Hollow rack and manufacturing method, hollow rack end diameter reducing method and apparatus

Abstract

Method for reducing the diameter of an end portion on a cylindrical end side portion of a hollow bar, said hollow bar having on its other end side portion a rack formed with an end rack tool at both ends. In said bar, a depression is also provided between each end rack tooth and a corresponding adjoining portion of said end side portion having an inclined portion opposing the tooth side face of the corresponding end rack tooth and continuous to each of the both ends of the rack. First, the one end side portion is nipped by means of a jig including a jig member having a pair of convex portionswhich are to be fitted inside said depressions to position the bar, and a jig member which is to be clamped / opened with respect to the jig member; After that, a compression die having an inside diameter smaller than the diameter of the outer periphery is pressed onto the outer periphery of the end portion of the cylindrical end side portion projected from the jig up to a press-in depth M determined preliminarily based on the rack, so as to reduce the diameter of the end portion.

Description

technical field [0001] The present invention relates to a hollow rack used as a steering rack and the like for a moving body having wheels such as a steering device of an automobile, and also relates to a method and a device for reducing the diameter of the end of the rack. In addition, the present invention relates to a method of manufacturing a hollow rack used in teeth and pinions used in automotive power steering devices, etc., and a hollow rack, particularly a rack that can reinforce the end portion on which a threaded portion is formed. . [0002] This application claims priority based on Japanese Patent Application No. 2007-73625 filed on March 20, 2007, and Japanese Patent Application No. 2007-85678 filed on March 28, 2007, and in the specification These patent applications are incorporated by reference in their entirety. Background technique [0003] Conventionally, there are known methods and devices for forming teeth corresponding to the teeth of the upper die o...

AI Technical Summary

Problems solved by technology

However, although the hardness of the shaft portion 201 can be increased by heat treatment, the hardness of the end portion 203 cannot be increased for threading.

Therefore, if a strength test in which a load is input from the ball joint 210 arranged on the tire side ( Figure 29 middle arrow K), the strength of the end 203 or the inner peripheral thread is insufficient to cause the thread to loosen, and then the ball joint 210 will fall off as shown in Figure 30

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