Claims:We claim:
1. An engine (103) for a saddle type vehicle (101), the engine (103) comprising:
a crankshaft (301) coupled to at least one of a manual kick-starting mechanism and an electric start system through a plurality of gears and ratchet mechanism;
a crank case L (201) to accommodate transmission system of an engine;
a cover variator (202) to cover the transmission system of an engine;
a kick starter lever (204) capable of operating a kick starter shaft (205) to rotate said crankshaft (301) to crank the engine (103) through a kick starter mechanism wherein a user kicks the kick starter lever (204) which in turn cranks the engine by transferring the rotational power from the kick starter lever (204) to the crankshaft (301);
a belt-type continuously variable transmission (303) in between a CVT fixed pulley (407) and a movable pulley (410), the CVT fixed pulley (407) and a movable pulley (410) rotatably supported on said crankshaft (301);
the kick starter shaft (205) is guided on a metallic insert (401) and supported on a kick starter shaft housing (411); and
the kick starter shaft housing (411) is being located on a cover fan CVT (420).

2. The engine (103) for a saddle type vehicle (101) as claimed in claim 1wherein the kick starter shaft housing (411) accommodates said kick starter shaft (205) with a transition fit.

3. The engine (103) for a saddle type vehicle (101) as claimed in claim 1 wherein the cover fan CVT (420) is a metallic cover fan CVT (420).

4. The engine (103) for a saddle type vehicle (101) as claimed in claim 1 wherein the cover variator (202) is made of a polymer resin.

5. The engine (103) for a saddle type vehicle (101) as claimed in claim 3 or claim 4 wherein the kick-starter shaft (205) is disposed between the metallic cover fan CVT (420) and the cover variator (202) made of a polymer resin.

6. The engine (103) for a saddle type vehicle (101) as claimed in claim 1 wherein the metallic cover fan CVT (420) is fastened to the cover variator (202).

7. The engine (103) for a saddle type vehicle (101) as claimed in claim 1 or claim 3 wherein the metallic cover fan CVT (420) is disposed between said cover variator (202) and crank case L (201).

8. The engine (103) for a saddle type vehicle (101) as claimed in claim 1 wherein the wherein the cover fan CVT (420) is covered by a metallic crank case L (201) from a first side and through a polymer cover variator (202) from a second side. , Description:TECHNICAL FIELD
[0001] The present subject matter generally relates to a saddle type vehicle with an internal combustion engine. More particularly but not exclusively, the present subject matter relates to a kick starting system for a saddle type vehicle
BACKGROUND
[0002] In an internal combustion engine for a vehicle having belt/chain type transmission, generally a cover variator or transmission cover covers the gears and other power transmission members from at least one of the sides. The cover generally houses a kick starter mechanism. Such a transmission cover for a saddle type vehicle is usually made of a metal or an alloy or a combination of metal alloy & resin. However, due to excessive weight associated with such covers, the transmission system and ultimately the whole engine becomes heavier which in turn results into high cost of the vehicle. Further, since the overall weight of the vehicle increases, the fuel mileage which indicates the distance travelled by the vehicle using a constant volume of fuel, decreases. The typical transmission cover is a complex system made up of at least one set of parts covering a left & right side of a transmission system. The transmission cover typically houses gears for kick starting and CVT (continuously variable transmission) system with wet or dry lubrication to protect the internal parts from environmental hazards like dust, mud, water, etc. for the system to perform with required durability. The surfaces of the transmission cover are typically machined or finished with high surface finish to enable a hermetically sealed encasing for the transmission parts. For low to medium powertrain engines, for a dependable start of the engine, a kick start mechanism with a kick start lever is incorporated which is typically configured on the transmission cover with suitable one-way actuating mechanism to crank the engine to start.
