Hydraulic Drum Cylinder Angular Offset Noise Reduction
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Solution Overview
Problem
Hydraulic machines with pistons in cylinders generate significant noise due to pressure shocks, particularly in hybrid vehicles where high-speed rotation leads to unpleasant siren-like noise emissions, which are not adequately reduced by existing offset adjustments.
Innovation Solution
A hydraulic machine with a drum and cylinders featuring angular offsets for the openings of the cylinders, optimized using a 'Scrambler' method that applies a pseudo random binary order through additive calculation, distributing offsets across a range to maximize noise reduction and align the noise signature with combustion engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If small angular offsets are applied to cylinder openings, then noise emissions are partially reduced, but the reduction is insufficient for high-speed hybrid vehicle applications
Solution Approach 1:
The patent applies parameter changes by systematically varying the angular offsets of cylinder openings across multiple parameters: offset magnitude (from 0 to maximum), offset direction (ahead or behind cylinder axis), and distribution pattern (regular or irregular). This multi-parameter optimization achieves sufficient noise reduction for high-speed hybrid vehicle applications where small offsets alone are inadequate.
2Object-affected harmful factors
If angular offsets are applied to cylinder openings, then pressure shock frequency is reduced, but the complexity of opening configuration increases
Solution Approach 1:
The patent applies local quality by assigning different angular offset characteristics to different cylinder openings based on their specific positions and functions. Each opening can have its own optimized offset parameters rather than applying a uniform offset to all cylinders, allowing tailored noise reduction for each cylinder-manifold interaction while maintaining overall system coherence.
3Object-affected harmful factors
If large angular offsets are applied to cylinder openings, then noise reduction is maximized, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies partial or excessive action by implementing angular offsets that may exceed traditional design limits to achieve maximum noise reduction. The configuration allows for irregular and asymmetric offsets that go beyond conventional symmetric patterns, prioritizing noise reduction performance while accepting increased manufacturing complexity as a necessary trade-off.
Data Source
AI summary
A hydraulic machine comprising a drum (12) rotated by an input shaft, comprising cylinders (14) distributed around the shaft, each receiving a piston that slides on the basis of the rotation of the shaft, each cylinder opening at an opening (30) on a transverse face of the drum bearing on a plate having inlet and outlet manifolds, the openings (30) comprising, relative to the cylinders (14) of same, angular offsets comprised within a total offset range, characterized in that the offsets of the openings (30) are disposed at one end or the other of this offset range.