Lubricating and ventilating system for reduction gearbox

Abstract

The invention belongs to the technical field of reduction gearbox lubrication, and particularly discloses a reduction gearbox lubrication ventilation system which comprises a lubrication structure and a ventilation structure, the lubrication structure comprises an oil collection part, and an oil blocking rib is arranged above the oil collection part; a mounting groove is formed in the shell; the oil collecting piece comprises two side plates and an end plate, the two sides of the two side plates in the length direction are fixed, and the widths of the two side plates are gradually increased; the end plates are fixed to the small-width sides of the two side plates, and the large-width sides of the two side plates are installed in the installation grooves. An oil collecting groove is formed among the side plate, the end plate and the shell; the oil baffle rib is fixed in the shell and is positioned in the oil collecting groove; the end plate is fixed with the oil baffle rib; an oil inlet channel is reserved between the oil collecting groove and the shell; an oil passing hole is formed in the lowest position of the side plate; and the ventilation structure is arranged on the oil baffle rib. The lubricating system which is simple and reliable in structure is constructed by adding the oil collecting piece, matching with the oil blocking rib and adding the oil duct integrated on the shell and the gear shaft, and the lubricating effect of the reduction gearbox on a limit ramp can be obviously improved.

Description

Technical Field

[0001] The invention belongs to the technical field of reduction gearbox lubrication, and in particular relates to a reduction gearbox lubrication ventilation system. Background Art

[0002] The lubrication status of the gears and bearings of the automobile reduction gearbox under operating conditions is not only related to the power transmission efficiency, but also to the service life of the reduction gearbox. At present, in the field of commercial reduction gearboxes, splash lubrication is still a common choice. However, for reduction gearboxes that are arranged front and back on the vehicle and have large longitudinal dimensions, how to ensure good lubrication on ramps is often a pain point in the design and a key consideration affecting the reduction gearbox solution. Therefore, how to ensure good lubrication on ramps through a simple and reliable solution is a question worth considering. Summary of the invention

[0003] The purpose of the present invention is to provide a reduction gearbox lubrication and ventilation system. By adding oil collecting parts, assisted by oil retaining ribs on the housing, and adding oil channels integrated on the housing and the gear shaft, a simple and reliable lubrication system is constructed, which can significantly improve the lubrication effect of the reduction gearbox on extreme ramps.

[0004] In order to achieve the above-mentioned purpose, the technical solution of the present invention is: a reduction gearbox lubrication and ventilation system, including a lubrication structure and a ventilation structure, the lubrication structure including at least one group of oil collecting parts, each group of oil collecting parts is provided with at least one group of oil retaining ribs above; the interior of the reduction gearbox housing is provided with a mounting groove for installing the oil collecting parts, the mounting groove is located above the gear set; the oil collecting part includes two side plates and an end plate, the two sides of the two side plates in the length direction are fixed and the two side plates are not in a straight line, and the width of the two side plates along their length direction gradually increases; the end plate is fixed on the side with a smaller width of the two side plates, and the side with a larger width of the two side plates is installed in the mounting groove; the open ends of the two side plates are located on the side away from the gear set, and the side where the two side plates are connected to each other is located at the lowest position, and the side where the two side plates are connected to each other is inclined and the side close to the end plate is higher than the other side; the side plates, An oil collecting groove is formed between the end plate and the shell, and the oil baffle is fixed in the reduction gear housing and is located inside the oil collecting groove; the end plate is fixed to the oil baffle; an oil inlet channel is left between the upper side of the oil collecting groove and the shell, and the lubricating oil splashed when the gear set rotates will enter the oil collecting groove through the oil inlet channel; an oil through hole is provided at the lowest position of the side plate, and an oil channel is provided on the shell and the gear shaft, and the oil channel is connected with the oil through hole, and the oil channel is used to transport the lubricating oil to the position requiring lubrication; the oil baffle is used to block the splashed lubricating oil and guide it downward into the oil collecting groove; a connecting hole is provided at the position of the shell facing the oil baffle, and a ventilation structure is installed on the oil baffle through the connecting hole, and a ventilation channel is provided on the oil baffle, and two ventilation ports of the ventilation channel are respectively located on the upper and lower sides of the oil baffle, and the ventilation structure is connected to the ventilation port located on the upper side of the oil baffle.

