Patent Description:
In the last few decades, significant growth and development is witnessed in the realm of electric vehicles. Factors, such as space constraint, gradeability, and weight have proven to be the primary concerns in the current stage of development of the electric vehicles.

Generally, electric vehicles, such as four-wheelers buses and trucks are equipped with a single speed fixed transmission with an objective of minimizing drive train mass, volume, losses, and associated cost. Further, such electric vehicles also include a Brushless Direct Current (BDLC) motor for providing operational power to the transmission. The torque and speed characteristic of the existing type of BDLC motor is such that the vehicles achieve good low speed torque, but at the expense of top vehicle speeds. Therefore, while these vehicles can achieve gradeability, i.e., low-speed torque, they cannot achieve higher speeds.

Now, in case of Rickshaw and cargo electric vehicles, even consumers expect higher payload capacity and gradeability performance from the vehicle instead of increased energy efficiency, so that the vehicle can accommodate a greater number of passengers. This is also because the running cost of the electric vehicles is much lower than the running cost of an Internal Combustion Engine-powered vehicles. However, with the advent of electric vehicle technologies, increase in fuel efficiency is now desired even in the electric vehicles as far as it does not hamper the payload capacity of the vehicle.

Now, to achieve both the gradeability and the higher top speed for these vehicles, bigger capacity motors are required. However, incorporating bigger capacity motors and associated components would lead to certain issues, such as space constraints in the electric vehicle and an undesirable increase in an overall weight of the vehicle.

A two-speed transmission system according to the preamble part of claim <NUM> is known from <CIT>.

This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.

In an embodiment of the present invention, a two-speed transmission system for an electric vehicle is disclosed. The two-speed transmission system includes a housing, a one-way clutch assembly adapted to be mounted on an input shaft and to be coupled with a first gear drive, and a multi-plate friction clutch assembly adapted to be mounted on the input shaft. The multi-plate friction clutch assembly includes a clutch hub disposed in the housing and mounted on the input shaft. The system includes a second gear drive freely mounted on the input shaft and having external spline on an outer diameter adapted to be engaged with the clutch hub of the multi-plate friction clutch assembly. The one-way clutch assembly is adapted to rotate to operate the vehicle in the first gear drive when the input shaft is rotated in a drive direction, and the multi-plate friction clutch assembly is in a disengaged state when the vehicle is operated in the first gear drive.

In another embodiment of the present invention, an electric vehicle is disclosed. The electric vehicle includes an electric motor, an input shaft coupled with the electric motor, and a two-speed transmission system coupled to the input shaft. The two-speed transmission system includes a housing, a one-way clutch assembly adapted to be mounted on an input shaft and to be coupled with a first gear drive, and a multi-plate friction clutch assembly adapted to be mounted on the input shaft. The multi-plate friction clutch assembly includes a clutch hub disposed in the housing and mounted on the input shaft. The system includes a second gear drive freely mounted on the input shaft and having external spline on an outer diameter adapted to be engaged with the clutch hub. The one-way clutch assembly is adapted to rotate to operate the vehicle in the first gear drive when the input shaft is rotated in a drive direction, and the multi-plate friction clutch assembly is in a disengaged state when the vehicle is operated in the first gear drive.

To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. The invention will be described and explained with additional specificity and detail with the accompanying drawings.

Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have been necessarily been drawn to scale. For example, the flow charts illustrate the method in terms of the most prominent steps involved to help to improve understanding of aspects of the present invention. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

For promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

For the sake of clarity, the first digit of a reference numeral of each component of the present invention is indicative of the Figure number, in which the corresponding component is shown. For example, reference numerals starting with digit "<NUM>" are shown at least in <FIG>. Similarly, reference numerals starting with digit "<NUM>" are shown at least in <FIG>.

