Title of Invention

A METHOD OF ASSEMBLING VEHICLE BODY

Abstract

This invention relates to vehicle body and method of assembling vehicle body thereof. Vehicle body comprises of structural sub-assemblies of underbody, front end. A pillars LH and RH side. Body side LH/ RH, roof and tailgate. Said structural sub assemblies are manufactured by spot welding and then coated with Cathodic Electro deposition (CED) Primer for corrosion resistance, then said sub assemblies are joined together by using adhesive and mechanical fasteners. Said structural subassemblies after CED coating may be assembled at main plant itself or can be transferred to satellite plants and assembled there based on requirement. Complete assembled vehicle body is then subjected to the paint cycle to have paint, giving the desirable aesthetic appearance. Vehicle body assembling process in accordance with this invention is preferably by "Distributed Manufacturing Strategy" (DMS). As per DMS, at the main (mother) plant, structural sub-assemblies of underbody, front end, A pillar LH / RH, Body side LH/ RH, roof and tailgate are manufactured by spot welding and these subassemblies are then coated with Cathodic Electro deposition (CED) primer for corrosion resistance. These spot welded and CED primer coated structural subassemblies are then dispatched to various satellite plants and complete vehicle body is built at satellite plant by joining these structural sub-assemblies using adhesive and mechanical fasteners so called Hybrid Joinery. The complete assembled vehicle body is then subjected to the paint cycle to have paint, giving the _ desirable aesthetic appearance.

