FORM 2
THE Patent Act, 1970
(39 of 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13) Semi automatic dual clamp load multiplate wet clutch
Endurance Technologies Pvt Ltd R&D, E 93, MIDC Industrial Area, Waluj, Aurangabad, Maharashtra-431136
The following specification describes the invention

Field of the invention
The present invention relates to a semi automatic dual clamp load multiplate wet clutch and more particularly to a clutch for reducing the handle load at the clutch lever and eliminate the frequent use of clutch lever during starting of vehicle from standstill.
Description of the prior art
An engine transmission assembly of a vehicle includes a clutch assembly for transmission of torque from a driving shaft to a driven shaft. The driving shaft is typically driven by an engine or a motor. The driven shaft is adapted to transmit torque to a drive wheel. The driving shaft is typically connected to a plurality of friction plates whereas the driven shaft is connected to a plurality of clutch plates of the clutch assembly or vice versa.
The plurality of friction plates and the plurality of clutch plates are alternately arranged such that a clutch plate is disposed between a pair of adjacent friction plates. The plurality of friction plates and plurality of clutch plates are clamped together tightly by application of clamping load applied by a plurality of coil springs, when the clutch is in an engaged condition. The plurality of coil springs applies a clamping load on the friction plates and the clutch plates to tightly hold them together, thereby permitting transmission of torque from the drive shaft to the driven shaft. For disengaging the clutch, a force has to be applied against the clamping load of the springs to move the friction plates away from the clutch plates to discontinue torque transmission there between and permit free rotation of the friction plates.

In the case of a two-wheeler such as a motor cycle, the force that has to be applied against the clamping load of the springs is supplied to the springs by actuating or pressing a handlebar lever. For efficient torque transmissions by the clutch, the clamping load has to be increased, which in turn aggravates the handlebar load.
Further, fixed leverage ratios of the handlebar lever and load characteristics of the coil springs further aggravates the handlebar load, thereby increasing discomfort and fatigue of a driver of a two-wheeler. Further the discomfort and fatigue of the driver of the two-wheeler results in indecent clutch handling and therefore reduced clutch life. The prior art discloses a number of clutch assemblies that increase the clamping load for torque transmission.
For example, the multi-plate wet clutch disclosed in our pending Indian application 720/MUM/2008 utilizes floating wheel clutch for accommodating mis-alignments and errors to improve clutch engagement linearity, which in turn reduces judder and rattling of the multi-plate wet clutch.
A transmission system disclosed in our pending application 1167/MUM/2006 is used for vehicles, particularly two-wheelers. The transmission system reduces judder and rattle and involves use of a push rod, a ball and a recess cup provided within the clutch assembly. The transmission system also uses a judder washer and judder spring in its friction stack subassembly.
Again, US Patent 5,184,704 issued on February 9, 1993 discloses a conversion for a clutch of a motor vehicle which uses a conventional Belleville spring to bias a pressure plate and clamp a clutch disc between the pressure plate and the flywheel of the vehicle. In this disclosure, the frictional linings of the conventional clutch are substituted by frictional linings which are located at optimum geometric spacing, and

which have from 30-70 percent less surface area forfrictional engagement than that conventionally furnished with the clutch. The disclosure is particularly applicable to upgraded performance cars, e.g., the new line of SLP cars being introduced by some manufacturers.
Also, conventionally used clutch assemblies achieve efficient torque transmission either by increasing envelope size of the clutch or by compromising with the comfort of the driver of the two-wheeler.
Accordingly, there is a need of a clutch assembly that achieves efficient torque transmission with reduced efforts for operating the clutch, thereby reducing the fatigue of the driver of the two-wheeler.
Hence, the principle object of the present invention is to provide a dual clamp-load multi-plate wet clutch assembly that reduces handle load while still increasing torque capacity of the clutch by increasing the clamp load proportional to the torque of the
engine.
Another object of the present invention is to provide a dual clamp-load multi-plate wet clutch assembly that eliminates the necessity of using clutch lever during initial vehicle take off and stopping.
An object of the present invention is to provide a dual clamp-load multi-plate wet clutch assembly that reduces the effort required for operating a clutch.
Another object of the present invention is to provide a dual clamp-load multi-plate wet clutch assembly that is convenient to operate, thereby increasing comfort of a driver of a two-wheeler.

