Hollow Piston Pin Dynamic Vibration Absorber
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Solution Overview
Problem
The existing engine piston and connecting rod structure experiences resonance during the combustion stroke, leading to increased noise, which is not effectively reduced by dynamic vibration absorbers without increasing noise during other strokes.
Innovation Solution
Incorporating at least one dynamic vibration absorber inside the piston pin with a hollow cross-section, featuring two absorbers with equal masses and different spring constants, positioned on both sides of the piston pin's central axis, to reduce resonance and noise across various strokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a dynamic vibration absorber is added to reduce resonance during combustion stroke, then noise during combustion stroke is reduced, but device complexity increases
Solution Approach 1:
The dynamic vibration absorber is nested inside the hollow piston pin, utilizing the existing internal space of the piston pin structure. This allows the vibration reduction function to be integrated without adding external components or increasing the overall piston size, thereby reducing device complexity while maintaining noise reduction effectiveness.
2Stability of the object's composition
If the piston pin is made hollow to accommodate vibration absorbers, then resonance reduction capability is improved, but strength of the piston pin deteriorates
Solution Approach 1:
The piston pin is constructed using a composite structure combining a hollow outer shell with internal vibration absorbers. The hollow shell maintains structural strength while the internal absorbers provide vibration reduction, creating a composite system that achieves both mechanical strength and vibration stability without compromising either function.
3Object-affected harmful factors
If two dynamic vibration absorbers with different spring constants are used, then resonance reduction effectiveness is improved, but manufacturing precision requirements increase
Solution Approach 1:
The system uses two vibration absorbers with different spring constants to target different frequency ranges, effectively broadening the resonance reduction bandwidth. By carefully selecting the spring constant parameters of the two absorbers, the system achieves superior vibration reduction while the parameter differentiation allows for tolerance compensation in manufacturing.
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 dynamic vibration absorbers effectively reduce resonance and noise during the combustion stroke while minimizing noise from vibrations during intake, compression, and exhaust strokes, without increasing the piston's size, by utilizing the space within the piston pin.
Implementation Method 1
at least one dynamic vibration absorber provided inside the piston pin to reduce resonance of the piston, the piston pin, and the small end part of the connecting rod in combination with respect to the large end part of the connecting rod during a combustion stroke
Implementation Method 2
A lubricating oil film is formed between the piston pin and the inner surface of a pin insertion hole of the connecting rod. The lubricating oil film corresponds to a spring that couples the piston pin and the small end part of the connecting rod together.
Data Source
AI summary
An engine piston structure includes: a piston (1); a connecting rod (10) having a small end part (10a) coupled to the piston (1), and having a large end part (10b) coupled to a crankshaft; a piston pin (2) through which the piston (1) and the small end part (10a) of the connecting rod (10) are coupled together and which has a hollow cross section; and at least one dynamic vibration absorber (20) provided inside the piston pin (2) to reduce resonance of the piston (1), the piston pin (2), and the small end part (10a) of the connecting rod (10) in combination with respect to the large end part (10b) of the connecting rod (10) during a combustion stroke.