A large clamp-type hydraulic press

Abstract

This invention relates to the field of hydraulic presses, specifically to a large clamp-type hydraulic press. It includes a hydraulic frame, a hydraulic cylinder, a main oil supply system, a first auxiliary oil supply system, and a second auxiliary oil supply system. The hydraulic cylinder includes a cylinder body, a piston rod body, a main piston, and an auxiliary piston. The cylinder body is mounted on the hydraulic frame, the main piston is slidably disposed inside the cylinder body, and the piston rod body is inserted inside the cylinder body with one end connected to the side of the main piston near the cylinder port. The auxiliary piston is slidably sleeved on the piston rod body and makes slidable contact with the inner wall of the cylinder body. The main oil supply system is used to control the movement of the main piston. The first and second auxiliary oil supply systems are used to control the movement of the auxiliary piston. This invention, through the movement of the auxiliary piston, ensures that even if the hydraulic cylinder does not operate at its full stroke, the oil film on the inner wall of the cylinder body can be fully renewed under the action of the auxiliary piston, thereby improving the service life of the hydraulic cylinder.

Description

Technical Field

[0001] This invention relates to the field of hydraulic presses, and more specifically to a large clamp-type hydraulic press. Background Technology

[0002] A clamp-type hydraulic press is a tool that uses hydraulic principles to perform crimping or clamping operations, and is widely used in power construction, oilfield well repair, and other fields. The oil film on the inner wall of the cylinder of a clamp-type hydraulic press reduces friction, prevents wear, and ensures the stability of energy transmission. It is one of the key factors for the efficient operation of a hydraulic system. During the operation of the internal components of the hydraulic press, the oil film can be continuously renewed to maintain its excellent performance.

[0003] However, since the actual working stroke of a hydraulic press is related to the thickness of the workpiece being pressed, there are non-full-stroke operating conditions. During non-full-stroke conditions, the oil film at the extreme points of the hydraulic cylinder's total stroke cannot be renewed, leading to severe friction and wear. Furthermore, when existing clamp-type hydraulic presses process large workpieces, errors in the pressure application points and the characteristics of the "C"-shaped frame cause the piston rod to be subjected to uneven loads, further resulting in uneven circumferential stress on the piston and cylinder head sealing structure, leading to uneven wear.

[0004] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a large clamp-type hydraulic press to solve the problems of incomplete oil film renewal and off-center wear in existing clamp-type hydraulic presses.

[0006] The present invention provides a large clamp-type hydraulic press with the following technical solution: including:

[0007] Hydraulic frame, the hydraulic frame has a U-shaped slot;

[0008] A hydraulic cylinder is disposed on one side wall of the U-shaped groove of the hydraulic frame, with its output end pointing towards the inner wall of the other side of the U-shaped groove. The hydraulic cylinder includes a cylinder body, a piston rod body, a main piston, and an auxiliary piston. The cylinder body is disposed inside the hydraulic frame. The main piston is slidably disposed inside the cylinder body. The piston rod body is inserted into the cylinder body and one end is connected to the side of the main piston near the cylinder opening of the cylinder body. The auxiliary piston is slidably sleeved on the piston rod body and slidably contacts the inner wall of the cylinder body. The main piston divides the internal space of the cylinder body into a rod chamber and a rodless chamber. The auxiliary piston divides the rod chamber into a first chamber and a second chamber. The first chamber is close to the main piston.

[0009] The main oil supply system is used to supply and discharge oil to the rodless chamber to control the movement of the main piston.

[0010] A first auxiliary oil supply system and a second auxiliary oil supply system, the first auxiliary oil supply system is used to supply and discharge oil to the first chamber and the second auxiliary oil supply system is used to supply and discharge oil to the second chamber, so as to control the movement of the auxiliary piston and thereby renew the oil film on the inner wall of the cylinder body.

