Patent Publication Number: US-11662160-B2

Title: Collector tube for a heat exchanger

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to German Patent Application No. DE 10 2018 220 143.9, filed on Nov. 23, 2018, the contents of which are hereby incorporated by reference in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to a heat exchanger for a vehicle as well as to a collector tube for such a heat exchanger. 
     BACKGROUND 
     In vehicles, heat exchangers and in particular condensers are used, for example, as part of an air conditioning circuit for regulating the room temperature in the vehicle interior. The heat exchanger or condenser, respectively, has a plurality of flat tubes, which are spaced apart from one another and which are fluidically connected to one another by means of at least one collector tube. A gaseous refrigerant, which was compressed by a compressor of the air conditioning circuit, initially flows into the collector tube through an inlet and subsequently through the flat tubes. While the refrigerant flows through the flat tubes, it dissipates its heat energy to the flat tubes or to the surrounding area of the flat tubes, respectively, so that it cools down and condenses. The condensed or liquid refrigerant, respectively, is supplied to the air conditioning circuit again via an outlet. 
     To specify a flow path of the refrigerant inside the heat exchanger or of the condenser, respectively, at least one separating element is arranged inside the collector tube, so that the collector tube is divided into at least two fluidically separate subareas. In the known prior art, the fixation of such a separating element inside the tube prior to a soldering process is problematic, because a tilting and/or displacing of the separating element can lead to a lack of tightness and/or to an unwanted flow path, so that the desired heat transfer cannot take place in an optimal manner. 
     SUMMARY 
     The present invention is based on the object of specifying a collector tube of the above-mentioned type, in which at least one separating element can be positioned so as to be protected against tilting and/or displacing. 
     The present invention is based on the general idea that the collector tube has at least one recess, through which a separating element can be inserted into the collector tube. 
     The collector tube according to the invention for a heat exchanger, which has at least one flat tube, comprises a recess, through which a separating element is inserted into the collector tube in an insertion position. The insertion position can be characterized in that a boundary contour of the separating element abuts against an inner wall of the collector tube in such a way that a first subarea of the collector tube and a second subarea of the collector tube are fluidically separated from one another by means of the separating element. Tolerances in the inner wall of the collector tube thus have no impact on the tightness of the separating wall, because the separating wall can, for example, be inserted deeply or less deeply into the collector tube, according to the available inner wall, in order to balance the production tolerances of the inner wall. The recess of the collector tube can have an essentially rectangular embodiment. 
     The separating element has a separating wall comprising a separating wall thickness, wherein a clearance fit is present between the separating wall and the recess in response to the insertion of the separating element. A clearance fit can be present, when the separating wall inside the recess has a certain freedom of movement, so that the separating wall can be moved freely against the recess. This can also be understood such that the subarea of the separating element, which embodies the separating wall, can be inserted into the collector tube, without the separating wall touching an edge area of the recess. 
     The separating wall further provides at least one elevation, in order to attain an increase of the separating wall thickness in a subarea of the separating element. Such an elevation can be embodied, for example, integrally by the separating wall and/or by the separating element, wherein it is also conceivable that the elevation can be attached to the separating wall and/or the separating element via a releasable connection or a non-releasable connection. 
     It is provided that, in the insertion position of the separating element, the at least one elevation is arranged in the area of the recess, wherein, in the insertion position of the separating element, a press fit is present between the elevation and the recess. A press fit can be present, when the separating element at least partially experiences an elastic and/or plastic deformation in response to the insertion into the insertion position in the area of the elevation, so that the separating element cannot move freely with respect to the recess. It is thus prevented that the separating element falls out prior to and/or during a soldering process. 
     The separating element is used to segment the collector tube and, for example, to provide for a meander-shaped flow guidance of the refrigerant through the flat tubes. The shape of the separating wall is selected in such a way that a fluid-tight separation of two segments or subareas, respectively, of the collector tube is ensured. The collector tube can thereby be embodied in one piece or also in several pieces. The collector tube can embody a longitudinal duct comprising a cross section, which can be embodied, for example, so as to be essentially circular in some areas and/or essentially semi-circular in some areas. 
     In the case of an advantageous further development of the solution according to the invention, it is provided that the separating element has a ledge, which, in the insertion position of the separating element, is arranged outside of a longitudinal duct of the collector tube. This leads to an improved separation of the separating elements as loose material, wherein a mutual flat attachment is avoided. This can provide for a supply of the separating elements, in response to which separating elements, for example, are guided to the assembly location by a vibrating conveyor via a sliding rail. It can be provided that the ledge thereby hooks into a sliding rail. 
