Servo Die Cushion Speed Control via Slide Feedback
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Solution Overview
Problem
Conventional die cushion mechanisms using hydraulic or pneumatic units cannot vary pressure effectively in response to the amount of drawing, leading to reduced press force and incomplete machining due to divergent die cushion speed from slide speed.
Innovation Solution
A control device for a servo die cushion that generates a speed command for the die cushion, ensuring its speed does not diverge significantly from the slide speed by using a threshold calculated based on the slide speed, either by adding a positive value or multiplying by a constant, to maintain consistent press force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the die cushion speed command is calculated using conventional equations based on force error, then the force control response is fast, but the die cushion speed diverges from the slide speed causing press force reduction
Solution Approach 1:
The control device uses feedback from the slide speed detection to dynamically adjust the die cushion speed command. The detected slide speed is fed back into the control system to calculate a threshold value, which then constrains the die cushion speed command to remain within an acceptable range relative to the actual slide speed, preventing divergence and maintaining press force consistency
Solution Approach 2:
The system dynamically adjusts the die cushion speed command by incorporating real-time slide speed information. The threshold value calculated from detected slide speed creates a dynamic constraint that adapts to changing operating conditions, allowing the die cushion speed to follow the slide speed accurately without using complex conventional speed calculation equations
2Adaptability or versatility
If hydraulic or pneumatic units are used as driving sources, then the structure is simple, but the pressure cannot be varied in response to the amount of drawing
Solution Approach 1:
The patent replaces hydraulic or pneumatic driving systems with a servomotor-driven mechanical system. This substitution enables precise electronic control of the die cushion speed command through software algorithms that calculate thresholds based on detected slide speed, allowing pressure and force to be varied dynamically in response to drawing amount without the structural complexity of hydraulic control valves or pneumatic pressure regulators
Data Source
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AI summary
A control device (10), for a servo die cushion, by which the speed of a die cushion (3) is prevented from largely deviating from the speed of a slide (2), whereby the press force between the slide (2) and the die cushion (3) is not significantly reduced. The control device (10) includes a slide speed detector (14) for detecting the speed of the slide, a die cushion speed detector (16) for detecting the speed of the die cushion, and a die cushion speed commanding part (18) for controlling the speed of the die cushion. When a tentative speed command of the die cushion is largely deviated from the detected slide speed, the command of the die cushion is corrected such that the absolute value thereof does not exceed the value calculated by adding the absolute value of the detected slide speed to a positive constant.