Oil cylinder for large ring forging press, forging and pressing system and forging and pressing method

Abstract

The invention discloses an oil cylinder for a large ring forging press, a forging system and a forging method. The oil cylinder comprises a cylinder barrel, a first piston rod and a second piston rod. One end of the cylinder barrel and one end of the first piston rod are closed, the other end of the cylinder barrel and the other end of the first piston rod are open, the second piston divides an inner cavity of the first piston rod into a perforated rod cavity and a perforated rodless cavity, and the first piston rod is provided with a middle oil channel extending in the axial direction. The middle oil duct is communicated with the outside through a first oil port and is communicated with a perforated rodless cavity through a second oil port, the perforated rodless cavity is communicated with a third oil port in the surface of the first piston rod, and the first oil port and the third oil port are both arranged close to the opening end of the first piston rod, so that in the reciprocating motion process of the first piston rod, the second oil port is communicated with the middle oil duct. The first oil port and the third oil port are located outside the cylinder barrel all the time. The second piston rod and the first piston rod do not need to be mutually linked in movement, the second piston rod and the first piston rod can move independently, and two independent operations of upsetting and punching are achieved.

Description

Technical Field

[0001] This invention relates to the field of press design technology, and in particular to a hydraulic cylinder, forging system and forging method for a large ring forging press. Background Technology

[0002] Ring forging presses are mainly used to produce various metal ring parts. The key processes include upsetting and punching, which can process solid bars into ring blanks. Since the press requires high pressure output, the output force of the hydraulic cylinder is required to be high. Therefore, traditional ring forging presses use plunger-type hydraulic cylinders. The hydraulic cylinder can only output thrust and cannot retract on its own. It needs to rely on the action of an external return cylinder to bring the piston rod back.

[0003] Furthermore, traditionally, upsetting and punching are performed at separate processing stations. The main hydraulic cylinder moves the moving beam downwards, with different stations below it: an upsetting station and a punching station, each arranged in parallel. Because of this dual-station setup, neither the upsetting nor the punching station is centered on the moving beam. Therefore, during the upsetting process, the workpiece is not directly beneath the moving beam, leading to an unbalanced force and a large bending moment, significantly impacting the beam's lifespan. Additionally, the next step, punching, requires manual transfer of the workpiece, consuming labor and reducing production efficiency.

[0004] While ordinary multi-stage hydraulic cylinders can also achieve multi-stage output, they are not suitable for forging presses because: (1) insufficient thrust; (2) the internal and external cavities of multi-stage hydraulic cylinders are interconnected, and the movement of the piston rod is linked, making independent movement impossible; and (3) a large piston rod length or a heavy hydraulic cylinder can easily lead to reduced machining accuracy and increased machining energy consumption.

[0005] In summary, designing a hydraulic cylinder for ring forging presses that can perform upsetting and stamping operations in the same station is a technical problem that needs to be solved. Summary of the Invention

[0006] To address the technical problem of insufficient thrust and the inability of each piston rod to move independently in existing multi-stage hydraulic cylinders, this invention provides a hydraulic cylinder for a large ring forging press to solve the above problems.

[0007] To address the technical problem that existing ring forging presses require upsetting and punching to be performed at different processing stations, resulting in reduced service life of the moving beam and decreased production efficiency, this invention provides a forging system and forging method to solve the above problems.

[0008] This invention proposes a hydraulic cylinder for a large ring forging press, comprising a cylinder barrel, a first piston rod located inside the cylinder barrel, and a second piston rod located inside the first piston rod. A first piston is provided between the first piston rod and the cylinder barrel, and a second piston is provided between the second piston rod and the first piston rod. The first piston divides the internal cavity of the cylinder barrel into a rod-side chamber of the main cylinder and a rodless chamber of the main cylinder.

