Abstract:
A method for the production of a receiving device for the flow tubes of a heat exchanger with openings for receiving the flow tubes. One opening is at least partially produced by a first forming method and at least partially by a second forming method that is different from the first.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method for the production of a heat exchanger. The method is described in terms of a heat exchanger which is used in motor vehicles, for example in air-conditioning systems of a motor vehicle and the like. The method can however also be applied to other heat exchangers. 
     BACKGROUND OF THE INVENTION 
     Heat exchangers of said type conventionally have a plurality of throughflow tubes, through which a refrigerant is conveyed. Said throughflow tubes open out into tube plates which are conventionally arranged at the ends of the tubes. 
     For this purpose, the tube plates have openings into which or through which the throughflow tubes can be inserted. Several production methods are known from the prior art for producing said openings, which are referred to in the following as rim holes. Said rim holes can for example be generated by punching or else by means of tearing processes such as lancing or the like. 
     While, in the case of punching, the opening is generated by means of a shearing process, in a tearing process, the material to be machined is expanded and torn apart. 
     The advantages of a punching process are that the production is relatively simple, the opening or rim hole produced in such a way has a high degree of accuracy and any cross-sectional shape can be produced. If lancing is used as a production method from the solid sheet metal material, then it is possible in this way to generate funnel-shaped insertion bevels of the rim hole, and thereby to obtain facilitated assembly and soldering processes. In this case, a solder coating is additionally obtained in the contact or connecting region between the throughflow tube and the rim hole when using solder-coated metal starting sheets. 
     Finally, a larger possible contact area between the throughflow tubes and the rim holes or openings is generated than in the case of punched rim holes, since the latter can corresponding at most to the metal sheet thickness of the base or of the collector. 
     SUMMARY OF THE INVENTION 
     The object of the invention is that of utilizing the advantages of both methods in the production. 
     In the method according to the invention for the production of a holding device for throughflow tubes of a heat exchanger having openings for holding the throughflow tubes, at least one opening is generated partially by means of a first shaping process and at least partially by means of a second shaping process which is different from the first shaping process. 
     A shaping process is to be understood to mean any methods are suitable for imparting a predefined shape to a base material such as for example a base metal sheet, such as for example for generating an opening or a rim hole in the base material. 
     A holding device is to be understood to mean a device which holds at least one region of the throughflow tubes, for example their end regions, which are inserted into the openings of the holding device. 
     The first shaping process is preferably a punching process and the second shaping process is preferably a tearing process. 
     Here, as illustrated above, a punching process is to be understood to mean a process in which the opening is generated by means of a shearing process. A tearing process is to be understood to mean a process in which the opening is generated at least at times by means of drawing or tearing. 
     An at least partial generation of the opening by means of the one and the other process is to be understood to mean that certain regions of the opening are generated by means of the one shaping process, such as for example punching, and other regions of the opening are generated by means of the further shaping process, that is to say in particular tearing. 
     A further possibility is to use both shaping processes on predefined regions of the opening which is to be generated. 
     Here, those regions of the openings which have particularly complex cross-sectional shapes, such as for example central regions with a very small width, are generated by means of the punching process, while other regions are generated by means of the tearing process. 
     The first shaping process and the second shaping process preferably take place at substantially the same time. It is possible here for the two processes to be carried out in one working step. 
     It is preferably also possible for the first shaping process and the second shaping process to take place in separate process steps. It is possible here for punching to initially take place, and subsequently for a tearing process to be used; it is however also possible for the tearing process to initially be used and subsequently for a punching process to be carried out. 
     The present invention is also aimed at a method for the production of a heat exchanger, wherein, in one method step during the production, a holding device is carried out according to an above-described method, and the throughflow tubes are subsequently connected at least in sections to the holding device by a connecting means. 
     Here, the connecting means is preferably solder or the like. It is possible here for the connecting means to be applied after the production of the rim hole. It is however preferably also possible for initially solder-coated metal sheets to be used. In this case, solder-coated edges are generated as a result of the above-described process, in particular the tearing process. Said edges or collars are generated, in particular but not exclusively, in the form of insertion bevels, by means of which the assembly and/or soldering processes are facilitated. 
     In addition, as mentioned above, the collar serves to increase the contact area between the rim holes and the throughflow tubes, which likewise facilitates the production, in particular the soldering processes, and provides a higher degree of impermeability of the end products. 
     The invention is also aimed at a holding device for throughflow tubes of a heat exchanger, which holding device has a plurality of openings which are suitable for holding the throughflow tubes, with the openings being arranged substantially in a predefined main plane of the holding device and having a predefined circumference. Here, according to the invention, the openings have, in at least one region, a border which protrudes from the main plane and, in at least one region of the circumference, substantially do not protrude from the main plane. 
     A border is to be understood here, in particular but not exclusively, as a collar which is arranged around the circumference. 
