METHOD OF MANUFACTURING ARMATURE SHAFT WITH TEETH PROFILE
INVOLVING FORGING PROCESS
Technical Field of the present invention:
The present invention is related to manufacturing of an auto component, armature shaft with its teeth profile, wherein the said shaft is formed under cold gear extrusion with teeth forging. The said manufactured armature shaft, due to teeth forging, is much advanced in structural properties, functional properties and extended working life.
Background and objective of the present invention:
Armature shaft is the primary shaft on which the armature is mounted in a starter or generator. 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.
The conventional method utilized for manufacturing of such armature shaft and its teeth profile firstly involves cold extrusion process using the extrusion die, optionally supported by some machining processes for creating the main shaft body, and then performs hobbing operation towards teeth cutting. Main schematic steps preferably involved in conventional process for manufacturing such armature shaft with its teeth pattern are shown in the following table:
(Table Removed)
(Schematic steps involved in conventional manufacturing of the armature shaft and its teeth profile)
Conventionally the raw material is subjected to cold extrusion (1 to 5 stations) on cold part former using the suitable extrusion die, mainly towards creating the cylindrical body of armature shaft, without teeth profile. Then on the circumferential face of one end of the cylindrical shaft length, duly provisioned therein, cutting of teeth profile by hobbing operation is performed. In case of high roughness on the surface of said shaft, certain refining operations are optionally performed.
In an another conventional method, the cylindrical shaft length is created in cold extrusion, followed by certain forging operation towards creation of other surface features, such as any small diameter portion in said shaft length therein or creation of the suitable circumferential face on one end of the cylindrical length of the extruded work piece where teeth will be formed in next step therein. Then in the next step the teeth pattern is cut through machining, preferably hobbing.
However, due to conventional cold extrusion process, followed by supporting multiple machining and teeth cutting processes, the said conventional manufacturing of the armature shaft with its teeth profile on one end, gets associated with certain drawbacks, namely:
(i) Not sufficient structural strength,
(ii) Not sufficient stress tolerance,
(iii) Not enough abrasive strength towards proper continuous performance
in high temperature environments and performing in critical conditions
without fatigue, (iv) Noisy functioning in association with teeth pattern of another
corresponding gear tool assembled therein.
The application of proposed single step forging process towards forging of teeth during cold gear extrusion of the said armature shaft is nowhere in practice; mainly due to following reasons:
(i) Technical complications in die designing for commercial production of armature shaft with its teeth pattern on one end of its cylindrical length;
(ii) Non-achievement of ideal forging conditions for producing commercially acceptable armature shaft with its teeth pattern;
(iii) Involvement of so many optional dimensional aspects of the said auto component of various size range, namely creation of the cylindrical 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, usually 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 carrying out of next step of the manufacturing.
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 armature shaft with its teeth profile primarily performing the cold gear extrusion and simultaneously the teeth forging operation therein, supported with some secondary optional steps towards refining and finishing it, wherein the said teeth profile is extruded in the forging operation only; and wherein the conventional hobbing operation is eliminated from the presently proposed manufacturing method. Thus, the creation of the whole armature shaft with its teeth pattern in cold gear extrusion in teeth forging, 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 armature shaft with its teeth profile, wherein the said armature shaft and its teeth profile are achieved in simultaneous cold gear extrusion with teeth forging itself, and wherein the said forged component may optionally undergoes other structural and functional property enhancer steps.
Another prime objective of the present invention is to propose a novel method for
manufacturing the armature shaft with its teeth profile, wherein the said method of
manufacturing is characterized by performing the cold gear extrusion with teeth forging (1 to 5 station; cold part former), wherein the teeth profile of the armature shaft is simultaneously extruded in forging during the formation of whole cylindrical body of the said armature shaft, without performing any teeth cutting operation, namely the hobbing operation.
Another objective of the present invention is to propose a novel method for manufacturing the armature shaft and its teeth profile, wherein the said method of manufacturing is characterized by elimination of conventional hobbing operation towards cutting the teeth profile on the circumferential face of one end of the cylindrical shaft length, duly provisioned therein.
