DESC:POWER TRAIN ASSEMBLY FOR AN ELECTRIC VEHICLE
CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims priority from Indian Provisional Patent Application No. 202321087084 filed on 20/12/2023, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
Generally, the present disclosure relates to a power train assembly for an electric vehicle(s). Particularly, the present disclosure relates to a motor shaft and a gear primary drive integration.
BACKGROUND
The demand for electric vehicles (EVs) is increasing due to the scarcity of fossil fuels and carbon dioxide emissions produced by traditional internal combustion engine vehicles. EVs operate solely on electric motors powered by energy stored in batteries, making them a more environmentally friendly alternative.
The motor is supplied with power from the battery pack to produce a rotational force which is further transferred to the wheels of the vehicle. The motor produces instant torque output and, hence, provides high acceleration for the vehicle. However, due to instantaneous high-power output, the battery efficiency of the vehicle is reduced. Consequently, the electric power stored in the battery pack of the electric vehicle is not efficiently delivered to the wheels of the electric vehicle. Therefore, transmission systems have been introduced for efficient power delivery of power to the wheels of the electric vehicles. The transmission system mechanically optimizes the power being delivered to the wheels of the electric vehicle, leading to better range of the vehicle and enhanced control over the power of the vehicle. The torque generated by the motor is transferred to the gearbox via a gear primary drive. Generally, the gear primary drive is mounted on a motor shaft via a spline located at the gear hub portion. The existing spline manufacturing process in the gear hub involves rolling or extrusion, which is essential for the efficient mounting of the gear primary drive on the motor shaft.
However, there are certain underlining problems associated with the above-mentioned existing mechanism of transferring the motor power to the wheels of the electric vehicle. For instance, the spline manufacturing process of rolling or extrusion results in higher runout contributions. The runout refers to misalignment due to manufacturing tolerances, thermal expansion, or uneven loading conditions. The runout may lead to vibrations or instability, which affects the overall performance of the transmission unit. Consequently, the misalignment results in uneven wear on the splines and gear teeth, potentially leading to premature failure of the components. Therefore, ensuring precise alignment and robust support is important for maintaining the reliability and longevity of the transmission unit.
Therefore, there exists a need for a mechanism for transferring the motor power to the wheels of the electric vehicle that is efficient, safe, and overcomes one or more problems as mentioned above.
SUMMARY
An object of the present disclosure is to provide a transmission unit of a powertrain assembly of an electric vehicle.
Yet another object of the present disclosure is to provide a transmission unit of a powertrain assembly of an electric vehicle, with improved efficiency and safety.
In accordance with an aspect of the present disclosure, there is provided a transmission unit of a powertrain assembly of an electric vehicle, wherein the transmission unit comprises:
- a motor shaft;
- a clutch assembly configured to couple and decouple an input shaft of the transmission unit with the motor shaft; and
- a gear primary drive comprising a gear hub for mounting the gear primary drive on the motor shaft.
The transmission unit of a powertrain assembly of an electric vehicle, as described in the present disclosure, is advantageous in terms of providing a transmission unit with less complex construction yet enhanced control of torque transfer from the motor to the wheels of the electric vehicle. Advantageously, the transmission unit provides a dual spline configuration of a gear hub that ensures the enhanced mechanical integrity and performance efficiency of the electric vehicle powertrain assembly. Further, the configuration of a clutch assembly and an input shaft enables smooth acceleration and deceleration of the vehicle and minimizes energy loss during idle periods.
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 an exploded view of a transmission unit of a powertrain assembly of an electric vehicle, in accordance with an embodiment of the present disclosure.
Figures 2a and 2b illustrate different views of a gear primary drive mounted on a motor shaft, in accordance with different embodiments 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 “transmission unit”, and “transmission assembly” are used interchangeably and refer to a component of an electric vehicle that manages the transfer of power from the electric motor to the wheels. Many EVs incorporate a single-speed transmission that allows the electric motor to deliver consistent torque and power across a wide range of speeds. Further, the transmission unit facilitates energy efficiency optimization and boosts overall vehicle performance. Additionally, some advanced EVs may employ a multi-speed transmission to further improve responsiveness and adaptability to different driving conditions. Overall, the transmission unit is essential for ensuring a smooth driving experience, maximizing the electric motor capabilities, and contributing to the vehicle's overall efficiency and performance.
