FIELD OF INVENTION

[0001] The present invention relates generally to a field of mechanical power transmission, more particularly to a continuously variable transmission hereinafter referred to as an "CVT" system, for use in an automatic transmission for a vehicle or automobile where a step less or a continuously variable transmission is desirable.

BACKGROUND OF INVENTION

[0002] Different types of continuously variable transmission systems have been developed over years for different platforms of applications. Among all, the system applied in the automobile transmission has notably facilitated the scope of automatic transmission. One of the well known applications is the continuously variable transmission by varying the diameter of the pulley in automatic scooters. Although, the invention has revolutionized the automobile market, their performance in terms of power and economy has not been stretched up to their maximum possible potential.

[0003]The U.S Pat No. 6056662 A, discloses a planetary drive mechanism fitted with a brake to transfer variable output either in the forward or reverse, determined upon coupling or decoupling of a flywheel. Out of all methods specified, the common aspect involves application of brake on the planet

1 carrier or feeding input to the planet carrier. In both of the selections, effort required stopping the planet carrier in first case and sun gear in second case is more.

[0004] For example, when sun gear is chosen as input means, and the other sun gear chosen as output means and planet carrier is to be stopped, then the system develops a higher reduction ratio when idling. That is say when 1000 rpm is fed to the sun gear, the speed of planet carrier is going to be 500 rpm, which proves that the torque is amplified by a factor of two at the planet carrier end. Therefore, it is evident that the effort required to stop the planet carrier becomes sufficiently greater.

[0005] Next, if the planet carrier is considered as an input means, one sun gear as an output means and other sun gear as an idler member, the device amplifies speed by almost a factor of two when idling. For example, when a rotational speed of 1000 rpm is fed to the planet carrier, the speed of idler sun gear is around 2000 rpm. This further proves that the effort required to apply brakes is also increased. Furthermore, an external method for reducing braking effort is also explained, which again seems less convincing.

[0006] Further, amongst other existing conventional methods, none conveys any means by which the energy dissipated due to braking could be utilized in some or the other form. With the use of electrical braking to the models,

2 electricity is generated that can be used to charge batteries or capacitors in case of regenerative braking, or converted to heat in case of dynamic braking that can warm up the vehicle interiors.

[0007] U.S. 5,343,970A, explains a hybrid vehicle technology which combines the torque of an Internal Combustion Engine and an electric motor using a Torque transfer unit and a clutch to power the wheels of a vehicle. It has been observed that at lower speeds, only the motor is solely responsible to mobilize the vehicle and is supported by the IC engine only at higher speed range. The patent also does not talk about the condition when the motor is run as a generator in reverse direction by IC engine and then supplying with reverse current would make the motor behave as a brake. When done so, would make an infinitely variable transmission system where the additionally provided clutch pack can be avoided.

[0008] Amidst, the problems of higher reduction ratio acquired by the system during idling, amplification of torque by almost a factor of two, enhanced braking efforts required to stop the system, there remains a necessity to reduce braking effort without requiring an additional set up thereby achieving optimum performance not only in terms of power of engine, but also enhancing powering of wheels of the vehicle.

3 OBJECT OF THE INVENTION

[0009] The primary object of the present disclosure is to provide a continuously variable transmission system using a differential braking mechanism for mechanical power transmission.

[0010] Another object of this disclosure is to provide an infinitely variable transmission with automatic resistance applied to intermediate shaft of the CVT system.

[0011] Yet another object of the disclosure is to minimize or restrict rotation of the intermediate shaft of the CVT system.

[0012] Yet other object of the present disclosure is to provide a braking mechanism to retard the rotation of the intermediate shaft of the CVT system.

[0013] In yet another embodiment, the disclosure provides an optimal method of reducing braking effort required to stop the CVT system without requiring any additional set up and hence additional cost.

[0014] One other object of the present disclosure is to utilize the energy dissipated upon applying the brakes to the system to charge the batteries or the capacitors or converted to heat so as to warm the interiors of the vehicle.

4 [0015] Another object of the present disclosure is to provide optimum power to the wheels of the vehicle by engaging both the motor and the IC engine in generating wider range of speeds, thereby enhancing the utilization and performance of the system in whole.

[0016] In yet another object of the present disclosure, the system is capable of delivering very high output speeds with the electrical setup behaving as a generator in lower speeds and as a motor at higher speeds.

