DESC:POWERTRAIN UNIT FOR ELECTRIC VEHICLE
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority from Indian Provisional Patent Application No. 202421024548 filed on 27/03/2024, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
Generally, the present disclosure relates to a gearbox assembly of an electric vehicle.
BACKGROUND
The electric vehicle(s) (EVs) are currently experiencing a growing demand due to lack of fossil fuels and due to carbon dioxide emissions from exhaust in conventional internal engine vehicles. The electric vehicles purely utilize an electric driving motor which runs on electric energy stored in the battery to power an electric vehicle.
Nowadays, there has been a recent push to develop hybrid and fully electric consumer passenger vehicles. Hybrid vehicles, which combine an electric motor with a traditional engine, offer a transitional solution by providing fuel savings and reduced emissions without the range limitations of fully electric vehicles. The growing availability of charging networks, along with declining battery costs, further accelerates the adoption of EVs, positioning them as the future of sustainable transportation.
Generally, electric vehicles are simple and easily adaptable, but the electric vehicles are constrained by limitations in efficiency, flexibility, and performance, particularly at elevated speeds. The electric vehicle often utilizes a hub motors, where the electric motors are integrated directly into the wheels for transfer of power to wheels. The hub motor design eliminates the need for a traditional drivetrain, making the hub motor system simple, lightweight, and efficient. However, the hub motors have notable limitations, including increased unsprung mass (the weight added directly to the wheel), which negatively impacts vehicle handling and ride comfort. Additionally, the hub motors are prone to overheating and having lower torque. Moreover, the hub motor limiting the vehicle’s top speed, makes the hub motor unsuitable for high-performance or long-range vehicles. Furthermore, as EVs are evolving with time, the manufacturers adopting a mid-drive motor which are effectively operating with single-speed transmissions due to their ability to deliver an extensive torque range and efficient power transfer. Due to presence of mid-drive motors, the single-speed transmission system delivers better torque control and improving the vehicle handling. However, at high speeds, the single-speed transmissions forced the motor to operate at high RPMs which leads to significant reduction in efficiency and range of the electric vehicle. Moreover, in high-performance situations, the single-speed transmissions restrict the vehicle’s ability to achieve both optimal acceleration and efficient cruising. Furthermore, a multi-speed transmission system used in electric vehicles provides advantages including enhanced efficiency, improved performance, extended driving range with the help of gear shifting, and superior vehicle handling. Additionally, the gear shifting in a manual transmission of the multi-speed transmission system provides the flexibility to adjust gear ratios to deliver maximum torque for acceleration or optimal speed for top performance. Moreover, a clutch is use in manual transmission for smooth gear changes by temporarily disengaging the motor from the transmission. However, the clutch disengagement during gear shift interrupts the power flow from the motor to the transmission. Due to which, a temporary torque cutoff occurs that results in a momentary loss of power to the wheels. Also, the process of clutch disengagement during gear shifting leads to reduction in vehicle acceleration and may cause potential wear on the clutch components. Furthermore, in an automated manual transmission of multi-speed transmission system, the gears shifting system uses traditional hydraulic or electronic mechanisms to shift gears smoothly and manage the gear changes automatically based on driving conditions, without need for manual input from the driver. However, the hydraulic or electronic gear shifting systems may introduce delays in gear engagement or disengagement. Moreover, the shift delays may detract the smooth and responsive driving experience expected in high-performance EVs. Moreover, the traditional multi-speed transmissions with hydraulic or electronic systems may have more parts which increases the complexity and weight of transmission system that are prone to wear and requires frequent maintenance of vehicle. Also, the above problems significantly causes reduction in efficiency of vehicle.
Thus, there is a need to develop an improved transmission system that overcomes the one or more problems as set forth above.
SUMMARY
An object of the present disclosure is to provide a gearbox assembly of an electric vehicle.
In accordance with an aspect of the present disclosure, there is provided a gearbox assembly of an electric vehicle. The gearbox assembly comprises a drum comprising a driven gear, a clutch actuation unit configured to actuate and de-actuate the drum via the driven gear, and at least one gear shifter fork connected to the drum, wherein each gear shifter fork is configured to engage and/or disengage with a corresponding gear of the plurality of gears based on a movement of the driven gear.
