the said secondary air channel ( 8 ) comprising a inlet ( 11 ) arranged in a main channel wall ( 7   c ) and a outlet arranged in a plan containing a casing end by which the wheel ( 5 ) is introduced, the said secondary channel ( 8 ) further comprising a means intended to change at least twice the direction of the secondary air flow ( 3   b ) when the secondary air flow ( 3   b ) passes through the secondary air channel ( 8 ).

Description:
TECHNICAL FIELD OF THE INVENTION  
       [0001]    The present invention relates to a ventilation device that creates an air flow for supplying an air conditioning and/or heating system. The present invention makes it possible to cool an electric motor by means of an air flow. The present invention relates more particularly to a ventilation device for a motor vehicle. 
       BACKGROUND OF THE INVENTION  
       [0002]    To ventilate, and to deliver hot or cold air into, the cabin of a motor vehicle, a ventilation device is connected to an air conditioning and/or heating system to supply air to the motor vehicle cabin. As illustrated in  FIGS. 1 ,  1   b , and  1   c , the ventilation device  1  comprises a casing  6 , an electric motor  4 , and a blower impeller  5 , the latter having vanes  5   a  and a hub  5   b  and being driven by this motor. The casing  6 , which is usually shaped like a spiral cylinder, comprises a peripheral wall  6   a  and two open ends  6   b ,  6   c , the first open end  6   b  acting as the air inlet of the ventilation device  1  and the second open end  6   c  allowing the blower impeller  5  to be inserted into the internal volume of the casing  6 . Also, this casing  6  defines a main air channel  7  carrying the air flow produced by the blower impeller to the air-conditioning and/or heating system. This blower impeller is connected to the electric motor  4  and is therefore held in the casing  6  by an attachment, in the second opening  6   c , of a motor cradle  9  casing the electric motor  4 . In this way, part of said motor housed in the bowl  5   c  of the impeller  5  is inside the casing  6 , while the other part of the motor  4  is inside the motor cradle  9 . The blower impeller  5  is driven by the electric motor  4 , so that this air flow is produced by the operation of said motor. Thus, whenever the air conditioning and/or heating system is on, the electric motor  4  is running and generating heat. It is therefore vital to cool this motor to prevent it being damaged by prolonged use of the air conditioning and/or heating system. 
         [0003]    To cool the electric motor when it is running, one approach has been to divert some of the air flow generated by the blower impeller for the air conditioning and/or heating system, so that the motor is cooled by an air flow over it. To divert some of the air flow, a secondary channel  8  is added. This secondary channel  8  comprises an air flow inlet  11  and an air flow outlet  12 . The air flow inlet  11  is located in a side wall  7   c  of the main channel  7 . The air flow outlet  12  corresponds to the air flow inlet of a duct  9   a  formed in the motor cradle  9 . This duct is also shaped in such a way that it takes the air flow coming from the secondary channel and conveys it to the electric motor. 
         [0004]    However, this method of cooling the electric motor has one great drawback in that the diverted air flow may be damp. This dampness may be due to weather conditions (rain, humid external air) or to water being forced in, for example during pressure-washing of the engine compartment or when the vehicle&#39;s bodywork is being washed. On these occasions, water may get into the ventilation device through its air inlet. The electric motor may therefore come into contact with water, exposing it to a serious risk of damage. 
         [0005]    Since manufacturers&#39; standards are becoming more and more demanding in the automotive field, for reasons of safety and durability, it is desirable to reduce the presence of water in the air flow used to cool the electric motor. 
         [0006]    The problem is therefore how to reduce the amount of water transported by the air flow through the secondary channel and thus avoid having the electric motor coming into contact with a liquid or with over-humid air when it is running. 
         [0007]    The applicant&#39;s invention solves this problem with a ventilation device comprising a casing suitable for channeling at least one air flow set up by a blower impeller, which casing defines a main air channel carrying a main air flow, and a secondary air channel designed to carry a secondary air flow to a motor in order to cool it, said secondary channel having on the one hand an inlet located in a wall of the main channel and on the other hand an outlet located in a plane containing an end of the casing through which the impeller is inserted; which device is characterized in that the secondary channel has a means designed to cause the secondary air flow to change direction at least twice as it travels along said secondary channel. 
