Machining method for bidirectional spinning thinning of variable-diameter metal pipe fitting

Abstract

The invention provides a machining method for bidirectional spinning thinning of a reducing metal pipe fitting, a spinning machine is used for spinning the metal pipe fitting, one end of the metal pipe fitting is a first end face, the other end of the metal pipe fitting is a second end face, the spinning machine comprises a core mold, a discharging ring, stop teeth and a spinning roller, the discharging ring is connected with the core mold, the stop teeth are arranged on the periphery of the discharging ring, and the spinning roller is arranged on the discharging ring. The machining method comprises the following steps that S1, a first end face is connected with a stop tooth, and a machining area of a core mold is sleeved with a metal pipe fitting through first-time feeding; s2, performing first spinning from the joint part of the metal pipe fitting by cutting for the first time, wherein a spinning object is an area from the joint part to the first end surface; s3, unloading is conducted; s4, after the direction of the metal pipe fitting is adjusted, secondary feeding is conducted, and the second end face is connected with the stop teeth; and S5, secondary cutting is conducted from the joint part for secondary spinning, and the spinning object is the area from the joint part to the second end face. And 1 / 2 part of the metal pipe fitting is spun and thinned, then the feeding direction is turned, and the other half part of the metal pipe fitting is joined and spun, so that the problem that a workpiece with the corresponding length cannot be machined due to the limitation of the machining range of a spinning machine or the insufficient length of a core mold is solved.

Description

Technical Field

[0001] The invention relates to the technical field of spinning of metal pipe fittings, and in particular to a bidirectional spinning and thinning processing method for a diameter-variable metal pipe fitting. Background Art

[0002] Spinning is a processing technology in which a flat plate or hollow blank is fixed on the core mold of a spinning machine. While the blank rotates with the spindle of the machine tool, a spinning wheel or a driving rod is used to pressurize the blank to cause local plastic deformation. It is widely used in important fields such as missile casings, rocket casings and engine casings. It is also further widely used in civilian products and machinery manufacturing with the upgrading and improvement of spinning equipment.

[0003] The thinning spinning of metal pipe fittings has important applications in the fields of rocket shells, metal gas cylinders and automobiles. Its main movement is mainly the rotation of the workpiece driven by the core mold. The plastic forming of the workpiece depends on the axial and radial feeding of the spinning wheel, and the rolling movement of the blank is completed. Among them, although the reverse rotation (the flow direction of the blank material is opposite to the movement direction of the spinning wheel) can make the length of the processed workpiece greater than the length of the core mold, due to the influence of the ultimate thinning rate of the tube blank itself, the longest length of the processed pipe fitting is roughly equal to the mold length / material single-pass thinning rate, especially when the processed metal pipe is segmented and the diameter is changed, the thinning rate of the thicker wall segment is slightly smaller, and the maximum processing length of the pipe fitting is smaller. When the length of the pipe fitting to be processed is slightly longer than this value, it is necessary to process a longer core mold until the processing range limit of the equipment is reached. In addition, when the length of the processed pipe fitting is too long and exceeds the length of the core mold too much, it is easy to cause local deformation of the cylinder due to the influence of gravity, which has a serious impact on the size and performance of the workpiece. Summary of the invention

[0004] In view of this, the present invention aims to propose a bidirectional spinning thinning processing method for variable diameter metal pipe fittings to solve the problem that the length of the metal pipe fittings after spinning thinning cannot exceed the length limit of the core mold or the processing range of the spinning machine during reverse spinning.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] A processing method for bidirectional spinning and thinning of a variable diameter metal pipe fitting, using a spinning machine to spin the metal pipe fitting, one end of the metal pipe fitting is a first end face and the other end is a second end face, the spinning machine includes a core mold, a discharge ring, a stop tooth and a spinning wheel, the discharge ring is connected to the core mold, and a stop tooth is arranged on the outer periphery of the discharge ring, and the processing method includes the following steps:

[0007] S1. The first end surface is connected to the stop tooth, and the first feeding makes the metal pipe sleeve disposed in the processing area of ​​the core mold;

[0008] S2. The first spinning is performed from the connection portion of the metal pipe, and the spinning object is the area from the connection portion to the first end surface;

[0009] S3. Unloading;

[0010] S4. After the direction of the metal pipe is turned, the second feeding is performed, and the second end face is connected to the stop tooth;

[0011] S5. Perform secondary spinning from the connecting portion, and the spinning object is the area from the connecting portion to the second end face.

