Steering Rack Bushing Slit Design for Assembly
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Solution Overview
Problem
Existing steering systems face challenges in assembling the steering operation shaft bushing to the housing without separating it into multiple pieces, leading to uneven wearing and potential collisions between components, which complicates the assembly process and can result in noise.
Innovation Solution
A steering system design that incorporates a tubular steering operation shaft bushing with a collar, a through slit, and at least one first non-through slit, where the length of the slit configuration is optimized to reduce the outer diameter of the collar across its circumference, allowing for a single-piece assembly without separating the bushing into multiple pieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the steering operation shaft bushing is provided with only one through slit, then the bushing remains as a single piece avoiding complicated assembly, but the outer diameter is not sufficiently reduced making it difficult to insert into the housing
Solution Approach 1:
The invention divides the single through slit into multiple segments: a through slit extending axially and multiple radially extending slits that do not extend through the entire thickness. This segmentation allows the collar's outer diameter to be reduced sufficiently for insertion while keeping the bushing as a single integrated piece, avoiding the need to separate it into multiple bushing pieces
Solution Approach 2:
The invention transitions from a single axial dimension slit to a multi-dimensional slit configuration by adding radial slits that extend from the axial end face toward the opposite axial end face. This multi-dimensional approach reduces the outer diameter more effectively than a single through slit while maintaining structural integrity
2Length of moving object
If the steering operation shaft bushing is provided with through slits at two or more locations in the circumferential direction, then the outer diameter is sufficiently reduced for insertion, but the bushing is separated into multiple pieces complicating assembly
Solution Approach 1:
Instead of creating separate bushing pieces with through slits at multiple circumferential locations, the invention segments the slit structure itself by combining axial and radial slits. The radial slits extend from the axial end face but do not penetrate through the entire thickness, preventing separation into multiple pieces while achieving sufficient outer diameter reduction
Solution Approach 2:
The radial slits are configured to extend sufficiently far from the axial end face to reduce the outer diameter to a level that allows insertion into the housing before assembly is completed. This preliminary diameter reduction ensures the collar can be inserted without forcing while maintaining the single-piece structure
3Ease of manufacture
If the steering operation shaft bushing is provided with only one through slit, then assembly is simplified, but uneven wearing and collisions between components occur
Solution Approach 1:
The combination of axial and radial slits creates a segmented slit pattern that distributes stress and wear more uniformly across the collar structure. The radial slits particularly help by creating multiple stress relief zones that prevent concentration of wear at single locations, improving reliability while maintaining assembly simplicity
Solution Approach 2:
The radial slits are positioned to create local stress relief zones at specific locations on the collar. This local quality modification ensures more uniform wear distribution across the collar's circumference, preventing uneven wearing and potential collisions during operation
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A steering system (1) includes a rack shaft (13), a tubular rack housing (20), and a tubular rack bushing (80). The rack housing (20) holds the rack shaft (13) such that the rack shaft (13) is movable in an axial direction (A). The rack bushing (80) is interposed between the outer surface of the rack shaft (13) and the inner surface of the rack housing (20) in a region adjacent to an axial end of the rack housing (20). The rack bushing (80) supports the rack shaft (13) such that the rack shaft (13) is slidable in the axial direction (A). The rack housing (20) includes an annular groove (28) on the inner surface of the rack housing (20). The rack bushing (80) includes a collar (82), a through slit (83), and first non-through slits (84). The collar (82) protrudes radially outward from substantially the entire circumference of the rack bushing (80). The collar (82) is fitted into the annular groove (28). The through slit (83) passes through the rack bushing (80) in the axial direction (A). Each first non-through slit (84) extends in the axial direction (A) such that the first non-through slit (84) passes through a portion of the rack bushing (80) whose axial position corresponds to the axial position of the collar (82). Selected drawing: FIG. 2