PMDC Motor Rotor Winding Segmentation for EPB Reliability
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Solution Overview
Problem
Traditional electric parking brake systems using permanent magnet direct current (PMDC) motors are prone to malfunction when one of the rotor windings is open-circuited, leading to reliability and safety issues during vehicle operation.
Innovation Solution
A PMDC motor design with rotor windings comprising multiple winding units, each with two coils wound about the same teeth and connected to the same commutator segments, allowing for continued functionality even if one coil is open-circuited, along with a gearbox for speed reduction and linear motion conversion, enhancing reliability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional PMDC motor rotor windings use single coil per tooth configuration, then the motor structure is simple, but the system reliability deteriorates when one coil is open-circuited
Solution Approach 1:
The rotor windings are divided into multiple winding units, with each winding unit comprising at least two coils wound about the same teeth and connected to the same commutator segments. This segmentation allows the system to tolerate coil failures while maintaining overall motor functionality.
Solution Approach 2:
Each winding unit is designed with redundant coils that have identical electrical connections to the commutator segments. This local quality uniformity ensures that any coil within a winding unit can be replaced or fail without affecting the overall motor operation, as the redundant coils maintain the electrical circuit integrity.
2Reliability
If multiple coils are wound about the same teeth in each winding unit, then the reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
Multiple coils within each winding unit are merged in terms of their electrical connections to the same commutator segments. This merging approach simplifies the manufacturing process by reducing the number of unique connection patterns that need to be implemented, while still providing redundancy for improved reliability.
3Object-affected harmful factors
If traditional single coil configuration is used, then the manufacturing process is simple, but the vibration and noise increase when coil failure occurs
Solution Approach 1:
The patent implements redundant coils in advance within each winding unit, creating a cushioning effect against potential coil failures. When one coil becomes open-circuited, the redundant coil continues to function, preventing the sudden increase in vibration and noise that would occur with complete motor failure or unbalanced operation.
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 motor maintains performance with minimal loss even when one coil is open-circuited, improving the reliability and safety of the electric parking brake system by ensuring continued functionality and reduced vibration and noise.
Implementation Method 1
a motor for actuating brake members of an electric parking system, comprising a stator and a rotor rotatably mounted to the stator; the rotor comprising a shaft, a commutator and a rotor core fixed to the shaft, and rotor windings wound about teeth of the rotor core and electrically connected to segments of the commutator
Data Source
AI summary
A motor for actuating brake members of an electric parking (EPB) system, includes a stator and a rotor rotatably mounted to the stator. The rotor has a shaft, a commutator, a rotor core fixed to the shaft, and rotor windings wound about teeth of the rotor core and electrically connected to segments of the commutator. The rotor windings have a plurality of winding units and each of the winding units have at least two coils. The coils of each winding unit are wound about the same teeth and are connected to a same pair of segments.