Method of Manufacturing Shaft Gear And Its Teeth Profile Involving Forging Process
Technical Field of the present invention:
The present invention is related to manufacturing of an auto component, shaft gear with its teeth profile, wherein teeth profile of the said gear shaft is extruded in forging. The said manufactured shaft gear, due to said forging, is much advanced in structural properties, functional properties and extended working life.
Background and objective of the present invention:
Shaft gear is an important auto component, which is primarily assembled in the engine transmission systems, and is supposed to perform its action in very stressful and high temperature conditions. In case of any manufacturing defect, wrong selection of material for manufacturing, prolong functioning of the engine and involvement of any such error/functioning/mishandling etc. the said component may undergo any type of fatigue and may require replacement.
The conventional method utilized for manufacturing of such shaft gear primarily involves cold extrusion process using the extrusion die; supported by other machining and shaping operations. Various schematic steps preferably involved in conventional process for manufacturing such shaft gear and creation of its teeth profile are shown in the following table:
(Table Removed)
(Schematic steps involved in conventional manufacturing of the shaft gear with its teeth profile therein)
The raw material (cold drawn coil), after necessary preliminary treatment like annealing and phosphating therein, is subjected to cold extrusion (1 to 5 stn.; cold part former). During the said cold extrusion the work piece takes the virtual shape of the shaft gear and then it is further treated under various steps, namely CNC-I, shaping towards creation of teeth profile of the said shaft gear, CNC-II, deburring, thread rolling, case carburization, shot blasting induction annealing straightening, gear rolling, angular
wheel grinding (or optionally hard part turning), cylindrical grinding etc. All these steps involved in the manufacturing of said shaft gear with teeth profile are mainly performed towards producing the said auto component with all desired/preferred structural and functional properties.
However, due to conventional cold extrusion process, followed by supporting multiple machining and shaping processes involved in the said conventional manufacturing of the shaft gear with teeth profile, said auto component created gets associated with certain drawbacks, namely:
(i) Not sufficient structural strength,
(ii) Not sufficient stress tolerance,
(iii) Not enough abrasive strength towards proper performance in high
temperature environments and performing in critical conditions without
fatigue.
The application of single step forging process for the same purpose is nowhere in practice; mainly due to following reasons:
(i) Technical complications in die designing for commercial production of shaft gear with teeth profile;
(ii) Non-achievement of ideal forging conditions for producing commercially acceptable shaft gear with teeth profile;
(iii) Involvement of so many dimensional aspects of the said auto component of various size range, namely creation of the central shaft length with desired range of diameter, size optimization of the said auto component, teeth formation etc., which are difficult to consider in one single standardized
process, mainly towards achieving all required and preferred structural and functional features of the said auto component.
Extrusion is a machining process that forces softened metal bar through a die. A die is a piece or pieces of steel configured for a specific end product. The conditioned metal is forced through a die, and, depending on the design of the die, an extruded component of specific shape is formed. Once the metal bar is extruded through a die, it is cooled and cut to length from its bar form (the continuous length that has been extruded through the die). Each time the blade drops, a new piece of the extruded component is created. Once cut to size, there is at least one refining process that smoothes rough edges and perfects the extruded component towards finishing.
Forging is the process of pressing, hammering, or compressing metal into a desired form. This process creates metal that is exceedingly strong. The metal that is forged is never melted, but it is softened so it can be manipulated. The forging of metal results in creating products that is stronger and more resilient than any other process of metal working. Due to the precise temperatures, other such conditions involved and the additives required to prohibit the metal to be forged from bonding with the steel material of the die, the forging process becomes complicated and challenging and hence requires very high skills and resources.
Actually it is an important fact that the forging process begins with extrusion. Conventionally the metal is extruded into round bars that are straightened and cut to the desired length. The straightening process strengthens the metal piece and actually changes the metal composition. The extruded bars are then cut into plugs (short pieces
from the bar), reheated to make them pliable, and then pressed into component (fitting) making dies.
The confusion between forged and extruded fittings spills over into their uses, considering that one can find the same component/fitting shapes made by both processes. The real difference lies in the strength of the product. Forged components are much stronger than extruded ones. Extruded components are more than adequate for low pressure, low vibration purposes like hinges and railings. Forged components/fittings are more appropriate for performing in all environments involving very high stress/abrasion, high temperature and prolong non-stop functioning without fail, for example in automobiles and in industrial purposes like plumbing and electrical components.
Therefore, the present invention is a noble effort towards achieving a method of manufacturing the said shaft gear with teeth profile primarily performing cold gear extrusion with centre and teeth forming in forging operation therein, supported with some secondary steps, wherein the teeth profile is extruded in the forging operation only; and wherein the conventional centering & facing operation as well as the shaping operations from the presently proposed manufacturing method are eliminated. Due to creating the whole shaft gear component in forging only, it saves considerable amount of material, time and efforts, and enough resources; hence helps in reducing the manufacturing costs, and improving the structural and functional properties/life of said manufactured component herein.
