CN213033916U

CN213033916U - Pipe centering and clamping device

Info

Publication number: CN213033916U
Application number: CN202021915738.8U
Authority: CN
Inventors: 曹向荣
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-09-04
Filing date: 2020-09-04
Publication date: 2021-04-23
Anticipated expiration: 2030-09-04

Abstract

The utility model provides a clamping device is well decided to tubular product relates to machining technical field. A pipe centering and clamping device comprises a positioning assembly and a rotating assembly, wherein the positioning assembly comprises a first centering mechanism and a second centering mechanism. The first centering mechanism comprises a cylinder body, a push rod and an inner expansion block, the cylinder body is sleeved on the push rod, and one end of the inner expansion block extends into the cylinder body and is connected with the push rod in a tensioning mode. The barrel sets up on runner assembly, and runner assembly can drive the barrel and rotate. The second centering mechanism comprises a clamping seat and a limiting structure, the clamping seat is arranged on the rotating assembly, and the limiting structure is arranged in the clamping seat. The rotating component can drive the cylinder body and the clamping seat to synchronously rotate. The pipe centering and clamping device can clamp the inner wall of a pipe from the inside, perform centering for the first time, and perform centering for the second time through the limiting structure. The centering inaccuracy caused by the fact that the pipe is not located at the rotation center can be avoided. The device has the advantages of small rotational inertia and high rotational speed, and can improve the processing rate of the pipe.

Description

Pipe centering and clamping device

Technical Field

The utility model relates to a machinery processing technology field particularly, relates to a clamping device is decide to tubular product.

Background

The pipe laser cutting machine is mainly used for cutting various hollow pipes made of metal or nonmetal materials, such as various welded pipes, seamless pipes, angle steel, channel steel and other industrial and civil materials. At present, laser cutting machines on the market are all widely used, and the pipe laser cutting machine is used for precisely processing and cutting metal round pipes, square pipes and the like. The pipe laser cutting machine has the following advantages: the cutting pipe has multiple types, and can cut, punch, carve and chamfer the pipe wall and the like of materials such as round pipes, square pipes, flat pipes and the like; the laser processing speed is high, the cutting precision is high, and large-batch high-efficiency processing can be realized; the operation is simple; and a numerical control operation platform is adopted, and corresponding drawings are input, so that the rapid machining can be realized, and the operation is flexible and rapid. At present, the current laser cutting equipment generally chooses the four-jaw chuck for use as the clamping tool who presss from both sides tight tubular product, and pneumatic or electronic chuck adopts and presss from both sides tightly from the tubular product outside, generally can bring the uncertainty, and the chuck can appear the asynchronous condition at the in-process of pressing from both sides tightly repeatedly and unclamping, causes the steel pipe not at rotation center, influences the machining precision of tubular product. Meanwhile, the pneumatic or electric chuck has large moment of inertia and slow rotation speed, and the rotation processing rate is influenced.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a clamping device is surely put to tubular product, it can follow the inside and press from both sides tightly the tubular product inner wall, carries out for the first time surely, can also carry out for the second time through limit structure surely. Because two kinds of mechanisms of centering all adjust according to specific tubular product overall dimension, it is fixed unchangeable for same overall dimension centering mechanism size, it can avoid the steel pipe not in the rotation center to lead to centering inaccurate condition to take place, very big promotion tubular product machining precision. Meanwhile, the device is small in rotational inertia and high in rotating speed, and the rotating processing speed of the pipe can be improved.

The embodiment of the utility model is realized like this:

the embodiment of the application provides a pipe centering and clamping device, which comprises a positioning assembly and a rotating assembly, wherein the positioning assembly comprises a first centering mechanism and a second centering mechanism;

the first centering mechanism comprises a cylinder body, a push rod and an inner expansion block, the cylinder body is sleeved on the push rod, and one end of the inner expansion block extends into the cylinder body and is connected with the push rod in a tensioning manner;

the cylinder body is arranged on the rotating assembly, and the rotating assembly can drive the cylinder body to rotate;

the second centering mechanism comprises a clamping seat and a limiting structure, the clamping seat is arranged on the rotating assembly, and the limiting structure is arranged in the clamping seat;

the rotating component can drive the cylinder body and the clamping seat to synchronously rotate.

