Method for throughput joining and device therefor

Abstract

A method and a device for the throughput joining of two singly curved surfaces (Z1, Z2) of two parts (T1, T2) are proposed, in which a mandrel (DO) is positioned below the first surface (Z1), which mandrel has a movable punch (ST) inside. A die (MT) having a deep-drawing opening (TÖ) is positioned above the second surface (Z2). The punch (ST) is moved along the surface normals of the two surfaces (Z1, Z2) so that material is displaced from the respective surfaces (Z1, Z2) into the deep-drawing opening (TÖ), wherein the deep-drawn and squeezed surface portion of the first surface (Z1) engages behind the remaining part of the second surface (Z2) for the form-fitting interlocking of the two surfaces (Z1, Z2). The plunger (ST) blocks the outflow of a medium from a channel (KA) within the mandrel (DO) until the pressure force (D) of the medium acting on the plunger (ST) is large enough to move the plunger (ST).

Description

[0001] The invention relates to a method and a device for the throughput joining of two simply curved surfaces of two parts, as well as a heat exchanger containing the two parts.

[0002] It is known to solder or weld simply curved surfaces of two parts. The first part can be, for example, a pipe or a manifold for a heat exchanger and the second part can be a holder. The holder can be used to attach the heat exchanger to the body of a motor vehicle, for example. The second part can have a curved surface that is permanently connected to the first part. Using a welding process, there is a detrimental heat input into the first part as well as the second part. The two parts are often made from an aluminum alloy. The good thermal conductivity of the aluminum alloy can cause the formation of a very wide heat-affected zone. In a heat-affected zone, the properties of the material are generally poorer.Typical problems in the area of a heat affected zone are: increased brittleness, weld cracks, residual stresses, reduced strength and reduced corrosion resistance. This can lead to the parts failing during assembly or operation and can disadvantageously result in high scrap rates. When the two parts are joined using a brazing process, for example hard soldering, a temperature is introduced into the two parts in the brazing furnace. When the two parts are joined in the brazing furnace. The strength of the material of the two parts can deteriorate adversely due to the temperature input during brazing. By using a manufacturing process for the first part, such as extrusion, the strength of the finished tube is higher than the strength of the material in its initial state. At least this increase in the strength of the material of the first part is lost again when a brazing process is used.Furthermore, DE 199 29 375 A1 discloses a method and device for the throughput joining of two superimposed thin, flat plates or flat plate sections from above. Disadvantageously, the disclosed method and device cannot be used to join two curved surfaces of two parts.

[0003] The method according to the invention and the device according to the invention with the features of the independent patent claim have the advantage that two simply curved surfaces of two parts can be connected to one another and heat input into the two parts can be avoided by the method according to the invention.

