Hydraulic Linear Actuator Locking Valve for Compression Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hydraulic linear actuators lack a system for selectively locking the compression movement, limiting their versatility in applications requiring directional control.
Innovation Solution
A hydraulic linear actuator design incorporating an inner cylindrical tube, a blind plunger, a rod, an outer cylindrical tube with a pressurized gas and oil reservoir, an intermediate cylindrical tube, a check valve, and an electrically-operated flow control valve that allows movement in both directions or only in the extension direction by controlling oil flow between chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a hydraulic linear actuator is designed without a locking system, then the structure remains simple, but the actuator cannot selectively lock compression movement, limiting its versatility
Solution Approach 1:
The patent implements a nested three-tube structure where an inner cylindrical tube is placed inside an intermediate cylindrical tube, which is in turn placed inside an outer cylindrical tube. This nesting arrangement allows multiple chambers (compression chamber, extension chamber, and reservoir chamber) to coexist in a compact configuration, enabling the locking system functionality without proportionally increasing the overall device size.
Solution Approach 2:
The patent introduces an intermediate cylindrical tube as a mediator between the inner and outer tubes. This intermediate tube creates the reservoir chamber and provides a structural bridge that facilitates the implementation of the locking system. The intermediate tube allows oil to be stored in the reservoir chamber while maintaining communication pathways for controlled flow, enabling selective locking without requiring a completely redesigned architecture.
2Adaptability or versatility
If a locking system is added to control oil flow between chambers, then compression movement can be locked, but the device complexity increases
Solution Approach 1:
The electrically-operated valve is designed to perform multiple functions: it controls oil flow between the compression chamber and reservoir chamber, enables selective locking of compression movement, and allows the actuator to operate in different modes (free compression, locked compression, free extension). This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in device complexity despite the added locking capability.
Solution Approach 2:
The patent extracts the locking function from the main actuator body by using a separate electrically-operated valve that controls oil flow between specific chambers. This extracted valve system can be independently controlled and maintained, allowing the locking functionality to be added without fundamentally redesigning the entire actuator structure. The valve acts as a discrete controllable element that can be integrated into the existing three-tube architecture.
3Length of moving object
If the actuator uses a compact three-tube design, then the axial size is reduced, but the integration of locking system becomes more challenging
Solution Approach 1:
The compact axial size is achieved through the nested three-tube configuration where tubes are arranged concentrically along the same axis. The inner tube contains the compression and extension chambers, the intermediate tube creates the reservoir chamber, and all components are integrated along the longitudinal axis. This nesting allows the locking system to be integrated without significantly increasing the axial length, as the valve and associated components are incorporated within the existing tubular structure.
Solution Approach 2:
The patent utilizes the radial dimension by arranging tubes concentrically, allowing multiple chambers to exist at different radial levels rather than extending axially. The compression chamber, extension chamber, and reservoir chamber are positioned at different radial distances from the central axis, enabling compact axial packaging. The valve system is integrated within this radial arrangement, controlling flow between chambers without requiring additional axial space.
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 selective locking of compression movement, reducing the actuator's axial size while maintaining travel distance, and allowing easy integration with existing three-tube hydraulic dampers, enhancing application versatility, particularly in roll control systems for motor vehicles.
Implementation Method 1
a check valve associated to the inner cylindrical tube to allow the oil to flow in the direction from the reservoir chamber to the compression chamber only
Implementation Method 2
an electrically-operated flow control valve associated to the intermediate cylindrical tube to control the flow of the oil between the intermediate chamber and the reservoir chamber
Implementation Method 3
an outer cylindrical tube which is arranged coaxially to the inner cylindrical tube and encloses with the latter a reservoir chamber containing a pressurized gas in a first portion thereof and oil in the remaining portion
Data Source
AI summary
The actuator comprises a cylinder and a rod. The cylinder comprises an inner cylindrical tube and an outer cylindrical tube which extend coaxially to each other along a longitudinal axis (z). The inner cylindrical tube accommodates a plunger which is rigidly connected to the rod and separates an inner volume of the inner cylindrical tube into a compression chamber and an extension chamber, wherein at least the compression chamber contains oil. The inner cylindrical tube and the outer cylindrical tube enclose with each other a reservoir chamber which is permanently in fluid communication with the extension chamber via at least one first passage provided in the inner cylindrical tube and contains a pressurized gas in a first portion thereof and oil in a remaining portion thereof. The cylinder further comprises an intermediate cylindrical tube which extends along the longitudinal axis (z) between the inner cylindrical tube and the outer cylindrical tube and encloses, along with the inner cylindrical tube, an intermediate chamber permanently in fluid communication with the compression chamber via at least one second passage provided in the inner cylindrical tube. The actuator further comprises a check valve associated to the inner cylindrical tube to allow the oil to flow in the direction from the reservoir chamber to the compression chamber only, and an electrically-operated flow control valve which is associated to the intermediate cylindrical tube for controlling the flow of the oil between the intermediate chamber and the reservoir chamber. The flow control valve is movable between a first operating position, in which it allows the oil to flow between the intermediate chamber and the reservoir chamber, and a second operating position, in which it prevents the oil from flowing between the intermediate chamber and the reservoir chamber.