[0011] Optionally, the cylinder body includes a cylinder barrel, a front end plate, and a rear end plate. The front end plate and the rear end plate are detachably connected to the cylinder barrel. The front end plate includes a fixed part and a rotating ring. The fixed part is detachably and sealingly connected to the cylinder barrel. The rotating ring is disposed inside the fixed part and sleeved on the piston rod body. The rotating ring can rotate relative to the fixed part and the piston rod body. The main piston is rotatably connected to the piston rod body.

[0012] A transmission structure is provided between the auxiliary piston and the main piston, and between the auxiliary piston and the rotating ring. The transmission structure is configured to convert the movement of the auxiliary piston into the rotation of the main piston and the rotating ring.

[0013] Optionally, the main piston is unidirectionally rotatably connected to the piston rod body, and the rotating ring is unidirectionally rotatably connected to the piston rod body, with the rotation direction of the main piston relative to the piston rod body being opposite to the rotation direction of the rotating ring relative to the piston rod body.

[0014] Optionally, the transmission mechanism includes an elastic push rod and a push block. The elastic push rod is disposed at both ends of the auxiliary piston, and push blocks are disposed on the rotating ring and the end face of the main piston near the auxiliary piston. The elastic push rod is elastic and spirally extended.

[0015] Optionally, multiple elastic push rods are evenly arranged along the circumference of the auxiliary piston, and multiple push blocks are evenly arranged along the circumference of the main piston and the rotating ring, with each elastic push rod corresponding to a push block.

[0016] Optionally, the auxiliary piston includes an outer piston, a middle piston, and an inner piston; the outer piston slides and seals against the inner wall of the cylinder; there is a movable gap between the middle piston and the outer piston, and a third sealing ring is provided at the movable gap, the third sealing ring being configured to seal the middle piston and the outer piston while allowing the middle piston and the outer piston to have a movable allowance; the middle piston and the inner piston are rotatably sealed together; the inner piston is slidably sealed together with the piston rod body.

[0017] Optionally, an elastic push rod is disposed on the outer piston, and an anti-rotation seal is disposed between the outer piston and the inner peripheral wall of the cylinder body. The anti-rotation seal is configured to prevent the outer piston from rotating.

[0018] Optionally, a piston seal ring is provided between the main piston and the cylinder, and the piston seal ring is inclined.

[0019] Optionally, the first auxiliary oil supply system includes a second oil port and a follower oil pipe. The second oil port is located at the tail of the cylinder body, and the follower oil pipe is located in the rodless chamber. One end of the follower oil pipe is connected to the second oil port and the other end is connected to the first chamber. The follower oil pipe is a flexible hose, and the second oil port is connected to the oil supply pump.

[0020] Optionally, the hydraulic frame is equipped with lifting lugs.

[0021] The beneficial effects of the present invention are as follows: A large clamp-type hydraulic press of the present invention provides an auxiliary piston in the rod chamber of the hydraulic cylinder. During the movement of the piston rod body controlled by the main oil supply system, the movement of the auxiliary piston is controlled by the first auxiliary oil supply system and the second auxiliary oil supply system. Even if the hydraulic cylinder does not work at full stroke, the oil film on the inner wall of the cylinder body can be fully renewed under the action of the auxiliary piston, thereby improving the service life of the hydraulic cylinder.

[0022] Furthermore, the front sealing plate of the hydraulic cylinder body is set as a split structure including a fixed part and a rotating ring, so that the rotating ring can rotate. At the same time, the main piston can rotate relative to the piston rod body. When the auxiliary piston moves, the rotating ring and the main piston are controlled to rotate periodically through the transmission structure, so as to transfer the off-center load of the piston rod body to all parts of the circumference and reduce the uneven wear caused by the off-center load.

