Multi-Material Fluid Actuator for Lower Cylinder Weight
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Solution Overview
Problem
Existing fluid actuators are heavy due to the use of rigid materials like stainless steel, making it difficult to reduce their weight while maintaining necessary rigidity for pressure and impact resistance.
Innovation Solution
The fluid actuator design incorporates a cylinder with alternating sections made of iron-based and aluminum alloys, where the piston rod is also made of iron-based alloy, allowing for reduced weight by using aluminum alloys for less critically loaded areas and maintaining rigidity where necessary, along with a manifold and hydraulic circuit made of aluminum alloy to minimize weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If highly rigid materials such as stainless steel are used for the cylinder and other members, then the actuator can withstand fluid pressure and external impacts, but the weight of the fluid actuator increases significantly
Solution Approach 1:
The cylinder is constructed with different materials for different sections: iron-based alloy for the first and last sections (which require high strength for pressure and impact resistance), and aluminum alloy for the intermediate sections (which have lower strength requirements). This local differentiation allows weight reduction in non-critical areas while maintaining necessary strength in critical areas.
Solution Approach 2:
The cylinder employs a composite structure combining iron-based alloy and aluminum alloy sections. The iron-based alloy provides high strength for withstanding fluid pressure and external impacts, while the aluminum alloy sections reduce overall weight. This composite material approach resolves the contradiction between strength and weight by utilizing the complementary properties of different materials in appropriate locations.
2Strength
If the entire cylinder is made of iron-based alloy to ensure high rigidity, then the actuator can withstand external impacts and fluid pressure, but the overall weight of the actuator increases
Solution Approach 1:
The cylinder is constructed with different materials for different sections: iron-based alloy for the first and last sections (which require high strength for pressure and impact resistance), and aluminum alloy for the intermediate sections (which have lower strength requirements). This local differentiation allows weight reduction in non-critical areas while maintaining necessary strength in critical areas.
3Weight of stationary object
If aluminum alloy is used for the manifold and hydraulic circuit, then the weight of the fluid actuator is reduced, but the rigidity and durability in pressure-bearing areas may be compromised
Solution Approach 1:
The manifold and hydraulic circuit are made of aluminum alloy in areas where high pressure resistance is not critical, reducing overall weight. The cylinder sections that directly bear fluid pressure and external impacts use iron-based alloy to maintain necessary strength and durability. This localized material selection optimizes the weight-strength trade-off.
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 configuration reduces the overall weight of the fluid actuator while maintaining the required rigidity and durability, particularly around mounting and pressure-bearing areas, and ensures the piston rod's stability through balanced fluid chamber volumes and dedicated hydraulic circuits.
Implementation Method 1
the piston rod being configured to reciprocate in the axial direction in accordance with pressures in the plurality of fluid chambers
Data Source
AI summary
One object is to reduce a weight of a fluid actuator. The fluid actuator includes: a cylinder having an inner space and a first mounting portion, the inner space being partitioned into a first fluid chamber and a second fluid chamber, the first mounting portion being disposed on an end portion of the cylinder on an axial direction A side; and a piston rod configured to reciprocate in accordance with pressures in the fluid chambers. A wall portion defining the first fluid chamber in the cylinder is made of an iron-based alloy. A wall portion defining the second fluid chamber in the cylinder is made of an aluminum alloy. The piston rod is made of an iron-based alloy.