Claims:1. A steering assembly (112) for a motor vehicle, said steering assembly (112) comprising;
a steering means (106);
a head tube (201) of said vehicle (100) and a steering member (305 ) being co-axially disposed on said steering axis (XX’) of said vehicle;
an electric power steering system (301), said electric power steering system (301) being disposed between said steering means (106) and a steering member (305 );
said electric power steering system (301) being operatively and co-axially connected to said steering means (106) and said steering member (305) to assist a user while steering said vehicle.
2. The steering assembly (112) as claimed in claim 1, wherein said electric power steering system (301) includes an input shaft (302) and an output shaft (303), said input shaft (302) being detachably coupled to said steering means (106).
3. The steering assembly (112) as claimed in claim 2, wherein said output shaft (303) being detachably coupled to said steering member (305 ).
4. The steering assembly (112) as claimed in claim 1, wherein steering member (305 ) includes a bush (307) being configured to receive said output shaft (303) of said electric power steering system (301).
5. The steering assembly (112) as claimed in claim 1, wherein said head tube (201) includes a mounting flange (401), where said mounting flange (401) being configured to mount said electric power steering system (301) with attachment means.
6. The steering assembly (112) as claimed in claim 5, wherein said mounting flange (401) being attached to said head tube (201) of said vehicle (100).
7. The steering assembly (112) as claimed in claim 1, wherein said steering member (305 ) being connected to a front wheel (101) of said vehicle (100), where said steering member (305 ) being connected to said steering means (106) through electric power steering system (301) disposed between said steering means (106) and said steering member (305) .
8. The vehicle includes a three wheeled vehicle as claimed in any of the preceding claims.
9. A method of activating electric power steering system (301) in a three wheeled vehicle, said method comprising:
receiving a steering input for taking turn from one or more torque sensors, by a vehicle control processing unit;
determining as a first determination, whether vehicle is taking turn;
comparing said real time lateral acceleration value with a predetermined lateral acceleration value based on affirmative determination that vehicle is taking turn;
determining as a second determination whether said real time lateral acceleration value is more than said predetermined lateral acceleration value; and
activating the electric power steering system to suppress steering oscillations or steering torque input by steering in an opposite direction for stabilizing the lateral acceleration, based on affirmative determination that real time lateral acceleration value is more than said predetermined lateral acceleration value.
10. The method of activating electric steering unit as claimed in claim 9, wherein determining as a first determination, whether vehicle is taking turn; based on negative determination,
comparing said real time vehicle steering rate value with a predetermined vehicle steering rate value,
determining as a third determination whether said real time rate of steering angle value is more than said predetermine steering angle rate value;
activating said electric power steering system to suppress said steering oscillations based on based on affirmative determination of third determination.
11. The method of activating the electric steering unit as claimed in claim 10, wherein said vehicle steering rate includes wobble rate.
12. The method of activating the electric steering unit as claimed in claim 9, wherein determining said second determination, and based on positive determination,
retarding speed of said vehicle to be within safe predetermined speed or restrict an acceleration input of the vehicle to be within a safe speed.
13. The method of activating the electric steering unit as claimed in claim 10, wherein determining said third determination, and based on positive determination,
restricting said rate of steering angle value of said vehicle to be within a safe speed , Description:TECHNICAL FIELD
[0001] The present subject matter relates to a motor vehicle. More particularly, the present subject matter relates to a steering assembly for the motor vehicle.

BACKGROUND
[0002] In many countries of the world, a motor vehicle is a significant mode of public transportation. It is vastly used as a point to point mode of transport in rural and urban areas also referred to as autorickshaw. Generally, the motor vehicle has a driver compartment in a front portion and a passenger load compartment in a rear portion. In case of a passenger vehicle, the rear compartment comprises of a passenger seat. A driver operates the vehicle from the first compartment. A driver seat is provided in the front compartment so that the driver operates the vehicle in a sitting position. A suspension structure for three wheeled vehicle normally employs separate trailing arm with rear suspension system to support the body on the two rear wheel assemblies. Also, wheels are connected to a frame assembly by the suspension structure, with steerable front wheels controlled by the driver with a steering assembly of the vehicle.
