Two-Stage Hydraulic Press Control for Smooth Force Switching

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Solution Overview

Problem

Existing hydraulic press systems suffer from inefficiencies in energy consumption due to pressure fluctuations and inadequate control systems, leading to wasteful energy usage and operational costs, and often result in pressure peaks and interruptions during piston speed changes.

Innovation Solution

A two-stage hydraulic press system with a first and second drive mode, utilizing interconnected pistons and servo-driven pumps, allows for smooth transitions between modes, enabling precise control over speed and force, and includes a flow control valve to manage fluid flow between chambers, reducing energy consumption and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a switching valve is used to change from a small piston area to a larger piston area at a given pressure, then the pressing force is increased, but pressure collapse and pressure peaks occur, interrupting piston speed

Engineering Contradiction:
Improvepressing forceVSAvoidpiston speed continuity
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The system dynamically switches between two drive modes (first hydraulic cylinder alone, or both hydraulic cylinders together) based on operational requirements. The control unit continuously monitors system state and transitions between configurations, allowing the pressing component to operate with different piston areas without abrupt pressure changes, thereby maintaining piston speed continuity while adjusting pressing force.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The hydraulic press system is divided into two independent hydraulic circuits, each with its own servo-driven pump and control valve. This segmentation allows independent control of each cylinder, enabling smooth transitions between single-cylinder and dual-cylinder operation modes, avoiding the pressure instability caused by traditional single-circuit switching valves.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If existing hydraulic press systems use traditional control systems, then the system structure is simple, but energy consumption increases due to pressure fluctuations and inadequate control

Engineering Contradiction:
Improvecontrol system structureVSAvoidenergy consumption
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The control unit implements closed-loop feedback control by continuously monitoring pressure, flow, and piston position from sensors and adjusting the servo-driven pumps and control valves accordingly. This feedback mechanism eliminates pressure fluctuations and optimizes energy consumption by ensuring the hydraulic system operates only with the necessary power, avoiding wasteful energy usage while maintaining precise control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes operational parameters by switching between different hydraulic circuit configurations (single cylinder or dual cylinder operation) and adjusting servo pump speeds dynamically. This parameter adjustment allows the system to optimize energy consumption for different pressing requirements while maintaining simple overall system structure through standardized hydraulic components.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the hydraulic press system switches between different piston areas, then versatility is improved, but pressure peaks and interruptions occur

Engineering Contradiction:
Improvepressing capabilityVSAvoidpressure stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system dynamically transitions between operational modes (first hydraulic cylinder only, or both cylinders engaged) based on the pressing requirements. The control unit manages these transitions smoothly by coordinating the servo-driven pumps and control valves, allowing the system to adapt its pressing capability while maintaining pressure stability and avoiding abrupt pressure peaks or interruptions.

Inventive Principle:
Principle #15Dynamics

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 system achieves precise and efficient material forming with reduced energy consumption by maintaining full speed control during mode transitions, minimizing idle time and ensuring accurate force application, thus enhancing versatility and operational efficiency.

Implementation Method 1

a first servo-driven pump configured to deliver a first fluid to the first hydraulic cylinder; a second servo-driven pump configured to deliver a second fluid to the second hydraulic cylinder

Methodology Applied
Scientific EffectServo-driven pump: Pump

Implementation Method 2

a first hydraulic cylinder comprising a first piston defining two chambers of the first hydraulic cylinder; a second hydraulic cylinder comprising a second piston defining two chambers of the second hydraulic cylinder

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP4656888A1Two-stage hydraulic press system and method for operating a two-stage hydraulic press system
Publication Date: 2025.12.03 AUTOMATION PRESS & TOOLING AP&T AB
  • EP4656888A1 patent drawingFigure 1
  • EP4656888A1 patent drawingFigure 1b
  • EP4656888A1 patent drawingFigure 2

AI summary

The present invention relates to a two-stage hydraulic press system (100) having a first drive mode and a second drive mode, the two-stage hydraulic press system (100) comprises: a movable pressing component (104); a first hydraulic cylinder (110) comprising a first piston (112); a second hydraulic cylinder (120) comprising a second piston (122) defining two chambers (124a, 124b) of the second hydraulic cylinder (120); a first servo-driven pump (130) configured to deliver a first fluid to the first hydraulic cylinder (110); a second servo-driven pump (140) configured to deliver a second fluid to the second hydraulic cylinder (120); and a flow control valve (150), connected to the chambers (124a, 124b) of the second hydraulic cylinder (120), configured to engage and disengage the second piston (122), wherein the first piston (112) and the second piston (122) are coaxially mechanically interconnected and configured to move in unison to induce a movement of the movable pressing component (104); wherein, in the first drive mode, the second piston (122) is configured to be disengaged and at least the first servo-driven pump (130) is configured to induce a movement of the movable pressing component (104) with a first speed; and wherein, in the second drive mode, the second piston (122) is configured to be engaged and at least the second servo-driven pump (140) is configured to induce a movement of the movable pressing component (104) with a second speed.