Gearbox for nitrogen compressor

Abstract

The utility model discloses a gear box for nitrogen compressor, including gear box body, input shaft, low speed axle and high speed axle, the input shaft is equipped with in the horizontal longitudinal through -going of the middle position of the section in gear box body, and is equipped with bearing III on the input shaft before and after interval, and the input shaft is rotatively connected with gear box body through bearing III, the low speed axle is equipped with in the horizontal longitudinal through -going of the section relative to the left side of input shaft in gear box body, and is equipped with bearing I on the low speed axle before and after interval, and the low speed axle is rotatively connected with gear box body through bearing I, the high speed axle is equipped with in the horizontal longitudinal through -going of the section relative to the right side of input shaft in gear box body, and is equipped with bearing II on the high speed axle before and after interval, and the high speed axle is connected with gear box body through bearing II, be equipped with lubricating assembly in gear box body, and realize lubrication through lubricating assembly and introduce lubricating oil to corresponding bearing I, bearing II and bearing III. The utility model discloses lubricating oil road hidden form design, avoids the risk of oil leakage.

Description

Technical Field

[0001] This utility model relates to the field of compressor technology, specifically to a gearbox for a nitrogen compressor. Background Technology

[0002] Compressed nitrogen is a colorless and odorless inert gas that is widely used in various fields such as industrial production, food, and medicine. Some fields require oil-free and clean nitrogen, so nitrogen compressors play an important role as a crucial component.

[0003] The gearbox is part of a nitrogen compressor, and its function is to increase speed, transmit power, and drive the impeller to rotate and perform work. During operation, the gearbox requires forced lubrication via a thin oil station. Traditional gearbox lubrication systems use steel pipes connected to the gearbox housing, either inside or outside. However, oil leaks frequently occur at the pipe joints, as well as at the split between the upper and lower housings and at the oil seals. Therefore, these problems urgently need to be addressed. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a gearbox for a nitrogen compressor, which has a simple structure and is easy to maintain. It adopts a concealed lubrication circuit design, which is both aesthetically pleasing and avoids the risk of oil leakage.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The innovative feature of this utility model is that it includes a gearbox body, an input shaft, a low-speed shaft, a high-speed shaft, and a lubrication assembly; the input shaft is horizontally and longitudinally inserted through the middle of the split surface of the gearbox body, which is arranged vertically and horizontally; bearings III are symmetrically and coaxially sleeved on the input shaft relative to the interior of the gearbox body; the input shaft is rotatably connected to the gearbox body around its own axial direction via bearings III; a low-speed shaft is horizontally and longitudinally inserted through the middle surface of the gearbox body relative to the left side of the input shaft; and a low-speed shaft is mounted on the low-speed shaft relative to the gearbox body... The gearbox body is also equipped with bearings I, which are symmetrically spaced and coaxially fitted together. The low-speed shaft is rotatably connected to the gearbox body through bearings I around its own axis. A high-speed shaft is also horizontally and longitudinally inserted through the middle surface of the gearbox body relative to the right side of the input shaft. Bearings II are also symmetrically spaced and coaxially fitted together on the high-speed shaft relative to the inside of the gearbox body. The high-speed shaft is rotatably connected to the gearbox body through bearings II around its own axis. Both the low-speed shaft and the high-speed shaft rotate synchronously with the input shaft. A lubrication assembly is also provided in the gearbox body, and lubricating oil is introduced into the corresponding bearings I, II, and III through the lubrication assembly to achieve lubrication.

[0006] Preferably, the gearbox body includes an upper housing, an upper flange, a lower housing, and a lower flange; the upper housing and the lower housing are both vertically and horizontally arranged hollow cavities, and they are matched; the lower surface of the upper housing is open, and a matching upper flange is horizontally attached to its lower surface, and the two are integrally formed; the upper surface of the lower housing is open, and a matching lower flange is horizontally attached to its upper surface, and the two are integrally formed; the upper housing and the lower housing are vertically aligned, and the upper housing and the lower housing are screwed together and fixedly assembled into the gearbox body by the alignment and screwing of the upper flange and the lower flange.

