DESC:TECHNICAL FIELD
[001] The embodiments herein relate toa power transmission unit fora vehicle, which comprises a single synchronizer assembly that synchronizes the speed of an output shaft to the speed of an input shaft before the engagement (actuation) of at least one of an odd gear, an even gear and a reverse gear of the power transmission unit.

BACKGROUND
[002] Generally, synchronizer unit in a power transmission unit of a vehicle is used for gradual engagement or dis-engagement of corresponding gears in the power transmission unit. A conventional power transmission unit includes three synchronizer units for five forward speed gears and one reverse speed gear, where one synchronizer unit is used for selecting first gear and second gear, another synchronizer unit is used for selecting third gear and fourth gear, and another synchronizer unit is used for selecting fifth gear and reverse gear. When shifting from third speed gear to second speed gear, a crash noise is generated on contact with the second speed gear due to higher rpm difference between each other. The noise generated in the power transmission unit is un-desirable.
[003] Therefore, there exists a need for a power transmission unit, which obviates the aforementioned drawbacks.

OBJECTS

[004] The principal object of an embodiment of this invention is toprovide a power transmission unit of a vehicle, which comprises a single synchronizer assembly that synchronizes the speed of an output shaft to the speed of an input shaft before the engagement (actuation) of at least one of an odd gear, an even gear and a reverse gear of the power transmission unit.
[005] Another object of an embodiment of this invention is to provide a power transmission unit of a vehicle, which comprises a single synchronizer assembly that synchronizes the speed of an output shaft to the speed of an input shaft for 5 forward speed gears and reverse speed gear.
[006] Another object of an embodiment of this invention is to provide a power transmission unit of a vehicle, which comprises a plurality of stoppers that restricts the movement of corresponding shift fork on excess movement of corresponding shift rail, therein to restrict the movement of a synchronizer sleeve of a single synchronizer assemblyimmediately after synchronization of speed of an output shaft to the speed of an input shaft of the power transmission unit.
[007] Another object of an embodiment of this invention is to provide a power transmission unit of a vehicle, which isintegrated/disposed inside an engine between a left-hand side crankcase housing and a right-hand side crankcase housing.
[008] Another object of an embodiment of this invention is to provide a power transmission unit of a vehicle, which comprises an integrated second and fifth driving gear, a third driven gear and a fourth driven gear which are acting as dog clutches/shifter sleeves to facilitate engagement of corresponding gears based on the movement of a gear shift lever adapted to be shifted to corresponding gear position.
[009] Another object of an embodiment of this invention is to provide a power transmission unit with a H-gate shift pattern.
[0010] Another object of an embodiment of this invention is to provide a power transmission unit for a vehicle, which is compact and has less weight.
[0011] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF DRAWINGS
[0012] The embodiments of the invention are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0013] Fig. 1 depicts a cross-sectional view of a power transmission unit a vehicle, according to an embodiment of the invention as disclosed herein;
[0014] Fig. 2 depicts a cross-sectional view of a portion of a synchronizer assembly of the power transmission unit, according to an embodiment of the invention as disclosed herein;
[0015] Fig. 3 depicts a perspective view of a portion of the power transmission unit, according to an embodiment of the invention as disclosed herein; and
[0016] Fig. 4 depicts a cross-sectional view of a portion of the power transmission unit, according to an embodiment of the invention as disclosed herein.

