CN104001781A - Forming device and method for high-precision hollow component - Google Patents

Abstract

The invention relates to a forming device and method for a hollow member with a precise rectangular cross-section. The method of the invention is as follows: Step 1: Prepare a mold, add an anti-deformation structure on the mold, and install a check valve on the punch; Step 2: Put the initial tube blank Enter the mold cavity, close the mold, and seal the end; step 3 fill the fluid medium into the tube blank; step 4 anti-deformation mechanism moves in opposite directions to form a miniature petal shape; step 5 anti-deformation structure returns to the initial position, and the petal shape is sunken Flatten the part; repeat steps 4 and 5 to form the desired shape; remove the internal fluid pressure, open the mold, and take out the parts. By setting the anti-deformation mechanism in the mold, the repeated and cumulative utilization of the petal shape is realized. While eliminating the constant rolling effect of friction, the forming pressure is reduced, the occurrence of cracking defects is avoided, and the uniformity of wall thickness is improved to meet aerospace requirements. And other fields have high precision requirements for such components in terms of dimension accuracy and wall thickness uniformity.

Description

A high-precision hollow component forming device and method

technical field

The invention relates to the field of mechanical manufacturing, in particular to a high-precision hollow member forming device and method.

Background technique

At present, the rectangular section hollow member is an ideal load-bearing structure form. For bending and torsional loads, the rectangular section hollow member has the least failure mode, which can effectively balance the strength and stability failure problems, and then obtain the maximum ultimate bending and shear resistance. Bearing capacity, therefore, hollow members with rectangular cross-sections are important structural forms of aviation, aerospace and automotive equipment.

In the current manufacturing process of rectangular cross-section hollow members, it is generally formed by stamping-welding and direct forming by internal high pressure. The first method introduces two longitudinal welds, which destroys the integrity of the structure and causes welding thermal deformation; The second method requires extremely high forming pressure, resulting in stress concentration at the transition between the straight edge area and the rounded corner area, and the wall thickness is severely thinned or even cracked. The shape and precision of such components affect the penetration capability of aviation equipment. Strike precision and aerodynamic performance, especially fatigue performance.

In order to avoid being restricted by the forming pressure and improve the uniformity of the wall thickness, some scholars have proposed to improve the forming ability of the fillet by preforming the petals. It is not big, and because the shape of the petals is realized by preforming, a special preforming process is required, especially the shape of the petals only works in the initial stage of forming, because the effect of reducing the shaping pressure is only before the cross-sectional shape of the petals disappears, Therefore, the required petal features are generally more obvious, and the amount of reverse deformation is relatively large, which in turn weakens the effect of plastic thrust.

Contents of the invention

The object of the present invention is to address the above-mentioned defects in the prior art, and provide a high-precision hollow member forming device and method. By setting an anti-deformation mechanism in the mold, the repeated and cumulative utilization of the petal shape can be realized, and the fixed friction can be eliminated. At the same time, the rolling action reduces the forming pressure, avoids the occurrence of cracking defects, and improves the uniformity of wall thickness, so as to meet the high-precision requirements for dimension accuracy and wall thickness uniformity of such components in aerospace and other fields.

A method for forming a high-precision hollow member, the technical solution of which is to include the following steps:

Step 1: Mold preparation. First, design the lower mold, upper mold, left punch and right punch according to the shape of the component. The upper and lower molds are respectively connected to the worktable and upper slider of the press, and the punch is provided with a medium injection hole. , and connected to a high pressure source through a one-way valve;

Step 2: Install an anti-deformation mechanism on the mold. One end of the anti-deformation mechanism faces the mold cavity, and the other end extends out of the mold cavity, and can realize feeding and retreating along the required direction;

Step 3: Prepare the initial tube blank, select the initial tube blank with a suitable size, the main point is that the cross-sectional perimeter of the initial tube blank is similar to the cross-sectional perimeter of the final formed part, and generally the cross-sectional perimeter of the initial tube blank should be equal to the final shape. 0.7-1.2 times the perimeter of the section of the shape;

Step 4: Put the initial tube blank into the mold cavity, close the mold, feed the punch axially to the end of the tube blank for sealing, and apply the mold clamping force;

