FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
[See section 10 and rule 13]
TITLE: “A HUB ASSEMBLY WITH A BYPASS HUB FOR A VEHICLE AND AN
OPERATION METHOD THEREOF”
NAME AND ADDRESS OF THE APPLICANT:
TATA MOTORS LIMITED, having address at Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400 001 Maharashtra, India.
Nationality: INDIAN
The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD:
Present disclosure generally relates to a field of automobiles. Particularly, but not exclusively, the present disclosure relates to hub assembly for an axle shaft of a vehicle for selectively transmitting required amount of torque to wheels of the vehicle connected to the hub assembly.
BACKGROUND OF DISCLOSURE:
Automobiles includes a power transmission mechanism to transmit power generated by an engine to wheels in form of speed and torque to propel the vehicle. A propeller shaft may be connected to a rear axle shaft (s) through a differential or to the front axles. The rear axle shaft (s) are disposed within a rear axle beam and the differential is also mounted on the rear axle beam. The torque generated by an output shaft of the engine is transmitted from the propeller shaft to the rear axle shaft (s) through a pinion and a crown wheel of the differential. The torque from the crown wheel is further divided and transmitted to a left axle shaft and a right axle shaft connected to the differential. In case of electrically driven vehicles, an electric motor is directly connected to the rear axle shaft (s) for torque transmission to the wheels. A hub assembly may be mounted on each axle shaft and connected/bolted to the rear axle beam. The hub assembly is configured to transmit the torque from the rear axle shaft (s) to the wheels. The demand of torque is also proportional to load on the vehicle. However, during movement of the vehicle on a gradient such as a declining surface or a flat surface, such torque may not be necessary.
Conventionally, the hub assembly includes a wheel hub and a housing rotatably connected to the wheel hub. A planetary gear train is disposed in the housing and rotatably coupled to the rear axle shaft (s) to transmit the torque from the rear axle shaft (s) to the wheels through the wheel hub. The planetary gear train reduces speed of the wheels and provides more torque to the wheels. The planetary gear train is continuously operated to produce a constant amount of torque to the wheels depending on capacity of the engine or type of the vehicle. However, this torque transmission from the rear axle shaft to the wheels of the vehicle remains constant even when the vehicle is moving on a flat or slope surface. Consequently, this may increase rolling losses and prove detrimental to fuel economy of the vehicle. Also, the life of the hub assembly is reduced and may require frequent maintenance of the planetary gear train which is not economical.

The present disclosure is intended to overcome one or more above stated limitations.
SUMMARY OF THE DISCLOSURE:
One or more shortcomings of conventional hub assemblies are overcome, and additional advantages are provided through a hub assembly and a method of operating the same of the present disclosure. Additional features and advantages are realized through the construction and arrangement of the components of the hub assembly and the method to selectively transmit variable torque to the rear axle of the shaft base on the requirement. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
In one non-limiting embodiment of the present disclosure, a hub assembly for an axle shaft of a vehicle is disclosed. The hub assembly comprises a housing and a planetary gear set disposed within the housing. The planetary gear set is concentrically mounted on the axle shaft. A bypass hub is rotatably connected to the housing. The bypass hub comprises a casing and a gear is disposed within the casing and positioned at one end of the axle shaft. A clutch is movably disposed within the casing between the planetary gear set and the gear. The clutch is configured to selectively engage and disengage with the planetary gear set and the gear. Further, an actuator is configured to displace the clutch between a first position and a second position. The clutch is configured to selectively engage with the planetary gear set in the first position and engage the gear in the second position for variable torque transmission.
In an embodiment, the planetary gear set comprises a sun gear rotatably coupled to the axle shaft. A ring gear having a plurality of planet gears radially arranged within the ring gear. The plurality of planet gears are meshed in between the ring gear and the sun gear and connected to the housing. The plurality of planet gears are configured to actuate the housing to transmit torque from the axle shaft to the wheels of the vehicle.
In an embodiment, the planetary gear set transmits a first predetermined torque from the axle shaft to the wheels.

