Brushed Motor Brush Card Structure to Prevent Commutator Pin Collisions

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Solution Overview

Problem

Conventional brushed motors suffer from damage and performance issues when overturned due to rattling of the armature causing collisions between the commutator's wiring pin and electronic components like the brush, leading to destruction and operational failures.

Innovation Solution

A brushed motor design featuring a convex portion on the brush card that contacts the commutator first when the armature is pulled upwards, preventing collisions between the commutator pin and the brush, and allowing for integration or separate fixing of the convex portions without altering existing brush card molds, thus avoiding damage and maintaining performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor is overturned and inverted, then the armature rattles and the commutator pin collides with the brush, but this leads to destruction of the brush and internal structure affecting motor performance

Engineering Contradiction:

Improvemotor performanceVSAvoidcollision damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The convex portion is pre-positioned on the brush card to contact the commutator body first before any harmful collision can occur. This preliminary protective contact prevents the commutator pin from striking the brush, eliminating the harmful effect before it can cause damage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The convex portion acts as an intermediary protective element between the commutator pin and the brush. When the motor is overturned, the convex portion intercepts the commutator body, preventing direct contact between the pin and brush, thus protecting the brush from collision damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a convex portion is added to the brush card to prevent collision, then protection is provided, but the brush card structure becomes more complex

Engineering Contradiction:

Improvebrush protectionVSAvoidbrush card structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protective function is segmented from the main brush card structure by adding a separate convex portion. This modular addition provides protection without requiring complete redesign of the brush card, minimizing the increase in structural complexity while achieving the protective function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of making the commutator pin shorter or moving the brush away to prevent collision, the solution inverts the approach by adding a convex portion to the brush card that actively contacts the commutator body first. This reverse thinking simplifies the overall structure compared to alternative solutions that would require more significant modifications.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS11824420B2Brushed motor and electrical product

Publication Date: 2023.11.21 NIDEC CORP(JP)

AI summary

A brushed motor includes a shaft, an armature around the shaft, a commutator on one side of the armature in an axial direction, a brush card on one side of the commutator in the axial direction, and a housing accommodating a portion of the shaft, the armature, the commutator, and a portion of the brush card. A convex portion positions corresponding to the commutator in the axial direction on a surface of the brush card on one side facing the commutator, which has a main body portion around the shaft and a pin bent from an end of the main body portion on the other side in the axial direction toward an outer side in a radial direction and one side in the axial direction. A distance between the pin and a brush on the brush card is larger than that between the main body portion and the convex portion.