[001]The embodiments herein relate to a gear assembly and a method of providing power flow in a power transmission unit.
BACKGROUND
[002] Generally, 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.Conventional output gear (20), hereinafter referred to as gear) includes aplurality of peripheral external gear teeth (20F) provided in constant engagement with another gear mounted to a countershaft, and a plurality of external splines (20E) providedbelow the peripheral external gear teeth(20F) in a lateral direction of the gear(20). The plurality of external splines (20E) of the gear (20) isadapted to be engaged by the dog clutchtherein to transmit the power from the gear (20)to an output shaft. The gear (20) is manufactured as a single piece component and machining the gear (20) to produce external splines (20E) is difficult and is one of the challenges posed to the original equipment manufacturers (OEM's). The gear (20) is complex in design andproducing the external splines (20E) on the gear (20) is difficultand incurs high cost. Usually, manual operated shaping tools are used to machine the gear (20) to produce the external splines (20E) on the gear (20). Smaller shaping tools used for manufacturing of external splines (20E) result in inaccuracy of external splines (20E) whereas bigger shaping tools used for manufacturing of external splines (20E) result in inadvertent interference between the tool and the gear (20) thereby damagingthe gear body.

[003] Therefore, there exists a need for agear assembly and a method of providing power flow in a power transmission unit, which obviates the aforementioned drawbacks.
OBJECTS
[004] The principal object of embodimentsherein is toprovide agear assembly having a gear sleeve connected to a gear.
[005] Another object of embodiments herein is to provide amethod of providing power flow in a power transmission unit.
[006] Another object of embodiments herein is to provide a low range gear assembly having a low range gear sleeve connected to a low range gear, where low range gear sleeve includes a plurality of external splines which is easily manufacturable.
[007] Another object of embodiments herein is to provide a gear assembly, which is easily manufacturable and compact for packaging in same available space in a power transmission unit.
[008] These and other objects of embodimentsherein will be better appreciated and understood when considered in conjunction with following description and 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
[009] The embodiments are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0010] Fig. 1 depicts a cross-sectional view of a conventional gear;
[0011] Fig. 2 depicts a cross-sectional view of agear assembly provided in a power transmission unit, according to embodiments as disclosed herein;
[0012] Fig. 3a depicts a perspective view of a gear of the gear assembly, according to embodiments as disclosed herein;
[0013] Fig. 3b depicts a perspective view of a gear sleeve of the gear assembly, according to embodiments as disclosed herein;
[0014] Fig. 4 depicts a cross-sectional view of the gear assembly, according to embodiments as disclosed herein; and
[0015] Fig. 5 depicts a flowchart indicating a method of providing power flow in the power transmission unit, according to embodimentsas disclosed herein.

DETAILED DESCRIPTION
[0016] 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 aslimiting the scope of the embodiments herein.
[0017] The embodiments herein achieve agear assembly having a gear sleeve connected to a gear, which is easily manufacturable and compact for packaging in a power transmission unit. Further, embodiments herein achieve a method of providing power flow in the power transmission unit. Further, embodiments herein achieve a low range gear assembly having a low range gear sleeve connected to a low range gear, where the low range gear sleeve includes a plurality of external splines which is easily manufacturable.Referring now to the drawings Figs 2 through 5, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0018] Fig. 2 depicts a cross-sectional view of a gear assembly (100) provided in a power transmission unit (10), according to embodiments as disclosed herein. The power transmission unit (10) includes an input shaft (10P), a counter shaft (10C), an output shaft (10S), a plurality of gears (101, 10ID, 10M, 10L and 10H), at least one movable power transmitting member (10MD) and a gear assembly (100). For the purpose of this description and ease of understanding, the power

