FIELD OF THE INVENTION:
The present invention relates to the field of torque transmission devices and more particularly to torque transmission devices for a clutch assembly of motor vehicles.
BACKGROUND OF THE INVENTION:
A torque transmission device is commonly used in mechanical machines and particularly in motor vehicles for transferring torque produced by an engine of a vehicle to a driven shaft which connects drive wheels of the vehicle. Typically, the torque transmission device comprises a torque input element, a torque output element, elastic members, a drive plate, a retainer plate, bushings, and the like to perform various functions during transmission operations.
In a clutch assembly of the vehicle, a clutch includes the torque input element which is coupled to a flywheel of the engine and the torque output element which is coupled to an input shaft of a gear box. The torque input element of the clutch primarily transfers power to different transmitting elements, which are operatively connected to the input shaft of a gear box. The clutch assembly further includes elastic members like springs to absorb torsional vibrations occurring during the event of power generation and power transmission. The use of elastic members help to absorb the vibrations produced during the torque transmission and also restricts the axial movement of the parts of the torque transmission device.
The prior art KR101448113 discloses a clutch disc for a vehicle. The clutch disc generates hysteresis by forming a friction portion by means of a direct contact between a hub and a retainer plate. The clutch disc of the said prior art reduces the frictional components and directly generates hysteresis between the hub and the retainer plate to reduce the torsion vibrations during the torque transmission.
Prior art GB2303414 discloses a solution for compensating the problem of misalignment between an axis of rotation of an input member ant an axis of rotation of an output member. This solution discloses a clutch disc which supports on its outer circumference two friction linings with an input part rotationally engaged with a retainer plate of a torsion vibration damper. Springs of the main torsion vibration damper transmit a torque between the retainer

plates and a drive plate. The drive plate serves as the output part of the torsion vibration damper and transfers a torque on the output side through a further torsion vibration damper to the hub of the clutch disc. A conical spacer is used between the hub and a retainer plate as an additional component in the clutch assembly. However, the additional component not only adds to the complexity of the arrangement but also increases the manufacturing costs and increase the free play in the transmission device.
Thus, there is a requirement of a torque transmission device which can mitigate the above-mentioned drawbacks of the prior arts.
OBJECT OF THE INVENTION
It is a principal object of the present invention to provide a torque transmission device.
It is another object of the present invention to take the misalignment between the axis of the torque input element and the axis of the torque output element into account in the design of a torque transmission device.
It is another object of the present invention to allow a movement not only circumferential between an input element and an output element of a torque transmission device.
It is another object of the present invention to reduce the free play in the torque transmission device.
It is another object of the present invention to improve the efficiency of the torque transmission device.
It is yet another object of the invention to provide a torque transmission device which is simple in structure and cost effective.
SUMMARY OF THE INVENTION
According to an embodiments of the present invention, a torque transmission device comprising a torque input element comprising a friction disc, a torque output element comprising a hub, a first retainer plate in contact with the friction disc, a plurality of primary dampers arranged axially around the hub, a drive plate coupled to the hub and a second retainer plate coupled to the first retainer plate.

According to an embodiment of the present invention, said first retainer plate has a first sloped portion and said hub has a second sloped portion such that the first sloped portion of the first retainer plate is in a contact with the second sloped portion of the hub to allow a alignment between an axis of rotation of said torque input element and the axis of rotation (X) of said torque output element-According to an embodiment of the present invention, said first retainer plate comes in contact with the drive plate to create a frictional interface.
According to an embodiment of the present invention, said first slopped portion and said second slopped portion are conical.
According to an embodiment of the present invention, said first slopped portion and second slopped portion are spherical.
According to an embodiment of the present invention, a first spring washer is arranged between said second retainer plate and said drive plate.
According to an embodiment of the present invention, a second spring washer is arranged between the second retainer plate and the hub.
According to an embodiment of the present invention, the hub has primaiy teeth which are arranged in a radially external portion of the hub for coupling said hub and said drive plate.
According to an embodiment of the present invention, the primary teeth allow a translation in the axial direction of the drive plate relative to the hub.
According to an embodiment of the present invention, the hub has secondary teeth which are arranged in a radially internal portion of the hub for coupling the input shaft of the gearbox.
According to an embodiment of the present invention, the first slopped portion is arranged axially adjacent to the primary teeth of the hub.
According to an embodiment of the present invention, no play is left circumferentially between the primary teeth of the hub and complementary teeth of the drive plate.

