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Alternators used to have a solid pulley to connect it to the Front-End Accessory Drive (FEAD) system. Lately, new breakthrough designs have been developed for some applications, as the Overrunning Alternator Pulley (OAP) and the Overrunning Alternator Decoupler (OAD), with the aim to detach the alternator from the FEAD during high speed transients and to reduce the transmission of torsional vibrations from the internal combustion engine to the engine accessories, respectively. The downsizing of the internal combustion engine and its reduced idle speed to improve fuel economy and emissions led to belt slip or creep, increased NVH issues as chirpy noise or bearing reduced life due to the high vibration levels. Besides of that the increased demand for electric/electronics on-board systems led to the use of larger alternators, with bigger inertia, generating even higher vibration levels.

In response to several field failures of a specific model of starter drive - which is a component of starter motors used in Internal Combustion Engines (ICEs), - for application in heavy duty vehicles, a systematic Root Cause Analysis (RCA) was conducted in warranty returned parts. Controlled laboratory tests were not able to successfully replicate the failure mode. The failure caused the disassemble of the starter drive and it has become a difficult task to determine the root cause and propose solutions to fix the problem, therefore a deeper analysis of the warranty data was carried out by using both finite element analysis (FEA) and lumped parameter dynamic modeling and simulation. The FEA model was used to check potential weakness of the structural design that could point out the failure cause.

One-Way Clutch (OWC) systems have a concept based in a friction clutch with rollers. Such type of device is applied, for instance, in starter drives for starter motors and alternator overrunning pulleys. In the OWC configuration helical springs are positioned in such a way to guarantee the uniform contact of all rollers with the outer and inner races. This particular requirement is essential for the adequate performance of the system and becomes the weakest link of the current design. The objective of the present work is to investigate innovative design that could improve the system performance without increased cost. The development of a concept having a cage with integrated springs is described in this paper which is named ISC (Integrated Springs Cage). Furthermore, design improvements obtained by FEA simulation are shown. Finally, the experimental validation by durability tests demonstrates the feasibility of the proposed design.

In motorcycle engine starter the rotation of an electric motor (starter motor) is transmitted to the crankshaft to allow engine start up; as the engine starts, the rotation of the crankshaft should not be transmitted to the electric motor armature to avoid system failure due to the high rotational speed of the internal combustion engine. In order to obtain this function the starter system has a one-way clutch (OWC) assembled between the crankshaft and the driven gear that is rotated by the starter motor. The OWC assembly is held in position by the armature shaft of the electric starter motor. Considering the OWC dynamic performance, the study of the roller float condition can improve product durability by avoiding excessive contact between roller and race, the components responsible for the torque transmission.