First of its kind worldwide

SG Transmission has successfully developed and produced a combined permanent magnet and spring-applied brake based on the electromagnetic principle as a hybrid brake, which is considered the first of its kind in the world.

The hybrid solution was developed for a series of small, multi-axis surgical robots of the next generation, which are produced by a European innovation leader in robotics. Due to the critical requirements of the application and the operating environment, a solution was developed using both spring and permanent magnet technology to provide double redundancy in the event of a fault. The hybrid solution offers the advantages of both technologies and combines the high torque and zero backlash of a permanent magnet brake with the extended temperature range and advantages of a spring-applied brake.

Where fast and accurate stopping is required, spring-applied and permanent magnet brakes are known for their reliable, fail-safe performance. Unlike conventional electromagnetic brakes, they are designed so that the braking effect occurs when the power supply is interrupted (closed-circuit principle). Spring-applied brakes transmit torque through pressure generated by built-in springs on the brake disc, while the holding force in a permanent magnet brake is generated by multiple permanent magnets attracting the armature or brake disc.

Paul Short, development manager at SG Transmission, explained: "Although a hybrid solution with permanent magnet and spring-applied brake offers significant advantages, the complexity of the design and the mutual influence of the two interacting magnetic fields have so far prevented research into this concept. In addition to innovative development, the customer required a "plug and play" solution, which presented an additional challenge due to the small, compact design and limited axial length. To date, we have successfully delivered three versions of the brake in different sizes."

SG Transmission's development team worked closely with the customer throughout the project, using video conferencing and 3D data transfer to enable information to be shared and constantly aligned with requirements of the application - even in pandemic times.

Andy Collinson, Chief Executive Officer (CEO) of SG Transmission, said: "We were delighted to receive this unusual request. We are committed to our position in the industry as experts in bespoke electromagnetic solutions and this project has given us the opportunity to add another ground-breaking design to our product portfolio.