DESC:FIELD OF THE DISCLOSURE
The present invention relates to micro-finishing tools, particularly to the micro-finishing tools for worm shafts.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
Average Surface Roughness (Ra): The term ‘Average Surface Roughness’ and the abbreviation ‘Ra’ mentioned herein in the disclosure refers to the arithmetic mean of the absolute surface height deviations from the mean line, calculated over a specified length. It provides a general measure of surface roughness but does not account for extreme peaks or valleys.
Mean Roughness Depth (Rz): The term ‘Mean Roughness Depth’ and the abbreviation ‘Rz’ mentioned herein in the disclosure refer to the average height difference between the highest peak and the lowest valley across five sampling lengths within an evaluation length. It offers a more detailed assessment of surface texture by reflecting significant height variations.
Maximum Profile Peak Height (Rp): The term ‘Maximum Profile Peak Height’ and the abbreviation ‘Rp’ mentioned herein in the disclosure refer to the height of the tallest peak above the mean line within a specified evaluation length. It is crucial for applications where high peaks could lead to wear or damage in interacting surfaces.
Maximum Profile Valley Depth (Rv): The term ‘Maximum Profile Valley Depth’ and the abbreviation ‘Rv’ mentioned herein in the disclosure refer to the depth of the deepest valley below the mean line within the evaluation length. This parameter is important in applications where deep valleys might trap debris or fluids, impacting performance.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Worm shafts are essential components in various mechanical and automotive applications, including gearboxes, steering systems, and power transmission devices. These shafts, which feature helical threads, are primarily responsible for transferring motion and torque in systems where precision, durability, and smooth operation are critical. Given the functional importance of worm shafts, their surface finish directly affects the overall performance of the mechanisms they are integrated into.
Traditional techniques for finishing worm shafts, such as grinding or honing, which provide a general level of refinement but are often insufficient for achieving the exacting surface finishes required in modern, high-efficiency systems. However, it has been observed that these traditional techniques are often inadequate in achieving the desired level of surface smoothness on worm shafts, particularly when it comes to reducing the surface roughness below 0.1 microns.
Challenges such as maintaining the correct geometry of the worm shaft during the micro-finishing process, avoiding thread deformation, and achieving uniform surface quality across the entire length of the shaft, have highlighted the limitations of existing finishing tools and processes. As a result, there is a growing demand for tools that can perform precision micro-finishing on worm shafts with greater accuracy and efficiency, while also being adaptable to different shaft sizes and thread profiles.
There is therefore felt a need of a tool for micro-finishing a worm shaft that alleviates the aforementioned drawbacks.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to provide a tool for micro-finishing worm shafts.
Another object of the present disclosure is to provide a tool for micro-finishing worm shafts with improved accuracy and efficiency.
Still, another object of the present disclosure is to achieve a surface roughness of less than 0.1 microns on worm shafts.
Another object of the present disclosure is to develop a micro-finishing tool that preserves the correct geometry of the worm shaft during the finishing process.
Yet another object of the present disclosure is to avoid thread deformation during the micro-finishing process of the worm shaft.
Still, another object of the present disclosure is to ensure uniform surface quality across the entire length of the worm shaft.
Yet another object of the present disclosure is to offer a tool adaptable to different worm shaft sizes and thread profiles.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present invention discloses a tool for micro-finishing a worm shaft, the tool comprises of a linearly displaceable tool post, a chuck, an abrasive film and a shoe. The linearly displaceable tool post is mounted on a motorized manoeuvrable platform. The chuck is configured to removably mount and angularly displace the worm shaft. The abrasive film is configured to be indexed on the worm shaft in an operative configuration of the tool by means of an indexing mechanism. The shoe is configured to be removably mounted on the linearly displaceable tool post and further configured to have an operative surface with a set of internal threads complementary to the threads of the worm shaft. The chuck is configured to angularly displace the worm shaft by a first predetermined angle in a first direction causing the shoe to be linearly displaced from a first position to a second position by a predetermined distance, and the chuck is configured to angularly displace the worm shaft by a second predetermined angle in a second direction causing the shoe to be linearly displaced from the second position back to the first position such that the angular displacement by the chuck and the linear displacement by the shoe is performed in a synchronized and simultaneous manner. The worm shaft is micro-finished by the means of frictional forces generated between the shoe, the abrasive film and the worm shaft.
