A static seal locking mold hydraulic cylinder for injection molding, die casting machine

Abstract

The utility model discloses a kind of static sealing lock mould hydraulic cylinders for injection molding, die casting machine, be applied to injection molding machine and the equipment such as die casting need lock mould, high-pressure-resistant sealing ring or extrusion type or lip type sealing ring is arranged between lock mould hydraulic cylinder cylinder body and piston, low-pressure liquid can be injected in cylinder body to open and close mould, sealing ring is low-pressure dynamic sealing state in this process, or use external force to open and close mould with liquid tank and liquid filling valve to make cylinder body be filled with liquid, after mould closing is completed, cylinder body and piston are relatively static, high-pressure liquid is injected in cylinder body to complete static sealing lock mould, due to the same structure of static sealing and dynamic sealing pressure difference 5 times or more, durability is 10 times or more, so that sealing element can work stably and durably under high pressure and superhigh pressure conditions.

Description

Technical Field

[0001] This invention relates to a mold-locking hydraulic cylinder, specifically a static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines. Background Technology

[0002] Hydraulic cylinder drives are widely used in injection molding and die casting machines. The national standard for hydraulic cylinders stipulates that the piston rod should not leak after 50,000 strokes. However, injection molding and die casting machines have a very high production cycle, often exceeding 5,000 opening and closing cycles per day. Therefore, the durability and stability requirements are much higher than the national standard of 50,000 cycles. Despite the rapid development of hydraulic sealing technology, the hydraulic system pressure of injection molding and die casting machines has remained difficult to increase. The mainstream die casting machine system pressure is generally 16 MPa, while Haitian's latest generation die casting machine has a hydraulic system pressure of 19 MPa. Based on a pressure of 19 MPa, if a direct-pressure hydraulic cylinder is used for mold clamping, the clamping force is calculated based on the product's projected area and an injection pressure of 50-80 MPa, which is equivalent to 0.5-0.8 tons of clamping force per square centimeter. This means the cylinder area is more than four times the product's projected area. The cross-sectional area of ​​the hydraulic cylinder is too large, making it unsuitable for three-platen machines. Currently, three-platen machines generally use a hinged clamping mechanism. Because two-platen machines use four hydraulic cylinders installed at the four corners of the fixed template, space is not limited. Therefore, direct pressure is generally used on two-platen machines, requiring a hydraulic cylinder capable of operating stably at a pressure of over 50 MPa to complete the direct-pressure clamping. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines, which effectively overcomes the shortcomings of existing technologies.

[0004] This invention is achieved through the following technical solution: a static sealing mold-locking hydraulic cylinder for injection molding and die casting machines, wherein the load-bearing frame is mounted on the machine frame or the head plate and tail plate are directly mounted on the machine frame, the machine frame or tie rod has guide rails and head and tail plates, the head and tail plates and tie rods form the load-bearing frame, there is a middle plate in the middle, the middle plate is mounted on the guide rail, the cylinder body and piston of the hydraulic cylinder are connected to the tail plate and the middle plate respectively or installed in reverse, there is a high pressure resistant sealing ring or extrusion type or lip type sealing ring between the cylinder body and the piston, and there are low pressure and high pressure liquid inlets. When the mold is opened and closed, it is driven by low pressure liquid. After the mold is closed, when the cylinder body and piston are in a relatively static state, high pressure or ultra-high pressure liquid is input to complete the static sealing mold locking.

[0005] As a preferred technical solution, a compression-type sealing ring is added with a retaining ring or a slip ring.

[0006] As a preferred technical solution, the high-pressure resistant sealing ring is a V-shaped combination sealing ring or a drum-shaped combination sealing ring.

[0007] This invention discloses a static sealing mold-locking hydraulic cylinder for injection molding and die casting machines. It comprises a load-bearing frame consisting of head and tail plates and tie rods, which is mounted on the machine frame, or the head and tail plates are directly mounted on the machine frame. Guide rails and head and tail plates are mounted on the machine frame or tie rods, and a middle plate is mounted on the guide rails. A cylinder body and a piston of a mother cylinder are respectively mounted on the tail plate and middle plate. A high-pressure resistant sealing ring, a compression type, or a lip-type sealing ring is located between the cylinder body and the piston. Mold opening and closing are accomplished by the piston being driven by the liquid supplied from the mother cylinder. A liquid tank is connected to the cylinder body or the mother cylinder piston via a filling valve, filling the cylinder body with liquid. After mold closing, the filling valve is closed, and the cylinder body and the mother cylinder piston are in a relatively static state. High-pressure or ultra-high-pressure liquid is injected into the mother cylinder to complete the static sealing mold-locking.

