An experimental study on the torsional stiffness and limit torque of a jaw coupling with consideration of spacer's hardness and installation methods

Abstract

The jaw coupling with a flexible spacer is frequently used in the torque transmission between shafts with misalignment for machinery. Its torsional stiffness and limit torque closely determine the operational capacity and the dynamic characteristics of the system because the coupling is usually the most flexible link in the driving chain. In this study, the optimal design of a jaw coupling with an elastomeric spacer was investigated using the Taguchi method by considering four design factors: the tightening method of the clamping bolts, the tightening torque of the clamping bolts, the hardness of the thermoplastic polyether ester elastomer spacer and the installation angle between the two end blocks of the coupling. All specimens were tested by using an in-house torsion tester to record the torque-angular deformation responses. The results showed good reliability and repeatability, with a coefficient of variance within 5%. Spacer's hardness was found to be the most significant factor regarding the torsional stiffness, while the magnitude of the clamping torque had the most critical role in the limit torque. The estimation formulae for the torsional stiffness and limit torque of the jaw coupling were obtained by using the statistical regression of the measured data, respectively. Both formulae predicted the performance of the optimal designs within 5% of error compared to the confirmation tests.

A Study of the Dynamic Stiffness of Flexible Couplings with a Rubber–Metal Element Type SEGME

“…The couplings [1] are used to connect shafts in different transmission systems for propellers [2], car engines, cranes, and many more. In some flexible coupling constructions, the presence of radial misalignment creates angular misalignment, which, in turn, affects the performance of the transmission [3].…”

“…The main dimensions of the semi-coupling with the flexible element are shown in Figure 1. The coupling consists of a metal flange with a hub (4), connected by means of bolts (5) to an outer ring (1), and a rubber flexible element ( 2) is vulcanized to it, which, in turn, is also vulcanized to the hub (3) for joining the shaft. The rubber element of the SEGME 25 coupling has a hardness of 53 • Shore A, and, for SEGME, of 63-73 • Shore A.…”

“…On a coupling-test stand [12], the general appearance of which is shown in Figure 2, measurements were carried out to experimentally determine the characteristic 𝑇𝑇 = 𝑇𝑇(𝜑𝜑) of the couplings. A bearing box ( 2) is mounted on a plate (1), in which the shaft (3) rotates on rolling bearings, on one end of which, by means of a sleeve coupling (4), one half of the coupling The coupling consists of a metal ring (1), a vulcanized rubber element (2) to it and to metal hub (3). The metal disc ( 4) is connected with a ring (1) with bolts (5).…”

“…On a coupling-test stand [12], the general appearance of which is shown in Figure 2, measurements were carried out to experimentally determine the characteristic 𝑇𝑇 = 𝑇𝑇(𝜑𝜑) of the couplings. A bearing box ( 2) is mounted on a plate (1), in which the shaft (3) rotates on rolling bearings, on one end of which, by means of a sleeve coupling ( 4), one half of the coupling A bearing box ( 2) is mounted on a plate (1), in which the shaft (3) rotates on rolling bearings, on one end of which, by means of a sleeve coupling ( 4), one half of the coupling under study ( 5) is mounted. On the other end of the shaft ( 3), a two-arm bridge ( 6) is fixed with the hangers (7) on which the weights ( 8) are placed.…”