Range hood and control method thereof

Abstract

The invention discloses a range hood and a control method thereof, the range hood comprises: a smoke collecting hood, the front side of which is provided with a smoke inlet; the smoke baffle can open and close the smoke inlet; the movement mechanism is used for driving the smoke barrier and comprises a driving mechanism and a transmission mechanism for transmitting the output of the driving mechanism to the smoke barrier; the moving mechanism further comprises a first mounting support and a second mounting support arranged on the front side of the first mounting support, the two mounting supports are detachably connected with the top of the exhaust fume collecting hood, the driving mechanism is mounted on the first mounting support, the input end of the transmission mechanism is in transmission connection with the driving mechanism, and the output end of the transmission mechanism is in transmission connection with the exhaust fume collecting hood. The output end of the transmission mechanism is detachably connected with the smoke barrier and further connected with the second installation support.

Description

Technical Field

[0001] The present invention relates to an oil fume purification device, in particular to a range hood and a control method of the range hood. Background Art

[0002] Range hoods have become one of the indispensable kitchen appliances in modern families. Side-suction range hoods have become the mainstream of the market due to their strong smoke extraction effect. In side-suction range hoods, in order to expand the smoke collection range, a smoke baffle that can be opened and closed is usually provided. The motion mechanism used to drive the movement of the smoke baffle is a relatively important part of the whole machine, among which the use of a worm gear reduction motor as a driver is a more conventional and widespread method. As disclosed in the Chinese patent application number 202010609847.5 of the applicant. After long-term use, the motion mechanism is prone to malfunction, resulting in the inability to turn on the machine when the smoke baffle is closed, and it cannot be disassembled for maintenance, and when it is opened to the maximum angle, abnormal noise will be generated.

[0003] In view of the fact that the movement mechanism of the range hood is difficult to repair, the existing technology mainly improves it in the following aspects:

[0004] 1. As disclosed in the Chinese patent application number 202123077126.3, a maintenance window is expanded on the top of the rear panel of the range hood, so that the movement mechanism can be easily disassembled even when the drive mechanism is locked, which facilitates maintenance. However, it affects the appearance and has poor applicability. The maintenance window designed on the box body is prone to deformation, increases manufacturing costs, increases maintenance steps, and is not easy to repair.

[0005] 2. As disclosed in the Chinese patent application number 202122621046.3, the moving component is fixed to the panel. By removing the glass plate on the panel, when a failure occurs and the smoke baffle is closed and locked, the moving component can be removed for easy maintenance. However, the applicability is poor, for example, it cannot be applied to a one-stage range hood.

[0006] 3. As disclosed in Chinese patent application number 201720610367.4, a semicircular tightening method is adopted at both ends of the range hood shaft, so that the shaft assembly can be directly taken up and down during assembly and maintenance, which greatly improves production and maintenance efficiency. However, when the range hood motor cannot be turned on due to an abnormality, it is impossible to access both ends of the shaft to remove the smoke baffle, which affects the smoothness and time of the entire machine opening process and affects the user experience.

[0007] To address the issue of abnormal noise generated during the opening process and when the range hood's movement mechanism is opened to its maximum angle, existing technologies often employ methods such as reducing the speed of the reduction motor throughout its entire operation or increasing hinge damping to mitigate the noise generated when opening to its maximum angle. For example, Chinese patent application number 202310889274.X determines whether the smoke damper is in an abnormal state by determining the distance, changing the current, and applying external force to reduce the hinge's opening and closing speed. However, the method for determining motor noise and abnormal noise is unclear. Furthermore, increasing the damper current to increase external resistance, thereby changing the hinge's movement speed, places high demands on the hinge's strength and can easily damage it. Another example is patent application number 201811115630.8, which subjectively determines whether the noise is appropriate based on the speed difference, and adjusts the speed and torque to achieve the goal of reducing vibration and noise. However, this solution is primarily designed to avoid noise and abnormal sound. In actual use, the hinge will continue to wear and tear, making it impossible to achieve a practical adjustment effect. Summary of the Invention

[0008] The first technical problem to be solved by the present invention is to provide a range hood that is convenient for maintenance of the movement mechanism in view of the deficiencies in the above-mentioned prior art.

