Vehicle Door Latch Detection Lever Cam Mechanism Waterproofing
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Solution Overview
Problem
Conventional vehicle door latch devices suffer from poor waterproofness due to the arrangement of detection levers and switches on the surface side, making them susceptible to dust and rainwater ingress, which affects their ability to reliably detect open and closed states.
Innovation Solution
The design includes a base with a latch and detection lever on one side and a detection switch on the reverse side, where the detection lever slides along a cam portion to rotate and toggle the switch based on the latch's position, keeping the switch protected from external elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the detection lever and detection switch are arranged on the surface side of the synthetic resin body, then the detection function is achieved, but waterproofness deteriorates due to dust and rainwater ingress
Solution Approach 1:
The detection switch is inverted from the conventional surface-side arrangement to the reverse-side arrangement. The detection lever penetrates through the synthetic resin body via an elongated hole, allowing the detection function to be achieved while the switch itself is protected on the reverse side from dust and rainwater ingress.
2Object-affected harmful factors
If the detection switch is moved to the reverse side, then waterproofness is improved, but the detection mechanism complexity increases
Solution Approach 1:
The detection lever acts as an intermediary element that penetrates through the synthetic resin body via an elongated hole. It transmits the mechanical motion from the latch on the surface side to the detection switch on the reverse side, enabling the switch to be protected while still performing detection function.
3Object-affected harmful factors
If the detection lever penetrates through the base via an elongated hole, then the switch is protected from external elements, but the manufacturing precision requirements increase
Solution Approach 1:
The detection mechanism is segmented into distinct functional parts: the latch on the surface side, the elongated hole in the synthetic resin body, the detection lever penetrating through the hole, and the detection switch on the reverse side. This segmentation allows each part to be manufactured and assembled separately while maintaining overall functionality.
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 configuration enhances waterproofness and ensures reliable detection of door states over time by isolating the detection components from dust and rainwater, while also allowing for secure locking and unlocking operations.
Implementation Method 1
a cam portion (73) on an outer periphery of the latch (7)... a detecting portion (302)... which penetrates through an elongated hole (42) provided in the base (4) into the accommodating portion (41) and slides along the cam portion (73)
Data Source
AI summary
A vehicle door latch device includes: a base fixed to a door; a latch pivotally supported on the base, and configured to be rotatable in association with opening and closing of the door, the latch having a cam portion on an outer periphery thereof; a detection lever pivotally supported on the base by a shaft, the detection lever having a detecting portion, which slides along the cam portion in association with rotation of the latch, and a cam surface, the detection lever being configured to be rotatable, by the detecting portion sliding along the cam portion, to a position corresponding to a rotational position of the latch; and a detection switch configured to detect open and closed states of the door by being turned ON and OFF by coming into contact with and separating from the cam surface in association with rotation of the detection lever.