[0008] As a preferred technical solution, a compression-type sealing ring is added with a retaining ring or a slip ring.

[0009] As a preferred technical solution, the high-pressure resistant sealing ring is a V-shaped combination sealing ring or a drum-shaped combination sealing ring.

[0010] This invention discloses a static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines. It comprises a load-bearing frame consisting of head and tail plates and a tie rod. The load-bearing frame is mounted on the machine frame, or the head and tail plates are directly mounted on the machine frame. Guide rails and head and tail plates are mounted on the machine frame or tie rods. A middle plate is mounted on a movable guide rail and is driven by a middle plate drive device to move the middle plate for mold opening and closing. A single-acting hydraulic cylinder is located between the tail plate and the middle plate. After mold closing, a gap exists between the piston and the middle plate, which is filled by a mold-directing moving block. The mold-directing moving block has a drive device that can push or push it out of the machine to open the mold after mold closing. The driving direction is the same as the mold closing direction. The vertical mold-moving block has an inclined surface, which can be set on the middle plate or piston. There is a high-pressure resistant sealing ring, extrusion type or lip type sealing ring between the cylinder and the piston. When the piston end and the tail plate are opposite, the bottom of the cylinder is set with a corresponding inclined surface. After the middle plate drive device drives the middle plate to close the mold, the mold-moving block is driven by the drive device to fill the space between the single-acting hydraulic cylinder and the middle plate. Due to the effect of the inclined surface, the cylinder, piston, middle plate and stationary mold are pressed between the head and tail plates. The cylinder and piston are relatively stationary. High pressure or ultra-high pressure liquid is injected into the inlet to complete the static sealing and mold locking.

[0011] As a preferred technical solution, a compression-type sealing ring is added with a retaining ring or a slip ring.

[0012] As a preferred technical solution, the high-pressure resistant sealing ring is a V-shaped combination sealing ring or a drum-shaped combination sealing ring.

[0013] This invention discloses a static sealing mold-locking hydraulic cylinder for injection molding and die casting machines. It comprises a load-bearing frame consisting of head and tail plates and tie rods. The load-bearing frame is mounted on the machine frame, or the head and tail plates are directly mounted on the machine frame. Guide rails and head and tail plates are mounted on the machine frame or tie rods. A middle plate is mounted on a moving guide rail and is driven by a middle plate drive device to open and close the mold. The cylinder body and piston are connected to or reversed to the tail plate and middle plate, respectively. A high-pressure resistant sealing ring, a compression type, or a lip-type sealing ring is provided between the cylinder body and piston. When the middle plate drive device moves the middle plate, a liquid tank is connected to the cylinder body or piston through a filling valve, filling the cylinder body with liquid. After mold closing, the filling valve is closed, at which point the cylinder body and piston are relatively stationary. High-pressure or ultra-high-pressure liquid is injected into the cylinder body through the cylinder body or piston to complete the static sealing mold-locking.

[0014] As a preferred technical solution, a compression-type sealing ring is added with a retaining ring or a slip ring.

[0015] As a preferred technical solution, the high-pressure resistant sealing ring is a V-shaped combination sealing ring or a drum-shaped combination sealing ring.

[0016] The present invention discloses a static sealing mold-locking hydraulic cylinder for injection molding and die casting machines, comprising a two-platen mechanism, a positioning plate, and a moving plate. The moving plate is mounted on a guide rail and is driven by a drive mechanism. A brake device is provided to brake after mold closing. The invention is characterized in that: a high-pressure resistant sealing ring, a compression type, or a lip type sealing ring is provided between the mold-locking hydraulic cylinder, the cylinder body, and the piston. After brake closing, low-pressure liquid is injected to cause the fixed and moving mold plates to move together, while the brake mechanism and the end face of the moving mold plate are pressed together. Then, high-pressure or ultra-high-pressure liquid is injected to complete the static sealing mold locking.

[0017] As a preferred technical solution, a compression-type sealing ring is added with a retaining ring or a slip ring.

[0018] As a preferred technical solution, the high-pressure resistant sealing ring is a V-shaped combination sealing ring or a drum-shaped combination sealing ring.

