Claims:I/We Claim:
1. A powertrain (400) for a vehicle (100) comprising
an internal combustion engine (180); said internal combustion engine (180) includes a crank case (201);
a transmission assembly; said transmission assembly including a clutch assembly (207) and a gear box (217); said gear box (217) includes a gear shift assembly (304); and a multistage gear reduction assembly (303);
wherein,
said gear shift assembly (304) includes a shift drum (312), an electric machine (300), and electric machine gear assembly (311); said shift drum (312) being operatively coupled to said electric machine (300) through an electric machine gear assembly (311) and,
wherein,
a horizontal first plane (XX’) splits the crankcase (201) into a top region and a bottom region; wherein, said bottom region of said crankcase (201) being filled with lubricating oil, and said horizontal first plane (XX’) substantially passes in close proximity of central axis of said shift drum (312), said electric machine (300), and said electric machine gear assembly (311).
2. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein said multistage gear reduction assembly (303) includes:
an intermediary shaft (305), said intermediary shaft (305) holds a plurality of drive gears (307), and
a secondary shaft (306), said secondary shaft (306) holds a plurality of driven gears (308);
wherein,
said plurality of drive gears (307) being coupled to said plurality of driven gears (308), and said plurality of driven gears (308) being operably coupled to said gear shift drum (312).
3. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein said multistage gear reduction assembly (303) being disposed substantially equally on both top and bottom side of said horizontal first plane (XX’).
4. The powertrain (400) for a vehicle as claimed in claim 2, wherein said plurality of drive gears (307) and said plurality of driven gears (308) being freely rotatably installed on corresponding said intermediary shaft (305) and said secondary shaft (306).
5. The powertrain (400) for a vehicle as claimed in claim 1, wherein said electric machine gear assembly (311) being installed on a bush (403), wherein said bush (403) being installed on a tertiary shaft (404).
6. The powertrain (400) for a vehicle as claimed in claim 1, wherein said electric machine (300) being a gear shift motor (300).
7. The powertrain (400) for a vehicle as claimed in claim 1, wherein said electric machine (300) includes an output shaft (309), said output shaft (309) being configured to have a plurality of external splines (310), wherein, said external splines (310) being meshed with said electric machine gear assembly (311).
8. The powertrain (400) for a vehicle as claimed in claim 2, wherein said electric machine gear assembly (311) includes at least a first gear (311a), at least a second gear (311b), and at least a third gear (311c).
9. The powertrain (400) for a vehicle (100) as claimed in claim 8, wherein said at least third gear (311c) being meshed with at least a portion of a shift drum (312).
10. The powertrain (400) for a vehicle (100) as claimed in claim 8, wherein said first gear (311a) being meshed with said plurality of external splines (310) on said output shaft (309).
11. The powertrain (400) for a vehicle (100) as claimed in claim 8, wherein said second gear (311b) operably connects said first gear (311a) and third gear (311c).
12. The powertrain (400) for a vehicle (100) claimed in claim 1, said transmission assembly being enclosed in said crankcase (201);
wherein,
said crankcase (201) comprises of a top portion, a bottom portion, and a plurality of side portions, wherein said plurality of side portions are substantially vertical and being configured to extend between said top portion and said bottom portion;
wherein,
one of said plurality of side portions include a first region (300A) and a second region (300B).
13. The powertrain (400) for a vehicle (100) as claimed in claim 12, wherein said second region (300B) being configured to receive at least a portion of said electric machine (300) in a recess (405) provided in said second region (300B).
14. The powertrain (400) for a vehicle (100) as claimed in claim 12, wherein said crankcase (201) includes a crankcase LH (201A) extending leftwardly in said internal combustion engine (180) width direction and a crankcase RH (201B) extending rightwardly in said internal combustion engine (180) width direction; wherein, said plurality of side portions include a crankcase LH (201A) side portion and a crankcase RH (201B) side portion.
15. The powertrain (400) for a vehicle (100) as claimed in claim 14, wherein said electric machine (300) being disposed in at least said crankcase LH (201A) side portion or said at least crankcase RH (201B) side portion or both.
16. The powertrain (400) for a vehicle (100) as claimed in claim 12, wherein said crankcase RH (201B) extends in rightward direction, and a crankcase LH (201A) extends in leftward (LH) of said internal combustion engine (180),
wherein,
said crankcase LH (201A) being covered by a housing cover to make powertrain (400) leak proof and enables effective lubrication.
17. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein said shift drum (312) being disposed ahead of said electric machine (300) when viewed from top of said internal combustion engine (180).
18. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein distance between a central axis of said electric machine (300) and a central axis of said shift drum (312) being a predetermined distance (d), wherein said predetermined distance (d) ranges from 50mm to 70mm.
19. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein distance between an outer edge of said electric machine (300) and an outer edge of said shift drum (312) being a predetermined distance (d1), wherein said predetermined distance (d1) ranges from 50mm to 70mm.
20. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein diameter of said electric machine (300) ranges from 45mm to 60 mm.
21. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein diameter of said shift drum (312) ranges from 35mm to 55mm.
22. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein said electric machine (300) being detachably attached to a crankcase RH (201B) side portion or crankcase LH (201A) side portion, or both, using attachment means, wherein said attachment means includes a plurality of bolts (312).
23. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein said transmission assembly includes one or more centrifugal clutch for automatic clutch actuation based on engine (180) operating speed.
24. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein said gear shift assembly (304) being disposed in proximity of an oil sump (212).
25. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein an oil pump assembly (402) being substantially disposed below said horizontal first plane (XX’).
