DESC:FIELD OF INVENTION:
[001] The invention relates to transmission system used in vehicles and more particularly relates to the transmission with cross type gear engagement mechanism. The system may be applicable to manual or Automated Manual Transmission (AMT) system.
BACKGROUND OF INVENTION:
[002] Various types of gear shifting mechanisms are available out of which two types of gear shifting mechanism are well known first is drum type gear shifting mechanism where a drum and fork mechanism is used for shifting of gears and other is cross type mechanism or draw key type shifting mechanism wherein a shaft having a cross type gear engaging member is used to change or engage the different gears. The type of gear shift mechanism is decided based on available space, type of vehicle, gear ratios available and driving requirements etc.

[003] In drum type mechanism there are multiple gear ratios provided on multiple shafts with multiple forks or gear shifting members used to engage the gears. This increases the space. Also designing of drum and fork is complex and time consuming task as it requires machining and high accuracy. It is made using casting process which requires higher precision in manufacturing which increases cost. Whenever a gear shift is triggered either automatically or manually by driver of vehicle, the gear shift drum rotates by a predefined amount which is equivalent to required gear change. The rotation of shift drum causes the shifting of gears through usages of forks.

[004] The amount of force required in drum gear shift is more since in drum there is always a loss of force applied for gear shifting. This is due to the specific contour design present on the drum and low force transmission efficiency. Therefore in case of manual shift more force is required to shift a gear and hence it is generally operated by foot or by using a motor in drum type gear shifting.

[005] The other type of gear shifting mechanism is cross type mechanism or Draw key type shifting mechanism which comprises gear shifting shaft having a cross type member. During gear shifting a shaft engages cross member with desired gear pair. All the gear pairs are mounted linearly one after other on a single axis. Unlike drum shifting, in cross type mechanism only single gear engaging member is used instead of multiple forks which further helps in less complex arrangement. In the vehicles with cross type mechanism, hand operated gear shifting may be provided since the amount of force required for shifting the gears is comparatively less and gears can be changed easily.

[006] Considering the above facts it is advantageous to provide a cross type gear shifting mechanism rather than drum type mechanism in vehicles where the gears are operated by hand. Based on the recent development in the field of transmission most of the vehicles are shifting from manual transmission to automated manual transmission (AMT). In AMT systems the gear shifting is done using a motor or actuator instead of manually shifting the gears. There are AMT systems developed for drum type gear shifting mechanism in which a motor is used to rotate the drum which changes the gears. Applying this concept in case of drum is comparatively easy as the rotary motion of motor is applied to rotate the drum. However, when applying this concept in cross type mechanism there are different challenges as rotating gear actuation shaft has to be moved linearly and this linear movement needs to be precisely controlled to achieve the desired gear change. Any error in precisely controlling the linear movement of the gear actuation shaft may result in gear clash and other serious consequences. The major challenge is in designing the amount of linear movement required for the shaft for each gear change which in turn is in designing the amount of motor rotation required for each gear change and to precisely control and execute the linear movement of the gear actuation shaft.

[007] Another challenge is a space constraints as a limited space is available in a compact vehicle. Therefore, to package transmission system with or without AMT mechanism in available space is challenging. Also AMT system with motors shall not affect the existing design of other associated components/systems, location of the other associated components in vehicle. The vehicle layout need not be changed for shifting from manual transmission to AMT as there is a huge cost involved in having different vehicle layouts for different type of transmissions.

[008] It is an object of the present invention to provide Transmission system with cross type gear shift mechanism which can accurately shift the gears and another objective is to fit transmission system in existing vehicle without major modifications.
SUMMARY OF INVENTION:
[009] Transmission system for a vehicle comprising:
at least two gear pairs comprising first gear/s mounted on an shaft multiple gear in constant engagement with second gears mounted on a main shaft to form a said gear pair; at least one gear engaging member used to engage at least one gear pair; and an actuator connected to the gear engaging member wherein; the rotary motion of the actuator is converted into a linear motion of the gear engaging member using an intermediate linkage mechanism.

