Hydraulic Actuator Layout With Internal Pressure Amplification

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Solution Overview

Problem

Existing hydraulic actuator arrangements face challenges in compact design usability, as they often require additional space for components and struggle to produce sufficient force to lift larger loads while maintaining compactness.

Innovation Solution

Integrating a hydraulic pressure amplifier between the hydraulic pump and pressure chamber, with the motor and pump arranged within the piston rod, allowing for increased pressure and reduced space requirements, and incorporating an accumulator and buffer tank for pressure balancing and temperature compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the actuator is designed compactly, then the space requirement is reduced, but the force output capability deteriorates

Engineering Contradiction:
Improveactuator volumeVSAvoidforce output
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The pump and motor are integrated within the piston rod's internal volume, nesting components inside each other and within the actuator structure. This allows the force-generating components to occupy space that would otherwise be empty, enabling compact design without sacrificing force output capability

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The pressure amplifier introduces a pressure multiplication dimension to the system. By amplifying the pressure from the pump before it acts on the piston, the system achieves higher force output from the same compact volume, effectively adding a pressure amplification dimension to overcome the volume-force tradeoff

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Force

If the pressure amplifier is added to increase force, then the force output is improved, but the device complexity increases

Engineering Contradiction:
Improveforce outputVSAvoidsystem complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The pressure amplifier is integrated with the pump and motor assembly within the piston rod, merging multiple functions (pressure generation, amplification, and actuation) into a single compact unit. This reduces the number of separate components and connections needed, thereby reducing overall system complexity despite adding pressure amplification capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pressure amplifier is controlled to activate automatically based on system pressure requirements. The switching means detects when amplified pressure is needed and activates the pressure amplifier accordingly, eliminating the need for external control systems and reducing operational complexity

Inventive Principle:
Principle #25Self-service

3Volume of moving object

If the motor and pump are integrated in the piston rod, then the space requirement is reduced, but the heat dissipation capability deteriorates

Engineering Contradiction:
Improveactuator volumeVSAvoidmotor temperature
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The motor is positioned in the section of the piston rod that extends out of the cylinder when the piston rod is extracted. This extraction exposes the motor to ambient air for passive cooling, taking the heat dissipation function outside the sealed cylinder environment where cooling would be poor

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

When the piston rod is in the retracted position, the motor is cooled by the oil volume surrounding it within the piston rod. The hydraulic oil serves as a cooling medium, transferring heat from the motor to the hydraulic fluid system

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 hydraulic actuator to produce larger forces without additional space, with the ability to automatically activate the pressure amplifier for higher pressures, and maintains compactness by integrating all components within the piston rod, ensuring efficient energy use and cooling.

Implementation Method 1

a hydraulic pressure amplifier is arranged between the hydraulic pump and the pressure chamber, wherein the motor and the pump are arranged in the piston rod

Methodology Applied
Scientific EffectHydraulic pressure amplification: Hydraulic Press

Implementation Method 2

an electric motor driving the hydraulic pump

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

a hydraulic pump connected to the pressure chamber

Methodology Applied
Scientific EffectHydraulic pumping: Pump

Implementation Method 4

an accumulator is arranged within the cylinder housing. The accumulator is used to balance the oil volume when the pressure chamber and a retraction chamber have different pressure areas

Methodology Applied
Scientific EffectCompressed air storage: Compression

Implementation Method 5

the motor is arranged in a section of the piston rod surrounded by an oil volume, when the piston rod is in a retracted position. The motor is at least partly oil-cooled

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3730806B1Hydraulic actuator arrangement
Publication Date: 2023.01.18 PISTON POWER SRO
  • EP3730806B1 patent drawingFigure 1~2
  • EP3730806B1 patent drawingFigure 3

AI summary

A hydraulic actuator arrangement (1) is described comprising a hydraulic actuator having a pressure chamber (2), a cylinder (3) in a cylinder housing (4), and a piston (5) connected to a piston rod, a hydraulic pump (7) connected to the pressure chamber (2) and an electric motor (8) driving the hydraulic pump (7), wherein the pump (7) and the motor (8) are arranged within the actuator. Such an actuator arrangement should have many application possibilities. To this end, a hydraulic pressure amplifier (10) is arranged between the hydraulic pump (7) and the pressure chamber (2)