Description:
FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[SEE SECTION 10, RULE 13]

A TRANSMISSION SYSTEM FOR A VEHICLE

MAHINDRA & MAHINDRA LIMITED, MAHINDRA RESEARCH VALLEY, MAHINDRA WORLD CITY, PLOT NO:41/1, ANJUR P.O., CHENGALPATTU, TAMILNADU – 603004.

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED. 

TECHNICAL FIELD
[001] The present invention relates to a transmission system for a motor vehicle having a gearbox that introduces modularity between a 6-speed manual gearbox and an 8- speed automated manual transmission (AMT).

BACKGROUND
[002] Generally, selection a power transmission unit in a vehicle is used for transmitting torque from an engine or an electric motor to the wheels of the vehicle for propelling the vehicle and for increasing and decreasing the speed of the vehicle.
[003] Referring Figure 1 illustrates a conventional manual 6-speed gearbox (100) having an input shaft (110) that receives power from an engine of a vehicle. The gearbox (100) has 6 gears for forward drive and a reverse gear connected to idler gear mounted on countershaft for reverse drive. The input shaft (110) is coupled to an output shaft (120) of the gearbox (100) via a countershaft (130). A hub (140) has a plurality internal and external spline. Internal spline connects the hub (140) to the output shaft (120). When output shaft (120) rotates taking power from input shaft (110), the hub (140) rotates and vice versa. The external spline of the hub (140) is connected to a sleeve (150). When the hub (140) rotates, the sleeve (150) rotates and vice versa. The sleeve (150) has plurality of external grooves on which a fork pad (160) is mounted. When the fork (160) is translated to shift a gear (105), the fork (160) translates the sleeve (150) through a synchro ring (170) which synchronizes speed between a clutch body ring (180) and the sleeve (150). The clutch body ring (180) is always welded/ integrated to the gear (105) and always rotate at the speed of gear (105). When the gear (105) is engaged, the fork (160) connects the sleeve (150) to the clutch body ring (180) through the synchro ring (170). Referring Figure 1, power flow happens from the gear (105) to the clutch body ring (180), from the clutch body ring (180) to the sleeve (150) and from the sleeve (150) to the hub (140) and from the hub (140) to the output shaft (120).
[004] In such conventional gearbox (100), the transmission is manual and of only 6-speed. With growing technology, clutch-less automated manual transmission vehicles (AMT) are in demand. AMT transmission vehicles have good speed with ease of transmission. The automated manual transmission does not change gears automatically but facilitates manual gear changes without the need to depress the clutch pedal manually. The existing manual transmission systems cannot be readily employed in various standard AMT transmission systems. To meet the growing demand separate manufacturing lines for AMT gearbox production are required. Thus, cost to optimize for separate manufacturing lines, design, development, and validation of such AMT gearbox is significantly expensive. Another limitation is installation of such separate production line is time consuming.
[005] Therefore, there is a need for a solution for a transmission system to address and overcome one or more problems of the prior art.

