Rotary Electric Machine Noise Suppression via Nested Shield and Filter
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Solution Overview
Problem
Existing rotary electric devices suffer from noise propagation from the control unit to the outside, and existing solutions either fail to adequately suppress this noise or result in an increase in device size.
Innovation Solution
A rotary electric device with an electromagnetic shield covering the control unit, featuring a tubular design with a through-hole for external connections, and a filter mounted on the control board between shield portions to attenuate noise, while maintaining a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a filter and electromagnetic shield are provided to limit noise propagation, then noise suppression is improved, but device size increases
Solution Approach 1:
The electromagnetic shield is formed integrally with the housing, and the filter is mounted within the control board assembly space. The shield housing integrates the electromagnetic shielding function into the existing structural housing, nesting multiple functions (structural support, electromagnetic shielding, noise filtering) into overlapping spatial configurations rather than adding separate external components.
Solution Approach 2:
The housing serves multiple functions: it provides structural support, acts as an electromagnetic shield, and integrates mounting structures for the filter. The control board assembly serves both as the control unit carrier and as the mounting platform for the filter, eliminating the need for dedicated separate components for each function.
2Ease of operation
If the control board penetrates the electromagnetic shield, then connection is simplified, but noise leakage increases through larger through-holes
Solution Approach 1:
The filter serves as an intermediary component between the control board and the external environment. Instead of allowing direct penetration of the control board through the electromagnetic shield (which would create large noise leakage paths), the filter acts as a mediator that permits necessary signal/power passage while actively suppressing noise transmission through its filtering characteristics.
Solution Approach 2:
The electromagnetic shield maintains its integrity with minimal penetrations, and the filter is positioned at a specific location where noise suppression is most critical. The shield's protective quality is concentrated where needed, with the filter providing localized noise attenuation at the connection point rather than requiring the entire shield structure to be compromised for connectivity.
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
Effectively limits noise propagation from the control unit to the outside while preventing an increase in device size, enhancing noise suppression and reducing costs.
Implementation Method 1
a filter configured to attenuate a noise component to be propagated to the external connection terminal
Implementation Method 2
an electromagnetic shield covering the control unit
Data Source
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AI summary
A rotary electric device of the present disclosure includes: a rotary electric machine including a rotating shaft; a control unit disposed side by side with the rotary electric machine in an axial direction along an axis of the rotating shaft and configured to control the rotary electric machine; and an electromagnetic shield covering the control unit. The control unit includes a control board extending in the axial direction, an external connection terminal being connected to the control board, and a filter configured to attenuate a noise component to be propagated to the external connection terminal. The electromagnetic shield is formed in a tubular shape covering the entire control board and including a first top portion provided with a through-hole into which the external connection terminal is inserted, and a second top portion disposed closer to the rotary electric machine than the first top portion. At least a part of the filter is mounted on the control board and is disposed between the first top portion and the second top portion in the axial direction.