Abstract:
A housing attachment for an electric machine is constructed in compliance with protection class IP 23 and includes a first projected edge disposed at a first border wall such that water located in the middle section at the first border wall drips off no later than at the first projected edge and is led directly or indirectly to the first air inlet opening. Proximate to the first air inlet opening are first laminates which deflect incoming air flowing into the feed air channel to a second edge area. Proximate to the second air outlet opening are second laminates that impart to the flow direction of the outgoing air leaving the outlet air channel a component directed to the top of the electric machine. Third laminates are disposed in an end area of the outlet air channel to deflect the outlet air flowing in the outlet air channel away from the top of the electric machine.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is the U.S. National Stage of International Application No. PCT/EP2009/053336, filed Mar. 23, 2009, which designated the United States and has been published as International Publication No. WO 2009/121734 and which claims the priority of German Patent Application, Serial No. 10 2008 016 889.0, filed Apr. 2, 2008, pursuant to 35 U.S.C. 119(a)-(d). 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a housing attachment for an electrical machine,
         wherein the housing attachment has a lower face,   wherein the lower face has a first and a second edge area by means of which the housing attachment can be placed on an upper face of the electrical machine,   wherein the lower face has a center area which is arranged between the two edge areas and is at a distance from the upper face of the electrical machine,   wherein the housing attachment has an inlet air channel which extends from a first air inlet opening, which is arranged in the center area, to a first air outlet opening, which is arranged in the first edge area and faces the upper face of the electrical machine, such that inlet air can be sucked in from an air inlet of the electrical machine via the inlet air channel,   wherein a separating device is arranged in the inlet air channel between the first air inlet opening and the first air outlet opening, such that the inlet air channel runs in a U-shape or curved to an even greater extent,   wherein the inlet air channel is bounded on its side facing away from the lower face by a first boundary wall which is inclined at least in a center section such that, seen in the flow direction of the inlet air, a distance between the first boundary wall and the first air inlet opening decreases at least as far as the separating device,   wherein the housing attachment has an outlet air channel, which engages over the inlet air channel and extends from a second air inlet opening, which is arranged in the second edge area and faces the upper face of the electrical machine, to a second air outlet opening, such that outlet air can be blown out from an air outlet of the electrical machine via the outlet air channel,   wherein the second air outlet opening is arranged on a high face of the housing attachment, which has a common edge with the first edge area,   wherein the common edge is that edge of the first edge area which is furthest away from the second edge area,   wherein the outlet air channel is bounded on its side facing the lower face by a second boundary wall which is inclined at least in an end area adjacent to the second air outlet opening such that, seen in the flow direction of the outlet air, a distance between the second boundary wall and the first air outlet opening decreases at least in the end area.       

     A housing attachment such as this is commercially known and already operates quite well, but offers only ingress protection class IP 23. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to develop a housing attachment of the type described above further such that it complies with ingress protection class IP 24W, while nevertheless keeping the flow resistance in the inlet air channel and in the outlet air channel as low as possible. 
     The object is achieved by an appliance attachment according to the invention, including in addition to the initially mentioned features of the appliance attachment the following features:
         that the housing attachment has a first drip edge, which is arranged on the first boundary wall such that water which is located on the first boundary wall in the center section drips off at the latest on the first drip edge,   that the water which drips off on the first drip edge is passed directly or indirectly to the first air inlet opening,   that first laminates are arranged in the area of the first air inlet opening and deflect the inlet air flowing into the inlet air channel to the second edge area,   that second laminates are arranged in the area of the second air outlet opening which give a component directed to the upper face of the electrical machine to the flow direction of the outlet air flowing out of the outlet air channel, and   that third laminates are arranged in the end area in the outlet air channel and deflect the outlet air flowing in the outlet air channel away from the upper face of the electrical machine.       