transmission unit (10) is considered to be a range transmission unit. It is
also within the scope of this invention to consider the power transmission
unit (10) as a multi-speed transmission unit or any other type of
transmission unit. Fig. 4 depicts a cross-sectional view of the gear
5 assembly (100), according to embodiments as disclosed herein. In an
embodiment, the gear assembly (100) includes a gear (102) and a gear sleeve (104). For the purpose of this description and ease of understanding, the gear assembly (100) is considered to be a low range gear assemblywhich is explained herein below with reference to be provided in
10 therange transmission unit (10) of a vehicle. However, it is also within the
scope of this invention to consider the gear assembly (100) as a medium range gear or a high range coupler or any other range gear in the range transmission unit or to consider the gear assembly (100) as a first speed gear, a second speed gear, a third speed gear or any other speed gears in the
15 multi-speed transmission unit of at least one of the vehicle or a machine or
to practice/implement the gear assembly (100) in any other gearbox configurations or any other power transmission units, where manufacturing of external splines (104S, as shown in fig. 3b) on the gear sleeve (104) is easy and packaging in a compact spacein the power transmission unit is
20 required, without otherwise deterring the intended function of the gear
assembly (100) as can be deduced from the description and corresponding drawings.
[0019] For the purpose of this description and ease of
understanding, the input shaft (10I) is considered to be an intermediate
25 shaft, the counter shaft (10C) is considered to be a hollow counter shaft and
the output shaft (10S) is considered to be a range output shaft. However, it is also within the scope of this invention to consider the power transmission unit (10) as the range transmission unit having an input shaft and an output shaft or to consider the power transmission unit (10) as the multi-speed
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transmission unit having an input shaft, an output shaft and with or without countershaft.
[0020] For the purpose of this description and ease of
understanding, the plurality of gears (10I, 10ID, 10M, 10L, 10H) includes
5 an input driving gear (10I) adapted to be integrated with the input shaft
(10P), an input driven gear (10ID) mounted onto the countershaft (10C)
and is driven by the input driving gear (10I), a medium range driving gear
(10M) mounted onto the countershaft (10C), a low range driving gear (10L)
integrated with the countershaft (10C) and is adapted to drive the gear
10 (102), and a high range coupler (10H) adapted to be integrated with the
input shaft (10P).
[0021] The movable power transmitting member (10MD) is movably mounted onto the output shaft (10S). For the purpose of this description and ease of understanding, the movable power transmitting
15 member (10MD) is considered to be a movable medium range gear.
However, it is also within the scope of this invention to consider the movable power transmitting member (10MD) as any of a dog clutch, a synchronizer unit, a gear shifter sleeve and any other type of gear actuating meansaccording to the type and configuration of power transmission units
20 or gearboxes, without otherwise deterring the intended function of the
movable power transmitting member (10MD) as can be deduced from the description and corresponding drawings. The movable power transmitting member (10MD) is moved towards the gear sleeve (104) to facilitate engagement of the movable power transmitting member (10MD) with the
25 gear sleeve (104) therein to transmit the power from the gear (102) to the
output shaft (10S)through gear sleeve (104) and movable power transmitting member (10MD) when the power transmission unit (10) is operated in a low range position. The movable power transmitting member
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(10MD)is moved and engaged with medium range driving gear (10M)
therein to transmit the power from the medium range driving gear (10M) to
the output shaft (10S) when the power transmission unit (10) is operated in
a medium range position. The movable power transmitting member
5 (10MD) is moved towards the high range coupler (10H) to facilitate
engagement of the movable power transmitting member (10MD) with the high range coupler (10H) therein to transmit the power from the high range coupler (10H) to the output shaft (10S) when the power transmission unit (10) is operated in a high range position.
10 [0022] Fig. 3a depicts a perspective view of a gear (102) of the gear
assembly (100), according to embodiments as disclosed herein.The gear (102) is freely mounted on the output shaft (10S) through the gear sleeve (104) and a bush (not shown). The gear (102) includes a plurality of external gear teeth (102E) provided to an outer portion (102P) of the gear
15 (102), and a plurality of internal splines (102I) provided to an inner portion
(102S) of the gear (102).The internal splines (102I) of the gear (102) and external splines (104F) of the gear sleeve (104) are a pair of major diameter fit splines improvingthe alignment of gear (102) and gear sleeve (104). The gear (102) is at least a low range gear.
20 [0023] Fig. 3b depicts a perspective view of a gear sleeve (104) of
the gear assembly (100), according to embodiments as disclosed herein. In an embodiment, the gear sleeve (104) includes a plurality of first external splines (104F) and a plurality of second external splines (104S) spaced away from the first external splines (104F).In an embodiment, the gear
25 sleeve (104) is adapted to transmit power from the gear (102) to the
movable power transmitting member (10MD) which in turn transmits the power to the output shaft (10S) when the gear sleeve (104) is being engaged by the movable power transmitting member (10MD). The gear
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sleeve (104) is adapted to be connected to the gear (102) by spline fitting
the gear sleeve (104) to the gear (102).The gear sleeve (104) is freely
mounted onto the output shaft (10S) through the bush (not shown).
However, it is also within the scope of this invention to connect the gear
5 sleeve (104) with the gear (102) by any of key fitting, adhesive bonding,
snap fitting or by using fasteners or any other means or through any other connecting process, without otherwise deterring the intended function of the gear (102) and the gear sleeve (104) as can be deduced from the description and corresponding drawings. The plurality of first external
10 splines (104F) of the gear sleeve (104) is adapted to be engaged with the
internal splines (102I) of the gear (102).The plurality of second external splines (104S) of the gear sleeve (104) is adapted to be engaged by corresponding internal splines (not shown) of the movable power transmitting member (10MD) when the movable power transmitting
15 member (10MD) is moved towards the gear sleeve (104). The gear sleeve
(104) is at least a low range gear sleeve.
[0024] Fig. 5 depicts a flowchart indicating a method (200) of providing power flow in the power transmission unit (10), according to embodiments as disclosed herein. For the purpose of this description and
20 ease of understanding, the method (200) is explained herein below with
reference to providing power flow in a range transmission unit (10) of a vehicle. However, it is also within the scope of this invention to practice/implement the entire steps of the method (200)in a same manner or in a different manner or with omission of at least one step of the method
25 (200) or with any addition of at least one step to the method (200)for
providing power flow in a multi-speed transmission unit or any other type of transmission unit, without otherwise deterring the intended function of the method (200) as can be deduced from the description and corresponding drawing. In an embodiment, the method (200) includes, allowing power
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flow from an input shaft (10P) to a counter shaft (10C) through an input
driving gear (10I) connected to the input shaft (10P) and an input driven
gear (10ID) mounted to the counter shaft (10C), step 202, allowing power
flow from the counter shaft (10C) to a gear (102) mounted onto an output
5 shaft (10S) through another gear (10L) mounted onto the countershaft
(10C), step 204, allowing power flow from the gear (102) to a gear sleeve (104) connected to the gear (102), step 206, and allowing power flow from the gear sleeve (104) to the output shaft (10S) by engaging a movable power transmitting member (10MD) with the gear sleeve (104) on
10 movement of the movable power transmitting member (10MD) towards the
gear sleeve (104), step 208. The method (200) includes, providing a gear assembly (100) having a gear (102) and a gear sleeve (104) spline fitted to the gear (102) and freely mounted onto the output shaft (10S). Further, the method (200) includes providing the gear sleeve (104) witha plurality of
15 first external splines (104F) and a plurality of second external splines
(104S).
[0025] The working of the gear assembly (100) in conjunction with the method (200) of providing power flow in the power transmission unit (10) is as follows. The input shaft (10P) transmits the power to the counter
20 shaft (10C) through the input driving gear (10I) and the input driven gear
(10ID). Thereafter, the countershaft (10C) transmits the power to the low range gear (102) through the low range driving gear (10L). Thereafter, the low range gear (102) transmits the power to the low range gear sleeve (104) which in turn transmits the power to the range output shaft (10S) when the
25 low range gear sleeve (104) is engaged by the movable medium range gear
(10MD).
[0026] Therefore, a gear assembly (100), whichis easily manufacturable and compact for packaging in a power transmission
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unit(10),is provided. Further, a method (200) of providing power flow in the power transmission unit (10) is provided.
[0027] 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 modifications within the spirit and scope of the embodiments as described herein.

