Automatic correction of the concentricity of a blank tube by a hot expander

Abstract

The application discloses a kind of blank tube concentricity automatic correction hot expander, belong to the technical field of hot expander.It includes conveying unit for conveying blank tube, track, intermediate frequency furnace and offline unit, one end of the conveying unit is located on track, the intermediate frequency furnace is between track and offline unit;Pipe feeding unit, the pipe feeding unit is installed on track to continue to advance blank tube transported by conveying unit;Butt joint unit, the butt joint unit is fixedly connected with the end of track close to intermediate frequency furnace;Longitudinal correction unit, the longitudinal correction unit is fixedly connected above butt joint unit;Transverse correction unit, the transverse correction unit is fixedly connected with the end of track and located between butt joint unit and intermediate frequency furnace;A kind of blank tube concentricity automatic correction hot expander of the application avoids the situation that two blank tubes are prone to axial misplacement, radial deviation or extrusion deformation at joint when tail end of a blank tube and head end of next blank tube are butted during conveying.

Description

Technical Field

[0001] This invention relates to the field of thermal expansion machine technology, specifically to a thermal expansion machine for automatic correction of billet concentricity. Background Technology

[0002] In the hot expansion process of seamless steel pipes, the billet pipe usually needs to be continuously heated in a medium-frequency induction heating furnace before entering the expansion station, where the diameter is increased and the wall thickness is adjusted under the action of a mandrel. This process has extremely high requirements for the concentricity of the billet pipe, because any slight eccentricity may be amplified in the high-temperature plastic state, resulting in defects such as uneven wall thickness, excessive ellipticity, or even local cracking in the finished pipe, which seriously affects the product quality and subsequent performance.

[0003] Currently, multiple billet tubes are fed sequentially into an induction furnace for hot expansion using a continuous feeding method. However, in actual production, when the tail end of one billet tube is joined to the head end of the next billet tube during transport, axial misalignment or radial offset can easily occur at the joint due to factors such as manufacturing tolerances, cumulative errors in the conveying mechanism, or unevenness of the billet tube end faces. Although this joint deviation may not be obvious at room temperature, it will cause significant eccentric expansion when the billet tube expands under the guidance of the mandrel in a high-temperature softened state if its geometric center fails to coincide with the mandrel axis.

[0004] Most existing hot expansion equipment lacks the ability to monitor and dynamically correct the concentricity of billet tubes, especially during continuous billet tube feeding, where it cannot effectively identify and compensate for instantaneous eccentricity at the joints. While some equipment is equipped with mechanical centering devices, their slow response speed and low adjustment accuracy make them unsuitable for high-speed continuous production and cannot adaptively adjust for specific deviations at the joints of each billet tube. Therefore, how to automatically detect and correct concentricity issues caused by joint deviations during the continuous hot expansion process of billet tubes in the induction furnace, ensuring that the billet tube remains coaxial with the expanding mandrel, has become a key technical bottleneck for improving the quality and production efficiency of hot-expanded tubes. Therefore, it is necessary to provide a hot expansion machine with automatic billet tube concentricity correction to solve these problems. Summary of the Invention

[0005] In view of the above-mentioned problems in the prior art, the purpose of the present invention is to provide a hot expander with automatic correction of billet concentricity to solve the problems mentioned in the background art.

[0006] The technical solution adopted by the present invention to solve its technical problem is: an automatic concentricity correction hot expansion machine for billet tubes, comprising a conveying unit for conveying billet tubes, a track, an intermediate frequency furnace and an unloading unit, wherein one end of the conveying unit is located on the track, and the intermediate frequency furnace is located between the track and the unloading unit;

[0007] A pipe feeding unit, which is mounted on a track to receive the billet pipe transported by the conveying unit and continue forward;

[0008] A docking unit, wherein the docking unit is fixedly connected to one end of the track near the intermediate frequency furnace;

[0009] A longitudinal correction unit is fixedly connected above the docking unit;

[0010] A lateral correction unit is fixedly connected to the end of the track and located between the docking unit and the intermediate frequency furnace;

[0011] The mandrel has one end located inside the tube feeding unit and the other end located inside the intermediate frequency furnace. The docking unit, longitudinal correction unit and transverse correction unit are distributed along the circumferential direction of the mandrel.

