FR2811269A1 - Automobile power unit set comprises engine shaft, differential with crown wheel controlling driving wheels and gearbox with output shaft which carries pinion meshing with crown wheel - Google Patents

Abstract

The power unit set comprises an engine shaft (1), a differential (3) with a driving crown wheel (31) which controls the vehicle driving wheels. A gearbox (4) comprises an output shaft (2), which is rotated with a variable reduction ratio by the engine shaft, and carries a pinion (201) meshing with the crown wheel. The engine shaft, the output shaft and the rotating differential casing (30) are each rotationally guided by an upstream bearing (14,20,35) mounted on the clutch housing (10).

Description

The present invention relates to a powertrain for a vehicle

  automobile, such as a thermally propelled vehicle or a vehicle

hybrid drive.

  The term “hybrid propulsion” is understood here to mean propulsion which is produced from a heat engine and / or an electric motor, the vehicle

  being equipped with these two types of engine.

  The powertrain which is the subject of the invention comprises, in a conventional manner, a main drive shaft driven in rotation by a heat engine by means of a clutch, a gearbox and a

  differential which controls the drive wheels of the vehicle.

  EP 0 545 102 already discloses such a powertrain. In the single figure of this document, it can be seen that a differential comprises a rotary unit whose axis of rotation corresponds to the axis common to the two half-shafts of the wheels of the vehicle to be driven. Inside the housing are guided in rotation two bevel gears, called satellite gears, carried by shaft sections and two other bevel gears, called planetary gears, carried at the respective ends of the two half-shafts of the drive wheels. The rotary case is integral with a differential drive ring. In addition, this housing is guided in rotation by two bearings of

  bearing, hereinafter called "upstream" bearing and "downstream" bearing respectively.

  In the following description and in the claims, it is

  will designate by "upstream" rolling bearing of any rotary element, the bearing located on the heat engine side and by "downstream" rolling bearing, the bearing

  located on the opposite side, towards or inside the gearbox.

  In the figure of document EP 0 545 102, it can also be seen that the gearbox comprises a main drive shaft rotated by a heat engine (not shown) and a gearbox output shaft or output shaft, parallel to this motor shaft and driven in rotation by it

  according to a variable gear ratio.

  The motor shaft is driven by the heat engine via a clutch (not shown in the figure), housed in a clutch housing. In addition, the output shaft carries a relatively small pinion, called the main pinion, of which it is integral both in rotation and in translation. This

  main gear meshes with the crown of the differential.

  As can be seen in the figure of document EP 0 545 102, such an assembly of the various elements of the powertrain has the disadvantage that the "upstream" rolling bearing of the rotary differential case is located just under the clutch housing. , which prevents possibly increasing the radial dimension of the latter, except having to also move

  the differential down (in the direction of the figure).

  The objective of the invention is to provide a powertrain of the type indicated above, which makes it possible to increase the radial size of the clutch housing, without increasing the overall dimension of the powertrain in

the radial direction.

  More specifically, the object of the invention is a powertrain for a motor vehicle comprising: - at least one so-called main motor shaft, driven in rotation by a heat engine via a clutch, - a differential which is provided with a drive crown and which controls the driving wheels of the vehicle, and - a gearbox comprising an output shaft, driven in rotation according to a variable reduction ratio by said main drive shaft, and which carries a pinion in taken with the differential drive ring gear, the drive shaft, the output shaft and the rotary differential case each being guided in rotation at least by a mounted "upstream" rolling bearing

on the clutch housing.

  This powertrain is remarkable in that the "upstream" rolling bearing of the differential housing and the "upstream" rolling bearing of the gearbox output shaft are substantially in the same vertical plane, perpendicular to the axis of said output shaft, the axial dimensions of the "upstream" rolling bearing of the differential housing overlapping at least in part

  the axial size of the "upstream" rolling bearing of the output shaft.

  Thanks to these characteristics of the invention, the "upstream" rolling bearing of the differential housing is no longer under the bottom wall of the clutch housing, which allows, if necessary, to increase the radial dimension of the clutch housing or more precisely to move this lower wall in the direction of the differential. Thus, in the case of a hybrid propulsion vehicle, it becomes possible to place inside the clutch housing an electric motor of the "pancake" type, more powerful than a conventional electric motor, but also of a larger diameter. In this case, the powertrain comprises a second, said auxiliary, tubular motor shaft, driven by the electric motor and surrounding

the main drive shaft.

  It is also possible to introduce inside the clutch housing any element having a large size, since this clutch housing can be enlarged without increasing the

  overall dimension of the powertrain in the radial direction.

