JPS61245914A - Manufacture of pipe with thick pipe end - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing pipes with thick-walled pipe ends by cold deforming a tubular blank pipe.

BACKGROUND OF THE INVENTION Tubes of the type described above are used, for example, as torque tubes for driving automobiles. West German Patent No. 3009277
According to the specification, the central region of the tube has at least two steps, and the wall thickness of the central region is dimensioned such that all tube cross sections have the same mechanical strength. A torque tube of the type described has already been proposed.

A method of the type described at the beginning is disclosed in French Patent No. 25341.
It is described in the specification of No. 59.

The method involves cold drawing in one direction, thereby producing a hollow member with a constant outer diameter. The starting point is a reduced diameter and thickened tube end, which must subsequently be mechanically processed or bent inward by one or more presses. This method may not be able to reduce the diameter of both ends of the tube, nor may it be possible to increase the diameter.

In order to do this, a special machine must be used.

German Patent No. 30 21 481 describes a special drawing method. The process can only be carried out economically in special drawing machines in tube manufacturing plants. Although this known method makes it possible to thicken the tube wall both inwardly and outwardly at any point, the correct position of the thickened wall for the desired product also requires corresponding precision. depending on the cut to a certain size, this may require, for example, special measuring methods. This method neither increases nor decreases the diameter of the tube end.

For producing tubes with thick-walled tube ends, hot swaging and diameter reduction of the tube ends is known from EP Patent No. 2,812,803. This hot deformation not only creates scale but also creates inconvenient seams.
. The cost of implementing other such methods is significantly high.

Problems to be Solved by the Invention The object of the present invention is to provide a hollow body, particularly a torque tube used for transmitting torque in automobiles, which is suitable for lightweight construction, and which is thick at the tube end where significant stress is applied. We propose a method that can economically and dimensionally accurately cold-deform pipes with a pipe wall section that has been deformed, and that can achieve overall strengthening of the starting material by cold deformation. , that is. Furthermore, the method must be capable of being carried out on a mass-produced tube end-forming machine without the need for expensive special or separate machines.

Means for Solving the Problems The means of the present invention for solving the above-mentioned problems is to leave the thick-walled pipe ends as they are with the wall thickness of the base pipe, and to remove the central pipe section between the pipe ends. Alternatively, the tube portion adjacent to one end of the tube may be made thinner by stretching.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings schematically show an apparatus for cold deforming a tube-shaped blank tube into a tube 1. FIG. Above the center line 2 of the device are shown the components of the device and the blank tube or the tube itself in the starting position or before deformation, while below the center line 2 are shown the state after the deformation. The device and therefore also the tube after deformation is shown.

In FIG. 1, a blank pipe or tube 1 is fixed in a jaw assembly 3 of a clamping device (not shown in detail). The deforming tool 4 can be moved from the position shown above the center line 2 to the position shown below the center line 2 in the direction shown by the arrow. A calibration mandrel 5 is inserted into the interior of the deformation tool 4, and the calibration mandrel 5 is under the action of a spring 60. A stretching mandrel T can be inserted from the other side of the tube 1 and positioned opposite the calibration mandrel 5. The stretching mandrel T may already be inserted into the blank tube, but not yet in its final position.

When the deformation tool 4 is advanced over the tube end on the right side of the drawing, for example by means of a working cylinder (not shown), deformation takes place and, although limited to this deformed cylindrical area, the geometry of the outer surface of the tube end is changed by the geometry of the deformation tool. The geometry of the inner surface of the raw tube corresponds to the geometry of the calibration mandrel 5.

After this tube end diameter reduction, the tube 1 is tightened under the tension of the jaw set 3! At that time, the irregular-shaped part forming tool 8 (Fig. 2) is used to advance it in the direction indicated by the arrow over the tube end whose diameter has been reduced in Fig. 1, thereby making it irregular. A serrated notch can be formed, which is later used for transmitting torque.

