Double Cardan Shaft And Cardan Joint
Double Cardan Shaft and cardan joint
Aconfiguration known as a double Cardan joint drive shaft partially over comesthe problem of jerky rotation. This configuration uses two U-joints joined byan intermediate shaft, with the second U-joint phased in relation to the first U-joint to cancel the changing angular velocity. In this configuration, theangular velocity of the driven shaft will match that of the driving shaft,provided that both the driving shaft and the driven shaft are at equal angleswith respect to the intermediate shaft (but not necessarily in the same plane)and that the two universal joints are 90 degrees out of phase. This assembly iscommonly employed in rear wheel drive vehicles, where it is known as a drive shaft or propeller (prop) shaft.
Evenwhen the driving and driven shafts are at equal angles with respect to theintermediate shaft, if these angles are greater than zero, oscillating momentsare applied to the three shafts as they rotate. These tend to bend them in adirection perpendicular to the common plane of the shafts. This applies forcesto the support bearings and can cause "launch shudder" in rear wheeldrive vehicles.[13] The intermediate shaft will also have a sinusoidal component to its angular velocity, which contributes to vibrationand stresses.
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