Problem: Transmission noise, transmission error (TE)

Objective: Reliable design of the gearbox, noise reduction

Image e-vehicle_analysis_time_and_spectral_analysis

Analyses in the time domain

Dynamic torsion angles in the gear components

Analysis of shaft torsion

Shock loads during load changes

Analysis of the stiffness in the drive

Analyses of acoustic behaviour in the spectral range

Identification of noise sources

Recognition of component resonances

Specialised software solution for the analysis of gearboxes

Causes and explanation for gearbox noises

Transmission error (TE) is one of the most important causes of transmission noise.
It is caused by several influences, for example

Elastic and static deformations under load
manufacturing deviations
dynamic effects during operation

The transmission error describes the deviation between the actual position of the output gear and the ideal position. This ideal position would be given if the drive wheel transmitted the rotary motion completely error-free.

In addition to noise in the gearbox, the transmission error can also cause other problems. These include

Increased wear
Lower efficiency in the drivetrain
Possible malfunctions

These effects play a particularly important role in applications such as wind turbine gearboxes or rolling element gearboxes.

Measurements on gearboxes

To determine the transmission error, the speeds and angular positions are measured using high-resolution encoders on the input and output shafts. The transmission error is calculated from the measurement data obtained. The evaluation takes place in the time and order domain.

At the same time, structure-borne sound signals are recorded with an accelerometer. The common time base of all measurement channels enables a correlation between transmission error and sound signals.

Gearbox whine and gearbox rattle - causes and explanation

Gear whine is mainly caused by the tooth profile and vibrations of the gears.
Typical gear mesh frequencies can be recognised in the frequency spectrum of the transmission error and in the structure-borne or airborne sound. These occur together with their harmonics and modulation sidebands. The latter are caused by rotational harmonics, for example due to concentricity errors.

Gearbox whine can occur at both high and low loads.

Gearbox rattle, on the other hand, only occurs at very low or no load, for example when an internal combustion engine is idling. This is caused by engine speed fluctuations resulting from uneven combustion. This causes the unloaded tooth flanks to lift briefly.

The existing tooth backlash is run through with every acceleration and deceleration of the drive shaft - often several times per revolution. This causes the teeth of the gears to strike against each other audibly.

Other possible causes of gear noises are unsuitable gear oil or air pockets in the oil.

#FAQs

Frequently Asked Questions

Have Question? We are here to help

What does the ROTEC solution for rotation analysis look like and what does RAS mean?

The ROTEC Rotational Analysis System (RAS) has been used for more than 30 years by users in the mechanical engineering, automotive, power generation and motorsport industries to comprehensively analyse rotating components.

With its unique measurement method using a 12.3 GHz counter card and a strictly angle-based approach to rotational speed detection and analysis, the RAS system offers users an unrivalled advantage.

ROTEC offers not only optical and magnetic speed sensors including signal conditioning adapters, but also the modular measuring system RASdelta as well as specialised and user-friendly software for measurement and analysis. This enables a complete solution from a single source. The ROTEC measurement technology products are perfectly harmonised and deliver meaningful results within a very short time after the uncomplicated setup of the measurement chain.

Thanks to the angle-based approach to speed measurement, problems such as sensor vibrations can be recognised after the first measurement and rectified immediately. This effectively prevents costly incorrect measurements.

Our team of experts at ROTEC ENGINEERING, consisting of long-standing users, will be happy to assist you with challenging tasks.

Are there options for customising the measuring systems and software?

The ROTEC RASdelta front end is a versatile modular measurement system that can be customised with 8 or 16 measurement cards to meet your specific measurement requirements.

Our RAS software offers you a comprehensive modular system for analysing rotating components and complex systems. It is an effective tool for mechanical engineers and requires no programming knowledge to perform measurements or analyses.

If you have specific metrological questions, our experienced ROTEC ENGINEERING consulting team will be happy to support you.

Does ROTEC offer other services in addition to the measuring systems, e.g. customised consulting or project support?

ROTEC not only offers speed sensors, signal conditioning, measurement systems (DAQ) and measurement and evaluation software, but also engineering and consulting services.

Our services include the design of measuring points in CAD, the mechanical processing of components, the application and calibration of sensors, the execution of measurement tasks and the evaluation of measurements according to our customers' requirements, including the presentation of the results. The ROTEC ENGINEERING team can also realise sub-projects as part of project support.

Is there training or technical support for commissioning and integrating the measuring systems?

In addition to our annual ROTEC Training Week, which is held in both German and English, we also offer customised training courses for users. These training courses are specially tailored to your individual application of the ROTEC measuring system and include practical demo measurements in your environment in addition to the theoretical basics and a detailed presentation of the software. This ensures that future users are optimally prepared for your specific application.

Furthermore, we are happy to support you in the commissioning of new measuring systems to enable you to familiarise yourself with the settings and possibilities of the RAS software as quickly as possible.

How is support ensured and are there self-help options?

In addition to our sales and support team in Munich, which serves the Central European market directly from here, ROTEC also cooperates with local partners in many global markets. These partners support local users with trained personnel for all matters relating to ROTEC measurement technology, first-level support and sales enquiries.

Our customers around the world appreciate the proximity of our sales and support teams, as this enables us to guarantee effective support even for short-term questions.

In addition to personal contact, ROTEC also offers an extensive knowledge database for self-help. Please register for our knowledge database to obtain detailed information on measuring and analysing torsional vibrations, transmission errors and valve systems, among other things.

Gearbox