Abstract:
A miniature fan arrangement has a fan ( 10 ) including an electronically commutated drive motor ( 21 ), a first circuit board ( 52 ) associated with said motor, and a fan housing ( 30 ). The fan also has a mounting part arranged radially outside the fan housing ( 30 ), and has a membrane ( 32 ), made of an elastic material, that elastically connects the fan housing ( 30 ) and the mounting part ( 34 ) to one another. A second circuit board ( 54 ) is arranged between the mounting part ( 34 ) and the fan housing ( 30 ) and is electrically connected to the first circuit board ( 52 ). The structure provides space for additional motor control components, particularly in small-sized motors.

Description:
CROSS-REFERENCE 
       [0001]    This application claims priority from our German application 20 2008005 917.8, filed 21 Apr. 2008, the entire content of which is incorporated by reference. The application refers to commonly-assigned U.S. Ser. No. 10/884,697, now U.S. Pat. No. 7,189,053, WINKLER &amp; METZGER. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a miniature fan arrangement and, in particular, to a miniature fan arrangement having a vibration-damping suspension system. 
       BACKGROUND 
       [0003]    EP 1 498 613 A2 and U.S. Pat. No. 7,189,053, WINKLER &amp; METZGER (commonly assigned with the present application) disclose an arrangement in which, in order to reduce vibrations generated by a fan, the fan is suspended m a mounting frame using a flexible part. This is advantageous in particular when the vibrations generated by the fan can be perceived as irritating, for example when a vehicle seat or items of equipment are being ventilated. 
         [0004]    In numerous applications, miniature or subminiature fans having housing dimensions of 20 to 60 mm on a side are used to create such fan arrangements. These fans must often be equipped, in an application-specific manner, with an expanded electronic control and protection system that is necessary for cooling purposes or, in combination with a small heating system, for heating purposes, for example in automobiles, trains, aircraft, control cabinets, switching cabinets, and IT electronics cabinets. In addition, this electronic system can also be designed to operate the fan alternatively for blowing or for suction. Because of the very small dimensions of miniature and subminiature fans, however, the expanded electronic control and protection system usually cannot be arranged, or can be arranged only partly, on the circuit board associated with the fan. 
       SUMMARY OF THE INVENTION 
       [0005]    It is therefore an object of the present invention to make available a novel miniature fan arrangement with enough space for more components. 
         [0006]    This object is achieved by a miniature fan arrangement having a first circuit board, a fan housing, a mounting part arranged radially outside the fan housing, a membrane which elastically connects the fan housing and the mounting part to each other, and a second circuit board, electrically connected to the first circuit board, arranged in a region between the mounting part and the fan housing. 
         [0007]    An additional component placement surface is made available here by the use of a second circuit board that is arranged radially inside an outer mounting part and outside a fan housing of the fan. The dimensions of the second circuit board are preferably determined as a function of the dimensions of the fan housing and of the mounting part, so that their dimensions can continue to remain small. 
         [0008]    This object can also be achieved by a miniature fan arrangement having a fan housing, an electronically commutated drive motor, a first circuit board arranged inside the fan housing, a second circuit board arranged outside the fan housing and electrically connected to the first circuit board, a mounting part arranged outside the fan housing, and a membrane elastically connecting the fan housing and the mounting part to each other. Here the additional component placement surface is made available by the use of a second circuit board that is arranged radially inside the fan housing. 
         [0009]    It is thereby possible, even in the case of miniature and subminiature fans having a very small physical size, to implement an expanded electronic control system in simple fashion with no impairment of air output and air pressure buildup or of the fan&#39;s output. This electronic control system can comprise protection against incorrectly polarized connection, overvoltage protection, and/or stall protection. In addition, the fact that the additional component placement surface is made available creates room for a control system using pulse width modulation (PWM), for an analog and/or output-based control system, and for LAN-(Local Area Network) or CAN-(Controller Area Network) bus control systems. 
