DESC:CONTINUOUS VARIABLE TRANSMISSION FOR ELECTRIC VEHICLE
CROSS REFERENCE TO RELATED APPLICTIONS
The present application claims priority from Indian Provisional Patent Application No. 202321012854 filed on 25-02-2023, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
Generally, the present disclosure relates to transmission systems. Particularly, the present disclosure relates to a belt-type continuous variable transmission (CVT) drive.
BACKGROUND
In the domain of mechanical engineering, significant emphasis has been placed on the development and optimization of transmission systems. Transmission systems are utilized for transferring power from a motor or engine to the wheels or other machinery, enabling controlled application of power. Among various types of transmission systems, the continuous variable transmission (CVT) has gained prominence due to its ability to provide seamless acceleration without the need for gear shifting, thereby ensuring a smooth and efficient power delivery.
One commonly utilized approach in CVT technology involves the use of a belt and pulley system, which adjusts the transmission ratio by changing the diameter of the pulleys around which the belt is looped, thus allowing an infinite number of gear ratios between maximum and minimum values. The adaptability of such systems to varying load conditions and their contribution to enhancing fuel efficiency and driving experience is well known.
However, the performance of traditional belt driven CVTs is often challenged under extreme load conditions and high torque applications. The rigidity of the pulleys can limit the range of transmission ratios achievable and affect the transmission's efficiency. Furthermore, the fixed nature of pulley diameters in conventional designs does not always allow for optimal power transmission in varied operating conditions.
Further, another approach within CVT technology involves the use of torque converter systems, which utilize a fluid coupling mechanism to transfer rotating power from the engine/motor to tyre. While offering smooth power transfer without the need for physical contact between moving parts, such systems often suffer from efficiency losses due to slippage and the inherent nature of fluid dynamics involved.
Moreover, the application of electronic control systems in CVTs has been explored to enhance the performance and adaptability of these transmissions. These systems control the CVT's operation through different mechanisms and sensors, aiming to optimize the power delivery and efficiency dynamically. Despite the improvements offered by electronic controls, issues such as system complexity, cost, and reliability remain concerns that impact their widespread adoption.
Collating the issues associated with traditional belt driven CVTs, torque converter systems, and electronically controlled CVTs, it is evident that each method has drawbacks, ranging from limited efficiency and adaptability to high costs and complexity. Other transmission systems are also known but are often associated with their unique sets of challenges, including mechanical complexity, maintenance requirements, and operational limitations.
In light of the above discussion, there exists an urgent need for solutions that overcome the problems associated with conventional transmission systems to optimize power delivery, enhance efficiency, and improve adaptability across varying operational conditions.
SUMMARY
An object of the present disclosure is to provide a a belt-type continuous variable transmission (CVT) drive for an electric vehicle with improved efficiency and compact size.
In an aspect, the present disclosure provides a belt-type continuous variable transmission (CVT) system comprising an input drum to receive rotational motion, an output drum, and a flexible belt looped around both the input drum and the output drum. The flexible belt transfers rotational motion from the input drum to the output drum. Either or both drums are deformable to change their diameters, thereby adjusting the transmission ratio. The inclusion of deformable drums facilitates a dynamic adjustment of gear ratios, enhancing the efficiency of power transmission and adaptability to varying load conditions.
The present disclosure a belt-type continuous variable transmission (CVT) system for electric vehicles with increased efficiency and performance. Advantageously, the disclosed CVT system allows continuous, stepless adjustment of gear ratios, enabling the vehicle or machine to operate at the optimal power band across a wide range of speeds. Further, the disclosed CVT system maintains the motor within most efficient operating range for a broader spectrum of driving to improve fuel/energy efficiency. Furthermore, the CVT drive is advantageous in terms of compact design and reduced weight, contributing to the overall efficiency and performance of electric vehicles. Additionally, absence of manual gear shifting the vehicle does not experience the jerky transitions typical of conventional transmissions, the CVT system of present disclosure enables smooth operation to improve user (i.e., driver or passenger) comfort and also reduces wear on the drivetrain components.