<FIG> illustrates a schematic perspective view of a transmission architecture <NUM> of an electric vehicle, according to an embodiment of the present invention. In an embodiment, the transmission architecture <NUM> ma be employed in a three-wheeler or a four-wheeler vehicle. For the ease of readability, the electrical vehicle is hereinafter interchangeably referred to as the vehicle. The transmission architecture <NUM> is shown to include an electric motor <NUM> to provide drive, a two-speed transmission system <NUM> coupled with the electric motor <NUM>, a clutch actuation motor <NUM> adapted to actuate clutch operation, a clutch position sensor <NUM> adapted to detect a position of the clutch, a reverse gear actuation system <NUM> adapted to actuate a reverse gear drive, and a differential output shaft <NUM>. For the ease of readability, the two-speed transmission system <NUM> is hereinafter interchangeably referred to as the transmission system <NUM>.

<FIG> illustrates a front cross-sectional view <NUM> and a side cross-sectional view <NUM> of the transmission architecture <NUM>, according to an embodiment of the present invention. The electric vehicle may include an adapter flange <NUM> adapted to couple the electric motor <NUM> with a housing <NUM> of the transmission system <NUM>. In an embodiment, the adapter flange <NUM> may be mounted by using bolts. Due to the adapter flange <NUM>, the transmission system <NUM> may be conveniently coupled with different motors. <FIG> illustrates a magnified front cross-sectional view of the transmission architecture <NUM> depicting various components, according to an embodiment of the present invention. Referring to <FIG>, <FIG>, and <FIG>, the transmission system <NUM> may include, but is not limited to, the housing <NUM>, a one-way clutch assembly <NUM> adapted to be mounted on an input shaft <NUM> and to be coupled with a first gear drive assembly <NUM>, and a multi-plate friction clutch assembly <NUM> adapted to be mounted on the input shaft <NUM>. In an embodiment, the input shaft <NUM> may be coupled with the electric motor <NUM> through a key or a spline interface.

In an embodiment, a housing of the one-way clutch assembly <NUM> may be coupled with a housing <NUM> of the multi-plate friction clutch assembly <NUM>. Particularly, the housing <NUM> of the multi-plate friction clutch assembly <NUM> may include a riveted one-way clutch flange positioned on the input shaft <NUM>. Further, the one-way clutch flange may be adapted to be press-fitted into the housing of the one-way clutch assembly <NUM>.

In another embodiment, the housing of the one-way clutch assembly <NUM> may be an integral part of the housing <NUM> of the multi-plate friction clutch assembly <NUM>. In such an embodiment, both the housings may be formed of the same material and the one-way clutch assembly <NUM> may be press-fitted on to the housing <NUM> of the multi-plate friction clutch assembly <NUM>. In the present embodiment, the need of the one-way clutch flange and the riveting is eliminated.

The multi-plate friction clutch assembly <NUM> may include, but is not limited to, a clutch hub <NUM> disposed in the housing <NUM> and mounted on the input shaft <NUM>. In an embodiment, the multi-plate friction clutch assembly <NUM> may include at least one roller bearing <NUM> adapted to be disposed between the input shaft <NUM> and the clutch hub <NUM> to minimize friction. The at least one roller bearing <NUM> may be an axial thrust bearing. Further, the multi-plate friction clutch assembly <NUM> may also include a friction plate having outer lugs adapted to slide in the housing, a pressure plate having lugs on an internal diameter adapted to slide an outer diameter of the clutch hub <NUM>, and a number of compression springs adapted to exert clamping pressure to keep the friction plate and the pressure plate together.

Further, the transmission system <NUM> may also include a second gear drive assembly <NUM> freely mounted on the input shaft <NUM>. The second gear drive assembly <NUM> may include, but is not limited to, external spline on an outer diameter adapted to be engaged with the clutch hub <NUM> of the multi-plate friction clutch assembly <NUM>.

