EP0788849B1 - Method of manufacturing a pipe with sections of differing wall thickness and a pipe with sections of differing wall thicknesses - Google Patents

Description

The invention relates to the use of tubes with sections different wall thickness for the production of Body parts or chassis components.

DE 33 43 709 A1 includes a molding method of frame parts for motor vehicles to the state of Technology in which a metal sheet is initially rolled like this is that parallel depressions are formed. This different wall thicknesses should result from that the roller has differently sized sections Has.

The rolled metal sheet is then cut to size and bent the individual pieces lengthways. On in this way frame parts can be created which in Cross section have different wall thicknesses, however Seen across the length, the cross-sections are always the same exhibit. It is not possible in the longitudinal direction of the frame parts partially reduced in wall thickness Create areas to meet the respective local voltage spikes to take targeted account. This is what it aims at however, the invention.

From EP-A-0 620 056 a tube is known with in Axial direction different wall thicknesses, which as Structural component is used. The manufacture of the Pipe is made up of different pipe sections Inner diameter that are welded together. This is associated with a high manufacturing effort. In addition, the radial welds in the transition areas between the different thicknesses Pipe sections represent potential weak points.

The invention is based on the prior art Task based on the production of body parts or chassis components, which are seen along their length exposed to different loads, in material and weight-saving design more economical shape.

The object is achieved by the use a pipe with different wall thicknesses in the longitudinal direction having sections for the production of body parts or chassis components of motor vehicles solved, in which first a targeted rolling Deformation of the starting sheet with areas in the rolling direction changing sheet thicknesses have been made is. The rolled sheet is then made to meet requirements circumcised. The resulting intermediate product is then formed into a tube and joined along the edges connected.

The tube used has sections in the longitudinal axis direction different wall thickness. This in some areas Reduced wall thickness tube is used for the production of Used components that are under external stress, in which, however, the tensions occurring due to the Component construction distributed over the component in different Height. Examples of so different heavily loaded components are body parts or chassis components of motor vehicles. Will the Components dimensioned according to the maximum load, led so far not only for an unnecessary use of materials, but above all at an unnecessary weight. This Disadvantages are avoided according to the invention in that the pipes used to manufacture the components according to the subsequent load in the individual Areas of the components dimensioned differently are. With this one becomes the expected later Can handle loads and can also use material and thus save weight.

A metal sheet is expediently used as the starting material used with one of the greatest wall thickness of the manufacturing pipe corresponding thickness. Of course but can also the starting material with a corresponding Excess are provided. Advantageous the starting material is withdrawn from a coil and for further processing in rolling technology.

Coordinated with the later use of the pipes manufactured A targeted partial wall thickness reduction then takes place by rolling. In this context it allows the invention, the rolling direction of each Adjust configurations of the later pipe. You can the output sheets twice or possibly several times in partially rolled in different directions. Thereby can the respective thickness according to the requirements can also be varied step by step. Various Ironing rates and different transition areas between the thicker and thinner areas are possible.

The transitions from one sheet thickness range to another can be stepless or stepped.

Rolling can take place in a two-roll stand. By Variation of the roller geometry in the roller inlet can Symmetry with respect to the median transverse plane in predeterminable Limits are affected.

The specifically deformed sheet has deliberately varied ones Cross sections on to diverse according to the application Areas to convey precisely those wall thicknesses which depends on the respective loads and thus also the locally differing voltage peaks are who these areas in practical use get abandoned.

Following the rolling deformation, this will be Sheet cut to size around the longitudinal axis Formed tube and joined along the joints. This is usually done by welding of bumps. Different methods are available for this Available, for example laser, inert gas, inductive or resistance welding.

Because with the ironing process both symmetrical and highly asymmetrical geometries can be created it is recommended that those with the less highly educated Paragraphed side or the almost smooth trained side to lay on the outside of the tube.

The rolled sheet can be processed before further processing in parallel to the rolling direction Metal strips are divided. This way from a large output board several tubes of the same Establish configuration.

Forming the sheets or strips into tubes can be done in a rolling mill. A another advantageous embodiment provides from the rolled sheets in a die first a semi-circular profile to emboss and then in another Embossing step to finish the tube.

If necessary, a pipe can be divided into shorter ones Length sections are made.

Figur 1

in perspektivischer Darstellungsweise ein abgestrecktes Blech mit bereichsweise unterschiedlichen Blechdicken;

Figur 2

ein Blech gemäß der Figur 1 in der Draufsicht;

Figur 3

eine weitere Ausführungsform eines Blechs in der Seitenansicht und

Figur 4

den Umformvorgang einer Platine zu einem Rohr in drei Teildarstellungen.

The invention is described below with reference to the drawings. Show it:

Figure 1

in perspective, a stretched sheet with different sheet thicknesses in some areas;

Figure 2

a sheet according to Figure 1 in plan view;

Figure 3

a further embodiment of a sheet in the side view and

Figure 4

the forming process of a blank into a tube in three partial representations.

FIG. 1 shows a section of a sheet 1 in which areas 2-5 have been ironed out by a targeted rolling deformation with sheet thicknesses s ₂ to s _{5 that} change in the rolling direction WR.

In the transition areas 6, 7 and 8 the areas go 2-5 each by an incline 9, 10, 11 almost continuously into each other.

On the underside 12, the sheet 1 has approximately one smooth surface 13. Figure 2 shows a sheet 1 in plan view. In which deformed sheet 1, the areas 2-5 have such Wall thicknesses that are matched to the respective Loads and voltage peaks, which one from the sheet 1 manufactured tube is subject to or resulting from it result in practical use as a construction component.

FIG. 3 shows a sheet 14 which has an asymmetrical geometry, based on its central transverse plane MQ, with areas 15-18 of different sheet thicknesses s ₁₅ -s _16. Both the top 19 and the bottom 20 of the sheet 14 vary accordingly in steps in different ironing rates.

Since the surface 19 has the larger gradations, the forming of the sheet 14 into a tube is expedient made so that the top 19 the inside of the tube and the bottom 20 the outside of the Tube.

The manufacture of a tube from a plate 21 is based on of Figure 4 technically generalized.

In this way, pipes can be used economically and with manufacture with high accuracy. Before forming into a pipe is the initially flat board in some areas Rolling wall thickness reduced and then accordingly been circumcised. The different dimensions the wall thickness is based on the subsequent load of the processed pipe matched in practical operation.

The board 21 is placed in a die 22 (FIG 4, above) and charged by a stamp 23 like this is indicated by the arrow F. The board 21 forced into the die form 24 and a semicircular profile 25 coined (Figure 4, middle).

The next step is to form a tube 26 in the die form 24 with the help of the stamp 27, the a configuration corresponding to the tube 26 with a counter shape 28 (Figure 4, below).

Subsequently, the abutting edges 29, 30 by means of automatic laser welding with seam detection and - added tracking.

The tube 26 thus finished then stands for the other Processing available. It points in the axial direction with different wall thicknesses. This configuration is precisely tailored for later use of the pipe and the loads and Voltages to which the tube 26 is then subject.

Claims (1)

1. Use of a tube (26) with portions which have different wall thicknesses in the direction of the length, for making bodywork parts or chassis components of motor vehicles, wherein an initially flat metal sheet is first subjected to a rolling deformation, with sheet thicknesses (s₁-s₅; s₁₅-s₁₈) varying in zones in the rolling direction (WR), said rolling deformation being adapted controllably to the loads distributed at different levels over the length of the subsequent bodywork parts or chassis components, the rolled metal sheet (1, 14) is then cut to size, then shaped into the tube (26) and finally joined along the abutting edges.

Images