Crankshaft Counterweight With Monolithic Cavity And High-Density Insert
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Solution Overview
Problem
Existing crankshafts in reciprocating internal combustion engines face challenges in achieving high-density vibration dampening without the risks of contamination and material loss, particularly with materials like tungsten being costly and lead being toxic, while conventional solutions result in complex structures.
Innovation Solution
A monolithic counterweight body with a single opening for a high-density insert, cast into a cavity, which is sealed to prevent contamination and secured by centrifugal forces, allowing for the use of materials like lead or silver with reduced risk of loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If tungsten inserts are used in conventional counterweight, then high density is achieved, but material cost increases significantly
Solution Approach 1:
The patent changes the material parameter from tungsten to lead, which has lower density but significantly lower cost. This parameter change resolves the contradiction by accepting a trade-off between density and material cost, making the counterweight more economically viable while still achieving adequate vibration dampening properties
Solution Approach 2:
The patent employs lead, a cheaper alternative to tungsten, to create the counterweight insert. This principle is applied by substituting expensive materials with more economical ones that can still fulfill the functional requirements, thereby reducing manufacturing costs while maintaining sufficient performance
2Reliability
If lead is used in counterweight inserts, then vibration dampening characteristics improve, but toxicity risk increases
Solution Approach 1:
The patent introduces a metallic coating as an intermediary layer between the lead insert and the external environment. This coating acts as a barrier that prevents direct contact between toxic lead and surrounding components, thereby maintaining the vibration dampening benefits of lead while eliminating the toxicity hazard
Solution Approach 2:
The patent converts the harmful toxicity of lead into a beneficial solution by using the coating to contain the lead. The very property that makes lead harmful (its chemical reactivity and toxicity) is neutralized by the coating, allowing the beneficial vibration dampening characteristics to be utilized without the harmful effects
3Reliability
If separate counterweight attached to crankshaft are provided, then balance weight distribution is achieved, but device complexity increases
Solution Approach 1:
The patent merges the counterweight insert with the crankshaft body by casting the insert directly into the crankshaft. This integration eliminates the need for separate attached counterweights, reducing assembly steps and structural complexity while maintaining the weight distribution balancing function
Solution Approach 2:
The patent creates a multi-functional counterweight structure where the insert serves both as a balancing mass and as an integrated part of the crankshaft. This universal design achieves weight distribution balance while simplifying the overall structure by combining multiple functions into a single component
4Reliability
If high-density inserts are surrounded by energy absorbing medium, then rotational vibrations are dampened, but structure complexity increases
Solution Approach 1:
The patent combines the vibration dampening function directly into the counterweight insert itself by using lead material. This eliminates the need for separate energy absorbing media surrounding the insert, simplifying the counterweight structure while maintaining rotational vibration dampening capabilities
Solution Approach 2:
The patent applies local quality by using lead material with inherent vibration dampening properties directly in the counterweight insert. This localized application of vibration dampening material eliminates the need for complex surrounding structures, achieving the same effect with simpler design
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 solution provides effective vibration dampening with reduced risk of contamination and material loss, enabling the use of high-density materials like lead and silver, while maintaining a simpler and more efficient counterweight structure.
Implementation Method 1
the positioning of the opening results in that centrifugal forces acting on the insert during operation of an associated engine ensure that the insert maintains its position within the cavity
Data Source
Figure 1
AI summary
The disclosure concerns a counterweight (2) for a crankshaft (1) of a reciprocating internal combustion piston engine with a high density insert (5). A crankshaft (1) equipped with such a counterweight, a reciprocating internal combustion piston engine provided with such crankshaft (1) and a method for manufacturing such a counterweight are also concerned. The disclosure is based on the idea of providing the body (3) of the counterweight (2) as a one-piece, monolithic structure defining a cavity (4), in which the insert (5) is housed. Particularly, the cavity (4) has a single opening (4a) towards a side (3a) at which the counterweight (2) is attachable to a crankshaft (1), through which the insert (5) is cast into the cavity (4).