[0003] The steering system of an automobile serves two main functions: firstly it allows the driver to make the vehicle follow a desired path or trajectory without requiring excessive physical effort and secondly, it assists the driver to judge the driving conditions by allowing some feedback. Hence, by the steering assembly the driver is able to control direction of movement of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The detailed description is described with reference to a passenger transport layout of a three wheeled vehicle along with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[0005] Fig.1 is a side view of a motor vehicle as per one embodiment of the present invention.
[0006] Fig. 1a is a rear view of a motor vehicle as per one embodiment of the present invention.
[0007] Fig.2 is a frame assembly, as per one embodiment of the present invention.
[0008] Fig.3 is an assembled view of steering assembly as per one embodiment of the present invention.
[0009] Fig. 3a is a perspective view of an EPS as per one embodiment of present invention.
[00010] Fig.3b is a sectional view of steering assembly is a side view of the vehicle with second metal sheet cover or cover having locking mechanism.
[00011] Fig. 4 is an exploded view of steering assembly as per one embodiment of the present invention.
[00012] Fig. 5 is a block diagram of steering assembly as per one embodiment of teh present invention.
[00013] Fig. 6 is a flowchart as per one embodiment of the present invention.
[00014] Fig. 6a is a flowchart as per one embodiment of the present invention.
[00015] Fig. 6b is a flowchart as per one embodiment of the present invention.

DETAILED DESCRIPTION
[00016] Steering assembly is defined as an assembly of components, linkages which allow any vehicle to follow desired course. The primary function of steering assembly is to allow the driver to guide the vehicle. The aim of steering assembly is to ensure that the wheels are pointing in desired directions. This particular aim is achieved by a series of linkages, rods, pivots and gears. One of fundamental concepts on which the steering assembly functions is that each wheel is steered with a ground contact pivot point formed by projecting the pivot axis on the ground to fall ahead of the wheel (referred to as castor angle effect), which tends to make the steering assembly self-centering towards the direction of travel arising out of self-balancing steering torque in the event of deviation from the straight line of motion.
[00017] The linkages connecting a steering member and the wheels usually conform to a variation, for example, in a vehicle like a four wheeled vehicle, when the vehicle takes a turn, an inner wheel actually travels a path of smaller radius than the outer wheel.
[00018] The steering assembly converts rotation of steering wheel/handlebar assembly into a swiveling movement of wheels. For example, in the four wheeled vehicles, the assembly allows a driver to use only light force to steer the heavy vehicle. The steering effort passes to the wheels through a system of pivoted joints. These are designed to allow the wheels to move up and down with the suspension without changing the steering angle. They also ensure that when cornering, the inner front wheel, which has to travel round a tighter curve than the outer one, becomes more sharply angled. The joints must be adjusted very precisely, and even a little looseness or play in them makes the steering dangerously sloppy and inaccurate.
[00019] Further, to avoid the sloppy or inaccurate steering assembly, different types of steering assembly are configured in the vehicle like four wheeled vehicle. The steering assembly includes a rack and pinion steering assembly, a recirculating ball steering assembly and a power steering assembly. The rack and pinion steering assembly includes a steering wheel. The steering wheel has a shaft attached to it and on another end of the shaft is a pinion. The pinion is positioned on top of a rack and moves when the steering wheel is moved. The end of the rack includes tie rod. The tie rods connect to a wheel hub of the vehicle, where the tie rod connected to the wheel hub causes wheel to turn.
[00020] The recirculating ball steering includes a worm gear and a sector gear. This steering assembly is configured in a heavy duty vehicle like trucks. The power steering assembly configures a hydraulic piston, where the hydraulic piston moves around depending on which fluid line brings high pressure fluid.
[00021] In arena of development of technology, additional assistance is provided to the steering assembly of the vehicle like four-wheeled through an EPS unit that is Electrical Power Steering system. This assists driver's steering operation by applying power output from an electric motor to a steering mechanism of a vehicle.