Step 5: Fill the tube blank with liquid medium from the medium filling hole until the cavity of the tube blank is full;

Step 6: The anti-deformation mechanism moves toward the inside of the mold cavity, a small depression is formed on the straight wall of the tube blank, the internal liquid volume is continuously compressed, the liquid pressure rises, and the material fills and forms the fillet;

Step 7: The anti-deformation mechanism gradually retreats to the initial position, and then increases the internal liquid pressure. Under the action of the liquid pressure, the depression on the straight wall is continuously flattened, forming a horizontal thrust along the tangential direction. At the same time, due to the existence of the depression, the tube blank No contact with the mold, eliminating the pinning effect of friction, the material is easily pushed to the fillet area, and the fillet is further reduced;

Step 8: Repeat steps 6 and 7 until the final shape is reached;

Step 9: Open the one-way valve, remove the internal liquid, move the punch back until the formed part can be easily taken out, open the mold, and take out the formed part.

The above-mentioned lower mold is connected with the lower workbench of the press, the upper mold is connected with the upper slider of the press, and a check valve is installed between the left punch and the high pressure source.

The width a ₁ of the anti-deformation mechanism is 0.1 a ~ 0.3 a , the b ₁ is 0.1 b ~ 0.3 b , the length l ₁ is 0.9 l ~ 1.0 l , and can move forward and backward with the ejector mechanism.

The anti-deformation mechanism moves toward the inside of the mold cavity, and the straight wall of the tube blank forms a small depression, and the cross-sectional shape of the tube blank becomes a micro-petal shape. Filling, the radius of the fillet is continuously reduced and gradually formed, wherein the reduction amount of the anti-deformation mechanism 9 and the anti-deformation mechanism 13 is 0.01a-0.3a, and the reduction amount of the anti-deformation mechanism 11 and the anti-deformation mechanism 15 is 0.01b -0.3b.

The high-precision hollow member forming device mentioned in the present invention includes a lower table, a lower mold, a medium filling hole, a left punch, an upper mold, an upper slider, a right punch, four ejection mechanisms, and four anti-deformation Mechanism, high pressure source, one-way valve, the lower mold is connected with the lower workbench of the press, the upper mold is connected with the upper slider of the press, a one-way valve is installed between the left punch and the high-pressure source, and four One anti-deformation mechanism, one end of the four anti-deformation mechanisms faces the mold cavity in the middle, and the other end extends out of the mold cavity, and is connected with the four ejection mechanisms of the press; the left punch and the right punch advance in the axial direction To seal the end of the tube blank, apply mold clamping force.

The above-mentioned anti-deformation mechanism has a width a ₁ of about 0.1 a to 0.3 a , b ₁ of about 0.1 b to 0.3 b , and a length l ₁ of 0.9 l to 1.0 l .

The present invention compares with prior art, and its beneficial effect is:

(1) The miniature petal shape can generate great horizontal thrust, which greatly reduces the fillet shaping pressure and breaks the production status of such parts overly dependent on the nominal capacity of the supercharger;

(2) The shape of the miniature petals can generate a huge horizontal thrust, so that the component is in a state of circumferential compressive stress. This stress state avoids the common cracking defects in the prior art, and the formed part has a dense structure and improved mechanical properties;

(3) The miniature petal shape is repeatedly formed and flattened during the entire forming process, so that the deformed part of the blank and the inner surface of the mold are always in a virtual contact state, which eliminates the inhibition of the friction force on the metal flow and improves the uniformity of deformation. The uniformity of the wall thickness of the part is guaranteed, and the damage to the surface quality of the formed part is small;

(4) The formed part is formed under the alternating action of positive deformation and reverse deformation, which can make full use of the Bauschinger effect of the material, suppress the springback of the component, and the dimensional accuracy of the formed part is extremely high;

(5) The straight wall part of the tube blank is always in a state of uniform compressive stress along the thickness direction, which can ensure that this part participates in plastic deformation from the beginning to the end, coordinates the uniformity of metal flow, and further ensures the uniformity of the wall thickness of the formed part.

(6) Since the micro-petal shape is realized by the anti-deformation mechanism, no pre-forming process is required, and the optimal micro-petal shape required for different deformation stages can be flexibly realized by controlling the amount of anti-deformation;

The invention is reasonable in design, reliable in operation, remarkable in effect and has strong popularization value.

