Symmetrical internal spiral thread round pipe and rolling forming integrated device thereof

Abstract

This invention discloses a symmetrical internally threaded round tube and its integrated rolling forming device, belonging to the field of round tube processing technology. Specifically, it includes a vertical plate and a rolling forming component and a three-axis opposing component symmetrically arranged between the vertical plates. By setting an externally rotating threading disc and an internally rotating threading disc in the same vertical plane, the two are synchronously rotated and axially fed under the control of the drive component, applying symmetrical rolling action to the inner and outer walls of the round tube at the same time. Combined with the radial clamping structure composed of an external support spring, an internal sliding block, a movable block and a fixed block inside the centering ring seat, it is ensured that the round tube is always subjected to uniformly distributed radial pressure in the entire circumferential direction, avoiding stress concentration caused by single tangential extrusion, improving the roundness and tube shape retention ability after internal thread processing. Furthermore, by setting an elastic follow-up support component, the round tube can be automatically centered and quickly clamped, suppressing vibration and axial movement caused by rotational feeding during processing.

Description

Technical Field

[0001] This invention relates to the field of round tube processing technology, specifically to a symmetrical internally threaded round tube and its integrated rolling forming device. Background Technology

[0002] In the field of machining, thread rolling has become an important process for threading hollow round tubes due to its advantages such as no cutting, high efficiency, and excellent thread surface performance. Thread rolling is formed by plastically flowing the material through cold extrusion. The radial compressive stress generated during the process can significantly improve the fatigue strength and torsional strength of the workpiece. It is an ideal forming method that is efficient and energy-saving. As the core equipment of this process, the rolling machine can be divided into two-axis rolling machines and three-axis rolling machines depending on the number of rolling shafts. The traditional two-axis rolling machine consists of two rolling shafts. During processing, the workpiece is placed between the two rolling shafts. The rotation of the rolling shafts drives the workpiece to rotate and applies radial extrusion force to the workpiece to achieve thread rolling.

[0003] However, since the two-axis rolling mill can only apply extrusion force to the workpiece from two opposite directions during operation, and the hollow round tube itself has a hollow structure and low radial stiffness, under the above-mentioned single tangential extrusion method, the compressive stress locally borne by the tube wall far exceeds the yield limit of the material, resulting in uneven radial stress on the tube body. After processing, it is very easy to cause local plastic deformation or even overall collapse, which seriously affects the roundness of the workpiece. In addition, it is also easy to cause processing defects such as uneven thread pitch and thread pitch diameter deviation. Therefore, a solution is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a symmetrical internal spiral threaded round tube and its integrated rolling forming device to solve the above-mentioned technical problems.

[0005] The present invention provides the following device: an integrated device for rolling forming of symmetrical internal spiral threaded round tube, comprising a vertical plate and a rolling forming component and a triaxial opposing component symmetrically arranged between the vertical plates; The roll forming assembly includes an outer spiral thread spool and an inner spiral thread spool located in the middle of the inner side of the vertical plate and in the same vertical plane. The axial movement and rotation of the outer spiral thread spool and the inner spiral thread spool together complete the thread roll forming of the round tube. The three-axis opposing assembly includes a centering ring seat located on the inner side of the circular tube near the outer spiral spool. The centering ring seat is a closed semi-ring structure with an open bottom. A fixed block is installed at the upper center of the inner ring side of the centering ring seat. Both ends of the fixed block are equipped with movable blocks through internal retraction springs. The center ring seat is longitudinally filled with an outer support spring, and a guide block is installed at the inner bottom of the center ring seat. Both ends of the outer support spring are equipped with an inner sliding block that slides with the guide block. The outer end of the inner sliding block extends to the inner ring side of the center ring seat and is connected to the movable block.

[0006] Furthermore, a base plate is installed at the bottom of the two upright plates, and a loading seat and a pressing seat are installed opposite each other on the base plate in the middle of the upright plates. A top plate is installed between the upper ends of the two upright plates, and cylinders for vertically driving the loading seat and the pressing seat are respectively installed in the middle of the base plate and the top plate.