     
    
     
       BRIEF FIGURE DESCRIPTION 
         [0010]    Further details and advantageous refinements of the invention are evident from the exemplifying embodiments, in no way to be understood as a limitation of the invention, that are described below and depicted in the drawings, in which: 
           [0011]      FIG. 1  is a perspective view of the discharge side of a fan arrangement in accordance with a first embodiment; 
           [0012]      FIG. 2  is a perspective view of the suction side of the fan arrangement of  FIG. 1 ; 
           [0013]      FIG. 3  is a side view of the fan arrangement of  FIG. 1 ; 
           [0014]      FIG. 4  is an enlarged side view of the strain relief apparatus of  FIG. 3 ; 
           [0015]      FIG. 5  is a plan view of the discharge side of the fan arrangement of  FIG. 1 ; 
           [0016]      FIG. 5A  is a depiction of  FIG. 5  at actual size, i.e. at 1:1 scale;  FIG. 6  is a plan view of the suction side of the fan arrangement of  FIG. 1 ; 
           [0017]      FIG. 1  is a sectioned view of the fan arrangement of  FIG. 1 , looking in the direction of line VII-VII of  FIG. 5 ; 
           [0018]      FIG. 8  is a sectioned view of the fan arrangement of  FIG. 1 , looking in the direction of line VIII-VIII of  FIG. 5 ; 
           [0019]      FIG. 9  is an enlarged view of detail IX of  FIG. 8 ; 
           [0020]      FIG. 10  is an enlarged view of detail X of  FIG. 8 ; 
           [0021]      FIG. 11  is a perspective view of the discharge side of a fan arrangement in accordance with a second embodiment; 
           [0022]      FIG. 12  is a sectioned view of the fan arrangement of  FIG. 11 , looking in the direction of line XII-XII of  FIG. 11 ; and 
           [0023]      FIG. 13  is an enlarged view of detail XIII of  FIG. 12 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    In the description that follows, the terms “left,” “right,” “front,” “rear,” “upper,” and “lower” refer to the particular figure of the drawings, and can vary from one figure to the next as a function of a particular orientation (portrait or landscape) that is selected. Identical or identically functioning parts are labeled with the same reference characters in the various figures, and usually are described only once. 
         [0025]      FIG. 1  shows a first embodiment of a fan arrangement  100  having a fan  10  and a mounting part  34 . Mounting part  34  has mounting flanges  34 ′,  34 ″,  34 ′″ for mounting the fan arrangement  100 , which arrangement can be bolted, riveted, adhesively bonded, or welded via mounting flanges  34 ′  34 ″,  34 ′″. Alternatively, mounting part  34  can itself be directly foam-embedded into wall foams, foam cushions, foam seat backs, etc. 
         [0026]    Fan  10  has a fan housing  30  in which a fan wheel  18  is arranged rotatably about a rotation axis  23  ( FIG. 7 ) that extends along the longitudinal axis of fan housing  30 . When fan  10  is in operation, fan wheel  18  delivers air in the direction of an arrow  98  ( FIGS. 1 ,  7 ) from a suction side  12  to a discharge side  14  of fan  10 , and has fan blades  26 ′ to  26 ″ whose shape is adapted to the shape of the inner side of fan housing  30 . 
         [0027]    As described in  FIG. 2 , fan housing  30  is suspended via a vibration-damping suspension system  32  ( FIGS. 2 ,  7 ,  8 ) in mounting part  34 , which is arranged radially outside fan housing  30 . Suspension system  32  serves to reduce vibrations and noise emissions that occur during the operation of fan  10 . 
         [0028]    Fan  10  has a motor  21  ( FIGS. 7 to 9 ) to drive its fan wheel  18 , which motor  21  is preferably implemented as an electronically commutated external-rotor motor. It has a rotor cup  25  ( FIGS. 2 ,  7 ,  8 ) on which fan wheel  18  is mounted. A mounting flange  38 , which is provided on a motor retaining tray  85  and is joined via struts  29 ′ to  29 ′″ to fan housing  30 , serves for the installation of motor  21  in fan housing  30 . 
         [0029]    Motor  21  has associated with it a first circuit board  52  for the reception of components of the motor electronics, which first circuit board  52  is arranged inside fan housing  30 . Said board is connected via flexible connector leads  62 ,  64  ( FIG. 1 ) to a second circuit board  54  that is provided as an additional component placement surface for an expanded electronic control and protection system. 
         [0030]    According to a first embodiment, second circuit board  54  is arranged radially inside mounting part  34  and radially outside fan housing  30 . The dimensions of second circuit board  54  are preferably determined as a function of the dimensions of fan housing  30  and of mounting part  34 . 
