Screw anti-loosening structure of fuel cell and fuel cell

Abstract

The invention discloses a screw anti-loosening structure of a fuel cell and the fuel cell. The screw anti-loosening structure comprises a rotation limiting unit and an anti-loosening torque unit, the square key is embedded into the anode end plate key groove and the screw rod key groove at the same time to directly lock the axial rotation of the screw rod relative to the anode end plate, so that the reverse loosening of a thread pair between the screw rod and the cathode end plate is inhibited. The anti-loosening torque unit comprises a torsion spring, a torsion ring and a spline, one end of the torsion spring is fixed on the anode end plate, and the other end is connected with the spline through the torsion ring; continuous elastic torque is generated through the pre-tightening torsion spring, and the torque is transmitted through the spline and is finally converted into continuous anti-loosening torque which acts on the tightening nut and has the same direction as the tightening direction so as to confront the anti-loosening trend of a thread pair between the nut and the screw rod. And all components can be detached and reused while bidirectional reliable looseness prevention is realized, the advantage of convenience in maintenance of screw packaging is completely reserved, and the long-term reliability, stability and service life of the fuel cell screw pile under complex working conditions are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of fuel cell structural design technology, specifically to a screw anti-loosening structure for a fuel cell and the fuel cell itself. Background Technology

[0002] As a power unit that uses hydrogen to generate electricity, the stability and reliability of the fuel cell's encapsulation structure are crucial to its lifespan and safety. Screw-mounted fuel cell stacks (hereinafter referred to as screw stacks), a commonly used encapsulation structure, offer advantages such as simple structure, convenient encapsulation, and ease of maintenance and repair. However, due to the characteristics of screw-mounted encapsulation, it also suffers from low reliability of threaded connections, susceptibility to loosening, easy failure of encapsulation pressure, and weak ability to withstand complex operating conditions such as vibration and impact.

[0003] Existing screw stack packaging structures such as Figure 1 and Figure 2 As shown, the main components of the screw stack, namely the cathode end plate 1, cathode insulating plate 2, current collector plate 3, stack core 4, current collector plate 5, anode insulating plate 6, disc spring bearing plate 7, disc spring assembly 8, and anode end plate 9, are stacked in sequence. Then, the cathode end plate 1 and anode end plate 9 are fastened together by multiple sets of screws 10 and nuts 11 to achieve the encapsulation of the fuel cell stack core.

[0004] The sealing force between the negative end plate 1 and the positive end plate 2 of the screw stack is achieved by converting the preload force of the screw 10 and nut 11 into clamping force. The structural characteristics have the following defects, which can easily cause the sealing pressure to fail.

[0005] like Figure 3 As shown, during the screw stacking process, the screw 10 first connects to the threaded hole of the cathode end plate 1, forming a threaded pair ①. At this time, the screw 10 does not bear the clamping force load of the sealing, and the threaded pair ① is in a free axial rotation state without any applied torque.

[0006] During screw stack encapsulation, screw 10 and nut 11 form threaded pair ②. A torque is applied to threaded pair ② to generate a preload, which is then converted into the clamping force between the cathode end plate 1 and the anode end plate 2 to encapsulate the screw stack core and its components. Therefore, the preload is achieved jointly by threaded pair ① and threaded pair ②, and the reliability of the encapsulation clamping force depends entirely on threaded pair ① and threaded pair ②. Loosening of the threaded pair, leading to a reduction in the preload, i.e., the encapsulation clamping force, is a major risk factor for structural failure.

[0007] Based on the structural characteristics of threaded pairs, their ability to prevent loosening depends on the frictional resistance of the contact surface, which poses a significant risk of failure under complex working conditions such as vibration and impact.

