Electric Power Steering Housing Layout for Reduced Radial Size
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Solution Overview
Problem
The existing electric power steering devices are unable to be reduced in size in the radial direction, making it difficult to fit them into limited spaces.
Innovation Solution
The design includes a first housing and a second housing with specific bolt bosses and bracket portions that allow for a compact arrangement, utilizing a spigot joint and overlapping bolt holes and threads to reduce the radial size, while maintaining structural integrity and stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the existing electric power steering device configuration is used, then the structural integrity and sealing performance are maintained, but the radial size cannot be reduced
Solution Approach 1:
The patent applies nesting by positioning the bolt holes and female thread portions within the plane area defined by connecting the second pinion shaft, first bracket hole, and second bracket hole. This nested arrangement allows the fastening features to be contained within the existing structural footprint, reducing radial size without requiring additional external space that would compromise structural integrity.
Solution Approach 2:
The patent transitions from a radial arrangement of bolt bosses to a planar arrangement within the defined plane area. By moving the fastening features into the plane defined by the bracket holes and pinion shaft rather than extending radially outward, the design reduces radial dimension while maintaining the necessary fastening functionality and structural strength.
2Area of stationary object
If the existing electric power steering device configuration is used, then the structural integrity is maintained, but the device cannot be arranged in a limited small space
Solution Approach 1:
The bolt holes and female thread portions are nested within the plane area defined by the second pinion shaft, first bracket hole, and second bracket hole. This containment strategy ensures that all fastening features fit within the existing structural envelope, reducing the overall space occupation while maintaining structural integrity through proper positioning within the defined area.
3Volume of moving object
If the bolt bosses are repositioned within the plane area, then the radial size is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the housing into distinct functional zones: the rack-bar accommodating portion, the second pinion-shaft accommodating portion, the bracket portion, and the precisely positioned bolt bosses. By segmenting these features and defining their positions relative to each other within the plane area, the design achieves compact radial dimensions while maintaining manufacturability through clear geometric relationships between segmented features.
Data Source
AI summary
An electric power steering device including a first bolt boss of a second housing provided on a first housing side relative to a worm-wheel accommodating portion of the second housing, and has a first female thread portion open on the first housing side and located within a plane area defined by connecting a second pinion shaft, a first bracket hole, and a second bracket hole; and a first bolt boss of the first housing provided to the first housing to be opposed to the first bolt boss of the second housing, and has a first bolt hole located within the plane area defined by connecting the second pinion shaft, the first bracket hole, and the second bracket hole and being formed through the first housing to be continuous with the first female thread portion of the first bolt boss of the second housing.