Segmented Shielding for Brush-Commutated Motor EMC
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Brush-commutated electric motors in motor vehicles generate electromagnetic radiation due to abrupt voltage fluctuations and spark formation during commutation, which is not effectively shielded at the connection point between the metal motor housing and plastic gear housing, posing challenges for assembly and EMC shielding.
Innovation Solution
A shielding arrangement featuring a conductive shielding hat with a cylindrical inner part and a holding section, along with electrically conductive closing elements, is designed to be easily assembled axially, providing reliable EMC shielding for the commutator while allowing the output shaft to pass through, effectively blocking electromagnetic radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a complete closing element is used to shield the end face of the motor housing, then electromagnetic radiation is effectively blocked, but assembly complexity increases and the output shaft cannot pass through
Solution Approach 1:
The closing element is segmented into multiple sections corresponding to the radial segments of the motor housing. Each section can be independently assembled and secured, allowing the output shaft to pass through the central opening while maintaining electromagnetic shielding across the entire end face surface.
2Object-affected harmful factors
If a complete closing element is used to shield the end face, then electromagnetic radiation is blocked, but manufacturing complexity increases
Solution Approach 1:
The closing element is divided into multiple separable sections that can be manufactured independently using standard machining processes. This segmentation allows each section to be produced separately and then assembled radially around the output shaft, simplifying manufacturing compared to producing a single complex piece with central openings.
3Object-affected harmful factors
If the closing element covers the entire end face, then electromagnetic shielding is effective, but the output shaft assembly is hindered
Solution Approach 1:
The closing element is segmented into radial sections with a central opening that accommodates the output shaft. The segments are arranged circumferentially around the shaft, allowing the shaft to pass through the center while the segments provide complete electromagnetic shielding across the end face surface.
Solution Approach 2:
The segmented closing elements are nested radially around the output shaft, with each segment positioned in a radial groove or secured to the motor housing. This nesting arrangement allows the shaft to pass through the central space while the segments collectively form a complete shielding barrier.
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 efficient EMC shielding of the commutator, reducing electromagnetic interference while maintaining easy assembly and ensuring the motor's operational integrity by using a shielding hat and closing elements that can be integrated into the motor housing without hindering the assembly process.
Implementation Method 1
a shielding arrangement for shielding a commutator (8) of an electric motor (2) for an actuator (1)
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4b
AI summary
The invention relates to a shielding arrangement (20) for a positioning element (1); comprising: - a shielding cap (21) which is made of an electrically conductive material and which has a cylindrical inner part (22) and a retaining section (23) with a diameter that is larger relative to the inner part (22); and - at least one electrically conductive flat closing element (24, 27, 31, 32) for placing onto an end face of the cylindrical inner part (22), said closing element (24, 27, 31, 32) closing only a part of the base of the inner part (22). The invention further relates to an electric motor (2) for an electromotive positioning element (1), comprising: - a shielding arrangement (20) according to one of the preceding claims; - a hollow cylindrical motor housing (5); and - an armature unit (7) which is inserted into the cylindrical motor housing (5) and which supports one or more wound armatures and a commutator (8) on an output shaft (3).