GB2323425A

GB2323425A - Flywheel device

Info

Publication number: GB2323425A
Application number: GB9814352A
Authority: GB
Inventors: Wolfgang Reik; Johann Jaeckel
Original assignee: LuK Lamellen und Kupplungsbau GmbH
Current assignee: LuK Lamellen und Kupplungsbau GmbH
Priority date: 1993-06-19
Filing date: 1994-06-17
Publication date: 1998-09-23
Anticipated expiration: 2014-06-17
Also published as: GB2323425B; GB9814352D0

Abstract

Two flywheel masses 303,313 are rotatable, both together and relative to each other, about a common axis. Dampers with coil springs 310 oppose rotation of the flywheels relative to each other. One flywheel mass 313 is connectable with the output shaft of an engine and the other (secondary) flywheel mass 303 can be coupled and uncoupled through a clutch with a gearbox input shaft. The primary flywheel mass has a radially extending flange-like area for connection to the output shaft of an engine through screws provided radially inwardly of the energy accumulators. The primary flywheel mass has radially outwards a mass ring fitted on and/or moulded on in one piece. The secondary flywheel mass 303 has an annular friction face 382 for a clutch disc and a friction device 354 is mounted radially outside of the damper 310,311.

Description

Flywheel Device The invention relates to a flywheel device with at least two flywheel masses rotatable relative to each other by means of a bearing against the effect of a damping device with peripherally-acting energy-storage mechanisms acting in a direction, where one flywheel mass - the first - can be connected to the output shaft of a combustion engine and a further - second - with the drive shaft of a gearbox via a friction clutch.

It is an object of the present invention to create a flywheel device characterised by a compact design both axially and radially. Furthermore, it was intended to open up the possibility of implementing as large an effective friction diameter of the friction clutch as possible for a given available construction space or of keeping the dimensions of the overall unit as compact as possible for a specified friction diameter. A further object of the invention is to extend the lifetime of such flywheel devices and therefore to enable their reliable use in, for example, motor vehicles.

A further object of the invention is to be able to attach the flywheel device as a unit to the combustion engine's output shaft as simply as possible. Moreover, inexpensive and economic manufacture and assembly of such flywheel devices should be possible.

Furthermore, the invention had the object of reducing the number of individual components and also protecting natural resources by minimum use of materials and minimum material waste, while at the same time, as a result of a reduction in production processes, protecting the environment both through energy savings and also through a reduction in processing additives used hitherto.

A further object underlying the invention is to protect the components of the flywheel device against excessive torques acting on them and thereby to prevent transmission of these excessive torques to the gearbox positioned downline of the flywheel device.

According to the invention, there is provided a flywheel device, more particularly for motor vehicles, with at least a primary and a secondary flywheel mass which are mounted coaxially relative to each other wherein the primary flywheel mass is connectable with the output shaft of an engine and the secondary flywheel mass can be coupled and uncoupled through a clutch with a gearbox input shaft, a damper with an input part and an output part is mounted between the two flywheel masses with the input part being connected to one of the flywheel masses and the output part being connected to the other of the flywheel masses and the input and output parts having sockets for energy accumulators which are mounted between the input and output parts and counteract relative rotation of the two flywheel masses, furthermore the two flywheel masses can be mounted as a unit on the output shaft of an engine wherein for this the primary flywheel mass has a radially extending flangelike area for connection to the output shaft of the engine through screw means provided or to be provided radially inside the energy accumulators, the primary flywheel mass has radially outwards a mass ring fitted on and/or moulded on in one piece, furthermore the secondary flywheel mass has a ring-shaped friction face for a clutch disc and a friction device is mounted radially outside of the energy accumulator.

For a flywheel device in accordance with the invention it can be advantageous if, for example depending on requirements, the flywheel masses are mounted coaxially relative to each other through a bearing and if the bearing is implemented as a plain bearing or, in other cases, a roller bearing.

It can be advantageous for the energy accumulators to be formed by the use of helical springs, though the use of leg springs can also be expedient.

In general it can be advantageous for the bearing to be located radially inside the energy-storing mechanisms.

An advantageous embodiment of a flywheel device in accordance with the invention can provide for a situation where the cover plate which forms the second chamber wall is permanently attached radially outside the energy-saving mechanisms to the cover plate forming the first chamber wall, for example by means of a welded joint or bead, though it can in turn be expedient to seal the joint by using an O- ring between the chamber walls.

It is possible for the cover plates forming the chamber walls to have load-application areas for the energy accumulators, where it may be expedient for the loadapplication areas to be formed by facing axial indentations which project axially into interspaces between the energy accumulators.

It can be particularly advantageous in a flywheel device according to the invention for the cover plates to be connected to the second flywheel mass where it can prove expedient for the cover plates to be joined to the side of the second flywheel mass facing away from the friction surface, i.e. to engage the counter-pressure plate.

The cover plates can be connected positively or by friction to the second flywheel mass.

In general it can be particularly advantageous in a flywheel device for a torque-limiting mechanism or a slip clutch to be provided in the power transmission train such that the torque flow - seen from the engine - proceeds from the first flywheel mass via a flange section projecting into the chamber and acting on the energy-storage mechanisms, to the energy-storage mechanisms, from there to the chamber walls, from there to the friction surface of the torque-limiting device, which surface is radially outside the energy-storage mechanisms but is radially inside the friction area of the friction clutch that lies further out in a radial direction or which protrudes only negligibly into said friction area, and from there to the second flywheel mass.

It can be further advantageous for the friction connection to be axially pre-stressed, with a cup spring exerting the required axial force for the axial pre-stress.

It can be expedient for the axial force to be variable by actuating the cup spring, and it can be advantageous for the cup spring to be actuated by the first flywheel mass. The actuator for this can be implemented as an integral part of the first flywheel mass.

It can prove advantageous for the cover plates of a flywheel device in accordance with the invention to be connected to the second flywheel mass with an intermediate layer of friction material, where said friction material can also form a thermal insulation layer.

It can be advantageous furthermore if a cover plate forming a chamber wall is borne by the bearing or can be supported by the bearing.

It can be particularly advantageous for a flywheel device in accordance with the invention if the energy-storage mechanisms are supported at the other end on loadapplication areas which are located on a flange or flanges connected to the first flywheel mass radially inside the energy-storage mechanisms, and it can be expedient for the connection of the flange(s) to the first flywheel mass to be made using fastening screws which serve to connect the first flywheel mass or the flywheel device to the output shaft of the combustion engine.

An expedient embodiment of a flywheel device in accordance with the invention can provide for two flanges which are permanently attached to each other in the region of their outer diameter.

It can furthermore be advantageous for the two flanges to lie flush against each other in the region of the screws which serve to connect the device to the crankshaft.

It can also prove expedient for the two flanges to be distanced from each other axially in the radial area between the fastening screws and their outer diameter.

In general it can be particularly advantageous for flywheel devices for the load-application areas of the flanges connected to the first flywheel mass or of the flange connected to this to be matched to energy-storage mechanisms formed by helical springs whose end coils are essentially the same as their intermediate coils. The spring ends are thus neither laid flush nor partially ground but simply cut or "chopped off".

It can furthermore be expedient for the load-application areas of the flange or flanges to be stepped for integrallymounted inner and outer springs.

It can also be advantageous for the cover plates to have stepped load-application areas for integrally-mounted inner and outer springs, with said load-application areas being expediently formed by a double indentation.

For a flywheel device in accordance with the invention it can prove advantageous for the first flywheel mass and a flange to be centred relative to each other directly via a seat.

It can also be advantageous for one flange to have a centring seat to centre the flywheel device on the output shaft of the combustion engine. For the construction of a flywheel device in accordance with the invention, for example, it can be expedient for the flange to bear the bearing assembly.

It can be particularly advantageous for a flywheel device in accordance with the invention to have two flanges for applying a load to the energy-storage mechanisms, one of which serves to attach the flywheel device to the combustion engine's output shaft, centre it on the output shaft, accommodate the bearing and centre the first flywheel mass.

An advantageous embodiment of a flywheel device in accordance with the invention can be to have a radially inner chamber seal formed in each case by a cup-spring-like component which acts on the one hand on a cover plate forming a chamber wall or on a component connected to the same and, on the other hand, on the flange adjacent to this or a component connected to the same.

It can be expedient, for example for a flywheel device manufactured as a pre-assembled module, if a component connected to a flange serves to hold the fastening screws, where said components acts on the cup-spring-like seal.

In this regard it can be advantageous for a cover plate to show cutouts to allow passage of the fastening screws or of a tool to operate the fastening screws, and it can in turn be expedient for the cutouts to be surrounded by a collar which can act on one of the cup-spring-like seals.

