Dual-Hydraulic Die Cushion Control for Pre-Pressurized Pad Positioning
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Solution Overview
Problem
Existing die cushion devices face challenges in effectively pre-pressurizing cushion pads when positioned at the die cushion standby position, leading to potential inaccuracies in press forming processes due to insufficient pressure control and position maintenance.
Innovation Solution
The implementation of a die cushion device with a first hydraulic cylinder for pressure control and a second hydraulic cylinder for position control, utilizing a system of hydraulic circuits, pressure commanders, and controllers to ensure the cushion pad is pre-pressurized to a preset pressure and positioned accurately at the die cushion standby position, separate from the press forming process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If hydraulic oil is prevented from flowing out from the upper chamber of the hydraulic cylinder during pre-pressurization, then the cushion pad can be pre-pressurized, but the cushion pad is slightly moved upward due to compression of hydraulic oil
Solution Approach 1:
The patent divides the single hydraulic cylinder into two separate hydraulic cylinders: a first hydraulic cylinder for pressure control (generating die cushion force) and a second hydraulic cylinder for position control (moving cushion pad in up-and-down direction). This segmentation allows independent optimization of pressure and position control, resolving the contradiction where pressure control causes position deviation.
Solution Approach 2:
The patent adds a new dimension to the control system by introducing a second hydraulic cylinder that independently controls the vertical position of the cushion pad. Instead of trying to control both pressure and position with a single cylinder, the system separates these control dimensions, allowing precise position maintenance during pre-pressurization without the cushion pad moving upward.
2Device complexity
If a single hydraulic cylinder is used for both pressure generation and position control, then the device structure is simpler, but the control precision for both pressure and position cannot be simultaneously optimized
Solution Approach 1:
The patent segments the combined pressure-position control function into two separate hydraulic cylinders: one dedicated to pressure control and another to position control. This functional segmentation enables each cylinder to be optimized for its specific control task, achieving high precision in both pressure and position simultaneously, despite the increased device complexity.
Solution Approach 2:
While using two specialized cylinders, the system maintains a unified control architecture where both cylinders work together under coordinated control signals. The first hydraulic circuit controls pressure through the first hydraulic cylinder, while the second hydraulic circuit controls position through the second hydraulic cylinder, creating a multi-functional system that achieves precise dual control.
3Manufacturing precision
If the cushion pad is pre-pressurized at the die cushion standby position, then processing accuracy is improved, but the cushion pad position may deviate due to hydraulic oil compression
Solution Approach 1:
The patent implements segmentation by separating pressure control and position control into different hydraulic cylinders. During pre-pressurization at the die cushion standby position, the first hydraulic cylinder applies pressure while the second hydraulic cylinder maintains position stability, preventing position deviation that would otherwise occur due to hydraulic oil compression.
Solution Approach 2:
The second hydraulic cylinder acts as an intermediary position-control device that compensates for position changes caused by pressure application. When the first hydraulic cylinder pressurizes the cushion pad, the second hydraulic cylinder adjusts to maintain the cushion pad at the correct standby position, serving as a mediator between pressure control and position stability.
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 solution allows for precise pre-pressurization and positioning of the cushion pad, maintaining processing accuracy, reducing surge pressure at impact, and enabling stable product quality across press machine cycles.
Implementation Method 1
a first hydraulic circuit configured to drive the first hydraulic cylinder; a first pressure commander configured to output a first pressure command indicating a die cushion pressure corresponding to the die cushion force
Implementation Method 2
a second hydraulic cylinder configured to support the cushion pad and move the cushion pad in an up-and-down direction; a second hydraulic circuit configured to drive the second hydraulic cylinder
Implementation Method 3
the hydraulic oil in the upper chamber of the hydraulic cylinder is compressed, and the cushion pad is slightly moved upward
Data Source
AI summary
The die cushion device according to the present invention includes a first hydraulic cylinder and a second hydraulic cylinder that are independently and simultaneously controlled. When a cushion pad is pre-pressurized, pressure control is performed on the first hydraulic cylinder via a first hydraulic circuit so that a pressure in a lower chamber of the first hydraulic cylinder is pre-pressurized to a preset pressure, and position control is simultaneously performed on the second hydraulic cylinder via a second hydraulic circuit so that the cushion pad is held in the die cushion standby position. A force with which the first hydraulic cylinder moves the cushion pad upward is balanced with a force with which the second hydraulic cylinder moves the cushion pad downward (a force for holding the die cushion standby position).