Fan mounting structure, range hood and control method of range hood

Abstract

The invention discloses a fan mounting structure, a range hood and a control method of the range hood, belongs to the technical field of kitchen appliances, and is designed for solving the problems of high noise and the like of the range hood. The draught fan mounting structure comprises a draught fan assembly and a mounting assembly, wherein the draught fan assembly comprises a machine box and a draught fan arranged in the machine box; and the noise elimination assembly comprises a noise elimination box body communicated with the case, and the length of the noise elimination box body can be increased or reduced according to the rotating speed of the fan in the airflow direction so as to reduce airflow noise. According to the draught fan mounting structure, the range hood and the control method of the range hood, the length of the silencing box body can be adjusted according to the rotating speed of the draught fan, so that airflow noise is reduced, and the use experience is better; the silencing box body prolongs the distance from the case to the connecting pipe, and the noise transmitted to the smoke suction cavity is further weakened by using a method of increasing the spatial distance.

Description

Technical Field

[0001] The present invention relates to the technical field of kitchen appliances, and in particular to a fan installation structure, a range hood and a control method thereof. Background Art

[0002] A range hood is an electrical appliance used to collect and discharge indoor oil fumes. Its main working principle is to use a fan to form negative pressure in the smoke collecting chamber and the smoke collecting duct. Under the action of negative pressure, the indoor oil fumes enter the smoke collecting chamber and the smoke collecting duct, thereby completing the collection and discharge of oil fumes.

[0003] The fan generates noise when it is working, which leads to a poor user experience. To solve this problem, a split range hood is currently available that installs the fan in the ceiling. The smoke collecting chamber near the stove is connected to the fan through a smoke collecting pipe, and the ceiling is used to shield the fan to reduce noise. The fan is located at a higher position and is far away from the user, and the spatial distance is used to reduce noise to a certain extent.

[0004] The defects of existing split-type range hoods include: the suspended ceiling can only weaken the transmission of noise but cannot really reduce the noise; the noise generated by the fan can be transmitted to the smoke collecting chamber through the smoke collecting duct, and the user experience needs to be improved. Summary of the invention

[0005] The purpose of the present invention is to provide a fan installation structure, a range hood and a control method thereof, which solve the problem of high noise of the range hood and provide a good user experience.

[0006] To achieve this object, on the one hand, the present invention adopts the following technical solutions:

[0007] The fan installation structure includes: a fan assembly, including a chassis and a fan arranged in the chassis; and a silencer assembly, including a silencer box connected to the chassis, wherein the length of the silencer box can be increased or decreased along the airflow direction according to the rotation speed of the fan to reduce the airflow noise.

[0008] In one of the preferred embodiments, the fan mounting structure also includes a driving member, a lead screw and a slider with a built-in threaded hole, one end of the lead screw is connected to the rotation output end of the driving member, the other end of the lead screw is inserted into the threaded hole, and the slider can move along the axial direction of the lead screw when the lead screw rotates around its own axis; the chassis is sleeved on the air outlet end of the silencer box, one of the driving member and the slider is arranged in the chassis, and the other of the driving member and the slider is arranged in the silencer box, and the rotation of the lead screw can drive the chassis and the silencer box to slide relative to each other through the slider.

[0009] In one of the preferred embodiments, the fan mounting structure further includes a hanging plate, the hanging plate includes a chassis mounting portion and a muffler box mounting portion, the chassis is connected to the chassis mounting portion, and the muffler box body is fixedly connected to the muffler box mounting portion.

[0010] In one of the preferred embodiments, a plate hanging slide is disposed on the chassis mounting portion, a chassis plate hanging slide that matches the plate hanging slide is disposed on the chassis, and the chassis is slidably connected to the chassis mounting portion.

[0011] In one of the preferred embodiments, the silencer box body is a hollow structure, a silencer box air outlet is formed toward one end of the chassis, a silencer box sliding piece is provided on the silencer box body, a chassis silencer box sliding piece matching with the silencer box sliding piece is provided on the chassis, and the chassis can slide along the silencer box sliding piece to increase or reduce the length of the silencer box body.

