阅读说明：本技术 一种低风噪汽车后视镜 (Low wind noise automobile rearview mirror ) 是由 张凯歌 陈世荣 张庆军 于 2021-08-24 设计创作，主要内容包括：本发明公开了一种低风噪汽车后视镜,包括后视镜壳体和设置在后视镜壳体上的后视镜片,后视镜壳体上设置有导水槽,导水槽中设置有降噪结构。本发明中,通过在导水槽中设置降噪结构,降噪结构能够有效降低气流在经过导水槽时产生的风噪,从而不易被乘客觉察到,提高乘客的乘车体验。(The invention discloses a low-wind-noise automobile rearview mirror which comprises a rearview mirror shell and a rearview mirror arranged on the rearview mirror shell, wherein a water chute is formed in the rearview mirror shell, and a noise reduction structure is arranged in the water chute. According to the invention, the noise reduction structure is arranged in the water chute, so that the noise reduction structure can effectively reduce wind noise generated when air flow passes through the water chute, and therefore, the air flow is not easy to be perceived by passengers, and the riding experience of the passengers is improved.)

1. The utility model provides a low wind noise automobile rearview mirror, includes rear-view mirror housing and sets up the back vision lens on the rear-view mirror housing, is provided with guiding gutter, its characterized in that on the rear-view mirror housing: a noise reduction structure is arranged in the water chute.

2. The rearview mirror of claim 1, wherein the noise reduction structure is a spoiler, the spoiler is disposed along the length direction of the guide groove, and the middle portion of the spoiler is protruded upward.

3. The low wind noise automobile rearview mirror of claim 1, wherein the noise reduction structure is a buffer sheet arranged on the rear wall of the water chute, the buffer sheet is arranged along the length direction of the water chute, and an included angle is formed between the buffer sheet and the rear wall of the water chute.

4. The low wind noise automobile rearview mirror of claim 1, wherein the noise reduction structure is a fillet arranged along the length direction of the diversion trench, and the cross section of the fillet is in the shape of a circular arc which is concave downwards.

5. The automobile rearview mirror with low wind noise as claimed in claim 1, wherein the rearview mirror is provided with a mounting hole, the back surface of the rearview mirror is provided with a fixed cylinder corresponding to the mounting hole, the bottom of the fixed cylinder is provided with an elastic moving part, the elastic moving part is connected with a movable lens, and the movable lens is matched with the mounting hole in shape; the rearview mirror is detachably connected with a wide-angle lens, the wide-angle lens comprises a convex lens shell and a convex lens connected to the front side of the convex lens shell, the back side of the convex lens shell is provided with an insertion part matched with the fixed cylinder, the insertion part is provided with a piston cylinder, one end of the piston cylinder is provided with an end plate, a piston is arranged in the piston cylinder, a piston cavity is formed between the piston and the end plate, and a second spring is arranged in front of the piston and the other end of the piston cylinder; the piston is connected with a piston rod, the end plate is provided with a shaft hole corresponding to the piston rod, and the piston rod penetrates through the shaft hole; the front end of the piston rod is provided with an inclined plane, and the inner wall of the fixed cylinder is provided with a clamping groove matched with the piston rod; an annular groove is formed in the back face of the convex mirror shell, a liquid filling ring is arranged in the annular groove, an annular liquid filling cavity is formed in the liquid filling ring, a connecting pipe is arranged between the liquid filling ring and the piston cylinder and used for communicating the piston cavity with the annular liquid filling cavity, and liquid media are filled in the piston cavity and the annular liquid filling cavity; a liquid flow rate regulator is arranged on the connecting pipe, the liquid flow rate regulator comprises a shell and a partition plate arranged in the shell, and the partition plate divides the shell into a first cavity and a second cavity; the connecting pipe is disconnected at the shell and is divided into a first pipe body and a second pipe body; one end of the first pipe body is connected with one end, close to the first cavity, of the shell, and the other end of the first pipe body is connected with the liquid filling ring; one end of the second pipe body is connected with one end, close to the second cavity, of the shell, and the other end of the second pipe body is connected with the piston cavity; the baffle is provided with a first through hole and a second through hole, the diameter of the second through hole is larger than that of the first through hole, one end, close to the second cavity, of the second through hole is provided with a valve ball, the inner wall of the shell is provided with an elastic pressing sheet, and the valve ball is pressed at one end of the second through hole by the elastic pressing sheet.

