A high-temperature dynamic sealing structure and assembly method for a fire-operated actuator

Abstract

This invention discloses a high-temperature dynamic sealing structure and assembly method for a flammable actuation device, relating to the field of high-temperature sealing technology for flammable actuation mechanisms. The invention is used for a cylindrical piston head, including a first mounting groove coaxially disposed at the head end of the piston head and a second mounting groove coaxially disposed and spaced apart. One end of the first mounting groove extends through the head end of the piston head. The piston head has an external thread section and a sleeve section on the outer wall of the first mounting groove. A graphite ring is sleeved inside the sleeve section, and a compression nut is threaded onto the external thread section. A rubber ring is sleeved inside the second mounting groove. The piston head is slidably assembled within a housing, and the outer walls of the graphite ring and the rubber ring slidably abut against the inner cavity of the housing. The compression nut is used to maintain the graphite ring in an expanded state. This achieves the purpose of adapting to a flammable actuation device for high-temperature dynamic sealing and can replace existing room-temperature dynamic seals in situ.

Description

Technical Field

[0001] This invention relates to the field of high-temperature sealing technology for flammable working mechanisms, specifically, to a high-temperature dynamic sealing structure and assembly method for a flammable working device. Background Art

[0002] Reliable dynamic seals are crucial for the safe and stable operation of actuators. Conventional pyrotechnic actuators typically use rubber O-rings as dynamic seals. However, pyrotechnic actuators used in hypersonic weapons often need to withstand high ambient temperatures, and the temperature resistance of rubber O-rings cannot meet these requirements.

[0003] Current research on high-temperature dynamic sealing technology mainly focuses on ceramic sheet seals and braided fiber rope structure seals. However, their operating environments differ significantly from those of pyrotechnic actuation devices, making them unsuitable for the dynamic sealing requirements of these devices. Besides the aforementioned novel high-temperature seals, flexible graphite has gained widespread application in high-temperature sealing due to its advantages such as self-lubrication, high thermal conductivity, and chemical stability. However, graphite itself is brittle, prone to delamination during installation, and susceptible to oxidation and moisture absorption during long-term storage. Furthermore, existing dynamic seals for pyrotechnic actuation devices are not temperature-resistant, and temperature-resistant seals differ significantly from existing sealing structures, requiring entirely new designs and verifications, which are no longer adequate for the development needs of next-generation hypersonic weapons.

[0004] Therefore, it is necessary to design a high-temperature dynamic sealing structure for fire-operated devices that can replace the existing sealing structure in situ and withstand temperatures above 600℃. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature dynamic sealing structure for a fire-operated device, so as to adapt to the fire-operated device for high-temperature dynamic sealing and to replace the existing normal-temperature dynamic seal in situ.

[0006] To achieve the above objectives, the present invention employs the following technical means:

[0007] A high-temperature dynamic sealing structure for a fire-working device is used for a cylindrical piston head, including a first mounting groove coaxially disposed at the head end of the piston head and a second mounting groove coaxially disposed and spaced apart, wherein one end of the first mounting groove extends through the head end of the piston head.

[0008] The piston head is located on the outer wall of the first mounting groove and has an external thread section and a sleeve section. A graphite ring is sleeved inside the sleeve section, and a crimp nut is threadedly installed on the external thread section. A rubber ring is sleeved inside the second mounting groove.

[0009] The piston head is slidably assembled inside the housing, and the outer walls of the graphite ring and the rubber ring slide against the inner cavity of the housing.

[0010] The crimp nut is used to maintain the graphite ring in an expanded state.

[0011] Preferably, the main body of the crimp nut has a pin block on one end face facing the inner cavity of the housing, the inner cavity end face of the housing has a positioning groove that matches the pin block, and the outer wall of the tail end of the piston head has a hexagonal snap-fit ​​mechanism around its axis.

[0012] Furthermore, the pin block is arranged with equal circumferential angles around the axis of the crimp nut, and the number and position of the positioning grooves correspond to and match the pin block.

[0013] Furthermore, the outer diameter of the threaded end of the external thread section is the same as the outer diameter of the sleeve section, and the axial length of the graphite ring is greater than the axial length of the sleeve section.

[0014] Furthermore, the axial distance between the graphite ring and the sleeve segment differs by 0.1~0.2mm.

[0015] Furthermore, the contact surfaces of the piston head and the crimp nut with the inner cavity of the housing are coated with a molybdenum disulfide coating.

[0016] The high-temperature dynamic sealing structure of the flammable working device disclosed in this invention has the following beneficial effects for sealing operations of the flammable working device in high-temperature environments above 600°C:

[0017] In this design, the piston head is positioned so that its tip faces the direction of the high-temperature / high-pressure gas input, meaning the rubber ring is closer to the air side than the graphite ring. This allows the positioning of the graphite and rubber rings to combine the high-temperature sealing performance of the graphite ring with the room-temperature sealing protection of the rubber ring. In the room-temperature, non-operating state, the rubber ring's seal prevents external air and moisture from entering, preventing oxidation and moisture absorption failure of the internal graphite ring and special coating during storage. During high-temperature operation, the rubber ring fails due to the heat, and the graphite ring provides a dynamic seal. Furthermore, the compression nut allows the graphite ring to expand outwards, improving its sealing performance and ensuring reliable sealing of the actuator in high-temperature environments without altering the traditional piston shape. This prevents delamination failure of the graphite ring during room-temperature storage, installation, and high-temperature use, thus solving the problem of actuator sealing failure in high-temperature environments.

[0018] Furthermore, the present invention also provides an assembly method for the aforementioned high-temperature dynamic sealing structure of the fire-operated device. Its purpose is to prevent delamination of the graphite ring during installation, while ensuring that the graphite ring remains in a uniformly expanding state.

[0019] To achieve the above objectives, the assembly method involved in this invention is specifically as follows:

[0020] First, install the rubber ring and graphite ring into the second mounting groove and the first mounting groove respectively, so that the graphite ring completely covers the sleeve section. Then, install the crimp nut into the external thread section of the first mounting groove. After the crimp nut contacts the graphite ring, install the entire piston head into the cavity of the outer shell.

[0021] After installation, ensure that the pin at the end of the crimp nut matches and engages with the positioning groove in the inner cavity of the housing. Then, use a limit wrench on the hexagonal engagement mechanism to drive the piston head to rotate along its axis. Under the interaction of the pin and the positioning groove, as the piston head rotates, the crimp nut compresses and expands the graphite ring.

[0022] In this way, during the initial assembly stage, the crimp nut only contacts the graphite ring, at which point the graphite ring has not expanded, allowing the piston head to be smoothly inserted into the cavity of the outer shell. After the piston head is inserted into the cavity, the matching engagement of the pin block and the positioning groove enables radial positioning of the crimp nut. This allows the piston head to be rotated by the cooperation of the hexagonal positioning fixture and the hexagonal locking mechanism, which in turn causes the crimp nut to compress the graphite ring, forcing it to expand uniformly outwards. This direct expansion of the graphite ring within the cavity of the outer shell ensures more uniform expansion, guaranteeing the stability of the high-temperature seal and preventing delamination of the graphite ring under high-temperature sealing conditions caused by uneven expansion. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention.

[0024] Figure 2 This is a schematic diagram of the piston head of the present invention.

[0025] Figure 3 This is a schematic diagram of the crimp nut structure of the present invention.

[0026] Figure 4 This is a schematic diagram of the assembly structure of the piston head and the crimp nut of the present invention.

[0027] Among them, 1. outer shell; 2. crimp nut; 2-1. main body; 2-2. pin block; 3. graphite ring; 4. rubber ring; 5. piston head; 5-1. first mounting groove; 5-2. second mounting groove; 5-3. hexagonal snap-fit ​​mechanism; 6. molybdenum disulfide coating. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0031] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0032] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] Please refer to Figures 1 to 4As shown, a high-temperature dynamic sealing structure for a fire-working device is used for a cylindrical piston head 5. It includes a first mounting groove 5-1 coaxially disposed at the head end of the piston head 5 and a second mounting groove 5-2 coaxially disposed and spaced apart. One end of the first mounting groove 5-1 extends through the head end of the piston head 5.

[0035] The piston head 5 is located on the outer wall of the first mounting groove 5-1 and has an external thread section and a sleeve section. A graphite ring 3 is sleeved inside the sleeve section, and a crimp nut 2 is threadedly installed on the external thread section. A rubber ring 4 is sleeved inside the second mounting groove 5-2.

[0036] The piston head 5 is slidably assembled inside the outer shell 1, and the outer walls of the graphite ring 3 and the rubber ring 4 slide against the inner cavity of the outer shell 1.

[0037] The crimp nut 2 is used to keep the graphite ring 3 in an expanded state.

[0038] In this way, the piston head 5 is positioned with its tip facing the direction of high-temperature / high-pressure gas input, meaning the rubber ring 4 is closer to the air side than the graphite ring 3. This allows the positional fit between the graphite ring 3 and the rubber ring 4 to combine the high-temperature sealing performance of the graphite ring 3 with the room-temperature sealing protection of the rubber ring 4. In the room-temperature, non-operating state, the rubber ring 4's seal prevents external air and moisture from entering, preventing oxidation and moisture absorption failure of the internal graphite ring 3 and special coating during storage. In high-temperature operation, the rubber ring 4 fails due to high temperature, and the graphite ring 3 provides a dynamic seal. Furthermore, the compression nut 2 allows the graphite ring 3 to expand outwards, improving its sealing performance and ensuring reliable sealing of the actuator in high-temperature environments without altering the traditional piston shape. This prevents delamination failure of the graphite ring 3 during room-temperature storage, installation, and high-temperature use, thus solving the problem of actuator sealing failure in high-temperature environments.

[0039] Furthermore, to ensure uniform expansion of the graphite ring 3 and maintain its sealing performance, delamination failure of the graphite ring 3 must be avoided during use and storage. A pin block 2-2 is constructed on the end face of the main body 2-1 of the crimp nut 2 facing the inner cavity of the outer shell 1. A positioning groove matching the pin block 2-2 is constructed on the inner cavity end face of the outer shell 1. A hexagonal locking mechanism 5-3 is constructed around the outer wall of the tail end of the piston head 5 along its axis.

[0040] Specifically, the aforementioned pin 2-2 and positioning groove play a role in the assembly process of the graphite ring 3. Therefore, in this embodiment, an assembly method for the aforementioned high-temperature dynamic sealing structure of the fire-operating device is also provided. Its purpose is to prevent delamination of the graphite ring 3 during installation and to ensure that the graphite ring 3 remains in a uniform outward expansion state.

[0041] Specifically, first, the rubber ring 4 and the graphite ring 3 are respectively installed into the second mounting groove 5-2 and the first mounting groove 5-1, so that the graphite ring 3 completely covers the sleeve section. Then, the crimp nut 2 is installed into the external thread section of the first mounting groove 5-1. After the crimp nut 2 contacts the graphite ring 3, the entire piston head 5 is installed into the cavity of the outer shell 1.

[0042] After installation, ensure that the pin 2-2 at the end of the crimp nut 2 matches and engages with the positioning groove in the inner cavity of the outer shell 1. Then, use the limit wrench to act on the hexagonal engagement mechanism 5-3 to drive the piston head 5 to rotate along its axis. Under the interaction of the pin 2-2 and the positioning groove, as the piston head 5 rotates, the crimp nut 2 compresses and expands the graphite ring 3.

[0043] In this way, during the initial assembly stage, the crimp nut 2 only fits against the graphite ring 3. At this time, the graphite ring 3 has not expanded, and the piston head 5 can be smoothly installed into the cavity of the outer shell 1. After the piston head 5 is installed into the cavity, the crimp nut 2 can be radially positioned by the matching engagement of the pin block 2-2 and the positioning groove. Thus, after the piston head 5 is installed, the hexagonal positioning fixture and the hexagonal snap-fit ​​mechanism 5-3 cooperate to apply torque to the piston head 5, causing it to rotate. This causes the crimp nut to compress the graphite ring 3, forcing the graphite ring 3 to expand outward uniformly. In this way, allowing the graphite ring 3 to expand outward directly within the cavity of the outer shell 1 allows the expansion of the graphite ring 3 to be more uniform. This not only ensures the stability of the high-temperature seal but also avoids the delamination phenomenon of the graphite ring 3 under high-temperature sealing conditions caused by uneven expansion.

[0044] Furthermore, in order to ensure the uniform expansion of the graphite ring 3, the pin 2-2 is arranged with equal circumferential angles around the axis of the crimping nut 2, and the number and position of the positioning grooves correspond to and match the pin 2-2.

[0045] This allows the crimping nut 2 to move evenly along the axial direction, thus applying uniform pressure to the graphite ring 3. While ensuring uniform expansion of the graphite ring 3, the piston head 5 also ensures that the graphite ring 3 remains in a uniformly positioned state, allowing its expanded portion to fit evenly against the inner wall of the outer shell 1. This prevents delamination failure under high-temperature and harsh environments caused by uneven expansion of the graphite ring 3 during sliding friction with the inner wall of the cavity.

