1.1 Company introduction 1.2 Application selection of Ever-power high quickness gearboxes Ever-power has been active in mechanical engineering for 25 years. For almost 25 years, we’ve been manufacturing gears and mechanical gearboxes. Our goal is to keep providing state-of-the-art products to our customers through intensive core engineering and product advancement. We apply a maximally creative approach while addressing technical problems and specific requirements of our customers. Our goal is continuous development of products with a higher level of useful and quality parameters. We propose ideal solutions based on an intensive comprehension of each concrete app. We supply high-speed gear units especially for thermal power station, heat plants, oil and gas sector or sugar refineries. High quickness gearboxes are a key component for applications such: • Turbogenerator drives • Steam and gas turbine drives • Turbocompressor drives • Pump drives • Test benches Ever-power has custom in high velocity applications since 1977. The worldwide installation foot of the parallel shaft gearboxes totals over 800 units. The calculation and style software KISSsoft and a 3D CAD program SOLID-EDGE along with other instruments enable us to end up being maximally fast and flexible. Our team of design engineers cooperates with universities, study institutes and leading specialists from all over the globe. Ever-power uses state-of-the-artwork finite component method (FEM) software tools for determining and optimizing gear devices properties.
2.1 Item introduction High-velocity gearboxes designed and produced in Ever-power are designated mainly for power generation industry, compressor and pump applications. The manufacture is completed on the present day machine equipment and gearboxes are assembled using very own components or components supplied by European producers. All products undergo thorough testing on a dynamic test bench. The look and gear power calculation are performed according to API 613 5th Edition and AGMA 6011*. Item types: RS and RU gearbox type is made to withstand forces from meshing of double helical gears. They aren’t designed to withstand any external axial or radial load. R1T and R2T gearbox type is designed to withstand forces from meshing of single helical gears and external axial and radial load. The transmission of exterior axial load from HS shaft to LS shaft is usually through thrust collars. The gearbox is definitely self supporting and doesn’t need any reinforcement. It has a foot flange for installation to a base and jack bolts (levelling bolts) for easy set up. The gearbox does not require any particular maintenance. It is recommended to change the oil on regular basis or when changing the climate conditions – see the Operating Manual for details. Standard gearbox is altered for high speed operation in the temperature range between -50 / +50°C provided the oil preheating at low temperatures and oil cooling at high temperature ranges. If the gearbox be operated in hazardous area or under other special conditions, it has to be contractually agreed. The typical gearbox efficiency is normally higher than 98,5%. Total efficiency depends on plenty of elements, such as mesh losses, bearing losses, windage losses etc. Ever-power is competent to prepare customized solution to raise the gearbox effi ciency up to 99,5%. mesh losses gearing is certainly sized based on the transmitted power. Power is usually distributed by a customer. It isn’t possible to reduce mesh losses considerably, nevertheless Ever-power aims to optimize the losses to attain the best compromise together with gear life, strength and NVH behaviour. bearing losses these losses possess the biggest influence on the gearbox efficiency. It is necessary to create and size the bearing properly. windage losses windage losses have big impact on the gearbox efficiency if the gear circumferential velocity is high. It is possible to decrease these losses (up to approx 50%) utilizing the windage cover. additional losses gearbox efficiency can be affected by the essential oil pump losses (if used), oil injection reduction etc.
2.3 Key technical features Turbo Gear Units Catalogue © Ever-power Industry a.s. 2016, EN1604 Main Gearbox Components 2.3.1 Housing The housing contains 2 parts: the upper and the lower case. It is fabricated steel construction. The housing is optimized by CAE solutions to ensure for good stiffness, low noise emissions, superb cooling properties and minimum weight. In the low part there are ft for repairing the gearbox to the building blocks equipped by jack bolts and with provision for mounting of earthing screw (if the gearbox is set to the hazardous region). Addititionally there is located the oil input/result fl ange and provision for temperature detectors conduction to the junction package. In the upper component there is an inspection cover, looking at the correct lubrication of meshing gears, a breather and provision for vibration probes. Split encounter of the casing can be horizontal, parallel to shaft axis. Both parts are connected by bolts and fi xed by dowel pins. 2.3.2 Shafts and gears Both shafts are forged pieces. HS shaft is usually forged from one piece along with gearing. LS shaft and the gear are forged separately and the gear is high temperature assembled on the shaft. The backsplash ring is usually forged in one piece with the shaft or heat assembled. Both gears are surface to high precision. Teeth fl anks of HS pinion have special modifi cations to reduce the noise level and compensate the defl ection of shafts because of heavy load. A hunting tooth mixture is present for mating gears when a tooth on the pinion does not repeat connection with a tooth on the gear wheel until it has contacted the rest of the gear wheel the teeth. The shape of shafts ends depends on customer’s request (cylindrical, tapered, fl anged etc.). Both shafts are dynamical balanced in accordance to ISO 1940 or API 613. 2.3.3 Bearings Solely hydrodynamic bearings with more sliding faces are used because of high speeds and bearing load. These bearings are divided into bearings with: • fi xed geometry – there is no motion of sliding faces • tilting pads – sliding faces are moving
LS (low velocity) shaft is usually placed in plain journal bearings with cylindrical clearance (fi xed geometry). Among the bearings is usually radial (on the non-traveling end) and the other one (on the traveling end of the shaft) is mixed radialaxial bearing. The look and calculation of the bearings are performed according to the latest strategies. Bearings on HS (high speed) shaft are often tilting pad type because of high speed and pitchline velocity and both of them are radial bearings. Tilting pad bearings usually have four or five 5 pads and static load path goes either on one pad or between pads. Lubrication of these bearings can be reached by overflowing the area between pads or oil injection between pads by way of many nozzles which also protects pads against circumferential movement. When essential oil injection is used it is possible to decrease friction losses substantially. These bearings possess the best resistance against rotor instability because they do not generate any load causing instability
2.5 Gearbox Testing 2 Product description and key features 3 Gearbox selection 1 Introduction 2 Product explanation and key features 2 Item explanation and key features 2.5.1 Load testing of high-quickness gearboxes Testing laboratory for high-velocity gearboxes is a camera monitored modern place of work at Ever-power manufacturing plant in planetary gearbox Pilsen. The Powerful Check Bench is a tests facility built with a computer managed 1 MW motor with speed up to 3.600 rpm, managed load by a generator up to 710 kW of power, auxiliary gearboxes enabling testing of the main gearbox with increase to 35.000 rpm. The test bench have a lubrication center with adjustable oil fl ow from 10 to at least one 1.600 liters/ minute, controllable oil temperature and water cooling up to 800 kW of power. The lubrication is usually backed up with pneumatic pumps providing full volume of oil in the event of power outage. The tests process is immediately recorded while essential oil and bearing temperature, pressure, noise, absolute and relative vibrations are measured and used in a control room for assessment by a specific software.