Composite Hydraulic Hammer Piston Sleeve for Lower Weight

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Solution Overview

Problem

Conventional piston sleeves for hydraulic hammers are heavy and costly to fabricate, limiting their application to smaller machines and requiring cumbersome and expensive manufacturing processes.

Innovation Solution

A composite sleeve structure composed of a guide layer, an energizer layer, and a support layer, made from materials like plastic and rubber, with a porous honeycomb pattern to reduce weight and facilitate fluid flow, and fabricated using 3-D printing for reduced complexity and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metallic piston sleeve with iron liner is used, then the sleeve provides sufficient strength and durability, but the weight becomes considerable and limits application to smaller machines

Engineering Contradiction:
Improvesleeve strengthVSAvoidsleeve weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining a metallic outer sleeve with a polymer liner, creating a hybrid structure that leverages the strength of metal and the lightweight properties of polymer. This composite approach reduces overall weight while maintaining structural integrity and functional performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes a thin polymer liner as a flexible shell that lines the metallic sleeve. This thin film provides necessary functional properties (such as sealing and fluid transport) while adding minimal weight, thereby reducing the overall sleeve weight without compromising strength.

Inventive Principle:
Principle #30Flexible shells and thin films

2Manufacturing precision

If conventional machining processes are used to create fluid passages in the sleeve, then the passages can be precisely formed, but the fabrication becomes cumbersome and expensive

Engineering Contradiction:
Improvepassage precisionVSAvoidfabrication ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces traditional mechanical machining processes with a molding process for creating fluid passages. By forming passages directly during the liner manufacturing process, the need for subsequent machining operations is eliminated, simplifying fabrication and reducing costs while maintaining precise passage geometry.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent merges the formation of the polymer liner and the fluid passages into a single manufacturing step. The passages are integrated directly into the liner structure during molding, combining what would traditionally be separate manufacturing operations into one unified process, thereby reducing fabrication complexity and expense.

Inventive Principle:
Principle #5Merging (Combining)

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 composite sleeve design reduces weight, enhances fluid sealing, and simplifies manufacturing, enabling more efficient and productive hydraulic hammer operations, particularly suitable for smaller machines.

Implementation Method 1

a porous honeycomb pattern to reduce weight and facilitate fluid flow

Methodology Applied
Scientific EffectPorosity: Porosity

Data Source

PatentEP3285968B1Piston sleeve for hydraulic hammer
Publication Date: 2021.11.10 CATERPILLAR INC
  • EP3285968B1 patent drawingFigure 1
  • EP3285968B1 patent drawingFigure 2
  • EP3285968B1 patent drawingFigure 3

AI summary

A sleeve (44) is disclosed for use with a piston (46) of a hydraulic hammer (12). The sleeve may have a generally cylindrical body with a top end (28) and a bottom end (26), and a central bore (94) passing axially from the top end of the generally cylindrical body to the bottom end. The generally cylindrical body may be a composite structure including a guide layer (68) forming an inner annular surface of the central bore, an energizer layer (70) located radially outward of the guide layer and being bonded to the guide layer, and a support layer (72) bonded to the energizer layer. The support layer may form an outer surface of the generally cylindrical body.