Description of drawings

Accompanying drawing 1 is the structural representation of forming device of the present invention;

Accompanying drawing 2 is the A-A structural diagram of forming device of the present invention;

Accompanying drawing 3 is the schematic diagram of deformation situation after mold clamping and applying end seal;

Accompanying drawing 4 is the B-B structure schematic diagram of Fig. 3;

Accompanying drawing 5 is to fill liquid medium and then form internal pressure schematic diagram;

Accompanying drawing 6 is the B-B structure schematic diagram of Fig. 5;

Accompanying drawing 7 is the schematic diagram that anti-deformation mechanism promotes micro-petal shape;

Accompanying drawing 8 is the schematic diagram that anti-deformation mechanism retreats completely;

Accompanying drawing 9 is a schematic diagram of raising the pressure until the micro-petal shape disappears;

Accompanying drawing 10 is the schematic diagram of mold opening situation;

Accompanying drawing 11 is the B-B structural diagram of Fig. 10;

In the picture above: lower table 1, lower mold 2, medium filling hole 3, left punch 4, upper mold 5, upper slider 6, right punch 7, ejection mechanism 8, 10, 12, 14, anti-deformation Mechanisms 9, 11, 13, 15, high pressure source 16, check valve 17.

Detailed ways

A method for forming a high-precision hollow member, the technical solution of which is to include the following steps:

Step 1: Die preparation, first design the corresponding lower die 2, upper die 5, left punch 4 and right punch 7 according to the shape of the component, the above is the same as the prior art, and will not be repeated here. The lower mold 2 is connected to the lower workbench 1 of the press, the upper mold 5 is connected to the upper slider 6 of the press, and a check valve 17 is installed between the left punch 4 and the high pressure source 16;

Step 2: Set the anti-deformation mechanism 9, 11, 13, 15 on the mold, one end of the anti-deformation mechanism faces the mold cavity, and the other end extends out of the mold cavity, and is connected with the ejection mechanism 8, 10, 12, 14 of the press . The main point is that the width a ₁ of the anti-deformation mechanism is about 0.1 a ~ 0.3 a , b ₁ is about 0.1 b ~ 0.3 b , and the length l ₁ is 0.9 l ~ 1.0 l . And it can move forward and backward with the ejector mechanism;

Step 3: Initial tube blank, select the initial tube blank with appropriate size, the main point is that the cross-sectional perimeter of the initial tube blank is similar to the cross-sectional perimeter of the final forming part, generally the cross-sectional perimeter of the initial tube blank should be equal to the final forming 0.7-1.2 times the perimeter of the section;

Step 4: Put the initial tube blank into the mold cavity, close the mold, feed the left punch 4 and right punch 7 to the end of the tube blank in the axial direction to seal, and apply the mold clamping force;

Step 5: Fill the tube blank with liquid medium from the medium filling hole 3 until the cavity in the tube blank is full;

Step 6: The anti-deformation mechanism 9, 11, 13, 15 moves toward the inside of the mold cavity, a small depression is formed on the straight wall of the tube blank, and the cross-sectional shape of the tube blank becomes a micro-petal shape. At the same time, due to the continuous compression of the internal liquid volume, When the liquid pressure rises, the material fills the fillet, and the radius of the fillet decreases continuously and forms gradually. The lower amount is 0.01b-0.3b;

Step 7: The anti-deformation mechanism 9, 11, 13, 15 gradually retreats to the initial position, and the internal liquid pressure is increased. Under the action of the liquid pressure, the depression on the straight wall is continuously flattened, and at the same time, due to the tangential formation of the liquid pressure, Horizontal thrust, the metal material is further pushed to the fillet area;

Step 8: Repeat step 6 and step 7 until the required fillet size is reached to form the required cross-sectional shape of the component;

Step 9: Open the one-way valve 17, remove the internal liquid, retreat the left punch 4 and the right punch 7 so that the removal of the formed part is not affected, open the mold, and take out the part.

In addition, the above-mentioned tube blank material is aluminum alloy, magnesium alloy, stainless steel, high-strength steel or titanium alloy, and the forming medium can be water, emulsion, pressure-resistant oil or gas.