[0012] When several billet tubes continuously enter the intermediate frequency furnace along the mandrel for tube expansion, the tail end of the previous billet tube and the head end of the next billet tube are both located on the docking unit, and the joint of the two billet tubes is subjected to pressure by the longitudinal correction unit. The docking unit moves the two billet tubes under pressure towards the intermediate frequency furnace at a speed consistent with that of the tube feeding unit.

[0013] Furthermore, the lateral correction unit has a mounting bracket that is fixedly connected to the end of the track near the intermediate frequency furnace;

[0014] The docking unit includes a sliding platform mounted on a mounting frame. A guide rail is fixedly connected to the sliding platform along the axis of the billet tube, and a V-shaped support block is slidably connected to the guide rail.

[0015] The longitudinal correction unit has a support column fixedly connected to the top of both sides of the support block. A mounting base is fixedly connected to the support column, and a longitudinal hydraulic cylinder is fixedly connected to the mounting base. The output end of the longitudinal hydraulic cylinder has a longitudinal pressing block that faces the support block and slides up and down.

[0016] The tail end of the previous billet tube and the head end of the next billet tube are held by the support block and the longitudinal pressure block.

[0017] Furthermore, the docking unit also includes a positioning seat and a base that are fixedly connected to the track. A slider is slidably connected to the base, and a pipe-feeding cylinder is hinged to the positioning seat. The output end of the pipe-feeding cylinder is hinged to the slider so that the slider slides on the base.

[0018] Furthermore, a top cylinder is fixedly connected to the base, and the output end of the top cylinder is fixedly connected to the bottom of the support block to drive the support block and the longitudinal correction unit to rise and fall.

[0019] The top cylinder extends outward in the circumferential direction with a supporting block, and the sliding platform is located between the supporting block and the supporting block;

[0020] The sliding platform is a liftable platform with a through groove located between two guide rails, and the output end of the top cylinder is located inside the through groove.

[0021] Furthermore, the lateral correction unit includes a symmetrically arranged mounting frame, a lateral hydraulic cylinder, and a lateral pressure block. The lateral hydraulic cylinder is fixedly connected to the mounting frame, the lateral pressure block is fixedly installed at the output end of the lateral hydraulic cylinder, and the sliding platform is located between the two lateral pressure blocks.

[0022] Furthermore, the pipe feeding unit includes a pusher cylinder, a gantry, and a pipe feeding trolley. The gantry is fixedly installed on one end of the track near the conveying unit. The pusher cylinder is fixedly installed on the gantry and its output end is fixedly connected to the pipe feeding trolley. The pipe feeding trolley slides on the track via pulleys.

[0023] The pipe delivery vehicle has a front frame at the front and a rear frame at the rear, and several connecting columns are fixedly connected between the front frame and the rear frame.

[0024] Each of the connecting columns is fixedly connected to a vertical lifting cylinder, and the output end of the lifting cylinder is retractably connected to a first V-shaped roller.

[0025] Furthermore, the speed of the push cylinder is consistent with the speed of the pipe delivery cylinder.

[0026] Furthermore, a main limiting plate is slidably connected up and down on the side of the gantry away from the pipe delivery vehicle, and a hanging lug is fixedly connected to the top of the main limiting plate. The main limiting plate has a main limiting port with an opening facing downward.

[0027] The spindle has a shaft section, on which a notch is provided that matches the main limiting port;

[0028] The mandrel also includes an expanded tube section, a transition section, and a connector located inside the intermediate frequency furnace. The transition section is located between the expanded tube section and the connector. The diameter of the expanded tube section is larger than the diameter of the connector. The diameter of the transition section gradually increases from one end of the connector to the expanded tube section.

[0029] The shaft section passes through a conveying unit, a track, a pipe feeding unit, a docking unit, a longitudinal correction unit, and a lateral correction unit.

[0030] Furthermore, the front frame has two sliding front limiting plates in the middle, which together form a front through hole with a diameter consistent with the diameter of the shaft section.

