Forged Crankshaft Stability During Coining Process
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Solution Overview
Problem
Conventional methods for manufacturing forged crankshafts with recessed arms face challenges in maintaining stability during the coining process due to excess protruding portions, leading to potential twisting and instability, which complicates the application of desired forces for shaping.
Innovation Solution
A forged crankshaft manufacturing apparatus and method that includes a retaining device to maintain the forged blank in a specified posture and a moving device to ensure the excess portions are bent or crashed uniformly, preventing twisting and ensuring stable deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If excess portions are left on the forged blank for weight reduction, then the crankshaft weight is reduced, but the stability during coining process deteriorates causing twisting
Solution Approach 1:
The excess portions are removed before the coining process to prevent instability and twisting during shaping. This preliminary removal of material that would cause problems during subsequent operations resolves the contradiction by enabling both weight reduction and process stability.
Solution Approach 2:
The manufacturing process is divided into distinct stages: trimming to remove excess portions, followed by coining for final shaping. This segmentation allows each operation to be optimized independently, with trimming preparing the blank for stable coining while still achieving weight reduction.
2Shape
If force is applied to bend or crash excess portions, then the desired shape is achieved, but twisting occurs due to instability
Solution Approach 1:
Excess portions are removed before the coining operation, eliminating the source of instability that would cause twisting when force is applied. This preliminary preparation ensures that subsequent shaping forces produce accurate results without distortion.
Solution Approach 2:
The excess portions that would cause harm (instability and twisting) are converted into a benefit by removing them in advance, allowing the coining process to proceed with stable, precise force application that achieves the desired shape accurately.
3Weight of moving object
If coining is performed on forged blank with excess portions, then weight reduction is achieved, but the process complexity increases due to instability control
Solution Approach 1:
The process is segmented into trimming (removing excess portions) followed by coining (final shaping). This separation simplifies each individual operation by eliminating the need to control instability during coining, reducing overall process complexity while maintaining weight reduction benefits.
Solution Approach 2:
The trimming operation is performed as a preliminary step to remove excess portions before coining. This preliminary action eliminates the need for complex instability control mechanisms during the coining process, simplifying the overall manufacturing process while achieving weight reduction.
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
The apparatus and method enable stable processing of excess portions, maintaining the crankshaft's stability and accuracy in shape formation, thereby preventing twisting and ensuring a correctly formed crankshaft with reduced weight and assured stiffness.
Implementation Method 1
a first die and a second die paired with each other, which bend or crash the excess portion
Implementation Method 2
a retaining device that retains at least one of the rough journals or at least one of the rough pins of the forged blank such that a rough pin decentering direction in which the rough pins are decentered from the rough journals is perpendicular to a reducing direction
Implementation Method 3
a moving device that supports the retaining device such that the retaining device is movable along the reducing direction
Data Source
AI summary
A forged crankshaft manufacturing apparatus processes a forged blank with no flash. The forged blank includes at least one rough crank arm having an excess portion protruding from an outer periphery of a side portion thereof. The manufacturing apparatus includes a first die and a second die paired with each other, a retaining device, and a moving device. The first die and the second die bend or crash the excess portion. The retaining device retains at least one of the rough journals or at least one of the rough pins such that a rough pin decentering direction is perpendicular to a reducing direction in which the first die and the second die apply force for reduction. The moving device supports the retaining device such that the retaining device is movable in the reducing direction.