26. A straddle type two wheeled vehicle (100) including:
a frame assembly;
a powertrain (400) powertrain (400) for a vehicle (100) comprising
an internal combustion engine (180); said internal combustion engine (180) includes a crank case (201);
a transmission assembly; said transmission assembly including a clutch assembly (207) and a gear box (217); said gear box (217) includes a gear shift assembly (304); and a multistage gear reduction assembly (303);
wherein,
said gear shift assembly (304) includes a shift drum (312), an electric machine (300), and electric machine gear assembly (311); said shift drum (312) being operatively coupled to said electric machine (300) through an electric machine gear assembly (311) and,
wherein,
a horizontal first plane (XX’) splits the crankcase (201) into a top region and a bottom region; wherein, said bottom region of said crankcase (201) being filled with lubricating oil, and said horizontal first plane (XX’) substantially passes in close proximity of central axis of said shift drum (312), said electric machine (300), and said electric machine gear assembly (311).
27. A three wheeled vehicle including:
a chassis frame structure; and
a powertrain (400) for a vehicle (100) comprising:
an internal combustion engine (180); said internal combustion engine (180) includes a crank case (201);
a transmission assembly; said transmission assembly including a clutch assembly (207) and a gear box (217); said gear box (217) includes a gear shift assembly (304); and a multistage gear reduction assembly (303);
wherein,
said gear shift assembly (304) includes a shift drum (312), an electric machine (300), and electric machine gear assembly (311); said shift drum (312) being operatively coupled to said electric machine (300) through an electric machine gear assembly (311) and,
wherein,
a horizontal first plane (XX’) splits the crankcase (201) into a top region and a bottom region; wherein, said bottom region of said crankcase (201) being filled with lubricating oil, and said horizontal first plane (XX’) substantially passes in close proximity of central axis of said shift drum (312), said electric machine (300), and said electric machine gear assembly (311). .
28. The powertrain (400) for a vehicle (100) as claimed in claim 1, wherein said gear box (217) being disposed integrally inside said crankcase (201) on said power train (400) so as to configure said multistage gear reduction assembly (303) and said gear shit assembly (304) inside the lubricated region of said crankcase (201).

, Description:TECHNICAL FIELD
[0001] The present subject matter described herein generally relates to a vehicle, and particularly but not exclusively relates to a power train of a vehicle.
BACKGROUND
[0002] The chassis of a vehicle acts as a skeleton of the vehicle. The powertrain of the vehicle can be called as the musculature system of the vehicle.
[0003] The powertrain encompasses every component that converts the engine’s power into movement of the vehicle. This includes an engine, a transmission system, driveshaft, differentials, axles; basically, anything from the engine through to the rotating wheels of the vehicle.
[0004] A drivetrain, as the name suggests, is the name given to the group of components that drive the wheels of the vehicle. But unlike the powertrain, it typically refers to everything that comes after the engine. So, all the components in between the engine and wheels that produce, develop or assist drive, make up the drivetrain of the vehicle.
[0005] The transmission system of the vehicle includes a gearbox and a clutch, which transmits and converts power from the engine into rotational force for the wheels. The clutch engages or disengages the crankshaft of the engine from the gears as they are shifted up, down, or into neutral. This is particularly important when the vehicle is not in motion and it is desired to keep the engine idling. As without the clutch, the engine’s rotation would result in a shuddering halt, and stall.
[0006] Gears are the way of best harnessing and optimising the engine’s power when the vehicle is in motion. A low gear (first or second) produces more torque at lower speeds, while a high gear produces less torque at higher speeds to keep the vehicle rolling along rapidly.
[0007] Typically, in a multi-track vehicles which are rear-wheel-drive vehicle or all-wheel drive vehicles, the driveshaft also called as a propeller shaft, is a long rotating shaft that runs all the way down the centre of the vehicle, bridging the gap between the engine or the transmission and the wheels by sending rotating force to the wheels of the vehicle. The differential allows the driven wheels to rotate at different speeds, increasing grip. Without a differential, the driven wheels would be locked together and forced to spin at the same speed. The axle is the shaft on which a wheel or a gear rotates.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The detailed description is described with reference to an embodiment of a vehicle with an internal combustion engine along with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[0009] Fig. 1 illustrates a side view of a vehicle in accordance with an embodiment of the present invention.
[00010] Fig. 2 illustrates a side view of a power train of a vehicle, including an internal combustion engine, according to an embodiment of the present subject matter.
[00011] Fig. 3 illustrates a portion of a power train of a vehicle, according to an embodiment of the present subject matter.
[00012] Fig. 4a illustrates an isometric view of a conventional motorcycle engine, including a crankcase.
[00013] Fig. 4b illustrates an isometric view of a power train of a vehicle as per an embodiment of the present subject matter.
[00014] Fig. 5 illustrates an isometric view of a power train of a vehicle as per an embodiment of the present subject matter.
[00015] Fig. 6a to Fig. 6b illustrates left and right-side views of the crankcase LH of a vehicle as per an embodiment of the present subject matter.
[00016] Fig 7 illustrates a gear box of a vehicle along with the electric machine, for example a gear shift motor, in accordance with an embodiment of the present subject matter.
[00017] Fig. 8 illustrates a gear shift assembly as per an embodiment of the present subject matter.
[00018] Fig. 9 illustrates a horizontal cut section of the crankcase of the vehicle in accordance with an embodiment of the present subject matter.
[00019] Figure 10 shows the top view of the proposed gear shift assembly in accordance with an embodiment of the present subject matter.
[00020] Fig. 11 shows a sectional view of a crankcase in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION
[00021] The transmission is one of the essential and important components of a vehicle. The motive force produced by the prime mover, for example the engine, is transferred to the driving wheels of the vehicle through the transmission system. Typically, the transmission system is a bulky component of the power train unit of the vehicle.
[00022] Transmission system of a vehicle, may be classified as automatic, semi-automatic, automated manual transmission (AMT) or manual, based on how gear shifting is accomplished.
