From shaking gear levers to vibrating displays: Customized absorber systems help to quiet components and, in turn, the noise in the driver's cab.
Absorbers are always specially tailored to solve individual problems. A perfectly designed absorber reduces vibrations, offers enhanced comfort and user-friendliness, and ensures compliance with legal requirements. They can be specially modified in line with specific requirements and installation space.
"Their operating principle is really quite simple," says Dr. Stefan Narberhaus, head of Industrial Development at ContiTech Vibration Control in Hanover. "Absorbers comprise a mass, usually made of steel, which vibrates in antiphase to the annoying vibrations. They also contain a spring, made of elastomer, which combines spring-type and cushioning characteristics."
The decision whether to use synthetic or natural rubber depends on the ambient temperature. But other factors such as resistance to media, the damping behavior of the compound, or other special requirements affect the decision for or against a particular material.
ContiTech offers a broad range of absorber designs, including conventional absorbers comprising a mass and spring. Hydraulic absorbers additionally feature an integrated fluid system to dampen the movement of the absorbing mass. By adjusting the fluid system, the absorber and dampening effects can be optimized individually and independently.
Thanks to their simple construction, a modular system, and integrated breakaway resistance, they can be used universally. ContiTech has also tested active absorber systems in standard production vehicles. In addition to the mass and spring, these active systems feature an electric actuator and work based on the principle of electronically regulated counter-vibrations. The concept can also be easily deployed in industrial vehicles.
Depending on the application, they can have different roles. As internal tube vibration absorbers, they are installed in the center of the drive shaft to reduce bending vibrations. Brake absorbers are screwed onto the brake caliper and reduce the noise generated there, while leaf spring absorbers help to reduce noise in vans. Clamped onto the leaf spring via body panels and backing plates, they help to reduce bending vibrations.
Custom absorber adjustment
ContiTech Vibration Control heads the development process for absorbers - from the customization phase to production maturity. The basis for optimizing comfort is a detailed vehicle survey. The ContiTech engineers start by measuring and evaluating the vibrations and acoustics, focusing on the interior.
Structure- and air-borne noise measurements using microphones and vibration measurements using triaxial acceleration sensors are conducted at the relevant transmission paths, including when the vehicle is being test-driven. The data provides information on the frequency levels to be absorbed, vibration displacement, the most effective attachment point, as well as the required size and direction of the absorber to be used.
Once all of the collected data has been evaluated, the specialists carry out fine-tuning with the help of an "absorber suitcase" which contains different masses that can be combined with each other according to a modular construction principle. This allows different absorber types to be created "on site". "Using the absorber suitcase enables us to assess the effectiveness of the absorber in action and to determine the optimum absorber design," indicates Narberhaus.
The absorber development process is rounded off by laboratory testing of materials and components. In a range of test procedures, the characteristics of the elastomer parts are defined, the components are assessed in dynamic tests, and their durability and behavior are analyzed under different temperatures. "This allows us to develop individual vibration solutions tailored to the relevant vehicle type," says Narberhaus.
Source: ContiTech AG