Abstract:
An air-conditioning unit for air-conditioning an air flow may include a multipart housing including a first housing part and a second housing part arranged on top of the first housing part. The housing may further include an air-conditioning segment and a blower segment defining an axis of rotation. The blower segment may have a blower for driving the air flow. A suction chamber and a pressure chamber may be disposed in the blower segment, and the suction chamber and the pressure chamber may be open with respect to one another via a connecting opening. The blower may have an impeller arranged in the connecting opening. The impeller may include a suction side facing towards the suction chamber and a pressure side facing towards the pressure chamber. The housing may further include a connecting duct for fluidically connecting the blower segment to the air-conditioning segment.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to German Patent Application No. 10 2014 221 955.8, filed Oct. 28, 2014, the contents of which are hereby incorporated by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to an air-conditioning unit for air conditioning an air flow, preferably in a motor vehicle. 
       BACKGROUND 
       [0003]    An air-conditioning unit of the type in question is known from EP 2 236 327 A1, for example. It comprises a multipart housing, which has an air-conditioning segment and a blower segment. A blower for driving the air flow is arranged in the blower segment. For this purpose, the blower has an impeller and an electric motor for driving the impeller. During the operation of the blower, the impeller rotates about an axis of rotation. The blower can expediently be configured as a radial blower, and therefore the associated impeller is then configured as a radial impeller. The components of the air-conditioning unit which are required to air-condition the air flow, e.g. at least one air filter, an evaporator of a refrigeration circuit and at least one heating device, are then accommodated in the air-conditioning segment of the housing. The heating device can be configured as an electric heating device, e.g. as a PTC element, where PTC stands for positive temperature coefficient. A heating device of this kind can furthermore be configured as a heat exchanger, through which, on the one hand, the air flow to be air-conditioned and, on the other hand, a heat transfer medium of a heating circuit can flow. 
         [0004]    Water can arise in air-conditioning units of this kind and must be discharged from the housing in order to avoid odours. It is primarily condensation at the evaporator of water carried along in vapour form in the flow which can occur here. In this case, the condensate can be discharged from the housing in a suitable manner. Moreover, there is also the possibility, especially in the case of vehicle applications, that the fresh air drawn in by the blower will already be carrying liquid water in droplet form. In this case, this water can be deposited in the housing on the suction side of the blower and on the pressure side of the blower. 
         [0005]    The abovementioned EP 2 236 327 A1 discloses that water which is deposited in the housing can be discharged by means of a suction-side drainage path and by means of a pressure-side drainage path, wherein the two drainage paths are routed within the housing to a condensed water drain, through which condensed water and deposited water can be discharged from the housing. 
         [0006]    Other air-conditioning units, the housing of which is equipped with at least one drainage path, are known from DE 10 2009 009 065 A1 and from EP 2 00 0 338 A1. 
         [0007]    To improve the performance of the blower and/or to reduce the noise generated by the blower, EP 2 388 159 A2 and EP 2 292 935 A2, for example, disclose the formation on the housing of a blower tongue, which forms a wall segment for radially delimiting a pressure chamber in which the pressure side of the blower is situated. Here, the blower tongue is arranged at a transition from said pressure chamber to a duct leading away therefrom. It has been found that the geometry of this blower tongue has a decisive effect on the efficiency of the blower and on the noise generated by the blower. 
       SUMMARY 
       [0008]    The present invention is concerned with the problem of indicating, for an air-conditioning unit of the abovementioned type, an improved embodiment which is distinguished, on the one hand, by an efficient blower and, on the other hand, by efficient drainage, while suitability for relatively simple manufacture is furthermore desired. 
         [0009]    This problem is solved by the subject matter of the independent claim. Advantageous embodiments form the subject matter of the dependent claims. 
