Forcibly Guided Relay Miniaturization with Clapper Contactor
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Solution Overview
Problem
The miniaturization of relays for safety circuits poses challenges in reducing tolerance ranges, leading to smaller distances between current-conducting parts, which complicates creepage and sparking distances, contact spring dimensions, and force conditions between contact springs and drives, making it difficult to achieve compact designs while meeting standards like EN 50205 for current-carrying capacity.
Innovation Solution
A forcibly guided relay with an electromagnetic drive, featuring a clapper-type contactor and multiple contact pairs, where the contact springs are anchored with feet perpendicular to the housing, allowing for reduced dimensions and simplified adjustment, utilizing a coil with a high-grade magnetic core and optimized winding for low power consumption and high current-carrying capacity, and incorporating a drive cam and separating walls to extend creepage and sparking distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If relay dimensions are reduced for miniaturization, then the relay size decreases, but the tolerance ranges and distances between current-conducting parts are reduced, making it difficult to meet creepage and sparking distance requirements
Solution Approach 1:
The patent repositions the coil from a traditional lateral arrangement to a longitudinal arrangement along the core axis. This dimensional change allows the magnetic field to be generated more efficiently along the length of the relay, enabling compact transverse dimensions while maintaining adequate internal spacing for creepage and sparking distances. The contact pairs are arranged in a plane perpendicular to the core axis, optimizing the use of available space.
Solution Approach 2:
The relay is divided into functionally independent modules: the electromagnetic drive unit (coil and core), the contactor unit (clapper and contact pairs), and the housing structure. This segmentation allows each module to be optimized independently - the drive unit can be miniimized while the contact unit maintains necessary spacing for safety distances, and vice versa.
2Volume of moving object
If contact spring dimensions are reduced to fit compact relay, then the relay size decreases, but the force conditions between contact springs and drive become critical with reduced tolerance margin
Solution Approach 1:
The patent changes the geometric parameters of the contact springs, specifically making them extend parallel to the core axis rather than perpendicular. This orientation change, combined with anchoring them at locations along a side of the housing, optimizes the mechanical leverage and force transmission. The contact springs engage the drive cam at points that maximize force efficiency while minimizing the required spring dimensions.
Solution Approach 2:
The drive cam acts as an intermediary element between the electromagnetic drive and the contact springs. It converts the linear motion of the drive arm into the appropriate motion for actuating the contact pairs, providing mechanical advantage and ensuring reliable force transmission even with reduced contact spring dimensions.
3Length of stationary object
If relay dimensions are reduced to meet 12 mm height requirement, then the relay fits standard housing, but the adjustment of contact springs becomes more of a problem
Solution Approach 1:
The contact springs are designed to be self-adjusting through their engagement with the drive cam. As the drive cam moves through its cycle, it automatically sets the correct contact pressure and positioning of the contact springs without requiring manual adjustment. This self-service mechanism eliminates the need for post-assembly adjustment procedures.
Solution Approach 2:
The contact springs are pre-positioned and pre-tensioned during assembly by engaging them with the drive cam in a predetermined sequence. The drive cam geometry is designed to automatically set the correct contact spring tension and position, performing the adjustment action during the assembly process itself rather than requiring separate adjustment steps after assembly.
4Adaptability or versatility
If multiple contact pairs are added to increase functionality, then the relay current-carrying capacity increases, but the distances between current-conducting parts are reduced, complicating creepage and sparking distances
Solution Approach 1:
The contact pairs are arranged in a plane perpendicular to the core axis, utilizing the transverse dimension of the relay housing. This arrangement allows multiple contact pairs to be positioned at adequate spacing from each other and from current-conducting parts of the drive mechanism, maintaining required creepage and sparking distances while accommodating 3, 4, 6, or 8 contact pairs in a compact configuration.
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 relays with very small dimensions, meeting EN 50205 standards for 6 to 10 A current-carrying capacity, with reduced power consumption and simplified adjustment, eliminating the need for post-assembly contact spring adjustments, while maintaining high conductivity and adherence to printed circuit board spacing requirements.
Implementation Method 1
The drive usefully comprises a coil with an elongate core of magnetic soft iron, and a winding present around the core
Data Source
AI summary
A forcibly guided relay is disclosed, with a housing, whose height is smaller than its width and whose width is smaller than its length. With this, the relay comprises an electromagnetic drive filling the length or the width of the relay, with a clapper-type contactor which comprises a drive arm which extends in the direction of the core and at its free end cooperates with a drive cam; several contact pairs, which are in each case formed by a contact spring and a fixed or spring-like counter-contact said contact springs extending in the direction of the core, and with the drive ends being in a forcibly guided engagement with the drive cam. With this relay a break contact is arranged directly next to the contactor, whose contact spring in each position of the contactor runs approximately parallel to the drive arm of the clapper-type contactor; and a separating wall is present between the clapper-type contactor and the break-contact, at least in the region between the contact heads of the break-contact, and the drive cam, runs approximately parallel to the drive arm of the clapper-type contactor in the activated position spread away from the coil.