BRIEF DESCRITPION OF THE DRAWINGS
FIG. 1 illustrates a front view of a torque transmission device according to an embodiment of the invention.
FIG.2 illustrates an isometric view of the torque transmission device according to an embodiment of the invention.
FIG.3 illustrates a sectional view of the torque transmission device along section AA' according to an embodiment of the invention.
FIG. 4 illustrates another isometric view of the torque transmission device according to an embodiment of the invention.
FIG. 5 illustrates an exploded view of the torque transmission device according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The detailed description set forth below in connection with the appended drawings is intended as a description of the present invention and is not intended to represent the only way in which the present invention may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. The embodiment provided herein is for the purpose of filing the complete specification.
FIG. 1 illustrates a front view of a torque transmission device (01) according to an embodiment of the invention. The torque transmission device (01) of a clutch assembly is in contact with a flywheel (not shown) coupled to an engine (not shown) of a vehicle through a torque input element. The torque input element may be a friction disc (02) which makes a contact with a flywheel (not shown) coupled to the engine. The flywheel may also be a dual mass flywheel which is coupled to the engine. The friction disc (02) is arranged between a pressure plate (not shown) and the flywheel and it is pressed by the pressure plate to towards the flywheel for transmitting the torque. The pressure plate is pressed by a spring arrangement to make contact with the friction disc (02).

As per an embodiment of the present invention, the torque transmission device (01) comprises a torque input element which may be a friction disc (02), a first retainer plate (04), a second retainer plate (14), a drive plate (16), a set of springs (06), spring washers (18, 20), and a friction washer 42. The torque transmission device further comprises a torque output element comprising a hub (08). All the components of the device as disclosed by the invention are held together by a coupling means such as bearings and the like. The hub (08) is coupled to an input shaft of a gear box. The torque transmission device (1) of the present invention is coupled with an input shaft of the gear box for transmission of torque to an axle of the vehicle. Accordingly, the input shaft may be a clutch shaft, splined shaft or a transmission input shaft.
As per an embodiment of the present invention, the friction disc (02) i.e. the torque input element is fixed to the first retainer plate (04) of the device, which transfers the torque to the drive plate (16) through the springs (06). The drive plate (16), the first retainer plate (04) and the second retainer plate (14) includes openings (22, 24, 26) wherein the springs, such as helicoidal springs, are inserted. The first and second retainer plates (04, 14) axially hold the springs (06) by means of walls (44, 45, 46, 47) which are arranged along a radially inner side of the openings and along a radially outer side of the openings. The circumferential openings (22,24, 26) are axially aligned in the rest position of the device.
The first retainer plate (04) further includes a first sloped portion (28) towards the hub of the device. According to the embodiment, the first sloped portion (28) may be at a raised surface with respect to the remaining surface of the first retainer plate (04).
Similarly, the hub (08) includes a second sloped portion (30) towards the first retainer plate (04). The first sloped portion (28) of the first retainer plate (04) and the second sloped portion (30) of the hub (8) are in contact (32) with each other to form a conical shape and thus, eliminating a need for an additional component for the torque transmission device. The said conical contact (32) compensates the problem of misalignment between an axis of rotation of the torque input element and an axis of rotation (X) of the torque output element, which results in effective power transmission.
The conical contact allows a relative movement of the first retainer plate (04) with respect to the hub (08), not only in circumferential direction but also in the axial direction. The conical contact allow a tilting of the retainer plate (04) with respect to the hub (08) due to the

misalignment of the axis of rotation of the torque input element and the axis of rotation (X) of the torque output element.
As per an embodiment of the present invention, the hub (8) of the present invention has a central opening to receive a splined end of the input shaft. A radially inner portion of the hub (08) has a set of secondary teeth (12) to securely hold the input shaft therein and the radially outer portion of the hub (08) has a set of primary teeth (10) for allowing coupling with the drive plate (16). The input shaft has a set of teeth complimentary to the secondary teeth (12) of the hub (08) for a secured contact and after assembling the torque transmission device (01) with the clutch assembly, the input shaft starts rotating according to the rotational speed of the torque transmission device (01). Similarly, the drive plate (16) has a set of teeth complimentary to the primary teeth (10) of the hub (08) for coupling the drive plate (16) to the hub (08). The drive plate (16) is moveable along axial direction relative to the hub (08).
The hub (08) is surrounded by springs (06) to absorb the torsional vibrations occurring during the torque transmission. The springs (06) may be helicoidal springs which are capable of absorbing the jerks or shocks and helps in effectively transmitting the torque to other parts of the torque transmission device (01). The first retainer plate (04) is provided with slots or openings (22) to axially secure the springs (06) between the first and the second retainer plates (04, 14). The springs (06) are circumferentially arranged around the hub (08) and are retained between the retainer plates (04, 14). The springs (06) deforms elastically in a circumferential direction to allow an effective rotational movement between the torque input element and the torque output element.
FIG.2 illustrates an isometric view of the torque transmission device (01) according to an embodiment of the invention, wherein the first retainer plate (04) is axially arranged with respect to the drive plate (16) through a direct contact (34).
According to the embodiment, the torque transmission device (01) has a first spring washer (18) arranged axially between the drive plate (16) and the second retainer plate (14) and a friction washer (42) arranged axially between the spring washer (18) and the drive plate (16). The spring washer (18) forms a base on the second retainer plate (14) and accordingly pushes the friction washer (42) and the drive plate (16) towards the first retainer plate (04) to make direct contact (34) between them.

