Engine assembly for motor vehicles

Abstract

The present invention relates to an engine assembly (1) for a motor vehicle, comprising a crankshaft (2) and a housing (3) configured to at least partially house the crankshaft (2) and having at least one bearing for receiving the journal (4) of the crankshaft (2), wherein the housing (3) has grooves (10) formed in the side surface of the housing wall (9) which serve to define the receiving housing. The engine assembly further comprises at least one axial restraint device (11) configured to be housed in the groove (10). The axial restraint device (11) comprises a first part (12) and a second part (13), both configured to be housed in the groove (10), wherein each part (12, 13) has a positioning heel configured to cooperate complementarily with a notch formed at one end of the groove (10).

Description

Technical Field

[0001] The present invention relates to the field of heat engines for heat engine vehicles, and more specifically, to engine assemblies for such heat engines.

Background Art

[0002] The engine assembly includes a housing, in which a piston is configured to move within an engine cylinder under the effect of fuel combustion, and the housing accommodates a crankshaft that can convert the translational motion of the piston into the rotational motion of the crankshaft that is subsequently transmitted to the wheels.

[0003] In particular, the crankshaft comprises journals that define the rotational axis of the crankshaft and are supported by rotary bearings formed in the engine housing, and crank pins that are offset from the journals and connected to the pistons.

[0004] Then, the rotational motion of the crankshaft is transmitted to the wheels via the pinion and the layshaft of the gearbox. This configuration will cause a slight impact during gear shifting, which may generate a slight displacement of the crankshaft along its rotational axis. Accordingly, it is known to provide at least one axial stop to prevent axial movement of the journal of the crankshaft in the corresponding receiving bearing formed in the housing. The purpose is to ensure that the crank pin of the crankshaft is maintained in alignment with the translational axis of the engine piston.

[0005] The axial stop is located in the bearing region of the journal, between the lateral bearing surface of the crankshaft that axially defines the journal and the wall of the engine housing, in a groove formed in said wall for this purpose.

[0006] This type of axial restraint is manually installed on the heat engine assembly line. On the other hand, several heat engine models may be assembled on the same assembly line. These different heat engines may have different characteristics from one another, and in particular, they may have crankshaft dimensions such as journal diameters that can vary from engine to engine. Therefore, an axial restraint pre-designed for the crankshaft of one model of heat engine may be potentially incompatible with other heat engines, and incorrect axial restraint installation may occur. The axial restraint may be too small for the groove, resulting in the restraint not completely filling the groove, which may lead to a risk of axial instability of the crankshaft due to the journal not being locked in an axially uneven manner. Conversely, the axial restraint may be too large for the groove, causing it to protrude from the groove, which may lead to a risk of obstructing the assembly of engine housing components from both sides of the crankshaft. [Overview of the Initiative]

[0007] The present invention makes it possible to avoid the above-mentioned installation errors by proposing an engine assembly for a motor vehicle, the engine assembly comprising a crankshaft and a housing configured to at least partially accommodate the crankshaft and having at least one bearing for receiving the journal of the crankshaft, the housing having grooves formed on the side of the wall of the housing and involved in defining the receiving housing. The engine assembly further comprises at least one axial restraint device configured to be accommodated in the groove between the side and the crankshaft. The axial restraint device comprises a first part and a separate second part, both configured to be accommodated in the groove, each part having a positioning heel configured to cooperate complementarily with a notch formed at one end of the groove.

[0008] The two-part axial restraint device avoids any confusion regarding the type of axial restraint to be mated during engine assembly. It is possible to determine that the two-part axial restraint device is for a first type of engine assembly, and that the other single-part axial restraint is for a second type of engine assembly. This eliminates the risk of incorrect axial restraint placement and ensures that the crankshaft operates correctly.

[0009] The housing is specially adapted to receive the crankshaft, for example, by being shaped to form a receiving bearing that defines the axis of rotation of the crankshaft, while the crankpin of the crankshaft can be set to operate eccentrically with respect to the journal and in engagement with the piston of the engine. The housing consists of two parts positioned on either side of the crankshaft, each part having a semicircular wall portion into which the crankshaft can be received by forming a bearing when the two parts are assembled. A groove is located on one side of these wall portions, which faces the lateral bearing surface of the crankshaft that defines the journal in the axial direction.

