DESC:GEARBOX ASSEMBLY FOR ELECTRIC VEHICLE
CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims priority from Indian Provisional Patent Application No. 202421002164 filed on 11/01/2024, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
Generally, the present disclosure relates to a transmission unit of an electric vehicle. Particularly, the present disclosure relates to a gearbox assembly for an electric vehicle.
BACKGROUND
The gearbox stands as a fundamental component in the functionality of any road-running vehicle, as it holds the pivotal responsibility of adjusting the power transmission ratio between the power source and the load, based on the vehicle speed. The adjustment of the transmission ratio is paramount for ensuring seamless vehicle operation and optimizing energy efficiency. Gearboxes are employed in diverse forms and designs, ranging from manual and automatic to Continuous Variable Transmission (CVT) systems. The absence of a gearbox leaves any vehicle incomplete, compromising its overall performance and efficiency.
Conventionally, gear bearings are placed between gears for smooth and efficient power transmission within a gear assembly. The bearings are positioned to support the intermediate gears located between a set of drive gears and a set of driven gears mounted on at least one gear shaft. The primary function of the bearings is to absorb the radial and axial loads generated as the gears mesh and rotate along the gear shaft. Further, the bearings maintain the alignment of the intermediate gears to prevent any lateral or sideways movement, which leads to inefficient power transfer, gear slippage, or misalignment of the gear teeth and gear shaft. The gears rotation generates friction and thereby reduces the efficiency of power transfer between gears. However, the bearings between the gears minimize the friction by creating a smooth, lubricated interface between the rotating components. Therefore, the bearings allow the gears to rotate with less resistance and thereby reduce the amount of energy lost to friction.
However, there are certain problems associated with the existing or above-mentioned mechanism of power transfer in the gear-box assembly of vehicles. For instance, the bearings positioned between the gears are not able to reduce the stress generated at the ends of the gear shaft which results in the bending of the gear shaft. Consequently, the power transfer between the drive gears and the driven gears is inefficient. Further, the bending of the gear shaft results in premature bearing failure, improper meshing of the gears, and the degradation of the overall gear-assembly performance, especially in high-precision applications.
Therefore, there exists a need for a power transfer mechanism in the gear-box assembly of vehicles that is efficient, safe, and overcomes one or more problems as mentioned above.
SUMMARY
An object of the present disclosure is to provide a gear-box assembly of an electric vehicle.
Another object of the present disclosure is to provide a gear-box assembly with a pair of bearings for smooth gear engagement and to mechanically support at least one gear shaft.
In accordance with an aspect of the present disclosure, there is provided a gear-box assembly of an electric vehicle, the gear-box assembly comprises:
- a plurality of drive gears mounted on a main shaft ;
- a plurality of driven gears mounted on a counter shaft ;
- a pair of main shaft bearings for supporting the main shaft; and
- a pair of counter shaft bearings for supporting the counter shaft,
wherein a first main shaft bearing from the pair of main shaft bearings is disposed in close proximity of a highest drive gear, and a first counter shaft bearing from the pair of counter shaft bearings is disposed in close proximity of a highest driven gear.
The gear-box assembly of an electric vehicle, as described in the present disclosure, is advantageous in terms of providing a gear-box assembly with enhanced efficiency and safety. Beneficially, the positioning of a pair of bearings in close proximity to a highest gear and a lowest gear ensures that the load on the gear shafts is evenly distributed and the friction generated between the gears is reduced. Consequently, the possibility of the misalignment of the gear shafts is lowered, resulting in smoother gear engagement and reduced wear over time, thereby contributing to more reliable performance of the gear-box assembly.
Additional aspects, advantages, features, and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments constructed in conjunction with the appended claims that follow.
It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
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.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
Figure 1 illustrates a detailed view of a gear-box assembly of an electric vehicle, in accordance with an embodiment of the present disclosure.
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
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 recognize that other embodiments for carrying out or practicing the present disclosure are also possible.
