Low-temperature-resistant explosion-proof power distribution device

Abstract

The invention discloses a low-temperature-resistant explosion-proof power distribution device which comprises an explosion-proof power distribution box body, a box body opening is formed in the front side of the explosion-proof power distribution box body, the explosion-proof power distribution box body is hinged to a box cover door through a hinge arm on the side portion, and the box cover door rotates around the hinge position through the hinge arm so that the box cover door can be tightly attached to the box body opening to be closed or separated from the box body opening to be opened. The box cover door and the box body opening are fixed through a fastening screw assembly when being closed; a positioning ring piece is tightly sleeved on the outer wall of the box cover door, can slide outside the box cover door along the thickness direction of the box cover door through an adjusting mechanism, and is sleeved at the joint of the box cover door and the box body opening through sliding; according to the explosion-proof power distribution device, the box cover door can be opened conveniently, meanwhile, the sealing effect of the joint of the box cover door and the box opening can be improved, stable positioning after the box cover door is closed is achieved, and the safety sealing performance is improved; the sealing ring and the fastening screw assembly can be stably positioned in the low-temperature environment, and the safety sealing performance in the low-temperature environment is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of electrical equipment, and in particular relates to a low-temperature resistant explosion-proof power distribution device. Background Art

[0002] ‌Explosion-proof distribution box is an electrical equipment suitable for explosive environment. Electrical equipment with explosion-proof enclosure is called "explosion-proof electrical equipment". The live parts of the electrical equipment are placed in a special enclosure. The enclosure has the function of isolating the sparks and arcs generated by the electrical parts inside the enclosure from the explosive mixture outside the enclosure, and can withstand the explosion pressure generated when the explosive mixture entering the enclosure is ignited by the sparks and arcs of the electrical equipment inside the enclosure without being damaged; it can prevent the explosion products inside the enclosure from spreading to the explosive mixture outside the enclosure, and will not cause the explosive mixture outside the enclosure to burn or explode.

[0003] Therefore, the sealing of the explosion-proof distribution box is very important, especially at the box cover door that needs to be opened and closed. In order to improve the sealing and stability of the box cover door, at present, the box body and the box cover are connected with bolts, and there is a protruding boss on the inner end surface of the box cover. When the distribution box is closed, the boss is inserted into the box body to improve stability and sealing. This explosion-proof distribution box is extremely inconvenient to operate.

[0004] In order to solve the inconvenience problem during operation, publication number CN111463679B discloses an explosion-proof distribution box, which can slide back and forth in the second hinge hole along the hole direction by setting a hinge shaft, and pull the box cover to move away from the box body. After the box cover is rotated open, it is hung on the box body. There is no need to store the box cover separately, saving time and effort. However, for the above-mentioned explosion-proof distribution box, since the hinge shaft can slide back and forth, the limit of the box cover in the forward opening direction is mainly dependent on external screws, and the positioning effect is poor, which affects the sealing of the sealing surface of the box cover; although a sealing ring is provided inside the box cover, when the explosion-proof distribution device is used in cold areas, the low temperature environment will have an impact on the sealing ring and screws, causing the sealing ring and screws to shrink, thereby affecting the sealing, and there is a safety hazard in an explosive environment. Summary of the invention

[0005] The present invention provides a low-temperature resistant explosion-proof power distribution device, which can realize the convenient opening of the box cover door, and at the same time can improve the sealing effect of the connection between the box cover door and the box body opening, realize the stable positioning of the box cover door after closing, and improve the safety sealing; in a low-temperature environment, the sealing ring and the fastening screw assembly can achieve stable positioning, further improving the safety sealing in a low-temperature environment, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a low-temperature resistant explosion-proof power distribution device, comprising an explosion-proof power distribution box, a box opening is provided on the front side of the explosion-proof power distribution box, the explosion-proof power distribution box is hinged with a box cover door through a hinged arm on the side, the box cover door is rotated around the hinge by the hinge arm to achieve close contact with the box opening or separate opening, the box cover door and the box opening are provided with close sealing surfaces to achieve sealing after close contact; when the box cover door and the box opening are closed, they are fixed by a fastening screw assembly, and the fastening screw assembly is fixed at the box cover door and the edge of the box opening; the box cover door is tightly sleeved with a positioning ring along a circle of the outer wall, and the positioning ring can slide along its thickness direction outside the box cover door through an adjustment mechanism, the box opening protrudes from the surface of the explosion-proof power distribution box, and the positioning ring is sleeved on the connection between the box cover door and the box opening, or leaves the connection between the box cover door and the box opening by sliding.

