FIELD OF THE INVENTION

The present invention generally relates to a honing apparatus or honing tool. More particularly, the present invention relates to a honing apparatus for performing a honing operation on a workpiece with a high precision surface.

DESCRIPTION OF THE RELATED ART

As known, honing is a machining process that produces a precision surface or finish on a workpiece. The precision surface is achieved by scrubbing an abrasive grinding wheel or abrasive grinding stone against the workpiece along a controlled path. Honing is used to improve geometric form or finish of the surface of the workpiece. Depending on the type of geometric form or finish required, a variety of abrasives are used. Examples of the abrasives include particles of silicon carbide, aluminium oxide, diamond, cubic boron nitride, etc. Typically, the abrasives are used with a honing apparatus or honing tool. The honing tools are used manually or with an automatic honing machine to produce desired honed characteristics on the workpiece. The honing tool is supplied with a rotational motion and the honing tool is moved in reciprocating motion by a distance corresponding to the working area of the workpiece for carrying out the honing.

Several honing tools have been proposed in the past, which allow to produce desired honed characteristics on the workpiece. One such honing tool is disclosed in a U.S. granted Pat. No. 5,482,498, entitled “Honing tool and super precision finishing method using the same” (“the '498 patent”). The '498 patent discloses a honing tool for carrying out honing working of a work with high accuracy. The honing tool is mainly constituted by a pilot section (5), a rough grinding section (7), a finish grinding section (10) and a correction section (13). The honing tool is sent at rapid speed while being reciprocated little, and the machining working and correction finishing of the straightness are carried out thereby the honing working is carried out. According to the invention, the machining working efficiency and the working accuracy can be improved, and the honing finishing with high straightness becomes possible.

Another example is disclosed in a United States Publication No. 20020173236, entitled “Honing method” (“the '236 Publication”). The '236 Publication discloses a honing method using an arbor honing tool a remachining be carried out using the same tool either simultaneously or following onto arbor honing, in which the ratio of the stroke speed to the rotational speed of the tool is significantly increased. This leads to a cross-structure of the honing tracks allowing a better oil holding capacity.

Although the disclosures presented above are useful in carrying out honing of the workpiece with high accuracy, they have several problems. For instance, the existing honing tools require multiple passes (reciprocating motions and rotational motions) to perform the honing operation. The existing honing tools remove a stock of material according to the grit of diamonds being plated on the tool. As a result, a single pass (reciprocal cycle/stroke) produces the surface finish according to the grit being implied to the tool. In addition, traditional diamond plated tools would require four different honing tools to remove similar stock of material and desired surface finish. As such, the traditional diamond plated tools require changing multiple tools and consumes time.

Further, the traditional diamond plated tool has no provision to align the tool in the axis of the component. The traditional diamond plated tool uses a steel shank with an adjustable cast iron split zone which is diamond plated. As such, the traditional diamond plated tool requires manual realignment of the machine spindle relative to the workpiece or repositioning the workpiece relative to the machine spindle. Such repositioning is generally impractical. Further, manual realignment or repositioning the workpiece is time consuming, and expensive. Further, there is a risk of the steel shank twisting and bending over time.

Therefore, there is a need in the art to provide a honing apparatus that can provide a surface finish better than the traditional honing tools, requiring lesser time and avoiding use of different diamond plated tools.

SUMMARY

It is one of the main objects of the present invention to provide a honing apparatus for producing a precision surface on a workpiece and that avoids the drawbacks of the prior art.

It is another object of the present invention to provide a honing apparatus or honing tool that provides a surface finish better than the previous honing tools.

It is another object of the present invention to provide a honing apparatus that achieves a much higher surface finish with a single tool instead of multiple different diamond plated tools as in the prior art.

In order to overcome the limitations here stated, the present invention provides a honing apparatus for producing a precision surface on a workpiece. The honing apparatus includes a shank having a first zone, a second zone and a third zone. The first zone positions at substantially proximity to a distal end of the shank. The second zone positions at substantially centre of the shank. The third zone positions adjacent to the second zone. The honing apparatus includes a centering section positioned at the distal end of the shank. The first zone has a larger diameter than the centering section. The second zone has a larger diameter than the first zone. The third zone has a larger diameter than the second zone.

