FIELD OF THE INVENTION
The present invention relates to apparatus and method for developing starter pinion (gears) with forged chamfer, adapted for use in vehicle differentials and more particularly to an auto component and a method for manufacturing a starter pinion(gear) localization of a relatively complex configuration using pre-forming and cold forming mechanism and a machine finishing operation to provide a starter pinion localization of high-precisions and good yield.
BACKGROUND OF THE PRESENT INVENTION
While it is correct to say that the basic principles of the starter motor are the same today as they were when the first starter was designed, many specifics of starter design have changed considerably. For instance the pole pieces, which become powerful magnets when electricity flows through the field coils that are wrapped around them, have been replaced in most modern starters with permanent magnets. Since the energy required to magnetize the pole pieces is not needed the starter uses less power from the battery, making it more efficient. The starter pictured here is an offset gear reduction design. The advantage of this design is that it allows for a smaller, lighter starter to produce the same amount of torque as the earlier direct drive starters while using less energy from the battery. Notice the pinion gear is no longer connected to the armature shaft. In this type of design, the armature spins about 4 times faster than the pinion gear whereas in a direct drive type the pinion gear turned at the same speed as the armature.
The Folo-Thru Bendix drive comprises of the pinion and barrel assembly in the cranking position. A spring-loaded detent pin that moves into a notch cut in the spiral spline serves to lock the pinion in the crank position. This feature prevents unwanted disengagement during false starts. When the engine starts and reaches sufficient speed, centrifugal force causes the detent pin to move out of the notch, and the pinion then is driven out of mesh with the ring gear. A second pin rides on the spiral spline and acts as an anti-drift device during engine operation.
Gears, mainly with teeth provisions, are important auto components, being used in the engine transmission of motor cycles. Conventionally such gears are manufactured using machining process involving hobbing & deburring processes. Due to such conventional processes of the production of gear with teeth & forged chamfer, the auto component is associated with certain types of drawbacks, such as more consumption of resources and time; involvement of various machining steps towards formation of the central hole as well as formation of teeth profile; formation of substantial amount of wastage material etc.
A typical process for forming a starter pinion includes forging, annealing, rough machining, carburizing, hardening and finish machining operations. Despite the almost universal use of such forming processes, several drawbacks have been noted.
One such drawback relates to the initial forming of the starter pinion through forging. As those skilled in the art will appreciate, the starter pinion is typically blanked or rough-formed in a forging operation from a solid billet of steel. This forging operation is relatively inefficient because the shape of the “in-process” forging is substantially different from the final desired starter pinion shape. Another drawback concerns the machining of the starter pinions gear. The numerous machining operations that are performed typically account for more than 70% of the total cost of the starter pinion. Furthermore, the protracted nature of the machining operations often results in an average cycle time that exceeds one or more days in length.
Typically, the steel billet from which the starter pinion is formed is a low carbon steel having characteristics that are particularly well suited to both forging and machining. Such steels, however, generally lack the strength that is desired, a time consuming and costly carburization process is typically employed to create a layer of relatively high carbon steel on the surface of the gear.
There are several methods and combinations of steps available for producing Starter Pinion (gear) localization, involving diverse conditions for its production. However, the industry is continuously improving the method of manufacturing such gears, particularly in terms of improving various manufacturing as well as functionality related parameters of said Starter Pinion (gear) localization.
Accordingly, there remains a need in the art for an improved method for manufacturing a starter pinion(gear) localization of a relatively complex configuration using several processes (cold forming , pre-forming etc) to provide a starter pinion localization of high-precision and good yield of the finished product .
OBJECT OF THE PRESENT INVENTION
The main object of the present invention is to overcome the disadvantages of the prior art.
An object of the present invention is to provide a method for manufacturing a starter pinion (gear) localization assembly using pre-forming and cold forming mechanism.
Another object of the present invention is to provide a method for manufacturing a starter pinion involving machine finishing operation by the CNC machine to turn the post cold formed product yielding the near finished shape of the desired product.
Another object of the present invention is to provide a method for manufacturing a starter pinion localization, wherein said pinion is typically blanked or rough-formed in a forging operation from a solid billet of steel or alloy materials.
Another object of the present invention is to provide a method for manufacturing a starter pinion localization, wherein teeth patterns are generated on the circumferential surface of the pinion’s outer section, on its outer diameter therein, by cold-forming operation, preferably on cold former KP-250.
Another object of the present invention is to propose a new die set, suitable for horizontal hot forging towards manufacturing of a gear with teeth of variable range of desired shape, size, dimension, surface pattern and configuration, as being produced herein.
Yet another object of the present invention is to provide a method for manufacturing a starter pinion localization that increases the rate of yield of the finished product; reduces the involvement of time and resources in the production of the product and creates least wastage of materials and provides better mechanical properties.