Further another objective of the present invention is to propose an armature shaft with its teeth profile, which is characterized by its advanced properties in comparison to conventional such shaft and its teeth profile, mainly in terms of structural strength, stress tolerance, abrasive strength towards proper performance in high temperature environments and continuous 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 a new die designed for performing the said forging operation in the state-of-the-art manner towards creating the said armature shaft with its teeth profile in variable optional range of 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 armature shaft with its teeth profile, wherein the said armature shaft and its teeth profile are achieved in simultaneous cold gear extrusion with teeth forging itself, and wherein the said forged component may optionally undergoes other structural and functional property enhancer steps; and wherein the said method of manufacturing is characterized by performing the cold gear extrusion with teeth forging (1 to 5 station; cold part former), wherein the teeth profile of the armature shaft is simultaneously extruded in forging during the formation of whole cylindrical body of the said armature shaft, without performing any teeth cutting operation, namely the hobbing operation; and wherein the said method of manufacturing is characterized by elimination of conventional hobbing operation towards cutting the teeth profile on the circumferential face of one end of the cylindrical shaft length, duly provisioned therein; and
the present invention is further intended to propose an armature shaft with its teeth profile, which is characterized by its advanced properties in comparison to conventional such shaft and its teeth profile, mainly in terms of structural strength, stress tolerance, abrasive strength towards proper performance in high temperature environments and continuous 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 a new die designed for performing the said forging operation in the state-of-the-art manner towards creating the
said armature shaft with its teeth profile in variable optional range of shape, size, dimension, surface pattern and configuration.
Description of the present invention:
Armature Shaft with its specific teeth profile at one end of the cylindrical length therein is mounted in a starter or generator, and it plays its significant role in the power transmission and in functioning of a number of engines and power sources. The presently described armature shaft herein preferably finds its role in the power transmission mechanism of motor-cycles.
Therefore the presently proposed and substantially described method of manufacturing said armature shaft with its specific teeth profile is very significant, because due to such novel method of manufacturing, the said shaft and its teeth profile 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 the presently proposed method all the structural features of the armature shaft herein of desired diameter and dimension as well as the complete teeth profile therein are produced in the forging itself, mainly by way of carrying out simultaneous cold gear extrusion with teeth forging (1 to 5 station). 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)
Due to such method of directly forming the complete body of said armature shaft and its teeth profile, the said component achieves several structural and functional features, such as:
(i) Structural strength: Forging also provides a degree of structural integrity that is unmatched by other metal working processes. Forging eliminates internal voids and gas pockets that can weaken metal parts. By dispersing segregation of alloys or non-metallic, forging provides superior chemical uniformity. Predictable structural integrity reduces part inspection requirements, simplifies heat treating and matching, and ensures optimum part performance under field-load conditions.
(ii) Directional strength: By mechanical deforming the heated metal under tight controlled condition, forging produces predictable and uniform grain size and flow characteristics. Forging stock is also typically pre-worked to refine the dendritic structure of the ingot and remove defects or porosity. These qualities translate into superior metallurgical and mechanical qualities, and deliver increased directional strength in the final part.
(iii) Impact strength: Parts can also be forged to meet virtually any stress, load or impact requirement. Proper orientation of grain flow assures maximum impact strength and fatigue resistance. The high-strength properties of the forging process can be used to reduce sectional thickness and overall weight without compromising final part integrity.
(iv) Grain Flow: Through forging process directional alignment can deliberately be oriented in a direction requiring maximum strength. This also yields ductility and resistance to impact and fatigue. By no any other process such grain flow or directional strength is achieved. During mechanical processing, the unidirectional grain flow has been cut when changing contour, exposing grain ends. This renders the material more liable to fatigue and more sensitive to stress corrosion cracking.
(v) Cost-effectiveness: Forging helps in directly producing the desired product, wherein it requires certain secondary operations only and therefore it provides possibility for achieving production of high quantity of components and thus is also very cost effective.
