Device for attaching a roller bearing in a casing of a motor vehicle and powertrain

Abstract

The invention relates to a device (100) for attaching a roller bearing (10) in a casing (1) of a motor vehicle, the roller bearing (10) being arranged to be mounted around a rotary shaft (20), the attachment device (100) comprising: • - a split ring (110) suitable for being mounted on an outer ring (13) of the roller bearing (10) and comprising a male outer surface (112), at least a portion of which has a frustoconical shape; • - an insert (120) suitable for being attached to an inner surface of the casing (1) and comprising a female inner surface (122), at least a portion of which has a frustoconical shape nested in the male outer surface (112) of the split ring (110), the portion of the male outer surface (112) and the portion of the female inner surface (122) having matching shapes.

Description

DESCRIPTION TITLE OF THE INVENTION: DEVICE FOR FIXING A BEARING IN A CASING OF A MOTOR VEHICLE AND POWERTRAIN TECHNICAL FIELD OF THE INVENTION [1] The present invention relates generally to the mounting of rotating moving parts in casings. [2] It relates more specifically here to a device for fixing a bearing in a casing of a motor vehicle. [3] It also relates to a powertrain of a motor vehicle comprising a device for fixing a bearing in a casing of an engine of said vehicle. STATE OF THE ART [4] A thermal, electric or hybrid powertrain always has rotating shafts mounted freely in casings. For this assembly, it is known to use ball bearings, needle bearings, roller bearings, etc. [5] Such a bearing receives numerous forces, both axial and radial. Therefore, it is necessary that the bearing is mounted without play both on the shaft and in the housing in order to avoid the appearance of wear and degradation phenomena, known under the English name of micro-fretching, which induce noise and premature damage to the housing and the bearing. [6] To overcome this problem, it is known to shrink-fit the inner ring of the bearing onto the motor shaft. [7] However, it is often impossible to fit the outer ring of the bearing in a fretted manner in the housing due to difficult access to the location of this ring. In addition, heating the housing risks causing irreversible deformations leading to the generation of micro-fretting. PRESENTATION OF THE INVENTION [8] In order to overcome the aforementioned drawback of the state of the art, the present invention proposes a device for fixing a bearing in a casing of a motor vehicle, said bearing being arranged to be mounted around a rotating shaft, the fixing device comprising: - a split ring adapted to be mounted on an outer ring of the bearing and comprising a male outer surface of which at least one part has a frustoconical shape, - an insert adapted to be fixed to an inner surface of the casing and comprising a female inner surface of which at least a part has a frustoconical shape fitted into the male outer surface of the split ring, said part of the male outer surface and said part of the female inner surface being of complementary shapes. [9] During assembly, the insert is in practice fixed to the housing, while the split ring is attached to the external face of the outer ring of the bearing.

[0010] The truncated cone shape of the split ring portion and the insert portion allows the split ring and bearing assembly to slide into the housing with limited assembly force, making it easy to mount the bearing in the housing. These complementary truncated cone shapes ensure that there is no play between the two parts by pushing the split ring against the insert. This design therefore provides easier and more controlled assembly.

[0011] Such a design can also allow natural centering of the split ring and bearing assembly in the housing during assembly, so as to obtain minimal radial and axial clearances between the bearing and the housing.

[0012] In addition, the complementarity of the insert and the split ring allows the bearing to be held tightly in the housing after assembly. This design ensures zero radial clearance after assembly between the bearing and the housing, improving the service life of the housing and the bearing.

[0013] Other advantageous and non-limiting characteristics of the fixing device according to the invention, taken individually or in all technically possible combinations.

[0014] In one embodiment, the insert and the split ring are made of materials having similar coefficients of expansion.

[0015] In one embodiment, the fixing device comprises a retaining plate secured to the outer ring of the bearing, and at least one means for fixing the retaining plate against the casing such as a fixing screw.

[0016] In one embodiment, the retaining plate is shrink-fitted to the outer ring of the bearing or the retaining plate and the outer ring of the bearing are made as a single piece.

