The present invention relates to a gear assembly and, more particularly, to such a gear assembly which allows ease of adjustment of the relative position of its components. The invention is particularly applicable to gear assemblies for use in the steering of automotive vehicles.
A gear assembly of the rack and pinion type comprises a toothed nut located on a threaded input shaft so that rotation of the input shaft produces an axial displacement of the nut. The teeth of the nut engage with corresponding pinion teeth on an output shaft so that displacement of the rack nut produces a rotation of the output shaft. In such gear assemblies it is desirable to be able to adjust the relative positions of the rack and the pinion to ensure optimum engagement of the teeth.
The document U.S. Pat. No. 4,614,127 describes a rack and pinion gear assembly in which the output shaft is journaled in the housing by way of two eccentric bushings. Rotation of a bushing in the housing produces an angular displacement of the output shaft. Thus, by selected rotation of the bushings, the output shaft can be displaced to bring its teeth into optimum engagement with those of the rack. Once the optimum position of the bushings has been reached they are rotationally locked by punching part of the bushing into a corresponding notch in the housing. While this device ensures an optimum interengagement of the teeth, the locking of the bushings by punching is not completely satisfactory as the punching operation can cause undesirable displacement of the bushing.
The object of the present invention is to provide a gear assembly which allows optimum alignment of the gear components and in which the locking of the bushings is both simple and efficient.