Steering Column Lock Rotor Asymmetry Prevents Key Overshoot
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Solution Overview
Problem
Existing steering column anti-theft locks are prone to unintentional key position changes due to 'knee kick' or sudden release, leading to engine shutdowns, as they lack effective mechanisms to prevent unauthorized rotation and maintain stable indexed positions during vehicle operation.
Innovation Solution
A lock design featuring a stator, rotor, cam, and elastic element, where the rotor's annular collar and opening configuration inhibit rotation in unintended directions, ensuring the key remains in the 'On' position until intentionally switched to 'Stop', preventing unintentional engine shutdowns by requiring user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical indexing system is used to hold the key in stable positions, then the key can be held in indexed positions (Stop, On, Start), but the key may come out unintentionally due to knee kick or brutal release causing engine shutdown
Solution Approach 1:
The opening in the stator head is preliminarily configured to block rotation in the direction of the Stop position from the On position. This preliminary blocking action prevents unintentional key position changes before they can occur, countering the harmful effect of knee kick or brutal release by anticipating and preventing the unwanted rotation
Solution Approach 2:
The user must preliminarily push the key in the direction of rotation before the opening can engage with the annular collar to enable rotation to the Stop position. This preliminary pushing action ensures intentional operation, preventing accidental engine shutdown by requiring deliberate user intervention before position change
2Ease of operation
If the key is brutally released from Start position to On position during engine start, then the key returns to On position by spring return, but the indexed position may be exceeded due to inertia causing unintentional engine shutdown
Solution Approach 1:
The opening is preliminarily shaped to block rotation beyond the On position by preventing engagement of the annular collar with the opening in the reverse rotation direction. This preliminary blocking counteracts the inertial overshoot caused by brutal release, ensuring the key cannot exceed the indexed position even during automatic spring return
Solution Approach 2:
The opening and annular collar are designed with asymmetric engagement characteristics: they engage easily in the Start to On direction but block rotation in the opposite direction. This asymmetry allows automatic spring return to On position while preventing overshoot beyond the indexed position, resolving the contradiction between ease of operation and position accuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces security issues by preventing unintentional key extraction and engine shutdowns, ensuring stable electrical functions during vehicle operation by requiring deliberate user action to change key positions.
Implementation Method 1
an elastic element arranged between the cam and the rotor for axially biasing said rotor by pushing
Data Source
AI summary
A lock for an antitheft device for a motor vehicle steering column is provided and includes a stator having a stator head with an opening, a rotor rotatably mounted about an axis with respect to the stator having an annular flange, a cam to rotate as one with the rotor, and an elastic element arranged between the cam and the rotor in order to exert a thrust load axially on the rotor. The opening of the stator is designed to engage with the annular flange to prevent the rotor from rotating in a predetermined rotation direction from a predetermined angular position and allows the rotor to rotate beyond the predetermined angular position by prior depression of the rotor.