In an embodiment, the gear transmits a second predetermined torque less than the first predetermined torque from the axle shaft to the wheels.
In an embodiment, the clutch is circumferentially defined with a plurality of teeth extending in an axial direction to selectively engage with the sun gear and engage the gear in the first position and the second position.
In an embodiment, the actuator comprises at least one cylinder disposed within the casing. The at least one cylinder is in fluid communication with a reservoir containing pressurized air. A piston is slidable within the at least one cylinder and is defined with a lever at one end and the lever is connected to the clutch to linearly displace the clutch within the housing. The at least one cylinder receives the pressurized air to actuate the piston within the at least one cylinder for displacement of the clutch.
In an embodiment, the hub assembly comprises a control unit communicatively coupled with the actuator. The control unit is configured to selectively actuate the actuator based on a plurality of parameters for torque transmission.
In an embodiment, the plurality of parameters include speed of the vehicle, load on the vehicle, steepness of a road.
Present disclosure also discloses a bypass hub for a hub assembly mounted on an axle shaft of a vehicle. The bypass hub comprises a casing connectable to the hub assembly. The hub assembly (100) comprises a housing (104) and a planetary gear set (106) disposed within the housing. A gear is disposed within the casing and positioned at one end of the axle shaft. A clutch is movably disposed within the casing between the planetary gear set and the gear. The clutch is configured to selectively engage and disengage with the planetary gear set and the gear. Further, an actuator is configured to displace the clutch between a first position and a second position. The clutch is configured to selectively engage with the planetary gear set in the first position and engage the gear in the second position for variable torque transmission.
In one non-limiting embodiment a method of operation of the hub assembly connected to an axle shaft of the vehicle for the variable torque transmission is disclosed. The method comprises

the steps of initially determining at least one first parameter of a plurality of parameters by a control unit. Actuating the actuator, by the control unit, to displace a clutch to a first position for a first predetermined torque transmission from the axle shaft to wheels of the vehicle. The clutch is configured to engage with a planetary gear set in the first position. Later, the control unit determines at least one second parameter and de-actuates the actuator to disengage the clutch with the planetary gear set to restrict torque transmission from the axle shaft to the wheels. Further, the control unit determines at least one third parameter and actuates the actuator to displace the clutch to a second position for a second predetermined torque transmission from the axle shaft to the wheels. The clutch is configured to engage with a gear in the second position. Lastly, the control unit de-actuates the actuator to disengage the clutch with the gear to restrict torque transmission from the axle shaft to the wheels.
In an embodiment, the at least one first parameter and the at least one second parameter and the at least one third parameter of the plurality of parameters is selected from a speed of the vehicle, load on the vehicle, steepness of a road +++.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following description.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS:
The novel features and characteristics of the disclosure are set forth in the appended description. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following description of an illustrative embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:
Fig. 1 illustrates a sectional view of a hub assembly connected to an axle shaft of a vehicle, in accordance with an embodiment of the present disclosure.

Fig. 2 illustrates an exploded view of the hub assembly and the axle shaft, in accordance with an embodiment of the present disclosure.
Fig. 3 illustrates a sectional view of the hub assembly in a first position, in accordance with an embodiment of the present disclosure.
Fig. 4 illustrates a sectional view of the hub assembly in a second position, in accordance with an embodiment of the present disclosure.
Fig. 5 is a flow diagram depicting a method of operating the hub assembly having the bypass hub, in accordance with an embodiment of the present disclosure.
Fig. 6 is a schematic block diagram depicting the control unit and components communicatively coupled to the control unit, in accordance with an embodiment of the present disclosure.
Fig. 7 is a top view of an electrically driven vehicle having the hub assembly, in accordance with an embodiment of the present disclosure.
Fig. 8 is a top view of the vehicle having the hub assembly, in accordance with an embodiment of the present disclosure.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily 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.
DEATAILED DESCRIPTION:
While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

It is to be noted that a person skilled in the art would be motivated from the present disclosure and modify a device and a system of any vent assembly for the purpose of directing the airflow in various directions inside the vehicle. However, such modification should be construed within the scope of the present disclosure. Accordingly, the drawings show only those specific details that are pertinent to understand the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
The terms “comprises”, “comprising”, or any other variations thereof used in the present disclosure, are intended to cover a non-exclusive inclusion, such that an assembly, a method, an apparatus or a device,that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such assembly and the method. In other words, one or more elements in the assembly and the method preceded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the assembly and the method.
In the following description of the embodiments of the disclosure, reference is made to the accompanying figures that form a part hereof, and in which are shown, by way of illustration, specific embodiments in which the present disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present disclosure, and it is to be understood that other embodiments may be utilized and that, changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
Embodiments of the present disclosure discloses a hub assembly for an axle shaft of a vehicle for variable torque transmission to wheels of the vehicle based on the requirement. Conventionally, the planetary gear train of the hub assembly transmits the torque from the axle shaft to the wheels. The planetary gear train is rotatably coupled to the rear axle shaft to reduce speed and produce more torque for the wheels. The planetary gear train is continuously operated to produce a constant amount of torque to the wheels depending on capacity of the engine or type of the vehicle. However, this torque transmission from the rear axle shaft to the wheels of the vehicle remains constant even when the vehicle is moving on a flat or slope surface. Consequently, this may

