A thin-walled metal ball and a method for preparing the same

Abstract

The present invention provides a thin-walled metal ball and a preparation method thereof, which solves the technical problems of the existing method that the process is long and the weld is easy to crack. The thin-walled metal ball is provided with and only has a pair of mounting through holes or mounting protrusions arranged opposite to each other on the ball wall along the central axis of the thin-walled metal ball. The preparation method of the thin-walled metal ball comprises the steps of: placing a thin-walled metal round tube between an upper die and a lower die of a forming device; along the axial direction of the thin-walled metal round tube, the upper die and the lower die are molded together, and the openings at both ends of the thin-walled metal round tube are simultaneously shrunken and extruded to form, and finally a thin-walled metal ball is formed in a spherical cavity formed after the upper die and the lower die are molded together; the forming device is provided with an upper die and a lower die, the upper die is provided with a first hemispherical cavity, and the lower die is provided with a second hemispherical cavity, and the first hemispherical cavity and the second hemispherical cavity are arranged opposite to each other at intervals; when the upper die and the lower die are molded together, the first hemispherical cavity and the second hemispherical cavity form a closed spherical cavity. It can be widely used in the technical field of thin-walled metal ball manufacturing.

Description

Technical Field

[0001] The present application relates to the technical field of thin-walled metal ball manufacturing, and in particular to a thin-walled metal ball and a preparation method thereof. Background Art

[0002] Thin-walled metal balls are characterized by light weight, large specific surface area, and high specific mechanical properties. They are widely used in aerospace, medicine, atomic energy, machinery, construction, electrochemistry and other fields. The main manufacturing methods of thin-walled metal balls are hydraulic bulging forming. The main processes of hydraulic bulging forming are: cutting, bending, assembly welding, liquid filling bulging, etc. The method used to prepare thin-walled metal balls has the advantages of high material utilization and is convenient for on-site assembly and welding. However, the hydraulic bulging forming method has the technical problems of long time and process required, and the weld is prone to cracking during liquid filling bulging. This technical problem needs to be solved urgently. Summary of the invention

[0003] The purpose of the present invention is to solve the deficiencies of the above-mentioned technology, provide a thin-walled metal ball and a preparation method thereof, reduce the preparation steps of the thin-walled metal ball, and improve the quality of the finished product.

[0004] To this end, the present invention provides a thin-walled metal ball. Along the central axis of the thin-walled metal ball, there is only one pair of mounting through holes or mounting protrusions arranged opposite to each other on the ball wall of the thin-walled metal ball.

[0005] The present invention also provides a method for preparing a thin-walled metal ball, comprising the steps of: placing a thin-walled metal round tube between an upper die and a lower die of a forming device; along the axial direction of the thin-walled metal cylinder, the upper die and the lower die simultaneously shrink the openings at both ends of the thin-walled metal cylinder to form a thin-walled metal ball in a spherical cavity formed by closing the upper die and the lower die, and obtaining the thin-walled metal ball after opening the die;

[0006] The forming device is provided with an upper die and a lower die. The upper die is provided with a first hemispherical cavity, and the lower die is provided with a second hemispherical cavity. The first hemispherical cavity and the second hemispherical cavity are arranged opposite to each other with a gap. When the upper die and the lower die are closed, the first hemispherical cavity and the second hemispherical cavity form a closed spherical cavity.

[0007] Preferably, the forming device is also provided with a cylindrical support body, which is sleeve-connected to the lower mold, and the outer wall of the lower mold is in close contact with the inner wall of the cylindrical support body, the inner wall of the cylindrical support body tightly surrounds the circumferential edge of the second hemispherical cavity, and the cylindrical support body is slidably connected to the lower mold up and down; when the thin-walled metal circular tube is placed in the cylindrical support body between the upper mold and the lower mold of the forming device, the outer wall of the thin-walled metal circular tube is matched with the inner wall of the cylindrical support body with a small gap, and the outer side of the bottom of the thin-walled metal circular tube is located at the circumferential edge of the second hemispherical cavity.

[0008] Preferably, the plasticity of the thin-walled metal round tube gradually increases from the middle to both ends.

[0009] Preferably, the tube openings at both ends of the thin-walled metal circular tube are provided with outer chamfers respectively matching the contact surfaces of the first hemispherical cavity and the second hemispherical cavity.

[0010] Preferably, before placing the thin-walled metal round tube between the upper die and the lower die of the forming device, lubricant is applied to the outer wall of the thin-walled metal round tube, the cavity wall of the first hemispherical cavity, and the cavity wall of the second hemispherical cavity respectively.

[0011] Preferably, a residual material receiving groove is provided at the bottom of the first hemispherical cavity and the second hemispherical cavity.

[0012] Preferably, the lower die remains stationary, and the upper die is driven downward to move at a speed of 10-50 mm / min, thereby completing the extrusion forming of the thin-walled metal round tube.

[0013] Preferably, the elastic member is a spring or a spring sheet.

