AU463513B2 - Composite heavy-duty mechanism element and method of making thesame - Google Patents

Description

37044/71

The present invention relates to a composite heavy-duty mechanism element and method of making the same.

Heavy-duty mechanism elements which during operation

are subjected to heavy-loads or stresses have hitherto been formed

from high-cost nickel-content alloys which in themselves are very

expensive and which consequently cause such mechanism elements

made therefrom to be likewise very expensive. In actual fact,

however, only a portion of such mechanism elements is ordinarily

subjected to concentrated heavy loads, torques or stresses which require the use of high performance alloys, yet the formation of

the entire mechanism element therefrom has hitherto been required

and has been of excessively high cost of production not only from

the high cost of the alloys themselves but also from the expensive

forging operations required in its production. According to the present invention, there is provided

a composite heavy-duty mechanism element comprising an annular

supporting member of low-performance sintered powdered metal

particles, and an annular working member of high performance Sin-

tered powdered metal alloy particles disposed in coaxial surface-

to-surface engagement therewith in press-fitted relationship at the junction surface therebetween said junction surface being sub-

stantially frusto-conical surface. According to an aspect of the present invention there is

provided a method of making a composite heavy-duty mechanism

element, comprising confining an annular mass of low-performance metal particles in an annular enclosure, with a frusto-conical side

surface confining an annular mass of high-performance powdered

alloy particles in an annular enclosure having a frusto-conical

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side-wall surface configured to impart to said high performance

mass a surface adapted to mate with a surface of said low-

performance mass, compacting each mass separately in its respective

annular enclosure, sintering each such compacted mass, and pressing

said masses into particle-interlocking mating engagement at said

frusto-conical surfaces subsequent to said sintering.

A preferred embodiment of the present invention will

hereinafter be described with reference to the accompanying draw-

ings in which: Figure 1 is a central vertical section through the die

cavity of a briquetting press showing the positions of the various

parts at the commencement of briquetting the outer heavy-duty or

working component of the heavy duty bevel pinion shown in Figure 6;

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Figure 2 is a view similar to Figure 1 but show- ing. the positions of the various parts at the termination of the briquetting operation; Figure 3 is a central vertical section through the die cavity of a briquetting press showing the positions of the parts at the commencement of the briquetting operation of the inner or supporting or hub component of the bevel pinion shown in Figure 6; Figure 4 is a view similar to Figure 3 but showing the positions of the parts at the termination of the briquetting operation; Figure 5 is a central vertical section through the inner and outer components for the bevel pinion shown in Figure 6, at the commencement of the assembling operation for uniting said outer and inner components; Figuare 6 is a central vertical section through the composite heavy-duty bevel pinion formed in the manner shown in Figures 10 to 14 inclusive, with the dotted lines indicating the roots of the teeth thereon; Figure 7 is a central vertical section through. the die cavity of a brdiquetting press, showing the formation of the inner component of the composite heavy-duty inner race of Figure 10, used in the heavy- duty tapered roller bearing unit shown in Figure 16; Figure 8 is a central vertical section through the die cavity of a briquetting press, showing the formation of the outer heavy-duty component of the composite heavy-duty inner race for the tapered roller bearing unit of Figure 16; Figure 9 is a central vertical section through

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the composite heavy-duty inner race of Figure employing the inner and outer components of Figures 7 and 8, prior to the machining of the annular roller path channel therein; Figure 10 is a view similah: to Figure 9 with the inner race before machining shown in dotted lines and after-such machining shown in solid lines; Figure 11 is a central vertical section through a composite sintered powdered metal blank of high- performance alloy powder inside and low-performance metal powder outside prior to deformation into the outer race of a heavy-duty tapered roller bearing unit; Figure 12 is a -entral. vertical section through the die cavity of a press showing in dotted lines the blank of Figure 11 and in solid lines the same blank after deformation into a composite heavy-duty outer race for the tapered roller bearing unit shown in Figure 16; Figure 13 is a central vertical section through a modified composite sintered powdered: metal blank of high-performance alloy powder above and low-performance metal powder below, prior to deformation into the same outer race for the same heavy-duty-tapered roller bearing unit shown in Figure 16; Figure 14 is a central vertical section through the die cavity of a press similar to that shown in Figure 12, but showing in dotted lines the blank of Figure 13 and in solid lines the same blank after deformation into the same composite heavy-duty outer race for the same tapered roller bearing uni4 shown