[00022] In Electrical Power Steering system, a motor is connected to a part of the steering system through a reduction gearbox. The motor can be operated to apply an assistance torque to the steering system which can help the driver to turn the wheel during normal driving. The motor can also be used to apply a torque of the same sense or of an opposite sense. The torque which is applied by the driver or equivalent to the torque passed back from the road and wheels of the vehicle to steering means in order to provide other forms of driver assistance during abnormal operating conditions, thereby providing stable steering assembly to the vehicle.
[00023] Thus, it is apparent from above paragraph that stable steering assembly plays a very important role in balancing the vehicle and providing smooth as well as effortless ride to the rider/driver. Also, stability of the steering assembly of the four wheeler vehicle where EPS and reduction gear mechanism is configured conventionally, are greater than the stability of steering assembly in any other vehicles like three wheeled vehicles. Unlike as four wheeled vehicles, the three wheeled vehicles include a front wheel and a pair of rear wheels. A steering means is attached to a steering member either directly or through a vibration damper. The steering means through steering member consumes entire amount of work done by driver/rider for steering the vehicle. When the vehicle is moving on a straight road with maximum speed and suddenly it meets with an obstacle on the road, it stimulates the wobble motion in the vehicle. When the vehicle is moving on a straight road with maximum speed and tries to change lane on the road simultaneously, there may be a chances that vehicle may skid off the intended path on the road or drag out of the lane, and / or leading to toppling of the vehicle, thereby, increasing safety risk for the drivers and occupants. Thus, there is a need of having stable steering system in the vehicle especially in the three wheeler vehicle.
[00024] In known arts, multiple ways has been proposed or disclosed to increase stability of the steering assembly. One of the ways disclosed is to increase mechanical trail of steering assembly in the three wheeled vehicle. However, since the vehicle is provided with compact layout having different essential components conventionally disposed, hence, there exists a constraint of having sufficient space for configuring steering assembly having increased mechanical trail, for providing stable steering assembly in the vehicle. Additionally, increasing trail increases the effort of steering for the rider which is undesirable. Therefore, there exists a challenge of achieving a compact layout of a vehicle while providing stable and low effort steering assembly, ensuring safety of the driver/rider while driving/riding the vehicle at various driving conditions.
[00025] In another known art, electrical power steering system is disclosed in a four wheeler vehicle for a stable steering assembly in the vehicle. The EPS works as an assisting mechanism in the four wheeler vehicle to provide stable steering assembly along with Ackermann steering mechanism, wherein, linkages in the steering assembly of a vehicle assist in turning the inner and outer wheels at safe and desired angles. While driving the four wheeled vehicle, cornering of the vehicle, or changing lane of the vehicle is easy as compared to the three wheeled vehicle, as the four wheeled vehicle includes four wheels, where inner wheel covers less radius of curvature and outer wheel covers more radius of curvature to provide the stable steering assembly in the vehicle along with EPS system and also reduces chances of the toppling of the vehicle. Whereas as discussed earlier, the configuration or layout of the three wheeler is different from the four wheeler vehicle. Hence, it does not provide the stable steering assembly in the vehicle, thus, increases chances of toppling of the vehicle.
[00026] Hence, there exists a challenge of designing a stable steering assembly for a three wheeled vehicle, which can ensure the safety to the user having motor vehicles without any major change in design and manufacturing set-up of the vehicle.
[00027] Therefore, there is a need to have an improved steering assembly in a three wheeled vehicle while maintaining the conventional compact layout of the vehicle. There is a need to have a solution for safe & stable steering assembly which assists the driver while cornering or changing lane on the road while overcoming all of the above problems and other problems of known art.
[00028] The present invention provides a solution to the above problems while meeting the requirements of minimum modifications in vehicle, at low cost with ease of accessibility etc.
[00029] With the above objectives in view, the present invention relates to the three wheeled motor vehicle and more particularly to the improved steering assembly in the motor vehicle which increases stability of the vehicle while riding/driving the vehicle.
[00030] As per one aspect of the present invention, a motor vehicle is provided with a frame structure. The frame structure of the motor vehicle includes a head tube, a main frame and a central frame. A floor board is supported on the central frame and extended to the rearward of the vehicle. The floorboard is further divided into the floor board of a front cabin and the floorboard of a rear cabin. The front cabin of the vehicle includes a driver seat assembly. The driver seat assembly includes a driver seat frame which is housed and attached with various attachment means, for example fasteners, on the top of the central frame and a pair of LH (left hand) side frame member and RH (right hand) side frame member. The rear cabin of the vehicle includes a passenger seat. The passenger seat is detachably attached to a metal sheet or a cover with various attachment means, for example fastener.
