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Lg»? #bawfiafigfi a un. t- »u;.‘ ‘ ANSTATEU :ll llllllllllllllllllllllllllllll 100293902 1340 This is to certify that the thesis entitled Design and Implementation of a Transducer to Measure the Cross-sectional Dimensions of Bearing Raceways presented by Kristin Beth Zimmerman has been accepted towards fulfillment of the requirements for Masters Mechanics degree in Aflm /Major professor Au ust 2, 1990 Date 3 0-7639 MS U is an Affirmative Action/Equal Opportunity Institution LIBRARY ‘ Mlchlgan State Unlverslty l PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. DATE DUE DATE DUE DATE DUE l__l_____ fiF—j MSU I. An Affirmative Action/Equal Opportunity Institution ' chS-o: DESIGN AND IMPLEMENTATION OF A TRANSDUCER TO MEASURE THE CROSS-SECTIONAL DIMENSIONS OF BEARING RACEWAYS By Kristin Beth Zimmerman A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Metallurgy, Mechanics, and Material Science 1990 ABSTRACT DESIGN AND IMPLEMENTATION OF TRANSDUCER TO MEASURE THE CROSS-SECTIONAL DIMENSIONS OF BEARING RACEWAYS By Kristin Beth Zimmerman The cross-sectional dimensions of a 45" biangular roller bearing race cavity is measured to determine the proper roller size. Measurement is conducted by using a resistance strain gage based transducer. The transducer indicates the cross-sectional dimensions of the raceway, and this analog/digital information is fed into a computer program that generates the dimensions for a properly fitting roller for the bearing. The transducer uses the deflection of four cantilever beams to detect the cross-sectional dimensions of the bearing cavity. This transducer is capable of measuring dimensions on the order of one micro-inch or less. This thesis is dedicated to my parents. ACKNOWLEDGEMENTS I would like to thank Kaydon Corporation for offering this very intrigueing research project and I owe my utmost gratitude and respect to my advisor, Dr. Gary Cloud, for his time, patience, and faith in me during this endeavor. ii TABLE OF CONTENTS 1. LIST OF TABLES ........................................ v1 2. LIST OF FIGURES ...................................... vii 3. INTRODUCTION 1. THE PHYSICAL MEASUREMENT PROBLEM ..................... 1 II. METHODS EVALUATED FOR DISPLACEMENT MEASUREMENT ....... 3 A. Optical Methods .................................. 4 B. Eddy Current Probe ............................... 6 C. Load Cell ........................................ 7 D. Electrical Resistance Strain Gages ............... 7 E. Measurement Techniques Used In Industry .......... 8 III. SUMMARY .............................................. ll 4. DESIGN AND RESULTS iii I. FINAL DESIGN ........................................ 12 II. EXPERIMENTAL SETUP .................................. 12 III. TRANSDUCER CONSTRUCTION ............................. 17 IV. THEORETICAL STRAIN CALCULATION ...................... 20 V. CALIBRATION PROCEDURE ............................... 24 VI. COMPUTER PROGRAM - PHYSICAL SETUP ................... 30 VII. COMPUTER CALIBRATION SUBROUTINE ..................... 32 VIII. EXPERIMENTAL PROCEDURE .............................. 34 IX. SUMMARY ............................................. 43 5. DISCUSSION AND CONCLUSIONS I. Experimental Results ................................ 44 II. Further Study/Recommendations ....................... 46 6. APPENDICES APPENDIX A iv 7. I. HISTORICAL BACKGROUND ON ELECTRICAL RSG'S ........... 48 A. Definition of Strain/How it Relates to Displacement .................................... 48 B. Properties of RSG's ............................. 50 C. Types of Strain Gages ........................... 53 II. PERFORMANCE CHARACTERISTICS OF ELECTRICAL RSG'S ..... 54 APPENDIX B COMPUTER CODE - ATARI BASIC ..................... 57 BIBLIOGRAPHY .......................................... 63 LIST OF TABLES 2.1 Comparison of sensitivity, load, and displacement...23 2.2 Sensitivity Calibration ............................. 28 2.3 Data from sample run ................................ 42 vi CHAPTER 1 FIGURE CHAPTER 2 FIGURE FIGURE FIGURE FIGURE FIGURE FIGURE FIGURE FIGURE LIST OF FIGURES Schematic of optical measuring devices ..... 5 Preliminary designs after which the final design was modeled ........................ l3 Transducer final design ................... l4 Schematic showing experimental setup ...... 15 Placement of 1000 ohm RSG's on the two sets of cantilever beams .................. l8 Wheatstone bridge circuit with compensating wire hook-up scheme ....................... l9 Cantilever beam model ..................... 