High-temperature dynamic sealing structure of pyrotechnic actuating device and assembly method of high-temperature dynamic sealing structure

Abstract

The invention discloses a high-temperature dynamic sealing structure of an initiating explosive actuating device and an assembling method, and relates to the technical field of high-temperature sealing of initiating explosive actuating mechanisms. The mounting structure is used for a columnar piston head and comprises a first mounting groove coaxially formed in the head end of the piston head and second mounting grooves coaxially formed in a spaced mode, and one end of the first mounting groove penetrates through the head end of the piston head; an external thread section and a sleeving section are constructed at the position, located on the outer wall of the first mounting groove, of the piston head, a graphite ring is arranged in the sleeving section in a sleeving mode, a crimping nut is installed on the external thread section in a threaded mode, and a rubber ring is arranged in the second mounting groove in a sleeving mode; the piston head is assembled in the shell in a sliding mode, and the outer walls of the graphite ring and the rubber ring abut against an inner cavity of the shell in a sliding mode. The crimping nut is used for keeping the external expansion state of the graphite ring; therefore, the purposes that high-temperature dynamic sealing is carried out by adapting to the pyrotechnic actuating device, and existing normal-temperature dynamic sealing can be replaced in situ are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature sealing of a fire-operated actuator, in particular to a high-temperature dynamic sealing structure and an assembly method of a fire-operated actuator. Background Art

[0002] Reliable dynamic sealing is key to 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 focuses primarily on ceramic disc seals and braided fiber rope seals. However, these seals are used in environments significantly different from those used in pyrotechnic devices and are therefore unsuitable for the dynamic sealing requirements of pyrotechnic devices. In addition to the aforementioned new high-temperature seals, flexible graphite has found widespread application in high-temperature sealing applications due to its advantages, including self-lubrication, high thermal conductivity, and chemical stability. However, graphite itself is brittle and prone to delamination during installation. It is also susceptible to oxidation and moisture absorption during long-term storage, leading to its failure. Existing dynamic seals for pyrotechnic devices are not heat-resistant, and heat-resistant seals differ significantly from existing sealing structures during use, requiring complete new design and verification. These seals are no longer suitable for the development of the next generation of hypersonic weapons.

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

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

[0006] In order to achieve the above object, the present invention adopts the following technical means: A high-temperature dynamic sealing structure for a pyrotechnic actuator, for a cylindrical piston head, comprising a first mounting groove coaxially arranged at the head end of the piston head and second mounting grooves coaxially arranged and spaced apart, one end of the first mounting groove being arranged through the head end of the piston head; The outer wall of the piston head located in the first mounting groove is constructed with an external thread section and a sleeve section, a graphite ring is sleeved in the sleeve section, a compression nut is threadedly installed in the external thread section, and a rubber ring is sleeved in the head of the second mounting groove; The piston head is slidably assembled in the housing, and the outer walls of the graphite ring and the rubber ring are in sliding contact with the inner cavity of the housing; The compression nut is used to keep the graphite ring in an outwardly expanded state.

[0007] Preferably, the main body of the compression nut is provided with a pin block on one end face facing the inner cavity of the shell, the inner cavity end face of the shell is provided with a positioning groove matching the pin block, and the outer wall of the tail end of the piston head is provided with a hexagonal clamping mechanism around its axis.

[0008] Furthermore, the pin block is arranged around the axis of the compression nut at an equal circumferential angle, and the number and position of the positioning grooves correspond to those of the pin block.

[0009] Furthermore, the outer diameter of the threaded end of the external threaded 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.

[0010] Furthermore, the axial distance between the graphite ring and the sleeve section differs by 0.1 to 0.2 mm.

[0011] Furthermore, the contact surfaces of the piston head and the compression nut with the inner cavity of the housing are coated with a molybdenum disulfide coating.

