Parking Lock Spring Contour for Stable Pawl Disengagement
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Solution Overview
Problem
Existing parking lock mechanisms for motor vehicles face challenges with high spring forces required to hold the locking pawl in the disengaged condition, especially when the vehicle is dynamically operated, due to preload loss caused by the fixed suspension of the pawl return spring during swiveling motions.
Innovation Solution
A parking lock design where the spring element is supported on both the locking pawl and a guide rod, with a geometrically configured support contour that increases the preload force during disengagement, compensating for the preload loss caused by swiveling, allowing for reduced actuation force and enhanced holding stability in the disengaged state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pawl return spring is fixedly suspended at the housing-affixed support and locking pawl, then the structure is simple, but the preload force is lost during swiveling motion causing high spring forces to be required for holding the disengaged condition
Solution Approach 1:
The guide rod is made axially displaceable instead of being fixedly mounted, allowing it to dynamically adjust its position during pawl swiveling. This dynamic adjustment maintains the spring element's preload force throughout the motion range, preventing the preload loss that occurs with fixed suspension arrangements.
Solution Approach 2:
The support contour of the guide rod is designed with a specific geometry that changes the spring element's effective length during guide rod displacement. This parameter change compensates for the swiveling-induced preload loss, maintaining adequate spring force without requiring excessive initial spring force.
2Device complexity
If the spring element is supported on a fixed guide rod, then the structure is simple, but the preload force decreases during disengagement due to swiveling motion
Solution Approach 1:
The guide rod transitions from a fixed mounting to an axially displaceable mounting, enabling it to move dynamically during operation. This displacement, guided by the support contour, actively maintains the spring element's preload force during the pawl's swiveling motion from engaged to disengaged state.
Solution Approach 2:
The support contour acts as an intermediary mechanism between the guide rod's axial displacement and the spring element's preload maintenance. Its specific geometry translates the guide rod's motion into a compensating effect that preserves the spring force throughout the disengagement process.
3Reliability
If the actuating device must overcome high spring forces to disengage the parking lock, then the holding stability is improved, but the actuation force required increases
Solution Approach 1:
The axially displaceable guide rod dynamically maintains optimal spring preload during operation, ensuring reliable holding stability without requiring excessively high spring forces. This dynamic adjustment allows the system to achieve adequate holding force while minimizing the actuation force needed for disengagement.
Solution Approach 2:
The support contour geometry enables real-time parameter adjustment of the spring element's effective length, optimizing the spring force throughout the operational range. This ensures sufficient holding stability in the disengaged state while minimizing the peak actuation force required to initiate and complete disengagement.
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 ensures that the parking lock maintains preload force during disengagement, preventing unintentional engagement and reducing the actuation force needed to disengage, thereby improving the stability and operational efficiency of the parking lock mechanism.
Implementation Method 1
The spring element preloads the locking pawl in the disengagement direction of the parking lock, so that the engagement of the parking lock takes place against the spring force of the spring element
Data Source
AI summary
A parking lock for a motor vehicle includes a pivotably mounted locking pawl (20), an interlocking element (60), and a guide rod (40). A spring element (80) preloads the locking pawl (20) in a disengagement direction of the parking lock. A first free end (83) of the spring element (80) is supported directly on a support section (24) of the locking pawl (20) and, during the swiveling of the locking pawl (20), rests against the support section (24) in a stationary manner. A second free end (85) of the spring element (80) is supported directly on a support contour (43) of the guide rod (40) and, during an axial movement of the guide rod (40), slides along the support contour (43). The geometry of the support contour (43) is configured such that the preload force of the spring element (80) does not decrease during the disengagement of the parking lock.