The cup-spring-like seals can furthermore represent a friction-damping device which can be inexpensive to implement.

An advantageous embodiment of a flywheel device in accordance with the invention can be characterised therein that the energy-storage mechanisms or the chamber and the friction clutch's friction surface located on the second flywheel mass are configured in the same axial area, i.e.

overlap each other axially.

Furthermore it can be advantageous for the compactness of the overall unit for the bearing and the heads of the fastening screws to be configured in the same axial area.

It can be particularly advantageous for a flywheel device in accordance with the invention for the energy-storage mechanisms (or chamber) to be configured radially between the heads of the fastening screws and the friction clutch's friction surface located on the second flywheel mass.

It can be expedient in a flywheel device in accordance with the invention to provide for a wall on the side of the chamber facing the heads of the fastening screws.

In very general terms a particularly advantageous embodiment of a flywheel device can be characterised by the radial sequence of at least four of the following seven components: - profile section of the gear shaft - bearing - heads of the fastening screws - radially inner chamber wall - energy-storage mechanism - radially outer chamber wall - friction surface of the second flywheel mass where the components can be located on various diameter areas which do not overlap.

Furthermore it can be expedient for the (at least four) components to be located in the same axial area.

For a flywheel device in accordance with the invention it can prove particularly advantageous for the bearing to be located radially inside the fastening screw heads.

A configuration of the fastening screw heads between the bearing and the energy-storage mechanisms can be just as advantageous as a flywheel device design in which the energy-storage mechanisms and the fastening screw heads are adjacent and located in the same axial area.

In addition, it can be expedient for a wall forming or partially forming the chamber to be located radially between the energy-storage mechanisms and the fastening screw heads.

For many applications, furthermore, it can be advantageous for the bearing to be located radially outside the fastening screw heads.

For a flywheel device in accordance with the invention it can be particularly advantageous for the energy-storage mechanisms of the damping device to have a length/diameter ratio in the range of 4 to 10, i.e. to have a large length/diameter ratio.

It can also be advantageous for the energy-storage mechanisms to extend over an area of between 70% and 95% of the periphery, and preferably between approx. 80t and 90%.

It can prove expedient for at least one energy-storage mechanism to extend over a sector of the periphery of greater than 140 .

In a flywheel device in accordance with the invention it can be particularly advantageous for the energy-storage mechanisms to be bent forward at least approximately to the radius which corresponds to the fitted state.

Various embodiments of a flywheel device in accordance with the invention can show a plurality of spring steps.

With flywheel devices in accordance with the invention in general it can prove particularly advantageous for energystorage mechanisms in the form of helical springs to have end coils which correspond essentially to their intermediate coils, i.e. are neither partially ground nor laid flush but are merely cut or "chopped off" in the region of a plane which is approximately perpendicular to the wire crosssection.

A flywheel device in accordance with the invention can expediently be provided with an anti-wear device between the energy-storage mechanisms and the radially outer chamber wall against which the energy-storage mechanisms support themselves, at least by centrifugal force.

It can prove expedient with a flywheel device in accordance with the invention for the case of the friction clutch to be centred on the second flywheel mass.

It can furthermore be advantageous for the friction clutch case axially to enclose the second flywheel mass, whereby the radially-running area of the friction clutch case which encloses the second flywheel mass can be centred on said second flywheel mass.

For a flywheel device in accordance with the invention it can be expedient for the cover to be connected to the second flywheel mass by means of a welded, i.e. permanent or inseparable, joint.

For other embodiments, however, it can be expedient for the cover to be connected to the second flywheel mass such that they can be separated, for example by means of screws or pins.

It can also prove expedient to implement a flywheel device such that the cover itself can be separated, for example in similar fashion to that described in German patent application P 42 32 320 in order, for example, to be able to replace the clutch plate.

In a flywheel device in accordance with the present invention it can be advantageous for the clutch plate carrier plate of the friction clutch to be matched at least in essence to the contour of the chamber.

Such flywheel devices can advantageously have a lubricantdiverting plate and/or a lubricant-diverting contour on the carrier plate of the clutch plate and/or on the cover plate facing it and forming a chamber wall, in the region of the cutouts made in the cover plate.

It can prove expedient for the clutch plate carrier plate to show cutouts to allow passage of the fastening screws or of a tool to operate the fastening screws.

In the case of a flywheel device in which the friction clutch pressure plate can have a load applied to it by a cup spring with an annular base and lugs it can be advantageous for the contour of the cup spring to be at least approximately matched to that of the clutch plate carrier plate, at least in the position in which the cup spring and the carrier plate are in close proximity, and it can be expedient for the cup spring to show cutouts in the region of its lugs to allow passage of the fastening screws or passage of a tool to operate the fastening screws.

In general it can be particularly advantageous in flywheel devices for the cup spring to show cutouts to allow passage of pressure plate cams located on the friction clutch pressure plate where a simple method of providing the cutouts can be the at least partial omission of lugs.

In flywheel devices very generally it can be particularly advantageous for the leaf springs which connect the pressure plate to the friction clutch case such that it cannot rotate though is axially displaceable to be located on the side of the cover facing away from the pressure plate.

Furthermore, it can be expedient, with regard for example to the axial construction space, for the side of the pressure plate opposed to the friction surface to be matched to the contour of the cup spring bearing on the cover side, i.e.

has an indentation into which the cup spring bearing elements (wire ring(s) and its/their retaining elements) project axially at least partially when the pressure plate is disengaged.

By the same token it can be advantageous for the pressure plate and the components of the cup spring bearing on the cover side to overlap axially and radially when the friction clutch is disengaged such that the cup spring bearing can project into corresponding indentations in the pressure plate.

An advantageous embodiment of a flywheel device in accordance with the invention can be implemented such that the cup spring bearing on the cover side being formed by fishplates which are integral parts of the cover where the side of said pressure plate opposed to the friction surface is matched to the contour of the fishplates.

Furthermore, it can be particularly advantageous for the first flywheel mass to be at least partially matched to the contour of the areas of the chamber facing it.

It can be of benefit, for example in respect of cost, for the first flywheel mass to be manufactured mainly from sheet-metal (components) It can also prove expedient for the first flywheel mass to bear the starter motor gear.

The starter motor gear can advantageously be formed by a folded sheet-metal component whose walls lie flush against each other as described, for example, in German patent application P 43 15 209.

It can also be expedient to implement the starter motor gear as an integral part of the first flywheel mass.

To increase the primary-side moment of inertia it can be advantageous for the flywheel device's first flywheel mass to show a mass ring, where said mass ring can be formed by a casting or a folded sheet-metal part.

With a flywheel device in accordance with the invention it can be particularly advantageous for the mass ring to enclose the axial area of the clutch case and overlap this at least in part in an axial direction.

It can prove advantageous for the flywheel device's damping device to show a load friction device where the latter can advantageously be located radially outside the energystorage mechanisms or radially outside the average frictional diameter of the friction clutch.

In general with flywheel devices it can be advantageous for the load friction device to contain at least one friction part with two radially-spaced friction surfaces.

Furthermore, the friction part can show the friction connection with the first flywheel mass.

It can be expedient for the friction part to be capable of having a load applied to it by a load-application part of the second flywheel mass.

With such friction devices it can be advantageous for the friction parts and load-application parts to have a certain play peripherally.

In this regard a plurality of friction parts can be provided with varying play relative to the load-application parts.

An expedient flywheel device design can provide for an axial part of the friction clutch case to be part of the load friction device.

It can furthermore be advantageous to use the mass ring of the first flywheel mass as an integral part of the load friction device.

The load friction device can advantageously be located in the area in which the mass ring encloses the axial area of the clutch case.

It can be advantageous, for example for the function of the hysteresis device, for the load friction device to show at least one energy-storage mechanism, where said energystorage mechanism can act in a radial direction.

It can prove advantageous in a flywheel device in accordance with the invention for the load friction device to be formed by at least one friction shoe located in the first flywheel mass, where it can be expedient for the friction shoe to be merely clipped into place.

In this regard it can be advantageous for the load friction device to show a plurality of friction shoes distributed over the periphery.

For defined frictional properties, for example, it can be advantageous for at least the friction surface(s) of the friction shoe(s) to be made of plastics, such as PTFE, PEEK, PA6.6.

It can be particularly advantageous in respect of the durability of a flywheel device in accordance with the invention for the clutch plate carrier plate and/or the cup spring to show further cutouts, particularly to ventilate the flywheel device.

Furthermore, it can be expedient in this regard for ventilation apertures to be provided in the axial or radial areas of the friction clutch case.