[0007] Furthermore, a feeding plate is slidably mounted on both sides of the middle part of the upper surface of the substrate. The feeding plate is provided with a groove for intermittent feeding of round tubes, and the feeding seat and the lower pressure seat are provided with a support hole that matches the round tube.

[0008] Furthermore, a rotating seat connected to the vertical plate is installed on the outer side of the inner rotating screw. An elastic follow-up support assembly is provided on the side of the rotating seat near the round tube. The elastic follow-up support assembly includes a semi-open sleeve provided on the inner side of the rotating seat. The semi-open sleeve and the inner rotating screw form a support port for inserting and fixing the end of the round tube.

[0009] Furthermore, the outer circular array of the semi-open sleeve has compression springs, and the upper end of the compression springs is threaded with a rotating screw that is rotatably connected to the rotating seat.

[0010] Furthermore, the length of the bottom opening of the central ring seat is greater than the diameter of the round tube. When the round tube pushes the two movable blocks upward, the inner spring is compressed. When the round tube contacts the fixed block, the inner spring returns to its original position.

[0011] Furthermore, when the round tube is centered in the centering ring seat, the outer support spring always applies a radial pressing action on the round tube to the inner sliding block and the movable block.

[0012] Furthermore, each of the upright plates is fitted with a drive assembly in the middle, which is used to control the rotation axis movement of the outer and inner spinning discs respectively.

[0013] Furthermore, both the upright plate and the feeding plate are equipped with slide rail assemblies mounted on the bottom of the base plate, which are used to apply the axial movement of the upright plate and the longitudinal movement of the feeding plate.

[0014] One type of symmetrical internally threaded round tube includes a round tube fitting. The round tube fitting is hollow, and the inner and outer walls of both ends of the round tube fitting are respectively provided with internally threaded parts and externally threaded parts that cooperate with internally threaded discs and externally threaded discs.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. On the one hand, by setting an outer spiral thread spool and an inner spiral thread spool in the same vertical plane, the two are synchronously rotated and axially fed under the control of the drive component, and symmetrical rolling action is applied to the inner and outer walls of the round pipe at the same time. Combined with the radial clamping structure composed of the outer support spring, the inner sliding block, the movable block and the fixed block inside the centering ring seat, it is ensured that the round pipe is always subjected to uniformly distributed radial pressure in the entire circumferential direction, avoiding stress concentration caused by single tangential extrusion, and improving the roundness and pipe shape retention ability after internal thread processing.

[0016] 2. On the other hand, by setting up a semi-open sleeve, compression spring and rotating screw in the elastic follow-up support assembly, a flexible and adjustable support port is provided for the end of the round tube. At the same time, by using the linkage between the bottom opening of the centering ring seat and the movable block and the inner retraction spring, the automatic centering and rapid clamping of the round tube can be realized, suppressing the vibration and axial movement caused by the rotary feed during the processing, and ensuring the uniformity of the thread pitch and the processing accuracy of the thread pitch diameter. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a front view of the present invention; Figure 3 This is a front sectional view of the present invention; Figure 4 This is a schematic diagram of the installation structure of the roll forming assembly and the triaxial opposing assembly of the present invention; Figure 5 In this invention Figure 4 A structural breakdown diagram; Figure 6 This is a schematic diagram of the installation structure of the elastic follower support component of the present invention; Figure 7 This is a front view of the triaxial opposing component of the present invention; Figure 8 This is a structural diagram of the circular tube component of the present invention.