[0017] These and other objects will become apparent from the ensuing description of the present invention.

SUMMARY OF THE INVENTION

[0018] The present invention is directed to a continuously variable transmission system that comprises an input shaft configured to receive a rotational input; an output shaft configured to receive a variable rotational output and an intermediate shaft that is positioned between the input shaft and the output shaft. The continuously variable transmission system further comprises a braking unit that is configured to restrict rotation of the intermediate shaft. Further, a gear arrangement is provided that is configured to receive the rotational input from the input shaft and transmit the variable

5 rotational output to the output shaft based on the restricted rotation of the intermediate shaft.

[0019] In another exemplary embodiment, the continuously variable transmission system comprises a planetary gear type transmission or an epicyclical gear train.

[0020] One preferred embodiment of the disclosure explains the concept of an optimal CVT system employing differential braking where an additional setup for reducing braking effort is not necessary as neither Speed nor torque is sufficiently increased at the braking end.

[0021] These and other aspects, features and advantages of the present invention will be described or become apparent from the following detailed description of preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Fig. 1 shows a block diagram of a generic CVT system having a differential and a braking unit, in accordance with one preferred embodiment of the present disclosure.

6 [0023] Fig. 2 shows a generic schematic view of the planetary gear arrangement in a continuously variable transmission CVT system, in accordance with one preferred embodiment of the present disclosure.

[0024] Fig. 3 illustrates a planetary gear arrangement in a continuously variable transmission CVT system coupled with an external mover, in accordance with one preferred embodiment of the present disclosure.

[0025] Fig. 4 depicts the generic schematic view of the epicyclical gear train in a continuously variable transmission CVT system, in accordance with one preferred embodiment of the present disclosure.

[0026] Fig. 5 illustrates an epicyclical gear train in a continuously variable transmission system coupled with an external mover, in accordance with one preferred embodiment of the present disclosure.

[0027] Fig. 6 illustrates a belt pulley mechanism in a continuously variable transmission CVT system, in accordance with one preferred embodiment of the present disclosure.

7 [0028] Fig. 7 illustrates a planetary gear arrangement in a continuously variable transmission CVT system coupled with an external gear, in accordance with one preferred embodiment of the present disclosure.

[0029] Fig. 8 illustrates a side view of continuously variable transmission CVT system employing a torque converter mechanism, in accordance with one preferred embodiment of the present disclosure.

[0030] Fig. 9 illustrates a side view of another continuously variable transmission system employing a torque converter mechanism with an additional stator shaft, in accordance with one preferred embodiment of the present disclosure

[0031] Fig. 10 illustrates a side view of continuously variable transmission CVT system coupled to an external variator system, in accordance with one preferred embodiment of the present disclosure.

[0032] Fig. 11 illustrates different methods to vary gear ratio and torque ratio of planetary gear arrangement in a continuously variable transmission CVT system.

8 [0033] Fig. 12 illustrates different methods to vary gear ratio and torque ratio of epicyclical gear arrangement in a continuously variable transmission CVT system.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] It has to be understood and acknowledged for this specification and claims, that the term "continuously variable transmission system" refers, though not limiting, to use in an automatic transmission for a vehicle automobile. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present invention, which will be limited only by the appended claims. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. The disclosed embodiments are merely exemplary methods of the invention, which may be embodied in various forms.

[0035] The continuously variable transmission system CVT of the present disclosure includes a braking unit and a centrally positioned gear set up, which is equivalent to an automobile differential, though with a modification.

9 For the purposes of this specification, certain terms have been defined for clarity purposes and shall not be construed limiting in any sense.

[0036] Definitions:

[0037] a) Prime/External Mover: The term herein refers to any external device that acts as a primary source of mechanical input such as an internal combustion or an external combustion engine, or electric motor, etc.

[0038] b) Braking System: It is defined as any arrangement which retards the rotational movement of the control shaft. It can possibly be mechanical, electrical or magnetic braking device or a combination of these.

[0039] c) Input Shaft: It is defined as a shaft to which the external/prime mover is coupled and is responsible for rotational input provided to the CVT system having a differential set up.

[0040] d) Intermediate Shaft: It is defined as a shaft to which a braking device is coupled that controls the output.

[0041] e) Differential Gearing: This refers to the planetary gear arrangement wherein the gear set up uses a pair of first and second gears for its operation to facilitate mechanical power transmission.