[0009] The second technical problem to be solved by the present invention is to provide a control method for a range hood to reduce vibration and abnormal noise in response to the above-mentioned deficiencies in the prior art.

[0010] The technical solution adopted by the present invention to solve the first technical problem is: a range hood comprising:

[0011] A smoke collecting hood, the front side of which is provided with a smoke inlet;

[0012] Smoke dampers, which open and close the smoke inlet; and

[0013] A motion mechanism for driving the smoke shield, comprising a drive mechanism and a transmission mechanism for transmitting the output of the drive mechanism to the smoke shield; characterized in that:

[0014] The motion mechanism also includes a first mounting bracket and a second mounting bracket arranged in front of the first mounting bracket. Both mounting brackets are detachably connected to the top of the smoke hood. The driving mechanism is installed on the first mounting bracket. The input end of the transmission mechanism is transmission-connected to the driving mechanism. The output end of the transmission mechanism is detachably connected to the smoke shield. The output end of the transmission mechanism is also connected to the second mounting bracket.

[0015] Therefore, the motion mechanism is designed to be split (the mounting bracket is divided into two), so that the motion mechanism can be in a small space. When the motor cannot be turned on due to an abnormality, just remove the two mounting brackets, and then pass the connection between the transmission mechanism and the smoke shield through the motion mechanism avoidance position at the left and right ends of the front side of the smoke hood. After that, the smoke shield and the transmission mechanism can be disassembled to achieve normal disassembly of the smoke shield for subsequent maintenance.

[0016] Preferably, the structure of the transmission mechanism is that the transmission mechanism includes a first connecting rod, a second connecting rod and a rocker serving as the output end of the transmission mechanism, the first connecting rod serves as the input end of the transmission mechanism and is transmission-connected to the driving mechanism, the first connecting rod is also rotationally connected to one end of the second connecting rod, the second connecting rod is rotationally connected to the rocker, the rocker is also rotationally connected to the second mounting bracket, and the rocker is also detachably connected to the smoke shield.

[0017] To facilitate driving the transmission mechanism, the driving mechanism includes a motor and an output shaft, and the output shaft passes through the first connecting rod and is fixed to the first connecting rod.

[0018] In order to avoid excessive output torque of the motor, which may cause deformation of the transmission mechanism and affect the movement of the entire motion mechanism, the output shaft passes through the first mounting bracket and is rotatably supported on the first mounting bracket. The first mounting bracket supports the output shaft on both sides of the first connecting rod.

[0019] Preferably, in order to facilitate the connection between the smoke shield and the transmission mechanism, a smoke shield bracket is provided on the back side of the smoke shield facing the smoke collecting hood, and the smoke shield is fixed to the rocker via the smoke shield bracket.

[0020] Furthermore, in order to avoid noise when the transmission mechanism and the limiting structure collide, the motion mechanism also includes a flexible damping member. A limiting portion is provided on the first mounting bracket, and the limiting portion is located below the first connecting rod. The flexible damping member is provided on the limiting portion. When the smoke shield is opened, the first connecting rod can abut against the flexible damping member.

[0021] The technical solution adopted by the present invention to solve the second technical problem is: a control method of the range hood as described above, characterized in that it includes the following steps:

[0022] 1) Acquire the sound signal y(t) of the smoke shield when it is stationary and in motion, where t is the acquisition time, and divide the acquired signal y(t) into frames;

[0023] 2) Perform FFT on the framed signal to obtain a frequency domain signal. The signals corresponding to the smoke deflector's static and moving states are intercepted and then subjected to ambient noise reduction to obtain the single motion sound spectrum of the smoke deflector.

[0024] 3) Divide the motor sound frequency band and the transmission mechanism friction sound frequency band, and calculate the real-time PSD of the motor sound based on the sound spectrum obtained in step 2), which is recorded as S′ motor , and the real-time PSD of the friction sound of the transmission mechanism, denoted as S′ friction ;

[0025] 4) Compare with the set benchmark PSD and perform corresponding processing based on the comparison value:

[0026] The motor sound abnormality judgment: If The motor is judged to have abnormal noise, and the input voltage of the motor is controlled to decrease until like The motor is judged to be abnormal and needs to be repaired and a prompt is given;

[0027] Judgment of abnormal friction sound of transmission mechanism: If It is judged that there is an abnormality in the transmission mechanism and a prompt is given;

[0028] Among them, S motor The preset motor sound baseline PSD, S friction It is the preset benchmark PSD of the transmission mechanism friction sound.