         [0010]    The invention is based on the general concept of arranging, in the blower segment of the housing, on the pressure side of the blower or impeller, a blower tongue which forms a circumferential segment of a radial boundary wall of a pressure chamber in which the pressure side of the impeller is situated. Here, the wall segment forming the blower tongue is arranged at a transition from said pressure chamber to a connecting duct which connects the housing segment fluidically to an air-conditioning segment of the housing in order to carry the air flow from the pressure chamber to the air-conditioning segment during the operation of the air-conditioning unit. Moreover, a suction-side drainage path is provided, which begins in a cavity of the blower tongue and opens into a pressure-side drainage path. To enable the housing having the blower tongue to be produced in a relatively simple manner, it has a plurality of housing parts. In this case, a lower segment of the blower tongue is formed on a first housing part, said segment being hollow and having a closed upper side. An upper segment of the blower tongue is formed on a second housing part, which is placed on top of the first housing part, said upper segment being hollow and having an upper side open towards the suction chamber. The multipart housing is thus in two parts in the region of the blower tongue, thereby making it possible in principle to produce any desired geometry for the blower tongue, while its production remains relatively inexpensive. This is because the housing parts can be produced as injection mouldings or die castings or even as deep-drawn parts, wherein the hollow segments of the blower tongue are advantageous. 
         [0011]    The relative indications “top” and “bottom” relate to a correct installation state of the air-conditioning unit. 
         [0012]    Since the upper segment of the blower tongue has an upper side open towards the suction chamber, it is possible in principle that water which arises in the suction chamber will enter a cavity of the upper segment of the blower tongue. The suction-side drainage path is now connected to this cavity, allowing water which may enter the cavity to be discharged via the suction-side drainage path. 
         [0013]    In this case, the blower is arranged in the blower segment in such a way that the impeller thereof is situated in a connecting opening which connects the pressure chamber to a suction chamber. In this way, the impeller can draw in air from the suction chamber and force or deliver it into the pressure chamber during the operation of the blower. 
         [0014]    The construction of the housing in accordance with the invention enables the blower tongue to be implemented relatively inexpensively. At the same time, it is possible with the aid of the blower tongue to optimize the blower as regards efficiency and noise generation. Moreover, unwanted water accumulation within the blower tongue can be prevented by means of the suction-side drainage path, which is passed through the blower tongue. 
         [0015]    According to an advantageous embodiment, the suction-side drainage path can pass through an interspace, which is formed between the closed upper side of the lower segment of the blower tongue and a lower side of the second housing part. Thus, the first housing part and the second housing part are deliberately matched to one another in such a way that said interspace, through which the suction-side drainage path can be routed, is formed. It is thus possible to dispense with additional measures for the implementation of drainage. 
         [0016]    In another embodiment, a lower side of the upper segment of the blower tongue, said lower side facing the closed upper side of the lower segment of the blower tongue, can have at least one drainage opening, through which the suction-side drainage path passes. The upper section of the blower tongue is thus open and permeable to water on its lower side, making it easier to drain off water which arises in the cavity of the upper segment. 
         [0017]    In another embodiment, the suction-side drainage path can pass between a wall surface of the first housing part which faces away from the pressure chamber and a wall surface of the first housing part which faces the pressure chamber and/or a wall surface of the second housing part which faces the pressure chamber. Here too, deliberate matching is performed in the shaping of the first housing part and/or the second housing part in order to integrate the drainage function without additional components. 
         [0018]    In another embodiment, the first housing part can have, on its lower side, at least one through opening, which is arranged outside the pressure chamber and through which the suction-side drainage path passes. With the aid of this through opening, the drainage path can carry the water which arises in the blower tongue out of the subassembly formed by the first housing part and the second housing part. 
         [0019]    In another embodiment, the suction-side drainage path can be routed to the pressure-side drainage path within the air-conditioning segment. In particular, it is possible here to select a point which is at a relatively low pressure level for bringing together the suction-side drainage path with the pressure-side drainage path, thus reducing the risk of the drained water flowing back from the pressure side to the suction side. 
         [0020]    According to another embodiment, at least one air filter for filtering the air flow can be arranged in the air-conditioning segment, said filter separating a dirty side from a clean side. The suction-side drainage path can now expediently be routed on the clean side to the pressure-side drainage path. On the clean side, there is a relatively low pressure, with the result that the risk of water that has been separated out flowing back through the suction-side drainage path as far as the suction side of the blower is reduced. 
