Hydraulic Park Lock Actuation With Pressure-Threshold Blocking
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Solution Overview
Problem
Existing park lock actuation systems for motor vehicles are complex and dependent on the state of the vehicle's electrical and hydraulic systems, making them inefficient for independent operation during charging or power failures.
Innovation Solution
A compact and simple park lock actuation system using a hydraulically actuated plunger and blocking element, coupled with spring-restoring forces, allows for independent operation by switching between locking and unlocking positions based on pressure values, ensuring the park lock remains active in power failures and can be kept unlocked without energy or pressure during transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a park lock actuation system is designed to be independent of the vehicle electrical and hydraulic systems, then reliability during power failures is improved, but device complexity increases
Solution Approach 1:
The system uses asymmetric pressure thresholds where the first pressure value for unlocking is lower than the second pressure value for locking. This asymmetric design allows the park lock to remain locked during power failures (reliability improvement) while using a simple pressure-dependent mechanism rather than complex control systems
Solution Approach 2:
The park lock actuation system uses self-service through pressure-dependent blocking elements that automatically switch between locked and unlocked states based on hydraulic pressure levels. The blocking elements mechanically respond to pressure changes without requiring external control systems, reducing device complexity while maintaining reliability
2Adaptability or versatility
If a blocking element is used to fix the actuating element in unlocking position, then transport function is improved, but device complexity increases
Solution Approach 1:
The blocking function is extracted as a separate, simple mechanical feature from the main actuation system. The blocking element operates independently through pressure-dependent engagement with the actuating element, providing transport capability without adding complex control mechanisms
Solution Approach 2:
The blocking element acts as an intermediary component that mediates between the hydraulic pressure system and the park lock mechanism. It translates pressure changes into mechanical blocking or unblocking actions, enabling transport function with minimal added complexity
3Ease of operation
If hydraulic actuation with pressure-dependent blocking is used, then ease of operation is improved, but loss of energy increases
Solution Approach 1:
The system uses periodic or intermittent hydraulic pressure application rather than continuous pressurization. Pressure is applied only when state changes are needed (unlocking or locking), and the pressure-dependent blocking elements maintain their positions without continuous energy input, reducing energy loss while keeping operation simple
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 system provides reliable and easy control over the park lock's operating states, ensuring it remains locked in driving mode and unlocked in transport mode, independent of power or hydraulic supply, with a compact design and reduced complexity.
Implementation Method 1
The actuating element can be displaced into its unlocking position by the restoring force of a (first) spring element
Implementation Method 2
The blocking element can be displaced into its blocking position by the restoring force of a (second) spring element
Implementation Method 3
The actuating element can be moved from its locking position into its unlocking position in a hydraulically actuated manner when a predetermined first pressure value is exceeded
Implementation Method 4
The blocking element can be moved from its unblocking position into its blocking position in a hydraulically actuated manner when a predetermined second pressure value is exceeded
Data Source
AI summary
A park lock actuation system for a motor vehicle includes an actuating element and a blocking element. The actuating element is translatable by hydraulic actuation from a locking position, in which a park lock coupled with the actuating element is active, to an unlocking position, in which the park lock is inactive, when a first hydraulic pressure value is exceeded. The blocking element is formed as a transverse slide and is movable, by hydraulic actuation, from an unblocking position, in which the actuating element is translatable between the locking position and the unlocking position, to a blocking position, in which the blocking element fixes the actuating element in the unlocking position in a form-fitting manner, when a second pressure value, higher than the first hydraulic pressure value, is exceeded.