increase rolling losses and prove detrimental to fuel economy of the vehicle. Also, the life of the hub assembly is reduced and may require frequent maintenance of the planetary gear train which is not economical.
In view of the above, a hub assembly for an axle shaft of a vehicle is disclosed. The hub assembly comprises a housing and a planetary gear set disposed within the housing. The planetary gear set is concentrically mounted on the axle shaft. A gear is disposed within the housing and positioned at one end of the axle shaft. A clutch is movably disposed within the housing between the planetary gear set and the gear. The clutch is configured to selectively engage and disengage with the planetary gear set and the gear. Further, an actuator is configured to displace the clutch between a first position and a second position. The clutch is configured to selectively engage with the planetary gear set in the first position and engage the gear in the second position for variable torque transmission. This configuration of the clutch enables to provide optimum torque from the axle shaft to the wheels as per the requirement. The torque is provided by the planetary gear set upon movement of the clutch to the first position when the vehicle is travelling on a gradient. Further, when the vehicle is moving on a flat surface, the torque is reduced upon movement of the clutch to the second position such that the torque is directly transmitted from the axle shaft to the wheels through a single gear to increase speed of the vehicle. Lastly, when the vehicle is travelling on an incline or a slope, the clutch remains in a neutral position such that the power from the engine is directly transmitted from the axle shaft to the wheels to completely eliminate the torque and increase speed of the vehicle. Advantageously, this prevents rolling losses in the planetary gear train and improves fuel economy of the vehicle. Also, the life of the hub assembly may be significantly increased. Further, the hub assembly is simple in construction and includes less number of components. This reduces cost of manufacturing and maintenance of the hub assembly.
Referring to Fig. 1 and Fig. 2 which illustrates a sectional and perspective views of the hub assembly (100) for an axle shaft (102) of the vehicle (200), in accordance with an embodiment of the present disclosure. The axle shaft (102) is connected to an axle beam (102a) upon which the differential (206) is mounted (as shown in Fig. 8). In an embodiment, the axle shaft (102) may be coupled to an E-motor (204) at one end (as shown in Fig. 9) and an other end of the axle shaft (102) is mounted to a planetary gear set (106) in case of an electrically driven vehicles. The hub

assembly (100) comprises a wheel hub (109) and a housing (104) connected to the wheel hub (109). The housing (104) is disposed on an axis (A-A) defined in an axial direction of the axle shaft (102). The housing (104) may be manufactured of stainless steel and alloys of steel. The housing (104) is defined with a first flange (104a) extending along a circumference of the housing (104) at one end. The first flange (104a) is defined with a plurality of first holes (104b). The wheel hub (109) is connected at the one end of the housing (104) and a wheel (202) of the vehicle (200) is mounted on a juncture of the wheel hub (109) and the housing (104). The wheel hub (109) is configured to absorb load acting from vehicle (200) while allowing transmitting power from axle shaft (102) to the wheel (202) for rotation. The wheel hub (109) is defined with a second flange (109a) extending along the circumference of the wheel hub. The second flange (109a) is defined with a plurality of second holes (109b) aligned with the plurality of first holes (104b) to receive a plurality of fasteners (111) to rotatable couple the wheel hub (109) to the housing (104). The wheel hub (109) includes at least one bearing (113) defined axially within the wheel hub (109). The at least one bearing (113) is configured to allow rotation of the wheel hub (109) along the axle shaft (102) and absorbs axial loads that are transmitted from the wheels (202) to the axle beam (102a). A plurality of oil seals (115) is equipped within the wheel hub (109) surrounding the at least one bearing (113, 113a) to avoid leakage of a lubricant from the wheel hub (109). A pole wheel (117) is rotatably connected to the wheel hub (109) at one end opposite the first flange (104a). The pole wheel (117) is communicatively coupled with a sensor (not shown in Figs.) associated with a braking system (not shown in Figs.) of the vehicle (200). The pole wheel (117) is configured to determine the number of rotations of the wheel hub (109) or a speed of the wheel hub (109) to generate a signal for braking activating the braking system. A planetary gear set (106) disposed within the housing (104).
The planetary gear set (106) is concentrically mounted on the axle shaft (102). The planetary gear set (106) comprises a sun gear (114) rotatably coupled to the axle shaft (102) through a needle bearing (119). This cannot be construed as a limitation and any type of bearing such as a roller bearing, thrust bearing etc. may be used to allow rotation of the sun gear (114) with reduced friction. The sun gear (114) is defined with an external gear teeth (114a) along an outer circumference of the sun gear (114). One end of the sun gear (114) is defined with a plurality of dog teeth (114b) along the circumference. A ring gear (116) is mounted around the sun gear (114)