6. A low wind noise automotive rearview mirror according to claim 5, wherein a rubber pad is provided on an end of said insertion portion remote from said mirror housing.

7. The low wind noise automobile rearview mirror as claimed in claim 5, wherein the elastic moving part comprises a guide cylinder fixed at the bottom of the fixed cylinder and a moving block slidably connected in the guide cylinder, a first spring is arranged between one end of the guide cylinder and the moving block, a guide hole is arranged at the other end of the guide cylinder, a telescopic rod is arranged on the moving block, and the telescopic rod passes through the guide hole and is connected with the moving lens.

8. A low wind noise automotive rearview mirror according to claim 5, wherein said liquid-filled ring is made of rubber.

Technical Field

The invention relates to the technical field of automobiles, in particular to a low-wind-noise automobile rearview mirror.

Background

The rearview mirror is a component arranged on two sides of the automobile and is used for helping a driver to observe the situation behind the automobile. As shown in the attached drawing 1, the existing automobile rearview mirror comprises a rearview mirror shell 1 and a rearview mirror blade 2 arranged on the rearview mirror shell 1, a water chute 3 is arranged on the rearview mirror shell, the water chute 3 is arranged on the outer surface of the rearview mirror shell, the cross section of the water chute is rectangular, the water chute can guide rainwater flowing through the rearview mirror to the two sides of the rearview mirror instead of crossing a mirror frame base and then hitting the mirror surface of the rearview mirror, the view field of the rearview mirror is guaranteed, and the driving safety of customers is further guaranteed.

When the automobile runs at a high speed, airflow flows through a water chute on the rearview mirror shell, certain wind noise is generated, and the generation principle of the wind noise is shown in the attached drawing 2: the incoming flow boundary layer 6 is separated at the front wall 4 of the water chute to form a shear layer 7, unstable waves in the shear layer 7 develop along with the flow direction downstream, then the shear layer 7 collides with the rear wall 5 of the water chute to generate disturbance waves, the disturbance waves are reflected by the rear wall of the water chute and then are transmitted back to the flow separation region at the front edge of the water chute in the form of sound waves to form a feedback loop 8, and meanwhile, stable turbulence can be generated in the water chute, so that wind noise of the rearview mirror is formed. The wind noise is similar to a whistle sound, is a very obvious single-frequency sound, has very high amplitude of about 20dB, is very easy to be perceived by passengers, and seriously influences the riding experience of the passengers.

Disclosure of Invention

The invention aims to solve the problems that the existing automobile rearview mirror is provided with a water chute, and when an automobile runs at a high speed, airflow flows through the water chute, obvious wind noise is generated, is easily perceived by passengers, and seriously influences the riding experience of the passengers.

The purpose of the invention is realized by the following technical scheme: the utility model provides a low wind makes an uproar automobile rearview mirror, includes rear-view mirror housing and sets up the back vision lens on the rear-view mirror housing, is provided with the guiding gutter on the rear-view mirror housing, is provided with in the guiding gutter to fall the structure of making an uproar.

According to the invention, the noise reduction structure is arranged in the water chute, so that the noise reduction structure can effectively reduce wind noise generated when air flow passes through the water chute, and therefore, the air flow is not easy to be perceived by passengers, and the riding experience of the passengers is improved.

Preferably, the noise reduction structure is a spoiler, the spoiler is arranged along the length direction of the flow guide groove, and the middle part of the spoiler protrudes upwards. Under the action of the spoiler, stable turbulence cannot be formed in the diversion trench, namely, the airflow cannot firstly impact the rear wall of the diversion trench and then impact the front wall of the diversion trench, the airflow exchange process is disturbed, and further the flow of the shear layer is thoroughly disturbed, and stable whistle frequency cannot be formed, so that the formation of wind noise is inhibited.

Preferably, the noise reduction structure is a buffer sheet arranged on the rear wall of the water guide groove, the buffer sheet is arranged along the length direction of the water guide groove, and an included angle is formed between the buffer sheet and the rear wall of the water guide groove. The buffer sheet is made of materials such as high-density sponge and rubber and has the functions of buffering and energy absorption, when the shear layer impacts the buffer sheet, the buffer sheet can absorb certain energy, the energy of a feedback loop is reduced, and therefore wind noise is reduced.