[0019] The beneficial effects of this invention are as follows: This invention sets a compression seal ring or a lip seal ring between the cylinder body and the piston of the mold-locking hydraulic cylinder. Low-pressure liquid can be injected into the cylinder body to open and close the mold. During this process, the seal ring is in a low-pressure dynamic sealing state. Alternatively, external force can be used to open and close the mold using a liquid tank and a filling valve to fill the cylinder body with liquid. After the mold is closed, the cylinder body and the piston are relatively stationary. High-pressure liquid is injected into the cylinder body to complete the static sealing and mold locking. Since the static seal and dynamic seal of the same structure have a pressure resistance difference of more than 5 times and a durability difference of more than 10 times, the sealing component can work stably and durablely under high pressure and ultra-high pressure conditions. Attached Figure Description

[0020] 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.

[0021] Figure 1 is a diagram showing the state of the compression seal of the present invention; Figure 2 This is a diagram showing the mold opening state of the direct-drive opening and closing mold locking application of the present invention; Figure 3 This is a diagram showing the mold closing and locking states of the direct-drive mold opening and closing application of the present invention; Figure 4 This is a diagram showing the mold opening state of the pressure transmission block with lateral movement according to the present invention. Figure 5 This is a diagram showing the mold closing and locking states of the pressure transmission block with lateral movement according to the present invention. Figure 6 This is a diagram showing the mold opening state of the direct-drive opening and closing mold locking application of the mother-daughter cylinder structure of the present invention. Figure 7 This is a diagram showing the mold closing and locking states of the direct-drive opening and closing mold-locking application of the mother-daughter cylinder structure of the present invention. Figure 8 This is a diagram showing the mold opening state of the combined application of the mold opening / closing cylinder and the mold locking cylinder of the present invention. Figure 9 This invention provides a diagram illustrating the mold closing and locking states of a combined mold opening and closing cylinder and a mold locking cylinder. Figure 10 This is a diagram showing the state of the two-plate motor after applying the brake according to the present invention; Figure 11 This is a diagram showing the mold closing and locking state after applying the brake to the two-platen machine of the present invention. Figure 12 This is a schematic diagram of an O-ring being installed on the piston of the present invention; Figure 13 A schematic diagram showing the installation of an O-ring and a retaining ring on the piston of this invention; Figure 14 This is a schematic diagram of the present invention or of the lip seal ring being mounted on top; Figure 15 This is a schematic diagram of an O-ring being installed on the piston of the present invention; Figure 16 This is a schematic diagram of an O-ring being installed on the inner bore of the cylinder body according to the present invention; Figure 17 A schematic diagram of installing an O-ring and a retaining ring on the inner bore of the cylinder body according to the present invention; Figure 18 A schematic diagram of the lip seal ring installed on the inner bore of the cylinder body according to the present invention; Figure 19 A schematic diagram showing the installation of an O-ring and sliding ring in the inner bore of the cylinder of the present invention; Figure 20 This is a schematic diagram showing the installation of O-rings and retaining rings on the piston and piston rod of the two-platen machine's locking cylinder according to the present invention; Figure 21 This is a diagram showing the relationship between the internal pressure of the mold-locking cylinder and the relative displacement of the piston in this invention.

