The development of a single, flat mounted sliding system for armrests
Many adjustable car armrests have, up until now, been mounted on a pair of ball bearing linear slides to give movement through the X plane (open sections facing sideways), which gave them strength and stability under load. Initially Accuride designed solutions for front row occupant armrest slides, which in main consisted of a pair of “cambered” slides (angled together at approx 30 degrees).
Due to the increased influence of styling and marketing in the end product, the vertical package of armrests was gradually reduced to such an extent that the slide angle was virtually flat (approx 10 degrees).
In an effort to simplify the assembly process and cut assembly tolerances associated with aligning two slides, a single flat mounted slide was proposed. This slide was extremely basic in its construction (inner member, outer member, balls and ball retainer) and fell within Accuride’s standard product range. The issues with using this slide were vertical stability under load and movement effort control. The former was solved with the customer adding “outriggers” or “skids” to the armrest mouldings - which supported the armrest both laterally (side-to-side) and vertically (for end load deflection). The movement effort control was resolved with the customer inserting a silicon oil filled rotary damper and rack into the armrest mouldings, thus giving a controlled motion meeting the OEM’s specification.
After the success of the original project the automotive OEM approached Accuride to be a supplier for their follow-on project. This vehicle was to include a sliding armrest with a single flat mounted slide - but cost was critical. This requirement led Accuride to design a new slide profile.
To maintain lateral stability this new slide needed to be about the size of 2 x 35mm slides side by side (flat mounted). However this would not be favourable for any sort of end loading as the wider slide would deform too much along its centreline and fail at relatively low loads. However, in this orientation, standard slides suffer from a reduced strength when considering vertical cantilever forces, such as from an abuse load applied to the end of the bun, and to loads typically caused in crash situations.
To compensate, Accuride designed a new patented ‘Wide Slide’ profile in which the moving components are prevented from separation by an overlapping flange, significantly increasing its overload and crash performance.