[0012] Furthermore, in the step S1, the metal pipe is processed to form a first groove at the first end face thereof, and the first groove and the stop tooth cooperate with each other to connect the metal pipe and the spinning machine.

[0013] Furthermore, in step S2, the connecting portion is located at the center of the length direction of the metal pipe before the metal pipe is thinned by spinning.

[0014] Furthermore, in step S2, after the first spinning is completed, the metal pipe has a thin and long workpiece formed from the first end face to the connecting portion, and the connecting portion to the second end face has not been processed, so that the connecting portion has a variable diameter structure and forms a slope.

[0015] Furthermore, in step S3, after the first spinning is completed, the metal pipe is unloaded, the inside of the metal pipe is polished and cleaned, and lubricating oil is evenly applied to the inside of the second end surface.

[0016] Furthermore, in the step S4, the metal pipe is processed to form a second groove at the second end face, and the second groove and the stop tooth cooperate with each other to connect the metal pipe and the spinning machine.

[0017] Furthermore, in step S5, the pressing amount of the connecting portion is adjusted according to the slope of the slope generated during the processing of the area from the connecting portion to the first end surface and the actual thickness of the first end surface after the first spinning.

[0018] Furthermore, a supporting device is provided at one end of the core mold away from the stopping tooth, and the metal pipe is provided on the supporting device.

[0019] Furthermore, the supporting device includes a bracket and symmetrically arranged rollers, the metal pipe is arranged between the two rollers, and the metal pipe can rotate between the two rollers.

[0020] Compared with the prior art, the bidirectional spinning thinning processing method of a variable diameter metal pipe described in the present invention has the following advantages:

[0021] (1) The metal pipe is first spun and thinned by 1 / 2 part, and then the feeding direction is reversed to connect the other half of the blank for spinning, thereby avoiding the problem of being unable to process the corresponding length of the workpiece due to the limited processing range of the spinning machine or the insufficient length of the core mold;

[0022] (2) A first groove and a second groove are respectively provided at both ends of the metal pipe for connecting and cooperating with the stop teeth, so that the metal pipe is fixed on the spinning machine and rotates with the core mold;

[0023] (3) By adding a supporting device, it is possible to prevent the metal pipe from being deformed during the rotation process due to the influence of gravity when the excess part exceeds the core mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 This is a schematic structural diagram of processing a first groove on a first end surface according to the present invention;

[0026] Figure 2 for Figure 1 Left view of;

[0027] Figure 3 It is a structural schematic diagram of the core mold and the discharge ring of the spinning machine according to the present invention;

[0028] Figure 4 It is a schematic diagram of the structure when the first groove and the stop tooth of the present invention cooperate with each other;

[0029] Figure 5 A schematic diagram of a structure in which a rotary wheel is pressurized and arranged between the connecting portion and the first end surface;

[0030] Figure 6 Schematic diagram of completing the first spinning process;

[0031] Figure 7 This is a schematic diagram of secondary loading after reversing the direction of the metal pipe;

[0032] Figure 8 It is a schematic diagram of the structure when the second groove and the stop tooth of the present invention cooperate with each other;

[0033] Fig. 9 Schematic diagram of the metal pipe supporting the support device.

[0034] Description of reference numerals:

[0035] 1. Metal pipe fittings; 2. Support device; 3. Core mold; 4. Discharge ring; 5. Stop tooth; 6. Rotary wheel; 7. First end face; 8. Second end face; 9. First groove; 10. Second groove; 11. Connecting part; 12. Bracket; 13. Roller. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with specific embodiments. It should be noted that the data in the following experimental examples are obtained by the inventor through a large number of experiments. Due to space limitations, only a part of them is shown in the specification, and those of ordinary skill in the art can understand and implement the present invention under these data. These embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these changes or modifications also fall within the scope protected by the present application.

