FIELD OF INVENTION:
[001] The present subject matter described herein, relates to manual transmission system for gear shifting, and, in particular, to a noise free shifting of reverse gear in manual transmission.
BACKGROUND AND PRIOR ART:
[002] Generally, in manual transmissions, vehicle operator moves stick which is connected to a gear shift lever to change gears in gearbox via gear shift mechanism. The gearbox comprises an input shaft and an output shaft which are interlinked with each other. The input shaft has plurality of forward gear sets which engaged with gears of output shaft to drive the vehicle. Further, the gearbox has a reverse idler assembly for engaging the vehicle in reverse gear. Generally, the reverse idler assembly has a reverse input gear driven by the input shaft, a reverse output gear driven by the output shaft, and a reverse idler gear which is selectively movable into meshed engagement with the reverse input gear and the reverse output gear for driving the output shaft in a second direction. The reverse idler gear is a gear used to change the direction of the rotation of the shafts.
[003] During operation of the vehicle, when operator shifts the reverse gear, the input shaft got disengages from the output shaft and rotates freely due to inertia. In this situation, if the vehicle operator moves the gear (stick) in reverse gear position to shift the reverse gear mode while the input shaft is still rotating, teeth of the reverse gear idler meshes with the teeth of the reverse input gear and reverse idler gear starts rotating. Wherein teeth of the rotating reverse gear idler get clashed with the teeth of the rotating output shaft and create clattering noise. This condition is generally known as “reverse clash” which results in unpleasant noise and clashing/vibrations are felt by vehicle operator. Sometime, the vehicle operator is unsuccessful to put the vehicle in the reverse gear. Therefore, overall reverse gear shifting is difficult and brings more wear and tear in the gearbox.
[004] In order to avoid this situation, the vehicle operator has to wait till the time when input shaft stop rotating. This consumes lot of time and irritates the vehicle operator. Further, there is another way to avoid this reverse clashing is to stop the rotation of the input shaft before an attempt is to made to put the vehicle in reverse gear. There are several techniques which removes the reverse clash in the gear box.
[005] Figure 1 & 2 shows existing system for solution of the above mentioned problem. As shown, the system has a sleeve 1, hub 2, lever 3, synchronizer ring 4, and gear (fifth gear) 5 to stop the rotation of the input shaft. When the operator moves the gear Lever in reverse gear direction, the sleeve is moved away from the gear by the gear shift lever. The movement of the sleeve causes the ring and lever to stop the movement of the rotating shaft. While engaging the reverse gear, sleeve moves the lever 3 and pushes the synchronizer ring 4 against a fulcrum point 6 on the hub 2 towards the fifth gear (stationary) and thus Brakes the rotating Input shaft leading to reverse gear clashing noise prevention. Further, this system uses the fifth gear to stop the rotation of the input shaft.
[006] US Patent 5845531 relates to a reverse brake incorporated into the gear train of a manual transmission which functions to stop inertial rotation of the input shaft prior to engagement of reverse gear. In particular, a constant-mesh gear set is operable with a first clutch to establish a forward drive connection between the input shaft and the output shaft, and is further operable with a second clutch to brake rotation of the input shaft without establishing a forward drive connection with the output shaft.
[007] US Patent US5802917 discloses a gear shifting mechanism and method are provided for change-speed gearboxes of motor vehicles with braking of an input shaft of the gearbox during engagement of reverse gear. The gearbox includes a gearbox housing, a shifter shaft radially pivotably, and axially slidably supported by the housing. A plurality of shifter forks are supported by the shifter shaft. A reverse fork includes an arm having a groove. A shifter rod is supported by the housing adjacent the shifter shaft. A shifter finger is supported by the shifter rod. The finger is engageable in the groove of the arm to selectively move the reverse fork. A shift interlock is substantially axially fixed to the housing. The interlock includes a blocking plate rotatable with the shift finger to selectively block movement of a shifter fork. An interlock connector releasably connects the shift interlock for axial movement with the shifter finger or the shifter shaft to axially move the forward shifter fork during engagement of reverse gear.
[008] Though these prior arts reduces the reverse clash as they are intended for, but each has its own drawbacks and limitations. These known systems are costly and have several special parts which are very complex. This complexity makes the serviceability of the system difficult and costly. Further, these systems increase the reverse gear blockage which ultimately becomes uncomfortable for reverse gear shifting. Therefore, a simple and inexpensive reverse gear shifting system is required which is effective to eliminate reverse gear clash while shifting the gear shift lever from forward gear to reverse gear.
OBJECTS OF THE INVENTION:
