FR2776543A1 - Forming motor vehicle suspension wishbone - Google Patents

Abstract

The method of forming a suspension wishbone (1) involves punching a hole (2) in the sheet wishbone and pressing the edge of the hole to form a cylindrical seating (3) for a suspension joint. As the hole is punched, two projections (4) are formed to define a clip to retain the joint.

Description

I The invention relates to a method for producing at least one

  hinge housing of a metallic suspension triangle, to the suspension triangle obtained by the process

  as well as a punch for implementing the process.

  i The invention relates more particularly to the production, in a suspension triangle, of housings in which

  are fitted or clipped elastic joints.

  To form the housings of the elastic joints clipped into a suspension triangle, it is known to I (make circular holes or "pre-holes" in the metal sheet constituting the triangle. As shown in FIG. 2, the areas of triangle 1 which are peripheral to the holes 2 are then stamped by means of a punch 7, to

form a cylindrical housing.

  However, according to this method, the edge 8 (FIG. 4) constituting the free end of the housing 3 of the joint has a poor surface condition which can damage the elastic joint 3 by shearing. Furthermore, one does not obtain a good parallelism of the edge 8 of the end of the housing 3 relative to the plane of the triangle. This results in improper positioning and improper fixation of the joint in

his accommodation.

  It is also known to produce the articulation housings by double punching, that is to say that the punch 7 (FIG. 3) comprises a blade 9 cutting before forming the housing 3. According to this technique, the edge 8 constituting the free end of the housing 3 has a better surface condition, but its parallelism with the plane of the triangle 1 is still unsatisfactory. Furthermore, during the 3 cutting with the punch 7, a circular chip is formed on

  the tool that is difficult to remove.

  An object of the present invention is to provide a method for producing, in a metal suspension triangle, at least one fitting or clipped joint housing, overcoming all or part of the drawbacks of the art

previously noted above.

  This object is achieved by the fact that in the production method according to the invention, in a metal suspension triangle, of at least one fitting or clipped articulation housing consisting of: punching at least one hole in a metal sheet constituting the triangle, then to stamp the peripheral zone of each hole, to form a substantially cylindrical articulation housing, the punching of the 1 <) holes is carried out so that the contour of each hole is substantially circular and comprises at least two projections material oriented towards the center of the hole, the projections being shaped to form, after the stamping step, the support and clip areas of one of the ends of the joint, these support areas being located in a plan

parallel to the plane of the triangle.

  According to another particular feature, the stamping of the peripheral zone of the holes is carried out by a simple punching operation of the metal sheet constituting the

triangle.

  According to another particular feature, the stamping of the peripheral zone of the holes is carried out by a step of pre-cutting a small portion of the end of the projections, followed by at least a first punching step intended

to form the accommodation.

  According to another particular feature, the first punching step forms a housing the dimensions of which are very slightly smaller than the dimensions required for the joint, this first punching step being followed by a step of scraping the internal surface of the

  housing (3) by means of a punch.

  According to another particularity, between the first punching step and the scraping step, a second punching step of the housing is carried out, consisting in forming, on the surface defining the housing and in a direction perpendicular to the plane of the triangle, at least a groove, to avoid the formation of a circular chip on the punch

during the scraping step.

  z According to another particularity, the holes have three projections arranged at 120 degrees from one another relative to the

center of the hole.

  According to another particular feature, the projections are located in the plane of the metal sheet constituting the triangle and each have substantially the shape of a quadrilateral, the edges of the projections located opposite the center of the hole being located.

  on the same fictitious circle which is concentric with the hole.

  According to another particular feature, the precut step, the first punching step, the second step of l. punching and scraping step are carried out by a

same punch.

  Another object of the present invention is to provide a

  suspension triangle obtained by the process.

  This object is achieved by the fact that in the triangle of 2) suspension obtained by the method, the edge constituting the free end of the housings of the clipped joints comprises at least two lugs or projections constituting the points of support and clipping for a of the ends of the joint, these support points being located in a plane

  substantially parallel to the plane of the triangle.

  Another object of the present invention is to provide a punch specially designed for the implementation of the method. This object is achieved by the fact that the punch for implementing the method comprises precut means, first punching means intended to form the housing, second punching means forming at least one groove on the surface defining the housing. and

means for scraping this surface.

  Other characteristics and advantages of the invention

  will appear on reading the detailed description which will

  follow, for the understanding of which reference will be made to the appended drawings, in which - Figure 1 shows a sectional view of a suspension triangle of the prior art illustrating the two elastic joints clipped into respective housings formed in the triangle, - Figures 2 and 3 show respectively, and schematically, two embodiments of the articulation housings of the suspension triangle according to the prior art, - Figure 4 shows a sectional view of a housing articulation of a suspension triangle produced according to the prior art, - FIGS. 5, 6, 7A, 7B, 8A, 8B, 9A, and 9B schematically represent the succession of steps in the process for producing articulation housings according to the invention, - Figure 10 schematically shows the profile of a punch specially designed for the implementation of the

method according to the invention.