and defined with an internal gear teeth (not shown in Figs.) or internal splines along the circumference of the ring gear (116). The ring gear (116) is fixed in position by an adaptor (121). The adaptor (121) is defined with an external splines (123) on its outer circumference and is configured to mesh with a portion of the internal gear teeth of the ring gear (116). The adaptor (121) is configured to fix the ring gear (116) in position with respect to the axle shaft (102). In an embodiment, a lock nut (125) is provided to connect the adaptor (121) to the ring gear (116) to restrict axial movement of the ring gear (116). In an embodiment, a bearing (127) may be disposed between the adaptor (121) and the axle shaft (102). A plurality of planet gears (118) are radially arranged within the ring gear (116). Each planet gear (118) of the plurality of planet gears (118) are meshed with the internal gear teeth of the ring gear (116) and the external gear teeth (114a) of the sun gear (114). In an embodiment, a plurality of planet pins (118a) are disposed within each planet gear of the plurality of planet gears (118) to facilitate uniform rotation of the plurality of planet gears (118). The plurality of planet gears (118) rotate within the ring gear (116) about the internal splines of the ring gear (116) and the ring gear (16) is fixedly connected to the adaptor (121). A planet carrier (120) may be connected to each of the plurality of planet gears (118). The planet carrier (120) is fixed to the housing (104) and is configured to rotate the housing (104). The rotation of the sun gear (114) drives each planet gear (118) of the plurality of planet gears (118) to rotate the planet carrier (120) about the axis (A-A). This rotation of the planer carrier (120) actuates the housing (104) and the wheel hub (109) to transmit a first predetermined torque (T1) from the axle shaft (102) to the wheel or wheels (202) of the vehicle (200).
The hub assembly (100) further comprises a bypass hub (105) rotatably connected to the housing (104) at another end opposite to the wheel hub (109). The bypass hub (105) comprises a casing (107) defined with a third circumferential flange (131) connectable to a portion of the housing (104) at the other end. The bypass hub (105) is fastened to the housing (104) about the third circumferential flange (131) through a suitable fastening mechanism such as a bolt and nut, studs, screws etc. A gear (108) is disposed within the bypass hub (105) and splined to the casing (107) of the bypass hub (105). The gear (108) is positioned at an other end of the casing (107) opposite to the sun gear (114). The gear (108) is defined with a plurality of gear teeth (108a) extending in an axial direction along the axis (A-A) towards the sun gear (114). The gear (108) is configured to transmit torque from the axle shaft (102) to the casing (107) of the bypass hub (105). The casing