DETAILED DESCRIPTION
[0017] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0018] The embodiments herein achieve a power transmission unit of a vehicle, which comprises a single synchronizer assembly that synchronizes the speed of an output shaft to the speed of an input shaft before the engagement (actuation) of at least one of an odd gear, an even gear and a reverse gear of the power transmission unit. Referring now to the drawings, and more particularly to Figs. 1 through 4, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0019] Fig. 1 depicts a cross-sectional view of a power transmission unit 10 of a vehicle, according to an embodiment of the invention as disclosed herein. Fig. 2 depicts a cross-sectional view of a portion of a synchronizer assembly 100 of the power transmission unit 10, according to an embodiment of the invention as disclosed herein. In an embodiment, the power transmission unit 10 includes a single synchronizer assembly 100, a plurality of stoppers 200 (as shown in fig. 3), an input shaft 12, an output shaft 14, a first driving gear 16, anintegrated second and fifth driving gear 18, a third driving gear 20, a fourth driving gear 22, a reverse driving gear 24, a first driven gear 26, a second driven gear 28, a third driven gear 30, a fourth driven gear 32, a fifth driven gear 34, a reverse driven gear 36, a reverse idler gear, a reverse idler shaft (not shown), a plurality of shift forks (not shown), a plurality of shift rails (not shown) and may include other standard components as present in a standard power transmission unit. The synchronizer assembly 100 includes a synchronizer hub 102, a synchronizer sleeve 104, at least one synchronizer ring 106, a plurality of synchronizer ring actuating members 108 and may include other standard components as present in a standard power transmission unit. In an embodiment, the power transmission unit 10 is a manual power transmission unit configured to be provided with a H gate shift pattern. It is also within the scope of the invention to provide the power transmission unit 10 as an automatic power transmission unit, automated manual power transmission unit or any other power transmission unit incorporating any other type of shifting mechanisms. For the purpose of this description and ease of understanding, the power transmission unit 10 is explained herein below with reference to be provided in a vehicle. However, it is also within the scope of the invention to implement/practice the power transmission unit 10 in any other machines and any other systems without otherwise deterring the intended function of the power transmission unit 10 as can be deduced from the description and corresponding drawings.
[0020] The synchronizer assembly 100 is rotatably mounted onto the output shaft 14 between the second driven gear 28 and the fifth driven gear 34. The synchronizer hub 102 of the synchronizer assembly 100 is rotatably mounted onto the output shaft 14 between the second driven gear and fifth driven gear. The synchronizer sleeve 104 is slidably connected to the synchronizer hub 104. The synchronizer ring 106 is movably connected to the synchronizer hub 102.Each synchronizer ring actuating member 108 is movably connected to the synchronizer hub 102, the synchronizer sleeve 104 and the synchronizer ring 106 of the synchronizer assembly 100.At least a portion of each synchronizer ring actuating member 108 is adapted to movably engage corresponding synchronizer ring 106 to move corresponding synchronizer ring 106 to engage corresponding gear 28 to synchronize the speed of the output shaft 14 to the speed of the input shaft 12 on movable engagement of the synchronizer sleeve 104 with each synchronizer ring actuating member 108 before the engagement of at least one of an odd gear, an even gear and a reverse gear. The odd gear is at least one of the first driven gear 26 (first speed gear), the third driving gear 20 (third speed gear) and the fifth driven gear 34 (fifth speed gear). The even gear is at least one of the second driven gear 28 (second speed gear) and the fourth driving gear 22 (fourth speed gear). The reverse gear is a reverse driven gear 36 (reverse speed gear).
[0021] The plurality of stoppers 200 are supported by a transmission housing H (as shown in fig. 3) and extends in a direction towards corresponding shift fork S, where the shift fork S is mounted to corresponding shift rail R and positioned between stoppers 200. Each stopper 200 is adapted to restrict the movement of corresponding shift fork S on excess movement of shift rail R (as shown in fig. 4), therein to restrict the movement of synchronizer sleeve 104 immediately after the engagement of synchronizer ring 108 with corresponding gear 28 to restrict the wear and tear of synchronizer ring 106 and corresponding gear 28. The shift fork S defines a portion Sp (as shown in fig. 4) adapted to engage at least one of the stoppers 200 to restrict the movement of the shift fork S during excess travel of the shift rail R.
[0022] The input shaft 12 is rotatably connected to a crankshaft of an engine (not shown) through a clutch unit (not shown). The output shaft 14 is rotatably connected to the input shaft 12 of the power transmission unit 10. The first driving gear 16 is integrated with the input shaft 12. It is also within the scope of the invention to provide the first driving gear 16 as a separate part mounted to the input shaft 12.
[0023] The integrated second and fifth gear 18 is movably connected to the input shaft 12 between the third driving gear 20 and the fourth driving gear 22. The integrated second and fifth gear 18 includes a second driving gear 18S, a fifth driving gear 18F and a fork engaging portion (not shown).The integrated second and fifth gear 106 acts/serves as a dog clutch to facilitate engagement of the third driving gear 20 and the fourth driving gear 22 on engagement of a gear shift lever (not shown) adapted to be shifted to a third gear position and a fourth gear position respectively. The second driving gear 18S of the integrated second and fifth gear 18 is adapted to drive the second driven gear 28 and also acts/serves as a dog clutch to facilitate engagement of the third driving gear 20 on engagement of the gear shift lever (not shown) adapted to be shifted from a neutral gear position to the third gear position. The fifth driving gear 18F of the integrated second and fifth gear 18 is adapted to drive the fifth driven gear 34 and also acts/serves as dog clutch to facilitate engagement of the fourth driving gear 22 on engagement of the gear shift lever (not shown) adapted to be shifted from the neutral gear position to the fourth gear position.
