Dual-Pump Servo Hydraulic Press for Low-Speed Forming

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Solution Overview

Problem

Servo hydraulic presses face damage when operated at low speeds due to the stress on motors and pumps, necessitating a solution to enable low-speed operation without component damage.

Innovation Solution

A servo hydraulic press design featuring two servo motors and pumps operating in opposite directions, with the ability to adjust speed and direction to maintain component longevity, and a closed-loop fluid supply system with internal valves for pressure regulation, allowing for safe low-speed operation and efficient pressure management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the servo hydraulic press operates at low speed, then energy consumption is reduced and precision is improved, but the motors and pumps suffer damage due to low-speed operation stress

Engineering Contradiction:
Improveoperating speedVSAvoidcomponent lifespan
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The hydraulic press system is segmented into two independent pump-motor units (first pump 3a with motor 4a, second pump 3b with motor 4b) that can operate independently or in combination. This segmentation allows the system to distribute the low-speed operation stress across multiple components rather than overloading a single motor-pump unit, thereby maintaining component reliability during low-speed operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the operational parameters by operating the two pump-motor units in opposite directions with different speed parameters. The first motor 4a and second motor 4b can rotate in opposite directions, allowing one motor to operate at higher speed while the other compensates, thereby maintaining overall system pressure while protecting individual components from low-speed damage.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If pressure regulation is implemented during low-speed operation, then system safety is improved, but device complexity increases

Engineering Contradiction:
Improvesystem safetyVSAvoidpressure regulation system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pressure regulation function is merged with the existing dual pump-motor system by utilizing the opposite-direction operation capability of motors 4a and 4b. The system combines the pressure generation function with the pressure regulation function in a single integrated mechanism, eliminating the need for separate pressure regulation devices and reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The dual pump-motor system provides self-regulation of pressure through the opposite-direction operation of motors 4a and 4b. The system automatically balances pressure by adjusting the relative speeds and directions of the two motors, eliminating the need for external pressure regulation mechanisms and reducing device complexity.

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

Enables the servo hydraulic press to operate at low speeds without damaging the motors and pumps, extending their lifespan and reducing the need for pressure regulation during low-speed operations, while ensuring sufficient pressure and safety through controlled fluid flow.

Implementation Method 1

a first pump (3a) driven by a first servo motor (4a) and a second pump (3b) driven by a second servo motor (4b), for supplying pressurized fluid to the hydraulic cylinder (6, 7)

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

The first servo motor (4a) and its associated first pump (3a) are configured to operate in an opposite direction to the second servo motor (4b) and its associated second pump (3b), providing a reduced total pressure

Methodology Applied
Scientific EffectHydraulic pressure regulation: Hydraulic Press

Implementation Method 3

In the internal valve the pressurized fluid is transported between an upper chamber and a lower chamber depending on the working status of the cylinder

Methodology Applied
Scientific EffectHydraulic fluid transport: Hydraulic Press

Data Source

PatentEP3311997B1Servo hydraulic press
Publication Date: 2024.09.11 AUTOMATION PRESS & TOOLING AP&T AB
  • EP3311997B1 patent drawingFigure 1
  • EP3311997B1 patent drawingFigure 2a~2b

AI summary

The present invention relates to a servo hydraulic press for sheet metal forming. The press comprises a hydraulic cylinder (6,7), at least two servo motors (4a,4b) and at least two pumps (3a,3b) for supplying pressurized fluid to the hydraulic cylinder (6,7), where each servo motor (4a,4b) drives at least one pump (3a,3b). The servo motors are operable at variable speed, and the first servo motor (4a) and first pump (3a) are operable in an opposite direction to the second servo motor (4b) and the second pump(3b). With this arrangement, the servo hydraulic press may be operated at low speed without causing damage to the pumps or motors.