Steering Apparatus Support Shaft Backlash Control
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Solution Overview
Problem
The existing steering apparatuses face issues with backlash in the axial direction of the support shaft due to variations in component dimensions, which can affect the breaking load during secondary collisions, especially when the support shaft is made of a resin member that may break.
Innovation Solution
A steering apparatus configuration that includes a support shaft with a biasing member integrated as a single unit, where the biasing member biases the support shaft in a specific direction, and a positioning mechanism to prevent backlash, allowing for easier assembly and reduced manufacturing costs by forming the support shaft and biasing member from a single material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the support shaft is made of a resin member that can break at the time of secondary collision, then the support shaft can be designed to break at designated positions for safety, but backlash in the axial direction occurs due to variation of component dimensions
Solution Approach 1:
The patent applies preliminary action by pre-positioning the support shaft in the axial direction using positioning portions provided on the fastened portions. This preliminary positioning ensures that the support shaft is correctly located before the secondary collision occurs, preventing backlash and ensuring consistent breaking load at designated positions.
Solution Approach 2:
The patent changes the dimensional parameters of the support shaft and fastened portions by providing positioning portions that constrain the axial position. This parameter control eliminates dimensional variations that cause backlash, ensuring reliable breaking at designated positions while maintaining manufacturing feasibility.
2Ease of manufacture
If the support shaft and biasing member are made as separate components, then assembly flexibility is maintained, but assembly complexity increases and manufacturing costs increase
Solution Approach 1:
The patent merges the support shaft and biasing member into a single integrated component. This combination eliminates the need for separate assembly steps, reduces the number of parts, and lowers manufacturing costs while maintaining the functional requirements of both components.
Solution Approach 2:
The integrated support shaft and biasing member performs multiple functions simultaneously: providing structural support, applying biasing force, and positioning in the axial direction. This multi-functionality reduces the overall device complexity and simplifies the assembly process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively prevents backlash and ensures reliable breaking of the support shaft at designated positions during secondary collisions, stabilizing the shear load and reducing manufacturing costs through integrated components.
Implementation Method 1
a biasing member provided between the first end portion of the support shaft and one of the side plates opposed to the first end portion, the biasing member being configured to bias the support shaft in a biasing direction directed toward the second end portion of the support shaft
Data Source
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AI summary
A steering apparatus includes a steering shaft (3); a column jacket (8) including an outer jacket (12) including a slit (26) and a pair of fastened portions (19), and an inner jacket (11); a bracket (17); a fastening mechanism (18); an engaged tooth formation member (40) including at least one engaged tooth (41) and fixed to the inner jacket (11); a support shaft (50) including end portions supported by support holes (38) of the fastened portions (19); an engaging tooth formation member (70) including an engaging tooth (72a) that engages with the engaged tooth (41); and a biasing member (90) configured to bias the support shaft (50) in a biasing direction. One of the fastened portions (19) or a member (39) supported by the one fastened portion (19) includes a positioning portion (39a) configured to position the support shaft (50) in the biasing direction.