Engine assembly for a motor vehicle

Abstract

Engine assembly for a motor vehicle. The present invention relates to an engine assembly (1) for a motor vehicle, comprising a crankshaft (2), a housing (3) configured to at least partially house the crankshaft (2) and having at least one receiving bearing for a crankshaft journal (4) of the crankshaft (2), the housing (3) having a groove (10) formed in a lateral face of a wall (9) of the housing contributing to the delimitation of the receiving housing, the engine assembly further comprising at least one axial stop device (11) configured to be housed within the groove (10), characterized in that the axial stop device (11) comprises a first portion (12) and a second portion (13), both configured to be housed within the groove (10), each portion (12, 13) comprising a positioning lug configured to cooperate by complementary shape with a notch formed at one end of the groove (10). (Figure 1)

Description

Title of the invention: Engine assembly for a motor vehicle

[0001] The present invention relates to the field of internal combustion engines for internal combustion vehicles, and more particularly concerns an engine assembly for such an internal combustion engine.

[0002] The engine assembly includes in particular a casing in which pistons are made to move within engine cylinders under the effect of fuel combustion, this casing housing a crankshaft capable of transforming the translational movement of the pistons into a rotational movement of the crankshaft subsequently transmitted to the wheels of the vehicle.

[0003] The crankshaft includes in particular journals, which define the axis of rotation of the crankshaft and which are supported by rotation bearings formed in the engine casing, and crankpins, offset from the journals and which are linked to the pistons.

[0004] The rotational movement of the crankshaft is then transmitted to the vehicle's wheels via gears and secondary shafts of a gearbox. This arrangement results in micro-shocks during gear changes, which can generate micro-displacements of the crankshaft along its axis of rotation. It is therefore known to provide at least one axial stop to block the axial movement of a crankshaft journal in the corresponding receiving bearing formed in the housing, the aim being to ensure that the crankshaft journals remain aligned with the axis of translation of the engine pistons.

[0005] The axial stop is disposed at the receiving bearing of a journal, between a lateral bearing surface of the crankshaft axially delimiting the journal and a wall of the engine casing, in a groove formed for this purpose in said wall.

[0006] This type of thrust bearing is installed manually on an internal combustion engine assembly line. However, several models of internal combustion engines are sometimes assembled on the same line. These different engines may have different characteristics, particularly crankshaft dimensions, including journal diameters, which can vary from one engine to another. Thrust bearings designed for installation on a crankshaft for one model of internal combustion engine are therefore potentially incompatible with other engines, and the installation of an incorrect thrust bearing may occur.The axial stop may then not completely fill the groove because it is too small compared to the aforementioned groove and generate the risk of axial instability of the crankshaft because the journal is not axially blocked in a homogeneous way, or conversely protrude from the groove because it is too large compared to said groove, thus generating the risk of blocking the . assembly of the engine casing parts coming from either side of the crankshaft.

[0007] The present invention makes it possible to avoid such an installation error by proposing an engine assembly for a motor vehicle, comprising a crankshaft, a housing configured to house at least partially the crankshaft and comprising at least one receiving bearing for a crankshaft journal, the housing comprising a groove formed in a lateral face of a wall of the housing participating in delimiting the receiving bearing, the engine assembly further comprising at least one axial stop device configured to be housed within the groove between said lateral face and the crankshaft, characterized in that the axial stop device comprises a first portion and a second distinct portion, both configured to be housed within the groove, each portion comprising a positioning lug configured to cooperate by complementary shape with a notch formed at one end of the groove.

[0008] Thanks to the two-part axial thrust bearing, any confusion is avoided regarding the type of axial thrust bearing to be installed during engine assembly. It can be decided that the two-part axial thrust bearings are intended for one type of engine assembly, while other single-part axial thrust bearings are intended for a second type of engine assembly. This eliminates the risk of installing the wrong axial thrust bearing and ensures proper crankshaft operation.