[0046] Furthermore, since the graphite ring 3 will expand outward after assembly, its axial length will decrease. To ensure that no gaps are formed between the inner wall of the crimp nut 2 and the outer wall of the sleeve section due to the axial shortening of the graphite ring 3 after the graphite ring 3 has expanded and assembled, thus affecting the sealing performance of the entire sealing structure under high temperature and high speed conditions, and to prevent the graphite ring 3 from delaminating or undergoing unexpected uneven outward expansion due to gaps caused by rapid changes in environmental conditions during use.

[0047] In this embodiment, the outer diameter of the threaded end of the external thread segment is the same as the outer diameter of the sleeve segment, and the axial length of the graphite ring 3 is greater than the axial length of the sleeve segment.

[0048] In this way, the former setting can significantly reduce the gap between the inner wall of the crimp nut 2 and the outer wall of the sleeve section after they overlap during the assembly process. Regarding the axial length of the graphite ring 3, the axial distance between the graphite ring 3 and the sleeve section differs by 0.1~0.2mm.

[0049] In this way, by increasing the compression shortening threshold through the graphite ring 3, the contact area between the crimp nut 2 and the sleeve section after installation is further reduced. This reduces the gap generated when the inner wall of the crimp nut 2 overlaps with the sleeve section.

[0050] Furthermore, the contact surfaces of the piston head 5 and the crimp nut 2 with the inner cavity of the outer casing 1 are coated with a molybdenum disulfide coating.

[0051] Furthermore, a molybdenum disulfide coating achieves self-lubrication and anti-seize on the sealing surface. At high temperatures, metal parts in contact can stick together, preventing the piston from unlocking properly. Adding a molybdenum disulfide coating between the sealing surfaces separates them, achieving both self-lubrication and preventing sticking. Molybdenum disulfide has a high operating temperature; when applied to the sealing surface, it provides self-lubrication under high-temperature conditions and prevents the metal parts on both sides of the sealing surface from sticking together at high temperatures, ensuring the normal unlocking operation of the piston head 5.

[0052] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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 high-temperature dynamic sealing structure for a fire-operated device, characterized in that, For a cylindrical piston head, a first mounting groove is coaxially disposed at the head end of the piston head and a second mounting groove is coaxially disposed and spaced apart, wherein one end of the first mounting groove extends through the head end of the piston head. The piston head is located on the outer wall of the first mounting groove and has an external thread section and a sleeve section. A graphite ring is sleeved inside the sleeve section, and a crimp nut is threadedly installed on the external thread section. A rubber ring is sleeved inside the second mounting groove. The piston head is slidably assembled inside the housing, and the outer walls of the graphite ring and the rubber ring slide against the inner cavity of the housing. The crimp nut is used to maintain the graphite ring in an expanded state.

2. The high-temperature dynamic sealing structure of the fire-working device according to claim 1, characterized in that, The main body of the crimp nut has a pin block on one end face facing the inner cavity of the housing, and the inner cavity end face of the housing has a positioning groove that matches the pin block. The outer wall of the tail end of the piston head has a hexagonal snap-fit ​​mechanism around its axis.

3. The high-temperature dynamic sealing structure of the fire-working device according to claim 2, characterized in that, The pin blocks are arranged with equal circumferential angles around the axis of the crimp nut, and the number and position of the positioning grooves correspond to and match the pin blocks.

4. The high-temperature dynamic sealing structure of the fire-working device according to claim 1, characterized in that, The outer diameter of the threaded end of the external thread section is the same as the outer diameter of the sleeve section, and the axial length of the graphite ring is greater than the axial length of the sleeve section.

5. The high-temperature dynamic sealing structure of the fire-working device according to claim 4, characterized in that, The axial distance between the graphite ring and the sleeve segment differs by 0.1~0.2mm.

6. A high-temperature dynamic sealing structure for a fire-operated device according to any one of claims 1 to 5, characterized in that, The contact surfaces of the piston head and the crimp nut with the inner cavity of the housing are coated with a molybdenum disulfide coating.

7. A method for assembling a high-temperature dynamic sealing structure for a fire-operated device as described in any one of claims 2 to 6, characterized in that, Insert the rubber ring and graphite ring into the second mounting groove and the first mounting groove respectively, so that the graphite ring completely covers the sleeve section. Insert the crimp nut into the external thread section of the first mounting groove. After the crimp nut contacts the graphite ring, insert the entire piston head into the cavity of the outer shell. After installation, ensure that the pin at the end of the crimp nut matches and engages with the positioning groove in the inner cavity of the housing. Then, use a limit wrench on the hexagonal engagement mechanism to drive the piston head to rotate along its axis. Under the interaction of the pin and the positioning groove, as the piston head rotates, the crimp nut compresses and expands the graphite ring.

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