Steel cylinder stretching forming die

Abstract

The utility model discloses a steel cylinder stretching forming die which comprises an upper die body, and the upper die body is provided with an upper die frame and a punching assembly arranged in the upper die frame. The lower die body is provided with an end socket male die; at least one of the upper die body and the lower die body can axially move along the central axis of the upper die body and the central axis of the lower die body under the action of external driving force, so that the upper die body and the lower die body are close to each other or far away from each other, and a hole is formed in the top of a stretching part through the cooperation of the punching assembly and the end socket male die. In the process that the disc plate body is stretched into the steel cylinder, punching is conducted on the disc plate body, the procedure of independently punching a stretching piece after the stretching procedure is completed is omitted, punching is completed in the stretching procedure, and the hole forming quality can be guaranteed through cooperation of the punching assembly and the end socket male die.

Description

Technical Field

[0001] This utility model belongs to the field of steel cylinder manufacturing technology, specifically relating to steel cylinder stretch forming molds. Background Technology

[0002] Liquefied petroleum gas (LPG), as a common fuel, has rapidly entered thousands of households due to its convenience, speed, and cleanliness. As a result, LPG cylinders have become the most widely used pressure vessels in China. A traditional LPG cylinder consists of a valve body, an upper cylinder body, and a lower cylinder body. The upper and lower cylinder bodies are both made from disc plates through a stretching die to form cylindrical bodies. The two cylinder bodies are then welded together to form a steel container capable of holding the medium.

[0003] In the production of liquefied petroleum gas cylinders, stretching is an important and critical process. While conducting research on the quality problems and safety hazards of the cylinder stretching process in the early stages, the applicant submitted a patent application with application number CN2020109251852, which discloses a cylinder end cap stretching system and process. Through improvements to the stretching die structure, the new process eliminates the need for a pressure cylinder and removes the corresponding hydraulic structure. While retaining some of the original cylinder system, it can share the same hydraulic system, thereby achieving a 50% energy saving effect. Because the working stroke of the new process is shorter than that of the current process, the stretching speed of the new process is faster under the same conditions, which is conducive to high efficiency and energy saving.

[0004] Further research by the applicant revealed that while the technical solution improved energy consumption and fracture quality in the stretch forming of steel cylinders, it also caused problems when assembling the valve body after stretch forming. This was because the steel cylinder needed to be punched separately. Due to the additional punching process, the punched holes deviated from the preset positions. As a result, subsequent positioning, welding, and assembly based on the punched holes encountered a series of problems, such as poor welding quality, misalignment of the valve body assembly, and fluctuations in geometric tolerances. Utility Model Content

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A steel cylinder stretch forming die, comprising:

[0007] The upper mold body includes an upper mold frame and a punching assembly disposed in the upper mold frame;

[0008] The lower mold body has a head punch;

[0009] At least one of the upper mold body and the lower mold body can move axially along their central axis under the action of external driving force, so that the upper mold body and the lower mold body move closer to each other or further away from each other, and the top of the drawn part is opened by the punching assembly cooperating with the head punch.

[0010] The punching assembly includes a punching sleeve connected to the upper die set, a punch mechanism placed inside the punching sleeve, and a pre-punching mechanism coaxially arranged with the punch mechanism.

[0011] Furthermore, the pre-punching mechanism includes several circumferentially distributed adjusting rods and a material ejection block. One end of each adjusting rod is connected to the material ejection block, and the other end passes through the punch sleeve. A spring is provided between the punch mechanism and the material ejection block.

[0012] Furthermore, the punch mechanism includes a punch seat and a punch.

[0013] Furthermore, the end cap punch has a stepped hole at the top, and the stepped hole is conforming to the shape of the punch.

[0014] Furthermore, the lower die body also includes a blank holder that can move axially around the outer periphery of the head punch. At least one pair of lower die pressure irons are provided on the edge of the blank holder, and a blank holder ring is coaxially provided on the upper end of the blank holder. The thickness of the lower die pressure iron is greater than the thickness of the blank holder ring.

[0015] Furthermore, the lower mold body also includes a lower mold base plate, which has several sets of lower mold limiting rods. The pressure plate seat is penetrated by the lower mold limiting rods, and the pressure plate ring can be adjusted to move back up to the maximum stroke through the mold limiting rods.

[0016] Furthermore, several sliding push rods are connected between the lower mold base plate and the pressure plate seat.

[0017] Furthermore, the upper mold body also includes an upper concave mold connected to the bottom of the upper mold frame, and at least one set of upper mold pressure irons connected to the upper mold frame are distributed on the outer circumferential side of the upper concave mold.