The present disclosure discloses the gearbox assembly of an electric vehicle. The gearbox assembly of present disclosure is advantageous in terms of providing significantly enhanced performance, efficiency, and reliability of the drivetrain of the electric vehicle. Furthermore, the gearbox assembly of the present disclosure is advantageous in terms of providing smooth shifting of the gears. Furthermore, the gearbox assembly of the present disclosure is compact in size. Furthermore, the gearbox assembly of the present disclosure enables quicker shifting of the gears.
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 perspective view of a gearbox assembly of an electric vehicle, in accordance with an aspect 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.
The description set forth below in connection with the appended drawings is intended as a description of certain embodiments of a clutch assembly 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 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 invention.
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.
The terms “comprise”, “comprises”, “comprising”, “include(s)”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, or 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. 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.
In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings 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.
The present disclosure 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.
As used herein, the terms “electric motor”, and “motor” are used interchangeably and refer to electric motors capable of being implemented in an industrial or automobile application, such as on the work machine or other vehicle
As used herein, the terms “transmission unit”, “transmission”, “multispeed gearbox” and “gearbox” are used interchangeably and refer to a mechanical device that manages the power delivered from a source to another part (like wheels). The transmission unit comprises transmission gears with different gear ratios to determine how the rotation speed and the torque are altered between input and output of the transmission unit.
As used herein, the terms “electric vehicle”, “EV”, and “EVs” are used interchangeably and refer to any vehicle having stored electrical energy, including the vehicle capable of being charged from an external electrical power source. This may include vehicles having batteries which are exclusively charged from an external power source, as well as hybrid-vehicles which may include batteries capable of being at least partially recharged via an external power source. Additionally, it is to be understood that the ‘electric vehicle’ as used herein includes electric two-wheeler, electric three-wheeler, electric four-wheeler, electric pickup trucks, electric trucks and so forth.
As used herein, the term “clutch actuation unit” refers to a mechanical or electromechanical system designed to engage or disengage a clutch mechanism within a vehicle's transmission system. The clutch actuation unit facilitates the transfer of power from the motor to the drivetrain by controlling the connection between the motor and the transmission. The clutch actuation unit typically includes components such as an actuator (which may be hydraulic, pneumatic, or electric), sensors to monitor the clutch status, and control logic to determine when to activate or deactivate the clutch based on operational conditions and driver inputs. The clutch actuation unit ensures smooth and precise clutch engagement and disengagement, enhancing vehicle performance, efficiency, and driver comfort.
As used herein, the term “drum” refers to a cylindrical component within a transmission system that serves as a housing for the clutch assembly. The drum typically receives rotational input from the motor and transmits this motion to the output shaft when the clutch is engaged. The drum enables controlled engagement and disengagement of power transfer based on the driver's input.
As used herein, the term “plurality of gears” refers to a set or group of two or more gears that are configured to work together within a mechanical system. The plurality of gears may vary in size, shape, and function, and are designed to transmit torque and rotational motion from one component to another. The plurality of gears may include different types of gears, such as spur gears, bevel gears, or planetary gears, which are arranged in a manner that optimizes the efficiency and effectiveness of the gear train.
As used herein, the term “gear shifter fork” refers to a mechanical component utilized in a transmission system to facilitate the engagement and disengagement of gears within a gearbox. The gear shifter fork comprises a bifurcated structure designed to slide along a shaft or within a selector mechanism, effectively guiding the movement of the associated gear slider or collar. The gear shifter fork is typically connected to a shifter mechanism and operates in conjunction with the transmission's control system, allowing the driver to select different gear ratios as needed. The gear shifter fork is crucial for ensuring smooth transitions between gears, enabling efficient power transfer from the motor to the drivetrain.
As used herein, the term “neutral position” refers to a specific state in which the power transmission between the motor and the driven wheels is disengaged. In neutral position, the output shaft is decoupled from the input shaft, allowing the driven wheels to rotate freely without being affected by the motor torque. This state is typically achieved through a mechanical or electronic system that prevents power flow, facilitating conditions such as stationary vehicle operation, safe towing, or motor idling without propulsion. The neutral position is an essential feature in various vehicle transmission systems, allowing for operational flexibility and safety during vehicle handling.