In some embodiments of the present invention, the rotating assembly includes a first rotating mechanism and a second rotating mechanism, the center line of rotation of which coincides with each other, one end of the barrel is fixed on the first rotating mechanism, and the holder is fixed on the second rotating mechanism.

In some embodiments of the present invention, the first rotating mechanism and the second rotating mechanism are both connected to a driving motor, and the driving motor can rotate synchronously.

The utility model discloses an in some embodiments, above-mentioned limit structure includes a plurality of stoppers, and the stopper includes two spacing axles and two size adjustment pieces, and spacing axle parallel sets up relatively in the cassette, and just spacing axle both ends are passed through the bearing and are fixed respectively on two size adjustment pieces.

In some embodiments of the present invention, the limiting structure includes a plurality of limiting devices sequentially disposed.

In some embodiments of the present invention, the limiting shaft is a cylindrical structure.

In some embodiments of the present invention, the limiting shaft is an arc-shaped structure.

The utility model discloses an in some embodiments, the above-mentioned push rod end of keeping away from the internal expanding piece is provided with thrust unit, and thrust unit includes cylinder, driving lever and support rib plate, and the driving lever middle part is fixed and support rib plate hinged joint, the one end of driving lever and the piston rod hinged joint of cylinder, the other end and the push rod of driving lever are connected.

In some embodiments of the present invention, the inner expanding block is an elastic claw structure, a central hole is formed in the elastic claw structure, an inner surface of the central hole is a conical surface, and the push rod can extend into the central hole and slide along the conical surface.

Compared with the prior art, the embodiment of the utility model has following advantage or beneficial effect at least:

the utility model provides a clamping device is well decided to tubular product, including locating component and runner assembly. Wherein, locating component mainly used fixes a position and spacing to the pipe fitting center, prevents that tubular product from appearing quivering, influences the center location. The rotating assembly is used for clamping the pipe, so that the pipe cannot move relatively, and the pipe is ensured to be on a processing center line. The rotating assembly is used for driving the positioning assembly to rotate synchronously, and the pipe can be conveniently machined in a rotating mode. The positioning assembly comprises a first centering mechanism and a second centering mechanism; the first centering mechanism comprises a cylinder body, a push rod and an inner expansion block, the cylinder body is sleeved on the push rod, and one end of the inner expansion block extends into the cylinder body and is connected with the push rod in a tensioning mode. The pipe is sleeved on the barrel, the push rod can push the inner expansion block to enable the inner expansion block to expand under stress, the inner expansion block can expand under stress, and the inner expansion block can expand under stress to enable the inner expansion block to expand the pipe wall from the inner wall of the pipe, so that the pipe is clamped. In the clamping process, the pipe is always kept at the processing center line, and the internal expansion type centering clamping of the pipe can be completed. The pipe is clamped by using an internal expansion block type clamping principle, the situation that the steel pipe is not at a rotating center and the center positioning is inaccurate can be avoided after clamping, and the machining precision can be improved. Wherein, the barrel sets up on rotating assembly, and rotating assembly can drive the barrel and rotate. The rotating assembly drives the barrel to rotate, so that the barrel can drive the pipe to rotate, and rotary processing is realized. The second centering mechanism comprises a clamping seat and a limiting structure, the clamping seat is arranged on the rotating assembly, and the limiting structure is arranged in the clamping seat. The clamping seat is mainly used for bearing the limiting structure, so that the limiting structure can be accurately installed on a machining center line. The cassette sets up on rotating assembly, can make the rotation of cassette and the rotation synchronization of barrel, prevents that the tubular product from rotating asynchronous around causing the deformation. The rotating assembly can drive the barrel and the clamping seat to rotate synchronously, and when the pipe fitting is machined, the pipe fitting is prevented from rotating asynchronously, so that the pipe fitting is prevented from being deformed and damaged.

