Hydraulic Press Piston Control Device Pressure Preload Damping

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Solution Overview

Problem

Control devices for piston-cylinder arrangements in hydraulic presses face durability issues due to mechanical damage from pressure peaks and vibration excitations, leading to premature component failure and increased maintenance costs.

Innovation Solution

A control device that switches between a pump system and a storage system for hydraulic fluid supply, using a throttle valve to manage pressure and automatically release connections to prevent pressure peaks, while a prestressing device generates a pressure preload to increase the natural frequency of the hydraulic axis, damping pressure excitations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional control device with valve arrangement is used for piston-cylinder arrangement, then the basic control function is achieved, but pressure peaks and vibration excitations cause mechanical damage and reduced durability

Engineering Contradiction:
Improvedurability of control deviceVSAvoidpressure peaks and vibration excitations
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control device prepares the hydraulic system in advance by establishing a pressure preload in the first subchamber before piston movement occurs. This preliminary pressure state prevents sudden pressure peaks during piston acceleration, thereby reducing mechanical damage and improving durability of the control device components.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention introduces a cushioning effect by maintaining a predetermined pressure preload in the hydraulic fluid of the first subchamber. This pre-established pressure buffer absorbs and dampens pressure excitations and vibration impulses that would otherwise cause mechanical damage to valves and line systems, thereby protecting the control device.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Stress or pressure

If the valve arrangement opens to allow fluid outflow when pressure exceeds control value, then pressure control is achieved, but this creates pressure peaks that damage components

Engineering Contradiction:
Improvepressure controlVSAvoidcomponent durability
Core Design Contradiction:
Stress or pressureVSStrength

Solution Approach 1:

The system pre-establishes a pressure preload in the first subchamber that is maintained below the valve opening pressure control value. This preliminary pressure state ensures that when the piston moves, the pressure increases gradually from this preload level rather than from zero, preventing sudden pressure peaks that would trigger immediate valve opening and cause mechanical damage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the pressure parameter profile by maintaining a continuous pressure preload in the first subchamber rather than allowing pressure to fluctuate from zero to high values. This parameter modification smooths the pressure curve during piston movement, preventing the sharp pressure peaks that cause valve damage and extending component life.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If the connection to the storage system is automatically released when pressure exceeds threshold, then pressure peaks are prevented, but this requires complex sensors and control commands

Engineering Contradiction:
Improvepressure peak preventionVSAvoidsensors and control commands
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The control device uses the existing pressure conditions in the hydraulic system to automatically control the connection to the storage system. The valve arrangement responds to pressure changes without requiring external sensors or control commands, as the pressure differential itself drives the automatic connection and disconnection of the storage system, simplifying the control architecture.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention uses the pressure differential between the first subchamber and the storage system as an intermediary mechanism to control the connection state. This pressure-based intermediary automatically manages the storage system connection without requiring additional sensors or electronic control, thereby preventing pressure peaks while maintaining simple device architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If a prestressing device generates pressure preload independently of load, then natural frequency increases and pressure excitations are damped, but this adds device complexity

Engineering Contradiction:
Improvepressure excitation dampingVSAvoidprestressing device
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The control device achieves pressure preload generation using the existing hydraulic pump and valve arrangement already present in the system. The pump supplies hydraulic fluid to create the pressure preload in the first subchamber, and the valve arrangement controls the pressure level. This multi-functional use of existing components generates pressure preload without adding separate prestressing device hardware, thereby damping pressure excitations while maintaining simple device architecture.

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

Solution Approach 2:

The existing hydraulic system components (pump, valve arrangement, hydraulic fluid) are made to serve the additional function of generating and maintaining pressure preload. The pump continuously supplies fluid to maintain the pressure preload, and the valve arrangement automatically regulates it, allowing the system to self-generate the necessary pressure conditions without external prestressing equipment.

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

The solution enhances the durability of the control device and piston-cylinder arrangement by reducing pressure peaks and mechanical loads, allowing for smoother operation and reduced maintenance costs by maintaining the connection to the accumulator system without sensors or control commands, and ensuring precise control of the piston movement.

Implementation Method 1

the valve arrangement connected to a first partial chamber has the known function, the dead weight of, for example, the pistons of such piston-cylinder arrangements coupled matrix to compensate. For this purpose, a pressure control value is set on the valve arrangement, which is at least as high as the pressure in a fluid contained in the first subchamber

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

a prestressing device is coupled to the valve arrangement and the first partial chamber and serves to prepare for damping a pressure load in the fluid caused by a movement of the piston caused by a load acting on the piston in the direction of the first partial chamber

Methodology Applied
Scientific EffectPressure preload: Pressure Increase

Implementation Method 3

a piston-cylinder arrangement having a cylinder and a piston which is at least partially accommodated in the cylinder and divides the cylinder interior into two sub-chambers along the cylinder axis

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP1924773B1Control apparatus and control method for a piston/cylinder arrangement
Publication Date: 2018.12.05 LAEIS GMBH
  • EP1924773B1 patent drawingFigure 1
  • EP1924773B1 patent drawingFigure 2a
  • EP1924773B1 patent drawingFigure 2b

AI summary

Control apparatus for a piston/cylinder arrangement, wherein the piston/cylinder arrangement has a cylinder and a piston which is accommodated at least partially in the cylinder and divides the cylinder interior along the cylinder axis into two part spaces, having a valve arrangement which is connected to a first part space and assumes a closed position which prevents a fluid which is held in the first part space from flowing out of this part space if the pressure in the fluid is smaller than a pressure control value which is set on the valve arrangement, and which opens into an opening position which makes this outflow possible if the pressure in the fluid is correspondingly greater than the pressure control value which has been set, having a priming device which is coupled to the valve arrangement and the first part space, serves to prepare for the damping of a pressure increase in the fluid which is brought about by a movement of the piston which is caused by a load which acts on the piston in the direction of the first part space, and by means of which a pressure increase can be generated in the fluid to a predefined pressure priming value independently of the load, and a method for controlling a piston/cylinder arrangement of this type and the use of a control apparatus of this type for a piston/cylinder arrangement of a hydraulic press.