Mounting arrangement for final drive unit for automotive vehicles

Abstract: A differential case (16) of an automotive vehicle is arranged adjacent an internal combustion engine (10) and is connected to an oil pan (40) arranged beneath the engine. The enclosure is inclined at a predetermined angle in a direction in which the upper portion of the enclosure is inclined toward the engine. The enclosure has a pair of openings (30) in its side wall through which the axle shafts (36) pass. The axle shafts (36) are also inclined at the same angle as the enclosure. One of the axle shafts (36) passes through openings formed in the side walls of the oil pan so as to extend to the opposite side of the oil pan. The inclination of the enclosure and axle shafts allows the height of an engine hood and the width of the vehicular body to be decreased.

Description: BACKGROUND OF THE INVENTION Field of The Invention The present invention relates generally to a mounting arrangement for a final drive unit including a differential and a pair of axle shafts for automotive vehicles. More specifically, the invention relates to an improved mounting arrangement of a final drive unit for automotive vehicles in which an enclosure for receiving a differential case is arranged adjacent a longitudinally-mounted type engine. Description of The Background Art Conventionally, in the case of four-wheel drive vehicles on which an internal combustion engine is longitudinally mounted at the front of the vehicular body, a transmission is connected to the rear portion of the engine, and an enclosure for receiving a differential case is arranged beneath an oil pan of the engine. The transmission is connected to a final drive unit including the differential case and a pair of axle shafts via a propeller shaft and joints. The axle shafts extend horizontally to pass through openings formed in the side walls of the enclosure of the final drive unit to project therefrom. The ends of the projected portions of the axle shafts are connected to front-right and front-left wheels via joints, respectively. In such a mounting arrangement or structure, the total height of the engine becomes relatively high so that the position of an engine hood becomes relatively high since the final drive unit is arranged beneath the oil pan of the engine. Therefore, such a mounting arrangement can not be applied to a low profile automotive vehicle. A mounting arrangement for an automotive vehicle according to the preamble of claim 1 is known from EP-A-0 183 051. This document discloses an improved mounting arrangement in which an enclosure for receiving a differential case is arranged adjacent an engine. In this arrangement, the enclosure is connected to the side wall of an oil pan, and a pair of axle shafts extend horizontally to pass through openings formed in the side walls of the oil pan. However, there is a disadvantage in that such a mounting arrangement can not applied to automotive vehicles other than vehicles which are wide enough to mount a lower link of a suspension system at a location adjacent the enclosure of the final drive unit, since the enclosure of the final drive unit occupies a relatively large space at a location adjacent the engine. If such a mounting arrangement is applied to a vehicle having a narrow width, the length of the lower link must be shortened, which degrades driving stability. SUMMARY OF THE INVENTION It is therefore a principal object of the present invention to provide a mounting arrangement for a final drive unit which can be applied to an automotive vehicle, of which the heights of the engine and engine hood are relatively low, and which can allow a lower link of a suspension system to be mounted on a vehicular body without increasing the width thereof. This object is solved according to the invention by the subject matter of claim 1. Preferred embodiments of the invention are subject matter of the subclaims. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood more fully from the detailed description given herebelow and from the accompanying drawings of the preferred embodiment of the invention. However, the drawings are not intended to imply limitation of the invention but are for explanation and understanding only. In the drawings: Fig. 1 is a schematic side view showing a mounting arrangement for a final drive unit, according to the present invention; Fig. 2 is a top view of the mounting arrangement of Fig. 1; Fig. 3 is a sectional view of the mounting arrangement taken along the line III-III of Fig. 2. Fig. 4 is a sectional view of the mounting arrangement taken along the line IV-IV of Fig. 2. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, particularly to Fig. 1, there is shown a mounting arrangement for an engine 10, a transmission 12 and a final drive unit 14. The mounting arrangement of invention can be particularly applied to automotive vehicles, in which the engine is longitudinaly mounted at the front of the vehicle body, such as a four-wheel drive vehicle. As can be seen clearly from Fig. 2, the transmission 12 is arranged at a location behind the engine 10, and the final drive unit 14 is arranged adjacent the engine 10. Now referring to Fig. 3, the final drive unit 14 comprises an enclosure comprised of upper and lower halves 16a and 16b respectively, a differential case 20, a differential pinion gear 22, a differential side-gear 24, a ring-gear 26 and a final drive pinion 28, similarly to conventional arrangements. The upper enclosure 16a engages the lower enclosure 16b so as to define a space therein. The differential case 20 is housed within the space defined by the upper enclosure 16a and the lower enclosure 16b to be rotatably supported at the upper enclosure 16a via bearings 30a and 30b. As is well known, the differential pinion gear 22 and the differential side-gear 24 are housed within the differential case 20. The ring-gear 26 is fixed to the differential case 20 and engages the final drive pinion 28. The final drive pinion 28 is connected to the transmission 12 via a joint 32 and a propeller shaft 34. A pair of axle shafts 36a and 36b are supported on the differential case 20 via the differential pinion gear 22 and the differential side-gear 24, so that the rotation force of the propeller shaft 34 is transmitted to the axle shafts 36a and 36b via the differential case 20. The axle shafts 36a and 36b pass through openings formed in both side walls of the upper enclosure 16a to project therefrom, respectively. The end portions of the axle shafts 36a and 38b are connected to wheels 38 via joints (not shown). According to the present invention, an oil pan 40 of the engine 10 is arranged adjacent the upper enclosure 16a and is integrally formed with the latter. In addition, the upper enclosure 16a is inclined at a predetermined angle in a direction such that the upper portion thereof approaches toward the engine 10, in other words, the upper enclosure 16a is tilted in the direction of the engine. An essentially cylindrical pipe 42 passes through openings formed in both side walls of the oil pan 40 of the engine 10 to be secured to the oil pan 40. The pipe 42 extends so as to be inclined downwards at the same angle as the upper enclosure 16a, from a first end neighboring the final drive unit 14 to the other end thereof. One axle shaft 36a passes through the pipe 42, and the end portion of the axle shaft 36a projected from the oil pan is supported on the oil pan 40 via a bearing 44. Therefore, the axle shaft 36 passes through oil pan 40 to extend so as to be inclined at the same angle as the inclined angle of the upper enclosure 16a. The pipe 42 is preferably arranged at its highest position under conditions such that the pipe 42 does not affect the outermost locus A (in Fig. 3) of the crankshaft, connecting rod and so forth of the engine 10, so that the pipe 42 approaches as near as possible toward the central point O (in Fig. 3) of the engine 10. The inclined angles of the upper enclosure 16a and the axle shaft 36a are limited such that the height of the end portion supported on the oil pan 44 via the bearing 44 does not become lower than the height of the bottom of the lower enclosure 16b, and such that a space in which the bearing 30b is arranged in the upper enclosure 16a does not affect the cylinder block 46 of the engine 10. In addition, a lower link 46 of a suspension system is supported on a vehicular frame 48 so as to be pivotable around an axis 50. As shown in Fig. 1, the pivotal axis 50 of the lower link 46 is arranged at a location behind and below the rotation axis P of the ring-gear 26 and below the upper enclosure 16a of the final drive unit 14. Since the upper enclosure 16a is so inclined that the upper portion thereof approaches the engine 10, the engine 10 can be arranged at a lower position than that of conventional mounting arrangements in which the enclosure of the final drive unit is arranged horizontally. In addition, the pivotal axis 50 of the lower link 46 can be so arranged as to be closer to the central point O of the engine 10 than in conventional mounting arrangements in which the enclosure of the final drive unit is arranged horizontally. Therefore, according to the present invention, it is possible to provide a sufficient length of the lower link 46 without increasing the width of the vehicle body. In addition, it is possible to decrease the angles between the axle shafts 36a and 36b and joints (not shown) arranged on the ends of the lower links 46 of the suspension system. As a result, the height of an engine hood 52 and the width of the vehicular body can not be only decreased, but it is also possible to decrease the camber angle and so forth so as to improve driving stability. In the shown embodiment, though the pivotal axis 50 of the lower link 46 is arranged behind and below the pivotal axis P of the ring-gear 26, it can alternatively be arranged before the latter. In this case, it is also possible to obtain similar effect. In addition, if the pivotal axis 50 of the lower link 46 is not offset from the pivotal axis P of the ring-gear 26 in a longitudinal direction, it is possible to provide a longer lower link 46 than in conventional mounting arrangements. Furthermore, the position of the axle of the final drive pinion 28 is higher than that of the pivotal axle P of the ring-gear 26. A steering rack or relay rod 54 is arranged at a location below the axle of the final drive pinion 28 and before the transmission 12. The joint 32 which transmits the rotation force of the propeller shaft 34 to the final drive unit 14 is arranged at a location before the transmission 12. The diameter of the propeller shaft 34 is less than that of the joint 32, so that the propeller shaft 34 together with the final drive unit 14 can be so arranged as to aproach the central point O of the engine 10. While the shown mounting arrangement is applied to a four-wheel drive vehicle in the embodiment, it can be applied to other front wheel drive types of vehicles.

