EP1070834B1 - 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 power train for motor vehicle.

The invention relates more particularly to a group powertrain 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 axis of the engine is rigidly connected to one side front of a transmission bell, including a bell for a flywheel, of the type that includes, in the right of a plan fixing an oil pan under the engine block, two horizontal squares, transversely opposed, comprising each a first fixed longitudinal front branch rigidly to the engine block, and a second rear branch cross rigidly attached to the bell to stiffen engine and transmission assembly.

Many examples of groups are known powertrains of the type described above.

Most of them are powertrains the engine is of high displacement and the engine shaft exit, secured to the crankshaft, is likely to lead to transmission with a large torque.

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

In addition, it has also been found that friction that exists between the different bearings of the crankshaft and the output shaft, a part of the engine torque is likely to be partially transmitted, in particular during engine recoveries, to the engine block in the form of a couple around the direction of the exit tree of the motor, which has the effect of shearing the fixing points of the engine block on the housing of the transmission, and torsionally urging the casing of the transmission.

The attachment points of the engine block on the housing of the transmission are conventionally made in the form screw and nut assemblies.

Under the effect of bending stresses and motor torque partially transmitted to the motor block, these screws and nuts may be caused to deform, this which can result in difficulties when, for example, we want to drop the engine of the vehicle by disconnecting it from the transmission.

Moreover, the bending and torsion stresses to which the engine block and the crankcase of the transmission can cause deformation of the bearings which guide the rotating elements of the engine and the transmission, including engine crankshaft bearings, an engine output bearing, and bearings of an input shaft of the transmission.

Deformation of these bearings can cause wear accelerated rotating elements they wear 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 case brackets of the type described above.

This design makes it possible to stiffen satisfactory connection between the engine block and the housing of the transmission, but it has many disadvantages.

To achieve a satisfactory fixation, the squares must have many anchor points, which makes makes them difficult to assemble and disassemble, both from view of the time devoted to this operation, that of the position of anchor points before mounting.

Moreover, the multiplicity of anchor points increases all the number of machining to be performed on the engine block and the bell of the transmission casing, which increases the cost of manufacturing such a block engine and transmission case.

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

To overcome these drawbacks, document EP-0 368 478 proposes brackets integrated into an additional element of the engine block. However, brackets is not adapted to hold the bell in position optimally and in particular to absorb torsional stresses to which it is subject.

For this purpose, the invention proposes a powertrain of the type previously described, comprising a spacer which is interposed vertically between the engine block and the sump, and on which are rigidly fixed the first front branches of the two brackets.

This spacer advantageously allows to benefit from a increase the engine's lubricating oil capacity and, depending of the form of the spacer, to mount different types of sump on a same engine block.

According to the invention, the powertrain is characterized in that each square has the shape of a tetrahedron whose base forms the second branch back of the square, and whose body forms the first branch of the square.

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 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 features of the invention:

the oil pan spacer has substantially the shape of a parallelepiped whose upper face is complementary to the shape of the contour of the lower face of the engine block, and whose lower face is complementary to the shape of the contour of the face top of the oil sump, to allow the adaptation of an oil sump associated with the engine block;

each tetrahedral square comprises, at the vertices of its base farthest from the median axis of the motor, two longitudinal bores for fixing by screwing the bracket to a pierced surface complementary to the transmission bell,

• the body of each square has a recess which opens into its base to lighten and stiffen the square,
• the brackets are made integrally with the spacer,
• the spacer is obtained by molding, in particular an aluminum alloy,
• the parallelepiped spacer has openings which open between its upper and lower faces to allow the passage of elements of a movable engine.

• 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 features 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 having independent connecting brackets;
• Figure 2 is a partial perspective view of a power unit 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 that follows, figures of identical reference designates identical elements or having similar functions.

We will use without limitation, and with reference to figures, horizontal, vertical, longitudinal, transversal, front and back.

FIG. 1 shows the whole of a group power train 10 for a motor vehicle realized according to a state of the art.

In known manner, the powertrain 10 comprises longitudinally, from front to back, an engine 12 which is coupled to a transmission 14. A face rear transverse 16 of a motor unit 18 is rigidly connected to a front face 20 of a bell 22 of a housing (no represented) of the transmission 14. The bell 22 is particularly material made with the housing (not shown) of the transmission 14 and is intended to house a flywheel and / or a clutch (not shown) of the power train 10.

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

When the vehicle engine is running, the engine block 18 is subject to vibration and is therefore likely to transmit longitudinal bending stresses to the connection between the engine block 18 and the bell 22.

Moreover, when, for example during a strong recovery of the engine 12 of the vehicle, the crankshaft is subjected to a couple important, it transmits some of this torque to the engine block 18 of the engine 12 through the bearings that wear it from so that the block 18 is partially rotated around the axis A of the crankshaft and the output shaft of the 12. The connection of the engine block 18 to the bell 22 is is then strongly stressed in torsion, which is detrimental to the strength of the power train 10.

So, according to the known conception of the state of the technical, there are provided brackets 26 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 block 18 of the engine 12, the block fixing means motor 18 on bell 22 do not extend below a plane P for fixing a group oil pan 28 power train 10 under the engine 12.

