A steel pipe expanding apparatus

Abstract

This utility model relates to the field of steel pipe processing and discloses a steel pipe expansion device. It includes a support platform, a mounting circular seat, an expansion die cone, and an elastic force adjustment assembly. The mounting circular seat is fixedly connected to the support platform. The expansion die cone is a rotating body and includes multiple arc-shaped expansion units. These expansion units are slidably connected to the mounting circular seat along their respective radial directions. The mounting circular seat is equipped with elastic components that are the same number as and correspond one-to-one with the expansion units. These elastic components are adapted to drive the corresponding expansion units towards the axis of the mounting circular seat. The elastic force adjustment assembly includes a rotating ring threadedly connected to the mounting circular seat. Driving the rotating ring to rotate relative to the mounting circular seat allows for simultaneous adjustment of the elastic force applied by the multiple elastic components to the corresponding expansion units. This utility model enables the elastic force of the elastic components on the expansion units to be adjusted conveniently; reduces losses and improves the quality of pipe expansion; and reduces equipment downtime for maintenance.

Description

Technical Field

[0001] This utility model relates to the field of steel pipe processing technology, and more specifically, to a steel pipe expansion device. Background Technology

[0002] Water heaters typically have stainless steel flue pipes. Due to layout constraints, some houses have the outdoor end of the flue pipe facing north. In some areas, monsoon winds blow towards the flue pipe, making backflow of flue gas a common problem. Therefore, a stainless steel one-way valve is usually installed at the protruding end of the flue pipe to prevent backflow. The stainless steel one-way valve consists of an expanded steel pipe and a one-way stainless steel valve cover installed inside the expanded steel pipe. The expanded steel pipe initially has the same inner and outer diameters as the stainless steel flue pipe. Then, one end is flared using a pipe-expanding device (for example, expanding a 60mm outer diameter pipe to an 80mm outer diameter), while the other end retains its original outer diameter for easy connection to the flue pipe.

[0003] The existing steel pipe expansion equipment includes a frame, an expansion cone, and a constraint truncated cone. The expansion cone is a cylinder composed of multiple arc-shaped columns connected to the constraint truncated cone, and these columns move radially along the constraint truncated cone. The constraint truncated cone is mounted on the frame with multiple bolts. A cylinder is fixedly connected to the frame, and a conical column is fixedly connected to the cylinder's extension rod. Multiple arc-shaped columns are arranged circumferentially at intervals on the outer side of the conical column and are in contact with it. During expansion, the steel pipe is placed on the expansion cone, and the cylinder drives the conical column upward, causing the multiple arc-shaped columns to move radially outward, thereby expanding the outer diameter of the steel pipe. During this process, to ensure that the multiple arc-shaped columns automatically converge after the conical column descends, a rubber ring is fitted onto each of the arc-shaped columns. However, the rubber ring is prone to affecting the reset of the arc-shaped cylinder due to elastic fatigue. Since the rubber ring is located inside the constraint frustum, adjusting the elasticity of the rubber ring or replacing it with a new rubber ring requires removing the entire constraint frustum, which is quite inconvenient. Utility Model Content

[0004] To address at least one of the aforementioned problems, this utility model provides a steel pipe expansion device, comprising a support platform and an expansion mechanism. The expansion mechanism includes a mounting base, an expansion die cone, and an elastic force adjustment assembly. The mounting base is fixedly connected to the support platform. The expansion die cone is a rotating body and includes multiple arc-shaped expansion units. Each expansion unit is slidably connected to the mounting base along a radial direction corresponding to the mounting base. The mounting base is provided with elastic components in the same number as the expansion units. Multiple sets of elastic components correspond one-to-one with multiple expansion units. The elastic components are adapted to drive the corresponding expansion unit to move closer to the axis of the mounting base. The elastic force adjustment assembly includes a rotating ring threadedly connected to the mounting base. After the rotating ring is driven to rotate relative to the mounting base, it is adapted to simultaneously adjust the elastic force applied by the multiple elastic components to the corresponding expansion unit.

[0005] Optionally, two expansion mechanisms are provided at intervals, and the outer diameters of the expansion die cones in the two expansion mechanisms are different. The steel pipe needs to be processed by the expansion of the two expansion mechanisms in sequence.

