New generation of TAROL axlebox bearings: optimised design offers shorter mounting times and lower frictional torques
2018-12-06 | Sutton Coldfield
Safe and cost effective operation in rail applications begins with the mounting process. This is where Schaeffler’s optimised FAG TAROL tapered roller bearing units for automated mounting, together with a new fitting device, come into play. An optimised seal design for rail bearings reduces frictional power and operating costs.
SUTTON COLDFIELD, UK, December 06, 2018. The assembly of rail bogies is one area in which automation is making advances. To facilitate the process of mounting axlebox bearings, Schaeffler engineers have combined three individual components – axlebox bearing, labyrinth ring, and axle cover – to create a ready-to-fit unit. Two plastic retaining rings hold the components together on the inner diameter, and handling of individual components is no longer required. The new FAG TAROL tapered roller bearing units can therefore be pressed on more quickly during the mounting process.
The retaining rings are specially designed for every size and ensure that the labyrinth ring and the axle cover are seated firmly on the axlebox bearing without compromising the flow of force between the components. These retaining rings are also equipped with a rubber seal that seals the joining surfaces between the rings and prevents the ingress of moisture into the gap, which prevents corrosion damage to the axlebox shaft.
New ergonomic mounting device
The mounting device for rail bearings has been completely redesigned. The entire hydraulic system is now mounted on a height-adjustable scissor lift truck platform, and the fitter can set the platform to the required height using a foot pedal. The hydraulic cylinder has an articulated support and can be easily positioned to match the shaft end. The new mounting device is not only more ergonomic in its use but is also more cost-effective than its predecessor.
A version of the mounting device equipped with a digital force-travel measurement system and touchscreen enables the user to document the mounting and pressing-on of the bearing up to the shaft shoulder as part of the quality assurance process will also be available. The standard version of the new mounting device can be retrofitted to include this force-travel measurement system subject to customer request.
Cassette seal with optimised design envelope and friction characteristics
The axlebox bearing seals are responsible for a large proportion of the total friction and therefore the required drive power. As the friction on the seal continuously transfers heat to the axlebox bearing, the development of the new cassette seal is also focused on reducing friction, as well as ensuring a high level of protection against the ingress of contamination into the bearing. The design is structured in several stages: an outer dust shield prevents the ingress of coarse contaminant particles; a converging gap between the dust shield and the bearing ring also reduces the ingress of water and dust; the secondary shield gathers and ejects any residual contamination; the optimised design of the interference fit between the main seal lip and bearing ring allows friction to be significantly reduced. The new cassette seal therefore offers operators a way to save energy and operating costs, and also features optimised grease recirculation to the axlebox bearing, which improves its lubrication and operating life. Despite its high level of functional integration, the new seal design has allowed a reduction of up to 25% in the overall seal width to be achieved.
For more information, please contact Schaeffler UK’s Communications & Marketing Department on firstname.lastname@example.org or follow @SchaefflerUK on twitter.
Publisher: Schaeffler (UK) Ltd
Country: United Kingdom