US 3251976 A
Description (OCR text may contain errors)
May 17, 1966 E. F. McBmEN 3,251,976
APPARATUS AND METHOD FOR HEATING REDUCED PORTIONS OF ADJACENT WORKPIECES Filed Dec. 6, 1963 FIG (PRIOR' ART) EDWARD McBRIEN FIG. 4 M75/2343? ATTORNEYS ing the shanks.
United States Patent O 3,251,976 APPARATUS AND METHOD FOR HEATING RE- DUCED PORTIONS F ADJACENT WORKPIECES Edward F. McBrien, Parma, Ohio, assigner to The Ohio Crankshaft Company, Cleveland, Ghia, a corporation of Ohio Filed Dec.` 6, 1963, Ser. No. 328,560
7 Claims. (Cl. 219--l0.69)
The present invention pertains to the art of induction heating and more particularly -to an apparatus and method for heating the reduced portions of adjacent workpieces.
The invention is particularly applicable for heating the reduced ends of adjacent anged workpieces and it will be discussed with particular reference thereto; however, it-will be appreciated that the invention has much broader applications and may be used to heat the reduced Aportions of various shaped workpieces, such as the reduced ends of axle and transmission shafts.
It is often necessary to heat the reduced portions of a workpiece such as the shank of a flanged gear blank for the purpose of annealing or otherwise heat treating the shank. To increase the number of blanks which can be heated in a given time, it has become somewhat common practice to move the gear blanks in side-by-side relationship past an inductor connected to al source of high frequency alternating current. The `gear `blanks `are aligned with the flanges of the blanks abutting each otherAand the Shanks extending in substantially parallel relationship. The inductor may take a variety of congurations; however, generally the inductor is shaped to form a channel having spaced conductors extending along opposite sides of the Shanks as the gearblanks move through the inductor channel.
In this manner, the spaced conductors of the inductor induce a voltage or potential difference into the parallel Shanks, which potential difference causes current to flow within the Shanks. The 12R heating eifect of these currents flowing within the Shanks heat `the Shanks to the desired temperature. The amountof heating is `determined by a variety of factors Such as the power used in energizing the inductor, the magnetic coupling between the inductor and the Shanks, the time the Shanks are within the inlluence of the inductor and the material forming the Shanks, to name only a few.
Since the gear blanks have flanges at one end, the parallel Shanks are spaced from each other as they move through the channel inductor with the amount of spacing being determined by the diilerence in the size of the Shanks and the flanges. When this spacing is large, certain diiculties have been experienced. For instance, the only portion of the parallel Shanks which are heated with any eiciency are the portions immediately adjacent the inductor. .In order to heat all portions of the shank uniformly, the Shanks must be rotated so that the various portions of the `Shanks come into proximity with the inductor. The rotation of the gear blanks as they pass through the channel inductor is not always easy and, in some cases, it requires an external means for rotating the blanks. If the blanks are not rotated, the portions of the Shanks spaced from the inductor must be heated cornpletely by conduction of heat through the material form- This requires a substantial amount of time and, thus, increases the expense of heating the gear blanks.
n The large spaces between the parallel Shanks leave a substantial portion of the volume within the channel inductor completely vacant. This lowers the magnetic coupling of the inductor and decreases the heating efficiency of the inductor. This lowered etliciency is more pronounced When the volume of the spaces between-the ICC adjacent parallel Shanks are quite large, i.e. when the volume of these spaces approaches or exceeds the volume of the Shanks within the channel of the heating inductor.
All of these diiliculties and others are overcome by the present invention which is directed toward an apparatus and method for heating the reduced portions of adjacent workpieces 'which apparatus and method increases the etiiciency of known procedures of this type and which reduces the need for rotating the workpieces to any great extent as they pass through the channel of the heating inductor.
In accordance with the present invention, there is provided an apparatus for simultaneously heating the aligned reduced portions of a plurality of side-by-side workpieces comprising an inductor having a conductor on each side of the reduced aligned portions and a low resistivity, nonmagnetic insert between adjacent reduced portions. In accordance with the invention, the inserts substantially lill the spaces between adjacent reduced portions of the workpieces.
In accordance 'with another aspect of the present invention, there is provided a method for simultaneously heating the reduced portions of a plurality of workpieces comprising: aligning the workpieces in side-by-Side relationship with the reduced portions aligned to produce spaces between adjacent workpieces, substantially lilling the spaces betweenl the reduced portions of adjacent workpieces with inserts of low resistivity, non-magnetic material, passing the workpieces between conductors of an inductor, and energizing the inductor with alternating current.
The primary object of the present invention is the pro vision of an apparatus and method for inductively heating 'simultaneously the reduced portions of a plurality of workpieces by a surrounding inductor 'which apparatus and method result in a higher eciency than was obtainable with known' apparatus and procedures.