[0003] Further, if the thickness of the transmission cover is reduced to decrease the overall weight, machining of the transmission cover with reduced thickness of the cover becomes challenging. Further, since a kick starter shaft receives impulsive torque through the rider’s feet for cranking the internal combustion engine, if such a kick starter shaft is supported on such a transmission cover with reduced thickness, there is a possibility of breakage of the transmission cover and hence, supporting the kick starter shaft on a cover which can bear the impulsive torque applied through the rider’s feet, also becomes imperative.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The detailed description is described with reference to an embodiment for a saddle type vehicle as a product with the following accompanying figures:
[0005] Figure 1 illustrates an exemplary vehicle with a left side view which incorporates the internal combustion engine as per the present subject matter.
[0006] Figure 2 illustrates a transmission portion of a typical engine as per the present subject matter.
[0007] Figure 3 illustrates a cross sectional view of the engine as per the prior art.
[0008] Figure 4 illustrates a detailed cross-sectional view of the cover fan CVT accommodating the kick starter shaft according to the present subject matter.
[0009] Figure 5 illustrates aspatial comparison of the prior art and the present invention.
Figure 6 illustrates an exploded view of the cover fan CVT assembled on the cover variator according to the present subject matter. DETAILED DESCRIPTION
[00010] A cover variator is a part of an engine which covers various engine parts such as gears, shafts and transmission components. The traditional cover variator for scooter engine houses the parts of the engine’s kick start system. It also carries the inlet and outlet for the cooling air for CVT chamber cooling. In addition, cover variator may also house support bearings for the engine’s transmission shafts. Since, the cover variator is exposed to the environment, the cover variator needs to be made corrosion resistant. Since the cover variator is visible from outside, it also needs to be aesthetically pleasing.
[00011] To reduce the weight of the cover variator and hence the weight of the engine and the overall weight of the vehicle, as an alternate to metallic cover variator, light-weight materials like polymers are now being used to manufacture the cover variator. When a physically weaker material like plastic is used for the transmission cover, the weight of the component is significantly reduced, however, this also leads to reduction in the load bearing capacity of the cover variator.
[00012] The present invention is applicable to all engines with kick-starter mechanism in the transmission cover. Our invention aims to solve the above problem by using a combination of metal and plastic materials in the transmission cover for achieving both the reduced weight of component and the required load carrying capacity. According to the present invention, a cover variator made of a polymer is used to reduce the weight of the cover variator. Further, a cover fan CVT made of either of a metal or an alloy is provided with a kick starter shaft housing used to support the kick-starter shaft and a metallic insert is used to guide the kick starter shaft while rotating and bearing the load induced by the impulsive torque generated through the rider’s feet for cranking the internal combustion engine. The end portion of the kick starter shaft and the inner surface of the kick starter shaft housing are provided with a transition fit which is sufficient enough to allow the rotation of the kick starter shaft within the kick starter shaft housing. It is an object of the present invention to provide an engine with a kick starter mechanism for a two wheeled vehicle, wherein enough rigidity of the engine is ensured to support a kick shaft, reduce the weight of engine and accomplish a reduction in the cost thereof. The present subject matter would be described in greater detail in conjunction with an embodiment of a two wheeled saddle type vehicle with a CVT transmission with the figures in the following description
[00013] As shown in Figure 1, a typical vehicle (101) with a kick starter mechanism includes a rear wheel 102, an engine 103, an air filter 104 for supplying air to the engine 103, a front wheel 105, a front cover 106 to provide shield to rider’s feet against the heat radiated from the engine , a utility box 107 for storing luggage items, a headlamp 108 for providing sufficient visibility during night ride, a side panel 109 to hide the frame parts and provide aerodynamic profile to the vehicle, a front suspension 110 and a rear suspension 111 to provide ride comfort to rider while navigating irregular road surfaces, a pillion handlebar 112 to be held by the rider for positioning himself/herself on the vehicle, a tail lamp 113 for vehicle conspicuity during night riding and a rider seat 114 for rider and/or pillion rider to sit. The engine 103 of the vehicle 101 according to the present invention includes a CVT transmission with a belt/chain drive. The engine 103 is a substantially horizontal engine and comprises of a cylinder head, a cylinder block, and transmission. The engine is capable of being cranked through a kick starter mechanism wherein a user kicks the kick starter lever which in turn cranks the engine by transferring the rotational power from the kick starter lever to the crankshaft.