The direct contact (34) creates a frictional interface between the drive plate (16) and the first retainer plate (04).
The direct contact (34) portion of the first retainer plate (04) is flat and offset axially with respect to the openings of the first retainer plate in order to ensure axial centring of the drive plate with respect to the springs (06).
Thanks to the direct contact between the first retainer plate (04) and the drive plate (16), there is no free play related to the mounting of a friction washer with the retainer plate.
Thus, the said flat contact (34) substantially reduces or eliminates free play during the operation of the torque transmission device (01) and a smooth transmission of power or torque is therefore provided.
The hub (08) has the second sloped portion such that the first sloped portion of the first retainer plate (04) is in a contact with the second sloped portion (30) of the hub (08) to allow a alignment between an axis of rotation of said torque input element and the axis of rotation (X) of said torque output element.
The first spring washer (18) may be a plastic washer, metal washer or any other elastic washer as known in the art.
According to an embodiment of the present invention, the torque transmission device (01) has a second spring washer (20) arranged between the hub (08) and the second retainer plate (14). The primary purpose of placing the second spring washer (20) between the hub (08) and the second retainer plate (14) is to provide a push to the second sloped portion (30) of the hub (08) towards the first sloped portion (28) of the first retainer plate (04). The shapes of the first sloped portion (28) and the second sloped portion (30) are made complimentary to each other to make a conical contact (34) thereof The second spring washer (20) may be a plastic washer, metal washer or any other elastic washer previously known in the art. As seen in Fig. 3 a bushing is inserted radially between the second retainer plate and the hub, and axially between second elastic washer and the hub.
The conical contact (34) of the first retainer plate (04) and the hub (08) furnishes an articulation adapted to the misalignment between the axis of the torque input element and the axis of the torque output element.

According to an embodiment of the present invention, the first sloped portion (28) of the first retainer plate (04) and the second sloped portion (30) of the hub (08) are conical. The conical portions provide a conical contact (34) to possibly correct misalignment between the axis of rotation of the torque input and the torque output element, The first and the second sloped portions (28, 30) may be made spherical for a similar purpose as described above.
As shown in FIG. 2, the hub (08) of the present invention has a set of secondary teeth (12) arranged on a surface of inner side of hollow portion of the hub (08). That is, the secondary tooth (12) is arranged in a radially internal portion of the hub (08). The secondary teeth and the teeth of the input shaft are designed complimentary to each other for providing a coupling between the input shaft of the gear box and the hub (08). The shaft of the torque output element is inserted inside the hollow portion of the hub (08) so that the teeth (12) of the hub (08) make a secured contact with the teeth of the torque output element.
On an external portion of the hub (08), primary teeth (10) is provided to hold the drive plate (16). That is, the primary teeth (10) is arranged in a radially external portion of the hub (08) for coupling with the drive plate (16). Accordingly, no free play is circumferentialiy left between the primary teeth (10) of the hub (08) and a complementary teeth of the drive plate (16).
The secondary teeth (12) and the primary teeth (10) are made tapered or of any other shape as known previously in the art and similarly, the teeth of the input shaft and the drive plate (16) are complimentarily designed.
The hub (8) is surrounded by the springs (06) to absorb.the vibrations produced during the power transmission. The springs (06) are mounted between the first retainer plate (04) and the second retainer plate (14).. The springs may be heavy dampening springs as already known in the art. The major advantage of using the springs (06) is to absorb the torsional vibrations produced during the events of power generation and power transmission. The design and arrangement of the springs (06) may be a set of springs surrounding the hub as shown in FIG. 1 to 5.
FIG.3 illustrates a sectional view of the torque transmission device (01) along section AA' according to an embodiment of the invention, wherein the first sloped portion (28) of the first retainer plate (04) is arranged axially adjacent to the primary teeth (10) of the hub (08). During the torque transmission, the second spring washer (20) pushes the sloped portion (30)

