Hydraulic Actuator Control via Common Electric Motor

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Solution Overview

Problem

Existing hydraulic systems for mobile work machines are inefficient due to the need for complex control valves and energy losses associated with hydraulic control elements, which complicate operation and increase energy consumption.

Innovation Solution

A hydraulic system utilizing two pumps connected to a common electric motor, where the pumps have inverse pumping characteristics, allowing the motor to control the actuator's speed and direction without separate hydraulic control elements, and using a simple ON/OFF distribution system to minimize throttling and power losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If complex hydraulic control valves and control elements are used to control hydraulic actuators, then precise control of actuator speed and direction is achieved, but energy losses increase and system efficiency decreases

Engineering Contradiction:
Improvecontrol precisionVSAvoidenergy efficiency
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The invention extracts and removes the hydraulic control valves and control elements from the system. Instead of using traditional hydraulic control methodology, the system directly controls the electric motor driving the pumps, thereby eliminating the energy losses associated with hydraulic control elements while maintaining precise control capability through electronic control of the motor speed and direction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical hydraulic control system with an electrical control system. The electric motor's speed and rotation direction are controlled electronically, which substitutes the traditional mechanical hydraulic valves and control elements, achieving both precise control and improved energy efficiency.

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

2Adaptability or versatility

If multiple hydraulic control elements and valves are installed in the hydraulic circuit, then control functionality is enhanced, but device complexity increases

Engineering Contradiction:
Improvecontrol functionalityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention extracts and removes multiple hydraulic control elements and valves from the hydraulic circuit. By controlling the electric motor directly, the system achieves the necessary control functionality without requiring complex hydraulic valve assemblies, thereby significantly reducing device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the control functions of multiple hydraulic elements into a single electric motor control system. The motor controller integrates speed control, direction control, and flow regulation that were previously distributed across multiple separate hydraulic valves and control elements.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If traditional hydraulic control systems with separate control elements are used, then comprehensive control of hydraulic actuators is achieved, but the system requires more components and maintenance

Engineering Contradiction:
Improvecontrol capabilityVSAvoidnumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention merges the functions of multiple separate hydraulic control elements into a single integrated electric motor control system. The motor controller provides comprehensive control of actuator speed and direction by directly controlling the motor, eliminating the need for separate hydraulic valves, flow controllers, and pressure regulators.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electric motor serves multiple functions simultaneously: it drives the hydraulic pumps, controls the flow rate through speed variation, and determines the direction of hydraulic fluid flow through rotation direction. This multi-functionality replaces what previously required multiple specialized control components.

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 simplifies the hydraulic system, reduces energy losses, and allows for efficient control of hydraulic actuators without the need for complex control valves, enhancing the robustness and energy efficiency of the system while maintaining the advantages of hydraulic power transmission.

Implementation Method 1

Pressure of the hydraulic fluid prevailing in the first working pressure space or volume and the second pressure space or volume are configured to cause inversely directed forces for a moving element of the actuator

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

One common electric motor is configured to rotate the mentioned two hydraulic pumps simultaneously

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP3536864B1Hydraulic system and method of controlling hydraulic actuator
Publication Date: 2020.12.30 SANDVIK MINING & CONSTR OY
  • EP3536864B1 patent drawingFigure 1~3
  • EP3536864B1 patent drawingFigure 4~5
  • EP3536864B1 patent drawingFigure 6

AI summary

The invention relates to a hydraulic system, a mobile mining machine and to a method of controlling a hydraulic actuator. The hydraulic system comprises two hydraulic pumps (PI, P2) for generating hydraulic power for a hydraulic actuator (HA). The pumps are powered by means of a common electric motor (M). Operation of the actuator is controlled by controlling speed and direction of the motor, whereby hydraulic lines (19a, 19b) may be without actively controlled control valves.