         [0031]    In  FIG. 1  fan housing  30  is implemented, by way of example, in a tubular shape and second circuit board  54  is arranged annularly around the tubular fan housing  30 . Second circuit board  54  can be provided, in this context, either in the region of suction side  12  or in the region of discharge side  14  of fan  10 . 
         [0032]    Be it noted that the use of a single second circuit board  54  that is arranged m the region of suction side  12  or discharge side  14  of fan  10  serves merely as an example for illustration of an exemplifying embodiment of the invention. Various modifications and variants are possible without changing the manner of operation of fan arrangement  100  according to the present invention. For example, second circuit board  54  can be provided on suction side  12  of fan  10 , and a third circuit board is arranged in the region of the latter&#39;s discharge side  14 , the second and third circuit board being, for example, interconnected in electrically conductive fashion. 
         [0033]    Provided between second circuit board  54  and fan housing  30  is at least one cutout  39  that, when discharge side  14  of fan  10  is closed off, enables a return flow (from discharge side  14  to suction side  12 ) of air delivered by fan wheel  18 . Cutout  39  is implemented in  FIG. 1  as an annular gap between second circuit board  54  and fan housing  30 . 
         [0034]    Provided in  FIG. 1  for the mounting of second circuit board  54  in mounting part  34  are, by way of example, three mounting elements  82 ′,  82 ″,  82 ′″ that are implemented, for example, as radially resilient latching tongues on inner side  36  of mounting part  34 . Upon installation of second circuit board  54 , these are inserted from discharge side  14  (in  FIG. 1 ) into mounting part  34 , latching tongues  82 ′,  82 ″,  82 ′″ first being bent radially outward from a predefined starting position so as then, after the insertion of second circuit board  54 , to spring back into their starting position and latch-mount circuit board  54 . In order to ensure correct assembly of second circuit board  54 , the latter preferably has a guide groove  97  that, upon insertion into mounting part  34 , is guided along a guide projection  99  provided on inner side  36  of mounting part  34 . 
         [0035]    After assembly, second circuit board  54  can be connected via leads  62 ,  64  to first circuit board  52 , for example by soldering. For delivery of an operating voltage for motor  21 , second circuit board  54  is furthermore electrically connected, e.g. once again by soldering, to a flexible voltage supply lead  90  that comprises two leads  91 ,  92 . In many cases additional leads are provided, for example for a tacho signal or an alarm signal. 
         [0036]    According to an embodiment of the invention, a strain relief apparatus  70  for flexible voltage supply lead  90  is provided on mounting part  34 . Said apparatus has at least one securing hook-formed post  71 ′,  71 ″, at least one winding post  72 ′,  72 ″, and at least one hooking post  73 ′,  73 ″. Securing hook-formed post  71 ′,  71 ″ serves to secure lead  90 , which is then guided from there, around winding post  72 ′,  72 ″, to hooking post  73 ′,  73 ″. At hooking post  73 ′,  73 ″, lead  90  is wound at least once around the post&#39;s entire outer periphery and then guided to circuit board  54  (see  FIGS. 1 and 3 ). The hook of hooking post  73 ′,  73 ″ prevents lead  90  from slipping out. Because of the friction occurring between securing hook-formed post  71 ′,  71 ″, winding post  72 ′,  72 ″, hooking post  73 ′,  73 ″, and lead  90  in the context of tensile force on lead  90 , lead  90  is held securely in strain relief apparatus  70  so that its electrical connection to second circuit board  54  is protected from damage or destruction due to tensile force. 
         [0037]    As is evident from  FIG. 1 , a separate strain relief apparatus can be provided for each lead  91 ,  92  of voltage supply lead  90 . Correspondingly, a securing hook-formed post  71 ′, a winding post  72 ′, and a hooking post  73 ′ for lead  91 , and a securing hook-formed post  71 ″, a winding post  72 ″, and a hooking post  73 ″ for lead  92 , are provided in  FIG. 1 . 
         [0038]      FIG. 2  shows suction side  12  of fan arrangement  100  of  FIG. 1 .  FIG. 2  illustrates latching tongue  62 ′″ provided on mounting part  34 , as well as vibration-damping suspension system  32 .  FIG. 2  further shows bracing elements  84 ′,  84 ″,  84 ′″,  84 ′″ for bracing second Circuit board  54  ( FIG. 1 ). 
