TORQUE TRANSMISSION COUPLING AND ELECTRIC POWER STEERING DEVICE

There is provided a torque transmission joint configured to transmit torque between end portions of a driving shaft and a driven shaft arranged in series in an axial direction, wherein an outer-diameter-side concave-convex portion is formed by alternately arranging concave portions and convex portions over an entire circumference either directly on an inner periphery of one shaft of the driving shaft and the driven shaft or on an inner periphery of a member fixed to the one shaft, an inner-diameter-side concave-convex portion is formed by alternately arranging concave portions and convex portions over an entire circumference either directly on an outer periphery of the other shaft or on an outer periphery of a member fixed to the other shaft, and the outer-diameter-side concave-convex portion and the inner-diameter-side concave-convex portion are engaged with a circumferential gap being interposed therebetween, and wherein an elastic member made of an elastic material is provided between the end portion of the driving shaft and the end portion of the driven shaft either directly or via another member such that torque can be transmitted between the driving shaft and the driven shaft.