DESC:POWER TRANSMISSION SYSTEM INCLUDING GEAR-BOX FOR ELECTRIC VEHICLES

CROSS REFERENCE TO RELATED APPLICATIONS:
[01] The present application claims priority from Indian Provisional Patent Application No. 202221013210 filed on 11th March 2022, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD:
[02] Generally, the present disclosure relates to a power transmission system for an electric vehicle (EV). In particular, the present disclosure relates to a power transmission system including a manual gearbox which transmits mechanical energy from a driving motor to a load of the electric vehicle.
BACKGROUND:
[03] The electric vehicle(s) (EVs) are currently experiencing a growing demand due to growing lack of fossil fuels and due to carbon dioxide emissions from exhaust in conventional internal engine vehicles. The EVs purely utilize an electric driving motor which runs on electric energy stored in the battery to power an electric vehicle.
[04] Currently, the EVs, specifically, the electric wheelers (EVs) utilize a single motor to drive the vehicle and require a heavy weight. This single heavy motor generates high inertia which causes a lag in transferring mechanical energy to wheels of the electric vehicle. Further, the single heavy motor is not able to optimize the battery consumption.
[05] Further, in conventional EVs, the driving motor is mounted directly on a hub of a rear wheel or is coupled to the rear wheel using an auxiliary transmission unit and a sprocket that drives the rear wheel. The auxiliary transmission unit includes a fixed gear ratio. The driving motor is only meant for altering the vehicle speed & wheel force of the electric vehicle. This arrangement limits the flexibility to the rider for varying the riding traction and vehicle speed.
[06] Thus, there exists a need of a multistage gearbox in the EVs to which enables the power transmission system to provide higher speed and higher torque to the load of the electric vehicle by minimizing power transmission losses.
SUMMARY:
[07] An object of the present disclosure is to provide a power transmission system including the gearbox which enables the power transmission system to provide higher speed and higher torque to the load of the electric vehicle by minimizing power transmission losses.
[08] Another object of the present disclosure is to provide a power transmission system including a gear-box that improves overall efficiency of the electric vehicle by maintaining the driving motor in higher efficiency range.
[09] Another object of the present disclosure is to provide a power transmission system including a gear-box that enables the power transmission system to provide higher speed and higher torque to the load of the electric vehicle by reducing weight of the power transmission system.
[010] Other objects and advantages of the system of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of present disclosure.
[011] The present disclosure overcomes one or more shortcomings of the prior art and provides additional advantages discussed throughout the present disclosure.
[012] In an aspect of the present disclosure, there is provided a power transmission system for electric vehicles including a gearbox, in accordance with a non-limiting embodiment of the present disclosure. The gearbox includes an engagement element adapted to engage the gearbox to a motor shaft and transmit rotary motion to a main shaft through an idler shaft, the main shaft is configured to transmit a torque to a driving sprocket through a counter shaft, and the driving sprocket is mounted on a free end of the counter shaft.
[013] The system, as disclosed in the present disclosure, is advantageous in terms of providing higher rotational speed and higher rotational torque to the load of the electric vehicle by minimizing power transmission losses. Further, the system, as disclosed in the present disclosure, improves overall efficiency of the electric vehicle by maintaining the driving motor in higher efficiency range. Furthermore, the system, as disclosed in the present disclosure, enables the power transmission system to provide higher speed and higher torque to the load of the electric vehicle by reducing weight of the power transmission system.
[014] Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS:
[015] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
[016] Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
[017] FIG. 1 illustrates a block diagram of a powertrain system of the electric vehicle, in accordance with an embodiment of the present disclosure.
[018] FIG. 2 illustrates a perspective view of a frame assembly, in accordance with an embodiment of the present disclosure.
[019] FIG. 3 illustrates a perspective view of the power transmission system, in accordance with an embodiment of the present disclosure.
[020] FIG. 4 illustrates a perspective view of a gearbox, in accordance with an embodiment of the present disclosure.
[021] Common reference numerals are used throughout the drawings and the detailed description to indicate the same elements.
[022] In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
DETAILED DESCRIPTION:
[023] The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognise that the other embodiments for carrying out or practicing the present disclosure are also possible.
[024] The detailed description set forth below in connection with the appended drawings is intended as a description of certain embodiments for a power transmission system including the gearbox and is not intended to represent the only forms that may be developed or utilized. The description sets forth the various structures and/or functions in connection with the illustrated embodiments; however, it is to be understood that the disclosed embodiments are merely exemplary of the present disclosure that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present disclosure.