[0009] Both the cylinder and the first piston rod are closed at one end and open at the other. The second piston divides the internal cavity of the first piston rod into a perforated rod cavity and a perforated rodless cavity. The first piston rod has an axially extending intermediate oil passage. The intermediate oil passage is connected to the outside through a first oil port on the outer surface of the first piston rod and to the perforated rodless cavity through a second oil port on the inner surface of the first piston rod. The perforated rod cavity is connected to a third oil port on the surface of the first piston rod. The first oil port and the third oil port are both located close to the open end of the first piston rod, so that during the reciprocating motion of the first piston rod, the first oil port and the third oil port are always located outside the cylinder.

[0010] In an optional embodiment of the present invention, a closed hollow cavity is provided inside the first piston rod.

[0011] In an optional embodiment of the present invention, an annular retraction groove is provided on the inner bottom surface of the perforated rodless cavity, and the annular retraction groove serves as a second oil port communicating with the oil passage.

[0012] In an optional embodiment of the present invention, a displacement sensor is installed on the inner bottom surface of the first piston rod, which is directly opposite the end of the second piston rod.

[0013] In an optional embodiment of the present invention, the cylinder includes a cylinder body and a cylinder bottom located at one end of the cylinder body. The cylinder bottom is provided with a radial oil passage and an axial oil passage that communicate with each other. The radial oil passage extends to the surface of the cylinder bottom to form a fourth oil port. The axial oil passage is located at the center of the cylinder bottom and communicates with the rodless chamber of the main cylinder.

[0014] In an optional embodiment of the present invention, an expansion ring is provided between the radial contact surface of the cylinder body and the bottom of the cylinder, and the radial inner surface of the expansion ring has one or more arc-shaped protrusions spaced apart.

[0015] In an optional embodiment of the present invention, the first piston rod is connected to the cylinder opening end by a first sealing assembly. The first sealing assembly includes a U-shaped sealing ring, a first copper sleeve, a first V-shaped sealing ring group and a second copper sleeve arranged sequentially along the axial direction. The first copper sleeve and the second copper sleeve abut against both ends of the first V-shaped sealing ring group. The U-shaped sealing ring is limited by the first piston rod and the cylinder. The cylinder has an oil drain port located between the U-shaped sealing ring and the first copper sleeve.

[0016] In an optional embodiment of the present invention, the first piston and the cylinder are connected by a second sealing assembly. The second sealing assembly includes a Glyd ring and a second V-shaped sealing ring assembly. The Glyd ring is located on the rod chamber side of the main cylinder. The second V-shaped sealing ring assembly has a triangular retaining ring at the outer apex of the side facing the Glyd ring. The contact surface between the triangular retaining ring and the second V-shaped sealing ring assembly is an inclined surface. An elastic body is provided on the inner circumference of the Glyd ring, and a reinforcing retaining ring is provided on the outer apex of the side facing the second V-shaped sealing ring assembly.

[0017] The present invention also proposes a forging system, including a frame, a worktable, a moving beam located above the worktable, and a hydraulic cylinder for a large ring forging press as described above. The cylinder barrel of the hydraulic cylinder for the large ring forging press is fixed to the frame, the first piston rod passes through the moving beam and is fixed thereto, and the hydraulic cylinder for the large ring forging press is located at the center of the moving beam.

[0018] In an optional embodiment of the present invention, the open end of the first piston rod is provided with a guide sleeve and a retaining ring. The guide sleeve has a guide cylinder that contacts the outer peripheral surface of the second piston rod and an end cap that contacts the end face of the first piston rod. The retaining ring is secured to the outer periphery of the first piston rod. The end cap contacts the upper end face of the moving beam. The retaining ring is fixed to the moving beam by bolts. The retaining ring is formed by splicing at least two arc-shaped blocks.

[0019] The present invention also proposes a forging method, comprising the following steps: S1: Upsetting; the rodless chamber of the main cylinder is pressurized, pushing the first piston rod to extend, which in turn drives the moving beam to apply positive pressure to the workpiece.

[0020] S2: Calibration; After the upsetting is completed, control the position of the first piston rod to keep the moving beam in contact with the workpiece.

[0021] S3: Punching; The first piston rod remains stationary, pressurizing the rodless cavity for perforation, pushing the second piston rod to extend and punch the workpiece.

