FR2910057A1 - AXIAL BUFFER OF TURBOCHARGER - Google Patents

Abstract

Axial turbocharger abutment, comprising a functional central portion (1) having areas of axial contact (2a-2e), and a peripheral fixing portion (3) integral with the functional central portion (1). The central portion (1) has a central core (5) of a first material, forming said axial contact areas (2a-2e). The peripheral fixing part (3) comprises a peripheral body (6) in a second material different from the first material. The central core (5) is attached and fixed in the peripheral body (6).

Description

The present invention relates to turbochargers, and more

  particularly the axial stops of turbochargers. In general, an axial turbocharger abutment comprises: a functional central part made of a first material, having areas of axial contact, a peripheral fixing part made of the same material, integral with the functional central part. Conventionally, the turbocharger axial stops are made in one piece using various brass grades. The material of the axial abutment is chosen so that the coefficient of friction of the functional central part is adapted to the high rotational speeds of the turbocharger rotors. For example, sintered iron, free-cutting brass and brass to aluminum have been used. As the price of raw materials is constantly increasing, the realization of axial thrust turbocharger is proving more and more expensive. A first problem proposed by the invention is to significantly reduce the manufacturing costs of a reliable axial thrust of a turbocharger, without degrading its functions and technical characteristics. In another aspect, the invention seeks to manufacture reliable axial turbocharger abutments using a quick, inexpensive, easy process and requiring no heavy investment in production means. To achieve these objects as well as others, the invention provides an axial turbocharger abutment, comprising: - a functional central portion of a first material with a suitable coefficient of friction and forming sliding axial contact zones, - a peripheral portion fastening, integral with the functional central part, and suitable for fixing in a turbocharger body, according to the invention: - the central part forming said axial contact areas sliding in a first material is part of or consists of a central core, the peripheral attachment portion comprises a peripheral body in a second material different from the first material, the central core is attached and fixed in the peripheral body. In an axial thrust of a turbocharger, this significantly limits the amount of first material with a suitable coefficient of friction, which is expensive, without degrading the functions and technical characteristics of the axial abutment. The functional central portion remains in an expensive material, in particular in its areas of axial contact, while the peripheral portion, which is not subject to sliding contacts, can be made of a different material which is less expensive, presenting only the mechanical properties necessary for the attachment of the axial stop in a turbocharger body. According to a first embodiment of the invention, it can be envisaged that the fixing of the central core in the peripheral body is carried out by crimping. Such a fixing method is reliable, inexpensive, easy and quick to perform. In addition, such a process does not require any heavy investment in particular production means. Preferably, the crimping can be carried out essentially by deformation of the peripheral body, the central core being little or not deformed. This avoids inducing stresses and deformations in the functional central part, whose integrity is critical to ensure proper operation of the axial abutment. Any excessive deformation and stress could indeed induce cracks in the material of the central core, or vibrations, which would be unacceptable and dangerous for the proper operation of the turbocharger. Advantageously, it can be provided that: the abutment comprises an annular groove, around the zones of axial contact, the crimping of the central core in the peripheral body is carried out in line with the annular groove. The annular groove of the axial abutment, annular groove which serves to evacuate the lubricating oil from the zones of axial contact with the abutment is thus made cheaply. In addition, the realization of the annular groove is performed without weakening or constraining the central core, and without requiring a lost extra thickness of the peripheral body. The crimping is then located in the annular groove, an area which is set back from the functional surfaces (the axial