GB2183572A

GB2183572A - Mounting arrangement for a drive unit in a vehicle

Info

Publication number: GB2183572A
Application number: GB08620921A
Authority: GB
Inventors: Frank Giebel
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1985-12-06
Filing date: 1986-08-29
Publication date: 1987-06-10
Also published as: GB8620921D0; FR2591156B1; DE3543167A1; FR2591156A1; DE3543167C2; GB2183572B

Abstract

An arrangement is described for mounting a drive unit in a motor vehicle, the drive unit comprising an internal combustion engine and a transmission. The drive unit (1) is supported by a first pair of resilient mountings (13, 14) on an engine cross member (15) which is in turn supported on the vehicle bodywork by way of a second pair of resilient mountings (16, 17). The first resilient mountings (13, 14) lie on a first line (V1) extending transversely to the axis of the engine crankshaft, and the second resilient mountings (16, 17) lie on a second line (V2) inclined at an acute angle to the first line (V1) and to the axis (18) of the engine crankshaft. By virtue of this geometry, engine vibrations cause compression of the mountings (13, 14, 16 and 17), while torque reactions apply torsional stresses to the second resilient mountings (16, 17). <IMAGE>

Description

SPECIFICATION Mounting arrangement for a drive unit The invention relates to a mounting arrangement for mounting a drive unit in a motor vehicle, the drive unit comprising an internal combustion engine and a transmission, in which mounting arrangement the drive unit is supported by a first pair of resilient mountings on an engine cross memberwhich is in turn supported on the vehicle bodywork by way of a second pairof resilient mountings.

A mounting arrangement of a drive unit in a motor vehicle of the type described above is known from German Auslegeschrift22 32 102, in which the drive unit, which comprises an internal combustion engine with a flange-mounted clutch and gearbox unit, is supported by two first mountings on an engine cross member, in turn supported byway oftwo second resilient mountings on the bodywork, and at a third point on the bodywork by a further resilient mounting.

In the case of this known mounting arrangement of adrive unitthethird point is supported onthe bodyworkbywayofa resilient mounting own a gearbox cross member which is in turn supported on the bodywork byway of two still further resilient mountings. In accordance with afurtherembodimentthe engine cross member is constructed in the form ofaframesupport integrally with the gearbox cross member.

This known mounting arrangement of a drive unit is consequently relatively complicated and expensive and it requires considerable structural space.

A mounting arrangement of a drive unit in a motor vehicle is known from the German Offenlegungsschrift 30 35 943, in which the drive unit is sup ported on the bodywork by way ofthree engine mountings on the one hand and byway oftwo gearboxsupport mountings on the other hand.

In this known mounting arrangement of a drive unit the high-frequency vibrations ofthe internal combustion engine areto be absorbed byengine mountings made suitablyyielding,whereasthe torque reactions on the gearbox unit are absorbed by gearbox mountings made appropriately more stiff.

Amounting arrangementofa drive unit in a motor vehicle is also known from German Offenlegu ngsschrift 3402 100, in which the drive unitcompris- ing a transversely mounted engine and a clutch and gearbox unit is supported on the bodywork byway ofthree resilient mountings which are made re iativelyyieiding, the torque reactions of the transmission unit being absorbed by way of two additi onal torque supports.

In the case of this known mounting arrangement of a drive unit in a motorvehicle, the structural outlay is again relatively substantial.

According to the present invention, there is provided a mounting arrangement for mounting a drive unit in a motorvehicle, the drive unit comprising an internal combustion engine and a transmission, in which mounting arrangement the drive unit is supported bya first pairof resilient mountings on an engine cross member which is in turn supported on the vehicle bodywork by way of a second pair of resilient mountings, wherein the first resilient mountings lie on a first line extending transversely to the axis ofthe engine crankshaft, and the second resilient mountings lie on a second line inclined at an acute angleto thefirst line and to the axis ofthe engine crankshaft.

By virtue ofthis construction, the high-frequency vibrations arising in the internal combustion engine and acting essentially vertically are absorbed in a yielding manner both bythefirstand bythesecond resilient mountings, whereas the low4requency rolling motion of high amplitude caused by torque reactions ofthe drive unit is absorbed only in the form of torsional stresses of the first resilient mountings.

More particularly, becausethe lineconnectingthe first mountings extends transversely ofthe axis of the crankshaft,the engine vibrations apply equal vertical pressue to both the first mountings and these in turn apply equal vertical pressureto the second resilient mountings. On the other hand, because ofthe inclination ofthe line passing through the second resilient mountings, when unequal downward pressure is applied to thefirst mountings as a result of torque reaction in the transmission, a torque is applied tending to twist the engine cross member about the line passing through the second mountings and these are loaded in torsion.The engine mountings can thus now be designed with different stiffnesses in compression and torsion so asto allowthemto absorb both types of loading efficiently and suppress both engine vibration and torque reactions.

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 isadiagrammaticviewofthemounting arrangement of a drive unit as viewed in the direction oftravel of a motor vehicle, Figure2 is a plan view of the mounting arrangement of a drive unit in Figure 1, Figure 3 is a side view of the mounting arrangement according to Figure 1, Figure4isafurtherembodimentofa mounting arrangement of a drive unit arranged in the longitudinal direction of the vehicle, and Figure 5 is a further embodiment of a mounting arrangement of a drive unit arranged in the transverse direction ofthevehicle.