Another object of the present invention is to provide a dual clamp-load multi-plate wet clutch assembly that improves vehicle take-off characteristics.
Yet another object of the present invention is to provide a dual clamp-load multi-plate wet clutch assembly that achieves efficient torque transmission without compromising with comfort of a motor-cyclist.
Still another object of the present invention is to provide a dual clamp-load multi-plate wet clutch assembly that that is adapted to achieve efficient torque transmission without increasing envelope size of the clutch assembly.
Another object of the present invention is to provide a dual clamp-load multi-plate wet clutch assembly that may be modified to suit lower to higher capacity vehicle requirements.
Brief description of the invention
In accordance with one aspect of the present invention a semi automatic dual clamp-load multi-plate wet clutch assembly is disclosed. The semi automatic dual clamp-load multi-plate wet clutch assembly includes a clutch housing assembly, a plate clutch assembly, a thrust-washer, conical spring, Poly-tetra-fluoro-ethylene (PTFE) coated washer and recess cup assembly.
The clutch housing assembly includes a clutch housing , a primary engine gear, plurality of damper springs, damper plate, a plain washer, a conical slotted disc spring, plurality of rivets, a plurality of centrifugal masses, a plurality of fulcrum-pins, a plurality of center-pins and a plurality of external circlip.

The plate clutch assembly includes a fixed hub assembly or fixed pressure plate assembly, a moving hub assembly, plurality of cylindrical pins, plurality of friction plates, plurality of plates, at least one conical slotted disc spring, a plurality of plain washers, a judder spring, a judder washer, plurality of counter-sunk head screws and a - holder-plate.
There is provided a multiplate wet clutch assembly mounted on a gear box input shaft of a vehicle, the clutch assembly having a clutch housing with a plurality of input friction plates for receiving and transmitting engine torque to a plurality of out steel plate mounted on a moving hub clutch in a operative clamped configuration of the clutch assembly, the arrangement comprising: clamping means to generate a first clutch engaging load and a second clutch engaging load to clamp the moving hub clutch to the fixed hub clutch and in turn the input friction plate and the output steel plates, the first clutch engaging load is provided by a plurality of centrifugal masses mounted on the said clutch housing to maintain the moving clutch assembly in an engaging configuration in their operative compressed state of the spring, the second engagement force is achieved through the torque sensing mechanism which is proportional to the engine torque and depends on moving hub helix design.
Typically, the pluralities of fulcrum pins are fixed onto an inner face of the clutch housing at desired periphery to hold the plurality of centrifugal masses through center pins.
Typically, the fixed pressure plate assembly includes an aluminum fixed pressure plate, a fixed hub insert, a plurality of rivets, a plurality of locating holes and a hub insert.

Typically, in the fixed pressure plate assembly the fixed hub insert is attached to aluminum fix pressure plate by means of rivets.
Typically, the aluminum hub clutch is constrained between moving hub helix insert and flange cup by riveting the aluminum hub clutch to the moving hub helix insert by using rivets.
In accordance with the present invention there is provided a method of distribution of clutch engaging load for a multi plate wet clutch mounted on a gear box input shaft of a vehicle, the method comprising the steps of:
• The first clutch engagement force is achieved through centrifugal force action for vehicle take off or crawling, so it will eliminate the frequent use of clutch lever for starting condition.
• The second engagement force is achieved through the torque sensing mechanism which is proportional to the engine torque and depends on moving hub helix design.
Brief description of the drawings
The invention will now be explained in relation to the accompanying drawings, in which:
Figure 1 illustrates a full cross-sectional view of a complete clutch assembly, in accordance with one embodiment of the invention;
Figure 2(a) illustrates a top view of a clutch housing assembly, in accordance with one embodiment of the invention;

Figure 2(b) illustrates a sectional view of a clutch housing assembly along section line B-B of Figure 2(a);
Figure 3(a) illustrates detail arrangement of plate clutch assembly, in accordance with an embodiment of Figure 1;
Figure 3(b) illustrates a sectional view of the plate clutch assembly along a section line C-C as illustrated in Figure 3(a);
Figure 4(a) illustrates detail arrangement of fixed pressure plate assembly, in accordance with one embodiment of the invention;
Figure 4(b) illustrates a sectional view of the fixed pressure plate assembly along a section line D-D as illustrated in Figure 4(a).
Figure 5(a) illustrates a detail arrangement of a moving hub assembly, in accordance with one embodiment of the invention;
Figure 5(b) illustrates a sectional view of the moving hub assembly along a section line E-E as illustrated in Figure 5(a);
Figure 6 is a graph illustrating variation of clutch clamping load and clutch release load with engine speed; and
Figure 7 a graph illustrating variation of engine torque along clutch axis, clutch torque capacity and pressure on friction materia! with engine speed.
Detailed description of the invention
The invention will now be described with reference to the accompanying drawings which do not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.