Full Text

FORM 2 THE PATENTS ACT 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION (See Section 10; rule 13) TITLE OF THE INVENTION Vehicle Body And Method Of Assembling Thereof 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 Asmita Sathaye and Swapnil Gosavi both Indian Nationals 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 Complete specification particularly describes the invention and the manner in which it is to be performed. FIELD OF THE INVENTION This invention relates to vehicles and more particularly it relates to modular vehicle body construction having structural sub-assemblies assembled together by using hybrid joinery. BACKGROUND OF INVENTION Vehicle manufacturing unit includes many stations like press shop, weld shop, paint shop, trim shop etc. in order to carry out various manufacturing activities. Passenger car vehicle body basically comprises of various sheet metal sub assemblies of underbody, front end, pillars, body side, roof, tailgate etc. In conventional method of vehicle manufacturing, the individual sub-assembly is manufactured by spot welding or by using mechanical fasteners and structural adhesives. All the said sub-assemblies are then joined together by spot welding to form complete vehicle body. To have the corrosion resistance, entire vehicle body is immersed in Cathodic Electro deposition (CED) primer bath, where it is coated with CED primer. After CED primer coating, vehicle body is subjected to the paint cycle where vehicle is painted for giving the desirable aesthetic appearance. All the other parts and assemblies along with the pre-assembled engine are then fitted on the trim line to form a complete vehicle. Drawbacks associated with conventional method are: 1) Based on the demand for the vehicle at other locations, it is required to be transported the fully built vehicles from manufacturing site therefore the transportation of fully built vehicle is very cumbersome. 2) Huge investment is required to set up a complete vehicle manufacturing plant comprising press shop, weld shop, paint shop and trim shop etc. at one location. 3) This method is not capable to cater the fluctuating demands of market efficiently. OBJECTS OF INVENTION The main object of this invention is to provide a vehicle body which is manufactured by joining corrosion resistance primer coated sheet metal structural sub-assemblies with the help of structural adhesive and mechanical fasteners. Another object of this invention is to provide a vehicle body which can be manufactured at various locations by assembling various structural sub-assemblies which are transported from the main location. Yet another object of this invention is to provide a vehicle body having uniform thickness of corrosion coating to have improved corrosion resistance. Yet another object of this invention is to provide a complete vehicle body which has uniformity in the paint shade and has better aesthetic. Yet another object of this invention is to provide a vehicle body with simple & cost effective manufacturing method. Yet another object of this invention is to provide a vehicle body with improved NVH performance. Yet another object of this invention is to manufacture customized vehicle body with respect to various features, colors, shades to satisfy customer requirements. STATEMENT OF INVENTION Vehicle body comprises of cathodic electro deposition coated structural subassemblies of underbody unit, front end unit, A pillar units, body side units, roof unit and tailgate unit wherein said front end unit is joined to said underbody unit, said A pillar units are joined to assembly of said underbody unit and said front end unit, said body side units are joined to the assembly of underbody unit, front end unit and A pillars units, said roof unit is joined to the assembly of underbody unit, front end unit, A pillar units and body side units, said tailgate unit is joined to the assembly of underbody unit, front end unit, A pillar units, body side units and roof unit, wherein said structural sub assemblies are joined together by using hybrid joinery and thereafter painted to have a desired colour. Vehicle body, wherein said hybrid joinery comprises of structural adhesive and mechanical fasteners. Vehicle body wherein said structural adhesive is acrylic based or polyurethane based or epoxy based. Vehicle body wherein said mechanical fasteners are self piercing rivets, clinching means, screws and bolt and nuts. Vehicle body wherein said structural sub-assemblies are manufactured by using spot welding. Vehicle body wherein said A pillar units and body side units are of LH side and RH side. Method of assembling vehicle body comprises of a. Manufacturing the structural subassemblies of underbody unit, front end unit, A pillar units, body side units, roof unit and tailgate unit by a spot welding technique or by a known method at mother plant; b. Coating Cathodic electro deposition primer on said structural subassemblies at mother plant; c. Assembling said structural subassemblies at satellite plants or mother plant itself by using hybrid joinery; d. Painting the complete assembled vehicle body to give desired aesthetic appearance. Method of assembling vehicle body wherein said assembly of structural sub assemblies comprises of a. Joining front end unit to the underbody unit; b. Joining A pillar units to the assembly obtained by step (a); c. Joining body side units to the assembly obtained by step (b); d. Joining roof unit to the assembly obtained by step (c); e. Joining tail gate unit to the assembly obtained by step (d). Method of assembling vehicle body wherein said joining by hybrid joinery comprises a. applying adhesive on the mating surfaces of said structural sub assemblies b. Attaching structural sub assemblies c. Fastening by using mechanical fasteners. BRIEF DESCRIPTION OF THIS INVENTION Vehicle body in accordance with this invention mainly comprises of structural subassemblies of underbody, front end, A pillars LH and RH side, Body side LH/ RH, roof and tailgate. Said structural sub assemblies are manufactured by spot welding and then coated with Cathodic Electro deposition (CED) Primer for corrosion resistance, then said sub assemblies are joined together by using adhesive and mechanical fasteners. Said structural subassemblies after CED coating may be assembled at main plant itself or can be transferred to satellite plants and assembled there based on requirement. Complete assembled vehicle body is then subjected to the paint cycle to have paint, giving the desirable aesthetic appearance. Vehicle body manufacturing process in accordance with this invention is preferably by "Distributed Manufacturing Strategy" (DMS). As per DMS, at the main (mother) plant, structural sub-assemblies of underbody, front end, A pillar LH / RH, Body side LH/ RH, roof and tailgate are manufactured by spot welding and these sub-assemblies are then coated with Cathodic Electro deposition (CED) primer for corrosion resistance. These spot welded and CED primer coated structural sub-assemblies are then dispatched to various satellite plants and complete vehicle body is built at satellite plant by joining these structural subassemblies using adhesive and mechanical fasteners so called Hybrid Joinery. The complete assembled vehicle body is then subjected to the paint cycle to have paint, giving the desirable aesthetic appearance. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 shows joinery used for joining various structural sub-assemblies of vehicle body in accordance with this invention. Fig. 2 shows a perspective view of the structural sub assembly of "Underbody" of the vehicle body construction. Fig. 3 shows a perspective view of the structural sub assembly of "front end" of the vehicle body construction. Fig. 4 shows a perspective view of the structural sub assembly of "A pillar" of the vehicle body construction. Fig. 5 shows a perspective view of the structural sub assembly of "Body Side LH/RH" of the vehicle body construction. Fig. 6 shows a perspective view of the structural sub assembly of "Roof of the vehicle body construction. Fig. 7 shows a perspective view of the structural sub assembly of "Tailgate" of the vehicle body construction. Fig. 8 shows exploded view of the vehicle body in accordance with this invention. Fig. 9 shows sequence of assembly method used in the manufacturing of the vehicle body in accordance with this invention. DETAILED DESCRIPTION OF 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, Referring to figs 1 to 7 wherein vehicle body in accordance with this invention mainly comprises of structural sub-assemblies of underbody (a), front end (b), A pillars LH and RH side (c), Body side LH/ RH (d, d'), roof (e)and tailgate (f). Said structural sub assemblies are manufactured by spot welding technique and then coated with Cathodic Electro deposition (CED) primer for corrosion resistance, then said sub assemblies are joined together by using adhesive and mechanical fasteners so called hybrid joinery (g). Said structural subassemblies after CED coating may be assembled at main plant itself or can be transferred to satellite plants and assembled there based on requirement, and the complete assembled vehicle body is then subjected to the paint cycle to have paint giving the desirable aesthetic appearance. Hybrid joinery (g) used in the vehicle body manufacturing in accordance with this invention as shown in fig. 1 consists of joining of two sheet metal panels (A, B) which are coated with corrosion resistance coating i.e Cathodic Electro deposition primer (C) by using the structural adhesive (D) and mechanical fastener (E). In order to have optimized strength of the said joinery following parameters were selected. a) CED primer (C) optimization Based on various test results, parameters for Cathodic Electro Deposition (CED) primer giving maximum joint strength between CED primer (C) and sheet metal substrate (A,B) was selected. All the said structural sub-assemblies were subjected to this parameters to have maximum joint strength. b) Structural adhesive (D) We have to select the structural adhesive (D) which is able to withstand final painting cycle & meeting the vehicle performance. c) Mechanical joinery (E) In addition to structural adhesive (D), to enhance the strength of joinery and for holding said structural sub-assemblies at geometric holding points, mechanical fasteners (E) like Clinching means, Self Piercing Rivets (SPR), nut & bolts, screws etc. were selected. d) Pitch of the joinery: From manufacturing considerations and based on the various tests results pitch of application of the mechanical joinery (E) for making the vehicle is finalized. Structural sub-assembly underbody (a) as referred in Fig. 2 comprises of longitudinal members RH/ LH (10), assembly cross member (12) , assembly front floor (14), assembly central tunnel (16), assembly rear