         [0039]    According to an embodiment, vibration-damping suspension system  32  is a membrane or diaphragm, made of an elastic material, that elastically joins fan housing  30  and mounting part  34  to one another. Membrane  32  is made, for example, of a plastic or an elastomer and implemented as a direct connection between mounting part  34  and fan housing  30 . Membrane  32  can be joined in positive and/or materially connected fashion to fan housing  30  and/or to mounting part  34 . Membrane  32  is joined almost entirely or completely to fan housing  30  over the latter&#39;s entire outer periphery. The membrane is joined almost entirely or completely to mounting part  34  on its entire inner side  36 . 
         [0040]    As shown in  FIG. 2 , membrane  32  has six openings  33 ′,  33 ″,  33 ′″,  33 ″,  33 ′,  33   v . These serve, in the event of a closure of discharge side  14  of fan  10 , to enable a return flow (from discharge side  14  to suction side  12 ) of air delivered by fan wheel  18 . 
         [0041]    A suitable membrane for suspension of a fan housing in a mounting part is described in EP 1 498 613 A2 and corresponding U.S. Pat. No. 7,189,053, WINKLER &amp; METZGER (US attorney docket 870-003-176), to which reference is expressly made here. A more detailed description of membrane  32  is therefore omitted. 
         [0042]    Bracing elements  84 ′,  84 ″,  84 ′″,  84   −v  are implemented, according to an embodiment, as axially resilient support members on inner side  36  of mounting port  34 . Circuit board  54 , is supported resiliently on them after being installed in mounting part  34 , as described below with reference to  FIG. 7 . 
         [0043]      FIG. 3  is a side view of fan arrangement  100  of  FIG. 1  with strain relief apparatus  70  and resilient latching tongues  82 ″,  82 ′″ provided on mounting part  34 . 
         [0044]      FIG. 4  is a greatly enlarged view (5:1 scale) of strain relief apparatus  70  of  FIG. 3 .  FIG. 4  illustrates leads  91  and  92  that are respectively secured in securing hook-formed posts  71 ′,  71 ″, guided around winding posts  72 ′,  72 ″, and wound at least once around the entire outer periphery of hooking posts  73 ′,  73 ″. 
         [0045]      FIG. 5  is a plan view of discharge side  14  of fan arrangement  100  of  FIG. 1 .  FIG. 5  illustrates the latch-mounting of second circuit board  54 , having the radially resilient latching tongues  82 ′,  82 ″,  82 ′″, in mounting part  34 . 
         [0046]      FIG. 5A  shows  FIG. 5  at actual size, i.e. at 1:1 scale. 
         [0047]      FIG. 6  is a plan view of suction side  12  of fan arrangement  100  of  FIG. 1 . Membrane  32  is, by way of example, joined positively to fan housing  30  and to mounting part  34 . FIG. illustrates the six openings  33 ′,  33 ″,  33 ′″,  33 ,  33   v ,  33  provided in membrane  32 , and the resilient support members  84 ′,  84 ″,  84 ′″,  84 ,  84   v ,  84 . 
         [0048]      FIG. 7  is a sectioned view of fan arrangement  100  of  FIG. 1 , and illustrates membrane  32  joined in positive and materially connected fashion to fan housing  30  and to mounting part  34 , as well as the resilient support members  84 ″,  84   v  provided on mounting part  34 , on which members second circuit board  54  is supported. 
         [0049]    The electronically commutated drive motor  21  has a stator arrangement  83  having claw pole laminations  87 , an external rotor  88 , and a motor retaining tray  85  equipped with mounting flange  38 . Rotor  88  comprises rotor cup  25  on which fan wheel  18  is mounted, as well as a rotor shaft  96  that is journaled in a bearing arrangement  60  rotatably about rotation axis  23 . 
         [0050]      FIG. 8  is a sectioned view of fan arrangement  100  of  FIG. 1 .  FIG. 8  illustrates the mounting of second circuit board  54  in mounting part  34 , and the connection of electrical connector lead  64  to first and second circuit boards  52  and  54 , respectively. 
         [0051]    Second circuit board  54  is supported with its lower side  54 ′ on resilient support members  84 ″,  84 , and is latch-mounted on its upper side  54 ″. Latching tongue  82 ′ has for this purpose a latching hook  95  that latches in on upper side  54 ″ of circuit board  54 . 