[0023] Furthermore, by tilting the piston seal ring between the main piston and the cylinder body, the axial coverage area of ​​the piston seal ring on the main piston is increased. When the device is first started after a long period of inactivity, the main piston can be rotated periodically by the auxiliary piston. When the main piston rotates, it drives the piston seal ring to rotate, changing the contact position between the piston seal ring and the inner wall of the cylinder. This can pre-lubricate and pre-renew the oil film at the location of the piston seal ring, reducing the degree of dry friction. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall mechanism of a large clamp-type hydraulic press according to the present invention;

[0026] Figure 2 This is a front view of a large clamp-type hydraulic press according to the present invention;

[0027] Figure 3 This is a side view of a large clamp-type hydraulic press according to the present invention;

[0028] Figure 4 for Figure 3 Sectional view of AA;

[0029] Figure 5 This is an exploded view of a large clamp-type hydraulic press according to the present invention;

[0030] Figure 6 This is a schematic diagram of the hydraulic cylinder in this invention;

[0031] Figure 7 for Figure 6 The front view;

[0032] Figure 8 for Figure 7 BB section view;

[0033] Figure 9 for Figure 8 Enlarged view of point A in the middle;

[0034] Figure 10 for Figure 8 Enlarged view at point B in the middle;

[0035] Figure 11 for Figure 8 Enlarged view at point C;

[0036] Figure 12 This is an exploded view of the hydraulic cylinder in this invention.

[0037] In the picture:

[0038] 100. Hydraulic frame; 101. Lifting lug; 102. Limiting plate; 103. Placement slot;

[0039] 200. Hydraulic cylinder;

[0040] 210. Cylinder body; 2101. First oil hole; 2102. Second oil hole; 2103. Third oil hole; 211. Cylinder barrel; 212. Front sealing plate; 2121. Fixing part; 21211. Second sealing ring; 21212. Rotary sealing ring; 21213. Auxiliary sealing ring; 2122. Rotating ring; 21221. Dustproof ring; 21222. Piston rod sealing ring; 21223. Guide sealing ring one; 21224. One-way bearing two; 213. Rear sealing plate; 2131. First sealing ring; 214. Limiting ring; 215. Pin;

[0041] 220. Piston rod body;

[0042] 230. Main piston; 231. Piston seal ring; 232. Guide seal ring II; 233. One-way bearing I;

[0043] 240. Auxiliary piston; 241. Outer piston; 2411. Sixth sealing ring; 2412. Anti-rotation sealing ring; 242. Middle piston; 2421. Third sealing ring; 2422. Fourth sealing ring; 243. Inner piston; 2431. Fifth sealing ring;

[0044] 250. Follow-up oil pipe;

[0045] 271. Flexible push rod; 272. Push block. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] like Figures 1 to 12 As shown, an embodiment of the present invention provides a large clamp-type hydraulic press including a hydraulic frame 100 and a hydraulic cylinder 200; the hydraulic frame 100 is generally U-shaped, and thus has a U-shaped groove; the hydraulic cylinder 200 is disposed on one side wall of the U-shaped groove of the hydraulic frame 100, and its output end points to the inner wall of the other side of the U-shaped groove. Specifically, refer to... Figure 5 A placement groove 103 is provided inside one side wall of the hydraulic frame 100. The hydraulic cylinder 200 is disposed in the placement groove 103. A removable limiting plate 102 is provided at the opening of the placement groove 103 to prevent the hydraulic cylinder 200 from disengaging from the placement groove 103. During operation, the workpiece to be clamped is placed in the U-shaped groove, and the output end of the hydraulic cylinder 200 extends to clamp the workpiece at the U-shaped groove.

[0048] The hydraulic cylinder 200 includes a cylinder body 210, a piston rod body 220, a main piston 230, and an auxiliary piston 240.

[0049] The cylinder body 210 is disposed in the placement slot 103 inside the hydraulic frame 100, and the main piston 230 is slidably disposed inside the cylinder body 210; the piston rod body 220 is inserted into the cylinder body 210 and one end is connected to the side of the main piston 230 near the cylinder port of the cylinder body 210, and then moves under the drive of the main piston 230 to clamp or release the workpiece; the auxiliary piston 240 is slidably sleeved on the piston rod body 220 and slides in contact with the inner wall of the cylinder body 210. The main piston 230 divides the internal space of the cylinder body 210 into a rod chamber and a rodless chamber, and the auxiliary piston 240 divides the rod chamber into a first chamber and a second chamber, with the first chamber close to the main piston 230.