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in Figure 16;

Figure 15 is a central vertical section through the composite outer race formed as shown in Figures 11 and 12 or as in Figures 13 and 14; and

Figure 16 is a central vertical section through

a tapered roller bearing unit employing the composite heavy-duty inner and outer races formed in the manner

shown in Figures 7 to 15 inclusive. Referring to the drawings in detail, Figures

I to 6 inclusive show the adaptation of the present invention to the production of a composite heavy-duty

bevel pinion, generally designated 20 (Figure 6) con- sisting of an inner component 22 of low-performance sintered powdered metal, such as sintered powdered

iron, and a toothed outer component 24 of high- performance sintered powdered metal alloy united thereto by pressure forging, as shown in Figure The outer or toothed component 24 is formed by com- high- pressing a charge 26 (Figures I and 2) of a performance powdered metal alloy in the generally frusto-conical die cavity 28 of a briquetting die having cylindrical upper and lower bores 32 and 34 respectively joined by a frusto-conical bore 36. Such a high-performance alloy may consist, for example, of the so-called 4600" modified

alloy, the standard composition of which is ordinarily as follows: 0 to 0.25% Mn.

1.75 to 2.00% Ni. the remainder being Fe. 6 Mo. I 0.35 to 0. 0% .463 13

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The standard 4600" alloy of which the above is a modification has the following com- position: 0.45 to 0.65% Nn. 1.65 to 2.00% Ni. 0.20 to 0.30% Mo. the remainder being Fe. 0.20 to 0.35% Si. The silicon component is omitted in the modified alloy because silicon is detrimental to the working life of a die set. It is ordinarily inserted in the above standard alloy in order to increame the fluidity of the molten alloy during the casting of intricate shapes. The die 30 is mounted in a conventional briquetting press 38 having an upper outer tubular punch 40, a loweer tubular punch 42, and an upper inner solid punch 44. The latter has upper and lower cylindrical portions 46 and 48 respectively inter-. connected by a friisto-conica. portion 50 and reciprocable in upper and lower inner bores 52 and 54 within the tubular punches 40 and 42. The smaller diameter cylindrical portion 48 serves as a nose portion when the inner upper punch 44 is raised together with the outer punch 40 so as to permit filling of the die cavity 28 and at the same time prevent the powdered metal alloy in the charge 28 from dropping into the otherwise open bore 54 within the lower tubular punch 42. Prior to filling the die cavity 26 (Figure 1). the outer upper tubular punch 40 is retracted 'upward

37044/71

so as to uncover the top of the die cavity 26. The

latter is then filled with the charge 28 of high-

performance powdered metal alloy. The outer and

inner upper punches 40 and 44 are then moved downward

in their respective bores 32 and 52, 54 from the

position of Figure I to that of Figure 2 while the

lower tubular punch 42 is moved upward in its respective bore 34 so as to compress the powdered metal alloy

charge 28 between the respective opposing annular end surfaces 56 and 58 (Figure 2) into a briquette

of the same dimensions and proportions as the die cavity 26 and charge 28 at the end of the stroke of

the punches 40, 42 and 44 as shown in Figure 2. The

briquette 60 is then placed in a conventional sintering

oven and sintered in a protective atmosphere such as

hydrogen at conventional sintering times and temperatures well-known to those skilled in the powder metallurgy

art. The workpiece, upon removal from the sintering

oven after sintering, becomes the outer or toothed heavy-duty component 22 of the bevel pinion 20 shown in Figure 6. The inner component 22 of the bevel pinion

is similarly formed (Figures 5 and 6) by placing a charge 62 of low-performance powdered base metal,

