Pipeline cold pressing connecting device for electric propulsion system

Abstract

The utility model discloses a pipeline cold-pressing connecting device for an electric propulsion system, which comprises a conduit cold-pressing joint, two corresponding stainless steel pipes are arranged at the left end and the right end in the conduit cold-pressing joint, sealing rings are sleeved on the surfaces of the stainless steel pipes, and a cold-pressing head is arranged on the surface of the conduit cold-pressing joint. By arranging the cold pressing heads, the cold pressing heads can be connected with a cold pressing clamp during actual operation, under the condition, the two cold pressing heads can be tightly pressed through the cold pressing clamp to enable the guide pipe cold pressing connector and the sealing ring to be connected to the stainless steel pipe in a pressing mode, and therefore dual-sealing effective connection is formed. Due to the fact that cold pressing connection is adopted, the size is small, use is convenient, and meanwhile blocking is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of cold-press connection, in particular to a pipeline cold-press connection device for an electric propulsion system. Background Art

[0002] Electric thrusters are an advanced propulsion product currently used in spacecraft. Different from conventional thrusters that use chemical working fluid reactions to generate thrust, electric thrusters use electrical energy to accelerate the working medium. They have the characteristics of low thrust, high specific impulse, and long service life. In particular, the specific impulse of electric thrusters is one order of magnitude higher than that of chemical thrusters. Accordingly, when the speed change requirement is the same, the mass of the working fluid used by electric thrusters is only one-tenth of that of chemical thrusters. A large part of the mass of a spacecraft is the working fluid carried for propulsion. The use of electric thrusters greatly saves the amount of working fluid and increases the payload loading capacity of the spacecraft.

[0003] At present, the working fluids used in electric thrusters are mostly inert gases that are easily ionized, such as xenon and krypton. Due to the limitation of the power supply capacity of the spacecraft, the thrust of electric thrusters is generally small, the required working fluid flow rate is also small, and the corresponding delivery pipeline diameter is also small. Taking the Hall thruster, which is relatively mature in electric thrusters, as an example, the working fluid flow rate of thrusters with input power ranging from hundreds of watts to kilowatts is tens to hundreds of sccm (standard volume milliliters per minute), and the outer diameter of its working fluid delivery pipeline is generally Φ2 to Φ4. Taking into account the assembly and use conditions of the thruster, stainless steel pipes are basically selected. The stainless steel pipe connection method is generally welding, mainly full-position argon arc welding of the catheter. Its advantages are good welding quality and reliable connection, but its disadvantages are large welding fixture volume, limited use space, and small diameter channel welds are easily blocked. For this reason, we propose a pipeline cold pressing connection device for electric propulsion systems. Utility Model Content

[0004] The technical problem to be solved by the utility model is to overcome the existing defects and provide a pipeline cold pressure connection device for an electric propulsion system. The cold pressure connection is not only small in size and convenient to use, but also avoids blockage, and can effectively solve the problems in the background technology.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A pipeline cold-pressing connection device for an electric propulsion system comprises a catheter cold-pressing joint, two corresponding stainless steel pipes are arranged at the left and right ends inside the catheter cold-pressing joint, sealing rings are sleeved on the surfaces of the stainless steel pipes, and a cold-pressing head is arranged on the surface of the catheter cold-pressing joint.

[0007] By setting the cold pressing head, it can be connected to the cold pressing clamp in actual operation. In this case, the two cold pressing heads can be pressed by the cold pressing clamp to press the catheter cold pressing joint and the sealing ring onto the stainless steel pipe, thereby forming an effective double-sealed connection.

[0008] Furthermore, the wall thickness of the catheter cold-pressed joint is smaller than the wall thickness of the stainless steel pipe connected thereto. The catheter cold-pressed joint may be an austenitic stainless steel pipe, and the stainless steel pipe is a small-diameter stainless steel pipe that matches the caliber of the catheter cold-pressed joint.

[0009] Furthermore, a raised step 1 is provided in the middle of the catheter cold-pressed joint for limiting the position of the catheter cold-pressed joint, and double sealing structures are provided on both sides of the raised step 1 inside the catheter cold-pressed joint. The main sealing structure is adjacent to the raised step 1, and the auxiliary sealing structure is away from the raised step 1. The sealing ring is located inside the auxiliary sealing structure, and the main sealing structure is smooth raised sharp teeth arranged on the inner wall of the catheter cold-pressed joint.

[0010] Furthermore, the height of the smooth raised tines is 0.3 mm and the angle is 120 degrees.