Further, the first zone has a rough honing zone with a rough grit diamond. The second zone has a semi-finish honing zone with a medium grit diamond. The third zone has a final-finish honing zone with a fine grit diamond. Further, the second zone has a larger diameter than the first zone. The third zone has a larger diameter than the second zone.

The shank connects to a honing machine via an adapter. The honing machine is configured to operate at a desired oscillation/pecking cycle. In operation, the shank axially advances towards an area on a workpiece to be precision surfaced, while rotating and reciprocating relative to the workpiece to be precision surfaced. The centering section centers and aligns the shank at the workpiece such that the workpiece comes in contact with the first zone followed by the second zone and the third zone. The first zone, the second zone and the third zone remove a stock of material from the workpiece for precision surface on the workpiece.

In one advantageous feature of the present invention, the first zone removes approximately 0.1 millimetre of stock of material. The second zone removes approximately 0.02 millimetre of stock of material. The third zone removes approximately 0.0006-0.0013 millimetre of stock of material.

In another advantageous feature of the present invention, the honing apparatus produces a much higher surface finish through a unique adjustable oscillation/pecking cycle.

In another advantageous feature of the present invention, the honing apparatus is made of a carbide material, which is known to be the hardest material for maintaining straightness and long life. The honing apparatus having the centering section and honing zones are conditioned to the exact size for providing finish honing. In other words, the centering provides guide alignment and helps the honing zones conditioned to the exact size for providing finish honing. This ensures the users need not have to do any adjustment.

In yet another advantageous feature of the present invention, the honing apparatus presents a fast and accurate method of sizing certain bores to final size with high precision.

In yet another advantageous feature of the present invention, the size of zones is fixed depending on the workpiece and/or the honing operation to be performed. Further, the outer diameter of the honing apparatus is conditioned to higher limits to perform thousands of honing operations. If needed, the honing apparatus is conditioned to hone at lower limits by replacing or replating the honing apparatus.

Features and advantages of the invention hereof will become more apparent in light of the following detailed description of selected embodiments, as illustrated in the accompanying FIGUREs. As will be realized, the invention disclosed is capable of modifications in various respects, all without departing from the scope of the invention. Accordingly, the drawings and the description are to be regarded as illustrative in nature.

BRIEF DESCRIPTION OF THE DRAWINGS

With the above and other related objects in view, the invention consists in the details of construction and combination of parts as will be more fully understood from the following description, when read in conjunction with the accompanying drawings in which:

FIG. 1 illustrates an environment in which a honing apparatus implements, in accordance with one embodiment of the present invention; and

FIG. 2 illustrates the honing apparatus, in accordance with one embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

The following detailed description set forth below in connection with the appended drawings is intended as a description of exemplary embodiments in which the presently disclosed invention may be practiced. The term “exemplary” used throughout this description means “serving as an example, instance, or illustration,” and should not necessarily be construed as preferred or advantageous over other embodiments. The detailed description includes specific details for providing a thorough understanding of the presently disclosed honing apparatus. However, it will be apparent to those skilled in the art that the presently disclosed invention may be practiced without these specific details. In some instances, well-known structures and devices are shown in functional or conceptual diagram form in order to avoid obscuring the concepts of the presently disclosed honing apparatus.

In the present specification, an embodiment showing a singular component should not be considered limiting. Rather, the invention preferably encompasses other embodiments including a plurality of the same component, and vice-versa, unless explicitly stated otherwise herein. Moreover, the applicant does not intend for any term in the specification to be ascribed an uncommon or special meaning unless explicitly set forth as such. Further, the present invention encompasses present and future known equivalents to the known components referred to herein by way of illustration.

Although the present invention provides a description of a honing apparatus, it is to be further understood that numerous changes may arise in the details of the embodiments of the apparatus. It is contemplated that all such changes and additional embodiments are within the spirit and true scope of this disclosure.

The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure.

The present invention discloses a honing apparatus for producing a precision surface on a workpiece. The honing apparatus includes a shank having a first zone positioned at substantially proximity to a distal end of the shank and a second zone positioned at substantially centre of said shank. The first zone has a rough grit diamond than the second zone. The honing apparatus includes a centering section positioned at the distal end of the shank. The shank connects to a honing machine via an adapter. The shank axially advances towards an area on a workpiece to be precision finished, while rotating and reciprocating relative to the workpiece to be precision surfaced. The centering section centers and aligns the shank at the workpiece such that the workpiece comes in contact with the first zone followed by the second zone. The first zone and the second zone remove a stock of material from the workpiece for precision surface on the workpiece.

