Cylinder sealing structure, hot runner cylinder and needle valve hot runner system

Abstract

The utility model discloses a cylinder sealing structure, a hot runner cylinder and a needle valve hot runner system. The air cylinder sealing structure comprises movable sealing rings, and the movable sealing rings are arranged between the top of a piston and a cylinder body and between the bottom of the piston and a runner guide sleeve respectively. The movable sealing ring is composed of two arc-shaped sealing strips of the same structure, the inner wall of one end of each sealing strip extends out of a connecting part, the outer wall of the other end of each sealing strip extends out of a splicing part, the connecting parts of the two sealing strips are connected with the splicing parts, and the movable sealing ring is made of beryllium copper. Due to the fact that the movable sealing ring is formed by splicing the two sealing strips, the movable sealing ring is not prone to displacement when the piston moves. And the movable sealing ring made of beryllium copper has higher hardness and wear resistance, so that the movable sealing ring can still keep the original shape in a high-temperature working environment. The problem that an existing hot runner air cylinder sealing ring is prone to damage is solved.

Description

Technical Field

[0001] The utility model relates to the field of needle valve hot runner systems, in particular to a cylinder sealing structure, a hot runner cylinder and a needle valve hot runner system. Background Art

[0002] PFV (Chinese name: soluble polytetrafluoroethylene) material is widely used in new energy batteries due to its excellent self-extinguishing properties and incombustibility. However, its injection molding process requires a very high melting temperature. For example, the PFA material with the US DuPont brand of 440HP requires a melt temperature of 390°C. At such a high temperature, it is difficult for ordinary needle valve hot runner cylinder systems to maintain stable production. The needle valve hot runner system includes three major systems: cylinder system, manifold system, and hot nozzle system. The melt temperature required by PFA material is 390°C, which means that when the hot nozzle system and manifold system are working, they will also be heated to 390°C. The cylinder system is in contact with the manifold, and through heat transfer, the temperature of the cylinder system will also be transferred to about 390°C; in addition, the piston reciprocates at high speed in the cylinder body, and a large amount of heat will be generated due to friction. The sealing ring in the existing cylinder system is an annular rubber ring, which is difficult to maintain long-term operation in such a high-temperature environment. In such a high-temperature environment, the sealing ring will often be damaged to varying degrees in a short period of time, thereby affecting the normal operation of the cylinder system, further causing a great impact on production. Utility Model Content

[0003] In order to solve the technical problem that the annular sealing ring of the hot runner cylinder in the prior art is easily damaged, the utility model provides a cylinder sealing structure, a hot runner cylinder and a needle valve hot runner system.

[0004] The technical solution adopted by the utility model is:

[0005] The utility model proposes a cylinder sealing structure, a hot runner cylinder and a needle valve hot runner system. The cylinder sealing structure comprises a dynamic sealing ring, which is respectively arranged between the piston top and the cylinder body of the cylinder and between the piston bottom and the runner guide sleeve;

[0006] The dynamic sealing ring includes a plurality of arc-shaped sealing strips that can be spliced. A connecting portion extends from one end of the sealing strip and a splicing portion extends from the other end. The connecting portion of the sealing strip can be connected to the splicing portion of another adjacent sealing strip. The dynamic sealing ring is made of beryllium copper.

[0007] Furthermore, the top side wall of the piston is provided with a first annular groove for mounting the dynamic sealing ring, and the bottom side wall of the piston is provided with a second annular groove for mounting the dynamic sealing ring.

[0008] Furthermore, it is characterized in that the sealing surface of the dynamic sealing ring is flush with the surface of the first annular groove or the second annular groove in which the dynamic sealing ring is provided.

[0009] The utility model also provides a hot runner cylinder, comprising any one of the cylinder sealing structures.

[0010] Furthermore, the hot runner cylinder comprises:

[0011] A cylinder body, wherein a cover plate is provided on the top of the cylinder body, a gap is left between the cover plate and the cylinder body as a first air passage, and at least one air hole is provided at the bottom of the cylinder body as a second air passage;

[0012] A flow channel guide sleeve, the flow channel guide sleeve is connected to the bottom of the cylinder body;

[0013] A piston, wherein the top of the piston is arranged in the cylinder body, and the bottom of the piston extends into the flow channel guide sleeve. The bottom of the cylinder body restricts the top of the piston to move only in the cylinder. When air enters the cylinder body from the first air channel, the piston moves downward. When air enters the cylinder body from the second air channel, the piston moves upward.