[025] While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
[026] The terms “comprises”, “comprising”, “include(s)”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, system that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or system or method. In other words, one or more elements in a system or apparatus preceded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
[027] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
[028] The present invention will be described herein below with reference to the accompanying drawings. In the following description, well known functions or constructions are not described in detail since they would obscure the description with unnecessary detail.
[029] Referring to attached drawings, embodiments of the present disclosure will be described below. “front”, “rear”, “right”, “left”, “upper” and “lower” denote each position of a vehicle viewed from a rider. The drawings shall be viewed with regard to the reference numbers.
[030] The present disclosure describes a power transmission system for the electric vehicles to deliver power from a motor (a drive motor of an electric vehicle) to drive wheels or load of the vehicle which enables driving the electric vehicle.
[031] Fig. 1 is a powertrain system 100 of an electric vehicle (not shown in Fig. 1). The powertrain system 100 includes a power transmission system 102 and a load 104. The power transmission system 102 includes a driving motor 106 and a gearbox 108. The driving motor 106 includes a motor shaft (not shown in Fig. 1). The driving motor 106 is connected with the gearbox 108 by using the motor shaft. The load 104 of the electric vehicle is connected with the power transmission system 102. The driving motor 102 receives electrical energy from a power generator of an electric vehicle.
[032] The powertrain system 100 includes one or more power sources. The one or more power source may be configured to provide drive power, system and/or subsystem power, accessory power, and so forth. The one or more power source provides power to the driving motor 102 of the powertrain system 100.
[033] The gearbox 108 is a mechanical device used to increase the output torque or to change the speed of a driving motor 106. The shaft of the motor is connected to one end of the gearbox 108 and through the internal configuration of gears of a gearbox 108, gearbox 108 provides a given output torque and speed determined by the gear ratio.
[034] The driving motor 106 drives a motor shaft to rotate by using the received power from the power source. The motor shaft in the driving motor 106 is a component that extrudes out from the driving motor 106. The purpose of the motor shaft is to convert energy from the driving motor 106 into an end use application. When no load is applied to the motor shaft, the motor shaft runs at its fastest speed for that voltage with near zero torque. When enough load is applied to the motor shaft, the motor shaft stops running and generates the maximum amount of torque for that voltage.
[035] The gearbox 108 that is engaged with the driving motor 106 receives mechanical energy when the motor shaft rotates. The gearbox 108 provides the received mechanical energy to the load 104.
[036] Fig. 2 is a frame assembly 200 of the electric vehicle. The frame assembly 200 is constituted by a gearbox 202, casing 204, and frame 206.
[037] In a non-limiting embodiment of the present disclosure, the gearbox 202 is enclosed within a casing 204 and mounted within a frame 206 of the electric vehicle.
[038] The casing 204 is the one which will hold mechanical components of a transmission. The casing 204 is a protective casing which surrounds the components of a gearbox 202 (same as the gearbox 108 of Fig. 1). The casing 204 provides physical protection and mechanical support for gearbox 202. Generally, it is manufactured from cast iron or cast aluminum, using the permanent mould casting methods or shell molding method.
[039] The frame 206 comprises a separate frame and body construction (i.e., body-on-frame construction), a unitary frame and body construction (i.e., a unibody construction), or any other construction defining the structure of the vehicle. The frame 206 is made from one or more materials including, but in no way limited to steel, titanium, aluminum, carbon fiber, plastic, polymers, etc., and/or combinations thereof. The frame 206 is formed, welded, fused, fastened, pressed, etc., combinations thereof, or otherwise shaped to define a physical structure and strength of the vehicle. In any event, the frame 206 may comprise one or more surfaces, connections, protrusions, cavities, mounting points, pads, tabs, slots, or other features that are configured to receive other components that make up the vehicle. For example, the body panels, powertrain, controls system, interior components, and/or safety elements may interconnect with, or attach to, the frame 206 of the vehicle. The main criteria for the development of electric vehicle frame 206 are rigidity, strength and cost elimination. The frame 206 is the most important part of an electric vehicle, representing safety and life. The frame 206 of the vehicle carries a considerable amount of weight.