As used herein, the term “helical gear” refers to a type of gear characterized by its teeth, which are cut at an angle to the axis of rotation, forming a helical shape. The helical design of the helical gear allows for smoother engagement between meshing gears, resulting in reduced noise, vibration, and wear compared to straight-cut gears. In a drivetrain, helical gears transmit power and motion between shafts that are parallel or at an angle to each other, facilitating efficient torque transfer and improving the overall performance of the system. The helical arrangement of the teeth also enables the distribution of load over multiple teeth in contact, enhancing strength and durability.
As used herein, the term “spur gear” refers to a mechanical component characterized by straight teeth that are parallel to the gear's axis of rotation. In the drivetrain, spur gears are used to transmit torque and rotational motion between parallel shafts with high efficiency and minimal backlash. The spur gears mesh with one another to create a direct transfer of power, making them suitable for a wide range of applications in mechanical systems. Due to simple design of spur gear and ease of manufacturing, spur gears are commonly employed in various automotive and industrial applications, contributing to the overall performance and reliability of the drivetrain system.
As used herein, the term “dog clutch” refers to a mechanical device used in drivetrain systems to engage or disengage power transmission between two shafts, typically without the use of synchronizing mechanisms. The dog clutch consists of a pair of interlocking, tapered teeth (or "dogs") that are positioned on the ends of two components, allowing them to lock together when aligned. When engaged, the dog clutch transmits torque from one shaft to another, enabling the desired drivetrain function. The design of the dog clutch facilitates quick engagement and disengagement, making it ideal for applications that require frequent changes in power flow or direction, such as in manual transmissions, transfer cases, and some racing applications.
As used herein, the term “electronic control unit” refers to an electronic module configured to monitor, manage, and regulate various operational parameters of the battery or energy storage system. The control unit is responsible for processing input data, such as temperature, voltage, current, and state of charge, received from sensors or module management units. Based on the processed data, the control unit executes control algorithms to optimize the performance and safety of the system. This includes adjusting charging and discharging currents, activating current limiters, balancing cell voltages, detecting faults, and implementing fault recovery protocols to ensure reliable and efficient battery operation. Optionally, the control unit includes, but is not limited to, a microprocessor, a micro-controller, a complex instruction set computing (CISC) microprocessor, a reduced instruction set (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, or any other type of processing circuit. Furthermore, the term “processor” may refer to one or more individual processors, processing devices and various elements associated with a processing device that may be shared by other processing devices. Furthermore, the control unit may comprise ARM Cortex-M series processors, such as the Cortex-M4 or Cortex-M7, or any similar processor designed to handle real-time tasks with high performance and low power consumption. Furthermore, the control unit may comprise custom and/or proprietary processors.
As used herein, the term “clutch assembly” refers to a component responsible for smoothly connecting and disconnecting the motor’s power to the transmission unit. It may act as a bridge between the motor and the wheels.
As used herein, the term “drivetrain” refers to the complete system in a vehicle that transmits power from the motor or motor to the wheels, enabling motion. The drivetrain typically includes components such as the transmission, driveshaft, differential, axles, and any associated linkages and couplings. The drivetrain is critical for converting the motor’s output into usable torque and rotational energy, facilitating vehicle propulsion. It may encompass both mechanical and electrical elements, particularly in hybrid and electric vehicles, and is designed to optimize efficiency, performance, and reliability while accommodating various driving conditions.
Figure 1, in accordance with an embodiment describes perspective view of a gearbox assembly 100 of an electric vehicle. The gearbox assembly 100 comprises a drum 102 comprising a driven gear 106, a clutch actuation unit 104 configured to actuate and de-actuate the drum 102 via the driven gear 106, and at least one gear shifter fork 108 connected to the drum 102, wherein each gear shifter fork 108 is configured to engage and/or disengage with a corresponding gear of the plurality of gears 110 based on a movement of the driven gear 106.
