Title of Invention

"An Improved Process For Manufacturing Disc of Wheel Rims"

Abstract An improved process for manufacturing disc of wheel rims comprising: blanking of sheet material separately for improving productivity and safety, drawing of done shape, redesigned to accommodate the reduced size sheet blank, second drawing of said dome shape to an intermediate shape closer to the desired shape of the disc to improve the draw ratio during subsequent shape forming of the disc, reverse drawing of said intermediate shape to form the desired shape of the disc, trimming of spoke flanges and piercing of central hub in said disc, flanging said central hub and drawing said disc for improving productivity and safety, coining of said bolt holes in said disc, piercing of vent holes in the outer periphery of said disc, and coining of said vent holes to improve the endurance of said disc. Reference: Figure 1
Full Text This invention relates to an automotive steel wheel rim more particularly, to a process for manufacturing disc of wheel rims.
BACKGROUND
Wheel rims consists of two parts, namely, rim and disc. Rim is the part that supports tyre on it and disc is the part that is bolted to the brake drum of the vehicle. Both components are manufactured separately and welded together to make wheel rim.
The conventional process for manufacturing disc of wheel rims is in the following 6 stages:
• blanking of sheet material and drawing to form dome shape of the
disc,
• reverse drawing of said dome shape to form the desired shape of
the disc,
• trimming of spoke flanges and piercing of central hub & bolt holes
in the said disc,
• flanging said central hub and drawing the said disc to its final
shape,
• coining of said bolt holes, and
• piercing of vent holes in the outer periphery of said disc
In this conventional process, the drawbacks are:
• Sheet material if taken 3 mm thickness as input gets reduced lo
approx. 2.4 mm thickness (i.e. 15-20 % thinning) at the critical
radii due to severe draw ratio during shape forming from first stage
to second stage

• Processing of smaller size blank is not possible in the existing
process due to lesser blank holding area available during drawing
operation of dome shape.
• The productivity of the process is less due to combinations of
operations in blanking & drawing of sheet materials (stage one)
and trimming & bolt holes piercing (stage three)
• There is no safety in blanking & drawing and also trimming & bolt
holes piercing operations , because operator has to put his hand
inside the die/press to remove the disc component.
• Further, there is no coining of the vent holes which reduces the
endurance life of the disc
The objects and summary of the invention
The object of the instant invention is to take lesser input thickness and width of sheet material maintaining the endurance requirements of said wheel rim and thereby reducing the cost of wheel rims and increase the fuel efficiency of the vehicles due to reduction in overall weight.
The second object of the invention is to increase the productivity by blanking of sheet material separately and not in combination with drawing. Similarly, separating the trimming and bolt hole piercing operations will also increase productivity.
The third object of the invention is to provide safety in blanking and drawing and also during trimming and bolt holes piercing by introducing self unloading mechanism oi components in the new process design.
The fourth object of this invention is to improve the endurance life of the disc by coining of the vent holes.

To achieve the said objectives, this invention provides an improved process for manufacturing disc of wheel rims comprising:
blanking of sheet material separately for improving productivity and
safely.
drawing of dome shape , redesigned to accommodate the reduced si/e
sheet blank, drawing of said dome shape to an intermediate shape closer to the
desired shape of the disc to improve the draw ratio during subsequent
shape forming of the disc,
reverse drawing of said intermediate shape to form the desired shape of
the disc.
trimming of spoke flanges and piercing of central hub in said disc.
flanging said central hub and drawing said disc to its final shape,
piercing of boll holes separately in said disc for improving productivity
and safety,
coining of said bolt holes in said disc,
piercing of vent holes in the outer periphery of said disc, and
coining of said vent holes to improve the endurance of said disc.
The material used is a special grade high tensile steel sheet.
The thickness of said steel sheet varies from 2.5 mm - 5 mm and width of said
sheet varies from 300 to 400mm depending upon the type of vehicle.
The draw radio during shape forming improves from 2.0-2.3 in conventional sequence to 1.2 -1.5 in the improved sequence.

Brief description of the drawings
The invention will now be described with reference to the accompanying drawings.
Figure 1 shows the flow diagram of the conventional process for manufacturing disc for wheel rims.
Figure 2 shows the flow diagram of the improved process for manufacturing disc for wheel rims.
Figure 3 and table 1 shows the comparison of thickness observed in the cut section of the discs manufactured by conventional and improved process.
Detailed description of the drawings
Referring to the drawings the steps of the conventional process, as shown in figure 1, are listed below:
Blanking steel sheet material (1) to shape (2) and drawing to form dome shape (3) followed by reverse drawing the said dome shape (3) to form the desired shape of the disc (4). Trimming of flanges (5) and piercing of central hub (6) and boll holes (7) is carried out in said disc. Further, flanging said central hub (6) and drawing said disc to its final shape (8). Coining of said bolt holes (7), and piercing of vent holes (9) in the outer periphery of said final disc (8) is also carried out.
The drawbacks of the conventional process have already been explained under the heading 'background'.