[0012] In one of the preferred embodiments, two air inlets are provided on the muffler box, and the airflow can reach the fan after entering the muffler box from any of the air inlets.

[0013] In one of the preferred embodiments, a telescopic wall is provided on the chassis, a movable end of the telescopic wall is fixedly connected to the side wall of the chassis, and a fixed end of the telescopic wall is fixedly connected to the silencer box. When the chassis moves relative to the silencer box, the telescopic wall never blocks the air inlet.

[0014] In one of the preferred embodiments, a housing cavity is provided on the chassis, and the side edge of the telescopic wall is embedded in the housing cavity. When the chassis moves relative to the muffler box, the side edge of the telescopic wall moves in the housing cavity.

[0015] On the other hand, the present invention adopts the following technical solutions:

[0016] The range hood includes a smoke extraction chamber and a connecting pipe. The range hood also includes the above-mentioned fan installation structure. One end of the connecting pipe is connected to the smoke extraction chamber, and the other end of the connecting pipe is connected to the silencer box. The airflow can pass through the smoke extraction chamber, the connecting pipe and the silencer box in sequence and then reach the fan located in the chassis.

[0017] On the other hand, the present invention adopts the following technical solution:

[0018] A range hood control method, comprising:

[0019] Measure and record the noise spectrum F of the fan at different air volumes and the speed n of the fan impeller, and determine the spectrum segment F1-F2 that needs to be reduced at the speed n based on the noise spectrum F;

[0020] The length L of the silencer box along the airflow direction is calculated by the transmission loss formula, and the length L is matched with the speed n to form an nL table;

[0021] Start the range hood, determine the current length of the silencer box along the airflow direction and the speed n1 of the fan impeller, query the length L1 corresponding to the speed n1 through the nL table, and increase or decrease the length of the silencer box to L1.

[0022] The fan installation structure disclosed in the present invention includes a fan assembly and a silencer assembly, and the length of the silencer box can be adjusted according to the fan speed to reduce airflow noise and provide a better user experience; the silencer box extends the distance from the chassis to the connecting pipe, and uses the method of increasing the spatial distance to further weaken the noise transmitted to the smoking chamber.

[0023] The range hood disclosed in the present invention also includes the above-mentioned fan installation structure, and the airflow noise is reduced by adjusting the length of the silencer box, thereby providing a better user experience.

[0024] The range hood control method disclosed in the present invention can obtain the target length L1 according to the correspondence between the length L of the silencer box along the airflow direction and the rotation speed n of the fan impeller. The noise in the target frequency band can be eliminated by adjusting the length of the silencer box, and the user experience is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a structural schematic diagram of a range hood provided by a specific embodiment of the present invention;

[0026] Figure 2 It is a structural schematic diagram of a hanging plate provided in a specific embodiment of the present invention;

[0027] Figure 3 It is a schematic diagram of the combined structure of the muffler box, the driving member and the lead screw provided in a specific embodiment of the present invention;

[0028] Figure 4 It is a structural schematic diagram of a sound-absorbing box provided in a specific embodiment of the present invention;

[0029] Figure 5 It is a schematic diagram of the combined structure of a chassis, a fan and a slider provided in a specific embodiment of the present invention;

[0030] Figure 6 It is a schematic diagram of the initial position of the chassis moving relative to the muffler box provided by a specific embodiment of the present invention;

[0031] Figure 7 It is a schematic diagram of the terminal position of the movement of the chassis relative to the muffler box provided in a specific embodiment of the present invention.

[0032] In the figure:

[0033] 1. Chassis; 2. Fan; 3. Silencer box; 4. Driving part; 5. Lead screw; 6. Slider; 7. Hanging plate; 8. Smoking chamber; 9. Connecting pipe; 11. Chassis hanging plate sliding part; 12. Chassis silencer box sliding part; 13. Telescopic wall; 14. Accommodating chamber; 31. Air inlet; 32. Silencer box air outlet; 33. Silencer box sliding part; 61. Threaded hole; 71. Chassis mounting part; 72. Silencer box mounting part; 73. Hanging plate sliding part; 131. Moving end; 132. Fixed end. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0039] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0040] This embodiment discloses a fan installation structure and a range hood including the fan installation structure. Figures 1 to 5 As shown, the range hood further includes a smoke chamber 8 and a connecting pipe 9, and the fan installation structure includes a fan assembly and a muffler assembly. The fan assembly includes a chassis 1 and a fan 2 arranged in the chassis 1. Specifically, the chassis 1 is arranged between the ceiling and the roof of the house, and the fan 2 is arranged on the upper side of the chassis 1 with the air inlet facing downward; the muffler assembly includes a muffler box body 3 connected to the chassis 1.

