Intelligent oil-immersed transformer protection cover

Abstract

The present application relates to the field of oil-immersed transformer protection, and particularly discloses an intelligent oil-immersed transformer protection cover, which comprises a foundation base plate, side protection plates movably sleeved on the top of the foundation base plate at the two side edge positions, a back protection plate movably sleeved on the top surface of the foundation base plate and located at one side edge position, a limiting top cover movably sleeved on the outer side surface of the top of the side protection plate and the back protection plate, and an oil-immersed transformer which is detachably installed on the inner side wall surface of the side protection plate. When the limiting top cover is overlapped on the top surface of the side protection plate, the butt joint limiting strips on the inner side wall surface of the limiting top cover are sleeved on the inner side wall surface of the butt joint limiting grooves, and the butt joint limiting strips are clamped on the inner side wall surface of the butt joint limiting grooves, so that the position of the butt joint limiting strips is limited by the butt joint limiting grooves, and the outer side surface of the inner clamping plate is attached to the inner side wall surface of the side protection plate by the thickness of the inner clamping plate.

Description

Technical Field

[0001] This invention belongs to the field of oil-immersed transformer protection technology, specifically an intelligent oil-immersed transformer protective cover. Background Technology

[0002] Oil-immersed transformers are a new type of high-performance transformer with a more rational structure and superior performance. Their three-dimensional wound core, with its three core columns arranged in an equilateral triangle, eliminates air gaps in the magnetic circuit, resulting in tighter winding, uniform and shortest lengths for the three magnetic circuits, and a cross-sectional area closer to a circle. This further improves performance, reduces losses and noise, achieves three-phase balance, and reduces third harmonic components. This product is more suitable for power grid upgrades in urban and rural areas, industrial and mining enterprises, and is also suitable for combined transformers and prefabricated substation transformers.

[0003] A patent with publication number CN113539620A discloses an oil-immersed transformer protective cover, comprising: a cover body, a buffer column at the bottom of the cover body and a door panel at the top, the door panel being inclined and fitting into the top of the cover body; a base inside the cover body, with a first mounting column on the upper part of the base; a second mounting column on the side of the first mounting column, the first mounting column being higher than the first mounting column; a drive rod on the upper part of the first mounting column; and a pushing mechanism on the upper part of the second mounting column. This invention uses the pushing mechanism to drive the drive rod to flip outwards, thereby opening the door panel to both sides. This operation is simple and quick, allowing for free operation. The height of the mounting plate is adjusted by moving a sliding block laterally on the surface of the adjusting screw, thereby changing the tilt angle of the lifting adjustment rod. The transformer body is located on the upper part of the mounting plate. This configuration allows for arbitrary adjustment of the transformer's height, facilitating maintenance.

[0004] In current technology, to prevent foreign objects from entering the transformer and causing accidents, and to protect personal safety, the transformer is usually installed in a protective cover. However, existing protective covers are positioned using screws or welding. During disassembly and transportation, the protective covers are in a large volume, which takes up too much space during transportation. Moreover, the protective covers may collide with each other during transportation, causing excessive shaking at the screw positioning points, which can lead to the screws bending and making them difficult to disassemble later.

[0005] Therefore, the present invention provides an intelligent oil-immersed transformer protective cover. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] The technical solution adopted by this invention to solve its technical problem is as follows: An intelligent oil-immersed transformer protective cover, comprising a foundation plate and side protective plates movably fitted onto the top edges of the foundation plate, a back protective plate movably fitted onto the top surface of the foundation plate and located at one edge, a limiting top cover movably fitted onto the outer top surfaces of the side and back protective plates, and an oil-immersed transformer detachably installed on the inner wall of the side protective plates. One side surface of the side protective plate is movably fitted onto the outer surface of the back protective plate, and a mating slot fastener is fixedly installed on the bottom surface of the back protective plate. The bottom surface of the limiting top cover, located in the middle, is provided with an inner snap-fit ​​plate that is movably fitted onto the inner wall of the top of the side protection plate and the back protection plate. The top surface of the foundation plate, located at the four edges, is provided with a limiting rod. A docking slot buckle is fixedly installed on the bottom surface of the side protection plate, and the inner wall of the docking slot buckle is movably fitted onto the outer surface of the limiting rod. An L-shaped snap-fit ​​buckle is fixedly connected to one side surface of the side protection plate. L-shaped docking grooves are opened on both sides of the back protection plate, and the outer surface of the L-shaped snap-fit ​​buckle is movably fitted onto the inner wall of the L-shaped docking groove.