[0018] Furthermore, the thickness of the upper die pressing iron is equal to that of the upper die.

[0019] Furthermore, the bottom of the upper mold frame is also connected to several pairs of guide seats, and the lower mold body is provided with guide pillars that cooperate with the guide seats.

[0020] Compared with the prior art, this utility model has the following advantages:

[0021] By setting a punching component in the upper mold body, the disc plate is punched during the stretching process into a steel cylinder, eliminating the need for a separate punching process on the stretched part after the stretching process. Since the punching is completed in the stretching process, the quality of the hole can be guaranteed through the cooperation of the punching component and the end cap punch.

[0022] The punching assembly of this mold body uses a pre-punching mechanism, which makes it less likely for the stretched steel cylinder to shake or tilt during the punching process. The punched holes can maintain good concentricity with the main body of the steel cylinder, which provides a good guarantee for subsequent benchmark positioning, welding, valve assembly and other processes. Attached Figure Description

[0023] Figure 1 This is a three-dimensional structural diagram of one embodiment of the mold of this utility model;

[0024] Figure 2 This is a cross-sectional structural diagram of one embodiment of the mold of this utility model;

[0025] Figure 3 This is a three-dimensional structural diagram of the second embodiment of the mold of this utility model;

[0026] Figure 4 This is a cross-sectional structural diagram of the second embodiment of the mold of this utility model;

[0027] Figure 5 This is a three-dimensional structural diagram of three embodiments of the mold of this utility model;

[0028] Figure 6 This is a cross-sectional structural diagram of three embodiments of the mold of this utility model;

[0029] Figure 7 This is an exploded structural diagram of the upper mold body in an embodiment of the present invention.

[0030] Figure 8 This is an exploded structural diagram of the lower mold body in an embodiment of the present invention.

[0031] Figure 9 This is a cross-sectional view of the punching assembly in an embodiment of the mold of this utility model;

[0032] Figure 10 This is a cross-sectional structural schematic diagram of the tension member according to an embodiment of the present utility model;

[0033] The reference numerals in the accompanying drawings include:

[0034] Upper mold body 1, upper mold frame 10, punching assembly 11, punching sleeve 110, punch seat 111, punch 112, adjusting rod 113, ejector block 114, spring 115, upper die 12, upper die pressure iron 13, guide seat 14, lower mold body 2, end cap punch 20, stepped hole 200, punch connecting seat 201, pressure seat 21, lower die pressure iron 22, pressure ring 23, mold base plate 24, lower die limiting rod 25, sliding ejector rod 26, guide post 27, stretching part 3, disc plate 30. Detailed Implementation

[0035] To enable those skilled in the art to better understand this utility model, the technical solution of this utility model will be further described below in conjunction with the accompanying drawings and embodiments.

[0036] The accompanying drawings are for illustrative purposes only and represent schematic diagrams, not actual physical objects. They should not be construed as limiting the scope of this patent. To better illustrate the embodiments of this utility model, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The same or similar reference numerals in the drawings of the embodiments of this utility model correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" appear, indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms describing positional relationships in the drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0037] like Figures 1-10 As shown, the steel cylinder stretch forming mold of this utility model includes an upper mold body 1 and a lower mold body 2;

[0038] The upper mold body 1 includes an upper mold frame 10 and a punching assembly 11 placed in the upper mold frame 10;

[0039] The lower mold body 2 has a head punch 20, which is highly conformally fitted to the drawing part 3;

[0040] At least one of the upper mold body 1 and the lower mold body 2 can move axially along their central axis under the action of external driving force, so that the upper mold body 1 and the lower mold body 2 move closer or further away from each other, and the top of the drawn part 3 is opened by the punching assembly 11 cooperating with the end cap punch 20.

[0041] The punching assembly 11 includes a punching sleeve 110 connected to the upper die set 10, a punch 112 mechanism placed inside the punching sleeve 110, and a pre-punching mechanism coaxially arranged with the punch 112 mechanism.

[0042] By setting a punching component 11 inside the upper mold body 1, punching is performed on the disc plate 30 during the process of stretching it into a steel cylinder. This eliminates the need to punch the stretched part 3 separately after the stretching process is completed. Since the punching is completed during the stretching process, the quality of the hole can be guaranteed through the cooperation of the punching component 11 and the end cap punch 20.

[0043] In this embodiment, the external driving force is a hydraulic press, which applies downward pressure to the upper mold body 1, forcing the upper mold body 1 to move closer to the lower mold body 2, and stretching the disc plate 30 placed on the pressure seat 21.