[0009] The housing is specially adapted to receive the crankshaft, for example by being molded to conform to the contours of the crankshaft journals and form receiving bearings defining the crankshaft's axis of rotation, while allowing crankshaft journals, offset from the journals and engaged with engine pistons, to be set in motion. The housing is in two parts arranged on either side of the crankshaft, each part comprising walls having a semi-circular shape that allows the crankshaft shaft to form receiving bearings when the two parts are assembled. The groove is located on a lateral face of one of these walls, this lateral face being intended to be aligned with a lateral bearing surface of the crankshaft that axially defines the journal.

[0010] The axial stop device is therefore arranged within this groove and conforms to the shape of a portion of the crankshaft journal around the axis of rotation of the latter. Once in place, the axial stop device is therefore within the groove of the housing, axially interposed, considering the axis of rotation of the crankshaft, between the lateral face of a wall of the housing and a lateral bearing surface of the crankshaft and thus prevents any axial movement of the latter, that is to say any movement parallel to an axis of rotation of the crankshaft.

[0011] The groove extends over the entire dimension of the semicircle, and it has Notches are located at each end of the groove, forming a wider receiving area compared to the rest of the groove. Portions of the thrust bearing are slid into the groove with the crankshaft already in place and can be inserted through these notches. A positioning lug for a portion of the thrust bearing is located at the end of that portion and consists of a larger area, for example, taller or thicker, than the corresponding dimension of the rest of the portion. The positioning lug provides a final stop for the thrust bearing portion to be inserted into the groove. The shape of the positioning lug is complementary to the notch in the groove into which it is to be inserted, thus ensuring easy assembly of the thrust bearing onto the housing. This also allows for verification that the thrust bearing is correctly positioned.

[0012] According to one feature of the invention, each portion is in the shape of a circular arc. And according to another feature of the invention, the two portions have a dimension defining the extent of the circular arc that is identical from one portion to the other. The groove extends in a semicircle within the wall that forms a receiving bearing for a crankshaft journal. In order for the two portions to be inserted into the same groove, and insofar as they have angular dimensions defining the extent of the circular arc that are similar from one portion to the other, they have at most a quarter-circle shape.

[0013] According to one feature of the invention, each portion comprises a rounded end opposite the positioning heel, the rounded ends of the two portions forming the axial stop device being opposite each other within the groove. The rounded ends help to limit potential mechanical stresses due, for example, to micro-design defects.

[0014] According to one feature of the invention, each portion comprises an inner face oriented towards the housing and an outer face opposite the inner face and oriented towards the crankshaft, the outer face of each portion comprising a lubrication cavity. When the portions forming the axial thrust bearing device are arranged in the groove, the inner face is pressed against the bottom of the housing groove, while the outer face is in contact with the crankshaft bearing once the engine assembly is fully assembled.

[0015] The lubrication cavity forms a space between each of the portions and the crankshaft journal so that lubricating fluid can circulate in this area defining the axis of rotation of the crankshaft within the housing, thus reducing crankshaft friction.

[0016] According to one feature of the invention, the first portion and the second portion comprise respectively a first positioning lug and a second lug The positioning tabs, the first and second, are of different shapes and / or sizes. These tabs allow the two portions of the axial stop device to be positioned correctly. They also act as a guide, as each tab only aligns with one of the notches in the groove due to its complementary shape.

[0017] The keying function ensures that the external face, and therefore the lubrication cavity, is aligned with the crankshaft journal so that the latter is properly lubricated by the lubricating fluid.

[0018] According to one feature of the invention, the first positioning lug and the second positioning lug each have a connecting face linking the inner face to the outer face, the first portion and the second portion being configured to be arranged in the groove so that the connecting face of each positioning lug is in the same plane with respect to each other.

[0019] More particularly, these connecting faces are flush with a joining surface of the part of the housing in which the groove is made, so that these connecting faces extend as far as possible into the groove without interfering with the assembly of the two parts of the housing to enclose the crankshaft.

[0020] According to one feature of the invention, the axial stop device is made of metal. By way of example, the axial stop device may comprise a steel base and also contain an aluminum-tin alloy.

[0021] According to one feature of the invention, the engine assembly may include two axial thrust bearing devices configured to be positioned on either side of the crankshaft journal. In other words, the crankshaft journal is held by two axial thrust bearing devices, for a total of four portions joined in pairs. Such a configuration ensures better support of the crankshaft in both directions relative to the axial direction.