A dual clamp-load multi-plate wet clutch assembly of the present invention reduces handle load while increasing torque capacity of the clutch by increasing the clamp load proportional to the torque of the engine. More specifically, the dual clamp-load multi-plate wet clutch assembly reduces effort applied by a driver of a two-wheeler for operating a clutch of the two-wheeler during a gear changing activity. The dual clamp-load multi-plate wet clutch assembly eliminates the necessity of frequently using clutch lever during initial vehicle take off and stopping. The dual clamp-load multi-plate wet clutch assembly reduces force exerted by the driver of the two-wheeler for pressing a handlebar lever of the two-wheeler to operate the clutch, thereby significantly reducing fatigue of the driver of the two-wheeler. The dual clamp-load multi-plate wet clutch assembly of the present invention can be used for any vehicle that uses a hand clutch lever for operating a clutch of the vehicle during a gear changing activity.
Referring to Figure 1, the complete clutch assembly 100 includes a clutch housing assembly 110, a plate clutch assembly 120, a thrust-washer 130, conical spring 140, Poly-tetra-fluoro-ethylene (PTFE) coated washer 150 and recess cup assembly 160.
Referring to Figure 2, the clutch housing assembly 110 includes clutch housing 101, a primary engine gear 102, a plurality of damper springs 103, damper plate 104, a plain washer 105, at least one conical slotted disc spring 106, a plurality of rivets 107, a plurality of centrifugal masses 108, a plurality of fulcrum-pins 109, a plurality of center-pins 111 and a plurality of external cir-clip 112.
Referring to Figure 3, the plate clutch assembly 120 includes a fixed hub assembly or fixed pressure plate assembly 121, a moving hub assembly 122, a plurality of cylindrical pins 123, a plurality of friction plates 124, a plurality of plates 125, at least

one conical slotted disc spring 126, a plurality of plain washers 127, a judder spring 128, a judder washer 129, a plurality of counter-sunk head screws 131 and a -holder-plate 132.
Referring to Figure 2 and Figure 3 of the accompanying drawings, the plurality of fulcrum pins 109 are fixed onto an inner face 113 of the clutch housing 101 at desired periphery to hold the plurality of centrifugal masses 108 through center pins 111. The centrifugal masses 108 are allowed to rotate on rotation axis of the center pin 111 during rotation of clutch housing 101. The centrifugal masses 108 are configured so as to automatically engage with moving hub assembly 122 as the engine speed crosses a predetermined threshold. The conical slotted disc spring 126 is used to keep the clutch disengaged till threshold speed of about 1400 rpm is achieved. In addition, the clutch may be manually disengaged and subsequently re-engaged without a delay in torque transfer.
Figure 4 of the accompanying drawings illustrates the fixed pressure plate assembly
121. The fixed pressure plate assembly 121 includes an aluminum fixed pressure
plate 133, a fixed hub insert 134, a plurality of rivets 135, a plurality of locating holes
136 and a hub helix insert 137. In the fixed pressure plate assembly 121 the fixed
hub insert 134 is attached to aluminum fix pressure plate 133 by suitable joining
means such as by means of rivets 135. In case of the complete clutch assembly 100
of the present invention, the fixed pressure plate assembly 121 drives the input shaft
of the gear box (not shown in figure) similar to as in case of the conventional
clutches.
Figure 5 of the accompanying drawings illustrates the moving hub clutch assembly
122. The moving hub clutch assembly 122 includes an aluminum hub clutch 143,

