US2123659A - Making bearings - Google Patents

Description

July 12, 1938.

Original Filed. Nov. 26, 19544 R D. PIKE 2,123,659

MAKING BEARINGS 2 Sheets-Sheet 1 @www A TTORNEYS.

July 12, 193s. R D, PIKE 2,123,659

n MAKING BEARINGS Originl Filed Nov. 26, 1934'. v2 Sheets-Sheet 2 13H-..65 FLW-65 66 NVENTOR. v

v BY

@WM w A TTORN S. l

Patented July 12, 1938 UNITI-:v STATES 2,123,659 MAKING BEARINGS Robert D. Pike, Piedmont, Calif., assignor to Kali! Corporation, Emeryville, Calif.. a corporation of Delaware Application November 26, 1934, Serial No. 754.757

Renewed June"7, 1937 11 Claims. This invention relates to the manufacture of bearings having an iron or steel backing or supporting member with a layer of plastic bronze to form the bearing surface, autogenously, firmly,

'.. uniformly and integrally welded to the backing. Plastic bronze lis a type of bronze the essential constituents of which are either copper or an alloy'high in copper, together `with lead,` the lead content running in practice anywhere from about 15% -or 20% upto 40% or 45% or higher. 'Metals in addition tothe copper and lead are frequently present, generally for the purpose of forming a copper alloy, and these in practice are generally present in amounts running from a fraction of 1% perhaps up to-5%, more prless, the additional metals usually being tin or nickel,

although others may be used.

In my co-pending applications Serial No. 554,785 :(Case AA) filled August 3, 1931, for Compound article and method of making the same, and Serial'No. '709,713 '(Case PP), iled February 5, 1934, for Making bearings, I have described methods of cesti-welding plastic bronze onto an iron or-steel backing. According to such meth- 26 ods the iron or steel back is heated to the neighborhood of 1700 F., and the plastic bronze is heated to the neighborhood of 2000 F. to 2200 F. Superheated flux at a. temperature of about 2550 F.' to 2750 F. is then poured into a space 3.0 defined at least in part by the surface of the steel back to be welded and maintained in contact therewith for a short time, and the molten plastic bronze at the temperature mentioned is then poured into the flux thereby displacing it .36 and thereby contacting with the surface of the steel back to `which it unites with a very strong weld. y

1t is desirable not to have the iron or steel back nor the molten plastic bronze t'o be cast- 40rwelded thereto too hot, and according to said prior applicationsl have maintained the tem-v peratures of these metals below that at which a 'weld would form. The welding or bonding teme perature is thought to be about 1925 F. and with 45, the masses of the two metals 'used according to v' iielm.eia'ture imparted by thesuperheated'ux, 55931; least or a short time, that is, a, vtime long I Bork; avid cations.

(ci. zz-m) enough toeifectbonding. There are disadvan-` tages in maintaining the contact interface be tween the two metals above the bonding temperature for a long time. f

As described in my former applications above 5F mentioned, lthe superheated flux performs the functions of a flux on the iron or steel surface, wets it and raises it to the bonding point, while contact should be of long enough duration to get the desired effects, yet it is desirable, o`f course, 1o not to leave the flux too long in contact with the iron or steel in order to prevent unnecessary -heat interchange. The plastic bronze, likewise according to my former applications above-'mentioned, displaces the flux and, in turn, 'wets the l5 iron or steel surface, yand thus forms the bond therewith.

According to' this present invention I can work with substantially the same temperatures as described in my prior applications above referred to. 20 I thus make use of the superheated flux principle, that is, I'heat the iron or steel andthe plastic bronze to temperatures generally insufficient to cause the best weld and then supply the temperature necessary for the best weld by means e of the super-heated flux, and vI also make use of tie principle of the bronze displacing the flux, both of these in turn wetting the iron or steel: but I vary the method of contacting the `superheated flux and the molten. plastic bronze lwith the surface of the iron or steel to which the plastic bronze is to belwelded. l

A backing o f iron or any suitable composition of steel may b e used, but I generally prefer one made of a soft or mild steel, say with a carbon content less than 0.2%. The invention is likewise applicable to any plastic bronze, but I prefer one having a composition of about '70% of copper and 30% oflead. Any suitable ilux may be used.. ther preferred being made of- Per' cent -Anhydrous borax;A 80

10 as stated in my applications aforesaid, wherein a ilux of 90% of anhydrous borax and 10% of Crynlite -fcryolite is also referred to as 4more or less practical.

