Die Cushion-Cum-Slide Cushion Device with Selector Valve
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Solution Overview
Problem
Conventional die cushion devices using servo motors are expensive due to the need for large-capacity motors and result in low energy efficiency, as the servo motor does not operate during most of the pressing cycle and causes pressure loss when used with proportional valves.
Innovation Solution
A die cushion-cum-slide cushion device that utilizes a servo motor to generate both slide cushion and die cushion forces by selectively supplying pressure fluid to fluid-pressure cylinders through a selector valve, allowing the servo motor to operate during surplus periods and improving energy efficiency through regenerative energy systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a servo motor of large capacity is used to supply all power required for die cushioning simultaneously, then the die cushion force capability is improved, but the device size and power-receiving equipment capacity increase
Solution Approach 1:
The cushioning function is segmented into two separate systems: a die cushion system that operates only during die cushioning (when the press machine is not pressing), and a slide cushion system that operates during slide cushioning (when the press machine is pressing). This segmentation allows each servo motor to be sized appropriately for its specific function rather than requiring one oversized motor to handle both functions simultaneously, thereby reducing the device size while maintaining sufficient force capability for each function.
2Force
If a servo motor of large capacity is used to supply all power required for die cushioning simultaneously, then the die cushion force capability is improved, but the power-receiving equipment capacity increases
Solution Approach 1:
The power requirement is segmented by separating the die cushioning operation from the slide cushioning operation in time. The die cushion servo motor only needs to supply power during die cushioning (when the press machine is not pressing), and the slide cushion servo motor only needs to supply power during slide cushioning (when the press machine is pressing). This temporal segmentation reduces the peak power requirement for each motor compared to a single motor that would need to handle both functions simultaneously, thereby reducing the power-receiving equipment capacity.
3Volume of stationary object
If a proportional valve is used to reduce servo motor capacity, then the servo motor size is reduced, but pressure loss occurs and energy efficiency decreases
Solution Approach 1:
The proportional valve is extracted from the system and replaced with a direct connection between the servo motor and the cushioning cylinder. The servo motor directly controls the hydraulic pump that supplies pressure fluid to the cushioning cylinder without passing through a proportional valve. This eliminates the pressure loss associated with proportional valve operation while still allowing the servo motor to be sized appropriately for the specific cushioning function it serves.
4Manufacturing precision
If the servo motor is used only for die cushioning, then the die cushion force is applied accurately, but the servo motor does not operate during most of the pressing cycle period reducing its value
Solution Approach 1:
The servo motor system is designed with multi-functionality by implementing two separate servo motors: one dedicated to die cushioning and another dedicated to slide cushioning. Each servo motor maintains the precision required for its specific function while both being utilized during different phases of the pressing cycle. This increases the overall utilization rate of the servo motor system without compromising the manufacturing precision of either cushioning function.
5Volume of stationary object
If the proportional valve releases oil flow to reduce servo motor capacity, then the servo motor size is reduced, but the oil flow serves as part of die cushion force causing pressure loss
Solution Approach 1:
The proportional valve is extracted from the hydraulic circuit and replaced with direct hydraulic connection. The servo motor directly drives the hydraulic pump that supplies pressure fluid to the cushioning cylinder, eliminating the intermediate proportional valve that was causing pressure loss. This ensures that the full oil flow generated by the hydraulic pump contributes to the cushioning force without being partially released through the proportional valve, thereby maintaining maximum die cushion force with a appropriately sized servo motor.
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
The solution reduces the size and cost of the servo motor, enhances energy efficiency, and improves the response time of the slide cushion force generation by using the servo motor in both die cushion and slide cushion functions, thereby increasing the value of the expensive servo motor.
Implementation Method 1
a hydraulic pump/motor that generates pressure fluid for driving the first fluid-pressure cylinder or the second fluid-pressure cylinder
Implementation Method 2
a servo motor that is connected to a rotating shaft of the fluid-pressure pump/motor
Data Source
AI summary
A die cushion-cum-slide cushion device selectively opens and closes a flow channel between a hydraulic pump/motor driven by a servo motor, and hydraulic cylinders that generate slide cushion force, or a flow channel between the hydraulic pump/motor, and hydraulic cylinders that generate die cushion force, by switching a selector valve. Before applying the slide cushion force is started, the servo motor is controlled to allow the hydraulic cylinders to generate required slide cushion force through a check valve. While the slide cushion force is applied, hydraulic circuits, each of which includes a logic valve, control pressure of the hydraulic cylinders, and hydraulic circuits, each of which includes the servo motor, control die cushion pressure of the hydraulic cylinders.