     In one preferred refinement of the housing attachment, the first laminates are bent at least once. This results in them being more robust. In particular, it is possible that the first laminates have a bend at their ends facing the upper face of the electrical machine, on the basis of which those ends of the first laminates which face the upper face of the electrical machine run essentially parallel to the upper face of the electrical machine. Alternatively or additionally, it is possible that the first laminates have a bend at their ends remote from the upper face of the electrical machine, on the basis of which those ends of the first laminates which are remote from the upper face of the electrical machine run essentially orthogonally to the upper face of the electrical machine. 
     The second laminates can likewise be bent at least once. One preferred refinement for this purpose provides that the second laminates have a bend at their ends facing the upper face of the electrical machine, on the basis of which those ends of the second laminates which face the upper face of the electrical machine run essentially orthogonally to the upper face of the electrical machine. Alternatively or additionally, it is possible that the second laminates have a bend at their ends which are remote from the upper face of the electrical machine, on the basis of which those ends of the second laminates which are remote from the upper face of the electrical machine run essentially orthogonally to the upper face of the electrical machine. 
     The third laminates can likewise be bent at least once. One preferred refinement for this purpose provides that the third laminates have a bend at their ends facing the upper face of the electrical machine, on the basis of which those ends of the third laminates which face the upper face of the electrical machine run essentially parallel to the upper face of the electrical machine. Alternatively or additionally, it is possible that the third laminates have a bend at their ends remote from the upper face of the electrical machine, on the basis of which those ends of the third laminates which are remote from the upper face of the electrical machine run essentially parallel to the upper face of the electrical machine. 
     In a further preferred refinement, the first boundary wall is identical to the second boundary wall. This results in the housing attachment having a physically simple design. 
     In one preferred refinement of the present invention, the inlet air channel has a larger cross section in the area of the first air inlet opening than in the area of the first air outlet opening. This measure makes it possible to reduce the flow resistance even further. 
     One particularly preferred refinement of the present invention provides that the housing attachment has a second drip edge which, seen in the flow direction of the outlet air, is arranged in the end area in front of the second laminates on a third boundary wall, which is opposite the second boundary wall, such that water which is located in the end area drips off at the latest on the second drip edge onto the second boundary wall. The second drip edge can in this case be arranged in front of the third laminates, seen in the flow direction of the outlet air. 
     It is possible that the separating device is in the form of a web which projects into the inlet air channel. Alternatively, it is possible that the separating device is in the form of a projection which projects into the inlet air channel. In the last-mentioned case, the projection may, in particular, be in the form of a step. 
     It is possible for the first air inlet opening to be at a distance from the first edge area. Alternatively, the first air inlet opening can extend to the first edge area. 
     In one preferred refinement of the present invention, the separating device has a drain area which is adjacent to the first air inlet opening and is inclined toward the first air inlet opening. In this case, the first drip edge can be arranged such that the water which drips off the first drip edge drips onto the inclined drain area. Alternatively, it is possible that, seen in the flow direction of the inlet air, the first drip edge is arranged in a transitional area from the first air inlet opening to the separating device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Further advantages and details will become evident from the following description of one exemplary embodiment and in conjunction with the drawings, in which, illustrated in outlined form: 
         FIG. 1  shows a section illustration of an electrical machine and of an appliance attachment, 
         FIG. 2  shows a further section illustration of the electrical machine and of the housing attachment shown in  FIG. 1 , and 
         FIG. 3  shows, schematically, the method of operation of laminates in the housing attachment according to the invention, in order to achieve ingress protection class IP 24W. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In  FIGS. 1 and 2 , an electrical machine  1  is arranged horizontally. The term “arranged horizontally” in this case means that a rotor shaft  2  of the electrical machine  1  runs horizontally. The electrical machine  1  has a machine housing  3  which itself has an upper face  4 . An air inlet  6  and an air outlet  7  of the electrical machine  1  are located on the upper face  4 , axially offset with respect to one another—with respect to a rotation axis  5  of the rotor shaft  4 . The electrical machine  1  sucks in inlet air  8  via the air inlet  6 . It passes the inlet air  8  through the electrical machine  1  in order to cool the electrical machine  1 . The air which has passed through the electrical machine  1  is blown out by the electrical machine  1  via the air outlet  7  as outlet air  9 . 