[010] The linkage mechanism for converting rotary motion of motor into linear motion of gear engaging member may be any suitable mechanism, preferably the linkage mechanism is a rack and pinion mechanism.

[011] The actuator may be an electric or mechanical drive source (for ex Manual gear shifting force) providing the required power to move the gear engaging member. The electric drive source may be an electric motor.

[012] The transmission system comprises at least two gear pairs arranged linearly one after another along a common axis. The first gear/s are mounted on the shaft multiple gears which receives power from engine. The first gear/s are in constant engagement with the corresponding second gears are loosely coupled on main shaft. Each second gear is having a corresponding provision in the form of at least one slot such as to accommodate the gear engaging member mounted on a gear actuation shaft. The gear engaging member is fitted on the gear actuation shaft which is moved linearly using the actuator using intermediate linkage mechanism, for ex rack and pinion mechanism.

[013] The gear engaging member is a cross type member with plurality lugs used for engaging the desired gear pair. The lugs provided on the gear engaging member inserts into corresponding slots provided on the inner diameter of second gear/s in order to engage any gear pair.

[014] The actuator is connected to gear actuation shaft through at least one gear reduction stage wherein, the output torque and speed of the actuator is controlled to a suitable torque and speed required for moving the gear actuation shaft. Preferably, the actuator output shaft is connected through at least two gear reduction stages. In first reduction stage the motor output shaft may be connected to clash relieving mechanism through first reduction gear pair and in second stage the clash relieving mechanism gear shaft is connected to a second shaft through another reduction gear pair forming second reduction stage.

[015] The clash relieving mechanism, construction and working is explained in applicant’s another patent application 3470/CHE/2011 dated 07/10/2011 the reference of which is brought herein. The clash relieving mechanism provides sufficient time to shift the gear in clash condition and helps in avoiding or overcoming the gear clash condition.

[016] The gear engaging member once engages any gear on the main shaft it starts rotating along with gears and therefore the gear actuation shaft also starts rotating. For changing the gears the actuation shaft which is in rotating condition needs to be moved in linear direction. To enable this, a shaft holder is provided to fit the gear actuation shaft inside the shaft holder such that it allows the gear actuation shaft to rotate while the gear actuation shaft may also move in linear direction. The shaft holder according to the present invention allows rotating shaft to move in a linear direction without affecting its rotational movement. The gear actuation shaft is fitted inside shaft holder through bearings. This allows the rotational movement of shaft w.r.t. shaft holder. The linkage mechanism, preferably in form of rack and pinion arrangement wherein the rack is provided on the outer body of the shaft holder which engages with pinion. When the pinion drive the rack in linear direction this also moves the gear actuation shaft in linear direction. Hence, the gear actuation shaft is having two movements one is rotational and other is linear or axial. As the gear engaging member is fixed on the gear actuation shaft, the gear engaging member is also having movements in two directions i.e. in rotational and linear.

[017] Once any gear pair is engaged it is necessary that the gear engaging member should be held in a position otherwise any axial movement may shift the position of gear engaging member and can result in disengagement or change of gear which may cause serious problems. The vibrations produced during vehicle operation may lead to such movement of gear engaging member. In order to prevent any movement, a holding mechanism is provided comprising a ball and spring mechanism along with undulations provided on outer surface of the gear actuation shaft. Ball and a spring mechanism is used along with undulation surface of gear actuation shaft to fix the position of gear actuation shaft which does not allow any linear movement of shaft and thereby of gear engaging member.

