FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
A subframe assembly for vehicles
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Mr. Vijay Lodhi, Mr. Pawan Awthankar, Mr. Mandar Hajare &
Mr. Soheb Ahmed
All Indian national
of TATA MOTORS LIMITED an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in
which it is to be performed.

FIELD OF INVENTION
This invention relates in general to frame assemblies for vehicles and more particularly to a subframe assembly for vehicles for mounting suspension and steering system.
BACKGROUND OF THE INVENTION
A Subframe assembly is removable section of a vehicle frame that fastens under the bottom of the vehicle body. The subframe assembly is usually mounted at the bottom of a vehicle body at the front or the rear. For example in a front engine type vehicle, front suspension and steering systems are mounted on a subframe at the front side of the vehicle body, and in a rear engine type vehicle rear suspension and powertrain along with a differential gear unit are mounted on a subframe at the rear side of the vehicle body.
The primary requirement from the subframe assembly structure is to provide sufficient strength and stiffness. Strength of the subframe assembly is paramount the subframe is subjected to very large mechanical stresses. The force of the vehicle is transferred to the subframe assembly from the suspension system. The stiffness of the structure is required in order to not only have effective isolation of road induced vibrations but also to help in reducing the lateral compliance at wheel center, which helps is achieving better vehicle dynamics. Conventionally the subframe assembly is typically made from a pair of spaced side frame members having front and rear ends, a front cross frame member connected across the front ends of the side frame members, and a rear cross frame member extending between the rear ends of the side frame members. Connecting brackets are welded on this subframe assembly for suspension lower link assembly mountings, rack and pinion mountings etc. Other conventional designs of subframe assembly incorporate these mounting brackets in large sheet metal stampings thus not requiring long members and cross members. The individual components are usually metallic pieces which are generally stamped and then welded together to form the final assembly. Further requirement from subframe assemblies is that they should be dimensionally accurate in series production. This is evidently required from maintaining consistency of performance of suspension system.

OBJECTIVE OF THE INVENTION
The main object of this invention is to provide a subframe assembly for vehicles for mounting suspension and steering system.
Another object of this invention is to provide a subframe assembly for vehicle with high dimensional accuracies for suspension and steering mounting hardpoints as well as other attachment points in series production.
Yet another object of this invention is to provide a subframe assembly for vehicle with a means for attaching lower link assembly of suspension system with a stiffer joint, thereby reducing vibration and noise as well as helping in reducing lateral compliances.
Yet another object of the present invention is to provide a subframe assembly which has lesser number of parts and eliminates the need for additional brackets for suspension attachment locations.
Yet another object of the present invention is to provide a subframe assembly which reduces weld related distortions.
Yet another object of the present invention is to provide a subframe assembly which is simple in construction, cost effective and has less weight.
SUMMARY OF THE INVENTION
The embodiments herein provide a subframe assembly for vehicle for mounting suspension and steering system. The subframe assembly comprises a plurality of cross members, a pair of longitudinal members having a plurality of profile corresponding to end profile of said plurality of cross members for connecting said plurality of cross members between said pair of long members, a lower link assembly provided for mounting at least one end of said cross member with long member.

According to present invention, the plurality of profile is a cut portion provided in said pair of longitudinal members to accommodate cross members ends. The profile for connecting said long member with cross members is provided at bottom surface of said long members. The lower link assembly includes a bush with a bolt and nut for connecting said cross member with long member. The lower link assembly having a front bush and rear bush with a bolts and nuts is used for connecting two consecutive cross members towards one end. A.rack and pinion bracket is connected on said cross member for mounting suspension and steering system. A closing plate and reinforcement sleeve is provided at either ends of said pair of longitudinal member for mounting said subframe on vehicle body mounting point.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawings wherein the showings are for the purpose of illustration of the invention only, and not for the purpose of limiting the same,
FIG. 1 shows an isometric top view of a subframe assembly with suspension lower link assembly in accordance with this invention.
FIG. 2 shows an exploded isometric top view of a subframe assembly with suspension lower link assembly in accordance with this invention.
FIG. 3 shows an isometric bottom view of a subframe assembly in accordance with this invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting the same,