Figures 1 to 3 diagrammatically illustrate a drive unit 1 which comprises an internal combustion engine 2 and transmission 3. The transmission 3 includes a clutch 4, a change-speed gearbox 5 and a differential gear 6. Drive shafts 7 and 8 lead from the differential gear 6 to the driven front wheels (not shown).

The drive unit 1 is supported on the bodywork in the region ofthe engine compartment which is framed by two longitudinal members 9 and 10, a front cross member 11 and a rear cross member 12.

The drive unit 1 is supported byway ofafirst pair of resilient mountings 13 and 14on an engine cross member 15, the ends ofwhich are supported on the front and rear cross members 11 and 12 respectively by way of a second pair of resilient mountings 16 and 17. The line V1 passing through the first pair of re silientmountings 13 and 14extendsatapp- roximately 90" to the crankshaft axis 18 of the internal combustion engine and through the centre of gravity S of the drive unit 1.The line V2 passing through the second pair of resilient mountings 16 and 17 extends at an acute angleto the line Va and also passes through the centre of gravity S ofthe drive unit 1.

Thethird pointofthe drive unit 1 is supported on a longitudinal member10 bywayofa known engine support mounting 19.

On account of this special mounting arrangement, in the event of vertical high-frequency vibrations caused bythe internal combustion engine 2, the mountings 13 and 14aswell as 16 and 17together with the mounting 19 are acted upon in phase. In accordance with the lever ratios theforces are trans mitted to the second resilient mountings 16 and 17 byway ofthe engine cross member 15. All four resilient mountings are acted upon with downward pressure.

In the event of rolling motion ofthedrive unit 1 caused by a starting or braking torque reaction of the drive unit 1 one of the two mountings 13 and 14is subjected to increased pressure and the othertore- duced pressure.

In this way a moment is produced about the axis of the mountings 16 and 17 as a result ofthe different downward forces acting through the distances a and b, these being the distances from the mountings 13 and 1 4to the line V2. This torque rotates the cross member 15togetherwith the drive unit 15 aboutthe line V2. In this case the second resilient mountings 16 and 17 are stressed in torsion.

On account of the fact that the engine vibrations give rise to compression stresses in the mountings whereas reaction torque gives rise to torsion stresses in the mountings it is possibleforthe mountings to be designed with differentstiffnesses for the different loads to which they are subjected.

Thus, for the high-frequency vertical vibrations, the mountings can be made relatively yielding in the direction of pressure, whereas they can be made re latively stiff in the torsional direction forthetorque reactions.

Figure 4 shows the mounting arrangement of a drive unit in a motorvehicle, in which the drive unit is fitted in a known manner in the longitudinal direction ofthevehicle and is connected to a differential in the rear axle drive by a shaft fitted with universal joints.

The corresponding components of the drive unitand ofthe mounting arrangement have been allocated the same reference numerals with the addition of a prime and need not be described again in detail. In this case the mode of operation corresponds to the mode of operation as described in connection with Figures 1 to 3.

In the event of vertical vibrations all four mountings are loaded in compression, while in the event of rolling motion the mountings 16' and 17' are loaded in torsion. The mounting arrangement 19' on the gearbox extension corresponds to a conventional engine support mounting at this position.

Figure 5 again shows a mounting arrangement in which the drive unit is fitted transversely to the longitudinal direction ofthevehicle.The components differing from the embodiment according to Figures 1 to 3 have been given the same reference numerals provided with a double prime in each case.

The difference between this embodiment and that of Figures 1 to 3 is that instead of a conventional en ginesupportmounting 19 a second engine cross member 20 is provided, on which the drive unit 2,4,5 and 6 is supported by way offirst resilient mountings 22 and 23 and which is supported on the bodywork byway of second resilient mountings 24 and 25. The lines of action of the first and second resilient mountings again extend along the connection lines V1 and V2 which are arranged according to the invention.

The mode of operation is as explained in connection with Figures 1 to 3.

Claims

1. A mounting arrangement for mounting a drive unit in a motor vehicle, the drive unit comprising an internal combustion engine and a transmission, in which mounting arrangement the drive unit is supported bya first pairof resilient mountings on an en ginecrossmemberwhich is intern supported on the vehicle bodywork by way of a second pair of resilient mountings, wherein the first resilient mountings lie on a first line extending transversely to the axis of the engine crankshaft, and the second resilient mount- ings lie on a second line inclined at an acute angleto the first line and to the axis of the engine crankshaft.

2. A mounting arrangement as claimed in claim 1, wherein the drive unit is supported at three points within the vehicle engine compartment, the firsttwo points being constituted by the said first pair of resilient mountings and the third point being constituted by a further resilient mounting supporting the drive unit directly on the vehicle bodywork.

3. A mounting arrangement as claimed in claim 1, wherein the drive unit is mounted transversely within the engine compartment and is supported at each end on a respective cross member, each cross member being connectedtothe engine byfirst resilient mountings lying on a line transverse to the engine crankshaft and being connected to the vehicle bodywork by two second resilient mountings lying own a line inclined to the axis of the engine crankshaft and to the line passing through the first resilient mountings.

4. A mounting arrangement constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in Figure 1 to 3, Figure 4 or Figure 5 oftheaccompany- ing drawings.