[0018] In the diagram: 1. Base plate; 2. Vertical plate; 3. Top plate; 4. Round tube; 5. Feeding seat; 6. Lower pressing seat; 7. Cylinder; 8. Rotating seat; 9. Outer spiral spool; 10. Centering ring seat; 11. Feeding plate; 12. Inner spiral spool; 13. Outer support spring; 14. Fixed block; 15. Movable block; 16. Inner retraction spring; 17. Half-open sleeve; 18. Rotating screw; 19. Compression spring; 20. Support port; 21. Guide block; 22. Inner retraction slider. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the following description is provided in conjunction with embodiments and appendices. Figure 1-8 The present invention will be further described in detail below. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0020] Example 1: The present invention proposes an integrated rolling forming device for symmetrical internal spiral threaded round tubes, including a vertical plate 2 and a rolling forming component and a triaxial opposing component symmetrically arranged between the vertical plates 2; The roll forming assembly includes an outer spiral thread spool 9 and an inner spiral thread spool 12 located in the middle of the inner side of the vertical plate 2 and in the same vertical plane. The axial movement and rotation of the outer spiral thread spool 9 and the inner spiral thread spool 12 together complete the thread roll forming of the round tube 4. The outer spiral thread spool 9 provides external radial support and rotational friction, while the inner spiral thread spool 12 forms internal threads on the inner wall of the round tube 4 by cold extrusion through the thread rolling die on its surface. Since the rolling pressure is applied simultaneously inside and outside, the tube wall of the round tube 4 is subjected to symmetrically distributed radial compressive stress, avoiding stress concentration caused by traditional unilateral extrusion.

[0021] The three-axis opposing assembly includes a centering ring seat 10 located on the inner side of the circular tube 4 near the outer spiral spool 9. The centering ring seat 10 is a closed semi-ring structure with an open bottom. A fixed block 14 is installed at the upper middle part of the inner ring side of the centering ring seat 10. Both ends of the fixed block 14 are equipped with movable blocks 15 through inward springs 16. The centering ring seat 10 is longitudinally filled with an outer support spring 13. A guide block 21 is installed at the inner bottom of the centering ring seat 10. Both ends of the outer support spring 13 are equipped with inward sliding blocks 22 that slide in cooperation with the guide block 21. The outer end of the inward sliding block 22 extends to the inner ring side of the centering ring seat 10 and is connected to the movable block 15. Specifically, when the round tube 4 enters through the bottom opening of the centering ring seat 10, the round tube 4 first squeezes the two movable blocks 15 to overcome the elastic force of the inner retraction spring 16 and move upward. After the round tube 4 is fully inserted and contacts the fixed block 14, the inner retraction spring 16 returns to its original position. At the same time, the outer support spring 13 applies a continuous and symmetrical clamping force to both radial sides of the round tube 4 through the inner retraction slider 22 and the movable block 15, thereby realizing the automatic centering and radial clamping of the round tube 4.

[0022] The outer side of the inner spiral screw spool 12 is equipped with a rotating seat 8 connected to the vertical plate 2. The side of the rotating seat 8 near the round tube 4 is provided with an elastic follower support assembly. The elastic follower support assembly includes a semi-open sleeve 17 provided inside the rotating seat 8. The semi-open sleeve 17 and the inner spiral screw spool 12 form a support port 20 for inserting and fixing the end of the round tube 4. The outer side of the semi-open sleeve 17 is distributed with a circular array of compression springs 19. The upper end of the compression springs 19 is threaded with a rotating screw 18 that is rotatably connected to the rotating seat 8. The middle part of the upright plate 2 is equipped with a drive assembly, which is used to control the rotation axis movement of the outer spinning spool 9 and the inner spinning spool 12 respectively. The bottom of the upright plate 2 and the feed plate 11 are equipped with a slide rail assembly on the upper side of the base plate 1, which is used to apply the axial movement of the upright plate 2 and the longitudinal movement of the feed plate 11.

[0023] The principle of symmetrical internal threaded round tube and its roll forming is as follows: The feeding plate 11 intermittently transports the round tube 4 to be processed to the processing station. The feeding seat 5 and the lower pressing seat 6 close and clamp the two ends of the round tube 4 under the drive of the cylinder 7. Then, the vertical plate 2 moves towards each other along the slide rail assembly, so that the outer spiral thread spool 9 and the inner spiral thread spool 12 approach the round tube 4. The round tube 4 first enters the centering ring seat 10 to complete automatic centering and radial pre-tightening. At the same time, the two ends of the round tube 4 are inserted into the support port 20 to obtain elastic follow-up support. The drive assembly is started, and the outer spiral thread spool 9 and the inner spiral thread spool 12 rotate synchronously and feed axially with a set pitch, rolling out continuous and uniform internal threads on the inner wall of the round tube 4. After processing, the components move in opposite directions, and the feeding plate 11 pushes out the finished product and feeds in the next round tube 4.