[018] The amount of linear movement of gear actuation shaft decides the gear pair to be engaged. Therefore a precise linear movement of gear actuation shaft is required. The linear movement of the actuation shaft is directly proportional to the rotational movement of second shaft as it drive the pinion and thereby rack. Hence, the precise control of rotational motion of second shaft is required. The angles corresponding to each gear are marked on the second shaft. The angle by which the second shaft rotates decides the amount of linear movement of gear actuation shaft and thereby decides which gear pair to be engaged. Therefore the two stage reduction gears are designed such that the second shaft does not rotate by complete 360 degrees. To have a better precision over linear movement of gear actuation shaft the gears in reduction stages are designed such that it allows maximum revolution of motor output shaft and minimizing the rotation angle of second shaft such that the second shaft never rotates more than 360 degrees for any gear change. Each angle of rotation of second shaft which corresponds to amount of linear movement of gear actuation shaft thereby corresponding to each gear pair. Therefore, the angles are designed such that all gears are shifted within a 360 degree rotation of the second shaft.

[019] As an embodiment of the present invention, the relative positions or angular movements of second shaft corresponding to each gear pair are marked and stored in a vehicle control unit (VCU) and is monitored through a gear position sensor (GPS). Whenever a gear needs to be changed to another gear pair, current gear position is sensed using the GPS and the motor output is controlled such that the second shaft is rotated through the pre-determined rotation angle required to engage the desired gear pair. As the second shaft rotates the gear actuation shaft moves linearly by the required distance through rack and pinion mechanism and engages the desired gear.

[020] AMT system also comprises a pre-stored data in a vehicle control unit (VCU) to give instruction to motor for changing gear. The pre-stored data comprises information about the gear pair to be engaged which is based on the various parameters including vehicle speed, load on vehicle, required torque, driving conditions etc. The vehicle parameters are monitored during vehicle running condition and provided to the controller of VCU. The controller compares the received data with pre-stored data and gives command to the motor for changing the gear pair.

[021] A clutch actuation motor may be provided separately for operating a clutch while changing the gear. Alternatively, same motor may be employed for changing gears as well as for operating clutch. During gear shift operation a clutch is disengaged and once desired gear is engaged it is detected by a sensor and the clutch is again engaged to deliver the power.

[022] A new transmission casing is developed such that the complete AMT mechanism is fitted on the transmission casing. According to preferred embodiment clutch actuation and gear shifting motors are fitted inclined on the transmission casing. This saves the vertical and axial height required for packaging motors and allows compact arrangement. The components of AMT system described above such as two stage reduction mechanism and rack and pinion mechanism are also fitted on or as a part of transmission casing preferably fitted on inner side of casing. This helps in achieving modularity. The manual transmission can be easily converted into AMT by just replacing an existing casing with new transmission casing and doing minor necessary modifications to make the system work. Rest the complete arrangement of other associated components such as gear arrangement, gear engaging member, gear actuation shaft, clutch etc. need not be changed or modified. Also an arrangement can be made in vehicle to change the mode of vehicle operation i.e. from manual to AMT wherein the motors may optionally get disengaged and the rest of the system operated with manual intervention.

[023] The complete AMT System described above is package in a vehicle without any interface to existing associated components. Also existing vehicle with manual transmission may be easily converted into AMT system using the described mechanism. The vehicle layout of all the components need not be different for vehicles with manual transmission and AMT. This helps in cost saving.

[024] The automated manual transmission system described herein above may be employed in any sort of cross type transmission system irrespective of number of gear pairs, type size or shape of gears, gear engaging member or gear actuation shaft. Also said system may be employed in any type of vehicle including two- wheeled, three-wheeled or four wheeled vehicle with any sort of prime mover including I.C. engine, electric motor or both.
BRIEF DESCRIPTION OF DRAWINGS
[025] The transmission system according to the present invention may be fully understood from the following description of preferred embodiments thereof, made with reference to accompanying drawings in which:

[026] Figure 1 is a side of conventional cross type transmission system according to prior art.

[027] Figure 2 is an orthogonal view of the transmission system according to a preferred embodiment of present invention.