[0010] Therefore, the axial restraint device is positioned within this groove and conforms to the shape of a portion of the crankshaft journal around the axis of rotation of the crankshaft journal. Thus, when in place, the axial restraint device is located within the groove of the housing and is axially sandwiched between the side of the housing wall and the lateral bearing surface of the crankshaft with respect to the axis of rotation of the crankshaft, thereby preventing axial movement of the crankshaft, i.e., any movement parallel to the axis of rotation of the crankshaft.

[0011] The groove extends along the entire length of the semicircle, with notches at each end of the groove, forming enlarged receiving areas compared to the rest of the groove. A portion of the axial restraint device can slide through the notches into the groove when the crankshaft is already in place. A positioning heel for a portion of the axial restraint device is positioned at the end of this portion and consists of an area that is larger in dimension than the corresponding dimension of the rest of the portion, for example, a taller or thicker dimension. The positioning heel provides an end restraint for inserting the axial restraint portion into the groove. The positioning heel is morphologically complementary to the notches in the groove with which it abuts, thereby ensuring easy assembly of the axial restraint device to the housing. This also allows for verification that the axial restraint device is correctly positioned.

[0012] According to one feature of the present invention, each part is arc-shaped. According to another feature of the present invention, the two parts have dimensions that define the same arc range between the parts. The groove extends in a semicircle within the wall portion that forms a bearing for receiving the journal of the crankshaft. In order to allow the two parts to be introduced into the same groove, and insofar as the two parts have angular dimensions that define the range of mutually similar arcs, the two parts are at most quarter-circular in shape.

[0013] A feature of the present invention is that each part has a rounded end on the opposite side of the positioning heel, and the rounded ends of the two parts forming the axial restraint device face each other in the groove. The rounded ends make it possible to limit potential mechanical stress, for example, caused by minute design defects.

[0014] According to the features of the present invention, each part comprises an inner surface oriented toward the housing and an outer surface opposite to the inner surface oriented toward the crankshaft, and the outer surface of each part comprises a lubrication cavity. When the part forming the axial restraint device is positioned in the groove, the inner surface is pressed against the bottom of the groove within the housing, but when the engine assembly is fully assembled, the outer surface contacts the crankshaft bearing.

[0015] The lubrication cavity forms a gap between each of the above-mentioned parts and the journal of the crankshaft, allowing the lubricating fluid to circulate within this region that defines the axis of rotation of the crankshaft within the housing, thereby reducing friction on the crankshaft.

[0016] According to the features of the present invention, the first and second parts each comprise a first positioning heel and a second positioning heel, the first and second positioning heels having different shapes and / or sizes from each other. The positioning heels enable the two parts of the axial restraint device to be positioned correctly. Thus, the positioning heels have a positioning function simply by each of them cooperating with one of the groove notches through their complementary shapes.

[0017] The coded function ensures that the outer surface and therefore the lubrication cavity faces the crankshaft journals, thereby ensuring that the crankshaft journals are properly lubricated by the lubricating fluid.

[0018] According to the features of the present invention, each of the first positioning heel and the second positioning heel has a connecting surface that connects its inner surface to its outer surface, and the first and second parts are configured to be positioned in a groove such that the connecting surfaces of each positioning heel are in the same plane relative to each other.

[0019] More specifically, these connecting surfaces are flush with the joint surfaces of the housing parts in which the grooves are formed, so that these connecting surfaces extend as far as possible within the grooves and surround the crankshaft without interfering with the assembly of the two housing parts.

[0020] According to the features of the present invention, the axial restraint device is made of metal. For example, the axial restraint device may be made of a steel base, and may also contain an alloy of aluminum and tin.

