September 2019

www.hpmag.co.uk HYDRAULICS & PNEUMATICS September 2019 39 so many different types of diesel-driven construction machines, each with their own performance requirements, selection of the appropriate flywheel coupling is a far from trivial exercise. Hydraulic driven equipment Where the diesel engine is to be coupled with hydraulic driven equipment, a prime consideration is how the overall equipment profile can be condensed, and how the OEMs can meet today’s increased volume demands at the lowest production costs. Thus while the flywheel coupling’s speed, torque and power specifications have to meet the performance requirements of the particular machine, just as important is the size of the product and its ease of installation – ensuring the OEMs can minimise the equipment profile and reap the benefits of simple installation, with repeatable quality, all helping to drive down manufacturing cost. Since most hydraulic applications are smooth running and direct mounted, either with a pump-to-motor adapter or with a pump plate, torsional vibrations and misalignment tend to be lesser issues than in other construction machinery applications. The flywheel couplings can be torsionally stiff, enabling the speed ranges to be extended above the standard operating speed range of the application. Products for such applications are typified by the Guardian brand FL Series flywheel couplings from Altra Industrial Motion – a two-piece flywheel coupling with decades of proven success in the field. An economical option, the FL Series flywheel is also highly compact: the entire coupling length is normally mounted inside the housing compartment. Installation is simplified since the coupling requires only a flat steel mounting plate to mount to the hydraulic pump. The design consists of a glass reinforced nylon flywheel flange, with a mating hub produced from sintered steel, suitable for use on both splined and straight shafts. Pumps, compressors and generators While hydraulically driven equipment typically present with smooth loads – free from vibration – and can be connected using torsionally stiff flywheel couplings, this is most definitely not the case for the likes of pumps, blowers, fans, compressors and generators. Being typically base or frame mounted, misalignment can be a concern, and torsional vibration cannot be ignored. Such applications are often best addressed by a one-piece, all steel flywheel coupling, such as the Guardian FBA Series. Here the flywheel coupling attaches to the engine for easy installation. It takes advantage of elastomeric grommets that provide a steady dampening effect to normal engine vibrations and help minimise any side loading to the pump shaft. The coupling is suited to a wide range of diesel engine applications, including aerial lifts, skid steer loaders, excavators and low mass compressors. Another option for absorbing vibrations and reactive forces where misalignment in particular is a concern is the Stromag brand’s Periflex CS Cardan Shaft Coupling. The ring element can be screwed directly to the flywheel of the engine. The cardan shaft is flanged to the coupling’s B side. Deflection angles of up to 5° are generally permitted, and even greater angles can be accommodated with special versions of the coupling. Torsionally soft couplings are also the best choice for applications involving high mass moments of inertia, and in many cases their design can serve to offer protection to both the engine and the driven equipment in the event of an overload. Guardian Guard-Flex flywheel couplings, for example, have an in-shear design that acts as a mechanical fuse, severing the driver from the driven load when an overload is present. Designed to fail through the rubber and shear, the coupling prevents the equipment from being damaged. Altra Industrial Motion has the ability to satisfy all of the performance and functional requirements of flywheel couplings in construction machinery and has a broad and diverse product offering to suit the needs of individual applications. With an appropriate flywheel coupling to address all potential issues, Altra Industrial Motion can offer products from the Guardian and Stromag brands that absorb vibrations and reactive forces, cope with torsional impact, handle high axial and radial loads, and tolerate misalignment. Further, they meet the increasingly important needs of construction machinery OEMs for smaller parts that are rugged, reliable, compact and easy to install. www.altramotion.com Altra Industrial Motion has the ability to satisfy all of the performance and functional requirements of flywheel couplings in construction machinery and has a broad and diverse product offering to suit the needs of individual applications.