U.S. patent application number 11/704040 was filed with the patent office on 2008-08-14 for manufacture and measuring of automotive components.
This patent application is currently assigned to Burgess-Norton, Mfg. Co., Inc.. Invention is credited to Michael J. Dorband, John R. Engquist, Kurt Kujawski, David Molinelli.
Application Number | 20080193320 11/704040 |
Document ID | / |
Family ID | 39678566 |
Filed Date | 2008-08-14 |
United States Patent
Application |
20080193320 |
Kind Code |
A1 |
Engquist; John R. ; et
al. |
August 14, 2008 |
Manufacture and measuring of automotive components
Abstract
Clutch components for automotive use usually include a pair of
clutch members with operative faces. In particular, planar one way
clutches include a pair of clutch members whose operative faces are
enclosed spaced opposition, with each clutch face including a
plurality of recessed defining respective load bearing shoulders. A
plurality of struts are disposed between the coupling face of the
members, and such struts are moveable between the coupling position
and non coupling position. A preferable method of manufacturing
such clutch components includes powder metal operations comprising
die compacting a metal powder into a metal blank, placing the die
compacted metal blank in a machined flat ceramic support, sintering
the metal blank to form a sintered metal blank, and cooling the
sintered metal blank to form a cooled metal blank. The preferred
metallic structure of the cooled metal blank is 50-80% martensite
and 20-50% bainite and fine pearlite. The cooled metal blank is
then measured for flatness, roundness or perpendicular structure in
a measuring devise having supports and probes. Signals from the
probes are analyzed to determine whether the parameters of concern
are within tolerance.
Inventors: |
Engquist; John R.; (Saint
Charles, IL) ; Dorband; Michael J.; (St. Charles,
IL) ; Molinelli; David; (St. Charles, IL) ;
Kujawski; Kurt; (Sandwich, IL) |
Correspondence
Address: |
Edward J. Brosius;AMSTED Industries Inc.
Two Prudential Plaza, 180 N. Stetson, Suite 1800
Chicago
IL
60601
US
|
Assignee: |
Burgess-Norton, Mfg. Co.,
Inc.
|
Family ID: |
39678566 |
Appl. No.: |
11/704040 |
Filed: |
February 9, 2007 |
Current U.S.
Class: |
419/26 |
Current CPC
Class: |
F16D 2250/00 20130101;
F16D 41/00 20130101; B22F 2998/00 20130101; B22F 2999/00 20130101;
B22F 2003/248 20130101; C22C 33/0264 20130101; B22F 2998/00
20130101; B22F 2999/00 20130101; F16D 2300/06 20130101; B22F 3/1028
20130101; B22F 1/0059 20130101; F16D 13/00 20130101; B22F 3/1028
20130101; B22F 2202/03 20130101 |
Class at
Publication: |
419/26 |
International
Class: |
B22F 3/12 20060101
B22F003/12 |
Claims
1. A method of manufacturing an automotive component comprising the
steps of: providing an initial ferrous metal powder, adding a
suitable lubricant to form a lubricated metal powder, die
compacting the lubricated metal powder to form a die compacted
metal blank, placing the die compacted metal blank onto a fixture,
sintering the die compacted metal blank while on the fixture to
form a sintered metal blank, and cooling the sintered metal blank
to form a cooled metal blank.
2. The method of claim 1 wherein the initial ferrous metal powder
is admixed with an additional 0.60-0.90% carbon and 1.0-3.0%
copper, by weight, prior to adding the lubricant.
3. The method of claim 1 wherein the lubricant is one of an
ethylene bis-stearamide wax, metal stearates or other lubricants
suitable for die compaction of a ferrous metal powder.
4. The method of claim 1 wherein the fixture is a flat ceramic
structure designed to support the die compacted metal blank during
sintering.
5. The method of claim 1 wherein the fixture is a precision ground
flat ceramic structure designed to support the die compacted metal
blank during sintering.
6. The method of claim 1 wherein the fixture is a precision flat
ceramic structure designed to support the die compacted metal blank
during sintering and cooling such that the cooled metal blank is
within a desired flatness tolerance.
7. The method of claim 1 wherein the cooled metal blank is measured
for flatness by placing the cooled metal blank in a measuring gauge
which includes support pads and probes, and wherein the cooled
metal blank is held by contacting the support pads and the flatness
of the cooled metal blank is then measured by the probes.