         [0008]    The provision of a means for diverting the air flow into the secondary channel prevents water reaching the outlet, because the various changes of direction imposed on the air flow in the secondary channel force the water droplets transported by this air flow to remain in a part of the secondary channel. The particular way in which the means is arranged prevents the water from getting as far as the motor cradle duct and damaging the motor. 
         [0009]    In one particular embodiment, said means comprises at least one wall dividing said secondary channel into at least two sub-channels. The creation of two sub-channels makes it possible to impose a special route on the air flowing through the sub-channels. Moreover, one of the two sub-channels performs two functions—collecting water droplets transported in the air flow, and removing these collected droplets. 
         [0010]    Advantageously, one wall of the second sub-channel doubles as the wall of the volute tongue of the casing. Sitting the second sub-channel here allows an unused region of the casing to be occupied. Placing the second sub-channel in the volute tongue therefore makes the casing easy to fabricate and cheap to produce. Further, this sub-channel is placed in this region for fluid-flow reasons, to avoid head losses. 
         [0011]    Advantageously, the means also includes the inlet and the outlet, these being arranged at one end of the secondary channel, and it includes the wall which contains an opening between the two sub-channels, said opening being arranged at the opposite end from the end where the inlet and outlet are located. The particular arrangement of the inlet and outlet with respect to the opening makes it possible to form a baffle which will force the air flow to change direction at least twice before it reaches the outlet. This baffle thus prevents water reaching the outlet. 
         [0012]    Advantageously, the inlet of the secondary channel is defined by a rim, the opening is defined by an edge, and the rim is located at a height less than the height of the edge in relation to the total height of the secondary channel. This arrangement of the inlet relative to the opening ensures that air flowing through the secondary channel cannot travel along the sub-channel comprising the outlet without changing direction. 
         [0013]    Advantageously, the wall forming the sub-channels and the wall of the casing containing the inlet are perpendicular to each other. The arrangement of these two walls again simplifies the production of the secondary channel. 
         [0014]    Advantageously, the casing comprises two half-shells engaging at a parting line, at least one of which two half-shells includes, projecting from the parting line, a part whose free end at least partially defines the inlet. 
         [0015]    Advantageously, said casing comprises two half-shells engaging at a parting line, at least one of which two half-shells includes, projecting from the parting line, a part whose free end at least partially defines the opening. This two half-shell structure makes it easy to mold the sub-channels. This means that the manufacturing cost does not have to be increased because an extra part can be inserted to form both the secondary channel and the wall dividing it into two sub-channels. 
         [0016]    Advantageously, a heating and/or air conditioning system comprises a ventilation device that incorporates at least one of the features indicated above. 
     
     
         [0017]    A clearer understanding of the invention and of other of its advantages will be gained from a perusal of the following description of an embodiment of the ventilation device conforming to its principle. This description is presented purely by way of example with reference to the attached drawings, in which: 
           [0018]      FIG. 1  is a schematic view of a prior-art ventilation device for a motor vehicle, 
           [0019]      FIG. 1   b  is a schematic cross section taken on plane B as marked in  FIG. 1 , 
           [0020]      FIG. 1   c  is a schematic cross section taken on plane C as marked in  FIG. 1 , 
           [0021]      FIG. 2  is a schematic view of the invention, 
           [0022]      FIG. 3  is a perspective view of the casing  6 , 
           [0023]      FIG. 4  is a cross section taken on plane P 1  as marked in  FIG. 3 , 
           [0024]      FIG. 5  is another cross section taken on P 1  as marked in  FIG. 3 , seen from a different angle than  FIG. 4 , 
           [0025]      FIG. 6  is a cross section taken on VI-VI as marked in  FIG. 4 , 
           [0026]      FIG. 7  is a cross section on VII-VII as marked in  FIG. 4 , 
           [0027]      FIG. 8  is a schematic view of an air conditioning system fitted with a ventilation device as claimed, 
           [0028]      FIG. 9  is an enlarged cross section taken on IX-IX through the part of the air conditioning system where the evaporator is located, and 
           [0029]      FIG. 10  is a cross section taken on plane P 1  through another embodiment. 