Another object of the present invention is the provision of an apparatus and method for inductively heating Simultaneously the reduced portions of a plurality of Workpieces by a Surrounding inductor which apparatus and method limits the amount of rotation of the workpieces which is necessary as they move through the inductor.
Yet another object of the present invention is the provision of an apparatus and method for inductively heating simultaneously the reduced portions of a plurality of workpieces by a surrounding inductor which apparatus and method includes the provision of a loW resistivity insert between adjacent workpieces and in the space caused by the reduced portions. l
A further object of the present invention is the provision of an apparatus and method #for inductively heating simultaneously the reduced portions of a plurality of workpieces by a Surrounding inductor which apparatus and method prevents substantial vacant volume within the volume dened by the inductor.
These and other objects and advantages will become apparent from the following description used to illustrate the preferred embodiment of the invention as read in connection with the accompanying drawings in which:
FIGURE l isa pictorial, partially c ut away view showi-ng somewhat 'schematically' the prior art to which the lpresent invention is directed;
i Referring now to the drawings wherein the showings are for the purpose 'ot illustrating la preferred'embodiment of the invention -only 'and not for the purpose of limiting same, FIGURES l and 2 illustrate the prior fart to which the present invent-ion is'di-re-cted which prior ,art includes an apparatus A for induetively heating simultaneously the reduced l:portions of side-by-side worldpieces B. Although it is appreciated that the workpieces may take a variety of structural shapes, the wonkpieces in @accordance with the illustrated embodiment of the present invention include gear blanks having flanges ld rand Shanks 12 which flanges have a larger transverse dimension than the Shanks.
The .gear blanks B I'are l'received Within a guideway d4 which may be inclined so that the 'gear blanks slide through the lguideway without rotation. Also, the guideway may be placed edgewise aswell as being inclined so that thev gear blanks both rotate and slide along the guideway so th'at the shanks 12 |are uniformly heated in "a `manner to be hereinafter 'described in detail. yThe tguideway indludes spaced .shoulders 16, 1-3 which deiine Ta guide slot 20 having a dimension which will rece-ive `the dange l0' ot blanks B so that the shanks 12 extend youtwardly from the guideway 14 with the shanks being substantially parallel.
The |apparatus :A is yadapted to heat the outermost portion orf shank 12 `so that the end of the shank inlay be annealed, hardened or otherwise heat treated. To accomplish this heating operation, there is provided Ian inductor 30 having spaced parallel oonduictors 32, A34 positioned on opposite 'sides of the v-shtanks l2. The indiretto-r 30 is characterized -a-s having a channel 36 rfor allowing movement of the Shanks `1.2 through the inductor While the shanks are vin inductive relationship with the conductors :312, 34. 'To power the inductor 30, there is provided ya power source 3S which, in laccordance with the preferred embodiment ot the present invention, is la motor generator set developing three lor ten kc. alternating eurrent. It is appreciated lthat the inductor i3() may yhave multi-ple turns or may Ibe wider in an axial 'direction with respect to the Shanks 12 so 'a greater portion of the lShanks lare in inductive relation-ship with the inductor. Thesingle turn indu'ctor 30 is shown only for representative purposes and various other inductors can be provided for simultaneously heating Shanks l2 or similar reduced porti-onsA `on other workpieces. Y
In 'operation of the prior 'ar-t device as shown in FIG- URES .1 fand 2, the gear blanks B are moved through the channel 56 of Vivndufctor 30 by sliding the blanks along guideway 114. Since the flanges 10 have a lgreater transverse dimension than s-hanks l2, there is a considerable vacant space or volume between adjacent Shanks 12. Thus, when :current llows through the conductors 3.2, 34 as shown in FIGURE 2, an induced voltage is developed on opposite sides of Shanks I2 which induced voltage causes a heating current to flow inthe portions of the shank -12 ladjacent the conductors 3K2, 34. Accordingly, only those portions ot the Shanks adjacent the conductors are ydirectly heated and the `remainder of the shank must be heated by conduction. rltlhis is inefficient `and requires a considerably time delay `ttor stabil-ization ot the temperature within the shank `12. Ifthe sh'an-k l2 is to be hardcned, then this localized heating may be even more troublesome because the shank must beV Iraised to a high temperature 4quickly then immediately quenched. To overcome this disadvantage, the blanks B may be rotated so various portions 'of shank l2 are in .close proximity with the .conductors 32, 34. This requires, in Amost instances, a more complicated arrangement for moving the gear blanks B through the channel `3rd. In addition, since there is a-lc-onsiderable amount of vacant space in ehannel 36, the heating eiiiciency of inductor 3d is reduced.