20 Micrometer/Calibration apparatus .......... 25 Calibration curve ......................... 29 vii FIGURE 2.9: FIGURE 2.10: FIGURE 2.11: FIGURE 2.12: APPENDICES: FIGURE A.1: FIGURE A.2: Y deflection shown for preloaded max cantilever beams .......................... 35 Transducer placement along centerline of bearing raceway cavity .................... 37 Design showing the flexibility and adaptibality of the transducer's measuring pads ........................... 139 Plot showing data from sample test ........ 42 Strain measurement over a short line segment of length 10: (a) before deformation; (b) after deformation [5] ..................... 49 Apparent strain as a function of temperature for an advance alloy temperature compensated strain gage mounted on a specimen having a matching temperature coefficient of expansion [5] ............................. 56 viii CHAPTER 1 INTRODUCTION I. THE PHYSICAL MEASUREMENT PROBLEM During the evolution.of'roller and ball bearings, the necessity for accurately measuring the cross-sectional dimensions of bearing raceways to determine the proper roller/ball size has arisen. Many techniques to solve this problem have been developed in the past, but they were only able to measure, with 1/1000" precision, the raceway of bearings less than approximately 24 inches in diameter. Measuring larger bearings with l/1000" precision has not yet been possible. The manufacturing process for most large—diameter bearings is very labor/time intensive because of the precision required for close running tolerances between rolling elements and their matching inner and outer rings. Therefore, a method needs to be established to cut assembly time by at least a factor of two. This trial and error assembly-time problem can be solved by developing a measurement tool that indicates, exactly, the correct cross- sectional dimensions of the bearing race cavity. This dimensional measurement can then be used to determine the proper roller/ball size. To begin, the project's design criteria must be established, and a measurement tool must then be designed to meet these criteria. The design criteria for the measurement device were governed by the necessity for it to: 1. be a differential method of measurement; 2. be unaffected by the presence of the clearance groove machined into the raceway; 3. indicate small axial and radial misalignments between the two rings taken as a pair; 4. be user-friendly for appropriate use on the "shop floor" and require minimum time on any given set of rings; 5. yield a continuous record of measurement and indicate any deviations from raceway cross-section to give a first approximation to actual cross-section; 6. accommodate different raceway configurations, for example: (i) biangular roller, (ii) 4 point contact, (iii) angular contact thrust; 7. achieve the proper balance between sensitivity and range; 8. indicate on a read-out device, such as a computer, the proper roller and/or ball size for the particular bearing measured; 9. be cost effective. These nine design criteria have been taken into account, and the solution lies in maintaining the aforementioned criteria in a measurement tool design. Section II compares four potentially feasible techniques for measuring dimensional quantities. II. METHODS EVALUATED FOR DISPLACEMENT MEASUREMENT Experimentalists are always challenged to find simple but accurate techniques for dimensional measurement. Such techniques include optical and mechanical methods as well as resistance strain gage devices. Some potentially suitable methods, such as optical, mechanical, and electrical measurement devices are described below; and they are evaluated against a few measurement techniques used in industry. A. Optical Methods For this particular problem, the optical methods considered were fiber optics and CCD (charged coupled device) arrays. In this application, the fiber optic measures dimensions by indicating the change in the fiber's radii as it traverses the surface being measured, while a CCD image sensor array measures displacement by indicating the variation in optical mismatch along a planar grid pattern [1]. Schematics of two such devices are shown in Fig. (1.1). Both of these methods are capable of measuring with considerable accuracy and sensitivity, but they have drawbacks in reproducibility of data. Many inconsistencies are incurred during the location of a datum or reference position for data collection. Therefore, both the fiber optic and CCD array fail items 1, 2 and 6 of the design R FIBER cipnc A V'— .. “w new" 0‘ CCD ARRAY 191192. nmrcnon or TRAVEL I j c——-. \.