[0007] Preferably, a sealing ring is provided at the sealing surface between the box cover door and the box body opening, and the box body opening and the box cover door are provided with grooves corresponding to the sealing ring, and the grooves on both sides together enclose a sealing ring groove, and the cross-section of the sealing ring groove is gourd-string-shaped, and the gourd-string-shaped sealing ring grooves are vertically arranged, and at least three strings are arranged, and the diameter of each string is consistent, and the cross-section of the sealing ring is a gourd-string structure that is compatible with the sealing ring groove.

[0008] Preferably, the sealing ring groove on the box cover door and the box body opening is asymmetrically designed, and the sizes of the sealing ring groove on the box cover door and the box body opening are different.

[0009] Preferably, two sealing rings are provided, the cross-sectional dimensions of the two sealing rings are the same, but the diameters of the two sealing rings around the center of the circle are different, a gap is provided between the two sealing rings, the parts of the two sealing rings located inside the box cover door are different in size, and the parts located inside the box body opening are also different in size.

[0010] Preferably, the adjustment mechanism includes a lug installed on the outer edge of the box cover door, and the lug is provided in plurality, and the plurality of lugs are equally divided around the center of the box cover door, the lug is provided with a through hole, a positioning rod corresponding to the lug is welded on the positioning ring, the positioning rod passes through the lug through hole, and the positioning rod is sleeved with a pressure spring located between the lug and the positioning ring.

[0011] Preferably, a baffle located on a different side of the lug relative to the positioning ring is welded to the end of the positioning rod.

[0012] Preferably, the fastening screw assembly includes a screw, the screw head end is provided with a small diameter end with a smaller diameter, the small diameter end is provided with a thread, and the thread on the outer wall of the small diameter end is opposite to the thread direction of the screw, the screw and the small diameter end are respectively threaded with a first nut and a second nut, and the screw sleeve is provided with a hard spring located between the first nut and the second nut.

[0013] Preferably, the box body opening is further provided with an outwardly extending edge after protruding out of the explosion-proof distribution box body, the fastening screw assembly fixes the box cover door to the edge, and the first nut is tightly attached to the side of the edge.

[0014] Preferably, a positioning mechanism for positioning the hard spring is provided on the first nut and the second nut.

[0015] Preferably, the positioning mechanism includes a first socket and a second socket on the first nut and the second nut respectively, and a first plug and a second plug extending parallel to the axial direction of the spiral are provided at both ends of the hard spring. The first plug and the second plug are respectively inserted into the first socket and the second socket and tightly fit with their inner walls.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. By putting an adjustable positioning ring on the connection between the box cover door and the box body opening, not only can the sealing effect of the connection between the box cover door and the box body opening be improved, but also the front and rear direction positioning can be achieved in conjunction with the fastening screw assembly. Since the box cover door can only rotate around the hinged arm, interference is formed, so that the box cover door can be stably positioned after closing, thereby improving safety and sealing.

[0017] 2. By setting the sealing ring groove and the sealing ring into a gourd string shape, after the sealing ring shrinks, the upper string and the lower string will produce a shrinkage displacement toward the center of the middle string. After shrinkage, the outer walls of the upper and lower strings will still be elastically squeezed at the upper and lower clamping grooves to form a seal, thereby improving the sealing performance in a low-temperature environment.

[0018] 3. The first nut and the second nut are positioned by setting a hard spring. When the first nut and the second nut rotate in opposite directions, a torsion force will be generated on the hard spring, and the hard spring will provide reverse resistance, so that the first nut and the second nut keep rotating in the same direction. Since the thread directions are opposite, the first nut and the second nut will move in a mirror image, and the first nut and the second nut are difficult to move in a mirror image, so they are very stable in a low temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the main structure of the box cover door of the present invention after it is opened; Figure 2 It is a schematic diagram of the box cover door closing structure of the present invention; Figure 3 It is a partial cross-sectional structural schematic diagram of the present invention; Figure 4 It is a schematic diagram of the sealing ring and the sealing ring groove structure after shrinkage of the present invention; Figure 5 It is a schematic diagram of the side view structure of the positioning ring and the positioning rod of the present invention; Figure 6 It is a schematic cross-sectional structural diagram of a fastening screw assembly of the present invention; Figure 7 This is a schematic diagram of the first nut structure of the present invention; Figure 8 It is a schematic diagram of the second nut structure of the present invention; Fig. 9 It is a schematic diagram of the hard spring structure of the present invention.