[0014] Preferably, a first step protrusion is provided on the outer periphery of the cylindrical support body, the first step protrusion is arranged in the annular groove, and a second step protrusion is provided on the outer ring wall of the annular groove, and the second step protrusion is used to prevent the first step protrusion from escaping from the annular groove.

[0015] Preferably, the forming device is further provided with an upper template, a lower template and an elastic member; the upper template is provided with an upper mold and an annular gasket, and the lower template is provided with a lower mold; the lower template is provided with an installation blind hole, the lower mold is arranged in the installation blind hole, and the side wall of the lower mold and the side wall of the installation blind hole form an annular groove with an upper opening; the upper end of the cylindrical support body exposes the circumferential edge of the second hemispherical cavity; the cylindrical support body is connected to the annular groove through the elastic member; the annular gasket is arranged to face the cylindrical support body up and down; the upper mold is arranged in the annular gasket;

[0016] When the upper template and the lower template are closed, the first hemispherical cavity and the second hemispherical cavity form a closed spherical cavity, and the cylindrical support body is completely pressed downward into the annular groove by the upper template; when the upper template and the lower template are opened, the first hemispherical cavity and the second hemispherical cavity are separated from each other, and the cylindrical support body is separated from the upper template, and under the action of the elastic force of the elastic part, one end of the cylindrical support body is exposed from the circumferential edge of the second hemispherical cavity.

[0017] Preferably, the forming equipment is further provided with a material ejecting device, the material ejecting device is provided with a material ejecting rod and a driving device, the material ejecting rod is a lead screw, and the driving device is a servo motor; the lower end of the lead screw is coaxially connected to the power output end of the servo motor; the lead screw is connected to the lower die through a nut adapted thereto; under the power output of the servo motor, the lead screw causes the lower die to rise or fall along the inner wall of the cylindrical support body;

[0018] The lower template is provided with a first lower template and a second lower template, and the first lower template and the second lower template are stacked and connected from top to bottom; the first lower template is provided with a through hole, and the side wall of the through hole, the side wall of the lower mold and the upper surface of the second lower template form an annular groove with an upper opening; a spring mounting hole and a lower mold limiting hole are respectively provided on the upper surface of the second lower template, and the spring mounting hole is arranged at the bottom of the annular groove; the lower mold limiting hole is arranged directly below the cylindrical support body, and the lower mold is slidably connected in the lower mold limiting hole;

[0019] A drive device mounting hole is opened on the lower surface of the second lower mold plate, and the drive device mounting hole is connected with the lower mold limit hole through a connecting channel; the servo motor is installed in the drive device mounting hole, and the lead screw passes through the connecting channel and is connected to the lower mold through a nut.

[0020] The beneficial effects of the present invention are as follows: the present invention provides a thin-walled metal ball and a preparation method thereof, and adopts a metal pipe upper and lower end simultaneous shrinking forming method to manufacture the thin-walled metal ball. Compared with the prior art, the machining and welding steps in the traditional thin-walled metal ball processing are omitted, and the technical problem that the weld is prone to cracking during liquid filling and bulging is fundamentally avoided, thereby improving product quality, significantly improving production and processing efficiency, and having a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 A schematic structural diagram of a cross-sectional view of a thin-walled metal ball of a first structure;

[0023] Figure 2 is a schematic structural diagram of a cross-sectional view of a thin-walled metal ball of a second structure;

[0024] Figure 3 A schematic structural diagram of a cross-sectional view of a thin-walled metal ball of a third structure;

[0025] Figure 4 It is a schematic diagram of the structure of a thin-walled metal circular tube;

[0026] Figure 5 It is a structural schematic diagram of a cross-sectional view of a thin-walled metal circular tube.

[0027] Figure 6 is a schematic structural diagram of a forming device;

[0028] Figure 7 for Figure 6The structural diagram of the AA perspective is shown;

[0029] Figure 8 for Figure 6 A schematic structural diagram of a top view of the lower template shown;

[0030] Fig. 9 for Figure 6 A schematic diagram of the structure of a partial cross-sectional view with a metal tube installed as shown;

[0031] Fig.10 It is a structural schematic diagram when the upper mold plate and the lower mold plate are molded together;

[0032] Fig.11 It is a structural schematic diagram of the upper and lower templates returning to their original state after being molded together;

[0033] Fig.12 A schematic diagram of the structure of the present invention in which a thin-walled metal ball is ejected;

[0034] Fig.13 for Fig. 9 A schematic structural diagram of the enlarged view of part A shown.

[0035] Markings in the figure: 1. upper template, 2. lower template, 3. cylindrical support body, 4. spring, 5. upper mold, 6. lower mold, 7. first hemispherical cavity, 8. second hemispherical cavity, 9. annular groove, 10. spherical cavity, 11. residual material accommodating groove, 12. annular gasket, 13. first step protrusion, 14. second step protrusion, 15. screw, 16. servo motor, 17. nut, 18. mounting through hole, 19. spring mounting hole, 20. lower mold limiting hole, 21. first lower template, 22. second lower template, 23. drive device mounting hole, 24. mounting protrusion, 25. thin-walled metal round tube, 26. thin-walled metal ball, 27. connecting channel, 28. outer chamfer, 71. circumferential edge of the first hemispherical cavity 7, 81. circumferential edge of the second hemispherical cavity 8. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are preferred specific implementation methods, which are only used to explain this application and are not used to limit this application.

