Electromagnetic Relay Dual Circuit Shock Resistance
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Solution Overview
Problem
Conventional electromagnetic relays are insufficient for controlling three-phase brushless motors in electric power steering systems due to lack of miniaturization, high current-carrying and interrupting capabilities, and space efficiency, requiring multiple relays and increased component density.
Innovation Solution
A compact electromagnetic relay design with two circuits, each having an ordinarily-open contact, utilizing an electro-magnet block, card block with insulating material, and base block to support movable and fixed contacts, allowing synchronized operation and improved resistance to shock and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single electromagnetic relay is designed to control two circuits with high current-carrying capability (100A) and interrupting capability (100A at 14V), then the relay can control one three-phase brushless motor for electric power steering, but the relay size and component density increase
Solution Approach 1:
The patent combines two circuit control functions into a single electromagnetic relay body. The relay includes a first circuit with normally-open contacts and a second circuit with normally-closed contacts, both controlled by a common coil assembly. This merging of multiple circuit control functions into one relay unit achieves high adaptability for controlling three-phase brushless motors while managing the size through integrated design.
Solution Approach 2:
The electromagnetic relay is designed with multi-functionality to control both normally-open and normally-closed circuits simultaneously. The relay can control two circuits (first and second circuits) with different contact configurations using a single coil assembly, making it universally applicable for various switching requirements in electric power steering systems.
2Reliability
If multiple electromagnetic relays are used to control three-phase brushless motor circuits, then each relay can be optimized for its specific circuit, but the space occupied by multiple relays increases
Solution Approach 1:
The patent merges the functionality of multiple separate relays into a single integrated relay unit. The relay assembly includes both a first circuit with normally-open contacts and a second circuit with normally-closed contacts, controlled by a common coil assembly. This consolidation reduces the number of discrete relay components needed in the system, thereby reducing the total space occupied while maintaining reliable control of all motor circuits.
3Volume of moving object
If the relay is miniaturized to reduce component density, then the relay size decreases, but the current-carrying capability and contact resistance performance deteriorate
Solution Approach 1:
The patent applies local quality optimization to the contact structures. The contact assemblies are specifically designed with attention to local contact geometry and material properties to minimize contact resistance. The normally-open and normally-closed contacts are configured with appropriate contact pressures and surface areas to ensure low resistance connections despite the compact overall relay size.
Solution Approach 2:
The contact surfaces are designed with preliminary action features such as pre-contact pressure and surface preparation to ensure optimal electrical connection from the outset. The contact assemblies are configured to establish reliable electrical contact before full operation begins, minimizing contact resistance in the miniaturized relay structure.
4Productivity
If the relay structure is simplified to improve manufacturing and assembly, then productivity increases, but the ability to withstand shock and vibration deteriorates
Solution Approach 1:
The patent employs segmentation by dividing the relay into distinct modular components: a coil assembly, a first contact assembly with normally-open contacts, and a second contact assembly with normally-closed contacts. These segmented modules can be manufactured separately and assembled together, improving productivity while allowing each module to be optimized for its specific mechanical and electrical requirements, including shock and vibration resistance.
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 design achieves a space-saving, high-capacity relay capable of controlling two circuits with low resistance and stable contact force, enhancing interrupting capability and durability against automotive vibrations.
Implementation Method 1
an electro-magnet block having an iron core around which a coil is wound
Implementation Method 2
an armature that is placed in a position being opposite to another end of the iron core and is attracted by the energized iron core
Data Source
AI summary
An electromagnetic relay is provided which is small in size and is capable of controlling two circuits of an ordinarily-open contact, which has a large current-carrying capacity and high interrupting capability, and which is excellent in resistance against shock and vibration. Movable contactors are held, through bow-shaped movable contactor springs, to two -shaped holding frames each being electrically separated and being mechanically connected via a card made of a highly heat-resistant resin in a card block. Thick-plate shaped movable contacts, which are attached to the movable contactors in a fixed manner, are electrically connected or disconnected to fixed contacts in a base block, in synchronization with operations of an armature of an electro-magnet block. In order to improve a current-carrying capability and interrupting capability, there are provided two pieces of ordinarily-open contacts which are connected in series to each other, and between which an interval is doubled, in each of two circuits.