[009] The principal objective of the present invention is to provide reverse clash free gear shifting of reverse gear in vehicle.
[0010] Another object of the present subject matter is to use second gear synchronizer ring for stopping the rotation of input shaft.
[0011] Another object of the present invention is to use lever mounted on shift tower shaft to slow down rotation of input shaft.
[0012] Another object of the present invention is to provide simple structure to eliminate reverse clash in the gearbox.
[0013] Yet another object of the present invention is to provide low cost system for reduction of noise in the gearbox while reverse gearing.
SUMMARY OF THE INVENTION:
[0014] The subject matter disclosed herein relates to a manual transmission system for applying brakes on rotating input shaft of gearbox during shifting of reverse gear. The manual transmission system comprises a shift tower shaft and a gear shift lever which is mounted on the shift tower shaft to select gears, such as first, second, third, fourth, fifth, and reverse gear. The manual transmission system further comprises a lever which is mounted co-axially on the shift tower shaft below the gear shift lever to push second gear synchronizer ring to apply Brake on the rotating input shaft. A yoke is mounted on first and second gear shift rail of a plurality of gear shift rails and has a rectangular slot. The lever engages with the rectangular slot of the yoke when reverse gear selection is made and pushes the yoke in a direction to partially engage the second gear. The yoke pushes a fork mounted on the first and second gear shift rail to push second gear synchronizer sleeve which further pushes the second gear synchronizer ring to get partially engage with the rotating input shaft and apply Brake on the rotating input shaft.
[0015] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0017] Fig. 1 illustrates lever synchronizer system for applying Brake on fifth gear to stop the rotating input shaft as known in the art;
[0018] Fig. 2 illustrates working of the lever synchronizer system for applying Brake on fifth gear to stop the rotating input shaft as known in the art;
[0019] Fig. 3A illustrates arrangement of gear shift rails and gear shift lever in the gear box along with lever which is mounted on shift tower shaft, in accordance with an embodiment of the present subject member;
[0020] Fig. 3B illustrates enlarged view of the gear shift lever and lever mounted on the shift tower shaft and disengagement of lever with the yoke, in accordance with an embodiment of the present subject matter;
[0021] Fig. 4A illustrates gearbox having fork, gear shift rails, lever and shift tower shaft for the present system, in accordance with an embodiment of the present subject matter;
[0022] Fig. 4B illustrates engagement of lever with the slot on yoke and movement of yoke mounted on second gear shift rail to apply Brake on the rotating input shaft, in accordance with an embodiment of the present subject matter;
[0023] Fig. 5 illustrates movement of second gear synchronizer ring towards the rotating shaft and applying Brake on the input shaft, in accordance with an embodiment of the present subject matter; and
[0024] Fig. 6 depicts the second version of lever in which spring and lever has been replaced by a lever attached to shaft with the ratchet pawl arrangement inside at shift tower, in accordance with an embodiment of the present subject matter. The ratchet pawl arrangement bring back the lever back to its original position once it comes out of the slot.
[0025] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0026] The subject matter disclosed herein relates to manual transmission of gear shifting in gearbox of vehicle. The gearbox has a lever mounted on the shift tower shaft below gear shift lever. Further, a slot is cut on a yoke mounted on second gear shift rail to receive the lever. When the vehicle operator tries to shift the reverse gear, the forward gear is disengaged with the output shaft and input shaft is freely rotating. While selecting the reverse gear, the lever mounted on the shift tower shaft engages with the slot built in the yoke of the second gear shift rail. While the vehicle operator applies the force to shift the reverse gear, the lever mounted on the shift tower shaft get actuated and pushes the second gear synchronizer ring against second gear (counter shaft) which is connected with the rotating input shaft. After pushing the second gear shift rail, the second gear synchronizer ring get partially engaged with the second gear (counter shaft) which is connected with the rotating input shaft and applies Brake on the rotating input shaft. The second gear synchronizer ring got disengaged from the rotating input shaft when the lever comes out from the slot of the yoke mounted on the second gear shift rail. Further, the continuous force from the vehicle operator shifts the reverse gear in the gearbox. The lever pushes the second gear synchronizer ring to apply Brake on the rotating input shaft. The lever comes back to its original place due to spring action and while returning to neutral position and hits the slot on the yoke to bring back the 2nd gear shaft to neutral position. Conventionally, when operator selects the reverse gear, the input shaft got disengages from the output shaft and rotates freely due to inertia. In this situation, if the vehicle operator moves the gear Lever in reverse gear position to put the vehicle in reverse gear mode while the input shaft is still rotating, teeth of the reverse gear idler will strike with the teeth of reverse input gear. When the vehicle operator applies force to put the vehicle in reverse gear mode and the reverse gear tries to engage with rotating input shaft. Wherein teeth of the reverse gear idler got clashed with the teeth of the rotating input shaft and create clattering noise. This condition is generally known as “reverse clash” which results in unpleasant noise and clashing/vibrations are felt by vehicle operator. Sometime, the vehicle operator is unsuccessful to put the vehicle in the reverse gear. Therefore, overall reverse gear shifting is difficult and brings more wear and tear in the gearbox. .