In an embodiment, the shoe is made of hardened polyurethane.
In an embodiment, the shoe has hardness in the range of 80 to 90 Shores.
In an embodiment, the indexing mechanism comprises a series of instructions that govern the indexing and positioning of the abrasive film, based on parameters including film speed, contact pressure, film tension, indexing increment, wear rate, alignment accuracy, operating temperature, lubrication requirements, cycle time, and number of oscillations.
In an embodiment, the abrasive film is made of aluminium oxide.
In an embodiment, the abrasive film is configured to wind over a reel positioned in proximity to said shoe.
In an embodiment, the chuck is configured to angularly displace the worm shaft in a first direction by rotating the worm shaft 180° in a clockwise direction, and in a second direction by rotating the worm shaft 180° in an anticlockwise direction, thereby returning the worm shaft from the second position to the first position.
In an embodiment, the shoe is configured to be displaced by a distance equivalent to at least three thread pitches, when moving from first position to second position.
In an embodiment, the tool further comprises an automated lubrication system configured to periodically apply lubricant to the worm shaft and the abrasive film in order to reduce friction during micro-finishing operation.
The present disclosure also envisages a method for micro-finishing a worm shaft using a tool. The method comprises the following steps:
• mounting, a linearly displaceable tool post, on a motorized manoeuvrable platform;
• removably mounting and angularly displacing, the worm shaft by a chuck;
• indexing, an abrasive film on the worm shaft in an operative configuration of the tool by the means of an indexing mechanism;
• mounting, a shoe configured to have an operative surface with a set of internal threads complementary to the threads of the worm shaft, on a linearly displaceable tool post;
• angularly displacing, the worm shaft by a first predetermined angle in a first direction using the chuck,;
• linearly displacing the shoe from a first position to a second position by a predetermined distance using the tool post;
• angularly displacing the worm shaft by a second predetermined angle in a second direction using the chuck;
• linearly displacing the shoe from the second position back to the first position using the tool post; and
• micro-finishing, said worm shaft to a desired roughness by the means of frictional forces generated between said shoe, said abrasive film and said worm shaft.
In an embodiment, an initial step before commencing the method for micro-finishing the worm shaft, the shoe is linearly displaced on the worm shaft mounted on the chuck after the abrasive film is indexed on the threads of said worm shaft to press said abrasive film on the threads of said worm shaft.
In an embodiment, the surface roughness of the micro-finished worm shaft is directly proportional to the number of oscillations of the chuck.
In an embodiment, the method further includes a step of increasing the number of oscillations of the chuck to refine the micro-finishing of said worm shaft threads.
In an embodiment, the chuck is configured to angularly displace said worm shaft at a rate of 75 oscillations per minute (OSM).
In an embodiment, the tool is configured to reduce average surface roughness (Ra) of said worm shaft to a value of 0.05 to 0.07 microns after 90 seconds of operation with 180 oscillations.
In an embodiment, the tool is configured to reduce the roughness parameters of the worm shaft, including Ra, Rz, Rp, and Rv, by more than 70% compared to their initial values.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
A tool, of the present disclosure, for micro-finishing a worm shaft will now be described with the help of the accompanying drawings, in which:
Figure 1A illustrates a front view of the tool, in accordance with a preferred embodiment of the present disclosure;
Figure 1B illustrates a side view of the tool of Figure 1A;
Figure 2 illustrates a front view of a shoe, of the tool of Figure 1A, displaced in an operative extreme right direction and a worm shaft angularly displaced in clock-wise direction;
Figure 3 illustrates a front view of the shoe, of the tool of Figure 1A, displaced in an operative extreme left direction and a worm shaft angularly displaced in clock-wise direction;
Figure 4 illustrates a summative front view of the tool, of the tool of Figures 2 and 3;
Figure 5A illustrates a front view of the shoe of Figure 1;
Figure 5B illustrates a front view of the abrasive film of Figure 1; and
Figures 6A, through 6C illustrate graphical representations of the minimum amount, the maximum amount and the average amount of roughness achieved by micro-finishing the worm shaft by the tool of Figure 1.