floor (18), assembly front sill LH/ RH (20), assembly rear sill LH/ RH (22). Two longitudinal members LH / RH (10) are placed parallel and cross members (12) are kept in the perpendicular direction joining two longitudinal members (10) to each other by spot welding. Centre tunnel (16) is then placed and joined to cross numbers (12) by spot welding. Assembly front floor (14) is then placed & joined to longitudinal members LH/RH (10), cross members (12) and central tunnel (16) by spot welding. Assembly rear floor (18) is then welded and assembled on it. Assembly front sill LH/RH (20) is then welded on LH & RH sides of the front floor (14). Assembly Rear floor sill LH/RH (22) is then assembled & welded. All the assemblies are welded by conversional spot welding. Structural sub-assembly Front End (b) as referred in Fig 3 comprises of Assembly Fire wall (30), Assembly wheel arch LH/RH (32) & Assembly Leaf Screen (34). Assembly Firewall (30) is placed between two Assembly wheel arch LH/RH (32) & then spot welded. Assembly leaf screen (34) is then placed and spot welded. Structural sub-assembly A Pillar LH/RH (c) as referred in Fig 4 comprises of A Pillar (40) & Assembly shotgun (42). Assembly shotgun (42) is joined on the A pillar (40) through spot welding. Structural sub-assembly Body Side LH/RH (d & d') as referred in Fig 5 comprises of Body side outer panel (50), Assembly B pillar (52) Assembly Cantral (54), & Rear Quarter upper panel (56). First Assembly Cant rail (54) is joined to Body side outer panel (50). Then Assembly B pillar (52) is assembled on it. Then Rear quarter Upper panel (56) is assembled. All the assembling is by spot welding. Structural sub-assembly Roof (e) as referred in Fig 6 comprises of Panel Roof (60), Panel roof bow front (62) & panel roof bow Rear (64). Panel roof bow front (62) & panel roof bow rear (64) are paced parallel to each other. Panel roof (60) is placed on them. Panel roof bow front (62) & panel roof bow rear (64) are joined on the panel roof (60) by spot welding. The figure 9 gives details about various steps involved in the manufacturing of the vehicle body. There are five steps involved in the manufacturing. Step I : Joining of sub-assembly Underbody (a) to the sub-assembly front end (b). Step II : Joining of sub-assembly A pillar (c) to the assembly of stage I i.e assembly of sub-assembly underbody (a) and sub-assembly front end (b). Step III : Joining of sub-assembly Body side LH/RH (d and d') to the assembly of stage II i.e assembly of sub-assembly Underbody (a), sub-assembly Front end (b) and sub-assembly A pillar (c). Step IV: Joining of sub-assembly Roof (e) to the assembly of stage III i.e assembly of sub-assembly Underbody (a), sub-assembly Front end (b), sub-assembly A pillar (c) & sub-assembly Body side LH/RH (d and d'). Step V: Joining of sub-assembly Tailgate (f) to the assembly of stage IV i.e assembly of sub-assembly Underbody (a), sub-assembly Front end (b), sub-assembly A pillar (c), sub-assembly Body side LH/RH (d and d') & sub-assembly Roof (e). As per the stage I, sub-assembly "Front end" (b) is assembled on the sub-assembly "underbody" (a). The details of sub-assembly "underbody" (a) is shown in Fig 2 & the details of sub-assembly "Front end" (b) is shown in fig 3. The sub-assemblies are joined as per joinery (g) described in Fig 1. After application of the adhesive in between gaps of two assemblies, it is ensured that application of all the mechanical fasteners is in such away that they can be applied with ease & adhesive is squeezed out properly after its application. All the mechanical joinery is applied at the predefined pitch. As per stage II, sub-assembly " A pillar " (c) is assembled on the assembly of Stage I. i.e on the sub-assembly of "underbody" (a) and sub-assembly of "front end" (b). The details of sub-assembly " A pillar" (c) is as per Fig 4. The sub-assembly "A pillar" (c) is joined as per joinery (g) described in Fig 1. After application of the adhesive in between gaps of two assemblies, it is ensured that application of all the mechanical fasteners is in such away that they can be applied with ease & adhesive is squeezed out properly after its application. All the mechanical joinery is applied at the pre-defined pitch. As per the stage III, sub-assembly "Body side LH/RH" ( d and d') are assembled on the assembly made in stage II i.e on the assembly of sub-assembly "Underbody" (a), sub-assembly "front end" (b) , & sub-assembly "A pillar" (c) . The details of sub-assembly "Body side LH/RH"(d and d') is as per fig 5. The sub-assembly "Body side LH/RH" (d and d') is joined as per joinery (g) described in Fig 1. After application of the adhesive in between gaps of two assemblies, it is ensured that application of all the mechanical fasteners is in such away that they can be applied with ease & adhesive is squeezed out properly after its application. All the mechanical joinery is applied at the pre-defined pitch. As per the stage IV, a sub-assembly " Roof (e) is assembled on the assembly made in stage III i.e on the assembly of sub-assembly "underbody" (a), sub-assembly "Front End" (b), sub-assembly "A pillar" (c) & sub-assembly "Body side LH/RH" (d). The details of sub-assembly "Roof" (e) is shown in the fig 6. The sub-assembly "Roof (e) is joined as per joinery (g) described in Fig 1. After application of the adhesive in between gaps of two assemblies, it is ensured that application of all the mechanical