[0020] In the figure: 1. explosion-proof distribution box; 2. box mouth; 3. hinged arm; 4. box cover door; 5. positioning ring; 6. sealing ring; 7. lug; 8. positioning rod; 9. pressure spring; 10. baffle; 11. screw; 12. small diameter end; 13. first nut; 14. second nut; 15. hard spring; 16. edge; 17. first socket; 18. second socket; 19. first plug; 20. second plug. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] See also Figure 1-2The present invention provides a low-temperature resistant explosion-proof power distribution device, comprising an explosion-proof power distribution box 1, wherein the front side of the explosion-proof power distribution box 1 is provided with a box opening 2, and the explosion-proof power distribution box 1 is hinged with a box cover door 4 through a hinged arm 3 at the side, and the box cover door 4 is rotated around the hinge by the hinged arm 3 to achieve close contact with the box opening 2 or separate opening, and the box cover door 4 and the box opening 2 are provided with a close sealing surface to achieve sealing after close contact, and the box cover door 4 is not provided with a boss, so that the box cover door 4 can be conveniently opened, and the box cover door 4 after opening can be opened by the hinged arm 3. The box cover door 4 and the box body opening 2 are fixed by a fastening screw assembly when they are closed. The fastening screw assembly is fixed at the edges of the box cover door 4 and the box body opening 2. The box cover door 4 and the box body opening 2 are fixed by the fastening screw assembly. The box cover door 4 and the box body opening 2 can be fixed in the front and rear directions by the fastening screw assembly, thereby improving stability and increasing safety. The box cover door 4 is tightly fitted with a positioning ring 5 along the outer wall. The positioning ring 5 can slide outside the box cover door 4 along its thickness direction through an adjustment mechanism. The box body opening 2 protrudes from the surface of the explosion-proof distribution box body 1, and the positioning ring 5 is slidably sleeved on the connection between the box cover door 4 and the box body opening 2, or leaves the connection between the box cover door 4 and the box body opening 2, so that the box cover door 4 can be opened or locked by sliding the positioning ring 5 back and forth. When closing the box cover door 4, the positioning ring 5 is pulled backward, and then the box cover door 4 and the box body opening 2 are tightly closed by controlling the handle, and then the positioning ring 5 is released, and the positioning ring 5 is sleeved on the connection between the box cover door 4 and the box body opening 2 by adjusting the mechanism, which can not only improve the box cover door 4 and the box body opening 2, but also improve the box cover door 4 and the box body opening 2. The sealing effect at the connection between the body opening 2 can also cooperate with the fastening screw assembly to achieve front-to-back positioning. Since the box cover door 4 can only rotate around the hinged arm 3, the rotation and opening action of the box cover door 4 around the hinged arm 3 interferes with the positioning ring 5 and the fastening screw assembly to achieve front-to-back positioning, thereby achieving stable positioning of the box cover door 4 after closing and improving safety. When it needs to be opened, remove the fastening screw assembly, then adjust the positioning ring 5 forward to disengage it from the connection between the box cover door 4 and the box body opening 2, and then pull the box cover door 4 around the hinged arm 3 by the handle to rotate and open it.

[0023] See also Figure 3-4A sealing ring 6 is provided at the sealing surface where the box cover door 4 and the box body opening 2 are in close contact. The box body opening 2 and the box cover door 4 are provided with grooves corresponding to the sealing ring 6. The grooves on both sides together enclose a sealing ring groove. The cross section of the sealing ring groove is in the shape of a gourd string. The gourd string-shaped sealing ring grooves are vertically arranged, at least three strings are arranged, and the diameter of each string is consistent. The cross section of the sealing ring 6 is a gourd string structure that is compatible with the sealing ring groove. In this embodiment, by arranging grooves on both sides and then enclosing a sealing ring groove, the sealing ring 6 can be installed in the groove on one side, and then closed with the groove on the other side. The groove is tightly sealed, and the sealing ring 6 is a low-temperature resistant sealing ring to reduce the elastic change and volume change of the sealing ring 6 caused by low temperature. The sealing ring groove and the sealing ring 6 are arranged in a gourd string shape, and at least three strings are arranged. When the sealing ring 6 shrinks more relative to the sealing ring groove at low temperature, after the sealing ring 6 shrinks, the upper string and the lower string will both produce a shrinkage displacement toward the center of the middle string. Since the connection between each string is a clamping groove with a smaller diameter, the outer walls of the upper and lower strings will still be elastically squeezed at the upper and lower clamping grooves after shrinkage to form a seal, thereby improving the sealing performance in a low-temperature environment.

