Compact Power Resistor with Crimped Wire Adhesion
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Solution Overview
Problem
Conventional high power resistors, such as cement resistors and those designed for printed circuit boards, face challenges in in-vehicle environments due to large size, heat dissipation issues, and mechanical limitations, leading to installation difficulties and potential electrical and mechanical failures from vibration.
Innovation Solution
A low-profile power resistor with a resistor substrate on an insulating substrate, paired electrodes, and coated electric wires that pass through an insulating exterior material, using crimp terminals or concave parts for adhesion, allowing flexible mounting and reduced size while maintaining heat dissipation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large-sized cement resistor is used for high power discharging, then the power dissipation capability is improved, but the mounting space requirement increases and heat dissipation becomes problematic
Solution Approach 1:
The resistor body is divided into a ceramic substrate portion and a synthetic resin portion, with the resistive element formed on the ceramic substrate and the resin portion providing structural support and heat dissipation. This segmentation allows for compact dimensions while maintaining high power capability.
Solution Approach 2:
The resistor combines ceramic material for the substrate (providing high temperature resistance and structural stability) with synthetic resin for the body (providing insulation and heat dissipation). This composite structure enables high power dissipation in a compact form factor suitable for in-vehicle mounting.
2Manufacturing precision
If metal terminals with linear shape are used for PCB mounting, then the mounting precision is improved, but the adaptability to different mounting locations decreases
Solution Approach 1:
The lead wires are designed with flexibility to allow bending and routing to different mounting locations on the PCB. This dynamic characteristic enables the terminals to adapt to various circuit board layouts while maintaining reliable electrical connections, overcoming the limitation of rigid linear terminals.
3Ease of operation
If coated electric wires are extended out from insulating coating parts, then the ease of attachment to pipes is improved, but the mechanical strength decreases
Solution Approach 1:
The lead wires are integrated into the synthetic resin body during the molding process, combining the electrical connection function with the structural support function. This merging ensures that the lead wires are firmly anchored within the resin, preventing disconnection under vibration while still allowing external wiring flexibility.
Solution Approach 2:
The lead wires are positioned and secured within the synthetic resin body before the final curing process. This preliminary action ensures proper positioning and strong bonding, preventing disconnection under vibration while maintaining flexibility for external wiring routing.
4Reliability
If a reinforcement frame and insulating material are added to improve bonding strength, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The synthetic resin body serves multiple functions simultaneously: it provides structural support, electrical insulation, thermal management, and mechanical anchoring for the lead wires. This merging of functions eliminates the need for separate reinforcement frames and insulating materials, maintaining high reliability while keeping the structure simple.
Data Source
AI summary
A power resistor has paired harness electric wires that have one end parts connected to a resistor substrate, and other end parts pass through an exterior material made of insulating resin and extend outward. Crimp terminals, which are means for reinforcing affinity between the coating material of the harness electric wires and the insulating resin, i.e., the exterior material and for maintaining adhesion, are formed on predetermined portions of the harness electric wires. As a result, a short and small power resistor suitable for an in-vehicle environment is provided.