Steering Column Screw Structure for Rattle-Free Adjustment
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Solution Overview
Problem
Conventional steering column devices experience rattling due to a gap between the male and female screw shaft members, leading to a complex structure and high manufacturing costs.
Innovation Solution
A steering column device with a female screw member featuring a fragile section and a screw engaging section, where the fragile section extends when an adjust member is screwed in, expanding the thread pitch and pressing the screw threads together to suppress rattling, using a simple configuration with minimal additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gap is provided in the screwing portion of the male and female screw shaft members, then sliding is enabled, but rattling occurs in the steering shaft
Solution Approach 1:
The female screw member is divided into three distinct sections: a main body section, a fragile section with reduced rigidity, and a screw engaging section. This segmentation allows the fragile section to extend axially when pulled, expanding the thread pitch and pressing the screw threads together to eliminate gaps and suppress rattling while maintaining sliding capability.
Solution Approach 2:
The rigidity parameter of the female screw member is changed by creating a fragile section with lower rigidity compared to the main body section. This parameter change enables the fragile section to extend axially under load, which expands the thread pitch and presses the screw threads together, eliminating gaps and preventing rattling.
2Reliability
If two nuts, a wedge member, and additional screw members are added to suppress rattling, then rattling is reduced, but the number of components increases and structure becomes complicated
Solution Approach 1:
The fragile section and screw engaging section are integrally formed as part of the female screw member, merging multiple functional elements into a single component. This integration eliminates the need for separate nuts, wedge members, and screw fasteners, reducing the total number of components while maintaining rattling suppression functionality.
Solution Approach 2:
The fragile section automatically extends axially when pulled by the adjust member, self-adjusting the thread pitch to press the screw threads together and suppress rattling without requiring additional active components or complex control mechanisms.
3Stability of the object's composition
If multiple additional components are added to prevent the wedge member from coming off, then component retention is improved, but manufacturing cost increases
Solution Approach 1:
The screw engaging section is integrally formed with the main body section of the female screw member, merging the retention function into the existing structure. This eliminates the need for separate screw fasteners and double nuts, reducing manufacturing complexity and cost while maintaining component retention stability.
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
Effectively suppresses rattling between the male and female screw shaft members by expanding the thread pitch, ensuring a secure connection while reducing the number of components and manufacturing costs.
Implementation Method 1
A rigidity of the fragile section in the axial direction of the male screw shaft member is lower than rigidity of the main body section in the axial direction of the male screw shaft member so that the fragile section is extendable in the axial direction of the male screw shaft member when being pulled in the axial direction of the male screw shaft member
Data Source
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AI summary
A steering column device (1) includes a male screw shaft member (25) rotatably supported by an outer column (5) and a female screw member (27) provided in a link member (39), the male screw shaft member (25) being screwed to the female screw member (27). The female screw member (27) and the male screw shaft member (25) are moved relative to each other by rotation of the male screw shaft member (25), causing the link member (39) to swing relative to the outer column (5). The female screw member (27) includes a main body section (29) supported by the link member (39), a fragile section (31) provided on one side of the main body section (29), and a screw engaging section (33) provided on the opposite side of the fragile section (31) from the main body section (29). In a state where an adjust nut (73) is screwed to the screw engaging section (33), a distal end portion (73a1) of the adjust nut (73) comes into contact with the main body section (29) and extends the fragile section (31) in the axial direction of the male screw shaft member (25).