Terminal Block Capacitor Mounting for Noise Filtering
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Solution Overview
Problem
Existing electronic apparatuses with metal cases and terminal blocks face issues such as stress on capacitors due to thermal expansion, increased manufacturing costs from printed boards and soldering, and reduced noise removal efficiency due to long noise current paths.
Innovation Solution
An electronic apparatus with a conductive case and a terminal block made of insulating material, featuring a capacitor and an elastic conductive member that forms a filter circuit to absorb stress and reduce noise current path length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitor is soldered onto a printed board inside the terminal block, then the capacitor can be electrically connected to the case wall, but stress is applied to the capacitor due to thermal expansion and contraction of the solder, causing cracks to form
Solution Approach 1:
The invention extracts the capacitor from the printed board assembly and directly mounts it to the terminal block body. This eliminates the solder connection between the capacitor and printed board, removing the source of thermal stress that causes cracks. The capacitor is now directly supported by the terminal block structure without intermediate solder joints.
Solution Approach 2:
The invention segments the electrical connection path by eliminating the printed board as an intermediate component. The capacitor connects directly to the terminal block and case wall through dedicated contact structures, separating the mechanical support function from the electrical connection function and avoiding stress concentration at solder joints.
2Reliability
If a printed board is disposed inside the terminal block to mount the capacitor, then the capacitor can be electrically connected, but the number of components increases and manufacturing cost increases
Solution Approach 1:
The invention merges the electrical connection function and mechanical support function into a single integrated structure. The terminal block body directly provides both structural support and electrical connection pathways to the capacitor, eliminating the need for a separate printed board and reducing component count.
Solution Approach 2:
The terminal block is designed to serve multiple functions: it provides mechanical support for the capacitor, establishes electrical connections, and guides the noise current path. This multi-functionality eliminates the need for dedicated printed boards and reduces overall device complexity.
3Reliability
If the capacitor is disposed far from the bolt to avoid stress from printed board warping, then capacitor reliability improves, but the noise current path becomes longer and parasitic inductance increases
Solution Approach 1:
The invention changes the spatial arrangement by utilizing the thickness direction of the terminal block. The capacitor is positioned adjacent to the case wall in the radial direction, and the noise current path is established through the thickness direction via contact structures, creating a short and direct path that minimizes parasitic inductance while keeping the capacitor close to the case wall.
4Strength
If the case wall and terminal block are fastened with a bolt, then the terminal block is securely attached, but the case wall and terminal block become bent or warped, applying stress to the capacitor and solder
Solution Approach 1:
The invention extracts the capacitor mounting structure from the warped region near the bolt. The capacitor is positioned and connected through contact structures that are located away from the bolt fastening point, eliminating the capacitor from the stress zone caused by warping while maintaining secure attachment of the terminal block.
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 effectively reduces stress on capacitors, lowers manufacturing costs by eliminating printed boards and soldering, and enhances noise removal efficiency by shortening the noise current path.
Implementation Method 1
an elastic member that is disposed inside the main body portion, the elastic member being composed of a conductive material, interposed at least one of between the capacitor and the external terminal, and between the capacitor and the case wall, and fixing the capacitor inside the main body portion by pressing the capacitor
Implementation Method 2
The capacitor and the elastic member configure a filter circuit that allows a noise current included in the external terminal to flow to the case wall
Data Source
AI summary
In an electronic apparatus, a case houses an electronic apparatus main body and is electrically conductive. A terminal block is attached to a case wall of the case. In the terminal block, a main body portion is composed of an insulating material. An external terminal is inserted into a through-hole formed in the case wall, and is connected to the electronic apparatus main body. A capacitor is disposed inside the main body portion. An elastic member is disposed inside the main body portion, is composed of a conductive material, is interposed at least one of between the capacitor and the external terminal, and between the capacitor and the case wall, and fixes the capacitor inside the main body portion by pressing the capacitor. The capacitor and the elastic member configure a filter circuit that allows a noise current included in the external terminal to flow to the case wall.