[028] Figure 3 is a side view of the transmission system according to a preferred embodiment of present invention
[029] Figure 4 is a side view illustrating details of the transmission system according to a preferred embodiment of present invention.

[030] Figure 5 is an orthogonal view of transmission system illustrating gear arrangement according to a preferred embodiment of present invention.

[031] Figure 6 is a side view of the transmission system illustrating details of gear mounting and gar actuation shaft along with details related arrangement according to a preferred embodiment of present invention.

[032] Figure 7 is a side of gear actuation shaft used in the transmission system according to a preferred embodiment of present invention.

[033] Figure 8 is a side view illustrating details of holding mechanism used in the transmission system according to a preferred embodiment of present invention.

[034] Figure 9 illustrating details of position of a second shaft used in transmission system according to a preferred embodiment of present invention.

[035] Figure 10 is an orthogonal view of the transmission casing and packaging arrangement of the transmission system according to a preferred embodiment of present invention.

[036] Figure 11 is a sectional view illustrating the arrangement of transmission system inside transmission casing according to a preferred embodiment of present invention.

DETAIL DESCRIPTION OF INVENTION:
[037] During driving of a vehicle, based on the various driving conditions the speed and the torque requirement changes. As load on the vehicle increases the amount of torque required increases for example during stiff climbing the load on vehicle increases in such scenario the amount of output torque required increases. The required additional torque is generated by engaging lower gears which provides higher torque at lower speed. Similarly during low load scenario the requirement gets reversed and higher gears may be engaged which helps in increasing speed of vehicle. Hence during driving of vehicle based on load or driver’s requirement the gears are changed. In manual transmission the gears are changed manually by driver while in Automated Transmission System (AMT) gears are changed automatically based on different driving conditions.

[038] The system according to present invention is explained with the help of figure 1 to 11. Figure 1 shows an exemplary arrangement of a cross type gear shifting mechanism or draw key type shifting mechanism consisting of at least four second gears (110) mounted one after another on a main shaft (101). Each second gear/s (110) is engaged with first gear mounted on shaft multiple gear (not shown in fig.1) to form a gear pair. The first gear/s receives power from engine crankshaft (not shown). The second gears (110) is having a through bore (673) in which a cross type gear engaging member (552) is fitted on a gear actuation shaft (251). The gear engaging member (552) is provided with lugs which gets fitted inside the slots (525) provided in the second gear (110) thereby engaging the particular gear pair. The gear actuation shaft (251) and thereby the gear engaging member (552) can move linearly inside the bore (673) of the second gears (110). When a particular gear pair needs to be engaged the gear engaging member (552) is moved linearly by gear actuation shaft (251) and the lugs are engaged with the slots (525) provided on the desired gear pair. Conventionally said system is manually operated and has drawbacks cited above.

[039] The preferred embodiment according to present invention is hereinafter described with reference to fig. 2 to 11 which represents the arrangement of said transmission system (100).

[040] A motor (200) for shifting gears is connected to the gear actuation shaft (251) through a linkage mechanism preferable provided with rack and pinion arrangement (403). The motor output shaft (211) is preferably connected to the gear actuation shaft (251) through two stage reduction arrangement (600) and a rack and pinion mechanism (403). The output shaft of motor (211) may be connected to a clash relieving mechanism (402) through a first reduction gear (205) which also acts to minimize the possibility of occurring gear clash condition. The clash relieving mechanism (402) is further connected to a second shaft (400) through a second reduction gear pair (410). The first and second reduction gear pairs modify the motor output torque suitably to achieve the gear shifting. The number of reduction gear pairs may change based on the required output torque, capacity of motor etc. or motor (200) may be directly connected to the second shaft (400). Therefore as the motor output shaft (211) rotates the second shaft (400) also rotates but with different speed and torque. The clash relieving mechanism, construction and working is explained in applicant’s another patent application 3470/CHE/2011 dated 07/10/2011 the reference of which is brought herein. The clash relieving mechanism provides sufficient time to shift the gear in clash condition.

