Steering Column Outer Jacket Segmentation
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Solution Overview
Problem
Conventional steering column devices have high manufacturing costs due to the need for core drafting and machining, which restricts size and shape, and can lead to surface roughness and operational issues like slide noise and wear during telescopic adjustment.
Innovation Solution
A steering column device comprising a cylindrical inner and outer jacket, where the outer jacket is divided into molded half members allowing for constant diameter and reduced machining, with grooves for weight reduction and locking, eliminating the need for core drafting and separate locking structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the outer column is cast with a draft on the inner circumferential surface, then the core can be pulled out during casting, but the manufacturing cost increases and the inner diameter cannot remain constant
Solution Approach 1:
The outer column is divided into a first half member and a second half member that are molded separately and then assembled. This segmentation allows each half to be molded without requiring draft angles on the inner circumferential surface, maintaining constant inner diameter while enabling core removal through the assembly process rather than through draft angles on the inner surface.
2Manufacturing precision
If the inner circumferential surface is machined after casting to achieve constant inner diameter, then the telescopic adjustment clearance is secured, but the manufacturing cost increases and the outer column size and shape are restricted
Solution Approach 1:
By dividing the outer column into two half members that are molded separately and assembled, the design achieves constant inner diameter without requiring post-casting machining. This segmentation approach removes restrictions on outer column size, shape, and bearing dimensions while maintaining the required clearance for telescopic adjustment.
Solution Approach 2:
Instead of achieving constant inner diameter through machining after casting, the invention inverts the approach by molding the half members with constant inner diameter from the beginning and assembling them to form the complete outer column. This eliminates the need for restrictive machining operations.
3Manufacturing precision
If the inner circumferential surface is cut by machining, then the inner diameter is made constant, but machining traces and surface roughness deteriorate, causing slide noise and wear
Solution Approach 1:
The outer column is segmented into two half members that are molded separately and assembled. This approach allows the inner circumferential surface to maintain constant diameter without machining, preventing machining traces and surface roughness deterioration that would cause slide noise and wear during telescopic adjustment.
4Device complexity
If the outer column is cast as a single piece, then the structure is simple, but the size and shape are restricted by the need for draft angles
Solution Approach 1:
The outer column is divided into a first half member and a second half member that are molded separately and assembled. This segmentation provides design flexibility for size, shape, and bearing dimensions while maintaining relatively simple structure through the assembly of two molded parts, overcoming the limitations of single-piece casting.
Data Source
AI summary
A steering column device includes a cylindrical inner jacket; a cylindrical outer jacket in which the inner jacket is slidably inserted; and a steering shaft rotatably supported in the inner jacket and the outer jacket. The outer jacket is divided into a molded first half member and a molded second half member at a plane including an axis of the outer jacket. According to this steering column device, in molding the outer jacket, it is not necessary to set a draft for a core along the axial direction on the inner circumferential surface of the outer jacket.