[0022] The invention also covers a method for assembling an engine assembly as described above, comprising: - a step to determine the diameter of the crankshaft, - a step of arranging the axial stop device in two portions when The crankshaft diameter is compatible. - a step of arranging an axial thrust device of a different type than the two-part axial thrust device type when the crankshaft diameter is not compatible with the axial thrust device.

[0023] As previously mentioned, the two-part thrust bearing device is specific to a type of engine assembly. This can be identified by the diameter of the crankshaft journals, which may be a different dimension from one type to the other motor assembly. Once the dimensions are determined, the two portions of the axial thrust bearing can be installed if it is indeed the motor assembly with which this type of axial thrust bearing interacts in two separate portions. If not, then another thrust bearing must be installed, for example, a thrust bearing consisting of a single portion.

[0024] According to one feature of the method, the first portion of the axial stop device is inserted through one end of the groove and the second portion of the axial stop device through the other end of the groove. The two portions can be inserted one after the other or simultaneously. The complementary shape between the positioning lug of each portion and the notch at each end of the groove allows for optimal insertion of the axial stop device.

[0025] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given by reference to the accompanying schematic drawings on the other hand, in which:

[0026] [Fig-1] represents an exploded view of an engine assembly according to the invention,

[0027] [Fig.2] is a front view of an axial stop device arranged within the engine assembly.

[0028] Figure 1 is a partial representation of an engine assembly 1 according to the invention, seen in exploded view. The engine assembly 1 includes in particular a crankshaft 2 and a housing 3 configured to accommodate at least partially the crankshaft 2.

[0029] The crankshaft 2 comprises a shaft formed by a plurality of journals 4, spaced apart and intended to be received respectively in a receiving bearing formed in the housing 3, and it comprises crankpins 6 interposed between the journals 4. The shaft and the journals 4 define an axis of rotation 5 of the crankshaft, and the crankpins 6 are offset with respect to this axis of rotation. As mentioned, the journals 4 cooperate with bearings of the housing 3 to allow the rotation of the crankshaft, and the crankpins 6 cooperate with pistons housed in cylinders formed in the housing 3 to transform the translational motion of the pistons into a rotational motion of the crankshaft.

[0030] The crankshaft 2 is connected to additional drive means outside the housing of the engine assembly, for example drive shafts of a gearbox not shown here.

[0031] The housing 3 defines a recess 7 allowing at least partial reception of the crankshaft 2. In [Fig. 1], a portion of the housing 3, intended to partially receive the crankshaft 2, is illustrated, it being understood that a second portion of the housing is fixed to the first portion of the housing to form a closed assembly within which the crankshaft, in particular, is housed. The recess 7 includes, in particular, spaces 8 arranged in the axial extension of cylinders in which the pistons of the engine assembly slide (not visible here), these spaces 8 allow freedom of movement of the crankpins 6 of the crankshaft 2, as well as walls 9 forming a semi-circular arch to form half-bearings for receiving a journal 4 of the crankshaft 2. It is understood that the second part of the housing 3, not visible here, has walls forming complementary arches to form additional half-bearings, the joining of these two parts of the housing at the level of opposing junction surfaces allowing the journal receiving bearing to be closed.

[0032] Maintaining the theoretical axial position of the crankshaft 2 is essential for the proper functioning of the engine assembly 1, ensuring that the crankpins 6 are correctly positioned relative to the translational movement of the gears within the cylinders formed in the housing 3. Therefore, once the crankshaft 2 is installed in the housing 3, any movement, particularly axial movement of the crankshaft 2—that is, along a direction parallel to the axis of rotation 5 of the shaft 4—must be strictly avoided. However, as previously mentioned, the crankshaft is connected outside the engine assembly to the drive elements of a gearbox, and the crankshaft can experience micro-shocks along its axial direction with each gear change.