Therefore, the pipe centering and clamping device can clamp the inner wall of the pipe from the inside, perform primary centering and perform secondary centering through the limiting structure. The centering device can avoid the situation that the steel pipe is not centered accurately due to the fact that the steel pipe is not at the rotating center, and greatly improves the machining precision of the pipe. Meanwhile, the device is small in rotational inertia and high in rotating speed, and the rotating processing speed of the pipe can be improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic structural diagram of an embodiment of the present invention;

fig. 2 is a schematic three-dimensional structure diagram of an embodiment of the present invention;

fig. 3 is a side view of an embodiment of the invention;

fig. 4 is an exploded view of the positioning assembly according to the embodiment of the present invention.

Icon: 1-deflector rod, 2-cylinder, 3-support rib plate, 4-push rod, 5-ball stud, 6-internal expansion block, 7-cylinder, 8-driving motor, 9-first rotating mechanism, 10-second rotating mechanism, 11-clamping seat, 12-adjusting bolt, 13-fixing bolt, 14-adjusting block, 15-limiting shaft, 16-bearing and 17-pipe.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the drawings in the embodiments of the present invention are combined below to clearly and completely describe the technical solutions in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, and the gear is not all embodiments. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that, if the terms "center", "upper", "lower", "horizontal", "vertical", "inner", etc. indicate the position or positional relationship based on the position or positional relationship shown in the drawings, or the position or positional relationship that the products of the present invention are usually placed when in use, the description is only for convenience of description and simplification, but the indication or suggestion that the device or element to which the description refers must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be interpreted as limiting the present invention. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not require that the assembly be absolutely horizontal or overhang, but that the vertical may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the embodiments of the present invention, "a plurality" means at least 2.

In the description of the embodiments of the present invention, it should be further noted that unless explicitly stated or limited otherwise, the terms "disposed," "mounted," and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Examples

Referring to fig. 1 and fig. 2, fig. 1 is a schematic structural diagram of an embodiment of the present invention, and fig. 2 is a schematic three-dimensional structural diagram of an embodiment of the present invention. This embodiment provides the utility model provides a clamping device is well known to tubular product, including locating component and runner assembly. Wherein, locating component mainly used fixes a position and spacing to the pipe fitting center, prevents that tubular product 17 from appearing quivering, influences the center location. The rotating assembly is used for clamping the pipe 17, so that the pipe 17 cannot move relatively, and the pipe 17 is ensured to be on a processing center line. The rotating assembly is used for driving the positioning assembly to rotate synchronously, so that the pipe 17 can be conveniently rotated and processed. The positioning assembly comprises a first centering mechanism and a second centering mechanism; the first centering mechanism comprises a cylinder body 7, a push rod 4 and an inner expansion block 6, wherein the cylinder body 7 is sleeved on the push rod 4, and one end of the inner expansion block 6 extends into the cylinder body 7 and is connected with the push rod 4 in a tensioning mode. The tube 17 is sleeved on the cylinder 7, the push rod 4 can push the inner expansion block 6 to enable the inner expansion block 6 to expand under stress, the inner expansion block 6 can expand under stress, and the inner expansion block 6 can expand under stress to enable the inner expansion block 6 to expand the tube wall from the inner wall of the tube 17, so that the tube 17 is clamped. In the clamping process, the pipe 17 is always kept at the machining center line, and the internal expansion type centering clamping of the pipe 17 can be completed. The pipe 17 is clamped by using the internal expansion block 6 type clamping principle, the situation that the steel pipe is not at the rotating center and the center positioning is inaccurate can be avoided after clamping, and the processing precision can be improved. Wherein, barrel 7 sets up on rotating assembly, and rotating assembly can drive barrel 7 and rotate.

The rotating assembly drives the barrel 7 to rotate, so that the barrel 7 drives the pipe 17 to rotate, and rotary machining is realized. The second centering mechanism comprises a clamping seat 11 and a limiting structure, wherein the clamping seat 11 is arranged on the rotating assembly through a fixing bolt 13, and the limiting structure is arranged in the clamping seat 11. The clamping seat 11 is mainly used for bearing a limiting structure, so that the limiting structure can be accurately installed on a machining center line. The clamping seat 11 is arranged on the rotating assembly, so that the rotation of the clamping seat 11 and the rotation of the barrel 7 are synchronous, and the deformation caused by the asynchronous front and back rotation of the pipe 17 is prevented.