       
    
    
     DESCRIPTION OF THE INVENTION  
       [0030]    Parts that are common both to the prior art illustrated in  FIGS. 1-1   c  and to the invention to which this application relates are given the same references. 
         [0031]      FIGS. 2-7  show a ventilation device  1 , itself designed to be incorporated into a ventilation/heating, ventilation/heating/air conditioning or ventilation/air conditioning appliance for a motor vehicle.  FIG. 8  illustrates a ventilation/heating/air conditioning system  100  comprising the ventilation device  1  consisting of a casing  6  in the form of a volute, a blower impeller  5 , and channels ( 7 ,  8 ,  15  and  16 ). The system  100  also comprises an evaporator  200  and a radiator  300  (both located in the main channel  7 ), distribution flaps  400 , and air outlets  500  to the cabin. 
         [0032]    A ventilation device  1  is shown in  FIGS. 2 and 3 . This ventilation device  1  comprises: a volute-shaped casing  6 , that is, a casing defining a circular air channel whose cross section increases between a volute tongue and an air outlet; an electric motor  4 ; and a blower impeller  5  driven by the motor  4 . 
         [0033]    The casing  6  comprises the same parts as those of the prior art illustrated in  FIGS. 1-1   c , namely a peripheral wall  6   a , first and second open ends  6   b ,  6   c , and a main channel  7 . This casing  6  also contains a motor  4 , a blower impeller  5  with vanes  5   a , and a motor cradle  9  similar to that shown in  FIGS. 1   b  and  1   c.    
         [0034]    The main air channel  7  directs to an air outlet  10  of the casing  6  an air flow  3  created by the blower impeller  5  in the casing  6 . This main air channel  7  is usually rectangular sectioned, but it can be square sectioned, or be cylindrical or be of any other shape in another embodiment. The main channel  7  is defined by an upper wall  7   a , a lower wall  7   b , and two side walls  7   c ,  7   d . The side wall  7   c  contains an inlet  11  through which some of the air flow  3  is able to enter the secondary channel  8 . The main channel  7  forms with the peripheral wall  6   a  a volute tongue  13 . This volute tongue  13  is that part of the wall of the casing  6  which connects the peripheral wall  6   a  to the side wall  7   c  of the main channel  7 . 
         [0035]    As illustrated in  FIGS. 2 ,  4 , and  6 , the secondary air channel  8  has a peripheral wall  8   a , an upper wall  8   b , a lower wall  8   c , an inlet  11 , and an outlet  12 . Said secondary channel  8  is located in the volute tongue  13 . More precisely, part of the peripheral wall  8   a  of the secondary channel  8  is shared with that part of the peripheral wall  6   a  of the casing  6  which forms the volute tongue  13  and with part of the side wall  7   c . The secondary channel  8  extends transversely along the peripheral wall  6   a  of the casing  6 . The outlet  12  lies in a plane P containing the end  6   c  of the casing  6  and communicates with a duct  9   a  formed into the motor cradle  9  as can be seen in  FIG. 1   c , plane P being the plane of the paper in  FIG. 4 . This duct allows an air flow to reach and cool the electric motor  4 . 
         [0036]    The air flow  3  produced by the blower impeller  5  travels along both the main channel  7  and the secondary channel  8 . One part  3   a  of the air flow  3  flows along the main channel  7  to supply the rest of the ventilation, heating and/or air conditioning system, and another part  3   b  enters the secondary channel  8  via the inlet  11 . As indicated in  FIG. 1   c , when the air flow  3   b  traveling along the secondary channel  8  passes out of the latter, it comes to the duct  9   a  of the motor cradle  9  and passes through it to cool the electric motor  4 . 