[0012] The high-temperature dynamic sealing structure of a fire-operated actuator according to the present invention has the following beneficial effects in sealing operations of the fire-operated actuator in a high-temperature environment above 600°C: The piston head is positioned toward the high-temperature / high-pressure gas input, placing the rubber ring closer to the air side than the graphite ring. This allows the graphite ring and rubber ring to be positioned in a coordinated manner, combining the high-temperature sealing performance of the graphite ring with the sealing protection of the rubber ring at room temperature. When not in operation at room temperature, the rubber ring seals the entire sealing structure, preventing the ingress of air and moisture, and 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 heat, and the graphite ring provides the dynamic seal at high temperatures. Furthermore, the compression nut allows the graphite ring to expand outward, improving its sealing performance while ensuring reliable sealing of the actuator in high-temperature environments without changing the traditional piston shape. This prevents delamination of the graphite ring during storage, installation, and high-temperature operation, thus resolving the issue of actuator seal failure in high-temperature environments.

[0013] Furthermore, the present invention provides a method for assembling the aforementioned high-temperature dynamic seal structure for a fire-operated actuator. The method aims to prevent delamination of the graphite ring during installation and ensure that the graphite ring is in a uniform outward expansion state.

[0014] In order to achieve the above-mentioned object, the assembly method of the present invention is specifically as follows: First, install the rubber ring and graphite ring into the second installation groove and the first installation groove respectively, so that the graphite ring completely covers the sleeve section. Install the compression nut into the external thread section of the first installation groove. After the compression nut contacts the graphite ring, install the entire piston head into the cavity of the housing. After installation, ensure that the pin block at the end of the compression nut matches the positioning groove set in the inner cavity of the shell, and then use the limit wrench to act on the hexagonal clamping mechanism to drive the piston head to rotate along its axis. Under the interaction of the pin block and the positioning groove, as the piston head rotates, the compression nut is used to compress and expand the graphite ring.

[0015] In this way, at the initial stage of assembly, the compression nut only fits against the graphite ring. At this time, the graphite ring has not expanded, and the piston head can be smoothly installed into the cavity of the housing. After the piston head is installed in the cavity, the compression nut can be radially positioned by matching the pin block and the positioning groove. As a result, after the piston head is installed, the hexagonal positioning tool and the hexagonal clamping mechanism are combined to apply torque to the piston head to rotate it, thereby causing the compression nut to squeeze the graphite ring, forcing the graphite ring to expand evenly. In this way, directly allowing the graphite ring to expand outward in the cavity of the housing can make the expansion of the graphite ring more uniform, which not only ensures the stability of high-temperature sealing, but also avoids the stratification of the graphite ring under high-temperature sealing conditions due to uneven expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention.

[0017] Figure 2 It is a structural schematic diagram of the piston head of the present invention.

[0018] Figure 3 It is a schematic diagram of the structure of the compression nut of the present invention.

[0019] Figure 4 It is a schematic diagram of the assembly structure of the piston head and the compression nut of the present invention.

[0020] Among them, 1. Shell; 2. Press-fit 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 clamping mechanism; 6. Molybdenum disulfide coating. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0023] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other.

[0024] 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.

[0025] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is typically placed when in use, or are the orientations or positional relationships commonly understood by those skilled in the art. These terms are intended only to facilitate the description of the present invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0027] Please refer to Figures 1 to 4As shown, a high-temperature dynamic sealing structure of a pyrotechnic device is used for a cylindrical piston head 5, comprising a first mounting groove 5-1 coaxially arranged at the head end of the piston head 5 and second mounting grooves 5-2 coaxially arranged and spaced apart. One end of the first mounting groove 5-1 is provided through the head end of the piston head 5; The outer wall of the piston head 5 located in the first installation groove 5-1 is constructed with an external thread section and a sleeve section. A graphite ring 3 is sleeved in the sleeve section. A compression nut 2 is threadedly installed in the external thread section. A rubber ring 4 is sleeved in the head of the second installation groove 5-2. The piston head 5 is slidably assembled in the housing 1, and the outer walls of the graphite ring 3 and the rubber ring 4 are in sliding contact with the inner cavity of the housing 1; The compression nut 2 is used to keep the graphite ring 3 in an outwardly expanded state.