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:
FIG. 1 illustrates a belt-type continuous variable transmission (CVT) system, in accordance with embodiment of present disclosure.
FIG. 2 illustrates a cross sectional view of CVT system (of Figure 1), in accordance with embodiment of present disclosure.
FIG. 3 illustrates the input drum is depicted in a deformed state (e.g., transformation from initial configuration as seen in Figure 2), in accordance with embodiment of 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 belt-type continuous variable transmission 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 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, 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, 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” is used to 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 "toroidal continuous variable transmission" or "CVT system" or “CVT drive” refers to a specific type of transmission system that allows for a seamless change in the gear ratio between the engine and wheels in real-time, without perceptible steps or shifts. This system employs a toroidal (doughnut- or cone-shaped) design to facilitate the variable transmission of power and torque from the engine to the wheels. Unlike traditional transmissions with fixed gear ratios, the toroidal CVT drive adjusts the gear ratio continuously based on driving conditions, enhancing vehicle performance, fuel efficiency, and the driving experience.
As used herein, the term "first drum" or “input drum” refers to a conical component of the continuous variable transmission (CVT) drive, which is mounted on an input shaft. The primary function of the input drum is to receive rotational input from the power source of the vehicle, such as an electric motor. The input drum plays a crucial role in the initial stage of power transmission, acting as the interface between the power source and the CVT drive mechanism. Further, through the engagement of the input drum with other components, such as rollers, the input drum enables the transmission of power to the output cone, contributing to the variable adjustment of gear ratios.
As used herein, the term "input shaft" denotes a shaft on which the input drum is mounted within the CVT drive. This shaft is a critical component for transferring rotational input from the power source to the input drum. The input shaft serves as the primary conduit for mechanical power, connecting the source of the power directly to the transmission system. The design and construction of the input shaft are essential for ensuring the efficient and reliable transmission of power within the CVT drive, contributing to the overall performance of the electric vehicle.
As used herein, the term "second drum" or “output drum” refers to a conical component within the CVT drive, which is mounted on an output shaft. The primary role of the output drum is to receive the rotational input transmitted by the roller from the input drum and to transfer this input to the drivetrain of the vehicle. The output drum is integral to the CVT mechanism, allowing for the continuous variability in gear ratios by altering its engagement with the roller. This component is crucial for adapting the power output to match driving conditions, thereby enhancing vehicle efficiency and performance.
As used herein, the term "output shaft" denotes a shaft on which the output drum is mounted within the CVT drive. This shaft plays a pivotal role in conveying the adjusted rotational input from the output drum to the drivetrain. The output shaft is fundamental to the operation of the CVT drive, facilitating the final stage of power transmission and ensuring that the variable gear ratios generated by the CVT drive are effectively applied to the wheels of the vehicle. The design of the output shaft is critical for maintaining the integrity and responsiveness of the transmission system.
As used herein, the term "driving belt" denotes a flexible, durable band looped around both the first and output drums within the CVT drive, responsible for the transmission of rotational motion from the input drum to the output drum. This belt allows transfer of power with variable gear ratios through ability to adjust in effective length. The adaptability of the driving belt to changes in the radius of either drum underpins the CVT's capacity to offer seamless, continuous changes in gear ratios, optimizing vehicle performance across a wide range of operating conditions.