It can also be advantageous to provide ventilation apertures in the first flywheel mass or also in the second flywheel mass, in this case radially outside the chamber.

A flywheel device in accordance with the invention can advantageously be characterised by ventilation by means of an air current through the carrier plate of the clutch plate, along the chamber wall, through apertures in the second flywheel mass outside the chamber towards the first flywheel mass.

To improve temperature conditions further, a flywheel device in accordance with the invention can have ventilation apertures in the first flywheel mass for an air current which is directed at the chamber wall and flows past the second flywheel mass.

It can furthermore be advantageous to provide ventilation apertures in the first flywheel mass for an air current directed at the second flywheel mass.

An advantageous embodiment of a flywheel device can have surface projections to improve heat dissipation on the side of the second flywheel mass facing away from the friction surface or on the side of the pressure plate facing away from the friction surface, where said projections can be formed by pressings or hobbing with an annular milling machine or similar.

It can be expedient for the surface projections and/or ventilation apertures to be implemented in the form of impellers.

A preferred embodiment of a flywheel device in accordance with the invention can be implemented such that the flywheel device together with the friction clutch and clutch plate forms a unit which can be pre-assembled and can be screwed as such with the fastening screws to the combustion engine's output shaft from the side facing away from the engine, where said fastening screws (captive, if appropriate) can be contained in the unit.

A flywheel device in accordance with the invention can advantageously be implemented both with a friction clutch as a so-called compressed clutch and with such a clutch as a so-called tension clutch.

In general it can be advantageous for flywheel devices to be configured such that the second flywheel mass, torquelimiting device/slip clutch and the peripherally-acting energy-storage mechanisms are radially aligned, and where the energy-storage mechanisms can be located in an essentially closed chamber which extends in a peripheral direction.

An expedient embodiment of a flywheel device in accordance with the invention can be characterised by the radiallyaligned configuration of the bearing.

An advantageous form of a flywheel device can be implemented such that the torque-limiting device/slip clutch is located radially between the energy-storage mechanisms and the second flywheel mass.

The invention is described in greater detail with reference to the Figures in which: Figure 1 shows a cross-section through a flywheel device in accordance with the invention Figure 2 shows a partial view of a flywheel device in accordance with the invention in the direction of arrow II in Figure 1 Figure 3 shows a view of a possible spring configuration Figure 4 shows the configuration of a friction device in partial cross-section Figure 5 shows a friction shoe in a different embodiment for the friction device according to Figure 4.

Figures 6 to 8 show cross-sections or partial cross sect ions of further flywheel devices in accordance with the invention Figure 9 shows a simplified partial view in the direction of arrow IX in Figure 8 Figure 10 shows a partial cross-section of a further flywheel device in accordance with the invention Figure 11 shows a partial cross-section in accordance with arrow XI in Figure 10 Figure 12 shows a partial cross-section in accordance with arrow XII in Figure 10 Figures 13 and 14 show partial cross-sections of further flywheel devices in accordance with the invention Figure 1 shows a split flywheel 1 which consists of a first or primary flywheel mass 2, which can be attached to a crankshaft (not shown) of a combustion engine, and of a second or secondary flywheel mass 3. To this second flywheel mass 3 is attached a friction clutch 4 with an intermediate clutch plate 5, by means of which a gearbox (also not shown) can be engaged and disengaged. This clutch plate 5 is shown here as a rigid item, though this stands only as an example. This clutch plate 5 can, for example, also be implemented in different embodiments which contain friction and/or damping elements or can also be fitted with a resilient cover.

In this case the flywheel masses 2 and 3 with permanently attached components placed between them are mounted by means of a bearing 6 such that they can rotate relative to each other, where said bearing 6 in this example is located radially inside the bores 7 which allow passage of the fastening screws 8 to mount the first flywheel mass 2 or the entire flywheel device 1 on the output shaft of a combustion engine. The single-row ball bearing 6 illustrated here has a sealing cap 6a with a lubricant reservoir, where said sealing cap 6a serves at the same time as a thermal insulation material by reducing the heat flow from the second flywheel mass 3 to the bearing 6 or prevents a thermal bridge. A damping device 9 acts between the two flywheel masses 2 and 3, where said damping device 9 in this case shows helical compressive springs 10 which are located in an annular space 11 that forms an approximately torusshaped area. The helical compressive springs 10 used and shown here can also be replaced by suitable energy-storage mechanisms of a different design such as leg springs. The annular space 11 is at least partially filled with a dryfilm lubricant such as graphite powder or similar or with a paste-like, viscous medium such as oil or grease.

The primary flywheel mass 2 contains a component 13 which can in the preferred embodiment be made of sheet metal or drawn where said component 13 serves to attach the first flywheel mass 2 or the entire split flywheel 1 to the output shaft of a combustion engine or a shaft connected to the same. The component 13 forms a flange-like area 14 running essentially radially which bears a flange 15 radially inside, whose radially-running areas 15a with the cutouts 7 has aligned bores or apertures for the fastening screws 8.

The inner ring 16 of the single-row roller bearing 6 is accommodated on the outer sleeve surface or shoulder in the axial end section 15b of the flange 15. The second flywheel mass 3 contacts the outer ring 17 of the roller bearing of the bearing assembly 6.

The area 14 which runs essentially radially merges in its radially outer region into an area 18 which bulges axially towards the combustion engine, where said area 18 in turn merges radially outwards into a radially-extending area that is further axially than the latter from the combustion engine and forms the starter motor gear 19. To form the starter motor gear 19 the material of the sheet-metal component 13 is deformed and folded in its radially outer area such that a radially inward-facing leg 20 is formed whose wall in turn lies flush against the radially outer section of the sheet-metal component 13. The profiles or the gearing of the starter motor gear 19 can be produced in this sheet-metal part after folding of the sheet metal.

These profiles can be produced by machining, e.g. milling or broaching. The profiles in the starter motor gear 19 can also be formed, however, by pressing, i.e. a flow process in the material. These profiles can also be formed by stamping. A further possible means of production of such profiles is to cut them out using high-energy radiation, such as laser beams. It can be advantageous for the relevant sheet-m shorter than the radially inner leg 23 and its radiallyextending end section 22a lies flush against the axiallyextending leg 20 of the starter motor gear 19. If the mass ring 21 is manufactured thus, its contours can, for example, be matched to the inner cover contours of the housing which accommodates the twin-mass flywheel, such as the gearbox case, as a result of which no contact can take place. To this end a tapered bevel 22b is moulded onto the mass ring 21 in this example. The material displaced in producing the bevel 22b was used to increase the thickness of the radially outer leg 22.

The radially inner leg 23 faces towards the combustion engine and merges into the radially-running leg 25 of the mass ring 21 in the axial area of the starter motor gear 19, forming a bend or curve 23a. This bend 23a and the radially-running leg 25 of the mass ring 21 lie flush against the side facing away from the combustion engine of the bulge 18 of the first flywheel mass 2. Radially inside this area of contact the leg 25 has a section 25a offset axially towards the secondary flywheel mass 3, where the wall of said section 25a lies flush against the wall of the second radially-extending leg 24. The leg 24 extends beyond the section 25a radially outwards and finishes at a radial spacing from the axially-running leg 23. In the region of the bend 23a, the mass ring 21 is permanently connected to the primary flywheel mass 2 by a plurality of welded points 27 distributed about the periphery and located in cutouts 26.

The flange 15 is connected to and centred on the first flywheel mass 2. Centring can be carried out, for example, by means of a centring seat 28 which acts on a corresponding cutout in the sheet-metal component 13. It is also possible for centring and, if appropriate, fixation of the flange 15 on the first flywheel mass 2 to be achieved by means of individual buttons 29 which in the example illustrated here protrude from the side facing away from the combustion engine using material from the flange 15. Furthermore the flange 15 has a centring seat 30 on its radially inner side which serves to centre the twin-mass flywheel 1, for example on an engine crankshaft.

Radially outside its radially-running area 15a, the flange 15 extends diagonally initially in a radially outwards direction away from the combustion engine before then extending radially again in its radially outer area. In this radially outer area the flange 15 is permanently connected to a second flange 31. Here too the permanent connection is formed by using material from the flange 15 to form connecting buttons 32. Radially inside these connecting buttons 32 the flange 31 extends essentially radially inwards, showing a slight bulge 33 away from the combustion engine side. Radially inside the bulge 33, the flange 31 merges into an area 31a extending axially towards the combustion engine, where said area 31a in turn merges into an area 31b extending radially inwards. The radial area 31b lies flush against the radial section 15a of the flange 15 and, like the latter, has cutouts to allow passage of the fastening screws 8 where the side of the radial area 31b facing away from the combustion engine side can form an engaging surface for the heads of the fastening screws 8.

