Leaf Spring Parking Lock Amplifies Displacement
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Solution Overview
Problem
Existing parking lock devices in motor vehicle transmissions face issues with contact between the locking pawl and parking lock gear under severe vibrations, leading to potential destruction, which previous solutions have partially addressed but require further improvements to handle component tolerances and ease of assembly.
Innovation Solution
The parking lock device incorporates a leaf spring with a displacement ratio between the unlocking element and the locking element, where the leaf spring is fixed to a guide plate and has an elbow at its fixed end, allowing increased spring displacement and a form-locked engagement with the locking pawl, enabling compensation for manufacturing inaccuracies and ease of assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the unlocking element or push rod moves a larger distance backwards to unlock the locking pawl, then the locking element is secured in position, but the displacement ratio is reduced and the structure becomes more complex
Solution Approach 1:
The leaf spring is designed with a curved geometry including an elbow section that transforms the linear displacement of the unlocking element into a amplified displacement of the locking element. The curved path allows the locking element to travel a greater distance than the unlocking element, achieving the desired displacement ratio without increasing overall mechanism complexity
Solution Approach 2:
The leaf spring operates in a multi-dimensional space, utilizing both lateral deflection and rotational movement about its fixed end. This dimensional transformation converts the small linear movement of the unlocking element into a larger arc-shaped displacement of the locking element, effectively resolving the displacement ratio requirement
2Device complexity
If the leaf spring is fixed rigidly to the housing, then the structure is simplified, but manufacturing tolerances cannot be compensated
Solution Approach 1:
The leaf spring's elastic properties are utilized to absorb and compensate for manufacturing tolerances. The spring's flexibility allows it to adapt to variations in component dimensions while maintaining proper engagement between the locking element and locking pawl, eliminating the need for complex adjustment mechanisms
3Volume of moving object
If the locking element is positioned closer to the unlocking element, then the structure is compact, but the unlocking reliability decreases
Solution Approach 1:
The curved geometry of the leaf spring, particularly the elbow section, provides mechanical advantage that amplifies the unlocking force. This allows the locking element to be positioned closer to the unlocking element while maintaining sufficient unlocking reliability through the leverage provided by the curved spring path
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
This design enhances the parking lock device by allowing larger displacements to accommodate component tolerances and simplifies assembly, ensuring reliable operation and ease of retrofitting in existing transmissions, while maintaining the locking pawl in a secure form-locked position.
Implementation Method 1
a leaf spring (7), which is fixed to a guide plate (4), has the following sections: a fixed end (7a), an elbow (7b), a first leg section (7c), a second leg section (7d), a third leg section (7e) and a securing or locking element (7f)
Data Source
AI summary
A parking lock device for a motor vehicle transmission including a parking lock gear, a locking pawl, a locking element with an operating rod as well as a guide plate. The locking pawl engages with and blocks the parking lock gear when the parking lock is engaged and locked by the locking element, and when the parking lock is disengaged, the locking pawl disengages from the parking lock gear and can be locked in a form-locked manner. An unlocking element is fixed to the operating rod, and the unlocking element disengages the form lock before the parking lock is engaged. The locking element is arranged on a leaf spring which has a fixed end, a free end and a center arranged between the fixed and the free ends. The center can be moved outwardly by the unlocking element and the locking element is arranged on the free end.