[0022] Attached icon descriptions: 1. Head plate; 2. Tail plate; 3. Tie rod; 4. Fixed mold; 5. Moving mold; 6. Middle plate; 7. Cylinder body; 8. Piston rod; 9. Piston rod seal diagram; 10. Piston; 11. Piston seal ring; 12. Mold opening oil inlet; 13. Mold closing oil inlet; 14. Mold locking oil inlet; 15. Single-acting cylinder body; 16. Single-acting cylinder piston seal ring; 17. Single-acting cylinder piston; 171. Inclined surface; 18. Single-acting cylinder inlet / outlet; 19. Mold direction moving block; 1 91. Inclined surface; 20. Mother and daughter cylinder body; 21. Mother and daughter cylinder piston; 22. Inlet and outlet oil pipes of the small cylinder in the mother and daughter cylinder; 23. Mother and daughter cylinder piston sealing ring; 24. Mother and daughter cylinder return oil inlet; 25. Mother and daughter cylinder high-pressure oil inlet; 26. Filling valve inlet and outlet; 27. Passive mold locking cylinder piston sealing ring; 28. Passive mold locking cylinder body; 29. ​​Passive mold locking cylinder piston; 30. Passive mold locking cylinder high-pressure oil inlet; 31. Passive mold locking cylinder filling valve inlet and outlet; 32. Opening and closing mold 33. Mold opening oil inlet; 34. Mold opening and closing oil cylinder piston rod; 35. Mold opening and closing oil cylinder piston; 36. Mold closing oil inlet; 37. Mold opening and closing oil cylinder body; 38. Two-platen machine fixed template; 39. Two-platen machine moving template; 40. Two-platen machine closing and locking oil cylinder; 41. Low-pressure oil inlet; 42. Mold opening oil inlet; 43. Two-platen machine piston; 44. Two-platen machine piston seal ring; 45. Two-platen machine piston rod; 46. High-pressure oil inlet; 47. Two-platen machine piston rod 47. Sealing ring; 48. Two-plate brake device; 49. Cylinder body; 40. Piston for installing sealing ring; 4901. Sealing ring groove; 4902. Sealing ring assembly shoulder; 4903. Sealing ring cover; 4904. Sealing ring cover fixing screw; 50. O-ring seal; 51. Retaining ring; 52. Lip seal; 53. Slip ring (hole contact); 54. Piston without sealing ring; 55. Cylinder body for installing sealing ring; 56. Sealing ring positioning end plate; 57. Slip ring (shaft contact). Detailed Implementation All features disclosed in this specification, or steps in all methods or processes disclosed herein, may be combined in any way, except for mutually exclusive features and / or steps.

[0023] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features for a similar purpose, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0024] Example 1 like Figure 1a The figures b, c, and d represent the four states of liquid pressure experienced by the O-ring seal when sealing between the cylinder and piston. Figure 1a It is in a zero-pressure state. Figure 1b It is in a low-pressure state. Figure 1c It is in a medium pressure state. Figure 1d Under high pressure, the sealing ring is subjected to pressure from the high-pressure liquid, which then presses the sealing ring tightly against the piston rod or cylinder. When the piston rod and cylinder move relative to each other, the sealing ring is subjected to friction, causing damage to the sealing ring. When there is no relative movement between the cylinder and the piston, the sealing ring can withstand greater pressure. For the same structure, the static seal of the O-ring can withstand 5 times more pressure and has a lifespan of more than 10 times that of the dynamic seal. This is the biggest difference between static and dynamic seals.