[0008] Preferably, the inner wall of the side protective plate is fixedly connected with an overlapping buckle, and the outer surface of the side protective plate is provided with a one-way ventilation groove.

[0009] Preferably, a closing door is sway-connected to one side surface of the side protective plate, and a motor is fixedly installed on the outer surface of the closing door.

[0010] Preferably, an arc-shaped locking strip is fixedly connected to the output end of the motor, and a sleeve lock is fixedly connected to the outer surface of the closed door. The outer surface of the arc-shaped locking strip is movably sleeved on the inner wall of the sleeve lock.

[0011] Preferably, a docking limiting groove is formed on the top surface of the side protective plate, and a docking limiting strip is fixedly connected to the bottom surface of the limiting top cover and at the two side edges, and the outer surface of the docking limiting strip is movably sleeved on the inner wall of the docking limiting groove.

[0012] Preferably, a raised moisture-proof groove is provided on the bottom surface of the foundation plate, and a limiting sliding groove is provided on the top surface of the foundation plate at the two side edges. Two snap-fit ​​pads are movably sleeved on the inner wall of the side protective plate at the outer surface of the overlapping buckle.

[0013] Preferably, a dust collection box is slidably fitted onto the top surface of the foundation platform and the inner wall of the limiting groove, and a blower is detachably installed on the top surface of one of the snap-fit ​​pads.

[0014] Preferably, an air guide pipe is fixedly connected to the inner wall of the back protective plate, the top end of the air guide pipe is movably sleeved on the inner wall of the output end of the blower, the other end of the air guide pipe is detachably installed on the inner wall of the dust collection box, and the outer surface of the air guide pipe is movably sleeved on the outer surface of the snap-fit ​​pad.

[0015] The beneficial effects of this invention are as follows: 1. The intelligent oil-immersed transformer protective cover of the present invention, when installing the foundation platform, the mating slots one and two on the bottom surfaces of the side protective plate and the back protective plate are respectively sleeved onto the surface of the limiting rod. The back protective plate is then erected, and the side protective plate is lifted and swung so that the inner wall surface of the side protective plate overlaps and adheres to the outer surface of the back protective plate. The L-shaped snap fasteners on the outer surface of the side protective plate are sleeved onto the inner wall surface of the L-shaped mating groove, thus limiting the position of the L-shaped mating groove. This design prevents the back panel from tilting and collapsing backward. Then, the limiting top cover is fitted onto the top surface of the side and back panels, and the inner snap-fit ​​plate is fitted onto the inner wall of the side and back panels. Finally, the inner wall of the limiting top cover is fitted onto the outer surface of the side and back panels. This design greatly prevents the side panels from tilting outward during later handling, achieving the effect of keeping the side and back panels in place by interlocking them without the need for screws. 2. The intelligent oil-immersed transformer protective cover of the present invention, when the limiting top cover overlaps the top surface of the side protective plate, the mating limiting strip on the inner wall of the limiting top cover is sleeved on the inner wall of the mating limiting groove, and then the mating limiting strip is snapped onto the inner wall of the mating limiting groove. The position of the mating limiting strip is limited by the mating limiting groove. The thickness of the inner snap-fit ​​plate makes the outer surface of the inner snap-fit ​​plate fit against the inner wall of the side protective plate, so that the distance and small gaps between the inner snap-fit ​​plate and the side protective plate and the back protective plate are limited in position. Through the tenon and mortise structure between the mating limiting strip and the inner snap-fit ​​plate and the side protective plate, the limiting top cover will not detach from the top surface of the side protective plate when the side protective plate is tilted, and the side protective plate and the limiting top cover will not wobble too much. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a perspective view of the present invention; Figure 2 This is a three-dimensional view of the foundation platform in this invention; Figure 3 This is a three-dimensional cross-sectional view of the foundation platform in this invention; Figure 4 This is a perspective view of the side protective plate in this invention. Figure 5 This is a perspective view of the unfolded back protective plate in this invention; Figure 6 This is a partial sectional perspective view of the foundation platform and side protection plate in this invention; Figure 7 This is a three-dimensional view of the arc-shaped snap-fit ​​strip in this invention; Figure 8 This is a perspective view of the limiting top cover in this invention. Figure 9 This is a three-dimensional view of the docking slot in this invention.