The brackets 26 are arranged substantially in line with the P plane of fixation, that is to say the lowest possible relative to the axis A of the crankshaft of the engine 12 so as to ensure a recovery of bending and twisting forces that are transmitted in from block 18 of the engine 12. The power train 10 has two opposite squares 26 that 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 horizontally oriented and each include a first longitudinal front branch which is fixed on a part in vis-à-vis the corresponding side face 34 of the block 18 of 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 branch before longitudinal 30 presents substantially the shape of a plate that is bolted to means of screw 36 on the corresponding lateral face 34 of the block 18. The side face 34 of the engine block 18 is machined to this effect so as to have a flat bearing surface for the first branch before 30 of the square 26.

In a similar way, 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 appropriate.

Finally, a reinforcing rib 41 interconnects the first branch before 30 and second rear branch 32.

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

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

This provision is not limiting of the invention, and the brackets 26 may, as unrepresented variants, be independent brackets that are attached, in a way analogous to that described with reference to FIG. lateral faces 44 of the spacer 42. This arrangement allows in particular, during the assembly of the power train 10, to be able to separately 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 represents a saving of time at the time of the final assembly of the engine 12. In the final assembly of the power plant 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 minimum assembly time are obtained by producing the spacer 42 and the brackets 26 in one and the same room.

According to the invention, the spacer 42 presents substantially the shape of a parallelepiped of which one face upper 46 is complementary to the shape of the outline of a lower face 48 of the engine block 18, and a lower face of which 50 is complementary to the shape of the outline of a face upper 52 of the oil sump 28.

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

Conversely, one can associate an oil pan 28 of adequate shape and capacity to each engine 12 in depending on its power and lubrication needs.

Figure 3 illustrates in more detail the forms 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 motor unit 18 previously described, and the lower face 50 of contour C _{50 which is} complementary in contour to the corresponding portion of FIG. the upper face 52 of the housing 28.

The upper faces 46 and lower 50 comprise holes 53 for fixing the spacer 42 on the block motor 18 and on the sump 28.

The spacer 42 is made in the form of a parallelepiped molded of an aluminum alloy which comprises openings 54 which open between its upper faces 46 and lower 50 to allow the passage of elements (no represented) of a mobile engine 12, in particular balancing weights of a crankshaft of the engine 12 and a motor timing pulley 12.

According to the invention, the brackets 26 are made integrally with the spacer 42.

In the preferred embodiment of the invention, each bracket 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 branch before 30 of the square 26.

The base 56 of each square 26 comprises, at its vertices 58 and 60 farthest 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 the corresponding screws 66 and 68, the square 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 square is machined to allow a plane fit optimal 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 strength of the square 26, a hollow volume being, for a same bending or torsion stress, more resistant than full volume that could crack.

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

Claims (7)

1. Motor vehicle power train (10) comprising longitudinally, from front to rear, an internal combustion engine (12) and a transmission (14), of the type in which a rear side (16) of a longitudinal block (18) of the internal combustion engine (12) is rigidly connected to a front side (20) of a bell housing (22) of the transmission (14), in particular a bell housing (22) for a flywheel, of the type which comprises, perpendicular to a plane (P) in which a sump (28) is mounted under the block (18) of the engine (12), two transversely opposed, horizontal brackets (26) each comprising a longitudinal front first branch (30) fastened rigidly to the engine block (18), and a transverse rear second branch (32) fastened rigidly to the bell housing (22) to strengthen the assembly of the engine (12) and the transmission (14), the said power train (10) comprising a spacer (42) which is interposed vertically between the engine block (18) and the sump (28) and on which are rigidly fastened the front first branches (30) of the two brackets (26), characterized in that each bracket (26) has the shape of a tetrahedron whose base (56) forms the rear second branch (32) of the bracket (26) and whose body (72) forms the first branch (30) of the bracket (26).
2. Power train (10) according to Claim 1, characterized in that the spacer (42) of the sump (28) has approximately the shape of a parallelepiped whose upper side (46) is complementary in shape to the contour of the lower side (48) of the engine block (18) and whose lower side (50) is complementary in shape to the contour of the upper side (52) of the sump (28), so as to make it possible to fit a sump (28) associated with the engine block (18).
3. Power train (10) according to Claim 1, characterized in that each tetrahedral bracket (26) comprises, at the vertices (58, 60) of its base (56) which are furthest away from a mid-plane (P') of the engine (12), two longitudinal drilled holes (62, 64) for screw-fastening the bracket (26) to a complementary drilled surface of the transmission bell housing (22).
4. Power train (10) according to either of Claims 1 and 3, characterized in that the body (72) of each bracket comprises a cavity (70) which opens into its base (56) in order to lighten and strengthen the bracket (26).
5. Power train (10) according to any one of Claims 1 to 4, characterized in that the brackets (26) are produced as an integral unit with the spacer (42).
6. Power train according to any one of Claims 1 to 5, characterized in that the spacer (42) is obtained by moulding, in particular by moulding an aluminium alloy.
7. Power train (10) according to any one of Claims 1 to 6, characterized in that the parallelepipedal spacer (42) comprises openings (54) which open out between its upper (46) and lower (50) sides so as to allow the passage of elements of moving parts of the engine (12).

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