US5565623A
Expired / Lapsed
US
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Method and means for measuring wear in constant velocity joints
Assignee: BOARD OF TRUSTEES OF UNIBERSITY OF ILLINOIS
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Filing: 1995-06-06
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Granted: 1996-10-15
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Expires: 2015-06-06
Abstract
Abstract A computerized gauge for efficiently measuring surface profiles of tracks of constant velocity joints in order to detect defects in the surfaces when rebuilding CV joints. The race is mounted on a support adapted for movement along a translation axis, and a follower is biased into contact with the race along a deflection axis generally orthogonal to the translation axis. An interface ball on the follower, of a size compatible with the track when used in a CV joint, is caused to traverse the track from one end to another while a sequence of data points are recorded indicating the position of the center of the interface ball as it traverses the track. A regressive curve-fitting technique determines a best-fit curve to the set of data points, and a comparison between the data points and a best-fit curve identifies defects in the tested track.
Inventors
- 👤 Michael L. Philpott
- 👤 Dale R. Pankow
- 👤 Douglas Vandenberg
- 👤 Brian P. Welcher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:11
CPC Classifications
G; G01; G01M; G01M13/00; G01M13/04; B; B23; B23Q; B23Q17/00; B23Q17/20; B23Q35/00; B23Q35/04; B23Q35/24
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
230 words
An electronic gauge for constant velocity joints; the constant velocity joints being of the type having an inner and an outer race, the races having complementary ball tracks of precise profile into which are fit drive balls compatible in size with the tracks to closely couple the inner and outer races to produce a constant velocity universal joint relationship between the inner and outer races; the electronic gauge comprising, in combination: a support carrying a stop for locating one of the inner and outer races of a constant velocity joint with a track to be tested in an operative position; a follower mounted for movement along a deflection axis generally perpendicular to the stop; the follower having means for mounting an interface ball of a size compatible with the track under test, means biasing the follower toward the stop so that the interface ball engages the track under test and serves as an interface for the follower; means for producing relative translation between the support and the follower along a translation axis to cause the ball to traverse the track from substantially one end to the other; position indicator means coupled to the follower for producing signals related to deflection of the follower along the deflection axis during the traverse; and a processor for receiving and processing the signals to produce a measure of the surface profile of the track.
Claim 2
Dependent Claim
230 words
An electronic gauge for constant velocity joints; the constant velocity joints being of the type having an inner and an outer race, the races having complementary ball tracks of precise profile into which are fit drive balls compatible in size with the tracks to closely couple the inner and outer races to produce a constant velocity universal joint relationship between the inner and outer races; the electronic gauge comprising, in combination: a support carrying a stop for locating one of the inner and outer races of a constant velocity joint with a track to be tested in an operative position; a follower mounted for movement along a deflection axis generally perpendicular to the stop; the follower having means for mounting an interface ball of a size compatible with the track under test, means biasing the follower toward the stop so that the interface ball engages the track under test and serves as an interface for the follower; means for producing relative translation between the support and the follower along a translation axis to cause the ball to traverse the track from substantially one end to the other; position indicator means coupled to the follower for producing signals related to deflection of the follower along the deflection axis during the traverse; and a processor for receiving and processing the signals to produce a measure of the surface profile of the track.
Claim 3
Dependent Claim
67 words
The combination as set forth in claim 1 wherein the constant velocity joint has a nominal contact angle between the drive balls and the respective tracks of the races, and wherein the interface ball of a size compatible with the track under test has the diameter thereof selected to provide an increased nominal contact angle between the interface ball and the track under test for wear measurement.
Claim 4
Dependent Claim
37 words
The combination as set forth in claim 2 wherein the interface ball is relieved in the range around zero degrees contact angle to prevent bottoming while measuring the surface profile of the track at small contact angles.
Claim 5
Dependent Claim
58 words
The combination as set forth in claim 1, wherein the constant velocity joint has a nominal contact angle between the drive balls and the respective tracks of the races, and wherein the interface ball is relieved in the range around zero degrees contact angle to prevent bottoming while measuring the surface profile of tracks at small contact angles.