[0007] Preferably, the upper flange and the lower flange are matching rectangular structures, and a square clearance groove I is vertically embedded and opened through the middle of the lower surface of the upper flange, which ensures that the upper flange and the upper housing do not interfere with the rotation of the input shaft, the low-speed shaft and the high-speed shaft; a square clearance groove II is vertically embedded and opened through the middle of the upper surface of the lower flange, which also ensures that the lower flange and the lower housing do not interfere with the rotation of the input shaft, the low-speed shaft and the high-speed shaft.

[0008] Preferably, the shaft further includes a large gear, a small gear I, and a small gear II; a large gear is coaxially and fixedly mounted on the input shaft at the middle position and between the two bearings III; a small gear I matching the large gear is coaxially and fixedly mounted on the low-speed shaft relative to the position of the large gear, the small gear I being spaced apart between the two bearings I, and the low-speed shaft rotating synchronously with the input shaft through the meshing of the small gear I and the large gear; a small gear II matching the large gear is coaxially and fixedly mounted on the high-speed shaft relative to the position of the large gear, the small gear II being spaced apart between the two bearings II, and the high-speed shaft rotating synchronously with the input shaft through the meshing of the small gear II and the large gear.

[0009] Preferably, a rectangular annular vertically embedded labyrinth sealing groove matching the sealing ring is provided on the upper surface of the lower flange relative to the outer side of the clearance groove II. The labyrinth sealing groove is centrally located on the lower flange. The labyrinth sealing groove is discontinuous relative to the positions of each bearing I, bearing II, and bearing III. Through the cooperation of the sealing ring and the labyrinth sealing groove, the sealing ring covers the entire sealing surface to ensure the sealing performance when the upper flange and the lower flange are screwed together, and to ensure that the sealing ring does not interfere with the rotation of the low-speed shaft, input shaft, and high-speed shaft.

[0010] Preferably, it also includes an oil pump; the oil pump is connected to one end of the input shaft via a coupling, and the rotation of the input shaft drives the oil pump to work, thereby introducing lubricating oil through the lubrication assembly to the corresponding bearings I, II and III to achieve lubrication.

[0011] Preferably, it further includes an oil seal, sealing teeth, shoulder I, shoulder II, and shoulder III; an oil seal is coaxially spaced on the low-speed shaft relative to the outer side of each bearing I and on the high-speed shaft relative to the outer side of each bearing II, each oil seal being installed at a corresponding position on the gearbox body, and having sealing teeth coaxially spaced inside, ensuring that the sealing teeth and oil seal do not interfere with the rotation of the corresponding low-speed shaft or high-speed shaft; on the low-speed shaft relative to the outer side of each bearing I and on the high-speed shaft relative to each bearing II... II. On the outer side, from the inside out, shoulder III, shoulder II, and shoulder I are coaxially and fixedly connected at intervals. Each shoulder I is located on the outer side of the corresponding oil seal and is used to prevent the internal air pressure of the compressor from affecting the seal of the gearbox body. Each shoulder II is coaxially and spaced inside the corresponding oil seal and is set without interfering with the corresponding sealing teeth, thus acting as an oil-slinging ring. Each shoulder III is located on the inner side of the corresponding oil seal and is used to block oil leakage from the side of the corresponding bearing I or bearing II.

[0012] Preferably, an oil return groove is vertically embedded through the upper surface of the lower flange relative to each shoulder III position, and each oil return groove is connected to the interior of the lower housing; an oil return hole is also embedded radially on the inner circumferential surface of each oil seal, and one end of each oil return hole extends to the inner end face of the corresponding oil seal, thereby allowing the leaked lubricating oil to flow back into the lower housing in sequence through the oil return hole and the oil return groove.

