The present disclosure relates to honing devices and more particularly to single honing tools and tandem honing devices which provide improved control and accuracy of the honing process.
The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Honing is generally defined as an abrasive machining process that produces a precision surface on a metal workpiece. It is most generally utilized to provide a smooth, dimensionally accurate finish on internal cylindrical surfaces such as the cylinder walls of internal combustion engines. This is achieved by moving one or more abrasive stones or hones on or over the surface of the workpiece, typically by simultaneously rotating the hones and translating (oscillating) them axially.
While the process is related to and often compared to grinding, the basic nature of the process renders it most suitable for precision final treatment of metal workpieces such as, as noted above, cylinders and similar bores. This precision is the result of the simultaneous rotation and axial oscillation of the hones which come in contact with a large area of the workpiece thereby averaging out both the imperfections of the hones and the bore. This averaging effect occurs in all honing processes and contributes to the accuracy and smooth finish of honed surfaces, especially bores.
Conventional hones and honing apparatus experience a common difficulty and that is controlling or limiting the dimensional increase in bore diameter during honing. That is, most honing machines utilized in machine shops rotate and axially oscillate the hones while the adjustable radial force applied to the hones is controlled by a foot pedal. Thus, although metal removal by honing is relatively slow compared to grinding, most machines depend upon the skill of the operator to efficiently and accurately control or limit the dimensional increase of a workpiece by honing. Obviously, overhoning a workpiece with the result that the completed bore, though smooth, is oversized is not only undesirable but may result in scrapping the workpiece. As explained above, however, although conventional hones are capable of providing extremely smooth inner cylindrical surfaces, dimensional control can be difficult due to the uncontrolled spring bias of the honing tool stones, i.e., the hones will continue to enlarge an opening as long as the tool is used.
An additional problem of honing is maintaining true and accurate on-center honing, especially if the axial length of the bore is relatively short. While this is less a problem in large, dedicated honing machines, maintaining true, on center honing with portable or hand held equipment can be difficult in the best of circumstances.
From the foregoing, it is apparent that improvements in both honing equipment and processes are both desirable and possible.
The present invention provides a novel honing tool or device having a generally cylindrical body including a plurality of axially and radially extending webs to which are attached a like plurality of curved honing blades. A portion of the external surface of each blade remote from the attachment points includes an abrasive coating. The radius of curvature of the curved portion of the blades including the abrasive coating is nominally the same as the radius of the desired finish diameter of the bore. A resilient damper is disposed behind each of the curved blades in an axial passageway in the body of the device. An additional plurality of vanes may be disposed behind the blades to limit their inward translation. Thus, the blades have a limited range of radial translation. The invention also comprehends a double or tandem honing device wherein a pair of the just described honing tools are arranged in axially spaced apart relationship on a common shaft.
While the honing tool or device of the present invention is usable with many components and products, it is especially useful for finishing (honing) bearing openings in steering knuckles undergoing repair. The steering knuckle repair process utilizing the honing tools of the present invention typically first involves one or more passes, i.e., a rough cut and a final cut, with a boring bar to achieve an oversized, reasonably smooth surface in the two bearing openings. A bronze sleeve or liner is then installed in each oversized opening. The blades of one or of a tandem honing tool are slightly radially compressed by an operator and inserted into the sleeve or the pair of axially spaced apart sleeves. The honing tool is then rotated and axially oscillated.
As the honing and bore enlargement progress, the torque required to rotate the honing tool(s) and the reaction torque of the honing tool(s) lessens relatively quickly because of the limited radial travel of the honing blades. When the proper bore diameter has been achieved, the honing tool will rotate relatively freely within the bore. This is an indication to the operator that the honing process is complete. Thus it will be appreciated that a honing process utilizing the honing tools of the present invention is essentially self-limiting or self-controlling. Additionally, with a pair of axially spaced apart bores and two correspondingly spaced apart honing tools, maintenance of accurate, on axis honing is assured.
Thus it is an aspect of the present invention to provide an improved honing tool.
It is a further aspect of the present invention to provide a honing tool having a plurality of curved, stiffly resilient honing blades.