[00031] As per one aspect of the present invention, a pair of rear frame members extend upward from the left hand side tube and right hand side tube and further extends horizontally to the rearward of the vehicle. The pair of rear frame members includes a left frame member and a right frame member extending horizontally to the rearward of the vehicle. The left frame member and right frame member are connected by a plurality of laterally and longitudinally connecting bridges, ensuring rigid attachment of the frame members. A steering means is attached to a head tube of the frame assembly. (In another implementation a steering wheel assembly may be attached instead of a handle bar assembly. For simplicity, the invention is explained with the means of a handle bar configuration and can be any one steering means viz. a handle bar assembly or a steering wheel assembly.) A steering member is detachably attached to the head tube of the frame assembly in the vehicle and extended downwardly for connecting to wheels of the vehicle. An electrical power steering (EPS) system is disposed between the steering member and the steering means of the vehicle, where the steering means, the EPS system and the steering member is combinedly termed as a steering assembly for the three wheeled vehicles.
[00032] As per one aspect of the present invention, the EPS system includes an input shaft, an output shaft, a casing, a controller and a motor. The input shaft is attached to the steering means of the vehicle and the output shaft of the EPS system is attached to the steering member of the vehicle through various attachment means like steering bush. The input shaft receives torque through steering means, where the motor with the controller assists the load provided on the EPS system from the handlebar assembly and the required load is transferred to the steering member through the output shaft of the EPS system for rotating the wheel either in left direction or in right direction.
[00033] In the ensuing paragraphs, the exemplary aspects, the vehicle is a three wheeled vehicle are disclosed. However, it is contemplated that the concepts of the present invention may be applied to any vehicle having steering means that is handle bar assembly or steering wheel without defeating the spirit of the invention.
[00034] Further "front" and "rear", and "left" and "right" referred to in the ensuing description of the illustrated embodiment refer to front and rear, and left and right directions as seen in a state of being seated on a seat of the vehicle and looking forward. Furthermore, a longitudinal axis refers to a front to rear axis relative to the vehicle, while a lateral axis refers generally to a side to side, or left to right axis relative to the vehicle.
[00035] The present invention is now described briefly in connection with the rendered drawings. It should be noted that like elements are denoted by the same reference numerals throughout the description.
[00036] Fig. 1 & Fig 1a is a side & rear view of a motor vehicle (100) and Fig. 2 is a perspective view of a frame assembly of the motor vehicle in accordance with an embodiment of the present subject matter. For brevity, Fig 1, Fig 1a and Fig 2 shall be discussed together. In an embodiment, the frame structure of the motor vehicle includes three compartments. A front compartment including a head tube (201) that mounts a steering means (106) of the motor vehicle and the head tube (201) is capable of steering a front wheel (101), a main frame (206) that connects the head tube (201) and a central member (203), a driver seat assembly (104) that is housed on top of the central member (203) and a pair of LH side member (205) and a RH side member (202). The motor vehicle also includes a pair of rear wheels (102) and a front fender (103) disposed above the front wheel (101). CNG cylinder etc. is housed in a housing area (110) under the driver seat assembly (104). In one embodiment, the frame assembly further includes a middle compartment that includes a passenger seat assembly (108) comprising of a seat base bottom and a back rest, a passenger barrier (107) restricting entry/exit of the passengers into the three wheeled vehicle in one direction, one or more lateral connecting bridge (204) capable of mounting a driver back rest. Further, in one embodiment, the frame assembly also includes a rear compartment that houses the cabin assembly (109), and a power unit (111) disposed substantially in the rear side of motor vehicle (fig. 1a).