Claims: A mounting arrangement for an automotive vehicle, comprising: an internal combustion engine; an oil pan (40) arranged beneath the engine and connected to the same, said oil pan having a pair of openings in side walls thereof; an enclosure (16a,16b) for operatively receiving therein a differential case, said enclosure being arranged adjacent to the engine and connected to one of the side walls of said oil pan, said enclosure having a pair of openings which are aligned with the openings of said oil pan; a pair of axle shafts, one of which passes through one of the openings of said enclosure and the other of which passes through the other opening of said enclosure and the openings of said oil pan (40) characterized in that said enclosure is inclined at a predetermined angle to a horizontal plane in a direction in which an upper portion (16a) of the enclosure approaches the engine (10); and said pair axle shafts (36a,36b) have axes inclined at the same angle as that of said enclosure. A mounting arrangement as claimed in claim 1, further characterized in that the other of said pair of axle shafts is rotatably received in a sleeve (42) which extends across said oil pan through the other opening of said enclosure and the openings of said oil pan. A mounting arrangement as claimed in claim 1, further characterized in that the axes of said axle shafts coincide with a rotation axis of said differential case.

Inventors: MURAKAMI SHINICHI, MURAKAMI, SHINICHI
Applicants: NISSAN MOTOR, NISSAN MOTOR CO., LTD.
Application year: 1990
Main classification: B60K5
IPC codes: B60K5, B60K17, F16H48