DE102012014073B3 - Method for making slots in pipe wall, involves piercing set of stampers through pipe wall for producing set of slots, and piercing another set of stampers through pipe wall for producing another set of slots following former set of slots - Google Patents

Abstract

The method involves piercing a set of stampers (2a) through a wall of a pipe (10) for producing a set of slots (1a), and piercing another set of stampers (2b) through the pipe wall for producing another set of slots following the former set of slots, where the stampers are arranged in series. The sets of stampers are removed from the slots after making the slots, where the pipe is supported on a pipe bed (3) for making slots, and the pipe is intermittently displaced in a longitudinal direction for formation of additional slots. An independent claim is also included for a slotting tool for making slots in a pipe wall.

Description

The invention relates to a method for producing slots in a tube wall, wherein a plurality of stamps arranged in series pierces the tube wall and thereby produces the slots and a slot tool.

A manufacturing method with a plurality of in-line stamp is made of DE 4 334 203 C2 known. In this patent, there are designs with two matrices to be inserted into the tube, which together fill the tube cross-section. Using multiple dies is costly, both in tooling and in making the slots. Other versions in the cited document use only a single die, which also fills the entire pipe cross-section, which is more advantageous in itself. In the manufacture of the slots by means of a single die is provided to rotate the die after the formation of the slots from the working position to a retracted position by 180 °, so that it can be removed from the pipe again. However, realizing large Verdrehwege can adversely affect the economics of the manufacturing process, as longer cycle times may be necessary. In order to be able to realize sufficiently large collars at the slot edges, the matrix has relatively weakly formed axial connecting sections between its axially arranged support sections. (Connection sections - see in the DE'203 C2 . 7 , Reference number 4 ) It can therefore come to fractures in the die. In addition, only round tubes are shown in the publication. However, it is desirable to be able to provide tubes with as many different cross-sectional shapes as possible with the slots.

The slotting of round pipes and the use of an inner die also refers to the US 5 088 193 A , In this reference, unlike the reference described in the introduction, there are no large number of punches arranged in series. According to this publication, it is provided to first emboss impressions in the pipe wall with the aid of an arc-shaped punch corresponding to the pipe contour. In the tube is the die whose cross section is only slightly smaller than the inner tube cross section. Subsequently, the die is removed from the tube and in the impressions produced in the first step, the slots are made by means of a plug-in tool. A rotary movement of the die is not required here, since it is designed as a continuous round rod, that is, without support and connecting sections. Nevertheless, at least with regard to the economic efficiency of the production process, a disadvantage can be claimed. A disadvantage of the cited prior art is also the need to provide matrices for internal support of the pipe wall.

From the EP 1 674 170 B1 Another method and a slot tool is known. According to this method, the punches successively puncture the tube wall to create the slots. For this purpose, the slot tool slidably mounted punch and a displaceable at right angles to the stamps mounted actuator. The provision of such a slot tool can be regarded as too expensive.

In the production of slits as described above, in principle no cut-out is waste, which distinguishes these methods from other known methods in which holes are cut out and the hole edges are folded over in a flanged manner.

With the invention described below also those known methods are not addressed, in which the tube is filled with a liquid to support it for the production of the tube slots from the inside.

The object of the invention is to provide a further manufacturing method for slots in a tube wall and a slot tool, which is executable without internal support (matrix) of the tube wall.

The task solution according to the invention with a manufacturing method according to claim 1. A suitable slot tool is included in claim 5. Advantageous embodiments are contained in the subclaims.

One aspect of the production method according to the invention is that in a first step, ie in one go, a first number of punches for producing slots is pierced through the tube wall and that in a second step a second number of punches is pierced through the tube wall in the row on a slot from the first step a slot from the second step follows.

It is provided in a particularly preferred manner that the stamp from the first step remain in their slots until the second step is performed and that thereafter all the stamps are pulled out of the slots.

In addition, it is provided in a particularly preferred manner that the tube is placed in a tubular bed for carrying out the steps and supported from the outside.

It has been shown that with such a procedure, an inner support (matrix) of the pipe wall is superfluous. The production of slots succeeds with sufficient quality and accuracy.

It has been found that the retention of the punches in the slots counteracts any deformation thereof. Whether the retention of the punches in the slots is required or not depends on how high the accuracy requirements are in an individual case. However, it has also been found that the shape stiffness of the pipe wall is increased by the slots created in the first step. This increased stiffness counteracts, while maintaining certain distances of the slots, an undue deformation in the execution of the second step. Furthermore, the design of the stamp tips u. a. Influencing factors play a role here.