[0011] By setting a raised step in the middle of the catheter cold-pressed joint and setting a double sealing structure, a metal-to-metal hard seal will be formed with the stainless steel pipe after compression. This is the main sealing structure. The sealing ring sleeved on the surface of the stainless steel pipe forms a soft seal with the inner and outer catheter cold-pressed joints and the stainless steel pipe after being compressed. This is the auxiliary sealing structure. The hard seal is at the front of the medium in contact with the pipeline, and the soft seal of the sealing ring is in a redundant state at the rear.

[0012] Furthermore, the sealing ring is a polytetrafluoroethylene sealing ring with a rectangular cross section, and one end of the sealing ring away from the catheter cold joint is located inside the catheter cold joint and closer to the outside.

[0013] Furthermore, the surface roughness of the sealing ring is 1.6 μm and the thickness is 0.2 mm.

[0014] By placing the sealing ring at an outer side of the inner part of the catheter cold joint, it can be effectively prevented that the sealing ring falls out when the catheter cold joint is closed.

[0015] Furthermore, two upper and lower cold pressing heads are provided, and the upper and lower cold pressing heads cooperate with each other through the crimping hole. A raised step 2 is provided at one end of the lower cold pressing head, and a crimping hole is provided between the upper and lower cold pressing heads, and the crimping hole corresponds to the catheter crimping head.

[0016] The ferrule is made of chrome-vanadium steel, and its hardness is greater than 55HRC after heat treatment. The crimping hole is located at the center of the line connecting the catheter crimping joint and the crimping pliers mounting hole, which can make the force more uniform during crimping. When the upper and lower ferrules are closed during cold pressing, the hard sealing part forms a regular hexagon, which can prevent the stainless steel pipe from rotating in the catheter cold pressing joint and improve the tensile strength. The soft seal and the end part form a perfect circle, making the non-metallic seal and the end closing uniform.

[0017] Furthermore, the surface of the catheter cold-pressed joint is provided with three clamping positions, which correspond to the hard seal, soft seal and end closing parts respectively. There is a height difference between the three sections, which matches the deformation required for the hard seal, soft seal and end closing of the catheter cold-pressed joint respectively. After clamping, the sealing pairs of the hard seal and the soft seal can obtain suitable sealing pressure ratios.

[0018] The material of the catheter cold-pressed joint of the utility model is austenitic stainless steel, which has appropriate hardness and plasticity after solution heat treatment, and is not easy to crack when cold-pressed and deformed; the catheter cold-pressed joint is a thin-walled part, and the wall thickness is less than the stainless steel pipe it connects, so that the catheter cold-pressed joint is plastically deformed during cold pressing, while the stainless steel pipe is elastically deformed, and sealing stress can be formed between the two;

[0019] The utility model provides a double sealing structure for the cold-pressed conduit joint. The first is a hard seal between the inner wall of the cold-pressed conduit joint and the outer wall of the stainless steel pipe, and the other is a soft seal formed by the sealing ring under pressure.

[0020] The stainless steel pipe of the utility model is formed by cold drawing, so that the surface is smooth and clean, and it is easy to meet the requirements of hard sealing;

[0021] The sealing ring of the utility model is made of polytetrafluoroethylene, which has excellent temperature resistance and toughness;

[0022] The cold pressing head matched with the catheter cold pressing joint during crimping of the utility model is made of high-hardness alloy steel, and different profiles are set for the double sealing parts. The cross section of the cold pressing head at the hard sealing part is a regular hexagon, which can improve the tensile strength of the joint after cold pressing. The cross section of the cold pressing head at the soft sealing and catheter cold pressing joint end is circular, so that the deformation of the sealing ring and the closing end is more uniform and the sealing is more reliable.

[0023] The utility model provides positioning structures on the catheter cold-pressed joint and the cold-pressed head respectively. The inner wall of the middle of the catheter cold-pressed joint channel has a raised step one, and one end of the cold-pressed head has a raised step two. The raised step can accurately align the stainless steel pipe, the catheter cold-pressed joint and the cold-pressed head with each other during the cold-pressing operation, so that the sealing of the catheter cold-pressed joint is reliable after cold-pressing.

[0024] The cold pressing pliers used in the utility model for crimping are equipped with a ratchet structure, which can not only provide clamping during crimping assembly, but also control the cold pressing intensity and deformation degree, which is beneficial to the quality stability of the cold pressing operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0026] Figure 2 This is a cross-sectional view of a cold-pressed conduit joint of the utility model;

[0027] Figure 3 This is a schematic diagram of the cold pressing head structure of the utility model.