[0044] The punching assembly 11 of the mold body 1 uses a pre-punching mechanism, which makes it less likely for the stretched steel cylinder to shake or tilt during the action of the punch 112 mechanism. The punched hole can maintain good concentricity with the main body of the steel cylinder, which provides a good guarantee for subsequent benchmark positioning, welding, valve assembly and other processes.

[0045] Specifically, such as Figure 9 As shown, the pre-punching mechanism includes several circumferentially distributed adjusting rods 113 and a material ejection block 114. One end of the adjusting rod 113 is connected to the material ejection block 114, and the other end passes through the punch sleeve 110. A spring 115 is provided between the punch 112 mechanism and the material ejection block 114.

[0046] The punch 112 mechanism includes a punch base 111 and a punch 112. The two are threadedly connected, and the punch 112 can be disassembled and replaced to meet the needs of punching holes of different diameters.

[0047] Because the bottom of the ejector block 114 is concave and conforms to the shape of the end cap punch 20, and a concave hole is provided in the center for the punch to enter or retract, after the ejector block 114 contacts the top of the formed steel cylinder, it fits the steel cylinder well. As the upper mold body 1 and the lower mold body 2 approach each other, the spring 115 is compressed. The punch 112 acts on the stretching part through the above-mentioned concave hole and the upper mold, and enters the stepped hole 200.

[0048] This configuration ensures that the ejector block 114 applies force evenly to the top of the stretched steel cylinder, preventing it from shifting after being acted upon by the subsequent punch 112 mechanism.

[0049] In addition, holes are made in the punch sleeve 110, and the displacement stroke distance of the ejector block 114 is controlled by adjusting the rod 113 through which a nut is set at the end of the adjusting rod 113.

[0050] like Figure 8 As shown, the top of the end cap punch 20 has a stepped hole 200, which is adapted to the shape of the punch 112.

[0051] In addition, this application has made further improvements to the cylinder stretching process. Specifically, the lower die body 2 also includes a pressure seat 21 that can move axially around the outer periphery of the head punch 20. At least one pair of lower die pressure irons 22 are provided on the edge of the pressure seat 21. A pressure ring 23 is coaxially provided on the upper end of the pressure seat 21. The thickness of the lower die pressure iron 22 is greater than the thickness of the pressure ring 23.

[0052] The upper mold body 1 includes an upper die 12 connected to the bottom of the upper mold frame 10, and at least one set of upper mold pressure irons 13 connected to the upper mold frame 10 are distributed on the outer circumferential side of the upper die 12.

[0053] In the existing stretching process, the formed steel cylinder has unevenness at the stretching fracture. The reason is that the pressure of the pressure cylinder used is constant. At the beginning of stretching and during the process, the pressure on the stretching part 3 per unit area is not too large. However, as stretching progresses, especially towards the end, the pressure will be concentrated at the tail of the end-cap punch 20. The pressure on the stretching part 3 per unit area will be very large and uneven. The tail of the stretched cylinder is elongated and irregular. Even if subsequent cutting or other treatments are carried out, the metallographic structure of the stretching part 3 wall will become loose and damaged, which is irreversible.

[0054] The biggest problem is the existence of significant hidden safety risks. Some cylinders with hidden, inconspicuous, unbroken, or undetected damaged metallographic structures are sent to the next process for further treatment, and these problems are not specifically inspected, leading to their neglect and the fundamental problem not being eradicated.

[0055] This technical solution employs corresponding upper concave dies 12 and pressure rings 23 in the upper mold body 1 and lower mold body 2, respectively. Based on the basic structure for the stretching process of the disc plate 30, the paired upper die pressure irons 13 and lower die pressure irons 22 prevent excessive stretching of the forming die, thus avoiding safety risks at the tail end of the cylindrical extension part. Figures 1-6 The diagram shows the three process states before, during, and after the stretching process.

[0056] Because of the presence of an upper die pressure iron 13 and a lower die pressure iron 22, the lower die pressure iron 22 is thicker than the pressure ring 23 and protrudes to a certain height, while the upper die pressure iron 13 is equal in thickness to the upper die 12. When combined with the upper die body 1, there is a gap between the upper die 12 and the pressure ring 23, which prevents the die from being pulled to the bottom or over-extended, thus avoiding edge pulling. Due to the existence of the above-mentioned gap, there is no actual edge pressing process at the tail of the cylindrical stretching part 3, so there will be no unevenness at its break point. This gap is generally no more than 3mm.

[0057] like Figure 8 As shown, the lower mold body 2 also includes a lower mold base plate 24, which has several sets of lower mold limiting rods 25. The pressure plate seat 21 is penetrated by the lower mold limiting rods 25. Through the mold limiting rods, the pressure plate ring 23 can be adjusted to move back up to the maximum stroke.