     In the case of a further advantageous embodiment of the solution according to the invention, it is provided that the separating element has at least two elevations, which are spaced apart from one another. It can be provided thereby that a first elevation is arranged on a first surface side of the separating element and a second elevation on a second surface side of the separating element. It is also conceivable, however, that a first elevation and a second elevation are arranged on one surface side of the separating element. The distance between the elevations can, for example, correspond to at least twice the dimension and/or diameter of the respective elevation. A first elevation and a second elevation can be embodied identically or can also be embodied differently. 
     In the case of an advantageous further development of the solution according to the invention, it is provided that at least one elevation has a circular embodiment. The elevation can be embodied, for example, cylindrically and/or in the shape of a truncated cone. 
     In the case of a further advantageous embodiment of the solution according to the invention, it is provided that the separating element at least partially has a curved boundary edge. This curved boundary edge can be embodied essentially complementary to the embodiment of the inner wall of the collector tube, in order to provide for an essentially positive insertion of the separating element. 
     In the case of an advantageous further development of the solution according to the invention, it is provided that the separating is embodied so as to be at least partially complementary to a subarea of an inner wall of the collector tube, in order to provide for an essentially positive insertion of the separating element. 
     In the case of a further advantageous embodiment of the solution according to the invention, it is provided that the collector tube is embodied of a base and a cover. The collector tube can be embodied in at least two parts, wherein the first component is the base and the second component is the cover. The base and the cover are arranged so as to be located opposite one another and can embody a longitudinal duct. 
     The base can have an outer base surface and an inner base surface. The outer base surface is defined as the surface of the base, which is in contact with the external environment in the case of the assembled collector tube. The remaining surface of the base, which is not in contact with the external environment in the case of the assembled collector tube, is defined as inner base surface. 
     The cover can have an outer cover surface and an inner cover surface. The outer cover surface is defined as the surface of the cover, which is in contact with the external environment in the case of the assembled collector tube. The remaining surface of the cover, which is not in contact with the external environment in the case of the assembled collector tube, is defined as inner cover surface. 
     The base and the cover can be assembled in such a way that the longitudinal duct is fluid-tight with respect to the external environment. For this purpose, the base can have at least one base collar. It can be provided that subareas of the inner base surface are in contact with subareas of the inner cover surface. 
     It can be provided that the base is embodied to be essentially flat. In this context, flat can be understood such that in the cross section of the longitudinal duct, the inner base surface has at least one curvature radius, which is larger than the smallest curvature radius of the inner cover surface. 
     In the case of an advantageous further development of the solution according to the invention, it is provided that the cover is arranged so as to be located opposite the base, wherein the base and the cover embody a longitudinal duct, wherein the base has at least one passage comprising an opening for accommodating a flat tube of the heat exchanger. The opening can have a cross section, which is adapted to the flat tube. 
     In the case of a further advantageous embodiment of the solution according to the invention, it is provided that the passage has a collar, which extends away from the longitudinal duct. The collar thus does not protrude into the longitudinal duct thereby. The collar can be torn from the inside to the outside. The respective flat tube can be inserted through the opening and the collar of the passage, wherein the front edge can be flush with the base area. The available space inside the heat exchanger or condenser, respectively, which has to be filled by the refrigerant, can be significantly reduced thereby. When using a comparatively expensive refrigerant, such as, for example, R1234yf, a reduction of the production or operating costs, respectively, of the heat exchanger can also be attained. 
     In the case of a further advantageous embodiment of the solution according to the invention, it is provided that at least one elevation along a first direction of extension and along a second direction of extension has identical dimensions and/or diameters. 
     In the case of an advantageous further development of the solution according to the invention, it is provided that at least one elevation along a first direction of extension and along a second direction of extension has different dimensions and/or diameters. It can be provided that the dimensions and/or diameters of the elevation along the second direction of extension are larger than the dimensions and/or diameters along the first direction of extension. The first direction of extension can be essentially parallel to an insertion direction of the separating element. The second direction of extension can be essentially transverse to an insertion direction of the separating element. The insertion direction is defined as the direction, along which the separating element is inserted into the collector tube in an insertion position. 