It is a still further aspect of the present invention to provide a honing tool having a plurality of curved resilient honing blades including outer surfaces coated with an abrasive.
It is a still further aspect of the present invention to provide a honing tool having a plurality of curved resilient honing blades including damper material disposed behind each of the blades in a passageway in the tool.
It is a still further aspect of the present invention to provide a honing device having a pair of axially spaced apart honing tools each having a plurality of curved resilient honing blades.
It is a still further aspect of the present invention to provide a honing tool having a plurality of curved resilient honing blades especially suited for honing bearings in vehicle front axles.
It is a still further aspect of the present invention to provide a honing device having a pair of axially spaced apart honing tools each having a plurality of curved resilient honing blades especially suited for honing bearings in vehicle front axles.
Further aspects, advantages and areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.
With reference to
The cylindrical body 12 defines a first plurality of, preferably three, axially extending segments or webs 20. The cylindrical body 12 may, alternatively, define or include two, four or more segments or webs 20. Typically, though not necessarily, cylindrical bodies 12 having relatively smaller diameters may include two segments or webs 20 whereas relatively larger diameter cylindrical bodies 20 may include four or more segments or webs 20. The segments or webs 20 each include an outer curved, radiused surface 22 having a plurality, typically two, three or four radially oriented threaded blind openings 24. The threaded blind openings 24 preferably include a countersunk, i.e., frusto-conical, surface 26. Circumferentially adjacent each of the segments or webs 20 is one of a like plurality of axially extending support ribs or vanes 34. The support ribs or vanes 34 include an axially and circumferentially extending, outer oblique surface 36 which is slightly recessed, i.e., disposed radially inward, from the radiused surfaces 22 of the segments or webs 20. As will be more fully explained subsequently, the support ribs or vanes 34 act as stops or bumpers to limit radially inward translation of the honing blades 40, described below. Limiting the radially inward translation of the honing blades 40 prevents portions of the honing blades 40 from deflecting and exceeding their elastic limits and thus being moved out of a proper, operable honing position as described in greater detail below.
With reference now to
The honing blades 40 each define a structure having a plurality of zones and surfaces of different thicknesses and shapes along their circumference. A first narrow circumferential zone and outer surface 50 has a thinnest region adjacent the edge of the blade 40 and increasing thickness away from the edge of the blade 40. The inner surface of the first circumferential zone and surface 50 and of all the other zones and surfaces is a continuous, smooth, radiused surface “R.” There is a second thicker circumferential zone and outer flat surface 52. The second circumferential zone and outer flat surface 52 includes the chamfered openings 42 and serves to mount the honing blade 40 to the segments or webs 20 of the cylindrical body 12. There is a third thinner circumferential zone and outer flat surface 54. The third circumferential zone and outer flat surface 54 partially controls or provides the resilience (spring constant) of the honing blade 40 and thus the honing force or pressure on the workpiece. A fourth thinner circumferential zone and outer flat surface 56 is similar to the third circumferential zone 54. The fourth thinner circumferential zone and outer flat surface 56 also controls and provides additional resilience (spring constant) to the honing blade 40.
A fifth thicker circumferential zone and outer surface 58 includes both a radiused outer surface 58A and the radiused inner surface “R.” The radiused outer surface 58A of the fifth zone 58 of the blade 40 is coated with an abrasive 60. The abrasive 60 is preferably cubic boron nitride (CBN) which may be applied by electroplating or another material deposition process and which may successfully be used with steel or bronze. Alternatively, a diamond abrasive 60 may be applied to the outer surface 58A of the fifth circumferential zone 58 which may be successfully used with bronze.
Fine or coarse abrasive 60 may be applied to the outer surface 58A of the fifth circumferential zone 58 of the blade 40. A fine abrasive 60 for the honing tool 10 is preferably in the range of from about 150 grit to 210 grit with an operable range of from about 120 grit to 240 grit. A fine abrasive 60 is preferably applied to the outer surface 58A of the fifth zone 58 to a thickness of about 0.007 inches (0.178 mm.). A coarse abrasive 60 for the honing tool 10 is preferably in the range of from about 80 grit to 100 grit with an operable range of from about 60 grit to 120 grit. A coarse abrasive 60 is preferably applied to the outer surface 58A of the fifth circumferential zone 58 to a thickness of about 0.012 inches (0.305 mm.).
