Steering Drive Partition Wall for Control Unit Protection
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Solution Overview
Problem
Conventional electric power steering apparatuses face issues with foreign matter intrusion into the control unit due to the exposure of the output shaft, which can lead to contamination from abrasion powder and water, compromising the reliability and durability of the system.
Innovation Solution
A drive device with a rotating electric machine and a control unit separated by a partition member, where the control unit is positioned on the opposite side of the output, and a connection line takeout part with a seal member to prevent foreign matter intrusion, along with a partition wall that isolates the shaft and control unit, and a frame member acting as both an outer shell and heat sink to dissipate heat from electronic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the output shaft is exposed from the control unit side of the bearing holder, then the connection between the motor and control unit is simplified, but foreign matter such as abrasion powder and water can intrude into the control unit
Solution Approach 1:
The bearing holder is divided into a motor unit side and a control unit side by the partition wall, creating separate sealed spaces. This segmentation allows the output shaft to be isolated from the control unit while maintaining structural simplicity, preventing foreign matter intrusion without requiring complex sealing mechanisms.
Solution Approach 2:
The partition wall acts as an intermediary barrier between the motor unit and control unit. It separates the spaces while allowing the connection line to pass through, providing both protection against foreign matter and maintaining electrical connectivity without exposing the control unit to contaminants.
2Temperature
If a separate heat sink is added to dissipate heat from electronic components, then heat dissipation performance is improved, but the number of components and device volume increase
Solution Approach 1:
The partition wall is designed to serve dual functions: it acts as both a separator between the motor unit and control unit, and as a heat sink for dissipating heat from electronic components. This merging of functions eliminates the need for a separate heat sink component, reducing overall device complexity and volume while maintaining effective heat dissipation.
Solution Approach 2:
The partition wall is designed with heat dissipation capabilities (through protrusions or extended surfaces) to perform multiple functions: structural separation, electrical isolation, and thermal management. This multi-functionality reduces the total component count while addressing both protection and heat dissipation requirements.
3Reliability
If the control unit is positioned on the opposite side to the output of the rotating electric machine, then foreign matter intrusion is prevented, but the connection line routing becomes more complex
Solution Approach 1:
The partition wall with its integrated takeout part serves as an intermediary structure that manages the connection line routing. The connection line passes through the partition wall at a designated location, which simplifies the routing path compared to alternative configurations and maintains protection while enabling electrical connectivity.
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 solution effectively prevents foreign matter and water intrusion into the control unit, enhancing the reliability and durability of the electric power steering apparatus while reducing the number of components and device volume, particularly along the axial direction, and allowing for use in engine rooms.
Implementation Method 1
heat of at least a part of the electronic components that are surface-mounted on one surface of the substrate that face the rotating electric machine is dissipated to the partition member
Data Source
AI summary
A drive device includes a control unit with a substrate. The control unit is disposed on an opposite side of a motor relative to an output shaft of the motor. The substrate has electronic components mounted on the substrate. A motor line connects the substrate and a winding. A frame member bears the surface-mount electronic components on a first surface of the substrate. A bearing holder holds a bearing that bears a shaft. A motor line takeout part allows the motor line to extend toward the control unit. A partition wall separates the shaft and the control unit at a radial inside position of the motor line takeout part. Such a structure prevents foreign matter from intruding into a control unit accommodating space.