[0013] Preferably, oil inlets are horizontally and vertically embedded on the left and right end faces of the upper flange, respectively, and the oil pump is sealed and connected to the corresponding oil inlet through an oil pipe, pumping lubricating oil into the corresponding oil inlet. A rectangular annular main oil passage is horizontally embedded in the upper flange at the same horizontal plane as the oil inlets, and the two oil inlets are respectively connected to the main oil passage. Branch oil passages are horizontally embedded in the upper flange at the same horizontal plane as the oil inlets and at the positions of each bearing I, bearing II, and bearing III, and each branch oil passage is connected to the main oil passage. An oil passage hole is vertically embedded on the lower surface of the upper flange at the position of each branch oil passage, and each oil passage hole is connected to the corresponding branch oil passage, thereby allowing lubricating oil to be introduced into the corresponding bearing I, bearing II, and bearing III in sequence through the main oil passage, branch oil passage, and oil passage hole for lubrication.

[0014] The beneficial effects of this utility model are: (1) This utility model has a simple structure and is easy to maintain. It adopts a concealed lubrication oil circuit design, which is both aesthetically pleasing and avoids the risk of oil leakage. (2) This utility model uses a labyrinth sealing groove and a sealing ring to seal between the upper flange and the lower flange, thus ensuring sealing performance; (3) This utility model facilitates the introduction of lubricating oil into the corresponding bearing through the combination of the main oil circuit, branch oil circuit and oil passage hole; and through the combination of oil seal, sealing tooth, shoulder I, shoulder II, shoulder III, oil return hole and oil return groove, excess lubricating oil on the shaft can be returned to the lower housing, thereby eliminating oil leakage. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a gearbox for a nitrogen compressor according to the present invention.

[0017] Figure 2 for Figure 1 AA view.

[0018] Figure 3 for Figure 2 Enlarged schematic diagram of part B.

[0019] Figure 4 for Figure 3 A schematic diagram of the structure of the oil seal section.

[0020] Figure 5 This is a structural schematic diagram of the upper flange part of this utility model.

[0021] Figure 6 This is a structural schematic diagram of the lower flange part of this utility model.

[0022] Among them, 1-upper housing; 2-upper flange; 3-lower housing; 4-lower flange; 5-input shaft; 6-bearing III; 7-oil pump; 8-large gear; 9-low-speed shaft; 10-small gear I; 11-bearing I; 12-high-speed shaft; 13-small gear II; 14-bearing II; 15-labyrinth seal groove; 16-oil seal; 17-shoulder I; 18-shoulder II; 19-shoulder III; 20-oil return hole; 21-oil return groove; 22-oil inlet; 23-main oil passage; 24-branch oil passage; 25-oil passage; 26-sealing tooth; 27-avoidance groove I; 28-avoidance groove II. Detailed Implementation

[0023] The technical solution of this utility model will be clearly and completely described below through specific embodiments.

[0024] This utility model discloses a gearbox for a nitrogen compressor, comprising a gearbox body, an input shaft 5, a low-speed shaft 9, a high-speed shaft 12, and a lubrication assembly; the specific structure is as follows: Figures 1-6 As shown, an input shaft 5 is horizontally and longitudinally inserted through the center of the split surface of the gearbox body, which is arranged vertically and horizontally. Bearings III 6 are symmetrically and coaxially fitted onto the input shaft 5 with respect to the interior of the gearbox body. The input shaft 5 is rotatably connected to the gearbox body around its own axial direction via bearings III 6. A low-speed shaft 9 is also horizontally and longitudinally inserted through the split surface of the gearbox body, relative to the left side of the input shaft 5. Bearings I 11 are symmetrically and coaxially fitted onto the low-speed shaft 9 with respect to the interior of the gearbox body. The low-speed shaft 9 is connected to the gearbox body via bearings I 11. The gearbox body is rotatably connected around its own axis; a high-speed shaft 12 is horizontally and longitudinally inserted through the middle surface of the gearbox body relative to the right side of the input shaft 5, and bearings II 14 are symmetrically and coaxially sleeved on the high-speed shaft 12 relative to the inside of the gearbox body. The high-speed shaft 12 is rotatably connected to the gearbox body around its own axis through bearings II 14, and both the low-speed shaft 9 and the high-speed shaft 12 rotate synchronously with the input shaft 5; a lubrication assembly is also provided in the gearbox body, and lubricating oil is introduced into the corresponding bearings I 11, II 14 and III 6 through the lubrication assembly to achieve lubrication.