The rotating assembly can drive the barrel 7 and the clamping seat 11 to rotate synchronously, and when the pipe fitting is machined, the phenomenon that the pipe fitting 17 is deformed and damaged due to asynchronous rotation is avoided.

Therefore, the pipe centering and clamping device can clamp the inner wall of the pipe 17 from the inside, perform primary centering and perform secondary centering through a limiting structure. The centering device can avoid the situation that the steel pipe is not centered in the rotation center, and greatly improves the machining precision of the pipe 17. Meanwhile, the device is small in rotational inertia and high in rotating speed, and the rotating processing speed of the pipe 17 can be improved.

In some embodiments of this embodiment, the rotating assembly includes a first rotating mechanism 9 and a second rotating mechanism 10 whose rotation center lines coincide with each other, one end of the cylinder 7 is fixed on the first rotating mechanism 9, and the cartridge 11 is fixed on the second rotating mechanism 10. The first rotating mechanism 9 is used for driving the cylinder 7 to rotate, so as to drive the pipe 17 on the cylinder 7 to rotate. The second rotating mechanism 10 is used for driving the card seat 11 to rotate, so as to drive the limiting structure on the card seat 11 to rotate.

In some embodiments of the present embodiment, the driving motor 8 is connected to both the first rotating mechanism 9 and the second rotating mechanism 10, and the driving motor 8 rotates synchronously. The first rotating mechanism 9 is used for driving the cylinder 7 to rotate so as to drive the core rod to rotate, the second rotating mechanism 10 is used for driving the clamping seat 11 to rotate so as to drive the limiting mechanism to rotate, and the first rotating mechanism 10 and the second rotating mechanism 10 rotate synchronously.

In this embodiment, the first rotating mechanism 9 includes a gear, and the cylinder 7 passes through the gear and is fixedly connected with the gear. In this embodiment, the cylinder 7 is connected with the gear through a flange, and the cylinder 7 can rotate along with the gear during the rotation of the gear. The output shaft of the motor is connected with a transmission gear, and the transmission gear is meshed with the gear. Also, in the present embodiment, the second transmission mechanism is substantially the same as the first rotation mechanism.

In some embodiments of this embodiment, the limiting structure includes a plurality of limiting devices, each limiting device includes two limiting shafts 15 and two size adjusting blocks 14, the limiting shafts 15 are oppositely disposed in parallel in the clamping seat 11, and two ends of the limiting shafts 15 are respectively fixed on the two adjusting blocks 14 through bearings 16. The tubular product 17 of processing sets up between two spacing axles 15, can restrict through spacing axle 15 by processing tubular product 17 in radial movement, causes the condition emergence that tubular product 17 center takes place to beat. The adjusting block 14 is mainly used for fixing the limiting shaft 15 on the clamping seat 11, so that the limiting shaft 15 can freely rotate on the adjusting block 14, and the machined pipe 17 can move in the axial direction.

Referring to fig. 3 and 4, in some embodiments of the present invention, the limiting structure includes three limiting devices sequentially disposed, and the limiting device located in the middle is perpendicular to the limiting devices located at two sides. In this embodiment, the direction of the middle stopper is different from the direction of the stoppers on both sides, the middle stopper is in a vertical state, and the stoppers on both sides are in a horizontal state, so that the pipe 17 to be processed can be limited to move in each radial direction, the center stability of the pipe 17 to be processed is ensured, and the pipe does not jump.

Referring to fig. 4, in some embodiments of the present invention, an adjusting bolt 12 is disposed between the adjusting block 14 and the clamping seat 11, one end of the adjusting bolt 12 passes through the clamping seat 11 and is rotatably connected to the adjusting block 14, and the adjusting bolt 12 is in threaded connection with the clamping seat 11. The adjusting bolt 12 is used to adjust the position of the adjusting block 14, which can be adjusted by turning the adjusting bolt 12.