[0024] Example 2: A base plate 1 is installed at the bottom of two upright plates 2. A loading seat 5 and a pressing seat 6 are installed on the base plate 1 in the middle of the upright plates 2. A top plate 3 is installed between the upper ends of the two upright plates 2. A cylinder 7 for vertically driving the loading seat 5 and the pressing seat 6 is installed in the middle of the base plate 1 and the top plate 3 respectively. A feeding plate 11 is slidably mounted on both sides of the middle part of the upper surface of the substrate 1. The feeding plate 11 is provided with a groove for intermittent feeding of the round tube 4, and the feeding seat 5 and the lower pressure seat 6 are provided with a support hole that matches the round tube 4 at their close ends. During operation, the feeding plate 11 moves longitudinally to send the round tube 4 directly below the support hole. The feeding seat 5 and the lower pressure seat 6 close towards each other under the drive of the cylinder 7 to achieve stable clamping of the round tube 4.

[0025] The bottom opening length of the centering ring seat 10 is greater than the diameter of the round tube 4. When the round tube 4 presses against the two movable blocks 15 and moves upward, the inner spring 16 is compressed. When the round tube 4 contacts the fixed block 14, the inner spring 16 returns to its original position. When the round tube 4 is centered in the centering ring seat 10, the outer support spring 13 always applies a radial clamping action to the inner sliding block 22 and the movable block 15 on the round tube 4. This process realizes adaptive centering and clamping without an additional power source, and the clamping force is proportional to the compression of the outer support spring 13, ensuring that round tubes 4 with different diameter tolerances can obtain a suitable radial preload.

[0026] Example 3: Refer to Figures 1-8 As shown, this embodiment combines the technical content of Embodiment 1 and Embodiment 2 to form a processing method for a symmetrical internally threaded round tube: First, based on the diameter and thread specifications of the round tube 4 to be processed, the preload of the pressure spring 19 is adjusted by rotating the screw 18 so that the size of the support opening 20 between the semi-open sleeve 17 and the inner spiral thread spool 12 is adapted to the end of the round tube 4; at the same time, the rotation speed of the drive assembly and the axial feed pitch parameters are adjusted. Then, the round tube 4 is placed in the groove of the feeding plate 11 by the feeding device, preferably the conveyor roller. The device is started, and the feeding plate 11 moves longitudinally along the slide rail assembly, conveying the round tube 4 to the support hole position between the feeding seat 5 and the lower pressure seat 6. The upper cylinder 7 drives the feeding seat 5 to move downward, and the lower cylinder 7 drives the lower pressure seat 6 to move upward. After the two are closed, they clamp the two ends of the round tube 4 through the support hole. Next, the vertical plate 2 moves axially towards each other under the drive of the slide rail assembly, so that the outer spiral spool 9 and the inner spiral spool 12 gradually approach the round tube 4. The round tube 4 first enters the bottom opening of the centering ring seat 10, and its outer wall presses against the movable block 15 to compress the inner retraction spring 16. When the round tube 4 continues to move until it contacts the fixed block 14, the inner retraction spring 16 returns to its original position. At the same time, the outer support spring 13 pushes the inner retraction slider 22 and the movable block 15 to apply a radial centering clamping force to the round tube 4. Meanwhile, the two ends of the round tube 4 are inserted into the support port 20, and the semi-open sleeve 17 provides flexible support to the ends of the round tube 4 under the elastic force of the compression spring 19. Subsequently, the drive assembly is activated, and the outer spiral thread spool 9 and the inner spiral thread spool 12 rotate synchronously with the same angular velocity and the same axial feed speed. The outer spiral thread spool 9 applies rotational friction force to the outer wall of the circular tube 4 and provides auxiliary support, while the inner spiral thread spool 12 uses cold extrusion to plastically flow the material on the inner wall of the circular tube 4, forming an internal thread. Throughout the entire processing, the centering ring seat 10 always maintains radial pressure on the circular tube 4 to prevent the tube wall from becoming unstable. The elastic follow-up support assembly allows the circular tube 4 to generate a small radial expansion during rolling, avoiding over-constraint. After processing is completed, the drive assembly stops and reverses to reset. The vertical plate 2 moves in the opposite direction, causing the outer spiral thread spool 9 and the inner spiral thread spool 12 to disengage from the round tube 4. The cylinder 7 drives the loading seat 5 and the lower pressure seat 6 to separate. The loading plate 11 moves longitudinally to push out the finished round tube 4, and at the same time sends the next round tube 4 to be processed into the work station, realizing the continuous automated production of symmetrical internal spiral threaded round tubes.

