Shift-by-Wire Parking Lock with One-Way Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional shift-by-wire control systems for automatic transmissions can be vulnerable to theft since the parking lock device can be actuated mechanically regardless of the electric power source, allowing unauthorized release of the lock state even when the vehicle is parked in the P-range.
Innovation Solution
A shift-by-wire control system that includes a manual device with a one-way transmission unit allowing manual operation force to lock the output shaft only when the electric motor is not powered, preventing the lock-release state from being manually activated without electricity, thus enhancing vehicle security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical component structure is used for the parking lock device to enable operation without electric power, then the system can bring the output shaft to the lock state even when electric power is not supplied, but the mechanical component can be maliciously operated to bring the lock state to the lock-release state, allowing vehicle theft
Solution Approach 1:
The manual operating force transmission path is segmented into two directional paths: one for locking (permitted) and one for lock-release (prohibited). The one-way transmission unit creates this segmentation by allowing force transmission only in the locking direction while blocking the lock-release direction, thus separating the functional capability from the security vulnerability.
Solution Approach 2:
Instead of allowing bidirectional manual operation of the parking lock device, the invention inverts the transmission capability by using a one-way transmission unit that permits operation in only one direction (locking direction). This inversion transforms the mechanical component from a potentially vulnerable bidirectional mechanism into a unidirectional security feature.
2Object-affected harmful factors
If a one-way transmission unit is introduced to prohibit manual lock-release operation, then vehicle theft is prevented, but the device complexity increases
Solution Approach 1:
The one-way transmission unit acts as an intermediary component between the manual operating force and the parking lock device. This intermediary selectively transmits force in the locking direction while blocking force in the lock-release direction, providing theft prevention without requiring complex control systems or multiple separate mechanisms.
Solution Approach 2:
The invention replaces complex electronic control systems or multiple mechanical components with a simple one-way transmission unit that achieves the same security function through passive mechanical design. This substitution reduces overall system complexity while maintaining the theft prevention capability.
Data Source
AI summary
A shift-by-wire control system includes a parking lock device that brings an output shaft of an automatic transmission device to a lock state when a range switching unit switches to the P-range. The parking lock device brings the output shaft to a lock-release state when the range switching unit switches to another shift range. An electric motor actuates the range switching unit and the parking lock device in accordance with an instruction of an operator. A manual device transmits manual operation force of the operator to the parking lock device when the electric motor stops. The manual device includes a one-way transmission unit permitting transmission of the manual operation force in a direction toward the lock state, and prohibiting transmission of the manual operation force in a direction toward the lock-release state.