[0004] The starting point for the invention is a method for throughput joining two parts. Throughput joining is a method for connecting at least two parts. The two parts can be, for example, sheet metal parts, pipes and / or profile parts. The width and length of a part are each much greater than its thickness. A pipe is an elongated hollow body. The length is significantly greater than the diameter and the wall thickness (thickness). Throughput joining belongs to the group of joining methods by forming. A device for throughput joining contains a punch and a die. The parts to be joined can have a first metallic material that is plastically deformable. The die is rigid and has a deep-drawing opening so that the two parts form an overlap and a snap-fastener-like shape is created that connects the two parts in a form-fitting and force-fitting manner.Plastic deformation is the behavior of materials to irreversibly deform under the application of a force after exceeding their elastic limit and to retain this shape after the force has been applied. Below the elastic limit of a material, the part returns to its original shape when the load is removed. The inventive method for throughput joining comprises the following steps: positioning two simply curved surfaces of two parts on top of each other. A simply curved surface is a surface that can be smoothly developed onto a flat plane without compression or tension. Here, a simply curved surface can be the outer surface of a hollow cylinder. The first part can be a tube or a half-tube, for example. The second surface can be simply curved to match the first surface, so that a fit is created between the two surfaces of the two parts.It is possible for the two parts to each be made of an aluminum alloy. The first part can be, for example, a seamless drawn tube or a welded tube made of aluminum. The second part can be an aluminum holder. The second part is positioned above the first part. The two surfaces are each simply curved so that they can be placed on top of each other without leaving gaps. This can be achieved, for example, by the outer diameter of a tube corresponding to the inner diameter of the second surface of a holder. A mandrel is then positioned below the first surface, said mandrel having a movable punch inside. The mandrel can be represented, for example, by an elongated hollow cylinder. The first part and the mandrel can have a common central axis. In this way, a radial direction and a longitudinal direction can be defined.Below the first surface can be defined as being radially further inwards. If the first part is a tube, the mandrel can be pushed into the tube. The punch required for throughput joining is arranged inside the mandrel in such a way that when the mandrel is positioned below the first surface, the punch cannot touch the first surface. A die is then positioned above the second surface, which die has a deep-drawing opening. The deep-drawing opening can be circular with an undercut or rectangular with an undercut. The punch is then moved along at least one of the surface normals of the two simply curved surfaces, so that material from the respective surfaces is displaced into the deep-drawing opening. This process step can be divided into further sub-steps. The materials of the two parts are each at least partially plastically deformed.The deep-drawing opening can have an upper contour and an annular channel on the punch side. The respective material of the respective surfaces can be simultaneously sunk and pushed through the deep-drawing opening in a first partial step. The respective material of the respective surfaces can then be compressed and widened. The upper contour of the deep-drawing opening can then be filled and the annular channel on the punch side can be filled and laterally flowed behind. This results in the positive interlocking of the two surfaces. The deep-drawn and squeezed surface portion of the first surface engages behind the remaining part of the second surface. The punch is then moved back to its starting position. The die and mandrel are then removed. A push-button-like joining connection point is produced using the method according to the invention.The two parts can comprise a first metallic material, wherein the two parts can each have a constant strength which can be greater than or at least equal to the strength of the two parts before application of the method according to the invention. It is possible for an aluminum alloy to be used as the first material. Strength is understood to be the mechanical load-bearing capacity of a part until it fails. A fracture or excessive permanent deformation of the part can, for example, trigger this failure. Material-bonding processes such as welding or soldering influence the strength of the part, at least in some areas. When two parts are welded, the heat generated can create a disadvantageous heat-affected zone in which the strength can be significantly reduced.When two parts are joined using a brazing process, the heat from the brazing furnace can reduce the strength of the two parts. This reduction in strength would have to be compensated for, for example, by adversely increasing the wall thickness of the part.

[0005] Since the use of the method according to the invention advantageously results in no heat being introduced into the two parts, the disadvantageous formation of heat-affected zones and a disadvantageous reduction in strength can be avoided. Advantageously, the disadvantageous notch effect that occurs with cutting processes can be avoided by using the throughput joining process. For these reasons, a joint can be produced that has advantageously high static and dynamic strength. The advantageous arrangement of the punch within the mandrel, which is positioned below the first surface, and the positioning of the die above the second surface, achieves two-sided accessibility, which is necessary for carrying out a throughput joining process.A particularly high strength of the joint can be achieved if the first part is thinner than the second part or the first part is softer than the second part, i.e. the first part is more formable than the second part.

[0006] A preferred embodiment of the method according to the invention is characterized in that the piston blocks the outflow of a medium from a channel within the mandrel until the compressive force of the medium acting on the piston is so great that it moves the piston. It is conceivable that the medium is compressed air. Alternatively, it is conceivable that the medium is hydraulic oil. The channel within the mandrel can be connected to a compressed air generator, such as a compressor. The piston can be mounted in the channel in such a way that a movement of the bearing along the length of the mandrel can be converted into a movement of the piston perpendicular to the mandrel. The mandrel can contain guides or channels to guide the medium to the piston. A surface of the piston is acted upon by the medium so that the compressive force acts on the piston and thus the desired movement is achieved.If the medium is no longer applied to the surface of the punch, the compressive force is no longer applied to the punch and the punch returns to its original position due to gravity. The channel in the mandrel can have a guide for the medium, by means of which the surface of the punch can be subjected to the medium in a targeted manner. Due to the advantageous arrangement of the movable punch within the mandrel, the punch required for the process can be retired within a closed part. The direction of movement of the punch and thus also the joining direction is from the inside out. If the first part is a closed pipe, the mandrel is retracted into the pipe and then the punch is moved using the compressive force.