[0006] Optionally, the expansion die cone has a tapered hole inside, and the tapered hole penetrates the expansion die cone in a vertical direction.

[0007] Optionally, the outer diameter of the upper side of the expansion die cone is smaller than the outer diameter of the lower side, and an annular spring is sleeved on the upper side of the expansion die cone, the outer diameter of the annular spring being smaller than the inner diameter of the steel pipe.

[0008] Optionally, the mounting base has a circular groove at its bottom, and a insertion hole is formed at the bottom of the groove. The insertion hole penetrates the mounting base, and the diameter of the insertion hole is smaller than the diameter of the circular groove. The expansion tube die cone is inserted into the insertion hole and is clearance-fitted with the insertion hole. Each expansion tube unit has a fan-shaped plate integrally formed at its bottom, and the outer diameter of the fan-shaped plate is larger than the diameter of the insertion hole.

[0009] Optionally, a support base plate is fixedly installed in the circular groove, a positioning guide post is provided on the top of the support base plate, and an elongated hole is opened on the fan-shaped plate. The length direction of the elongated hole is the radial direction of the mounting circular seat, and the positioning guide post is inserted into the elongated hole.

[0010] Optionally, the circular groove has a transverse sliding groove in its wall, and the elastic component includes a drive spring and a sliding block. The sliding block is slidably inserted into the transverse sliding groove, and the two ends of the drive spring abut against the sliding block and the sector plate, respectively.

[0011] Optionally, the elastic adjustment assembly further includes a drive rod. The bottom of the mounting base has a vertical sliding groove communicating with the horizontal sliding groove. The vertical sliding groove is located at the end of the horizontal sliding groove away from the sector plate. The drive rod is slidably inserted into the vertical sliding groove. One end of the sliding block is inserted into the vertical sliding groove and contacts the drive rod. The rotating ring is threaded to the bottom of the mounting base, and the drive rod is located at the top of the rotating ring. When the rotating ring rotates, it will drive the drive rod to rise in the vertical sliding groove, thereby driving the sliding block to move towards the side closer to the sector plate.

[0012] Optionally, the top of the drive rod is provided with a drive ramp, and the side of the sliding block near the drive rod is provided with a mating ramp that fits with the drive ramp.

[0013] Optionally, the bottom of the mounting base is provided with a threaded ring groove, the top of the rotating ring is fixedly provided with a threaded ring, the outer diameter of the threaded ring is smaller than the outer diameter of the rotating ring, the drive rod is located outside the threaded ring, and the threaded ring is threadedly installed in the threaded ring groove.

[0014] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0015] 1. Each expansion tube unit has an individual elastic component to drive the expansion tube unit to reset, making the reset of each expansion tube unit more stable. If the elastic force applied by the elastic component to the expansion tube unit during reset decreases, the rotating ring can be directly rotated for adjustment without removing the entire mounting base, thus improving the convenience of adjustment.

[0016] 2. After the rotating ring rotates, multiple elastic components can be adjusted simultaneously. Compared with adjusting each elastic component individually, it can form a modular adjustment structure, which improves the convenience of adjustment.

[0017] 3. During pipe expansion, the expansion mechanism with a smaller outer diameter first expands the steel pipe, and then another expansion mechanism with a larger outer diameter directly expands the steel pipe to the required outer diameter. This two-stage expansion method can avoid cracking of the steel pipe due to a large expansion size at one time, reduce losses, and improve the quality of pipe expansion.

[0018] 4. The lifespan of the drive spring is longer than that of the rubber ring, and it is less prone to elastic fatigue, thus reducing the downtime for equipment maintenance and increasing the service life of the equipment.

[0019] 5. The smaller outer diameter of the upper side of the expansion die cone improves the smoothness of the steel pipe being fitted onto the expansion die cone. At the same time, the ring spring fitted on the upper side of the expansion die cone helps to improve the smoothness of the single expansion tube resetting. Attached Figure Description

[0020] Figure 1 This is a structural diagram of the steel pipe expansion device in this embodiment of the present invention;

[0021] Figure 2 This is a structural diagram of the mounting base, hydraulic cylinder, and spring adjustment assembly in an embodiment of this utility model;

[0022] Figure 3 This is an exploded view of the mounting base, expansion tube die cone, elastic adjustment component, and elastic component in an embodiment of this utility model.