In some embodiments, the limiting shaft 15 has a cylindrical structure. The limiting shafts 15 with cylindrical structures are selected, a square channel is formed among the three limiting shafts 15, and the square channel is suitable for positioning and limiting the square pipe 17. Make spacing axle 15 laminate on square tubular product 17's pipe wall, promotion location accuracy that can be very big can also prevent that tubular product 17 from appearing the condition of beating in man-hour.

In some embodiments of the present embodiment, a thrust mechanism is disposed at the end of the push rod 4 away from the inner expanding block 6, the thrust mechanism includes an air cylinder 2, a shift lever 1 and a support rib plate 3, the middle portion of the shift lever 1 is fixed and hinged to the support rib plate 3, one end of the shift lever 1 is hinged to a piston rod of the air cylinder 2, and the other end of the shift lever 1 is connected to the push rod 4. The pushing structure is mainly used for pushing the push rod 4 to move, wherein a piston rod of the cylinder 2 can push or pull one end of the shift lever 1, so that the shift lever 1 drives the other end to push or pull the push rod 4, and the push rod 4 is driven to move in the cylinder 7.

In some embodiments of the present invention, the inner expanding block 6 is a resilient claw-shaped structure (not shown), a central hole is formed in the resilient claw-shaped structure, an inner surface of the central hole is a tapered surface (not shown), and the push rod 4 can extend into the central hole and slide along the tapered surface. In this embodiment, the end of the push rod 4 is provided with a ball stud 5, and one end of the ball stud 5 slides along the conical surface. After the push rod 4 enters the central hole, the push rod moves forwards, one end of the push rod 4 slides along the conical surface, the clamping jaw is continuously pushed tightly, the clamping jaw is tensioned towards the inner wall of the processed pipe 17, and the main processed pipe 17 is clamped. The inner expansion block 6 is made of elastic material, the end surface is provided with a symmetrical groove structure with a certain depth and a central hole, the inner surface of the central hole is a conical surface, and the push rod 4 can extend into the central hole and slide along the conical surface.

When the pipe machining device is used, a pipe to be machined 17 penetrates through the limiting shaft 15 on the clamping seat 11, the limiting shaft 15 is arranged to be tightly attached to the pipe to be machined 17, the pipe to be machined 17 can move in the axial direction and cannot move in the radial direction, and therefore the central positioning of the pipe to be machined 17 is guaranteed to be unchanged. Sleeving a processed pipe 17 on the barrel 7, starting the cylinder 2, enabling a piston rod of the cylinder 2 to push one end of the deflector rod 1, and enabling the other end of the deflector rod 1 to push the push rod 4. The push rod 4 moves towards the direction of the inner expanding block 6, one end of the push rod 4 enters the central hole, one end of the push rod 4 slides along the inner surface of the central hole, the push rod 4 slides along the conical surface in the central hole, the elastic clamping jaws tightly expand the pipe 17 on the cylinder body 7, and therefore the processed pipe 17 is clamped. After clamping is completed, the first rotating mechanism and the second rotating mechanism are started to enable the driving motor 8 to synchronously drive the first rotating mechanism and the second rotating mechanism to rotate, and the pipe 17 at the front end and the rear end is ensured to rotate synchronously. The pipe 17 to be processed can be rotated to process according to the processing requirement of the pipe 17 to be processed.