[00023] In case of automatic transmission there is no manual intervention for shifting the gears and the power is typically transmitted through a pulley and belt system. The gear shifting is fully automated and changed by a gear actuating motor by the vehicle control unit (VCU) on the basis of certain parameters. In semi-automatic transmission the gear shifting is also done by a gear actuating motor, but the rider instructs the VCU by set of inputs, that when to change the gear by means of the gear actuating motor. In case of AMT, gears are also changed automatically; however, it does not utilize the belt and pulley mechanism rather the power is transmitted through conventional gear system.
[00024] The transmission system of a typical two-wheeler engine of a manual gear shifting type vehicle includes a clutch system and a gearbox. The clutch system comprises of the clutch component and a clutch actuating mechanism. The gearbox comprises of plurality of gear pairs mounted on plurality of shafts, with a gear selector mechanism placed below (or above) the gear-shaft assembly, that sets the power transmitting gear pair in the gearbox. The power produced needs to be transferred in a controlled manner to wheels which is done by the transmission using specific combinations of gear arrangements. The gear ratio may be changed or selected through a gear shifting mechanism based on vehicle operating conditions.
[00025] The manual gear shifting system involves a clutch actuation & gear change actuation by a rider, while in automatic gear shifting system usually both the actuations are done by automated systems, based on vehicle operating conditions without rider’s intervention.
[00026] Some known arts disclose about automated manual transmission system comprising of a gear shift motor for actuating gears and a clutch actuation motor for actuating the clutch during shifting of gears while the rest of the system remains similar to a conventional manual transmission. The motors are operated based on predetermined control logic which is pre-stored in a processor or vehicle control unit (VCU) of the vehicle.
[00027] Some other known arts disclose about an automatic gear shifting mechanism, where clutch actuation is performed either by a separate actuation motor or by a mechanism within the clutch that comprises of a centrifugal mechanism that responds to engine speed, while the gear actuation is done by an actuator, for example a gear shift motor that drives the motion of a shift drum through gear reduction mechanism.
[00028] The conventional transmission is bulky and requires considerable space in any automotive vehicle, especially in case of two wheeled or three wheeled or small four wheeled vehicle (for example Quadricycle) where vehicle space constraint is a major challenge. With the introduction of automatic gear shifting mechanism, the existing transmission may become bulkier as it requires extra space to install gear shift motor. With compact vehicles where there is a space constraint it may become challenging to accommodate the gear shift motor.
[00029] Generally, in any compact vehicle there is a space constrain especially in a vertical direction of the engine assembly, for example, in a particular type of vehicle layout. Therefore, in order to provide vertical mounting of the gear shift motor, the complete layout of existing vehicle may need to be changed which is a costly and complex.
[00030] Also, in case of two wheeled vehicles the gear shift motor may be visible from outside and can hamper the overall aesthetics of the vehicle. Hence the gear shift motor need to be placed such that the aesthetics of the vehicle is not compromised.
[00031] Also, another challenge is an external impact on the gear shift motor such as stone hitting or environmental impact which may damage the gear shift motor completely because of the exposed parts of the gear shift motor. Therefore, the gear shift motor needs to be packaged such that there is minimum external impact on gear shift motor and it remains protected.
[00032] The gear shift motor output may not be used as it is and needs to be reduced to a suitable level using a reduction mechanism. The reduction mechanism comprises a number of gear pairs which reduces output torque and speed. The number of reduction gear pairs may vary based on requirement such as output torque, speed required for actuating the clutch and gears. There is a transmission loss with use of such a reduction mechanism. As per known arts, the motor output shaft and the gear shift mechanism are placed at a distance from each other which requires longer and complex mechanisms to transmit the power of motor to the gear shift mechanism. Due to this, there is a higher transmission loss, also the cost of the system is higher due to complex mechanism. Hence it is desirable that the gear shift motor and gear shift mechanism are placed close to each other such that there is minimum transmission loss.
[00033] Moreover, the gear shift motor should be placed such that the easy accessibility is possible during fault detection or serviceability, without disassembling any major part of the power train of the vehicle.
[00034] Moreover, the placement of the gear shift motor should be such that the drive assembly which connects the gear shift motor and a shift drum of a vehicle, is placed submerged in lubrication oil, so that requirements of extra parts such as bearings can be avoided and thus weight and cost of the engine assembly can be considerably reduced.
[00035] Hence, there is a need of addressing the above circumstances and problems of the known arts.
[00036] The present subject matter has been devised in view of the above circumstances as well as solving other problems of the known art.
[00037] The present subject matter discloses an improved power train for a vehicle. The power train includes an internal combustion engine, and a transmission assembly. The transmission assembly includes a clutch assembly and a gear box. The gear box includes a gear shifting assembly and a multistage gear reduction assembly.
[00038] As per an aspect of the present subject matter the gear shifting assembly includes a shift drum, an electric machine, for example, a gear shift motor, and an electric machine gear assembly. The shift drum is operatively coupled to the electric machine through the multistage gear reduction assembly.
[00039] As per another aspect a horizontal first plane splits the crankcase into a top region and a bottom region. The bottom region of the crankcase (201) is filled with lubricating oil, and the horizontal first plane substantially passes in proximity of a central axis of the shift drum, the electric machine, and the electric machine gear assembly.
[00040] As per another aspect of the present embodiment, the multistage gear reduction assembly includes an intermediary shaft, the intermediary shaft holds a plurality of drive gears, and a secondary shaft, the secondary shaft holds a plurality of driven gears.. The plurality of drive gears are operably coupled to the plurality of driven gears, and the plurality of driven gears are operably coupled to the shift drum to engage with the electric machine gear assembly.