8. The method of claim 7 wherein the probes contacting the cooled
metal blank resulting in a plurality of sizeable that are analyzed
to determine the relative flatness of the cooled metal blank.
9. The method of claim 7 wherein three support pads are utilized to
establish a reference plane.
10. The method of claim 7 wherein the probes are comprised of
pairs, with each pair providing a measurement of an outer diameter
of the cooled metal blank and of an inner diameter of the cooled
metal blank.
11. The method of claim 1 wherein the cooled metal blank is
measured to determine the orientation of perpendicular faces of the
cooled metal blank by placing the cooled metal blank on a measuring
gauge which includes support pads and probes, and wherein the
cooled metal blank is held by contacting the support pads and the
orientation of the perpendicular faces to the flat surface of the
cooled metal blank is then measured by the probes contacting the
cooled metal blank.
12. The method of claim 1I1 wherein the probes contacting the
cooled metal blank result in a plurality of signals that are
analyzed to determine the orientation of the perpendicular
faces.
13. The method of claim 11 wherein these support pads are utilized
to establish a reference plane.
14. The method of claim 1 wherein the cooled metal blank is
measured to determine the relative roundness of the cooled metal
blank by placing the cooled metal blank on a measuring gauge which
includes support pads and probes, and wherein the cooled metal
blank is held by contacting the support pads and the relative
roundness of the cooled metal blank is then measured by the probes
contacting the cooled metal blank.
15. The method of claim 14 wherein the probes contacting the cooled
metal blank results in a plurality of signals that are analyzed to
determine the relative roundness of the cooled metal blank.
16. The method of claim 14 wherein three support pads are utilized
to establish a reference plane.
17. The method of claim 1 wherein the initial ferrous metal powder
comprises, by weight, 0.35-0.55% nickel, 0.50-0.80% molybdenum,
with the balance essentially iron.
18. The method of claim 1 wherein the cooled metal blanks is
comprised predominantly of martensite and bainite metallic micro
structure.
19. The method of claim 1 wherein the cooled metal blank is
measured by placing the cooled metal blank on a measuring gauge
which includes support pads and probes, and wherein the cooled
metal blank is measured by the probes, a plurality of signals are
received from the probes and the signals are analyzed to measure
the cooled metal blank.
20. The method of claim 1 wherein the cooled metal blank is
tempered at a temperature of between 350.degree. F. (175.degree.
C.) and 450.degree. F. (230.degree. C.) to form a tempered metal
blank, the tempered metal blank is then measured by placing the
tempered metal blank on a measuring gauge which includes support
pads and probes, and wherein the tempered metal blank contacts the
support pads and the tempered metal blank is measured by the
probes, a plurality of signals are received from the probes and the
signals are analyzed to measure the tempered metal blank.
21. A method of manufacturing an automotive component comprising
the steps of; providing an initial ferrous metal powder, adding a
suitable lubricant to form a lubricated metal powder, die
compacting the lubricated metal powder to form a die compacted
metal blank, placing the die compacted metal blank on a fixture,
sintering the die compacted metal blank while on the fixture to
form a sintered metal blank, cooling the sintered metal blank to
form a cooled metal blank, and placing the cooled metal blank on a
measuring gauge which includes support pads and probes, wherein the
cooled metal blank is held in a reference plane by contacting the
support pads and the cooled metal blank is then measured by the
probes, the probes sending a plurality of signals that are analyzed
to measure the cooled metal blank.
22. The method of claim 21 wherein the cooled metal blank is
tempered prior to being placed on the measuring gauge.
23. The method of claim 21 wherein the initial ferrous metal powder
comprises, by weight, 0.35-0.55% nickel, 0.50-0.80% molybdenum,
with the balance essentially iron.
24. The method of claim 23 wherein the initial ferrous metal powder
is admixed with an additional 0.60-0.90% carbon and 1.0-3.0%
copper, by weight, prior to adding the lubricant.
25. The method of claim 21 wherein the lubricant is one of an
ethylene bis-stearomide wax, metal stearator or other lubricants
suitable for die compaction of a ferrous metal powder.
26. The method of claim 21 wherein the fixture is a flat ceramic
structure designed to support the die compacted metal blank during
sintering.
27. The method of claim 21 wherein the fixture is a precision
ground flat ceramic structure designed to support the die compacted
metal blank during sintering and cooling such that the cooled metal
blank is within a desired flatness tolerance.
