Novel Elevator Overspeed Governor Design and Multibody Dynamic Analysis

Abstract

Overspeed governors are the crucial safety elements that have allowed the popularization of elevators for the last two centuries, being their main function to securely activate the safety breaks of the cab in an overspeed situation such as a failure in the machine or a rope break. The design of these elements has barely changed in the industry and still relays on a cam follower design that stops rotating when centrifugal forces reach a critical point. Such a design of multiple parts with relative motion induces wear, produces noise, and can even lead to availability reduction. In this paper, the design process and the multibody dynamic (MBD) analysis of a novel overspeed governor concept are presented, with the objective to reduce moving parts and improve the performance and robustness of the solution. A group of partitioners and experienced designers along with industrial partners have analyzed new creative designs, and a new governor typology is presented. Owing to the standard required sensitivity of the governor, a deep MBD analysis is performed to precisely define optimal design parameters. The proposed design has fewer moving parts and therefore is more resilient, reducing the possibilities of failure and the maintenance needs and therefore being a more cost-efficient solution. Optimization techniques have been implemented to fit design parameters and evaluate robustness. Additionally, the effect of manufacturing- or wear-induced clearances is analyzed for the traditional and the novel governor concepts, proving that the new concept is safer in the long term. The adopted design and analysis methodology can also be used for the improvement or definition of new overspeed governors.