Title of Invention

INTEGRATED DAMPER AND WET CLUTCH ASSEMBLY

Abstract

Integrated damper and wet clutch assembly is provided having a torsional damper for dampening torsional vibration from engine to transmission. A miltidisc wet clutvh assembly is also drivingly connected to the torsional damper with damper cover in-between.The wet clutch assembly includes a plurality of drive plates connected to a drive drum,a plurality of driven plates connected to a driven drum.The damper and wet clutch assembly is integrated into a common housing of an automotive transmission and is provided with an internaly or externaly driven cooling system.

Full Text

FORM2 THE PATENTS ACT, 1970 (39 of 1970) and Patent Rules 2003 COMPLETE SPECIFICATION (See section 10; rule 13) 1. Title - INTEGRATED DAMPER AND WET CLUTCH ASSEMBLY 2. Applicant - MAHINDRA & MAHINDRA LTD 1, GATEWAY BUILDING, APOLLO BUNDER, MUMBA1100001 AN INDIAN COMPANY. The following specification particularly describes the nature of this invention and the manner in which it is to be performed FIELD OF INVENTION The present invention relates to integrated damper and wet clutch assemblies for automotive transmissions wherein a damper cover is mounted on engine flywheel to transfer axial load of clutch release mechanism to flywheel, reducing the effective mass of the flywheel thereby keeping its total moment of inertia constant. DESCRIPTION OF BACKGROUND ART Most automotive transmissions are equipped with a flywheel, which is attached to the engine output shaft. A dry clutch assembly is provided adjacent to the flywheel to provide friction coupling between the flywheel and the transmission input shaft. The clutch assembly is engaged through a pressure plate, which gets the driven plate into frictional contact with the flywheel causing the driven plate to rotate along with the flywheel. A manually operable clutch release mechanism is provided to allow a vehicle operator to selectively disengage the clutch assembly by releasing the pressure applied to the driven plate by the pressure plate. A clutch cover is typically mounted on the flywheel to cover the clutch assembly. As the clutch release mechanism is actuated, the frictional contact between the flywheel and the driven plate is relieved and the driven plate of clutch assembly is free to rotate relative to the flywheel. Release of the frictional contact between the flywheel and the driven plate allows the transmission to be shifted to a higher or lower gear ratio and allows the vehicle to be stopped without stalling the engine. Conventional dry clutch assemblies use a single driven plate which is highly susceptible to excessive wear and may require several replacements during the normal service life of a vehicle. US Patent No. 5,788,037 discloses an integrated clutch transmission in automotive application as means to overcome problems with conventional clutch assemblies. A damper and clutch assembly is provided having a torsional 2 damper for providing a dampened connection to an engine output shaft and having inertia member connected thereto. A multi-disc clutch mechanism also drivingly connected to the torsional damper. The clutch mechanism includes plurality of drive plates connected to drive drum, a plurality of driven plates connected to driven drum and an inertia member connected to drive drum. The damper and clutch housing integrated into the housing of automotive transmission and is provided with a force air cooling system and an inside to outside lubrication system. Though this arrangement takes the axial load through clutch cover, it does not contribute to the flywheel moment of inertia thereby adding undesirable weight to the system. US Patent No. 6666313 describes a dual mass flywheel and clutch system for minimizing torsional vibration level during engine start-up and during low speed engine operation where the rotational moment of the inertia of clutch input assembly is minimized to raise the torsional natural frequency of the dual mass clutch system above the engine firing frequency when the clutch is disengaged to reduce the level of torsional vibration during engine start-up. After engine startup, the duel mass clutch system is engaged and torsional natural frequency of the clutch system return to a lower frequency due to the rotation of clutch output assembly thereby effectively reducing the torsional vibration level in the vehicle driveline in a normal manner. In this arrangement the axial load is taken by the engine face plate and the clutch housing face plate, and does not contribute to the flywheel moment of inertia thereby adding undesirable weight to the system. Solutions disclosed in the prior art have a major limitation that they cannot be accommodated in existing conventional dry clutch systems especially in those cases which have severe space limitations. There is a long standing need for integrated damper and wet clutch assemblies, for automotive transmissions, configured to transfer axial load of the clutch 3 release mechanism to flywheel, without adding undesirable weight to the system within, given space constraints. SUMMARY OF THE INVENTION The main object of the invention is to provide an integrated damper and wet clutch assemblies for automotive transmissions to transfer axial load of clutch release mechanism to flywheel without adding undesirable weight to the system and accommodating the configuration within the existing available space in the housing. Another object of