FR2845625A1 - Method of making drive plate for motor vehicle transmission has metal sheet drawn to form peripheral thickening and cut to form fixing holes - Google Patents

Abstract

The method of making a drive plate for a motor vehicle involves drawing a metal sheet blank (21) of circular shape to provide a peripheral thickening (29). The blank is cut out to form fixing holes (31) to the web of the crankshaft and the gearbox input. Notches are cut (33) on the circumferential edge of the thickened area to form a timing marker.

Description

Method of manufacturing a gearbox drive plate

  for vehicle and gearbox drive plate

speeds obtained.

  The present invention relates to a gearbox drive plate with an ignition target for a vehicle and more particularly a drive plate for the gearbox input device of a motor vehicle, this plate comprising a target on the periphery.

  Such a plate is intended in particular for automatic gearboxes or variable transmission boxes.

  There is known a gearbox drive plate for a motor vehicle carrying an ignition pattern on the periphery and forming a motor / gearbox connection of the vehicle. This tray comprises a central part in the form of a flat disc and a peripheral part in the form of a crown which has on its edge

  cylindrical at least one notch forming test pattern.

  Conventionally, such a plate is obtained by a process of

  manufacturing comprising four successive stages.

  In a first step, a planar blank shaped like a disc is stamped axially so as to create a ring on its periphery.

  annular offset axially from the initial plane of the blank.

  In a second step, this crown is cut perpendicular to the axial direction using a clipping tool. In a third step, the remaining edge falls in the axial direction, this by means of a stamping tool so as to obtain the crown of the plate, the cylindrical peripheral edge of which is

axial orientation.

  Finally in a fourth and final step, 30 notches are made in the wall of the crown near its peripheral edge using a notching tool, mounted on a machine comprising a dividing mandrel and which is radially movable . We

  obtains notches spaced at regular angular intervals.

  Such a method has drawbacks. It is known that the plate 35 or ignition cage of the type described above cannot admit of

  lack of cylindricity greater than a strict tolerance determined.

  However, such a process generates during its various stages a significant deformation of the outer diameter of the crown and which is hardly compatible with the aforementioned tolerance. In addition, the

  crown is subject to bending with centrifugal force of rotation.

  Finally, the cutting of the notches is subject to a cumulative positioning error 5 on the crown and represents an operation

relatively long and expensive.

  The invention aims to remedy these drawbacks and proposes a method of manufacturing a gearbox drive plate for a vehicle, of the type comprising an ignition target on the periphery and intended to be fixed on one side to the engine crankshaft and on the side opposite the vehicle gearbox input device, characterized in that it essentially comprises the following successive stages: - the deformation by stretching of material of a sheet metal disc-shaped blank so as to thicken its periphery in a regular annular portion, - the cutting on the blank of the fixing holes of the plate to the engine crankshaft and to the gearbox input device of the vehicle, and - the cutting of the notches on the outer circumferential edge of said annular portion of the blank so as to form the ignition target of the

tray made.

  The deformation of material in order to form said annular portion of the periphery of the blank, obtained in a known manner by pressure rolling of the stretched material between opposite rollers, is advantageously developed in a flared shape towards the periphery

  with symmetry relative to the plane of the blank.

  This shape can be conical over a portion of the diameter and then straight development, preferably parallel to the plane of the blank,

to the edge of the periphery.

  The step of cutting the fixing holes is advantageously obtained by means of a cutting punch device passing through the

blank by means of a press.

  The step of cutting the notches is obtained by means of a notching die applied by press coaxially on the blank, said die comprising a plurality of teeth for cutting the notches.

  notches on the blank arranged regularly on its periphery.

  The notches are advantageously teeth forming a

  regular notching of the periphery.

  This arrangement results in a quicker preparation of the tray

  relative to that of the aforementioned prior art.

  The thickened circumference of the plate is rigid and is therefore no longer subject to deformation. In addition, it increases the inertia of rotation of the driven masses for better balance of rotation without

increase mass.

  Finally, we obtain a much better positioning accuracy 10 of the ignition target, which is a function of that of the tool and therefore

easier to master.

  The invention also relates to the gearbox drive plate.

  speed for vehicle obtained by the above method.

  An exemplary embodiment of the invention is now described with reference to the accompanying drawings, in which - Figure 1 shows in a cross-sectional view a drive plate of the prior art, disposed between the input device of a gearbox and the crankshaft of a vehicle engine, - Figure 2 shows in a view similar to the previous one 20 gearbox drive plate according to the invention, and

  - Figure 3 is an elevational view of the tray of Figure 2.

  To facilitate understanding of the gearbox drive plate according to the invention, there is shown a known drive plate 1, produced according to the method described in the preamble. Thus, the plate 25 1, fixed to the cover / torque converter 3 of the gearbox and to the end of the engine crankshaft 5, by means of suitable studs and corresponding nuts is in the form of a metal disc provided with 'An annular ring 7 after folding of the blank of the disc. The crown 7 is developed parallel in section to the axis of the plate and covers, with little play, part of the width of the torque converter 3. The crown 7 further comprises, along a line of circumference, a plurality of notches 9 in the form square windows cut in its wall. These notches 9 are positioned regularly on the circumference line and opposite 35 a sensor device 11 with variation of magnetic fields, connected itself to the computer device of the vehicle (not shown), this device being able to manage the movement of the gearbox and for example the transmission of gear ratios depending on the speed

motor read by the sensor.