     The main plane is to be understood to mean a geometric plane in which the individual openings are arranged. In one embodiment, the plane can for example be formed by the metal sheet, which is to be machined, itself. It is however also possible for the tube plate to have a base plane which is arranged laterally offset relative to the main plane in which the openings are arranged. 
     Regions which substantially do not protrude from the main plane are to be understood in the following to mean regions without borders or collars. Here, “without borders” or “without collars” does not exclusively mean that no elevations beyond the main plane may be present. 
     In a further preferred embodiment, the borders point from the main plane in substantially the direction of the ends of the throughflow tubes. This means that the throughflow tubes are inserted through the openings, and the borders project from the main plane in the same direction in which the throughflow tubes are inserted through the openings. 
     The borders can however also, as mentioned above, run obliquely with respect to the main plane and form insertion bevels which facilitate the assembly, in particular the connection to the throughflow tubes. 
     In a further preferred embodiment, the borders protrude substantially perpendicularly from the main plane. Here, the borders protrude between 0.3 mm and 3.0 mm, preferably between 0.5 mm and 2.0 mm and particularly preferably between 0.5 mm and 1.0 mm from the plane. Said protrusions are co-determined here by the width of the opening which is to be generated. 
     In a further preferred embodiment, the openings have an elongate shape. “Elongate” is to be understood to mean that the opening has a predefined length and a width which is considerably reduced in relation to said length. The reason for this is that the throughflow tubes are conventionally flat tubes whose ends likewise have an elongate cross section. 
     In a further preferred embodiment, the openings substantially do not protrude from the main plane in their end regions. This means that for example a gap or the like is provided or generated in the end region. 
     In a further preferred embodiment, the openings have a central region with a reduced width. The central regions of the throughflow tubes are inserted through said central region. Said central region are narrowed in their width in order to divide the throughflow tube into two regions in which flow preferably passes in different flow directions in each case. 
     The openings preferably substantially do not protrude from the main plane in the central regions. This means that no borders or collars are provided in the central region. 
     The reason for this is that the central regions have a reduced width, and therefore the production is carried out by means of a more precise method such as, in particular but not exclusively, punching, which generates substantially no borders. 
     In a further preferred embodiment, the main plane is arranged so as to be offset parallel relative to the base plane of the holding device. Here, the main plane is preferably arranged closer than the base plane to the end of the throughflow tubes. This means that the throughflow tubes protrude geometrically through both the base plane and the main plane. 
     The invention is also aimed at a heat-exchanging device having a plurality of throughflow tubes which are suitable for transporting a refrigerant, with a holding device of the above-described type being arranged on at least one end section of the throughflow tubes. It is preferable for in each case one holding device of the above-described type to be arranged on both end sections of the throughflow tubes. Here, the device preferably has a partition which is arranged perpendicularly with respect to the rim holes, thereby providing a division to form two flow regions. 
     In a further preferred embodiment, the separating device, in particular the partition, is aligned substantially parallel to the passage openings. The separating device is preferably arranged in a holding section which has the guide faces for retaining the separating device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages and embodiments of the present invention can be gathered from the appended drawings. 
         FIG. 1  is a perspective illustration of a holding device according to the invention in detail, 
         FIG. 2  is a perspective illustration of the base device according to the invention in a further embodiment, 
         FIG. 3  is a rear view of the further embodiment of the base device according to the invention, 
         FIG. 4  is a further illustration of the base device according to the invention as per  FIG. 2 , 
         FIG. 5  is a rear view of a further embodiment of the base device according to the invention as per  FIG. 2 , 
         FIG. 6  is an exploded illustration of the heat-exchanging device according to the invention, 
         FIG. 7  is an illustration of the device as per  FIG. 6 , 
         FIG. 8  shows a cross section of the base device of  FIG. 6  transversely with respect to the partition along a partition slot, 
         FIG. 9  shows a cross section of the base device of  FIG. 6  transversely with respect to the non-slotted partition, 
         FIG. 10  is a perspective illustration of the base device according to the invention in a further embodiment, 
         FIG. 11  shows a rear view of the further embodiment of the base device according to the invention, 
         FIG. 12  is an exploded illustration of the further embodiment of the heat-exchanging device according to the invention, 
         FIG. 13  is an exploded illustration of the further embodiment of the heat-exchanging device according to the invention in a rear view, 
         FIG. 14  is a perspective illustration of the further embodiment of the heat-exchanging device, and 
         FIG. 15  shows a cross section through the base device of the device as per  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1 , the reference symbol  1  relates to a holding device or a tube plate as per the present invention. Said holding device has two side borders  3   a  and  3   b  which serve for connecting to a further device, for example a cover. For this purpose, the side borders can have obliquely-running sections  4   a  and  4   b  which serve for engagement with a cover. 