[00041] As per another aspect of the present subject matter, the multistage gear reduction assembly is disposed substantially equally on both top and bottom side of the horizontal first plane. An oil pump assembly is substantially disposed below the horizontal first plane.
[00042] As per another aspect of the present embodiment, the plurality of drive gears is freely rotatably installed on the intermediary shaft. The plurality of driven gears are freely rotatably installed on the secondary shaft.
[00043] As per another aspect of the present embodiment, the electric machine gear assembly are installed on a bush, wherein the bush is installed on a tertiary shaft.
[00044] As per an alternate embodiment, the electric machine being a gear shift motor.
[00045] As per another aspect of the present embodiment, the electric machine includes an output shaft. The output shaft is configured to have plurality of external splines, the external splines being meshed with the electric machine gear assembly.
[00046] As per an aspect, the electric machine gear assembly includes at least a first gear, at least a second gear, and at least a third gear.
[00047] As per another aspect of the present embodiment, the third gear is meshed with the drum shift. The first gear is meshed with the plurality of external splines on the output shaft. And the second gear connects the first gear and the third gear.
[00048] As per an alternate embodiment, the transmission assembly being enclosed in a crankcase. The crankcase includes a crankcase LH extending leftwards in the internal combustion engine width direction and a crankcase RH extending rightwards in the internal combustion engine width direction. The crankcase LH and the crankcase RH comprises of a top portion, a bottom portion and a plurality of side portions. The plurality of side portions are substantially vertical and being configured to extend between the top and the bottom portion. The one of the crankcase side is provided with a recess portion being configured to receive the electric machine.
[00049] The plurality of side portions includes a crankcase LH side portion and a crankcase RH side portion. The electric machine is received in at least the crankcase LH side portion or at least crankcase RH side portion or both.
[00050] The crankcase RH extends in rightward direction. The crankcase LH extends in leftward direction of the internal combustion engine.
[00051] As per another embodiment, the crankcase LH being covered by housing to make powertrain leak proof and enable effective lubrication.
[00052] As per an aspect of the present embodiment, the shift drum is disposed ahead of the electric machine when viewed from top of the internal combustion engine.
[00053] As per an aspect of the present embodiment, the gear shift assembly is disposed in proximity of an oil sump.
[00054] As per another aspect of the present embodiment, the distance between a central axis of the electric machine and a central axis of the shift drum is a predetermined distance. As per a preferred embodiment, the predetermined distance ranges from 50mm to 70mm.
[00055] As per another aspect of the present embodiment, the distance between an outer edge of the electric machine and an outer edge of the shift drum is a predetermined distance. As per a preferred embodiment, the predetermined distance ranges from 50mm to 70mm.
[00056] As per a preferred embodiment, the diameter of the electric machine ranges from 45mm to 60mm and the diameter of the shift drum ranges from 35mm to 55mm.
[00057] As per another aspect of the present embodiment, the driven gear being detachably coupled to the shift drum using attachment means, the attachment means includes one or more bolts.
[00058] As per an embodiment, the electric machine is attached to a crankcase RH side portion or the crankcase LH side portion or both using attachment means.
[00059] As per an embodiment, the transmission assembly includes one or more centrifugal clutch for automatic clutch actuation based on engine operating speed.
[00060] As per an alternate embodiment, the present subject matter includes a straddle type two wheeled vehicle comprising a frame assembly and the powertrain.
[00061] As per an alternate embodiment, the present subject matter includes a three wheeled vehicle comprising a chassis frame structure; and a powertrain.
[00062] Exemplary embodiments detailing features regarding the aforesaid and other advantages of the present subject matter will be described hereunder with reference to the accompanying drawings. Various aspects of different embodiments of the present invention will become discernible from the following description set out hereunder. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof. Further, it is to be noted that terms “upper”, “down”, “right”, “left”, “front”, “forward”, “rearward”, “downward”, “upward”, “top”, “bottom”, “exterior”, “interior” and like terms are used herein based on the illustrated state or in a standing state of the two wheeled vehicles with a driver riding thereon. Furthermore, arrows wherever provided in the top right corner of figure(s) in the drawings depicts direction with respect to the vehicle, wherein an arrow F denotes front direction, an arrow R indicates rear direction, an arrow Up denotes upward direction, an arrow Dw denotes downward direction, an arrow RH denotes right side, and an arrow LH denotes left side. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
[00063] Fig. 1 illustrates a side view of a vehicle 100 in accordance with an embodiment of the present invention. The vehicle 100 includes a frame assembly (not shown) to support different parts of the vehicle 100. In an upper portion of the frame assembly (not shown), a handlebar assembly 115 is rotatably integrally connected to the steering shaft (not shown). The handlebar assembly 115 is used to steer the vehicle 100 and is connected to a front wheel 185 through the steering shaft (not shown) and a front fork assembly (195). An upper portion of the front wheel 185 is covered by a front fender 190 which prevents mud and water from getting deflected towards the steering shaft (not shown). Further, the front fork assembly (195 ) is supported on the front fender 190 by means of a brace fender (not shown).
[00064] In a front portion of the frame assembly (not shown) a fuel tank assembly 120 is arranged immediately behind the handlebar assembly 115 and is disposed over a first power source, for example an internal combustion engine 180. A seat assembly 125 is placed behind the fuel tank assembly 120. The seat assembly 125 includes a front rider seating portion and a pillion rider seating portion. The pillion rider seating portion is placed on the rear part of the frame assembly (not shown), where the rear part of the frame assembly (not shown) is covered by the tail cover assembly (not labeled).
[00065] For the safety of the rider and in conformance with the traffic rules, a headlamp assembly 105 that includes a headlamp 110 and front indicator lights 140a are provided in the front portion of the vehicle 100. On the rear portion of the two wheeled vehicle 100 a tail lamp (not labeled) and rear indicator light 140b are provided on the rear portion of the tail cover assembly (not shown). Above the tail cover assembly 130 and behind the seat assembly 125 a pillion handle 135 is provided for the pillion rider to grab.