[0031] The rear frame has two sliding rear limiting plates in the middle, which together form a rear through hole with a diameter consistent with that of the shaft section.

[0032] Furthermore, the end of the mandrel also has a vertically arranged guide wheel, the diameter of which is the same as the inner diameter of the blank tube, and the outer diameter of the shaft section is smaller than the inner diameter of the blank tube.

[0033] The beneficial effects of the present invention are as follows: The present invention provides an automatic concentricity correction hot expansion machine for billet tubes, which clamps the joint of two billet tubes by setting a support block and a longitudinal pressure block, and feeds the joint of the two billet tubes towards the direction of the medium frequency furnace by setting a feeding cylinder to assist the pushing cylinder to feed the tubes. This can improve the stability of the joint of the billet tubes, prevent deviation, and avoid the situation where the tail end of one billet tube and the head end of the next billet tube are connected during the conveying process, and the two billet tubes are easily subjected to excessive force at the joint, which can easily cause axial misalignment, radial deviation or extrusion deformation.

[0034] By setting up a lateral correction unit, the initial position of the first billet tube can be determined, and in subsequent tube feeding, the lateral correction unit can play an auxiliary positioning role, increasing the positioning accuracy between billets.

[0035] By setting a front limit plate and a rear limit plate on the pipe delivery vehicle, the billet pipe can be transported. At the same time, when the limit plates come together, they can cover the mandrel and better position the mandrel, preventing the mandrel from shifting position.

[0036] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0037] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0038] Figure 1 This is an overall schematic diagram of the present invention;

[0039] Figure 2 This is a schematic diagram of the docking unit of the present invention;

[0040] Figure 3 For the present invention Figure 2 Enlarged diagram of area A in the middle;

[0041] Figure 4 This is a schematic diagram of the overall docking unit of the present invention;

[0042] Figure 5 This is a schematic diagram of the longitudinal correction unit of the present invention;

[0043] Figure 6 This is a side view of the overall docking unit of the present invention;

[0044] Figure 7 This is a schematic diagram of the tube feeding unit of the present invention;

[0045] Figure 8 This is a schematic diagram of the other side of the tube feeding unit of the present invention;

[0046] Figure 9 This is a schematic diagram of the mandrel of the present invention;

[0047] Figure 10 This is a schematic diagram of the mandrel position according to the present invention;

[0048] Figure 11 This is a schematic diagram of the support unit of the present invention;

[0049] Figure 12 This is a schematic diagram of the billet tube connection according to the present invention;

[0050] Figure 13 For the present invention Figure 12 Enlarged diagram of area B in the middle;

[0051] Figure 14 For the present invention Figure 12 Enlarged diagram of area C;

[0052] The following are the labeling elements in the figure:

[0053] 1. Conveying unit;

[0054] 2. Track;

[0055] 3. Medium frequency furnace;

[0056] 4. Offline unit;

[0057] 5. Pipe delivery unit; 51. Push cylinder; 52. Gantry; 521. Main limit plate; 5211. Main limit port; 522. Hanging lug; 53. Pipe delivery trolley; 531. Front frame; 5311. Front limit plate; 532. Rear frame; 5321. Rear limit plate; 533. Connecting column; 54. Lifting cylinder; 55. First V-shaped roller;

[0058] 6. Docking unit; 61. Positioning seat; 62. Pipe delivery cylinder; 63. Base; 64. Slider; 65. Top cylinder; 651. Support block; 66. Guide column; 67. Placement seat; 68. Sliding platform; 681. Through groove; 682. Guide rail; 69. Support block;

[0059] 7. Longitudinal straightening unit; 71. Support column; 72. Mounting base; 73. Longitudinal hydraulic cylinder; 74. Longitudinal pressure block;

[0060] 8. Lateral correction unit; 81. Mounting bracket; 82. Lateral hydraulic cylinder; 83. Lateral pressure block;

[0061] 9. Mandrel; 91. Expanded tube section; 92. Transition section; 93. Connector; 94. Shaft body section; 95. Notch section; 96. Guide wheel;