The instant invention has improved upon the conventional process, which is shown in figure 2 of the drawings. The improved process is explained below:
Blanking of sheet material (10) into a sheet blank (11) separately for improving productivity. Then drawing of dome shape (12) from said sheet blank (II) followed by second drawing of said dome shape (12) to an intermediate shape (13) closer to the desired shape of said disc to improve the draw ratio during subsequent shape forming.
Further, reverse drawing of said intermediate shape (13) is carried out to form the desired shape of the disc (14). Afterwards, trimming of flanges (15) and piercing of central hub (16) in said disc (14) is carried out which is followed by flanging said central hub (16) and drawing said disc (14) to its final shape (17).
Further, piercing bolt holes (18) is carried out separately in said final shape disc (17) for safely reasons. Coining of said bolt holes (18) in said final disc (17) and piercing of vent holes (19) are also carried out in the outer periphery of said disc (17). Lastly, coining of said vent holes is done to improve the endurance of said disc (17).
Figure 3 with table 1 shows the comparison of thickness observed in the cut section of disc (17) manufactured by conventional and improved process. In this figure and table it may be seen that the thickness of the steel sheet has been taken as 3 mm. in both the processes. The result achieved is that the thinning at the critical radii has been improved from 15 ~ 20% in the conventional process to 5 ~ 7 % in the improved process.
Using these results the input thickness and blank size of the sheet material could be reduced thereby reducing the weight and the cost of the wheel rims and increase the fuel efficiency of the vehicle.



1. A process for manufacturing disc of wheel rims comprising:
- blanking of sheet material separately for improving productivity and safety;
- drawing of dome shape, redesigned to accommodate the reduced size sheet blank;
- second drawing of said dome shape to an intermediate shape closer to the desired
shape of the disc to improve the draw ratio during subsequent shape forming of the
disc;
- reverse drawing of said intermediate shape to form the desired shape of the disc;
- trimming of spoke flanges and piercing of central hub in said disc;
- flanging said central hub and drawing said disc to its final shape;
- piercing of bolt holes separately in said disc for improving productivity and safety;
- coining of said bolt holes in said disc;
- piercing of vent holes in the outer periphery of said disc; and
- coining of said vent holes to improve the endurance of said disc.
2. The process as claimed in claim 1 wherein the sheet material used is special grade high
tensile steel sheets.
3. The process as claimed in claim 1 wherein the thickness of said steel sheet varies from 2.5
mm - 5 mm and width of said sheet varies from 300-400 mm depending upon the type of
vehicle.
4. The process as claimed in claim 1 wherein the draw ratio during shape forming improves
from 2.0-2.3 in conventional sequence to 1.2-1.5 in the improved sequence.

Documents:

255-del-2002-255-del-2002-Correspondence Others-(04-01-2013).pdf

255-DEL-2002-Abstract-(11-05-2009).pdf

255-del-2002-abstract.pdf

255-DEL-2002-Claims-(11-05-2009).pdf

255-DEL-2002-Claims-(30-08-2013).pdf

255-del-2002-claims.pdf

255-del-2002-Correspondence-Others-(04-06-2013).pdf

255-DEL-2002-Correspondence-Others-(11-05-2009).pdf

255-DEL-2002-Correspondence-Others-(30-08-2013).pdf

255-del-2002-correspondence-others.pdf

255-del-2002-description (complete).pdf

255-DEL-2002-Drawings-(11-05-2009).pdf

255-del-2002-drawings.pdf

255-DEL-2002-Form-1-(11-05-2009).pdf

255-del-2002-form-1.pdf

255-del-2002-form-18.pdf

255-DEL-2002-Form-2-(11-05-2009).pdf

255-del-2002-form-2.pdf

255-del-2002-form-3.pdf

255-del-2002-GPA-(04-06-2013).pdf

255-del-2002-gpa.pdf


Patent Number 258809
Indian Patent Application Number 255/DEL/2002
PG Journal Number 07/2014
Publication Date 14-Feb-2014
Grant Date 07-Feb-2014
Date of Filing 19-Mar-2002
Name of Patentee STEEL STRIPS WHEELS LIMITED.
Applicant Address P.O. DAPPAR DERABASSI PUNJAB -140506 INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 SINGH SUKHBIR B-1608, SHASTRI NAGAR, DELHI-110 052 INDIA.
PCT International Classification Number B21D 53/30
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA