Switch Device Snap Action Mechanism for Accurate Fault Detection
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Solution Overview
Problem
Existing switch devices for vehicle parking brakes can erroneously detect faults when the operation unit is held at an intermediate position, leading to incorrect fault diagnosis due to continuous contact or separation of contacts.
Innovation Solution
A switch device with a snap action mechanism that deforms a spring portion based on the operation amount, switching the contact state of a movable contact with fixed contacts, and a control unit that determines the operation state based on detection signals from these contacts, ensuring accurate fault detection and preventing erroneous readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the operation unit is held at an intermediate position during operation, then the contacts remain in continuous contact or separation state, but this leads to erroneous fault detection by the control unit
Solution Approach 1:
The snap action mechanism converts continuous operation unit movement into periodic, discrete contact state changes. The movable contact alternates between contacting the first fixed contact and the second fixed contact in distinct periods, ensuring that at any given moment the contact state is clearly defined rather than ambiguous, thus preventing erroneous fault detection while maintaining operational flexibility
2Reliability
If a snap action mechanism is introduced to switch contact states rapidly, then fault detection accuracy is improved, but device complexity increases
Solution Approach 1:
The snap action mechanism introduces dynamic elements (movable contact, spring portion) that automatically switch contact states based on operation unit position. This dynamic system ensures reliable contact state transitions without requiring complex control logic or multiple switches, as the mechanical snap action inherently provides the necessary state differentiation
Solution Approach 2:
The movable contact serves multiple functions: it contacts the first fixed contact to indicate one operation state, contacts the second fixed contact to indicate another operation state, and its movement itself serves as the switching mechanism. This multi-functionality reduces the need for additional components, offsetting the complexity added by the snap action mechanism
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
The snap action mechanism ensures reliable and rapid switching of contact states, avoiding erroneous fault detection even when the operation unit is held at intermediate positions, and reduces noise during state changes by maintaining contact with either the first or second fixed contact.
Implementation Method 1
a snap action mechanism that switches a contact state of the movable contact with the fixed contacts by deforming a spring portion in accordance with an operation amount of the operation unit
Data Source
AI summary
A switch device includes two fixed contacts and a movable contact of which position is changed when an operation unit is operated to selectively contact the fixed contacts. The switch device also includes a snap action mechanism that switches a contact state of the movable contact with the fixed contacts by deforming a spring portion in accordance with an operation amount of the operation unit. The switch device also includes a control unit that determines an operation state of the operation unit based on a detection signal received from the fixed contacts and the movable contact.