Various features and embodiments of a honing apparatus for producing a precision surface on a workpiece are explained in conjunction with the description of FIGS. 1-2.

Referring to FIG. 1, an environment 10 in which a honing apparatus or honing tool 12 implements is shown, in accordance with one embodiment of the present invention. Honing apparatus 12 is used in a honing machine 14. An example of honing machine 14 includes, but not limited to, a valve guide honing machine, a cylindrical block honing machine, etc. Honing machine 14 includes a housing 16 for receiving honing apparatus 12. In the present invention, honing apparatus 12 performs a honing operation on a workpiece 18 with high precision surface. An example of workpiece 18 includes, but not limited to, an internal combustion engine, an air-bearing spindle, cylinder, a gear, glass panel, etc.

FIG. 2 shows honing apparatus 12, in accordance with one embodiment of the present invention. Honing apparatus 12 includes a first end 20 and a second end 22. Honing apparatus 12 includes an adapter 24. Adapter 24 connects to housing 16 of honing machine 14 and helps to operate honing apparatus 12 in reciprocal and rotational motions for performing honing operations on workpiece 18. Honing apparatus 12 includes a shank or cylindrical body or arbor 26. Shank 26 comes in a cylindrical configuration. In one example, shank 26 has a tapered configuration. A person skilled in the art understands that shank 26 can have a single taper or multiple tapers at one or both ends depending on the need. Shank 26 is made of a suitable material such as a premium grade carbide material or hardened or unhardened steel. Shank 26 includes a head or headstock 28 that connects to an adapter 24.

At second end, shank 20 encompasses a centering section 30. Centering section 30 has a tapered configuration extending from a cylindrical configuration with smooth surface. Centering section 30 acts as a centering and aligning section for honing apparatus 12. Centering section 30 helps to align shank 26 at center and hone workpiece 18.

Further, shank 20 includes a first zone 32, a second zone 40 and a third zone 48. First zone 32, second zone 40 and third zone 48 are spaced apart. First zone 32 positions adjacent to centering section 30. Second zone 40 positions adjacent to first zone 32. Further, third zone 48 positions adjacent to second zone 40. In one example, each of first zone 32, second zone 40 and third zone 48 consists of a diamond abrasive boring bar which is constructed from an expandable soft cast iron sleeve permanently coated with grit of natural diamond abrasive or constructed with a sintered sleeve which has abrasive embedded in it. In accordance with the present invention, first zone 32 presents a rough honing zone or rough honing section having rough grit diamond. Second zone 40 presents a semi-finish honing zone or medium honing section with a medium grit diamond. Third zone 48 presents a final finish honing zone or fine honing section with a fine grit diamond.

In one implementation, first zone 32 is integrated with shank 26. In another implementation, first zone 32 is provided as a sleeve or plate over shank 26. First zone 32 is made of natural and synthetic diamonds, premium grade carbide material or hardened or unhardened steel, cubic boron nitrides, and superabrasives, of appropriate hardness, friability, compatibility and other characteristics for particular applications. First zone 32 includes a first tapered section 34, a first section 36 and a second tapered section 38. First tapered section 34 is tapered inwards/towards shank 26. In one example, first tapered section 34 is tapered to align with the outer diameter of centering section 30. First section 36 has a substantially cylindrical configuration and has a slightly larger diameter than centering section 30. Second tapered section 38 extends from first section 36 and tapers inwards/towards shank 26.

Shank 20 includes a second zone 40 positioned adjacent to first zone 32. In one implementation, second zone 40 is integrated with shank 26. In another implementation, second zone 40 is provided as a sleeve or plate over shank 26. Second zone 40 is made of natural and synthetic diamonds, premium grade carbide material or hardened or unhardened steel, cubic boron nitrides, and superabrasives, of appropriate hardness, friability, compatibility and other characteristics for particular applications. Second zone 40 includes a third tapered section 42, a second section 44 and a fourth tapered section 46. Third tapered section 42 is tapered inwards/towards shank 26. In one example, third tapered section 42 is tapered to align with the outer diameter of first section 36 of first zone 32. Second section 44 has a substantially cylindrical/straight configuration and has a slightly larger diameter than first section 36. Fourth tapered section 46 extends from second section 44 and tapers inwards/towards shank 26.