[0008] In summary, existing screw stack packaging technologies rely on the frictional force of the threaded connection to maintain preload. However, the threaded pair between the screw and the cathode end plate is unrestrained after assembly, and the threaded pair between the nut and the screw also lacks a continuous and effective anti-loosening mechanism. Under dynamic loads such as vibration, impact, or temperature cycling, both of these threaded pairs are prone to progressive loosening, leading to pressure decay or even failure of the fuel cell stack packaging. Although one-time anti-loosening methods such as applying adhesive or punching can be used, these methods compromise the removability of the threaded pair, making subsequent maintenance, repair, or core replacement difficult, thus deviating from the original design intention of screw stack packaging for easy maintenance. Summary of the Invention

[0009] The purpose of this invention is to provide a screw anti-loosening structure for a fuel cell and a fuel cell, which can effectively improve the stability and reliability of the screw packaging structure and increase the service life and durability of the fuel cell stack.

[0010] The technical solution of this invention is: A screw anti-loosening structure for fuel cell screw stack packaging, the screw stack including a cathode end plate and an anode end plate, and a fastening connection between the cathode end plate and the anode end plate is achieved by a combination of at least one set of screws and tightening nuts, the anti-loosening structure comprising: A rotation limiting unit is used to limit the axial rotation of the screw relative to the male end plate. The rotation limiting unit includes: a first keyway formed on the male end plate, a second keyway formed on the screw, and a square key embedded in both keyways. An anti-loosening torque unit is used to apply a continuous anti-loosening torque to the tightening nut. The anti-loosening torque unit includes: a torsion spring fixed to the male end plate, a torsion ring rotatably sleeved on the tightening nut, and a spline sleeved on the tightening nut and locked to the torsion ring and the tightening nut. One end of the torsion spring is connected to the male end plate, and the other end is connected to the torsion ring. By rotating the torsion ring, the torsion spring can be deformed, and then, through the locking of the spline, the deformation torque of the torsion spring is converted into the anti-loosening torque acting on the tightening nut.

[0011] Furthermore, the outer circumferential surface of the tightening nut is provided axially with a first outer cylindrical surface for rotating and guiding the torsion ring, and a square cylindrical surface for circumferential locking with the spline.

[0012] Furthermore, the inner hole of the torsion ring is provided with a first inner cylindrical surface that mates with the first outer cylindrical surface of the tightening nut; the inner hole of the spline is provided with an inner square groove that mates with the square cylindrical surface of the tightening nut.

[0013] Furthermore, the torsion ring and the spline are circumferentially locked through a spline engagement structure, which includes a spline groove on the torsion ring and spline teeth on the spline.

[0014] Furthermore, the tightening nut is provided with a limiting groove and a shoulder, and is equipped with an elastic retaining ring. The elastic retaining ring is installed in the limiting groove and together with the shoulder, it axially limits the torsion spring, the torsion ring and the spline sleeved on the tightening nut.

[0015] Furthermore, the second keyway has a set length along the axial direction of the screw, so that the square key can adjust its relative axial position with respect to the screw within this length range to accommodate different packaging spacings between the cathode end plate and the anode end plate.

[0016] Furthermore, the male end plate is provided with a first limiting hole for fixing one end of the torsion spring, and the torsion ring is provided with a second limiting hole for fixing the other end of the torsion spring. The working torque range of the torsion spring is adapted to the tightening torque of the tightening nut.

[0017] A fuel cell includes the screw anti-loosening structure described above.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention, through a rotation limiting unit and an anti-loosening torque unit, systematically improves the packaging reliability of the fuel cell stack while maintaining the original detachability advantage of the screw packaging. Specifically, the square key in the rotation limiting unit is embedded in both the anode end plate and the second keyway, directly forming a mechanical lock. This effectively eliminates the rotational freedom of the screw relative to the end plate, thus suppressing the risk of loosening of the threaded pair between the screw and the cathode end plate from the structural root. Simultaneously, the torsion spring in the anti-loosening torque unit generates and stores elastic potential energy during installation. Its continuous output torque is transmitted through a connected torsion ring and maintained by the locking structure between the spline and the tightening nut. Ultimately, it is transformed into a holding torque that always acts on the tightening nut, in the same direction as tightening but opposite to the anti-loosening tendency, actively and persistently resisting the reverse rotation of the threaded pair between the nut and the screw under dynamic conditions such as vibration. Through the synergistic effect between the rotation limit unit and the anti-loosening torque unit, reliable protection is provided for two key weak points in the threaded connection of the screw package. This not only significantly enhances the long-term operational stability and durability of the fuel cell stack in complex environments, but also makes the entire anti-loosening structure fully detachable and reusable. This allows the solution to achieve reliable anti-loosening while still fully inheriting the engineering convenience of traditional screw package structures in terms of easy assembly, disassembly and maintenance. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of an existing fuel cell screw packaging structure.