[0037] Unless otherwise specified, the methods used in the present invention are all conventional methods; the raw materials and devices used are all conventional commercially available products unless otherwise specified.

[0038] Depend on Figure 1-Figure 3 As shown, the present invention provides three thin-walled metal balls, wherein:

[0039] The structure of the first thin-walled metal ball is as follows: along the central axis of the thin-walled metal ball 26, there is only one pair of mounting through holes 18 arranged opposite to each other on the ball wall of the thin-walled metal ball 26, such as Figure 1 shown.

[0040] The second thin-walled metal ball has a structure as follows: along the central axis of the thin-walled metal ball 26, there is provided on the ball wall of the thin-walled metal ball 26 a pair of mounting protrusions 24 arranged opposite to each other, such as Figure 2 shown.

[0041] The third thin-walled metal ball structure, that is, the thin-walled metal ball 26 described in the prior art, is as follows: Figure 3 shown.

[0042] The thin-walled metal balls of the first two structures are used to connect the thin-walled metal balls with external devices by providing mounting through holes 18 or mounting protrusions 24. For example, bolts are passed through the bracket and then extended to be threadedly connected with the mounting through holes 18; or a pair of vertically opposite grooves are provided on the inner side of the C-shaped bracket, and the two mounting protrusions 24 of the thin-walled metal ball 26 are respectively adapted and clamped in the above grooves to complete the installation of the thin-walled metal ball.

[0043] For the thin-walled metal balls of the first two structures, the mounting through holes 18 and the mounting protrusions 24 are located at specific positions of the thin-walled metal ball 26, that is, there is only one pair of mounting through holes 18 or mounting protrusions 24, which are arranged along the central axis of the thin-walled metal ball 26 and directly opposite the ball wall of the thin-walled metal ball 26.

[0044] Depend on Figure 6 , Figure 7 , Fig. 9 , Fig.13 As shown, the present invention provides a forming device for preparing the above-mentioned thin-walled metal ball 26, the forming device is provided with an upper template 1, a lower template 2, a cylindrical support body 3 and an elastic member; the upper template 1 is provided with an upper mold 5, and the lower template 2 is provided with a lower mold 6; the upper mold 5 is provided with a first hemispherical cavity 7 opening downward, and the lower mold 6 is provided with a second hemispherical cavity 8 opening upward, and the first hemispherical cavity 7 and the second hemispherical cavity 8 are provided in a vertically opposite and adaptive arrangement; the lower template 2 is provided with a mounting blind hole, and the lower mold 6 is provided with a mounting blind hole. The cylindrical support body 3 is in the blind hole, and the side wall of the lower mold 6 and the side wall of the installation blind hole form an annular groove 9 with an upper opening; the upper end of the cylindrical support body 3 exposes the circumferential edge 81 of the second hemispherical cavity 8, the lower end of the cylindrical support body 3 is sleeved and connected with the lower mold 6, and the outer side wall of the lower mold 6 is close to the inner wall of the cylindrical support body 3, the inner wall of the cylindrical support body 3 tightly surrounds the circumferential edge 81 of the second hemispherical cavity 8, and the cylindrical support body 3 is connected to the lower mold 6 by sliding up and down; the cylindrical support body 3 is connected to the annular groove 9 through an elastic member; Fig.10As shown, when the upper mold plate 1 and the lower mold plate 2 are molded together, the first hemispherical cavity 7 and the second hemispherical cavity 8 form a closed spherical cavity 10, and the cylindrical support body 3 is completely pressed downward into the annular groove 9 by the upper mold plate 1; Fig. 9 , Fig.11 As shown, when the upper template 1 and the lower template 2 are opened, the first hemispherical cavity 7 and the second hemispherical cavity 8 are separated up and down, and the cylindrical support body 3 and the upper template 1 are separated from each other. Under the action of the elastic force of the elastic member, one end of the cylindrical support body 3 exposes the circumferential edge 81 of the second hemispherical cavity 8.

