EP0340368A1 - Apparatus for making grooves on a workpiece - Google Patents

Abstract

The invention relates to an apparatus for forming grooves on a cylindrical surface (3) of a workpiece (1) comprising: - a support (5, 16) intended for holding the workpiece (1); - rotatable forming rolls (29, 30) mounted in a stand surrounding the support; and, - means for impressing, to the support and to the stand, a relative translational movement parallel to a fixed direction, the rolls each rotating about an axis orthogonal to the fixed direction in order to enable the grooves to be produced in the workpiece after the latter has passed between the forming rolls. According to the invention, the apparatus comprises at least two identical rings (23 and 24) of rotatable rolls (29 and 30) uniformly angularly distributed, the rings being disposed one on top of the other and being angularly offset with respect to each other about the direction. Application to the production of gear wheels or grooved pulleys. <IMAGE>

Description

The present invention relates to a device for forming grooves or the like on a cylindrical surface of a part by deformation of the metal, making it possible for example to obtain sprockets or toothed pulleys.

In a particular, although not exclusive, application, these toothed pulleys are intended to ensure mechanical transmission, via a toothed belt, between a first mechanical member, such as a camshaft of an internal combustion engine. , and a second mechanical member such as the crankshaft of this engine; the transmission between two toothed pulleys each disposed on one of said members then controls the distribution of the engine.

Devices are already known for forming grooves or the like (grooves) on cylindrical surfaces of parts. For example, French patent FR-A-2 482 483 describes a device comprising a support intended to hold the generally cylindrical part and most often made of stamped sheet metal, and a plurality of rotary forming rollers mounted in a cage surrounding the support , each roller being inserted in a housing being oriented towards said part. The device also comprises means for imparting to the support of the part and to the cage carrying the rollers a relative movement of translation parallel to a fixed direction, the rollers rotating, each, around a geometric axis orthogonal to the fixed direction, to allow, during the passage of the part between the forming rollers, the production of the grooves on the cylindrical surface of the part.

A strain ring, arranged around the cage and in contact with the top of the different rollers, absorbs the radial forces acting on all of the rollers during forming grooves. Thus, for each groove to be formed on the cylindrical surface of the part there corresponds a forming roller positioned in a housing of said cage.

Consequently, when the number of grooves to be produced on the cylindrical surface is large, consequently causing the installation of an identical number of rollers in the cage, it is obvious that the mounting of the rollers in the cage, that the actual implementation thereof, and that the maintenance which follows, prove to be delicate, problematic and costly. In addition, the number of forming rollers being large, the latter therefore have a reduced thickness, which can cause mechanical deformation and faster wear of the rollers due to the radial forces acting directly on the rollers when forming the grooves. on the cylindrical surface of the part.

The present invention aims to overcome these drawbacks and relates to a device for forming grooves or the like on a cylindrical surface of a part, which is of an original design allowing in particular the production of a large number of grooves while being easy to maintain, and whose forming rollers offer very good resistance to radial forces, thanks to their particular mounting.

To this end, the device for forming grooves or the like on a cylindrical surface of a part of the type comprising:
- a support intended to hold said part;
- a plurality of rotary forming rollers mounted in a cage surrounding said support; and,
- Means for printing on said support and on said cage a relative translational movement parallel to a fixed direction, said rollers rotating, each around of an axis orthogonal to said fixed direction, to allow, during the passage of said part between the forming rollers, the production of grooves or the like thereon, is remarkable, according to the invention, in that it comprises at least two identical rings of rotating rollers regularly distributed angularly, said rings being arranged one above the other and being angularly offset relative to each other around said direction, so that each roller one is, in projection, in an intermediate position between two adjacent rollers of the other ring.

Thus, thanks to the invention, the N grooves to be formed on the cylindrical surface of said part are executed in two successive phases, which are carried out, on the one hand, by the N / 2 rotary rollers mounted in the first ring, and on the other hand, by the N / 2 rotary rollers mounted in the second ring. By the arrangement one above the other of the two crowns, it is thus possible to make a large number of grooves on the cylindrical surface without having a considerable number of rollers on the same crown, as was the case in the prior art.

According to another characteristic of the invention, each roller can be mounted to rotate freely on a fixed axis linked to the respective crown. In a preferred embodiment, each of said axes carrying a rotary roller is mounted at its ends in radial sides coming from each of the rings.

Thus, thanks to this arrangement, the radial forces appearing during the formation of the grooves on the rollers are taken up by the axes mounted in the sides of the crowns. As a result, the forming rollers have a higher wear resistance, and can even make larger grooves.

In a preferred embodiment, each rotary roller can have at least two forming edges intended to form two adjacent grooves on said part. This embodiment thus makes it possible to reduce the number of rotary forming rollers, since, for N grooves to be formed on the cylindrical surface of the part, the first and second superimposed crowns each comprise N / 4 rollers of two forming edges. Each roller therefore has a width twice that of the rollers having a forming edge, which thus increases their mechanical resistance criteria.

