GB2043208A - A disc forming a drive coupling - Google Patents

Abstract

A drive coupling for connecting an internal combustion engine to a hydrokinetic torque converter comprising a disc (10) of sheet steel or reinforced plastics material carrying a starter ring gear (14) on its peripheral edge and adapted to be bolted to a drive shaft at its central region (11, 12) and to the torque converter at its peripheral region (13) has corrugations extending in the peripheral direction. <IMAGE>

Description

SPECIFICATION Drive coupling This invention relates to drive couplings. Internal combustion engines are often connected to hydrokinetic torque converters by a drive coupling in the form of a thin resilient steel disc produced as a pressed piece. This disc is firmly attached by screws to the crankshaft in its central region and to the converter housing in its external region and carries a starter ring gear on its external circumference.

A vibration-damping drive coupling of this type is disclosed in German Patent Publication No. 1 134 865. The drive coupling disclosed therein comprises a thin, resilient, plate-shaped steel disc, which is constructed as a simple pressed piece, and is capable pf bridging slight alignment errors and axial tolerances between the crankshaft of the internal combustion engine and the housing of the torque converter. In order to damp noisy resonance vibrations caused by the actuation of the starter fingers are stamped clear out of the steel disc and bent axially to co-operate resiliently and frictionally with the external surface of the axially extending part of the converter housing.

As a result of the arrangement of the clear stamped and axially bent fingers and their bracing against the converter housing, and of the construction of the external region of the thin resilient drive disc as a rigid, bead-shaped envelope surface, the known drive disc is substantially capable of damping only the radial vibrations originating from the starter actuation and their resonance phenomena.

Furthermore, the pot-shaped or plate-shaped thin resilient drive discs hitherto known were also capable of transmitting the rotary vibrations which ultimately occur with every internal-combustion engine.

Due to the development of internal-combustion engines towards higher efficiency which is currently required, i.e., towards higher specific power, it has been discovered that the hitherto known dishshaped or plate shaped resilient drive discs were no longer capable of establishing a reliable driving connection between the crankshaft of the internalcombustion engine and the torque converter in the face of the rotary vibrations which now become increasingly apparent. With internal-combustion engines having substantial rotary vibrations, premature fractures of the thin resilient drive discs were repeatedly suffered, or if the latter were correspondingly reinforced, considerable damage to the internal combustion engine or to the torque converter occurred after a relatively short time due to the rigid undamped transmission of the rotary vibrations.

For specific internal-combustion engines with such rotary vibration problems it was hitherto necessary to arrange an appropriate rotary vibration damper on the crankshaft in order to ensure a reliable driving connection between the internalcombustion engine and the torque converter.

However, the arrangement of such a rotary vibration damper, known perse in its construction, on the crankshaft of the internal-combustion engine repre sented a substantial cost outlay from both stand points of assembly and of components.

According to the present invention there is pro vided a drive coupling for connecting an internal combustion engine to a hydrokinetic torque conver ter comprising a disc adapted to be firmly attached by bolts to an engine crankshaft in its central region and to a converter housing in its external region and carrying a starter ring gear on its external circumfer ence, characterised in that the drive disc exhibits corrugations extending in the radial direction.

Preferably the drive disc is produced as a pressed piece in the form of a disc corrugated in the peripheral direction and the height and lengths of the corrugation desirably increase e.g., from-the inside outwards. Advantageously, the fixing points to the converter housing and to the starter ring gear are arranged so that at least one corrugation decliv ity lies between two corresponding fixing points, thus allowing a slight elastic relative movement of the hole pattern of the inner fixing points to the hole pattern of the outer fixing points in the peripheral direction. Rotary vibrations are thereby damped by elastic deformation work of the material of the drive disc.

It is not always possible from structural considerations to construct a vibration-damping drive disc in the conformity with the- ideal of a disc corrugated in the peripheral direction. In such cases it has been found convenient for the drive disc according to the invention to be constructed with sector-shaped or parallel walled pockets merging with appropriate curvatures into the disc plane in the region of the fixing points to the converter hosuing, the depth of which in the radial and axial directions can be dimensioned differently in conformity with the rot ary vibrations occurring and with the material used for the drive disc. In this case the rounded pocket walls located in the peripheral direction assume the resilient function of the corrugation declivities.

The invention is explained more fully with refer ence to two exemplary embodiments illustrated in the accompanying drawing, wherein: Figure 1 shows an elevation of a drive disc in its installation position between the crankshaft of the internal-combustion engine and the converter hous ing of the torque converter; Figure 2 shows an elevation of an idealised drive disc with a starter ring gear attached to it; Figure 3 shows a section made along the line Ill-Ill in Figure 2; Figure 4 shows a section made in the peripheral direction along the line IV-IV in Figure 2; Figure 5 shows an elevation of a structurally executed drive disc; Figure 6 shows a section made along the line VI-VI in Figure 5 and Figures 7 + 8 show views of the pockets in the direction of the arrows VII and VIII in Figure 5.

In Figure 1, the crankshaft 1 of an internal combustion engine is connected by a thin resilient drive disc2, produced as a pressed piece, to the converter housing 3 of a torque converter, e.g., of an automatic transmission.