[0062] 10. Support unit; 101. Connecting frame; 102. Positioning cylinder; 103. Second V-shaped roller;

[0063] 11. Blank tube. Detailed Implementation

[0064] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0065] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0066] like Figure 1-14 As shown, the present invention provides a technical solution: an automatic concentricity correction hot expansion machine for billet tubes, including a conveying unit 1, a track 2, an intermediate frequency furnace 3, and an unloading unit 4 for conveying billet tubes 11. One end of the conveying unit 1 is located on the track 2, and the intermediate frequency furnace 3 is located between the track 2 and the unloading unit 4.

[0067] Pipe feeding unit 5 is installed on track 2 to receive the billet pipe 11 transported by conveying unit 1 and continue to move forward;

[0068] The docking unit 6 is fixedly connected to one end of the track 2 near the intermediate frequency furnace 3;

[0069] Longitudinal correction unit 7 is fixedly connected above docking unit 6;

[0070] The transverse correction unit 8 is fixedly connected to the end of the track 2 and is located between the docking unit 6 and the medium frequency furnace 3.

[0071] Mandrel 9, one end of mandrel 9 is located in pipe feeding unit 5, and the other end is located in medium frequency furnace 3. Docking unit 6, longitudinal correction unit 7 and transverse correction unit 8 are distributed along the circumferential direction of mandrel 9.

[0072] When several billet tubes 11 continuously enter the intermediate frequency furnace 3 along the mandrel 9 for tube expansion, the tail end of the previous billet tube 11 and the head end of the next billet tube 11 are both located on the docking unit 6, and the joint of the two billet tubes 11 is subjected to pressure by the longitudinal correction unit 7. The docking unit 6 moves the two billet tubes 11 under pressure towards the intermediate frequency furnace 3 at a speed consistent with that of the tube feeding unit 5.

[0073] The transverse correction unit 8 has a mounting bracket 81 that is fixedly connected to one end of the track 2 near the intermediate frequency furnace 3;

[0074] The docking unit 6 includes a sliding platform 68 mounted on the mounting frame 81. A guide rail 682 is fixedly connected to the sliding platform 68 along the axis of the blank tube 11. A V-shaped support block 69 is slidably connected to the guide rail 682.

[0075] The longitudinal correction unit 7 has a support column 71 fixedly connected to the top of both sides of the support block 69. A mounting base 72 is fixedly connected to the support column 71. A longitudinal cylinder 73 is fixedly connected to the mounting base 72. The output end of the longitudinal cylinder 73 has a longitudinal pressure block 74 that is directly opposite to the support block 69 and slides up and down.

[0076] The tail end of the previous billet tube 11 and the head end of the next billet tube 11 are held by the support block 69 and the longitudinal pressure block 74.

[0077] The docking unit 6 also includes a positioning seat 61 and a base 63 that are fixedly connected to the track 2. A slider 64 is slidably connected to the base 63, and a pipe feeding cylinder 62 is hinged to the positioning seat 61. The output end of the pipe feeding cylinder 62 is hinged to the slider 64 so that the slider 64 slides on the base 63.

[0078] A top cylinder 65 is fixedly connected to the base 63. The output end of the top cylinder 65 is fixedly connected to the bottom of the support block 69 to drive the support block 69 and the longitudinal correction unit 7 to rise and fall.

[0079] The top cylinder 65 extends outward in the circumferential direction with a supporting block 651, and the sliding platform 68 is located between the supporting block 651 and the supporting block 69;

[0080] The sliding platform 68 is a liftable platform and has a through groove 681. The through groove 681 is located between two guide rails 682, and the output end of the top cylinder 65 is located in the through groove 681.

[0081] The lateral correction unit 8 includes a symmetrically arranged mounting frame 81, a lateral cylinder 82, and a lateral pressure block 83. The lateral cylinder 82 is fixedly connected to the mounting frame 81, and the lateral pressure block 83 is fixedly installed at the output end of the lateral cylinder 82. The sliding platform 68 is located between the two lateral pressure blocks 83.

