EP1070834A1 - Combustion engine with a spacer on the oil pan - Google Patents

Abstract

The automobile power unit comprises a thermal engine (12) and a transmission (14). A rear face (16) of the longitudinal engine block (18) is rigidly connected to a front face (20) of a transmission bell housing (22) for the flywheel. At right angles to the fixing plane of an oil sump (28) under the engine block are two horizontal corner irons (26) each comprising a longitudinal front first branch rigidly fixed to the engine block and a second transverse rear branch rigidly fixed to the bell housing. The first front branches of the two corner irons are rigidly fixed to a brace (42) interposed vertically between the engine block and the oil sump.

Description

The invention relates to a powertrain for motor vehicle.

The invention relates more particularly to a group powerplant for a motor vehicle comprising longitudinally, from front to back, a heat engine and a transmission, of the type in which a rear face of a block longitudinal of the heat engine is rigidly linked to one side front of a transmission bell, including a bell for a flywheel, of the type which comprises, in line with a plane fixing an oil pan under the engine block, two horizontal brackets, transversely opposite, comprising each a first fixed longitudinal front branch rigidly to the engine block, and a second rear branch transverse rigidly attached to the bell to stiffen the assembly of the engine and the transmission.

We know many examples of groups powertrains of the type described above.

Most of them are powertrains, the heat engine is of large displacement and whose shaft outlet, integral with the crankshaft, is likely to cause the transmission with significant torque.

During operation, due to the vibrations to which is subject the engine and, more generally, the group powertrain as a whole, the attachment points of the engine block on the transmission case are subject to longitudinal bending stresses.

Furthermore, it was also found that, due to the friction that exists between the different bearings of the crankshaft and the output shaft, part of the engine torque is likely to be partially transmitted, especially during engine recoveries, to the engine block in the form of a couple around the direction of the output shaft of the motor, which has the effect of shearing stress on the fixing points of the engine block on the crankcase transmission, and to twist the casing of the transmission.

The engine block fixing points on the crankcase transmission are conventionally made in the form screw and nut assemblies.

Under the effect of bending stresses and stresses due to the engine torque partially transmitted to the block, these screws and nuts can be deformed, this which can cause difficulties when, for example, you want to remove the engine from the vehicle by separating it from the transmission.

In addition, the bending and torsional stresses to which the engine block and the housing of the transmission can cause deformation of the bearings which guide the rotating elements of the engine and the transmission, in particular engine crankshaft bearings, an engine output bearing, and an input shaft bearings of the transmission.

The deformation of these bearings can cause wear accelerated rotating elements they carry as well as lubricant leaks.

To remedy this drawback, it has been proposed to fix between the engine block and a bell of the transmission housing brackets of the type described above.

This design makes it possible to stiffen so satisfactory the connection between the engine block and the crankcase transmission, but it has many drawbacks.

To achieve a satisfactory fixing, the brackets must have many anchor points, making makes them awkward to assemble and disassemble, both from the point of view of the time spent on this operation, position of anchor points before mounting.

In addition, the multiplicity of anchor points further increases the number of machining operations to be carried out on the engine block and on the transmission housing bell, this which increases the cost of manufacturing such an engine block and the transmission housing.

Finally, to present satisfactory resistance, these brackets must be made of a material such as cast iron, which weighs down the powertrain.

To remedy these drawbacks, the invention proposes brackets integrated into an additional element of the block engine.

To this end, the invention proposes a powertrain of the type described above, characterized in that it has a spacer which is vertically interposed between the engine block and the oil pan, and on which are fixed rigidly the first branches before the two brackets.

This spacer advantageously allows to benefit an increase in the lubricating oil capacity of the motor and, depending on the shape of the spacer, to mount different types of oil pan on the same engine block.

