Columnar Fastening Member with Projection for Semiconductor Bus Bar
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing fastening methods for power semiconductor devices often degrade the electrical connection between terminal plates and semiconductor elements due to applied forces during screw tightening, and the fastening members can detach from the case when upward forces are applied, leading to instability in the terminal plate's position.
Innovation Solution
A columnar fastening member with a first hole, thread, planar portion, and projection is used, which suppresses the clockwise force applied during screw tightening and enhances friction within the accommodating portion, preventing detachment and ensuring reliable electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a screw is fastened to the terminal plate to fix the bus bar, then the bus bar can be securely fixed with small contact resistance, but the clockwise force applied to the screw causes the terminal plate to be removed from the semiconductor element, degrading the electrical connection state
Solution Approach 1:
A fastening member (bush) is introduced as an intermediary component between the terminal plate and the case. This bush has a projection that fits into a groove on the terminal plate, and when the screw is tightened, the projection absorbs the clockwise rotational force, preventing it from being transmitted to the terminal plate and semiconductor element interface, thus maintaining electrical connection reliability while still achieving secure bus bar fixation
Solution Approach 2:
The clockwise rotational force that was previously harmful (causing terminal plate removal) is converted into a beneficial function by the projection structure. The projection engages with the groove and converts the rotational torque into a locking mechanism that secures the terminal plate in position, transforming the harmful rotational force into a stabilizing effect
2Device complexity
If the fastening member is merely inserted into the case, then the structure is simple, but the fastening member can be detached from the case when upward force is applied, causing the terminal plate to be removed from the semiconductor element
Solution Approach 1:
The fastening member features an asymmetric projection with a specific shape that corresponds to a matching groove in the case. This asymmetric design creates a one-way mechanical interlock where the projection can be inserted easily but prevents removal when upward force is applied, as the geometry of the projection-groove interface blocks the removal path while maintaining structural simplicity
Solution Approach 2:
The fastening member is segmented into distinct functional portions: an insertion portion that fits into the case, a projection portion that engages with the terminal plate groove, and a threaded portion for screw attachment. This segmentation allows each portion to perform its specific function independently, providing reliable retention without requiring complex overall structure
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 provides improved reliability by maintaining the electrical connection between the terminal plate and semiconductor element, preventing degradation and ensuring stable fastening, thus enhancing the overall reliability of the semiconductor device.
Implementation Method 1
a projection which suppresses a clockwise force applied when a screw is fastened
Implementation Method 2
enhances friction within the accommodating portion, preventing detachment
Data Source
AI summary
Provided is a fastening member which is a columnar fastening member, and the fastening member includes: a first hole provided in a direction parallel to a height direction of the fastening member; a thread on a side surface of the first hole; a planar portion around the first hole; and a projection between the planar portion and the first hole.