Claims:We Claim:
1. A vehicle configured to have a frame comprising:
an engine (106);
a crankcase (RH, LH) enclosing transmission assembly(TA); said transmission assembly (TA) comprises a drive shaft (301), a driven shaft (302), transmission means (305) and a guiding and tensioning assembly (GTA), said guiding and tensioning assembly(GTA) comprises a guide member assembly (307) and a tensioning member (402),
wherein said guide member assembly (307) configured to have a guide retainer member (805) and top land part (801), said top land part (801) is in slideable contact with the transmission means (305), said tensioning member (402) configured to exert force on the guide member assembly (307) to keep said top land part (801) in contact with the transmission means (305), wherein said guide member assembly (307) pivotally mounted on the crankcase (RH, LH) using fastening means subjected to force applied from the bottom by the tensioning member (402).
2. The vehicle configured to have a frame as claimed in claim 1, wherein said guide retainer member (805) configured to have at least one elongated member (403) extending in lateral axis C – C’ axis of the vehicle (100) provided on at least one side of the guide retainer member (805).
3. The vehicle configured to have a frame as claimed in claim 1, wherein said plunger (404) having end portion which protrudes inside the crankcase LH (204) to exert force on the elongated member (403) and which in turn is configured to move the guide member assembly (307) about the pivot end.
4. The vehicle configured to have a frame as claimed in claim 1, wherein said top land part (801) is snap fitted to the guide retainer member (805).
5. A vehicle configured to have a frame comprising:
an engine (106);
a crankcase (RH, LH) having C- shape wall (902), said crankcase (RH, LH) enclosing transmission assembly (TA); said transmission assembly (TA) comprises a drive shaft (301), a driven shaft (302), transmission means (305) and an integrated guiding and tensioning assembly (IGTA); said integrated guiding and tensioning assembly (IGTA) disposed between the crankcase (RH, LH) bottom half and the slack side of the transmission means (305) such that the integrated guiding and tensioning assembly (IGTA) is configured to be controlled by the C shape wall (902).
6. A vehicle configured to have a frame comprising:
an engine (106);
a crankcase (RH, LH) having C- shape wall (902), said crankcase (RH, LH) enclosing transmission assembly (TA);
said transmission assembly (TA) comprises a drive shaft (301), a driven shaft (302), transmission means (305), an oil pump cover (903) and an integrated guiding and tensioning assembly (IGTA); wherein said integrated guiding and tensioning assembly (IGTA) configured to have a key hole (907) on the bottom half to mount the integrated guiding and tensioning assembly (IGTA) on extended boss (904) of the oil pump cover (903) using mounting means, said key hole (907) accommodate a pre compressed spring (909) to exert a positive bias force on the transmission means (305).
7. The vehicle configured to have a frame as claimed in claim 5 or claim 6, wherein said crankcase LH (901) supports the oil pump cover (903), said oil pump cover (903) configured to have at least one extended boss (904) with mounting holes.
8. The vehicle configured to have a frame as claimed in claim 5, wherein mounting means includes bolt (910), said bolt (910) provided on the base for the pre compressed spring (909).
9. The vehicle configured to have a frame as claimed in claim 5, wherein said spring (909) configured to have a cylindrical pin to avoid lateral movement.
, Description:TECHNICAL FIELD
[0001] The present subject matter relates to transmission assembly. More particularly, the present subject matter relates to guiding and tensioning assembly.

BACKGROUND
[0002] Generally, automobiles are propelled using prime movers which include IC engines. Conventionally, the saddle type vehicles are powered by an internal combustion (IC) engine. An internal combustion (IC) engine comprises a cylinder head, abutting a cylinder block to form a combustion chamber where the burning of air fuel mixture occurs. The forces generated due to combustion of air fuel mixture is transferred to a piston which is capable of reciprocating inside the cylinder block, and this reciprocating motion is transferred to rotary motion of the crankshaft through a connecting rod by the slider crank mechanism. Many saddle type two and three wheeled vehicles such as mopeds, scooters and other automobiles operate on single stage transmission system, wherein a crankshaft of the IC engine is connected to a wheel of the two wheeled vehicle through single stage reduction geartrain.
[0003] As in automobiles torque and speed are important parameters, these can vary as per different segment of the vehicle; likewise, the saddle type wheelers 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 transmission system or gearbox. power generated from the power unit when transmitted directly to rear wheel will lead to in-appropriate torque because direct drive results in uncontrolled speed or sub-optimal speed and operating conditions to achieve best engine performance i.e. torque and rpm (revolutions per minute), Therefore, for best vehicle performance and optimal operating conditions, to transmit power from the power unit to rear wheel of the vehicle, a transmission or gear box is typically provided. However, a trade-off between torque requirement and fuel economy is difficult in a single speed powertrain since at higher torque requirements, the fuel economy drops. is The critical issues involved in the design of the transmission system are to consider improving efficiency, better operability and reduce transmission losses and at the same time retain its attractive features of low cost and easy drivability. The gear box provides various kind of gear ratio as per user requirement. The gearbox is like a machine having controlled application, various gears of different sizes, shafts etc. The gear box has a multiple gear ratio with ability to switch between various speeds. There are many modes of switching like manually or automatically. Automatic transmission system and manual transmission system implemented in such two or three wheeled saddle vehicles such as scooters are known in art. Introducing automatic transmission systems in compact layout and small sized vehicles is difficult in view of the adverse impacts viz. size, layout, cost, weight, number of parts to accommodate the additional transmission components such as clutch, gear trains and one way clutches. Further, the tension in the transmission means like belt or chain is a very essential parameter that determines engine performance. As the chain in any chain drive mechanism 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 engine performance as well as undesirable durability. Hence, a chain tensioner is used which exerts a constant pressure on the transmission means throughout its operation to avoid slackness of the chain. But, due to various factors affecting the chain tensioner, there is a constraint in the movement of a pushrod which exerts constant pressure on the chain. This results in rough performance of the internal combustion (IC) engine accompanied by noise and vibration resembling a rattle which increases with speed of the internal combustion (IC) engine. Further, such vehicles need to have low cost, high efficiency, good control throughout the entire speed range. Hence, a tensioner and guiding system is proposed in the present subject matter in order to alleviate one or more drawbacks highlighted above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] 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.