[0014] The dynamic sealing rings are respectively arranged on the top of the piston and the bottom of the piston.

[0015] Furthermore, the bottom of the piston is connected to a needle valve extending out of the flow channel guide sleeve.

[0016] The utility model also proposes a needle valve hot runner system, including a fixed mold fixing plate, a diverter plate and a hot nozzle system, and also includes the hot runner cylinder. The fixed mold fixing plate is provided with a mounting position for mounting the hot runner cylinder.

[0017] Furthermore, static sealing rings are respectively provided on the bottom surface of the cover plate in contact with the fixed mold fixing plate, and on the bottom of the cylinder body and located outside the second air passage at a location in contact with the fixed mold fixing plate, and the static sealing rings are made of beryllium copper.

[0018] Furthermore, a first gap communicating with the first air channel is left between the fixed mold fixing plate and the cylinder body, a second gap communicating with the second air channel is left between the fixed mold fixing plate and the flow channel guide sleeve, and a first air pipe communicating with the first gap and a second air pipe communicating with the second gap are provided in the fixed mold fixing plate.

[0019] Furthermore, after the static sealing ring is installed, the sealing surface of the static sealing ring protrudes from the cover plate or the bottom of the cylinder body by 0.1 to 0.5 mm.

[0020] Compared with the prior art, the utility model discloses a cylinder sealing structure, a hot runner cylinder and a needle valve hot runner system. The cylinder sealing structure proposed in the utility model includes a dynamic sealing ring, which is respectively arranged between the top of the piston and the cylinder body, and between the bottom of the piston and the runner guide sleeve; the dynamic sealing ring is composed of two arc-shaped sealing strips with the same structure, a connecting portion extends from the inner wall of one end of the sealing strip, and a splicing portion extends from the outer wall of the other end, the connecting portion of the two sealing strips is connected to the splicing portion, and the dynamic sealing ring is made of beryllium copper. Since the dynamic sealing ring is composed of two sealing strips spliced ​​together, the dynamic sealing ring is not easy to shift when the piston moves. And the dynamic sealing ring made of beryllium copper has high hardness and wear resistance, which can ensure that the dynamic sealing ring can still maintain its original shape under high temperature working environment. The problem that the existing hot runner cylinder sealing ring is easily damaged is solved. In addition, the needle valve hot runner system proposed in the present application is also provided with a static sealing ring on the cover plate and the bottom of the cylinder body to prevent the cylinder body and the upper cover plate from colliding with the fixed mold fixing plate and making noise when the hot runner cylinder is running. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0022] Figure 1 This is a schematic diagram of the internal structure of an embodiment of the utility model;

[0023] Figure 2 for Figure 1 A magnified image of point A;

[0024] Figure 3 This is a schematic diagram of a dynamic seal ring according to an embodiment of the utility model;

[0025] Figure 4 This is a schematic diagram of the splicing of the sealing strips of the embodiment of the utility model;

[0026] Figure 5 This is a schematic diagram of installing a dynamic sealing ring on a piston according to an embodiment of the utility model;

[0027] Figure 6 This is a schematic diagram of a needle valve hot runner system according to an embodiment of the utility model;

[0028] Figure 7 It is a top view of a schematic diagram of a needle valve hot runner system according to an embodiment of the utility model;

[0029] Figure 8 This is a schematic diagram of the installation of the cover plate and the fixed mold fixing plate of the embodiment of the utility model;

[0030] 1. Hot runner cylinder; 2. Fixed mold fixing plate; 21. Divider plate; 3. Hot nozzle system;

[0031] 4. Dynamic sealing ring; 41. Sealing strip; 42. Splicing part; 43. Connecting part;

[0032] 5. Static sealing ring;

[0033] 61. Cylinder body; 62. Piston; 63. Cover plate; 64. Runner guide sleeve. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] The principle and structure of the present utility model are described in detail below with reference to the accompanying drawings and embodiments.