Figures 7A and 7B illustrate the method (200) for micro-finishing a worm shaft (10) by a tool (100).
LIST OF REFERENCE NUMERALS
10 worm shaft
100 tool for micro-finishing a worm shaft
30 motorized manoeuvrable platform
105 shoe
107 internal threads on the shoe
110 abrasive film
120 chuck
130 tool post
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises”, “comprising”, “including”, “includes” and “having” are open-ended transitional phrases and therefore specify the presence of stated features, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof.
Worm shafts are integral components in mechanical and automotive applications, particularly in gearboxes, steering systems, and power transmission, where precision and durability are paramount. Characterized by their helical threads, these shafts efficiently transfer motion and torque, with surface finish quality significantly impacting performance. Traditional finishing methods, such as grinding and honing, often fail to achieve the requisite surface smoothness below 0.1 microns, which is critical for contemporary systems. A major challenge in the refinement process is maintaining correct geometry while achieving a uniformly smooth surface, as traditional techniques can lead to thread deformation and surface inconsistencies along the shaft length, highlighting their limitations.
To address the issues of the existing systems and methods, the present disclosure envisages a tool for micro-finishing a worm shaft (hereinafter referred to as “tool 100”) in accordance with one embodiment of the disclosure and method for micro-finishing a worm shaft (10) by a tool (100) (hereinafter referred to as “method 200”) in accordance with another embodiment of the disclosure. The tool (100) will now be described with reference to Figure 1 through Figure 6C and the method (200) will be described with reference to Figure 7A and Figure 7B.
Figure 1A illustrates a front view of the tool and Figure 1B illustrates side view of the tool. Referring to figures 1A and 1B the tool (100) for micro-finishing threads on a worm shaft (10) comprises a linearly displaceable tool post (130), a motorized manoeuvrable platform (30), a chuck (120), an abrasive film (110), an indexing mechanism, and a shoe (105), along with internal threads (107) on the shoe (105). The linearly displaceable tool post (130) is mounted on a motorized manoeuvrable platform (30) (not shown) configured to enable controlled linear movement along the axis parallel to the axis of the worm shaft (10). The chuck (120) is configured to hold the worm shaft (10) and enable angular displacement of the worm shaft (10).
The tool post (130) can be moved along a parallel horizontal axis in alignment with the longitudinal axis of the worm shaft (10), allowing the tool to finish the entire length of the threaded surface. The movement is controlled through a programmable controller that can be preset based on the required linear displacement, thread pitch, and the desired level of surface finishing.
The chuck (120) is configured for holding and angularly displacing the worm shaft (10). The chuck (120) is capable of rotating the worm shaft (10) by predetermined angles in both clockwise and anticlockwise directions.
Figure 2 illustrates a front view of a shoe, of the tool of Figure 1A, displaced in an operative extreme right direction and a worm shaft angularly displaced in clock-wise direction. The chuck (120) rotates the worm shaft (10) in a first direction, preferably 180 degrees clockwise. This rotation causes the tool post (130) and the shoe (105) to be linearly displaced along the threads of the worm shaft.
Figure 3 illustrates a front view of the shoe, of the tool of Figure 1A, displaced in an operative extreme left direction and a worm shaft angularly displaced in clock-wise direction. The chuck (120) then rotates the worm shaft (10) in the opposite direction (anticlockwise) by a predetermined angle, typically 180 degrees, to return the worm shaft (10) and shoe (105) to their original positions.
