Extendable spline shaft, vehicle steering provided with extendable spline shaft, and method for producing extendable spline shaft

Abstract

Disclosed is an intermediate shaft (5) as an extendable spline shaft provided with an inner shaft (35) and a cylindrical outer shaft (36), said inner shaft being fitted in said cylindrical outer shaft so as to move in the axial direction (X1); an outer spline (38) provided on the outer periphery of the inner shaft (35); an inner spline (39) provided on the inner periphery of the outer shaft (36); a resin film (40) provided on the outer spline (38); and lubricant retention grooves (41) which are formed in the resin film (40) using a laser beam, and extend in the direction (D1) intersecting with the axial direction (X1).

Description

technical field [0001] The present invention relates to a spline telescopic shaft capable of extending and contracting in the axial direction, a vehicle steering device including the spline telescopic shaft, and a method for manufacturing the spline telescopic shaft. Background technique [0002] A spline telescopic shaft is known that can expand and contract in the axial direction (for example, refer to Patent Documents 1 to 4). The spline telescopic shafts according to the aforementioned Patent Documents 1 to 4 each include an inner shaft and a cylindrical outer shaft that are spline-fitted so as to be relatively movable in the axial direction. Furthermore, in the spline telescopic shafts according to Patent Documents 1 to 4, the outer periphery of the inner shaft is covered with resin. In addition, in the spline telescopic shafts according to Patent Documents 1 to 4, the inner shaft or the outer shaft is formed with lubricant holding grooves or recesses. [0003] More s...

AI Technical Summary

Problems solved by technology

However, it is difficult to form concave parts with high dimensional accuracy

[0016] Thus, in the processing methods of the lubricant holding grooves and the like disclosed in Patent Documents 1 to 4, it is difficult to form grooves of arbitrary shapes with high dimensional accuracy.

Therefore, in the splined telescopic shafts of Patent Documents 1 to 4, lubricant may not be reliably supplied to the sliding portions of the inner shaft and the outer shaft.

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