Steering Column Rotation Limiter With Retractable Stop Pin
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Solution Overview
Problem
Steer-by-wire steering systems require a rotation limiter to prevent excessive steering wheel rotation without a mechanical connection, but existing solutions are prone to rattling and wear due to tolerance issues.
Innovation Solution
A steering column with a torque-transmitting stop disk and a lifting mechanism that includes a stop pin and a wavy lifting link, allowing the stop pin to engage and disengage from recesses on the stop disk as the steering shaft rotates, preventing further rotation when the limit is reached, thus reducing wear and rattling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotation limiter with stop pin and recesses is provided in steer-by-wire steering systems, then the steering wheel rotation is limited to prevent excessive rotation, but the stop pin contacts the boundaries of recesses during operation causing rattling noises and wear
Solution Approach 1:
The stop pin is made displaceable in the axial direction through a lifting mechanism, allowing it to dynamically adjust its position. During normal operation, the stop pin is retracted axially to avoid contact with recess boundaries, eliminating rattling. When rotation limits are reached, the stop pin engages with the recesses to provide reliable mechanical stopping.
Solution Approach 2:
The lifting mechanism proactively displaces the stop pin axially to a retracted position before the steering shaft reaches its rotation limits. This preliminary action prevents the stop pin from contacting the recess boundaries during normal operation, thereby preventing rattling noises and wear before they can occur.
2Reliability
If the stop pin is constantly engaged with the recesses to ensure reliable rotation limitation, then the rotation limit is reliably enforced, but continuous contact causes wear and rattling noises
Solution Approach 1:
The stop pin transitions between two states: disengaged (retracted axially) during normal operation to minimize wear, and engaged (contacting recesses) only when rotation limits are reached. This dynamic state change ensures reliable limit enforcement while maximizing service life by minimizing contact duration.
Solution Approach 2:
The stop pin skips over the majority of the rotation range without contact, engaging with the recesses only at the critical moment when rotation limits are approached. This rushing through of the normal operation phase without contact minimizes wear while maintaining reliable limitation when needed.
Data Source
Figure 1~2
Figure 3~3a
Figure 4~5
AI summary
The aim of the invention is to provide a steering column for a motor vehicle, comprising a steering shaft (4), which is mounted in a steering column housing (6) in a rotatable manner about a longitudinal axis (L), and a rotation limiter (22), said steering column ensuring a reliable operation and having a low propensity for rattling. This is achieved in that the rotation limiter (22) has a stop disc (23) which is connected to the steering shaft (4) so as to transmit a torque; the stop disc (23) has at least one recess (24, 25) which extends in the circumferential direction; and the steering column (4) is coupled to a lifting mechanism (28, 29, 30), by means of which a stop pin (30) that is movable in the direction of the longitudinal axis (L) and is mounted in a fixed manner in the circumferential direction can be brought into engagement with the recess (24, 25) depending on the rotational angle of the steering shaft (4) such that the stop pin (30) abuts against a recess (24, 25) boundary (34, 35) lying in the circumferential direction when the permitted rotational angle of the steering shaft (4) is reached and a further rotation in the same rotational direction is prevented.