Steering Housing Guide Mechanism for Misalignment Tolerance
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Solution Overview
Problem
Conventional housing structures for power steering apparatuses require precise alignment and polishing of elliptically shaped fitting surfaces, which is time-consuming and labor-intensive, and may suffer from misalignment due to manufacturing or assembly errors, especially when attaching leg portions to vehicle body seats.
Innovation Solution
A housing structure that allows the first and second housings to rotate relative to each other around the axis of a shaft, facilitated by guide portions that engage along the circumferential direction, eliminating the need for elliptic polishing and enabling easy alignment of leg portions with vehicle body seats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If inner fitting portion and outer fitting portion are formed all along opening edges of housings to enable precise combination, then housing alignment precision is improved, but machining time and effort increase due to polishing requirements
Solution Approach 1:
The fitting structure is segmented into discrete positioning pins rather than continuous elliptical fitting surfaces. The positioning pins are distributed at specific locations on the mating surfaces, providing precise alignment without requiring polishing of entire elliptical surfaces. This segmentation transforms a time-consuming continuous machining operation into simpler discrete pin installation.
Solution Approach 2:
The complex elliptical fitting surface is extracted and replaced with simple cylindrical positioning pins. The essential alignment function is maintained through the pins, while the time-consuming polishing operation is eliminated. The positioning pins are inserted through holes in the housing to provide the necessary alignment without requiring precision machining of the entire mating surface.
2Manufacturing precision
If positioning pins are used to combine housings precisely, then housing alignment precision is improved, but assembly time increases due to pin attachment and alignment requirements
Solution Approach 1:
The positioning pin holes are pre-formed in the housing components during manufacturing. The positioning pins are pre-prepared as separate elements that can be easily inserted. This preliminary preparation eliminates the need for complex real-time alignment operations during assembly, as the pins are simply inserted into pre-positioned holes to achieve the required precision.
3Ease of manufacture
If leg portions are formed on housings to enable fixed fastening to vehicle body, then housing attachment capability is improved, but alignment difficulty increases when leg seats are misaligned due to manufacture or assembly errors
Solution Approach 1:
The housing combination is made dynamic by allowing relative rotation around the shaft axis while maintaining positional relationship through the positioning pins. This dynamic capability enables the leg portions to be rotated into proper alignment with misaligned leg seats on the vehicle body, while the positioning pins maintain the essential positional relationship and prevent excessive movement. The system transitions from a fixed rigid connection to a flexible dynamic one that can accommodate misalignment.
Data Source
AI summary
A housing structure includes first and second housings and first and second rotation transmitting members. The first and second housings house a shaft. The first rotation transmitting member is provided coaxially with the shaft. The second rotation transmitting member is arranged so as to transmit power to the first rotation transmitting member. The first and second housings are combined with each other so that mating surfaces of the first and second housings that are unparallel to an axis of the shaft are contacted. The first housing includes a first guide portion that protrudes from the mating surface of the first housing. The second housing includes a second guide portion that engages with the first guide portion. The first and second guide portions are engaged with each other along a circumferential direction of the axis and guide relative rotation of the first housing and the second housing around the axis.