[0025] The gearbox body of this utility model includes an upper housing 1, an upper flange 2, a lower housing 3, and a lower flange 4; as shown... Figures 1-6 As shown, both the upper housing 1 and the lower housing 3 are hollow cavities arranged vertically and horizontally, and they are matched. The lower surface of the upper housing 1 is open, and a matching upper flange 2 is horizontally attached to its lower surface, and the two are integrally formed. The upper surface of the lower housing 3 is open, and a matching lower flange 4 is horizontally attached to its upper surface, and the two are integrally formed. The upper housing 1 and the lower housing 3 are aligned vertically, and the upper housing 1 and the lower housing 3 are screwed together and assembled into the gearbox body by the alignment and screwing of the upper flange 2 and the lower flange 4.

[0026] like Figures 1-6 As shown, the upper flange 2 and the lower flange 4 are matching rectangular structures. A square clearance groove I27 is vertically embedded and opened in the middle of the lower surface of the upper flange 2. The clearance groove I27 ensures that the upper flange 2 and the upper housing 1 do not interfere with the rotation of the input shaft 5, the low-speed shaft 9, and the high-speed shaft 12. A square clearance groove II28 is vertically embedded and opened in the middle of the upper surface of the lower flange 4. The clearance groove II28 ensures that the lower flange 4 and the lower housing 3 do not interfere with the rotation of the input shaft 5, the low-speed shaft 9, and the high-speed shaft 12.

[0027] like Figures 1-6As shown, a large gear 8 is coaxially sleeved and fixed at the middle position on the input shaft 5, relative to the two bearings III6. A small gear I10 matching the large gear 8 is coaxially sleeved and fixed on the low-speed shaft 9, relative to the position of the large gear 8. The small gear I10 is spaced between the two bearings I11, and the meshing of the small gear I10 with the large gear 8 causes the low-speed shaft 9 to rotate synchronously with the input shaft 5. A small gear II13 matching the large gear 8 is coaxially sleeved and fixed on the high-speed shaft 12, relative to the position of the large gear 8. The small gear II13 is spaced between the two bearings II14, and the meshing of the small gear II13 with the large gear 8 causes the high-speed shaft 12 to rotate synchronously with the input shaft 5.

[0028] like Figures 1-6 As shown, a rectangular annular vertically embedded labyrinth sealing groove 15 matching the sealing ring is provided on the upper surface of the lower flange 4 relative to the outer side of the clearance groove II 28. The labyrinth sealing groove 15 is centrally located on the lower flange 4. The labyrinth sealing groove 15 is disconnected relative to the positions of each bearing I 11, bearing II 14, and bearing III 6. Through the cooperation of the sealing ring and the labyrinth sealing groove 15, the sealing ring covers the entire sealing surface to ensure the sealing performance when the upper flange 2 and the lower flange 4 are screwed together, and to ensure that the sealing ring does not interfere with the rotation of the low-speed shaft 9, the input shaft 5, and the high-speed shaft 12.

[0029] like Figures 1-6 As shown, the oil pump 7 is linked to one end of the input shaft 5 via a coupling. The rotation of the input shaft 5 drives the oil pump 7 to work, and the oil pump 7 then introduces lubricating oil through the lubrication assembly to the corresponding bearings I11, II14, and III6 for lubrication. This utility model does not require an additional drive motor; the rotation of the input shaft 5 is sufficient to drive the oil pump 7, thereby achieving the purpose of energy saving and emission reduction.

