Detailed description of numerical control hydraulic die forging hammer

5.1 Hydraulic principle of numerical control hydraulic die forging hammer
Numerical control hydraulic die hammer used pump - accumulator drive, the lower cavity of fuel tank is connected with normal pressure, hydraulic system controls upper cavity separately. Open filling valve (also known as hit valve), the high pressure oil from pump, accumulator and lower cavity through differential circuit, total of three parts enter into the upper cavity to achieve the hammer head fall acceleratively and hit stroke. Once the upper cavity release pressure, the hammer head return back rapidly. The precise control of hit energy is achieved by numeralization control, which is decided by the length of time of control valve closing.

After the main pump starts up, filling oil to the accumulator make hammer head lift up, the lower cavity of main fuel tank is connected with accumulator, which makes the hammer head to the upper limit, hammer is lifting status. When blowing down, through the control valve closing time to control the hit energy, make oil of lower cavity return back into the upper cavity, high-pressure oil of accumulator pump to achieve hitting. During hoisting hammer condition, control unloading valve of pressure sensor opened, pumps are no load running, pressure oil of accumulator kept pressure, which makes hammer head safe. System oil temperature doesn’t heat, energy is saving. The main hit valve’s reversing is high sensity and is good sealing characteristics. The whole is the overhead structure, the integrated assembly, without reducing the oil pipeline and high reliability.
The hydraulic system just control the upper chamber, through controlling the closing time of hit valve realizes the size of hit energy, hit valve is two stage control valve, first-level lead valve is a two-position three way directional control valve, the system requires high quality for it, should have high-frequency and also require high repeat accuracy.
Using top set structure, the internal oil route sealed on the main valve block, such structure caused the hydraulic system realized the integration, compare with oil tank adopted side set type, the piping system length reduce greatly, the energy loss reduced above 1 time, in addition through the integration, the oil route connection realized no tube connection, increased the connection reliability.
In the hydraulic system has established a safety valve between the accumulator and the bottom chamber, once hammer rod break from middle, cut-off the bottom chamber oil and accumulator immediately, thus enhanced the degree of security of operation.
The oil tank is top set type, the tank body is weldment, which uses the CO2 protection welding, conforms to JB/T5000.3-1998 and ZQ4000.3-86 "Welding General Specification Requirement" the concerned requirements, the tank body conforms to the JB/T5000.12-1998 concerned requirements after the surface treatment.
Flaw detection after the oil tank welding ceased the fat liquor leakage.
The oil tank uses enclosed type, can reduce the pollution
The hydraulic pressure station box body establishes reinforcement bar partly, causes the box body intensity to be high; The high-pressured oil route channel is unimpeded, the fat liquor resistance was small, heat gives off was few, enhanced the reliability

Liftout part
The Numerical Control hammer has liftout hydraulic station,the liftout installed in the die block,can choose the auto liftout and pedal liftout at will.
Cooling part
The main function of the cooling part is adjust the oil temperature,the cooling type have two kinds:plate type heat exchanger (water cooling)and electro cooling.。
Plate type heat exchanger(water cooling):
It mainly includes heat exchange pump group, plate type heat exchanger, water pump(user supply)、cooling tower(user supply)、water reservoir(user build)。Suck the hot oil of the oil return area of oil tank then sent to heat exchanger,heat exchange with the circulating water,back to suck area of oil tank after exchanger. The circulating water is cool water taken out from the bottom part of water reservoir by water pump(water temperature≤30℃)come into heat exchanger absorbed heat of hot oil then flow into cooling tower to cooling, flow into water reservoir after cooling.
The oil temperature better don't exceed 55℃ is a essential condition to ensure the system working normally. Therefore set oil-cooling system specially on the electro hydraulic hammer. The oil come to the plate type heat exchanger through hot oil pump, completes the heat exchange, when the system long time operation, exceed the temperature set of bimetallic thermometer discrete sampling, UC4-75 electric bell warning.
The feature of plate type heat exchanger is the heat transfer loss small, the thermal efficiency high, the structure is compact. But it must have sufficient water source and the cooling system.
Electro cooling
Electro cooling machine:Collect the cooling, heat and precision filter three large function
And has the remote control, filter chock warning functions and so on, thus guarantee the electro hydraulic forging hammer operated reliably.
Open the electro cooling machine(use NTC temperature sensor display the detection oil temperature on numeral display thermostat, and compare the detection oil temperature with the set temperature at the same time, if the oil temperature higher than the set value)start compressor.
Start cooling → condenser → expansion valve → evaporator (heat exchanger),hydraulic oil → oil tank → pump → evaporator(temperature depress)→ filter →oil tank. Circle like this till oil temperature reach set value. When the oil temperature lower than the lower limit of set ,controller start heater according to the signal send by temperature sensor.
Lubrication part
The self-lubrication device also can be adjusted by the customer, the adjustment is also the touch screen adjustment input, like how long the lubrication pump work. It can adjust by the user according to the actual situation.
Vibration isolation foundation part
The numerical control hammer foundation adopts Germany technical GERB vibration isolation device
The feature of the vibration isolation foundation:
(1)The size of base reduce more relative fixed support,leave out crossbar beam, fembedded part,saved the foundation cost and the construction time,maintenance facility。
(2)The vibration isolation effect is good,can reduce vibration 80-95%。
(3)The life high to 30-50 years,so no need rework.
(4)Simplify the leveling of machine,it can adjust when the foundation go down or incline.
(5)Reduce the vibration level of machine self and round equipment,reduced the failure rate of hydraulic press system and electro control system.
The compose of the vibration isolation device:
This system is composed of spring and stagnant damper
The function of spring is to supply elasticity cushion,reduce system natural frequency. It adopts helical spring, this spring bear high and elasticity large.
VISCO® stagnant damper have in the macroviscosity liquid cylinder body and a special shape plunger insert into liquid, the plunger do movement transform the mechanical energy into the heat energy in the liquid, this make the shock motion of forging hammer weaken to zero. Regarding attacks equipment, can absorb the impacting energy, make the equipment tends to be stable rapidly after the equipment was subject to the impact disturbance, guaranteed forging hammer's impact vibration completely steadily before next time hit, the forging hammer cannot have double hit resonating. Distance forging hammer 10, the ground oscillator measurement curve (sees following drawing)

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