[0027] The results of the solution are as follows: The symmetrical inner and outer coordinating rolling of the outer spiral thread spool 9 and the inner spiral thread spool 12 ensures that the pipe wall of the round pipe 4 is subjected to uniform radial compressive stress, effectively suppressing local plastic deformation and overall collapse. The centering ring seat 10 utilizes the linkage of the fixed block 14, the movable block 15, the inner retraction spring 16, the outer support spring 13, the guide block 21, and the inner retraction slider 22 to achieve rapid adaptive centering and radial pre-tightening of the round pipe 4, eliminating uneven thread pitch caused by clamping eccentricity. The elastic follow-up support assembly provides adjustable flexible support for the end of the round pipe 4 through the cooperation of the semi-open sleeve 17, the compression spring 19, and the rotating screw 18, avoiding axial bending or vibration caused by rigid clamping and ensuring the consistency of the thread pitch diameter.

[0028] In summary, this invention addresses the problem that traditional two-axis rolling mills can only apply extrusion pressure to hollow tubes from two opposite directions, resulting in uneven radial stress on the tube wall, easy local plastic deformation or even overall collapse, and a serious decrease in roundness. By setting the outer spiral thread spool 9 and the inner spiral thread spool 12 in the same vertical plane, the two can rotate synchronously and feed axially under the control of the drive assembly, applying symmetrical rolling action to the inner and outer walls of the round tube 4 at the same time. Combined with the radial pressing structure formed by the outer support spring 13, the inner sliding block 22, the movable block 15 and the fixed block 14 inside the centering ring seat 10, it is ensured that the round tube 4 is always subjected to uniformly distributed radial pressure in the entire circumferential direction, avoiding stress concentration caused by single tangential extrusion, and improving the roundness and tube shape retention ability after internal thread processing. Specifically, by setting up the semi-open sleeve 17, compression spring 19 and rotating screw 18 in the elastic follow-up support assembly, a flexible and adjustable support port 20 is provided for the end of the round tube 4. At the same time, the automatic centering and rapid clamping of the round tube 4 is achieved by using the linkage between the bottom opening of the centering ring seat 10, the movable block 15 and the inner retraction spring 16, which suppresses the vibration and axial movement caused by the rotary feed during the processing, and ensures the uniformity of the thread pitch and the processing accuracy of the thread pitch diameter.

[0029] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. 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. A roll forming integrated device for symmetrical internal spiral threaded round tubes, comprising a vertical plate (2) and roll forming components and a triaxial opposing component symmetrically arranged between the vertical plates (2), characterized in that: The roll forming assembly includes an outer spiral thread disc (9) and an inner spiral thread disc (12) located in the middle of the inner side of the vertical plate (2) and in the same vertical plane. The axial movement and rotation of the outer spiral thread disc (9) and the inner spiral thread disc (12) together complete the thread roll forming of the round tube (4). The three-axis opposing assembly includes a centering ring seat (10) located on the inner side of the round tube (4) near the outer spiral spool (9). The centering ring seat (10) is a closed semi-ring structure with an open bottom. A fixing block (14) is installed at the upper middle part of the inner ring side of the centering ring seat (10). Both ends of the fixing block (14) are equipped with movable blocks (15) through an internal retraction spring (16). The inner ring seat (10) is longitudinally filled with an outer support spring (13), and a guide block (21) is installed at the inner bottom of the inner ring seat (10). Both ends of the outer support spring (13) are equipped with an inner sliding block (22) that slides with the guide block (21). The outer end of the inner sliding block (22) extends to the inner ring side of the inner ring seat (10) and is connected to the movable block (15).