Claims (6)

1. a manufacturing process for high accuracy hollow unit, is characterized in that comprising the following steps realization:

Step 1: mould is prepared, first need to design bed die, mold, left drift and right drift according to Components Shape, upper and lower mould is connected with workbench and the top shoe of forcing press respectively, and drift is offered medium hand-hole, and is connected with high-voltage power supply by check valve;

Step 2: Anti-deformation mechanism is set on mould, and Anti-deformation mechanism one end is towards mold cavity, and mold cavity is stretched out in one end, and can realize along needing sending to and retreating of direction;

Step 3: initial pipe is prepared, the initial pipe that preferred dimension is suitable, the section girth that its main points are initial pipe is close with the section girth of whole drip molding, and the section girth of general initial pipe should equal 0.7-1.2 times of whole drip molding perimeter of section;

Step 4: initial pipe is put into mold cavity, matched moulds, drift is fed to pipe end part seal vertically, applies mold clamping force;

Step 5: inner filling liquid medium to pipe die cavity is full of from Filled Dielectrics hole to pipe;

Step 6: Anti-deformation mechanism does subtend towards mold cavity inside and moves, pipe Zhi Bi position forms small depression, and internal liquid volume is constantly compressed, and fluid pressure raises, and material is filled to shape to fillet position;

Step 7: Anti-deformation mechanism is progressively retreating to initial position, then internal liquid pressure raises, under fluid pressure effect, the depression at Zhi Bi position constantly flattens, form horizontal thrust tangentially, simultaneously because the pipe that exists of depression does not contact with mould, eliminated the pinning effect of friction, material is very easy to be pushed to radius area, and fillet further reduces;

Step 8: repeating step six and step 7, until reach whole drip molding shape;

Step 9: open check valve, lay down internal liquid, drift retreats to drip molding and can conveniently take out, and opens mould, takes out drip molding.

2. the manufacturing process of high accuracy hollow unit according to claim 1, is characterized in that: described bed die is connected with the lower table of forcing press, and mold is connected with the top shoe of forcing press, between left drift and high-voltage power supply, installs check valve additional.

3. the manufacturing process of high accuracy hollow unit according to claim 1, is characterized in that: the width of Anti-deformation mechanism a ₁be 0.1 a~ 0.3 a, b ₁be 0.1 b~ 0.3 b, length l ₁be 0.9 l~ 1.0 l, and can be with the ejecting mechanism action that moves forward and backward.

4. the manufacturing process of high accuracy hollow unit according to claim 1, it is characterized in that: Anti-deformation mechanism moves towards the inner subtend of mold cavity, pipe Zhi Bi position forms small depression, pipe cross sectional shape becomes micro-petal shape, simultaneously because internal liquid volume is constantly compressed, fluid pressure raises, material is filled to fillet position, radius of corner constantly reduces and is shaped gradually, wherein, the drafts of Anti-deformation mechanism 9 and Anti-deformation mechanism 13 is 0.01a-0.3a, and the drafts of Anti-deformation mechanism 11 and Anti-deformation mechanism 15 is 0.01b-0.3b.

5. the building mortion of a high accuracy hollow unit, it is characterized in that: comprise lower table (1), bed die (2), Filled Dielectrics hole (3), left drift (4), mold (5), top shoe (6), right drift (7), four ejecting mechanisms, four Anti-deformation mechanisms, high-voltage power supply (16), check valve (17), bed die (2) is connected with the lower table (1) of forcing press, mold (5) is connected with the top shoe (6) of forcing press, between left drift (4) and high-voltage power supply (16), install check valve (17) additional, four Anti-deformation mechanisms are set on mould, one end of four Anti-deformation mechanisms is towards middle mold cavity, the other end stretches out mold cavity, and be connected with four ejecting mechanisms of forcing press, left drift (4) and right drift (7) are fed to pipe end part seal vertically, apply mold clamping force.

6. the building mortion of high accuracy hollow unit according to claim 5, is characterized in that: the width of described Anti-deformation mechanism a ₁be about 0.1 a~ 0.3 a, bbe about 0.1 b~ 0.3 b, length l ₁be 0.9 l~ 1.0 l.