Drive Unit Fastener for Modular Control Unit
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Solution Overview
Problem
Conventional electric power steering devices require a larger motor size due to the internal coupling of the bus bar and winding wire, making it difficult to separate the motor and control unit without removing the drive unit from the column shaft, which complicates maintenance and assembly.
Innovation Solution
A drive unit design featuring a motor with a stator and rotor housed in a motor case, where the control unit is positioned on one end, and a fastener secures both mechanical and electrical connections between the motor and control unit, allowing for easy detachment and reattachment without removing the motor from the column shaft, using a receptacle and receptacle holder for secure alignment and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bus bar and winding wire are coupled inside the motor case, then the electrical connection is secure, but the motor size increases and the control unit cannot be easily separated
Solution Approach 1:
The patent divides the electrical connection system into separate components: a connector with a first connection terminal on the motor side and a second connection terminal on the control unit side. This segmentation allows the control unit to be detached from the motor without affecting the motor case size, while maintaining reliable electrical connections through the connector interface.
2Reliability
If the bus bar and winding wire are coupled inside the motor case, then the electrical connection is secure, but the control unit cannot be easily removed without removing the drive unit from the column shaft
Solution Approach 1:
The connector is designed as a separate, detachable component that interfaces between the motor and control unit. This allows the control unit to be independently removed and replaced by simply detaching the connector, without needing to remove the entire drive unit from the column shaft, thereby improving maintenance ease while maintaining connection reliability.
Solution Approach 2:
The connector is extracted from the motor case interior and positioned externally, allowing it to serve as an independent detachment interface. This extraction enables the control unit to be separated from the motor assembly without affecting the motor case or its internal structure, facilitating easy control unit replacement while maintaining secure electrical connections when assembled.
3Reliability
If a screw fastener is used to secure the bus bar on the winding wire terminal, then the electrical connection is secure, but the structure becomes complex and requires larger motor size
Solution Approach 1:
The patent combines the electrical connection function and mechanical fastening function into a single integrated connector component. The connector simultaneously provides electrical connectivity through its terminals and mechanical securing through its fastening structure, eliminating the need for separate bus bars, terminals, and screw fasteners, thereby reducing overall structural complexity while maintaining connection reliability.
Data Source
AI summary
A drive unit has a motor, a control unit, and a fastener. The motor is housed in a motor case, and includes a stator, a rotor, and a shaft. The stator has winding wires that are wound therein and are electrically coupled to motor wires. The rotor is disposed inside of the stator and the shaft is disposed in and coupled to the rotor, such that the rotor and shaft rotate, as one, within the stator. The control unit includes a semiconductor module with a switching element, a connection terminal that electrically couples the switching element with other devices, and a control unit case to house the semiconductor module. The fastener is disposed in the control unit case, such that the fastener couples the motor and the control unit, and electrically couples the motor wire and the connection terminal.