[0007] A further preferred embodiment of the method is characterized in that, through at least partial plastic deformation of the material of the two surfaces, a joining connection point is created which is located at least partially above and / or outside the two surfaces. As described above, the joining direction of the method according to the invention is from the inside out. Due to the advantageous design of the joining connection point at least partially above and / or outside the two surfaces, damage to the two parts when removing the mandrel can advantageously be avoided. Jamming or similar interference between the two parts and the mandrel can also be avoided. Advantageously, the positioning of the mandrel can take place laterally or along an axis parallel to the two parts. This also increases the process reliability of the method according to the invention.

[0008] A further preferred embodiment of the method according to the invention is characterized in that a direction of movement of the punch can run essentially along at least one of the surface normals of the two surfaces. A singly curved surface can have a surface normal. A surface normal can be perpendicular to the singly curved surface. If the surface normals of the two surfaces and the direction of movement of the punch essentially coincide, the position finding for the punch and the die can be simplified and the process reliability of the method according to the invention can thus be further increased. By essentially is understood a possible length deviation of ±2 mm and / or a possible angular deviation of ±10 °. This deviation can appear as a displacement and / or as a rotation.

[0009] A further preferred embodiment of the method according to the invention is characterized in that the first part can be a closed tube and the wall of the tube consists at least partially of the first surface, wherein the tube and the mandrel are positioned such that their central axes are substantially identical. Since the central axes of the tube and mandrel are identical, jamming or snagging when extending and retracting the mandrel into the closed tube can be avoided. Since the punch required for the method according to the invention is arranged inside the mandrel and the necessary die above the second part and thus outside the tube, the method according to the invention can be used for closed tubes. Since the resulting joint is at least partially formed outside and / or above the two surfaces, damage to the tube when the mandrel is extended from the tube can advantageously be avoided.It is particularly preferred if the joint is formed outside the inner diameter of the tube. It is possible for the tube to have a circular diameter. Alternatively, it is conceivable for the tube to be formed as a flat tube with an oval cross-section.

[0010] A further preferred embodiment of the method according to the invention is characterized in that the die can be virtually stationary and the volume of the deep-drawing opening can be unchangeable. Virtually stationary means that the die is virtually immobile compared to the punch. In this way, simple geometries can be used for both the punch and the deep-drawing opening. The die can be easily positioned over the two parts and can also be used to clamp the two parts together. The unchangeable volume of the deep-drawing opening ensures that the respective material of the respective surfaces is almost completely pressed into the deep-drawing opening.

[0011] In a first embodiment of the device according to the invention for carrying out the method according to the invention, the channel has an opening for the outflow of the medium and is connected to a pressure generator. The piston can be moved by means of the pressure force acting on the piston. The medium can be compressed air, which is compressed by means of a pressure generator. The pressure generator can be a compressor, for example. Once the piston has been moved along its direction of movement by means of the pressure force acting on it, the medium can flow under the piston and out of the mandrel through an opening. The pressure of the medium can hold the piston in the extended position. When the pressure generator is switched off, the pressure force is removed and the piston returns to its original position by gravity. The device according to the invention can have a frame.The die can be connected to the frame via a mechanism such that the die can be lowered onto the two parts and removed again. The mandrel can be connected to the frame via a mechanism such that the mandrel can be positioned below the two surfaces. The mandrel can have a central axis. The first part can have a central axis. The first part can be clamped stationary in the device and the mandrel can be positioned below the first surface such that the central axis of the mandrel and the first part are at least essentially identical. The punch can have at least one axis of movement. The punch is movable along this axis of movement. The axis of movement of the punch can be perpendicular to the central axis of the mandrel. With this arrangement, a surface normal of the first surface of the first part coincides with the axis of movement of the punch.The second part can be positioned over the first part so that the surface normal of the second surface coincides with the movement axis. The die can be positioned over the two surfaces so that the two surfaces are at least pre-clamped.