[0028] In this way, the tip of the piston head 5 is positioned toward the high-temperature / high-pressure gas input direction, placing the rubber ring 4 closer to the air side than the graphite ring 3. This coordinated positioning of the graphite ring 3 and the rubber ring 4 ensures both the high-temperature sealing performance of the graphite ring 3 and the sealing protection of the rubber ring 4 at room temperature. When not in operation at room temperature, the entire sealing structure, sealed by the rubber ring 4, prevents the ingress of external air and moisture, preventing oxidation and moisture absorption failure of the graphite ring 3 and the special coating within during storage. During high-temperature operation, the rubber ring 4 fails due to the high temperature, and the graphite ring 3 provides the dynamic seal at high temperatures. Furthermore, the compression nut 2 allows the graphite ring 3 to expand outward, improving its sealing performance while ensuring reliable sealing of the actuator in high-temperature environments without changing the conventional piston shape. This prevents delamination of the graphite ring 3 during storage, installation, and high-temperature operation, thus resolving the issue of actuator sealing failure in high-temperature environments.

[0029] Furthermore, to ensure uniform expansion of the graphite ring 3 and prevent delamination during use and storage while maintaining tightness, the main body 2-1 of the compression nut 2 is provided with a pin block 2-2 on one end thereof facing the inner cavity of the housing 1. A positioning groove matching the pin block 2-2 is provided on the inner cavity end of the housing 1. A hexagonal snap-fit ​​mechanism 5-3 is provided on the outer wall of the rear end of the piston head 5 around its axis.

[0030] Specifically, the aforementioned pin block 2-2 and positioning groove play a role in the assembly process of the graphite ring 3. Therefore, this embodiment also provides an assembly method for the aforementioned high-temperature dynamic seal structure of a pyrotechnic device. This method aims to prevent delamination of the graphite ring 3 during installation and ensure that the graphite ring 3 maintains a uniform outward expansion state.

[0031] Specifically, first, install the rubber ring 4 and the graphite ring 3 into the second installation groove 5-2 and the first installation groove 5-1 respectively, so that the graphite ring 3 completely covers the sleeve section, and install the compression nut 2 into the external thread section of the first installation groove 5-1. After the compression nut 2 contacts the graphite ring 3, install the entire piston head 5 into the cavity of the housing 1; After installation, ensure that the pin block 2-2 at the end of the compression nut 2 matches the positioning groove set in the inner cavity of the shell 1, and then use the limit wrench to act on the hexagonal clamping mechanism 5-3 to drive the piston head 5 to rotate along its axis. Under the interaction between the pin block 2-2 and the positioning groove, as the piston head 5 rotates, the compression nut 2 is used to compress and expand the graphite ring 3.

[0032] In this way, at the initial stage of assembly, the compression 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 in the cavity of the housing 1. After the piston head 5 is installed in the cavity, the compression nut 2 can be radially positioned by using the matching snap-fitting of the pin block 2-2 and the positioning groove. As a result, after the piston head 5 is installed, the hexagonal positioning fixture and the hexagonal snap-fitting mechanism 5-3 cooperate to apply torque to the piston head 5 to rotate it, thereby causing the compression nut to squeeze the graphite ring 3, forcing the graphite ring 3 to expand evenly. In this way, directly allowing the graphite ring 3 to expand outward in the cavity of the housing 1 can make the expansion of the graphite ring 3 more uniform, which not only ensures the stability of the high-temperature seal, but also avoids the occurrence of stratification of the graphite ring 3 in the high-temperature sealing state due to uneven expansion.

[0033] Furthermore, in order to ensure uniform expansion of the graphite ring 3, the pin block 2-2 is arranged at an equal circumferential angle around the axis of the compression nut 2, and the number and position of the positioning grooves correspond to the pin block 2-2.

[0034] This allows the compression nut 2 to move along the axis in a balanced manner, exerting a uniform compressive force on the graphite ring 3. This ensures uniform expansion of the graphite ring 3 and, during the movement of the piston head 5, ensures that the graphite ring 3 remains evenly positioned, allowing the expanded portion to evenly adhere to the inner wall of the housing 1. This prevents uneven expansion of the graphite ring 3 during use, which can lead to sliding friction with the inner wall of the inner cavity and delamination failure in harsh high-temperature environments.

