Steer-by-Wire Steering Locking Sleeve for Parking Stop Control
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Solution Overview
Problem
Steer-by-wire steering devices lack effective mechanical steering stops to prevent force-free rotation, especially in parking positions, and existing solutions are complex, expensive, or ineffective.
Innovation Solution
A steering device with a steering shaft, casing tube, and sleeve mechanism featuring a locking device that engages with recesses to mechanically block the shaft, utilizing an actuator to control the locking state, allowing for a space-saving and cost-effective solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical steering stop is used in conventional steering devices, then steering wheel rotation is limited, but this cannot be applied to steer-by-wire steering devices as mechanical and electronic components are not protected by a mechanical limit
Solution Approach 1:
The patent replaces conventional complex mechanical steering stops with a simplified locking device that uses a locking element engaging with locking surfaces on the steering shaft. This substitution maintains component protection while reducing structural complexity and improving compatibility with steer-by-wire systems.
Solution Approach 2:
The invention changes the steering stop mechanism from a fixed mechanical block to a controllable locking system where the locking element can engage or disengage based on operational requirements. This parameter change allows the system to provide mechanical limits only when needed, rather than continuously restricting motion.
2Reliability
If an electronic steering stop is used, then steering wheel rotation can be limited, but the electronic steering stop can be overcome with a corresponding application of force
Solution Approach 1:
The patent merges electronic control with mechanical locking by combining an actuator that controls the locking element with the mechanical steering shaft. This hybrid approach allows the electronic system to engage a physical locking mechanism that cannot be overcome by force alone, providing both rotation limitation and resistance to forced rotation.
Solution Approach 2:
The locking element acts as an intermediary between the electronic actuator and the steering shaft. It translates electronic control signals into mechanical locking action, providing a physical barrier that prevents forced rotation while maintaining electronic controllability.
3Reliability
If a series connection of multiple mechanical steering stops is used, then steering wheel rotation is limited, but the device becomes complex and expensive and force-free rotation cannot be prevented in parking position
Solution Approach 1:
The patent extracts the essential function of steering stops (rotation limitation) and implements it through a single locking device with locking surfaces positioned at different angular locations on the steering shaft. This eliminates the need for multiple separate mechanical stops while maintaining the ability to limit rotation at various positions and prevent force-free rotation in parking position.
4Reliability
If a locking device with multiple locking surfaces is used, then steering shaft rotation is reliably limited, but the device complexity increases
Solution Approach 1:
The locking device is designed with universal functionality where a single locking element can engage with multiple locking surfaces positioned at different angular locations on the steering shaft. This multi-functional design allows one component to perform the work of multiple separate stops, reducing overall device complexity while maintaining reliable rotation limitation.
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
Prevents force-free rotation of the steering shaft in parking positions through a simple, mechanical mechanism, eliminating the need for expensive gear units and ensuring reliable steering control.
Implementation Method 1
The steering shaft (7) has an external thread (17) which meshes with an internal thread (19) of the sleeve (11)
Implementation Method 2
the sleeve (11) is form-fitted into the casing tube (9) such that the sleeve (11) can be displaced in relation to the casing tube (9) in the axial direction (15) and is fixed in the circumferential direction
Implementation Method 3
The lateral surface (21) of the sleeve (11) has at least one recess (23), wherein the locking device (13) and the at least one recess (23) are arranged in relation to each other in such a way that the locking device (13) can engage into the at least one recess (23)
Implementation Method 4
the bolt (25) is pretensioned in a locked state and can be displaced into a released state by means of an actuator (39), in particular an electric motor, counter to the pretension, which in particular is generated by a spring
Data Source
AI summary
A steering device which is configured as a steer-by-wire steering device includes a steering shaft disposed for rotation in a circumferential direction, a casing tube at least partially encompassing the steering shaft where the steering shaft is fixed in relation to the casing tube in an axial direction of the steering shaft, a sleeve encompassing the steering shaft, and a locking device. The steering shaft has an external thread which meshes with an internal thread of the sleeve. The sleeve is form-fitted into the casing tube such that the sleeve is displaceable in relation to the casing tube in the axial direction and is fixed in the circumferential direction. A lateral surface of the sleeve has a recess. The locking device and the recess are disposed such that the locking device is engageable into the recess in an axial position of the sleeve.