In their radially outer area or in the area of the bulge 33, the flanges 15 and 31 form load-application areas 34 and 35 for the energy-storage mechanisms in the form of helical springs 10. As can be seen in particular by reference to Figure 3, the load-application areas 34 and 35 are formed by radially-running extensions 15c and 31c which project into interspaces between the peripherally-acting energy-storage mechanisms 10. Furthermore, Figure 3 reveals in particular that the point of action, i.e. the beginning of the application of load to the energy-storage mechanisms 10 can be made either the same or different, i.e. stepped, for the inner and outer springs. It can also be seen that the extensions 31c and 15c do not overlap axially, i.e. do not match each other. Rather, the extensions 15c,31c and their load-application areas 34,35 are formed such that they are matched to the relevant spring ends of the energy-storage mechanisms 10 acting on them.

In the example illustrated, the spring ends acting on the load-application areas 34 and 35 have only one separation point and are neither laid flush with the preceding coil nor partially ground in their terminal area perpendicular to the spring's centre line. This means that the terminal coils of the energy-storage mechanisms 10 correspond in essence to every other coil within the energy-storage mechanism 10, i.e. have practically the same pitch by analogy with a screw for example. This makes it possible to use these terminal coils as springing coils, rendering non-springing coils superfluous, as a result of which more spring power or a shorter spring length can be achieved. Furthermore with such an implementation of the spring ends it is advantageous that the spring material merely has to be cut, meaning that the procedures otherwise required, such as laying the last spring coil flush against the one preceding it, and the partial grinding of the spring end to achieve a smooth flush end, are superfluous.

Such a spring design in connection with appropriately matched load-application areas is not restricted to the cited example of a twin-mass flywheel but can be used in every other configuration, e.g. with dampers. Furthermore it is possible to replace the two flanges 15 and 31 by a component, e.g. a sintered or forged component, with which here too the load-application areas 34 and 35 for the energy-storage mechanisms 10 can be appropriately matched.

The energy-storage mechanisms 10 support themselves at the other end with the inner spring on load-application areas 36a and 37a and with the outer spring on load-application areas 36b and 37b. The load-application areas 37a,b and 36a,b can be configured at the same level or offset, viewed peripherally. This in turn enables a clear specification of the beginning of load application to the energy-storage mechanisms. The energy-storage mechanism load-application areas 36a,b are located on a first cover plate 38 which is supported radially inwards on the bearing unit 6 or on the outer ring 17 of the single-row roller bearing 6 and which bears the secondary flywheel mass 3 on its radially outer side.

To this end the cover plate 38 has a shoulder 39 in its radially inner area extending axially towards the engine, where said shoulder 39 has an inner diameter which is suitable for accommodating the outer bearing ring 17 with the sealing cap 6a. On its side opposed to the combustion engine, this shoulder has a diameter constriction 40 which serves as an axial stop or axial fixing point between the cover plate 38 and roller bearing 6. Starting from this cross-sectional constriction 40, the cover plate 38 runs from the combustion engine diagonally radially outwards, though this section 41 runs essentially in a straight line.

The straight section 41 contains cutouts 42 which are suitable for accommodating the heads of the fastening screws 8 and thus holding the fastening screws 8 in an essentially coaxial position relative to the rotational axis of the twin-mass flywheel 1 if the flywheel device 1 is not mounted or installed. The straight cover plate section 41 merges radially outwards into an area 43 of segment-shaped crosssection which is matched at least in essence to the outline of the energy-storage mechanisms 10 and at least partially encloses the latter axially and radially. A radial section 44 facing radially outwards is connected to the free end, facing the combustion engine, of the area 43, where said section 44 is permanently connected to a radial section 45 of the second cover plate 46 which is located axially between the cover plate 38 and the sheet-metal component 13.

The connection between the two cover plates 38 and 46 is sealed radially outwards by means of an O-ring 47.

The cover plate 46 partially encloses the O-ring 47 radially inside the radial section 45, and an area of said cover plate 46 extending axially away from the combustion engine side partially projects axially into the space enclosed by the cover plate 38. This ensures that the annular chamber 11 or the space 12 is sealed, and at the same time the cover plates 38 and 46 are centred relative to each other. From there the cover plate 46 runs in essence radially inwards, being in essence matched to the outline of the energystorage mechanism 10, and extends into the axial space between the sheet-metal component 13 of the first flywheel mass 2 and the flange 15.

Radially inside the load-application areas 37a and 37b the cover plate 46 has an area 48 which is axially stepped in the direction of the combustion engine and against which a cup spring 49 lies flush that is in radially inner contact with the flange 15, thereby forming a radially inner seal for the chamber 11. In this regard the cup spring 49 can be centred both in the region of the cover plate 46 and on the flange 15. A further cup spring 50 serves to seal the chamber 11 radially inwards between the flange 31 and the cover plate 38. To this end the outer diameter of the cup spring 50 lies flush against the bulge 33 of the flange 31, while its inner diameter is flush against the cover plate 38 in the region of the axially-running section 31a of the flange 31. To centre the cup spring 50, the cover plate 38 has a plurality of centring projections 51 distributed over the periphery which are formed by partial bending of the material of the flange 38. Instead of a plurality of centring projections 51 distributed over the periphery it is also possible to provide an annular closed projection or, on the other hand, to centre the cup spring 50 in appropriate fashion on the flange 31.

The radial areas 44 and 45 of the cover plates 38 and 46 bear the second flywheel mass 3 in the area of their outer diameter. In this regard the radial areas 44 and 45 are located on the side of the secondary flywheel mass 3 facing away from the friction surface, with the result that, in the event of any leakage or the failure of the O-ring 47, the medium or lubricant contained in the chamber 11 will be routed towards the primary flywheel mass 2 and thus will not be able to impair the friction effect on the friction surfaces of the clutch plate 5, meaning that the friction clutch 4 can continue to transmit the full torque. The connection to the second flywheel mass 3 in this example is made by means of a flanged steel plate 52, a connecting section 53 of which extends radially outwards, lies flush against the friction surface side of the secondary flywheel mass 3, largely overlaps the latter radially inwards and passes axially through cutouts in the radial areas 44 and 45. Furthermore, the flanged steel plate 52 includes lugs 54 on the combustion engine side which also point radially outwards when installed, thereby holding the two cover plates 38 and 46 against the flywheel mass 3. In their original state these lugs 54 extend in an axial direction towards the combustion engine and, after positioning and fitting of the secondary cover plate 38, the flanged steel plate 52 and the cover plates 38 and 45 are plastically deformed such that they point radially outwards as shown in Figure 1.

Together with the clutch unit, comprising the clutch 4 and the clutch plate 5, the twin-mass flywheel 1 forms a module which is pre-assembled as such and can be despatched, stored and fitted in a particularly straightforward and efficient manner to the crankshaft of a combustion engine since this design renders a number of procedures superfluous such as the otherwise necessary centring procedure for the clutch plate, the procedure for fitting the clutch plate, mounting the clutch, introducing the centring pin, centring the clutch plate itself and, if necessary, inserting the screws, screwing the clutch down and removing the centring pin.

The fastening screws 8 can already be pre-mounted or contained in the bores of the flange section 14 and the flange 15; it is expedient for them to be held in a captive position, for example by means of flexible devices which are sized such that their retaining force is overcome when the screws 8 are tightened.

The clutch plate 5 is mounted in a pre-centred position relative to the unit's rotational axis between the pressure plate 55 and the friction surface of the secondary flywheel mass 3 and moreover in such a position that the apertures 56 provided in the clutch plate 5 are configured such that a screwing tool can pass through when fastening the unit to the output shaft of a combustion engine. Furthermore, as shown in the embodiment illustrated, the apertures 56 can be smaller than the heads of the screws 8 which also ensures that the screws 8 are properly held captive within the unit.

The cup spring 57 also incorporates cutouts or apertures in the region of its lugs 57a to allow passage of a screwing tool, though these are not shown in detail in this drawing.

These cutouts can form expansions of the slits which are present between the lugs 57a. The apertures in the cup spring 57 and the apertures 56 in the clutch plate 5 coincide axially, and therefore as a result of their axially aligned configuration allow the passage of a fitting tool to tighten the screws 8 and thus attach the unit to the crankshaft of a combustion engine.