As used herein, the term “powertrain assembly” refers to a comprehensive unit that includes all components for generating, managing, and delivering electrical power for the movement of the electric vehicle. The powertrain assembly comprises an electric motor, a battery pack, a transmission unit, and power electronics circuitry. The electric motor converts electrical energy from the battery into mechanical energy. The battery pack stores the mechanical energy, and the transmission unit transfers power to the wheels. Further, the power electronics circuitry controls energy flow, including inverters that convert DC to AC. Additionally, many EVs feature regenerative braking systems that capture kinetic energy during braking to recharge the battery. Overall, the powertrain assembly ensures efficient performance, responsiveness, and optimal energy management for the electric vehicle.
As used herein, the term “motor shaft” refers to a cylindrical component that transmits mechanical power generated by the motor to the electric vehicle drivetrain. The motor shaft is connected to a rotor that produces rotational motion. Further, the motor shaft is made from high-strength materials to withstand the torque produced by the motor and to ensure durability under various operating conditions. The motor shaft incorporates features such as keyways or splines to facilitate secure connections to other drivetrain components, such as but not limited to gears or axles. Additionally, the motor shaft may include bearings that support its rotation, and minimizes friction and wear. In essence, the motor shaft plays a critical role in efficiently converting electrical energy into mechanical energy, facilitating the propulsion of the vehicle.
As used herein, the term “clutch assembly” refers to a component that facilitates the engagement and disengagement of the motor power to the drivetrain, allowing for smooth transitions between motion states. The clutch assembly comprises a pressure plate, clutch disc, and release mechanism, which work together to control the connection between the motor and the wheels. The clutch assembly, when engaged allows power to flow, enabling acceleration; when disengaged, it disconnects the motor from the drivetrain, facilitating deceleration or stopping without stalling the motor. The above functionality enhances driving comfort and responsiveness while contributing to overall vehicle performance.
As used herein, the terms “Gear Primary Drive”, and “GPD” are used interchangeably and refer to a component that facilitates the transfer of power from the electric motor to the wheels of the electric vehicle. The gear primary drive comprises a gear arrangement that converts the motor’s high-speed output into usable torque at lower speeds, thereby optimizing performance for various driving conditions. The gear arrangement is designed to balance performance and efficiency, allowing the vehicle to accelerate smoothly while maintaining energy efficiency during cruising. Depending on the design of the transmission unit, the GPD may feature a single-speed gear ratio or a multi-speed configuration, catering to different driving scenarios and enhancing the driving experience.
As used herein, the term “gear hub” refers to a component within the drivetrain that houses the gears that transmit power from the electric motor to the wheels of the electric vehicle. The gear hub serves as the central point for gear reduction, allowing the high-speed rotation of the motor to be converted into usable torque for acceleration and movement. The design of the gear hub is optimized for efficiency and durability, incorporating high-strength materials to withstand the stresses of operation while minimizing energy losses. Further, the gear hub integrates multiple gears and bearings to facilitate smooth operation and enhance performance. The arrangement of gears within the hub allows for precise control over the power delivery, which is essential for achieving optimal acceleration and speed characteristics. Depending on the vehicle's design, the gear hub may feature a single-speed setup for simplicity and efficiency or a multi-speed system that enables a wider range of performance options, catering to various driving conditions.
As used herein, the term “gear transmission drive” refers to a component designed to efficiently transfer power from the electric motor to the wheels of an electric vehicle. The gear transmission drive comprises a series of gears that convert the motor’s high rotational speed into the appropriate torque required for acceleration and sustained driving. Further, the gear ratios are engineered to optimize performance across various driving conditions, ensuring that the vehicle can accelerate smoothly while maintaining energy efficiency. Furthermore, the advanced designs may feature technologies such as electronic control systems that allow for real-time adjustments of gear ratios, thereby enhancing the driving experience. Therefore, the gear transmission drive translates the electric motor's capabilities into effective propulsion, contributing to the overall efficiency and responsiveness of the electric vehicle.