[0050] The large clamp-type hydraulic press of the present invention also includes a main oil supply system, a first auxiliary oil supply system and a second auxiliary oil supply system. The main oil supply system is used to supply and discharge oil to the rodless chamber to control the movement of the main piston 230. The first auxiliary oil supply system is used to supply and discharge oil to the first chamber and the second auxiliary oil supply system is used to supply and discharge oil to the second chamber to control the movement of the auxiliary piston 240, thereby updating the oil film on the inner wall of the cylinder body 210.

[0051] It is understandable that an oil film is formed on the inner wall of the cylinder body 210 of the hydraulic cylinder 200. The presence of this oil film lubricates the moving parts of the hydraulic cylinder 200, thereby reducing wear and improving operational reliability. During operation, the moving parts of the hydraulic cylinder 200 continuously renew the oil film to ensure its lubricating performance. However, since the actual working stroke of the hydraulic cylinder 200 is related to the thickness of the workpiece to be clamped, the hydraulic cylinder 200 may not operate at its full stroke. In this case, the oil film at the extreme positions of the total stroke cannot be renewed, resulting in more severe friction and wear.

[0052] In this embodiment, during the process of the main oil supply system controlling the piston rod body 220 to extend and clamp the workpiece, the auxiliary piston 240 is moved by the first and second auxiliary oil supply systems to renew the oil film on the inner wall of the cylinder body 210. Specifically, oil is discharged from the first and second chambers simultaneously, with the oil discharge from the second chamber being greater than that from the first chamber, so that the auxiliary piston 240 moves towards the cylinder port position of the cylinder body 210. After the piston rod body 220 clamps the workpiece, the rodless chamber stops supplying oil. At this time, if the auxiliary piston 240... If the cylinder does not reach its limit position, oil is controlled to enter the first chamber and exit the second chamber until the auxiliary piston 240 moves to its limit position. When the piston rod body 220 retracts, the auxiliary piston 240 moves towards the main piston 230 to renew the oil film on the inner wall of the cylinder body 210. Through the setting of the auxiliary piston 240, even if the hydraulic cylinder 200 does not work at full stroke, the oil film on the inner wall of the cylinder body 210 can be fully renewed under the action of the auxiliary piston 240, thereby improving the service life of the hydraulic cylinder 200.

[0053] In a further embodiment, the main oil supply system includes a first oil hole 2101 disposed on the cylinder body 210. The first oil hole 2101 is connected to the rodless chamber and is connected to an oil supply pump through a pipeline to realize the supply and discharge of oil to the rodless chamber.

[0054] The first auxiliary oil supply system includes a second oil port 2102 and a follower oil pipe 250. The second oil port 2102 is located at the rear of the cylinder body 210, and the follower oil pipe 250 is located in the rodless chamber. One end of the follower oil pipe 250 is connected to the second oil port 2102, and the other end is connected to the first chamber. The follower oil pipe 250 is a flexible hose, which can move with the movement of the main piston 230. Specifically, the follower oil pipe 250 can be made of a high-molecular polymer, or it can be shaped by a soft steel wire layer inside a conventional plastic sheath, initially coiled in a spiral shape (see reference). Figure 11 It can be unfolded after being pulled. The second oil hole 2102 is connected to the oil supply pump. Through the setting of the second oil hole 2102 and the follower oil pipe 250, it can adapt to the changes in the space of the first cavity, thereby stably and reliably supplying and discharging oil into the first cavity.

[0055] In order to achieve the connection between the follower oil pipe 250 and the first cavity, one embodiment of the present invention provides an oil passage hole on the main piston 230 that connects to the first cavity, and the follower oil pipe 250 is connected to the oil passage hole.