[041] The rack and pinion mechanism (403) wherein, a pinion (401) is provided on the second shaft (400) and rotates along with the second shaft (400). The pinion (401) engages with a rack (301). Rotary motion of pinion (401) is converted into linear motion of the rack (301) which is further utilized to move the gear actuation shaft (251) in linear direction. The rack and pinion mechanism (403) moves the gear actuation shaft (251) in linear direction. The gear actuation shaft (251) is provided inside a shaft holder (311) wherein, the shaft holder (311) is provided with said rack (301) on its outer surface.

[042] Therefore, during operation as the motor output shaft (211) rotates, the second shaft also rotates which in turn rotates the pinion (401). The rotational motion of pinion (401) is converted to linear motion of rack (301) which moves the gear actuation shaft (251) in linear direction backward or forward. As the gear actuation shaft (251) is moved, the gear engaging member (552) is also moves and gets engaged with the required gear pair since the gear engaging member (552) is fixed on the gear actuation shaft (251) such that the shaft (251) may be moved in a linear direction along with the gear engaging member (552).

[043] Fig. 5 and 6 illustrates the mounting of second gears (110) on the main shaft (101). The gears (110) four in number with different gear ratios are arranged in linear direction along a common axis on the main shaft (101). The corresponding first gears are arranged on the shaft multiple gear linearly in a similar way (not shown). The gears are in constant engagement to form a gear pair. The number of gear pairs may vary based on the requirement of vehicle and amount of output torque or speed required for vehicle as explained above.

[044] The cross type gear shifting mechanism is moveably fixed within the bore of second gears (110). The gear actuation shaft (251) can slide through inside the bore (673) of second gears (110) along with the gear engaging member (552). The gear engaging member (552) is a cross type circular member having plurality of lugs (552a) which engages with corresponding at least one slot (525) provided on each second gear/s (110) which results in the engagement of gear pair. As the gear engaging member (552) moves from one position to another the lugs (552a) provided on gear engaging member (552) gets engaged with at least one slot (525) provided on the desired second gear (110) which results in shifting of gear.

[045] Once the gear engaging member (552) engages with any of the second gear 110, the gear pair gets engaged and the gear actuation shaft (251) along with gear engaging member (552) starts rotating.

[046] The gear actuation shaft (251) has a rotational motion and cannot be directly given a linear motion as the shaft is rotating. Hence the rack and pinion mechanism (403) cannot be directly provided on the actuation shaft (251). Therefore the gear actuation shaft (251) is mounted inside the shaft holder (311) which allows the shaft (251) to rotate as well as move the shaft in linear direction. The shaft holder (311) is tubular member having at least one end open. The gear actuation shaft (251) is fitted inside the tubular type shaft holder (311) using bearings (335) which allows the shaft to rotate inside the shaft holder (311). The rack (301) is provided on the outer body of the shaft holder (311) which engages with the pinion (401) provided on the second shaft (400) as described above. As the pinion (401) rotates it moves the rack (301) i.e. shaft holder (311) in linear direction. The shaft holder (311) forces the rotating gear actuation shaft (251) to move in same direction while still allowing rotational movement of gear actuation shaft. Therefore, the cross type mechanism is provided with motion in two directions i.e. linear and rotational.

[047] Once a particular gear pair is engaged then the gear engaging member (552) must remain engaged until it is shifted to next gear pair. Therefore, the position of gear engaging member (552) needs to be secured in the engaged position. To achieve this the system is provided with a holding mechanism (625) which is used to maintain the position of gear engaging member (552) and comprises a ball (615) and a spring (635) and the gear actuation shaft (251) is provided with undulations (650) on its outer surface. These undulations along with ball (615) and spring (635) mechanism helps in maintaining the position of the gear engaging member (552).