[0005] Fig. 1 illustrates a left side view of an exemplary vehicle, as per first embodiment of the present invention.
[0006] Fig. 2 illustrates a left side view of engine with wheel drive of the vehicle of Fig.1, as per first embodiment of the present invention.
[0007] Fig. 3 illustrates a left side perspective view of the engine where housing is omitted from the Fig. 2 as per first embodiment of the present invention.
[0008] Fig. 4 illustrates the perspective view of engine and transmission assembly where few parts are omitted, as per first embodiment of the present invention.
[0009] Fig. 5 illustrates an exploded view of the engine and transmission assembly where few parts are omitted as per first embodiment of the present invention.
[00010] Fig. 6 illustrates a cut section of figure 3 taken along plane D-D’ of the engine and transmission assembly of Fig. 3 as per first embodiment of the present invention.
[00011] Fig. 7a illustrates a cross-sectional view of guiding and tensioner assembly when viewed from the rear side of the vehicle across an plane A – A’ of Fig. 6, as per first embodiment of the present invention
[00012] Fig. 7b illustrates a cross-sectional view of at least a portion of guide and tensioner assembly when viewed from the rear side of the vehicle across an plane B – B’ of Fig. 6, as per first embodiment of the present invention.
[00013] Fig. 8 illustrates a perspective view of the guide and tensioner assembly as per first embodiment of the present invention.
[00014] Fig. 9 illustrates an exploded view of the integrated guide and tensioner assembly mounted on oil pump cover as per second embodiment of the present invention.
DETAILED DESCRIPTION
[00015] Various features and embodiments of the present invention here will be discernible from the following further description thereof, set out hereunder. According to an embodiment, the prime mover is an internal combustion (IC) engine, said an internal combustion (IC) engine described here operates in four cycles. Such an internal combustion (IC) engine is installed in a step through type two or three wheeled vehicle. It is contemplated that the concepts of the present invention may be applied to other types of vehicles employing the mechanical rack type chain tensioner within the spirit and scope of this invention. Also the prime mover includes the traction motor and various other propelling means generally known in art. Further "front" and "rear", and "left" and "right" referred to in the ensuing description of the illustrated embodiment refer to front and rear, and left and right directions as seen from a rear portion of the two wheeled vehicle and looking forward. Furthermore, a longitudinal axis Y – Y’ unless otherwise mentioned, refers to a front to rear axis relative to the prime mover i.e. engine, while a lateral axis C – C’ unless otherwise mentioned, refers generally to a side to side, or left to right axis relative to the prime mover i.e. engine.
[00016] However, it is contemplated that the disclosure in the present invention may be applied to power train of any vehicle having without defeating the spirit of the present subject matter. The detailed explanation of the constitution of parts other than the present invention which constitutes an essential part has been omitted at suitable places.
[00017] Generally, in a saddle-wheeled vehicle with a step-through type, a step-through space is provided. The step-though space has a floorboard extending either side in the lateral direction C – C’ and may be used for carrying loads or for the rider to rest feet. In such vehicles, the frame structure starts from the head pipe, and extends downwards to the step-through space and again rises to form a driver seat, crosses a pillion seat and finishes at the rear lamp assembly. The IC engine is of horizontal type that is, a cylinder axis (the axis on which the piston of the IC engine reciprocates) is almost parallel to the central longitudinal axis of the two wheeled vehicle. Typically, the frame assembly acts as a skeleton for the vehicle that supports the vehicle loads.
[00018] The IC engine is functionally connected to a rear wheel of the vehicle such as by a sprocket and chain drive, which provides the forward motion to the vehicle.
[00019] A transmission system for such a wheeled vehicle such as scooter type vehicle comprises a single speed transmission system. Such saddle type vehicles have common requirements of low weight, low cost, high efficiency, good controllability throughout the entire speed range. Typically, the transmission system includes a single transmission stage, a centrifugal clutch, and driven shaft having a sprocket at its end, through which the final drive to a rear wheel is connected. The centrifugal clutch ensures that at low to idle speeds the power transmission from the IC engine is disengaged to the rear wheel. The final drive to the rear wheel of the two wheeled vehicle is usually a positive drive such as sprocket and chain arrangement. Typically, in the two or three wheeled saddle vehicle, a kick-start mechanism or the like is used to crank the IC engine. The kick-start mechanism includes various components such as kick-rod, various gear(s), a return spring, and a ratchet arrangement.
[00020] Conventionally, in the two or three wheeled vehicle, there is a problem of low torque at low speeds. For example, when the two wheeled vehicle is climbing a gradient on the road or heavy load is to be pulled so there is requirement of high torque at the rear wheel to pull the vehicle, and the transmission assembly may not be able to provide the same. Further, moving at low speeds with less torque results in loss of fuel economy. Furthermore, at higher speeds, a fixed transmission ratio gives limitation to speeds the vehicle can travel and results in loss of fuel economy. Hence, the transmission assembly may not be able to provide sufficient torque and the internal combustion engine may get switched off. Hence, the design of existing IC engine and its related components disposed is critical as it is designed in optimizing the engine layout to make in less bulky, deliver optimal torque to rpm performance and easy to assemble. Implementing transmission assembly in the existing layout involves extensive design and layout changes, which is not only difficult but also cumbersome and difficult to access. Further, a transmission assembly should be implementable with minimal changes in existing layout and minimum modification of frame component supporting the IC engine. Furthermore, there should be standardization of parts wherein single speed and two speeds can be introduced based on customer needs and requirements. An automatic or variomatic transmission is the an obvious choice as it can enable achieving reasonable mechanical efficiency, fuel consumption, but albeit at a cost. It can accommodate the range of vehicle needs and can operate smoothly. In this regard, the there are many transmission mechanism known in art.
[00021] Conventional transmission systems such as the automatic transmission systems have drawbacks wherein additional components are introduced causing layout constraints in designing a compact low weight power train as well as vehicle. Such additional components include the introduction of a new transmission stage in the existing single speed IC engine including gear train mechanism and multiple centrifugal clutches making the entire power train bulky and large in size. Such solution requires complete overhaul of the IC engine layout and involves extensive research and development and considerable investment to design a new IC engine with transmission system. The crankshaft/drive shaft of a compact powertrain and compact vehicle can accommodate only selected components, and hence any addition of new components for additional features are difficult. This also increases the cost of the vehicle extensively. Further, for having low weight IC engine, the current layout of IC engine has to been made compact, any changes in IC engine layout adversely affects its space occupied in the two wheeled vehicle and also involves complete redesign of frame assembly to support the IC engine as well as its location/mountings. Hence, there is a need to introduce transmission assembly with least and/or minimum changes in IC engine layout which can operate with single speed ratio & deliver optimal performance with good durability of the powertrain while overcoming all of the problems known in the art.
[00022] The chain transmission is a very important aspect in the effective design of the internal combustion (IC) engine and transmission assembly. Such configuration is primarily used because of higher center distance between crankshaft and driven shaft which results in reduced noise, low vibration operation and efficient working of the IC engine. During normal use of the internal combustion (IC) engine, there are zones of tension and slackness around different regions of the chain. Further, due to prolonged usage the chain stretches with normal use. Due to stretching and zones of tension and slackness whipping of chain occurs. To maintain optimum tension and support throughout the operating life of the chain, a chain tensioner system is used. Commonly in smaller capacity single cylinder internal combustion (IC) engines a mechanical rake type tensioner is used, wherein a pushrod is operated by an elastic member such as a spring exerts a constant pressure of the chain. The chain tensioner is designed to facilitate the movement of a pushrod with sufficient forward stroke to maintain optimum tension in the chain by exerting pressure on the pivot chain guide. When the chain shows signs of decreasing tension, the tensioner pushes the chain to bring back the tension to the optimum value. The pushrod is designed to only move in one direction, and backward stroke is prevented by a ratchet mechanism in which a ratchet interlocks on a serrated tooth provided on an exposed part of the pushrod. The positive bias force on a pushrod by the elastic member pushes on the chain guide to maintain optimum tension. There is normally a housing which encloses the pushrod and the elastic member. The pushrod is keyed to the housing so that it cannot rotate along its length. The elastic member is secured to the housing and is connected to one end of the pushrod such that, the space occupied by the part of the pushrod and elastic member completely forms an enclosed chamber.
[00023] The inability of complete forward stroke movement of the pushrod increases the noise generated from the movement of chain, and consequently results in chain whipping. Such issues restrict the internal combustion (IC) engine to reach its maximum performance. Hence, it is very essential to maintain optimum tension within the chain throughout as it increases chain life and provides for smooth operation of the internal combustion (IC) engine. Additionally, the chain is subjected to varying cyclic loads and any aggravating circumstances such as increase in tension results in failure due to fatigue load prematurely as compared to its rated life & durability. Increased tension also results in chain clinging to the driving sprocket and decreases the efficiency.
[00024] Further the change in existing designs of guide and tensioner leads to increase in the size of the crankcase and modifying the existing design leads to more cost to due complex machinability of intrinsic parts.
[00025] Moreover, the top land of the chain guide member is typically made of metal which is in direct contact with the chain. Due to direct and continuous movement of the chain over the guiding member made up of metal the friction increases which results into higher temperature. The rise in temperature severely affects the life of chain and the chain guiding member.
[00026] It is therefore an object of the present invention to provide the chain guide and tensioning assembly for the vehicle, which is capable of overcoming the above-mentioned problems and other problems known in the art.
[00027] It is therefore object of the invention to provide the chain guide and transmission assembly which ensures efficient and smooth chain drive operation.
[00028] It is yet another object of the invention to provide the chain guide and transmission assembly to maintain optimum tension within the chain throughout as it increases chain life, durability and provides for smooth operation of the internal combustion (IC) engine.
[00029] It is another object of the invention to avoid excess tension during its operation which enables the chain to avoid running hot.
[00030] It is object of the invention to provide the chain guide and tensioning assembly which result in less wear and avoids premature aging.
[00031] It is yet another object of the invention to provide the chain guide and tensioning assembly which can subjected to varying cyclic loads and any aggravating circumstances.
[00032] The aforesaid and other advantages of the present subject matter would be described in greater detail in conjunction with the figures in the following description with an embodiment of a two wheeled vehicle and its powertrain.

[00033] Figure 1. Illustrates a left side view of a two-wheeled vehicle (100) typically called a scooter, in accordance with an embodiment of the present subject matter. A frontward direction is indicated by an arrow F, and a rearward direction indicated by an arrow R provided in the top center of first figure. The vehicle is extending from the front direction to the rear direction along the vehicle longitudinal axis (F-R). In an embodiment; the two-wheeled vehicle (100) of the present subject matter comprises a frame which is conventionally an under-bone chassis frame which provides a generally open central area to permit “step-through” mounting by a rider. The vehicle (100) illustrated, has a step-through type frame assembly (FA). The step-through type frame assembly (FA) includes a head tube (103), a down tube (104) and a sub frame (105). The frame assembly (FA) extends from a front portion F to rear portion R of the vehicle. Further, the frame assembly (FA) extends downward from the anterior portion of the head tube (103) and then extends to a rear portion of the vehicle (100) in inclined manner. The pair of side-tubes (not shown) extends rearwardly from the other end of the main tube (not shown) and supports vehicular attachments such as a seat assembly (115), fuel tank assembly (not shown), a utility box (not shown) and a pillion hand rest (122). In the rear end of the two wheeled vehicle (100) a rear lamp assembly (119) and a rear mud-guard/rear fender (116) is provided. The rear guard (116) having deflector (120). The head tube (103) supports a steering tube (not shown) and further connected to the front suspension system (117) at the lower end. A handlebar support member (not shown) is connected to an upper end of the steering tube and supports a handlebar assembly (121) which is having a mirror (124). Two telescopic front suspension systems (117) (only one is shown) support a front wheel (113). The upper portion of the front wheel (113) is covered by a front fender (112) mounted to the lower portion of the steering shaft. There is a front brake (not shown) and a rear brake (not shown) arranged on the front wheel (113) and a rear wheel (108) respectively. The rear wheel (108) is supported towards the rear side of the frame assembly (FA) by an internal combustion (IC) engine (106) which is horizontally coupled swingably to the rear of the frame assembly (FA) of the two wheeled vehicle (100) through a rear suspension system (118). The traction motor (107) integrated to a rear wheel (108). In a preferred embodiment, the traction motor (107) is hub mounted on the rear wheel (108). An on-board battery (125) (not shown) drives the traction motor (107). The internal combustion (IC) engine (106) is mounted on a swing arm (123), which is swingably connected to the down tube (104) using a toggle link. The frame assembly (FA) is covered by plurality of body panels, mounted on the frame assembly (FA) and covering the frame assembly (FA), including a front panel (102), a leg shield (109), an under-seat cover (110), and a left and a right side panel (111). A glove box may be mounted to a leg shield (109). Over the rear wheel (108) a body panel is disposed of to support the seat assembly (108). The internal combustion (IC) engine (106) transfers the drive to the rear wheel (108) as it is coupled to it. The internal combustion (IC) engine (106) comprises a transmission system, said system disposed leftward of the internal combustion (IC) engine (106) in the vehicle width direction.
[00034] A front fender (112) is covering the front wheel (113). A floorboard (114) is provided at the step-through space provide above the down tube (104). A seat assembly (115) is mounted to the sub frame (105). A utility box (not shown) is disposed below the seat assembly (115). A fuel tank (not shown) is positioned below the utility box. A rear fender (116) is covering at least a portion of the rear wheel (108) and it is positioned below the fuel tank (not shown). One or more rear suspension(s) (118) are provided in the rear portion of the vehicle (100) for comfortable ride. The vehicle (100) comprises of plurality of electrical and electronic components including a headlight (101), a rear lamp assembly (119), a transistor controlled ignition (TCI) unit (not shown), a starter motor (not shown).
[00035] Figure 2 illustrates a left side view of the rear portion of the two wheeled vehicle (100) illustrating a swingable internal combustion (IC) engine (106) in accordance with the embodiment of the present subject matter. The internal combustion (IC) engine (106) comprises a cylinder block (602) (as shown in fig. 4) includes a cylinder bore (not shown), a piston (not shown) reciprocating in the cylinder bore (not shown), a cylinder head (601) (as shown in Fig. 6) located above the cylinder block (602) and a combustion chamber interposed between the cylinder head (601) (as shown in Fig. 6) and the cylinder block (602) (as shown in Fig. 6). The cylinder block (602) (as shown in Fig. 6) is covered by deflection cover (202). The cylinder head (601) (as shown in Fig. 6) comprises intake valve (not shown) and outlet valve (not shown) which control the intake of air fuel mixture inside the combustion chamber, and controls the exit of exhaust gases after combustion respectively. The cylinder head (as shown in Fig. 6) is covered by the cylinder head cover (201) during operation of the internal combustion (IC) engine (106), the burning of air fuel mixture occurs in the cylinder block (602) (as shown in fig. 6). The forces generated due to combustion of air fuel mixture is transferred to a piston (not shown) which is capable of reciprocating inside the cylinder block (602) (as shown in fig. 6), and this reciprocating motion is transferred to rotary motion of the crankshaft (301) (as shown in Fig. 3) though a connecting rod (not shown) by the slider crank mechanism. Typically, in a two wheeled vehicle (100) such as a scooter, a swinging internal combustion (IC) engine (106) is located below the seat assembly (115) at a lower rear portion of the vehicle (100). The internal combustion (IC) engine (106) is swingably supported by and attached to the frame assembly (FA) of the two wheeled vehicle (100). A single speed transmission assembly(TA) forms a part of the internal combustion (IC) engine (106) and is disposed on the rear portion of the internal combustion (IC) engine (106) and mounted so as to be disposed on right or left of the two wheeled vehicle (100). In first embodiment, the transmission assembly (TA) is disposed so as to be oriented towards the left of the two wheeled vehicle (100) as viewed from the rear direction of the two wheeled vehicle (100). The transmission assembly (TA) is enclosed within a crankcase LH (204) on the rear side of the internal combustion (IC) engine (106) and the transmission assembly(TA) is enclosed by a housing (203) thus forming an enclosed space. The transmission means (305) (as shown in Figure 3) connects the drive sprocket (401) (as shown in Figure 4) to a corresponding driven sprocket (306) (as shown in Figure 3). Further the wheel sprocket (208) is disposed outside the housing (203) which receives rotary motion from the output/ driven shaft (302) (as shown in Figure 3) of the gear train mechanism on the rear wheel (108).The final drive to the rear wheel (108) of the two wheeled vehicle (100) is usually a positive drive such as sprocket and chain arrangement(207) this ensures the transmission ratio between the drive sprocket (401), driven sprocket (306) and wheel sprocket (208) to provide a gear ratio multiplication. This way rotary motion is finally transferred to the rear wheel (108). The drive shaft (301) is also known as crankshaft so these words have been interchangeably used throughout the description. The cooling fins (206) are provided on the outer surface of the housing (203) to dissipate the excess heat from the transmission of internal combustion (IC) engine (106). Further an adjustment screw (205) is provided at the bottom of the crankcase (RH, LH).