10 [0042] The continuously variable transmission system CVT of the present disclosure is more efficient in transmitting mechanical power compared to the systems discussed in the aforementioned background section of the disclosure. The CVT system permits declutching in accordance with one embodiment of the invention while the clutching mechanism is made automatic. Further, neither the speed nor torque is sufficiently increased at the braking end, and the feature of drawing output from the gears amplifies much of the Torque at the actual output end and not at the idler end where braking is necessary.

[0043] Broadly, in accordance with the first embodiment, the continuously variable transmission system CVT 100 comprises an input shaft 10, an intermediate shaft 20, an output shaft 30, a braking unit 40 and a differential gear arrangement 50. The continuously variable system hereinafter, referred to as CVT 100 employs a differential power transmission for mechanical power transmission that enables the output of an external mover 60 to be continuously varied over a range of gear ratios.

[0044] The continuously variable transmission CVT system 100 using the differential and braking system, as shown in Fig. 1 , converts the input rotational force received by the input shaft 10 to a continuously variable output received by the output shaft 30 by varying the load on to the

11 intermediate shaft 20. The CVT system 100 includes a differential gear arrangement 50 that involves meshing of different gears in a certain order where an input shaft 10, output shaft 30 and an intermediate shaft 20 is provided.

[0045] The CVT system 100 of the present disclosure is almost equivalent to an automobile differential but applied in the reverse with an up gradation which reduces the effort required to maneuver the speed of the intermediate shaft 20. In one preferred embodiment, the output obtained at the output shaft 30 is directly proportional to the load acting on the intermediate shaft 20. Therefore, the set up acts as a continuously variable transmission and can be suitably employed in an automobile.

[0046] In one another preferred embodiment, the CVT system 100 comprises a planetary gear type arrangement equivalent to a differential gearbox provided with an input shaft 10, an output shaft 30 and an intermediate shaft 20. The rotational input is coupled to the input shaft 10 and a braking unit 40 is coupled to the intermediate shaft 20.

[0047] In one preferred embodiment of the present disclosure, the CVT system 100 further comprises a pedal or lever 42 that is connected to a braking unit 40 via a transmission line 45. Further, the CVT system 100 comprises a flywheel 48 coupled to the intermediate shaft 20 and the braking

12 unit 40. The rotational output delivered to the output shaft 30 can be varied by altering the extent of resistance or brake applied to the intermediate shaft 20. By adopting different types of braking and gearing arrangements, many embodiments with different functions can be obtained. In one form of the disclosure, the resistance applied to intermediate shaft 20 is made automatic and the system 100 is made to function as an infinitely variable transmission system.

[0048] One preferred embodiment of the disclosure involves the differential gear arrangement 50 of planetary type used in the CVT system 100 fitted with the brake housing as shown in Fig. 2 and Fig. 3. Fig. 2 represents the concept of differential gear arrangement 50 that uses a first pair of gears 52a, 52b and a second pair of gears 54a, 54b. Preferably, the first pair of gears 52a, 52b shares the same axis and can only rotate about it. In one exemplary embodiment, these first pair of gears is bevel gears.

[0049] Next, the second pair of gears 54a, 54b is connected to each other via a common shaft 55 and each of the gear of the second pair is free to spin about the common shaft 55. Further, the second pair of gears 54a, 54b is configured to mesh with first pair of gears 52a, 52b, as shown in Figure 2. In one exemplary embodiment, the pair of secondary gears 54a, 54b is spider gears or planet gears.

13 [0050] In one preferred embodiment, the output shaft 30 is coupled to the common shaft 55 in such a way that their respective axes are perpendicular to each other. Therefore, it is evident that the output shaft 30 rotates only when the common shaft 55 moves, i.e. only when the second pair of gears 54a, 54b revolve around the second gear 52b of the first pair of gears. The first gear 52a of the first pair of gears leads to the input shaft 10 and the other gear 52b of the first pair of gears leads to a hollow intermediate shaft 20.

[0051] It is, however, to be noted that the intermediate shaft 20 and output shaft 30 are concentric shafts and do not have a direct physical contact. Further, the intermediate shaft 20 is provided with a flywheel 48 with which a braking unit 40 is coupled. In one preferred embodiment, the application of brake by the braking unit 40 is designed to restrict the rotation of intermediate shaft 20.