The friction clutch 4 which can be actuated by the cup spring 57 has a hinged device 58 on the one hand on the side towards the clutch case 60 and a hinged device 59 on the side opposed to the clutch case 60. The hinged devices 58 and 59 formed by wire rings are retained by fishplates 61 distributed about the periphery. The fishplates 61 are constructed as integral elements of the clutch case 60 and formed by appropriate deformation of the material of the same. The fishplates 61 at least partially enclose the hinged device 59 on the side opposed to the clutch case 60 in an axial and radial direction. Fixation of the hinged device 58 is ensured radially outside the hinged device 58 by means of a bead 62 embossed in the clutch case 60.

Instead of a continuous closed bead 62, a plurality of partial beads can be distributed about the periphery. As can be seen in the drawing, the pressure plate 55 is matched, at least in the area of the fishplates 61, to their contours and in the other areas to the contour of the hinged device 59. It can, however, also be expedient to leave it constantly matched to the fishplates 61 over the entire periphery, in contrast to the example shown.

Leaf spring elements 63 which - as can be seen with reference to Figure 2 - are connected on one side via a rivet 64 to the housing or case 60 and on the other side via a rivet 65 to the pressure plate 55 for torque transmission purposes and to raise the pressure plate 55. The riveted connection to the pressure plate 55 is made in the area of the pressure plate cams 66 which in this example project radially inwards and are located radially inside the friction linings of the clutch plate 5. The pressure plate cams 66 pass through the cup spring 57 axially in the region of cutouts 67 such that the leaf spring elements 63 are located on the side of the case 60 facing away from the pressure plate 55. Such a leaf spring configuration is not restricted to use with a split flywheel but can also be used very generally with differently designed clutch types and also in conjunction with, for example, a conventional flywheel. As can be seen in particular with reference to Figure 2, the required cutouts 67 can be formed by means of the omission of parts of the cup spring lugs 57a or even omission of complete cup spring lugs 57a. The cup spring lugs 57a are matched to the contour of the carrier plate of the clutch plate 5 and with the compressed clutch type shown here run approximately parallel to the friction clutch 4 when the latter is disengaged.

In addition to the cutouts 42 in the cover plates 38 and 56 in the clutch plate 5, other apertures 68 and 69 are provided in the region of the clutch case 60,5a in the clutch plate 5,70 in the secondary flywheel mass 3 and 71 in the sheet-metal component 13 of the primary flywheel mass 2 to cool the entire unit. One of the purposes of adequate cooling of the entire unit is to prevent the paste-like medium such as grease contained in the torus-shaped area 12 from becoming so hot that its viscosity is reduced such that it becomes liquid. Furthermore, an increased thermal load adversely affects on the unit's overall lifetime. For the purposes of further improving heat dissipation, surface projections can be provided in the secondary flywheel mass 3 (at 72) and/or in the pressure plate 55, where said projections like the apertures described above can be shaped like impellers.

The clutch case 60 which is permanently attached to the secondary flywheel mass 3 comprises in essence the axial area 73, that is essentially in the form of a hollow cylinder, and the at least essentially radially-running section 74 in the area of which the cup spring 57 is hingemounted. The axial area 73 axially encloses the secondary flywheel mass 3 and can be permanently attached to the latter axially and also in the direction of rotation by means of pin connections or also by means of a welded joint.

Further types of connection options are shown, for example, in German published application DE-OS 41 17 584.

Parts of the axial area 73 or axial lugs 75 extend axially beyond the secondary flywheel mass 3 towards the combustion engine. In their terminal axial area these lugs 75 project into the axial area which is limited radially inwards by the radial area 24 and radially outwards by the axial area 23 of the inertia body 21 or mass ring. A friction device 76 which can be actuated by the axial lugs 75 is located in this space enclosed by the mass ring 21. The friction device 76 contains at least one friction shoe 77 as shown, for example, in Figure 5. The friction shoe 77 comprises a plastic part 78, which is in essence matched to the available space or radius, and one or more energy-storage mechanisms 79 which can spread the plastic part 78 radially.

The friction shoe 77 is fixed axially in that it has a catch device 80 on its radially inward side which acts on the mass ring 21. In the example illustrated here the catch device 80 consists of a conical surface where the tip of the cone points towards the combustion engine and engages a corresponding undercut, i.e. a recess which is also conical, in the radial area 24.

The friction shoe 177 shown in Figure 4 has a different design from that of friction shoe 77. In this case an initially flat plastic part 178 is radially pre-stressed in that the initially flat plastic part 178 is installed in a deformed manner in the curved space enclosed by the mass ring 21 together with a round wire 179 acting as a leaf spring. Figure 4 shows furthermore that the axial lugs 75 can also be positioned at a certain distance 81 from the friction shoe 77 or 177, which makes it possible for the friction effect to act only after a certain angle of rotation, once the play or distance 81 has been bridged. In the event of a plurality of friction shoes 77 or 177 distributed about the periphery it is furthermore possible to vary these distances such that a graduated friction effect is achieved. Thus friction shoes 77 or 177 can also be inserted without play between the relevant axial lugs 75.

It is also possible to graduate or affect the frictional force by using different materials for the friction shoes 77,177 or fitting these friction shoes 77 or 177 with varying radial pre-stress.

In Figure 6 components which are similar to or the same as the components described to date are assigned similar reference signs, though increased by 100.

The split flywheel 101 matches the fundamental design of the twin-mass flywheel 1 described above, though differs in having a plain bearing 106 instead of the roller bearing 6.

To form the plain bearing seat 106 a plain bearing material, in this case in the form of a plastic bush 106b, is applied to the outer sleeve surface or shoulder in the terminal axial section 115b of the flange 115. The bearing bush 106b extends from the free end of the terminal axial section 115b, against which it lies flush with its inward-facing collar 106c, initially towards the combustion engine and then forms a curve to merge into a radially outward-facing area 106d which lies flush against the support area 115d of the flange 115. The free end 139a on the combustion engine side of the shoulder 139 of the cover plate 138 whose inner periphery encloses the bearing sleeve 106b matches the outline of the bearing sleeve 106b or its radially outwardfacing section 106d, where said shoulder 139 initially extends axially towards the engine. Such a design ensures that the cover plate 138 and with this the secondary flywheel mass 103 with the attached clutch 104 can be supported both radially and also at least axially. In a deviation from the example illustrated here it is possible to provide the supports for the radial force and axial force components with separate bearing sleeve parts.

The connection of the carrier plate of the clutch plate 105 to its hub or hub flange is not riveted as in the example shown in Figure 1 but is a friction-welded joint 105b. It is also possible for this connection to be made using the hub flange material, as a result of which again no additional connecting components are required. These connections can thus be made economically with minimal parts input.

A further possible embodiment is shown in Figure 7 where similar reference signs are again used, though increased by a further 100, for the same or similar components.

The twin-mass flywheel 201 illustrated here differs from the embodiment according to Figure 1 in essence in the connection of the secondary flywheel mass 203 to the cover plate 246. The cover plate 246 has an extended radial area 245 which overlaps the secondary flywheel mass 203 radially and which merges at its radially outer end into an axial area 245a facing away from the combustion engine. With this axial area 245a the cover plate 246 axially overlaps the secondary flywheel mass 203 at least partially and together with the latter is permanently connected by means of pins to the axially-running area 273 of the clutch case 260. In the radially inner area of the secondary flywheel mass 203 the cover plate 246 is permanently attached to the cover plate 238 by means of lugs 246a which initially face axially away from the combustion engine, pass axially through the radial area 244 of the cover plate 238 and are plastically deformed after assembly of these parts such that they face radially inwards on the side of the secondary flywheel mass 203.

These lugs 246a are formed directly from the material of the cover plate 246, and a supplementary flanged steel plate, similar to the flanged steel plate 52 in Figure 1, is therefore superfluous. A further advantage of this design is that heat transfer from the secondary flywheel mass 203 to the two cover plates 238 and 246, and thus the direct effect on the lubricant, is reduced. Furthermore, additional cutouts 245b in the radial area 245 of the cover plate 246 serve particularly to cool the unit.

In this example, friction shoes 177 an embodiment of which is shown in Figure 4 and which engage the leg 224 of the mass ring 221 with a catch device 180 are provided for the friction device 276. With a friction shoe 177 implemented in this way the radially outer limit of the leg 224 can remain parallel to the axis, rendering procedures to produce the conical design according to Figure 1 superfluous and thereby making economic manufacture possible.

Figure 8 illustrates a further embodiment of a flywheel device in accordance with the invention where the reference signs for similar or the same components are again increased by a further one hundred.

By contrast with the twin-mass flywheel 1 shown in Figure 1, the split flywheel 301 incorporates a mass ring 321 of approximately S-shaped cross-section which again accommodates a friction device 376. In essence, the friction device 376 corresponds in function, configuration and design to the friction devices described hitherto.