It is self-evident that teeth can be provided on the inner surface of the reduced diameter tube end using a suitably configured tool.

In FIG. 6, the stretching mandrel 1 has been inserted up to the inner shoulder of the tube 1 located at the transition to the reduced diameter tube end. The arrangement consisting of the tube 1 and the drawing mandrel 7 is finally moved by clamping as a fixed stop onto the jaw set 3, which is then closed by clamping. The drawing tool 9 is moved through the tube 1 to stretch the material by a predetermined dimension, so that a thin wall is obtained in the tube section adjacent to the central tube section or the tube end, and the end of the tube 1 is stretched. The original wall thickness is maintained in this area.

In order to ensure that the tube 1 remains attached to the drawing mandrel T when the drawing tool 9 is pulled back, a counterholder 11 is arranged.

FIG. 4 shows another drawing process. In this example, the drawing is carried out in the same manner as in FIG. 6 using a separate drawing tool 12, and should be considered representative of all other possible drawing operations.

FIG. 5 shows the process of pulling out the stretching mandrel T. For this purpose, the show set 3 is slightly opened during tightening, so that the stretching mandrel 7 can be pulled back without any hindrance. At this time, the jaw set 3 acts as a separating member for the tube 1 during tightening. A prismatic receiving member 13 is arranged in the reservoir K so that the tube 1 remains within the working line. The receiving member 13 is inserted into the work line from below before pulling out the stretching mandrel T.

6 to 10 show methods and further steps for additionally deforming the second tube end. In order to deform the second tube end, the sixth tube has been rotated through 1800 revolutions and then sent again to the machine, since it is then possible to carry out the entire series of processing steps. The clamping is done using a mandrel 14 and the tube 1 is finally brought to the working position with the tube end thickening outwards.

Diameter reduction tool 15 and calibration mandrel 1 inserted into the tool
6 is used to achieve a precise reduction in the tube end diameter, matching the diameter of the central tube section reduced by stretching.
.

Instead of reducing the diameter of the second tube end as shown in FIG. 6, the diameter of the second tube end can be increased by using an increasing mandrel 17 and a spring 18, for example, as shown in FIG. 17j can also be performed by using the outer diameter sizing tool 19 which advances further.

FIG. 8 shows how another deformation tool 21 is used to further reduce the diameter of the second tube end. When using the deforming tool 4 and the calibration mandrel 5 according to FIG. 1, it is possible to reduce the diameter precisely to the same dimensions as the original tube end.

Instead of the diameter reduction according to FIG. 8 or in addition to this diameter reduction, a calibration can be carried out, for example as shown in FIG. Can be calibrated over the entire length of the stretched diameter.

FIG. 10 shows the step of forming a profile on the second tube end using the profile forming tool 8 already used for the first tube end.

11 and 12 show a step in which the tube 1 manufactured by the method steps shown in FIGS. 1 to 6 is stretched in the remaining brass section except for the right-hand reduced diameter tube end. It is shown.

As can be seen from FIG. 12, the stretching mandrel T has been slightly pulled out, and the jaw set 3 acts as a separating member when the mandrel T is slightly opened when being pulled out.

Then, tighten the stretched and reduced diameter portion of the ul to the mandrel, and increase the diameter of the thickened tube end on the right side of the tube using the inner and outer diameter dimensioning tools 23 at the same time and while calibrating.

Effects of the Invention According to the method according to the invention, a thick-walled cross-section can be provided in the starting part and a thinner-walled cross-section or other cross-section can be formed, for example by stretching and diameter reduction, i.e. without material loss and without further working. You can create the possibility. Making the pipe ends on both sides thicker, in some cases the original wall thickness is still the same, or making the other pipe end on one side thicker without carrying out the drawing diameter reduction process on the remaining pipe parts.
Stretch the entire remaining pipe section, in case.