         [0021]    In another embodiment, an evaporator of a refrigeration circuit can be arranged in the air-conditioning segment. In the air-conditioning segment, the housing can then have an evaporator pan, which is arranged underneath the evaporator and in which a water outlet opening is arranged. An embodiment in which the pressure-side drainage path is routed out of the housing through this water outlet opening is then advantageous. In other words, the evaporator pan which serves to collect condensate that can form during the operation of the evaporator is expediently also used to collect the drainage water. The drainage water can thus be discharged from the housing through the same water outlet opening as the condensed water. For example, a condensed water hose connecting the water outlet opening to an environment of the air-conditioning unit can be connected in a conventional manner to the housing. 
         [0022]    According to an advantageous development, the housing can have, in the air-conditioning segment, a filter cover, which is arranged underneath the at least one air filter and has a collecting duct and a water outlet. The suction-side drainage path can now be routed in this collecting duct to the pressure-side drainage path. This can be implemented in a particularly simple manner. 
         [0023]    According to another advantageous embodiment, the pressure-side drainage path can lead from the collecting duct through the water outlet and through a water inlet formed on the evaporator pan as well as through a guide duct formed on the evaporator pan to the water outlet opening. From the collecting duct, the pressure-side drainage path thus carries both drainage water arising on the pressure side and drainage water arising on the suction side, simplifying the drainage or discharge of the drainage water to the evaporator pan. 
         [0024]    In another development, the water outlet of the filter cover can be connected fluidically to the water inlet of the evaporator pan by a water connection, thereby making it possible to bridge a gap between the filter cover and the evaporator pan. For example, the water connection can be configured as a rigid duct or, preferably, as a flexible hose. The use of a flexible hose allows simple adaptation to different embodiments of the air-conditioning unit, which can differ from one another through different relative positions between the water outlet and the water inlet within the housing. 
         [0025]    For its part, the air-conditioning segment of the housing can be subdivided into a filter segment and into a heat transfer segment; while the filter segment contains at least one air filter, an evaporator of a refrigeration circuit and at least one heating device are arranged in the heat transfer segment. Particularly when the air-conditioning segment is subdivided in this way, there is also a local separation between the filter cover, which is situated in the filter segment, and the evaporator pan, which is situated in the heat transfer segment. 
         [0026]    According to another advantageous embodiment, a cover, which covers the open upper side of the upper segment of the blower tongue, can be arranged on the second housing part on an upper side facing the suction chamber. With the aid of this cover, the cavity of the upper segment of the blower tongue can be closed and sealed off to a certain extent, ensuring that only a relatively small amount of water can enter the cavity. In the case of large quantities of water, however, water can enter the cavity past the cover but can be readily discharged via the suction-side drainage path. It is noteworthy here that the open upper side of the upper segment of the blower tongue is formed by an opening in the second housing part. Although this opening is closed to a certain extent by the cover, the opening itself remains present in the second housing part, with the result that the upper segment of the blower tongue has an open upper side, as before. 
         [0027]    In a particularly compact embodiment, the housing can have, in the blower segment, a fresh air inlet open towards the suction chamber. This means that water-containing air can pass directly into the suction chamber, i.e. to the suction side of the blower, through the fresh air inlet during the operation of the air-conditioning unit. Thus, the risk that a relatively large amount of water will arise in the suction chamber is relatively great. However, it is a simple matter to discharge the water that arises on the suction side via the proposed suction-side drainage path. 
         [0028]    The first housing part is advantageously configured as a deep-drawn part or as an injection-moulded part. In addition or as an alternative, the second housing part can be designed as a deep-drawn part or as an injection-moulded part. In particular, deep-drawn parts or injection-moulded parts of this kind made of plastic can be produced inexpensively. Here, the configuration of the upper segment of the blower tongue and of the lower segment of the blower tongue as hollow bodies simplifies the deep drawing or injection moulding of the housing parts. 