[0041] One end of the connecting pipe 9 is connected to the smoking chamber 8, and the other end of the connecting pipe 9 is connected to the muffler box 3, so that the airflow can pass through the smoking chamber 8, the connecting pipe 9 and the muffler box 3 in sequence and then reach the fan 2 located in the chassis 1. In this embodiment, the connecting pipe 9 is made of a flexible material and can be bent to a certain extent as needed to ensure that the smoking chamber 8, the connecting pipe 9 and the muffler box 3 can be connected.

[0042] Along the airflow direction, the length of the muffler box 3 can be increased or decreased according to the rotation speed of the fan 2. The change in the length of the muffler box 3 can consume noise energy, and different lengths of the muffler box 3 can reduce noise in different noise frequency bands and reduce airflow noise. Specifically, increasing the length of the muffler box 3 can move the center frequency of the arch curve used to characterize the transmission loss to low frequency, thereby reducing low-frequency noise.

[0043] By setting a silencer box 3 between the connecting pipe 9 and the chassis 1, the silencer box 3 can automatically adjust its own length according to the rotation speed of the fan 2, so as to achieve the purpose of noise reduction and provide a better user experience; the silencer box 3 extends the distance from the chassis 1 to the connecting pipe 9, and further weakens the noise transmitted to the smoking chamber 8 by increasing the spatial distance.

[0044] On the basis of the above structure, the fan installation structure further includes a driving member 4, a lead screw 5 and a slider 6 with a built-in threaded hole 61. One end of the lead screw 5 is connected to the rotation output end of the driving member 4, and the other end of the lead screw 5 is inserted into the threaded hole 61. When the lead screw 5 rotates around its own axis, the slider 6 can move along the axial direction of the lead screw 5.

[0045] The chassis 1 is sleeved on the air outlet end of the muffler box 3, one of the driving member 4 and the slider 6 is arranged in the chassis 1, and the other of the driving member 4 and the slider 6 is arranged in the muffler box 3. The rotation of the lead screw 5 can drive the chassis 1 and the muffler box 3 to slide relative to each other through the slider 6. In order to improve the stability of operation, the lead screw 5 has a self-locking function, so that the chassis 1 can neither move away from the muffler box 3 nor approach the muffler box 3, and the length of the muffler box 3 is maintained at a fixed value.

[0046] like Figure 1 and Figure 2 As shown, the fan installation structure also includes a hanging plate 7 fixedly connected to the roof of the house. The hanging plate 7 includes a chassis mounting portion 71 and a muffler box mounting portion 72, the chassis 1 is connected to the chassis mounting portion 71, and the muffler box body 3 is fixedly connected to the muffler box mounting portion 72, and the connection structure is stable.

[0047] In order to make the chassis 1 slide more smoothly relative to the muffler box 3, a tray-hanging slide 73 is provided on the chassis mounting portion 71, and a chassis tray-hanging slide 11 matching with the tray-hanging slide 73 is provided on the chassis 1, and the chassis 1 is slidably connected to the chassis mounting portion 71. The specific structures of the tray-hanging slide 73 and the chassis tray-hanging slide 11 are not limited. In this embodiment, the tray-hanging slide 73 includes two L-shaped hooks respectively located on both sides of the tray 7, and the bottom of the hooks both extend toward the center of the tray 7; the chassis tray-hanging slide 11 is a convex ridge provided on the side wall of the chassis 1 and protruding toward the tray-hanging slide 73. After the convex ridge is inserted into the hook, the bottom edge of the hook is located below the lower surface of the convex ridge, and the side wall of the hook is located on the outside of the side edge of the convex ridge (the side away from the chassis 1).