[0058] The lower die limit rod 25 is equipped with an adjusting nut at its end. By turning the nut, the amount of retraction of the pressure plate seat 21 can be controlled, thereby adjusting the distance between the upper die 12 and the pressure ring 23 to match the thickness of the disc plate 30.

[0059] The above solution eliminates the severe unevenness of the stretched part 3 by setting a lower die pressure iron 22 and an upper die pressure iron 13 at the end of the stretching process, and by having an adjustable pressure seat 21.

[0060] The steel cylinders formed by stretching using this mold will not have a porous metallographic structure on the cylinder wall, thus eliminating potential safety hazards in pressure vessels. At the same time, they can maintain good shape accuracy, improve product quality, and also benefit the quality of subsequent processes such as welding.

[0061] like Figure 8 As shown, several sliding ejector rods 26 are connected between the lower mold base plate 24 and the pressure plate seat 21. After the lower mold body 2 is acted upon by the upper mold body 1, the pressure plate seat 21 exerts downward pressure on the sliding ejector rods 26. After stretching and forming, the upper mold body 1 retracts, and the sliding ejector rods 26 push the pressure plate seat 21 together with the pressure plate ring 23 to return to the initial state.

[0062] In addition, to prevent wobbling or misalignment during relative movement of the upper mold body 1 and the lower mold body 2, several pairs of guide seats 14 are connected to the bottom of the upper mold frame 10, and guide posts 27 that cooperate with the guide seats 14 are provided in the lower mold body 2. The cooperation between the guide posts 27 and the guide seats 14 makes the sliding of the two closer or further apart more smooth.

[0063] The end cap die 20 is provided with a die connecting seat 201 at the bottom. Through the die connecting seat 201, the end cap die 20 is detachably connected to the die base plate 24. This setting method allows for the replacement of the end cap die 20 according to the size and shape of the steel cylinder to be stretched, which is quite convenient.

[0064] The above are merely embodiments of this utility model. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, based on the guidance provided in this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of this utility model. These should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent.

Claims

1. A steel cylinder stretch forming die, characterized in that, include: The upper mold body includes an upper mold frame and a punching assembly disposed in the upper mold frame; The lower mold body has a head punch; At least one of the upper mold body and the lower mold body can move axially along their central axis under the action of external driving force, so that the upper mold body and the lower mold body move closer to each other or further away from each other, and the top of the drawn part is opened by the punching assembly cooperating with the head punch. The punching assembly includes a punching sleeve connected to the upper die set, a punch mechanism placed inside the punching sleeve, and a pre-punching mechanism coaxially arranged with the punch mechanism.

2. The cylinder stretch forming die as described in claim 1, characterized in that: The pre-punching mechanism includes several circumferentially distributed adjusting rods and a material ejection block. One end of each adjusting rod is connected to the material ejection block, and the other end passes through the punch sleeve. A spring is provided between the punch mechanism and the material ejection block.

3. The cylinder stretch forming die as described in claim 1 or 2, characterized in that: The punch mechanism includes a punch base and a punch.

4. The cylinder stretch forming die as described in claim 3, characterized in that: The end cap punch has a stepped hole at the top, which is conformable to the shape of the punch.

5. The cylinder stretch forming die as described in claim 1, 2, or 4, characterized in that: The lower die body also includes a blank holder that can move axially around the outer periphery of the end cap punch. The edge of the blank holder is provided with at least a pair of lower die pressure irons, and a blank holder ring is coaxially provided at the upper end of the blank holder. The thickness of the lower die pressure iron is greater than the thickness of the blank holder ring.

6. The cylinder stretch forming die as described in claim 5, characterized in that: The lower mold body also includes a lower mold base plate, which has several sets of lower mold limiting rods. The pressure plate seat is penetrated by the lower mold limiting rods. Through the mold limiting rods, the pressure plate ring can be adjusted to move back up to the maximum stroke.

7. The cylinder stretch forming die as described in claim 6, characterized in that: Several sliding push rods are connected between the lower mold base plate and the pressure seat.

8. The cylinder stretch forming die as described in claim 1, 2, 4, 6, or 7, characterized in that: The upper mold body also includes an upper concave mold connected to the bottom of the upper mold frame, and at least one set of upper mold pressure irons connected to the upper mold frame are distributed on the outer circumferential side of the upper concave mold.

9. The cylinder stretch forming die as described in claim 8, characterized in that: The thickness of the upper die pressing iron is equal to that of the upper die.

10. The cylinder stretch forming die as described in claim 8, characterized in that: The bottom of the upper mold frame is also connected to several pairs of guide seats, and the lower mold body is provided with guide pillars that cooperate with the guide seats.

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