1、01FTM4How to Inspect Large Cylindrical GearsWith an Outside Diameter of More Than40 Inchesby: G. Mikoleizig, Klingelnberg Shne GmbHTECHNICAL PAPERAmerican Gear ManufacturersAssociationHow to Inspect Large Cylindrical Gears With anOutside Diameter of More Than 40 InchesGenter Mikoleizig, Klingelnberg
2、 Shne GmbHThestatementsandopinionscontainedhereinarethoseoftheauthorandshouldnotbeconstruedasanofficialactionoropinion of the American Gear Manufacturers Association.AbstractFollowing the general trend, increasingly high quality requirements are also being made on large gears.Examplesincludegearsfor
3、largeearthmovers, shipsgears, cementmills, rollingmilldrivesand thelatestwindpowergears. The demands for a smaller structural volume with simultaneously higher power and lower noise emission areparticularly clear here.Approaching these limits, combined with the refined calculation methods for design
4、ing a gear, demands preciseinspectionoftherequiredflankgeometryonthegearsused,inordertoensurethenecessaryfunctionalsafetyunderload.Thismeansthatclearlydefinedcorrectionstothegearflankssuchasdepthcrowningandcrowning,rootandtiprelief,aswell as lead corrections, must be specifically producible and veri
5、fiable.Thearticleshowsthedesignandfunctionoftherelevantmachinesusedforindividualerrormeasurement,i.e.leadandprofile form, as well as gear pitch and runout.A distinction is made here between different types of inspection machines between stationary, CNC-controlled gearmeasuring centers for checking a
6、ll relevant parameters on gears, and transportable equipment for checking individualparametersdirectlyonthegearcuttingorgeargrindingmachine.Importantpointssuchaspreparatorymeasuresbeforeameasurement, including workpiece axial position definition, pre-alignment of the system etc. are also taken intoa
7、ccount here.Following on from this, practical measurement examples with evaluation examples, measurement times etc. are alsodescribed, including the conditions when inspecting large internal gears.Thearticleisroundedoffbyadescriptionofintegratedmeasuringdevicesongearprocessingmachines,aswellastheira
8、dvantages and disadvantages.CopyrightGe32001American Gear Manufacturers Association1500 King Street, Suite 201Alexandria, Virginia, 22314October, 2001ISBN: 1-55589-783-51HOW TO INSPECT LARGE CYLINDRICAL GEARSWITH AN OUTSIDE DIAMETER OF MORE THAN 40 INCHESGuenter Mikoleizig, Dipl-Ing.Technical Manage
9、ment Inspection Machinery - Klingelnberg Soehne GmbH, Hueckeswagen, Germany1.0 IntroductionLarge cylindrical gears have been used for a verywide range of drives since the beginning of industri-alization. Due to the size of these workpieces, how-ever, it was only possible to check quality-relevantfea
10、tures on these gears to a very limited extent.In addition to simple manual inspection devices, e.g.for the determination of the individual componenterror, or mechanically controlled inspection machinesfor the definition of profile and lead deviations, largegears were almost exclusively evaluated by
11、means ofa test run with definition of the contact pattern. Officialacceptance of large gears after a test run also re-mains obligatory today in many large companies.However, modern CNC-controlled systems are avail-able today, which allow individual parameters to bechecked on large gears, thus enabli
12、ng control of themanufacturing process and subsequent production ofa quality record.The design and functioning of such systems are de-scribed in the following contribution and supple-mented with practical application examples.2.0 Basic design and function of stationarygear measuring machinesCNC-cont
13、rolled gear inspection machines for smallergears have already been successfully used in theindustry for many years. Starting from the knownmeasuring tasks of profile, lead, pitch and runout oncylindrical gears, these machines offer a much greaterdiversity of application on the basis of their techno-
14、logy. Ultimately, an extended software package is allthat is required to inspect worms and wormgears,bevel gears or even gear cutting tools such as hobs,shaving and shaper cutters.Appropriate individual error inspection machines arealso available for workpieces up to 2600 mm (102“)outer diameter.Bas
15、ically, CNC-inspection machines consist of thefollowing components: Basic machine bed with rotational axis and linearmeasuring axes CNC-control for executing measuring movementsand forming measured value Evaluation computer system for programmingmeasuring runs and evaluating measurementresults, incl
16、uding documentation via printer Evaluation software for inspecting a diverse rangeof gear-related workpieces.Figure 1 shows an overall view of a CNC-controlledinspection machine for workpieces up to 2000 mmdiameter.Figure 01: CNC-controlled gear inspection machineThe components mentioned above can b
17、e easilyidentified. The functioning of a CNC machine is com-parable to the functioning of a mechanically con-trolled inspection machine for cylindrical gear meas-urement. The generating principle of an involute isused during profile measurement. Further parameterscan also be checked on cylindrical g
