Electric Drive Device Radial Size Reduction via Axial Control Unit Mounting
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Solution Overview
Problem
The existing electric power steering devices face challenges in size reduction and component count, particularly in the radial direction, due to the integration of redundant electronic control units and the need for additional housing and sealing components, which increases size and complexity.
Innovation Solution
The electric drive device integrates redundant electronic control units directly onto a heat radiation base body within the motor housing, eliminating the need for a separate housing and using a cover that is liquid-tightly connected without bolts, thereby reducing size and component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate housing is used to accommodate the electronic control unit, then the electronic control unit is protected and organized, but the radial size of the electric drive device increases
Solution Approach 1:
The electronic control unit is integrated directly into the motor housing structure, eliminating the need for a separate housing. The control unit is mounted on the end surface of the motor housing, merging two previously separate components (motor housing and control unit housing) into one unified structure, thereby reducing radial size while maintaining protection and organization of the electronic control unit.
2Reliability
If multiple separate components (housing, seals, bolts) are used to accommodate and secure the electronic control unit, then the control unit is securely mounted and sealed, but the component count increases
Solution Approach 1:
The motor housing is designed to serve multiple functions simultaneously: it accommodates the electronic control unit, provides sealing through an integrated seal member, and secures the control unit through integrated fixing structures. This merging of multiple separate components (housing, seals, bolts) into a unified motor housing structure reduces component count while maintaining secure mounting and sealing functionality.
Solution Approach 2:
The motor housing is designed as a multi-functional component that simultaneously serves as the structural housing for the motor, the mounting base for the electronic control unit, the sealing element, and the fixing structure. This multi-functionality eliminates the need for separate dedicated components for each function, thereby reducing overall component count while maintaining reliability.
3Ease of operation
If the electronic control unit is arranged along the radial direction in the housing, then the control unit is easily accessible and mounted, but the radial size of the device increases
Solution Approach 1:
The electronic control unit is arranged along the axial direction of the motor shaft rather than the radial direction. By changing the mounting orientation from radial to axial, the control unit is positioned at the end surface of the motor housing, which maintains ease of accessibility and mounting while avoiding radial size increase. This dimensional repositioning effectively transfers the control unit to a different spatial dimension where it does not interfere with radial space constraints.
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 achieves size reduction in the radial direction, simplifies the structure, and reduces the component count, enhancing safety and efficiency by eliminating unnecessary housing and sealing components while maintaining effective heat radiation.
Implementation Method 1
one electronic control unit of a redundant system, the one electronic control unit arranged along a direction in which a heat radiation base body extends and having a board that is fixed to the heat radiation base body with thermal conduction to the heat radiation base body allowed
Data Source
AI summary
A heat radiation base body extending in a direction of a rotation shaft of an electric motor close to the rotation shaft is provided at an end surface of a motor housing accommodating the electric motor. A board of one electronic control unit of a redundant system is fixed to the heat radiation base body along the direction in which heat radiation base body extends with thermal conduction allowed. A board of the other electronic control unit of redundant system is fixed to the heat radiation base body along a direction in which the heat radiation base body extends, so as to face the board of one electronic control unit, with thermal conduction allowed. A cover covering these is fixed to an end surface of the motor housing without a bolt. Thus, a housing accommodating the electronic control unit is not necessary. A sealing part is only the connecting portion between the motor housing and cover, thereby eliminating additional structure of the sealing part, sealing component required for seal and bolt.