A method and device for expanding special-shaped pipe fittings

Abstract

The present invention discloses a method and device for bulging special-shaped pipe fittings, the method comprising the following steps: step 1, placing a tube blank into a forming die; step 2, respectively sealing the upper and lower openings of the tube blank with upper and lower sealing modules to form a sealed cavity; step 3, applying pressure F to the top of the tube blank to drive the tube blank to move downward, and at the same time inflating or filling the sealed cavity, the internal pressure of the tube blank increases, and the pressure F and the internal pressure of the tube blank are alternately increased until the tube blank fits the cavity in the forming die, and the forming is completed to form a circular thin-walled tubular workpiece; step 4, after the pressure is released, the upper and lower sealing modules are disassembled to remove the circular thin-walled tubular workpiece. The present invention can improve the forming accuracy and processing quality.

Description

Technical Field

[0001] The invention relates to the technical field of forming devices, and in particular to a method and a device for expanding a special-shaped pipe fitting. Background Art

[0002] The main forming method of special-shaped pipe fittings with crests is to expand the high-strength steel tube billet to make it into a crest arc-shaped special-shaped pipe fitting. The existing technology mainly adopts two methods: mechanical forming and bulging forming. Among them, the crest formed by mechanical forming is very easy to crack and has a high defective rate; the crest formed by bulging forming, especially hydraulic forming, is a sharp corner, and the dimensional accuracy of the special-shaped pipe fittings is very low, which cannot meet the processing requirements. Therefore, it is necessary to develop a method that can ensure that the crest becomes an arc shape without cracking and has high precision. Summary of the invention

[0003] The purpose of the present invention is to provide a method for expanding a special-shaped pipe fitting in view of the problem that the wave peaks formed by processing the special-shaped pipe fitting in the prior art do not meet the demand.

[0004] Another object of the present invention is to provide a device for expanding special-shaped pipe fittings.

[0005] The technical solution adopted to achieve the purpose of the present invention is:

[0006] A method for expanding a special-shaped pipe fitting comprises the following steps:

[0007] Step 1, placing the tube blank into the forming mold;

[0008] Step 2, using upper and lower sealing modules to seal the upper and lower openings of the tube blank respectively to form a sealed cavity;

[0009] Step 3, applying pressure F to the top of the tube blank to drive the tube blank to move downward, and at the same time filling the sealed cavity with air or liquid, the internal pressure of the tube blank increases, and the pressure F and the internal pressure of the tube blank are alternately increased until the tube blank fits the cavity in the forming mold, and the forming is completed to form a round thin-walled tubular workpiece;

[0010] Step 4: After the pressure is released, disassemble the upper and lower sealing modules and remove the circular thin-walled tubular workpiece.

[0011] Another aspect of the present invention is a device for bulging a special-shaped pipe, comprising a forming die, an upper sealing module, a lower sealing module, a pressure applying module and an internal pressure boosting module, wherein:

[0012] The interior of the molding die is a cavity that matches the shape of the special-shaped pipe;

[0013] The upper sealing module and the lower sealing module respectively seal the top opening and the bottom opening of the tube blank to form a sealed cavity inside thereof;

[0014] The pressure-applying die comprises a pressing block having a diameter greater than the inner diameter of the tube blank and a pressure assembly for applying vertical pressure to the pressing block;

[0015] The internal pressure boosting module comprises a pressure source, a connecting pipe and a sealing channel formed on the lower sealing module or the upper sealing module. The pressure source, the connecting pipe, the sealing channel and the sealing cavity are sealed and connected in sequence.

[0016] In the above technical solution, the pressing block can be inserted into the cavity in a matching manner.

[0017] In the above technical solution, the molding mold includes a lower mold and an upper mold that are detachably connected, and the lower mold cavity inside the lower mold is connected to the upper mold cavity inside the upper mold to form the mold cavity, and the mold cavity corresponding to the wave peak of the circular thin-walled tubular workpiece is half formed at the top of the lower mold cavity and half formed at the bottom of the upper mold cavity.