The slitting tool is configured so that a first number of punches can be activated for a first step and that, for a second step, the punches arranged between the punches of the first step can be activated.

The invention will be described below in an embodiment with reference to the accompanying drawings.

Brief Description

The 1 to 3 show, in a longitudinal section (x), in a longitudinal section corresponding front view (y) and in a side view (z), the initial state ( 1 ), an intermediate stage ( 2 ) after execution of the first step and a final state ( 3 ), before the withdrawal of the stamp.

The reference numerals used in the following description were predominantly in the illustrations according to 2 entered. They apply equally to the representations in the 1 and 3 ,

The pipes 10 For example, they may be made of an aluminum alloy. The production can be carried out by extrusion, by tube forming sheet metal plates and welding a longitudinal seam or by other manufacturing methods. It may, for example, be headers of a heat exchanger. The slots 1 are then receiving openings for the ends of heat exchanger tubes, which are soldered therein, for example. The cross section of the pipe 10 (Fig. Z) is approximately D-shaped in the embodiment shown, wherein the slots 1 in the flattened cross-sectional area of the tube 10 be introduced.

As from the representations ( 1 - 3 ) is apparent in the embodiment with seven punches 2 / slots 1 the first number of stamps 2a / slots 1a exactly four and the second number of stamps 2 B , which are used in the second step, is three. Both the first step and the second step are executed in a single move.

It can be concluded from the illustrations and from the previous description that a minimum of three stamps 2 is required to carry out the method, wherein in the first step, the two outer punch (first number) are used and in the second step, the intervening third punch (second number). The pipe 10 (or the slot tool) could be used to make more than three slots 1 Accordingly, as often as cyclically shifted in the longitudinal direction until the desired total number of slots 1 is manufactured (not shown).

To name an upper limit with respect to the first and second numbers does not make much sense. It will depend on many obvious circumstances. Without being limited to this, a reasonable number of punches / slots could be at a manifold 10 for an air condenser at about 20, wherein in the first step and in the second step each 10 punches 2a . 2 B would be used.

As the 2 best shows are the four stamps 2a for generating four slots 1a in the first step at the same time, ie, as mentioned, in a train, through the pipe wall 10 stung.

How then too 3 shows, in the second step, the remaining three punches 2 B at the same time through the pipe wall 10 pricked that in the row on a slot 1a from the first step a slot 1b from the second step follows. In other words, every second stamp is stamped in a single first step 2a activated in the row of stamps and in a single second step, the respectively arranged therebetween stamp 2 B ,

In the illustrated embodiment, the stamp remain 2a from the first step in their slots for so long 1a stuck until the second step is done. After that, all stamps 2a . 2 B out of the slots 1a . 1b drawn.

In the embodiment, the tube 10 to perform the steps in a tube bed 3 placed and supported from the outside. The pipe bed 3 is in two parts. It has a top 3c with corresponding passages 3e for punch guide and a lower part 3d so that in the embodiment around the entire pipe circumference an outer support is present.

Claims (6)

Method for producing slits ( 1 ) in a pipe wall ( 10 ), wherein a plurality of stamps arranged in series ( 2 ) the pipe wall ( 10 ) and punctures the slots ( 1 ), characterized in that in a first step a first number of punches ( 2a ) for generating slots ( 1a ) through the pipe wall ( 10 ) and that in a second step a second number of punches ( 2 B ) through the pipe wall ( 10 ), that in the row alternately on a slot ( 1a ) from the first step a slot ( 1b ) follows from the second step. Method according to claim 1, characterized in that the first number of punches ( 2a ) from the first step in their slots ( 1 ) remains until the second step is completed, and thereafter all dies are pulled out of the slots. Method according to one of the preceding claims, characterized in that the tube ( 10 ) for carrying out the steps in a tube bed ( 3 ) and supported from the outside. Method according to one of the preceding claims, characterized in that the tube ( 10 ) is moved clockwise in the longitudinal direction to make it with further slots ( 1a . 1b ) to provide. Slot tool for carrying out the method according to claim 1 for producing slots in a tube wall, with a plurality of serially arranged punches which pierce through the tube wall, characterized in that a first number of punches ( 2a ) is activatable for a first step and that for a second step a second number of punches ( 2 B ), one of each between the stamps ( 2a ) of the first number is arranged, can be activated. Slot tool according to claim 5, characterized in that the slot tool is a two-part pipe bed ( 3 ) to support the pipe from the outside.

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