An objectl of my invention is to simplify the cast-welding of plastic ronze to iron or. steel when vusing the methods, operating conditions and materials vdescribed in my aforesaid appll- Another object of invention is to provide a method for cast-welding toan iron or steel backing a layer of plastic bronze in such manner that the thickness of said plastic bronze layer may be controlled and varied without changing any of the casting apparatus used. W.

Another object of theinvention is to cast-weld plastic bronze on the inside of a small but long tube of iron or steel.

I Another-object of my invention is to cast-weld as aforesaid a thin liner of the bronze inside of an iron or steel tube without the use of a core.

Another object of the invention is to cast-weld as aforesaid a layer of said bronze which is thinner than the casting space into which it was ing the desired thickness of plastic bronze, and

permitting the balance of the plastic bronze which is in molten. condition to run off.

It also-involves causing a flow through a hollowsteel or iron body, of a column of superheated flux followed by a column of plastic bronze.

I will now refer to alternative exempliiications which are illustrative of my invention.

Referring to the accompanying drawings, which are a part of this specicatiom- Figs. l, 2 and 3 are vertical sections each more or less diagrammatically illustrating different steps in one `exempliiication of my invention; f

Figs. 4 and 5 are similar views illustrating different steps in another exempliiication;

Figs. 6, 7 and 8 are each a similar view of a modification useful with either exempliiication; and

Fig. 9 is asectional view of a completed bearing blank.

Referring to Figs. 1, 2'and 3, a furnace I0 of any suitable design supports a crucible II therewithin for the purpose of heating the flux to the desired temperature indicated above. The crucible II is provided with a cover l2 having an'opening I3 therein. The furnace has'a removable top I4 and an opening I5 therein registering with the opening I3. A suitable number of burner openings, such as I6, are provided in the furnace, which is also provided with a flue I1 for.the escape of products of combustion. The method of heating this crucible, as well as those hereinafter referred to, is, however, not materiaLprovided they are heated and maintained attire desired temperatures.`

Another furnace 20, which may be similar to the furnace I 0, is provided for supporting and heating a Crucible 2I similar'to the crucible I I,

and it likewise has a` cover 22 having an opening 23 therein. The furnace has a cover 24 similar to the cover I4, which likewise has an opening 25 therein registering with th'e opening 23. The furnace 2U is likewise provided with suiiicient burner openings 26, and a flue 21.. C' .A cooling coil 3| is provided which has openings 32 to direct cooling medium to the center of the coil; the cooling medium -being introduced into the coil by a supply pipe 33 having a control terial.v A crucible 35 is provided for receiving surplus flux and metal. According to this modification of my invention,

I weld alayer of plastic bronzethick enough to l form a bearing lining onto the inside of the steel tube 40. With this in view I join this tube, as by welding, to an adaptertube 4I which is preferably somewhat longer than the tube 40, the adapter being closed at the top 42 in which is an outlet the perforations are small enough to prevent the' metal orjiiux dripping out of the tube when held therein by the vacuum. This plate is generally preferable, although it may not in all cases be necessary, depending on the conditions of .op-

eration.

Before dipping the tube 40 in the heated flux in the crucible Il, it may be pre-heated to about 1700 F. in any suitable furnace to speed up the action of the flux, preferably leaving the adapter tube attached thereto as cool as isl economically possible. This tube, which is preferablybut not necessarily heated, is lowered through the openings I5 and I3, the bottom projecting a few inches below the surface of they flux in the crucible I I, as shown on Fig. l. Vacuum is then applied to the outlet 43 whereby superheated flux is drawn up into the tube 40 up to the point where it joins the adapter 4I. The rise of the flux is discernible by the heating up of the tube 40 if it is at a temperature, as it should be. substantially below that of the flux when the ux is applied thereto. Having filled the tube. 40 with superheated flux, it is removed with the vflux therein, as indicated at 41, from the crucible II and furnace I0 and inserted through the openings 25 and 23 into the position shown on Fig. 2 with the bottom thereof below the surface' of the plastic bronze in the crucibl 2|. It is preferable to have the'flux in contact with theY inside o'f the tube 40 preferably for thirty to sixty seconds before displacing the flux with the molten bronze, although the time may be longer or shorter; and vacuum is then agains applied to a sufficient extent, to draw the molten plastic bronze to fill the .tube 40 with plastic bronze 4l,