Shank 20 includes a third zone 48 positioned adjacent to second zone 40. In one implementation, third zone 48 is integrated with shank 26. In another implementation, third zone 48 is provided as a sleeve or plate over shank 26. Third zone 48 is made of natural and synthetic diamonds, premium grade carbide material or hardened or unhardened steel, cubic boron nitrides, and superabrasives, of appropriate hardness, friability, compatibility and other characteristics for particular applications. Third zone 48 includes a fifth tapered section 50, a third section 52 and a sixth tapered section 54. Fifth tapered section 50 is tapered inwards/towards shank 26. In one example, fifth tapered section 50 is tapered to align with the outer diameter of second section 44 of second zone 40. Third section 52 has a substantially cylindrical/straight configuration and has a slightly larger diameter than second section 44 of second zone 40. Sixth tapered section 54 extends from third section 52 and tapers inwards/towards shank 26.

In one embodiment, the diameter of centering section 30 is approximately 0.11 millimetres less than the diameter of third zone 48 to obtain the required finishing. Each of first zone 32, second zone 40 and third zone 48 has an incremental diameter with respect to centering section 30. The incremental diameter helps to obtain required centering and surface finish when first zone 32, second zone 40 and third zone 48 come in contact with workpiece 18. In one example, first zone 32, second zone 40 and third zone 48 are provided with an incremental diameter of say 0.1 or 0.01 millimetre than centering section 30. First zone 32, second zone 40 and third zone 48 are provided with incremental diameter to achieve greater or near zero alignment of honing apparatus 12 and workpiece 18.

In accordance with the present invention, second end 22 of honing apparatus 12 faces workpiece 18. As specified above, honing apparatus 12 connects to housing 16 of honing machine 14. Honing machine 14 operates based on manual operation or automatically based on the preconfigured settings. In one example, honing machine 14 operates honing apparatus 12 based on a predetermined oscillation/pecking cycle depending on the precision surface required on workpiece 18. Honing machine 14 operates honing apparatus 12 to advance axially towards an area on workpiece 18 to be precision surfaced/finished. Here, honing apparatus 12 is made to rotate and reciprocate relative to workpiece 18 to be precision surfaced. In other words, honing apparatus 12 is driven in a rotational motion and is moved in reciprocating motion by a distance corresponding to the working area of workpiece 18 for carrying out the honing. In one example, honing apparatus 12 advances 5 millimetres in the direction of second end 22 and withdraws 5 millimetres in the direction of first end 20. The speed and the depth at which honing apparatus 12 advances is pre-programmed at honing machine 14 depending on the type of material, hardness of material of workpiece 18, grit of zones and the surface finish needed.

At first, centering section 30 comes in contact with workpiece 18. In one example, centering section 30 has a slightly less diameter say about 110 microns or 0.11 millimetre than workpiece or guide valve 18. Workpiece 18 aligns with centering section 30. As shank 26 axially advances, first tapered section 34 of first zone 30 comes in contact with workpiece 18. As specified above, first tapered section 34 is tapered, as such any alignment that is missed at centering section 30 gets compensated at first tapered section 34. This ensures honing apparatus 12 is centered.

After workpiece 18 gets aligned, first section 36 comes in contact with workpiece 18. At this point, honing apparatus 12 is in axis with workpiece 18. As honing apparatus 12 advances into workpiece 18, first section 36 removes a stock of material from workpiece 18. As specified above, first section 36 (of first zone 32) has a rough grit diamond. As such, first section 36 removes the stock of material. In one example, first zone 32 has a US Mesh (FEPA) size of 60/80 (D252) to remove the stock of material. The removed stock of material passes through second tapered section 38. Subsequently, workpiece 18 comes in contact with third tapered section 42. Optionally, if first zone 32 is too small, the alignment happens with the help of third tapered section 42 at second zone 40. As honing apparatus 12 advances into workpiece 18, second section 44 removes a stock of material from workpiece 18. As specified above, second section 44 has a medium grit diamond. In one example, second zone 40 has a US Mesh (FEPA) size of 80/100 (D181) to remove the stock of material. The removed stock of material passes through fourth tapered section 46. Subsequently, workpiece 18 comes in contact with fifth tapered section 50 of third zone 48. As honing apparatus 12 advances into workpiece 18, third section 52 removes a stock of material from workpiece 18. As specified above, third section 52 has a fine grit diamond. In one example, third zone 48 has a US Mesh (FEPA) size of 100/120 (D151) to remove the stock of material.