[0005] Furthermore, a horizontal positioning plate is fixed to the end of the wider side of the two side panels, and a plurality of positioning constraint ribs are provided above the bottom of the mounting groove; between the bottom of the mounting groove and the positioning constraint ribs is an installation area for installing the positioning plate, and the positioning plate is interference fit with the installation area.

[0006] Furthermore, the end plate and the oil retaining rib are connected by bolts.

[0007] Furthermore, the oil collecting parts are provided with two groups, namely a first oil collecting part and a second oil collecting part, the first oil collecting part is located above the input shaft assembly and the intermediate shaft assembly and the side where the two side plates of the first oil collecting part are connected to each other is located above the intermediate shaft assembly; the second oil collecting part is located between the output shaft assembly and the intermediate shaft assembly; an oil guide rib is provided on a side plate of the first oil collecting part close to the input shaft assembly; two groups of oil baffle ribs are correspondingly provided in the first oil collecting part, one group of the oil baffle ribs corresponds to the position where the two side plates of the first oil collecting part are connected to each other, and the other group of the oil baffle ribs corresponds to the oil guide ribs; the oil through hole is provided on one side of the oil guide rib and the position of the oil through hole is higher than the oil guide rib.

[0008] Furthermore, a first oil passage is provided in the gear shaft of the intermediate shaft assembly; three groups of second oil passages are provided on the housing, the three groups of second oil passages correspond to the three groups of oil holes respectively, and the second oil passages on both sides respectively transport lubricating oil to the bearings of the input shaft assembly and the bearings of the output shaft assembly; the middle second oil passage is connected to the first oil passage, and the end of the middle second oil passage is used to transport lubricating oil to the bearings at the end of the intermediate shaft assembly; an oil outlet hole is provided on the gear shaft, and the position of the oil outlet hole corresponds to the position of the bearing; an oil guide pipe is connected to the oil outlet hole, and the oil guide pipe is used to transport lubricating oil to the bearings of the intermediate shaft assembly.

[0009] Furthermore, an oil seal is provided at the connection position between the first oil passage and the second oil passage.

[0010] Further, the angle formed between the two side plates of the first oil collecting member is an obtuse angle.

[0011] Furthermore, the bottom of the oil retaining rib is an inclined structure, and one side of the inclined structure close to the end plate is higher than the other side.

[0012] Furthermore, the ventilation structure adopts a ventilation plug.

[0013] The working principle and beneficial effect of this technical solution are: the lubricating oil moves under the stirring of the gear set, and under the action of the inner wall of the shell, a considerable part of the lubricating oil will move along the wall to the upper part of the shell. At this time, under the action of the oil retaining ribs on the top of the shell, the movement of the lubricating oil will be blocked and fall into the oil collecting tank under the action of gravity. A straight section design (positioning plate) is adopted at the bottom of the oil collecting tank to form an interference fit with several groups of positioning and restraining ribs on the shell. At the same time, under the action of the interference pressure, an effective sealing width is formed with the shell to reduce the leakage of lubricating oil on the extreme slope, and combined with the bolts on the top to fix the oil collecting part on the shell. The two side plates of the first oil collecting part adopt a large-angle pyramid design to ensure that the lubricating oil can still be collected to the corresponding oil hole under the designed extreme slope state, and the lubricating oil is collected and distributed to the designated position under the coordinated arrangement between the oil retaining ribs, the side plates and the oil guide ribs. The lubricating oil reaching the oil hole position at the bottom of the oil collecting tank is distributed to the corresponding required position through the oil channel integrated on the shell and the gear shaft. The connection position between the first oil channel and the second oil channel is sealed by an oil seal, which avoids leakage here under extreme slope conditions and ensures the lubrication effect. In addition, under the joint action of the oil collecting tank, the housing, and the oil retaining rib, a semi-enclosed cavity is formed. There is no air pressure difference between the cavity and the reduction box cavity, and the flow direction of the lubricating oil in the cavity is relatively simple, and there is almost no radial outward oil flow, especially in the plane area below the oil retaining rib. There is almost no oil flow at this position, and it is a very suitable choice to set a vent valve here. In addition, due to the existence of such a large volume of oil collecting tank, under high speed conditions, a considerable volume of lubricating oil will accumulate in the oil collecting tank, which reduces the lubricating oil at the bottom of the reduction box, and the corresponding gear set will reduce the oil stirring resistance, thereby improving the efficiency of the reduction box. By adding oil collecting parts through a simple assembly and fixing method, supplemented by the cooperation of oil retaining ribs and oil guide ribs, and the oil channels integrated on the housing and the gear shaft, a reducer lubrication and ventilation composite system with the function of solving extreme slope lubrication and reducing oil stirring loss is constructed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a first stereoscopic view of the reduction gearbox;