[0030] This utility model also provides oil seals 16 on the low-speed shaft 9 relative to the outer side of each bearing I 11, and on the high-speed shaft 12 relative to the outer side of each bearing II 14, which are coaxially spaced. Figures 1-6As shown, each oil seal 16 is installed at a corresponding position on the gearbox body, and a sealing tooth 26 is coaxially provided inside it, ensuring that the sealing tooth 26 and the oil seal 16 do not interfere with the rotation of the corresponding low-speed shaft 9 or high-speed shaft 12; on the low-speed shaft 9, relative to the outer side of each bearing I 11, and on the high-speed shaft 12, relative to the outer side of each bearing II 14, shoulders III 19, II 18, and I 17 are coaxially sleeved and fixed from the inside to the outside. Each shoulder I 17 is located on the outer side of the corresponding oil seal 16, and the shoulder I 17 is used to prevent the internal air pressure of the compressor from affecting the seal of the gearbox body; each shoulder II 18 is coaxially spaced inside the corresponding oil seal 16, and is set without interfering with the corresponding sealing tooth 26, thus acting as an oil slinger ring; each shoulder III 19 is located on the inner side of the corresponding oil seal 16, and the shoulder III 19 is used to block the oil leakage from the side of the corresponding bearing I 11 or bearing II 14.

[0031] like Figures 1-6 As shown, an oil return groove 21 is vertically embedded and penetrated on the upper surface of the lower flange 4 relative to each shoulder Ⅲ19, and each oil return groove 21 is connected to the interior of the lower housing 3; an oil return hole 20 is also embedded radially on the inner circumferential surface of each oil seal 16, and one end of each oil return hole 20 extends out of the inner end face of the corresponding oil seal 16, so that the leaked lubricating oil flows back to the lower housing 3 in sequence through the oil return hole 20 and the oil return groove 21.

[0032] This utility model has oil inlets 22 horizontally, laterally, and vertically embedded on the left and right end faces of the upper flange 2 near its upper end, respectively. Figures 1-6 As shown, the oil pump 7 is sealed and connected to the corresponding oil inlet 22 through oil pipes, and the oil pump 7 pumps lubricating oil into the corresponding oil inlet 22. A rectangular annular main oil passage 23 is also horizontally embedded in the upper flange 2 at the same horizontal plane as the oil inlet 22, and the two oil inlets 22 are respectively connected to the main oil passage 23. A branch oil passage 24 is also horizontally embedded in the upper flange 2 at the same horizontal plane as the oil inlet 22 and at the position of each bearing I 11, bearing II 14 and bearing III 6, and each branch oil passage 24 is respectively connected to the main oil passage 23. An oil passage hole 25 is also vertically embedded on the lower surface of the upper flange 2 at the position of each branch oil passage 24, and each oil passage hole 25 is connected to the corresponding branch oil passage 24, so that the lubricating oil is introduced into the corresponding bearing I 11, bearing II 14 and bearing III 6 in sequence through the main oil passage 23, branch oil passage 24 and oil passage hole 25 to achieve lubrication.

[0033] The working principle of this utility model: This invention connects one end of the input shaft 5 to the drive motor, and connects the two ends of the low-speed shaft 9 and the high-speed shaft 12 to the compressor impeller respectively, and connects the oil pump 7 to the oil inlet 22 through the oil pipe; at this time, the low-speed shaft 9 and the high-speed shaft 12 can be driven to rotate through the meshing of the large gear 8 and the small gear I 10, and the meshing of the large gear 8 and the small gear II 13, thereby driving the compressor impeller to rotate and do work; During this process, the rotation of the input shaft 5 drives the oil pump 7 to work, and the oil pump 7 introduces the lubricating oil from the oil inlet 22 through the main oil passage 23, the branch oil passage 24, and the oil passage 25 to the corresponding bearing for lubrication. The excess lubricating oil on the shaft is prevented from leaking by the cooperation of the oil seal 16, the sealing tooth 26, the shoulder I 17, the shoulder II 18, and the shoulder III 19, and then flows back to the lower housing 3 through the oil return hole 20 and the oil return groove 21.

