A type of anti-loosening connection structure

Abstract

This application discloses an anti-loosening connection structure, relating to the field of main helium blower technology. The anti-loosening connection structure includes a stud and a nut. The first end of the stud is threadedly connected to a first connecting member, and the second end of the stud passes through a bolt hole in a second connecting member and is threadedly connected to the nut. Two first washers are provided between the second connecting member and the nut, fitted onto the stud. An inner cavity is provided between the two first washers, and a compression spring fitted onto the stud and abutting against the two first washers is located within the inner cavity. This application provides additional preload through the compression spring, which can compensate for the preload loss caused by thermal expansion of the stud, achieving elastic locking and ensuring the connection structure remains stable and reliable during long-term operation. By placing the compression spring within the inner cavity between the two first washers, the deformation of the compression spring can be constrained, preventing the compression spring from exceeding its load limit due to over-compression, thereby avoiding plastic deformation, damage, or failure of the compression spring.

Description

Technical Field

[0001] This application relates to the field of main helium blower technology, specifically to an anti-loosening connection structure for a main helium blower. Background Technology

[0002] In high-temperature gas-cooled reactor nuclear power plants, the main helium blower is a critical piece of equipment with a unique structure and operating environment. The main helium blower is a large, vertical, high-speed variable frequency unit installed inside the pressure vessel at the top of the steam generator, within the primary loop helium pressure chamber. This chamber experiences pressures as high as 7 MPa and temperatures reaching 250°C. Furthermore, the main helium blower's working chamber is connected to the chamber containing the drive motor, while the temperature of the drive motor's chamber is only 65°C, creating a significant temperature difference between the two.

[0003] Fasteners play a crucial role in the safety equipment of nuclear power plants. They are primarily responsible for key functions such as pressure sealing, component connection, and support and fixation, and their quality and performance directly affect the safe operation of the nuclear power plant. However, due to the special operating environment of the main helium blower, during the initial startup phase, fasteners such as bolts or studs heat up rapidly and elongate due to thermal expansion, leading to a decrease in their preload. As operating time increases, nuts are prone to loosening during operation.

[0004] Therefore, existing fasteners are insufficient to meet the reliable anti-loosening performance required for bolt or stud connections in the nuclear power field when facing the complex operating environment of the main helium blower. This deficiency poses a potential risk to the safe operation of the main helium blower. Utility Model Content

[0005] The purpose of this application is to provide an anti-loosening connection structure to solve the problem of the nut of the main helium blower becoming loose during operation.

[0006] The technical solution adopted by this application to solve its technical problem is:

[0007] An anti-loosening connection structure includes a stud and a nut, wherein a first end of the stud is threadedly connected to a first connector, and a second end of the stud passes through a bolt hole of a second connector and is threadedly connected to the nut.

[0008] The second connector is provided with two first washers sleeved on the stud between the second connector and the nut. An inner cavity is provided between the two first washers. A compression spring is provided in the inner cavity, which is sleeved on the stud and abuts against the two first washers.

[0009] Furthermore, the surfaces between the two first washers are provided with grooves, and the two grooves are joined together to form the embedded cavity.

[0010] Furthermore, the compression spring comprises at least two disc springs.

[0011] Furthermore, the stud includes a first external thread section, a tension section, a smooth section, a second external thread section, and a screwing head arranged along its axial direction. The first external thread section is connected to the first connector, the first washer and the compression spring 6 are sleeved on the smooth section, and the nut is connected to the second external thread section.

[0012] Furthermore, the surface of the smooth segment has a nitrided layer.

[0013] Furthermore, at least two nuts are connected to the second external threaded section.

[0014] Furthermore, the nut is provided with a protective cover on the side away from the second connector that is threadedly connected to the stud.

[0015] Furthermore, the protective cover includes a polygonal prism and a cylinder coaxially connected, and the end of the cylinder away from the polygonal prism is provided with a second internal threaded hole, which is threadedly connected to the stud.

[0016] Furthermore, a second washer is provided between the protective cover and the nut, which is fitted onto the stud.

[0017] Furthermore, the surface of the first gasket has a nitrided layer.