[0018] In the diagram: 11. Foundation platform; 111. Elevated moisture-proof groove; 112. Limiting slide; 113. Limiting rod; 114. Dust collection box; 115. Snap-fit ​​pad; 116. Blower; 12. Side protective plate; 121. Overlapping buckle; 122. Butt joint slot buckle one; 123. L-shaped snap-fit ​​buckle; 124. Butt joint limiting groove; 125. One-way ventilation groove; 126. Closed door; a1. Motor; a2. Arc-shaped snap-fit ​​strip; a3. Sleeve lock; 13. Rear protective plate; 131. Air duct; 132. L-shaped butt joint groove; 133. Butt joint slot buckle two; 14. Limiting top cover; 141. Inner snap-fit ​​plate; 142. Butt joint limiting strip; 15. Oil-immersed transformer. Detailed Implementation

[0019] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0020] like Figures 1 to 9As shown, an intelligent oil-immersed transformer protective cover according to an embodiment of the present invention includes a foundation plate 11 and side protective plates 12 movably sleeved on the top two edges of the foundation plate 11, a back protective plate 13 movably sleeved on the top surface of the foundation plate 11 and located at one edge, a limiting top cover 14 movably sleeved on the top outer surfaces of the side protective plates 12 and the back protective plate 13, an oil-immersed transformer 15 detachably installed on the inner wall of the side protective plate 12, one side surface of the side protective plate 12 movably sleeved on the outer surface of the back protective plate 13, and a bottom of the limiting top cover 14 with a docking slot 133 fixedly installed on the bottom surface of the back protective plate 13. An inner locking plate 141 is provided on the surface of the base plate 11 and located in the middle position, which is movably sleeved on the inner wall of the top of the side protection plate 12 and the back protection plate 13. A limit rod 113 is provided on the top surface of the base plate 11 and located at the four edges. A docking slot buckle 122 is fixedly installed on the bottom surface of the side protection plate 12. The inner wall of the docking slot buckle 122 is movably sleeved on the outer surface of the limit rod 113. An L-shaped locking buckle 123 is fixedly connected to one side surface of the side protection plate 12. L-shaped docking grooves 132 are opened on both sides of the back protection plate 13. The outer surface of the L-shaped locking buckle 123 is movably sleeved on the inner wall of the L-shaped docking groove 132.

[0021] When installing the foundation platform 11, the mating slots 122 and 133 on the bottom surfaces of the side protection plate 12 and the back protection plate 13 are respectively fitted onto the surface of the limiting rod 113. The back protection plate 13 is then erected, and the side protection plate 12 is lifted and swung so that the inner wall of the side protection plate 12 overlaps and adheres to the outer surface of the back protection plate 13. The L-shaped snap fasteners 123 on the outer surface of the side protection plate 12 are fitted onto the inner wall of the L-shaped mating groove 132, thus limiting the position of the L-shaped mating groove 132 and preventing the back protection plate 13 from tilting and collapsing backward. At this point, the limiting top cover 14 is then installed. The inner snap-fit ​​plate 141 is fitted onto the top surface of the side protective plate 12 and the back protective plate 13, and the inner snap-fit ​​plate 141 is fitted onto the inner wall surface of the side protective plate 12 and the back protective plate 13. Then, the inner wall surface of the limiting top cover 14 is fitted onto the outer surface of the side protective plate 12 and the back protective plate 13. This can greatly prevent the side protective plate 12 from bulging and tilting during later transportation. It achieves the effect of using mutual snap-fit ​​to limit the side protective plate 12 and the back protective plate 13 to their original position without the need for screws for fixing. This avoids the problem of screws wearing out after repeated disassembly when the protective cover is disassembled later, and the problem of the protective cover shaking when the screws are fixed after wear.

