EP0342800A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Making a fractured powder metal connecting rod
Assignee: Ford-Werke GmbH
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Filing: 1989-04-24
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Granted: —
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Expires: 2009-04-24
Abstract
Abstract A method of making a connecting rod (10) for attachment to a bearing journal by separation of parts of the connecting rod, comprising forging a powder metal sintered preform to provide a one-piece connecting rod (10) having an annular wall (13) defining a crank opening (12) with a centre axis and with stress risers (22,23) for establishing a cracking plane (24) that extends across said crank opening; providing access for a compression coupling across the cracking plane, while at ambient conditions, applying tension substantially uniformly across the cracking plane (24) to propagate fracture from the stress risers (22,23) along said cracking plane (24) and thereby separate the connecting rod into a cap (52) and body (53) with cracked surfaces, and remating the cap (52) and body (53) by applying a compression coupling through the access (21) to draw said cap (52) and body (54) together under guidance and with metal yielding pressure to effect substantially an exact rematch of said cracked surfaces.
Inventors
- 👤 Peter Y. Hoag
- 👤 David A. Yeager
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 09:17
CPC Classifications
B; B22; B22F; B22F5/00; B22F5/003; B23; B23D; B23D31/00; B23D31/002; B23D31/003; F; F16; F16C; F16C9/00; F16C9/04; F16C9/045; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49288; Y10T29/49291; Y10T29/49789; Y10T29/4979
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
181 words
A method of making a connecting rod for attachment to a bearing journal by separation of the connecting rod, the method comprising the steps of: (a) forging a powder metal sintered preform to provide a one-piece connecting rod (10) having an annular wall (13), defining a crank opening (12) with a centre axis, said rod (10) being provided with stress risers (22,23) in the annular wall (23) for establishing a cracking plane that extends across said crank opening 12; (b) providing access (21) for a compression coupling across said cracking plane; (c) while at ambient conditions, applying tension substantially uniformly across said cracking plane (14) to propagate fracture from said stress risers (22,23) along said cracking plane (24) and thereby separate said connecting rod (10) into a cap (52) and body (53) with cracked surfaces (56,57), and (d) remating said cap (52) and body (53) by applying a compression coupling through said access (21) to draw said cap (52) and body (53) together under guidance and under metal yielding pressure to effect substantially an exact rematch of said cracked surfaces (56,57).
Claim 2
Independent Claim
181 words
A method of making a connecting rod for attachment to a bearing journal by separation of the connecting rod, the method comprising the steps of: (a) forging a powder metal sintered preform to provide a one-piece connecting rod (10) having an annular wall (13), defining a crank opening (12) with a centre axis, said rod (10) being provided with stress risers (22,23) in the annular wall (23) for establishing a cracking plane that extends across said crank opening 12; (b) providing access (21) for a compression coupling across said cracking plane; (c) while at ambient conditions, applying tension substantially uniformly across said cracking plane (14) to propagate fracture from said stress risers (22,23) along said cracking plane (24) and thereby separate said connecting rod (10) into a cap (52) and body (53) with cracked surfaces (56,57), and (d) remating said cap (52) and body (53) by applying a compression coupling through said access (21) to draw said cap (52) and body (53) together under guidance and under metal yielding pressure to effect substantially an exact rematch of said cracked surfaces (56,57).
Claim 3
Dependent Claim
38 words
A method as claimed in claim 1, in which said stress risers are crack-initiating crevices provided by preformed indentations in said annular wall at opposite sides of said crank opening and extending substantially parallel to said centre axis.
Claim 4
Dependent Claim
53 words
A method as claimed in claim 2, in which said access in step (b) is comprised of threaded fastener openings and said compression coupling is comprised of threaded fasteners received in said openings effective to draw said cap and body together with a force substantially up to the yield limit of said fasteners.
Claim 5
Dependent Claim
62 words
A method as claimed in Claim 3, wherein the threaded fasteners are inserted into said fastener openings and turned sufficient to draw said cap and body together guided by a mock journal to effect substantially an exact rematch of said cracked surfaces, the mock journal being identical to the bearing journal within a diametrical tolerance of plus or minus .0015cm (.0006 inch).
Claim 6
Dependent Claim
66 words
A method as claimed claim 3, in which said fasteners have an unthreaded shank adapted to extend throughout the fastener openings in said cap with a diametrical clearance therebetween, said fasteners being inserted with a band having a smooth surface slidable on said shaft and a curvilinear outer surface with a radial height effective to provide an interference fit with the fastener openings in said cap.
Claim 7
Dependent Claim
82 words
A method as claimed in Claim 1, in which said step (d) comprises assembling said fractured rod portions together at substantially the exact rematch of said cracked surfaces by guided application of compression forces, machining the annular wall defining the crank openings of said connecting rod to final finished dimensions in said remated condition, and providing bearing locking notches at each diametrical side of said annular wall extending across said cracking plane, each notch having a curvilinear radial extremity throughout its length.