[0021] According to the features of the present invention, the engine assembly may include two axial restraint devices, each configured to be positioned on either side of the journal of the crankshaft. In other words, the journal of the crankshaft is gripped by the two axial restraint devices, i.e., a total of four parts joined together in pairs. This configuration provides better support to the crankshaft in both axial directions.

[0022] The present invention also includes the above-described method for assembling the engine assembly, Steps to determine the diameter of the crankshaft, If the crankshaft diameter is compatible, the steps include positioning axial restraint devices on two parts, If the diameter of the crankshaft does not fit the axial restraint device, the steps are to place an axial restraint device of a different type than the axial restraint device in two parts, It is equipped with.

[0023] As mentioned earlier, a two-piece restraint device is specific to one type of engine assembly. An engine assembly can be identified by the diameter of the crankshaft journal, which can have different dimensions for each type of engine assembly. Once the dimensions are determined, if it is indeed an engine assembly where that type of axial restraint device interacts in two separate parts, then the two parts of the axial restraint device are matable. Otherwise, another restraint device, such as a single-piece restraint device, should be mated.

[0024] In this method, a first portion of the axial restraint device is inserted into the first end of the groove, and a second portion of the axial restraint device is inserted into the second end of the groove. The two portions can be inserted sequentially or simultaneously. The complementary shapes between the positioning heels of each portion and the notches at each end of the groove ensure optimal insertion of the axial restraint device. [Brief explanation of the drawing]

[0025] [Figure 1] An exploded view of the engine assembly according to the present invention is shown. [Figure 2] It is a front view of an axial restraining device arranged inside the engine assembly. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] Other features and advantageous effects of the present invention will become apparent from the following description on the one hand, and from a number of embodiments given by way of illustration and without limitation with reference to the accompanying schematic drawings on the other hand.

[0027] Figure 1 is a partially exploded view of the engine assembly 1 according to the present invention. The engine assembly 1 particularly includes a crankshaft 2 and a housing 3 configured to accommodate at least a portion of the crankshaft 2.

[0028] The crankshaft 2 includes a shaft formed by a plurality of mutually spaced journals 4, each of which is adapted to be received in a respective receiving bearing formed in the housing 3, and includes crankpins 6 sandwiched between the journals 4. The shaft and the journals 4 define a rotation axis 5 of the crankshaft, and the crankpins 6 are offset from the center relative to this rotation axis. As described above, the function of the journals 4 cooperates with the bearings in the housing 3 to enable rotation of the crankshaft, and the crankpins 6 cooperate with pistons accommodated in cylinders formed in the housing 3 to convert the translational motion of the pistons into the rotational motion of the crankshaft.

[0029] The crankshaft 2 is connected to complementary drive means external to the engine assembly housing, for example, a gearbox drive shaft not shown here.

[0030] The housing 3 defines a recess 7 for at least partial reception of the crankshaft 2. Figure 1 shows a portion of the housing 3 for partial reception of the crankshaft 2, and it is understood that a second portion of the housing is fixed to a first portion of the housing to form a closed assembly in particular in which the crankshaft is housed. The housing 3 includes spaces 8 located in particular in the axial extension of the cylinder on which the piston of the engine assembly, which is not visible here, slides, and these spaces 8 allow free movement of the crankpin 6 of the crankshaft 2 and allow the formation of a half bearing for receiving the journal 4 of the crankshaft 2 by walls 9 that form a semicircular arc. The second portion of the housing 3, which is not visible here, includes walls that form a complementary arc that allows the formation of a complementary half bearing, and it is understood that the journal receiving bearing can be closed by the contact of these two portions of the housing at the height of the opposing mating surfaces.

[0031] Since the alignment of the crankshaft 2 with its theoretical axial position is essential for the correct operation of the engine assembly 1, the crankpin 6 is correctly positioned relative to the translational motion of the pinion in the cylinder formed within the housing 3. Therefore, once the crankshaft 2 is installed within the housing 3, any movement of the crankshaft 2, especially axial movement, i.e., movement parallel to the axis of rotation 5 of the shaft 4, must be avoided at all times. However, as previously mentioned, the crankshaft is connected to the drive elements of the gearbox outside the engine assembly, and the crankshaft is subjected to small axial shocks with each gear change.