[0024] See also Figure 3-4 The sealing ring groove is asymmetrically designed on the box cover door 4 and the box body opening 2, and the sizes of the sealing ring groove on the box cover door 4 and the box body opening 2 are different; in the present embodiment, the sizes of the sealing ring groove on the box cover door 4 and the box body opening 2 are different, so that the sealing ring 6 can be directly placed in the larger groove, which not only facilitates the positioning and installation of the sealing ring 6 on the box cover door 4 or the box body opening 2, but also improves the stability. At the same time, the gourd-shaped sealing ring groove, when the groove is larger than half, the groove will close inward at the upper and lower edges, which further improves the installation stability of the sealing ring 6 and prevents it from falling during the opening and closing of the box cover door 4.

[0025] See also Figure 3-4 Two sealing rings 6 are provided, and the cross-sectional dimensions of the two sealing rings 6 are the same, but the diameters of the two sealing rings 6 around the center of the circle are different, and a gap is provided between the two sealing rings 6. The sizes of the parts of the two sealing rings 6 located in the box cover door 4 are different, and the sizes of the parts located in the box body opening 2 are also different. In this embodiment, two circles of sealing rings 6 are provided, and there is a gap between the two circles, one circle is sleeved outside the other circle, so as to realize double sealing, and the cross-sectional dimensions of the sealing rings 6 are the same, so as to facilitate the opening of the sealing ring groove.

[0026] See also Figure 1 , Figure 3 , Figure 5The adjusting mechanism comprises a lug 7 mounted on the outer edge of the box cover door 4, wherein a plurality of lugs 7 are provided, and the plurality of lugs 7 are equally arranged around the center of the box cover door 4, and the lug 7 is provided with a through hole, and a positioning rod 8 corresponding to the lug 7 is welded on the positioning ring 5, and the positioning rod 8 passes through the through hole of the lug 7, and a pressure spring 9 located between the lug 7 and the positioning ring 5 is sleeved on the positioning rod 8; in this embodiment, the lug 7 provides a guide support for the positioning rod 8, and the elastic extrusion of the positioning ring 5 is realized by the pressure spring 9, and the positioning ring 5 is pulled backward when the box cover door 4 is closed, Then, the box cover door 4 and the box body opening 2 are tightly closed by controlling the handle, and then the positioning ring 5 is loosened, and the positioning ring 5 is sleeved on the connection between the box cover door 4 and the box body opening 2 by the pressure spring 9. When in use, the positioning ring 5 is sealed at the connection between the box cover door 4 and the box body opening 2 under the extrusion of the pressure spring 9. When the box cover door 4 needs to be opened, the positioning ring 5 is pulled forward by squeezing the pressure spring 9, so that the positioning ring 5 can be detached from the connection between the box cover door 4 and the box body opening 2. The pressure spring 9 is a low-temperature resistant strong spring, so that the positioning ring 5 is not easily compressed by the pressure spring 9 under external factors, thereby avoiding shaking during use.

[0027] See also Figure 3 The end of the positioning rod 8 is welded with a baffle 10 located on a different side of the lug 7 relative to the positioning ring 5; in this embodiment, the baffle 10 can be set to block the positioning rod 8 to prevent it from detaching from the lug 7, thereby affecting the positioning and sealing of the connection between the box cover door 4 and the box body opening 2.

