Steering Column Seal Structure With Thermal Expansion Escape Space
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Solution Overview
Problem
Steering column devices face challenges in maintaining high sealing performance without applying excessive load to sealing members, which can expand under high temperatures, leading to potential leakage and fitting issues.
Innovation Solution
The design incorporates an escape space between the housing and cover, allowing the sealing member to expand into this space, reducing the load on the sealing member and maintaining compression, while also facilitating easier assembly by cutting out a part of the insertion portion to prevent catching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compression amount of the sealing member is increased to improve sealing performance, then sealing performance is improved, but the filling factor becomes excessive and excessive load may be applied to the sealing member when it expands under high temperature
Solution Approach 1:
The space between the housing and cover is segmented into two distinct regions: an accommodation space for the sealing member and an escape space for thermal expansion. This segmentation allows the sealing member to be compressed sufficiently for sealing while providing a dedicated region for expansion, preventing excessive load application.
Solution Approach 2:
The invention utilizes the axial dimension between the housing and cover to create the escape space, extending the functional space in the axial direction. This dimensional approach allows the sealing member to expand axially into the escape space rather than radially compressing against the sealing surfaces, maintaining sealing effectiveness while accommodating thermal expansion.
2Reliability
If the compression amount of the sealing member is increased, then sealing performance is improved, but the volume ratio of the sealing member to the accommodation space (filling factor) increases
Solution Approach 1:
The total space between housing and cover is divided into accommodation space and escape space. The accommodation space is sized to provide appropriate compression (3-5 mm) for sealing, while the escape space accommodates expansion volume, maintaining an appropriate filling factor in the accommodation space.
Solution Approach 2:
The escape space acts as an intermediary region that absorbs the volume increase of the sealing member during thermal expansion. This intermediary space prevents the expansion from translating into excessive compression forces on the sealing surfaces.
3Ease of operation
If the escape space is provided by cutting out a part of the insertion portion, then ease of assembly is improved by preventing catching, but the structural complexity increases
Solution Approach 1:
A portion of the insertion portion is extracted or cut out to form the escape space. This removal of material eliminates the catching issue during assembly while the escape space itself serves the dual function of providing thermal expansion room and maintaining compression on the sealing member.
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 enhances sealing performance by reducing excessive load on the sealing member, maintaining compression, and improving ease of assembly by preventing the cover from catching during fitting.
Implementation Method 1
when the sealing member expands under a high temperature environment
Data Source
AI summary
A steering column device includes a steering shaft; and a steering column. The steering column includes a housing, a cover, and a sealing member. The housing includes an inclined portion having an inclined surface with an inside diameter increasing from a first side to a second side, the inclined surface contacting the sealing member from the first side. The cover includes a facing portion having a facing surface contacting the sealing member from the second side, and an insertion portion having an outer peripheral surface contacting the sealing member from an inner peripheral side. The sealing member is accommodated in an accommodation space defined by the inclined surface, the facing surface, and the outer peripheral surface. An escape space continuous with the accommodation space is provided between the housing and the cover, the escape space being located closer to the first side than the inclined surface is.