[0032] To lock the crankshaft axially within the housing 3, the housing 3 is provided with at least one groove 10, and the engine assembly 1 is provided with at least one axial restraint device 11 that can be inserted into the groove 10 so as to be axially sandwiched between the wall of the housing 3 and the crankshaft 2, in order to prevent any axial play of the crankshaft 2, i.e., any play in any direction parallel to the rotation axis 5.

[0033] More specifically, the groove 10 is formed in the side surface of the wall 9 that forms the housing 3. The crankshaft is configured such that two lateral bearing surfaces 5 surround a journal 4 for receiving into this bearing, and these lateral bearing surfaces 5 have a larger diameter than the journal 4 so as to be positioned on both sides of the housing wall 9 and facing the side surface of this wall 9. The groove 10 is cut into the material of this side surface of the wall 9 along the axial direction. In this way, the axial distance between the housing wall 9 and the lateral bearing surfaces 5 of the crankshaft is locally increased, and this gap region is filled by an axial restraining device that has friction-preventing properties and is dimensioned to ensure axial contact with both the housing wall and the lateral bearing surfaces of the crankshaft.

[0034] The groove 10 is formed over the entire angular dimension of the receiving bearing formed by the wall portion 9 around the rotation axis 5. In other words, here the groove has a semicircular shape, and the axial restraint device 11 has the corresponding shape described below.

[0035] The axial restraint device 11 is made of metal, and may be made of steel, for example, an alloy of aluminum and tin.

[0036] The axial restraint device 11 is installed during the assembly process of the engine assembly 1. Such installation is performed manually within the assembly line for the engine assembly 1, or even for the heat engine as a whole. However, several types of engine assemblies may be assembled within these assembly lines, which can lead to confusion regarding which type of engine assembly the axial restraint device is suitable for. If the axial restraint device is inserted into an unsuitable engine assembly, it may float in or protrude from the groove. This can lead to numerous adverse effects, such as mounting difficulties or lack of axial stability.

[0037] The engine assembly 1 according to the present invention avoids any confusion regarding the axial restraint device 11 to be installed. This is because the axial restraint device 11 comprises two separate parts, namely a first part 12 and a second part 13, both of which are inserted into the same groove 10. Thus, the axial restraint device 11 in these two parts 12 and 13 is different from other types of axial restraint devices in a single part. This makes the axial restraint device 11 in the two parts 12 and 13 specific to the engine assembly 1 shown in Figure 1, thereby avoiding confusion for the worker responsible for assembling the engine assembly 1. This eliminates the risk of installing the wrong axial restraint device 11, as it is predetermined which type of axial restraint device must be placed in a given engine assembly.

[0038] Generally, what varies depending on the type of engine assembly is the diameter of the shaft, more specifically the journal 4 of the crankshaft 2. Therefore, the first step of the assembly process is to confirm the diameter of the journal 4 by measurement or by confirming markings previously made by the crankshaft manufacturer. If the journal diameter requires it, i.e., if the engine assembly is of the first type, the axial restraint device 11 in two parts 12, 13 is positioned in the groove 10, once the journals opposing the housing wall form bearings for receiving these journals and the crankshaft is in position relative to the housing. Alternatively, if the confirmed diameter of the journal is specific to an engine assembly of a type other than the first type, a third restraint device, such as a single-part restraint device, must be fitted.

[0039] The portion of the axial restraint device is housed in a groove 10 with the journal 4 of the crankshaft 2 facing the wall 9 of the housing, and the lateral bearing surface 5 defining the journal 4 faces the side of this wall 9 of the housing. This allows portions 12 and 13 of the axial restraint device 11 to be inserted into one end of the groove 10, and their angular positions within the groove 10 are defined by the cooperation of a heel and notch, described later, for positioning the portions within the groove. Although only one groove 10 is shown on the side of the wall 9 of the housing in Figure 1, it should be noted that the housing 3 may have several grooves 10, each configured to receive the axial restraint device 11 in two portions 12 and 13. In particular, grooves 10 may be formed on each of the same side surfaces of the wall 9 of the housing to form bearings for receiving the journal 4, thereby positioning the axial restraint device 11 on both sides of at least one of the journals 4 of the crankshaft 2.