[0018] In the above technical solution, the upper sealing module includes a detachably connected pressing plate and a top plate and a rubber ring sleeved on the pressing plate, and the rubber ring is squeezed by the top plate to seal the top opening of the circular thin-walled tubular workpiece;

[0019] The lower sealing module comprises a detachably connected top plate with holes and a pressure plate with holes, and a rubber ring sleeved on the pressure plate with holes. The rubber ring is squeezed by the top plate with holes to seal the bottom opening of the circular thin-walled tubular workpiece.

[0020] In the above technical solution, a first stop structure is formed on the perforated top plate, a rubber ring is mounted on the first stop structure, a second stop structure is formed on the pressure plate, a rubber ring is mounted on the second stop structure, the perforated pressure plate is a truncated cone-shaped structure with a "T"-shaped cross-section and a hole, and the pressure plate is a truncated cone-shaped structure with a "T"-shaped cross-section.

[0021] In the above technical solution, a first penetrating channel is formed on the perforated pressure plate, the sealing channel is formed on the perforated top plate, a mounting groove is formed on the lower bottom surface of the perforated top plate, the mounting groove is connected to the sealing channel, a thread is formed on the inner wall of the mounting groove, a sealing gasket is embedded in the mounting groove, and the connecting pipe is locked on the mounting groove by a locking bolt after passing through the first channel, and a sealed connection with the sealing channel is achieved through the sealing gasket.

[0022] In the above technical solution, the pressure source is a gas supply device or a liquid supply device.

[0023] In the above technical solution, the device for expanding special-shaped pipe fittings further comprises a base, and a positioning groove for placing the forming die is formed on the top of the base.

[0024] In the above technical solution, the pressure applying module includes a column fixed on the base, a pressure rod with one end hinged to the top of the column, and a hemispherical block fixed on the bottom surface of the middle part of the pressure rod.

[0025] In the above technical solution, the base is a cylindrical base, the column is fixed to the base by fixing bolts, and the pressure rod is connected to the column by a hinge. A transverse channel for the connecting pipe to pass through is formed on the side wall of the base, and a hollow channel for the connecting pipe to pass through is formed in the center of the base.

[0026] In another aspect of the present invention, the molding method of the molding device comprises the following steps:

[0027] Step 1, placing the tube blank into the forming mold;

[0028] Step 2, using upper and lower sealing modules to seal the upper and lower openings of the tube blank respectively to form a sealed cavity;

[0029] Step 3, placing the pressing block on the top of the tube blank, the pressure component applies vertical pressure to the pressing block, and the pressing block evenly applies pressure F to the top ring wall of the tube blank, driving the tube blank to move downward, while the internal pressure boosting module inflates the sealed cavity with air or liquid to increase the internal pressure of the tube blank, and alternately increases the pressure F and the internal pressure until the tube blank fits the cavity in the forming mold, completing the forming to obtain a round thin-walled tubular workpiece;

[0030] Step 4, when the internal pressure boosting module is pressurized by air pressure, the upper and lower sealing modules are disassembled after the pressure is released, and the circular thin-walled tubular workpiece is removed. When the internal pressure boosting module is pressurized by hydraulic pressure, the liquid is discharged first, and then the upper and lower sealing modules are disassembled.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention provides a forming method and a forming device which utilize an expansion method to extrude a tube blank outward (the expansion method is air pressure expansion or hydraulic expansion), and at the same time drives one end of the tube blank to move axially for compensation, so as to ensure that the air pressure matches the compensation pressure. During the process of increasing the internal pressure of the tubular workpiece, the pressure at the upper end drives one end of the tubular workpiece to move, thereby compensating for the deformation of the tube blank 14. Finally, after the tubular workpiece is fitted with the mold, the forming accuracy is guaranteed, and a circular arc-shaped wave peak without cracking is obtained, thereby reducing the defective rate of special-shaped pipe fittings and improving the processing quality.