[0045] Before using the present invention, the upper surface of the upper template 1 is fixed on the upper anvil of the press, and the lower surface of the lower template 2 is installed on the lower anvil of the press, so that the first hemispherical cavity 7 and the second hemispherical cavity 8 are arranged vertically opposite to each other and spaced apart, and the cylindrical support body 3 and the upper template 1 are separated from each other, and the press is used to drive the upper template 1 to move up and down to complete the preparation work. Fig. 9 As shown, the upper template 1 and the lower template 2 are in an open mold state, and the thin-walled metal circular tube 25 is placed in the cylindrical support body 3. The outer wall of the thin-walled metal circular tube 25 and the inner wall of the cylindrical support body 3 are matched with a small gap to ensure that the cylindrical support body 3 continues to provide radial support force for the metal pipe 25 during deformation. At this time, the outer side of the bottom of the thin-walled metal circular tube 25 is located at the circumferential edge 81 of the second hemispherical cavity 8; at this time, the center lines of the first hemispherical cavity 7, the second hemispherical cavity 8, the cylindrical support body 3, and the thin-walled metal circular tube 25 coincide, and the upper end surface of the thin-walled metal circular tube 25 is preferably flush with the upper surface of the cylindrical support body 3. Then, the press is started, and the upper mold plate 1 moves downward, so that the upper mold plate 1 and the lower mold plate 2 are molded together, and the cylindrical support body 3 is slowly pressed downward into the annular groove 9 by the upper mold plate 1. During this process, the circumferential edge 71 of the first hemispherical cavity 7 contacts the outer side of the top of the thin-walled metal circular tube 25, and the press drives the upper mold plate 1 to continue to move downward, forcing the thin-walled metal circular tube 25 to undergo plastic deformation on both the upper and lower sides under the action of pressure. The cylindrical support body 3 provides radial support force for the thin-walled metal circular tube 25. During the downward movement of the upper mold plate 1, the upper mold 5 and the lower mold 6 The pressure perpendicular to the hemispherical cavity wall is provided respectively, and the radial support force is provided by the cylindrical support body 3. Under the guidance of the hemispherical cavity walls of the first hemispherical cavity 7 and the second hemispherical cavity 8, tangential stress is applied to the upper and lower ends of the thin-walled metal circular tube 25 respectively. The upper and lower ends of the thin-walled metal circular tube 25 slide along the direction of the hemispherical cavity wall, so that the upper and lower ends of the thin-walled metal circular tube 25 gradually shrink. During the whole process of mold closing, the center lines of the first hemispherical cavity 7, the second hemispherical cavity 8, the cylindrical support body 3, and the thin-walled metal circular tube 25 are always in a coincident state. Fig.10As shown, when the upper mold plate 1 and the lower mold plate 2 are molded together, the first hemispherical cavity 7 and the second hemispherical cavity 8 form a closed spherical cavity 10, and the cylindrical support body 3 is completely pressed downward into the annular groove 9 by the upper mold plate 1, and the upper and lower ends of the thin-walled metal round tube 25 finally fit at the bottom of their respective hemispherical cavities to obtain a thin-walled metal ball 26. As a preferred embodiment, Fig.13 As shown, the upper mold plate 1 is also equipped with an annular gasket 12, which is arranged vertically opposite to the cylindrical support body 3; the upper mold 5 is arranged in the annular gasket 12. During the mold closing process, the annular gasket 12 is in direct contact with the cylindrical support body 3 and is easily worn. The annular gasket 12 is specially designed and can be made of wear-resistant material to extend its service life and facilitate replacement.

[0046] As a preferred embodiment of the present invention, Fig. 9 As shown, the elastic member is a spring 4 or a spring sheet, which applies elastic force to the supporting cylindrical support body 3 in the annular groove 9.

[0047] As a preferred embodiment of the present invention, Fig.13 As shown, a first step protrusion 13 is provided on the outer periphery of the cylindrical support body 3, and the first step protrusion 13 is arranged in the annular groove 9. A second step protrusion 14 is provided on the outer ring wall of the annular groove 9, and the second step protrusion 14 is used to prevent the first step protrusion 13 from escaping from the annular groove 9.

[0048] As a preferred embodiment of the present invention, Fig.11 , Fig.12 As shown, the forming equipment is also provided with a material ejection device, which is provided with a material ejection rod and a driving device, one end of the material ejection rod is connected to the power output end of the driving device, and the other end of the material ejection rod is connected to the lower mold 6; under the power output of the driving device, the material ejection rod causes the lower mold 6 to rise or fall along the inner wall of the cylindrical support body 3, wherein the lower mold 6 rises along the inner wall of the cylindrical support body 3, lifts the thin-walled metal ball 26 out of the cylindrical support body 3, and after taking out the thin-walled metal ball 26, the lower mold 6 falls along the inner wall of the cylindrical support body 3 and returns to its original position. As a further preferred embodiment, the material ejection rod is a lead screw 15, the driving device is a servo motor 16, the lower end of the lead screw 15 is coaxially connected to the power output end of the servo motor 16; the lead screw 15 is connected to the lower mold 6 through a nut 17 adapted thereto; under the power output of the servo motor 16, the lead screw 15 causes the lower mold 6 to rise or fall along the inner wall of the cylindrical support body 3.

