Integral Key Lock Mechanism for Vehicle Gearbox Theft Resistance
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Solution Overview
Problem
Existing gearbox assemblies for electric power steering systems lack an integral key lock mechanism, which can be vulnerable to theft and do not effectively prevent unauthorized steering when locked.
Innovation Solution
A gearbox assembly with an integral key lock mechanism that includes an adapter with splines, a locking collar, and a torque transfer ring, which prevents over-torque damage and ensures the vehicle cannot be steered freely, while allowing for testing of the lock mechanism during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a key lock acts on the input shaft, then the steering assembly can be locked, but the lock mechanism is not integral to the gearbox and may be vulnerable to theft
Solution Approach 1:
The key lock mechanism is merged with the gearbox assembly by integrating the locking collar onto the output shaft within the gearbox housing. This combines the steering lock function with the existing gearbox structure, making it integral and harder to steal rather than a separate component on the input shaft.
2Reliability
If a locking collar is added to the gearbox, then theft resistance is improved, but the device complexity increases
Solution Approach 1:
The output shaft serves multiple functions: it carries the wheel gear for torque transmission and supports the locking collar for security. This multi-functional design adds theft protection without requiring entirely separate components, reducing overall complexity.
Solution Approach 2:
The locking collar is nested within the gearbox housing and integrated with the output shaft structure. This nesting approach allows the lock mechanism to be contained within the existing gearbox boundaries rather than adding external complexity.
3Ease of operation
If the key lock is fixed to the housing and movable, then it can engage and disengage the locking collar, but the structure becomes more complex
Solution Approach 1:
The key lock acts as an intermediary mechanism between the housing and the locking collar. It provides a simple engagement interface that can lock or unlock the steering by engaging or disengaging from the locking collar, maintaining operational simplicity.
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 integral key lock mechanism enhances theft resistance and prevents over-torque damage, ensuring the vehicle remains secure and functional.
Implementation Method 1
The adapter may have an inner part that is provided with a set of splines that extend radially inwards towards the center of the inner part that engage corresponding outwardly extending splines on the output shaft
Implementation Method 2
The splines may be an interference fit
Implementation Method 3
The worm gear may be rotationally fixed to the rotor and engages the wheel gear to transfer torque from the motor to the output shaft
Implementation Method 4
teeth on the perimeter of the wheel gear engages with the worm of the worm gear
Implementation Method 5
Within this hollow shaft a torsion bar may be provided which interconnects the input shaft and the output shaft. The function of the torsion bar is to allow a large relative angular displacement between the input shaft and the output shaft as the driver applies a torque to the handwheel
Implementation Method 6
The key lock may be fixed to the housing and is movable between an extended position in which a part of the key lock engages the locking collar and a retracted position in which the part is held clear of the locking collar
Data Source
AI summary
A gearbox assembly includes a housing, an output shaft, a wheel gear, an input shaft, a torsion bar, an electric motor, a worm gear and a key lock. The wheel gear may be fixed to the output shaft for engagement with a wheel gear. The torsion bar may connect the input shaft to the output shaft. The worm gear may be rotationally fixed to the rotor and engages the wheel gear to transfer torque from the motor to the output shaft. The key lock may include an adapter, an annular outer part, a web, and a locking collar. The key lock may be fixed to the housing and is movable between an extended position in which a part of the key lock engages the locking collar and a retracted position in which the part is held clear of the locking collar.