     In the case of a further advantageous embodiment of the solution according to the invention, it is provided that at least one elevation extends over the entire width of the separating wall along the second direction of extension. 
     In the case of an advantageous further development of the solution according to the invention, it is provided that at least one elevation can be larger in a diameter and can extend up to a curvature of the entire separating wall, and embodies a crown bow. This increases the elasticity when joining the separating wall, and reduces the required joining force of the separating wall, but simultaneously ensures a reliable abutment and tight soldering of the separating wall in the joint gap of the recess. 
     The invention further relates to a heat exchanger, in particular a condenser for a vehicle, which is equipped with a plurality of flat tubes, which are spaced apart from one another. The flat tubes are thereby fluidically connected to one another by means of at least one collector tube according to the invention, which is described above. For example two collector tubes or also only one collector tube can be provided, wherein in the case of one collector tube, the flat tubes can have a U-shaped course. It can also be provided that a collector tube has an inlet and an outlet, which can be connected to an air conditioning circuit of a vehicle. The flat tubes are introduced into openings of the collector tube, whereby it can be provided that front edges of the flat tubes are essentially flush with the base. If the base provides for a curvature, the front edges of the flat tubes can also have a curved course, so as to attain a flush closure with the base and so as to thus not reduce the flow cross section of the longitudinal duct. 
     Further important features and advantages of the invention follow from the subclaims, from the drawings, and from the corresponding figure description on the basis of the drawings. 
     It goes without saying that the above-mentioned features and the features, which will be described below, cannot only be used in the respective specified combination, but also in other combinations or alone, without leaving the scope of the present invention. 
     Preferred exemplary embodiments of the invention are illustrated in the drawings and will be described in more detail in the below description, whereby identical reference numerals refer to identical or similar or functionally identical components. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In each case schematically, 
         FIG.  1    shows a heat exchanger or condenser, respectively, 
         FIG.  2    shows a perspective view of a collector tube according to the invention prior to the assembly, 
         FIG.  3    shows a perspective longitudinal section of an assembled collector tube, 
         FIG.  4    shows a perspective view of a separating element, 
         FIG.  5    shows a side view of the separating element of  FIG.  4   , 
         FIG.  6    shows a section through a separating element. 
     
    
    
     DETAILED DESCRIPTION 
     As illustrated in  FIG.  1   , the heat exchanger  2  has a plurality of flat tubes  3 , which are fluidically connected to two collector tubes  1 . The collector tubes  1  and the flat tubes  3  are arranged essentially transversely to one another. A first collector tube  1  is provided with an inlet  17 , and a second collector tube  1  has an outlet  18 . The inlet  17  and the outlet  18  can be connected to a non-illustrated air conditioning circuit of a vehicle, wherein the air conditioning circuit can be used to regulate the room temperature in the vehicle interior. 
     If the heat exchanger  2  is used as condenser, a refrigerant of the air conditioning circuit enters in the vaporous aggregate state into the collector tube  1  through the inlet  17  and flows through the flat tubes  3 . Separating elements  5  are inserted in the collector tubes  1  in such a way that for example a meander-shaped flow guidance or flow path, respectively, of the refrigerant results. While the refrigerant flows through the flat tubes  3 , it dissipates its heat energy to the flat tubes  3  or to the surrounding area of the flat tubes  3 , respectively, so that it cools down and condenses. Fins  19 , which increase the mechanical resistance of the heat exchanger  2  and which enlarge the surface, via which the heat energy of the refrigerant can be discharged to the external environment, are arranged between the flat tubes  3 . The condensed refrigerant is supplied to the air conditioning circuit via the outlet  18 . 
       FIG.  2    shows a perspective view of a collector tube  1  according to the invention prior to the assembly.  FIG.  3    shows a perspective longitudinal section of an assembled collector tube  1 . 
     The collector tube  1  consists of a base  12  and a cover  13 , wherein the base  12  has a base collar  23 . Compared to the cover  13 , the base  12  is embodied to be essentially flat. The base  12  and the cover  13  can be made of a sheet metal, wherein the collector tubes  1  as well as the entire heat exchanger  2  can be produced by means of soldering. 
     The base  12  and the cover  13  limit a longitudinal duct  9 , through which a refrigerant can flow. In the assembled state of the collector tube  1 , a subarea of the separating element  5  abuts against an inner wall  11  of the collector tube  1 , in particular against an inner wall  11  of the cover  13 . 