[0056] Furthermore, multiple oil passages are evenly distributed along the circumference of the main piston 230. A connecting hole is provided on the end face of the main piston 230 near the rodless chamber. The connecting hole is coaxial with the main piston 230, and the oil passages communicate with the connecting hole. An oil supply plate is provided inside the connecting hole, and there is a gap between the oil supply plate and the bottom of the connecting hole to form an oil storage chamber. A central hole is provided at the center of the oil supply plate, which communicates with the oil storage chamber. The follower oil pipe 250 communicates with the central hole. By providing multiple oil passages, the follower oil pipe 250 can supply oil to the first chamber evenly.

[0057] The second auxiliary oil supply system includes a third oil hole 2103, which is located in the cylinder body 210 and connected to the second chamber. The third oil hole 2103 is connected to the oil supply pump to realize the supply and discharge of oil to the second chamber.

[0058] In a further embodiment, for ease of manufacturing and assembly, the cylinder body 210 includes a cylinder barrel 211, a front sealing plate 212 and a rear sealing plate 213. The front sealing plate 212 and the rear sealing plate 213 are detachably connected to the cylinder barrel 211. A second oil hole 2102 is provided on the rear sealing plate 213. A first sealing ring 2131 is provided between the rear sealing plate 213 and the cylinder barrel 211 to achieve sealing between the rear sealing plate 213 and the cylinder barrel 211.

[0059] In a further embodiment, the front sealing plate 212 includes a fixing part 2121 and a rotating ring 2122. The fixing part 2121 is detachably connected to the cylinder barrel 211 of the cylinder body 210. A second sealing ring 21211 is provided between the fixing part 2121 and the cylinder barrel 211 to achieve sealing between the fixing part 2121 and the cylinder barrel 211.

[0060] The rotating ring 2122 is disposed inside the fixed part 2121 and sleeved on the piston rod body 220. The rotating ring 2122 can rotate relative to the fixed part 2121 and the piston rod body 220. The main piston 230 is rotatably connected to the piston rod body 220.

[0061] A transmission structure is provided between the auxiliary piston 240 and the main piston 230, and between the auxiliary piston 240 and the rotating ring 2122. The transmission structure is configured to convert the movement of the auxiliary piston 240 into the rotation of the main piston 230 and the rotating ring 2122.

[0062] In this embodiment, by configuring the rotating ring 2122 of the front sealing plate 212 and the main piston 230 to rotate, the rotating ring 2122 and the main piston 230 are controlled to rotate periodically through a transmission structure when the auxiliary piston 240 moves. This transmits the off-center load of the piston rod body 220 to all parts of the circumference, reducing uneven wear caused by off-center load. It should also be noted that when the aforementioned embodiments of multiple oil supply pipes are applied to this embodiment, the oil supply plate rotates relative to the main piston 230 and is rotary sealed, thereby preventing the follow-up oil pipe 250 from twisting.

[0063] Furthermore, refer to Figure 9 As shown, a limit ring 214 is provided at the front end of the front cover plate 212. The limit ring 214 is detachably connected to the fixing part 2121 of the front cover plate 212 by a pin 215. The limit ring 214 cooperates with the stop of the rotating ring 2122 to limit the axial position of the rotating ring 2122.

[0064] A dustproof ring 21221, a piston rod sealing ring 21222, and a guide sealing ring 21223 are sequentially arranged between the rotating ring 2122 and the piston rod body 220 from the cylinder port to the cylinder tail. The dustproof ring 21221 can prevent external dust, impurities, and moisture from entering the cylinder body 210, protecting the internal structure of the cylinder body 210 from contamination and ensuring the normal operation of the hydraulic cylinder 200. The piston rod sealing ring 21222 is the main sealing component of the piston rod body 220 and can effectively prevent hydraulic oil leakage. The guide sealing ring 21223 can support the piston rod body 220, guide linear movement, and avoid metal-to-metal contact.

[0065] A rotary sealing ring 21212 is provided between the rotating ring 2122 and the fixed part 2121 to achieve rotational sealing between the rotating ring 2122 and the fixed part 2121. Auxiliary sealing rings 21213 are provided on both sides of the rotary sealing ring 21212 to enhance the sealing between the rotating ring 2122 and the fixed part 2121.

