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WELDED FLANGED BEARING

The present invention relates to thrust bearings for rotary shafts, more especially for the shafts of an explosion engine or a rotary machine.

It relates more particularly to a composite thrust bearing for a rotary shaft, formed from a radial bearing with one or two separate axial thrust collars, the composite thrust bearing being made from at least one multilayer or mono etal material.

Solid radial bearings were first of all made which also served as axial thrust collars, machined from solid materials. Then flanged bushes were manufactured and also shouldered bushes, these two types of one piece radial bearings being formed by deforming first of all a monometal then a bimetal strip.

Since such radial bearings had a number of dis¬ advantages (in particular not allowing all types of dimensions, nor the use of different materials for the radial bearing and the thrust collar), bearings were then put on the market made from at least two parts, one forming a radial support and the other an axial support ^' for the rotary shaft. Thus smooth bushing plus at least one thrust flange or straight collar plus at least one thrust collar assemblies were formed.

Such an arrangement having at least two parts offered the advantage that each of the parts could be made from a different material, the one especially appropriate to the parts; for example an aluminum-tin anti-friction material could be used for the bushing and a copper-lead anti¬ friction alloy for the flange.

On the other hand, such bearings made from two or more parts presented a number of drawbacks, particularly

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the need to handle several parts, a risk of error and fitting difficulties. Thus, the positioning of such bearings made form two or more parts in assembly lines using robots gave rise to problems which were very difficult to solve.

So thoughts turned back to monobloc or one piece type parts from the assembly point of view, but formed from at least two different parts so as to keep the advantages of bearings made from at least two parts.

Thus it was proposed to staple or bond the thrust collar to the radial bearing or to weld the radial bearing and the thrust collar together by means of radial welding bosses provided in the inner diameter of the thrust collar and welded to the outer diameter of the radial bearing.

Stapling presents the drawback of being difficult to perform and of requiring an additional amount of material; bonding presents problems or removing the grease from the parts and forming the bonded joint; finally welding by means of radial bosses is only applicable for half flanges welded to half bushings and requires a considerable chamfer between the bearing face and the inner diameter of the half thrust flange so as to avoid the presence of anti-friction material in the steel to steel welding and so as to avoid interference of the thrust collar with the fillet between the thrust face of the shaft and its radial bearing surface.

The object of the present invention is to overcome the above mentioned drawbacks of radial bearings with at least one axial thrust collar by providing a composite thrust bearing for a rotary shaft made from two or more parts (bushing or bearing ring, on the one hand, and thrust collar(s) or bearing flange(s) on the other) by joining these parts together by axially welding, by means of bosses, the radial bearing with the axial thrust collar(s) .

More precisely, the invention consists in providing a

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composite thrust bearing for a rotary shaft from a radial bearing in which the rotating shaft may rotate and at least one axial thrust collar, preventing axial movement of the shaft, characterized in that the radial bearing or the axial thrust collar or one of the axial thrust collars has at least one boss and in that the radial bearing is joined to the axial thrust collar or collars by axial welding along said at least one boss.

The radial bearing and/or the assembly of axial thrust collars may not be completely circular.

As mentioned above, the axial welding boss or bosses may therefore be formed either on the radial bearing, or on the axial thrust collar and even possibly on the bearing and the collar.

The axial welding boss or bosses are obtained by deformation or cutting out of the material forming the radial bearing and/or the axial thrust collar which carries them.

Several axial welding bosses are advantageously provided, more especially 2, 3 or 4 bosses, spaced evenly apart about the periphery of the radial bearing and/or the axial thrust collar.

The angular position of the bosses may also be chosen depending on the functional parameters of the bearing: at 90$ from the joining plane for a half bushing so as to limit to the strict minimum the influence of the deformations due to the connection; inside the oil grooves of the radial bearing or the axial thrust collar so that the connection is set back from the bearing surfaces.