SUMMARY
[006] This summary is provided to introduce concepts related to a transmission system for a vehicle. This summary is neither intended to identify essential features of the present invention nor is it intended for use in determining or limiting the scope of the present invention.
[007] Accordingly, an aspect of the present invention discloses a transmission system for a vehicle, said transmission system comprising: a modular gearbox for multi-speed having: an input drive shaft for receiving a drive force from an engine; a first output shaft having splined with said input drive shaft, located colinear to said input drive shaft for freely outputting rotational power of said first output shaft; an input shaft gear mounted on said first output shaft splined with said input drive shaft for freely outputting rotational power of said input shaft gear; a countershaft located spaced apart and parallel to said first output shaft, said first output shaft coupled with said countershaft via a plurality of forward multi-speed drive gears and driven gears externally connected to each other for selectively establishing a power transmission path when actuated by a plurality of solenoid valves, at least said forward multi-speed drive gears and driven gears mounted on said countershaft; a second output shaft located colinear to said first output shaft and parallel to said countershaft, said second output shaft coupled to said countershaft via a plurality of forward multi-speed final drive (FD) gears and final driven gears externally connected to each other for selectively establishing a power transmission path in meshing combination with at said forward multi-speed drive gears and driven gears when actuated by said plurality of solenoid valves; and a reverse gear mounted on second output shaft coupled via an idler gear mounted on said countershaft for reverse drive speed, thereby converting a 6-speed manual gearbox to an 8-muti-speed automated manual transmission (AMT) of said modular gearbox with no change in a size of said modular gearbox.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[008] The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:
[009] Figure 1 illustrates a cross-sectional detailed layout view of a conventional 6-speed manual gear;
[0010] Figure 2 illustrates a cross-sectional detailed layout view showing the exemplary indicative implementation of modular 8-speed AMT gearbox of the transmission system, according to an aspect of the present invention;
[0011] Figure 3 illustrates a line diagram view showing gear arrangement layout in the exemplary indicative implementation of the modular 8-speed AMT gearbox of the transmission system, according to the embodiment of the present invention;
[0012] Figure 4 illustrates a power flow layout in forward drive condition in the exemplary indicative implementation of the modular 8-speed AMT gearbox of the transmission system, according to the embodiment of the present invention; and
[0013] Figure 5 illustrates a power flow layout in reverse drive condition in the exemplary indicative implementation of the modular 8-speed AMT gearbox of the transmission system, according to the embodiment of the present invention.
[0014] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION
[0015] In the following description, for the purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known structures are shown in diagram form to facilitate describing the invention. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into several applications.
[0016] In general, the present invention claims a transmission system for a vehicle comprising a modular gearbox for multi-speed having: an input drive shaft, a first output shaft having splined with said input drive shaft, an input shaft gear mounted on said first output shaft splined with said input drive shaft, a countershaft located spaced apart and parallel to said first output shaft, said first output shaft coupled with said countershaft via a plurality of forward multi-speed drive gears and driven gears externally connected to each other for selectively establishing a power transmission path when actuated by a plurality of solenoid valves, a second output shaft located colinear to said first output shaft and parallel to said countershaft, said second output shaft coupled to said countershaft via a plurality of forward multi-speed final drive (FD) gears and final driven gears externally connected to each other for selectively establishing a power transmission path in meshing combination with at said forward multi-speed drive gears and driven gears when actuated by said plurality of solenoid valves, thereby converting a 6-speed manual gearbox to an 8-muti-speed automated manual transmission (AMT) of said modular gearbox with no change in a size of said modular gearbox.
[0017] According to the present invention, a 6-speed manual gearbox may be converted to an 8-speed automated manual transmission. With the teachings of the present invention, the requirement of separate manufacturing lines for AMT gearbox production is eliminated as the modular gearbox of the present invention is configured to achieve a commonality between manual and AMT gearboxes. The complete cost and time to develop AMT gearbox is significantly reduced. The AMT gearbox having 8-speed is obtained from any conventional 6-speed gearbox without making any changes in the size of the gearbox. Therefore, the present invention eliminates additional parts that include gears, sleeves, hubs and change in layout for converting into 8-speed AMT gearbox.
[0018] According to the present invention, a gear shifter fork refers a lever with a forked end that slides gears into or out of engagement with other gears to change gear ratios in said gearbox.
[0019] While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail, a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspects of the invention to the embodiment illustrated. Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
[0020] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. The skilled person will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present invention. All the terms and expressions in the description are only for the purpose of the understanding and nowhere limit the invention. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein may be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness. Terms first, second, third, fourth, fifth, sixth, seventh, eighth, front, rear, left, right, horizontal, vertical, parallel, perpendicular, synchro pack and the like are used to differentiate between objects having the same terminology and are in no way intended to represent a chronological order, unless where explicitly stated otherwise. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.
