GB2222124A

GB2222124A - Vehicle engine and differential gear arrangement

Info

Publication number: GB2222124A
Application number: GB8915050A
Authority: GB
Inventors: Akio Kazama
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1988-06-29
Filing date: 1989-06-29
Publication date: 1990-02-28
Anticipated expiration: 2009-06-29
Also published as: GB2222124B; GB8915050D0; JPH0211418A; JPH0474213B2; DE3921414A1; DE3921414C2

Description

C'; 0) f) -, r) 2 22 2 1, 4 1 - DRIVE SYSTEM FOR VEHICLE 1 This invention

relates to a drive system for a vehicle wherein the engine is oriented longitudinally of the vehicle (i.e., with its crankshaft being disposed parallel to the longitudinal direction of the vehicle) and is adapted to drive left and right drive wheels which are located opposite lateral sides of the engine.

a on The present invention is applicable to either an arrangement where the engine is disposed at the front part of the vehicle and drives left and right front wheels or an arrangement l0where the engine is disposed at the rear part of the vehicle to drive left and right rear wheels.

It is conventionally known for a power plant to be -ial device comprised of an engine, a transmission and a differen4L in a single unit disposed in the longitudinal direction of the 15vehicle with the output of the power plant transmitted to lateral drive wheels via an intermediate transmission shaft which penetrates through and is carried by the power plant such as in Japanese Patent Publication Kokoku No. 48-13015, U.S. Patent 3,494,225, British Patent 1,032,090, German Patent 1,555,101.

2 - In one such conventional structure, i.e. Japanese Publication No. 4813015, however, the cylindey block, the oil pan and the differential case for the differential device are formed separately from each other so that an accumulation of tolerances generated in these three components makes it difficult to assemble them together with accuracy, which may undesirably lead to the occurrence of gouging on their assembled surfaces at the time of assembly and galling or scratching on a rotary shaft and like elements which are mounted to extend between these components. In order to eliminate these inconveniences, the working accuracy of each component has to be enhanced greatly but this causes an increase in manufacturing cost. Moreover, a large number of parts are required so that their assembling cost increases and the rigidity at joined portions of the engine may be decreased.

The present invention has been accomplished in view of the abovementioned circumstances and its object is to provide a novel drive system for a vehicle which allows the assembling accuracy and joining rigidity of the engine to be improved and also enables the system to be manufactured at a decreased cost.

3 According to the invention there is provided a drive system for a vehicle provided with an engine, a transmission and a differential devi ce with the engine oriented with its crankshaft extending longitudinally of the vehicle for driving left and right wheels disposed on opposite sides of the engine, wherein said engine has a cylinder block with a cylinder axis inclined in one of either the left or right direction of the vehicle, an oil pan joined to the cylinder block with joining surfaces thereof in a plane perpendicular to said cylinder axis and below a center plane passing through the center of rotation of the engine crankshaft, and wherein said differential device is contained within a differential case body which is integrally formed with the cylinder block on a side of said cyLinder block on the side of inclination of the engine, and an intermediate transmission shaft extending through and being supported by said cylinder block and said oil pan for operatively connecting said differential device and one said drive wheel located on the opposite side of the engine fran the differential device. N With such an arrangement, the engine serving as a power source portion of the power plant may have a fewer number of parts than the prior art since the cylinder block and the differential case are formed integrally with each other and therefore it has a high strength at the integrally joined portions as well as high assembling accuracy between the remaining parts thereof.

- 4 An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, wherein:

Fig. 1 is a schematic plan view of a vehicle in s which a drive system according to the invention is provided; Fig. 2 is an enlarged sectional elevation view taken along a line II - II in Fig. 1; Fig. 3 is an enlarged sectional plan view taken along a line III - III in Fig. 2; Fig. 4 is a side view taken in the direction of a line IV - IV in Fig. 2; and k is Fig. 5 is a sectional plan view, with a portion as a schematic view of a drive line for the balancer shafts, taken along a line V - V in Fig. 2.

Referring now to Fig. 1, a power plant P which is comprised of an engine 1, a clutch 2, a transmission 3 and a differential device D as a unit is mounted on a vehicle V in the longitudinal direction thereof (with a crankshaft 5 of the engine 1 being directed parallel to the longitudinal axis of the vehicle V) and the output of the power plant is transmitted through universal joints it,, Jrj, drive shafts St, Sr, and universal joints J1P, JrV to front wheels Wt, Wr as left and right drive wheels, respectively.