contact areas) of the functional central part. It is thus certain that crimping will not cause any fault in the behavior of the abutment during its use, since the crimping zone is not likely to inadvertently induce undesirable support on any part or part of the turbocharger. Preferably, the central core may comprise: a peripheral cylindrical peripheral portion having a peripheral lateral surface, developing along the axis of the abutment between an upper face and an opposite lower face, on at least a portion of its periphery, a chamfer between the upper face and the peripheral lateral surface, and a chamfer between the lower face and the peripheral lateral surface. The central core thus has a simple and inexpensive form to achieve by known manufacturing processes and widespread in the industry. Advantageously, it can be provided that the chamfers which connect the upper face and the peripheral lateral surface on the one hand and the lower face and the peripheral lateral surface on the other hand have angles of between approximately 30 degrees and approximately 60 degrees. The choice of the chamfer angles is made as a function of the axial forces which the axial abutment must receive, and as a function of the rotational torques induced on the abutment at its functional central part, on the other hand, during 'use. According to a second embodiment of the invention, provision can be made for the peripheral body to comprise two flanges that are attached and fixed against one another and against the central core, partially overlapping on either side of the body. central core. There is thus an inexpensive fixing method, easy and quick to implement, and requiring little investment in means of production. According to another aspect, the invention proposes a turbocharger 25 comprising an axial abutment as defined above. In another aspect, there is provided a method of manufacturing an axial thrust turbocharger according to the invention. This manufacturing method comprises the following successive steps: a) providing a central portion of a first material, forming part of or consisting of a central core, b) providing a peripheral portion in a second material, forming the peripheral body, c ) report and fix the central nucleus in the peripheral body. To achieve the first embodiment of axial stop according to the invention, it can be provided that during step c), the central core is fixed in the peripheral body by crimping. In order to carry out the second embodiment of axial stop according to the invention, provision may be made for: the peripheral body comprises two flanges; during step c), the two flanges are fixed; against the other and against the central core, partially covering the central core on either side thereof to immobilize the central core relative to the flanges. Other objects, features and advantages of the present invention will emerge from the following description of particular embodiments, with reference to the accompanying figures, in which: FIG. 1 is a view from above of an axial abutment according to a first embodiment of the invention; - Figure 2 is a side view in section of the axial stop of Figure 1; FIG. 3 is a sectional side view of an axial abutment variant of the first embodiment shown in FIGS. 1 and 2; Figures 4 and 5 are side sectional views illustrating the method of manufacturing the axial stops of Figures 1 to 3; FIG. 6 is a view from above of a second embodiment of an axial stop according to the invention; Figures 7 to 9 are sectional side views illustrating the method of manufacturing the axial stop of Figure 6; and - Figure 10 is a sectional view of a turbocharger. FIG. 10 is a sectional view of a turbocharger provided with an axial abutment 100 of the prior art, of axis III-III and held in place by a screw 101. The axial abutment 100 of the prior art comprises an inlet pocket 102, supplied with oil by the oil line circuit 103. The immobilized stop 100 comprises a functional central portion 104 subjected to contact with rotating elements integral with the shaft 105 on which the turbines are mounted. 106 and 107. Depending on the operating phases of the turbocharger (acceleration or deceleration), the turbines 106 and 107 induce axis axial forces III-III which are taken up by the axial abutment 100 in one direction and the other. The contact of the functional central portion 104 with the rotating elements is lubricated by oil supplied from the inlet pocket 102 in the vicinity of the functional central portion 104 by an internal feed pipe 108. As can be seen, the axial abutment 100 is in one piece in one and the same material.