As used herein, the term "deformation" of the input drum or output drum refers to the alteration in the shape, specifically the diameter, of the respected drum of belt type CVT drive. The deformation can be achieved through the radial displacement of components (e.g., curved segments) surrounding the central hub. The process of deformation allows for the dynamic adjustment of the effective diameter of drum, to alter gear ratio of belt type CVT drive. Deformation can modulate gear ratio, which controls the speed or torque output of the vehicle's drivetrain. When the diameter of the drum is increased through deformation can increase the gear ratio, typically resulting in higher speed and torque reduction. Conversely, decreasing the diameter of the drum can cause reduction of the gear ratio and increasing torque. Thus, dynamic adjustment mechanism enables the belt type CVT drive can be provided with variable range of gear ratios without the need for traditional gear changes, allowing for optimized vehicle performance across various driving conditions. The capability to deform the drums and thereby adjust their diameters can enable control of speed and torque, for efficient power delivery and enhancing the driving experience.
Figure 1, in accordance with an embodiment describes a belt-type continuous variable transmission (CVT) drive (100), in accordance with embodiment of present disclosure. The belt-type continuous variable transmission (CVT) system (100) as used throughout the present disclosure relates to a mechanical assembly to provide seamless transition through an infinite number of effective gear ratios, to enable efficient transmission of power and torque from an engine/motor or other power source to the wheels of a vehicle or any machinery requiring variable speed control. The system 100 comprises an input drum (102) to receive rotational motion. Rotational motion is imparted to the input drum (102) from an engine/motor or other power-generating device. The input drum (102), at the initial stage of power transmission, transfers rotational energy to the rest of the CVT mechanism. In an embodiment, the input drum (102) may comprise a surface treatment or design modification to enhance grip or reduce wear on the flexible belt (106) looped around input drum (102).
The belt-type CVT system (100) further comprises an output drum (104) that receives the rotational motion transferred from the input drum (102) via the flexible belt (106). The output drum (104) converts the received rotational motion into output torque, which is then transmitted to the drivetrain or machinery connected to the CVT system (100). The output drum (104) enables the CVT system (100) to adjust the output speed and torque according to the requirements of the connected wheels or machinery. In an embodiment, the output drum (104) may optimize the transfer of motion and to accommodate various operational conditions.
In an embodiment, a flexible belt (106) is simultaneously looped around both the input drum (102) and the output drum (104). The flexible belt (106) transfers rotational motion from the input drum (102) to the output drum (104), thereby facilitates the continuous variation of gear ratios without the need for physical gear changes. The flexible belt (106) efficiently transmits power under varying tensions and pulley diameters for the operation of the CVT system (100). In an embodiment, the flexible belt (106) may be constructed from materials offering high durability and reduced slippage to ensure reliable performance over service life.
Furthermore, the CVT system (100) may incorporate the input drum (102) and/or the output drum (104), both being deformable to respectively change diameter thereof. Said deformation capability enables the CVT system (100) to alter the effective diameters of the input drum (102) and output drum (104), thereby adjusting the gear ratio dynamically according to the load requirements and operational conditions. The deformable nature input drum (102) and output drum (104) enable optimizing performance and efficiency of the CVT system (100), allowing a smoother acceleration curve and better fuel/energy efficiency in automotive applications. In an embodiment, the mechanism for varying the drum diameters may include hydraulic, mechanical, or electronic control systems to achieve the desired level of responsiveness in diameter adjustment.
Figure 1, in accordance with an embodiment describes a cross sectional view of CVT system (of Figure 1), in accordance with embodiment of present disclosure. The input drum (102) comprises a first central hub (202A) and a first set of multiple curved members (204B), connected pivotically to said first central hub (108). The first central hub (202A) serves as the core around which the curved members (204B) are arranged, facilitating the transmission of rotational motion to the flexible belt (106). The connection of the curved members (204B) to the first central hub (202A) enables adjustments in the configuration of the input drum (102) to alter the transmission/gear ratio efficiently. In an embodiment, the design of the first central hub (202A) and the curved members (204B) may incorporate materials or geometries that optimize their durability and performance under varying operational conditions.