the invention is to provide a damper cover as an alternative to a conventional partition wall to transfer axial load of clutch release mechanism to engine flywheel. Another object of the invention is to prevent flow of cooling / lubricating media towards the torsional damper. It is yet another object of the invention to provide the integrated damper and clutch assembly with an internally or externally driven cooling system. It is another object of the invention to provide an integrated damper and wet clutch assembly replacing conventional dry clutch assemblies with minimal changes despite being structurally simple, cost effective to manufacture and easy to mass produce. It is yet another object of the invention to provide an integrated damper and wet clutch assembly wherein a device for circulating cooling / lubricating media is located inside the housing so that it can optionally be driven internally by the rotating damper cover mounted on the flywheel. 4 DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a cross-sectional view of an integrated damper and wet clutch assembly according to the present invention ; The present invention relates to an integrated damper and wet clutch assembly comprising a torsional damper, damper cover, wet clutch assembly, clutch release mechanism and means of cooling and lubricating system, wherein the damper and wet clutch assembly are operably linked to the engine flywheel and input shaft of multi-speed transmission, the assembly being enclosed in a common housing. In a preferred embodiment of the invention, the flywheel (5) is mounted on an engine output shaft (not shown), which is used to transfer power developed by the engine to the transmission. A torsional damper (2) is mounted on flywheel (5) using fastening and locating devices, such that the torsional damper is concentric with flywheel (5). A drum shaped damper cover (3) is mounted on flywheel (5) enclosing the torsional damper (2) in a manner to enable transfer of axial forces to the flywheel (5) in the clutch "release" mode, thereby protecting torsional damper (2) from axial loads. Torsional damper (2) includes a base plate connected to the engine flywheel (5), which takes power from the engine flywheel (5) and transmits to an intermediate drive shaft (8) through a hub (9) which in turn transmits it to wet clutch assembly (4). One end of intermediate drive shaft (8) is supported at the centre of flywheel (5) and other end at the central opening of a damper cover (3), by means of radial bearings and is concentric with flywheel (5), torsional damper (2) and damper cover (3). A axial thrust bearing (11) is provided between the damper cover (3) and outer drum (10) of wet clutch assembly (4) to transfer thrust to damper cover (3) and to allow relative motion between them with minimal frictional losses in the clutch "release" mode. 5 Multi-plate wet clutch assembly (4) in the vicinity of the axial thrust bearing (11) comprises of an outer drum (10), an inner drum (12) and a multi-disc wet clutch pack (13), wherein the outer drum (10) is concentric with respect to the intermediate drive shaft (8), the inner drum (12) is concentric with respect to the input shaft (6) of multi-speed transmission and the multi-disc wet clutch pack (13) operably installed in between the outer drum (10) and inner drum (12). Multi-disc wet clutch pack (13) includes a plurality of drive plates that are alternately interleaved with driven plates wherein the said drive plates take power from outer drum (10) and said driven plates are mounted on inner drum (12) for transmission of power to input shaft (6) of the multi-speed transmission, in the clutch "engage" mode. A spring-biased thrust mechanism, (14) concentric with respect to the input shaft (6) of multi-speed transmission, exerts clamp force on wet clutch pack (13) to maintain the wet clutch assembly (4) in an "engaged" mode. Clutch release mechanism is operated to shift the multi-plate wet clutch pack (13) in the "released" mode. Multi-plate wet clutch pack (13) is provided with cooling system (not shown) that includes a device for circulating cooling / lubricating media, cooling media flow lines and passages. Cooling media flows from the circulating device, common housing (7) and release sleeve (15) to the center of inner drum (12). The inner drum (12) is provided with radial openings on its external surface to facilitate outward movement of the cooling media, which is then collected at the bottom of common housing (7) for re-circulation. When the operator presses the clutch pedal (not shown), the linkages (not shown) operate the release bearing (16) to move in axial direction towards the flywheel (5) exerting force on the fingers of spring-biased trust mechanism (14) 6 causing release of clamp force on the wet clutch pack (13) thereby disengaging the clutch. This axial load generated during clutch "release" action, acts on the outer drum (10), which is further transferred to the damper cover (3) through axial thrust bearing (11) and then finally transferred to the flywheel (5). This configuration safeguards the torsional damper (2) from getting loaded. In one of the embodiment of the invention, the central opening of the damper cover (3) is provided with an additional sealing arrangement in between an intermediate drive shaft (8) and damper cover (3) to prevent flow of cooling media towards torsional damper (2). In another embodiment, a forced cooling system is internally driven by the integrated damper and wet clutch assembly (1) wherein a driving member is rotatably mounted on the damper cover (3) to drive a device for circulating cooling / lubricating media. In another embodiment of the invention, accessories such as cooler, pump are located in the free space available inside the common housing (7) and around damper cover (3), thereby avoiding external protrusion of these accessories. 