such as powdered iron, in the generally frusto-conical

die cavity 64 in a briquetting die 66 which is generally

similar to the briquetting die 30 of Figures 1 and 2

in that it has cylindrical upper and lower bores 68

and 70 respectively joined by a frusto-conical bore

72. Reciprocably mounted in the upper and lower 8 4635 13

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cylindrical bores 68 and 70 are upper and lower tubular punches 74 and 76. M'ounted within the bores 78 and 80 in the upper and lower uubular punches 74 and 76 is a cylindrical core rod 82, the outer cylindrical surface 84 of which, along with the upper and lower cylindrical bores 68 and 70 and the fru.sto-conjical bore 72 constitute the die cavity 64. In making the inner component 22, the upper punch 74 is retracted upward so as to uncover the die cavity 64. The latter is then filled with the charge 62 of low-performance )Dowdered metal, such as powdered iron, whereupon the uppcr punch 74 is moved downward and the lower punch 86 is moved upward so as to compress the powdered metal ubarge 62 between their respective opposing annular end surfaces 86 and 88 respectively into a briquette 90 (Figure The tubular upper punch 74 and lower punch 76 are then moved upward to eject the briquette or compact 90 from the die cavity 64. The briquette or compact 90 is then sintered in the gane manner as described above for the outer com- ponent 24, thereby becoming the inner component 22. The inner component 22 of base metal is then forced into the interior of the sintered high-perfoirmance alloy outer component 24 in a forging operation (Figure producing the composite blank 92. The latter is then cut or ground with bevel teeth 94, whereupon the blank 92 becomes the finished bevel pinion 20 containing an inner bore 96 which is adapted to receive the shaft (not shown) upon which the bevel pinion 20 is to be mounted. 46341 3

37 044 [71 In Figures 7 to 16 inclusive there is shown

the adaptation of the present invention to the production of a heavy-duty tapered roller bearing unit, generally designated 120 (Figure 16) having a composite sintered powdered metal inner race or cone 122 (Figure 10) and a composite sintered powdered metal outer race or cup 124 (Figure 15). The inner race or cone 122 (Figure 10) has an inner component 126 of sintered low-performance powdered base metal, such as powdered iron, united by pressure forging with a sintered high-performance powdered alloy outer component 128. The outer race or cup 124 (Figure 9) has an outer component 130 of sintered low-performance powdered base metal, such as powdered iron, and an inner component 132 of sintered high-performance powdered alloy. The :Inner component 126 of the com- posit. inner race, 122 has a shaft bore 134 therein for receiving the shaft (not shown) to be journaled in the tapered roller bearing unit 120, whereas the outer component 130 of the outer race 124 has a generally cylindrical outer surface 136 adapted to be mounted in a cylindrical bore or counterbore in the housing or other struacture (not shown) in which the bearing unit 120 Is to be mounted. Tapered bearing

rollers 138 (Figure 10) are mounted in the space between the outer and inner races 124 and 122. The inner component 126 of the inner race 122 is formed by placing a chairge (Figure 1) of low- performance powdered base metal, such as powdered iron, adapted, upon compression, to form a compact

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or briquette 140 in the generally frusto-conical

die cavity 142 of a briquetting die 144 having cylin- drical upper and lower bores 146 and 148 respectively

joined by a frusto-conical bore 150. The die 144 is

mounted in a conventional briquetting press 152

having upper and lower tubular punches 154 and 156 respectively reciprocably mounted in the die bores

146 and 148 and operatively connected to reciprocable upper and lower platens (not shown) in the briquetting press 152. Fixedly mounted in the bores 158 and 160 in the upper and lower tubular punches 154 and 156 is a stationary core rod 162, the cylindrical outer surface 164 of which, with the bores 146, 150 and 148, the lower end 166 of the upper punch 154 and the upper end 168 of the lower punch 156, defines the die cavity 142. The charge of powdered base metal is then compacted into the briquette 140 by moving the upper punch 154 downward and the lower punch 156 upward to their final or end-of-stroke positions shown in Figure 1, compressing the powdered base metal charge into the briquette 140 of the same dimensions and proportions as the die cavity 142 at the end of the strokes of the upper and lower punches 54 and 56. The briquette 140 thus obtained is then placed in a conventional sintering oven and sintered in a protective atmosphere such as hydrogen at conventional sintering times and temperatures well known to those skilled in the powder metallurgy art. The work-piece upon removal from the sintering oven after sintering is the inner component 126 of the inner race or cone 122 11 4635 13

37 A44 171

shown in Figure 3.

The outer component 128 of the inner race

122 is similarly formed (3igure 2) by placing a

charge of high-performance powdered alloy metal suitable for forming the desired compact or briquette

170, such as has been described more fully above,

in the generally frusto-conical die cavity 172

in a briquetting die 174, generally similar to the

briquetting die 152 of Figure 1 and having cylindrical

upper and lower bores 176 and 178 respectively joined

by a frusto-conical bore 180 and an annular shoulder

182 connecting the latter to the cylindrical bore 176.