[0033] 2. The molding device of the present invention has a simple structure and low processing cost. The sealing structure of the extruded rubber ring is used to seal the openings at both ends of the tube blank 14, which is easy to operate and can effectively ensure the sealing degree. The pressure rod is used to provide axial pressure to the tube blank 14 to ensure the stability of the pressure output. In addition, the mold and the force module are combined together through the base, which improves the convenience of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of a device for expanding and processing special-shaped pipe fittings;

[0035] Figure 2 for Figure 1 A partial enlarged view of

[0036] Figure 3 For the application of the first step of the present invention: schematic diagram of inflation and downward pressure compensation;

[0037] Figure 4 for Figure 3 A partial enlarged view of

[0038] Figure 5 To apply the second step of the present invention: the tube blank 14 (tubular workpiece) is locally deformed;

[0039] Figure 6 In the third step of applying the present invention, the tube blank 14 is fitted with the mold to form a circular thin-walled tubular workpiece.

[0040] In the figure: 1-circular base, 2-lower mold, 3-screw, 4-upper mold, 5-column, 6-pressure rod, 7-bolt, 8-rubber ring, 9-top plate with hole, 10-locking screw, 11-sealing gasket, 12-locking bolt, 13-pressure plate with hole, 14-tube, 15-trachea, 16-constant pressure pump, 17-top plate, 18-pressure plate, 19-pressure block, 20-first channel, 21-sealing channel. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] Example 1

[0043] A method for expanding a special-shaped pipe fitting comprises the following steps:

[0044] Step 1, placing the tube blank 14 into a forming mold;

[0045] Step 2, using upper and lower sealing modules to seal the upper and lower openings of the tube blank 14 to form a sealed cavity;

[0046] Step 3, applying pressure F to the top of the tube blank 14 to drive the tube blank 14 to move downward, and at the same time, filling the sealed cavity with air or liquid, the internal pressure of the tube blank 14 increases, and the pressure F and the internal pressure are alternately increased until the tube blank 14 fits the cavity in the forming mold, and the forming is completed to form a round thin-walled tubular workpiece;

[0047] Step 4: After the pressure is released, disassemble the upper and lower sealing modules and remove the circular thin-walled tubular workpiece.

[0048] Alternatingly increasing the pressure F and the internal pressure of the tube blank 14 can ensure that the internal pressure and the compensation pressure match each other. During the process of increasing the internal pressure of the tube blank 14 (tubular workpiece), the pressure at the upper end drives one end of the tubular workpiece to move, thereby compensating for the deformation of the tube blank 14. Finally, after the tubular workpiece is fitted with the mold, the forming accuracy is guaranteed, and a circular arc-shaped wave peak without cracking is obtained.

[0049] Taking the example of increasing the internal pressure of the tube blank by gas pressure, according to the pressure F=PS, P is the gas pressure, and S is the cross-sectional area. Each time F is increased, the axial compensation is 0.5mm, and the compensation is stopped; according to F=PS, P is increased accordingly.

[0050] Example 2

[0051] A device for expanding a special-shaped pipe fitting comprises a forming die, an upper sealing module, a lower sealing module, a pressure applying module and an internal pressure boosting module, wherein:

[0052] The interior of the molding die is a cavity that matches the shape of the special-shaped pipe fitting;

[0053] The upper sealing module and the lower sealing module respectively seal the top opening and the bottom opening of the tube blank 14 to form a sealed cavity therein;

[0054] The pressure applying die includes a pressing block 19 having a diameter greater than the inner diameter of the tube blank 14 and a pressure component for applying vertical pressure to the pressing block 19;

[0055] The internal pressure boosting module comprises a pressure source, a connecting pipe 15 and a sealing channel formed on the lower sealing module or the upper sealing module. The pressure source, the connecting pipe 15, the sealing channel and the sealing cavity are sealed and connected in sequence.

[0056] The molding method of the molding device comprises the following steps:

[0057] Step 1, placing the tube blank 14 into a forming mold;

[0058] Step 2, using upper and lower sealing modules to seal the upper and lower openings of the tube blank 14 to form a sealed cavity;

[0059] Step 3, placing the pressing block 19 on the top of the tube blank 14, the pressure assembly applies vertical pressure to the pressing block 19, and the pressing block 19 evenly applies pressure F to the top ring wall of the tube blank 14, driving the tube blank 14 to move downward, and at the same time, the internal pressure boosting module inflates the sealed cavity with air or liquid to increase the internal pressure of the tube blank 14, and alternately increases the pressure F and the internal pressure until the tube blank 14 fits the cavity in the forming mold, and the forming is completed to obtain a round thin-walled tubular workpiece;

[0060] Step 4, when the internal pressure boosting module is pressurized by air pressure, the upper and lower sealing modules are disassembled after the pressure is released, and the circular thin-walled tubular workpiece is removed. When the internal pressure boosting module is pressurized by hydraulic pressure, the liquid is discharged first, and then the upper and lower sealing modules are disassembled.