[0082] The pipe feeding unit 5 includes a pusher cylinder 51, a gantry 52, and a pipe feeding carriage 53. The gantry 52 is fixedly installed on one end of the track 2 near the conveying unit 1. The pusher cylinder 51 is fixedly installed on the gantry 52 and its output end is fixedly connected to the pipe feeding carriage 53. The pipe feeding carriage 53 slides on the track 2 through pulleys.

[0083] The pipe delivery vehicle 53 has a front frame 531 at the front and a rear frame 532 at the rear, and several connecting columns 533 are fixedly connected between the front frame 531 and the rear frame 532.

[0084] Vertical lifting cylinders 54 are fixedly connected to the inner side of the connecting column 533, and the output end of the lifting cylinder 54 is retractably connected to a first V-shaped roller 55.

[0085] The speed of push cylinder 51 is the same as the speed of pipe delivery cylinder 62.

[0086] A main limiting plate 521 is slidably connected up and down on the side of the gantry 52 away from the pipe delivery vehicle 53. A hanging ear 522 is fixedly connected to the top of the main limiting plate 521. The main limiting plate 521 has a main limiting port 5211 with the opening facing downward.

[0087] The spindle 9 has a shaft section 94, on which a notch 95 is provided to match the main limiting port 5211;

[0088] The mandrel 9 also includes an expansion tube section 91, a transition section 92 and a connector 93 located in the medium frequency furnace 3. The transition section 92 is located between the expansion tube section 91 and the connector 93. The diameter of the expansion tube section 91 is larger than the diameter of the connector 93. The diameter of the transition section 92 gradually increases from one end of the connector 93 to the expansion tube section 91.

[0089] The shaft section 94 passes through the conveying unit 1, track 2, pipe feeding unit 5, docking unit 6, longitudinal correction unit 7, and lateral correction unit 8.

[0090] The front frame 531 has two sliding front limit plates 5311 in the middle. When the front limit plates 5311 are brought together, they form a front through hole with a diameter that is the same as the diameter of the shaft section 94.

[0091] The rear frame 532 has two rear limiting plates 5321 that slide up and down in the middle. When the rear limiting plates 5321 are brought together, they form a rear through hole with a diameter that is the same as the diameter of the shaft section 94.

[0092] The end of the mandrel 9 also has a vertically arranged guide wheel 96. The diameter of the guide wheel 96 is the same as the inner diameter of the blank tube 11, and the outer diameter of the shaft section 94 is smaller than the inner diameter of the blank tube 11.

[0093] In one embodiment, the working principle of the thermal expander

[0094] Specifically, support units 10 are provided at multiple locations of the thermal expansion machine to support the mandrel 9, especially at the side of the gantry 52 and the side of the pipe delivery trolley 53. The support units 10 are connected to the corresponding components through the connecting frame 101. The connecting frame 101 also has a positioning cylinder 102 that can extend and retract vertically. The output end of the positioning cylinder 102 is fixedly connected to a second V-shaped roller 103 that holds the mandrel 9.

[0095] When the mandrel 9 is placed into the heat expansion machine, the transverse pressure block 83 is activated to clamp the shaft body section 94. At the same time, the position of the mandrel 9 is determined by the support of the second V-shaped roller 103.

[0096] An auxiliary tube is attached to the tail of the billet tube 11, and the billet tube 11 is placed into the conveying unit 1. The conveying unit 1 is driven by a motor to drive the chain, so that the V-shaped roller carrying the billet tube 11 rolls and conveys the billet tube 11 into the hot expansion machine.

[0097] During the conveying process, the inner wall of the billet tube 11 first contacts the guide wheel 96. At this time, the upper and lower parts of the guide wheel 96 contact the billet tube 11. Then, the positioning cylinder 102 of the support unit 10 is lowered, so that the second V-shaped roller 103 descends without hindering the entry of the billet tube 11.