28. The method of claim 21 wherein the probes contact the cooled
metal blank resulting in the plurality of signals that are analyzed
to measure the cooled metal blank.
29. The method of claim 21 wherein the probes send a plurality of
sensing signals that impact and return from the cooled metal blank
and wherein the probes subsequently send a plurality of resulting
signals that are analyzed to measure the cooled metal blank.
30. An automotive component manufactured in a process comprising
the steps of: providing an initial ferrous metal powder, adding a
suitable lubricant to form a lubricated metal powder, die
compacting the lubricated metal powder to form a die compacted
metal blank, placing the die compacted metal blank onto a fixture,
sintering the die compacted metal blank while on the fixture to
form a sintered metal blank, and cooling the sintered metal blank
to form a cooled metal blank.
31. The method of claim 30 wherein the initial ferrous metal powder
is admixed with an additional 0.60-0.90% carbon and 1.0-3.0%
copper, by weight, prior to adding the lubricant.
32. The method of claim 30 wherein the lubricant is one of an
ethylene bis-stearamide wax, metal stearates or other lubricants
suitable for die compaction of a ferrous metal powder.
33. The method of claim 30 wherein the fixture is a flat ceramic
structure designed to support the die compacted metal blank during
sintering.
34. The method of claim 30 wherein the fixture is a precision
ground flat ceramic structure designed to support the die compacted
metal blank during sintering.
35. The method of claim 30 wherein the fixture is a precision flat
ceramic structure designed to support the die compacted metal blank
during sintering and cooling such that the cooled metal blank is
within a desired flatness tolerance.
36. The method of claim 30 wherein the cooled metal blank is
measured for flatness by placing the cooled metal blank on a
measuring gauge which includes support pads and probes, and wherein
the cooled metal blank is held by contacting the support pads and
the flatness of the cooled metal blank is then measured by the
probes.
37. The method of claim 36 wherein the probes contact the cooled
metal blank resulting in a plurality of signals that are analyzed
to determine the relative flatness of the cooled metal blank.
38. The method of claim 36 wherein three support pads are utilized
to establish a reference plane.
39. The method of claim 36 wherein the probes are comprised of
pairs, with each pair providing a measurement of an outer diameter
of the cooled metal blank and of an inner diameter of the cooled
metal blank.
40. The method of claim 30 wherein the cooled metal blank is
measured to determine the orientation of perpendicular faces of the
cooled metal blank to a flat surface of the cooled metal blank by
placing the cooled metal blank on a measuring gauge which includes
support pads and probes, and wherein the cooled metal blanks is
held by contacting the support pads and the orientation of the
perpendicular faces to the flat surface of the cooled metal blank
is then measured by the probes contacting the cooled metal
blank.
41. The method of claim 40 wherein the probes contacting the cooled
metal blank result in a plurality of signals that are analyzed to
determine the orientation of the perpendicular faces.
42. The method of claim 40 wherein three support pads are utilized
to establish a reference plane.
43. The method of claim 30 wherein the cooled metal blank is
measured to determine the relative roundness of the cooled metal
blank by placing the cooled metal blank on a measuring gauge which
includes support pads and probes, and wherein the cooled metal
blank is held by contacting the support pads and the relative
roundness of the cooled metal blank is then measured by the probes
contacting the cooled metal blank.
44. The method of claim 44 wherein probes contacting the cooled
metal blank results in a plurality of signals that are analyzed to
determine the relative roundness of the cooled metal blank.
45. The method of claim 44 wherein the support pads are utilized to
establish a reference plane.
46. The method of claim 30 wherein the initial ferrous metal powder
comprises, by weight, 0.35-0.55% nickel, 0.50-0.80% molybdenum,
with the balance essentially iron.
47. The method of claim 30 wherein the cooled metal blank is
comprised predominantly of martensite and bainsite metallic micro
structure.
48. The method of claim 30 wherein the cooled metal blank is
measured by placing the cooled metal blank as a measuring gauge
which includes support pads and probes, and wherein the cooled
metal blank contacts the support pads and the cooled metal blank is
measured by the probes, a plurality of signals are received from
the probes and the signals are analyzed to measure the cooled metal
blank.
49. The method of claim 30 wherein the cooled metal blank is
tempered at a temperature of between 350.degree. F. (175.degree.