In an embodiment, the one-way clutch assembly <NUM> may be adapted to rotate to operate the vehicle in the first gear drive when the input shaft <NUM> is rotated in a drive direction. Further, the multi-plate friction clutch assembly <NUM> may be in a disengaged (open) state when the vehicle is operated in the first gear drive. In such an embodiment, the second gear drive assembly <NUM> may be adapted to freely rotate along with the clutch hub <NUM> of the multi-plate friction clutch assembly <NUM> on the input shaft <NUM>.

In another embodiment, when the vehicle is operated in a second gear drive, the multi-plate friction clutch assembly <NUM> may be adapted to be in an engaged state. In such an embodiment, owing to the engaged state of the multi-plate friction clutch assembly <NUM>, the drive from the motor <NUM> is transmitted through the second gear drive assembly <NUM> to operate the vehicle in the second gear drive.

In an embodiment, the first gear drive assembly <NUM> and the second gear drive assembly <NUM> may be coupled with a first gear driven assembly <NUM> and a second gear driven assembly <NUM>, respectively. The first gear driven assembly <NUM> and the second gear driven assembly <NUM> may then be coupled with a counter shaft <NUM>. The counter shaft <NUM> may be coupled to a differential gear assembly <NUM> mounted on the differential output shaft <NUM>.

In an embodiment, the transmission system <NUM> may include a speed sensor adapted to detect a speed of the vehicle and a throttle sensor adapted to detect driving load of the vehicle. In an embodiment, the sensors may not be separate new components to be employed in the vehicle. In fact, the sensors may be understood as an existing sensor of the vehicle, for example, of an Electronics Control Unit of the vehicle. For example, the sensors <NUM> may be associated with a tachometer or a speedometer of the vehicle.

Further, the speed sensor and the throttle sensor may be in communication with a controller of the transmission system <NUM>. In an embodiment, the controller may include, but is not limited to, a processor, a memory, modules, and data. The modules and the memory may be coupled to the processor. The processor can be a single processing unit or several units, all of which could include multiple computing units. The processor may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. Among other capabilities, the processor may be configured to fetch and execute computer-readable instructions and data stored in the memory.

The memory may include any non-transitory computer-readable medium known in the art including, for example, volatile memory, such as static random access memory (SRAM) and dynamic random access memory (DRAM), and/or non-volatile memory, such as read-only memory (ROM), erasable programmable ROM, flash memories, hard disks, optical disks, and magnetic tapes.

The modules, amongst other things, include routines, programs, objects, components, data structures, etc., which perform tasks or implement data types. The modules may also be implemented as, signal processor(s), state machine(s), logic circuitries, and/or any other device or component that manipulate signals based on operational instructions.

Further, the modules can be implemented in hardware, instructions executed by a processing unit, or by a combination thereof. The processing unit can comprise a computer, a processor, such as the processor, a state machine, a logic array, or any other suitable devices capable of processing instructions. The processing unit can be a general-purpose processor which executes instructions to cause the general-purpose processor to perform the required tasks or, the processing unit can be dedicated to perform the required functions. In another embodiment of the present invention, the modules may be machine-readable instructions (software) which, when executed by a processor/processing unit, perform any of the described functionalities. Further, the data serves, amongst other things, as a repository for storing data processed, received, and generated by one or more of the modules.

The controller may be adapted to control an operational state of the multi-plate friction clutch assembly <NUM> based on the speed of the vehicle and the driving load of the vehicle. The operational state of the multi-plate friction clutch assembly <NUM> may include, but is not limited to, the engaged state and the disengaged state.

As explained earlier, based on the operational state of the multi-plate friction clutch assembly <NUM>, the wheels of the vehicle are provided with the drive from the electric motor <NUM>, either from the first gear drive assembly <NUM> or the second gear drive assembly <NUM>. Further, the operational state of the multi-plate friction clutch assembly <NUM> may be selected or actuated based on the speed and the driving load of the vehicle. In an embodiment, the clutch actuation motor <NUM> may be adapted to control the operational state of the multi-plate friction clutch assembly <NUM>. Therefore, based on the speed and the driving load of the vehicle, the controller may control the operation of the clutch actuation motor <NUM> to switch between the operational states of the multi-plate friction clutch assembly <NUM>.

