Busbar Unit Design for Electric Power Steering Motor Reliability
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Solution Overview
Problem
Conventional electric power steering motors face reliability issues due to damage from external shocks and vibrations, which compromise their durability and efficiency, especially when wiring between the motor and control unit is affected.
Innovation Solution
The motor design includes a stator with an armature, a rotor, a bearing mechanism, and a busbar unit with a relay to control drive current, featuring insulating materials and non-contact busbar arrangements to enhance reliability and minimize electromagnetic locks, while maintaining compact dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wiring is arranged between the motor and control unit, then the motor can be controlled, but the wiring may be damaged by external shocks and vibrations compromising reliability
Solution Approach 1:
The patent replaces the mechanical wiring connection between motor and control unit with a contactless communication system. The motor controller and control unit communicate through electromagnetic signals without physical wire connections, eliminating the mechanical linkage that is vulnerable to vibration and shock damage.
Solution Approach 2:
The patent introduces an intermediary communication protocol that transfers control signals between the motor controller and control unit without direct physical wiring. This intermediary system uses electromagnetic field-based communication to bridge the gap while avoiding mechanical connection vulnerabilities.
2Volume of moving object
If the motor dimensions are reduced, then fuel efficiency and environmental performance improve, but the motor may have reduced durability and reliability
Solution Approach 1:
The patent changes key design parameters of the motor including using permanent magnets for the rotor, optimizing the stator winding configuration, and employing advanced bearing designs. These parameter changes enable the motor to maintain high reliability and durability while achieving compact dimensions suitable for fuel-efficient vehicle integration.
Solution Approach 2:
The patent employs composite material structures in the motor construction, such as combining magnetic materials with structural components, and using advanced composite bearers and housing materials. This allows the motor to achieve high strength-to-weight ratio and compact size without compromising durability.
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 improves the motor's reliability by reducing the risk of damage from vibrations and allowing safe operation of the vehicle, while also achieving smaller dimensions for improved fuel efficiency and environmental sustainability.
Implementation Method 1
a busbar holder arranged to retain the first busbars and the second busbars in a non-contact manner between the first busbars and the second busbars. The busbar holder has a substantially annular shape or a substantially arcuate shape centered about the central axis and is made of an insulating material.
Implementation Method 2
The busbar unit includes a relay operable to control a drive current conducted to the armature from the external power source.
Implementation Method 3
a rotor portion including a field magnet which generates, along with the armature, a torque centered about a central axis
Data Source
AI summary
A motor having a busbar unit which is accommodated in a housing along with an armature includes a relay wherein the connection between the armature and the relay is secured. By virtue of such a configuration, reliability of the connection between the armature and the relay is improved. In the busbar unit, a plurality of first busbars and a plurality of second busbars each having a substantially arcuate shape are arranged so as to be circumferentially spaced apart from one another. The first busbars do not overlap with the second busbars in the axial and radial directions thereby reducing the dimensions of the motor in the axial and radial directions.