[0022] S4: The second piston rod retracts; the first piston rod remains stationary, pressurizing the rod chamber of the perforation, pushing the second piston rod to retract, and the punch at the end of the second piston rod leaves the workpiece.

[0023] S5: The first piston rod retracts; pressure is applied to the rod chamber of the main cylinder, pushing the first piston rod to retract, the moving beam is pulled back, and it separates from the workpiece.

[0024] The beneficial effects of this invention are: (1) The hydraulic cylinder for the large ring forging press of the present invention has an intermediate oil passage in the first piston rod. By staggering the arrangement of the first oil port and the second oil port, the two oil inlets that drive the second piston rod can always be located outside the cylinder during the reciprocating motion of the first piston rod. Therefore, it does not need to be linked with the movement of the first piston rod. The two can move independently to realize the two independent operations of upsetting and punching.

[0025] (2) The hydraulic cylinder for the large ring forging press described in this invention has a design where one end of the cylinder barrel and the first piston rod are closed and the other end is open. The area of ​​the rodless cavity in each piston rod is larger than the area of ​​the rod cavity, thereby increasing the thrust of the piston rod and meeting the high pressure output requirements.

[0026] (3) The forging system and forging method described in this invention replace the traditional plunger-type hydraulic cylinder with a piston-type hydraulic cylinder, eliminating the need for an external return cylinder, making the equipment more efficient and simple.

[0027] (4) The forging system and forging method described in this invention integrate the upsetting and piercing functions into one hydraulic cylinder, which greatly reduces equipment space, forging time and labor intensity of workers, improves production efficiency and extends equipment service life. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Figure 1 This is an axial sectional view of a specific embodiment of the hydraulic cylinder for a large ring forging press according to the present invention; Figure 2 yes Figure 1 Enlarged view of point a in the middle; Figure 3 yes Figure 2 Enlarged view of the sealing area of ​​the middle Glyd ring; Figure 4 yes Figure 1 Enlarged view at point b; Figure 5 This is a schematic diagram of the use of the hydraulic cylinder for the large ring forging press described in this invention in the forging system; Figure 6 This is a perspective view of the expansion ring in this invention; Figure 7 This is a schematic cross-sectional view of the cable channel in the hydraulic cylinder of the large ring forging press described in this invention.

[0030] In the diagram, 1. Cylinder barrel, 101. Cylinder body, 102. Cylinder bottom, 2. First piston rod, 3. Second piston rod, 4. First piston, 5. Second piston, 6. Main cylinder rod chamber, 7. Main cylinder rodless chamber, 8. Perforated rod chamber, 9. Perforated rodless chamber, 10. Intermediate oil passage, 11. First oil port, 12. Second oil port, 13. Snap ring, 14. Hollow cavity, 15. Welding point, 16. Displacement sensor, 17. Cable channel, 18. Radial oil passage, 19. Axial oil passage, 20. Fourth oil port, 21. Expansion ring, 2101. Arc-shaped protrusion. 22. First sealing assembly; 2201. U-shaped sealing ring; 2202. First copper sleeve; 2203. First V-shaped sealing ring assembly; 2204. Second copper sleeve; 2205. Retaining ring; 23. Oil drain port; 24. Second sealing assembly; 2401. Glyd ring; 2402. Second V-shaped sealing ring assembly; 2403. Triangular retaining ring; 2404. Elastomer; 2405. Reinforcing retaining ring; 25. Moving beam; 26. Guide sleeve; 2601. Guide cylinder; 2602. End cap; 27. Oil cylinder; 28. Worktable; 29. ​​Annular retraction groove. Detailed Implementation

[0031] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0032] Example 1 like Figure 1 As shown, a hydraulic cylinder for a large ring forging press includes a cylinder barrel 1, a first piston rod 2 located inside the cylinder barrel 1, and a second piston rod 3 located inside the first piston rod 2. A first piston 4 is provided between the first piston rod 2 and the cylinder barrel 1, and a second piston 5 is provided between the second piston rod 3 and the first piston rod 2. The first piston 4 divides the internal cavity of the cylinder barrel 1 into a rod chamber 6 of the main cylinder and a rodless chamber 7 of the main cylinder.