[00066] Suspension systems are provided for comfortable steering of the two wheeled vehicle 100 on the road. A front suspension assembly 195 serves as rigidity component for the front portion of the vehicle 100 just like the frame assembly (not shown). The front suspension assembly 195 clamped to the head tube (not labelled) through an upper bracket (not labelled ) and a lower bracket (not labelled) is capable of being moved to the left and right. Further, a rear suspension system 160, which is a hydraulic damped arrangement, is connected to the frame assembly (not shown). The rear suspension system 160 comprises of at least one rear suspension 160 preferably disposed centrally in the longitudinal mid plane of the vehicle 100. However, in a vehicle 100 with two rear suspensions, the same may be disposed on the left side and the right side respectively of the vehicle 100.
[00067] The first power source, for example the internal combustion engine 180 is mounted to a front lower portion of the frame assembly (not shown) by means of an engine mounting bracket (not shown). The internal combustion engine 180 is partially covered on the lower side of the internal combustion engine 180 by an engine cover 175. The internal combustion engine 180 is equipped with an exhaust system that includes an exhaust pipe connected to the internal combustion engine 180 and a muffler assembly 155 connected to the exhaust pipe. The muffler assembly 155 extends rearwards along the right side of the rear wheel 150.
[00068] Further, a swing arm 200 extending rearwards is swingably connected to a lower rear portion of the vehicle 100. The rear wheel 150 is rotatably supported at a rear end of the swing arm 200. Power from the internal combustion engine 180 is transmitted to the rear wheel 150 through a power drive mechanism, such as a drive chain, so as to drive and rotate the rear wheel 150. A center stand 165 is provided in between the front wheel 185 and the rear wheel 150 for parking the vehicle 100.
[00069] A rear fender 145 for covering an upper side of the rear wheel 150 is mounted to a rear portion of the vehicle 100 to prevent mud and water splashed by the rotating rear wheel 150 from entering the muffler assembly 155, the internal combustion engine 180 and other parts disposed close by. To enhance the overall aesthetics of the vehicle 100 and to prevent undesired foreign particles from entering parts of the vehicle 100, a plurality of rear covers (not labeled) is attached to a rear portion of the frame assembly (not shown).
[00070] Area below the seat assembly 125 and the fuel tank assembly 120 of the vehicle 100 is covered on both sides by a cover frame assembly 170. The cover frame assembly 170 includes the one or more side covers.
[00071] Fig. 2 illustrates a side perspective view of a power train 400 of a vehicle 100, including an internal combustion engine 180, according to an embodiment of the present subject matter. The powertrain 400 encompasses every component that converts an engine’s 180 power into the movement of the vehicle 100. This includes an engine 180, a transmission system, driveshaft, differentials, axles; basically anything from the engine 180 through to the output from the powertrain which is to be transmitted to wheels of the vehicle 100.
[00072] The internal combustion engine 180 includes a cylinder block 202 supported by a crankcase assembly 201 of the internal combustion engine 180. The cylinder block 202 defines a cylinder portion at which a piston can perform reciprocating motion. A cylinder head 203 is mounted to the cylinder block 202 and the cylinder head 203 acts as one end of the cylinder portion. The cylinder block 202 is provided with cooling fins 206 and the cylinder head 203 may be provided with the cooling fins (not shown).
[00073] The internal combustion engine 180 comprises a piston (not shown) performing a reciprocating motion in the cylinder portion due to force imparted to it by the combustion of air-fuel mixture. This reciprocating motion is converted and transferred to a rotary motion of a crankshaft 210 through a connecting rod (not shown). Further, a cylinder head-cover 204 is mounted to the cylinder head 203. The crankcase assembly 201 is made up of left-side crankcase and right-side crankcase. The crankcase assembly 201 rotatably supports the crankshaft 210. Further, an electric machine like a magneto assembly 211 or an integrated starter generator is mounted to the crankshaft 210. The magneto assembly 211 during operation is used to charge a battery (not shown).
[00074] The cylinder head 203 includes an intake port 205 and an exhaust port 208 (shown in Fig. 3) that are provided on a first face and a second face of the cylinder head 203. In the present embodiment, the first face is an upward facing side and the second face is a downward facing side thereof. Further, the cylinder head 203 supports a camshaft assembly (not shown) that is capable of operating intake valve(s) and exhaust valve(s) of the internal combustion engine.
[00075] Fig. 3 illustrates a perspective view of a portion of a power train 400 of a vehicle 100, according to an embodiment of the present subject matter.
[00076] The power train 400 of a vehicle 100 includes a gear oil pump drive connected to the crankshaft 210 and rotates integrally with it. The gear oil pump drive includes a primary driving gear 307. The primary driving gear 307 acts a primary drive and is capable of transferring rotational force or torque to a primary driven gear 308 (shown in Fig. 10 ). The primary driven gear 308 is thus operably connected to the crankshaft 210. The cylinder head 203 comprises a valve train arrangement to control opening and closing of intake and exhaust valves present at the intake port 205 (shown in Fig. 2) and exhaust ports 208 thereby controlling intake of air-fuel mixture and outlet of exhaust gases. The camshaft assembly (not shown) is rotatably mounted to the cylinder head 203 (shown in Fig. 2). A cam chain (not shown) operably connects the crankshaft 210 and camshaft assembly. A driven sprocket of the camshaft assembly is configured to be meshed with the primary driving gear 307 and the driven sprocket (not shown) transfers the rotary motion of the crankshaft 210 to the camshaft assembly.