         [0037]    According to the invention, the secondary channel  8  comprises a means  14  enabling the secondary air flow  3   b  to change direction at least twice as the air flow  3   b  travels along the secondary channel  8 . This means is a wall  14   a  dividing said secondary channel  8  into two sub-channels  15 ,  16 . 
         [0038]    As illustrated in  FIGS. 4 and 5 , the wall  14   a  separates the secondary channel  8  into a first sub-channel  15  and a second sub-channel  16 . The first sub-channel  15  is that containing the inlet  11  and the second sub-channel  16  is that containing the outlet  12 . In addition, the second sub-channel  16  shares a wall  16   a  with that wall of the volute tongue  13  of the casing  6 . 
         [0039]    As illustrated in  FIGS. 5 ,  6 , and  7 , an opening  17  is provided in the wall  14   a . The position of this opening  17  depends on the position of the inlet  11  and on that of the outlet  12 . Firstly, the inlet  11  is situated at the bottom of the side wall  7   c , i.e. in that part of the side wall  7   c  which is close to the lower wall  7   b , and secondly, the inlet  11  and the outlet  12  are both located at the same end of the secondary channel  8  while the opening  17  is situated at the opposite end to the inlet  11  and outlet  12 . In other words, the inlet  11  and the outlet  12  are formed near the lower wall  8   c  of the secondary channel and the opening  17  is formed in the wall  14   a  adjacent to the upper wall  8   b.    
         [0040]    Furthermore, the opening  17  is defined by an edge  18  and the inlet  11  by a rim  19 . The term “edge” is used here to mean the entire perimeter of the surface forming the opening  17 , and the term “rim” the entire perimeter of the surface forming the inlet  11 . Hence both the edge  18  and the rim  19  consist of several sides if they are polygonal, one side if they are circular. The positioning of the opening  17  in the wall  14   a  is also relative to the position of the inlet  11  in the peripheral wall  8   a . To cause the air flow  3   b  in the secondary channel  8  to change direction, the rim  19  of the inlet  11  is located at a height less than the height of the edge  18  of the opening  17  in relation to the total height-the height of the peripheral wall  8   a  of the secondary channel  8 . In other words, the edge  18  and the rim  19  are located with respect to each other in such a way that the air flow  3   b  that has just entered the first sub-channel  15  through the inlet  11  cannot pass into the second sub-channel  16  via the opening  17  without changing direction. 
         [0041]    Owing to the arrangement of this opening  17 , the path of the air flow  3   b  is defined by the inlet  11 , the first sub-channel  15 , the wall.  14   a , the opening  17 , the second sub-channel  16 , and the outlet  12 . Thus, this assembly ( 11 ,  15 ,  14   a ,  17 ,  16 , and  12 ) represents a “baffle” for the air flow  3   b  and forms the means  14 . This baffle allows the air flow  3   b  to dump its water droplets, which will remain in the first sub-channel  15 . 
         [0042]    As shown in  FIGS. 8 and 9 , water  27  collected in the first sub-channel  15  can then be drained off through the inlet  11  since the latter is at the bottom of the side wall  7   c . Moreover, this water  27  drained off through the inlet  11  is conveyed to the evaporator  200  and finally removed from the vehicle via a condensate pipe  600  passing out of the evaporator  200  through the floor of the vehicle  700 . The baffle structure therefore produces a water droplet-free air flow at the outlet  12  of the secondary channel  8  that passes through the duct of the motor cradle to cool the electric motor  4 . 
         [0043]    As explained earlier, the baffle structure of the secondary channel  8  enables the air flow  3   b  to change direction at least twice. The direction-changing air flow  3   b  is that taken from the air flow  3  through the inlet  11 . The air flow  3   b  to be considered is therefore an air flow already present in the secondary channel  8  and moving in any direction inside this secondary channel  8 . The location of the inlet  11  with respect to the opening  17  in the wall  14   a  thus forces this air flow  3   b  to change direction at least twice before it reaches the outlet  12  of the secondary channel  8 . The expression “change direction” here refers to any change of orientation imposed on the air flow by the means  14  situated in the secondary channel  8 . 
