Spherical Bearing
A spherical bearing (also known as spherical bush or elastomer bearing) is an elastic bearing made of rubber-metal that is used in the car body coupling of railway vehicles. Its main purpose is to accommodate movements between the car body and the coupler while simultaneously safely transmitting and damping forces.
Area of application
In the car body coupling of a railway vehicle, the spherical bearing plays a central role, as it fulfills several important functions simultaneously. First, it ensures safe force transmission and reliably transfers tensile, compressive, and shear forces from the coupling element to the car body and vice versa. In addition, thanks to its elastic design, the bearing compensates for relative movements of the car body. These include pitch, yaw, and roll movements caused, for example, by track irregularities, cornering, or other dynamic influences. Its elastomeric structure also ensures effective vibration and shock absorption, so that impacts during coupling, longitudinal vibrations during acceleration and braking, and loads caused by load changes are cushioned and do not reach the vehicle structure unfiltered. At the same time, the spherical bearing contributes to noise reduction by significantly reducing structure-borne noise, coupling noises, and metallic impacts, thereby enabling overall quieter and more comfortable operation of the rail vehicle.
Technical details
A spherical bearing consists of an inner metal body - usually in the form of an inner sleeve or inner core - an outer metal ring and a vulcanized elastomer with a spherical or hemispherical contour. This rubber body performs the actual bearing function. Thanks to its spherical geometry, the bearing can accommodate torsional and tilting movements as well as radial and axial movements across multiple degrees of freedom. Unlike conventional spherical bearings, the mobility is not generated by friction between metal surfaces, but exclusively by the elastic deformation of the rubber. As a result, the spherical bearing operates maintenance-free and quietly while also providing a self-spring effect.
Characteristics
The use of a spherical bearing in the car body coupling offers a number of significant advantages that positively impact both driving dynamics and the service life of vehicle components. The elastic mounting noticeably improves the smoothness of the entire vehicle’s ride as vibrations and shocks are effectively absorbed and dampened. At the same time, the bearing reduces peak loads that occur during coupling or during normal driving, thereby significantly reducing the stress on the connected components. The elastic design also ensures less wear and reliably protects the car body structure from dynamic loads. This significantly extends the service life of the coupling and all adjacent components. Furthermore, the spherical bearing helps mitigate material fatigue and reduces the risk of cracking. It thus serves as an essential element for mechanically decoupling the car body and the coupling, dynamically stabilizing the vehicle and simultaneously transmitting all forces safely and in a controlled manner.