Commutator Motor Brush Holder Segmented Guide Webs
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Solution Overview
Problem
Existing commutator motors with rectangular carbon brush holders have limited robustness in guiding brushes, resulting in unstable current ripple signals, which are essential for accurately determining the rotor's rotational position, and this stability decreases over the service life of the brushes.
Innovation Solution
The commutator motor incorporates a brush holder with radial guide webs and a spring element that securely engages with the brush, providing stable guidance and maintaining constant brush contact pressure, ensuring a robust and precise current ripple signal throughout the motor's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rectangular carbon brush holders with large tolerances are used, then the device complexity is reduced and ease of manufacture is improved, but the guidance precision of brushes deteriorates and measurement precision of rotor position deteriorates
Solution Approach 1:
The brush holder is segmented into multiple functional surfaces: a bearing surface for supporting the brush, and multiple guide surfaces (first guide surface, second guide surface, third guide surface) for precise positioning. This segmentation allows each surface to perform its specific function optimally, achieving both ease of manufacture and high measurement precision.
Solution Approach 2:
Different regions of the brush holder are given different geometric properties tailored to their functions. The bearing surface provides radial support, while the guide surfaces provide tangential guidance with specific tolerances. This local differentiation of geometric quality enables precise brush guidance without requiring the entire holder to have high manufacturing complexity.
2Device complexity
If rectangular carbon brush holders with large tolerances are used, then the device complexity is reduced, but the reliability of current ripple signal deteriorates
Solution Approach 1:
The brush holder geometry is segmented into distinct functional zones with specific tolerance requirements. The bearing surface and guide surfaces are designed with differentiated tolerances, allowing reliable brush guidance without requiring the entire component to have high manufacturing complexity.
Solution Approach 2:
The guide surfaces are given tighter tolerances locally where precision is critical for brush alignment, while other regions maintain larger tolerances. This local quality differentiation ensures reliable current ripple signals without unnecessarily increasing overall device complexity.
3Measurement precision
If play in brush guidance is reduced, then the measurement precision of rotor position is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The guidance function is segmented across multiple surfaces rather than relying on a single tight-tolerance feature. The bearing surface and multiple guide surfaces work together to reduce play, distributing the manufacturing precision requirements across several features rather than concentrating them in one location.
Solution Approach 2:
Different guide surfaces have different tolerance specifications tailored to their functions. The first guide surface and second guide surface have tolerances optimized for their specific guidance roles, allowing reduced play in critical areas without requiring uniformly high manufacturing precision throughout the entire brush holder.
4Reliability
If the brush contact pressure is kept constant over service life, then the reliability of current ripple signal is improved, but the device complexity increases due to spring element
Solution Approach 1:
The spring element automatically compensates for brush wear over the service life, maintaining constant contact pressure without requiring external adjustment or intervention. This self-service mechanism ensures reliable current ripple signals throughout the brush lifespan while adding minimal complexity compared to alternative adjustment mechanisms.
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 design enhances the guidance of brushes within the holders, allowing for a reliable and precise determination of the rotor's position by minimizing play and maintaining consistent brush contact pressure, thus improving the robustness of the current ripple signal.
Implementation Method 1
The at least one spring element is preferably designed to act on the at least one brush with a second predetermined spring force in the direction of the collector. This makes it possible to provide a commutator motor in which a substantially constant brush advance force and thus a substantially constant brush contact pressure on the collector are achieved both when new and over the service life of the brush.
Data Source
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AI summary
In the case of a commutator motor with a commutator (270), which has a collector (280) which, at a collector contact surface (289), is in sliding contact with associated brushes (250, 290), wherein at least one brush (250) is arranged in an associated brushholder (220), the brushholder (220) has at least one guide web (231, 237), which is aligned in the radial direction of the collector (280) and engages in at least one guide groove (252, 254) provided in the at least one brush (250).