As shown in Figs. 2 and 3, the engine 1 of the power plant P has a cylinder axis L, - L, set at an inclination (about 45) in one of the left or right directions of the vehicle V with respect to the vertical line (to the right side in the travelling direction of the vehicle V in this illustration) and a cylinder head 7 with a head cover 8 atop the head 7 are superposed and connected onto an upper surface of the cylinder block 6. The cylinder block 6 includes a skirt portion 61 constituting a crankcase area which is joined at its lower surface with an oil pan 13 by means of a plurality of connection bolts 11. The joining plane P1 - P1 of the surfaces of the skirt portion 61 and 1 6 - the oil pan 13 are on an inclined plane extending across the cylinder axis LI - Ll at right angles and parallel to but below a I crank center plane P2 - P2 which passes through the center 0 of the journal bearings 10 for supporting the journal shaft portion of the crankshaft 5. The journal bearings 10 are comprised of a bearing half 15 formed within the crankcase portion 61 of the cylinder block 6 and a bearing cap 16 coupled to the bearing half 15, and each journal shaft portion of the crankshaft 5 is rotatably carried by one of these journal bearings 10. The journal bearing 10 is positioned above the joining plane Pl- P, between the skirt portion 61 and the oil pan 13.

A differential case body 17, for containing the differential device D therein is integrally formed on the outside surf ace of the skirt portion 6, of the cylinder block 6 on the inclined side of the engine 1. A differential case cover 172 is f ixed to an open end f ace of the dif f erential case body 171 by bolts 18 thereby forming a differential case 17 of an enclosed and rigid structure.

That part of the skirt portion 61 of the cylinder block 6 which is on the side of the differential case 17 and the oil pan 13 have an intermediate transmission shaft 12 extending horizontally therethrough and the intermediate transmission shaft 12 lies below the crankshaft 5 and crosses it substantially P j 7 - perpendicularly. The shaft 12 is rotatably supported at one end portion thereof (the right end portion in Fig.,2) on a bearing 6 holder 19 formed on the oil pan 13 via a ball bearing 24.

The other end portion (the left end portion in Fig. 2) of the intermediate transmission shaft 12 extends through the skirt portion 61 of the cylinder block 6 which serves as a partition wall between the crankcase and the differential case 17, and said other end portion is carried rotatably on that skirt portion 61 via a tapered roller bearing 21. That end of the intermediate transmission shaft 12 which projects into the differential case 17 is spline-connected to a pinion drive gear of the differential device D.

As has been described above, the differential device D is arranged in a dead space provided below the inclined cylinder block 6, thus permitting the whole power plant P to be very compact. The differential device D is constructed in a conventionally known manner and comprises a differential housing supported rotatably on the differential case 17 by means of tapered roller bearings 21, 22, a driven gear 26 of a large diameter fixed to the outer periphery of the differential housing and operatively connected to a propeller shaft 4 which extends from the transmission 3, a pair of differential pinion gears 28, 29 carried by a pin 27 on the differential housing 25, and a pair of pinion drive gears 30, 31 meshed with the differential pinion gears 28, 29. One pinion drive gear 30 is spline-connected to the inner end of the intermediate transmission shaft 12 as mentioned above and the other pinion drive gear 31 is spline-connected to the universal joint Jrj.

The inner end of the universal joint ir, is rotatably supported on the outer wall of the differential case 17 via the tapered roller bearing 22 and the universal joint ir, is in turn coupled at the outer end thereof to the right-hand drive wheel Wr through the drive shaft Sr and the other universal joint ir 2 as shown in Fig. 1. The outer end of the intermediate transmission shaft 12 is spline-connected with the inside end of the universal joint JR-, whereas the outside end of the universal joint JP1, is coupled to the left-hand drive wheel Wt through the drive shaft SP- and the further universal joint J1. as shown in Fig. I.

The reference numerals 32, 33, 34 and 35 designate oil seals at the required locations to prevent external leakage and leakage between the crankcase and the differential.

As shown in Figs. 2 and 5, a pair of balancer shafts 36, 37 are rotatably supported in the crankcase of the cylinder block 6 on opposite sides of the crank shaft 5 in a manner parallel to the latter and these balancer shafts 36, 37 are provided with a pair of weights 36W, 36W and 37W, 37W, _k 7 j respectively. The pair of balancer shafts 36 and 37 are operatively connected to the crankshaft 5 via a timing transmission device 38.

The timing transmission device 38 comprises a drive pulley 39 fixed to the crankshaft 5, a first driven pulley 40 fixed to one balancer shaft 36, a second driven pulley 41 M rotatably carried on the skirt portion 61 of the cylinder block 6 adjacent and parallel to the other balancer shaft 37, an endless timing belt 42 wound around the drive and driven pulleys 39 and 40 and 41, a drive gear 44 fixed to an intermediate shaft 43 adjacent the second driven pulley 41 and a driven gear 45 fixed to the other balancer shaft 37 and placed in mesh with the drive gear 44. In this device, the number of teeth of the first and second driven pulleys 40 and 41 are equal to one half the number of teeth of the drive pulley 39 whereas both the gears 44 and 45 have the sane number of teeth. Thus,' the balancer shafts 36 and 37 are rotated in opposite directions at twice the speed of rotation of the crankshaft 5 during rotation of the latter and the sum of the centrifugal forces obtained by the weights 36W and 37W serves to negate the secondary force of inertia of the reciprocating mass of the engine I.

