EP2371466B1 - Method for producing a metal part - Google Patents

Description

The present invention relates to a method for producing a metal part, in particular floor for a heat exchanger, according to the preamble of claim 1 and a heat exchanger with such a metal part.

The method will be described in relation to a heat exchanger used in automobiles, for example, in air conditioning systems of a motor vehicle and the like. However, the method can also be applied to other heat exchangers or intercoolers.

In most cases, the trays for heat exchangers have openings through which the flow tubes can be inserted. For the production of these openings, which are also referred to as passages, several production methods are known from the prior art. For example, these passages can be produced by means of punching.

The advantages of punching are that the production is relatively simple, the opening or the passage thus produced has a high degree of accuracy and any sectional shape geometry can be produced.

The disadvantage, however, is that when punching the passages material is lost. Another disadvantage is that the previous manufacturing processes are subject to considerable design effort with many manufacturing steps.

The publication EP 0776711 discloses a method of making tube sheets of heat transfer.

The invention has for its object to provide a simplified manufacturing method for creating a metal part of the type mentioned, which also has increased strength values.

This object is achieved by a method having the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

The object is achieved according to the invention in that the method for producing a metal part, in particular bottom of a heat exchanger, with a plurality of openings for receiving flow tubes, essentially comprises the following method steps: feeding and cutting to length a strand of material from a metal; partially reshaping the material piece obtained and creating at least one predetermined breaking point in the piece of material; and forming at least one opening with edge region for receiving a flow-through pipe in the region of the predetermined breaking point by at least regional tearing and deformation in the region of the predetermined breaking point. Compared to a wasteful operation of the punching a slot of, for example, at least 2 mm width provides, one wins by the inventive method material that can be used to increase the strength of the metal part and in particular the passages. In particular, the passages or the edge regions can be made higher by the material obtained, since more material is available for the formation of the passages or the edge regions. By the term tearing is meant a process in which the opening is achieved at least temporarily by pulling or tearing. The term breaking point is understood to mean the area which defines the later opening after the breaking process has been applied.

The material strand may be a band or sheet or a profile, it may be present as a roll material or in any other way as an endless or quasi-endless supply of material.

One embodiment provides that the predetermined breaking point can be produced by means of material displacement by an embossing process. For example, the embossing can account for a majority of the material thickness of the piece of material. The embossing runs on at least one side of the main plane of the piece of material. It is also conceivable that both sides of the piece of material are provided with an opposite and substantially the same or similar embossing. The embossments are designed so that they do not fully penetrate the piece of material, which is why no material waste. In any case, the embossments are to be designed so that a simple pulling or tearing of the opening is made possible.

For example, the Anprägevorgang can be done without cutting by means of a punch with an associated die. The material is thus essentially displaced. Other methods and devices for producing a stamping are conceivable.

A further embodiment provides that the predetermined breaking point can have regions with an at least slightly lower material thickness than the rest of the material piece. For example, the predetermined breaking point groove-like with bevelled edges in the piece of material without completely penetrate the piece of material.

For example, the steps according to method step b.), Namely, the regional forming and creating the predetermined breaking point, substantially simultaneously or in a single operation. For example, it may be provided in the reshaping step to angle or bead over portions of the piece of material (for example side walls). For example The work steps can be performed by a tool that masters both work steps.

For example, the steps according to method step c.), Namely the tearing and forming process, can be carried out essentially simultaneously or in one operation. For example, it may be provided in the forming step to form the edge regions of the openings. For example, the work steps can be performed by a tool that masters both work steps.

The completion of simultaneously feasible steps or the possibility of using cheaper and simpler tools means that the basic investment in tools can be significantly reduced and the manufacturing cost of the metal part can be reduced.

One embodiment provides that the edge region of the openings can be produced by a non-cutting shaping process, wherein the edge region can protrude at least partially from the main plane of the material piece. For example, the chipless forming process may include a bending or deep drawing process. The classic and preferred method is thermoforming with rigid tools. For deep drawing, for example, presses are used. The pressing force required for forming is conducted by means of a punch on the bottom of the metal part to be produced. A hold-down can avoid wrinkling by upsetting. With the stamp, the piece of material is pressed for example by a die.

Preferably, but by no means necessarily, the edge region may protrude substantially perpendicularly from the main plane of the piece of material. This means that the flow tubes are pushed through the openings, and the edge areas in the same direction in which the flow tubes are pushed through the openings, protrude from the main plane.

However, the edge regions can also run obliquely with respect to the main plane and form, for example, chamfers which facilitate the assembly, in particular the connection with the flow tubes.

A further preferred embodiment provides that the opening with the edge region may have an elongated shape. Under elongated is understood that the opening may have a predetermined length and compared to this length a significantly reduced width. This is particularly advantageous if the flow tubes are flat tubes whose ends likewise have an elongated cross section.

Overall, it should be noted that the new process is characterized by a reduction in the work steps compared to known production methods and also offers the possibility to use more cost-effective tools.

Furthermore, the invention is directed to a method for producing a heat exchanger, wherein in a method step, a metal part is produced according to one of the preceding method steps and then the flow tubes at least partially with the metal part by means of a connecting means (eg, solder) or connection method, such as a soldering or welding process, be connected.

Further advantages, features and details of the invention will become apparent from the following description in which reference is made to the drawing embodiments of the invention are described. The features mentioned in the claims and in the description may each be essential to the invention individually or in any desired combination.