vthe fflux 41, which was previously in the tube,

crucible 2I and the furnace 20, -and it is then lowered into place centrally within the cooling coil 3|` asshown in Fig. 3, whereupon the coolingA 'medium is turned on and' impinges on the outside of the tube 40. 'I'his causes the formation of a layer of'solid bronze which is 'securely welded to the inside face of the tube 40. Such a layer, under the conditions of operation mentioned, forms very quickly and in ten to .twenty seconds, more or less, will be from twenty to thirty thousandths of an inch thick. The rate of formation of the solid welded-on bronze will, of course, depend upon the nature of the cooling medium used. the pressure at which it is applied, the number of sprays. and other factors; but with any given set-up the operator will speedily learn as a matter of operating technique, the rate at which the layer of solid bronze builds up.

When the solid bronze layer inside the steel tube 40 is thick enough for the particular bearings beingfmanufactured, the vacuum is broken and then the remaining moltenA bronze and,

" thereafter, the molten ilux ow out through the 0, the layer of welded bronze will be thickerv at the bottom of the tube 60 than at the top thereof. This variation ln thickness can be compensated to some extent by lowering the pressure in the cooling coils while lthe metal is draining out so that the remaining cooling effect is just suihcient to prevent the" soft hot bronze from being eroded away from the back, and the draining away of the metalmay be speeded by applying pressure at the outlet d3.

- After Ythe flux andv surplus metal have run out inner side thereof may then be machined into I 35'- of the tube d0, completion of the cooling may be effected in any desired manner, either faster or slower than or at the same rate as it is cooled by the coil 3|, as may be desired. ,It may be dropped into cold water to bring it down to room temperature.

When the tube Si) and the adapter tube dt are sumciently cool, thefadapter is cut away A.

from the tube du and used anew. Thetube d@ with the layer of plastic bronze welded to the bearings.

In the menige illustrated on rigs. a and 5,1

use only one crucible which contains both the molten plastic bronze and the super-heated ux oating thereabove. In such gures, represents a furnace adapted to support andheat the cruciblel. The upper part oi' the furnace is enlarged to form the combustion chamber 52 where preferably the larger portion of the fuel is burned, and for this purpose a suitable number of burner openingsl 53 are provided which lead into the combustion chamber 52; and one or Amore burner openings d leading into the lower part of the furnace may be provided where it appears necessary to heat the lower part of the crucible in addition to the heat derived from the combustion at the upper part of the furnace. A iiue 55 is provided to conduct away products of combustion. Crucible El is provided with a. top te, like nie tops sa and 22 tainsmolten plastic bronze 6d and a layer of superheated uxi iloating thereon. Ihe steel tube 62 to which the plastic bronze is to be welded may be almost closed at its lower end by a perforated plate 63, similarly 46 previously described.

The heating ofthe furnace is so conducted to 'the plate that the temperature of the ilux is kept somewhat hotter than that ofthe metal, the temperatures of the-fluxv and of the metal being preferably those above referred'to.. This is accomplished by` causing the 'major part of the combustion to take place above the level of the bronze.

The tube s2 is'welded to an adapter tube 64, which may shorter than but otherwise of the same structure as the adapter tube 4I, like it being closed at the end 65 and being pro- P1vided with an outlet 66 which is connected to a source of vacuuml (not shown). A holder 6'1 is attached to the upper part of the adapter tube and this holder is carried by an arm 68, .similarfto the arm 45, for the purpose of maintaining the tube to be treated in any desired position or for moving it in any desired manner. A cooling means, such asa hollow coil 69, similar to but not necessarily as long as coil 3i, and having perforations 'l0 similar to the 'perforations 32, is held in relatively fixed position so that the tube to be treated can be drawn therethrough and progressively cooled. Here, again, the cooling material mayv be a liquid such for example as water, atomized in air. I may iirst weld the tube 62 onto the adapter tube tl and then heat the .tube 62 rto about 1700" F. in such a manner as to leave the adapter tube @il relatively cool. The tube 62 may then be dipped into a molten bath of flux, whereupon I may' se. cure the adapter tube 66 to the holder 61 and then connect the outlet Se to the source of vacuum; or I may secure the adapter while cold in the holder t? and connect to the vacuum and thenheat the tube d which is attached to the adapter and iiux it, whereupon it is to be positioned above the center of the coil @9 and openings 59 and 5l. The tube is then quickly lowered into the position shown on Fig. 4 where, as shown, the connection between the tube 62 .and the adapter tube is just below the cooling coil, and the ktube 62 extends to approximately the inside bottom of the crucible. 'mie vacuum is then applied and the metal is thus raised to the point where the tube 62 is connected to the adapter tube. As the metal rises to this level it is preceded by the superheated iiux 'il within the tube and adapter, which prepares all oi the inside surface of the tube 62 to form the desired welded union andso that it is plated in' stantaneou'sly by the molten plastic bronze as it I next start to raise the tube slowly out of its,

