METHOD OF MANUFACTURING LUG GEAR INVOLVING HOT
FORGING PROCESS
Field of the present invention:
The present invention is related to a novel method of manufacturing lug gear, primarily to be used in motor cycles, by using hot forging process (Upsetting & forming) on horizontal hot part forging, followed by normalization thereof. The present invention eliminates the conventional method of using shot blasting followed by warm forging and controlled cooling thereafter. The hot forged and normalized lug gear component herein, undergoes certain supporting steps namely piercing, CNC machining, deburring, nobbing, hardening, shot blasting, honing, luberite coating etc.
By changing the process and by making the component in hot forging, instead of making it in vertical warm forging, it is now possible to achieve large production in lesser time.
Background and objective of the invention:
Lug gear is an important gear component in a power transmission system, particularly in automobiles, and more particularly in motor cycles. The lug gear used in motor-cycles is depicted in figure 1 herein below. Such gear component is conventionally manufactured by a series of processes, such as shot blasting, warm forging, controlled cooling thereafter, and piercing by
vertical press, CNC machining, deburring, hobbing, hardening (case carburizing), honning, lubrite coating etc. The schematic plan for performing stepwise processes performed towards producing one embodiment of such lug gear component is as follows:
Conventional method:
(Table Removed)
Shot Blasting or Abrasive blasting is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface, or remove
surface contaminants. A pressurized fluid, typically air, or a centrifugal wheel is used to propel the media.
The temperature range for the warm forging of steel, runs from above room temperature to below the recrystallization temperature, or from about 800 to 1,800 degrees Fahrenheit. However, the narrower range of from 1,000 to 1,330 degrees Fahrenheit is emerging as the range of perhaps the greatest commercial potential for warm forging. Compared with cold forging, warm forging has the potential advantages of reduced tooling loads, reduced forging press loads, increased steel ductility, elimination of need to anneal prior to forging, and favorable as forged properties that can eliminate heat treatment. Conventionally warm forging has a number of cost-saving advantages which underscore its increasing use as a manufacturing method.
However for commercial production, time is very important factor towards deciding the cost of any produce, such as lug gear herein. An auto component like lug gear, which has to perform perfectly in very high abrasion and in very critical environment, require to be manufactured in such a manner that it has enough structural strength. The conventional method of manufacturing a lug gear, mainly the involvement of steps like initial shot blasting, then vertical warm forging (1 & 2; KP630T), and then controlled cooling, are comparatively time consuming. In present time the manufactures of lug gear are exploring all possibilities of meeting the market demand, by cutting down the time consumed in producing such lug gears.
Therefore the present invention proposes a new method of manufacturing the lug gear, preferably as shown in Figure 1 herein below, wherein it eliminates the conventional set of operations, namely shot blasting, then vertical warm forging (1 & 2; KP630T), and then controlled cooling; and wherein the new proposed method mainly involve hot forging (Upsetting & forming) on horizontal hot former using a suitable closed die for forming the embodiment of said lug gear component, followed by normalization of the forged component, piercing by vertical press, and CNC machining operations. By the newly proposed method, mainly due to involvement of hot forging process it is now possible to produce substantially larger quantity of said lug gear, in comparison to the conventionally practiced method.
Main challenges in achieving the said lug gear through hot forging process are:
• Technical complications in die designing for commercial production of lug gear;
• Non-achievement of ideal hot forging (upsetting and forming) conditions
for producing commercially acceptable lug gear;
The prime object of the present invention is to propose a new method for manufacturing lug gear, wherein the said gear is the component is achieved in hot forging, instead of making it in vertical warm forging; wherein the hot forged gear component, after normalization, is subjected to certain conventional processes in stepwise manner, namely piercing by vertical press,

CNC machining, deburring, nobbing, hardening (case carburizing), shot blasting, honing, lubrite coating etc.
Another object of the present invention is to propose a lug gear, preferably as as depicted in Figure 1, which is formed by involving horizontal hot forging process (upsetting and forming), eliminating vertical warm forging therein.
Another object of the present invention is to propose a new method of manufacturing the lug gear component involving hot forging (upsetting & forming , on horizontal hot former), preferably shown in figure 1, wherein the said method is characterized by quicker production of the said lug gear component towards comparatively larger production than conventional method involving vertical warm forging.