[0017] In one embodiment, the frustoconical portion of the outer surface of the split ring tapers in a direction facing away from the retaining plate.

[0018] In one embodiment, there is further provided a retaining nut adapted to be screwed into a threaded portion of an inner surface of the split ring and to bear against the outer ring in order to maintain the split ring relative to the casing, said retaining nut preferably being adapted to engage in a recessed housing in the outer ring.

[0019] In this embodiment, the retaining nut may be included in the fastener or be an external part of the fastener.

[0020] In one embodiment, the retaining nut comprises at least one notch and in which a washer is provided placed between the bearing and the retaining nut, which has a tab adapted to be folded into said notch to lock the retaining nut.

[0021] In one embodiment, the frustoconical portion of the outer surface of the split ring tapers in a direction facing the retaining plate.

[0022] In one embodiment, a clearance is provided between the split ring and the retaining plate.

[0023] In one embodiment, the fixing device further comprising a centering cone positioned in the free space and adapted to be mounted around the bearing, said centering cone having an outer surface having a frustoconical shape complementary to that of a portion of the housing, said outer surface and the frustoconical-shaped portion of the outer surface of the split ring tapering in opposite directions.

[0024] In one embodiment, the centering cone and the outer ring of the bearing are made of a single piece.

[0025] In one embodiment, the fastening device further comprises a locking wall having an opening for receiving the at least one fastening means used to secure the retaining plate to the housing and a portion which bears against one end of the split ring.

[0026] The invention also provides a powertrain comprising an engine which comprises a casing and a shaft mounted to rotate freely in the casing (by means of at least one bearing, characterized in that it comprises a fixing device as described above for fixing the bearing in the casing.

[0027] Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive. DETAILED DESCRIPTION OF THE INVENTION

[0028] The description which follows with reference to the appended drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

[0029] On the attached drawings:

[0030] [Fig. 1] is an axial section of a fixing device according to a first embodiment of the invention;

[0031] [Fig. 2] is a schematic perspective representation of a split ring together with a retaining nut and washer of the fastening device shown in Fig. 1;

[0032] [Fig. 3] is a schematic perspective representation of a housing in which the fixing device of Fig. 1 is fixed;

[0033] [Fig. 4] is an axial half-section of the fixing device according to a second embodiment of the invention;

[0034] [Fig. 5] is a half cross-section of an alternative embodiment of the fixing device of Fig. 4.

[0035] As a preliminary point, it will be noted that the identical or similar elements of the different variant embodiments of the invention shown in the different figures will, as far as possible, be referenced by the same reference signs and will not be described each time.

[0036] In Figures 1 and 4, two embodiments of a fixing device 100; 200 are shown for fixing a bearing 10 in a casing 1 of a motor vehicle powertrain.

[0037] In the present invention, the bearing 10 is mounted around a rotating shaft 20 of this powertrain. This can be any shaft of this group, for example a clutch shaft, a gearbox shaft, etc. Here, it will be considered that it is a motor shaft of an electric machine.

[0038] In this example, the bearing 10 comprises an inner ring 11 mounted around the rotating shaft 20, balls 12 and an outer ring 13. This outer ring 13 here has a diameter of the order of 90 mm.

[0039] The inner ring 11 is for example mounted shrink-fit on the rotating shaft 20.

[0040] The outer ring 13 is, on the other hand, mounted in the casing not directly, but via the aforementioned fixing device 100; 200.

[0041] This fixing device 100; 200 comprises for this purpose a split ring 110 mounted on the outer ring 13 of the bearing 10 and an insert 120 fixed in an opening 4 located in a wall 2 of the casing 1. These two elements 110, 120 are therefore interposed between the casing 1 and the bearing 10.

[0042] Here, as clearly shown in Figure 2, the split ring 110 has an annular shape of revolution around a central axis A1, except that it has an axial slot 111.

[0043] It should be noted in this regard that in the remainder of this presentation, the term axial will be used to designate elements which extend parallel to the central axis A1 while the terms transverse and radial will designate elements which extend orthogonally to this axis.