[0029] Through the above detection, calculation and control, on the basis of the structure of the motion mechanism avoiding collision sounds, further avoidance or early warning of abnormalities in the motor and transmission mechanism are achieved, thereby reducing the vibration and abnormal noise of the motion mechanism and eliminating faults in a timely manner.

[0030] Preferably, in order to reduce spectrum leakage and boundary effects caused by signal truncation, in step 1), the audio y(t) collected before and during the movement of the smoke shield is framed and multiplied by the window function w(t) to obtain the nth frame signal:

[0031] y n (t)=y(t+nH)·w(t), where n is the number of sub-frames, H is the frame shift, and the frame length is N.

[0032] Furthermore, the method for removing the ambient sound is as follows: in step 2), each frame signal y after framing is n (t) Perform FFT to obtain the complex spectrum Y n (k) = FFT{y n (t)}, k is the frequency point, and the spectrum amplitude A n (k) and phase θ n (k) are respectively expressed as:

[0033] A n (k)=|Y n (k)|,θ n (k) = arg(Y n (k));

[0034] Intercept the ambient sound signal when the smoke shield is stationary and calculate the ambient sound spectrum N(k):

[0035]

[0036] Among them, N s is the number of frames of the ambient sound signal;

[0037] Subtract the ambient sound spectrum from the sound spectrum of the smoke deflector in motion to obtain the corrected single motion sound spectrum:

[0038]

[0039] Where α is the over-subtraction coefficient, and the value range of α is 1 to 2; β is the lower limit coefficient, and the value range of β is 0.01 to 0.1; the corrected amplitude spectrum and the original phase information are synthesized into a complex spectrum:

[0040]

[0041] Furthermore, the method for calculating the real-time PSD is that in step 3), the friction sound of the transmission mechanism is in the high spectrum band, and the corresponding lower limit frequency is The corresponding upper frequency limit is The sound of the motor is in the low frequency band, and the corresponding lower limit frequency is The corresponding upper frequency limit is

[0042] Then by the formula Calculate the actual frequency of the motor sound and the friction sound of the transmission mechanism in the complex spectrum, where Δf is the frequency resolution, F s is the sampling rate:

[0043] The two extreme frequency points of the motor sound are:

[0044] The two extreme frequency points of the friction sound of the transmission mechanism are:

[0045] From this we get:

[0046]

[0047] Compared with the prior art, the advantages of the present invention are: the motion mechanism is designed to be split (the mounting bracket is divided into two), so that the motion mechanism can be in a small space, and when the motor cannot be turned on due to an abnormality, only the two mounting brackets need to be removed, and then the connection between the transmission mechanism and the smoke baffle is passed through the motion mechanism avoidance position at the left and right ends of the front side of the smoke hood. After that, the smoke baffle and the transmission mechanism can be disassembled to achieve normal disassembly of the smoke baffle for subsequent maintenance; through the sound detection, calculation and control of the smoke baffle when it is stationary and in motion, on the basis of the structure of the motion mechanism avoiding the collision sound, further avoidance or warning of abnormalities of the motor and transmission mechanism can be made, thereby reducing the jitter and abnormal noise of the motion mechanism and timely troubleshooting. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic diagram of a range hood according to an embodiment of the present invention;

[0049] Figure 2 A schematic diagram of a hidden portion of a smoke collecting hood of a range hood according to an embodiment of the present invention;

[0050] Figure 3 is a schematic diagram of a motion mechanism of a smoke baffle of a range hood according to an embodiment of the present invention;

[0051] Figure 4 for Figure 3 A schematic diagram showing the first mounting bracket is hidden;

[0052] Figure 5 This is a flow chart of a control method for a range hood according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions.

[0054] 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. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Since the embodiments disclosed in the present invention can be set in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of such features.

[0055] See also Figures 1 to 4 A range hood includes a smoke collecting hood 1, a smoke inlet 11 is provided on the front side of the smoke collecting hood 1, and the range hood also includes a smoke baffle 2 capable of opening and closing the smoke inlet 11.