By contrast with the flywheel devices described hitherto, the twin-mass flywheel 301 shows a torque-limiting device or slip clutch 381 whose point of action is located between the secondary flywheel mass 303 and the cover plates 338 and 346 which form the chamber 311. The connection of the secondary flywheel mass 303 to the cover plates 338 and 346 is made by means of a flanged steel plate 352 in similar fashion to that described in connection with Figure 1. Friction material 382 in the form of a friction lining is applied between the secondary flywheel mass 303 and the flanged steel plate 353 or cover plate 338. At the same time this lining serves as thermal insulation material towards the chamber 311 containing the lubricant. A cup spring 383 is located between the radial area 345 of the cover plate 346 facing the sheet-metal component 313 and the deformed retaining lugs 354 of the flanged steel plate 352, where said cup spring 383 generates an axial force which tensions the secondary flywheel mass 303, the flanged steel plate 352 and the radial areas 344 and 345 relative to each other such that as a result of the friction occurring at the friction lining 382 a certain torque or a certain peripherally-acting force can be transmitted by the slip clutch 381 and thus by the split flywheel 301.

The contact pressure of the cup spring 383 and thus the transmittable torque can be varied such that the transmittable torque in the area of the maximum relative rotation of the primary flywheel mass 302 to the secondary flywheel mass 303 is reduced, with the result that the primary and secondary sides can continue to rotate against each other with an at least partially disengaged slip clutch 381 in order in this way to prevent damaging excess torques from reaching further components or their transmission to the gearbox connected further downline. To this end the cup spring 383, as can be seen with particular reference to Figure 9, shows wings which are inclined out of their plane towards the combustion engine and can act on appropriately formed ramps 313a of the sheet-metal component 313.

In the event of relative rotation of the primary flywheel mass 302 and secondary flywheel mass 303 the lugs 383a and the ramps 313a approach and, after a certain angle of rotation, contact each other. If the relative rotation is continued in the same direction the lugs 383a slide up the ramps 313a and cause the cup spring 383 to approach the primary flywheel mass 302 axially, as a result of which the cup spring force is reduced. Such a reduction in the cup spring force causes at least partial opening of the slip clutch 381, as a result of which the secondary flywheel mass 303 with the attached clutch 304 can slip relative to the cover plates 338 and 346. In this regard the slip clutch 381 can act only in one direction of the relative motion or in both directions, and it can act in both directions of relative rotation equally, i.e. symmetrically, or variably.

The slip clutch or torque-limiting device 381 which is implemented here with end angle control is thus located on the secondary side and in a radial direction (aligned) between the secondary flywheel mass 303 and the energy storage mechanisms 310 in this embodiment as shown in Figure 8.

The construction shown in Figure 10 in turn is similar in essence to that shown in Figure 1, and similar reference signs, again increased by a further one hundred have been used for components performing the same or a similar function.

With the twin-mass flywheel 401 illustrated here, the flanges 415 and 431 are laid flush together for the entire extent of flange 431, i.e. there is no area in which there is any axial spacing between them. Furthermore, the sheetmetal component 415 of the primary flywheel mass 402 shows the centring seat 430 to centre the primary flywheel mass 402 or the entire twin-mass flywheel 401 on the output shaft of a combustion engine. The flanges 415 and 431 can also be provided in a single component which can be manufactured as a cast, forged or sintered part.

In this example the radially inner limit of the chamber 411 is formed by a separate component 484 forming a wall which in this case is manufactured of plastic and whose inner area additionally encloses the heads of the fastening screws 408 and can be suitably implemented to guide the latter and prevent tilting of the screws 408. In its radially outer area the plastic component 484 encloses the cup spring 450 which functions as a seal and acts at its other end on the cover plate 438. The cutouts 442 which serve to allow passage of a screwing tool or the fastening screws 408 are surrounded by an axial shoulder or collar 442a whose inner periphery is suitable for accommodating and supporting the fastening screws 408 if the twin-mass flywheel 401 is not yet fitted and for maintaining them in an at l axis of the flywheel device. In the radially outer area of their outer periphery these shoulders or collars 442a can form an auxiliary centring unit for example when fitting the cup spring seal 450.

In the example illustrated here, the secondary flywheel mass 403 is connected to the axial area 473 of the clutch case 460 by means of a plurality of mounting plates 485 distributed about the periphery. As can be seen with particular reference to Figure 11, the mounting plates 485 have radial projections which pass through appropriate cutouts in the axial area 473 of the clutch case 460. The mounting plates 485 are screwed using screws 485a to the side of the secondary flywheel mass 403 facing away from the friction surface, where said screws can be reached by means of apertures 485b in the first flywheel mass 402 which are also used for ventilation. In this regard varying radial and axial pre-stresses can be generated by varying the shapes of the contact areas between the mounting plates 485 and the secondary flywheel mass 403.

The sheet-metal component 413 of the primary flywheel mass 402 shows further ventilation apertures 471 and 471a where the radially inner apertures 471a are located approximately in the radial area of the chamber 411. This enables an air current to be generated which passes directly by the chamber 411, thereby preventing an inadmissibly high temperature increase in the lubricant contained in the chamber. Figure 10 illustrates moreover that the side of the sheet-metal component 413 facing away from the combustion engine is matched in the radial area of the chamber 411 at least in essence to its contour.

Figure 12 shows by way of example the configuration of the load-application areas 436a and 436b to which load application areas 437a and 437b are symmetrically implemented. In this regard the load-application areas 436a,436b,437a,437b are formed without any supplementary individual parts by axial deformation of the material of the cover plates 438 and 446 such that these deformations point axially towards each other. In order to achieve the peripheral graduation of the load-application areas 436a and 436b shown in Figure 12, these deformations can be formed by a so-called double indentation.

Although the twin-mass flywheel 401 illustrated does not have any separate friction device, it can be constructed both with a friction device for the idling range and also with one for the load range. The carrier plate of the clutch plate 405 is in turn in essence matched to the contour of the cover plate 438 and incorporates ventilation apertures both radially in the region of the chamber 411 and radially outside this which allow passage of a cooling air current that can then pass along the chamber wall 438 and through ventilation cutouts 470 in the secondary flywheel mass 403 towards the primary flywheel mass 402.

In the twin-mass flywheel 501 illustrated in Figure 13, the tasks and functions of the flanges 415 and 431 and of the plastic component 484 are combined in a single flange 515.

This flange 515 can in turn be manufactured as a cast, forged or sintered part without aftertreatment, which means, for example, that the primary flywheel mass 502 can be fitted without any aftertreatment. Amongst the reasons that the use of a sintered part as flange 515 can prove economic is because a further plastic seal, similar to the plastic part 484 in Figure 12, is superfluous and because, for example, the seat 515b for the bearing 506 and the centring seat 530 for fitting to the output shaft of a combustion engine can be manufactured without aftertreatment.

In Figure 14 too similar reference signs to those in the preceding Figures, though again increased by a further one hundred and beginning with 601, have been used for components performing the same or a similar function.

Figure 14 shows a split flywheel or twin-mass flywheel 601 which has a first or primary flywheel mass 602 which can be connected to an output shaft (not shown) of an engine and also a second or secondary flywheel mass 603. A friction clutch 604 is attached to this second flywheel mass 603 with an intermediate clutch plate 605 whose hub can be accommodated on the drive shaft of a gearbox (not shown) or on a shaft connected to the same. The clutch plate 605 shown here as a rigid item, which stands only as an example, can also be implemented in different embodiments and can, for example, be fitted with a resilient cover.

The two flywheel masses 602 and 603 including the components permanently attached to them are mounted by means of a bearing 606 in the form here of a roller bearing such that they can rotate relative to each other, where said bearing 606 in this example is located radially outside the bores 607 which allow passage of the fastening screws 608 to mount the flywheel device 601 on the output shaft of an engine.

A damping device 609 acts between the two flywheel masses 602 and 603, where said damping device 609 shows, for example, helical compressive springs 610 or leg springs which are located in an annular space 611 which in its radially outer area forms an approximately torus-shaped area 612. The annular space 611 is at least partially filled with a lubricant-like material.

The primary flywheel mass 602 contains a component 613 which in the preferred embodiment is fabricated of sheet metal or drawn where said component 613 serves to attach the split flywheel 601 to the crankshaft of the engine. To this end the component 613 forms on its inner periphery a flange-like area 614 running essentially radially which bears a flange 615 radially inside, whose radially-running areas 615a with the cutouts 607 have aligned bores for the fastening screws 608. The outer ring 617 of the single-row ball bearing 606 shown here is accommodated in an inner sleeve surface or shoulder in the axial end section 615b of the flange 615.