[0044] This split ring 110 has an axial length greater than its thickness radial.

[0045] The slot 110 in this example cuts the split ring 110 over its entire length and over its entire thickness.

[0046] The split ring 110 has an outer surface 112, called male, having a part 113 of truncated cone shape of revolution around the central axis A1. In the first embodiment, this part 113 of the outer surface 112 of the split ring 110 is extended, at its left end, by a part 114 of cylindrical shape of revolution around the central axis A1.

[0047] On this subject, it will be specified in the following that the terms right and left will be used taking into account figures 1, 4 and 5, the left part of an element being in practice turned towards the inside of the casing and the right part towards the outside.

[0048] Thus, the split ring 110 has a base S1 and a top S2. From the base S1 to the top S2, the truncated cone-shaped part 113 has a convergent shape which tapers in a first direction, towards the left in Figure 1 (hereinafter called the assembly direction M1) and towards the right in Figure 4 (hereinafter called the disassembly direction M2).

[0049] The split ring 110 has an inner surface 115 which is here perfectly cylindrical of revolution. At rest, its diameter is slightly smaller than that of the outer surface of the outer ring 13 of the bearing 10. Thus the split ring 110 must be slightly elastically deformed to be mounted on this outer ring 13.

[0050] The insert 120 is integral with the casing 1 in the sense that it is fixed therein in a non-removable manner. It can thus, for example, be integrated into the casing 1 during the molding of the latter. Alternatively, it could be envisaged that it be shrunk there.

[0051] This insert 120 has an annular shape of revolution around the central axis A1.

[0052] It has an axial length greater than its radial thickness.

[0053] It comprises an inner surface 122, called female, which is adapted to accommodate the outer surface 112 male of the split ring 110. The inner female surface 122 of the insert 120 has for this purpose a frustoconical shape of revolution around the central axis A1.

[0054] Thus, the insert 120 has a base S4 and a truncated apex S3. From the base S4 to the truncated apex S3, its outer surface 122 has a convergent shape which tapers in a second direction, towards the right in Figure 1 and towards the left in Figure 4.

[0055] In this way, the truncated cone-shaped portion 113 of the split ring 110 is tapered in a direction opposite to the outer face of the insert 120. Such features allow the split ring 110 to slide in the insert 120 when the bearing 10 is mounted in the housing 1 in the mounting direction M1. Thus, such a shape makes it easier to mount the bearing 10 in the housing 1 in the mounting direction M1.

[0056] In these embodiments, the male outer surface 112 of the split ring 110 and the female inner surface 122 of the insert 120 are of complementary shapes. In other words, the angles defined at the truncated vertices of the frustoconical shapes are identical (the truncated vertex of the split ring 110 being positioned at the start of the portion 114 of the cylindrical outer surface 112). Here in particular, the inner surface 122 of the insert 120 is complementary to the frustoconical portion 113 of the inner surface 112 of the split ring 110. Thus, thanks to the complementarity of the frustoconical portions 113, 123, the mounting of the bearing 10 in the housing 1 is facilitated while ensuring tight holding without play of the bearing 10 in the housing 1 after mounting.Indeed, the radial forces at the level of the outer surface 112 of the split ring 110 and the inner surface 122 of the insert 120 make it possible to keep the bearing 10 tight and without play in the housing 1. In addition, the complementarity of these parts allows easy centering of the bearing 10 in the housing 1 during assembly.

[0057] The insert 120 is preferably made of a different material than that of the housing 1. Typically, the housing 1 is made of aluminum while the insert 120 is made of cast iron, for example gray cast iron (for example laminar GL type). The material of the insert 120 gives it sliding and vibration absorption properties that are ideal for mounting the bearing 10. The split ring 110 is made of a material such as cast iron or steel.

[0058] Although in this example the insert 120 and the split ring 110 may be made of different materials, the materials of the insert 120 and the split ring 110 have similar coefficients of expansion to within 10%.