Particularly, the clutch actuation motor <NUM> may be adapted to control the operational state of the multi-plate friction clutch assembly <NUM> with a worm gear pair. The worm gear pair may facilitate self-locking without drawing current to actuator. In an embodiment, a combination of motor clutch cam actuation along with pivot clutch actuation would ensure controlling of the operational state of the multi-plate friction clutch assembly <NUM>.

Further, during reverse gear driving of the vehicle, the one-way clutch assembly <NUM> slips in reverse direction and fails to transmit motion from the input shaft <NUM> to the output shaft <NUM> through the first gear drive assembly <NUM> and the first gear driven assembly <NUM>.

For enabling the reverse gear driving, the transmission system <NUM> may include a drive ratchet <NUM> having an internal spline mounted on the input shaft <NUM>. The transmission system <NUM> may also include a driven ratchet <NUM> adapted to be coupled to the freely mounted first gear drive assembly <NUM>. For enabling reverse gear driving of the vehicle, the drive ratchet <NUM> may be adapted to be engaged with the driven ratchet <NUM>. The engagement of the drive ratchet <NUM> with the driven ratchet <NUM> would enable bypassing of the one-way clutch assembly <NUM>.

In an embodiment, the transmission system <NUM> may include at least one of a rack and pinion mechanism and a solenoid assembly adapted to actuate the engagement of the drive ratchet <NUM> with the driven ratchet <NUM> to drive the vehicle in the reverse gear.

In an embodiment, the transmission system <NUM> may include a position sensor adapted to detect an operational state of the multi-plate friction clutch assembly <NUM>. The position sensor may be in communication with the controller. The controller may be adapted to receive details relating to the speed of the vehicle from the speed sensor, the driving load from the throttle sensor, and the operational state of the multi-plate friction clutch assembly <NUM> from the position sensor. Based on these details, the controller may be adapted to control the engagement of the drive ratchet <NUM> with the driven ratchet <NUM>. In an embodiment, the controller may be adapted to control the operation of the reverse gear actuation system <NUM> to enable the engagement of the drive ratchet <NUM> and the driven ratchet <NUM>.

<FIG> illustrates a magnified front cross-sectional view of the transmission architecture <NUM> depicting operation through the first gear drive assembly <NUM>, according to an embodiment of the present invention. <FIG> illustrates another magnified front cross-sectional view of the transmission architecture depicting operation through the first gear drive assembly <NUM>, according to another embodiment of the present invention. For the sake of brevity, constructional and operational features of the transmission architecture <NUM> that are already explained in the description of <FIG>, <FIG>, and <FIG> are not explained in detail in the description of subsequent figures.

Referring to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, in the present embodiment, the input shaft <NUM> rotates in the drive direction thereby locking the one-way clutch assembly <NUM> in the drive direction. Therefore, the power transmission is established through the one-way clutch assembly <NUM>. In this embodiment, the multi-plate friction clutch assembly <NUM> is in disengaged state and is therefore, slipping. During the transmission in the first gear drive, minimal number of gear meshes are achieved. In the first gear drive, the vehicle is adapted to exhibit high gradeability, i.e., higher payload capacity.

<FIG> illustrates a magnified front cross-sectional view of the transmission architecture <NUM> depicting operation through the second gear drive assembly <NUM>, according to an embodiment of the present invention. <FIG> illustrates another magnified front cross-sectional view of the transmission architecture depicting operation through the second gear drive assembly <NUM>, according to another embodiment of the present invention. Referring to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, in the present embodiment, for the uninterrupted torque transmission, the transmission would be achieved through the second gear drive assembly <NUM>. In the present embodiment, the multi-plate friction clutch assembly <NUM> is in the engaged or the locked state. Further, the one-way clutch assembly <NUM> may be over running owing to higher rotation per minute of the input shaft <NUM>. The vehicle is adapted to achieve the maximum speed while running in the second gear drive.

