Ball bearing units are available as pillow blocks, flanged or take-up models with a broad spectrum of bearing housings from different manufacturers. Additionally countless combinations of housings and bearing inserts are possible. The comparability of the available products always means that the design engineer faces a difficult task in finding the optimal product for a particular automation solution, since there is no uniform standard. The greatest interchangeability is possible with respect to Asian dimensions. Special attention must be paid to specifications for hole spacing, mounting holes and mounting threads.
Small parts for a big effect
An alternative setting-solution is the self-expanding bullet point set screw. This set screw automatically expands when it is screwed in. As a result of the pressure of the bullet point on the shaft, the threads expand and interlock with the threads of the inner bearing ring; the screw cannot loosen and come out due to vibrations. In a vibration test, the bullet point set screw performed much better, with a life of 3,000 hours, than a rounded, non-self-expanding ball point set screw (2,500 hours) and a W point set screw (1,100 hours). The special design of the small components predestines this bearing unit for applications in which the shaft is subjected to vibrations, impact loads or high speeds, also from unbalanced masses. Under such harsh operating conditions, the potential for damage to the shaft and set screw can be reduced significantly as compared with conventional setting-solutions, thus increasing bearing performance.
Locking ring for high-speed shafts
The most recent innovations include the NU series, with extra-strong and evenly distributed holding power on the shaft. This is made possible by two concentric rings for 360° shaft contact. They feature a slotted inner ring on which a locking collar with a single cap screw is installed. Tightening the screw with a hex wrench causes the locking riball,ng and – due to the slot – the inner bearing ring to be pressed together. This provides evenly distributed holding power on the shaft, similar to an adapter sleeve. This type of mounting is pre-destined for high-speed applications, such as industrial fans or centrifuges, brush bearings and rollers. The solution also performs convincingly in many other environments, especially in the case of fast reversing applications, high accelerations in test stands or packaging technology.
A clean solution
For small-scale automation in the food industry or the chemical and pharmaceutical industries, as well as certain outdoor applications, miniature bearing units of the Clean Series are available in two types. The light load bearing units with an aluminum-zinc housing are available in steel and stainless steel as pillow block (UP-00) and flanged versions (UFL-00) with metric dimensions. The pre-greased bearing inserts are optionally sealed with a rubber-coated cover for shaft ends or through shafts to prevent the penetration of water. Filled with grease, this pro- vides a virtually impenetrable barrier to external ambient influences. This is especially advantageous during the cleaning of machines. The bearing seal provides reliable protection and prolongs the life of the bearings. To optimize the inner ring and set screw for the heavy-duty requirements of wash-down applications, the inserts are also available in stainless steel. For different mounting conditions, versions are available with a set screw or eccentric ring.
One material, many advantages
Ceramic ball bearings are suitable for achieving a long service life under critical environmental conditions, such as dry operation in vacuum applications or operation at high temperatures. These products are designed for heavy-duty performance. Hybrid bearings with steel bearing rings and ceramic balls are recommended for applications with high shaft speeds of up to 150,000 Dn. Standard models of the ceramic series are suitable for applications with temperatures of up to 500 °C, high requirements for corrosion resistance or use in a vacuum. They are also a good choice for applications in coating and insulating plants, since no lubrication is necessary. The open version of the Y7 series with norust steel rings and ceramic balls is also ideal for use in highly corrosive environments, such as chemical solutions or under water, and requires no lubricants or seals.