JP2007509795A - Method of manufacturing pivot beam torsion beam axle and cross member - Google Patents

Abstract

  The present invention relates to a pivot beam torsion beam axle for an automobile, the pivot beam torsion beam axle having two trailing arms (2, 3) joined by a cross member (4). And a method for producing a cross member (4). This cross member consists of a hollow profile having a central section (5) that is partially open. The central section (5) has an elongated opening (8), and the edge region of the opening is at least partially provided with a web (11). Connected to the central section (5) is a tubularly closed end (6, 7). The web (11) is curved in an arcuate shape, and the opening between the tangent that touches the outer periphery of the central section (5) and the tangent that touches the end of the web is preferably between 5 ° and 90 °, preferably 15 ° to 70 °.

Description

  The present invention relates to a pivot beam torsion beam axle for an automobile and a method of making a cross member for a pivot beam torsion beam axle.

  A pivot beam torsion beam axle, which is a composite trailing arm axle, is superior in that it is easily configured according to the vehicle characteristics when the required space is small and the operation characteristics are good. The cross member that joins both side trailing arms acts as a torsion profile, resulting in trailing arm characteristics when disengaged simultaneously, and semi-trailing arm characteristics when disengaging alternately. Occurs.

  From German Offenlegungsschrift 19949341 a pivot beam torsion beam axle for a motor vehicle is known which has two trailing arms connected by a cross member. In this case, the cross member consists of a hollow profile having a central section that is partially opened, which is followed by tubular ends on both sides.

  German Offenlegungsschrift 10122998 discloses a similar concept. The cross member is formed in a tubular shape and has an opening extending in an elliptical shape in the central section.

  The prior art also includes a vehicle axle according to German Patent No. 19533479. The cross member of the axle has a notch that extends axially with respect to the longitudinal axis of the tube, in which case the notch is at least partly in the edge region, the tube It is surrounded by a web constructed inside. These webs are folded significantly inwardly, and in this case it is desirable that the height of the web substantially corresponds to the width of the notches in the tube.

  With the configuration described above for the pivot beam torsion beam axle, a design of the moment of resistance tailored to the dynamic load can be achieved. The principal stresses that occur during travel are concentrated in the transition region between the end and the open central section, i.e. in the free torsion length behind the connection region with the trailing arm. This can impair the service life of the cross member and thus the entire pivot beam torsion beam axle when a torsion load is applied.

  In order to produce a cross member of a pivot beam type torsion beam axle, a blank corresponding to the developed view is punched out. These blanks are then correspondingly deformed into a tube and joined along the longitudinal edges adjacent to each other. Actually, it has been found that a microcrack is easily formed in the direction of the thin plate due to the blank cut portion on the surface of the cut edge. This leads to an increased risk of cracking, which can lead to a significant decrease in the service life of the axle when in use when loaded by the acting gravity. This is particularly confirmed when the production tool has been used for a long time and the cutting gap of the punch or cutting tool has expanded and reached an acceptable limit. The result is a hidden danger with respect to the service life loss due to degraded cutting edge conditions.

  The high and non-uniform return force applied to the cut profile during profile molding can result in shape inaccuracy, which ultimately results in the pivot beam torsion beam axle. Unevenness of torsional stiffness characteristics (Rollsteifigkeitsverhalten) can occur.

  Therefore, the problem underlying the present invention is that, starting from the prior art, the known construction type pivot beam torsion beam axle is improved with respect to the service life at a high dynamic possible output, and is optimized in terms of use technology. It is to provide a method for producing a cross member.

  According to the present invention, a means for solving the problem is a pivot beam type torsion beam axle having the features of claim 1.

  A cross member connecting both trailing arms is formed in the form of a hollow profile having a partially open central section, which has a long extending opening, The edge region of the part is at least partially provided with a web. The end of the cross member is closed in a tubular shape.

  Means that the web is curved in the shape of an arc, and in this case the opening between the tangent that is in contact with the outer periphery of the central section and the tangent that is in contact with the end of the web is between 5 ° and 90 °. The core of the. By this means, i.e. the integral molding of the arcuately curved web, the open cross-section is placed directly outside the region of action of the shear force along the edge of the cut-out region. This results in a significant improvement in the dynamic load capacity of the cross member. The negative impact of blank profile variations is significantly reduced. As a whole, the service life of the cross member, and consequently the service life of the pivot beam torsion beam axle can be improved. Furthermore, the process of transforming the cut blank into a finished pipe profile is improved. This is because the return force is significantly reduced by the molded web or webs. This provides improved molding tolerances for the profile.