We claim:

A gear assembly (100) in a power transmission unit (10), said gear
assembly (100) comprising:
a gear (102); and
a gear sleeve (104) adapted to be connected to said gear (102),
wherein
said gear sleeve (104) is adapted to transmit power from said gear (102) to a movable power transmitting member (10MD) which in turn transmits the power to an output shaft (10S) when said gear sleeve (104) is being engaged by the movable power transmitting member (10MD).
2. The gear assembly (100) as claimed in claim 1, wherein said gear (102)
includes,
a plurality of external gear teeth (102E) provided to an outer portion (102P) of said gear (102); and
a plurality of internal splines (1021) provided to an inner portion (102S)ofsaid gear (102),
wherein
said plurality of external gear teeth (102E) are provided in constant engagement with gear teeth of corresponding another gear (10L) provided on a countershaft (10C).

3. The gear assembly (100) as claimed in claim 2, wherein said gear sleeve
(104) includes,
a plurality of first external splines (104F) adapted to be engaged with said internal splines (1021) of said gear (102); and
a plurality of second external splines (104S),
wherein
said gear sleeve (104) is adapted to be freely mounted onto the output shaft (10S).
4. The gear assembly (100) as claimed in claim 3, wherein said plurality of said external splines (104S) of said gear sleeve (104) is adapted to be engaged by corresponding internal splines of the movable power transmitting member(lOMD) when said movable power transmitting member (10MD) is moved towards said gear sleeve (104).
5. The gear assembly (100) as claimed in claim 1, wherein said gear assembly (100) is a low range gear assembly;
said gear (102) is a low range gear; and
said gear sleeve (104) is a low range gear sleeve.
6. The gear assembly (100) as claimed in claim 1, wherein the movable
power transmitting member (10MD) is at least a medium range gear.

