Hydraulic cylinders
Many spherical bearings are being used in hydraulic cylinders, mostly for oscillating movements.
Situations which are hard to lubricate.
Lubricating facilities and external seals cost money, are malfunction and require periodical maintenance. They’re often on places which are difficult to access and cost more in the design for a construction. Also lubrication systems are often the cause of a detrimental environmental discomfort because of outgoing lubricant. If a Feroball® is being used, in many cases it is able to construct without these devices.
Outdoor application.
If cylinders are being used on ships (above or under water) it’s very important that the bearings are resistant against entering moisture. Even if there is a construction to protect the bearings from such circumstances, failure due to corrosion is not guarantied. Material choices like composite and stainless steel will guarantee a good moisture and corrosion resistance and a high level of operational reliability. Conventional spherical bearings often don not suffice to such demands. Bearings with a metal-metal-combination for their sliding surfaces have to be lubricated and are never corrosion resistant. Besides that bearings with a PTFE sliding surface are only little moisture and corrosion resistant. Therefor they are not very good wear resistant. This means that environmental influences have direct consequences on their lifetime performance. Feroball® bearings offer a good alternative in all perspectives.
Pivot points
Feroball® Spherical bearings are also often used in oscillating constructions, for example, in big harbour cranes, valves or drawbridges. In these cases, the bearings have to function under the next circumstances:
Hars circumstances.
Many of these constructions are being confronted to heavy weather conditions. They have to endure rain, wind and temperatures between -30 °C and +50 °C.
Minimum oscillating movement.
Because of a often minimum of angular movement and constant stress, the lubrication is slowly but surely being squeezed out of the contact areas. Feroball® bearings are provided with lubrication in their composite ball. Therefor it is not possible to squeeze the lubrication out of the contact area. This will improve their lifetime performance drastically.
Changing forces.
Hydraulic cylinders move back and forward, therefore the forces on the bearings change. These forces on the bearings are not only continually present, but also vary in nature. Bearings have to endure this. Because of the application of a composite ball and stainless steel rings, peak loads become absorbed in the bearing. Therefore peak loads can significantly decrease in a construction by using Feroball® spherical bearings.
Functional at very low dynamic load.
In several bridge concepts, over dimensioning led to big problems for pivot points. Because of the over-sized¬ construction the wrong surface pressure in the bearing is often reached, therefore it can not be pushed through the breakout moment. Because a hydraulic installation does have the power to press through, a vibrating movement starts in the construction. This vibrating movement is also known as stick-slip. The bearing moves very little and stands still again, the pressure in the hydraulics increases and the bearing moves and directly stands still again. Feroball® bearings are specially developed for these circumstances and are able to function at very low surface pressures. If this isn’t enough a special bedding-in-paste can be used. With this, the running in period of the bearing is being reduced, therefor the sliding resistance decreases even faster. Feroball® bearings offer a extremely good solution in such situations.