C.) and 450.degree. F. (230.degree. C.) to form a tempered metal
blank, the tempered metal blank is then measured by placing the
tempered metal blank on a measuring gauge which includes support
pads and probes, and wherein the tempered metal blank contacts the
support pads and the tempered metal blank is measured by the
probes, a plurality of signals are received from the probes and the
signals are analyzed to measure the tempered metal blank.
50. An automotive component manufactured in a process comprising
the steps of: providing an initial ferrous metal powder, adding a
suitable lubricant to form a lubricated metal powder, die
compacting the lubricated metal powder to form a die compacted
metal blank, placing the die compacted metal blank on a fixture,
sintering the die compacted metal blank while on the fixture to
form a sintered metal blank, cooling the sintered metal blank to
form a cooled metal blank, and placing the cooled metal blank on a
measuring gauge which includes support pads and probes, wherein the
cooled metal blank is held in a reference plane by contacting the
support pads and the cooled metal blank is then measured by the
probes, the probes sending a plurality of signals that are analyzed
to measure the cooled metal blank.
51. The method of claim 50 wherein the cooled metal blank is
tempered prior to being placed on the measuring gauge.
52. The method of claim 50 wherein the initial ferrous metal powder
comprises, by weight, 0.35-0.55% nickel, 0.50-0.80% molybdenum,
with the balance essentially iron.
53. The method of claim 52 wherein the initial ferrous metal powder
is admixed with an additional 0.60-0.90% carbon and 1.0-3.0%
copper, by weight, prior to adding the lubricant.
54. The method of claim 50 wherein the lubricant is one of an
ethylene bis-stearomide wax, metal stearator or other lubricants
suitable for die compaction of a ferrous metal powder.
55. The method of claim 50 wherein the fixture is a flat ceramic
structure designed to support the die compacted metal blank during
sintering.
56. The method of claim 50 wherein the fixture is a precision
ground flat ceramic structure designed to support the die compacted
metal blank during sintering and cooling such that the cooled metal
blank is within a desired flatness tolerance.
57. The method of claim 50 wherein the probes contact the cooled
metal blank resulting in the plurality of signals that are analyzed
to measure the cooled metal blank.
58. The method of claim 50 wherein the probes send a plurality of
sensing signals that impact and return from the cooled metal blank
and wherein the probes subsequently send a plurality of resulting
signals that are analyzed to measure the cooled metal blank.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to automotive clutch or
transmission components and, more particularly, to so called one
way clutches wherein one or more struts provide a mechanical
coupling between opposed clutch faces and a pair of coaxially
rotateable members, with a method for manufacturing and measuring
such components.
[0002] As explained in U.S. Pat. No. 6,571,926, in such one way
clutches, a driving member engages a driven member.
[0003] The manufacture of such automotive components is set forth
in pending U.S. patent application Ser. No. 11/585,297 filed Oct.
23, 2006, and assigned to the assignee of the present
application.
[0004] A thin flat strut is carried within each of the driving
members' pockets such that a first longitudinal end may readily
engage and bear against the shoulder defined by the corresponding
recess in the driving member. The struts second, opposite
longitudinal end is urged by spring force toward and against the
driven member, thereby contacting a complimentary surface on the
driven member.
[0005] The materials and processing of such clutch components use
high hardenability metals to produce the clutch components. Such
materials can be used as backing plates' in automotive
transmissions. The metallic micro structure of such currently used
materials is nearly 100% martensite which is strong and wear
resistant. However, because the subject clutch component operates
in a contacting environment generating extreme heat, the clutch
component is also susceptible to damage and localized injury from
hot spots. Such hot spots are produced by interaction with mating
friction plates made from a variety of friction materials.
Temperatures in these hot spot zones can approach 1500.degree. F.
(815.degree. C.) or more. Because the currently used materials are
highly hardenable and the hot spot temperatures may exceed the
critical temperature or austentizing temperature for steel, the
metal in the area of the hot spots can be readily transformed into
untempered martensite. Such untempered martensite areas on the
backing plate face of the clutch component can be an initiation
site for brittle fractures which can readily propagate causing
ultimate clutch component failure.