‘\‘\‘\ Figure 1.1: Schematic of optical measuring devices. criteria. An optical method might work for this type of measurement problem, but with these drawbacks, attention was diverted to other methods. B. Eddy Current Probe The eddy current probe is another measuring device option. This probe emits a magnetic field which, when placed a runninal distance from the target, induces a current flow on the surface and within the target. Because this induced current creates a circular pattern, it is called an eddy current. It is this current that contains information about the contour of the target's surface and distance variations from the probe's reference position [2] . This device is unaffected by lubricants in the bearing raceway, but one drawback is that it is not easily adapted to analyzing different (ie. rounded or arched), raceway configurations. The eddy probe is capable of exibiting sufficient sensitivity and range for accurate measurement, but again, it would only be able to analyze the biangular race configuration. Therefore, the eddy probe fails items 2 and 6 of the design criteria. C. Load Cell Currently, a module housing a load cell is being created. The load cell is a force measuring device [3]. Each contact surface (in this case, the walls of the race cavity) creates different forces within the load cell; and any variances in force are recorded as displacement. A reference is established and successive readings are taken and compared differentially to that reference as the probe traverses the bearing raceway. This device has the potential of satisfying all but item 9 of the design criteria. Manufactured load cells cost approximately $400.00 each, and.two would be needed for each transduceru Preliminary tests of a load cell device in the bearing cavity revealed sensitivities in a range from (0.30 to 0.35 mv/inch displacement). This approach was not pursued further as it seemed inferior to and much more expensive than the RSG transducer. D. Electrical Resistance Strain Gages (RSG'S) An electrical resistance strain gage (RSG), in elementary terms, is a device containing a foil grid (resistor). When the surface that the strain gage is bonded to deforms, then a change in resistance is recorded. This is the basic idea behind the resistance strain gage. As to application, RSG's are frequently used to measure strain, and displacement, and are incorporated as sensors in transducers designed to measure such quantities as load, torque, pressure, and acceleration. An RSG device, when properly designed, should satisfy all of the design criteria so attention was concentrated on this approach. Since an RSG transducer was designed to evaluate the bearing measurement problem, it is essential to describe how an RSG transducer works and why it was used. An in- depth description on the historical background of RSG's is contained in the Appendix A, along with an illustrative procedure on the definition of strain and how it relates to displacement. E. Measurement Techniques Used in Industry Among the reasons to create a means of accurately measuring bearing raceways is that both the inner and outer bearing rings need to match one another in tolerance so as to glide smoothly across the rollers or balls separating them. Currently, very accurate methods are being used to evaluate bearings that are less than 24 inches in diameter, but the problem lies in the eccentricities and out-of—roundness of larger bearings. Listed below are various methods used by industry to evaluate the measurement of large bearings [4]. Dimensional Measurement 1. Bendix Auto - DC Measuring Machine - diametral internal clearance 2. Bendix Cordax - deviation from true position or shape 3. Bendix Proficorder 4. Bendix Indicorder 5. Rank Tallycentric - deviation from true circle 6. Rank Precision Vertical Slide (with rotary surface plate) - deviation from squareness and cylindricity 7. Federal Comparator - 2-point size calibration, 32/1 scale (for master ring diameter calibration) 8. Rank Tallysurf - deviation from true radius (transverse surface finish) 9. Bendix Wavometer - raceway waviness (dynamic) 10 Note that even though these evaluation methods are used, there still exists a trial and error phase during the insertion of rollers/balls into the bearing raceway. This phase is very time consuming, since the procedure requires that the rolling elements and spacers (188 rollers and approx. 