WO2021152610A1

WO2021152610A1 - Powertrain assembly

Info

Publication number: WO2021152610A1
Application number: PCT/IN2021/050054
Authority: WO
Inventors: Meibalan Mugilan; Rawat ANKIT; Subramoniam Chithambaram
Original assignee: Tvs Motor Company Limited
Priority date: 2020-02-01
Filing date: 2021-01-21
Publication date: 2021-08-05
Also published as: MX2022008180A; CN114945489A

Abstract

The present invention relates to a powertrain assembly (PA) comprising of a prime mover (101) which is supported on a primary housing (201), primary housing (201) enclosing a transmission system. The transmission system includes a drive shaft assembly (DSA) operatively connected to the driven shaft assembly (DSRA)through transmission means (206), a cover member (202), cover member (202) is detachably attached to the primary housing (201), and a secondary housing (203),secondary housing (203) enclosing a gear reduction system. Thus, the present subject matter facilitates the working of low torque prime mover (101) using two stage reduction transmission system wherein primary transmission is chain drive and secondary transmission is gear drive, thereby slackness in the chain drive is reduced which increases the efficiency of powertrain assembly (PA). Moreover, the slackness in the chain drive due to prolonged usage is compensated by use of guiding and tensioner assembly (GTA).

Description

POWERTRAIN ASSEMBLY

TECHNICAL FIELD

[0001] The present subject matter relates to the vehicle. More particularly, the present subject matter relates to powertrain assembly for an electric vehicle.

BACKGROUND

[0002] Over the past few years, the investment and market viability of the electrical vehicle are growing in a wide range because of high costs of fossil based fuel and at the same time pressing need to be environment-friendly leading to alternative means of transportation. The alternative means includes electric vehicles, where these vehicle uses motor as the prime mover. The electric vehicle is attractive in that the power unit in the form of a rechargeable battery pack is environmentally clean as it does not pollute the air during its operation and its operation is silent. Hence preference of users is rapidly shifting towards electrical vehicle for their regular usage. But traction motors must withstand predetermined temperature ranges as well as shock, vibration and abuse hence optimal placement of motors without any compromise in space for luggage compartment or battery storage compartment and at the same time ensuring required torque and speed is always a challenge for automobile players.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.

[0004] Fig. 1 illustrates a left side view of the powertrain assembly (PA), as per preferred embodiment of the present invention.

[0005] Fig. 2 illustrates a sectional top view of a powertrain assembly (PA) across A-A’ axis where few parts are omitted from the figure as per preferred embodiment of the present subject matter. [0006] Fig. 3 illustrates a left side view of the powertrain assembly (PA) where few parts are omitted from the figure, as per preferred embodiment of the present invention where few parts are omitted.

[0007] Fig. 4a illustrates the side view of a drive train oscillation reduction device (213) and top section view of the drive train oscillation reduction device (213) across B-B’ axis as per preferred embodiment of the present subject matter. [0008] Fig. 4b illustrates an exploded view of a powertrain assembly (PA) showing drive train oscillation reduction device (213) as per preferred embodiment of the present subject matter.

DETAILED DESCRIPTION

[0009] Various features and embodiments of the present invention here will be discernible from the following further description thereof, set out hereunder. It is contemplated that the concepts of the present invention may be applied to any type of vehicle employing the similar powertrain within the spirit and scope of this invention. The detailed explanation of the constitution of parts other than the present subject matter which constitutes an essential part has been omitted at suitable places. The word “prime mover” and “electric motor” used interchangeably throughout the specification.