[0034] The beneficial effects of this utility model are: (1) This utility model has a simple structure and is easy to maintain. It adopts a concealed lubrication oil circuit design, which is both aesthetically pleasing and avoids the risk of oil leakage. (2) This utility model uses a labyrinth sealing groove 15 and a sealing ring to seal between the upper flange 2 and the lower flange 4, thus ensuring the sealing performance; (3) The present invention facilitates the introduction of lubricating oil into the corresponding bearing through the cooperation of the main oil passage 23, the branch oil passage 24 and the oil passage 25; and through the cooperation of the oil seal 16, the sealing tooth 26, the shoulder I 17, the shoulder II 18, the shoulder III 19, the oil return hole 20 and the oil return groove 21, the excess lubricating oil on the shaft can be returned to the lower housing 3, thereby eliminating the oil leakage phenomenon.

[0035] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the concept and scope of the present utility model. Without departing from the design concept of the present utility model, all modifications and improvements made by those skilled in the art to the technical solutions of the present utility model should fall within the protection scope of the present utility model. The technical content for which protection is sought in the present utility model has been fully recorded in the technical requirements.

Claims

1. A gearbox for a nitrogen compressor, characterized in that: The gearbox includes a gearbox body, an input shaft, a low-speed shaft, a high-speed shaft, and a lubrication assembly. The input shaft is horizontally and longitudinally inserted through the center of the gearbox body, which is vertically and laterally positioned. Bearings III are symmetrically and coaxially fitted onto the input shaft with respect to the interior of the gearbox body. The input shaft is rotatably connected to the gearbox body around its own axial direction via bearings III. A low-speed shaft is also horizontally and longitudinally inserted through the center of the gearbox body, to the left of the input shaft. Bearings I are symmetrically and coaxially fitted onto the low-speed shaft with respect to the interior of the gearbox body with respect to the interior of the gearbox body. The low-speed shaft is rotatably connected to the gearbox body via bearing I. A high-speed shaft is horizontally and longitudinally inserted through the center plane of the gearbox body relative to the right side of the input shaft. Bearings II are symmetrically and coaxially sleeved on the high-speed shaft relative to the inside of the gearbox body. The high-speed shaft is rotatably connected to the gearbox body via bearings II. Both the low-speed shaft and the high-speed shaft rotate synchronously with the input shaft. A lubrication assembly is also provided in the gearbox body, and lubricating oil is introduced into the corresponding bearings I, II, and III through the lubrication assembly to achieve lubrication.

2. The gearbox for a nitrogen compressor according to claim 1, characterized in that: The gearbox body includes an upper housing, an upper flange, a lower housing, and a lower flange; both the upper and lower housings are vertically and horizontally arranged hollow cavities, and they are matched; the lower surface of the upper housing is open, and a matching upper flange is horizontally attached to its lower surface, and the two are integrally formed; the upper surface of the lower housing is open, and a matching lower flange is horizontally attached to its upper surface, and the two are integrally formed; the upper and lower housings are aligned vertically, and the upper and lower housings are screwed together and fixedly assembled into the gearbox body by the alignment and screwing of the upper and lower flanges.

3. A gearbox for a nitrogen compressor according to claim 2, characterized in that: The upper flange and the lower flange are matched rectangular structures. A square clearance groove I is vertically embedded and opened in the middle of the lower surface of the upper flange. The clearance groove I ensures that the upper flange and the upper housing do not interfere with the rotation of the input shaft, low-speed shaft and high-speed shaft. A square clearance groove II is vertically embedded and opened in the middle of the upper surface of the lower flange. The clearance groove II ensures that the lower flange and the lower housing do not interfere with the rotation of the input shaft, low-speed shaft and high-speed shaft.

4. A gearbox for a nitrogen compressor according to claim 1, characterized in that: It also includes a large gear, a small gear I, and a small gear II; a large gear is coaxially and fixedly mounted on the input shaft at the middle position and between the two bearings III; a small gear I matching the large gear is coaxially and fixedly mounted on the low-speed shaft relative to the position of the large gear, the small gear I is spaced between the two bearings I, and the low-speed shaft rotates synchronously with the input shaft through the meshing of the small gear I and the large gear; a small gear II matching the large gear is coaxially and fixedly mounted on the high-speed shaft relative to the position of the large gear, the small gear II is spaced between the two bearings II, and the high-speed shaft rotates synchronously with the input shaft through the meshing of the small gear II and the large gear.