[00014] Figure 2 illustrates transmission portion of the engine 103 which includes a crank case L 201, cover variator 202, plurality of fasteners 203, kick start lever 204, kick starter shaft 205 and a kick pedal 206. The user applies force on the kick pedal 206 to transmit the rotation to the kick starter shaft 205 through the kick start lever 204. The plurality of fasteners are used to fasten the cover variator 202 to the crank case L 201. A plane X-X’ divides the transmission portion of the engine 103 into am crank case L 201, and a cover variator 202. The crank case L 201 and the cover variator 202 are fastened to each other along this imaginary axis. This imaginary axis follows the mating contour of the crank case L 201 and the cover variator 202. The crank case L 201 and the cover variator 202 encompasses and covers the belt/chain drive, kick starter mechanism and clutch mechanism. The crankcase R (not shown in Figure) comprises the magneto and the fan. According to an embodiment of the present invention, the cover variator 202 is made of a polymer to reduce the weight and cost of the vehicle. In such a vehicle, the crankcase cover L 201 is made up of a metal or a metallic alloy.
[00015] Figure 3 illustrates the engine 103, crank case L 201, cover variator 202, kick starter shaft 205, kick start lever 204, crankshaft 301, clutch mechanism 302, CVT belt 303 and kick starter shaft first housing 304 according to the prior art. According to the prior art, both the crank case L 201 and cover variator 202 are made of metal or an alloy with a cover fan CVT made up of a polymer/resin material and the kick starter shaft is supported in the kick starter shaft first housing 304 formed on the crankcase L 201 at one end and on the cover variator 202 at the other end. In such a case, since both the crank case L 201 and the cover variator 202 are metallic/ alloy, the kick starter shaft gets sufficient support from both the ends to sustain extreme kick-starting torque generated through the rider’s feet during kicking. In such a configuration, since the kick starter shaft first housing 304 is located at a distance D’ which is a larger distance, this configuration of kick starter shaft assembly requires an idler gear 306 and an idler shaft 308 on which the idler gear 306 is mounted for receiving torque from driving gear 305 and transmitting the torque to the driven gear 307. Further, when the kick-starting shaft 205 of the kick-starting mechanism is housed within the kick start first housing 304 according to the prior art, a space corresponding to the length D’ is occupied by the kick-starting mechanism which may further lead to fouling with the clutch 302 during assembly or dis assembly. The use of idler gear on the idler shaft 308 in between the drive gear 305 and the driven gear 307 results into increased number of parts and weight and hence increased size and weight for the crankcase. Due to the need of driving an additional idle gear, the kick-starting shaft 205 requires a stronger housing for support which is provided by the metallic crankcase L 201 according to the prior art. Further, in such a configuration, the cover fan CVT is made up of plastic material. Hence, the kick-starting assembly is covered between the cover variator 202 and the cover fan CVT to protect the kick-starting assembly and the cover fan CVT fastened to the cover variator 202. It is to be noted that a metallic cover variator is the heaviest individual part which supports the kick starter shaft and covers the kick starter assembly while cover fan CVT is lightest part which only covers the kick starter assembly from another side.