The embodiments herein provide a subframe assembly 1 for vehicle for mounting suspension and steering system. The subframe assembly comprises a plurality of cross members, a pair of longitudinal members having a plurality of profile 18 corresponding to end profile 19 of said plurality of cross members for connecting said plurality of cross members between said pair of long members, a lower link assembly provided for mounting atleast one end said cross member with long member.
According to present invention, the plurality of profile 18 is a cut portion provided in said pair of longitudinal members to accommodate cross members ends. The profile 18 for connecting said long member with cross members is provided at the bottom portion of said long members. The lower link assembly includes a bush with a bolt and nut for connecting said cross member with long member. The lower link assembly having a front bush and rear bush with a bolts and nuts is used for connecting two consecutive cross members towards one end. A rack and pinion bracket is connected on said cross member for mounting suspension and steering system. A closing plate and reinforcement sleeve is provided at either ends of said pair of longitudinal member for mounting said subframe on vehicle body mounting point.
Referring to figures 1 to 3 illustrates a pair of long members connected to a pair of cross members, according to present invention. The front subframe assembly 1 comprises of Left hand (LH) longitudinal member 2, right hand (RH) longitudinal member 3, front cross member 4, rear cross member 5 and rack and pinion bracket 8. The LH longitudinal member 2 and RH longitudinal member 3 having the cut profile 18 provided for accommodating front cross member 4 and rear cross member 5 ends. The profile 18 is provided such that the bush with nut and bolts is easily accessible from the bottom for service purpose. The ends of front cross member 4 have front bush assembly provision 16 for front bush 14 of lower link assembly 6,7 and the ends of rear cross member 5 have rear bush assembly provision 17 for rear bush 15 of lower link assembly 6, 7. The rack and pinion brackets 8 are welded to front cross member 4. The lower link assembly 6, 7 is assembled to the front subframe assembly 1 by bolting front bush 14 to the front bush

assembly provision 16 on front cross member 4 using bush assembly bolt 11 and nut 12 and by bolting rear bush 15 to the rear bush assembly provision 17 on rear cross member 5 using bush assembly bolt 11 and nut 12. The front subframe assembly 1 is mounted on vehicle body at body mounting points 13. At body mounting points 13 closing plate 9 and reinforcement sleeve 10 are provided at each ends of LH longitudinal member 2 and RH longitudinal member 3 respectively.
According to present invention, the suspension lower link attachments are directly provided on the front and rear cross members thus eliminating the requirement of welded brackets. This helps to improve both strength and stiffness of the suspension attachment hardpoint. Additionally, all the lateral loads of suspension are directly transferred to the lateral front and rear cross members. This further helps to achieve better strength and rigidity. This in turn means that the lateral compliances at wheel center are reduced thus helping vehicle handling performance as well as noise and vibration performance. Reduced number of parts helps to reduce welding length requirements which mean lesser weld related distortions and stronger subassembly. Welding reduction also helps to achieve better dimensional control during assembly resulting into consistent performance in series production. Lesser number of parts also translates into reduced complexities in manufacturing and assembly. All the vehicle body attachments are designed to have orientation in vertical direction providing ease of assembly in series production line as well as assembly/disassembly during service.
ADVANTAGES
• The subframe assembly according to present invention is provided for mounting of suspension and steering systems. The subframe assembly is provided for attaching lower link assembly of suspension system with a stiffer joint, thereby reducing vibration and noise as well as helping in reducing lateral compliances.

• The subframe assembly for a vehicle according to present invention is provided with high dimensional accuracies for suspension and steering mounting hardpoints as well as other attachment points in series production.
• The subframe assembly includes lesser number of parts and eliminates the need for additional brackets for suspension attachment locations.
• It reduces weld related distortions, simple in construction, cost effective and less weight.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

We Claim
1. A subframe assembly for vehicle, comprising;
a plurality of cross members;
a pair of longitudinal members having a plurality of profile corresponding to end profile of
said plurality of cross members for connecting said plurality of cross members between said
pair of long members;
a lower link assembly provided for mounting atleast one end of said cross member with long
member.
2. The subframe assembly according to claim 1, wherein said plurality of profile is a cut portion provided in said pair of longitudinal members to accommodate cross members ends.
3. The subframe assembly according to claim 1, wherein said profile for connecting said long member with cross members is provided at bottom surface of said long members.
4. The subframe assembly according to claim 1, wherein said lower link assembly having a bush with a bolt and nut for connecting said cross member with long member;
5. The subframe assembly according to claim 1, wherein said lower link assembly having a front bush and rear bush with a bolts and nuts for connecting two consecutive cross members towards one end.

6. The subframe assembly according to claim 1, wherein a rack and pinion bracket is provided on said cross member for mounting suspension and steering system.
7. The subframe assembly according to claim 1, wherein a closing plate and reinforcement sleeve is provided at either ends of said pair of longitudinal member for mounting said subframe on vehicle body mounting point.