Hydraulic Forging Hammer Circuit for Ram Speed and Cavitation Control
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Solution Overview
Problem
Existing hydraulic forming machines, particularly forging hammers, face challenges in achieving precise movement control of the ram and are prone to cavitation in hydraulic circuits, including hydraulic working chambers, valves, and lines during operation.
Innovation Solution
A hydraulic forming machine with a hydraulic circuit that includes a valve with an adjustably variable volume flow and an actuator to control hydraulic fluid flow, allowing for precise movement control and minimizing cavitation by maintaining hydraulic pressure above the cavitation threshold during the working stroke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a hydraulic drive with pump and electrically controllable pump motor is used, then the forming machine can achieve high power and productivity, but the movement control precision of the ram and reproducibility of forming speed deteriorate
Solution Approach 1:
The patent replaces the traditional pump-driven hydraulic system with a hydraulic accumulator-driven system. The accumulator stores hydraulic energy under pressure and releases it controllably to drive the ram, eliminating the need for a pump and motor during the forming stroke. This substitution enables precise movement control through better hydraulic fluid management while maintaining high power delivery during the actual forming operation.
Solution Approach 2:
The hydraulic accumulator is pre-charged with hydraulic fluid under high pressure before the forming operation. This preliminary action stores the energy needed for the forming stroke, allowing the system to deliver high power when needed without requiring a pump to generate pressure during the actual forming process, thereby improving both power delivery and control precision.
2Device complexity
If a simple directional valve is used to control the hydraulic cylinder, then the device complexity is reduced, but cavitation occurs in the hydraulic circuit during operation
Solution Approach 1:
The patent extracts the cavitation problem from the system by implementing a dedicated suction valve that separates the fluid supply function from the directional control function. The suction valve ensures continuous fluid supply to the acceleration chamber, preventing cavitation, while the directional valve handles only the switching of hydraulic flow direction. This separation eliminates cavitation without significantly increasing overall system complexity.
Solution Approach 2:
The suction valve acts as an intermediary component between the hydraulic reservoir and the acceleration chamber. It mediates the fluid supply by ensuring continuous, cavitation-free delivery of hydraulic fluid to the acceleration chamber, thereby protecting the hydraulic circuit from cavitation damage while working in conjunction with the existing directional valve.
3Manufacturing precision
If the acceleration phase is extended to achieve precise setpoint speed, then the movement control precision is improved, but the productivity decreases due to longer cycle time
Solution Approach 1:
The patent implements periodic action by using the hydraulic accumulator to deliver a concentrated, high-power impulse during a brief forming stroke, followed by a rapid reset phase. This periodic operation allows for precise speed control during the forming stroke while maintaining high productivity through quick cycle completion. The accumulator enables the system to achieve the required setpoint speed precision without extending the overall cycle time.
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 enables improved movement control and significantly reduces cavitation, optimizing the forming process by maintaining hydraulic pressure above the cavitation threshold, thereby enhancing the reliability and efficiency of the forming machine.
Implementation Method 1
a hydraulic circuit (8) which is configured to adjust and vary a volume flow of a valve (12), depending on a setpoint speed (Vsoll) of the ram (2) to be achieved in an acceleration phase of a working stroke (A)
Implementation Method 2
the hydraulic pressure (p) prevailing in the first hydraulic working chamber (9) in the movement phase (B) following the acceleration phase (A)
Data Source
AI summary
The underlying invention relates particularly to a hydraulic forming machine, more particularly a forging hammer, for workpiece forming, comprising a hydraulic cylinder for driving a ram configured for workpiece forming, and a hydraulic circuit configured for operation of the hydraulic cylinder, wherein the hydraulic circuit has an actuator with an adjustably variable volume flow via which a first hydraulic working chamber of the hydraulic cylinder, used to accelerate the ram during the execution of a working stroke (A) for workpiece forming, can be provided with hydraulic fluid. The hydraulic circuit is configured to adjust and vary the volume flow of the valve or actuator, depending on a setpoint speed (Vsoll) of the ram to be achieved in an acceleration phase of a working stroke (A), and to optimize the subsequent movement phase.