Another object of the present invention is to propose a new method of manufacturing the lug gear component involving hot forging (upsetting & forming , on horizontal hot former), preferably shown in figure 1, wherein the said method is characterized by material saving during the manufacturing, primarily due to upsetting and hot forging.
Another objective of the present invention is to propose a new closed die, compatible to carry out the hot forging operation (upsetting & forming) on horizontal hot part former, towards forming the said lug gear, wherein said lug gear formed is of variable optional dimension, diameter, shape, size, groove pattern, and surface pattern therein.
Statement of the present invention:
The present invention is intended to propose:
• a new method for manufacturing lug gear, wherein the said gear is the component is achieved in hot forging, instead of making it in vertical warm forging; wherein the hot forged gear component, after normalization, is subjected to certain conventional processes in stepwise manner, namely piercing by vertical press, CNC machining, deburring, hobbing, hardening (case carburizing), shot blasting, honing, lubrite coating etc.;
• a lug gear, preferably as depicted in Figure 1, which is formed by involving horizontal hot forging process (upsetting and forming), eliminating vertical warm forging therein;
• a new method of manufacturing the lug gear component involving hot forging (upsetting & forming , on horizontal hot former), preferably shown in figure 1, wherein the said method is characterized by quicker production of the said lug gear component towards comparatively larger production than conventional method involving vertical warm forging;
• a new method of manufacturing the lug gear component involving hot forging (upsetting & forming , on horizontal hot former), preferably shown in figure 1, wherein the said method is characterized by material saving during the manufacturing, primarily due to upsetting and hot forging; and
• a new closed die, compatible to carry out the hot forging operation (upsetting & forming) on horizontal hot part former, towards forming the said lug gear, wherein said lug gear formed is of variable optional dimension, diameter, shape, size, groove pattern, and surface pattern therein.
Description of the present invention:
The present description discloses an invention which is related to a novel method for manufacturing lug gear, preferably as shown in Figure 1, wherein the said method involves hot forging (upsetting and forming) operation on horizontal hot part former towards forming the lug gear body; eliminating the conventional vertical warm forging therein. During the said hot forging operation all essential structural features of the lug gear component are created.
During the manufacturing process a number of operations are performed towards creation of the main embodiment of the lug gear component produced, creation of other structural features through certain machining operation(s), refining and smoothening of the component surface(s), strengthening of the said gear component etc. The conventional method mainly performs a series of processes towards creating the main embodiment of the lug gear, which mainly include billet sharing (SCM 415HV; as per HHML spec), shot blasting, vertical warm forging 1 & 2 (KP630T), and controlled cooling. Due to performing such series of operations, the
conventional manufacturing method becomes time consuming and it also creates substantial loss of lug gear making material.
Therefore, the new method proposed herein is such that it eliminates aforesaid set of conventional operations, that is: billet sharing (SCM 415HV; as per HHML spec), shot blasting, vertical warm forging 1 & 2 (KP630T), and controlled cooling.
The new method, after receiving the raw material, mainly involves performing of hot forging (Upsetting & Forming) on horizontal hot part former, and then after normalization of the hot forged embodiment of the lug gear.
Upset forging increases the diameter of the work piece by compressing its length. Hot forging is the plastic deformation of metal at a temperature and strain rate such that recrystallization occurs simultaneously with deformation, thus avoiding strain hardening. For this to occur, high work piece temperature (matching the metal's recrystallization temperature) needs to be attained throughout the process.
The automatic hot forging process involves feeding mill-length steel bars/work-piece of a particular diameter into one end of the forging machine machine/press (which is preferably a hydraulic press herein) at room temperature and hot forged products emerge from the other end. This all occurs very quickly; usually the small parts, like in the present case of lug-gear, can be made at a rate of 150 to 180 parts per minute (ppm). The forged part herein, attains almost all essential structural features of the lug gear. The
main advantages to this process are: (i) its high output rate, (ii) ability to accept low cost materials, and (iii) little labor required to operate the machinery. There is no flash produced so material savings are between 20 and 30% over conventional forging herein. The final product remains at a consistent very high temperature, preferably at around 1,050 °C(1,920 °F), so normalization by way of air cooling in order to relieve stress, will result in a part that is still easily machinable (the advantage being the no requirement of annealing required after forging). Tolerances are usually ±0.3 mm (0.012 in), surfaces are clean, and draft angles are preferably in the range of 0.5 to 2°. Tool life is nearly double that of conventional forging because contact times are few fractions of a second.