[040] In a non-limiting embodiment of the present disclosure, the gearbox 202 is mounted to a portion of the electric vehicle via one or more attachment points. For instance, the gearbox 202 is interconnected with the frame 206 via a bolted connection, clamped connection, or other attachment. In one embodiment, the casing 204 of the gearbox 202 includes one or more features configured to provide a removable connection to the frame 206 of the vehicle. These features include one or more flanges, ledges, feet, pads, protrusions, bolt holes, apertures, studs, threaded holes, threaded rods, and/or combinations thereof. The fixed interconnection of the gearbox 202 with the frame allows power to be efficiently transmitted from the driving motor (such as the driving motor 106 of Fig. 1) through the gearbox to load (such as the load 104 of Fig. 1).
[041] As illustrated in Fig. 3, the power transmission system 300 (such as power transmission system 102 of Fig. 1) is constituted by a gearbox 302 (such as gearbox 202 of Fig. 1), an engagement element 304, a motor shaft 306 (such as the motor shaft 106 of Fig. 1), a main shaft 308, and an idler shaft 310, a driving sprocket 310, a counter shaft 314, a primary shaft 316, and so forth.
[042] In a non-limiting embodiment of the present disclosure, the gearbox 302 includes the engagement element 304 adapted to engage the gearbox 302 to the motor shaft 306. The engagement element 304 transmits rotary motion to the main shaft 308 through the idler shaft 306. The main shaft 308 transmits a torque to the driving sprocket 310 through the counter shaft 312. The driving sprocket 310 is mounted on a free end of the counter shaft 312.
[043] In a non-limiting embodiment of the present disclosure, the primary shaft 316 may engage with the motor shaft 306 via the engagement element 304 such that rotary motion of the motor shaft 306 is transmitted to the primary shaft 316.
[044] The engagement element 304 is a mechanical element which engages the primary shaft 316 and the motor shaft 306. The engagement element 304 is ridges or teeth on a primary shaft 316 that matches with grooves in the motor shaft 306. In particular, the female spline on a side of the motor shaft 306 includes a groove part and a male spline on a side of the primary side 316 includes a teeth part. To transfer the mechanical energy from the motor shaft 306 to the primary shaft 316, the tooth part on the primary shaft 316 is engaged with the groove part on the motor shaft 306.
[045] The motor shaft 306 receives the electrical energy from one or more power sources. After receiving the electrical energy from one or more power sources the motor shaft 306 rotates by using the electrical energy. The motor shaft 306 is attached to a primary shaft 316 by using an engagement element 304. As the motor shaft 306 rotates, the primary shaft 316 also rotates with a rotational power. Rotation of the motor shaft 306 provides transfer of the mechanical power from to the primary shaft 316. The engagement element provides transfer of the rotational energy to the primary shaft 316 which enables rotation of the primary shaft 316.
[046] The primary shaft 316 couples the motor shaft 306 and idler shaft 306. In particular, the motor shaft coupler 302 is between the motor shaft 108 and the idler shaft 306 while absorbing some degrees of misalignments and mounting errors between the two shafts. One end of the primary shaft 316 is attached with motor shaft 306 such that when the motor shaft 108 rotates primary shaft 316 also rotates with the same mechanical power. Other end of the primary shaft 316 is attached with the idler shaft 306 such that the idler shaft 306 is rotated with the mechanical energy when the primary shaft 316 rotates.
[047] The primary shaft 316 is attached with the idler shaft 310 by using mechanical arrangement. This mechanical arrangement allows the rotation of the idler shaft 306 when the primary shaft 316 rotates with the mechanical energy. The attachment of the primary shaft 316 with the idler shaft 310 provides torque multiplication which increases rotational torque at the idler shaft 310 and reduces rotational speed (i.e. revolution per minute (RPM)) at the idler side 310.
[048] The primary shaft 316 receives mechanical energy from the motor shaft 108 and rotates with the rotational power received from the motor shaft 306. The primary shaft 316 transfers the mechanical power to the idler shaft 306 by using the mechanical arrangement. This mechanical arrangement allows the rotation of the idler shaft 306 with high rotational torque and less rotational speed than the rotation torque and the rotational speed of primary shaft 316.
[049] The idler shaft 310 is attached with the main shaft 308 by using the mechanical arrangement. The mechanical arrangement between the idler shaft 310 and the main shaft 308 provides the movement of the main shaft 308 based on the movement of the idler shaft 310. The attachment of the idler shaft 310 with the main shaft 308 provides torque multiplication which increases rotational torque at the main shaft 308 and reduces the rotational speed at the main shaft 308. The torque multiplication and the RPM reduction from the primary shaft 316 to idler shaft 310 and from the idler shaft 310 to the main shaft 306 is a two-stage multiplication process. This two-stage multiplication process minimizes the weight of the gearbox 302 and also maintains a centre of gravity of the gearbox 302 close to the ground.
