A kind of low pressure thermal forming device
Technical field
The present invention relates to machinery production field, particularly to a kind of low pressure thermal forming device.
Background technology
The composite bending modulus high due to hollow section component and modulus of rigidity are it is considered to be realize structure lightened optimal knot
Configuration formula.It is widely used in the industries such as Aeronautics and Astronautics, automobile and bicycle.Fluid internal pressure shapes the elder generation being to process this class A of geometric unitA
Enter forming technique.The know-why that fluid internal pressure shapes is initial blank inside to apply high pressure medium make blank cross section week
Length increases and shapes the hollow member of different cross section form.The essence of its deformation is parison swell deformation.But this kind of distorted pattern
Formula has limitation, it is impossible to or the shaping of plasticity relatively low material higher for intensity, and its reason shows as following several respects:
One, for needing the material of phase transformation strengthening cannot realize heat treatment in forming process.
Two, in order uniquely to deform, to be only possible to order about tubing when driving force, only pressure reach the highest complete due to intrinsic pressure
Shape, it is therefore necessary to be equipped with special high-power supercharger, simultaneously by superhigh pressure sealing technical limitations, form high strength or low mould
During property material hollow unit, difficulty is the biggest.Additionally, for providing enough mold clamping force, it is necessary to use large-tonnage equipment.The problems referred to above
Significantly hinder the engineer applied of this technology.
Its three, mainly produce required odd-shaped cross section by dilatancy owing to fluid internal pressure shapes, and expand change
Shape pattern belongs to double tensile stress state, for the material that plasticity is relatively low, easily ruptures, this skill when thus be accordingly used in Al alloys andMg alloys
There is the biggest defect in art.
Its four, the most relatively low for its elastic modelling quantity of Materials with High Strength, during shaping, elastic return is violent, and room temperature fluid internal pressure becomes
The form accuracy of shape it is difficult to ensure that.
There is scholar to propose hot interior pressing formation, although the method solves the problem of forming limit, but exacerbate wall thickness not
Equal problem, and the restriction of heated medium supercharger and the restriction of gases at high pressure safety problem, be unsuitable for engineer applied.
For these reasons, transfer being bent into primary deformable pattern to, change fluid internal pressure and shape to be expanded to uniquely become
The drawback of shape pattern, and make full use of the intrinsic pressure rising certainly that member section change in high temperature volumetric expansion and forming process causes
Characteristic provides driving force for deformation, it is to avoid under traditional handicraft depend on supercharger unduly, drip molding springback capacity is big, form accuracy
The problem that low and evenness of wall thickness is poor, reduces technology difficulty, widens the technique scope of application, and improving forming quality is the former of the present invention
Power.
Summary of the invention
The purpose of the present invention is aiming at the drawbacks described above that prior art exists, it is provided that a kind of low pressure thermal forming device, its
When mainly solving existing apparatus and process forming high intensity or inductile hollow unit, resistance of deformation is big, drip molding uniform wall thickness
Property difference and d type precision the highest, easily rupture, efficiency is low with the problem that cannot synchronize to carry out heat treatment.
A kind of low pressure thermal forming device that the present invention mentions, its technical scheme is: include left electrode (2), left sealing punch
(3), mold (15), right electrode (16), right sealing punch (17) and lower mold (21), described mold (15) and upper work
Platform (11) connects, and lower mold (21) is connected with lower table (1);Left sealing punch (3) is by Filled Dielectrics passage (5) and cooling
Medium switch (4) is connected with outside cooling medium source (6), simultaneously by check valve (7), air relief valve (8) and air inlet switch (10)
It is connected with extraneous gas medium source (9);Right sealing punch (17) has pressure release passage (19) and is connected with relief valve (18);Left electricity
Pole (2) and right electrode (16) are connected with power supply (14) by wire (12) and on and off switch (13);
By left sealing punch (3) and right sealing punch (17) to initial pipe (20) end seal, and move on to specify position;Left
Electrode (2) moves to right electrode (16) contact with initial pipe (20), and left electrode (2) is arranged on the right side of left sealing punch (3)
Side, and right electrode (16) is arranged on the left side of right sealing punch (17);
The section girth of described initial pipe (20) is equal to 0.5-1.5 times of whole drip molding perimeter of section;
Described on and off switch (13) Guan Bi, and quickly the pipe entirety sealing energising is moved in the die cavity of lower mold (21),
Wherein, traveling time is less than 60 seconds.