[0020] Figure 2 This is an exploded view of an existing screw stack.

[0021] Figure 3 This is a schematic diagram of an existing screw connection structure.

[0022] Figure 4 This is a perspective view of the structural schematic diagram of the present invention.

[0023] Figure 5 This is an exploded view of the screw stack of the present invention.

[0024] Figure 6 This is a schematic diagram of the cathode end plate structure of the present invention.

[0025] Figure 7 This is a schematic diagram of the anode end plate structure of the present invention.

[0026] Figure 8 for Figure 7 An enlarged view of the structural diagram of a local area in the middle.

[0027] Figure 9 This is a schematic diagram of the square key structure of the present invention.

[0028] Figure 10 This is a schematic diagram of the screw structure of the present invention.

[0029] Figure 11 for Figure 10 An enlarged view of the structural diagram of a local area in the middle.

[0030] Figure 12 This is a structural schematic diagram from the first perspective of tightening the nut according to the present invention.

[0031] Figure 13 This is a structural schematic diagram from a second perspective of the present invention for tightening the nut.

[0032] Figure 14 This is a schematic diagram of the tightening nut assembly structure of the present invention.

[0033] Figure 15 A schematic diagram of the torsion spring structure of this invention.

[0034] Figure 16 This is a schematic diagram of the torsion ring of the present invention from a first perspective.

[0035] Figure 17 This is a schematic diagram of the torsion ring of the present invention from a second perspective.

[0036] Figure 18 This is a structural schematic diagram of the spline of the present invention from a first perspective.

[0037] Figure 19 This is a structural schematic diagram of the spline of the present invention from a second perspective.

[0038] Figure 20 This is a schematic diagram of the elastic retaining ring structure of the present invention.

[0039] Figure 21 This is a schematic diagram of the screw assembly connection relationship (S0 end plate spacing) of the present invention.

[0040] Figure 22 The screw assembly connection relationship of the present invention (S) Min Schematic diagram of the end plate spacing structure.

[0041] Figure 23 The screw assembly connection relationship of the present invention (S) Max Schematic diagram of the end plate spacing structure.

[0042] Figure 24 This is a schematic diagram of the screw assembly installation of the present invention.

[0043] Figure 25 for Figure 24 An enlarged view of a partial structural diagram.

[0044] Figure 26 This is a schematic diagram of the screw installation of the present invention.

[0045] Figure 27 This is a schematic diagram of the installation of the square key of the present invention.

[0046] Figure 28 This is a schematic diagram of the installation of the tightening nut according to the present invention.

[0047] Figure 29 This is a schematic diagram of the tightening of the nut to a constant torque according to the present invention.

[0048] Figure 30 This is a schematic diagram of the installation of the torsion spring of the present invention.

[0049] Figure 31 This is an initial schematic diagram of the torsion ring of the present invention.

[0050] Figure 32 This is a schematic diagram showing the design position of the torsion ring in this invention.

[0051] Figure 33 This is a schematic diagram of the spline installation of the present invention.

[0052] Wherein, 1-11 are descriptions of components in the prior art: 1. Cathode end plate, 2. Cathode insulating plate, 3. Current collector plate, 4. Core, 5. Current collector plate, 6. Anode insulating plate, 7. Disc spring bearing plate, 8. Disc spring assembly, 9. Anode end plate, 10. Screw, 11. Nut.