[0098] The front limit plates 5311 are brought closer together, and the billet tube 11 continues to move forward along the first V-shaped roller 55 until the main body enters the tube delivery carriage 53. The first end of the billet tube 11 touches the end face of the front limit plate 5311. At this time, the conveying unit 1 is moved backward, and the auxiliary tube section of the billet tube 11 is moved outward from the conveying unit 1. The tail end notch 95 of the mandrel 9 is exposed. The main limit plate 521 is lowered by the lifting device connected by the lug 522. At this time, the main limit port 5211 falls into the notch 95, which restricts the movement of the mandrel 9 in the axial direction.

[0099] At this time, the billet tube 11 is completely inside the tube delivery car 53. The rear limit plates 5321 are brought together and closed. At this time, the tail end of the billet tube 11 also contacts the rear limit plate 5321, pushing the push cylinder 51. The gantry 52 moves towards the direction of the medium frequency furnace 3. After reaching the maximum stroke of the push cylinder 51, the lower frame lifting cylinder 54 is lowered, the first V-shaped roller 55 descends, and at the same time the front limit plate 5311 and the rear limit plate 5321 are opened, so that the billet tube 11 falls onto the mandrel 9.

[0100] After retracting the pusher cylinder 51 to its minimum stroke, the second billet tube 11 is fed into the tube delivery carriage 53 again in the manner described above. At this time, the pusher cylinder 51 is extended, and the front end face of the front limit plate 5311 will press against the tail end of the previous billet tube 11 and move forward, while the rear end face contacts the head end of the second billet tube 11. At this time, the transverse pressure block 83 is released to allow the second billet tube 11 to pass through. When the second billet tube 11 reaches the medium-frequency furnace 3, the pusher cylinder 51 is stopped, and the sliding platform 68 is raised at the same time. The top cylinder 65 drives the sliding platform 68 to rise or fall, causing the guide column 66 to extend and retract within the placement seat 67, so that the support block 69 supports the bottom of the billet tube 11. At the same time, the transverse pressure block 83 is brought closer to press against the billet tube 11 to secure the billet. At the center of tube 11, the transverse pressure block 83 retracts, and the longitudinal cylinder 73 is activated to descend. The longitudinal pressure block 74 descends to clamp the tube body of the billet tube 11 with the support block 69. Then the push cylinder 51 is activated, and the tube feeding cylinder 62 is activated to move synchronously with the push cylinder 51, so that the support block 69 slides on the guide rail 682 and the top cylinder 65 slides in the through groove 681, sending the billet tube 11 into the medium frequency furnace 3. At this time, the billet tube 11 advances along the transition section 92 to the tube expansion section 91 to carry out tube expansion operation. After the tube feeding cylinder 62 reaches its maximum stroke, the support block 69 is lowered, the longitudinal pressure block 74 is raised, the tube feeding cylinder 62 is retracted, and the lowering support block 69 and the rising longitudinal pressure block 74 are controlled to move closer to clamp the billet tube 11, thus reciprocating to transport the billet tube 11.

[0101] After the pipe delivery vehicle 53 reaches its maximum stroke, the second billet pipe 11 also reaches its designated position. After the pipe delivery unit 5 retracts to install the third billet pipe 11, as the pipe delivery vehicle 53 moves forward, the end face of the front limit plate 5311 abuts against the tail end of the second billet pipe 11 and moves closer to the first billet pipe 11. After the head end of the second billet pipe 11 contacts the tail end of the first billet pipe 11, the top cylinder 65 is raised upward to position the joint of the two billet pipes 11 on the support block 69. Then, the longitudinal cylinder 73 lowers the longitudinal pressure block 74, so that the longitudinal pressure block 74 and the support block 69 fix the joint of the two billet pipes 11. The tubes are squeezed together to prevent misalignment at the joint. Then, the sliding block 64 is pushed towards the medium-frequency furnace 3 by the tube feeding cylinder 62, so that the joint of the longitudinal pressure block 74 and the support block 69 clamping the billet tube 11 moves forward a certain distance to maintain the concentricity of the two billets. After the tube feeding cylinder 62 reaches its maximum stroke, it releases the clamping of the joint of the two billet tubes 11 and the tube feeding cylinder 62 retracts to clamp the tube body of the second billet tube 11. In subsequent operations, when the billet tube 11 needs to be replaced, the above operation can be followed to complete the process. After the tube expansion is completed, the billet tube 11 falls into the unloading unit 4 and is transported to the designated position.