[0028] In the figure: 1 catheter cold press joint, 101 raised step 1, 2 sealing ring, 3 cold press head, 301 raised step 2, 4 stainless steel pipe. DETAILED DESCRIPTION

[0029] See also Figure 1-Figure 3 , a pipeline cold-pressed connection device for an electric propulsion system comprises a duct cold-pressed joint 1, two corresponding stainless steel pipes 4 are arranged at the left and right ends inside the duct cold-pressed joint 1, a sealing ring 2 is sleeved on the surface of the stainless steel pipe 4, a cold-pressed head 3 is arranged on the surface of the duct cold-pressed joint 1, the duct cold-pressed joint 1 can be an austenitic stainless steel pipe, the wall thickness of the duct cold-pressed joint 1 is less than the wall thickness of the stainless steel pipe 4 connected thereto, the stainless steel pipe 4 is a small-diameter stainless steel pipe that matches the caliber of the duct cold-pressed joint, a raised step 101 for limiting the duct cold-pressed joint 1 is arranged in the middle part of the duct cold-pressed joint 1, and double sealing structures are arranged on the left and right sides of the raised step 101 inside the duct cold-pressed joint 1, the main sealing structure is adjacent to the raised step 101, and the auxiliary sealing structure is far away from the raised step 101, the sealing ring 2 is located inside the auxiliary sealing structure, and the main sealing The structure is smooth raised sharp teeth arranged on the inner wall of the catheter cold-pressed joint 1, the height of the smooth raised sharp teeth is 0.3mm, the angle is 120 degrees, the sealing ring 2 is a polytetrafluoroethylene sealing ring with a rectangular cross-section, the surface roughness of the sealing ring is 1.6μm, and the thickness is 0.2mm. The end of the sealing ring 2 away from the catheter cold-pressed joint 1 is located on the inner side of the catheter cold-pressed joint 1. There are two upper and lower cold-pressed heads 3, and the upper and lower cold-pressed heads 3 cooperate with each other through the crimping hole. A raised step 2 301 is arranged at one end of the lower cold-pressed head 3, and a crimping hole is arranged between the upper and lower cold-pressed heads 3. The crimping hole corresponds to the catheter crimping joint 1. The cold-pressed head 3 is made of chrome-vanadium steel, and the hardness after heat treatment is greater than 55HRC. There are three clamping positions on the surface of the catheter cold-pressed joint 1, and the three clamping positions correspond to the hard seal, the soft seal and the end closing part, respectively. The hard seal refers to Figure 2 There is a bulge at the I magnification position, which, when pressed tightly, embeds into the outer surface of the stainless steel conduit, thus achieving a hard seal; soft seal refers to Figure 2 A sealing ring 2 is placed at the II enlarged position. Since the sealing ring is non-metallic, the seal at this location is called a soft seal; the end closing refers to the two ends of the catheter cold-pressed joint 1. When the cold joint 3 is tightened under the action of the cold-pressing pliers, a closing will be formed at both ends of the catheter cold-pressed joint 1, thereby realizing the sealing function). There is a height difference between the three sections, and the height difference matches the deformation required for the hard seal, soft seal and catheter cold-pressed joint end closing, respectively. After pressing, the sealing pairs of the hard seal and the soft seal can obtain a suitable sealing pressure ratio. The crimping hole is located at the center of the line connecting the catheter crimping joint 1 and the crimping pliers mounting hole, which can make the force more uniform during crimping. When cold pressing, after the upper and lower cold-pressing heads 3 are closed, the hard sealing part forms a regular hexagon, which can prevent the stainless steel pipe from rotating in the catheter cold-pressed joint and improve the tensile strength. The soft seal and the end part form a perfect circle, making the non-metallic seal The sealing and end closing are uniform. By placing the sealing ring 2 at the inner and outer position of the catheter cold joint 1, it can be effectively prevented that the sealing ring 2 falls out when the catheter cold joint 1 is closed. By setting a raised step 101 in the middle of the catheter cold-pressed joint 1, a double sealing structure is set at the same time so that after compression, a metal-to-metal hard seal is formed with the stainless steel pipe 4. This is the main sealing structure. The sealing ring 2 sleeved on the surface of the stainless steel pipe 4 forms a soft seal with the inner and outer catheter cold-pressed joints 1 and the stainless steel pipe 4 after being compressed. This is an auxiliary sealing structure. The hard seal is in the front part that contacts the medium in the pipeline, and the soft seal of the sealing ring is in a redundant state at the rear. By setting the cold pressing head 3, it can be connected to the cold pressing clamp in actual operation. In this case, the two cold pressing heads 3 can be pressed by the cold pressing clamp to press the catheter cold-pressed joint 1 and the sealing ring 2 onto the stainless steel pipe 4, thereby forming an effective connection with double sealing.