[0053] The following is a description of the components related to the screw anti-loosening structure: 12. Cathode end plate; 13. Cathode insulating plate; 14. First current collector plate; 15. Core; 16. Second current collector plate; 17. Anode insulating plate; 18. Disc spring bearing plate; 19. Disc spring assembly; 20. Anode end plate; 21. Square key; 22. Screw; 23. Tightening nut; 24. Torsion spring; 25. Torsion ring; 26. Spline; 27. Elastic retaining ring; 121. Threaded hole; 201. Through hole; 202. Countersunk surface; 203. First keyway; 204. First limiting hole; 221. First external thread; 222. Second external thread; 2 23. Second keyway; 224. Hexagonal boss; 231. Flange face; 232. Internal thread; 233. Guide surface; 234. Tightening surface; 235. First outer cylindrical surface; 236. Square cylindrical surface; 237. Second outer cylindrical surface; 238. Limiting groove; 241. First end torsion arm; 242. Tail end torsion arm; 251. First inner cylindrical surface; 252. Tightening surface; 253. Second limiting hole; 254. Spline groove; 261. Spline teeth; 262. Square groove; 263. Second inner cylindrical surface; 28. Tightening tool; 29. ​​Torque tightening tool. Detailed Implementation

[0054] The following is combined with Figures 1 to 32 The specific embodiments of the present invention will be described in detail below. In the description of the present invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and are not intended to 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 the present invention.

[0055] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0056] It should be noted that the circuit connections involved in this invention all adopt conventional circuit connection methods and do not involve any innovation.

[0057] Example A screw anti-loosening structure for fuel cell is used for fuel cell screw stack encapsulation. The screw stack includes a cathode end plate 12 and an anode end plate 20, and a fast connection between the cathode end plate 12 and the anode end plate 20 is achieved by a combination of at least one set of screws 22 and tightening nuts 23.

[0058] like Figure 5 As shown, the screw stack consists of a cathode end plate 12, a cathode insulating plate 13, a first current collector 14, a stack core 15, a second current collector 16, an anode insulating plate 17, a disc spring bearing plate 18, a disc spring assembly 19, and an anode end plate 20 stacked sequentially. Then, the cathode end plate 12 and the anode end plate 20 are connected by multiple sets of screws 22, tightening nuts 23, and an anti-loosening combination consisting of a square key 21, a torsion spring 24, a torsion ring 25, a spline 26, and an elastic retaining ring 27 to achieve the encapsulation of the fuel cell stack core.

[0059] A screw anti-loosening structure for a fuel cell includes: A rotation limiting unit is used to limit the axial rotation of the screw 22 relative to the male end plate 20. The rotation limiting unit includes: a first keyway 203 formed on the male end plate 20, a second keyway 223 formed on the screw 22, and a square key 21 embedded in both keyways. like Figure 7 and Figure 8 As shown, the cathode end plate 12 has four sets of eight threaded holes 121 symmetrically arranged on its upper and lower sides for matching the first external thread 221 of the screw 22. The threaded holes 121 and the first external thread 221 together form a threaded pair ③. The threaded pair ③ enables the transmission of the clamping force of the screw 22 to the cathode end plate 12.

[0060] like Figure 7 As shown, the anode plate 20 has 4 sets of 8 through holes 201 symmetrically arranged on its upper and lower sides for matching the screw 22. Each through hole 201 has a recessed surface 202 on its outer side that matches the flange face 231 of the tightening nut 23. The clamping force is transmitted to the anode plate 20 through the recessed surface 202 by the combination of the screw 22 and the tightening nut 23. Each through hole 201 has a first keyway 203 on its side that matches the square key 21. Each through hole 201 has a first limiting hole 204 near the inner side of the anode plate 20, which matches the first end torsion arm 241 of the torsion spring 24, thus fixing the first end torsion arm 241 to the anode plate 20.