These `disadvantages fare `overcome .by the present invention which is illustrated in FIGURES 3 and-4 wherein inserts 4t) lare positioned between the Shanks 12 as the gear blanks move along gui-deway i4. 'These inserts are formed from a low resistivity, non-magnetic material such as copper. ln :accordance with the illustrated embodiment of the presen-t invention, the blocks du lare rectangular in cross section; however, they are so dimensioned to substantially till rthe spaces between *adjacent `Shanks I12 as is shown in FIGURE 4. It is appreciated that the inserts 4) could have various other configura-tions so that they would till a `greater portion ot the space left vacant because of the difference in diameter of the AShanks 12 and flanges lll.
In some eases, the inert 'may be magnetic; however, this results in la loss tot efficiency and somewhat offsets the `advantage ot the insert. With a magnetic insert, the workpiece ycan still be heated without drastic rotation.` In addition, the insert will lose its magnetic characteristics when .heated above the Curie point Kfor the material forming the inserts.
As shown in FIGURES 3 tand 4, when the gear blanks B slide along the guideway 14 past inductor 3Q, the inserts 4t? `are positioned between the adjacent Shanks 12. rIlhe inductor is energized `and current tiows through lconductors 32, 34 as indicated by the arrows. This now of current in t-he conductors causes fa corresponding current iiow in the insert 40 yas .shown in FIGURE 4. 'Ilhe ourrent ii'ow through the inserts 4t) in turn Icauses .a corresponding ourrent how within the Shanks 12. Consequently, there is an 'even distribution of current flow around the periphery of lshank 12 so .that the `Shanks need not [be rotated to a great extent las they pass longitudinally through the .channel 36 ot' energized induotor St). It `may be necessary to rotate the blanks `B slightly to obtain complete uniformity ot current distribution through the .peripheiy of shank l2; however, if :conductor -is relied upon for even distribution of vheat through sha-nks 12, conduction takes place quite .rapidly because there are only la few areas where the current density is substantiallyr reduced.
With the spaces betweenthe Shanks 12 lle'd by the low resistivity, non-'magnetic inserts di?, the eiciency of vthe inductor .Btl is substantially higher than the etliciency of the inductor when the spaces between the 'shanks are vacant.
It is appreciated that the invention has been described in iconnection with the use of the inserts ttl betweenY Shanks 12 of gear blanks B; however, these inserts could be used between the reduced ends of axle vshafts and transmission shattts las well a-s between the reduced ends oi various other workpieces as they are progres-sed through a channel inductor. The present invention has been described in connection with `centain Istructural embodiments; however, various modifications in these embodiments can be `made without `departing from the intended spirit `and scope of the Jpresent invention as vdefined in the appended Claims.
Vl-ifzwing thus `described 'my invention, I claim:
l. in an apparatus for simultaneously heating aligned reduced Imorti-'ons of a plurality of side-by-'side workpieces includ-ing an inductor having Ea conductor extentling along each side of the reduced aligned portions, 'the improvementoomprising: a low resistivity, non-magnetic insert between adjacent reduced portions, said insert-s substantially filling the space between said adjacent reduced portions.
2g. The improve-ment yas defined in claim ,l wherein said inserts 'are formed from `coppe-r.
3. An apparatus tf'or simultaneously heating the aligned reduced portions of a plural-ity of side-by-side workpieces including `an inductor with .spaced parallel conductors, a mean-s for supporting said workpieces with .Is-'aid reduced portions aligned, means for 'moving said aligned portions between said spaced conductors, a Ilow lresistivity insert between said workpieces Iand .filling the spaces between said aligned reduced portions, said inserts being movable with said workpie'ces, vand la high frequenlcy power source for energizing said inductor yas said work-pieces are passing through said conductors.
4. An apparatus as dened in claim 3 wherein said inserts are non-magnetic.
S. An apparatus a-s dened in claim 4 wherein said inserts fare formed from copper.
y6. An apparatus as deiined in claim 3 wherein said supporting means is a `guideway having means for allowing said workpieces Ito slide through said gfuideW-ay :with said reduced portions extending between said conductors.
7. A 'method ifor simultaneously heating the reduced porti-ons of a plurality of workpieces comprising, aligning the Workpielces in side-lby-side relationship with the reduced portions aligned to produce spaces between the reduced portions of adjacent worhpieces, substantially lling said spaces between the reduced portions of adjacent 6 Workpieces with inserts of lo-W yresistivity material, passing the workpieces between conductors of lan inductor, and energizing said inductor with alternating high frequency current.
References Cited by the Examiner UNITED STATES PATENTS 15 RICHARD M. WOOD, Primary Examiner.
L. H. BENDER, Assistant Examiner.