[0033] For ease of description, the direction in which the piston rod extends is forward, and the direction in which the piston rod retracts is backward.

[0034] Both cylinder 1 and first piston rod 2 are closed at one end and open at the other. Second piston 5 divides the internal cavity of first piston rod 2 into a perforated rod chamber 8 and a perforated rodless chamber 9. Figure 1As shown, both the cylinder 1 and the first piston rod 2 are closed at the rear and open at the front. The first piston rod 2 extends from the front end of the cylinder 1, and the first piston 4 is located on the outer periphery of the first piston rod 2 and close to the rear end. Thus, the rear end of the first piston rod 2 and the rear end of the cylinder 1 form the rodless chamber 7 of the main cylinder, and the outer wall of the first piston rod 2 and the inner wall of the cylinder 1 form the rod-side chamber 6 of the main cylinder. Comparatively, the area of ​​the rodless chamber 7 is much larger than the area of ​​the rod-side chamber 6, resulting in a larger pushing force of the first piston rod 2. Similarly, the area of ​​the perforated rodless chamber 9 is much larger than the area of ​​the perforated rod-side chamber 8, thus the pushing force of the second piston rod 3 is larger, meeting the high-pressure output requirements of the press. The retraction pressure requirement is lower, so the retraction driving force can be less than the pushing driving force. This satisfies both the working requirements of the press and ensures the structural strength of the piston rod.

[0035] The first piston rod 2 has an axially extending intermediate oil passage 10. The intermediate oil passage 10 is connected to the outside through a first oil port 11 on the outer surface of the first piston rod 2 and to the perforated rodless cavity 9 through a second oil port 12 on the inner surface of the first piston rod 2. The perforated rod cavity 8 is connected to a third oil port on the surface of the first piston rod 2 (the third oil port is not shown). The first oil port 11 and the third oil port are both located close to the open end of the first piston rod 2, so that during the reciprocating motion of the first piston rod 2, the first oil port 11 and the third oil port are always located outside the cylinder 1. Since the perforated rodless cavity 9 is located at the rear end of the second piston rod 3, if the perforated rodless cavity 9 is directly connected to the radial oil port, the oil port will also be close to the rear end of the second piston rod 3, which is approximately located in the middle of the first piston rod 2 in the figure. When the first piston rod 2 retracts, the oil port will retract into the cylinder 1 and cannot connect to external hydraulic oil. Therefore, the present invention achieves the connection between the perforated rodless cavity 9 and the outside by using the first oil port 11 and the second oil port 12 that are staggered front and rear and the intermediate oil passage 10 connecting the two oil ports. At this time, the first oil port 11 can be set at the front end of the first piston rod 2 and will not retract into the cylinder 1, so that the movement of the first piston rod 2 and the movement of the second piston rod 3 are independent of each other. When the first piston rod 2 is fully extended, the second piston rod 3 will not extend immediately, but will extend according to the time set by the program.

[0036] Master cylinder oil inlet method: The cylinder 1 includes a cylinder body 101 and a cylinder bottom 102 located at one end of the cylinder body 101. Both the rod chamber 6 and the rodless chamber 7 of the main cylinder can be selected to receive oil from the side of the cylinder body 101. In this embodiment, the rodless chamber 7 of the main cylinder receives oil from the cylinder bottom 102. For example... Figure 1 As shown, the cylinder bottom 102 is provided with a radial oil passage 18 and an axial oil passage 19 that are interconnected. The radial oil passage 18 extends to the surface of the cylinder bottom 102 to form a fourth oil port 20, and the axial oil passage 19 is located at the center of the cylinder bottom 102 and is connected to the rodless chamber 7 of the main cylinder.

[0037] Structure of the first piston rod 2: Because the punching stroke is shorter, the stroke of the second piston rod 3 is shorter than that of the first piston rod 2. Therefore, the length of the cavity in the first piston rod 2 that houses the second piston rod 3 is smaller; for example, the rear end of the first piston rod 2 may have a longer solid section. However, this would make the first piston rod 2 too heavy, requiring higher retraction power. Therefore, in this embodiment, a closed hollow cavity 14 is preferably provided inside the first piston rod 2. Figure 1 As shown, the hollow cavity 14 is located behind the second piston rod 3. The hollow cavity 14 has a split structure, as shown... Figure 1 As shown, the hollow cavity 14 is divided into three sections: front, middle and rear. The three sections are welded and fixed in sequence. The four triangular areas in the figure are the welding points 15.