fasteners is in such away that they can be applied with ease & adhesive is squeezed out properly after its application. All the mechanical joinery is applied at the pre-defined pitch. As per the stage V, sub-assembly " Tailgate" (f) is assembled on the assembly made in stage IV i.e on the assembly of sub-assembly "Underbody" (a), subassembly "Front end" (b), sub-assembly "A pillar" (c) , sub-assembly "Body side LH/RK (d and d') & sub-assembly "Roof (e). The details of sub-assembly "Tailgate " (f) is shown in the fig 7. The sub-assembly "Tailgate" (f) is joined as per joinery (g) described in Fig 1. After application of the adhesive in between gaps of two assemblies, it is ensured that application of all the mechanical fasteners is in such away that they can be applied with ease & adhesive is squeezed out properly after its application. All the mechanical joinery is applied at the pre-defined pitch. 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. Vehicle body comprises of cathodic electro deposition coated structural subassemblies of underbody unit, front end unit, A pillar units, body side units, roof unit and tailgate unit wherein said front end unit is joined to said underbody unit, said A pillar units are joined to assembly of said underbody unit and said front end unit, said body side units are joined to the assembly of underbody unit, front end unit and A pillars units, said roof unit is joined to the assembly of underbody unit, front end unit, A pillar units and body side units, said tailgate unit is joined to the assembly of underbody unit , front end unit, A pillar units, body side units and roof unit, wherein said structural sub assemblies are joined together by using hybrid joinery and thereafter painted to have a desired colour. 2. Vehicle body as claimed in claim 1 wherein said hybrid joinery comprises of structural adhesive and mechanical fasteners. 3. Vehicle body as claimed in claim 1 and 2 wherein said structural adhesive is acrylic based or polyurethane based or epoxy based. 4. Vehicle body as claimed in claim 1 and 2 wherein said mechanical fasteners are self piercing rivets, clinching means, screws and bolt and nuts. 5. Vehicle body as claimed in claims 1 to 4 wherein said structural subassemblies are manufactured by using spot welding. 6. Vehicle body as claimed in claims 1 to 5 wherein said A pillar units and body side units are of LH side and RH side. 7. Method of assembling vehicle body as claimed in claims 1 to 6 comprises of a. Manufacturing the structural subassemblies of underbody unit, front end unit, A pillar units, body side units, roof unit and tailgate unit by a spot welding technique or by a known method at mother plant; b. Coating Cathodic electro deposition primer on said structural subassemblies at mother plant; c. Assembling said structural subassemblies at satellite plants or mother plant itself by using hybrid joinery; d. Painting the complete assembled vehicle body to give desired aesthetic appearance. 8. Method of assembling vehicle body as claimed in claim 7 wherein said assembly of structural sub assemblies comprises of a. Joining front end unit to the underbody unit; b. Joining A pillar units to the assembly obtained by step (a); c. Joining body side units to the assembly obtained by step (b); d. Joining roof unit to the assembly obtained by step (c); e. Joining tail gate unit to the assembly obtained by step (d). 9. Method of assembling vehicle body as claimed in claims 7 and 8 wherein said joining by hybrid joinery comprises a. applying adhesive on the mating surfaces of said structural sub assemblies b. Attaching structural sub assemblies c. Fastening by using mechanical fasteners. 10. Vehicle body and method of assembling vehicle body substantially as herein described with reference to accompanying drawings. ABSTRACT Vehicle Body And Method Of Assembling Thereof This invention relates to vehicle body and method of assembling vehicle body thereof. Vehicle body comprises of structural sub-assemblies of underbody, front end. A pillars LH and RH side. Body side LH/ RH, roof and tailgate. Said structural sub assemblies are manufactured by spot welding and then coated with Cathodic Electro deposition (CED) Primer for corrosion resistance, then said sub assemblies are joined together by using adhesive and mechanical fasteners. Said structural subassemblies after CED coating may be assembled at main plant itself or can be transferred to satellite plants and assembled there based on requirement. Complete assembled vehicle body is then subjected to the paint cycle to have paint, giving the desirable aesthetic appearance. Vehicle body assembling process in accordance with this invention is preferably by "Distributed Manufacturing Strategy" (DMS). As per DMS, at the main (mother) plant, structural sub-assemblies of underbody, front end, A pillar LH / RH, Body side LH/ RH, roof and tailgate are manufactured by spot welding and these subassemblies are then coated with Cathodic Electro deposition (CED) primer for corrosion resistance. These spot welded and CED primer coated structural subassemblies are then dispatched to various satellite plants and complete vehicle body is built at satellite plant by joining these structural sub-assemblies using adhesive and mechanical fasteners so called Hybrid Joinery. The complete assembled vehicle body is then subjected to the paint cycle to have paint, giving the _ desirable aesthetic appearance.