[048] The lower crest (651) of undulations (650) forms a seat for a ball (615). Once the gear is engaged in a particular position the ball (615) comes in the lower crest (651) and locks the position of the shaft in current position with the help of spring force (635) which is mounted on top of ball (615). When there is a gear change requirement, the gear actuation shaft (251) moves in linear direction. The upward undulations (652) of the shaft forces the ball (615) to move upward and the spring (635) gets compressed. Once the next gear is engaged again the ball (615) comes again in lower crest (651) of the undulation and secures the gear actuation shaft (251) in that position. The undulations (650) also helps in smooth changing of gears with lesser force and also provides a haptic feedback to the driver of vehicle when the gear is changed. Therefore, the undulations (650) of gear actuation shaft (251) are designed such that when a gear is engaged the ball (615) comes in the lower crest (651) and locks any movement of gear actuation shaft (251) in either direction. Though ball (615) and spring (635) are used as a preferred embodiment any other suitable means may be utilized to maintain the position of gear actuation shaft (251).

[049] Fig. 9 and table 1 below represents various angular movements for second shaft (400) required for shifting the gear (110) as per one of the embodiment of present invention. The amount by which the gear actuation shaft (251) is moved linearly decides the gear pair to be engaged. Therefore a precise linear movement of gear actuation shaft (251) is required. The rotational movement of second shaft (400) is directly proportional to the linear movement of the actuation shaft (251) as it drives the pinion (401) and thereby rack (301). Hence, the precise control of rotational motion of second shaft (400) is required. The second shaft (400) does not rotate by complete 360 degrees since each angle of rotation is marked corresponding to particular gear pair. The angle by which the second shaft (400) rotates decides the amount of linear movement of gear actuation shaft (251) and thereby decides which gear pair to be engaged. For example, to shift the gear from 1st gear pair to neutral the gear engaging member (552) has to be moved by 7.5mm in axial direction. To achieve this the pinion (401) of second shaft (400) has to be moved by 14.8 degrees which forces the rack (301) to move by the 7.5mm which moves the gear actuation shaft (251) and thereby the gear engaging member (552) by required 7.5mm distance. Therefore for each gear shifting the required axial distance to be travelled for the gear engaging member (552) and the corresponding angle of rotation for second shaft (400) is calculated and stored in the control unit of vehicle (VCU). When a particular gear shift is required the distance to be travelled by gear engaging member (552) and the angle of rotation required for second shaft (400) or pinion (401) is determined from the pre-stored data and accordingly motor (200) is operated to move the rack (301). This helps in achieving the required gear shift. The current gear position and achieved gear position is sensed by a gear position sensor (not shown). The table below represents values of axial movement for gear engaging member (552) corresponding to each gear change and also values of related angle of rotation of second shaft (400) corresponding to respective gear pairs are given according to one of the embodiment of present invention. The total angle of rotation of second shaft (400) is 311 degrees which is less than 360.
Gear Shift Axial travel (mm) Rotational Angle of second shaft (degrees)
1st to N 7.5 56.5°
N to 2nd 7.6 57.3°
2nd to 3rd 13 98.0°
3rd to 4th 13.1 98.8°
Total Angle Travel 311°

[050] The two stage reduction mechanism (600) is designed such that the gear shift motor (200) is allowed to rotate with maximum rotations during gear shift while the second shaft (400) is allowed to slowly rotate such that any required gear shift is completed before the second shaft (400) is rotated by complete 360°. The maximum rotation of motor output shaft (211) allows more precise control of the linear movement of gear actuation shaft (251) and provides better control.

[051] The data is stored in the vehicle control unit (VCU) to give instruction to motor (200) for changing gear. The pre-stored data comprises information about the gear pair to be engaged which is based on the various parameters including vehicle speed, load on vehicle, required torque, driving conditions etc. The vehicle parameters are monitored using various sensors during vehicle running condition and provided to the controller (not shown). The controller compares the received data with pre-stored data and gives command to the motor (200) for changing the gear pair.

