Patent Publication Number: US-9835175-B2

Title: Ventilation device

Description:
RELATED APPLICATIONS 
     This application is the National Stage of International Patent Application No. PCT/EP2013/056150, filed on Mar. 22, 2013, which claims priority to and all the advantages of French Patent Application No. FR 12/52593, filed on Mar. 22, 2012, the content of which is incorporated herein by reference. 
     The invention relates to a ventilation device comprising a fan propeller and a driving motor of the propeller. 
     A fan propeller traditionally comprises a central hub and blades extending radially from the hub to the outside of the propeller. 
     Such a propeller is notably used in the cooling of the driving engine of a motor vehicle. In this case, the propeller may be placed upstream or downstream of a heat exchanger, namely a radiator for cooling the driving engine. 
     According to a known configuration, the central hub of the propeller comprises a frontal wall and a substantially cylindrical peripheral skirt extending from the frontal wall and to which the blades of the propeller are connected. 
     The frontal wall has a substantially annular form and makes it possible for example to fix the electric motor that drives the rotation of the propeller. 
     This electric motor is mounted coaxial to the hub of the propeller. 
     The motor can have an internal rotor and the central hub is generally linked to the motor drive shaft. 
     When the motor has an external rotor in contact with the central hub, the fastening is generally done by screwing on the frontal wall of the hub of the propeller. In practice, according to one known solution, three screwing means are provided in proximity to the center of the frontal wall of the hub. 
     However, this solution requires a significant quantity of material to define the frontal wall of the hub. 
     Moreover, the current trend is to reduce the spaces or volumes under the engine hood. It is therefore necessary to propose ventilation devices that are increasingly more compact, notably in the axial bulk of such devices. 
     Now, in the known solution with screwing means on the frontal wall of the central hub, the thickness of these screwing means is added to the axial bulk of the ventilation device. 
     The aim of the invention is to at least partly mitigate these drawbacks of the prior art by proposing a ventilation device, that enables the hub to be fastened to the motor to drive the propeller in rotation, while offering an axially compact solution. 
     To this end, the subject of the invention is a ventilation device comprising a fan propeller and a motor with external rotor for driving said propeller, said propeller comprising a central hub having a frontal wall and an internal lateral wall defining an accommodating housing for the external rotor, and the external rotor having a front part and a lateral wall arranged bearing against the internal lateral wall of the central hub, characterized in that said device further comprises means for snap-fitting the external rotor to the central hub that are borne on the one hand by the central hub and on the other hand by the external rotor. 
     The terms “upstream” and “downstream”, “front” and “rear” here refer to the direction of flow of the flow of air. 
     Thus, the frontal wall of the central hub can be open to receive the front part of the external rotor of the motor in a flush manner. It is no longer necessary to provide a significant quantity of material to define the frontal wall of the hub in as much as the fastening between the central hub and the motor is no longer done at this point. 
     On the contrary, the fastening means are designed in such a way that the internal lateral wall of the hub and the lateral wall of the external rotor are clamped together. 
     There is therefore no additional thickness in the axial bulk of the ventilation device due to the fastening means. 
     This system therefore makes it possible to minimize the number of components and simplifies the assembly operations. 
     Said ventilation device can further comprise one or more of the following features, taken separately or in combination:
         the snap-fitting means comprise a ring mounted on the external rotor and provided with a plurality of elastically deformable clamps, said clamps comprising, respectively, a first branch arranged bearing against the lateral wall of the external rotor and a second branch arranged bearing against the internal lateral wall of the central hub, so as to clamp together said rotor and said hub;   the external rotor comprises a plurality of magnets and said clamps are arranged between said magnets;   the central hub comprises a plurality of accommodating housings for said second branches;   said housings of the central hub respectively comprise at least one snap-fitting hook and said second branches respectively comprise at least one orifice complementing said hook in which said hook is engaged;   said second branches respectively comprise at least one snap-fitting hook and said housings of the central hub respectively comprise at least one orifice complementing said hook in which said hook is engaged;   said second branches respectively have a substantially bent-back end;   the frontal wall of the central hub has a central opening receiving the front part of the external rotor, and the frontal wall of the central hub and the front part of the external rotor are flush;   said device comprises additional means for securing the motor and said hub in rotation, borne on the one hand by the external rotor and on the other hand by said hub;   the frontal wall of said hub comprises radial protuberances that engage with complementary notches provided on the front part of said rotor;   said hub has a predefined number of cylindrical bosses and the front part of the external rotor has complementary emergent holes into which said cylindrical bosses are inserted.       