[0035] Furthermore, since the graphite ring 3 expands outward after assembly, the axial length of the graphite ring 3 decreases. To ensure that after the graphite ring 3 is expanded and assembled, there is no gap between the inner wall of the compression nut 2 and the outer wall of the sleeve section due to the axial shortening of the graphite ring 3, which would affect the sealing performance of the entire sealing structure under high temperature and high speed conditions, and to avoid the gap caused by the rapid change of environmental conditions during use, which would cause the graphite ring 3 to delaminate and unexpected uneven expansion.

[0036] In this embodiment, the outer diameter of the threaded end of the external threaded section is the same as the outer diameter of the sleeve section, and the axial length of the graphite ring 3 is greater than the axial length of the sleeve section.

[0037] In this way, the former setting can significantly reduce the gap between the inner wall of the compression nut 2 and the outer wall of the sleeve section after the compression nut 2 is overlapped with the sleeve section during assembly. As for the axial length of the graphite ring 3, the axial distance between the graphite ring 3 and the sleeve section differs by 0.1-0.2 mm.

[0038] In this way, the threshold of compression shortening is increased by the graphite ring 3, and the contact area between the compression nut 2 and the sleeve section is further reduced after installation, thereby reducing the gap generated after the inner wall of the compression nut 2 and the sleeve section overlap.

[0039] Furthermore, the contact surfaces of the piston head 5 and the compression nut 2 with the inner cavity of the housing 1 are coated with a molybdenum disulfide coating.

[0040] The molybdenum disulfide coating further achieves self-lubrication and anti-seizure properties on the sealing surface. At high temperatures, contacting metal parts can adhere to each other, preventing the piston from unlocking properly. Adding a layer of molybdenum disulfide coating between the contacting sealing surfaces separates them, achieving both self-lubrication and adhesion prevention. Molybdenum disulfide, which operates at high temperatures, coats the sealing surface, achieving both self-lubrication and adhesion prevention at high temperatures, ensuring proper unlocking of the piston head 5.

[0041] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-temperature dynamic sealing structure for a fire-operated actuator, characterized in that: For a cylindrical piston head, comprising a first mounting groove coaxially arranged at the head end of the piston head and a second mounting groove coaxially arranged and spaced apart, wherein one end of the first mounting groove is arranged through the head end of the piston head; The outer wall of the piston head located in the first mounting groove is constructed with an external thread section and a sleeve section, a graphite ring is sleeved in the sleeve section, a compression nut is threadedly installed in the external thread section, and a rubber ring is sleeved in the head of the second mounting groove; The piston head is slidably assembled in the housing, and the outer walls of the graphite ring and the rubber ring are in sliding contact with the inner cavity of the housing; The compression nut is used to keep the graphite ring in an outwardly expanded state.

2. A high-temperature dynamic sealing structure for a fire-operated actuator according to claim 1, characterized in that: A pin block is constructed on one end face of the main body of the compression nut facing the inner cavity of the shell, a positioning groove matching the pin block is constructed on the inner cavity end face of the shell, and a hexagonal clamping mechanism is constructed on the outer wall of the tail end of the piston head around its axis.

3. A high-temperature dynamic sealing structure for a fire-operated actuator according to claim 2, characterized in that: The pin block is arranged around the axis of the compression nut at equal circumferential angles, and the number and positions of the positioning grooves correspond to those of the pin block.

4. A high-temperature dynamic sealing structure for a fire-operated actuator according to claim 1, characterized in that: The outer diameter of the threaded end of the external threaded 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. A high-temperature dynamic sealing structure for a fire-operated actuator according to claim 4, characterized in that: The axial distance between the graphite ring and the sleeve section differs by 0.1 to 0.2 mm.

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

7. An assembly method for a high-temperature dynamic sealing structure of a fire-operated actuator according to any one of claims 2 to 6, characterized in that: Install the rubber ring and graphite ring into the second installation groove and the first installation groove respectively, so that the graphite ring completely covers the sleeve section, and install the compression nut into the external thread section of the first installation groove. After the compression nut contacts the graphite ring, install the entire piston head into the cavity of the housing; After installation, ensure that the pin block at the end of the compression nut matches the positioning groove set in the inner cavity of the shell, and then use the limit wrench to act on the hexagonal clamping mechanism to drive the piston head to rotate along its axis. Under the interaction of the pin block and the positioning groove, as the piston head rotates, the compression nut is used to compress and expand the graphite ring.

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