[052] The transmission system (100) also comprises a motor (201) for operating a clutch. A motor (200) used for gear shifting may also be utilized for operating clutch or alternately a dedicated motor for clutch operation is provided.

[053] According to an embodiment of present invention the transmission system (100) is compactly mounted on a transmission casing (951) such that the system (100) has minimum interference with other components of vehicle and requires minimum modifications in the existing vehicle design as shown in figure 10 and 11. The transmission casing (951) is fitted with two motors i.e. a gear shifting motor (200) and a clutch actuation motor (201). Both motors are preferably fitted inclined at an acute angle or obtuse angle which helps in occupying minimum space in vertical direction though horizontal, straight or inclination at any angle is possible for fitting the motors which is preferably decided based on available space in vehicle. The transmission casing (951) may be a clutch cover or a crankcase cover.

[054] The output shaft of motor (211) is inside transmission casing (951) and engaged with two stage reduction mechanism (600) as explained above. All the other associated components of transmission system (100) such as rack and pinion mechanism (403), two stage reduction mechanism (600) etc. are fitted inside the casing (951). Alternately, the associated components such as reduction mechanism (600), rack and pinion mechanism (403) etc. may also be fitted outside the casing (951) either partially or completely. The rest of the transmission arrangement remains identical for manual transmission and automated transmission like number of gear pairs, cross type gear engaging member etc. This helps in modularity and the existing manual transmission can also be converted into automated manual transmission by changing a transmission casing having said arrangement.

[055] According to one of the embodiment of present invention the vehicle may be provided with both manual and AMT system. An arrangement can be made in vehicle wherein the vehicle driver or operator may shift the transmission from manual to automatic. The mode of vehicle operation may be changed i.e. from AMT to manual and vice-versa. The motors (200,201) may be optionally engaged or disengaged based on selected mode. While shifting from AMT to manual the motor (200, 201) and its two stage reduction mechanism (600) gets optionally disengaged and gear engaging member (552) operates with manual intervention. Manual intervention may be in the form of hand operated or switch operated gear or clutch.

[056] Modifications and variations to the AMT system described in the present specification may be apparent to skilled readers of this disclosure. Such modifications and variations are deemed within the scope of the present invention.
,CLAIMS:
1. Transmission system (100) for a vehicle comprising:
at least two gear pairs comprising first gear/s mounted on a shaft multiple gear in constant engagement with second gears (110) mounted on an main shaft (101) to form a said gear pair,
at least one gear engaging member (552) used to engage at least one gear pair; and
an actuator (200) connected to the gear engaging member (552) wherein; the rotary motion of the actuator (200) is converted into a linear motion of the gear engaging member (552) using an intermediate linkage mechanism (403).

2. Transmission system (100) for a vehicle as claimed in claim 1 wherein; the linkage mechanism (403) for converting rotary motion of the actuator (200) into linear motion of gear engaging member (552) is a rack and pinion mechanism (403).

3. Transmission system (100) for a vehicle as claimed in claim 1 wherein; the actuator (200) is an electric actuator including an electric motor or a mechanical drive source providing the required power to actuate the gear engaging member (552).

4. The transmission system (100) as claimed in claim 1 wherein; each second gear/s (110) on the main shaft (101) is having a corresponding provision (673) to accommodate said gear engaging member (552).

5. The transmission system (100) as claimed in claim 4 wherein; the gear engaging member (552) is mounted on a gear actuation shaft (251) and is a cross type member with plurality lugs (552a) used for engaging the desired gear pair by inserting the lugs (552a) provided on the gear engaging member (552) into corresponding accommodating provision in form of slot (525) provided on the inner diameter of the second gear/s (110).