[00036] Figure 3 illustrates the left side view of the internal combustion (IC) engine (106) and transmission assembly (TA) where some constituent parts are omitted. The primary transmission is from the drive sprocket (401) (as shown in Figure 4) to the driven sprocket (306). The transmission means (305) transfers power from the internal combustion (IC) engine (106) to driven shaft (302). The transmission guiding and tensioner assembly (GTA) (as shown in Fig. 7a) comprises guide member assembly (307) and tensioning member (402) (as shown in Fig. 7a). The guide member assembly (307) comprises a guide retainer member (805) (as shown in fig. 8) and top land part (801) (as shown in Fig. 8). The top land part (801) provided with side walls (802) (as shown in fig. 8) is in slideable contact with the transmission means (305) which guide the transmission means (305) during its travel as tensioning member (402) configured to exert force on guide member assembly (307) to keep said top land part (801) in contact with the transmission means (305),
[00037] Figure 4 illustrates the perspective view of transmission assembly where few parts are omitted, the guiding and tensioning assembly (GTA) comprises tensioning member (402) and guide member assembly (307), where a mechanical rake type tensioning member (402) is used, wherein a plunger (404) is operated by an elastic member such as a spring (not shown) exerts a constant pressure on the transmission means (305). The tensioning member (402) is designed to facilitate the movement of a Plunger (404) with sufficient forward stroke to maintain optimum tension in the transmission means (305) by exerting pressure on the pivot guide member assembly (307). When the transmission means (305) shows signs of decreasing tension, the tensioning member (402) pushes the transmission means (305) to bring back the tension to the optimum value. The plunger (404) is designed to only move in one direction, and backward stroke is prevented by a ratchet mechanism in which a ratchet interlocks on serrated teeth provided on an exposed part of the plunger (404). The positive bias force on a plunger (404) by the elastic member pushes on the guide member assembly (307) to maintain optimum tension. There is normally a housing which encloses the plunger (404) and the elastic member. The plunger (404) is keyed to the housing so that it cannot rotate along its length. The guide retainer member (805) configured to have at least one elongated member (403) extending in lateral axis C – C’ of the vehicle (100) provided on at least one side of the guide retainer member (805) (as shown in Fig. 8). The tensioning member (402) is applying force from the bottom end to the elongated member (403) of the guide member assembly (307).
[00038] Figure 5 illustrates the exploded view of the present embodiment where it represents the crankcase (RH, LH) in which transmission assembly (TA) is present which extends rightward (RH) and leftward (LH) in the internal combustion engine (106) width direction said crankcase (RH, LH) comprising of a top surface, and a bottom surface, and a plurality of side surfaces of the crankcase, wherein the side surfaces are substantially vertical and configured to extend between the top surface and the bottom surface. The part extended in rightward (RH) direction is known as a crankcase RH (501) and the part extended in leftward (LH) direction is known as a crankcase LH (204). Similar to the crankcase (RH, LH), a drive shaft (301) also extends rightward (RH) and leftward (LH) in the internal combustion (IC) engine (106) width direction. This extension results in two parts of the drive shaft (301)/crankshaft (301), first one is known as a crankshaft RH as the crankshaft extends in rightward (RH) direction and second one is known as a crankshaft LH as the crankshaft (301) extends in leftward (LH) direction. The crankcase LH (204) is covered by housing (203). This housing makes the system leak proof and enables effective lubrication. In the crankcase LH (204), of horizontally disposed internal combustion engine (IC) engine (106) such as that of scooter-type two-wheeled vehicles (100), an oil sump (not shown) is provided in the bottom-side of the crankcase LH (204) for continuous lubrication and cooling of a piston (not shown) and a plurality of piston cylinder wall (not shown) and other parts of the internal combustion (IC) engine (106). The lubrication and cooling of the piston (not shown), the plurality of piston cylinder wall (not shown) and other parts of the internal combustion (IC) engine (106) begins once an operation cycle of thermal energy conversion into mechanical energy begins. Once the operation cycle starts, rotation of the drive shaft (301) also starts. The transmission oil chamber ensures the continuous lubrication of the transmission means (305), Further the lubricant sump (not shown) is also provided in which desired lubricant level is maintained and to ensure that the components like transmission means (305) at least partially immersed in the lubricant. The motion of the transmission means (305) causes lubricant splashing and lubrication of the components. A gauge oil level (502) is also provided on the crankcase RH (501) which enables the user to check the lubricant oil level. A spring loaded centrifugal clutch (308) fixedly attached to the crankshaft LH using fastening means. The fastening means includes nuts (504). The centrifugal clutch (308) ensures that at low to idle speeds the power transmission from the internal combustion (IC) engine (106) is disengaged to the rear wheel (108) as spring loaded centrifugal shoe unit fixedly attached to the crankshaft (301) and capable of expanding and engaging with the outer hub (308a) on rotation of the crankshaft (301) beyond a predetermined speed thereby rotates drive sprocket (401). The drive sprocket (401) is welded with the outer hub (308a) known as drum. So on attaining certain rpm the drive sprocket (401) rotates the driven sprocket (306) through transmission means (305). The transmission means (305) connects the drive sprocket (401) to a corresponding driven sprocket (306). A spacer (503) is placed between the drive sprocket (401) and one way clutch assembly (607) (as shown in Fig.6) to maintain gap which avoids rotation. The direction of rotation of the transmission means (305) is made common with the internal combustion (IC) engine (106) and the rear wheel (108). The direction of power transfer makes the upper side tighter and lower side slack. To control the slack side the guiding and tensioner assembly (GTA) is provided. The guide member assembly (307) is mounted on the rear side of the crankcase LH (204), Further; the tensioning member (402) is mounted on the housing (203) from the rear bottom end using at least two bolts (505).
