Parking Lock Mechanism for Suppressing Parking Pawl Retraction
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Solution Overview
Problem
Existing vehicular parking devices face challenges in suppressing P-removal, where the parking pawl comes off the parking gear due to road surface slopes, requiring large design changes and increased device size to prevent retraction.
Innovation Solution
A vehicular parking device with a parking lock device featuring a first switching mechanism and a second switching mechanism that mechanically switch states to lock the parking head in place, preventing retraction without needing significant design changes or size increases, using a combination of locking members, engaging recesses, and elastic members to secure the parking pawl to the gear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stopper is disposed in the moving path of the parking head to prevent retraction, then P-removal is suppressed, but the device size increases and large design changes are required
Solution Approach 1:
The parking rod's moving path is segmented into two distinct regions: a first moving region where the parking head moves from the non-parking position to the parking position, and a second moving region where the parking head moves from the parking position to the retracted position. This segmentation allows different functional characteristics in different regions without requiring additional components, thereby suppressing P-removal while avoiding device complexity increases.
Solution Approach 2:
The support member is designed with dynamic geometric characteristics rather than static constraints. The first moving region has a smaller geometric gradient than the second moving region, creating variable resistance along the moving path. This dynamic geometry inherently prevents unwanted retraction without requiring mechanical stoppers or link mechanisms, thus maintaining device simplicity while ensuring reliability.
2Reliability
If a link mechanism is provided to advance and retract the stopper, then P-removal is suppressed, but the device size increases
Solution Approach 1:
The invention extracts the stopper function from the traditional mechanical stopper component and embeds it directly into the geometry of the support member. By forming the first and second moving regions with different geometric gradients within the existing support member structure, the patent eliminates the need for separate stopper components and their associated link mechanisms, thereby suppressing P-removal while maintaining compact device dimensions.
3Device complexity
If the parking head is allowed to retract freely, then the device structure is simple, but P-removal occurs on slopes
Solution Approach 1:
The support member is designed with non-uniform geometric characteristics along the moving path. The first moving region (from non-parking to parking position) has a smaller geometric gradient, while the second moving region (from parking to retracted position) has a larger geometric gradient. This local variation in geometric quality creates inherent resistance to retraction forces on slopes without requiring additional structural components, thus maintaining structural simplicity while ensuring parking stability.
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
Effectively suppresses P-removal by maintaining the parking pawl's engagement with the parking gear even on slopes, allowing for compact configuration without large design changes, ensuring stable parking operations with reduced force requirements.
Implementation Method 1
a first switching mechanism that is mechanically switched between a connecting state and a non-connecting state by suppression of movement of the parking head to the parking position side after the parking head reaches the parking position in accordance with the head moving member moving in an advancing direction
Data Source
AI summary
A parking lock device for positioning a parking head moved to a parking position in a parking position and holding the parking state includes a first switching mechanism and a second switching mechanism. The first switching mechanism is switched between a coupled state in which the parking head and the parking rod are coupled to each other and a non-coupled state in which the first switching mechanism is relatively movable. The second switching mechanism is switched between a locked state in which the parking head is positioned in the fixed case and an unlocked state in which the parking rod is retracted in the locked state to release the positioning of the parking head with respect to the fixed case.