[0038] To ensure the accuracy of the punching length, in this embodiment, a displacement sensor 16 is installed on the inner bottom surface of the first piston rod 2, which is directly opposite the end of the second piston rod 3. This displacement sensor 16 can measure the extension length of the second piston rod 3. The displacement sensor 16 can be connected to an external power source through a cable channel 17 inside the first piston rod 2.

[0039] Example 2 In Embodiment 1, the second oil port 12 located on the inner wall of the first piston rod 2 can be formed by drilling. Since the second oil port 12 does not extend to the outside of the first piston rod 2, it can only be processed inside the first piston rod 2. Due to space limitations, the drilling operation is quite difficult.

[0040] Normally, to avoid stress concentration, a relief groove is machined at the connection between the inner bottom surface and the side wall of the perforated rodless cavity 9. The relief groove is machined into an annular shape by turning. Therefore, in this embodiment, the annular relief groove 29 and the second oil port 12 are combined into one, that is, the annular relief groove 29 is extended to communicate with the intermediate oil passage 10.

[0041] Example 3 Based on the above embodiments, an expansion ring 21 is provided between the radial contact surfaces of the cylinder body 101 and the cylinder bottom 102, and the radial inner surface of the expansion ring 21 has one or more arc-shaped protrusions 2101 spaced apart (e.g., Figure 6(As shown). The function of the expansion ring 21 is to expand under oil pressure, ensuring that the outer wall of the expansion ring 21 is always in contact with the cylinder 101. This prevents the cylinder 101 from expanding and deforming, which could cause a gap between the cylinder 101 and the cylinder bottom 102, resulting in oil leakage. In this embodiment, oil enters the expansion ring 21 through the gap between the expansion ring 21 and the cylinder bottom 102 formed between adjacent arc-shaped protrusions 2101, instead of entering oil from the center of the expansion ring 21 in the traditional way. With the expansion ring 21 structure in this embodiment, there is no need to specially set up an oil passage for the expansion ring 21, and the direction of hydraulic oil entering the expansion ring 21 is the same as the direction of oil leakage. When there is a risk of oil leakage, the oil will first enter the expansion ring 21, and the sealing gap will be adjusted by the expansion ring 21.

[0042] Example 4 Based on the above embodiments, this embodiment features a special design for the seal at the piston rod. Due to the higher hydraulic pressure, the sealing requirements are higher than those for ordinary hydraulic cylinders. This mainly refers to the connection between the first piston rod 2 and the open end of the cylinder barrel 1.

[0043] The first piston rod 2 is connected to the open end of the cylinder 1 through the first sealing assembly 22, such as Figure 4 As shown, the first sealing assembly 22 includes a U-shaped sealing ring 2201, a first copper sleeve 2202, a first V-shaped sealing ring group 2203, and a second copper sleeve 2204 arranged sequentially along the axial direction. The first V-shaped sealing ring group 2203 consists of multiple V-shaped sealing rings connected in sequence. The first copper sleeve 2202 and the second copper sleeve 2204 abut against both ends of the first V-shaped sealing ring group 2203. The U-shaped sealing ring 2201 is limited by the first piston rod 2 and the cylinder 1. The cylinder 1 has an oil drain port 23 located between the U-shaped sealing ring 2201 and the first copper sleeve 2202.

[0044] The U-shaped sealing ring 2201 is a redundant design to prevent oil leakage after the first V-shaped sealing ring group 2203 is damaged, providing an extra layer of protection. A retaining ring 2205 is provided at the end of the U-shaped sealing ring 2201 to prevent it from being squeezed out under high pressure. The first V-shaped sealing ring group 2203 serves as the main seal, preventing hydraulic oil from leaking from the rod chamber 6 of the main cylinder. The second copper sleeve 2204 is relatively long, serving as a metal guide. Its long guide support length provides strong support capacity, and the copper sleeve has a certain self-lubricating ability, reducing friction and improving equipment efficiency. Direct contact between the copper sleeve and the piston rod will not damage the piston rod.