Preferably, the noise reduction structure is a fillet arranged along the length direction of the diversion trench, and the cross section of the fillet is in the shape of a circular arc which is concave downwards. The fairing is in a smooth arc shape, so that the appearance of fluid in the guide groove is improved, turbulence is not easily generated in the guide groove, and wind noise is effectively reduced.

Preferably, the rearview mirror is provided with a mounting hole, the back of the rearview mirror is provided with a fixed cylinder corresponding to the mounting hole, the bottom of the fixed cylinder is provided with an elastic moving part, the elastic moving part is connected with a movable lens, and the movable lens is matched with the mounting hole in shape; the rearview mirror is detachably connected with a wide-angle lens, the wide-angle lens comprises a convex lens shell and a convex lens connected to the front side of the convex lens shell, the back side of the convex lens shell is provided with an insertion part matched with the fixed cylinder, the insertion part is provided with a piston cylinder, one end of the piston cylinder is provided with an end plate, a piston is arranged in the piston cylinder, a piston cavity is formed between the piston and the end plate, and a second spring is arranged in front of the piston and the other end of the piston cylinder; the piston is connected with a piston rod, the end plate is provided with a shaft hole corresponding to the piston rod, and the piston rod penetrates through the shaft hole; the front end of the piston rod is provided with an inclined plane, and the inner wall of the fixed cylinder is provided with a clamping groove matched with the piston rod; an annular groove is formed in the back face of the convex mirror shell, a liquid filling ring is arranged in the annular groove, an annular liquid filling cavity is formed in the liquid filling ring, a connecting pipe is arranged between the liquid filling ring and the piston cylinder and used for communicating the piston cavity with the annular liquid filling cavity, and liquid media are filled in the piston cavity and the annular liquid filling cavity; a liquid flow rate regulator is arranged on the connecting pipe, the liquid flow rate regulator comprises a shell and a partition plate arranged in the shell, and the partition plate divides the shell into a first cavity and a second cavity; the connecting pipe is disconnected at the shell and is divided into a first pipe body and a second pipe body; one end of the first pipe body is connected with one end, close to the first cavity, of the shell, and the other end of the first pipe body is connected with the liquid filling ring; one end of the second pipe body is connected with one end, close to the second cavity, of the shell, and the other end of the second pipe body is connected with the piston cavity; the baffle is provided with a first through hole and a second through hole, the diameter of the second through hole is larger than that of the first through hole, one end, close to the second cavity, of the second through hole is provided with a valve ball, the inner wall of the shell is provided with an elastic pressing sheet, and the valve ball is pressed at one end of the second through hole by the elastic pressing sheet. In order to enlarge the observation range of the rearview mirror, a driver usually installs a wide-angle mirror on the rearview mirror, the wide-angle mirror is usually directly adhered to the mirror surface of the rearview mirror through a double-sided adhesive tape, the installation mode is inconvenient to detach and unreliable in installation, and the wide-angle mirror is easy to age to fall off from the rearview mirror due to the fact that the double-sided adhesive tape is used for a long time. The novel mounting structure is adopted, and the novel mounting structure has the advantages of being reliable in mounting and convenient to detach. The connecting pipe is used for communicating the piston cavity with the annular liquid filling cavity in the liquid filling ring, so that the liquid medium in the liquid filling ring can flow into the piston cavity through the connecting pipe, and meanwhile, the liquid medium in the piston cavity can also flow into the liquid filling ring through the connecting pipe; when the liquid medium in the liquid filling ring flows into the piston cavity through the connecting pipe, the liquid medium flows from the first cavity to the second cavity in the liquid flow rate regulator, the valve ball on the second through hole is flushed away by the liquid medium, and the first through hole and the second through hole are both in a conducting state, so that the liquid medium can flow through the liquid flow rate regulator at a higher flow rate; on the contrary, when the liquid medium in the piston cavity flows into the liquid filling cavity through the connecting pipe, the liquid medium flows from the second cavity to the first cavity in the liquid flow rate regulator, the second through hole is in a closed state, the liquid medium can only pass through the first through hole, and the liquid medium can only pass through the liquid flow rate regulator at a slower flow rate. When the wide-angle lens is not installed on the rearview mirror, the elastic moving part pushes the movable lens out to the position of the installation hole, so that the movable lens is just filled in the installation hole, and a complete rearview mirror is formed; when the wide-angle lens is installed, the inserting part on the wide-angle lens is only required to be aligned to the position of the installing hole and inserted into the fixed cylinder, at the moment, the movable lens is pushed into the fixed cylinder by the inserting part, and meanwhile, when the inserting part is inserted to a certain depth, the front end of the piston rod is clamped into the clamping groove, so that the wide-angle lens is fixedly installed on the rearview mirror; the liquid filling ring is made of rubber, is made of soft materials, is filled with liquid media, and can serve as a buffer part between the convex lens shell and the rearview mirror, so that the impact between the wide-angle lens and the rearview mirror can be reduced, and the rear-view mirror is prevented from being cracked; when the wide-angle lens needs to be detached, the convex lens shell is only required to be pressed towards one side of the rearview mirror, at the moment, the liquid filling ring is extruded, part of liquid medium in the liquid filling ring flows into the piston cavity through the connecting pipe at a high flow rate, the piston and the piston rod are pushed to move, the front end of the piston rod is separated from the clamping groove, and then the insertion part on the wide-angle lens is pulled out of the fixed cylinder; in the process of pulling out the insertion part on the wide-angle lens from the fixed cylinder, the liquid medium in the piston cavity flows back to the liquid filling ring through the connecting pipe, but in the flowing direction, the liquid medium can only pass through the liquid flow rate regulator at a slow flow rate, so that the liquid medium in the piston cavity can only flow back to the liquid filling ring at a slow speed, the telescopic rod extends out at a slow speed, the telescopic rod is ensured not to be clamped into the clamping groove again in the process of pulling out the insertion part from the fixed cylinder, and the wide-angle lens can be smoothly taken down.

