CN113441599B - Hydraulic forming and flaring combined process and device for tubular part - Google Patents
Hydraulic forming and flaring combined process and device for tubular part Download PDFInfo
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- CN113441599B CN113441599B CN202010219042.XA CN202010219042A CN113441599B CN 113441599 B CN113441599 B CN 113441599B CN 202010219042 A CN202010219042 A CN 202010219042A CN 113441599 B CN113441599 B CN 113441599B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
- B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
- B21D26/033—Deforming tubular bodies
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D41/00—Application of procedures in order to alter the diameter of tube ends
- B21D41/02—Enlarging
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- Shaping Metal By Deep-Drawing, Or The Like (AREA)
Abstract
A hydraulic forming and flaring combined process and a device for tubular parts belong to the field of machining. The contour line of the end part of the pipe fitting is divided into a plurality of segment areas; pressing partial areas of the end part of the pipe fitting at intervals to ensure that the pressed areas are not deformed, and performing primary flaring on the areas which are not pressed; and pressing the formed part of the end part of the pipe fitting at intervals during the first flaring, and performing the second flaring on the unformed area to obtain the tubular part with the shape of the final required bell mouth. The pipe fitting end part flaring device has the advantages that through the mode of twice combined flaring, the free deformation of the whole flaring of the pipe fitting end part is dispersed into the free deformation of a plurality of small sections, and the precision of the size of the 'bell mouth' contour line of the pipe fitting end part is guaranteed. The welding line of the horn mouth at the end part of the pipe fitting is longer, and meanwhile, the port is turned outwards, so that the pipe fitting can be welded in the thickness direction of the material in the subsequent two-stage welding process, the pipe fitting is well attached to the profile of the outer contour of the cross beam, and the stability of a welding part is enhanced. Can be widely applied to the field of processing and manufacturing of tubular parts.
Description
Technical Field
The invention belongs to the field of machining, and particularly relates to a hydraulic forming and flaring combined process and device for a tubular part.
Background
The tubular part has a closed section, and can provide better rigidity and strength, so that the tubular part is widely applied to the fields of aerospace, automobiles, building industries and the like.
However, compared with the connection between pipes, the difficulty of punching parts by plates is high, and the common spot welding method for connection cannot be generally applied because a welding gun is difficult to extend into the pipe.
At present, two-protection welding is generally adopted for connecting a pipe and a pipe, the pipe end of one tubular part is welded on the other tubular part in a whole circle, in order to ensure the welding strength and the welding stability, the pipe end needs to be welded in the thickness direction of the pipe end, meanwhile, the length of the welding line is increased, so the pipe end is generally in a 'bell mouth' shape, the extension of the bell mouth 'compared with the circumferential material of the original straight pipe can reach more than 50% on average, meanwhile, the bell mouth' is generally asymmetric, the extension of the local material even exceeds 100%, and the extension limit of the material is exceeded. In addition, because of "horn mouth" outer profile whole circle and overlap joint tubular part outline two protect and weld, have higher requirement to "horn mouth" outer profile line dimensional accuracy.
In order to enlarge the pipe diameter of the pipe, a hydroforming process is generally adopted, which includes the steps of bending and preforming the part as required, and then injecting high-pressure liquid into two ends of the pipe, so that the pipe diameter is enlarged in the circumferential direction. However, for the pipe fitting with the bell mouth, one-time hydraulic forming exceeds the elongation limit of the material, the process generally adopted by the prior art is to carry out multiple times of hydraulic forming on the pipe fitting and carry out annealing treatment between working procedures, so that the plasticity of the material is improved, and the process is complex, the production efficiency is low and the cost is high.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a tubular part hydraulic forming and flaring combined process and a device. The pipe end contour line is segmented, then a secondary flaring process is adopted, the free deformation of the whole flaring of the pipe end is dispersed into small segments, and the size precision of the pipe end contour line can be guaranteed. The method comprises the steps of carrying out hydraulic bulging on the tubular part, then carrying out trimming treatment on the tube end, and then carrying out flaring, so that the local plastic deformation capacity of the tubular part material is fully utilized, the plasticity of the tubular part material is exerted, and the final part with the required part outer contour line bell-mouth structure can be obtained without an intermediate annealing process.