[00077] Typically, the transmission assembly of the power train 400 includes a spring-loaded multiplate friction clutch assembly 207 fixedly attached to the left-hand portion of the crankshaft 210 using plurality of fastening means. The right-hand side of the crankcase 210 encloses a dry magneto assembly 211. The dry magneto assembly 211 is configured to rotate along with the crankshaft 210 to generate power which recharges the battery (not shown). Further, as per an embodiment, a centrifugal fan (not shown) is disposed in front of the magneto assembly 211 forming part of a cooling system of the internal combustion engine 180 (shown in Fig.2) to cool the internal combustion engine 180. The centrifugal fan (not shown) rotates along with the crankshaft 210 and draws atmospheric air inside and circulates it throughout the interior portions of the shroud (not shown).
[00078] The clutch assembly 207 further includes one or more clutch plates 207a, a clutch hub 207b, and a flywheel (not shown). The clutch assembly 207 is fixedly attached by fastening means to an input shaft (not shown). The clutch assembly 207 ensures that the power transmission from the internal combustion engine 180 is engaged and disengaged to the rear wheel 150 (as shown in Fig. 1) based on rotational speed of the engine.
[00079] During running of the vehicle 100 a large amount of heat is generated inside the internal combustion engine 180. For reducing the impact of the heat on the piston, the cylinder block 202 (shown in Fig. 2) and other engine parts, an oil sump 212 is provided in the crankcase 201 to store lubricating oil and collect the falling lubricating oil during normal operation to be cycled again through an oil drain plug 214. To retain that lubricant during normal operation within the internal combustion engine 180 an oil seal housing is provided to which an oil sealing assembly (not shown) is attached. The oil sealing assembly aids in constant storage of the lubricant oil in at least a bottom portion of the crankcase 201.
[00080] Usually, the oil sump 212 is provided at the bottom-side of the left-hand side of the crankcase 201 for continuous lubrication and cooling of a piston and a plurality of piston cylinder wall and other parts of the internal combustion engine 180.
[00081] Fig. 4a illustrates an isometric view of a conventional motorcycle engine, including a crankcase 201. The crankcase 201 includes a crankcase LH 201A and a crankcase RH 201B portion disposed on left and right side of the vehicle 100. The lower portion of the crankcase LH 201A of the conventional motorcycle engine illustrates a gearbox (not labeled) and a gear shift lever (216). The gear shift lever (216) is operably coupled to the shift drum (312) (shown in Fig. 8) which is then connected to a plurality of gears disposed on a plurality of gear box shafts via a mechanical linkage system. The upper portion of the crankcase RH 201B of the conventional motorcycle engine illustrates a clutch cable (215) coming down and getting connected to a clutch assembly (207) on the top.
[00082] Fig. 4b illustrates an isometric view of a power train 400 of a vehicle 100 as per an embodiment of the present subject matter. The present figure illustrates an engine assembly 180 including a crankcase 201. The crankcase 201 includes a crankcase LH 201A and a crankcase RH 201B portion disposed on left and right side of the vehicle 100. The lower portion of the crankcase LH 201A of the present subject matter illustrates an electric machine 300, for example a gear shift motor 300, placed for gear shifting instead of a mechanical connection consisting of gear shift lever 216 (as shown in Fig. 4b). This arrangement makes the present subject matter as automatic or semi-automatic, since the gear shifting now happens either solely by the VCU of the vehicle 100 or as per the input given by the rider to the VCU of the vehicle 100.
[00083] Fig. 5 illustrates an isometric view of a power train 400 of a vehicle 100 as per an embodiment of the present subject matter. The power train 400 of the vehicle 100 can be divided into two separate parts right and left hand side with respect to a vehicle 100, when the power train 400 is divided along a vertical plane AA’. The horizontal plane BB’ schematically separates the crankcase 201 of the power train 400 from the engine 180 of the vehicle 100. The right hand side of the crankcase 201 is herein called as a crankcase RH 201B and the left hand side of the crankcase 201 is herein called as a crankcase LH 201A . The crankcase 201 can be further divided into a top portion, a bottom portion and a plurality of side portion. The pluralities of the side portion are substantially vertical and being configured to extend between the top portion and the bottom. The plurality of side portions includes a first region 300A (shown in Fig. 6) and a second region 300B (shown in Fig. 6). The second region 300B being configured to receive at least a portion of the electric machine 300 in a recess (405) so as to dispose the electric machine (300) in said first region (300A).
[00084] A gear box 217 is disposed substantially above the electric machine 300. The electric machine 300 is further coupled to the shift drum 312 for gear shifting operation by means of the electric machine gear assembly 311. The crankcase LH 201A also illustrates a magneto assembly 211 and a clutch cover 207c enclosing a clutch assembly 207 on the crankcase RH side 201B of the vehicle 100.
[00085] Fig. 6a to Fig. 6b illustrates left and right-side views of the crankcase LH 201A of a vehicle 100 as per an embodiment of the present subject matter.
[00086] The crankcase 201 includes a crankcase LH 201A extending leftwardly in the internal combustion engine 180 width direction and a crankcase RH 201B extending rightwardly in the internal combustion engine 180 width direction. The plurality of the side portions includes a crankcase LH 201A side portion and a crankcase RH 201B side portion.
[00087] The electric machine 300 is received in at least the crankcase LH 201A side portion or at least crankcase RH 201B side portion or both.
[00088] As per an embodiment, the lower most portion of the crankcase LH 201A includes a first region 300A and a second region 300B. A recess portion 405 provided centrally in the second region 300B is configured to receive a at least a front portion of the electric machine 300. The first region 300A receives at least a side and rear portion of the electric machine 300 by being mounted on the recess 405 portion present in the second region 300B. The electric machine 300 is disposed slightly below and approximately adjacent to the gear box 217 of the power train 400. The electric machine 300 is affixed to the crankcase 201 by means of a plurality of bolts 302 on gear shift motor mounting provision 301 present at least on a portion of the crankcase 201. The electric machine is disposed above and in proximity of the oil sump 212.