[0061] More preferably, the pressing block 19 can be inserted into the cavity in a matching manner. The pressing block 19 is pressed vertically downward in the cavity, and the cavity can play a guiding role for the pressing block 19 .

[0062] Example 3

[0063] Preferably, the molding die comprises a lower die 2 and an upper die 4, and the lower die 2 and the upper die 4 are fastened by screws 3. When the lower die 2 and the upper die 4 are connected by two screws 3, the lower die cavity inside the lower die 2 is butted with the upper die cavity inside the upper die 4 to form the die cavity, and half of the die cavity corresponding to the wave crest of the circular thin-walled tubular workpiece is formed at the top of the lower die cavity, and the other half is formed at the bottom of the upper die cavity.

[0064] Preferably, the upper sealing module comprises a detachably connected pressing plate 18 and a top plate 17 and a rubber ring 8 mounted on the pressing plate 18, and the rubber ring 8 is squeezed by the top plate 17 to seal the top opening of the circular thin-walled tubular workpiece. The pressing plate 18 and the top plate 17 are connected by a locking screw 10 located in the center. After the locking screw 10 is locked, the pressing plate 18 and the top plate 17 squeeze the rubber ring 8 to achieve a sealing effect.

[0065] The lower sealing module comprises a detachably connected top plate 9 with holes and a pressure plate 13 with holes, and a rubber ring 8 sleeved on the pressure plate 13 with holes. The rubber ring 8 is squeezed by the top plate 9 with holes to seal the bottom opening of the circular thin-walled tubular workpiece. The top plate 9 with holes and the pressure plate 13 with holes are connected by a locking screw 10 located in the center. After the locking screw 10 is locked, the pressure plate 13 with holes and the pressure plate 9 with holes squeeze the rubber ring 8 to play a sealing role.

[0066] Furthermore, a first stop structure is formed on the perforated top plate 9, a rubber ring 8 is mounted on the first stop structure, a second stop structure is formed on the pressure plate 18, a rubber ring 8 is mounted on the second stop structure, the perforated pressure plate 13 is a truncated cone structure with a "T"-shaped cross section and a hole, and the pressure plate 18 is a truncated cone structure with a "T"-shaped cross section.

[0067] More preferably, a first through-channel 20 is formed on the perforated pressure plate 13, a sealing channel 21 is formed on the perforated top plate 9, a mounting groove is formed on the lower bottom surface of the perforated top plate 9, the mounting groove is connected with the sealing channel 21, a thread is formed on the inner wall of the mounting groove, a sealing gasket 11 is embedded in the mounting groove, and the connecting pipe 15 is locked on the mounting groove by a locking bolt 12 after passing through the first channel 20, and is sealed by the sealing gasket 11.

[0068] The locking bolt 12 has a hollow structure inside to fix the end of the connecting pipe 15. When the locking bolt 12 is screwed into the installation groove, it presses the sealing gasket 11, so that the sealing channel and the connecting pipe 15 form a sealed and connected airway. The diameter of the installation groove is larger than the diameter of the sealing channel, and the sealing gasket 11 is embedded in the position between the installation groove and the sealing channel.

[0069] In order to stabilize the pressure increase, the pressure source is a gas supply device or a liquid supply device. More preferably, the pressure source is a constant pressure pump 16.

[0070] In order to facilitate the application of pressure, the device for bulging special-shaped pipe fittings further comprises a base 1, and a positioning groove for placing the forming mold is formed on the top of the base 1. The inner diameter of the positioning groove is equivalent to the outer diameter of the bottom of the forming mold, so as to position the forming mold.

