Brush Motor Commutator Segmentation to Reduce Wear
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Solution Overview
Problem
In motors with brushes, electrical sparking between the brush and segments leads to wear and shortening of the brush, complicating the winding process and increasing manufacturing time due to the need for winding coils in both forward and reverse directions.
Innovation Solution
A motor design with a commutator having 2m×n segments, where m is an odd number and n is a natural number, featuring a brush group with cyclic potential changes and coils connected in series through segments, allowing only continuous winding in one direction on some teeth and reverse winding on others, separated by specific electric angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the number of segments is increased to twice the number of teeth to reduce brush wear from sparking, then brush lifespan is improved, but the winding process becomes more complicated and manufacturing time increases
Solution Approach 1:
The commutator is divided into 2m×n segments where m is an odd number and n is a natural number, creating a segmented structure that reduces potential difference between adjacent segments. This segmentation allows the brush to contact segments with smaller voltage differences, reducing sparking and wear while maintaining a manageable winding structure.
Solution Approach 2:
Coils are selectively wound in different directions based on their positional relationship with magnetic poles. Specifically, coils at positions separated by 360×i degrees (where i is a natural number ≤ n-1) are wound in opposite directions, while other coils follow a uniform winding direction. This localized variation in winding quality optimizes torque production while simplifying the overall winding process.
2Reliability
If coils are wound in both forward and reverse directions on each tooth to achieve proper electrification switching, then torque production is maintained, but the winding process complexity increases
Solution Approach 1:
Instead of winding all coils in both directions, the patent applies different winding directions only to specific coils based on their angular position. Coils at positions separated by 360×i degrees are wound in opposite directions, while other coils use a uniform winding direction. This localized approach maintains torque reliability while significantly reducing winding complexity.
Solution Approach 2:
The patent inverts the conventional approach by having most coils wound in a single direction, with only specific coils wound in the opposite direction. This inversion of the traditional double-direction winding method simplifies the overall process while maintaining the necessary electrification switching functionality through the segmented commutator design.
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
Significantly reduces brush wear from sparking and simplifies the winding process, thereby extending brush lifespan and reducing manufacturing time and costs.
Implementation Method 1
The rotation section includes an armature core having m×n teeth which are attached on the shaft and radially extend in the radial direction, a plurality of coils respectively provided on the m×n teeth, and a commutator electrically connected to the plurality of coils. The static section includes field magnets having 2n magnetic poles facing the m×n teeth in the radial direction.
Data Source
AI summary
A motor includes an armature core having m×n teeth (m is an odd number ≧3, and n is a natural number ≧2), a plurality of coils, and a commutator. The motor further includes field magnets including 2n magnetic poles and at least a first-potential brush and at least a second-potential brush. The commutator includes a segment group defined by 2m×n segments. Only the coil defined by winding a continuous conducting wire in a predetermined winding direction is disposed in each of k teeth among the m×n teeth, and only the coil defined by winding the continuous conducting wire in a direction reverse to the predetermined winding direction is disposed in each of teeth disposed at a position separated from each of the k teeth at 360×i degrees (i is a natural number ≦(n−1)) of electric angles.