[0052] Referring now to Fig. 3, an instance of a prime/external mover 60 being coupled to the input shaft 10 is provided. Here, the rotational input received from the prime mover 60 by the input shaft 10 is transferred to the first gear 52a of the first pair of gears. Now considering a minimal load on the output shaft 30 and with almost no resistance on intermediate shaft 20, the common shaft 55 is made to remain stationary, thereby causing the

14 secondary pair of gears 54a, 54b to spin only about their positions, which in turn transfers all of the rotational force to the intermediate shaft 20.

[0053] In the above-given configuration, in order to control the extent of braking, a lever or pedal 42 is connected to the braking unit 40 via the transmission line 45. Next, upon depressing the pedal 42, the brake is applied by the braking unit 40, which retards the rotation of intermediate shaft 20. Consequently, the second pair of gears 54a, 54b finding it harder to spin the second gear 54b of the second pair of gears, starts moving around it instead. This shifts the position of common shaft 55 and therefore the rotation is gradually transferred to the output shaft 30.

[0054] It is important to understand that the extent of output delivered to output shaft 30 is directly proportional to the amount of brake applied on the intermediate shaft 20. By applying the maximum level of braking the intermediate shaft 20 comes to a halt and a maximum output is obtained at the output shaft 30.

[0055] Therefore, an additional setup for reducing braking effort is not necessary as neither the Speed nor a torque is sufficiently increased at the braking end. The feature of drawing output amplifies much of the torque at the actual output end (output shaft 30) and not at the idler end (intermediate shaft 20) where braking is necessary.

15 [0056] Now referring to Fig. 4, the same planetary gearing concept is achieved using an epicyclical gear train. Broadly, the epicyclical gear train comprises a ring gear 56, athird pair of gears 58a, 58b and a centrally located gear 57. The ring gear 56 is an internal or annular gear that meshes with a third pair of gears 58a, 58b that further meshes with a centrally located gear 57. Preferable, the third pair of gears 58a, 58b is the planetary gears and the central gear 57 is a sun gear.

[0057] As can be seen in Fig. 4, an arm 59a connects the ring gear 56 to the input shaft 10 and an arm 59b connects the third pair of gears 58a, 58b to the output shaft 30. The central gear 57 leads to a hollow intermediate shaft 20 provided with a flywheel 48 with which the braking unit 40 is coupled. Here again the output shaft 30 and the intermediate shaft 20 are concentric in nature having no direct physical contact.

[0058] Therefore, when a prime mover 60 is coupled to an input shaft 10 of the mentioned gear train, the ring gear 56 rotates. Now, assuming a minimal load on the output shaft 30 and no resistance on intermediate shaft 20, the third pair of gears 58a, 58b just spins at their respective positions. Thus, the output is obtained only at the intermediate shaft 20. With the application of brake, the third pair of gears 58a, 58b tends to revolve around the central

16 gear 57 causing the arm 59b to move, thereby transferring the variable output to the output shaft 30.

[0059] The concept of using an epicyclical gear train at an instance of a prime/external mover 60 coupled to the input shaft 10 is provided, as shown in Fig. 5. Here, it is to be further noted that in case the speed of rotation of the prime mover 60 is made adjustable using a control lever or throttle, then the braking can also be controlled using the same provision. While done so, depressing of such a lever or pedal 42 causes the speed of prime mover 60 to increase and the brake on intermediate shaft 20 also gets simultaneously initiated.

[0060] FIRST MODIFICATION EXAMPLE

[0061] While different methods can be used to draw the output from the CVT system 100, in one preferred embodiment, as shown in Fig. 6, the final transmission can be achieved using a belt and pulley mechanism. Re- referring to Fig. 6, the pulley 62 is rigidly coupled to a common shaft of the planetary type differential gear arrangement 50 and acts as a driver. On the other hand, the driven pulley 64 is fixed to output shaft 30. The belt element 63 runs between the driver pulley 62 and the driven pulley 64.

[0062] SECOND MODIFICATION EXAMPLE

17 [0063] Likewise, a chain sprocket arrangement can also be made where the belt element 63 refers to a chain, driver pulley 62 acts as the driver sprocket and driven pulley 64 acts as the driven sprocket. The same methods of obtaining output can also be applied for epicyclical version of system 100.

