U.S. patent application number 10/685766 was filed with the patent office on 2005-04-21 for arrangement for crankshaft straightening.
Invention is credited to Bustamante, Anthony T..
Application Number | 20050081378 10/685766 |
Document ID | / |
Family ID | 34520667 |
Filed Date | 2005-04-21 |
United States Patent
Application |
20050081378 |
Kind Code |
A1 |
Bustamante, Anthony T. |
April 21, 2005 |
Arrangement for crankshaft straightening
Abstract
An arrangement for straightening a bent crankshaft is provided.
In a crankshaft manufacturing process, a hardened crankshaft is
measured and compared to reference tolerance specifications. If the
crankshaft is determined to be out tolerance, data identifying the
out of tolerance location and quantity is generated and the
crankshaft is selectively induction rehardened in predetermined
areas as a function of the measurement data to remedy the out of
tolerance condition. The crankshaft is then remeasured and the
process repeated until the crankshaft is within the reference
tolerance specifications. The results can be logged to facilitate
matching of subsequent detected out of tolerance conditions.
Inventors: |
Bustamante, Anthony T.;
(Sterling Heights, MI) |
Correspondence
Address: |
DAIMLERCHRYSLER INTELLECTUAL CAPITAL CORPORATION
CIMS 483-02-19
800 CHRYSLER DR EAST
AUBURN HILLS
MI
48326-2757
US
|
Family ID: |
34520667 |
Appl. No.: |
10/685766 |
Filed: |
October 15, 2003 |
Current U.S.
Class: |
29/888.08 ;
29/402.19; 29/888.011 |
Current CPC
Class: |
Y10T 29/49286 20150115;
Y10T 29/49748 20150115; Y10T 29/49233 20150115; Y02P 10/253
20151101; C21D 9/30 20130101; B21D 3/16 20130101; C21D 1/00
20130101; Y02P 10/25 20151101; C21D 1/10 20130101; C21D 2221/00
20130101 |
Class at
Publication: |
029/888.08 ;
029/888.011; 029/402.19 |
International
Class: |
B21D 001/00; B21D
003/16 |
Claims
What is claimed is:
1. A process for straightening a bent crankshaft after hardening,
the process comprising: generating data indicative of a condition
of crankshaft straightness; comparing the data to a predetermined
tolerance specification to detect an out of tolerance condition; in
response to a detected out of tolerance condition, generating data
indicative of location and quantity of the out of tolerance
condition; and selectively rehardening the crankshaft as a function
of the data indicative of location and quantity of the out of
tolerance condition to remedy the detected out of tolerance
condition.
2. The process of claim 1, wherein selectively rehardening the
crankshaft further comprises: accessing a plurality of
predetermined sets of rehardening parameters to identify a set of
rehardening parameters correlated to the location and quantity of
the out of tolerance condition; and applying these identified
predetermined parameters in the selective rehardening process.
3. The process of claim 1, further comprising: measuring the
rehardened crankshaft to detect any out of tolerance condition; if
an out of tolerance condition is detected, applying a set of
predetermined rehardening parameters correlated to the newly
detected out of tolerance condition; and logging information
regarding unsuccessful rehardening attempt as historical record for
use in correlating subsequent out of tolerance conditions.
4. The process of claim 1, further comprising: measuring the
rehardened crankshaft to detect any out of tolerance condition; and
if an out of tolerance condition is not detected, log information
regarding successful rehardening attempt as historical record for
use in correlating subsequent out of tolerance conditions.
5. The process of claim 1, wherein selectively rehardening the
crankshaft comprises selectively induction rehardening the
crankshaft.
6. A system for straightening a bent crankshaft after hardening,
the system comprising: a processing station including a hardening
apparatus and a measurement apparatus; and a controller coupled to
the hardening apparatus and the measuring apparatus, wherein the
controller is arranged to receive data from the measurement
apparatus, compare the measurement data to predetermined tolerance
specifications to detect an out of tolerance condition, and control
operation of the hardening apparatus as a function of the data to
selectively reharden the crankshaft to remedy an out of tolerance
condition.
7. The system of claim 6, wherein the controller is further
arranged to: instruct the measurement apparatus to measure the
rehardened crankshaft; detect any out of tolerance condition as a
result of the measurement; if an out of tolerance condition is
detected, apply a set of predetermined rehardening parameters
correlated to the newly detected out of tolerance condition; and
log information regarding unsuccessful rehardening attempt as
historical record for use in correlating subsequent out of
tolerance conditions.