Claim 6
Dependent Claim
56 words
The combination as set forth in claim 1 wherein the constant velocity joint has a nominal contact angle between the drive balls and the respective tracks of the races, and wherein the interface ball has a relieved center to establish a minimum contact angle of about 45° between the interface ball and a track under test.
Claim 7
Dependent Claim
48 words
The combination as set forth in claim 1 wherein the position indicator means comprises a first position indicator for producing signals related to the relative translation along the translation axis, and a second position indicator for producing signals related to deflection of the follower along the deflection axis.
Claim 8
Dependent Claim
16 words
The combination as set forth in claim 6 wherein the position indicators comprise linear optical encoders.
Claim 9
Dependent Claim
45 words
The combination as set forth in claim 6 further including a first precision linear bearing for mounting and constraining the support for translation along the translation axis, and a second precision linear bearing for mounting and constraining the follower for movement along the deflection axis.
Claim 10
Dependent Claim
69 words
The combination as set forth in claim 8 further including a linear actuator for translating the support along the translation axis, the biasing means for the follower including spring means for maintaining the interface ball in contact with the track under test during the translation, so that deflection of the follower is a measure of movement of the center of the interface ball as the ball traverses the track.
Claim 11
Dependent Claim
33 words
The combination as set forth in claim 8 further including means for retracting the follower to an inoperative position to allow the locating of a race in an operative position on the support.
Claim 12
Dependent Claim
80 words
The combination as set forth in claim 6 wherein the signals define a progression of (x, y) positional data points for the center of the interface ball as the ball traverses the track, and the processor includes a regressive curve fitting sequence adapted to fit the sets of data points to a best-fit curve, and means for comparing the coordinates of the data points to the best-fit curve to determine track defects in terms of deviations from said best-fit curve.
Claim 13
Dependent Claim
85 words
The combination as set forth in claim 11 wherein the regressive curve-fitting sequence is a double regression including a first regressive curve fitting sequence which determines a first fitted curve using substantially all data points, a data selection which selects data points by comparing the data points to the first fitted curve, and a second regressive curve fitting sequence which determines a second fitted curve using only the selected data points, the second fitted curve being used as the best-fit curve for determining track defects.
Claim 14
Dependent Claim
48 words
The combination as set forth in claim 11 wherein the best-fit curve is an arc of a circle of unknown radius and center before the regressive curve-fitting sequence is performed, and the regressive curve-fitting technique is a circular regression adapted to define the curve by the data points.
Claim 15
Dependent Claim
34 words
The combination as set forth claim 11 wherein the best-fit curve is a straight line, and the regressive curve-fitting technique is a linear regression adapted to define a straight line surface for the track.
Claim 16
Dependent Claim
39 words
The combination as set forth in claim 11 further including display means for displaying the maximum deviation between the coordinates of the data points and the best fit curve as the measure of the surface profile of the track.
Claim 17
Dependent Claim
87 words
The combination as set forth in claim 1 wherein the position indicator means are a pair of linear optical encoders, a first encoder measuring the relative translation between the support and the follower along the translation axis, a second encoder measuring the deflection of the follower along the deflection axis, the processor receiving signals from the optical encoders and obtaining sufficient positional data points during a traverse along a single track to determine the measure of the surface profile of the track of the race being tested.
Claim 18
Dependent Claim
54 words
The combination as set forth in claim 16 wherein the means for producing relative translation produces two traverses of the interface ball across the track, the processor receiving two sets of signals from the optical encoders, and producing two sets of positional data points to measure the surface profile of the track under test.
Claim 19
Dependent Claim
85 words
The combination as set forth in claim 1 wherein the support comprises a table and the stop comprises an upstanding generally cylindrical post for receiving a central opening in a race to be tested, the upstanding post being of a diameter capable of loosely receiving the race to be tested, and the biasing means for the follower being of a magnitude sufficient to move the race against the upstanding post to bring the track to be tested into an operative relationship with the interface ball.