  As described in claim 2, the opening is particularly preferably between 15 ° and 70 °. The radius of curvature of the arc curved web is adjusted according to the strength of each sheet.

  Depending on the vehicle type and the configuration of the pivot beam torsion beam axle adapted to the required operating parameters, the web is oriented inwardly with respect to the longitudinal axis of the cross member (Claim 3) or outwardly. May be directed (claim 4).

  According to the features of claim 5, the web extends tubularly over the entire length of the opening. This configuration is advantageous in practice especially in the heavy configuration of a pivot beam torsion beam axle.

  Basically, the web according to claim 6 may extend only in the transition region from the central section to the end. In other words, the cut edges of the openings may merge and extend only into the region where the cross member moves to a closed tube profile. Here, the main stress generated during running is concentrated. These stresses can be compensated in these areas by the integrally formed web according to the invention.

  In practice, a particularly elliptical contour of the opening is provided in the central section as claimed in claim 7.

  The solution of the method part of the problem is in the method of claim 8.

  In order to produce a cross member, first, a blank corresponding to the geometry of the developed view of the cross member is produced. This blank basically has a rectangular configuration, and in this case, when the blank is cut, a concave opening is formed on the side in the longitudinal direction. The edges of these openings are folded in an arc at an additional molding stage or directly when cutting the blank. The blank is then rolled into a tube as is known and then joined along the adjacent longitudinal edges of the end of the cross member. This is preferably done by welding.

  Fabrication of the cross member is reasonable and can be automated very well. As already mentioned above, the shaping of the cut blank into a finished tube profile is improved. This is because the return force is significantly reduced by the molded web, which contributes to better profile accuracy.

  Embodiments of the invention will now be described in detail with reference to the drawings.

  FIG. 1 shows a perspective view of a pivot beam torsion beam axle 1. The pivot beam type torsion beam axle 1 mainly includes trailing arms 2 and 3 for guiding two wheels, and a cross member 4 for connecting both of the trailing arms 2 and 3. This cross member 4 consists of a single hollow profile, which is provided with a central section 5 that is partially open, each of which is tubularly closed on both sides. Ends 6 and 7 are connected.

  The geometry of the cross member 4 is adjusted to the load expected to be applied to the pivot beam torsion beam axle 1 in the automobile.

  The central section 5 has an elliptical elongated opening 8. This results in an open cross section in the central section 5 having a circular sector shape, an elliptical shape or a V-shaped or U-shaped configuration. The leg length of the central section 5, measured over the circumference as seen in the cross-sectional view, decreases from the ends 6, 7 towards the center of the cross member. In the trailing arms 2 and 3, suitable accommodating portions 9 and 10 for the end portions 6 and 7 of the cross member 4 are formed. End portions 6 and 7 are fitted in the housing portions 9 and 10 and are joined and, in principle, welded. Thereby, good force transmission from the trailing arms 2 and 3 to the cross member 4 is guaranteed.

  The opening 8 has at least partly a web 11, 12 or 13 in the edge region (for this, see FIGS. 2, 3 and 4). These webs 11, 12, and 13 are curved in an arcuate shape. 2 and 4, the web 11 or 13 is directed inwardly with respect to the longitudinal axis L of the cross member 4, whereas the cross member 4 having the configuration according to FIG. 12 is directed outward with respect to the longitudinal axis L of the cross member 4.

  The curvature of the web 11, 12 or 13 is basically selected as follows: a tangent T1, T2 or T3 in contact with the outer periphery U of the central section 5 and an end 14 of the web 11, 12 or 13 , 15 and 16 are selected such that the opening α, β or γ between tangents T4, T5 and T6 is between 5 ° and 90 °, preferably between 15 ° and 70 °. Has been.

  In the configuration shown in FIG. 2, the opening α of the cross member 4 is specifically about 66 °. For a horizontal plane HE extending through the opening 8 or generally the cross member 4, the angle δ is 48 °.

  In the configuration of the cross member 4 according to FIG. 3, the opening β is 50 °. For the horizontal plane HE intersecting the cross member 4, an angle ε of 32 ° is produced.

  The opening γ of the cross member 4 according to FIG. 4 is 36 °. As a result, the angle η of the tangent T6 of the end 16 or the web 13 is 16 ° with respect to the horizontal plane HE.

  The arcuately curved web 11, 12 or 13 indicates that the open cut surface is shifted along the end 14, 15 or 16 from the normal profile extension of the hollow profile of the cross member 4. Bring. Negative effects that can occur from the blank section, such as microcracks, are thus displaced from the main stress and main force transmission path. When the dynamic possible output of the pivot beam torsion beam axle 1 is high, such a relatively simple means contributes significantly to the improvement of the service life.