18、ears by the useof coordinate movements in one or more axis.In the case of a CNC-controlled inspection machine,instead of mechanical drive elements such as rollingdisks and friction bars electronically controlled indi-vidual drives are used on the axes. The functionalinterrelationship is shown in Fig
19、ure 2. The measuringmovement for generating the involute form occursthrough a coupled movement of rotational axis C,including workpiece with the linear axis X, and themounted probe system. The coupling ratio (transmis-sion ratio) depends on the technical data of the cylin-drical gear to be inspected
20、. In addition, each axis isequipped with an M1/M2 drive motor as well as therelevant angle/length measuring system.2Figure 02: CNC-controlled profile measuring(principle)The synchronization of the movement cycle is en-sured by the CNC control. The probe system thusdirectly records the profile deviat
21、ions of the testpiece. Further representation and evaluation of themeasuring curves subsequently occurs via a PCcomputer. The inspection cycle for lead measurementon cylindrical gears is generally the same, except thatin this case a coupled measuring movement of axesC and Z (Figure 3) is executed in
22、 relation to the nomi-nal lead (base helix angle b). Depending on themeasuring task, diverse axial combinations can beimplemented, both for continuous and for individualpoint probing.Figure 03: Axes of a CNC-controlled gear inspectionmachine (example)2.1 Mechanical construction and probe systemThe b
23、asic component of an inspection machine is themachine bed, which should be designed as com-pactly and rigidly as possible, so that it can also ac-cept high workpiece weights without the overall ge-ometry being affected. Gray cast iron has provenitself as the construction material of choice, with rel
24、i-able achievement of these properties. Other materialsare also well proven.In the case of a workpiece loading above 10,000 kgin weight, as may occur with appropriate inspectionmachines, a stable bed structure alone is not suffi-cient, but a bond with a stable foundation must beproduced. A specially
25、 designed foundation is alsoimportant, in order to protect the inspection machinefrom the effects of external vibrations.The superstructures of the X, Y, Z-linear axes and theC-rotational axis are also made of cast iron, with fittedprestressed, backlash-free and highly accurate anti-friction guidewa
26、ys. In addition, the selected materialcombination guarantees a high geometrical resis-tance to the effects of temperature. In order to beable to avoid influences, fluctuations or noise whenrecording measured values, direct drives without me-chanical drive elements have successfully becomeestablished
27、, both for the rotary table (high-pole servo-motor) and for the linear axes (linear motor), in addi-tion to conventional drives, e.g. via friction gears orball screws.In order to be able to deal with large differences indiameter in the case of large cylindrical gears or gearshafts, a machine design
28、like the one shown in Figure3 and 4 is advantageous. The basic unit with X- / Y- /Z-measuring axis can be moved via an adjusting axisY as close as possible to the outer diameter of thegear to be inspected. The actual probing of the gearor defined reference surfaces can then occur via theactual Y-axi
29、s. This machine design also enables gearshafts with several gears to be inspected in amounted status at one clamping (Figure 5).Figure 04: Example of traversing paths Gearinspection machine for large workpiecesIn addition to the practice of mounting large work-pieces exclusively “unsupported“ on the
30、 rotary tableof the C-axis or in conjunction with face plates (Figure5), there is often also the requirement to mountsmaller workpieces or gear shafts between centers.In this case, an additional column with tailstock is re-quired. The column is adjusted mechanically and the3upper center can be swung
31、 to the side to facilitateworkpiece loading. As the operator must coordinateseveral activities during workpiece loading, a cable-free remote control is particularly helpful (Figure 6).Figure 05: Inspecting a drive shaft with two gearsInstead of the upper tailstock, channeled bearings orfixed stays a
32、re also sometimes used, if the clampingrange of the column is not adequate for the work-piece to be inspected.Figure 06: Upper tailstock, mechanically positionableand hinged with remote controlThe probe system provided is of particular impor-tance on a gear inspection machine. According toFigure 3,
33、this system is located at the front end of theY-axis. Three-dimensional probe systems, as shownin Figure 7, provide better prerequisites for recordingvery different functional surfaces on gear-relatedworkpieces in a single run.Measured values, as in the case of profile and leadmeasurement, are recor