6. The transmission system (100) as claimed in claim 5 wherein; the gear actuation shaft (251) is in connection with the actuator (200) through at least one gear reduction stage (600) used to control the output torque and speed of the actuator (200) to a required torque and speed suitable for actuating the gear actuation shaft (251).

7. The transmission system (100) as claimed in claim 6 wherein; the gear actuation shaft (251) is in connection with the actuator (200) through at least two gear reduction stages (600) wherein; in first reduction stage the actuator output shaft (211) is connected to clash relieving mechanism (402) through first reduction gear pair (205) and in second stage the clash relieving mechanism gear shaft (402) is connected to a second shaft (400) through another reduction gear pair (410) forming second reduction stage.

8. The transmission system (100) as claimed in claim 6 or 7 wherein; the gears in reduction stages (205, 410) are designed to allows maximum revolution of actuator output shaft (211) which causes minimum rotation of the second shaft (400) such that the second shaft (400) never rotates more than 360 degrees for any gear change.

9. The transmission system (100) as claimed in claim 6 or 7 wherein; the gear actuation shaft (251) is fitted inside a shaft holder (311) through bearing (335) such that the shaft holder (311) is configured to move the gear actuation shaft (251) in a linear direction using the power received by the actuator (200) through gear reduction stage/s (205,410).

10. The transmission system (100) as claimed in claim 9 wherein; the shaft holder (311) is provided with rack type configuration (301) on the outer surface and is in connection with a pinion (401) mounted on the second shaft (400) such that the rotational motion of the pinion (401) is converted into linear motion of the shaft holder (311) and thereby moving the gear actuation shaft (251) in a linear direction.

11. The transmission system (100) as claimed in claim 6 or 7 wherein; the gear actuation shaft (251) is fixed in position once any gear pair is engaged using a holding mechanism (625) comprising a ball and a spring (615, 635) such that the ball (615) gets fitted within undulation (650) provided on outer surface of the gear actuation shaft (251).

12. The transmission system (100) as claimed in claim 6 or 7 wherein; the gear pair is engaged and disengaged by operating a clutch using a clutch actuator (201).

13. The transmission system (100) as claimed in claim 12 wherein; the clutch actuator (201) and the actuator (200) for gear engagement are mounted on a casing (951) such that both the actuators (200, 201) are mounted inclined wherein; said casing (951) is a transmission casing or a clutch cover or a crankcase cover.

14. The transmission system (100) as claimed in claim 13 wherein; the gear reduction stage (205, 410) including intermediate linkage mechanism (403) is at least partially fitted inside said casing (951).

15. The transmission system (100) as claimed in claim 7 wherein; the angular movements of second shaft (400) corresponds to engagement of the gear pair are marked and stored in a vehicle control unit (VCU) wherein; the vehicle control unit (VCU) is configured to control the actuator (200) such that the second shaft (400) is rotated through the pre-determined rotation angle required to engage the desired gear pair by moving the gear actuation shaft (251) in a linear direction.

16. The transmission system (100) as claimed in claim 15 wherein; the vehicle control unit (VCU) is in connection with a gear position sensor (GPS) to sense current gear position.

17. The transmission system (100) as claimed in claim 15 wherein; the vehicle control unit (VCU) is configured to change the gear pair based at least one parameters including vehicle speed, load on vehicle, required torque, driving conditions wherein said parameters are monitored during vehicle running condition and communicated to the VCU for comparing with a pre-stored data to give command to the actuator (200) for changing/ engaging any desired gear pair based on said comparison.

18. The transmission system (100) as claimed in claim 3 wherein; the actuator (200) is optionally disengaged and the rest of the system is operated with manual intervention to change the mode of vehicle operation from AMT to manual.

19. The transmission system (100) as claimed in claim 1 is employed in any sort transmission system irrespective of type, size or shape of gear engaging member (552) or number of gear pairs and deployed in any type of vehicle including two- wheeled, three-wheeled or four wheeled vehicle with any sort of prime mover including I.C. engine, electric motor or both.