[0018] The beneficial effects of this application are:

[0019] The anti-loosening connection structure provided in this application embodiment uses two first washers between the second connector and the nut, and a compression spring installed in the cavity between the two first washers. When the nut is tightened, the compression spring is compressed and stores elastic potential energy, thereby providing an additional axial preload. When the preload decreases due to thermal expansion of the stud during the initial start-up of the main helium blower, the compression spring can promptly reset to compensate for the loss of preload caused by thermal expansion, achieving elastic locking. This effectively ensures the strength and stability of the connection structure and fundamentally prevents the nut from loosening due to the thermal expansion of the stud during operation. By placing the compression spring in the cavity between the two first washers, the deformation of the compression spring can be constrained, ensuring that its additional preload is always within a controllable range. This prevents the compression spring from exceeding its load limit due to over-compression, thus avoiding plastic deformation, damage, or failure of the compression spring, extending the service life of the entire connection structure, and improving its reliability under complex working conditions. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the anti-loosening connection structure provided in the embodiments of this application;

[0022] Figure 2 This is a schematic diagram of the stud structure;

[0023] Figure 3 This is a schematic diagram of the structure of the first washer;

[0024] Figure 4 This is a schematic diagram of the protective cover.

[0025] Figure label:

[0026] 1-Protective cover; 11-Polygonal prism; 12-Cylinder; 121-Second internal threaded hole;

[0027] 2-Stud; 21-First external thread section; 22-Tension section; 23-Smooth section; 24-Second external thread section; 25-Screwing head;

[0028] 3-Second washer;

[0029] 4-Nuts;

[0030] 5-First washer; 51-Inner cavity; 52-Groove;

[0031] 6-Compression spring;

[0032] 7-Second connector; 71-Bolt hole;

[0033] 8-First connector; 81-First internal threaded hole. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0035] In the description of this application, the terms "upper," "lower," "left," "right," "front," "rear," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application 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. Therefore, they should not be construed as limitations on this application. Unless otherwise specified, the above-mentioned orientational descriptions can be flexibly set in actual application, provided that the relative positional relationships shown in the accompanying drawings are satisfied.

[0036] See Figure 1 This application provides an anti-loosening connection structure, including a stud 2 and a nut 4. The first end of the stud 2 is threadedly connected to the first connector 8, and the second end of the stud 2 passes through the bolt hole 71 of the second connector 7 and is threadedly connected to the nut 4. Two first washers 5 are provided between the second connector 7 and the nut 4, which are sleeved on the stud 2. An inner cavity 51 is provided between the two first washers 5, and a compression spring 6 is provided in the inner cavity 51, which is sleeved on the stud 2 and abuts against the two first washers 5.

[0037] See Figure 1 The first connecting member 8 and the second connecting member 7 are two components of the main helium blower. The top of the first connecting member 8 has a first sealing surface, and the bottom of the second connecting member 7 has a second sealing surface. The first sealing surface of the first connecting member 8 and the second sealing surface of the second connecting member 7 are sealed together and connected by the anti-loosening connection structure of this application. The first connecting member 8 is provided with a first internal threaded hole 81 for threaded connection with the first end of the stud 2, and the second connecting member 7 is provided with a bolt hole 71 for the stud 2 to pass through.

[0038] The anti-loosening connection structure provided in this application embodiment involves setting two first washers 5 between the second connector 7 and the nut 4, and installing a compression spring 6 in the inner cavity 51 between the two first washers 5. When the nut 4 is tightened, the compression spring 6 is compressed and stores elastic potential energy, thereby providing an additional axial preload. When the preload of the stud 2 decreases due to thermal expansion during the initial start-up of the main helium blower, the compression spring 6 can promptly reset to compensate for the loss of preload caused by the thermal expansion of the stud 2, achieving elastic locking. This effectively ensures the strength and stability of the connection structure and fundamentally avoids the phenomenon of the nut 4 loosening due to the thermal expansion of the stud during operation.

