The focus is on vibrations produced by actuators such as pumps, compressors and engines. There are different approaches to reduce noise and vibration: One method to reduce vibration and the resulting noise emission is damping. During material-based damping, kinetic vibration energy is converted into thermal energy. The principle of damping describes the reduction of an output quantity over time. Such conversion can be realised with the SITEC fasteners when using technical elastomers. Another method to reduce noise emission is the vibration isolation. In contrast to damping, there is no conversion of energy to reduce the amplitude, but a detuning of vibration. With this principle, an excitation is directly absorbed by a spring fastener and only transferred with a considerably reduced amplitude through a tuned spring rate. This type of reduction is primarily employed for strongly vibration-emitting applications. Intelligent joining Apart from the sophisticated geometry of the SITEC fasteners, the technical elastomers are the basis of intelligent joining solutions for vibration and noise decoupling. Currently, three different materials are available: EPDM peroxide, VMQ and thermoplastic elastomer EPDM-X+PP. The main characteristic on which to base the choice of material is the continuous operating temperature. In a further step, the individual materials can be chosen based on their Shore hardness. Depending on the requirements for the product, the appropriate material is selected. The general starting point for the four available product variants is the method to join the mounting part. Product clustering is realised as a plug-in variant, namely the SITEC Pin, or as a screw joint such as when using the SITEC Rivet, the SITEC Clip or the SITEC Spring. Decoupling blind rivet nut Let us have a closer look at the SITEC Rivet. As a fastening technology expert, Böllhoff has recognised the special role of plastics quite early. For decades, they have been producing precision plastic parts. Synergies with other joining technologies have resulted from the growing expert knowledge in the plastics technology so that new innovative products have been developed – such as the SITEC Rivet. This decoupling blind rivet nut allows the user to fasten a high-strength thread body to a thin-walled component with an additional vibration and noise decoupling effect. The SITEC Rivet consists of a metal sleeve which is usually a brass sleeve with a metric internal thread which is covered with elastomer or thermoplastic elastomer. Since the metal sleeve is only connected to the covering in the bottom part, a bulge forms on the rear of the component to be fastened when a screw is screwed in. The result is a reliable and reversible blind rivet joint with damping function. Among other industries, the SITEC Rivet is employed in the automotive sector, for example to fasten engine spoilers, filters or compressors. It is also a possible joining solution for the EV inverter in electric cars. Within the framework of a project, new developments according to application-specific requirements can be realised at any time. As a partner for 360° joining technology offering assembly and logistics solutions, Böllhoff takes the exact customer preferences and ideas into consideration. The best solution is sought for each application in a goal-oriented manner, always following the motto: „Passion for successful joining.“ SITEC as a possible joining solution for the EV inverter in electric cars SITEC Rivet – the decoupling blind rivet nut Image: © Böllhoff Graphic: © Böllhoff Böllhoff Group www.boellhoff.com/de-en Share 109
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