FR2716944A1 - Link outer part mfg. process - Google Patents

Abstract

The link outer part mfg. process comprises first fitting inserts (e.g. 6) in a pre-moulded hexagonal jacket (5) of easily deformable material, then pushing a punch with external measurements corresponding to internal measurements of the external part into the unit formed by the inserts and jacket, and then partly deforming the jacket radially inwards. The link made in this way has a jacket of aluminium alloy. The guide grooves (10) are formed by an individual insert which may also include a guide track.

Description

 The invention relates to a method for manufacturing an outer seal part, in particular for a tripod seal, comprising three guide grooves extending parallel to the axis and each having two guide paths, in which assemblies are guided. roller each composed of an inner roller and an outer roller mounted to rotate on the inner roller, and each arranged on a pin oriented radially with respect to the axis of the joint and being in correspondence with the guide grooves, the guide grooves being formed, at least in the region of the guide paths associated therewith, by inserts made of a hardened material. The invention also relates to an outer seal part produced by this method.

 It has already been proposed to construct an outer seal part for a tripod seal, made of a fiber-reinforced plastic material, and to produce the guide grooves by steel inserts (see document FR-A1 669 979). The disadvantage of the outer joint part described here, however, lies in the fact that due to the high production of heat generated in the joint due to friction, the temperature stability of the fiber-reinforced plastic material is not not sufficient. Over time, creep phenomena are established under the effect of the torque force, so that the shape stability of the outer seal part is no longer guaranteed.

According to another proposal, the envelope is made, for example, of cast aluminum, the inserts being directly embedded in the molding (document
DE-OS 3020193).

 A serious drawback of this proposal lies in the fact that the inserts, after their insertion into the envelope, are not oriented sufficiently precisely. Also, this results in the imperative to carry out a resumption of machining, for example by grinding, which involves additional costs.

 The object of the invention is to provide a method of manufacturing an outer seal part for a tripod seal, which, for a composite construction method, requires a minimum of machine machining, and makes it possible to obtain high manufacturing precision, of the finished product.

 In accordance with the invention, this object is achieved thanks to the following solution, characterized in that the inserts, during a first step, are inserted in a correspondingly pre-shaped envelope, made of an easily deformable material, and having a substantially hexagonal configuration in terms of its external shape, in that during a second step, a forming mandrel corresponding, in terms of its external dimensions, to the internal contour of the external joint part, to be produced, is introduced into the interior of the composite assembly consisting of the inserts and the envelope, and in that during a third step, the envelope is deformed radially inwards by at least partially enclosing the inserts, the inserts being maintained in a defined position, relative to each other, by the forming mandrel.

 The advantage of the method of manufacturing an external seal part for a tripod seal, according to the invention, resides in the fact that the inserts whose shaping and machining are completed, are maintained, during the operation compression, in a precisely defined position, with respect to each other, by the use of a forming mandrel, which makes it possible to eliminate any resumption of machining after the completion of the manufacture of the outer seal part .

 Before the compression operation, the inserts can be easily subjected as individual parts, to the necessary heat treatments, and also can be brought to their appropriate functional configuration.

 According to an advantageous configuration of the method, the force intended for the deformation directed towards the interior, of the envelope, is applied by at least three jaws of formation being able to carry out a work advance directed radially towards the interior and acting between the paths. guide.

 This process is distinguished by a simple construction method of the forming tools.

 According to an advantageous characteristic of the invention, the force intended for the deformation directed radially inwards is applied by six forming jaws which can carry out a radial working advance, and two sets of forming jaws are used having different support surfaces, urging the envelope, the support jaws of different support surfaces being arranged alternately.

 An advantageous effect obtained in the case of the use of this process lies in the fact that the compression stresses inside the envelope are thus distributed in a substantially uniform manner over the cross section.

 According to another configuration of the invention, recesses on the envelope, which have an undercut in the radial direction, are biased by compression pins of corresponding shape, arranged on the bearing surfaces, the compression pins being introduced axially into the recesses.

 The recess on the envelope, provided with an undercut and oriented in the axial direction, makes it possible to obtain a priority distribution of the compressive stresses in areas requiring high deformations.

 According to another advantageous characteristic of the invention, the pre-shaped envelope is manufactured by spinning.

 The realization of the envelope pre-shaped by a spinning process, allows manufacturing and economic shaping of the envelope.

 According to another characteristic of the invention, the inserts are provided with notches or notches oriented perpendicular to the axis of the joint and intended for axial fixing.

 As the inserts are at least partially enclosed by the material of the envelope to be deformed, there is obtained, without additional cost, an axial stop of the inserts in the envelope.

 A variant of the method for manufacturing the external seal part is characterized in that the connection of the inserts is generated by a deformation directed radially outwards, of ribs arranged between the guide grooves, the compression pressure directed radially towards the being applied by a conical compression mandrel, stressed by an external force, displaced axially towards the inside of the external joint part and acting on compression jaws which can move radially, and in that the compression pressure acting radially towards the outside is absorbed by forming jaws resting on a support ring.