[0040] Figure 2 is a plan view of the joint between the crankshaft journal and the lateral bearing surface, showing the axial restraint device 11 in two parts 12 and 13 inserted into grooves 10 formed in the wall 9. Figure 2 also shows a second part of the housing that completes the arc shape of the wall 9 and closes the bearing for the crankshaft journal 4.

[0041] Each of the two parts 12 and 13 is in the shape of a quadrant, and the axial restraint device 11 is in the shape of a semicircle that can completely fill the corresponding angular dimensions of the groove around the rotation axis 5.

[0042] More generally, the shapes of the two parts 12 and 13 are arc-shaped, and therefore at least partially match the shape of the crankshaft journal 4.

[0043] The first portion 12 and the second portion 13 each comprise a first positioning heel 14 and a second positioning heel 15, respectively, configured to cooperate with the notch 16 by complementarity of shape. The groove comprises two notches 16 at each end, each of which is designed to receive one of the positioning heels 14 and 15 of portions 12 and 13.

[0044] Each portion 12, 13 extends in an arc shape from the positioning heels 14, 15 to a rounded end 17. When portions 12, 13 are housed in the groove 10, these rounded ends 17 face each other or even come into contact. The rounded shape can limit mechanical stresses that may arise, for example, from manufacturing tolerances of portions 12, 13.

[0045] As previously mentioned, portions 12 and 13 of the axial restraint device 11 are introduced through one end of the groove 10, that is, through one of the notches. In other words, the assembly can be constructed such that the first portion 12 of the axial restraint device 11 enters the groove through the first end of the groove 10, and the second portion 13 of the axial restraint device 11 enters the groove through the second end of the groove 10, with both ends corresponding to the notches 16.

[0046] More specifically, each part is inserted into the groove either simultaneously or sequentially by first passing its rounded end through a notch specifically designed for it, and then sliding the part within the groove until the positioning heel cooperates with a complementaryly shaped notch to prevent further insertion of the part into the groove. When the positioning heel of a part of the axial restraint device contacts the edge defining the notch, the part is positioned at a desired angular position within the groove 10.

[0047] Furthermore, each section 12, 13 has an inner surface and an outer surface 19, although only the outer surface 19 is visible in Figure 2. When the axial restraint device 11 is positioned in the groove 10, the inner surface is oriented toward the wall 9 that forms a bearing for receiving the journal 4, facing inward into the groove 10. The outer surface 19, on the other hand, is opposite the inner surface and is configured to be oriented toward the lateral bearing surface 5, and is not visible in Figure 2 for the cross-sectional view that defines the journal 4 axially. Each outer surface 19 of sections 12, 13 differs from the inner surface in that it has a lubrication cavity 20 through which a lubricating fluid can flow.

[0048] The first positioning heel 14 and the second positioning heel 15 have different dimensions from each other. In particular, the positioning heels 14 and 15 differ from each other with respect to their lengths L14 and L15 and heights H14 and H15. Alternatively, the positioning heels 14 and 15 may differ in shape.

[0049] Each notch 16 of the groove 10 is specifically sized to receive either a first positioning heel 14 or a second positioning heel 15. In other words, one notch has a height equal to a first dimension, for example, the height H14 of the first positioning heel, and the other notch has a height equal to a second dimension, for example, the height H15 of the second positioning heel. In this way, the operator can easily verify that the positioning heel of the part they have just inserted is in the correct notch. This configuration ensures that each part 12, 13 is positioned in the correct location, thereby ensuring that the outer surfaces 19 of each part 12, 13 face the lateral bearing surface of the crankshaft and not the wall of the housing. Thus, the dimensions of the positioning heels 14, 15 act as locators, ensuring that the lubrication cavities 20 of each part face the crankshaft so that the crankshaft is properly lubricated.