This synchronized angular and linear movement allows the entire length of the threads on the worm shaft (10) to be consistently finished. The chuck (120) can be programmed to vary the angular displacement based on thread pitch, surface roughness requirements, and tool wear. Figure 4 illustrates a summative front view of the tool, of the tool of Figures 2 and 3
Figure 5B illustrates a front view of the abrasive film of Figure 1. The abrasive film (110) is made from a flexible material like aluminum oxide, known for its hardness and abrasive properties. The abrasive film (110) is configured to be indexed on the worm shaft (10) by an indexing mechanism. The film is positioned such that it comes into contact with the threads of the worm shaft during the finishing process. The indexing mechanism is configured for controlling the positioning and movement of the abrasive film (110).
The indexing mechanism controls the movement of the abrasive film (110) by automatically feeding new abrasive material into the operative position for every new worm shaft (10) to be finished. The parameters responsible for indexing of the abrasive film (110), include film speed, contact pressure, film tension, and indexing increment. The indexing mechanism is programmable based on these parameters for a specific finishing task. The abrasive film (110) winds over a reel, which is positioned in proximity to the shoe (105).
Figure 5A illustrates a front view of the shoe of Figure 1. The shoe (105) is designed to ensure precise contact with the threads of the worm shaft (10). The shoe (105) is removably mounted on the linearly displaceable tool post (130). The operative surface of the shoe (105) is shaped with internal threads (107) that are complementary to the threads on the worm shaft (10). These internal threads (107) enable the shoe (105) to engage perfectly with the worm shaft’s (10) threads (107), ensuring even pressure and contact across the surface during the micro-finishing process.
The shoe (105) is typically made from a durable material, such as hardened polyurethane, with a hardness in the range of 80 to 90 Shores. This material provides the right balance of flexibility and strength, ensuring that the shoe (105) conforms to the threads of the worm shaft (10) without excessive wear or deformation.
As the chuck (120) rotates the worm shaft (10), the shoe (105) is linearly displaced from a first position to a second position by a predetermined distance, equivalent to at least three thread pitches. The linear displacement of the shoe (105) is synchronized with the angular displacement of the chuck (120), ensuring that the entire surface of the threads is consistently finished.
The tool (100) also includes an automated lubrication system, which periodically applies lubricant to the worm shaft (10) and the abrasive film (110). This reduces the excess frictional forces during the micro-finishing process, preventing overheating and excessive wearing of the components.
Figures 7A and 7B illustrate the steps involved in one embodiment of a method (200) for micro-finishing a worm shaft (10) by a tool (100). The order in which method (200) is described is not intended to be construed as a limitation, and any number of the described method steps may be combined in any order to implement method (200), or an alternative method. The method 200 comprises the following steps:
• At step 202, the method (200) includes the step of mounting, a linearly displaceable tool post (130), on a motorized manoeuvrable platform (30).
• At step 204, the method (200) includes the step of removably mounting and angularly displacing said worm shaft (10) , by a chuck (120).
• At step 206, the method (200) includes the step of indexing, an abrasive film (110) on said worm shaft (10) in an operative configuration of said tool (100) by the means of an indexing mechanism.
• At step 208, the method (200) includes the step of mounting, a shoe (105) configured to have an operative surface with a set of internal threads (107) complementary to the threads of a worm shaft (10), on a linearly displaceable tool post (130).
• At step 210, the method (200) includes the step of angularly displacing, the worm shaft (10) by a first predetermined angle in a first direction using the chuck (120),
• At step 212, the method (200) includes the step of linearly displacing the shoe (105) from a first position to a second position by a predetermined distance using the tool post (130).
• At step 214, the method (200) includes the step of angularly displacing the worm shaft (10) by a second predetermined angle in a second direction using the chuck (120).
• At step 216, the method (200) includes the step of linearly displacing the shoe (105) from the second position back to the first position using the tool post (130).
• At step 218, the method (200) includes the step of micro-finishing, said worm shaft (10) to a desired roughness by the means of frictional forces generated between said shoe (105), said abrasive film (110), and said worm shaft (10).