34、ded on cylindrical gears byusing the X measuring axis of the probe system. Forlead measurement on cylindrical gears with a largehelix angle, or for cylindrical worms, the probing di-rection can be preselected in the X and Z plane indirectional reference to the measuring point. Thisprobing method ens
35、ures a high probing accuracy.The Y-probing direction enables e.g. root and tip cir-cle diameters to be recorded on cylindrical gears, aswell as e.g. defined reference surfaces to determinethe precise workpiece position.Figure 07: 3D-probe systemIn contrast to switching 3D-probe systems, which arepar
36、ticularly suitable for individual point probing,“measuring probe systems” are required for gearinspection for continuous measured value recording(scanning) e.g. in the case of profile and lead meas-urements. I.e. each measuring axis must have a largemeasuring path (e.g. 1 mm) and be equipped with an
37、appropriate length measuring system.In this regard a digital measuring system offers theadvantage that the signals can be processed directlyin the CNC control without conversion and the meas-uring accuracy remains constant, irrespective of themeasuring path.Another essential feature of a modern prob
38、e systemis a probe element exchange device (Figure 8). Herethe probe element is connected to a change plate.The connection to the actual probe system is pro-vided by an adapter device with high centering accu-racy. A similar device offers the advantage of probeelement exchange without recalibration,
39、 as the cali-bration data already stored in the computer system ofthe inspection machine can be used.Figure 08: Measuring probe changing deviceAlso important are the protection systems in a probesystem in the event of collision. These prevent down-times of the entire device, as well as high repairco
40、sts.When inspecting large gears, extended probe rodsmay be required to cover the entire gear. A typical4example of this is the inspection of large internalgears (Figure 9) for wind power gears. In the exam-ple, gear widths up to 500 mm are measured in con-junction with a special probe arm made of ca
41、rbonfiber-reinforced plastic.In this case, the probe system must have the neces-sary load capacity and stability, and accept appropri-ate probe elements without affecting the measuredvalue recordings.Figure 09: Inspecting a large internal gear2.2 Control and computer systemIn addition to the mechani
42、cal components of an in-spection machine, the control and computer systemform the second essential component.The CNC-measuring control performs all the inspec-tion machine functions that are important for a meas-uring run. The schematic design of a control compu-ter unit can be seen in Figure 10. He
43、re the core ele-ments are a rapid 4-axes motion controller equippedwith microprocessors with a high clock frequency aswell as a higher-level control computer for multipleaxes interpolation and measured value recording. Inconjunction with special control software, up to 4measuring axes (X, Y, Z and C
44、) can be linked to-gether. The coupling can occur linearly or for anyspatial curves in accordance with predeterminednominal data.Further processing of measured values occurs in anevaluation computer, a standard commercial PCcomputer in a current design. The conception of themeasuring movement genera
45、tion and of the formationof measured values via the CNC control, on the onehand, and the presetting of the measuring run andprocessing of the measured values via PC computeron the other hand, guarantee high system reliability.To further increase availability, the control unit canalso be equipped wit
46、h a modem system. This allowsremote diagnosis/remote update of evaluation soft-ware and control software.The standard PC computer system also opens updiverse options for data storage and documentationof measuring results via printer systems.The interfaces between the inspection machine andthe operat
47、or are formed by the evaluation computer,including software, for checking the individual gear-related workpieces or gear cutting tools.Figure 10: CNC control concept3.0 Preparation and performance of a cylin-drical gear measurementThe operator guidance for the programs should bedesigned so that the
48、required measuring run can beprogrammed in plain text without special program-ming language. Graphically supported operator guid-ance offers further advantages. When programming arun, all necessary entries/specifications are made,such as: Record data for the measurement - such as place ofmeasurement
49、, name of the operator, order no. etc. Gear data of the workpiece - such as module,number of teeth, pressure angle, helix angle etc. Type of evaluation - such as DIN / AGMA / ISOevaluation, tip relief, root relief etc. Measuring run selection - such as profilemeasurement, lead measurement, gear pitch etc. Selection of the diagram magnifications etc.When programming is completed, the measuring runis stored in the computer under a workpiece identifi-cation number. In the case of repeat measurements,this run can be directly reactivated via a catalog ofstored runs. A program