[0048] The combined structure of the hanging plate slide 73 and the chassis hanging plate slide 11 can limit the moving direction of the chassis 1 and play a guiding role, ensuring that the chassis 1 will not move or fluctuate in the vertical direction, making it safer to use; moreover, the combined structure of the hanging plate slide 73 and the chassis hanging plate slide 11 can provide supporting force for the chassis 1, making the spatial state of the chassis 1 more stable.

[0049] like Figure 1 , Figure 3 and Figure 4 As shown, the silencer box 3 is a hollow structure, and a silencer box air outlet 32 ​​is formed at one end facing the chassis 1. An opening is also formed on the chassis 1 at one end facing the silencer box 3. The silencer box air outlet 32 ​​is penetrated through the opening of the chassis 1, and the chassis 1 and the silencer box 3 are sleeve-connected.

[0050] The muffler box body 3 is provided with a muffler box slide 33, and the chassis 1 is provided with a chassis muffler box slide 12 that matches the muffler box slide 33. The chassis 1 can slide along the muffler box slide 33 to increase or decrease the length of the muffler box body 3. The specific structures of the muffler box slide 33 and the chassis muffler box slide 12 are not limited, as long as they can play a guiding and supporting role.

[0051] In this embodiment, the muffler box slide 33 is two grooves on the two side walls of the muffler box 3 that are respectively recessed toward the inside of the muffler box 3, and the extending direction of the grooves is the same as the airflow direction; the chassis muffler box slide 12 is two grooves on the two side walls of the chassis 1 that are respectively recessed toward the inside of the chassis 1, and the extending direction of the grooves is the same as the airflow direction. After installation, the grooves on the chassis 1 can be inserted into the grooves on the muffler box 3. When the driving member 4 is started, when the chassis 1 slides relative to the muffler box 3, the grooves on the chassis 1 can slide along the grooves on the muffler box 3.

[0052] On the basis of the above structure, two air inlets 31 are provided on the muffler box 3, and the airflow can reach the fan 2 after entering the muffler box 3 from any air inlet 31. The top of the connecting pipe 9 is connected to one of the air inlets 31, and which of the two air inlets 31 is connected depends on the use environment, and the other air inlet 31 can be blocked by a baffle (not shown) or other devices. The setting of the two air inlets 31 is convenient for switching and can adapt to various use environments, avoid interference with surrounding objects, and allow the oil smoke airflow to enter the muffler box 3 more smoothly, with a wider range of applications.

[0053] The specific shape and location of the air inlet 31 are not limited, as long as it helps the oil fume gas to smoothly enter the muffler box 3. In this embodiment, the air inlet 31 is rectangular, and the long side of the air inlet 31 extends in a square shape consistent with the airflow direction. Regarding the location of the air inlet 31, it cannot be directly attached to the entrance of the chassis 1, and the oil fume airflow needs to flow for a certain distance in the muffler box 3. If the oil fume airflow enters the air inlet 31 and directly enters the chassis 1, the muffler box 3 will not play the role of noise reduction and silencing.

[0054] In order to prevent the air inlet 31 from being blocked when the chassis 1 slides relative to the muffler box 3, as shown in FIG. Figure 1 and Figure 5As shown, a telescopic wall 13 is provided on the chassis 1 , wherein a movable end 131 of the telescopic wall 13 is fixedly connected to a side wall of the chassis 1 , and a fixed end 132 of the telescopic wall 13 is fixedly connected to the muffler box 3 .

[0055] like Figure 6 As shown, the chassis 1 moves relative to the muffler box 3 ( Figure 6 The straight line with an arrow in the middle shows the moving direction of the chassis 1), the fixed end 132 is stationary relative to the chassis 1; the moving end 131 moves with the chassis 1 close to the muffler box 3, and the distance between the fixed end 132 and the moving end 131 is shortened, that is, the length of the telescopic wall 13 along the airflow direction becomes smaller, such as Figure 7 As shown, it is ensured that the telescopic wall 13 never blocks the air inlet 31.

