VDL Konings, Dutch manufacturer of medical devices, has chosen turntable bearings from Rodriguez for a C-arm x-ray machine. This arm has been developed for the use in oncology for diagnostic purposes. In order to prepare and perform treatments accordingly, the location of the tumour, the position and dose of the radiation must be determined prior to the procedure. For the high-precision positioning of the massive C-arm, the component for the bearing of this large system, is of great importance. Therefore, VDL Konings equipped this rotation position with ball bearing slewing rings from Rodriguez.
Rodriguez’s bearings are suitable for applications in which large tilting moments need to be supported or where large bearing diameters are required for design-related purposes. Thanks to their constructional design, they safely absorb radial, axial and tilting moment loads with one bearing point. Therefore, bearings with radial and axial bearing combinations can often be realized with only one bearing point, and expenditure and costs for the design of the connection construction and the installation of the bearings can often be significantly reduced. Different sizes and are available as a standard in two types, with double-sided sealed raceway system.
Narrower tolerances for axial and radial runout and the technical specifications provided by the customer required a customized design with a customized internal gear for VDL Konings’ application. Heat treatment prevents the rings from warping in the subsequent processing; warping would result in functional inaccuracies both in diagnostics and radiotherapy. The outer ring was slightly modified in order to meet the installation specifications, and the grease nipple was counter sunk. This prevents anything from hooking to the arm in its rotary movement. To ensure the arm rotates in the same plane, has no range of motion and has a homogeneous rotation, the bearing is clearance-free and designed according to the specific rotation moment specifications. In addition, the shape and tolerances of the gear teeth were modified to ensure smooth running, reliable motion accuracy and less wear.
Specially modified turntable bearings are also required in other fields of applications, for example as a hot version, which can be used in a temperature range of up to 150°C. For such high temperatures, the turntable bearing must be fitted with a special seal that has high thermal and chemical resistance. The guiding of the rolling elements is implemented in a steel cage, because synthetic material would reach its limits under such operating conditions. In the area of precision bearings, for example, large diameter slewing bearings with outside diameters of up to 1,400 millimetres, or even the increasingly popular rotary units with smaller diameters starting at 15 millimetres, can be manufactured. In linear technology, thanks to modern CNC machinery, it is possible to machine shafts and ball screw spindles with an outer diameter of up to 100 mm.