[0039] The anti-loosening connection structure provided in this application embodiment, by placing the compression spring 6 within the embedded cavity 51 between the two first washers 5, can constrain the deformation of the compression spring 6, ensuring that its additional preload is always within a controllable range. This prevents the compression spring 6 from exceeding its load limit due to over-compression, thereby avoiding plastic deformation, damage, or failure of the compression spring 6, extending the service life of the entire connection structure, and improving its reliability under complex working conditions. Specifically, when the nut 4 is not tightened, there is a gap between the two first washers 5. After tightening the nut 4, the two first washers 5 are pressed together, causing the compression spring 6 to be compressed and store elastic potential energy, thereby providing an axial additional preload while preventing over-compression of the compression spring 6. Furthermore, by controlling the height difference between the embedded cavity 51 and the compression spring 6, different axial additional preloads can be provided by the compression spring 6.

[0040] In some embodiments, see Figure 2 The surfaces between the two first washers 5 are each provided with a groove 52, and the two grooves 52 fit together to form an embedded cavity 51. Alternatively, in other embodiments, the surface between the two first washers 5 may have a groove on only one of the surfaces, and this groove fits together with the surface of the other to form the embedded cavity 51. To improve the wear resistance of the first washers 5, the surface of the first washers 5 has a nitrided layer. See also... Figure 2 After the groove 52 on the first washer 5 is processed, the surface of the first washer 5 is nitrided to form a high-hardness nitrided layer on the surface of the first washer 5, which significantly improves the wear resistance of the first washer 5.

[0041] In some embodiments, see Figure 1 The compression spring 6 comprises at least two disc springs. Correspondingly, disc springs, also called butterfly springs, are a type of non-linear compression spring with a unique structure. Their shape resembles a shallow bowl or saucer, giving them high stiffness and the ability to withstand large loads with small deformations, making them suitable for applications with limited axial space. The at least two disc springs can be arranged in a paired or stacked configuration. When at least two disc springs are stacked, the more disc springs there are, the greater the load for the same deformation. The thicknesses of the at least two disc springs can be the same or different. Of course, in other embodiments, the compression spring 6 can also be a helical spring capable of withstanding axial pressure; no specific limitation is made here.

[0042] In some embodiments, see Figure 3 The stud 2 includes a first external thread section 21, a tension section 22, a smooth section 23, a second external thread section 24 and a screw head 25 arranged along its axial direction. The first external thread section 21 is connected to the first connector 8. The first washer 5 and the compression spring 6 are sleeved on the smooth section 23. The nut 4 is connected to the second external thread section 24.

[0043] Specifically, the first external thread section 21 is used for threaded connection with the first internal thread hole 81, and the tension section 22 is used to be disposed within the bolt hole 71. The outer diameter of the smooth section 23 is larger than the outer diameter of other parts of the stud 2, but smaller than the inner diameter of the bolt hole 71. A first washer 5 and a compression spring 6 are fitted on the smooth section 23. To improve the wear resistance of the smooth section 23, a nitrided layer is formed on the surface of the smooth section 23 through a nitriding process. The second external thread section 24 is used for threaded connection with the nut 4. To improve the reliability of the connection, at least two nuts 4 are connected to the second external thread section 24. By setting at least two nuts 4, a multiple anti-loosening mechanism can be formed; wherein, the first nut 4 is used to provide the main preload, while the second nut 4 can further lock the first nut 4, preventing it from loosening due to vibration or temperature changes, significantly improving the anti-loosening reliability of the connection. The screw head 25 is a polygonal cylinder, and its diagonal dimension is smaller than the outer diameter of the second external thread section 24. By providing a screwdriver 25 for use with a wrench to tighten the stud 2, the stud 2 is threadedly connected to the first connector 8.

[0044] In some embodiments, see Figure 1 A protective cover 1, threadedly connected to the stud 2, is provided on the side of the nut 4 away from the second connector 7. Accordingly, the protective cover 1 protects the second external thread section 24 of the stud 2 and also provides additional constraint to the nut 4 by pressing against it. See also Figure 1 A second washer 3 is provided between the protective cover 1 and the nut 4, and is fitted onto the stud 2. Accordingly, by providing the second washer 3, the friction between the nut 4 and the protective cover 1 can be reduced, the risk of wear can be reduced, and the preload force of the protective cover 1 on the nut 4 can be distributed to prevent the nut 4 from deforming or being damaged due to excessive local stress.

