Patent Publication Number: US-2021162858-A1

Title: Device for controlling an air flow circulating in a heat exchanger for a motor vehicle and cooling module provided with such a device

Description:
FIELD OF THE INVENTION 
     The invention relates to a device for controlling a flow of air circulating in a heat exchanger for a motor vehicle and to a cooling module provided with such a device. It is intended in particular for equipment of a motor vehicle front end. 
     PRIOR ART 
     Motor vehicle cooling modules comprising two heat exchangers are known. A first heat exchanger has the function of cooling an auxiliary circuit of the vehicle, such as an air conditioning device or a charge air cooling device. A second heat exchanger is needed for cooling the engine of the vehicle. These heat exchangers are arranged in the front end of the vehicle, assembled and aligned in series so that the airflow entering through the vehicle radiator grille passes through them in succession. They typically comprise a heat exchange core bundle comprising tubes in which the fluid that is to be cooled circulates and through which the air coming from the grille passes. 
     In order to separate the cooling of the two heat exchangers and optimize the aerodynamic performance of each heat exchanger, the applicant has recently proposed a device for regulating the flow of air intended to circulate in heat exchangers, in an unpublished patent application by the applicant. The regulating device comprises two curtains mounted in a frame and able to be moved alternately in translational movement between two positions: open and closed. By moving according to these two positions, the curtains allow the regulating device to allow the passage or alternatively to block the passage of the flow of air passing through the radiator grille of the motor vehicle. The curtains are moved by means of a transmission system which guides the movement of said curtains in translational movement, and an actuator causing the transmission system to move. The transmission system is equipped with a set of belts and pulleys which is connected to the curtains by filamentary connections. 
     One disadvantage with this device lies in the limited ability of the curtain-moving members to withstand thermal shock. Now, such members may be faced with temperature variations because of the proximity of the exchangers. In the event of an excessively great expansion, the driving of the curtains may thereby be disrupted, and this detracts from correct control of the level of opening/closing of the curtains and therefore from correct regulation of the temperature of the fluids circulating in the exchanger. 
     It is an objective of the invention to at least partially overcome the aforementioned disadvantages and the invention for this reason proposes a device for regulating a flow of air intended to circulate through a heat exchanger for a motor vehicle, the device comprising at least two curtains able to move in a direction of opening/closing, a transmission system connected fixedly or via a guided mechanical connection, to at least two rigid drive members, said drive members being able to drive said curtains between a closed position that blocks off the passage of the flow of air and an open position that allows the flow of air to pass by moving in said direction of opening/closing. 
     What is meant by “fixedly or via a guided mechanical connection” is that the transmission system is connected to said rigid drive members by a non-flexible connection. This in particular is a fixed connection or connection with just one degree of freedom, for example a connection in translation. 
     This then yields a regulating device of which the elements exhibit high resistance to thermal shock, which means that they are more able to withstand the temperature variations caused by the heat exchanger(s) situated nearby. 
     The regulating device according to the invention thus makes it possible to limit the uncertainty regarding the degree of opening/closing of the curtains and thereby optimize the regulation of the temperature of the fluids circulating through the heat exchanger(s). 