Reciprocably mounted in the upper and lower cylindrical

bores 176 and 178 are an outer upper tubular punch 184

and a lower tubular punch 186. Reciprocably mounted

within the upper and lower bores 188 and 190 of the

outer upper punch 184 and lower punch 186 respectively is an inner upper punch 192 (Figure 2) having upper

and lower cylindrical portions 194 and 196 inter-

connmected by a frusto-conical portion 198. The smaller

diameter cylindrical portion 196 serves as a nose

portion when the inner upper punch 192 is raised

together with the outer punch 184 so as to permit

filling of the die cavity 172 without permitting the

powder in the charge placed therein to drop into the

otherwise open bore 190 within the lower tubular punch

186. In making the outer component 26, the outer

upper tubular punch 84 is retracted upward so as to

uncover the die cavity 172. The die cavity 172 is

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then filled with the charge of high-perffomsnce

alloy powder, whereupon the outer upper punch 184 is moved downward and the lower tubular punch 186 is moved upward so as to compress the powdered alloy

charge between their respective opposing annular end

surfaces 200 and 202 to form the compact or briquette

170. The tubular outer upper punch 184 is then

retracted upward, together with the inner upper punch

192 and the lower tubular punch 186 is at the same

time moved upward to eject the thus-formed compact

170 from the die cavity 172. This compact 170 is then sintered in the same manner as described above

for that of the inner comiponent 126, thereby becoming

the outer component 128. The sintered inner component

126 of base metal is then forced into the interior of the sintered high-performance alloy outer component

128 in a forging operation. The resulting composite blank, generally designated 204, is then ground externally from the contour shown in dotted lines in Figure 4 to the contour shown in solid lines therein so as to produce the annular roller path groove 206, whereupon the blank 204 becomes the finished inner

race or cone 122. In Figures 11 to 14 inclusive there is shown

the formation of the composite outer race 124 for the

heavy-duty tapered roller bearing unit 120 shown in

Figure 16. The outer component 124 is formed in either

of two ways, the first being shown in Figures 11 and 12

and the second in Figures 13 and 14. In Figures 11 and

12, a composite sintered powdeled metal blank 210

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is made by placing a tubular divider (not shown) in

the annular die cavity of a conventional briquetting

press between its core rod and its outer wall at the

place where the junction 212 between the high-

performance sintered metal alloy inner component

214 and the low performance sintered powdered metal

outer component 216 is to be located. The operator

now fills the inner zone of the die cavity with high-

performance powdered metal alloy of the type described

above, then fills the outer zone with low-performance

powdered metal, such as powdered iron, and then with-

draws the tubular divider. He then operates the briquetting press to compress the two powders so that they form a compact or briquette. The latter is then. placed in a sintering oven and sintered, whereupon it becomes the blank 210 with the high performance sintered powdered metal alloy inner component 214 and the low performance sintered powdered metal outer component 216 firmly and inseparably bonded to one another.. The composite sintered powdered metal blank 210 thus produced is then preferably heated to a warm temperature between 800°. and 1375 0 F. or to a hot- temperature of 1375 0 F. to 23000?. and forged into its final shape 124 in a forging press 220 having an annular die cavity 222. The die cavity 22 forms the counterbore of a bore 224 into which the reduced diameter

nose portion 226 of a forging punch 228 extends. The forging punch 228 includes an upper large diameter portion 230 and a frusto-conical portion 232 extending between the large diameter portion 230 and the small 14 4635.13

37.044171

diameter portion 226. The large diameter portion

230 is moved into and out of the cylindrical

bore portion 234 of the die cavity 222, which has

an annular shoulder 236 extending from the small

diameter bore 224 to the larger diameter bore 234 which in turn opens into a slightly larger diameter count erbore 238.

With the forging punch 228 in its raised or retracted position, the thus-heated composite sintered

powdered metal blank 210 is dropped into the die cavity 222 of the forging press 220. The forging

punch 228 is then brought downward upon the heated blank 210, such as by moving downward the platen

(not shown) to which the forging punch 228 is attached,

thereby deforming the blank 210, shown in dotted lines in Figure 12, into the final shape of approximately triangular cross-section shown in solid lines in