[00016] According to our present invention, with an objective to reduce the number of parts, overall size and weight of the engine, the present invention describes a CVT engine wherein the transmission cover is manufactured by using a combination of metal and plastic materials in the transmission cover for achieving both the reduced number of parts, reduced weight of component while maintaining the required load carrying capacity. According to the present invention, the crankcase L 201 is made up of metal/alloy, the cover variator 202 is made of a lighter weight polymer/resin. When heavier weight of an engine is addressed by replacing the heavier part cover variator made up of metal/alloy with light weight polymer/resin, a new challenge of having optimum strength is faced by the engine and its constituent parts. In such a scenario, the cover variator is affected owing to unpredictable kicking force which may be applied on the kick starter lever 204 by the user which may lead to breakage of the cover variator due to transmission of the impulse due to the jerk to the cover variator through the metallic insert 401 which is enmoulded on the cover variator 202. The manual operation of kick starter shaft 205 rotates the crankshaft 301 through kick starter gear and ratchet mechanisms. The kick starter shaft of the kick starter gear mechanism receives impulsive torque through the rider’s feet for cranking the internal combustion engine. At times, the kick starter shaft also undergoes various extreme usage by the rider such as consecutive kicking and rigorous heavy kicking, which requires that the kick starter lever 204 to be provided with enough strength and the kick starter shaft 205 to be provided with support enough to withstand the jerk and impulsive kicks.
[00017] Figure 4 illustrates the kick-starting mechanism of the engine 103 according to our present invention. Figure 4 shows crank case L 201 covering the CVT drive and the kick starter mechanism from one side, cover variator 202 covering the CVT drive and the kick starter mechanism from another side, kick start lever 204 being mechanically coupled to crankshaft 301 through kick starter shaft 205, a metallic insert 401, drive gear 305, driven gear 307, kick starter driven shaft 403, , retainer spring 405, kick starter ratchet 406 and mating ratchet 409. The end portion of the kick starter shaft (205) and the inner surface of the kick starter shaft housing (411) are provided with a transition fit which is sufficient enough to allow the rotation of the kick starter shaft (205) within the kick starter shaft housing (411). A CVT fixed pulley 407 is rigidly coupled to the crankshaft 301 and rotates along with the crankshaft. The CVT fixed pulley 407 is integrally provided with CVT fan 408., A movable pulley 410 slides on the crankshaft with a CVT belt 303 in between the CVT fixed pulley 407 and movable pulley 410.The operation of the kick starter lever 204 results into rotation of the kick starter shaft 205. The kick starter shaft 205 is guided on the metallic insert 401 which is enmoulded on the cover variator at a non-end portion of the kick starter shaft 205; hence, if the kick starter shaft is not supported on a metallic support on at least one of the ends, the cover variator 202 which is made of plastic/resin is prone to get damaged/broken. To achieve the above objective, a first end of the kick starter shaft 205 is housed in a metallic kick start housing 411 on a cover fan CVT 420 and the other end is supported on the metallic insert 401 enmoulded on the cover variator 202. According to the present invention, the idler gear 306 and the idler shaft 308 has been replaced by a drive gear 305 of optimized size and the drive gear 305 is mechanically coupled to the driven gear 307 and the drive gear 305 transmits power to the driven gear 307. Once the driven gear 307 rotates, the retainer spring allows driven gear 307 to get mechanically coupled to the kick starter ratchet 406 and finally, the kick starter ratchet 406 gets coupled to the mating ratchet 409 and rotational torque from the kick starter ratchet 406 is transferred the mating ratchet 409. The rotation of mating ratchet 409 drives the crankshaft 301. The kick starter ratchet (406) rotates and moves forward to mate with the mating ratchet (409) and transfers the required starting rotation to the crankshaft for cranking. Once cranked, and when the user stops applying manual force on the kick starter lever 204, the rotational and translational motion of the kick starter ratchet 406 towards the mating ratchet 409 is completed and the mating ratchet 409 gets disengaged from the kick starter ratchet 406 of the engine 103 and the kick starter ratchet 406 is brought to its normal position by help of the retainer spring 405 which continuously pulls the kick starter ratchet 406 away from the mating ratchet 409 to its normal position.