         [0029]    According to another advantageous embodiment, the impeller can be arranged horizontally in the housing, with the result that its axis of rotation extends substantially vertically. In the case of a horizontal impeller or an upright axis of rotation, the suction chamber in the blower segment is arranged at the top, while the pressure chamber in the housing segment is arranged at the bottom. The relative indications “horizontal(ly)”, “upright” and “vertical(ly)” each refer to the correct installation state of the air-conditioning unit. The blower is preferably a radial blower, the impeller of which is configured as a radial impeller. 
         [0030]    Further important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated description of the figures with reference to the drawings. 
         [0031]    It is self-evident that the features mentioned above and those which will be explained below can be used not only in the respectively indicated combination but also in other combinations or in isolation without exceeding the scope of the present invention. 
         [0032]    Preferred embodiments of the invention are illustrated in the drawings and are explained in greater detail in the following description, wherein identical reference signs refer to identical or similar or functionally identical components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    Of the figures, each of which is schematic: 
           [0034]      FIG. 1  shows an isometric view of an air-conditioning unit without the blower, 
           [0035]      FIG. 2  shows a highly simplified sectional view of the air conditioning unit in the region of an impeller of the blower transversely to an axis of rotation of the impeller, 
           [0036]      FIG. 3  shows an isometric sectional view of a housing of the air-conditioning unit in the region of a blower tongue, 
           [0037]      FIG. 4  shows an isometric sectional view of the housing in the region of a filter cover, 
           [0038]      FIG. 5  shows an isometric sectional view of the housing in the region of the filter cover and in the region of an evaporator pan. 
       
    
    
     DETAILED DESCRIPTION 
       [0039]    According to  FIG. 1 , an air-conditioning unit  1 , which is used to air-condition an air flow and is preferably used in a motor vehicle, comprises a multipart housing  2 , which has an air-conditioning segment  3  and a blower segment  4 , which are each indicated by braces in  FIG. 1 . At least one filter element  5 , an evaporator (not shown specifically in  FIG. 1 ) of a refrigeration circuit and at least one heating device (likewise not shown specifically here) can be arranged in the air-conditioning segment  2 . The air-conditioning segment  3  can furthermore be subdivided into a filter segment  6  and a heat transfer segment  7  (indicated in  FIG. 5 ), in which case the respective air filter  5  is arranged in the filter segment  6 , while the evaporator, as a cooling device, and the respective heating device are arranged in the heat transfer segment  7 . An evaporator  8  of this kind and a heating device  9 , which are arranged in the heat transfer segment  7  and in the air-conditioning segment  3 , respectively, are furthermore indicated in a purely symbolic way in  FIG. 5 . 
         [0040]    Arranged in the blower segment  4 , on the other hand, is a blower  10 , which is indicated in a highly simplified form only in  FIG. 2  and is used to drive the air flow, which is indicated by an arrow in  FIG. 2  and is denoted by  59 . To drive the air flow  59 , the blower  10  has an impeller  11 , which rotates about an axis of rotation  12  during the operation of the blower  10 . The blower  10  is preferably a radial blower. Accordingly, the impeller  11  is configured as a radial impeller  11 . The blower  10  is furthermore expediently arranged in the blower segment  4  in such a way that the axis of rotation  12  extends substantially vertically, i.e. extends largely from the top down. As a result, the impeller  11  is arranged horizontally in the blower segment  4 . 
         [0041]    In the blower segment  4 , the housing  2  has a suction chamber  13  situated at the top and a pressure chamber  14  situated at the bottom. Formed in the housing  2  is a connecting opening  15 , via which the suction chamber  13  merges into the pressure chamber  14 . The suction chamber  13  and the pressure chamber  14  are thus open with respect to one another via the connecting opening  15 . The impeller  11  of the blower  10  is inserted into said connecting opening  15  in such a way that a suction side  16  of the impeller  11  is exposed to the suction chamber  13 , while a pressure side  17  of the impeller  11  is exposed to the pressure chamber  14 . 