The present disclosure discloses the gearbox assembly 100 of an electric vehicle. The gearbox assembly 100 of present disclosure is advantageous in terms of providing significantly enhanced performance, efficiency, and reliability of the drivetrain of the electric vehicle. Furthermore, the gearbox assembly 100 of the present disclosure is advantageous in terms of providing smooth shifting of the gears. Furthermore, the gearbox assembly 100 of the present disclosure is compact in size. Furthermore, the gearbox assembly 100 of the present disclosure enables quicker shifting of the gears.
In an embodiment, the gearbox assembly 100 is a multispeed gearbox assembly having a neutral position and the plurality gears 110. Beneficially, the multispeed gearbox configuration allows the vehicle to achieve various speeds and torque outputs effectively by enabling the driver or an automatic system to shift between gears as required for optimal performance. The presence of a neutral position enhances the versatility of the gearbox, providing a disengaged state where the motor may run without transmitting power to the wheels, which is particularly useful during idling or when the vehicle is stationary.
In an embodiment, the plurality of gears 110 are at least one of a star gear, a helical gear or a spur gear. The star gear is a lobate, star-shaped gear wheel used as a variable gear. The star gear may be used as a variable gear that is capable of transmitting power and motion with varying ratios. The helical gears are characterized by the angled teeth, which engage gradually and allow for smoother and quieter operation compared to traditional gears. Moreover, spur gears feature straight teeth and are ideal for transmitting power between parallel shafts, providing a straightforward and efficient means of motion transfer.
In an embodiment, the plurality of gears 110 are either fixed on a shaft 112 or free-wheeling on the shaft 112. When the gears are fixed, the gears rotate in unison with the shaft, ensures that the rotational motion is directly transmitted through the gear system, thereby enhancing torque delivery and mechanical efficiency. Conversely, when the gears are free-wheeling, the gears may rotate independently of the shaft, allowing for greater flexibility in speed adjustments and load distribution within the system. Beneficially, the gear configuration provides versatility in gear operation, thereby enables the system to adapt to varying operational requirements, such as changing load conditions.
In an embodiment, the gearbox assembly 100 comprises a dog clutch 114, and wherein the gear shifter fork 108 is configured to slide the dog clutch 114 to engage and/or disengage the corresponding gears 110. The design includes a gear shifter fork 108 specifically configured to slide the dog clutch 114 along the axis. When the gear shifter fork 108 is actuated, the gear shifter fork 108 translates the dog clutch 114 into the desired position which effectively engages or disengaging the plurality of gears 110. Beneficially, the mechanism allows for seamless transitions between gear states, thereby optimizing the power transfer between the motor and the drivetrain. Furthermore, the dog clutch 114 design provides a robust locking mechanism that minimizes slippage during engagement of clutches, thereby enhancing the overall reliability and performance of the clutch assembly 100.
In an embodiment, the dog clutch 114 is independent of the plurality of gears 110. Beneficially, the independent configuration of dog clutch 114 allows the dog clutch 114 to engage or disengage with the plurality of gears 110 without directly affecting the operational state of the gears, thereby providing enhanced control over the transmission system. Moreover, by enabling the dog clutch 114 to function autonomously, the system may selectively transmit torque between various components, thereby facilitating smooth transitions between different drive modes or gear selections.
In an embodiment, the drum 102 comprises a plurality of cam profiles or a plurality of helical profiles configured to translate rotational motion into linear motion for shifting the plurality of gears 110 by sliding the dog clutch 114. The mechanism facilitates the shifting of the plurality of gears 110 through the sliding action of the dog clutch 114. As the clutch drum rotates, the engagement of the cam or helical profiles generates a linear force that moves the dog clutch laterally, effectively engaging or disengaging specific gears within the gear system. Beneficially, the drum 102 allows for precise gear shifting, improving the responsiveness and overall efficiency of the transmission system of electric vehicle.
In an embodiment, the clutch actuation unit 104 is configured to receive shifting instruction from a user of the electric vehicle. The clutch actuation unit 104 interprets the user's input, which may come from a manual or automated interface, such as a gear lever or a digital display, to determine the desired gear selection. Upon receiving the shifting instruction, the clutch actuation unit 104 engages or disengages the dog clutch 114, accordingly, facilitating smooth transitions between gears 110.