 In the outer joint part produced according to the process which has just been mentioned, the casing is made of an aluminum alloy.

 The use of an aluminum alloy for the envelope makes it possible to obtain good deformability of the envelope, and in addition, a certain reduction in weight.

 According to an advantageous configuration of the invention, the guide grooves are each formed by an individual insert.

 According to another embodiment, the guide grooves are formed by separate inserts, each associated with a guide path.

 The use of inserts, each associated with a single guide path, makes it possible to guarantee simple and economical manufacture of the inserts.

 According to another advantageous characteristic of the invention, two neighboring guide paths, however, each associated with separate guide grooves, are formed by an individual insert.

 This embodiment also allows relatively economical manufacture of the inserts.

In the following, the invention will be explained in more detail, with reference to embodiments shown in the accompanying drawings, which show:
Fig. 1 a cross section of a joint part
exterior, in which separate inserts
for each guide path, are fixed by
compression in the envelope.

Fig. 2 an outer joint part in which
two neighboring guide paths, associated
however, each has guide grooves
distinct, are formed by an insert
individual.

Fig. 3 a cross section of a joint part
in which each groove of
guidance is achieved by an individual insert.

Fig. 4 a longitudinal section of the joint part
exterior according to FIG. 3, in which the
axial length of the inserts is less than
the axial length of the envelope.

Fig. 5 is a front view of a joint in which the
rollers shrink radially towards
the interior following a curve, the inserts
being adapted and forming each of the paths of
guide associated with two guide grooves
separate.

Fig. 5a a longitudinal section of the joint according to the
figure 5.

Fig. 6 a front view of a part of the seal
exterior showing the layout of two
opposing forming jaws, which have
different bearing surfaces.

Fig. 7 a front view of a part of the seal
exterior with two forming jaws,
one of which is provided, on surfaces
support, compression lugs against
bare.

Fig. 8 an insert which is provided with a passage at the
center, or notches, to receive
radially deformed material,
the envelope, as an axial stop.

Fig. 8 has a top view corresponding to FIG. 8.

Fig. 9 a front view of part of a seal
outdoor, presenting the complete layout
of six compression jaws, in position of
job.

Fig. 10 a front view of a joint part
exterior, in which the forming is
produced by directed deformations
radially from the inside to the outside.

Fig. 11 a cross section of an envelope
manufactured by spinning.

 In the outer joint part 1 shown in FIG. 1, the inner joint part 2 comprising the tripod pins 3 directed radially outwards and the rollers 4 is indicated symbolically.

 The guide grooves 10 are formed, in FIG. 1, by two inserts 6 separated from each other, and each associated with a guide path 11.

 On the outer periphery of the envelope 5 are provided three recesses 12 distributed uniformly over the periphery, and extending radially inwards as well as over the entire axial length of the envelope. The recesses 12 are made so as to present an effective undercut in the radial direction. They are intended to receive compression pins 15 provided on the bearing surfaces 14a of the forming jaws 13.

 In Figure 2 is shown in cross section, an outer seal portion 1 in which the inserts 8 each form two adjacent guide paths 11, which however do not belong to the same guide groove 10. The inserts 8 are provided with passages 21 in which the material of the casing 5 can penetrate radially, during compression, with a view to stopping the inserts 8 against an axial displacement.

 FIG. 3 shows a cross section of an outer seal part 1, in which the guide grooves 10 are each formed by an individual insert 7.

 FIG. 4 shows a longitudinal section corresponding to FIG. 3, and showing that the inserts 7 have a shorter axial length than the envelope 5.

 Due to the compression operation being carried out by being directed radially inwards, material will be forced back by compression around the axial external surfaces of the inserts 7, thereby stopping these inserts 7 against an axial displacement.

 FIG. 5 shows a section of a joint, in which the contour of the outer roller 4 tapers radially inward following a curve, the inserts 8 being adapted to the exterior contour of the roller 4.

 FIG. 5a shows a longitudinal section of a seal according to FIG. 5. The external seal part 1 is provided, in the case of FIG. 5a, with a connection shaft end 22.

 FIG. 6 shows an outer seal part 1 comprising the inserts 8, as well as two forming jaws 13, which have different bearing surfaces 14a and 14b. On the forming jaw 13 located on the right in FIG. 6, two compression studs 15 are provided, which produce a more uniform compression of the material of the envelope 5, in the area of the inserts 8, by coming to engage in the recesses 9.

 FIG. 7 is similar to FIG. 6, the compression studs 15, however, having an undercut by engaging in recesses 12 in the undercut, of the casing 5. In this case, the forming jaws 13 are introduced axially into the envelope 5.

 FIG. 8 shows the support insert 8 which is assigned to two adjacent guide tracks 11, however associated with separate guide grooves 10.

 FIG. 8a shows the top view of the insert 8 according to FIG. 8. The insert 8 is provided with a slot 21.

 In FIGS. 8 and 8a are also shown notches 23 which also serve for the axial anchoring of the inserts 6, 7 or 8.

 FIG. 9 shows the arrangement of six forming jaws 13 around the envelope 5. A forming mandrel 20 is arranged inside the outer seal part 1 to be manufactured.

 FIG. 10 shows a method according to which the stress by external forces for fixing the inserts 8 in the casing 5 takes place radially from the inside to the outside.

 In the case of FIG. 10, the connection obtained by compression, between the inserts 6, 7, 8 and the envelope 5, is produced by a deformation directed radially towards the outside of determined zones of the envelope 5. In this which relates to the method according to FIG. 10, a conical compression mandrel 17 is used, which can be moved axially, and by means of which compression jaws 18 are moved radially outwards. These compression jaws 18 act on ribs 16 provided on the casing 5, which undergo a backflow and produce the fixing of the inserts 6, 7, 8. The force acting radially outwards is absorbed by forming jaws 13, which for their part are supported by a support ring 19.

 FIG. 11 shows an undeformed envelope blank 5 obtained by spinning.

Claims (11)

CLAIMS.  1. Method for manufacturing an outer seal part for a tripod seal, comprising three guide grooves extending parallel to the axis and each having two guide paths, in which are guided roller assemblies each composed of '' an inner roller and an outer roller mounted to rotate on the inner roller, and each arranged on a trunnion oriented radially relative to the axis of the joint and being in correspondence with the guide grooves, the guide grooves being formed , at least in the region of the guide tracks which are associated with them, by inserts of a hardened material, characterized in that the inserts (6, 7, 8), during a first step, are inserted in an envelope (5) correspondingly pre-shaped, made of an easily deformable material, and having substantially a hexagonal shape configuration as to its external shape, in that during a second step, a forming mandrel (20) corresponding to its external dimensions, to the internal contour of the external seal part (1), to be produced, is introduced inside the composite assembly consisting of the inserts (6, 7, 8) and of the envelope (5), and in that during a third step, the envelope (5) is deformed radially inwards by at least partially enclosing the inserts (6, 7, 8 ), the inserts (6, 7, 8) being held in a defined position, relative to each other, by the forming mandrel (20).  2. Method according to claim 1, characterized in that the force intended for the inwardly directed deformation of the envelope (5) is applied by at least three forming jaws (13) capable of carrying out a work advance directed radially inwards and acting between the guide tracks (11).  3. Method according to claim 1, characterized in that the force intended for the deformation directed radially inwards is applied by six forming jaws (13) capable of carrying out a radial working advance, and in that one puts using two sets of forming jaws (13) having different bearing surfaces (14a, 14b), urging the casing (5), the bearing jaws (13) having bearing surfaces (14a, 14b) different being arranged alternately.  4. Method according to any one of claims 1 & 3, characterized in that recesses (12) on the envelope (5), which have an undercut in the radial direction, are biased by compression pins (15) of corresponding shape, arranged on the bearing surfaces (14a), the compression studs (15) being introduced axially into the recesses (12).  5. Method according to any one of claims 1 to 4, characterized in that the envelope (5) pre-shaped is manufactured by spinning.  6. Method according to any one of claims 1 to 5, characterized in that the inserts (6, 7, 8) are provided with notches or notches (21, 23) oriented perpendicular to the axis of the joint and intended for axial fixing.  7. Method for manufacturing an outer seal part, in particular for a tripod seal, comprising three guide grooves extending parallel to the axis and each having two guide paths, in which are assembled roller compound assemblies each of an inner roller and an outer roller mounted to rotate on the inner roller, and each arranged on a trunnion oriented radially with respect to the axis of the seal and being in correspondence with the guide grooves, the guide grooves being formed, at least in the region of the guide tracks which are associated therewith, by inserts of hardened material, characterized in that the connection of the inserts (6, 7 or 8) is generated by a deformation directed radially towards the exterior, ribs (16) disposed between the guide grooves (10), the compression pressure directed radially outward being applied by a conical compression mandrel e (17), biased by an external force, displaced axially inwards from the outer joint part and acting on compression jaws (18) which can move radially, and in that the compression pressure acting radially towards the outside , is absorbed by forming jaws (13) resting on a support ring (19).  8. Outer seal part produced according to the process according to any one of Claims 1 to 7, characterized in that the casing (5) is made of an aluminum alloy.  9. outer seal part according to claim 8, characterized in that the guide grooves (10) are each formed by an individual insert (7).  10. outer seal part according to claim 8, characterized in that the guide grooves (10) are formed by inserts (6) separated, each associated with a guide path (11).  11. Outer seal part according to claim 8, characterized in that two neighboring guide paths (11), however associated, each, with separate guide grooves (10), are formed by an individual insert (8).