    
    
     
       Other features and advantages of the invention will become more clearly apparent on reading the following description, given as an illustrative and nonlimiting example, and the attached drawings in which: 
         FIG. 1  is a front view of a ventilation device comprising a fan propeller and a driving motor, 
         FIG. 2  is a perspective view of  FIG. 1 , 
         FIG. 3  is a perspective view of the downstream face of the ventilation device in the direction of flow of the flow of air, 
         FIG. 4 a    is a front view of the driving motor of the ventilation device of  FIGS. 1 to 3 , 
         FIG. 4 b    is a perspective view of  FIG. 4   a,    
         FIG. 5  is a view in cross section along an axis I-I of  FIG. 1 , 
         FIG. 6  is a perspective view of the upstream face of the propeller of the ventilation device of  FIG. 2  in the direction of flow of the flow of air, 
         FIG. 7  is a perspective view of the downstream face in the direction of flow of the flow of air of the propeller of  FIG. 5 , 
         FIG. 8  is a perspective view of a ring for attaching the rotor of the motor to the hub of the propeller, and 
         FIG. 9  is an enlarged view of a portion B of  FIG. 8  representing a clamp of the ring of  FIG. 8  cooperating with a snap-fitting hook of the central hub of the propeller. 
     
    
    
     In these figures, the elements that are substantially identical bear the same references. 
     With reference to  FIGS. 1 to 3 , the invention relates to a ventilation device  1  comprising a fan propeller  3  and a driving motor  5  for the propeller  3 . 
     It is notably a ventilation device  1  for a cooling module of a motor vehicle engine block (not represented). Such a cooling module generally comprises a heat exchanger such as a cooling radiator. The propeller  3  can be arranged either in front of or behind this cooling radiator. 
     The driving motor  5 , more visible in  FIGS. 4 a  and 4 b   , is an electric motor, which comprises, according to the embodiment described, a stator  7   a  and an external rotor  7   b.    
     The stator  7   a  has at least one winding and the rotor  7   b  comprises one or more magnets. The rotor  7   b  comprises, for example, a number of magnets distributed over the circumference of the rotor  7   b.  The magnets are, according to the embodiment described, permanent magnets. 
     The stator  7   a  has fixing lugs  8  for fastening to a support (not represented). 
     The external rotor  7   b  is received in the central hub  11  of the propeller  3  (see  FIGS. 1  to  3 ). A complementarity of form is therefore provided between the external rotor  7   b  and the central hub  11  of the propeller  3  for the rotational driving. 
     Referring once again to  FIG. 4 b   , the external rotor  7   b  has a front part  9  and a rear part  9 ′ opposite the front part  9 . The terms “front” and “rear” are used with reference to the direction of flow of the flow of air. 
     The front  9  and rear  9 ′ parts are linked together by a substantially cylindrical lateral wall  9 ″. 
     According to the embodiment described, the lateral wall  9 ″ of the external rotor  7   b  has an external face intended to be in contact with the central hub  11  during assembly, and an opposing internal face oriented toward the interior of the rotor  7   b.    
     The front part  9  of the rotor  7   b  has through openings  10 , more visible in  FIG. 4 a   . The agitated flow of air passes through the openings  10  making it possible to cool the motor  5 . 
     These openings  10  are, according to the embodiment represented, of substantially oblong form. 
     The openings  10  are for example evenly distributed. 
     The propeller  3  is driven in rotation about an axis of rotation A (see  FIG. 5 ). 
     The direction of rotation of the propeller  3  is schematically represented by the arrow F in  FIGS. 1 to 3 . 
     When the propeller  3  is driven in rotation by the motor  5 , the propeller  3  agitates the air which passes through it and creates a flow of air from upstream to downstream by communicating its rotational energy to it. 
     This propeller  3  is, for example, produced by plastic injection molding. The mold stripping of the propeller  3  can be done in an axial direction. 
     Referring to  FIGS. 6 and 7 , the propeller  3  comprises:
         a central hub  11 ,   a plurality of blades  13  which extend radially from the central hub  11 , and   a peripheral shell  15  to which the free ends of the blades  13  are connected.       

     The central hub  11  is hollow and is also called “bowl”. 
     This central hub  11  is for example produced by molding at the same time as the rest of the propeller  3 . 
     The central hub  11  is driven in rotation by the rotor  7   b.    
     The rotational securing between the central hub  11  and the rotor  7   b  is for example obtained by complementarity of form between the central hub  11  and the rotor  7   b.    
     This central hub  11  has:
         an upstream frontal wall  17  having a central opening  19 ,   an internal lateral wall  21 , and   a peripheral skirt  23 .       