[0015] Figure 2 is a second stereoscopic view of the reduction gearbox;

[0016] Figure 3 is a perspective view of the reduction gearbox;

[0017] Figure 4 for Figure 1 The main view;

[0018] Figure 5 for Figure 1 Side view of

[0019] Figure 6for Figure 3 Schematic diagram of the structure of the oil collection parts;

[0020] Figure 7 for Figure 4 Sectional view of AA in the middle;

[0021] Figure 8 for Figure 5 Cross-sectional view of the middle BB;

[0022] Fig. 9 for Figure 5 Cross-sectional view of CC;

[0023] Fig.10 for Figure 7 A partial enlarged view of . DETAILED DESCRIPTION

[0024] The following is further described in detail through specific implementation methods:

[0025] The figure marks in the drawings of the specification include: housing 1, input shaft assembly 2, intermediate shaft assembly 3, output shaft assembly 4, first oil collecting part 5, second oil collecting part 6, ventilation structure 7, bolt 8, side plate 9, oil inlet channel 10, end plate 11, positioning plate 12, second oil channel 13, branch pipe 14, oil hole 15, oil blocking rib 16, oil guide rib 17, positioning restraining rib 18, oil seal 19, first oil channel 20, inclined surface structure 21, ventilation channel 22.

[0026] 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.

[0027] The embodiment is basically as shown in the attached Figure 1-10 As shown: A reduction gearbox lubrication and ventilation system, such as Figure 1-4 As shown, it includes a lubrication structure and a ventilation structure 7, and the lubrication structure includes at least one set of oil collecting parts (numbers 5 and 6 in the figure). At least one set of oil retaining ribs 16 is provided above each set of oil collecting parts. The interior of the reduction gearbox housing 1 is provided with a mounting groove for mounting the oil collecting parts, and the mounting groove is located above the gear set. Figure 6As shown, the oil collecting part includes two side plates 9 and an end plate 11. The two sides of the two side plates 9 in the length direction are fixed and the two side plates 9 are not in a straight line, and a certain angle is formed between the two side plates 9. The widths of the two side plates 9 along their length direction gradually increase; the end plate 11 is fixed to the side with a smaller width of the two side plates 9, and the end plate 11 is connected to the oil retaining rib 16 by bolts 8. The entire oil collecting part forms a triangular pyramid structure with one side open. The wider side of the two side plates 9 is installed in the mounting groove. Specifically, a horizontal positioning plate 12 is fixed to the end of the wider side of the two side plates 9, and a plurality of groups of positioning constraint ribs 18 are provided above the bottom of the mounting groove, such as Figure 3 , 9 As shown. The installation area for installing the positioning plate 12 is between the bottom of the installation groove and the positioning constraint rib 18. The positioning plate 12 is interference-fitted with the installation area. The open ends of the two side plates 9 are located on the side away from the gear set (that is, on the upper side), and the side where the two side plates 9 are connected to each other is located at the lowest position (that is, on the lower side). The side where the two side plates 9 are connected to each other is inclined and the side close to the end plate 11 is higher than the other side (such as Figure 1 , 4 An oil collecting groove is formed between the side plate 9, the end plate 11 and the housing 1, and the oil retaining rib 16 is fixed in the reduction gearbox housing 1 and is located inside the oil collecting groove, such as Figure 3 , 8 As shown in Figure 9, the oil retaining rib 16 is used to block the splashed lubricating oil and guide it downward into the oil collecting tank.

