[0001] The present subject matter relates, in general to a vehicle, and in particular, to vehicle having a primary shaft assembly for providing different range of torque to a vehicle for pulling heavy loads.

BACKGROUND

[0002] Transmission systems, generally known as gearbox are used in a vehicle to regulate an amount of power transmitted from an engine to wheels. Generally, a gearbox includes a set of gears, where each a pair of meshed gears have a gear ratio to vary torque for transferring power to the wheels of the vehicle. Generally, the gear ratio denotes the ratio of number of rotation of the output shaft makes when the input shaft rotates one rotation. Generally, the engine includes a crankshaft coupled to an input shaft of the gearbox through a clutch assembly. Further, based on a load to be hauled, a gear ratio may be selected from the set of gear ratios of the gearbox to provide adequate power for hauling the load.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of the system(s) in accordance with the present subject matter are described, by way of examples only, and with reference to the accompanying figures, in which:

[0004] Fig. 1A-1B illustrate a various view of the vehicle in accordance with an embodiment of the present subject matter

[0005] Figs. 2A-2D illustrate different views of an engine bay of the vehicle in accordance with an embodiment of the present subject matter DETAILED DESCRIPTION

[0006] Generally, depending on the load, an amount of torque needed to haul the load may be varied. For example, large amount of torque may be needed in cases where the vehicles haul heavy loads or where the vehicle moves on a hilly terrain or an inclined terrain. On the other hand, low torque may be adequate for the vehicles hauling normal load or when moving over a levelled terrain. Conventionally, the gearbox of the vehicle is equipped includes a set of gears that may be selected to vary torques and/or speed according to the load of the vehicles. During operation, the gearbox outputs the power at different speeds and torques to a differential of the vehicle based on selected gear ratio.

[0007] Conventional gearbox may have limited ability in terms of the range of variation in torque that can be provided. Further, in order to develop the ability of greater variations in the gear ratios, additional gears may be added. However, addition of extra gears may increase size and weight of the gearbox. Moreover, an engine bay may be redesigned to accommodate a larger gearbox, that sometime, may not be possible owing to space constraints in the vehicle. Moreover, addition of extra gears may result in additional manufacturing and operational cost of the gearbox.

[0008] The present subject matter relates to various aspects for providing a range of torques to a vehicle, for instance, for enhancing the range of torque available for the vehicle. For example, the vehicle implementing the present subject may be able to achieve various variations of torque for pulling heavy loads on inclined terrain as well as being able to effectively operate on level terrain. According to an aspect, an engine shaft, may be provided that may be coupled to a crankshaft of the engine where a plurality of drive gears may be mounted on the engine shaft. In addition, a primary shaft assembly may also be provided that may be operably coupled to the engine shaft. In one example, the primary shaft assembly may include a primary shaft to transmit power from the engine shaft to a gearbox, a plurality of driven gears mounted on the primary shaft, and a lever to actuate the driven gears. According to an aspect of the present subject matter, the primary shaft may be adapted to engage with the engine shaft for providing a range of torques to the vehicle. In one example, each of the plurality of driven gears is engageable with one or more of the plurality of drive gears. Further, the lever is operably coupled to the plurality of driven gears to selectively engage the driven gear among the plurality of driven gears with a drive gear among the plurality of drive gears for selecting a gear ratio between the drive gear and driven gear. Further, an amount of torque is converted by the primary shaft based on the selected driven and drive gear. Further, the torque is transferred to a gearbox for further variation by the gearbox.

[0009] The present subject matter allows variation of torques before the torque is transmitted to the gearbox by a set of drive and driven gears. Thus, the number of variations in the torque of the vehicle is increased without making substantial modification in the layout. Further, the primary shaft assembly is simple in design and can easily be mounted in between the engine and the gearbox. Moreover, the primary shaft assembly having driven gears are attached outside of the gearbox, resulting in compactness of the gearbox. Further, the present subject matter provides a cost effective transmission system with reduced number of parts.

[0010] These and other advantages of the present subject matter would be described in greater detail in conjunction with the following figures. While aspects relating to cooling of a combustion chamber of an engine as described above and henceforth can be implemented in any number of different configurations, the embodiments are described in the context of the following system(s).

[0011] Fig. 1A-1B i 11 u s tr a t e a v e h i c l e 1 00 , i n a c c o r d a n c e w i th o n e implementation of the present subject matter. The vehicle 100 includes an engine bay 102 that may house an engine, a primary shaft assembly having a lever, a gearbox, and an engine shaft. In one example, the vehicle 100 may a three- wheeled vehicle, a four-wheeled vehicle, a multi axle vehicle, or the like. In one

example implementation, the engine along with the primary shaft assembly are collectively referred to as an engine assembly 104. The engine assembly 104 is adapted to provide a range of torque to the gearbox depending upon a load to be hauled or the terrain which the gearbox can further vary when the engine is running. Further, the gearbox is also capable of varying the torques based on the load of the vehicle 100. The engine assembly 104 may include a set of drive gears and driven gears and the lever to selectively engage with the driven gear and the drive gears to vary the torque. The structural and operation of the engine assembly 104 will be described in detail in with respect to Fig. 2 A onwards.

[0012] In the illustrated implementation, the engine assembly 104 may be positioned at a rear end of the vehicle 100 as shown in Fig. 1A. Although the engine assembly 104 is shown to be mounted at the rear of the vehicle 100, it may be understood that the engine assembly 104 may also be mounted in either front or middle of the vehicle 100. The vehicle 100 may include a steering system 106 to steer the vehicle. In addition, the vehicle 100 may further include a handle 108, a cable 110 connected between the lever and the handle 108. Further, the handle 108 may be positioned at a front end, under the steering system 106, of the vehicle 100. In another example, the handle 108 may be positioned ergonomically so that a driver may easily access the handle 108 to operate the lever. For instance, the handle 108 for operating the lever 216 is positioned substantially at a distance of 1.5 foot, which in other words is equal to the distance of reach of driver’s forearm from his seated position. Such an optimal location of the handle 108 ensures that the driver operates the handle without difficulty. Further, a driver or an operator may operate the handle 108 to vary the torque transmitted to the gearbox. A manner by which the torqu e i s v ariated may be exp lained in s ub s equent

embodiments.

[0013] Figs. 2A-2D illustrate different views of the engine bay 102 of the vehicle 100 in accordance with an embodiment of the present subject matter. The engine bay 102 may house the engine assembly 104 that may further include the engine 202, the primary shaft assembly 204, the gearbox 206, and an engine shaft 208. The gearbox 206 may be coupled to the engine assembly 104 through a clutch assembly (not shown). In one example, the gearbox 206 may be synchromesh gearbox. In one embodiment, the gearbox 206 can be any gearbox known in the art that receives power from the primary shaft 212 and provides various range of torques to wheels of the vehicle. Further, an operation of the gearbox 206 is well known in the art, so it is avoided for conciseness of the specification

[0014] According to an aspect, the engine assembly 104 may include the primary shaft assembly 204 having a primary shaft 212 that is adapted to selectively engage with the engine shaft 208 of the engine 202 through a coupling for providing a range of torques to the gearbox 206. Further, the primary shaft 212 may be coupled to the gear box 206 as shown in Figs. 2A-2C.

[0015] In one embodiment, the engine assembly 104 may include the engine shaft 208 coupled to a crankshaft (not shown) of the engine 202. In one example, the engine shaft 208 may include a plurality of drive gears 210 mounted thereon. In one embodiment, the plurality of drive gears 210 may be mounted on the engine shaft 208. In one example, the drive gears 210 may be mounted on the engine shaft 208 using various means, such as, but not limited to, keys or splines. In another example, the plurality of drive gears 210 may be formed as an integral part of the engine shaft 208. In the illustrated example, the power may be transmitted from the engine shaft 208 through the drive gears 210. Further, each drive gear 210 in the plurality of drive gears 210 may be serially arranged after another drive gear along a length of the engine shaft 208.

[0016] According to an aspect, the primary shaft assembly 204 may be positioned adjacent to the engine shaft 208 and may be engagably coupled to the engine shaft 208. The primary shaft assembly 204 includes a primary shaft 212 that may transmit power from the engine shaft 208 to the gearbox 206. The primary shaft assembly 204 can further include a plurality of driven gears 214 mounted on the primary shaft 212. The plurality of driven gears 214 is mounted on at a first end of the primary shaft 212 adjacent with the plurality of drive gears 210. In one example, the plurality of driven gears 214 may be mounted on the primary shaft 212 through splines for preventing relative motion between the plurality of driven gears 214 and the primary shaft 212. In other words, the splines are provided on the primary shaft 212 so that the plurality of driven gears 214 and the primary shaft 212 may rotate substantially at same speed.

[0017] In another example, the plurality of driven gears 214 is mounted on the primary shaft 212 in such a way that the driven gears 214 can translate along a length of the primary shaft 212. In another embodiment, each driven gear of the plurality of driven gears 214 may be mounted serially to other driven gears of the plurality of driven gears 214 along the length on the primary shaft 212. In other words, each driven gear is arranged one after another gear serially along the length of the primary shaft 212. In one embodiment, each of the plurality of driven gears 214 may selectively engageable with one or more of the plurality of drive gears 210 to vary transmission of torque from the engine shaft 208 to the primary shaft 212. For example, each of the plurality of driven gears 214 can engage with one or more gears in the plurality of drive gears 210. Further, engagement of the plurality of drive gear 210 and the plurality of driven gears 214 may provide a range of gear ratio to vary the torque during transmission.

[0018] According to an aspect, the primary shaft assembly 204 having the lever 216 is operably coupled to the plurality of driven gears 214, the lever 216 being configured to selectively engage a driven gear among the plurality of driven gears 214 with a drive gear among the plurality of drive gears 210 for selecting a gear ratio between the drive gear and the driven gear. In other words, the lever 216 is adapted to translate the driven gears 214 along the primary shaft 212 to selectively engage the driven gear 214 with the drive gear 210. Further, as the clutch mechanism is not attached to the primary shaft assembly 204, the lever 216 is needed to be operated in an inactive state of the engine 202 to avoid damages of the plurality of drive gears 210 and the plurality of driven gears 214.

[0019] The selective engagement of the driven gear and drive gear is to select a gear ratio between the driven gear and drive gear. The gear ratio is ratio of number of rotation of the primary shaft 212 makes when the engine shaft 208 rotates one rotation. Further, engagement of the plurality of drive gears 210 with the plurality of driven gears 214 may result in different gear ratios to provide a range of torques for transmitting power to the gearbox 206.

[0020] According to an aspect, the plurality of drive gears 210 may include a first drive gear 210-1 and a second drive gear 210-2 and the plurality of driven gears 214 includes a first driven gear 214-1 and a second driven gear 214-2. Further, the first drive gear 210-1 and the first driven gear 214-1, when engaged, may have a gear ratio to provide high torque to the primary shaft 212. Similarly, the second driven gear 214-2 and the second drive gear 210-2, when engaged, may have a gear ratio to provide low torque to the primary shaft 212. In one example, the lever 216 may be operated to engage either of the first driven gear 214-1 with the first drive gear 210-1 for proving high torque to the primary shaft 212 or the second driven gear 214-2 with the second drive gear 210-2 for providing low torque to the primary shaft 212. Although the current illustration shows two drive gears and two driven gears, it may be multiple drive gears and driven gears may be used.

[0021] In one embodiment, the lever 216 may include a locking mechanism

(not shown) to lock the lever 216 during the movement of the vehicle. In another embodiment, the lever 216 may be coupled to a pulley 216-1. The plurality of driven gears 214 is slidably mounted on the primary shaft 212 to selectively engage any one gear of the plurality of driven gears 214 with any one gear of the plurality of drive gears 210. An exemplary implementation of how the drive gears and the driven gears are selected for the transmission of torque may be explained in detailed in subsequent embodiments.

[0022] The operation of the varying the torque prior to the transmission of the power to the gearbox is now described. Also, the operation may be performed when the engine 202 is not running. Further, based on the load, the driver may select of the gear ratios. For example, in case of high load, the driver may select first gear ratio. In order to select the first ratio, the driver may operate the handle 108 to operate the lever 216. As the lever 216 actuates, the lever 216 moves the first driven gear 214-1 along the primary shaft 212 to engage with the first drive gear 210-1. Once the first drive gear 210-1 and first driven gear 214-1 have engaged, the lever 216 may be locked by a locking mechanism to ensure the first drive gear 210-1 and first driven gear 214-1 remains in engagement with each other. Once the locking mechanism is engaged, the driver may crank the engine 202 to run the engine 202. Now, as the engine 202 runs and the engine shaft 208 rotates, the first drive gear 210-1 and the first driven gear 214-1. The first drive gear 210-1 and the first driven gear 214-1 may amplify the torque from the engine shaft 208 to the primary shaft 212. The primary shaft 212 coupled to the gearbox 206 may now transmit the amplified torque to the gearbox 206 that may transfer the power to the wheels.

[0023] Now, in case of low load or travel on a levelled terrain, the lever 216 is configured to disengage the locking mechanism, for example, in one embodiment, by operating the handle 108. In this case, the lever 216 may be operated to first disengage the first drive gear 210-1 and first driven gear 214-1 and subsequently engages with second drive gear 210-2 and second driven gear 214-2. Thereafter, the lever 216 is secured in new position by the locking mechanism and t h e engine 202 is started. In this case, the power is transmitted from the engine shaft 208 to the primary shaft 212 through second drive gear 210- 2 and second driven gear 214-2. Further in an embodiment, each stage of speed transmission gears of the gearbox 206 is adapted to change the torque received from the primary shaft 212 based on the corresponding gear ratio of the stage of the speed transmission gears. Therefore, in case, the gearbox 206 has five stages of speed transmission gears, the primary shaft assembly 204 provides 10 different torque and speed (i.e., each stage with a high torque or a low torque received from the primary shaft 212). Thus, in an implementation, the primary shaft assembly 204 of the present subject matter is capable of doubling the transmission range. Thus, the primary shaft assembly 204 of the present subject matter is configured to achieve multiple gear ratios with no substantial modification to the layout of the vehicle 100. [0024] Although embodiments of the vehicle 100 have been described in the language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features are disclosed and explained in the context of a few embodiments of the vehicle 100.