[0056] In order to facilitate the automatic driving of the smoke baffle 2, the range hood also includes a motion mechanism. The motion mechanism includes a drive mechanism 31, a transmission mechanism, a first mounting bracket 331 and a second mounting bracket 332. The first mounting bracket 331 is arranged on the rear side of the second mounting bracket 332. Both mounting brackets are located in the smoke hood 1 and can be fixed to the top of the smoke hood 1. Each mounting bracket can be detachably connected to the smoke hood 1 by screws. The drive mechanism 31 preferably includes a motor 311 and an output shaft 312. In this embodiment, the output shaft 312 can be perpendicular to the axial direction of the motor 311. The output shaft 312 is driven by the motor 311 to rotate around its own axis. The relationship between the two can also be in the same direction. The output shaft 312 can also be the axis of the motor 311 itself. The motor 311 is mounted on the first mounting bracket 331. The output shaft 312 passes through the first mounting bracket 331 and is rotatably supported on the first mounting bracket 331. The output shaft 312 extends in the left and right directions of the range hood.

[0057] The transmission mechanism includes a first connecting rod 321, a second connecting rod 322, and a rocker 323. The first connecting rod 321 serves as the input end of the transmission mechanism, while the rocker 323 serves as the output end. The output shaft 312 passes through the first connecting rod 321 and is fixed thereto, achieving a transmission connection. Rotation of the output shaft 312 drives the first connecting rod 321 about its axis. The first connecting rod 321 is also rotationally connected to one end of the second connecting rod 322. The second connecting rod 322 is rotationally connected to the rocker 323, which is also rotationally connected to the second mounting bracket 332. The first connecting rod 321 rotates about a fixed axis relative to the first mounting bracket 331, while the rocker 323 rotates about a fixed axis relative to the second mounting bracket 332. Both rotation axes extend left and right along the range hood. A smoke damper bracket 21 is provided on the back of the smoke damper 2 facing the smoke hood 1, and the rocker 323 is also detachably connected to the smoke damper bracket 21 (commonly fixed by screws so that the rocker 323 and the smoke damper 2 rotate synchronously), thereby the motion mechanism can drive the smoke damper 2 to move.

[0058] Therefore, the motion mechanism is designed to be split (the mounting bracket is divided into two), so that the motion mechanism can be in a small space. When the motor 311 cannot be turned on due to an abnormality, it is only necessary to remove the two mounting brackets (the screws fixing the two mounting brackets to the smoke hood 1 are driven in from the top of the smoke hood 1, so they can be directly removed). Then, the connection between the rocker arm 323 and the smoke damper bracket 21 is passed through the motion mechanism avoidance position at the left and right ends of the front side of the smoke hood 1 (this type of machine has it. When the smoke damper 2 is opened, the motion mechanism needs to partially pass through the smoke hood 1 to drive the smoke damper 2 to open forward). After that, the smoke damper 2 and the rocker arm 323 can be disassembled to achieve normal disassembly of the smoke damper 2. If the mounting bracket is integrated, it is too large and the moving space is limited, so that the connection between the smoke damper 2 and the rocker arm 323 cannot be passed through, and the smoke damper 2 cannot be disassembled. This method is suitable for side-suction range hoods in which the mounting bracket is fixed to the top of the smoke hood 1.

[0059] In order to prevent the output torque of the motor 311 from being too large, which would cause deformation of the transmission mechanism and affect the movement of the entire motion mechanism, the first mounting bracket 331 provides a bilateral support structure for the output shaft 312. For example, the portion of the first mounting bracket 331 through which the output shaft 312 passes can be roughly U-shaped, that is, the output shaft 312 can be supported at two positions on the left and right sides of the first connecting rod 321.

[0060] The motion mechanism also includes a flexible damping member 34. A limit portion 3311 is provided on the first mounting bracket 331. The limit portion 3311 is located below the first connecting rod 321, and the flexible damping member 34 is mounted on the limit portion 3311. Preferably, the flexible damping member 34 is a compression spring. When the end of the first connecting rod 321 away from the output shaft 312 rotates downward to a preset position (the smoke baffle 2 is fully opened), the bottom portion corresponding to the connection between the first connecting rod 321 and the second connecting rod 322 abuts against the flexible damping member 34. In conjunction with the current detection of the motor 311, the motion mechanism can be operated to its maximum position without producing any metallic collision noise.