188 spacers in a 45" bearing) be inserted, one-by- one, through the bearing's loading plug until the bearing race is fully loaded. After the bearing is loaded, it is tested using the following criteria [4]: Testing Criteria 1. The ring's diametral preload is recorded and the tolerance between mating rings is checked to match (+ 0.0001-0.0005 inches). 2. The breakaway torque, which is the force required to rotate the inner ring while the outer ring remains stationary, is measured. This measurement must yield 20-100 ft-lbs when checked at 6 equally spaced locations on the inner race, again, while the outer race is stationary. If this measurement is out-of- range, then an adjustment must be made by 11 changing either the roller size or spacer size. 3. If neither requirement is met, then the bearing must be either re-machined or scrapped. The testing procedure, listed above for the 45" biangular roller bearing suggests that this process is extremely time intensive. Therefore, finding a means of expediting the "process" is critical. III. SUMMARY The purpose of this study is to determine whether or not a measurement tool can be designed to measure, with more precision than l/lOOO", the cross-sectional dimensions of a bearing race cavity. This measurement is critical in determining the proper roller/ball size to use in each bearing assembly. Now the discussion leads to the development of an actual displacement transducer design. Other methods were evaluated, and each had their own strengths, but the transducer satisfied more of the design criteria and 'became the chosen approach to solving this unique measurement problem. 12 CHAPTER 2 DESIGN AND RESULTS I. FINAL DESIGN The stages leading to the final design evolved from consideration of several potential models, some of which are featured in Fig. (2.1). Also, a large number of the design criteria previously mentioned in Chapter 1 were taken into considerathnn Specifically, the transducer is designed with four cantilever beams (containing 2 resistance strain gages each) mounted onto a cube, Fig. (2.2), and the resistance strain gages respond to the deflection of the beams. The following section outlines the experimental measurement setup and measurement scheme, while the remainder of the chapter discribes each component of the scheme. II. EXPERIMENTAL SETUP The experimental setup is shown, schematically, in Fig. (2.3). The transducer, which is located inside the bearing, 13 .voaocoa no: onhuououm Assam any news} uoumo unwauov huoaaaaaoum "~.N ounwwh V / / Ir .2. o a 555. . some / / // / / / ”.50. d>§_..llll till: 0 UV .3 E 52.8 \\\\\\\ Sm: .siOx e monmmm NDUDQMde: >m¢z§3wmm l4 .uoosvmcouu on» no cwamov Hanan ”N.N Gunman MMIUZHQZDHMZMZHQ md med . . J t mg 1 L , mo _. _ ssxadm gm. 7/ fix?» l'qllmod 020.3 zozouuun OH.O .. t. lune a anew“ @ 35o EU>UJHPZ(U mxnmeo umd. Ema 23 MF¢I_I._ [llomd 22:28 25 223:“. Illrlmmd mmfizzem¢z$m§z§3¢-mmajsmmzz 15 .a:-uom Houcoawuoaxo waaaonm oauoaonom amt/San. mDCZDz\> Na Io mmmmm Passe n\( QMHDQZDU mmhkagd ”MN dawn oszqwm mwljam 2. Io «(43024.5 IUZH we «532$: 29: dzzoHaucoo no open 030 05» co n.0mm afio coca mo ucoaoooam ”Q.N ounwwm oTo 3%) H23 mzZHzB me dzzfis uME”? ma; 25 n O . ® @ _ _O @ - 3mm 2. Juzzcro 0 ® @ ® @ Mtowm LU ZDHFQUDJ 19 WHEATSTUNE BRIDGE CIRCUIT (1 PER CHANNEL) 1,4,9,18 3,5,11,13 6,8,14,16 NflTEiEAD VIRE HOOK-UPS ARE LISIED AI EACH NUDE Figure 2.5: Wheatstone bridge circuit with compensating wire hook-up scheme. 20 IV. THEORETICAL STRAIN CALCULATION Verification of the target sensitivity begins with the calculation of strain (based on beam theory) and by the equation: 6 - My/EI (2.1) where: I - moment of inertia (bh3/12) y - distance from centroid (0.5 * a) M - moment arm (force * distance) E - Young's Modulus (28 x 10E6 psi) stainless steel The cantilever beam parameters are found in the Fig.(2.6) below: 21 Values for a, b, h, and L are: b - 0.10 inch a,h - 0.020 inch L - 0.225 inch To calculate I and y let: I - bh3/12 - (0.10)(0.02)3/12 - 6.67 x 10E-8 in4 y = 0.5 (0.02) - 0.01 in Now that each component is calculated, strain can be determined as: e = My/EI - Force [(0,225) (0.01)]/[(6.67 x lOE-8) *(28 x10E6)] - 1205 p strain * Force (2.2) The calculation for displacement can now be determined. 