[00039] Figure 6 illustrates cut section of figure 3 taken along plane D-D’ and represents the crankcase (RH, LH) in which transmission assembly (TA) is present which extends rightward (RH) and leftward (LH) in the internal combustion engine (IC) engine (106) width direction, the cylinder head (601) is covered by the cylinder head cover (201) during operation of the internal combustion (IC) engine (106), the burning of air fuel mixture occurs in the cylinder block (602). The forces generated due to combustion of air fuel mixture is transferred to a piston (not shown) which is capable of reciprocating inside the cylinder block (602) and this reciprocating motion is transferred to rotary motion of the crankshaft (301) though a connecting rod (not shown) by the slider crank mechanism. Further, as per the internal combustion engine (IC) engine (106) construction, on the drive shaft LH a gear oil pump drive (GOPD) (612) is mounted and the gear oil pump drive (GOPD) (612) are mated with an oil pump assembly (not shown). With all above-mentioned parts on the crankshaft LH. Due to that rotation of the drive shaft (301), the gear oil pump drive (GOPD) (612) also starts rotating, since the gear oil pump drive (GOPD) (612) is in contact with the oil pump assembly (not shown) which results the movement of lubricant oil from oil sump (not shown) to lubricate and cool the piston (not shown), the plurality of piston cylinder wall (not shown) and other parts of the internal combustion (IC) engine (106). The crankcase RH (501) having cooling system mounted using fastening means (605) on an extended portion of crankshaft (301) juxtaposes outside the crankcase RH (501) over which the cooling system is operably secured. The cooling system in general comprises a shroud (604) with plurality of ribs (not shown), and a cooling fan (603). The cooling fan (603) operates at a same speed of drive shaft (301) and generates air flow. The cooling system efficiency is directly proportional to the air flow coming out from the cooling fan (603). The cooling fan (603) throws out more air coming out from the internal combustion (IC) engine (106). In order to increase the cooling rate, it is recommended to have higher fan air flow rate so shroud (604) is provided ahead of the cooling fan (603). The internal combustion (IC) engine (106) comprises the transmission assembly (TA) freely mounted on an extended portion of the crankshaft LH. A portion of crankshaft (301) juxtaposes outside the crankcase LH (204) over which the transmission assembly (TA) is operably secured. The transmission assembly (TA) is designed to be of the centrifugal clutch (308) with a two one way clutches (607, 608). The first one way clutch assembly (607) having back plate (607a). The first one way clutch assembly (607) is held in position on the crankcase LH (204). The crankcase LH (204) is completely enclosed on its sides except for relevant opening for accommodating the crankshaft (301) and the output shaft/driven shaft (302). An oil pump cover (610) is supported by crankcase LH (204).
[00040] A first one way clutch assembly (607) comprises back plate (607a) mounted on drive shaft (301). Ahead of first one way clutch assembly (607) a drive sprocket (401) is mounted on the crankshaft LH. The motor having pinion gear (not shown) rotates the back plate (607a) through the intermediate gear (304) (as shown in fig. 3) via ring gear (303) (as shown in fig. 3). The back plate (607a) enables the rotation of the drive shaft (301) for cranking the internal combustion (IC) (106) and an ignition system (not shown) enables delivering of spark. The second one way clutch assembly (608) is mounted on the driven shaft (302) using fastening means. The fastening means includes nuts (504). The power is transmitted from the drive sprocket(401) to the second one way clutch (608) through driven sprocket(306) via transmission means(305), wherein said second one way clutch assembly (608) comprising back plate (608a) which is internally splined and mounted on external splines on the end of the driven shaft(302) disposed parallel to the drive shaft (301) towards the rear of the internal combustion (IC) engine (106) and is supported by two roller bearings (609) on the rear portion of the crankcase LH (204).The power from back plate(608a) transmitted to the driven shaft(302) and then finally to the rear wheel(108) through chain arrangement (207). The first one way clutch assembly (607) ensures that, the drive is not transferred from the crankshaft (301) to the ring gear (303). The driven sprocket (306) engage with the rollers (611) of second one way clutch assembly (608), where the second one way clutch assembly (608) transmit power to back plate (608a) as both are bolted. Moreover, the second one way clutch assembly (608) is to prevent the rotary motion drive from transferring back to the crankshaft (301) and the transmission assembly (TA) from the driven shaft (302) during the ideal running of vehicle on road and when vehicle is powered by motor. The drive shaft (301) is mounted with an electrical machine (606). In one embodiment, the electrical machine (606) is connected to the drive shaft (301). In a preferred embodiment, the electrical machine (606) includes magneto or integrated stator generator (ISG). The integrated stator generator (ISG) help in reduction of size of motor. Hereinafter, the terms electrical machine (606) and magneto (not shown) are interchangeably used. The magneto (not shown) includes a rotor (not shown) and a stator (not shown). The rotor (not shown) is connected to the crankshaft (301). The rotor (not shown) includes magnetic members and the stator (not shown) is provided with plurality of windings (not shown). The guiding and tensioning assembly (GTA) is disposed between the driven shaft (302) and crankshaft (301) and specifically said guiding and tensioning assembly (GTA) is disposed on the slack side of the transmission means (305).