[0006] It is also a concern in the manufacture of such automotive
components using powder metallurgy techniques that the warpage and
possible distortion on the automotive components may result in the
component not being completely flat in surface that are desired to
be flat within tolerance. The sintering and heat treating or
tempering processes are particularly of concern when the die
compacted blank is then subsequently sintered in and heat treated,
their can be a resulting warpage or distortion.
[0007] Accordingly, it is an object of the present invention to
provide an improved automotive component that can withstand the
temperatures generated in a clutch or brake in a transmission
environment, and further that is free of warpage or distortion
within desired tolerance.
[0008] It is another object of the present invention to provide a
method of manufacturing an automotive component that can withstand
the temperatures generated in a clutch or brake transmission
component by use of powder metallurgy techniques including, die
compacting, sintering, quenching and subsequent measurement of the
automotive component to assure freedom from warpage and distortion
within accepted tolerance.
SUMMARY OF THE INVENTION
[0009] In a preferred method of manufacturing an automotive
component in accordance with the present invention, a low alloy
constituent, low hardenability material is utilized that
accordingly requires a more aggressive cooling or quenching
operation to produce a strong martensitic wear resistant hard
structure. The preferred method includes the traditional powder
metallurgy operation of die compacting and sintering that is
followed by a quenching operation wherein the sintered material is
quenched in an environment of a cooling rate that results in a
metallic microstructure that is 50-80% martensitic, 20-50% bainitic
with a small portion of fine pearlite, generally less than 10%.
Quenching may include other quench methods than atmospheric.
Because this material does not have high relative hardenability and
transform as readily to martensite at a quench rate between
1.9.degree. F. and 5.5.degree. F. per second, untempered martensite
is not formed by localized hot spots in the operation of the
automotive component. Because there is almost no untempered
martensite in the metallic microstructure, resulting from high
localized temperatures fracture initiation sites are sufficiently
reduced. The service life of the automotive transmission or clutch
brake component such as a backing plate is greatly extended.
Further, the resulting micro structure from reduction in
hardenability reduces the material's propensity to crack
propagation in the finished component.
[0010] The method of manufacturing an automotive component in
accordance with an embodiment of the present invention includes the
initial provision of a metal pre alloy powder comprising, by
weight, 0.35-0.55% nickel, 0.50-0.85% molybdenum, with the balance
essentially iron, admixing an additional metal powder of 0.60-0.90%
carbon and 1.0-3.0% copper metal powder to form an admixed metal
powder. A suitable lubricant is added to the metal powder mixture
to form a lubricated admixed metal powder. The lubricant is one of
an EBS (Ethylene bis-stearamide) wax, metal stearates or other
lubricant suitable for use in die compaction of metal powders.
[0011] The lubricated admixed metal powder is then die compacted,
usually at a pressure of between 40 and 65 tons per square inch in
the forming die. The die compacted metal blank is then placed on a
precision ground flat ceramic support structure and sintered in an
atmosphere of nitrogen and hydrogen mixture or other atmosphere
suitable for sintering and sinter hardening. An equivalent of the
ceramic support structure, such as a silica or firebrick
arrangement could also be used. The sintering operation itself is
usually conducted at a temperature above 2000.degree. F.
(1090.degree. C.), and most usually at a temperature between
2000.degree. F. (1090.degree. C.) and 2350.degree. F. (1290.degree.
C.) for a period of at least 10 minutes. The sintered metal blank
itself is then cooled or quenched usually while remaining on the
ceramic support structure in a quenching or cooling operation that
reduces the temperature of the sintered blank at a rate of
1.9.degree. F./sec. (1.05.degree. C./sec.) and 5.5.degree. F./sec.
(3.05.degree. C./sec.) metal blank from between 1600.degree. F.
(870.degree. C.) to 2000.degree. F. (1090.degree. C.), to a
temperature of between 450.degree. F. (230.degree. C.) and
500.degree. F. (260.degree. C.). The quenched metal blank is then
tempered at a temperature of between 350.degree. F. (175.degree.
C.) and 450.degree. F. (230.degree. C.) for at least one hour to
properly temper the quenched metal blank.
[0012] Either before or after tempering, the quenched metal blank
is placed on a measuring gauge which includes support pads and
probes. These support pads are usually three in number to support
the quenched metal blank in a reference plane. The probes are
multiple in number, with a usual number totaling twelve, and either
contact the quenched metal blank or else utilize a laser or similar
measuring device to determine the relative flatness, or roundness
or perpendicular structure as desired of the quenched metal blank.