[00010] The high costs of fossil-based fuel & its impact on pollution is leading to research & development of alternative means of transportation. Moreover, original equipment manufacturer (OEMs) and customers are being driven down a path to reduce carbon dioxide emissions by electrifying the drivetrain which has the capability to propel vehicles while enabling space inside the vehicles to allow large enough battery packs to give adequate range. As in automobiles torque and speed are important parameters, these can vary as per different segment of the vehicle; likewise, the electric vehicles are designed by keeping these two parameters in mind. It is always a challenge for the automobile manufactures to have appropriate balance between both torque and speed, so in order to achieve different speed at varying loads similarly different torque at different loads requires optimal transmission ratios / system. Power generated from the electric motor when transmitted directly to drive wheel will lead to inappropriate torque since direct drive results in uncontrolled speed or sub-optimal speed and undesirable operating conditions thereby failing to achieve best performance i.e. torque and rpm (revolutions per minute). It is known that the electric vehicles use in-wheel hub motor which is one of the promising technologies in automotive electrification. Typically, in-wheel hub motor drive type configuration are relatively is a rapidly developing solution along with variable speed drive but at the same time the inherent disadvantage of in-wheel motors is limited torque delivery to drive wheel independently. Thus, in order to get desired or higher torque, the size of in-wheel motor should be increased. Further, the increased size of in-wheel hub motor leads to increase in the size of the wheel assembly. So, there is trade off by moving the drivetrain mass from the sprung to the unsprung mass as well as space availability. This increased unsprung mass is often challenged with increased unsprung mass/sprung mass ratio which can result in dangerous, uncomfortable vehicles. Increasing wheel size brings in additional drawbacks in terms of packaging, inertia losses, seating height etc. Typically, in vehicles like two wheelers (like scooters) or three wheelers the wheel assembly size is smaller and any increase in the wheel assembly size or addition of component leads to layout constraints in designing a compact low weight power train. Further, wheel rim may bend due to high inertia of electric motor and which can also cause the water to get inside the motor easily. This ingression of water inside motor may cause the motor short circuit. Moreover, it is difficult to provide motor cooling as it is disposed inside wheel hub, which tends to further decrease the efficiency of the motor because of heat and there by decrease the electric vehicle range, as more power or energy can get wasted in heat energy from the battery or energy source.

[00011] Therefore, for best vehicle performance and optimal operating conditions, to transmit power from the power unit to drive wheel of the vehicle a transmission system or gear box is typically provided. However, a trade-off between torque requirement and range of the vehicle is difficult since at higher torque requirements the range of the vehicle drops. Thus, to assure an effective torque developed by drive wheel and the force applied to road surface special attention has been given to the electric drive comprising of independent electric motor mounted on the frame assembly. Typically, independent electric motor is connected to the drive wheel through the endless transmission the tension in the endless transmission means like chain is a very essential parameter that determines transmission system performance. A transmission system having chain connecting motor shaft to the drive wheel is typically subject to elongation of its length owing to wear and tear of the chain links; which in turn results in slackness of the chain; causes loss in the efficiency of the transmission and thus loss in performance of powertrain assembly as well as poor durability. Further, the reduction devices are used in the vehicle to increase the amount of torque per revolution of a shaft which increases the torque but often challenged with increased stress in the chain which connects the gear reduction output from electric motor to the drive wheels. Furthermore, due to tension and slackness whipping of chain occurs. This results in rough performance of the powertrain assembly accompanied by noise and vibration resembling a rattle which increases with r.p.m. (revolution per minute) of the electric motor. Thus, affecting the NVH, durability, reliability & transmission efficient of the chain. Hence, these conventional powertrain assemblies known in the art are complex, functionally inferior and economically disadvantageous.

[00012] I Independent motors supported on the frame assembly have the ability to produce high torque over a range of speeds. Therefore, high capacity of the electric motor is preferably adapted which results in more weight and cost. Further, higher capacity electric motors draw more power from the batteries. Thus, to increase the range of the electric vehicle high watt-hour batteries need to be packaged within the electric vehicle. Thus, packaging of a high capacity motor and high watt-hour batteries adversely affects the vehicle layout in terms of aspects like adequate foot space or luggage space or utility space, frame design and also involves custom design of frame assembly to support the high capacity electric motor and high watt-hour batteries as well as its location/mountings. So, an electric drive assembly should be implementable with minimal changes in an existing layout architecture of a conventional vehicle and with minimum modification of frame component to support the electric motor.

[00013] Further, drivetrain oscillations in electric vehicle are more as compare to the IC engine powered vehicles. The drivetrain oscillation is a phenomenon of fluctuating vehicle speed caused by torsional vibrations in the vehicle powertrain i.e. initial response or jerk that arises due to high rate of change of driveline torque. In other words, the acceleration jerks of a vehicle propelled by an electric motor, more particularly, jerks felt in acceleration phase from a steady state or after a deceleration phase, requires complex mechanism to reduce the drivetrain oscillations.