[0061] like Figure 9 As shown, the square key 21 is a square metal block that is embedded in the first keyway 203 of the male end plate 20 and the second keyway 223 of the screw 22, so that the axial rotational freedom of the screw 22 in the through hole 201 of the male end plate 20 is locked. Even if the rotation of the threaded pair ③ formed by the first external thread 221 of the screw 22 and the threaded hole 121 of the female end plate 12 is restricted, the loosening is suppressed.

[0062] like Figure 10 and Figure 11 As shown, the front end of the screw 22 has a first external thread 221, which matches the threaded hole 121 of the female end plate 12 to form a threaded pair ③, used to transmit the clamping force of the screw 22 to the female end plate 12. The rear end has a second external thread 222, which matches the internal thread 232 of the tightening nut 23 to form a threaded pair ④. The clamping force of the screw 22 is transmitted to the male end plate 20 through the threaded pair ④ and the tightening nut 23. The threaded pair ④ is a right-hand thread. This patent uses a right-hand thread for technical solution description, but the threaded pair specifications can also be adjusted according to specific design. A second keyway 223 is opened in the area of ​​the second external thread 222 at the rear end to match the square key 21. The top of the rear end has a hexagonal boss 224 to match the tightening tool, which matches the sleeve tool to realize the connection of the threaded pair ③ between the screw 22 and the female end plate 12.

[0063] The anti-loosening torque unit is used to apply a continuous anti-loosening torque to the tightening nut 23. The anti-loosening torque unit includes: a torsion spring 24 fixed to the male end plate 20, a torsion ring 25 rotatably sleeved on the tightening nut 23, and a spline 26 sleeved on the tightening nut 23 and locked to the torsion ring 25 and the tightening nut 23; one end of the torsion spring 24 is connected to the male end plate 20, and the other end is connected to the torsion ring 25; by rotating the torsion ring 25, the torsion spring 24 can be deformed, and then through the locking of the spline 26, the deformation torque of the torsion spring 24 is converted into an anti-loosening torque acting on the tightening nut 23.

[0064] like Figure 12 , Figure 13 and Figure 14As shown, the tightening nut 23 is a multi-segment shaft structure with a flange boss and a through threaded hole in the middle, consisting of a flange face 231, a guide face 233, a tightening face 234, a first outer cylindrical face 235, a square cylindrical face 236, a second outer cylindrical face 237, and a limiting groove 238. The internal thread 232 mates with the second external thread 222 of the screw 22, forming a threaded pair ④. The flange face 231 matches the countersunk surface 202 of the male end plate 20, transmitting the clamping force of the tightening nut 23 and the screw 22 to the male end plate 20. The guide face 233 matches the torsion spring 24, realizing the axial guiding function of the torsion spring 24 during the torsion process. The tightening face 234 serves as a tightening structure for matching tightening tools, such as a torque wrench, to achieve torque tightening of the tightening nut 23. The first outer cylindrical face 235 matches the first inner cylindrical face 251 of the torsion ring 25, providing positioning and guiding functions during the axial rotation of the torsion ring 25. The square cylindrical surface 236 matches the square groove 262 of the spline 26, locking the nut 23 and spline 26 in axial rotational freedom. The second outer cylindrical surface 237 matches the second inner cylindrical surface 263 of the spline 26, serving as a guide during spline 26 installation. The limiting groove 238 matches the elastic retaining ring 27, and together with the shoulders between the guide surface 233, the first outer cylindrical surface 235, the square cylindrical surface 236, and the second outer cylindrical surface 237, limits and locks the torsion spring 24, torsion ring 25, and spline 26 installed on the nut 23 in axial direction.

[0065] The specifications and technical requirements for torsion spring 24 refer to [GB / T 1239.3-2009], such as... Figure 15 As shown, the rotation direction is right-handed, and the selected working torque range is adapted to the tightening torque T0 of the tightening nut 23. The torsion spring 24 has a torsion arm 241 at its first end, which matches and is fixed to the first limiting hole 204 of the male end plate 20. The torsion spring 24 has a torsion arm 242 at its tail end, which matches and is fixed to the second limiting hole 253 of the torsion ring 25. By rotating the torsion ring 25 counterclockwise along the axial direction, the torsion spring 24 can be twisted to the designed position to generate a clockwise working torque T. N0 .

