METHOD AND APPARATUS FOR MACHINING RACKS FOR STEERING GEAR

摘要

A machine for cutting the teeth of a rack for a variable ratio rack and pinion steering gear employing a helical pinion having a plurality of identical teeth engaged with a rack having some tooth gaps of varying form and angular disposition to the rack axis, the machine having a spindle carrying a tool with a single cutting tooth having cutting edges which lie on the surface of a single tooth of the helical pinion; the spindle is arranged for helical reciprocation in a housing between two predetermined limits about a mid position in which the tool is directed normally to the plane of the teeth of the rack, a rack holding fixture, the fixture or the housing being moveable with a relative translatory curvilinear motion during the cutting of a gap of the rack, the motion for any one gap being a part of the locus of the helical pinion when slid without rotation in the same gap of the rack.