[0071] The pressure applying module comprises a column 5 fixed on the base 1, a pressure rod 6 hinged at one end to the top of the column 5, and a hemispherical block fixed on the bottom surface of the middle part of the pressure rod 6. When the pressure rod 6 is manually pressed down, the hemispherical block applies pressure to the circular thin-walled tubular workpiece through the pressure block 19.

[0072] More preferably, the base 1 is a cylindrical base, the column 5 is fixed to the base 1 by a fixing bolt 7, and the pressure rod 6 is connected to the column 5 by a hinge. A transverse channel for the connecting pipe 15 to pass through is formed on the side wall of the base 1, and a hollow channel for the connecting pipe 15 to pass through is formed in the center of the base 1. One end of the connecting pipe 15 is connected to the constant pressure pump 16, and the other end is connected to the lower sealing module after passing through the transverse channel and the hollow channel.

[0073] The workflow of this embodiment is as follows:

[0074] Step 1, use screws 3 to connect the upper mold 4 and the lower mold 2;

[0075] Step 2, placing the tube blank 14 into the cavity between the upper mold 4 and the lower mold 2;

[0076] Step 3, placing the perforated pressing plate 13 and the perforated top plate 9 into the bottom of the tube blank 14, connecting the perforated pressing plate 13 and the perforated top plate 9 with the locking screws 10, squeezing the rubber ring 8, and fitting the rubber ring 8 with the inner wall of the tube blank 14 to achieve sealing of the lower end of the tube blank 14;

[0077] The top plate 17 is placed in the tube blank 14 so that it is located on the perforated top plate 9, and then the pressing plate 18 is locked on the top plate 17 by the locking screw 10. During the locking process, the rubber ring 8 sleeved on the pressing plate 18 is squeezed, and the rubber ring 8 fits with the inner wall of the tube blank 14 to achieve sealing of the upper end of the tube blank 14;

[0078] Step 4, placing the assembled upper mold 4, lower mold 2 and tube blank 14 together on the circular base 1;

[0079] Step 5, placing the pressing block 19 on the upper end of the tube blank 14, such as Figure 1 As shown;

[0080] Step 6: Apply pressure F to one end of the pressure rod 6, such as Figure 3 As shown, the constant pressure pump 16 is operated to increase the pressure in the connecting pipe 15. The pressure F and the pressure in the air pipe are increased alternately until the pressure in the air pipe reaches the set value (the set value is about 20Mp, which fluctuates slightly according to the actual working conditions). The local changes of the tube blank 14 are shown in FIG. Figure 4 , Figure 5 and Figure 6 As shown, the tube blank 14 is partially convex and fills the cavity formed by the upper mold 4 and the lower mold 2, and fits with the mold to form a round thin-walled tubular workpiece; in order to visually observe the pressure in the connecting pipe 15, a pressure gauge is installed on the connecting pipe 15;

[0081] Step 7, disassemble all parts after pressure relief and remove the circular thin-walled tubular workpiece.

[0082] For ease of explanation, spatial relative terms such as "upper", "lower", "left", "right" and the like are used in the embodiments to illustrate the relationship of one element or feature shown in the figure relative to another element or feature. It should be understood that, in addition to the orientation shown in the figure, the spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is inverted, the element described as being "under" other elements or features will be positioned "on" other elements or features. Therefore, the exemplary term "under" can include both upper and lower orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here can be interpreted accordingly.

[0083] Furthermore, relational terms such as “first” and “second” and the like are merely used to distinguish one component from another having the same name, but do not necessarily require or imply any such actual relationship or order between these components.

[0084] The above is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for bulging a special-shaped pipe fitting, characterized in that: The following steps are involved: Step 1, placing the tube blank into the forming mold; Step 2, using upper and lower sealing modules to seal the upper and lower openings of the tube blank to form a sealed cavity; Step 3, placing the pressing block on the top of the tube blank, the pressure assembly applies vertical pressure to the pressing block, and the pressing block evenly applies pressure F to the top ring wall of the tube blank, driving the tube blank to move downward, while the internal pressure boosting module inflates the sealed cavity with air or liquid to increase the internal pressure of the tube blank, and alternately increases the pressure F and the internal pressure until the tube blank fits the cavity in the forming mold, and the forming is completed to obtain a round thin-walled tube-shaped special-shaped pipe fitting; Step 4, after the pressure is released, the upper and lower sealing modules are disassembled, and the round thin-walled tubular special-shaped pipe fittings are removed; The method uses a device for expanding special-shaped pipe fittings, which includes a forming die, an upper sealing module, a lower sealing module, a pressure applying module and an internal pressure boosting module, wherein: The interior of the molding die is a cavity that matches the shape of the round thin-walled tube-shaped special-shaped pipe; The upper sealing module and the lower sealing module respectively seal the top opening and the bottom opening of the tube blank to form a sealed cavity inside thereof; The pressure applying module comprises a pressing block having a diameter greater than the inner diameter of the tube blank and a pressure component for applying vertical pressure to the pressing block; The internal pressure boosting module comprises a pressure source, a connecting pipe and a sealing channel formed on the lower sealing module or the upper sealing module, and the pressure source, the connecting pipe, the sealing channel and the sealing cavity are sealed and connected in sequence; The pressing block is matched and inserted into the cavity; The molding mold includes a lower mold and an upper mold that are detachably connected. The lower mold cavity inside the lower mold is connected to the upper mold cavity inside the upper mold to form the molding cavity. The mold cavity corresponding to the wave crest of the circular thin-walled tubular special-shaped pipe fitting is half formed at the top of the lower mold cavity and half formed at the bottom of the upper mold cavity.

2. The method according to claim 1, characterized in that The upper sealing module comprises a detachably connected pressing plate and a top plate and a rubber ring sleeved on the pressing plate, wherein the rubber ring is squeezed by the top plate to seal the top opening of the circular thin-walled tubular special-shaped pipe fitting; The lower sealing module comprises a detachably connected perforated top plate and a perforated pressure plate and a rubber ring sleeved on the perforated pressure plate. The rubber ring is squeezed by the perforated top plate to seal the bottom opening of the circular thin-walled tubular special-shaped pipe fitting.

3. The method according to claim 2, characterized in that A first stop structure is formed on the perforated top plate, a rubber ring is mounted on the first stop structure, a second stop structure is formed on the pressure plate, a rubber ring is mounted on the second stop structure, the perforated pressure plate is a truncated cone structure with a "T"-shaped cross section and a hole, and the pressure plate is a truncated cone structure with a "T"-shaped cross section.

4. The method according to claim 2, characterized in that A first penetrating channel is formed on the perforated pressure plate, the sealing channel is formed on the perforated top plate, a mounting groove is formed on the lower bottom surface of the perforated top plate, the mounting groove is connected with the sealing channel, a thread is formed on the inner wall of the mounting groove, a sealing gasket is embedded in the mounting groove, the connecting pipe is locked on the mounting groove by a locking bolt after passing through the first channel, and a sealed connection with the sealing channel is achieved through the sealing gasket.

5. The method according to claim 1, characterized in that The pressure source is a gas supply device or a liquid supply device.

6. The method according to claim 1, characterized in that The device for expanding special-shaped pipe fittings also includes a base, and a positioning groove for placing the forming mold is formed on the top of the base.

7. The method according to claim 6, characterized in that The pressure assembly comprises a column fixed on the base, a pressure rod with one end hinged to the top of the column, and a hemispherical block fixed on the bottom surface of the middle part of the pressure rod.

8. The method according to claim 7, characterized in that The base is a cylindrical base, the column is fixed to the base by fixing bolts, and the pressure rod is connected to the column by a hinge; a transverse channel for the connecting pipe to pass through is formed on the side wall of the base, and a hollow channel for the connecting pipe to pass through is formed in the center of the base.

9. The method according to claim 1, characterized in that Specifically, step 4 is as follows: when the internal pressure boosting module is pressurized by air pressure, the upper and lower sealing modules are disassembled after the pressure is released, and the circular thin-walled tubular special-shaped pipe fittings are removed; when the internal pressure boosting module is pressurized by hydraulic pressure, the liquid is discharged first, and then the upper and lower sealing modules are disassembled.

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