In another embodiment, the output drum (104) includes a second central hub (204A) and a second set of multiple curved members (204B), which pivotically connected to said second central hub (204A). Similar to the input drum (102), the second central hub (204A) can be utilized for the attachment of the curved members (204B), for transferring the rotational motion received from the flexible belt (106). The pivotical connection facilitates dynamic adjustment of effective diameter of the output drum (104), thereby enabling the CVT system (100) to vary output characteristics of output drum (104) in response to changing demands. In an embodiment, optimizations in the design or material selection for the second central hub (204A) and curved members (204B) may be implemented to enhance overall efficiency.
Further, each curved member (204B) of the first set of multiple curved members (204B) is connected to the first central hub (202A) using a first bearing to enable movement with respect to the first central hub (108). The first bearing ensures smooth adjustments of the curved members (204B), required for the modulation of the input drum (102) diameter without compromising the stability of the transmission system. In an embodiment, the first bearings may provide high performance even under high stress or variable load conditions, therefore more reliability of the CVT system (100). The first bearing permits the precise and smooth movement of the curved members (202B), for the rapid and responsive adjustment of diameter of input drum (102).
According to the arrangement, each curved member (114) of the second set of multiple curved members (204B) is connected to the second central hub (204A) using a second bearing to facilitate movement of each curved member (114) with respect to the second central hub (204A). Said setup mirrors the functionality observed in the input drum (102), allowing for analogous adjustments in the output drum (104) that cater to the seamless variation of gear ratios. In an embodiment, the second bearings may accommodate the specific operational parameters associated with the output drum (104), enhancing adaptability and performance of the CVT system (100). The second bearing allows smooth and controlled movement of for each curved member (204B) relative to the second central hub (202A) to allow accurate and efficient alteration of diameter the output drum (104), facilitating adaptation to changes in driving dynamics.
In yet another embodiment, the extension or retraction of the first curved members (202B) associated with the first central hub (202A) enables the input drum (102) to vary diameter thereof to alter the gear ratio between the input drum (102) and output drum (104), thus providing a mechanism for adjusting performance of the CVT system (100) based on the operational requirements. In an embodiment, mechanisms for extending and retracting the first curved members (202B) can enable enhancement of precision, durability, and responsiveness.
In an embodiment, the deformability of the input drum (102) adjusts diameter thereto, to directly manage the gear ratio of the transmission to enable efficient power transfer under varying load conditions, optimizing the performance of motor/engine based on speed and torque requirements of the vehicle. Furthermore, capacity of the input drum (102) to change diameter enhances smoother transition between gear ratios, leading to an improvement in fuel/energy efficiency and driving experience.
Figure 3, in accordance with an embodiment the input drum (102) is depicted in a deformed state (e.g., transformation from initial configuration as seen in Figure 2), in accordance with embodiment of present disclosure. The deformation can be achieved through a symmetrical radial displacement of each first curved segment (202B) with respect to the first central hub (202A). The displacement of each curved segment (202B) can cause alteration the overall radius of the input drum (102), effectively modifying the contact surface for the driving belt (106) that loops around both the input drum (102) and output drum (104). As the curved segments (202B) move radially outward from the first central hub (202A), the effective diameter of the input drum (102) increases. This enlargement/deformation of the input drum (102) can cause increment of diameter to a change in the gear ratio. For an instance, the input drum (102) of Figure 2 has a radius of 40 mm, wherein the driving belt (106) loop around the output drum (104) has a radius of 40 mm. The initial equal diameter can be resulted in gear ratio suited for lower speed but higher torque. The radial displacement of the curved segments (202B) increases the radius of input drum (102) to 50 mm. As a result of deformation of the input drum (102), the gear ratio is altered to shift towards a higher gear ratio. This means that for each rotation of the input drum (102), the output drum (104) would turn fewer times than before, translating higher speed with increased torque.