[0022] like Figures 1 to 2 , Figure 4 - Figure 6 and Figure 8 As shown, a docking limiting groove 124 is provided on the top surface of the side protective plate 12, and a docking limiting strip 142 is fixedly connected to the bottom surface of the limiting top cover 14 and located at the two side edges. The outer surface of the docking limiting strip 142 is movably sleeved on the inner wall of the docking limiting groove 124.

[0023] When the limiting top cover 14 overlaps the top surface of the side protective plate 12, the mating limiting strip 142 on the inner wall of the limiting top cover 14 is sleeved onto the inner wall of the mating limiting groove 124, and then the mating limiting strip 142 is snapped onto the inner wall of the mating limiting groove 124. The position of the mating limiting strip 142 is limited by the mating limiting groove 124, and the thickness of the inner retaining plate 141 is used to make the outer surface of the inner retaining plate 141 fit against the side protective plate 12. On the inner wall, the spacing and small gaps between the inner snap-fit ​​plate 141 and the side protection plate 12 and the back protection plate 13 are positioned. Through the tenon and mortise structure between the limiting strip 142 and the inner snap-fit ​​plate 141 and the side protection plate 12, the limiting top cover 14 will not detach from the top surface of the side protection plate 12 when the side protection plate 12 is tilted, and the side protection plate 12 and the limiting top cover 14 will not have too much shaking effect.

[0024] like Figure 2 , Figure 5 and Figure 7 As shown, an overlapping buckle 121 is fixedly connected to the inner wall of the side protective plate 12, and a one-way ventilation groove 125 is opened on the outer surface of the side protective plate 12. A closing door 126 is sway-connected to one side surface of the side protective plate 12. A motor a1 is fixedly installed on the outer surface of the closing door 126. An arc-shaped locking strip a2 is fixedly connected to the output end of the motor a1. A sleeve lock a3 is fixedly connected to the outer surface of the closing door 126. The outer surface of the arc-shaped locking strip a2 is movably sleeved on the inner wall of the sleeve lock a3.

[0025] After the side protective plate 12 and the back protective plate 13 are closed and fitted together, the oil-immersed transformer 15 is attached to the top surface of the snap-fit ​​pad 115, and the power receiving end of the motor a1 is connected to the surface of the oil-immersed transformer 15. If the surface of the oil-immersed transformer 15 leaks current, the connection line between the motor a1 and the oil-immersed transformer 15 will be energized. The energized motor a1 will rotate the arc-shaped snap-fit ​​strip a2. After the arc-shaped snap-fit ​​strip a2 rotates, it will slide into the inside of the snap-fit ​​lock a3. After the arc-shaped snap-fit ​​strips a2 on both sides snap together, the surface of the closed door 126 will be restricted. Later, employees can check whether the motor a1 on the surface of the closed door 126 is in a locked state to determine whether there is a leakage effect on the surface of the oil-immersed transformer 15 inside the foundation plate 11.

[0026] like Figures 1 to 7 As shown, a raised moisture-proof groove 111 is provided on the bottom surface of the foundation plate 11. A limiting groove 112 is provided on the top surface of the foundation plate 11 and at the two side edges. Two snap-fit ​​pads 115 are movably sleeved on the inner wall of the side protection plate 12 and on the outer surface of the overlapping buckle 121. A dust collection box 114 is slidably sleeved on the top surface of the foundation plate 11 and on the inner wall of the limiting groove 112. A blower 116 is detachably installed on the top surface of one snap-fit ​​pad 115. An air guide pipe 131 is fixedly connected to the inner wall of the back protection plate 13. The top end of the air guide pipe 131 is movably sleeved on the inner wall of the output end of the blower 116. The other end of the air guide pipe 131 is detachably installed on the inner wall of the dust collection box 114. The outer surface of the air guide pipe 131 is movably sleeved on the outer surface of the snap-fit ​​pad 115.

