Brush Motor Winding Segmentation for EPS Reliability
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Solution Overview
Problem
Conventional brush motors used in electric power steering systems suffer from significant performance degradation when a winding element breaks, affecting the reliability and safety of the system.
Innovation Solution
A brush motor design featuring a rotor with first and second winding elements, where each winding element is connected in series through commutator segments, forming closed loops in adjacent wire slots, enhancing reliability by minimizing the impact of a broken winding element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional rotor winding with simplex lap winding is used, then the motor structure is simple and easy to manufacture, but the reliability deteriorates significantly when a winding element breaks
Solution Approach 1:
The rotor winding is segmented into multiple independent winding elements distributed across different wire slots. Each winding element is electrically connected through commutator segments, forming a modular structure where failure of one element does not propagate to others, thereby improving reliability while maintaining manufacturing simplicity
Solution Approach 2:
Different wire slots are configured to receive different winding elements with specific electrical connection characteristics. The commutator segments provide localized electrical connections that isolate failures to specific regions, ensuring that local defects do not affect the entire winding system
2Reliability
If winding elements are electrically connected through commutator segments in separate closed loops, then the reliability improves by isolating failures, but the device complexity increases
Solution Approach 1:
The commutator segments serve multiple functions: they provide electrical connections between different winding elements, isolate failures to specific closed loops, and maintain the rotational electrical connection interface. This multi-functionality reduces the need for additional isolation components, thereby limiting complexity increase
Solution Approach 2:
The commutator segments act as intermediary components that mediate electrical connections between stator brushes and rotor winding elements. They enable the formation of separate closed loops while maintaining a unified rotational interface, thus improving reliability without proportionally increasing device complexity
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
The design enhances the motor's reliability by ensuring that even if a winding element is broken, the motor performance is less affected, making it suitable for applications requiring high reliability, such as electric power steering systems.
Implementation Method 1
a rotor winding wound around the rotor core... The rotor winding comprises a plurality of winding elements... Adjacent teeth define therebetween wire slots for receiving the winding elements
Implementation Method 2
The stator includes a plurality of electric brushes. The commutator comprises a plurality of commutator segments... The first winding elements are connected in series through the commutator segments
Data Source
AI summary
An electric power steering system and its brush motor are disclosed. The brush motor includes a stator and a rotor rotatably mounted to the stator. The rotor includes a rotary shaft, a commutator and a rotor core fixed to the rotary shaft, and a rotor winding wound around the rotor core. The commutator includes a plurality of commutator segments. The rotor core includes a plurality of teeth. The rotor winding includes a plurality of winding elements. Adjacent teeth define therebetween wire slots for receiving the winding elements. The winding elements include a plurality of first winding elements and a plurality of second winding elements. The first winding elements are connected in series through the commutator segments. The second winding elements are connected in series through the commutator segments. The first winding elements and the second winding elements are received in different wire slots. Implementation of the present invention can improve the reliability of the product.