[0027] According to present subject matter, a lever is provided under the gear shift lever which is mounted on shift tower shaft. Further, a slot is cut on a yoke mounted on the second gear shift rail to receive the lever while selecting the reverse gear. When the vehicle operator tries to select the reverse gear, the forward gear is disengaged with the output shaft and input shaft is freely rotating on its axis. While selecting the reverse gear, the lever coaxially mounted on the shift tower shaft get engage with the slot built on the yoke of the second gear shift rail. As the vehicle operator applies the force to select the reverse gear, the lever mounted on the shift tower shaft get actuated and pushes the second gear synchronizer ring which is connected with second gear shift rail to get engage with the rotating input shaft. After pushing the second gear shift rail, the second gear synchronizer ring got partially engaged with the rotating input shaft and, accordingly, applies Brake on the rotating input shaft. The second gear synchronizer ring got disengaged from the rotating input shaft when the lever comes out from the slot present on the yoke of the second gear shift rail. Further, the continuous force from the vehicle operator selects the reverse gear in the gearbox. The lever pushes the second gear synchronizer ring to apply Brake on the rotating input shaft. The lever comes back to its original place due to spring action and while returning to neutral position and hits the slot on the yoke to bring back the 2nd gear shaft to neutral position.
[0028] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0029] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0030] Fig. 3A illustrates arrangement of gear shift rails and gear shift lever in the gear box along with lever mounted on shift tower shaft in the gearbox, in accordance with an embodiment of the present subject member. The gearbox 30 includes shift tower shaft 31, a plurality of gear shift rails 32, 33, 34, input shaft 35, output shaft 36, gear shift lever 38, and lever 39. Further, the gear box 30 includes a plurality of forks 37. The shift tower shaft 31 is connected with gear Lever via gear shift linkage to receive shifting of gear by the vehicle operator. On the shift tower shaft 31, a gear shift lever 38 is mounted to activate the gear shifting in the gearbox. The plurality of gear shift rails 32, 33, 34 is a set of shafts that are connected to the plurality of forks 37 in the gear box 30. The plurality of forks 37 (individually may be referred as fork 37) are parts that move on the shifting of gear and actually moves the component to change the gears inside the gearbox 30. For example, for five speed transmission, there are three gear shift rails. The vehicle operator moves the one gear shift rail forward and backward to select the two possibilities of the gear. For example, first shift rail 34 is moved forward and backward to select first and second gear. Similarly, second shift rail 33 is moved to select third and fourth gear, and third shift rail 32 is moved to select fifth and reverse gear. Further, a synchronizer sleeve is connected with fork 37. The synchronizer sleeve receives the input from the fork 37 and moves forward and backward as per input to shift the gear. A lever 39 is coaxially mounted below the gear shift lever 38 which activates only when the vehicle operator shifts the reverse gear.
[0031] Fig. 3B illustrates enlarged view of the gear shift lever and lever co-axially mounted on shift tower shaft, in accordance with an embodiment of the present subject matter. Further, the Fig. 3B illustrate the disengage view of the lever with the slot when reverse gear is not selected. The lever 39 co-axially mounted on the shift tower shaft 31 below the gear shift lever 38 which shifts the gear as per input. On the first and second gear shift rail 34, a yoke 40 is mounted. The yoke 40 surrounds the first and second gear shift rail 34 and has rectangular slot 41 facing the shift tower shaft 31. Further, the slot 41 is to receive the lever 39 while selecting the reverse gear. When the vehicle operator tries to select the reverse gear, the forward gear is disengaged with the output shaft and input shaft is freely rotating on its axis.
[0032] Fig. 4A illustrates gearbox having fork, gear shift rails, lever and shift tower shaft for the present system, in accordance with an embodiment of the present subject matter. The gearbox 30 has a plurality of forks mounted on the plurality of gear shift rails. During shifting of the gears, the plurality of forks 37 pushes the corresponding gear synchronizer sleeves which are connected with forks. Further, selected gear synchronizer sleeve pushes corresponding gear synchronizer ring to get engage with corresponding gear of the input shaft or counter shaft.