[0027] When the oil-immersed transformer 15 has been running for a long time, the heat generated on the surface of the oil-immersed transformer 15 will accumulate inside the side protection plate 12. At this time, the blower 116 absorbs the hot air accumulated on the inner wall of the top of the side protection plate 12, and the absorbed hot air is injected into the bottom edge of the snap-fit ​​pad 115 through the air guide pipe 131. The collected gas is filtered through the dust collection box 114, and the filtered gas is discharged through the one-way ventilation grooves 125 on both sides of the side protection plate 12, so that the inside of the side protection plate 12 is kept at a constant temperature. After the top surface of the side protection plate 12 and the back protection plate 13 is positioned by limiting the top cover 14, the snap-fit ​​pad 115 and the foundation plate 11 extend horizontally into the foundation plate 11. The snap-fit ​​buckle 121 on the inner wall of the side protection plate 12 overlaps with the bottom surfaces of both sides of the snap-fit ​​pad 115, thus positioning the snap-fit ​​pad 115. The barbs of the snap-fit ​​buckle 121 allow the snap-fit ​​pad 115 to be firmly positioned on the outer surface of the side protection plate 12. The two snap-fit ​​pads 115 can position the inner wall of the side protection plate 12.

[0028] Working principle: When installing the foundation plate 11, the mating slots 122 and 133 on the bottom surfaces of the side protection plate 12 and the back protection plate 13 are respectively fitted onto the surface of the limiting rod 113. The back protection plate 13 is then erected, and the side protection plate 12 is lifted and swung, causing the inner wall of the side protection plate 12 to overlap and adhere to the outer surface of the back protection plate 13. The L-shaped snap fasteners 123 on the outer surface of the side protection plate 12 are then fitted onto the inner wall of the L-shaped mating groove 132, thus limiting the position of the L-shaped mating groove 132. Since the back protective plate 13 cannot tilt and collapse backward, the limiting top cover 14 is then fitted onto the top surface of the side protective plate 12 and the back protective plate 13, and the inner snap-fit ​​plate 141 is fitted onto the inner wall surface of the side protective plate 12 and the back protective plate 13. The inner wall surface of the limiting top cover 14 is then fitted onto the outer surface of the side protective plate 12 and the back protective plate 13. This can greatly prevent the side protective plate 12 from tilting outward during the later handling process, and achieve the effect of limiting the side protective plate 12 and the back protective plate 13 to their original position by interlocking with each other, without the need to use screws for fixing. When the limiting top cover 14 overlaps the top surface of the side protective plate 12, the mating limiting strip 142 on the inner wall of the limiting top cover 14 is sleeved onto the inner wall of the mating limiting groove 124, and then the mating limiting strip 142 is snapped onto the inner wall of the mating limiting groove 124. The position of the mating limiting strip 142 is limited by the mating limiting groove 124, and the thickness of the inner retaining plate 141 is used to make the outer surface of the inner retaining plate 141 fit against the side protective plate 12. On the inner wall, the spacing and small gaps between the inner snap-fit ​​plate 141 and the side protection plate 12 and the back protection plate 13 are positioned. Through the tenon and mortise structure between the limiting strip 142 and the inner snap-fit ​​plate 141 and the side protection plate 12, the limiting top cover 14 will not detach from the top surface of the side protection plate 12 when the side protection plate 12 is tilted, and the side protection plate 12 and the limiting top cover 14 will not have too much shaking effect. After the side protective plate 12 and the back protective plate 13 are closed and fitted together, the oil-immersed transformer 15 is attached to the top surface of the snap-fit ​​pad 115, and the power receiving end of the motor a1 is connected to the surface of the oil-immersed transformer 15. If the surface of the oil-immersed transformer 15 leaks current, the connection line between the motor a1 and the oil-immersed transformer 15 will be energized. The energized motor a1 will rotate the arc-shaped snap-fit ​​strip a2. After the arc-shaped snap-fit ​​strip a2 rotates, it will slide into the inside of the snap-fit ​​lock a3. After the arc-shaped snap-fit ​​strips a2 on both sides snap together, the surface of the closed door 126 will be restricted. Later, employees can check whether the motor a1 on the surface of the closed door 126 is in a locked state to determine whether there is a leakage effect on the surface of the oil-immersed transformer 15 inside the foundation plate 11. After the oil-immersed transformer 15 has been running for a long time, the heat generated on the surface of the oil-immersed transformer 15 will accumulate inside the side protection plate 12. At this time, the blower 116 absorbs the hot air accumulated on the inner wall of the top of the side protection plate 12, and the absorbed hot air is injected into the bottom edge of the snap-fit ​​pad 115 through the air guide pipe 131. The collected gas is filtered through the dust collection box 114, and the filtered gas is discharged through the one-way ventilation grooves 125 on both sides of the side protection plate 12, so that the inside of the side protection plate 12 is kept at a constant temperature.