22 Let displacement Y - -FL3/ 3EI max (2.3) where: F - load (pounds) L - lever arm In this sample calculation let F - 0.008299 pounds, so: Ymax - -(0.008299) (0.225)/3(EI) - 17 p inch This calculation demonstrates that the amount of maximum deflection (Ymax) at the end of one cantilever beam equals 17 micro-inch at a load of 0.0083 lbs. This deflection 'value falls into the strain range of 10-20 micro-strain and verifies that by using RSG's in a cantilever beam configuration ample sensitivity is achieved. Table (2.1) shows hOW'the 10-20 micro-strain sensitivity might be achieved.by'inserting particular values of force (column 1, Table (2.1)) into equation (2.3). Theoretically, the sensitivity was proven to fall in a range from 10-20 micro-strain. It now remains essential to calibrate and verify, experimentally, that the RSG transducer achieves a calibrated sensitivity comparable to 23 633338 53335.8 "a.“ «San. lam... lflm... g IMMI .ImMI dmwflm..- INA... INMI: a .04... . IMM: mums... IN... 1mm... ass. IWIHII Iflml. .mlmmmd..- Imus] JIM! a .IHIHI. IWJI g Imml. INN! g 9602 223m €510.02 wezuzmufiawa mo: 95.. CV Hzmzmuqmmma m: w>:¢u_m~_ zficmhmamgz omlofi 20mm >C>Htmzmm 24 the theoretical sensitivity. The next section describes this calibration procedure. V. CALIBRATION PROCEDURE To determine, experimentally, the sensitivity of the RSG transducer, a calibration scheme was established by inserting the transducer into an X-Y micrometer apparatus that separately induced compressive loads onto each set of cantilever beams, Fig. (2.7). As each set of beams was deflected along both the X and Y axes, the displacement in the beams was recorded in terms of a voltage difference across each set of RSG hookup wires. Therefore, two corresponding values of voltage and displacment were recorded. These two corresponding values establish points on a calibration curve, and the slope of the curve indicates the sensitivity of the system. The preceding calibration also includes calibrating each channel. The calibration constant to convert'duaudcro- strain or milli-voltage readings to readings of displacement was simply adjusted on each indicator by rotating the span dial. Utilization of the calibration constants will be outlined further in section IV. 25 .msuouomao cowuounaaoo\uouoaouoaz uh.N shaman .mmemteso> are 2D assessw_= use wasaesg> oz_ozoammmmau are gza ”22mm em>um_ez¢u.ao sum as as 255253 235. e use: “=2 e a x as Q52 MEEEQ,‘ $3283: TX 2.5; .368 $55.; me< > 352:? ME 5 mmuammzéh ME :9: mum; H23 2 0258: m3: 2?. x 26 The transducer was now calibrated for differential measurement, but it still remained necessary to develop a means for obtaining the absolute calibration measurement of the bearing cavity. This can be done in any number of ways. The most effective approach is to machine at least two different biangular cavity configurations with dimensions varying slightly above and below the known range of the machined cavity size. For example, the bearing cavity is nominally machined with a cross-sectional dimension of (0.625 +/- 0.0002) inches; it is necessary to machine two other cavity configurations with dimensions of (0.625 + 0.0002 and 0.625 - 0.0002) inches, respectively. An Optical Comparator or Jo-Blocks can be used to verify the two dimensions. Note that the precision of Jo-Blocks is on the order of one micro-inch, while the Optical Comparator can achieve only 0.0001" precision. Now plot the two cavity configurations. This results in a calibration curve evaluating displacement and voltage. The slope of the calibration curve is then used as the zero reference calibration constant. This zero reference is used in determining the absolute bearing cavity dimension. Note that the transducer must remain linear within this calibration range. A sample case is illustrated in 27 Table (2.2) and Fig (2.8). The sensitivity of the system is found to be 6.1 mv/0.0001" displacement for channel #1 and 2.5 mv/0.0001" displacement for channel #2. The difference between these two sensitivity values is caused by the dissimilar placement of each RSG on the top and bottom sides of the cantilever beams. This calibration technique establishes the absolute size of the bearing cavity. Now the deflection values recorded off’ the transducer's two sets of cantilever beams, as the transducer traverses the race cavity, can be subtracted from the absolute cross-section of the cavity. As a check, this calibration test should be done both before and after the actual measurement has taken place. A computer subroutine was written to handle the calibration. measurements for absolute dimensions, as well as to compare the incoming measurements from the transducer. An average of the two sets of measurements is calculated, separated from the absolute cavity size, and this determines the correct roller/ball size to be used. Iflxflnmtely, a roller size with a clearance fit throughout the circumference of the bearing is sought. 