In Detail: Red Bull Pankl Steering Joint

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It’s common for teams to buy in certain parts from third party manufacturers, these can either be manufactured to the team’s design or from the manufacturers.  One example is the steering universal joint (UJ), a recent acquisition to my collection of F1 hardware is a Pankl part used by Red Bull Racing.  The steering joint allows the high mounted steering column angle down to the steering rack, whilst still allowing smooth rotational movement of the steering column. 

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This is an essentially simple part, teams may make their own UJ, but these parts also are available commercially.  The steering UJ sits part way along the steering column, as the steering column has to sit high inside the cockpit to be inside the mandatory footwell padding.  Thus the UJ is mounted near the pedals in the front of the monocoque.  Its function is to allow the rotational movement of the steering to be transferred through an angle.  Although the upper and lower sections of steering column are kept in largely the same orientation to each other once fitted to the car.  To do this inside the joint is typically a simple universal joint, two clevises formed at each end of the column, set at 90 degrees to each other and joined by bearings to a central block. Needless to say this is a safety critical part and must allow a significant load to pass through before any failure.

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This example is listed as part number ‘220 425 1001/0  11/40/0567-03’ which is not a RBR coding format, so it is a Pankl and not a Red Bull part, additionally there is Pankl branding on the part too.  It arrived as a complete assembly and has resisted my attempts to dismantle it, so it’s likely it’s not a serviceable part and is simply replaced when damaged or when it has completed its service life.

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Weighing in at just 245g and some 110mm in length.  Its formed in two halves, the UJ connects to the steering column with two large flanges each holes for four M6 fasteners.  This I find slightly odd for an F1 part, such large diameter flanges (50mm dia and 60mm Dia) are quite large and my recollection of F1 columns is the UJ mounts with a male\female joint concentric to the shaft axis, not large flanges.  So this part may not be a F1 race part, rather a R&D part (as it came with a collection of RBR R&D parts) used either for a prototype or rig test.

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Ignoring the two flanges, the shaft diameter both ends is 18mm with a 1mm wall thickness, for the red nitride side, the shaft narrows to 13mm dia as it enters the central UJ.  This end of the joint also has what looks like a mounting and shoulder for a 20mm ID bearing, this would support the upper column as it rotates.  Further underlining that this may not be a race part, is there is not bearing fitted, but in that position any bearing would have to be fitted before the UJ is assembled.  A drop bracket fitted under the dash bulkhead houses the corresponding bearing to fully support the column.

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In the centre the joint casing is split with the silver end forming a cup and the other side formed with a rubber boot.  Unable to remove the boot without damaging it the internals are sadly not visible, but the movement feels like a typical universal joint.  Having angled the joint to its maximum the most extreme angular movement it allows is 37-degrees.