     In the present description, the terms “upstream” and “downstream” refer to the direction of flow of the flow of air produced by the rotation of the propeller  3 . 
     The frontal wall  17  has a substantially annular form. This frontal wall  17  therefore has an internal first diameter D 1  which corresponds to the diameter of the opening  19 , and an external second diameter D 2 . 
     The frontal wall  17  is arranged flush with the front part  9  of the external rotor  7   b.    
     The peripheral skirt  23  has a substantially cylindrical form. It extends downstream from the frontal wall  17 . 
     The blades  13  are connected to this peripheral skirt  23 . 
     The frontal wall  17  and the peripheral skirt  23  are for example linked together by a rounded section  25 . 
     Similarly, the internal lateral wall  21  extends downstream from the frontal wall  17 . This internal lateral wall  21  is substantially cylindrical and delimits the opening  19  of the frontal wall  17 . The internal lateral wall  21  defines an accommodating housing for the driving motor  5  (see  FIGS. 2, 3 and 6 and 7 ), more specifically for the external rotor  7   b  of the motor  5 . 
     In particular, a complementarity of form is provided between the internal lateral wall  21  of the central hub  11  and the external rotor  7   b  of the motor  5 . 
     This internal lateral wall  21  has an external face and an internal face opposite the external face. The external face of the internal lateral wall  21  is intended to be in contact with the external face of the lateral wall  9 ″ of the external rotor  7   b  on assembly. The internal face of the internal lateral wall is arranged facing the peripheral skirt  23  of the hub  11 . 
     The driving motor  5  is generally mounted coaxial to the central hub  11  of the propeller  3 , as illustrated by  FIGS. 1 to 3 . 
     Once the motor  5  is assembled with the central hub  11 , the frontal wall  17  of the central hub  11  is bearing against the front part  9  of the rotor  7   b.    
     Furthermore, in order to ensure the mechanical secure attachment between the motor  5  and the hub  11 , the ventilation device  1  comprises means for fastening the central hub  11  to the rotor  7   b.    
     These fastening means are borne on the one hand by the central hub  11  and on the other hand by the external rotor. 
     They are, according to the embodiment described, snap-fitting means  27 , more visible in  FIGS. 5, 8 and 9 , which make it possible to attach together the internal lateral wall  21  of the central hub  11  and the lateral wall  9 ″ of the external rotor  7   b.    
     The snap-fitting means  27  are for example borne by the rotor  7   b  and suitable for cooperating with the central hub  11 . 
     More specifically, according to the embodiment illustrated in  FIGS. 5 and 9 , the snap-fitting means  27  are borne by the rotor  7   b  and cooperate with complementary means borne by the internal cylindrical wall  21  of the central hub  11 . 
     As can be seen better in  FIGS. 4 a , 4 b    and  8 , the snap-fitting means  27  comprise, according to the embodiment illustrated, a ring  29  mounted on the external rotor  7   b;  this ring  29  is provided with a plurality of elastically deformable clamps  31 . 
     These clamps  31  are, for example, arranged between the magnets of the rotor  7   b.  This arrangement allows for the angular immobilization of the clamps  31 . 
     More specifically, the ring  29  is mounted on the rear part  9 ′ of the rotor  7   b.    
     The clamps  31  can be evenly distributed by a predefined angular pitch, as in the example illustrated in  FIG. 8 . 
     Each clamp  31  comprises a first branch  33   a  and a second branch  33   b.    
     On assembly of the motor  5  and the central hub  11 , the first branch  33   a  of a clamp  31  is arranged bearing against the external rotor  7   b,  more specifically bearing against the internal face of its lateral wall  9 ″ ( FIGS. 3, 4   b  and  9 ). 
     For its part, the second branch  33   b  is arranged bearing against the central hub  11 . 
     More specifically, a second branch  33   b  of a clamp  31  is for example received in a complementary housing  35  of the central hub  11 . The hub  11  therefore comprises for this purpose a plurality of complementary housings  35  to receive the second branches  33   b  of the plurality of clamps  31 . 
     These housings  35  are, according to the example illustrated, defined in the internal lateral wall  21  of the central hub  11 . 
     The clamps  31  thus make it possible to hold together the external rotor  7   b  and the central hub  11  by clamping. 
     There is therefore no need to provide a significant quantity of material for the frontal wall  17  of the central hub  11  because the securing is not done at this frontal wall  17  but at the lateral walls  21  and  9 ″ respectively of the central hub  11  and of the external rotor  7   b.  This frontal wall  17  can thus have a central opening  19  that is larger than in certain solutions known from the prior art. 
     Furthermore, the snap-fitting means are, according to the embodiment described, borne on the one hand by the central hub  11  and on the other hand by the clamps  31 . 
     According to the example illustrated in  FIG. 9 , the housings  35  of the hub  11  respectively comprise at least one snap-fitting hook  37  and complementing this (see  FIGS. 8 and 9 ), the second branches  33   b  of the clamps  31  respectively comprise at least one orifice  39  in which an associated hook  37  engages. 
     The cooperation between a snap-fitting hook  37  and an orifice  39  is more visible in  FIG. 9  showing a close-up portion B of the cross-sectional view of  FIG. 5 . 