Figure 6A illustrates a magnified front cross-sectional view of the transmission architecture <NUM> depicting recuperation operation in the first gear drive, according to an embodiment of the present invention. In a recuperation operational mode of the vehicle while driving in the first gear drive, the energy would be recuperated through the first gear drive assembly <NUM>. In this embodiment, the electric motor <NUM> may act as a generator.

<FIG> illustrates a magnified front cross-sectional view of the transmission architecture depicting recuperation operation in the second gear drive, according to an embodiment of the present invention. In the recuperation operational mode of the vehicle while driving in the second gear drive, the energy would be recuperated through the second gear drive assembly <NUM>. In this embodiment, the electric motor <NUM> may act as a generator.

<FIG> illustrates a perspective schematic view and a side schematic view of a portion of the transmission architecture <NUM> depicting operation in a reverse gear drive, according to an embodiment of the present invention. As illustrates, as the electric motor <NUM> rotates in a reverse direction, the drive ratchet <NUM> and the driven ratchet <NUM> are engaged. The driven ratchet <NUM> may be press-fitted on the first gear drive assembly <NUM> and the drive ratchet <NUM> may be slidable on the input shaft <NUM>. The engagement of the drive ratchet <NUM> with the driven ratchet <NUM> is adapted to bypass the one-way clutch assembly <NUM> for reverse gear drive transmission.

Particularly, the ratchet teeth may lock in the reverse direction and slip in the drive direction. In an embodiment, even if the engagement is accidental, the transmission lock is avoided in the drive direction. Therefore, while it is a cost-effective solution, it also ensures functional safety. This would also facilitate anti-theft and hill hold features to the vehicle.

<FIG> illustrates perspective schematic view of the transmission architecture depicting components enabling operation in the reverse gear drive, according to an embodiment of the present invention. The transmission architecture <NUM> may include a ratchet engagement mechanism <NUM> for facilitating the reverse gear drive and immobilizer function to the vehicle. As explained earlier, the ratchet engagement mechanism <NUM> may include, but is not limited to, a rack and pinion mechanism <NUM>.

The transmission architecture <NUM> may also include a ratchet position switch <NUM> adapted to indicate a position of the drive ratchet <NUM> and the driven ratchet <NUM>. Further, the position sensor <NUM> may be adapted to indicate the operational state of multi-plate friction clutch assembly <NUM>. Similarly, the speed sensor <NUM> may be adapted to indicate the speed of the vehicle. Further, the one-way clutch assembly <NUM> and the multi-plate friction clutch assembly <NUM> are shown a combined clutch <NUM> in <FIG>.

Based on the details received from the ratchet position switch <NUM>, the position sensor <NUM>, and the speed sensor <NUM>, the controller may control operation of the ratchet engagement mechanism <NUM> to control the engagement of the drive ratchet <NUM> and the driven ratchet <NUM>.

<FIG> illustrates a schematic representation <NUM> depicting operation of the vehicle in the first gear drive, the second gear drive, and the reverse gear drive, according to an embodiment of the present invention. Further, a graph <NUM> indicates performance of the vehicle in the first gear drive and the second gear drive in case of conventional transmission systems and the proposed transmission architecture <NUM>. The performance is illustrated in terms of traction and speed of the vehicle in the first gear drive and the second gear drive.

<FIG> illustrates a flow chart depicting a method <NUM> of switching gears in the transmission architecture <NUM>, according to an embodiment of the present invention. For the sake of brevity, constructional and operational features of the present invention which are already explained in the description of <FIG> are not explained in detail in the description of <FIG>.

At a block <NUM>, the method <NUM> includes switching ON the electric motor <NUM>. At a block <NUM>, the method <NUM> includes determining whether the throttle is less than a predefined threshold value, for example, <NUM>% of the maximum limit. In an embodiment, when it is determined that the throttle is not less than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes switching the vehicle to the second gear drive. In another embodiment, when it is determined that the throttle is less than the predefined threshold value, the method <NUM> branches to a block <NUM>.