[0030] When in use, the cold pressing pliers are connected to the two cold pressing heads 3 using ordinary crimping pliers with a ratchet mechanism. First, the sealing ring 2 is put on the outside of the stainless steel pipe 4, and then the catheter cold pressing joint 1 is inserted between the upper and lower cold pressing heads 3, with one end close to the inner side of the positioning step of the lower cold pressing head 3 (see Figure 3 a), from the semicircular observation port of the cold head (see Figure 3 b) After checking that the position is in place, move a pair of crimping pliers handles to retract the upper and lower cold pressing heads 3 to gently clamp the catheter cold pressing joint 1, and the ratchet mechanism of the crimping pliers can automatically maintain this position; then insert the stainless steel tube 4 into the two inner holes on both sides of the catheter cold pressing joint 1 until the stainless steel tube 4 is close to the raised step 101 in the middle of the inner wall of the catheter cold pressing joint 1, and insert the sealing ring 2 to the bottom and pass through the semicircular observation port of the upper cold pressing head 3 (see Figure 3 b) Observe that the sealing ring 2 is completely inserted into the inner hole of the catheter cold press joint 1, and finally hold the crimping pliers handle tightly until the ratchet mechanism passes the limit and the cold press is in place, then release the crimping pliers, and the cold press connection operation of one end of the stainless steel tube 4 is completed. At this time, the cross section of the hard seal part is shown. Figure 3Middle AA, cross section of soft seal part Figure 3 Middle BB, the cross section of the conduit cold press fitting end is shown in Figure 3 In CC, cold pressing connection can be completed in this case.

[0031] In this embodiment, the cold pressing pliers with a ratchet mechanism are standard tools and can be purchased on the market without limitation on model and manufacturer.

Claims

1. A pipeline cold-press connection device for an electric propulsion system, comprising a pipe cold-press connector (1), characterized in that: Two corresponding stainless steel pipes (4) are arranged at the left and right ends of the interior of the catheter cold-pressed joint (1); a sealing ring (2) is sleeved on the surface of the stainless steel pipe (4); and a cold-pressed head (3) is arranged on the surface of the catheter cold-pressed joint (1).

2. The pipeline cold-press connection device for an electric propulsion system according to claim 1, characterized in that: The wall thickness of the catheter cold-pressed joint (1) is smaller than the wall thickness of the stainless steel pipe (4) connected thereto.

3. The pipeline cold-press connection device for an electric propulsion system according to claim 1, characterized in that: A raised step (101) is provided in the middle of the catheter cold-pressed joint (1), and double sealing structures are provided on both the left and right sides of the raised step (101) inside the catheter cold-pressed joint (1), wherein the main sealing structure is adjacent to the raised step (101), and the auxiliary sealing structure is away from the raised step (101), and the sealing ring (2) is located inside the auxiliary sealing structure, and the main sealing structure is a smooth raised sharp tooth provided on the inner wall of the catheter cold-pressed joint (1).

4. The pipeline cold-press connection device for an electric propulsion system according to claim 3, characterized in that: The height of the smooth raised sharp teeth is 0.3 mm and the angle is 120 degrees.

5. The pipeline cold-press connection device for an electric propulsion system according to claim 1, characterized in that: The sealing ring (2) is a polytetrafluoroethylene sealing ring with a rectangular cross section, and the end of the sealing ring (2) away from the catheter cold-pressed joint (1) is located inside the catheter cold-pressed joint (1) and closer to the outside.

6. The pipeline cold-press connection device for an electric propulsion system according to claim 5, characterized in that: The sealing ring (2) has a surface roughness of 1.6 μm and a thickness of 0.2 mm.

7. The pipeline cold-press connection device for an electric propulsion system according to claim 1, characterized in that: The cold pressing head (3) is provided with two upper and lower cold pressing heads (3), which cooperate with each other through a crimping hole, and one end of the lower cold pressing head (3) is provided with a raised step 2 (301) for limiting the position of the catheter cold pressing joint (1), and a crimping hole is provided between the upper and lower cold pressing heads (3), and the crimping hole corresponds to the catheter crimping joint (1).

8. The pipeline cold-press connection device for an electric propulsion system according to claim 1, characterized in that: The surface of the catheter cold-pressed joint (1) is provided with three pressing positions, which respectively correspond to the hard seal, the soft seal and the end closing part, and there is a height difference between the three sections, which respectively matches the deformation required for the hard seal, the soft seal and the end closing of the catheter cold-pressed joint.

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