[0021] Referring figures 2-5, discloses a modular gearbox (200), a countershaft (210), an input drive shaft (205), a hub (212), a synchro ring (214), a first output shaft (215), a sleeve (216), a shift fork (218), a second output shaft (220), an input shaft gear (225), a 3rd and 4th gear synchro pack (230), a plurality of final drive FD gear synchro pack (235), an intermediate pate (240), a fourth gear (250), a third gear (255), a second gear (260), and a first gear (265), a first final drive FD gear (270), a second final drive gear (275), and a reverse gear (280).
[0022] Accordingly, the present invention discloses a transmission system for a vehicle. A modular gearbox (200) for multi-speed has an input drive shaft (205) for receiving a drive force from an engine. A first output shaft (215) is splined with said input drive shaft (205) and is located colinear to said input drive shaft (205) for freely outputting rotational power of said first output shaft. An input shaft gear (225) is mounted on said first output shaft (215) is splined with said input drive shaft (205) for freely outputting rotational power of said input shaft gear. A countershaft (210) is located spaced apart and parallel to said first output shaft (215). The first output shaft (215) is coupled with said countershaft (210) via a plurality of forward multi-speed drive gears and driven gears (250, 255, 260, 265) externally connected to each other for selectively establishing a power transmission path when actuated by a plurality of solenoid valves. According to an embodiment, at least said forward multi-speed drive gears and driven gears (250, 255) are mounted on said countershaft (210).
[0023] According to the embodiment, a second output shaft (220) is located colinear to said first output shaft (215) and is parallel to said countershaft (210). The second output shaft (220) is coupled to said countershaft (210) via a plurality of forward multi-speed final drive (FD) gears and final driven gears (270, 275) externally connected to each other for selectively establishing a power transmission path in meshing combination with at said forward multi-speed drive gears and driven gears (250, 255, 260, 265) when actuated by said plurality of solenoid valves, thereby converting a 6-speed manual gearbox (100) to an 8-muti-speed automated manual transmission (AMT) of said modular gearbox (200) with no change in a size of said modular gearbox (200).
[0024] According to the embodiment, a reverse gear (280) is mounted on second output shaft (220) and is coupled via an idler gear mounted on said countershaft (210) for reverse drive speed.
[0025] According to the embodiment, said power transmission path established includes power flow from at least a gear (260, 265) mounted on said first output shaft (215) or at least a gear (250, 255) mounted on said countershaft (210) connected via at least a synchro pack fork (218), when power flow from said input shaft gear (225) is coupled with at least a mating gear, at least said mating gear interconnected with at least a synchro pack (235), each said synchro pack (235) having at least a clutch body ring coupled to at least a sleeve (216), said at least sleeve (216) interconnected to at least a hub (212) splined to said first output shaft (215) or said countershaft (210) connecting with at least said gear (250, 255, 260, 265).
[0026] According to the embodiment, said power transmission path established includes power flow from at least a first and second final drive gears (270, 275) (FD) mounted on the countershaft (210) coupled to at least said synchro pack (235), each said synchro pack (235) having at least said hub (212) splined to said countershaft (210) or said second output shaft (220) coupled to at least said sleeve (216) engaged with at least said clutch body ring meshed to at least said mating gear splined to said second output shaft (220) for rotation of said second output shaft (220).
[0027] According to the embodiment, at least said hub (212) has external and internal splines connecting said countershaft (210) and said first and second output shafts (215, 220), and at least said sleeves (216) has external and internal splines connecting at least said hub (212) and at least said gear (250, 255, 260, 265, 270, 275).
[0028] According to the embodiment, at least said synchro pack (235) is mounted intermediate at least said gears (250, 255, 260, 265, 270, 275), each said synchro pack (235) is actuated axially displacing from a normal position to an engaged position for engaging at least said gears (250, 255, 260, 265, 270, 275).
[0029] According to the embodiment, said plurality of actuating solenoid valves includes a first solenoid valve connected to a 1st, 2nd synchro pack gear shifting fork (218), a second solenoid valve connected to a 3rd, 4th synchro pack gear shifting fork (218), a third solenoid valve connected to a first and second final drive (270, 275) synchro pack gear shifting fork (218) and a fourth solenoid valve connected to a reverse gear shifting fork (218).
[0030] According to the embodiment, said 1st, 2nd, 3rd, and 4th synchro pack gear shifting forks (218) are operatively coupled to a gear lever for selectively shifting an input torque depending on the respective gear ratios of said plurality of driving and driven gears (250, 255, 260, 265) outputting the shifted torque through said first output shaft (215) to said countershaft (210) when said forks (218) engage splined hubs (212) and gear sleeves (216) and synchro rings (214) of said gears (250, 255, 260, 265) in the axial direction establishing power transmission path displacing said driving and driven gears (250, 255, 260, 265) on respective first output shaft (215) and said countershaft (210) in combination with said first final drive (270) and second final drive (275) gears on said countershaft (210) to said second output shaft (220) in said forward multi-speed drive.
[0031] According to the embodiment, said drive and driven gears (250, 255, 260, 265) for rotation include a first (265) and a second (260) drive gear coupled on said first output shaft (215) and a first (265) and a second (260) driven gear mounted on said countershaft (210) selectively meshed with said first final drive gear (270) or second final drive gear (275) mounted on the countershaft (210), said final drive gears (270, 275) coupled to said final driven gears (270, 275) mounted on the second output shaft (220) to output power in said forward multi-speed drive.