Usually such measuring probes are in pairs such that a measuring
reading near an internal diameter and near an external diameter may
be taken. The signals from the probes are analyzed in a processing
unit such as a computer and the relative flatness, roundness,
perpendicular structure and other desired physical attributes of
the quenched metal blank are then compared to determine if the
quenched metal blank is within tolerance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In the drawings,
[0014] FIG. 1 is a perspective view of a clutch assembly in
accordance with an embodiment of the present invention;
[0015] FIG. 2 is a perspective view of a clutch pocket plate in
accordance with an embodiment of the present invention;
[0016] FIG. 3 is a bottom view of a pocket plate of a clutch
component in accordance with an embodiment of the present
invention;
[0017] FIG. 4 is a perspective view of a notch plate of a clutch
component in accordance with an embodiment of the present
invention;
[0018] FIG. 5 is a bottom view of a notch plate of a clutch
component in accordance with an embodiment of the present
invention;
[0019] FIG. 6 is a perspective view of a measuring device in
accordance with an embodiment of the present invention;
[0020] FIG. 7 is a top view of a support arrangement of a measuring
device in accordance with an embodiment of the present invention,
and
[0021] FIG. 8 is a side view of the support arrangement of a
measuring device in accordance with an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERED EMBODIMENT
[0022] Referring to FIGS. 1-5 of the Drawings, an exemplary clutch
assembly 10 in accordance with an embodiment of the present
invention is seen to include a driving member 12 and a driven
member 14, both of which are rotateable about a common normal axis
16. The exemplary clutch assembly 10 further includes a plurality
of struts 18, disposed between the driving member 12 on the driven
member 14. Struts 18 operate to mechanically couple the driving
member 12 to the driven member 14 only when the driving member 12
rotates in a first direction relative to the driven member 14. Such
an arrangement is typically referred to as a one way clutch.
[0023] More specifically, in the exemplary clutch assembly 10, the
driving member 12 has a clutch face 22 that defines a first
reference surface 24 that extends generally normal to the driving
member's rotational axis 16. A plurality of recesses are defined in
clutch face 22 of driving member 12, with each recess including a
load-bearing shoulder that is operative to abuttingly engage a
first end of a given strut 18 when the driving member 12 rotates in
a first direction. While this embodiment of the invention
contemplates any suitable configuration for the recesses of the
driving member 12, in the exemplary clutch assembly 10 each recess
26 of the driving member 12 is adapted to receive a respective one
of the assembly's struts 18. In such arrangement, struts 18 are
nominally carried by the driving member 12 for rotation therewith
about the axis 16.
[0024] Driven member 14 similarly includes a clutch face 34, in
close-spaced opposition to the clutch face 22 of the driving member
12. Clutch face 34 also includes a reference surface 36 that
extends generally normal to the driven member's rotational axis 16.
The driven member's clutch face 34 also includes a plurality of
recesses 38 which exceed the number of recesses in the driving
member 12. Each of the driven member's recesses 38 is adapted to
receive the second end of a given strut 18 when the strut's second
end is urged into recess 38. Such urging is typically by a spring
seated beneath the strut 18 in the driving members recess. Each of
the driven member's recesses 38 includes a load-bearing shoulder 46
that is operative to engage the second end of a given strut 18 when
the driving member 12 rotates in the first direction relative to
the driven member 14. Driver member 14 includes a back face
friction plate. This back face is subjected to intense localized
heating in use.
[0025] The material for the clutch or transmission components of
the present invention is a low alloy, low hardenability material
that is subjected to an aggressive cooling or quenching operation
to produce a strong martensitic, wear resistant metallic structure.
The method of the present invention results in clutch or
transmission components that have the desired properties.
[0026] In general, a method of manufacturing an automotive
component in accordance with one aspect of the present invention
comprises the steps of providing an initial pre alloy metal powder
comprising, by weight, 0.35-0.55% nickel, 0.50-0.85% molybdenum,
with the balance essentially iron. Then an additional 0.60-0.90%
carbon, 1.0-3.0% copper metal powder are admixed to the initial
metal powder to form an admixed metal powder. A suitable lubricant
is added in accordance with powder metal practice to form a
lubricated, admixed metal powder. The lubricated admixed metal
powder is then die compacted, typically at a pressure of between 40
and 65 tons per square inch, to form a die compacted metal blank.