[0061] Specifically, the flexible damping member 34 occupies a small space. Before the smoke deflector 2 reaches its maximum opening angle, it continuously increases the resistance experienced by the motor 311 before stopping. This causes the operating current of the motor 311 to continuously increase. When the detected current exceeds the stall current, it indicates that the preset position has been reached. Simultaneously, the compression of the flexible damping member 34 has not yet reached its maximum value. At this point, the motor 311 is controlled to stop, achieving the desired opening position while avoiding noise generation from collision with the limiter 3311. This entire structural solution is suitable for currently common automatic flap structures and only affects the transmission mechanism when the smoke deflector 2 is opened to its maximum angle, with minimal overall impact on the transmission mechanism.

[0062] When the flexible damping member 34 is a compression spring, its elastic force F 弹 =2kx, where x is the compression amount of the compression spring when the smoke shield 2 reaches the preset position (less than the maximum compression amount of the compression spring), k is the elastic coefficient, and the torque T of the motor 311 is 电机 =F 弹 l, where l is the distance between the axis of the output shaft 312 and the center of the connection between the first connecting rod 321 and the second connecting rod 322 (i.e., the lever arm), then Thereby, a suitable compression spring can be selected.

[0063] The above structure of the motion mechanism is the active end. The motion mechanism may further include a driven end, which only has the second mounting bracket 332 and the rocker 323 .

[0064] During the opening and closing of the smoke deflector 2, the range hood produces the following noises: fan noise, motor noise, metal friction noise from the transmission mechanism, and the metal limiter collision noise between the transmission mechanism and the first mounting bracket 331. (When the deflector 2 is fully opened, this collision noise is almost non-existent due to the flexible damping member 34.) To identify abnormal noise during the opening and closing of the smoke deflector 2, the influence of fan noise must be avoided. To this end, the fan is not started during the opening process of the smoke deflector 2 until the smoke deflector 2 is fully opened to avoid the influence of fan noise. Furthermore, the fan is turned off before the smoke deflector 2 is closed to avoid the influence of fan noise.

[0065] For the remaining motor sounds and transmission mechanism metal friction sounds, the system identifies whether the sounds are abnormal. If so, it determines whether the abnormality lies in the motor 311 or the transmission mechanism. If the abnormality lies in the motor 311, the system controls the input voltage to the motor 311 during the period of time when the abnormal sound occurs, minimizing the noise when the range hood is opened to the critical angle. If the abnormality lies in the transmission mechanism, a warning is issued indicating that the transmission mechanism needs to be lubricated.

[0066] For details, see Figure 5 , the process of identifying abnormal sounds and the subsequent corresponding processing includes the following steps:

[0067] 1) Acquire the sound signal y(t) of the smoke shield 2 when it is stationary and in motion, where t is the acquisition time. In this step, the sound signal can be acquired using a MEMS microphone sensor. Since the characteristics of the sound signal within a short time range can be considered stable, the above signal y(t) is framed and multiplied by a window function w(t). The window function can smoothly transition between the two ends of each frame, thereby reducing spectrum leakage and boundary effects caused by signal truncation. The signal y of the nth frame (n is the number of frames; in this embodiment, n = 0, 1, 2, ..., 20) used after the signal is framed is obtained: n (t) = y(t+nH)·w(t), where H is the frame shift and N is the frame length. In this embodiment, H = 500 and N = 1000;

[0068] In this embodiment, the window function w(t) may be a Hamming window function: This function is an existing technology and will not be described in detail here;

[0069] 2) Perform environmental noise reduction on the collected sound signal. This step can be achieved using spectral subtraction, using Fast Fourier Transform (FFT) to obtain the frequency domain signal for environmental noise reduction:

[0070] Each frame signal y after framing n (t) Perform FFT to obtain the complex spectrum Y n (k) = FFT{y n (t)}, k is the frequency point, and the spectrum amplitude A n (k) and phase θ n (k) are respectively expressed as:

[0071] A n (k)=|Y n (k)|,θ n (k) = arg(Y n (k));