Claim 8
Dependent Claim
30 words
A method as in claim 6, in which a pair of said notches are employed, each being parallel to the other and disposed at one side of the crank opening.
Claim 9
Dependent Claim
17 words
A method as in claim 6, in which said notches have a cross-section which is generally rectangular.
Claim 10
Independent Claim
48 words
A method as in any one of the preceding claims, in which said forged powder metal connecting rod resulting from step (a) has a sharpy V-notch value of 6.6 - 10m/kg (10-15 ft/lbs) at 21 o C (70 o F) and a hardness of 30-40 R C .
Claim 11
Dependent Claim
44 words
A method as in claim 9, in which said forged powder metal connecting rod resulting from step (a) additionally has tensile test properties of an ultimate tensile strength of 130-140 ksi, an elongation of 10-15%, and a reduction of area at yield of 30-40%.
Claim 12
Dependent Claim
38 words
A method as claimed in claim 1, in which in step (a) the resulting powder metal connecting rod is a ferrous based metal and has a ratio of mass to cracked surface area in the range of 400-800.
Claim 13
Dependent Claim
37 words
A method as claimed in claim 1, in which in step (a) the forged powder metal connecting rod is aluminium alloy based and has a ratio of mass to cracked surface area in the range of 200-400.
Claim 14
Dependent Claim
39 words
A method as claimed in claim 1, in which said connecting rod is rough-machined prior to step (c), said rod having flat bearing faces adjacent both ends of said annular wall, said flat faces and annular wall being rough-machined.
Claim 15
Dependent Claim
38 words
A method as claimed in claim 1, which additionally comprises a step (e) of finish machining said annular wall by the removal of material to a radial depth effective to remove a major portion of said stress risers.
Claim 16
Dependent Claim
30 words
A method as claimed in claim 2, in which said crack-initiating crevices are machined to provide a V-shaped notch having an included angle in the range of 70-100 o .
Claim 17
Dependent Claim
23 words
A method as claimed in claim 1, in which said stress risers are provided subsequent to the forging of said rod by machining.
Claim 18
Dependent Claim
61 words
A method as claimed in claim 1, in which in said application of tension is carried out by pulling a wedge between a pair of mandrel blocks, each block being in contact with one, but different, side of said connecting rod and different sides of said cracking plane, said wedge having a camming angle in the range of 15-25 o .
Claim 19
Dependent Claim
72 words
A method as claimed in claim 3, in which in step (d) said fasteners have an unthreaded shank adapted to extend throughout the fastener openings in said cap with a diametrical clearance therebetween, said fasteners being inserted with a band having a smooth surface snugly slidable on said shank and having a curvilinear outer surface with a radial height effective to provide an interference fit with the fastener opening in said cap.
Claim 20
Dependent Claim
55 words
A method as claimed in claim 1, in which said application of tension is carried out by continuously pulling apart said rod in a direction perpendicular to said cracking plane to create said cap and body, said pulling being carried out without limiting relative separation movement between said cap and body along said pulling direction.
Claim 21
Dependent Claim
46 words
A method as claimed in claim 19, in which the step of said continuous pulling apart is carried out by holding said cap stationary with reference to the direction of pulling and said body is pulled along said direction with increasing tension across said cracking plane.
Claim 22
Dependent Claim
68 words
A method as claimed in claim 19, in which one of said cap and body is maintained substantially square to the direction of pulling by stops limiting skewing deviation, and the other of said cap and body is maintained square to said pulling direction by securing such other part to a slidable support while controlling the sliding of said support along a track parallel to the pulling direction.
Claim 23
Independent Claim
114 words
An apparatus for fracturing a powder metal bearing support having stress risers to initiate cracking along a predetermined cracking plane and having a sharpy V-notch value of 6.6 - 10m/kg (10-15 ft/lbs) at 21 o C (70 oF ) along with a hardness of 30-40 R c , comprising: (a) a first member for holding one internal side of said bearing stationary, said one internal side being on one side of said cracking plane; and (b) means for continuously pulling a second internal side of said bearing away from said first member in a direction perpendicular to said cracking plane while said second internal side is held substantially square to said direction of pulling.
Claim 24
Independent Claim
114 words
An apparatus for fracturing a powder metal bearing support having stress risers to initiate cracking along a predetermined cracking plane and having a sharpy V-notch value of 6.6 - 10m/kg (10-15 ft/lbs) at 21 o C (70 oF ) along with a hardness of 30-40 R c , comprising: (a) a first member for holding one internal side of said bearing stationary, said one internal side being on one side of said cracking plane; and (b) means for continuously pulling a second internal side of said bearing away from said first member in a direction perpendicular to said cracking plane while said second internal side is held substantially square to said direction of pulling.
Claim 25
Dependent Claim
46 words
An apparatus as claimed in claim 22, in which said means for continuously pulling the second internal side comprises a slide plate having a pin interfitting within the small end of said connecting rod, said slide plate being guided in tracks perpendicular to said cracking plane.
References Cited (Backward Citations)
No citation records indexed.
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