[0033] To axially lock the crankshaft in the housing 3, the housing 3 includes at least one groove 10 and the engine assembly 1 includes at least one axial stop device 11 suitable for being inserted in the groove 10 to be axially interposed between a wall of the housing 3 and the crankshaft 2 in order to prevent any play of the latter in the axial direction, i.e. the direction parallel to the axis of rotation 5.

[0034] More specifically, the groove 10 is formed in a lateral face of the wall 9 that forms the receiving bearing for the housing 3. The crankshaft is configured such that two lateral bearing surfaces 5 axially frame the journal 4 intended to be received in this receiving bearing. These lateral bearing surfaces 5 are positioned on either side of the housing wall 9 and have a larger diameter than the journal 4 so as to be aligned with a lateral face of this wall 9. The groove 10 is machined into the material of this lateral face of the wall 9 along the axial direction. In this way, the axial distance between the housing wall 9 and the lateral bearing surface 5 of the crankshaft is locally increased. This clearance area is filled by the axial stop device, which has anti-friction properties and is dimensioned to ensure axial contact with both the housing wall and the lateral bearing surface of the crankshaft.

[0035] The groove 10 is made over the entire angular dimension of the receiving bearing formed by the wall 9, around the axis of rotation 5. In other words, here, the groove has a semi-circular shape and the axial stop device 11 has a corresponding shape which will be described below.

[0036] The axial stop device 11 can be metallic, for example made of steel with an aluminum and tin alloy.

[0037] The axial thrust bearing device 11 is installed during the assembly process of the engine assembly 1. This installation is performed manually within an assembly line for the engine assembly 1, or even for the entire internal combustion engine. However, several types of engine assemblies are sometimes assembled within these assembly lines, which can lead to confusion regarding the appropriate axial thrust bearing device for each type of engine assembly. If the axial thrust bearing device is inserted into an incompatible engine assembly, the axial thrust bearing device may move freely within the groove or, conversely, protrude from it. This can lead to several negative effects, such as assembly difficulties or a lack of stability in the axial direction.

[0038] The motor assembly 1 according to the invention avoids any confusion regarding the axial stop device 11 to be installed, as the latter comprises two distinct parts, namely a first portion 12 and a second portion 13, both intended to be inserted into the same groove 10. This axial stop device 11 in two portions 12, 13 is thus distinguished from other types of axial stop devices in a single portion. It is therefore understood that the axial stop device 11 in two portions 12, 13 is specific to the motor assembly 1 illustrated in [Fig. 1], which avoids any confusion for the operators responsible for assembling the motor assembly 1. There is thus no risk of installing the wrong axial stop device 11, as the type of axial stop device to be installed in a given motor assembly is determined beforehand.

[0039] Generally speaking, it is the diameter of the shaft, and more specifically of the crankshaft journals 4, that varies from one type of engine assembly to another. A first step in an assembly process is therefore to check the diameter of a journal 4, either by measurement or by verifying a marking previously made by the crankshaft manufacturer. When the diameter of the journal requires it, that is to say when the engine assembly is of a first type, and once the crankshaft is in position against the housing, with the journals against the walls of the housing forming receiving bearings for these journals, the axial thrust device 11 in two portions 12, 13 is arranged in the groove 10. Otherwise, when the verified diameter of the journal is specific to an engine assembly of a different type than the first type mentioned, it is a third thrust device, for example a thrust device in a single portion, which must be put in place.

[0040] The portions of the axial stop device are housed in the groove 10 while the crankshaft journal 4 is against the housing wall 9, with the lateral bearing surfaces 5 delimiting the journal 4 which are opposite the lateral faces of this wall 9 of the The housing. Portions 12, 13 of the axial thrust bearing device 11 are thus inserted through one end of the groove 10, their angular position within the groove 10 being defined by the interaction described below between a positioning lug for a portion and a notch in the groove. It should be noted that in [Fig. 1] only one groove 10 is shown, on a lateral face of a wall 9 of the housing, but the housing 3 may include several grooves 10 configured to each receive an axial thrust bearing device 11 in two portions 12, 13. In particular, a groove 10 may be formed on each of the lateral faces of the same wall 9 of the housing intended to form a receiving bearing for a journal 4, so that an axial thrust bearing device 11 is positioned on either side of at least one of the journals 4 of the crankshaft 2.

