Abstract:
A heating and/or air-conditioning installation with a motor-driven fan unit has a motor driving a turbine, a speed control module and a volute housing the motor and forming an outlet channel for airflow at the periphery of the turbine. The speed control module is mounted at the periphery of the motor and has an electrical connector engaging a connector of the motor. It also has one or more walls of thermally conducting material and in contact with the outlet channel to cool the module.

Description:
FIELD OF THE INVENTION 
     The subject of the present invention is a heating and/or air-conditioning installation comprising a motor-driven fan unit including a motor, a module for varying the speed of the motor , a turbine driven by the motor, and a volute within which the motor is housed and defining an outlet channel for an airflow at the periphery of the turbine. 
     BACKGROUND OF THE INVENTION 
     In such an installation, the module for varying the speed of the motor must meet a certain number of constraints, particularly as regards the removal of the heat energy generated by the module, as well as relating to electromagnetic interference. For example, the use of a module of the pulse-width modulation type employs power-pulse switching operations which generate electromagnetic radiation, which is transported particularly by the connecting wires, downstream to the motor and upstream to the control electronics of the module and the power supply wires. The EMI electromagnetic interference standards limit the allowed radiation, which means that the modules, and particularly the modules with pulse-width modulation PWM, comprise filters, as does the motor. 
     It is certainly possible, as the U.S. Pat. No. 5,070,267 moreover teaches, to house the control module entirely within the motor, but this means designing the motor specifically, and there can the before be no question in such a case of using already existing standard motors. Moreover, implementing such integration poses not inconsiderable problems of cost. 
     It has been proposed, in addition, to house the module outside the motor, but this is accompanied by the existence of linking wires between the module and the motor which do not ease the solving of the problem of the electromagnetic interference EMI. 
     This EMI interference is generated by radiation from the linking wires which constitute antennae and/or from the power-supply cabling of the module, which can disturb electronic apparatus (car radio, etc.). 
     The object of the present invention is to provide a heating and/or air-conditioning installation which makes it possible at least partly to solve the abovementioned problems. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided a heating and/or air-conditioning installation comprising a motor-driven fan unit including a motor, a module for varying the speed of the motor, a turbine driven by the motor, and a volute within which the motor is housed and defining an outlet channel for an airflow at the periphery of the turbine, wherein the speed-variation module is mounted at the periphery of the motor and features an electrical connector plugged into a complementary connector of the motor, as well as at least one wall made of a thermally conducting material which is in communication with the outlet channel of the volute so as to cool the module. 
     This assembly, by virtue of a direct connection between the module and the motor, makes it possible to avoid electromagnetic interference being generated by wires for linking between the module and the motor, and, moreover, the mounting position makes it possible easily to put at least one cooling wall in contact with the air originating from the turbine or blower. 
     In particular, at least one said wall can be arranged in an aperture opening out into the outlet channel of the volute. The cooling can be enhanced by arranging several of these said walls in such a way as to form cooling fins. 
     It is advantageous for least one said wall to run along a wall of the said aperture formed in the volute and opening out into the outlet channel, this making it possible, in particular, to facilitate mounting by forming a reference surface which forms an end stop when the connector is at the end of connection travel. 
     Preferably, the said aperture forms part of a channel for cooling the motor, which takes in air from the airflow from the outlet channel of the volute. 
     The module may feature a face which comes to bear on one face of the volute which forms one side of the outlet channel. 
     The module may advantageously be of circular-sector shape, so as to match closely to the outer contour of the volute. 
     The components of the module are advantageously arranged in a casing featuring at least one part made of metal or loaded plastic. 
     It is advantageous for the casing to feature at least two compartments separated by at least one partition allowing thermal separation and/or isolation with regard to electromagnetic disturbances. In particular, a compartment may include at least one input choke of the module. 
     In one advantageous embodiment, an airflow channel is formed within the module, with an inlet which communicates with a first region of the outlet channel of the volute, and an outlet which communicates with a second region of the outlet channel of the volute, situated upstream of the first region with respect to the direction of flow of the airflow in the outlet channel. 
     In another advantageous embodiment, an airflow channel runs along the lower face of the module and communicates with the said outlet channel via a plurality of apertures, so as to pick up, from the outlet channel, an airflow which runs along the said lower face in order to cool the module. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
     FIG. 1 represents a module mounted on a volute, for which only the so-called lower half-volute is represented; 
     FIGS. 2 a,    2   b  and  2   c  represent a casing element of the module carrying the fins and which comes into contact with the volute. 
     FIG. 2 d  is a diagram representing the printed circuit mounted in the module; 
     FIG. 2 e  is a simplified diagram illustrating the protective filtering of the module and of the motor; 
     FIG. 3 represents a volute element, namely a lower half-volute, on which the module is intended to be mounted. 
     and FIGS. 4 a  and  4   b  represent the section BB and AA of a variant embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the various figures, like reference numerals refer to like parts. 
     Turning more particularly to FIGS. 1 and 3, the mounting of the module  9  onto the volute  1  is carried out in such a way as to plug a connector  160  of the module  9  through an aperture  8  of a volute element  2  (for example half-volute or motor support  2 ) into a corresponding connector of the motor M, and, in this mounted position, at least one wall  105  (FIGS. 2 a,    2   c  in particular) of a lower casing element  100  comes to be lodged in an aperture  7  of the volute element  2 , this aperture  7  opening out into an outlet channel  4  of the volute which extends around a turbine or blower from a start region  41  and flaring out progressively towards an outlet  42 . In particular, this aperture  7  can equally be used to cool the motor downstream of the cooling of the module. 
     The air supply to this aperture  7  is produced naturally under the effect of the dynamic pressure of the air which flows in the outlet channel  4 . It will be noted, as is apparent in FIGS. 1 and 3, that the module  9  consists of an upper casing  90  and of a lower casing  100  linked by fixings  93 ,  113 , and which are arranged in such a way as to come to bear on one face  5  of the volute which forms a platform which borders the outlet channel  4  surrounding the motor M. More particularly, the module  9  is housed in the vicinity of the start  41  of the outlet channel  4  and virtually in the first half of the angular space occupied by this channel. This arrangement is favourable to the extent that, on the one hand, there is no additional axial space required by the installation of the module  9  and, on the other hand, because this space situated around the motor M in the vicinity of the start  41  of the channel  4  is generally unused and can therefore be occupied without inconvenience. 
     As FIGS. 2 a  to  2   c  more particularly show, the lower part  100  of the casing  9  of the module features a bottom  101  which comes to bear on the platform-forming face  5  of the element  2  of the volute  1 , a concave inner face  103  at one end of which is situated a housing  102  for the connector, and at the other end of which is arranged the cooling element  104  featuring at least one cooling wall  105 , and additional fins  106  as the case may be. In the example represented, this wall  105  is situated at the end of the module  9  and runs along the face  71  of the aperture  7  in mounting position of the module when the connector  160  has been clipped fully into the complementary connector of the motor M. 
     The half-casing  100  also features spacers  120  allowing for the mounting of a printed circuit  170  represented diagrammatically in FIG. 2 d.  This circuit  170  features electrical power-supply contacts  175 , and various electrical components: self-inductive components, for example an input choke L 0 , capacitive components (C 5 , C 7 , C 9 , etc.), as well as transistors (T 1 , T 2 , T 3 ) and/or a thyristor THR. So as to avoid over-rapid thermal propagation from one element to the other, the casing advantageously includes at least two compartments  111  and  112  separated by one (or more) partitions  110 , which particularly makes it possible, as represented, to isolate the input choke L 0  arranged for this purpose in the compartment  111  which is juxtaposed with the exchanger  104  and which is separated by the partition  110  from the compartment  112  which carries the other components of the circuit. Moreover, the use of a metal partition  110  makes it possible to provide a certain electromagnetic immunity with regard to electromagnetic interference phenomena between the two compartments. 
     When the module  9  is mounted on the volute  1 , the lower face  180  of the half-casing  100  is in contact with the platform-forming wall  5 , the connector  160  is clipped into the corresponding connector of the motor and the wall or walls  105  and/or  106  are positioned in the aperture  7  so as to be traversed by the airflow of the channel  4 . End lugs  140 ,  150  make it possible to fix the casing  100  in place once it has been put in place. 
     The geometry adopted, of a circular-sectorshaped casing, allows simple mounting in 3 stages, namely, a phase of approach substantially parallel to the X axis so as to position the wall  105  above the aperture  7  and the connector  160  close to the complementary connector, a position of descent in the direction of the OZ axis in order to lower the wall  105  into the housing  7  and arrange the connector  160  in position alongside the complementary connector, and finally a phase of connection parallel to the X axis in order to plug the connector  160  into the complementary connector and arrange the wall  105  close to the wall  71  or in abutment on it. 
     In order to avoid vibration being transmitted to the card, the connector  160  of the module is advantageously decoupled from the card, for example by an intermediate gasket made of flexible elastomer. 
     Leaktightness can easily be achieved by having the apertures of the module co-operate with the apertures of the support via conventional sealing means such as lips, elastomer gaskets, etc. 
     The use of a direct connection between the module and the motor makes it possible, in the case of a module of the PWM type for which the power to be removed is of the order of 20 W (see FIG. 2 e ) to dispense with a capacitor C 0  at the motor M, connected in parallel between the ends of the chokes L &amp; L′, and, at the module, with a series choke L 1 . These two elements thus omitted are represented in dashed line in FIG. 2 e.    
     The cooling could be enhanced as required by making the air flow through the module itself in such a way that it directly bathes the components of the printed circuit. To that end, the module could be equipped with an air channel taking in air from the airflow in the aperture  7  and exhausting it into the channel  4  upstream in the direction of flow of the airflow. This counter-current flow is possible in fact, since the dynamic pressure increases in proportion with the distance from the inlet  41  of the channel  4  to its outlet  42 . 
     According to the variant represented in FIGS. 4 a  and  4   b,  the module  9  is raised by walls  193 ,  194 ,  195 ,  196  provided at their upper part with sealing means  197  so as to free a channel  190  which communicates with the outlet channel  4  through apertures  191  and  192  formed, for example, in the wall  5  of the volute (for example half-volute or motor support  2 ), and which allow an airflow to pass which runs along the lower wall  180  of the module  9 , possibly equipped with fins, not represented, so as to provide cooling of the module. The channel  190  thus takes in the air from the airflow of the channel  4  through at least one aperture and exhausts it into the channel  4  through at least one aperture.