[0066] like Figure 16 and Figure 17As shown, the torsion ring 25 is a ring-shaped structure with a support arm. The center of the torsion ring 25 has a first inner cylindrical surface 251, which matches the first outer cylindrical surface 235 of the tightening nut 23, serving a positioning and guiding function during the axial rotation of the torsion ring 25. The outer side of the torsion ring 25 has an approximately hexagonal tightening surface 252, used to match a torsion tool to achieve counterclockwise torsion of the torsion ring 25 along the axial direction. The support arm of the torsion ring 25 has a through second limiting hole 253, which matches the tail torsion arm 242 of the torsion spring 24. When the torsion ring 25 rotates counterclockwise along the axial direction, the second limiting hole 253 drives the tail torsion arm 242 of the torsion spring 24, causing the tail torsion arm 242 of the torsion spring 24 to rotate to the designed position. At this time, the torsion spring 24 generates a clockwise working torque T. N0 The torsion ring 25 has a spline groove 254 on one side, which matches the spline teeth 261 of the spline 26, thereby locking the rotational freedom of the torsion ring 26 and the spline 26 along the axial direction. The support arm of the torsion ring 25 has a through second limiting hole 253.

[0067] like Figure 18 and Figure 19 As shown, spline 26 is a centrally continuous ring structure. One side of spline 26 has a spline tooth 261 that matches the spline groove 254 of the torsion ring 25, locking the axial rotational freedom of the torsion ring 25 and spline 26. On the same side of the spline tooth 261, spline 26 has an inner square groove 262 that matches the square cylindrical surface 236 of the tightening nut 23, locking the axial rotational freedom of the spline 26 and the tightening nut 23. The engagement of the spline tooth 261 and spline groove 254, and the engagement of the square groove 262 and square cylindrical surface 236, together lock the axial rotational freedom of the tightening nut 23, spline 26, and torsion ring 25.

[0068] like Figure 20 As shown, the specifications and technical requirements of the elastic retaining ring 27 refer to [GB / T 894-2017], and it is adapted to the limiting groove 238 of the tightening nut 23.

[0069] The screw anti-loosening structure of a fuel cell in this embodiment effectively suppresses the problem of loosening of the threaded connection ③ between the screw 22 and the cathode end plate 12, improving the reliability of the connection. By cooperating with the square key 21, the first keyway 203 of the anode end plate 20, and the second keyway 223 of the screw 22, the axial rotational freedom of the screw 22 is locked, thereby locking the threaded connection ③ between the screw 22 and the cathode end plate 12, effectively suppressing the loosening failure problem.

[0070] Considering the structural characteristics of fuel cells, the core length may fluctuate around the design value. This embodiment presents a screw anti-loosening structure for a fuel cell that effectively addresses changes in assembly position caused by variations in the fuel cell core length, demonstrating good adaptability. Figure 21 , Figure 22 and Figure 23 As shown, when adapting to different core lengths, the spacing between the cathode end plate 12 and the anode end plate 20 is S. Max Maximum value, S0 design value and S Min When the minimum value changes, the square key 21 is adapted to different positions P by utilizing the length redundancy of the second keyway 223 of the screw 22. Max P0 and P Min This enables the screw assembly anti-loosening structure to be compatible with different core lengths.