Preferably, a rubber pad is arranged at one end of the insertion part far away from the convex mirror shell.

Preferably, the elastic moving part comprises a guide cylinder fixed at the bottom of the fixed cylinder and a moving block slidably connected in the guide cylinder, a first spring is arranged between one end of the guide cylinder and the moving block, a guide hole is formed in the other end of the guide cylinder, a telescopic rod is arranged on the moving block, and the telescopic rod penetrates through the guide hole and is connected with the movable lens.

Preferably, the liquid-filled ring is made of rubber.

The invention has the beneficial effects that: according to the invention, the noise reduction structure is arranged in the water chute, so that the noise reduction structure can effectively reduce wind noise generated when air flow passes through the water chute, and therefore, the air flow is not easy to be perceived by passengers, and the riding experience of the passengers is improved.

Drawings

Fig. 1 is a schematic structural view of a conventional automobile rearview mirror.

Fig. 2 is a schematic diagram of wind noise generation.

Fig. 3 is a schematic structural view of an automobile rearview mirror in embodiment 1 of the present invention.

Fig. 4 is an enlarged view of the middle of fig. 3.

Fig. 5 is a schematic view of a noise reduction structure in embodiment 2 of the present invention.

Fig. 6 is a schematic view of a noise reduction structure in embodiment 3 of the present invention.

Fig. 7 is an enlarged view of a portion B in fig. 3.

Fig. 8 is an enlarged view of the portion C in fig. 7.

Fig. 9 is an enlarged view of a portion D in fig. 7.

In the figure: 1. the rear view mirror comprises a rearview mirror shell, 2, a rearview mirror, 3, a water chute, 4, a water chute front wall, 5, a water chute rear wall, 6, an incoming flow boundary layer, 7, a shear layer, 8, a feedback loop, 9, a spoiler, 10, a buffer sheet, 11, a rectifying plate, 12, a fixed cylinder, 13, a movable mirror, 14, a guide cylinder, 15, a movable block, 16, a first spring, 17, a telescopic rod, 18, a convex mirror shell, 19, a convex mirror, 20, an insertion part, 21, a rubber pad, 22, a liquid filling ring, 23, a connecting pipe, 24, a clamping groove, 25, a piston cylinder, 26, a piston, 27, a second spring, 28, an end plate, 29, a piston rod, 30, a piston cavity, 31, a shell, 32, a partition plate, 33, a first cavity, 34, a second cavity, 35, a first through hole, 36, a second through hole, 37, a valve ball, 38 and an elastic pressing sheet.

Detailed Description

The invention is further described by the following detailed description in conjunction with the accompanying drawings.