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0038] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0039] The present invention provides a bidirectional spinning thinning processing method for a variable diameter metal pipe fitting, which uses a spinning machine to spin a metal pipe fitting 1, such as Figures 1 to 3 As shown, the metal pipe 1 is a hollow structure, and one end is a first end face 7 and the other end is a second end face 8. The spinning machine includes a core mold 3, a discharge ring 4, a stop tooth 5 and a rotating wheel 6. The discharge ring 4 is connected to the core mold 3, and the outer periphery of the discharge ring 4 is provided with a stop tooth 5. The processing method includes the following steps:

[0040] S1. The first end surface 7 is connected to the stop tooth 5, and the first feeding makes the metal pipe 1 sleeved in the processing area of ​​the core mold 3;

[0041] Specifically, the metal pipe 1 is processed to form a first groove 9 at its first end face 7, and the first groove 9 cooperates with the stop tooth 5 to connect the metal pipe 1 to the spinning machine. The stop tooth 5 is distributed with a plurality of saw teeth, and the first groove 9 is embedded in the tooth groove formed by two adjacent saw teeth of the stop tooth 5 to achieve a tight connection.

[0042] like Figure 4 As shown, after lubricating oil is applied to the inside of the first end face 7, the first loading is performed, and the metal pipe 1 is sleeved in the processing area of ​​the core mold 3. At this time, the length of the metal pipe 1 is relatively short, and the core mold 3 extends out of the second end face 8.

[0043] S2. The first spinning is performed from the connecting portion 11 of the metal pipe 1, and the spinning object is the area from the connecting portion 11 to the first end surface 7;

[0044] Specifically, the connection portion 11 described in the present application is located at the center of the metal pipe 1 in the length direction before the metal pipe 1 is spun and thinned.

[0045] Combined with step S1, since the first processing in this application is to cut at the center of the metal pipe 1, the main forces acting when the first end face 7 and the stop tooth 5 are in contact are the annular friction force and the radial pressure, which cannot effectively push the metal pipe 1 to embed into the stop tooth 5, thereby jamming the metal pipe 1. Therefore, the cooperation between the first groove 9 and the stop tooth 5 is utilized to avoid the rotary wheel 6 cutting in the middle of the metal pipe 1 during the first processing, causing the metal pipe 1 to be unable to embed into the stop tooth 5 and unable to rotate with the core mold 3 for thinning processing.

[0046] When performing the first spinning, the number of passes is set according to the thickness and diameter change requirements of the metal pipe 1. Usually, 2 to 4 passes are required. Figure 5 As shown in the figure, during the processing, the roller 6 is pressurized and arranged between the connection part 11 and the first end face 7. The metal pipe 1 set in the processing area of ​​the core mold 3 rotates with the main axis of the machine tool, and is subjected to the feeding driving force of the roller 6 to produce local plastic deformation, which is used to achieve stretching and thinning. The first spinning direction is from the connection part 11 to the first end face 7. The metal pipe 1 after the first spinning is completed is as shown in FIG. Figure 6 As shown, a thin and long workpiece is formed from the first end face 7 to the connecting portion 11. The connecting portion 11 to the second end face 8 has not been processed yet, so that the connecting portion 11 has a reduced diameter structure and forms a slope.

[0047] In the prior art, the first cutting is performed at the end of the metal pipe 1 to ensure that the end face of the metal pipe 1 is embedded in the stop tooth 5 under the action of the axial thrust. Since the present application adopts the method of cutting at the center, the first groove 9 is firstly provided at the first end face 7 to ensure the tight connection between the first end face 7 and the stop tooth 5. As the processing progresses, the rotating wheel 6 moves, so that the metal pipe 1 is subjected to the axial thrust, ensuring that the metal pipe 1 and the stop tooth 5 will not loosen or fall off.

[0048] S3. Unloading;

[0049] After the first spinning is completed, the metal pipe 1 is unloaded, and the inside is polished and cleaned, and lubricating oil is evenly applied to the inside of the second end face 8. The internal polishing treatment can avoid the reduction of the inner diameter of the thinned pipe due to a large amount of pressure reduction or too fast feed speed during the reverse spinning process, and the second end face 8 is too close to the core mold 3 after turning around, which makes it difficult to load the material.