[050] The main shaft 308 receives the mechanical energy from the idler shaft 310 based on the mechanical arrangement between the idler shaft 310 and the main shaft 308. The main shaft 308 transfers the mechanical energy to the counter shaft 314. The counter shaft 314 is transmitting mechanical power from the idler shaft 310 to the counter shaft 314.
[051] The counter shaft 314 transfers the power received from the main shaft 308 to the driving sprocket 312. The counter shaft 314 rotates at different RPM and torque compared to the main shaft 308 based on the gear mechanism. The counter shaft 314 transfers the mechanical power to the driving sprocket 312.
[052] The driving sprocket 312 is rotating toothed wheels which are used to transmit power or convey materials by engaging with roller or conveyor chains. The driving sprocket 312 is used primarily in chain driven systems to transmit power or rotation to the load (i.e. wheels) of the vehicle. The driving sprocket 312 is attached with the counter shaft 314. The driving sprocket 312 transmits the mechanical power received from the counter shaft 312 to the load of the vehicle.
[053] The present disclosure discloses that the system 300 provides higher rotational speed and higher rotational torque to the load of the electric vehicle by minimizing power transmission losses Further, the system 300 improves overall efficiency of the electric vehicle by maintaining the driving motor 106 in higher efficiency range. Furthermore, the system 300 reduces stress induced on the driving motor (such as the driving motor 106 of Fig. 1) during driving of the vehicle. Furthermore, the system 300 enables the use of a lower capacity driving motor 106.
[054] Fig. 4 describes a detailed overview of Fig. 3. As illustrated in Fig. 4 gearbox 400 (such as gearbox 202 of Fig. 2) is constituted by a primary shaft 402 (such as the primary shaft 316 of Fig. 3), an idler shaft 404 (such as the idler shaft 310 of Fig. 3), a main shaft 406 (such as the main shaft 308 of Fig. 3), and a counter shaft 408 (such as the counter shaft 314 of Fig. 3), a driving sprocket 410 (such as the driving sprocket 310 of Fig. 3), and so forth.
[055] In a non-limiting embodiment of the present disclosure, the primary shaft 402 may comprise a gear adapted to engage with a gear of the idler shaft 404 such that rotary motion of the primary shaft 402 is transmitted to the idler shaft 404.
[056] The primary shaft 402 includes a gear 414. The gear 414 is fixed on the primary shaft 402 either through a mechanical process or through a mechanical arrangement. The gear 414 is used to transmit power from primary shaft 402 to the idler shaft 404. The amount of torque transmitted via gear 414 depends on the number of teeth and size of the gear 414. Higher the gear ratio, higher the rotational torque/acceleration and lesser the rotational speed.
[057] The primary shaft 402 further includes a plurality of bearings 418. The primary shaft 402 is coupled to the motor shaft 108 using the engagement element (such as the engagement element 302 of Fig. 3). The plurality of bearings 418 is attached on both sides of the primary shaft 402. The plurality of bearings 418 is, not limited to, a first bearing 418-a and a second bearing 418-b. The plurality of bearings 418 can be more than two bearings for the primary shaft 402. The plurality of bearings 418 may be, for example, rolling element bearings, ball bearings, roller bearings, plain bearings, fluid bearings, magnetic bearings, and so forth. When the rotary motion encounters, the plurality of bearings 418 is required to support the revolving part and reduce the friction.
[058] The primary shaft 402 receives the mechanical power from the motor shaft (such as the motor shaft 108 of Fig. 1) and rotates with the received mechanical power. The plurality of bearings 416 attached on both sides of the primary shaft 402 provides a support to the primary shaft 402 so that primary shaft 402 rotates freely with the received mechanical power. Further, the plurality of bearing 416 reduces the friction during the rotation of the primary shaft 402 to deliver maximum power to the idler shaft 406.
[059] In a non-limiting embodiment of the present disclosure, a gear of the idler shaft 404 may be adapted to engage with the main shaft 408 using a mechanical arrangement of the power transmission system (same as the power transmission system 300 of Fig. 3) such that rotary motion of the idler shaft 404 is transmitted to the main shaft 408.