As used herein, the term “spline” refers to a series of ridges or grooves that are cut along the length of the shaft, designed to create a precise mechanical connection with another component, such as, but not limited to a gear, coupling, or another shaft. The spline allows for effective torque transmission while accommodating misalignment and ensuring that the connected components rotate together. Splines come in various forms, including external and internal splines, and are crucial for applications requiring high strength and reliability, particularly in automotive and industrial settings.
As used herein, the terms “Gear Primary Driven” and “GPDn” are used interchangeably and refer to a component that receives torque from the gear primary drive and transmits it to the subsequent stages of the drivetrain, thereby delivering power to the wheels. The gear primary driven typically meshes with the driving gears mounted on the input shaft, allowing for effective torque transfer. The design of the Gear Primary Driven is crucial for ensuring that the power generated by the electric motor is efficiently utilized, enabling the vehicle to accelerate smoothly and respond dynamically to driving conditions.
In accordance with an aspect of the present disclosure, there is provided a transmission unit of a powertrain assembly of an electric vehicle, wherein the transmission unit comprises:
- a motor shaft;
- a clutch assembly configured to couple and decouple an input shaft of the transmission unit with the motor shaft; and
- a gear primary drive comprising a gear hub for mounting the gear primary drive on the motor shaft.
Referring to figure 1, in accordance with an embodiment, there is described a transmission unit 100 of a powertrain assembly of an electric vehicle. The transmission unit 100 comprises a motor shaft 102, a clutch assembly 104 configured to couple and decouple an input shaft 106 of the transmission unit 100 with the motor shaft 102, and a gear primary drive 108 comprising a gear hub 110 for mounting the gear primary drive 108 on the motor shaft 102.
The clutch assembly 104 is configured to couple and decouple an input shaft 106 of the transmission unit 100 with the motor shaft 102. Advantageously, the coupling and decoupling ensures enhanced control over torque transfer, which enables smoother acceleration and deceleration of the vehicle. Additionally, the clutch assembly 104 engagement with the transmission unit 100 facilitates seamless gear shifting, reducing wear on components and extending the lifespan of the transmission system. Further, a gear hub 110 comprises a first spline 110a, and a second spline 110b. The first spline 110a is configured to provide radial support to the motor shaft 102, ensuring significant stability and alignment within the powertrain assembly. The radial support facilitates the proper positioning of the motor shaft 102 during the vehicle operation, thereby preventing vibrations and misalignment of the transmission unit components. Further, the effective management of the radial loads ensures that the motor 114 operates smoothly, and the vehicle stability is enhanced. Furthermore, the second spline 110b, designed to facilitate torque transfer from the gear primary drive 108 to the gear primary driven 120, enhances the efficiency of power transmission within the transmission unit 100. The second spline 110b allows for effective torque transfer while accommodating misalignments, thereby reducing stress concentrations on the transmission unit components. Therefore, the dual spline configuration of the gear hub 110 contributes to both the mechanical integrity and performance efficiency of the electric vehicle powertrain.
In an embodiment, the clutch assembly 104 is configured to facilitate interim coupling and decoupling of the input shaft 106 of the transmission unit 100 with the motor shaft 102. The interim coupling and decoupling of the input shaft 106 provide controlled and flexible engagement between the motor 114 and the transmission unit 100 during various operational states of the vehicle such as during gear shifting, idle states, or variable load conditions. Further, engagement or disengagement of the input shaft 106 and motor shaft 102 facilitates smooth gear changes in the transmission system of the vehicle. Advantageously, the smooth gear change minimizes abrupt jerks or shocks that occur during gears shifting and thereby, reduces the mechanical stress on the drivetrain and enhancing vehicle comfort.
In an embodiment, the transmission unit 100 comprises a gear transmission drive 112 mounted on the input shaft 106 to receive power output of a motor 114, via the motor shaft 102. The above-mentioned configuration allows for direct and efficient transfer of power from the motor 114 to the drivetrain, ensuring minimal energy loss during transmission. Further, mounting the gear transmission drive 112 on the input shaft 106, the transmission unit 100 optimizes torque conversion and speed reduction, allowing the vehicle to achieve the desired acceleration effectively. Moreover, the overall architecture of the powertrain is simplified, thereby reducing the weight and complexity of the transmission unit. Additionally, a dedicated gear transmission drive 112 allows for more precise control over gear ratios, enabling the vehicle to adapt quickly to varying driving conditions, such as steep inclines or rapid acceleration demands. Therefore, the above-mentioned transmission unit 100 enhances the electric vehicle's responsiveness, efficiency, and overall performance, leading to a safe driving experience.
