Screw-Pump Electro-Hydraulic Actuator Without External Fluid Supply
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Solution Overview
Problem
Existing heavy-duty machinery relies on hydraulic cylinders for high precision and shock resistance but requires frequent maintenance and an external hydraulic fluid supply, making them unsuitable for harsh environments and heavy loads.
Innovation Solution
A screw-pump type electro-hydraulic actuator that combines an electric motor, hydraulic tube, pump piston, spline rod, and hydraulic control circuit to provide high precision movement without external hydraulic fluid, with shock-absorbing capabilities and reduced maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic cylinder is used for high precision movement and shock resistance, then shock absorbing characteristics are improved, but maintenance requirements increase and external hydraulic fluid supply is needed
Solution Approach 1:
The patent combines the hydraulic cylinder and external hydraulic fluid supply system into a single integrated unit. The electro-hydraulic actuator contains an internal hydraulic pump driven by an electric motor that generates hydraulic fluid on-demand, eliminating the need for an external hydraulic reservoir and fluid supply system while maintaining shock absorbing capabilities through the integrated hydraulic circuit.
Solution Approach 2:
The actuator serves itself by generating its own hydraulic fluid through an internal pump mechanism. The electric motor drives the pump to create hydraulic pressure and flow as needed for actuation and shock absorption, without requiring external hydraulic fluid supply infrastructure, thereby reducing maintenance requirements and system complexity.
2Force
If a hydraulic cylinder is used for heavy load handling, then load handling capability is improved, but maintenance requirements increase
Solution Approach 1:
The integrated electro-hydraulic actuator generates its own hydraulic fluid internally through an electric motor-driven pump, eliminating the need for external hydraulic reservoirs, fluid lines, and associated maintenance. The sealed internal hydraulic circuit reduces leakage risks and maintenance requirements while maintaining heavy load handling capability through high-pressure hydraulic actuation.
Solution Approach 2:
The patent extracts and eliminates the external hydraulic fluid supply system from traditional hydraulic cylinders. By removing the external reservoir, fluid lines, and filtration systems, the design reduces maintenance requirements while retaining the core hydraulic force generation capability through an integrated electric motor and pump assembly.
3Measurement precision
If an electric linear actuator is used for high precision and speed, then precision and speed are improved, but suitability for harsh environments and heavy loads decreases
Solution Approach 1:
The patent applies hydraulic principles by using an electric motor-driven pump to generate high-pressure hydraulic fluid that acts on a piston, enabling the actuator to handle heavy loads and operate in harsh environments. This hydraulic mechanism provides high force density and robustness while the electric motor control maintains precision and speed performance.
Solution Approach 2:
The invention merges the precision control advantages of electric actuators with the heavy-duty capabilities of hydraulic systems. The electric motor provides precise speed and position control, while the integrated hydraulic pump and piston mechanism delivers high force and robustness for harsh environments, combining both sets of advantages in a single actuator unit.
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 screw-pump type electro-hydraulic actuator achieves high precision movement, supports heavy loads, operates in hostile environments, and eliminates the need for external hydraulic fluid, offering improved reliability and reduced maintenance.
Implementation Method 1
The screw pump type actuator includes a pump piston with three sets of screw pump rollers that pump hydraulic fluid from a first chamber to a second chamber
Implementation Method 2
The accumulator will be set to provide hydraulic oil flow to compensate for hydraulic oil volume differences
Implementation Method 3
The hydraulic flow circuit includes a first relief valve, a first check valve, a second relief valve, a second check valve and an accumulator
Implementation Method 4
The hydraulic flow circuit includes a first relief valve, a first check valve, a second relief valve, a second check valve and an accumulator
Data Source
AI summary
A screw-pump type electro-hydraulic actuator preferably includes an electric motor device, a hydraulic tube, a pump piston, a spline rod, an actuator rod and a hydraulic control circuit. The electric motor device preferably includes an electric motor and a gearbox. One end of the spline rod is engaged with an output of the gearbox. The pump piston preferably includes a piston base, three sets of screw pump rollers, a spline drive gear, a first piston end plate and a second piston end plate. The hydraulic flow circuit includes a first relief valve, a first check valve, a second relief valve, a second check valve and an accumulator. The screw pump rollers are rotatably retained in the piston base between the first and second piston end plates. The spline gear drives the pump driven gears of the three drive screw pump rollers through the spline drive gear to pump hydraulic oil.