[00014] it become more challenging to dampen the high torque oscillation in electric vehicles having a clutch, as clutch will not permit the drive wheel to drive the electric motor during deceleration hence there will be no regeneration during deceleration or regenerative braking.

[00015] I In light of increasing fossil based fuel prices there is need to develop the powertrain assembly that can help to address above issues and which is affordable and within the means of the masses. Thus, a powertrain assembly for a vehicle with at least one electric power unit is proposed in the present subject matter in order to alleviate one or more drawbacks highlighted above & other problems in known art.

[00016] Therefore, it is an aspect of the present invention to provide a powertrain for an electric vehicle having low cost, high transmission efficiency, high conversion efficiency, low cost, good control throughout the entire speed range, no adverse drivetrain jerks or oscillations, good durability, compact layout & flexible architecture to enable change of powertrain platform without the use of clutches to provide energy regeneration.

[00017] It is another aspect of the present invention to provide a powertrain assembly having two stage reduction to provide optimum torque using low torque motor.

[00018] It is yet another aspect of the present invention to provide a powertrain assembly which reduces the drivetrain oscillations. [00019] It is an aspect of the present invention to provide a powertrain assembly with higher rated life.

[00020] The present subject matter relates to a two stage reduction powertrain assembly. The powertrain assembly comprising of a prime mover which is supported on a primary housing, said primary housing enclosing a transmission system. The transmission system includes a drive shaft assembly operatively connected to the driven shaft assembly through transmission means, a cover member, said cover member is detachably attached to the primary housing, and a secondary housing, said secondary housing enclosing a gear reduction system. The transmission means includes chain transmission. Further, the gear reduction system includes a driving gear installed on the driven shaft and a driven gear installed on a wheel shaft. The wheel shaft is parallel and alongside the driven shaft such that said driven gear is engaged with said driving gear. In other words, the two-stage reduction includes primary stage as chain transmission and secondary stage includes gear stage reduction. Further, for primary stage i.e. chain transmission a guiding and tensioner assembly is provided. The guiding and tensioner assembly is mounted between drive shaft assembly and driven shaft assembly. The guiding and tensioner assembly includes a tensioner, and at least two guide members. The tensioner is mounted on the primary housing using at least two bolts. The tensioner is mounted on the top surface of the primary housing.

[00021] Further, the details as well as other features and advantages of this invention are set forth in the remainder of the specification and are shown in the accompanying drawings. Furthermore, the word “Transmission means” and “chain” is used interchangeably throughout the specification [00022] Figure 1 illustrates the side view of powertrain assembly (PA) as per preferred embodiment of the present invention. For example, and by no way limiting the scope of the subject matter. The present invention has a frame assembly (FA) similar to a two wheeler, three wheeler or four wheeler frame known in the art. The powertrain assembly (PA) is pivotally connected to the frame assembly (FA). The present invention can have steering system (not shown) and a seat assembly (not shown). The powertrain assembly (PA) includes a prime mover (101), as per preferred embodiment i.e. electric motor (101) is operatively connected to the drive wheel (100). A braking system (103) is attached to drive wheel (100). In alternative embodiment brake system (103) can be inbuilt in drive wheel (100). As per one embodiment vehicle may have a centre stand (102), used especially when the operator is not on the vehicle. The centre stand (102) is operatively connected to at least portion of the powertrain assembly (PA). A cushioning means (not shown) is used to dampen the road shocks, wherein said cushioning means (not shown) one end is connected to the cushion member mount structure (104).