[0029] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An intelligent oil-immersed transformer protective cover, comprising a foundation plate (11) and side protective plates (12) movably sleeved on the top two edges of the foundation plate (11), a back protective plate (13) movably sleeved on the top surface of the foundation plate (11) and located on one side edge, a limiting top cover (14) movably sleeved on the top outer surfaces of the side protective plates (12) and the back protective plate (13), and an oil-immersed transformer (15) detachably installed on the inner wall of the side protective plates (12), characterized in that: One side surface of the side protective plate (12) is movably sleeved on the outer surface of the back protective plate (13). A docking slot buckle (133) is fixedly installed on the bottom surface of the back protective plate (13). An inner snap-fit ​​plate (141) is movably sleeved on the inner wall of the top of the side protective plate (12) and the back protective plate (13) at the middle position on the bottom surface of the limiting top cover (14). A limiting rod (113) is provided on the top surface of the foundation plate (11) at the four edges. A docking slot buckle (122) is fixedly installed on the bottom surface of the side protective plate (12). The inner wall of the docking slot buckle (122) is movably sleeved on the outer surface of the limiting rod (113). An L-shaped snap fastener (123) is fixedly connected to one side surface of the side protective plate (12). An L-shaped docking groove (132) is opened on both sides of the back protective plate (13). The outer surface of the L-shaped snap fastener (123) is movably sleeved on the inner wall of the L-shaped docking groove (132).

2. The intelligent oil-immersed transformer protective cover according to claim 1, characterized in that: The inner wall of the side protection plate (12) is fixedly connected with a snap fastener (121), and a one-way ventilation groove (125) is provided on the outer surface of the side protection plate (12).

3. The intelligent oil-immersed transformer protective cover according to claim 2, characterized in that: A closing door (126) is sway-connected to one side surface of the side protective plate (12), and a motor (a1) is fixedly installed on the outer surface of the closing door (126).

4. The intelligent oil-immersed transformer protective cover according to claim 3, characterized in that: An arc-shaped locking strip (a2) is fixedly connected to the output end of the motor (a1), and a sleeve lock (a3) ​​is fixedly connected to the outer surface of the closed door (126). The outer surface of the arc-shaped locking strip (a2) is movably sleeved on the inner wall of the sleeve lock (a3).

5. The intelligent oil-immersed transformer protective cover according to claim 4, characterized in that: The top surface of the side protective plate (12) is provided with a docking limiting groove (124), and the bottom surface of the limiting top cover (14) and the two side edges are fixedly connected with docking limiting strips (142). The outer surface of the docking limiting strips (142) is movably sleeved on the inner wall of the docking limiting groove (124).

6. The intelligent oil-immersed transformer protective cover according to claim 1, characterized in that: The bottom surface of the foundation plate (11) is provided with a raised moisture-proof groove (111), the top surface of the foundation plate (11) and the two side edges are provided with a limiting groove (112), and two snap-fit ​​pads (115) are movably sleeved on the inner wall surface of the side protection plate (12) and the outer surface of the overlapping buckle (121).

7. The intelligent oil-immersed transformer protective cover according to claim 6, characterized in that: A dust collection box (114) is slidably sleeved on the top surface of the foundation plate (11) and on the inner wall of the limiting groove (112), and a blower (116) is detachably installed on the top surface of a snap-fit ​​pad (115).

8. The intelligent oil-immersed transformer protective cover according to claim 1, characterized in that: An air guide pipe (131) is fixedly connected to the inner wall of the back protective plate (13). The top end of the air guide pipe (131) is movably sleeved on the inner wall of the output end of the blower (116). The other end of the air guide pipe (131) is detachably installed on the inner wall of the dust collection box (114). The outer surface of the air guide pipe (131) is movably sleeved on the outer surface of the snap-fit ​​pad (115).

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