[0066] Reference Figure 11A piston seal ring 231 is provided between the main piston 230 and the cylinder 211. The piston seal ring 231 can be a rotary seal to achieve rotational sealing between the main piston 230 and the cylinder 211. Guide sealing rings 232 are provided on both sides of the piston seal ring 231. The guide sealing rings 232 can support the rod of the main piston 230, guide linear movement, and avoid metal-to-metal contact.

[0067] In a further embodiment, the main piston 230 is unidirectionally rotatably connected to the piston rod body 220, and the rotating ring 2122 is unidirectionally rotatably connected to the piston rod body 220. The rotation direction of the main piston 230 relative to the piston rod body 220 is opposite to the rotation direction of the rotating ring 2122 relative to the piston rod body 220.

[0068] Specifically, a one-way bearing 233 is provided between the main piston 230 and the piston rod body 220. The one-way bearing 233 is configured such that the main piston 230 can only rotate in a first direction relative to the piston rod body 220. A one-way bearing 21224 is provided between the rotating ring 2122 and the piston rod body 220. The one-way bearing 21224 is configured such that the rotating ring 2122 can only rotate in a second direction relative to the piston rod body 220.

[0069] By setting the main piston 230 and the rotating ring 2122 to rotate in one direction with different directions of rotation, the rotating ring 2122 can restrict the rotation of the piston rod body 220 when the main piston 230 rotates, making the rotation of the main piston 230 more reliable. When the rotating ring 2122 rotates, the main piston 230 can restrict the rotation of the piston rod body 220, thereby making the rotation of the rotating ring 2122 more reliable, thus improving the operational stability of the device.

[0070] In a further embodiment, the transmission mechanism includes an elastic push rod 271 and a push block 272. The elastic push rod 271 is disposed at both ends of the auxiliary piston 240, and the rotating ring 2122 and the end face of the main piston 230 near the auxiliary piston 240 are both provided with push blocks 272. The elastic push rod 271 is elastic and spirally extended.

[0071] In this embodiment, when the auxiliary piston 240 moves until the elastic push rod 271 contacts the rotating ring 2122 or the main piston 230, as the auxiliary piston 240 continues to move, the elastic push rod 271 is compressed and gradually comes into contact with the push block 272. After the elastic push rod 271 comes into contact with the push block 272, it continues to compress under the movement of the auxiliary piston 240 and pushes the rotating ring 2122 or the main piston 230 to rotate through the push block 272. The rotation of the rotating ring 2122 and the main piston 230 can transfer the off-center load of the piston rod body 220 to all parts of the circumference, reducing the uneven wear caused by the off-center load.

[0072] In a further embodiment, multiple elastic push rods 271 are evenly arranged along the circumferential direction of the auxiliary piston 240, and multiple push blocks 272 are evenly arranged along the circumferential direction of the main piston 230 and the rotating ring 2122, with each elastic push rod 271 corresponding to a push block 272.

[0073] In this embodiment, by setting multiple elastic push rods 271 and push blocks 272, the transmission of motion is made more reliable and smooth, thereby improving the stability and accuracy of equipment operation.

[0074] In a further embodiment, refer to Figure 10 The auxiliary piston 240 includes an outer piston 241, a middle piston 242, and an inner piston 243.

[0075] The outer piston 241 slides and seals against the inner wall of the cylinder 211; there is a movable gap between the middle piston 242 and the outer piston 241, and a third sealing ring 2421 is provided at the movable gap. The third sealing ring 2421 is configured to seal the middle piston 242 and the outer piston 241, while allowing the middle piston 242 and the outer piston 241 to have a movable allowance; the middle piston 242 and the inner piston 243 are rotatably and sealingly connected; the inner piston 243 is slidably and sealingly connected to the piston rod body 220.

