Workpiece Enlargement via Compressive Stress and Alternating Shear
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Solution Overview
Problem
The existing method for enlarging a shaft member by applying rotational bending stress results in buckling and instability when the bending angle exceeds a certain limit, due to insufficient compressive force, leading to difficulties in forming a stable enlarged portion without energy dissipation and fatigue damage.
Innovation Solution
An enlarging method that applies compressive stress equal to or greater than the initial yield strength, combined with alternating energy in a transverse direction to deform the workpiece within its elastic limit, effectively decomposing internal energy and inducing plastic flow to form a desired enlarged portion without buckling or fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotational bending stress is applied to enlarge the shaft member, then the enlarging process can proceed with reduced machining time and energy, but the shaft member may buckle when the bending angle exceeds a certain limit due to insufficient compressive force
Solution Approach 1:
The compressive force is applied in advance to the shaft member before rotational bending stress is applied. This preliminary compression pre-compresses the material, increasing its resistance to buckling during the subsequent enlarging process. The compressive force is maintained throughout the enlarging operation to ensure stability.
Solution Approach 2:
The compressive force parameter is adjusted to be equal to or greater than the initial yield strength of the shaft member, which is a significant increase from conventional methods. This parameter change ensures that the material remains in a compressed state that prevents buckling while allowing controlled plastic deformation during enlarging.
2Reliability
If compressive force is increased to prevent buckling, then the stability of the enlarged portion improves, but the working load and energy consumption increase
Solution Approach 1:
The compressive force is applied continuously throughout the entire enlarging process, from initial contact to completion of the enlarged portion. This continuous compression maintains the material in a stable state, preventing buckling and energy dissipation, while the rotational bending stress is applied in a controlled manner to achieve gradual plastic deformation.
Solution Approach 2:
The working method combines static compressive force with dynamic rotational bending stress. The compressive force remains constant and continuous, while the bending stress is applied dynamically through rotation, creating an efficient combination that maintains stability without requiring excessive energy input.
3Productivity
If the bending angle is increased to accelerate the enlarging process, then the productivity improves, but the shaft member deviates from the original axis and buckles
Solution Approach 1:
The continuous compressive force acts as a counteracting force that prevents the shaft member from deviating from its original axis during the enlarging process. This compressive 'counterweight' balances the lateral forces generated by rotational bending, maintaining axial alignment while allowing the enlarging process to proceed efficiently.
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 method stabilizes the enlargement process, reduces energy consumption, and prevents thermal alterations, enabling reliable formation of enlarged portions with improved workability and reduced risk of blue brittleness.
Implementation Method 1
applying compression energy that produces, in the workpiece, compressive stress equal to or greater than an initial yield strength to increase internal energy of the workpiece
Implementation Method 2
applying, in a transverse direction intersecting the axis, alternating energy that deforms the workpiece within an elastic limit thereof
Implementation Method 3
the alternating energy plastically deforms and enlarges the enlargement intended area
Implementation Method 4
the repetitive stress is sufficient to effectively decompose (or dissipate) the internal energy of the workpiece that is increased as a result of the application of the compression energy
Data Source
Figure 1
Figure 2(A)~2(B)
Figure 3(A)~3(C)
AI summary
A workpiece enlarging method is provided, by which an enlarged portion can stably be formed on a portion of a workpiece such as a shaft member, and a drive force required to form the enlarged portion can be reduced. The workpiece enlarging method forms the enlarged portion on the workpiece (W) by applying, with respect to the workpiece (W), alternating shear energy in a transverse direction thereof so as to suppress deformation of the workpiece (W) within an elastic limit while applying compression energy that produces compressive stress equal to or greater than an initial yield strength to increase internal energy of the workpiece (W), thereby decomposing (or dissipating) a portion of the increased internal energy by the alternating shear energy and deforming and enlarging the enlargement intended area of the workpiece (W) with the assistance of the decomposed (or dissipated) energy obtained by the decomposition (or dissipation).