• Fig. 1 die schematische Darstellung einzelne nachfolgender Verfahrens" schritte zur Schaffung eines erfindungsgemäßen Metallteils;
• Fig. 2 die schematische Teildarstellung eines Metallteils für einen Wärmetauscher mit einer beidseitigen Anprägung;
• Fig. 3 die schematische Teildarstellung eines Metallteils für einen Wärmetauscher mit einer einseitigen Anprägung;
• Fig. 4 die schematische Seitenansicht auf ein fertiges Metallteil.

Show it:

• Fig. 1 the schematic representation of individual subsequent process "steps to provide a metal part according to the invention;
• Fig. 2 the schematic partial view of a metal part for a heat exchanger with a two-sided embossing;
• Fig. 3 the schematic partial view of a metal part for a heat exchanger with a one-sided embossing;
• Fig. 4 the schematic side view of a finished metal part.

Fig. 1 shows a schematic representation of individual subsequent process steps for the creation of a metal part 1, here ground for a heat exchanger, wherein the same components carry identical reference numerals, and wherein the method (in spite of a mirror image of two metal parts) is described only with reference to a metal part 1,

In a first method step 1 ', the method initially proceeds from a suspended piece of material 2, which is essentially plate-shaped, wherein the cutting-off process can include the provision of a notch 2'.

In a next method step 1 ", the piece of material 2 is formed by partially reshaping the piece of material 2, forming the side walls 3 and 4, and simultaneously creating a plurality of predetermined breaking points 5 according to method step 1". The predetermined breaking points 5 are have been produced by means of a Anprägevorgangs, wherein the predetermined breaking points 5 are formed so that they do not completely reach through the piece of material 2 in the main plane H, and thus no material waste arises. For example, the predetermined breaking points 5 can be produced by a stamping or stamping process with at least slight material displacement.

A next step 1 "'shows the piece of material 2 after a tearing and forming process to form the now finished passages (openings) 6 with edge region 7. The edge regions 7 extend perpendicularly from the main plane H of the piece of material 2 out and serve the attachment or Supporting the flow tubes which can be introduced into the passages 6. For example, the passages 6 can be formed by means of a forming process, which may include a deep-drawing operation, for example by means of a hydraulic press, wherein the deep-drawing process can involve the simultaneous impressing of further phases 8. Using a simultaneous example Breaking process thus the opening or, the passage 6 is formed.

The illustration under 1 does not show a new process step but serves to illustrate the gain increase D. obtained by material saving.

Fig. 2 shows the schematic partial view of a metal part 9, in particular bottom for a heat exchanger, with an embossment provided on both sides. The embossments for forming a predetermined breaking point 10 extend on both sides of the main plane H 'of the metal part 9. The two embossments are formed so that between the embossments an unembossed material web 11 stops, wherein the material web 11 is torn in a later tearing process, whereby the predetermined breaking point 10 forms the later opening. The embossings have oblique or phase-like Edge regions 12, 13 which open in circular end regions 14, 15.

Fig. 3 shows the schematic partial view of a metal part 16, in particular bottom for a heat exchanger, with an embossment provided on one side. The one-sided embossing forms a predetermined breaking point 17, which does not fully penetrate the metal part 16 in the main plane H "The predetermined breaking point 17 is designed so that the material web 18 stops, which is torn in a later tearing process, whereby the predetermined breaking point 17 is the later Opening forms.

Fig. 4 shows the schematic side view of a finished metal part 1 according to process step 1 "in Fig. 1 ,

The representation of the metal part 1 shown here is intended to illustrate the possible increase of the passage 6, wherein the area D1 shows the passage height achievable by punching, while the area D2 shows the passage height achievable by a tearing process.

By bypassing the Lochungsvorgangs (no material waste) so material can be obtained, which as shown here, can be used to increase the passage and thus to increase the strength of the passages 6.

Claims (10)

1. A method for producing a metal part (1, 9, 16), in particular a base of a heat exchanger, having a plurality of openings (6) for receiving flow pipes, said method comprising the following method steps:

   a) feeding and cutting to length a material strand made of a metal;
   characterised in that the following method steps are further carried out:

   b) forming, in some regions, the obtained material piece (2) and creating at least one predetermined breaking point (5, 10, 17) in the material piece (2);

   c) forming art least one opening (6) with an edge region (7) for receiving a flow pipe in the region of the predetermined breaking point (5, 10, 17) by rupturing and forming, at least in some regions, in the region of the predetermined breaking point.
2. The method according to claim 1, characterised in that the predetermined breaking point (5, 10, 17) is produced by means of material displacement by an embossing process.
3. The method according to at least one of the preceding claims, characterised in that the embossing process takes place in a now-cutting manner by means of a punch with a respective die.
4. The method according to at least one of the preceding claims, characterised in that the predetermined breaking point (5, 10, 17) has regions with an at least sightly smaller material thickness than the rest of the material piece (2).
5. The method according to at least one of the preceding claims, characterised in that the steps according to method step b) are carried out substantially at the same time.
6. The method according to at least one of the preceding claims, characterised in that the steps according to method step c) are carried out substantially aft the same time.
7. The method according to at least one of the preceding claims, characterised in that the edge legion (7) of the openings (6) is produced by a non-cutting shaping method, wherein the edge region (7) protrudes, at least in some regions, from the main plane (H, H' , H") of the material piece (2).
8. The method according to at least one of the preceding claims, characterised in that the edge region (7) protrudes substantially perpendicular from the main plane (H, H', H'') of the material piece (2).
9. The method according to at least one of the preceding claims, characterised in that the opening (6) has an elongate form.
10. A method for producing a heat exchanger, characterised in that, in one method step, a metal part (1, 9, 16) according to one of the preceding claims is produced and the flow pipes are then connected, at least in some portions, to the metal part (1, 9, 16) by means of a connection means.

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