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Final drives and rear axles
Published in M.J. Nunney, Light and Heavy Vehicle Technology, 2007
What is really required then is an in-built frictional means of automatically conferring resistance to rotation of the differential sun (or side) pinions relative to the differential case, according to the prevailing conditions of traction. This braking effect can be supplied by a pair of preloaded friction clutches of either the multiplate or the cone type. Taking for example the multiplate construction, the friction plates are held alternately on the outside diameter by lugs engaging with slots in the differential cage and on the inside diameter by splines connecting with the hubs of the sun pinions. Preloading of the friction clutches is achieved by one or more lugged plates being dished to act also as a Belleville spring. The frictional resistance to differential rotation of the sun pinions and hence the road wheels is derived from the following two sources: The spring loading of the friction clutches, which by imposing a fixed braking torque on the sun pinions relative to the differential cage guarantees that a certain amount of traction will always be available at one wheel, no matter how poor the grip may be at the other.The additional thrust loading on the friction clutches due to the separating forces created between the sun and planet pinions during torque transmission, these forces being of a similar nature to those described earlier for the crown wheel and pinion. Resistance to differential action of the sun pinions will therefore increase in proportion to the torque applied and inhibit wheel spin during acceleration.
Angular momentum transfer in direct numerical simulations of a laboratory model of a tropical cyclone
Published in Geophysical & Astrophysical Fluid Dynamics, 2022
Anna Evgrafova, Andrei Sukhanovskii
The key process that defines the differential rotation is the transfer of angular momentum. The tendency of fluid parcels to conserve angular momentum provides the formation of cyclonic flow in the lower layer because fluid with relatively high values of angular momentum moves from larger to smaller radii. The same process occurs in the upper layer when low angular momentum fluid moves to the periphery and produces anticyclonic flow. The system under consideration is not closed and there is an active exchange of angular momentum between the fluid and rotating at constant rate solid boundaries. In the area of cyclonic motion, where the fluid moves faster than the bottom, friction in the viscous boundary layer leads to the sink of angular momentum. At the periphery, the walls move faster than the anticyclonic flow and provide an injection of angular momentum into the fluid. A necessary condition for the existence of a stationary regime is the balance of angular momentum fluxes at the boundaries (Williams 1967, 1968). Experiments by Batalov et al. (2010) showed that in the case of heating at the periphery, the total angular momentum increases and in the present case (heating in the centre of the bottom) it decreases.