[0041] Fig. 2 is a cross-sectional view, in a plane at the junction of a journal and the lateral bearing of the crankshaft, showing the axial stop device 11 in two portions 12, 13 inserted in the groove 10 formed in the wall 9. Fig. 2 also shows a second part of the housing, which completes the arch shape of the wall 9 to close the receiving bearing of the crankshaft journal 4.

[0042] The two portions 12, 13 are here each in the shape of a quarter circle, the axial stop device 11 being in the shape of a semicircle capable of fully filling the corresponding angular dimension of the groove around the axis of rotation 5.

[0043] More generally, the shape of the two portions 12, 13 is in the form of an arc of a circle which allows them to at least partially follow the shape of the journal 4 of the crankshaft.

[0044] The first portion 12 and the second portion 13 respectively comprise a first positioning lug 14 and a second positioning lug 15 configured to cooperate by complementary shape with a notch 16. The groove thus comprises two notches 16 at each end, each of the notches 16 being intended to receive the positioning lug 14, 15 of one of the portions 12, 13.

[0045] Starting from the positioning lug 14, 15, each portion 12, 13 extends in the shape of a circular arc to a rounded end 17. When the portions 12, 13 are housed in the groove 10, these rounded ends 17 are intended to be facing, or even in contact with, each other. The rounded shape helps to limit mechanical stresses that may, for example, be due to manufacturing tolerances of the portions 12, 13.

[0046] As previously mentioned, portions 12, 13 of the axial stop device 11 are inserted through one end of the groove 10, i.e., through one of the notches. In other words, the assembly can be implemented so that the first portion 12 of the axial stop device 11 enters the groove through one end of this groove 10 and the second portion 13 of the axial stop device 11 enters the groove through a second end of the groove 10. the said ends corresponding to notches 16.

[0047] More specifically, simultaneously or successively, each portion is inserted into the groove by first passing its rounded end through its designated notch, and then sliding the portion into the groove until the positioning lug engages with the complementaryly shaped notch and prevents the portion from being inserted. When the positioning lug of a portion of the axial stop device is in contact with the edges defining the notch, the portion is in the desired angular position within the groove 10.

[0048] Furthermore, each portion 12, 13 comprises an inner face and an outer face 19, only the outer face 19 being visible in [Fig. 2]. When the axial stop device 11 is arranged within the groove 10, the inner face is oriented towards the wall 9 forming the receiving bearing for the trunnion 4, so as to face the inside of the groove 10, while the outer face 19 is opposite the inner face and is configured to be oriented towards the lateral bearing surface 5, not visible in [Fig. 2] due to the cross-sectional view, axially delimiting the trunnion 4. The outer face 19 of each of the portions 12, 13 is distinguished from the inner face in that it comprises a lubrication cavity 20 within which a lubricating fluid can circulate.

[0049] The first positioning lug 14 and the second positioning lug 15 have different dimensions relative to each other. More specifically, the positioning lugs 14 and 15 differ from each other in length L14, L15 and height H14, H15. Alternatively, the positioning lugs 14 and 15 may differ in their shape.

[0050] Each notch 16 of the groove 10 is dimensioned to specifically receive either the first positioning lug 14 or the second positioning lug 15. In other words, one notch has a first dimension, for example a height, which is equal to the height H14 of the first positioning lug, while the other notch has a second dimension, for example a height, which is equal to the height H14 of the second positioning lug. In this way, the operator can easily verify that the positioning lug of the portion he has just inserted is in the correct notch. Such a configuration ensures that each portion 12, 13 is positioned correctly, so that the outer face 19 of each portion 12, 13 faces the lateral bearing surface of the crankshaft and not the housing wall.The dimensions of the positioning lugs 14, 15 therefore serve as a guide to ensure that the lubrication cavity 20 of each portion is correctly aligned with the crankshaft so that the latter is properly lubricated.

