Precise plain bearings in steering rod: even on bumpy track without clearance

One of the major challenges in the automotive industry is to stabilise components on uneven terrain in such a way that no BSR noises (BSR for buzz, squeak and rattle) occur. Noise development in cars is one of the most irritating issues for customers and costs original equipment manufacturers a lot of money through guarantee claims. Squeaking is a noise caused by friction between two mating surfaces, while a rattling noise is caused by impacts resulting from the short-term loss of contact between surfaces. The main causes of these noises are low tolerances, incompatible material pairs and structural deficiencies. 
The TATA Motors faced exactly these problems with the supporting structures for its steering rods, which initially consisted of a polyacetal ball bearing.
The manufacturer studied the problem thoroughly and compiled a list of requirements for a new solution. For example, the bearing should have no clearance towards the steering rod, but at the same time offer enough clearance for quick and easy assembly. The solution had to be able to be quickly integrated into the existing installation space without it having to be modified. The material of the bearing also had to generate very little friction and be vibration-dampening, wear-resistant, self-lubricating and environmentally friendly. Durability, lightness, dirt resistance and freedom from maintenance were also required. Finally, the bearing products also had to be able to operate at working temperatures of -40 to 120°C without any problems.

The high and partly contradictory requirements for the bearing solution demanded above all a well thought-out material. The TATA Motors finally found the solution in our iglidur bearing solutions, specifically the iglidur JVSM bearings.
These bearings are equipped with springs that enable radial pretension and thus tolerance-free driving. The iglidur J material used also offers several other advantages that were in demand in this application.
Originally intended for applications with clutch and brake pedals, it was used for the steering rod by attempting to insert it into the existing structure. This enabled immense improvements in BSR (buzz, squeak, rattle) performance, significantly reducing rattling, squeaking and humming noises. The car manufacturer verified the performance using its own test procedures and awarded the new solution a score. While a BSR score of 800 was achieved with the old solution, this was 8 with iglidur J bearings, whereby the lower the score, the better the performance.
The improvements had a very positive influence on the overall ride quality. In addition, high costs were saved due to the elimination of guarantee claims for the steering system. At the same time, it was possible to achieve this result with a simple design and minimised costs. Once the car manufacturer was satisfied with the test results, it implemented the solution in the production process.