Claim 20
Dependent Claim
37 words
The combination as set forth in claim 18 wherein the gauge is adapted to test an outer race having tracks on the interior thereof, the support being adapted to receive and fix an outer race in position.
Claim 21
Dependent Claim
47 words
The combination as set forth in claim 18 wherein the table has upper and lower levels separated by a step, and wherein an inner race to be tested is seated on the upper level, and an outer race to be tested is seated on the lower level.
Claim 22
Dependent Claim
34 words
The combination as set forth in claim 20, wherein a magnet is embedded in the upper level of the table between the step and the post for positively attracting an inner race under test.
Claim 23
Dependent Claim
38 words
The combination as set forth in claim 18 wherein the support further includes a linear drive for translating the table between an upper and a lower position to produce the relative translation between the support and the follower.
Claim 24
Dependent Claim
46 words
The combination as set forth in claim 1 wherein the mounting means of the follower comprises means for releasably securing the interface ball to the follower in such a way as to cause the interface ball to engage the track under test in an predetermined orientation.
Claim 25
Dependent Claim
174 words
An electronic gauge for races having tracks of the type engaged in operation by drive balls of compatible size which closely fit in the tracks, the tracks having complex profiles potentially carrying defects in the profile, the gauge comprising, in combination: a support for fixing the race with the track in an operative position which is dimensionally undetermined with respect to any reference in the gauge; a follower carrying an interface ball of compatible size adapted to traverse the track from end to end, causing deflection of the ball as the ball traverses the track; means for measuring the deflection of the interface ball as it traverses the track from end to end to produce a sequence of coordinates defining the path of the interface ball; means for performing a curve-fitting regression on the coordinates to define the parameters of a best-fit curve for the coordinates; and means for comparing the coordinates with the best-fit curve to determine deviations from the best-fit curve as a measure of any defects encountered in the traversed track.
Claim 26
Dependent Claim
174 words
An electronic gauge for races having tracks of the type engaged in operation by drive balls of compatible size which closely fit in the tracks, the tracks having complex profiles potentially carrying defects in the profile, the gauge comprising, in combination: a support for fixing the race with the track in an operative position which is dimensionally undetermined with respect to any reference in the gauge; a follower carrying an interface ball of compatible size adapted to traverse the track from end to end, causing deflection of the ball as the ball traverses the track; means for measuring the deflection of the interface ball as it traverses the track from end to end to produce a sequence of coordinates defining the path of the interface ball; means for performing a curve-fitting regression on the coordinates to define the parameters of a best-fit curve for the coordinates; and means for comparing the coordinates with the best-fit curve to determine deviations from the best-fit curve as a measure of any defects encountered in the traversed track.
Claim 27
Dependent Claim
51 words
The combination as set forth in claim 24 wherein the drive balls engage the tracks at a nominal contact angle in normal operation, and the interface ball of compatible size is sized to provide an increased nominal contact angle between the interface ball and the track under test for wear measurement.
Claim 28
Dependent Claim
30 words
The combination as set forth in claim 25 in which the interface ball has a relieved center portion to establish a minimum contact angle for contacting the track under test.
Claim 29
Independent Claim
187 words
A method of determining the depth of imperfections in the surface of a track on a race intended to carry a drive ball of compatible size, the race being selected from a group of races of different curvature, the method comprising the steps of: positioning the race on a support in such a way that the curve is fixed with respect to the support but is dimensionally undefined with respect to the gauge; examining the surface of the track by measuring deflection of an interface ball of compatible size to the track as the ball is caused to traverse the track; producing as a result of the examination step a succession (x, y) coordinates defining the position of the center of the ball as the ball traverses the track; processing the set of coordinates with a regressive curve-fitting technique to minimize any errors between the coordinates and points on a reference curve whose shape and orientation are determined by the regressive curve-fitting technique; and identifying deviations between the coordinates and the determined curve as measures of the depth of any defects in the surface of the track.
