Hydraulic Hammering Device Acceleration Piston Stroke

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Solution Overview

Problem

Conventional hydraulic hammering devices face a trade-off between increasing hammering frequency and maintaining hammering power, as shortening the piston stroke to enhance frequency results in decreased piston speed and overall power output.

Innovation Solution

Incorporating an acceleration piston that comes into contact with the main piston during its retreat stroke, providing additional thrust through pressurized oil, which shortens the retreat stroke and accelerates the advancing operation, thereby improving power without reducing hammering energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the piston stroke is shortened to increase hammering frequency, then hammering frequency increases, but piston speed decreases and overall power output decreases

Engineering Contradiction:
Improvehammering frequencyVSAvoidpower output
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The piston stroke is segmented into two distinct phases: advance stroke and retreat stroke. The advance stroke maintains sufficient length to preserve hammering energy and power, while the retreat stroke is shortened through the urging means to increase hammering frequency. This segmentation allows each phase to be optimized independently, resolving the contradiction between frequency and power output.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The urging means is introduced to dynamically control the retreat stroke duration. By applying urging force during the retreat phase, the piston returns to its starting position more quickly, increasing the overall hammering frequency without compromising the advance stroke characteristics that determine power output.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the piston stroke is shortened to enhance hammering frequency, then hammering frequency increases, but the energy per stroke decreases

Engineering Contradiction:
Improvehammering frequencyVSAvoidenergy per stroke
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The stroke is divided into advance and retreat phases, with only the retreat phase being shortened. The advance stroke maintains its original length to preserve energy per stroke, while the retreat stroke duration is reduced to increase frequency. This selective segmentation resolves the contradiction between frequency and energy per stroke.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The urging means prepares the piston for the next advance stroke by accelerating the retreat phase. This preliminary action during the retreat stroke ensures the piston is ready to initiate the next power-generating advance stroke more quickly, increasing frequency without reducing the energy available in each advance stroke.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the urging means is added to shorten retreat stroke, then hammering frequency increases, but device complexity increases

Engineering Contradiction:
Improvehammering frequencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The urging means is merged with the existing hydraulic system by utilizing the same pressurized oil supply. The urging force is generated through the existing hydraulic pressure, eliminating the need for separate actuators or power sources. This integration minimizes additional complexity while achieving the desired frequency increase.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hydraulic system serves dual purposes: it provides pressure for the advance stroke through the pressure-receiving area difference and simultaneously provides urging force for the retreat stroke through the urging means. This self-service approach allows the existing system to enhance frequency without requiring external additions, thereby limiting complexity increase.

Inventive Principle:
Principle #25Self-service

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

This configuration allows for a shortened piston stroke that increases hammering power while maintaining energy, by transiently enlarging the pressure-receiving area during the retreat stroke to enhance braking force and accelerate the piston's advance phase.

Implementation Method 1

pressurized oil acting on the piston

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

braking force by pressurized oil acting on the piston

Methodology Applied
Scientific EffectBraking force: Friction

Implementation Method 3

additional thrust through pressurized oil

Methodology Applied
Scientific EffectHydraulic thrust: Pressure Increase

Implementation Method 4

accelerates the advancing operation

Methodology Applied
Scientific EffectAcceleration: Force

Data Source

PatentEP3323564B1Hydraulic hammering device
Publication Date: 2022.03.23 FURUKAWA ROCK DRILL
  • EP3323564B1 patent drawingFigure 1
  • EP3323564B1 patent drawingFigure 2A~2D
  • EP3323564B1 patent drawingFigure 3~4

AI summary

To improve hammering power by shortening a piston stroke, while keeping its hammering energy. The hydraulic hammering device including: a cylinder (100); a piston (200) slidingly fitted in the cylinder (100); a piston front chamber (110) and a piston rear chamber (111) which are defined between an outer circumferential surface of the piston (200) and an inner circumferential surface of the cylinder (100) and disposed separately from each other at front and rear, respectively, in an axial direction; a switching-valve mechanism (130) driving the piston by switching at least one of the piston front chamber (110) and the piston rear chamber (111) into communication with at least one of a high pressure circuit (101) and a low pressure circuit (102); and an acceleration piston (410) as an urging means, which is disposed behind the piston (200) and comes in contact with the piston (200) during a retreat stroke of the piston (200), to urge the piston (200) forward in cooperation with braking force by pressurized oil acting on the piston (200).