[0023] Figure 4 This is a structural diagram of the expansion tube die cone in an embodiment of this utility model;

[0024] Figure 5 This is a cross-sectional view of the mounting base, expansion tube cone, elastic adjustment component, and elastic component in an embodiment of this utility model.

[0025] Explanation of reference numerals in the attached drawings: 1. Support platform; 11. Hydraulic cylinder; 2. Mounting round seat; 21. Circular groove; 22. Insertion hole; 23. Support base plate; 24. Horizontal sliding groove; 25. Vertical sliding groove; 26. Threaded ring groove; 3. Expanding tube die cone; 31. Expanding tube unit; 32. Sector plate; 33. Ring spring; 4. Elasticity adjustment component; 41. Rotating ring; 411. Threaded ring; 412. Through hole; 42. Drive rod; 421. Drive inclined surface; 5. Elastic component; 51. Drive spring; 52. Sliding block. Detailed Implementation

[0026] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the following description is provided in conjunction with the appendix. Figure 1-5 This application will be described in further detail.

[0027] This utility model embodiment provides a steel pipe expansion device, referring to... Figures 1 to 3The steel pipe expansion device includes a support platform 1 and an expansion mechanism. The expansion mechanism includes a mounting base 2, an expansion die cone 3, and an elastic force adjustment component 4. The mounting base 2 is fixedly connected to the support platform 1. The expansion die cone 3 is a rotating body and includes multiple arc-shaped expansion units 31. These units have identical structures and are slidably connected to the mounting base 2 along their respective radial directions. To expand the steel pipe, the pipe is inserted into the expansion die cone 3, and then the multiple expansion units 31 are driven to move outward synchronously along the corresponding radial direction of the mounting base 2. The mounting base 2 has the same number of elastic components 5 as the expansion units 31. Multiple sets of elastic components 5 correspond one-to-one with the multiple expansion units 31. The elastic components 5 are adapted to drive the corresponding expansion unit 31 towards the axis of the mounting base 2 to reset the expansion unit 31. The elastic force adjustment component 4 is movably connected to the mounting base 2 to simultaneously adjust the elastic force applied by the multiple elastic components 5 to the corresponding expansion unit 31. The mounting base 2 is fixedly connected to the support platform 1 by bolts. The expansion tube cone 3 and the elastic adjustment component 4 are connected to the mounting base 2 to form a module. When replacing the corresponding module, simply remove the mounting base 2.

[0028] The tube expanding mechanism has two intervals, differing only in the outer diameter of the expanding die cone 3 (one has a larger outer diameter, the other a smaller one); all other structures are identical. When expanding the same steel pipe, the pipe needs to pass through both expanding mechanisms sequentially. The smaller-diameter expanding mechanism first expands the pipe, and then the larger-diameter expanding mechanism directly expands the pipe to the required outer diameter. This two-stage expanding method avoids cracking caused by a large single-stage expansion, reducing waste and improving the quality of the expanding process. The following explanation uses the assembly structure of the components in one expanding mechanism as an example.

[0029] Reference Figures 1 to 3 A hydraulic cylinder 11 is bolted to the bottom of the support platform 1. The telescopic rod of the hydraulic cylinder 11 passes through the support platform 1 and is located below the mounting base 2. A tapered column is threaded onto the telescopic rod of the hydraulic cylinder 11. A tapered hole is provided inside the expansion die cone 3, which penetrates the expansion die cone 3 vertically. The smaller end of the tapered hole is located at the top, and the tapered column is inserted into the tapered hole. When the hydraulic cylinder 11 drives the telescopic rod to move the tapered column upward, multiple expansion units 31 move outward and expand under the drive of the tapered column.

[0030] Reference Figures 3 to 5The mounting base 2 has a circular groove 21 at its bottom, and a insertion hole 22 is formed at the bottom of the groove 21. The insertion hole 22 penetrates the mounting base 2, and its diameter is smaller than that of the groove 21. The expansion tube cone 3 is inserted into the insertion hole 22, with its axis coinciding with the axis of the insertion hole 22. The top of the expansion tube cone 3 passes through the insertion hole 22 and is located at the top of the mounting base 2. When multiple expansion tube units 31 of the expansion tube cone 3 are fitted together, the expansion tube cone 3 and the insertion hole 22 are in clearance fit, which facilitates the insertion of the steel pipe into the insertion hole 22 and its fitting onto the expansion tube cone 3, while reserving space for the steel pipe after flaring.

