Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D53/00—Making other particular articles
  • B21D53/88—Making other particular articles other parts for vehicles, e.g. cowlings, mudguards
  • B21D53/90—Making other particular articles other parts for vehicles, e.g. cowlings, mudguards axle-housings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/02—Stamping using rigid devices or tools
  • B21D22/025—Stamping using rigid devices or tools for tubular articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D53/00—Making other particular articles
  • B21D53/88—Making other particular articles other parts for vehicles, e.g. cowlings, mudguards

Definitions

• Tooling for manufacturing a closed section cross member comprising a matrix and / or a punch of adaptable length, and corresponding manufacturing method.
• the field of the invention is that of motor vehicles. More specifically, the invention relates to flexible axles for motor vehicles.
• a flexible axle comprises two longitudinal arms each carrying a wheel mounting bracket and connected by a transverse connecting member called cross member or profile.
• the principle of flexible axles reconciles a high stiffness in bending and a relative flexibility in torsion. In general, it is through the geometry of the section of the cross member, via its bending and torsional inertia, that the desired compromise between flexural stiffness and (relative) torsional flexibility is achieved.
• the flexible axles are indeed tainted with a number of limitations among which a delicate compromise between longitudinal and transverse stiffness and durability conditioned by the endurance resistance of each of their components, subjected to significant elastic deformations.
• the connecting element, or through, is therefore one of the most difficult components to develop, especially in terms of endurance and behavior.
• the crossbar connecting the longitudinal arms is made according to two different technologies.
• the crossbar is made from a folded sheet metal element (or stamped) so as to provide a section having a shape of "U", "V” or “L".
• These sleepers generally require to be associated with an anti-roll bar, providing torsional stiffness to the axle.
• the second technology consists in integrating the anti-roll stiffness function at the transom.
• the cross is manufactured from a tube generally having a circular section, the tube being subjected at least in its central part to a deformation step (at the end of which a portion of the wall is crushed against another portion of the wall) to obtain the desired stiffness in torsion and flexion (examples: Volkswagen 806 (registered trademarks) or Opel Zafira (registered trademarks)).
• a deformation step at the end of which a portion of the wall is crushed against another portion of the wall
• the diversity of anti-roll stiffness according to the needs is ensured by modification of the shape of the section of the cross-member and / or modification of the thickness of the tube.
• the invention applies to sleepers made according to this second technology, these being commonly referred to as “closed-profile sleepers” or “closed-section sleepers”.
• the cross tube is only deformed in a transverse portion to reduce torsional stiffness, and retains stronger torsion sections (eg circular) at the ends, to facilitate connection to the suspension arm by welding.
• the crossbar of a flexible axle is characterized by a high stiffness in bending and a low torsion stiffness, the latter must be precisely calibrated (associated with the anti-roll stiffness of the axle.
• One of the factors influencing the anti-roll stiffness is the dispersion over the thickness of the tube.
• the problem is to decrease the sensitivity of the anti-roll stiffness of the axle to the dispersions on the thickness of the tube.
• the order of magnitude is such that a dispersion of +/- 0.1 mm the thickness of the tube can generate of the order of three times the tolerance interval of the anti-roll stiffness of the axle of the specifications.
• a first solution is to work with tube suppliers to control dispersions on the thickness of the tube (from a rolling process and welding), using a sorting method.
• the tube sheets are connected at each end of the cross-member by a "clinching" method (puncturing of one sheet in the other by punching).
• the invention particularly aims to overcome the disadvantages of the prior art.
• the object of the invention is to propose a technique for manufacturing a cross section with a closed section for a flexible axle which makes it possible to better control the dispersion of the torsional stiffness of the crossbar compared to the solutions of the prior art.
• the invention also aims to provide such a technique that is simple in design and easy to implement.
• the invention also aims to propose a manufacturing method corresponding to such a technique.
• a tool for manufacturing a cross-section with a closed section intended to connect two longitudinal arms of a flexible axle of a motor vehicle said tooling comprising at least one die intended to cooperate with a punch to form on said closed section of said crosspiece a torsion zone length, and means for holding said crosspiece in position, characterized in that said matrix and / or said punch are adaptable in length to adapt said length of said torsion zone.
• said matrix and said punch each comprise at least two parts that may be spaced apart / close to each other.
• said two parts of said die and / or said punch may be actuated by at least one jack.
• said two parts of said matrix and / or said punch are maintained in the extension of one another using screwing means.
• the tooling preferably comprises a set of shims capable of being interposed between said two parts of said die and / or said punch.
• the set of shims can then comprise a variety of shims of different thicknesses to cover a given amplitude, with the desired accuracy.
• said means for holding in position comprise at least one variable-displacement mandrel.