[0064] THIRD MODIFICATION EXAMPLE

[0065] In one other exemplary embodiment, as shown in Fig 7, the common shaft 55 of the planetary type gear arrangement can be coupled to an external gear 70 that drives the output gear 72. Similar concept can also be employed for the epicyclical type of gear arrangement.

[0066] FOURTH MODIFICATION EXAMPLE

[0067] Referring now to Fig. 8, a design of the above discussed CVT system 100 that is similar to a Hydraulic torque converter, is presented. As will be acknowledged by those skilled in the art, the Hydraulic torque converters have an outer shell that is generally connected to an engine flywheel having a protruding tube at the other end which drives the gear pump that supplies oil for the gearbox. Therefore, the gear pump functions as long as the engine runs. The main output shaft of the torque converter is positioned concentric to the tube structure separated with a gap.

18 [0068] The similar model adopted in the discussed concept is shown by Fig 8, which is representative of the side view of the CVT system 100. The planetary gear train is enclosed by joining two half casings 82 and 84 together. The casing 82 is provided with an input shaft 10 and the casing 84 leads to the hollow shaft 20 at the other end. The output shaft 30 is concentric to the hollow shaft 20, but is separated with a gap, as explained earlier in the description.

[0069] As can be best seen and understood from Fig. 8, the ring gear 56 is fixed to the casing 82 and arm 59b connects the third pair of gears 58a, 58b with each other. An important feature here is that the brake system designed to resist the motion of intermediate shaft 20 is rigidly fixed to the casing 84 and is never stationary i.e. the brake shoes run in the direction of the prime mover 60, and opposite to that of the intermediate shaft 20 when the prime mover 60 is running.

[0070] Now, as the brake housing itself rotates, the conventional drum or disc braking methods with an external control mechanism are not usable here as the brake shoes are always in motion. This stresses upon the need for automatically engaging brakes like centrifugal brake system. The only external control mechanism possible is by hydraulically controlling pressure of a fluid through the gap between the output shaft 30 and the outer tube around

19 it. If electrical brake system is to be used, then "brake by wire technology" can be adopted where a brush type contact is necessary.

[0071] As the prime mover 60 is switched on, the rotational force is transferred to the ring gear 56, and the casing 82 and 84 start rotating with it. This causes the third pair of gears 58a, 58b to spin at their positions as they consecutively spin the central gear 57 in an opposite direction. But since the braking unit 40 is fixed to the casing 84, it is set in motion and in a direction opposite to the direction of rotating intermediate shaft 20. When the brake system is actuated, the running brake shoe comes in contact with the flywheel 48 of the intermediate shaft 20 that is running in reverse. As the friction develops, the flywheel 48 slows down and as it becomes almost stationary, the system 100 delivers an output with a gear ratio that the planetary gear is designed with.

[0072] With further application of brake and with more friction, the rotating brake shoes start transferring torque on to the flywheel 48 causing it to rotate in the direction of the fed input. This further increases the speed of output shaft 30. When the brake is applied to the full, and assuming no slippage between the brake shoe and flywheel 48, the third pair of gears 58a, 58b do not spin and the speed of ring gear 56 becomes equal to the speed of the central gear 57. At this particular stage, the speed of output shaft 30 is equal

20 to the speed of input shaft 10 and the gear ratio of system 100 becomes 1 :1 with negligible power loss.

[0073] In one preferred configuration, the above described phenomena can be automated by using centrifugal brake system or eddy current brake system where the braking effect is directly proportional to speed.

[0074] FIFTH MODIFICATION EXAMPLE

[0075] Next, in order to enable the use of conventional brake systems and their regular control mechanisms a stator shaft 75 with its flywheel 76 is additionally provided, to which the braking unit 40 is attached, as depicted by Fig 9. By doing so, the braking unit 40 always remains stationary. Further, the control lines cable or hydraulic hose can run along the stator shaft 75.

[0076] Referring now to Fig. 10, in order to optimize the concept and automate the on and off of brake, a variator system 90 can also be positioned next to the differential braking system 40, in one exemplary embodiment. The variator system 90 can be any system that alters the braking effect depending upon the fed speed. For instance, when a roller weight variator is used and a higher speed is fed to the system 100, the rollers are configured to move apart due to centrifugal force, pushing a mating shoe against a running disc to increase friction. But when there is no sufficient centrifugal force to move

21 the rollers or weights apart, there would be no braking effect. Hence, the transmission occurs only upon accelerating the prime mover 60.

