Hydraulic Hammering Device Piston Acceleration

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional hydraulic hammering devices face limitations in increasing hammering power by shortening piston stroke without reducing hammering energy, as shorter strokes decrease piston speed and efficiency due to increased leakage and altered hydraulic circuit arrangements.

Innovation Solution

A hydraulic hammering device with an urging unit positioned behind the piston to contact and accelerate it during the retreat stroke, allowing earlier contact than the switching-valve mechanism's braking point, thus shortening the retreat stroke and maintaining piston speed without altering the hydraulic circuit arrangement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the piston stroke is shortened to increase hammering frequency, then productivity is improved, but piston speed decreases and hammering energy is reduced

Engineering Contradiction:
Improvehammering frequencyVSAvoidpiston speed
Core Design Contradiction:
ProductivityVSSpeed

Solution Approach 1:

The urging unit applies force to the piston in advance during the retreat stroke, accelerating the piston before the switching-valve mechanism acts. This preliminary acceleration ensures that the piston maintains sufficient speed even when the overall stroke is shortened, thereby resolving the contradiction between increased hammering frequency and maintained piston speed

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the piston stroke is shortened to increase hammering frequency, then productivity is improved, but hammering energy is reduced

Engineering Contradiction:
Improvehammering frequencyVSAvoidhammering energy
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The urging unit performs preliminary acceleration of the piston during the retreat stroke, storing kinetic energy that is converted to hammering energy at the impact point. This allows the system to maintain hammering energy while operating with shorter strokes and higher frequency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the timing parameter of piston acceleration by introducing the urging unit that acts during the retreat stroke rather than only during the advance stroke. This parameter change enables the piston to achieve necessary speed and energy levels with shorter overall stroke length

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the hydraulic circuit arrangement is altered to shorten piston stroke, then productivity is improved, but device complexity increases

Engineering Contradiction:
Improvehammering frequencyVSAvoidhydraulic circuit arrangement
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The urging unit is integrated into the existing hydraulic circuit and serves multiple functions: it accelerates the piston during retreat, works in conjunction with the switching-valve mechanism, and can be controlled through the existing valve-control passage. This multi-functionality allows stroke shortening without proportionally increasing system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution enhances hammering power by shortening the piston stroke while maintaining hammering energy and preventing efficiency reduction, allowing flexible control of stroke shortening through the contact position and thrust ratio between the piston and urging unit.

Implementation Method 1

an urging unit disposed behind the piston and configured to come in contact with the piston during a piston retreat stroke to urge the piston forward

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

The switching-valve mechanism 130 is a known switching valve disposed in a suitable position inside or outside the cylinder 100P, and operates with the aid of pressurized oil supplied/discharged via a valve-control passage 122

Methodology Applied
Scientific EffectHydraulic pressure control: Pressure Increase

Data Source

PatentEP3569362B1Hydraulic hammering device
Publication Date: 2023.01.11 FURUKAWA ROCK DRILL
  • EP3569362B1 patent drawingFigure 1
  • EP3569362B1 patent drawingFigure 2A~2F
  • EP3569362B1 patent drawingFigure 3~4

AI summary

To improve hammering power by shortening a piston stroke, without changing hydraulic circuit arrangement and while keeping its hammering energy. A hydraulic hammering device includes a piston front chamber (110) and a piston rear chamber (111) 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) disposed behind the piston and configured to come in contact with the piston during a retreat stroke thereof to urge the piston (200) forward, in which a timing where the acceleration piston (410) itself starts to come in contact with the piston is set to be earlier than a timing where the piston (200) is braked by the switching-valve mechanism (130).