A comprehensive redesign by Printed Motor Works of its low profile, high power density wheel motor, developed for Ocado's warehouse robots, has given a large boost to its capabilities. Enhancements to its mechanical design have raised the axial load strength by up to 650% while being no heavier and all in the same space envelope and a maximum depth of less than 50mm.
The new XR15-05e in-wheel motor has also been made more robust, with stronger cable strain relief and an enhanced rotor to body seal. Deep groove ball bearings have been replaced with an angular contact bearing unit to better withstand offset axial loads.
Finite element analysis was used to verify the design improvements, and endurance limit analysis indicates a much-extended product life.
Also, the component count has been reduced by 30%, simplifying assembly for volume manufacture and reducing overall product cost. Electromagnetic active components have been upgraded, preventing a reduction in performance as battery voltage drops.
Encoder robustness and resolution have also been improved significantly. Gone is the optical encoder, which is replaced by an on-axis magnetic type. This offers greater tolerance to contamination and nearly double the resolution, with lower cost and no impact on the overall package.
The improvements were made possible by Printed Motor Works' years of experience and expertise in the serial production of the original drive motors for Ocado's warehouse robots, the workhorses of their Ocado Smart Platform (OSP).
Other possible applications for these upgraded in-wheel motors include industrial robots and AGVs, warehouse shuttle drives, personal mobility devices and directly driven turntables or mounts for radar, lidar and cameras.