DESC:MULTI-SPEED TRANSMISSION SYSTEM FOR ELECTRIC VEHICLES
CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims priority from Indian Provisional Patent Application No. 202421104577 filed on 30/12/2024, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
The present disclosure generally relates to an electric vehicle. Particularly, the present disclosure relates to a multi-speed transmission unit for an electric vehicle.
BACKGROUND
In recent decades, there has been a significant growth and technological advancement in the field of electric vehicles (EVs). The development of EVs has primarily focused on improving efficiency, performance, and sustainability. However, despite these advancements, several technical challenges continue to persist, particularly related to space constraints, vehicle gradeability, and overall weight optimization.
Conventionally, electric vehicles, such as three-wheelers, four-wheelers, buses, and trucks, are equipped with a single-speed fixed transmission system. The adoption of such a configuration is primarily aimed at reducing drivetrain mass, volume, power losses, and cost, thereby simplifying the vehicle architecture. These vehicles typically employ a Brushless Direct Current (BLDC) motor to deliver power to the transmission system. While the existing BLDC motor and single-speed transmission configuration enable satisfactory torque output at low speeds, allowing the vehicle to achieve adequate gradeability, this configuration limits the vehicle’s ability to attain higher top speeds. The torque-speed characteristic of the BLDC motor inherently results in a trade-off between high torque at low speed and high-speed performance.
To achieve both good gradeability and higher top speeds, the use of higher-capacity motors has been considered. However, integrating such motors and the associated components leads to increased vehicle weight and space requirements, which are undesirable from both design and performance standpoints. These challenges highlight the need for an improved drivetrain configuration that can deliver both high torque for gradeability and enhanced top-speed performance without significantly increasing the overall weight or space requirements of the vehicle.
Therefore, there exists a need for an improved transmission system that overcomes one or more problems associated as set forth above.
SUMMARY
An object of the present disclosure is to provide a multi-speed transmission unit for an electric vehicle.
In accordance with an aspect of the present disclosure, there is provided a multi-speed transmission unit for an electric vehicle. The transmission unit comprises a gear primary drive (GPD) mounted on a motor shaft and a gear primary driven (GPDn) mounted on a clutch shaft. The GPD and the GPDn are configured to achieve a contact ratio of two or more.
The present disclosure provides the multi-speed transmission unit for the electric vehicle. The multi-speed transmission unit as disclosed in present disclosure is advantageously ensures smoother power transfer, reduced noise, and enhanced durability due to improved load distribution across multiple gear teeth. Beneficially, the transmission system facilitates efficient torque transfer with minimal slippage, thereby enhancing transmission efficiency. Further, the transmission system ensures the operational flexibility and protection of drivetrain components under varying load conditions. Furthermore, the transmission system configuration provides an optimized gear ratio for balancing the torque and speed requirements, thereby contributing to improved vehicle performance in terms of gradeability and top speed. Moreover, the transmission system ensures the reliability under high torque loads. Overall, the transmission system provides a compact, efficient, and durable transmission solution, addressing the limitations of existing single-speed systems while maintaining favorable weight and space characteristics suitable for modern electric vehicles.
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:
FIG. 1 illustrates a side view of a GPD and a GPDn of a multi-speed transmission unit 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 recognise that other embodiments for carrying out or practising 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 multi-speed transmission unit for an electric vehicle and is not intended to represent the only forms that may be developed or utilised. 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 minimised 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.
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.
In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings, 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.
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 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 terms “multi-speed transmission unit” and “transmission unit” are used interchangeably and refer a mechanical assembly configured to transmit rotational power from a motor to a vehicle drivetrain at multiple selectable gear ratios. The transmission unit enables variation in torque and speed output in accordance with the operating requirements of the vehicle, thereby optimizing performance under different driving conditions such as acceleration, cruising, and climbing. The multi-speed transmission unit typically comprises a set of driving and driven gears, shafts, and shifting or clutch mechanisms that facilitate engagement and disengagement between different gear pairs to achieve the desired gear ratio. In the electric vehicles, the multi-speed transmission unit serves to enhance both gradeability (low-speed torque) and top-speed capability while maintaining compactness, reduced weight, and improved overall efficiency compared to single-speed systems.