Documents:

2176-MUM-2007-ABSTRACT(17-10-2013).pdf

2176-MUM-2007-ABSTRACT(18-1-2012).pdf

2176-MUM-2007-ABSTRACT(6-9-2013).pdf

2176-mum-2007-abstract.doc

2176-mum-2007-abstract.pdf

2176-MUM-2007-CLAIMS(AMENDED)-(17-10-2013).pdf

2176-MUM-2007-CLAIMS(AMENDED)-(18-1-2012).pdf

2176-MUM-2007-CLAIMS(AMENDED)-(6-9-2013).pdf

2176-mum-2007-claims.doc

2176-mum-2007-claims.pdf

2176-MUM-2007-CORRESPONDENCE(25-7-2008).pdf

2176-mum-2007-correspondence(28-11-2007).pdf

2176-mum-2007-correspondence-received.pdf

2176-mum-2007-description (complete).pdf

2176-MUM-2007-DRAWING(17-10-2013).pdf

2176-MUM-2007-DRAWING(18-1-2012).pdf

2176-MUM-2007-DRAWING(6-9-2013).pdf

2176-mum-2007-drawings.pdf

2176-MUM-2007-FORM 1(6-9-2013).pdf

2176-MUM-2007-FORM 13(18-1-2012).pdf

2176-MUM-2007-FORM 13(6-9-2013).pdf

2176-mum-2007-form 18(28-11-2007).pdf

2176-MUM-2007-FORM 2(TITLE PAGE)-(17-10-2013).pdf

2176-MUM-2007-FORM 2(TITLE PAGE)-(6-9-2013).pdf

2176-MUM-2007-FORM 3(25-7-2008).pdf

2176-mum-2007-form 8(28-11-2007).pdf

2176-mum-2007-form 9(28-11-2007).pdf

2176-MUM-2007-FORM PCT-IB-373(28-7-2011).pdf

2176-MUM-2007-FORM PCT-ISA-237(28-7-2011).pdf

2176-mum-2007-form-1.pdf

2176-mum-2007-form-2.doc

2176-mum-2007-form-2.pdf

2176-mum-2007-form-26.pdf

2176-mum-2007-form-3.pdf

2176-MUM-2007-GENERAL POWER OF ATTORNEY(18-1-2012).pdf

2176-MUM-2007-MARKED COPY(17-10-2013).pdf

2176-MUM-2007-MARKED COPY(18-1-2012).pdf

2176-MUM-2007-REPLY TO EXAMINATION REPORT(18-1-2012).pdf

2176-MUM-2007-REPLY TO EXAMINATION REPORT(28-7-2011).pdf

2176-MUM-2007-REPLY TO HEARING(17-10-2013).pdf

2176-MUM-2007-REPLY TO HEARING(6-9-2013).pdf

2176-MUM-2007-SPECIFICATION(AMENDED)-(17-10-2013).pdf

2176-MUM-2007-SPECIFICATION(AMENDED)-(18-1-2012).pdf

2176-MUM-2007-SPECIFICATION(AMENDED)-(6-9-2013).pdf

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