In one exemplary implementation, first section 36 removes approximately 0.1 millimetres of stock of material from workpiece 18. Second section 44 removes approximately 0.01 millimetres of stock of material from workpiece 18. Third section 50 removes approximately 0.002 millimetres or even 0.0006-0.0013 millimetres of stock of material from workpiece 18. As such, the presently disclosed honing apparatus 12 can be used to obtain surface finishing ranging from 0.002 millimetres to 0.1 millimetres. Optionally, honing apparatus 12 produces a surface finish ranging from 0.03 millimetres up to 0.0006-0.0013 millimetres using a variety of grit sizes. The grit size on each of first zone 32, second zone 40 and third zone 48 is selected based on the material and material hardness of workpiece 18 and the surface finish to be produced.

A person skilled in the art understands that honing apparatus 12 removes material approximately 0.1 millimetre with a final surface finish of approximately 0.0006-0.0013 millimetres. The precision surface together with guide alignment with the help of centering section 36 presents a unique adjustable oscillation/pecking cycle that produces surface finish. This enables honing apparatus 12 to precision surface (Nano precision ground) and condition to exact diameter to hone.

It should be understood that the honing apparatus presents a fast and accurate method of sizing certain bores to final size i.e., fine grit (final finishing zone). The super abrasive zones mounted on the shank/arbor are expandable. For instance, the zone(s) is expanded to size during the setup. Further, the shank is pushed through the bore only once. If required, only periodic expansion adjustments are necessary to compensate for tool wear after initial setup. The honing apparatus is used depending on the types and volumes of material that can be removed. The size and volume of chips removed should be no more than there is clearance between the grit diamonds on the zone. Therefore, the presently disclosed honing apparatus is best suited for honing operations that produce a relatively low volume of chips, such as interrupted or short bores, and is most successful in honing cast iron and powdered metals.

Although the above description is explained considering that there are three different zones of varied grit size, it is possible to implement the invention with two zones such as first zone 32 and second zone 40. In such implementation, first zone 32 includes a US Mesh (FEPA) size of 60/80 (D252) to remove a majority of stock of material. Further, second zone 40 has a US Mesh (FEPA) size of 100/120 (D151) to remove the stock of material and provide precision surface. Such an implementation falls within the scope of the present invention.

The present invention provides several advantages over the prior art. The presently disclosed shank is made of carbide material, which is known to be the hardest material for maintaining straightness and long life. The tool is conditioned to the exact size for providing finish honing together with alignment of the workpiece. This ensures the users need not have to do any adjustment prior or during the operation of the honing apparatus. Further, the presently disclosed honing apparatus having a fine grit (final finishing zone) is capable of removing approximately 0.0006-0.0013 millimetres of material. This provides a much prevision surface with a single tool when compared to prior art which require up to 4 tools to achieve the same finishing.

A person skilled in the art appreciates that the honing apparatus may come in a variety of shapes and sizes depending on the need and comfort of the user. Further, many changes in the design and placement of components may take place without deviating from the scope of the presently disclosed honing apparatus.

In the above description, numerous specific details are set forth such as examples of some embodiments, specific components, devices, methods, in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to a person of ordinary skill in the art that these specific details need not be employed, and should not be construed to limit the scope of the invention.

In the development of any actual implementation, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as compliance with system-related and business-related constraints. Such a development effort might be complex and time-consuming, but may nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill. Hence as various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

The foregoing description of embodiments is provided to enable any person skilled in the art to make and use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the novel principles and invention disclosed herein may be applied to other embodiments without the use of the innovative faculty. It is contemplated that additional embodiments are within the spirit and true scope of the disclosed invention.