Example 1:

as shown in fig. 3, 4, 7, 8 and 9, the low wind noise automobile rearview mirror comprises a rearview mirror housing 1 and a rearview mirror 2 arranged on the rearview mirror housing 1, wherein a water chute 3 is arranged on the rearview mirror housing 1, and the cross section of the water chute 3 is rectangular. A noise reduction structure is arranged in the water chute 3. In this embodiment, the noise reduction structure is a spoiler 9, the spoiler 9 is disposed along the length direction of the flow guide groove 3, and the middle portion of the spoiler 9 protrudes upward. Under the action of the spoiler, stable turbulence cannot be formed in the diversion trench, namely, the airflow cannot firstly impact the rear wall of the diversion trench and then impact the front wall of the diversion trench, the airflow exchange process is disturbed, and further the flow of the shear layer is thoroughly disturbed, and stable whistle frequency cannot be formed, so that the formation of wind noise is inhibited.

The rearview mirror 2 is provided with a mounting hole, the back of the rearview mirror 2 is provided with a fixed cylinder 12 corresponding to the mounting hole, and the fixed cylinder 12 is of a cylindrical structure. The bottom of the fixed cylinder 12 is provided with an elastic moving part. The elastic moving part comprises a guide cylinder 14 fixed at the bottom of the fixed cylinder 12 and a moving block 15 connected in the guide cylinder 14 in a sliding manner, a first spring 16 is arranged between one end of the guide cylinder 14 and the moving block 15, a guide hole is formed in the other end of the guide cylinder 14, an expansion link 17 is arranged on the moving block 15, and the expansion link 17 penetrates through the guide hole. The front end of the telescopic rod 17 is connected with a movable lens 13. The movable lens 13 is matched with the shape of the mounting hole. The movable lens 13 is movable in the fixed cylinder.

The rearview mirror 2 is detachably connected with a wide-angle lens, the wide-angle lens comprises a convex lens shell 18 and a convex lens 19 connected to the front side of the convex lens shell 18, and the back side of the convex lens shell 18 is provided with an insertion part 20 matched with the fixed cylinder 12. A rubber pad 21 is provided on the end of the insert 20 remote from the lenticular housing 18. The insertion portion 20 is provided with a piston cylinder 25. An end plate 28 is provided at one end of the piston cylinder 25, a piston 26 is provided in the piston cylinder 25, and a piston chamber 30 is formed between the piston 26 and the end plate 28. The piston 26 and the other end of the piston cylinder 25 are provided with a second spring 27 in front. A piston rod 29 is connected to the piston 26, and a shaft hole corresponding to the piston rod 29 is provided in the end plate 28, through which the piston rod 29 passes. The front end of the piston rod 29 is provided with a bevel. The inner wall of the fixed cylinder 12 is provided with a clamping groove 24 matched with the piston rod 29. An annular groove is arranged on the back surface of the convex mirror shell 18, a liquid filling ring 22 is arranged in the annular groove, and an annular liquid filling cavity is arranged in the liquid filling ring 22. The liquid-filled ring 22 is made of rubber. A connecting pipe 23 is arranged between the liquid filling ring 22 and the piston cylinder 25, and the connecting pipe 23 is used for communicating the piston cavity 30 with the annular liquid filling cavity. Both the piston chamber 30 and the annular charging chamber contain a liquid medium. The liquid medium is hydraulic oil.

The connection pipe 23 is provided with a liquid flow rate regulator. The liquid flow rate regulator includes a housing 31 and a partition 32 provided in the housing 31, the partition 32 dividing the interior of the housing 31 into a first chamber 33 and a second chamber 34. The connection pipe 23 is broken at the housing 31 and divided into a first pipe body and a second pipe body. One end of the first tube is connected to the end of the housing 31 adjacent the first chamber and the other end is connected to the liquid-filled ring 22. One end of the second tube is connected to the housing 31 at the end adjacent the second chamber and the other end is connected to the piston chamber 30. The partition 32 is provided with a first through hole 35 and a second through hole 36, and the diameter of the second through hole 36 is larger than that of the first through hole 35. A valve ball 37 is disposed at one end of the second through hole 36 close to the second chamber 34, and an elastic pressing piece 38 is disposed on the inner wall of the housing 31, and the valve ball 37 is pressed against one end of the second through hole 36 by the elastic pressing piece 38. The elastic pressing piece 38 is made of metal.