The die compacted metal blank is then sintered to form a sintered
metal blank. The die compacted metal blank is placed on a precision
ground of otherwise flat ceramic fixture 11. The flat face of the
die compacted metal blank is in contact with the flat ceramic
fixture 11. Such sintering typically is conducted at a temperature
above 2000.degree. F. (1090.degree. C.), and more typically at a
temperature between 2000.degree. F. (1090.degree. C.) and
2350.degree. F. (1290.degree. C.). The sintered metal blank, which
is, in one embodiment of the present invention, either the driven
or driving clutch component mentioned above, is then cooled or
quenched to form a cooled metal blank, usually while the sintered
metal blank remains on the flat ceramic fixture 11. The quenching
or cooling operation reduces the temperature of the sintered metal
blank from between 1600.degree. F. (870.degree. C.) to 2000.degree.
F. (1090.degree. C.) to a temperature of 450.degree. F.
(230.degree. C.) and 500.degree. F. (260.degree. C.). It is
desirable that such cooling or quenching be conducted at a rate
between 1.9.degree. F. (1.05.degree. C.) and 5.5.degree. F.
(3.05.degree. C.) per second. The cooled or quenched metal blank is
then tempered at a temperature of between 350.degree. F.
(175.degree. C.) and 450.degree. F. (230.degree. C.) for at least
one hour. The resulting automotive component has a microstructure
that is 50-80% martensitic, 20-50% bainitic, and a small
percentage, usually less than 10%, fine pearlite.
[0027] Because this resulting automotive component material does
not transform as readily to martensite, the component does not
respond to localized hot spots in clutch or transmission automotive
service. Because there is almost no untempered martensite, the
resulting microstructure, which is up to 50% bainitic, eliminates
fracture initiation sites thereby extending the serviceable life of
the clutch or transmission component. Reduction in hardenablity, as
compared to the high hardenability materials previously used in
such clutch brake or transmission components, reduces the materials
propensity to re-hardening which further prohibits crack
development and propagation.
[0028] Either before or after tempering, the cooled metal blank or
tempered metal blank, as appropriate, is placed on a measuring
device 55. The measuring device 55 usually includes three supports
51 such that the quenched metal blank is held in a reference plane.
A plurality of probes 53 then either contact the quenched or
tempered metal blank to determine whether warpage or distortion has
occurred to the point that the desired flatness of the quenched or
tempered metal blank is out of tolerance. Alternately, the probes
53 can be designed to emit a laser or similar signal to obtain the
similar surface configuration information from the quenched or
tempered metal blank.
[0029] The signals from the probes 53 are transmitted to a computer
wherein the shape of the desired surfaces of the quenched or
tempered metal blank are compared to reference to determine whether
the flatness of the quenched or tempered metal blank is within
tolerance.
[0030] Alternately, the probes 53 can be designed to contact edges
or perpendicular structures on the quenched or tempered metal blank
to measure roundness or perpendicularity of the extended sections
of the quenched or tempered metal blank. Similar signals from the
probes 53 are processed and compared to reference information to
determine whether the roundness or perpendicularity of the extended
structure is within tolerance.
[0031] Such a measuring technique provides a rapid determination
whether the quenched or tempered metal blank is within tolerance
for flatness, roundness, perpendicularity, or other design
parameters. The support 51 of the die compacted metal blank on the
machined flat ceramic support greatly contributes to the flatness,
roundness, and perpendicular symmetry of the die compacted metal
blank through the sintering operation. The probes 53 are usually
twelve in number, including pairs that are separated into an inner
set of probes that obtain readings from an inner diameter of the
automotive component, and an outer set of probes that obtain
reading from an outer diameter of the automotive component.
[0032] Certain examples of the method of carrying out the present
invention follow:
EXAMPLE 1
[0033] In a method of manufacturing an automotive clutch component,
an initial pre alloy metal powder of particle sizes between 250 and
1 micron was provided comprising, by weight, 0.45% nickel, 0.65%
molybdenum, with the balance essentially iron.
[0034] An additional 0.7% graphite, and 1.75% copper metal powder
of particle sizes between 150 and 1 micron, by weight, were admixed
to form an admixed metal powder.
[0035] 0.5% EBS was added as a lubricant to form a lubricated
admixed metal powder.
[0036] The lubricated, admixed metal powder was compacted at a
pressure of 45 tons per square inch.
