Steering Column Seal Structure for Thermal Expansion Control
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Solution Overview
Problem
Steering column devices face challenges in maintaining high sealing performance without applying excessive load on sealing members, which can expand under high temperature conditions, leading to potential leakage and reduced fitting ease.
Innovation Solution
The design incorporates an escape space between the housing and cover, allowing the sealing member to expand into this space, reducing excessive load and maintaining compression, while also facilitating easier fitting by cutting out a part of the insertion portion.
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 environment
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 expansion. This segmentation allows the sealing member to have sufficient compression for sealing while providing a dedicated region for thermal expansion, preventing excessive load application.
Solution Approach 2:
The escape space extends the accommodation space in the axial direction, creating a continuous volume that accommodates both the compressed sealing member and its potential expansion. This dimensional extension resolves the conflict between maintaining compression and allowing expansion.
2Reliability
If the compression amount of the sealing member is increased to improve sealing performance, then sealing performance is improved, but the compression amount decreases when the sealing member expands under high temperature
Solution Approach 1:
The escape space is designed beforehand to accommodate the expected thermal expansion of the sealing member. By providing this pre-planned expansion region, the system cushions the effect of expansion and prevents loss of compression in the sealing portion, maintaining sealing performance throughout temperature variations.
3Ease of operation
If the escape space is provided by cutting out a part of the insertion portion, then ease of fitting is improved, but the structural complexity of the cover increases
Solution Approach 1:
The insertion portion is pre-formed with the cutout portion during manufacturing, creating a built-in guide feature that facilitates proper alignment and insertion of the cover onto the housing. This preliminary structural feature eliminates the need for separate alignment tools or complex assembly procedures.
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 preventing excessive load on the sealing member and maintaining its compression, thereby improving the device's ability to prevent leakage and ease of assembly.
Implementation Method 1
when the sealing member expands under a high temperature environment
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A steering column device includes a steering shaft (2); and a steering column (4). The steering column (4) includes a housing, a cover, and a sealing member (45). The housing includes an inclined portion (61) having an inclined surface (63) with an inside diameter increasing from a first side to a second side, the inclined surface (63) contacting the sealing member (45) from the first side. The cover includes a facing portion having a facing surface (65) contacting the sealing member (45) from the second side, and an insertion portion (33) having an outer peripheral surface contacting the sealing member (45) from an inner peripheral side. The sealing member (45) is accommodated in an accommodation space (S1) defined by the inclined surface (63), the facing surface (65), and the outer peripheral surface. An escape space (S2) continuous with the accommodation space (S1) is provided between the housing and the cover, the escape space (S2) being located closer to the first side than the inclined surface (63) is.