As used herein, the terms “gear primary drive” and “gear drive” are used interchangeably and refer to a driving gear element mounted on a motor shaft and configured to transmit rotational motion and torque from the motor to a corresponding driven gear (gear primary driven). The gear primary drive serves as the input gear in a gear train of a transmission system and is designed to engage with the driven gear through meshing teeth to facilitate power transfer. The gear primary drive may include structural features such as a spline coupling, keyway, or hub portion to ensure secure engagement with the motor shaft and efficient torque transmission.
As used herein, the terms “gear primary driven” and “gear driven” are used interchangeably and refer to a driven gear component that is mechanically coupled to receive rotational motion from a corresponding gear primary drive mounted on a driving shaft, such as a motor shaft. The gear primary driven is typically mounted on a clutch shaft or an intermediate shaft and is configured to transmit the received torque to subsequent drivetrain components, such as a clutch mechanism or a main transmission shaft. The gear primary driven functions as the output member of the primary gear pair and plays a key role in determining the overall gear ratio, torque transmission efficiency, and power flow within the transmission unit.
As used herein, the term “motor shaft” refers to a rotatable member extending from the rotor of an electric motor and configured to transmit rotational power generated by the motor to a connected component, such as a gear, pulley, or transmission input element. The motor shaft serves as the primary mechanical interface between the motor and the drivetrain, converting electrical energy into mechanical torque for driving associated systems. The motor shaft may be supported by bearings, aligned along a rotational axis, and may include coupling features such as splines, keyways, or threads to facilitate secure engagement with other mechanical components.
As used herein, the term “clutch shaft” refers to a rotating shaft configured to transmit power from a driving component, such as a motor or an engine, to a driven component through a clutch mechanism. The clutch shaft typically serves as the input or intermediate shaft of the transmission system and is operatively connected to the clutch assembly to facilitate selective engagement and disengagement of torque transmission between the power source and the transmission. In an electric vehicle, the clutch shaft enables controlled transfer of rotational motion from the motor to the main transmission shaft, thereby allowing smooth shifting of gears and protection of drivetrain components during load variations.
As used herein, the term “contact ratio” refers to the average number of gear teeth that are simultaneously in contact between a driving gear and a driven gear during rotation. The contact ratio of two or more indicates that at least two pairs of teeth are engaged at any given instant, which ensures continuous transmission of torque, smoother operation, and reduced impact or vibration between gear teeth.
As used herein, the terms “inner square spline coupling” and “spline coupling” are used interchangeably and refer to a mechanical connection feature formed on the inner diameter of a gear, hub, or similar rotating component, comprising a series of equally spaced, square-shaped grooves or teeth that extend along the axial length of the component. The inner square spline is configured to engage with a corresponding external square-shaped shaft or projection, thereby creating a positive torque-transmitting connection between the two components. The so forth inner square spline coupling allows for precise rotational alignment and efficient transfer of torque from the driving shaft (e.g., motor shaft) to the driven component (e.g., gear) while accommodating slight axial movement or misalignment.
As used herein, the term “central hub portion” refers to the central, axially aligned segment of a gear, wheel, or rotary component that is configured to receive, support, or engage with a shaft, spindle, or other rotating element. The central hub portion typically provides a secure mechanical interface between the gear and the shaft, enabling torque transfer while maintaining proper alignment during rotation. Further, the central hub portion may include features such as splines, keyways, internal threads, or interference fits to facilitate coupling with the shaft and prevent relative motion between the gear and the shaft during operation. The central hub portion may also be designed to provide structural rigidity to the gear and to evenly distribute loads from the gear teeth to the shaft.
As used herein, the term “operatively coupled” refers to a configuration in which one component is connected to another component, either directly or indirectly, such that the components interact or cooperate to perform a specified function. The coupling may be mechanical, electrical, hydraulic, or otherwise, and enables the transmission of power, signals, or motion necessary for the operation of the system.
As used herein, the term “clutch mechanism” refers to a mechanical assembly configured to selectively engage or disengage the transmission of torque between an input shaft, such as a motor shaft, and an output shaft, such as a main or driven shaft of a transmission unit. The clutch mechanism is designed to control the transfer of power within the drivetrain, allowing the input shaft to be isolated from the output shaft when required, thereby preventing unwanted rotation, reducing load on the motor, and enabling smooth gear shifting. The clutch mechanism may include one or more friction plates, springs, or other torque-transmitting components arranged to facilitate controlled engagement, torque modulation, and disengagement of the drivetrain as per operational requirements of the electric vehicle.