of the hub (08) towards the sloped portion (28) of the first retainer plate (04) and accordingly a contact portion (32) is created. The contact portion forms a conical contact and the problem of the misalignment between the torque input element and the torque output element is taken into account. The first spring washer (18) arranged between the second retainer plate (14) and the drive plate (16), pushes the drive plate (16) towards the first retainer plate (04) to create a frictional interface between them.
Thus, the friction interface or a direct contact of the drive plate (16) and the first retainer plate (04) solves a problem of free play in the torque transmission device (01) of the prior art which include additional frictional washer mounted on the retainer plates. Accordingly, the first retainer plate (04) of the present invention has integrated functions of hysteresis, drive plate centring, and conical holdings.
FIG. 4 illustrates another isometric view of the torque transmission device (01) according to an embodiment of the invention, wherein the second retainer plate (14), and the first retainer plate (04) are coupled to each other with coupling means like rivets. The second retainer plate (14) has a flat surface around the hub (08). A function of the second retainer plate (14) is to provide a push to the drive plate (16) towards the first retainer plate (04) for creating a friction interface. The springs (06) arranged between the retainer plates also allows an axial alignment of the second retainer plate (14), drive plate (16) and the first retainer plate (04).
FIG. 5 illustrates an exploded view of the torque transmission device (01) according to an embodiment of the invention, wherein the first sloped portion (28) of the first retainer plate (04) having a raised portion around the hub (08) is shown. The first sloped portion (28) makes a conical contact with the second sloped portion (30) of the hub (08). A set of spring openings (22) are provided on the first retainer plate (04) to hold the springs (06). Accordingly, the drive plate (16) and the second retainer plate (14) are also provided with a complimentary set of openings (24, 26) which are axialiy aligned with the spring openings (22) of the first retainer plate (04). The springs (06) are elastically deformable in a circumferential direction of the rotation axis of the torque transmission device (01).
Also, the first retainer plate has slots (36) to receive the coupling means (38) such as flat shaped rivets. The bearings are used for coupling the parts of the torque transmission device (01) of the present invention.

As per an embodiment of the present invention, secondary springs may be arranged between the torque output element and the drive plate. Thus a pre-damper which comprises an auxiliary retainer plate coupled in rotation with the drive plate can be introduced in the torque transmission device
As per an alternate embodiment of the present invention, the torque transmission device has no pre-damper and no circumferential play between the drive plate and the hub, and the torque transmission device is coupled to a Dual Mass Flywheel (DMF) of an engine.
The engine may be an internal combustion engine or an external combustion engine. The assembly of the torque transmission of the present invention may be coupled to the clutch assembly as previously known in the prior art.
Various modifications to these embodiments are apparent to those skilled in the art from the description and drawings herein. The principles associated with the various embodiment defined herein may be applied to other embodiments. Therefore, the description is not intended to be limited to the embodiments shown along with the accompanying drawings but is to be provided the broadest scope consistent with the principles and novel and inventive features describe/disclosed or suggested herein. Any modifications, equivalent substitutions, improvements etc. within the spirit and principle of the present invention shall all be included in the scope of protection of the present invention.

We claim:
1. A torque transmission device (01) comprising:
- a torque input element comprising a friction disc (02); a torque output element comprising a hub (08);
- a first retainer plate (04) in contact with the friction disc (02);
- a plurality of primary dampers (06) arranged axially around the hub (08);
- a drive plate (16) coupled to the hub (08); and
- a second retainer plate (14) coupled to the first retainer plate (04);
wherein,
said first retainer plate (04) has a first sloped portion (28); and
said hub (08) has a second sloped portion (28) such that the first sloped portion (28) of the first retainer plate (04) is in a contact with the second sloped portion (30)ofthehub(08).
2. The torque transmission device (01) as claimed in claim 1, wherein said first retainer plate comes in contact with the drive plate (16) to create a frictional interface (34);
3. The torque transmission device (01) as claimed in claim 1, wherein said first slopped portion (28) and said second slopped portion (30) are conical.
4. The torque transmission device (01) as claimed in claim. 1, wherein said first slopped portion (28) and second slopped portion (30) are spherical.
5. The torque transmission device (01) as claimed in claim 1, wherein a first spring washer (18) is arranged between said second retainer plate (14) and said drive plate (16).
6. The torque transmission device (01) as claimed in claim 1, wherein a second spring washer (20) is arranged between the second retainer plate (14) and the hub (08).

7. The torque. transmission device (01) as claimed in claim 1, wherein the hub has primary teeth (10) which are arranged in a radially external portion of the hub (08) for coupling said hub and said drive plate
8. The torque transmission device (01) as claimed in claim 7, wherein the primary teeth allow a translation in the axial direction of the drive plate relative to the hub (08).
9. The torque transmission device (01) as claimed in claim 1, wherein the hub has secondary teeth which are arranged in a radially internal portion of the hub for coupling the input shaft of the gearbox.
10. The torque transmission device (01) as claimed in claim 1, wherein the first slopped portion (28) is arranged axially adjacent to the primary teeth (10) of the hub (08).
11. The torque transmission device (01) as claimed in claim 1, wherein no play, is left circumferentially between the primary teeth (10) of the hub (08) and complementary teeth of the drive plate (08).