[0049] As a more preferred embodiment, Figure 6-Figure 9As shown, the lower template 2 is provided with a first lower template 21 and a second lower template 22, and the first lower template 21 and the second lower template 22 are stacked and connected from top to bottom; the first lower template 21 is provided with a through hole, and the side wall of the through hole, the side wall of the lower mold 6 and the upper surface of the second lower template 22 form an annular groove 9 with an upper opening; the upper surface of the second lower template 22 is provided with a spring mounting hole 19 and a lower mold limiting hole 20, respectively, and the spring mounting hole 19 is arranged at the bottom of the annular groove 9; the lower mold limiting hole 20 is arranged just below the cylindrical support body 3, and the lower mold 6 is slidably connected in the lower mold limiting hole 20. As a further more preferred embodiment, the lower surface of the second lower template 22 is provided with a drive device mounting hole 23, and the drive device mounting hole 23 is connected to the lower mold limiting hole 20 through a connecting channel 27; the servo motor 16 is installed in the drive device mounting hole 23, and the lead screw 15 passes through the connecting channel 27 and is connected to the lower mold 6 through a nut 17.

[0050] To summarize, the present invention provides a method for preparing a thin-walled metal ball, comprising the steps of: placing a thin-walled metal circular tube 25 between an upper die 5 and a lower die 6 of a forming device; along the axial direction of the thin-walled metal circular tube 25, the upper die 5 and the lower die 6 simultaneously shrink and extrude the openings at both ends of the thin-walled metal circular tube 25, and finally forming a thin-walled metal ball 26 in a spherical cavity 10 formed after the upper die 5 and the lower die 6 are closed, and the thin-walled metal ball 26 is obtained after the mold is opened.

[0051] The forming device is provided with an upper mold 5 and a lower mold 6. The upper mold 5 is provided with a first hemispherical cavity 7, and the lower mold 6 is provided with a second hemispherical cavity 8. The first hemispherical cavity 7 and the second hemispherical cavity 8 are arranged opposite to each other with a gap. When the upper mold 5 and the lower mold 6 are closed, the first hemispherical cavity 7 and the second hemispherical cavity 8 form a closed spherical cavity.

[0052] During the extrusion forming process in which the two ends of the thin-walled metal circular tube 25 are opened and shrunken at the same time, in order to avoid instability of the straight cylindrical part of the thin-walled metal circular tube 25, the forming device is also provided with a cylindrical support body 3, and the cylindrical support body 3 is sleeved and connected to the lower mold 6, and the outer wall of the lower mold 6 is tightly attached to the inner wall of the cylindrical support body 3, and the inner wall of the cylindrical support body 3 tightly surrounds the circumferential edge 81 of the second hemispherical cavity 8, and the cylindrical support body 3 is connected to the lower mold 6 by sliding up and down; when the thin-walled metal circular tube 25 is placed in the cylindrical support body 3 located between the upper mold 5 and the lower mold 6 of the forming device, the outer wall of the thin-walled metal circular tube 25 is matched with a small gap between the inner wall of the cylindrical support body 3, and the outer side of the bottom of the thin-walled metal circular tube 25 is located at the circumferential edge 81 of the second hemispherical cavity 8.

[0053] The material of the upper die 5 and the lower die 6 is preferably steel Cr12MoV, and both are quenched to extend the service life.

[0054] The thin-walled metal circular tube 25 is preferably heat-treated so that its plasticity gradually increases from the middle to both ends; preferably, the plasticity is symmetrically distributed from the middle to both ends. A device with a controllable temperature range is used to perform heat treatment at different temperatures on different parts of the thin-walled metal circular tube, so as to obtain the characteristic of gradually increasing plasticity from the middle to both sides, such as a gradient heat treatment method. During the closing process of the upper mold 5 and the lower mold 6, the thin-walled metal circular tube 25 is forced to undergo plastic deformation at both ends at the same time under the action of pressure, and the middle part remains in its original state without deformation; under the guidance of the hemispherical cavity walls of the first hemispherical cavity 7 and the second hemispherical cavity 8, the upper and lower ends of the thin-walled metal circular tube 25 slide along the direction of the hemispherical cavity walls, so that the ports at the upper and lower ends of the thin-walled metal circular tube 25 gradually shrink, and the deformation sequence of the thin-walled metal circular tube 25 is from its two ends to the middle at the same time.

[0055] The material of the thin-walled metal round tube 25 is usually steel, which has a wide range of applications, good plasticity after heat treatment and is easy to form, and has low material cost. The thin-walled metal round tube 25 can also be made of materials with good plasticity such as aluminum and copper.

[0056] The tube openings at both ends of the thin-walled metal round tube 25 are preferably provided with outer chamfers 28 respectively matching the contact surfaces of the first hemispherical cavity 7 and the second hemispherical cavity 8. When the upper mold 5 and the lower mold 6 begin to close the mold, the outer chamfers 28 are provided. On the one hand, it is convenient for the outer sides of the upper and lower ends of the thin-walled metal round tube 25 to fit with the circumferential edges 71 of the first hemispherical cavity 7 and the circumferential edges 81 of the second hemispherical cavity 8 respectively; on the other hand, it greatly reduces the initial resistance of the upper and lower ends of the thin-walled metal round tube 25 when they start to slide along the direction of the hemispherical cavity wall, breaks the static inertia, and avoids the thin-walled metal round tube 25 from becoming unstable and wrinkled.