(107) further rotates the bypass hub which in turn actuates the housing (104) to rotate the wheel hub (109). The torques is finally transmitted to the wheels (202) of the vehicle (200) through the wheel hub (109). In other words, the rotation of the gear (108) actuates the bypass hub (105) to rotate the housing (104) for transmitting torque from the axle shaft (102) to the wheels (202). The gear (108) is configured to transmit a second predetermined torque (T1) which is less than the first predetermined torque (T2) transmitted to the wheels (202). A clutch (110) is movably disposed within the housing (104) between the planetary gear set (106) and the gear (108). The clutch (110) is rotationally mounted on the axle shaft (102) and is also slidable on the axle shaft (102) along the axis (A-A). The clutch (110) is displaced between a first position (FP) and a second position (SP). The clutch (110) is configured to selectively engage and disengage with the planetary gear set (106) and the gear (108) for variable torque transmission from the axle shaft (102) to the wheels (202) of the vehicle (200). The clutch (110) is defined with a plurality of first gear teeth (133) and a plurality of second gear teeth (135) extending from either end faces of the clutch (110). The plurality of first gear teeth (133) is configured to engage with the plurality of dog teeth (114b) of the sun gear (114) in the first position (FP). The plurality of second gear teeth (135) engages with the plurality of gear teeth (108a) of the gear (108) in the second position (SP). The bypass hub (105) further comprises an actuator (112) configured to displace the clutch (110) between the first position (FP) and a second position (SP). The actuator (112) comprises at least one cylinder (122) disposed within the casing (107). In an embodiment, the at least one cylinder (122) is disposed preferably at a top end of the casing (102) in parallel to the axis (A-A). A piston (124) is slidably disposed within the at least one cylinder (122). The at least one cylinder (122) is in fluid communication with a reservoir (137) containing pressurized air. In an embodiment, the reservoir (137) may be mounted outside the hub assembly (100) and connected to the at least one cylinder (122) through a plurality of hoses (138). The plurality of hoses (138) includes a first hose (138a) and a second hose (138b). The first hose (138a) is connected at a rear end of the piston (124) to supply the pressurized air for displacement of the piston (124) in a forward direction. The second hose (138b) is connected at a front end of the piston (124) to supply the pressurized air for displacement of the piston (124) in a backward direction. The piston (124) is defined with a lever (126) at one end and a resilient member (140) is mounted at and other end of the piston (124). The shifter fork (126) extends downwardly from the piston (124) and is connected to the clutch (110) to linearly displace the clutch (110) in the first position (FP) and the second position (SP). The at

least one cylinder (122) receives the pressurized air from the reservoir to actuate the piston (124) within the at least one cylinder (122) for displacement of the clutch (110) between the first and second positions (FP, SP).
The bypass hub (105) further comprises a control unit (130) communicatively coupled with the actuator (112). The control unit (130) is configured to selectively actuate the actuator (112) based on a plurality of parameters for torque transmission. The plurality of parameters includes speed of the vehicle, load on the vehicle, steepness of a road etc. As an example, the control unit (130) continuously monitors a speed of the vehicle (200) through a speed sensor (not shown in Figs.) associated with a vehicle control system. If there is a sudden change in speed of the vehicle (200), the control unit (130) determines that there is a requirement of torque and subsequently actuates the actuator (112) to displace the clutch (110) to the first position (FP). This activates the planetary gear set (106) to provide required torque to the vehicle (200). The control unit (130) is programmable to set various conditions of the vehicle (200) to provide optimum torque in a varied manner. In an embodiment, the control unit (130) may be an onboard vehicle electronic control unit (VECU).
An operative configuration of the hub assembly (100) for transmission of variable torque is now explained with reference to Figs. 1, Fig. 3, and Fig. 4. Each operation mode is termed as a hub reduction mode (100a), hub disconnect mode (100b) and a hub direct drive mode (100c). The hub reduction mode (100a) and the hub direct drive (100c) mode are configured to transmit variable torque from the axle shaft (102) to the wheels (202) based on the requirement. The hub disconnect mode (100b) is configured to restrict torque transmission from the axle shaft (102) to the wheels (202) such that the wheels (202) can be rotated freely to increase speed of the vehicle (200). The hub direct drive mode (100c) freely rotates the axle shaft (102) and the torque is not transmitted to the wheels (202). The planetary gear set (106) is not in operating condition in the hub direct drive mode (100c).
Hub reduction mode (100a): Referring to Fig. 5, at step 401, the control unit (130) determines at least one first parameter (P1) which may correspond to a sudden change or decrease in speed of the vehicle (200) due to a steep incline or a gradient surface. Upon determining this condition, at step 402, the control unit (130) activates the actuator (112) to displace the clutch (110) from a