[0050] S4. After the direction of the metal pipe 1 is reversed, the second end face 8 is connected to the stop tooth 5;

[0051] Specifically, the metal pipe 1 is processed to form a second groove 10 at its second end face 8. The second groove 10 cooperates with the stop tooth 5 to connect the metal pipe 1 to the spinning machine. The stop tooth 5 is provided with a plurality of saw teeth, and the second groove 10 is embedded in the tooth groove formed by two adjacent saw teeth of the stop tooth 5 to achieve a tight connection. More specifically, in the present application, the order of the step of processing the second end face 8 to form the second groove 10 is not specifically limited. The second groove 10 can be formed while the first groove 9 is formed in step S1, or the second groove 10 can be formed after unloading in step S3.

[0052] like Figure 7 As shown, the direction of the metal pipe 1 is reversed for secondary loading. During secondary loading, the roller 6 clamps the second end face 8 to the area of ​​the connecting portion 11 and performs axial movement to assist loading, thereby avoiding loading difficulties caused by excessive fit and large friction between the inner wall of the metal pipe 1 after the initial thinning and the core mold 3. The roller 6 acts on the slope, and part of the force generated by the roller 6 is decomposed into axial thrust, which pushes the second end face 8 to embed into the stop tooth 5.

[0053] S5. Perform secondary spinning from the connecting portion 11 , where the spinning object is the area from the connecting portion 11 to the second end face 8 .

[0054] Specifically, the pressing amount of the connecting portion 11 is adjusted according to the slope of the slope generated during the processing of the area from the connecting portion 11 to the first end face 7 and the actual thickness of the first end face 7 after the first spinning, so as to avoid improper connection and ensure that the metal pipe 1 finally obtained has a uniform pipe diameter, thus solving the problem of different sizes on both sides of the connecting portion 11. Figure 8 As shown, the direction of the secondary spinning is from the connecting portion 11 to the second end face 8. The area from the connecting portion 11 to the second end face 8 forms a thin and long workpiece.

[0055] After the secondary spinning is completed, the metal pipe 1 forms a workpiece with a thinner overall wall thickness, and becomes longer and thinner after spinning thinning.

[0056] During the connection process of the secondary spinning, as the spinning process continues, the length of the metal pipe 1 exceeds the core mold 3 and continues to lengthen. In order to prevent the metal pipe 1 from deforming, Fig. 9As shown, a support device 2 is provided at one end of the core mold 3 away from the stop tooth 5, and the metal pipe 1 is provided on the support device 2, and the support device 2 is used to provide support for the metal pipe 1. The support device 2 includes a bracket 12 and symmetrically arranged rollers 13. The metal pipe 1 is provided between two rollers 13, and the rollers 13 are used to provide support for the metal pipe 1. During the rotation of the metal pipe 1 by spinning and thinning, the metal pipe 1 can rotate between the two rollers 13, and the rollers 13 will not affect the rotation of the metal pipe 1. According to the height and extension rate of the metal pipe 1 during the processing, the height of the support device 2 and the angle of the roller 13 are adjusted, so that the part exceeding the core mold 3 during the processing can be rotated and extended on the support device 2, so as to avoid serious deformation of the metal pipe 1 due to the influence of gravity.

[0057] Specifically, during the secondary spinning, the second end face 8 is still connected to the stop tooth 5, and the first end face 7 exceeds the core mold 3 and loses support. Therefore, the area from the connecting part 11 to the first end face 7 is arranged on the supporting device 2 to avoid deformation of the metal pipe 1 when it becomes thinner and longer during the rotating processing.