7 We claim ; 1. An integrated clamper and wet clutch assembly, comprising a torsional damper comprising damping member, mounted on flywheel, hub rotatably connected to an intermediate shaft; a drum like structured damper cover with mounting provision on the said flywheel and a provision at the center for supporting said intermediate shaft wherein the said damper cover encloses the said torsional damper; multi-plate wet clutch assembly comprising outer drum, an inner drum rotatably mounted on input shaft of multi-speed transmission, a multi-disc wet clutch pack; thrust bearing provided between the said damper cover and outer drum of the said wet clutch assembly to transfer thrust to damper cover; a spring-biased thrust mechanism; wherein the said damper cover transfers axial forces generated during clutch release action to the flywheel via the said thrust bearing, thereby protecting the said torsional damper from axial loads. 2. An integrated damper and wet clutch assembly, as claimed in claim 1 wherein the torsional damper includes a base plate, concentric to engine flywheel, which takes power from the engine flywheel and transmits to an intermediate drive shaft through a hub which in turn transmits it to wet clutch assembly, wherein one end of said intermediate drive shaft is supported at the centre of flywheel and other end at the central opening of a damper cover, by means of radial bearings and is concentric with flywheel, torsional damper and damper cover, a thrust bearing being provided between the damper cover and outer drum of wet clutch assembly to transfer thrust to damper cover and to allow 8 relative motion between them with minimal frictional losses in a clutch "release" mode. 3. An integrated damper and wet clutch assembly as claimed in claims 1-2 wherein the multi-plate wet clutch assembly comprises of an outer drum, an inner drum and a multi-disc wet clutch pack, wherein the outer drum is concentric with respect to the intermediate drive shaft, the inner drum is concentric with respect to the input shaft, and the multi-disc wet clutch pack operably installed in between the intermediate shaft and the input shaft. 4. An integrated damper and wet clutch assembly as claimed in claims 1 and 4, wherein the multi-disc wet clutch pack includes a plurality of drive plates that are alternately interleaved with driven plates wherein the said drive plates have lugs on outer periphery to take power from outer drum and said driven plates have internal splines meshing with external splines of the inner drum for transmission of power to input shaft of the multi-speed transmission, in the clutch "engage" mode. 5. An integrated damper and wet clutch assembly as claimed in claims 1-4 wherein the said spring-biased thrust mechanism release has a finger concentric with respect to the input shaft of multi-speed transmission on the outer drum exerts clamp force on wet clutch pack to maintain the wet clutch assembly in an "engaged" mode with the clutch release mechanism operated to shift the multi-plate wet clutch pack in the "released" mode. 6. An integrated damper and wet clutch assembly as claimed in claims 1-5 wherein the multi-plate wet clutch pack is provided with cooling system that includes an oil pump, cooling oil flow lines and passages, such that the 9 cooling oil flows from the oil pump, common housing, release sleeve to the center of inner drum wherein the inner drum is provided with radial openings on its external splines to facilitate movement of the cooling oil out which is collected at the bottom of common housing for re-circulation. 7. An integrated damper and wet clutch assembly as claimed in claims 1-7 wherein the forced cooling system is internally driven by the integrated damper and wet clutch assembly in which a driving member is rotatably mounted on the damper cover to drive a device for circulating cooling / lubricating media. 8. An integrated damper and wet clutch assembly as claimed in claims 1-7, wherein the central opening of the damper cover is provided with an additional sealing arrangement in between an intermediate drive shaft and damper cover to prevent passage of cooling / lubricating to the torsional damper. 9. An integrated damper and wet clutch assembly as claimed in claims 1-8, wherein accessories such as cooler, pump are located in the free space available inside the common housing and around damper cover thereby avoiding external protrusion of these accessories. Date: July 31st 2006 ABSTRACT Integrated damper and wet clutch assembly is provided having a torsional damper for dampening torsional vibration from engine to transmission. A multi-disc wet clutch assembly is also drivingly connected to the torsional damper with damper cover in-between. The wet clutch assembly includes a plurality of drive plates connected to a drive drum, a plurality of driven plates connected to a driven drum. The damper and wet clutch assembly is integrated into a common housing of an automotive transmission and is provided with an internally or externally driven cooling system.