In one embodiment, the chuck (120) operates at 75 oscillations per minute, and the tool is capable of reducing the average surface roughness (Ra) to 0.05 to 0.07 microns within 90 seconds of operation, involving 180 oscillations.
Table 1 given below shows the roughness achieved after the threads of the worm shaft (10) were micro-finished by the tool (100).
Summary
Time Period Number of Reciprocating strokes Output Average Roughness (Ra) in microns
30 seconds 60 0.15-0.2
60 seconds 120 0.1-0.15
90 seconds 180 0.05-0.07
In another embodiment, the tool (100) provides precise micro-finishing, reducing roughness parameters like Ra, Rz, Rp, and Rv by over 70% compared to the initial values. Figures 6A, through 6C illustrate graphical representations of the minimum amount, the maximum amount and the average amount of roughness achieved by micro-finishing the worm shaft by the tool of Figure 1.
Table 2 given below present the minimum, maximum, and average roughness values of the threads before being micro-finished.
Input Summary
Min. Max. Average
Ra 0.155 0.499 0.297
Rz 1.053 2.837 1.979
Rp 0.418 1.855 1.037
Rv 0.590 1.278 1.005
Table 3 given below present the minimum, maximum and average roughness values of the threads after being micro-finished for a time period of 90 seconds.
Output Summary
Min. Max. Average
Ra 0.048 0.109 0.077
Rz 0.300 0.783 0.550
Rp 0.135 0.309 0.223
Rv 0.160 0.503 0.327

In a preferred embodiment, in an initial step before commencing the method (200) for micro-finishing the threads, the shoe (105) is linearly displaced on the worm shaft (10) mounted on the chuck (120) after the abrasive film (110) is indexed on the threads of said worm shaft (10) to press said abrasive film (110) on the threads of said worm shaft (10).
In another embodiment, the surface roughness of the micro-finished worm shaft (10) is directly proportional to the number of oscillations of the chuck (120).
In another embodiment, the number of oscillations of the chuck (120) can be increased to refine the micro-finishing of said worm shaft (10) threads.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described hereinabove has several technical advantages including, but not limited to, the realization of a tool for micro-finishing a worm shaft, which:
• is capable of providing improved accuracy and efficiency for micro-finishing worm shafts;
• is designed to achieve a surface roughness of less than 0.1 microns on worm shafts;
• is designed to preserve the original thread geometry of the worm shaft during the micro-finishing process;
• is effective in avoiding thread deformation during the micro-finishing of the worm shaft;
• is able to ensure uniform surface quality along the entire length of the worm shaft; and
• is adaptable to various worm shaft sizes and thread profiles for flexible use across different applications.
The foregoing disclosure has been described with reference to the accompanying embodiments which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Any discussion of materials, implants, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:WE CLAIM:
1. A tool (100) for micro-finishing a worm shaft (10), said tool (100) comprising:
• a linearly displaceable tool post (130) mounted on a motorized manoeuvrable platform (30);
• a chuck (120) configured to removably mount and angularly displace said worm shaft (10);
• an abrasive film (110) configured to be indexed on said worm shaft (10) in an operative configuration of said tool (100) by means of an indexing mechanism; and
• a shoe (105) configured to be removably mounted on said linearly displaceable tool post (130) and further configured to have an operative surface with a set of internal threads (107) complementary to the threads of said worm shaft (10);
wherein said chuck (120) is configured to angularly displace said worm shaft (10) by a first predetermined angle in a first direction causing said shoe (105) to be linearly displaced from a first position to a second position by a predetermined distance, and said chuck (120) is configured to angularly displace the worm shaft (10) by a second predetermined angle in a second direction causing said shoe (105) to be linearly displaced from said second position back to said first position such that the angular displacement by said chuck (120) and the linear displacement by said shoe (105) is performed in a synchronized and simultaneous manner;
wherein the said worm shaft (10) is micro-finished by the means of frictional forces generated between said shoe (105), said abrasive film (110) and said worm shaft (10).
