Hydraulic Pressure Control via Electric Motor Torque

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Solution Overview

Problem

Conventional hydraulic systems face limitations in achieving fast and accurate pressure control, as they often rely on complex and slow pressure valve systems or external sensors, which affect the precision and speed of pressure regulation.

Innovation Solution

A hydraulic system that controls the electric motor's torque based on a desired motor torque value, eliminating the need for external sensors, allowing for direct and efficient pressure control by adjusting the motor's current and torque to achieve precise pressure management within the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a pressure valve is used to control pressure in the hydraulic system, then pressure control is achieved, but the control speed and accuracy are limited

Engineering Contradiction:
Improvepressure control accuracyVSAvoidpressure control speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent replaces the mechanical pressure valve control system with an electric motor torque control system. The motor drive unit controls the electric motor's torque based on desired torque values, which directly controls the hydraulic pump's output pressure. This substitution of mechanical pressure regulation with electromagnetic torque control enables faster response times and higher precision pressure control without the inherent limitations of pressure valves.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If external pressure sensors or load cells are used for pressure feedback, then pressure control function is improved, but system complexity and cost increase

Engineering Contradiction:
Improvepressure control functionVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the electric motor self-serving by utilizing its built-in torque sensor and control system to directly control the hydraulic pump's pressure output. The motor drive unit uses the motor's own torque feedback to regulate pressure, eliminating the need for external pressure sensors or load cells. This self-service approach maintains full pressure control functionality while significantly reducing system complexity and component requirements.

Inventive Principle:
Principle #25Self-service

3Reliability

If a pressure valve system is used, then pressure control is possible, but the control system becomes slower and more complicated

Engineering Contradiction:
Improvepressure control reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the complex mechanical pressure valve control system with a streamlined electric torque control system. The motor drive unit directly controls motor torque based on desired pressure requirements, creating a simpler control architecture that maintains or improves reliability. The direct coupling between motor torque and pump pressure output eliminates the intermediate mechanical components and feedback loops required by pressure valve systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach enables fast and accurate pressure control without additional load on the control system, providing a single control loop that indirectly monitors fluid pressure through motor feedback, enhancing the system's operational efficiency and precision.

Implementation Method 1

an electric motor arranged to drive the hydraulic pump, and a motor drive unit configured to control the operation of the electric motor

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP3467307B1Pressure control of hydraulic system with electric motor
Publication Date: 2021.04.21 AUTOMATION PRESS & TOOLING AP&T AB
  • EP3467307B1 patent drawingFigure 1
  • EP3467307B1 patent drawingFigure 2
  • EP3467307B1 patent drawingFigure 3

AI summary

The present invention relates to a hydraulic system (1), wherein the system comprises a hydraulic device (10), a hydraulic pump (20) in fluid connection with the pressure chamber of the hydraulic device, an electric motor (30) arranged to drive the hydraulic pump, and a motor drive unit (40) configured to control the operation of the electric motor. The hydraulic system further comprises a control unit (50) configured to provide a desired motor torque value to the motor drive unit. The motor drive unit is configured to control the operation of the electric motor to a desired torque based on the desired motor torque value. The present invention further relates to a method of controlling pressure in a hydraulic device (10) in a hydraulic system (1).