[0036] PFV (Chinese name: soluble polytetrafluoroethylene) material is widely used in new energy batteries due to its excellent self-extinguishing properties and incombustibility. However, its injection molding process requires a very high melting temperature. For example, the PFA material with the US DuPont brand of 440HP requires a melt temperature of 390°C. At such a high temperature, it is difficult for ordinary needle valve hot runner cylinder 1 systems to maintain stable production. The needle valve hot runner system includes three major systems: cylinder system, manifold system, and hot nozzle system. The melt temperature required by PFA material is 390°C, which means that when the hot nozzle system and manifold system are working, they will also be heated to 390°C. The cylinder system is in contact with the manifold, and the temperature of the cylinder system will be transferred to about 390°C through heat transfer. In addition, the piston reciprocates at high speed in the cylinder body, and a large amount of heat will be generated due to friction. The sealing ring in the existing cylinder system is a rubber ring, which is difficult to maintain long-term operation in such a high-temperature environment. In such a high-temperature environment, the sealing ring will often be damaged to varying degrees in a short period of time, thereby affecting the normal operation of the cylinder system and further causing a great impact on production.

[0037] like Figure 1-4 As shown, the utility model proposes a cylinder sealing structure, including a dynamic sealing ring 4. The dynamic sealing ring 4 is arranged between the top of the piston 62 of the cylinder and the cylinder body 61 and between the bottom of the piston 62 and the flow channel guide sleeve 64. The interior of the cylinder is divided into two relatively sealed air chambers by the dynamic sealing ring 4, and the two air chambers change with the movement size of the piston 62.

[0038] like Figure 5As shown, the top and bottom of the piston 62 are cylindrical, the diameter of the top cylinder is larger than the diameter of the bottom cylinder, a first step is formed between the top and the bottom, the top of the piston 62 is arranged in the cylinder body 61 of the hot runner cylinder 1, the bottom extends into the runner guide sleeve 64 of the hot runner cylinder 1, and the piston 62 can move up and down along the cylinder body 61. A first annular groove is provided on the outer side wall of the top of the piston 62 for mounting the dynamic seal ring 4, and a second annular groove is also provided on the outer side wall of the bottom of the piston 62 for mounting the dynamic seal ring 4.

[0039] like Figure 3-5 As shown, the dynamic seal ring 4 includes a plurality of arc-shaped sealing strips that can be spliced. In this embodiment, two sealing strips are provided. The shape of the sealing strip 41 is arc-shaped, and the structures of the two sealing strips 41 are the same. A connecting portion 43 extends from the inner wall of one end of the sealing strip 41. A splicing portion 42 extends from the outer wall of the other end of the sealing strip 41. The splicing portion 42 corresponds to the connecting portion 43 and is used to splice with the connecting portion 43 of another sealing strip 41. After splicing, the splicing portion 42 presses the connecting portion 43 on the outside of the connecting portion 43. The shape of the splicing portion 42 matches the connecting portion 43, ensuring that the two sealing strips 41 can be precisely spliced ​​together to form a dynamic seal ring 4. The two sealing strips 41 can be spliced ​​into a complete circle and stuck in the first annular groove at the top of the piston 62 or the second annular groove at the bottom of the piston 62, and the sealing surface of the dynamic seal ring 4 is flush with the surface of the first annular groove and the second annular groove, which plays a sealing role with the cylinder body 61 of the hot runner cylinder 1 or the hot runner guide sleeve 64 of the hot runner cylinder 1. The dynamic seal ring 4 is made of beryllium copper, which has high hardness and wear resistance, and can ensure that the dynamic seal ring 4 can still maintain its original shape in a high-temperature working environment. At the same time, the dynamic seal ring is formed by splicing two sealing strips, which is easy to install, and the seal ring is not easy to be misaligned when the piston moves.

[0040] The sealing ring we currently use is made of high-temperature resistant rubber material, and its softening temperature is 360°C, while the softening temperature of beryllium copper reaches 930°C, which is far higher than the softening temperature of traditional high-temperature resistant rubber sealing rings, solving the problem that the existing hot runner cylinder 1 is easily damaged at excessively high temperatures.