[0031] Multiple expansion tube units 31 have the same structure; the following description uses the structure of a single expansion tube unit 31 as an example. A sector-shaped plate 32 is integrally formed on the outer wall of the bottom of the expansion tube unit 31. When multiple expansion tube units 31 are attached together, the outer diameter of the sector-shaped plate 32 is larger than the diameter of the insertion hole 22. The sector-shaped plate 32 acts as a barrier, preventing the expansion tube unit 31 from being pulled out of the insertion hole 22 vertically. The outer wall of the sector-shaped plate 32 is spaced apart from the groove wall of the circular groove 21, thus providing sliding space for the sector-shaped plate 32.

[0032] Reference Figures 3 to 5 The elastic component 5 cooperates with the sector plate 32, and applies elastic force to the sector plate 32 to drive the expansion tube unit 31 to move. The outer diameter of the upper side of the expansion tube die cone 3 is smaller than the outer diameter of the lower side, which improves the smoothness of the steel tube being sleeved on the expansion tube die cone 3. Since the elastic component 5 applies an elastic driving force to the sector plate 32, a ring spring 33 is sleeved on the upper side of the expansion tube die cone 3. The outer diameter of the ring spring 33 is smaller than the inner diameter of the steel tube. The ring spring 33 and the elastic component 5 apply a reset elastic force to the upper and lower sides of the expansion tube unit 31 respectively, which improves the smoothness of the expansion tube unit 31 when resetting.

[0033] A support base plate 23 is installed inside the circular groove 21. The cross-section of the support base plate 23 is similar to a "7". A through hole is formed on the support base plate 23 to allow the conical column to pass through. The diameter of the through hole is smaller than the outer diameter of the sector plate 32, preventing the expansion tube unit 31 from moving vertically. The support base plate 23 is fixed to the groove wall of the circular groove 21 by bolts. Positioning guide posts are welded to the top of the support base plate 23. The number of positioning guide posts is the same as the number of sector plates 32 and they correspond one-to-one. An elongated hole is formed on the sector plate 32. The length of the elongated hole is radially opposite to that of the mounting base 2. The positioning guide posts are inserted into the elongated hole but do not protrude, allowing the sector plate 32 to drive the expansion tube unit 31 to move stably radially along the mounting base 2. The expansion tube die cone 3, under the action of the support base plate 23, forms a module with the mounting base 2.

[0034] Reference Figures 3 to 5The circular groove 21 has transverse sliding grooves 24 spaced out circumferentially, the same number as the elastic components 5, and corresponding one-to-one. The elastic component 5 includes a drive spring 51 and a sliding block 52, with the sliding block 52 slidably inserted into the transverse sliding groove 24. Spring grooves are provided on both the side of the sliding block 52 near the corresponding sector plate 32 and the side of the sector plate 32 near the sliding block 52. The two ends of the drive spring 51 are respectively inserted into the spring grooves of the sliding block 52 and the sector plate 32, and respectively abut against the sliding block 52 and the sector plate 32, thereby ensuring that the expansion tube unit 31 always has a tendency to move closer to the axis of the mounting base 2.

[0035] Reference Figures 3 to 5 The elastic adjustment component 4 includes a rotating ring 41 and drive rods 42. The number of drive rods 42 is the same as the number of sliding blocks 52 and they correspond one-to-one. The drive rods 42 are slidably connected to the mounting base 2 in the vertical direction. The rotating ring 41 is threaded onto the bottom of the mounting base 2, and the multiple drive rods 42 are in contact with the top of the rotating ring 41. After the rotating ring 41 is driven to rotate relative to the mounting base 2, the rotating component will drive the multiple drive rods 42 to move upward. The drive rods 42 will then drive the corresponding sliding blocks 52 to move towards the sector plate 32 to compress the drive spring 51.

