DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[See Section 10, Rule 13]

VEHICLE REAR SUSPENSION SYSTEM;

MAHINDRA & MAHINDRA LIMITED, A COMPANY REGISTERED UNDER THE INDIAN COMPANIES ACT, 1913, HAVING ADDRESS AT MAHINDRA RESEARCH VALLEY, MAHINDRA WORLD CITY, PLOT NO: 41/1, P.O. – ANJUR, CHENGALPATTU – 603004, DIST. – KANCHEEPURAM, TAMIL NADU, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle rear suspension system and more particularly to the rear multilink suspension system.
BACKGROUND OF THE INVENTION
The suspension system is the most crucial part of a vehicle which plays a significant role in providing a smoother ride to the occupants of the vehicle, and to increase the traction of the vehicle on road. With the developments in the technology, the multi-link suspension system was introduced having a vast capability in mitigating the problems of the suspension system.
Generally, the multi-link suspension system comprises links which function collectively so as to improve riding and handling quality of the vehicle extending to the off-road driving. The multi-link suspension system allows smooth and independent movement of the wheels over the large bumps and uneven road surfaces.
It has been observed that the conventional rear multi-link suspension system fails to achieve higher suspension travels, which consequently affects the off-road performance of the vehicle. Further, it has also been observed that the Ramp Travel Index (RTI) which is a measure of higher diagonal suspension articulation is not met with the conventional multilink rear suspension system.
It has also been observed that an excessive lateral shifting in suspension articulation is also a major problem with the conventional multi-link rear suspension system.
Therefore, there is a requirement to solve at least one of the aforementioned problems.
SUMMARY OF THE INVENTION
The present invention provides a vehicle rear suspension system connected between a rear axle and the vehicle chassis, the suspension system comprising: a pair of upper link attached between the rear axle and the vehicle chassis; a pair of lower link attached between the rear axle and the vehicle chassis; a pair of dampers mounted at the rear axle to absorb the shocks, the dampers are connected with the vehicle chassis; a pair of coil springs disposed between the rear axle and the vehicle chassis; the coil springs are mounted at the upper side of the rear axle and positioned in such a manner that the suspension system provides a higher suspension total travel ranging between 232-238 mm. The suspension system is having a ramp travel index ranging between 598-638 mm. The suspension system includes a panhard rod (4) mounted between the rear axle (7) and a chassis or the vehicle body. The suspension system includes an axle bump stop disposed at the right side of the rear axle.

In accordance with an embodiment of the present invention, the right side coil spring is positioned at a distance of 410.7 -414.7 mm from the centre of the differential assembly whereas the left side coil spring is positioned at a distance of 410.7 -414.7mm from the centre of differential assembly.

BRIEF DESCRIPTION OF THE DRAWINGS
Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 is a perspective view of a rear multi-link suspension system of a vehicle in accordance with an embodiment of the present invention.
DISCLOSURE OF THE INVENTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.
The present invention provides a technical solution to the problems associated with the conventional rear multi-link suspension system. The present invention discloses that the mounting the lower end of the coil spring at the support member of the wheel facilitates the conventional suspension system in achieving the higher suspension travel and decreases the lateral shifting in suspension articulation and improves the off-road performance of the vehicle.
In accordance with the present invention, in Figure 1, the rear multi-link suspension system (10) of a vehicle comprises an upper link (1) and a lower link (2). The links (1, 2) are hinged on either side of the vehicle at first end of the links (1, 2). The links (1, 2) are hinged about a point on chassis of the vehicle via bush. Second ends of the links (1, 2) are connected to a rear axle (7) and extend to a wheel hub of the vehicle. The multi-link suspension system (10) includes coil springs (3) mounted at the rear axle (7) of the vehicle. A pair of dampers (8) is also positioned on the rear axle (7) such that each damper (8) is placed at rear side of each wheel (9). The coil spring (3) functions as a link between the wheels (9) and the vehicle body.
The multi-link suspension system further includes a Panhard rod (4) mounted between the rear axle (7) at one end and the chassis at the other. A pair of stabilizer bar (5) is fixed on the rear axle (7) such that each stabilizer bar (5) is placed at rear side of each wheel (9). An axle bump stop (6) is placed at the rear right side of the vehicle.
In accordance with an embodiment of the present invention, the suspension system (10) comprises a pair of upper link (1) attached between the rear axle (7) and the vehicle chassis. A pair of lower link (2) is attached between the rear axle (7) and the vehicle chassis. A pair of dampers (8) is mounted at the rear axle (7) to absorb the shocks; the dampers (8) are connected with the vehicle chassis. A pair of coil springs (3) is disposed between the rear axle (7) and the vehicle chassis wherein the coil springs (3) are mounted at the upper side of the rear axle and positioned in such a manner that the suspension system provides a higher suspension total travel ranging between 232-238 mm. The suspension system includes a panhard rod (4) mounted between the rear axle (7) and a chassis or the vehicle body.