[0032] According to the embodiment, said drive and driven gears for rotation include a third (255) and a fourth (250) driven gear coupled on said countershaft (210) selectively meshed with said first final drive gear (270) or second final drive gear (275) mounted on the countershaft (210), said final drive gears (270, 275) coupled to said final driven gears (270, 275) mounted on the second output shaft (220) to output power in said forward multi-speed drive.
[0033] According to the embodiment, said first and second gears (265, 260) mounted on said first output shaft (215) are located left side of an intermediate pate (240) and said third and fourth gears (255, 250) mounted on said second output shaft (220) are located left side of an intermediate pate (240) at a first portion of said countershaft (210) and first final drive gear FD (270) and second final drive gear FD (275) are located on right side of said intermediated plate at a second portion of countershaft (210), and said reverse gear (280) mounted on second output shaft (220) on said right side of said intermediated plate at said second portion of countershaft (210).
[0034] Referring to Figure 2, illustrates a cross-sectional detailed layout view showing the exemplary indicative implementation of modular 8-speed AMT gearbox of the transmission system, according to an aspect of the present invention. The present invention discloses conversion of 6-speed manual gearbox to 8- speed modular gearbox AMT. The modular gearbox (200) consists of countershaft (210), an input shaft (205) splined to a first output shaft (215). The first output shaft is configured to free rolling on a second output shaft (220). An input shaft gear (225) is splined to the first output shaft (215). In the modular gearbox, because of the splined input shaft gear (225), a 3rd and 4th gear synchro pack (230) mounted on the countershaft (210). The gear layout also includes a plurality of final drive FD gear synchro pack (235) having gears FD1 and FD2 respectively mounted on the countershaft (210). The modular gearbox layout requires two mechanisms to engage a specific gear synchro pack and the FD gear synchro pack in a forward drive condition. In the modular gearbox layout input gear (205) always rotates as it is connected to the engine source through a clutch. Since the input gear (205) is in mesh with 3rd and 4th mating gear synchro pack (230) mounted on the countershaft (210) when engaged, 3rd and 4th mating gear synchro pack (230) freely rotate having located on a needle roller bearing.
[0035] Referring to Figure 3 illustrates a line diagram view showing gear arrangement layout in the exemplary indicative implementation of the modular 8-speed AMT gearbox of the transmission system, according to the embodiment of the present invention. The line diagram of the modular gearbox (200) comprises first output shaft (215), a second output shaft (220), an intermediate pate (240). A fourth gear (250), a third gear (255), a second gear (260), and a first gear (265) are located to a left side of the intermediate pate (240). The four gears (250, 255, 260, 265) are multiplied by two to obtain 8 different gear ratios, while it passes through two final drive FD gears (270, 275) on the right side of the intermediate plate (240). For example: The modular gearbox has the following 8 gear speed ratios: first speed has a combination of first gear (265) and first final drive gear (270). Second speed has combination of first gear (265) and second final drive gear (275). Third speed has a combination of second gear (260) and first final drive gear (270). Fourth speed has a combination of second gear (260) and second final drive gear (275). Fifth speed has a combination of third gear (255) and first final drive gear (270). Sixth speed has a combination of third gear (255) and second final drive gear (275). Seventh speed has a combination of fourth gear (250) and first final drive gear (270). Eighth speed has combination of fourth gear (250) and second final drive gear (275). The modular gearbox (200) also has a reverse gear (280) on the right side of the intermediate plate (240) connected to the idler gear mounted on countershaft. The reverse gear (280) has a combination of fourth gear (250) and reverse gear (280).
[0036] Referring Figure 4 illustrates a power flow layout in forward drive condition in the exemplary indicative implementation of the modular 8-speed AMT gearbox of the transmission system, according to the embodiment of the present invention. According to the embodiment, the present invention converts 5th & 6th gears in the manual gearbox connected to output shaft to first final drive gears FD1 (270) and second final drive gear FD2 (275) in AMT. The gear layout in present invention has two output shafts and solenoid valves mounted outside the gearbox for actuation of the gears. In the present invention, shift actuation of the gears is controlled through a plurality of solenoid valves. The modular gear AMT gearbox (200) has at least four solenoid valves, each packaged outside the gearbox and connected to at least a shift fork (218).
[0037] According to the embodiment of the present invention, a first solenoid valve is connected to the 1st, 2nd synchro pack fork (218). A second solenoid valve is connected to the 3rd, 4th synchro pack fork (218). A third solenoid valve is connected to first and second final drive synchro pack fork (218). A fourth solenoid valve is connected to the reverse gear fork.
[0038] In the present invention, during the forward drive condition, the third solenoid valve always connects along with solenoid 1 or solenoid 2. The solenoid valve combination is first solenoid valve and third solenoid valve or second solenoid valve and third solenoid valve. During reverse drive condition, fourth solenoid valve and second solenoid valve are connected.
[0039] According to the embodiment of the present invention in the forward drive condition, when a gear is engaged, for example a 7th gear is engaged 3rd, 4th synchro pack fork (218) connects the sleeve to a 4th clutch body ring of a mating gear through the synchro ring (214). The power flows through input shaft gear (205) to the mating gear (250), from the mating gear (250) to a clutch body ring, from a clutch body ring to sleeve (216), from sleeve (216) to the hub (212) and from hub to the countershaft (210). As final drive FD synchro pack (235) is mounted on the countershaft (210), power continues to flow from countershaft (210) to hub (212) and to sleeve (216) and then to engaged clutch body ring and to engaged gear. As the engaged first final drive FD gear (270) is in mesh with mating gear splined to the second output shaft (220), the output shaft (220) rotates.