Claim 30
Independent Claim
187 words
A method of determining the depth of imperfections in the surface of a track on a race intended to carry a drive ball of compatible size, the race being selected from a group of races of different curvature, the method comprising the steps of: positioning the race on a support in such a way that the curve is fixed with respect to the support but is dimensionally undefined with respect to the gauge; examining the surface of the track by measuring deflection of an interface ball of compatible size to the track as the ball is caused to traverse the track; producing as a result of the examination step a succession (x, y) coordinates defining the position of the center of the ball as the ball traverses the track; processing the set of coordinates with a regressive curve-fitting technique to minimize any errors between the coordinates and points on a reference curve whose shape and orientation are determined by the regressive curve-fitting technique; and identifying deviations between the coordinates and the determined curve as measures of the depth of any defects in the surface of the track.
Claim 31
Dependent Claim
50 words
The method as set forth in claim 27 wherein the step of examining the surface includes producing relative translation between the race and a follower carrying the interface ball to produce a sequence of coordinates of the center of the ball as it traverses the track during the relative translation.
Claim 32
Dependent Claim
92 words
The method as set forth in claim 27, wherein the regressive curve fitting technique is a double regression comprising the step of performing a first regressive curve fitting using all data points to determine a first fitted curve, comparing the data points to the first fitted curve and selecting certain data points according to predefined criteria to eliminate data points which deviate substantially from the first fitted curve, performing a second regressive curve fitting using the selected data points to generate a second fitted curve which is used as the reference curve.
Claim 33
Dependent Claim
49 words
The method as set forth in claim 27 in which the race has a curvature defined by the arc of a circle of undefined radius and center, the step of processing including performing a circular regressive curve-fitting sequence to define a best-fit circular arc to the set of coordinates.
Claim 34
Dependent Claim
41 words
The method as set forth in claim 30 wherein the step of identifying deviations comprises comparing the best-fit radius of the best-fit curve to an empirical radius determined from the coordinates to identify deviations between the coordinates and the determined curve.
Claim 35
Dependent Claim
48 words
The method as set forth in claim 27 in which the step of producing comprises taking the outputs of a pair of linear transducers to produce a sequence of (x, y) coordinates relating to the deflection of the ball by the track as the ball traverses the track.
Claim 36
Dependent Claim
76 words
The method as set forth in claim 27 wherein the drive ball has a nominal contact angle for engagement with the surface of the track during normal operation, and wherein the step of examining the track traverses the track with an interface ball of a size compatible with the track under test having the diameter thereof selected to provide an increased nominal contact angle between the interface ball and the track under test for wear measurement.
Claim 37
Dependent Claim
41 words
The method as set forth in claim 33 wherein the interface ball is relieved in the range around zero degrees contact angle to prevent bottoming while the ball is caused to traverse the track in the step of examining the track.
Claim 38
Independent Claim
231 words
A method for automatically gauging the surface profile of tracks of constant velocity joints; the constant velocity joints being of the type having an inner and an outer race, the races having complementary ball tracks of precise profile into which are fit drive balls compatible in size with the tracks to closely couple the inner and outer races to produce a constant velocity universal joint relationship between the inner and outer races; the method comprising the steps of: mounting one of the inner and outer races of a constant velocity joint with a track to be tested in an operative position; engaging a follower with the track by means of an interface ball of a size compatible with the track under test, the engagement biasing the follower such that the interface ball engages the track under test; producing relative translation between the race and the follower along a translation axis to cause the ball to traverse the track from substantially one end to the other; monitoring the position of the follower during the traverse to produce a sequence of coordinates defining the center of the interface ball as the ball traverses the track; processing the sequence of coordinates to determine a best-fit curve for the coordinates; and comparing the coordinates with the best-fit curve to determine deviations from the best-fit curve as a measure of the surface profile of the track.