As used herein, the terms “gear-box assembly” and “assembly” are used interchangeably and refer to a mechanical component that transfers power from the motor to the wheels, allowing the vehicle to operate efficiently at various speeds and conditions. The gear-box assembly consists of a set of gears housed in a protective casing working together to adjust the rotational speed of the motor output, enabling the vehicle to operate efficiently across different conditions. The assembly consists of key components such as gears, shafts, bearings, and housing, all designed to handle the torque and power output from the electric motor while maintaining smooth and quiet operation. Therefore, the gearbox assembly plays a vital role in maximizing energy efficiency, enhancing the vehicle overall performance, and contributing to the longevity of the motor.
As used herein, the terms “electric vehicle”, “vehicle”, and “EV” are used interchangeably and refer to a vehicle that is driven by an electric motor that draws its electrical energy from a battery and is charged from an external source. The electric vehicle includes both a vehicle that is only driven by the electric motor that draws electrical energy from the battery (all-electric vehicle) and a vehicle that may be powered by an electric motor that draws electricity from the battery and by an internal combustion engine (hybrid vehicle). Moreover, the ‘electric vehicle’ as mentioned herein may include electric two-wheelers, electric three-wheelers, electric four-wheelers, electric trucks, electric pickup trucks, and so forth.
As used herein, the term “drive gears” refers to the set of gears that receive power from an external source and transmit the generated rotational force to driven gears within the gearbox assembly. The drive gears are mounted on a shaft and serve as the starting point for the transfer of mechanical energy in the gear assembly. The drive gear rotation causes the meshing driven gears to rotate which in turn transmits the power throughout the gear assembly. The size and tooth configuration of the drive gear determines the gear ratio, which affects the output speed and torque of the system. The drive gears play a key role in the overall function of mechanical systems such as transmissions, differential gearboxes, and other machinery. Specifically, the drive gears are the first link in a chain of gears that powers the machine output for the operation of the vehicle.
As used herein, the term “main shaft” refers to a central rotating component in a mechanical system of the vehicle drivetrain, that transmits power from the motor to other drive components of the vehicle. The main shaft is supported by bearings at both ends, allowing it to rotate freely with minimum friction and wear. The main shaft is connected to gears or linkages that alter the speed or torque to deliver the power to the wheels. In multi-gear systems, the main shaft serves as the central hub that interacts with other shafts or gear sets to provide a range of speed options. Therefore, the main shaft is a fundamental component in ensuring the reliability, efficiency, and longevity of the vehicle drivetrain.
As used herein, the term “driven gears” refers to the gears that receive rotational power from the drive gears and transmit it to the wheels of the vehicle. The driven gear teeth mesh with the drive gear teeth, allowing the power generated by the motor to be transferred through the gear train. The driven gear is smaller or larger than the drive gear, depending on the desired output speed and torque. The role of driven gears is crucial in adjusting the mechanical output of the system, whether by increasing or decreasing speed, or altering the torque applied to a component, such as a wheel or another shaft. The driven gears are of various types, such as (but not limited to) spur gears, helical gears, or planetary gears, each serving specific purposes in power transmission. The durability and precise meshing of driven gears are critical for ensuring the smooth operation of the entire gear system, and any malfunction or misalignment may lead to inefficient power transfer or mechanical failure.
As used herein, the term “counter shaft” refers to a secondary shaft that works in coordination with the main shaft to transmit power and manage the distribution of torque. The gears mounted on the counter shaft mesh with the gears of the main shaft to adjust the speed and torque delivered to the wheels. The counter shaft rotates in the opposite direction of the main shaft and achieves the desired gearing ratios, that allow the vehicle to operate at different speeds or under varying load conditions. Consequently, the counter shaft is able to modify the rotational force from the motor and thereby optimizes the power output and efficiency of the drivetrain.
As used herein, the term “main shaft bearing” refers to a component that supports the main shaft, allowing it to rotate smoothly with minimum friction and wear. The main shaft bearings are designed to withstand the axial and radial loads generated by the rotation of the main shaft, ensuring that the shaft remains aligned and operates efficiently. Further, the main shaft bearings provide a low-friction surface ensuring that heat generated during the vehicle operation is reduced thereby helping to prolong the lifespan of both the shaft and surrounding components. Common bearing types include (but not limited to) ball bearings, roller bearings, or sleeve bearings, each offering different levels of load capacity, durability, and smoothness of operation.
