GB2173747A

GB2173747A - A four-wheel drive arrangement for a motor vehicle

Info

Publication number: GB2173747A
Application number: GB08604706A
Authority: GB
Inventors: Rolf V Sivers; Kim Havemann; Bernhard Ilsemann
Original assignee: Dr Ing HCF Porsche AG
Current assignee: Dr Ing HCF Porsche AG
Priority date: 1985-02-26
Filing date: 1986-02-26
Publication date: 1986-10-22
Also published as: FR2577858A1; DE3506727C1; GB8604706D0; JPS61200030A; FR2577858B1; GB2173747B; IT1188300B; IT8619155A0

Abstract

A transverse internal-combustion engine (2) drives front (9) and rear (10) wheels via a transmission (4,5), a differential gear (6) and an angular gear (8). To avoid excessive noise inside the vehicle, the angular gear (8), in addition to its fastening to the differential gear (6), is also fastened by support (14) to the internal-combustion engine (2), and the angular gear (8) is provided with a relatively short (dimension G) bearing neck (22) for the bearings (26,27) of its output shaft (23) which is connected to a propeller shaft arrangement (7). A connecting element (28) of the output shaft (23) projects only slightly (dimension H) beyond the free end of the bearing neck (22). in addition resilient resonance uncoupling devices (32) and (39) are provided between the output shaft (23) and the rear differential gear (41). <IMAGE>

Description

SPECIFICATION A four-wheel drive arrangement for motor vehicles This invention relates to a four-wheel drive for motor vehicles, particularly for passenger cars which have an in-line internal-combustion engine mounted at the front, preferably in front of the front axle transversely to the longitudinal direction of the vehicle, and in which the internal-combustion engine drives the front and rear wheels via a transmission, for example, a gear box comprising a clutch, a differential gear and an angular gear.

In a known vehicle with four-wheel drive (DE-OS 33 17 247), an angular gear has a relatively long bearing neck, extending in the longitudinal direction of the vehicle, for an output shaft which is connected to a two-part propellor shaft. The length of the output shaft is therefore also relatively long.

In addition, the angular gear extends a certain distance from the transversely located internal-combustion engine; i.e., it is fastened only at the differential gear. A disadvantage of this construction is that, due to the angular gear being connected at the output side and to the total length of the bearing neck and its oputput shaft, whip-like accelerations occur during the operation of the motor vehicle, causing excessive noise inside the vehicle. This noise is further affected by the bending vibrations of the two-part propeller shaft, which, via the angular gear, is incited by the second order of the speed of the four-cylinder internal-combustion engine.

It is the object of the present invention to take such measures at the angular gear, or at adjacent units, and at the propellor shaft of a vehicle having a four-wheel drive, such that the noise in the vehicle throughout the speed range of the internalcombustion engine does not exceed an acceptable level and driving is enhanced.

The present invention consists in a four-wheel drive arrangement for motor vehicles, particularly for a passenger car, comprising an in-line internalcombustion engine mounted at the front end, the engine driving the front and rear wheels of the vehicle via a transmission, for example, a gearbox, a clutch, a differential gear and an angular gear, wherein the angular gear, in addition to its fastening to the differential gear, is also supported at the internal-combustion engine and the angular gear, for the bearing of its output shaft which is connected to a propellor shaft arrangement, has a bearing neck which extends longitudinally of the vehicle, said bearing neck being relatively short but ensuring an adequate bearing base, the free end of said bearing neck being projected over only slightly by a connecting element of the output shaft, and a resonance uncoupling device is provided between the output shaft and the propellor shaft arrangement.

The main advantages achieved by the invention are that, by means of the connection of the angular gear to the internal-combustion engine, and the relatively short overall length of the bearing neck and of the output shaft, and the resonance uncoupling of the output shaft from the angular gear, noise levels inside the vehicle during operation are low. The console-type support is not only easy to manufacture, but can also be fastened without problems at the angular gear and at the internalcombustion engine, for example, by means of screws. When the effective base of the support extends over a significant part of the height of the internal-combustion engine housing, relative movements between the angular gear and the internal-combustion engine are largely avoided.The connection of the support at a partition of the internal-combustion engine ensures operationally effective power transmission.

The favourable vehicle behaviour with respect to inside noise is enhanced also by the fact that the clutch housing and the differential gear housing may be combined into one constructional unit, and that the bearing neck of the differential gear, with respect to its outside wall, is preferably supported by star-shaped ribs. Also contributing to this behaviour are the outside walls of the housing which may extend round the bearing neck without any significant contractions, as well as the supporting web which extends between the outside wall and the bearing neck of the differential gear housing.