At the block <NUM>, the method <NUM> includes determining whether the vehicle speed is less than predefined threshold value, for example, <NUM> kmph. In an embodiment, when it is determined that the vehicle speed is not less than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes determining whether the reverse gear position is disengaged. In an embodiment, when it is determined that the reverse gear position is not disengaged, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> determines whether the vehicle is in a reverse gear mode. In an embodiment, when it is determined that the reverse gear mode is active, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes actuating the reverse gear drive for the vehicle.

In another embodiment, at the block <NUM>, when it is determined that the reverse gear mode is not active, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes switching ON the actuator mechanism for the multi-plate friction clutch assembly <NUM>. At a block <NUM>, the method <NUM> includes determining whether the multi-plate friction clutch assembly <NUM> is in the engaged state. In an embodiment, when it is determined that the multi-plate friction clutch assembly <NUM> is not engaged, the method <NUM> branches back to the block <NUM>. In another embodiment, when it is determined that the multi-plate friction clutch plate assembly <NUM> is engaged, the method <NUM> branches to the block <NUM>. At the block <NUM>, the method <NUM> includes switching OFF the actuator mechanism of the multi-plate friction clutch assembly <NUM>. The method <NUM> then branches back to the block <NUM>.

Referring back to the block <NUM>, in an embodiment, when it is determined that the reverse gear position is disengaged, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes switching ON the actuator mechanism for the multi-plate friction clutch assembly <NUM>. At a block <NUM>, the method <NUM> includes determining whether the multi-plate friction clutch assembly <NUM> is in the engaged state. In an embodiment, when it is determined that the multi-plate friction clutch assembly <NUM> is not engaged, the method <NUM> branches back to the block <NUM>. In another embodiment, when it is determined that the multi-plate friction clutch plate assembly <NUM> is engaged, the method <NUM> branches to the block <NUM>. At the block <NUM>, the method <NUM> includes switching OFF the actuator mechanism of the multi-plate friction clutch assembly <NUM>. At a block <NUM>, the method <NUM> includes launching the vehicle in the first gear drive.

<FIG> illustrates a flow chart depicting a method <NUM> of recuperation in the transmission architecture <NUM>, according to an embodiment of the present invention. In the present embodiment, the method <NUM> is executed in a fully automatic mode. For the sake of brevity, constructional and operational features of the present invention which are already explained in the description of <FIG> are not explained in detail in the description of <FIG>.

At a block <NUM>, the method <NUM> includes switching ON the electric motor <NUM>. At a block <NUM>, the method <NUM> includes determining whether a deceleration throttle rate is higher than a predefined threshold value. In an embodiment, when it is determined that the deceleration throttle rate is not higher than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes determining whether a brake position travel is less than a predefined threshold value, for example, <NUM>% of the maximum value. In an embodiment, when it is determined that the brake position travel is less than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes a sailing mode of the vehicle in the second gear drive. In another embodiment, at the block <NUM>, when it is determined the brake position travel is not less than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes determining whether the ratchet position is disengaged. In an embodiment, when it is determined that ratchet position is disengaged, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes whether the brake position travel is less than a predefined threshold value, for example, <NUM>% of the maximum value. In an embodiment, when it is determined that the brake position travel is not less than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes activating the recuperation mode of the vehicle in the second gear drive.

In another embodiment, at the block <NUM>, when it is determined that the brake position travel is less than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes determining whether the multi-plate friction clutch assembly <NUM> is in the engaged state. In an embodiment, when it is determined that the multi-plate friction clutch plate assembly <NUM> is engaged, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes activating the recuperation mode of the vehicle in the second gear drive. In an embodiment, when it is determined that the multi-plate friction clutch assembly <NUM> is not engaged, the method <NUM> branches back to the block <NUM>.

At the block <NUM>, the method <NUM> includes switching ON the actuator mechanism for the multi-plate friction clutch assembly <NUM>. At a block <NUM>, the method <NUM> includes determining whether the multi-plate friction clutch assembly <NUM> is in the engaged state. In an embodiment, when it is determined that the multi-plate friction clutch assembly <NUM> is not engaged, the method <NUM> branches back to the block <NUM>. In another embodiment, when it is determined that the multi-plate friction clutch plate assembly <NUM> is engaged, the method <NUM> branches to the block <NUM>. At the block <NUM>, the method <NUM> includes switching OFF the actuator mechanism of the multi-plate friction clutch assembly <NUM>. The method <NUM> then branches back to the block <NUM>.

Referring back to the block <NUM>, when it is determined that the deceleration throttle rate is more than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes determining whether the vehicle speed is less than a predefined threshold value, for example, 25kmph. In an embodiment, when it is determined that the vehicle speed is not less than the predefined threshold value, the method <NUM> branches to the block <NUM>. In another embodiment, when it is determined that the vehicle speed is less than the predefined threshold value, the method <NUM> branches to a block <NUM> and a block <NUM>.

At the block <NUM>, the method <NUM> includes switching ON the actuator mechanism for the multi-plate friction clutch assembly <NUM>. At a block <NUM>, the method <NUM> includes determining whether the multi-plate friction clutch assembly <NUM> is in the engaged state. In an embodiment, when it is determined that the multi-plate friction clutch assembly <NUM> is not engaged, the method <NUM> branches back to the block <NUM>. In another embodiment, when it is determined that the multi-plate friction clutch plate assembly <NUM> is engaged, the method <NUM> branches to the block <NUM>. At the block <NUM>, the method <NUM> includes switching OFF the actuator mechanism of the multi-plate friction clutch assembly <NUM>. The method <NUM> then branches back to a block <NUM>. At the block <NUM>, the method <NUM> includes switching ON the ratchet engagement solenoid. At a block <NUM>, the method <NUM> includes determining whether the ratchet position is engaged. At a block <NUM>, the method <NUM> includes activating the recuperation mode of the vehicle in the first gear drive.

Referring back to the block <NUM>, the method <NUM> includes determining whether the brake position travel is less than a predefined threshold value, for example, <NUM>% of the maximum value. In an embodiment, when it is determined that the brake position travel is less than the predefined threshold value, the method <NUM> branches to the block <NUM>. In another embodiment, when it is determined that the brake position travel is not less than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes determining whether the ratchet position is engaged. In an embodiment, when it determined that the ratchet position is engaged, the method <NUM> branches to the block <NUM>. In another embodiment, when it is determined that the ratchet position is not engaged, the method <NUM> branches to the block <NUM>.

<FIG> illustrates a flow chart depicting a method <NUM> of recuperation in the transmission architecture <NUM>, according to another embodiment of the present invention. In the present embodiment, the method <NUM> is executed in a semiautomatic mode. For the sake of brevity, constructional and operational features of the present invention which are already explained in the description of <FIG> are not explained in detail in the description of <FIG>.

At a block <NUM>, the method <NUM> includes switching ON the electric motor <NUM>. At a block <NUM>, the method <NUM> includes determining whether a deceleration throttle rate is higher than a predefined threshold value. In an embodiment, when it is determined that the deceleration throttle rate is not higher than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes activating the recuperation mode of the vehicle in the second gear drive.

In another embodiment, at the block <NUM>, when it is determined that the deceleration throttle rate is higher than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes determining whether the vehicle speed is less than a predefined threshold value, for example, <NUM> kmph. In an embodiment, when it is determined that the vehicle speed is not less than the predefined threshold value, the method <NUM> branches to a block <NUM>.

At the block <NUM>, the method <NUM> includes determining whether the ratchet position is disengaged. In an embodiment, when it is determined that ratchet position is disengaged, the method <NUM> branches to a block <NUM>.