[0025] like Figure 2 The diagram shows a three-plate die-casting or injection molding structure. The head plate 1, tail plate 2, and tie rod 3 form a load-bearing frame, which is mounted on the machine frame (not shown in the diagram). Some smaller tonnage three-plate machines do not use tie rod 3; instead, the head plate 1 and tail plate 2 are directly mounted and fixed to the machine frame. The middle plate 6 can move on a track (not shown in the diagram). The fixed mold 4 is mounted on the head plate 1, and the moving mold 5 is mounted on the middle plate 6. A direct-pressure hydraulic device, consisting of a cylinder body 7, piston rod 8, and piston 10, is located between the tail plate 2 and the middle plate 6. A piston rod seal is located between the piston rod 8 and the cylinder body 7. Figure 9 There is a piston seal ring 11 between the piston 10 and the cylinder body 7. The cylinder body 7 also has an opening oil inlet 12, a closing oil inlet 13, and a locking oil inlet 14. Figure 2 The mold is in the open state with the fixed mold and moving mold open. Low-pressure liquid (e.g., 15 MPa) is introduced through the mold closing oil inlet 13 to drive pistons 10 and 10, which move the fixed mold 4, moving mold 5, and middle plate 6 and close the mold. Figure 3 In the mold-closed state, after mold closure, high-pressure liquid (e.g., 63 MPa) is introduced through the mold-locking oil inlet 14, causing the drive piston 10 to drive the middle plate 6 via the piston rod 8 to lock the moving mold 5 and the fixed mold 4, completing the static sealing mold-locking. Figure 2 and Figure 3 The cylinder body 7, piston 10, and piston seal ring 11 are three parts directly related to the static seal. The seal ring is a compression seal ring or a lip seal ring 52, and can have various cross-sectional shapes. Figure 12 It is a common O-ring 50. Figure 13Add a retaining ring 51 to the O-ring 50. Figure 12 The piston 49 in the middle has a sealing ring groove 4901 for assembling the sealing ring. Figure 13 The retaining ring 51 and the piston 49 for mounting the sealing ring have sealing ring mounting shoulders 4902. After the O-ring 50 and the retaining ring 51 are installed on the sealing ring mounting shoulders 4902, the sealing ring cover 4903 is covered and then the sealing ring cover fixing screws 4904 are used to fix it. Figure 14 It is a U-shaped sealing ring. Figure 15 Adding a slip ring (hole contact) 53 to an O-ring can improve wear resistance under low pressure. Extrusion-type O-rings come in many cross-sectional shapes. Figure 12 It is a commonly used O-ring cross section, but rectangular, D-shaped, triangular, heart-shaped, square, or dumbbell-shaped sealing rings can also be used to replace O-rings 50. Figure 13 A retaining ring 51 has been added, which greatly improves the static sealing effect. Figure 15 Adding a slip ring 53 can improve the wear resistance of the seal. Alternatively, a retaining ring 51 and a slip ring 53 can be added simultaneously. Figures 16 to 19 The effect of installing sealing rings inside the 48 holes of the cylinder block and Figures 12-15 Yes, they are consistent. In specific designs, both hole sealing rings and shaft sealing rings can be used. Figure 21 This is a schematic diagram of the relationship between the pressure inside the mold-locking cylinder and the relative displacement of the piston in a test of a 630-ton die-casting machine. When the pressure inside the mold-locking cylinder is 0-5 MPa, the piston displacement is 0.25 mm. When the pressure increases from 5 MPa to 15 MPa, the piston 10 moves 0.05 mm relative to the cylinder body. When the pressure inside the cylinder increases from 15 MPa to 63 MPa, the displacement of the piston 10 relative to the cylinder body 48 is only 0.02 mm. This curve will also change depending on the rigidity of the overall frame. In order to further improve the life of the seals and reduce the impact of the displacement between the piston and the cylinder body on the life of the seal ring after the seals are subjected to high pressure, the method of slow cylinder pressurization or distributed pressurization can be adopted to adapt to machines with poor frame rigidity. In this embodiment, the cylinder body can also be connected to the middle plate 6, and the piston rod 8 can be connected to the tail plate 2 to achieve the same goal.

[0026] Example 2 like Figure 4 and Figure 5 As shown, unlike Example 1, the middle plate 6 and the moving mold 5 are not opened and closed by hydraulic cylinders. Figure 4 It is in the mold open state. Figure 5 The moving mold 5 and the fixed mold 4 are in the closed state. A single-acting cylinder is formed by a single-acting cylinder body 15 and a single-acting cylinder piston 17. A single-acting cylinder piston seal ring 16 is located between the single-acting cylinder body 15 and the single-acting cylinder piston 17. The single-acting cylinder body 15 also has a single-acting cylinder inlet / outlet port 18. Furthermore, the mold-moving block 19 can be inserted from the side between the single-acting cylinder piston 17 and the middle plate 6. The insertion and withdrawal directions are as follows: Figure 4 As shown by the middle arrow, the single-acting cylinder piston 17 has an inclined surface 171, and the mold-directing moving block 19 has an inclined surface 191. When the mold-directing moving block 19 is inserted, the two inclined surfaces are pressed together. After the mold-directing moving block 19 is inserted, high-pressure liquid (e.g., 63 MPa) is injected into the single-acting cylinder body 15 from the single-acting cylinder inlet / outlet 18 to drive the single-acting cylinder piston 17 to lock the mold-directing moving block 19, the fixed mold 4, the moving mold 5, and the middle plate 6, thus completing the static sealing and mold locking. In this embodiment, the mold-directing moving block 19 and the corresponding middle plate 6 can also have inclined surfaces, or the single-acting cylinder can be installed in reverse, that is, the piston 10 and the tail plate 2 are in contact, the cylinder body 48 and the mold-directing moving block 19 are in contact, and the contact surfaces of the cylinder body 48 and the mold-directing moving block 19 have inclined surfaces. All of these can achieve the same purpose.