[00023] Figure 2 illustrates a sectional top view of a powertrain assembly (PA) across A-A’ axis as per preferred embodiment of the present subject matter. For example, and by no way limiting the scope of the subject matter, a prime mover (101) is supported on a primary housing (201), said primary housing (201) enclosing a transmission system. In present embodiment, the transmission system includes a drive shaft assembly (DSA) operatively connected to the driven shaft assembly (DRSA) through transmission means (206), a cover member (202). The cover member (202) is detachably attached to the primary housing (201). The secondary housing (203) encloses a gear reduction system. Furthermore, a wheel assembly (212) is removably attached to the secondary housing (203) such that secondary housing (203) is sandwiched between the wheel assembly (212) and primary housing (201) when viewed from the rear of the powertrain assembly (PA). Thus, the length of the primary housing (201) and cover member (202) is reduced in the longitudinal direction of the powertrain assembly (PA) which makes the layout compact as well as reduces the weight and cost of the primary housing (201) and cover member (202). The drive shaft assembly (DSA) includes driving sprocket (204), said driving sprocket (204) is installed on a drive shaft (207). The drive shaft (207) includes shaft of the prime mover (101) i.e. electric motor (101). A driven shaft (208) is adapted to have external splines at one of its end to accommodate the driven shaft assembly (DRSA). Further, a driven shaft assembly (DRSA) includes a driven sprocket (205) and a drive train oscillation reduction device (213) both are installed on a driven shaft (208). As per preferred embodiment, transmission means (206) includes a chain. The power from the electric motor (101) drives the driving sprocket (204) of the drive shaft assembly (DSA). The driving sprocket (204) drives the driven sprocket (205) through transmission means (206). Typically, the driven shaft (208) further operatively connected to a wheel shaft (209) through gear reduction system. The gear reduction system includes at least one driving gear (214) installed on the driven shaft (208) and at least one driven gear (215) installed on the wheel shaft (209). The wheel shaft (209) is parallel and alongside the driven shaft (208) such that driving gear (214) is engaged with the driven gear (215). For the driven shaft

(208) both the ends are rotatably supported on the bearings (210) such that one end is rotatably supported on the secondary housing (203) and another end is rotatably supported on the primary housing (201). Further, for the wheel shaft

(209) both the ends are rotatably supported on the bearings (211) such that one end is rotatably supported on the secondary housing (203) and another end is rotatably supported on the primary housing (201). This architecture & layout of the drive & drive shaft system enables a compact layout overcoming all problems cited earlier.

[00024] Figure 3 illustrates a left side view of a powertrain assembly where few parts are omitted from the figure as per preferred embodiment of the present subject matter. The transmission system includes a guiding and tensioner assembly (GTA) is provided to maintain optimum tension and support throughout the operating life of the transmission means (206). The guiding and tensioner assembly (GTA) comprising of at least two guide member (302a, 302b) and at least one tensioner (301). The guide members (302a, 302b) is mounted on the slack side and the tensioned side of the transmission means (206) respectively. The primary transmission here is the silent chain transmission, which rotates in the clockwise direction during the forward propulsion of the vehicle. Due to clockwise rotation of the transmission means (206), the slack side comes on the upper side of the transmission means (206) and thereby enables reduction in the transmission torque jump during sudden change in speed of the vehicle. Such a counterintuitive configuration of direction of rotation for torque in conjunction with the architecture of DSA & DRSA together enables a compact layout while overcoming the technical drawbacks cited earlier. Further; the tensioner (301) is mounted on the primary housing (201) using at least two bolts (301a). as per preferred embodiment