[0056] The specific structure and preparation material of the telescopic wall 13 are not limited, as long as the bottom surface of the chassis 1 can be always closed and the telescopic wall 13 can be compressed and extended. In this embodiment, the telescopic wall 13 is made of a flexible material, and when the chassis 1 moves relative to the muffler box 3, the telescopic wall 13 can be deformed to change the distance between the fixed end 132 and the movable end 131.

[0057] On the basis of the above structure, a receiving cavity 14 is provided on the chassis 1, and the side of the telescopic wall 13 is embedded in the receiving cavity 14. When the chassis 1 moves relative to the muffler box 3, the side of the telescopic wall 13 moves in the receiving cavity 14, playing a guiding and supporting role, ensuring that the telescopic wall 13 will not be deformed during the movement of the chassis 1; the receiving cavity 14 can shield the side of the telescopic wall 13, and the oil droplets condensed in the chassis 1 will fall along the surface of the receiving cavity 14 onto the telescopic wall 13, and will not seep out from the gap between the telescopic wall 13 and the chassis 1, so that the surrounding environment is cleaner and the user experience is good.

[0058] The range hood control method is as follows: the noise spectrum F and the speed n of the fan impeller under different air volumes of the fan 2 are measured in a laboratory, and the control device records the entire noise spectrum F and the speed n of the fan impeller; the spectrum segment F1-F2 that needs to be reduced under the speed n is determined according to the noise spectrum F. In this embodiment, F1-F2 is the low-frequency part of the noise spectrum F, and the user experience is better after eliminating the noise in this frequency band. The specific values ​​of F1 and F2 are not limited and can be determined according to the specific needs of the user.

[0059] The length L of the muffler box 3 along the airflow direction is calculated by the transmission loss formula, and the length L is mapped to the rotation speed n one by one to form an nL table. The control device may store only one nL table, or may store two or more nL tables according to different working gears of the range hood. It should be noted that the corresponding relationship between the length L and the rotation speed n may also be determined by other methods to meet the needs of the user.

[0060] Start the range hood, determine the current length of the muffler box 3 along the airflow direction and the speed n1 of the fan impeller, and query the length L1 corresponding to the speed n1 through the nL table. The control device starts the driving member 4, and the chassis 1 slides relative to the muffler box 3, thereby increasing or reducing the length of the muffler box 3 to L1. By looking up the table, the length of the muffler box 3 corresponding to the current fan impeller speed can be quickly and accurately obtained, and the range hood responds faster.

[0061] In this embodiment, the control device can be a centralized or distributed controller. For example, the controller can be a single single-chip microcomputer or a distributed plurality of single-chip microcomputers. The control program can be run in the single-chip microcomputer to control the drive element 4 and the fan 2 to realize their functions.

[0062] The specific method of "the control device starts the driving member 4, and the chassis 1 slides relative to the silencer box 3, thereby increasing or reducing the length of the silencer box 3 to L1" is not limited. In this embodiment, after the range hood is started, the control device determines whether the slider 6 is reset. If so, the gear position is detected and the corresponding nL curve is called; otherwise, the driving member 4 is started, the slider 6 is retracted to the reset position, the gear position is detected and the corresponding nL curve is called; the current displacement L2=0 is recorded. The current fan speed n1 is detected, and the corresponding length L1 of the silencer box 3 is obtained by looking up the table or calculating. The stroke difference ΔL of the slider 6 is calculated to be ΔL=L1-L2. Determine whether the stroke difference ΔL satisfies and is greater than 0. If so, the driving member 4 is rotated forward to push the chassis 1 out by ΔL, and L2=L2+ΔL is recorded; otherwise, the driving member 4 is reversed to retract the chassis 1 by ΔL, and L2=L2+ΔL is recorded. The control device detects whether the range hood is turned off. If so, the driving member 4 is reversed and the slider 6 is retracted to the reset position; otherwise, the control device returns to the detection position and calls the corresponding nL curve.