     The base  12  has a plurality of passages  14 , which are arranged spaced apart from one another along the longitudinal extension of the longitudinal duct  9 . Each passage  14  has an opening  15  and a collar  16 , which extends away from the longitudinal duct  9 . The opening  15  has a wide edge and a narrow edge, which correspond to the dimensions of the flat tubes  3  in such a way that the flat tubes  3  can be inserted through the respective opening  15 . The opening  15  of the passage  14  can initially taper towards the longitudinal duct  9  and can subsequently widen again. The insertion of the respective flat tube  3  into the respective passage  14  can be simplified thereby. 
     In areas located opposite a passage  14 , the cover  13  has recesses  22 . These recesses  22  can be punched out of the areas, which are in contact with the base collar  23  after the assembly. These recesses  22  can be embodied to be trapezoidal. 
     The base  4  has recesses  12 , into which the separating elements  13  can be inserted. The separating elements  13  can be inserted prior to or also after the assembly of the base  4  and of the cover  5 . The separating element  13  is used to segment the collector tube  1  or the longitudinal duct  9 , respectively, in order to attain a desired flow direction of the refrigerant through the heat exchanger  2 . 
     An enlarged perspective view of a separating element  5  is shown in  FIG.  4   , wherein a side view of the separating element  5  is illustrated in  FIG.  5   . 
     The separating element  5  has a separating wall  6  comprising a separating wall thickness  20  and at least one elevation  7 . In  FIG.  2   , the separating element  5  is illustrated prior to the insertion into the base  12 , and is shown in an insertion position in  FIG.  3   . 
     The separating wall  6  has a shape, which corresponds to the cross sectional contour of the longitudinal duct  9 , so that the separating element  5 , in its insertion position, provides for a fluid-tight segmenting or separation, respectively, of the collector tube  1  or of the longitudinal duct  9 , respectively. For this purpose, the separating element  5  can have a curved boundary edge  10 , which can be embodied so as to be at least partially complementary to a subarea of the inner wall  11  of the collector tube  1 . 
     The elevation  7  leads to a local increase of the separating wall thickness, so that a separating wall thickness  21 , which is larger than the separating wall thickness  20 , is present in this area. The elevation  7  can be produced by means of additionally applied material or also, for example, by means of a forming process. The dimensions of the recess  4  are selected in such a way that the separating wall  6  can be pushed into the recess  4  without large resistance, wherein the dimensions of the elevation  7  are selected in such a way that, in the insertion position of the separating element  5 , the elevation  7  is pressed into the recess  4 . The separating element  5  has two elevations  7 , which are spaced apart from one another and which have a circular and/or cylindrical and/or truncated cone-shaped embodiment. 
     In the embodiment illustrated here, in particular in  FIG.  4   , the respective elevation  7  has identical dimensions and/or diameters along a first direction of extension  100  and along a second direction of extension  101 . In a non-illustrated exemplary different embodiment, at least one elevation  7  can have different dimensions and/or diameters along a first direction of extension  100  and along a second direction of extension  101 . In a further non-illustrated exemplary embodiment, at least one elevation  7  can extend over the entire width of the separating wall  6  along the second direction of extension  101 . In a further non-illustrated exemplary embodiment, at least one elevation  7  can be larger in a diameter and can extend up to a curvature of the entire separating wall  6  and can embody a crown bow. 
     The separating element  5  can have a ledge  8 , which is arranged outside of the longitudinal duct  9  in the insertion position of the separating element  5 . The ledge  8  can be produced by means of additionally applied material or also for example by means of a forming process. 
     The separating wall thickness  21  and the separating wall thickness  20  can be measured from a common reference point and/or from a common reference line  24 . An observation of the separating wall thickness  21  and of the separating wall thickness  20  can thereby take place in the side view, wherein for example recesses and/or bulges  25 , which are created, for example, by means of a forming process and/or production process, are not included. This is illustrated in an exemplary manner in  FIG.  6   , in which a section through a separating element  5  is shown, so that a possible bulge  25  becomes visible. Even though the elevation  7  is embodied here by means of a local forming of the separating wall  6 , this effectively leads to an increase of the separating wall thickness  20 , so that the elevation  7  is arranged in the area of the recess  4  in the insertion position of the separating element  5 , and so that a press fit forms between the elevation  7  and the recess  4 .