Finally, the three part propeller shaft arrangement operates without resonance while in connection with an upright and transversely installed fourcylinder in-line internal-combustion engine running up to a speed of 7,000 revolutions per minute. In this regard, the constant velocity joints also ensure a uniform rotating motion of the centre shaft section when the shaft sections, for constructional reasons are not located in one plane.

In the accompanying drawings Figure 1 is a plan view of a drive unit of a motor vehicle having a four-wheel drive according to the present invention; Figure 2 is a cross-sectional and enlarged view of detail X of Figure 1; Figure 3 is an enlarged view taken in the direction of the arrow A of Figure 1, but rotated through 1 80 ; Figure 4 is an enlarged sectional view taken along the line IV-IV of Figure 3; Figure 5 is a view corresponding to Figure 4 of another embodiment; Figure 6 is an enlarged perspective view, taken approximately in the direction of the arrow B shown in Figure 1, of a constructional unit detached from an internal-combustion engine of the drive unit taken along the line Y-Y in Figure 1; and Figure 7 is a diagram useful for the purpose of demonstrating the results of the invention.

Referring now to Figure 1, the four-wheel drive unit 1 of a passenger car comprises an internalcombustion engine 2 extending transversely to the longitudinal direction C-C of the vehicle. The fourcylinder internal-combustion engine has vertically arranged cylinders, is positioned in front of a front axle indicated by the line 3, and is connected to a gearbox 5 containing a clutch 4. A differential gear 6 is connected to the output side of the bearbox 5 and to an angular gear 8 connected with a propel lor shaft arrangement 7. The front wheels 9 and the rear wheels 10 are driven via the differential gear 6 and the angular gear 8, with the front wheels 9 driven by the axle shafts 11, and the rear wheels 10 driven by the axle shafts 12.

At 13, the angular gear 8 is connected to the differential gear 6 and extends approximately parallel to and at a distance C from the internal-combustion engine 2, and is fastened to the engine. A console-type support 14 is used for this purpose and is arranged on the side of the angular gear 8 that faces away from the differential gear 6. The support 14, which is formed by a deep-drawing process, a casting process, or a similar process, is connected with the angular gear 8 and the internalcombustion engine 2 by means of screws 15 and 16 (Figure 3). In addition, the effective base D of the support 14 on the side of the internal-combustion engine extends across a substantial part of the height E of a housing 17, in this case the cylinder crankcase of the engine.

In order to avoid flexing movements of the wall of the housing 17, the vertically extending support 14 is connected to the internal-combustion engine 2 in the area of a partition which also forms a main bearing 19 for a crankshaft that is not shown (Figure 4).

In the embodiment shown in Figure 5, instead of the support 14, a housing 20 of the angular gear 8 has a supporting flange 21 screwed to housing 17.

The housing 20 of the angular gear 8 is provided with a bearing neck 22 for an output shaft 23 extending in the longitudinal direction C-C of the vehicle, the bevel gear 24 of the bearing neck meshing with a bevel gear 25 (Figure 1) powered by the differential gear 6. The bearing neck 22 is relatively short (distance G), but nevertheless has an adequate bearing base for two tapered roller bearings 26 and 27 which are arranged coaxially and at a short distance from one another and in which the output shaft 23 is disposed. The output shaft 23, at its free end, is provided with a connecting element 28 that is fastened on it and only slightly projects over the bearing neck 22 - distance H in Figure 2.The connecting element 28 of the output shaft 23 is connected to the propellor shaft arrangement 7, which has three interconnected shaft sections 29, 30 and 31 arranged sequentially via a resonance uncoupling device 32. The resonance uncoupling device 32 is, for example, formed by a resilient disc, such as a rubber disc into which fastening sleeves are vulcanized.

The centre shaft section 30 is connected with the shaft sections 29 and 31 by synchro-joints 33 and 34. In addition, it is disposed in ball bearings 35 and 36 which are fastened to the body, preferably the floor panel, of the motor vehicle by holders 37 and 38. Details of the body and the floor panel are not shown.

The rear shaft section 31 is connected with a rear axle differential gear 41, having a centre differential 40 by another resonance uncoupling device 39 of similar construction to the uncoupling device 32.

