FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
& THE PATENTS RULES, 2003


PROVISIONAL SPECIFICATION
(See section 10; rule 13)
MULTIPLATE WET CLUTCH

HIGH TECHNOLOGY TRANSMISSION SYSTEMS (I) PVT. LTD.,
an Indian Company of K-226, MIDC WALUJ, Aurangabad 431 136, Maharashtra, India
THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION


FIELD OF INVENTION
The present invention relates to a multi plate wet clutch.
Particularly the present invention relates to the cooling of the multi plate wet clutch.
BACKGROUND OF THE INVENTION
A clutch is a mechanism for transmitting rotation, which can be engaged and disengaged. A clutch works because of friction between the friction plates and the reaction plates during operation of the engine. The clutch engages and disengages the engine from the transmission, enabling the driver to start, stop, idle in neutral and shift gears.
During engagement and disengagement of the clutch, an enormous amount of heat energy is generated between the friction plates and the reaction plates, which ultimately leads to an increase in the temperature of the clutch parts. The layer of friction material on friction plate consists of organic materials and tends to burn at elevated temperatures. This further affects the performance of Friction Plate and hence the life of the clutch.
During running of the clutch the temperature of the clutch continuously rises, as the rate of heat generated is more than the rate of heat dissipated. It is observed that, initially temperature rises very rapidly and it goes up to 200°C. This continuous rise in the temperature of the clutch leads to the burning of the friction plates inside the clutch.
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Accordingly, certain devices for cooling were introduced for cooling the clutch assembly. In the internally actuated multi plate wet clutch for two wheelers in the prior art, the clutch is partially oil cooled (mist cooling) by the mist of the oil created by the rotation of clutch and the remaining supply of oil through the gap between the inner diameter of a clutch mounting shaft and the outer diameter of a push rod. In mass production, due to interchangeability of components the tolerances provided on the part varies within the prescribed limits. At minimum and maximum clearances the oil supply quantity through the gap is 0.03 and 37 CC per minute at 4000 rpm respectively. This variable flow of oil is not sufficient for cooling the clutch. Due to continuous rise in the temperature of this clutch, it leads to the burning of the friction plates inside the clutch.
Therefore, there was a need for a clutch to provide a better cooling of the clutch and hence increase the working life of the clutch.
OBJECT OF THE INVENTION
An object of the present invention is to provide efficient cooling of a multi-plate wet clutch.
Another object of the present invention is to increase the life of the friction plates.
Still another object of the present invention is to reduce the cost of maintenance of the multi-plate wet clutch.
Yet another object of the present invention is to improve the durability of the multi-plate wet clutch.
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An additional object of the present invention is to increase the reliability of the multi-plate wet clutch.
Another object of the present invention is to increase the energy throughput rate of the existing clutch.
BRIEF DESCRIPTION OF THE FIGURES
Other aspects of the invention will become apparent by consideration of the accompanying drawings and their description stated below, which is merely illustrative of a preferred embodiment of the invention and does not limit in any way the nature and scope of the invention.
Figure 1 shows the internally actuated multi plate wet clutch for two
wheelers;
Figure 2 shows a perspective view of a push rod of the prior art;
Figure 3a shows the schematic diagram of existing Push rod of the prior art;
Figure 3b shows the sectional view of the push rod of the prior art along line A-A;
Figure 4 a perspective view of a push rod in accordance with the present invention;
Figure 5a shows the schematic diagram a push rod in accordance with the present invention;
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Figure 5b shows the sectional view of the push rod in accordance with the present invention along line B-B;
Figure 6 shows the oil supply per minute through the oil groove of the push rod in accordance with the present invention; and
Figure 7 shows the temperature data after introducing the oil groove on the push rod in accordance with the present invention.
DETAILED DESCRIPTION
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.
Referring to the accompanied drawings, a modified push rod for clutch cooling mechanism, in accordance with this invention is generally indicated by the reference numeral (10a) and is particularly shown in figure 4 to figure 5b of the drawings.
Figure 1 shows the internally actuated multi plate wet clutch for two wheelers. Figure 2 shows a perspective view of a push rod (10) of the prior art. Figure 3a shows the schematic diagram of existing Push rod of the prior art. Figure 3b shows the sectional view of the push rod of the prior art along line A-A. In multi plate wet clutches the heat is produced at every plate to plate junction during engaged and disengaged condition. To cool all of these junctions, special oil passages (2) are typically drilled into the clutch mounting shaft (1) on which they spin. Oil is forced through the shaft (1)
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and out through the gap between push rod (10) and clutch shaft drilled hole (2). The push rod (10) has a broader section (11) and a smaller section (12). The push rod (10) is guided in the center hole of clutch mounting shaft with slide fit tolerance, which allows the axial sliding movement of the push rod during engaged and disengaged condition. Due to this slide fit tolerance, the gap between the push rod (10) and inner center hole on the clutch mounting shaft (1) reduces. This reduce gap is not sufficient for providing higher quantity of the cooling oil to the clutch assembly. Generally, all the pull type clutches are operated through the inner side of clutch shaft (1) drilled hole by push rod and its actuating link (5). If this gap between the push rod (10) and clutch shaft (1) drilled hole is increased, this ultimately leads to oil induced drag.
Figure 4 a perspective view of a push rod in accordance with the present invention. Figure 5a shows the schematic diagram of a push rod in accordance with the present invention. Figure 5b shows the sectional view of a push rod in accordance with the present invention along line B-B. The push rod (10a) has a large section (11) and a small section (12). The push rod (10a) of the present invention is provided with a groove (9) on the large section (11) of the push rod (10a) in order to achieve better circulation of oil in the internally actuated multi plate wet clutch. The machined groove (9) is provided on the push rod (3) provides larger opening area for coolant circulation. The quantity of the oil supply is 38±3 CC per minute at 4000 rpm. The oil supply per minute through oil groove (9) is shown in figure 6. The jet of the oil passing through the groove (9) is directed to fall on the pressure plate (7) and is guided to hub clutch (6) through drilled oil holes (8) provided on outer periphery of the Hub clutch (6). As the oil passes between
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the each clutch plate transfers its heat to the flowing oil and this reduces the temperature of the mating parts and further creates the lubricating film between two rubbing surfaces during engagement of the clutch. The oil collected in the inner periphery of the hub clutch (6) is circulated to plate dutch stack through oil hole (8) provided on inner side of hub clutch (6). The consistent flow of oil helps in effective cooling of the clutch plate stack. Temperature data after introducing the oil passage on the push rod is as shown in the figure 7.
TRIALS
1. The trials were conducted on internally actuated multi-plate wet clutches of 150CC two-wheeler.
2. Following modification has been done :
• Machined axial passage/groove is provided on the push rod
3. The amount of oil delivered through the oil passage/groove was measured at 4000 Engine RPM for one minute time.
4. Burn cycles were conducted on two-wheeler having push rod with the oil groove and without the oil groove. The temperatures of the friction plate were measured and recorded after every I00 burn cycles.
5. At the end of the testing, the life of the clutch without oil passage / groove (injector) is 255-285 burn cycles and the life of the clutch with oil passage/ groove is 900-1050 burn cycles.
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TECHNICAL ADVANTAGES
The push rod with oil groove in accordance with the present invention helps to increase the life of an internally actuated multi plate wet clutch by 2.5-3.5 times the life of the clutch without oil passage. The present invention provides a higher duty cycle with improved durability and reliability through increased energy dissipation rates. The present invention offers the potential to reduce the size of the clutch or enable the operation of the clutch of existing size at higher energy throughput rates.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments 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 changes in the preferred embodiment as well as other embodiments of the invention 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.