A kind of hot formed method of low pressure that the present invention mentions, comprises the following steps:
Step one: mould prepares, first designs corresponding left electrode (2), left sealing punch (3), mold according to Components Shape
(15), right electrode (16), right sealing punch (17) and lower mold (21), described mold (15) and upper table (11) are even
Connecing, lower mold (21) is connected with lower table (1);Left sealing punch (3) is switched by Filled Dielectrics passage (5) and cooling medium
(4) it is connected with outside cooling medium source (6), simultaneously by check valve (7), air relief valve (8) and air inlet switch (10) and outside gas
Body medium source (9) connects;Right sealing punch (17) has pressure release passage (19) and is connected with relief valve (18);Left electrode (2) and
Right electrode (16) is connected with power supply (14) by wire (12) and on and off switch (13);
Step 2: initial pipe prepares, selects the suitably initial pipe of size, and wherein, the section girth of initial pipe is equal to
0.5-1.5 times of whole drip molding perimeter of section, and initial pipe length is more than part length;
Step 3: blank end is sealed by left sealing punch (3) and right sealing punch (17), moves on to specify position the most together;
Step 4: left electrode (2) moves to contact with initial pipe with right electrode (16), wherein, left electrode is arranged on left sealing and rushes
The right side of head, and right electrode is arranged on the left side of right sealing punch;
Step 5: adjust air relief valve (8), pressure is reduced to concrete technology desired value, then opens air inlet switch (10) to pipe
Internal ventilation body medium;
Step 6: on and off switch (13) closes, moves to the pipe entirety sealing energising in the die cavity of lower mold (21), and mobile
Time is less than 60 seconds;
Step 7: mold (15) is descending, compression pipe brings it about flexural deformation, and pipe sectional area reduces therewith, internal pressure
Power raises further, promotes pipe to shape further, whole during control air pressure inside by relief valve (18), until mould
Guan Bi;
Step 8: pressurize, continues to pipe to shape;
Step 9: on and off switch (13) disconnects, opens cooling medium switch (4), and to the internal logical cooling medium of pipe, pressure increases to
Relief valve is opened, and gas flow and ventilation duration meet drip molding cooling technological requirement simultaneously;
Step 10: close cooling medium switch (4), left sealing punch (3), right sealing punch (17), left electrode (2) and right electrode
(16) retreat to not affecting drip molding taking-up, open mould, take out drip molding (22).
Preferably, in above-mentioned step 5, reducing to 0 ~ 50MPa for Materials with High Strength pressure, inductile material pressure reduces to 0
~40MPa。
Preferably, above-mentioned power supply is pulse current power supply.
Preferably, the specific bit in step 3 is set to lower mold (21) or is easy to connect electrode zone.
Preferably, above-mentioned initial pipe (20) uses high-strength material or inductile material.
Preferably, above-mentioned cooling medium source (6) is cryogenic gas or liquid;Gas medium is room temperature air or low wet
Body.
The invention has the beneficial effects as follows:
One, makes full use of the intrinsic pressure increase that temperature own in technical process raises and change in volume causes and drives as deformation
Power, it is not necessary to optional equipment supercharger, technique is simple, low cost;
Its two, use and there is the cooling medium of certain pressure directly in mold cavity, component quenched, advantageously ensure that
The geometric accuracy of drip molding, and improve process efficiency;
Its three, owing to the deformation pattern of this technique is based on flexural deformation, it is to avoid the unfavorable shadow that under high temperature, hardenability value reduces
Ringing, drip molding evenness of wall thickness is good, and the technique suitability is strong;
Its four, quenched in hollow section member cavity by cooling medium, owing to medium directly contacts with component, cooling
Speed is fast and uniform, and performance is the best;
Its five, under hot forming, elastic deformation is extremely low, and drip molding is easily guaranteed that almost without resilience, drip molding form accuracy;
Its six, by large power supply directly to heating of pipe blank, speed is fast, and thermal losses is low, overcomes traditional hot fluid internal pressure
Forming efficiency is low, it is impossible to the shortcoming meeting engineer applied;
The present invention is reasonable in design, reliable operation, effect notable, has stronger promotional value.
Accompanying drawing explanation
Fig. 1 is the structural representation of the mould of the present invention;
Fig. 2 is the A-A structure chart of the mould of the present invention;
Fig. 3 is mould matched moulds and quenching principle schematic diagram;
Fig. 4 is the B-B structure chart of Fig. 3;
In upper figure: lower table 1, left electrode 2, left sealing punch 3, cooling medium switch 4, Filled Dielectrics passage 5, cooling medium
Source 6, check valve 7, air relief valve 8, gas medium source 9, air inlet switch 10, upper table 11, wire 12, on and off switch 13, power supply
14, mold 15, right electrode 16, right sealing punch 17, relief valve 18, pressure release passage 19, initial pipe 20, lower mold 21, one-tenth
Shape part 22.
Detailed description of the invention
1-2 referring to the drawings, the invention will be further described:
A kind of low pressure thermal forming device that the present invention mentions, including left electrode 2, left sealing punch 3, mold 15, right electrode 16,
Right sealing punch 17 and lower mold 21, is characterized in that: described mold 15 is connected with upper table 11, lower mold 21 and lower work
Station 1 connects;Left sealing punch 3 is connected with outside cooling medium source 6 by Filled Dielectrics passage 5 and cooling medium switch 4, with
Time be connected with extraneous gas medium source 9 by check valve 7, air relief valve 8 and air inlet switch 10;Right sealing punch 17 has pressure release and leads to
Road 19 is also connected with relief valve 18;Left electrode 2 and right electrode 16 are connected with power supply 14 by wire 12 and on and off switch 13;
By left sealing punch 3 and right sealing punch 17 to initial pipe 20 end seal, and move on to specify position;Left electrode 2
Move to right electrode 16 contact with initial pipe 20, and left electrode 2 is arranged on the right side of left sealing punch 3, and right electrode 16 sets
Put the left side at right sealing punch 17.