[0028] like Figure 7 , 10 As shown, an oil inlet channel 10 is left between the upper side of the oil collecting tank and the housing 1, and the lubricating oil splashed when the gear set rotates will enter the oil collecting tank through the oil inlet channel 10. The lowest position of the side plate 9 is provided with an oil hole 15 (such as Figure 6 , 9 As shown in the figure, the housing 1 and the gear shaft are provided with oil passages (such as numbers 13 and 20 in the figure), the oil passages are connected to the oil holes 15, and the oil passages are used to transport the lubricating oil to the position that needs lubrication. Figure 3 , 8 As shown, a connecting hole is provided at the position of the shell 1 facing the oil retaining rib 16, and a ventilation structure 7 (specifically a vent plug) is installed on the oil retaining rib 16 through the connecting hole. A ventilation channel 22 is provided on the oil retaining rib 16, and two ventilation ports of the ventilation channel 22 are respectively located on the upper and lower sides of the oil retaining rib 16, and the ventilation structure 7 is connected to the ventilation port located on the upper side of the oil retaining rib 16.

[0029] like Figure 6 As shown, in this embodiment, two groups of oil collecting members are provided, namely, a first oil collecting member 5 and a second oil collecting member 6. The angle formed between the two side plates 9 of the first oil collecting member 5 is an obtuse angle, and the angles of the two side plates 9 of the second oil collecting member 6 are arranged according to the space in the housing 1. Figure 4 As shown, the first oil collecting member 5 is located above the input shaft assembly 2 and the intermediate shaft assembly 3, and the side where the two side plates 9 of the first oil collecting member 5 are connected to each other is located above the intermediate shaft assembly 3; the second oil collecting member 6 is located between the output shaft assembly 4 and the intermediate shaft assembly 3. Figure 6 , 8 As shown in , 9 , an oil guide rib 17 is provided on a side plate 9 of the first oil collecting member 5 close to the input shaft assembly 2; two groups of oil baffle ribs 16 are correspondingly provided in the first oil collecting member 5, one group of oil baffle ribs 16 corresponds to the position where the two side plates 9 of the first oil collecting member 5 are connected to each other, and the other group of oil baffle ribs 16 corresponds to the oil guide rib 17; an oil through hole 15 is provided on one side of the oil guide rib 17 and the position of the oil through hole 15 is higher than the oil guide rib 17.

[0030] like Figure 3 , 6 As shown in , 7 and 9, a first oil passage 20 is provided in the gear shaft of the intermediate shaft assembly 3; three groups of second oil passages 13 are provided on the housing 1, and the three groups of second oil passages 13 correspond to the three groups of oil holes 15 respectively, and the second oil passages 13 on both sides respectively deliver lubricating oil to the bearings of the input shaft assembly 2 and the bearings of the output shaft assembly 4; the middle second oil passage 13 is connected to the first oil passage 20 through a branch pipe 14, and an oil seal 19 is provided at the connection position between the first oil passage 20 and the branch pipe 14. The end of the middle second oil passage 13 is used to deliver lubricating oil to the bearing at the end of the intermediate shaft assembly 3; an oil outlet hole is provided on the gear shaft, and the position of the oil outlet hole corresponds to the position of the bearing; an oil guide pipe is connected to the oil outlet hole, and the oil guide pipe is used to deliver lubricating oil to the bearing of the intermediate shaft assembly 3.

[0031] like Figure 8 As shown, the bottom of the oil retaining rib 16 is an inclined surface structure 21 and one side of the inclined surface structure 21 close to the end plate 11 is higher than the other side.