         [0044]    As shown in  FIGS. 3-7 , the casing  6  is made up of two half-shells  2   a ,  2   b . These two half-shells  2   a ,  2   b  engage at a parting line  20 . At the secondary channel  8 , these two half-shells slot together to form said secondary channel with its inlet  11  and its wall  14   a . More precisely, once the casing  6  is formed, half-shell  2   a  comprises, projecting from the parting line  20 , a part  21  whose free end  22  at least partially defines the inlet  11 . 
         [0045]    In an alternative, the other half-shell  2   b  comprises, projecting from the parting line  20 , a part  23  whose free end  24  at least partially defines the opening  17 . “Partially” here indicates the fact that the free end  22  defines one side of the rim  19 , the other sides being defined by the other half-shell. Likewise “partially” indicates the fact that the end  24  defines one side of the edge  18 , the other sides being defined by the other half-shell. In order to create the baffle structure, the projecting parts  21  and  23  extend in opposite directions. The general idea of the invention is to stagger the inlet  11  and the opening  17  in one direction so as to form this baffle. 
         [0046]    In a preferred embodiment, the wall  14   a  and the side wall  7   c  containing the inlet  11  are perpendicular to each other. In this embodiment, one edge of the wall  14   a  coincides with the edge of the side wall  7   c  forming one side of the rim  19 . 
         [0047]    In another embodiment, the secondary channel  8  comprises two walls  14   a . The general idea of the invention being to form one or more baffles to divert the air flow traveling through said secondary channel  8 , a second opening  17 ′ in a second wall  14   a ′ is provided at the same end of the secondary channel  8  as the inlet  11 . This means that the outlet  12  will be situated at the same end of the secondary channel  8  as the first opening  17 . 
         [0048]    In general terms, where the invention comprises more than one wall  14   a , each opening  17 ,  17 ′,  17 ″,  17 ′″, etc., is dependent on the position of the preceding opening with respect to the movement of the air flow in the secondary channel  8 , in order to form the baffle structure. Of course, the first opening  17  after the inlet  11  will always be located as in the first embodiment. Also, the position of the outlet  12  may change, i.e. it may either be in the lower wall  8   c , or be at the top of the peripheral wall  8   a , depending on how many walls  14   a  there are in the secondary channel  8 . 
         [0049]    Concerning the rim  19  of the inlet  11  and the edge  18  of the opening  17 , their arrangement in the secondary channel  8  must also conform with the need to form a baffle for the air flow  3   b . Since the inlet  11  and the first opening  17  do not change position, the rim  19  and the edge  18  are at different heights as already described in this application. The edge  18 ′ of the second opening  17 ′ must be at a height less than the height of the edge  18  of the first opening  17  in relation to the total height of the secondary channel  8 . In the same way, the n-th edge  18  of the n-th opening  17  must be at a height greater or less than the height of the (n-1)th edge of the (n-1)th opening  17  in order to form a baffle for the air flow  3   b . Lastly, the outlet  12  must be positioned so as to respect the baffle structure in relation to the number of walls  14   a  (and therefore of openings  17 ) present in the secondary channel  8 . 
         [0050]    In a variant of the previous embodiment, the inlet  11  to the secondary channel  8  is situated in a-cavity. 25 . As shown in  FIG. 10 , the cavity  25  is defined by the side wall  7   c  of the main channel  7  and is U-shaped. This cavity  25  communicates with the main channel  7  via an opening  26 . This opening  26  has a height equal to the height of the main channel  7 , i.e. the opening  26  extends transversely all the way up the side wall  7   c . The location of this cavity  25  allows that part of the air flow  3   b  which is to pass along the secondary channel  8  to first enter the cavity  25  and then move into the secondary channel  8  through the inlet  11 . In this embodiment, the secondary channel  8  is located in the volute tongue  13  as described earlier. The inlet  11  of the secondary channel  8  is situated in the U-shaped part of the side wall  7   c . Moreover, the inlet  11  is situated in that part of the side wall  7   c  which is near the lower wall  7   b  as described previously. The inlet  11  is thus accessible to the air flow only via the cavity  25 .