As used herein, the term “gear ratio” refers to the ratio of the rotational speed of a driving gear (input gear) to the rotational speed of a driven gear (output gear) in a transmission system. More specifically, it is defined as the ratio of the number of teeth on the driven gear to the number of teeth on the driving gear. The gear ratio determines the mechanical advantage, torque multiplication, and speed reduction or increase between the input and output shafts of the transmission. A higher gear ratio provides greater torque at the output shaft while reducing rotational speed, whereas a lower gear ratio allows higher output speed with proportionally lower torque. In the transmission system, the gear ratio is selected and configured to optimize the balance between low-speed torque (for gradeability) and high-speed performance of the electric vehicle.
In accordance with an aspect of present disclosure, there is provided a multi-speed transmission unit for an electric vehicle, the transmission unit comprising:
- a gear primary drive (GPD) mounted on a motor shaft; and
- a gear primary driven (GPDn) mounted on a clutch shaft,
wherein the GPD and the GPDn are configured to achieve a contact ratio of two or more.
Figure 1, in accordance with an embodiment, describes a multi-speed transmission unit 100 for an electric vehicle. The transmission unit 100 comprising a gear primary drive (GPD) 102 mounted on a motor shaft and a gear primary driven (GPDn) 104 mounted on a clutch shaft. The GPD 102 and the GPDn 104 are configured to achieve a contact ratio of two or more.
In an embodiment, the GPD 102 may comprises an inner square spline coupling 106 configured to engage with the motor shaft for facilitating torque transfer. During assembly, the inner square spline of the GPD 102 is slid over the corresponding external square profile on the motor shaft, thereby establishing a positive mechanical connection between the motor and the transmission unit 100. When the motor operates, the rotational torque generated by the motor is transmitted directly through the spline coupling 106 to the GPD 102, ensuring synchronized rotation of the gear with the motor shaft. The so forth spline coupling 106 configuration allows for a compact and precise connection without the need for additional fasteners or couplings, facilitating ease of assembly and reliable operation under varying torque loads. Beneficially, the inclusion of the inner square spline coupling 106 in the GPD 102 provides efficient and direct transfer of torque from the motor to the transmission unit 100, thereby minimizing power losses typically associated with friction-based or loosely connected couplings. Further, the spline coupling 106 provides axial and radial stability, reducing the risk of gear misalignment and vibrations during operation, in turn enhances the durability and reliability of the transmission unit 100. Additionally, the positive engagement ensures the high torque loads, transmitting without slippage, enabling the electric vehicle to achieve both high gradeability at low speeds and sufficient top-speed performance. Furthermore, the compact nature of the spline coupling 106 helps in optimizing the overall space and weight of the transmission unit 100.
In an embodiment, the GPDn 104 may comprises a central hub portion 108 configured to couple with the clutch shaft. The central hub portion 108 is designed to ensure a secure and precise connection between the GPDn 104 and the clutch shaft, thereby facilitating efficient transmission of torque from the motor through the transmission unit 100 to the main drivetrain. The hub portion 108 may include features such as splines, keyways, or other engagement mechanisms to ensure axial alignment and rotational stability during operation. The so forth central hub portion 108 configuration allows the clutch mechanism to engage and disengage the input power from the motor without causing slippage or misalignment in the gear assembly, thereby maintaining smooth and reliable transmission operation. Beneficially, the inclusion of the central hub portion 108 on the GPDn 104 ensures precise coupling with the clutch shaft, enabling accurate torque transfer and reducing the risk of backlash or mechanical wear in the transmission. Further, the configuration allows for selective isolation of the motor from the drivetrain through the clutch mechanism, improving the operational flexibility, protects the motor and gears from overload, and facilitates smoother gear shifting. Furthermore, the central hub portion 108 contributes to the overall robustness and durability of the transmission unit 100, allowing the electric vehicle to achieve improved performance in both low-speed, high-torque conditions (gradeability) and higher-speed operations without compromising reliability or efficiency.