  In the figure, we see the crown fold 7 of the plate from stamping and whose cylindricity is difficult to obtain. Furthermore, it can deform at high rotational speed with centrifugal force

  induced. This is detrimental to the reading of the aforementioned sensor.

  In addition, the cutting of the slot windows 9 by means of a tool

  radially movable is relatively long to execute and imprecise, cumulating the positioning tolerance games from one notch to the other.

  According to the invention, it is carried out in another way as illustrated

  below with reference to Figures 2 and 3.

  We use for the realization of the box drive plate

  speeds according to the invention a metal blank 21 in the form of a disc and of the same thickness as previously. (2 mm).

  The blank is first deformed by a first forming device with conventional pressing rollers (not shown) to form a circular fold 23 substantially on the central part of the disc 21. This fold 23 makes a slight radial offset from the wall to adapt the fixing by 20 three studs 25 to 1200 at an angle from one another, of the plate 21 to the torque converter 27 or any other gearbox input device. This operation is similar in the realization of the plate

known 1 above.

  Note that such a fold 23 is not necessary, the blank 25 may remain flat, or it could have several folds.

  Then, a pressure roller device, arranged substantially on the periphery of the disc, always carries out a progressive drawing of the material so as to push it back towards the periphery and by thickening the latter. A regular peripheral annular portion 30 is obtained 29. The shape of this periphery portion 29, imparted by the pressure rollers is of conical development flared upwards (periphery) and straight portion outside. The thickness of this straight portion can be 5 to 10 mm. Its depth must be expected to be sufficient

  for cutting notches within it, as described below.

  During a third step, punches press cut the fixing holes 31 to the engine crankshaft and to the converter.

gearbox torque.

  Finally, during a fourth step, a notched notching matrix is applied by press coaxially to the blank on its thickened periphery 29. This matrix cuts the notch teeth 33 of the plate on its periphery by means of a single press. These teeth or notches 33 are of rectangular section, arranged at

  regular interval around the periphery of the plateau. They form the test pattern of the plate facing the sensor 35 as in FIG. 1. The precision of cutting the notches on the plate corresponding to the shape of the tool is imparted by the tool itself, which is formed from 10 specifically for the dimensions of the tray to be produced.

  This demonstrates the simplicity of the process for producing the gearbox drive plate according to the invention and its ability to control the precision of the positioning of the ignition target on the plate. Naturally, variant embodiments fall within the scope

of the invention.

  Thus, the shape of the enlarged periphery portion 29 of the plate

  can vary as well as the shape of the notch teeth 33 etc ...

Claims (8)

  1. A method of manufacturing an ignition target gearbox drive plate for a vehicle, of the type comprising an ignition target (33) at the periphery and intended to be connected on one side to the engine 5 and on the side opposite the gearbox input device (27), characterized in that it essentially comprises the following successive steps: the deformation by drawing of material of a sheet metal blank (21) in the form of a disc so as to thicken its periphery according to a regular annular portion (29), - the cutting on the blank (21) of the fixing holes (31) of the plate to the engine crankshaft and to the vehicle gearbox input device, and - cutting the notches (33) on the outer circumferential edge 15 of said annular portion (29) of the blank so as to form the target of ignition of the plate produced.   2. Method of manufacturing a box drive plate   speeds, according to claim 1, characterized in that the deformation of material at the periphery (29) of the blank is obtained by stretching the material between opposite rollers.   3. Method for manufacturing a gearbox drive plate   speeds, according to claim 2, characterized in that the annular portion of the blank from the deformation of material (29) is of flared shape towards the periphery with symmetry relative to the plane of the blank 25 (21).   4. Method of manufacturing a box drive plate   speeds, according to claim 3, characterized in that said flared shape is conical over a portion of the diameter of the blank then straight development, preferably parallel to the plane of the blank 30 (21), to the periphery.   5. Method of manufacturing a box drive plate   speeds, according to one of claims 1-4, characterized in that the step of cutting the fixing holes (31) is obtained by means of a cutting punch device passing through the blank (21) by means of a press.   6. Method of manufacturing a box drive plate   speeds, according to one of claims 1-5, characterized in that   the step of cutting the notches (33) is obtained by means of a notching die applied by press coaxially on the blank (21), said die comprising a plurality of teeth for cutting the notches   notches (33), regularly arranged at the periphery.   7. Method for manufacturing a gearbox drive plate   gears according to claim 6, characterized in that said notches (33) have a regular rectangular toothed or notched section.   8. Gearbox drive plate with test pattern   for a vehicle, characterized in that it has an enlarged peripheral edge 10 (29), provided with notch teeth (33) forming an ignition target.