Dual Piston Actuator Spring Mounting and Fluid Lubrication
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Solution Overview
Problem
Conventional spring-driven pressure fluid return type actuators have limited force advancement for the second piston due to the positioning of the second spring between the first and second pistons, and require frequent maintenance of the ball-type switching mechanism.
Innovation Solution
The second spring is mounted between the housing inner wall and the second piston, allowing its urging force to directly advance the second piston, and the switching mechanism is placed within the pressure fluid chamber for self-lubrication using pressure oil or compressed air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the second spring is mounted between the first piston and the second piston, then the structure is compact, but the urging force of the second spring cannot directly advance the second piston, limiting the force advancement
Solution Approach 1:
The second spring is extracted from its conventional position between the first piston and second piston, and relocated to be mounted between the inner wall of the housing and the second piston. This extraction allows the second spring to directly apply its urging force to the second piston, enabling both springs to contribute to advancing the second piston simultaneously.
2Reliability
If the ball-type switching mechanism is disposed outside the pressure fluid chamber, then the structure is simple, but frequent maintenance is required due to lack of lubrication
Solution Approach 1:
The switching mechanism is merged with the pressure fluid chamber by disposing it inside the chamber. This integration allows the pressure fluid (oil or compressed air) to serve dual purposes: both actuating the pistons and providing continuous lubrication to the switching mechanism, thereby eliminating the need for separate lubrication systems and reducing maintenance requirements.
Solution Approach 2:
The pressure fluid within the chamber serves itself by automatically lubricating the switching mechanism components that are in contact with it. This self-service arrangement ensures continuous lubrication without external intervention, allowing the switching mechanism to operate smoothly over extended periods without maintenance.
3Ease of operation
If the switching mechanism is disposed outside the pressure fluid chamber, then lubrication can be applied, but periodic maintenance is still required
Solution Approach 1:
The pressure fluid continuously lubricates the switching mechanism components immersed in it, creating a self-service system that automatically maintains the mechanism without requiring periodic external lubrication or maintenance interventions, thereby eliminating maintenance time loss.
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 increases the force advancement of the second piston and simplifies maintenance by using pressure fluid for lubrication, ensuring smooth operation over a longer period.
Implementation Method 1
a first spring for high load is mounted between a lower end wall of the housing and the first piston, and a second spring for low load is mounted between an inner wall of the housing and the second piston
Implementation Method 2
when a pressure oil (or compressed air containing a lubricating oil) is used as a pressure fluid, it is possible to sufficiently lubricate the switching mechanism 27 by the pressure oil (or the compressed air containing the lubricating oil)
Data Source
AI summary
A first piston (20) for high load is inserted into a housing (18) so as to be movable vertically, and a second piston (22) for low load is inserted into a cylindrical hole (40) of the first piston (20) so as to be movable vertically. An output portion (22b) projects from the second piston (22) to above the housing (18). A first spring (24) for high load and a second spring (26) for low load are mounted in a spring chamber (44) defined by both pistons (20) and (22). Both springs (24) and (26) are mounted so as to urge the first piston (20) and the second piston (22) upward. A switching mechanism (27) disposed in the pressure fluid chamber (46) at a side opposite to the spring chamber (44), connects the first piston (20) selectively to the housing (18) or the second piston (22).