Electric Power Steering Housing Layout for Sealing and Assembly
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Solution Overview
Problem
Existing electric power steering devices face challenges in ensuring sealing between housings accommodating the belt and pulleys while minimizing parallelism between mounting surfaces of fixed portions, which affects the assembly and performance of the device.
Innovation Solution
The electric power steering device employs a three-housing configuration, where a first housing supports the rack shaft, a second housing covers the conversion unit and supports the electric motor, and an intermediate housing is positioned between them to cover the rack shaft, ensuring sealing and reducing parallelism between mounting surfaces by using O-rings and strategically designed connecting portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two housings are used to accommodate the belt and pulleys, then assembly and maintenance become easier, but sealing between connecting portions becomes difficult to ensure
Solution Approach 1:
The housing is divided into multiple segments (first housing, second housing, and intermediate housing) that can be assembled separately and then connected. This segmentation allows for easier assembly and maintenance while the intermediate housing ensures proper sealing at the connecting portions through its specific structure designed to mate with the first and second housings.
2Stability of the object's composition
If multiple fixed portions are provided on the housing, then mounting stability improves, but parallelism between mounting surfaces becomes difficult to maintain
Solution Approach 1:
The housing with multiple fixed portions is segmented into multiple housings (first, second, and intermediate housings). Each housing can be manufactured and assembled separately, making it easier to maintain parallelism between mounting surfaces of each individual housing while still achieving stable mounting through the combined structure of all housings working together.
Data Source
AI summary
An electric power steering device includes: an electric motor; a rack shaft configured to move axially; a conversion unit configured to convert rotational driving force of the moto into movement of the rack shaft; a first housing configured to cover a part of an outer surface of the rack shaft and including a first leg portion fixed to a vehicle; a second housing configured to cover a part of the outer surface of the rack shaft and including a fourth connecting portion covering the conversion unit and a second leg portion fixed to the vehicle; and an intermediate housing disposed between the first and second housings and configured to cover a part of the outer surface of the rack shaft 3 and including a motor support portion supporting the motor.