Integrated Steering Shaft Forging for Deep-Hole Weight Reduction
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Solution Overview
Problem
The existing methods for manufacturing steering shafts are costly and inefficient, with increased production costs due to the use of multiple components and prolonged cutting times, which can lead to reduced yield and accuracy issues.
Innovation Solution
A method involving forging to form a spline shaft part, a stopper part, and an intermediate shaft part from a single material, where a hole is recessed axially and then drawn radially to reduce weight and processing time, while forming a deep hole by multiple forging steps to enhance torque transmission reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple shaft components are used and press-fitted together, then torque transmission reliability is improved, but production cost and device complexity increase
Solution Approach 1:
The patent combines multiple shaft components (first shaft, second shaft, intermediate shaft) into a single integrated shaft structure. This merging eliminates the need for press-fitting operations and reduces the number of components while maintaining torque transmission reliability through the continuous metallic structure.
2Weight of moving object
If deep hole cutting is performed on pillar-shaped material, then weight reduction is achieved, but production time increases and position accuracy decreases
Solution Approach 1:
The patent changes the manufacturing parameter from cutting to forging for creating the hollow structure. By forming the hollow shape through forging operations during the shaping process, the method achieves weight reduction without the time-consuming and accuracy-reducing deep hole cutting operations.
3Weight of moving object
If deep hole cutting is performed, then weight reduction is achieved, but manufacturing precision and yield decrease due to cutting chips
Solution Approach 1:
The patent changes the material removal method from cutting to forging. The hollow structure is formed by forging operations that shape the material without generating cutting chips, thereby maintaining hole position accuracy and improving manufacturing precision while achieving weight reduction.
4Reliability
If multiple shaft parts are welded together, then torque transmission reliability is improved, but production cost increases
Solution Approach 1:
The patent merges multiple shaft parts into a single integrated component manufactured through forging operations. This eliminates the need for welding processes and associated costs while maintaining structural integrity and torque transmission reliability through the continuous metallic grain structure.
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 approach reduces the weight and production costs of the steering shaft while improving torque transmission reliability by integrating the spline shaft, intermediate shaft, and stopper parts, minimizing cutting defects and increasing yield.
Implementation Method 1
a step of forming a hole part recessed in an axial direction from one end of pillar-shaped material by forging
Implementation Method 2
a step of pressing the material in which the hole part has been formed into a die to perform drawing in a radial direction
Data Source
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AI summary
To provide a method of manufacturing a shaft for a steering device, the shaft including a spline shaft part to be coupled with an input shaft, a stopper part to be coupled with an output shaft, and an intermediate shaft part that couples the spline shaft part with the stopper part. The method includes: a step of forming a hole part recessed in an axial direction from one end of a pillar-shaped material by forging; and a step of pressing the material in which the hole part has been formed into a die to perform drawing in a radial direction on a portion of the material at which the stopper part is formed and prolonging a length along the axial direction of the hole part at the same time by forging.