neutral position (NP) to the first position (FP) for a first predetermined torque transmission from the axle shaft (102) to the wheels (202). The clutch (110) engages the sun gear (114) of the planetary gear set (106) which further rotates the plurality of planet gears (118) and the housing
(104) through the planet carrier (120). The planet carrier (120) rotates the housing (104) and thus
the first predetermined torque (T1) is transmitted from the axle shaft (102) to the wheels (202).
This torque helps to move the vehicle (200) up the gradient.
Hub disconnect mode: In this mode, if the vehicle (200) is travelling at higher speed, at step (403) the control unit (130) determines at least one second parameter (P2) corresponding to a constant increase in a speed of the vehicle (200). In an embodiment, the control unit (130) may determine a condition that the vehicle (200) is travelling on a slope. Thus, the clutch (110) in the bypass hub
(105) remains in the neutral position (NP) between the planetary gear train (106) of the housing
(104) and the gear (108). If the clutch (110) is in the first position (FP), at step (404), the control
unit (130) actuates the clutch (110) to disengage from the planetary gear set (106) to the neutral
position (NP). Further, if the clutch (110) is in the second position (SP), then at step (406), the
control unit (130) actuates the actuator to disengage the clutch (110) from the gear (108) to the
neutral position (NP). Therefore, no torque is transmitted to the wheels (202) of the vehicle (200)
and the axle shaft (102) rotates freely due to inertia of the vehicle (200).
Hub direct drive mode (100c): Again, referring to Fig. 5, at step 405, the control unit (130) determines at least one third parameter (P3) corresponding to the increase in speed of the vehicle (200) after passing through the gradient. In an embodiment, the control unit (130) may determine a constant increase in speed of the vehicle (200). Consequently, the control unit (130) activates the actuator (112) the displace the clutch (110) to the second position (SP). The clutch (110) engages with the gear (108) and the torque on the axle shaft (102) is directly transmitted to the wheels (202) of the vehicle (200). The gear (108) rotates along with the bypass hub (105) which further rotates the housing (104) of the hub assembly (100) to transmit the second predetermined torque to the wheels (202). In this mode, the planetary gear set (106) is completely bypassed by the gear (108) within the bypass hub (105). This provides more speed to the wheels (202) and also improves the life of the hub assembly (100), as the planetary gear set (106) is not operated continuously.

The hub assembly (100) of the present disclosure is simple in construction and is retrofittable to any type of vehicles based on the requirement.
The bypass hub (105) of the present disclosure may be installed to conventional wheel hub assemblies of the vehicles to enable variable torque transmission. This enables optimum torque transmission to the wheels (202) and improves fuel economy pf the vehicle.
The hub assembly (100) of the present disclosure includes a lesser number of components. This reduces manufacturing and maintenance costs of the hub assembly (100).
EQUIVALENTS
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting.
Reference numerals:

Part Numeral
Hub assembly 100
Vehicle 200
Wheels 202
E-motor 204
Differential 206
Method 400
Axle shaft 102
Axle beam 102a

Housing 104
First flange 104a
A plurality of first holes 104b
Planetary gear set 106
Casing 107
Gear 108
Wheel hub 109
Second flange 109a
Plurality of second holes 109b
Clutch 110
Plurality of fasteners 111
Actuator 112
At least one bearing 113
Sun gear 114
External gear teeth 114a
Plurality of dog teeth 114b
A plurality of oil seals 115
Ring gear 116
Outer surface 116a
Pole wheel 117
A plurality of planet gears 118
Needle bearing 119
Planet carrier 120
Adaptor 121
At least one cylinder 122
External splines 123
Piston 124
Lock nut 125
Shifter Fork 126

Bearing 127
Control unit 130
Third circumferential flange 131
Plurality of first gear teeth 133
Plurality of second gear teeth 135
Reservoir 137
Resilient member 140

We Claim:
1. A hub assembly (100) for an axle shaft (102) of a vehicle (200), the hub assembly (100)
comprising:
a housing (104);
a planetary gear set (106) disposed within the housing (104), wherein the planetary gear set (106) is concentrically mounted on the axle shaft (102);
a bypass hub (105) rotatably connected to the housing (104), the bypass hub (105) comprises:
a casing (107);
a gear (108) disposed within the casing (107) and positioned at one end of
the axle shaft (102);
a clutch (110) movably disposed within the casing (107) between the planetary gear set (106) and the gear (108), wherein the clutch (110) is configured to selectively engage and disengage with the planetary gear set (106) and the gear (108);
an actuator (112) disposed within the casing (107) proximate to the clutch (110), the actuator (112) is configured to displace the clutch (110) between a first position (FP) and a second position (SP); and
wherein the clutch (110) is configured to selectively engage with the
planetary gear set (106) in the first position (FP) and engage the gear (108) in the
second position (SP) for variable torque transmission.
2. The hub assembly (100) as claimed in claim 1, wherein the planetary gear set (106)
comprises:
a sun gear (114) rotatably coupled to the axle shaft (102);
a ring gear (116) comprising a plurality of planet gears (118) radially arranged
within the ring gear (116), wherein the plurality of planet gears (118) are meshed in
between the ring gear (116) and the sun gear (114) and connected to the housing (104); and
wherein the plurality of planet gears (118) are configured to actuate the
housing (104) to transmit torque from the axle shaft (102) to wheels of the vehicle
(200) connected to the hub assembly (100).