[0059] Such an arrangement helps to dampen vibrations that may be induced when the engine is running, which improves the mechanical strength of the insert / split ring connection.

[0060] In the present disclosure, coefficient of expansion means a coefficient of thermal expansion which corresponds to the ability of a material subjected to a variation in temperature to expand. Typically, the coefficient of thermal expansion measures the fractional change in length per degree change in temperature at a constant pressure and is expressed in K' 1 .

[0061] It is understood that when the outer ring 13 of the bearing 10 is mounted in the housing 1 via the split ring 110 and the insert 120, there is a risk that these two elements will move apart axially, due to the sliding of the split ring 110 on the insert 120.

[0062] To avoid this, the fixing device 100; 200 also comprises a holding plate 130 secured to the outer ring 13 of the bearing 10. This holding plate 130 is, in this example, mounted shrunk on a right end of the outer ring 13 of the bearing 10. Alternatively, it could come formed with it.

[0063] This holding plate 130 is adapted to be applied against the wall 2 of the casing 1, the one in which the opening for receiving the bearing 10 is provided. It is in particular here provided to come into abutment against the right face of the wall 2 of the casing 1 to block the bearing ring 10 in the casing 1 when the bearing 10 is engaged in the casing 1.

[0064] For this, the retaining plate 130 projects radially outwards relative to the central axis A1 of the bearing 10 which coincides with the central axis of the motor shaft 20. The retaining plate 130 preferably extends along a plane orthogonal to the central axis A1 of the bearing 10.

[0065] In the first embodiment illustrated in Figures 1 to 3, the retaining plate 130 is located on the side of the base S1 of the split ring 110. In other words, the frustoconical portion 113 of the outer surface 112 of the split ring 110 tapers in a direction facing away from the retaining plate 130.

[0066] Thus, when mounting the bearing 10 in the housing 1, the split ring 110 and bearing 10 assembly is assembled and then mounted together in the housing 1 in the mounting direction M1. The frustoconical portion 113 of the male outer surface 112 of the split ring 110 then comes into contact with the frustoconical portion of the female inner surface 122 of the insert 120. The split ring 110 slides on this inner surface 122 of the insert 120 under the mounting force defined along the mounting direction M1 until the retaining plate 130 comes into contact with the wall 2 of the housing 1.

[0067] Such a configuration thus makes it possible to automatically center the bearing 10 in the opening 4 provided in the housing 1 and to axially and radially block the bearing 10 in the housing 1.

[0068] As illustrated in Figure 1, once the bearing is assembled to the housing 1, a free space 30 is formed between the split ring 110 and the retaining plate 130.

[0069] Typically, the split ring 110 may have the following dimensions: approximately 15 mm long, 5 mm wide at the top and an average diameter of approximately 94 mm.

[0070] The free space 30 extends axially over a length of between 0.5 mm and 3 mm. Such a configuration makes it possible to guarantee minimal play after assembly between the split ring 110 and the retaining plate 130.

[0071] In this first embodiment, in order to fix the bearing 10, in particular to avoid removal of the bearing 10 in the disassembly direction M2, the holding plate 130 is provided with at least one hole 131 (here three holes 131) adapted to receive a fixing bolt 150 (see figure 3). For this purpose, the wall 2 of the casing 1 is pierced over its entire thickness by openings for the passage of the screws 151 of these fixing bolts 150. Each fixing bolt 150 comprises a screw 151, one head of which bears against one of the faces of the wall 2 of the casing 1, and a bolt which bears against the retaining plate 130. As illustrated in FIG. 3, three fixing bolts 150 are provided distributed around the central axis A1.

[0072] The fixing bolts 150 make it possible to hold the split ring 110 and bearing 10 assembly in the casing 1 by means of the insert 120 with the assurance of zero radial play between the outer ring 13 of the bearing 10 and the casing 1.

[0073] The inner surface 115 of the split ring 110 illustrated in FIG. 1 has, on its left end side, a threaded portion 116.