  Figures 1 and 6 show a top view of two embodiments of axial stops according to the invention. Each axial abutment comprises: a functional central portion 1 in a first material, having areas of axial contact 2a to 2e on the visible face, a peripheral fixing portion 3, integral with the functional central portion 1 .

The axial contact areas 2a-2e are lubricated with oil, fed from an inlet pocket 11 via an internal supply pipe 12. The functional central part 1 comprises, between the axial contact zones 2a-2e. , oil supply pockets 13a-13e from which "overflows" the oil to lubricate the axial contact areas 2a-2e. The excess oil is then collected, at the periphery of the axial contact zones 2a-2e, in an annular groove 8 which channels this excess oil to a weir 14. The peripheral fixing portion 3 comprises in particular two fixing holes 4a and 4b for fixing the stop in the turbocharger body, but the number, shape and positioning of these lights are only illustrative. In Figures 1 and 6, only the upper faces of the axial stops are apparent. Axial abutments, however, have a lower face substantially identical to their upper face, having axial contact zones, oil supply pockets, an annular groove and a spillway. For example, FIGS. 2, 3 and 9 show oil supply pockets 13'b, 13'c or 13'd. There is shown in Figure 3 a spillway 14 '. As can be seen more particularly in FIGS. 2 and 9, the functional central portion 1 comprises a central core 5 forming said axial contact zones: FIG. 2 distinguishes the axial contact zones 2b, 2c and 2d on the upper face. and the areas of axial contact 2'b, 2'c and 2'd on the underside. Similarly, in FIG. 9, the areas of axial contact 2b, 2c, 2d and 2e on the upper face and the areas of axial contact 2'b, 2'c, 2'd and 2'e on the lower face are distinguished. The peripheral fixing portion 3 comprises a peripheral body 6 in a second material different from the first material of the functional central portion 1. The central core 5 is attached and fixed in the peripheral body 6. It can be clearly seen in FIGS. 9 that the majority of material is constituted by the peripheral body 6 and that a lesser part of material is constituted by the functional central part 1. The material of the functional central part 1 being the most expensive, it is limited significant amount of material present in the axial abutment.

However, the functions and technical characteristics of the axial abutment are not degraded, since the functional central part 1 remains constituted by the first material usually used and chosen for its appropriate coefficient of friction and its excellent resistance to friction. wear.

Figure 2 is a sectional side view of axis A-A of the axial abutment of Figure 1, i.e., of a first embodiment of the invention. In this particular embodiment of the invention, the fixing of the central core 5 in the peripheral body 6 is performed by annular crimps 7a and 7b.

The crimps 7a and 7b may be continuous or discontinuous depending on the periphery of the central core 5. In the embodiment of FIG. 1, the crimps 7a and 7b are continuous. It can be seen from FIGS. 2, 4 and 5 that the crimps 7a and 7b are made essentially by deformation of the peripheral body 6, the central core 5 being little or not deformed. Indeed, it is observed in FIGS. 4 and 5 that, before crimping, the central core 5 has its definitive form of FIG. 2, that is to say that it comprises external dimensions substantially identical to the external shape of the central core 5 in Figure 2 which is a sectional view of an axial abutment after completion of the crimps 7a and 7b.

The fact of deforming only very little (if at all) the central core 5 avoids the induction of stresses and deformations in the functional central portion 1 of the axial abutment, stresses and deformations that could cause cracking of the part functional center 1. The axial stop would then no longer be able to fulfill its technical functions when used in a turbocharger. After manufacture, it is observed in Figures 1 and 2 that the axial abutment comprises annular grooves 8 and 8 ', around the axial contact areas such as zones 2a-2e. The annular grooves 8 and 8 'are created by the making of the crimps 7a and 7b for fixing the central core 5 in the peripheral body 6. The crimps 7a and 7b of the central core 5 in the peripheral body 6 are thus made to the right annular grooves 8 and 8 '. To perform the crimps 7a and 7b, the central core 5 comprises (FIG. 4): a cylindrical annular peripheral portion 9 with a peripheral lateral surface 9a, 35 developing along the axis II of the abutment between an upper face 9b and a face 9c opposite, 2910057 5055FDFP.doc 7 - on at least part of its periphery, a chamfer 10a between the upper face 9b and the peripheral side surface 9a, and a chamfer 10b between the lower face 9c and the peripheral side surface 9a. When fixing the central core 5 in the peripheral body 6, the material of the inner periphery of the peripheral body 6 is deformed by flowing the material of the peripheral body 6 on either side of the chamfers 10a and 10b of the central core 5. In this case, the annular volume of material 7e (indicated in FIG. 5) is fluted in the chamfers 10a and 10b of the central core 5. The crimps 7a and 7b are thus located in the annular grooves 8 and 8 and remain definitely in withdrawal from the functional surfaces (axial contact areas 2a-2e) of the functional central portion 1. It is thus ensured that the crimps 7a and 7b will not cause any undue support on parts or elements of the turbocharger during operation. The chamfers 10a and 10b respectively have angles a and R 15 of between about 30 degrees and about 60 degrees. The values of the angles a and R are chosen so as to ensure, on the one hand, a good resistance of the crimps 7a and 7b to the axis forces 1-I, and, on the other hand, a good resistance to the torques in rotation around the axis 1-1, the forces and torques being induced on the abutment at its functional central portion 1.