[0027] Example 3 Unlike the above embodiments, the middle plate 6 drives the mold opening and closing, and the mold locking is accomplished by a master cylinder. The master cylinder consists of a master cylinder body 20, a master cylinder piston 21, and a master cylinder small cylinder inlet / outlet oil pipe 22. There is a master cylinder piston sealing ring 23 between the master cylinder body 20 and the master cylinder piston 21. Each part of the master cylinder piston 21 has a hole in the middle, and the master cylinder small cylinder inlet / outlet oil pipe 22 is inserted into the hole. Figure 6 In the open mold state, low-pressure liquid (e.g., 15 MPa) is injected into the middle hole of the oil inlet / outlet pipe 22 of the small cylinder of the mother and daughter cylinders, driving the piston 21 of the mother and daughter cylinders, which in turn moves the middle plate 6 and the moving mold 5 rapidly. At this time, the oil inlet / outlet port 26 of the filling valve connects the filling valve and the liquid tank (the filling valve and the connected liquid tank are industry-known standard configurations, and their structure will not be described here). After the filling of the cylinder is completed, the moving mold 5 and the fixed mold 4 are attached and the mold is closed. Figure 7 As shown, high-pressure liquid (e.g., 63 MPa) is input through the high-pressure oil inlet 25 of the master cylinder, causing the piston 21 of the master cylinder to lock the middle plate 6, the moving mold 5 and the fixed mold 4, thus completing the static sealing mold locking.

[0028] Example 4 like Figure 8 and Figure 9 As shown, unlike the above embodiments, this embodiment consists of an opening and closing mold cylinder and two locking cylinders. The opening and closing mold cylinder comprises an opening and closing mold cylinder piston rod 33, an opening and closing mold cylinder piston 34, and an opening and closing mold cylinder body 36. The opening and closing mold cylinder body 36 has an opening and closing mold cylinder closing oil inlet 35 and an opening mold cylinder opening oil inlet 32. The locking cylinder comprises a passive locking cylinder body 28 and a passive locking cylinder piston 29. A passive locking cylinder piston sealing ring 27 is located between the passive locking cylinder body 28 and the passive locking cylinder piston 29. The passive locking cylinder body 28 has a passive locking cylinder high-pressure oil inlet 30 and a passive locking cylinder high-pressure oil inlet 31. The opening and closing mold cylinder body 36 and the two passive locking cylinder bodies 28 are respectively fixed to the tail plate 2, and the opening and closing mold cylinder piston rod 33 and the two passive locking cylinder pistons 29 are respectively fixed to the middle plate 6. Figure 8When the mold is in the open state, and the mold is to be closed, low-pressure liquid (e.g., 15 MPa) is input into the mold-closing cylinder inlet 35 to drive the mold-closing cylinder piston 34 and piston rod 33, pushing the middle plate 6 and moving mold 5 to move and make the moving mold 5 and fixed mold 4 close together to complete the mold closing. At the same time, the oil inlet and outlet pipes 22 of the two mother and daughter cylinders also passively follow the movement of the middle plate 6. The high-pressure oil inlet 31 of the passive mold-closing cylinder body 28 is connected to the filling valve and the liquid tank, so that the inside of the passive mold-closing cylinder body 28 is filled with liquid. After the mold is closed, the filling valve is closed. Figure 9 As shown, at this time, the passive mold-locking cylinder body 28 and the passive mold-locking cylinder piston 29 are relatively stationary. High-pressure liquid is input through the high-pressure oil inlet 30 of the passive mold-locking cylinder, causing the passive mold-locking cylinder piston 29 to transmit pressure to the middle plate 6, locking the moving mold 5 and the fixed mold 4, thus completing the static sealing mold-locking. Figure 8 and Figure 9 The hydraulic cylinder for opening and closing the mold of the drive plate 6 shown can be replaced by other transmission methods, such as screw and nut transmission, gear and rack transmission, and rope traction transmission, etc. In this embodiment, the passive mold locking cylinder body 28 can be connected to the plate 6, and the passive mold locking cylinder piston 29 can be connected to the tail plate 2 to achieve the same goal. The passive mold locking cylinder piston sealing ring 27 can be installed on the passive mold locking cylinder body 28 or on the passive mold locking cylinder piston 29.