  The invention thus meets the desired compactness requirements

for a powertrain.

  In addition, the relative position of these two rolling bearings

  "Upstream" improves the mechanical strength of the clutch housing.

  Furthermore, according to a certain number of additional, non-limiting characteristics of the invention: - the "upstream" rolling bearing of the differential housing and the "upstream" rolling bearing of the output shaft of the gearbox are in the same vertical plane, perpendicular to the axis of said output shaft, the axial dimensions of the "upstream" rolling bearing of the differential housing completely overlapping the axial dimensions of the "upstream" rolling bearings of the exit; - the "upstream" rolling bearing of the motor shaft and the "upstream" rolling bearing of the output shaft are substantially in the same vertical plane, perpendicular to the axis of said output shaft, the axial size of the "upstream" rolling bearing of the drive shaft at least partially overlapping the axial size of the "upstream" rolling bearing of the output shaft; - the "upstream" rolling bearing of the motor shaft and the "upstream" rolling bearing of the output shaft are in the same vertical plane, perpendicular to the axis of said output shaft, the axial size of the bearing upstream bearing of the motor shaft completely overlapping the space requirement

  axial of the "upstream" rolling bearing of the output shaft.

  Other characteristics and advantages of the invention will appear more

  clearly on reading the following description of an embodiment of

  the invention, given by way of illustrative and nonlimiting example, this description being

  made with reference to the attached drawing.

  In this drawing, FIG. 1 (single figure) is a sectional view,

  partial and schematic, of the powertrain according to the invention.

  There are designated respectively by the references X-X ', Y-Y' and Z-Z ', the axis of the main drive shaft 1, the axis of the output shaft 2 of the gearbox

  and the axis of rotation of the differential 3.

These three axes are parallel.

  More specifically, the main drive shaft I is rotated by a heat engine, not shown, located on the right of the figure. It is by

  example of a four-stroke petrol or diesel engine.

  This shaft is rotated by the heat engine, via a known type of clutch, not shown in the figure, and housed

in a clutch housing 10.

  This clutch housing 10 has a bottom wall or wall 1l 1 and a lower peripheral wall 12. The wall 1l 1 is pierced with a circular opening 1 3. This allows the passage of the motor shaft I in the direction of the gearbox and is provided with an "upstream" rolling bearing 14 ensuring rotation guidance

said motor shaft.

  The motor shaft 1 has a series of pinions of which only one,

  referenced 100, is shown in Figure 1.

  The gearbox, referenced 4, is shown partially and very schematically. It is housed in a gearbox casing 40. It comprises at least one rotary shaft, in particular the receiving shaft or output shaft 2 of the gearbox. This output shaft 2 is guided in rotation by two rolling bearings, positioned respectively at its two opposite ends and called "upstream" bearing and "downstream" bearing. Only the "upstream" bearing 20 located on the side

  of the heat engine (right side in Figure 1) is shown.

  The output shaft 2 carries a series of pinions 200 of which only two are shown in FIG. 1 and which are each engaged with one of the pinions

  main drive shaft.

  In known manner, this allows the output shaft 2 to be driven in rotation by the main drive shaft 1, according to different gear ratios. The output shaft 2 further carries a pinion 201, relatively small,

  said main pinion, of which it is integral in rotation and in translation.

  This main gear 201 is used to drive the differential in rotation.

  In a manner also known, the differential 3 comprises a rotary housing 30 whose axis of rotation Z-Z 'corresponds to the axis common to the two half-shafts of the wheels to be driven. This housing 30 is integral with a drive ring 31 thanks to fixing means such as screws 310. The pinion

  main 201 meshes with this drive ring 31.

  Inside the housing 30 are guided in rotation, on the one hand two bevel gears, called planet gears 32, 32 ', carried by shaft sections 33, respectively 33', and on the other hand, two other gears bevel gears, called planetary gears 34, 34 ', carried at the respective ends of the two half-shafts of the driving wheels. Each of the two planet gears 32, 32 'meshes with the two planetary gears 34, 34', their conicity being adapted in

result.

  The rotary housing 30 is guided in rotation by two rolling bearings, referenced respectively 35 for the "upstream" bearing and 35 'for the "downstream" bearing. The rolling bearings 14 and 20, used respectively for shafts 1 and 2, are cylindrical roller bearing bearings, while the rolling bearings 35, 35 'used for the differential are conventionally

tapered roller bearings.