[0057] Before placing the thin-walled metal round tube 25 between the upper die 5 and the lower die 6 of the forming device, it is best to apply lubricant to the outer wall of the thin-walled metal round tube 25, the cavity wall of the first hemispherical cavity 7, and the cavity wall of the second hemispherical cavity 8 respectively; in actual production, "phosphating (fluorinated siliconization)-saponification" treatment and the use of lubricating oil (grease) with added micron-grade graphite and molybdenum disulfide are usually used to perform special surface treatment and lubrication treatment on the blank to ensure good lubrication performance during forming and improve the surface quality of the parts. Among them, the lubricant at the circumferential edge 71 of the first hemispherical cavity 7 and the circumferential edge 81 of the second hemispherical cavity 8 can greatly reduce the initial friction resistance of the upper and lower ends of the thin-walled metal tube 25 sliding along the direction of the hemispherical cavity wall when the upper mold 5 and the lower mold 6 start to close the mold, break the static inertia, and avoid the middle of the thin-walled metal tube 25 from being unstable; the lubricant applied to the outer wall of the thin-walled metal tube 25, the cavity wall of the first hemispherical cavity 7, and the cavity wall of the second hemispherical cavity 8 further reduces the sliding friction resistance of the outer wall of the thin-walled metal tube 25 along the direction of the hemispherical cavity wall during the closing process, and avoids the middle of the thin-walled metal tube 25 from being unstable. In addition, polishing the cavity wall of the first hemispherical cavity 7 and the cavity wall of the second hemispherical cavity 8 is also one of the methods to reduce the sliding friction resistance of the outer wall of the thin-walled metal tube 25 along the direction of the hemispherical cavity wall.

[0058] Depend on Fig.13 As shown, the first hemispherical cavity 7 and the second hemispherical cavity 8 are preferably provided with a residual material receiving groove 11 at the bottom. After the upper and lower ends of the thin-walled metal round tube 25 are attached to the bottom of the respective hemispherical cavities, the residual material can flow into the residual material receiving groove 11 to obtain a thin-walled metal ball semi-finished product, and then the residual material part of the thin-walled metal ball semi-finished product is polished and ground to obtain a Figure 3 The thin-walled metal sphere shown.

[0059] The lower die 6 remains stationary, and the upper die 1 is driven downward to move at a speed of preferably 10-50 mm / min, thereby completing the bidirectional shrinking forming of the thin-walled metal round tube 25 .

[0060] By using any of the above-mentioned forming equipment and forming method, a Figure 1 , Figure 2 The spherical wall shown is provided with and only with a pair of mounting through holes 18 or mounting protrusions 24 arranged opposite to each other, and the preparation process is completed in one step. When the upper mold 5 and the lower mold 6 are molded together, the first hemispherical cavity 7 and the second hemispherical cavity 8 form a closed spherical cavity 10, and the cylindrical support body 3 is completely pressed downward into the annular groove 9 by the upper mold plate 1. If the upper and lower ends of the thin-walled metal round tube 25 are not in contact with the bottom of their respective hemispherical cavities at this time, the following will be obtained: Figure 1The thin-walled metal ball 26 shown is provided with and only with a pair of mounting through holes 18 arranged opposite to each other; if the upper and lower ends of the thin-walled metal round tube 25 fit at the bottom of their respective hemispherical cavities, and the excess material just fills the excess material receiving groove 11, the result will be as follows Figure 2 The illustrated embodiment is provided with one and only one pair of thin-walled metal balls 26 with mounting protrusions 24 arranged opposite to each other.

[0061] Without considering the influence of the thickening caused by the plastic deformation of the material on the size, the size of the thin-walled metal tube 25 can be estimated: assuming that the neutral layer diameter of the thin-walled metal ball 26 is D, the neutral layer diameter of the thin-walled metal tube 25 should be D, and the height of the thin-walled metal tube 25 is H = πD / 2. For example: the outer wall diameter of the thin-walled metal ball 26 is 10mm, and the inner wall diameter is 9mm. It can be seen that the neutral layer diameter of the thin-walled metal tube 25 should be D is 9.5mm, and the height of the thin-walled metal tube 25 is H = π×9.5 / 2≈14.9mm. The outer wall diameter of the thin-walled metal tube 25 can be set to 10mm, and the inner wall diameter can be set to 9mm.

[0062] A thin-walled metal ball 26 made of Q235 steel with an outer wall diameter of 10 mm and an inner wall diameter of 9 mm is prepared for further illustration. The main steps of the preparation method are as follows:

[0063] (1) preparing a thin-walled metal round tube 25 with an outer wall diameter of 10 mm, an inner wall diameter of 9 mm, and a height of 14.9 mm, and setting an outer chamfer 28 of 2° at both ends of the thin-walled metal round tube 25;

[0064] (2) heat treating the prepared thin-walled metal round tube 25. Specifically, a device with a controllable temperature range is used to heat treat different parts of the thin-walled metal round tube at different temperatures, so that the plasticity of the thin-walled metal round tube is gradually increased from the middle to the two ends;