Figures 12 and 16, thereby producing the composite outer race or cup 124. The latter is then ejected. from the die cavity 222. In Figures 13 and 14 is shown an alternate

method of producing the composite sintered powdered metal outer race or cup 124 from an annular blank 240

shown in Figure 13. The annular blank 240 is also

produced in the die cavity of a conventional briquetting

press (not shown), and consists of an annular lower

sintered powdered metal portion 242 of low performance

metal, such as powdered iron, and above it an annular

37. 0 44 Pf upper sintered powdered metal portion 244 of high- performance metal alloy, such as described above firmly and inseparably bonded to one another. The method of producing the blank 240 is generally similar to that described above in connection with the blank 210 of Figures 11 and 12, except that the tubular separator is not used. Instead, the operator places in the annular die cavity a charge of low performance powdered base metal, such as powdered iron, and afterward super- imposed upon it a layer of high-performance powdered metal alloy, whereupon the briquettIng press compresses the thus superimposed powders into a compact or briquette which, after sintering in a conventional sintering press, preferably in a protective atmosphere, such as hydrogen, becomes the composite blank 240. The composite blank 240 is now heated to either of the temperature ranges mentioned above in connection with the blank 210 and then forged into its final shape 124 in the forging press 250. The. latter is similar in construction and operation to the forging press 220, hence similar parts are designated with the same reference numerals, except that an inclined annular shoulder 252 extends from the upper counterbore 238 to the cylindrical portion 234 of the lower counterbore 222. -With the forging punch 228 in Its raised or retracted position, the thus-heated sintered powdered metal blank 240 is dropped into the die cavity 222 of the forging press 220, whereupon the forging punch 228 is moved downward into the die cavity 222, thereby deforming the blank 240 from the dotted line position 16 1 4635,1-3

37 044 /71 shown in Figure 16, thereby producing the composite outer race or cup 124. The latter is then ejected from the die cavity 222.

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Claims (1)

1. 37.044/71 The claims defining the invention are as follows

   I. A composite heavy-duty mechanism element

   comprising an annular supporting member of low-performance

   sintered powdered metal particles, and an annular working

   member of high performance sintered powdered metal alloy

   particles disposed in coaxial surface-to-surface engage-

   ment therewith in press-fitted relationship at the junction

   surface therebetween said junction surface being a substant-

   ially frusto-conical surface.

   2o A composite heavy-duty mechanism element,

   according to claim 1, wherein said members are disposed

   in surface-to-surface forged engagement with one another.

   3. A composite heavy-duty mechanism element,

   according to claim 2, wherein said working member has an

   annular array of gear teeth thereon,

   4. A composite heavy-duty mechanism element

   according to claim 3, wherein said gear teeth are inclined

   at acute angles relatively to the axis of said members.

   A composite heavy-duty mechanism element,

   according to claim 1, wherein said working member is

   disposed externally of said supporting member.

   6. A composite heavy-duty mechanism element, according

   to claim 5, wherein said working member has a substantially

   frusto-conical roller path on the exterior thereof.

   7. A composite heavy-duty mechanism element,

   according to claim 6, wherein said roller path comprises

   an annular external groove with a substantially frusto-

   conical bottom surface therein.

   8. A method of making a composite heavy-duty mechanism

   element, comprising confining an annular mass of low- 18 463513

   37 044 71 performance metal particles in an annular enclosure with

   a frusto-conical side wall surface confining an annular

   mass of high-performance powdered alloy particles in an

   annular enclosure having a frusto-conical side wall surface

   configured to impart to said high performance mass a surface

   adapted to mate with a surface of said low-performance mass,

   compacting each mass separately in its respective annular enclosure, sintering each such compacted mass, and pressing

   said masses into particle-interlocking mating engagement

   at said frusto-conical surfaces subsequent to said sintering.

   9. A method, according to claim 8, wherein the high-

   performance alloy particle mass is disposed externally

   of the low-performance metal particle mass during said

   pressing step. A method, according to claim 8, including forming

   teeth in the high-performance alloy particle mass.

   11. A method, according to claim 8, including forming

   an annular roller path on the.high-performance alloy particle

   mass.

   12. A method, according to claim 10, including

   inclining said teeth relatively to the axis of. said mass

   during.formation of said teeth.

   13. A method, according to claim 11, including

   recessing said roller path into said high-performance

   alloy particle mass during formation of said roller path. 14. A composite heavy-duty mechanism substantially

   as hereinbefore described with reference to the accompanying drawings. A method of making a composite heavy-duty

   mechanism substantially as hereinbefore described with

   -19- 4635.13

   37 044 /71 reference to the accompanying drawings.

   Dated: June 26, 1975.

   PHILLIPS ORMONDE AND FITZPATRICK

   Patent Attorneys for:

   FEDERAL.- MOGUL CORPORATION

   4635.13