the tensioner (301) is mounted on the top surface of the primary housing (201). There is normally a housing (not shown) of tensioner (301) which encloses a plunger (not shown). The positive bias force on the plunger (not shown) pushes on the guide member (302a) to maintain optimum tension. The tensioner (301) is mounted on the top of the primary housing (201) with the plunger (not shown) projected inside the primary housing (201). The guide member (302a) and tensioner (301) guide the slack side of the transmission means (206) and apply the pressure coming through the tensioner plunger (not shown) in the downward direction. Further, the guide members (302a, 302b) is configured to have a top land part (not shown). The top land part (not shown) of the guide member (302a, 302b) is in sliding contact with the transmission means (206). These guides the transmission means (206) during its travel & the tensioner member (301) which is configured to exert force on guide member (302a), keeps said top land part (not shown) in contact with the transmission means (206). Thus, with the guiding and tensioner assembly (GTA) configuration, the chain (206) jump is eliminated during the sudden change in the speed of the vehicle. Also, this architecture counters the increase in slackness of transmission means i.e. chain (206) with time. In addition, a guide member (302b) is provided at the bottom side of the transmission means (206). The purpose of providing the guide member (302b) is to avoid the transmission means (206) touching to the primary housing (201) during the vehicle deceleration. As during vehicle deceleration, the driven shaft (208) will become drive shaft and motor shaft (207) will become driven shaft and so the tight and slack side of chain (206) will get interchanged. So, a bottom guide is provided to the chain (206) to avoid its touching to primary housing (201) when it becomes slack side during vehicle deceleration. Further, one-way clutch is not used hence drive wheel (100) is running the prime mover i.e. electric motor (101) during deceleration causing effective regeneration. [00025] Figure 4a illustrates the side view of the drive train oscillation reduction device and top section view of the drive train oscillation reduction device across B-B’ axis as per preferred embodiment of the present subject matter. For example, and by no way limiting the scope of the subject matter, the driven shaft assembly (DRSA) comprises of the drive train oscillation reduction device (213). The drive train oscillation reduction device (213) is primarily formed of a retainer disc (402) and a retainer plate (406). The driven sprocket (205) is disposed between the retainer disc (402) and the retainer plate (406) such that retainer disc (402) is disposed on the prime mover (101) i.e. electric motor (101) side, and the retainer plate (406) is disposed on the transmission side. Further, the retainer disc (402), driven sprocket (205) and retainer plate (406) are fixed together by a plurality of pins (401) passing through plurality of holes provided in each of retainer disc (402), retainer plate (406) and driven sprocket (205). Thereby driven sprocket (205), retainer plate (406) and retainer disc (402) hold together as a single unit. The retainer disc (402) is integrally formed with the insert (407). The insert (407) configured to have a central hole (402c) configured with internal splines corresponding to the external splines on the driven shaft (208). The insert (407) is made up of high-density material as compared to the outer body of retainer disc (402). Thus, selective use of low dense material leads to less weight of powertrain assembly (PA). Further, the plurality of bushes (403) are arranged to maintain optimum gap between the driven sprocket (205) and retainer plate (406). Thus, one end of the bush (403) is protruding in the transmission side in order to maintain optimum gap between driven sprocket (205) and retainer plate (406). While a shim (404a) and spring washer (404b) is provided between the retainer disc (402) and driven sprocket (205) to compress the driven sprocket (205) with retainer plate (406) to prevent the free axial float of driven sprocket (205). This configuration of spring washer (404b) will avoid the rattling noise generation by resisting free axial float of driven sprocket (205).