In an embodiment, the gear transmission drive 112 is connected to the clutch assembly 104, via the input shaft 106. Beneficially, the gear transmission drive 112 is connected to the clutch assembly 104 allowing for seamless power transfer between the motor 114 and the drivetrain, enabling smooth engagement and disengagement of the clutch. As the input shaft 106 serves as a direct path for power, it facilitates rapid adjustments in torque delivery, thereby providing responsive acceleration and deceleration. The smooth operation contributes to improved energy efficiency by ensuring that more of the motor's output is effectively used for propulsion. Further, the above-mentioned connection minimizes the mechanical stress on both the clutch and transmission components, reducing wear and prolonging the lifespan. Further, aligning the gear transmission drive 112 and clutch assembly 104 through the input shaft 106 ensures efficient accommodation of different gear ratios, providing greater flexibility in tuning performance characteristics based on driving conditions.
In an embodiment, the transmission unit 100 comprises a central plate 116 configured to separate the clutch assembly 104 from the gear transmission drive. Advantageously, the separation allows for more effective thermal management within the powertrain. The clutch assembly 104 generates heat during engagement and disengagement with the gear components. The isolation of the clutch assembly 104 from the gear transmission drive 112 ensures that the central plate 116 prevents heat transfer to the gear components. Consequently, the risk of overheating is reduced which may degrade the performance and lifespan of the gears. Additionally, the central plate 116 enhances the structural integrity and rigidity of the transmission unit. Further, the central plate 116 acts as a robust partition, thereby minimizing vibrations and potential misalignment between the clutch and gear systems.
In an embodiment, the gear primary drive 108 is mounted on the motor shaft 102 and configured to deliver power output to a clutch drive shaft 118 of the clutch assembly 104. The gear primary drive 108 mounted on the motor shaft 102 facilitates a highly efficient power transfer system by ensuring a direct connection between the electric motor 114 and the clutch assembly 104, minimizing energy losses associated with intermediate gear components. Further, the alignment of the gear primary drive 108 with the motor shaft 102 ensures optimized torque output and speed reduction, allowing the vehicle to accelerate smoothly and responsively. Furthermore, the direct coupling ensures that the motor performance characteristics are effectively utilized, enhancing overall vehicle efficiency and responsiveness during vehicle operation.
Referring to figures 2a and 2b, illustrate different views of a gear primary drive 108 mounted on a motor shaft 102, in accordance with different embodiments, as described the gear primary drive 108 comprises a gear hub 110 including a first spline 110a and a second spline 110b. The first spline 110a is configured to provide radial support to the motor shaft 102 for ensuring significant stability and alignment within the powertrain assembly, and a second spline 110b configured to facilitate torque transfer from the gear primary drive 108 to gear primary driven 120 for enhancing the efficiency of power transmission within the transmission unit 100. The radial support facilitates the proper positioning of the motor shaft 102 during the vehicle operation, thereby preventing vibrations and misalignment of the transmission unit components. Further, the effective management of the radial loads ensures that the motor 114 operates smoothly, and the vehicle stability is enhanced. The stability contributes to the overall reliability and performance of the powertrain, allowing for consistent torque delivery and minimizing potential disruptions during the vehicle operation. The second spline 110b allows for effective torque transfer while accommodating misalignments, thereby reducing stress concentrations on the transmission unit 100 components. Furthermore, the second spline 110b arrangement optimizes the transfer of torque ensuring the electric motor 114 output is utilized effectively, thereby improving acceleration and responsiveness of the vehicle. Overall, the dual spline configuration of the gear hub 110 contributes to both the mechanical integrity and performance efficiency of the electric vehicle powertrain.