The second flywheel mass 603 contacts the inner ring 616 of the roller bearing of the bearing assembly 606.

After a bulge 618 axially towards the combustion engine, the area 614 which runs essentially radially merges into the starter motor gear 619 which is an integral part of the primary flywheel mass 602. Here too the starter motor gear 619 is manufactured in accordance with a process as described, for example, in connection with Figure 1. The radially inward-facing leg 620 is welded to the sheet-metal component 613 and merges in the region of this welded joint into an axial area 620a which extends away from the combustion engine side and merges in turn at its free end into a radial section 620b that extends in the direction of the rotational axis of the flywheel device 601.

In order to increase the mass moment of inertia of the twinmass flywheel 601 rotating about its rotational axis the primary flywheel mass 602 which can be connected to the engine has a mass ring 621 which in this example is implemented as a casting. The mass ring 621 lies at least partially flush with the side of the sheet-metal component 613 facing away from the combustion engine and borders radially outwardly on the axial section 620a. The attachment of the mass ring 621 within the primary flywheel mass 602 can be made by bordering the section 620b which originally represents an axial extension of the axial section 620a and faces radially inwards after its plastic deformation, as shown in Figure 14.

The flange 615 is connected to and centred on the primary flywheel mass 602. Centring can be carried out, for example, by means of a centring seat 628 which acts on a corresponding cutout in the sheet-metal component 613.

Furthermore the flange 615 has a centring seat 630 on its radially inner side which, when installed, centres the twinmass flywheel 601 on the shaft driving it.

Radially outside its radial area 15a, the flange 15 extends initially axially away from the combustion engine side (as far as the terminal area of the heads of the fastening screws 608 in the example shown) before then extending radially outwards again. In its radially outer area, the flange 615 forms load-application areas 634 for the helical springs 610. The load-application areas 634 are formed by radially-running extensions 615c which project into interspaces between the peripherally-acting energy-storage mechanisms 610. In this regard the flange 615 or its loadapplication areas 634 which lie radially outside the axial end section 615b can also be implemented as described in connection with Figure 1, i.e. matched in particular to the coil ends.

On the other side the energy-storage mechanisms 610 act on load-application areas 636 and 637 which in turn can be divided into various load-application areas analogous to the description for Figure 1. The load-application area 636 is located on a first cover plate 638 which is supported radially inwards on the bearing 606 or here on the inner bearing ring 616 of the single-row roller bearing 606 and which bears the secondary flywheel mass 603 radially outwards. The radially inner area of the cover plate 638 has a shoulder 639 extending axially towards the engine, where said shoulder 639 has an outer diameter on which the inner bearing ring 616 is accommodated. Radially inside the bearing 606 the cover plate runs radially inwards at least in the region of the fastening screws 608 distributed about the periphery.

This radial section 641 contains cutouts 642 which are suitable for accommodating the heads of the fastening screws 608 and in this way holding the fastening screws 608 in an essentially coaxial position relative to the rotational axis of the flywheel device 601 if the flywheel device 601 is not mounted. Radially outside the bearing 606 the cover plate 638 forms a chamber wall of the chamber 611 and at least partially encloses the energy-storage mechanisms 610. This is connected to an outwardly-facing radial section 644 which is permanently connected in the example illustrated by means of a welded joint to a radial section 645 of the second cover plate 646 which is located axially between the cover plate 638 and the cover plate 613. An anti-wear device is 612a is provided between the energy-storage mechanisms 610 and the radially outer areas of the torus-shaped space 612 or the annular chamber 611, where said anti-wear device 612a in this example encloses the helical springs 610 like a dish.

The radial section 644 projects beyond the radial section 645 and is folded at its outer periphery, in similar fashion to that already described, to form a radially inward-facing leg 644a. The radially outer part of the leg 644a lies flush against the radial area 644 while there is a gap between the radially inner free area of the leg 644a and the radial area 644. The leg 644a extends almost to the outer limit of the annular chamber 611. A cooling air current can be routed through the axial gap mentioned, then through axial cutouts 644b in the radial area 644 and radially outwards through the interspace between the mass ring 621 and the secondary flywheel mass 603.

Radially inside the load-application areas 637 the cover plate 646 has an area 648 which is axially stepped in the direction of the combustion engine and flush against which a cup spring 649 lies that is in radial inner contact with the flange 615, thereby forming a radially inner seal for the chamber 611. In this regard the cup spring 649 can be centred both by the cover plate 646 and by the flange 615.

A further cup spring 650 serves to seal the chamber 611 radially inwards between the flange 615 and the cover plate 638. To this end the outer periphery of the cup spring 650 is held centred, while its inner periphery lies flush but elastically against the cover plate 638. In this example the cup spring 650, i.e. the radially inner seal for the chamber 611, is located radially inside the bearing 606.

Such a configuration enables the annular space 611 to be filled with a dry-film or paste-like lubricant such that in operation at least, i.e. when the twin-mass flywheel 601 is rotating, the bearing 606 is in contact with a lubricant.

Here too the twin-mass flywheel 601 together with the clutch unit comprising the clutch 604 and the clutch plate 605 can be formed as a module which is pre-assembled as such, as already described. The clutch plate 605 is then mounted in a pre-centred position relative to the rotational axis between the pressure plate 655 and the friction surface of the secondary flywheel mass 603.

The friction clutch 604 which can be actuated by the cup spring 657 has a hinged device 658 on the side facing the clutch case 660 and a hinged device 659 on the side facing away from the clutch case 660 which are part of an adjustment device 686 to compensate for wear which can be implemented in similar fashion to that described in German published application DE-OS 42 39 291. Leaf spring elements 663 which are connected on one side via a rivet 664 to the housing or case 660 and on the other side via a rivet 665 to the pressure plate 655 are provided for torque transmission purposes and to raise the pressure plate 655. The riveted connection to the pressure plate 655 is made radially inside the friction linings of the clutch plate 605 and radially outside the load-application areas 666a against which the radially outer area of the cup spring 647 lies flush.

Cutouts to allow passage of fastening screws 608 or of a tool to operate the latter, and cutouts for ventilation purposes can also be implemented in the design shown here by analogy with the examples described to date.

The radially outer area of the secondary flywheel mass 603 supports the clutch case 660 which is permanently attached to said mass. The connection between the clutch case 660 and the secondary flywheel mass 603 or with the radial section 644 is made in this case by means of mounting plates 674a which, when not fitted, extend approximately axially and which, after fitting of the secondary flywheel 603 are plastically deformed such that they face radially inwards and engage corresponding cutouts in the secondary flywheel mass 603, thereby forming a permanent connection both axially and peripherally.

The invention is not restricted to the examples illustrated and described but also encompasses variations which can be formed by combinations of individual characteristics or elements described in connection with the various embodiments. The applicant reserves the right to claim protection for further characteristics of essential importance to the invention which to date have only been disclosed in the description.

This application is divided out from copending application 9722834.0 which describes and claims a flywheel device for motor vehicles, with at least a primary and a secondary flywheel mass which are mounted coaxially relative to each other, wherein the primary flywheel mass is connectable with the output shaft of an engine and the secondary flywheel mass can be coupled and uncoupled through a clutch with a gearbox input shaft, a damper with at least one input part and at least one output part is mounted between the two flywheel masses with the input part being connected to one of the flywheel masses and the output part being connected to the other of the flywheel masses and the input and output parts having sockets for energy accumulators which are mounted between the input and output parts and counteract relative rotation of the two flywheel masses, furthermore the two flywheel masses can be mounted as a unit on the output shaft of an engine wherein for this the primary flywheel mass has a radially extending flange-like area for connection to the output shaft of the motor through screw means provided or to be provided radially inside the energy accumulators, the primary flywheel mass has radially outwards a mass ring fitted on and/or moulded on in one piece, furthermore the secondary flywheel mass has a ringshaped friction face for a clutch disc and is formed substantially by a ring-shaped solid component part which extends circumferentially radially outside of the energy accumulators and is supported on a component which is radially inwardly journalled on an axial projection of the primary flywheel mass.

Application 9722834.0 is divided from application 9711996.0 which describes and claims apparatus for transmitting torque comprising; first and second flywheels rotatable with as well as relative to each other about a common axis; and means for opposing rotation of said flywheels relative to each other including at least one damper having at least one coil spring, said coil spring having end convolutions and intermediate convolutions between the end convolutions, said end convolutions of said coil spring respectively having first and second pitches and said first pitches at least approximating said second pitches in substantially unstressed conditions of the coil springs, said at least one damper further comprising an input member driven by one of said flywheels, engaging said end convolutions and being configured to transmit to said end convolutions torque in response to rotation of said one flywheel, said at least one damper further comprising at least one output member arranged to transmit torque from said at least one coil spring to the other of said flywheels in response to rotation of said one flywheel.