Claim 39
Independent Claim
231 words
A method for automatically gauging the surface profile of tracks of constant velocity joints; the constant velocity joints being of the type having an inner and an outer race, the races having complementary ball tracks of precise profile into which are fit drive balls compatible in size with the tracks to closely couple the inner and outer races to produce a constant velocity universal joint relationship between the inner and outer races; the method comprising the steps of: mounting one of the inner and outer races of a constant velocity joint with a track to be tested in an operative position; engaging a follower with the track by means of an interface ball of a size compatible with the track under test, the engagement biasing the follower such that the interface ball engages the track under test; producing relative translation between the race and the follower along a translation axis to cause the ball to traverse the track from substantially one end to the other; monitoring the position of the follower during the traverse to produce a sequence of coordinates defining the center of the interface ball as the ball traverses the track; processing the sequence of coordinates to determine a best-fit curve for the coordinates; and comparing the coordinates with the best-fit curve to determine deviations from the best-fit curve as a measure of the surface profile of the track.
Claim 40
Dependent Claim
67 words
The method as set forth in claim 35 wherein the constant velocity joint has a nominal contact angle for engagement between the drive balls and the tracks in normal operation, and wherein the step of engaging a follower with the track by means of an interface ball utilizes an interface ball which provides an increased nominal contact angle between the interface ball and the track under test.
Claim 41
Dependent Claim
47 words
The method as set forth in claim 36 wherein the step of engaging a follower with the track by means of an interface ball utilizes an interface ball having a relieved center to establish a minimum contact angle between the interface ball and the track under test.
Claim 42
Dependent Claim
64 words
The method as set forth in claim 35 wherein the steps of processing the sequence of coordinates to determine a best-fit curve utilizes a double regression technique which produces a first regression curve from all of the data points, selects those data points which best fit the first regression curve, and produces the best-fit curve from a second regression using the selected data points.
Claim 43
Independent Claim
248 words
A method of rebuilding constant velocity joints utilizing existing parts which have tested good and replacement parts for those which have tested bad; the constant velocity joints being of the type having an inner and an outer race, the races having complementary tracks of precise profile into which are fit drive balls compatible in size with the tracks to closely couple the inner and outer races to produce a constant velocity universal joint relationship between the inner and outer races; the method comprising the steps of: positioning one of the inner and outer races of a constant velocity joint for testing on a support to locate a track on the race for testing; providing a follower capable of movement along a deflection axis toward or away from the track under test; fitting the follower with an interface ball of compatible size and engaging said ball in the track under test as an interface between the follower and the track under test; producing relative translation between the support and the follower along a translation axis to cause the ball to translate from one end of the track under test to the other, concurrently measuring deflection of the follower along the deflection axis as a measure of the profile of the track under test; processing the profile measurements to determine if the track under test is bad or good; and rebuilding the constant velocity joint using races which have tested good and replacement parts for races which have tested bad.
Claim 44
Independent Claim
248 words
A method of rebuilding constant velocity joints utilizing existing parts which have tested good and replacement parts for those which have tested bad; the constant velocity joints being of the type having an inner and an outer race, the races having complementary tracks of precise profile into which are fit drive balls compatible in size with the tracks to closely couple the inner and outer races to produce a constant velocity universal joint relationship between the inner and outer races; the method comprising the steps of: positioning one of the inner and outer races of a constant velocity joint for testing on a support to locate a track on the race for testing; providing a follower capable of movement along a deflection axis toward or away from the track under test; fitting the follower with an interface ball of compatible size and engaging said ball in the track under test as an interface between the follower and the track under test; producing relative translation between the support and the follower along a translation axis to cause the ball to translate from one end of the track under test to the other, concurrently measuring deflection of the follower along the deflection axis as a measure of the profile of the track under test; processing the profile measurements to determine if the track under test is bad or good; and rebuilding the constant velocity joint using races which have tested good and replacement parts for races which have tested bad.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-10-15 | 2000-04-15 | 2000-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-10-15 | 2004-04-15 | 2004-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-10-15 | 2008-04-15 | 2008-10-15 | $7700.00 | Window Closed / Lapsed |