         [0042]    Accordingly, the sectional view shown in  FIG. 2  shows a section through the housing  2  in the blower segment  4  in a section plane which extends perpendicularly to the axis of rotation  12  and which lies below the connecting opening  15 , allowing the pressure chamber  14  and the pressure side  17  of the impeller  11  to be seen in  FIG. 2 . The housing  2  furthermore has a connecting duct  18 , which is shown in part in  FIG. 2 . The connecting duct  18  carries the air flow  59  from the blower segment  4  to the air-conditioning segment  3  or filter segment  6 . For this purpose, the connecting duct  18  opens onto the pressure chamber  14  on the inlet side. A blower tongue  19  is furthermore formed in the blower segment  4 . This is situated at a transition  20  from the pressure chamber  14  to the connecting duct  18 . Here, the blower tongue  19  forms a wall segment  21  for radially delimiting the pressure chamber  14 . In this case, the term “radially” refers to the axis of rotation  12 . According to  FIG. 2 , it is expedient if the impeller  11  is arranged eccentrically in the pressure chamber  14 , in such a way that the pressure chamber  14  is of volute configuration to the outside of the impeller  11 , wherein the cross section of the pressure chamber  14  radially between the impeller  11  and a wall  22  radially enclosing the impeller  11  increases in the direction of rotation  23  of the impeller  11 . In this case, the wall segment  21  of the wall  22  which forms the blower tongue  19  is arranged in the region of the smallest cross section, and the impeller  11  thus rotates in the direction of the blower tongue  19  at its outer circumference. 
         [0043]    According to  FIG. 3 , the housing  2  has a first housing part  24 , on which a lower segment  25  of the blower tongue  19  is formed. The lower segment  25  of the blower tongue  19  is hollow, i.e. is configured as a hollow body, and has an upper side  26  of closed design. The housing  2  furthermore has a second housing part  27 , on which an upper segment  28  of the blower tongue  19  is formed. For this purpose, the second housing part  27  is placed on top of the first housing part  24 , wherein, in particular, at least one tongue and groove joint  29  can be provided in order to fix the upper, second housing part  27  on the lower, first housing part  24 . The upper segment  28  of the blower tongue  19  is also hollow, i.e. configured as a hollow body, and therefore it contains a cavity  32 , wherein it furthermore has an upper side  30  open towards the suction chamber  13 . 
         [0044]    Also formed in the housing  2  is a suction-side drainage path  31 , which leads from the cavity  32  of the upper segment  28  of the blower tongue  19  to a pressure-side drainage path  33 , visible in  FIGS. 4 and 5 , which ultimately leads out of the housing  2 . The suction-side drainage path  31  thus begins in the cavity  32 , which is exposed to the suction chamber  13  and thus to the suction side  16  of the blower  10  via the open upper side  30  of the upper segment  28  of the blower tongue  19 . In contrast, the pressure-side drainage path  33  begins on the pressure side  17  of the blower  10 . 
         [0045]    As can be seen from  FIG. 3 , the suction-side drainage path  31  is passed through an interspace  34 , which is formed between the closed upper side  26  of the lower segment  25  of the blower tongue  19  and a lower side  35  of the second housing part  27 . It can furthermore be seen from  FIG. 3  that at least one drainage opening  37 , through which the suction-side drainage path  31  passes, is provided on a lower side  36  of the upper segment  28  of the blower tongue  19 . Here, said lower side  36  faces the closed upper side  26  of the lower segment  25  of the blower tongue  19 . The suction-side drainage path  31  thus connects the cavity  32  of the upper segment  28  of the blower tongue  19  to the abovementioned interspace  34  via said drainage opening  37 . 