Yet another object of the present invention is to provide a method for manufacturing a starter pinion localization that is easy to perform and involves a lower cost for their manufacture.
These and other objects of the present invention will be apparent from the drawings and descriptions herein. Every object of the invention is attained by at least one embodiment of the present invention.
SUMMARY OF THE INVENTION
The present invention is directed to a method for manufacturing a starter pinion(gear) with forged chamfer localization of a relatively complex configuration using pre-forming and cold forming mechanism and a machine finishing operation to provide a starter pinion localization of high-precision and good yield without requiring other intermediate processes such as normalizing and shot blasting.
According to an embodiment of the present invention, the method for manufacturing a starter pinion (gear) with forged chamber localization, comprises the steps of;
a. selecting a raw material to perform a pre-form operation at an ambient temperature using a suitable closed die of preferred size;
b. placing at least one said die set on said raw material of step a to form a pinion like structure;
c. forging structure of step b to cold forming operation on cold former KP-250 at an ambient temperature;
d. producing a starter pinion(gear) localization as the desired product having a plurality of net-shaped teeth with forged end chamfer on the outer portion of said starter pinion on completion of step c;
e. hardening at least a portion of said net-shaped teeth; and
f. selecting and performing a machine finishing operation for yielding the near finished shape of said product.
According to another embodiment of the present invention, the raw material used is preferably billets usually made up of steel or alloy materials and alike and plays an important role towards selecting an optimized cold-forming conditions and thereafter performing other supportive operations, depending upon the structural features of the final product, structural strength, functional features of the product etc.
According to another embodiment of the present invention, the starter pinion produced or manufactured comprises of at least 8 teeth’s and has a pressure angle of about 20 degrees.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
FIG. 1 is a schematic illustration of the proposed process of manufacturing the starter pinion localization in various stages.
FIG. 2 represents a flow diagram indicating the steps involved in manufacturing of starter pinion localization
DETAILED DESCRIPTION OF THE INVENTION
The following description includes the preferred best mode of one embodiment of the present invention. It will be clear from this description of the invention that the invention is not limited to these illustrated embodiments but that the invention also includes a variety of modifications and embodiments thereto. Therefore the present description should be seen as illustrative and not limiting. While the invention is susceptible to various modifications and alternative constructions, it should be understood, that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims.
In any embodiment described herein, the open-ended terms "comprising," "comprises,” and the like (which are synonymous with "including," "having,”and "characterized by") may be replaced by the respective partially closed phrases "consisting essentially of," consists essentially of," and the like or the respective closed phrases "consisting of," "consists of, and the like.
As used herein, the singular forms “a,” “an,” and “the” designate both the singular and the plural, unless expressly stated to designate the singular only.
Gears are used extensively for transmission of power. They find application in automobiles, gear-boxes, oil engines, machine tools, industrial machinery, agricultural machinery, geared motors etc. To meet the strenuous service conditions the gears should have robust construction, reliable performance, high efficiency, economical and long life. Gears should be fatigue free and free from high stresses to avoid their frequent failures. The gear drives should be free from noise, chatter and should ensure high load carrying capacity at constant velocity ratio. To meet all the above conditions, the gear manufacturing has become a highly specialized field.
The present invention relates to apparatus and method for developing starter pinion (gears), adapted for use in vehicle differentials and more particularly to an auto component and a method for manufacturing a starter pinion(gear) localization of a relatively complex configuration using pre-forming and cold forming mechanism and a machine finishing operation to provide a starter pinion localization of high-precision, good fatigue life and good yield.
Figure 1 illustrates a diagrammatic view of the process involved in manufacturing starter pinion localization according to an embodiment of the present invention and steps in the formation of the starter pinion localization comprise steps as follows. Each step depicted in the aforesaid figure has been explained in the following paragraphs.
The method for manufacturing a starter pinion (gear) localization, comprises the steps of ; selecting a piece of a raw material to perform a pre-form operation at an ambient temperature using a suitable closed die of preferred size; placing at least one said die set on said raw material of step a to form a pinion like structure; forging structure of step b to cold forming operation on cold former KP-250 at an ambient temperature; producing a starter pinion(gear) localization as the desired product having a plurality of net-shaped teeth with forged chamfer on the outer portion of said starter pinion on completion of step c; hardening at least a portion of said net-shaped teeth; and selecting and performing a machine finishing operation for yielding the near finished shape of said product.
The raw material is preferably billets used are usually of made up of steel or alloy materials and alike and plays an important role towards selecting an optimized cold-forming conditions and thereafter performing other supportive operations, depending upon the structural features of the final product, structural strength, functional features of the product etc. A billet is obtained, and the billet used in general forging of gears is rod-shaped metallic material, such as carbon steel, and the rod-shaped metallic material is cut to an appropriate length to serve as the billet 10 waiting to be machined.