     The snap-fitting of the hook  37  in an associated orifice  39  makes it possible to secure the rotor  7   b  to the central hub  11  and to axially block the central hub  11  of the propeller  1  relative to the rotor  7   b.    
     As an alternative, the snap-fitting hooks  37  can be borne by the second branches  33   b  of the clamps  31  and the housings  35  can comprise a complementary orifice in which the hook  37  is engaged. 
     Furthermore, the second branches  33   b  of the clamps  31  can respectively have a substantially bent-back end  41 . This bent-back end  41  facilitates the insertion of the second branch  33   b  into the corresponding housing  35 . 
     Furthermore, referring to  FIGS. 1, 2 and 9 , it is possible to provide, on the frontal wall  17  of the central hub  11 , one or more radial protuberances  43  oriented toward the external rotor  7   b.    
     Thus, according to the example illustrated in the figures, the central hub  11  has a plurality of protuberances  43 . The protuberances  43  extend radially relative to the axis of rotation A of the propeller  3  and are oriented toward the rotor  7   b.    
     A protuberance  43  engages a complementary notch  45  provided on the front part  9  of the rotor  7   b.  The rotor  7   b  therefore has, complementing the protuberances  43 , a number of associated complementary notches  45 . The notches  45  can be seen better in  FIGS. 4 a    and  4   b.    
     The cooperation between the protuberances  43  and the notches  45  completes the rotational securing of the central hub  11  to the rotor  7   b.    
     A reverse construction can be envisaged in which it is the rotor  7   b  which has one or more protuberances suitable for engaging in an associated notch provided on the frontal wall  17  of the central hub  11 . 
     Any other addition for securing the rotation of the central hub  11  and the motor  5  can be envisaged. 
     As a variant or as an alternative, the central hub  11  can have a predefined number of cylindrical bosses (not represented) and the front part  9  of the rotor  7   b  can have complementary emergent holes into which these cylindrical bosses are inserted. 
     Moreover, the central hub  11  can, furthermore, have internal ribs  47 , visible in FIGS.  3  and  7 . 
     These internal ribs  47  extend radially relative to the axis of rotation A of the propeller  3  opposite the blades  13 . 
     These internal ribs  47  make it possible to rigidify the central hub  11 . 
     These internal ribs  47  can also be used to force the ventilation into the central hub  11  so as to cool the driving motor  5  driving the propeller  3 . 
     In practice, when the propeller  3  is driven in rotation, the internal ribs  47  agitate the air present inside the central hub  11 . This air is therefore discharged toward the outside of the central hub  11  downstream, and, in addition, the aerodynamic force induced by the internal ribs  47  makes it possible to suck air into the driving motor  5  before discharging it also toward the outside of the central hub  11 . 
     Furthermore, the internal ribs  47  can be evenly spaced at a predefined angular pitch. 
     Obviously, the internal ribs  47  may not be evenly spaced. 
     Moreover, the internal ribs  47  are for example produced by plastic injection molding in the same mold as the rest of the propeller  3 . 
     In particular, the internal ribs  47  can be produced in a single piece with the central hub  11  by molding. The mold striping can still be done in an axial direction. 
     As a variant, the internal ribs  47  can be produced separately from the rest of the propeller  3  and then assembled with the propeller  3 . Any means of assembling the internal ribs  47  with the central hub  11  can be envisaged. 
     With respect to the blades  13 , they extend from the peripheral skirt  23  of the central hub  11  to the peripheral shell  15  (see  FIGS. 1 to 3 and 6 and 7 ). 
     These blades  13  are generally identical. 
     The blades  13  respectively have a leading edge  49  which comes first into contact with the flow of air upon the rotation of the propeller  3 , and a trailing edge  51  opposite the leading edge  49 . 
     For its part, the shell  15  has a cylindrical wall  53 , to which the ends of the blades  13  are connected, and which is continued, with a flare  55  (see  FIG. 7 ). 
     Thus, the propeller  3  is clipped onto the external rotor  7   b  of the motor  5  via snap-fitting means  27  that are directly assembled on the external rotor  7   b.    
     In practice, the rotor  7   b  is equipped with one or more clamps  31  secured to the rotor  7   b  via the ring  29  mounted on the external rotor  7   b.    
     The central hub  11  of the propeller  3  is centered on the external diameter of the rotor  7   b  and is inserted into the clamps  31 , the snap-fitting means on the clamps  31  lock the position of the propeller  3  and also allow for the rotational driving of the central hub  11  and therefore of the propeller  3 , by the external rotor  7   b  of the motor  5 . 
     This assembly makes it possible to have a compact solution. 
     In practice, the central hub  11  of the propeller  1  is flush with the frame of the motor  5 . There is not additional thickness, as for example according to a prior art solution in which the fastening is done for example by screwing onto the frontal wall. This system therefore makes it possible to minimize the number of components and simplifies the assembly operations, in particular by comparison with the screwing-based prior art solution.