     The tube plate has a thickness d which is between 0.2 mm and 3 mm, preferably between 0.5 mm and 2 mm and particularly preferably in the range from 0.5 mm to 1 mm. Provided in the tube plate is a plurality of openings  6 . Said openings have an elongate shape and are situated together in a main plane H. 
     By means of the production method according to the invention, which is composed of a combination of a punching process and a drawing process, in the circumferential region of the openings  6 , borders or collars  8  are generated in one region of the circumference, and not in other regions  7 . 
     The main plane H is illustrated in  FIG. 1  by the two dashed lines. Situated in said plane are the respective openings  6 , more precisely the circumferential borders of the openings  6  in those regions  7  in which there are no collars. Also, in  FIG. 1 , a partition  21  which will be explained further below is aligned substantially perpendicular to the main plane H. 
     The transition between the borders  8  and the regions  7  without borders is illustrated here in the manner of a step. The transition can however also be continuous or, in the mathematical sense, differentiable. The borders  8  themselves can also have rounded-off shapes. 
     The borders  8  are illustrated here with a constant height h, though the height can however also vary in different regions. The height of the borders or collars  8  can also differ from opening  6  to opening  6 . 
     The openings have a central region  6   a  which has a reduced width in relation to the remaining region of the opening. Said narrowed region serves for holding a central region of the throughflow tubes (not shown) which are inserted through the openings  6 . Since relatively high demands must be made of the precise cross-sectional shape in this region, this region is produced by means of punching, that is to say there is no circumferential border or collar  8  in this region. 
     In the end regions  9  of the openings  6 , too, there is a gap  11  which is generated as a result of the lancing process. Said gap  11  is also illustrated by rectilinear profile. The gap  11  can however also have curved borders. 
     In this embodiment, the plane H in which the openings  6  are arranged is laterally offset with respect to a base plane B. The base plane B is to be understood to mean the plane from which the side borders  3   a  and  3   b  extend. Provided from the base plane B toward the openings  6  is a bevel  12 . It is however also possible here for the main plane H and the base plane B to substantially geometrically coincide, in the same way as it would be conceivable for the main plane H to be arranged below the base plane B with respect to  FIG. 1 . In this case, the openings  6  are arranged further away than the base plane B of the holding device  1  from the end sections of the throughflow tubes (not shown). 
     The reference symbol  21  denotes a partition which separates the respective openings  6  into a left-hand-side region and a right-hand-side region. More precisely, the entire holding device  1  is separated into a left-hand-side region and a right-hand-side region. 
     Here, said separation can be substantially symmetrical, though embodiments are also possible in which the separation is asymmetrical. 
     Here, the partition  21  bears in each case alternately against steps  22 , more precisely against the sections  22   a  and  22   b  of the steps  22 , which run substantially parallel to the plane of the partition. Adjacent thereto, the steps  22  also have sections  24   a  and  24   b  which run substantially perpendicular with respect to the plane of the partition, and sections  25   a  and  25   b  which run obliquely with respect to the plane of the partition  21 . 
     In this embodiment, the partition bears in each case against the narrowed region  6   a  of the openings  6 . In addition, the partition  21  can have slots (not shown) which hold the ends of the throughflow tubes (likewise not shown) at least in the region of the opening  6 . 
     As a result of the absence of borders or collars in the regions  6   a  of the openings  6 , it is possible for the slots in the partition to also be smaller or more precisely matched, which ultimately leads to an increased degree of impermeability of the respective connections between the throughflow tubes and the partition. 
     As a result of the use of the partition, the holding device  1  and therefore the cover or the base of the heat-exchanging device is separated into a left-hand-side and a right-hand-side partial region. Said separation is preferably continued further into the throughflow devices (not shown) which are inserted into the holding device. 
     The production-related difficulty is in the production or configuration of the transition regions of the two processes in the region of the openings or rim holes. Said transition region may not have any large solder gaps after the joining process, that is to say after the insertion of the throughflow tubes into the openings, in order not to adversely affect the subsequent soldering process and to prevent the occurrence of leakages after assembly. 
     For this purpose, coordinated tools are used for the individual shaping processes, that is to say, in particular but not exclusively, for the punching and tearing processes, such as for example coordinated punches and dies. 
     Here, the tools are preferably selected so as to have an overlapping region between those regions in which the respective processes are applied, that is to say that in the transition regions, the material is machined by both processes or by both tools. 
     It is for example possible by means of suitable dimensioning of the tools to provide that, in the case in which initially a punching process and subsequently a tearing process are carried out, the already-punched regions of the openings are not subjected to any further forces, which lead to a deformation of the already-punched material, by the tearing process. 