In a first exemplary scenario, diameter deformity of the input drum (102) can be achieved in various ways. For an instance, upon receiving a control signal, first set of multiple curved members (202B) are actuated to pivot inwards or outwards relative to the first central hub (202A). The pivotal movement, first set of multiple curved members (202B) results in the deformation of diameter of the input drum (102). Such deformation allows adjustment of the transmission ratio by altering the contact surface area between the flexible belt (106) and the input drum (102). The deformation mechanism of input drum (102) enables precise control over the transmission characteristics, enabling the adaptation of the CVT system (100) to varying operational demands of EV. The deformation of input drum (102) provides an efficient means to modify the transmission ratio without the need for complex electronic controls.
In a second exemplary scenario, similar to the input drum, the output drum comprises second central hub (204A) and second set of multiple curved members (204B) pivotally connected thereto. The deformation of the output drum (104) can be facilitated through the actuation of second set of multiple curved members (204B). Such actuation causes the second set of multiple members (204B) to pivot, thereby altering the diameter of the output drum (104) to alter the transmission/gear ratio by changing the effective diameter over which the flexible belt (106) operates. The deformity the output drum (104) on demand enables the CVT system (100) to regulate output characteristics dynamically, catering to varying load conditions and optimizing performance.
In another embodiment, the curved members (204B) are extendable or retractable with respect to the second central hub (204A) to adjust the diameter associated with the output drum (104). The aforementioned feature complements the functionality provided by the input drum (102), enabling ratio variation within the CVT system (100). In an embodiment, the extension and retraction mechanism for the output drum (104) may include control systems to optimize the transition between different gear ratios.
The first central hub (202A) can provide a stable axis for the connection of multiple first curved members (202B), which being pivotally connected to the first central hub (202A) to dynamic alteration diameter of input drum (102), to control the gear ratio. The deformation facilitates the adjustment of the transmission ratio for optimal power delivery across varying operational demands.
Imagine a driver accelerating electric vehicle equipped with a CVT system (100) of present disclosure. As the driver presses the accelerator, the onboard Vehicle Control Unit (VCU) signals the CVT system (100) to optimize for torque enable quick and responsive start. The VCU commands the input drum (102), which receives rotational motion from the electric motor, to decrease radius. Simultaneously, VCU may trigger signal to increase radius of the output drum (104). The alteration in radius (i.e., deformation) of input drum (102) and output drum (104) can increase the gear ratio and maximizing torque. Further, as the vehicle reaches higher speeds, VCU directs a reversal of the initial deformation process (i.e., increases the radius of the input drum (102) and decreases the radius of the output drum (104)) to reduce gear ratio to achieve higher speeds with lower engine RPM, enhancing energy efficiency and reducing wear. The VCU continuously monitors vehicle speed, acceleration demands, and other driving conditions to manage deformation of the input drum (102) and/or output drum (104) in real-time to ensure the optimal gear ratio can be achieved by expanding or contracting the input drum (102) and/or output drum (104).
In an exemplary embodiment, upon receiving a command from the VCU, a first motor associated with the input drum (102) initiates rotation in either clockwise or anticlockwise. The direction and extent of the rotation determine the movement of the curved segments (202B). As the first motor rotates, the curved segments (202B) can pivot around connections to the first central hub (202A) to alter diameter of input drum (102). Clockwise rotation might contract the input drum (102) for a higher gear ratio, while anticlockwise rotation could expand input drum (102) for lower gear ratio. Similar to the input drum (102), the output drum (104) mirrors the functionality of the output drum (102) (i.e., second set of multiple curved segments (204B) pivotally connected to second central hub (204A)), enabling output drum (104) to independently adjust diameter through deformation. The output drum (104) can be associated with a second motor, which is controlled by the VCU. Based on the demanded speed, torque requirements, or other parameters, the VCU control the second motor to rotate in a specific manner. The rotation of second motor affects the pivotal connections of the second curved segments (204B) to the second central hub (204A), altering the diameter of the output drum (104). The clockwise or anticlockwise of rotation of second motor and magnitude thereof can influence how much the output drum (104) deforms—either increasing or decreasing diameter of output drum (104) to adjust the gear ratio of CVT system (100). The VCU monitors various parameters, such as vehicle speed, acceleration, load, and driver inputs to calculate the optimal gear ratio needed at any given moment. To achieve the calculated gear ratio, the VCU triggers commands precise commands to the first motor associated with the input drum (102) and second motor of output drum (104). The triggered commands include the direction and amount of rotation necessary to adjust the diameter of input drum (102) and the output drum (104) to enable efficient vehicle operation by achieving smooth acceleration and deceleration and optimizing energy consumption.