As used herein, the term “counter shaft bearing” refers to a component that supports the counter shaft, allowing the counter shaft to rotate smoothly to minimize friction and prevent wear. The counter shaft bearings maintain the alignment of the counter shaft to transfer power and torque from the main shaft to other components. The counter shaft bearings are designed to handle both radial and axial loads generated by the rotating shaft, ensuring that the counter shaft operates efficiently by reducing friction under varying load conditions. The precise functioning of the counter shaft bearing is critical for the smooth operation of the vehicle and prevents excessive vibrations that may lead to premature wear or damage. The counter shaft bearing with precise construction ensures that the counter shaft remains properly aligned and rotates without minimal friction.
As used herein, the term “fork shaft” refers to a component that facilitates the engagement and disengagement of gears in the vehicle. The fork shaft is connected to the shift fork, which moves the gears along the transmission main shaft or countershaft to change the vehicle gear ratio. Consequently, as the shift fork moves along the fork shaft, the gears are pushed into position, enabling the selection of different gears in the gear assembly. The engagement and disengagement of gears allow the transmission to alter the power output and speed, based on the rider input. The fork shaft is mounted securely within the transmission case and provides the mechanical support for the shift fork to operate smoothly. The fork shaft ensures that the gears are aligned properly during shifting and manages the forces involved during gear engagement, preventing misalignment or damage.
As used herein, the term “shifter fork” refers to a component in a vehicle transmission system for moving gears in and out of engagement within the gearbox. The shifter fork is designed to slide along the shaft spline and push or pull the gears into appropriate positions based on the shifting of the gears. The shifter fork is connected to the shift mechanism via the fork shifter to interact with the gears and ensure the correct gear is selected for the vehicle speed or power requirements. The operation of the shifter fork is integral to smooth gear transitions and the overall functionality of the transmission. The shifter fork is paired with the shifter fork bearings to reduce friction and allow for smoother movement within the transmission housing.
As used herein, the term “drum cam gear shaft” refers to a component that is connected to a drum cam mechanism to engage or disengage gears depending on the rotational position of the counter shaft. The drum cam gear shaft interacts with other gear components to select the appropriate gear ratio based on the vehicle speed and power. The cam is a rotating cylindrical component with a series of grooves or splines that is engaged by the counter shaft, guiding the movement of other parts of the transmission system, and ensuring smooth and efficient gear changes. The drum cam gear shaft design and smoothness prevent slipping or jerking during gear shifts, as any malfunction disrupts the performance of the transmission.
In accordance with an aspect of the present disclosure, there is provided a gear-box assembly of an electric vehicle, the gear-box assembly comprises:
- a plurality of drive gears mounted on a main shaft ;
- a plurality of driven gears mounted on a counter shaft ;
- a pair of main shaft bearings for supporting the main shaft; and
- a pair of counter shaft bearings for supporting the counter shaft ,
wherein a first main shaft bearing from the pair of main shaft bearings is disposed in close proximity of a highest drive gear, and a first counter shaft bearing from the pair of counter shaft bearings is disposed in close proximity of a highest driven gear.
Referring to figure 1, in accordance with an embodiment, there is described a gear-box assembly 100 of an electric vehicle. The gear-box assembly 100 comprises a plurality of drive gears 102 mounted on a main shaft 104, a plurality of driven gears 106 mounted on a counter shaft 108, a pair of main shaft bearings 110 for supporting the main shaft 104, and a pair of counter shaft bearings 112 for supporting the counter shaft 108. Further, a first main shaft bearing 110A from the pair of main shaft bearings 110 is disposed in close proximity of a highest drive gear 114, and a first counter shaft bearing 112A from the pair of counter shaft bearings 112 is disposed in close proximity of a highest driven gear 116. Furthermore, a second main shaft bearing 110B is disposed in close proximity of a lowest drive gear 118. Furthermore, a second counter shaft bearing 112B is disposed in close proximity of a lowest driven gear 120. Furthermore, the gear-box assembly 100 comprises a fork shaft 122, a shifter fork 124, and a drum cam gear shaft 126.