[0024] The third driving gear 20 is mounted to the input shaft 12 between the first driving gear 16 and the second driving gear 18S of the integrated second and fifth gear 18.The third driving gear 20 is adapted to drive the third driven gear 30 which is mounted onto the output shaft 14.
[0025] The fourth driving gear 22 is mounted to the input shaft 12 between the fifth driving gear 18F of the integrated second and fifth gear 18 and the reverse driving gear 24. The fourth driving gear 22 is adapted to drive the fourth driven gear 32 which is mounted to the output shaft 14.
[0026] The reverse driving gear 24 is mounted to the input shaft 12 adjacent to the fourth driving gear 22. The reverse driving gear 24 is adapted to drive the reverse driven gear 36 through the reverse idler gear (not shown) adapted to be mounted to the reverse idler shaft (not shown).
[0027] The first driven gear 26 is mounted to the output shaft 14 and rotatably connected to the first driving gear 16, where the first driven gear 26 is driven by the first driving gear 16. The second driven gear 28 is mounted to the output shaft 14 and rotatably connected to the second driving gear 18S of the integrated second and fifth gear 18. The second driven gear 28 is driven by the second driving gear 18S of the integrated second and fifth gear 18.
[0028] The third driven gear 30 is movably connected to the output shaft 14 between the first driven gear 26 and the second driven gear 28, and rotatably connected to the third driving gear 20. The third driven gear 30 is driven by the third driving gear 20 and also acts/serves as dog clutch to facilitate engagement of the first driven gear 26 and the second driven gear 28 on engagement of the gear shift lever (not shown) adapted to be shifted to the first gear position and the second gear position respectively.
[0029] The fourth driven gear 32 is movably connected to the output shaft 14 between the fifth driven gear 34 and the reverse driven gear 36, and rotatably connected to the fourth driving gear 22. The fourth driven gear 32 is driven by the fourth driving gear 22 and also acts/serves as dog clutch to facilitate engagement of the fifth driven gear 34 and the reverse driven gear 36 on engagement of the gear shift lever (not shown) adapted to be shifted to a fifth gear position and a reverse gear position respectively.
[0030] The fifth driven gear 34 is mounted to the output shaft 14 between the synchronizer assembly 100 and the fourth driven gear 32, and rotatably connected to the fifth driving gear 18F of the integrated second and fifth gear 18. The fifth driven gear 34 is driven by the fifth driving gear 18F of the integrated second and fifth driving gear 18.
[0031] The reverse driven gear 36 is mounted to the output shaft 14 adjacent to the fourth driven gear 32 and rotatably connected to the reverse driving gear 24 through the reverse idler gear (not shown). The reverse driven gear 36 is driven by the reverse driving gear 24.
[0032] Therefore, a power transmission unit 10 for a vehicle, which comprises single synchronizer assembly 100 that synchronizes the speed of an output shaft 14 to the speed of an input shaft 12 before the engagement (actuation) of at least one of an odd gear, an even gear and a reverse gear of the power transmission unit is provided.
[0033] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
,CLAIMS:We claim,
1. A power transmission unit 10 comprising:
a plurality of stoppers 200 adapted to be extending in a direction towards corresponding shift fork S, where said shift fork S is mounted to corresponding shift rail R and positioned between said stoppers 200; and
a synchronizer assembly 100 comprising a synchronizer sleeve 104 adapted to be slidably connected to a synchronizer hub 102,at least one synchronizer ring 106,and a plurality of synchronizer ring actuating members 108,
wherein
at least a portion of each of said synchronizer ring actuating member 108 is adapted to movably engage corresponding said synchronizer ring 106 to move corresponding said synchronizer ring 106 to engage corresponding gear 28 to synchronize the speed of an output shaft 14 to the speed of an input shaft 12on movable engagement of said synchronizer sleeve 104 with each of said synchronizer ring actuating member 108 before the engagement of at least one of an odd gear, an even gear and a reverse gear.

2. The power transmission unit 10 as claimed in claim 1, wherein each of said stopper 200 is adapted to restrict the movement of corresponding said shift fork S on excess movement of said shift rail R, therein to restrict the movement of said synchronizer sleeve 104 immediately after the engagement of said synchronizer ring 108 with corresponding said gear 28.

3. The power transmission unit 10 as claimed in claim 1, wherein said synchronizer assembly 100 is rotatably mounted onto said output shaft 14 between a second driven gear 28 and a fifth driven gear 34.

4. The power transmission unit 10 as claimed in claim 1, wherein each of said stopper 200 is supported by a transmission housing H.

5. The power transmission unit 10 as claimed in claim 1, wherein said odd gear is at least one of a first driven gear 26, a third driving gear 20 and fifth driven gear 34.

6. The power transmission unit 10 as claimed in claim 1, wherein said even gear is at least one of a second driven gear 28 and a fourth driving gear 22,
wherein said reverse gear is a reverse driven gear 36.

7. The power transmission unit 10 as claimed in claim 1 is configured to be provided in a vehicle.