Referring back to the block <NUM>, in an embodiment, when it is determined that the vehicle speed is less than the predefined threshold value, the method <NUM> branches to a block <NUM>. At the block <NUM>, the method <NUM> includes switching ON the actuator mechanism for the multi-plate friction clutch assembly <NUM>. At a block <NUM>, the method <NUM> includes determining whether the multi-plate friction clutch assembly <NUM> is in the engaged state. In an embodiment, when it is determined that the multi-plate friction clutch assembly <NUM> is not engaged, the method <NUM> branches back to the block <NUM>. In another embodiment, when it is determined that the multi-plate friction clutch plate assembly <NUM> is engaged, the method <NUM> branches to the block <NUM>. At the block <NUM>, the method <NUM> includes switching OFF the actuator mechanism of the multi-plate friction clutch assembly <NUM>. The method <NUM> then branches back to a block <NUM>. At the block <NUM>, the method <NUM> includes switching ON the ratchet engagement solenoid. At a block <NUM>, the method <NUM> includes determining whether the ratchet position is engaged. At a block <NUM>, the method <NUM> includes activating the recuperation mode of the vehicle in the first gear drive.

As would be gathered, the transmission system <NUM> of the present invention offers a comprehensive approach of supplying power to the electric vehicle for achieving increased gradeability and higher top speed. The transmission system <NUM> provides a greater speed and torque range with a smaller electric motor. In addition to this, the two-speed transmission system <NUM> ensures that the electric motor <NUM> operates in highest efficient zones for a greater portion in a selected drive cycle. This further enhances lesser energy consumption. Moreover, the transmission system <NUM> ensures increased payload capacity and gradeability performance without increasing motor or battery size and without compromising vehicle top speed.

The first gear drive is selected to satisfy payload & gradeability requirements of the vehicle while the second gear drive is selected to cater to the maximum vehicle speed. The transmission system <NUM> allows for seamless switching between these two gears without any torque interruption by using the one-way clutch assembly <NUM> and the multi-plate friction clutch assembly <NUM>.

Further, the transmission system <NUM> has the one-way clutch assembly <NUM> and the multi-plate friction clutch assembly <NUM> positioned as the combine clutch on the input shaft <NUM>, which would ensure lower torque. This results in down - sizing both the one-way clutch assembly <NUM> and the multi-plate friction clutch assembly <NUM>, leading to compact size. Further, facilitating reverse gear transmission with ratchets helps in achieving reverse gear functionality in a compact layout. The differential gear pair system is also appropriately positioned on counter shaft <NUM> to bring down the system overall package volume. Therefore, the transmission system <NUM> and therefore, the transmission architecture <NUM> of the present invention are comprehensive, simple in construction and assembly, operation-effective, cost-effective, flexible in implementation, and has a longer service life.

Claim 1:
Two-speed transmission system (<NUM>) for an electric vehicle, the two-speed transmission system (<NUM>) comprising:
a housing (<NUM>);
a first gear drive assembly (<NUM>); and
a second gear drive assembly (<NUM>), characterized by
a one-way clutch assembly (<NUM>) adapted to be mounted on an input shaft (<NUM>) and to be coupled with the first gear drive assembly (<NUM>);
a multi-plate friction clutch assembly (<NUM>) adapted to be mounted on the input shaft (<NUM>) and comprising a clutch hub (<NUM>) disposed in the housing (<NUM>) and mounted on the input shaft (<NUM>);
the second gear drive assembly (<NUM>) freely mounted on the input shaft (<NUM>) and comprising external spline on an outer diameter adapted to be engaged with the clutch hub (<NUM>) of the multi-plate friction clutch assembly (<NUM>),
wherein the one-way clutch assembly (<NUM>) is adapted to rotate to operate the vehicle in the first gear drive when the input shaft (<NUM>) is rotated in a drive direction, and the multi-plate friction clutch assembly (<NUM>) is in a disengaged state when the vehicle is operated in the first gear drive.