• l'entretoise du carter d'huile présente sensiblement la forme d'un parallélépipède dont une face supérieure est complémentaire de la forme du contour de la face inférieure du bloc moteur, et dont la face inférieure est complémentaire de la forme du contour de la face supérieure du carter d'huile, pour permettre l'adaptation d'un carter d'huile associé au bloc moteur,
• chaque équerre présente la forme d'un tétraèdre dont la base forme la deuxième branche arrière de l'équerre, et dont le corps forme la première branche de l'équerre,
• chaque équerre tétraédrique comporte, aux sommets de sa base les plus éloignés de l'axe médian du moteur, deux perçages longitudinaux pour la fixation par vissage de l'équerre sur une surface percée complémentaire de la cloche de transmission,
• le corps de chaque équerre comporte un évidement qui débouche dans sa base pour alléger et rigidifier l'équerre,
• les équerres sont réalisées venues de matière avec l'entretoise,
• l'entretoise est obtenue par moulage, notamment d'un alliage d'aluminium,
• l'entretoise parallélépipédique comporte des ouvertures qui débouchent entre ses faces supérieure et inférieure pour permettre le passage d'éléments d'un équipage mobile du moteur.

According to other characteristics of the invention:

• the oil pan spacer has substantially the shape of a parallelepiped, an upper face of which is complementary to the shape of the outline of the underside of the engine block, and the underside of which is complementary to the shape of the outline of the face upper part of the oil pan, to allow the adaptation of an oil pan associated with the engine block,
• each square has the shape of a tetrahedron whose base forms the second rear branch of the square, and whose body forms the first branch of the square,
• each tetrahedral bracket has, at the vertices of its base furthest from the median axis of the engine, two longitudinal holes for fixing by screwing the bracket on a complementary pierced surface of the transmission bell,
• the body of each bracket has a recess which opens into its base to lighten and stiffen the bracket,
• the brackets are made integrally with the spacer,
• the spacer is obtained by molding, in particular of an aluminum alloy,
• the parallelepipedic spacer has openings which open between its upper and lower faces to allow the passage of elements of a mobile engine assembly.

• la figure 1 est une vue partielle en perspective d'un groupe motopropulseur selon l'art antérieur comportant des équerres de liaison indépendantes ;
• la figure 2 est une vue partielle en perspective d'un groupe motopropulseur selon l'art antérieur comportant une entretoise selon l'invention ; et
• la figure 3 est une vue en perspective d'une entretoise selon l'invention.

Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

• Figure 1 is a partial perspective view of a powertrain according to the prior art comprising independent connecting brackets;
• Figure 2 is a partial perspective view of a powertrain according to the prior art comprising a spacer according to the invention; and
• Figure 3 is a perspective view of a spacer according to the invention.

In the description which follows, figures of identical reference denote identical elements or having similar functions.

We will use without limitation, and with reference to figures, the terms horizontal, vertical, longitudinal, transverse, front and rear.

We have shown in Figure 1 the whole group powertrain 10 for motor vehicle produced according to a state of the art.

In known manner, the powertrain 10 longitudinally, from front to back, a motor thermal 12 which is coupled to a transmission 14. One side rear transverse 16 of an engine block 18 is rigidly linked to a front face 20 of a bell 22 of a casing (not shown) of the transmission 14. The bell 22 is in particular made integrally with the casing (not shown) of the transmission 14 and it is intended to house a flywheel and / or a clutch (not shown) of the powertrain 10.

In known manner, the motor 12 comprises a crankshaft (not shown) which is coupled to a shaft A-axis output for driving the transmission 14 of the vehicle.

When the vehicle engine is running, the engine block 18 is subjected to vibrations and is therefore liable to transmit longitudinal bending stresses to the connection between the engine block 18 and the bell 22.

In addition, when, for example during a strong recovery of the engine 12 of the vehicle, the crankshaft is subjected to a torque important, it transmits part of this torque to the engine block 18 of motor 12 by means of the bearings which carry it so that the block 18 is partially rotated around axis A of the crankshaft and the output shaft of the engine 12. The connection of the engine block 18 to the bell 22 is is then strongly stressed in torsion, which is detrimental to the resistance of the power train 10.