[0065] (3) a layer of lubricant is evenly applied to the outer wall of the thin-walled metal tube 25, and the cavity wall of the first hemispherical cavity 7 and the cavity wall of the second hemispherical cavity 8 of the forming device;

[0066] (4) Place the thin-walled metal tube 25 into the cylindrical support body 3 of the forming device, ensure that the outer side of the bottom of the thin-walled metal tube 25 is located at the circumferential edge 81 of the second hemispherical cavity 8, the outer wall of the thin-walled metal tube 25 and the inner wall of the cylindrical support body 3 are matched with a small gap, the center line of the thin-walled metal tube 25 coincides with the center lines of the first hemispherical cavity 7, the second hemispherical cavity 8, and the cylindrical support body 3, and the upper end surface of the thin-walled metal tube 25 is flush with the upper surface of the cylindrical support body 3; the diameter of the first hemispherical cavity 7 and the second hemispherical cavity 8 is required to be 10 mm;

[0067] (5) Start the press and move the upper mold plate 1 downward at a speed of 200 mm / min. When the distance between the lower end face of the annular gasket 12 and the upper end face of the cylindrical support body 3 is 1-2 mm, reduce the downward speed of the upper mold plate 1 to 10-50 mm / min. The lower end face of the annular gasket 12 contacts the upper surface of the cylindrical support body 3. At this time, the circumferential edge 71 of the first hemispherical cavity 7 of the upper mold 5 contacts the top of the thin-walled metal circular tube 25. Then, during the mold closing process, the cylindrical support body 3 is pressed downward into the annular groove 9, forcing the thin-walled metal circular tube 25 to shrink and deform simultaneously under the action of pressure. The upper and lower ends of the cylindrical support body 3 are respectively subjected to the combined action of the tangential stress along the walls of the first hemispherical cavity 7 and the second hemispherical cavity 8, and the radial support force provided by the cylindrical support body 3. Finally, a thin-walled metal ball 26 is formed in the spherical cavity 10 after the mold closing.

[0068] Of course, under the premise of considering the influence of thickening caused by plastic deformation of the material on the size, the preferred outer wall diameter, inner wall diameter, height and other dimensions of the thin-walled metal circular tube 25, as well as the preferred downward speed of the press driving the upper template 1 to press down the cylindrical support body 3 and the thin-walled metal circular tube 25, can be gradually mastered through a limited number of tests. The size of the hemispherical cavities of the first hemispherical cavity 7 and the second hemispherical cavity 8 can also be selected according to actual processing needs.

[0069] The present invention provides a thin-walled metal ball forming device and the thin-walled metal ball manufactured by the same. The thin-walled metal ball 26 is manufactured by simultaneously shrinking the upper and lower ends of a thin-walled metal circular tube 25. Compared with the prior art, the machining and welding steps in the traditional thin-walled metal ball processing are omitted, and the technical problem that the weld is prone to cracking during liquid filling and bulging is fundamentally avoided, thereby improving product quality, significantly improving production and processing efficiency, and having a wide range of applications.

[0070] In the description of the present invention, it should be understood that the terms "left", "right", "up", "down", "top", "bottom", "front", "back", "inside", "outside", "back", "middle", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. It should be noted that in the above-mentioned embodiments, the "first" and "second" do not represent an absolute distinction in structure and / or function, nor do they represent a sequential execution order, but are merely for the convenience of description.

[0071] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, such as the materials of the upper mold 5, the lower mold 6 and the cylindrical support body 3 can be selected from different alloy materials as required, and the spring 4 can be selected from a suitable model as required, etc., should be included in the protection scope of the present application.

Claims

1. A method for preparing a thin-walled metal ball, characterized in that: The method comprises the following steps: placing a thin-walled metal round tube (25) between an upper die (5) and a lower die (6) of a forming device; closing the upper die (5) and the lower die (6) along the axial direction of the thin-walled metal round tube (25), shrinking and extruding the openings at both ends of the thin-walled metal round tube (25) at the same time, and finally forming the thin-walled metal ball (26) in a spherical cavity (10) formed by closing the upper die (5) and the lower die (6), and obtaining the thin-walled metal ball (26) after opening the die; The forming device is provided with an upper die (5) and a lower die (6); the upper die (5) is provided with a first hemispherical cavity (7); the lower die (6) is provided with a second hemispherical cavity (8); the first hemispherical cavity (7) and the second hemispherical cavity (8) are arranged opposite to each other with a spacing; when the upper die (5) and the lower die (6) are closed, the first hemispherical cavity (7) and the second hemispherical cavity (8) form the closed spherical cavity (10); The forming device is further provided with an upper mold plate (1), a lower mold plate (2) and an elastic member; the upper mold plate (1) is provided with the upper mold plate (5) and an annular gasket (12), and the lower mold plate (2) is provided with the lower mold plate (6); the lower mold plate (2) is provided with an installation blind hole, the lower mold plate (6) is arranged in the installation blind hole, and the side wall of the lower mold plate (6) and the side wall of the installation blind hole form an annular groove (9) with an upper opening; the upper end of the cylindrical support body (3) exposes the circumferential edge (81) of the second hemispherical cavity (8); the cylindrical support body (3) is connected to the annular groove (9) through the elastic member; the annular gasket (12) and the cylindrical support body (3) are arranged vertically opposite to each other; the upper mold plate (5) is arranged in the annular gasket (12); When the upper mold plate (1) and the lower mold plate (2) are molded together, the first hemispherical cavity (7) and the second hemispherical cavity (8) form the closed spherical cavity (10), and the cylindrical support body (3) is completely pressed downward into the annular groove (9) by the annular gasket (12); when the upper mold plate (1) and the lower mold plate (2) are molded together, the first hemispherical cavity (7) and the second hemispherical cavity (8) are separated from each other, and the cylindrical support body (3) and the upper mold plate (1) are separated from each other, and under the action of the elastic force of the elastic member, one end of the cylindrical support body (3) is exposed from the circumferential edge (81) of the second hemispherical cavity (8); The thin-walled metal ball is provided with, and only with, a pair of mounting through holes (18) or mounting protrusions (24) arranged opposite to each other on the ball wall of the thin-walled metal ball (26) along the central axis of the thin-walled metal ball (26).