[0102] Throughout the operation, the transverse pressure block 83 plays an auxiliary role, while the support block 69 bears the main pressure under the influence of gravity.

[0103] In summary, the thermal expansion machine uses a support block 69 and a longitudinal pressure block 74 to clamp the joint of two billet tubes 11. It also uses a pipe feeding cylinder 62 to feed the joint of the two clamped billet tubes 11 towards the direction of the medium frequency furnace 3, which assists the push cylinder 51 in feeding the pipe. This improves the stability of the joint of the billet tubes 11, prevents deviation, and avoids the situation where the tail end of one billet tube 11 and the head end of the next billet tube 11 are connected during the conveying process. This avoids the situation where the two billet tubes 11 are subjected to excessive force at the joint, which can easily cause axial misalignment, radial displacement, or extrusion deformation.

[0104] By setting the lateral correction unit 8, the initial position of the first billet tube 11 can be located, and in the subsequent tube feeding, the lateral correction unit 8 can play an auxiliary positioning role, increasing the positioning accuracy between billet tubes 11.

[0105] By setting a front limiting plate 5311 and a rear limiting plate 5321 on the pipe delivery vehicle 53, the blank pipe 11 can be transported. At the same time, when the limiting plates come together, they can cover the mandrel 9 and better position the mandrel 9, preventing the position of the mandrel 9 from shifting.

[0106] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An automatic concentricity correction hot expander for billet tubes, characterized in that: It includes a conveying unit (1) for conveying billet tube (11), a track (2), an intermediate frequency furnace (3) and a lowering unit (4), one end of the conveying unit (1) is located on the track (2), and the intermediate frequency furnace (3) is located between the track (2) and the lowering unit (4); The pipe delivery unit (5) is installed on the track (2) to receive the billet pipe (11) transported by the delivery unit (1) and continue to move forward; The docking unit (6) is fixedly connected to one end of the track (2) near the intermediate frequency furnace (3); A longitudinal correction unit (7) is fixedly connected above the docking unit (6); A transverse correction unit (8) is fixedly connected to the end of the track (2) and located between the docking unit (6) and the intermediate frequency furnace (3); The mandrel (9) has one end located in the tube feeding unit (5) and the other end located in the medium frequency furnace (3). The docking unit (6), the longitudinal correction unit (7) and the transverse correction unit (8) are distributed along the circumferential direction of the mandrel (9). When several billet tubes (11) continuously enter the intermediate frequency furnace (3) along the mandrel (9) for tube expansion, the tail end of the previous billet tube (11) and the head end of the next billet tube (11) are both located on the docking unit (6) and the joint of the two billet tubes (11) is subjected to pressure by the longitudinal correction unit (7). The docking unit (6) moves the two billet tubes (11) subjected to pressure toward the intermediate frequency furnace (3) at a speed consistent with that of the tube feeding unit (5). The lateral correction unit (8) has a mounting bracket (81) that is fixedly connected to one end of the track (2) near the intermediate frequency furnace (3). The docking unit (6) includes a sliding platform (68) mounted on a mounting frame (81). A guide rail (682) is fixedly connected to the sliding platform (68) along the axis of the blank tube (11). A V-shaped support block (69) is slidably connected to the guide rail (682). The longitudinal correction unit (7) has a support column (71) fixedly connected to the top of both sides of the support block (69). A mounting seat (72) is fixedly connected to the support column (71). A longitudinal cylinder (73) is fixedly connected to the mounting seat (72). The output end of the longitudinal cylinder (73) has a longitudinal pressure block (74) that is directly opposite to the support block (69) and slides up and down. The tail end of the previous billet tube (11) and the head end of the next billet tube (11) are held by the support block (69) and the longitudinal pressure block (74).

2. The automatic concentricity correction hot expander for billet tubes according to claim 1, characterized in that: The docking unit (6) also includes a positioning seat (61) and a base (63) fixedly connected to the track (2). A slider (64) is slidably connected to the base (63). A pipe-feeding cylinder (62) is hinged to the positioning seat (61). The output end of the pipe-feeding cylinder (62) is hinged to the slider (64) so ​​that the slider (64) slides on the base (63).