         [0046]    Moreover, the suction-side drainage path  31  leads between a wall surface  38  of the first housing part  24  which faces away from the pressure chamber  14  and a wall surface  39 ,  40  facing the pressure chamber  14 . Here, one wall surface  39  is once again formed on the first housing part  24 , while the other wall surface  40  is formed on the second housing part  27 . It is noteworthy here that the suction-side drainage path  31  is passed through an aperture  60 , which is formed in one of the abovementioned tongue and groove guides  29  by means of which the upper or second housing part  27  is fixed on the lower or first housing part  24 . In the simplest case, the tongue, formed on the upper side  26  of the lower segment  25  of the blower tongue  19 , of this tongue and groove joint  29  has a gap which forms said aperture  36  within the tongue and groove joint  29 . 
         [0047]    At least one through opening  42  is furthermore provided in a lower side  41  of the first housing part  24 , said lower side being remote from the second housing part  27 . Here, the through opening  42  is situated outside the pressure chamber  14 . The suction-side drainage path  31  leads through this through opening  42 . Here, the through opening  42  connects another interspace  43 , which is delimited by the abovementioned wall segments  38 ,  39 ,  40 , to a space  44  which is formed between the lower side  41  of the first housing part  24  and a filter cover  45 , which already forms part of the air-conditioning segment  3  or filter segment  6 . 
         [0048]    In  FIGS. 4 and 5 , two air filters  5  and the installation positions thereof are indicated, said filters separating a dirty side  46  from a clean side  47  in the air-conditioning segment  3  or filter segment  6 . It is expedient if the suction-side drainage path  31  shown in  FIG. 5  is brought together with the pressure-side drainage path  33  on the clean side  47 . Moreover, the suction-side drainage path  31  is brought together with the pressure-side drainage path  33  in the air-conditioning segment  3  or filter segment  6 . 
         [0049]    According to  FIG. 5 , the housing  2  has an evaporator pan  48  in the air-conditioning segment  3  or heat transfer segment  7 , said pan being arranged underneath the abovementioned evaporator  8  and having a water outlet opening  49 . A condensate drain hose (not shown here) can be connected to the water outlet opening  49  on an outer side of the housing  2 . The pressure-side drainage path  33  is passed out of the housing  2  through this water outlet opening  49 . In detail, the filter cover  45  has a collecting duct  50  and a water outlet  51 . As can be seen, the suction-side drainage path  31  is routed in this collecting duct  50  to the pressure-side drainage path  33 . Accordingly, the collecting duct  50  is arranged on the clean side  47 . The pressure-side drainage path  33 , which, from the collecting duct  50  onwards, contains the suction-side drainage path  31 , leads from the water outlet  51  of the filter cover  45  to a water inlet  52  formed on the evaporator pan  48 . Furthermore, the pressure-side drainage path  33  leads through a guide duct  53 , which is likewise formed on the evaporator pan  48 . The guide duct  53  connects the water inlet  52  to the water outlet opening  49 . A water connection  54  connects the water outlet  51  to the water inlet  52 . Here, the water connection  54  is preferably configured as a flexible hose. Configuration of the water connection  54  as a rigid duct is also conceivable in principle. 
         [0050]    According to  FIGS. 1 and 3 , a cover  56  can be arranged on the second housing part  27  on an upper side  55  facing the suction chamber  13 . Here, the cover  56  covers the open upper side  30  of the upper segment  28  of the blower tongue  19 , thereby giving a certain protection to the cavity  32  from water which can arise in the suction chamber  13 . However, this cover  56  is not watertight, and therefore water can enter the cavity  32  past the cover  56 . This water can be discharged from the cavity  32  via the suction-side drainage path  31 . 
         [0051]    According to  FIG. 1 , the housing  2  has, in the blower segment  4 , a fresh air inlet  57  which is open towards the suction chamber  13  and through which fresh air  58  can enter the suction chamber  13  as indicated by an arrow. 
         [0052]    The first housing part  24  and the second housing part  27  are preferably produced as deep-drawn parts or as injection mouldings made of plastic. 
         [0053]    If the impeller  11  is arranged horizontally in the housing  2 , as here, the upright or vertical axis of rotation  12  is obtained. Consequently, the suction chamber  13  is arranged at the top, while the pressure chamber  14  is arranged at the bottom, below the suction chamber  13 .