[0045] The function of the drain port 23: After long-term use, the reciprocating motion of the first piston rod 2 causes wear and tear on the first V-ring seal group 2203, resulting in seal failure. Hydraulic oil will then enter the drain port 23. During routine maintenance, we can periodically check the drain port 23 for any oil leakage. If oil leakage is found, it indicates that the first V-ring seal group 2203 has failed. However, due to the presence of the subsequent U-ring seal 2201, leakage is unlikely. Simply replacing the first V-ring seal group 2203 will restore normal operation. This structure allows for timely prediction of seal failure and prevents the failure of the first V-ring seal group 2203, which could lead to the failure of the subsequent U-ring seal 2201 and subsequent hydraulic oil leakage, contaminating the work area. Furthermore, since the moving beam 25 is located under a high-temperature forging, hydraulic oil leakage into the forging could pose a fire risk. Therefore, timely prediction and response are crucial.

[0046] Example 5 Based on the above embodiments, this embodiment features a special design for the piston seal. Due to the higher hydraulic pressure, the sealing requirements are higher than those for ordinary hydraulic cylinders. This mainly refers to the seal at the connection between the first piston 4 and the cylinder barrel 1.

[0047] The first piston 4 is connected to the cylinder 1 via the second sealing assembly 24, such as Figure 2 As shown, the second sealing assembly 24 includes a Glyd ring 2401 and a second V-shaped sealing ring assembly 2402. The Glyd ring 2401 is a sealing ring located on the rod-side of the master cylinder. The second V-shaped sealing ring assembly 2402 serves as the main seal. A triangular retaining ring 2403 is located at the outer apex of the side of the second V-shaped sealing ring assembly 2402 facing the Glyd ring 2401. The contact surface between the triangular retaining ring 2403 and the second V-shaped sealing ring assembly 2402 is an inclined surface. Figure 2 As shown, the inclined surface has an angle with the axial direction of the oil cylinder 27. This type of seal can ensure that under a large extrusion gap (i.e., when the gap between the cylinder 1 and the first piston 4 is large), the triangular retaining ring 2403 can be pushed into the gap by the oil pressure on the rod chamber 6 side of the main cylinder. (That is, the second V-shaped sealing ring group 2402 pushes the triangular retaining ring 2403 upward under oil pressure, and the outer circle of the triangular retaining ring 2403 can keep in contact with the inner wall of the cylinder 1, thereby preventing the second V-shaped sealing ring group 2402 from being squeezed out) thus ensuring a good sealing effect.

[0048] like Figure 3As shown, the inner circumference of the Glyd ring 2401 is provided with an elastomer 2404 to increase the clamping effect. The function of the Glyd ring 2401 is to provide a bidirectional seal, that is, to isolate the oil in the front and rear chambers. The oil in the rod chamber 6 of the main cylinder cannot flow to the rodless chamber 7 of the main cylinder, and the oil in the rodless chamber 7 of the main cylinder cannot flow to the rod chamber 6 of the main cylinder. Since the oil in the rodless chamber 7 of the main cylinder on the left side has been separated by the second V-shaped sealing ring group 2402, the Glyd ring 2401 only needs to block the oil in the rod chamber 6 of the main cylinder. Because the pressure in the rod chamber 6 of the main cylinder is also relatively high and the expansion of the cylinder 1 is large, a corner-reinforced retaining ring 2405 is added at the outer corner of the side of the Glyd ring 2401 facing the second V-shaped sealing ring group 2402 to prevent the Glyd ring 2401 from being squeezed out under the large extrusion gap.

[0049] Example 6 A forging system, such as Figure 5 As shown, the machine includes a frame, a worktable 28, a moving beam 25 located above the worktable 28, and the aforementioned large ring forging press cylinder 27. The cylinder barrel 1 of the large ring forging press cylinder 27 is fixed to the frame, the first piston rod 2 passes through the moving beam 25 and is fixed thereto, and the large ring forging press cylinder 27 is located at the center of the moving beam 25.