The prime objective of the present invention is to propose a novel method for manufacturing the shaft gear with teeth profile, wherein the said shaft gear and mainly
its teeth profile are achieved in forging itself, and wherein the said forged work piece is further subjected to other structural and functional property enhancer steps.
Another prime objective of the present invention is to propose a novel method for manufacturing the shaft gear with teeth profile, wherein the said method of manufacturing is characterized by performing the cold gear extrusion with the center (1 to 5 station; cold part former), and the teeth profile of the shaft hear is extruded in the said forging operation therein.
Another objective of the present invention is to propose a novel method for manufacturing the shaft gear with teeth profile, wherein the said method of manufacturing is characterized by elimination of conventional centering & facing operation as well as the shaping operation thereof.
Further another objective of the present invention is to propose a shaft gear with teeth profile, which is characterized by its advanced properties in comparison to conventional such shaft gear with teeth profile, mainly in terms of structural strength, stress tolerance, abrasive strength towards proper performance in high temperature environments and performing in critical conditions without fatigue etc., primarily due to creation of complete component including the teeth profile therein in forging.
Another objective of the present invention is to propose new die(s) designed for performing the said cold gear extrusion and teeth forging operation in the state-of-the-art manner towards creating the said shaft gear and extruding its teeth profile in variable optional range of desired shape, size, dimension, surface pattern and configuration.
Statement of the present invention:
The present invention is intended to propose a novel method for manufacturing the shaft gear with teeth profile, wherein the said shaft gear and its teeth profile are achieved in forging itself, and wherein the said forged work piece is further subjected to other structural and functional property enhancer steps; and wherein the method of manufacturing is characterized by performing the cold gear extrusion with the center (1 to 5 station; cold part former) and the teeth profile of the shaft hear is extruded in the said forging operation only; and wherein the said method of manufacturing is further characterized by elimination of conventional centering & facing operation as well as the shaping operation thereof; and
the present invention is further intended to propose a shaft gear with teeth profile, which is characterized by its advanced properties in comparison to conventional such shaft gear with teeth profile, mainly in terms of structural strength, stress tolerance, abrasive strength towards proper performance in high temperature environments and performing in critical conditions without fatigue etc., primarily due to creation of complete component including the teeth profile therein in forging; and
the present invention is further intended to propose new die(s) designed for performing the said cold gear extrusion and teeth forging operation in the state-of-the-art manner towards creating the said shaft gear with its teeth profile in variable optional range of desired shape, size, dimension, surface pattern and configuration.
Description of the present invention:
Shaft gear with its specific teeth profile is an important machine component and it finds its significant role in the power transmission and in functioning of a number of engines and engine based machineries, and in regulating the speed, magnitude, and direction of a power source. The presently described shaft gear herein preferably has important role in the power transmission in the automobiles, and more preferably in the power transmission in motor-cycles.
Therefore the presently proposed and substantially described method of manufacturing the shaft gear with its specific teeth profile is very significant, because due to such novel method of manufacturing, the said auto component achieves advanced structural and functional properties, is produced in comparatively much economical manner, and is produced much quickly to meet the requirements of herein concerned industry. In case of any manufacturing defect, the said component may cause a malfunction to deteriorate the engagement with another corresponding wheel component to make a noise at the engaging portion continuously in operation time and transmission efficiency; and therefore may cause undesired and untimely fatigue and may require replacement.
In the presently proposed method all the structural features of the desired auto component herein, that is the central shaft of desired diameter and dimension as well as the complete teeth profile of the gear are produced in the forging itself, mainly by performing cold gear extrusion with centre and teeth forming in forging operation therein. Main schematic steps are represented in the following table:
(Table Removed)
(Schematic steps involved in presently proposed new method of manufacturing of the shaft gear with its teeth profile therein)
The above mentioned table clearly represents that in this proposed method, the raw material, which is the cold drawn coil, is first treated by annealing and phosphating and then after, it is subjected to forging, which is by way of involving cold gear extrusion with centre (1 to 5 station), wherein the complete shaft gear body as well as all major
structural features of the complete teeth profile of the gear, get formed in the forging operation.
After performing the said forging operation and doing its visual inspection, the forged component is subjected to further refining and other property enhancer operations are performed. In conventional practice 'centering and facing operation' was performed after the cold extrusion of the work piece, and after performing CNC-I operation, the shaping operation of the work piece was performed. But in present method of manufacturing, due to suitably designed forging operation, steps like 'centering and facing' and 'shaping' gets eliminated.
Therefore, after said forging and visual inspection, the forged component, in stepwise manner, is subjected to CNC-I and CNC-I I machining, deburring, thread rolling, case carburizing, shot blasting, induction annealing, straightening, gear rolling, angular wheel grinding/(Hard part turning, which is optional), cylindrical grinding, final inspection (PDI), oiling & packing, and storage in FG store. The secondary operations after forging further helps in enhancing the stress bearing capacity, making corrosion resistant, compensating the negative effects of machining operations performed during the manufacturing process, increasing the hardness of the upper surfaces of the component and its teeth created. Further such steps help in refining the structural features of the teeth profile of the shaft gear, viz. the circular pitch, chordal pitch, pitch surface, root circle/base circle/pitch circle/outside or addendum circle, circular thickness of the tooth, smoothing the face of the tooth, creating clear bottom land/top land/fillet/flank etc. As the teeth profile of a gear is most important feature of the gear, which in combination with other gear(s), play its role in power transmission. Its internal
strength against abrasion and abnormal temperature conditions is very important for ling functional life of the shaft gear, and therefore preparation of the teeth profile of the said shaft gear is very significant herein.