     According to various features of the invention which may be considered together or separately:
         the drive members are drive rods connected to the curtain;   said transmission system is configured so that said curtains move symmetrically with respect to one another;   the regulating device comprises at least one actuator configured to drive said transmission system;   said device comprises at least one shaft for rolling-up/unrolling the curtains;   said shaft for rolling-up/unrolling the curtains comprises means for tensioning the curtains;   in a first variant, said transmission system comprises at least one pinion;   said actuator comprises a drive shaft, said drive shaft being able to effect a rotational movement about an axis oriented in a direction Y perpendicular to a direction Z, corresponding to the direction of opening/closing, in a plane of extension of the curtains in the closed position;   said pinion is connected with said actuator, notably said drive shaft, so as to be guided in rotation by said drive shaft;   said transmission system comprises two toothed spindles meshing with said pinion;   said toothed spindles oppose one another in a direction X orthogonal to the plane of extension of the curtains in the closed position;   said drive members are connected fixedly to said toothed spindles;   in a second variant, said transmission system comprises an endless screw with threads of opposing hand, which is coupled to the actuator;   said actuator comprises a drive shaft, said drive shaft being able to effect a rotational movement about an axis oriented in a direction Y perpendicular to a direction Z, corresponding to the direction of opening/closing, in a plane of extension of the curtains in the closed position;   said actuator comprises a first angle member connected to the drive shaft and having a beveled edge;   the transmission member comprises a second angle member connected to the endless screw and having a beveled edge, said edge of the second angle member conforming to the beveled edge of the first angle member;   said endless screw is coupled to the drive shaft via said first and second angle members;   said transmission system further comprises a first nut with a right-hand thread and a second nut with a left-hand thread, said first and second nuts meshing with the endless screw;   said drive members are connected to said nuts fixedly;   in a third variant, the actuator comprises at least two drive shafts each connected to said actuator(s), said drive shafts being able to effect a rotational movement about axes oriented in a direction X orthogonal to the plane of extension of the curtains in the closed position;   a first and a second of the drive shafts are connected by a belt;   the transmission system comprises two pushing arms which are coupled to the drive shafts, said pushing arms being guided in rotation by the drive shafts;   said transmission system comprises two carriages, said carriages being coupled to the pushing arms by a pivot connection and to the drive members by a slideway connection;   each of said drive members is connected to a slider, said slider being guided in a first slideway, said first slideway being fixed to a first lateral beam of a frame holding said curtains;   each of said drive members is connected to a second slider, said slider being guided in a second slideway, said second slideway being fixed to a second lateral beam of the frame;   the second beam is opposite the first lateral beam of the frame;   in another variant, said transmission system comprises:
           at least two pushing arms able to effect a rotational movement about an axis of rotation orthogonal to a plane of extension of the curtains in the closed position,   at least two carriages able to move between a proximal position and a distal position along said drive members, under the action of the pushing arms,   the transmission system being configured in such a way as to convert the rotational movement of the pushing arms into a translational movement of the drive members in the direction of opening/closing, via said carriages.   That yields a regulating device in which the operation of the transmission system is reliant on the conversion of a rotational movement through a limited angle into a translational movement, forcing the curtains to move in the direction of opening/closing. That on the one hand allows the forces to be transmitted effectively between the various elements that make up the device and, on the other hand, makes it possible to substantially increase the speed of travel of the drive members, situated at the output side of the transmission system.   
               

     The invention also relates to a cooling module comprising a regulating device as described above. 
     Advantageously, the module comprises:
         a low-temperature heat exchanger,   a high-temperature heat exchanger,       

     the low-temperature heat exchanger being positioned upstream of the regulating device, and the high-temperature heat exchanger being positioned downstream of the regulating device. 
    
    
     
       PRESENTATION OF THE FIGURES 
       Other objects, features and advantages of the invention will become more clearly apparent from the description which follows, given with reference to the appended figures, in which: 
         FIG. 1 a    schematically illustrates, in side view, the front end of a vehicle comprising a cooling module equipped with a regulating device according to a first embodiment of the invention; 
         FIG. 1 b    is a view of  FIG. 1 a    zooming in on the area of the regulating device; 
         FIGS. 1 c , 2 a  and 3 a    illustrate, in a schematic face-on view, a regulating device according to the first, a second and a third embodiment of the invention, respectively, with the curtains in the open position; 
         FIGS. 1 d , 2 b  and 3 b    illustrate, in a schematic face-on view, a regulating device according to the first, the second and the third embodiments of the invention, respectively, with the curtains in the closed position; 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 a    to  1   d  illustrate a first embodiment of the invention.  FIG. 1 a    illustrates a regulating device  10  regulating a flow F of air, and a cooling module  1 , both according to the invention, in a side view. The cooling module  1  extends depthwise in a direction X intended to correspond to the longitudinal axis of the vehicle equipped. The flow F of air is substantially parallel to the direction X. The module is configured to be fixed to a support, such as a chassis of the vehicle. 
     The cooling module  1  comprises an upstream heat exchanger  2  (situated to the left in  FIG. 1 a   ) and a downstream heat exchanger  3  (situated to the right in  FIG. 1 a   ) which are arranged in series in the direction of flow of the flow F of air passing through them. In other words, the cooling module  1  is configured to be arranged on its support in such a way that the upstream heat exchanger  2  has the flow F of air passing through it first, and the downstream heat exchanger  3  second. 
     The upstream heat exchanger  2  is a cooling radiator, referred to as low temperature, used to cool a liquid coolant of a heat-exchange loop, referred to as a low-temperature loop, notably comprising a charge air cooler and/or an air conditioning condenser. The downstream heat exchanger  3  is, for example, a high-temperature cooling radiator intended to cool a liquid coolant of a heat exchange loop comprising an engine of the vehicle. The air which passes through this downstream exchanger  3  cools the engine coolant. 
     Each exchanger  2 ,  3  comprises for example a heat exchange core bundle and header tanks positioned laterally on either side of the core bundle (not illustrated). The core bundle has the flow F of air passing through it. It comprises a set of mutually parallel tubes opening into the header chambers, for the circulation of the liquid coolant (not illustrated). 
     The cooling module  1  is advantageously configured to allow a substantially fluidtight flow of air between said heat exchangers  2 ,  3 , which is to say that the upstream heat exchanger  2  and the downstream heat exchanger  3  are assembled with one another in such a way that the downstream heat exchanger  3  does not have air coming from outside the module passing through it directly. In other words, the flow F of air passing through the downstream heat exchanger  3  comes from the flow of air passing through the upstream heat exchanger  2 . For that, the cooling module  1  may, for example, comprise sealing means guiding all of the flow of air that has passed through the upstream heat exchanger  2  toward the downstream heat exchanger  3  without a loss of air throughput. These sealing means, which are not illustrated, may for example comprise ducting arranged between the two heat exchangers  2 ,  3 . 
     To facilitate the passage of the flow of air through the cooling module  1 , notably when the vehicle is stationary, the module advantageously comprises a motorized fan unit  4  able to cause the air to circulate through the cooling module  1 . As illustrated in  FIG. 1 a   , the motorized fan unit  4  in this instance is positioned downstream of the downstream heat exchanger  3 , the motorized fan unit  4  being configured to draw air from an air intake of the vehicle, which is preferably defined by the radiator grille thereof. 
     The cooling module  1  according to the invention further comprises a regulating device  10  regulating the air flow and preferably positioned between the upstream heat exchanger  2  and the downstream heat exchanger  3 . The regulating device  10  has a small thickness in the depth of the cooling module. The regulating device  10  controls the passage of the flow F of air from the upstream heat exchanger  2  toward the downstream heat exchanger  3  via blinds or curtains  11  that can be rolled-up/unrolled. 
     In a variant, the cooling module  1  according to the invention may comprise a single heat exchanger, for example a cooling radiator, said regulating device  10  then being arranged upstream or downstream of said heat exchanger. In such a configuration, the flow F of air passing through the heat exchanger comes from the flow F of air passing through the regulating device or opens onto said regulating device. 
     The cooling module is able to be rotated by 90° in the direction X without the operation of the regulating device being impaired, depending on the architecture of the exchangers. By way of example, such architectures may be used for the purposes of reducing thermal shock. 
     With reference to  FIGS. 1 c  and 1 d   , the regulating device  10  according to a first embodiment of the invention is illustrated in a schematic face-on view. The device comprises two curtains  11  of rectangular overall shape. Each curtain  11  is delimited by a proximal edge  11   a , two lateral edges  11   b , and a distal edge  11   c . Said lateral edges  11   b  are opposite and substantially parallel to a direction Z, orthogonal to the direction X, while said proximal edge  11   a  and said distal edge  11   c  are opposite and substantially parallel to a direction Y, orthogonal to the directions X and Z, the direction Z here representing the vertical. 
     In  FIG. 1 c   , the regulating device  10  is in the open position P O , which means to say that the curtains  11  allow the airflow F to pass. In this configuration, the proximal edges  11   a  of said curtains  11  are distant from one another. More specifically, a first proximal edge  11   a  is situated in the vicinity of an upper beam of a frame  50  of the regulating device, notably at the level of a first open position P O1 , whereas a second proximal edge  11   a  is situated in the vicinity of a lower beam of the frame  50 , notably at the level of a second open position P O2 , opposite to P O1  with respect to an axis passing through a dotted line P F -P F . 
     The regulating device  10  further comprises shafts  53  for rolling-up/unrolling the curtains, and which are connected to the frame  50  by articulating bearings  52 . 
     As a preference, each curtain  11  is kept taut by a tensioning means  54  connected to its distal edge  11   c . The tensioning means  54  apply a force to the curtains  11  so that said curtains are continuously kept taut. For example, the tensioning means  54  may be springs, notably spiral springs, or any other means that allows said curtains  11  to be kept taut. As a preference, each tensioning means  54  is connected on the one hand to the frame  50  and on the other hand to the rolling-up/unrolling shaft  53 . 
     In  FIG. 1 d   , the regulating device  10  is in the closed position RE. The curtains  11  extend in a plane, referred to as the plane of extension of the curtains in the closed position. Said plane of extension of the curtains in the closed position is oriented in the direction Z, corresponding to the direction of opening/closing of the curtains, and to the direction Y. In other words, said plane of extension of the curtains in the closed position extends transversely to the air flow F. In this configuration, the respective proximal edges  11   a  of said curtains are in contact with one another at the dotted line P F -P F . The curtains  11  therefore block off the passage of the flow F of air which circulates perpendicular to the plane of extension of the curtains in the closed position. 
     The regulating device  10  is configured so that said curtains  11  are able to move in the direction of opening/closing Z, in said plane of extension of the curtains in the closed position. In other words, the device is able, alternately, to adopt the configurations illustrated in  FIGS. 1 c  and 1 d   . For this purpose, the regulating device  10  comprises a transmission system  20  and at least two drive members  30  connected to said transmission system  20 . 
     The features and the principle of operation of a first embodiment of the transmission system  20  are described hereinbelow with reference to  FIGS. 1 b    and  1   c.    
     As a preference, the transmission system  20  comprises pinions  21 . As can best be seen in  FIG. 1 b   , said pinions  21  comprise a peripheral edge  21   a  and a toothset  21   b  situated on said peripheral edge  21   a . The pinions  21  are able to pivot, in the clockwise direction or, conversely, in the counterclockwise direction, about an axis oriented in the direction Y. 
     For this purpose, the regulating device  10  preferably comprises at least one actuator  40  configured to drive said transmission system  20 . The actuator comprises a drive shaft  41 , able to rotate about the axis of rotation of said pinions  21 . The actuator  40  further comprises a hydraulic or pneumatic cylinder or, more generally, any drive member able to induce a rotational movement of the drive shaft  41 . The drive shaft  41  is connected with the pinions  21 . As a preference, the drive member of the actuator  40  is situated outside of the frame  50 . 
     As a preference, said drive shaft  41  is a cylindrical spindle extending between two lateral beams of the frame  50 , in a plane orthogonal to the plane of extension of the curtains in the closed position, and along the dotted line P F -P F . As a preference, an inner edge of the pinions  21  conforms to the shape of the drive shaft  41 , which means to say that said inner edge espouses the contour of the drive shaft  41  so that said pinions  21  can be guided in rotation by the drive shaft  41 . The drive shaft  41  is articulated on bearings  52 ′ which are connected to the frame  50 . 
     The transmission system  20  may further comprise two racks or toothed spindles  22  substantially parallel to the direction Z. As can best be seen in  FIG. 1 b   , each toothed spindle  22  has a toothset  22   a  and a plane edge  22   b . Said toothed spindles  22  mesh with said pinion  21  via their respective toothsets  22   a . In other words, the toothset  22   a  of the toothed spindles  22  conforms exactly to the toothset  21   b  of the pinion  21 . The toothed spindles  22  are situated on either side of the pinion  21  in the direction X. Thus, in  FIG. 1 c   , a first toothed spindle  22 , of which the toothset  22   a  can be seen in a position P t2 , is connected to a first curtain  11  situated below the dotted line P F -P F , whereas a second toothed spindle  22 , of which the plane edge  22   b  can be seen in a position P t1 , is connected to a second curtain  11  situated above the dotted line P F -P F . 
     When the pinion  21  turns, the toothed spindles  22 , of which the toothsets  22   a  can be seen in the position P t2  slide in the direction of the upper beam of the frame  50 , namely toward the position P t1 , while at the same time, the toothed spindles  22  of which the plane edges  22   b  can be seen in the position P t1  slide in the direction of the lower beam of the frame  50 , namely the position P t2 . The toothed spindles  22  are therefore able to effect translational movements that are symmetrically opposed in the direction Z. 
     Advantageously, the pinions  21  and a corresponding pair of toothed spindles  22  are situated symmetrically on each side of said curtains  11 . In this configuration, when the actuator  40  is in operation, the transmission system  20  is capable of driving the drive members  30 , to which it is connected, while maintaining the horizontality of said drive members with respect to the direction Y. 