[0036] Reference Figures 3 to 5 Specifically, the bottom of the mounting base 2 has vertical sliding grooves 25, the number of which is the same as the number of horizontal sliding grooves 24 and they correspond one-to-one. The vertical sliding grooves 25 are located at the end of the corresponding horizontal sliding grooves 24 away from the sector plate 32 and are connected to the horizontal sliding grooves 24. The corresponding drive rod 42 is slidably inserted into the vertical sliding groove 25. The top of the drive rod 42 has a drive inclined surface 421, which gradually slopes towards the sliding block 52 from top to bottom. The side of the sliding block 52 closest to the drive rod 42 is inserted into the vertical sliding groove 25 and has a mating inclined surface that fits against the drive inclined surface 421. The bottom of the mounting base 2 has a groove 26 for a threaded ring 411. The top of the rotating ring 41 is integrally formed with a threaded ring 411. The outer diameter of the threaded ring 411 is smaller than the outer diameter of the rotating ring 41. The drive rod 42 is located outside the threaded ring 411 and abuts against the top of the rotating ring 41. The threaded ring 411 is threadedly installed in the groove 26 of the threaded ring 411. Therefore, rotating the rotating ring 41 can drive multiple drive rods 42 to move upward.

[0037] The outer wall of the rotating ring 41 is provided with multiple through holes 412 spaced apart circumferentially. The through holes 412 pass through the rotating ring 41. When driving the rotating ring 41 to rotate, the operator can insert the drive rod 42 into the corresponding through hole 412 to drive the rotating ring 41 to rotate more easily. In order to prevent the rotating ring 41 from loosening due to vibration and causing the drive rod 42 to move, the threaded ring 411 is wrapped with thread-locking tape before the threaded ring 411 is installed in the threaded ring 411 groove 26, thereby increasing the friction and preventing loosening.

[0038] The implementation principle of the steel pipe expansion device in this application embodiment is as follows: During expansion, the expansion mechanism with a smaller outer diameter first expands the steel pipe, and then another expansion mechanism with a larger outer diameter directly expands the steel pipe to the required outer diameter. This two-stage expansion method avoids cracking of the steel pipe due to a large single-stage expansion. Each expansion unit 31 has an individual elastic component 5 to drive the expansion unit 31 to reset, making the reset of each expansion unit 31 more stable. If the elastic force applied by the elastic component 5 to the expansion unit 31 during reset decreases, the rotating ring 41 can be driven to rotate relative to the mounting base 2. The rotating component will then drive multiple drive rods 42 upwards, and the drive rods 42 will drive the corresponding sliding blocks 52 to move closer to the sector plate 32, compressing the drive spring 51 and causing the drive spring 51 to undergo greater elastic deformation, generating a greater elastic driving force. After the rotating ring 41 rotates, multiple elastic components 5 can be adjusted simultaneously. Compared to adjusting each elastic component 5 individually, this forms a modular adjustment structure, improving the convenience of adjustment.

[0039] Similarly, the components included in the "components," "mechanisms," and "devices" of this disclosure can also be flexibly combined. They can be modularly produced according to actual needs and assembled as an independent module; or they can be assembled separately to form a module in this device. The division of the above-mentioned components in this disclosure is only one embodiment for ease of reading and is not intended to limit the scope of protection of this disclosure. Any technical solution that includes the above-mentioned components and has the same function should be understood as an equivalent technical solution of this disclosure.

[0040] In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0041] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0043] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] It should be noted that when a component is referred to as "fixed to," "set on," "fixed to," or "mounted on" another component, it can be directly on the other component or there may be an intervening component. When a component is considered to be "connected to another component," it can be directly connected to the other component or there may be an intervening component. Furthermore, when a component is considered to be "fixedly connected" to another component, the connection can be detachable or non-detachable, such as through socketing, snap-fitting, integral molding, welding, etc., which are achievable in conventional technologies and will not be elaborated upon here.

[0045] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] The above embodiments are merely illustrative of several implementation methods of this disclosure, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this disclosure, and these modifications and improvements all fall within the protection scope of this disclosure.