7. The gear assembly (100) as claimed in claim 1, wherein the power transmission unit (10) is at least a range transmission unit.
8. The gear assembly (100) as claimed in claim 1, wherein said gear assembly (100) is adapted to be packaged in a compact space in the power transmission unit (10).
9. The gear assembly (100) as claimed in claim 2, wherein said gear (102) is adapted to receive power from the countershaft (10C) through corresponding another gear (lOL)provided on the countershaft (10C); and
said countershaft (10C) is adapted to receive power from an input shaft (10P) through an input driving gear (101) connected to the input shaft (10P) and an input driven gear (10ID) mounted on the counter shaft (10C).
10. The gear assembly (100) as claimed in claim 9, wherein the gear (10L) is at least a low range driving gear.
11. A method (200) of providing power flow in a power transmission unit (10), said method (200) comprising:
allowing power flow from an input shaft (10P) to a counter shaft (10C) through an input driving gear (101) connected to the input shaft (10P) and an input driven gear (10ID) mounted on the counter shaft (10C);

allowing power flow from the counter shaft (IOC) to a gear (102) mounted onto an output shaft (10S) through another gear (lOL)provided on the countershaft (IOC);
allowing power flow from the gear (102) to a gear sleeve (104) connected to the gear (102);
allowing power flow from the gear sleeve (104) to the output shaft (10S) by engaging a movable power transmitting member (lOMD)with the gear sleeve(104) on movement of the movable power transmitting member (10MD) towards the gear sleeve (104).
12. The method (200) as claimed in claim, 11, wherein said method (200)
comprising, providing a gear assembly (100) having a gear (102) and a gear
sleeve (104) spline fitted to the gear (102) and freely mounted onto the
output shaft (1 OS),
wherein
the gear (102) is provided with a plurality of internal splines (1021) and a plurality of external gear teeth (102E); and
the gear sleeve (104) is provided with a plurality of first external splines (104F) and a plurality of second external splines (104S).
13. The method (200) as claimed in claim 11, wherein the gear (102) is a
low range gear;
said gear sleeve (104) is a low range gear sleeve;

the movable power transmitting member (10MD) is at least a medium range gear;
the gear (10L) is a low range driving gear;
the power transmission unit (10) is a range transmission unit.
14. A low range gear assembly (100) in a range transmission unit (10), said
low range gear assembly (100) comprising:
a low range gear (102); and
a low range gear sleeve (104) adapted to be connected to said low range gear (102),
wherein
said low range gear sleeve (104) is adapted to transmit power from said low range gear (102) to a movable power transmitting member (10MD) which in turn transmits the power to an output shaft (10S) when said low range gear sleeve (104) is being engaged by the movable power transmitting member (10MD).
15. The low range gear assembly (100) as claimed in claim 14, wherein
said low range gear (102) includes,
a plurality of external gear teeth (102E)provided to an outer portion (102P) of said gear (102); and

a plurality of internal splines (1021) provided to an inner portion (102S)ofsaid gear (102),
wherein
said plurality of external gear teeth (102E) are provided in constant engagement with corresponding gear teeth of a low range driving gear (10L) provided on a countershaft (IOC).
16. The low range gear assembly (100) as claimed in claim 15, wherein
said low range gear sleeve (104) includes,
a plurality of first external splines (104F) adapted to be engaged with said internal splines (1021) of said low range gear (102); and
a plurality of second external splines (104S),
where
said low range gear sleeve (104) is adapted to be freely mounted onto the output shaft (10S).
17. The low range gear assembly (100) as claimed in claim 16, wherein
said plurality of said external splines (104S) of said low range gear sleeve
(104) is adapted to be engaged by corresponding internal splines of the
movable power transmitting member (10MD) when said movable power
transmitting member (10MD) is moved towards said low range gear sleeve
(104).

18. The low range gear assembly (100) as claimed in claim 14, wherein the movable power transmitting member (10MD) is at least a medium range gear.
19. The low range gear assembly (100) as claimed in claim 14, wherein said low range gear assembly (100) is adapted to be packaged in a compact space in the range transmission unit (10).
20. The low range gear assembly (100) as claimed in claim 14, wherein said gear (102) is adapted to receive power from the countershaft (10C) through the low range driving gear (10L) provided on the countershaft (10C); and
said countershaft (10C) is adapted to receive power from an input shaft (10P) through an input driving gear (101) connected to the input shaft (10P) and an input driven gear (10ID) mounted to the counter shaft (10C).