The Effect of Sensor Integration on the Load Carrying Capacity of Gears

Abstract

Classical machine elements have been around for centuries, even millennia. However, the current advancement in Structural Health Monitoring (SHM), together with Condition Monitoring (CM), requires that machine elements should be upgraded from a not-simple object to an intelligent object, able to provide information about its working conditions to its surroundings, especially its health. However, the integration of electronics in a mechanical component may lead to a reduction in its load capacity since the component may need to be modified in order to accommodate them. This paper describes a case study, where, differently from other cases present in the literature, sensor integration has been developed under the gear teeth of an actual case-hardened helical gear pair to be used within an actual gearbox. This article has two different purposes. On the one hand, it aims to investigate the effect that component-level SHM/CM has on the gear load carrying capacity. On the other hand, it also aims to be of inspiration to the reader who wants to undertake the challenges of designing a sensor-integrated gear.

A Review on Sensor‐Integrating Machine Elements

“…The authors have identified the following examples that can be categorized as sensor-integrating gears: i) Additively manufactured metal spur gear wheel with an integrated accelerometer; [115] ii) case-hardened metal helical gear wheel with hall sensor, accelerometer, temperature sensor, and microphone inside; [116] iii) plastic spur gear wheel with an eddy-current sensor in the teeth; [117] iv) metal spur gear wheel with resistance sensors on the side; [118] v) sensor-integrating metal spur gear with accelerometer on the side. [119,120]…”

“…There are solutions that are not comparable, because not every publication lists all the necessary properties and the parameters of the gears. Most information is given in the publication by Bonaiti et al [116] where the influence of the cavities and possible designs for integration are discussed in detail. The gear is casehardened.…”

“…As a consequence, the sensors can be placed at radial positions close to the shaft compared to interference-fit wheel connection. Solutions with a feather key [116] have a high load concentration at the feather key in the circular direction. So, for the circular positions with a certain distance to the feather key, integration is possible compared to interference fit.…”

“…The design of the connections is standardized according to for example, DIN 7190-1, [130] DIN 6892, [131] DIN 5480-1, [132] ISO 4156, [133] but research on sensor-integrated SHC is still limited to a few projects. Worth mentioning are the patents by Gandrud, [134] Bader, [135] Groche & Traub [136] as well as the works of Vogel et al, [137] Bonaiti et al, [116] Khan et al, [138] Golinelli et al, [139] Min et al, [140] Persson & Persson, [141] Seltmann et al [142] Groche as well as Bader describe a feather key (FK) to measure torques. In the first patent, Groche & Traub [136] a FK is described, which consists of two vertical crossbars connected with a transverse crossbar.…”

Manufacturing of soft capacitive strain sensor based on dielectric elastomer material for an elastic element of a jaw coupling

“…In recent years, attention has shifted from ordinary machine elements to sensor-integrated machine elements [4,5]. Examples of the first approaches of sensor-integrated machine element are a sensor-integrated gear, published by Bonaiti et al [6] and prototypes of smart couplings proposed by Schork et al [7]. Kirchner et al presented an extensive overview of various machine elements with integrated sensors from bolts, couplings and bearings to gears and gear shafts [8].…”