[0028] See also Figure 6The fastening screw assembly includes a screw 11, a small diameter end 12 with a smaller diameter is provided at the head end of the screw 11, a thread is provided on the outside of the small diameter end 12, and the thread of the outer wall of the small diameter end 12 is opposite to the thread direction of the screw 11, and the first nut 13 and the second nut 14 are respectively threaded on the outside of the screw 11 and the small diameter end 12, and the outer sleeve of the screw 11 is provided with a hard spring 15 located between the first nut 13 and the second nut 14; in this embodiment, when the box cover door 4 is fixed to the box body opening 2, the screw 11 is screwed on, and then the first nut 13 is screwed on the screw 11, and the first nut 13 is tightened, and then the hard spring 15 is covered on the part of the screw 11 exposed from the first nut 13, and then the small diameter end 12 is reversely tightened. The second nut 14 is rotated and screwed on, so that the second nut 14 is tightened and squeezed against the hard spring 15. During this period, due to the squeezing of the hard spring 15, the first nut 13 will always be subjected to elastic pressure in the tightening direction. Therefore, when the external temperature is low, the first nut 13 will not loosen after the screw 11 and the first nut 13 shrink. At the same time, since the first nut 13 and the second nut 14 rotate in opposite directions, if the second nut 14 loosens and rotates outward, a rotational force will be given to the first nut 13 through the squeezed hard spring 15. This rotational force will cause the first nut 13 to rotate in the close-fitting direction. Since the first nut 13 is in a tightened state, resistance is given to the hard spring 15 and the second nut 14, so that the second nut 14 is not easy to loosen and rotate outward.

[0029] See also Figure 6 After the box opening 2 protrudes from the explosion-proof distribution box 1, an outwardly extending edge 16 is provided. The fastening screw assembly fixes the box cover door 4 to the edge 16, and the first nut 13 is close to the side of the edge 16. In this embodiment, the box opening 2 protrudes from the explosion-proof distribution box 1 to provide installation space for the screw 11, the first nut 13 and the second nut 14, and the edge 16 is provided to facilitate the close fixation of the first nut 13.

[0030] See also Figure 6 , a positioning mechanism for positioning the hard spring 15 is provided on the first nut 13 and the second nut 14; in this embodiment, the first nut 13 and the second nut 14 can be positioned by setting the positioning mechanism so that they can rotate in the same direction, and because the threads are designed in opposite directions, when the second nut 14 is rotated to loosen, the first nut 13 is prompted to continue to rotate in the same direction and tighten tightly, while the first nut 13 cannot be tightened further, which can form a reverse resistance to the second nut 14, hindering its loosening and enhancing stability; when the first nut 13 is loose, the second nut 14 will continue to rotate in the same direction and tighten, and the hard spring 15 continues to squeeze, thereby forming a reverse resistance to the loosening of the first nut 13, hindering its loosening and enhancing stability.

[0031] See also Figure 6-9The positioning mechanism includes a first plug hole 17 and a second plug hole 18 on the first nut 13 and the second nut 14 respectively. The two ends of the hard spring 15 are provided with a first plug 19 and a second plug 20 extending parallel to the spiral axis direction. The first plug 19 and the second plug 20 are respectively inserted into the first plug hole 17 and the second plug hole 18, and fit closely with their inner walls; in this embodiment, the hard spring 15 selects a low-temperature resistant strong spring to improve its performance at external low temperatures, and the hard structure of the first plug 19 and the second plug 20 is not easy to be pulled and deformed; when installing, first screw on the first nut 13, then put on the hard spring 15, and insert the first plug 19 of the hard spring 15 into the first plug hole 17, and then screw on the second nut Mother 14, when the second nut 14 is tightened to squeeze the hard spring 15 and the second plug 20 is inserted into the second jack 18, the hard spring 15 positions the first nut 13 and the second nut 14 through the plugs at both ends. When the first nut 13 and the second nut 14 rotate in opposite directions, a torsional force will be formed on the hard spring 15, and the hard spring 15 is not easy to twist and will give reverse resistance, so that the first nut 13 and the second nut 14 keep rotating in the same direction. Since the thread directions are opposite, the first nut 13 and the second nut 14 have mirror motion, and the first nut 13 cannot move away when it is in a tightened state, and when the first nut 13 rotates close to the second nut 14, it will be squeezed by the hard spring 15 and cannot rotate, so it is very stable in a low temperature environment.