     Solid foreign bodies and water can enter the electrical machine  1  via the air inlet  6  and the air outlet  7 . In order to prevent this (within limits), a housing attachment  10  is provided. The housing attachment  10  is in this case intended to comply with ingress protection class IP 24W. The housing attachment  10  is therefore intended to ensure the following (in accordance with IEC 60034-5):
         It is intended to ensure protection against ingress of solid bodies with a diameter of more than 12 mm.   It is intended to ensure protection against the ingress of water projected by a nozzle and relatively small particles at high speed from all directions,   there should be an area in the induction manifold in which the air speed does not exceed 3 ms.   There should be three 90° direction changes in the induction manifold.       

     In order to comply with these conditions and nevertheless to keep the air resistance as low as possible, the housing attachment  10  as shown in  FIGS. 1 and 2  is designed as follows: 
     The housing attachment  10  has a lower face  11  which itself has a center area  12  and two edge areas  13 ,  14 , which are adjacent to the center area  12  on both sides. The center area  12  is therefore arranged between the edge areas  13 ,  14 . The edge areas  13 ,  14  of the housing attachment  10  are placed on the upper face  4  of the electrical machine  1 . In contrast, the center area  12  is separated from the upper face  4  of the electrical machine  1 . 
     A first air inlet opening  15  is arranged in the center area  12 . The first air inlet opening  15  faces the upper face  4  of the electrical machine  1 , but is at a distance from the upper face  4  of the electrical machine  1 . The first air inlet opening  15  may be at a distance from the second edge area  14 . However, it is likewise possible for it to be adjacent to the second edge area  14 . 
     A first air outlet opening  16  is arranged in the first edge area  13  and likewise faces the upper face  4  of the electrical machine  1 . The first air outlet opening  16  interacts with the air inlet  6  of the electrical machine  1 . 
     The housing attachment  10  has an inlet air channel  17  which extends from the first air inlet opening  15  to the first air outlet opening  16 . This configuration allows the inlet air  8  to be sucked in from the air inlet  6  of the electrical machine  1  via the inlet air channel  17 . 
     A separating device  18  is arranged in the inlet air channel  17  between the first air inlet opening  15  and the first air outlet opening  16 . The inlet air channel  17  therefore runs in a U-shape or is curved to an even greater extent. In this case, the air inlet channel  17  preferably has a larger cross section in the area of the first air inlet opening  15  than in the area of the first air outlet opening  16 . 
     As shown in  FIG. 1 , the separating device  18  is in the form of a projection  18 , which projects into the inlet air channel  17 . In this case, the first air inlet opening  15  is at a distance from the first edge area  13 , since the projection  18  separates the first air inlet opening  15  from the first edge area  13 . The projection  18  may be in the form of a step  18 . However, other refinements of the projection  18  are also possible, for example as a dome-like bulge. 
     As an alternative to the embodiment as a projection  18 , the separating device could also be in the form of a web projecting into the inlet air channel  17 . In this case, the web may alternatively be straight or bent. In particular, it is therefore possible for the separating device to consist, for example, exclusively of a side surface  18   a  of the projection  18  or for the separating device to have the side surface  18   a  and a further side surface  18   b  but not, in contrast, a side surface  18   c  of the projection  18 . When the separating device is in the form of a web, the first air inlet opening  15  can extend as far as the first edge area  13 . 
     The inlet air channel  17  is bounded on a side which is remote from the lower face  11  by a first boundary wall  19 . The first boundary wall  19  is inclined at least in a center section  20 . This results in a distance a 1  between the first boundary wall  19  and the first air inlet opening  15  decreasing at least as far as the separating device  18 . 