[0074] In addition, the fixing device 100 comprises a retaining nut 160 adapted to be screwed into the threaded portion 116 of the inner surface 115 of the split ring 110 and to bear against the outer ring 13 of the bearing 10. The retaining nut 160 makes it possible to guarantee a mechanical connection between the split ring 110 and the bearing 10, which prevents this split ring 110 from escaping towards the retaining plate 130 and therefore improves the retention of the bearing 10 in the housing 1. In the example illustrated in FIG. 3, the threaded portion 116 extends axially over 15 mm and has a pitch, called fine, for example of approximately 0.75 mm.

[0075] Here, the retaining nut 160 is housed in a hollow part of the outer ring 13 of the bearing 10, so as not to increase the axial size of the fixing device 100. For this purpose, the outer ring 13 of the bearing 10 has a housing 14 forming a groove in the outer ring 13 of the bearing 10, which opens towards the left and towards the outside.

[0076] The retaining nut 160 has a free end 161 (opposite the bearing 10) provided with notches 162 regularly distributed around the central axis A1. The notches 162 typically have an axial thickness of between 1 mm and 5 mm, here 3 mm. These notches can be used to screw the retaining nut 160 into the split ring 110 using a suitable tool. They also have another function which will appear later.

[0077] Means are also provided for locking the retaining nut 160, making it possible to prevent the latter from unscrewing under the effect of vibrations of the powertrain. These locking means could be in the form of a locknut, but this solution would be bulky and inconvenient. Here, the fixing device 100 instead comprises a washer 170 adapted to be engaged in the housing 14 of the outer ring 13 of the bearing 10, between an internal wall of the housing 14 of the outer ring 13 and the retaining nut 160.

[0078] The 170 washer is typically made of sheet steel and has an axial thickness of approximately 0.5 mm.

[0079] As illustrated in Figure 2 and Figure 3, the washer 170 has a plastically deformable tab 171. This tab 171 here has a thickness of between 1 mm and 5 mm, for example 3 mm in order to give it sufficient flexibility to be deformed. This tab 171 has a width less than or equal to that of the slot 111, in order to be able to be engaged therein.

[0080] It extends before assembly in the plane of the rest of the washer 170 then is folded at a right angle on the side of the retaining nut 160 (in the position of figure 2). Once the retaining nut 160 has been correctly screwed, its end is folded into a notch 162 of the retaining nut 160 in order to block the rotation of the retaining nut 160. As illustrated in figure 3, the size of the notches 162 is adapted to the size of the tab 171 so that the latter can be blocked in the notches 162 of the retaining nut 160.

[0081] Figure 4 illustrates a second embodiment of a fastening device 200. The fastening device illustrated in Figure 4 comprises a split ring 110, an insert 120 and a holding plate 130 as described in the first embodiment. Thus, only the differences with the first embodiment will be described.

[0082] Unlike the previous embodiment, the fixing device illustrated in FIG. 2 does not include a retaining nut 160 and a washer 170. As a result, the outer ring 13 of the bearing 10 does not have a housing.

[0083] In practice, the main difference compared to the embodiment illustrated in Figure 1 is that in this embodiment, the base S1 of the split ring 110 is turned away from the holding plate 130. In other words, this split ring 110 tapers in the disassembly direction M2. On the contrary, the insert 120 tapers in the assembly direction M1. It is therefore understood that this split ring 110 and the bearing 10 cannot be engaged simultaneously in the opening 4 provided in the wall 2 of the casing 1.

[0084] In practice, the split ring 110 can therefore be fitted onto the outer ring 13 of the bearing 10 after the latter has been fitted into the opening 4 of the wall 2.

[0085] As the insert 120 and the split ring 110 can therefore no longer guarantee centering of the bearing 10 at the time of its mounting in this opening 4, the fixing device 200 illustrated in FIG. 4 comprises a centering cone 210 mounted on the outer ring 13 of the bearing 10.