[0041] The dimensions of the groove and the dynamic seal ring 4 are as follows: depth H, outer diameter φD, inner diameter φd.

[0042] H dynamic sealing ring = H groove, φD dynamic sealing ring = φD groove + (0.1~0.2mm), φd dynamic sealing ring = φd groove.

[0043] The dynamic seal ring is composed of two sealing strips 41, and W represents the thickness.

[0044] The maximum thickness of the extension part and the connection part W = (φD dynamic seal ring - φd dynamic seal ring) / 2;

[0045] W = W extension + W connection;

[0046] To ensure interlocking stability, W joint = (0.5-0.67)W.

[0047] The present application also proposes a hot runner cylinder 1 using the cylinder sealing structure of the present application.

[0048] like Figure 1-2 As shown, the hot runner cylinder 1 includes: a cylinder body 61 , a cover plate 63 , a runner guide sleeve 64 and a piston 62 .

[0049] The cylinder body 61 is in the shape of a cylindrical barrel, with both ends not closed, and a circular cover plate 63 covering the upper opening is provided at the top thereof, and a gap is left between the cover plate 63 and the cylinder body 61 as a first air passage, and the cover plate 63 can move within a small range due to the movement of the piston 62. The bottom end of the cylinder body 61 is bent inward, and at least one air hole is provided at the bend as a second air passage.

[0050] The hot runner guide sleeve 64 is cylindrical barrel-shaped, with both ends not closed and a diameter smaller than the diameter of the cover plate 63 . The top is connected to the inward bend of the bottom of the cylinder body 61 by threads or clamping, forming a first step between the hot runner guide sleeve 64 and the cylinder body 61 .

[0051] The top and bottom of the piston 62 are cylindrical, the diameter of the top cylinder is larger than the diameter of the bottom cylinder, and a second step is formed between the top and the bottom. The outer wall of the top of the piston 62 is provided with a first annular groove for mounting the dynamic seal ring 4, and the outer wall of the bottom of the piston 62 is provided with a second annular groove for mounting the dynamic seal ring 4. The top of the piston 62 is arranged in the cylinder body 61 of the hot runner cylinder 1, and has an interference fit with the inside of the cylinder, and the bottom extends into the runner guide sleeve 64 of the hot runner cylinder 1. The piston 62 is restricted by the second step and the first step, so that the top of the piston 62 can only move in the cylinder body 61, that is, between the first step and the cover plate 63. The bottom of the piston 62 is also provided with a needle valve, and the needle valve extends out of the bottom of the guide sleeve.

[0052] Compressed air enters the cylinder 61 from the first air passage, acts on the top surface of the piston 62, and moves the piston 62 downward. At the same time, the gas between the top of the piston 62 and the bottom of the cylinder 61 flows out from the second air passage. Compressed air enters the cylinder 61 from the second air passage, acts on the bottom surface of the top of the piston 62, and moves the piston 62 upward. The gas between the piston 62 and the cover plate 63 is discharged from the first air passage. When the hot runner cylinder 1 is working, the piston 62 reciprocates at high speed in the cylinder 61. During this period, due to friction, a large amount of heat is easily generated. The dynamic seal 4 is made of beryllium copper material to withstand higher temperatures.

[0053] like Figure 7-8As shown, the present application also proposes a needle valve hot runner system, which uses the hot runner cylinder of the present application. The needle valve hot runner system includes a fixed mold plate 2, a diverter plate 21 and a hot nozzle system 3. The fixed mold plate is provided with a mounting position for mounting the hot runner cylinder, the diverter plate is connected to the bottom surface of the fixed mold plate 2, the hot nozzle system is arranged on the bottom surface of the diverter plate, the valve needle penetrates from the hot runner cylinder into the nozzle of the hot nozzle system, and the hot nozzle of the hot nozzle system 3 and the diverter plate 21 are installed on the injection mold. By utilizing the principle of heating, the required material is always kept in a molten state after coming out of the barrel of the injection molding machine, ensuring the water level of the product, so that when the finished product is demolded, the nozzle mouth is closed due to the action of the piston driving the needle valve, avoiding the appearance of one or several water outlets, thereby no waste is generated. The structure of the needle valve hot runner system is relatively common and will not be described in detail in the present application.

