Die Cushion Apparatus Torque Control and Energy Regeneration
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Solution Overview
Problem
Existing die cushion apparatuses for press machines face issues such as energy inefficiency, increased impact forces leading to structural damage, difficulty in maintaining pressure at bottom dead center, and lack of regenerative energy recovery, particularly in hydraulic and electric servo types.
Innovation Solution
A die cushion apparatus incorporating a hydraulic cylinder, pressure detector, hydraulic pump/motor, electric motor, and regeneration device that directly connects the discharge opening to the pressure chamber, allowing for torque control of the electric motor to manage die cushion pressure efficiently and regenerate energy as electrical energy, reducing heat generation and enabling miniaturization and cost reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a pneumatic die cushion apparatus is used, then surge pressure does not occur, but the apparatus size increases and additional mechanisms are required
Solution Approach 1:
The patent replaces the pneumatic system with a direct electric motor-driven mechanism. The electric motor directly drives the cushion pad through a screw mechanism, eliminating the need for compressible fluid systems while maintaining surge pressure control. This substitution reduces apparatus size by removing pneumatic cylinders, reservoirs, and associated piping.
2Stress or pressure
If an oil hydraulic die cushion apparatus is used, then surge pressure can be controlled, but energy is converted to heat and cooling function is required
Solution Approach 1:
The patent replaces the oil hydraulic system with a direct electric motor-driven screw mechanism. This eliminates the need for hydraulic fluid circulation and pressure control systems that generate heat. The electric motor provides direct mechanical drive without energy loss to heat, removing the requirement for cooling apparatus.
3Ease of operation
If an electric servo die cushion apparatus with screw and nut mechanism is used, then pressing force control is facilitated, but the mechanism size increases
Solution Approach 1:
The patent extracts and eliminates the screw and nut mechanism from the system. Instead of using a mechanical screw drive, the invention employs a direct electric motor connection to the cushion pad. This extraction removes the bulky mechanical transmission components while maintaining precise pressing force control through electric motor torque regulation.
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 provides excellent energy efficiency, responsiveness to die cushion pressure commands, and improved controllability at bottom dead center, minimizing surge pressure and heat generation while enabling significant miniaturization and cost reduction.
Implementation Method 1
a discharge opening is connected via a first pipe to a pressure chamber on a cushion pressure production side of the fluid hydraulic cylinder; a fluid hydraulic pump/motor
Implementation Method 2
an electric motor that is connected to a rotating shaft of the fluid hydraulic pump/motor; a control device that controls a torque of the electric motor
Implementation Method 3
a pressure detector that detects a pressure of a pressure chamber on a cushion pressure production side of the fluid hydraulic cylinder
Implementation Method 4
a regeneration device that regenerates energy required for a die cushioning action as electrical energy
Data Source
AI summary
A die cushion apparatus of a press machine in which a discharge opening of a fluid hydraulic pump/motor is directly connected to a pressure chamber on a cushion pressure production side of a fluid hydraulic cylinder and the torque of a rotating shaft of the fluid hydraulic pump/motor is controlled by an electric motor to control a pressure (die cushion pressure) of the pressure chamber on the cushion pressure production side. It is therefore possible to control the die cushion pressure with excellent responsiveness with respect to a die cushion pressure command and prevent occurrence of a surge pressure. The die cushion apparatus also has excellent energy efficiency since energy required for a die cushioning action that a cushion pad receives when effecting die cushioning of a press machine is regenerated as electrical energy through the fluid hydraulic cylinder, fluid hydraulic pump/motor, and electric motor.