       FIG. 2  shows a further embodiment of the base device  1  of the heat-exchanging device according to the invention in a perspective view from above. The base device  1  has rim holes  6  which are surrounded by collars  8 . Here, the collars  8  are connected by means of bevels  12  to a base  13  of the base device  1 . Illustrated approximately centrally and transversely with respect to the rim holes  6  for holding corresponding flat tubes (not illustrated) is a base section  14  with steps  22 , which are situated opposite one another, for holding the partition  21 . Arranged at the outer ends of the collars of the rim holes  6  is in each case one gap. The rim holes  6  with the collars  8  and the gap  11  can be generated by means of a combined tearing and punching process as described above. 
       FIG. 3  shows the base device  1  of  FIG. 2  from below, that is to say in a rear view. In addition to the rim holes  6  and the base section  14  with the steps  22  are the narrowed central regions  6   a  of the rim holes  6 . 
       FIG. 4  and  FIG. 5  correspond to  FIGS. 2 and 3 , in a further perspective view. For explanation, reference is therefore made to the preceding description of  FIGS. 2 and 3 . 
       FIG. 6  shows the heat-exchanging device according to the invention using the base device of  FIG. 2 . Flat tubes or throughflow devices  15  having flow chambers  16  and  17  and a narrowed region  18 , which separates the flow chambers  16 ,  17  from one another, are inserted into the base device  1  through the rim holes  6  with their narrowed central regions  61 . A partition  21  with slots  23  is inserted into the base section  14 , which partition serves to separate the flow into two regions. Here, the partition  21  is supported by the steps  22 . The slots  23  of the partition  21  serve to hold the narrowed regions  18  of the flat tubes  15 . 
       FIG. 7  shows the device as per  FIG. 6  composed of the base device  1 , a plurality of inserted flat tubes and a partition  21 . 
       FIG. 8  shows a section perpendicularly with respect to the inserted partition  21  through the base device  1  of  FIG. 2 , with the section running through a slot  23  of the partition  21  and therefore along a rim hole  6 . 
       FIG. 9  shows a further section perpendicularly with respect to the inserted partition  21  through the base device  1  of  FIG. 2 , with the section running through a region of the partition  21  without a slot, and therefore not along a rim hole  6 , such that the base  13  of the base device  1  can be seen. 
       FIG. 10  shows a further embodiment of a base device  1  having rim holes  6  which are surrounded by collars  8  which are arranged on bevels  12 , with the bevels  12  producing the connection to the base  13  of the base device  1 . Similarly to the base device of  FIG. 2 , a base section  14  which runs substantially perpendicular to the rim holes  5  and has steps  22 , which are arranged opposite one another, is provided, which base section  14  serves to hold a partition (not illustrated). In contrast to the embodiment of  FIG. 2 , a further holding section  30 , which runs perpendicular to the base section  14 , is provided, which holding section  30  has guide faces  31   a ,  31   b ,  31   c  and  31   d  which stand perpendicular to the plane of the base device  1 . By means of the holding section  30  and the guide faces  31   a ,  31   b ,  31   c  and  31   d , it is possible for a partition to be inserted into the base device  1 , which partition is arranged parallel to the rim holes  6 . If a further partition of corresponding configuration is likewise to be inserted into the base section  14  which is provided for holding a partition, then it is possible for the flow to be divided into four. The arrangement of two holding devices for partitions, specifically the base section  14  and the holding section  30 , otherwise opens up the possibility of the arrangement of a partition perpendicular or parallel to the rim holes  6 . 
       FIG. 11  shows the base device  1  of  FIG. 10  in a rear view. It can be seen that, in the rear view, the intersection of the two holding sections  14  and  30  is in the shape of a cross  32 . 
       FIG. 12  is an exploded illustration of an embodiment of the heat-exchanging device according to the invention having a base device  1  as per  FIG. 10 , a further partition  33  and a plurality of flat tubes  15 . The further partition  33  runs in the direction of the elongate rim holes  6  and leads to a separation of the flow into two regions if only said further partition  33  is used. If a corresponding “first” partition  21  (not illustrated) is additionally inserted into the base section  14 , then the flow is divided into four. 
       FIG. 13  is an exploded illustration, in a rear view, of the embodiment of the heat-exchanging device according to the invention of  FIG. 12  having a base device  1  as per  FIG. 10 , a further partition  33  and a plurality of flat tubes  15 . It is possible to see the cross  32  which is arranged approximately centrally in the base device  1 , so that a partition can be inserted which runs either in the direction perpendicular or in the direction parallel to the rim holes  6 . 
       FIG. 14  shows the heat-exchanging device as per  FIG. 28  in the assembled state having a partition  31 , a base device  1  and a plurality of flat tubes  40 . 
       FIG. 15  finally shows a cross section through a base device  1  which is provided with a further partition  33  along the base section  14  of  FIG. 10 , such that the narrowed regions  6   a  of the rim holes  6  can be seen in the base  13 .