Brushed Motor Brush Configuration for Torque Stability
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Solution Overview
Problem
The existing motor designs with three brushes (common, low-speed drive, and high-speed drive) experience significant resistance fluctuation due to changes in the number of effective coils, leading to torque fluctuations and noise, especially when brushes short-circuit adjacent segments, affecting the motor's performance and vibration.
Innovation Solution
The motor is designed with a configuration where the common brush, low-speed drive brush, and high-speed drive brush are spaced and positioned such that they do not simultaneously short-circuit adjacent segments, ensuring a consistent number of effective coils by alternating and controlling the short-circuit states, thereby minimizing resistance fluctuation and torque fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the three brushes are arranged to short-circuit adjacent segments, then the motor can operate at different speeds, but the number of effective coils changes significantly causing resistance fluctuation and torque fluctuations
Solution Approach 1:
The patent applies local quality by making each brush have a specific width and position configuration tailored to its function. The common brush, low-speed drive brush, and high-speed drive brush are positioned at different locations with different widths to control which segments they short-circuit at different rotation angles, thereby maintaining stable effective coil numbers while enabling speed control
Solution Approach 2:
The patent changes the parameters of brush width and brush position to resolve the contradiction. By carefully selecting the width and angular position of each brush, the design ensures that when one brush short-circuits segments, another brush compensates to maintain a consistent number of effective coils, thus stabilizing resistance while preserving speed adaptability
2Device complexity
If the brush width and position are not optimized, then the motor structure is simple, but torque fluctuations and noise increase due to changing effective coil numbers
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-positioning the brushes during the design phase. The brush widths and positions are determined in advance to ensure that during operation, the brushes will short-circuit segments in a controlled sequence that maintains stable effective coil numbers, thereby preventing torque fluctuations and noise before they occur
3Speed
If all three brushes simultaneously short-circuit adjacent segments, then the motor can achieve high-speed operation, but the number of effective coils decreases causing performance instability
Solution Approach 1:
The patent applies periodic action by designing the brush positions and widths so that they short-circuit segments in a periodic sequence as the commutator rotates. This ensures that at any given time, the number of effective coils remains stable, while still enabling high-speed operation through the periodic engagement of the high-speed drive brush
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 motor's performance by maintaining a consistent number of effective coils, reducing torque fluctuations and noise, and ensuring efficient operation across different speed settings.
Implementation Method 1
A motor includes at least one magnet, an armature, a common brush, a low-speed drive brush, and a high-speed drive brush. The magnet forms four or more magnetic pole portions. The armature includes a rotation shaft, an armature core fixed to the rotation shaft and having a plurality of teeth, a coil wound around the teeth
Implementation Method 2
The common brush, low-speed drive brush, and high-speed drive brush are spaced apart and arranged along the circumferential direction of the rotation shaft in slidably contact with the commutator
Data Source
AI summary
A motor including a magnet, an armature, a common brush, a low-speed drive brush, and a high-speed drive brush is disclosed. The magnet forms four or more magnetic pole portions. The armature includes a rotation shaft, an armature having fourteen teeth, a coil wound around the teeth, and a commutator having fourteen segments arranged in a circumferential direction of the rotation shaft. The common brush, low-speed drive brush, and high-speed drive brush are spaced apart and arranged in the circumferential direction of the rotation shaft and each have a width in the circumferential direction of the rotation shaft. The number of teeth is the same as the number of segments. When P represents the number of magnetic pole portions of the magnet and S represents the number of teeth, (2S/P) is an odd number. The width of each brush and the location of the brush in the circumferential direction are set so that the three types of brushes, which are the common brush, the low-speed drive brush, and the high-speed drive brush, all do not simultaneously short-circuit two of the segments that are adjacent to each other in the circumferential direction.