[0040] According to another embodiment, the present invention discloses a method of providing power flow in the transmission system, the method includes allowing power flow from an input drive shaft splined to a first output shaft to a countershaft through at least an input driving gear connected to the first output shaft or at least an input driving gear connected to the countershaft and at least an input driven gear mounted to the countershaft or at least an final drive gear mounted on the countershaft and at least a driven gear mounted on second output shaft, by engaging a plurality of movable gear shift fork members selectively depending upon respective gear ratio and speed with the respective gear sleeve and hubs of a synchro pack of said gears.
[0041] Referring Figure 5 illustrates a power flow layout in reverse drive condition in the exemplary indicative implementation of the modular 8-speed AMT gearbox of the transmission system, according to the embodiment of the present invention. According to the embodiment of the present invention in the reverse drive condition, when a reverse gear (280) is engaged 3rd, 4th synchro pack fork (218) connects the sleeve to a 4th clutch body ring of a mating gear through the synchro ring (214). The power flows through input shaft gear (205) to the mating gear (250), from the mating gear (250) to a clutch body ring, from a clutch body ring to sleeve (216), from sleeve (216) to the hub (212) and from hub to the countershaft (210). The Reverse drive gear (280) is splined to the countershaft (210) and therefore the reverse drive gear (280) rotates. The reverse gear (280) is in mesh with an idler gear mounted on countershaft that is in mesh with the reverse driven gear (280) on the second output shaft (220). When a reverse synchro pack is also engaged through an actuating mechanism that translates the fork to connect sleeve and reverse clutch body ring, power flows from reverse drive gear (280) to reverse idler and to reverse driven gear and to reverse clutch body ring and to sleeve (216) and to hub (212) and finally second output shaft (220). The actuating mechanism includes plurality of solenoid valves.
[0042] Thus, with the teachings of the present invention, any 6-speed manual gearbox may be converted to 8-speed AMT gearbox without change in the size of the gearbox. The requirement of separate manufacturing lime for AMT gearbox is eliminated. The layout of the manual gearbox is modified. The output shaft is divided to two shafts, 3rd, 4th synchro pack is located and coupled on the countershaft and plurality of solenoid values are employed for shift actuation of gears.
[0043] There have been described and illustrated herein several embodiments of exemplary indicative implementation of the transmission system having a gearbox that introduces modularity between a 6-speed manual gearbox and an 8- speed automated manual transmission (AMT). It will be also apparent to a skilled person that the embodiments described above are specific examples of a single broader invention, which may have greater scope than any of the singular descriptions taught. There may be many alterations made in the description without departing from the scope of the invention. The present invention is simple in construction and design, integrated, cost effective and easy to manufacture. While particular embodiments of the invention have been described, it is not intended that the invention be limited said configuration disclosed thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while particular structure specific type of arrangement of gears, sleeves, synchro rings, clutch body rings, number, speed of gears, final drive gears, reverse gears, and actuating mechanisms like solenoid valves have been disclosed, it will be appreciated that the embodiments may be manufactured with other design parameters and configurations as well. Accordingly, the number and arrangement of gear, shafts, are not limited thereto and may be as per operational requirements and nowhere limits the scope of the invention. Known materials may be used for the components of the transmission system and modular gearbox as per operational requirements and nowhere limits the scope of the invention. Thus, while particular structure with said configurations has been disclosed, it will be appreciated that the embodiments may be manufactured with other design parameters as well. Further, the methods and configuration of the system, are provided only for reference and for understating purpose of the invention. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” is used as the plain-English equivalent of the respective term “comprising” respectively.
, C , Claims:
1. A transmission system for a vehicle, said transmission system comprising:
a modular gearbox (200) for multi-speed transmission having:
an input drive shaft (205) for receiving a drive force from an engine;
a first output shaft (215) having splined with said input drive shaft (205), located colinear to said input drive shaft (205) for freely outputting rotational power of said first output shaft (215);
an input shaft gear (225) mounted on said first output shaft (215) splined with said input drive shaft (205) for freely outputting rotational power of said input shaft gear (225);
a countershaft (210) located spaced apart and parallel to said first output shaft (215), said first output shaft (215) coupled with said countershaft (210) via a plurality of forward multi-speed drive gears and driven gears (250, 255, 260, 265) externally connected to each other for selectively establishing a power transmission path when actuated by a plurality of solenoid valves, at least said forward multi-speed drive gears and driven gears (250, 255) mounted on said countershaft (210);
a second output shaft (220) located colinear to said first output shaft (215) and parallel to said countershaft (210), said second output shaft (220) coupled to said countershaft (210) via a plurality of forward multi-speed final drive (FD) gears and final driven gears (270, 275) externally connected to each other for selectively establishing a power transmission path in meshing combination with at least said forward multi-speed drive gears and driven gears (250, 255, 260, 265) when actuated by said plurality of solenoid valves; and
a reverse gear (280) mounted on second output shaft (220) coupled via an idler gear mounted on said countershaft (210) for reverse drive speed, thereby converting a 6-speed manual gearbox (100) to an 8-muti-speed automated manual transmission (AMT) of said modular gearbox (200) with no change in a size of said modular gearbox (200).