[0086] The centering cone 210 comprises, in this example, an outer surface 212 which has a truncated cone shape. The shape of this outer surface 212 is complementary to that of a part 3 of the casing 1 which also has a truncated cone shape of inverted shape. The centering cone 210 has a truncated apex S5 oriented opposite the holding plate 130. Such a configuration makes it possible to guarantee a centering the fixing device 200 so as to guarantee zero play of the bearing 10 mounted in the casing 1.

[0087] Indeed, when mounting the bearing 10 in the opening 4 made in the wall 2 of the casing 1, the centering cone 210 will bear against the part 3 of the casing 1, which will automatically ensure the centering of this bearing 10. Then, the split ring 110 can be attached from the left to the outer ring 13 of the bearing 10.

[0088] Once assembled, the centering cone 210 is positioned between the split ring 110 and the holding plate 130. This centering cone 210 is notably positioned in the free space 30 formed between the split ring 110 and the holding plate 130.

[0089] Like the first embodiment, the centering cone 210 preferably does not fill the entire free space 30 so as to maintain a free sub-space 31 (an empty volume) between the holding plate 130 and an end 211 of the centering cone 210 facing the holding plate 130. Similarly, another free sub-space 32 is delimited between the centering cone 210 and the split ring 110. Such sub-spaces make it possible to leave a minimum clearance between the holding plate 130 and the centering cone 210 and between the centering cone 210 and the split ring 110 in order to take into account possible deformations of the materials of the components of the fixing device 200, for example caused by a variation in temperature or mechanical stresses. These spaces thus make it possible to guarantee easy mounting of the bearing 10 in the housing 1.

[0090] In order to dampen vibrations that may be induced when the engine is operating, the centering cone 210 is made of a material that has a coefficient of expansion similar to that of the insert 120. Such an arrangement improves the mechanical strength of the insert / centering cone 210 connection. Typically, the centering cone is made of laminar GL cast iron. Alternatively, steel could be used.

[0091] As in the first embodiment, the retaining plate 130 can be held to the housing 1 by fixing bolts engaging in the housing 1 and the retaining plate 130. However, here, only fixing screws 151 are used. They are then screwed directly into threaded bores of the retaining plate 130.

[0092] In order to prevent axial withdrawal of the split ring 110 to the left, the fixing device 200 further comprises a locking wall 220 positioned between the head of the fixing screws 151 and the casing 1. This locking wall 220 has the shape of an annular and flat washer. It is perforated in order to receive the fixing screw 151.

[0093] This locking wall 220 has an internal diameter greater than the external diameter of the bearing 10, but less than the external diameter of the split ring 110. Such an arrangement therefore makes it possible to hold the split ring 110 in the casing 1, in particular to prevent the split ring 110 from being removed from the casing 1 in the direction of disassembly M2. It will be noted that this locking wall 220 will be put in place after the split ring 110 has been engaged on the bearing 10, when the fixing screws 151 are screwed in.

[0094] The blocking wall 220 is typically made of steel and has an axial thickness of between 3 mm and 5 mm. Typically, the blocking wall 220 illustrated in FIG. 4 has a thickness of 5 mm. Such characteristics make it possible to obtain a blocking wall 220 having sufficient mechanical properties to be stable over time.

[0095] It will also be noted that in the fixing device illustrated in FIG. 4, the holding plate 130 and the outer ring 13 of the bearing 10 are made of a single piece, which facilitates the mounting of the bearing 10 in the housing 1.

[0096] In this embodiment, a pinion 40 of the motor is illustrated bearing against the inner ring 11 of the bearing 10. This pinion is mounted shrink-fitted onto the motor shaft 20 so that this inner ring 11 is here blocked between this pinion 40 and a shoulder formed by the motor shaft 20. It therefore does not itself have to be mounted shrink-fitted onto this motor shaft 20.

[0097] Figure 5 illustrates a variant of the second embodiment of the fixing device 200. In this variant, the fixing device 200 comprises a centering cone 310 which has a shape similar to that of the centering cone 210 illustrated in Figure 4. However, unlike the example illustrated in Figure 4, this centering cone 310 is an integral part of the bearing 10. In other words, the centering cone 310 and the outer ring 13 of the bearing 10 are made of a single piece.