In an embodiment, the clutch actuation unit 104 is configured to receive shifting instruction from an electronic control unit of the electric vehicle. The clutch actuation unit 104 interprets the ECU’s input, to determine the desired gear selection. Upon receiving the shifting instruction, the clutch actuation unit 104 engages or disengages the dog clutch 114, accordingly, facilitating smooth transitions between gears 110. Beneficially, such implementation enables automatic transmission.
In an embodiment, the clutch actuation unit 104 is a hydraulic, pneumatic, or electric actuator. Beneficially, the flexibility of utilizing hydraulic, pneumatic, or electric actuators in clutch assembly 100 enhances the system's versatility and integration within modern electric vehicles, thereby the overall efficiency and performance of electric vehicle is increased.
In an embodiment, the gearbox assembly 100 comprises the drum 102 comprising the driven gear 106, the clutch actuation unit 104 configured to actuate and de-actuate the drum 102 via the driven gear 106, and the at least one gear shifter fork 108 connected to the drum 102, wherein each gear shifter fork 108 is configured to engage and/or disengage with the corresponding gear of the plurality of gears 110 based on the movement of the driven gear 106. Furthermore, the gearbox assembly 100 is the multispeed gearbox assembly having the neutral position and the plurality gears 110. Furthermore, the plurality of gears 110 are at least one of the star gear, the helical gear or the spur gear. Furthermore, the plurality of gears 110 are either fixed on the shaft 112 or free-wheeling on the shaft 112. Furthermore, the gearbox assembly 100 comprises the dog clutch 114, and wherein the gear shifter fork 108 is configured to slide the dog clutch 114 to engage and/or disengage the corresponding gears 110. Furthermore, the dog clutch 114 is independent of the plurality of gears 110. Furthermore, the drum 102 comprises the plurality of cam profiles or the plurality of helical profiles configured to translate rotational motion into linear motion for shifting the plurality of gears 110 by sliding the dog clutch 114. Furthermore, the clutch actuation unit 104 is configured to receive shifting instruction from the user of the electric vehicle. Furthermore, the clutch actuation unit 104 is configured to receive shifting instruction from the electronic control unit of the electric vehicle. Furthermore, the clutch actuation unit 104 is the hydraulic, pneumatic, or electric actuator.
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 combination 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”, “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 gearbox assembly (100) of an electric vehicle, wherein the gearbox assembly (100) comprises:
- a drum (102) comprising a driven gear (106);
- a clutch actuation unit (104) configured to actuate and de-actuate the drum (102) via the driven gear (106); and
- at least one gear shifter fork (108) connected to the drum (102), wherein each gear shifter fork (108) is configured to engage and/or disengage with a corresponding gear of the plurality of gears (110) based on a movement of the driven gear (106).
2. The gearbox assembly (100) as claimed in claim 1, wherein the gearbox assembly (100) is a multispeed gearbox assembly having a neutral position and the plurality gears (110).
3. The gearbox assembly (100) as claimed in claim 2, wherein the plurality of gears (110) are at least one of: a star gear, a helical gear or a spur gear.
4. The gearbox assembly (100) as claimed in claim 3, wherein the plurality of gears (110) are either fixed on a shaft (112) or free-wheeling on the shaft (112).
5. The gearbox assembly (100) as claimed in claim 1, wherein the gearbox assembly (100) comprises a dog clutch (114), and wherein the gear shifter fork (108) is configured to slide the dog clutch (114) to engage and/or disengage the corresponding gears (110).
6. The gearbox assembly (100) as claimed in claim 5, wherein the dog clutch (114) is independent of the plurality of gears (110).
7. The gearbox assembly (100) as claimed in claim 1, wherein the drum (102) comprises a plurality of cam profiles or a plurality of helical profiles configured to translate rotational motion into linear motion for shifting the plurality of gears (110) by sliding the dog clutch (114).
8. The gearbox assembly (100) as claimed in claim 1, wherein the clutch actuation unit (104) is configured to receive shifting instruction from a user of the electric vehicle.
9. The gearbox assembly (100) as claimed in claim 1, wherein the clutch actuation unit (104) is configured to receive shifting instruction from an electronic control unit of the electric vehicle.
10. The gearbox assembly (100) as claimed in claim 1, wherein the clutch actuation unit (104) is a hydraulic, pneumatic, or electric actuator.