[0051] Each portion 12, 13, more particularly each positioning heel 14, 15, It includes a connecting face 21 linking the inner face to the outer face 19 and forming the thickness of each portion 12, 13. Once the portions 12, 13 are positioned in the groove 10, the connecting faces 21, which are diametrically opposed with respect to the journal, must be arranged in the same plane P, which forms a junction plane with a complementary part of the housing to form the journal receiving bearing. Thus, the axial stop device 11 is only located on one side of plane P, thereby facilitating the assembly of the motor assembly. In the context of what has been described above, if the connecting faces 21 are not flush with plane P once the portions are inserted into the groove, the operator can assume that the portions have not been inserted on the correct side of the groove and can repeat the operation.

[0052] Of course, the invention is not limited to the examples just described and many modifications can be made to these examples without departing from the scope of the invention.

[0053] The invention, as described above, achieves its intended purpose and provides a motor assembly comprising an axial stop device in two parts, allowing for identification of how to be specifically assembled within said motor assembly. Variants not described here could be implemented without departing from the scope of the invention, provided that, in accordance with the invention, they comprise a motor assembly conforming to the invention.

Claims

Claims

1. Engine assembly (1) for a motor vehicle, comprising a crankshaft (2), a housing (3) configured to at least partially house the crankshaft (2) and comprising at least one bearing for receiving a journal (4) of the crankshaft (2), the housing (3) comprising a groove (10) formed in a lateral face of a wall (9) of the housing participating in delimiting the receiving housing, the engine assembly further comprising at least one axial stop device (11) configured to be housed within the groove (10) between said lateral face and the crankshaft (2), characterized in that the axial stop device (11) comprises a first portion (12) and a second portion (13) distinct, both configured to be housed within the groove (10), each portion (12, 13) comprising a positioning heel (14, 15) configured to cooperate by complementarity of shape with a notch (16) formed at one end of the groove (10).

2. An engine assembly (1) according to claim 1, wherein each portion (12, 13) is in the shape of an arc of a circle.

3. Engine assembly (1) according to any one of the preceding claims, in which each portion (12, 13) comprises a rounded end (17) opposite the positioning heel (14, 15), the rounded ends (17) of the two portions (12, 13) forming the axial stop device (11) being opposite each other within the groove (10).

4. Engine assembly (1) according to any one of the preceding claims, in which each portion (12, 13) comprises an internal face oriented towards the housing (3) and an external face (19) opposite the internal face and oriented towards the crankshaft (2), the external face (19) of each portion (12, 13) comprising a lubrication cavity (20).

5. An engine assembly (1) according to any preceding claim, wherein the first portion (12) and the second portion (13) respectively comprise a first positioning heel (14) and a second positioning heel (15), the first positioning heel (14) and the second positioning heel (15) being of different shape and / or size relative to each other.

6. Engine assembly (1) according to the preceding claim, combined with claim 4, in which the first positioning heel (14) and the second positioning heel (15) each have a connecting face (21) connecting the inner face to the outer face (19), the first portion (12) and the second portion (13) being configured to be arranged in the groove (10) so that the connecting face (21) of each positioning heel (14, 15) is in the same plane (P) relative to each other.

7. Engine assembly (1) according to any one of the preceding claims, wherein the axial stop device (11) is made of metal.

8. Engine assembly (1) according to any one of the preceding claims, comprising two axial stop devices (11) configured to be arranged each on either side of the journal (4) of the crankshaft (2).

9. Method for assembling several types of engine assemblies within an assembly line, including a first type of engine assembly (1) according to any one of the preceding claims and another type of engine assembly, comprising: - a step of determining a diameter of the crankshaft (2), - a step of arranging the axial stop device (11) in two portions when the diameter of the crankshaft (2) is compatible, the first type of engine assembly (1) interacting with said axial stop device (11), - a step of arranging a third axial stop device, of a type different from the type of axial stop device in two portions, when the diameter of the crankshaft (2) is not compatible with the axial stop device (11) and is specific to an engine assembly of a type other than the first type of engine assembly (1).

10. Assembly method according to the preceding claim, during which the first portion (12) of the axial stop device (11) is inserted via a first end of the groove (10) and the second portion (13) of the axial stop device (11) via a second end of the groove (10).

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