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1. A telescopic steering device comprising:
a steering column which is swingably displaceable around a tilt shaft disposed in a width direction; a front assembly which is disposed on a front side; and a rear assembly which is disposed on a rear side, wherein the front assembly is configured by disposing a front shaft on an inner diameter side of a cylindrical front column while a front end portion of the front column or a housing fixed to the front end portion of the front column supports a front end portion of the front shaft or a shaft member linked to the front end portion by a front rolling bearing to be only rotatable, wherein the rear assembly is configured by disposing a rear shaft on an inner diameter side of a cylindrical rear column while a rear end portion of the rear column supports a rear side portion of the rear shaft by a rear rolling bearing to be only rotatable, wherein among the front column and the rear column, one column is an outer column and the other column is an inner column, wherein one end side portion on an inner column side of the outer column in an axial direction is provided with an axial slit which is long in the axial direction of the outer column and a pair of sandwiched portions which interpose the axial slit from both sides in the width direction perpendicular to the axial direction, and a portion between both end edges of the axial slit of the outer column is configured as an expansion and contraction cylinder portion which can elastically expand and contract a diameter dimension, wherein one end side portion on an outer column side of the inner column in the axial direction is internally fitted to the expansion and contraction cylinder portion of the outer column, and in a state where the one end side portion is internally fitted, a state where a relative displacement between the inner column and the outer column in the axial direction is enabled and a state where the relative displacement is not enabled can be switched based on an elastic expansion and contraction of the diameter dimension of the expansion and contraction cylinder portion, wherein a spline shaft portion formed with a male spline portion on an outer circumferential surface is provided on one of a rear portion of the front shaft and a front portion of the rear shaft, a spline hole having a tip end which is opened and formed with a female spline portion on an inner circumferential surface is provided on the other of the rear portion of the front shaft and the front portion of the rear shaft, and the spline shaft portion and the spline hole are spline-engaged to be capable of transferring torque and to be slidable in the axial direction, and wherein if, among the front shaft and the rear shaft, a shaft which is disposed on an inner diameter side of the outer column is referred to as an outer column shaft, and a shaft which is disposed on an inner diameter side of the inner column is referred to as an inner column shaft,
an axial position of one end edge on an inner column side of the outer column shaft in the axial direction and an axial position of one end edge on an inner column side of the expansion and contraction cylinder portion of the outer column substantially match each other,an axial position of one end edge on an outer column side of the inner column shaft in the axial direction and an axial position of one end edge on an outer column side of the inner column in the axial direction substantially match each other,one end portion on the inner column side of the outer column is formed with a penetrating portion on an opposite portion of the axial slit in a radial direction to penetrate through the opposite portion in the radial direction, andthe penetrating portion is provided in a state of being overlapped with one end portion on the inner column side of the outer column shaft in the radial direction such that in a state before the one end side portion of the inner column is internally fitted to the expansion and contraction cylinder portion of the outer column, the one end portion on the inner column side of the outer column shaft is viewable from an outside of the outer column through the penetrating portion. |