[00026] Figure 4b illustrates an exploded view of a powertrain assembly showing drive train oscillation reduction device (213) as per preferred embodiment of the present subject matter. For example, and by no way limiting the scope of the subject matter, the plurality of opening (402b, 406b, 205b) in each of retainer disc (402), retainer plate (406), driven sprocket (205) are preferably four in numbers and are circumferentially equally spaced from each other. However, the driven sprocket (205) is configured to have plurality of openings or cavities (205b) of predetermined shape. The predetermined shape is like elongated holes. The elongated openings (205b) accommodate the plurality of bushes (403). Typically, each of retainer disc (402), driven sprocket (205) and retainer plate (406) is configured to have central hole (402c, 205c, 406c) respectively. The central hole (402c, 205c, 406c) is opened axially to accommodate driven shaft (208). Furthermore, the driven sprocket (205) provided with a plurality of driven sprocket windows (205a) in the circumferential direction. These driven sprocket windows (205a) are preferably four in numbers and are circumferentially equally spaced from each other. The plurality of driven sprocket openings or windows (205a) are substantially circumferentially long to accommodate the spring (405). The plurality of driven sprocket windows (205a) are configured to have predetermined shape.

[00027] The plurality of driven sprocket windows (205a) are substantially circumferentially long to accommodate the spring (405) which is disposed such that it is partially protruding from both the sides in axial direction of the driven sprocket (205). Thus, to accommodate the partially protruding portion of spring (405) on both the sides of driven sprocket (205), each of retainer disc (402) and retainer plate (406) is formed of corresponding windows (402a, 406a). Typically, the springs (405) are provided with the axial float between the retainer disc (402) and retainer plate (406) to prevent constraint on radial squeezing during working. Thus during sudden acceleration and deceleration, the plurality of bush (403) in each opening (205b) of driven sprocket allow predetermined radial movement of the driven sprocket (205) between the retainer plate (406) and retainer disc (402) thus causing compression of the spring (405) while reducing the jerk. Further, the direction of compression of spring (405) in acceleration will be opposite to the direction of compression of spring (405) in deceleration. [00028] Therefore, the present invention achieves enhanced transmission efficiency and considerably increases the range of electric vehicle. In other word, the present subject matter facilitates the working of low torque electric motor using two stage reduction transmission system wherein primary transmission is chain drive and secondary transmission is gear drive, thereby slackness in the chain drive is reduced which increases the efficiency of powertrain assembly. Further the size of the primary housing and cover member is reduced in the longitudinal direction as the secondary transmission i.e. gear transmission is provided on the other end i.e. in the lateral direction of the vehicle operatively connected to wheel assembly and primary housing. Additionally, present architecture & layout of the transmission system & powertrain assembly reduces the weight and cost. Furthermore because of low torque prime mover with two stage reduction increases the range of the electric vehicle as less current is drawn by the low torque prime mover while at the same time delivering optimum torque. Moreover, the slackness in the chain drive due to prolonged usage is compensated by implementation of guiding and tensioner assembly. Furthermore, the drive oscillations during sudden acceleration and deceleration are eliminated by using simple and inexpensive drive oscillation reduction device the two-stage reduction transmission system configured to have guiding and tensioner assembly and drive oscillation reduction device enhances the overall performance of the electric vehicle.

[00029] While the present invention has been shown and described with reference to the foregoing preferred embodiments, it will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention.

List of references

DSA Drive shaft assembly

DSRA Driven shaft assembly

Guiding and tensioner assembly Drive wheel/ Rear wheel Prime mover/Electric motor Center stand Brake

Cushion member mount structure

Primary housing

Cover member

Secondary housing

Driving sprocket

Driven sprocket

Plurality of window in driven sprocket

Plurality of openings in driven sprocket

Centre hole in driven sprocket Transmission means or Chain Drive shaft Driven shaft Wheel shaft

Plurality of bearings to support driven shaft Plurality of bearings to support wheel shaft Wheel assembly

Drive train oscillation reduction device Driving gear Driven gear

Tensioner 301a At least two bolts

302a Top guide member 302b Bottom guide member 401 Plurality of pins 402 Retainer disc

402a Plurality of window in retainer disc 402b Plurality of openings in retainer disc 402c Centre hole in retainer disc 403 Bush 404a Shim

404b Spring Washer

405 Spring

406 Retainer plate 406a Plurality of window in retainer plate 406b Plurality of openings in retainer plate

406c Centre hole in retainer plate

407 Insert

Claims

We Claim:

1. A powertrain assembly (PA), the powertrain assembly (PA) architecture comprising of: a prime mover (101); a primary housing (201), said primary housing (201) is supporting the prime mover (101); a transmission system, said transmission system is enclosed in the primary housing (201), wherein said transmission system includes a drive shaft assembly (DSA), said drive shaft assembly

(DSA) is operatively connected to a driven shaft assembly (DRSA) through a transmission means (206); a cover member (202), said cover member (202) is detachably attached to the primary housing (201); and a secondary housing (203), said secondary housing (203) enclosing a gear reduction system.

2. The powertrain assembly (PA) as claimed in claim 1, wherein said powertrain assembly (PA) is pivotally connected to the frame assembly (FA) of an electric vehicle.

3. The powertrain assembly (PA) as claimed in claim 1, wherein said secondary housing (203) is sandwiched between a wheel assembly (212) and the primary housing (201) when viewed from the rear of the powertrain assembly (PA).

4. The powertrain assembly (PA) as claimed in claim 1, wherein said drive shaft assembly (DSA) includes a driving sprocket (204), said driving sprocket (204) is installed on a drive shaft (207).

5. The powertrain assembly (PA) as claimed in claimed in claim 1, wherein said driven shaft assembly (DRSA) includes a driven sprocket (205) installed on a driven shaft (208), and a drive train oscillation reduction device (213).

6. The powertrain assembly (PA) as claimed in claim 1, wherein gear reduction system layout comprises of at least one driving gear (214) installed on the driven shaft (208), at least one driven gear (215) installed on a wheel shaft (209), said wheel shaft (209) is parallel and alongside the driven shaft (208) such that said driven gear (215) is engaged with said driving gear (214).