  The invention will now be described with reference to Figures 1, 5, 6, 7A, 7B, 8A, 8B, 9A and 9B. Figures 7A, 8A and 9A show a top view of a part of the metal sheet constituting the suspension triangle. Figures 7B, 8B and 9B respectively show sectional views

Figures 7A, 8A and 9A.

  Figure 1 shows a sectional view of a triangle 1 of suspension of the prior art, illustrating the two elastic joints clipped into respective housings

of triangle 1.

  To make the housing for joints 5 clipped to the triangle 1 of metal suspension, one begins by making holes 2 in the metal sheet constituting the triangle 1 at the locations provided for the joints 5. These holes 2

  are made by punching or any other equivalent means.

  According to the invention, each hole 2 is made so as to have a substantially circular shape and defining at least two

  îo projections 4 of material oriented towards the center of the hole 2.

  In the nonlimiting example of FIG. 5, the hole 2 defines three lugs or projections 4 located in the plane of the triangle 1 of suspension. The projections 4 are arranged at 120

  degrees from each other from the center of hole 2.

  Each of the projections 4 has substantially the shape of a trapezium, the large base of which is secured to the edge of the hole 2 and the small base, which is opposite the center of the hole 2, will constitute a

support area for the joint 5.

  The portions of the triangle 1 peripheral to the holes 2 are then stamped to form housings 3 of substantially cylindrical articulation. The holes 2 are shaped so that, after the stamping step, the ends 44 of the projections 4 are located in the same plane which is parallel to the plane of the triangle 1 (FIG. 7B). That is to say that the edges of the projections 4 located opposite the center of the hole 2 are curved and located on the same fictitious circle which is concentric with the hole 2. The edges constituting the ends 44 of the three projections 4 constitute the three points of support and

  clip one end of the joint 5.

  (Obviously, it is possible to provide alternative embodiments in which the holes 2 comprise two or

more than three projections 4.

  The positioning of the joints in the triangle is improved compared to the prior art because the parallelism of the plane containing the three support points 44 (projections 4) by

  relation to the plane of triangle 1 is well under control.

  The stamping of the peripheral zone of the holes 2 begins according to the invention with a step of pre-cutting the end of the projections 4. The small portion of the ends of the projections 4 which are pre-cut are shown schematically in lines

bold in Figure 6.

  This precut step, which is optional, is intended to ensure a good surface condition at the ends 44 of the projections 4 which will constitute the bearing zones for

the joint 5.

  The portions of the triangle 1 peripheral to the holes 2 are then punched (Figures 7A and 7B), to form

3 cylindrical housings.

  This first punching step is carried out so as to form a housing 3 whose dimensions are very slightly smaller than the dimensions required for the joint 5, this in anticipation of a scraping step described below. In other words, the diameter of the cylindrical housing 3 2) obtained after this first punching is less than a few tenths of a millimeter compared to the diameter required for the joint 5, for example less than

0.2 mm.

  This first punching step is followed by a second punching step (FIGS. 8A and 8B) of the housing 3 which consists in forming, on the surface defining the housing 3, at least one groove 15. In the example shown in FIGS. 8A and 8B, two grooves 15 are formed in a direction perpendicular to the plane of the triangle 1, the two grooves 15 being diametrically opposite with respect to the center of the housing 3. These grooves 15 are formed in the tubular wall constituting the housing 3 by deformation of the sheet metal using a punch 6 or any other equivalent means. The grooves 15 are provided to prevent the formation of a circular chip on the punch 6 which

  will scrape the interior surface of the housing 3.

  Furthermore, these grooves 15 advantageously increase the

  rigidity of the cylinder constituting the hinge housing 3.

  Thus, as mentioned above, the second punching is followed by a scraping of the internal surface of the housing to bring the cylindrical housing 3 to the required diameter and to ensure it a good surface condition. The figures

  9A and 9B show diagrammatically the surfaces scraped by bold lines.

  I (Due to the grooves 15, no circular chip is created which would get stuck on the tool which performs the scraping. In fact, the two grooves 15 have the effect of delimiting two separate chips on the tool, more easy to

  remove only one circular chip.

  IF Advantageously, the pre-cutting step, the first punching step, the second punching step and the scraping step can be carried out by a single tool, that is to say the same punch 6 performing a

single pass.

