Hydraulic Swing-Back Valve for Stable Actuator Stop States
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing swing-back preventing apparatuses for hydraulic actuators fail to effectively prevent operation due to undesired loads when the system is in a stop state, as they allow communication between ports even when differential pressure is zero, leading to unwanted operation.
Innovation Solution
A swing-back preventing apparatus with a piston that moves between offset and neutral positions based on liquid pressure differences, using biasing members and communication passages to block or connect ports, and flow rate control spools to manage liquid flow, ensuring the ports communicate only when necessary to minimize swing-back.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the communication passage is kept open when differential pressure is zero, then the hydraulic actuator can perform pumping operation, but the hydraulic actuator operates undesirably when stopped on an oblique surface due to own weight
Solution Approach 1:
The communication passage is made dynamically controllable through a valve mechanism that adjusts its state based on operating conditions. The valve opens the communication passage during pumping operations to maintain productivity, and closes it during stop states to prevent undesired operation due to gravitational loads on oblique surfaces.
Solution Approach 2:
The system changes the flow resistance parameter of the communication passage between two states: low resistance (open) during pumping to enable operation, and high resistance (closed) during stopping to prevent swing-back. This parameter switching resolves the contradiction between productivity and reliability.
2Reliability
If the communication passage is closed to prevent swing-back, then the hydraulic actuator cannot perform pumping operation
Solution Approach 1:
The valve mechanism dynamically controls the communication passage state, opening it during pumping operations to maintain productivity and closing it during stop states to prevent swing-back, thus resolving the contradiction between reliability and productivity.
Solution Approach 2:
The communication passage alternates between open and closed states based on the operational phase: open during pumping cycles to enable operation, and closed during stopping phases to prevent swing-back. This periodic switching resolves the contradiction.
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
Prevents hydraulic actuators from operating due to undesired loads by ensuring the piston returns to a neutral position, blocking communication between ports and thus reducing the occurrence and speed of swing-back phenomena.
Implementation Method 1
a piston (22) which receives a liquid pressure of the first port (31) and a liquid pressure of the second port (32) so that these liquid pressures act against each other, and moves to a position corresponding to a differential pressure between the liquid pressure of the first port (31) and the liquid pressure of the second port (32)
Implementation Method 2
a pair of biasing members (27L, 27R) which act against the liquid pressure of the first port (31) and the liquid pressure of the second port (32), and bias the piston (22) so as to return to a neutral position
Data Source
AI summary
Provided is a swing-back preventing apparatus capable of preventing a hydraulic actuator in a stop state from operating by undesired load. The swing-back preventing apparatus includes a housing, a piston, and a pair of biasing members. First and second spaces are formed between the piston and the housing, and the piston includes a pair of communication passages that are communicable with first and second spaces. When the piston is located at a first offset position, the first space is blocked from a first port. When the piston separates from the first offset position, the first space is connected to the first port. When the piston is located at a second offset position, the second space is blocked from a second port. When the piston separates from the second offset position, the second space is connected to the second port. When the piston is located at a position on the first offset position side of a neutral position, a first communication passage is connected to the first space. When the piston is located in a range from the neutral position to the second offset position, the first communication passage is blocked from the first space. When the piston is located at a position on the second offset position side of the neutral position, a second communication passage is connected to the second space. When the piston is located in a range from the neutral position to the first offset position, the second communication passage is blocked from the second space.