[060] The idler shaft 404 includes a plurality of gears 418. The plurality of gears 418 is fixed on the idler shaft 404 either through a mechanical process or through mechanical arrangement. The plurality of gears 418 includes, not limited to, a first gear 418-a and a second gear 418-b.
[061] The first gear 418-a of the idler shaft 404 receives power from the primary shaft 402. Number of teeth present in the first gear 418-a is larger than a number of teeth present in the gear 414 of the primary shaft 402. The higher number of teeth of the first gear 418-a provides rotation of the first gear 418-a with a torque higher than the rotation torque of the gear 414.
[062] The second gear 418-b of the idler shaft 404 is placed adjacent to the first gear 418-a with a specific gap between them. Both the first gear 418-a and the second gear 418-b are placed in the idler shaft 404 in a way so that the first gear 418-a and the second gear 418-b are at a specific distance from each other. The second gear 418-b receives the mechanical power from the first gear 418-a and transmits the mechanical power to a gear 432 of the clutch 406. The specific distance between the first gear 418-a and the second gear 418-b enables the gearbox 400 to transmit the power to the load without distortion.
[063] The idler shaft 404 further includes a plurality of bearing 420 (same as the plurality of bearings 418 of the Fig. 4). The plurality of bearings 420 is attached on both sides of the idler shaft 404. The plurality of bearings 420 includes, not limited to, a first bearing 420-a and a second bearing 420-b. The plurality of bearings 420 can be more than two bearings for the idler shaft 404.
[064] The idler shaft 404 receives the mechanical power from the primary shaft 402 by using the first bearing 420-a. In particular, the primary shaft 402 rotates with a torque and a speed. As the primary shaft 402 rotates, the gear 414 also rotates with the torque and the speed same as the torque and the speed of the primary shaft 402. The gear 418-a that is attached to the gear 414 also rotates. The gear 418-a rotates with high torque and low speed than the torque and speed of the gear 414 as the size of the gear 418-a is larger than a size of the gear 414 and the number teeth present in the gear 418-a is larger than the number of teeth present in the gear 414. After the rotation of the gear 418-a with the modified torque and modified speed, the gear 418-b also rotates with torque and speed the same as the torque and speed of the gear 418-a.
[065] The gear 418-a and gear 418-b have a different number of teeth. In an alternative embodiment of the present disclosure, the gear 418-a and gear 418-b have the same number of teeth.
[066] The plurality of bearings 420 attached on the both side of the idler shaft 404 provides a support to the idler shaft 404 so that idler shaft 404 rotates freely with the received mechanical power. Further, the plurality of bearing 420 reduces the friction during the rotation of the idler shaft 404 to deliver maximum power to the gear 432.
[067] The clutch 406 in the gearbox 400 acts as a mechanical linkage between the idler shaft 404 and the main shaft 408 to control transfer of mechanical energy from the driving motor (such as the driving motor 106 of Fig. 1) to the load (such as the load 104 of Fig. 1) via the gearbox 400. The clutch 406 is engaging and disengaging with the main shaft 408 either by manually (by the vehicle's driver) or by automatically by the vehicle itself.
[068] The clutch 406 connects the two shafts so they may be locked together and spin at the same speed (engaged), locked together but spinning at different speeds (slipping), or unlocked and spinning at different speeds (disengaged). In a specific embodiment, the clutch used in the gear shift arrangement of the present disclosure is a multi-plate wet clutch and have a supply of oil to lubricate and cool the components.
[069] The clutch 406 includes the gear 432 that is coupled with the second gear 418-b and receives mechanical energy from the second gear 418-b. A number of teeth present in the gear 432 is larger than the number of teeth present in the second gear 418-b. The higher number of teeth of the gear 432 provides rotation of the gear 432 with a torque higher than the rotation torque of the second gear 418-b.
[070] The number of teeth present in the gear 414, the first gear 418-a, and the gear 432 are decided based on the teeth multiplication ratio/torque multiplication. The teeth multiplication ratio/torque multiplication ratio is decided based on the required result from the gearbox 400 during the assembly of the gearbox 400. The torque multiplication based on the two-stage multiplication process minimizes the weight of the gearbox 300 and also maintains the centre of gravity of the gearbox 300 close to the ground.
[071] In a non-limiting example of the present disclosure, if the teeth multiplication ratio is 4.2 and the ratio of the teeth present in the gear 414 is x, in the first gear 418-a is y, and in the gear 432 is z, then the multiplication of the ratio of x/y and the ratio of y/z is equal to the multiplication ratio 4.2. In order to satisfy the multiplication of the ratio of x/y and the ratio of y/z equals to the multiplication ratio 4.2, the ratio of the x/y and the ratio of y/z must be greater than 1.
[072] In a non-limiting embodiment of the present disclosure, clutch 406 is adapted to enclose one end of the main shaft 408.
[073] Further, the clutch 406 includes a first plate (not shown in Fig. 4) and a second plate (not shown in Fig. 4). The first plate is attached to a housing of the clutch 406 and the second plate is attached to the main shaft 408. A portion of the main shaft 408 is present in the housing of the clutch 406. The second plate of the clutch 406 is attached with the portion of the main shaft 408 which is present in the housing of the clutch 406. Further, the first plate is also attached with the gear 432.
[074] During the engagement of the clutch 406 with the main shaft 408, the first plate is attached with the second plate. As the gear 432 rotates during the engagement of the clutch 406 with the main shaft 408, the main shaft 408 also rotates with the rotation of the gear 432.
[075] During the disengagement of the clutch 406 with the main shaft 408, the first plate is separated with the second plate. As the gear 432 rotates during the disengagement of the clutch 406 with the main shaft 408, the main shaft 408 does not receive mechanical energy from the gear 432.
[076] In a non-limiting embodiment of the present invention, the clutch 406 is adapted for manual selection of one of the plurality of gears 422 of the main shaft 408.
[077] The manual operation on the clutch allows the disengagement of the clutch 406 with the main shaft 408. When the clutch is disengaged with the main shaft 408, a user applies an operation to select the gears of the plurality of gears 422.
[078] In a non-limiting embodiment of the present disclosure, the main shaft 408 comprises a plurality of gears 422. The plurality of gears 422 of the main shaft 408 selectable manually for engagement with at least one gear out of a plurality of gears 426 arranged on the counter shaft 410.
[079] The main shaft 408 includes a plurality of gears 422. The plurality of gears is fixed on the main shaft 408 either through a mechanical process or through a mechanical arrangement. The plurality of gears 422 is used to transmit the power from the main shaft 408 to the counter shaft 410. The plurality of gears 422 includes, not limited to, a first gear 422-a, a second gear 422-b, a third gear 422-c, and a fourth gear 422-d. The plurality of gears 422 in the main shaft 408 can be more than four gears. At least one gear of the plurality of gear 422 provides torque multiplication and remaining gears of the plurality of gear 422 provides RPM multiplication.
[080] In a non-limiting example of the embodiment of the present disclosure, the first gear 422-a and the second gear 422-b provide torque multiplication when the main shaft 408 rotates. The third gear 422-c and the fourth gear 422-d provide RPM multiplication when the main shaft 408 rotates.
[081] The main shaft 408 further includes a plurality of bearings 424 (same as the plurality of bearings 418 of the Fig. 4). The plurality of bearings 424 is attached on both sides of the main shaft 408. The plurality of bearings 424 includes, not limited to, a first bearing 424-a and a second bearing 424-b. The plurality of bearings 418 can be more than two bearings for the main shaft 408.
[082] The main shaft 408 receives the mechanical power from the idler shaft 404 via the gear 432 when the clutch 406 engages with the main shaft 408. In particular, the gear 432 rotates with a torque and a RPM. As the gear 432 rotates during the engagement of the main shaft 408 with the clutch 406, housing of the clutch 406 also rotates. This rotation of the housing allows rotation of the first plate. After the rotation of the first plate, the second plate that is engaged with the main shaft 404 also rotates. The rotation of the second plate enables the rotation of the main shaft 408 such that the plurality of gears 422 of the main shaft also rotates with the mechanical energy received from the gear 432.
[083] The counter shaft 410 includes a plurality of gears 426. The plurality of gears 426 are not directly engaged with the counter shaft 410. The plurality of gears 426 rotates freely around the counter shaft 410. The plurality of gears 422 is used to transmit the power from the main shaft 408 to the driving sprocket 412. The plurality of gears 426 includes, not limited to, a first gear 426-a, a second gear 426-b, a third gear 426-c, and a fourth gear 426-d. The first gear 426-a is engaged with the first gear 422-a. The second gear 426-b is engaged with the second gear 422-b. The third gear 426-c is engaged with the third gear 422-c. The fourth gear 426-d is engaged with the fourth gear 426-d. The plurality of gears 426 in the counter shaft 410 can be more than four gears. At least one gear of the plurality of gear 426 provides torque multiplication and remaining gears of the plurality of gear 426 provides RPM multiplication. In particular, a number of teeth present in the at least one gear of the plurality of gears 426 is higher than a number of teeth present in the gear the main shaft 404 which are engaged with the at least one gear. A number of teeth present in each of the plurality of gears 426 apart from the at least one gear is lower than a number of the teeth of the engaged gear.
[084] In a non-limiting example of the embodiment of the present disclosure, a number of teeth present in the first gear 426-a is higher than a number of teeth present in the first gear 422-a and a number of the teeth present in the second gear 426-b is higher than a number of teeth present in the second gear 422-b. Higher number of teeth of the first gear 426-a and the second gear 426-b provides torque multiplication. A number of teeth present in the third gear 426-c is less than a number of teeth present in the third gear 422-c and a number of the teeth present in the fourth gear 426-d is less than a number of teeth present in the fourth gear 422-d. Lower number of teeth of the third gear 426-c and fourth gear 426-d provides RPM multiplication.
[085] The counter shaft 410 further includes a plurality of bearings 428 (same as the plurality of bearings 418 of the Fig. 4). The plurality of bearings 428 is attached on both sides of the counter shaft 410. The plurality of bearings 428 includes, not limited to, a first bearing 428-a and a second bearing 428-b. The plurality of bearings 428 can be more than two bearings for the counter shaft 410.
[086] The counter shaft 410 further includes a plurality of gear selectors 430 that engages with one of the plurality of gears 426 during the disengagement of the main shaft 408 with the clutch 406. The plurality of gear selectors 430 is attached on the counter shaft 410. The plurality of gear selectors 430 moves in the traverse direction of a length of the counter shaft 410. One of plurality of gear selectors 430 engages with one of the plurality of gears 426 either by the manual operation or by automatic operation on the plurality of gear selectors 430. One gear selector of the plurality gear selectors 430 engages with the one of the plurality of gears 426 and rotates with a torque and a RPM same as the torque and the RPM of the engaged gear. The rotation of the gear selector enables the rotation of the counter shaft 410.
[087] The driving sprocket 408 that is attached to the counter shaft 410 also rotates when the counter shaft rotates with the torque and the RPM of the engaged gear. The rotation of the driving sprocket 408 allows the driving sprocket 412 to transmit the mechanical power to the wheels of the vehicle.
[088] The present disclosure discloses that the system 400 provides higher rotational speed and higher rotational torque to the load of the electric vehicle by minimizing power transmission losses Further, the system 400 improves overall efficiency of the electric vehicle by maintaining the driving motor 106 in higher efficiency range. Furthermore, the system 400 reduces stress induced on the driving motor (such as the driving motor 106 of Fig. 1) during driving of the vehicle. Furthermore, the system 400 enables the use of a lower capacity driving motor 106.
[089] The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that ongoing technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.
[090] As will be appreciated by one skilled in the art, the present disclosure may be embodied as a system. Accordingly, the present disclosure may take the form of an entirely hardware embodiment and hardware aspects that may all generally be referred to herein as a “circuit,” “module,” or “system.” As used herein, the terms ‘power transmission system’, transmission system, ‘power transmission’ and ‘transmission’ are used interchangeably and refer to a combination of a gear-box, an electric motor, a rotary electric unit which transmits power through the gearbox, and a clutch which is provided between the input shaft and the output shaft of said gearbox to control the torque between the input shaft and the output shaft. The power transmission system may further include, but not limited to, differential, live axle and so forth.
[091] As used herein, the terms ‘gear-box’, ‘gear-shift’ and ‘gear-shift arrangement’ are used interchangeably and refer to a combination of a set of gears and their casing, connected to a clutch. Further, when in operation, the gear-box is operable to control the torque between the input shaft and the output shaft.
[092] Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating”, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural where appropriate.
[093] Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the present disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

WE CLAIM:
1. A power transmission system (300) for electric vehicles including a gearbox (302), the gearbox (302) comprising:
an engagement element (304) adapted to engage the gearbox (302) to a motor shaft (306) and transmit rotary motion to a main shaft (308) through an idler shaft (310), wherein
the main shaft (308) is configured to transmit a torque to a driving sprocket (312) through a counter shaft (314), and
the driving sprocket (312) is mounted on a free end of the counter shaft (314).