The hot forged part undergoes normalization, in which it is cooled in air to a temperature substantially below the transformation range, in order to relieve stress. During the hot forging the material of the work piece attains a very high temperature and therefore due to gradual air cooling during normalization it gains enough hardness, though the material of said normalized component is still so soft and well conditioned that it becomes very convenient to carry our all other supporting gear manufacturing steps.
In next stage, the normalized lug-gear part, is subjected to several stepwise processes, namely piercing, CNC machining, deburring, hobbing, hardening (case carborizating), shot blasting, honing, and luberite coating. A schematic plan followed for carrying out the newly proposed method of manufacturing an embodiment of said lug gear component is as under:
New proposed process:
(Table Removed)
The said proposed method of manufacturing the lug gear involving hot forging may further be comparatively elaborated with the help of schematic drawings.

Figure 2: It depicts important steps involved in the conventional schematic plan for manufacturing an embodiment of the lug gear component, preferably as depicted in Figure 1 herein.
Figure 3: It depicts important steps involved in the schematic plan for manufacturing an embodiment of the lug gear component by the presently proposed method for manufacturing lug gear involving hot forging, preferably as depicted in Figure 1 herein.
For performing the said hot forging operation (upsetting and forming), on horizontal hot part former, on the work piece of pre-determined dimension and diameter, it is important to have suitable die, which is preferably a closed die herein. The said closed die is designed according to the shape, size, diameter, surface pattern and complete dimensional features of the said lug gear, preferably as depicted in Figure 1 herein. Various embodiments of the said lug gear, in various optional and different shapes, sizes, dimensions, features towards functionality of the said gear component, surface pattern and configuration therein, are manufactured by the present said method involving the horizontal hot forging (upsetting and forming) using suitable closed die of corresponding optional shapes, sizes, dimensions, features towards functionality of the said gear component, surface pattern and configuration therein.
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. A method of manufacturing lug gear, wherein the said method mainly involves hot forging (upsetting and forming) on horizontal hot part former using suitable die for forming the said lug gear component, followed by normalization of the forged gear part; and wherein the said forged normalized component may optionally undergoes other structural and functional property enhancer operations.
2. A method of manufacturing lug gear involving hot forging, as claimed in claim 1, wherein the said method of manufacturing lug gear is characterized by performing the hot forging (upsetting and forming) on horizontal hot part former using suitable die for forming the said lug gear component, and wherein the said method is further characterized by eliminating and not performing the conventional set of operations, namely shot blasting, then vertical warm forging and then controlled cooling, towards lug gear formation.
3. A method of manufacturing lug gear involving hot forging, as claimed in claim 1, wherein the said method is characterized by subjecting the forged and normalized said gear component towards performing supporting processes, namely piercing by vertical press, CNC
machining operations, deburring, hobbing, hardening (case carburizing), shot blasting, honing, and lubrite coating, towards refining & smoothening of the surface, creation of certain optional functional features on said lug gear body, and strengthening of the said lug gear.
4. A method of manufacturing lug gear involving hot forging, as claimed in claim 1, wherein the said hot forging (upsetting and forming) operation on horizontal hot former applies a suitable closed die for creating main body of the said lug gear, its major structural and functional features therein (preferably as depicted in Figure 1 herein) and other major surface elevations/depressions of the said lug gear component; wherein the said embodiment of the lug gear, created by hot forging herein may optionally undergoes other structural and functional property enhancer operations.
5. A method of manufacturing lug gear involving hot forging, as claimed in claim 1, wherein the said method is characterized by formation of optional embodiments of the said lug gear, in various optional and different shapes, sizes, dimensions, features towards functionality of the said gear component, surface pattern and configuration therein, are manufactured by the present said method involving the horizontal hot forging (upsetting and forming), using suitable closed die of corresponding optional shapes, sizes, dimensions, features towards
functionality of the said gear component, surface pattern and configuration therein.
6. A method of manufacturing lug gear involving hot forging, substantially as herein described and illustrated in the figures of the accompanying drawings.