[0076] In this embodiment, by setting the auxiliary piston 240 as a split structure, when the piston rod body 220 is under eccentric load, the piston rod body 220 drives the inner piston 243 to rotate relative to the middle piston 242. The inner piston 243 pushes the middle piston 242, causing the middle piston 242 to move relative to the outer piston 241. Because there is a clearance between the middle piston 242 and the outer piston 241, the middle piston 242 has a certain amount of movement allowance, so its movement does not affect the contact between the outer piston 241 and the inner wall of the cylinder 211. This ensures the coaxiality of the auxiliary piston 240 and the cylinder body 210, avoids uneven wear of the auxiliary piston 240 when the piston rod body 220 is under eccentric load, and improves the service life of the auxiliary piston 240.

[0077] Furthermore, refer to Figure 10 The outer piston 241 has a mating groove on its surface near the middle piston 242, and the middle piston 242 has a mating protrusion on its surface near the outer piston 241. The width of the mating protrusion is smaller than the width of the mating groove, and the part of the mating protrusion extends into the mating groove. The third sealing ring 2421 is disposed on both sides of the mating protrusion to seal the outer piston 241 and the middle piston 242.

[0078] The surface of the middle piston 242 near the inner piston 243 is a concave arc surface, and the surface of the inner piston 243 near the middle piston 242 is a convex arc surface. The concave and convex arc surfaces are matched to make the middle piston 242 and the inner piston 243 arc-fitted, thereby realizing the rotational fit between the middle piston 242 and the inner piston 243 and ensuring that there is a rotational margin between them. A fourth sealing ring 2422 is provided between the middle piston 242 and the inner piston 243 to ensure the seal between the middle piston 242 and the inner piston 243.

[0079] A fifth sealing ring 2431 is provided between the inner piston 243 and the piston rod body 220 to achieve sliding sealing between the inner piston 243 and the piston rod body 220.

[0080] Furthermore, a sixth sealing ring 2411 is provided between the outer piston 241 and the cylinder 211 to achieve sliding sealing between the outer piston 241 and the cylinder 211.

[0081] A flexible push rod 271 is disposed on the outer piston 241. An anti-rotation seal ring 2412 is also disposed between the outer piston 241 and the inner peripheral wall of the cylinder body 210. The anti-rotation seal ring 2412 is configured to prevent the outer piston 241 from rotating, ensuring that the outer piston 241 can reliably push the main piston 230 and the rotating ring 2122 to rotate via the flexible push rod 271. (Refer to...) Figure 12 As shown, the anti-rotation seal 2412 can be configured with a toothed structure to increase the circumferential frictional resistance with the outer piston 241, thereby hindering the rotation of the outer piston 241.

[0082] In a further embodiment, the piston seal ring 231 is inclinedly disposed on the main piston 230, thereby increasing the axial coverage area of ​​the piston seal ring 231 over the main piston 230. It is understandable that if the device is not used for a long time, the lubricating oil at the location of the piston seal ring 231, after prolonged static compression, is prone to oxidation, gelation, corrosion, and other adverse conditions. When the equipment restarts, this can easily cause dry friction, and the deteriorated oil film and corrosive substances may be carried into the main working area, scratching the mating surfaces and reducing the service life of the equipment.

[0083] In this embodiment, by tilting the piston seal ring 231, when the device is first turned on after a long period of inactivity, the auxiliary piston 240 can be pre-controlled to cause the main piston 230 to rotate periodically. When the main piston 230 rotates, it drives the piston seal ring 231 to rotate, changing the contact position between the piston seal ring 231 and the inner wall of the cylinder 211. This can pre-renew and pre-lubricate the oil film at the location of the piston seal ring 231, reducing the degree of dry friction.

[0084] In other embodiments, the dustproof ring 21221, piston rod sealing ring 21222, fifth sealing ring 2431, sixth sealing ring 2411, etc., can be set to be inclined according to actual usage requirements to reduce the occurrence of dry friction.