[0032] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low temperature resistant explosion-proof power distribution device, comprising an explosion-proof power distribution box (1), characterized in that: The explosion-proof power distribution box (1) is provided with a box opening (2) on the front side. The explosion-proof power distribution box (1) is hingedly connected to a box cover door (4) via a hinged arm (3) at the side. The box cover door (4) is rotated around the hinged part by the hinged arm (3) to achieve close contact with the box opening (2) or separate opening. The box cover door (4) and the box opening (2) are provided with close contact sealing surfaces to achieve sealing after close contact. When the box cover door (4) and the box opening (2) are closed, they are fixed by a fastening screw assembly. The fastening screw assembly is The assembly is fixed at the edge of the box cover door (4) and the box body opening (2); the box cover door (4) is tightly fitted with a positioning ring (5) along the outer wall; the positioning ring (5) can slide outside the box cover door (4) along the thickness direction thereof through an adjustment mechanism; the box body opening (2) protrudes from the surface of the explosion-proof distribution box body (1); the positioning ring (5) is slidably sleeved on the connection between the box cover door (4) and the box body opening (2), or leaves the connection between the box cover door (4) and the box body opening (2).

2. A low temperature resistant explosion-proof power distribution device according to claim 1, characterized in that: A sealing ring (6) is provided at the sealing surface where the box cover door (4) and the box body opening (2) are in close contact with each other. The box body opening (2) and the box cover door (4) are provided with grooves corresponding to the sealing ring (6). The grooves on both sides together enclose a sealing ring groove. The cross section of the sealing ring groove is in the shape of a gourd string. The gourd string-shaped sealing ring grooves are arranged vertically, and at least three strings are arranged. The diameter of each string is the same. The cross section of the sealing ring (6) is a gourd string-shaped structure that is compatible with the sealing ring groove.

3. A low temperature resistant explosion-proof power distribution device according to claim 2, characterized in that: The sealing ring groove on the box cover door (4) and the box body opening (2) is designed asymmetrically, and the size of the sealing ring groove on the box cover door (4) and the size of the groove on the box body opening (2) are different.

4. A low temperature resistant explosion-proof power distribution device according to claim 3, characterized in that: Two sealing rings (6) are provided, and the cross-sectional dimensions of the two sealing rings (6) are the same, but the diameters of the two sealing rings (6) around the center of the circle are different, and a gap is provided between the two sealing rings (6). The parts of the two sealing rings (6) located inside the box cover door (4) are different in size, and the parts located inside the box body opening (2) are also different in size.

5. The low temperature resistant explosion-proof power distribution device according to claim 1, characterized in that: The adjustment mechanism comprises a lug (7) mounted on the outer edge of the box cover door (4), wherein a plurality of lugs (7) are provided, and the plurality of lugs (7) are equally distributed around the center of the box cover door (4), and the lug (7) is provided with a through hole, and a positioning rod (8) corresponding to the lug (7) is welded on the positioning ring (5), and the positioning rod (8) passes through the through hole of the lug (7), and a pressure spring (9) is sleeved on the positioning rod (8) and is located between the lug (7) and the positioning ring (5).

6. A low temperature resistant explosion-proof power distribution device according to claim 5, characterized in that: A baffle (10) is welded to the end of the positioning rod (8) and is located on a different side of the lug (7) relative to the positioning ring (5).

7. A low temperature resistant explosion-proof power distribution device according to claim 1, characterized in that: The fastening screw assembly comprises a screw (11), the head end of the screw (11) is provided with a small diameter end (12) with a smaller diameter, the small diameter end (12) is provided with a thread on the outside, and the thread on the outer wall of the small diameter end (12) is opposite to the thread direction of the screw (11), the screw (11) and the small diameter end (12) are respectively threaded with a first nut (13) and a second nut (14) on the outside, and the screw (11) is provided with a hard spring (15) located between the first nut (13) and the second nut (14) on the outer sleeve.

8. A low temperature resistant explosion-proof power distribution device according to claim 7, characterized in that: The box body opening (2) is further provided with an outwardly extending edge (16) after protruding from the explosion-proof distribution box body (1); the fastening screw assembly fixes the box cover door (4) to the edge (16); and the first nut (13) is closely attached to the side of the edge (16).

9. A low temperature resistant explosion-proof power distribution device according to claim 8, characterized in that: The first nut (13) and the second nut (14) are provided with a positioning mechanism for positioning the hard spring (15).

10. A low temperature resistant explosion-proof power distribution device according to claim 9, characterized in that: The positioning mechanism comprises a first plug hole (17) and a second plug hole (18) respectively on the first nut (13) and the second nut (14); a first plug (19) and a second plug (20) extending parallel to the spiral axis are provided at both ends of the hard spring (15); the first plug (19) and the second plug (20) are respectively inserted into the first plug hole (17) and the second plug hole (18) and tightly fit with the inner walls thereof.

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