Figure 2 illustrates a flow diagram of all the steps involved in the development of the starter pinion localization, wherein said flow diagram is being supported herein by a table and a detailed explanation on the same.
The essential and optional operations towards manufacturing pinion by proposed method herein is shown in following table depicted herein below.
Table 1
No. of Steps: Particular of the step performed during complete manufacturing process:
1 Raw material Receipt
2 Receiving Inspection of Raw Material by QA
3 Pre-Forming
4 Annealing
5 Shot Blasting
6 Phosphating
7 Cold Forming (KP-250)
8 CNC Turning 1
9 CNC Turning 2
10 De Burring
11 Carburising
12 Shot Blasting
13 Bush Fitting
14 Bush & OD Turning
15 Final Inspection (Sampling PDI)

In this proposed method, all the major structural features like central hole as well as complete teeth profile gets created during horizontal hot/warm forging. With proper designing and dimension-selection pertaining to central hole diameter and tooth length/shape/orientation etc.; a suitable closed die is prepared and applied for performing the proposed horizontal hot forging towards preparing the present gear with teeth.
Immediately after performing said forging, to enhance structural strength and other properties of the gear component and to optimize the grain profile of the gear with teeth component, the work piece is subjected to a set of operations, which are annealing, shot blasting and phosphating.
During annealing, the forged work piece is subjected to heat treatment wherein the material of said work piece is altered, causing changes in its properties such as strength and hardness. It is a process that produces conditions by heating to above the recrystallization temperature, maintaining a suitable temperature, and then cooling. Annealing is used to induce ductility, soften material, relieve internal stresses, refine the structure by making it homogeneous, and improve cold working properties.
In shot blasting or abrasive blasting stage, the work piece undergoes smoothening of its rough surface, shaping of the surface and removal of surface contaminants therein. A pressurized fluid, typically air, or a centrifugal wheel is used to propel the media in the operation.
Phosphate coating (phosphating) is a conversion coating consisting of an insoluble crystalline metal-phosphate salt formed in a chemical reaction between the substrate metal and a phosphoric acid solution containing ions of metals (zinc, iron or magnesium).
Apart from above forging process as well as other supportive processes, certain additional gear making processes are performed towards finalizing the gear with teeth component, which are mainly CNC machining, broaching, shaving, case carburizing and shot blasting. These additional steps performed towards making of present gear with teeth further enhance the structural features, performance and life of the gear with teeth component.
Broaching and saving refines and smoothen further the edges and corners of various elevations and depressions created on the gear with teeth component, especially the teeth profile therein. Case hardening or surface hardening is the process of hardening the surface of metal, often low carbon steel, by infusing elements into the material's surface, forming a thin layer of a harder alloy. Case hardening is usually done after the part in question has been formed into its final shape.
Carburizing basically is a heat treatment process in which iron or steel is heated in the presence of another material (in the range of 900 to 950° C. (1,650 to 1,740° F.)) which liberates carbon as it decomposes. Depending on the amount of time and temperature, the affected area can vary in carbon content. Longer carburizing times and higher temperatures lead to greater carbon diffusion into the part as well as increased depth of carbon diffusion. Finally, shot blasting creates a smooth and finished surface to the gear with teeth component.
Although the field of the invention has been described herein with limited 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. An improved method or process for manufacturing a starter pinion (gear), comprises the steps of;
a. selecting a raw material to perform a pre-form operation at an ambient temperature using a suitable closed die of preferred size;
b. placing at least one said die set on said raw material of (step a) to form a pinion like structure;
c. forging structure of (step b) to cold forming operation on cold former KP-250 at an ambient temperature;
d. producing a starter pinion(gear) with forged chamfer localization as the desired product having a plurality of net-shaped teeth on the outer portion of said starter pinion on completion of (step c);
e. hardening at least a portion of said net-shaped teeth; and
f. selecting and performing a machine finishing operation for yielding the near finished shape of said product.
2. An improved method or process for manufacturing a starter pinion (gear) as claimed in Claim 1, wherein said raw material is billet, preferably made up of steel or alloy materials and alike.
3. An improved method or process for manufacturing a starter pinion (gear) as claimed in Claim 1, wherein said starter pinion, comprises of at least 8 net-shaped teeth of variable optional range of desired shape, size, dimension, surface pattern and configuration arranged on the outer section of said pinion.
4. The method or process for manufacturing a starter pinion (gear) as claimed in Claim 1, wherein said machine finishing operation is performed by the CNC machine (case carburizing, shot blasting) for turning the post cold formed product to yield the near finished shape of the desired product.
5. The method or process for manufacturing a starter pinion (gear) as claimed in Claim 1, wherein said method is characterized by structural and functional properties of said manufactured starter pinion with teeth component, mainly in terms of its high stress bearing capacity, corrosion resistance, high temperature tolerance and high structural strength.