[0085] In a further embodiment, refer to Figure 1 and Figure 5 As shown, the hydraulic frame 100 is equipped with lifting lugs 101 to facilitate the hoisting of the hydraulic frame 100.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A large clamp-type hydraulic press, characterized in that, include: Hydraulic frame, the hydraulic frame has a U-shaped slot; A hydraulic cylinder is disposed on one side wall of the U-shaped groove of the hydraulic frame, with its output end pointing towards the inner wall of the other side of the U-shaped groove. The hydraulic cylinder includes a cylinder body, a piston rod body, a main piston, and an auxiliary piston. The cylinder body is disposed inside the hydraulic frame. The main piston is slidably disposed inside the cylinder body. The piston rod body is inserted into the cylinder body and one end is connected to the side of the main piston near the cylinder opening of the cylinder body. The auxiliary piston is slidably sleeved on the piston rod body and slides in contact with the inner wall of the cylinder body. The main piston divides the internal space of the cylinder body into a rod chamber and a rodless chamber. The auxiliary piston divides the rod chamber into a first chamber and a second chamber. The first chamber is close to the main piston. The main oil supply system is used to supply and discharge oil to the rodless chamber to control the movement of the main piston. The first auxiliary oil supply system and the second auxiliary oil supply system are used to supply and discharge oil to the first chamber and to supply and discharge oil to the second chamber, so as to control the movement of the auxiliary piston and thereby renew the oil film on the inner wall of the cylinder body. The cylinder body includes a cylinder barrel, a front end plate, and a rear end plate. The front end plate and the rear end plate are detachably connected to the cylinder barrel. The front end plate includes a fixed part and a rotating ring. The fixed part is detachably and sealingly connected to the cylinder barrel. The rotating ring is disposed inside the fixed part and sleeved on the piston rod body. The rotating ring can rotate relative to the fixed part and the piston rod body. The main piston is rotatably connected to the piston rod body. A transmission structure is provided between the auxiliary piston and the main piston, and between the auxiliary piston and the rotating ring. The transmission structure is configured to convert the movement of the auxiliary piston into the rotation of the main piston and the rotating ring. The auxiliary piston includes an outer piston, a middle piston, and an inner piston; the outer piston slides and seals against the inner wall of the cylinder; there is a movable gap between the middle piston and the outer piston, and a third sealing ring is provided at the movable gap. The third sealing ring is configured to seal the middle piston and the outer piston, while allowing the middle piston and the outer piston to have a movable margin; the middle piston and the inner piston are rotatably sealed together; the inner piston is slidably sealed together with the piston rod body.

2. A large clamp-type hydraulic press according to claim 1, characterized in that, The main piston is unidirectionally connected to the piston rod body, and the rotating ring is unidirectionally connected to the piston rod body. The rotation direction of the main piston relative to the piston rod body is opposite to the rotation direction of the rotating ring relative to the piston rod body.

3. A large clamp-type hydraulic press according to claim 2, characterized in that, The transmission mechanism includes an elastic push rod and push blocks. The elastic push rod is located at both ends of the auxiliary piston, and push blocks are provided on the rotating ring and the end face of the main piston near the auxiliary piston. The elastic push rod is elastic and spirally extended.

4. A large clamp-type hydraulic press according to claim 3, characterized in that, Multiple elastic push rods are evenly arranged along the circumference of the auxiliary piston, and multiple push blocks are evenly arranged along the circumference of the main piston and the rotating ring. Each elastic push rod corresponds to one push block.

5. A large clamp-type hydraulic press according to claim 3, characterized in that, An elastic push rod is provided on the outer piston, and an anti-rotation seal is provided between the outer piston and the inner peripheral wall of the cylinder body. The anti-rotation seal is configured to prevent the outer piston from rotating.

6. A large clamp-type hydraulic press according to claim 1, characterized in that, The first auxiliary oil supply system includes a second oil port and a follower oil pipe. The second oil port is located at the tail of the cylinder body, and the follower oil pipe is located in the rodless chamber. One end of the follower oil pipe is connected to the second oil port and the other end is connected to the first chamber. The follower oil pipe is a flexible hose, and the second oil port is connected to the oil supply pump.

7. A large clamp-type hydraulic press according to claim 1, characterized in that, The hydraulic frame is equipped with lifting lugs.

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