The technical scheme of the invention is as follows: providing (a tubular part hydraulic forming and flaring combined process, which comprises flaring of the end part of a tubular part to be developed, and is characterized in that:
1) Splicing a left part and a right part of a tubular part to be developed for designing a middle process part, and supplementing a design process of a horn mouth at the end part;
2) Carrying out computer forming simulation and judging formability;
3) Carrying out numerical control pipe bending on the tubular part to be developed;
4) Carrying out hydraulic bulging forming on the tubular part;
5) Trimming the end part of the pipe fitting after the hydraulic forming, and separating a left part from a right part;
6) Dividing the contour line of the end part of the pipe fitting into a plurality of segment areas;
7) Pressing partial areas of the end part of the pipe fitting at intervals to enable the pressed areas not to deform, and performing first flaring on the areas not pressed to enable the areas not pressed to reach the final part contour line position of the bell mouth at the end part of the pipe fitting;
8) And pressing the formed part of the pipe fitting end part 'bell mouth' at intervals during the first flaring, and performing second flaring on the unformed area of the pipe fitting end part 'bell mouth' to obtain the tubular part with the final required 'bell mouth' shape.
According to the hydraulic forming and flaring combined process for the tubular part, disclosed by the technical scheme of the invention, the free deformation of the integral flaring of the end part of the pipe fitting is dispersed into the free deformation of a plurality of small sections in a secondary combined flaring manner, so that the accuracy of the contour line size of the bell mouth of the end part of the pipe fitting is ensured.
The segment area comprises a plurality of pressing areas arranged at intervals and a plurality of forming areas arranged at intervals; wherein each hold down region is located adjacent to a forming region.
Specifically, when first flaring is performed, all pressing areas are pressed, so that the pressing areas are not deformed, and all forming areas are subjected to first flaring;
before the second flaring is carried out, the pressing area and the forming area during the first flaring are exchanged, all the forming areas during the first flaring are regarded as pressing areas, and all the pressing areas during the first flaring are regarded as forming areas;
and during secondary flaring, pressing all pressing areas ' so that the pressing areas ' are not deformed, and performing secondary flaring on all forming areas ' to finally obtain the final part with the required part outer contour line ' bell mouth ' structure.
According to the hydraulic forming and flaring combined process for the tubular part, the final part with the required part outer contour line bell mouth structure is obtained by adopting a secondary hydraulic forming and flaring combined process for the end part of the tubular part, the precision of the size of the pipe fitting end bell mouth contour line can be guaranteed, the pipe fitting end bell mouth welding line is longer, meanwhile, the end port is turned outwards, so that the welding can be carried out in the material thickness direction in the subsequent secondary welding process, the better fit with the cross beam outer contour profile is guaranteed, and the stability of the welding part is enhanced.
The technical scheme of the invention also provides a flaring device adopting the hydraulic forming and flaring combined process of the tubular part, which is characterized in that:
the flaring device comprises an upper die, a lower die, a flaring punch, a material pressing punch, a rear seat plate, a material pressing punch connecting sleeve, a resetting connecting sleeve and a resetting stop block;
the material pressing punch is sleeved on the periphery of the flaring punch;
the longitudinal axis of the material pressing punch and the longitudinal axis of the flaring punch are overlapped;
the rear end of the rear seat plate is connected with the hydraulic cylinder to provide flaring thrust;
the upper die and the lower die are respectively connected with the upper bottom plate and the lower bottom plate of the press to provide die closing force;
a nitrogen cylinder is arranged at the rear part of the connecting sleeve of the material pressing punch to provide material pressing force;
when the first flaring is carried out, the trimmed tubular part is placed on a lower die, the upper die and the lower die cooperate to clamp the tubular part, a rear seat plate is pushed forward under the action of a hydraulic cylinder, a nitrogen cylinder is pressed to enable the end part of a material pressing punch to be firstly contacted and pressed with a pressing area of the end part of the tubular part to be flared, partial area of the end part of a pipe fitting is pressed at intervals, and the pressing area is not deformed;
the rear seat plate continues to push the end part of the flaring punch head to be in contact with an unpressed area at the end part of the tubular part to be flared, and primary flaring is carried out on the unpressed area to enable the unpressed area to reach the final part contour line position of a bell mouth at the end part of the pipe fitting;
then, exchanging the pressing area and the forming area during the first flaring, and regarding all the forming areas during the first flaring as pressing areas 'and regarding all the pressing areas during the first flaring as forming areas';
and during secondary flaring, the end part of the material pressing punch presses all the pressing areas ' so that the pressing areas ' are not deformed, and the end part of the flaring punch performs secondary flaring on all the forming areas ' so as to finally obtain the final part with the ' bell mouth ' structure of the outer contour line of the part.
Furthermore, in the process of retracting the rear seat plate under the action of the hydraulic cylinder, the flaring punch head retracts firstly; after the reset stop block is connected with the material pressing punch head in a sleeved mode, the material pressing punch head returns to reset under the action of the reset stop block; the method realizes the process of pressing partial areas of the end part of the pipe fitting at intervals, so that the pressed areas are not deformed, and flaring is performed on the non-pressed areas in a fractional manner.
Specifically, the pressing punch connecting sleeve and the resetting connecting sleeve are guided by a copper guide plate; a copper guide plate is adopted for guiding between the material pressing punch and the flaring punch; the material pressing punch is connected on the material pressing punch connecting sleeve through a bolt, the reaming punch is connected on the rear seat plate through a bolt, the resetting connecting sleeve is connected on the rear seat plate through a bolt, and the resetting stop block is connected on the resetting connecting sleeve through a bolt; the pressing punch and the flaring punch can slide relatively; the material pressing punch connecting sleeve and the resetting connecting sleeve can slide relatively.
The flaring device adopts a 'secondary flaring' process, firstly performs primary flaring on the connecting end part of the tubular part, then performs secondary flaring on the connecting end part of the tubular part, and disperses the free deformation of the integral flaring of the end part of the pipe fitting into the free deformation of a plurality of small sections in a secondary combined flaring manner to ensure the precision of the 'bell mouth' contour line size of the end part of the pipe fitting.
The flaring device can better exert the local plastic deformation capacity of the material during flaring, can better exert the plasticity of the material, and can obtain the final part with the structure of the required part outer contour line 'bell mouth' without an intermediate annealing process.
Compared with the prior art, the invention has the advantages that:
1. the tubular part is adopted to design the structure, has a closed section structure and has better rigidity and strength, so that compared with the conventional two-plate stamping part, the box-shaped part is formed by spot welding, and the performance is better.
2. The tubular parts are connected through the horn mouth, the end part of one pipe fitting is connected to the other tubular part in a whole circle, so that the welding line of the horn mouth is longer, meanwhile, the port is turned outwards, welding is carried out in the material thickness direction in the subsequent two-stage welding process, the better fit with the profile of the outer contour of the cross beam is guaranteed, and the welding stability is good.
3. The method adopts a hydraulic forming and flaring combined process, firstly carries out hydraulic bulging on the tubular part, then carries out trimming treatment on the tube end, and then carries out flaring, wherein the trimming treatment and the trimming treatment on the tube end are the process supplement part of the part, so that the constraint of the material of the process supplement part is lost during flaring, the local plastic deformation capability of the material can be better exerted, the plasticity of the material can be better exerted, and an intermediate annealing process is not needed; the whole manufacturing process is simple, the production efficiency is high, the cost is low, and the product size precision is high.
4. Adopting a twice flaring combined process to divide the contour line of the end part (pipe end for short) of the pipe fitting into a plurality of segmentation areas, pressing partial areas of the pipe end at intervals during the first flaring so that the pressed areas are not deformed, and flaring the areas which are not pressed so as to achieve the final part contour line position; when flaring is carried out for the second time, the formed part is pressed at intervals, and flaring is carried out on the unformed area; by the twice combined flaring method, the free deformation of the whole flaring of the pipe end can be dispersed into the free deformation of a plurality of small sections, so that the size precision of the contour line of the pipe end can be guaranteed.
Drawings
FIG. 1a is a schematic view of a connection structure of a tubular member and a tubular member;
FIG. 1b is an enlarged view of a portion A of FIG. 1 a;
FIG. 2a is a schematic view of the "bell mouth" shaped configuration of the end of the tubular element;
FIG. 2B is an enlarged view of a portion B of FIG. 2 a;
FIG. 3a is a schematic view of the shape and structure of a tubular part after hydroforming;
FIG. 3b is an enlarged view of a portion C of FIG. 3 a;
FIG. 4 is a schematic view of a trimmed tubular part;
FIG. 5 is a schematic view of the outline of the trimmed tubular part compared to the outline of the final part;
FIG. 6 is a schematic view of the outline of the trimmed tubular part compared to the outline of the first flare;
FIG. 7 is a schematic structural view of parts after first flaring;
FIG. 8 is a schematic view of the outer contour of the final part after first flaring as compared to the outer contour of the final part;
FIG. 9 is a schematic isometric side view of a flaring device of the present invention;
FIG. 10 is a front view of the flaring device;
FIG. 11 isbase:Sub>A schematic view of the section A-A in FIG. 10;
FIG. 12 is an enlarged partial view of portion D of FIG. 11;
FIG. 13 is a schematic top view of the flaring device;
FIG. 14 is a schematic structural view of section B-B in FIG. 13;
FIG. 15 is a flow block diagram of the combined hydroforming and flaring process of the present invention.
In the figure, 101 is a crossbeam, 102 is a left trailing arm, 103 is a right trailing arm,
ZLKX is the final part outer contour line, XLKX is the trimmed outer contour line,
901 is an upper die, 902 is a lower die, 903 is a pipe fitting to be flared, 904 is a flaring punch, 905 is a pressing punch, 906 is a reset block, 907 is a reset connecting sleeve, 908 is a rear seat plate, 910 is a pressing punch connecting sleeve, 911 is a flaring punch, 912 is a pressing punch, 913 is a pressing punch connecting sleeve, 914 is a nitrogen cylinder, and 915 is a pipe fitting pipe end forming area to be flared.
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
In the mechanical engineering manufacturing, tubular parts (called pipes, pipe fittings or parts for short) have closed sections and can provide better rigidity and strength, so that the tubular parts are widely applied to the fields of aerospace, automobiles, building industries and the like.
But the connection between the pipes is difficult to be compared with the connection of plate stamping parts; the method is suitable for a spot welding method commonly used for connecting plate pieces, and the welding gun cannot be applied to connection between two pipes generally because the welding gun cannot extend into the pipe easily.
At present, for the connection between pipes, two kinds of welding (called carbon dioxide gas shielded welding entirely) are generally adopted to weld the pipe end (for short, pipe end) of one tubular part on the other tubular part in a whole circle.
In order to ensure the welding strength and stability, it is necessary to perform welding operation in the thickness direction of the pipe end, and in order to increase the length of the welding line, a "bell mouth" shape is generally pre-machined at the pipe end of the tubular part, as shown in fig. 2a and 2 b.
Compared with the original straight pipe, the material elongation in the circumferential direction of the flare opening can reach more than 50 percent on average; meanwhile, in order to better fit the outer contour of the overlapped tubular part, the bell mouth is generally asymmetric, and the elongation of local materials even exceeds 100 percent and exceeds the limit of the elongation of the materials.
In addition, because the whole circle of the outer contour line of the bell mouth is welded with the outer contour of the lap joint tubular part for two times, the requirement on the dimensional accuracy of the outer contour line of the bell mouth is high.
In order to enlarge the pipe diameter of the pipe, a hydroforming process is generally adopted at present, which comprises the steps of bending and preforming the parts as required, and then injecting high-pressure liquid into two ends of the pipe, so that the pipe diameter of the pipe is enlarged in the circumferential direction.
However, the single-pass hydroforming of a pipe with a "bell mouth" structure exceeds the elongation limit of the material, so the prior art generally adopts a manufacturing process of hydroforming the pipe for multiple times and annealing treatment between the processes to improve the plasticity of the material. The manufacturing process can lead to complex whole processing technology, low production efficiency and high cost.
Specifically, as shown in fig. 1a and 1b, a schematic diagram of a connection structure between a tubular part and a tubular part of a rear suspension of an automobile is provided.
The tubular part of the rear suspension of the automobile comprises a cross beam 101 and two trailing arms (shown as a left trailing arm 102 and a right trailing arm 103).
Wherein, the tip of two trailing arms and crossbeam joint portion is "horn mouth" shape, and the port turns up for follow-up two protect the welding in-process, can weld in the material thickness direction, guarantee simultaneously with the better laminating of crossbeam outline profile. FIG. 1b is an enlarged view of a portion A (i.e., the "flare" shape of the trailing arm end) of FIG. 1 a.
In fig. 2a and 2B, a schematic view of the end "bell mouth" shape structure (indicated by part B in the figure) of two trailing arm tubular components is separately shown to assist the reader in understanding the end "bell mouth" shape structure of the tubular components.
In actual manufacturing, for two longitudinal arm parts, after the left longitudinal arm part and the right longitudinal arm part are spliced, the spliced parts are bent firstly, and then hydraulic forming is carried out.
The above-mentioned process of hydroforming "flare" is shown in fig. 3a, and fig. 3b is a partial structure enlarged view of the portion C in fig. 3 a. In the specific process of machining and forming, simulation is used as a guide, field actual debugging is combined, and the hydroformed pipe fitting is obtained through end sealing propulsion in the hydroforming process.
The final structure of the hydroformed tube is shown in fig. 4.
Next, the hydroformed part is laser cut and trimmed, with the trimmed outer contour line XLKX aligned with the final part outer contour line ZLKX as shown in FIG. 5.
As described above, if the end of the tubular part is directly flared according to the prior art, the deformation of the end material of the entire turn of the tubular part is in a freely deformed state, and the dimensional accuracy of the outer contour line of the "flare" is poor.
In the technical scheme of the invention, flaring is divided into two times, and the trimmed outer contour line XLKX of the tubular part is aligned with the outer contour line of the first flaring, as shown in figure 6.
Specifically, as shown in fig. 6, when performing first flaring, the flaring device in the technical solution of the present invention keeps pressing the pressing region 1, the pressing region 2, the pressing region 3, the pressing region 4, and the pressing region 5 (i.e. the aforementioned pressing regions arranged at intervals), and flares and forms the spaced forming regions a, B, C, D, and E (i.e. the aforementioned forming regions arranged at intervals). The tubular part after the first flaring is shown in figure 7.
A schematic diagram comparing the outer contour line after the first flaring with the outer contour line ZLKX of the final part is shown in fig. 8.
Then, when the tubular part is flared for the second time, the pressing area and the forming area during the first flaring are exchanged, all the forming areas during the first flaring are regarded as pressing areas, and all the pressing areas during the first flaring are regarded as forming areas; when in secondary flaring, all the pressing areas ' are pressed, so that the pressing areas ' are not deformed, and all the forming areas ' are flared for the second time
Specifically, as shown in fig. 8, the pressing areas 11, 12, 13, 14, 15 are held pressed by the flaring device of the present invention, and the spaced forming areas H, I, J, K, L are flared.
After twice flaring, the final part with the required part outer contour line 'bell mouth' structure can be finally obtained.
The first flaring is similar to the second flaring by the same apparatus, and the first flaring is described as an example.
As shown in fig. 9 to 14, the flaring device includes an upper die 901, a lower die 902, a flaring punch 904, a swaging punch 905, a back seat plate 908, a swaging punch connecting sleeve 910, a reset connecting sleeve 907, and a reset stopper 906.
As can be seen from fig. 9-14, in the technical solution of the present invention, the relationship between the pipe and the mold is as follows: a reset connecting sleeve is arranged in front of the rear seat plate, and a reset stop block is arranged in front of the reset connecting sleeve; inside, the flaring punch is connected with the back seat plate; the nitrogen cylinder is arranged behind the connecting sleeve of the material pressing punch, the material pressing punch and the flaring punch can slide relatively, and the connecting sleeve of the material pressing punch and the reset connecting sleeve can slide relatively. The pipe fitting is positioned between the upper die and the lower die, and the flaring punch and the material pressing punch are positioned outside the end of the pipe to be flared.
Wherein, the rear end of the rear seat plate is connected with the hydraulic cylinder to provide flaring thrust; the upper die and the lower die are respectively connected with an upper bottom plate and a lower bottom plate of the press to provide a die closing force, and a nitrogen cylinder 914 is arranged at the rear part of the material pressing punch connecting sleeve 910 to provide a material pressing force. The connecting sleeve of the material pressing punch head and the reset connecting sleeve 907 are guided by a copper guide plate, and the material pressing punch head 905 and the flaring punch head 911 are guided by a copper guide plate. Press the material drift to pass through bolted connection on pressing material drift adapter sleeve 913, the reaming drift is through being connected on the bedplate of back, and the adapter sleeve that resets passes through bolted connection on the bedplate of back, and dog 906 that resets passes through bolted connection and sheathes in the reset connection.
The trimmed tubular part (shown as a pipe fitting 903 to be flared in the figure) is placed on a lower die, the upper die and the lower die cooperate to clamp the tubular part, a rear seat plate is pushed forward under the action of a hydraulic cylinder, a nitrogen cylinder is pressed to enable a material pressing punch to be pressed tightly, the rear seat plate continues to push a flaring punch to be in contact with a pipe fitting port, and a region 915 to be formed is formed. In the process that the rear seat plate retreats under the action of the hydraulic cylinder, the flaring punch retreats firstly due to the bolt connection with the rear seat plate. After the reset stop block is connected with the material pressing punch head in a sleeved mode, the material pressing punch head returns and resets under the action of the reset stop block.
From the above description, it can be appreciated that the tubular part hydroforming and flaring combined process of the present invention can be summarized as the flow steps shown in fig. 15.
In fig. 15, for the pipe fitting to be developed, the invention firstly designs the middle process part, splices the left and right parts, and supplements the end part 'bell mouth' design process; carrying out forming simulation, and judging formability; the purpose of this step is through simulation, obtain reasonable intermediate process part design.
Secondly, carrying out numerical control pipe bending; for tubular parts with large-radius bends, a numerical control bend pipe is required to be firstly moved (the numerical control bend pipe is a common previous process for hydroforming).
Then, carrying out hydroforming; and the hydraulic forming comprises the steps of carrying out hydraulic forming debugging and optimizing the process by combining simulation and debugging conditions.
Trimming the hydroformed tubular part; also comprises separating the left and right pieces.
The second flaring process is adopted, and the first flaring is firstly carried out on the connecting end part of the tubular part.
And then carrying out secondary flaring on the connecting end part of the tubular part.
Finally, the final part is obtained with the desired "bell mouth" configuration of the part outer contour.
Obviously, the technical scheme of the invention has the following advantages:
(1) Advantages of the tubular part design: because the tubular part has a closed cross-sectional structure and has better rigidity and strength, the performance is better than that of a conventional two-sheet stamped part formed into a box by spot welding.
(2) Tubular parts are connected through a 'bell mouth': because the connection mode of the tubular parts is that the end part of one pipe fitting is connected to the other tubular part in a whole circle mode, the welding line of the bell mouth is longer, and meanwhile, the port is turned outwards, so that in the subsequent two welding processes, the welding is carried out in the material thickness direction, the better fit with the profile of the outer contour of the cross beam is ensured, and the welding stability is good.
(3) The hydraulic forming and flaring combined process has the technical advantages that: the forming mode of the bell mouth of the tubular part commonly used in the industry is two-time or multi-time hydraulic forming, and intermediate annealing is carried out in the process to improve the plasticity of the material, so the process is complex and the cost is high. The hydraulic forming and flaring combined process provided by the invention has the advantages of simple process and low cost. Meanwhile, the tubular part is subjected to hydraulic bulging firstly, then the pipe end is subjected to trimming treatment and then flaring is carried out, and the process supplement part of the part is trimmed by the trimming treatment of the pipe end, so that the constraint of the material of the process supplement part is lost during flaring, the local plastic deformation capability of the material can be better exerted, the plasticity of the material can be better exerted, and an intermediate annealing process is not needed.
(4) The double flaring combined process has the advantages that: the contour line of the pipe end is segmented, the sub-areas of the pipe end are pressed at intervals by the flaring for the first time, so that the sub-areas are not deformed, the flaring is not pressed, the final part contour line position is reached, the formed part is pressed at intervals by the flaring for the second time, and the unformed area of the flaring is formed.
In conclusion, the technical scheme of the invention fully utilizes the characteristic that the plastic deformation of the flaring process material is more uniform, and the phenomenon of necking of concentrated instability is not easy to occur; meanwhile, the free deformation of the integral flaring of the end part of the pipe fitting is dispersed into the free deformation of a plurality of small sections by adopting a twice combined flaring mode, so that the accuracy of the contour line size of the bell mouth of the end part of the pipe fitting is ensured; the local plastic deformation capacity of the material can be better exerted, the plasticity of the material can be better exerted, and the final part with the required part outer contour line bell mouth structure can be obtained without an intermediate annealing process.
The implementation of the technical scheme of the invention can solve the practical problems of multiple times of hydraulic forming and intermediate annealing, complex process, low production efficiency, high cost and the like in the prior art.
The invention can be widely applied to the field of processing and manufacturing of tubular parts.
Claims (8)
1. A tubular part hydroforming and flaring combined process comprises flaring of the end part of a tubular part to be developed, and is characterized in that:
1) The middle process part is designed for the tubular part to be developed, the left and right parts are spliced, and the design process of a horn mouth at the end part is supplemented;
2) Carrying out computer forming simulation and judging formability;
3) Carrying out numerical control pipe bending on the tubular part to be developed;
4) Carrying out hydraulic bulging forming on the tubular part;
5) Trimming the end part of the pipe fitting after the hydroforming, and separating a left part from a right part;
6) Dividing the contour line of the end part of the pipe fitting into a plurality of segment areas;
7) Pressing partial areas of the end part of the pipe fitting at intervals to enable the pressed areas not to deform, and performing first flaring on the areas not pressed to enable the areas not pressed to reach the final part contour line position of the bell mouth at the end part of the pipe fitting;
8) Pressing the formed part of the pipe fitting end part bell mouth at intervals when the pipe fitting end part bell mouth is flared for the first time, and flaring for the second time on the unformed area of the pipe fitting end part bell mouth to obtain the tubular part in the shape of the final required bell mouth;
the segmentation areas comprise a plurality of pressing areas arranged at intervals and a plurality of forming areas arranged at intervals; wherein each hold down region is disposed adjacent to one of the forming regions;
the hydraulic forming and flaring combined process for the tubular part ensures the accuracy of the contour line size of the bell mouth of the end part of the pipe fitting by freely deforming the whole flaring of the end part of the pipe fitting into a plurality of small sections in a secondary combined flaring mode.
2. The combined hydroforming and flaring process of a tubular part according to claim 1, wherein during the first flaring, all the hold down areas are held down so that the hold down areas are not deformed and all the forming areas are flared for the first time;
before the second flaring is carried out, the pressing area and the forming area during the first flaring are exchanged, all the forming areas during the first flaring are regarded as pressing areas, and all the pressing areas during the first flaring are regarded as forming areas;
and during secondary flaring, pressing all pressing areas ' so that the pressing areas ' are not deformed, and performing secondary flaring on all forming areas ' to finally obtain the final part with the required part outer contour line ' bell mouth ' structure.
3. The tubular part hydroforming and flaring combined process according to claim 1, wherein the tubular part hydroforming and flaring combined process is characterized in that a secondary hydroforming and flaring combined process is adopted for the end part of the tubular part to obtain a final part with a required part outer contour line bell-mouth structure, the precision of the pipe part end bell-mouth contour line size can be guaranteed, the pipe part end bell-mouth welding line length is longer, meanwhile, the port is turned outwards, so that the welding can be carried out in the material thickness direction in the subsequent two-time welding process, the better fit with the outer contour profile of the cross beam is guaranteed, and the stability of the welding part is enhanced.
4. A flaring device using the combined hydroforming and flaring process of the tubular part of claim 1, characterized in that:
the flaring device comprises an upper die, a lower die, a flaring punch, a material pressing punch, a rear seat plate, a material pressing punch connecting sleeve, a resetting connecting sleeve and a resetting stop block;
the material pressing punch is sleeved on the periphery of the flaring punch;
the longitudinal axis of the material pressing punch and the longitudinal axis of the flaring punch are overlapped;
the rear end of the rear seat plate is connected with the hydraulic cylinder to provide flaring thrust;
the upper die and the lower die are respectively connected with the upper bottom plate and the lower bottom plate of the press to provide die closing force;
a nitrogen cylinder is arranged at the rear part of the connecting sleeve of the material pressing punch to provide material pressing force;
when the first flaring is carried out, the trimmed tubular part is placed on the lower die, the upper die and the lower die cooperate to clamp the tubular part, the rear seat plate is pushed forward under the action of the hydraulic cylinder, the nitrogen cylinder is pressed to enable the end part of the material pressing punch to be firstly contacted and pressed with a pressing area of the end part of the tubular part to be flared, and partial area of the end part of the pipe fitting is pressed at intervals, so that the pressing area is not deformed;
the rear seat plate continues to push the end part of the flaring punch head to contact with an unpressed region of the end part of the tubular part to be flared, and flaring is carried out on the unpressed region for the first time, so that the final part contour line position of the 'bell mouth' at the end part of the pipe fitting is achieved;
then, the pressing area and the forming area during first flaring are exchanged, all the forming areas during first flaring are regarded as pressing areas, and all the pressing areas during first flaring are regarded as forming areas;
and during secondary flaring, the end part of the pressing punch presses all pressing areas ' so that the pressing areas ' are not deformed, and the end part of the flaring punch performs secondary flaring on all forming areas ' so as to finally obtain the final part with the required part outer contour line ' bell mouth ' structure.
5. The flaring device of claim 4, wherein during retraction of the rear seat plate under the action of the hydraulic cylinder, the flaring punch is retracted first; after the reset stop block is connected with the material pressing punch head in a sleeved mode, the material pressing punch head returns to reset under the action of the reset stop block; and realizing the process of pressing partial areas of the end part of the pipe fitting at intervals, enabling the pressed areas not to be deformed, and performing the process of flaring on the non-pressed areas in a grading way.
6. The flaring device of claim 4, wherein the swaging punch connecting sleeve and the resetting connecting sleeve are guided by a copper guide plate;
a copper guide plate is adopted for guiding between the material pressing punch and the flaring punch;
the material pressing punch is connected to the material pressing punch connecting sleeve through a bolt, the reaming punch is connected to the rear seat plate through a bolt, the reset connecting sleeve is connected to the rear seat plate through a bolt, and the reset stop block is connected to the reset connecting sleeve through a bolt;
the pressing punch head and the flaring punch head can slide relatively;
the material pressing punch connecting sleeve and the resetting connecting sleeve can slide relatively.
7. The flaring device according to claim 4, characterized in that the flaring device adopts a 'secondary flaring' process, firstly performs the first flaring on the connecting end part of the tubular part, then performs the second flaring on the connecting end part of the tubular part, and disperses the free deformation of the integral flaring of the end part of the pipe fitting into the free deformation of a plurality of small sections in a secondary combined flaring manner to ensure the precision of the 'bell mouth' contour line size of the end part of the pipe fitting.
8. The flaring device of claim 4, wherein said flaring device is capable of better developing the local plastic deformability of the material during flaring, and better developing the plasticity of the material itself, without an intermediate annealing process, to obtain a final part having a "bell mouth" configuration of the outer contour of the desired part.
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| CN202010219042.XA CN113441599B (en) | 2020-03-25 | 2020-03-25 | Hydraulic forming and flaring combined process and device for tubular part |
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| CN202010219042.XA CN113441599B (en) | 2020-03-25 | 2020-03-25 | Hydraulic forming and flaring combined process and device for tubular part |
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| CN113441599A CN113441599A (en) | 2021-09-28 |
| CN113441599B true CN113441599B (en) | 2023-02-14 |
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| CN114346070A (en) * | 2021-12-29 | 2022-04-15 | 宁波信泰机械有限公司 | Partition forming method for inner plate of automobile stand column |
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| JPH0650490A (en) * | 1992-06-25 | 1994-02-22 | Toyo Plast Seiko Kk | Method of branching and connecting plastic pipe and device used therefor |
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| CN113441599A (en) | 2021-09-28 |
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