2. The method for preparing a thin-walled metal ball according to claim 1, characterized in that: The forming device is also provided with a cylindrical support body (3), the cylindrical support body (3) is sleeved and connected with the lower mold (6), and the outer wall of the lower mold (6) is tightly attached to the inner wall of the cylindrical support body (3), the inner wall of the cylindrical support body (3) tightly surrounds the circumferential edge (81) of the second hemispherical cavity (8), and the cylindrical support body (3) and the lower mold (6) are connected to slide up and down; when the thin-walled metal circular tube (25) is placed in the cylindrical support body (3) between the upper mold (5) and the lower mold (6) of the forming device, the outer wall of the thin-walled metal circular tube (25) is matched with the inner wall of the cylindrical support body (3) with a small gap, and the outer side of the bottom of the thin-walled metal circular tube (25) is located at the circumferential edge (81) of the second hemispherical cavity (8).

3. The method for preparing a thin-walled metal ball according to claim 1, characterized in that: The plasticity of the thin-walled metal circular tube (25) gradually increases from the middle to both ends.

4. The method for preparing a thin-walled metal ball according to claim 1, characterized in that: The thin-walled metal circular tube (25) is provided with outer chamfers (28) at the tube openings at both ends thereof, respectively matching the contact surfaces of the first hemispherical cavity (7) and the second hemispherical cavity (8).

5. The method for preparing a thin-walled metal ball according to claim 1, characterized in that: Before placing the thin-walled metal round tube (25) between the upper die (5) and the lower die (6) of the forming device, lubricant is applied to the outer wall of the thin-walled metal round tube (25), the cavity wall of the first hemispherical cavity (7), and the cavity wall of the second hemispherical cavity (8).

6. The method for preparing a thin-walled metal ball according to claim 1, characterized in that: A residual material receiving groove (11) is provided at the bottom of each of the first hemispherical cavity (7) and the second hemispherical cavity (8).

7. The method for preparing a thin-walled metal ball according to claim 1, characterized in that: The lower die (6) remains stationary, and the upper die (5) is driven downward at a speed of 10-50 mm / min, thereby completing the extrusion forming of the thin-walled metal round tube (25).

8. The method for preparing a thin-walled metal ball according to claim 1, characterized in that: The forming device is also provided with a material ejecting device, the material ejecting device is provided with a material ejecting rod and a driving device, the material ejecting rod is a lead screw (15), and the driving device is a servo motor (16); the lower end of the lead screw (15) is coaxially connected to the power output end of the servo motor (16); the lead screw (15) is connected to the lower mold (6) through a nut (17) adapted thereto; the lead screw (15) causes the lower mold (6) to rise or fall along the inner wall of the cylindrical support body (3) under the power output of the servo motor (16); The lower mold plate (2) is provided with a first lower mold plate (21) and a second lower mold plate (22), and the first lower mold plate (21) and the second lower mold plate (22) are stacked and connected from top to bottom; the first lower mold plate (21) is provided with a through hole, and the side wall of the through hole, the side wall of the lower mold (6) and the upper surface of the second lower mold plate (22) form the annular groove (9) with an upper opening; the upper surface of the second lower mold plate (22) is provided with a spring mounting hole (19) and a lower mold limiting hole (20), respectively, and the spring mounting hole (19) is arranged at the bottom of the annular groove (9); the lower mold limiting hole (20) is arranged directly below the cylindrical support body (3), and the lower mold (6) is slidably connected in the lower mold limiting hole (20); A drive device mounting hole (23) is provided on the lower surface of the second lower mold plate (22), and the drive device mounting hole (23) is connected to the lower mold limit hole (20) via a connecting channel (27); the servo motor (16) is installed in the drive device mounting hole (23), and the lead screw (15) passes through the connecting channel (27) and is connected to the lower mold (6) via the nut (17).

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