7. The powertrain assembly (PA) as claimed in claim 5, wherein said driven shaft (208) is rotatably supported by a bearing (210) at one end on the secondary housing (203) and another end is rotatably supported by a bearing (210) on the primary housing (201).

8. The powertrain assembly (PA) as claimed in claim 6, wherein said wheel shaft (209) has one end rotatably supported by a bearing (211) on the secondary housing (203) and another end is rotatably supported by a bearing (211) on the primary housing (201).

9. The powertrain assembly (PA) as claimed in claimed in claim 1, wherein said transmission system comprises a guiding and tensioner assembly (GTA), said guiding and tensioner assembly (GTA) is mounted between drive shaft assembly (DSA) and driven shaft assembly (DRSA).

10. The powertrain assembly (PA) as claimed in claim 9, wherein said guiding and tensioner assembly (GTA) includes at least one tensioner (301), and at least two guide members (302a, 302b), wherein said tensioner (301) is mounted on the primary housing (201) using at least two bolts (301a).

11. The powertrain assembly (PA) as claimed in claim 5, wherein said drive train oscillation reduction device (213) comprising of a retainer disc (402), a retainer plate (406), wherein the driven sprocket (205) is arranged between the retainer disc (402) and the retainer plate (406) such that said retainer disc (402) is arranged on the prime mover (101) side, and the retainer plate (406) is arranged on the transmission side.

12. The powertrain assembly (PA) as claimed in claim 11, wherein said retainer disc (402), driven sprocket (205) and retainer plate (406) are fixed together by a plurality of pins (401) spaced in the rotating direction from each other.

13. The powertrain assembly (PA) as claimed in claim 11, wherein said retainer disc (402) is integrally formed with an insert (407), wherein said insert (407) configured to have a central hole (205c) adapted to have internal splines corresponding to the external splines on the driven shaft (208).

14. The powertrain assembly (PA) as claimed in claim 12, wherein said retainer disc (402) and retainer plate (406) is formed of a central hole (402c, 406c) opened axially and to accommodate the driven shaft (208).

15. The powertrain assembly (PA) as claimed in claim 13, wherein said insert (407) is made up of high-density material as compare to the outer body of retainer disc (402).

16. The powertrain assembly (PA) as claimed in claim 11, wherein said driven sprocket (205), retainer plate (406) and retainer disc (402) is provided with plurality of openings (402b, 205b, 406b) in which a plurality of bushes (403) is disposed.

17. The powertrain assembly (PA) as claimed in claim 16, wherein said plurality of bushes (403) are arranged to maintain optimum gap between the driven sprocket (205) and the retainer plate (406).

18. The powertrain assembly (PA) as claimed in claim 17, wherein one end of the bush (403) is protruding in the transmission side in order to maintain optimum gap between the driven sprocket (205) and the retainer plate (406).

19. The powertrain assembly (PA) as claimed in claim 11, wherein said retainer disc (402) and driven sprocket (205) is configured to have a shim (404a) and spring washer (404b) between them.

20. The powertrain assembly (PA) as claimed in claim 19, wherein said shim (404a) and spring washer (404b) is arrangement is provided between the retainer disc (402) and driven sprocket (205) to compress the driven sprocket (205) with the retainer plate (406) and to prevent the free axial float of the driven sprocket (205).

21. The powertrain assembly (PA) as claimed in claim 11, wherein said driven sprocket (205) configured to have plurality of openings (205b) of predetermined shape to accommodate plurality of bush.

22. The powertrain assembly (PA) as claimed in claim 11, wherein said driven sprocket (205) provided with a plurality of driven sprocket windows (205a), said plurality of driven sprocket windows (205a) is configured to accommodate the spring (405).

23. The powertrain assembly (PA) as claimed in claim 22, wherein said plurality of driven sprocket windows (205a) are arranged in the circumferential direction, said driven sprocket windows (205a) are preferably four in numbers and are circumferentially equally spaced from each other.

24. The powertrain assembly (PA) as claimed in claim 11, wherein said retainer plate (406) and retainer disc (402) is provided with plurality of windows (406a, 402a) corresponding to the plurality of driven sprocket windows (205a) in the driven sprocket (205).