[0050] In a further design, the open end of the first piston rod 2 is provided with a guide sleeve 26 and a retaining ring 13. The guide sleeve 26 has a guide cylinder 2601 that contacts the outer peripheral surface of the second piston rod 3 and an end cap 2602 that contacts the end face of the first piston rod 2. The retaining ring 13 is clamped on the outer periphery of the first piston rod 2. The end cap 2602 contacts the upper end face of the moving beam 25. The retaining ring 13 is fixed to the moving beam 25 by bolts. The retaining ring 13 is formed by splicing together at least two arc-shaped blocks.

[0051] How is the hydraulic cylinder 27 installed on the equipment: First, the front end face of the guide sleeve 26 contacts the moving beam 25. The moving beam 25 also has a hole drilled in the middle to facilitate the extension and retraction of the first piston rod 2. The retaining ring 13 is connected to the moving beam 25 as a whole by screws. The retaining ring 13 itself is fixed to the first piston rod 2. Therefore, the extension and retraction of the first piston rod 2 can drive the movement of the moving beam 25, and the workpiece to be forged is below the moving beam 25. The cylinder bottom 102 is fixed to the top of the equipment, and the entire hydraulic cylinder 27 is installed vertically downwards. A punch is also connected to the end of the second piston rod 3 to facilitate punching. The piercing cylinder has a built-in displacement sensor 16 to detect the extension displacement of the second piston rod 3 and control the punching depth.

[0052] The specific forging process includes the following steps: S1: Roughening; The rodless chamber 7 of the main cylinder is pressurized, pushing the first piston rod 2 to extend, which in turn drives the moving beam 25 to apply positive pressure to the workpiece.

[0053] S2: Calibration; After the upsetting is completed, control the position of the first piston rod 2 to keep the moving beam 25 in contact with the workpiece.

[0054] S3: Punching; The first piston rod 2 remains stationary, pressurizing the rodless perforation chamber 9, which pushes the second piston rod 3 to extend, performing a punching operation on the workpiece. A top punch is typically installed at the end of the second piston rod 3, extending into the workpiece to perform the punching operation.

[0055] S4: The second piston rod 3 retracts; the first piston rod 2 remains stationary, pressurizing the through rod chamber 8, pushing the second piston rod 3 to retract, and the punch at the end of the second piston rod 3 leaves the workpiece.

[0056] S5: The first piston rod 2 retracts; pressure is applied to the rod chamber 6 of the main cylinder, pushing the first piston rod 2 to retract, and the moving beam 25 is pulled back, separating from the workpiece.

[0057] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0058] In this specification, the illustrative expressions of the terms do not necessarily refer to the same embodiments. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0059] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A hydraulic cylinder for a large ring forging press, characterized in that: It includes a cylinder, a first piston rod located inside the cylinder, and a second piston rod located inside the first piston rod. A first piston is provided between the first piston rod and the cylinder, and a second piston is provided between the second piston rod and the first piston rod. The first piston divides the internal cavity of the cylinder into a rod-side chamber of the main cylinder and a rodless chamber of the main cylinder. Both the cylinder and the first piston rod are closed at one end and open at the other. The second piston divides the internal cavity of the first piston rod into a perforated rod cavity and a perforated rodless cavity. The first piston rod has an axially extending intermediate oil passage. The intermediate oil passage is connected to the outside through a first oil port on the outer surface of the first piston rod and to the perforated rodless cavity through a second oil port on the inner surface of the first piston rod. The perforated rod cavity is connected to a third oil port on the surface of the first piston rod. The first oil port and the third oil port are both located close to the open end of the first piston rod, so that during the reciprocating motion of the first piston rod, the first oil port and the third oil port are always located outside the cylinder.

2. The hydraulic cylinder for a large ring forging press according to claim 1, characterized in that: The first piston rod has a closed hollow cavity inside.

