Precise Steering Movements With Minimum Noise
Suspension strut bearings are part of the damping system and are subjected to massive forces. They must regularly withstand many times the weight of the vehicle. They are constantly exposed to dirt and – especially in the winter months – road salt. Despite all these harsh conditions, the bearing must perform its service safely in all situations and allow precise and smooth steering movements. If possible, for the entire life of the vehicle.
Rollax, a leader in the development and production of ball bearings for almost 50 years, meets these high challenges with a specially developed strut bearing. In addition to basic robustness, the lowest possible weight and the smallest possible component size are important. With the growing focus on e-mobility, the noise factor is becoming an increasingly important priority. In contrast to conventional combustion engines, electric motors have a significantly reduced operating noise level.
Teamwork Was the Key to Success
These demanding requirements could only be met in cooperation with the project partners involved. Close coordination and a constant exchange between the component manufacturer, Rollax GmbH, the injection moulder, Denk Kunststofftechnik from Gevelsberg and the material suppliers were necessary.
AKRO-PLASTIC supplies the plastic compounds for the strut bearing. These had to be very robust, insensitive to dirt and have a high dimensional stability. In combination with metal inserts and a sealing component, the plastic material became the lower part of the shock absorber bearing in a 3K process.
A further challenge was the worldwide shortage of polyamide 6.6, which dominated the plastics market right at the start of the project. Here, AKRO-PLASTIC was able to develop alternative products based on PA 6 together with Rollax GmbH. For the previously used PA 6.6 GF 25, a PA 6 GF 35 was used. The PA 6.6 GF 30 was replaced by PA 6 GF 50.
These two materials, AKROMID® B3 GF 35 1 schwarz (2486) and AKROMID® B3 GF 50 1 schwarz (20008), were successfully sampled and after intensive tests, released by the OEM for serial production. Due to the moderate increase of the glass fibre content, the necessary requirements of the components could be achieved, and the slightly higher water absorption of PA 6 was kept under control.
The processing parameters as well as the process windows only had to be slightly adjusted for this change. AKRO-PLASTIC was able to carry out the small adjustments quickly together with the project partners by means of application-technical consulting. AKRO-PLASTICs application engineering team consulted the project partners to quickly carry out the necessary adjustments.
The Project Partners
The ROLLAX GmbH & Co. KG was founded in 1972 by Joerg Schwarzbich as ROLLAX Kugellagerfabrik. Today, the company in Bad Salzuflen and in Nanjing, China, mainly produces customer-specific components for the automotive industry, among others. These are special bearings and motion systems for the areas of gears, chassis, steering and seats, but also for other applications where special bearings are required. ROLLAX is now managed by a foundation and has about 300 employees in Germany and about 50 in China.
Denk Kunststoff Technik GmbH
Denk Kunststoff Technik GmbH with its roughly 48 employees specializes in the manufacturing of technically demanding mass parts from thermoplastic material. We rely on more than 30 years of know-how in the application of injection moulding processes and in the conception and fabrication of the tooling required for the production process. It is this potential of experience, combined with state-of-the-art working equipment, that enables us to provide our customers with top-quality counselling – from the first product idea through to prototype manufacturing and batch fabrication and also to production phase-out – and comprehensive specialist service that goes far beyond the standard.