28 CALIEZATION ME Reference Mperature : 72 F Excitation Voltage : 5 volts dc RSG ID : SK-O9-060CD-10C gage factor . : 2.11+/- 0.3% at 24 degrees C Ohms per use : 1000 =/- 0.3% at 24 c Transducer sensitivity : channel #1 6.1 mv per 0.0001 inch disp. channel #2 Range 2.5 mv per 0.0001 inch disp. 0-0.004 indies displ. mm 2.2: Sensitivity Calibration 29 CHANNEL III SENSIIIVITY = 6.1 nv/OIIOOI INCH DISPLACEMENT CHANNEL Ila SENSITIVITY = 2.5 I'IV/IIIIIIIII INCH DISPLACEMENI SENSITIVITY/CALIBRATION CURVE 030 029 028 027 026 SLUPE: ti (CHANNEL III) VULIACE 0.25 SLUPE : 35 (CHANNEL I18) 024 023 022 021 0.00 "I'll" ",IIIHIWWWWWWHI mun" Illungsnmm 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0(x10-3). DISPLACEMENT (INCHES) llllIIIIIIIIIIIIIIIIIlllIllllIllllIllllIlIllIIIllIIlllIlIlIIlIllIllIlIllllIllIIIIIIIIIIIIIIIIIIIIII FIGURE 2.8: Calibration Curve 30 The following section outlines the physical setup of the computer program and describes the communication process between the transducer and the computer. VI. COMPUTER PROGRAM PHYSICAL SETUP The computer program is listed in Appendix B, but an explanation of the physical set-up is pertinent. The strain indicators displayed displacement in each set of beams, via channels #1 and #2, therefore an interface was necessary to relay this information to the computer. This communication was achieved by hooking two cables (positive and negative) into each indicator's voltage output jack and connecting them to a Starbuck A/D converter [7]. Two channels were evaluated, so two separate channels were used on the A/D converter. The voltage was checked during the calibration.process and was offset by a factor of 1 (volt) to insure a.positive voltage reading for all displacements. The Starbuck A/D converter required positive voltage inputs. Next, a single hook-up was made from the A/D converter to an R8232 interface (port 1). This hook-up enabled communication between computer, A/D converter, plotter, and 31 printer. Only one communication port was used, and the two channels remained as separate strings of information; so a comparison between the two sets of beams could be made throughout the investigation. As the voltage information was read into the computer it became necessary to convert this number to a tangible displacement and ultimately into the actual cross-sectional dimension of the bearing raceway. (UniS‘was done using the calibration factors and can be seen in the program as, "indicated voltage input converted to:" 1. indicated displacement 2. indicated diagonal channel size 3. actual diagonal channel size * 4. correct roller/ball size to use in the bearing. The analog input of voltage to the converter is computer keyboard activated, and up to 100 data points along the bearing circumference can be analyzed in a single run. As a recommendation for further study, it would be advantageous to create a randomized continuous sampling of points along 360 degrees of the bearing. 32 VII. COMPUTER CALIBRATION SUBROUTINE 'To expand on the computer's contribution to the calibration calculation, an example procedure follows: Step 1 - record dimensions and voltages for each calibration cavity. Disks 1,2 refer to calibration cavity disks of a particular size, while voltages 1,2 refer to the corresponding voltages created by inserting the transducer into both disk 1 and 2; i.e. disk 1 0.624" [001] disk 2 - 0.626" [002] voltage 1 0.392 volts [CV1] voltage 2 0.267 volts [CV2] Step 2 - calculate the slope of the voltage vs displacement curve; i.e. CV2 - CV1 51°pe ' 002 - 001 - 62.5 v/inch 33 Step 3 - insert the transducer into the bearing and take a voltage reading; i.e. average voltage [AV] - 0.331 v Step 4 - calculate the interpolation increment; i.e. increment [INC] - AV - CV2 - 0.064 Step 5 - calculate the absolute dimension of the cavity; i.e. absolute dimension [AD] - disk2 - (inc/slope) = 0.624976" This procedure is incorporated into the computer program listed in Appendix B. Section VIII describes the experimental procedure and illustrates how the design criteria is satisfied by the RSG transducer. 