[00037] Further, as per one embodiment of the present invention, a pair of rear frame members (214) extends upward from the left hand side member (205) and right hand side member (202) and further extends horizontally to rearward of the vehicle (100). The pair of rear frame member (214) includes a left frame member (213) and a right frame member (212) extending horizontally to rearward of the vehicle. The left frame member (213) and right frame member (212) are connected by a plurality of longitudinally (210, 211) and laterally members (204, 208, 209) disposed as connecting bridges, ensuring rigid attachment of the frame assembly.
[00038] Fig. 3 is an assembled perspective view of steering means with EPS assembly in the vehicle and Fig 3a is a perspective view of the EPS system as per one embodiment of the present invention. As per one embodiment of the present invention, a steering member (305 ) is detachably coupled to the head tube (201) of the frame assembly in the vehicle and extended downwardly for connecting to the wheel (101) of the vehicle. The electrical power steering (EPS) system (301) is disposed co axially between the steering means (106) and steering member (305) through head tube (201) of the vehicle, where the steering means(106), the EPS system (301) and the steering member (305) combinedly is termed as a steering assembly (112) for the three wheeled vehicle. Further, as per one embodiment of the present invention, the EPS system (301) shown in Fig 3a includes an input shaft (302), an output shaft (303), a casing (304c to house the EPS system, a controller and a motor (304). The input shaft (302) is detachable coupled to the steering means(106) of the vehicle and the output shaft (303) of the EPS system is detachable coupled to the steering member (305 ) of the vehicle through various attachment means like steering bush (307) (as shown in fig. 3b). The input shaft receives torque through steering means, where the motor with the controller assists effort provided on the EPS system from the handlebar assembly and the required effort is transferred to the steering member through the output shaft of the EPS system for rotating the wheel either in left direction or in right direction.
[00039] Fig. 4 is an exploded view of a steering assembly as per one embodiment of the present invention. As per one embodiment of the present invention, the EPS system (301) including the input shaft (302), where the input shaft (302) is detachably attached to the steering assembly (106) of the vehicle. The EPS system (301) is detachably disposed between the steering assembly (106) and the steering member (305) through head tube (201) with various attachment means like mounting flange (401). The mounting flange (401) is integrally attached with head tube (201) of the frame assembly. The output shaft (303) of the EPS system (301) configured such that it channelizes through an opening present in the mounting flange to be detachably attached with the steering bush of the steering member (305) and swivels the wheel with respect to steering axis (XX’). The head tube (201) of said vehicle (100) and a steering member (305 ) are co-axially disposed on the steering axis (XX’) of the vehicle The steering member (305) detachably abuts with the head tube through various rotary support means like pair of bearings that is upper bearing (403) and lock nuts (402a, 402b) and a lower bearing (not labelled), ensuring rigid attachment of the steering member with the head tube (201) of the frame assembly.
[00040] Fig, 5 is a block diagram of a steering assembly as per one embodiment of the present invention. As per one embodiment of the present invention, the steering means (106) provides torque to the input shaft (302), which is sensed by a torque sensor (501). The torque sensor ( 501) provides the signal as input to a signal conditioning module (504). The torque sensor (501) measures effort being applied by the driver to steer the vehicle. The signal conditioning module (504 ) after conditioning the received signal, provides it to a controller unit (505). The controller unit (505) sends desires output to motor (304) and to a worm and worm wheel gear (502), where a rotary motion of the motor unit is converted to a linear motion. This linear motion of the worm (not shown) is channelize to the output shaft (303) through suitable known torque transfer mechanism into a rotary torque on the steering member (305 ) and finally to the wheel (101) through the steering member (305), providing assistance to the steering effort of the vehicle in opposite direction, when the vehicle is at maximum speed, or cornering etc, which reduces the probability of toppling of the vehicle specially three wheeled vehicle in different scenarios.
[00041] Fig. 6 is a flowchart for steering assembly as per one embodiment of the present invention. At S601, vehicle is started. In S602, sensors like speed sensor detects speed of the vehicle. In S603, a controller determines that whether the detected speed of the vehicle is less than the predetermined speed of the vehicle which is saved in the controller unit. In S604, if the controller finds out that the speed of the vehicle is less than the predetermined speed of the vehicle, the controller deactivates the power of the motor of EPS system and allows regular torque transfer from the steering means to the steering member in an uninterrupted manner. In S605, the controller further analyzes that whether vehicle is taking turn or not, from the signal received from the sensors. In S606, the controller determines that whether the vehicle is taking turn. In S608, if the controller finds out that the vehicle is taking a turn, the controller executes step S610 (as describe in fig. 6a). In S607, if the controller finds out that the vehicle is not taking turn, the controller executes step S611 (as describe in fig. 6b).