[0054] The fixed mold fixing plate 2 is provided with a mounting position for mounting the hot runner cylinder 1 , and a gap is left between the hot runner cylinder 1 and the fixed mold fixing plate 2 as an air channel.

[0055] The diameter of the cover plate 63 is larger than the upper end diameter of the cylinder body 61, so the edge of the cover plate 63 exceeds the edge of the cylinder body 61, and the bottom edge of the cover plate 63 contacts the fixed mold fixing plate 2. The bottom surface of the cover plate 63 in contact with the fixed mold fixing plate 2 is provided with a third annular groove, and a static sealing ring 5 is provided in the third annular groove to prevent the cover plate 63 from moving and generating noise. The bottom of the cylinder body 61 contacts the fixed mold fixing plate 2, and a fourth annular groove is provided on the bottom surface of the cylinder body 61 in contact with the fixed mold fixing plate 2. A static sealing ring 5 is provided in the fourth annular groove to prevent the hot runner cylinder 1 and the fixed mold fixing plate 2 from moving and generating noise. A static sealing ring 5 can also be provided at the bottom surface of the cover plate 63 corresponding to the piston 62, and a fifth annular groove is provided at the bottom surface of the cover plate 63 corresponding to the piston 62. A static sealing ring 5 is provided in the fifth annular groove to prevent the piston 62 from moving up and down and hitting the cover plate 63 and generating noise when working. The static seal ring 5 is annular and made of beryllium copper. After installation, the static seal ring 5 protrudes from the cover plate 63 or the bottom of the cylinder body 61 by 0.1 to 0.5 mm. A first gap is left between the side wall of the cylinder body 61 and the fixed mold fixing plate 2, and the first gap is connected to the first air channel; a second gap is left between the flow channel guide sleeve 64 and the fixed mold fixing plate 2, and the second gap is connected to the second air channel; the fixed mold fixing plate 2 is provided with a first air pipe connected to the first gap and a second air pipe connected to the second gap. When compressed gas is introduced into the first gap through the first air pipe, the compressed gas enters the cylinder body 61 through the first air channel after passing through the first gap from the first air pipe, and the piston 62 moves downward. The gas between the piston 62 and the connection between the cylinder body 61 and the flow channel guide sleeve 64 flows out from the second air channel to the second gap and then flows out from the second air pipe. When compressed gas is introduced into the first gap through the second air pipe, the compressed gas passes through the second gap from the second air pipe and then enters the cylinder body 61 through the second air channel, the piston 62 moves upward, and the gas between the piston 62 and the cover plate 63 flows out from the first air channel to the first gap and then flows out from the first air pipe.

[0056] The dimensions of the groove and the static seal ring 5 are as follows:

[0057] Depth h, outer diameter φD, inner diameter φd.

[0058] h static sealing ring = h groove + (0.1~0.5mm), φD static sealing ring = φD groove, φd static sealing ring 5 = φd groove.

[0059] The height of the static seal ring 5 is 0.1-0.5mm greater than the groove height. Since beryllium copper is soft, when the static seal ring 5 is installed, under the action of the cover plate 63 and the fixed mold fixing plate 2, the beryllium copper seal ring (beryllium copper has good anti-friction and self-lubricating properties) expands, which can ensure a good sealing effect of the static seal ring 5. If it is less than 0.1mm, the seal between the cover plate 63 and the fixed mold fixing plate 2 will be affected due to insufficient expansion; if it is higher than 0.5mm, there will be too much excess, and the transfer will not be in place, affecting the sealing.