[0071] like Figure 14 , Figure 21 , Figure 22 and Figure 23 As shown, screw 22, square key 21, and male end plate 20 are defined as combination ⑤ to lock the axial rotational degree of freedom. Tightening nut 23, torsion ring 25, and spline 26 are defined as combination ⑥ to lock the axial rotational degree of freedom. The first end torsion arm 241 of the torsion spring 24 is matched and fixed to the first limiting hole 204 of the male end plate 20. The last end torsion arm 242 is matched and fixed to the second limiting hole 253 of the torsion ring 25. When the torsion spring 24 is twisted counterclockwise around the axis to the designed position, it generates a clockwise working torque T. N0 This is converted into the torque T between combination ⑤ and combination ⑥. N0 That is, the torque T of the screw 22 in combination ⑤ and the tightening nut 23 in combination ⑥. N0 This torque T N0 The tightening direction of threaded pair ④ is the same as that of threaded pair ④, while the loosening direction is opposite to that of threaded pair ④. That is, the loosening of threaded pair ④ is subject to a torque T. N0 Due to its effect, the loosening of threaded pair ④ is continuously suppressed.

[0072] Following the encapsulation process of the fuel cell screw stack, after the pre-compression of the cathode end plate 12 and anode end plate 20 is completed, the screw 22 is installed and the nut 23 is tightened. The installation of a specific screw 22 in the screw stack is described in detail below. Figure 24 and Figure 25 As shown. All other screws 22 in the screw stack are manufactured using this scheme. Once all screws 22 are completed, they will appear as shown. Figure 4 As shown.

[0073] like Figure 26 As shown, after the screw stacking pre-compression is completed, i.e., when the gap between the cathode end plate 12 and the anode end plate 20 reaches the designed spacing S0, the screw 22 is installed into the threaded hole 121 of the cathode end plate 12, so that the connection length of the threaded pair ③ reaches the designed value L3. At this time, due to the randomness of the position of the helix of each threaded pair on the part, the second keyway 223 of the anode end plate 20 may not be aligned with the first keyway 203 of the screw 22. Figure 27As shown, continue screwing in the screw 22 until the second keyway 223 aligns with the first keyway 203, and then move the square key 21 from... Figure 27 Slide into position P as shown. Figure 28 At position P0, tighten the nut 23 into the screw 22. At this time, the square key 21 is confined within the space formed by the first keyway 203, the keyway 22 and the tightening nut 23, and the axial rotational freedom of the screw 22 is locked, thus suppressing the loosening of the threaded pair ③.

[0074] After tightening nut 23 into screw 22, use tightening tool 28 to match the tightening face 234 of tightening nut 23 to achieve a constant torque T0 tightening, such as... Figure 29 As shown. Then, the torsion spring 24 is installed into the guide surface 233 of the tightening nut 23, and the first end torsion arm 241 is fixed in the limiting hole 203 of the male end plate 20. At the same time, the torsion ring 25 is installed into the tightening nut, with its first inner cylindrical surface 251 matching the first outer cylindrical surface 235 of the tightening nut 23. The tail end torsion arm 242 of the torsion spring 24 is fixed in the limiting hole 253 of the torsion ring 25, as shown. Figure 30 As shown. Figure 31 As shown, the torsion arm 242 at the tail end of the torsion spring 24 and the torsion ring 25 are in a free state at position N. A torque-controlled tightening tool 29 is used to match the tightening surface 252 of the torsion ring 25 to achieve a torque T. N0 T N0 =T0, at this time the torsion spring 24 deforms, and the tail-end torsion arm 242 rotates to the designed position N0, such as Figure 32 As shown.

[0075] When the torsion ring 25 is twisted to the design position N0, as follows Figure 33 As shown, the spline 26 is installed into the tightening nut 23. The square groove 262 of the spline 26 matches the square cylindrical surface 236 of the tightening nut 23. At the same time, the torsion ring 25 is rotated appropriately. After adjusting the limited rotation angle, the multiple teeth of the spline 26 are fully engaged. The actual torque T of the torsion spring 24 after adjustment is then determined. NA ≈T N0 =T0, deviation ±10%, negligible and can be considered as T NA =T0, after aligning the spline teeth 261 of spline 26 with the spline groove 254 of the torsion ring, axially press spline 26 into the designed position to achieve spline engagement, and install the elastic retaining ring 27 to complete the assembly, as shown. Figure 14 The design status.