initial position, simultaneously turning on the cooling spray in coil 69. The tube is thus raised to the position shown on Fig. 5 and the rate of rise is such that the time required to assume that posi, tion is preferably from thirty to sixty` seconds, although it may be longer or shorter than this. As thetube 62 slowly rises through the superheated ilux 6i, the heat of thev latter causes an intimate and secure plating of the inside face of the tube with the molten bronze which is therewithin; and as the tube continues to rise the zone which has previously passed under the iniiuence of the superheated ux next comes under the inuence of the cooling means, which causes a layer of bronze of appreciable thickness to adhere to the previously referred to plated on bronze so that a. substantial thickness of bronze is securely welded .to the tube. 'I'he thickness of the adherent layer of bronzevwill depend on the speed of rise of the` tube, and on the rate of cooling and, possibly also, on otherl factors. The slower the speed of rise andthe faster the rate of cooling, the thicker will be the solid layer of bronze; and it is practical to I make such layer as thick as one-eighth of an inch or as thinas a few thousandths of an inch, at will,

these ilgures being merely illustrative, The effect of the' cooling coil should be such that the adherent layer of bronze is completely solidified for the desired thickness 'as the adherent layer rises above upper edge of the cooling means. Such solid lager oi' bronze thus continues to rise through the flux pocket 1|', which coats the newly solidified .metal and thus protects it as shown on Fig. 9.

tions in the'plate 63, the entire inside face of the tube 62 will receive a firmly welded-on layer 12 of the bronze as it nally and completely rises above the cooling means. The tube may then be completely cooled by plunging into water and it may then be severed from the adapter. The

v, adapter tube may then be re-used and the dual metal tube may be machined into bearings.

'Ihe bronze may be welded onto theoutside of the tube, if desired, with the use of the device shown in Fig. 6. Here 1I denotes the tube to which the bronze is to be welded; 14, the adapter; and to the tube 13 is welded a thin-walled steel hollow cylinder 15 outside of the tube 13, the two being held concentrically by welded steel strips 16 at the bottom. Holes 11 are provided to permit the vacuum to cause `rise of material between the two tubes as well as within the inner one. 'Ihe outer steel tube may be machined oil to make the finished bearing. It is understood, of course, that coating outside as well as inside `may be accomplished with either exemplication of the invention above described.

The invention has so far been described with respect to straight bearings, but it will be understood that the steel tubes to which the bronze is to be welded may be formed with recesses for flanges, and these may be tapered to preventtrapping of flux therein. As shown on Fig. 7, the tube v18 is formed with outwardly projecting recesses 19 to form flanged bearings when the bearings are cut along the lines 8B. On Fig. 8, the tube 18 is provided with inwardly projecting recesses 8l which likewise will form flanged bearings when cut along the lines I2.

One of the advantages of my invention is that I can choose the thickness of the bronze to be welded onto the tube so that very little bronze turnings will be made in the machining operation.

I have shown certain exempliilcations and modifications of my invention by way of illustration thereof and not as a limitation thereof, sincel changes can be made in my invention without departing from the spirit thereof, the scope of which is defined in the appended claims.

Having described my invention, what I.clairn and desire to secure by Letters Patent is 1. The method of autogenously welding a layer of plastic bronze on iron or steel which comprises dipping a tube of said iron or steel into superheated flux bath, causing said flux to rise in and contact said tube, removing said tube from said bath with the ux therein, dipping it in a bath of molten plastic bronze at a temperature below the welding temperature if said iiux be not superheated, causing said metal to rise in and contact said tube before substantial heat losses occur thereby `to replace the superheated flux and move it upwardly, cooling the outside of said iron or steel lto solidify said bronze progressively away therefrom, and removing remaining liquid when suilicient bronze has solidified.

2. The method of autogenously welding a layer contact said tube, removing said tube from saidv bath with the flux therein, dipping it in a bath of molten plastic bronze at a temperature below the welding temperature if said ilux be not superfrom the time of causing said flux to rise in said tube thereby to replace the superheated flux and move it upwardly, cooling the outside of said iron or steel to solidify said bronze progressively away therefrom, and removing remaining liquid when' sufficient bronze has solidified.

