Commutator Motor Brush Holder Radial Movement Restriction
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Solution Overview
Problem
Existing commutator motor designs require additional processes and increased manufacturing costs due to the need for a movement restricting portion, and they face challenges in minimizing size due to clearance requirements for brush holder movement, which complicates assembly and increases radial dimensions.
Innovation Solution
A commutator motor design that incorporates brush holders with guide walls and grooves on an annular holder plate, where the brush holders' radially outer ends abut the end frame or yoke, restricting outward movement without the need for a separate movement restricting portion, allowing for reduced assembly processes and minimized size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate movement restricting portion is added to restrict radially outward movement of brush holders, then the brush holders can be properly positioned, but the device complexity and manufacturing cost increase
Solution Approach 1:
The movement restricting function is merged into the existing holder plate structure by forming protrusions that engage with grooves in the brush holders. This eliminates the need for a separate movement restricting portion, reducing device complexity while maintaining position stability.
Solution Approach 2:
The holder plate is given multiple functions: it not only holds the brush holders in position but also restricts their radially outward movement through integrated protrusions. This multi-functionality reduces the overall number of components needed in the brush holding device.
2Ease of manufacture
If clearance is provided between brush holders and yoke to allow assembly movement, then assembly is easier, but the radial dimension of the motor increases
Solution Approach 1:
The brush holders are designed with dynamic movement capability during assembly through the groove-protrusion guidance system, allowing radial inward movement for assembly while restricting outward movement during operation. This dynamic behavior enables easy assembly without requiring excessive clearance, thus minimizing the motor's radial dimension.
3Reliability
If additional processes are added to bend up movement restricting portion, then the brush holding device can be assembled, but the productivity decreases
Solution Approach 1:
The movement restricting protrusions are pre-formed on the holder plate during its manufacturing process, rather than being bent up separately during assembly. This preliminary action eliminates additional manufacturing steps and improves productivity while ensuring reliable movement restriction.
Data Source
AI summary
In a commutator motor, a brush holding device includes a plurality of brush holders and a substantially annular holder plate. Each of the brush holders includes a holder frame, which receives a pair of brush and spring, and a bottom plate having two opposite side portions. The holder plate is disposed around a commutator and has a major surface on which a plurality of pairs of guide walls are formed; each pair of the guide walls defines a pair of grooves. The side portions of the bottom plate of each of the brush holders are respectively fit in a corresponding pair of the grooves defined by the guide walls. Each of the brush holders has a radially outer end that abuts an inner surface of a side wall of an end frame, whereby radially outward movement of each of the brush holders is restricted by the end frame.