[0045] For example, see Figure 4 The protective cover 1 includes a polygonal prism 11 and a cylinder 12 coaxially connected. The end of the cylinder 12 furthest from the polygonal prism 11 has a second internal threaded hole 121, which is threadedly connected to the stud 2. Accordingly, the polygonal prism 11 is used to engage with a wrench to tighten the protective cover 1; the cylinder 12, with its second internal threaded hole 121 at one end, protects the second external threaded section 24 of the stud 2 after the second internal threaded hole 121 is threadedly connected to the second external threaded section 24 of the stud 2.

[0046] See Figure 1 The process of connecting the first connector 8 and the second connector 7 together using the anti-loosening connection structure provided in this application embodiment is as follows:

[0047] Assemble the first connector 8 and the second connector 7 together, aligning the bolt hole 71 of the second connector 7 with the first internal thread hole 81 of the first connector 8; pass the lower end of the stud 2 through the bolt hole 71 and insert it into the first internal thread hole 81, using a wrench to drive the tightening head 25 to rotate, so that the first external thread section 21 of the stud 2 is threadedly connected to the first internal thread hole 81 and reaches a fixed distance. At this time, the tension section 22 of the stud 2 is located inside the bolt hole 71, while the smooth section 23 is located outside the bolt hole 71; then proceed sequentially... The first washer 5, the compression spring 6, and the second washer 5 are fitted onto the smooth section 23 of the stud 2 from the upper end of the stud 2, so that the compression spring 6 is installed in the inner cavity 51 between the two first washers 5; the two nuts 4 are threaded onto the second external thread section 24 of the stud 2, and the nuts 4 are tightened using a hydraulic tensioner until the preload of the stud 2 meets the requirements; the second washer 3 is fitted onto the second external thread section 24 of the stud 2, and then the protective cover 1 is threaded onto the second external thread section 24 of the stud 2.

[0048] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A non-loosening connection structure, comprising a stud (2) and a nut (4), wherein the first end of the stud (2) is threadedly connected to a first connector (8), and the second end of the stud (2) passes through the bolt hole (71) of the second connector (7) and is threadedly connected to the nut (4); characterized in that The second connector (7) and the nut (4) are provided with two first washers (5) sleeved on the stud (2), and an inner cavity (51) is provided between the two first washers (5). A compression spring (6) sleeved on the stud (2) and abutting against the two first washers (5) is provided in the inner cavity (51).

2. The anti-loosening connection structure according to claim 1, characterized in that, The surfaces between the two first washers (5) are provided with grooves (52), and the two grooves (52) are joined together to form the inner cavity (51).

3. The anti-loosening connection structure according to claim 1, characterized in that, The compression spring (6) comprises at least two disc springs.

4. The anti-loosening connection structure according to claim 1, characterized in that, The stud (2) includes a first external thread section (21), a tension section (22), a smooth section (23), a second external thread section (24), and a screw head (25) arranged along its axial direction. The first external thread section (21) is connected to the first connector (8). The first washer (5) and the compression spring (6) are sleeved on the smooth section (23). The nut (4) is connected to the second external thread section (24).

5. The anti-loosening connection structure according to claim 4, characterized in that, The surface of the smooth segment (23) has a nitrided layer.

6. The anti-loosening connection structure according to claim 4, characterized in that, At least two of the nuts (4) are connected to the second external thread section (24).

7. The anti-loosening connection structure according to claim 1, 2, 3, 4, 5 or 6, characterized in that, The nut (4) is provided with a protective cover (1) on the side away from the second connector (7) that is threadedly connected to the stud (2).

8. The anti-loosening connection structure according to claim 7, characterized in that, The protective cover (1) includes a polygonal prism (11) and a cylinder (12) connected coaxially. The cylinder (12) has a second internal threaded hole (121) at one end away from the polygonal prism (11). The second internal threaded hole (121) is threadedly connected to the stud (2).

9. The anti-loosening connection structure according to claim 7, characterized in that, A second washer (3) is provided between the protective cover (1) and the nut (4) and fitted onto the stud (2).

10. The anti-loosening connection structure according to claim 1, characterized in that, The surface of the first gasket (5) has a nitrided layer.

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