[0050] Each portion 12, 13, and more specifically each positioning heel 14, 15, has a connecting surface 21 that connects its inner surface to the outer surface 19, forming the thickness of each portion 12, 13. When portions 12, 13 are positioned within the groove 10, the connecting surface 21 is diametrically opposite with respect to the journal and must be located within the same plane P, forming a joining plane with the complementary portion of the housing to form the journal receiving bearing. In this way, the axial restraint device 11 is located on only one side of plane P, thereby facilitating the assembly of the engine assembly. Against the backdrop of the above, if the connecting surface 21 is not flush with plane P, when the portion is inserted into the groove, the worker will assume that the portion was not inserted into the correct side of the groove and will resume work.

[0051] Naturally, the present invention is not limited to the examples described above, and numerous modifications can be made to these examples without departing from the scope of the invention.

[0052] The present invention, as described above, fully achieves its intended purpose and enables the provision of an engine assembly comprising axial restraint devices in two parts that can be identified as having to be specifically assembled within the engine assembly. Modifications not described herein can be implemented without leaving the context of the present invention, provided that they comprise the engine assembly according to the present invention.

Claims

1. An engine assembly (1) for a motor vehicle, comprising a crankshaft (2) and a housing (3) configured to at least partially house the crankshaft (2) and having at least one bearing for receiving the journal (4) of the crankshaft (2), wherein the housing (3) has grooves (10) formed in the side surface of the wall portion (9) of the housing which serve to define the receiving housing, and the engine assembly further comprises at least one axial restraint device (11) configured to be housed inside the groove (10) between the side surface and the crankshaft (2), The axial restraint device (11) comprises a first portion (12) and a separate second portion (13), both configured to be housed within the groove (10), and each portion (12, 13) includes a positioning heel (14, 15) configured to cooperate complementarily with a notch (16) formed at one end of the groove (10), in the engine assembly (1).

2. The engine assembly (1) according to claim 1, wherein each of the aforementioned parts (12, 13) has an arc shape.

3. The engine assembly (1) according to claim 1 or 2, wherein each of the portions (12, 13) has a rounded end (17) opposite to the positioning heels (14, 15), and the rounded ends (17) of the two portions (12, 13) forming the axial restraint device (11) face each other in the groove (10).

4. The engine assembly (1) according to any one of claims 1 to 3, wherein each of the portions (12, 13) comprises an inner surface oriented toward the housing (3) and an outer surface (19) opposite to the inner surface oriented toward the crankshaft (2), and the outer surface (19) of each of the portions (12, 13) comprises a lubrication cavity (20).

5. The engine assembly (1) according to any one of claims 1 to 4, wherein the first part (12) and the second part (13) each 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 shapes and / or sizes from each other.

6. The engine assembly (1) according to any one of claims 1 to 5, in combination with claim 4, wherein each of the first positioning heel (14) and the second positioning heel (15) has a connecting surface (21) that connects the inner surface to the outer surface (19), and the first portion (12) and the second portion (13) are arranged in the groove (10) such that the connecting surfaces (21) of each of the positioning heels (14, 15) are in the same plane (P) relative to each other.

7. The engine assembly (1) according to any one of claims 1 to 6, wherein the axial restraint device (11) is made of metal.

8. The engine assembly (1) according to any one of claims 1 to 7, comprising two axial restraint devices (11) each configured to be positioned on either side of the journal (4) of the crankshaft (2).

9. A method for assembling an engine assembly (1) according to any one of claims 1 to 8, The steps include determining the diameter of the crankshaft (2), If the diameter of the crankshaft (2) is suitable, the steps include arranging the axial restraint device (11) in two parts, If the diameter of the crankshaft (2) does not fit the axial restraint device (11), the steps are to place an axial restraint device of a different type from the axial restraint device in two parts, An assembly method that includes [a specific feature / feature].

10. The assembly method according to claim 9, wherein, during the assembly method, the first portion (12) of the axial restraint device (11) is inserted into the first end of the groove (10), and the second portion (13) of the axial restraint device (11) is inserted into the second end of the groove (10).

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