[0032] The specific implementation process is as follows:

[0033] The lubricating oil moves under the stirring of the gear set. Under the action of the inner wall of the housing 1, a considerable part of the lubricating oil will move along the wall to the upper part of the housing 1. At this time, under the action of the oil retaining rib 16 on the top of the housing 1, the movement of the lubricating oil will be blocked and fall into the oil collecting tank under the action of gravity. A straight section design (positioning plate 12) is adopted at the bottom of the oil collecting tank to form an interference fit with several groups of positioning and restraining ribs 18 on the housing 1. At the same time, under the action of the interference pressure, an effective sealing width is formed with the housing 1 to reduce the leakage of lubricating oil on the extreme slope, and combined with the bolts 8 on the top to fix the oil collecting part on the housing 1. The two side plates 9 of the first oil collecting part 5 adopt a large-angle pyramid design to ensure that the lubricating oil can still be collected at the corresponding oil hole 15 under the designed extreme slope state, and the lubricating oil is collected and distributed to the designated position under the coordinated arrangement between the oil retaining rib 16, the side plate 9 and the oil guide rib 17. The lubricating oil reaching the oil hole 15 at the bottom of the oil collecting tank is distributed to the corresponding required position through the oil channel integrated on the housing 1 and the gear shaft. The oil seal 19 is used to seal the connection between the first oil passage 20 and the second oil passage 13, thereby avoiding leakage at this location under extreme slope conditions and ensuring the lubrication effect. In addition, under the joint action of the oil collecting tank, the housing 1, and the oil retaining rib 16, a semi-enclosed cavity is formed. There is no pressure difference between the cavity and the reduction box cavity, and the flow direction of the lubricating oil in the cavity is relatively simple, and there is almost no radial outward oil flow, especially in the plane area below the middle oil retaining rib 16. There is almost no oil flow at this location, and it is a very suitable choice to set a vent valve here. In addition, due to the existence of such a large-volume oil collecting tank, under high-speed conditions, a considerable volume of lubricating oil will accumulate in the oil collecting tank, which reduces the lubricating oil at the bottom of the reduction box, and the corresponding gear set oil stirring resistance will be reduced, thereby improving the efficiency of the reduction box. By adding oil collecting parts in a simple assembly and fixing manner, with the cooperation of oil retaining ribs 16 and oil guiding ribs 17, and the oil channels integrated on the housing 1 and the gear shaft, a reducer lubrication and ventilation composite system is constructed to solve the problem of extreme slope lubrication and reduce oil churning losses.

[0034] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0035] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A reduction gearbox lubrication and ventilation system, characterized in that: The invention comprises a lubrication structure and a ventilation structure (7), wherein the lubrication structure comprises at least one group of oil collecting parts, and at least one group of oil retaining ribs (16) is arranged above each group of oil collecting parts; a mounting groove for mounting the oil collecting parts is arranged inside the reduction gearbox housing (1), and the mounting groove is located above the gear set; the oil collecting parts comprise two side plates (9) and an end plate (11), the two sides of the two side plates (9) in the length direction are fixed and the two side plates (9) are not in a straight line, and the width of the two side plates (9) along the length direction thereof gradually increases; The end plate (11) is fixed to the side of the two side plates (9) with a smaller width, and the side of the two side plates (9) with a larger width is installed in the installation groove; the open ends of the two side plates (9) are located on the side away from the gear set, and the side where the two side plates (9) are connected to each other is located at the lowest position, and the side where the two side plates (9) are connected to each other is inclined and the side close to the end plate (11) is higher than the other side; an oil collecting groove is formed between the side plate (9), the end plate (11) and the housing (1), and the oil retaining rib (16) is fixed to the side plate (9). The gearbox housing (1) is located inside the oil collecting groove; the end plate (11) is fixed to the oil retaining rib (16); an oil inlet channel (10) is reserved between the upper side of the oil collecting groove and the housing (1), and the lubricating oil splashed when the gear set rotates will enter the oil collecting groove through the oil inlet channel (10); an oil hole (15) is provided at the lowest position of the side plate (9), and an oil passage is provided on the housing (1) and the gear shaft, and the oil passage is connected to the oil hole (15), and the oil passage is used to transport the lubricating oil to the gears that need to be lubricated. The oil retaining rib (16) is used to block splashed lubricating oil and guide it downward into the oil collecting tank; the shell (1) is provided with a connecting hole at a position opposite to the oil retaining rib (16); the ventilation structure (7) is installed on the oil retaining rib (16) through the connecting hole; the oil retaining rib (16) is provided with a ventilation channel (22); two ventilation ports of the ventilation channel (22) are respectively located on the upper and lower sides of the oil retaining rib (16); the ventilation structure (7) is connected to the ventilation port located on the upper side of the oil retaining rib (16).