3. The automatic concentricity correction hot expander for billet tubes according to claim 2, characterized in that: A top cylinder (65) is fixedly connected to the base (63), and the output end of the top cylinder (65) is fixedly connected to the bottom of the support block (69) to drive the support block (69) and the longitudinal correction unit (7) to rise and fall. The top cylinder (65) extends outward in the circumferential direction with a retaining block (651), and the sliding platform (68) is located between the retaining block (651) and the supporting block (69); The sliding platform (68) is a liftable platform and has a through groove (681). The through groove (681) is located between two guide rails (682), and the output end of the top cylinder (65) is located in the through groove (681).

4. The automatic concentricity correction hot expander for billet tubes according to claim 3, characterized in that: The lateral correction unit (8) includes a symmetrically arranged mounting bracket (81), a lateral cylinder (82), and a lateral pressure block (83). The lateral cylinder (82) is fixedly connected to the mounting bracket (81), and the lateral pressure block (83) is fixedly installed at the output end of the lateral cylinder (82). The sliding platform (68) is located between the two lateral pressure blocks (83).

5. The automatic concentricity correction hot expander for billet tubes according to claim 2, characterized in that: The pipe delivery unit (5) includes a push cylinder (51), a gantry (52), and a pipe delivery cart (53). The gantry (52) is fixedly installed on one end of the track (2) near the conveying unit (1). The push cylinder (51) is fixedly installed on the gantry (52) and its output end is fixedly connected to the pipe delivery cart (53). The pipe delivery cart (53) slides on the track (2) through pulleys. The pipe delivery vehicle (53) has a front frame (531) at the front and a rear frame (532) at the rear, and a number of connecting columns (533) are fixedly connected between the front frame (531) and the rear frame (532). The inner side of each connecting column (533) is fixedly connected to a vertical lifting cylinder (54), and the output end of the lifting cylinder (54) is retractably connected to a first V-shaped roller (55).

6. The automatic concentricity correction hot expander for billet tubes according to claim 5, characterized in that: The speed of the push cylinder (51) is the same as the speed of the pipe delivery cylinder (62).

7. The automatic concentricity correction hot expander for billet tubes according to claim 5, characterized in that: The gantry (52) is slidably connected to a main limiting plate (521) on the side away from the pipe delivery vehicle (53). The top of the main limiting plate (521) is fixedly connected to a hanging ear (522). The main limiting plate (521) has a main limiting port (5211) with an opening facing downward. The spindle (9) has a shaft section (94), and a notch (95) that matches the main limiting port (5211) is provided on the shaft section (94). The shaft section (94) passes through the conveying unit (1), the track (2), the pipe feeding unit (5), the docking unit (6), the longitudinal correction unit (7), and the lateral correction unit (8). The mandrel (9) also includes an expansion tube section (91), a transition section (92) and a connector (93) located in the medium frequency furnace (3). The transition section (92) is located between the expansion tube section (91) and the connector (93). The diameter of the expansion tube section (91) is larger than the diameter of the connector (93). The diameter of the transition section (92) gradually increases from one end of the connector (93) to the expansion tube section (91).

8. The automatic concentricity correction hot expander for billet tubes according to claim 7, characterized in that: The front frame (531) has two sliding front limit plates (5311) in the middle. When the front limit plates (5311) are brought together, they form a front through hole with a diameter that is the same as the diameter of the shaft section (94). The rear frame (532) has two sliding rear limit plates (5321) in the middle. When the rear limit plates (5321) are brought together, they form a rear through hole with a diameter that is the same as that of the shaft section (94).

9. The automatic concentricity correction hot expander for billet tubes according to claim 7, characterized in that: The end of the mandrel (9) also has a vertically arranged guide wheel (96), the diameter of which is the same as the inner diameter of the blank tube (11), and the outer diameter of the shaft section (94) is smaller than the inner diameter of the blank tube (11).

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