Terminal Block Nut Stepped Portion Resin Cut-Off
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Solution Overview
Problem
Conventional terminal blocks experience reduced heat radiation performance due to resin films forming on fastening surfaces, which impede direct contact between conductors and nuts, leading to inefficient heat transfer and potential damage from increased pressing forces during insert molding.
Innovation Solution
A terminal block design featuring a nut with a stepped portion on its outer peripheral fastening surface, an insulating plate, and a heat sink, where the stepped portion is pressed by a resin cut-off part in the mold to ensure reliable resin cut-off and prevent resin film formation, maintaining direct contact and enhancing heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressing forces of resin cut-off parts are increased to reliably cut off resin, then resin film formation is prevented, but the insulating member may be squeezed to be fractured or the fastening surfaces may be damaged
Solution Approach 1:
The resin cut-off parts are designed to press only specific local areas (the insulating member and regions adjacent to the fastening surfaces) rather than the entire fastening surfaces. This localized pressing approach concentrates the cutting action on where resin needs to be removed while distributing the pressing force to avoid damaging the fastening surfaces and insulating member structure.
Solution Approach 2:
The pressing action is segmented into specific zones: the resin cut-off parts press the insulating member and adjacent regions separately from the fastening surfaces. This segmentation allows independent control of resin cut-off effectiveness and fastening surface protection, resolving the contradiction between reliable resin removal and preventing damage.
2Reliability
If pressing forces of resin cut-off parts are increased to reliably cut off resin, then resin film formation is prevented, but contact areas with the busbars may be reduced
Solution Approach 1:
The resin cut-off parts apply pressing force locally to the insulating member and areas adjacent to the fastening surfaces, not on the fastening surfaces themselves. This ensures resin is reliably cut off while preserving the full contact area of the fastening surfaces for optimal busbar contact.
Solution Approach 2:
The insulating member acts as an intermediary that receives the pressing force from the resin cut-off parts. By pressing the insulating member rather than directly pressing the fastening surfaces, the system achieves reliable resin cut-off while protecting the fastening surface contact areas from damage or reduction.
3Ease of manufacture
If clearances are formed at boundaries between resin cut-off parts and fastening surfaces, then resin flow into clearances occurs, but direct contact between conductors and nuts cannot be maintained
Solution Approach 1:
The resin cut-off parts remove resin from the boundaries between themselves and the fastening surfaces by pressing the insulating member in those regions. This extraction of resin prevents it from flowing into clearances and forming films that would interfere with direct contact between conductors and nuts, maintaining heat transfer efficiency.
Solution Approach 2:
The resin cut-off parts apply preliminary pressing action to the insulating member at the boundaries before resin can flow into clearances. This preliminary anti-action prevents resin from entering the clearance spaces, ensuring that no resin films form to interrupt the direct contact and heat transfer between conductors and nuts.
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
This design improves heat radiation performance by preventing resin film formation on the nut's fastening surface, ensuring effective heat transfer from conductors to the heat sink, while maintaining contact and preventing damage to the fastening surfaces, thus enhancing the terminal block's thermal conductivity.
Implementation Method 1
at least one insulating plate sandwiched in close contact between the nut and the heat sink and adapted to transfer heat of the conductors from the nut to the heat sink
Implementation Method 2
heat transferred from the conductors to the nuts is transferred to the heat sink via the insulating member and radiated from the heat sink
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An object of the present invention is to ensure adhesion between a nut and conductors and improve heat radiation performance of a terminal block by preventing a resin film from being formed on a fastening surface of the nut. A terminal block in which conductors are placed one over another and fastened by a bolt is provided with nuts 10, each with a stepped portion 12 slightly recessed and formed at an outer peripheral part of an upper fastening surface 10A, on which the conductors are to be placed; a heat sink 40 arranged below the nuts 10; an insulating plate 20 sandwiched between the nuts 10 and the heat sink 40; and a molded resin part 60 by which three kinds of members 10, 20, 40 are integrally formed. The stepped portions 12 are pressed by resin cut-off parts 73 provided in a first mold 71 for forming an upper side of the molded resin part 60 when the molded resin part 60 is formed. Restricted surfaces 12A at outer peripheral sides of press surfaces 12B to be pressed by the resin cut-off parts 73 on the stepped portions 12 are covered by the molded resin part 60.