  As can be seen from FIG. 1, the web 11 extends over the entire length of the opening 8. It is also possible for the web 11, 12 or 13 to be provided only in the transition region from the central section 5 to the ends 6, 7.

  In order to produce the cross member 4, a blank 17 made of metal, for example steel, aluminum or another metal material is prepared. The blank 17 has a thin plate section, and the circumferential geometry of the thin plate section corresponds to the developed view of the cross member 4. The basic configuration of the developed view is a rectangle, and in this case, a concave opening 19 is punched in the longitudinal direction side portion 18 of the blank 17. This configuration can be seen in FIG. In a separate deformation step, the edge 20 of the opening is folded in an arc with respect to the plane of the blank 17, as can be seen by way of example in FIGS. 5b and 5c. The cut blank 17 is then deformed into a tubular shape and the longitudinal edges 21, 22 adjacent to each other at the ends 6, 7 are welded together. In this case, the ends 6, 7 have a closed circular cross section.

1 is a perspective view of a pivot beam torsion beam axle according to the present invention. FIG. 5 is a vertical cross-sectional view of the central section of the first configuration of the cross member. FIG. 6 is a vertical cross-sectional view of the central section of the second configuration of the cross member. FIG. 6 is a cross-sectional view showing an edge region of an opening having an arcuately curved web. It is an expanded view of the blank of a cross member. 5b is a cross-sectional view showing a first variant embodiment of the edge region of the central lateral plane of the blank according to FIG. 5a. 5b is a cross-sectional view showing a second variant embodiment of the edge region of the central lateral plane of the blank according to FIG. 5a.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Pivot beam type torsion beam axle, 2, 3 Trailing arm, 4 Cross member, 5 Center section, 6, 7 4 End, 8 Opening part, 9,10 accommodating part, 11, 12, 13 Web, 14 11 End, 15 12 end, 16 13 end, 17 blank, 18 longitudinal side, 19 opening, 20 edge, 21, 22 longitudinal edge, L longitudinal axis, U outer circumference, T1, T2, T3, T4, T5, T6 tangent, HE horizontal plane, α, β, γ opening, δ, ε, η angle

Claims (8)

  A pivot beam torsion beam axle for an automobile, the pivot beam torsion beam axle having two trailing arms (2, 3) joined by a cross member (4), the cross member (4 ) Is made of a hollow profile having a central section (5) that is partially open, and an elongated opening (8) is provided in the central section (5), the opening (8 ) At least partly in the edge region, and in the form of a tube-shaped end (6, 7) connected to the central section (5) The web (11, 12, 13) is curved in an arcuate shape, the tangent line (T1, T2, T3) contacting the outer periphery (U) of the central section (5), and the web (11, 12, 13). ) End (14, 5, 16) Pivot for an automobile, characterized in that the opening (α, β, γ) between tangents (T4, T5, T6) tangent to 5 and 16) is between 5 ° and 90 ° Beam type torsion beam axle.   The pivot beam type torsion beam axle according to claim 1, wherein the opening degree (α, β, γ) is between 15 ° and 70 °.   Pivot beam torsion beam axle according to claim 1 or 2, wherein the web (11, 13) is oriented inwardly with respect to the longitudinal axis (2) of the cross member (4).   Pivot beam torsion beam axle according to claim 1 or 2, wherein the web (12) is oriented outwardly with respect to the longitudinal axis (2) of the cross member (4).   5. A pivot beam torsion beam axle according to any one of claims 1 to 4, wherein the web (11, 12, 13) extends over the entire length of the opening (8).   5. The pivot beam torsion beam according to claim 1, wherein the web (11, 12, 13) extends into a transition region from the central section (5) to the end (6, 7). Axle.   7. A pivot beam torsion beam axle according to any one of claims 1 to 6, wherein the opening (8) extends in an elliptical shape.   8. A method for producing a cross member (4) for a pivot beam torsion beam axle according to claim 1, wherein a flat blank (1) corresponding to the geometry of the development of the cross member (4). 17), a concave opening (19) is provided on the longitudinal side (18) of the blank (17), after which the edge (20) of the opening (19) is placed on the plane of the blank Cross member (4) for a pivot beam torsion beam axle, characterized in that it is bent in an arcuate shape and then the blank is deformed into a tube and joined along the longitudinal edges (21, 22) adjacent to each other. ).

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