GB2312474A

GB2312474A - I.c.engine auxiliary drive arrangement

Info

Publication number: GB2312474A
Application number: GB9608440A
Authority: GB
Inventors: John Stephen Williams
Original assignee: MG Rover Group Ltd
Current assignee: MG Rover Group Ltd
Priority date: 1996-04-24
Filing date: 1996-04-24
Publication date: 1997-10-29
Also published as: GB9608440D0

Abstract

A drive member 22 fastened to the crankshaft 14 drives a cam shaft (28, Fig.1), a power steering or air conditioning pump or an alternator. The drive member 22 has a portion 40 mounted between the crankshaft flange 20 and the flywheel 24 and a portion 42 extending from the portion 40 axially of the crankshaft 14 away from the flywheel and over the crankshaft flange. The drive member 22 also has a portion 44 with sprocket or gear teeth 46 or belt grooves for transmitting drive.

Description

AN INTERNAL COMBUSTION ENGINE The invention relates to an internal combustion engine particularly but not exclusively for a motor vehicle and is concerned with a drive for a component such as a cam shaft of the engine taken from one end of a crankshaft.

It has been proposed hitherto to mount a chain sprocket or gear drive arrangement at one end of an engine crankshaft adjacent a flywheel for transmitting drive to a cam shaft or some ancillary machine such as a pump for power assisted steering, an alternator or an air conditioning pump. Invariably, the presence of the gear or sprocket drive increases the length of the engine.

Future crash legislation and packaging requirements for motor vehicles effectively reduce the available space for engines within an engine compartment of a vehicle. Where a transverse engine is used, the constraints can be even greater. Therefore, it is desirable to minimise the length of an engine where possible and an object of the present invention is to provide an internal combustion engine with an improved drive arrangement adjacent the flywheel for driving a component such as a cam shaft.

According to one aspect of the invention there is provided an internal combustion engine having a rotatable crankshaft, a driving flange at one end of the crankshaft, a flywheel connected to the driving flange and a drive member drivable by the crankshaft for driving a component of the engine, the drive member having a first portion mounted between the driving flange and the flywheel and a second portion extending from the first portion axially of the crankshaft away from the flywheel and over the driving 'flange, the second portion having drive means thereon for transmitting drive to the said component.

By arranging for the second portion to extend from the first portion axially of the crankshaft away from the flywheel and over the driving flange1 the drive member does not add significantly to the overall length of the engine.

At the same time, the drive member provides a perfectly satisfactory drive arrangement for, say, a cam shaft of the engine.

Conveniently, the first and second portions of the drive member together form a cup which locates over the driving flange. In that way, the driving flange will actually be positioned within the cup leading to particularly compact arrangement.

The second portion of the drive member preferably has a cylindrical periphery. In such a case, the engine may include a cover member at the flywheel end of the engine which has thereon an oil seal in sealing contact with the cylindrical periphery.

The second portion of the drive member may have an internal groove therein which sealingly locates an oil seal. The oil seal is in sealing contact with the driving flange.

The aforesaid oil seals effectively prevent oil leaking from the interior of the engine at the flywheel end thereof.

Preferably, the flywheel is drivably attached to the driving flange by means of a screw threaded fastener extending through the first said portion of the drive member. In that way, the screw threaded fastener holds both the flywheel and the drive member in position on the driving flange. In practice, several screw threaded fasteners are likely to be used.

The drive member may be formed in one piece, for example, as a metal pressing.

The drive means on the said second portion of the drive member may comprise an annular third portion which extends radially away from the second portion. In such a case, the third portion may take the form of a toothed sprocket for a chain.

An internal combustion engine in accordance with the invention will now be described by way of example with reference to the accompanying drawings in which: Fig 1 shows an internal combustion engine in accordance with the invention partly broken away at one end and showing a drive member drivable by the crankshaft for driving a cam shaft of the engine via chains and Fig 2 is a view of part of the engine shown in Fig 1 and drawn to a large scale, the chains being omitted and the drive member being shown in cross section.

In Fig 1, an engine 10 has a crank case 12 which rotatably supports a crankshaft 14 on a series of co-axial bearings 16, two of which are shown in Fig 1. The crankshaft 14 drives a plurality of pistons 17, one of which is shown in Fig 1, through connecting rods 18 mounted on the crankshaft 14 in known manner.

A driving flange 20 is formed integrally with the crankshaft 14 at the right hand end thereof as viewed in Fig 1. The driving flange 20 carries a drive member 22 in accordance with the present invention which will be described in detail with respect to Fig 2. A flywheel 24 is attached to the driving flange 20 by means of a plurality of bolts 26. The drive member 22 transmits drive to a cam shaft 28 via two endless chains 30, 31.