If the angles α and R are chosen to be close to 60, the crimps 7a and 7b provide a better hold against the rotational torques induced on the abutment at its functional central portion 1. On the other hand, the holding of the Central core 5 in the peripheral body 6 against axis axial forces 1-1 is lower.

On the other hand, if angles a and 13 are chosen to be equal to 30, a better resistance to axis axial forces 1-1 is obtained for retaining the central core 5 in the peripheral body 6, but we obtain a lower holding of the central core 5 in the peripheral body 6 against the rotational torques induced on the stop at its functional central portion 1.

A good compromise has been achieved by making chamfers 10a and 10b with angles a and 13 of about 45. Although the angles a and f3 have been shown equal in FIGS. 2, 4 and 5, it should be understood that these can differ, depending on the axial forces of axis I-1 applying in one direction and in one another. the other on the turbocharger rotor. Indeed, the axial forces in a turbocharger are different in the axial direction considered, and the angles a and f3 can be selected and optimized independently of one another.

In the embodiment illustrated in FIGS. 2, 4 and 5, the values of the angles a and i are substantially identical In the embodiment illustrated in FIGS. 2, 4 and 5, the central core 5 comprises, on each of its upper 9b and lower 9c faces, an external peripheral annular dl or d2 recess (FIG. 2) The peripheral body 6 comprises an inner periphery 15 with a thickness E1 substantially equal to the thickness E2 separating the upper 9b and lower 9c faces of the central core 5. FIGS. 2, 4 and 5 illustrate the manufacturing process of the abutment of FIG. 1. This method comprises the following successive steps: a) a central part 1 is provided in a first material, forming a central core 5 (Figure 4), b) there is provided a peripheral portion 3 in a second material, forming the peripheral body 6 (Figure 4), c) the central core 5 is reported in the peripheral body 6 (FIG. 5) and the central core 5 is fixed in the peripheral body 6 (FIG. 2). During step c), the central core 5 is fixed in the peripheral body 6 by making the crimps 7a and 7b by deformation of the peripheral body 6, the central core 5 being only very little (or not) deformed.

FIG. 5 shows more particularly that, during the step c) of fixing the central core 5, the material 7e of the inner periphery 15 of the peripheral body 6 is deformed by flowing the annular volume of material 7e of the peripheral body 6 on either side of the chamfers 10a and 10b of the central core 5. Thus, inner peripheral annular recesses d3 and d4 (FIG. 2) are formed on each of the upper 9b and lower 9c faces of the peripheral body 6. internal peripheral annular recesses d3 and d4 correspond to the outer peripheral annular recesses d1 and d2 of the central core 5 to form the annular grooves 8 and 8 'of axial abutment.