[00089] Moreover, the gear shift motor 300 or the electric machine 300 is placed substantially the lower most region of the power train 400, which is visible to the user and easily accessible. Therefore, such layout design of the gear shift motor 300 or the electric machine 300 enables easy accessibility possible during fault detection or serviceability, without disassembling any major part of the power train of the vehicle 100.
[00090] As per an alternate embodiment, the electric machine 300 partially overlaps a LH side surface of a crankcase LH 201A and a RH side surface of a RH crankcase 201B when viewed from a rear side view of the internal combustion engine 180.
[00091] Fig. 7 illustrates a gear box 217 of a vehicle 100 along with the electric machine 300, for example a gear shift motor 300, in accordance with an embodiment of the present subject matter. The gear box 217 of the vehicle 100 comprises of a multistage gear reduction assembly 303 and a gear shift assembly 304. The torque and speed of a wheel is controlled by the VCU of the vehicle 100 for shifting gears as per the requirement of the rider by means of the electric machine 300, for example a gear shift motor 300. The multistage gear reduction assembly 303 includes an intermediary shaft 305 and a secondary shaft 306. The intermediary shaft 305 includes a plurality of drive gears 307 and the secondary shaft 306 includes a plurality of driven gears 308. One or more bushes (not shown) are present in between the intermediary shaft 305 and a plurality of drive gears 307 and between the secondary shaft 306 and a plurality of driven gears 308. The gear shift assembly 304 includes the gear shift motor 300 and an electric machine gear assembly 311.The electric machine gear assembly 311 is installed on a bush 403, wherein the bush 403 is installed on a tertiary shaft 404. One of the driven gears 308 is operably detachably coupled to the shift drum 312.
[00092] The secondary shaft (306) has a sprocket ‘S’ at one end. The gears are arranged with their axes aligned to their respective shafts. Some of the gears (also known as dog clutches) are internally splined. These splines perfectly mesh with external splines on their respective shafts. Splines allow these gears to slide sideways while maintaining the same angular speed as the shaft. Others are the freewheeling gears (the speed reduction gears) which can freely spin about their axes but cannot slide sideways along the shaft. All the freewheeling gears adjacent to the dog clutches have recesses in them in which the dog teeth can slide in and lock the two gears.
[00093] The gear shift assembly 304, as the name suggests, assists in shifting or changing of plurality of gears (307, 308) disposed on the intermediary shaft 305 and the secondary shaft 306.
[00094] As per an alternate embodiment, one end of the intermediary shaft 305 or the secondary shaft 306 is supported by a housing (not shown) and another end is supported by a crankcase RH 201B.
[00095] The gear shift motor 300 output may not be used as it is and needs to be reduced to a suitable level using a reduction assembly 303. The reduction assembly 303 reduces output torque and speed. The number of reduction gear pairs may vary based on requirement such as output torque, speed required for actuating the clutch and gears. There is a transmission loss with use of such a reduction mechanism.
[00096] As per the present embodiment, the gear shift motor 300 and the electric machine gear assembly 311 of the gear shift mechanism 304 are placed at in proximity with each other. Resultant to which the power of the gear shift motor 300 can be easily transmitted to the electric machine gear assembly 311of the gear shift mechanism 304. Due to this, there is a lower transmission loss; also, the cost of the system is considerably reduced when compared with the known arts.
[00097] Fig. 8 illustrates a gear shift assembly 304 as per an embodiment of the present subject matter. In the proposed embodiment, instead of a ratchet mechanism which is usually used in manually actuated gear shift assembly 304; an electric machine 300 is connected to the electric machine gear assembly 311 by means of a plurality of external spline 310 present on an output shaft 309. The electric machine gear assembly 311 are mounted over a tertiary shaft 404. The plurality of external splines 310 are operably connected to the electric machine gear assembly 311, which is further connected to a shift drum 312. The power is transmitted via the electric machine 300 to the electric machine gear assembly 311 and then the electric machine gear assembly 311 rotates the shift drum 312 at specific angles in order to change the gears. The rotation of shift drum 312 makes the shifting forks (not shown) slide through the channels over it, which is further connected to the multi stage gear reduction assembly 303 and thus the gear shifting occurs accordingly.
[00098] Fig. 9 illustrates a horizontal cut section view of the crankcase 201 of the vehicle 100 in accordance with an embodiment of the present subject matter. Fig. 10 illustrates a front sectional view of the crankcase 201 of the vehicle 100 in accordance with an embodiment of the present subject matter.
[00099] Both Fig. 9 and Fig. 10 illustrates that the electric machine gear assembly 311 is disposed adjacent to the electric machine 300, which is further placed in proximity of the oil sump 212.
[000100] A horizontal first plane XX’ splits the crankcase 201 into a top region and a bottom region; the bottom region of the crankcase 201 is filled with lubricating oil, and the horizontal first plane XX’ substantially passes in proximity of a central axis of said shift drum 312, the electric machine 300, and the electric machine gear assembly 311. Since the shift drum 312, the electric machine 300, and the electric machine gear assembly 311 are placed along the same horizontal first plane XX’, the proximity of all the three components with each other is ensured. This close proximity further ensures adequate compactness of the engine assembly, as none of the three components, especially the electric machine 300 protrudes out from any of the outermost edges of the side portions of the crankcase 201.
[000101] The multistage gear reduction assembly 303 being disposed substantially equally on both top and bottom side of said horizontal first plane XX’.