In an embodiment, the gear transmission drive 112, of the transmission unit 100, comprises an output shaft 122 configured to transfer torque received from the input shaft 106 to a spoke wheel 124 of the powertrain assembly. Advantageously, the output shaft 122 provides effective channeling of the torque received from the input shaft 102, ensuring that the power generated by the electric motor 114 is efficiently transmitted to the wheels. Consequently, the direct transfer of the power minimizes energy losses occurring due to friction or misalignment in the drivetrain, leading to improved acceleration and responsiveness. Furthermore, the design of the output shaft 122 is often optimized for strength and rigidity, allowing it to handle high torque loads without deformation, thereby maintaining consistent vehicle performance under varying driving conditions.
In an embodiment, the gear transmission drive 112 comprises a plurality of driving gears 126 mounted on the input shaft 106 and a plurality of driven gears 128 mounted on the output shaft 122. The plurality of driving gears 126 and the plurality of driven gears 128 allows for effective torque multiplication, enabling the motor 114 to deliver high torque at low speeds. Further, the distribution of the power across multiple gear pairs optimizes the torque transfer process, thereby reducing the gear slippage. Furthermore, the above-mentioned configuration enhances the overall reliability of the drivetrain by ensuring that loads are shared among several gears, thereby minimizing the stress on individual components. Additionally, the multiple driving and driven gears contribute to improved flexibility in gear ratios, allowing the transmission unit to adapt to varying driving conditions.
In an embodiment, the plurality of driving 126 and driven gears 128 are configured to transfer torque from the input shaft 106 to the output shaft 122. The multiple-gear pairs allow for an effective torque multiplication process that optimizes the acceleration and responsiveness in an electric vehicle. Further, each gear pair efficiently handles a portion of the overall load, reducing the risk of slippage or excessive wear on individual gears. Moreover, the multiple driving and driven gears enable a variety of gear ratios, allowing the transmission to adapt more easily to changing driving conditions. This flexibility is particularly beneficial in electric vehicles, where varying demands on power delivery, such as during acceleration, climbing hills, or navigating turns, require quick adjustments to torque and speed.
Based on the above-mentioned embodiments, the present disclosure provides significant advantages such as (but not limited to) enhanced control over torque transfer, improved mechanical integrity, smooth acceleration and deceleration of the vehicle, and thereby enhanced performance efficiency of the electric vehicle powertrain 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 transmission unit (100) of a powertrain assembly of an electric vehicle, wherein the transmission unit (100) comprises:
- a motor shaft (102);
- a clutch assembly (104) configured to couple and decouple an input shaft (106) of the transmission unit (100) with the motor shaft (102); and
- a gear primary drive (108) comprising a gear hub (110) for mounting the gear primary drive (108) on the motor shaft (102).

2. The transmission unit (100) as claimed in claim 1, wherein the transmission unit (100) comprises a gear transmission drive (112) mounted on the input shaft (106) to receive power output of a motor (114), via the motor shaft (102).

3. The transmission unit (100) as claimed in claim 1, wherein the gear transmission drive (112) is connected to the clutch assembly (104), via the input shaft (106).

4. The transmission unit (100) as claimed in claim 3, wherein the transmission unit comprises a central plate (116) configured to separate the clutch assembly (104) from the gear transmission drive (112).

5. The transmission unit (100) as claimed in claim 1, wherein the gear primary drive (108) is mounted on the motor shaft (102) and configured to deliver power output to a clutch drive shaft (118) of the clutch assembly (104).

6. The transmission unit (100) as claimed in claim 1, wherein the gear hub (110) comprises a first spline (110a) configured to provide radial support to the motor shaft (102), and a second spline (110b) configured to facilitate torque transfer from the gear primary drive (108) to gear primary driven (120).

7. The transmission unit (100) as claimed in claim 1, wherein the gear transmission drive (112), of the transmission unit (100), comprises an output shaft (122) configured to transfer torque received from the input shaft (106) to a spoke wheel (124) of the powertrain assembly.

8. The transmission unit (100) as claimed in claim 7, wherein the gear transmission drive (112) comprises a plurality of driving gears (126) mounted on the input shaft (106) and a plurality of driven gears (128) mounted on the output shaft (122).

9. The transmission unit (100) as claimed in claim 8, wherein the plurality of driving (126) and driven gears (128) are configured to transfer torque from the input shaft (106) to the output shaft (122).