hub helix insert 137, flange cup 138 and plurality of rivets 139. The aluminum hub clutch 143 is constrained between moving hub helix insert 137 and flange cup 138 by riveting the aluminum hub clutch 143 to the moving hub helix insert 137 by using rivets 139. The moving hub clutch assembly 122 further includes a helix guide 141 and a hub helix insert face insert 142.
According to preferred embodiment, a multi-plate clutch assembly 100 for a two-wheeler or a three wheeler includes a drive portion, generally referred as housing clutch assembly 110, which is mounted on input shaft of gear box (secondary shaft not shown in figure), connected to engine crankshaft pinion (not shown in figure) through clutch housing primary engine gear 102. The multi-plate clutch assembly 100 further includes a driven portion generally referred as plate clutch assembly 120 and configured to drive the secondary gears of a transmission (not shown in figure) and ultimately rear wheel of a two-wheeler. The driven portion includes two subassemblies i.e. the fixed pressure plate assembly 121 which is interlocked with gear box input shaft splines and externally locks from other side with specially designed nut (not shown in Figure) and the moving hub assembly 122 which is guided on the fixed pressure plate assembly 121 and is allowed to move axially from first position to second position. The moving hub assembly 122 is coupled to rotate with the fixed pressure plate assembly 121 through cylindrical pins 123 and the helix guide 141. A release holder plate 132 is bolted to moving hub assembly 122 and this bolted assembly is capable of axial movement from at least first position to a second position on fixed pressure plate assembly 121. A plurality of drive clutch plates (friction plate) 124 coupled for rotation with drive portion (clutch housing assembly) 110 and a plurality of driven clutch plates (steel plate) 125 coupled for rotation with the driven portion (plate clutch assembly) 120 are arranged, in an alternating

manner, between the fixed pressure plate assembly 121 and moving hub assembly 122.
The fixed pressure plate assembly 121 and moving hub assembly 122, the plurality of friction plates 124, the plurality of plates 125, the judder spring 128, the judder washer 129, the plurality of conical springs 126, the plain washer 127 and the release holder plate 132 clamped together with help of plurality of counter sunk head screws 131 as shown in Figure-3. At the same time a plurality of cylindrical pins 123 are assembled in the pin locating holes 136 of the fixed hub insert 134 and then suitably placed into the moving hub insert helix groove 141. Each of the plurality of plates 125 and the holder plate 132 is configured of steel. However, the present invention is not limited to a particular material for configuring the plurality of plates 125 and the holder plate 132.
To arrest the centrifugal outward motion of the cylindrical pins 123 during actual working of the clutch, a flange cup 138 is provided as shown in the Figure-5. Additionally, at least one conical slotted disc spring 126 and a plain washer 127 are placed in between fixed pressure plate assembly 121 and moving hub assembly 122 to balance the axial force created by the centrifugal mass 108 such that said conical slotted disc spring 126 and plain washers 12 avoids the engagement of the clutch at the idling rpm. But when the vehicle is throttled above the idling rpm it will continuously increase the clamp load proportional to the engine speed. When the engine rpm will above the idling rpm, the clamp load generated by the centrifugal mass 108 will enough to overcome the conical slotted disc spring stiffness and engages the clutch, this will propel the vehicle from the standstill.

Generally, most of the two-wheelers utilize manually controlled multi-plate clutches and a multiple speed transmissions to achieve the desired maximum grade-ability and maximum vehicle speed. The manually controlled clutches are frequently engage and disengage to change gear position from neutral position (starting and stopping application) to different gear ratio as per speed demand. However, the clutch is not only used by rider of two-wheeler for shifting the gear position, but is also used to control the overall speed and power delivery of the two-wheeler by interrupting engine torque from reaching the rear wheel. To eliminate this frequent use of clutching operation, clamp load is split into the two clutch engagement forces.
The first clutch engagement force is achieved through centrifugal force action for vehicle take off or crawling, so it will eliminate the frequent use of clutch lever for starting condition. In this configuration, the centrifugal force is used to apply the required pressure for keeping the clutch in engaged position. The advantage of the centrifugal clutch is that no need to operate clutch lever for vehicle take off. The clutch is operated automatically depending upon the engine speed. This means that vehicle can be stopped in gear without stalling the engine. Similarly while starting, the driver can first select the gear, put the vehicle into the gear and simply give movement to the accelerator on handle bar not shown in figure. This makes the driving operation very easy.
The second engagement force is achieved through the torque sensing mechanism which is proportional to the engine torque and depends on moving hub helix design. As the engine torque increases, tangential force WT on the clutch housing assembly increases. The axial component of this tangential force fulfills the desired clamp load requirement. As per clamping force requirement we can vary the helix angle design to get desired second clamp load. The length of helical slot has been computed in