In the embodiments, a frictional material can be disposed on the external surfaces of each set of curved members (110, 114), enhancing the grip between the drums (102 and 104) and the flexible belt (106). Moreover, such disposal prevents slippage and also enables efficient power transfer throughout the varied operational conditions. In an embodiment, the frictional material may be selected based on its wear resistance and compatibility with the belt material to maximize the lifespan and efficiency of the CVT system (100)
In an embodiment, the multiple grooves can be disposed on the external surfaces of the curved members (110, 114) to enable efficient engagement with flexible belt (106). The grooves can align with structure of flexible belt (106) to enable secure and efficient transfer of motion while minimizing wear and enhancing reliability of CVT system (100). In an embodiment, the geometry of the grooves may be optimized to accommodate various belt designs, further improving the adaptability of the CVT system (100).
In yet another embodiment, the flexible belt (106) can be lengthened or shorten to accommodate changes in the diameters associated with the input drum (102) and output drum (104) for maintaining tension and operational efficiency, as the CVT system (100) adjusts to different gear ratios. In an embodiment, the flexible belt (106) may incorporate elastic or adjustable segments to facilitate said functionality.
In the embodiments, the flexible belt (106) comprises multiple interconnected links with a pivoting mechanism to enable length adjustment of flexible belt (106). The interconnected links design of flexible belt (106) allows control over the length of flexible belt (106) to enable optimal engagement with the drums (102 and 104) across different operational conditions. As the diameters of the drums (102 and 104) vary, effective length of flexible belt (106) also adapts to maintain optimal tension and alignment. The links within the flexible belt (106) are configured to pivot in relation to each other, allowing the flexible belt (106) to extend or contract. The pivotal action can be finely tuned in response to the changes in diameter of the input drum (102) and/or output drum (104) to accommodate different circumferences without compromising on tension or efficiency. When either input drum (102) or output drum (104) undergoes deformation—expanding or contracting— the pivoting mechanism within the flexible belt (106) links can be activated, either closing gaps to shorten the belt for a smaller drum diameter or widening gaps to lengthen the belt for a larger drum diameter to enable adaption to the changing geometry of the drums (102, 104), maintaining a constant and efficient transfer of power within the CVT system (100).
The output drum (104) receives the rotational motion transferred through the flexible belt. Similar to the input drum (102), the ability change in diameter of output drum (104) adjusts the gear ratio for allowing the CVT system to adapt to different driving conditions. Said adaptability ensures a continuous range of gear ratios, eliminating the steps or shifts found in traditional transmissions. The output drum's deformation capability contributes to the system's versatility, enabling maintaining of optimal engine/motor speeds and improve vehicle acceleration and efficiency.
In an embodiment, the flexible belt (106) can be looped around both the input drum (102) and output drum (104), facilitating the transfer of rotational motion from the former to the latter. The flexibility and durability of flexible belt (106) maintain consistent contact with both drums (102 and 104), as either or both drums (102 and 104) deform to alter diameters. The flexibility enables reliable and efficient transfer of power across the CVT system (100). Moreover, the flexible belt (106) also minimizes slippage and wear, contributing to the overall longevity and reduced maintenance needs of the transmission CVT system (100).