FIG. 3 illustrates a variant of the first embodiment of the invention illustrated in FIGS. 1, 2, 4 and 5. In this variant, the central core 5 comprises a cylindrical annular peripheral portion 9 which is larger than in FIGS. , 4 and 5. The central core 5 thus comprises areas of axial contact 2a-2e (represented only in part) of smaller surface since extending radially away from the axis 1-1 by a distance D2 less at the distance D1 of the axial abutment of FIG. 2. The annular grooves 8 and 8 'of the axial abutment of FIG. 3 then have larger dimensions than those of the axial abutment 2910057 5055PDEP.doc 9 of FIG. The dimensions of the peripheral body 6 remain unchanged. It is thus possible to realize several types of axial stop intended for turbochargers for motors of different powers or generating different axial forces on the abutment, each time adapting a particular central core and of suitable dimensions in a peripheral body. 6 of the same shape. The cost of the tooling for producing the peripheral bodies 6 is thus reduced. FIGS. 6 and 9 illustrate an axial abutment according to a second embodiment of the invention. Figure 6 is a top view while Figure 9 is a side sectional view of axis II-II. It is seen more particularly in FIG. 9 that the peripheral body 6 comprises two flanges 6a and 6b that are attached and fixed against each other while partially overlapping on either side of the central core 5. The central core 5 is 15 fixed in rotation relative to the two flanges 6a and 6b. The rotational immobilization of the central core 5 between the two flanges 6a and 6b can be achieved by means of indexing, or by the pressure applied by the flanges 6a and 6b on either side of the central core 5. It can be achieved by however, prefer the indexing solution so as not to induce excessive stresses or deformations in the central core 5 during the assembly of the two flanges 6a and 6b. Again, significantly reduces the amount of expensive material (used for the central core 5) present in the axial stop, without degrading the functions and technical characteristics of the axial stop. The method of manufacturing the abutment shown in FIG. 6 is illustrated by the succession of FIGS. 7, 8 and 9. This manufacturing method comprises the following successive steps: a) a central part 1 is provided in a first material, forming a central core 5 (Figure 7), b) there is provided a peripheral portion 3 in a second material, forming a peripheral body 6, the peripheral body 6 having two flanges 6a and 6b (Figure 7), c) the two flanges are reported 6a and 6b against each other partially covering the central core 5 on either side thereof (Figure 8), the two flanges 6a and 6b are fixed against each other and against the central core 5 and thereby immobilizes in rotation the central core 5 relative to the flanges 6a and 6b (Figure 9). When the two flanges 6a and 6b approach each other, studs 60a and 60b of the flange 6b enter two holes 61a and 61b of the flange 6a, the studs 60a and 60b having a height greater than that of the holes 61a and 61b so that they exceed a height H (Figure 8) when the flanges 6a and 6b are against each other. The immobilization of the two flanges 6a and 6b is then done by deformation of the distal ends 600a and 600b of the pads 60a and 60b in countersinks 610a and 610b holes 61a and 61b. The advantage of using two flanges 6a and 6b is to allow the realization of complicated internal oil supply lines (not shown) extending from the inlet pocket 11 to the central core 5. These internal conduits of complicated oil supply are then performed on the faces 600c 15 and 610c flanges 6a and 6b intended to come into contact with one another. In the embodiments illustrated in FIGS. 1 to 8, the first material of the central core 5 is brass of the CuZn3ISil grade, and the second material of the peripheral body 6 is made of steel of the grade EN10139. Brass CuZn3lSil has the advantage of allowing the roughing of the central core 5 by cutting and stamping, a quick and inexpensive process. In addition, this brass has only traces of lead, or even a zero lead content. This makes it possible to comply with the requirements of car manufacturers who wish to completely eliminate the presence of lead in vehicles.

The steel grade EN10139 for its part has sufficient mechanical characteristics to ensure the fixing of the axial stop in a turbocharger. In addition, this steel grade allows the easy and fast realization of crimps 7a and 7b. The present invention is not limited to the embodiments which have been explicitly described, but includes the various variants and generalizations thereof within the scope of the claims below.

Claims (10)