It is pointed out that obviously other suitable prime movers and transmission arrangements may be connected by a drive disc of this type. Thus the crankshaft of an internal-combustion engine may be replaced by the eccentric shaft of a rotary power engine, and a hydraulic coupling or another input member of a transmission arrangement may replace a torque converter.

Figures 2 to 4 illustrate an idealised embodiment of a drive disc 10. The drive disc 10 exhibits a central bore 11 by which it can be centred on the drive shaft of the engine. By a plurality of inner bores 12 the drive disc 10 can be connected firmly against friction and rotation by screws (not shown) to a flange of the drive shaft. In the external region of the drive disc 10, external bores 13 are provided at equal intervals, by which the drive disc 10 can be connected firmly against friction and rotation by screws (not shown) to the converter housing of a torque converter (not shown). A starter ring gear 14 is arranged on the external circumference of the drive disc 10 and connected to the drive disc 10 by spot welds 15. The drive disc 10 may be provided with radial stops 16 and axial stop tongues 17 for the centering and axial anchorage of the starter ring gear 14.

As may be seen more particularly from Figure 4, the surface of the drive disc la between the internal bores 12 and the external bores 13 extends in uniform corrugations 20 extending in the peripheral direction and forming corrugation ridges 18 and corrugation troughs 19. It is necessary to construct plane contact surfaces 21 in the region of the external bores 13 on the corrugation ridges 18.

In order to ensure optimum functioning of the vibration-damping drive disc 10 it is important that the external fixing points 13forfixing to a converter housing are arranged respectively on consecutive or alternate corrugation ridges 18 and the fixing points 15 for fixing to the starter ring gear 14 in an intervening corrugation trough 19 or an intervening corrugation ridge 18. In this manner it is ensured that at least one corrugation declivity, preferably two corrugation declivities, permit an elastic deformation in the peripheral direction and thus ensure a damping of rotary vibrations by elastic deformation work by an oscillating elastic relative movement of the inner hole pattern of the fixing points 12 to the outer hole pattern of the fixing points 13.

Figures 5 to 8 illustrate a practical drive disc which has already given satisfactory results in internal trials.

Athin resilient drive disc 100 produced as a pressed piece is again provided with a central or centering bore 111 and exhibits in its central plane region internal bores 112 for fixing to the crankshaft ofthe internal-combustion engine, and in its external region external bores 113 for fixing to the converter housing of a torque converter. The drive disc 100 is constructed substantially plane in this case, provided in the region of the bores 113 for fixing to the converter housing with sector-shaped pockets 200 which extend inwards over approximately 2/3 of the radius of the drive disc 100 and are embossed trapezoidally in a tangential section. The depth of the pockets 200 in both the radial and axial directions can be varied within wide limits.As may be seen from figures 7 and 8, it may be convenient to provide different sets of pockets 200 or 200' of different depth.

It is pointed out that the walls of the pockets need not necessarily be aligned in sector-shaped conformation to the centre of the drive disc. Said walls may on the contrary likewise extend mutually parallel or diverge towards the centre of the drive disc. The only essential feature is that the axial and radial depth of the pockets and their curvatures to the remaining disc plane are dimensioned in conformity with the stresses occurring.

Depending upon the existing installation conditions for the drive disc, it may be necessary for the pocket plane to coincide with the disc plane. In this case the pocket walls may be joined to the two surfaces lying in one plane by S-shaped curvatures.

Attention is also drawn to the fact that the drive disc according to the invention can not oniy be constructed as a metal disc, but that on the contrary the future use of plastics materials reinforced with glass fibres or graphite fibres for such drive discs has already been foreseen.

Claims (9)

1. A drive coupling for connecting an internal combustion engine to a hydrokinetic torque converter comprising a disc adapted to be firmly attached by bolts to an engine crankshaft in its central region and to a converter housing in its external region and carrying a starter ring gear on its external circumference, characterised in that the drive disc exhibits corrugations extending in the radial direction.

2. A drive coupling according to claim 1 wherein the drive disc is adapted to be attached to the converter housing at points aligned with ridges of consecutive or alternate corrugations and to the crankshaft at points aligned with intervening troughs or ridges.

A drive coupling according to claim 1 or claim 2 wherein the disc is fixed to the starter ring gear at points arranged in the intervening troughs or ridges.

4. A drive coupling according to any one of claims 1 to 3 wherein the corrugations extending in the peripheral direction are constituted by pockets constructed in the region of the fixing points to the converter housing.

5. A drive disc according to any of claims 1 to 3 wherein the corrugations extend in fan-shaped configuration from the inside outwards growing wider across the entire disc plane.

6. A drive coupling according to any one of claims 1 to 5 wherein the drive disc is composed of sheet steel.

7. A drive coupling according to claim 6 wherein characterised in the starter ring gear is centred radially on the external circumference of the drive disc and is axially anchored by stop tongues and fixed by welding.

8. A drive coupling according to any one of claims 1 to 5 wherein in that the drive disc is composed of a fibre-reinforced plastics material and the starter ring gear is shaped integrally thereon.

9. A drive coupling substantially as hereinbefore described with reference to the drawings.