[0033] Further, the gear shift rails are arranged in bottom to top order. Gear shift rail of first and second gear 34 is at bottom, then gear shift rail of third and fourth gear 33 is present at middle and at the top gear shift rail of fifth and reverse gear 32 is present at top.
[0034] Fig. 4B illustrates movement of yoke mounted on first and second gear shift rail to apply brake on the rotating input shaft, in accordance with an embodiment of the present subject matter. Further, Fig. 4b shows the engagement of lever 39 with the slot 41 and movement of yoke 40 with the lever 39. The lever 39 is mounted below the gear shift lever 38. The lever 39 engages with the slot 41 of the first and second gear shift rail 34 when the reverse gear is selected which is at the top. For example, the shift tower shaft moves toward left hand side to push the fifth and reverse gear shift rail towards left hand side to shift the reverse gear. As the shift tower shaft moves to shift the reverse gear, the lever 39 get engage with the slot 41 of the yoke 40 and slightly pushes the fork and sleeve and 2nd gear synchronizer ring to apply Brake on the rotating input shaft.
[0035] While shifting the reverse gear, the lever 39 mounted on the shift tower shaft 31 get engage with the slot 41 present on the yoke 40 of the first and second gear shift rail 34. As the vehicle operator applies the force to shift the reverse gear, the lever 39 coaxially mounted on the shift tower shaft 31 moved along with the movement of the shift tower shaft 31. The lever 39 get engaged with the slot 41 and pushes the yoke 40 in direction ‘Q’ (as shown in Figure 4B). The direction of the yoke is to engage second gear with the rotating input shaft 35. Further, the yoke 40 pushes the fork 37 which is mounted on the first and second gear shift rail 34. The fork 37 further pushes the second gear synchronizer sleeve 50 which is connected with fork 37. The second gear synchronizer sleeve 50 pushes second gear synchronizer ring 51 to get engage with counter shaft 2nd gear which is connected with the rotating input shaft 35 to apply the brake on input shaft by partially engaging the 2nd gear.
[0036] Fig. 5 illustrates movement of stationary second gear synchronizer ring towards the rotating 2nd gear counter shaft and applying Brake on the input shaft, in accordance with an embodiment of the present subject matter. The second gear synchronizer ring 51 brakes the rotating second gear counter shaft 52 which is connected with 2nd gear input shaft 53 hence braking the rotating input shaft.
[0037] After giving a calculated stroke to yoke 40, the lever 39 disengages from the slot 41 present on the yoke 40 of the first and second gear shift rail 34. Further, the lever 39 has a spring 39-A which helps the lever 39 to regain its original position while shifting from reverse to neutral. The present system for applying break on the rotating input shaft through second synchronizer ring is very simple and cost effective.
[0038] Fig. 6 depicts the second version of lever in which spring and lever has been replaced by a lever attached to shaft 31 with the ratchet pawl arrangement inside at shift tower. The ratchet pawl arrangement bring back the lever back to its original position once it comes out of the slot.
[0039] A manual transmission system for applying brake on rotating input shaft (35) of gearbox (30) during shifting of reverse gear, the manual transmission comprises:a shift tower shaft (31); a gear shift lever (38) is mounted on the shift tower shaft (31) to shift gears; and a lever (39) is mounted co-axially on the shift tower shaft (31) below the gear shift lever (38) to push second gear synchronizer ring (51) to apply brake on the rotating input shaft (35). The gearbox (30) has the input shaft (35) and an output shaft (36) which is connected with the input shaft (35) to be driven in a direction.
[0040] Further the gearbox (30) has a plurality of gear shift rails (32, 33, 34) and a plurality of forks (37). The plurality of forks (37) is connected with the plurality of gear shift rails (32, 33, 34) to change gears in the gear box (30). A yoke (40) is mounted on first and second gear shift rail (34) of the plurality of gear shift rails (32, 33, 34) and has a rectangular slot (41) over its surface. The lever (39) engages with the rectangular slot (41) of the yoke (40) when reverse gear selection is made and pushes the yoke (40) in a direction to engage second gear.
[0041] The manual transmission system as claimed in claim 1 or 6, wherein the second gear synchronizer sleeve (50) pushes the second gear synchronizer ring (51) to get partially engage with the rotating counter shaft 2nd gear which is connected with 2nd gear input shaft and apply break on the rotating input shaft (35). the lever (39) engages with the rectangular slot (41) of the yoke (40) when reverse gear selection is made and pushes the yoke (40) in a direction to engage second gear. the lever (39) has spring to regain its original position after disengagement from the rectangular slot (41) when shifting from reverse to neutral. the plurality of gear shift rails (32, 33, 34) are arranged in bottom to top order, wherein at bottom the first and second gear shift rail (34), at middle third and fourth gear shift rail (33), and at top fifth and reverse gear shift rail (32) is present
[0042] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/device of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

