|Title of Invention||
A METHOD OF MANUUFACTURE OF METALLIC BRAKE HOSE END FOR AUTOMOBILE AND HOSE END ASSEMBLY PREPARED BY SUCH METHOD
|Abstract||Hose ends were made of two parts, which are to be joined together by a suitable process, which assures 100% reliability of the joint both on strength and leakage. Being a brake part, the right type of joining process ensures safety In this invention stored energy capacitor discharge type welding process was proven to be the most reliable process. By suitable design of the components, the heating energy is concentrated on the weld zone only. The control system permits only the right amount of energy. Consequent to this, there will be no distortion or discolourisation of the parts and also the required weld strength is achieved. The part is thus produced by an environment friendly process and reduced waste. This is as compared to other known processes like brazing or full machining of the same part.|
This invention relates to a new method of welding of hose ends and hose end assembly produced by such method.
At present hose ends are manufactured through brazing process. TTie components are passed through a continuous Mesh Belt Conveyor Furnace for the Melting of copper rings placed in the assembly, the furnace temperature being set at 1150 degrees Centigrade. The furnace is/, .operated in a controlled atmosphere of cracked ammonia. The brazing process thus consists of melting of copper at a high temperature in the presence of a fluxing type protective atmosphere.
The brazing process has certain disadvantages such as copper rings missing during the process, hole blockage, female thread tightness, peeling of metal plating, operator fatigue and atmospheric pollution.
The aim of the invention is to avoid the above drawbacks by adopting a better and improved method of manufacture.
According to the invention, there is provided a method for manufacture of metallic brake hose end fittings comprising a selected welding of specially machined skirt and body wherein the welding is done by means of electrical discharge resistance welding in which electrical energy is produced from a capacitor discharge type equipment.
The invention eliminates humar error, thread shrinkage, scaling on components, and hole blockage, it is environment friendly, reduces operator fatigue, can be performed in a room and the product presents an improved aesthetic appearance. Other advantages are 1) Energy is concentrated on the weld zone 2) Voltage fluctuations have no influences on weld quality 3) Permits the right amount of energy required 4) Heating is localized in the weld zone and 5) No distortion of components.
The invention is reliable to meet higher volumes of production and does not require any special steel or iron and is quite economical.
The invention also includes hose end assembly manufactured by the method.
The invention will now be described by way of example with reference to the accompanying drawings: -
Figure 1 represents a section of SKIRT and Figure 2 is the plan view of the skirt, showing the diameter.
Figure 3 illustrates a cross section view of the HOSE END BODY of TYPE A.
Figure 4 illustrates the elevation view of the HOSE END BODY of TYPE A.
Figure 5 illustrates the aoss section view of the HOSE END BODY of TYPE B.
Figure 6 illustrates the elevation view of the HOSE END BODY of TYPE B.
Figure 7 illustrates the plan view of the HOSE END BODY of TYPE B.
Figure 8 shows the position of the SKIRT and the HOSE END BODY of TYPE A during Welding.
Figure 9 shows the position of the SKIRT and the HOSE END BODY of TYPE B during Welding.
Figure 10 shows the position of the SKIRT and the HOSE END BODY of TYPE A after Welding.
Figure 11 shows the position of the SKIRT and the HOSE END BODY of TYPE B after Welding.
The hose end fittings, presently being described are made by joining two metallic parts. The two parts are Joined through the process of Pulse Welding.
The two parts are called the 'SKIRT and the 'BODY'.
The skirt (labelled 1 in reference drawings enclosed) is machined out of a steel tube with the material specification of CEW1 TO IS: 3074.
The material available in the 80 degrees included angle area is for welding puposes. This is called the weld preparation area.
The second part is called the body of the hose end. The body is machined out of mild steel material. The shape of the part will vary from one to another, depending on the vehicle application.
Two such parts, which are representative are illustrated in FIGURES 3,4,5,6 & 7. The first type is labelled 2 and the second as 3.
The above drawings illustrate the parts, as prepared prior to the welding process. After preparation of the components, both the skirt (1) and the body are degreased to remove the traces of oil and then moved to the welding process. The welding process is described as below:
1. The Machine:- This is a computer controlled electrical capacitor discharge type stored energy pulse welding machine. This machine is fitted with top and bottom electrodes, which are used to hold and position the components prior to welding. Electrodes are made to suit the components to be welded.
The sequence of welding is illustrated in FIGURE 8,9,10 & 11.
Before start of the welding sequence, when the mains power is switched on the capacitor positioned in the machine to a rating of 1200 microfarad gets charged to the required level between 1700 to 2100 Joules of energy. The machine functions such that the top electrode moves down under a hydraulic pressure required for welding between 29 to 31 bars.
When the sequence is switched on, electrical energy passes through the weld preparation area and with the electrode pressure, satisfactory welding takes place.
Conventional resistance welding process which produces more amount of heat on the components resulting in weld flash and distortion. These are detrimental to the product. Unless a particular type of welding process is identified which will not have the above problems, the present process of joining through brazing process cannot be replaced. Stored energy capacitor discharge type of welding process provides solution to the above problems.
This process gives the right amount of energy for welding and no more. Hence weld flashes donot occur and there is no over heating, hence no distortion of the components. Moreover, input voltage variations donot affect the product. Because the capacitor Is getting charged from the mains supply, when the welding donot take place.
The right amount of energy is then discharged to the components under welding. Hence everytime the same energy is discharged. This ensures better quality of welded components.
The Computer fitted onto the machine, records all the welding parameters for every component, so that they will be useful for documentation purposes.
The components thus welded has to go through rigorous quality checks, shear and pull tests on the welded joints. Moreover, air pressure leak tests are also
carried out for 100% of components, to ensure that every component passed will have leak proof joint. FIGURES 10 & 11 show components after welding. Welded joints have to withstand a shear load of 1200 kgs and a pull load of 900 kgs. While testing, the parent metal should pull out at the welded joint.
Shear and pull loads on the joints are done on Universal testing machine available in the metallurgical laboratory.
To conclude, the new process is the right one for these high pressure hydraulic fittings used for Automobile brakes.
We claim :
1. A method of manufacture of metallic brake hose end fittings
comprising a selected welding of specially machined skirt and body
characterised in that, the welding is done by means of electrical
resistance welding in which electrical energy is produced from a
stored energy capacitor type of equipment.
2. A method of manufacture of metallic brake hose end fittings as
claimed in claim 1 wherein the electrical energy is of the order -of
1700 to 2100 joules at a pressure of 30.1 bars.
3. A method of manufacture of metallic brake hose end fittings as
claimed in claims 1 and 2 wherein the capacitor rating is 1200
4. A method of manufacture of metallic brake hose end fittings as
claimed in claims 1, 2 and 3 substantially as herein described with
reference to the accompanying drawings.
|Indian Patent Application Number||2831/MAS/1998|
|PG Journal Number||30/2009|
|Date of Filing||21-Dec-1998|
|Name of Patentee||BRAKES INDIA LIMITED|
|Applicant Address||PADI, CHENNAI - 600 040|
|PCT International Classification Number||B60T1/00|
|PCT International Application Number||N/A|
|PCT International Filing date|