Brushed Motor Constant-Load Spring for Stable Brush Pressure
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Solution Overview
Problem
Existing brushed electric motors experience a significant difference in pressure between the initial and final stages of brush wear, leading to increased friction and reduced efficiency and lifespan due to the use of coil or torsion springs, necessitating high initial pressure settings.
Innovation Solution
The electric motor design incorporates a constant load spring with two spiral portions and a pressing member that applies uniform pressure to the brush, ensuring consistent contact with the commutator without requiring the brush to be shortened, thereby maintaining motor lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a coil spring or torsion spring is used as the brush spring, then the brush can be pressed against the commutator, but the pressure difference between initial and final stages is large, causing increased friction and reduced efficiency
Solution Approach 1:
The patent changes the spring mechanism from a coil spring or torsion spring to a constant load spring with a specific spiral geometry. This parameter change in the spring design enables uniform pressure application throughout brush wear, maintaining constant force while reducing energy loss from friction variations.
2Force
If the spiral portion of the brush spring is arranged behind the rear end surface of the brush, then the constant load can be applied to the brush, but the brush length must be shortened, reducing motor lifespan
Solution Approach 1:
The patent repositions the spiral portion of the constant load spring from a location behind the brush (requiring brush shortening) to a location on the front end surface side of the brush. This spatial reconfiguration in another dimension allows the spring to apply constant load while preserving the full brush length, thereby extending motor lifespan.
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 maintains consistent brush pressure throughout the motor's lifespan, reducing friction and enhancing efficiency by avoiding the need to shorten the brush, thus extending the motor's operational life.
Implementation Method 1
a constant load spring including a first spiral portion and a second spiral portion each made of a strip-shaped wire material wound in a spiral shape
Data Source
AI summary
An electric motor includes a rotor including a rotating shaft extending in an axial direction, a commutator attached to the rotating shaft, a brush including a front end surface coming into contact with the commutator and a rear end surface positioned on a side opposite to the front end surface, a constant load spring including a first spiral portion and a second spiral portion each made of a strip-shaped wire material wound in a spiral shape, and including a fixed end on the front end surface side of the brush, and a pressing member coming into contact with the rear end surface of the brush to press the brush against the commutator with a load from the constant load spring.