Title of Invention

FRONT FORK OUTER TUBE OF MOTOR CYCLE AND A METHOD OF MANUFACTURE THE REOF

Abstract A method of manufacture of the front fork outer tube of a motorcycle comprising the steps of ball burnishing the tube; flaring the said tube by a flaring punch and die to a conical shape; and again flaring the tube with the said punch and die to its final shape, draw oil being applied to the punch and die during the flaring operation; and cleaning the draw oil accumulated on the tube, thereafter. ABSTRACT A method of manufacture of the front fork outer tube of a motorcycle comprising the steps of ball burnishing the tube; flaring the said tube by a flaring punch and die to a conical shape; and again flaring the tube with the said punch and die to its final shape, draw oil being applied to the punch and die during the flaring operation; and cleaning the draw oil accumulated on the tube, thereafter.
Full Text

This invention relates to the front fork outer tube of a motorcycle and a method of manufacture thereof.
Conventionally, the front fork outer tube of a motor cycle is manufactured by the extrusion method involving the stretching of the outer tube to the desired length and shape, in four stages, two operations carried out on each press. This method is of the cold working kind causing residual stresses within the tube and such stresses will have to be relieved to obtain defect free tubes by subjecting them to heat treatment.
The conventional method employed as aforesaid is cumbersome, apart from not being environment friendly.
Additionally, the entire conventional method from start to finish involves as many as nine stages and therefore has a high lead time e.g. of about 20 hours; high method cycle time e.g. of about 167 min.; more space occupation e.g. 133 sg. meters; high method cost e.g. about Rs.30 per vehicle; more walking distance e.g. about 195 meters; more inventory e.g. 3480 numbers; more number of stages e.g. about 9; Zn phosphate in effluent e.g. 300 gms/day; generation of phosphate containing waste water and sludge;

contamination of land and water.
This invention therefore proposes a front fork
outer tube of a motor cycle and a method of manufacture
«
thereof which eliminates or at least considerably minimises the above mentioned drawbacks.
The method, according to this invention, for the manufacture of the front fork outer tube of a motorcycle, comprises the steps of ball burnishing the tube; flaring the said tube by a flaring punch and die to a conical shape; and again flaring the tube with the said punch and die to its final shape, draw oil being applied to the punch and die during the flaring operation; and cleaning the draw oil accumulated on they tube, thereafter.
This invention will now be described with reference to the accompanying drawings wherein Fig.1 illustrates- the flow chart of the various stages of manufacture of the tube according to the known method
Fig.2 illustrates the different stages of the extrusion process according to the known method of manufacture of the tube
Fig.3 illustrates, by way of example, the flow chart of the two stages of manufacture of the tube according

to the method proposed herein
Fig.4 illustrates, by way of example, the steps of the flaring process in the manufacture of the tube according to the method proposed herein
Referring to Figs. 1 and 2 it will be seen that the known method of manufacture of the tube by extrusion involves nine stages of manufacture as explained below. Extrusion is a method of stretching the material from a given diameter and length to a smaller diameter and bigger length with lubrication of bonderising (phosphate coating). By way of example, the size of the raw material is 0D= 46.5, thickness 2.65 and length 215 mm. The steps involved in the conventional method are:
1. Buffing of inside dia for removing dirt and unevenness to finally give an improved finish.
2. Buffing of outside dia for removing dirt and unevenness to finally give an improved finish.
3. Cleaning the tube after polishing to keep the tube free from loose burr and grit particles.
4. Phosphate coating (bonderising) the tube which acts as a lubricant for further extrusion.
5. Extrusion, which takes place in four steps, to give the desired shape to the outer tube of the fork.

The four steps are as follow:
The end of the outer tube is made conical with an angle
of 12.5 degrees from the side.
T,he diameter at the other end is increased.
The length of the lower portion of the tube is
increased.
The length of the larger diameter of the tube is
increased.
6. The extruded tube is heat treated for stress
relieving.
7. Crack check for cracks that may have developed
during extrusion*
8. Descaling is carried out for removing scales formed during the stress relieving operation.
9. Oil quenching the tube after descaling to prevent rust.
Subsequently, the tube is machined and welded in the usual way.
In the proposed method (Figs. 3 and 4), the tube is subjected to flaring, that is, a method of enlarging (stretching) the tube from a given diameter and length to a bigger diameter with the desired length.
There are only two stages in the proposed method, cutting down the nine stages in the existing

method.
The first stage is flaring and the second is cleaning.
EXAMPLE
Details of flaring operation:
The flaring operation is done in a 63 T hydraulic press with three steps combined in one tool (a) ball burnishing (b) pre-flaring to conical shape (c) final flaring to bring it to final shape (Fig.4).
The raw material inside dia will be 34 mm tolerance -0.2. The tube wall thickness will be 2.5 mm tolerance +/- 0.1 and the length will be 300 +/- 1 mm respectively.
Step 1: Ball burnishing operation
The inner diameter 34 -0.2 is to be burnished to 34
+0.1 with a carbide ball to achieve consistency in tube
internal diameter. This is required for having optimum
clearance between tube ID and punch in further steps of
flaring.
Step 2: Pre-flaring:
One end of the tube is pre-flared to outer dia 45 from
39 and the end is conical with a taper of 10 - 12
degrees.