[0012] In a second embodiment of the device according to the invention, the punch can be rotatably mounted in the channel. In this way, it is possible to generate the compressive force acting along the central axis into a perpendicular movement of the punch along the punch's movement axis, directed outward from the central axis. In this way, the respective surface portions of the two surfaces can be formed into the deep-drawing opening by means of the punch, thus creating the joining connection point. The movement of the punch is directed from the inside out.

[0013] In a further embodiment of the device according to the invention, the mandrel can have a lateral opening through which the punch can be moved. The lateral opening can have an axis, and this axis and the movement axis of the punch can coincide. The lateral opening can have a circular diameter. The diameter can be large enough for the punch to be moved at least partially through the opening.

[0014] A further preferred embodiment of the device according to the invention is characterized in that the lateral opening of the mandrel can be fluidically separated from the environment by the first surface. A connection can be created between the die and the first surface when the die is positioned over the two surfaces. This can create a force that is opposite to the joining direction (directed towards the central axis of the mandrel). The resulting contact pressure of the die on the first surface can fluidically separate the lateral opening from the environment and thus seal it. The seal can be further improved by at least one additional seal, for example a rubber seal. Fluidically separated means that no quantities or only negligible quantities of a medium can pass through the connection.

[0015] In a further embodiment of the device according to the invention, the deep-drawing opening in the die can be designed as a blind opening in the radial and axial directions of the deep-drawing opening. The deep-drawing opening can therefore be designed such that it does not completely penetrate the die. The deep-drawing opening can have at least a circular diameter, so that a circular, point-shaped joint connection point can be created. The deep-drawing opening can have a contour at its base to further improve the strength of the joint connection point. Such a circular, point-shaped joint connection point can have the same strength in all planes and can be gas-tight.

[0016] In a further embodiment of the device according to the invention, the punch can have a circular working pin that at least partially extends into the deep-drawing opening. The working pin can have a cylindrical shape or a conical shape. Since the deep-drawing opening can have a circular shape and the working pin can also have a circular shape, a circular, point-shaped joining connection point can be created. The strength of such a circular, point-shaped joining connection point can be further increased, and the gas tightness in the punch-side plane and in the die-side plane of the joining connection point can be further increased.

[0017] In a first embodiment according to the invention, the heat exchanger can contain at least two parts that have been connected to one another by means of the method according to the invention. It is possible for the first part to be a half-pipe and for the second part to be a holder. With the holder, the heat exchanger can be connected, for example, to another component or the body of a motor vehicle. The outer surface of the half-pipe can be the first surface and the holder can have the second surface. The second surface of the holder can be simply curved to match the first surface (outer surface), so that a fit is created between the two surfaces. In this way, the half-pipe and the holder can be permanently connected to one another using the method according to the invention. A half-pipe can, for example, be produced by splitting a pipe.

[0018] In a second embodiment of the heat exchanger according to the invention, the first part can be a tube and the second part can be a holder. With the holder, the heat exchanger can be connected to another component or the body of a motor vehicle, for example. The diameter of the tube can be greater than 20 mm. The tube can be a closed tube, which for example comprises an aluminum alloy and is drawn seamlessly. The heat exchanger according to the invention can have further tubes through which a second medium can flow and which can be acted upon by a third medium, so that a transfer of heat can take place between the second and the third medium. The further tubes can be represented as flat tubes and corrugated fins can be arranged between the flat tubes to increase the surface area for heat transfer.The tube as the first part can be a collecting pipe via which the second medium can be distributed to the other pipes and collected again. Alternatively, the heat exchanger according to the invention can be connected to a refrigerant circuit via the pipe. The outer surface of the tube can be the first surface and the holder can have the second surface. The second surface of the holder can be simply curved to match the first surface (outer surface of the tube) so that a fit is created between the two surfaces. The tube and the holder can be connected to one another using the method according to the invention and thus the heat exchanger according to the invention has at least one joining connection point. It is possible for more than two holders to be connected to the tube using the method according to the invention and thus the heat exchanger according to the invention has more than two joining connection points.By using the method according to the invention, a joint can advantageously be produced that exhibits high static and dynamic strength. The disadvantageous formation of heat-affected zones on the two parts or a disadvantageous reduction in the strength of the two parts is avoided, since no or almost no heat is generated during use of the method according to the invention.

[0019] The refrigerant circuit according to the invention for a motor vehicle can have at least one heat exchanger according to the invention. The heat exchanger according to the invention can have tubes through which a refrigerant flows and which are acted upon by a further medium (for example air), so that a transfer of heat can take place between the refrigerant and the further medium. The tubes can be fluidically connected to two collectors in order to distribute the refrigerant between the tubes and to collect it again. One of the two collectors is in each case the first part. Two holders are in each case connected to the collector as the second part by means of the method according to the invention. By means of the holders, the heat exchanger according to the invention can, for example, be fastened to the body of the motor vehicle.The refrigerant circuit according to the invention can have the following components: a heat exchanger according to the invention as a condenser for condensing a refrigerant, a collector for collecting and storing the refrigerant, an expansion valve for expanding the refrigerant, an evaporator for evaporating the refrigerant, a compressor for compressing the refrigerant, and the connecting lines. A refrigerant flows through the refrigerant circuit according to the invention. It is conceivable that R1234yf, for example, flows through the refrigerant circuit. Alternatively, it is possible for carbon dioxide (R744), propane (R290), or R134a to flow through the refrigerant circuit. With the help of the evaporator, heat can be extracted from the interior of a motor vehicle, for example, and this heat can be released to the environment via the condenser. Fig. 1: Schematic representation in section of the device for carrying out the method according to the invention in a first embodiment according to the invention. Fig. 2: Sectional view of two parts connected to each other after carrying out the method according to the invention. Fig. 3.1: Top view of a first part and three parts permanently connected thereto in a first embodiment according to the invention after carrying out the method according to the invention. Fig. 3.2: Top view of a first part and three parts permanently connected to it before carrying out the method according to the invention.