34 VIII . EXPERIMENTAL PROCEDURE Before the transducer is inserted into the bearing, the geometry of the bearing cavity must be established. This is done by inserting three balls, via the loading plug hole, into the gap between the bearing's mating rings. Each ball is then positioned every 120 degrees to allow the inner ring to rotate freely with respect to the outer ring. At this stage, the bearing cavity is ready to receive the transducer. The transducer is inserted, via the loading plug hole, into the bearing. After insertion, the transducer traverses the bearing raceway, via rotating the inner race manually with respect to the outer race, and measures the cross-sectional variation within the dimensions of the cavity by indicating deflection in each set of cantilever beams. It is worth noting again that the cantilever beams located on the transducer were preloaded by the walls of the race cavity to ensure measuring contact at all times. An illustration of the preload configuration is found in Fig. (2.9). The sixteen wires from the transducer's RSG'S were then fed through the clearance gap at the top of the race cavity and were hooked into their respective channel indicators. 5 . memos no>03ucoo cocooaéua you £65m 60.300530 Roar "TN can»: MJHLDMQ HIDHQ \\\~mmmmmm\\ ‘ . 5:5: was. Emacs .2 A , > UhC>¢u modm no MISS.) mzw1:._.zoo hoaoocu wcauoon Mo ocaauoucoo wcoao ucoaoooaa Hoosvmcoua “OH.N shaman / me dzzaa . I... Is. sass. e masses a assess b\ I? 090. . I \ s 522% e. \ 25:32,me 1:3 238$. ozESm .5 2255-3me 38 Able to measure relative out-of—roundness for the rings as well as radial and axial misalignment between the two rings. In preliminary readings from the transducer, it became apparent that if a reading was taken directly next to one of the three balls, located every 120 degrees, then misalignment between rings virtually cancelled. This must mean that the 5/8" + 0.001 size and tolerance on each ball is sufficient to take up most of the slack or gap (misalignment) existing in the bearing race cavity. Misalignment/out-of-roundness was apparent at arbitrary distances from each of the raceway balls. Able to accommodate different raceway configurations (i) biangular roller, (ii) 4 point contact, and (iii) angular contact thrust. This feature is built into the transducer design and is located at the end of each of the cantilever beams, Fig. (2.11). Each beam achieves a preloaded (raceway flat) contact, at the extreme ends of the beams. Kel-F (a common flourocarbon) was selected as the material used at the contact surface because of its very low friction factor. Kel-F insured an easy, gliding, measuring surface between the bearing race and the transducer. .noom meausmooa m.uoo:omcouu 0;» mo huaaaneueooo can auaaunaxoam one mafiaonm swamoa "HH.N shaman madam. tm\m q mm: 205mm muuammzxamfi Ema 23 zszsz was”. 36 zszqu ”1.55%; ”1.55%; q A .._I 9 mxnmfio NXDNGO 3 UN}. 1 - umq / . _IILIom.o ems sense. «58% uses «as. «2.823 e: we: 285. «E ”2.: 2st: made FZMZMWSMQMZ LB ZDHHQQHLHQDZ 40 The shape or configuration of these pads can be changed to accommodate the different raceway configurations and dimensions; therefore, a common transducer "module" can be created for each "nominal" raceway diameter. For example, if 1" diameter balls are used in a particular raceway, then a transducer can be used with a l" radial pad configuration. D. Able to achieve a proper balance between sensitivity and range. Qualitatively, the sensitivity must allow the detection of small dimensional changes within the comparatively large cross-sectional dimension of the bearing race cavity. Preliminary calculations of sensitivity revealed a proper balance of sensitivity and range by achieving a range of 10-20 micro-strain for beam deflections of 1/1000". A sample test was conducted to verify the experimental procedure, see Table (2.3), and a plot was generated from the data; this is shown in Fig. (2.12). Note the location of the loading plug along each curve. At this location there appears to be a relaxation in both sets of beams which indicates that this location could possibly be used as a reference for initial calibration of the transducer. 41 .2.~ 8:»: 5a: :32. 352. FWM... MJHZZQW HUM {F.QQ eeofi. .6?“ 3953 2.5 39.5 coo—ea euauoe euoa ”n.N canon. 331 IIILEBmee .0. 