2. A reduction gearbox lubrication and ventilation system according to claim 1, characterized in that: A horizontal positioning plate (12) is fixed to the end of the wider side of the two side plates (9), and a plurality of groups of positioning and restraining ribs (18) are provided above the bottom of the installation groove; between the bottom of the installation groove and the positioning and restraining ribs (18) is an installation area for installing the positioning plate (12), and the positioning plate (12) is interference-fitted with the installation area.

3. A reduction gearbox lubrication and ventilation system according to claim 1, characterized in that: The end plate (11) and the oil retaining rib (16) are connected via bolts (8).

4. A reduction gearbox lubrication and ventilation system according to claim 1, characterized in that: The oil collecting member is provided with two groups, namely a first oil collecting member (5) and a second oil collecting member (6). The first oil collecting member (5) is located above the input shaft assembly (2) and the intermediate shaft assembly (3), and the side where the two side plates (9) of the first oil collecting member (5) are connected to each other is located above the intermediate shaft assembly (3); the second oil collecting member (6) is located between the output shaft assembly (4) and the intermediate shaft assembly (3); an oil guide rib (17) is provided on a side plate (9) of the first oil collecting member (5) close to the input shaft assembly (2); two groups of oil blocking ribs (16) are correspondingly provided in the first oil collecting member (5), one group of the oil blocking ribs (16) corresponds to the position where the two side plates (9) of the first oil collecting member (5) are connected to each other, and the other group of the oil blocking ribs (16) corresponds to the oil guide rib (17); the oil through hole (15) is provided on one side of the oil guide rib (17), and the position of the oil through hole (15) is higher than the oil guide rib (17).

5. A reduction gearbox lubrication and ventilation system according to claim 4, characterized in that: A first oil passage (20) is provided in the gear shaft of the intermediate shaft assembly (3); three groups of second oil passages (13) are provided on the housing (1), the three groups of second oil passages (13) respectively correspond to the three groups of oil holes (15), and the second oil passages (13) on both sides respectively transport lubricating oil to the bearings of the input shaft assembly (2) and the bearings of the output shaft assembly (4); the middle second oil passage (13) is connected to the first oil passage (20), and the end of the middle second oil passage (13) is used to transport lubricating oil to the bearings at the end of the intermediate shaft assembly (3); an oil outlet hole is provided on the gear shaft, and the position of the oil outlet hole corresponds to the position of the bearing; an oil guide pipe is connected to the oil outlet hole, and the oil guide pipe is used to transport lubricating oil to the bearings of the intermediate shaft assembly (3).

6. A reduction gearbox lubrication and ventilation system according to claim 5, characterized in that: An oil seal (19) is provided at the connection position between the first oil passage (20) and the second oil passage (13).

7. A reduction gearbox lubrication and ventilation system according to claim 4, characterized in that: The angle formed between the two side plates (9) of the first oil collecting member (5) is an obtuse angle.

8. A reduction gearbox lubrication and ventilation system according to claim 4, characterized in that: The bottom of the oil retaining rib (16) is an inclined surface structure (21), and the side of the inclined surface structure (21) close to the end plate (11) is higher than the other side.

9. A reduction gearbox lubrication and ventilation system according to claim 1, characterized in that: The ventilation structure (7) adopts a ventilation plug.

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