The alteration of diameter of both input drum (102) and output drum (104), length of flexible belt (106), enable CVT system (100) to offer a seamless and efficient transmission of power. The adjust the diameters and length of drums (102 and 104) and flexible belt (106) allows for a wide range of gear ratios to be achieved without the need for physical gear changes. Thereby, leads to a smoother driving experience, as it can automatically adjust to the optimal gear ratio for any given driving condition. Thus, the CVT system (100) of present disclosure facilitates improved fuel/energy efficiency, enhanced vehicle acceleration, and a reduction in engine/motor wear, making the CVT system (100) effective solution for automotive transmission requirements.
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 belt-type continuous variable transmission (CVT) system (100), the belt-type CVT system (100) comprising:
- an input drum (102) to receive rotational motion;
- an output drum (104); and
- a flexible belt (106) simultaneously looped around both the input drum (102) and the output drum (104), wherein the flexible belt (106) transfers rotational motion from the input drum (102) to the output drum (104) and wherein the input drum (102) and/or the output drum (104) is deformable to respectively change a diameter associated with the input drum (102) and/or a diameter associated with the output drum (104).
2. The belt-type CVT system (100) as claimed in claim 1, wherein the input drum (102) comprises:
- a first central hub (202A); and
- a first set of multiple curved members (202B) pivotally connected to the first central hub (202A).
3. The belt-type CVT system (100) as claimed in claim 2, wherein each curved member (202B) of the first set of multiple curved members (202B) is connected to the first central hub (202A) using a first bearing to enable pivotal movement of each curved member (202B) of the first set of multiple curved members (202B) with respect to the first central hub (202A).
4. The belt-type CVT system (100) as claimed in claim 2, wherein each curved member (202B) of the first set of curved members (202B) comprises a frictional material (120) disposed on an external surface thereof.
5. The belt-type CVT system (100) as claimed in claim 2, wherein the output drum (104) comprises:
- a second central hub (204B); and
- a second set of multiple curved members (204B) pivotally connected to the second central hub (204B).
6. The belt-type CVT system (100) as claimed in claim 5, wherein:
- each curved member (204B) of the second set of multiple curved members (204B) is extended radially with respect to the second central hub (204B) to increase the diameter associated with the output drum (104); and
- each curved member (204B) of the second set of multiple curved members (204B) is retracted radially with respect to the second central hub (204B) to decrease the diameter associated with the output drum (104), wherein the extension or retraction of the second set of curved members (204B) changes the gear ratio between the input drum (102) and the output drum (104).
7. The belt-type CVT system (100) as claimed in claim 5, wherein each curved member (204B) of the second set of multiple curved members (204B) is connected to the second central hub (204B) using a second bearing to enable pivotal movement of each curved member (204B) of the second set of multiple curved members (204B) with respect to the second central hub (204B).
8. The belt-type CVT system (100) as claimed in claim 5, wherein each curved member (204B) of the second set of curved members (204B) comprises a frictional material (122) disposed on an external surface thereof.
9. The belt-type CVT system (100) as claimed in claim 8, wherein the external surface of each curved member (202B) of the first set of curved members (202B) comprises multiple grooves to receive the flexible belt (106).
10. The belt-type CVT system (100) as claimed in claim 9, wherein the external surface of each curved member (204B) of the second set of curved members (204B) comprises multiple grooves to receive the flexible belt (106).
11. The belt-type CVT system (100) as claimed in claim 1, wherein the flexible belt (106) is:
- lengthened to accommodate for the change in the diameter associated with the input drum (102) and/or the output drum (104); and
- shortened to accommodate for the change in the diameter associated with the input drum (102) and/or the output drum (104).
12. The belt-type CVT system (100) as claimed in claim 12, wherein the flexible belt (106) comprises multiple interconnected links that allow for lengthening or shortening of a length of the flexible belt (106).
13. The belt-type CVT system (100) as claimed in claim 13, wherein each interconnected link comprises a pivoting mechanism to enable the lengthening or shortening of the length of the flexible belt (106).