• Such mandrels contribute to the modularity of the tooling, allowing to adapt it according to both the thickness of the cross member and its length.
• the invention also relates to a method of manufacturing a cross-section with a closed section intended to connect two longitudinal arms of a flexible axle of a motor vehicle, using a tool comprising at least one die intended to cooperate with a punch. to form on said closed section of said cross member a torsion zone length, and means for holding said crosspiece in position, characterized in that it comprises a step of adjusting the length of said matrix and / or said punch in order to adapting said length of said torsion zone.
• the method comprises a preliminary step of calculating said length of said torsion zone as a function of the desired torsional stiffness for said cross-member and the wall thickness of said section.
• the method comprises a step of adjusting the stroke of two mandrels forming said holding means in position.
• Figures 1 to 3 are each a view of a manufacturing step of a cross section closed according to the prior art;
• Figures 4a, 4b, 5 and 6 are views for illustrating the influence of the torsion area of a cross member on the torsion stiffness thereof;
• Figure 7 is a schematic view of the general principle of the invention;
• Figure 8 is a schematic view of a preferred embodiment of the invention;
• FIGS. 9 to 11 are graphs illustrating an example of a torsion stiffness tolerance range obtained by virtue of the invention as a function of a thickness dispersion and a given working length variation.
• a cross section with a closed section is manufactured according to the prior art from a tube 1 on which, by means of a press, it acts by deformation of its section. to achieve a torsion zone.
• the conventional tooling comprises a punch 2 and a die 3 actuated by a press and intended to cooperate to form the torsion zone, and mandrels 4 intended to bear against the ends of the tube 1.
• the tube is placed in the press, and the mandrels are advanced against the tube so as to lock it; then we close the press.
• FIG. 2 illustrates the step of forming the torsion zone over a given and fixed length, the die 3 and the punch 2 crushing between them the tube.
• the press is opened (the die 3 and the punch 2 are therefore spaced apart from each other) and the mandrels are moved away from the tube (FIG. 3).
• stat zone of a cross member with a closed section denotes the zone L corresponding to the portion central of the cross.
• the geometric profile of the section of the tube, the thickness of the tube and the length of the torsion zone are factors of order 1 for obtaining the torsional stiffness of the crossbar.
• the variation in the length ⁇ L of the torsion zone varies the torsion stiffness R of the crossbar as follows: if L increases, R decreases, and conversely .
• the crossbar when the length of the torsion zone L is minimal, the crossbar has a maximum torsional stiffness (FIG. 5). Conversely, when the length of the torsion zone L is maximum, the crossbar has a minimum torsional stiffness (FIG. 6).
• the principle of the invention illustrated by FIG. 7 lies in making the punch 2 and the matrix 3 adaptable in length so that they allow variations in length ⁇ L corresponding to the length of the torsion area sought.
• the punch 2 and the die 3 each have two parts, respectively 2a, 2b and 3a, 3b, that can be moved closer together or apart from one another. to obtain a variation ⁇ L.
• the spacing between the parts 2a, 2b on the one hand, and the parts 3a, 3b on the other hand, is obtained by interposing between them one or more shims 6.
• the number and the thickness of the shims are chosen according to the desired ⁇ L.
• mandrel races 4 are controlled by hydraulic cylinders (not shown) ensuring the translation of the mandrels.
• the adaptive adjustment of the tooling that has just been described is performed between each burst of production (a burst being defined by a batch of tubes characterized by an average thickness value of the tubes), in press, with or without partial dismantling. tooling.
• the length of the torsion zone is calculated as a function of the thickness of the tube, this for a stiffness fixed by specifications.
• FIGS. 9 to 11 are graphs illustrating an example of a torsion stiffness tolerance range obtained by virtue of the invention as a function of a thickness dispersion and a given working length variation.
• the graph of FIG. 9 indicates a thickness dispersion (between 3.35 mm and 3.55 mm) on a batch of tubes.
• the graph of Figure 10 indicates working length variations (corresponding to the length of the torsion zone).
• the graph of Figure 11 shows the output data for torsional stiffness.
• the variation of the working length (denoted L on FIG. 4a) between 618 and 700 mm makes it possible to respect a tolerance tolerance of stiffness of ⁇ 2 m.daN / 0 for a tolerance on the tube thickness of ⁇ 0.1 mm.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Vehicle Body Suspensions (AREA)
• Body Structure For Vehicles (AREA)
• Mounting, Exchange, And Manufacturing Of Dies (AREA)
• Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Shaping Metal By Deep-Drawing, Or The Like (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=36540250

Family Applications (1)

Country Status (8)

Families Citing this family (14)

Family Cites Families (9)

• 2005
  • 2005-10-04 FR FR0510131A patent/FR2891480B1/fr not_active Expired - Fee Related
• 2006
  • 2006-10-04 US US12/089,134 patent/US20090071220A1/en not_active Abandoned
  • 2006-10-04 WO PCT/FR2006/050990 patent/WO2007039703A1/fr active Application Filing
  • 2006-10-04 EP EP06820253A patent/EP1933999B1/de not_active Not-in-force
  • 2006-10-04 JP JP2008534059A patent/JP2009509774A/ja active Pending
  • 2006-10-04 DE DE602006009531T patent/DE602006009531D1/de active Active
  • 2006-10-04 PL PL06820253T patent/PL1933999T3/pl unknown
  • 2006-10-04 AT AT06820253T patent/ATE444129T1/de not_active IP Right Cessation

Non-Patent Citations (1)

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