  The bearings 35, 35 'are provided on the outer wall of the housing 30 and for this purpose, the latter has cylindrical portions, respectively 350 and 350',

  allowing such rotation guidance.

  The outer ring 351 of the "upstream" bearing 35 of the differential housing is mounted on the one hand on the clutch housing 10, more precisely at the base of the wall 11 and on the other hand, on the housing 5 protecting the half-shafts from drive wheels.

  In the present description and in the claims, the term “

  "axial size" EA of a rolling bearing the distance between the two opposite outermost lateral faces of the inner and outer rings of said

  bearing, that is to say its "overall" thickness.

  In accordance with the invention, and as illustrated in FIG. 1, the axial size EA35 of the bearing of the "upstream" bearing 35 of the housing 30 of the reference frame overlaps at least in part (in the axial direction of the figure),

  the axial size EA20 of the bearing of the "upstream" bearing 20 of the output shaft 2.

  In other words, the "upstream" rolling bearings 35 and 20 are substantially

  in the same vertical plane, perpendicular to the axis Y-Y 'of the output shaft 2.

  This overlap, which is partial in the illustrated embodiment, is shown in the figure by a shaded area, referenced C. Advantageously, the axial dimensions EA3s and EA20 are

totally overlap.

  In addition, the axial size EA20 of the bearing of the "upstream" bearing of the output shaft 2 overlaps at least in part, or totally (as illustrated in FIG. 1), the axial size EA14 of the "upstream" rolling bearing 14

motor shaft 1.

  Thus, the three rolling bearings 14, 20 and 35 are

  substantially in the same plane, parallel to the web 11 of the clutch housing.

  This gives better mechanical strength of this clutch housing and the wall 12 of the clutch housing can be lowered in the direction of the differential 3, to allow for example, to place an electric motor of the "wafer" type for example - including the outline, referenced 6, is shown in the figure - inside the clutch housing 10, when dealing with a system of

hybrid drive.

  In this case, according to a known arrangement, the primary shaft is double.

  It consists of two coaxial shafts, namely a central shaft driven by the heat engine and an outer tubular shaft driven by the

electric motor.

Claims (4)

CLAIMS.   1. Powertrain for a motor vehicle, comprising: - at least one motor shaft (1), said to be main, driven in rotation by a heat engine via a clutch, - a differential (3) which is provided with a drive ring (31) which controls the drive wheels of the vehicle, and - a gearbox (4) comprising an output shaft (2), driven in rotation according to a variable reduction ratio by said main drive shaft ( 1), and which carries a pinion (201) in engagement with the differential drive crown, the drive shaft (1), the output shaft (2) and the rotary housing (30) of the differential being each guided in rotation at least by an "upstream" rolling bearing (14, 20, 35) mounted on the clutch housing (10), characterized in that the "upstream" rolling bearing (35) of the housing (30) of the differential and the "upstream" rolling bearing (20) of the gearbox output shaft are substantially in a n same vertical plane, perpendicular to the axis YY 'of said output shaft 2, the axial space requirement (EA35) of the "upstream" rolling bearing (35) of the differential housing at least partly overlapping the axial space requirement (EA20 ) of the "upstream" rolling bearing (20) of said output shaft. 2. Powertrain according to claim 1, characterized in that the "upstream" rolling bearing (35) of the housing (30) of the differential and the "upstream" rolling bearing (20) of the output shaft (2) of the gearbox are in the same vertical plane, perpendicular to the axis YY 'of said output shaft, the axial dimensions (EA35) of the "upstream" rolling bearing (35) of the differential housing completely overlapping the dimensions axial (EA20) of the bearing   "upstream" bearing (20) of the output shaft.   3. Powertrain according to claim 1 or 2, characterized in that the "upstream" rolling bearing (14) of the motor shaft (1) and the "upstream" rolling bearing (20) of the output shaft (2) are substantially in the same vertical plane, perpendicular to the axis YY 'of said output shaft, the axial size (EAI4) of the "upstream" rolling bearing (14) of the motor shaft overlapping at least in part the axial size (EA20) of the "upstream" rolling bearing (20) of the output shaft.   4. Powertrain according to claim I or 2, characterized in that the "upstream" rolling bearing (14) of the motor shaft (1) and the "upstream" rolling bearing (20) of the output shaft (2) are in the same vertical plane, perpendicular to the axis YY 'of said output shaft, the axial dimensions (EA14) of the "upstream" rolling bearing (14) of the drive shaft completely overlapping the axial dimensions (EA20) of the "upstream" rolling bearing (20) of the outlet (2).