In an embodiment, the GPDn 104 may be operatively coupled to a clutch mechanism, the power is transferred to the main shaft through the clutch mechanism, and the clutch mechanism isolates the input shaft from the motor. The GPDn 104 transfers the torque to the clutch mechanism, selectively engages or disengages the input power to the main shaft. When the clutch mechanism is engaged, the main shaft receives power from the motor, allowing the vehicle to propel forward. Conversely, when the clutch mechanism is disengaged, the input shaft is isolated from the motor, thereby preventing torque transmission to the main shaft. The so forth arrangement allows controlled power flow within the transmission unit 100, enabling smooth start-stop operation, preventing drivetrain shock, and protecting the motor and associated components from sudden load changes. Beneficially, the incorporation of the clutch mechanism in the transmission unit 100 allows the selective isolation of the motor from the drivetrain, which enhances operational flexibility and safety during vehicle startup, stopping, or gear shifting. Further, the clutch mechanism minimizes mechanical stress on the gears and motor, reducing wear and improving overall durability of the transmission unit 100. Furthermore, the controlled engagement of power ensures smoother acceleration and deceleration, improving ride quality and energy efficiency.
In an embodiment, the GPD 102 comprises 51 teeth and the GPDn 104 comprises 104 teeth. The selection of the number of teeth on the GPD 102 and the GPDn 104 is configured to establish a specific gear ratio suitable for the torque and speed requirements of the electric vehicle. The higher tooth count on the GPDn 104 relative to the GPD 102 enables torque multiplication while maintaining efficient power transmission from the motor shaft to the clutch shaft. Beneficially, the increased number of teeth on the GPDn 104 contributes to a reduction in transmission noise and gear wear, ensuring smoother operation and longer service life. Further, the chosen combination of 51 and 104 teeth allows efficient utilization of motor torque without requiring a larger or heavier motor, thereby addressing space and weight constraints in electric vehicles.
In an embodiment, the GPD 102 and GPDn 104 are configured with a module of 1.5 and a pressure angle of 17.5°. The module of 1.5 determines the size and spacing of the gear teeth, ensuring an optimal balance between compactness and strength of the gear pair. Further, the selected pressure angle of 17.5° defines the angle between the line of action and the tangent to the pitch circle, thereby influencing the load distribution and smoothness of meshing between the GPD 102 and GPDn 104. The so forth specific combination of module and pressure angle allows the gears to transmit torque efficiently while maintaining low noise and vibration levels during operation. Beneficially, the module of 1.5 and the pressure angle of 17.5° enables precise and stable gear engagement, reducing mechanical losses and ensuring smooth torque transmission between the motor and clutch shafts. Further, the lower pressure angle minimizes radial loads on the gear shafts, thereby enhancing bearing life and reducing wear of the gear teeth. Furthermore, the compact tooth geometry resulting from the selected module contributes to a reduced overall transmission size, making the transmission unit 100 suitable for space-constrained electric vehicle applications. Additionally, the optimized tooth profile improves the contact ratio and distributes the load more evenly across the gear teeth, resulting in quieter operation, higher efficiency, and extended service life of the transmission unit 100.
In an embodiment, the GPD 102 and GPDn 104 may be configured together to provide a gear ratio of 2.039. The GPD 102 is mounted on the motor shaft and functions as the driving gear, while the GPDn 104 is mounted on the clutch shaft and functions as the driven gear. The selection of the number of teeth and the corresponding gear dimensions are optimized such that the rotational speed of the GPD 102 is reduced by a factor of 2.039 when transmitted to the GPDn 104. The so forth configuration enables the transmission unit 100 to effectively balance torque multiplication and speed reduction, thereby improving the overall performance characteristics of the electric vehicle drivetrain. Beneficially, the specific gear ratio of 2.039 provides a significant advantage by enhancing the torque output available at the clutch shaft without requiring a larger or heavier motor. The enhanced torque output enables improved gradeability, allowing the vehicle to climb slopes or carry heavy loads efficiently. Simultaneously, the optimized gear ratio ensures the motor speed is efficiently converted into usable wheel speed, maintaining desirable top-speed performance. Further, the configuration also contributes to better energy efficiency, as the motor operates closer to the optimal efficiency range during both acceleration and steady-state driving. Furthermore, by achieving the balance through gearing rather than motor upsizing, the gear design minimizes space constraints and reduces overall vehicle weight, leading to improved packaging flexibility and reduced drivetrain stress.
In an embodiment, the GPD 102 and GPDn 104 are made of hardened alloy steel. The hardened alloy steel provides superior mechanical strength and resistance to wear, deformation, and surface fatigue under continuous torque transmission. The gears are subjected to a hardening process, such as carburizing or induction hardening, to achieve a high surface hardness while maintaining a tough core, thereby ensuring both strength and durability. The use of hardened alloy steel allows the transmission unit 100 to sustain high torque loads and repetitive engagement cycles without significant material degradation, contributing to a longer operational life of the gear set.