[0063] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. The fan installation structure is characterized by: include: A fan assembly comprises a chassis (1) and a fan (2) arranged in the chassis (1); as well as, The silencer assembly comprises a silencer box (3) connected to the chassis (1); along the airflow direction, the length of the silencer box (3) can be increased or decreased according to the rotation speed of the fan (2) to reduce the airflow noise.

2. The fan installation structure according to claim 1, characterized in that: The fan installation structure further comprises a driving member (4), a lead screw (5) and a slider (6) having a threaded hole (61) therein, one end of the lead screw (5) being connected to the rotation output end of the driving member (4), the other end of the lead screw (5) being inserted into the threaded hole (61), and when the lead screw (5) rotates around its own axis, the slider (6) can move along the axis direction of the lead screw (5); The chassis (1) is sleeved on the air outlet end of the muffler box (3); one of the driving member (4) and the slider (6) is arranged in the chassis (1); the other of the driving member (4) and the slider (6) is arranged in the muffler box (3); the rotation of the lead screw (5) can drive the chassis (1) and the muffler box (3) to slide relative to each other through the slider (6).

3. The fan installation structure according to claim 1, characterized in that: The fan installation structure also includes a hanging plate (7), the hanging plate (7) includes a chassis installation portion (71) and a muffler box installation portion (72), the chassis (1) is connected to the chassis installation portion (71), and the muffler box body (3) is fixedly connected to the muffler box installation portion (72).

4. The fan installation structure according to claim 3, characterized in that: The chassis mounting portion (71) is provided with a plate-hanging sliding member (73), the chassis (1) is provided with a chassis plate-hanging sliding member (11) that matches the plate-hanging sliding member (73), and the chassis (1) is slidably connected to the chassis mounting portion (71).

5. The fan installation structure according to any one of claims 1 to 4, characterized in that: The muffler box (3) is a hollow structure, and a muffler air outlet (32) is formed at one end facing the chassis (1). The muffler box (3) is provided with a muffler sliding member (33), and the chassis (1) is provided with a chassis muffler sliding member (12) that matches the muffler sliding member (33). The chassis (1) can slide along the muffler sliding member (33) to increase or decrease the length of the muffler box (3).

6. The fan installation structure according to any one of claims 1 to 4, characterized in that: The muffler box (3) is provided with two air inlets (31), and airflow can reach the fan (2) after entering the muffler box (3) from any of the air inlets (31).

7. The fan installation structure according to claim 6, characterized in that: The chassis (1) is provided with a telescopic wall surface (13); a movable end (131) of the telescopic wall surface (13) is fixedly connected to a side wall surface of the chassis (1); a fixed end (132) of the telescopic wall surface (13) is fixedly connected to the muffler box (3); when the chassis (1) moves relative to the muffler box (3), the telescopic wall surface (13) never blocks the air inlet (31).

8. The fan installation structure according to claim 7, characterized in that: The case (1) is provided with a receiving cavity (14), and the side edge of the telescopic wall surface (13) is embedded in the receiving cavity (14); when the case (1) moves relative to the muffler box (3), the side edge of the telescopic wall surface (13) moves in the receiving cavity (14).

9. A range hood, comprising a smoke extraction chamber (8) and a connecting pipe (9), characterized in that: The range hood further comprises a fan mounting structure as claimed in any one of claims 1 to 8, one end of the connecting pipe (9) is connected to the smoking chamber (8), and the other end of the connecting pipe (9) is connected to the silencer box (3), so that the airflow can pass through the smoking chamber (8), the connecting pipe (9) and the silencer box (3) in sequence and then reach the fan (2) located in the chassis (1).

10. A method for controlling a range hood, characterized in that: include: measuring and recording the noise spectrum F of the fan (2) at different air volumes and the rotation speed n of the fan impeller, and determining the spectrum segment F1-F2 that needs to be reduced at the rotation speed n according to the noise spectrum F; The length L of the silencer box (3) along the airflow direction is calculated by the transmission loss formula, and the length L is matched with the rotation speed n to form an nL table; Start the range hood, determine the current length of the muffler box (3) along the airflow direction and the speed n1 of the fan impeller, query the length L1 corresponding to the speed n1 through the nL table, and increase or decrease the length of the muffler box (3) to L1.

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