  To this end, the single punch 6 according to the invention, the profile of which is shown diagrammatically in FIG. 10, comprises means 11 for precutting, first punching means 12 intended to form the housing 3, second 13 punching means forming the grooves 15 and scraping means 14. The means 11 for precutting and the scraping means 14 consist of two respective blades formed on the periphery of the punch 6. The second 13 punching means consist of two bosses 13

  diametrically opposed on the periphery of the tool 6.

  Of course, the invention cannot be limited to the exemplary embodiment described above. Thus, the precut step described above can be optional. That is to say that if a poor surface condition can be tolerated at the level of the support zones formed by the projections 4, the stamping of the housings 3 can be carried out by a simple punching operation of the sheet. metallic. Likewise, the second punching step which forms grooves 15 before scraping can be optional if the difficulties of removing the circular chip stuck in the scraping means are tolerated. The scraping step can also be omitted, if, for example, it is not necessary to have a good surface condition inside the housing 3. It is also possible to provide that the second punching step does not forms an I (only one or more than two grooves 15 which divide the circular chip. Although the invention has been described in connection with particular embodiments, it comprises all the

  technical equivalents of the means described.

  Finally, the marks inserted after the characteristics

  techniques set out in the claims are for the sole purpose

  to facilitate understanding of these and cannot

limit its scope.

Claims (10)

CLAIMS R E V E N D I C A T I O N S   1. Method for producing, in a triangle (1) of metal suspension, at least one housing (3) of articulation (5) fitted or clipped consisting of: - punching at least one hole (2) in a metal sheet constituting the triangle (1), then to - stamp the peripheral zone of each hole (2), to form a housing (3) of substantially cylindrical articulation, characterized in that the punching of the holes (2) is io carried out so that the outline of each hole (2) is substantially circular and comprises at least two projections (4) of material oriented towards the center of the hole (2), the projections (4) being shaped to constitute, after the stamping step , the support zones (44) and clip-on of one of the ends of the articulation (5), these support zones (44) being   located in a plane parallel to the plane of the triangle (1).   2. A method of making, in a triangle (1) of metal suspension, at least one housing (3) of articulation (5) fitted or clipped according to claim 1, characterized in that the stamping of the peripheral zone holes (2) is made by a simple punching operation of the   metallic sheet constituting the triangle (1).   3. A method of making, in a triangle (1) of metal suspension, at least one housing (3) of articulation (5) fitted or clipped according to claim 1, characterized in that the stamping of the peripheral zone holes (2) is produced by a step of pre-cutting a small portion of the end of the projections (4), followed by at least a first   punching step intended to form the housing (3).   3 () 4. Method for producing, in a triangle (1) of metal suspension, at least one housing (3) of articulation (5) fitted or clipped according to claim 3, characterized in that the first punching step forms a housing (3) whose dimensions are very slightly smaller than the dimensions required for the articulation (5), this first punching step being followed by a scraping step of   the internal surface of the housing (3) by means of a punch (6).   5. Method for producing, in a triangle (1) of metal suspension, at least one housing (3) of articulation (5) fitted or clipped according to claim 4, characterized in Io that between the first step of punching and the scraping step, a second punching step of the housing (3) is carried out, consisting in forming, on the surface defining the housing (3) and in a direction perpendicular to the plane of the triangle (1), groove, to avoid the formation of a circular chip on the punch (6) during the scraping step. 6. Method for producing, in a triangle (1) of metal suspension, at least one housing (3) for articulation (5) fitted or clipped according to any one of   21 (claims 1 to 5, characterized in that the holes (2)   have three projections (4) arranged at 120 degrees, one of   the other relative to the center of the hole (2).   7. Method for producing, in a triangle (1) of metal suspension, at least one housing (3) for articulation (5) 2 'fitted or clipped according to any one of   Claims 1 to 6, characterized in that the projections (4) are   located in the plane of the metal sheet constituting the triangle (1) and each have substantially the shape of a quadrilateral, the edges of the projections (4) located opposite the 3.) center of the hole (2) being located on the same fictitious circle which is concentric with the hole (2).   8. A method of making, in a triangle (1) of metal suspension, at least one housing (3) of articulation (5) fitted or clipped according to claim 5, characterized in that, the precut step, the first stage of punching it, the second stage of punching and the stage of   scraping are carried out by the same punch (6).   9. Suspension triangle (1) obtained by the process according to any one of Claims 1 to 8, characterized in that   that the edge constituting the free end of the housings (3) of the clipped articulations (5) comprises at least two lugs (4) or   projections constituting the support and clipping points for one of the ends of the articulation (5), these support points being located in a plane substantially parallel to the plane of the triangle10 (1).   10. Punch (6) for implementing the method according to claim 8, characterized in that it comprises means (11) for pre-cutting, first (12) punching means intended to form the housing (3), second (13) punching means s5 forming at least one groove (15) on the surface defining the housing (3) and means (14) for scraping this surface.