3. The hub assembly (100) as claimed in claim 1, wherein the planetary gear set (106) transmits a first predetermined torque (T1) from the axle shaft (102) to the wheels (202).
4. The hub assembly (100) as claimed in claim 3, wherein the gear (108) transmits a second predetermined torque (T2) less than the first predetermined torque (T1) from the axle shaft (102) to the wheels (202).
5. The hub assembly (100) as claimed in claim 2, wherein the clutch (110) is circumferentially defined with a plurality of first gear teeth (133) extending in an axial direction to selectively engage with the sun gear (114) and engage the gear (108) in the first position (FP) and the second position (SP).
6. The hub assembly (100) as claimed in claim 1, wherein the actuator (112) comprises:
at least one cylinder (122) disposed within the casing (107), the at least one cylinder (122) is in fluid communication with a reservoir containing pressurized air; a piston (124) slidable within the at least one cylinder (122), the piston (124) is defined with a shifter fork (126) at one end and the lever (126) is connected to the clutch (110) to linearly displace the clutch (110) within the casing (107); and
wherein the at least one cylinder (122) receives the pressurized air to actuate the piston (124) within the at least one cylinder (122) for displacement of the clutch (110).
7. The hub assembly (100) as claimed in claim 1, comprises a control unit (130) communicatively coupled with the actuator (112), wherein the control unit (130) is configured to selectively actuate the actuator (112) based on a plurality of parameters for torque transmission.
8. The hub assembly (100) as claimed in claim 7, wherein the plurality of parameters include speed of the vehicle, load on the vehicle, steepness of a road.
9. A bypass hub (105) for a hub assembly (100) mounted on an axle shaft (102) of a vehicle (200), the bypass hub (105) comprising:

a casing (107) connectable to the hub assembly (100), the hub assembly (100) comprises a housing (104) and a planetary gear set (106) disposed within the housing (104);
a gear (108) disposed within the casing (107) and positioned at one end of the axle shaft (102);
a clutch (110) movably disposed within the casing (107) between the planetary gear set (106) and the gear (108), wherein the clutch (110) is configured to selectively engage and disengage with the planetary gear set (106) and the gear (108);
an actuator (112) disposed within the casing (107) proximate to the clutch (110), the actuator (112) is configured to displace the clutch (110) between a first position (FP) and a second position (SP); and
wherein the clutch (110) is configured to selectively engage with the planetary gear
set (106) in the first position (FP) and engage the gear (108) in the second position (SP)
for variable torque transmission.
10. A method (400) of operation of the hub assembly (100) connected to an axle shaft (102) of the vehicle (200) for the variable torque transmission, the method (400) comprising:
determining, by a control unit (130) at least one first parameter (P1) of a plurality of parameters of the vehicle;
actuating the actuator (112), by the control unit (130), to displace a clutch (110) to a first position for a first predetermined torque transmission from the axle shaft (102) to wheels (202) of the vehicle (200), wherein the clutch (110) is configured to engage with a planetary gear set (106) in the first position (FP);
determining, by the control unit (130), at least one second parameter (P2);
de-actuating the actuator (112), by the control unit (130) to disengage the clutch (110) with the planetary gear set (106) to restrict torque transmission from the axle shaft (102) to the wheels (202);
determining, by the control unit (130), at least one third parameter (P3) and actuating the actuator (112) to displace the clutch (110) to a second position (SP) for a second predetermined torque transmission from the axle shaft (102) to the wheels (202), wherein the clutch (110) is configured to engage with a gear (108) in the second position (SP); and

determining, by the control unit (130), the at least one second parameter and de-actuating the actuator (112), by the control unit (130) to disengage the clutch (110) with the gear (108) to restrict torque transmission from the axle shaft (102) to the wheels (202).
11. The method (400) as claimed in claim 10, wherein the at least one first parameter and the at least one second parameter and the at least one third parameter of the plurality of parameters is selected from a speed of the vehicle, load on the vehicle, steepness of a road.