• La figure 1 est une vue schématique en coupe d'un dispo­sitif de formage selon l'invention, montrant la pièce 1 après son passage entre les deux couronnes.
• La figure 2 représente deux demi-vues en coupe, respective­ment selon la ligne A-A de la figure 1 montrant le passage de la pièce entre les galets de formage de la première couronne, et selon la ligne B-B de la figure 1 montrant le passage de la pièce entre les galets de formage de la seconde couronne.
• La figure 3 est une vue, à une échelle agrandie, d'un galet de formage réalisant des rainures correspondantes sur ladite pièce.

The figures of the appended drawing will make it clear how the invention can be implemented. Identical references designate similar elements.

• Figure 1 is a schematic sectional view of a forming device according to the invention, showing the part 1 after its passage between the two crowns.
• FIG. 2 represents two half-views in section, respectively along the line AA in FIG. 1 showing the passage of the part between the forming rollers of the first ring, and along the line BB in FIG. 1 showing the passage of the part between the forming rollers of the second ring.
• FIG. 3 is a view, on an enlarged scale, of a forming roller producing corresponding grooves on said part.

The device of the invention shown in FIGS. 1 and 2 is intended for the formation of grooves or grooves on the cylindrical, for example external, surface of a part 1. The latter, before it is placed in the device, is obtained, although not exclusively, by stamping and comprises a bottom 2 and a cylindrical side wall 3, on the outer surface 4 of which it is desired to form grooves.

The device comprises a support 5 intended to hold the part 1 during the forming operation, which support 5 is capable, in this embodiment, of sliding axially with respect to a fixed frame 6, inside which the support is arranged , in a vertical direction in Figure 1 which corresponds to the geometric axis 7 of the cylindrical part. The axial sliding of the support relative to the frame is produced by two sets of columns, parallel to the axis 7. A first set of columns 8, one of which is shown in FIG. 1, are fixed to the lower part 9 of the support 5 and can slide in respective orifices 10 of corresponding diameter provided in the base 11 of the frame 6. Conversely, a second set of columns 12, one of which is shown in this same figure, are fixed to the base 11 of the frame 6, and on which can slide the support 5 via holes 14 provided in the lower part 9 thereof. By this arrangement, precise axial guidance of the support 5 is obtained with respect to the frame 6 in the vertical direction, that is to say the axis 7.

The support 5 consists of a matrix 16 on which the part 1 is arranged. The matrix 16 has a shape similar to that of the part and has an external profile corresponding to the internal profile of the cylindrical side wall 3 of the part after being produced thereon. grooves obtained by mechanical deformation of the metal of the cylindrical side wall 3.

The part 1 is positioned in rotation by at least one centering pin 18, arranged on the matrix 16. The axis 7 is therefore common to the part 1 and to the matrix 16 of the support 5.

As can be seen in FIG. 1, the part 1 is held axially on the die 16 by a second die 19, the face of which comes into contact with the external face of the base 2 (the internal face of the latter resting on the matrix 16) has an analogous shape complementary to this.

There is provided in the second die 19, a hole in which the centering pin 18 engages, in order to ensure a suitable positioning between the dies and the part, coaxially with the axis 7. Schematically, the second die 19 is fixed by means of screws to a barrel 20, itself secured, by means of screws, to an upper plate 21. The two dies enclosing the part are linked to each other by any suitable connecting means not shown.

According to the invention, the device comprises, in this embodiment, two identical rings 23 and 24 coaxial with the axis 7, and arranged one, 23, above the other, 24, which rings surround the assembly consisting mainly of support 5, dies 16 and 19, and of part 1.

The crowns 23 and 24 are fixed to the frame 6 by means of a plurality of threaded rods 25, one of which is shown in FIG. 1. End spacers 26 as well as an intermediate spacer 27 separating the two crowns are also provided. The centering and positioning of these different parts on top of each other, all coaxial with the axis 7, are ensured by a plurality of centering pins or the like, like that referenced at 28 in FIG. 1.

The rings 23 and 24 each carry a plurality of rotary forming rollers 29 and 30 respectively in identical numbers. The rollers 29 and 30 are regularly distributed angularly with respect to the axis 7, and each rotate around a material axis 31 orthogonal to the axis 7. The axes 31 are mounted at their ends in holes made in radial sides 32 from crowns 23 and 24 (Figures 1 and 2).

Advantageously, as can best be seen in FIG. 2, the two superimposed crowns 23 and 24 are angularly offset relative to each other around the axis 7 or the fixed direction, so that each roller, by example 29 of the upper ring 23, is, in projection in the plane of these rings, in the middle position between two adjacent rollers 30 of the lower ring 24. In addition, each forming roller 29 or 30 advantageously comprises, two forming edges 33 (Figures 2 and 3).

Consequently, for a number of grooves N to be produced on the side wall of the part 1, it suffices to provide on each ring angularly offset from one another, a number N / 4 of rotary rollers with two edges forming to obtain the N grooves desired.

