Crankshaft Counterweight Shoulder Angle Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing crankshaft counterweights are difficult to make lightweight while maintaining sufficient filling during the forging process, which affects their balance and functionality.
Innovation Solution
The counterweight design includes an arm connecting the crank journal and crank pin, a neck extending from the junction, and a fan-shaped weight with shoulders tilted at an angle between 15° and 22.5° from the horizontal direction, optimizing the ratio of neck width to radius to achieve a lightweight and balanced counterweight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the counterweight shape is adjusted to make the crankshaft lightweight, then the weight of the crankshaft is reduced, but the counterweight portion becomes less filled in the forging process
Solution Approach 1:
The patent applies parameter changes by optimizing the shoulder angle parameter to a specific range (15° to 22.5°) and the neck width-to-radius ratio (h/R) to (0.44 to 0.49). These parameter adjustments enable the counterweight to achieve both lightweight design and sufficient filling during the forging process, resolving the technical contradiction between reducing crankshaft weight and ensuring proper material filling.
2Weight of moving object
If the angle formed by the shoulder and horizontal direction is made smaller, then the counterweight can be made lightweight, but the filling in the forging process becomes insufficient
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal parameter range for the shoulder angle (15° to 22.5°) and the neck width-to-radius ratio (0.44 to 0.49). Within this parameter range, the counterweight achieves both reduced weight and sufficient filling during forging, eliminating the need to choose between lightweight design and manufacturing ease.
3Manufacturing precision
If the angle formed by the shoulder and horizontal direction is made larger, then the counterweight is filled more sufficiently in the forging process, but the crankshaft weight increases
Solution Approach 1:
The patent applies parameter changes by defining a precise optimal range for the shoulder angle (15° to 22.5°) and the neck width-to-radius ratio (0.44 to 0.49). These parameter specifications ensure that the counterweight achieves sufficient filling during forging while maintaining lightweight characteristics, thus resolving the contradiction between manufacturing quality and weight reduction.
Data Source
AI summary
A counterweight forms a crankshaft of an engine, and includes: an arm connecting a crank journal and crank pin of the crankshaft; a neck extending from a first connection face of the arm in a direction opposite to the crank pin; and a substantially fan-shaped weight continuous with a portion of the neck opposite to the crank journal. The weight has left and right shoulders continuous with the neck, and each of the shoulders is tilted to be away from the neck at an angle with respect to a horizontal line orthogonal to a crankshaft center when viewed along the crankshaft center, the angle being 15° or more and 22.5° or less.