5. A gearbox for a nitrogen compressor according to claim 3, characterized in that: On the upper surface of the lower flange, a rectangular annular vertically embedded labyrinth sealing groove matching the sealing ring is provided relative to the outer side of the clearance groove II. The labyrinth sealing groove is centrally located on the lower flange. The labyrinth sealing groove is discontinuous relative to the positions of each bearing I, bearing II, and bearing III. Through the cooperation of the sealing ring and the labyrinth sealing groove, the sealing ring covers the entire sealing surface to ensure the sealing performance when the upper and lower flanges are bolted together, and to ensure that the sealing ring does not interfere with the rotation of the low-speed shaft, input shaft, and high-speed shaft.

6. A gearbox for a nitrogen compressor according to claim 3, characterized in that: It also includes an oil pump; the oil pump is connected to one end of the input shaft via a coupling, and the rotation of the input shaft drives the oil pump to work, thereby introducing lubricating oil through the lubrication assembly to the corresponding bearings I, II and III to achieve lubrication.

7. A gearbox for a nitrogen compressor according to claim 6, characterized in that: It also includes oil seals, sealing teeth, shoulder I, shoulder II, and shoulder III; oil seals are coaxially spaced and sleeved on the low-speed shaft relative to the outer side of each bearing I, and on the high-speed shaft relative to the outer side of each bearing II. Each oil seal is installed at a corresponding position on the gearbox body, and has sealing teeth coaxially spaced inside it, ensuring that the sealing teeth and oil seals do not interfere with the rotation of the corresponding low-speed or high-speed shaft; on the low-speed shaft relative to the outer side of each bearing I, and on the high-speed shaft relative to the outer side of each bearing II... The sides are also provided with shoulders III, II and I, which are coaxially and fixedly connected from the inside to the outside. Each shoulder I is located on the outside of the corresponding oil seal and is used to prevent the internal air pressure of the compressor from affecting the seal of the gearbox body. Each shoulder II is coaxially and spaced inside the corresponding oil seal and is set without interfering with the corresponding sealing teeth, thus acting as an oil slinger. Each shoulder III is located on the inside of the corresponding oil seal and is used to block the oil leakage from the side of the corresponding bearing I or bearing II.

8. A gearbox for a nitrogen compressor according to claim 7, characterized in that: A return oil groove is vertically embedded through the upper surface of the lower flange relative to each shoulder III position, and each of the return oil grooves is connected to the interior of the lower housing; a return oil hole is also embedded radially on the inner circumferential surface of each oil seal, and one end of each return oil hole extends to the inner end face of the corresponding oil seal, thereby allowing the leaked lubricating oil to flow back into the lower housing in sequence through the return oil hole and the return oil groove.

9. A gearbox for a nitrogen compressor according to claim 6, characterized in that: Oil inlets are horizontally and vertically embedded on the left and right end faces of the upper flange, respectively. Oil pumps are sealed to the corresponding oil inlets via oil pipes, pumping lubricating oil into each inlet. A rectangular annular main oil passage is horizontally embedded in the upper flange at the same horizontal plane as the oil inlets, with the two oil inlets connected to the main oil passage. Branch oil passages are horizontally embedded in the upper flange at the same horizontal plane as the oil inlets and relative to each bearing I, bearing II, and bearing III, with each branch oil passage connected to the main oil passage. Oil through holes are vertically embedded on the lower surface of the upper flange relative to each branch oil passage, with each through hole connected to the corresponding branch oil passage. This allows lubricating oil to be sequentially introduced into the corresponding bearings I, bearing II, and bearing III via the main oil passage, branch oil passages, and oil through holes for lubrication.

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