     As mentioned previously, the regulating device  10  further comprises at least 10 drive members  30 . Their features and their operation are described hereinbelow. 
     In general, said drive members  30  are connected to the transmission system  20 . Said drive members  30  are rigid. Furthermore, said drive members  30  are connected, fixedly or with guided mechanical connection, to the transmission system  20 . Once again stated differently, said drive members  30  are not connected to the transmission system  20  in a filamentary manner. That makes it possible to improve the ability of the regulating device  10  to withstand both mechanical stress and thermal shock. It also allows the regulating device  10 , and the installation thereof, to be simplified. 
     More specifically, in the embodiment of  FIGS. 1 a    to  1   d , each drive member  30  is attached to one of said toothed spindles  22  such that any sliding of said toothed spindles  22  in the direction Z leads to a translational movement of said members  30  in the same direction. For example, the toothed spindle  22 , of which the toothset  22   a  moves from the position P T1  to the position P T2 , leads to a movement of the drive member  30 , to which it is connected, from a distal position close to the rolling-up/unrolling shaft  53  toward a proximal position close to the shaft  41 . 
     As a preference, the drive members  30  are rigid drive rods. Said drive rods  30  connect together, in twos, said toothed spindles  22  and are able to be translationally guided by said toothed spindles  22 . Said drive rods  30  are directly connected to said curtains  11 , so that any translational movement of said drive rod in the direction Z induces a translational movement of said curtain  11  in the same direction. Furthermore, because the drive members  30  are kept horizontal by the duplication of the pinion  21  and of the rods  22  on each side of the curtains  11 , the edges  11   a  are therefore kept horizontal. That also allows loads to be distributed symmetrically over the drive members  30 . 
     As can best be seen in the example illustrated in  FIG. 1 b   , the toothed spindle  22  situated in the upper part (to the left in the drawing) is rectilinear, and the associated drive rod is attached to an upper end of said toothed spindle  22 , The toothed spindle  22  situated in the lower part (to the right in the drawing) has an L-shaped configuration, the long leg of the L having the toothset and the short leg ending in the continuation of the other toothed spindle  22 . The drive rod associated with the L-shaped toothed spindle  22  is situated at the free end of said short leg of the L, such that the two curtains  11  are substantially in the same plane. 
     In a variant, said drive members  30  may be studs connected fixedly on the one hand to the transmission system  20  and on the other hand to the curtains  11 . The studs are provided on each side of each of the curtains  11 , each proximal corner of the curtains therefore being fixed to said studs. 
     The principle of closing the curtains  11  is as follows. 
     When the actuator  40  is activated, the pinions  21  effect a rotational movement about their axis of rotation. This rotational movement of the pinions  21  induces a translational movement of the toothed spindles  22  which are respectively associated with them, in the direction Z. As illustrated in  FIG. 1 d   , said toothed spindles  22 , of which the toothsets  22   a  are initially situated in a position P t2 , move from the position P t2  toward the position P t1 , and, conversely, the toothed spindles  22  of which the plane edges  22   b  are initially situated in the position P t1 , move from said position P t1  toward the position P t2 . 
     Incidentally, the drive members  30  connected to said toothed spindles  22  are simultaneously guided in translation in opposite directions and drive the curtains  11  in their movement. As they move, the drive members  30  guide said curtains  11  such that their proximal edges  11   a , initially situated in positions P O1  and P O2 , reach the closed position P F  and find themselves in contact with one another, or are even overlapping. 
     Because the two pinions  21  are driven simultaneously by the drive shaft  40 , the curtains  11  are guided symmetrically with respect to one another as they move. The distance separating the two curtains  11 , notably the proximal edges  11   a  thereof, remains equal on either side of the dotted line P F -P F , throughout their entire movement. When the curtains  11  are in contact, or even overlapping, they therefore do not allow the passage of the flow F of air circulating perpendicular to the plane of extension of the curtains in the closed position. 
     Conversely, the curtains  11  are able to return to their original position (as illustrated in  FIG. 1 c   ) by moving in the direction of opening/closing Z, for example when the actuator  40  is no longer in operation. Specifically, because the curtain tensioning means  54  continuously exert a force on the curtains  11 , said curtains  11  roll up again around their respective rolling-up/unrolling shaft  53  and the elements of said transmission system  20  and the drive members  30  return to their original position. 
