Leaf Spring Pressure Switch Design for Compact Size and Wear Reduction
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Solution Overview
Problem
Conventional pressure switches face challenges in reducing size while maintaining switching characteristics, as coil springs lead to increased size and potential wear when downsized, affecting detection accuracy and range.
Innovation Solution
A pressure switch utilizing a leaf spring as the biasing member, with an operation member that transmits movement to a switching member, avoiding direct force application on the transmission member, and featuring an adjustable biasing force to accommodate varying pressure ranges and detection accuracy through a diaphragm with a dome-shaped convex portion and a displacement restricting unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a coil spring is used as the biasing member, then the pressure switch can provide sufficient biasing force, but the overall size of the switch increases in the axis direction of the coil spring
Solution Approach 1:
The patent changes the physical form of the biasing member from a coil spring to a leaf spring. This parameter change allows the biasing force to be generated in a different spatial configuration, reducing the axial length requirement while maintaining the necessary force output through the leaf spring's bending mechanics
2Length of moving object
If the biasing member is simply downsized, then the overall size of the pressure switch is reduced, but a large force is locally applied to each member and contact portion, causing wear and changing switching characteristics
Solution Approach 1:
The leaf spring acts as an intermediary between the pressure-sensitive member and the transmission member. It distributes the biasing force along its length through elastic deformation, preventing concentrated stress at single contact points while still providing the necessary force to maintain reliable switching characteristics
Solution Approach 2:
Changing from a coil spring to a leaf spring fundamentally alters how the biasing force is distributed. The leaf spring's continuous elastic structure spreads the force application across multiple contact zones, reducing local stress concentration and preventing wear that would change switching characteristics
3Measurement precision
If the biasing force is increased to improve detection accuracy, then the switching characteristics improve, but the size of the pressure switch increases
Solution Approach 1:
The leaf spring's geometry parameters (length, width, thickness, material properties) can be adjusted to optimize the biasing force output. This allows detection accuracy to be improved through parameter optimization rather than simply increasing the overall size of the component
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 solution enables a compact pressure switch with improved detection accuracy and a wide pressure detection range, reducing wear and maintaining convex shape integrity, thus enhancing reliability and compatibility with high-pressure applications.
Implementation Method 1
the biasing member with the leaf spring... the leaf spring exerts the biasing force on the operation member
Implementation Method 2
a pressure-sensitive member such as a diaphragm or a bellows, which partitions a low-pressure chamber and a high-pressure chamber and is displaced by pressure fluctuation in the high-pressure chamber
Implementation Method 3
the operation member moves along with the displacement of the pressure-sensitive member, and this movement is transmitted to the switching member by the transmission member
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A pressure switch which can be downsized, and which can reduce a change in switching characteristics of the switch is provided. By using a leaf spring (7) as a biasing member, it is possible to reduce size of the pressure switch (1) as a whole, and particularly it is easy to reduce size in the motion direction of an operation member (5). Further, since the leaf spring (7) exerts an biasing force on the operation member (5) and the biasing force does not directly act on a transmission member (6), it is possible to suppress wear in a portion where a contacted portion (61c) of the transmission member (6) and a second shaft portion (53) of the operation member (5) contact each other even when the leaf spring (7) exerts a large biasing force on the operation member (5). Further, wear of a shaft member (63) and two shaft support holes (61e) and (61f) can be suppressed at the same time. As a result, it is possible to reduce the change in the switching characteristics of the micro switch (3).