     A second air inlet opening  21  is arranged in the second edge area  14 . The second air inlet opening  21  faces the upper face  4  of the electrical machine  1  and interacts with the air outlet  7  of the electrical machine  1 . A second air outlet opening  23  is arranged on a high face  22  of the housing attachment  10 . The high face  22  is defined by having a common edge  24  with the first edge area  13 . The common edge  24  is in this case that edge of the first edge area  13  which is furthest away from the second edge area  14 . 
     The housing attachment  10  has an outlet air channel  25  which extends from the second air inlet opening  21  to the second air outlet opening  23  and thus engages over the inlet air channel  17 . This configuration allows the outlet air  9  to be blown out from the air outlet  7  of the electrical machine  1  via the outlet air channel  25 . 
     On its side facing the lower face  11 , the outlet air channel  25  is bounded by a second boundary wall  26 . The second boundary wall  26  is inclined at least in an end area  27  adjacent to the second air outlet opening  23 . This means that, seen in the flow direction of the outlet air  9 , a distance a 2  between the second boundary wall  26  and the first air outlet opening  16  decreases at least in the end area  27 . 
     The second boundary wall  26  may be a specific boundary wall, which is not the same as the first boundary wall  19 . However, the first boundary wall  19  is preferably identical to the second boundary wall  26 . 
     The housing attachment  10  furthermore has a first drip edge  28 . The first drip edge  28  is arranged on the first boundary wall  19  such that the first drip edge  28  projects from above into the inlet air channel  17 . Seen in the flow direction of the inlet air  8 , the first drip edge  28  may in this case be arranged in a transitional area  29  from the first air inlet opening  15  to the separating device  18 . This arrangement in conjunction with the inclined arrangement of the first boundary wall  19  means that water which is located in the center section  20  on the first boundary wall  19  drips off at the latest on the first drip edge  28 , and is carried directly to the first air inlet opening  15 . 
     Alternatively, it is possible for the side surface  18   b  which is adjacent to the first air inlet opening  15  to be inclined. In this case, the side surface  18   b  is in the form of a drain area  18   b . In this case, the first drip edge  28  can be arranged such that the water which drips off the first drip edge  28  first of all drips onto the inclined drain area  18   b , from where it is carried to the first air inlet opening  15 . In this case, the water which drips off on the first drip edge  28  is carried indirectly to the first air inlet opening  15 . 
     First laminates  30  are arranged in the area of the first air inlet opening  15 . The first laminates  30  deflect the inlet air  8  flowing into the inlet air channel  17  toward the second edge area  14 . In individual cases, it may in this case be sufficient to arrange exclusively the first laminates  30  in the area of the first air inlet opening  15 . In contrast, in general, a mesh grid  31  with a grid width of at most 12 mm is additionally arranged in the area of the first air inlet opening  15 . 
     In one preferred refinement of the present invention, the first laminates  30  are bent at least once. This measure makes it possible to make the first laminates  30  more mechanically robust. At the same time, this makes it possible to reduce the susceptibility of the first laminates  30  to oscillations and vibration during operation. 
     By way of example, the first laminates  30  may have a first bend  33  at their ends  32  facing the upper face  4  of the electrical machine  1 . Because of the first bend  33 , those ends  32  of the first laminates  30  which face the upper face  4  of the electrical machine  1  run essentially parallel to the upper face  4  of the electrical machine  1 . 
     Alternatively or additionally, the first laminates  30  may have a second bend  35  at their ends  34  which are remote from the upper face  4  of the electrical machine  1 . Because of the second bend  35 , those ends  34  of the first laminates  30  which are remote from the upper face  4  of the electrical machine  1  run essentially orthogonally to the upper face  4  of the electrical machine  1 . 
     Furthermore, second laminates  36  are arranged in the area of the second air outlet opening  23 . The second laminates  36  give the flow direction of the outlet air  9 , as it flows out of the outlet air channel  25 , a component which is directed at the upper face  4  of the electrical machine  1 . In individual cases, it may be sufficient in this case to arrange exclusively the second laminates  36  in the area of the second air outlet opening  23 . In general, however, a mesh grid  37  with a grid width of at most 12 mm is additionally arranged in the area of the second air outlet opening  23 . 