When the engine 1 of the power plant P is operated, its output is transmitted from the clutch 2 and the transmission 3 - cl through the propeller shaft 4 to the differential device D and then from the device D to the left-hand drive wheel WZ through I the intermediate transmission shaft 12, universal joint JZ1, drive shaft St and further universal joint JZ 2 and also from the differential device D to the right-side drive wheel Wr through the universal joint irl, drive shaft Sr and further universal joint J.r2.

Since the engine 1 as the power source portion of the power plant P is integrally formed with the differential case body 17, on its cylinder block 6, the number of parts is reduced to enhance the joining rigidity of the whole engine 1 and improve the assembling accuracy of the parts.

Moreover, since the plane on which the bearing half 15 and the bearing cap 16 are joined to each other crosses the cylinder axis L, - L, perpendicularly and lies on the above-described crank center plane P2 _P2f even though there is an inclined arrangement of the cylinder block 6, the explosion load produced during operation of the engine 1 acts on the joined surfaces of the bearing half 15 and the bearing cap 16 almost vertically and therefore no slip occurs between the surfaces.

Furthermore, due to the arrangement whereby the joining plane P1 - Pi between the cylinder block 6 and the oil pan 13 is located below the crank center plane P2 - P2. the skirt portion -1 4 R 61 can be formed long and contributes by its integral formation with the differential case 17 to further imprpVing the rigidity of the structure.

In addition, the arrangement whereby the cylinder axis Lj- L, of the engine 1 is inclined toward one lateral side allows the total height thereof to be reduced to lower the center of gravity. The disposition of the differential device D on the -1e side of the engine 1 as the inclined side thereof enables the width of the power plant P in the direction normal to the crankshaft 5 to be reduced to a minimum, thereby making it compact.

N1rq It is to be clearly understood that there are no particular features of the foregoing specification, or of any claims appended hereto, which are at present regarded as being essential to the performance of the present in-\,7ention, and that any one or more of such features or combinations thereof may therefore be included in, added to, omitted from or deleted from any of such claims if and when amended during the prosecution of this application or in the filing or prosecution of any divisional application based thereon. Furthermore the manner in which any of such features of the specification or claims are described or defined may be amended, broadened or otherwise modified in any manner which falls within the knowledge of a person skilled in the relevant art, for example so as to encompass, either implicitly or explicitly, equivalents or generalisations thereof.

0 12 -

Claims

CLAIMS:

1. A drive system for a vehicle provided with an engine, a transmission and a differential device with the engine oriented with its crankshaft extending longitudinally of the vehicle for driving left and right wheels disposed on opposite sides of the engine, wherein said engine has a cylinder block with a cylinder axis inclined in one of either the left or right direction of the vehicle, an oil pan joined to the cylinder block with joining surfaces thereof in a plane perpendicular to said cylinder axis and below a center plane passing through the center of rotation of the engine crankshaft, and wherein said differential device is contained within a differential case body which is integrally formed with the cylinder block on a side of said cylinder block on the side of inclination of the engine, and an intermediate transmission shaft extending through and being supported by said cylinder block and said oil pan for operatively connecting said differential device and one said drive wheel located on the opposite side of the engine fran the differential device.

2. The drive system according to claim 1, wherein one end of said intermediate transmission shaft is supported by said oil pan and the other end of said intermediate transmission shaft is supported by said differential case body of the cylinder block.

a

3. -o claim 1 or 2, wherein a Thp. drixre system according t bearing means is provided in said oil pan and another bearing means is provided in said differential case for providing said support of the one end and other end of the intermediate transmission shaft.

4. The drive system of claims 1, 2 or 3, wherein said oil pan is comprised of an integral closed case having an open upper end with one of said joining surfaces for mounting directly to the cylinder block and a closed bottom for containing engine oil.

5. A drive system for a vehicle, substantially as hereinbefore described with reference to the accompanying drawings.

Published 1290 atThe PatentOffice, State House, 88.7 t H41i Holburn, London WClR4TP- Further copies ma_V be obtainedfroniThe Patent Offios. SlIes Branch, St Mary Cray, Orpington, K2nt BR5 3RD. Printed by Multiplex tecbniques ltd, St Mary Cray. Kent, COn- V87