00336.6 ImMNImMgI IDI namind emhmwed INN 0.00200 oemmlmed: - .NI vmwzmd Momnmed IWI 3005.0 «mlesmed IMI mu 4mzz¢Iu IIMNAAANIQI IddeMfldI IWI nvvzmd vebmmed .Wl «ended Embed TM. Mmmzmd auwmmud .4. meeznd ennmmed .mwl 30:00 mmemMed lmI mums—ed evmmmed IM. smomamo chewed INI doom—m6 Seemed Tm: @060 000.0... M... s dzzsa emomand neovmed t 3030.0 mnmmmed INN Momzmd moemmed INI seIeSmd ensmmed 1m. uzfimuhzwo to 323mg uNHm $2245 .ZzouSn .332 MHZHDQ 42 .ueou canade scum dude wcaaose uoam “NH.N unswum AZ”: .5 BBQ 32:5 .5 a + _. e w w e .. w w .. ma Juzz"Y" THEN GRAPHICS 0:END 515 I=1:J=1:X=9:C=1 520 GRAPHICS 7:OOLOR 1 522 GOTO 1100 528 GOTO 698 529 GOTO 502 698 REM "PLOT OF CHANNEL #1" 700 OOIOR c 702 INPUT 120 THEN z=4 Q=N:IFQ>C*20 THEN Q=C*20 Ito ? #2; "C";C-1 Y=80*’IUI‘((C-1)*20 +1,1) ? #2; "M";50 + Y1; ",";‘I‘ POR L=(C-1)*20 +1 TO Q:POR I=1 TO 10 Y = 80*‘IUI' (L,I) ? #2;"D";50 + Y;",";T T = T + 2:? T, NEXT IzNEXI‘ L c = C + 1:IF ((C-1) *20)-N<0 TEEN 1252 CTDSE #2:RETURN GOIO 1599 ? "WHRI'TYPE OF BEARING IS BEING ANALYZED?" ? "I! ? "CHOOSE THE BEARING TYPE" ? "ll 9,35:DRAWTO 159,35 59,31:DRAWIO 59,39 7,45:DRAWIO 11,45 7,55:DRAWTO 11,55 7,65:DRAWTO 11,65 7,25:DRAWIO 11,25 7,15:DRAWTO 11,15 7,5:DRAWIO 11,5 19,34:DRAWIO 19,36 29,34:DRAWID 29,36 39,34:DRAWTO 39,36 49,34:DRAWTO 49,36 59,34:DRAWIO 59,36 69,34:DRAWTO 69,36 79,34:13RAWIO 79,36 89,34:DRAWTO 89,36 99,34:DRAWTO 99,36 109,34:DRAWLO 109,36 61 1452 ? "HIE = BIANGULAR ELIER BEARING" 1453 ? "FPC = 4 POINT MCI BEARING" 1454 ? "FPR = 4 POINT RADIAL (DNI'ACI' BEARING" 1455 ? "ACI' = ANGUIAR CDNI‘ACI‘ THHJST BEARING" 1456 ? "" 1457 ? "" 1497 INPUT C5 1499 IF C$ = "BIB" THEN ? "'IHE AWESIS OF A BIANGUIAR ROLLER BEARDIG FOLILMS" 1500 GOIO 8 1501 ? "" 1502 IF GS = "FPC" THEN ? "THE ANALYSIS OF A 4 POINT CDN'I'ACI‘ BEARING 170110178" 1503 G010 9 1504 ? "" 1520 IF C$ = "I'M?" THEN ? "THE ANALXSIS OF A 4 POINT RADIAL CDN'IACI' BEARING FOLICNS" 1522 GCIO 10 1523 ? "" 1530 IF GS = "ACI‘" THEN ? "THE ANALYSIS OF AN ANGHAR CDN'I‘ACI‘ ‘IHHJST BEARING FOLILWS" 1532 0010 12 1599 RETURN 1600 ? "NOT AVAILABLE"; GOIO 1799 1799 RETURN 1800 ? "NOI' AVAIABIE"; 6010 2099 2099 RETURN 2200 "******************************************H 2300 "******************************************N 2400 " CALIBRATION W" 2450 "******************************************fl 2455 fl******************************************" 2500 "n 2600 ? "" 3000 DIMCV1(10),cv2(10),CD1(10),CD2(10),DR1(10),DR2(10), SIP(10) .AV(10) .INC(10) .AV2(10) .SLP$(1) .AD$(1) .AV$(1) 3005 ? "" 3006 ? "" 3007 ? "THE GALIBRATION OONSEANTS FUR ABSOLUTE DIMENSIONS OF THE BEARING RACEWAY CAVITY.ARE.AS FOLDOWS:" 3008 ? "" 3009 ? "" 3010 ? "WHAT ARE THE DIMESIONS OF THE Two CALIBRATON CAVTTIES?":INPUT DKI:? DK1:? "DISK #1 = 0.6248" 3011 ? "" 3012 ? "" 3015 INPUT DK2: ? DK2: ? "DISK #2 = 0.6252" 3016 ? "" 3017 ? "" 0" 0‘) 0‘) 0‘) 0‘) 0‘) 62 3020 ? "WHAT Is THE WLTAGE AND DISPLACEMENT ASSOCIATED WITH BOTH OF’THE CALIBRATION CAVTTTES?" 3021 REM 3022 ? "" 3023 ? "VOLTAGE FROM DISK #1=":INPUT CV1:? cm 3024 REM .. 3025 ? "VOLTAGE PROM DISK #2=":INPUT CV2: ? CV2 3026 REM 3027 ? "" 3030 ? "DISPLACEMENT PROM DISK #1=":INPUT (131:? C131 3031 ? "" 3032 ? "DISPLACEMENT PRLIM DISK #2=":INPUI' c132: ? C02 3033 I." 3037 REM 3038 ? "" 3040 ? "me THE SLOPE OF THE CALIBRATTON CURVE TO DETERMINE TEE ZERO REFERENCE CAIIBRATON CONSTANT" 3041 ? I". 3042 ? "" 3045 ? " SLOPE = SENSITIVITY, WHICH EQUALS ..." 3047 INPUT SLP$:SLP = (((CVl-CV2)/(CDl-CDZ)/10)):? SLP$:? "(NV/0.0001 INC}! DISPLACEMENT)" 3048 ? "" 3049 ? "" 3050? "DITERPOLATEBETWEENTMETWOVOLTAGEVALUESTOPIND 'IHE VOLTAGE VALUE FOR ABSOLUTE 0.625 +/- 0.0002 INCHES" 3051 ? "" 3053 ? "INPUT THE ABSOLUTE mm READING TRIM THE VOLTMETER:"INPUT Av: ?.AV '0 3054 ? "N 3055 ? "ABSOLUTE VOLTAGE = AV = (CV1 + (INC*(CV2-CV1)))" 3056 ? "" 3057 ? "OOMPUTE 'IHE INCREMENT (INC) FOR THE EQUATION (AV) :" 3058 ? "" 3059 INC = CV1-AV:? INC 3060 ? "" 3075 ? "THE ABSOLUTE DISPLACEMENT = (AD) AND IS COMPUTED USING THE FOLLOWING EQUATION:" 3076 ? "" 3078 ? "AD=(DK1+(INC* (DK2-DK1) ) ) " 3079 ? "" 3080 AD = (DK2-(INC*(DK2-D1c1))):? AD 3081 ? "" 3082 ? "" 3090 ? "PLUGTMECALIIJLATEDVALUEEORTHE ZEROREFERENCE DISPLACEMENT (AD) INTO THE EQUATION EOR ACTUAL DIMANSION" 3091 ? "" 3100 GOTO 13 BIBIIGERAHiY 63 BIBIICIERABIY EB and G Retioon, "Ima e Sem' Products", 910 Benicia Ave., Sunnyvale, CA 94086, 1987. Kaman Measuring Systems, 'Measurement Solutions Handbook", PO Box 7463, Colorado Springs, (1) 80933, vol. 2, 1987. Ehtran Devices Inc” "Low Profile load Cells", Errtran Bulletin flo-200 Series, 10 Washington Ave. , Fairfield, NJ 07006, 1986. "Perfonnanoe Brochure", Kaydon Corporation, Muskegon, MI, 1988. mimental Stresé Analfiis, Dally, J .W. and Riley, W.F., MoGraw Hill, 2’nd edition, 1978, diapter 6, pp. 153-199. Ibid, chapter 8, pp. 212-266, chapter 10, pp. 318-333. "Starbuck 8232 Data m'sition and Control m, mtions Manna ", Starbuck Data Company, PO Box 24, Newton, MA 02162, 1983. MICHIGAN STATE UNIV. ll‘WWWWII"WllHlmlmll 3129300904