Thus, according to the known conception of the state of technical, 26 brackets are provided which allow stiffen the assembly of the engine block 18 to the bell 22.

The engine block 18 being assembled to the bell 22 by through anchor points such as screws and nuts (not shown) arranged regularly on the face rear of block 18 of engine 12, the means for fixing the block motor 18 on bell 22 do not extend below a plan P for fixing a group 28 oil pan powertrain 10 under the engine 12.

The brackets 26 are arranged substantially in line with the fixing plane P, that is to say as low as possible relative to to axis A of the crankshaft of engine 12 so as to ensure resumption of the bending and torsional forces which are transmitted in from block 18 of engine 12. The powertrain 10 has two opposite brackets 26 which are arranged in the plane P, on either side of the axis A of the crankshaft.

As illustrated in FIG. 1, the brackets 26 are horizontal orientation and each have a first longitudinal front leg 30 which is fixed on a part in opposite the corresponding side face 34 of block 18 of the motor 12, and a second transverse rear branch 32 which is fixed on a part opposite the front face 20 of the bell 22 of the transmission 14.

The first longitudinal front branch 30 has substantially the shape of a plate which is bolted to the screw means 36 on the corresponding side face 34 of the block engine 18. The side face 34 of the engine block 18 is machined to this effect so as to have a flat support surface for the first front branch 30 of the square 26.

Similarly, the second rear branch 32 is bolted by means of screws 40 on the front face 20 of the transmission bell 22, which is also machined so appropriate.

Finally, a reinforcing rib 41 connects the first front leg 30 and second rear leg 32.

According to the invention, and as illustrated in the figure 2, a spacer 42, which includes brackets 26, is interposed between the block 18 of the engine 12 and the oil sump 28 motor 12.

In the preferred embodiment of the invention, the brackets 26 are integrated into the spacer 42, and they are made from material with it.

This provision is not limitative of the invention, and the brackets 26 may, as variants not shown, be independent brackets which are fixed in a way similar to that described with reference to FIG. 1, on the lateral faces 44 of the spacer 42. This arrangement allows in particular, during the assembly of the powertrain 10, to be able to assemble the engine block 18 and its equipment on the one hand, and the spacer 42 and the brackets 26 on the other hand, which saves time when the final assembly of the engine 12. During the final assembly of the powertrain 12, all that remains is to fix the second transverse rear branch 32 of the brackets 26 on the front face 20 of the bell 22 of the transmission 14.

However, the maximum rigidity of the final assembly powertrain 10 and minimal assembly time are obtained by making the spacer 42 and the brackets 26 one and the same room.

In accordance with the invention, the spacer 42 has substantially the shape of a parallelepiped, one face of which upper 46 is complementary to the shape of the contour of a lower face 48 of the engine block 18, and one lower face of which 50 is complementary to the shape of the contour of a face upper 52 of the oil pan 28.

In this way, the spacer 42 advantageously allows the adaptation of different types of housing from 28 to the same block motor 18, provided that for each case, a spacer 42 of suitable shape. This provision allows to significantly reduce the production costs of a chain engine manufacturing 12 to the extent that it is not necessary to provide engine block 18 corresponding to each type of oil pan 28, and as long as only one 18 "standard" engine block can be adapted to different housings oil 28.

Conversely, we can associate an oil pan 28 of adequate shape and capacity for each engine 12 in according to its power and its lubrication needs.

Figure 3 illustrates in more detail the shapes of the spacer 42.

In particular, the upper face 46, of contour C ₄₆ complementary to the contour of the corresponding part of the lower face 48 of the engine block 18 previously described, and the lower face 50, of contour C ₅₀ complementary of the contour of the corresponding part of the upper face 52 of the casing of 28.

The upper 46 and lower 50 faces have holes 53 for fixing the spacer 42 on the block engine 18 and on the oil pan 28.