       FIGS. 2 a  and 2 b    illustrate, in a schematic face-on view, a second embodiment of the invention. This embodiment of the invention differs from the previous one through the features and operation of the transmission system  20  and of the drive members  30 . All the rest, notably everything relating to said curtains  11  and their layout within the frame  50 , is unchanged. 
     Thus, in a similar way to the first embodiment, said curtains  11  are able to move in the direction of opening/closing Z in said plane of extension of the curtains in the closed position, and the regulating device  10  for that purpose comprises a transmission system  20  and at least two drive members  30  which are connected to said transmission system  20 . 
     The transmission system  20  according to this second embodiment comprises an endless screw  23  substantially parallel to the direction Z. Said endless screw  23  has a cylindrical overall shape and comprises screw threads of opposing hand. More specifically, an upper portion of said endless screw  23 , notably situated above the dotted line P F -P F , comprises helical splines  23   a  oriented to the left or to the right, whereas a lower portion of said endless screw  23 , notably situated below the dotted line P F -P F , comprises splines  23   b  oriented in the opposite direction, for example to the left if the thread of said upper portion is oriented to the right. 
     Said endless screw  23  is coupled to an actuator  40 . As in the previous embodiment, the actuator  40  comprises a drive shaft  41  driven in rotation by the drive member about an axis oriented in the direction Y. Said drive member and said drive shaft  41  are similar in their respective nature and mode of operation, to that which was seen in the first embodiment, and differ only in terms of the features mentioned in the sections which follow. 
     As a preference, said drive shaft  41  comprises, at one of its ends, a first angle member  43 . Said angle member  43  has a plane edge in direct contact with a bearing  52 ′ and a beveled edge in direct contact with said endless screw  23 . For this purpose, the endless screw  23  also comprises a second angle member  23   c . Said endless screw  23  is coupled to the drive shaft  41  via their said angle members  43 ,  23   c . In this configuration, when the angle member  43  effects a rotational movement, induced by the drive shaft  41 , about an axis oriented in the direction Y, that leads to a rotational movement of the endless screw  23 , via the angle member  23   c , about an axis oriented in the direction Z. 
     The transmission system  20  may further comprise two nuts  24  meshing with the endless screw  23  and situated in a position P EI1  and in a position P EI2 , respectively. More specifically, one of said nuts  24  meshes with the upper portion of the endless screw, while the other meshes with the lower portion of the endless screw. For this purpose, a first nut  24  has a right-hand thread and a second nut  24  has a left-hand thread. 
     In such a configuration, when the endless screw  23  rotates about an axis oriented in the direction Z, the first nut  24  moves between the position P EI1  and a position P EF1 , while the second nut  24  moves in the other direction between the position P EI2  and a position P EF2 , symmetrically opposed to the position P EF1  with respect to the axis passing through the dotted line P F -P F . 
     Advantageously, the endless screw  23  and said corresponding nuts  24  are duplicated on each side of said curtains  11 . In this configuration, when the actuator  40  is in operation, the transmission system  20  is capable of driving the drive members  30 , to which it is connected, while maintaining the horizontality of said drive members  30  with respect to the direction Y. 
     Said drive members  30  are connected here to the nuts  24 . Incidentally, any movement of said nuts  24  in the direction Z leads to a translational movement of the drive members  30  in the same direction. For example, when the first nut  24  effects a translational movement toward the position P EF2 , said first nut  24  guides in translation the drive member  30  to which it is connected, from a distal position close to the rolling-up/unrolling shaft  53 , toward a proximal position, close to the drive shalt  41 . 
     As in the previous embodiment, said drive members  30  may be a rod or, as an alternative, studs connected directly to the curtains  11 . Thus, any translational movement of the guide members  30  in the direction Z leads to a translational movement of said curtain  11  in the same direction. Furthermore, because the drive members  30  are kept horizontal by the duplication of the endless screw  23  and of the nuts  24  on each side of the curtains  11 , the edges  11   a  are therefore kept horizontal. That advantageously allows loads to be distributed symmetrically over the drive members  30 . 
     The principle of closing of the curtains  11  is as follows. 