The present disclosure provides the multi-speed transmission unit 100 for an electric vehicle. The multi-speed transmission unit 100 as disclosed by present disclosure is advantageous by incorporating the GPD 102 mounted on the motor shaft and the GPDn 104 mounted on the clutch shaft, the transmission unit 100 achieves the contact ratio of two or more, ensuring smoother torque transmission, reduced noise, and enhanced load-carrying capacity. Further, the higher contact ratio contributes to improved gear meshing characteristics, minimizing vibration and ensuring better durability of the transmission components. Furthermore, the inner square spline coupling 106 provided in the GPD 102 facilitates a positive and backlash-free torque transfer from the motor shaft, thereby enhancing efficiency and minimizing power losses. Similarly, the central hub portion 108 of the GPDn 104 ensures precise coupling with the clutch shaft, contributing to stable rotational alignment and effective torque transmission. Moreover, the operative coupling of the GPDn 104 with the clutch mechanism allows selective engagement and disengagement between the motor and the main shaft, enabling smooth gear shifting and protecting the drivetrain from sudden torque fluctuations. Moreover, the clutch mechanism also enables isolation of the motor from the drivetrain when required, improving energy efficiency and reducing mechanical wear. Subsequently, the specific gear tooth configuration, with the GPD 102 having 51 teeth and the GPDn 104 having 104 teeth, combined with the module of 1.5 and the pressure angle of 17.5°, results in optimized meshing efficiency and minimized transmission losses. Overall, the transmission unit 100 delivers improved performance efficiency, compactness, and durability, making the transmission unit 100 highly suitable for modern electric vehicles that demand both performance and space optimization.
In an embodiment, the multi-speed transmission unit 100 for the electric vehicle. The transmission unit 100 comprising the GPD 102 mounted on the motor shaft and the GPDn 104 mounted on the clutch shaft. The GPD 102 and the GPDn 104 are configured to achieve the contact ratio of two or more. Further, the GPD 102 comprises the inner square spline coupling 106 configured to engage with the motor shaft for facilitating torque transfer. Furthermore, the GPDn 104 comprises the central hub portion 108 configured to couple with the clutch shaft. Moreover, the GPDn 104 is operatively coupled to the clutch mechanism, the power is transferred to the main shaft through the clutch mechanism, and the clutch mechanism isolates the input shaft from the motor. Moreover, the GPD 102 comprises 51 teeth and the GPDn 104 comprises 104 teeth. Moreover, the GPD 102 and GPDn 104 are configured with the module of 1.5 and the pressure angle of 17.5°. Moreover, the GPD 102 and GPDn 104 is configured together to provide the gear ratio of 2.039. Additionally, the GPD 102 and GPDn 104 are made of hardened alloy steel.
In the description of the present disclosure, 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 disclosure 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.
,CLAIMS:1. A multi-speed transmission unit (100) for an electric vehicle, the transmission unit (100) comprising:
- a gear primary drive (GPD) (102) mounted on a motor shaft; and
- a gear primary driven (GPDn) (104) mounted on a clutch shaft,
wherein the GPD (102) and the GPDn (104) are configured to achieve a contact ratio of two or more.
2. The transmission unit (100) as claimed in claim 1, wherein the GPD (102) comprises an inner square spline coupling (106) configured to engage with the motor shaft for facilitating torque transfer.
3. The transmission unit (100) as claimed in claim 1, wherein the GPDn (104) comprises a central hub portion (108) configured to couple with the clutch shaft.
4. The transmission unit (100) as claimed in claim 1, wherein the GPDn (104) is operatively coupled to a clutch mechanism, wherein power is transferred to the main shaft through the clutch mechanism, and the clutch mechanism isolates the input shaft from the motor.
5. The transmission unit (100) as claimed in claim 1, wherein the GPD (102) comprises 51 teeth and the GPDn (104) comprises 104 teeth.
6. The transmission unit (100) as claimed in claim 1, wherein the GPD (102) and GPDn (104) are configured with a module of 1.5 and a pressure angle of 17.5°.
7. The transmission unit (100) as claimed in claim 1, wherein the GPD (102) and GPDn (104) configured together to provide a gear ratio of 2.039.
8. The transmission unit (100) as claimed in claim 1, wherein the GPD (102) and GPDn (104) are made of hardened alloy steel.
Dated: 11/10/2025