[0072] Extract the complex spectrum Y n (k) corresponds to the ambient sound signal when the smoke baffle 2 is stationary, and the ambient sound spectrum N(k) is calculated:

[0073]

[0074] Among them, N s is the number of frames of the ambient sound signal, which is determined during the framing in step 1);

[0075] The complex spectrum Y n The sound spectrum corresponding to the movement of the smoke baffle 2 in (k) is subtracted from the above-mentioned ambient sound spectrum N(k) to obtain the corrected single motion sound spectrum:

[0076]

[0077] Wherein, α is the over-subtraction coefficient, which indicates the strength of the sound noise reduction and has a value range of 1 to 2. In this embodiment, it can be set to 1.5. β is the lower limit coefficient, which avoids setting it to a negative value and has a value range of 0.01 to 0.1. In this embodiment, it can be set to 0.05. The corrected amplitude spectrum and the original phase information are synthesized into a complex spectrum:

[0078]

[0079] 3) Divide the motor sound frequency band and the transmission mechanism friction sound (metal friction sound) frequency band, and calculate the power spectrum density value (real-time PSD) of each in real time:

[0080] The metal friction sound of the transmission mechanism is in the high spectrum band (3kHz~6kHz), that is, the corresponding lower limit frequency is The corresponding upper frequency limit is The motor sound is in the low frequency band (800hz~2khz), that is, the corresponding lower limit frequency is The corresponding upper frequency limit is

[0081] By formula Calculate the actual frequency of the metal friction sound and the motor sound in the complex spectrum, where Δf is the frequency resolution. If it can be 1, F s For the sampling rate, for example, 1 khz:

[0082] Motor sound:

[0083] Metal friction sound:

[0084] Calculate the real-time power spectral density (PSD), where S′ motor is the real-time PSD of the motor sound, S′ friction Real-time PSD for metal friction sound:

[0085]

[0086] 4) Compare with the set threshold and perform corresponding processing according to the comparison value:

[0087] Motor sound abnormality judgment: If It is determined that the motor 311 has an abnormal sound, and the power board of the range hood reduces the input voltage by a certain value, such as 0.5V, at the corresponding time point of the corresponding frequency point until it is determined that there is no abnormality after comparing the threshold value. The starting voltage of motor 311 is 12V, and the minimum voltage cannot be less than 6V; if It is determined that the motor 311 is abnormal and needs to be repaired and a prompt is given, such as a whistle warning on the power board;

[0088] Judgment of abnormal metal friction sound: If It is determined that the transmission mechanism is abnormal and a prompt is given, such as a light flashing warning through a switch on the smoke baffle 2.

[0089] Among them, S motor and S friction is a preset threshold value, which can be obtained when the range hood is first used after installation, using the same method as S′ motor and S′ friction .

Claims

1. A range hood comprising: A smoke collecting hood (1) is provided with a smoke inlet (11) on the front side; a smoke baffle (2) capable of opening and closing the smoke inlet (11); as well as A motion mechanism for driving a smoke shield (2), comprising a drive mechanism (31) and a transmission mechanism for transmitting the output of the drive mechanism (31) to the smoke shield (2); characterized in that: The motion mechanism further comprises a first mounting bracket (331) and a second mounting bracket (332) arranged in front of the first mounting bracket (331), both mounting brackets being detachably connected to the top of the smoke hood (1), the driving mechanism (31) being mounted on the first mounting bracket (331), the input end of the transmission mechanism being transmission-connected to the driving mechanism (31), the output end of the transmission mechanism being detachably connected to the smoke baffle (2), and the output end of the transmission mechanism being further connected to the second mounting bracket (332).

2. The range hood according to claim 1, characterized in that: The transmission mechanism comprises a first connecting rod (321), a second connecting rod (322), and a rocker (323) serving as an output end of the transmission mechanism. The first connecting rod (321) serves as an input end of the transmission mechanism and is transmission-connected to the driving mechanism (31). The first connecting rod (321) is also rotationally connected to one end of the second connecting rod (322). The second connecting rod (322) is rotationally connected to the rocker (323). The rocker (323) is also rotationally connected to a second mounting bracket (332). The rocker (323) is also detachably connected to the smoke shield (2).

3. The range hood according to claim 2, characterized in that: The driving mechanism (31) includes a motor (311) and an output shaft (312), wherein the output shaft (312) passes through a first connecting rod (321) and is fixed to the first connecting rod (321).