         [0052]    Provided on this upper side  54 ″ is an electrical terminal  64 ′ on which is mounted one end of connector lead  64 , the other end of which is connected to an electrical terminal  64 ″ provided on first circuit board  52 . The length of connector lead  64  is selected in consideration of the resilient travel of membrane  32 , in order to prevent damage to or destruction of the electrical connection between circuit boards  52 ,  54  during the operation of fan  10 , for example due to detachment of lead  64 . 
         [0053]      FIG. 9  is a greatly enlarged view of drive motor  21  of  FIG. 8 , and shows lead  64  connected to electrical terminal  64 ″ that is provided on first circuit board  52 . 
         [0054]      FIG. 10  is a greatly enlarged view of the resilient latching tongue  82 ′ of  FIG. 8  which, with its latching hook  95  latched in on upper side  54 ″ of circuit board  54 , latch-mounts circuit board  54  in mounting part  34 . There exists between circuit board  54  and inner side  36  of mounting part  34  a clearance D that compensates for possible movements of second circuit board  54  during the operation of fan  10  ( FIG. 1 ). 
         [0055]      fig. 11  shows a second embodiment of a fan arrangement  200  having a fan  110  and a mounting part  134 , which latter comprises mounting flanges  134 ′,  134 ″,  134 ′″ for mounting fan arrangement  200 . Fan  110 , like fan  10  of the first embodiment, has a fan housing  30  in which fan wheel  18  is arranged rotatably about rotation axis  23  ( FIGS. 12 ,  13 ), which wheel, with its fan blades  26 ′ to  26 ′, delivers air in the direction of arrow  98  from suction side  12  to discharge side  14  of fan  110  during the operation of fan  10 . Fan housing  30  is suspended in mounting part  34  via membrane  32 . 
         [0056]    Fan  110  has a motor  121  ( FIGS. 12 and 13 ), preferably implemented as an electronically commutated external-rotor motor, to drive its fan wheel  18 . Said motor has a rotor cup  25  ( FIG. 12 ) on which fan wheel  16  is mounted. Mounting flange  38 , which is provided on a motor retaining tray  185  and is joined via struts  129 ′ to  129 ′″ to fan housing  30 , serves for installation of motor  121  in fan housing  30 . Motor retaining tray  185  differs from motor retaining tray  85  of the first embodiment in a manner described below with reference to  FIG. 12 . 
         [0057]    Associated with motor  121  is first circuit board  52 , which is arranged inside fan housing  30 . First circuit board  52  is connected in an electrically conductive manner, via a connector lead  148  ( FIGS. 12 and 13 ), to a second circuit board  154  ( FIGS. 12 and 13 ) that in this case is likewise arranged inside fan housing  30 , as described below with reference to  FIGS. 12 and 13 . 
         [0058]    For delivery of an operating voltage for motor  121 , in  FIG. 11  first circuit board  52  is connected in electrically conductive fashion, e.g. by soldering, via a flexible voltage supply lead  190  that comprises two leads  191 ,  192 ; further leads can be provided, e.g. for a tacho signal or an alarm signal. A strain relief apparatus  170  is provided for lead  190  on mounting part  134 . This apparatus corresponds substantially to strain relief apparatus  70  of the first embodiment, except that hooking posts  73 ′,  73 ″ have been omitted. 
         [0059]      FIG. 12  is a sectioned view of fan arrangement  200  of  FIG. 11 , illustrating membrane  32  joined to fan housing  30  and to mounting part  134 . 
         [0060]    As is evident from  FIG. 12 , motor  121  corresponds substantially to drive motor  21 , described above with reference to  FIG. 7 , having stator arrangement  83  and rotor  88 . As compared with motor retaining tray  85  of the first embodiment, however, motor retaining tray  185  has a greater height and therefore a larger internal space, in which a second circuit board  154  is arranged. The latter is supported, in  FIG. 12 , on a bearing tube  149  of motor retaining tray  185 . Second circuit board  154  is connected in an electrically conductive manner, via a connector lead  148 , to first circuit board  52 . Connector  148  is preferably a contact pin. 
         [0061]      FIG. 13  is a greatly enlarged view of drive motor  121  of  FIG. 12 , illustrating the electrically conductive connection between first and second circuit boards  52  and  154  via contact pin  148 . 
         [0062]    Numerous variants and modifications are of course possible, within the scope of the present invention.