[0077] It is obvious for a skilled person in the art to acknowledge that the fourth and fifth modification examples are also applicable for the differential gear arrangement 50 using first pair of gears 52a, 52b and second pair of gears 54a, 54b. Here it is clear that the half casing 82 is to be connected to gear 52a and other half casing 84 fixed with braking unit 40 designed to retard intermediate shaft 20.

[0078] Next, different methods that can be used to change the gear ratio of the system 100 by varying the number of teeth of meshing gears, as depicted in Figs. 11 and 12. For example, Fig 11 (i) shows all the meshing gears having equal number of teeth.

[0079] Fig 11 (ii) shows the gears other than planet gears having unequal number of teeth.

[0080] Fig 1 1(iii) shows the system 100 in which the number of teeth on planet gears is higher than that of the other two bevel gears.

[0081] Fig 1 (iv) shows the planet gears having smaller number of teeth compared to the other two bevel gears.

22 [0082] Fig 11 (v) shows a similar configuration in which two sets of planet gears are used, where one set has a greater number of teeth compared to the other. The two planet gears of different sizes are fixed to each other as shown in Fig 11 (v). Therefore the smaller planet gear rotates with the larger planet gear connected to it. As the bevel gear to which the braking unit 40 is to be coupled meshes with the smaller set of planet gears, a lower effort is required for braking.

[0083] Fig. 12(i) shows the epicyclical gear train used for the system 100 having planet gears smaller than the sun gear.

[0084] Fig. 12(ii) shows the gear train in which the planet gears and a central sun gear are of same size.

[0085] Fig. 12(iii) shows the form in which the planet gears are larger than the central sun gear.

[0086] In one exemplary embodiment, possible types of braking that can be applied to the present CVT system 100 is described. Majorly, three types of braking can be applied by the braking unit 40 i.e. centrifugal braking, simple magnetic braking, electrical braking and eddy current braking.

23 [0087] The electrical braking, for instance is made feasible when the intermediate shaft 20 integrated with an electric motor structure with necessary circuit connections for the below mentioned types of braking:

[0088] i) Rheostatic or dynamic braking

[0089] ii) Reverse current braking - By supplying reverse current to the coils, the running intermediate shaft 20 is slowed down initially causing it to come to a halt and by continuing the reverse current supply further causes the intermediate shaft 20 to spin in a direction opposite to its earlier rotational direction i.e. in the direction of rotating input. It, thus, acts as a secondary input causing the output to multiply further.

[0090] Thus, the system 100 is capable of delivering very high output speeds as the electrical setup behaves as a generator in lower speeds and as a motor at higher speeds. It is an ideal stage in which the electrical system on the intermediate shaft 20 acts as a motor supporting the other prime mover 60 in providing an increased output. This would produce a new version of electrically controlled Continuously Variable Transmission E-CVT.

[0091] With the use of reverse current braking in hybrid vehicle technology where present CVT system 100 using braking unit 40 is used, the power sharing range of the two prime movers is broadened as it combines the

24 torque of say an Internal Combustion Engine and an electric motor to power the wheels of a vehicle. Thus, the motor and IC engine share their work for a wider range of speeds and so they are utilized better.

[0092] During idling operation, a reverse current supplied to the coils resist the motion of idling gear causing the partial power of IC engine to shift to the output until the idler gear rotation is stopped completely. When it comes to a total halt, all of the power of engine is delivered to the output. Now by continuing the supply of reverse current, the idle gear starts rotating in a direction opposite to its earlier direction of rotation. In other words, the electrical system or braking setup no longer behaves as a brake but starts to work as a motor, supporting the IC engine in powering wheels. Also an additional generator can be coupled to IC engine, for an all time power generation.

[0093] iii) Regenerative braking

[0094] Thus, from the above description, it is sufficiently understood that the present CVT system 100 having braking unit 40 is equivalent to an automobile differential, though with a modification. The one feature that would distinguish the present CVT system 100 with conventional automobiles open differential is the additional set of spider or planetary gears which causes

25 torque reduction when output is delivered to the intermediate shaft 20, which facilitates effortless braking of the intermediate shaft 20.

[0095] The foregoing description is a specific embodiment of the present disclosure. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

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