8. The system of claim 6, wherein the controller is further
arranged to: instruct the measurement apparatus to measure the
rehardened crankshaft; detect any out of tolerance condition as a
result of the measurement; and if an out of tolerance condition is
not detected, log information regarding successful rehardening
attempt as historical record for use in correlating subsequent out
of tolerance conditions.
9. The system of claim 6, wherein the controller is arranged to
correlate the received measurement data to a plurality of sets of
predetermined rehardening parameters to identify a set of
rehardening parameters correlated to the location and quantity of
the out of tolerance condition, and apply the identified
predetermined parameters as instructions for the hardening system
to use in the selective rehardening process.
10. The system of claim 6, wherein selectively rehardening the
crankshaft comprises selectively induction rehardening the
crankshaft.
Description
FIELD OF THE INVENTION
[0001] The present invention relates in general to manufacturing of
a crankshaft for an internal combustion engine. More specifically,
the present invention relates to an arrangement for straightening
out of tolerance crankshafts.
BACKGROUND OF THE INVENTION
[0002] A typical automotive crankshaft for an internal combustion
engine includes a plurality transition radii or corner areas
located along various points of the crankshaft periphery such as
among the transitions between counterweights, crankpins and main
journals. These corner or transition radii areas are known as
fillets and, under engine loads, may act as stress risers. If these
stress risers are not properly treated, they can result in cracking
of the crankshaft. Therefore, a hardening process is typically used
for automotive crankshafts to deform these fillets and thereby
increase the strength characteristics of these particular regions.
As is known in the art, two commonly used hardening processes are
fillet rolling and induction hardening. Although these hardening
processes are necessary to increase the fatigue strength and thus
the durability of the crankshaft, these processes can result in
distortion of the crankshaft beyond the dimensional specifications
required for today's automotive engines. More specifically, with
induction hardening, residual stresses are created in the
crankshaft that can result in bending and distorting the
crankshaft. As a result, a certain percentage of crankshafts
intended for the automotive industry are bent during the
manufacturing process and are therefore not usable and
scrapped.
[0003] Thus, there is a need for a process to reduce crankshaft
scrap inherent in today's automotive crankshaft manufacturing
processes.
SUMMARY OF THE INVENTION
[0004] Accordingly, the present invention provides an arrangement
for straightening an out of tolerance crankshaft after hardening.
In accordance with one aspect of the present invention, a process
is provided for straightening a bent crankshaft after hardening
that includes generating data indicative of a condition of
crankshaft straightness. The data is then compared to a
predetermined tolerance specification to detect an out of tolerance
condition. In response to a detected out of tolerance condition,
data is generated indicative of location and quantity of the out of
tolerance condition. The crankshaft is then selectively rehardened
as a function of the data indicative of location and quantity of
the out of tolerance condition to remedy the detected out of
tolerance condition.
[0005] In accordance with another aspect of the present invention,
a system is provided for straightening a bent crankshaft after
hardening. The system includes a processing station with a
hardening system and a measuring system. A controller is arranged
to receive information from the measuring system and provide
instructions as a function of the measurement data to the hardening
system to selectively reharden the crankshaft to remedy an out of
tolerance condition.
[0006] In accordance with yet another aspect of this invention,
residual stresses resulting from the induction hardening process
are used to selectively induction reharden the crankshaft in
strategic areas to offset bending that occurred during the typical
induction hardening process of the fillet region areas.
[0007] Additional benefits and advantages of the present invention
will become apparent to those skilled in the art to which this
invention relates from a reading of the subsequent description of
the preferred embodiment and the appended claims, taken in
conjunction with the accompanying drawings.
BREIF DESCRIPTION OF THE DRAWINGS
[0008] Other aspects, features, and advantages of the present
invention will become more fully apparent from the following
detailed description of the preferred embodiment, the appended
claims, and in the accompanying drawings in which:
[0009] FIG. 1 illustrates a schematic of a system for crankshaft
straightening in accordance with the present invention; and
[0010] FIG. 2 illustrates a flowchart of a methodology for
crankshaft straightening in accordance with the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMIENT
[0011] Referring now to the drawings, FIG. 1 illustrates an
exemplary embodiment of a system for straightening an out of
tolerance crankshaft in accordance with the present invention. The
system represented in FIG. 1 would typically be used in a
manufacturing assembly line. Station 10 includes a fixture 15 for
securing a crankshaft in preparation for hardening and measuring.
