ContiTech Press Releases

Munich, April 2010Suspension systems for construction machines must be well tuned to each other • Legal limits set for vibrations in the workplace

Health is our most valuable asset – this old saying is also an important adage for manufacturers of construction machines. Because whoever provides the driver’s cab with optimum protection from vibrations also protects the user. And legislators are keeping an eye on those vibrations: the EU directive on vibration 2002/44/EC became part of German law already in March 2007. It specifies obligatory limits for vibrations in the workplace. Manufacturers are thus called upon to tune their suspension systems optimally to each another. The experts from ContiTech Vibration Control can provide them with valuable assistance in this regard with state-of-the-art measuring procedures.

Tracking down vibrations: a ContiTech employee uses mobile measuring equipment to analyze the vibration performance of a vehicle.

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In terms of vibration, the actual performance of industrial vehicles occasionally differs from what was calculated in the development phase. Instead of the desired vibration isolation, there is a chance of resonance effects occurring which could even intensify the vibrations. This isn't necessarily due to a design flaw. Sometimes changes in ambient conditions, such as different ground conditions to those used on the test bench, are enough to influence the vibration performance of the vehicle. This can result in higher mechanical loads being placed on components, and higher vibrational stress on the operator. The manufacturer now has no option but to get to the root of the causes of vibrational stress and reduce it.

Mobile measuring technology from ContiTech detects problem areas
ContiTech Vibration Control offers a special service to help with root cause analysis. The vibration reduction experts provide a mobile measuring service which can be used to determine vibration-relevant comfort improvements in prototypes and standard production cars. The manufacturer of vibration-control and noise-optimizing suspension components for plants, vehicle cabs, machines and engines has a mobile measuring system which can be used to analyze the vibration dynamics of plants and vehicles on-site. This procedure allows measurements to be made on vehicles which are in operation – be it an excavator or wheel loader, mobile crane or forklift. "We can investigate the vibration behavior of vehicles under real conditions, pinpoint the cause of undesired vibrations on-site and suggest measures for isolating and damping vibration," explains Jens Hoffman, branch manager for industrial vehicles at ContiTech Vibration Control. "The system is also just as good for analyzing new developments at an early stage in prototyping, thus allowing us to obtain valuable insights for further development."

Vibration tests under real conditions 
The system can take extensive measurements: “We can use these measurements to analyze all kinds of vehicle noise and vibration emissions. In this way we can determine the cause of air- and structure-borne noise and vibrations and give recommendations for neutralizing these problems," explains physics engineer Norbert Garbers of ContiTech Vibration Control.

For on-site measurement, the measurement data recording device, microphones and sensors are positioned in the vehicle and interlinked with cables. The measuring device and laptop are connected to each other via a WLAN. This means that the vehicle can be tested not only on a test bench but also on a test track.

Thanks to the stand-alone measuring system, it is possible to test a range of real-life situations – such as the idle mode, working mode or drive mode. To make sure the tests run smoothly on site, the specialists at ContiTech Vibration Control clarify beforehand what needs to be checked and how to conduct the test on-site. Measurements are usually carried out on one day and evaluated shortly afterwards by the ContiTech engineers. The customer is fully informed: At the end, he receives the analysis results along with improvement suggestions.