Means, which may be of the pneumatic type, and secured for example to a press, (not shown in the figures) make it possible to print, in this embodiment, on the mobile assembly consisting of the support 5, the dies 16 and 19 enclosing the part 1, of the barrel 20 and of the upper plate 21, a translational movement relative to the frame 6 and to the rings 23 and 24 carrying the rollers 29 and 30, along the axis 7.

The operating cycle of the device is carried out as follows: the aforementioned movable assembly is in the high position, position for which the part 1 has been shown in dotted lines by the reference 35 in FIG. 1. When put into action pneumatic means, causing the axial displacement of the movable assembly towards the base of the frame 6, which displacement is guided by the sets of columns 8 and 12, the part 1 passes through rotating rollers 29 with two forming edges 33 of the upper ring 23 (Figure 2, left part), which results in the deformation of the metal constituting the cylindrical side wall 3, obtaining on the outer surface 4, half of the grooves 36 to be formed.

Advantageously, the radial forces created during the formation of the grooves 36 by the forming edges 33 of the rollers are taken up by the pins 31 mounted in the radial sides 32 of the ring 23.

The descent of the movable assembly continuing, the part 1 passes through the rotating rollers 30 with two forming edges 33 of the lower ring 24 (FIG. 2, right part), which leads, in an identical manner, to obtaining the complementary grooves 36 on the outer surface 4 of the part 1. The N grooves are then formed. The movable assembly is then in the position illustrated in FIG. 1. The operating cycle of the fluidic means is reversed to return the assembly to its initial position. The part 1 produced is removed manually, or even automatically from the matrix 16.

In an alternative embodiment, the operation could be carried out reciprocally, the frame carrying the roller crowns being movable, and the part then being fixed.

Figure 3 allows to further visualize the embodiment of the grooves 36 by the forming edges 33 of a roller, for example 30, of the lower ring 24. The cylindrical side wall 4 of the part 1 then has, after the formation of the grooves , an inner profile corresponding to the outer profile 38 of the matrix 16. Of course, the shape of the grooves 36 made on the outer surface 4 of the wall 3 by the edges 33 of the rollers 29 and 30 could be different. In addition, it can be seen that, in this FIG. 3, the forming planes 39 of the edges 33 converge towards the axis 7 so that they produce identical grooves.

It was previously indicated that the part 1, obtained by a prior stamping operation, was directly disposed on the matrix 16 of the device according to the invention. However, it is obvious that this part 1 could already have been the subject of a preforming of the grooves 36 on another device, before being placed on the matrix 16 of said device.

Also, after the grooves 36 have been produced on the part 1 by the device of the invention, provision could also be made for an operation for finishing and calibrating the grooves on another device.

Although the device described consists of two crowns offset angularly, so that each roller of one is, in projection, in the middle position between two adjacent rollers of the other crown, it goes from so that, because the rollers of the crowns are, in projection, regularly distributed angularly with respect to the direction, the device could include a greater number of identical crowns, so that each roller of a first crown is in projection , in the intermediate position between two adjacent rollers of a second ring.

Claims (7)

1 - Device for forming grooves or the like on a cylindrical surface (3) of a part (1) of the type comprising:
- a support (5.16) intended to hold said part (1);
- a plurality of rotary forming rollers (29, 30) mounted in a cage surrounding said support; and,
- Means for printing on said support and on said cage a relative translational movement parallel to a fixed direction, said rollers each rotating about an axis orthogonal to said fixed direction, to allow, during the passage of said part between the forming rollers, making grooves or the like thereon,
characterized in that it comprises at least two identical rings (23 and 24) of rotary rollers (29 and 30) regularly distributed angularly, said rings being arranged one above the other and being angularly offset one relative to each other around said direction, so that each roller (29 or 30) of one (23 or 24) is, in projection, in an intermediate position between two rollers (30 or 29) adjacent to the '' other crown (24 or 23). 2 - Device according to claim 1,
characterized in that each roller (29 or 30) is mounted to rotate freely on a fixed axis (31) linked to the respective crown (23 or 24). 3 - Device according to claim 2,
characterized in that each of said axes (31) carrying a rotary roller (29 or 30) is mounted at its ends in radial sides (32) coming from each of the rings (23 or 24). 4 - Device according to one of claims 1 to 3,
characterized in that each rotary roller (29 or 30) has at least two forming edges (33) intended to form two consecutive grooves (36) on said piece. 5 - Device according to any one of claims 1 to 4,
characterized in that said crowns (23 and 24) are separated from each other by an intermediate spacer (27), end spacers (26) being arranged on either side of said crowns (23 and 24 ). 6 - Device according to one of claims 1 to 5,
characterized in that, in projection, the rollers for forming said crowns are regularly angularly distributed. 7 - Device according to any one of the preceding claims,
characterized in that it comprises two identical rings (23 and 24) of rotary rollers (29 and 30) regularly distributed angularly, the two said rings being arranged one above the other and being angularly offset one by relative to each other around said direction, so that each roller (29 or 30) of one (23 or 24) is, in projection, in the middle position between two rollers (30 or 29) adjacent to the other crown (24 or 23).

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