Fastening elements for vibration and noise decoupling

Silence – a quality factor. NVH development (NVH = Noise, Vibration, Harshness) is becoming increasingly important. It is present in all industrial sectors from washing machines to vehicles, aircrafts and wind turbines. NVH stands for: The development is about avoiding vibration and is among the quality characteristics of a product which are most frequently directly observed. Excessive noise and vibration cause problems. They can affect the performance of a product negatively if it wears out earlier as a result, shows a less efficient performance or – in extreme cases – has a shorter product...

Contents Page SITEC® Variants - an overview 6 SITEC® Branches and applications 10 Standard design ■ with internal thread 14 ■ without internal thread 17 ■ Item codes and specifications 20 Special versions ■ with pre-installed screw 25

SITEC® Vibration technology The new product group of SITEC® vibration and noise decoupling fastening elements is our answer to today’s trend toward the NVH development. We only address vibrations produced by actuators such as pumps, compressors and engines. There are different approaches to reduce noise and vibration: 1) Damping One method to reduce vibration and the resulting noise emission is damping. During material-based damping, kinetic vibration energy/energy is converted into thermal energy. The principle of damping describes the reduction of an output quantity over time. Such conversion...

SITEC® Variants – an overview After this short excursion into vibration technology, we would like to introduce our new SITEC® product group to you. The following illustration provides a first impression of the product variants. Starting point are the possibilities of connection to the mounting part: VIBRATION AND NOISE DECOUPLING Plug-in connection SITEC® Rivet

Screw joint SITEC® Clip SITEC® Spring

SITEC® Materials Apart from the sophisticated geometry of the SITEC® fastening elements, the technical elastomers are the basis for intelligent joining solutions in vibration technology. There are three different manufacturing materials. The main characteristic on which to base the choice of material is the continuous operating temperature. In a further step, the Shore hardness of the individual materials can be chosen. Depending on the requirements for your product, we decide on the appropriate material. Since we closely cooperate with leading raw material manufacturers, new perspectives are...

Cross-linked elastomers/rubber Thermoplastic elastomer ■ Good temperature resistance between approx. -40 °C and +140 °C ■ Very good compression set ■ Good resistance to chemicals ■ Good resistance to mineral oils and greases ■ Very good temperature resistance between approx. -40 °C and +180 °C ■ Excellent ageing resistance ■ Low effect of temperature variations on the mechanical properties ■ Good mechanical properties between approx. -40 °C and +100 °C ■ Good resistance to chemicals ■ Good resistance to mineral oils and greases ++ very good, + good, 0 average, - bad

SITEC® Branches and applications Within the framework of a project, new developments according to your application-specific requirements can be realised at any time. We precisely incorporate your concepts and ideas to be able to offer you the best solution for your application. Automotive applications ■ Auxiliary heating system ■ Circulating water pump

■ Public health engineering

BOLLHOFF Page SITEC® Variants - an overview 6 SITEC® Branches and applications 10 Standard design ■ with internal thread 14 ■ without internal thread 17 ■ Item codes and specifications 20 Special versions ■ with pre-installed screw 25

SITEC® Rivet – standard design with internal thread As a fastening technology expert, Böllhoff has recognised the special role of plastics quite early. Already for decades, we have been producing precision plastic parts. It goes without saying that 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 RIVKLE® Elastic. This decoupling blind rivet nut allows to fasten a high-strength thread body to a thinwalled component with an additional vibration and noise decoupling...

Function The SITEC® Rivet consists of a metal sleeve which is usually a brass sleeve with a metric thread which is covered with elastomer or thermoplastic elastomer. Apart from the fastening function, the main benefit of the SITEC® Rivet is the vibration and noise decoupling characteristic. This is achieved by the elastomer covering. Since the metal sleeve (standard design: brass) 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....

SITEC® Rivet – standard design with internal thread As a standard, the SITEC® Rivet is available in two basic designs: n SITEC® Rivet with washer n SITEC® Rivet without washer The variant with washer is used as a damping joint for plastic, aluminium, composite or steel components with slotted holes. The advantage is that the force distribution is improved with the built-in washer and the component to be joined is not damaged. To join steel components (through hole as per DIN ISO 273), the SITEC® Rivet without washer can be used. There is then the additional advantage of a smaller head height...

SITEC® Rivet - standard design without internal thread The SITEC® Rivet without internal thread offers further joining options. Since a fastening thread (such as a weld nut) is required on the other component, larger wall thicknesses (or spacings) can be spanned and the components can be joined with a damping effect. As opposed to the variant with built-in internal thread, the rivet bulge is shaped between both components in the screw-in process. The SITEC® Rivet is simply i nserted into the existing bore on the component to be fastened and screwed into the weld nut (or similar) on the mounting...