2. The tool (100) as claimed in claim 1, wherein said shoe (105) is made of hardened polyurethane.
3. The tool (100) as claimed in claim 1, wherein said shoe (105) has hardness in the range of 80 to 90 Shores.
4. The tool (100) as claimed in claim 1, wherein the indexing mechanism comprises a series of instructions that govern the indexing and positioning of the abrasive film (110), based on parameters including film speed, contact pressure, film tension, indexing increment, wear rate, alignment accuracy, operating temperature, lubrication requirements, cycle time, and number of oscillations.
5. The tool (100) as claimed in claim 1, wherein said abrasive film (110) is made of aluminium oxide.
6. The tool (100) as claimed in claim 1, wherein said abrasive film (110) is configured to wind over a reel positioned in proximity to said shoe (105).
7. The tool (100) as claimed in claim 1, wherein said chuck (120) is configured to angularly displace said worm shaft (10) in a first direction by rotating said worm shaft (10) 180° in a clockwise direction, and in a second direction by rotating said worm shaft (10) 180° in an anti-clockwise direction, thereby returning said worm shaft (10) from the second position to the first position.
8. The tool (100) as claimed in claim 1, wherein said shoe (105) is configured to be displaced by a distance equivalent to at least three thread pitches, when moving from first position to second position.
9. The tool (100) as claimed in claim 1, wherein said tool (100) further comprises an automated lubrication system configured to periodically apply lubricant to said worm shaft (10) and said abrasive film (110) in order to reduce friction during micro-finishing operation.
10. A method (200) for micro-finishing a worm shaft (10) by a tool (100), said method (200) comprises the following steps:
• mounting, a linearly displaceable tool post (130), on a motorized manoeuvrable platform (30);
• removably mounting and angularly displacing said worm shaft (10) by a chuck (120);
• indexing, an abrasive film (110) on said worm shaft (10) in an operative configuration of said tool (100) by the means of an indexing mechanism;
• mounting, a shoe (105) configured to have an operative surface with a set of internal threads (107) complementary to the threads of a worm shaft (10), on a linearly displaceable tool post (130);
• angularly displacing, the worm shaft (10) by a first predetermined angle in a first direction using the chuck (120);
• linearly displacing the shoe (105) from a first position to a second position by a predetermined distance using the tool post (130);
• angularly displacing the worm shaft (10) by a second predetermined angle in a second direction using the chuck (120);
• linearly displacing the shoe (105) from the second position back to the first position using the tool post (130); and
• micro-finishing, said worm shaft (10) to a desired roughness by the means of frictional forces generated between said shoe (105), said abrasive film (110) and said worm shaft (10).
11. The method (200) as claimed in claim 10, wherein in an initial step before commencing the method (200) for micro-finishing the threads, the shoe (105) is linearly displaced on the worm shaft (10) mounted on the chuck (120) after the abrasive film (110) is indexed on the threads of said worm shaft (10) to press said abrasive film (110) on the threads of said worm shaft (10).
12. The method (200) as claimed in claim 10, wherein the surface roughness of the micro-finished worm shaft (10) is directly proportional to the number of oscillations of the chuck (120).
13. The method (200) as claimed in claim 10, wherein said method (200) further includes a step of increasing the number of oscillations of the chuck (120) to refine the micro-finishing of said worm shaft (10) threads.
14. The method (200) as claimed in claim 10, wherein said chuck (120) is configured to angularly displace said worm shaft (10) at a rate of 75 oscillations per minute (OSM).
15. The method (200) as claimed in claim 10, wherein said tool (100) is configured to reduce average surface roughness (Ra) of said worm shaft (10) to a value of 0.05 to 0.07 microns after 90 seconds of operation with 180 oscillations.
16. The method (200) as claimed in claim 10, wherein said tool (100) is configured to reduce the roughness parameters of the worm shaft (10), including Ra, Rz, Rp, and Rv, by more than 70% compared to their initial values.

Dated this 14th day of October 2024

_______________________________
MOHAN RAJKUMAR DEWAN
OF R.K.DEWAN & CO.
AUTHORIZED AGENT OF APPLICANT