Claims

1. A steel pipe expansion device, characterized in that: The device includes a support platform (1) and a tube expanding mechanism. The tube expanding mechanism includes a mounting base (2), a tube expanding die cone (3), and a spring adjustment assembly (4). The mounting base (2) is fixedly connected to the support platform (1). The tube expanding die cone (3) is a rotating body and includes multiple arc-shaped tube expanding units (31). The multiple tube expanding units (31) are slidably connected to the mounting base (2) along the radial direction corresponding to the mounting base (2). The mounting base (2) has the same number of tube expanding units (31) as the mounting base (2). The elastic component (5) is provided, and multiple sets of the elastic components (5) correspond one-to-one with multiple expansion tube units (31). The elastic component (5) is adapted to drive the corresponding expansion tube unit (31) to move closer to the axis of the mounting base (2). The elastic force adjustment component (4) includes a rotating ring (41) threadedly connected to the mounting base (2). After the rotating ring (41) is driven to rotate relative to the mounting base (2), it is adapted to simultaneously adjust the elastic force applied by multiple elastic components (5) to the corresponding expansion tube unit (31).

2. The steel pipe expansion device according to claim 1, characterized in that: The tube expansion mechanism is provided in two intervals. The outer diameter of the tube expansion die cone (3) in the two tube expansion mechanisms is different. The steel pipe needs to be processed by the two tube expansion mechanisms in sequence.

3. The steel pipe expansion device according to claim 1, characterized in that: The expansion tube die cone (3) has a tapered hole inside, and the tapered hole penetrates the expansion tube die cone (3) in the vertical direction.

4. The steel pipe expansion device according to claim 1, characterized in that: The outer diameter of the upper side of the expansion die cone (3) is smaller than the outer diameter of the lower side. A ring spring (33) is sleeved on the upper side of the expansion die cone (3). The outer diameter of the ring spring (33) is smaller than the inner diameter of the steel pipe.

5. The steel pipe expansion device according to any one of claims 1-4, characterized in that: The mounting base (2) has a circular groove (21) at its bottom, and a insertion hole (22) is provided at the bottom of the circular groove (21). The insertion hole (22) penetrates the mounting base (2), and the diameter of the insertion hole (22) is smaller than the diameter of the circular groove (21). The expansion tube die cone (3) is inserted into the insertion hole (22) and is clearance-fitted with the insertion hole (22). Each expansion tube unit (31) has a fan-shaped plate (32) integrally formed at its bottom, and the outer diameter of the fan-shaped plate (32) is larger than the diameter of the insertion hole (22).

6. The steel pipe expansion device according to claim 5, characterized in that: A support base plate (23) is fixedly installed in the circular groove (21). The top of the support base plate (23) is provided with a positioning guide post. A long waist hole is opened on the fan-shaped plate (32). The length direction of the long waist hole is the radial direction of the mounting round seat (2). The positioning guide post is inserted into the long waist hole.

7. The steel pipe expansion device according to claim 5, characterized in that: The circular groove (21) has a transverse sliding groove (24) on its wall. The elastic component (5) includes a drive spring (51) and a sliding block (52). The sliding block (52) is slidably inserted into the transverse sliding groove (24). The two ends of the drive spring (51) abut against the sliding block (52) and the sector plate (32) respectively.

8. The steel pipe expansion device according to claim 7, characterized in that: The elastic adjustment assembly (4) also includes a drive rod (42). The bottom of the mounting round base (2) is provided with a vertical sliding groove (25) that communicates with the horizontal sliding groove (24). The vertical sliding groove (25) is located at the end of the horizontal sliding groove (24) away from the sector plate (32). The drive rod (42) is slidably inserted into the vertical sliding groove (25). One end of the sliding block (52) is inserted into the vertical sliding groove (25) and contacts the drive rod (42). The rotating ring (41) is threaded to the bottom of the mounting round base (2). The drive rod (42) is located at the top of the rotating ring (41). When the rotating ring (41) rotates, it will drive the drive rod (42) to rise in the vertical sliding groove (25) to drive the sliding block (52) to move towards the side closer to the sector plate (32).

9. The steel pipe expansion device according to claim 8, characterized in that: The top of the drive rod (42) is provided with a drive ramp (421), and the sliding block (52) is provided with a mating ramp that fits against the drive ramp (421) on the side near the drive rod (42).

10. The steel pipe expansion device according to claim 8, characterized in that: The mounting base (2) has a threaded ring (411) groove (26) at its bottom. The rotating ring (41) has a threaded ring (411) fixedly mounted on its top. The outer diameter of the threaded ring (411) is smaller than the outer diameter of the rotating ring (41). The drive rod (42) is located outside the threaded ring (411). The threaded ring (411) is threadedly installed in the threaded ring (411) groove (26).

Images