We claim:
1. A manual transmission system for applying brakes on rotating input shaft (35) of gearbox (30) during shifting of reverse gear, the manual transmission comprises:
a shift tower shaft (31);
a gear shift lever (38) is mounted on the shift tower shaft (31) to shift gears; and
a lever (39) is mounted co-axially on the shift tower shaft (31) below the gear shift lever (38) to push second gear synchronizer ring (51) to apply brake on the rotating input shaft (35).

2. The manual transmission system as claimed in claim 1, wherein the gearbox (30) comprises:
the input shaft (35); and
an output shaft (36) which is connected with the input shaft (35) to be driven in a direction.

3. The manual transmission system as claimed in claim 1, wherein the gearbox (30) comprises:
a plurality of gear shift rails (32, 33, 34); and
a plurality of forks (37), wherein the plurality of forks (37) are connected with the plurality of gear shift rails (32, 33, 34) to change gears in the gear box (30).

4. The manual transmission system as claimed in claim 1, wherein a yoke (40) is mounted on first and second gear shift rail (34) of the plurality of gear shift rails (32, 33, 34) and has a rectangular slot (41) over its surface.

5. The manual transmission system as claimed in claim 1, wherein the lever (39) engages with the rectangular slot (41) of the yoke (40) when reverse gear selection is made and pushes the yoke (40) in a direction to engage second gear.
6. The manual transmission system as claimed in claim 4, wherein the yoke (40) pushes a fork (37) mounted on the first and second gear shift rail (34) to push second gear synchronizer sleeve (50).

7. The manual transmission system as claimed in claim 1 or 6, wherein the second gear synchronizer sleeve (50) pushes the second gear synchronizer ring (51) to get partially engage with the rotating counter shaft 2nd gear which is connected with 2nd gear input shaft and apply break on the rotating input shaft (35).

8. The manual transmission system as claimed in claim 4, wherein the lever (39) got disengaged from the rectangular slot (41) of the yoke (40), wherein the partially engagement is disconnected when the reverse gear is shifted.

9. The manual transmission system as claimed in claim 1, wherein the lever (39) has spring to regain its original position after disengagement from the rectangular slot (41) when shifting from reverse to neutral.

10. The manual transmission system as claimed in claim 1, wherein the plurality of gear shift rails (32, 33, 34) are arranged in bottom to top order, wherein at bottom the first and second gear shift rail (34), at middle third and fourth gear shift rail (33), and at top fifth and reverse gear shift rail (32) is present.