Looking now at Fig 2, the driving flange 20 is of annular form having an annular right hand surface 32 and a cylindrical outer surface 34. The crankshaft 14 terminates at a cylindrical projection 36 for locating an internal diameter 38 of the flywheel 24. The projection 36 on the crankshaft 14 houses a pilot bearing 37 in which one end 39 of a gearbox main shaft is rotatably mounted.

It will be seen that the drive member 22 is cup like and of top hat cross-section having an annular first portion 40, a cylindrical second portion 42 extending from the first portion 40 over the driving flange 20 and away from the flywheel 24, and an annular radially extending third portion 44 which is formed with sprocket teeth 46 for the chain 30 (Fig 1). The annular first portion 40 fits slidably over the projection 36 and the cylindrical second portion 42 fits slidably over the cylindrical outer surface 34 of the driving flange 20. The second portion 42 is formed with an internal peripheral groove 48 which sealingly locates an oil seal 50. The oil seal 50 is in sealing contact with the cylindrical outer surface 34 of the driving flange 20.

The annular first portion 40 of the drive member 20 is formed with an aperture 52 which aligns accurately with a bore 54 in the driving flange 20 and with a bore 56 formed in the flywheel 24. A location dowel 58 locates accurately in the aperture 52 and the bores 54, 56. The annular first portion 40 is also formed with a plurality of further apertures 60 (one only of which is shown) which align with respective screw-threaded bores 62 in the driving flange 20 and bores 64 in the flywheel 24. The fixing bolts 26 pass through the bores 64 and through the apertures 60 in the first portion 40 of the drive member 22. The bolts 26 screw into the screw-threaded bores 62 in the driving flange 20 so as to bolt the flywheel 24 in position on the driving flange 20 with the first portion 40 of the drive member 22 sandwiched therebetween.

The drive member 22 may be formed as a one piece metal pressing or can be machined from solid.

A cover member 70 for the right hand end of the engine 10 is formed with an opening 72 coaxial with the crankshaft 14. The opening 72 carries an oil seal 74 which makes sealing contact with a cylindrical outer periphery of the drive member second portion 42. The seals 50, 74 inhibit leakage of oil from the inside of the engine 10.

Whilst specific reference has been made to the drive member 22 driving the cam shaft 28, it can be used to drive other components such as a power assisted steering pump, an alternator or an air conditioning pump. In place of sprocket teeth 46, the drive member may be formed other drive means such as gear teeth for a gear drive or with teeth or grooves for a belt drive. More than one drive means may be provided on the drive member 22.

The way in which the flywheel 24 is mounted in Fig 2 is also particularly advantageous as the driving flange 20 provides an ideal mounting for the flywheel 24 dispensing with the need for a conventional taper 84 on the crankshaft 14 which requires a large central securing bolt coaxial with the crankshaft 14.

Claims

1. An internal combustion engine having a rotatable crankshaft, a driving flange at one end of the crankshaft, a flywheel connected to the driving flange and a drive member drivable by the crankshaft for driving a component of the engine, the drive member having a first portion mounted between the driving flange and the flywheel and a second portion extending from the first portion axially of the crankshaft away from the flywheel and over the driving flange, the second portion having drive means thereon for transmitting drive to the said component.

2. An internal combustion engine according to Claim 1 in which the first and second portions of the drive member together form a cup which locates over the driving flange.

3. An internal combustion engine according to Claim 1 or 2 in which the second portion of the drive member has a cylindrical periphery.

4. An internal combustion engine according to Claim 3 in which the engine includes a cover member at the flywheel end of the engine, the cover member having thereon an oil seal which is in sealing contact with the cylindrical periphery of the said second portion of the drive member.

5. An internal combustion engine according to any preceding claim in which the second portion has an internal groove therein which sealingly locates an oil seal in sealing contact with the driving flange.

6. An internal combustion engine according to any preceding claim in which the flywheel is drivably attached to the driving flange by a screw-threaded fastener which extends through the first said portion of the drive member.

7. An internal combustion engine according to any preceding claim in which the drive member is formed in one piece.

8. An internal combustion engine according to any preceding claim in which the drive means on the second portion of the drive member comprises an annular third portion which extends radially from the second portion.

9. An internal combustion engine according to any preceding claim in which the drive means is a sprocket for a chain.

10. An internal combustion engine constructed and arranged substantially as described herein with reference to Figs 1 and 2 of the accompanying drawings.