The spacer 42 is produced in the form of a parallelepiped molded from an aluminum alloy which has openings 54 which open between its upper faces 46 and lower 50 to allow the passage of elements (not shown) of a mobile assembly of the engine 12, in particular balancing weights of a crankshaft of engine 12 and an engine timing pulley 12.

In accordance with the invention, the brackets 26 are made integrally with the spacer 42.

In the preferred embodiment of the invention, each square 26 has the shape of a tetrahedron whose base 56 forms the second rear branch 32 of the bracket 26, and whose body 72 forms the first front branch 30 of square 26.

The base 56 of each bracket 26 comprises, at its vertices 58 and 60 furthest from a median plane P ', which is vertical and contains the axis A of the crankshaft previously described, longitudinal holes 62 and 64 for fixing by screwing, using corresponding screws 66 and 68, the bracket 26 on a drilled and tapped surface (not shown) of the front face 20 of the bell 22. For this purpose, the base 56 of each angle is machined to allow a flat adjustment of these two surfaces.

Finally, the body 72 of each bracket 26 has a recess 70 from the molding of the spacer 42, which allows on the one hand to lighten the spacer 42, and on the other hand to increase the resistance of the bracket 26, a hollow volume being, for a same bending or twisting stress, more resistant than full volume which could crack.

Thus, advantageously, the spacer 42 makes it possible to stiffen the assembly of the engine 12 to the transmission 14, simplify the mounting of the brackets 26 by reducing the number of anchor points involved, and it increases the engine oil capacity 12 by adding an oil pan 28 of appropriate volume, which allows in particular, for a passenger vehicle in common use, to extend the interval of time between two successive oil changes.

Claims (8)

Powertrain (10) for a motor vehicle comprising longitudinally, from front to rear, a heat engine (12) and a transmission (14), of the type in which a rear face (16) of a longitudinal block (18) of the engine (12) thermal is rigidly linked to a front face (20) of a bell (22) of the transmission (14), in particular a bell (22) for a flywheel, of the type which comprises, in line with a plane (P) for fixing an oil pan (28) under the block (18) of the engine (12), two horizontal brackets (26), opposite transversely, each comprising a first longitudinal front leg (30) rigidly fixed to the engine block (18), and a second transverse rear branch (32) rigidly fixed to the bell (22) to stiffen the assembly of the engine (12) and the transmission (14),
characterized in that it comprises a spacer (42) which is vertically interposed between the engine block (18) and the oil sump (28), and on which the first front legs (30) of the two brackets are rigidly fixed ( 26). Powertrain (10) according to any one of the preceding claims, characterized in that the spacer (42) of the oil pan (28) has substantially the shape of a parallelepiped, an upper face (46) of which is complementary to the shape of the contour of the underside (48) of the engine block (18), and the lower face (50) of which is complementary to the shape of the contour of the upper face (52) of the oil pan (42), to allow the adaptation of a oil pan (28) associated with the engine block (18). Powertrain (10) according to claim previous, characterized in that each bracket (26) has the shape of a tetrahedron whose base (56) forms the second rear branch (32) of the bracket (26), and the body (72) forms the first branch (30) of the bracket (26). Powertrain (10) according to claim previous, characterized in that each bracket (26) tetrahedral has, at the vertices (58, 60) of its base (56) furthest from a median plane (P ') of the motor (12), two longitudinal holes (62, 64) for fixing by screwing the square (26) on a pierced surface complementary to the transmission bell (22). Powertrain (10) according to one of Claims 3 or 4, characterized in that the body (72) of each bracket has a recess (70) which opens into its base (56) to lighten and stiffen the bracket (26). Powertrain (10) according to any one claims 1 to 5, characterized in that the brackets (26) are made integrally with the spacer (42). Powertrain according to any one of Claims 1 to 6, characterized in that the spacer (42) is obtained by molding, in particular of an aluminum alloy. Powertrain (10) according to any one of claims 2 to 7, characterized in that the spacer (46) parallelepiped has openings (54) which open out between its upper (46) and lower (50) faces to allow the passage of elements of a mobile equipment of the motor (12).

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