The description of the proposed method of manufacturing the shaft gear with its teeth profile is further supplemented herein below by certain drawings. Short titles of these drawings are as under:
Figure 1: It represents the conventional schematic plan for manufacturing of an embodiment of the shaft gear and its teeth profile, wherein it mainly involves conventional steps like cold extrusion, centering & facing, shaping etc. and other supportive machining steps thereof.
Figure 2: It represents the new and presently proposed schematic plan for manufacturing of an embodiment of the shaft gear with its teeth profile, wherein after pre-conditioning of the metal bar by annealing and phosphating, it is mainly subjected to forging by way of cold gear extrusion with center (1 to 5 stn.)(cold part former), wherein the teeth profile gets extruded in forging itself. The said depicted plan shows that operations like 'centering & facing' and 'shaping' are eliminated from the newly proposed method of manufacturing the shaft gear with teeth profile.
Figure 3: It represents the schematic view of an embodiment of shaft gear with its teeth profile, wherein whether this embodiment is achieved by conventional root of Figure 1 or by new method of Figure 2, its outer look is similar; but due to involvement of forging in new method of Figure 2, the internal structure, the internal strength and other
structural/functional features of the embodiment produced by new plan of Figure 2 is much superior than that of conventional plan of Figurel.
The newly proposed method, as depicted in Figure 2, is suitable for producing variety of embodiments of presently described shaft gear with teeth profile, wherein desired dimension, shape, size, length/diameter of the shaft, teeth profile of the gear, surface pattern and configuration etc. of these embodiments are achieved by suitably designing the die according to the desired dimensional and structural features of the said shaft gear, wherein the said die is provisioned for extruding the teeth profile of the said gear in forging itself. By making such suitable die and producing the whole body of the said shaft gear with its teeth profile in forging proposed herein, the whole method of manufacturing process gets redefined and becomes much simpler and economical and thus the said shaft gear also achieves advanced structural and functional features and comparatively extended functional life.
Scope of the present invention:
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present invention as defined.

We Claim:
1. New method of manufacturing shaft gear and its teeth profile by primarily involving forging process using a suitable die, particularly performing cold gear extrusion with centre (1 to 5 station, cold part former) and extruding the teeth profile in forging therein, wherein the said method is characterized by not performing of the centering & facing operation, and the shaping operation.
2. A method of manufacturing shaft gear and its teeth profile, as claimed in claim 1, wherein the said method is characterized by carrying out forging operation therein on annealed and phosphate steel coil, mainly by means of carrying out cold gear extrusion with center (1 to 5 station, cold part former) and achieving the teeth profile forming in forging.
3. A method of manufacturing shaft gear and its teeth profile, as claimed in claim 1 wherein the said method is characterized by the structural and functional properties of the manufactured shaft gear with teeth profile, mainly in terms of its high stress bearing capacity, high corrosion resistance, high temperature tolerance and high internal structural strength.
4. A method of manufacturing shaft gear and its teeth profile, as claimed in claim 1, wherein the said method of manufacturing the said shaft gear is characterized by carrying out of certain stepwise operations after performing of the said forging operation.
5. A method of manufacturing shaft gear and its teeth profile, as claimed in claim 1, wherein said forging operation applies a suitable closed die for creating structural features like central shaft of specific diameter, complete teeth profile and other major surface elevations/depressions of the said shaft gear component.
6. A method of manufacturing shaft gear and its teeth profile, as claimed in claim 1,
wherein the said shaft gear with its teeth profile, optionally of different shape,
size, dimension, teeth profile, surface pattern and configuration is manufactured
by the said method involving the forging process by way of performing cold gear
extrusion with centre and teeth extrusion in forging therein, using suitable closed
die of corresponding shape, size, dimension, teeth profile, surface pattern and
configuration therein.
7. A method of manufacturing shaft gear and its teeth profile, as claimed in claim 1,
wherein new die(s) designed for performing the said cold gear extrusion and
teeth forging operation in the state-of-the-art manner towards creating the said
shaft gear and extruding its teeth profile in variable optional range of desired
shape, size, dimension, surface pattern and configuration.
8. A method of manufacturing shaft gear and its teeth profile, as claimed in claim 1,
wherein the said method, after performing said forging operation towards
creating the complete body of shaft gear with its teeth profile, is characterized by
carrying out of additional supporting operations in stepwise manner, namely CNC
machining, deburring, thread rolling, case carburizing, short blasting, induced
annealing, straightening, gear rolling, angular wheel grinding/(Hard part turning,
optional), and cylindrical grinding.
9. A method of manufacturing shaft gear and its teeth profile substantially as herein
described and illustrated in the figures of the accompanying drawings.