The arrangement of bearings in the gearbox assembly 100 with the first main shaft bearing 110A positioned near the highest drive gear 114 and the first counter shaft bearing 112A near the highest driven gear 116, provides significant technical advantages in terms of load distribution and transmission efficiency. Specifically, positioning the bearings in close proximity to the critical gears, ensures that the main shaft 104 and counter shaft 108 are supported at the point of the highest torque and stress. Consequently, the risk of shaft misalignment or excessive deflection is reduced, ensuring proper engagement of the drive gears 102 and the driven gears 106. Further, the placement of the bearings reduces the impact of vibrations, ensuring smooth operation of the gearbox and thereby minimizing wear on the gears and bearings. Furthermore, the proximity of the bearings to the highest drive gear 114 and driven gears 116 helps reduce the amount of friction and thereby enables more efficient power transfer through the gears, as the shafts are better supported and able to rotate with minimal resistance. Additionally, with reduced wear on the bearings and shafts, the system is less prone to noise, rough shifting, or mechanical failure, leading to a more reliable and smoother transmission experience. This design enhances the overall longevity of the gearbox, reducing maintenance needs and improving the efficiency of the vehicle drivetrain.
In an embodiment, a second main shaft bearing 110B is disposed in close proximity of a lowest drive gear 118. The placement of the second main shaft bearing 110B close to the lowest drive gear 118 is advantageous in terms of stability, load distribution, and the overall efficiency of the transmission system. Specifically, the positioning of the second main shaft bearing 110B near the lowest drive gear 118, mechanically supports the main shaft 104 more effectively at critical points of highest torque and forces that are experienced during the vehicle operation. The close proximity ensures that the second main shaft bearing 110B directly absorbs and stabilizes the loads generated by the gear, thereby reducing stress on the main shaft 104 and the surrounding transmission unit components. Consequently, the main shaft 104 deflections or misalignment is minimized, ensuring smoother gear engagement and reducing wear over time thereby contributing to more reliable performance. The close placement allows for better management of radial and axial loads, reducing the chances of premature failure or excessive vibration. Additionally, supporting the main shaft 104 at a crucial point, the second main shaft bearing 110B improves the overall efficiency of power transfer through the transmission. The above-mentioned design also reduces the potential for noise and friction, leading to a quieter and more refined operation.
In an embodiment, a second counter shaft bearing 112B is disposed in close proximity of a lowest driven gear 120. The lowest driven gear 120 is subjected to high torque and load during the vehicle operation, and placing a bearing nearby ensures that the load is distributed evenly. Consequently, the counter shaft 108 is stabilized and thereby prevents excessive deflection or misalignment of the counter shaft 108. Further, the placement in the close proximity of the second counter shaft bearing 112B ensures smooth rotation and efficient power transfer between the gears, enhancing the overall performance of the transmission system. Furthermore, the second counter shaft bearing 112B improves the durability and reliability of the drivetrain as the risk of gear slippage, abnormal wear, or noise caused by insufficient support is minimized. Therefore, the above-mentioned bearing arrangement enhances the longevity, efficiency, and smoothness of the vehicle transmission, improving the overall driving experience and reducing the need for frequent maintenance.
In an embodiment, the gear-box assembly 100 comprises a fork shaft 122, a shifter fork 124 and a drum cam gear shaft 126.
In an embodiment, the shifter fork 124 is mounted on the fork shaft 122. The mounting of the shifter fork 124 on the fork shaft 122 creates a stable and efficient mechanism for shifting gears within the transmission system. Advantageously, the fork shaft 122 acts as a central pivot point, allowing the shifter fork to move smoothly along the fork shaft axis and engage or disengage the gears. Further, securing the shifter fork 124 to the fork shaft 122 ensures precise and consistent movement of the shifter fork 124, enabling accurate gear selection. Therefore, the above-mentioned arrangement reduces the misalignment or shifting errors, contributing to the overall reliability and functionality of the transmission system.
In an embodiment, the shifter fork 124 is mechanically engaged with the plurality of drive gears 102. The mechanical engagement of the shifter fork 122 with the plurality of drive gears 102 ensures precise and reliable gear engagement within the transmission system. The shifter fork 124 moves the selected drive gear into the desired position, either engaging or disengaging with the rest of the drivetrain. Consequently, the mechanical connection between the shifter fork 124 and multiple gears allows for seamless shifts between different gear ratios thereby improving the overall performance and responsiveness of the vehicle. Further, the engagement with the plurality of drive gears 102 ensures that each drive gear is fully engaged, preventing partial engagement that leads to inefficient power transfer, slippage, or damage to the drive gears 102.
In an embodiment, the drum cam gear shaft 126 is mechanically engaged with the shifter fork 124 to control the plurality of driven gears 106. Advantageously, the drum cam gear shaft 126 rotation ensures that the cam profile interacts with the shifter fork 124, thereby guiding the shifter fork 124 movement along the drum cam gear shift 126 rails to engage or disengage the driven gear. Consequently, the above-mentioned precise interaction ensures that the gears are smoothly and accurately selected, allowing the transmission to seamlessly transition between different gear ratios. Further, the drum cam gear shaft 126 design enables efficient power distribution as only the desired gear is engaged at any given time, preventing potential damage from improper gear engagement. Therefore, the drum cam gear shaft 126 controlled movement of the shifter fork 124 reduces gear slippage, misalignment, or missed shifts. Additionally, the mechanical engagement ensures that power is transferred efficiently through the system, longevity of the transmission unit components, optimizing the performance of the vehicle and thereby contributing to a smoother, more controlled riding experience.
Based on the above-mentioned embodiments, the present disclosure provides significant advantages such as (but not limited to) load on the gear shafts being evenly distributed, the friction generated is reduced, misalignment of the gear shafts is lowered, smoother gear engagement, and thereby, more reliable performance of the gear-box assembly.
In the description of the present invention, it is also to be noted that, unless otherwise explicitly specified or limited, the terms “disposed,” “mounted,” and “connected” are to be construed broadly, and may for example be fixedly connected, detachably connected, or integrally connected, either mechanically or electrically. They may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Modifications to embodiments and combinations of different 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”, and “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.
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.
,CLAIMS:WE CLAIM:
1. A gear-box assembly (100) of an electric vehicle, the gear-box (100) assembly comprises:
- a plurality of drive gears (102) mounted on a main shaft (104);
- a plurality of driven gears (106) mounted on a counter shaft (108);
- a pair of main shaft bearings (110) for supporting the main shaft (104); and
- a pair of counter shaft bearings (112) for supporting the counter shaft (108),
wherein a first main shaft bearing (110A) from the pair of main shaft bearings (110) is disposed in close proximity of a highest drive gear (114), and a first counter shaft bearing (112A) from the pair of counter shaft bearings (112) is disposed in close proximity of a highest driven gear (116).

2. The gear-box assembly (100) as claimed in claim 1, wherein a second main shaft bearing (110B) is disposed in close proximity of a lowest drive gear (118).

3. The gear-box assembly (100) as claimed in claim 1, wherein a second counter shaft bearing (112B) is disposed in close proximity of a lowest driven gear (120).

4. The gear-box assembly (100) as claimed in claim 1, wherein the gear-box assembly (100) comprises a fork shaft (122), a shifter fork (124) and a drum cam gear shaft (126).

5. The gear-box assembly (100) as claimed in claim 4, wherein the shifter fork (124) is mounted on the fork shaft (122).

6. The gear-box assembly (100) as claimed in claim 4, wherein the shifter fork (124) is mechanically engaged with the plurality of drive gears (102).

7. The gear-box assembly (100) as claimed in claim 4, wherein the drum cam gear shaft (126) is mechanically engaged with the shifter fork (124) to control the plurality of driven gears (106).