[00042] In S610, the controller analyzes value of lateral acceleration, received from one or more of an gyro and acceleration sensor (not shown) on the vehicle . In S612, the controller determines that whether the lateral acceleration value is greater or equal to a predetermined safe value stored in lookup table of the controller. In S613, if the controller determines that the lateral acceleration of the vehicle is more or equal to the predetermined safe limit value stored in the lookup table, it activates the motor of the EPS system to produce opposite force to suppress steering torque and thus, eliminating toppling of the vehicle. As per an additional embodiment, the controller may additionally be configured to apply brakes to retard the speed of the vehicle to be within safe predetermined speed or restrict the acceleration input of the vehicle to be within a safe speed. Further, if the controller determines that the lateral acceleration of the vehicle is lesser than the predetermined value stored in the lookup table, it continues to permit a 1:1 ratio torque transfer from the steering means (106) to the steering member (305) monitor and analyses the value of the lateral acceleration without any interruption on the torque applied for steering. For example, when the vehicle is at maximum speed and taking a turn on the road. The controller measures the lateral acceleration of the vehicle, if the lateral acceleration of the vehicle is more than or equal to predetermined value the controller activates the motor of the EPS system and thus that motor produces the oppression force to suppress the steering oscillation or steering motion and thus eliminating the toppling of the vehicle.
[00043] In S611, the controller analyzes steering rate or steering oscillation, which includes wobble rate of the vehicle. In S614, the controller determines whether the steering rate of the vehicle i.e., rate of change of steering angle is more than or equal predetermined value of the steering rate. In S615, if the steering rate of the vehicle is more than or equal predetermined value of the steering rate, it activates the motor of the EPS system to produce opposite force to suppress steering oscillation or rotation and thus, eliminating toppling of the vehicle and activating the motor assist functionality. As per an additional embodiment, the controller may additionally be configured to apply brakes to retard the speed of the vehicle to be within safe predetermined speed or restrict the steering rate input of the vehicle to be within a safe speed. Further, if the controller determines that the if the steering rate of the vehicle is less than predetermined value of the steering rate lookup table, it continues to permit a 1:1 ratio torque transfer from the steering means (106) to the steering member (305) and monitor the vehicle steering rate.
[00044] The invention helps in overcoming the problem of toppling of the vehicle especially three wheeled vehicle while maintaining the overall weight and compact layout of the vehicle and additionally in a cost effective manner.
[00045] Advantageously, the embodiments of the present invention, describes the potential modifications in the steering assembly of the vehicle.
[00046] Many other improvements and modifications may be incorporated herein without deviating from the scope of the invention.
List of reference symbol:
Figure 1:
100: Motor Vehicle
106: steering means
101: Front Wheel
104: Driver Seat Assembly
102: Rear Wheels
103: Front Fender
110: Power Storage Housing Area
108: Passenger Seat Assembly
108a: Seat base bottom
108b: Back Rest
107: Passenger Barrier.
109: Cabin Assembly
111: Internal Combustion Engine
Figure 2:
201: Head Tube
206: Main Tube
203: Central Tube
205: LH Side member
202: RH Side member
214: A pair of rear frame member
204, 208, 209, 210, 211: Connecting Bridges
212: Right Hand Rear Frame
213: Left Hand Rear Frame
Figure 3:
301: EPS System
305: Steering Member
112: Steering Assembly
Figure 3a:
302: Input Shaft
304c: Motor Casing
304: Motor
Figure 3b:
307: Steel Bush
Figure 4:
401: Flange
402a, 402; Locking Nuts
403: Upper Bearings
XX’: Steering Axis
Figure 5:
501: Torque Sensor
502: Worm and Worm Wheel gear
504: Signal Conditioning Unit
505: Controller Unit
507: Battery