To sum up, the embodiment of the utility model provides a clamping device is well decided to tubular product, including locating component and runner assembly. Wherein, locating component mainly used fixes a position and spacing to the pipe fitting center, prevents that tubular product 17 from appearing quivering, influences the center location. The rotating assembly is used for clamping the pipe 17, so that the pipe 17 cannot move relatively, and the pipe 17 is ensured to be on a processing center line. The rotating assembly is used for driving the positioning assembly to rotate synchronously, so that the pipe 17 can be conveniently rotated and processed. The positioning assembly comprises a first centering mechanism and a second centering mechanism; the first centering mechanism comprises a cylinder body 7, a push rod 4 and an inner expansion block 6, wherein the cylinder body 7 is sleeved on the push rod 4, and one end of the inner expansion block 6 extends into the cylinder body 7 and is connected with the push rod 4 in a tensioning mode. The tube 17 is sleeved on the cylinder 7, the push rod 4 can push the inner expansion block 6 to enable the inner expansion block 6 to expand under stress, the inner expansion block 6 can expand under stress, and the inner expansion block 6 can expand under stress to enable the inner expansion block 6 to expand the tube wall from the inner wall of the tube 17, so that the tube 17 is clamped. In the clamping process, the pipe 17 is always kept at the machining center line, and the internal expansion type centering clamping of the pipe 17 can be completed. The pipe 17 is clamped by using the internal expansion block 6 type clamping principle, the situation that the steel pipe is not at the rotating center and the center positioning is inaccurate can be avoided after clamping, and the processing precision can be improved. Wherein, barrel 7 sets up on rotating assembly, and rotating assembly can drive barrel 7 and rotate.

The rotating assembly drives the barrel 7 to rotate, so that the barrel 7 drives the pipe 17 to rotate, and rotary machining is realized. The second centering mechanism comprises a clamping seat 11 and a limiting structure, wherein the clamping seat 11 is arranged on the rotating assembly, and the limiting structure is arranged in the clamping seat 11. The clamping seat 11 is mainly used for bearing a limiting structure, so that the limiting structure can be accurately installed on a machining center line. The clamping seat 11 is arranged on the rotating assembly, so that the rotation of the clamping seat 11 and the rotation of the barrel 7 are synchronous, and the deformation caused by the asynchronous front and back rotation of the pipe 17 is prevented. The rotating assembly can drive the barrel 7 and the clamping seat 11 to rotate synchronously, and when the pipe fitting is machined, the phenomenon that the pipe fitting 17 is deformed and damaged due to asynchronous rotation is avoided.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The pipe centering and clamping device is characterized by comprising a positioning assembly and a rotating assembly, wherein the positioning assembly comprises a first centering mechanism and a second centering mechanism;

the first centering mechanism comprises a cylinder body, a push rod and an inner expansion block, the cylinder body is sleeved on the push rod, and one end of the inner expansion block extends into the cylinder body and is in tension connection with the push rod;

the rotating assembly can drive the cylinder and the clamping seat to rotate synchronously.

2. The tube centering and clamping device as recited in claim 1, wherein said rotating assembly includes a first rotating mechanism and a second rotating mechanism having coinciding center lines of rotation, one end of said cylinder being fixed to said first rotating mechanism, said cartridge being fixed to said second rotating mechanism.

3. The tube centering and clamping device as recited in claim 2, wherein a drive motor is connected to each of said first rotating mechanism and said second rotating mechanism, said drive motors being capable of synchronous rotation.

4. The tube centering and clamping device as claimed in claim 1, wherein the limiting structure comprises a plurality of limiting devices, each limiting device comprises two limiting shafts and two size adjusting blocks, the limiting shafts are oppositely arranged in the clamping seat in parallel, and two ends of each limiting shaft are respectively fixed on the two size adjusting blocks through bearings.

5. The tube centering and clamping device as recited in claim 4, wherein said limiting structure comprises three limiting devices arranged in sequence, and the limiting device in the middle is perpendicular to the limiting devices on both sides.

6. The tube centering and clamping device as recited in claim 4, wherein said restraint shaft is of cylindrical configuration.

7. The tube centering and clamping device as recited in claim 4, wherein said restraint shaft is of an arcuate configuration.

8. The pipe centering and clamping device according to claim 1, wherein a thrust mechanism is arranged at the end of the push rod far away from the inner expansion block, the thrust mechanism comprises an air cylinder, a shift rod and a support rib plate, the middle portion of the shift rod is fixedly connected with the support rib plate through a hinge, one end of the shift rod is connected with a piston rod of the air cylinder through a hinge, and the other end of the shift rod is connected with the push rod.

9. The tube centering and clamping device as claimed in claim 1, wherein said internal expanding block is a resilient claw structure, a central hole is formed in said resilient claw structure, an inner surface of said central hole is a tapered surface, and said push rod can extend into said central hole and slide along said tapered surface.