[0098] Accordingly, the fixing device 200 illustrated in Figure 5 is made of even fewer parts than the fixing device 200 illustrated in Figure 4, which further facilitates the mounting of the bearing 10 in the housing 1.

[0099] Of course, it is entirely possible that only the outer ring 13 of the bearing 10 and the centering cone 210 are made of a single piece and that the outer ring 13 of the bearing 10 and the retaining plate 130 form separate pieces.

[0100] As illustrated in Figure 5, the fixing device 200 also comprises a free space 30 formed between the holding plate 130 (here the centering cone 210 of the outer ring 13 of the bearing) and the split ring 110.

Claims

CLAIMS

1. Device (100, 200) for fixing a bearing (10) in a casing (1) of a motor vehicle, said bearing (10) being arranged to be mounted around a rotating shaft (20), the fixing device (100, 200) comprising: - a split ring (110) adapted to be mounted on an outer ring (13) of the bearing (10) and comprising a male outer surface (112) of which at least one part (113) has a frustoconical shape, - an insert (120) adapted to be fixed to an inner surface of the casing (1) and comprising a female inner surface (122) of which at least one part (123) has a frustoconical shape fitted into the male outer surface (112) of the split ring (110), said part of the male outer surface (112) and said part of the female inner surface (122) being of complementary shapes.

2. A fastening device (100, 200) according to claim 1, wherein the insert (120) and the split ring (110) are made of materials having similar coefficients of expansion. [Claim s] Fixing device (100, 200) according to any one of claims 1 to 2, in which the fixing device (100, 200) comprises a retaining plate (130) integral with the outer ring (13) of the bearing (10), and at least one means for fixing the retaining plate (130) against the casing (1) such as a fixing screw (151).

4. A fixing device (100) according to claim 3, wherein the frustoconical portion (113) of the outer surface (112) of the split ring (110) tapers in a direction facing away from the holding plate (130).

5. A fixing device (100) according to claim 4, wherein there is further provided a retaining nut (160) adapted to be screwed into a threaded portion (116) of an inner surface (115) of the split ring (110) and to bear against the outer ring (13) in order to maintain the split ring (110) relative to the housing (1), said retaining nut (160) preferably being adapted to engage in a recessed housing (14) in the outer ring (13).

6. A fixing device (100) according to claim 5, wherein the retaining nut (160) comprises at least one notch (162) and wherein a washer (170) is provided between the bearing (10) and the retaining nut (160), which has a tab (171) adapted to be folded into said notch (162) to lock the retaining nut (160).

7. A fastening device (100, 200) according to claim 3, wherein the frustoconical portion (113) of the outer surface (112) of the split ring (110) tapers in a direction facing the holding plate (130).

8. Fastening device (200) according to claim 7, wherein there is provided a free space (30) between the split ring (110) and the retaining plate (130), the fastening device (200) further comprising a centering cone (210, 310) positioned in the free space (30) and adapted to be mounted around the bearing (10), said centering cone (210, 310) having an outer surface (212) having a frustoconical shape complementary to that of a portion (3) of the housing (1), said outer surface (212) and the frustoconical-shaped portion of the outer surface (112) of the split ring (110) tapering in opposite directions.

9. A fixing device (200) according to claim 8, wherein the centering cone (310) and the outer ring (13) of the bearing (10) are made of a single piece.

10. A fastening device (200) according to any one of claims 8 to 9, wherein it further comprises a locking wall (220) having an opening for receiving the at least one fastening means used to secure the retaining plate (130) to the casing (1) and a portion which bears against one end of the split ring (110).

11. Powertrain comprising an engine which comprises a casing (1) and a shaft (20) mounted to rotate freely in the casing (1) by means of at least one bearing (10), characterized in that it comprises a fixing device (100, 200) according to any one of claims 1 to 10 for fixing the bearing (10) in the casing (1).

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