Jtep 3: Final flaring.
Phe pre-flared tube is final flared to achieve ID of 40.35 -0.05 height 233 +/- 0.75 and straight land dimension of 0.4 + 0.02 and minimum wall thickness of 2.0 mm in the flared area as shown in Fig.4.
In the flaring method draw oil will be used as the lubricant. The draw oil will be applied on the punch and die to flare (enlarge) the diameter. Cleaning is carried out next to remove the draw oil adhering to the tube. It is necessary to keep the tube surface oil-free to avoid collet slippage in subsequent machining process.
Thereafter the machining and welding operation is carried out in the usual way.
The advantages of the method proposed herein are: Cost saving will be,e.g. Rs.30/» per vehicle; process cycle time will be e.g. 1 min.; lead time will be e.g. 2.23 hours; less space occupation; walking distance will be e.g. 15 meters; productivity can be improved to e.g. 300% ; inventory can be reduced to e.g. 160 numbers; will be a good EHS friendly method; Zn phosphate in effluent can be eliminated.

The terms and expressions in this specification are of description and not of limitation, there being no intention to exclude any equivalent of the features illustrated and described, but it is understood that various other other ways of carrying out the method proposed herein are possible without departing from the scope and ambit of t-hic intronfi* —




We Claim:
1. A method of manufacture of the front fork outer tube of a motorcycle comprising the steps of ball burnishing the tube; flaring the said tube by a flaring punch and die to a conical shape; and again flaring the tube with the said punch and die to its final shape, draw oil being applied to the punch and die during the flaring operation; and cleaning the draw oil accumulated on the tube, thereafter.
2. A method of manufacture of the front fork
outer tube of a motorcycle substantially as herein
described and illustrated with reference to the
Example and the accompanying drawings.
3. A front fork outer tube of a motorcycle
whenever manufactured by a method as claimed in any one
of the preceding Claims.
Dated this the 10th March 2003




This invention relates to the front fork outer tube of a motorcycle and a method of manufacture thereof.
Conventionally, the front fork outer tube of a motor cycle is manufactured by the extrusion method involving the stretching of the outer tube to the desired length and shape, in four stages, two operations carried out on each press. This method is of the cold working kind causing residual stresses within the tube and such stresses will have to be relieved to obtain defect free tubes by subjecting them to heat treatment.
The conventional method employed as aforesaid is cumbersome, apart from not being environment friendly.
Additionally, the entire conventional method from start to finish involves as many as nine stages and therefore has a high lead time e.g. of about 20 hours; high method cycle time e.g. of about 167 min.; more space occupation e.g. 133 sq. meters; high method cost e.g. about Rs.30 per vehicle; more walking distance e.g. about 195 meters; more inventory e.g. 3480 numbers; more number of stages e.g. about 9; Zn phosphate in effluent e.g. 300 gms/day; generation of phosphate containing waste water and sludge;

contamination of land and water.
This invention therefore proposes a front fork outer tube of a motor cycle and a method of manufacture thereof which eliminates or at least considerably minimises the above mentioned drawbacks.
The method, according to this invention, for the manufacture of the front fork outer tube of a motorcycle, comprises the steps of ball burnishing the tube; flaring the said tube by a flaring punch and die to a conical shape; and again flaring the tube with the said punch and die to its final shape, draw oil being applied to the punch and die during the flaring operation; and cleaning the draw oil accumulated on the. tube, thereafter.
This invention will now be described with reference to the accompanying drawings wherein Fig.l illustrates- the flow chart of the various stages of manufacture of the tube according to the known method
Fig.2 illustrates the different stages of the extrusion process according to the known method of manufacture of the tube
Fig.3 illustrates, by way of example, the flow chart of the two stages of manufacture of the tube according

to the method proposed herein
Fig.4 illustrates, by way of example, the steps of the flaring process in the manufacture of the tube according to the method proposed herein
Referring to Figs. 1 and 2 it will be seen that the known method of manufacture of the tube by extrusion involves nine stages of manufacture as explained below. Extrusion is a method of stretching the material from a given diameter and length to a smaller diameter and bigger length with lubrication of bonderising (phosphate coating). By way of example, the size of the raw material is 0D= 46.5, thickness 2.65 and length 215 mm. The steps involved in the conventional method are:
1. Buffing of inside dia for removing dirt and unevenness to finally give an improved finish.
2. Buffing of outside dia for removing dirt and unevenness to finally give an improved finish.
3. Cleaning the tube after polishing to keep the tube free from loose burr and grit particles.
4. Phosphate coating (bonderising) the tube which acts as a lubricant for further extrusion.
5. Extrusion, which takes place in four steps, to give the desired shape to the outer tube of the fork.