The axial welding boss or bosses may be situated in at least one oil groove of the radial bearing or of the axial thrust collar or collars, so that the face of the axial welding boss or bosses, situated on the bearing surface side, is set back with respect to this bearing surface.

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Advantageously the axial welding boss or bosses, situated on the axial thrust collar or collars, have their welding face which extends from the bearing face of the axial thrust collar or collars inside the bore of the housing of the radial bearing.

The invention may apply not only to complete circular bearings (of _560°), but also to semicircular bearings (180°).

Of course, the radial bearing on the one hand and the axial thrust collar on the other may be made from similar or more advantageously different materials.

In addition, such a construction will allow the radial bearing to be associated with a complex axial thrust collar which can only be manufactured individually (cut-out of a complex shape or stamping of a surface profile) _

The invention will in any case be well understood from the complement of description which follows and the accompanying drawings, which complement and drawings are of course given especially by way of indication.

Figure 1 is a perspective view of the two parts of the composite bearing of the invention before assembly thereof by welding, the axial welding bosses being carried by the axial thrust collar or thrust flange;

Figure 2 illustrates in axial section a composite thrust bearing of the invention formed from a radial half bearing and two half thrust flanges mounted in their housing and supporting a rotating shaft;

Figures 3 , 4 and 5 show schematically three possible positions of the axial welding bosses on a half thrust flange;

Figures 6 and 7 show schematically two possible positions of the axial bosses on an axial thrust collar or thrust flange;

Figure 8 is a section through 8-8 of any one of Figures 3 to 7;

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Figure 9 illustrates partially a half thrust flange or axial thrust collar with its single axial welding boss situated in an oil groove of one of its axial welding bosses;

Figure 10 is a section through 10-10 of Figure 9;

Figures 11, 12 and 13 are variants of Figure 10, depending on whether the material of the lug playing the role of boss for the axial welding is bent, deformed or stamped;

Figure 14 shows in perspective and before assembly a bearing bushing and a bearing thrust collar, the axial welding bosses being this time carried by the bushing;

Figure 15 shows a variant of Figure 14; and

Figure 16, finally, is a section through 16- 6 of Figure 15.

According to the invention and more especially according to that one of its modes of application, as well as those of the embodiments of its different parts to which it seems preference should be given, wishing for example to produce a composite thrust bearing formed by a radial bearing and at least one separate axial thrust collar, the following or similar is the way to set about it.

A composite thrust bearing for a rotary shaft (Figures 1 , 2 and 14) is formed from a bearing rin or bushing 1a or 1b in which the shaft may rotate and an axial thrust collar or at least one flange 2a, 2'a or 2b preventing axial movement of the rotating shaft; in accordance with the invention, bushing lb or collar 2a carries at least one and preferably several bosses 3a or 3b for axial welding thereof. Bushing 1a or 1b is joined to the corresponding collar 2a or 2b by axial welding along said boss or said bosses 3a or 3b (Figure 1 and Figure 14).

In Figure 2 is shown the half bushing 1a and the thrust collars 2a and 2'a forming half flanges welded at 4

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axially along the bosses 3a carried by the half flanges 2a, 2'a. The rotating shaft which can be seen in partial section 6 may rotate in bushing 1a but it is stopped in its movement by the half flanges 2a, 2'a. At 5 is shown the structure supporting the composite thrust bearing 2'a-1a-2a of the invention and at 16 the connecting fillet.

Each of the elementary parts 1a and 2a may be made from any material appropriate to the function played by the part and known by the man skilled in the art. For example the ring or bushing may be made from copper-lead on steel, whereas the flanges or thrust collars 2a, 2 ^! a may be made from aluminum-tin on steel.

Generally several axial welding bosses are advantageously provided, preferably two, three or four bosses, spaced evenly apart in appropriate positions about the internal periphery 2c of the thrust collar (Figures 1 to 13) _. on the lateral face of the radial bearing (Figures 1 to 16).

In the case where the bosses are on. the flange or thrust bearing, several arrangements of bosses 3a are illustrated in Figures 3 to 7: Figures 3 to 5 correspond to a half flange 7, 8 or 9, whereas Figures 6 and 7 correspond to a complete circular collar 10 or 11.

It can be clearly seen in Figures 6 and 7 that the axial bosses 3a are spaced evenly apart about the periphery of the flange or thrust collar 10 or 11.

The axial welding boss or bosses 3 which are on the flange or on the bushing are obtained by deforming the material or cutting it out; they are formed, for example on the steel bearing face of thrust collars 2a, 2'a by being welded to the face of the bearing 1a, as can be seen in Figure 2.

Several embodiments may be practical:

- each boss 3a may be simply a lug cut out in the inner diameter of the half flange or thrust collar 7, 8, 9

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10 or 11 (Figure 8, which is a section through 8-8 of any one of Figures 3 to 7);

- each boss 3a may be positioned in an oil groove of the thrust collar, as illustrated in Figures 9 and 10 (Figure 10 being a section through 10-10 of Figure 9); in this case, with reference 13 still designating the bearing face, the face _Λ θf boss 14 on the friction face side may be set back with respect to the friction face 12 of the thrust collar;

- variants of Figure 10 may also be provided, as illustrated in Figures 11 to 13, the welding face 15 extending beyond the bearing face 13 of the thrust collar; the arrangements of Figure 11 to 13 are obtained by bending the lug cut out without variation of thickness (Figure 11) or by deformation by stamping the lug, with reduction (Figures 12 and 13).

The difficulty consists in designing a boss for axial welding which does not interfere with the fillet 16 of the radial and axial surfaces of the shaft. In the case of Figure 13 _. where the boss is obtained by cutting out, then bending, then stamping a lug situated in an oil groove, the point of face 14 the closest to fillet 16 of the shaft is further removed therefrom than in the other Figures 8, 10, 11 and 12.

In Figures 1 to 13 the invention has been illustrated in the case where the axial welding boss or bosses are provided on the thrust flange or collar.

As mentioned above, axial welding bosses may be provided on the bushing or ring, as illustrated in Figure 14 (bushing 1b carrying axial bosses 3h), the assembly between bushing 1b and flange 2b being also provided by axial welding along bosses 3b.

Though the bosses of Figure 14 are obtained by cutting out, the bosses 3c of Figure 15 are obtained by nipping and flowing the material along the face of the bushing, these bosses 3c allowing axial welding to the

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flange 2c .

Axial welding bosses could also be provided both on the bushing and on the thrust collar, without departing from the spirit of the invention.

In all cases, a composite thrust bearing for a rotary shaft in accordance with the invention, i.e. obtained by axial welding along one or more bosses provided on the radial bearing or on the axial thrust collar, presents numerous advantages and particularly the following advantages:

- semicircular (180°) or circular (360°) bearings can be made;

- the width of the radial bearing can be reduced, so the amount of material to be- used, to a minimum value;

- the composite thrust bearing of the invention does not present the risk of the presence of anti-friction material in the welding zone, which presence is possible in the case of radial welding to bosses in accordance with the prior technique;

- in this bearing there is no interference with the connecting fillet of the rotary shaft because of the depression obtained during formation of the bosses in the embodiments shown in Figures 10 to 13;

- if the welding zone is correctly located at 90 from the joint plane of" a half bushing _r the presence of the half flange has no influence, or has only very little influence on the radial elasticity of the half bushing;

- different anti-friction materials may be used for the thrust flange, on the one hand, and the bushing on the other;

- the axial play may be adjusted with different thrust thickness dimensions for the same radial bearing or conversely different bearing dimensions may be used with the same thrust collar;

- a thrust collar may be used having a convex profile, if desired, for increasing load capacity.

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As is evident and as it follows moreover already from what has gone before, the invention is in no way limited to those of its modes of application and embodiments which have been more especially considered; it embraces, on the contrary, all variants thereof.

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