Injection Cylinder Speed Control via Feedback Valve
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Solution Overview
Problem
Current injection apparatuses face challenges in achieving high precision speed control, particularly at the start of injection, due to limitations in controlling the waveform of injection speed, which affects the quality of molded articles.
Innovation Solution
The injection apparatus incorporates an injection cylinder with a piston rod, a piston, and a cylinder part partitioned into chambers, a liquid pressure source, a pressure sensor, a flow control valve, and a control device that includes an open control part, a target speed setting part, and a command value setting part to precisely control the flow rate of hydraulic fluid, allowing for feedback control and correction based on detected pressures and positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control based on plunger speed is used, then speed control is achieved, but precision of speed control at the start of injection is insufficient
Solution Approach 1:
The patent implements feedback control by detecting the actual speed of the plunger during injection and comparing it with the target speed waveform, then adjusting the flow control valve to minimize the deviation. This closed-loop control system continuously monitors and corrects speed deviations, achieving high precision speed control at the start of injection where rapid response is critical.
Solution Approach 2:
The patent replaces traditional mechanical speed control mechanisms with an electronically controlled flow control valve that responds to electrical signals from the control device. This substitution enables faster response times and more precise control at the start of injection, as electronic control can rapidly adjust valve opening based on real-time speed feedback without mechanical inertia delays.
2Ease of operation
If injection speed waveform is simplified for control, then control becomes easier, but quality of molded article deteriorates
Solution Approach 1:
The patent employs dynamic speed waveform control where the target speed varies continuously during the injection process rather than maintaining a fixed pattern. The control device calculates optimal speed waveforms based on real-time conditions, allowing the injection speed to dynamically adapt to filling requirements, thereby maintaining both control feasibility and molded article quality.
Solution Approach 2:
The patent changes multiple control parameters including injection speed, flow rate, and valve opening degree during the injection process. By dynamically adjusting these parameters based on the progression of injection and detected deviations, the system achieves complex speed waveforms that ensure high molded article quality while remaining within controllable parameter ranges.
3Device complexity
If flow control valve responds slowly, then device complexity is reduced, but speed control precision deteriorates
Solution Approach 1:
The patent introduces a control device as an intermediary between the flow control valve and the injection system. This control device processes speed feedback signals, calculates required valve adjustments, and outputs precise control signals to the flow control valve. The intermediary enables rapid response and high precision speed control without requiring the flow control valve itself to be overly complex, as the control logic is centralized in the control device.
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 enhances the precision of speed control at the start of injection, improving the quality of molded articles by allowing for more accurate and responsive speed adjustments.
Implementation Method 1
a liquid pressure source which can supply a hydraulic fluid to the head-side chamber
Implementation Method 2
a flow control valve which can control a flow rate of the hydraulic fluid discharged from the rod-side chamber
Implementation Method 3
a head-use pressure sensor which can detect a pressure of the head-side chamber
Data Source
AI summary
In an injection cylinder which can be connected with a plunger, the internal portion of the cylinder part is partitioned by a piston into a rod-side chamber on the side of the piston rod and a head-side chamber on the opposite side. An accumulator can supply a hydraulic fluid to the head-side chamber. A head-use pressure sensor can detect a pressure of the head-side chamber. A flow control valve can control a flow rate of the hydraulic fluid discharged from the rod-side chamber. A control device includes an OP control part which starts open control driving the flow control valve to the opening direction after the start of supply of the hydraulic fluid from the accumulator to the head-side chamber conditional on the detection pressure of the head-use pressure sensor rising up to the predetermined set value.