[0020] In Fig. 1, the device 100 for carrying out the method according to the invention is shown in section in a first embodiment according to the invention. The device 100 according to the invention has the mandrel DO. The mandrel DO is designed as a hollow cylinder, so that the mandrel DO has a channel KA inside and the central axis MS. The punch ST required for the method according to the invention is arranged inside the channel KA and closes the channel KA in a fluid-tight manner in the starting position. The first part T1 is a tube, and here a closed tube in the form of a hollow cylinder. The mandrel DO is inside the first part T1. The tube can, for example, be pushed over the mandrel DO. The first part T1 can comprise an aluminum alloy and, for example, be manufactured as a seamless drawn tube. The central axis MS coincides with the central axis of the first part T1. The first part T1 is clamped using a clamping element (not shown).The second part T2 can be made of aluminum alloy. The mandrel DO has a lateral opening through which the punch ST can move along the movement axis AS. The movement axis AS is perpendicular to the central axis MS. The second part T2 is arranged above the first part T1 such that the surface normal of the second surface Z2 coincides with the movement axis AS. The first part T1 is shown as a tube and the first surface Z1 is the outer surface of the tube. The first surface Z1 is simply curved as the outer surface of the tube (first part T1) and the surface normal of the outer surface essentially coincides with the movement axis AS. The second surface Z2 is simply curved. The second surface Z2 of the second part T2 is arranged above (seen from the central axis MA) the first surface Z1 of the first part T1. The die MT is arranged above the two surfaces Z1, Z2.The die MT is pressed onto the two parts T1, T2 during implementation of the method according to the invention. The die MT has the deep-drawing opening TO. The deep-drawing opening TO is designed as a circular blind hole. The medium M flows through the channel KA. The medium M is compressed air. This can be generated, for example, by a pressure generator (not shown) that is fluidically connected to the channel KA. The punch ST blocks the medium M from flowing out of the channel KA within the mandrel DO until the pressure force of the medium M acting on the punch ST is so great that it moves the punch ST along the movement axis AS. In this way, a force running along the central axis MS is converted into a movement along the movement axis AS, which movement axis is essentially perpendicular to the central axis MS and directed outwards.The punch ST is moved outwards through a lateral opening in the mandrel along the movement axis AS. The circular, conical working pin AZ of the punch ST forms the respective surface portions of the two respective surfaces Z1, Z2 into the deep-drawing opening TO of the matrix MT. The resulting joint, not shown, is formed from the inside out. The punch ST is mounted in the mandrel DO by means of a swivel joint. Once the pressure force of the medium M is removed, the punch can return to its original position by means of gravity. The medium M flows out of the channel KA via the opening O when the punch ST has moved outwards along the movement axis AS, since the lateral opening is fluidically separated from the environment at least by the first surface Z1. The channel KA of the mandrel DO is narrowed by means of the guide F and one surface of the punch ST is specifically exposed to the medium M.Essentially, we understand a possible length deviation of ±2 mm and / or an angular deviation of ±10°. This deviation can be in the form of displacement or rotation.

[0021] In Fig. 2, the two parts T1, T2 are shown in section, connected by means of the joining connection point VB according to the invention. The first part Z1 is stamped as a closed tube and can form part of an inlet line or outlet line for a heat exchanger 200 according to the invention. Since the first part Z1 is designed as a tube, the first surface Z1 is simply curved as the outer surface of the tube. The second part Z1 has the simply curved surface Z2 and can be stamped as a holder. The second surface Z2 is simply curved to match the first surface Z1, so that a fit is created between the two parts T1, T2. This is achieved by the outer diameter of the tube (first part) and the inner diameter of the second surface Z2 of the second part T2 essentially matching. The surface normals of the two surfaces Z1, Z2 each essentially coincide with the movement axis AS of the punch (not shown).The central axis MS forms the central axis of the first part T1. The movement axis AS is essentially perpendicular to this. The joining connection point VB is circular and point-shaped. The joining connection point VB is advantageously located outside the first part T1 and is pronounced outwards, i.e. away from the central axis MS. The diameter of the tube that forms the first part T1 can be greater than 25 mm. Advantageously, since the joining connection point VB is pronounced outwards, the mandrel (not shown) can be extended from the first part T1 without snagging or damaging the first part T1.

[0022] In Fig. 3 shows a plan view of a first part T1 and three second parts T2 before and after carrying out the method according to the invention. The first part T1 is designed as a closed tube. The first surface Z1 is the outer surface of the tube and is simply curved. The three second parts Z1 each have the second surface Z2. The second parts T2 are each of different sizes. The second surface Z2 is each simply curved to match the first surface Z1, so that a fit is created between the first part T1 and the three second parts T2. This is achieved by the outer diameter of the tube (first part T1) and the inner diameters of the second surfaces Z2 of the second parts T2 essentially matching. The heat exchanger 200 according to the invention has the first part T1 and the second parts T2.

