Three-Position Cylinder Pressure Control for Stable Intermediate Stops
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Solution Overview
Problem
Existing three-position control devices face challenges in accurately and quickly stopping a piston at the intermediate position due to time lags and instability, making rapid and stable positioning difficult.
Innovation Solution
A three-position control device with a cylinder device, fluid control unit, and displacement restriction device that uses different working pressures and a biasing mechanism to control piston movement, allowing quick and stable positioning at intermediate and advanced positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-pressure air is introduced into both air chambers at the timing when the magnetic sensor detects the intermediate position, then the piston is pressed from both sides to stop at the intermediate position, but a time lag occurs between detection and actual braking, making it difficult to stop with high accuracy
Solution Approach 1:
The patent introduces high-pressure air into the air chambers in advance before the piston reaches the intermediate position. The fluid control unit is configured to introduce high-pressure air into the first air chamber in advance, and then introduce high-pressure air into the second air chamber when the piston reaches the intermediate position. This preliminary action eliminates the time lag between detection and braking, allowing the piston to stop accurately at the intermediate position without waiting for sensor detection and signal processing.
2Reliability
If high-pressure air is introduced into both air chambers to stop the piston at the intermediate position, then braking force is applied, but the piston cannot be displaced rapidly due to the counteracting forces
Solution Approach 1:
The patent uses periodic switching of air pressure states to achieve both rapid movement and stable positioning. The fluid control unit alternates between introducing high-pressure air into the first air chamber (for rapid movement to intermediate position) and introducing high-pressure air into the second air chamber (for stable positioning at intermediate position). This periodic action allows the piston to move rapidly when needed and remain stable when required, resolving the contradiction between speed and stability.
3Stability of the object's composition
If air pressure is balanced on both sides of the piston to hold it at the intermediate position, then the piston is held in place, but it becomes difficult to stably stop the piston and control object
Solution Approach 1:
The patent introduces high-pressure air into the first air chamber in advance, creating an asymmetric pressure distribution before the piston reaches the intermediate position. This asymmetric pressure state provides a pre-positioning force that complements the subsequent balanced pressure state, enhancing the stability of the stopped state. The asymmetric preliminary action ensures the piston is properly positioned and stabilized when the balanced pressure is applied.
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 rapid and accurate displacement to intermediate and advanced positions, with stable maintenance at the intermediate position, improving positioning accuracy and stability.
Implementation Method 1
high-pressure air is introduced into one air chamber, and air in the other air chamber is discharged to the outside
Implementation Method 2
high-pressure air is introduced into the other air chamber, and air in the one air chamber is discharged to the outside
Implementation Method 3
a spring member that biases the load receiving portion in a direction against a load input from the piston
Implementation Method 4
high-pressure air is introduced into the two air chambers at the front and rear of the piston at a timing when the magnetic sensor detects that the piston has been displaced to the intermediate position. This causes the piston to be pressed by the high-pressure air from both the front and rear sides, and the piston stops at the intermediate position together with the control object
Data Source
AI summary
A three-position control device includes a cylinder device, a fluid control unit, and a displacement restriction device. The cylinder device displaces a piston to each of a retracted position, an intermediate position, and an advanced position. The cylinder device has a first fluid chamber for retraction and a second fluid chamber for advance. A fluid control unit switches an advanced/retracted position of the piston. A second working pressure during displacement from an intermediate position to the advanced position is set to be greater than a first working pressure during displacement from the retracted position to the intermediate position. The displacement restriction device has a load receiving portion and a biasing means. A biasing force of the biasing means is set to be greater than a thrust caused by the first working pressure and smaller than a thrust caused by the second working pressure.