Station 10 also includes a typical crankshaft measuring apparatus
20 capable of measuring straightness and detecting bent or warped
crankshafts and a typical induction hardening apparatus 30
including multi-axis electromagnetic induction hardening heads
40.
[0012] The crankshaft is induction hardened in the fillet region
areas using the induction hardening apparatus 30 in accordance with
known principles. The crankshaft is then measured using measuring
apparatus 20. During the measuring process, measurement data 50 is
generated and stored for a comparison to reference tolerance
specifications. If the measurement data falls within an acceptable
tolerance specification range, controller 60 allows for release of
the crankshaft from station 10 to be transported to a next station
in the crankshaft manufacturing line. If the measurement data does
not fall within the acceptable tolerance specification range,
controller 60 directs station 10 to retain the crankshaft for
selective induction rehardening to remedy an out of tolerance
condition.
[0013] In the selective induction rehardening process, the
controller 60 sends rehardening control data 70 to the hardening
system 30. The control data 70 includes predetermined rehardening
parameters for use by hardening system 30 to selectively induction
reharden the crankshaft to remedy the out of tolerance condition.
More specifically, upon receiving measurement data indicative of
location and quantity of the out of tolerance condition, controller
60 will match this measurement data to predetermined rehardening
parameters correlated to the location and quantity of the out of
tolerance condition.
[0014] Controller 60 contains these predetermined rehardening
parameters as well as a conventional algorithm that provides for
controller 60 to continuously collect and store in memory 80
empirical data results from testing, experimentation, and actual
production manufacturing of out of tolerance crankshafts in the
selective induction rehardening process. Thus, memory 80 is
continuously populated with measurement data indicative of an out
of tolerance condition, the resultant rehardening parameters
selected for use in the corresponding selective rehardening
process, and whether the selected rehardening parameters were
successful in remedying the out of tolerance condition.
[0015] Upon selectively rehardening the crankshaft, the measurement
apparatus 20 measures the crankshaft and compares it to the
reference tolerance specifications. If the measurement data falls
within the acceptable tolerance specification range, controller 60
allows for release of the crankshaft from station 10 to be
transported to a next station in the crankshaft manufacturing line.
If the measurement data does not fall within the acceptable
tolerance specification range, controller 60 directs station 10 to
again retain the crankshaft for selective induction rehardening to
remedy the out of tolerance condition.
[0016] Referring now to FIG. 2, a methodology for straightening an
out of tolerance crankshaft is illustrated in accordance with the
present invention. In the exemplary embodiment, step 100 involves
induction hardening the crankshaft in the fillet region. Step 110
involves measuring the crankshaft after the induction hardening
process. Step 120 involves comparing the measurement data of step
110 to reference tolerance specifications. Step 130 is the next
step and involves determining if the measurement data is within the
reference tolerance specifications.
[0017] If the result of step 130 is "YES", the crankshaft was not
distorted during the induction hardening of the fillet region in
step 100 and the method continues to step 150 where the crankshaft
leaves station 10 and proceeds to the next processing station.
[0018] If the result of step 130 is "NO", the crankshaft is
distorted beyond the tolerance specifications and the method
proceeds to step 170 where the controller determines data
indicative of location and quantity of the out of tolerance
condition. In step 180, memory is accessed where predetermined sets
of rehardening parameters are stored. These parameters are
correlated to data indicative of a particular location and quantity
of out of tolerance condition. In step 190, a set of rehardening
parameters correlated to the measurement data indicative of the
particular location and quantity of the out of tolerance condition
is identified. In step 200, the identified set for rehardening
parameters is sent to the hardening system as instructions for
selectively induction rehardening the crankshaft.
[0019] In step 210, the bent crankshaft is then selectively
induction rehardened based on the data and instructions sent to the
hardening system from step 200. The crankshaft is then remeasured
in step 220 and compared to reference tolerance specifications in
step 230. The method then returns to step 130 and repeats the
process until the crankshaft is determined to be within the
reference tolerance specifications.
[0020] The foregoing description constitutes the embodiments
devised by the inventors for practicing the invention. It is
apparent, however, that the invention is susceptible to
modification, variation, and change that will become obvious to
those skilled in the art such as using different methods and
processes for hardening the crankshafts. Inasmuch as the foregoing
description is intended to enable one skilled in the pertinent art
to practice the invention, it should not be construed to be limited
thereby but should be construed to include such aforementioned
obvious variations and be limited only by the proper scope or fair
meaning of the accompanying claims.
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