  Axial thrust of turbocharger, comprising: a functional central part (1) made of a first material with a suitable coefficient of friction and forming zones of axial contact (2a-2e, 2'a-2'e) sliding; fastening peripheral part (3) integral with the functional central part (1) and suitable for fastening in a turbocharger, characterized in that: - the central part (1) forming said axial contact zones (2a-2e, 2'a-2'e) sliding part of or consists of a central core (5), - the peripheral attachment portion (3) comprises a peripheral body (6) in a second material different from the first material, - The central core (5) is attached and fixed in the peripheral body (6). 2 û turbocharger axial stop according to claim 1, characterized in that the fixing of the central core (5) in the peripheral body (6) is formed by crimping (7a, 7b). 3 û axial thrust of turbocharger according to claim 2, characterized in that the crimping (7a, 7b) is formed essentially by deformation of the peripheral body (6), the central core (5) being little or no deformed. 4-axial axial turbocharger according to one of claims 2 or 3, characterized in that: - the abutment comprises an annular groove (8, 8 '), around the axial contact zones (2a-2e, 2'a- 2'e), - the crimping (7a, 7b) of the central core (5) in the peripheral body (6) is made in line with the annular groove (8, 8 '). 5 û turbocharger axial stop according to any one of claims 2 to 4, characterized in that the central core (5) comprises - a cylindrical annular peripheral portion (9) with peripheral lateral surface (9a), developing according to the axis (II) of the abutment between an upper face (9b) and an opposite lower face (9c), - on at least part of its periphery, a chamfer (10a) between the upper face (9b) and the lateral surface peripheral (9a), and a chamfer (10b) between the lower face (9c) and the peripheral lateral surface (9a). 6-axial axial turbocharger according to claim 5, characterized in that the chamfers (10a, 10b) which connect the upper face (9b) and the peripheral lateral surface (9a) on the one hand and the lower face (9c) and the peripheral side surface (9a) on the other hand have angles (a, (3) of between about 30 degrees and about 60 degrees. Axial thrust of a turbocharger according to claim 1, characterized in that the peripheral body (6) comprises two flanges (6a, 6b) attached and fixed against each other and against the central core (5), partially overlapping on both sides of the central core (5). 8-axial axial turbocharger according to any one of claims 1 to 7, characterized in that: - the first material of the central core (5) is brass of the grade CuZn3l Sil, 10 - the second material of the peripheral body ( 6) is made of steel of the EN10139 grade. 9 - turbocharger characterized in that it comprises an axial stop according to any one of claims 1 to 8. 10 - A method of manufacturing an axial thrust of a turbocharger, characterized in that it comprises the following successive steps: a) a central portion (1) is provided in a first material, forming part of or consisting of a core central (5), b) there is provided a peripheral portion (3) in a second material, forming the peripheral body (6), c) is reported and fixed the central core (5) in the peripheral body (6). Method according to claim 10, characterized in that during step c) the central core (5) is fixed in the peripheral body (6) by crimping (7a, 7b). 12 ù A method according to claim 11, characterized in that the crimping (7a, 7b) performed in step c) is performed essentially by deformation of the peripheral body (6), the central core (5) remaining little or no deformed . 13 - Method according to one of claims 10 to 12, characterized in that: the central core (5) comprises a cylindrical annular peripheral portion (9) with peripheral lateral surface (9a), developing along the axis (l- 1) of the abutment between an opposite upper face (9b) and a lower face (9c), - the central core (5) comprises chamfers (10a, 10b), on at least part of its periphery, between its face, respectively. upper part (9b) and its peripheral lateral surface (9a) on the one hand and between its lower face (9c) and its peripheral lateral surface (9a) on the other hand, during step c ) of fixation, deforming the material of the inner periphery (15) of the peripheral body (6) by flowing the material (7e) of the peripheral body (6) on either side of the chamfers (10a, 10b) of the core central (5). 14 - The method of claim 13, characterized in that: - the central core (5) further comprises, on each of its upper (9b) and lower (9c) faces, an outer peripheral annular recess (dl, d2) the peripheral body (6) comprises an inner periphery (15) with a thickness (El) substantially equal to that (E2) separating the upper (9b) and lower (9c) faces of the central core (5), 10 - at the step c) of fixing the central core (5), deforming the material (7e) of the inner periphery (15) of the peripheral body (6) to produce, on each of the upper (9b) and lower (9c) faces of the peripheral body (6), an inner peripheral annular recess (d3, d4) coming into correspondence with the outer peripheral annular recesses (d1, d2) of the central core (5) to form annular grooves (8, 8 ') of axial stop. 15 - Process according to claim 10, characterized in that: - the peripheral body (6) comprises two flanges (6a, 6b), - during step c), the two flanges (6a, 6b) are fixed 1 against the other and against the central core (5), partially covering the central core (5) on either side thereof to immobilize the central core (5) with respect to the flanges (6a, 6b).