3. .The method of autogenously welding a layer of plastic bronze on iron or steel which comprises dipping a tube of said iron or steel into a bath oi' molten plastic bronze having a layer of superheated flux floating thereon, said molten plastic bronze being at a temperature below the welding temperature if said flux be not superheated, whereby a layer ofV said flux and a column of said bronze enter and contact said tube, causing said 'column and said layer to rise in said tube by creating a vacuum at the top of said tube, raising and simultaneously cooling said tube while mainl taining said vacuum to solidify said bronze progressively away therefrom, and removing remaining liquid when suillcient bronze has solidied.

4. The method of making bearings by castwelding plastic bronze onto an iron or steel tube by heating said tube then treating the surface thereof to be welded with a molten flux and then replacing said flux with said bronze in molten condition, the temperatures of said tube and said bronze being insufficient to cause the marimum firmness of weld, the flux being superheated to a temperature at which heat is imparted to the surface of the tube to be welded to increase the firmness of the weld, said superheated flux and said molten bronze being sucked within 'said tube. said flux being above and preceding said bronze. 5. The method of making bearings by castf welding plastic bronze onto an iron or steel tube by heating said tube then treating the surface thereof to be welded with a molten flux and then replacing said ilux with said bronze in molten condition, the temperatures of said tube and said bronze being insuicient to cause the maximum l firmness of weld, the flux being superheated to a ltemperature at which heat is imparted to the surface of the tube to be welded to increase the firmness of the weld, said superheated flux and' said molten bronze being sucked within said tube, said flux being above. and preceding said bronze, cooling the outside of said iron or steel to solidify said bronze progressively away therefrom, and removing remaining liquid when suiiicient bronae has solidied.

6. The method4 of making bearings by cast--v rmness of weld, the ux being superheated to a( temperature-at which heat is imparted to the surface of the tube to be welded to produce the maximum firmness of weld, saidsuperheated flux and said molten bronze being suckedwithin said tube, said flux being above and preceding said bronze.

welding plastic bronze onto an iron or steel tube by heating said tube then treating the surface thereof to be welded with a molten flux and then replacing said flux with said bronze in' molten condition, the temperatures of said tube and said '1. The method or making bearings by may fro ` bronze being insui'licient to cause the maximum 7i' amm' .ilrmnessotweld,theuxbeinsuperheatedtoa, temperature atwhichheat is imparted to the -suriaceotthetubetobeweldexltopl'oziucethe -maximumiirmnessoi'welmsaidsuperheatediiux andsaidmoltenbronzebeingsuckedwithinaaid tube, said uxbeinzabove andprecedinasaid bronze, cooling the outside of said iron or steel to solidify said bronze procreasively away therefrom,

and removing4 remaining liquid when sumcient bronze has aolidiiled.

8. The method oi making by castweldinzplasticbronzeontoanironorsteeltube by heating said tube, then suckincmolten iiux and molten plastic bronze by application of a vacuum alongY the surface to be welded. said bronze vely replacing said flux, the temperaturesoi saidtubeandsaid bronzeheinzinsuiiicient to cause the maximum ilrmness oi weld, the'iiux being superheated to a temperature at whichheatisimpartedtothesuriaeeofthetube to be welded to produce a better weld, cooling the outside of said iron or steel to solidify said bronze progressively away therefrom while maintaining said vacuum, and breaking said vacuum to permit remaining liquid to iiow out when suiilcient bronze has solidified. Y

9..lfhe' method ot making bearings by east welding plastic bronze onto an iron or steel tube by heating said tube, then sucking moltenux and molten plastic hronzeby appllqltlon ot a vacuumalongthesurfacetobeweldemsaid bronzeprogressively replacing* said iiuxlthe temperaturesoisaidtubeandsaidbronae-beinlinsuiiiciepttocausethemaximumnrmnessofweld. the flux bein: superheated to a temperature at whichheatisimpartedtothesuriaoeotthetuhe tobeweldedtoproduceahetterweld.coolinthe o outside oisaidiron or steeltosolidiiy said-bronael Procreasively away theretromwhile'maintaining saidvacmandbreakingaaidvacuumtopermit remaininzliquidtoilowoutwhensuiiicient bronaehasaolidiiiedwhiledecreasinxthedelreelo .producea coatinzoi'deslred thicknessandre-'w movinltheimaolidiiiedmetal.

, ROBERT D. PIII.

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