     When the actuator  40  is in operation, the endless screws  23  situated on each side of said curtains  11  move about their axes. This rotational movement of the endless screws  23  induces a movement of the nuts  24  respectively associated with these screws. The nuts  24  thus effect translational movement along the splines  23   a ,  23   b  of the endless screw. The first nut  24 , initially situated in the position P EI1 , moves from the position P EI1  toward the position P EF1 , and the second nut  24 , initially situated in the position P EI2 , moves from the position P EI2  toward the position P EF2 . 
     Incidentally, the drive members  30  connected to the nuts  24  are simultaneously guided in translation in opposite directions and drive the curtains  11  in their movement. As they move, the drive members  30  connected to the first curtain  11  guide said first curtain  11  in translation, so that its proximal edge  11   a , initially situated in a first open position P O1 , moves toward the closed position P F  while remaining essentially horizontal. At the same time, said second curtain  11  is guided in translation so that its proximal edge  11   a , initially situated in a second open position P O2 , symmetrically opposed to the first open position P O1  with respect to the axis passing through the dotted line P F -P F , moves toward the closed position P F  while remaining essentially horizontal. 
     Because the two endless screws  23  are driven simultaneously by the drive shaft  41 , the curtains  11  are guided symmetrically with respect to one another as they move. The distance separating the two curtains  11 , notably the proximal edges  11   a  thereof, remains equal on either side of the dotted line P F -P F , throughout their entire movement. When the curtains  11  are in contact, or even overlapping, they therefore do not allow the passage of the flow F of air circulating perpendicular to the plane of extension of the curtains in the closed position. 
     Conversely, the curtains are able to return to their original position (illustrated in  FIG. 2 a   ) by moving in the direction of opening/closing Z, for example when the actuator  40  is no longer in operation. Specifically, because the curtain tensioning means  54  continuously exert a force on the curtains  11 , said curtains  11  roll up again around their respective rolling-up/unrolling shaft  53  and the elements of said transmission system  20  and the drive members  30  return to their original position. 
       FIGS. 3 a  and 3 b    illustrate, in a schematic face-on view, a third embodiment of the invention. This embodiment of the invention differs from the previous ones through the features and operation of the transmission system  20  and of the drive members  30 . All the rest, notably everything relating to said curtains  11  and their layout within the frame  50 , is unchanged. 
     Thus, in a similar way to the preceding embodiments, said curtains  11  are able to move in the direction of opening/closing Z in said plane of extension of the curtains in the closed position, and the regulating device  10  for that purpose comprises a transmission system  20  and at least two drive members  30  which are connected to said transmission system  20 . 
     In this embodiment, the transmission system  20  may adopt one of two configurations. 
     In a first configuration, the transmission system  20  comprises two actuators  40 , each one equipped with a drive shaft  41 . Unlike in the preceding embodiments, the drive shafts  41  extend orthogonally to the plane of extension of the curtains in the closed position, notably along axes oriented in the direction X, and are able to rotate about said axes. 
     Furthermore, still in this first configuration, each drive shaft  41  is coupled to a pushing arm  43  and is moreover able to guide said pushing arm  43  in terms of rotation. Thus, when said drive shafts  41  rotate about the axis of rotation thereof, said pushing arms  43  are able to rotate about the same axis. In this configuration, because said pushing arms  43  are not driven by the same actuator  40 , the regulating device  10  may advantageously comprise a synchronizing device so that the pushing arms  43  can be driven synchronously, or not. 
     Alternatively, in a second configuration, the transmission system  20  comprises a single actuator  40  connected to a first drive shaft  41 . In a similar way to the first configuration, said first drive shaft  41  is configured to effect a rotational movement about an axis oriented in the direction X. In this second configuration, a belt  42  connects said first drive shaft  41  to a second drive shaft  41 . 
     Advantageously, the belt  42  may be toothed, namely said belt  42  may comprise teeth. Thus, when said first drive shaft  41  turns, that drives the belt  42  which simultaneously, which means to say synchronously, drives said first drive shaft  41  and said second drive shaft  41 . Advantageously, said pushing arms  43  may therefore be simultaneously guided in rotation by the drive shafts  41  without the need to resort to a device for synchronizing two distant actuators. 
     As a preference, said pushing arms  43  adopt a generally cylindrical shape with a first end connected to a drive shaft  41  and a second end connected to a carriage  25  of the transmission system. Said carriages  25  are pivot-connected to the pushing arms  43  in the direction X orthogonal to the plane of extension of the curtains in the closed position. Thus, when the pushing arms  43  effect a rotational movement about their axis of rotation, said carriages  25  are driven in their turn. 