4. The range hood according to claim 3, characterized in that: The output shaft (312) passes through the first mounting bracket (331) and is rotatably supported on the first mounting bracket (331). The first mounting bracket (331) supports the output shaft (312) on both sides of the first connecting rod (321).

5. The range hood according to claim 2, characterized in that: A smoke baffle bracket (21) is provided on the back side of the smoke baffle (2) facing the smoke collecting hood (1), and the smoke baffle (2) is fixed to the rocker (323) via the smoke baffle bracket (21).

6. The range hood according to claim 2, characterized in that: The motion mechanism further comprises a flexible damping member (34); a limiting portion (3311) is provided on the first mounting bracket (331); the limiting portion (3311) is located below the first connecting rod (321); the flexible damping member (34) is provided on the limiting portion (3311); when the smoke shield (2) is opened, the first connecting rod (321) can abut against the flexible damping member (34).

7. A range hood control method according to claim 3 or 4, characterized in that: The steps include: 1) Acquire the sound signals y(t) of the smoke shield (2) when it is stationary and when it is moving, where t is the acquisition time, and divide the acquired signals y(t) into frames; 2) performing FFT on the framed signal to obtain a frequency domain signal, intercepting the signals corresponding to the stationary state and the moving state of the smoke shield (2), and performing environmental noise reduction to obtain a single moving sound spectrum of the smoke shield (2); 3) Divide the sound frequency band of the motor (311) and the friction sound frequency band of the transmission mechanism, and calculate the real-time PSD of the sound of the motor (311) based on the sound spectrum obtained in step 2), which is recorded as S′ motor , and the real-time PSD of the friction sound of the transmission mechanism, denoted as S′ friction ; 4) Compare with the set benchmark PSD and perform corresponding processing based on the comparison value: The abnormal sound judgment of the motor (311): If It is determined that the motor (311) has an abnormal sound, and the input voltage of the motor (311) is controlled to decrease until like Then it is determined that the motor (311) is abnormal and needs to be repaired and a prompt is given; Judgment of abnormal friction sound of transmission mechanism: If It is judged that there is an abnormality in the transmission mechanism and a prompt is given; Among them, S motor is the preset reference PSD of the motor (311) sound, S friction It is the preset benchmark PSD of the transmission mechanism friction sound.

8. The range hood control method according to claim 7, characterized in that: In step 1), the audio y(t) collected before and during the movement of the smoke shield (2) is divided into frames and multiplied by the window function w(t) to obtain the nth frame signal: y n (t)=y(t+nH)·w(t), where n is the number of sub-frames, H is the frame shift, and the frame length is N.

9. The range hood control method according to claim 8, characterized in that: In step 2), each frame signal y after framing is n (t) Perform FFT to obtain the complex spectrum Y n (k) = FFT{y n (t)}, k is the frequency point, and the spectrum amplitude A n (k) and phase θ n (k) are respectively expressed as: AND n (k)=|Y n (k)|,θ n (k)=arg(Y n (k)); Intercept the ambient sound signal when the smoke shield (2) is stationary and calculate the ambient sound spectrum N(k): Among them, N s is the number of frames of the ambient sound signal; The sound spectrum of the smoke baffle (2) in motion is subtracted from the ambient sound spectrum to obtain the corrected single motion sound spectrum: Where α is the over-subtraction coefficient, and the value range of α is 1 to 2; β is the lower limit coefficient, and the value range of β is 0.01 to 0.1; the corrected amplitude spectrum and the original phase information are synthesized into a complex spectrum:

10. The range hood control method according to claim 9, characterized in that: In step 3), the friction sound of the transmission mechanism is in the high frequency band, and the corresponding lower limit frequency is The corresponding upper frequency limit is The sound of the motor (311) is in the low frequency band, and the corresponding lower limit frequency is The corresponding upper frequency limit is Then by the formula Calculate the actual frequency of the motor sound and the friction sound of the transmission mechanism in the complex spectrum, where Δf is the frequency resolution, F s is the sampling rate: The two extreme frequency points of the sound of the motor (311) are: The two extreme frequency points of the friction sound of the transmission mechanism are: From this we get:

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