Noise and concentricity tests of gears

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Noise and concentricity tests of gears

At fast single-flank and two-flank gear test or in rotational diagnosis and noise test of gears and drive trains with LiTW systems, the measurement can be carried out under the conditions that prevail when the test objects are in use.
Test speeds and short evaluation times allow 100% series control in production. When rolling (or toothing), the gearing creates typical, measurable behavior patterns that are detected by acoustic and / or geometric sensors and evaluated by test programs using computing methods. The results provide information about the composition of the error signal and thus enable the exact cause of the error to be identified (e.g. knockers, sum division errors, eccentricity, wobble errors, pressure angle errors). It is also possible to draw conclusions about previous work steps in which the geometry of the test object relates to incorrect or incorrectly set clamping devices.
  Double-Flank Gear Test Single-Flank Gear Test
  Geometrical test Noise test TAC-test (Torsional-Acceleration-Test) 
Characteristics
  • Center distance a ≠ const.
  • Testing speed ~25rpm
  • Compensation of the run-out of the clamping mandrel
  • Center distance a ≠ const.
  • Test speed ~300rpm
  • Clockwise and counter-clockwise rotation is tested
  • Center distance a = const.
  • Test speed ~600-6000rpm
  • Testing with torque on drive and driven side of the gear (6-23NM)
Test characteristics
  • Center distance a
  • Radial run-out Fr
  • Tooth to tooth composite deviation fi‘‘
  • Total composite deviation Fi‘‘
  • Two balls measurement MdK
  • Peak
  • Rms
  • Peak/Rms
  • Peak
  • Rms
  • Peak/Rms
Sensors
  • Linear sensor
  • Zero impulse
  • Vibration sensor
  • Rotational speed sensor
  • Torsion acceleration sensor
Testing system LiTW testing program Discom Rotas ZP Discom Rotas TAS
These new features have been added to assess the quality of gears and transmissions. The systems analyze the rolling noise and carry out a single-flank and double-flank rolling test / rotation fault diagnosis, in which the speed (up to nominal speed) and load torque can be variably adjusted. In addition, the backlash is determined and the concentricity error in the double flank contact is determined. Defective teeth are detected and marked with a special marking system (laser, color, inkjet markings) for reworking. Rework can be done directly on the test system and the part can then be automatically returned to the test. Other test methods - such as Diameter monitoring, center distance control, etc. - can be integrated. The test systems are either designed for interlinked fully automatic operation or for manual loading and unloading and it uses the same clamping devices as upstream processing machines. An extension can therefore be implemented quickly and inexpensively.

A number of well-known automobile manufacturers and suppliers around the world, major mechanical engineering companies and electrical groups are successfully and reliably using our systems and diagnostic systems. With the determined data of the different processes, statements are made about the quality. Interference sources or causes of errors (acoustic errors, design-related weak points, assembly, functional or manufacturing errors and damage) are identified and quality certificates are created. Statistical evaluations allow changes and trends in the manufacturing process to be recognized, controlled, sorted and corrected with reworking and smoothing machines. Tooth-precise errors can be recorded, marked and dealt with. By returning this information, industrial manufacturing processes with regard to product quality, manufacturing security and cost efficiency are optimized in a timely and goal-oriented manner. Time-consuming and expensive failures are avoided in good time with the help of the LiTW systems.

A gear test can be done in a variety of ways, e.g. by analyzing the noise behavior or mechanically, e.g. by means of a center distance measurement, determination of the rotational acceleration, or by a target / actual comparison of the theoretical and actual position of a gear pair) or by a combination of acoustic and mechanical test methods. The gear testing is based on single-flank and double-flank rolling.

Double-Flank-Gear-Test

The specimen and the master gear have a dynamic center distance to each other, in which the two components are in double-flank contact. The specimen is driven and the rolling wheel moves with a defined spring pressure on two-flank contact with the specimen. Due to geometrical errors or damage to the test object, the test slide moves with the unwinding wheel by the length ∆a.
Zweiflanken-Wälzprüfung
Zweiflanken-Wälzprüfung Draufsicht
This deflection is recorded for the geometry test with a linear displacement sensor. A vibration sensor is mounted on the testing slide for the noise test. In the double-flank test, single gears as well as whole entire shafts can be tested.
Evaluation of the gear test

Evaluation of the gear test

Evaluation of the noise test with error detection and determination for corrective action. With the help of integrated rework and smoothing stations, errors are eliminated full automatically.
Evaluation of the noise test with error detection and determination for corrective action. With the help of integrated rework and smoothing stations, errors are eliminated full automatically.

The Single-Flank-Rolling Test

Einflanken Wälzprüfung
The specimen and the master gear have a fixed center distance, in which the two components are in one-flank contact. The specimen is driven again and the rolling wheel is braked by another drive in order to apply the desired torque / speed ratio.

A torsional accelerometer (TAC sensor) is mounted on the drive of the specimen for the test. This records the differences in acceleration caused by division errors, damage, etc. and evaluates them using the appropriate software from Discom.
Evaluation of the TAC test - good part
Evaluation of the TAC test - good part
Evaluation of the TAC test - damaged gear with tooth-precised marking - part not ok
Evaluation of the TAC test - damaged gear with tooth-precised marking - part not ok
Eccentric gearing with contact pattern error – part not ok
Eccentric gearing with contact pattern error – part not ok

Optical surface inspection

Optische Oberflächenprüfung
With the optical surface inspection, the measurement data are recorded and output to a system controller via an interface. In addition, the sensor has a trigger input where automatic measurements can be started and assigned. This enables to detect chatter marks and roundness defects and assess the surface quality. The surface inspection works quickly, requires little maintenance, is robust and precise.
Optical surface inspection for checking surface quality and chatter marks
Optical surface inspection for checking surface quality and chatter marks
Optical surface inspection for checking roundness error
Optical surface inspection for checking roundness error

Marking and identification systems

Aufbringung eines Data-Matrix-Codes mit Hilfe eines Lasermarkiersystems
In order to increase the degree of automation and improve handling, we offer marking and labeling systems. These are used to mark and classify certain areas of the toothing on gear wheels and gear shafts. A total of 4 systems (laser, inkjet, needle embossing and color marking system) are offered. During the test, good and bad parts can be optically marked and the location of the greatest damage is marked tooth-precise. Impregnation of a tiny data matrix code is also possible. With the help of a camera check, all information (geometry, component properties, as well as component and batch numbers), test properties and unevenness of the parts can be read out again.