2. The power transmission system (300) for electric vehicles as claimed in claim 1, wherein the power transmission system (300) includes a primary shaft (316) adapted to engage with the motor shaft (306) via the engagement element (304) such that rotary motion of the motor shaft (306) is transmitted to the primary shaft (316).
3. The power transmission system (300) for electric vehicles as claimed in claim 2, wherein the primary shaft (316) comprises a gear adapted to engage with a gear of the idler shaft (310) such that rotary motion of the primary shaft (316) is transmitted to the idler shaft (310).
4. The power transmission system (300) for electric vehicles as claimed in claim 1, wherein a gear of the idler shaft (310) is adapted to engage with the main shaft (308) using a mechanical arrangement of the power transmission system (300) such that rotary motion of the idler shaft (310) is transmitted to the main shaft (308).
5. The power transmission system (300) for electric vehicles as claimed in claim 1, wherein the main shaft (308) comprises a plurality of gears, and wherein each of the plurality of gears of the main shaft (308) selectable manually for engagement with at least one gear out of a plurality of gears arranged on the counter shaft (314).
6. The power transmission system (300) for electric vehicles as claimed in claim 5, the power transmission system (300) comprises a clutch being adapted for manual selection of one of the plurality of gears of the main shaft (308).
7. The power transmission system (300) for electric vehicles as claimed in claim 6, wherein the clutch is adapted to enclose one end of the main shaft (308).
8. The power transmission system (300) for electric vehicles as claimed in claim 1, wherein the gearbox (302) is enclosed within a casing and mounted within a frame of the electric vehicle.
ABSTRACT

POWER TRANSMISSION SYSTEM INCLUDING GEAR-BOX FOR ELECTRIC VEHICLES
The present invention describes a power transmission system (300) for electric vehicles including a gearbox (302). The gearbox (302) comprises an engagement element (304) engages the gearbox (302) to a motor shaft (306) and transmits rotary motion to a main shaft (308) through an idler shaft (310). The main shaft (308) transmits a torque to a driving sprocket (312) through a counter shaft (314). The driving sprocket (312) is mounted on a free end of the counter shaft (314).

FIG. 3
,CLAIMS:WE CLAIM:
1. A power transmission system (300) for electric vehicles including a gearbox (302), the gearbox (302) comprising:
an engagement element (304) adapted to engage the gearbox (302) to a motor shaft (306) and transmit rotary motion to a main shaft (308) through an idler shaft (310), wherein
the main shaft (308) is configured to transmit a torque to a driving sprocket (312) through a counter shaft (314), and
the driving sprocket (312) is mounted on a free end of the counter shaft (314).
2. The power transmission system (300) for electric vehicles as claimed in claim 1, wherein the power transmission system (300) includes a primary shaft (316) adapted to engage with the motor shaft (306) via the engagement element (304) such that rotary motion of the motor shaft (306) is transmitted to the primary shaft (316).
3. The power transmission system (300) for electric vehicles as claimed in claim 2, wherein the primary shaft (316) comprises a gear adapted to engage with a gear of the idler shaft (310) such that rotary motion of the primary shaft (316) is transmitted to the idler shaft (310).
4. The power transmission system (300) for electric vehicles as claimed in claim 1, wherein a gear of the idler shaft (310) is adapted to engage with the main shaft (308) using a mechanical arrangement of the power transmission system (300) such that rotary motion of the idler shaft (310) is transmitted to the main shaft (308).
5. The power transmission system (300) for electric vehicles as claimed in claim 1, wherein the main shaft (308) comprises a plurality of gears, and wherein each of the plurality of gears of the main shaft (308) selectable manually for engagement with at least one gear out of a plurality of gears arranged on the counter shaft (314).
6. The power transmission system (300) for electric vehicles as claimed in claim 5, the power transmission system (300) comprises a clutch being adapted for manual selection of one of the plurality of gears of the main shaft (308).
7. The power transmission system (300) for electric vehicles as claimed in claim 6, wherein the clutch is adapted to enclose one end of the main shaft (308).
8. The power transmission system (300) for electric vehicles as claimed in claim 1, wherein the gearbox (302) is enclosed within a casing and mounted within a frame of the electric vehicle.