     Each carriage  25  is furthermore coupled to one of the drive members  30 . Each drive member  30  comprises a drive rod  31  along which the carriage  25  is in a sliding connection, which means to say that the carriage  25  is guided in translation along the drive rod  31 . Incidentally, because the carriages  25  are guided by said pushing arms  43  while at the same time being guided in said drive rods  31 , the rotational movement of the pushing arms  43  induces a translational movement of the carriages  25  along said drive rods, notably between a distal position P D  and a proximal position P P . In addition, as they move, the carriages  25  induce a translational movement of a first of the drive rods  31  toward the position P CF1  and of a second of the drive rods  31  toward the position P CF2 , symmetrically opposed to the position P CF1  with respect to the axis passing through the dotted line P F -P F . The two drive rods  31  are therefore able to move in the direction Z, in opposite directions. 
     In the configuration shown in  FIG. 3 a   , i.e. when the regulating device  10  is in the open position, each pushing arm  43  makes an angle α comprised between 10 and 20° with respect to the drive members  30 . Furthermore, the pushing arms  43  are able to rotate, so as to reach the configuration illustrated in  FIG. 3 b   . In that configuration, the pushing arms  43 , which initially make an angle comprised between 10 and 20° with respect to the drive members  30 , now make an angle comprised between 40 and 50° with respect to said drive members  30 . 
     Each drive member  30  further comprises two sliders  32 , connected to the drive rod  31  and situated on each side of said curtains  11 . Said sliders  32  are guided in slideways  52  fixed to the lateral beams of the frame  50  and parallel to said beams. In such a configuration, the sliders  32  are guided in translation in the slideways  52  in the direction Z. Advantageously, that allows the drive rods  31  to move along the same axis while remaining horizontal, namely parallel to the direction Y. 
     As in the preceding embodiments; said drive rods  31  are directly connected to the curtains  11 , so that any translational movement of said drive rods  31  in the direction Z induces a translational movement of said curtains  11  in the same direction. 
     As an alternative, said drive members  30  may be studs connected directly to corners of the curtains  11 . 
     The principle of closing of the curtains  11  is as follows. 
     When the actuator(s)  40  is (are) in operation, the pushing arms  43  effect a rotational movement about their axis (axes) of rotation. During this rotational movement, the pushing arms  43 , which initially make an angle comprised between 10 and 20° with respect to the direction Y, now make an angle comprised between 40 and 50°. The rotational movements of the pushing arms  43  cause the carriages  25  to slide along the drive rods  31  from a position P O  toward a position P P  and, at the same time, a translational movement of direction Z from, respectively, a position P CI1  toward a position P CF1  and a position P CI2  toward a position P CF2  opposed to the position P CF1  with respect to the axis passing through the dotted line P F -P F . 
     Incidentally, the drive rods  31 , guided in translation in the direction Z, notably by means of the sliders  32 , drive the curtains  11  in their opposing translational movements. As they move, the drive members  30  connected to the first curtain  11  guide said first curtain  11 , so that its proximal edge  11   a , initially situated in a first open position P O1 , moves toward a closed position P F  while remaining essentially horizontal. At the same time, said second curtain  11  is guided in translation from a second open position P O2 , opposed to the first open position P O1  with respect to the axis passing through the dotted line P F -P F , toward a closed position P F . 
     Because the two pushing arms  43  are driven simultaneously by the drive shaft  41 , the curtains  11  are guided symmetrically with respect to one another, so that the distance separating the two curtains  11 , notably the proximal edges  11   a  thereof, remains equal on either side of the dotted line P F -P F , throughout their movement. When the curtains  11  are in contact, or even overlapping, they therefore do not allow the passage of the flow F of air circulating perpendicular to the plane of extension of the curtains in the closed position. 
     Conversely, the curtains are able to return to their original position (as illustrated in  FIG. 3 a   ) by moving in a direction of opening/closing Z, for example when the actuator  40  is no longer in operation. Specifically, because the curtain tensioning means  54  continuously exert a force on the curtains  11 , said curtains  11  roll up again around their respective rolling-up/unrolling shaft  53  and the elements of said transmission system  20  and the drive members  30  return to their original position.