[0058] When the spinning machine is working, the movement direction of the rotating wheel 6 is toward the direction of the stop tooth 5, and the extension direction of the metal pipe 1 is away from the stop tooth 5. In the process of reverse spinning thinning of the pipe fittings of the present invention, if the length of the processed metal pipe fitting 1 exceeds the length limit of the core mold 3, firstly perform spinning thinning of 1 / 2 part, then reverse the feeding direction, and connect the spinning of the other half of the blank, thereby avoiding the problem of being unable to process the corresponding length of the workpiece due to the limited processing range of the spinning machine or the insufficient length of the core mold 3. At the same time, as the length of the metal pipe fitting 1 is continuously extended with different degrees of wall thickness thinning during the reverse spinning process, when it exceeds the core mold 3 too long, the part exceeding the core mold 3 will be deformed during the spinning process due to the influence of gravity. This problem is avoided by adding a support device 2. By using a processing method of bidirectional spinning thinning of a variable diameter metal pipe fitting of the present invention, a variable diameter and thinned metal pipe fitting 1 with a processing length up to 1.5 to 2 times the processing limit of the core mold 3 or the spinning machine can be obtained. It not only breaks through the limitation of the processing range of the spinning machine and the length of the core mold 3 and effectively utilizes the length of the core mold 3, but also avoids the deformation problem caused by the excessive length of the metal pipe 1, thereby meeting the reverse spinning processing requirements of metal pipes 1 of different specifications within a larger length range.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for processing a variable diameter metal pipe by bidirectional spinning and thinning, wherein a spinning machine is used to spin a metal pipe (1), wherein one end of the metal pipe (1) is a first end face (7) and the other end is a second end face (8), wherein the spinning machine comprises a core mold (3), a discharge ring (4), a stop tooth (5) and a rotating wheel (6), wherein the discharge ring (4) is connected to the core mold (3), and a stop tooth (5) is arranged on the outer periphery of the discharge ring (4), and wherein: The processing method comprises the following steps: S1. The first end surface (7) is connected to the stop tooth (5), and the metal pipe (1) is sleeved in the processing area of ​​the core mold (3) for the first time; S2. The first spinning is performed from the connecting portion (11) of the metal pipe (1), and the spinning object is the area from the connecting portion (11) to the first end surface (7); S3. Unloading; S4. After the direction of the metal pipe (1) is reversed, the second end surface (8) is connected to the stop tooth (5); S5. Perform secondary spinning from the connecting portion (11), wherein the spinning object is the area from the connecting portion (11) to the second end face (8).

2. The method for bidirectional spinning thinning of a variable diameter metal pipe according to claim 1, characterized in that: In the step S1, the metal pipe (1) is processed to form a first groove (9) at its first end face (7), and the first groove (9) and the stop tooth (5) cooperate with each other to connect the metal pipe (1) and the spinning machine.

3. The method for bidirectional spinning thinning of a variable diameter metal pipe according to claim 1, characterized in that: In the step S2, the connecting portion (11) is located at the center of the metal pipe (1) in the length direction before the metal pipe (1) is thinned by spinning.

4. The method for bidirectional spinning thinning of a variable diameter metal pipe according to claim 1, characterized in that: In step S2, after the first spinning is completed, the metal pipe (1) forms a thin and long workpiece in the area from the first end face (7) to the connecting portion (11), and the area from the connecting portion (11) to the second end face (8) has not yet been processed, so that the connecting portion (11) has a variable diameter structure and forms a slope.

5. The method for bidirectional spinning and thinning of a variable diameter metal pipe according to claim 1, characterized in that: In the step S3, after the first spinning is completed, the metal pipe (1) is unloaded, the inside of the metal pipe (1) is polished and cleaned, and lubricating oil is evenly applied to the inside of the second end surface (8).

6. The method for bidirectional spinning and thinning of a variable diameter metal pipe according to claim 1, characterized in that: In the step S4, the metal pipe (1) is processed to form a second groove (10) at the second end surface (8), and the second groove (10) and the stop tooth (5) cooperate with each other to connect the metal pipe (1) and the spinning machine.

7. The method for bidirectional spinning thinning of a variable diameter metal pipe according to claim 1, characterized in that: In step S5, the pressing amount of the connecting portion (11) is adjusted according to the slope of the slope generated during the processing of the area from the connecting portion (11) to the first end surface (7) and the actual thickness of the first end surface (7) after the first spinning.

8. The method for bidirectional spinning and thinning of a variable diameter metal pipe according to claim 1, characterized in that: A support device (2) is provided at one end of the core mold (3) away from the stop tooth (5), and the metal pipe (1) is provided on the support device (2).

9. The method for bidirectional spinning and thinning of a variable diameter metal pipe according to claim 8, characterized in that: The supporting device (2) comprises a bracket (12) and symmetrically arranged rollers (13); the metal pipe (1) is arranged between the two rollers (13); and the metal pipe (1) can rotate between the two rollers (13).

Images