The four steps are as follow:
The end of the outer tube is made conical with an angle
of 12.5 degrees from the side.
The diameter at the other end is increased.
The length of the lower portion of the tube is
increased.
The length of the larger diameter of the tube is
increased.
6. The extruded tube is heat treated for stress
relieving.
7. Crack check for cracks that may have developed
during extrusion.
8. Descaling is carried out for removing scales formed during the stress relieving operation.
9. Oil quenching the tube after descaling to prevent rust.
Subsequently, the tube is machined and welded in the usual way.
In the proposed method (Figs. 3 and 4), the tube is subjected to flaring, that is, a method of enlarging (stretching) the tube from a given diameter and length to a bigger diameter with the desired length.
There are only two stages in the proposed method, cutting down the nine stages in the existing

method.
The first stage is flaring and the second is cleaning.
EXAMPLE
Details of flaring operation:
The flaring operation is done in a 63 T hydraulic press with three steps combined in one tool (a) ball burnishing (b) pre-flaring to conical shape (c) final flaring to bring it to final shape (Fig.4).
The raw material inside dia will be 34 mm tolerance -0.2. The tube wall thickness will be 2.5 mm tolerance +/- 0.1 and the length will be 300 +/- 1 mm respectively.
Step 1: Ball burnishing operation
The inner diameter 34 -0.2 is to be burnished to 34
+0.1 with a carbide ball to achieve consistency in tube
internal diameter. This is required for having optimum
clearance between tube ID and punch in further steps of
flaring.
Step 2: Pre-flaring:
One end of the tube is pre-flared to outer dia 45 from
39 and the end is conical with a taper of 10 - 12
degrees.

Step 3: Pinal flaring.
The pre-flared tube is final flared to achieve ID of 40.35 -0.05 height 233 +/- 0.75 and straight land dimension of 0.4 + 0.02 and minimum wall thickness of 2.0 mm in the flared area as shown in Fig.4.
In the flaring method draw oil will be used as the lubricant. The draw oil will be applied on the punch and die to flare (enlarge) the diameter. Cleaning is carried out next to remove the draw oil adhering to the tube. It is necessary to keep the tube surface oil-free to avoid collet slippage in subsequent machining process.
Thereafter the machining and welding operation is carried out in the usual way.
The advantages of the method proposed herein are: Cost saving will be,e.g. Rs.30/- per vehicle; process cycle time will be e.g. 1 min.; lead time will be e.g. 2.23 hours; less space occupation; walking distance will be e.g. 15 meters; productivity can be improved to e.g. 300% ; inventory can be reduced to e.g. 160 numbers; will be a good EHS friendly method; Zn phosphate in effluent can be eliminated.

The terms and expressions in this specification are of description and not of limitation/ there being no intention to exclude any equivalent of 'the features illustrated and described, but it is understood that various other other ways of carrying out the method proposed herein are possible without departing from the scope and ambit of this invention.


We Claim:
1. A method of manufacture of the front fork outer tube of a motorcycle comprising the steps of ball burnishing the tube; flaring the said tube by a flaring punch and die to a conical shape; and again flaring the tube with the said punch and die to its final shape, draw oil being applied to the punch and die during the flaring operation; and cleaning the draw oil accumulated on the tube, thereafter.
2. A method of manufacture of the front fork outer tube of a motorcycle substantially as herein described and illustrated with reference to the Example and the accompanying drawings.
3. A front fork outer tube of a motorcycle whenever manufactured by a method as claimed in any one of the preceding Claims.
Dated this the 10-th March 2003


Documents:

0194-che-2003 claims duplicate.pdf

0194-che-2003 description (complete) duplicate.pdf

0194-che-2003 form-19.pdf

194-che-2003-abstract.pdf

194-che-2003-claims.pdf

194-che-2003-correspondnece-others.pdf

194-che-2003-correspondnece-po.pdf

194-che-2003-description(complete).pdf

194-che-2003-drawings.pdf

194-che-2003-form 1.pdf

194-che-2003-form 26.pdf

194-che-2003-other document.pdf


Patent Number 196308
Indian Patent Application Number 194/CHE/2003
PG Journal Number 20/2006
Publication Date 19-May-2006
Grant Date 20-Dec-2005
Date of Filing 10-Mar-2003
Name of Patentee M/S. TVS MOTOR COMPANY LIMITED
Applicant Address JAYALAKSHMI ESTAES, NO.8, HADDOWS ROAD, CHENNAI 600 006
Inventors:
# Inventor's Name Inventor's Address
1 PAROKKARAN ANTONY RAPPAI TVS MOTOR COMPANY LIMITED, JAYALAKSHMI ESTAES, NO.8, HADDOWS ROAD, CHENNAI 600 006
2 SUBRAMHANYA CHANDRA SHEKAR TVS MOTOR COMPANY LIMITED, JAYALAKSHMI ESTAES, NO.8, HADDOWS ROAD, CHENNAI 600 006
3 PALANIYAPPAN KANNAN TVS MOTOR COMPANY LIMITED, JAYALAKSHMI ESTAES, NO.8, HADDOWS ROAD, CHENNAI 600 006
PCT International Classification Number B62K21/02
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA