CN114871324A - A kind of steel tube bulging device and bulging method - Google Patents

Abstract

The invention discloses a steel pipe bulging device and a bulging method, comprising a bulging mold closed by an upper mold and a lower mold and a bulging mechanism; a fixed mold cavity for accommodating the middle of a steel pipe is formed in the bulging mold , a first accommodating space located on the first end side of the fixed mold cavity and a second accommodating space located on the second end side of the fixed mold cavity. A bulging die cavity for accommodating the corresponding end of the steel pipe is formed on the movable block assembly; the bulging mechanism includes a first blocking mechanism arranged on the first end side of the bulging die, and a bulging die formed on the second end of the bulging die. The second blocking mechanism on both ends and the injection channel formed on the first blocking mechanism and/or the second blocking mechanism for injecting high-pressure liquid; the first blocking mechanism and the second blocking mechanism They all include a movable push block arranged on the outer side of the corresponding movable push block assembly, a sealing punch arranged on the movable push block, and a driving device connected with the movable push block.

Description

A kind of steel tube bulging device and bulging method

technical field

The application relates to the technical field of steel pipe forming equipment, and in particular, to a steel pipe bulging device and a bulging method.

Background technique

At present, the bulging of steel pipes is often realized by means of bulging molds and high-pressure liquids. When bulging the end of the steel pipe, a fixed-length mold is usually used. After the steel pipe is placed in the cavity of the bulging mold, the ends of the steel pipe are sealed by a sealing punch, and then high-pressure injection is injected into the steel pipe. Pressure liquid, the use of liquid pressure to shape. However, if the elongation required for pipe expansion is greater than the elongation of the steel pipe wall, the steel pipe will crack and cannot be formed.

SUMMARY OF THE INVENTION

In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present application is to provide a bulging device and a bulging method that can reduce the probability of a steel pipe being burst and cracked.

In order to solve the above-mentioned technical problems, the present application provides a steel pipe bulging device, including a bulging mold closed by an upper mold and a lower mold, and a bulging mechanism; a fixed mold for accommodating the middle of the steel pipe is formed in the bulging mold. A cavity, a movable block assembly located on both ends of the fixed mold cavity, and a bulging mold cavity for accommodating the corresponding end of the steel pipe is formed on the movable block assembly; One end side is used to block the first end of the steel pipe, and the second block mechanism is formed on the second end of the bulging die to block the second end of the steel pipe. On the first blocking mechanism and/or the second blocking mechanism and used for injecting high-pressure liquid into the injection channel into the steel pipe, the first blocking mechanism and the second blocking mechanism are respectively used for compressing the two pipes. Describe the active block component.

Further, the first blocking mechanism and the second blocking mechanism include a movable push block arranged on the outside of the corresponding movable block assembly, a sealing punch arranged on the movable push block, and a drive device connected with the movable push block. and the driving device is used to drive the movable push block to move toward the fixed mold cavity to axially compress the movable block assembly, and the movable push block drives the sealing punch to seal the end of the steel pipe.

Further, the movable block-in assembly includes a self-recoverable compression assembly disposed in the corresponding accommodating space and a sliding assembly slidably fitted in the corresponding accommodating space and located outside the compression assembly, and the sliding assembly is located in the corresponding accommodating space. The compression assembly is pressed inwardly under the thrust of the movable push block.

Further, the compression assembly includes a number of moving plates that are sleeved layer by layer from the inside to the outside and a self-recovery component located between each adjacent two moving plates to automatically reset each moving plate; There is a predetermined compression distance between the two adjacent moving plates when they are not pressed by the sliding component, and the compressed distance between each adjacent two moving plates is gradually reduced under the pressure of the sliding component until the moving plates are stacked together.

Further, the first end side position of the lower mold has a first lower accommodating groove formed by a downward depression, and the second end side position of the lower mold has a second lower chamber formed by a downward depression. The first lower accommodating groove and the second lower accommodating groove respectively penetrate the lower mold in opposite directions, and the first lower accommodating groove and the second lower accommodating groove are both provided with lower moving parts. A first upper accommodating groove is formed at the position of the lower end face of the upper mold corresponding to the first lower accommodating groove, and the lower end face of the upper mold corresponds to the first lower accommodating groove. A second upper accommodating groove is formed at the position of the two lower accommodating grooves, and an upper movable block is arranged in the first upper accommodating groove and the second upper accommodating groove;

The first lower accommodating groove and the first upper accommodating groove form the first accommodating space in the mold-closed state, and the second lower accommodating groove and the second upper accommodating groove form the first accommodating space in the mold-closed state. the second accommodating space; the lower movable insertion block in the first lower accommodating slot and the upper movable insertion block in the first upper accommodating slot form a movable insertion block located in the first accommodating space in the clamping state. In the block assembly, the lower movable block in the second lower accommodating slot and the upper movable block in the second upper accommodating groove form a movable block assembly located in the second accommodating space in a clamping state.

Further, a lower fixed cavity is formed on the upper end surface of the lower mold at a position between the first lower accommodating groove and the second lower accommodating groove, and two ends of the lower fixed cavity are respectively The first lower accommodating groove and the second lower accommodating groove are in communication; the lower end surface of the upper mold is formed with an upper fixing groove at a position between the first upper accommodating groove and the second upper accommodating groove Mould cavity, two ends of the upper fixed mould cavity are respectively connected with the first upper accommodating groove and the second upper accommodating groove; the lower fixed mould cavity and the upper fixed mould cavity are formed in the clamping state. Fixed cavity.

Further, the lower movable insertion block includes a lower sliding block disposed in the corresponding lower accommodating groove and a lower compression portion disposed between the lower sliding block and the lower fixed cavity, and the lower sliding block can be fixed toward the fixed cavity. The mold cavity slides and compresses the lower compression part; the upper movable block includes an upper sliding block arranged in the corresponding upper accommodating groove and an upper compression part arranged between the upper sliding block and the upper fixed cavity, The upper sliding block can slide toward the fixed mold cavity and compress the upper compression part; the lower sliding block and the upper sliding block form the sliding assembly in the clamping state, and the lower compression part and the upper compression part are in the closed state. The compression assembly is formed in a mold state.

Further, the lower compression part includes a plurality of lower moving plates located between the lower sliding block and the lower fixed cavity, and a first self-recovery element located between every two adjacent lower moving plates, each adjacent two lower moving plates. There are lower compression gaps between the lower moving plates; the upper compression part includes a plurality of upper moving plates located between the upper sliding block and the upper fixed cavity and a second self-moving plate located between every two adjacent upper moving plates. Restoring element, there is an upper compression gap between each adjacent two upper moving plates; the upper moving plate and the lower moving plate form the moving plate in the clamping state, the first self-recovery element and the second self-recovery element The restoring element forms the self-healing part in a closed state.

Further, the first self-recovery element is a first return spring, one end of the first return spring is pressed against the lower sliding block, and the other end is pressed against the lower accommodating groove after passing through each lower moving plate in sequence. On the inner side wall of the groove, the lower sliding block is connected to the adjacent lower moving plate; the second self-recovery element is a second return spring, and one end of the second return spring is pressed against the upper sliding block , the other end passes through each upper moving plate in sequence and then presses against the inner groove wall of the upper accommodating groove, and the upper sliding block is connected to the adjacent upper moving plate.

Further, the lower moving plate includes a lower stacking plate, a first nesting groove formed on the inner side of the lower stacking plate, and a first nesting block formed on the outer side of the lower stacking plate, the first nesting groove The size of the slot is smaller than the size of the slot; the first nesting block has a first slug embedded in the first nesting slot and is connected between the first slug and the lower laminated board and The first connecting portion movably penetrates through the notch of the first nesting groove, the thickness of the first inserting head is smaller than the depth of the first nesting groove, and the thickness of the first connecting portion is greater than that of the first connecting portion. Describe the depth of the notch of the first nested groove;

The upper moving plate includes an upper stacking plate, a second nesting groove formed on the inner side of the upper stacking plate, and a second nesting block formed on the outer side of the upper stacking plate, the notch of the second nesting groove is The size is smaller than the size in the groove; the second nesting block has a second insert head embedded in the second nesting groove and is connected between the second insert head and the upper laminated plate and is movably penetrated In the second connecting portion at the notch of the second nesting groove, the thickness of the second insert head is smaller than the depth of the second nesting groove, and the thickness of the second connecting portion is greater than that of the second nesting groove. The depth of the slot for nested slots.

Further, the lower laminated board includes a first lower side board and a second lower side board that are located on the same plane and spaced apart from each other, and the outer sides of the first lower side board and the second lower side board respectively extend outward to form a lower side board. The extension plate, the outer ends of the two lower extension plates are connected with the lower connection plate, the two ends of the lower connection plate respectively protrude from the outer facades of the two lower extension plates to form two lower protrusions, the two lower extension plates and The lower connecting plate is enclosed to form the first nesting groove; the space between the first lower side plate and the second lower side plate forms the notch of the first nesting groove, and the two lower extending plates The inner façades form the two side walls of the first nesting slot, the outer façades of the two lower extension plates form the first connecting portion, and the inner side of the lower connecting plate forms the first nesting portion. The groove bottom wall of the sleeve groove, the outer side surface of the lower connecting plate and the two lower protrusions form the first embedding head of the first nesting block;

The upper laminated board includes a first upper side board and a second upper side board which are located on the same plane and spaced apart from each other, and the outer sides of the first upper side board and the second upper side board respectively extend outward to form an upper extension board , the outer ends of the two upper extension plates are connected with an upper connecting plate, and the two ends of the upper connecting plate respectively protrude from the outer facades of the two upper extending plates to form two upper protrusions, the two upper extending plates and the upper The connecting plate is enclosed to form the second nesting groove; the space between the first upper side plate and the second upper side plate forms the notch of the second nesting groove, and the two upper extending plates have The inner façades form the two side walls of the second nesting groove, the outer façades of the two upper extension plates form the second connecting portion, and the inner sides of the upper connecting plate form the second nesting The bottom wall of the groove, the outer side surface of the upper connecting plate and the two upper protrusions form the second inserting head of the second nesting block.

The present application also provides a method for bulging a steel pipe, using the above-mentioned steel pipe account device to bulge a steel pipe, comprising the following steps:

S1, closing the upper mold and the lower mold, so that the middle part of the steel pipe to be expanded is located in the fixed mold cavity, and the two ends of the steel pipe to be expanded are located in the two bulging mold cavities respectively;

S2. Make the driving devices of the first blocking mechanism and the second blocking mechanism drive the two movable push blocks to move toward the fixed mold cavity respectively, so that the sealing punches of the first blocking mechanism and the second blocking mechanism are pushed in respectively Both ends of the steel pipe to seal both ends of the steel pipe;

S3, inject high-pressure liquid into the steel pipe through the injection channel of the first blocking mechanism and/or the second blocking mechanism, and at the same time, the two driving devices continue to drive the two movable push blocks to compress the two movable block assemblies inward, and The two sealing punches compress the two ends of the steel pipe respectively and feed the bulging part of the steel pipe;

S4. The two driving devices respectively drive the two movable push blocks to reset, so that the two sealing punches are reset with the two movable push blocks respectively, the two movable block-in assemblies are reset, and the upper die and the lower die are separated to take out the steel pipe that has completed the bulging.

Owing to adopting the above-mentioned technical scheme, the technical effect of the present invention is:

When the steel pipe bulging device of the present invention is used to bulge the steel pipe, after the upper and lower molds are closed, the middle of the steel pipe is located in the fixed mold cavity, and the two ends of the steel pipe are located in the two bulging mold cavities respectively. The first blocking mechanism and the second blocking mechanism block the two ends of the steel pipe respectively, and then inject high-pressure liquid into the steel pipe through the injection pipe to bulge the two ends of the steel pipe. During the bulging process, the first sealing mechanism The blocking mechanism and the second blocking mechanism respectively compress the two movable block-in components, and also compress the steel pipe, which has the effect of feeding material while bulging, and can reduce the probability of the steel pipe being swelled during the bulging process.

Description of drawings

The drawings described herein are used to provide further understanding of the present application and constitute a part of the present application. The schematic embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation of the present application. In the attached image:

1 is a top view of a preferred embodiment of a steel tube bulging device of the present invention;

Fig. 2 is the A-A sectional view of Fig. 1;

Fig. 3 is the structural representation of the lower movable block in a steel pipe bulging device of the present invention;

Fig. 4 is an enlarged view of a in Fig. 3;

5 is a schematic structural diagram of an upper movable block in a steel tube bulging device of the present invention;

Fig. 6 is the enlarged view of b in Fig. 5;

7 is a schematic structural diagram of a lower moving plate in a steel tube bulging device of the present invention;

8 is a schematic structural diagram of an upper moving plate in a steel tube bulging device of the present invention;

9 is a schematic structural diagram of a lower die in a steel tube bulging device of the present invention;

10 is a schematic structural diagram of an upper die in a steel tube bulging device of the present invention;

Fig. 11 is the structural representation of the steel pipe to be expanded;

Fig. 12 is a schematic structural diagram of the steel pipe after bulging is completed.

Reference numerals in the drawings include:

1. Bulging mold; 2. First blocking mechanism; 3. Second blocking mechanism; 11. Upper mold; 12. Lower mold; 13. Fixed cavity; 14. First accommodation space; 15. Second accommodation space; 4, movable block assembly; 41, bulging die cavity; 21, first movable push block; 22, first sealing punch; 23, injection channel; 24, first drive device; 31, second movable pusher block; 32, the second sealing punch; 33, the second driving device; 141, the first lower accommodating groove; 151, the second lower accommodating groove; 142, the first upper accommodating groove; 152, the second upper accommodating groove slot; 42, lower movable block; 411, lower bulging cavity; 43, upper movable block; 412, upper bulging cavity; 131, lower fixed cavity; 132, upper fixed cavity; 421, lower Sliding block; 422, lower compression part; 431, upper sliding block; 432, upper compression part; 4221, lower moving plate; 4222, first self-recovery element; 4321, upper moving plate; 4322, second self-recovery element; 42211 42212, the first nesting slot; 42213, the first nesting block; 422131, the first embedding head; 422132, the first connecting part; 43211, the upper stacking plate; 432131, the second inserting head; 432132, the second connecting part; 422111, the first lower side plate; 422112, the second lower side plate; 422113, the lower extension plate; 422114, the lower connecting plate; 432112, the second upper side plate; 432113, the upper extension plate; 432114, the upper connecting plate; 4211, the third nesting groove; 4311, the fourth nesting groove; 121, the lower guide groove; 4212, the first lower guide protrusion; 42214, the second lower guide protrusion; 4213, the lower step; 122, the lower escape groove; 111, the upper guide groove; 4312, the first upper guide protrusion; 43214, the second upper Guide protrusion; 4313, upper step; 112, upper escape groove; 231, first channel; 232, second channel.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below with reference to the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention.

As shown in FIG. 1 and FIG. 2 , an embodiment of a steel tube bulging device of the present invention includes a bulging die 1 and a bulging mechanism. The bulging mold 1 is formed by closing an upper mold 11 and a lower mold 12. A fixed mold cavity 13, a first accommodating space 14 and a second accommodating space 15 are formed in the bulging mold 1. The fixed mold cavity 13 For accommodating the middle of the steel pipe, the first accommodating space 14 is located on the first end side of the fixed mold cavity 13 , the second accommodating space 15 is located on the second end side of the fixed mold cavity 13 , and both ends of the fixed mold cavity 13 There is a movable block-in assembly 4 on the side, and the two movable block-in assemblies 4 are respectively located in the first accommodating space 14 and the second accommodating space 15, and a bulging mold cavity 41 is formed on the movable block-in assembly 4, so The bulging mold cavity 41 is used for accommodating the end of the steel pipe, and the size of the bulging mold cavity is adapted to the size of the bulging mold cavity. The bulging mechanism includes a first blocking mechanism 2 provided on the first end side of the bulging die 1 for blocking the first end of the steel pipe, and a first blocking mechanism 2 formed on the second end side of the bulging die 1 for blocking the first end of the steel pipe. a second blocking mechanism 3 for blocking the second end of the steel pipe, and an injection channel 5 formed on the first blocking mechanism 2 and/or the second blocking mechanism 3 and used for injecting high-pressure liquid into the steel pipe, The first blocking mechanism 2 and the second blocking mechanism 3 are respectively used for compressing the two movable block-in assemblies.

A first lower accommodating groove 141 is formed on the lower mold 12 , the first lower accommodating groove 141 is located at the first end side of the lower mold 12 , and the first lower accommodating groove 141 is the upper end of the lower mold 12 The lower mold 12 is also formed with a second lower accommodating groove 151, the second lower accommodating groove 151 is located on the second end side of the lower mold 12, and the second lower accommodating groove 151 is formed by the upper end of the lower mold 12 being recessed downward, and the first lower accommodating groove 141 and the second lower accommodating groove 151 respectively penetrate the lower mold 12 in opposite directions (opposite directions). A first upper accommodating groove 142 is formed on the lower end surface of the upper mold 11 , and the first upper accommodating groove 142 corresponds to the position of the first lower accommodating groove 141 . 142 is adapted to the first lower accommodating groove 141, the lower end surface of the upper mold 11 is formed with a second upper accommodating groove 152, and the second upper accommodating groove 152 corresponds to the second lower accommodating groove 152. At the position of the accommodating groove 151 , the second upper accommodating groove 152 is matched with the second lower accommodating groove 151 . When the upper mold 11 and the lower mold 12 are in the clamping state, the first lower accommodating groove 141 and the first upper accommodating groove 142 form the first accommodating space 14 , the second lower accommodating groove 151 and The second upper accommodating groove 152 forms the second accommodating space 15 .

Both the first lower accommodating groove 141 and the second lower accommodating groove 151 are provided with a lower movable insertion block 42, and a lower bulging cavity 411 is formed on the lower movable insertion block 42; An upper movable insertion block 43 is provided in the setting groove 142 and the second upper accommodating groove 152 , and an upper bulging cavity 412 is formed on the upper movable insertion block 43 . When the upper mold 11 and the lower mold 12 are in the clamping state, the lower movable insertion block 42 in the first lower accommodating groove 141 and the upper movable insertion block 43 in the first upper accommodating groove 142 form a position in the first lower accommodating groove 141. A movable block assembly 4 in the accommodating space 14, the lower movable block 42 in the second lower accommodating groove 151 and the upper movable block 43 in the second upper accommodating groove 152 form the second accommodating block 43 In the movable block assembly 4 in the space 15, the lower bulging cavity 411 on the lower movable block 42 and the upper bulging cavity 412 on the upper movable block 43 in the first accommodation space 14 form a bulge The mold cavity 41 , the lower bulging mold cavity 411 on the lower movable block 42 and the upper bulging mold cavity 412 on the upper movable block in the second accommodating space 15 also form the bulging mold cavity 41 .

A lower fixed cavity 131 is formed on the upper end surface of the lower mold 12 , and the lower fixed cavity 131 is located between the first lower accommodating groove 141 and the second lower accommodating groove 151 . One end of the cavity 131 communicates with the first lower accommodating groove 141 , and the other end of the lower fixing cavity 131 communicates with the second lower accommodating groove 151 . An upper fixed cavity 132 is formed on the lower end surface of the upper mold 11 , and the upper fixed cavity 132 is located between the first upper accommodating groove 142 and the second upper accommodating groove 152 . One end of the cavity 132 communicates with the first upper accommodating groove 142, and the other end of the upper fixed cavity 132 communicates with the second upper accommodating groove 152; In the mold state, the lower fixed cavity 131 and the upper fixed cavity 132 form the fixed cavity 13 .

The movable block assembly 4 includes a compression assembly and a sliding assembly. The compression assembly is arranged in the corresponding accommodation space, that is, the compression assembly on the movable block assembly 4 located in the first accommodation space 14 is located in the first accommodation space 14. Inside, the compression assembly on the movable block assembly 4 located in the second accommodating space 15 is located in the second accommodating space 15 . The compression assembly is in a compressed state and can be self-recovered after the pressure it receives disappears. In the first accommodating space 14 , the sliding components on the movable block assembly 4 located in the second accommodating space 15 are slidably fitted in the second accommodating space 15 . The sliding component is located outside the compression component (the side facing away from the fixed mold cavity 13, in the subsequent description, the side facing away from the fixed mold cavity 13 is taken as the outside, and vice versa). The sliding assembly can slide inwardly and hold the compression assembly.

The compression assembly includes several moving plates and a self-recovery part, the several moving plates are sleeved layer by layer from the inside to the outside, the self-recovery part is located between every two adjacent moving plates, and the self-recovery part is used to make the Each moving board resets automatically. In the state of not being pressed by the sliding assembly, there is a predetermined first compression distance between every two adjacent moving plates, and the sum of all the first compression distances is adapted to the size of the material to be supplemented during the steel pipe bulging process . In yet another embodiment, a second compression distance is provided between the outermost moving plate and the sliding assembly, a third compression distance is provided between the innermost moving plate and the inner side wall of the corresponding accommodation space, and the second compression distance , the sum of the third compression distance and all the first compression distances is adapted to the size of the material needed to be supplemented during the sensory bulging process. Under the pressure of the sliding component, the first compression distance gradually decreases until the moving plates are stacked together. In this way, during the bulging process of both ends of the steel pipe, the ends of the steel pipe are supported by several moving plates, and the distributed first compression distances can divide the distance between the sliding component and the fixed mold cavity 13 into several parts to prevent the steel pipe from sliding The distance between the component and the fixed mold cavity 13 is too large, which leads to the problem of the steel pipe being burst. In the process of gradually pushing the sliding assembly inward, the sliding assembly pushes the compression assembly inward, so that the axial length of the movable block assembly 4 can be gradually reduced, and finally it is adapted to the length of the steel pipe end to be bulged to complete the Tube bulging.

As shown in FIG. 3 and FIG. 5 , the lower movable entry block 42 includes a lower sliding block 421 and a lower compression part 422 , and the lower sliding block 421 is arranged in the corresponding lower accommodating groove, that is, located in the first lower accommodating slot. The lower sliding block 421 on the lower movable entry block 42 in the slot 141 is located in the first lower accommodating slot 141, and the lower sliding block 421 on the lower movable entry block 42 located in the second lower accommodating slot 151 is located in the second lower accommodating slot 151. in the accommodating groove 151 . The lower compression part 422 is disposed between the lower sliding block 421 and the lower fixed cavity 131 , and the lower sliding block 421 can slide toward the fixed cavity 13 , that is, the lower sliding block 421 can face the lower fixed cavity 131 Sliding, the lower sliding block 421 is used to compress the lower compression part 422 . The upper movable entry block 43 includes an upper sliding block 431 and an upper compression portion 432 . The upper sliding block 431 is disposed in the corresponding upper accommodating groove, that is, the upper movable entering block 43 located in the first upper accommodating groove 142 The upper sliding block 431 is located in the first upper accommodating groove 142 , and the upper sliding block 431 on the upper movable block 43 located in the second upper accommodating groove 152 is located in the second upper accommodating groove 152 . The upper compression part 432 is disposed between the upper sliding block 431 and the upper fixed cavity 132 , and the upper sliding block 431 can slide toward the fixed cavity 13 , that is, the upper sliding block 431 can slide toward the upper fixed cavity 132 , the upper sliding block 431 is used to compress the upper compression part 432 . When the upper mold 11 and the lower mold 12 are in the clamping state, the lower sliding block 421 and the upper sliding block 431 form the sliding assembly, and the lower compression part 422 and the upper compression part 432 form the compression components.

The lower compression part 422 includes a plurality of lower moving plates 4221 and a first self-recovery element 4222. The plurality of lower moving plates 4221 are located between the lower sliding block 421 and the lower fixed cavity 131. The first self-recovery element The 4222 is located between every two adjacent lower moving plates 4221, and there is a lower compression gap between each adjacent two lower moving plates 4221; the upper compression part 432 includes a plurality of upper moving plates 4321 and a second self-recovery element 4322, The plurality of upper moving plates 4321 are located between the upper sliding block 431 and the upper fixed cavity 132, and the second self-recovery element 4322 is located between every two adjacent upper moving plates 4321, and every two adjacent upper moving plates 4321 Each of the plates 4321 has an upper compression gap. When the upper mold 11 and the lower mold 12 are in the clamping state, the upper moving plate 4321 and the lower moving plate 4221 form the moving plate, the first self-recovery element 4222 and the second self-recovery element 4322 The self-healing part is formed. The upper sliding block 431 can push each upper moving plate 4321 toward the fixed mold cavity 13 in turn, thereby compressing each upper compression gap, and the lower sliding block 421 can sequentially push each lower moving plate 4221 toward the fixed mold cavity 13, thereby compressing each lower compression gap.

As shown in FIG. 4 , the lower moving plate 4221 includes a lower stacking plate 42211, a first nesting groove 42212 and a first nesting block 42213, the first nesting groove 42212 is formed inside the lower stacking plate 42211, The first nesting block 42213 is formed on the outer side of the lower laminated board 42211, the size of the notch of the first nesting groove 42212 is smaller than the size of the inner groove; the first nesting block 42213 has a first inserting head 422131 and a first connecting portion 422132, the first inserting head 422131 is embedded in the first nesting groove 42212, and the first connecting portion 422132 is connected between the first inserting head 422131 and the lower laminate 42211 , the first connecting portion 422132 is movably passed through the notch of the first nesting groove 42212 . The thickness of the first insert head 422131 is smaller than the depth of the first nesting groove 42212 , and the thickness of the first connecting portion 422132 is greater than the depth of the notch of the first nesting groove 42212 . Through the nesting action of the first nesting block 42213 and the first nesting groove 42212, during the outward movement and reset process of the outermost lower moving plate 4221, other lower moving plates 4221 can be driven to move outward and reset in turn.

As shown in FIG. 6 , the upper moving plate 4321 includes an upper stacking plate 43211, a second nesting slot 43212 and a second nesting block 43213, the second nesting slot 43212 is formed inside the upper stacking plate 43211, The second nesting block 43213 is formed on the outer side of the upper laminated board 43211, and the size of the notch of the second nesting groove 43212 is smaller than the size of the inner groove; the second nesting block 43213 has a second inserting head 432131 and a second connecting portion 432132, the second inserting head 432131 is embedded in the second nesting groove 43212, and the second connecting portion 432132 is connected between the second inserting head 432131 and the upper laminated board 43211 , the second connecting portion 432132 is movably passed through the notch of the second nesting groove 43212, the thickness of the second inserting head 432131 is smaller than the depth of the second nesting groove 43212, the second nesting groove 43212 The thickness of the connecting portion 432132 is greater than the depth of the groove of the second nesting groove 43212 . Through the nesting action of the second nesting block 43213 and the second nesting groove 43212, during the outward movement and reset process of the outermost upper moving plate 4321, other upper moving plates 4321 can be driven to move outward and reset in turn.

As shown in FIG. 7 , the lower laminated board 42211 includes a first lower side board 422111 and a second lower side board 422112. The first lower side board 422111 and the second lower side board 422112 are located on the same plane. The first lower side plate 422111 and the second lower side plate 422112 are spaced apart from each other. The outer sides of the first lower side plate 422111 and the second lower side plate 422112 respectively extend outward to form a lower extension plate 422113. The outer ends of the plates 422113 are connected with the lower connecting plate 422114, and the two ends of the lower connecting plate 422114 respectively protrude from the outer surfaces of the two lower extending plates 422113 to form two lower protrusions. The two lower extending plates 422113 and the lower The connecting plate 422114 encloses the first nesting groove 42212; the space between the first lower side plate 422111 and the second lower side plate 422112 forms the notch of the first nesting groove 42212, the The inner elevations of the two lower extension plates 422113 form two side walls of the first nesting groove 42212, the outer elevations of the two lower extension plates 422113 form the first connection portion 422132, and the lower connection plate 422114 The inner side of the lower connecting plate 422114 forms the groove bottom wall of the first nesting groove 42212, and the outer side and the two lower protrusions of the lower connecting plate 422114 form the first inserting head 422131 of the first nesting block 42213.

As shown in FIG. 8 , the upper laminated board 43211 includes a first upper side board 432111 and a second upper side board 432112. The first upper side board 432111 and the second upper side board 432112 are located on the same plane. The first upper side plate 432111 and the second upper side plate 432112 are spaced apart from each other. The outer sides of the first upper side plate 432111 and the second upper side plate 432112 respectively extend outward to form an upper extension plate 432113. The outer ends of the extension plates 432113 are all connected with an upper connecting plate 432114. Both ends of the upper connecting plate 432114 protrude from the outer elevations of the two upper extension plates 432113 to form two upper protrusions. The two upper extension plates 432113 And the upper connecting plate 432114 is enclosed to form the second nesting groove 43212; the space between the first upper side plate 432111 and the second upper side plate 432112 forms the notch of the second nesting groove 43212, The inner elevations of the two upper extension plates 432113 form two side walls of the second nesting groove 43212, and the outer elevations of the two upper extension plates 432113 form the second connecting portion 432132, and the upper connection The inner side of the plate 432114 forms the groove bottom wall of the second nesting groove 43212 , and the outer side and the two upper protrusions of the upper connecting plate 432114 form the second inserting head 432131 of the second nesting block 43213 .

As shown in FIG. 3 , the first self-recovery element 4222 is a first return spring, one end of the first return spring is pressed against the lower sliding block 421, and the other end of the first return spring passes through the lower moving plates 4221 in sequence and then presses against the lower sliding block 421. The lower sliding block 421 is connected to the adjacent lower moving plate 4221. The inner side of the lower sliding block 421 is provided with a third nesting groove 4211. The size of the notch of the sleeve groove 4211 is smaller than the size of the inner groove, and the first embedding head 422131 on the lower moving plate 4221 adjacent to the lower sliding block 421 The first connecting portion 422132 on the lower moving plate 4221 adjacent to the sliding block 421 is movably passed through the notch of the third nesting groove 4211 . After the lower sliding block 421 loses the pressed pressure, the lower sliding block 421 can be pushed outward to reset by the restoring action of the first return spring, and the lower sliding block 421 can pull the lower moving plates 4221 outward in sequence to reset. In other embodiments, the third nesting groove 4211 may not be provided, and the first inserting head 422131 can also be directly fixed on the lower sliding block 421 by bonding or welding. In addition, the first restoring element is not limited to the above-mentioned restoring spring, and the first restoring portion can also be a spring edge disposed between the edges of every two adjacent lower moving plates 4221, for example, located at every two adjacent lower moving plates 4221 The V-shaped spring edges on the edges of both sides can be directly connected by V-shaped spring edges between each adjacent two lower moving plates.

As shown in FIG. 5 , the second self-recovery element 4322 is a second return spring. One end of the second return spring is pressed against the upper sliding block 431 , and the other end of the second return spring passes through the upper moving plates 4321 in sequence and then presses against the upper sliding block 431 . The upper sliding block 431 is connected to the adjacent upper moving plate 4321. The inner side of the upper sliding block 431 is provided with a fourth nesting groove 4311. The size of the notch of the sleeve groove 4311 is smaller than the size of the inside of the groove, and the second embedding head 432131 on the upper moving plate 4321 adjacent to the upper sliding block 431 The second connecting portion 432132 on the upper moving plate 4321 adjacent to the sliding block 431 is movably passed through the slot of the fourth nesting slot 4311 . After the upper sliding block 431 loses the pressed pressure, the upper sliding block 431 can be pushed outward to reset by the reset action of the second return spring, and the upper sliding block 431 can sequentially pull the upper moving plates 4321 outward to reset. In other embodiments, the fourth nesting groove 4311 may not be provided, and the second inserting head 432131 can also be directly fixed on the upper sliding block 431 by bonding or welding. In addition, the second restoring element is not limited to the above-mentioned restoring spring, and the second restoring portion can also be a spring edge disposed between every two adjacent upper moving plates 4321 , for example, located at two sides of every two adjacent upper moving plates 4321 . The V-shaped spring edge on the side edge can be directly connected by the V-shaped spring edge between each adjacent two upper moving plates.

As shown in FIG. 3 , FIG. 4 and FIG. 9 , a lower guide groove 121 is formed on the side walls of the first lower accommodating groove 141 and the second lower accommodating groove 151 , and the lower sliding block 421 A first lower guide protrusion 4212 is formed at a position corresponding to the lower guide groove 121. The first lower guide protrusion 4212 is slidably matched with the lower guide groove 121. A second lower guide protrusion 42214 is formed at a position corresponding to the lower guide groove 121. The upper end of the second lower guide protrusion 42214 is supported on the top wall of the lower guide groove 121. The sliding block 421 has a lower step 4213 , the lower end of the lower moving plate 4221 abuts on the upper side of the lower step 4213 , and the inner side walls of the first lower accommodating slot 141 and the second lower accommodating slot 151 are both provided with There is a lower escape groove 122, the lower escape groove 122 is used to accommodate the inner side end of the corresponding lower step 4213, and the distance between the inner side wall of the lower escape groove 122 and the inner side end of the corresponding lower step 4213 is not less than each steel pipe. The end is a preset compression distance to meet the feeding requirements, that is, the distance between the inner side wall of the lower escape groove 122 and the inner end of the corresponding lower step 4213 is not less than the lower compression part 422 is compressed when the steel pipe bulging is completed. Pitch. Under the restriction of the lower guide groove 121, the lower sliding block 421 and the lower moving plate 4221 are not easily disengaged from the lower mold 12, and the lower guide groove 121 can also play a guiding role, so that the lower sliding block 421 and The lower moving plate 4221 is more stable when moving toward or away from the fixed cavity 13 . It can be understood that, in other embodiments, the lower step 4213 can also be omitted, and the size of the lower moving plate 4221 can be changed so that the lower end of the lower moving plate 4221 directly abuts on the lower side wall of the corresponding lower accommodating slot.

As shown in FIG. 5 , FIG. 6 and FIG. 10 , upper guide grooves 111 are formed on the first upper accommodating groove 142 and the side wall of the second upper accommodating groove, and the upper sliding block 431 is connected with A first upper guide protrusion 4312 is formed at a position corresponding to the upper guide groove 111 . The first upper guide protrusion 4312 is slidingly matched with the upper guide groove 111 . A second upper guide protrusion 43214 is formed at a position corresponding to the upper guide groove 111 , the second upper guide protrusion 43214 is supported on the bottom wall of the upper guide groove 111 , and the upper sliding block 431 is There is an upper step 4313, the upper end of the upper moving plate 4321 abuts the lower side of the upper step 4313, and the inner side walls of the first upper accommodating groove 142 and the second upper accommodating groove 152 are provided with upper avoidance grooves 112, the upper avoidance groove 112 is used to accommodate the inner side end of the corresponding upper step 4313, and the distance between the inner side wall of the upper avoidance groove 112 and the inner side end of the corresponding upper step 4313 is not less than each end of the steel pipe to meet the compensation requirements. The preset compression distance required by the material, that is, the distance between the inner side wall of the upper escape groove 112 and the inner end of the corresponding upper step 4313 is not less than the distance at which the upper compression portion 432 is compressed when the steel pipe bulging is completed. The upper guide groove 111 can prevent the upper sliding block 431 and the upper moving plate 4321 from coming out of the upper die 13 downward, and the upper guiding groove 111 can play a guiding role, so that the upper sliding block 431 and the upper moving plate 4321 are facing or deviating from each other. The fixed cavity 13 is more stable when moving. It can be understood that in other embodiments, the upper step 4313 can also be omitted, and the size of the upper moving plate 4321 can be changed, so that the upper end of the upper moving plate 4321 directly abuts on the upper side wall of the corresponding upper accommodating slot.

As shown in FIG. 2 , the first blocking mechanism 2 includes a first movable push block 21 disposed outside the movable block assembly 4 on the first end side, and a first movable push block 21 disposed inside the first movable push block 21 . The punch 22 and the first drive device 24 are sealed. The first drive device 24 is connected with the first movable push block 21 , the first drive device 24 is used to drive the first movable push block 21 to move toward the fixed mold cavity 13 , and the first movable push block 21 drives the first movable push block 21 . The sealing punch 22 seals one end of the steel pipe and axially compresses the corresponding movable block assembly 4, and the sliding assembly provided on the first end side presses the inwardly under the thrust of the first movable push block. Compressed components. The first movable push block 21 can axially compress the corresponding movable block assembly 4, and at the same time, the first sealing punch 22 can also move with the first movable push block 21 and compress the steel pipe, so that the steel pipe can be compressed during the bulging process. act as a supplement. The first driving device 24 is a hydraulic cylinder. In other embodiments, the first driving device 24 may also be a cylinder or a push rod motor.

The second blocking mechanism 3 includes a second movable push block 31 disposed outside the movable block assembly 4 on the second end side, a second sealing punch 32 disposed inside the second movable push block 31 , and a second movable push block 32 . Two driving devices 33, the second driving device 33 is connected with the second movable push block 31, the second driving device 33 is used to drive the second movable push block 31 to move towards the fixed mold cavity 13, the second movable push block 31 The block 31 drives the second sealing punch 32 to seal the other end of the steel pipe and axially compress the corresponding movable block assembly 4. The sliding assembly located on the second end side is under the thrust of the second movable push block The compression assembly is compressed inwardly. The second movable push block 31 can axially compress the corresponding movable block assembly 4, and at the same time, the second sealing punch 32 can also move with the second movable push block 31 and compress the steel pipe, so that the steel pipe can be compressed during the bulging process. act as a supplement. The second driving device 33 is a hydraulic cylinder, and in other embodiments, the second driving device 33 may also be an air cylinder or a push rod motor.

The injection channel 5 can be formed on the first movable push block 21 and the first sealing punch 22 or formed on the second movable push block 31 and the second sealing punch 32, and can also be formed on the first movable push block 31 and the second sealing punch 32. The injection channel is formed on a movable push block 21 , the first sealing punch 22 and the second movable push block 31 and the second sealing punch 32 . In this specific embodiment, please continue to refer to FIG. 2 , the injection channel 5 is formed on the first movable push block 21 and the first sealing punch 22 , and includes a first hole 51 and a second hole 52 . A hole 51 is located in the first movable push block 21, the second hole 52 is located in the first sealing punch 22, and the first end of the first hole 51 penetrates the first movable push block 21 in one direction, The second end of the first hole 51 communicates with the first end of the second hole 52 , and the second end of the second hole 232 passes through the first sealing punch 22 along the length direction of the first sealing punch 22 . The punch 22 is sealed, and the high-pressure liquid is pumped into the steel pipe through the first hole 231 and the second hole 232 to bulge the end of the steel pipe.

Embodiment 2

A steel pipe bulging method, which utilizes the steel pipe bulging device described in Embodiment 1 to bulge a steel pipe, specifically comprising the following steps:

S1. Close the upper die 11 and the lower die 12, so that the middle part of the steel pipe to be expanded (please refer to FIG. 11) is located in the fixed cavity 13, and the two ends of the steel pipe to be expanded are respectively It is located in the two bulging mold cavities 41 .

The steel pipe to be bulged is placed on the lower die 12 , the two ends of the steel pipe are located in the lower bulging cavities 411 on the two lower movable blocks 42 respectively, and the middle part of the steel pipe is located in the lower fixed cavity on the plate of the lower die 12 . 131; the upper mold 11 and the lower mold 12 are closed, the upper fixed cavity 132 and the lower fixed cavity 131 form the fixed cavity 13, and the upper bulging cavity 412 and the lower bulging cavity 411 constitute the bulging cavity 41.

S2, make the first driving device 24 of the first blocking mechanism 2 and the second driving device 33 of the second blocking mechanism 3 respectively drive the first movable push block 21 and the second movable push block 31 to move toward the fixed mold cavity 13, The first sealing punch 22 of the first blocking mechanism 2 and the second sealing punch 33 of the second blocking mechanism 3 are respectively pushed into both ends of the steel pipe to seal both ends of the steel pipe.

S3. Inject high-pressure liquid into the steel pipe through the injection channel 5 of the first blocking mechanism 2, and at the same time, the first driving device 24 and the second driving device 33 continue to drive the first movable push block 21 and the second movable push block 31 respectively. The two movable block assemblies are compressed inside, and the first sealing punch 22 and the second sealing punch 33 respectively compress the two ends of the steel pipe and fill the bulging part of the steel pipe. In other embodiments, the first blocking mechanism 2 is not provided with an injection channel, and when only the second blocking mechanism 3 is provided with an injection channel, the high-pressure liquid is injected into the steel pipe through the injection channel on the second blocking mechanism 3 . When both the first plugging mechanism 2 and the second plugging mechanism 3 are provided with an injection channel, injection into the steel pipe can be done simultaneously through the injection channel on the first plugging mechanism 2 and the injection channel on the second plugging mechanism 3 high pressure liquid.

Specifically, the high-pressure liquid is injected into the steel pipe through the first hole 51 and the second hole 52 to gradually bulge the steel pipe, and at the same time, the two hydraulic cylinders are controlled to gradually drive the first movable push block 21 and the second movable push block 31 toward the fixed direction. The mold cavity 13 moves, the first movable push block 21 gradually pushes the corresponding upper sliding block 431 and the lower sliding block 421 toward the fixed mold cavity 13, the upper sliding block 431 compresses the upper compression part 432, and the lower sliding block 421 compresses the lower compression part 422, The first sealing punch 22 compresses one end of the steel pipe. The second movable push block 31 gradually pushes the corresponding upper sliding block 431 and the lower sliding block 421 toward the fixed mold cavity 13 , the upper sliding block 431 compresses the upper compression part 432 , the lower sliding block 421 compresses the lower compression part 422 , and the second sealing punch 32 Compress the other end of the steel pipe. In order to supplement the bulging position at both ends of the steel pipe.

S4. The first driving device 24 and the second driving device 33 respectively drive the first movable push block 21 and the second movable push block 31 to reset, so that the first sealing punch 22 and the second sealing punch 33 move with the first The push block 21 and the second movable push block 31 are reset, the two movable block-in components are reset, and the upper die 11 and the lower die 12 are separated to take out the bulging steel pipe (please refer to Fig. 12).

Specifically, after the steel pipe bulging is completed, the two hydraulic cylinders are controlled to drive the first movable push block 21 and the second movable push block 31 to reset respectively, the first sealing punch 22 is reset with the first movable push block 21, and the second sealing punch The head 32 is reset with the second movable push block 31, the corresponding lower sliding block 421 and the lower compression part 422 are reset under the action of the first return spring, the upper slider and the upper compression part 432 are reset under the action of the second return spring, Finally, the upper die 11 and the lower die 12 are separated, and the bulged steel pipe is taken out from the lower die 12 to complete the bulging of both ends of the steel pipe.

During the bulging process, the two hydraulic cylinders drive the first movable push block 21 and the second movable push block 31 to move toward the fixed mold cavity 13 respectively, and the first movable push block 21 and the second movable push block 31 respectively compress the corresponding movable push block 21 and the second movable push block 31. The block assembly 4 has the effect of feeding material while bulging, which can reduce the probability of the steel pipe being swelled during the bulging process; during the bulging process, each upper moving plate 4321 and each lower moving plate 4221 can always keep Support the pipe wall of the steel pipe, so that the part of the steel pipe between the sliding assembly and the sliding assembly will not be swelled because it is not supported for a long distance. After the steel tube that has been bulged is taken out, when the two hydraulic cylinders drive the first movable push block 21 and the second movable push block 31 to reset respectively, under the reset action of the first self-recovery element 4222 and the second self-recovery element 4322, the Each upper sliding block 431, each lower sliding block 421, each upper moving plate 4321 and each lower moving plate 4221 can be automatically reset, which is very convenient to use.

The above examples only represent the preferred embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as limiting the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (12)

1. The utility model provides a steel pipe bulging device which characterized in that: comprises an expansion die formed by closing an upper die and a lower die and an expansion mechanism; a fixed die cavity for accommodating the middle part of the steel pipe and movable inlet block assemblies positioned at two end sides of the fixed die cavity are formed in the bulging die, and bulging die cavities for accommodating corresponding end parts of the steel pipe are formed in the movable inlet block assemblies; the bulging mechanism comprises a first plugging mechanism arranged on the first end side of the bulging die and used for plugging the first end of the steel pipe, a second plugging mechanism formed on the second end side of the bulging die and used for plugging the second end of the steel pipe, and an injection channel formed on the first plugging mechanism and/or the second plugging mechanism and used for injecting high-pressure liquid into the steel pipe, wherein the first plugging mechanism and the second plugging mechanism are respectively used for compressing the two movable insert assemblies.

2. A steel pipe bulging apparatus according to claim 1, wherein: the first blocking mechanism and the second blocking mechanism respectively comprise a movable push block arranged on the outer side of the corresponding movable insert assembly, a sealing punch arranged on the movable push block and a driving device connected with the movable push block, the driving device is used for driving the movable push block to move towards the direction of the fixed die cavity so as to axially compress the movable insert assembly, and the movable push block drives the sealing punch to seal the end part of the steel pipe.

3. A steel pipe bulging apparatus according to claim 1, wherein: the movable insert assembly comprises a compression assembly which is arranged in the corresponding accommodating space and can be recovered and a sliding assembly which is in sliding fit with the corresponding accommodating space and is positioned on the outer side of the compression assembly, and the sliding assembly is pressed inwards under the thrust of the movable push block to hold the compression assembly.

4. A steel pipe bulging apparatus according to claim 2, wherein: the compression assembly comprises a plurality of moving plates which are sleeved layer by layer from inside to outside and a self-recovery part which is positioned between every two adjacent moving plates so as to ensure that each moving plate automatically resets; and each two adjacent moving plates have a preset compression space when not pressed and held by the sliding assembly, and the compression space between each two adjacent moving plates is gradually reduced under the pressing and holding of the sliding assembly until the moving plates are abutted and laminated together.

5. A steel pipe bulging apparatus according to claim 3, wherein: a first lower accommodating groove formed by downward depression is formed in the position of the first end side of the lower die, a second lower accommodating groove formed by downward depression is formed in the position of the second end side of the lower die, the first lower accommodating groove and the second lower accommodating groove respectively penetrate through the lower die in opposite directions, and lower movable insert blocks are arranged in the first lower accommodating groove and the second lower accommodating groove; a first upper accommodating groove matched with the lower end surface of the upper die is formed at a position corresponding to the first lower accommodating groove, a second upper accommodating groove matched with the lower end surface of the upper die is formed at a position corresponding to the second lower accommodating groove, and upper movable inlet blocks are arranged in the first upper accommodating groove and the second upper accommodating groove;

the first lower accommodating groove and the first upper accommodating groove form the first accommodating space in a die-closed state, and the second lower accommodating groove and the second upper accommodating groove form the second accommodating space in the die-closed state; the lower movable insert block in the first lower accommodating groove and the upper movable insert block in the first upper accommodating groove form a movable insert block assembly positioned in the first accommodating space in a die-closing state, and the lower movable insert block in the second lower accommodating groove and the upper movable insert block in the second upper accommodating groove form a movable insert block assembly positioned in the second accommodating space in a die-closing state.

6. The steel pipe bulging apparatus according to claim 4, wherein: a lower fixed cavity is formed in the upper end face of the lower die and is positioned between the first lower accommodating groove and the second lower accommodating groove, and two ends of the lower fixed cavity are respectively communicated with the first lower accommodating groove and the second lower accommodating groove; an upper fixed cavity is formed in the lower end face of the upper die and located between the first upper accommodating groove and the second upper accommodating groove, and two ends of the upper fixed cavity are communicated with the first upper accommodating groove and the second upper accommodating groove respectively; the lower fixed die cavity and the upper fixed die cavity form the fixed die cavity in a die closing state.

7. The steel pipe bulging apparatus according to claim 5, wherein: the lower movable insert comprises a lower sliding block arranged in the corresponding lower accommodating groove and a lower compression part arranged between the lower sliding block and the lower fixed cavity, and the lower sliding block can slide towards the fixed cavity and compress the lower compression part; the upper movable insert comprises an upper sliding block arranged in the corresponding upper accommodating groove and an upper compression part arranged between the upper sliding block and the upper fixed cavity, and the upper sliding block can slide towards the fixed cavity and compress the upper compression part; the lower and upper slides form the slide assembly in a clamped state, and the lower and upper compression portions form the compression assembly in a clamped state.

8. The steel pipe bulging apparatus according to claim 6, wherein: the lower compression part comprises a plurality of lower moving plates positioned between the lower sliding block and the lower fixed cavity and a first self-recovery element positioned between every two adjacent lower moving plates, and a lower compression gap is formed between every two adjacent lower moving plates; the upper compression part comprises a plurality of upper moving plates positioned between the upper sliding block and the upper fixed cavity and a second self-recovery element positioned between every two adjacent upper moving plates, and an upper compression gap is formed between every two adjacent upper moving plates; the upper and lower moving plates form the moving plate in a clamped state, and the first and second self-restoring elements form the self-restoring member in a clamped state.

9. The steel pipe bulging apparatus according to claim 7, wherein: the first self-recovery element is a first return spring, one end of the first return spring abuts against the lower sliding block, the other end of the first return spring sequentially penetrates through the lower movable plates and then abuts against the inner side groove wall of the lower accommodating groove, and the lower sliding block is connected with the lower movable plate adjacent to the lower sliding block; the second self-recovery element is a second return spring, one end of the second return spring abuts against the upper sliding block, the other end of the second return spring sequentially penetrates through the upper moving plates and then abuts against the inner side groove wall of the upper accommodating groove, and the upper sliding block is connected with the upper moving plate adjacent to the upper sliding block.

10. The steel pipe bulging apparatus according to claim 7, wherein: the lower moving plate comprises a lower laminated plate, a first nesting groove formed in the inner side of the lower laminated plate and a first nesting block formed in the outer side of the lower laminated plate, and the size of a notch of the first nesting groove is smaller than the size in the groove; the first nesting block is provided with a first nesting head which is embedded into the first nesting groove and a first connecting part which is connected between the first nesting head and the lower stacked plate and movably penetrates through the groove opening of the first nesting groove, the thickness of the first nesting head is smaller than the depth of the first nesting groove, and the thickness of the first connecting part is larger than the depth of the groove opening of the first nesting groove;

the upper moving plate comprises an upper laminated plate, a second nesting groove formed in the inner side of the upper laminated plate and a second nesting block formed in the outer side of the upper laminated plate, and the size of a notch of the second nesting groove is smaller than the size in the groove; the second nested block is provided with a second embedded head embedded into the second nested groove and a second connecting part connected between the second embedded head and the upper laminated plate and movably arranged at the groove opening of the second nested groove in a penetrating manner, the thickness of the second embedded head is smaller than the depth of the second nested groove, and the thickness of the second connecting part is larger than the depth of the groove opening of the second nested groove.

11. A steel pipe bulging apparatus according to claim 9, wherein: the lower laminated plate comprises a first lower side plate and a second lower side plate which are positioned on the same plane and are spaced from each other, the outer side surfaces of the first lower side plate and the second lower side plate respectively extend outwards to form a lower extension plate, the outer ends of the two lower extension plates are connected with a lower connecting plate, two ends of the lower connecting plate respectively protrude out of the outer vertical surfaces of the two lower extension plates to form two lower convex parts, and the two lower extension plates and the lower connecting plate are enclosed to form the first nesting groove; the space between the first lower side plate and the second lower side plate forms a notch of the first nesting groove, the inner vertical surfaces of the two lower extension plates form two side groove walls of the first nesting groove, the outer vertical surfaces of the two lower extension plates form the first connecting part, the inner side surface of the lower connecting plate forms a groove bottom wall of the first nesting groove, and the outer side surface of the lower connecting plate and the two lower bulges form a first nesting head of the first nesting block;

the upper laminated plate comprises a first upper side plate and a second upper side plate which are positioned on the same plane and are spaced from each other, the outer side surfaces of the first upper side plate and the second upper side plate respectively extend outwards to form an upper extending plate, the outer ends of the two upper extending plates are connected with an upper connecting plate, two ends of the upper connecting plate respectively protrude out of the outer vertical surfaces of the two upper extending plates to form two upper convex parts, and the two upper extending plates and the upper connecting plate are enclosed to form the second nesting groove; the space between the first upper side plate and the second upper side plate forms a notch of the second nesting groove, inner vertical faces of the two upper extension plates form two side groove walls of the second nesting groove, outer vertical faces of the two upper extension plates form the second connecting portion, the inner side face of the upper connecting plate forms a groove bottom wall of the second nesting groove, and the outer side face and the two upper protrusions of the upper connecting plate form a second nesting head of the second nesting block.

12. A steel pipe bulging method for bulging a steel pipe using a steel pipe bulging apparatus according to any one of claims 1 to 11, comprising the steps of:

s1, closing the upper die and the lower die, enabling the middle part of the steel pipe to be expanded to be located in the fixed die cavity, and enabling two ends of the steel pipe to be expanded to be located in the two expansion die cavities respectively;

s2, driving the two movable push blocks to move towards the fixed die cavity respectively by the driving devices of the first blocking mechanism and the second blocking mechanism, and respectively pushing the sealing punches of the first blocking mechanism and the second blocking mechanism into the two ends of the steel pipe to seal the two ends of the steel pipe;

s3, injecting high-pressure liquid into the steel pipe through an injection channel of the first blocking mechanism and/or the second blocking mechanism, simultaneously, continuously driving the two movable push blocks to compress the two movable injection block assemblies inwards by the two driving devices respectively, and compressing two ends of the steel pipe and supplementing materials to the bulging part of the steel pipe by the two sealing punches respectively;

and S4, the two driving devices respectively drive the two movable push blocks to reset so that the two sealing punches respectively reset along with the two movable push blocks, the two movable insert assemblies reset, and the upper die and the lower die are separated so as to take out the expanded steel pipe.

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