2. The transmission system as claimed in claim 1, wherein said power transmission path established includes power flow from at least a gear (260, 265) mounted on said first output shaft (215) or at least a gear (250, 255) mounted on said countershaft (210) connected via at least a synchro pack fork (218), when power flow from said input shaft gear (225) is coupled with at least a mating gear, at least said mating gear interconnected with at least a synchro pack (235), each said synchro pack (235) having at least a clutch body ring coupled to at least a sleeve (216), said at least sleeve (216) interconnected to at least a hub (212) splined to said first output shaft (215) or said countershaft (210) connecting with at least said gear (250, 255, 260, 265).

3. The transmission system as claimed in claim 1 or 2, wherein said power transmission path established includes power flow from at least a first and second final drive gears (270, 275) (FD) mounted on the countershaft (210) coupled to at least said synchro pack (235), each said synchro pack (235) having at least said hub (212) splined to said countershaft (210) or said second output shaft (220) coupled to at least said sleeve (216) engaged with at least said clutch body ring meshed to at least said mating gear splined to said second output shaft (220) for rotation of said second output shaft (220).

4. The transmission system as claimed in any one of the preceding claims 1-3, wherein at least said hub (212) has external and internal splines connecting said countershaft (210) and said first and second output shafts (215, 220), and at least said sleeves (216) has external and internal splines connecting at least said hub (212) and at least said gear (250, 255, 260, 265, 270, 275).