In accordance with an embodiment of the present invention, in operation, the coil springs (3) mounted on the rear axle (7) of the vehicle are compressed/ extend by the vertical movement of the wheels (9) and absorb the impact of the striking irregularities in the road surface keeping axles and the wheels (9) in contact with each other whereas the dampers (8) of the suspension system (10) dissipate the energy stored in the coil springs (3). The bump stop (6) is a compressible suspension component which is configured to prevent the metal to metal collision as the suspension undergoes extreme compression.
In accordance with the disclosure of the present invention, the mounting of the coil spring (3) at the rear axle (7) of the vehicle enables the multi-link suspension system to provide a higher suspension travel, better ramp travel index and decreased lateral shifting of the axle during suspension articulation. The suspension system (10) of the present invention provides an improved on road and off-road performance of the vehicle. The system (10) provides an improved ramp travel index for off-road travel of the vehicle. The system (10) reduces the lateral shifting in suspension articulation.

In accordance with a non-limiting embodiment of the present invention, the suspension system is having a ramp travel index ranging between 598-638 mm.

In accordance with a non-limiting embodiment of the present invention, the present invention provides that the right side coil spring and left side coil spring are positioned at a distance of 410.7 - 414.7 mm from the centre of the differential assembly.

In accordance with an embodiment of the present invention, the suspension system includes a pair of stabilizer bar fixed at the rear axle.
Many modifications may be made without departing from the basic spirit of the present invention. Accordingly, it will be appreciated by those skilled in the art that the invention may be practised other than has been specifically described herein.
,CLAIMS:WE CLAIM:
1. A vehicle rear suspension system connected between a rear axle and the vehicle chassis, the suspension system (10) comprising:
a pair of upper link (1) attached between the rear axle (7) and the vehicle chassis;
a pair of lower link (2) attached between the rear axle (7) and the vehicle chassis;
a pair of dampers (8) mounted at the rear axle (7) to absorb the shocks, the dampers (8) are connected with the vehicle chassis;
a pair of coil springs (3) disposed between the rear axle (7) and the vehicle chassis; the coil springs (8) are mounted at the upper side of the rear axle and positioned in such a manner that the suspension system provides a higher suspension total travel ranging between 232-238 mm.

2. The Vehicle rear suspension system as claimed in claim 1, wherein the suspension system is having a ramp travel index ranging between 598-638 mm.

3. The Vehicle rear suspension system as claimed in claim 1, wherein the right side coil spring is positioned at a distance of 410.7 -414.7 mm from the centre of the differential assembly.

4. The Vehicle rear suspension system as claimed in claim 1, wherein the left side coil springs is positioned at a distance of 410.7 -414.7mm from the centre of differential assembly.

5. The Vehicle rear suspension system as claimed in claim 1, wherein the suspension system includes a panhard rod (4) mounted between the rear axle (7) and a chassis or the vehicle body.

6. The Vehicle rear suspension system (10) as claimed in claim 1, wherein the suspension system includes a pair of stabilizer bar (5) fixed at the rear axle (7).

7. The Vehicle rear suspension system (10) as claimed in claim 1, wherein the suspension system includes an axle bump stop disposed at the right side of the rear axle.

8. The Vehicle rear suspension system as claimed in claim 1, wherein the suspension system reduces the lateral shifting in suspension articulation.
Dated this 27th day of February, 2020

For MAHINDRA & MAHINDRA LIMITED
By their Agent

GIRISH VIJAYANAND SHETH IN/PA- 1022
KRISHNA & SAURASTRI ASSOCIATES LLP