such a way that the wear and tear of the friction material and release stroke is taken care of. Refer to Figure 6 and Figure 7 for combined clamping load for different engine speed.
In use, the driver of either a two or three wheeler wishing to operate the clutch for changing gear has to decelerate it first. The deceleration of the two-wheeler causes self clamping device comprising the cylindrical pin 123 and helix guide 141 to release the clamping force applied on the plurality of friction plates 124 and plurality of plate clutches 125. At this point, clamping force imparted by the plurality of centrifugal masses and self clamping device are acting on the plurality of friction plates 124 and plurality of plate clutches 125 is low, thereby requiring a comparatively less amount of force for complete disengagement of the clutch. The driver of the two-wheeler now has to apply a less effort for pressing the handlebar lever, thereby reducing fatigue of the driver of the two-wheeler
The multi-plate wet clutch assembly eliminates the constraints and limitations of the prior multi-plate wet clutch. The multi-plate wet clutch assembly utilizing dual clamp load of the present invention is adapted to reduce effort required for operating the
clutch assembly. More specifically, the multi-plate wet clutch assembly utilizing dual
clamp load reduces the handle lever load by a great extent. Further, multi-plate wet clutch assembly of the present invention is convenient to operate, thereby increasing comfort of the driver of the two and three wheeler. Furthermore, the multi-plate wet clutch assembly utilizing dual clamp load is adapted to improve vehicle take off characteristic. The multi-plate wet clutch assembly eliminates frequent use of clutch release lever during starting and stopping of the vehicle. The multi-plate wet clutch assembly of the present invention can be modified according to requirement for catering two-wheelers of different capacities, more particularly, the torque sensing

mechanism (e.g. helical slot) of the multi-plate wet clutch assembly can be varied to enable the multi-plate wet clutch assembly to be used for higher capacity vehicles. The multi-plate wet clutch assembly improves vehicle take off characteristic. The multi-plate wet clutch assembly improves life of power-train component.
While considerable emphasis has been placed herein on the particular features of this invention, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

Claims:
1. A multiplate wet clutch assembly mounted on a gear box input shaft of a vehicle, said clutch assembly having a clutch housing with a plurality of input friction plates for receiving and transmitting engine torque to a plurality of output steel plates mounted on a moving hub clutch in an operative clamed configuration of the clutch assembly, said arrangement comprising: clamping means to generate a first clutch engaging load and a second clutch engaging load to clamp the moving hub clutch to the fixed hub clutch and in turn the input friction plates and the output plates.
2. The multiplate wet clutch assembly as claimed in claim 1, wherein clamping means for said first clutch engaging load is provided by a plurality of centrifugal masses mounted on the said clutch housing.
3. The multiplate wet clutch assembly as claimed in claim 1, wherein clamping means for said second clutch engaging load is provided through a torque sensing mechanism that is proportional to engine toque.
4. The multiplate wet clutch assembly as claimed in claim 1, wherein at least one conical disc spring is provided between the moving hub and said fixed pressure plate assembly to balance the axial force created by the centrifugal mass and the reaction force generated by engine torque such that it avoids the engagement of clutch at idling rpm.
5. The multiplate wet clutch assembly as claimed in claim 3, wherein said torque sensing mechanism is provided by a moving hub helix design.
6. The multiplate wet clutch assembly as claimed in claim 1, wherein pluralities of fulcrum pins are fixed onto an inner face of the clutch housing at desired periphery to hold the plurality of centrifugal masses through center pins.

7. The multiplate wet clutch assembly as claimed in claim 1, wherein when said vehicle is throttled above the idling rpm, the clamp load generated by the centrifugal mass overcomes the conical slotted disc spring stiffness and engages the clutch and consequently propels the vehicle from standstill.
8. The multiplate wet clutch assembly as claimed in claim 1, wherein said multiplate wet clutch assembly is mounted on a gear box input shaft of a two wheeler or a three wheeler.
9. A vehicle having said multiplate wet clutch assembly as claimed in claim 1.