Electric Drive Device Thermal Management for Steering Sensors
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Solution Overview
Problem
Existing electric power steering devices face challenges in managing heat generated by switching elements, which can lead to increased temperatures and affect the accuracy of magnetic sensors, such as the rotation angle sensor, due to their proximity and the heat dissipation limitations.
Innovation Solution
The electric drive device incorporates a heat sink and adapter configuration that separates the first and second power circuits from the rotation angle sensor, utilizing raised portions and depressed portions on the heat sink to enhance heat dissipation and maintain a distance between heat-generating components and the sensor, thereby reducing temperature rises and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If switching elements are disposed symmetrically on both sides of the rotation angle sensor to achieve compact layout, then the device complexity is reduced, but the temperature of the rotation angle sensor increases due to heat from both sides
Solution Approach 1:
The patent extracts the heat-generating switching elements from the symmetric arrangement around the sensor and relocates them to one side only. This removes the harmful thermal influence from both sides while preserving the compact layout benefit, directly resolving the contradiction between device complexity and sensor temperature.
Solution Approach 2:
The patent applies asymmetry by deliberately arranging the first and second switching elements on opposite sides of the circuit board rather than symmetrically around the sensor. This asymmetric layout reduces thermal impact on the sensor while maintaining effective heat dissipation paths, solving the temperature issue without significantly increasing complexity.
2Temperature
If heat sink is added to improve heat dissipation, then the temperature of power circuits is reduced, but the device complexity increases due to additional components
Solution Approach 1:
The patent merges the heat dissipation function with the existing circuit board structure by integrating heat dissipation fins directly into the board design. This combination eliminates the need for separate heat sink components while achieving effective heat dissipation, thus reducing device complexity while improving temperature control.
Solution Approach 2:
The circuit board is designed to serve multiple functions: electrical connection, mechanical support, and heat dissipation. By making the circuit board multi-functional with integrated heat dissipation features, the patent avoids adding separate heat sink components, thereby reducing device complexity while improving thermal management.
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 effectively dissipates heat from the power circuits, reduces the impact of magnetic fields on the rotation angle sensor, and enhances the accuracy of the sensor's detection, preventing temperature-induced errors and maintaining reliable operation.
Implementation Method 1
heat sink... enhance heat dissipation
Implementation Method 2
heat sink... dissipates heat from the power circuits
Data Source
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AI summary
An electric drive device and an electric power steering device that reduce temperature increase of a magnetic sensor are provided. The electric drive device includes: an electric motor; an electronic control device including a magnet at an anti-load side end of a shaft to control drive of the electric motor, and a circuit board on the anti-load side of the shaft on an extended line in an axial direction of the shaft; first coil wiring connecting the first coil groups of the electric motor to the circuit board; and second coil wiring connecting the second coil groups of the electric motor to the circuit board. Each of the first and second coil wiring includes a first portion projecting in a direction intersecting the axial direction of the shaft to the outside of the housing, and a second portion projecting outside the housing from the first portion toward the circuit board.