[0029] Example 5 like Figure 10 and Figure 11 As shown, this illustrates the mold-locking principle of a two-platen machine. Figure 10 As shown, there is a two-platen machine with a fixed template 37 and a moving template 38. The fixed mold 4 and the moving mold 5 are respectively mounted on the fixed template 37 and the moving template 38. There are two-platen machine locking cylinders 39 distributed at the four corners of the fixed template 37 (only one is shown in the figure). Inside the locking cylinder 39, there is a piston 42 connected to the piston rod 44. The piston sealing ring 43 is located between the piston 42 and the locking cylinder 39. There is a piston rod sealing ring 46 on the piston rod. Between rod 44 and the two-platen machine locking cylinder 39, near the two-platen moving template 38, there is a two-platen machine brake device 47. The figure shows the two-platen machine brake device 47 in the braked state. The two-platen machine locking cylinder 39 has a two-platen machine locking cylinder 40 and a high-pressure oil inlet 45. Low-pressure liquid (e.g., 15 MPa) is input through the two-platen machine locking cylinder 40, causing the two-platen machine piston to pull the two-platen moving template 38 and the moving mold 5 through the two-platen machine piston rod 44 and the two-platen machine brake device 47, so that the moving mold 5 and the fixed mold 4 are in contact. After completion, as shown in the figure... Figure 11 As shown, high-pressure liquid (63 MPa) is then introduced through high-pressure oil inlet 45, causing the two-platen machine piston 42, the two-platen machine piston rod 44, and the two-platen machine brake device 47 to pull the two-platen moving template 38, thereby locking the moving mold 5 and the fixed mold 4, completing the static sealing mold locking. Figure 20The piston 42 and piston rod 44 of the second-platen machine are respectively connected to the locking cylinder 39 of the second-platen machine with O-rings 50 and retaining rings 51, which respectively withstand the liquid pressure in the direction of the arrow in the figure. Figure 20 For the specific assembly structure of the piston 42, O-ring 50, and retaining ring 51 of the second-stage machine, please refer to [reference needed]. Figure 13 structure, Figure 20 For the specific assembly mechanism of the piston rod 44, O-ring 50, and retaining ring 51 of the two-platen machine, please refer to [reference needed]. Figure 17 structure.

[0030] Example 6 Unlike the above embodiments, when a dynamic seal is used between the cylinder and the piston, a high-pressure resistant combination seal can be used, such as a V-shaped combination seal consisting of a pressure ring, a V-shaped ring, and a support ring, or a U-shaped seal consisting of a seal and a spring, or a drum-shaped combination seal, etc. In various embodiments of the present invention, since the pressure inside the cylinder is low when the cylinder and the piston move relative to each other, the pressure on the seal is small, and the frictional resistance between the seal and the cylinder or piston is relatively small, resulting in a much longer service life, thereby greatly improving the pressure of the hydraulic system.

[0031] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived without inventive effort should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A static sealing clamping hydraulic cylinder for injection molding and die casting machines, comprising a load-bearing frame composed of head and tail plates and tie rods, the load-bearing frame being mounted on a machine frame or the head and tail plates being directly mounted on the machine frame, the machine frame or tie rods having guide rails and head and tail plates, and a middle plate in the middle, the middle plate being mounted on the guide rails, characterized in that: The hydraulic cylinder body and piston are connected to the tail plate and the middle plate respectively or installed in reverse. There is a high-pressure resistant sealing ring, extrusion type or lip type sealing ring between the cylinder body and the piston. There are low-pressure and high-pressure liquid inlets. When the mold is opened and closed, it is driven by low-pressure liquid. After the mold is closed, when the cylinder body and piston are in a relatively static state, high-pressure or ultra-high-pressure liquid is input to complete the static sealing mold locking.

2. The static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines according to claim 1, characterized in that: Extrusion-type seals with retaining rings or slip rings.

3. The static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines according to claim 1, characterized in that: The high-pressure resistant sealing ring is either a plug-sealed V-shaped combination sealing ring or a drum-shaped combination sealing ring.

4. A static sealing clamping hydraulic cylinder for injection molding and die casting machines, comprising a load-bearing frame composed of head and tail plates and tie rods, wherein the load-bearing frame is mounted on the machine frame or the head and tail plates are directly mounted on the machine frame, and the machine frame or tie rods have guide rails and head and tail plates, with a middle plate mounted on the guide rails, characterized in that: The cylinder body and the piston of the mother cylinder are respectively mounted on the tail plate and the middle plate. There is a high-pressure resistant sealing ring, or a compression type or lip type sealing ring between the cylinder body and the piston of the mother cylinder. The opening and closing of the mold is completed by the piston driven by the liquid supply of the daughter cylinder. There is a liquid tank connected to the cylinder body or the piston of the mother cylinder through the liquid filling valve, so that the cylinder body is filled with liquid. After the mold is closed, the liquid filling valve is closed, and the cylinder body and the piston of the mother cylinder are in a relatively static state. High pressure or ultra-high pressure liquid is injected into the mother cylinder to complete the static sealing and mold locking.