Between the rear axle differential gear 41 and the uncoupling device 39, a visco-coupling may also be provided.

In addition to the above-described features, the clutch housing 42 and differential gear housing 43 which are combined into one constructional unit may be reinforced as shown in Figure 6. Accordingly, a bearing neck 44 of the differential gear housing 43, with respect to an at least partially circularly extending outside wail 45, is supported by several ribs 46, 47, 48, 49, 50, 51 extending in a star-shaped manner. Some of these ribs terminate at lugs 52, 53, 54, 55 and 56 located beyond the outside wall. The lugs are used for fastening the differential gear housing 43 to the angular gear 8.

In addition, the outside walls 45 and 57 of the constructional unit, especially in the transition areas 58 and 59 between the two housings, are of a uniform height so as not to impair the stiffness of the constructional unit. Finally, a supporting web 60 is provided between the outside wall 45 of the differential gear 6 and the bearing neck 44.

In the diagram shown in Figure 7, the accelerating g is entered on the ordinate, and the engine speed in revolutions per minutes is entered on the abscissa. The solid line 61 shows a drive unit having a bearing neck of conventional length and an angular gear that has no support relative to the engine. This diagram shows that over a relatively large speed range, an unacceptable acceleration value occurs. This acceleration value can be considerably reduced for a structure which incorporates the features of the present invention, as demonstrated by the interrupted line 62.

Claims

1. Afour-wheel drive arrangement for motor vehicles, particularly for a passenger car, comprising an in-line internal combustion engine mounted at the front end, the engine driving the front and rear wheels of the vehicle via a transmission, for example, a gearbox, a clutch, a differential gear and an angular gear, wherein the angular gear, in addition to its fastening to the differential gear, is also supported at the internal-combustion engine and the angular gear, for the bearing of its output shaft which is connected to a propeller shaft arrangement, has a bearing neck which extends longitudinally of the vehicle, said bearing neck being relatively short but ensuring an adequate bearing base, the free end of said bearing neck being projected over only slightly by a connecting element of the output shaft, and a resonance uncoupling device is provided between the output shaft and the propellor shaft arrangement.

2. A four-wheel drive arrangement according to claim 1, wherein the angular gear is supported at the internal-combustion engine by a console-type support.

3. A four-wheel drive arrangement according to claim 2, wherein the support is mounted on the end of the angular drive that faces away from the differential gear.

4. A four-wheel drive arrangement according to claim 2 or 3, wherein the support is fastened to the angular gear and to the internal-combustion en gine threaded members.

5. A four-wheel drive arrangement according to any of claims 2 to 4, wherein the effective base of the support at the internal-combustion engine extends over a substantial part of the height of a housing of the internal-combustion engine.

6. A four-wheel drive arrangement according to any of claims 2 to 5, wherein the support is formed by a component made in a deep-drawing process, a casting process or similar process.

7. A four-wheel drive arrangement according to claim 5, wherein the substantially vertically extending support is connected in the area of a transverse wall of the housing of the internalcombustion engine.

8. A four-wheel drive arrangement according to any of claims 1 to 7, wherein a housing of the angular gear interacts, at least locally via support flanges, with the internal-combustion engine.

9. A four-wheel drive arrangement according to any of caims 1 to 8, wherein a clutch housing and a differential gear housing form a constructional unit having a bearing neck that is supported with respect to an outside wall, and wherein lugs are provided at said outside wall for the fastening of the differential gear to the angular gear, and wherein between the bearing neck and the outside wall of the differential gear housing, star-shaped ribs extend at least partially to the lugs.

10. A four-wheel drive arrangement according to claim 9, wherein the outside walls of the constructional unit, particularly in the transition area between the clutch housing and the differential gear, extend without significant contractions.

11. A four-wheel drive arrangement according to claims 9 or 10, wherein a supporting web extends between the bearing neck and the circular outside wall of the differential gear housing.

12. A four-wheel drive arrangement according to any of the preceding claims, wherein the propellor shaft arrangement comprises three interconnected shaft sections the centre shaft section being connected with the sections via synchronous joints, and wherein the end shaft sections interact, respectively, with the angular gear and a rear axle differential gear by means of resilient discs.

13. A four-wheel drive arrangement according to claim 12, wherein the centre shaft section is arranged in bearings which, by means of holders, are held at an adjacent wall of the vehicle body.

14. A four-wheel drive arrangement for motor vehicles substantially as described with reference to, and as illustrated in, the accompanying drawings.