[0060] Compared with the prior art, the cylinder sealing structure proposed in the utility model includes a dynamic sealing ring 4, which is respectively arranged between the top of the piston 62 and the cylinder body 61, and between the bottom of the piston 62 and the runner guide sleeve 64; the dynamic sealing ring 4 is composed of two arc-shaped sealing strips 41 with the same structure, a connecting portion 43 extends from the inner wall of one end of the sealing strip 41, and a splicing portion 42 extends from the outer wall of the other end, the connecting portion 43 of the two sealing strips 41 is connected to the splicing portion 42, and the dynamic sealing ring 4 is made of beryllium copper. Since the dynamic sealing ring 4 is composed of two sealing strips 41 spliced ​​together, the dynamic sealing ring 4 is not easy to shift when the piston 62 moves. And the dynamic sealing ring 4 made of beryllium copper has high hardness and wear resistance, which can ensure that the dynamic sealing ring 4 can still maintain its original shape under high temperature working environment. The problem that the existing hot runner cylinder 1 sealing ring is easily damaged is solved. The needle valve hot runner system proposed in the present application is also provided with a static sealing ring 5 at the cover plate 63 and the bottom of the cylinder body 61 to prevent the cylinder body 61 and the upper cover plate 63 from colliding with the fixed mold fixing plate 2 and making noise when the hot runner cylinder 1 is running.

[0061] It should be noted that the terms used above are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0062] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps described in these embodiments do not limit the scope of the utility model. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0063] In the description of the present utility model, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present utility model; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0064] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0065] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the utility model.

[0066] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A cylinder sealing structure, characterized in that: It includes a dynamic sealing ring, which is respectively arranged between the piston top and the cylinder body of the cylinder, and between the piston bottom and the flow channel guide sleeve; The dynamic sealing ring includes a plurality of arc-shaped sealing strips that can be spliced ​​together. A connecting portion extends from one end of the sealing strip and a splicing portion extends from the other end. The connecting portion of the sealing strip can be connected to the splicing portion of an adjacent sealing strip. The dynamic sealing ring is made of beryllium copper.

2. The cylinder sealing structure according to claim 1, characterized in that: The top side wall of the piston is provided with a first annular groove for mounting the dynamic sealing ring, and the bottom side wall of the piston is provided with a second annular groove for mounting the dynamic sealing ring.

3. The cylinder sealing structure according to claim 2, characterized in that: The sealing surface of the dynamic sealing ring is flush with the surface of the first annular groove or the second annular groove where the dynamic sealing ring is provided.

4. A hot runner cylinder, characterized in that: It comprises the cylinder sealing structure as described in any one of claims 1 to 3.

5. The hot runner cylinder according to claim 4, characterized in that: The hot runner cylinder comprises: A cylinder body, wherein a cover plate is provided on the top of the cylinder body, a gap is left between the cover plate and the cylinder body as a first air passage, and at least one air hole is provided at the bottom of the cylinder body as a second air passage; A flow channel guide sleeve, the flow channel guide sleeve is connected to the bottom of the cylinder body; A piston, wherein the top of the piston is arranged in the cylinder body, and the bottom of the piston extends into the flow channel guide sleeve. The bottom of the cylinder body restricts the top of the piston to move only in the cylinder. When air enters the cylinder body from the first air channel, the piston moves downward. When air enters the cylinder body from the second air channel, the piston moves upward. The dynamic sealing rings are respectively arranged on the top of the piston and the bottom of the piston.

6. The hot runner cylinder according to claim 5, characterized in that: The bottom of the piston is connected with a needle valve extending out of the flow channel guide sleeve.

7. A needle valve hot runner system, comprising a fixed mold plate, a diverter plate and a hot nozzle system, characterized in that: It comprises the hot runner cylinder according to any one of claims 5 to 6, wherein the fixed mold fixing plate is provided with a mounting position for mounting the hot runner cylinder.

8. The needle valve hot runner system according to claim 7, characterized in that: Static sealing rings are respectively provided at the bottom surface of the cover plate in contact with the fixed mold fixing plate, and at the contact point between the bottom of the cylinder body and the fixed mold fixing plate. The material of the static sealing rings is beryllium copper.

9. The needle valve hot runner system according to claim 8, characterized in that: A first gap communicating with the first air channel is left between the fixed mold fixing plate and the cylinder body, a second gap communicating with the second air channel is left between the fixed mold fixing plate and the flow channel guide sleeve, and a first air pipe communicating with the first gap and a second air pipe communicating with the second gap are provided in the fixed mold fixing plate.

10. The needle valve hot runner system according to claim 9, characterized in that: After the static sealing ring is installed, the sealing surface of the static sealing ring protrudes from the cover plate or the bottom of the cylinder body by 0.1-0.5 mm.

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