Brush Card Assembly Stabilization and Heat Dissipation in DC Motors
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Solution Overview
Problem
Conventional brush holding bodies in motors experience instability and inadequate gas flowability, leading to potential heat generation issues due to insufficient support and gas circulation.
Innovation Solution
The motor design incorporates a brush card assembly with a back cover and housing that includes specific gaps and flow holes to enhance the support and flowability of gas and liquid, stabilizing the brush card assembly and improving heat dissipation by ensuring communication between the first and second gaps and an outer space through flow holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the brush holding body uses only a fixing flange clamped between housing and cover, then the structure is simple, but the support state becomes unstable during motor rotation
Solution Approach 1:
The brush holding body is divided into multiple functional parts: a fixing flange for basic mounting, a fixing protrusion that engages with a recess in the cover, and a positioning protrusion that fits into a positioning hole. This segmentation allows each part to contribute to overall stability without significantly increasing structural complexity.
Solution Approach 2:
The positioning protrusion and fixing protrusion are integrated into the brush holding body structure, with the positioning protrusion nested within the overall assembly. The cover includes a positioning hole that receives the positioning protrusion, creating a nested relationship that enhances stability while maintaining compact design.
2Volume of stationary object
If the brush holding body has limited gas flowability, then the structure remains compact, but heat generation increases due to insufficient gas circulation
Solution Approach 1:
The cover is designed with differentiated local properties: a first portion that covers part of the brush holding body to maintain compactness, and a second portion that includes a through-hole to enable gas flow. This local quality differentiation allows the same component to serve both compactness and heat dissipation functions.
Solution Approach 2:
The through-hole in the cover acts as an intermediary element that facilitates gas circulation between the interior and exterior of the brush holding body. This mediator allows heat dissipation without requiring major structural changes or increasing the overall volume.
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 configuration stabilizes the brush card assembly, reduces noise and vibration, and effectively suppresses heat generation within the motor by improving gas and liquid flowability, thereby enhancing the motor's performance and reliability.
Implementation Method 1
flowability of gas around the brush holding body is insufficient, which may cause heat generation
Implementation Method 2
flowability of gas around the brush holding body is insufficient, which may cause heat generation
Data Source
AI summary
A motor includes a rotor, a back cover, a housing, and a brush card assembly. The rotor includes a core fixed to a shaft, a coil that magnetizes a core, and a commutator connected to the coil. The back cover includes a back cover bottom surface portion, and a back cover cylindrical portion on an outer periphery of the back cover bottom surface portion to have a cylindrical shape. The brush card assembly includes a brush card bottom surface portion spaced apart from the back cover bottom surface portion in an axial direction through a first gap. The brush card bottom surface holds brushes and includes a nip portion nipped by the back cover and the housing, an outer peripheral wall spaced apart from the back cover cylindrical portion in a radial direction through a second gap, and contact portions contacting the back cover cylindrical portion.