[0076] like Figure 14 As shown, assembly ⑤ consists of screw 22, square key 21, and male end plate 20 locking the axial rotational degree of freedom; assembly ⑥ consists of tightening nut 23, torsion ring 25, and spline 26 locking the axial rotational degree of freedom. The torsion spring 24, at its designed position, generates a clockwise working torque T around the axial direction through deformation.NA The transformation between combination ⑤ and combination ⑥ generates an axial clockwise torque T. NA That is, the screw 22 in combination ⑤ and the tightening nut 23 in combination ⑥ continuously have a clockwise torque T. NA T NA =T0, and the directions are the same. Therefore, it can be concluded that the threaded pair ④ continuously has a torque generated by the deformation of the torsion spring 24, which is in the same direction as the tightening of the threaded pair ④ but opposite to the unloosening direction, and the unloosening of the threaded pair ④ is continuously suppressed.

[0077] In summary, this embodiment effectively reduces the risk of loosening in the screw stack threaded connection structure by combining the rotation limit unit and the anti-loosening torque unit, thereby improving the reliability and stability of the screw stack packaging structure.

[0078] A fuel cell includes the aforementioned screw anti-loosening structure.

[0079] The above-disclosed embodiments are merely preferred embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A screw anti-loosening structure for a fuel cell, used for fuel cell screw stack encapsulation, the screw stack comprising a cathode end plate and an anode end plate, and wherein a fastening connection between the cathode end plate and the anode end plate is achieved by a combination of at least one set of screws and tightening nuts, characterized in that, The anti-loosening structure includes: A rotation limiting unit is used to limit the axial rotation of the screw relative to the male end plate. The rotation limiting unit includes: a first keyway formed on the male end plate, a second keyway formed on the screw, and a square key embedded in both keyways. An anti-loosening torque unit is used to apply a continuous anti-loosening torque to the tightening nut. The anti-loosening torque unit includes: a torsion spring fixed to the male end plate, a torsion ring rotatably sleeved on the tightening nut, and a spline sleeved on the tightening nut and locked to the torsion ring and the tightening nut. One end of the torsion spring is connected to the male end plate, and the other end is connected to the torsion ring. By rotating the torsion ring, the torsion spring is deformed, and then the deformation torque of the torsion spring is converted into the anti-loosening torque acting on the tightening nut through the locking of the spline.

2. The screw anti-loosening structure for a fuel cell according to claim 1, characterized in that, The outer circumferential surface of the tightening nut is provided with a first outer cylindrical surface for rotating and guiding the torsion ring, and a square cylindrical surface for circumferential locking with the spline.

3. The screw anti-loosening structure for a fuel cell according to claim 2, characterized in that, The inner hole of the torsion ring is provided with a first inner cylindrical surface that mates with the first outer cylindrical surface of the tightening nut; the inner hole of the spline is provided with an inner square groove that mates with the square cylindrical surface of the tightening nut.

4. The screw anti-loosening structure for a fuel cell according to claim 3, characterized in that, The torsion ring and the spline are circumferentially locked through a spline engagement structure, which includes a spline groove on the torsion ring and spline teeth on the spline.

5. The screw anti-loosening structure for a fuel cell according to claim 1, characterized in that, The tightening nut is provided with a limiting groove and a shoulder, and is equipped with an elastic retaining ring. The elastic retaining ring is installed in the limiting groove and together with the shoulder, it axially limits the torsion spring, the torsion ring and the spline sleeved on the tightening nut.

6. The screw anti-loosening structure for a fuel cell according to claim 1, characterized in that, The second keyway has a set length along the axial direction of the screw, so that the square key can adjust its relative axial position with respect to the screw within this length range.

7. The screw anti-loosening structure for a fuel cell according to claim 1, characterized in that, The male end plate is provided with a first limiting hole for fixing one end of the torsion spring, and the torsion ring is provided with a second limiting hole for fixing the other end of the torsion spring. The working torque range of the torsion spring is adapted to the tightening torque of the tightening nut.

8. A fuel cell, characterized in that, The screw anti-loosening structure includes any one of claims 1 to 8.

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