Modular Electric Power Steering System

Abstract

A modular electric power steering system is disclosed. The system includes a tubular neck which guides a universal joint. The tubular neck has a certain bend angle. The system further includes a drive assembly that has an electric motor which is controlled by a control unit. The system additionally includes a gearbox assembly having a torque sensor and a gearbox. The system also includes a steering rod that has a shortenable tube. Further, the system includes a gearbox housing that houses the gearbox assembly. In addition, the system includes two tubular toothed rack housing halves that are shortenable. The gearbox housing is disposed between the two toothed rack housing halves. The system also includes two feet which are disposed at the respective outer end of the two toothed rack housing halves. The feet serve to fasten the power steering system to the vehicle. And the feet include a bushing for guiding the toothed rack.

Claims

1. A modular electric power steering system, comprising: a tubular neck configured to guide a universal joint, wherein the tubular neck is configured to define a certain bend angle; a drive assembly including an electric motor which is configured to be controlled by a control unit; a gearbox assembly including a torque sensor and a gearbox; a steering rod including a shortenable tube; a gearbox housing that houses the gearbox assembly; two tubular toothed rack housing halves that are shortenable, wherein the gearbox housing is disposed between the two tubular toothed rack housing halves; and two feet which are disposed at the respective outer end of the two tubular toothed rack housing halves, wherein the two feet are configured to fasten the power steering system to the vehicle, and wherein the two feet include a bushing for guiding the toothed rack.

2. The modular electric power steering system according to claim 1, wherein: the gearbox of the gearbox assembly is a helical gear mechanism; the steering rod includes a tube to which a toothing element is fastened; and the gearbox housing includes an upper gearbox housing in which the helical gear mechanism is accommodated and a lower gearbox housing in which the pinion is in engagement with the toothed rack.

3. The modular electric power steering system according to claim 1, wherein: the gearbox of the gearbox assembly includes a belt gear and a ball and nut gear; and the steering rod is a ball screw spindle.

4. A method for assembling a modular electric power steering system according to claim 1, comprising: selecting a gearbox assembly, a drive assembly, a gearbox housing and the feet from a standardized kit; adjusting a toothed rack to a desired length; adjusting a tubular neck to a desired angle; adjusting two tubular toothed rack housing halves to a desired length; arranging and aligning the individual modules with respect to one another, wherein the feet are rotated relative to the toothed rack housing halves such that a desired installation angle is set, and wherein the tubular neck is rotated along its longitudinal axis such that the desired bend angle of the universal joint is set; and fixedly assembling the individual modules by pressing, shrinking, and/or welding.

Description

[0015] FIG. 1 an exploded view of the modular steering system according to the invention

[0016] FIG. 2 a perspective view of the modular steering system according to the invention

[0017] The design example is explained with reference to an EPSp in which the servo unit is located on the steering pinion.

[0018] FIG. 1 shows an exploded view of the modular steering system according to the invention. The toothed rack 4 consists of a high-strength standard tube to which a toothing element is fastened. The gearbox housing here consists of a lower gearbox housing 7 and an upper gearbox housing 11. The pinion, which is in engagement with the toothed rack 4, is accommodated in the lower gearbox housing 7. In addition, a pressure piece for pressing the toothed rack against the pinion is provided in the lower gearbox housing 7 in the usual manner. The upper gearbox housing 11 houses the helical gear mechanism. A drive assembly 3, consisting of an electric motor and a control unit, is screwed to the upper gearbox housing 11. The upper gearbox housing 11 is furthermore closed with a cover 9.

[0019] The gearbox assembly 2 extends through the upper and the lower gearbox housing 7, 11 and consists of a torque sensor, a helical gear and the pinion.

[0020] The feet 8 consist of a tubular portion and have projections, each comprising a bore, which are used to fasten the steering system in the vehicle. They include a bushing for guiding the toothed rack 4 and are fastened to the outer ends of the toothed rack housing halves 5.

[0021] The tubular neck 1 includes the universal joint 10, which is configured as a constant velocity joint. The tubular neck 1 is already bent and is moreover rotated along its longitudinal axis during assembly such that the angle for connection to the intermediate shaft is precisely set.

[0022] FIG. 2 shows a perspective view of the modular steering system according to the invention in the assembled state. After shortening the elements to the required length (toothed rack 4, toothed rack housing halves 5), the elements are first arranged in relation to one another. The elements (feet 8, tubular neck 1) are rotated in such a way that the required crossing and installation angles are set. The components are then fixedly connected, e.g. by pressing or welding.