In order to enlarge the observation range of the rearview mirror, a driver usually installs a wide-angle mirror on the rearview mirror, the wide-angle mirror is usually directly adhered to the mirror surface of the rearview mirror through a double-sided adhesive tape, the installation mode is inconvenient to detach and unreliable in installation, and the wide-angle mirror is easy to age to fall off from the rearview mirror due to the fact that the double-sided adhesive tape is used for a long time. The novel mounting structure is adopted, and the novel mounting structure has the advantages of being reliable in mounting and convenient to detach. The connecting pipe is used for communicating the piston cavity with the annular liquid filling cavity in the liquid filling ring, so that the liquid medium in the liquid filling ring can flow into the piston cavity through the connecting pipe, and meanwhile, the liquid medium in the piston cavity can also flow into the liquid filling ring through the connecting pipe; when the liquid medium in the liquid filling ring flows into the piston cavity through the connecting pipe, the liquid medium flows from the first cavity to the second cavity in the liquid flow rate regulator, the valve ball on the second through hole is flushed away by the liquid medium, and the first through hole and the second through hole are both in a conducting state, so that the liquid medium can flow through the liquid flow rate regulator at a higher flow rate; on the contrary, when the liquid medium in the piston cavity flows into the liquid filling cavity through the connecting pipe, the liquid medium flows from the second cavity to the first cavity in the liquid flow rate regulator, the second through hole is in a closed state, the liquid medium can only pass through the first through hole, and the liquid medium can only pass through the liquid flow rate regulator at a slower flow rate. When the wide-angle lens is not installed on the rearview mirror, the elastic moving part pushes the movable lens out to the position of the installation hole, so that the movable lens is just filled in the installation hole, and a complete rearview mirror is formed; when the wide-angle lens is installed, the inserting part on the wide-angle lens is only required to be aligned to the position of the installing hole and inserted into the fixed cylinder, at the moment, the movable lens is pushed into the fixed cylinder by the inserting part, and meanwhile, when the inserting part is inserted to a certain depth, the front end of the piston rod is clamped into the clamping groove, so that the wide-angle lens is fixedly installed on the rearview mirror; the liquid filling ring is made of rubber, is made of soft materials, is filled with liquid media, and can serve as a buffer part between the convex lens shell and the rearview mirror, so that the impact between the wide-angle lens and the rearview mirror can be reduced, and the rear-view mirror is prevented from being cracked; when the wide-angle lens needs to be detached, the convex lens shell is only required to be pressed towards one side of the rearview mirror, at the moment, the liquid filling ring is extruded, part of liquid medium in the liquid filling ring flows into the piston cavity through the connecting pipe at a high flow rate, the piston and the piston rod are pushed to move, the front end of the piston rod is separated from the clamping groove, and then the insertion part on the wide-angle lens is pulled out of the fixed cylinder; in the process of pulling out the insertion part on the wide-angle lens from the fixed cylinder, the liquid medium in the piston cavity flows back to the liquid filling ring through the connecting pipe, but in the flowing direction, the liquid medium can only pass through the liquid flow rate regulator at a slow flow rate, so that the liquid medium in the piston cavity can only flow back to the liquid filling ring at a slow speed, the telescopic rod extends out at a slow speed, the telescopic rod is ensured not to be clamped into the clamping groove again in the process of pulling out the insertion part from the fixed cylinder, and the wide-angle lens can be smoothly taken down.

Example 2:

as shown in fig. 5, embodiment 2 differs from embodiment 1 in that: in embodiment 2, the noise reduction structure is a buffer sheet 10 disposed on the rear wall of the water chute, the buffer sheet 10 is disposed along the length direction of the water chute, and an included angle is formed between the buffer sheet 10 and the rear wall of the water chute. The buffer sheet is made of materials such as high-density sponge and rubber and has the functions of buffering and energy absorption, when the shear layer impacts the buffer sheet, the buffer sheet can absorb certain energy, the energy of a feedback loop is reduced, and therefore wind noise is reduced. The rest of the structure of example 2 is the same as example 1.

Example 3:

as shown in fig. 6, embodiment 3 differs from embodiment 1 in that: in embodiment 3, the noise reduction structure is a fillet 11 disposed along the length direction of the guiding groove, and the cross section of the fillet 11 is a circular arc shape recessed downward. The fairing is in a smooth arc shape, so that the appearance of fluid in the guide groove is improved, turbulence is not easily generated in the guide groove, and wind noise is effectively reduced. The rest of the structure of example 3 is the same as example 1.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.