Integrated EPS Motor Assembly with Perpendicular PCB
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Solution Overview
Problem
Motor assemblies for electric power steering systems, particularly those with brushless motors, face packaging challenges due to their large size and separate sensors, leading to limited positioning options, high costs, and complex installations, as they interfere with other vehicle components.
Innovation Solution
A motor assembly for electric power steering systems that integrates a torque and angle sensor on a printed circuit board within an enclosure, along with a worm shaft and worm gear, allowing for compact packaging and versatile installation by measuring differential angles between input and output shafts, and includes a motor position sensor for precise rotational position measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motor assemblies and sensors are kept separate, then each component can be optimized independently, but the overall system size increases and packaging becomes difficult
Solution Approach 1:
The patent combines the motor assembly and sensors into a single integrated unit. The motor housing serves as the enclosure that contains both the motor and the circuit card assembly with torque and angle sensors, eliminating the need for separate sensor housings and reducing overall system volume while maintaining component functionality.
Solution Approach 2:
The circuit card assembly with sensors is nested within the motor housing enclosure. The printed circuit board is positioned inside the motor housing, utilizing the existing motor structure to house additional components, thereby reducing the external dimensions of the overall assembly.
2Measurement precision
If separate sensors are used, then measurement functions are independent, but installation complexity and positioning options are limited
Solution Approach 1:
The torque sensor and angle sensor are integrated into a single circuit card assembly that is mounted within the motor housing. This consolidation reduces the number of separate installation steps and simplifies positioning, as the entire sensor assembly is installed as one unit rather than requiring separate mounting for each sensor.
3Power
If large motor assemblies are used, then motor performance is maintained, but packaging space requirements increase
Solution Approach 1:
The motor assembly is designed with a compact configuration where the circuit card assembly is nested within the motor housing. The printed circuit board is positioned to utilize space efficiently within the existing motor envelope, allowing the system to maintain motor performance while reducing the overall packaging footprint.
Solution Approach 2:
The printed circuit board is oriented perpendicular to the rotational axis of the steering column, utilizing the radial dimension of the motor assembly to house the circuit card. This dimensional arrangement allows the circuit card assembly to be accommodated within the motor housing without increasing the axial length or overall volume of the motor assembly.
4Adaptability or versatility
If integrated sensor and motor assembly is used, then packaging constraints are reduced, but manufacturing complexity increases
Solution Approach 1:
The motor and circuit card assembly are manufactured as a single integrated unit, which simplifies installation by reducing the number of separate components to be assembled. The integrated design allows the entire assembly to be positioned and installed as one unit, enhancing adaptability to different installation locations while the manufacturing complexity is managed through modular design principles.
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 integrated solution reduces packaging constraints, enhances versatility, lowers costs, and simplifies installation by compactly housing sensors and motors, improving the overall efficiency and adaptability of EPS systems.
Implementation Method 1
a torque and angle sensor disposed upon a printed circuit board. The torque and angle sensor is configured to measure a differential angle between rotational positions of the output shaft and an input shaft
Implementation Method 2
a motor configured to rotate a motor shaft to apply a drive torque to an output shaft of a steering column
Implementation Method 3
a worm shaft coupled to rotate with the motor shaft, the worm shaft having a worm disposed helically thereabout for driving a worm gear coupled to the output shaft
Data Source
AI summary
Technical solutions for a motor assembly for an electric power steering system are provided. The motor assembly comprises a motor configured to rotate a motor shaft to apply a drive torque to an output shaft of a steering column. The motor assembly also comprises a circuit card assembly including a torque and angle sensor disposed upon a printed circuit board and configured to measure a differential angle between rotational positions of the output shaft and an input shaft. The printed circuit board of the circuit card assembly is disposed perpendicular to a rotational axis of the steering column. The motor assembly also comprises an enclosure coupled to the motor and containing the circuit card assembly and a worm shaft coupled to rotate with the motor shaft and having a worm disposed helically thereabout for driving a worm gear coupled to the output shaft.