Door Latch Switch Layout for Secure Lock State Detection
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Solution Overview
Problem
The existing door latch devices for vehicles face issues with long-term functionality due to grease hardening and rust, and require multiple motor rotations to switch the lock mechanism between locked and unlocked states, which can generate unnecessary noise and require manual intervention in specific situations.
Innovation Solution
A door latch device equipped with a first and second position switch, configured to detect the operation of a cam mechanism, allowing for secure detection of the lock mechanism's state and enabling single motor operation to switch between locked and unlocked states without manual intervention, thus preventing noise and maintaining smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lock mechanism is switched by normal and reverse rotation of the cam wheel, then the locking and unlocking functions are achieved, but multiple motor operations are required increasing complexity
Solution Approach 1:
The cam wheel is designed with multiple functional surfaces that enable it to perform multiple functions: the first surface switches the lock mechanism between locked and unlocked states, the second surface releases the latch mechanism, and the third surface switches the lock mechanism again. This multi-functionality allows a single cam wheel rotation to accomplish multiple operations that would otherwise require separate motor actions, thereby reducing overall system complexity.
2Adaptability or versatility
If the lock mechanism is switched without releasing latch engagement, then the locking state can be changed independently, but the cam wheel configuration becomes more complex
Solution Approach 1:
The cam wheel is segmented into distinct functional surfaces (first, second, and third surfaces) with different profiles. The first and third surfaces are configured to switch the lock mechanism between locked and unlocked states independently of latch engagement status, while the second surface handles latch release. This segmentation allows independent lock state switching capability while organizing the complexity into manageable, functionally-separated surfaces.
Data Source
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AI summary
An operation of a detection target is more securely detected. A door latch device includes: a first switch 106 and a second switch 108 in which a first contact hole 200a connected to a normally open contact, a second contact hole 200b connected to a normally closed contact, and a common contact hole 200c connected to a common contact are arranged in the X-direction, the first switch 106 and the second switch 108 being disposed and stacked at positions shifted from each other in the X-direction; a common pin 130c inserted into the common contact hole 200c of the first switch 106 and a first contact hole 200a of the second switch 108 to be conducted; a first signal pin 130a inserted into the first contact hole 200a of the first switch 106 to be conducted; and a second signal pin 130b inserted into the common contact hole 200c of the second switch 108 to be conducted. The first switch 106 and the second switch 108 perform a switch operation at the same timing due to an operation of an operation detection target.