Preferably residing behind each of the blades 40 and more specifically behind the fourth zone 56 and the fifth zone 58, in axial passageways 64 are a plurality of resilient dampers 66. The dampers 66 are, in their relaxed state, preferably cylindrical and are fabricated of polyurethane having a Shore A durometer hardness of 40. It should be understood that other resilient materials such as rubber and other elastomers may be utilized rather than polyurethane and that the Shore A hardness of the dampers 66 may vary in the range of from 38 to 42 and wider depending upon such variables as the size of the tool 10, the stiffness of the blades 40 and the nominal speed of rotation of the tool 10. The dampers 66 damp vibrations and chatter of the blades 40 and thus improve the smoothness of the honed surface produced by the honing tool 10.
Referring now to
Referring now to
Referring now to
Referring now to
Then, as illustrated in
At this point of the repair process, the configuration of the honing tools 10A and 10B (as well as of the devices 10 and 70) becomes important. As noted above, conventional prior art honing tools include spring biased hones which have, with regard to the honing process, essentially unlimited radial travel and thus abrade and hone metal, increasing, essentially without limit, the inside diameter of a bore. Here, however, the blades 40 of the honing tools 10, 10A, 10B and 70 have a relatively high spring constant and limited radial travel: they are compressed slightly when inserted in to the sleeves 104 such that they apply between one and ten pounds of pressure per square inch and with relatively little radial translation, due to enlargement of the sleeve 104, return to their relaxed positions or nearly so and exert minimal pressure.
Thus, with relatively little metal removal and little diametral increase, the blades 40 relax and provide less force which allows the honing tool 10 to rotate more easily within the sleeve 104. Such easy rotation of the honing tool 10 is an indication that the sleeve 104 has reached the desired inside diameter, i.e., just slightly larger than the diameter of the king pin (not illustrated). Thus, because of the configuration of the honing tool 10, particularly the blades 40, the honing operation is substantially self-limiting or self-controlling.
The steering knuckle 100 can now be re-assembled to the axle by inserting the kingpin through the sleeves 104 in the bearing openings 102 and the opening in the end of the axle and re-attachment of the steering components to the steering knuckle 100 (all not illustrated).
It will be appreciated that although utilization of the present invention has been described in conjunction with use of the double hone device 80 on the steering knuckle 100, the double hone device 80 has application to any honing process or procedure requiring honing of two axially spaced apart cylindrical surfaces and the single hone tools 10 and 70 may be used in any honing application of a single cylindrical surface. Alternatively, the single hone tools 10 and 70 may be used with axially spaced apart cylindrical surfaces although, typically the result, i.e., the axial alignment and concentricity of the two or more cylindrical surfaces will not be that achievable with the double hone device 80. Also, in this regard, it should be understood that more than two, i.e., three, four or more, honing tools 10A and 10B, etc. may be mounted on or integrally formed with a common shaft such as the shaft 82 to simultaneously hone multiple axially spaced apart cylindrical openings.
The foregoing description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
Number | Name | Date | Kind |
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1698590 | Harter | Jan 1929 | A |
1774711 | Heon | Sep 1930 | A |
1853365 | Lindroth | Apr 1932 | A |
2465225 | Haren | Mar 1949 | A |
2476334 | Titcomb | Jul 1949 | A |
2548166 | Larson | Apr 1951 | A |
2580327 | Sunnen | Dec 1951 | A |
2612010 | Phillips | Sep 1952 | A |
3276170 | Crowe | Oct 1966 | A |
3462887 | Hackman, Jr. | Aug 1969 | A |
8690644 | Uchiumi | Apr 2014 | B2 |
20120028550 | Uchiumi | Feb 2012 | A1 |
Number | Date | Country |
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WO 2010114076 | Oct 2010 | WO |
Number | Date | Country | |
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20140141703 A1 | May 2014 | US |