[00041] Figure 7a illustrates the rear cross sectional view across plane A- A’ shown in Fig. 6 as per present embodiment. The guide member assembly (307) comprises a guide retainer member (805) (as shown in Fig. 8) and top land part (801) (as shown in Fig. 8). The guide retainer member (805) configured to have at least one elongated member (403) extending in lateral axis C – C’ axis of the vehicle (100). The elongated member (403) provided on at least one side of the guide retainer member (805). Further the elongated member (403) is provided with the ribs (701) except at contact point area to further strengthen the energy transfer points. The tensioning member (402) having a plunger (404) which is configured to be in direct contact with the elongated member (403) of the guide retainer member (805). The plunger (404) having end portion with slide member which protrudes inside the housing (203) to press the transmission means (305) through guide member assembly (307). The plunger (404) which is slidably defining in a body of said tensioning member (402) is moving in one direction so as to protrude from the body to inside the housing (203).
[00042] Figure 7b illustrates the rear cross sectional view across plane B- B’ (as shown in Fig. 6) as per present embodiment. The tensioning member (402) is mounted at the bottom of the housing (203) through at least two bolts (505). The plunger (404) (as shown in figure. 7a) exerts force on the elongated member (403) (as shown in figure. 7a) and move the guide member assembly (307) about the pivot end. The guide retainer member (805) (as shown in figure. 8) configured to have boss part (803) and a pivot hole (804) on one of the end where it is mounted on the housing (203) using at least one bolt (309) passing through the pivot hole (804) (as shown in figure. 8). The bolt (309) having shank which is configured to have more width than the width of the boss part (803) (as shown in figure. 8) which gives some gap to the guide member assembly (307). This gap will allow guide retainer member (805) (as shown in figure. 8) to rotate and avoid it from getting locked with the bolt (309). The elongated member(403) ensures the no foul with oil pump sump(not shown) because if the tensioning member (402) mounted directly at the bottom of the guide member assembly (307) then the tensioning member (402) comes at mid of crankcase LH(204) and housing (203), which leads to fouling with the oil sump(not shown) of the internal combustion (IC) engine(106), Any attempt to accommodate tensioning member (402) at the exact bottom of guide member assembly (307) will cause decrease in the volume of the oil sump (not shown)which further deceases the volume of engine oil and results in high temperature issue because of less lubrication. This less lubrication and high temperature issues lead to less durability of parts and finally to internal combustion (IC) engine (106) cease.
[00043] Figure 8 illustrates a perspective view of the guide retainer. The guide retainer member (805) having the top land part (801) provided with side walls (802) to avoid slippage of transmission means (305). The transmission means (305) includes chain, belt etc. The top land part (801) is snap fitted into the guide retainer member (805). The guide retainer member (805) having elongated member (403) to which the plunger (404) of the tensioning member (402) is in direct contact. The elongated member (403) is surrounded by ribs (701) on at least three sides. The boss part (803) is provided to mount the guide member assembly (307) on the crankcase LH (204). A bolt (309) is passed through the pivot hole (804) around whom the guide member assembly (307) is rotatable. The guide member assembly (307) should withstand the force coming from the transmission means (305) and tensioning member (402) and hence it is made up of metal. The metal includes aluminium or like. The top land part (801) is made up of polymeric material ensures more smooth engagement with the transmission means (305). As per another embodiment, the top land part (801) can be integral of the retainer member & made of polymeric material.
[00044] Figure 9 illustrates the left side view of the internal combustion (IC) engine (106) and transmission assembly (TA) where the few parts are omitted. As per second embodiment the tensioning member is integrated to the guide member to become as single unit. The crankcase LH supports an oil pump cover (903), where the oil pump cover (903) configured to have at least one extended boss (904) with mounting holes. The integrated guiding and tensioning assembly (IGTA) is supported on extended boss (904) of the oil pump cover (903) using the mounting means. The mounting means includes bolt (910) to mount the integrated guiding and tensioning assembly (IGTA). The integrated guiding and tensioning assembly (IGTA) configured to have a key hole (907) on the bottom half wherein said key hole (907) accommodates the pre compressed spring (909) to exert a positive bias force on the transmission means (305). The transmission means (305) includes chain. The bolt (910) provides the base for the pre compressed spring (909). The bolt (910) having shank is configured to have more width than the width of the integrated guiding and tensioning assembly (IGTA) which gives adequate working clearance to the integrated guiding and tensioning assembly (IGTA). This gap will allow integrated guiding and tensioning assembly (IGTA) to translate/move freely without getting locked with the bolt (910). Further the spring (909) is configured to have a cylindrical pin (not shown) to avoid lateral movement. The integrated guiding and tensioning assembly (IGTA) movement is controlled by the C - shape wall (902) provided on the rear half of the crankcase LH (901). The integrated guiding and tensioning assembly (IGTA) is positioned between the drive shaft (301) and driven shaft (302) such that it exerts required force on the slack side of the transmission means (305). The guide member having top land (905) with sidewalls (906) which ensures the smooth movement of transmission means (305). Further integrated guiding and tensioning assembly (IGTA) configured to have pockets or cavities (908) on both the sides which reduces the weight. The top land (905) is made of plastic and the tensioning member is made of metal. The integrated guiding and tensioning assembly (IGTA) withstands the forces exerted by the transmission means (305) and the pre compressed spring (909).
[00045] The present invention as per first and second embodiment the guiding and tensioning assembly is introduced without having a large and bulky design of IC engine and its related components disposed within it is critical as it is designed in optimizing the engine layout to make in less bulky and easy to assemble.
[00046] The present invention as per first and second embodiment is implemented in existing transmission assembly (TA) without extensive design and layout changes, which is easily accessible.
[00047] The present invention as per first and second embodiment is also implementable with minimal changes in existing layout and minimum modification of frame component supporting the internal combustion (IC) engine (106). Furthermore, there can be standardization of parts wherein single speed and two speed can be introduced based on customer needs and requirements.
[00048] The present invention as per one and second embodiment ensures the transmission in the existing design of the internal combustion (IC) engine and transmission assembly as it results in reduced noise, and low vibration operation and efficient working of the internal combustion (IC) engine (106).