     Analogously to the first laminates  30 , the second laminates  36  may also be bent at least once. This achieves the same effects for the second laminates  36  as for the first laminates. 
     By way of example, the second laminates  36  may have a first bend  39  at their ends  38  facing the upper face  4  of the electrical machine  1 . Because of the first bend  39 , those ends  38  of the second laminates  36  which face the upper face  4  of the electrical machine  1  run essentially orthogonally to the upper face of the electrical machine  1 . 
     Alternatively or additionally, the second laminates  36  may have a second bend  41  at their ends  40  which are remote from the upper face  4  of the electrical machine  1 . Because of the second bend  41 , those ends  40  of the second laminates  36  which are remote from the upper face  4  of the electrical machine  1  run essentially orthogonally to the upper face  4  of the electrical machine  1 . 
     Finally, third laminates  42  are arranged in the outlet air channel  25 . The third laminates  42  deflect the outlet air  9  flowing in the outlet air channel  25  away from the upper face  4  of the electrical machine  1 . 
     Analogously to the first and the second laminates  30 ,  36 , the third laminates  42  may also be bent at least once. This results in the same effects for the third laminates  42  as those already mentioned for the first and second laminates  30 ,  36 . 
     By way of example, the third laminates  42  may have a first bend  44  at their ends  43  facing the upper face  4  of the electrical machine  1 . Because of the first bend  44 , those ends  4  of the third laminates  42  which face the upper face  4  of the electrical machine  1  run essentially parallel to the upper face  4  of the electrical machine  1 . 
     Alternatively or additionally, the third laminates  42  may have a second bend  46  at their ends  45  which are remote from the upper face  4  of the electrical machine  1 . Because of the second bend  46 , those ends  45  of the third laminates  42  which are remote from the upper face  4  of the electrical machine  1  run essentially parallel to the upper face  4  of the electrical machine  1 . 
     Because of the first laminates  30 , water  47  projected by a nozzle can enter the inlet air channel  17  only in a very narrow angle range, see  FIG. 3 . The water  47  which enters after being projected by a nozzle in this case either strikes the inclined section of the first boundary wall  19  or an intermediate wall  48  which is adjacent to the first boundary wall  19  toward the second edge area  14 . If the water  47  projected by a nozzle strikes the inclined section of the first boundary wall  19 , it either drips directly onto the first air inlet opening  15  or runs to the first drip edge  28 , from where it drips onto the first air inlet opening  15 . If the water  47  projected by a nozzle strikes the intermediate wall  48 , it runs away directly toward the first air inlet opening  15 . 
     The second laminates  36  analogously mean that water  49  projected by a nozzle can enter the outlet air channel  25  only in a very narrow angle range. The water  49  which has entered having been projected by a nozzle strikes the third laminates  42 . From there, it sprays in the end area  27  onto the second boundary wall  26 , or drips onto the second boundary wall  26  in front of the third laminates  42  and thus likewise in the end area  27 . Because of the inclined arrangement of the second boundary wall  26 , the water  49  projected by a nozzle then runs away out of the outlet air chamber  25 . 
     The housing section  10  may have a second drip edge  50  in order to provide even better protection against the ingress of water. If the second drip edge  50  is present, it is arranged, as seen in the flow direction of the outlet air  9 , in front of the second laminates  36  on a third boundary wall  51 , which is opposite the second boundary wall  26 . This means that water  49  which is located in the end area  27  drips onto the second boundary wall  26  at the latest on the second drip edge  50 . The second drip edge  50  is in this case preferably arranged in front of the third laminates  42 , seen in the flow direction of the outlet air  9 . 
     The housing attachment  10  designed according to the invention makes it possible to comply in a simple manner with ingress protection class IP 24W, while nevertheless keeping the air resistance low. 
     The above description is intended only to explain the present invention. The scope of protection of the present invention is intended, in contrast, to be governed exclusively by the attached claims.