[00018] A CVT fan 408 is provided on the CVT fixed pulley 407. The CVT fan 408 comprises of plurality of blades either integrally formed on the CVT fixed pulley 407 or fastened to the CVT fixed pulley 407 through fastening means. The cover variator 202 comprises of an annular recess through which air can enter into the area occupied by the CVT belt/chain drive 303 thus thereby providing cooling effect to the area occupied by the CVT chain drive 303. The cover fan CVT 420 forms the inlet for air entry into the area occupied by the CVT chain drive 303.
[00019] Figure 5 illustrates the reduction in size achieved due to this present kick-starting system within the engine layout. As seen from the illustration, according to our present invention, since we are able to provide the kick-starting shaft housed within a housing formed in the cover fan CVT made of metal/alloy, a smaller space corresponding to the length D is required and also the heavier weight cover variator 202 is avoided.
[00020] Further Figure 6 illustrates an exploded view of the kickstarting mechanism. In order to overcome the problems associated with the prior arts, the present invention describes a kick starter shaft guided on a metallic bush/insert 401 and supported inside a kick starter shaft support housing 411 in the cover fan CVT which requires a shorter kick starter shaft and which also results in requirement of a smaller drive gear for the kick starter shaft thereby resulting into requirement of a smaller crankcase L 201 and avoiding fouling of the kick starter mechanism with the clutch mechanism 302. Further, when the kick starter shaft support housing 411 is brought closer to the driven gear 307, avoids fouling with the clutch 302 thereby increasing the volume of air available for cooling the CVT thereby increasing the cooling efficiency of the CVT system.
[00021] According to the present invention, the kick starter shaft 205 is guided on the metallic insert 401. The kick starter shaft 205is supported on the kick starter shaft housing 411. The kick starter shaft housing 411 is being provided on a metallic cover fan CVT 420 thereby providing a sufficient metallic support to the kick starter shaft 205. The cover fan CVT 420 is covered by a metallic crank case L201 from a first side and through a polymer cover variator 202 from a second side. The advantages of reducing the weight of the engine of vehicle is achieved by using the polymer cover variator 202 and the advantage of providing strong support for the kick starter shaft 205 is achieved by providing a kick starter shaft 205 guided on the metallic insert 401 and supported on the kick starter shaft housing 411. This configuration inhibits the kicking impact of kicking the kick starter shaft 205 to reach on to the polymer cover variator 202 and thereby helps in eliminating the probability of breaking off of the polymer cover variator 202 due to kicking impact. Hence, the present invention provides the advantages of reducing number of parts, reducing the weight of the engine and at the same time providing strong support for the kick starter shaft 205.
[00022] Figure 6 further illustrates an exploded view of the CVT engine with cut section of cover fan CVT on the cover variator according to the present subject matter. The exploded view also shows kick starter shaft 205, drive gear 305, kick starter driven shaft 403, retainer spring 405, kick starter ratchet 406, torsional spring 411 and cover fan CVT 420. The cover fan CVT 420 is made of a metal or a metallic alloy and the cover variator 202 is made of polymer/resin. The kick starter housing 411 is formed within the cover fan CVT 420. The cover fan CVT 420 is mounted on to the cover variator 202 using plurality of fasteners and the cover variator 202 is fastened to the crank case L 201. The elements torsional spring 411, the kick starter ratchet 406, the drive gear 305, kick starter shaft 205 and the kick starter driven shaft (403) are covered by the cover fan CVT 420 from one side and the cover variator 202 from the other side. Since the cover fan CVT 420 is axially clamped on the kick starter shaft 205, the cover fan CVT 420 also limits the axial motion of kick starter ratchet 406 and retainer spring 405. The cover fan CVT 420 also helps in retaining grease of the kickstarting mechanism.
[00023] Although the subject matter has been described in considerable detail with reference to certain examples and implementations thereof, other implementations are possible. As such, the scope of the present subject matter should not be limited to the description of the preferred examples and implementations contained therein.