One or both tube ends can not only have a reduced diameter, but can also be increased, if necessary, to a larger outer diameter compared to the outer diameter of the thin-walled tube section. By means of the method according to the invention, significant cost savings are obtained simply due to material savings when producing tubes with thick-walled tube ends, which can also be stretched by the use of conventional tube-forming machines. A significant increase in strength is also obtained in the area deformed at the ends.

The present invention makes it possible to manufacture workpieces of a wide variety of shapes with high dimensional accuracy starting from a material in the shape of a simple hollow body, and moreover, it is possible to manufacture workpieces of a wide variety of shapes with high dimensional accuracy, and furthermore, with the material pipe properly and accurately determined in advance, other shapes can be produced. It is possible to omit the processing of If necessary, the excess material due to the widening of the blank can simply be cut off at the end face.

[Brief explanation of the drawing]

Figure 1 shows the process of reducing the diameter of the end of the 10th pipe, Figure 2 shows the process of creating an irregularly shaped part at the end of the 10th pipe, and Figure 6 shows the process of manufacturing the thin-walled pipe section in the center. Figure 4 shows the first drawing process for , further reducing the diameter of the central thin-walled tube section.
Figure 5 is a diagram showing the configuration of the 10th pipe end after finishing; Figure 6 is a diagram showing the process of reducing the diameter of the 20th pipe end; Figure 7 shows increasing the diameter of the 20th tube end.
A diagram showing the process, FIG. 8 is a diagram showing the process of further reducing the diameter of the 20th tube end, FIG. 9 is a diagram showing the process of calibrating the tube,
FIG. 10 is a diagram showing the process of forming a deformed portion at the 20th tube end, and FIGS. 11 and 12 are diagrams showing the process of increasing the diameter of the tube end whose diameter was previously reduced. 1... Pipe, 2... Center line, 3... Jaw assembly for tightening, 4... Deformation tool, 5... Calibration mandrel, 6...
・Spring, T... Stretching mandrel, 8... Irregular part forming tool, 9... Stretching tool, 11... Opposing holder, 12
... Extension tool, 13... Receiving member, 14... Mandrel for tightening, 15... Diameter reducing tool, 16... Calibration mandrel, 17... Diameter increasing mandrel, 18... Spring , 19...Outer diameter dimensioning tool, 21...Deformation tool,
22... Calibration tool, 23... Inner diameter/outer diameter dimensioning tool.

Claims (1)

[Claims] 1. In a method for manufacturing a pipe having a thick-walled pipe end by cold deforming a tubular raw pipe, the thick-walled pipe end is adjusted to the wall thickness dimension of the raw pipe. 1. A method for manufacturing a tube with thick-walled tube ends, characterized in that the tube ends are left as they are, and the tube section in the center between the tube ends or the tube section adjacent to the tube ends is made thinner by stretching. 2. Starting from the raw pipe, first reduce the inner diameter and outer diameter of one thick-walled pipe end, then reduce the outer diameter of the central or thin-walled pipe portion adjacent to the pipe end in one step or in multiple steps. 2. The method according to claim 1, wherein the diameter is reduced by stretching. 3. First, the diameter of the reduced pipe end is increased again after stretching,
3. The method according to claim 1, wherein the outer diameter is greater than the outer diameter of the thin-walled tube section. 4. The method according to any one of claims 1 to 3, wherein the diameter of the remaining thick-walled tube end is reduced to have the outer diameter of the thin-walled tube section. 5. A method according to any one of claims 1 to 3, in which the diameter of another thick-walled tube end is increased to have a larger outer diameter than the thin-walled tube section. 6. The method according to any one of claims 1 to 4, wherein the inner diameter and outer diameter of another thick-walled tube end are reduced. 7. Claim 1, which calibrates the entire length of the tube
The method described in any one of paragraphs 6 to 6. 8. The method according to any one of claims 1 to 7, wherein a deformed portion is formed on the inner and/or outer surface of a thick-walled tube end.