Application 9711996.0 is divided from application 9412177.9 which describes and claims apparatus for transmitting torque comprising: a first flywheel adapted to be connected to a rotary output element of a prime mover; a second flywheel rotatable with as well as relative to said first flywheel about a common axis and provided with at least one friction surface disposed at a first radial distance from said axis, said second flywheel adapted to be connected to a rotary input element of a transmission by a friction clutch; a bearing interposed between said flywheels and arranged such that the flywheels are centred relative to one another; means for opposing rotation of said flywheels relative to each other including at least one damper having at least two energy storing elements extending in a circumferential direction of said flywheels at a lesser second radial distance from said axis, said at least two energy storing elements being at least partially confined in said second flywheel as seen in the direction of said axis, and the first and second flywheels being fastenable to the output element together as a unit through fastening means arranged radially inside the energy storing elements.

Claims

1. Flywheel device, more particularly for motor vehicles, with at least a primary and a secondary flywheel mass which are mounted coaxially relative to each other wherein the primary flywheel mass is connectable with the output shaft of an engine and the secondary flywheel mass can be coupled and uncoupled through a clutch with a gearbox input shaft, a damper with an input part and an output part is mounted between the two flywheel masses with the input part being connected to one of the flywheel masses and the output part being connected to the other of the flywheel masses and the input and output parts having sockets for energy accumulators which are mounted between the input and output parts and counteract relative rotation of the two flywheel masses, furthermore the two flywheel masses can be mounted as a unit on the output shaft of an engine wherein for this the primary flywheel mass has a radially extending flangelike area for connection to the output shaft of the engine through screw means provided or to be provided radially inside the energy accumulators, the primary flywheel mass has radially outwards a mass ring fitted on and/or moulded on in one piece, furthermore the secondary flywheel mass has a ring-shaped friction face for a clutch disc and a friction device is mounted radially outside of the energy accumulator.

2. Flywheel device, more particularly for motor vehicles, with at least a primary and a secondary flywheel mass which are mounted coaxially relative to each other through a bearing wherein the primary flywheel mass is connectable with an output shaft of an engine and the secondary flywheel mass can be coupled and uncoupled through a clutch with a gearbox input shaft, a damper with an input part and an output part is mounted between the two flywheel masses with the input part being connected to one of the flywheel masses and the output part being connected to the other of the flywheel masses and the input and output parts having sockets for energy accumulators which are mounted between the input and output parts and counteract a relative rotation of the two flywheel masses, furthermore the two flywheel masses can be mounted as a unit on the output shaft of the motor wherein for this the primary flywheel mass has a radially extending flange-like area for connection to the output shaft of the engine through screw means provided or to be provided radially inside the energy accumulators, the primary flywheel mass has radially outwards a mass ring fitted on and/or moulded on in one piece, furthermore the secondary flywheel mass has an annular friction face for a clutch disc and the bearing is provided radially inside the screw means.

3. Flywheel device as claimed in Claim 1 or Claim 2, wherein the secondary flywheel mass has an annular massive component with an annular friction surface for a clutch disc which is carried by a part formed from sheet material, wherein the sheet material part is journalled on an axial projection of the primary flywheel mass.

4. Flywheel device as claimed in any one of Claims 1 to 3, wherein the component carrying and journalling the secondary flywheel mass can be drivingly coupled through a slip clutch with a component of the secondary flywheel mass which forms the friction surface for a clutch disc.

5. Flywheel device as claimed in any one of Claims 1 to 4, wherein a torque limiter cooperates with one of the flywheel masses and includes a portion which extends in a radial direction relative to at least one component of the torsion vibration damper associated with the one flywheel, which portion can be brought into contact, through friction surfaces, on the one hand with a first part which is connectable with at least one friction lining of a clutch disc and on the other hand with a further part, wherein said first and further parts, the friction linings of the clutch disc and a pressure plate associated with one of the friction linings are arranged essentially radially outside the components of the torsional vibration damper, relative to which said portion extends, and in at least one of these parts a recess is provided for exclusively receiving the portion and the friction surfaces.

6. Flywheel device as claimed in Claim 5, with a torsional vibration damper which has a hub disc and cover elements arranged on both sides thereof to control a torsion spring, characterised in that the portion is formed on the cover elements and the cover elements outside the region of extension of the hub disc are bent towards one another and, in the region of their contact, extend essentially parallel to one another and project into the at least one recess of the parts of the friction clutch.

7. Flywheel device as claimed in Claim 5 or Claim 6, wherein the parts of the friction clutch receiving the portions each form a section of the recess.

8. Flywheel device as claimed in any one of Claims 5 to 7, wherein the radially extending portion engages on at least one side through a friction lining acting as a friction surface with the associated parts of the friction clutch.

9. Flywheel device as claimed in any preceding claim, wherein the output part of the damper is formed by two disclike component parts which are connected to the secondary flywheel mass radially outside of the energy accumulators.

10. Flywheel device as claimed in any preceding claim, wherein the input part or output part of the damper is connected drive-wise to the associated flywheel mass by a torque restrictor.

11. Flywheel device as claimed in any preceding claim, wherein the input part is formed by a flange-like component which is mounted between two side discs forming the damper output part.

12. Flywheel device as claimed in any preceding claim, wherein the bearing is a slide bearing.

13. Flywheel device as claimed in any one of Claims 1 to 11, wherein the bearing is a rolling bearing.

14. Flywheel device as claimed in any preceding claim, wherein the primary flywheel mass has, radially outside of the bearing, recesses for passing through screws by means of which the flywheel device is connectable to the output shaft.

15. Flywheel device as claimed in any preceding claim, wherein the following construction is provided, seen in the radial direction from outside towards the inside - the energy accumulator of the damper, - recesses at least in the primary flywheel mass through which the fastening means can be passed, - the bearing.

16. Flywheel device as claimed in any preceding claim, wherein the primary flywheel mass supports radially inside an axial attachment for bearing the secondary flywheel mass.

17. Flywheel device as claimed in Claim 16, wherein the axial attachment is provided radially inside axial recesses for fixing the flywheel device on the output shaft of a motor.

18. Flywheel device as claimed in Claim 16 or Claim 17, wherein the axial attachment is formed by a separate ringshaped component part of L-type cross-section wherein the radial area of this component part has circumferentially spaced out recesses which are in axial alignment with openings provided in the radially inner area of the flangelike section, primary flywheel mass.

19. Flywheel device as claimed in any preceding claim, wherein the first/primary flywheel mass is formed as a sheet metal construction.

20. Flywheel device as claimed in any preceding claim, wherein the first/primary mass supports a starting gear ring.

21. Flywheel device as claimed in any preceding claim, wherein the radially extending flange-like area of the primary flywheel mass supports radially outside an additional ring-shaped mass body.

22. Flywheel device as claimed in any preceding claim, wherein the radially extending flange-like area of the primary flywheel mass supports radially outside a starting gear ring moulded on in one piece.

23. Flywheel device as claimed in any preceding claim, wherein the radially extending flange-like area of the primary flywheel mass has an axial attachment moulded on radially on the outside.

24. Flywheel device as claimed in Claim 23, wherein the ring-shaped axial attachment and the flange-like area define a space inside which there is at least the damper.

25. Flywheel device as claimed in any preceding claim, wherein a ring-shaped component part forming the secondary flywheel mass and the energy accumulators of the damper mounted radially inside this component part are arranged viewed in the axial direction - at least in part axially one above the other.

26. Flywheel device as claimed in any preceding claim, wherein a component part forming the output part of the damper serves directly for journalling of the two flywheel masses.

27. Flywheel device as claimed in any preceding claim, wherein at least one of the component parts forming the output part and/or input part has recesses for tightening the screws which are to be provided for fitting the flywheel device on an output shaft.

28. Flywheel device as claimed in any preceding claim, wherein the energy accumulator includes compressible helical springs which are supported on the primary flywheel mass and on the annular component which supports the secondary flywheel mass on the primary flywheel mass.

29. Flywheel device as claimed in any preceding claim, wherein the component serving to carry the secondary flywheel mass on the primary flywheel mass has a radial, annular region with axial apertures for fastening the flywheel device on the drive shaft of an engine.

30. Flywheel device as claimed in any preceding claim, wherein a friction device is arranged radially outside the energy accumulator.

31. Flywheel device as claimed in any preceding claim, wherein the bearing is provided radially inside the screw means.