Vehicle Door Latch Driving Device Switch Timing
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Solution Overview
Problem
Conventional vehicle door latch units face challenges in durability and downsizing of switches used for controlling driving devices, particularly in the automatic closing and releasing mechanisms, due to varying designs and signal processing methods.
Innovation Solution
A driving device for a door latch unit incorporating a neutral switch and a gear detection switch, where the automatic closing function is initiated by a ratchet switch and ended by a neutral switch, with the gear detection switch switching from OFF to ON upon contact with a second cam surface during the automatic releasing function, allowing for a shorter ON time period and improved durability, and enabling a downsized gear interlocking cam body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple switches are used to detect latch and ratchet positions, then the control functionality is improved, but the durability of switches deteriorates and the cam body size increases
Solution Approach 1:
The patent combines multiple switch functions into a single integrated switch assembly. The cam body with multiple cam surfaces (first cam surface for neutral switch, second cam surface for gear detection switch) works with one switch unit to detect multiple states (neutral position, gear engagement, operation completion), eliminating the need for separate switches for each detection function and thereby improving durability while maintaining control functionality.
Solution Approach 2:
The single switch assembly serves multiple detection purposes by interacting with different cam surfaces on the cam body. The same switch unit detects both the neutral position (via first cam surface) and gear engagement status (via second cam surface), making the switch component universal and multi-functional, which reduces the total number of switches required and improves overall system reliability.
2Measurement precision
If multiple switches are used for detecting driving mechanism positions, then the detection accuracy is improved, but the cam body size increases
Solution Approach 1:
The patent uses a cam body with multiple cam surfaces arranged in different spatial dimensions rather than adding more separate switches. The first cam surface and second cam surface are positioned at different locations and orientations on the same cam body, allowing the single switch assembly to detect multiple positions through spatial differentiation, thereby maintaining detection accuracy without increasing overall cam body volume.
Solution Approach 2:
The patent integrates multiple detection functions within a single compact cam body structure. The first cam surface and second cam surface are nested or arranged on the same cam body, allowing multiple position detections to occur within a unified, space-efficient design rather than requiring separate cam components for each detection function.
Data Source
AI summary
A driving device includes: a neutral switch switches over from ON to OFF when an automatic closing function by a motor is operated and a first cam surface is released from a contact with the neutral switch; and a gear detection switch switches over from ON to OFF when an automatic closing function by the motor is operated and a second cam surface is released from a contact with the gear detection switch, wherein the operation of the automatic closing function by the motor is configured to be initiated by switch-over of a ratchet switch of the door latch unit from OFF to ON and ended by switch-over of the neutral switch from OFF to ON, and the gear detection switch is configured to switch over from OFF to ON by coming into contact with the second cam surface when the automatic releasing function by the motor is operated.