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 schematic view of one embodiment of said armature shaft with its teeth profile.
Figure 2: It represents the schematic plan of conventional manufacturing of an armature shaft and its teeth profile.
Figure 3: It represents the schematic plan of the newly proposed method of manufacturing armature shaft with its teeth profile.
Figure 1 represents the schematic view of one embodiment of said armature shaft with its teeth profile, wherein the said teeth profile is created on the circumferential face of the duly provisioned end of the cylindrical length of the said shaft, and wherein the teeth profile is formed in forging, preferably alongwith the complete body of said armature shaft by performing cold gear extrusion with teeth forging (1 to 5 station; cold part former).
The conventional method for manufacturing the armature shaft with its teeth profile at the one end of cylindrical body therein, as depicted in schematic plan of Figure 2, is formed by subjecting the raw material received to cold extrusion for making the cylindrical body of specific diameter, using the extrusion die; followed by cutting the desired teeth profile therein using hobbing operation, on a particular circular surface segment of one end of the cylindrical length of the said extruded shaft body. There may be application of at least one machining operation performed after hobbing, which is mainly to achieve better surface finish and improvement in the structural/functional features of said produced shaft and its teeth profile. Due to performing extrusion process followed by hobbing operation, the conventional method is comparatively less efficient and non economical, due to involvement of more resources and time.
Figure 3 provides a novel method of manufacturing the armature shaft with the teeth profile, wherein the raw material is subjected to forging, by means of simultaneously performing the cold gear extrusion with teeth forging (1 to 5 station) by using suitable die(s) competent for carrying out such extrusion and forging operation, designed to support the whole shaft body and its teeth profile formation. Thus in this newly proposed method, the conventional hobbing operation towards teeth cutting is completely eliminated. In case there is further requirement of surface refining or bur cleaning from the surface of the produced armature shaft, certain operations like deburring, short blasting etc are optionally performed, but normally such machining operations are not required.
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 armature shaft and its teeth profile, wherein the said armature shaft and its teeth profile are achieved in simultaneous cold gear extrusion with teeth forging operation using suitable die(s) for such simultaneous operation, and wherein the said forged component may optionally undergoes other structural and functional property enhancer operations; and wherein the said method of manufacturing is characterized by eliminating conventional hobbing operation towards teeth formation.
2. A method of manufacturing armature shaft and its teeth profile, as claimed in claim 1, wherein the said method is characterized by creating the whole body of said armature shaft and its teeth profile by carrying out cold gear extrusion with teeth forging (1 to 5 stn.)(cold part former) and achieving the said teeth profile in forging itself.
3. A method of manufacturing armature shaft and its teeth profile, as claimed in claim 1 wherein the said method is characterized by the structural and functional properties of the manufactured armature shaft with its teeth profile, mainly in terms high stress bearing capacity, high corrosion resistance, high temperature tolerance and high internal structural strength of the said armature shaft and its teeth profile.
4. A method of manufacturing armature shaft and its teeth profile, as claimed in claim 1, wherein said forging operation applies a suitable closed die for creating structural features like cylindrical body of the armature shaft with specific
diameter, complete teeth profile and other major surface elevations/depressions of the said armature shaft component.
5. A method of manufacturing armature shaft and its teeth profile, as claimed in
claim 1, wherein the said armature shaft with its teeth profile, optionally of
different shape, size, dimension, teeth profile, surface pattern and configuration
is manufactured by the said method involving the cold gear extrusion with
simultaneous teeth forging, using suitable die(s) of corresponding shape, size,
dimension, teeth profile, surface pattern and configuration therein.
6. A method of manufacturing armature shaft and its teeth profile, as claimed in
claim 1, wherein the said method, after performing said forging operation towards
creating the complete body of armature shaft with its teeth profile, is
characterized by carrying out of optional operations, primarily towards surface
refining.
7. A method of manufacturing armature shaft and its teeth profile substantially as
herein described and illustrated in the figures of the accompanying drawings.