Motor Control Unit Radial Sensor Arrangement
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Solution Overview
Problem
Conventional motor control units with multiple sensors face challenges in miniaturization due to large sensor installation areas on the circuit substrate, which affects detection precision and increases manufacturing complexity and costs.
Innovation Solution
The motor control unit incorporates a sensing unit with a sensor magnet featuring concentrically disposed magnetization belts and sensor elements arranged radially, allowing for closer proximity without separate placement, thereby reducing dead space and maintaining detection precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are arranged on the circuit substrate to improve rotation angle detection precision, then the detection precision is improved, but the occupation area of sensor installation parts becomes large
Solution Approach 1:
The patent transitions from arranging sensors in a planar configuration on the circuit substrate to a three-dimensional configuration where sensors are positioned around the rotor in different radial directions. This spatial dimensionality change allows sensors to be closer together without increasing the footprint area on the circuit substrate, resolving the contradiction between detection precision and occupation area.
Solution Approach 2:
The patent integrates the sensors and their mounting structure within the existing motor assembly, nesting the sensing components within the motor's radial space. The sensors are positioned in the gap between the stator and rotor, utilizing the existing three-dimensional space rather than requiring additional planar area on the circuit substrate.
2Measurement precision
If sensors are arranged separated from each other to maintain detection precision, then the detection precision is maintained, but dead spaces between sensors increase
Solution Approach 1:
By arranging sensors in different radial directions around the rotor rather than in a linear array on the substrate, the patent eliminates dead spaces between sensors. The three-dimensional radial arrangement allows sensors to be positioned at the vertices of a polygon around the rotor, maximizing space utilization and eliminating gaps that would exist in planar arrangements.
3Area of stationary object
If sensors are placed closer together to reduce occupation area, then the occupation area is reduced, but detection precision may deteriorate
Solution Approach 1:
The patent maintains detection precision despite reduced occupation area by utilizing three-dimensional spatial arrangement. Sensors positioned at different radial distances and angular positions around the rotor can be physically closer in terms of substrate footprint while maintaining optimal spacing for magnetic field detection, as the radial dimension provides additional separation space.
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 minimizes the occupation area of sensor elements on the circuit substrate while maintaining high detection precision for motor rotation angles, reducing manufacturing complexity and costs by eliminating the need for precise position management of sensor elements.
Implementation Method 1
a first sensor element and a second sensor element configured to convert a periodical magnetic signal caused by a rotation of the sensor magnet into a digital signal
Data Source
AI summary
A motor control unit includes a sensing unit and a driver unit. The sensing unit includes a sensor magnet to rotate in synchronization with a rotation of a rotor included in a motor, and a first sensor element and a second sensor element to convert a signal caused by a rotation of the sensor magnet into a digital signal. The driver unit controls the motor based on output signals of the elements. The sensor magnet includes a first magnetization belt and a second magnetization belt where a plurality of magnetic poles is arranged in a peripheral direction of the rotor. The belts are concentrically disposed to cause arrangements of the magnetic poles to be shifted by a predetermined angle in a peripheral direction. The elements are arranged in a radial direction of the rotor.