[0037] The die compacted metal blank was then placed on a machined
flat ceramic support and sintered at a temperature 2050.degree. F.
for 15 minutes.
[0038] The sintered metal blank was then quenched while on the
ceramic support metal blank at a rate of 5.4.degree. F.
(3.00.degree. C.) per second from an initial temperature of
(2000.degree. F.) (1090.degree. C.) to a temperature of
(500.degree. F.) (260.degree. C.) per use. The quenched was then
tempered at a temperature of (380.degree. F.) (190.degree. C.) for
60 minutes.
[0039] The resulting material has a metal microstructure that was
50-55% martensitic, 45-50% bainitic and <5% fine pearlite. The
Rockwell hardness of the resulting material was about HRA40.
[0040] The tempered metal blank was then placed on a measuring
device to determine flatness within tolerance. The tempered metal
blank was supported on three support pads. Twelve probes then
contacted various sections of the tempered metal blank. Signals
from such probes were processed in a computer to determine whether
the flatness of the tempered metal blank was within tolerance.
EXAMPLE 2
[0041] In a method of manufacturing an automotive clutch component,
an initial pre alloy metal powder of particle sizes between 250 and
1 microns was provided comprising, by weight, 0.45% nickel, 0.65%
molybdenum, with the balance essentially iron.
[0042] An additional 0.9% graphite, and 1.75% copper metal powder
of particle size between 150 and 1 micron, by weight, were admixed
to form an admixed metal powder.
[0043] 0.5% EBS was added as a lubricant to form a lubricated
admixed metal powder.
[0044] The lubricated, admixed metal powder was compacted at a
pressure of 45 tons per square inch.
[0045] The die compacted metal blank was then placed on a ceramic
support and sintered at a temperature 2050.degree. F. for 15
minutes.
[0046] The sintered metal blank was then quenched while on the
ceramic support at a rate of 1.9.degree. F. (1.05.degree. C.) per
second from an initial temperature of (2000.degree. F.)
(1090.degree. C.) to a temperature of (500.degree. F.) (260.degree.
C.) per use. The quenched metal blank was then tempered at a
temperature of (380.degree. F.) (1090.degree. C.) for 60
minutes.
[0047] The resulting material has a metal microstructure that was
60-65% martensitic, 35-40% bainitic and <5% fine pearlite. The
Rockwell hardness of the resulting material was about HRA50.
[0048] The tempered metal blank was then placed on a measuring
device to determine flatness within tolerance. The tempered metal
blank was supported on three support pads. Twelve probes then
contacted various sections of the tempered metal blank. Signals
from such probes were processed in a computer to determine whether
the flatness of the tempered metal blank was within tolerance.
EXAMPLE 3
[0049] In a method of manufacturing an automotive clutch component,
an initial pre alloy metal powder of particle size between 250 and
1 micron was provided comprising, by weight, 0.45% nickel, 0.65%
molybdenum, with the balance essentially iron.
[0050] An additional 0.9% carbon, and 1.75% copper metal powder of
particle size between 150 and 1 micron, by weight, were admixed to
form an admixed metal powder.
[0051] 0.5% EBS was added as a lubricant to form a lubricated
admixed metal powder.
[0052] The lubricated, admixed metal powder was compacted at a
pressure of 45 tons per square inch.
[0053] The die compacted metal blank was then placed on a machined
flat ceramic support and sintered at a temperature 2050 for 15
minutes.
[0054] The sintered metal blank was then quenched while on the
ceramic support at a rate of 1.9.degree. F. (1.0.degree. C.) per
second from an initial temperature of (2000.degree. F.)
(1090.degree. C.) to a temperature of (500 .degree. F.)
(260.degree. C.) per use. The quenched metal blank was then
tempered at a temperature of (380.degree. F.) (190.degree. C.) for
60 minutes.
[0055] The resulting material has a metal microstructure that was
80% martensitic, 20% bainitic and <1% fine pearlite. The
Rockwell hardness of the resulting material was about HRA58.
[0056] The tempered metal blank was then placed on a measuring
device to determine flatness within tolerance. The tempered metal
blank was supported on three support pads. Twelve probes then
contacted various sections of the tempered metal blank. Signals
from such probes were processed in a computer to determine whether
the flatness of the tempered metal blank was within tolerance.
* * * * *