CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Entry of International Patent Application Serial Number PCT/EP2018/085647, filed Dec. 18, 2018, which claims priority to German Patent Application No. DE 10 2017 131 180.7, filed Dec. 22, 2017, the entire contents of both of which are incorporated herein by reference.

FIELD

The present disclosure generally relates to steering systems, including worm gears and worm gear systems of motor vehicle steering devices.

BACKGROUND

Gear systems which transmit an auxiliary torque from an electric motor to a steering shaft are inter aha required in the use of electro-mechanical power-assisted steering devices. The electric motor usually drives a worm which engages with a worm gear which is disposed in a rotationally fixed manner on the steering shaft or on a pinion.

The worm gear comprises an insert which is connectable in a rotationally fixed manner to the steering shaft or to the pinion, wherein said insert is enhanced with a plastics material. Said plastics material configures the so-called gear rim.

Worm gear systems are exposed to shock-type stress on account of which the forces generated by the maximum torque on the tooth flanks in normal operation lead to excessive stress. The tooth flanks are in particular highly sensitive to said shock-type stress.

A multiple-part gear wheel in which a connection part connects a hub to a gear rim is known from the first and unexamined publication DE 10 2014 104 284 A1. The connection part herein encloses the gear rim toothing in portions in the region of the end face.

This solution has proven disadvantageous in that a non-uniform distribution of force is created in the region of the engagement between the worm and the worm gear, on account of which more rapid abrasion of the worm gear system and thus more rapid wear is facilitated.

Thus a need exists for a worm gear for a worm gear system of a motor vehicle steering device which by way of ideally simple means enables an improved distribution of force in the engagement between the worm and the worm gear, thus enabling the transmission of higher torques.