[00049] The present invention as per first embodiment maintains optimum tension and support throughout the operating life and good durability of the transmission means (305), as per first embodiment a tensioning member (402) is used. The tensioning member (402) is designed to facilitate the movement of a plunger (404) with sufficient forward stroke to maintain optimum tension in the transmission means (305) by exerting pressure on the pivot guide member assembly (307). When the transmission means (305) shows signs of decreasing tension, the tensioning member (402) pushes the transmission means (305) to bring back the tension to the optimum value. The plunger (404) is designed to only move in one direction, and backward stroke is prevented by a ratchet mechanism in which a ratchet interlocks on a serrated teeth provided on an exposed part of the pushrod. The positive bias force on a plunger (404) by the elastic member pushes on the guide member assembly (307) to maintain optimum tension. There is normally a housing which encloses the pushrod and the elastic member. The plunger (404) is keyed to the housing so that it cannot rotate along its length. The elastic member is secured to the housing (203) and is connected to one end of the plunger (404) such that, the space occupied by the part of the plunger (404) and elastic member completely forms an enclosed chamber.
[00050] The present invention as per first embodiment counters the inability of complete forward stroke movement of the plunger (404) which increases the noise generated from the movement of transmission means (305), and consequently avoids whipping by positioning the tensioning member (402) at offset position with respect to the guide member assembly (307) and the top land part (801) area remain in continues touch with the transmission means (305). This further leads to maintain optimum tension within the transmission means (305) throughout as it increases life and provides for smooth operation of the internal combustion (IC) engine.
[00051] The present invention as per second embodiment counters the inability in known art of excreting required force through the integrated guiding and tensioning assembly (IGTA) the top land (905) of which continuously remains in contact with the transmission means (305) and controlled by the C-shaped wall provided on the crankcase LH (901).
[00052] The present invention as per first and second embodiment counters the excess tension at large duration of operation leading to the transmission means (305) to run cooler and excessive wear and premature aging by having top land part (801, 905) made of polymeric material and the guide member assembly (307) made of metal which includes aluminum. In second embodiment integrated guiding and tensioning assembly (IGTA) except top land (905) made up of metal. The metal includes aluminum.
[00053] The present invention as per first and second embodiment having top land part (801, 905) with side walls (802, 906) which counters the varying cyclic loads and any aggravating circumstances such as increase in tension results in eliminating premature durability failure due to fatigue load as compared to its rated life and ensures the smooth operation.
[00054] The present invention as per first embodiment can also be implemented without change in design of the crankcase (RH, LH) as in first case the tensioning member (402) is introduces from the bottom of the housing (203) and the guide member assembly (307) is mounted in the crankcase LH (204) without any significant modification of the existing design which further reduces the cost as less complex machinability of intrinsic parts is required.
[00055] The present invention as per first embodiment having top land part (801) snap fitted into the guide member assembly (307) which ensures ease of serviceability as the top land part (801) subjected to tear and wear due to direct contact with the transmission means (305) hence the top land part (801) can be removed from the guide retainer member (805) without detaching the whole assembly.
[00056] The present invention as per first and second assembly leads to less assembly time and more production rate as the part count is reduced and the whole assemble remain within ergonomically reach of the workmen while assembling because as per first embodiment the guide member assembly (307) can be mounted using only one bolt (309) and tensioning member (402) can be mounted using two bolts provided at the bottom of the housing (203). Further as per second embodiment the guide and tensioning assembly is integrated and can be assembled using only one bolt (910).
[00057] The present invention as per second embodiment integrated guiding and tensioning assembly (IGTA) leads to reduction of part count and reduces the cost.
[00058] 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
FA - Frame assembly
GTA – Guiding and tensioning assembly
IGTA – Integrated guiding and tensioning assembly
TA – Transmission assembly
RH, LH - Crankcase
F- Front
R –Rear
C – C’ – Lateral axis
Y – Y’ – Longitudinal axis
100 – Vehicle
101 - Headlight
102 - Front panel
103 - Head tube
104 - down tube
105 - Sub frame
106 - Internal combustion (IC) engine
107 - Traction motor
108 - Rear wheel
109 - Leg shield
110 - Under-seat cover
111 - A left and a right side panel
112 - Front fender
113 - Front wheel
114 - Floorboard
115 - Seat assembly
116 - Rear fender
117 – Front suspension(s)
118 – Rear suspension
119 – Rear lamp assembly
120 – Deflector
121 – Handle bar assembly
122 – Pillion handle rest
123 – Swing arm
124 – Mirror
125 – On board battery
201 – Cylinder head cover
202 – Deflector cover
203 – Housing
204 – Crankcase LH
205 – Adjustment screw
206 – Fins
207 – Chain arrangement
208 – Wheel sprocket
301 – Crankshaft/drive shaft
302 – Driven shaft/output shaft
303 – Ring gear
304 – Intermediate gear
305 – Transmission means
306 – Driven sprocket
307 –guide member assembly
308 – Centrifugal clutch
308a – Outer hub
309 – Bolt
401 – Drive sprocket
402- Tensioning member
403 – Elongated member
404 – Plunger
501 – Crankcase RH
502 – Gauge oil level
503 – Spacer
504 – Nut
505 – At least two Bolts
601 – Cylinder head
602 – Cylinder block
603 – Cooling fan
604 - Shroud
605 – Fastening means
606 – Electrical machine
607 – First one way clutch assembly (Back plate 607a)
608 – Second one way clutch (Back plate 608a)
609 – Roller bearing
610 – Oil pump cover
611 – Roller
612 – Gear oil pump drive (GOPD)
701 – Ribs
801 – Top land part
802 – Side walls
803 – Boss part
804 – Pivot hole
805 – Guide retainer member
901 - Crankcase LH
902 – C- Shape
903 – Oil pump cover
904 – Extended boss
905 – Top land part
906 – Side walls
907 – Key hole
908 – Pocket/Cavities
909 – Spring
910 - Bolt