[000102] Moreover, since the electric machine gear assembly 311 is in proximity with the oil sump 212, this further aids in lubrication of the electric machine gear assembly 311, as a considerable portion of the electric machine gear assembly 311 is always submerged in the lubricating oil. Resultant to which the electric machine gear assembly 311 does not require any extra component to ensure effective lubrication of the electric machine gear assembly 311. This improves durability by providing continuous lubrications for the components, with less demand for bearings or special lubrication supply. Further this also makes the power train 400 of the vehicle cost effective and lighter in weight.
[000103] As per another aspect, an oil pump assembly 402 is substantially disposed below the horizontal first plane XX’. An oil assembly gear 401 is also disposed above the oil pump assembly 402.
[000104] Fig. 11a to Fig. 11b shows perspective views of the proposed gear shift assembly 303 in accordance with an embodiment of the present subject matter. The electric machine 300 has an output shaft 309 with protruding external splines 310 present on the outward tip of the output shaft 309. The output shaft is further connected to the electric machine gear assembly 311 which is operably coupled to the electric machine 300 to the shift drum 312.
[000105] The shift drum 312 is disposed of ahead of the electric machine 300 when viewed from top of the internal combustion engine 180.
[000106] The electric machine gear assembly 311 includes a plurality of gears, for example a first gear 311a, a second gear 311b, and a third gear 311c connected to each other. The first gear 311a, the second gear 311b, and the third gear 311c are rotatably disposed together on a tertiary shaft 404. The first gear 311a is meshed with the external splines 310 of the output shaft 309. The third gear 311c is meshed with either at least a portion of the shift drum 312 or at least a gear of the plurality of driven gears 308. The second gear 311b connects the first gear 311a and the third gear 311c. The other end of the shift drum 309 includes a gear position sensor 313.
[000107] In an embodiment, the power from the electric machine 300 is transferred from the electric machine 300 via external splines 310 to the first gear 311a positioned on the tertiary shaft 404. The first gear 311a further transmits the power to the second gear 311b, positioned on the same shaft. The power is further transmitted to the third gear 311c via the second gear 311b. The third gear 311c finally transmits the power to the shift drum 312 of the power train.
[000108] Since the space taken for the layout of the electric machine 300 is within the boundaries of the crankcase 201, i.e., without any unusual protrusion, such configuration facilitates use of same housing components for both Manual & automatic transmission gearbox. As per an alternate embodiment, the gear shift lever 216 can also be accommodated with the electric machine 300.
[000109] The distance between a central axis of the electric machine 300 and a central axis of said shift drum 312 being a predetermined distance d, wherein as per a preferred embodiment said predetermined distance d ranges from 50mm to 70mm.
[000110] The distance between an outer edge of the electric machine 300 and an outer edge of the shift drum 312 being a predetermined distance d1. As per a preferred embodiment, the predetermined distance d1 ranges from 50mm to 70mm.The diameter of said electric machine 300 ranges from 45mm to 60mm.The diameter of the shift drum 312 ranges from 35mm to 55mm.
[000111] As per an alternate embodiment, the transmission assembly includes one or more centrifugal clutch assembly 207 based on engine speed, the centrifugal clutch being actuated by one or more clutch actuation motor.
[000112] As per an alternate embodiment, the crankcase RH 201B extends in rightward direction, and a crankcase LH 201A extends in leftward direction of the internal combustion engine 180. The crankcase LH 201A being covered by a housing cover to make powertrain 400 leak proof and enables effective lubrication.
[000113] As per an alternate embodiment, the present subject matter includes a straddle type two wheeled vehicle comprising a frame assembly and the powertrain.
[000114] As per an alternate embodiment, the gear box 217 being disposed integrally inside crankcase 201 on the power train 400 so as to configure the multistage gear reduction assembly 303 and the gear shit assembly 304 inside the lubricated region of the crankcase 201.
[000115] As per an alternate embodiment, the present subject matter includes a three wheeled vehicle comprising a chassis frame structure; and a powertrain 400.
[000116] Many modifications and variations of the present subject matter are possible in the light of above disclosure. Therefore, within the scope of claims of the present subject matter, the present disclosure may be practiced other than as specifically described.
LIST OF REFERENCE NUMERAL
100 – Vehicle
105- Head lamp assembly
110- Head lamp
115- Handle bar assembly
120- Fuel tank assembly
125- Seat assembly
130- Tail cover assembly
135- Pillion handle
140a- Front indicator light
140b- Rear Indicator light
145- Rear fender
150- Rear wheel
155- Muffler assembly
160- Rear suspension system
165- Center stand
170- Cover frame assembly
175- Engine cover
180- Internal combustion engine
180A- Engine LH side
180B- Engine RH side
185- Front wheel
190- Front fender
195- Front suspension assembly
200- Swing arm
201- Crank case
201A- Crank case LH
201B- Crank case RH
202- Cylinder block
203- Cylinder head
204- Cylinder head cover
205- Intake port
206- Cooling fins
207- Clutch assembly
207a- Clutch plates
207b- Clutch hub
207c- Clutch cover
208- Exhaust port
210- Crankshaft
211- Magneto assembly
212- Oil sump
214- Oil drain plug
215- Clutch cable
216- Gear shift lever
217- Gear box
218- Starter motor
AA’- Vertical line
BB’- Horizontal line
300- Gear shift motor or electric machine
300A- First region
300B- Second region
301- Gear shift motor mounting provision
302- Bolts
303- Multistage gear reduction assembly
304- Gear shifting assembly
305- Intermediary shaft
306- Secondary shaft
307- Drive gear
308- Driven gear
309- Output shaft
310- External spline
311- Electric machine gear assembly
311a- First gear
311b- Second gear
311c- Third gear
312- Shift drum
313- Gear position sensor
400- Power train
401- Oil assembly gears
402- Oil pump assembly
403- Bush
404- Tertiary shaft
405- Recess portion