3. The hydraulic cylinder for a large ring forging press according to claim 1, characterized in that: The inner bottom surface of the perforated rodless cavity is provided with an annular retraction groove, which serves as a second oil port and communicates with the oil passage.

4. The hydraulic cylinder for a large ring forging press according to claim 1, characterized in that: A displacement sensor is installed on the inner bottom surface of the first piston rod, which is directly opposite the end of the second piston rod.

5. The hydraulic cylinder for a large ring forging press according to claim 1, characterized in that: The cylinder includes a cylinder body and a cylinder bottom located at one end of the cylinder body. The cylinder bottom is provided with a radial oil passage and an axial oil passage that are interconnected. The radial oil passage extends to the surface of the cylinder bottom to form a fourth oil port. The axial oil passage is located at the center of the cylinder bottom and communicates with the rodless chamber of the main cylinder.

6. The hydraulic cylinder for a large ring forging press according to claim 1, characterized in that: An expansion ring is provided between the radial contact surface of the cylinder body and the bottom of the cylinder, and the radial inner surface of the expansion ring has one or more arc-shaped protrusions spaced apart.

7. The hydraulic cylinder for a large ring forging press according to claim 1, characterized in that: The first piston rod is connected to the cylinder opening end through a first sealing assembly. The first sealing assembly includes a U-shaped sealing ring, a first copper sleeve, a first V-shaped sealing ring group, and a second copper sleeve arranged sequentially along the axial direction. The first copper sleeve and the second copper sleeve abut against both ends of the first V-shaped sealing ring group. The U-shaped sealing ring is limited by the first piston rod and the cylinder. The cylinder has an oil drain port located between the U-shaped sealing ring and the first copper sleeve.

8. The hydraulic cylinder for a large ring forging press according to claim 1, characterized in that: The first piston is connected to the cylinder via a second sealing assembly. The second sealing assembly includes a Glyd ring and a second V-shaped sealing ring group. The Glyd ring is located on the rod chamber side of the master cylinder. The second V-shaped sealing ring group has a triangular retaining ring at the outer apex of the side facing the Glyd ring. The contact surface between the triangular retaining ring and the second V-shaped sealing ring group is an inclined surface. The inner circumference of the Gladius ring is provided with an elastomer, and the outer circumference is provided with a reinforcing retaining ring at the outer corner of the side facing the second V-shaped sealing ring assembly.

9. A forging system, characterized in that: The machine includes a frame, a worktable, a moving beam located above the worktable, and a hydraulic cylinder for a large ring forging press as described in any one of claims 1-8. The cylinder barrel of the hydraulic cylinder for the large ring forging press is fixed to the frame, the first piston rod passes through the moving beam and is fixed thereto, and the hydraulic cylinder for the large ring forging press is located at the center of the moving beam.

10. The forging system according to claim 9, characterized in that: The first piston rod has a guide sleeve and a retaining ring at its open end. The guide sleeve has a guide cylinder that contacts the outer circumferential surface of the second piston rod and an end cap that contacts the end face of the first piston rod. The retaining ring is clamped on the outer circumference of the first piston rod. The end cap contacts the upper end face of the moving beam. The retaining ring is fixed to the moving beam by bolts. The retaining ring is formed by splicing at least two arc-shaped blocks.

11. A forging method, characterized in that, Includes the following steps: S1: Upsetting; The rodless chamber of the main cylinder is pressurized, pushing the first piston rod to extend and driving the moving beam to apply positive pressure to the workpiece; S2: Calibration; After the upsetting is completed, control the position of the first piston rod to keep the moving beam in contact with the workpiece; S3: Punching; The first piston rod remains stationary, pressurizing the rodless cavity for perforation, pushing the second piston rod out to perform punching operation on the workpiece; S4: The second piston rod retracts; the first piston rod remains stationary, pressurizing the rod chamber of the through hole, pushing the second piston rod to retract, and the punch at the end of the second piston rod leaves the workpiece; S5: The first piston rod retracts; pressure is applied to the rod chamber of the main cylinder, pushing the first piston rod to retract, the moving beam is pulled back, and it separates from the workpiece.

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