The section girth of above-mentioned initial pipe 20 is equal to 0.5-1.5 times of whole drip molding perimeter of section.
Above-mentioned on and off switch 13 closes, and quickly the pipe entirety sealing energising is moved in the die cavity of lower mold 21,
Wherein, traveling time is less than 60 seconds.
It is descending that above-mentioned mold 15 presses setting curve, and compression pipe brings it about flexural deformation, and pipe sectional area is therewith
Reduce, internal pressure raise, promote pipe to shape, whole during pass through relief valve 18 control air pressure inside.
Referring to the drawings 3-4, a kind of high intensity that the present invention mentions or the inductile material hot formed side of hollow unit low pressure
Method, comprises the following steps:
Step one: mould prepares, first designs corresponding left electrode 2, left sealing punch 3, mold 15, the right side according to Components Shape
Electrode 16, right sealing punch 17 and lower mold 21, above-mentioned same as the prior art, this does not repeats.Mold 15 and upper table
11 connect, and lower mold 21 is connected with lower table 1.Left sealing punch 3 by Filled Dielectrics passage 5 and cooling medium switch 4 with
Outside cooling medium source 6 connects, and is connected with extraneous gas medium source 9 by check valve 7, air relief valve 8 and air inlet switch 10 simultaneously.
Right sealing punch 17 has pressure release passage 19 and is connected with relief valve 18.Left electrode 2 and right electrode 16 are by wire 12 and power supply
Switch 13 is connected with power supply 14.
Step 2: initial pipe prepares, selects the suitably initial pipe of size, and its main points are the cross section week of initial pipe
The section girth of long and whole drip molding is close, and the section girth of general initial pipe should be equal to drip molding perimeter of section at end
0.5-1.5 times.Initial pipe length should be greater than part length, it is ensured that has enough sealing areas and electrode contact region.
Step 3: blank end is sealed by left sealing punch 3 and right sealing punch 17, moves on to specify position the most together.
Sealing means is same as the prior art, and this does not repeats.
Step 4: left electrode 2 moves to contact with pipe with right electrode 16, its main points are that left electrode should be at left sealing punch
Right side, and right electrode i.e. should ensure in the left side of right sealing punchl a It is less thanl b 。
Step 5: adjust air relief valve 8, pressure is reduced to concrete technology desired value, then opens air inlet switch 10 to pipe
Internal ventilation body medium.Its main points are for typically to reduce to 0 ~ 50MPa for Materials with High Strength pressure, and inductile material pressure typically reduces to
0~40MPa。
Step 6: on and off switch 13 closes, and quickly the pipe entirety sealing energising is moved in the die cavity of lower mold 21,
Its main points are that traveling time is less than 60 seconds.Along with the carrying out of energising, blank temperature constantly raises, under the flow stress of material
Fall, elongation percentage improves, and pipe internal gas expanded by heating simultaneously, air pressure constantly raises.
Step 7: it is descending that mold 15 presses technique initialization curve, compression pipe brings it about flexural deformation, pipe sectional area
Reducing therewith, internal pressure raises further, promotes pipe to shape further, whole during control inside by relief valve 18
Air pressure maximum is in concrete technology claimed range, until mould Guan Bi.
Step 8: pressurize certain time, its main points are that pressurize continues to pipe to shape.
Step 9: on and off switch 13 disconnects, opens cooling medium switch 4, to the internal logical cooling medium of pipe, and continues one
Fixing time, its main points are that pressure increases to relief valve unlatching also, and gas flow and ventilation duration meet drip molding cooling technique simultaneously
Requirement.
Step 10: close cooling medium switch 4, after left sealing punch 3, right sealing punch 17, left electrode 2 and right electrode 16
Retreat to not affect drip molding take out, open mould, take out drip molding 22.
Wherein, the power supply that the present invention mentions is large power supply, and large power supply is current range 0-5000000A, voltage
The power supply of scope 0-36V, power supply is pulse current power supply, pulse frequency 0-10000Hz, amplitude 0-100000A, voltage range 0-
The power supply of 100000V.
Specific bit in step 3 be set to lower mold 21 or just be connected electrode zone;Specific bit in step 3 is set to down
The interior die cavity of mould 21;Specific bit in step 3 is set to be easy to connect electrode zone;
The high-strength material of initial pipe employing or inductile material, high-strength material is high-strength steel or titanium alloy, and high-strength steel is
22MnB5, titanium alloy is TC4;Inductile material is aluminium alloy or magnesium alloy, aluminium alloy be 2000 be, 5000 be 6000 be or
7000 line aluminium alloys;
Cooling medium is cryogenic gas or liquid, and gas medium is room temperature air or cryogenic gas, and gas medium is cryogenic gas.