5. The static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines according to claim 4, characterized in that: Extrusion-type seals with retaining rings or slip rings.

6. The static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines according to claim 4, characterized in that: The high-pressure resistant sealing ring is either a plug-sealed V-shaped combination sealing ring or a drum-shaped combination sealing ring.

7. A static sealing mold-locking hydraulic cylinder for injection molding and die casting machines, comprising a load-bearing frame consisting of head and tail plates and tie rods, the load-bearing frame being mounted on a machine frame or the head and tail plates being directly mounted on the machine frame, guide rails and head and tail plates on the machine frame or tie rods, and a middle plate mounted on a movable guide rail and driven by a middle plate drive device to move the middle plate to open and close the mold, characterized in that: A single-acting hydraulic cylinder is located between the tail plate and the middle plate. After mold closing, there is a gap between the piston and the middle plate, which is filled by the mold-directing moving block. The mold-directing moving block has a driving device that can push the mold-directing moving block into or out of the machine after mold closing to open the mold. The driving direction is perpendicular to the mold closing direction. The mold-directing moving block has an inclined surface. There is a high-pressure resistant sealing ring, extrusion type, or lip type sealing ring between the cylinder body and the piston of the mother cylinder. Corresponding inclined surfaces can be set on the middle plate or the piston. When the piston end and the tail plate are opposite, a corresponding inclined surface is set at the bottom of the cylinder body. After the middle plate driving device drives the middle plate to close the mold, the mold-directing moving block is driven by the driving device to fill the space between the single-acting hydraulic cylinder and the middle plate. Due to the effect of the inclined surface, the cylinder body, piston, middle plate, and fixed and moving mold are pressed between the head and tail plates. The cylinder body and piston are relatively stationary. High-pressure or ultra-high-pressure liquid is injected into the inlet to complete the static sealing and mold locking.

8. The static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines according to claim 7, characterized in that: Extrusion-type seals with retaining rings or slip rings.

9. The static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines according to claim 7, characterized in that: The high-pressure resistant sealing ring is either a plug-sealed V-shaped combination sealing ring or a drum-shaped combination sealing ring.

10. A static sealing mold-locking hydraulic cylinder for injection molding and die casting machines, comprising a load-bearing frame consisting of head and tail plates and tie rods, the load-bearing frame being mounted on a machine frame or the head and tail plates being directly mounted on the machine frame, guide rails and head and tail plates on the machine frame or tie rods, and a middle plate mounted on a movable guide rail and driven by a middle plate drive device to open and close the mold, characterized in that: The cylinder and piston are connected to the tail plate and the middle plate respectively or installed in reverse. There is a high-pressure resistant sealing ring, or a compression type or lip type sealing ring between the cylinder and the piston. When the middle plate drive device drives the middle plate to move, a liquid tank is connected to the cylinder or piston through the filling valve to fill the cylinder with liquid. After the mold is closed, the filling valve is closed. At this time, the cylinder and piston are relatively stationary. High-pressure or ultra-high-pressure liquid is injected into the cylinder through the cylinder or piston to complete the static sealing and mold locking.

11. The static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines according to claim 10, characterized in that: Extrusion-type seals with retaining rings or slip rings.

12. The static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines according to claim 10, characterized in that: The high-pressure resistant sealing ring is either a plug-sealed V-shaped combination sealing ring or a drum-shaped combination sealing ring.

13. A static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines, comprising a two-platen mechanism, a positioning plate, and a moving plate, the moving plate being mounted on a guide rail, a drive mechanism driving the moving plate to move, and a brake device engaging after mold closing, characterized in that: The hydraulic cylinder for locking the mold has a high-pressure resistant sealing ring, or a compression type or lip type sealing ring between the cylinder body and the piston. After the brake is applied, low-pressure liquid is injected to make the stationary and moving molds stick together. At the same time, the brake mechanism and the end face of the moving mold are pressed together. Then, high-pressure or ultra-high-pressure liquid is injected to complete the static sealing and locking of the mold.

14. The static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines according to claim 13, characterized in that: Extrusion-type seals with retaining rings or slip rings.

15. The static sealing mold-locking hydraulic cylinder for injection molding and die-casting machines according to claim 13, characterized in that: The high-pressure resistant sealing ring is either a plug-sealed V-shaped combination sealing ring or a drum-shaped combination sealing ring.

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