[0023] Shown in Fig. 3.1 shows a top view of a first part T1 and three second parts T2 after the inventive method has been carried out. The three joining points VB are each formed from the inside out, and the three joining points VB are each formed in a circular, point-shaped manner. Shown in Fig. 3.2 Top view of a first part T1 and three second parts T2 before carrying out the method according to the invention. List of reference symbols 100 Device for carrying out the method according to the invention 200 heat exchangers comprising two parts joined by the method according to the invention Z1, Z2 each simply curved surfaces T1, T2 Two parts joined by the method according to the invention RO pipe containing the first simply curved surface VB Emerging joint connection point DO mandrel of the device MT die of the device KA canal within the spine ST stamp inside the mandrel AZ working pin of the punch TO deep drawing opening of the die SO lateral opening of the mandrel O Opening of the thorn M Medium that flows through the channel of the mandrel BR Direction of movement of the stamp AS movement axis along which the stamp is moved MS common central axis of the mandrel and the first part F Guide for the medium QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 199 29 375 A1

[0002]

Claims

[1] A method for throughput joining comprising the following steps: - Positioning of two simply curved surfaces (Z1, Z2) of two parts (T1, T2) on top of each other - Positioning a mandrel (DO) below the first surface (Z1) having a movable punch (ST) inside. - Positioning a die (MT) above the second surface (Z2) which has a deep-drawing opening (TÖ) - Moving the punch (ST) along at least one of the surface normals of the two simply curved surfaces (Z1, Z2) so that respective material is displaced from the respective surfaces (Z1, Z2) into the deep-drawing opening (TÖ) - whereby, for the positive interlocking of the two surfaces (Z1, Z2), the deep-drawn and squeezed surface portion of the first surface (Z1) engages behind the remaining part of the second surface (Z2) - Return the stamp (ST) to its starting position - Removal of the die (MT) and the mandrel (DO) [2] Method according to claim 1, characterized by that the stamp (ST) blocks the outflow of a medium (M) from a channel (KA) within the mandrel (DO) until the pressure force of the medium (M) acting on the stamp (ST) is so great as to move the stamp (ST). [3] Method according to claim 1 or 2, characterized by that, under at least partial plastic deformation of the material of the two surfaces (Z1, Z2), a joining connection point (VB) is created which is at least partially present above and / or outside the two surfaces (Z1, Z2). [4] Method according to claim 1, 2 or 3, characterized by that a direction of movement of the stamp (ST) is substantially along at least one of the surface normals of the two surfaces (Z1, Z2). [5] Method according to claim 1 or 2, characterized bythat the first part (T1) is a closed tube and the wall of the tube consists at least partially of the first surface (Z1), wherein the tube and the mandrel (DO) are positioned so that their central axes (MA) are substantially identical. [6] Method according to claim 1 or 2, characterized by that the die (MT) is almost stationary and the volume of the deep-drawing opening (TO) is unchangeable. [7] Device (100) for carrying out the method according to one of claims 1 to 6, characterized by that the channel (KA) has an opening (O) for the outflow of the medium (M) and is connected to a pressure generator. [8] Device (100) according to claim 7, characterized by that the stamp (ST) is rotatably mounted in the channel (KA). [9] Device (100) according to claim 7 or 8, characterized by that the mandrel (DO) has a lateral opening (OS) through which the punch (ST) is moved. [10] Device (100) according to claim 7, 8 or 9, characterized by that the lateral opening (OS) of the mandrel (DO) is fluidically separated from the environment by the first surface (Z1). [11] Device (100) according to claim 7, 8, 9 or 10, characterized by that the deep-drawing opening (TO) in the die (MT) is designed as a blind opening in the radial and axial direction of the deep-drawing opening (TO). [12] Device (100) according to claim 7, 8, 9, 10 or 11, characterized by that the punch (ST) has a circular working pin (AZ) which is at least partially immersed in the deep-drawing opening (TO). [13] Heat exchanger (200) comprising at least two parts (T1, T2) which are connected to one another by means of the method according to one of claims 1 to 6. [14] Heat exchanger (200) according to claim 13, characterized bythat the first part (T1) is a pipe and the second part (T2) is a holder for connecting the heat exchanger (200) to another component, wherein the diameter of the pipe is greater than 20 mm. [15] Refrigerant circuit for a motor vehicle comprising at least one heat exchanger (200) according to claim 13.

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