Motor Housing Threaded Mounting for Compact Steering Drive
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Solution Overview
Problem
Existing drive devices with electric motors face challenges in size reduction due to the need for flange portions and screw bolts to fix the motor housing to the installation subject, which increase the outer diameter and hinder compact design.
Innovation Solution
A drive device with a motor housing featuring a coaxial screw thread engaging portion that threadably engages with the installation subject, eliminating the need for flange portions and screw bolts, allowing for a smaller outer diameter and improved heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flange portions and screw bolts are used to fix the motor housing to the installation subject, then the fixing reliability is improved, but the outer diameter of the motor housing increases
Solution Approach 1:
The patent merges the fixing function into the motor housing structure itself by providing an engaging portion with a screw thread directly on the motor housing. This eliminates the need for separate flange portions and screw bolts, combining multiple components into one integrated structure that maintains fixing reliability while reducing outer diameter.
Solution Approach 2:
The patent extracts and eliminates unnecessary components (flange portions and screw bolts) from the fixing system. By removing these separate fixing elements and integrating the threading function directly into the motor housing, the design achieves compact dimensions while preserving the essential fixing function.
2Strength
If flange portions are provided in the motor housing for screw bolt insertion, then the fixing strength is improved, but the device complexity increases
Solution Approach 1:
The patent combines the housing structure and fixing mechanism into a single integrated component. The engaging portion with the screw thread is formed directly on the motor housing, eliminating the need for separate flange portions and fasteners, thereby reducing structural complexity while maintaining fixing strength.
Solution Approach 2:
The motor housing serves multiple functions: it protects the motor unit and simultaneously provides the fixing function through its integrated engaging portion with screw thread. This multi-functionality eliminates the need for dedicated fixing components, reducing overall device complexity.
3Reliability
If multiple fixing components (screw bolts, flange portions) are used, then the fixing reliability is improved, but the component management becomes more difficult
Solution Approach 1:
The patent removes unnecessary fixing components from the system. By eliminating flange portions and screw bolts, the design reduces the number of parts that need to be managed, assembled, and maintained, while the integrated engaging portion maintains sufficient fixing reliability for the application.
Solution Approach 2:
By merging the fixing function into the motor housing structure itself, the patent reduces the total component count. The engaging portion with screw thread integrated into the housing eliminates the need for separate fixing components, simplifying component management and assembly procedures.
Data Source
AI summary
A drive device of an electric power steering apparatus includes a motor housing fixed to a gear housing, a stator, which is received in an inside of the motor housing, a rotor, which is rotatably placed on an inner side of the stator, and a shaft, which is rotated integrally with the rotor. The motor housing includes an engaging portion. The engaging portion has a thread, which is coaxial with a rotational axis of the shaft and is threadably engaged with the gear housing.