ZOLLERN GmbH & Co. KG is a company with world wideoperations, employing over 3000 employees in the busi-ness fields of transmission technology (automation, gearboxes and winches), plain bearing technology, machinecomponents, foundry technology and steel profiles.
The ZOLLERN Group
ZOLLERN GmbH & Co. KG is a company with world wideoperations, employing over 3000 employees in the busi-ness fields of transmission technology (automation, gearboxes and winches), plain bearing technology, machinecomponents, foundry technology and steel profiles.
The Zollern Z type of horizontal bearings are designed acc.to different DIN and ISO specifications for a wide range ofheavy duty applications (electrical machines, fans andblowers, turbines and test rigs). The modular system appliesfor the different types of bearings (pedestal, end flange andcentre flange), i.e. the combination of different modules ofthis modular system is always possible. This has resultedin simple assembly and elimination of mistakes duringinstallation, commissioning and maintenance proceduresdue to the positioning of screws and pins.
Housing
The bearing housings are finned and manufactured fromnodular cast iron GGG 40 giving high strength and bestheat dissipation. The spherical seat in the housing ensureseasy alignment during assembly and the loads are steadyinduced to the lower part of the housing. Therefore thesebearings are designed for highest stress. Thread holes forthe fitting of thermosensors in the journal bush and oilsumpas well as for oil inlet and outlet pipes are provided on bothsides of the housings as a standard. Water cooling tubesand vibration probes can be easily fitted by small amendments of the housings.
Bearing shells
The shell is supplied in halves and spherically seated inthe housing ensuring easy alignment during assembly. Thematerial is low carbon steel lined with high tin based whitemetal. This construction allows easy assembly and long lifecycle. Bearing shells with plain cylindrical bore and looseoil ring are used in most cases, but other shapes of boreare possible. Optional water coolers are avilable and thebearing can be connected to an oil circulation. Where thespecific load on start-up is too high, or for slow speedapplications a hydrostatic jacking system can be incorpo-rated. Zollern will give recommendations for the oil supplypressure and the required flow rate. Bearing shells withoutthrust capability, or with plain white metal lined shoulders(small, temporary thrust loads) with oil grooves, or taperland faces (medium thrust loads) for one or both sense ofrotation can be selected depending on the level of thethrust load. The bearing shells are equipped with tiltingthrust pads for highest thrust loads
●0il supply
Fully self contained lubrication is achieved from a loose oil ring. Alternatively, where bearings are lubricated by an external oil circulation system, this loose oil ring can be used to permit emergency shutdown without damage if a system failure occurs. Z-bearings can be used for marine applications by using an oil ring guide to cater for vessel motions.
●Sealing
The seals are selected for the different operation conditions and for the requested protection level. The standard arran-gement is the floating labyrinth seal (IP 44) made of high heat resistant, fibre-reinforced synthetic material. Bearings for high oil throughput are equipped with adjustable rigid
seals (IP 44) made of aluminium alloy. Both types of seals can be equiped with bolt-on baffles (P 55) or dust flingers (IP 54) if the bearing is operating in a dusty or a wet envi- ronment or if rotating parts (clutches, couplings, fans etc.) are ftted close to the bearing. Special seals offering higher protection, or pressurized seals etc. can be supplied for special applications. Details upon request. An end cover is used while the end of the shaft is inside the bearing.
●Electrical insulation
To prevent stray curents conducted by the shaft Z-bearings can be supplied electrically insulated as an option. In this case the spherical seat of the housing is coated with a wear-resistant and temperature-resistant synthetic material.
●Selection of oil
It is recommended that any branded mineral oil (preferably inhibited against foaming, ageing and oxidation) is used as the lubricant. The viscosity for every application is selected by the Zollern bearing design computer program. The output resulting is provided with every quotation.
●Temperature control
Provisions for the ftting of thermosensors in the journal bush and oil sump are provided as standard. Which type of sensor is used depends on the type of reading (direct read-ing, centralized control system, recording instrument). It is possible to fit two different and independant thermosensors.
