COMPLEX SPEED MEASUREMENT TASK WITH INDIVIDUALLY DEVELOPED SENSORS
Engineers are constantly faced with new challenges when it comes to speed measurements under difficult environmental conditions. One example is the measurement on the roller tappet or bearing to determine causes of wear and tear: Which sensor technology is suitable due to the tight space and extreme conditions such as high temperature and oily environment? And how can meaningful results be achieved? The following case study describes how the engineering team of Rotec Engineering, developed a customized miniature sensor for speed recording on the roller tappet and derives recommendations for action using suitable measurement and analysis software.
WHERE CAN TORSIONAL VIBRATIONS BECOME CRITICAL IN THE E‑POWERTRAIN?
The switch to electromobility is picking up speed. There are already 10.9 million e‑cars on the road worldwide (2020) and this number will rise to 34 million by 2030 (Ceresana forecast). In the development of e‑drive trains, the focus is on electric storage capacity, weight and size of the traction machine, durable powertrain components, ride comfort and thus quiet driving. Standard NVH analysis systems use airborne and structure-borne sound signals to study the generated noise, vibration, and their transmission paths, but usually ignore the mechanism of how these effects are generated. How can noise excitation be better studied, where can torsional vibrations become critical as well as dynamic loads, and what parameters should be collected?
IMPROVED APPROACHES TO THE MEASUREMENT AND ANALYSIS OF TORSIONAL VIBRATION ANALYSIS
A primary goal of NVH engineering is the identificationand control of noise and vibration sources. In recentyears the torsional vibration behaviour of engine and powertrain components has gained in significance. This paper discusses several aspects of measuring and analysing torsional vibration and related data. Several torsional vibration measurement techniques are presented, together with remarks on precautions against possible sources of error, and the order of accuracy to be expected of the test results. Two applications requiring multichannel measurement and analysis are outlined.
MEASUREMENT AND ANALYSIS OF TORSIONAL VIBRATIONS IN AUTOMOTIVE DEVELOPMENT
Torsional and rotational vibrations are mechanical vibrations caused by time-alternating torques which are superimposed on the otherwise steady running speed of a rotating shaft. In automotive engineering torsional vibration is primarily caused by the fluctuations in engine power output. This results in crankshaft angular velocity fluctuations which cause twisting and untwisting of the shaft. The effects of torsional vibration are amplified by torsional resonance which occurs when a shaft‘s natural frequency coincides with its torsional frequency. Excessive torsional vibrations can result in unwanted noise, powertrain component wear and, in severe cases, broken shafts. To identify such effects in advance and adopt measures to avoid them before ex-cessive damage has occurred, the development engineer requires dedicated, state-of-the-art measuring equipment incorporating application-specific software to simplify measurement setup and provide quick analysis.