2. The integrated rolling forming device for a symmetrical internally spiral threaded round tube according to claim 1, characterized in that, A base plate (1) is installed at the bottom of the two upright plates (2). The base plate (1) is horizontally aligned with the middle of the upright plates (2) and is equipped with a loading seat (5) and a pressing seat (6) that are arranged opposite to each other. A top plate (3) is installed between the upper ends of the two upright plates (2). A cylinder (7) for vertically driving the loading seat (5) and the pressing seat (6) is installed in the middle of the base plate (1) and the top plate (3).

3. The integrated rolling forming device for a symmetrical internally spiral threaded round tube according to claim 2, characterized in that, A feeding plate (11) is slidably mounted on both sides of the middle part of the upper surface of the substrate (1). The feeding plate (11) is provided with a groove for intermittent feeding of the round tube (4), and the feeding seat (5) and the lower pressure seat (6) are provided with a support hole that matches the round tube (4) at their close ends.

4. The integrated rolling forming device for a symmetrical internally spiral threaded round tube according to claim 1, characterized in that, The outer side of the inner spiral spool (12) is equipped with a rotating seat (8) connected to the vertical plate (2). The rotating seat (8) is provided with an elastic follow-up support assembly on the side near the round tube (4). The elastic follow-up support assembly includes a semi-open sleeve (17) provided inside the rotating seat (8). The semi-open sleeve (17) and the inner spiral spool (12) form a support port (20) for inserting and fixing the end of the round tube (4).

5. The integrated rolling forming device for a symmetrical internally spiral threaded round tube according to claim 4, characterized in that, The outer circular array of the semi-open sleeve (17) has compression springs (19), and the upper end of the compression springs (19) is threaded with a rotating screw (18) that is rotatably connected to the rotating seat (8).

6. The integrated rolling forming device for a symmetrical internally spiral threaded round tube according to claim 1, characterized in that, The bottom opening length of the central ring seat (10) is greater than the diameter of the round tube (4). When the round tube (4) squeezes the two movable blocks (15) to move upward, the inner spring (16) is compressed. When the round tube (4) contacts the fixed block (14), the inner spring (16) returns to its original position.

7. The integrated rolling forming device for a symmetrical internally spiral threaded round tube according to claim 6, characterized in that, When the round tube (4) is centered in the centering ring seat (10), the outer support spring (13) always applies a radial pressing action on the round tube (4) to the inner sliding block (22) and the movable block (15).

8. The integrated rolling forming device for a symmetrical internally spiral threaded round tube according to claim 3, characterized in that, The middle part of each upright plate (2) is equipped with a drive assembly, which is used to control the rotation axis movement of the outer spinning disc (9) and the inner spinning disc (12) respectively.

9. The integrated rolling forming device for a symmetrical internally spiral threaded round tube according to claim 3, characterized in that, The bottom of both the upright plate (2) and the feeding plate (11) is equipped with a slide rail assembly set on the upper side of the base plate (1) for applying the axial movement of the upright plate (2) and the longitudinal movement of the feeding plate (11).

10. A symmetrical internally threaded round tube, processed using the integrated roll forming apparatus as described in any one of claims 1-9, characterized in that, The round tube (4) is hollow and has inner and outer threaded parts on the inner and outer walls of both ends of the round tube (4) respectively, which cooperate with the inner spiral thread (12) and the outer spiral thread (9).

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