Documents:

1217-MUM-2006-ABSTRACT(AMENDED)-(19-6-2007).pdf

1217-mum-2006-abstract(granted)-(28-3-2008).pdf

1217-mum-2006-abstract.doc

1217-mum-2006-abstract.pdf

1217-MUM-2006-ASSIGNMENT(2-8-2006).pdf

1217-MUM-2006-CANCELLED PAGES(19-6-2007).pdf

1217-mum-2006-claim.doc

1217-MUM-2006-CLAIMS(AMENDED)-(19-6-2007).pdf

1217-mum-2006-claims(granted)-(28-3-2008).pdf

1217-mum-2006-claims.pdf

1217-MUM-2006-CORRESPONDENCE 16-6-2008.pdf

1217-MUM-2006-CORRESPONDENCE(2-8-2006).pdf

1217-MUM-2006-CORRESPONDENCE(IPO)-(24-3-2008).pdf

1217-mum-2006-correspondence-others.pdf

1217-mum-2006-correspondence-received.pdf

1217-mum-2006-description (complete).pdf

1217-mum-2006-description(granted)-(28-3-2008).pdf

1217-MUM-2006-DRAWING(AMENDED)-(19-6-2007).pdf

1217-mum-2006-drawing(granted)-(28-3-2008).pdf

1217-mum-2006-drawings.pdf

1217-MUM-2006-FORM 1(1-8-2006).pdf

1217-mum-2006-form 2(granted)-(28-3-2008).pdf

1217-MUM-2006-FORM 2(TITLE PAGE)-(1-8-2006).pdf

1217-mum-2006-form 2(title page)-(granted)-(28-3-2008).pdf

1217-MUM-2006-FORM 26(2-8-2006).pdf

1217-mum-2006-form-1.pdf

1217-mum-2006-form-18.pdf

1217-mum-2006-form-2.doc

1217-mum-2006-form-2.pdf

1217-mum-2006-form-26.pdf

1217-mum-2006-form-3.pdf

1217-mum-2006-form-5.pdf

1217-mum-2006-form-9.pdf

1217-mum-2006-granted.pdf

1217-MUM-2006-REPLY TO FIRST EXAMINATION REPORT(19-6-2007).pdf

abstract-1.jpg