Steering Rack Boot Venting Through Bush Restriction Groove
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Solution Overview
Problem
The existing steering devices suffer from extreme deformation and damage of boots due to hermetically sealed spaces that prevent air from entering or leaving, leading to uneven expansion and contraction during the reciprocating movement of the rack shaft.
Innovation Solution
The steering device incorporates a design where either the bush or the housing has a protrusion part that fits into a restriction groove on the other component, allowing the spaces inside the first and second boots to constantly communicate with each other, enabling air flow and preventing extreme deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the space inside the boot is hermetically sealed, then the boot is protected from external contaminants, but the boot undergoes extreme deformation and damage due to inability to accommodate volume changes during rack shaft reciprocation
Solution Approach 1:
The sealing system is segmented into multiple zones: the boot itself remains sealed, while a separate compensation chamber connected via communication passage handles volume changes. This segmentation allows the boot to maintain its protective sealing function while the compensation system absorbs expansion/contraction forces, preventing extreme deformation.
Solution Approach 2:
A communication passage acts as an intermediary element between the boot interior and the compensation chamber. This passage allows air to flow as a mediator, equalizing pressure and accommodating volume changes without requiring the boot material itself to deform extensively, thus preserving boot integrity.
2Reliability
If grease or lubricating oil is present between the bush and housing, then the rack shaft is properly lubricated, but the space inside the boot becomes hermetically sealed causing deformation
Solution Approach 1:
The air compensation function is extracted from the boot structure itself and placed into a separate compensation chamber. The communication passage connects this external chamber to the boot interior, allowing the boot to maintain its lubricated sealing environment while the extracted compensation system handles volume changes, preventing shape distortion.
Solution Approach 2:
Different regions of the system have different functional qualities: the boot region maintains hermetic sealing for lubrication protection, while the compensation chamber region provides air communication for volume compensation. This local differentiation allows each region to optimize its specific function without compromising the other.
3Adaptability or versatility
If the boot material is made of rubber or resin, then the boot provides flexible coverage and sealing, but the boot becomes extremely deformed and damaged when hermetically sealed during reciprocating movement
Solution Approach 1:
The compensation chamber is prepared in advance as a cushioning volume that can absorb pressure changes before they affect the boot structure. The communication passage allows air to move into or out of this pre-prepared chamber, cushioning the boot against extreme deformation during rack shaft reciprocation while maintaining the boot's flexible sealing properties.
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 suppresses extreme deformations of the boots by allowing air to flow between the boot spaces, maintaining their integrity and ensuring the steering device functions properly.
Implementation Method 1
a space inside the first boot and a space inside the second boot constantly communicate with each other via the restriction groove
Data Source
AI summary
A steering device includes a rack shaft that turns wheels, a bush slidably support the rack shaft, tie-rods joined to the rack shaft, boots that cover a joining portion that joins the rack shaft and the tie-rod. A protrusion part is formed on either one of the bush and a rack housing so as to protrude toward the other. A restriction groove into which the protrusion part is inserted is formed on the other. A space inside the first boot and a space inside the second boot constantly communicate with each other via the restriction groove.