5. The transmission system as claimed in any one of the preceding claims 1-4, wherein at least said synchro pack (235) is mounted intermediate to at least said gears (250, 255, 260, 265, 270, 275), each said synchro pack (235) is actuated axially displacing from a normal position to an engaged position for engaging at least said gears (250, 255, 260, 265, 270, 275).

6. The transmission system as claimed in any one of the preceding claims 1-5, wherein said plurality of actuating solenoid valves includes a first solenoid valve connected to a 1st, 2nd synchro pack gear shifting fork (218), a second solenoid valve connected to a 3rd, 4th synchro pack gear shifting fork (218), a third solenoid valve connected to a first and second final drive (270, 275) synchro pack gear shifting fork (218) and a fourth solenoid valve connected to a reverse gear shifting fork (218).

7. The transmission system as claimed in any one of the preceding claims 1-6, wherein said 1st, 2nd, 3rd, and 4th synchro pack gear shifting forks (218) are operatively coupled to a gear lever for selectively shifting an input torque depending on the respective gear ratios of said plurality of driving and driven gears (250, 255, 260, 265) outputting the shifted torque through said first output shaft (215) to said countershaft (210) when said forks (218) engage splined hubs (212), gear sleeves (216) and synchro rings (214) of said gears (250, 255, 260, 265) in the axial direction establishing power transmission path displacing said driving and driven gears (250, 255, 260, 265) on respective first output shaft (215) and said countershaft (210) in combination with said first final drive (270) and second final drive (275) gears on said countershaft (210) to said second output shaft (220) in said forward multi-speed drive.

8. The transmission system as claimed in any one of the preceding claims 1-7, wherein said drive and driven gears (250, 255, 260, 265) for rotation include a first (265) and a second (260) drive gear coupled on said first output shaft (215) and a first (265) and a second (260) driven gear mounted on said countershaft (210) selectively meshed with said first final drive gear (270) or second final drive gear (275) mounted on the countershaft (210), said final drive gears (270, 275) coupled to said final driven gears (270, 275) mounted on the second output shaft (220) to output power in said forward multi-speed drive.

9. The transmission system as claimed in any one of the preceding claims 1-8, wherein said drive and driven gears for rotation include a third (255) and a fourth (250) driven gear coupled on said countershaft (210) selectively meshed with said first final drive gear (270) or second final drive gear (275) mounted on the countershaft (210), said final drive gears (270, 275) coupled to said final driven gears (270, 275) mounted on the second output shaft (220) to output power in said forward multi-speed drive.

10. The transmission system as claimed in any one of the preceding claims 1-9, wherein said first and second gears (265, 260) mounted on said first output shaft (215) are located to left side of an intermediate pate (240) and said third and fourth gears (255, 250) mounted on said second output shaft (220) are located to left side of the intermediate pate (240) at a first portion of said countershaft (210) and first final drive gear FD (270) and second final drive gear FD (275) are located on right side of said intermediated plate at a second portion of countershaft (210), and said reverse gear (280) mounted on second output shaft (220) on said right side of said intermediated plate at said second portion of countershaft (210).